JP3313563B2 - Data transmission control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission control system for transmitting and receiving data at an asymmetric data transmission rate between a portable information terminal and an information providing station for providing information to the portable information terminal. About the method.

[0002]

2. Description of the Related Art In general, a data transmission system for mutually transmitting data between two stations generally has a first station 101 and a second station which mutually transmit and receive data, as shown in FIG. And a first transmission system 1 for transmitting data from the first station 101 to the second station 102
03 and a second transmission system 104 for transmitting data from the second station 102 to the first station 101.

When data is exchanged in such a data transmission system, conventionally, for example, HDLC (High)
By using a data link protocol such as level data link control, the reliability of data is assured by sending a data delivery confirmation frame or a retransmission request frame. At this time, the first transmission system 103 and the second transmission system 104 form a data link loop.

Here, a system as shown in FIG. 13 is assumed. That is, the first station 111 and the second station 112, which mutually transmit and receive data, and the first station 11
A first transmission system 113 and a second transmission system 114 for transmitting data from the first station to the second station 112;
And a third transmission system 115 for transmitting data from the first station 112 to the first station 111.

[0005] In such a transmission system, a data link is formed by a first loop formed by a first transmission system 113 and a third transmission system 115 and a second loop formed by a second transmission system 114 and a third transmission system 115. There is a loop of. That is, the data link is multiplexed on the third transmission system.

At this time, as a method of multiplexing the data link, a method in which the first loop and the second loop alternately use the third transmission system 115 or a method in which the data is used in the order in which the data is generated is generally used. It is a target.

[0007]

However, when the third transmission system 115 is shared by two data link loops, if the third transmission system 115 is used in the order of data generation, for example,
The first data link loop is the first transmission system 113
When the response data for the user data transmitted by the second station 11 is returned using the third transmission system,
2 has already stored a large amount of user data to be sent to the second data link loop,
After waiting for the transmission of the user data, response data to the user data transmitted by the first transmission system is returned.

During this time, retransmission due to timeout occurs because response data to the data transmitted by the first transmission system cannot be returned, and the first transmission system 113 and the third transmission system 115 There is a problem that the efficiency of data transmission by one data link loop is deteriorated.

In particular, when the first transmission system 113 realizes high-speed data transmission, the restrictions on response transmission become more severe. Therefore, the present invention has been made in view of the above problems, and when performing data transmission through a plurality of transmission paths between a first station and a second station,
Even when a plurality of data links are overlapped on one of the plurality of transmission paths, response data to received data or user data can be efficiently transmitted according to the characteristics of each data link. It is an object to provide a data transmission control method.

[0010]

According to the data transmission control method of the present invention, there are provided two downlink transmission paths having different characteristics from a first station to a second station, and the second station to the first station. In a data transmission control method for performing data transmission between the first station and the second station via one uplink transmission path to the second station, the second station includes: When transmitting the response data to the data packet transmitted through each of the user data and the user data generated in the second station through the uplink transmission path, one of the two downlink transmission paths is determined in advance. By transmitting the response data to the data packet transmitted via the downstream transmission path in preference to the response data and the user data to the data packet transmitted via the other downstream transmission path, the first station 1 When the data transmission via a plurality of transmission paths between the second station 2 (3 in this case), a plurality to one of the plurality of transmission paths (up transmission line) (in this case 2
Data links are duplicated,
It is possible to efficiently transmit response data or user data to received data according to the characteristics of each data link.

The data transmission control method according to the present invention further comprises two downlink transmission paths having different characteristics from the first station to the second station, and one downlink transmission path from the second station to the first station. In a data transmission control method for mutually performing data transmission between the first station and the second station via an uplink transmission line, the second station may communicate via each of the two downlink transmission lines. When transmitting the response data to the transmitted data packet and the user data generated in the second station via the uplink transmission path, one of the two downlink transmission paths is determined in advance. The packetized response data to the data packet transmitted through the other transmission line is transmitted in preference to the response data to the data packet transmitted through the other downstream transmission path and the packetized user data. By the first station 1 and the second
When data transmission is performed through a plurality of transmission paths (three in this case) with the station 2 of one of the plurality of stations 2, one (uplink transmission path) of the plurality of transmission paths (two in this case) Even when the data links are overlapped, it is possible to efficiently transmit response data to user data or user data according to the characteristics of each data link.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the configuration of a data transmission system using the data transmission control method according to the present embodiment. In FIG. 1, the direction from the first station 1 to the second station 2 is The direction from the second station 2 to the first station 1
The first station 1 and the second station 2 are a high-speed downlink transmission system 3 and a low-speed downlink transmission system 4 from the first station 1 to the second station 2, and an uplink from the second station 2 to the first station 1. They are connected so that they can communicate via the low-speed transmission system 5.

