JP2004032283A - Transmitting device, receiving device, transmitting program, receiving agent, and transmitting/receiving program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiving device for monitoring the receiving state of a transmission packet and returning the receiving state to a transmitting device and to provide a transmitting device for forming the transmission packet, having a tolrance to errors matching a transmission path state and alleviating a processing load of the receiving device, a transmitting program, a receiving program and a transmitting/receiving program. <P>SOLUTION: The receiving device 6 includes a receiving buffer 7, an error deciding unit 8, a data packet transmitter 11, an error position specifying unit 9, an error correcting unit 10, and a transmission packet monitoring unit 12. The transmission packet monitoring unit 12 monitors the receiving buffer 7 and the error deciding unit 8, acquires a receiving interval of the transmission packets, the number of discarded packets, throughput and the like, and transmits an acquired result to the transmitting device 1. The device 1 includes a framing unit 2, a packet dividing unit 3, a packet generating unit 4, and a transmission parameter deciding unit 5. The deciding unit 5 decides the interleaving length and the payload, based on the information from the receiving device 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission device, a reception device, a transmission program, a reception program, and a transmission / reception program for transmitting and receiving a transmission packet encoded using a forward error correction method, and further monitoring a reception state of the transmission packet.
[0002]
[Prior art]
One method of correcting transmission errors is to add redundant bits to information bits and transmit them.If errors occur in some of the bits during transmission, use the redundant bits to detect erroneous bits on the receiving side. There is a forward error correction method (hereinafter, abbreviated as “FEC”) for correction. It is often used as an error control method in control signal transmission of a digital wireless communication system that requires error correction in real time.
[0003]
Further, as a method of specifying an error position when decoding information using a Reed-Solomon code as a redundant bit, for example, there are a Peterson method, a BM method, a Euclidean method, and the like. An error locator is calculated by the search, and an error position is specified.
[0004]
[Problems to be solved by the invention]
However, when this FEC is used by software processing in the third and higher layers of the OSI reference model, there is a problem in that the load of arithmetic processing for specifying an error position in received data is large.
[0005]
Further, the optimum configuration of the transmission packet (packet size and error tolerance) differs depending on the transmission path used. Therefore, for example, if a transmission packet used in a lower layer is a unit for specifying an error position, a problem arises in that the amount of calculation increases to specify the error position by software processing in the third and higher layers. there were.
[0006]
The present invention has been made in view of the above circumstances, and is a transmission / reception method for correcting a transmission packet in which an error has occurred during transmission by the FEC method in a third or higher layer of the OSI reference model. Receiving apparatus for monitoring the receiving status of the receiving device and returning the receiving status to the transmitting device, and a transmitting device and a transmitting program for creating a transmission packet having error resilience corresponding to the state of the transmission path and reducing the processing load of the receiving device , A receiving program, and a transmitting / receiving program.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a transmitting apparatus according to the first aspect of the present invention is a transmitting apparatus that encodes data by a forward error correction method to generate a transmission packet and transmits the transmission packet. Receiving at least the transmission interval of the transmission packet calculated from the reception state of the transmission packet at the transmission destination, the discard rate of the transmission packet, and the transmission parameter selected from the transmission throughput, And a packet generating means for generating the packet.
[0008]
The transmitting device according to the second aspect of the present invention is the transmitting device according to the first aspect, wherein the transmitting device is configured to transmit at least a transmission interval of the transmission packet from a transmission destination of the transmission packet, When a discard rate and a transmission throughput of the transmission parameter are received as a monitoring result, a parameter determining unit that selects one transmission parameter from a plurality of transmission parameters set in advance according to the monitoring result is provided.
[0009]
The transmitting device according to the third aspect of the present invention is the transmitting device according to the first or second aspect, wherein the transmission parameters include a payload size P of the transmission packet and an interleave length T. Frame forming means for forming a k.times.T data matrix composed of data of data length k and interleave length T as one frame, and a code length (k) for the data of data length k forming one frame. encoding means for adding an nk) error correction code to generate an n × T data matrix including the error correction code; and data obtained by adding an error correction code to the nxT data matrix. Interleave means for performing time interleave processing in accordance with the payload size P in a direction intersecting with the arrangement direction of the packets to generate a packet; It assigns a sequence number to the packet, characterized in that it comprises the sequence number, the interleaving length T, the payload size P, the direction of the interleaving, a header adding means for adding an error correction method as a header of the packet.
