JP2003174470A - Data packet transmitter, data packet receiver, data packet transmission system and data packet retransmission control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a useless retransmission even when the retransmission of data and a retransmission request pass each other between a transmitting station and a receiving station. <P>SOLUTION: When a status notice message (STATUS-PDU) is received from a receiving station 2, a transmitting station 1 judges the presence/absence of a retransmission control table and when there is the retransmission control table, the transmitting station refers to the relevant retransmission control table. When the upper limit value of sequence numbers contained in the status notice message is less than the upper limit value of sequence numbers contained in the retransmission control table, the difference of information on a data packet contained in the retransmission control table and the status notice message is extracted and necessity of retransmission is decided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data packet transmitting apparatus for controlling retransmission when transmitting a data packet, a data packet receiving apparatus for making a retransmission request for a received data packet, wired or wireless communication. TECHNICAL FIELD The present invention relates to a data packet transmission system and a data packet retransmission control method for performing transmission / reception of data packets while performing retransmission control between a data packet transmission device and a data packet reception device connected by a line, The present invention relates to a data packet transmission system and a data packet retransmission control method for transmitting and receiving by transmitting and receiving.

[0002]

2. Description of the Related Art As a data packet retransmission control method in a communication system in which a plurality of data are collectively transmitted and received, for example, one method of IMT-2000 is 3
Radio Link Control (RLC: Radio Link Control) established by the 3rd Generation Partnership Project (GPP)
l) protocol specification TS 25.322 V3.5.0
The method described in (2000-12) is conventionally known.

A data packet retransmission control method described in the protocol specifications of radio link control established by 3GPP will be described below with reference to FIGS. 22 to 26. 22. FIG. 22 is a sequence diagram illustrating a conventional data packet retransmission control method. FIG. 23 is a diagram showing a format example of a data packet transmitted by a conventional transmitting station. FIG. 24 is a diagram showing a format example of a state notification message transmitted by a conventional receiving station. FIG. 25 is a diagram showing a format example of the delivery confirmation information element included in the status notification message. FIG. 26 is a diagram showing a format example of the retransmission request information element included in the status notification message.

First, the contents of the format will be described. In FIG. 23, a data packet (hereinafter referred to as “RLC-PDU”. PDU: Protocol Data Unit) 300a includes “D / C” 301 and “Sequ” in the data units of the first row and the second row.
ence Number ”302,“ P ”303, and“ HE ”304
Are provided, and "Length Indicato"
r "307-1 to 307-N and" E "305-1 to 30
5-N are provided, and the data section "Dat
a ”308 is provided.

"D / C" 301 is the RLC-PDU 300 concerned.
It is a flag indicating whether a is user data or control data. "Sequence Number" 302 is the RLC-P
This is the sequence number of the DU 300a. "P" 303 is
This is a flag (called Poll bit) that requests a status notification message. "HE" 304 and "E" 30
5-1 to 305-N are flags indicating the presence or absence of subsequent header information. "Length Indicator" 307-1 to 30
7-N indicates the effective data length of the data part “Data” 308, and is set only when the end of the PDU of the upper layer is included.

In FIG. 24, a status notification message (hereinafter referred to as "STATUS-PDU") 310a is "D / C".
301, "PDU type" 311, and "SUFI ₁ " 313-1.
It is composed of "SUFI _K " 313-K (hereinafter referred to as "SUFI" 313) and "PAD" 314.

"D / C" 301 is the STATUS-PDU3
This is a flag indicating whether 10a is user data or control data. The “PDU type” 311 indicates the type of the control data, and is indicated as STATUS-PDU 310a. The data portion provided between the “PDU type” 311 and the “PAD” 314 can include a plurality of information elements indicated by “SUFI” 313 as described later.

In FIG. 25, the delivery confirmation information element 410.
Is one of a plurality of information elements indicated by “SUFI” 313 in FIG. 24, and includes “Type = ACK” 411 and “LSN”.
412 and. The “LSN” 412 indicates the next value of the sequence number received continuously. However, when the same STATUS-PDU 310a includes the retransmission request information element 420 shown in FIG. 26, the “LSN” 412 indicates the value next to the upper limit value of the received sequence number.

In FIG. 26, a retransmission request information element 420
Is one of a plurality of information elements indicated by “SUFI” 313 in FIG. 24, and includes “Type = LIST” 421 and “LENGT”.
“H” 422 and the sequence number “SN ₁ ” 424-1 to “SN _LENGTH ” 42 at the beginning of the RLC-PDU 300a requesting retransmission.
4-L (hereinafter referred to as sequence number "SN" 424) and the number of RLC-PDUs 300a each following them "L"
₁ ”425-1 to“ L _{LENG TH} ”425-L (hereinafter, referred to as the subsequent number“ L ”425). "LENG
“TH” 422 is the sequence number “SN” 424 and RLC-PD.
It is the number of sets of the subsequent number “L” 425 of U300a. For example, when requesting retransmission of the RLC-PDU 300a with sequence numbers = 5, 6, and 7, SN = 5 and L = 2 are set.

Next, a conventional data packet retransmission control method will be described with reference to FIG. In the communication method being formulated by 3GPP, the periodic transmission interval TTI (TTI: Transmi
It is possible to collectively transmit a plurality of RLC-PDUs 300a for each ssion time interval). FIG. 22 shows an example in which four RLC-PDUs 300a are transmitted at each transmission interval TTI. Note that, in FIG. 22, the transmission interval TTI between the transmitting station and the receiving station is the same, and there is no difference in the timing of transmission and reception.

As shown in FIG. 23, the RLC-PDU 300a transmitted from the transmitting station to the receiving station has a sequence number 302 added to the data portion 308. The transmitting station can set "P" 303 in the header to request the receiving station to transmit the status notification message. For example, the transmitting station includes the end of data received from higher layers
RLC-PDU300a or RLC-PDU3 for which delivery confirmation has not been obtained
When the ratio of 00a exceeds a certain number, "P" 303 for RLC-PDU300a etc. to be transmitted after that
May be set.

[0012] The receiving station checks the sequence number 302 of the received RLC-PDU 300a and detects a sequence number 302 that is not received in order, that is, a missing sequence number 302, or in the header. When the RLC-PDU 300a in which "P" 303 is set is received, or whenever the periodic timer times out, the retransmission request information element 420 shown in FIG. 26 or the retransmission request information element 420 shown in FIG.
STATUS-PDU3 with delivery confirmation information element 410 shown in
10a is created, and the delivery confirmation and the resend request are notified to the transmitting station.

Specifically, in FIG. 22, the four RLC-PDUs (Seq.No = Seq.No =
If two RLC-PDUs (Seq.No = 1,2) out of 0,1,2,3) are missing, the receiving station performs protocol processing during the next transmission interval TTI-1. In 110a, the omission of Seq.No = 1, 2 is detected, and the following STATUS-PDU 310a is created. That is, in this STATUS-PDU 310a, FIG.
In FIG. 26, the value "4" next to the sequence number upper limit value "3" in the case where normal reception is possible is set in "LSN" 412, and RL that requests retransmission to "SN" 424.
The first sequence number "1" of C-PDU300 is set,
The subsequent number “1” is set in “L” 425. The receiving station transmits the STATUS-PDU 310a having the above-described content 200a during the next transmission interval TTI-2, and requests the transmitting station to retransmit.

In the protocol processing 100a executed during the next transmission interval TTI-3, the transmitting station performs STATUS-PDU3
In the period of the next transmission interval TTI-4, the missing of Seq.No = 1,2 is recognized from the retransmission request information element 420 of 10a, that is, the retransmission request is recognized for the RLC-PDU 300a of Seq.No = 1,2. The RLC-PDU 300a with Seq.No = 1 and 2 is retransmitted. On the other hand, the transmitting station transmits the Poll bit P to the RLC-PDU 300a of Seq.No = 11 which is transmitted during the transmission interval TTI-2.
When ("P" 303) is set, the receiving station detects the Poll bit P ("P" 303) in the protocol process 111a executed in the next transmission interval TTI-3.

At this point, the receiving station has requested retransmission.
Since the RLC-PDU 300a with Seq.No = 1 or 2 has not been received yet, the protocol processing 1 executed during the transmission interval TTI-3
In 11a, STATUS-PDU 310a having the following contents
To create. That is, in STATUS-PDU 310a, "L
"SN" 412 is set to the next value "12" of the sequence number upper limit value "11" when it is possible to receive by the period of the transmission interval TTI-3 in which the transmission request of the status notification message is recognized,
The leading sequence number “1” of the RLC-PDU 300a requesting retransmission is set in “SN” 424, and the subsequent number “1” is set in “L” 425. The receiving station is
During the TTI-4 period, the STATUS-PDU 310a having the content 201a as described above is transmitted, and the RLC-PD of Seq.No = 1,2 is transmitted.
Notify the transmitting station of the retransmission request for U300a.

In the protocol processing 101a executed during the next transmission interval TTI-5, the transmitting station sets Seq.No = 1,2.
The retransmission request for the RLC-PDU 300a is recognized, and the retransmission for the RLC-PDU 300a with Seq.No = 1, 2 is performed again in the next transmission interval TTI-6. Note that the transmitting station
RLC-PDU30 with Seq.No = 19 transmitted during TTI-5 period
When the Poll bit P (“P” 303) is set to 0a, the receiving station performs the Poll bit P in the protocol process 112a executed in the next transmission interval TTI-6.
("P" 303) is detected, and the transmission request of STATUS-PDU 310a is recognized.

[0017]

However, in the conventional data packet retransmission control method as described above, when the data retransmission and the retransmission request pass each other between the transmitting station and the receiving station, useless data is lost. There is a problem that retransmission may be performed. For example, the transmission interval TTI- in FIG.
3. In the period of TTI-4, the transmitting station recognizes the retransmission request and retransmits the data, but since the receiving station has not received the previously requested data, it again requests the retransmission STATUS-PDU.
310a is transmitted. In this way, there may be a case in which a data retransmission and a retransmission request pass each other between the transmitting station and the receiving station. In this case, conventionally, as shown in FIG.
RLC-PDU3 with Seq.No = 1,2 retransmitted during the transmission interval TTI-4
Even though 00a is correctly received, useless data retransmission may be performed in which the RLC-PDU 300a with Seq.No = 1, 2 is transmitted again during the transmission interval TTI-6.

The present invention has been made in view of the above, and it is possible to suppress unnecessary retransmission even when a data packet is retransmitted and a retransmission request is passed between the transmitting station and the receiving station. To obtain a data packet transmission device, a data packet reception device, a data packet transmission system and a data packet retransmission control method which are capable of performing retransmission control capable of preventing wasteful consumption of resources of a wireless line or a wired line. To aim.

[0019]

In order to achieve the above-mentioned object, a data packet transmitting apparatus according to the present invention is a data packet transmitted from a receiving side in the process of transmitting a data packet with a sequence number to the receiving side. When a status notification message including the upper limit value of the packet sequence number and information about the data packet in which the error is detected is received,
In a data packet transmission device that retransmits a data packet in which the error has been detected, when the status notification message is received from the receiving side, a judgment means for judging the presence or absence of a retransmission control table, and the judgment means When it is determined that a control table exists, the retransmission control table is referenced, and when the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table, the retransmission control table And a determination unit that determines the necessity of retransmission by extracting the difference between the information related to the data packets included in the status notification message.

According to the present invention, in the data packet transmitting device, when the status notification message is received from the receiving side, the judging means first judges whether or not the retransmission control table exists. As a result, if the retransmission control table exists, the determination means refers to the retransmission control table,
When the upper limit value of the sequence number included in the status notification message is less than the upper limit value of the sequence number included in the retransmission control table, the difference between the information on the data packets included in the retransmission control table and the status notification message is extracted, and the retransmission A decision is made. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet transmitting apparatus according to the next invention, in the above invention, when the judging means judges that the retransmission control table exists, the retransmission control table is referred to, and the sequence included in the status notification message is referred to. When the number upper limit value exceeds the sequence number upper limit value included in the retransmission control table, the delete control unit deletes the retransmission control table.

According to the present invention, in the data packet transmission device according to the above-mentioned invention, when the retransmission control table exists, the deleting unit refers to the retransmission control table and the upper limit of the sequence number included in the status notification message. When the value exceeds the upper limit value of the sequence number included in the retransmission control table, the retransmission control table is deleted.

In the data packet transmitting apparatus according to the next invention, the upper limit value of the sequence number of the received data packet and an error are detected from the receiving side in the process of transmitting the data packet with the sequence number to the receiving side. When receiving a status notification message including information about data packets, a status notification request message that requests the receiving side to send the status notification message in a data packet transmission device that retransmits the data packet in which the error is detected. , A request number adding means for adding the count value of the counter as a request number when the status notification request message is transmitted, and a retransmission control table of the retransmission control table when the status notification message is received. The judgment means for judging the presence or absence and the judgment means When it is determined that there is a retransmission control table, the retransmission control table is referenced, and when the status notification message and the sequence number upper limit value included in the retransmission control table match, the reason for transmitting the status notification message is When the status notification request message is received from the transmitting station and the request number included in the status notification message is less than or equal to the request number included in the retransmission control table, or the reason for sending the status notification message is a periodic timer. When the transmission reason is a timeout and the transmission reason does not match the transmission reason included in the retransmission control table, or the transmission reason of the status notification message is not the reception of the status notification request message from the transmitting station, and the cycle timer When it is not timed out, the retransmission control table and the It extracts a difference information about the data packet that is included in the status notification message, characterized by comprising a determination means for determining necessity of retransmissions.

According to the present invention, in the data packet transmitting device, the counter is incremented each time the status notification request message requesting the reception side to send the status notification message is transmitted, and the request number adding means sets the counter. The count value is added as a request number to the status notification request message transmitted above. When the status notification message is received, the determination means first determines whether or not there is a retransmission control table. As a result, when the retransmission control table exists, the retransmission control table is referred to by the determination means, and when the sequence number upper limit value included in the status notification message and the retransmission control table match, the status notification message is displayed. When the status notification request message is received from the transmitting station and the request number included in the status notification message is less than or equal to the request number included in the retransmission control table, or the status notification message is sent using the periodic timer. When the transmission reason is a timeout and the transmission reason does not match the transmission reason included in the retransmission control table, or when the transmission reason of the status notification message is not the reception of the status notification request message from the transmitting station and the timeout of the periodic timer , The data packet included in the retransmission control table and status notification message. Difference information is extracted about, necessity of retransmission is determined.
Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet transmitting apparatus according to the next invention, in the above invention, when the judging means judges that there is a retransmission control table, the retransmission control table is referred to, and the status notification message and the retransmission control are given. When the sequence number upper limit values included in the table match, when the request number included in the status notification message is larger than the request number included in the retransmission control table, or the reason for transmitting the status notification message Is a time-out of the periodic timer, and when the transmission reason matches the transmission reason included in the retransmission control table, there is provided deletion means for deleting the retransmission control table.

According to the present invention, in the data packet transmission device according to the above-mentioned invention, when the retransmission control table exists, the retransmission control table is referred to by the deleting means, and the status notification message and the retransmission control table are added. When the included sequence number upper limit values match, when the request number included in the status notification message is larger than the request number included in the retransmission control table, or the reason for sending the status notification message is that the periodic timer times out. Yes When the transmission reason matches the transmission reason included in the retransmission control table, the retransmission control table is deleted.

In the data packet transmitting device according to the next invention, in the above invention, when the judging means judges that the retransmission control table does not exist,
When it is decided to perform resending, the upper limit value of the sequence number of the data packet sent to the receiving side by the time the resending process execution decision is made, and if applicable, the request number and the reason for sending read from the status notification message and the data to resend Table setting means for creating the retransmission control table in which information about packets is set, and retransmission of the data packet based on information about the data packet to be retransmitted set in the retransmission control table after creating the retransmission control table. And a retransmitting means for carrying out.

According to the present invention, in the data packet transmission device according to the above-mentioned invention, when it is determined that the retransmission is to be performed when the retransmission control table does not exist,
In the table setting means, the upper limit value of the data packet sequence number transmitted to the receiving side by the time of determining the execution of the retransmission process and the request number, if applicable, the transmission reason read from the status notification message, and the information on the data packet to be retransmitted. Is set. After that, the retransmission means retransmits the data packet based on the information about the data packet to be retransmitted, which is set in the retransmission control table.

In the data packet receiving device according to the next invention, when an error is detected in the process of receiving the data packet with the sequence number from the transmitting side, the upper limit value of the sequence number of the data packet received by the transmitting side is set. In a data packet receiving device that transmits a status notification message including information on an error-detected data packet, the transmission cause of the status notification message is the reception of a status notification request message, or the detection of an error,
A transmission reason creating means for creating a transmission reason for whether the cycle timer has timed out, and a transmission reason created by the transmission reason creating means and the transmission reason when receiving the status notification request message when the status notification message is transmitted. When it is, it is characterized by comprising a transmission reason adding means for adding the request number read from the received status notification request message.

According to the present invention, in the data packet receiving device, when the transmission cause of the status notification message occurs,
The transmission reason creation means creates a transmission reason such as the reception of the status notification request message, the detection of an error, or the timeout of the cycle timer, and the transmission reason addition means creates the created transmission. When the reason and the transmission reason are the reception of the status notification request message, the request number read from the received status notification request message is added to the status notification message and transmitted to the data packet transmission device.

A data packet transmission system according to the next invention is a data packet receiving device for transmitting a status notification message including an upper limit value of a sequence number of a received data packet and information about a data packet in which an error is detected, A data packet transmission system including a data packet transmission device that retransmits a data packet in which an error is detected based on the status notification message received in the process of transmitting a data packet with a sequence number to the data packet reception device. At
The data packet transmission device, when receiving the status notification message, judges the presence or absence of a retransmission control table, and judges the retransmission control table if the judgment unit judges that the retransmission control table exists. When the upper limit value of the sequence number included in the status notification message is less than the upper limit value of the sequence number included in the retransmission control table, the difference between the information about the data packets included in the retransmission control table and the status notification message is referred to. And a determination unit that determines whether or not the packet is retransmitted.

According to the present invention, in the data packet transmission device in the data packet transmission system, when the status notification message is received, the determination means first determines whether or not the retransmission control table exists. As a result, when the retransmission control table exists, the retransmission control table is referred to by the determination means, and the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table, The difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet transmission system according to the next invention, in the above invention, the data packet transmission device refers to the retransmission control table when the determination means determines that the retransmission control table exists, and When the upper limit value of the sequence number included in the status notification message exceeds the upper limit value of the sequence number included in the retransmission control table, there is provided deletion means for deleting the retransmission control table.

According to the present invention, in the data packet transmission device in the data packet transmission system, when the retransmission control table exists, the deleting unit refers to the retransmission control table and the upper limit of the sequence number included in the status notification message. When the value exceeds the upper limit value of the sequence number included in the retransmission control table, the retransmission control table is deleted.

A data packet transmission system according to the next invention includes a data packet receiving device for transmitting a status notification message including an upper limit value of a sequence number of a received data packet and information on a data packet in which an error is detected, A data packet transmission system including: a data packet transmission device that retransmits a data packet whose error is detected based on the status notification message received in the process of transmitting a data packet with a sequence number to the data packet reception device. At
The data packet transmitting device counts a counter that counts the sequence number of a status notification request message that requests the data packet receiving device to send a status notification message, and a count value of the counter when transmitting the status notification request message. Request number adding means for adding as a request number, judging means for judging the presence / absence of a retransmission control table when the status notification message is received, and the judging means for judging whether or not the retransmission control table exists When the retransmission control table is referred to and the sequence number upper limit values included in the status notification message and the retransmission control table match, the reason for sending the status notification message is the reception of the status notification request message from the transmitting station. Yes Included in the status notification message When the request number is less than or equal to the request number included in the retransmission control table, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, Alternatively, when the reason for transmitting the status notification message is neither reception of the status notification request message from the transmitting station nor timeout of the periodic timer, the data packet included in the retransmission control table and the status notification message It is characterized by comprising a determining means for extracting a difference in information and determining whether or not retransmission is necessary.

According to the present invention, in the data packet transmission device in the data packet transmission system, the counter is incremented each time the status notification request message requesting the reception side to send the status notification message is transmitted, and the request number adding means is provided. The count value of the counter is added as a request number to the status notification request message to be transmitted. When the status notification message is received, the determination means first determines whether or not there is a retransmission control table. As a result, if the retransmission control table exists, the determination means refers to the retransmission control table,
If the sequence number upper limit values included in the status notification message and the retransmission control table match, the request number included in the status notification message is less than or equal to the request number included in the retransmission control table, or the status notification message is sent. When the reason is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, or the transmission reason of the status notification message is not the reception of the status notification request message from the transmitting station and the cyclic timer When it is not the time-out, the difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet transmission system according to the next invention, in the above invention, the data packet transmission device refers to the retransmission control table when the determination unit determines that the retransmission control table exists, When the sequence number upper limit value included in the status notification message and the retransmission control table match, when the request number included in the status notification message is larger than the request number included in the retransmission control table, or, When the transmission reason of the status notification message is a timeout of a periodic timer and the transmission reason matches the transmission reason included in the retransmission control table, a deletion unit for deleting the retransmission control table is provided.

According to the present invention, in the data packet transmission device in the data packet transmission system, when the retransmission control table exists, the deleting means refers to the retransmission control table, and the status notification message and the retransmission control table are displayed. If the included sequence number upper limit values match, the request number included in the status notification message is greater than the request number included in the retransmission control table, or the reason for sending the status notification message is that the periodic timer has timed out. When the transmission reason matches the transmission reason included in the retransmission control table, the retransmission control table is deleted.

