JP2001189730A - Device and method for packet communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce receiving buffers of a base station device and also to transmit a transmissible packet with less delay. SOLUTION: A processing part 101 performs SSCOP protocol processing of a packet received from a terminal device and generates a PDU, and a rate controlling part 102 transmits a packet obtained by the combination or the PDU surpassing one radio frame length to the base station device without exceed a transmission capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a transmission network of a mobile communication system and includes a communication protocol SSC described later.
The present invention relates to a packet communication device and method using a retransmission protocol such as OP (Service Specific Common Protocol).

[0002]

2. Description of the Related Art SSCOP is an IT system recommended by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).
U.T. This is a communication protocol specified in 2110.

In SSCOP, a data PDU (Protocol Data Unit) is used for communication of user data, and a control PDU is used for data delivery confirmation and line control confirmation. However,
The PDU is packet data.

FIG. 5 is a block diagram showing a configuration of a mobile communication system using a conventional packet communication device.

The mobile communication system shown in FIG. 5 includes a base station device 501, an HWY (highway) unit 502,
Packet communication device 503 and ADP (adapter) 504
And TCP / IP (Transmission Control Protocol / Int)
and a packet terminal 505 such as an Ethernet Protocol).

[0006] The packet communication device 503 uses ADP.
ATM (Asynchronous Tr)
ansfer Mode) transmission lines 506 and 507.

In such a configuration, the packet communication device 503 receives a packet transmitted from the packet terminal 505 via the ADP unit 504, performs SSCOP processing on the received packet, and then transmits the packet through the ATM transmission line 506. The HWY section 502 transmits the ATM cell to the base station apparatus 501 via the HWY section 502. Then, the base station apparatus 501 transmits a radio frame based on the ATM cell to the radio section 508.

Next, the configuration of the packet communication device 503 will be described with reference to FIG.

[0009] The packet communication device 503 includes an SSCOP protocol processing unit 601, a parameter management unit 602,
ATM communication LSI control unit 603 and reception processing unit 604
, A transmission processing unit 605, and an ATM communication LSI unit 606.

The SSCOP protocol processing unit 601 performs SSCOP processing on the packet received by the reception processing unit 604 and the packet from the packet terminal 505 transmitted via the ATM transmission line 506.

The parameter management unit 602 manages protocol variables, transmission speed, and radio frame length used in the SSCOP protocol.

[0012] The ATM communication LSI control unit 603
CBR (Constant Bit Rat)
e) By performing the setting, the setting is made so that the number of cells that can be transmitted within a certain period of time does not exceed the wireless speed and is not transmitted to the base station device 501.

The ATM communication LSI unit 606 decomposes the packet into ATM cells in accordance with the CBR speed set by the ATM communication LSI control unit 603,
7 and a process for assembling ATM cells received from the ATM transmission line 507 into packets.

In such a configuration, the packet communication device 503 sets the PD to a predetermined radio frame unit length.
Send U. Here, if the length is less than the wireless frame length, the base station device 501 pads the data to the insufficient amount, and transmits the data to the wireless section 508 with additional information such as a packet length and a CRC.

The operation of the packet communication device 503 will be described below. The transmission processing unit 605 that is notified of the wireless transmission rate used for communication from the parameter management unit 602 when setting the line.
Sets the transmission rate to the ATM communication LSI control unit 603.

The ATM communication LSI control unit 603 has an ATM
CBR (Constant Bit Rat)
e) By performing the setting, the setting is made so that the number of cells that can be transmitted within a certain period of time does not exceed the wireless speed and is not transmitted to the base station device 501.

The packet received from the packet terminal 505 on the wireless transmission path is sent to the SSCOP protocol processing unit 601.
, And notifies the transmission processing unit 605 of the PDU obtained by this processing.
Request transmission to the 5 ATM communication LSI unit 606.

The ATM communication LSI unit 606 decomposes the packet into ATM cells in accordance with the CBR speed set by the ATM communication LSI control unit 603,
Send to 7.

The reception processing unit 604 includes an ATM transmission line 507
The received ATM cell receives the packet assembled by the ATM communication LSI unit 606 and notifies the SSCOP protocol processing unit 601 as a PDU.

In response to this notification, the SSCOP protocol processing unit 601 executes the protocol processing and then transmits a packet to the packet terminal 505.

