JP2017011432A - Transmitter, receiver and transceiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely transmit data having high priority order with a low delay without failure, and to achieve well-balanced and efficient transmission as a whole.SOLUTION: A distribution storage part 10 of a transmitter 1-1 distributes each packet according to priority. An error detection and error correction coding unit 12-1 codes a packet having high priority order with a code having high correction performance. An error detection and error correction coding unit 12-2 codes a packet having low priority order with a code having low correction performance. A frame generation unit 14 stores a predetermined amount of packets of high priority order into a frame so that each packet of the high priority order is transmitted at a transmission rate of a predetermined speed, and stores each packet of the low priority order into the residual part of the frame, to perform retransmission processing according to a preset number of retransmission restriction times (a smaller number of times is set to the packet of the high priority order than to the packet of the low priority order).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmitter that transmits data such as video, audio, and computer files, a receiver that receives the data, and a transceiver that transmits and receives the data.

  Conventionally, a transmitter that converts data such as video, audio, and computer files into a wireless signal and transmits the wireless signal, a receiver that receives the wireless signal and converts it into original data, and these transmitters A transceiver having a receiver function is also known. In such a transmission system, for example, an ARQ (automatic retransmission request) protocol is used in order to realize highly reliable transmission.

  For example, the transmitter receives a packet in which data such as video is stored, performs error detection and error correction coding on the packet, converts the packet into a radio signal, and transmits the signal. The receiver receives a radio signal and performs error correction decoding on the packet to detect a packet error. Here, when the receiver determines that there is no packet error and the packet is normally received, the receiver returns an ACK. When the receiver determines that there is a packet error and the packet cannot be normally received, the retransmission request (NACK) Reply. When the transmitter receives a retransmission request, the transmitter retransmits the packet within a preset number of retransmission limits.

  Various techniques are used for such transmitters, receivers, and transceivers to transmit and receive data such as video via wireless sections. For example, a technique is known in which the delay time of data transmitted from a transmitter to a receiver is kept within an allowable time, and packet loss is prevented (see, for example, Patent Document 1).

  In addition, a technique is known in which data to be transmitted is classified into real-time information and non-real-time information, and when the information is multiplexed and transmitted, information whose expiration date has passed is not transmitted ( For example, see Patent Document 2). Thereby, useless retransmission can be eliminated and transmission efficiency can be improved.

  In addition, when the transmission target data is divided into real-time information and non-real-time information and transmitted by TCP (Transmission Control Protocol), the information is preferentially transmitted by reducing the maximum number of real-time information transmissions. A technique is known (see, for example, Patent Document 3). Thereby, overhead can be reduced.

  Also, the MAC (Medium Access Control) HARQ (Hybrid Automatic Repeat Request) process and the higher RLC (Radio Link Control) ARQ process are combined to set the maximum number of retransmissions based on QoS (Quality of Service) data. A technique for performing adaptive modulation or the like by RM (retransmission management) is known (see, for example, Patent Document 4). Thereby, overhead and latency can be reduced.

  Also, with HASP of HDSPA (High Speed Downlink Packet Connection) as a background, even if the quality of the communication channel is degraded when ARQ is used, multiple HARQ processes are executed in order to quickly transmit high priority packets. A technique for quickly performing priority transmission in a re-sending process is known (see, for example, Patent Document 5).

Japanese Patent Application Laid-Open No. 07-221789 Japanese Patent Laid-Open No. 11-098128 JP 2006-295847 A Japanese Patent No. 4933555 Japanese Patent No. 5150520

  However, in the transmission system using the above-described ARQ protocol, the transmitter needs to wait until it receives ACK from the receiver after transmitting data, which increases the delay. In particular, when the number of data retransmissions increases, data with high priority, such as highly urgent data and data to be transmitted quickly, cannot be transmitted from the transmitter to the receiver within a predetermined time. Also, there is a problem that the transmission time varies.

  Here, although it is possible to use the technique of the said patent documents 1-5, it is not enough as follows. For example, the technique of Patent Document 1 does not consider HARQ, and packets may be discarded at the receiver, so transmission efficiency is not always improved. Further, in the technique of Patent Document 2, since the block management information to be transmitted becomes large, the overhead increases.

  The technique of Patent Document 3 is characterized in that the transmission / reception history of each packet is managed by extracting the sequence number of the upper layer. However, analysis processing in a lower layer is required separately, and a complicated configuration is required. Further, with the techniques of Patent Documents 4 and 5, it is impossible to reduce overhead due to a control signal or the like and to quickly transmit a high priority packet with a simple configuration and processing.

  As described above, in the techniques of Patent Documents 1 to 5, transmission efficiency is lowered and overhead is increased, so that data with high priority may not be reliably transmitted. In addition, when transmitting all data from high priority data to low data, there is a problem that it is difficult to realize balanced and efficient transmission as a whole. In addition, it has been desired to realize transmission of a plurality of data having different priorities with a simple configuration and processing.

  Therefore, the present invention has been made to solve the above-described problems, and the purpose of the present invention is to transmit data with high priority without failing with low delay and without failure when transmitting data with different priority. An object of the present invention is to provide a transmitter, a receiver, and a transmitter / receiver capable of realizing balanced and efficient transmission as a whole.

  In order to solve the above-mentioned problem, the transmitter of claim 1 inputs a packet including a header and data in which priority is stored, performs error detection and error correction coding on the packet, stores the packet in the frame, In the transmitter for transmitting the packet to the receiver, the packet is distributed according to the priority order, and the higher the priority is, the higher the correction priority is for the packet distributed by the distribution part. And error detection and error correction encoding using a code with lower correction performance as the priority is lower, generating parity bits, and generating a packet composed of the header, data, and parity bits And an error correction encoding unit, and a packet that has been subjected to error detection and error correction encoding by the error detection and error correction encoding unit. The error detection and error correction encoded packets are stored in the frame so that the high priority predetermined packets are transmitted at a predetermined transmission rate, and the higher priority packets are smaller in number. In accordance with the retransmission request from the receiver, the packet corresponding to the retransmission request is stored in the frame within the range of the number of retransmission restrictions set to a larger number as the lower priority packet is set, And a frame generation unit for generating a frame.

  The transmitter according to claim 2 inputs a packet composed of a header and data storing priorities, performs error detection and error correction coding on the packet, stores the packet in a frame, and transmits the frame to the receiver In the transmitter, error detection and error correction coding is performed on the packet using a predetermined code, parity bits are generated, and error detection and error correction are generated to generate a packet including the header and data and the parity bits. An encoding unit, a distribution unit that distributes packets that have been subjected to error detection and error correction encoding by the error detection and error correction encoding unit according to the priority, and a packet that is distributed by the distribution unit The predetermined packet having a low priority is divided into the header and data and the parity bit, and Among the packets distributed by the allocating unit and the dividing unit that divides each bit into a predetermined number of divided parity bits, so that the predetermined packet with the higher priority is transmitted at a predetermined transmission rate. A predetermined packet having a higher priority is stored in the frame, and for the predetermined packet having a lower priority, the header and data divided by the dividing unit or the divided parity bit is stored in the frame, and the priority is also given. The packet corresponding to the retransmission request in accordance with the retransmission request from the receiver within the range of the retransmission limit number set to a smaller number as the higher priority packet and the higher number as the lower priority packet, Store the header and data or the divided parity bit in the frame to generate the frame A frame generation unit, and for the predetermined packet having a low priority, first, the header and data are stored in the frame and transmitted, and at each retransmission, the predetermined number of divided parity bits One divided parity bit is stored in the frame and transmitted.

  Furthermore, the receiver of claim 3 receives the frame transmitted from the transmitter of claim 1, extracts a packet from the frame, performs error correction decoding, determines a packet error, and sends a return frame to the transmitter. In the receiving receiver, the packet is extracted from the frame, and the packet extraction and distribution unit that distributes the packet according to the priority order, and the packet that is distributed by the packet extraction and distribution unit, the higher the priority is, When a code with high correction performance is used and error correction decoding is performed using a code with lower correction performance as the priority is lower, whether there is a packet error, and when there is no packet error, An error correction decoding and error detection unit for outputting a packet consisting of a header and data, and the error correction decoding and error detection unit; If it is determined that there is a packet error, the packet with the higher priority is set to a smaller number, and the packet with the lower priority is set to a larger number within the range of the retransmission limit number. A return frame generation unit that generates a return frame including a retransmission request for retransmitting the determined packet.

  The receiver according to claim 4 receives the frame transmitted from the transmitter according to claim 2, extracts the packet, header and data, and the divided parity bit from the frame, performs error correction decoding, and determines a packet error. Then, in the receiver that transmits a return frame to the transmitter, a packet having a high priority is extracted from the frame, and a predetermined number of low-priority packet headers and data, or a low-priority packet parity bit is used. A packet extraction and distribution unit that takes out the divided parity bits divided into two, and distributes them to the high priority packet and the low priority packet header and data, or the low priority packet divided parity bit And the priority distributed by the packet extraction and distribution unit First, an error correction decoding is performed on a higher-order packet with a predetermined code to determine the presence or absence of a packet error. When it is determined that there is no packet error, a first packet including a header and data after decoding is output. When the header and data of the low priority packet are sorted by the error correction decoding and error detection unit and the packet extraction and sorting unit, error correction is performed with the predetermined code using the header and data. When decoding is performed, it is determined whether there is a packet error, and when it is determined that there is no packet error, a packet composed of the header and data after decoding is output, and the packet extraction and distribution unit When divided parity bits are allocated, the header and data of the same packet as the low priority packet and the current allocation are allocated. Using the divided parity bits divided, or using the same packet header and data as the low priority packet, the previously distributed divided parity bits, and the divided parity bits distributed this time, Second error correction decoding and error outputting a packet composed of a header and data after decoding when error correction decoding is performed with the predetermined code, and it is determined whether there is no packet error. If the detection unit and the first error correction decoding and error detection unit determine that there is a packet error, the higher priority packet is set to a smaller number, and the lower priority packet is set to a higher number. Resend required to retransmit the packet determined to have the packet error within the specified number of retransmission limits. A packet that is determined to have the packet error within the range of the number of retransmission limits when the second error correction decoding and error detection unit determines that there is a packet error. And a return frame generation unit that generates a return frame including a retransmission request for transmitting a divided parity bit that has not been transmitted yet.