In the data packet transmission system according to the next invention, in the above invention, when it is determined that the retransmission control table does not exist by the determination means, it is determined to perform retransmission, Up to the sequence number upper limit value of the data packet transmitted to the data packet receiving device and, if applicable, the request number and the transmission reason read from the status notification message and the information regarding the data packet to be transmitted And a retransmitting means for retransmitting the data packet based on the information about the data packet to be transmitted set in the retransmission control table after the retransmission control table is created. Characterize.

According to the present invention, in the data packet transmission device in the data packet transmission system, when the retransmission control table does not exist, when it is determined to perform the retransmission, the table setting means determines the retransmission processing execution. The upper limit value of the sequence number of the data packet transmitted to the receiving side by the time and the corresponding request number, the transmission reason read from the status notification message, and the information on the data packet to be transmitted are set if applicable. afterwards,
The retransmission means retransmits the data packet based on the information about the data packet to be transmitted set in the retransmission control table.

In the data packet transmission system according to the next invention, in the above invention, the data packet receiving device causes the status notification message to be transmitted by receiving a status notification request message or by detecting an error. Or a transmission reason creating means for creating a transmission reason indicating whether the cycle timer has timed out, a transmission reason created by the transmission reason creating means at the time of transmitting the status notification message, and the transmission reason is a status notification request message. When it is a reception, a transmission reason adding means for adding the request number read from the received status notification request message is provided.

According to the present invention, when the cause of transmission of the status notification message occurs in the data packet receiving device in the data packet transmission system, the transmission reason creating means detects the reception of the status notification request message or detects an error. Or a periodic timer timeout, a transmission reason is created, and when the created transmission reason and the transmission reason are reception of a status notification request message, the status notification received The request number read from the request message is added to the status notification message and transmitted to the data packet transmission device.

In the data packet retransmission control method according to the next invention, a data packet received from the data packet receiving device is transmitted while the data packet transmitting device is transmitting the data packet with the sequence number to the data packet receiving device. In the data packet retransmission control method, when a status notification message including an upper limit value of a sequence number and information about a data packet in which an error is detected is received, the data packet retransmission control method is performed. The device, when receiving the status notification message, a determination step of determining the presence or absence of a retransmission control table, and when the determination step determines that a retransmission control table exists, the retransmission control table is referred to, and Sequence number included in status notification message When the upper limit value is less than the sequence number upper limit value included in the retransmission control table, a determination step of determining whether retransmission is necessary by extracting a difference in information about data packets included in the retransmission control table and the status notification message It is characterized by including and.

According to the present invention, in the data packet transmitting device, when the status notification message is received from the receiving side, the existence of the retransmission control table is first judged in the judging step. As a result, when the retransmission control table exists, the retransmission control table is referenced in the determination step, and the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table. The difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet retransmission control method according to the next invention, in the above invention, when the determination step determines that a retransmission control table exists, the retransmission control table is referred to and included in the status notification message. When the sequence number upper limit value exceeds the sequence number upper limit value included in the retransmission control table, a deletion step of deleting the retransmission control table is included.

According to the present invention, in the data packet transmission device, when the retransmission control table exists, the retransmission control table is referred to in the deleting step, and the upper limit value of the sequence number included in the status notification message is the retransmission control table. Is exceeded, the retransmission control table is deleted.

In the data packet retransmission control method according to the next invention, the data packet received from the data packet receiving device while the data packet transmitting device is transmitting the data packet with the sequence number to the data packet receiving device. In the data packet retransmission control method, when the status notification message including the upper limit value of the sequence number of and the information about the data packet in which the error is detected is retransmitted, the data packet in which the error is detected is retransmitted. The transmitting device adds a request number to the state notification request message by transmitting the count value of a counter for counting the sequence number of the state notification request message requesting the data packet receiving device to transmit the state notification message as a request number. Process and the data When the status notification message is received from the packet receiving device, a determination step of determining the presence / absence of a retransmission control table and a reference to the retransmission control table when the determination step determines that a retransmission control table exists, When the sequence number upper limit values included in the status notification message and the retransmission control table match, the reason for transmitting the status notification message is the reception of the status notification request message from the transmitting station, and the status notification message includes the status notification message. When the request number is less than or equal to the request number included in the retransmission control table, or the reason for transmitting the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table. When, or
When the reason for transmitting the status notification message is neither the reception of the status notification request message from the transmitting station nor the timeout of the periodic timer, the information about the data packet included in the retransmission control table and the status notification message A determination step of extracting a difference and determining whether or not retransmission is necessary is included.

According to the present invention, in the data packet transmitting device, the counter is incremented each time the status notification request message requesting the data packet receiving device to send the status notification message is transmitted, and the counter is incremented in the request number adding step. The count value of the counter is added as a request number to the status notification request message to be transmitted. When the status notification message is received, the presence or absence of the retransmission control table is first determined in the determination step. As a result, if the retransmission control table exists, the retransmission control table is referenced in the determination step, and if the sequence number upper limit value included in the status notification message and the retransmission control table match, the status notification message is displayed. When the request number included in is less than or equal to the request number included in the retransmission control table, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, Alternatively, when the reason for transmitting the status notification message is neither reception of the status notification request message from the transmitting station nor timeout of the periodic timer, the difference in information regarding the data packets included in the retransmission control table and the status notification message is extracted. Then, the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done.

In the data packet retransmission control method according to the next invention, in the above invention, when the determination step determines that a retransmission control table exists, the retransmission control table is referred to, and the status notification message and the retransmission are sent. When the sequence number upper limit value included in the control table matches, when the request number included in the status notification message is larger than the request number included in the retransmission control table, or the status notification message is transmitted. When the reason is the timeout of the periodic timer and the transmission reason matches the transmission reason included in the retransmission control table, a deletion step of deleting the retransmission control table is included.

According to the present invention, in the data packet transmission device, when the retransmission control table exists, the retransmission control table is referred to in the deleting step, and the sequence number included in the status notification message and the retransmission control table. When the upper limit values match, when the request number included in the status notification message is greater than the request number included in the retransmission control table, or the reason for sending the status notification message is a periodic timer timeout and When the transmission reason included in the control table matches, the retransmission control table is deleted.

In the data packet retransmission control method according to the next invention, in the above invention, when it is determined in the determination step that the retransmission control table does not exist, the retransmission processing execution determination is made when the retransmission is determined to be performed. By the time, the upper limit value of the sequence number of the data packet transmitted to the data packet receiving device and, if applicable, the request number, the retransmission reason set from the status notification message, and the information about the data packet to be transmitted, the retransmission Including a table setting step of creating a control table, and a resending step of, after creating the resend control table, resending the data packet based on information about the data packet to be sent set in the resend control table Is characterized by.

According to the present invention, in the data packet transmission device, when the retransmission control table does not exist,
When it is decided to retransmit, in the table setting step, it is read from the upper limit value of the sequence number of the data packet transmitted to the receiving side by the time of deciding the retransmission process execution and, if applicable, the request number and the status notification message. Information about the transmission reason and the data packet to be transmitted is set. Then, in the retransmission step, the data packet is retransmitted based on the information about the data packet to be transmitted set in the retransmission control table.

In the data packet retransmission control method according to the next invention, in the above invention, the data packet receiving device determines whether the cause of transmission of the status notification message is the reception of the status notification request message or an error detection. Or a transmission reason creation step of creating a transmission reason of whether the periodic timer has timed out, and when sending the status notification message, the transmission reason created by the transmission reason creation step and the transmission reason are status notifications. When the request message is received, a transmission reason adding step of adding the request number read from the received status notification request message is included.

According to the present invention, when the cause of transmission of the status notification message occurs in the data packet receiving device, in the transmission reason creating step, whether the status notification request message is received, whether an error is detected, or the cycle is sent. A transmission reason indicating whether the timer has timed out is created, and when the created transmission reason and the transmission reason concerned are the reception of the status notification request message in the transmission reason addition step, the status notification request message is read from the received status notification request message. The request number and the status notification message are added to the status notification message and transmitted to the data packet transmission device.

A data packet transmission device according to the next invention multicasts the same data packet with a sequence number to a plurality of reception devices, and the upper limit value and the error of the sequence number of the multicast data packet normally received from each reception device. When a status notification message including information about the detected multicast data packet is received, in the data packet transmission device that retransmits the multicast data packet in which the error is detected, the sequence number included in the status notification message Based on the content of the corresponding sequence number in the retransmission control table based on the above, when the retransmission is not yet performed, the retransmission execution means for performing the retransmission for the multicast data packet of the sequence number, and the multicast for which the retransmission was performed Characterized in that the association with the sequence number of the data packet the upper limit of the transmitted sequence number at the time of performing the retransmission and a table setting means for setting the retransmission control table.

According to the present invention, in the data packet transmitting device for transmitting the data packet by multicast, when the status notification message is received, the corresponding sequence number in the retransmission control table is based on the sequence number included in the status notification message. Content is referenced,
When the retransmission has not been performed yet, the retransmission execution means retransmits the multicast data packet having the sequence number. Then, the table setting means sets, in the retransmission control table, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed in association with the sequence number of the retransmitted multicast data packet. That is, in the retransmission control table, it is initially displayed that the multicast data packet of the sequence number has not been retransmitted, but when the retransmission is performed,
The implementation status of the retransmission is set, and it is displayed that the retransmission has been completed.

In the data packet transmitting apparatus according to the next invention, in the above invention, when the content related to the corresponding sequence number in the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted. The upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is the upper limit value of the sequence number already transmitted at the time of performing the retransmission set in the retransmission control table. It is characterized in that it is provided with a re-execution means for re-transmitting the multicast data packet having the sequence number only when it is larger.

According to the present invention, in the data packet transmitting device for transmitting a data packet by multicasting, in the above-mentioned invention, the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message. When the contents have been retransmitted, the upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is set at the time of performing the retransmission set in the retransmission control table. Only when it is larger than the upper limit value of the transmitted sequence number, the retransmitting means retransmits the multicast data packet of the sequence number.

In the data packet transmitting apparatus according to the next invention, in the above invention, when the transmission reason contained in the status notification message is an unconditional retransmission request, the status is remarked regardless of the contents of the retransmission control table. It is characterized in that it is provided with a retransmitting means for retransmitting the multicast data packet having the sequence number included in the notification message.

According to the present invention, in the data packet transmitting device for transmitting a data packet by multicast, in the above invention, when the transmission reason included in the status notification message is an unconditional retransmission request, a retransmission execution means is provided. Then, regardless of the content of the retransmission control table, the retransmission is performed for the multicast data packet having the sequence number included in the status notification message.

In the data packet transmitting apparatus according to the next invention, in the above invention, when a new data packet having the same number as the retransmitted sequence number in the retransmission control table is transmitted, the contents relating to the sequence number are retransmitted. It is characterized in that it is provided with a table reset means for performing processing for returning to the non-implementation.

According to the present invention, in the data packet transmitting device for transmitting a data packet by multicasting, in the above invention, the table resetting means causes the new data having the same sequence number as the retransmitted sequence number in the retransmission control table. When the packet is transmitted, a process for returning the content related to the sequence number to the state where the retransmission is not performed is performed.

A data packet receiving apparatus according to the next invention, when a missing sequence number or a data error is detected in the process of receiving a multicast data packet with a sequence number from the transmitting apparatus, receives the data from the transmitting apparatus. In a data packet receiving device that transmits a status notification message including the upper limit value of the sequence number of the multicast data packet and information about the multicast data packet in which the error is detected, the status notification message to be transmitted is unconditionally requested to retransmit. It is characterized by comprising a transmission reason creating means for including a transmission reason to perform and a transmission reason for requesting retransmission which is not unconditional.

According to the present invention, in each data packet receiving device for receiving a data packet by multicast,
When transmitting the status notification message, the transmission reason creating means may include the transmission reason for unconditionally requesting retransmission and the transmission reason for requesting unconditional retransmission in the status notification message to be transmitted. Be seen.

The data packet transmission system according to the next invention receives a plurality of data packets for transmitting a status notification message including the upper limit value of the sequence number of the received multicast data packet and information on the multicast data packet in which an error is detected. When the same data packet with a sequence number is multicast to a device and the plurality of data packet receiving devices and the status notification message is received from the plurality of data packet receiving devices, the multicast data packet in which the error is detected is retransmitted. In the data packet transmission system including a data packet transmission device for implementing the above, the data packet transmission device is configured to correspond to a sequence in the retransmission control table based on the sequence number included in the status notification message. The content of the number is referred to, and when the retransmission is not yet performed, the retransmission is performed by associating the retransmission performing means for performing the retransmission of the multicast data packet of the sequence number with the sequence number of the multicast data packet for which the retransmission is performed. Table setting means for setting the upper limit value of the sequence numbers already transmitted at the time of execution in the retransmission control table.

According to the present invention, in the data packet transmission device in the data packet transmission system for transmitting / receiving the data packet by multicast, when the status notification message is received, the retransmission control is performed based on the sequence number included in the status notification message. When the content related to the corresponding sequence number in the table is referred to and the retransmission is not yet performed, the retransmission execution means performs the retransmission for the multicast data packet of the sequence number.
Then, the table setting means sets, in the retransmission control table, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed in association with the sequence number of the retransmitted multicast data packet. In other words, the retransmission control table initially displays that the multicast data packet of the sequence number has not been retransmitted, but when the retransmission is performed, the retransmission implementation status is set and the retransmission has been performed. Is displayed.

In the data packet transmission system according to the next invention, in the above invention, the data packet transmission device relates to the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message. Is already performed, the upper limit value of the sequence number of the multicast data packet normally received by the receiving apparatus included in the status notification message is set at the retransmission control table and is transmitted when the retransmission is performed. The present invention is characterized in that a retransmitting means for retransmitting the multicast data packet having the sequence number is provided only when the sequence number is larger than the upper limit value of the already-completed sequence number.

According to the present invention, in the data packet transmission device in the data packet transmission system for transmitting and receiving the data packet by multicast, in the above invention, the retransmission control table referred to based on the sequence number included in the status notification message. When the content related to the corresponding sequence number has been retransmitted, the upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is set in the retransmission control table. Only when it is larger than the upper limit value of the transmitted sequence number at the time of performing the retransmission, the retransmission execution unit retransmits the multicast data packet of the sequence number.

[0069] In the data packet transmission system according to the next invention, in the above invention, the data packet transmission device stores the data in the retransmission control table when the transmission reason included in the status notification message is an unconditional retransmission request. Regardless of the content, it is characterized by including a re-execution means for re-transmitting the multicast data packet having the sequence number included in the status notification message.

According to the present invention, in the data packet transmission device in the data packet transmission system for transmitting and receiving data packets by multicast, in the above invention, when the transmission reason included in the status notification message is an unconditional retransmission request. In this case, the retransmitting means retransmits the multicast data packet having the sequence number included in the status notification message regardless of the contents of the retransmission control table.

In the data packet transmission system according to the next invention, in the above invention, the data packet transmission device is configured such that, when a new data packet having the same number as the sequence number already retransmitted in the retransmission control table is transmitted, It is characterized in that it is provided with a table reset means for performing a process for returning the contents related to the sequence number to the state where the retransmission is not executed.

According to the present invention, in the data packet transmitting device in the data packet transmitting system for transmitting and receiving the data packet by multicast, in the above invention, the table resetting means causes the sequence number of the retransmission performed in the retransmission control table. When a new data packet having the same number as is transmitted, a process of returning the content related to the sequence number to the state where retransmission is not performed is performed.

In the data packet transmission system according to the next invention, in the above invention, the data packet receiving device unconditionally requests retransmission for the status notification message to be transmitted, and requests unrequired retransmission. And a transmission reason creating means for including the transmission reason.

According to the present invention, in the data packet receiving device in the data packet transmission system for transmitting / receiving the data packet by multicasting, in the above invention, when the status notification message is transmitted, the transmission reason creating means provides The status notification message to be transmitted includes a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting non-conditional retransmission.

In the data packet retransmission control method according to the next invention, the data packet transmitting device multicasts the same data packet with a sequence number to a plurality of data packet receiving devices, and the data packet is normally received from the data packet receiving device. A data packet retransmission control method for performing retransmission of a multicast data packet in which an error is detected, when a status notification message including an upper limit value of a sequence number of a data packet and information regarding a multicast data packet in which an error is detected is received. The data packet transmission device refers to the content regarding the corresponding sequence number in the retransmission control table based on the sequence number included in the status notification message, and when the retransmission is not performed, the multi-packet of the sequence number is transmitted. A re-execution step of re-transmitting the last data packet, and an upper limit value of the sequence number already transmitted at the time of the re-transmission in association with the sequence number of the re-transmitted multicast data packet. And a table setting step for setting.

According to the present invention, when a data packet transmitting / receiving device receives a status notification message requesting retransmission when transmitting / receiving a data packet by multicasting, based on the sequence number included in the status notification message. When the content regarding the corresponding sequence number in the retransmission control table is referred to and the retransmission has not been performed, the retransmission is performed for the multicast data packet of the sequence number in the retransmission step. Then, in the table setting step, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed is set in the retransmission control table in association with the sequence number of the retransmitted multicast data packet. That is, although the retransmission control table initially displays that the multicast data packet of the sequence number has not been retransmitted yet,
When a resend is performed, the status of that resend is set,
It is displayed that the retransmission has been completed.

In the data packet retransmission control method according to the next invention, in the above invention, the data packet transmission device relates to the corresponding sequence number in the retransmission control table referred to based on the sequence number included in the status notification message. When the contents have been retransmitted, the upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is set at the time of performing the retransmission set in the retransmission control table. It is characterized in that it includes a retransmission execution step of performing retransmission for the multicast data packet of the sequence number only when it is larger than the upper limit value of the transmitted sequence number.

According to this invention, in the above invention,
In the data packet transmission device, when the status notification message requesting retransmission is received, when the content related to the corresponding sequence number in the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted. The upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is the upper limit value of the sequence number already transmitted at the time of performing the retransmission set in the retransmission control table. Only when it is larger than the above, the retransmission is performed for the multicast data packet of the sequence number in the retransmission execution step.

In the data packet retransmission control method according to the next invention, in the above invention, the data packet transmission device is configured to transmit the retransmission control table when the transmission reason included in the status notification message is an unconditional retransmission request. Irrespective of the contents of the above item, the present invention is characterized by including a retransmission execution step of performing retransmission for the multicast data packet having the sequence number included in the status notification message.

According to this invention, in the above invention,
In the data packet transmission device, when the status notification message requesting retransmission is received, the transmission reason included in the status notification message is examined, and if the transmission reason is an unconditional retransmission request, in the retransmission execution step. Regardless of the content of the retransmission control table, the retransmission is performed for the multicast data packet having the sequence number included in the status notification message.

In the data packet retransmission control method according to the next invention, in the above invention, the data packet transmission device transmits a new data packet having the same number as the sequence number already retransmitted in the retransmission control table. , And a table reset step of performing a process of returning the content related to the sequence number to a state where retransmission is not yet performed.

According to this invention, in the above invention,
In the data packet transmission device, in the table reset step, when a new data packet having the same number as the already retransmitted sequence number in the retransmission control table is transmitted, processing for returning the content related to the sequence number to the non-retransmitted state is performed. Be seen.

In the data packet retransmission control method according to the next invention, in the above invention, the data packet receiving device may unconditionally request a retransmission for the status notification message to be transmitted and perform a non-conditional retransmission. It is characterized by including a step of including a request transmission reason.

According to the present invention, each data packet receiving device that receives a data packet by multicasting,
When sending a status notification message, in the sending reason creation step, the status notification message to be sent may include a sending reason for unconditionally requesting retransmission and a sending reason for requesting unconditional retransmission. Be seen.

[0085]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a data packet transmitting device, a data packet receiving device, a data packet transmission system and a data packet retransmission control method according to the present invention will be described in detail below with reference to the accompanying drawings. To do.

Embodiment 1. 1 is a block diagram showing the configuration of a data packet transmission system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the transmitting station shown in FIG. FIG. 3 is a diagram showing a format example of a data packet transmitted by the transmitting station shown in FIG. FIG. 4 is a diagram showing a configuration example of a retransmission control table provided for retransmission control by the transmitting station shown in FIG. Figure 5
2 is a block diagram showing a configuration of a receiving station shown in FIG. 1. FIG. Figure 6
FIG. 3 is a diagram showing a format example of a status notification message transmitted by the receiving station shown in FIG. 1 in response to reception of a status notification request message. FIG. 7 is a diagram showing a format example of a status notification message transmitted by the receiving station shown in FIG. 1 upon error detection or timeout of a periodic timer. In FIGS. 3, 6, and 7, the same number or the corresponding number is given to the same portion as the conventional example (FIGS. 23 and 24).

In FIG. 1, a transmitting station 1 which is a data packet transmitting device and a receiving station 2 which is a data packet receiving device.
Are connected via a transmission path (wireless transmission path or wired transmission path) 3. The transmitting station 1 sequentially transmits data packets (RLC-PDU) generated by interleaving a predetermined number of new PDUs (data packets with sequence numbers) sent from the upper layer to the transmission path 3. At this time, the transmitting station 1 can add the Poll bit to the data packet with the sequence number to be transmitted. The data packet with the sequence number added with the Poll bit is referred to as a status notification request message requesting the receiving station 2 to send a status notification message (STATUS-PDU).

The Poll bit may be set in a data packet to be transmitted thereafter when the ratio of data packets for which delivery confirmation has not been taken exceeds a certain number. When it is necessary to indicate the end of the data packet received from the higher layer, it may be set to the data packet including the end. The receiving station 2 deinterleaves the data packet (RLC-PDU) fetched from the transmission path 3 to restore the data packet with the sequence number, and processes the received data while confirming the continuity of the sequence number and the CRC. To execute. At this time,
The receiving station 2 receives the transmitted data packet (RLC-PDU)
The reception status and the like are notified to the transmitting station 1 using a status notification message (STATUS-PDU).

