JPH10242948A - Data frame resending control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data frame resending control device capable of reducing the load of transfer processing in the case of executing data frame resending processing. SOLUTION: A temporary buffer 10 temporarily stores a data frame to be sent to a receiving station 3. A transmission buffer 20 stores the data frame transferred from the buffer 10. A resending means 30 receives a data frame resending request from the receiving station 3 and resends the requested data frame. When a space area for plural data frames is generated due to the resending of the data frame from the buffer 20, a transfer control means 40 controls data transfer so as to transfer each data frame from the buffer 10 to the buffer 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data frame retransmission control device, and more particularly to a data frame retransmission control device for retransmitting a data frame of a transmitting station based on a data frame retransmission request of a receiving station.

[0002]

2. Description of the Related Art Mobile communication is susceptible to noise and interference, and the error rate may be significantly degraded by fading or the like. Therefore, an error control technique is indispensable. One of such error controls is a retransmission system. In this method, a response signal for transmission is provided, and if a response signal cannot be received after a certain period of time after transmission, the same information is transmitted again.

In error control of a retransmission system, SR-ARQ
(Selective automatic retransmission control: SelectiveRepeat-Automatic Re
peat Request) system is applied to PHS and the like. When an error is detected on the receiving side, the SR-ARQ system holds the correct data received thereafter in a buffer memory, controls the sequence number, and requests retransmission of only the error data.

FIG. 7 is a conceptual diagram showing the processing of a conventional SR-ARQ system. DTE (Date Terminal Eq
uipment) 100 outputs a data frame. The transmission buffer 200 stores a data frame with a continuous number (transmission modulo) added thereto. If it is modulo N, the number of storage areas is N-1. Thereafter, the data frames to which the transmission modulo has been added are sequentially transmitted.

[0005] The receiving buffer 300 receives these data frames. The receiving DTE 400 assembles the transmitted data frame and performs information processing. Here, the receiving side sets the modulo number of the next data frame to be received as the receiving modulo based on the transmission modulo of the data frames transmitted in sequence, and transmits this as a response signal to the transmitting side.

[0006] Thus, the transmission side can determine whether or not data has been normally received based on the reception modulo. For example, in the figure, the reception of the reception data frame 301 of the reception modulo "2" by the transmission side is proof that the reception side has received the transmission data frame 201 of the transmission modulo "1".

Therefore, when the receiving side detects erroneous data, data retransmission processing is performed. By performing such operations in both directions, reliable data transmission is guaranteed.

[0008]

However, in the conventional system as described above, when retransmission processing of error data is performed, the storage area of the transmission buffer for a plurality of data frames is released at a time.

Therefore, if the data frame is to be temporarily transferred (written) as much as the buffer is released, a load is imposed on the transfer processing, and other processing that should be performed within the data frame reception interval cannot be performed in time. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to provide a data frame retransmission control device which reduces a load of a transfer process when performing a data frame retransmission process.

[0011]

According to the present invention, there is provided a data frame retransmission control apparatus for retransmitting a data frame of a transmitting station based on a data frame retransmission request of the receiving station. A temporary buffer for temporarily storing data frames to be
A transmission buffer that stores the data frame transferred from the temporary buffer, a retransmission unit that receives a retransmission request for the data frame from the receiving station, and retransmits the requested data frame; and Transfer control means for controlling transfer of only one data frame from the temporary buffer to the transmission buffer when a data frame is retransmitted and a free area for a plurality of data frames is created. A data frame retransmission control device is provided.

Here, the temporary buffer temporarily stores a data frame to be transmitted to the receiving station. The transmission buffer stores the data frame transferred from the temporary buffer. The retransmitting means receives the data frame retransmission request from the receiving station and retransmits the requested data frame. The transfer control means controls to transfer only one data frame from the temporary buffer to the transmission buffer when a data frame is retransmitted from the transmission buffer and an empty area for a plurality of data frames is created.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram of a data frame retransmission control device according to the present invention. The data frame retransmission control device 1 controls retransmission of a data frame from the transmitting station 2 to the receiving station 3.