[0010]
Here, the unit of data handled in the present invention, such as the interleave length T and the payload size P, is a bit, a byte, or a symbol having an arbitrary number of bits or bytes (1 symbol = m bits or m bytes). I do.
[0011]
The receiving apparatus according to the fourth aspect of the present invention is a receiving apparatus that receives a transmission packet encoded using a forward error correction method, performs error correction, and then decodes the transmission packet. The reception device includes a reception buffer, monitors a reception state of the transmission packet stored in the reception buffer, and acquires at least a reception interval of the transmission packet, a discard rate of the transmission packet, and a transmission throughput as a monitoring result. And a packet monitoring means for returning the monitoring result to the transmission source of the transmission packet.
[0012]
A receiving device according to a fifth aspect of the present invention is the receiving device according to the fourth aspect, wherein, when the packet monitoring unit acquires the monitoring result, the receiving device responds to the monitoring result. There is provided a parameter determining means for selecting one transmission parameter from a plurality of transmission parameters set in advance and returning the transmission parameter to the transmission source of the transmission packet.
[0013]
A receiving device according to a sixth aspect of the present invention is the receiving device according to the fourth or fifth aspect, wherein the data stored in the receiving buffer is a data having a data length k and an interleave length T. An n × T data matrix including an error correction code is generated by adding an error correction code having a code length (nk) to the k × T data matrix composed of On the other hand, a transmission packet generated by performing time interleaving according to the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added, a sequence number assigned to each transmission packet, and the interleave length T , The transmission packet to which the payload size P, the interleaving direction, and the error correction method are added as a header, which are stored in the reception buffer. When there is a discarded transmission packet when reconstructing the one frame using the transmission packet to be transmitted, the sequence number of the discarded transmission packet is used as the error correction position of the data having the data length k. It is characterized by comprising an error correction means for restoring data of length k.
[0014]
A transmission program according to a seventh aspect of the present invention is a transmission program that causes a transmission device to transmit a transmission packet generated by encoding data using a forward error correction method, wherein the transmission program includes: At least receiving a transmission parameter selected from a reception interval of the transmission packet calculated from a reception state of the transmission packet, a discard rate of the transmission packet, and transmission throughput, and generating the transmission packet according to the transmission parameter It is characterized by realizing a packet generation function.
[0015]
The transmission program according to the invention of claim 8 is the transmission program according to claim 7, wherein the transmission parameters are a payload size P of the transmission packet, an interleave length T, and a data length. a frame construction function for constructing a k × T data matrix composed of k data and an interleave length T as one frame, and a code length (nk) for the data of k data constituting one frame. And an encoding function for generating an n × T data matrix including the error correction code, and an arrangement direction of the data to which the error correction code is added with respect to the n × T data matrix. Is an interleave function for performing time interleave processing according to the payload size P in the intersecting direction to generate packets, And assigning a sequence number to the packet, and realizing a header adding function of adding the sequence number, the interleave length T, the payload size P, the interleaving direction, and the error correction method as a header of the packet. I do.
[0016]
A receiving program according to the ninth aspect of the present invention provides a receiving program for causing a receiving apparatus to receive a transmission packet encoded using a forward error correction method, perform error correction, and then decode the transmission packet. A receiving function of storing the encoded transmission packet in a reception buffer; and monitoring a reception state of the transmission packet stored in the reception buffer, at least receiving the transmission packet. A packet monitoring function of acquiring an interval, a discard rate of the transmission packet, and transmission throughput as a monitoring result and returning the monitoring result to a transmission source of the transmission packet is realized.
[0017]
A reception program according to a tenth aspect of the present invention is the reception program according to the ninth aspect, wherein the data stored in the reception buffer is k × data having a data length k and an interleave length T. An error correction code having a code length (nk) is added to the T data matrix to generate an n × T data matrix including the error correction code. Sequence numbers assigned to transmission packets generated by performing time interleaving according to the payload size P in a direction intersecting with the arrangement direction of the data to which the correction code is added, and the interleave length T, the payload size P, the transmission packet to which the interleaving direction and the error correction method are added as a header, When there is a discarded transmission packet when reconstructing the one frame using the transmission packet to be transmitted, the sequence number of the discarded transmission packet is used as an error correction position of the data having the data length k. It is characterized by realizing an error correction function for restoring data of length k.