The status notification message (STATUS-PDU) may be created and transmitted when the status notification request message is sent from the transmitting station 1, or may be spontaneously created and transmitted by the receiving station 2. . The spontaneous transmission is performed when an error such as a missing sequence number or a CRC error is detected, and when the cycle timer times out. The status notification message (STATUS-PDU) created and transmitted at the time of error detection includes the sequence number of the data packet in error and the upper limit value of the sequence number that was successfully received. The status notification message (STATUS-PDU) created and sent when the status notification request message is received or timed out has the same contents as above if error detection is performed, but the sequence number continuity If the CRC and CRC can be confirmed correctly, that effect (ACK) and the upper limit value of the sequence number of the data packet that can be normally received are included.

When the transmitting station 1 receives from the receiving station 2 a status notification message (STATUS-PDU) containing the sequence number of an erroneous data packet, it recognizes it as a resend request and resends it. In the first mode, the transmitting station 1 has the configuration shown in FIG. 2 and the receiving station 2 has the configuration shown in FIG. 5 so that the retransmission is performed under certain conditions. In the following description, detection of missing sequence numbers is taken as an example of error detection.

FIG. 2 is a block diagram mainly showing a configuration of a part related to retransmission control of the transmitting station. In FIG. 2, the transmission station 1 includes a transmission PDU generation unit 11, a transmission unit 12, and a Poll C.
It includes an ounter 13, a resending determination unit 14, a resending control table 15, a message reception processing unit 16, and a receiving unit 17.

The Poll Counter 13 is a counter that is incremented each time the Poll bit is set.
The count value of the Poll Counter 13 is output to the transmission PDU generation unit 11 and the retransmission determination unit 14 as a request number. The transmission PDU generation unit 11 uses the new PDU from the upper layer.
Data packets generated by interleaving a predetermined number of (transmission data packets with sequence numbers) (RL
C-PDU) is sequentially transmitted to the transmission path 3 via the transmission unit 12. At this time, when there is a Poll bit setting input, the transmission PDU generation unit 11 attaches the Poll bit to the corresponding data packet and also attaches the count value of the Poll Counter 13 to the data packet as a request number. In addition, the transmission PDU generation unit 11 includes the retransmission determination unit 1
When a retransmission PDU (retransmission data packet with a sequence number) is input from 4, a data packet (RLC-PDU) including the retransmission PDU and a new PDU is generated.

The status notification message (STATUS-PDU) sent from the receiving station 2 is input to the message reception processing unit 16 via the receiving unit 17. The message reception processing unit 16 receives the status notification message (STATUS-PD
U) is transmitted to the retransmission judgment unit 14, and if the status notification message (STATUS-PDU) includes the retransmission request information element 420 shown in FIG. 26, the information set in it (the first sequence (Number, subsequent number, set number) and save. The stored information is used by the resend determination unit 14.

Upon receiving the status notification message (STATUS-PDU) from the message reception processing unit 16, the resend determination unit 14 first checks the existence of the resend control table 15.
As a result, if the retransmission control table 15 does not exist, the retransmission determination unit 14 determines that the retransmission processing is necessary, and the retransmission number such as the upper limit value of the sequence number of the data packet transmitted by the determination time is transmitted as described later. It is set in the control table 15 and the retransmitted PDU is output to the transmitted PDU generation unit 11.

On the other hand, when the retransmission control table 15 exists, the retransmission judgment unit 14 refers to the retransmission control table 15, and basically, the received status notification message (ST
The upper limit value of the sequence number included in the ATUS-PDU) is compared with the upper limit value of the sequence number set in the retransmission control table 15. Then, if the upper limit value of the sequence number included in the received status notification message (STATUS-PDU) does not exceed the upper limit value of the sequence number set in the retransmission control table 15, the received status notification message (STATUS-PDU PDU) and the information about the data packet set in the retransmission control table 15 are extracted to determine whether or not the retransmission is necessary.
There are various specific judgment conditions, which will be described later.

At this time, since one or more retransmission control tables 15 are set, the retransmission determination section 14 performs the above determination operation for each retransmission control table 15. The retransmission control table 15 which is no longer needed in the process is deleted, and when the retransmission control table 15 is needed, the additional setting operation is performed.

Before describing the retransmission control table 15, the format of the data packet transmitted by the transmitting station 1 will be described. In FIG. 3, a “Poll Counter” 306 is added to a data packet (hereinafter sometimes simply referred to as “RLC-PDU”) 300 in the first embodiment. “P” is displayed in “Poll Counter” 306.
The count value of the Poll Counter 13 that is incremented by setting the Poll bit to 303 is set.
That is, the Poll Counter 13 is counting the sequence number of the status notification request message. Others are the same as the conventional example (FIG. 23). In addition, "P" 3
RLC-PDU300 with Poll bit set to 03
Is a status notification request message. In the following explanation,
The notation “P” 303 means that the Poll bit is set.

Now, in the retransmission control table 15, as shown in FIG. 4, "Poll Counter" 401, "Cause" 40
2, "VT (M)" 403, "LENGTH" 404, "SN
₁ "405-1～" SN _LENGTH "405-L (hereinafter simply" SN "405, referred to as as" SN ")," L ₁ "
406-1 to "L _LENGTH " 406-L (hereinafter simply "L")
406, described as “L”, etc.) is set. "Poll Counter" 401 contains Poll Cou
The count value of the nter 13, that is, the request number transmitted to the receiving station 2 is set. When this setting is performed, retransmission is then performed. Therefore, "Poll Counter" 4
The count value of the Poll Counter 13 at the time of retransmission decision is set to 01.

In “Cause” 402, the transmission reason “Cause” extracted from the received status notification message is set. In “VT (M)” 403, the upper limit value of the sequence number of the data packet transmitted up to the retransmission decision point is set. The "SN" 405 is set with the leading sequence number of the retransmitted data packet. In “L” 406, the number of data packets following the data packet of “SN” 405 consecutively (hereinafter referred to as “subsequent number”) is set. In “LENGTH” 404, the number of pairs of the leading sequence number “SN” 405 and the subsequent number “L” 406 is set.

Next, the receiving station 2 will be described. Figure 5
FIG. 3 is a block diagram mainly showing a configuration of a part related to retransmission control of the receiving station 2. The receiving station 2, as shown in FIG.
The receiver 21, the sequence monitor 22, the period timer 23, the transmission reason generator 24, the status notification message generator 25, and the transmitter 26 are provided.

The receiving unit 21 deinterleaves the data packets (RLC-PDU) sent from the transmitting station 1, transmits the individual data packets to the sequence monitoring unit 22 in the receiving processing system, and also deinterleaves them. It is checked whether or not the data packet with "P" 303, that is, the status notification request message, is included in each of the individual data packets. When the status notification request message is detected, the message request (“P” 3
03) and request number (Poll Counter 306),
While outputting them to the status notification message creation unit 25, it outputs a message request (“P” 303) to the transmission reason creation unit 24.

The sequence monitoring unit 22 checks the continuity of sequence numbers in continuously received data packets and, when detecting a missing sequence number, outputs the missing sequence number to the state notification message creating unit 25 and The transmission reason creation unit 24 is notified of the fact that The cycle timer 23 measures an interval of, for example, 5 seconds, and notifies the transmission reason creating unit 24 and the status notification message creating unit 25 that the time-out has occurred each time the time is measured.

The transmission reason creation unit 24 creates the reason that caused the status notification message creation unit 25 to create and send the status notification message (STATUS-PDU), that is, the reason for sending, and sends it to the status notification message creation unit 25. Output. That is, when the transmission reason creation unit 24 receives the message request (“P” 303) from the reception unit 21, the transmission reason ““ P ”is transmitted.
“Reception of 303” is created, and the status notification message creation unit 2 is created.
Output to 5. The transmission reason creation unit 24 uses the cycle timer 23.
When the timeout is received from, the transmission reason “period timer timeout” is created and output to the status notification message creating unit 25. When the transmission reason creation unit 24 receives the omission detection from the sequence monitoring unit 22, the transmission reason creation unit 24 creates the transmission reason “loose detection of the sequence number 302” and outputs it to the status notification message creation unit 25.

The status notification message creating section 25 uses the status notification message shown in FIG. 6 and FIG.
-PDU ") may be created and transmitted to the transmission station 1 via the transmission unit 26 to the transmission line 3. As shown in FIGS. 6 and 7, in the first embodiment, a transmission reason “Cause” 315 is added. Reason for sending "Cause"
The transmission reason received from the transmission reason creating unit 24 is set in 315. The STATUS-PDU 310-1 shown in FIG.
Since the message is sent by the receiving station 2 when the Poll bit is received, "Cause" 315 is set to "Receive" P "303." STAT shown in FIG.
Since the US-PDU 310-2 is a message to be transmitted by the omission detection in the sequence monitoring unit 22 and the timeout of the cycle timer 23, the transmission reason “Cause” 315 is
“Detection of missing sequence number 302” or “cycle timer timeout” is set.

Then, as shown in FIG.
STATUS-PDU 310 transmitted by receiving the all bit
In -1, "Poll Counter" 316 and "R" 312 are added. In the "Poll Counter" 316, the request number (Poll Counter 306) received from the receiving unit 21 is set as it is. “R” 312 is a reserved bit.

6 and 7, the others are the same as the conventional STATUS-PDU 310a (FIG. 24). That is, the delivery confirmation information element 410 shown in FIG.
The retransmission request information element 420 shown in FIG. 26 is similarly applied to this embodiment. In other words, the status notification message creation unit 25 sets the delivery confirmation information element 410 to “LS
N ”412 is set. If there is a data packet requesting retransmission, “SN” 4 is set in the retransmission request information element 420.
24, “L” 425, and “LENGTH” 422 are set.

Next, with reference to FIG. 8, a data packet retransmission control operation executed in the data packet transmission system configured as described above will be described (operation example 1). 8 is a sequence diagram for explaining the data packet retransmission control operation. In the communication method being formulated by 3GPP, the periodic transmission interval TTI (TTI: Transmission Tim
It is possible to collectively transmit a plurality of RLC-PDUs 300 for each eInterval). FIG. 8 shows an example in which four RLC-PDUs 300 are transmitted at each transmission interval TTI.
Further, in FIG. 8, the transmission interval TTI between the transmitting station and the receiving station is the same, and there is no difference in the timing of transmission and reception.

In FIG. 8, the four RLC-PDUs (Seq.No = 0,1,2,) transmitted by the transmitting station during the period of the transmission interval TTI-0.
If two RLC-PDUs (Seq.No = 1, 2) out of 3) are missing, the receiving station performs RLC in the protocol process 110-1 executed in the next transmission interval TTI-1. -A missing seq.No = 1,2 was detected in the PDU reception process, and the following STATUS-PDU
(200-1) 310-2 is created. Ie this
In STATUS-PDU (200-1) 310-2, FIGS.
In FIG. 5 and FIG. 26, the transmission reason “Cause” 315 is set to “Miss” indicating “missing detection of the transmission sequence number 302”, and the “LSN” 412 is assumed to be able to receive normally. Is set to a value "4" subsequent to "," and RNC-PDU3 for requesting retransmission to "SN" 424
The first sequence number "00" of 00 is set and "L" 4
The subsequent number “1” is set in 25.

The receiving station receives the STATUS-PDU (200-
1) 310-2 is transmitted and a retransmission request is made to the transmitting station. From the retransmission request information element 420 of the received STATUS-PDU (200-1) 310-2 in the STATUS-PDU receiving process in the protocol process 100-1 executed in the next transmission interval TTI-3, the transmitting station Recognizing the missing Seq.No = 1,2,
That is, the retransmission request for the RLC-PDU 300 with Seq.No = 1, 2 is recognized. Then, in this example, the retransmission control table 1
5 does not exist, the retransmission control table 15 is set as follows.

That is, in FIG. 4, "Cause" 40
2 indicates the reason for sending the received STATUS-PDU 310-2 "Ca
The transmission reason “Miss” read from “use” 315 is set. The “VT (M)” 403 contains the RLC transmitted to the receiving station by the period of the transmission interval TTI-3 determined to be retransmitted.
-The upper limit value "15" of the sequence number of the PDU 300 is set. In the "SN" 405, the first sequence number "1" fetched from the STATUS-PDU 310-2 is set.
In “L” 406, the subsequent number “1” fetched from STATUS-PDU 310-2 is set. The number of sets “1” is set in “LENGTH” 404. As described below, Seq.No.
In the RLC-PDU 300 of = 11, the Poll bit P1 is set and the count value of the “Poll Counter” 306 is “1”. , The transmission interval TTI-3), the count value “1” of the “Poll Counter” 306 is set.

The transmitting station retransmits the RLC-PDU 300 with Seq.No = 1, 2 during the next transmission interval TTI-4. During the transmission interval TTI-4, Seq.No = 1,
2 RLC-PDU300 of 2 and Seq. Which is the original transmission data.
Two RLC-PDUs 300 of No = 16,17 will be transmitted.

On the other hand, in the transmitting station, Poll is performed in the RLC-PDU300 of Seq.No = 11 which is transmitted during the transmission interval TTI-2.
When bit P1 (“P” 303) is set, Poll
Counter 13 is incremented, and the count value "1" is used as the request number and "Poll Counte" of RLC-PDU300.
r "306. That is, in the period of the transmission interval TTI-2, the status notification request and the RLC-PDU 300 with the request number are transmitted to the receiving station.

The receiving station detects the Poll bit P1 ("P" 303) in the RLC-PDU receiving process in the protocol process 111-1 executed during the next transmission interval TTI-3, and detects the status notification message ( Recognize the transmission request of STATUS-PDU 310-1). However, at this time point, the receiving station has not yet received the RLC-PDU 300 of Seq.No = 1, 2 that requested the retransmission. Therefore, the receiving station receives the status notification message (STATUS-PDU (201-1) 310-
Create 1).

That is, the STATUS created in the protocol processing 111-1 executed during the transmission interval TTI-3.
-In PDU (201-1) 310-1, transmission reason "Cause" 315 is "Poll" in FIGS.
“P1” indicating “reception of bit P1 (“ P ”303)” is set, and “Poll Counter” 306 of the status notification request message received in the request number (“Poll Counter” 316).
The value "1" read from is set and "LSN" 412
The transmission interval TT at which the request to send the status notification message was recognized
The value "12" next to the sequence number upper limit value "11" when the signal is received by the period of I-3 is set, and "SN" 4
The leading sequence number “1” of the RLC-PDU 300 requesting retransmission is set in 24, and the subsequent number “1” is set in “L” 425.

The receiving station receives the STATUS-PDU (201-201) having the above contents during the next transmission interval TTI-4.
1) 310-1 is transmitted and RLC-PDU300 of Seq.No = 1,2
The re-sending request is sent again to the transmitting station. The transmitting station responds to the received STATUS-PDU 310-1 by the protocol processing 101 to be executed in the period of the next transmission interval TTI-5.
In -1, when the retransmission request for the RLC-PDU 300 of Seq.No = 1, 2 is recognized, the existence of the retransmission control table 15 is confirmed and the retransmission control table 15 is referred to. Judge whether or not.

First, the value obtained by subtracting "-1" from "LSN" included in STATUS-PDU 310-1 and retransmission control table 15
The magnitude comparison with the “VT (M)” 403 set to LSN-1 = 11, and "VT (M)" 403
Is smaller than the value "15". By this, the transmitting station
The STATUS-PDU 310-1 received this time is RL with Seq.No = 1,2.
It is confirmed that the status notification message has been transmitted before the C-PDU 300 is retransmitted.

Next, "LENGTH" 422, "SN" 424 and "L" 425 set in the received STATUS-PDU 310-1 and "LENGTH" 404, "SN" set in the retransmission control table 15. 405 and "L" 4
Compare with 06. Here, both LENGTH =
1, SN = 1, L = 1, which is the same.

From this, the RLC-PDU 300 of Seq.No = 1, 2 related to the retransmission request received this time has already been retransmitted and is waiting for its delivery confirmation, and a new retransmission request is included. You can recognize that not. Therefore, the transmitting station performs Seq.
It is decided not to retransmit the RLC-PDU 300 of No = 1 or 2.

Note that the transmitting station transmits Po in the RLC-PDU 300 of Seq.No = 19 transmitted during the period of the transmission interval TTI-5.
When the 11-bit P2 (“P” 303) is set, the receiving station performs the Poll bit P2 (“P” 3) in the protocol process 112-1 executed in the next transmission interval TTI-6.
03), and recognizes the transmission request for STATUS-PDU 310-1. The receiving station returns STATUS-PDU 310-1 at the next transmission interval TTI-7 (not shown).
The reception result of the RLC-PDU 300 of q.No = 1 or 2 will be notified.

As described above, according to the first embodiment, the transmitting station uses the retransmission control table 15 and uses the RLC-PDU 30.
Every time 0 is retransmitted, the transmission reason “Cause” 402 read from the status notification message and the upper limit value “VT (M)” of the sequence number transmitted up to the table setting time
403, the value of the “Poll Counter” 401 at the time of setting, and the sequence number “S” of the retransmitted RLC-PDU 300.
"N" 405 and subsequent numbers "L" 406, "LENGTH" 40
4 is stored in association with each other, so that it is based on Poll bit reception that is received by RLC-PDU300 retransmission and passing.
Unnecessary retransmissions caused by the retransmission request by STATUS-PDU 310-1 can be suppressed, and only necessary retransmissions can be performed, so that it is possible to prevent wasteful consumption of wireless or wired line resources. .

Embodiment 2. FIG. 9 is a sequence diagram illustrating a data packet retransmission control method according to the second embodiment of the present invention. In the second embodiment, an operation example 2 of the data packet retransmission control operation performed in the data packet transmission system shown in FIG. 1 is shown. In FIG. 9, 2 Rs out of 4 RLC-PDUs (Seq.No = 0,1,2,3) 300 transmitted by the transmitting station in the period of transmission interval TTI-0
When the LC-PDU (Seq.No = 1, 2) 300 is missing, the receiving station performs the RLC-PDU receiving process in the protocol process 110-2 performed in the period of the next transmission interval TTI-1, Seq.No =
When missing of 1 and 2 is detected, the following STATUS-PDU (20
0-2) 310-2 is created.

That is, this STATUS-PDU (200-2)
In 310-2, “Miss” indicating “missing detection of transmission sequence number 302” is set in the transmission reason “Cause” 315 in FIG. 7, FIG. 25, and FIG. 26, and “LSN” 41
2 is set to the next value “4” of the sequence number upper limit value “3” in the case of normal reception, and “SN” 424
The leading sequence number “1” of the RLC-PDU 300 requesting retransmission is set to “1”, and the subsequent number “1” is set to “L” 425.

The receiving station receives the STATUS-PDU (200-200-200) having the above contents during the next transmission interval TTI-2.
2) 310-2 is transmitted to the transmitting station to request retransmission. From the retransmission request information element 420 of the received STATUS-PDU (200-2) 310-2 in the STATUS-PDU receiving process in the protocol process 100-2 executed in the period of the next transmission interval TTI-3, the transmitting station Recognizing the missing Seq.No = 1,2,
That is, the retransmission request for the RLC-PDU 300 with Seq.No = 1, 2 is recognized. Then, in this example, the retransmission control table 1
5 does not exist, the retransmission control table 15 is set as follows.

That is, in FIG. 4, "Cause" 40
2 indicates the reason for sending the received STATUS-PDU 310-2 "Ca
“Miss” read from “use” 315 is set.
In “VT (M)” 403, RLC-PDU3 transmitted to the receiving station by the period of the transmission interval TTI-3 determined to be retransmitted
The upper limit value “15” of the sequence number of 00 is set.
In the "SN" 405, the first sequence number "1" fetched from the STATUS-PDU 310-2 is set. "L"
In 406, the subsequent number “1” fetched from STATUS-PDU 310-2 is set. The number of sets “1” is set in “LENGTH” 404. In addition, unlike the first embodiment,
In the RLC-PDU 300 with Seq.No = 11, since the Poll bit is not set, the “Poll Counter” 30 at the time when it is determined to perform retransmission (that is, the transmission interval TTI-3 period) 30
The count value of 6 is "0", and "PollCounter" 40
The value “0” is set in 1.

The transmitting station retransmits the RLC-PDU 300 with Seq.No = 1, 2 during the next transmission interval TTI-4. During the transmission interval TTI-4, Seq.No = 1,
2 RLC-PDU300 of 2 and Seq. Which is the original transmission data.
Two RLC-PDUs 300 of No = 16,17 will be transmitted.

On the other hand, at the receiving station, the period timer 23 has timed out (TO) during the period of the transmission interval TTI-3. Therefore, in the protocol processing 111-2 executed during the period of the transmission interval TTI-3, the time out (TO) has occurred. Recognizes a request to send a status notification message (STATUS-PDU 310-2) based on However, at this time point, the receiving station has not yet received the RLC-PDU 300 of Seq.No = 1, 2 that requested the retransmission. Therefore, the receiving station receives the status notification message (STATUS-PDU (201-2) 310-2) having the following contents.
To create.

That is, this STATUS-PDU (201-2)
In FIG. 7, FIG. 25, and FIG. 26, the reason for transmission 310-3 is “Cause” 315 is “period timer timeout”.
Is set to “TO” and “LSN” 412 is set to STATUS
-The value "12" next to the sequence number upper limit value "11" in the case where the transmission request of the PDU 310-2 is recognized to be received by the period of the transmission interval TTI-3 is set, and "SN" 4
The leading sequence number “1” of the RLC-PDU 300 requesting retransmission is set in 24, and the subsequent number “1” is set in “L” 425.