  Furthermore, the transmitter / receiver according to claim 5 inputs a packet including a header and data storing priorities, performs error detection and error correction coding on the packet, stores the packet in a frame, and transmits the frame A reception processing unit that receives a frame, extracts a packet from the frame, performs error correction decoding, determines a packet error, and transmits a return frame, wherein the transmission processing unit includes the packet For the packets distributed by the distribution unit according to the priority, the higher the priority, the higher the correction performance code is used, and the lower the priority, the correction performance A low code is used to perform error detection and error correction coding, generate parity bits, the header and data, and the parity. An error detection and error correction encoding unit that generates a packet consisting of a single bit, and among the packets that have been error detected and error correction encoded by the error detection and error correction encoding unit, a predetermined packet with a high priority is predetermined The error detection and error correction encoded packets are stored in the frame so that the higher priority packets are set to a smaller number, and the lower priority packets are A frame generation unit that stores the packet corresponding to the retransmission request in the frame and generates the frame in accordance with a retransmission request from another transmitter / receiver within a range of the retransmission limit number set to a large number; And the reception processing unit extracts a packet from the frame and distributes the packet according to a priority order. And the sorting unit and the packet sorted by the packet extraction and sorting unit, a code having a higher correction performance is used as the priority is higher, and a code having a lower correction performance is used as the priority is lower. Performing error correction decoding, determining the presence or absence of a packet error, and determining that there is no packet error, an error correction decoding and error detection unit that outputs a packet including a header and data after decoding; and the error correction decoding and If it is determined by the error detection unit that there is a packet error, the higher priority packet is set to a smaller number, and the lower priority packet is set to a higher number within the range of the retransmission limit number. A return frame generation unit that generates a return frame including a retransmission request for retransmitting a packet determined to have an error; It is provided with.

  The transceiver according to claim 6 is a transmission processing unit that receives a packet including a header and data storing priorities, performs error detection and error correction coding on the packet, stores the packet in a frame, and transmits the frame A reception processing unit that receives a frame, extracts a packet, a header and data, and a divided parity bit from the frame, performs error correction decoding, determines a packet error, and transmits a return frame. The transmission processing unit performs error detection and error correction coding on the packet using a predetermined code, generates a parity bit, and generates a packet including the header, data, and the parity bit. And an error correction encoder, and an error detection and error correction code by the error detection and error correction encoder. And the sorting unit that sorts the packets into the priority order, and among the packets sorted by the sorting unit, the predetermined packet having the low priority order is assigned to the header and data and the parity bit. A dividing unit that divides the parity bit into a predetermined number of divided parity bits and a packet that has a higher priority among packets distributed by the allocating unit are transmitted at a predetermined transmission rate. As described above, the predetermined packet having the higher priority is stored in the frame, and the header and data divided by the dividing unit or the divided parity bit is added to the frame for the predetermined packet having the lower priority. In addition to storing, the lower priority packet is set to a smaller number, and the lower priority packet is set. The packet, the header and data, or the divided parity bits corresponding to the retransmission request are stored in the frame in accordance with the retransmission request from another transmitter / receiver within the range of the retransmission limit number set to a larger number. A frame generation unit configured to generate the frame, and for the predetermined packet having a low priority, first, the header and data are stored in the frame and transmitted, and at the time of retransmission, the predetermined number of divisions The first divided parity bit of the parity bits is stored in the frame and transmitted, and the second divided parity bit of the predetermined number of divided parity bits is stored and transmitted in the next retransmission. At the time of further retransmission, another divided parity bit is stored in the frame and transmitted, and the reception processing unit Taking out a packet with a higher priority, taking out the divided parity bits obtained by dividing a header and data of a packet with a lower priority, or a parity bit of a packet with a lower priority into a predetermined number, and a packet with a higher priority, The packet extraction and distribution unit that distributes the header and data of the low priority packet or the divided parity bits of the low priority packet, and the high priority packet that is distributed by the packet extraction and distribution unit On the other hand, error correction decoding is performed with a predetermined code to determine the presence or absence of a packet error, and when it is determined that there is no packet error, a first error correction decoding that outputs a packet consisting of a header and data after decoding And the error detection unit and the packet extraction and distribution unit If the header and data of the packet are distributed, error correction decoding is performed using the header and data using the predetermined code, whether there is a packet error, and when it is determined that there is no packet error, When a packet consisting of a later header and data is output, and when the divided parity bits of the lower priority packet are distributed by the packet extraction and distribution unit, the header and data of the same packet as the lower priority packet, And using the divided parity bit distributed this time, or the header and data of the same packet as the low priority packet, the previously distributed divided parity bit, and the divided parity bit distributed this time Then, error correction decoding is performed with the predetermined code, and there is a packet error. And when it is determined that there is no packet error, a second error correction decoding and error detection unit that outputs a packet including a header and data after decoding, and the first error correction decoding and error detection unit If it is determined that there is a packet error, the higher priority packet is set to a smaller number, and the lower priority packet is set to a higher number of retransmission limits within the range of the number of retransmission limits. When generating a return frame including a retransmission request for retransmitting the determined packet and determining that there is a packet error by the second error correction decoding and error detecting unit, within the range of the retransmission limit number, A return including a retransmission request for transmitting a divided parity bit that has not yet been transmitted in the packet determined to have the packet error. And a return frame generation unit for generating a frame.

  As described above, according to the present invention, when data with different priorities is transmitted, data with high priorities can be reliably transmitted without failure with a low delay, and the overall balance is achieved. Efficient transmission can be realized.

3 is a block diagram illustrating a configuration example of a transmitter according to Embodiment 1. FIG. It is a figure explaining the process example of a packet generation part. It is a figure explaining the process example of a distribution storage part. It is a figure explaining the process example of an error detection and an error correction encoding part. It is a figure which shows the structural example of a flame | frame. 3 is a block diagram illustrating a configuration example of a receiver according to Embodiment 1. FIG. It is a figure explaining the example of a process of an error correction decoding and an error detection part. 6 is a block diagram illustrating a configuration example of a transmitter according to Embodiment 2. FIG. It is a figure explaining the process example of a distribution part, a storage part, and a division | segmentation storage part. 6 is a block diagram illustrating a configuration example of a receiver according to Embodiment 2. FIG. It is a figure explaining the example of a process of a distribution storage part, an error correction decoding, and an error detection part.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The first embodiment described below performs error correction on a high priority packet with a code having high correction performance, suppresses retransmission processing to a small number, and has low correction performance on a low priority packet. Error correction is performed using a code.

  In the second embodiment, error correction is performed on all packets with a predetermined code, and retransmission processing is suppressed to a small number for packets with high priority. The data is divided into a predetermined number of parity bits and transmitted in divided units.

[Example 1]
First, Example 1 will be described. As described above, in the first embodiment, error correction is performed on a high priority packet with a code having high correction performance, the number of retransmission processes is limited to a small number, and correction performance is low for a low priority packet. Error correction is performed using a code. The transmitter and receiver according to the first embodiment realize hybrid ARQ (HARQ) processing that combines FEC (error correction code) processing and ARQ (automatic retransmission request) processing.

[Transmitter / Example 1]
A transmitter according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a configuration example of a transmitter according to the first embodiment. The transmitter 1-1 includes an allocation storage unit 10, buffers 11-1 and 11-2, error detection and error correction encoding units 12-1 and 12-2, buffers 13-1 and 13-2, and frame generation. Unit 14, transmission unit 15, and reception unit 16. The transmitter 1-1 is a device that transmits video, audio, computer files, and the like via a wireless section. For example, the transmitter 1-1 is provided in an FPU (Field Pick-up Unit) used by a broadcaster. The same applies to a transmitter 1-2 of Example 2 described later.

  The transmitter 1-1 receives a packet from a packet generator of an encoder (not shown) provided outside. FIG. 2 is a diagram illustrating a processing example of the packet generation unit. The packet generator inputs data such as video, audio, and computer files (step S201), and divides the data into arbitrary sizes (fixed length or variable length) (step S202).

  The packet generation unit sets a priority order, a packet order, and the like for each divided data, stores these pieces of information in a header, and generates a packet by adding the header to the data (step S203). Then, the packet generation unit outputs a packet including a header and data to the transmitter 1 (step S204).

  The priority indicates the order of urgency of the packet when transmitting data, and the packet order indicates the order in which packets are transmitted and received, and is set for each packet having the same priority. For example, if the pre-division data input to the packet generator is composed of IP packets, use the priority index stored in the DSCP (Differentiated Services Code Point) of the IP packet header, etc. Set packet priority.

  As described above, the packet generated by the packet generation unit of the encoder is output to the transmitter 1-1 with the priority, the packet order, and the like stored in the header.

  Returning to FIG. 1, the distribution storage unit 10 of the transmitter 1-1 receives a packet from a packet generation unit of an encoder (not shown), distributes the packet according to the priority order, and distributes the distributed packet to the buffer 11- 1, 11-2.

  FIG. 3 is a diagram illustrating a processing example of the distribution storage unit 10. The distribution storage unit 10 receives a packet including a header and data (step S301), extracts a priority from the packet header, and distributes the packet to a packet having a high priority and a packet having a low priority based on the priority. (Step S302). Then, the distribution storage unit 10 stores packets with high priority in the buffer 11-1, and stores packets with low priority in the buffer 11-2 (step S303).

  For example, when the priority is set as a numerical value, the distribution storage unit 10 compares the numerical value of the priority extracted from the header of the packet with a preset threshold value. If the allocation storage unit 10 determines that the numerical value of the priority order is equal to or greater than the threshold value, the distribution storage unit 10 stores the packet in the buffer 11-1 as a packet having a high priority order. On the other hand, if the distribution storage unit 10 determines that the numerical value of the priority order is smaller than the threshold value, the distribution storage unit 10 stores the packet as a low priority packet in the buffer 11-2. As described above, in FIG. 1, the buffer 11-1 is used as a storage unit that stores packets with high priority, and the buffer 11-2 is used as a storage unit that stores packets with low priority.

  A plurality of different threshold values may be used to classify the priority order into 3 or more. In this case, the distribution storage unit 10 divides the packets into three or more groups having different priorities based on the numerical values of the priorities extracted from the packet headers and a plurality of different threshold values set in advance. The distribution storage unit 10 stores the grouped packets in a buffer provided for each group. The transmitter 1-1 includes a buffer according to the priority classification, an error detection and error correction coding unit. The same applies to a receiver 2-1 described later and a transmitter 1-2 and a receiver 2-2 of the second embodiment.

  Returning to FIG. 1, the error detection and error correction encoding units 12-1 and 12-2 read packets from the buffers 11-1 and 11-2, and perform error detection and error detection using different error detection and error correction codes. Error encoding is performed, and the encoded packets are stored in the buffers 13-1 and 13-2.