[0018]
Further, the transmission / reception program according to the eleventh aspect causes the transmission packet generated by encoding the data by the forward error correction method to be transmitted, and further, causes the encoded transmission packet to be received, and performs error correction. After being executed, the transmission / reception program for decoding the data, the reception status of the transmission packet is monitored, and at least the reception interval of the transmission packet, the discard rate of the transmission packet, and the transmission throughput are obtained as monitoring results. A packet monitoring function for returning the monitoring result to the transmission source of the transmission packet; and a parameter determination for receiving the monitoring result and selecting one transmission parameter from a plurality of transmission parameters set in advance according to the monitoring result. Function, according to the transmission parameter selected in the parameter determination function, Characterized in that to realize the packet generation function to generate serial transmission packet.
[0019]
According to the invention of claim 11, a transmission parameter for monitoring a reception interval of a transmission packet, a discard rate of the transmission packet, and a transmission throughput that changes according to a state of a transmission path, and generating a transmission packet according to a monitoring result. Is determined and a transmission packet is generated in accordance with the transmission parameter, so that the tolerance to packet discard and delay can be changed according to the status of the transmission path, and smooth data transmission can be realized.
[0020]
A transmission / reception program according to a twelfth aspect of the present invention is the transmission / reception program according to the eleventh aspect, wherein the transmission parameters are an interleave length T and a payload size P; A frame construction function for constructing a k × T data matrix composed of T as one frame, and adding an error correction code of code length (nk) to the data of data length k constituting one frame And an encoding function for generating an n × T data matrix including an error correction code, and the n × T data matrix is arranged in a direction intersecting with an arrangement direction of data to which an error correction code is added. An interleaving function that performs time interleaving processing according to the payload size P to generate a packet, and an interleaving function generated by the interleaving function. A header adding function for assigning a sequence number to the packet, adding the sequence number, the interleave length T, the payload size P, the interleaving direction, and the error correction method as a header of the packet, and reconstructing a frame from the received transmission packet At this time, it is determined whether or not there is a discarded transmission packet. If there is a discarded transmission packet, the sequence number of the discarded transmission packet is used as the error correction position of the data having the data length k. An error correction function for restoring k data is realized.
[0021]
According to the twelfth aspect of the present invention, a packet is generated by performing time interleave processing according to the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added, and the sequence number, the interleave length T, and the payload size P When a transmission packet is generated by adding the interleaving direction and the error correction method as a header of the packet, generating a transmission packet, transmitting the transmission packet to a destination, and reconstructing a frame using the transmission packet, when there is a discarded transmission packet Restores the data by using the sequence number of the discarded transmission packet as the error correction position of the data, so that the calculation for deriving the error locator polynomial and the error locator can be reduced, and the calculation load for decoding the data can be reduced. Can be reduced.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0023]
First, the configurations of the transmitting device 1 and the receiving device 6 of the present invention will be described with reference to FIG.
[0024]
The transmission device 1 includes a framing unit 2, a packet division unit 3, a packet generation unit 4, and a transmission parameter determination unit 5, as shown in FIG.
[0025]
The framing unit 2 includes a buffer memory, expands data received from the upper layer or the same layer in the memory according to the error correction code length and the interleave length determined by the transmission parameter determination unit 5, and forms one data frame. Has functions.
[0026]
The packet division unit 3 has a function of dividing one frame according to the payload length determined by the transmission parameter determination unit 5 and assigning a sequence number to each payload.
[0027]
The packet generation unit 4 has a function of adding a predetermined header to a payload, creating a transmission packet, and transmitting the packet to a peer layer or a lower layer.
[0028]
The transmission parameter determining unit 5 has a function of determining an interleave length and a payload length based on information from the receiving device 6.
[0029]
1B, the receiving device 6 includes a receiving buffer unit 7, an error determining unit 8, a data packet transmitting unit 11, an error position specifying unit 9, an error correcting unit 10, and a transmission packet monitoring unit 12. .
[0030]
The reception buffer unit 7 has a function of receiving transmission packets from a peer layer or a lower layer, and storing the received transmission packets for each frame in sequence number order.
[0031]
The error determination unit 8 determines whether there is a discarded transmission packet in the received information of one frame or, if there is a discarded transmission packet, the number of discarded packets within an error-correctable range, or the transmission packet containing only an error correction code. It has a function to determine whether it has been discarded.