The receiving station receives the STATUS-PDU (201-201) having the above contents during the next transmission interval TTI-4.
2) 310-2 is transmitted and RLC-PDU300 with Seq.No = 1,2
The re-sending request is sent again to the transmitting station. The transmitting station receives the received STATUS-PDU (201-2) 310-2.
On the other hand, in the STATUS-PDU receiving process in the protocol process 101-2 executed in the period of the next transmission interval TTI-5,
When the retransmission request for the RLC-PDU 300 of Seq.No = 1 or 2 is recognized, the existence of the retransmission control table 15 is confirmed, the retransmission control table 15 is referred to, and the necessity of retransmission execution is determined as follows. .

First, STATUS-PDU (201-2) 310-
The value of “−1” from “LSN” included in 2 and the value of “VT (M)” 403 set in the retransmission control table 15 are compared. LSN-1 = 11 and "VT
It is smaller than the value (15) of (M) 403. As a result, the STATUS-PDU 310-2 received this time has Seq.No = 1,2
It is confirmed that the RLC-PDU 300 is a status notification message transmitted before the retransmission is performed.

Then, the received STATUS-PDU (201-
2) "LENGTH" 422 set in 310-2,
“SN” 424 and “L” 425, and “LENGTH” 404 and “SN” 4 set in the retransmission control table 15
05 and "L" 406. Here, both are LENGTH = 1, SN = 1, L = 1, and are the same.

From this, the RLC-PDU 300 of Seq.No = 1, 2 related to the retransmission request received this time has already been retransmitted and is waiting for its delivery confirmation, and a new retransmission request is included. You can recognize that not. Therefore, the transmitting station performs Seq.
It is decided not to retransmit the RLC-PDU 300 of No = 1 or 2.

The transmitting station sends Po in the RLC-PDU 300 of Seq.No = 19 transmitted during the period of the transmission interval TTI-5.
When the 11 bit P1 (“P” 303) is set, the receiving station polls in the RLC-PDU reception process in the protocol process 112-2 executed in the next transmission interval TTI-6.
Detects bit P1 (“P” 303) and returns STATUS-PDU31
Recognize the 0-1 transmission request. The receiving station returns STATUS-PDU 310-1 at the next transmission interval TTI-7 (not shown). The receiving station uses the STATUS-PDU 310-1 to be returned, and the RLC-PDU 300 of Seq.No = 1 or 2 retransmitted by the transmitting station.
Will be notified of the reception result about.

As described above, according to the second embodiment, the transmitting station uses the retransmission control table 15 and uses the RLC-PDU 30.
Every time 0 is retransmitted, the transmission reason “Cause” 402 read from the status notification message and the upper limit value “VT (M)” of the sequence number transmitted up to the table setting time
403, the sequence number “SN” 405 of the retransmitted RLC-PDU 300, and the subsequent numbers “L” 406, “LENGTH”
RLC-PDU 30 because it is stored in association with 404.
It is possible to suppress unnecessary retransmission due to a retransmission request by STATUS-PDU 310-2 based on the timeout of the periodic timer received with 0 retransmission and passing, and it is possible to carry out only necessary retransmission, so that the wireless line Alternatively, it is possible to prevent the resources of the wired line from being wasted.

Third Embodiment FIG. 10 is a sequence diagram illustrating a data packet retransmission control method according to the third embodiment of the present invention. The third embodiment shows an operation example 3 of the data packet retransmission control operation performed in the data packet transmission system shown in FIG.
In FIG. 10, 2 out of 4 RLC-PDUs (Seq.No = 0,1,2,3) 300 transmitted by the transmitting station during the transmission interval TTI-0
When there are missing RLC-PDUs (SN = 1, 2) 300, the receiving station, in the RLC-PDU receiving process in the protocol process 110-3 performed in the period of the next transmission interval TTI-1, Seq.N
When o = 1,2 omission is detected, the receiving station
S-PDU (200-3) 310-2 is created.

That is, this STATUS-PDU (200-3)
In FIG. 7, FIG. 25, and FIG. 26, the transmission reason “Cause” 315 is set to 310-2, “Miss” indicating “missing detection of transmission sequence number 302” is set, and “LSN” 41.
2 is set to the next value “4” of the sequence number upper limit value “3” in the case of normal reception, and “SN” 424
The leading sequence number “1” of the RLC-PDU 300 requesting retransmission is set to “1”, and the subsequent number “1” is set to “L” 425. The receiving station, during the next transmission interval TTI-2, has the STATUS-PDU (200-
3) 310-2 is transmitted and a retransmission request is made to the transmitting station.

The transmitting station receives the STATUS-PDU (200-3) 310 in the STATUS-PDU receiving process in the protocol process 100-3 executed during the next transmission interval TTI-3.
-2 is recognized from the retransmission request information element 420 of -2, that is, the retransmission request for the RLC-PDU 300 of Seq.No = 1, 2 is recognized. In this example, since the retransmission control table 15 does not exist, the retransmission control table 15 is set as follows.

That is, in FIG. 4, "Cause" 40
2 indicates the reason for sending the received STATUS-PDU 310-2 "Ca
The transmission reason “Miss” read from “use” 315 is set. The “VT (M)” 403 contains the RLC transmitted to the receiving station by the period of the transmission interval TTI-3 determined to be retransmitted.
-The upper limit value "15" of the sequence number of the PDU 300 is set. In the "SN" 405, the first sequence number "1" fetched from the STATUS-PDU 310-2 is set.
In “L” 406, the subsequent number “1” fetched from STATUS-PDU 310-2 is set. The number of sets “1” is set in “LENGTH” 404. In addition, as in the first embodiment,
In RLC-PDU300 with Seq.No = 11, Poll bit P1
("P" 303) is set, so "P" at the time when it is determined to perform retransmission (that is, the period of the transmission interval TTI-3)
The count value of “oll Counter” 306 is “1”, and
The value “1” is set in the “oll Counter” 401.

The transmitting station retransmits the RLC-PDU 300 with Seq.No = 1, 2 during the next transmission interval TTI-4. During the transmission interval TTI-4, Seq.No = 1,
2 RLC-PDU300 of 2 and Seq. Which is the original transmission data.
Two RLC-PDUs 300 of No = 16,17 will be transmitted.

On the other hand, at the transmitting station, Poll is performed in the RLC-PDU 300 of Seq.No = 11 which is transmitted during the period of the transmission interval TTI-2.
When bit P1 (“P” 303) is set, Poll
Counter 13 is incremented, and the count value "1" is used as the request number and "Poll Counte" of RLC-PDU300.
r "306. That is, during the transmission interval TTI-2, the status notification request and the request number bound to the receiving station are sent.
The RLC-PDU 300 is transmitted. At this time, the transmitting station transmits RLC-PDU3 with Seq.No = 9 during the transmission interval TTI-2.
Suppose 00 did not reach the receiving station correctly.

As a result, the receiving station receives the next transmission interval TTI-3.
RLC-PD in protocol processing 111-3 executed during the period
In the U reception process, the omission of the RLC-PDU 300 of Seq.No = 9 is detected, and it is detected that the Poll bit P1 (“P” 303) is set in the RLC-PDU 300 of Seq.No = 11. However, at this point in time, the receiving station has not yet received the RLC-PDU 300 of Seq.No = 1, 2 that requested retransmission. Therefore, the receiving station receives the status notification message (STATUS-PDU (201-3) 310-
1, 310-2) is created.

That is, in the STATUS-PDU (201-3) 310-1 created in the RLC-PDU receiving process in the protocol process 111-3 executed in the period of the transmission interval TTI-3, in FIG. As shown in FIG.
“P1” indicating “reception of Poll bit P1 (“ P ”303)” is set in “e” 315, and the request number (“Poll C
"until" 316) is set to the value "1" read from "Poll Counter" 306 of the received status notification request message, and until "LSN" 412 is the transmission interval TTI-3 period at which the status notification message transmission request is recognized. The next value "12" of the sequence number upper limit value "11" in the case where the sequence number can be received is set. Further, the “SN” 424 and the “L” 425 include the retransmission request “SN = 1, L = 1” for the RLC-PDU 300 with Seq.No = 1, 2 and the RL with Seq.No = 9.
Retransmission request for C-PDU300 "SN = 9, L = 0"
Are set, and “2” is set in the “LENGTH” 422.

The receiving station, during the next transmission interval TTI-4, has a STATUS-PDU (201-
3) 310-1 is transmitted, and RLC-PDU30 of Seq.No = 1, 2, 9
The retransmission request for 0 is notified to the transmitting station. For the STATUS-PDU (201-3) 310-1 received by the transmitting station, in the STATUS-PDU receiving process in the protocol process 101-3 executed in the period of the next transmission interval TTI-5, the transmitting station Se
When the retransmission request for the RLC-PDU 300 with q.No = 1, 2, 9 is recognized, the existence of the retransmission control table 15 is confirmed, the retransmission control table 15 is referred to, and the necessity of retransmission execution is determined as follows. to decide.

First, STATUS-PDU (201-3) 310-
The value obtained by subtracting “−1” from “LSN” included in 1 and the “VT (M)” 403 set in the retransmission control table 15 are compared in size. LSN-1 = 11 and "VT
It is smaller than the value (15) of (M) 403. As a result, the STATUS-PDU 310-1 received this time has Seq.No = 1,2
It is confirmed that the RLC-PDU 300 is a message transmitted before the retransmission is performed.

Next, STATUS-PDU (201-3) 310
"LENGTH" 422 and "SN" 42 set to -1
4 and “L” 425 are compared with “LENGTH” 404, “SN” 405 and “L” 406 set in the retransmission control table 15. Here, the “LENGTH” 404 of the retransmission control table 15 is “1”, but STATUS-P
The “LENGTH” 422 of the DU 310-1 is “2”. The retransmission control table 15 has the settings of “SN = 1, L = 1”, but does not have the settings of “SN = 9, L = 0”.

From this, consecutive sequence numbers Seq.No. of Seq.No = 1, 2, 9 related to the retransmission request received this time.
For RLC-PDU300 with No = 1 or 2, it has already been retransmitted and is waiting for its delivery confirmation.
Regarding q.No = 9, it can be recognized that the request is a new retransmission request.

Therefore, the transmitting station performs the STATUS-P in the protocol processing 101-3 executed during the transmission interval TTI-5.
In the DU reception process, it is determined that the RLC-PDU 300 with Seq.No = 1 and 2 is not retransmitted, but only the RLC-PDU 300 with Seq.No = 9 is retransmitted. That is, the retransmission control table 15 shown in FIG. 4 is newly set for Seq.No = 9. as a result,
During the next transmission interval TTI-6, Seq.No = 9 related to retransmission
RLC-PDU300 and original transmission data SN = 22,23,24
The three RLC-PDUs 300 will be transmitted. Since the retransmission control table 15 is deleted due to a notification of successful retransmission, etc., the retransmission control table for Seq.No = 1,2 and the retransmission control table for Seq.No = 9 coexist until then. It will be.

Note that the transmitting station sends Po in RLC-PDU300 of Seq.No = 19 which is transmitted during the transmission interval TTI-5.
When the 11 bit P2 (“P” 303) is set, the receiving station performs the Poll bit P2 (“P” 303) in the RLC-PDU reception process in the protocol process 112-3 executed during the transmission interval TTI-6. Is detected, and STATUS-PDU310-
Recognize the transmission request of 1. The receiving station returns STATUS-PDU 310-1 at the next transmission interval TTI-7 (not shown). The receiving station notifies the reception result of the RLC-PDU 300 of Seq.No = 1, 2 retransmitted by the transmitting station by the STATUS-PDU 310-1 returned.

As described above, according to the third embodiment, the transmitting station uses the retransmission control table 15 and uses the RLC-PDU 30.
Every time 0 is retransmitted, the transmission reason “Cause” 402 read from the status notification message and the upper limit value “VT (M)” of the sequence number transmitted up to the table setting time
403, the value of the “Poll Counter” 401 at the time of setting, and the sequence number “S” of the retransmitted RLC-PDU 300.
"N" 405 and subsequent numbers "L" 406, "LENGTH" 40
4 is stored in association with each other, so that it is based on Poll bit reception that is received by RLC-PDU300 retransmission and passing.
Unnecessary retransmissions caused by the retransmission request by STATUS-PDU 310-1 can be suppressed, and only necessary retransmissions can be performed, so that it is possible to prevent wasteful consumption of wireless or wired line resources. .

Fourth Embodiment 11 to 13 are flowcharts for explaining the data packet retransmission control method according to the fourth embodiment of the present invention. The fourth embodiment shows a general data packet retransmission control operation performed by the transmitting station, including the data packet retransmission control operation (operation examples 1 to 3) described in the first to third embodiments. Below, FIG.
4 to FIG. 6, FIG. 10 to FIG. 25, and FIG.

11 to 13, in the transmitting station, the packet (PDU) sent from the receiving station is checked (step ST1), and whether or not the status notification message is received by the "PDU-type" 311. Is determined (step ST2). When the status notification message is not received, the determination result is negative (step ST2: No), the process proceeds to step ST17, and the data packet transmission process (steps ST17 to ST21) is executed. If the status notification message is received, the determination result is affirmative (step ST2: Yes), the process proceeds to step ST3, and the retransmission control process (steps ST3 to ST2) is performed.
7) is executed.

First, the data packet transmission process (steps ST17 to ST21) will be described. Step S
At T17, it is determined whether or not a new PDU is sent from the upper layer. When a new PDU is sent,
The determination result is affirmative (step ST17: Yes),
The process proceeds to step ST18, and the data packet (PDU) received so far and the retransmission data generation process (step ST1
3 to ST16), the retransmitted data packet (PD
Transmission data packet (PD) including new PDU in (U)
U) is created. Next, it is determined whether or not the Poll bit needs to be set (step ST19), and if the determination result is affirmative (step ST19: Yes), step ST2
Go to 0 and Pol to the corresponding data packet (PDU)
The l bit is set, and at the same time, the Poll Counter 13 is incremented. After that, the data packet (RLC-PDU3
00) transmission processing is executed (step ST21).
When it is determined in step ST19 that the Poll bit is not set (step ST19: N
o), the process directly proceeds to step ST21, and the data packet (RLC-PDU300) transmission process is executed as it is.

On the other hand, in step ST17, the new P
When the DU is not sent, the determination result is negative (step ST17: No), and it is determined whether the Poll bit needs to be set (step ST22). When the determination result is affirmative (step ST22: Yes), step S
The process proceeds to T23, and the last transmitted data packet (PD
U) has the Poll bit set and at the same time Poll Counter
13 is incremented. After that, the transmission process of the data packet (RLC-PDU300) is executed (step ST21). In this case, the data packet (RLC-PDU300) having the same sequence number will be repeatedly transmitted. In step ST22, Po
When it is determined that the 11 bit is not set (step ST22: No), the transmission process is not performed, and the process is ended.

Next, a retransmission control process (steps ST3 to S
T27) will be described. In step ST3, it is investigated whether or not the received status notification message includes the resend request information element 420. If included, “LENGTH” 422, “SN” 424, of the retransmission request information element 420.
“L” 425 is taken out and held. Thereafter, it is determined whether or not the retransmission control table 15 exists (step S
T4). Here, for example, the determination is made based on the 1-bit retransmission control table presence / absence flag. If at least one retransmission control table 15 exists, the retransmission control table presence / absence flag is set.

If the retransmission control table 15 does not exist, the determination result in step ST4 is negative (step ST4).
4: No), the process proceeds to step ST13, and the retransmission data packet generation process (step ST1) is performed as follows.
3 to ST16) are executed and retransmission is performed (steps ST18 to ST21). These are the processing operations during the above-described transmission intervals TTI-3 and TTI-4, for example.

In step ST13, it is determined whether or not the resend request information element 420 is stored. If it is stored, the determination result is affirmative (step ST13:
Yes), the process proceeds to step ST14 and step S
"LENGTH" of the resend request information element 420 saved in T3
A corresponding data packet is read from the storage device based on the information of 422, “SN” 424, and “L” 425, and preparation for transmission of a data packet (retransmission PDU) to be retransmitted is performed. In parallel, the retransmission control table 15 is created as described in FIG. 4 (step ST15). When the creation is completed, the retransmission control table presence / absence flag is set (step ST16), and the retransmission is performed as described above (steps ST18 to ST21).

If the retransmission request information element 420 is not stored in step ST13, the determination result is negative (step ST13: No), and step S13
Proceeding to T17, normal data is transmitted as described above (steps ST17 to ST23). This route includes the case where the retransmission is successful.

On the other hand, in step ST4, when the retransmission control table 15 exists, the result of the determination in step ST4 is affirmative (step ST4: Yes), the process proceeds to step ST5, and the information of the received status notification message is sent. Whether or not retransmission is necessary based on the control table 1
The deletion / addition processing of No. 5 is executed (step ST5).
ST27). These are, for example, the transmission interval TTI-5 described above.
And a subsequent transmission interval (a transmission interval TTI-8, TTI-11, etc. (not shown)) at a corresponding transmission interval.

First, in step ST5, the following information (1) to (3) is read from the received status notification message. (1) The request number (Poll Counter 316) is read. Hereinafter referred to as "PCs". This is read when the status notification message is STATUS-PDU 310-1. (2) The transmission reason “Cause” 315 is read. Hereinafter referred to as "CAs". This is read regardless of whether the status notification message is STATUS-PDU 310-1 or 310-2. (3) Upper limit "LSN-1"
Is read. Hereinafter referred to as "VTMs". This is because the status notification message is STATUS-PDU 310-1, 310-
In any case of 2, it is read.

Next, the pointer of the retransmission control table 15 is set to the head (step ST6), and the retransmission control table 1
The following information (1) to (4) is read from 5.
(1) The request number (Poll Counter 401) is read. Hereinafter referred to as "PCt". Since "PCt" may not be set in the table in some cases, it may not be read out. (2) The transmission reason “Cause” 402 is read.
Hereinafter referred to as "CAt". This is always read.
(3) The upper limit value “VT (M)” is read. Below "V
TMt ". This is always read. (4)
“SN” 405, “L” 406, and “LENGTH” 404 are read. These are the retransmitted information.

At the next step ST8, it is determined whether or not the upper limit value VTMs read from the status notification message is larger than the upper limit value VTMt read from the retransmission control table 15. That is, it is determined whether or not the status notification message received this time is created after the table is set (after the retransmission is decided).

In the judgment at step ST8, VTM
If s> VTMt, the determination result is affirmative (step ST8: Yes), the process proceeds to step ST9, and the retransmission control table 15 is deleted. This is the transmission interval
This is the processing performed during the TTI-8 period and the corresponding transmission interval period thereafter. During these periods, the success or failure of retransmission is recognized. Therefore, if the retransmission is successful, the control table 15 is deleted again because it is no longer necessary. If the retransmission fails, the setting of the control table 15 is performed again and the corresponding control table 15 is deleted again. To do.

Next, in step ST10, it is determined whether or not the next retransmission control table 15 exists. If the determination result is affirmative (step ST10: Yes), the pointer of the retransmission control table 15 is set to the head (step ST11), the process returns to step ST7, and the upper limit value is compared. On the other hand, the next retransmission control table 15
Is not present, the determination result is negative (step ST1
0: No), the process proceeds to step ST12, the retransmission control table presence / absence flag is reset, and the process proceeds to step ST13.

For example, in the retransmission confirmation process during the transmission interval TTI-8, when the retransmission failure is recognized, the content of the retransmission request information element 420 is stored in step ST3. In step ST13 after deletion, the determination result is affirmative (step ST1
3: Yes), the retransmission control table 15 is newly created (steps ST14 to ST16), and the retransmission is performed again (steps ST18 to ST21). If the retransmission is successful, the content of the retransmission request information element 420 is not saved in step ST3, and therefore the determination result is negative (step ST13: No) in step ST13 after the table is deleted, and the normal Data transmission is performed (steps ST17 to ST21).

Now, in the judgment at step ST8,
When VTMs> VTMt is not satisfied, the determination result is negative (step ST8: No), the process proceeds to step ST24, and the retransmission necessity determination process (step S) is performed as follows.
T24 to ST27) are performed. First, step ST2
At 4, it is determined whether VTMs = VTMt. When VTMs = VTMt is not satisfied, that is, VTMs <
If it is VTMt, the determination result is negative (step S
(T24: No), the process proceeds to step ST27, and the confirmation process of retransmitted is performed. That is, the difference between the information in the retransmission control table 15 and the retransmission request of the received status notification message is extracted, and if there is a difference, “LENGTH” 422, “SN” 424, “L” 4 of the retransmission request information element 420 is extracted.
25 is retained. Then, it progresses to step ST13 via step ST10 and step ST12.

For example, the transmission interval TT in FIG. 8 and FIG.
In the retransmission completion confirmation process in the period of I-5, the difference cannot be extracted, so the determination in step ST13 is negative (step S
(T13: No), the process proceeds to step ST17 and Seq.
Unnecessary retransmissions for No = 1 and 2 are not performed, and only normal data transmission is performed (steps ST17 to ST23).
However, in the retransmission completion confirmation processing in the period of the transmission interval TTI-5 in FIG. 9, since the difference can be extracted, step ST
The determination result of 13 is affirmative (step ST13: Yes), the process proceeds to step ST14, and a retransmission control table 15 for Seq.No = 9 is newly created (step ST1
4 to ST16), unnecessary retransmission for Seq.No = 1,2 is not performed, and retransmission for Seq.No = 9 is performed along with normal data transmission (steps ST18 to ST21).