The downstream high-speed transmission system 3 is mainly used for transmitting a relatively large amount of data generated in bursts, and the downstream low-speed transmission system 4 is mainly used for transmitting a relatively small amount of data generated continuously. (For example, a voice signal) and a response to data transmitted by the uplink low-speed transmission system 5 described later. The uplink low-speed transmission system 5 transmits a response to data transmitted by the downlink high-speed transmission system 3 and a downlink low-speed transmission. It is used in transmitting a response to data transmitted by the system 4 and a relatively small amount of continuously generated data.

That is, in the data transmission system shown in FIG.
And a first loop of the uplink low-speed transmission system 5 and a second loop of the downlink low-speed transmission system 4 and the uplink low-speed transmission system 5.
This means that one data link is overlapped.

First, a first embodiment will be described.
FIG. 2 schematically shows a configuration example of the second station 2 according to the first embodiment.

In FIG. 2, a data packet transmitted by the downlink high-speed transmission system 3 is received by a first receiving unit 11 and is input to a first data packet checking unit 12, where an error is checked. If no error is detected, an acknowledgment is sent. If an error is detected, the first response data is passed to the data packetizing unit 19 as a check result in order to send a retransmission request as a response.

The data packet transmitted by the downstream low-speed transmission system 4 is received by the second receiving unit 14,
The error is input to the second data packet inspection unit 15 and the error is inspected. If no error is detected, an acknowledgment is sent. If an error is detected, the second response data is passed to the data packetizing unit 19 as a check result in order to send a retransmission request as a response.

The data packetizing section 19 transmits the two responses (the first response data and the second response data) and the second station 2
The user data generated in step (1) is received, stored, selected, packetized, and passed to the transmission unit 18. At this time, the first response data from the first data packet inspection unit 12 is preferentially packetized and passed to the transmission unit 18.

The transmitting unit 18 transmits the packet passed from the data packetizing unit 19 to the first station 1 using the uplink low-speed transmission system 5. FIG. 3 shows the data packetizer 19.
This is an example of the configuration.

In FIG. 3, the data packetizing section 19
Are the first response data from the first data packet inspection unit 12 and the second response data from the second data packet inspection unit 15
Response data and user data, respectively,
The data is temporarily stored in the first buffer 51, the second buffer 52, and the third buffer 53.

The selecting section 54 includes a first buffer 51, a second
Of the buffer 52 and the third buffer 53 are monitored, and the first response data stored in the first buffer 51 is selected in preference to the data stored in the other buffers 52 and 53. Is performed.

The packet generation unit 55 generates a packet of a predetermined format based on the data selected by the selection unit 54, and transmits the generated packet to the transmission unit 18.

FIG. 4 shows a specific example of the data format of a packet transmitted by the downlink high-speed transmission system 3, which is roughly divided into a header section and an information section. The header section includes control information such as a destination address and parity bits for error detection in the header section. The information section is divided into a plurality of segments, and each segment is composed of user data, a sequence number of the user data, and parity bits for error detection.

FIG. 5 shows a specific example of the data format of a packet transmitted by the downstream low-speed transmission system 4, which is composed of control information, user data, and parity bits for detecting packet errors.

FIG. 6 shows a specific example of the data format of a packet transmitted by the uplink low-speed transmission system 5, which is composed of a downlink channel identifier, control information, user data or response data, and parity bits for error detection. Have been.

When transmitting response data to data transmitted by the downlink high-speed transmission system 3 or the downlink low-speed transmission system 4, the downlink channel identifier is response data to data transmitted by which downlink transmission system. It is for identifying.

In the control information, in addition to the control information necessary for data transmission such as a transmission destination address, a portion of the first response data related to the header portion or the second response data is an acknowledgment. Or a request for retransmission depending on whether the request is a retransmission request or not.

Further, the packet transmitted by the upstream low-speed transmission system 4 includes the information part of the user data generated in the second station 2 or the first response data to the data transmitted by the downstream high-speed transmission system 3. And a parity bit for error detection thereof.

FIG. 7 shows a specific example of the format of a portion related to the information section of the first response data output from the first data packet inspection section 12 of FIG. It is composed of response data corresponding to each segment constituting the information part of the transmitted packet having the format as shown in FIG.