[0032]
The data packet transmitting unit 11 has a function of transmitting a data packet to a peer layer or an upper layer.
[0033]
The error position specifying unit 9 has a function of specifying an error position with respect to the original data packet from the sequence number of the discarded transmission packet.
[0034]
The error correction unit 10 has a function of restoring a data packet when a transmission packet is discarded and the number of discards is within a range in which error correction is possible.
[0035]
The transmission packet monitoring unit 12 has a function of monitoring the reception buffer unit 7 and the error determination unit 8, acquiring the reception interval of transmission packets, the number of discarded packets, the throughput, and the like, and transmitting the acquisition result to the transmission device 1.
[0036]
<Transmission packet transmission processing>
First, a process of transmitting a transmission packet from the transmission device 1 will be described with reference to FIGS.
[0037]
In this embodiment, the minimum unit of data (unit of error correction) is referred to as “byte”. However, one byte is not limited to eight bits. As a coding method, a Reed-Solomon code (RS (n, k)) is used, the interleave length is T, and the data size of one frame is n × T bytes.
[0038]
First, the framing unit 2 determines the data size and the data development direction of one frame from the error correction method, error correction code length, data length, framing method, and interleave length recorded in the transmission parameter determination unit 5. Determine (step S01).
[0039]
The framing unit 2 receives a data packet having a data length of k bytes from an upper layer or a peer layer (step S02), adds an (nk) byte error correction code to the received data packet, and stores the data packet in a buffer memory. It is stored (step S03).
[0040]
As shown in FIG. 3, there are two methods of framing, (a) and (b). FIG. 3A shows a method of loading an error correction code in a direction in which a data packet is written, and FIG. 3B shows a method of loading an error correction code in a direction perpendicular to the direction in which a data packet is written. Is the way.
[0041]
Further, as shown in FIG. 3A, the case where the framing unit 2 receives a data packet in a state where an error correction code is added to the data packet in advance may be considered. In that case, the process of step S03 can be omitted.
[0042]
Next, it is determined whether a predetermined number of data packets has been read or one frame of data packets has been read (step S04). If one frame of data packets has not been read, the process returns to step S02 and the data packets are read. Receive. As shown in FIG. 3, data packets to which error correction codes have been added are sequentially stored in a buffer memory in the vertical direction. Steps S02 to S03 are repeated until a data packet for one frame is stored in the buffer memory.
[0043]
After reading the data for one frame, the packet division unit 3 reads the payload length recorded in the transmission parameter determination unit 5 (Step S05). The packet division unit 3 divides one frame into a plurality of payloads according to the read payload length, and assigns a sequence number to each payload (step S06).
[0044]
In FIG. 4, the payload size is 2T, and the direction in which one frame is divided into a plurality of payloads is the direction orthogonal to the direction in which the error correction code is added.
[0045]
Next, the packet generator 4 generates a transmission packet by adding a header to the payload (step S07), and sends the transmission packet to the same layer or a lower layer (step S08). Here, the header includes a sequence number, a payload length, an interleave length, an encoding method, an interleave method, and the like, as shown in the lower part of FIG.
[0046]
Next, it is determined whether or not all transmission packets for one frame have been transmitted (step S09). If not all transmission packets for one frame have been transmitted, a process of generating a transmission packet by adding a header to the payload. Return to The above processing (steps S07 to S08) is repeated until all transmission packets for one frame are transmitted. After transmitting all the transmission packets for one frame to the same layer or the lower layer, the processing shifts to the transmission processing of the next frame (step S10).
[0047]
<Transmission packet reception and decoding processing>
Next, a process in which the receiving device 6 receives a transmission packet will be described with reference to FIGS.
[0048]
When receiving the transmission packet, the reception buffer unit 7 stores the transmission packet in the buffer memory according to the information described in the header, and reconstructs the frame. At this time, if an error has occurred in the transmission packet, the packet is discarded (step S21). As shown in FIG. 6A, transmission packets are sequentially stored according to an interleaving method and a sequence number.
[0049]
Next, it is determined whether a predetermined number of transmission packets has been read or a timeout has occurred (step S22). If the predetermined number of transmission packets has not been read or if no timeout has occurred, the process returns to step S01. If a predetermined number of transmission packets has been read, or if a timeout has occurred, the error determination unit 8 determines whether the transmission packet has been discarded (step S23).
