JP2009141836A - Wireless apparatus, and wireless network provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless apparatus capable of improving the probability of rightly receiving a packet even in such a wireless communication environment that fading and interference occur. <P>SOLUTION: A detection means 312 detects presence/absence of error for each of a plurality of blocks constituting a received packet and outputs the result of the detection to a control means 311. The control means 311 outputs the detection result to a control means 321. The control means 321 refers to the detection result from the control means 311 and outputs the detection result to an information generating means 322 when at least one of the plurality of blocks is wrong. On the basis of the detection result, the information generating means 322 broadcasts a retransmission request designating a wireless apparatus to which retransmission of the wrong block is to be requested. The control means 311 then receives the retransmission-requesting block from a transmission source or peripheral wireless apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless device and a wireless network including the wireless device, and more particularly, to a wireless device used for an autonomously established network and a wireless network including the wireless device.

  In a wireless network, multipath fading often occurs. The received power between the two terminals changes in time series due to fading. In the inter-vehicle communication network, each car moves at a high speed, so that the influence of fading is further increased. As a result, there is a possibility that the receiving terminal cannot correctly receive the packet from the transmitting terminal due to fading.

  On the other hand, in a distributed network, a plurality of terminals may determine that the channel is in an idle state and transmit packets simultaneously. In such a case, the receiving terminal cannot correctly receive the packet due to mutual interference between the plurality of packets.

  Generally, when a transmitting terminal transmits a certain packet, the transmitting terminal expects an ACK (Acknowledge) packet from the receiving terminal. When the transmitting terminal does not receive the ACK packet within the specified time, the transmitting terminal retransmits the packet. In the IEEE802.11 MAC layer, the maximum number of retransmissions is defined as “7”.

  When an omnidirectional antenna is used, radio waves from the transmitting terminal propagate in all directions, so that not only the receiving terminal but also peripheral terminals can receive radio waves from the transmitting terminal.

  Conventionally, when the receiving terminal fails to receive a packet transmitted from the transmitting terminal, the relay terminal that exists between the transmitting terminal and the receiving terminal forwards the packet correctly received from the transmitting terminal on behalf of the transmitting terminal, and receives the packet. It has been proposed to improve the re-reception probability at the terminal (Non-Patent Document 1).

  When fading occurs, not all of the packets received by the receiving terminal are broken. Therefore, when the receiving terminal receives a packet that is partially broken, it is inefficient for the transmitting terminal to retransmit the entire packet.

  Therefore, conventionally, it has been proposed that the receiving terminal informs the transmitting terminal of a part that could not be received correctly by a retransmission request message (ARQ), and the transmitting terminal transmits the necessary part to the receiving terminal in response to the retransmission request message. (Non-Patent Document 2).

Further, it has been proposed that the receiving terminal synthesizes the same packet received from different terminals based on the decodable coefficient (Non-Patent Document 3).
C. Yu, KG Shin, and L. Song, “Link-Layer Salvaging for Making Progress in Mobile Ad Hoc Networks,” MobiHoc, 2005. K. Jamieson and H. Balakrishnan, “PPR: Partial Packet Recovery for Wireless Networks,” Sigcomm 2007. GR Woo, P. Kheradpour and D. Katabi, “Beyond the Bits: Cooperative Packet Recovery Using Physical Layer Information,” Mobicom 2007.

  However, in the conventional technology, since both fading and interference are not considered, there is a problem that it is difficult to correctly receive a packet in a wireless communication environment in which fading and interference occur.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a radio apparatus capable of improving the probability of correctly receiving a packet even in a radio communication environment in which fading and interference occur. It is to be.

  Another object of the present invention is to provide a wireless network including a wireless device capable of improving the probability of correctly receiving a packet even in a wireless communication environment in which fading and interference occur.

  According to the present invention, the wireless device is a wireless device that receives a packet from a transmission-source wireless device, and includes a detection unit, a transmission unit, and a reception unit. The detecting means detects the presence / absence of an error in the plurality of blocks of the packet based on the packet composed of the plurality of blocks transmitted from the transmission source wireless device. The transmission means transmits a retransmission request for requesting retransmission of an error block in which an error is detected when an error of at least one block is detected by the detection means. The receiving means receives a block for which retransmission has been requested from a wireless device as a transmission source and a wireless device that has intercepted a packet from the transmission source.

  Preferably, the detection means detects the presence / absence of an error in the plurality of blocks based on an error determination code assigned to each of the plurality of blocks.

  Preferably, the transmission unit transmits a retransmission request by designating an error block and a radio apparatus requesting retransmission of the error block.

  Preferably, the transmission means designates a wireless device that requests retransmission of error blocks in descending order of communication quality with the wireless device.