That is, the first data packet inspection unit 1
In step 2, the packet data as shown in FIG. 4 is checked for each segment, and as a result of the check, the sequence number of the user data in each segment, an acknowledgment (A) for the user data, a retransmission request (N)
Are arranged by the number of the segments to output a portion relating to the information portion of the first response data having the configuration as shown in FIG. 7, and an error in the header portion of the packet data as shown in FIG. As an inspection result, an acknowledgment of the entire packet data or a retransmission request is output.

The packet data having the format as shown in FIG.
Is transmitted to In the second station 2, first, the first receiving unit 1
1 and input to the first data packet checker 12, where errors in the header and information are checked. An error in the information section is checked for each segment. As a result of checking for errors in the header portion, if no error is detected, an acknowledgment of the entire packet is issued. If no error is detected, a retransmission request is sent using the packet control information shown in FIG. It is passed to the data packetizing means 19 as a portion related to the information part of the first response data for transmission. At the same time, as a result of checking for errors in each segment of the information section, if no error is detected, an acknowledgment is sent, and if an error is detected, a retransmission request is sent as a response. The portion relating to the information portion of the first response data in a special format is passed to the data packetizing means 19.

On the other hand, the packet data having the format as shown in FIG.
Is transmitted to the station 2. In the second station 2, first, the data is received by the second receiving unit 14, and the second data packet searching unit 1
5 where the error is checked. If no error is detected, an acknowledgment is sent. If an error is detected, a check result is sent to the data packetizing means 19 as second response data to send a retransmission request as a response.

Next, a data transmission control method in the data transmission system configured as described above will be described with reference to a flowchart shown in FIG. FIG. 8 mainly shows the processing operation of the data packetizing unit 19.

The selection unit 54 includes a first buffer 51, a second
First, when it is detected that data (first response data) is present in the first buffer 51, the data storage amounts of the buffer 52 and the third buffer 53 are monitored (Step S).
1) Extract data from the first buffer 51 and pass it to the packet generator 55.

The packet generation unit 55 performs a downlink for identifying the response data to the data transmitted by the downstream high-speed transmission system 3 in the packet format transmitted by the upstream low-speed transmission system 5 as shown in FIG. A channel identifier is set (step S2).

Then, of the response data extracted from the first buffer, a portion related to the header portion of the packet transmitted by the downstream high-speed transmission system 3 as shown in FIG. The control information of the packet having the format as shown in FIG. 6 is set by reflecting the control information of the packet as shown in FIG. 4 (step S3).

Further, of the response data, a portion relating to the information section is set in response data of a packet having a format as shown in FIG. 6 (step S4). Finally, a parity is added (step S5), and sent to the transmission unit 18.

On the other hand, in step S1, the selection unit 54
When data is not stored in the first buffer 51, the process proceeds to step S7, and it is checked whether data is stored in the second buffer 52.

When there is data (second response data) in the second buffer 52, the data is taken out from the second buffer 52 and passed to the packet generator 55. The packet generation unit 55 sets a downlink channel identifier for identifying response data to data transmitted by the downlink low-speed transmission system 4 in the downlink channel identifier part of FIG. 6 (step S8). Then, the received second response data is an acknowledgment or the control information for reflecting the response in response to the retransmission request is transmitted to the control information of the packet transmitted by the uplink low-speed transmission system 5 as shown in FIG. (Step S9). Further, the selection unit 54 checks whether user data is stored in the third buffer 53 (Step S1).
0).

If there is user data in the third buffer 53, it is taken out and sent to the packet generator 55. The packet generator 55 sets the received user data in the user data of FIG. 6 (step S11). ),
Thereafter, the process proceeds to step S5. If there is no user data in the third buffer 53, the user data portion is left empty (step S12), and the process proceeds to step S5.

In step S5, as shown in FIG.
Parity is added and sent to the transmission unit 18 (step S
6). In step S7, if no data is stored in the second buffer 52, the selection unit 54 proceeds to step S1.
Return to That is, the second station 2 has the first buffer 5
1. Wait for packet transmission until data is stored in any of the buffers 52.

In step S6, the transmitting unit 18 uses the uplink low-speed transmission system 5 to
The packet as shown in FIG.
To be transmitted.

As described above, according to the first embodiment, in the data packetizing section 19 of the second station 2, the first response data for the packet transmitted by the downlink high-speed transmission system 3 is Downstream low-speed transmission system 4
The first and second stations 1 and 2 are packetized with priority over the second response data and user data for the packet transmitted by the first station 1 and transmitted to the first station 1 by the uplink low-speed transmission system 5. When data transmission is performed via a plurality of transmission paths (three in this case) between one of the plurality of transmission paths (in this case, two low-speed transmission systems 5), Even if the data links are overlapped, it is possible to efficiently transmit response data to user data or user data according to the characteristics of each data link.