On the other hand, steps ST17 → ST22 → ST
Since the data packet having the same sequence number may be transmitted as described in the processing of No. 23, the VTM
In some cases, s = VTMt. This is the transmission interval TTI-
It is considered that it will occur not only in the period of 5 but also in the period of the transmission interval TTI-8 thereafter and the period thereafter. VT
When Ms = VTMt, the determination result in step ST24 is affirmative (step ST24: Yes), and the transmission reason CAs of the received status notification message is “Po
"Il bit received" or "Time Out of the periodic timer
(Time-out) "is determined (step S
T25, ST28).

CAs = Poll (the transmission reason CAs is "P
If it is the reception of all bits "), step ST2
The determination result of 5 is affirmative (step ST25: Yes), the process proceeds to step ST26, and it is determined whether or not PCs> PCt, that is, the relationship between the request numbers. PCs
When> PCt, the determination result of step ST26 is affirmative (step ST26: Yes), the process proceeds to step ST9, and the corresponding retransmission control table 15 is deleted. This is because, for example, in the retransmission completion confirmation process in the transmission period TTI-8, when the retransmission success can be confirmed or the retransmission failure can be confirmed, CAs = Miss set in the transmission period TTI-5 is set. This corresponds to the case where the retransmission control table 15 is deleted by. When the retransmission failure can be confirmed, the process proceeds to steps ST10 → ST12 → ST13, a new retransmission control table 15 is created, and the retransmission is performed again (steps ST13 to ST21). Also, PC
When s ≦ PCt, the determination result of step ST26 is negative (step ST26: No), the process proceeds to step ST27, and the difference is extracted as described above. After that, the process proceeds from step ST10 to ST12 to ST13, and unnecessary retransmission is not performed, but necessary retransmission is performed (steps ST13 to ST21).

If CAs = Time Out (the transmission reason CAs is "Time out of the periodic timer (timeout)"), the determination in step ST28 is affirmative (step ST2).
8: Yes), the process proceeds to step ST29 and CAs
= CAt is determined. For example, in FIG. 9, in the retransmission completion confirmation processing in the transmission period TTI-5, CA
s = TO (Time Out of period timer) and CAt = Mi
Although it is ss, CAs = CAt = Time Out may occur in the retransmission confirmation processing in the corresponding period after the transmission period TTI-8. In this case, the determination result of step ST29 is affirmative (step ST29: Yes), the process proceeds to step ST9, and the corresponding retransmission control table 15 is deleted. This is because the transmission period TTI-
This corresponds to the case where the retransmission control table 15 based on CAs = Miss set in the period of 5 is deleted. If the resend failure can be confirmed, steps ST10 → ST12 → ST13.
Then, a new retransmission control table 15 is created and the retransmission is performed again (steps ST13 to ST21).

When CAs = CAt is not satisfied, that is, when CAt = Poll is satisfied, step ST is executed.
The determination result of 29 is negative (step ST29: No), the process proceeds to step ST27, and the difference is extracted as described above. Then, step ST10 → ST12 →
Proceeding to ST13, unnecessary retransmission is not carried out, but necessary retransmission is carried out (steps ST13 to ST21). If the transmission reason CAs is not the reception of the Poll bit (step ST25: No) and is not Time Out (timeout) (step ST28: No), that is, if the missing detection “Miss” is detected, the process directly proceeds to step ST27.
The difference is extracted as described above. After that, the process proceeds from step ST10 to ST12 to ST13, and unnecessary retransmission is not performed and necessary retransmission is performed (step ST13).
~ ST21).

As described above, according to the fourth embodiment,
Create a retransmission control table that sets the upper limit value of the sequence number of the data packets that can be transmitted until the retransmission execution decision, and set the upper limit value of the sequence number included in the received status notification message and the upper limit of the sequence number of the retransmission control table. The size of the value information is compared to determine when the received status notification message was created. In addition, the receiver side added the reason for sending to the status notification message in preparation for the case where a data packet with the same sequence number is sent, so it is possible to judge whether retransmission is necessary or not based on them. You will be able to do it properly.

Embodiment 5. FIG. 14 is a block diagram showing the configuration of a multicast data packet transmission system according to a fifth embodiment of the present invention. 15 is the same as FIG.
5 is a diagram showing a configuration example of a retransmission control table provided for retransmission control by the transmitting station shown in FIG.

As shown in FIG. 14, the multicast data packet transmission system includes a transmitting station 1a which is a multicast data packet transmitting device and a plurality of receiving stations (reception station 2a in FIG. 14) which are multicast packet data receiving devices. , 2b, 2c are shown) to transmit and receive via an individual transmission path (individual wireless transmission path or individual wired transmission path) or a common transmission path (common wireless transmission path or common wired transmission path). It is configured.

That is, the transmitting station 1a includes the individual transmission lines (individual wireless transmission lines or individual wired transmission lines) or common transmission lines (common wireless transmission lines or common wired transmission lines) 3a, 3
Multicast data packet (RLC
-PDU) is transmitted to a plurality of receiving stations 2a, 2b, 2c. The transmission path from the transmitting station to the receiving station is called a downlink transmission path, and the multicast data packet (RLC-PDU) is transmitted using the multicast channel on the downlink transmission path.

The plurality of receiving stations 2a, 2b, 2c are
Stations that send status notification messages (STATUS-PDU) using individual transmission lines (individual wireless transmission lines or individual wired transmission lines) or common transmission lines (common wireless transmission lines or common wired transmission lines) 4a, 4b, 4c, respectively To send to. The transmission path from this receiving station to the transmitting station is called the uplink transmission path, and the status notification message (STATUS-PDU) is sent using the uplink dedicated channel on the uplink dedicated transmission path or the uplink common channel on the uplink common transmission path. To be done.

The transmitting station 1a shown in FIG.
However, in the fifth embodiment, P
Retransmission control is performed without using the ol bit or the Poll Counter 13. Therefore, the retransmission control table is not the retransmission control table 15 shown in FIG. 4, but the retransmission control table 150 having the configuration shown in FIG. 15 is used. The format shown in FIG. 23 is used as the format of the multicast data packet (RLC-PDU).

The receiving stations 2a, 2b, 2c are each constructed as shown in FIG. 5, for example. In FIG. 5, the transmission reason creation unit 24 creates a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting non-unconditional retransmission in response to a dropout detection or a timeout. It should be noted that there is no case where a reason for transmission is created in response to a message request. In the status notification message creating section 25,
The status notification message (STATUS-PDU) is shown in FIG. 7, FIG. 25, and FIG.
It is created in the format shown in 6.

The retransmission control table 150 shown in FIG.
The SN 151, the VTMt 152, and the retransmission flag 153 are composed of three item columns. A series of sequence numbers of the multicast data packet (RLC-PDU) to be transmitted is set in the SN 151. In FIG. 15, SN15
In 1, a series of sequence numbers from number 0 to number 2047 is set.

When performing retransmission, the VTMt 152 transmits within the transmission interval TTI in which the retransmission is performed in the line in which the sequence number of the multicast data packet (RLC-PDU) for which the retransmission is performed in SN 151 is described. The upper limit value of the sequence number of the multicast data packet (RLC-PDU) to be set is set.

Retransmission flag 153 is set to "OFF" for each sequence number in SN 151 when retransmission has not been performed.
The flag is set, and the "ON" flag is set when the retransmission is performed. That is, the retransmission flag 153 contains VTMt15.
When a valid value is set to 2, the "ON" flag indicating that retransmission has been performed is set for the corresponding sequence number. Then, when the same-numbered new multicast data packet (RLC-PDU) is transmitted, the flag is cleared and the “OFF” flag indicating that retransmission has not been performed is set.

Next, with reference to FIG. 16, a description will be given of the retransmission control operation of the multicast data packet implemented in the multicast data packet transmission system shown in FIG. 14 (operation example 1). Note that FIG. 16 is a sequence diagram illustrating the retransmission control operation of the multicast data packet when the uplink common channel is used for transmitting the status notification message from the receiving station to the transmitting station.

Similar to the first to fourth embodiments described above,
This Embodiment 5 and Embodiments 6 to be described later
9 also shows an example in which four multicast data packets (RLC-PDU) are transmitted at each transmission interval TTI. Further, the transmitting station 1a and the receiving stations 2a, 2b, 2c have the same transmission interval TTI, and it is also the same that the transmission and reception timings are not deviated. However, the multicast data packet (RLC-PDU) used in the fifth embodiment and the sixth to ninth embodiments described below is configured in the format shown in FIG. 23 as described above. After that, multicast data packet (RLC-PDU)
Is simply referred to as "RLC-PDU" or "RLC-PDU300a". Also, a status notification message (STATUS-PDU) 310-2
Is simply "STATUS-PDU" or "STATUS-PDU310-
2 ”.

In FIG. 16, the transmitting station 1a determines the transmission interval.
4 RLC-PDUs (Seq.No = 0,1,2,3) during TTI-0 period
300a is transmitted. The receiving station 2a receives the next transmission interval TTI-
R in protocol processing 110-4a executed during period 1
In the LC-PDU receiving process, the transmitting station 1a sends the transmission interval TTI-0.
Of 4 RLC-PDUs (Seq.No = 0,1,2,
3) One RLC-PDU (Seq.No = 1) 300 out of 300a
Since the omission of a has been detected (SN = 1 omission detected), the STATUS-PDU (200-4a) 310-2 requesting retransmission is created as follows.

The receiving station 2b also performs the RLC-PD in the protocol processing 110-4b executed during the same transmission interval TTI-1.
In the U reception processing, the four RLC-PDUs (Seq.No = 0,1,2,3) 3 transmitted by the transmitting station 1a during the transmission interval TTI-0 3
Two RLC-PDUs (Seq.No = 1,2) 300a out of 00a
Is detected (SN = 1, 2 omission is detected), the STATUS-PDU (200-4b) 310-2 requesting retransmission is created as follows.

That is, STATUS-PDU (200-4a) 3
10-2 and STATUS-PDU (200-4b) 310-2, in FIG. 7, FIG. 25, and FIG.
e ”315 is set to“ detection of missing transmission sequence number 302 ”
“Miss” indicating is set. The "LSN" 412 is set to the next value (sequence number expected to be received next) "4" next to the upper limit value (described as "VTMs") "3" of normally received sequence number. The sequence number “1” at the beginning of the RLC-PDU 300a requesting retransmission is set in the “SN” 424. “L” 425 includes the information of the receiving station 2a.
In the STATUS-PDU (200-4a) 310-2, the subsequent number "0" is set, and the STATUS-PDU (200-
4b) In 310-2, the subsequent number "1" is set.

The receiving stations 2a and 2b both request the transmitting station to retransmit, so that the STATUS-PDU (200-200) having the above-mentioned contents is provided during the next transmission interval TTI-2.
4a) 310-2, STATUS-PDU (200-4b) 310
-2 on the uplink common channel. That is, the acquisition control of the access right to the uplink common channel is executed. As a result, the receiving station 2a acquires the transmission right, and the transmission interval
STATUS-PDU (200-4a) 3 during the TTI-2 period
10-2 is transmitted on the uplink common channel. Also, the receiving station 2b acquires the right to transmit on the uplink common channel after a random time interval, for example, during a transmission interval TTI-7 after 5 transmission intervals, and the STATUS-PDU (200-4b) 3
10-2 is transmitted on the uplink common channel.

The transmitting station 1a uses the STATUS-PDU in the protocol processing 100-4 executed during the next transmission interval TTI-3.
In the receiving process, the STATUS-P received from the receiving station 2a
One RLC-PDU (Seq. From DU (200-4a) 310-2.
No = 1) Recognize the retransmission request of 300a. by this,
The transmitting station 1a checks the retransmission control table 150 shown in FIG. 15 and requests the retransmission request RLC-PDU 300 of Seq.No = 1.
Check the retransmission status of a. The retransmission flag 153 for SN = 1 in SN 151 is “OFF”.

Therefore, the transmitting station 1a determines that the retransmission has not been performed, and prepares for the retransmission of the RLC-PDU 300a with Seq.No = 1. In the retransmission control table 150, the value of VTMt152 for SN = 1 in SN151 is set to the transmission interval TTI-3.
Upper limit value of the sequence number transmitted during the period
5 ”, and the corresponding retransmission flag 153 is set to the“ ON ”flag. Then, the transmitting station 1a receives the next transmission interval.
Retransmission RLC-PDU (Seq.No = 1) 300a during TTI-4 period
At the same time, the new RLC-PDU (Seq.No = 16,17,18) 300a is transmitted using the multicast channel on the downlink transmission path.

In the receiving station 2a, the RLC-PD in the protocol processing 111-4a executed in the period of the next transmission interval TTI-5.
In the U reception process, the four RLC-PDUs (Seq.No = 1,16,17,18) transmitted by the transmitting station 1a during the transmission interval TTI-4
RLC-PDU with Seq.No = 1 that was received correctly and requested retransmission
Reception of 300a is confirmed (SN = 1 retransmission confirmation).

The receiving station 2b also performs the RLC-PD in the protocol processing 111-4b, which is executed during the same transmission interval TTI-5.
In the U reception process, the four RLC-PDUs (Seq.No = 1,16,17,18) transmitted by the transmitting station 1a during the transmission interval TTI-4
Was received correctly and tried to request retransmission Seq.No = 1,2
RLC-PDU300a with Seq.No = 1
Is confirmed (SN = 1 retransmission confirmation).

On the other hand, the receiving station 2c has the same transmission interval.
Protocol processing 111-4c executed during the period of TTI-5
In the RLC-PDU reception process in the
4 RLC-PDUs (Seq.No = 1,
16,17,18), one RLC-PDU (Seq.No = 17) 300
Since the omission of a has been detected (SN = 17 omission detected), STATUS-PDU (200-4c) 310-2 requesting retransmission is created.

This STATUS-PDU (200-4c) 310-
2, the transmission reason "Ca
“Miss” indicating “missing detection of transmission sequence number 302” is set in “use” 315. Upper limit value (VTMs) of the sequence number that was successfully received by the "LSN" 412
The value next to “18” (the sequence number expected to be received next) “19” is set. "SN" 424: Start sequence number "17" of RLC-PDU300a requesting retransmission
Is set. The subsequent number “0” is set in “L” 425.

In order to request the transmitting station to retransmit, the receiving station 2c has the STATUS-PDU (200-4c) 310 having the above contents during the next transmission interval TTI-6.
-2 on the uplink common channel. That is, the acquisition control of the access right to the uplink common channel is executed. As a result, the receiving station 2c acquires the transmission right, and STATUS-P
DU (200-4c) 310-2 is transmitted on the uplink common channel.

Here, as described above, the next transmission interval TT
In the period of I-7, the receiving station 2b receives the STATUS-PDU (2
00-4b) 310-2 is transmitted on the uplink common channel. The receiving station 2b has already received the RLC-PDU 300a with Seq.No = 1 during the previous transmission interval TTI-5. However, STATUS- that is transmitted during this transmission interval TTI-7
Since the PDU (200-4b) 310-2 is created by the protocol process 110-4b in which the omission is detected, a retransmission request is made for the RLC-PDU 300a with Seq.No = 1,2.

The transmitting station 1a uses the STATUS-PDU in the protocol processing 101-4 executed in the next transmission interval TTI-7.
In the receiving process, STATUS-P received from the receiving station 2c
One RLC-PDU (Seq. From DU (200-4c) 310-2.
No = 17) Recognize the retransmission request of 300a. by this,
The transmitting station 1a checks the retransmission control table 150 shown in FIG. 15 and requests the retransmission of the RLC-PDU 300 of Seq.No = 17.
Check the retransmission status of a. SN in SN151 = 17
The re-transmission flag 153 for the flag is "OFF".

Therefore, the transmitting station 1a determines that the retransmission has not been performed, and prepares for the retransmission of the RLC-PDU 300a with Seq.No = 17. In the retransmission control table 150, the value of VTMt152 for SN = 17 in SN151 is set to the transmission interval TTI-
The upper limit of the sequence number transmitted during the period of 7 is set to "30", and the corresponding retransmission flag 153 is set to "O".
Set the N "flag.

Then, the transmitting station 1a receives the next transmission interval TTI-
In the period of 8, the new RLC-PDU (Seq.No = 31, 32, 33) 300a together with the retransmitted RLC-PDU (Seq.No = 17) 300a is transmitted using the multicast channel on the downlink transmission path. The receiving station 2c confirms the reception of the retransmitted RLC-PDU (Seq.No = 17) 300a in the RLC-PDU receiving process in the protocol process 111-4c performed during the next transmission interval TTI-8 (SN = 17 resend confirmation).

At this time, the transmitting station 1a further performs the protocol processing 10 executed during the transmission interval TTI-8.
In the STATUS-PDU reception processing in 2-4, a retransmission request for two RLC-PDUs (Seq.No = 1,2) 300a from the STATUS-PDU (200-4b) 310-2 received from the receiving station 2b. Recognize. As a result, the transmitting station 1a checks the retransmission control table 150 shown in FIG.
Check the retransmission status of the RLC-PDU 300a with q.No = 1,2. SN
The retransmission flag 153 for SN = 1 in 151 is
Since it is "ON", it has been retransmitted. On the other hand, SN = 2
Since the re-transmission flag 153 for is "OFF",
It can be seen that the retransmission has not been performed.

Therefore, the transmitting station 1a determines the necessity of retransmission for SN = 1 in SN151 as follows. That is, the STATUS-P received from the receiving station 2b
The upper limit value VTMs of the sequence number set in the DU (200-4b) 310-2 and the upper limit value VTMt of the sequence number set in the retransmission control table are compared in size to determine whether retransmission for SN = 1 is required. Decide no. Here, VTMs = 3 and VTMt = 15, so V
TMs <VTMt, and it is determined that retransmission is unnecessary, and SN =
1, that is, the RLC-PDU 300a with Seq.No = 1 is not prepared for retransmission again.

On the other hand, since SN = 2 in SN151 is retransmitted, RLC-PDU300a of Seq.No = 2 is performed.
Prepare to resend. In the retransmission control table 150, the SN
= 2, the upper limit of the sequence number transmitted in the period of the transmission interval TTI-8 to the value of VTMt152 "3"
3 ”is set, and the retransmission flag 153 is set to the“ ON ”flag.

Then, the transmitting station 1a receives the next transmission interval TTI-
In 9, the new RLC-PDU (Seq.No = 34, 35, 36) 300a is transmitted together with the retransmitted RLC-PDU (Seq.No = 2) 300a using the multicast channel on the downlink transmission path. Receiving station 2
In b, in the RLC-PDU reception process in the protocol process 112-4b executed in the period of the next transmission interval TTI-10, reception of the retransmitted RLC-PDU (Seq.No = 2) 300a is confirmed (SN = 2). Resend confirmation).

As described above, according to the fifth embodiment,
The transmitting station that transmits the multicast data packet is a retransmission request or a state notifying message 200-
4a and the status notification message 200-4b, the retransmission control table corresponding to the multicast data packet is used to suppress the redundant retransmission of the retransmission requests. You can Therefore, it is possible to prevent wasteful consumption of resources on the downlink transmission path (wireless transmission path or wired transmission path).

Sixth Embodiment FIG. 17 is a sequence diagram for explaining a retransmission control method for multicast data packets according to the sixth embodiment of the present invention. In the sixth embodiment, as an operation example 2 of the multicast data packet retransmission control operation performed in the multicast data packet transmission system shown in FIG. 14, the retransmission control table is set as the transmission reason of the status notification message from the receiving station to the transmitting station. The multicast data packet retransmission control operation in the case where an unconditional request for retransmission is included regardless of the setting value of is shown. Note that, in FIG. 17, each receiving station is supposed to perform transmission of the status notification message to the transmitting station using the uplink common channel. Further, also in the sixth embodiment, the message and the retransmission control table shown in FIGS. 7, 15, 25 and 26 are similarly used.

In FIG. 17, the transmitting station 1a determines the transmission interval.
4 RLC-PDUs (Seq.No = 0,1,2,3) during TTI-0 period
300a is transmitted. The receiving station 2a receives the next transmission interval TTI-
RLC-PDU in protocol processing 110-5a executed in 1
In reception processing, four RLC-PDUs (Seq.No = 0,1,2,3) 3 transmitted by the transmitting station 1a during the transmission interval TTI-0 3
00a, one RLC-PDU (Seq.No = 1) 300a has been detected as missing (SN = 1 missing), so the STATUS-PDU (200-5a) 310-2 requesting retransmission is sent next. Create as follows.

Also in the receiving station 2b, in the RLC-PDU receiving process in the protocol process 110-5b executed at the same transmission interval TTI-1, the four RLCs transmitted by the transmitting station 1a during the transmission interval TTI-0. -PDU (Seq.No = 0,1,2,3) 300
Among the a, two RLC-PDUs (Seq.No = 1,2) 300a are detected as missing (SN = 1, 2 missing), and therefore STATUS-PDU (200-5b) 310 requesting retransmission. -2 is created as follows.

That is, STATUS-PDU (200-5a) 3
10-2 and STATUS-PDU (200-5b) 310-2 include “LSN” 412 in FIGS. 7, 25 and 26.
Upper limit of the sequence number that was successfully received ("VTM
The value next to “3” (described as “s”) (the sequence number expected to be received next) “4” is set. "SN" 424
A sequence number “1” at the beginning of the RLC-PDU 300a requesting retransmission is set. “L” 425 includes receiving station 2
The subsequent number “0” is set in the STATUS-PDU (200-5a) 310-2 of a, and the STATUS-PDU (200-200-
5b) In 310-2, the subsequent number "1" is set. The transmission reason “Cause” 315 includes STATU of the receiving station 2a.
In S-PDU (200-5a) 310-2, "Miss" indicating "missing detection of transmission sequence number 302" is set,
In the STATUS-PDU (200-5b) 310-2 of the receiving station 2b, "Miss-A" indicating "unconditional retransmission request" is set.