  FIG. 4 is a diagram for explaining a processing example of the error detection and error correction encoding units 12-1 and 12-2. The error detection and error correction coding unit 12-1 reads a packet having a high priority from the buffer 11-1 (step S401a), and the packet has higher correction performance than the error detection and error correction coding unit 12-2. The error detection and error correction codes are used to perform error detection and error correction coding (step S402a), generate parity bits, and add the parity bits to the packet header and data (step S403a). Then, the error detection and error correction encoding unit 12-1 stores, in the buffer 13-1, a packet having a high priority after encoding (a packet including a header, data, and parity bits). Note that the error correction code in FIG. 4 is an example of a systematic code (a code that can clearly distinguish an information sequence and a parity sequence before encoding: a Hamming code, a Reed-Solomon code, etc.). The same applies to a code in which the previous information sequence and the parity sequence cannot be clearly distinguished (such as a convolutional code that does not include a sequence that does not pass through the encoder).

  The error detection and error correction encoding unit 12-2 reads a packet having a low priority from the buffer 11-2 (step S401b), and the correction performance of the packet is lower than that of the error detection and error correction encoding unit 12-1. The error detection and error correction codes are used to perform error detection and error correction coding (step S402b), generate parity bits, and add the parity bits to the packet header and data (step S403b). Then, the error detection and error correction encoding unit 12-2 stores a low-priority packet (a packet including a header, data, and parity bits) after encoding in the buffer 13-2. Since the amount of parity bits generated by the error detection and error correction encoding unit 12-1 generally depends on the error correction performance, the amount of parity bits generated by the error detection and error correction encoding unit 12-2 There are also many.

  The error detection and error correction code is a code that can be subjected to error correction decoding on the decoding side and further error detection. As the error detection and error correction code, a code having both error correction and error detection functions, such as a Reed-Solomon code (RS code), is used. In addition, when the error detection and error correction coding unit is 3 or more, the error detection and error correction code having the higher correction performance is used for the higher priority packet, and the error detection and error having the lower correction performance is used for the lower priority packet. A correction code is used.

  Thereby, a packet having a higher priority is more resistant to transmission errors by using a high-performance error correction code. Further, a packet with a higher priority can be realized with a low delay by reducing the number of retransmission restrictions.

  Returning to FIG. 1, the frame generation unit 14 reads packets from the buffers 13-1 and 13-2, and the packets with high priority read from the buffer 13-1 are transmitted at a transmission rate of a predetermined speed. A predetermined amount of packets read from the buffer 13-1 is preferentially stored in a frame so as to ensure a constant transmission rate. In addition, the frame generation unit 14 stores the packet read from the buffer 13-2 in the remaining part of the frame. Then, the frame generation unit 14 generates a frame storing the packets read from the buffers 13-1 and 13-2 and outputs the frame to the transmission unit 15.

  The frame generation unit 14 stores the high priority packet read from the buffer 13-1 at a predetermined position of the frame based on the preset position information, and the priority order read from the buffer 13-2. Low packets may be stored at predetermined positions in the frame. The preset position information includes a packet having a high priority and a packet having a high priority so as to ensure a constant transmission rate by transmitting the packet having a high priority read from the buffer 13-1 at a transmission rate of a predetermined speed. Information indicating where in the frame a packet with low priority is stored is defined.

  The frame generation unit 14 receives a return frame from the reception unit 16 and extracts an ACK or a retransmission request (NACK) included in the return frame. When the frame generation unit 14 extracts the ACK, the frame generation unit 14 does not retransmit the packet corresponding to the ACK.

  On the other hand, when the frame generation unit 14 extracts a retransmission request, when the number of retransmissions is less than or equal to a preset retransmission limit number for a packet corresponding to the retransmission request, the frame generation unit 14 sets a new number of retransmissions for the header. And a packet corresponding to the retransmission request is stored in the frame. The frame generation unit 14 performs predetermined error processing when the number of retransmissions exceeds a preset number of retransmission limits.

  Here, as the number of retransmission restrictions, a smaller number is set in advance for a packet with a higher priority, and a larger number is set in advance for a packet with a lower priority. That is, the number of retransmission restrictions for a high priority packet is smaller than that for a low priority packet, and the number of retransmission restrictions for a low priority packet is larger than that for a high priority packet. The retransmission limit number indicates the maximum number of times that can be retransmitted by the transmitter 1-1 when the later-described receiver 2-1 cannot correctly decode the packet. 0 may be set as the retransmission limit count for a packet with high priority.

  Generally, in the wireless section having bidirectionality, when an error occurs during packet transmission, a packet retransmission request is made in the receiver 2-1, which will be described later, and the packet error can be recovered. However, there is a possibility that the packet error cannot be recovered even if the transmitter 1-1 resends many times in a radio section of a poor environment. In this case, the packet delay time can be guaranteed by setting the retransmission limit number. As described above, by reducing the number of retransmission restrictions for a high priority packet, the delay that propagates to higher layers is reduced. If a packet error remains even if the packet is retransmitted within the retransmission limit count, the determination is left to an upper layer such as an application as error processing.

  FIG. 5 is a diagram illustrating a configuration example of a frame. The frame generated by the frame generation unit 14 is transmitted as a radio frame at a timing determined according to the duplex method. As shown in FIG. 5, the frame has time and frequency dimensions, and the size thereof is determined according to the frequency band, the modulation method, and the like.

  In the frame configuration example shown in FIG. 5, the frame generation unit 14 receives four high priority packets read from the buffer 13-1 and eight low priority packets read from the buffer 13-2. The frame is stored so as to correspond to a predetermined time and frequency position.

  Since a packet with high priority read from the buffer 13-1 is subjected to error correction coding with high correction performance, a large amount of parity bits is generally added. On the other hand, packets with low priority read from the buffer 13-2 are subjected to error correction coding with low correction performance, and thus a small amount of parity bits is generally added.

  In FIG. 5, four high priority packets and eight low priority packets are stored in the frame. For each priority packet, a preset transmission rate is designated. Only high priority packets may be stored in the frame.

  Further, the frame generation unit 14 stores the packets read from the buffers 13-1 and 13-2 as they are in the frame, but stores the packets after interleaving such as frequency or / and time in the frame. You may make it do. In addition, when a certain reference adaptive modulation function (a function of changing the modulation scheme in accordance with the state of the wireless section) is used in the transmission unit 15 described later, the size of the wireless frame varies.

  Returning to FIG. 1, the transmission unit 15 receives a frame from the frame generation unit 14, performs a modulation process by a modulation unit (not shown), a frequency conversion process by a frequency conversion unit (not shown), a high frequency conversion process by a high frequency unit (not shown), and the like. As a radio frame, it is transmitted from a transmitting antenna (not shown) to a receiver 2-1 described later via a radio section.

  As described above, the radio frame is transmitted from the transmitter 1-1, and the radio frame includes the following two types of packets. The first packet is a packet having a high priority, a small number of retransmissions, and a large number of parity bits added. The second packet is a packet having a low priority, a large number of retransmissions, and a small amount of parity bits added.

  The receiving unit 16 inputs a wireless return frame by receiving a wireless return frame transmitted from the receiver 2-1 described later by a reception antenna (not shown) via a wireless section. And the receiving part 16 performs the reverse process of the transmission part 21 of the receiver 2-1 mentioned later. Specifically, the receiving unit 16 performs high frequency conversion processing by a high frequency unit (not shown), frequency conversion processing by a frequency conversion unit (not shown), demodulation processing by a demodulation unit (not shown), and the like, and outputs a return frame to the frame generation unit 14. .

  As described above, according to the transmitter 1-1 of the first embodiment, the distribution storage unit 10 receives a packet in which a priority order or the like is set, and distributes the packet based on the priority order. The error detection and error correction coding unit 12-1 performs error detection and error correction coding on a high priority packet using an error detection and error correction code having high correction performance, and performs error detection and error correction code. The converting unit 12-2 performs error detection and error correction coding on the low priority packet using an error detection and error correction code with low correction performance.

  The frame generation unit 14 stores a predetermined amount of high priority packets in a frame so that high priority packets are transmitted at a predetermined transmission rate, and the low priority packets remain in the remaining frame. A frame is generated by storing in the location. In addition, when the retransmission is performed, the frame generation unit 14 stores the packet to be retransmitted in the frame when the number of retransmissions is equal to or smaller than a preset retransmission limit number. The number of retransmission limits for packets with high priority is set in advance smaller than that for packets with low priority, and the number of retransmission restrictions for packets with low priority is set in advance with a larger number than for packets with high priority. Yes. Then, the frame is transmitted as a radio frame to a receiver 2-1 described later via a radio section.

  As a result, a packet with a high priority has a smaller number of retransmissions than a packet with a low priority, and when an error occurs in a wireless section, it is easier to be correctly decoded by error correction than a packet with a low priority. That is, a packet having a high priority can be reliably transmitted with a low delay and no failure. On the other hand, a packet with low priority is subjected to error correction with low correction performance, but the number of retransmissions increases.

  Therefore, high-priority content such as emergency relay video and audio is preferentially transmitted through a wireless section in which the frequency band is limited and the propagation environment is relatively unstable, and urgency is not required. However, in a transmission system that transmits a large-capacity file or the like that is desired to be transmitted as soon as possible, the entire packet can be realized in a simple configuration with balanced and efficient transmission according to priority.

[Receiver / Example 1]
Next, the receiver according to the first embodiment will be described. FIG. 6 is a block diagram illustrating a configuration example of the receiver according to the first embodiment. The receiver 2-1 includes a receiving unit 20, a transmitting unit 21, a packet extracting unit 22, a distribution storing unit 23, buffers 24-1 and 24-2, error correction decoding and error detecting units 25-1 and 25-2. The return frame generation unit 26 and the rearrangement unit 27 are provided. The receiver 2-1 is a device that receives video, audio, computer files, and the like from the transmitter 1-1 illustrated in FIG. 1 via a wireless section, and is provided in, for example, an FPU used by a broadcaster. The same applies to the receiver 2-2 of the second embodiment described later.

  The receiver 2-1 receives the radio frame transmitted from the transmitter 1-1 at the reception antenna via the radio section. The receiver 20 of the receiver 2-1 performs the reverse process of the transmitter 15 shown in FIG. Specifically, the receiving unit 20 inputs a radio frame received by the receiving antenna, performs high frequency conversion processing by a high frequency unit (not shown), frequency conversion processing by a frequency conversion unit (not shown), demodulation processing by a demodulation unit (not shown), and the like. The frame is output to the packet extraction unit 22.

  The packet extraction unit 22 receives a frame from the reception unit 20, extracts a packet from the frame, and outputs the packet to the packet extraction unit 22. The distribution storage unit 23 receives the packet from the packet extraction unit 22, performs the same processing as the distribution storage unit 10 shown in FIG. 1, distributes the packets according to the priority order, and distributes the distributed packets to the buffer 24- 1 and 24-2. Specifically, the distribution storage unit 23 extracts the priority order from the header of the packet, and distributes the high priority packet to the low priority packet based on the priority order, and the high priority packet to the buffer 24. -1 and the low priority packet is stored in the buffer 24-2.