[0014] The temporary buffer 10 temporarily stores a data frame to be transmitted to the receiving station 3. The transmission buffer 20 stores the data frame transferred from the temporary buffer 10. The retransmitting means 30 receives the data frame retransmission request from the receiving station 3 and retransmits the requested data frame. When a data frame is retransmitted from the transmission buffer 20 to create a free space for a plurality of data frames, the transfer control means 40 controls to transfer only one data frame from the temporary buffer 10 to the transmission buffer 20.

Next, the operation will be described. FIG. 2 is a flowchart showing a schematic operation procedure of the data frame retransmission control device 1. [S1] The temporary buffer 10 receives a data frame to be transmitted to the receiving station 3 from the transmitting station 2, and temporarily stores the data frame. [S2] The transmission buffer 20 is the temporary buffer 10
The data frame transferred from is stored. Then, the data frame is transmitted to the receiving station 3. [S3] When an error is detected in the receiving station 3, the receiving station 3 requests retransmission of the data frame. [S4] The retransmitting means 30 receives the data frame retransmission request from the receiving station 3, and retransmits the requested data frame. [S5] When the data frame is retransmitted from the transmission buffer 20 in the operation of step S4 and a free area for a plurality of data frames is created, the transfer control unit 40 transmits the corresponding plurality of data frames from the temporary buffer 10 to the transmission buffer 20. Control is performed such that data frames are transferred one by one without being temporarily transferred.

As described above, the data frame retransmission control device 1 according to the present invention, when an empty area corresponding to a plurality of data frames is generated in the transmission buffer 20 for storing data frames, temporarily stores the data in the temporary buffer 1 for each data frame.
The configuration is such that the data is transferred from 0 to the transmission buffer 20. This makes it possible to reduce the load of the transfer processing.

Next, the retransmission control procedure will be described in detail. In the following description, PI which is a PHS transmission standard is used.
A case where the present invention is applied to an SR-ARQ system defined by AFS (PHS Internet Access Forum Standard) will be described.

FIG. 3 is a sequence diagram showing the flow of the retransmission control procedure. The transmission buffer 20 stores data frames 1 and 2
.. (The numbers are modulo numbers) are sequentially received by the receiving station 3.
Is transmitted to the receiving buffer 3a located inside. Then, the reception buffer 3a returns a response signal Rn indicating the next modulo number n to be transmitted to the transmission buffer 20 every time reception is performed.

For example, when the receiving buffer 3a receives the data frame 1, the modulo number of the next data frame to be received is 2, so that R2 is transmitted to the transmission buffer 20 as a response signal.

Here, a case will be described in which the data frame 3 is lost during data frame transmission and does not reach the reception buffer 3a in order. [S10] Receive data frame 2 and return R3. [S11] The data frame 3 does not reach the reception buffer 3a (indicated by a dotted arrow), and therefore, the reception buffer 3a returns R3. [S12] The data frames 4 and 5 transmitted next are received without receiving the data frame 3. Therefore, R3 is returned correspondingly. [S13] It is assumed that the data frame 6 and the data frame 3 have been received at this time (indicated in the figure). Then, since data frames 1 to 6 have already been received, reception buffer 3a returns R7. Thereafter, the retransmission control is performed in the same manner.

Next, the release of the transmission buffer 20 will be described. The release means that the next data can be written since it has been confirmed that the data has been received by the other party. As shown in the figure, since the transmission buffer 20 receives R2 at point A, it releases the area 1 in which the data frame 1 is stored. R3 at point B
Therefore, the area 2 in which the data frame 2 is stored is released next. Further, at point C, since R7 is received, a plurality of regions of 3 to 6 can be opened.

Next, the CPU processing when the area of the transmission buffer 20 is released will be described. The CPU here may be in charge of the entire system of the data frame retransmission control device 1 or may be used for the transfer control means 40.