Both the receiving stations 2a and 2b request the transmitting station 1a to retransmit, and therefore, the STATUS-PDU (20 having the above-mentioned contents during the period of the next transmission interval TTI-2.
0-5a) 310-2, STATUS-PDU (200-5b) 3
Try to transmit 10-2 on the uplink common channel. That is, the acquisition control of the access right to the uplink common channel is executed. As a result, the receiving station 2a acquires the transmission right, and during the period of the transmission interval TTI-2, the STATUS-PDU (200-5
a) Transmit 310-2 on the uplink common channel. Also, the receiving station 2b acquires the right to transmit on the uplink common channel during the next transmission interval TTI-3, and the STATUS-PDU
(200-5b) 310-2 is transmitted on the uplink common channel.

The transmitting station 1a receives the STATUS-PDU received from the receiving station 2a in the STATUS-PDU receiving process in the protocol process 100-5 executed during the transmission interval TTI-3.
(200-5a) 310-2 to 1 RLC-PDU (Seq.No.
= 1) Recognize the retransmission request of 300a. As a result, the transmitting station 1a checks the retransmission control table 150 shown in FIG. 15 and requests the retransmission of the RLC-PDU 300a of Seq.No = 1.
Check the resend status of. The retransmission flag 153 for SN = 1 in SN 151 is “OFF”.

Therefore, the transmitting station 1a determines that the retransmission has not been performed, and prepares for the retransmission of the RLC-PDU 300a with Seq.No = 1. In the retransmission control table 150, the value of VTMt152 for SN = 1 in SN151 is set to the transmission interval TTI-3.
Upper limit value of the sequence number transmitted during the period
5 ”, and the retransmission flag 153 is set to the“ ON ”flag. Then, the transmitting station 1a downlinks the new RLC-PDU (Seq.No = 16,17,18) 300a together with the retransmitted RLC-PDU (Seq.No = 1) 300a during the next transmission interval TTI-4. Send using a multicast channel on the transmission path.

[0209] Further, the transmitting station 1a has the transmission interval TTI-
STA in protocol processing 101-5 executed in period 4
In the TUS-PDU reception process, the S received from the receiving station 2b
Two RLC-Ps from TATUS-PDU310-2 (200-5b)
Recognize the unconditional resend request of DU (Seq.No = 1,2) 300a. Therefore, the transmitting station 1a uses the retransmission control table 150
Is not checked, and the sequence number (S
Prepare to retransmit the RLC-PDU 300a with eq.No = 1, 2). In the retransmission control table 150, SN = SN 151
The value of VTMt 152 for each of 1 and 2 is set to the upper limit value “18” of the sequence number transmitted during the transmission interval TTI-4, and the “ON” flag is set to the retransmission flag 153.

Then, the transmitting station 1a sends the next transmission interval TTI-
In the period of 5, the new RLC-PDU (Seq.No = 19,20) 300a is transmitted together with the retransmitted RLC-PDU (Seq.No = 1,2) 300a using the multicast channel on the downlink transmission path. In the period of this transmission interval TTI-5, in the receiving station 2a, in the RLC-PDU receiving process in the protocol process 111-5a,
Se transmitted by the transmitting station 1a during the transmission interval TTI-4
Reception of RLC-PDU 300a with q.No = 1 is confirmed (SN =
1 Resend confirmation). Similarly, in the receiving station 2b, in the RLC-PDU receiving process in the protocol process 111-5b, Seq.No = 1 transmitted by the transmitting station 1a during the transmission interval TTI-4.
Of the RLC-PDU 300a is confirmed (SN = 1 retransmission confirmation).

Further, in the receiving station 2b, the next transmission interval TTI-
R in protocol processing 112-5b to be executed during period 6
In the LC-PDU receiving process, the transmitting station 1a sets the transmission interval TTI-5.
No. of RLC-PDU300a with Seq.No = 1,2 transmitted during the period
Is confirmed to be received. RLC-PDU300a with Seq.No = 1
Since reception processing has been completed during the previous transmission interval TTI-5, in the RLC-PDU reception processing in the protocol processing 112-5b executed during this transmission interval TTI-6, the Seq whose reception was confirmed this time is confirmed. The RLC-PDU 300a with No. 1 is discarded. That is, the retransmission of SN = 2 is confirmed.

As described above, according to the sixth embodiment,
The transmitting station that transmits the multicast data packet responds to the retransmission request notified by multiple receiving stations in duplicate.
By using the retransmission control table corresponding to the multicast data packet, it is possible to prevent duplicate retransmissions, but do not use the retransmission control table for receiving stations that want to confirm delivery immediately. As a result, it is possible to perform retransmission without causing unnecessary delay.

Seventh Embodiment FIG. 18 is a sequence diagram illustrating a retransmission control method for multicast data packets according to the seventh embodiment of the present invention. In the seventh embodiment, as an operation example 3 of the multicast data packet retransmission control operation performed in the multicast data packet transmission system shown in FIG. 14, an uplink dedicated channel is used for transmitting a status notification message from the receiving station to the transmitting station. The multicast data packet retransmission control operation when used is shown. In addition, also in this Embodiment 7,
The messages and retransmission control tables shown in FIGS. 7, 15, 25 and 26 are used in the same manner.

In FIG. 18, the transmitting station 1a determines the transmission interval.
4 RLC-PDUs (Seq.No = 0,1,2,3) during TTI-0 period
300a is transmitted. The receiving station 2a receives the next transmission interval TTI-
RLC-PDU in protocol processing 110-6a executed in 1
In reception processing, four RLC-PDUs (Seq.No = 0,1,2,3) 3 transmitted by the transmitting station 1a during the transmission interval TTI-0 3
00a, one RLC-PDU (Seq.No = 1) 300a has been detected as missing (SN = 1 missing), so the STATUS-PDU (200-6a) 310-2 requesting retransmission is sent next. Create as follows.

Also in the receiving station 2b, in the RLC-PDU receiving process in the protocol process 110-6b executed at the same transmission interval TTI-1, the four RLCs transmitted by the transmitting station 1a during the transmission interval TTI-0. -PDU (Seq.No = 0,1,2,3) 300
Of the two a's, two RLC-PDUs (Seq.No = 1,2) 300a have been detected as missing (SN = 1, 2 missing), so STATUS-PDU (200-6b) 310 requesting retransmission. -2 is created as follows.

That is, STATUS-PDU (200-6a) 3
10-2 and STATUS-PDU (200-6b) 310-2, in FIG. 7, FIG. 25, and FIG.
e ”315 is set to“ detection of missing transmission sequence number 302 ”
“Miss” indicating is set. Upper limit value (VTMs) of the sequence number that was successfully received by the "LSN" 412
Next value of "3" (sequence number to expect next reception)
“4” is set. Request resend to “SN” 424
The first sequence number "1" of the RLC-PDU 300a is set. "L" 425 contains the STATUS-PDU of the receiving station 2a.
In (200-6a) 310-2, the subsequent number "0" is set, and STATUS-PDU (200-6b) 310- of the receiving station 2b is set.
In the case of 2, the subsequent number "1" is set.

The receiving stations 2a and 2b both receive the next transmission interval.
STATUS- having the above contents during the period of TTI-2
PDU (200-6a) 310-2, STATUS-PDU (200
-6b) 310-2 is transmitted on the uplink dedicated channel and requests the transmitting station 1a to retransmit. The transmitting station 1a uses the protocol processing 10 to be executed during the next transmission interval TTI-3.
In the reception process of STATUS-PDU in 0-6, the receiving station 2
Retransmission requests from a and 2b are recognized, and the necessity of retransmission is determined. Although this determination is in no particular order, here, the receiving station 2
It is assumed that judgment is made in the order of a and 2b.

That is, the transmitting station 1a first receives the receiving station 2
In the process of receiving the STATUS-PDU (200-6a) 310-2 from a, the retransmission request of one RLC-PDU (Seq.No = 1) 300a is recognized. As a result, the transmitting station 1a is
The retransmission control table 150 shown in FIG. 5 is checked to check the retransmission status of the RLC-PDU 300a with the Seq.No = 1 requested for retransmission. Retransmission flag 1 for SN = 1 in SN 151
53 is “OFF”.

Therefore, the transmitting station 1a determines that the retransmission has not been performed, and prepares for the retransmission of the RLC-PDU 300a with Seq.No = 1. In the retransmission control table 150, the value of VTMt152 for SN = 1 in SN151 is set to the transmission interval TTI-3.
Upper limit value of the sequence number transmitted during the period
5 ”, and the retransmission flag 153 is set to the“ ON ”flag.

Then, the transmitting station 1a receives from the receiving station 2b.
In the reception process of STATUS-PDU (200-6b) 310-2, the retransmission request of two RLC-PDUs (Seq.No = 1,2) is recognized. As a result, the transmitting station 1a checks the retransmission control table 150 shown in FIG.
Check the retransmission status of the RLC-PDU 300a of = 1 and 2. Seq.No = 1
For the RLC-PDU 300a of No. 1, the retransmission control table 15
The retransmission flag 153 for SN = 1 in SN 151 at 0 is “ON”.

That is, since it has been retransmitted, the value "15" of the VTMt 152 that has been set and the STATUS-PDU 310-2 from the receiving station 2b are checked in order to check the necessity of retransmission.
The value of VTMs set to (200-6b) is "3"
Compare the size with. Since VTMs <VTMt,
It is judged that retransmission is unnecessary and SN = 1 (RLC-PDU30 with Seq.No = 1
It does not prepare for retransmission of 0a) again.

However, for the RLC-PDU 300a with Seq.No = 2, the retransmission flag 153 for SN = 2 in SN151 is "OFF". Therefore, the transmitting station 1a
Determines that retransmission has not been performed, and RLC-PDU3 with Seq.No = 2
Prepare to retransmit 00a. In the retransmission control table 150, VTMt15 for SN = 2 in SN151
The value of 2 is set to the upper limit value “15” of the sequence numbers transmitted in the period of the transmission interval TTI-3, and the retransmission flag 15 is set.
Set the “ON” flag to 3.

Then, the transmitting station 1a sends the next transmission interval TTI-
In the period of 4, with retransmission RLC-PDU (Seq.No = 1,2),
The new RLC-PDU (Seq.No = 16,17) is transmitted using the multicast channel on the downlink transmission path. As a result, in the next transmission interval TTI-5, in the receiving station 2a, in the RLC-PDU receiving process in the protocol process 111-6a, the Seq. = 1,2 RLC-PDU300a, Seq.No = 2 RLC
-PDU300a is discarded and Req-PDU30 with Seq.No = 1
Reception of 0a is confirmed (SN = 1 retransmission confirmation). Similarly, in the receiving station 2b, the protocol processing 111-6b
In the RLC-PDU reception process, the transmitting station 1a transmits the transmission interval TTI-4.
No. of RLC-PDU300a with Seq.No = 1,2 transmitted during the period
Is confirmed (SN = 1, 2 retransmission confirmation).

As described above, according to the seventh embodiment,
The transmitting station that transmits the multicast data packet responds to the retransmission request notified by multiple receiving stations in duplicate.
By using the retransmission control table corresponding to the multicast data packet, duplicate retransmission can be suppressed. Therefore, it is possible to prevent wasteful consumption of resources on the downlink transmission path (wireless transmission path or wired transmission path).

Eighth Embodiment FIG. 19 is a sequence diagram for explaining a retransmission control method for multicast data packets according to the eighth embodiment of the present invention. In the eighth embodiment, as an operation example 4 of the multicast data packet retransmission control operation performed in the multicast data packet transmission system shown in FIG. 14, when the multicast data packet retransmitted from the transmitting station to the receiving station is lost again A multicast data packet retransmission control operation is shown. Note that, in FIG. 19, each receiving station is supposed to perform transmission of the status notification message to the transmitting station using the uplink dedicated channel. Further, also in the eighth embodiment, the message and the retransmission control table shown in FIGS. 7, 15, 25 and 26 are similarly used.

In FIG. 19, the transmitting station 1a determines the transmission interval.
4 RLC-PDUs (Seq.No = 2010,201) during TTI-m0 period
1, 2012, 2013) 300a is transmitted. The receiving station 2a uses the protocol processing 110-7 to be executed at the next transmission interval TTI-m1.
In the RLC-PDU reception process at a, the four RLC-PDUs (Seq.No.) sent by the transmitting station 1a during the transmission interval TTI-m0
= 2010,2011,2012,2013) One RLC-PDU out of 300a
(Seq.No = 2011) Missing of 300a is detected (SN = 201
1 omission detected), so STATUS-PDU requesting retransmission
(200-7a) 310-2 is created as follows.

That is, STATUS-PDU (200-7a) 3
In FIG. 10, FIG. 25, and FIG. 26, 10-2 is set to “Miss” indicating “missing detection of transmission sequence number 302” as the transmission reason “Cause” 315. "LSN" 41
2, the upper limit of the sequence number that was successfully received (VTM
s) The next value of "2013" (sequence number expected to be received next) "2014" is set. The sequence number “201” at the beginning of the RLC-PDU 300a requesting retransmission to the “SN” 424
1 ”is set. The subsequent number “0” is set in “L” 425.

[0228] The receiving station 2a requests the transmitting station to resend, so that the STATUS-PDU (200-7a) 310 having the above-mentioned contents is sent during the next transmission interval TTI-m2.
-2 is transmitted on the uplink dedicated channel, and the retransmission confirmation timer is started.

The transmitting station 1a receives the STATUS-PDU received from the receiving station 2a in the STATUS-PDU receiving process in the protocol process 100-7 executed in the period of the transmission interval TTI-m3.
(200-7a) 310-2 to 1 RLC-PDU (Seq.No.
= 2011) Recognize the retransmission request of 300a. by this,
The transmitting station 1a checks the retransmission control table 150 shown in FIG. 15, and requests the retransmission of the RLC-PDU 30 of Seq.No = 2011.
Check the retransmission status of 0a. SN = 2 in SN151
The retransmission flag 153 for 011 is “OFF”.

[0230] Therefore, the transmitting station 1a determines that the retransmission has not been performed, and prepares for the retransmission of the RLC-PDU 300a with Seq.No = 2011. In the retransmission control table 150, the value of the VTMt 152 for SN = 2011 in the SN 151 is set to the upper limit value “2025” of the sequence number transmitted in the period of the transmission interval TTI-m3, and the retransmission flag 153 is set to “O”.
The N "flag is set. Then, the transmitting station 1a retransmits RLC-PDU (Seq.No = 201) in the next transmission interval TTI-m4.
1) Together with 300a, new RLC-PDU (Seq.No = 2026,2027,202
8) Transmit 300a using the multicast channel on the downlink transmission path.

[0231] Here, the receiving station 2 receives the RLC-PDU (SN = 2011) 300a retransmitted by the transmitting station during the transmission interval TTI-m4.
It is assumed that a cannot be received correctly again. In the receiving station 2a, the timeout of the retransmission confirmation timer is recognized in the RLC-PDU receiving process in the protocol process 111-7a executed in the period of the transmission interval TTI-n1, and the retransmission is requested again.
STATUS-PDU (201-7a) 310-2 is created.

That is, this STATUS-PDU (201-7
a) 310-2, in FIG. 7, FIG. 25, and FIG.
The reason for transmission "Cause" 315 is "Transmission sequence number 30"
“Miss” indicating “2 missing detection” is set. "LS
A value (11) next to the upper limit value (“VTMs”) “10” of the sequence number that was normally received (N) 412 (the next expected sequence number) is set to “11”. "SN" 4
The beginning sequence number “2011” of the RLC-PDU 300a requesting retransmission is set to 24. The subsequent number “0” is set in “L” 425.

[0233] Then, the receiving station 2a requests the transmitting station to retransmit, and therefore, the STATUS-PDU (201-7) having the above-mentioned contents during the next transmission interval TTI-n2.
a) 310-2 is transmitted on the uplink dedicated channel and the retransmission confirmation timer is started. The transmitting station 1a receives the next transmission interval TTI-
STATUS-P in protocol processing 101-7 executed in n3
STATUS received from the receiving station 2a in the DU reception process
-One RLC-PDU (Se from PDU (201-7a) 310-2
(q.No = 2011) Recognize the retransmission request of 300a. As a result, the transmitting station 1a causes the retransmission control table 15 shown in FIG.
RLC-PDU of Seq.No = 2011, which is checked for 0 and requested to be retransmitted
Check the retransmission status of 300a.

The retransmission flag 153 for SN = 2011 in the SN 151 in the retransmission control table 150 is "O".
Since it is N ", the retransmission has already been performed.
In order to check the necessity of retransmission, the upper limit value VTMt set in the VTMt 152 in the retransmission control table 150 and ST
Upper limit value VTM from ATUS-PDU (201-7a) 310-2
s is compared. Since the sequence number has cycled,
VTMs = 2048 + 10, while VTMt =
2028, and VTMs> VTMt. That is, the transmitting station 1a uses the RLC-P of Seq.No = 2011 for which the retransmission is requested.
Prepare to retransmit DU 300a. Retransmission control table 150
Then, V corresponding to SN = 2011 in SN151
The value of TMt152 is set to the upper limit value "22" of the sequence number transmitted in the period of the transmission interval TTI-n3.

Then, the transmitting station 1a sends the next transmission interval TTI-
In the period of n4, the new RLC-PDU (Seq.No = 23,24,25) is transmitted together with the retransmission RLC-PDU (Seq.No = 2011) using the multicast channel on the downlink transmission path. Receiving station 2
a confirms the reception of the RLC-PDU (Seq.No = 2011) requested to be retransmitted first in the RLC-PDU reception process in the protocol process 112-7a executed in the period of the next transmission interval TTI-n5. (SN = 2011 retransmission confirmation), and the retransmission confirmation timer is stopped.

As described above, according to the eighth embodiment,
The transmitting station that transmits the multicast data packet responds to the retransmission request notified by multiple receiving stations in duplicate.
By using the retransmission control table corresponding to the multicast data packet, it is possible to suppress duplicated retransmissions, which wastes resources of the downlink transmission path (wireless transmission path or wired transmission path). Can be prevented. In addition, when the retransmitted multicast data packet is lost again or an error occurs, it can be retransmitted again, so that reliable multicast data packet transmission can be realized.

[Embodiment 9] 20 and 21 are flowcharts for explaining a multicast data packet retransmission control method according to the ninth embodiment of the present invention. The ninth embodiment shows a general multicast data packet retransmission control operation performed by the transmitting station, including the multicast data packet retransmission control operation described in the fifth to eighth embodiments. Hereinafter, FIG. 7, FIG. 16 to FIG.
Description will be made with reference to FIG. 26 as appropriate.

20 and 21, in the transmitting station, the packet (PDU) sent from the receiving station is checked (step ST30), and "D / C" 301 and "PDU" are checked.
Whether or not the status notification message is received is determined by "-Type" 311 (step ST31). When the status notification message is not received, the determination result is negative (step ST31: No), and the process proceeds to step ST49.
Data packet transmission processing (steps ST47, ST4
8) is executed. If the status notification message is received, the determination result is affirmative (step ST31: Y
es), the process proceeds to step ST32, and the retransmission control process (steps ST32 to ST44) is executed.

Retransmission control processing (steps ST32 to ST4)
4) will be described. In step ST32, the information necessary for the retransmission control is read from the received status notification message and held. That is, "Cause", "LSN-1", "SN", and "L" are read from the received status notification message, and "Cause" is retained as it is as "Cause", but "LSN-1" is "VTMs". , “SN” is held as “ReSN”, and “L” is held as “Len”.

Then, in step ST33, it is determined whether or not the transmission reason "Cause" of the status notification message is "unconditional retransmission". In the case of "unconditional retransmission" (step ST33: Yes), the process proceeds to step ST34. On the other hand, if it is not “unconditional retransmission” (step ST33:
No), and proceeds to step ST38.

In steps ST34 to ST37, a process of picking up all the multicast data packets (RLC-PDU) for which "unconditional retransmission" is requested is executed. That is, the top sequence number "ReSN" is held (step ST34), and the upper limit value "VTMt" corresponding to the sequence number "ReSN" in the retransmission control table is held.
And "retransmission flag" are set (step ST3).
5). Then, the next sequence number "ReSN" requested to be retransmitted by the status notification message is calculated (step ST36), and it is determined whether or not there is the next sequence number (step ST37). When there is the next sequence number (step ST37: Yes), step ST3
Returning to step 4, steps ST34 to ST37 are executed again.

[0242] In this way, the upper limit value "VTMt" and "retransmission flag" corresponding to each sequence number in the retransmission control table are set.
And are set (step ST35). When the setting of the retransmission control table is completed for all the multicast data packets (RLC-PDU) for which "unconditional retransmission" is requested in the status notification message (step ST37: No), the process proceeds to step ST46 and holds the sequence number. A retransmission data packet (PDU) is prepared from “ReSN”, and a transmission process (steps ST47 and ST48) including a newly transmitted data packet (PDU) transmitted from an upper layer (steps ST47 and ST48) is executed. To be done.

On the other hand, in the determination processing of step ST33, when the transmission reason "Cause" of the status notification message is not "unconditional retransmission" (step ST33: No),
In step ST38, retransmission control using the retransmission control table (steps ST38 to ST44) is performed.