  Note that the packet extraction unit 22 and the distribution storage unit 23, based on the position information set in advance for the frame input from the reception unit 20, from the position in the frame in which the high priority packet is stored, A packet having a high priority is extracted and stored in the buffer 24-1, and a packet having a low priority is extracted from a position in the frame where the packet having a low priority is stored and stored in the buffer 24-2. Also good. In the position information set in advance, information indicating where the high priority packet and the low priority packet are stored in the frame is defined, and the same information as the transmitter 1-1 is set. ing.

  The error correction decoding and error detection units 25-1 and 25-2 read packets from the corresponding buffers 24-1 and 24-2, perform different error correction decoding on the packets, and determine the presence or absence of packet errors. The error correction decoding and error detection units 25-1 and 25-2 send back an OK signal indicating that there is no packet error or an NG signal indicating that there is a packet error to the return frame generation unit 26. Further, when there is no packet error, the error correction decoding and error detection units 25-1 and 25-2 output the error correction decoded packet (packet consisting of a header and data) to the rearrangement unit 27.

  FIG. 7 is a diagram for explaining a processing example of the error correction decoding and error detection units 25-1 and 25-2. The error correction decoding and error detection unit 25-1 reads a packet having a high priority from the buffer 24-1 (step S701a), and the packet is sent to the error detection and error correction encoding unit 12-1 shown in FIG. The corresponding error correction decoding is performed using the error detection and error correction code having higher correction performance than the error correction decoding and error detection unit 25-2, and the presence / absence of a packet error is determined (step) S702a).

  When determining that there is no packet error, the error correction decoding and error detection unit 25-1 outputs the decoded packet to the rearrangement unit 27 (step S703a). In addition, the error correction decoding and error detection unit 25-1 generates an OK signal indicating that the decoding has been correctly performed on the packet, and outputs it to the return frame generation unit 26 (step S704a). As a result, a return frame including ACK is generated.

  On the other hand, if the error correction decoding and error detection unit 25-1 determines that there is a packet error, the error correction decoding and error detection unit 25-1 extracts the number of retransmissions from the header of the packet, and when the number of retransmissions is less than or equal to a preset retransmission limit number, An NG signal indicating that decoding has not been performed correctly is generated and sent back to the frame generation unit 26 (step S704a). As a result, a return frame including the retransmission request is generated. Further, the error correction decoding and error detection unit 25-1 performs predetermined error processing when the number of retransmissions exceeds a preset number of retransmission limits.

  The error correction decoding / error detection unit 25-2 reads out the low priority packet from the buffer 24-2 (step S701b), and the packet is sent to the error detection / error correction encoding unit 12-2 shown in FIG. The corresponding error correction decoding is performed using error detection and error correction codes having lower correction performance than the error correction decoding and error detection unit 25-1, and the presence / absence of a packet error is determined (step) S702b). If the error correction decoding / error detection unit 25-2 determines that there is no packet error, the error correction decoding / error detection unit 25-2 performs the same processing as the above-described step S703a and step S704a (step S703b, step S704b).

  On the other hand, if it is determined that there is a packet error, the error correction decoding and error detection unit 25-2 performs the same processing as in step S704a described above (step S704b), and the number of retransmissions exceeds the preset retransmission limit number. Predetermined error processing is performed.

  Here, as in the case of the transmitter 1-1, the number of retransmission restrictions for a packet with a high priority is set in advance smaller than the number of packets with a low priority, and the number of retransmission restrictions for a packet with a low priority is It is assumed that a larger number than the higher packet is set in advance, and the same number of times as the transmitter 1-1 is set.

  In the example illustrated in FIG. 7, the amount of parity bits of a packet with high priority is large, and the amount of parity bits of a packet with low priority is small. When such a packet is transmitted through a wireless section of the same environment, the number of retransmissions of a packet with a low priority is generally increased.

  Returning to FIG. 6, when the return frame generation unit 26 receives an OK signal or an NG signal from the error correction decoding and error detection units 25-1 and 25-2 and receives an OK signal, it responds to the OK signal. Generate an ACK for the packet. Further, when an NG signal is input, the return frame generation unit 26 generates a retransmission request for a packet corresponding to the NG signal. Then, the return frame generation unit 26 stores an ACK or retransmission request in the return frame for each packet, and outputs the return frame to the transmission unit 21.

  The transmission unit 21 receives a return frame from the return frame generation unit 26, performs modulation processing by a modulation unit (not shown), frequency conversion processing by a frequency conversion unit (not shown), high frequency conversion processing by a high frequency unit (not shown), and the like. As shown in FIG. 1, the signal is transmitted from a transmitting antenna (not shown) to the transmitter 1-1 via a wireless section.

  Thus, the wireless return frame is transmitted from the receiver 2-1, and the wireless return frame includes an ACK and a retransmission request.

  Although the wireless return frame including the ACK and the retransmission request is transmitted via the wireless section, any frame may be used as long as the packet corresponding to the ACK and the retransmission request can be identified.

  The rearrangement unit 27 receives the packets from the error correction decoding and error detection units 25-1 and 25-2, stores the packets in a buffer (not shown), extracts the packet order from the packet header, and changes the packet order. Based on this, the packets are rearranged, and the rearranged packets are output to a data restoration unit of a decoder (not shown in FIG. 6).

  For example, when selective retransmission (Selective-Repeat) is used as the ARQ scheme, the order of packets output from the error correction decoding and error detection units 25-1 and 25-2 may be switched. Therefore, the rearrangement unit 27 performs a process of returning the packet in which the order is changed to the original order. Thereby, the order of the packets is managed for each of the buffers 24-1 and 24-2, and the rearrangement unit 27 performs the order for the packets input from the error correction decoding and error detection units 25-1 and 25-2. When the correct packets are prepared, the packets are output in that order.

  6, a data restoration unit (a data restoration unit of a decoder provided outside the receiver 2-1) inputs a packet from the rearrangement unit 27 of the receiver 2-1, and receives data from the packet. The extracted data is combined to generate data such as video, audio, and computer file, and output as original video, audio, and computer file data.

  As described above, according to the receiver 2-1 of the first embodiment, the radio frame received from the transmitter 1-1 is subjected to reception processing to generate a frame, and the packet extraction unit 22 extracts the packet from the frame, The distribution storage unit 23 distributes packets according to the priority order.

  The error correction decoding and error detection unit 25-1 performs error correction decoding on a high priority packet using an error detection and error correction code having high correction performance, and determines the presence or absence of a packet error. The error correction decoding and error detection unit 25-2 performs error correction decoding on a low priority packet using an error detection and error correction code with low correction performance, and determines the presence or absence of a packet error. When it is determined that there is no packet error, the error correction decoding and error detection units 25-1 and 25-2 generate an OK signal. When it is determined that there is a packet error, the number of retransmissions is less than or equal to the retransmission limit number. , NG signal is generated. The number of retransmission limits for packets with high priority is set in advance smaller than that for packets with low priority, and the number of retransmission restrictions for packets with low priority is set in advance with a larger number than for packets with high priority. Yes.

  The return frame generation unit 26 generates an ACK for the packet corresponding to the OK signal, generates a retransmission request for the packet corresponding to the NG signal, and stores these in the return frame. Then, the return frame is transmitted as a wireless return frame to the transmitter 1-1 via the wireless section. The rearrangement unit 27 rearranges the decoded packets based on the packet order, and outputs the rearranged packets. Then, the packet is restored to the original video, audio, computer file, and other data by the data restoration unit of the decoder.

  As a result, a packet with a high priority has a smaller number of retransmissions than a packet with a low priority, and when an error occurs in a wireless section, it is easier to be correctly decoded by error correction than a packet with a low priority. That is, a packet having a high priority can be reliably transmitted with a low delay and no failure. On the other hand, a packet with low priority is subjected to error correction with low correction performance, and the number of retransmissions may increase, but more information can be stored in the wireless section.

  Therefore, high-priority content such as emergency relay video and audio is preferentially transmitted through a wireless section in which the frequency band is limited and the propagation environment is relatively unstable, and urgency is not required. However, in a transmission system that transmits a large-capacity file or the like that is desired to be transmitted as soon as possible, the entire packet can be realized in a simple configuration with balanced and efficient transmission according to priority.

[Example 2]
Next, Example 2 will be described. As described above, in the second embodiment, error correction is performed on all packets with a predetermined code, the number of retransmission processes is reduced to a small number for packets with high priority, and the header and data are set for packets with low priority. And a predetermined number of parity bits, and transmission is performed in units of division. The transmitter and receiver according to the second embodiment realize hybrid ARQ (HARQ) processing that combines FEC (error correction code) processing and ARQ (automatic retransmission request) processing.

[Transmitter / Example 2]
First, the transmitter according to the second embodiment will be described. FIG. 8 is a block diagram illustrating a configuration example of the transmitter according to the second embodiment. The transmitter 1-2 includes an error detection and error correction encoding unit 30, a distribution unit 31, a storage unit 32, a divided storage unit 33, buffers 34-1 and 34-2, a frame generation unit 35, a transmission unit 36, and A receiving unit 37 is provided.

  The transmitter 1-2 receives a packet from a packet generation unit of an encoder (not shown) provided outside as in the transmitter 1-1 illustrated in FIG.

  The error detection and error correction encoder 30 receives a packet from a packet generator of an encoder (not shown), and performs error detection and error correction encoding on the packet using a predetermined error detection and error correction code. Parity bits are generated, and parity bits are added to the packet header and data. Then, the error detection and error correction coding unit 30 outputs the packet after error detection and error correction coding (a packet including a header, data, and parity bits) to the distribution unit 31.

  As the error detection and error correction code, for example, an RS-CC concatenated code is used. The error detection and error correction coding unit 30 first performs Reed-Solomon coding for the RS-CC concatenated code, and further performs convolutional coding.

  As described above, the error detection and error correction code is a code that can perform error correction decoding on the decoding side and further perform error detection. For example, RS codes are used as error detection and error detection codes. Further, for example, a variable coding rate code is used as an error correction code in order to enable transmission in which a coding rate can be adjusted by dividing a parity bit in a division storage unit 33 described later. As one type of variable coding rate codes, there are RCPC (Rate Compatible Punctured Convolutional) codes, RCPT (Rate Compatible Punctured Turbo) codes, and the like.

  The allocating unit 31 receives the packet encoded from the error detection and error correction encoding unit 30, extracts the priority from the header of the packet, and based on the priority, the higher priority packet and the lower priority Sort to packet. Then, the distribution unit 31 outputs a packet with a high priority to the storage unit 32 and outputs a packet with a low priority to the division storage unit 33.

  The storage unit 32 receives a packet having a high priority from the distribution unit 31 and stores the input packet as it is in the buffer 34-1 without dividing the parity bits included in the packet.