  Preferably, the wireless device further includes interference detecting means and combining means. The interference detection means detects the presence or absence of interference based on the change width of the correlation value indicating the relevance of the plurality of received signals when the packet is received by the plurality of antennas. The synthesizing unit generates a correct block by synthesizing a plurality of error blocks received from the wireless device from which the receiving unit intercepted a packet from the transmission source and the wireless device from which the packet was received from the transmission source when no interference is detected by the interference detection unit. To do.

  Preferably, the wireless device further includes an interference detection unit, a management unit, and a reception unit. The interference detection means detects the presence or absence of interference based on the change width of the correlation value indicating the relevance of the plurality of received signals when the packet is received by the plurality of antennas. The managing means classifies and manages the first block in which no error is detected by the detecting means and the second block in which the error is detected by the detecting means and no interference is detected by the interference detecting means. . The accepting means accepts the packet received by the receiving means when all the blocks managed by the managing means are the first blocks.

  Preferably, the wireless device further includes interference detection means and estimation means. The interference detection means detects the presence or absence of interference based on the change width of the correlation value indicating the relevance of the plurality of received signals when the packet is received by the plurality of antennas. The estimating means cannot decode the packet received by the receiving means, and when the interference detecting means does not detect the interference, based on the communication quality, the whole of the data and the error correction code added following the data Are estimated from the beginning of the data in such a manner that the lengths of the blocks are shortened in order, and the length of a block that needs to be retransmitted is estimated from among a plurality of blocks each having a unique length. Then, the transmitting unit transmits a retransmission request by designating the block length estimated by the estimating unit. The receiving unit receives a block having a specified length from the wireless device that is the transmission source and the wireless device that has intercepted the packet from the transmission source.

  Preferably, when the interference is detected by the interference detection unit and the length estimated by the estimation unit is longer than the threshold value, the transmission unit specifies a block including data and transmits a retransmission request. The receiving unit receives a block including data from a wireless device as a transmission source and a wireless device that has intercepted a packet from the transmission source.

  According to the present invention, the wireless device is a wireless device that transmits a packet or intercepts a packet from a transmission source, and includes a transmission unit and a retransmission unit. The transmission means transmits a packet including a plurality of blocks. The retransmission means retransmits at least one block when receiving a retransmission request for at least one block of the plurality of blocks.

  Preferably, the retransmission unit retransmits at least one block when the address of the wireless device is included in the retransmission request.

  Preferably, the retransmission means retransmits at least one block according to the priority order included in the retransmission request.

  Preferably, the packet is divided so that the entire data and the error correction code added subsequent to the data are shortened in order from the head of the data, and each of the blocks has a unique length. Consists of. When the retransmission means detects a length for designating a necessary block among the plurality of blocks from the retransmission request, the retransmission means retransmits the block having the detected length.

  Furthermore, according to the present invention, the wireless network includes a first wireless device comprising the wireless device according to any one of claims 1 to 8, and any one of claims 9 to 12. And a second wireless device comprising the wireless device described in 1).

  In this invention, when a part of the packet received by the transmission destination wireless device is wrong, the transmission destination wireless device broadcasts a retransmission request for the erroneous block, and the transmission source wireless device and the transmission source The wireless device that intercepted the packet retransmits the block in response to the retransmission request. As a result, the destination wireless device re-receives the block in which the error was detected from both the source wireless device and the wireless device that intercepted the packet from the source, so that the destination wireless device detects the error. The probability that the processed block reaches the transmission destination wireless device increases.

  Therefore, according to the present invention, it is possible to increase the probability that a transmission destination wireless apparatus correctly receives a packet even in a wireless communication environment where interference and fading occur.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a wireless network according to an embodiment of the present invention. The wireless network 100 according to the embodiment of the present invention is a network that performs a route search in accordance with, for example, OLSR (Optimized Link State Routing) and performs wireless communication along the searched route. The wireless network 100 includes wireless devices M1 to M30. Wireless devices M1 to M30 are mounted on vehicles C1 to C30, respectively, and autonomously configure a wireless network.

  Each of the wireless devices M1 to M30 periodically exchanges position information of a vehicle (any one of the vehicles C1 to C30) on which the wireless device M1 to M30 is mounted. Further, the wireless devices M1 to M30 improve the reception probability at the transmission destination of the packet transmitted from the wireless device of the transmission source by a method described later.

[Embodiment 1]
FIG. 2 is a schematic block diagram showing the configuration of the wireless device M1 shown in FIG. 1 in the first embodiment. The wireless device M1 includes antennas 1 and 2, a communication control unit 3, and a GPS (Global Positioning System) receiver 4.

  The antennas 1 and 2 receive packets from other wireless devices via the wireless communication space, and output the received packets to the communication control unit 3. Further, the antennas 1 and 2 transmit the packet received from the communication control unit 3 to another wireless device via the wireless communication space.