FIG. 4 is a diagram showing CPU processing when writing a plurality of data frames at once. The data frame reception interval in the figure indicates one cycle of data frame communication performed between the transmitting station 2 and the receiving station 3. The three CPU processes performed within the data frame reception interval are data frame acquisition, transmission buffer release / transfer 20a, and data frame transmission. If the transmission buffer has an empty area for a plurality of data frames and the plurality of data frames are transferred from the temporary buffer 10 to the transmission buffer 20 at one time, the processing time of the transmission buffer release / transfer 20a becomes longer, and the CPU performs the processing within the data frame reception interval. Processing load increases.

FIG. 5 is a diagram showing the CPU processing when writing one data frame. When there is an empty area in the transmission buffer 20 for a plurality of data frames, and only one data frame is transferred from the temporary buffer 10 to the transmission buffer 20 in this area as in the present invention, the processing time of the transmission buffer release / transfer 20a is compared with FIG. The load on the CPU processing performed within the data frame reception interval is reduced.

Next, the data frame structure will be described. FIG. 6 shows a data frame structure. The data frame 10a is an identifier that gives a data frame type. FI is 4 bits. The FFI, which is the transmission frame number corresponding to the transmission modulo, and the FBI, which is the reception frame number corresponding to the reception modulo, are both 6 bits, and implement the SR-ARQ system with 63 modulos 1 to 63.

Also, the data length is 8 bits, the user data is 584 bits, and the FC for judging the correctness of the data frame.
S is 32 bits, and the data frame 10a is 64
0 bits.

On the other hand, in PIAFS, data frames are transmitted at intervals of 20 ms. Since there is a transmission buffer of 63 modulo, if a communication error occurs, an area for 63 modulos at a maximum, that is, 40320 (= 6
An area of (40 × 63) bits is released at a time. If such data frames are transferred at one time within 20 ms, variations occur in the CPU processing per cycle.
Therefore, the data frame to be written to the transmission buffer during 20 ms is set to only 640 bits per data frame.
This reduces the load on the CPU processing. Also,
Since the number of data frames transmitted in one cycle is only one data frame, there is no possibility that no data frame is transmitted, and communication is performed reliably.

In the above description, the present invention has been described as being applied to the SR-ARQ system defined by PIAFS. However, the present invention can be similarly applied to other retransmission systems.

[0029]

As described above, the data frame retransmission control device according to the present invention, when an empty area corresponding to a plurality of data frames is generated in the transmission buffer for storing data frames, from the temporary buffer for each data frame. It was configured to transfer to the transmission buffer. This makes it possible to reduce the load on the transfer process during one cycle of data frame communication.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a data frame retransmission control device according to the present invention.

FIG. 2 is a flowchart illustrating a schematic operation procedure of the data frame retransmission control device.

FIG. 3 is a sequence diagram showing a flow of a retransmission control procedure.

FIG. 4 is a diagram illustrating C when writing a plurality of data frames at once.
It is a figure showing PU processing.

FIG. 5 is a diagram showing CPU processing when writing one data frame.

FIG. 6 is a diagram showing a data frame structure.

FIG. 7 is a conceptual diagram showing processing of a conventional SR-ARQ system.

[Explanation of symbols]

1 ... data frame retransmission control device, 2 ... transmission station, 3
... Receiving station, 10 temporary buffer, 20 transmission buffer, 30 retransmission means, 40 transfer control means.

Claims (2)

[Claims] 1. A data frame retransmission control device for retransmitting a data frame of a transmitting station based on a data frame retransmission request of a receiving station, comprising: a temporary buffer for temporarily storing a data frame to be transmitted to the receiving station; A transmission buffer that stores the data frame transferred from the temporary buffer; a retransmission unit that receives a retransmission request for the data frame from the receiving station and retransmits the requested data frame; And a transfer control means for controlling transfer of only one data frame from the temporary buffer to the transmission buffer when an empty area for a plurality of data frames is created by retransmitting the frame. Data frame retransmission control device. 2. The method according to claim 1, wherein the transfer control unit is configured to perform, during one cycle of data frame communication between the transmitting station and the receiving station,
2. The data frame retransmission control device according to claim 1, wherein control is performed such that only one data frame is transferred from the temporary buffer to the transmission buffer.