  As a result, packets with high priority are stored in the buffer 34-1. Further, a packet having a high priority is transmitted from the subsequent frame generation unit 35 and transmission unit 36 without being thinned (punctured) or by a relatively small amount of puncture. That is, it is transmitted as a packet having a predetermined coding rate (fixed coding rate) determined by the error detection and error correction coding unit 30.

  The division storage unit 33 receives a low-priority packet from the distribution unit 31, divides the input packet into a header, data, and parity bits, and divides the parity bit into a predetermined number (divided parity bits). . For example, when the RCPC code is used in the error detection and error correction coding unit 30, the divided storage unit 33 sets a predetermined number of parity bits (divided parity bits) in a form along the puncture matrix used for the RCPC code. Divide into The divided storage unit 33 stores the header and data, and one or more divided parity bits (divided parity bits) in the buffer 34-2.

  As a result, the low-priority packet is stored in the buffer 34-2 in a divided state. Further, the low priority packet is transmitted by the subsequent frame generation unit 35 and transmission unit 36 in a thinned (punctured) state. That is, instead of being transmitted as a packet with a predetermined coding rate determined by the error detection and error correction coding unit 30, a plurality of coding rates and predetermined coding rates higher than the predetermined coding rate are set. Sent as a packet to realize. Also, every time a retransmission request (transmission request) is received from a receiver 2-2, which will be described later, the divided parity bits are transmitted, so that the coding rate is lowered for each retransmission request (transmission request).

  The storage unit 32 stores the parity bits of the high priority packet as it is in the buffer 34-1 without dividing it. The high-priority packets stored in the buffer 34-1 are packets having a predetermined coding rate determined by the error detection and error correction coding unit 30. On the other hand, the storage unit 32 has a division function similar to the division storage unit 33, and divides the header and data of the packet and the parity bit according to the propagation environment and use conditions of the radio section, and also converts the parity bit. You may make it divide | segment into predetermined number (the predetermined number of numbers smaller than the division | segmentation storage part 33). The storage unit 32 stores the header, data, and one or more divided parity bits in the buffer 34-1 in the same manner as the divided storage unit 33. The header, data, and the like of a packet with high priority stored in the buffer 34-1 are transmitted as a packet whose coding rate is adjusted according to the propagation environment and usage conditions in the radio section.

  FIG. 9 is a diagram illustrating a processing example of the distribution unit 31, the storage unit 32, and the divided storage unit 33. Based on the priority stored in the header of the packet, the allocating unit 31 distributes the packet with a higher priority and the packet with a lower priority (step S901). Note that the error correction code in FIG. 9 is an example of a systematic code (a code that can clearly distinguish an information sequence and a parity sequence before encoding: a Hamming code, a Reed-Solomon code, etc.). The same applies to a code in which the previous information sequence and the parity sequence cannot be clearly distinguished: a convolutional code that does not include a sequence that does not pass through the encoder.

  The storage unit 32 stores the high priority packet as it is in the buffer 34-1 (step S902). Thereby, the packet in which the parity bit is added to the header and data is stored in the buffer 34-1.

  The divided storage unit 33 divides the low priority packet into a header and data, and a predetermined number of parity bits (in the example of FIG. 9, the number of divided parity bits is 3), and the header and data are divided into three pieces. Are stored in the buffer 34-2 (step S903). Thereby, the buffer 34-1 stores the header and data (A) and the three parity bits (B, C, D).

  Returning to FIG. 8, the frame generation unit 35 reads out a packet having a high priority from the buffer 34-1 and reads the header and data of the packet with a low priority from the buffer 34-2 (divided parity bits at the time of retransmission). A predetermined amount of packets read from the buffer 34-1 are preferentially framed so that a constant transmission rate is ensured by reading and transmitting packets read from the buffer 34-1 at a predetermined transmission rate. To store. In addition, the frame generation unit 35 stores the header and data (parity bits divided at the time of retransmission) read from the buffer 34-2 in the remaining portion of the frame. Then, the frame generation unit 35 generates a frame and outputs it to the transmission unit 36.

  The frame generation unit 35 stores the high priority packet read from the buffer 34-1 at a predetermined position in the frame based on the preset position information, and the priority order read from the buffer 34-2. A low packet header and data (parity bits divided at the time of retransmission) may be stored in a predetermined position of the frame. The preset position information includes a packet having a high priority so that a packet having a high priority read from the buffer 34-1 is transmitted at a transmission rate of a predetermined speed to ensure a constant transmission rate. In addition, information indicating where in the frame the header and data of a packet with a low priority (divided parity bits at the time of retransmission) are stored is defined.

  The frame generation unit 35 receives the return frame from the reception unit 37, extracts the ACK and retransmission request (transmission request) included in the return frame, does not perform retransmission processing on the ACK, and retransmits the retransmission request (transmission request). Processing (transmission processing) is performed.

  The frame generation unit 35 stores a new number of retransmissions in the header for retransmission when the number of retransmissions is less than or equal to a preset number of retransmissions in the retransmission processing of a packet with high priority, and Store the corresponding packet in the frame. Further, the frame generation unit 35 performs predetermined error processing when the number of retransmissions exceeds a preset number of retransmission limits.

  In addition, in the retransmission processing (transmission processing) of the low priority packet, the frame generation unit 35 sets a new number of retransmissions when the number of retransmissions (number of transmissions) is equal to or less than a preset retransmission limit number (transmission limit number). (Transmission count) is stored in the header, and the divided parity bits are stored in the frame instead of the header and data transmitted first corresponding to the retransmission request (transmission request).

  In the example of FIG. 9, the buffer 34-2 stores a header, data (A), and divided parity bits (B, C, D). First, the frame generation unit 35 reads out the header and data (A) from the buffer 34-2 and stores them in the frame, and at the time of the first retransmission (transmission), reads out the parity bit (B) from the buffer 34-2 into the frame. Stores, reads the parity bit (C) from the buffer 34-2 at the next retransmission (transmission), stores it in the frame, and reads the parity bit (D) from the buffer 34-2 at the next retransmission (transmission). Store in frame.

  First, a decoding process is performed using only a header and data (A) by a receiver 2-2 described later. Actually, a small amount of parity bits are included in the header and data (A), and decoding is performed using these parity bits. Each time retransmission (transmission) is performed, the receiver 2-2 performs a decoding process using the header, data (A), and parity bit (B). Next, the header, data (A), and Decoding processing is performed using the parity bits (B, C), and then decoding processing is performed using the header, data (A), and parity bits (B, C, D).

  In the receiver 2-2, the decoding process is performed using only the header and data (A), and when there is no need for retransmission (transmission), the parity bit (B, C, D) of the packet is transmitted. Since it can be omitted, the parity transmission amount in the wireless section can be reduced. In addition, when the decoding process is performed with the header, data (A), and parity bit (B), and retransmission (transmission) is not required, transmission of the parity bit (C, D) of the packet may be omitted. If the decoding process is performed with the header, data (A), and parity bits (B, C) and there is no need for retransmission (transmission), transmission of the parity bit (D) of the packet is omitted. Therefore, the amount of parity transmission in the wireless section can be reduced.

  Here, as in the first embodiment, the retransmission limit number is preset to a smaller number for a packet with a higher priority, and a larger number (a number corresponding to the number of divided parity bits) for a packet with a lower priority. It is assumed that it is set in advance. The retransmission limit number indicates the maximum number of times that can be retransmitted by the transmitter 1-2 when the later-described receiver 2-2 cannot correctly decode the packet. Similar to the retransmission limit count, the transmission limit count indicates the maximum number of times that transmission is possible. 0 may be set as the retransmission limit count for a packet with high priority.

  The transmission unit 36 and the reception unit 37 are the same as the transmission unit 15 and the reception unit 16 shown in FIG.

  In this way, a radio frame is transmitted from the transmitter 1-2, and the radio frame includes the following first packet and divided data obtained by dividing the second packet. The first packet has a high priority, is composed of a header, data, and parity bits, and has a small number of retransmissions. The divided data includes a header and data obtained by dividing a packet having a low priority, and a parity bit divided into a predetermined number, and the number of retransmissions is large. The parity bit divided into a predetermined number is a divided parity bit obtained by dividing a parity bit generated by error correction coding into a predetermined number.

  As described above, according to the transmitter 1-2 of the second embodiment, the error detection and error correction coding unit 30 inputs a packet in which priority order is set, and performs error detection and error using a predetermined code. Correction encoding is performed, and the distribution unit 31 distributes the encoded packets based on the priority order. The division storage unit 33 divides a low priority packet into a header and data and a predetermined number of parity bits.

  The frame generation unit 35 stores a predetermined amount of high priority packets in a frame so that high priority packets are transmitted at a transmission rate of a predetermined speed. A frame is generated by storing only the header and data in the remaining part of the frame. Further, the frame generator 35 stores the first parity bit of the predetermined number of divided parity bits in the frame, instead of the header and data, at the time of retransmission (transmission) for the low priority packet. At the next retransmission (transmission), the second parity bit is stored in the frame. That is, for each retransmission (transmission), one parity bit among a predetermined number of divided parity bits is stored in the frame. Then, the frame is transmitted as a radio frame to a receiver 2-2 described later via a radio section.

  As a result, a packet having a higher priority has a smaller number of retransmissions than a packet having a lower priority. In addition, since packets with high priority are added with more parity bits in one transmission than packets with low priority, when an error occurs in a wireless section, packets with low priority are compared with packets with low priority. Also, it becomes easy to correctly decode by error correction. That is, a packet having a high priority can be reliably transmitted with a low delay and no failure.

  In addition, in the low priority packet, only the header and data are transmitted first, and the parity bit is thinned out. Therefore, when the propagation environment in the radio section is good, the overhead due to the parity bit in the radio frame can be reduced. it can. On the other hand, when the propagation environment in the radio section deteriorates and an error occurs, a part of the parity bit is additionally transmitted to reduce the coding rate. Although a delay is caused by the transmission of the parity bit, a decoding process using a minimum parity bit according to the environment can be realized. In the same propagation environment, a packet with a low priority has a higher number of retransmissions than a packet with a high priority.

  Therefore, high-priority content such as emergency relay video and audio is preferentially transmitted through a wireless section in which the frequency band is limited and the propagation environment is relatively unstable, and urgency is not required. However, in a transmission system that transmits a large-capacity file or the like that is desired to be transmitted as soon as possible, the entire packet can be realized in a simple configuration with balanced and efficient transmission according to priority.

  Further, in the transmitter 1-2, the same encoder can be used regardless of the difference in processing between the high priority packet and the low priority packet. In the receiver 2-2 described later, the same encoder is used. The same decoder corresponding to the encoder can be used. As a result, labor saving in hardware design can be expected.