Next, a second embodiment will be described.
FIG. 9 schematically illustrates a configuration example of the second station 2 according to the second embodiment.

In FIG. 9, the packet transmitted by the downlink high-speed transmission system 3 as shown in FIG. 4 is received by the first receiving unit 21 and input to the first data packet inspecting unit 22, and its header is The part and the information part are checked for errors. The information section is checked for errors for each segment. If an error is not detected, an acknowledgment is sent. If an error is detected, a retransmission request is sent as a response. The inspection result (first response data) is passed to the first data packetizing means 23.

The first data packetizer 23 packetizes the data into a format as shown in FIG. this,
Here, it is referred to as a first packet. That is, the portion related to the information section of the first response data as shown in FIG. 7 is set in the response data of FIG. 6 to identify the response data to the packet transmitted by the downlink high-speed transmission system 3. A downlink channel identifier is set, and the control information of FIG. 6 is made to correspond to the control information of the packet transmitted by the downlink high-speed transmission system 3 as shown in FIG. Set according to the part related to. The first packet is passed to the data packet storage / selection unit 27.

The packet transmitted by the downstream low-speed transmission system 4 is received by the second receiving unit 24 and is input to the second data packet checking unit 25, where the error is checked. If no error is detected, an acknowledgment is sent. If an error is detected, a check result is sent to the second data packetizing unit 26 as second response data to send a retransmission request as a response.

The second data packetizing section 26 packetizes the data together with the second response data and the user data generated in the second station 2 into a format as shown in FIG. This is referred to herein as a second packet. That is, the second
6 is set in the user data section of FIG. 6, and a downlink channel identifier for identifying response data to data transmitted by the downlink low-speed transmission system 4 is set. Depending on whether the response data is an acknowledgment or a retransmission request, control information that reflects this is set. The second packet is passed to the data packet storage / selection unit 27.

The data packet storage / selection unit 27 comprises a first data packetizing unit 23 and a second data packetizing unit 2
6, the first packet and the second packet are respectively received, temporarily stored, selected, and passed to the transmission unit 28. At this time, the first packet passed from the first data packetizing unit 23 is passed to the transmitting unit 28 in preference to the second packet passed from the second data packetizing unit 26.

The transmission unit 28 transmits the packet passed from the data packet storage / selection unit 27 to the first station 1 using the uplink low-speed transmission system 5. FIG. 10 shows a configuration example of the data packet storage / selection unit 27.

In FIG. 10, the data packet storage / selection unit 27 receives the first data packet from the first data packetizing unit 23.
, And the second packet from the second data packetizing unit 26, and respectively receive the first buffer 6
First, the data is temporarily stored in the second buffer 6.

The selecting section 63 includes a first buffer 61 and a second buffer 61.
The first packet stored in the first buffer 61 is selected in preference to the second packet stored in the second buffer 62, and the transmission unit 18 To be passed to.

Next, a data transmission control method in the data transmission system according to the second embodiment will be described with reference to the flowchart shown in FIG. FIG. 11 mainly shows the processing operation of the data packet accumulation / selection unit 27.

The selector 63 includes a first buffer 61, a second buffer 61,
The amount of data stored in the buffer 62 is monitored.
When it detects that there is data in the buffer 61 (step S20), it extracts the data (first packet) from the first buffer 61 (step S21) and passes it to the transmission unit 18 (step S22).

On the other hand, in step S20, the selecting section 6
When the data is not stored in the first buffer 61, the process proceeds to step S23, and checks whether the data is stored in the second buffer 62.

When there is data in the second buffer 62, the data (the second packet) from the second buffer 62
Is taken out (step S24) and passed to the transmission unit 28 (step S22).

In step S23, if there is no second packet in the second buffer 53, the process returns to step S20. That is, the second station 2 is in a packet transmission waiting state until data is accumulated in either the first buffer 61 or the second buffer 62.

In step S22, the transmitting unit 28
Data packet accumulation /
The packet transmitted from the selection unit 27 is transmitted to the first station 1. As described above, according to the second embodiment, the data packet storage / selection unit 27 of the second station 2 packetizes the response to the packet transmitted by the downlink high-speed transmission system 3. A packet is selected with priority over the response to the data transmitted by the downstream low-speed transmission system 4 and the second packet generated based on the user data, and the upstream low-speed transmission system 5
When transmitting data to the first station 1 via a plurality of transmission paths (three in this case) between the first station 1 and the second station 2, the plurality of transmissions One out of the road
Even if a plurality of (in this case, two) data links are overlapped in one (in this case, the uplink low-speed transmission system 5), response data to user data or user data is received according to the characteristics of each data link. It is possible to transmit efficiently.