[0050]
When all the transmission packets constituting one frame have been received normally (in a state where no error has occurred), the error determination unit 8 transmits the data packet for one frame stored in the reception buffer unit 7 to the data packet. The data packet is transmitted to the unit 11, and the data packet transmitting unit 11 transmits the data packet to the same layer or an upper layer (step S24), and shifts to the reception processing of the next frame (step S25).
[0051]
If the transmission packet is discarded by 1 or more, the error determination unit 8 determines whether the number of transmission packet discards is within the correctable range and whether the transmission packet including the error correction code is not discarded (step S26). For example, in the case of RS (255, 239), error correction of 16 bytes can be performed.
[0052]
If the number of transmission packets for which error correction cannot be performed has been discarded, a request is made to the transmitting side to retransmit the transmission packet (step S27), and the process proceeds to the next frame reception process (step S28). If the transmission packet has been discarded but is within the correctable range, the error position identification unit 9 acquires the sequence number of the discarded transmission packet (step S29).
[0053]
Next, the error location specifying unit 9 transfers the sequence number of the discarded transmission packet to the error correction unit 10 as an error location of the original data packet, and the error correction unit 10 corrects the error of the data packet (step S30). In the example of FIG. 6B, the sequence number s3 is discarded, and in this example, the interleave length is 2T, so that the error positions of the data packet are Nos. 5 and 6.
[0054]
Next, after the error correction is completed, the error correction unit 10 transfers the data packet restored to normal information to the data packet transmission unit 11, and the data packet transmission unit 11 transmits the data packet to the same layer or an upper layer. It is sent (step S31).
[0055]
The data packet transmitting unit 11 determines whether all the data packets of one frame have been transmitted (step S32), and when all the data packets have been transmitted, shifts to the reception processing of the next frame (step S33). If not all data packets have been transmitted, the process returns to step S30.
[0056]
As described above, by performing the transmission packet transmission processing, the transmission packet reception, and the decoding processing, the packet is generated by performing the time interleaving processing according to the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added. Then, a transmission packet is generated by adding a sequence number, an interleave length T, a payload size, an interleaving direction, and an error correction method as a header of the packet, transmitted to a transmission destination, and a frame is reconstructed using the transmission packet. At this time, if there is a discarded transmission packet, the data packet is restored using the sequence number of the discarded transmission packet as an error correction position in the data packet. Can be reduced to decrypt data packets. It is possible to reduce the calculation load to be. Further, when a transmission packet consisting of only an error correction code is discarded, there is no need to perform error correction when decoding a data packet.
[0057]
<Transmission packet monitoring process>
Next, the processing of the transmission packet monitoring unit 12 of the receiving device 6 will be described with reference to FIG.
[0058]
First, when detecting the reception of the first transmission packet of one frame (step S41), the transmission packet monitoring unit 12 acquires the transmission source from the transmission packet (step S42).
[0059]
Next, each time a transmission packet is stored in the reception buffer unit 7, the transmission packet monitoring unit 12 calculates a reception interval from the reception time of the transmission packet stored immediately before (Step S43).
[0060]
Next, the transmission packet monitoring unit 12 obtains the determination result of the error determination unit 8 that determines whether a predetermined number of transmission packets has been received or a timeout has occurred (step S44).
[0061]
Next, when a predetermined number of transmission packets is received or when it is obtained that a timeout has occurred, the transmission packet monitoring unit 12 obtains the number of discarded packets from the error determination unit 8 (step S45). The transmission packet discard rate is calculated from the number of discarded transmission packets with respect to the number of transmission packets of one frame (step S46). Further, the transmission throughput is calculated from the reception interval between the first received transmission packet and the last received transmission packet, and the total data amount of one frame (step S47).
[0062]
Next, the transmission packet monitor unit 12 compares each calculation result with a preset threshold value to determine whether the condition for returning each calculation result to the transmission source is satisfied (step S48), and exceeds the predetermined condition. If so, the packet reception interval, the number of discarded packets, the discard rate, and the transmission throughput are transmitted to the transmission source (step S49). If it does not exceed the preset threshold value, the process shifts to the monitoring process of the reception state of another frame (step S50). Conditions for returning the monitoring result to the transmission source include: when the reception interval is disordered (jitter is generated); when the number of discarded packets in one frame is equal to or larger than a threshold; , The retransmission request for the same frame is repeated a threshold number of times, or the like.