[Receiver / Example 2]
Next, a receiver according to the second embodiment will be described. FIG. 10 is a block diagram illustrating a configuration example of a receiver according to the second embodiment. The receiver 2-2 includes a receiving unit 40, a transmitting unit 41, a packet extracting unit 42, a distribution storing unit 43, buffers 44-1, 44-2, error correction decoding and error detecting units 45-1, 45-2. A return frame generation unit 46 and a rearrangement unit 47 are provided.

  The receiver 2-2 receives the radio frame transmitted from the transmitter 1-2 by the reception antenna via the radio section. The receiver 40 of the receiver 2-2 performs the reverse process of the transmitter 36 shown in FIG. The receiving unit 40 is the same as the receiving unit 20 shown in FIG.

  The packet extraction unit 42 receives a frame from the reception unit 40, extracts a packet with a high priority from the frame, and extracts a header and data of a packet with a low priority, and a divided parity bit of a packet with a low priority. Then, the packet extraction unit 42 outputs the high priority packet, the header and data of the low priority packet, and the divided parity bits of the low priority packet to the distribution storage unit 43.

  The distribution storage unit 43 receives a packet or the like from the packet extraction unit 42, distributes the packet or the like according to the priority order, and stores the distributed packet or the like in the buffers 44-1 and 44-2. Specifically, when the packet is input, the distribution storage unit 43 extracts the priority from the header of the packet, confirms that the packet is a high priority packet based on the priority, Is stored in the buffer 44-1. As a result, a packet having a high priority is stored in the buffer 44-1 with a parity bit added to the header and data.

  The distribution storage unit 43, when the header and data are input, extracts the priority from the header, and based on the priority, confirms that the header and data are the header and data in the low priority packet, The header and data are stored in the buffer 44-2. Further, when a parity bit is input, the distribution storage unit 43 stores the parity bit in the buffer 44-2 on the assumption that the parity bit is a part of the parity bit in the packet having a low priority. As a result, the header and data of the low priority packet are stored in the buffer 44-2, and the divided parity bits of the low priority packet are stored for each retransmission (transmission).

  Note that the packet extraction unit 42 and the distribution storage unit 43, based on the position information set in advance for the frame input from the reception unit 40, from the position in the frame in which the high priority packet is stored, A packet having a high priority is taken out and stored in the buffer 44-1, and a header and data of a packet having a low priority or a priority from a position in a frame in which the header and data of the packet having a low priority are stored. Alternatively, the divided parity bits of the low packet may be extracted and stored in the buffer 44-2. The position information set in advance defines information indicating in which position a packet having a high priority, a header and data of a packet having a low priority are stored in the frame, and the transmitter 1-2. The same information is set.

  The error correction decoding and error detection unit 45-1 is an error correction decoding and error detection process corresponding to the error detection and error correction encoding unit 30 shown in FIG. The same processing as that of the detection unit 25-1 is performed. Specifically, the error correction decoding and error detection unit 45-1 reads a packet having a high priority from the buffer 44-1, performs error correction decoding on the packet, determines whether there is an error in the packet, If there is no error, an OK signal is generated and sent back to the frame generation unit 46, and the decoded packet (packet consisting of a header and data) is output to the rearrangement unit 47.

  When there is a packet error, the error correction decoding and error detection unit 45-1 generates an NG signal and outputs it to the return frame generation unit 46 when the number of retransmissions extracted from the header is less than or equal to a preset retransmission limit number. To do. Further, the error correction decoding and error detection unit 45-2 performs predetermined error processing when the number of retransmissions exceeds the retransmission limit number.

  For example, the error correction decoding and error detection unit 45-1 is subjected to Reed-Solomon encoding and convolutional encoding as RS-CC concatenated codes by the error detection and error correction encoding unit 30 illustrated in FIG. In this case, Viterbi decoding and Reed-Solomon code decoding are performed.

  The error correction decoding and error detection unit 45-2 reads out the header and data of the low priority packet or the divided parity bits of the low priority packet from the buffer 44-2. Then, when the header and data are read, the error correction decoding and error detection unit 45-2 performs error correction decoding on the header and data, and determines whether there is an error in the packet.

  When the parity bit is read, the error correction decoding and error detection unit 45-2 combines the currently read parity bit with the header and data that have already been read, and generates combined data. Further, when the combined data already exists, the error correction decoding and error detection unit 45-2 combines the parity bit read this time with the combined data to generate new combined data. Then, the error correction decoding and error detection unit 45-2 performs error correction decoding on the combined data and determines whether there is an error in the packet.

  When it is determined that there is no packet error, the error correction decoding and error detection unit 45-2 generates an OK signal, outputs it to the return frame generation unit 46, and outputs the error correction decoded packet (packet consisting of header and data). The data is output to the sorting unit 47. On the other hand, when the error correction decoding and error detection unit 45-2 determines that there is a packet error, when the number of retransmissions extracted from the header is less than or equal to a preset retransmission limit number, an NG signal is generated and a return frame is transmitted. The data is output to the generation unit 46. Further, the error correction decoding and error detection unit 45-2 performs predetermined error processing when the number of retransmissions exceeds the retransmission limit number.

  FIG. 11 is a diagram for explaining a processing example of the distribution storage unit 43, error correction decoding and error detection units 45-1, 45-2. The distribution storage unit 43 receives and distributes packets and the like from the packet extraction unit 22, stores packets with high priority in the buffer 44-1, and buffers headers, data, and parity bits of packets with low priority. 44-2 (step S1101).

  Assume that in the transmitter 1-2, a packet with low priority is divided into a header and data, and a predetermined number of parity bits (3 in the example of FIG. 11 and corresponding to FIG. 9). . The distribution storage unit 43 stores the header and data (A) in the buffer 44-2 for the first time, and stores the parity bit (B) in the buffer 44-2 for the second time (during the first retransmission (transmission)). The parity bit (C) is stored in the buffer 44-2 for the third time (during the next retransmission (transmission)), and the parity bit (D) is stored in the buffer 44-2 for the fourth time (during the next retransmission (transmission)). Store.

  Information for identifying each of the header, data (A), and parity bits (B, C, D) is stored in the header of the frame, and the packet extraction unit 42 identifies the information when extracting these. .

  The error correction decoding and error detection unit 45-1 reads the packet from the buffer 44-1 (step S1102), performs error correction decoding on the packet, determines whether there is an error in the packet, and outputs an OK signal or an NG signal. Generate (step S1103). When there is no packet error, the return frame generation unit 46 generates a return frame including ACK based on the OK signal. When there is a packet error, based on the NG signal (NG signal for retransmitting the packet). A frame including a retransmission request is generated. Then, it is transmitted to the transmitter 1-2 as a wireless return frame.

  The error correction decoding and error detection unit 45-2 first reads the header and data (A) from the buffer 44-2, and sets a parity bit (parity) in which, for example, bit likelihood 0 is set in the header and data (A). Parity bits set with a bit likelihood of 0 are combined with regions corresponding to bits B, C, and D to generate combined data (step S1104). Then, the error correction decoding and error detection unit 45-2 performs error correction decoding on the combined data and determines whether there is an error in the packet (step S1105). Actually, a small amount of parity bits are included in the header and data (A), and decoding is performed using these parity bits.

  When there is no packet error, the return frame generation unit 46 generates a return frame including ACK based on the OK signal. When there is a packet error, the NG signal (for transmitting the parity bit (B) of the packet) Based on the (NG signal), a frame including a retransmission request (transmission request for transmitting the parity bit (B) of the packet) is generated. Then, it is transmitted to the transmitter 1-2 as a wireless return frame. In the case of a retransmission request (transmission request), a parity bit (B) is transmitted from the transmitter 1-2.

  The error correction decoding and error detection unit 45-2 reads the parity bit (B) from the buffer 44-2 for the second time (during the second transmission of the packet), and adds parity to the already read header and data (A). The bit (B) is combined, and further, for example, a parity bit in which bit likelihood 0 is set (a parity bit in which bit likelihood 0 is set in an area corresponding to the parity bits C and D) is combined to generate combined data (Step S1104). Then, the error correction decoding and error detection unit 45-2 performs error correction decoding on the combined data and determines whether there is an error in the packet (step S1105).

  The processing when there is no packet error and when there is a packet error is as described above, and in the case of a retransmission request (transmission request for transmitting the parity bit (C) of the packet), from the transmitter 1-2. A parity bit (C) is transmitted.

  The error correction decoding and error detection unit 45-2 reads the parity bit (C) from the buffer 44-2 for the third time (during the third transmission of the packet), and generates already generated combined data (header and data (A ) Is combined with the parity bit (C) and the parity bit (C) is set, for example, and the bit likelihood is set to 0 (bit likelihood 0 is set in the region corresponding to the parity bit D). Parity data) is combined to generate combined data (step S1104). Then, the error correction decoding and error detection unit 45-2 performs error correction decoding on the combined data and determines whether there is an error in the packet (step S1105).

  The processing when there is no packet error and when there is a packet error is as described above, and in the case of a retransmission request (transmission request for transmitting the parity bit (D) of the packet), from the transmitter 1-2. A parity bit (D) is transmitted.

  The error correction decoding and error detection unit 45-2 reads the parity bit (D) from the buffer 44-2 for the fourth time (at the time of the fourth transmission of the packet), and generates already generated combined data (header and data (A ) And the parity bit (D) are combined with the combined data obtained by combining the parity bits (B, C) with each other) to generate combined data (step S1104). Then, the error correction decoding and error detection unit 45-2 performs error correction decoding on the combined data and determines whether there is an error in the packet (step S1105). When there is a packet error, predetermined error processing is performed.

  As described above, the error correction decoding and error detection unit 45-2 generates combined data according to the number of transmissions, and performs decoding processing. When the combined data is generated, for example, a process of adding the likelihood in bit units is performed according to the puncture matrix of the RCPC code.

  In FIG. 11, the number of transmissions has been described as four, but the number of transmissions may be five or more or three or less. For example, when the number of transmissions is 5 or more, the same header and data (A), parity bits (B, C, D) already transmitted from the transmitter 1-2, or other sorts are generated. A transmitted bit string (for example, a part of A) may be retransmitted. In this case, the error correction decoding and error detection unit 45-2 reads the parity bit (D) from the buffer 44-2 for the fourth time, performs processing, and determines that there is a packet error, for example, header and data ( An NG signal for retransmitting A) is generated. In addition, the error correction decoding and error detection unit 45-2 reads the retransmitted header and data (A) from the buffer 44-2 for the fifth time, performs processing, and determines that there is a packet error. An NG signal for retransmitting the bit (B) is generated.