In the data transmission system described above, it is assumed that voice communication is performed using, for example, the low-speed downstream transmission system 4 and the low-speed upstream transmission system 5. At this time, it is assumed that a large amount of data such as an image is downloaded by the downstream high-speed transmission system 3. At this time, in the present invention, a response (reception confirmation and retransmission request) to the data transmitted by the downstream high-speed transmission system 3 is transmitted using the upstream low-speed transmission system prior to the voice call information.

Conventionally, a response (acknowledgment and retransmission request) to the data downloaded by the downlink high-speed transmission system 3 cannot be transmitted or the transmission is delayed, so that a timeout occurs and retransmission occurs. The possibility of getting lost has increased. That is, when multiplexing two data links in a conventional manner,
Retransmission due to timeout was likely to occur.

According to the present invention, the transmission of data downloaded by the downstream high-speed transmission system 3, which has a severe delay limit, is preferentially transmitted, so that retransmission is less likely to occur due to a timeout. Efficiency is improved.

[0062]

As described above, according to the present invention,
When performing data transmission via a plurality of transmission paths between the first station and the second station, even when a plurality of data links are overlapped on one of the plurality of transmission paths. In addition, it is possible to provide a data transmission control method capable of efficiently transmitting response data to user data or user data according to the characteristics of each data link.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a data transmission system according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing a configuration of a second station of the data transmission system according to the first embodiment.

FIG. 3 is a block diagram schematically showing a configuration of a data packetizing unit.

FIG. 4 is a diagram showing a specific example of a format of packet data transmitted in the downlink high-speed transmission system.

FIG. 5 is a diagram showing a specific example of a format of packet data transmitted in the downlink low-speed transmission system.

FIG. 6 is a diagram showing a specific example of a format of packet data transmitted in the uplink low-speed transmission system.

FIG. 7 is a diagram showing a specific example of a format of response data to packet data transmitted in the downlink high-speed transmission system.

FIG. 8 is a flowchart illustrating a processing operation of a data packetizing unit.

FIG. 9 is a block diagram schematically showing a configuration of a second station of the data transmission system according to the second embodiment.

FIG. 10 is a block diagram schematically showing a configuration of a data packet storage / selection unit.

FIG. 11 is a flowchart illustrating a processing operation of a data packet storage / selection unit.

FIG. 12 is a diagram showing a configuration of a data transmission system using a conventional data transmission control method.

FIG. 13 is a diagram showing another configuration of a data transmission system using a conventional data transmission control method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st station, 2 ... 2nd station, 3 ... High-speed downlink transmission system, 4 ... Low-speed downlink transmission system, 5 ... Low-speed uplink transmission system.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eiji Kamagata 1st Toshiba-cho, Komukai-shi, Saitama-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Kiyoshi Toshimitsu Kiyoshi Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa No. 1 Toshiba R & D Center Co., Ltd. (72) Inventor Noriyasu Kato No. 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center Co., Ltd. (56) References JP-A-6-6381 (JP A JP-A-9-186740 (JP, A) JP-A-7-143181 (JP, A) JP-A-62-189823 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 H04L 1/16 H04L 29/06

Claims (2)

(57) [Claims] 1. The second station comprises two downlink transmission paths having different characteristics from a first station to a second station, and one uplink transmission path from the second station to the first station. Station 1 and the second
In the data transmission control method of mutually performing data transmission between the second station, the second station, response data to a data packet transmitted via each of the two downlink transmission paths and the second station When transmitting the generated user data through the uplink transmission path, the response data to the data packet transmitted through one predetermined downlink transmission path of the two downlink transmission paths is transmitted to the other downlink transmission path. A data transmission control method characterized in that transmission is performed prior to response data and user data for a data packet transmitted via a channel. 2. The method according to claim 1, further comprising: two downlink transmission paths having different characteristics from the first station to the second station; and one uplink transmission path from the second station to the first station. Station 1 and the second
In the data transmission control method of mutually performing data transmission between the second station, the second station, response data to a data packet transmitted via each of the two downlink transmission paths and the second station When transmitting the generated user data through the uplink transmission path, packetized response data to a data packet transmitted through a predetermined one of the two downlink transmission paths is transmitted. A data transmission control method characterized in that response data to a data packet transmitted via the other downlink transmission path and the user data are transmitted in preference to packetized user data.