[0021]

However, in the conventional wireless rate control method, the ATM communication LSI unit 606 has a C
Rate control is performed by limiting the transmission band using the BR mode. This method is an ATM communication LSI
Since the unit 606 transmits at regular intervals while managing the number of cells to be transmitted per unit time, it is difficult to perform rate control in consideration of the radio frame length. This needs to be set in the communication LSI unit 606, and therefore, there is a problem that the base station device 501 must prepare a packet buffer having a large capacity.

The packet transmission is performed by an ATM communication LSI.
Since it depends on the cell transmission timing of the unit 606, the ATM
There is a problem that a waiting time from sending a transmission request to the communication LSI unit 606 to actually transmitting to the ATM transmission line 507 becomes long, and a propagation delay becomes large.

The present invention has been made in view of the above points, and it is possible to improve the packet transmission efficiency by effectively using a radio frame, reduce the number of reception buffers in a base station apparatus, and perform transmission. It is an object of the present invention to provide a packet communication device and method capable of transmitting a packet with less delay.

[0024]

A packet communication device according to the present invention uses an SSCO in packet data received from a terminal device.
A processing unit for performing P protocol processing to obtain transmission packet data; and a unit for determining whether or not packet data from the processing unit can be transmitted to the buffer in a buffer provided in the base station apparatus with a capacity corresponding to the wireless transmission capacity. Judgment is made for each time, and the packet data judged to be transmitted is transmitted,
A configuration is provided that includes a rate control unit that transmits packet data determined not to be transmitted within the next unit time.

According to this configuration, the propagation delay can be reduced, the base station device can be prevented from receiving data in bursts, and packet data can be transmitted in consideration of the radio frame length. Therefore, the buffer of the base station device can be made smaller than before.

[0026] In the packet communication device of the present invention, in the above configuration, the transmission packet data is decomposed into ATM cells and then transmitted to the base station device, and the ATM cells received from the base station device are assembled into packet data.
A configuration including communication processing means is employed.

According to this configuration, A
High-speed transmission by TM cells can be performed.

The base station controller of the present invention employs a configuration including a packet communication device having the same configuration as any of the above.

According to this configuration, in the base station controller, the same operation and effect as any of the above can be obtained.

The mobile communication system of the present invention employs a configuration including the base station control device having the above configuration.

According to this configuration, in the mobile communication system, the same operation and effect as those of the base station control device having the above configuration can be obtained.

According to the packet communication method of the present invention, it is determined whether or not packet data subjected to the SSCOP protocol processing can be transmitted to a buffer provided in a base station apparatus at a capacity corresponding to a radio transmission capacity at every unit time. Judge and send the packet data judged to be sent,
Packet data that cannot be transmitted is transmitted within the next unit time.

According to this method, the propagation delay can be shortened, the base station apparatus can be prevented from receiving data in bursts, and packet data can be transmitted in consideration of the radio frame length. Therefore, the buffer of the base station device can be made smaller than before.

[0034]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing a configuration of a packet communication apparatus according to an embodiment of the present invention.

However, the packet communication device 100 of the present embodiment shown in FIG. 1 is a conventional packet communication device 50 in the mobile communication system shown in FIG.
3 is provided at a position 3 and the mobile communication system according to the present embodiment will be described with reference to FIG. That is, the packet communication device 100
01 may be provided in the base station controller connected to the base station.

The packet communication device 100 shown in FIG.
SCOP protocol processing unit 101, rate control unit 10
2, a parameter management unit 103, an ATM communication LSI control unit 104, a timer processing unit 105, and a transmission processing unit 10.
6, an ATM communication LSI unit 107, and a reception processing unit 108
It is comprised including.

The SSCOP protocol processing unit 101
The PDU obtained by performing the SSCOP process on the packet from the packet terminal 505 transmitted via the TM transmission path 506 is output to the rate control unit 102. In the SSCOP process, however, user data is communicated using a data PDU, and data transmission confirmation and line control confirmation are performed using a control PDU.

The parameter management unit 103 notifies the rate control unit 102 of the radio frame length and the unit time, and notifies the timer processing unit 105 of the unit time.

Here, the unit time means a buffer provided in the base station device 501 for holding a transmission packet.
This is the time corresponding to the holding time from when the holding packet becomes 0 to full. The capacity of the buffer is the sum of the wireless transmission capacity and the transmission delay capacity.