  Further, the packet extraction unit 42, the distribution storage unit 43, the buffer 44-1, and the error correction decoding / error detection unit 45-1 use the coding rate of the high priority packet as a reference for the high priority packet. Processing is performed. On the other hand, when the storage unit 32 of the transmitter 1-2 shown in FIG. 8 also has a division function, and the packet is divided into a header and data and a predetermined number of parity bits, the packet extraction unit of the receiver 2-2 42, the distribution storage unit 43, the buffer 44-1, and the error correction decoding and error detection unit 45-1 are arranged for the low priority packet for each of the header and data of the high priority packet and the predetermined number of parity bits. The same processing as the header and data may be performed. In this case, the error correction decoding and error detection units 45-1 and 45-2 can have the same configuration, and the hardware design can be simplified. Note that the predetermined number of divided parity bits in the high priority packet is smaller than the predetermined number of low priority packets.

  Similarly to the transmitter 1-2, the number of retransmission restrictions for a packet with a high priority is set in advance to be smaller than that for a packet with a low priority, and the number of retransmission restrictions for a packet with a low priority (transmission restriction number). It is assumed that a larger number (a number corresponding to the number of divided parity bits) than a packet having a higher priority is set in advance. The retransmission limit number indicates the maximum number of times that can be retransmitted by the transmitter 1-2 when the later-described receiver 2-2 cannot correctly decode the packet. Similar to the retransmission limit count, the transmission limit count indicates the maximum number of times that transmission is possible. 0 may be set as the retransmission limit count for a packet with high priority.

  Returning to FIG. 10, the return frame generation unit 46 receives the OK signal and the NG signal from the error correction decoding and error detection unit 45-1, and performs the same processing as the return frame generation unit 26 shown in FIG. Specifically, when the return frame generation unit 46 receives an OK signal from the error correction decoding and error detection unit 45-1, the return frame generation unit 46 generates an ACK of the packet corresponding to the OK signal, and the error correction decoding and error detection unit When an NG signal is input from 45-1, a packet retransmission request corresponding to the NG signal is generated.

  The return frame generation unit 46 receives the OK signal and the NG signal from the error correction decoding and error detection unit 45-2, and generates an ACK and a transmission request. Specifically, when an OK signal is input, the return frame generation unit 46 generates a packet header and data corresponding to the OK signal, or an ACK of the parity bit. Further, when an NG signal is input, the return frame generation unit 46 generates a transmission request for another (next) parity bit in the packet corresponding to the NG signal. Then, the return frame generation unit 46 stores the ACK, retransmission request, or transmission request in the return frame for each packet, and outputs the return frame to the transmission unit 41.

  The rearrangement unit 47 is the same as the rearrangement unit 27 shown in FIG. In addition, a data restoration unit (a data restoration unit of a decoder provided outside the receiver 2-2) not shown in FIG. 10 inputs a packet from the rearrangement unit 47 of the receiver 2-2, and starts from the packet. Data is extracted, and the extracted data is combined to generate data such as video, audio, and computer file, and output as original video, audio, and computer file data.

  As described above, according to the receiver 2-2 of the second embodiment, the radio frame received from the transmitter 1-2 is subjected to reception processing to generate a frame, and the packet extraction unit 42 generates a packet, a header, and a frame from the frame. Data and parity data are extracted, and the distribution storage unit 43 distributes packets and the like. The error correction decoding and error detection unit 45-1 performs error correction decoding corresponding to the error detection and error correction coding unit 30 shown in FIG. 8 on the high priority packet, and determines the presence or absence of a packet error. . When the error correction decoding and error detection unit 45-1 determines that there is no packet error, the error correction decoding and error detection unit 45-1 generates an OK signal. When it is determined that there is a packet error, the error correction decoding and error detection unit 45-1 is the same. An NG signal for retransmitting the packet is generated.

  The error correction decoding and error detection unit 45-2 performs error detection and error correction coding unit shown in FIG. 8 on the header and data of the low priority packet or the combined data in which the parity bit is combined with the header and data. Error correction decoding corresponding to 30 is performed to determine whether there is an error in the packet. If it is determined that there is no packet error, the error correction decoding and error detection unit 45-2 generates an OK signal. If it is determined that there is a packet error, the error correction decoding and error detection unit 45-2 An NG signal for transmitting a bit is generated.

  The return frame generation unit 46 generates an ACK of the packet corresponding to the OK signal for the high priority packet, generates a retransmission request for the packet corresponding to the NG signal, and corresponds to the OK signal for the low priority packet. A packet header and data, or an ACK of the parity bit is generated, a transmission request for other parity bits in the packet corresponding to the NG signal is generated, and these are sent back and stored in the return frame. Then, the return frame is transmitted as a wireless return frame to the transmitter 1-2 via the wireless section. In addition, the rearrangement unit 47 rearranges the decoded packets (packets composed of the header and data) based on the packet order, and outputs the rearranged packets. Then, the packet is restored to the original video, audio, computer file, and other data by the data restoration unit of the decoder.

  As a result, a packet having a higher priority has a smaller number of retransmissions than a packet having a lower priority. In addition, since packets with high priority are added with more parity bits in one transmission than packets with low priority, when an error occurs in a wireless section, packets with low priority are compared with packets with low priority. Also, it becomes easy to correctly decode by error correction. That is, a packet having a high priority can be reliably transmitted with a low delay and no failure.

  In addition, in the low priority packet, only the header and data are transmitted first, and the parity bit is thinned out. Therefore, when the propagation environment in the radio section is good, the overhead due to the parity bit in the radio frame can be reduced. it can. On the other hand, when the propagation environment in the radio section deteriorates and an error occurs, a part of the parity bit is additionally transmitted to reduce the coding rate. Although a delay is caused by the transmission of the parity bit, a decoding process using a minimum parity bit according to the environment can be realized. In the same propagation environment, a packet with a low priority has a higher number of retransmissions than a packet with a high priority.

  Therefore, high-priority content such as emergency relay video and audio is preferentially transmitted through a wireless section in which the frequency band is limited and the propagation environment is relatively unstable, and urgency is not required. However, in a transmission system that transmits a large-capacity file or the like that is desired to be transmitted as soon as possible, the entire packet can be realized in a simple configuration with balanced and efficient transmission according to priority.

  Further, in the receiver 2-2, the same decoder corresponding to the same encoder in the transmitter 1-2 can be used regardless of the difference in processing between the high priority packet and the low priority packet. it can. As a result, labor saving in hardware design can be expected.

  The present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the first and second embodiments, and various modifications can be made without departing from the technical idea thereof. For example, the first embodiment targets a transmission system including a transmitter 1-1 and a receiver 2-1, and the second embodiment targets a transmission system including a transmitter 1-2 and a receiver 2-2. As described above, the present invention is a transceiver having the function of the transmitter 1-1 and the function of the receiver 2-1, and the transmission / reception having the function of the transmitter 1-2 and the function of the receiver 2-2. The machine also has application.

  Specifically, the transceiver corresponding to the first embodiment includes an allocation storage unit 10, buffers 11-1 and 11-2, error detection and error correction encoding units 12-1 and 12-2, and a buffer 13-1. 13-2, a transmission processing unit including a frame generation unit 14, a transmission unit 15 and a reception unit 16, a reception unit 20, a transmission unit 21, a packet extraction unit 22, a distribution storage unit 23, and buffers 24-1 and 24. -2, an error correction decoding and error detection unit 25-1, 25-2, a reception processing unit including a return frame generation unit 26 and a rearrangement unit 27. For example, a transmission system is configured by two transceivers corresponding to the first embodiment.

  The transceiver corresponding to the second embodiment includes an error detection and error correction encoding unit 30, a distribution unit 31, a storage unit 32, a divided storage unit 33, buffers 34-1 and 34-2, a frame generation unit 35, Transmission processing unit including transmission unit 36 and reception unit 37, reception unit 40, transmission unit 41, packet extraction unit 42, distribution storage unit 43, buffers 44-1, 44-2, error correction decoding and error detection unit 45-1, 45-2, a reception processing unit including a return frame generation unit 46 and a rearrangement unit 47. For example, a transmission system is configured by two transceivers corresponding to the second embodiment.

  In the first and second embodiments, the retransmission control requires a duplex method for performing bidirectional communication. However, the present invention is not limited to this, and time division duplex and frequency division duplex are not limited thereto. Any method may be used, and the frequency band is not questioned.

  In the first and second embodiments, the transmitters 1-1 and 1-2 transmit radio frames to the receivers 2-1 and 2-2 through the radio section, and the receivers 2-1 and 2-2 are transmitted. -2 transmits the return radio frame to the transmitters 1-1 and 1-2 via the radio section. The present invention is applicable not only to wireless communication paths but also to wired communication paths. That is, the transmitters 1-1 and 1-2 transmit the frame to the receivers 2-1 and 2-2 through the wired section, and the receivers 2-1 and 2-2 transmit the return frame to the wired unit. You may transmit to the transmitters 1-1 and 1-2 via a section.

  Further, the transmitters 1-1 and 1-2 transmit the radio frame to the receivers 2-1 and 2-2 via the radio section, and the receivers 2-1 and 2-2 transmit the return frame, You may make it transmit to the transmitter 1-1 and 1-2 via a wired area. Further, the transmitters 1-1 and 1-2 transmit the frame to the receivers 2-1 and 2-2 via the wired section, and the receivers 2-1 and 2-2 transmit the wireless return frame, You may make it transmit to the transmitter 1-1 and 1-2 via a radio area.

  Further, in the second embodiment, in FIGS. 9 and 11, the number of divisions of the parity bits added to the header and the data is described as 3, but this is an example, and the number of divisions of the parity bits is 1 or more. That's fine. When the number of parity bit divisions is 1, the parity bits are not divided. That is, in FIG. 9, a packet including a header, data, and parity bits is divided into a header, data, and one parity bit.

  In the first and second embodiments, FEC (error correction code) processing and ARQ (automatic retransmission request) processing are performed by the transmitters 1-1 and 1-2 and the receivers 2-1 and 2-2. The combined hybrid ARQ (HARQ) processing is realized, but this is an example, and other processing may be used.

  In the first and second embodiments, the number of retransmission limits for defining the number of retransmissions of packets and the like is set in advance in the transmitters 1-1 and 1-2 and the receivers 2-1 and 2-2. Explained as a thing. On the other hand, the transmitters 1-1 and 1-2 include a retransmission limit number setting unit that sets a retransmission limit number and stores it in a packet header. The receivers 2-1 and 2-2 include packet headers. A retransmission limit number extraction unit that extracts the retransmission limit number from the above may be provided.

  The retransmission limit count setting units of the transmitters 1-1 and 1-2 set a smaller number of retransmission limits for packets with higher priority than packets with lower priority, and store the retransmission limit count in the header thereof. For a low priority packet, a larger number of retransmission limit times than for a higher priority packet are set, and the retransmission limit number is stored in the header. In addition, the retransmission limit number extraction unit of the receivers 2-1 and 2-2 extracts the number of retransmission limit times smaller than that of the low priority packet from the header of the high priority packet, and extracts the low priority packet. From the header, the number of retransmission limit times larger than that of the high priority packet is extracted. In this case, the encoder may include a retransmission limit number setting unit.