At step ST38, the upper limit value "V" of the retransmission control table corresponding to the sequence number "ReSN" of the data packet requested to be retransmitted by the status notification message.
"TMt" and "retransmission flag" are read out and held. Then, in step ST39, it is determined whether the "retransmission flag" for the sequence number is set to the "ON" flag or the "OFF" flag. When the "retransmission flag" for the sequence number is not the "ON" flag (step ST39: N
o), that is, if retransmission has not been performed so far, the process proceeds to step ST41, and the sequence number “R
eSN "is retained for retransmission, and in step ST42,
The upper limit value “VTMt” of the corresponding retransmission control table is set, the “ON” flag is set in the “retransmission flag”, and the process proceeds to step ST43.

On the other hand, in the judgment processing of step ST39, when the "ON" flag is set in the "retransmission flag" for the sequence number "ReSN" (step ST39: Yes), that is, the retransmission is executed so far. If so, the process proceeds to step ST40 and the upper limit value “VTMs” calculated from the “LSN” included in the status notification message and the upper limit value “VTM” set in the retransmission control table corresponding to the sequence number “ReSN”.
"t" is compared in magnitude. When VTMs is larger than VTMt (step ST40: Yes), the state notification message indicates that the state notification message is created after receiving the data packet transmitted after the time when the transmitting station retransmits, and the sequence concerned. Since it is necessary to retransmit the number, the process proceeds to step ST41.

If VTMs is equal to or lower than VTMt in the judgment processing of step ST40 (step ST40).
40: No), the status notification message indicates that it was created before the time when the transmitting station retransmits, and since it is passing the retransmission of the sequence number, no retransmission is performed, and the process proceeds to step ST43. move on. Step ST43
Then, the next sequence number is calculated. As a result, it is determined whether or not there is the next sequence number "ReSN" (step ST44). Next sequence number "ReS
If there is "N" (step ST44: Yes), the process returns to step ST38, and the processes of steps ST38 to ST43 are similarly performed for the next sequence number "ReSN".

In the determination processing of step ST44, if there is no next sequence number "ReSN" (step S
T44: No), that is, the multicast data packet (RLC-PD) requested to be retransmitted by the status notification message.
When the process of determining the necessity of retransmission for all of U) is completed,
It is determined whether there is a data packet (PDU) to be retransmitted (step ST45). If there is a data packet (PDU) to be retransmitted (step ST45: Ye
s), in steps ST46 to ST48, the transmission process including the data packet to be newly transmitted is executed.

In the determination processing of step ST45, if there is no data packet (PDU) to be retransmitted (step ST45: No), step ST49.
At, new data packet (PDU) from upper layer
Will be sent. When a new data packet (PDU) is sent (step ST49:
Yes), in steps ST47 and ST48, the transmission processing of the data packet to be newly transmitted including the retransmission data packet, if any, is executed. If no new PDU is sent from the upper layer (step ST4
9: No), and the process is ended as it is. In the retransmission control table, the “ON” flag set in the “retransmission flag” is reset to “OF” when a new data packet (PDU) having the same sequence number is transmitted.
The F "flag is set.

As described above, according to the ninth embodiment, the transmitting station transmitting the multicast data packet sets the retransmission control table corresponding to the multicast in response to the retransmission request notified from a plurality of receiving stations in duplicate. By using it, it is possible to prevent redundant retransmissions, and thus it is possible to prevent wasteful consumption of resources on the downlink transmission path (wireless transmission path or wired transmission path).

[0250]

As described above, according to the present invention, in the data packet transmitting device, when the status notification message is received from the receiving side, the judging means first judges whether or not the retransmission control table exists. It As a result, if the retransmission control table exists, the retransmission control table is referred to by the determination means, and the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table, The difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, it is possible to effectively suppress the unnecessary retransmission due to the retransmission request received at the same time as the retransmission, and it is possible to perform only the truly necessary retransmission.

According to the next invention, in the data packet transmission device according to the above invention, when the retransmission control table exists, the deleting unit refers to the retransmission control table and includes the sequence number included in the status notification message. When the upper limit value exceeds the upper limit value of the sequence number included in the retransmission control table, the retransmission control table is deleted.
With this, an unnecessary table can be deleted when the retransmission is successful or when the retransmission fails and a new table is needed.

According to the next invention, in the data packet transmission device, the counter is incremented each time a status notification request message requesting the reception side to send a status notification message is transmitted, and the request number adding means causes the counter to increment. Is added as a request number to the status notification request message transmitted above. When the status notification message is received, the determination means first determines whether or not there is a retransmission control table. As a result, when the retransmission control table exists, the retransmission control table is referred to by the determination means, and when the sequence number upper limit value included in the status notification message and the retransmission control table match, the status notification message is displayed. When the status notification request message is received from the transmitting station and the request number included in the status notification message is less than or equal to the request number included in the retransmission control table, or the status notification message is sent using the periodic timer. When the transmission reason is a timeout and the transmission reason does not match the transmission reason included in the retransmission control table, or when the transmission reason of the status notification message is not the reception of the status notification request message from the transmitting station and the timeout of the periodic timer , The data packet included in the retransmission control table and status notification message. Difference information is extracted about, necessity of retransmission is determined.
Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, under the situation where the sequence numbers of the data packets to be transmitted are the same, it is possible to effectively suppress unnecessary retransmission due to the retransmission request and the retransmission request received at the same time. Can only be carried out.

According to the next invention, in the data packet transmission device, when the retransmission control table exists, the deleting means refers to the retransmission control table, and the upper limit value of the sequence number included in the status notification message is used for the retransmission control. When the sequence number upper limit value included in the table matches, the request number included in the status notification message is larger than the request number included in the retransmission control table, or the reason for sending the status notification message is the periodic timer. When it is time-out and the transmission reason matches the transmission reason included in the retransmission control table, the retransmission control table is deleted. This makes it possible to delete an unnecessary table in a situation where the sequence number of the data packet to be transmitted is the same, when the retransmission succeeds or the retransmission fails and a new table is needed.

According to the next invention, in the data packet transmission device, when the retransmission control table does not exist, when it is decided to perform the retransmission, the table setting means receives the data by the time of determining the retransmission process execution. The upper limit value of the sequence number of the data packet transmitted to the side and the request number and the transmission reason read from the status notification message and the information regarding the data packet to be transmitted are set, if applicable, and then the retransmission control is performed by the retransmission means. Based on the information about the data packet to be transmitted set in the table, the data packet is retransmitted. As a result, appropriate retransmission control can be performed using the retransmission control table.

According to the next invention, in the data packet receiving device, when the cause of transmission of the status notification message occurs, whether the status notification request message is received or the error is detected by the transmission reason creating means, A transmission reason indicating whether the cycle timer has timed out is created, and when the created transmission reason and the transmission reason are the reception of a status notification request message, the transmission reason adding means reads from the received status notification request message. And the request number are added to the status notification message and transmitted to the data packet transmission device. As a result, even when a data packet having the same sequence number is transmitted, retransmission control can be correctly performed in the data packet transmission device.

According to the next invention, in the data packet transmission device in the data packet transmission system, when the status notification message is received, the determination means first determines whether or not the retransmission control table exists. As a result, when the retransmission control table exists, the retransmission control table is referred to by the determination means, and the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table, The difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, it is possible to effectively suppress unnecessary retransmission due to the retransmission request and the retransmission request received in passing.
Only the truly necessary retransmissions can be performed.

According to the next invention, in the data packet transmission device in the data packet transmission system, when the retransmission control table exists, the deleting unit refers to the retransmission control table and includes the sequence number included in the status notification message. When the upper limit value exceeds the upper limit value of the sequence number included in the retransmission control table, the retransmission control table is deleted. As a result, if the resend succeeds or if the resend fails and a new table is needed,
You can delete unnecessary tables.

According to the next invention, in the data packet transmission device in the data packet transmission system, the counter is incremented each time the status notification request message requesting the reception side to send the status notification message is sent, and the request number is added. The count value of the counter is added as a request number to the status notification request message transmitted by the means. When the status notification message is received, the determination means first determines whether or not there is a retransmission control table. As a result, when the retransmission control table exists, the retransmission control table is referred to by the determination means, and when the sequence number upper limit value included in the status notification message and the retransmission control table match, the status notification message is displayed. When the request number included in is less than or equal to the request number included in the retransmission control table, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, Alternatively, when the reason for transmitting the status notification message is neither reception of the status notification request message from the transmitting station nor timeout of the periodic timer, the difference between the information on the data packets included in the retransmission control table and the status notification message is extracted. Then, the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, under the situation where the sequence numbers of the data packets to be transmitted are the same, it is possible to effectively suppress the unnecessary retransmission due to the retransmission request that was received due to the execution of the retransmission required, which is truly necessary. Only retransmission can be performed.

According to the next invention, in the data packet transmission device in the data packet transmission system, the retransmission control table is referred to by the deleting means when the retransmission control table exists, and the status notification message and the retransmission control table are transmitted. If the upper limit value of the sequence numbers included in the status notification message matches, the request number included in the status notification message is greater than the request number included in the retransmission control table, or the reason for sending the status notification message is that the periodic timer has timed out. Yes When the transmission reason matches the transmission reason included in the retransmission control table, the retransmission control table is deleted. This makes it possible to delete an unnecessary table in a situation where the sequence number of the data packet to be transmitted is the same, when the retransmission succeeds or the retransmission fails and a new table is needed.

According to the next invention, in the data packet transmission device in the data packet transmission system, when the retransmission control table does not exist, when it is decided to execute the retransmission, the table setting means executes the retransmission process. The upper limit value of the sequence number of the data packet transmitted to the receiving side by the time of determination and the request number and the information about the transmission reason read from the status notification message and the data packet to be transmitted, if applicable, are set, and then the retransmission means Then, the data packet is retransmitted based on the information about the transmitted data packet set in the retransmission control table. As a result, appropriate retransmission control can be performed using the retransmission control table.

According to the next invention, in the data packet receiving device in the data packet transmission system, when the cause of the transmission of the status notification message occurs, whether the transmission reason creating means receives the status notification request message,
A transmission reason is created whether it is an error detection or a periodic timer time-out, and the transmission reason addition means receives the created transmission reason and the transmission reason when the status notification request message is received. The request number read from the status notification request message is added to the status notification message and transmitted to the data packet transmitter. As a result, even when a data packet having the same sequence number is transmitted, retransmission control can be correctly performed in the data packet transmission device.

According to the next invention, in the data packet transmitting device, when the status notification message is received from the receiving side, the presence or absence of the retransmission control table is first judged in the judging step. As a result, when the retransmission control table exists, the retransmission control table is referenced in the determination step, and the sequence number upper limit value included in the status notification message is less than the sequence number upper limit value included in the retransmission control table. The difference between the information about the data packets included in the retransmission control table and the status notification message is extracted, and the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, it is possible to effectively suppress the unnecessary retransmission due to the retransmission request received at the same time as the retransmission, and it is possible to perform only the truly necessary retransmission.

According to the next invention, in the data packet transmission device, when the retransmission control table exists, the retransmission control table is referred to in the deleting step, and the upper limit value of the sequence number included in the status notification message is used for the retransmission control. When the sequence number upper limit value included in the table is exceeded, the retransmission control table is deleted. With this, an unnecessary table can be deleted when the retransmission is successful or when the retransmission fails and a new table is needed.

According to the next invention, in the data packet transmitting device, the counter is incremented each time the status notification request message requesting the data packet receiving device to send the status notification message is transmitted, and the step of adding the request number is performed. The count value of the counter is added as a request number to the status notification request message to be transmitted. When the status notification message is received, the presence or absence of the retransmission control table is first determined in the determination step. As a result, if the retransmission control table exists, the retransmission control table is referenced in the determination step, and if the sequence number upper limit value included in the status notification message and the retransmission control table match, the status notification message is displayed. When the request number included in is less than or equal to the request number included in the retransmission control table, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, Alternatively, when the reason for transmitting the status notification message is neither reception of the status notification request message from the transmitting station nor timeout of the periodic timer, the difference in information regarding the data packets included in the retransmission control table and the status notification message is extracted. Then, the necessity of retransmission is determined. Specifically, if there is no difference, it will not be retransmitted because it is waiting for the delivery confirmation of the data packet that has already been retransmitted.If there is a difference, it is determined that the data packet related to the difference will be retransmitted. To be done. Therefore, under the situation where the sequence numbers of the data packets to be transmitted are the same, it is possible to effectively suppress unnecessary retransmission due to the retransmission request and the retransmission request received at the same time. Can only be carried out.

According to the next invention, in the data packet transmission device, when the retransmission control table exists, the retransmission control table is referred to in the deletion step, and the sequence number included in the status notification message and the retransmission control table is included. If the upper limit values match, when the request number included in the status notification message is larger than the request number included in the retransmission control table, or the reason for sending the status notification message is that the periodic timer has timed out and the reason for sending is When the reason for transmission included in the retransmission control table matches, the retransmission control table is deleted. This makes it possible to delete an unnecessary table in a situation where the sequence number of the data packet to be transmitted is the same, when the retransmission succeeds or the retransmission fails and a new table is needed.

According to the next invention, in the data packet transmitting device, when the retransmission control table does not exist, when it is decided to perform the retransmission, the data packet transmitting device receives the data by the retransmission setting execution decision in the table setting step. The upper limit value of the sequence number of the data packet transmitted to the side and the request number and the transmission reason read from the status notification message and information on the data packet to be transmitted are set if applicable, and then the retransmission control is performed in the retransmission step. Based on the information about the data packet to be transmitted set in the table, the data packet is retransmitted. As a result, appropriate retransmission control can be performed using the retransmission control table.

According to the next invention, when the cause of transmission of the status notification message occurs in the data packet receiving device, whether the status notification request message is received or an error is detected in the transmission reason creating step, A transmission reason for whether the periodic timer has timed out is created, and in the transmission reason adding step, if the created transmission reason and the transmission reason are the reception of a status notification request message, read from the received status notification request message. And the request number are added to the status notification message and transmitted to the data packet transmission device. As a result, even when a data packet having the same sequence number is transmitted, retransmission control can be correctly performed in the data packet transmission device.

According to the next invention, in the data packet transmitting device for transmitting the data packet by the multicast,
When the status notification message requesting retransmission is received, the content related to the corresponding sequence number in the retransmission control table is referred to based on the sequence number included in the status notification message. The retransmission of the multicast data packet having the sequence number is performed. Then, the table setting means sets, in the retransmission control table, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed in association with the sequence number of the retransmitted multicast data packet. In other words, the retransmission control table initially displays that the multicast data packet of the sequence number has not been retransmitted, but when the retransmission is performed, the retransmission implementation status is set and the retransmission has been performed. Is displayed. In this way, the retransmission control table stores information on the retransmission execution for the multicast data packet having the sequence number.

According to the next invention, in the data packet transmitting device for transmitting the data packet by the multicast,
In the above invention, when the content related to the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted, the receiving device included in the status notification message is normally transmitted. Only when the upper limit value of the sequence number of the received multicast data packet is larger than the upper limit value of the transmitted sequence number at the time of performing the retransmission set in the retransmission control table, Retransmission is performed for the multicast data packet of sequence number. This makes it possible to prevent unnecessary retransmission even if duplicate retransmission requests are made. Further, in the case of a resend request in the case of being lost again or having an error again, it is possible to reliably perform resending.

According to the next invention, in the data packet transmitting device for transmitting the data packet by the multicast,
In the above invention, when the transmission reason included in the status notification message is an unconditional retransmission request, the retransmission execution means causes the sequence number included in the status notification message regardless of the contents of the retransmission control table. Retransmission is performed for the multicast data packet of. With this, if you need to confirm delivery immediately,
Retransmission can be performed without causing unnecessary delay.

According to the next invention, in the data packet transmitting device for transmitting the data packet by the multicast,
In the above invention, when the new data packet having the same number as the sequence number already retransmitted in the retransmission control table is transmitted by the table reset means, a process for returning the content related to the sequence number to the non-retransmitted state is performed. . By this means, it is possible to smoothly carry out retransmission control that suppresses unnecessary retransmissions using the retransmission control table.

According to the next invention, in each data packet receiving device that receives a data packet by multicast, when transmitting a status notification message, the transmission reason creating means unconditionally sends the status notification message to be transmitted. A transmission reason for requesting retransmission and a transmission reason for requesting retransmission that is not unconditional are included. This allows each data packet receiving device to set an unconditional resend request as the transmission reason and send it when there is no data packet that needs to respond to the delivery confirmation as soon as possible. It will be possible to receive a resend and to promptly reply to the delivery confirmation.

According to the present invention, in the data packet transmission device in the data packet transmission system for transmitting / receiving the data packet by multicast, when the status notification message is received, the retransmission control is performed based on the sequence number included in the status notification message. When the content related to the corresponding sequence number in the table is referred to and the retransmission is not yet performed, the retransmission execution means performs the retransmission for the multicast data packet of the sequence number.
Then, the table setting means sets, in the retransmission control table, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed in association with the sequence number of the retransmitted multicast data packet. In other words, the retransmission control table initially displays that the multicast data packet of the sequence number has not been retransmitted, but when the retransmission is performed, the retransmission implementation status is set and the retransmission has been performed. Is displayed. In this way, the retransmission control table stores information on the retransmission execution for the multicast data packet having the sequence number.

According to the next invention, in the data packet transmission device in the data packet transmission system for transmitting / receiving the data packet by multicast, in the above invention, the retransmission control table referred to based on the sequence number included in the status notification message. When the content related to the corresponding sequence number has been retransmitted, the upper limit value of the sequence number of the multicast data packet normally received by the receiving device included in the status notification message is set in the retransmission control table. Only when it is larger than the upper limit value of the transmitted sequence number at the time of retransmitting, the retransmitting means retransmits the multicast data packet of the sequence number. This makes it possible to prevent unnecessary retransmission even if duplicate retransmission requests are made. Further, in the case of a resend request in the case of being lost again or having an error again, it is possible to reliably perform resending.

According to the next invention, in the data packet transmission device in the data packet transmission system for transmitting / receiving the data packet by multicast, in the above invention, the transmission reason contained in the status notification message is an unconditional retransmission request. In this case, the retransmitting means retransmits the multicast data packet having the sequence number included in the status notification message regardless of the content of the retransmission control table. As a result, when it is necessary to confirm the delivery immediately, the retransmission can be performed without causing an unnecessary delay.

According to the next invention, in the data packet transmission device in the data packet transmission system for transmitting / receiving the data packet by multicast, in the above invention, the table reset means causes the sequence in which the retransmission has been performed in the retransmission control table. When a new data packet having the same number as the number is transmitted, a process of returning the content related to the sequence number to the state where retransmission is not performed is performed. By this means, it is possible to smoothly carry out retransmission control that suppresses unnecessary retransmissions using the retransmission control table.

According to the next invention, in the data packet receiving device in the data packet transmission system for transmitting / receiving the data packet by multicast, in the above invention, when transmitting the status notification message, the transmission reason creating means, It is performed that the status notification message to be transmitted includes a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting unconditional retransmission. This allows each data packet receiving device to set an unconditional resend request as the transmission reason and send it when there is no data packet that needs to respond to the delivery confirmation as soon as possible. It will be possible to receive a resend and to promptly reply to the delivery confirmation.

According to the present invention, when a data packet transmitting / receiving device receives a status notification message requesting retransmission when transmitting / receiving a data packet by multicasting, the sequence number included in the status notification message is used. Based on this, the content related to the corresponding sequence number in the retransmission control table is referred to, and when retransmission has not been performed, retransmission is performed for the multicast data packet of the sequence number in the retransmission step. Then, in the table setting step, the upper limit value of the sequence numbers already transmitted at the time when the retransmission is performed is set in the retransmission control table in association with the sequence number of the retransmitted multicast data packet. In other words, the retransmission control table initially displays that the multicast data packet of the sequence number has not been retransmitted, but when the retransmission is performed, the retransmission implementation status is set and the retransmission has been performed. Is displayed. In this way, the retransmission control table stores information on the retransmission execution for the multicast data packet having the sequence number.

[0279] According to the next invention, in the above invention, in the data packet transmitting device, when the status notification message requesting retransmission is received, the retransmission control referred to based on the sequence number included in the status notification message. When the content regarding the corresponding sequence number in the table has been retransmitted, the upper limit value of the sequence number of the multicast data packet included in the status notification message which is normally received by the receiving device is set in the retransmission control table. Retransmission is performed for the multicast data packet of the sequence number only in the case of being larger than the upper limit value of the transmitted sequence number at the time of performing the retransmission. This makes it possible to prevent unnecessary retransmission even if duplicate retransmission requests are made. Further, in the case of a resend request in the case of being lost again or having an error again, it is possible to reliably perform resending.

According to the next invention, in the above invention, when the data packet transmission device receives the status notification message requesting retransmission, the transmission reason included in the status notification message is checked, and the transmission reason is When the request is an unconditional retransmission request, the retransmission execution means retransmits the multicast data packet having the sequence number included in the status notification message regardless of the content of the retransmission control table. As a result, when it is necessary to confirm the delivery immediately, the retransmission can be performed without causing an unnecessary delay.

According to the next invention, in the above-mentioned invention, in the data packet transmitting device, when the new data packet having the same number as the sequence number already retransmitted in the retransmission control table is transmitted in the table reset step. A process of returning the content related to the sequence number to the state where the retransmission has not been performed is performed. By this means, it is possible to smoothly carry out retransmission control that suppresses unnecessary retransmissions using the retransmission control table.

According to the next invention, in the above invention, in each data packet receiving device for receiving the data packet by multicast, when transmitting the status notification message, the status notification to be transmitted is transmitted in the transmission reason creating step. It is performed to include a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting non-conditional retransmission. This allows each data packet receiving device to set an unconditional resend request as the transmission reason and send it when there is no data packet that needs to respond to the delivery confirmation as soon as possible. It will be possible to receive a resend and to promptly reply to the delivery confirmation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a data packet transmission system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a transmitting station shown in FIG.