The timer processing unit 105 measures time and notifies the rate control unit 102 that the unit time has been reached for each unit time notified from the parameter management unit 602.

The rate control unit 102 includes a rate control table 109 and a buffer (hereinafter referred to as a transmission queue) 119 for storing a packet obtained by performing queuing for connecting a plurality of PDUs from the SSCOP protocol processing unit 101. The packet stored in the transmission queue 119 according to the rate control table 109, or the SSCO
A PDU exceeding the length of one radio frame from the P protocol processing unit 101 is output to the transmission processing unit 106 within a unit time.

The rate control table 109 includes a transmission permitted PDU length 111, which is a constant indicating a PDU length that can be transmitted per unit time, and how many Ps after the unit time.
Transmittable PDU that is a variable indicating whether the DU length can be transmitted
Length 112, the number of transmission permitted PDUs 113 that is a constant indicating the number of PDUs that can be transmitted per unit time, and the number of transmittable PDUs 114 that indicates the number of PDUs that can be transmitted per unit time
And a transmission queue address 115 indicating the head address of the transmission queue 119.

The ATM communication LSI control unit 104 has an ATM
By performing the CBR setting for the communication LSI unit 107, the setting is made so that the number of cells that can be transmitted within a certain time exceeds the wireless speed and is not transmitted to the base station device 501.

The transmission processing unit 106 includes a rate control unit 102
Is output to the ATM communication LSI unit 107.

The ATM communication LSI unit 107 decomposes the packet into ATM cells in accordance with the CBR rate set by the ATM communication LSI control unit 104, transmits the packet to the ATM transmission line 507, and receives the packet from the ATM transmission line 507. It performs processing for assembling ATM cells into packets.

The reception processing unit 108 receives the packet assembled by the ATM communication LSI unit 107 and performs SSCOP
This is output to the protocol processing unit 101.

In such a configuration, a packet received from the packet terminal 505 via the ATM transmission line 506 is sent to the SSCOP protocol processing unit 101 by the SD-PD
After being converted to U (ordered data), the rate control unit 1
02 is output.

Also, PO for confirming delivery and link confirmation
Control PDUs such as LL-PDU and RS-PDU are output to rate control section 102.

Next, a PDU transmission process by the rate control of the rate control unit 102 will be described with reference to a flowchart shown in FIG.

However, at the time of line setting, the rate control unit 102 performs an initial setting of the rate control table 109 described below according to the radio frame length and the unit time notified from the parameter management unit 103.

That is, the transmission permission PDU length 111 is calculated by (radio transmission rate × unit time) / 1 radio frame period.

The number 113 of transmission-permitted PDUs is calculated as follows: unit time / 1
It is defined by the radio frame period. For example, if the radio frame period is 10 ms and the unit time is 100 ms, 10P
DU.

At this time, since no PDU has been transmitted, the transmittable PDU length 112 is set to the transmission permitted PDU length 111, and the transmittable PDU number 114 is set to the transmission permitted PDU number 1
Set to 13.

Further, if the unit time is shortened, transmission can be performed accurately in accordance with the transmission speed. However, since the processing described later in the unit time occurs frequently, the processing amount increases. On the other hand, when the length is increased, the processing amount decreases, but the error in the transmission rate increases.

After such initialization, the rate control unit 10
2 is activated by a timer process at the time of PDU transmission and at a unit time interval.

In step ST201 of FIG. 2, rate control section 102 transmits the PDU to be transmitted when transmitting the PDU.
Is the transmittable P set in the rate control table 109.
It is determined whether or not the DU length 112 and the number of transmittable PDUs 114 have not been exceeded.

If it is determined that the transmission PDU length is not exceeded, in step ST202, the transmission PDU length is subtracted from the transmission available PDU length 112. In step ST203, the required frame number is subtracted from the transmission available PDU number 114, and then in step ST204. , And outputs the transmission PDU to the transmission processing unit 106.

On the other hand, as a result of the determination in step ST201, when the transmission PDU length 112 or the transmission possible PDU number 114 is exceeded, in step ST205, the transmission P
Queue the DU.

The transmission of the queued PDU is performed in a timer process started in the next unit time. This processing will be described with reference to the flowchart shown in FIG.

In step ST301, the rate control unit 1
In step 02, when an interrupt notification is transmitted from the timer processing unit 105 for each unit time, it is determined whether or not there is a transmission packet in the transmission queue 119.