1 Transmitter 2 Receiver 10, 23, 43 Distribution storage unit 11, 13, 24, 34, 44 Buffer 12, 30 Error detection and error correction encoding unit 14, 35 Frame generation unit 15, 21, 36, 41 Transmission Units 16, 20, 37, 40 receiving unit 22, 42 packet extracting unit 25, 45 error correction decoding and error detecting unit 26, 46 return frame generating unit 27, 47 rearrangement unit 31 distribution unit 32 storage unit 33 division storage unit

Claims (6)

In a transmitter that inputs a packet including a header and data in which priority is stored, stores the packet in error detection and error correction encoding, and transmits the frame to a receiver.
A distribution unit that distributes the packets according to the priority order;
For packets distributed by the allocating unit, the higher the priority, the higher the correction performance code is used, and the lower the priority, the lower the correction performance code, error detection and error correction coding are performed. An error detection and error correction encoding unit that generates a parity bit and generates a packet including the header and data and the parity bit;
Among the packets error-detected and error-corrected encoded by the error detection and error-correction encoder, the error detection and error correction are performed such that a predetermined packet having a higher priority is transmitted at a predetermined transmission rate. Storing the encoded packet in the frame;
The higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number of retransmission limit counts in accordance with the retransmission request from the receiver in accordance with the retransmission request. A frame generation unit for storing the packet in the frame and generating the frame;
A transmitter characterized by comprising: In a transmitter that inputs a packet including a header and data in which priority is stored, stores the packet in error detection and error correction encoding, and transmits the frame to a receiver.
An error detection and error correction encoding unit that performs error detection and error correction encoding on the packet using a predetermined code, generates a parity bit, and generates a packet including the header and data and the parity bit; ,
A distribution unit that distributes packets that have been subjected to error detection and error correction coding by the error detection and error correction coding unit according to the priority order;
Dividing a predetermined packet having a low priority among the packets distributed by the distribution unit into the header and data and the parity bit, and dividing the parity bit into a predetermined number of divided parity bits And
Among the packets distributed by the allocating unit, the predetermined packet with the higher priority is stored in the frame so that the predetermined packet with the higher priority is transmitted at a predetermined transmission rate. For the predetermined packet having a low rank, the header and data divided by the dividing unit, or the divided parity bits are stored in the frame, and
The higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number of retransmission limit counts in accordance with the retransmission request from the receiver in accordance with the retransmission request. A packet generation unit that stores the packet, the header and data, or the divided parity bit in the frame, and generates the frame;
For the predetermined packet with low priority, first, the header and data are stored in the frame and transmitted, and at each retransmission, one of the predetermined number of divided parity bits is set as the divided parity bit. A transmitter characterized in that it is stored in a frame and transmitted. In a receiver for receiving a frame transmitted from the transmitter of claim 1, extracting a packet from the frame, performing error correction decoding, determining a packet error and transmitting a return frame to the transmitter;
A packet extraction and distribution unit that extracts packets from the frame and distributes packets according to priority;
For packets distributed by the packet extraction and distribution unit, the higher the priority, the higher the correction performance code is used, and the lower the priority is, the lower the correction performance code is used for error correction decoding, If it is determined whether there is a packet error and it is determined that there is no packet error, an error correction decoding and error detection unit that outputs a packet including a header and data after decoding;
When it is determined by the error correction decoding and error detection unit that there is a packet error, the number of retransmission limit times is set such that the higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number. A return frame generation unit for generating a return frame including a retransmission request for retransmitting the packet determined to have the packet error,
A receiver comprising: A frame transmitted from the transmitter of claim 2 is received, a packet, a header and data, and a divided parity bit are extracted from the frame, error correction decoding is performed, a packet error is determined, and a return frame is transmitted to the transmitter. Receiver
A packet having a high priority is extracted from the frame, and a header and data of a packet having a low priority or a parity bit of a packet having a low priority is divided into a predetermined number, and the priority parity packet is extracted. A packet extraction and distribution unit that distributes a high packet to a header and data of the low priority packet or a divided parity bit of the low priority packet;
If the packet with high priority distributed by the packet extraction and distribution unit is subjected to error correction decoding with a predetermined code to determine the presence or absence of a packet error, A first error correction decoding and error detection unit for outputting a packet comprising a later header and data;
When the header and data of the low priority packet are sorted by the packet fetching and sorting unit, error correction decoding is performed with the predetermined code using the header and data to determine the presence or absence of a packet error When it is determined that there is no packet error, a packet composed of the header and data after decoding is output,
When the divided parity bit of the low priority packet is distributed by the packet extraction and distribution unit, the same packet header and data as the low priority packet, and the divided parity bit distributed this time are used. Or, using the header and data of the same packet as the low priority packet, the previously allocated divided parity bit, and the divided parity bit allocated this time, error correction decoding is performed with the predetermined code. Performing a second error correction decoding and error detection unit for outputting a packet composed of a header and data after decoding, if it is determined that there is no packet error;
When the first error correction decoding and error detection unit determines that there is a packet error, the retransmission limit is set to a smaller number for the higher priority packet and to a larger number for the lower priority packet. A return frame including a retransmission request for retransmitting the packet determined to have the packet error within the range of the number of times,
If the second error correction decoding and error detection unit determines that there is a packet error, the divided parity bits that have not been transmitted yet in the packet determined to have the packet error within the range of the retransmission limit number A return frame generation unit that generates a return frame including a retransmission request for transmitting
A receiver comprising: A packet consisting of a header and data in which priority is stored is input, the packet is subjected to error detection and error correction coding, stored in a frame, a transmission processing unit that transmits the frame, a frame is received, In a transceiver having a reception processing unit that takes out a packet, performs error correction decoding, determines a packet error, and transmits a return frame,
The transmission processing unit
A distribution unit that distributes the packets according to the priority order;
For packets distributed by the allocating unit, the higher the priority, the higher the correction performance code is used, and the lower the priority, the lower the correction performance code, error detection and error correction coding are performed. An error detection and error correction encoding unit that generates a parity bit and generates a packet including the header and data and the parity bit;
Among the packets error-detected and error-corrected encoded by the error detection and error-correction encoder, the error detection and error correction are performed such that a predetermined packet having a higher priority is transmitted at a predetermined transmission rate. Storing the encoded packet in the frame;
The higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number of retransmission limit times in accordance with a retransmission request from another transceiver according to the retransmission request. A frame generation unit that stores the packet in the frame and generates the frame;
The reception processing unit
A packet extraction and distribution unit that extracts packets from the frame and distributes packets according to priority;
For packets distributed by the packet extraction and distribution unit, the higher the priority, the higher the correction performance code is used, and the lower the priority is, the lower the correction performance code is used for error correction decoding, If it is determined whether there is a packet error and it is determined that there is no packet error, an error correction decoding and error detection unit that outputs a packet including a header and data after decoding;
When it is determined by the error correction decoding and error detection unit that there is a packet error, the number of retransmission limit times is set such that the higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number. A return frame generation unit for generating a return frame including a retransmission request for retransmitting the packet determined to have the packet error,
A transmitter / receiver characterized by comprising: A packet consisting of a header and data in which priority is stored is input, the packet is subjected to error detection and error correction coding, stored in a frame, a transmission processing unit that transmits the frame, a frame is received, In a transceiver having a reception processing unit that takes out a packet, a header and data, and a divided parity bit, performs error correction decoding, determines a packet error, and transmits a return frame,
The transmission processing unit
An error detection and error correction encoding unit that performs error detection and error correction encoding on the packet using a predetermined code, generates a parity bit, and generates a packet including the header and data and the parity bit; ,
A distribution unit that distributes packets that have been subjected to error detection and error correction coding by the error detection and error correction coding unit according to the priority order;
Dividing a predetermined packet having a low priority among the packets distributed by the distribution unit into the header and data and the parity bit, and dividing the parity bit into a predetermined number of divided parity bits And
Among the packets distributed by the allocating unit, the predetermined packet with the higher priority is stored in the frame so that the predetermined packet with the higher priority is transmitted at a predetermined transmission rate. For the predetermined packet having a low rank, the header and data divided by the dividing unit, or the divided parity bits are stored in the frame, and
The higher priority packet is set to a smaller number, and the lower priority packet is set to a larger number of retransmission limit times in accordance with a retransmission request from another transceiver according to the retransmission request. A frame generation unit that stores the packet, the header and data, or the divided parity bits in the frame, and generates the frame; and
For the predetermined packet with low priority, first, the header and data are stored in the frame and transmitted, and at the time of retransmission, the first divided parity bit of the predetermined number of divided parity bits is transmitted to the frame. Store and transmit, and at the next retransmission, store and transmit the second divided parity bit of the predetermined number of divided parity bits in the frame, and transmit another divided parity bit to the frame at the time of further retransmission Store and send,
The reception processing unit
A packet having a high priority is extracted from the frame, and a header and data of a packet having a low priority or a parity bit of a packet having a low priority is divided into a predetermined number, and the priority parity packet is extracted. A packet extraction and distribution unit that distributes a high packet to a header and data of the low priority packet or a divided parity bit of the low priority packet;
If the packet with high priority distributed by the packet extraction and distribution unit is subjected to error correction decoding with a predetermined code to determine the presence or absence of a packet error, A first error correction decoding and error detection unit for outputting a packet comprising a later header and data;
When the header and data of the low priority packet are sorted by the packet fetching and sorting unit, error correction decoding is performed with the predetermined code using the header and data to determine the presence or absence of a packet error When it is determined that there is no packet error, a packet composed of the header and data after decoding is output,
When the divided parity bit of the low priority packet is distributed by the packet extraction and distribution unit, the same packet header and data as the low priority packet, and the divided parity bit distributed this time are used. Or, using the header and data of the same packet as the low priority packet, the previously allocated divided parity bit, and the divided parity bit allocated this time, error correction decoding is performed with the predetermined code. Performing a second error correction decoding and error detection unit for outputting a packet composed of a header and data after decoding, if it is determined that there is no packet error;
When the first error correction decoding and error detection unit determines that there is a packet error, the retransmission limit is set to a smaller number for the higher priority packet and to a larger number for the lower priority packet. A return frame including a retransmission request for retransmitting the packet determined to have the packet error within the range of the number of times,
If the second error correction decoding and error detection unit determines that there is a packet error, the divided parity bits that have not been transmitted yet in the packet determined to have the packet error within the range of the retransmission limit number A return frame generation unit that generates a return frame including a retransmission request for transmitting
A transmitter / receiver characterized by comprising:

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