  The communication control unit 3 receives a GPS signal from the GPS receiver 4, and acquires the position of the vehicle on which the wireless device M1 is mounted by a known method based on the received GPS signal.

  And the communication control part 3 produces | generates the Hello message containing the positional information on the vehicle in which self is mounted, and broadcasts the created Hello message with a fixed period (for example, 2 seconds). Moreover, the communication control part 3 receives the Hello message containing the positional information on the vehicle by which another radio | wireless apparatus is mounted from another radio | wireless apparatus.

  And the communication control part 3 detects the radio | wireless apparatus which exists in the circumference | surroundings of self based on the positional information exchanged with the other radio | wireless apparatus, and the positional information on the vehicle in which self was mounted.

  Further, the communication control unit 3 improves the reception probability in the transmission destination wireless device of the packet transmitted from the transmission source wireless device by a method described later.

  The GPS receiver 4 receives a GPS signal from a GPS satellite and outputs the received GPS signal to the communication control unit 3.

  The communication control unit 3 includes a wireless interface module 31, a MAC module 32, a link module 33, an IP module 34, and a GPS module 35.

  The wireless interface module 31 belongs to the physical layer. When the wireless interface module 31 receives a packet from the MAC module 32, the wireless interface module 31 modulates the received packet and transmits the modulated packet to another wireless device via the antennas 1 and 2.

  The wireless interface module 31 receives a packet from another wireless device via the antennas 1 and 2 and demodulates the received packet. Then, the wireless interface module 31 detects the presence or absence of interference for each block of the plurality of blocks constituting the packet based on the two received signals received via the antennas 1 and 2, and performs interference. Only the blocks with no are output to the MAC module 32 and the link module 33.

  The MAC module 32 belongs to the link layer and transfers a packet received from a wireless device that is a transmission source or a wireless device that has intercepted a packet from the transmission source.

  The link module 33 belongs to the link layer, receives a block without interference from the wireless interface module 31, detects the presence or absence of an error in the received block by a method described later, and describes each block based on the detection result. Manage by way.

  Further, the link module 33 determines whether or not the blocks received from the wireless interface module 31 are all the blocks constituting the packet. When the link module 33 determines that the blocks received from the wireless interface module 31 are not all blocks constituting the packet, that is, some of the blocks constituting the packet are missing. At this time, a retransmission request ARQ requesting retransmission of the missing block is generated and broadcasted by a method described later.

  Further, when the link module 33 determines that at least one block is erroneous based on the detection result indicating the presence / absence of an error in the block, a retransmission request ARQ requesting retransmission of the erroneous block is performed by a method described later. Generate and broadcast.

  Further, when the same erroneous block is received from a plurality of wireless devices, the link module 33 combines the erroneous two blocks by a method described later to generate a correct block.

  Further, when the link module 33 receives a retransmission request for a block constituting a packet from another wireless device, the link module 33 retransmits the block in response to the retransmission request.

  Furthermore, when all the blocks constituting the packet are correct, the link module 33 outputs the packet including the correct block to the upper layer.

The IP module 35 belongs to the network layer and receives the position of the vehicle on which the wireless device M1 is mounted from the GPS module 35. Then, the IP module 34 stores the position information P _Self consisting of the received position in a position information table described later. The IP module 34 creates a location information message including the location information P _Self and broadcasts it periodically.

  The GPS module 35 receives a GPS signal from the GPS receiver 4 and detects the position of the vehicle on which the wireless device M1 is mounted based on the received GPS signal by a known method, and the detected position is the IP module. 34.

  Note that each of the wireless devices M2 to M30 illustrated in FIG. 1 has the same configuration as the wireless device M1 illustrated in FIG.

  FIG. 3 is a functional block diagram of the wireless interface module 31, the MAC module 32, and the link module 33 shown in FIG.

  The wireless interface module 31 includes modulation / demodulation means 311, control means 312, and interference detection means 313.

  The MAC module 32 and the link module 33 include a control unit 321, a detection unit 322, a synthesis unit 323, a management unit 324, an information generation unit 325, and a reception unit 326.

  The modem 311 receives a packet from another wireless device via the antennas 1 and 2 and demodulates the received packet. Then, the modem 311 calculates a decodable coefficient DC (Decoding Confidence) for each bit in the packet demodulation process. Then, the modem unit 311 outputs the packet and the decodable coefficient DC to the control unit 312.

  In addition, when the modulation / demodulation unit 311 receives a packet from the control unit 312, the modulation / demodulation unit 311 modulates the received packet, and transmits the modulated packet to another wireless device via the antennas 1 and 2.

  The control unit 312 receives the packet and the decodable coefficient DC from the modulation / demodulation unit 311 and outputs the received packet to the interference detection unit 313. When the control unit 312 receives the detection result of the presence or absence of interference from the interference detection unit 313, the control unit 312 removes the block in which the interference is detected, and outputs the block without interference and the decodable coefficient DC to the control unit 321. .