[0063]
Note that each calculation result may be returned to the transmission source unconditionally without performing the determination processing in step S48.
[0064]
<Transmission parameter determination processing>
Next, the processing of the transmission parameter determination unit 5 of the transmission device 1 will be described with reference to FIGS.
[0065]
First, the transmission parameter determination unit 5 receives the packet reception interval, the number of discarded transmission packets, the transmission packet discard rate, and the transmission throughput from the receiving device 6 (step S61).
[0066]
Next, based on the received monitoring result, it is determined whether a condition for changing the transmission parameter is satisfied (step S62). The conditions for changing the transmission parameters are as follows: when the reception interval is disordered (jitter is generated), when the number of packets discarded in one frame is equal to or larger than a threshold, when the throughput is equal to or larger than the threshold for the transmission capacity. In this case, the request for retransmission of the same frame is repeated a threshold number of times, etc., but the threshold value in the transmitting device 1 may be the same value as the threshold value in the receiving device 6. A unique threshold value for the transmitting device 1 may be provided depending on the processing capability such as encoding and the transmission capacity.
[0067]
Next, if the condition for changing the transmission parameter is satisfied, the item in which the problem has occurred is extracted, and further, the corresponding action is taken from the data table shown in FIG. The plan is extracted, the transmission parameters are determined (step S63), and if the conditions for changing the transmission parameters are not satisfied, the process is terminated. The determined transmission parameters are transferred to the framing unit 2, the packet division unit 3, and the packet generation unit 4.
[0068]
FIG. 9 is an example of a data table that records a measure of interleave length and payload size for each state of the packet reception interval, transmission packet discard rate, and transmission throughput among the monitoring results, and a combination of the states. Yes, the transmission parameter determination unit 5 has. For example, when retransmission of one frame of data is performed in a state where jitter is occurring (state a in the data table), a transmission packet is generated with a large change in the payload size, and a new frame is transmitted. When transmitting, the data size of one frame is increased by increasing the interleave length, and the payload size is further increased.
[0069]
For example, as shown in FIG. 10, when the payload size is doubled from 2T to 4T, if one transmission packet is discarded, the number of places where error correction has to be performed doubles, and in one frame, The number of permissible discarded packets will be halved. However, by changing the payload size from 2T to 4T twice, the number of transmission packets constituting one frame is halved, and the data amount of the header is reduced by the halving of the number of transmission packets. Can be reduced.
[0070]
The countermeasure shown in FIG. 9 is not limited to this, and may differ from the countermeasure shown in FIG. 9 depending on the actual transmission path conditions. It is also conceivable to set a countermeasure in accordance with the number of transmission packets discarded specifically.
[0071]
As described above, the transmission packet monitoring process and the transmission parameter determination process monitor the reception interval of the transmission packet, the discard rate of the transmission packet, and the transmission throughput that change according to the status of the transmission path, and transmit the transmission packet according to the monitoring result. Since transmission parameters to be generated are determined and transmission packets are generated according to the transmission parameters, it is possible to change the resistance to packet discarding and delay according to the state of the transmission path, and realize smooth data transmission. Can be.
[0072]
In the present embodiment, the transmitting device 1 has a function of determining a transmission parameter. However, the receiving device 6 may have a function of determining a transmission parameter. It is also conceivable that the transmission device determines transmission parameters so as to be optimal and transmits the transmission parameters to the transmission device 1.
[0073]
Further, as an embodiment of the present invention, a transmission / reception device 136 including a transmission device 1 and a reception device 6 as shown in FIG. 11 can be considered. In the case of performing mutual communication using the transmission / reception device 136, the transmission side and the reception side perform the above-described operations by the transmission packet transmission processing, transmission packet reception and decoding processing, transmission packet monitoring processing, and transmission parameter determination processing described above. The same effect as in the embodiment can be obtained.
[0074]
【The invention's effect】
As described above, according to the present invention, the reception state of a transmission packet that changes according to the status of a transmission path is monitored, a transmission parameter for generating the transmission packet is determined according to the monitoring result, and the transmission parameter is determined. Since the transmission packet is generated according to the parameters, the tolerance to packet discard and delay can be changed according to the status of the transmission path, and smooth data transmission can be realized.