3 is a diagram showing a format example of a data packet transmitted by the transmitting station shown in FIG.

FIG. 4 is a diagram showing a configuration example of a retransmission control table provided for retransmission control by the transmitting station shown in FIG.

5 is a block diagram showing a configuration of a receiving station shown in FIG.

6 is a diagram showing a format example of a status notification message transmitted by the receiving station shown in FIG. 1 in response to reception of a status notification request message.

FIG. 7 is a diagram showing a format example of a status notification message transmitted when the receiving station shown in FIG. 1 detects a missing sequence number or when the cycle timer times out.

8 is a sequence diagram illustrating a data packet retransmission control operation performed in the data packet transmission system shown in FIG.

FIG. 9 is a sequence diagram illustrating a data packet retransmission control method according to the second embodiment of the present invention.

FIG. 10 is a sequence diagram illustrating a data packet retransmission control method that is Embodiment 3 of the present invention.

FIG. 11 is a flowchart explaining a data packet retransmission control method according to the fourth embodiment of the present invention (No. 1).

FIG. 12 is a flowchart explaining a data packet retransmission control method according to the fourth embodiment of the present invention (No. 2).

FIG. 13 is a flowchart explaining the data packet retransmission control method according to the fourth embodiment of the present invention (No. 3).

FIG. 14 is a block diagram showing a configuration of a multicast data packet transmission system according to a fifth embodiment of the present invention.

15 is a diagram showing a configuration example of a retransmission control table provided for retransmission control by the transmitting station shown in FIG.

16 is a sequence diagram illustrating a retransmission control operation of a multicast data packet performed in the multicast data packet transmission system shown in FIG. 14 (using an uplink common channel for transmission of a status notification message from a receiving station to a transmitting station). If you do).

FIG. 17 is a sequence diagram for explaining a retransmission control method for multicast data packets according to the sixth embodiment of the present invention (in the case where an uplink common channel is used for transmitting a status notification message from a receiving station to a transmitting station, If the transmission reason includes an unconditional resend request).

FIG. 18 is a sequence diagram for explaining a retransmission control method for multicast data packets according to the seventh embodiment of the present invention (when an uplink dedicated channel is used for transmitting a status notification message from a receiving station to a transmitting station).

FIG. 19 is a sequence diagram for explaining a retransmission control method for multicast data packets according to the eighth embodiment of the present invention.

FIG. 20 is a flowchart explaining a retransmission control method for multicast data packets according to the ninth embodiment of the present invention (No. 1).

FIG. 21 is a flowchart explaining a retransmission control method for multicast data packets according to the ninth embodiment of the present invention (No. 2).

FIG. 22 is a sequence diagram illustrating a conventional data packet retransmission control method.

FIG. 23 is a diagram showing a format example of a data packet transmitted by the transmitting station according to the conventional and fifth embodiments.

FIG. 24 is a diagram showing a format example of a status notification message transmitted by the receiving station according to the related art and the first embodiment.

[Fig. 25] Fig. 25 is a diagram illustrating a format example of a delivery confirmation information element included in a status notification message transmitted by a receiving station.

FIG. 26 is a diagram showing a format example of a retransmission request information element included in a status notification message transmitted by the receiving station.

[Explanation of symbols]

1, 1a Transmitting station (data packet transmitting device) 2, 2
a, 2b, 2c receiving station (data packet receiving device),
3, 3a, 3b, 3c, 4a, 4b, 4c Transmission line, 1
1 Transmission PDU generation unit, 13 Poll Counter, 14 Retransmission determination unit, 15,150 Retransmission control table, 16 Message acceptance processing unit, 22 Sequence monitoring unit, 23
Cycle timer, 24 transmission reason creation unit, 25 status notification message creation unit, 300 data packet (RLC-PD
U), 300a Multicast data packet (RLC-P
DU), 306, 316, 401 Poll Counter, 310
-1,310-2 Status notification message (STATUS-PD
U), 315, 402 Cause, 403 VT (M), 4
04 LENGTH, 405-1 to 405-L SN _{1 to} SN _LENGT
H , 406-1 to 406-LL _{1 to} L _LENGTH , 410 Delivery confirmation information element, 420 Retransmission request information element, TTI-0 to TTI
-10, TTI-m0 to TTI-m4, TTI-n0 to TTI-n5 Transmission interval, V
TMt Upper limit value of sequence number set in retransmission control table, VTMs Upper limit value of sequence number set in status notification message.

Claims (33)

[Claims] 1. A status notification including the upper limit value of a sequence number of a received data packet and information about a data packet in which an error is detected from the receiving side in the process of transmitting a data packet with a sequence number to the receiving side. When a message is received, in the data packet transmitting device that retransmits the data packet in which the error is detected, when the status notification message is received from the receiving side,
A determination unit that determines whether or not a retransmission control table exists, and if the determination unit determines that a retransmission control table exists, the retransmission control table is referenced, and the upper limit sequence number included in the status notification message is used for the retransmission. When the sequence number is less than the upper limit of the sequence number included in the control table, a determination unit that extracts the difference between the information regarding the data packets included in the retransmission control table and the status notification message and determines whether retransmission is necessary is provided. A data packet transmission device characterized by the above. 2. The retransmission control table is referred to when the determining unit determines that the retransmission control table exists, and the upper limit of the sequence number included in the status notification message is the upper limit of the sequence number included in the retransmission control table. The data packet transmitting apparatus according to claim 1, further comprising a deleting unit that deletes the retransmission control table when the value exceeds the value. 3. A status notification including the upper limit value of the sequence number of the received data packet and information about the data packet in which an error is detected from the receiving side in the process of transmitting the data packet with the sequence number to the receiving side. When receiving the message, in a data packet transmitting device that retransmits the data packet in which the error is detected, a counter that counts the sequence number of the status notification request message requesting the transmission of the status notification message to the receiving side, Request number adding means for adding the count value of the counter as a request number when transmitting the status notification request message; and a judgment means for judging the presence or absence of a retransmission control table when the status notification message is received, The judgment means judges that the retransmission control table exists. When the status notification message and the upper limit value of the sequence numbers included in the retransmission control table match, the reason for transmitting the status notification message is the status notification request message from the transmitting station. Is received and the request number included in the status notification message is less than or equal to the request number included in the retransmission control table, or the reason for sending the status notification message is a timeout of a periodic timer and the reason for sending is the retransmission. When the transmission reason included in the control table does not match, or when the transmission reason of the status notification message is neither reception of the status notification request message from the transmitting station nor timeout of the periodic timer, the retransmission control table And the data packet included in the status notification message. A data packet transmitting apparatus, comprising: a determining unit that extracts a difference in information regarding a packet and determines whether retransmission is necessary. 4. When the judgment unit judges that there is a retransmission control table, the retransmission control table is referred to, and in the case where the sequence number upper limit values included in the status notification message and the retransmission control table match. When the request number included in the status notification message is greater than the request number included in the retransmission control table, or the reason for sending the status notification message is a timeout of a periodic timer, and the reason for sending is the retransmission control. The data packet transmitting apparatus according to claim 3, further comprising a deleting unit that deletes the retransmission control table when the transmission reason included in the table matches. 5. The upper limit value of the sequence number of the data packet transmitted to the receiving side by the time the decision is made to perform retransmission when it is decided by the decision means that the retransmission control table does not exist and retransmission is decided. And, if applicable, table setting means for creating the retransmission control table in which the request number, the transmission reason read from the status notification message, and information regarding the data packet to be retransmitted are set, and after the creation of the retransmission control table, 5. The retransmitting means for retransmitting the data packet based on the information about the data packet to be retransmitted, which is set in the retransmission control table, and a retransmitting means. Data packet transmitter. 6. When an error is detected in the process of receiving a data packet with a sequence number from the transmitting side, the upper limit value of the sequence number of the data packet received by the transmitting side and information on the data packet in which the error is detected. In a data packet receiving device for transmitting a status notification message including a message, the transmission cause of the status notification message is reception of a status notification request message, detection of an error, or timeout of a periodic timer. Transmission reason creating means for creating a reason, and when sending the status notification message, the sending reason created by the sending reason creating means and the status notification request received when the sending reason is reception of the status notification request message A transmission reason adding means for adding the request number read from the message, and Data packet receiving device. 7. A data packet receiving device for transmitting a status notification message including an upper limit value of a sequence number of a received data packet and information on a data packet in which an error is detected, and a data packet receiving device provided with a sequence number. In a data packet transmission system comprising: a data packet transmission device that retransmits a data packet whose error is detected based on the status notification message received in the process of transmitting a data packet, wherein the data packet transmission device is: When the status notification message is received, a judgment means for judging the presence or absence of a retransmission control table, and when the judgment means judges that the retransmission control table exists, the retransmission control table is referred to, and the status notification message is displayed. Sequence number upper limit included in When the value is less than the upper limit value of the sequence number included in the retransmission control table, a determination unit that determines the necessity of retransmission by extracting the difference between the information about the data packets included in the retransmission control table and the status notification message. A data packet transmission system comprising: 8. The data packet transmitting apparatus refers to the retransmission control table when the determining unit determines that the retransmission control table exists, and the upper limit value of the sequence number included in the status notification message is the retransmission control table. The data packet transmission system according to claim 7, further comprising a deleting unit that deletes the retransmission control table when the sequence number upper limit value included in the table is exceeded. 9. A data packet receiving device for transmitting a status notification message including an upper limit value of a sequence number of a received data packet and information regarding a data packet in which an error has been detected, and the data packet receiving device having a sequence number. In a data packet transmission system comprising: a data packet transmission device that retransmits a data packet whose error is detected based on the status notification message received in the process of transmitting a data packet, wherein the data packet transmission device is: A counter that counts the sequence number of a status notification request message that requests the data packet receiving device to send a status notification message, and a request number that adds the count value of the counter as a request number when sending the status notification request message With addition means When the status notification message is received, a determination unit that determines whether or not a retransmission control table exists, and a retransmission control table when the determination unit determines that the retransmission control table exists, refers to the status notification. When the message and the sequence number upper limit value included in the retransmission control table match, the transmission reason of the status notification message is the reception of the status notification request message from the transmitting station and the request included in the status notification message. When the number is less than or equal to the request number included in the retransmission control table, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, or , The reason for sending the status notification message is before the sending station. When the status notification request message is not received and the periodic timer is not timed out, the difference between the information related to the data packets included in the retransmission control table and the status notification message is extracted to determine whether retransmission is necessary. A data packet transmission system comprising: 10. The data packet transmission device refers to the retransmission control table when the determination unit determines that the retransmission control table exists, and a sequence number included in the status notification message and the retransmission control table. In the case where the upper limit values match, when the request number included in the status notification message is larger than the request number included in the retransmission control table,
Alternatively, when the transmission reason of the status notification message is a timeout of a periodic timer and the transmission reason matches the transmission reason included in the retransmission control table, a deletion unit for deleting the retransmission control table is provided. The data packet transmission system according to claim 9. 11. The sequence of data packets transmitted to the data packet receiving device by the time the decision is made to perform retransmission when it is decided by the decision means that a retransmission control table does not exist and retransmission is to be carried out. Table setting means for creating the retransmission control table in which the number upper limit value and, if applicable, the request number, the transmission reason read from the status notification message, and information regarding the data packet to be retransmitted are created, and the creation of the retransmission control table 11. A re-transmission unit which re-transmits the data packet based on the information about the data packet to be re-transmitted set in the re-transmission control table, which is provided later. The data packet transmission system described in. 12. The data packet receiving device creates a transmission reason whether the transmission cause of the status notification message is reception of a status notification request message, detection of an error, or timeout of a periodic timer. And a transmission reason creating unit that, when transmitting the status notification message, reads the transmission reason created by the transmission reason creating unit and the received status notification request message when the transmission reason is reception of the status notification request message. 12. The data packet transmission system according to any one of claims 8 to 11, further comprising: a transmission reason adding unit that adds the request number. 13. An upper limit value and an error of a sequence number of a received data packet are detected from the data packet receiving device while the data packet transmitting device is transmitting a data packet with a sequence number to the data packet receiving device. In a data packet retransmission control method, when receiving a status notification message including information regarding a data packet that has been transmitted, the data packet retransmission control method that retransmits a data packet in which an error is detected, wherein the data packet transmission device receives the status notification message. In the case where the retransmission control table is present, a determination step is performed, and when the determination step determines that the retransmission control table exists, the retransmission control table is referenced to determine the upper limit of the sequence number included in the status notification message. The value whose value is included in the retransmission control table. When the number is less than the upper limit value of the sequence number, a determination step of determining the necessity of retransmission by extracting the difference between the information related to the data packets included in the retransmission control table and the status notification message, and Packet retransmission control method. 14. When the determination step determines that a retransmission control table exists, the retransmission control table is referenced, and the upper limit value of the sequence number included in the status notification message is the upper limit of the sequence number included in the retransmission control table. The data packet retransmission control method according to claim 13, further comprising a deletion step of deleting the retransmission control table when the value is exceeded. 15. An upper limit value and an error of the sequence number of the received data packet are detected from the data packet receiving device while the data packet transmitting device is transmitting the data packet with the sequence number to the data packet receiving device. In a data packet retransmission control method for retransmitting a data packet in which an error is detected, when a status notification message including information regarding a data packet that has been transmitted is received, the data packet transmission device is A request number adding step of adding a count value of a counter for counting the sequence number of the status notification request message requesting transmission of the status notification message to the status notification request message as a request number, and transmitting the request packet; Status notification message When it is received, a determination step of determining the presence or absence of a retransmission control table, and when the determination step determines that a retransmission control table exists, the retransmission control table is referenced, and the status notification message and the retransmission control table are referenced. When the sequence number upper limit values included in and match, the reason for transmitting the status notification message is the reception of the status notification request message from the transmitting station, and the request number included in the status notification message is the retransmission control table. Or less than the request number, or when the transmission reason of the status notification message is the timeout of the periodic timer and the transmission reason does not match the transmission reason included in the retransmission control table, or the status notification message The reason for transmission is that the status notification request message from the transmitting station is received. When the transmission is not received and the period timer is not timed out, a determination step of determining a necessity of retransmission by extracting a difference between information regarding data packets included in the retransmission control table and the status notification message, A data packet retransmission control method characterized by the above. 16. When the retransmission control table is determined to exist by the determining step, the retransmission control table is referred to, and when the upper limit value of the sequence numbers included in the status notification message and the retransmission control table match. , When the request number included in the status notification message is larger than the request number included in the retransmission control table, or the reason for sending the status notification message is a timeout of a periodic timer and the reason for sending is the retransmission control. The data packet retransmission control method according to claim 15, further comprising a deletion step of deleting the retransmission control table when the transmission reason included in the table matches. 17. The upper limit value of the sequence number of the data packet transmitted to the receiving side by the time the retransmission process execution is determined, when it is determined that the retransmission control table does not exist in the determination step and the retransmission is determined to be performed. And, if applicable, a table setting step of creating the retransmission control table in which the request number, the transmission reason read from the status notification message, and information regarding the data packet to be retransmitted are set, and after the creation of the retransmission control table, The data retransmitting step according to any one of claims 13 to 16, further comprising: a retransmitting step of retransmitting the data packet based on information about the data packet to be retransmitted set in the retransmission control table. Packet retransmission control method. 18. The data packet receiving device sets a transmission reason as to whether the cause of transmitting the status notification message is reception of the status notification request message, detection of an error, or timeout of a periodic timer. A sending reason creating step to be created, and when sending the status notification message, when the sending reason created by the sending reason creating step and the sending reason are reception of a status notification request message, from the received status notification request message The data packet retransmission control method according to any one of claims 15 to 17, further comprising: a transmission reason adding step of adding the read request number. 19. Information regarding a multicast data packet in which the same data packet with a sequence number is multicast to a plurality of receiving devices and the upper limit value of the sequence number of the multicast data packet normally received from each receiving device and an error are detected. In a data packet transmission device that retransmits a multicast data packet in which the error is detected when receiving a status notification message including a message, a corresponding sequence number in the retransmission control table based on the sequence number included in the status notification message. Refer to the content of the above, and when the retransmission is not yet performed, the retransmission performing means for performing the retransmission of the multicast data packet of the sequence number, and the sequence number of the multicast data packet for which the retransmission is performed are associated with Data packet transmission apparatus being characterized in that and a table setting means for setting the retransmission control table the upper limit of the transmitted sequence number at the time of performing the retransmission Te. 20. When the content related to the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted, the receiving device included in the status notification message is normally operated. Only when the upper limit value of the sequence number of the received multicast data packet is larger than the upper limit value of the sequence number already transmitted at the time of performing the retransmission set in the retransmission control table, the multicast data packet of the sequence number 20. The data packet transmitting apparatus according to claim 19, further comprising: a retransmitting means for performing the retransmission. 21. When the transmission reason included in the status notification message is an unconditional retransmission request, the multicast data packet of the sequence number included in the status notification message is retransmitted regardless of the contents of the retransmission control table. 21. The data packet transmission device according to claim 19 or 20, further comprising: a re-execution executing unit. 22. When the new data packet having the same number as the sequence number that has been retransmitted in the retransmission control table is transmitted, table reset means is provided for performing processing for returning the content related to the sequence number to non-retransmission. 22. The data packet transmission device according to claim 19, wherein 23. When a missing sequence number or a data error is detected in the process of receiving a multicast data packet with a sequence number from the transmitting device, the upper limit of the sequence number of the received multicast data packet is sent to the transmitting device. In a data packet receiving device that transmits a status notification message including a value and information about a multicast data packet in which the error is detected, a transmission reason for unconditionally requesting retransmission of the status notification message to be transmitted and unconditional retransmission And a transmission reason creating means for including a transmission reason for requesting the data packet receiving apparatus. 24. A plurality of data packet receiving devices for transmitting a status notification message including an upper limit value of a sequence number of the received multicast data packet and information regarding the multicast data packet in which an error is detected, and the plurality of data packet receptions. Multicast the same data packet with a sequence number to the device,
A data packet transmission system comprising: a data packet transmission device that retransmits the multicast data packet in which the error is detected when receiving the status notification message from the plurality of data packet reception devices, wherein the data packet transmission device is , Referring to the contents regarding the corresponding sequence number of the retransmission control table based on the sequence number included in the status notification message, when the retransmission is not yet performed, a retransmission execution means for performing retransmission for the multicast data packet of the sequence number, Table setting means for setting, in the retransmission control table, the upper limit value of the sequence numbers already transmitted at the time of performing the retransmission in association with the sequence number of the multicast data packet for which the retransmission has been performed, When Data packet transmission system. 25. The data packet transmission device, when the content related to the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted, includes in the status notification message. Only when the upper limit value of the sequence number of the multicast data packet which the receiving device is normally received is larger than the upper limit value of the sequence number already transmitted at the time of performing the retransmission set in the retransmission control table, 25. The data packet transmission system according to claim 24, further comprising: resending execution means for resending a multicast data packet of the sequence number. 26. The data packet transmission device, when the transmission reason included in the status notification message is an unconditional retransmission request, the sequence number included in the status notification message regardless of the content of the retransmission control table. 26. The data packet transmission system according to claim 24 or 25, further comprising: resending execution means for resending the multicast data packet of. 27. The data packet transmitting device, when a new data packet having the same number as the sequence number for which retransmission has been performed in the retransmission control table is transmitted,
The data packet transmission system according to any one of claims 24 to 26, further comprising: a table reset unit that performs a process of returning the content related to the sequence number to a state where retransmission is not performed. 28. The data packet receiving device comprises transmission reason creating means for including, in the status notification message to be transmitted, a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting unconditional retransmission. The data packet transmission system according to any one of claims 24 to 27, wherein 29. The data packet transmission device multicasts the same data packet with a sequence number to a plurality of data packet reception devices, and the upper limit value and error of the sequence number of the multicast data packet normally received from the data packet reception device. In a data packet retransmission control method for retransmitting a multicast data packet in which the error is detected, when a status notification message including information regarding a detected multicast data packet is received, wherein the data packet transmission device is in the state Based on the sequence number included in the notification message, refer to the content related to the corresponding sequence number in the retransmission control table, and when retransmission has not been performed, retransmit the multicast data packet with that sequence number. And a table setting step of setting the upper limit value of the transmitted sequence number at the time of performing the retransmission in association with the sequence number of the retransmitted multicast data packet in the retransmission control table. A data packet retransmission control method comprising: 30. The data packet transmission device, when the content related to the corresponding sequence number of the retransmission control table referred to based on the sequence number included in the status notification message has been retransmitted, includes in the status notification message. Only when the upper limit value of the sequence number of the multicast data packet which the receiving device is normally received is larger than the upper limit value of the sequence number already transmitted at the time of performing the retransmission set in the retransmission control table, 30. The data packet retransmission control method according to claim 29, further comprising: a retransmission execution step of performing retransmission on the multicast data packet having the sequence number. 31. The data packet transmission device, when the transmission reason included in the status notification message is an unconditional retransmission request, the sequence number included in the status notification message regardless of the content of the retransmission control table. 31. The data packet retransmission control method according to claim 29 or 30, further comprising: a retransmission execution step of performing retransmission of the multicast data packet of. 32. The data packet transmitting device, when a new data packet having the same number as a sequence number for which retransmission has been performed in the retransmission control table is transmitted,
32. The data packet retransmission control method according to claim 29, further comprising a table reset step of performing a process of returning the content related to the sequence number to a state where retransmission has not been performed. 33. The data packet receiving device includes a step of including, in the status notification message to be transmitted, a transmission reason for unconditionally requesting retransmission and a transmission reason for requesting unconditional retransmission. 33. The data packet retransmission control method according to claim 29.