As a result of this determination, if there is no, the process is terminated, and if there is, in step ST302, the length and number of transmission packets are set to the transmittable PDU length 112 and transmittable PDU number 114 set in the rate control table 109. It is determined whether it does not exceed.

If it is determined that the transmission packet length is not exceeded, in step ST303, the transmission packet length is subtracted from the transmittable PDU length 112, and in step ST304,
After subtracting (transmission packet length / 1 radio frame length) from the number of transmittable PDUs 114, the transmission packet is output from the transmission queue 119 to the transmission processing unit 106 in step ST305.

The PD when such rate control is performed
The transmission timing of U is shown in FIG.

In FIG. 4, P
A timing example when a transmission of a DU is requested is shown, and a timing example when a PDU is transmitted after rate control is performed on the left side of the time axis t.

In this example, the number of transmittable PDUs 114 = 2
In the unit time t1, the first and second PDUs 40
1,402 was sent because it was within the transmittable range,
Since the third and fourth PDUs 403 and 404 have exceeded the transmittable range, they are queued and transmitted at the next unit time t2.

That is, P which can be transmitted according to the transmission rate
If it is a DU, it is immediately transmitted to the base station apparatus 501, and a PDU exceeding the transmission rate is queued and transmitted in the next unit time, thereby shortening the propagation delay and allowing the base station apparatus 501 to transmit data in bursts. The reception is lost.

As described above, according to the packet communication device 100 of the present embodiment, the SSCOP protocol processing unit 10
In step 1, the packet data received from the packet terminal 505 is subjected to SSCOP protocol processing to generate a PDU. For each unit time corresponding to the holding time when data becomes full from 0, the PD from the SSCOP protocol processing unit 101
U determines whether or not it can transmit to the buffer, transmits a PDU determined to be transmittable, and transmits a PDU determined to be untransmittable within the next unit time. The base station device 50 can be shortened.
1 can be prevented from receiving data in bursts.

Since the PDU or the packet can be transmitted in consideration of the radio frame length, it is difficult to transmit the packet in consideration of the radio frame length as in the related art. By setting a larger value, the base station device 501 does not need to prepare a large-capacity packet buffer. That is, the buffer of the base station device 501 can be made smaller than before.

An ATM communication LSI unit 10 which decomposes a transmission packet into ATM cells, transmits the ATM cells to the base station 501, and assembles the ATM cells received from the base station 501 into packet data.
7, the base station device 501 can perform high-speed transmission using ATM cells.

[0071]

As described above, according to the present invention,
The reception buffer of the base station apparatus can be reduced, and the transmittable packet can be transmitted with less delay.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a packet communication device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an operation of a PDU transmission process by rate control of the packet communication device according to the embodiment.

FIG. 3 is a flowchart for explaining the operation of a timer interrupt notification receiving process by the packet communication device according to the embodiment.

FIG. 4 is a PD of the packet communication device according to the above embodiment.
U or packet transmission request timing and transmission timing diagram

FIG. 5 is a block diagram showing a configuration of a mobile communication system using a conventional packet communication device.

FIG. 6 is a block diagram showing a configuration of a conventional packet communication device.

[Description of Signs] 100 Packet Communication Device 101 SSCOP Protocol Processing Unit 102 Rate Control Unit 107 ATM Communication LSI Unit

Claims (5)

[Claims] 1. A unit for determining whether packet data from a processing unit can be transmitted to a buffer provided in a base station apparatus with a capacity corresponding to a wireless transmission capacity to the buffer for each unit time. A packet communication apparatus comprising: a rate control unit configured to transmit the received packet data and transmit the packet data determined not to be transmitted within a next unit time. 2. An ATM communication processing means for decomposing transmission packet data into ATM cells, transmitting the ATM cells to a base station apparatus, and assembling the ATM cells received from the base station apparatus into packet data. Item 2. The packet communication device according to item 1. 3. A base station controller comprising the packet communication device according to claim 1. 4. A mobile communication system comprising the base station control device according to claim 3. 5. It is determined whether or not packet data subjected to retransmission protocol processing can be transmitted to a buffer provided in a base station apparatus with a capacity corresponding to a wireless transmission capacity to the buffer at each unit time, and the packet data can be transmitted. The packet communication method according to claim 4, wherein the determined packet data is transmitted, and the packet data determined to be untransmittable is transmitted within a next unit time.