[0075]
In addition, a packet is generated by performing time interleave processing according to the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added, and a sequence number, an interleave length T, a payload size P, an interleave direction, an error correction A transmission packet is generated by adding the method as a header of the packet, transmitted to a destination, and when reconstructing a frame using the transmission packet, if there is a discarded transmission packet, the discarded transmission packet is used. Since the data is restored using the packet sequence number as the error correction position of the data, the calculation for deriving the error locator polynomial and the error locator can be reduced, and the calculation load for decoding the data can be reduced.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a transmitting device and a receiving device.
FIG. 2 is a flowchart illustrating a procedure of a transmission packet transmission process of the transmission device.
FIG. 3 is a schematic diagram illustrating framing and encoding of data performed by a framing unit.
FIG. 4 is a schematic diagram illustrating an interleaving process performed by a packet division unit and a packet generation unit and a transmission packet.
FIG. 5 is a flowchart showing a procedure of a transmission packet reception and decoding process of the receiving device.
FIG. 6 is a schematic diagram illustrating reconstruction of a frame.
FIG. 7 is a flowchart illustrating a procedure of a monitoring process of monitoring a transmission packet by a transmission packet monitoring unit;
FIG. 8 is a flowchart illustrating a procedure of processing for determining a transmission parameter by a transmission parameter determining unit.
FIG. 9 is a table showing a relationship between a monitoring result and a measure for dealing with a transmission parameter;
FIG. 10 is a schematic diagram illustrating a relationship between a payload size of a transmission packet and an error correction position.
FIG. 11 is a functional block diagram of a transmission / reception device.
[Explanation of symbols]
1 transmitting device
2 Frame conversion unit
3 Packet division unit
4 Packet generator
5 Transmission parameter determination unit
6 Receiver
7 Receive buffer
8 Error judgment unit
9 Error location identification unit
10 Error correction unit
11 Data packet sending unit
12 Transmission packet monitor
13 Transceiver

Claims (12)

A transmission device that encodes data by a forward error correction method to generate a transmission packet and transmits the transmission packet,
The transmitting device,
Upon receiving a transmission parameter selected from at least a reception interval of the transmission packet calculated from a reception state of the transmission packet at the transmission destination, a discard rate of the transmission packet, and a transmission throughput, generating the transmission packet in accordance with the transmission parameter Packet generating means for performing
A transmission device comprising: The transmitting device,
When at least the reception interval of the transmission packet, the discard rate of the transmission packet, and the transmission throughput are received from the destination of the transmission packet as a monitoring result, one transmission is performed from a plurality of transmission parameters set in advance according to the monitoring result. The transmission device according to claim 1, further comprising parameter determination means for selecting a parameter. The transmission parameters are a payload size P of the transmission packet and an interleave length T,
Frame forming means for forming a data matrix of k × T comprising data of data length k and interleave length T as one frame;
Coding means for adding an error correction code of code length (nk) to the data of data length k constituting the one frame to generate an nxT data matrix including the error correction code;
Interleaving means for performing a time interleaving process on the n × T data matrix in accordance with the payload size P in a direction intersecting with an arrangement direction of data to which an error correction code is added, to generate a packet;
Header adding means for allocating a sequence number to the packet generated by the interleaving means, adding the sequence number, the interleaving length T, the payload size P, the direction of the interleaving, and the error correction method as a header of the packet;
The transmission device according to claim 1, further comprising: A receiving apparatus for receiving a transmission packet encoded using a forward error correction method, performing error correction, and then decoding the transmission packet,
The receiving device,
A reception buffer for storing the encoded transmission packet;
The reception state of the transmission packet stored in the reception buffer is monitored, and at least the reception interval of the transmission packet, the discard rate of the transmission packet, and the transmission throughput are obtained as monitoring results, and the monitoring is performed to the transmission source of the transmission packet. Packet monitoring means for returning a result,
A receiving device comprising: The receiving device,
When the packet monitoring means obtains the monitoring result, a parameter for selecting one transmission parameter from a plurality of transmission parameters set in advance according to the monitoring result and returning the transmission parameter to the transmission source of the transmission packet The receiving device according to claim 4, further comprising a determination unit. The data stored in the reception buffer is obtained by adding an error correction code having a code length (nk) to a k × T data matrix including a data length k and an interleave length T to generate an error correction code. An n × T data matrix is generated, and the n × T data matrix is subjected to time interleave processing in accordance with the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added. The transmission packet obtained by adding, as a header, a sequence number assigned to each transmission packet, and the interleave length T, the payload size P, the direction of the interleave, and an error correction method to the transmission packet,
When reconstructing the one frame using the transmission packet stored in the reception buffer, if there is a discarded transmission packet, the sequence number of the discarded transmission packet is replaced with the sequence number of the data having the data length k. The receiving apparatus according to claim 4, further comprising an error correction unit that restores the data having the data length k as an error correction position. A transmission program that causes a transmission device to transmit a transmission packet generated by encoding data using a forward error correction method,
The transmission program,
A transmission parameter selected from at least a reception interval of the transmission packet calculated from a reception state of the transmission packet of the transmission destination, a discard rate of the transmission packet, and a transmission throughput is received, and the transmission packet is generated according to the transmission parameter. Packet generation function,
A transmission program characterized by realizing: The transmission parameters are a payload size P of the transmission packet and an interleave length T,
A frame configuration function for configuring a data matrix of k × T including data of data length k and interleave length T as one frame;
An encoding function of adding an error correction code having a code length (nk) to the data having the data length k forming the one frame to generate an nxT data matrix including the error correction code;
An interleave function of performing time interleave processing on the n × T data matrix in accordance with the payload size P in a direction intersecting with an arrangement direction of data to which an error correction code is added, to generate a packet;
A header adding function of assigning a sequence number to the packet generated by the interleaving means, adding the sequence number, the interleave length T, the payload size P, the direction of the interleave, and the error correction method as a header of the packet;
8. The transmission program according to claim 7, wherein: A receiving program for causing the receiving device to receive the transmission packet encoded using the forward error correction method, perform error correction, and then decode the transmission packet,
The receiving program,
A storage function of storing the encoded transmission packet in a reception buffer,
The reception status of the transmission packet stored in the reception buffer is monitored, at least the reception interval of the transmission packet, the discard rate of the transmission packet, and the transmission throughput are obtained as monitoring results, and the transmission source of the transmission packet performs the monitoring. A packet monitoring function to return the result,
A receiving program characterized by realizing: The data stored in the reception buffer is obtained by adding an error correction code having a code length (nk) to a k × T data matrix including a data length k and an interleave length T to generate an error correction code. An n × T data matrix is generated, and the n × T data matrix is subjected to time interleave processing in accordance with the payload size P in a direction intersecting with the arrangement direction of the data to which the error correction code is added. The transmission packet obtained by adding, as a header, a sequence number assigned to each transmission packet, and the interleave length T, the payload size P, the direction of the interleave, and an error correction method to the transmission packet,
When reconstructing the one frame using the transmission packet stored in the reception buffer, if there is a discarded transmission packet, the sequence number of the discarded transmission packet is replaced with the data of the data length k. 10. The receiving program according to claim 9, wherein an error correction function for restoring the data having the data length k as an error correction position is realized. A transmission / reception device that causes a transmission / reception device to transmit a transmission packet generated by encoding data using a forward error correction method, further receives an encoded transmission packet, performs error correction, and then decodes the data. A program,
A packet monitoring function for monitoring a reception state of the transmission packet, acquiring at least a reception interval of the transmission packet, a discard rate of the transmission packet, and a transmission throughput as a monitoring result, and returning the monitoring result to a transmission source of the transmission packet. When,
A parameter determination function of receiving the monitoring result and selecting one transmission parameter from a plurality of transmission parameters set in advance according to the monitoring result;
A packet generation function for generating the transmission packet according to the transmission parameter selected by the parameter determination function,
A transmission / reception program characterized by realizing: The transmission parameters are an interleave length T and a payload size P,
A frame configuration function for configuring a data matrix of k × T including data of data length k and interleave length T as one frame;
An encoding function of adding an error correction code having a code length (nk) to the data having the data length k forming the one frame to generate an nxT data matrix including the error correction code;
An interleave function of performing time interleave processing on the n × T data matrix in accordance with the payload size P in a direction intersecting with an arrangement direction of data to which an error correction code is added, to generate a packet;
A header adding function for allocating a sequence number to the packet generated by the interleave function, adding the sequence number, the interleave length T, the payload size P, the interleave direction, and the error correction method as a header of the packet;
When reconstructing a frame from a received transmission packet, it is determined whether there is a discarded transmission packet, and if there is a discarded transmission packet, the sequence number of the discarded transmission packet is set to the data length k. An error correction function for restoring the data having the data length k as an error correction position of data;
The transmission / reception program according to claim 11, wherein:

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