  This will be specifically described. Assume that the packet is composed of N (N is an integer of 2 or more) blocks 1 to N, and the detection result is composed of [presence of interference: block number]. The presence or absence of interference consists of “F” indicating that there is interference or “NF” indicating that there is no interference. The block number is made up of the number of the block that is subject to detection of the presence or absence of interference.

  When the control unit 312 receives the detection result = [NF / NF / F / NF /... / NF: block 1 / block 2 / block 3 / block 4 /... / Block N] from the interference detection unit 313, , Received detection result = [NF / NF / F / NF /... / NF: block 1 / block 2 / block 3 / block 4 /. A block is detected, and blocks 1, 2, 4 to N excluding block 3 and a decodable coefficient DC are output to the control means 321.

  The control unit 312 receives the packet from the control unit 321 and outputs the received packet to the modulation / demodulation unit 311.

The interference detection unit 313 receives two received signals x ₁ and x ₂ of the packets received by the antennas 1 and ₂ from the control unit 312, and a method to be described later based on the received two signals x ₁ and x _2. Thus, the presence or absence of interference is detected for each of a plurality of blocks constituting the packet, and the detection result = [presence or absence of interference: block number] is output to the control means 312.

  The control means 321 receives K (K is an integer satisfying 1 ≦ K ≦ N) blocks 1 to K and the decodable coefficient DC without interference from the control means 312 and receives the received K blocks 1. ˜K and decodable coefficient DC are output to detection means 322, and K blocks 1 to K are output to information generation means 325.

  In addition, when the control unit 321 receives a retransmission request ARQ of a block constituting the packet from the information generation unit 325, the control unit 321 outputs the received retransmission request ARQ to the control unit 312.

  Further, when the control unit 321 receives the block and the decodable coefficient DC retransmitted in response to the retransmission request ARQ from the control unit 312, the control unit 321 outputs the received block and the decodable coefficient DC to the detection unit 322.

  Further, when receiving a retransmission request ARQ from another wireless device, the control unit 321 outputs the received retransmission request ARQ to the information generation unit 325.

  Further, when the control unit 321 receives a plurality of blocks from the reception unit 326, the control unit 321 transfers a packet including the received plurality of blocks.

  The detection unit 322 receives the K blocks 1 to K and the decodable coefficient DC from the control unit 321. And the detection means 322 detects the presence or absence of an error by the method mentioned later about each of the received K blocks 1-K.

  When the detection unit 322 detects the presence or absence of an error for each of the K blocks 1 to K, the detection unit 322 outputs the detection result to the information generation unit 325. In this case, the detection result is composed of [error presence / absence: block number]. As for the presence / absence of an error, “0” is stored when the block is incorrect, and “1” is stored when the block is not incorrect. The block number is made up of the number of the block that is subject to detection of the presence or absence of an error.

  The detection unit 322 outputs the detection result = [presence / absence of error: block number] and K blocks 1 to K to the management unit 324.

  Further, the detection unit 322 outputs the decodable coefficient DC, the detection result = [presence / absence of error: block number], and K blocks 1 to K to the synthesis unit 323.

  Further, when the detecting unit 322 receives the combined block from the combining unit 323, the detecting unit 322 detects the presence / absence of an error in the received combined block by a method described later, and the detection result = [error presence / absence: block number] and the combined block are detected. The data is output to the management unit 324.

  Combining means 323 receives decodable coefficient DC, detection result = [presence / absence of error: block number] and K blocks 1 to K from detecting means 322. Then, when the synthesizing unit 323 receives the erroneous block from the two wireless devices, the synthesizing unit 323 synthesizes the two erroneous blocks using a decodable coefficient DC by a method described later, and the synthesized block after the synthesis is obtained. Output to the detection means 322.

  The management unit 324 receives the detection result = [presence of error: block number] and K blocks 1 to K from the detection unit 322, and the received detection result = [presence of error: block number] and K blocks. Based on 1 to K, correct blocks and erroneous blocks are classified and managed by a method described later.

Further, the management unit 324 receives the detection result = [presence / absence of error: block number] and the composite block from the detection unit 322, and blocks based on the received detection result = [presence / absence of error: block number] and the composite block. Update management of.
Then, when all of the plurality of blocks included in one packet are correct blocks, the management unit 324 outputs the plurality of blocks to the receiving unit 326.

  The information generation unit 325 receives K blocks 1 to K from the control unit 321 and receives detection results of presence / absence of K blocks 1 to K = [presence / absence of error: block number] from the detection unit 322. Then, the information generation unit 325 determines whether a part of all the blocks 1 to N constituting the packet is missing based on the received K blocks 1 to K. In this case, the information generation unit 325 determines that all of the blocks 1 to N constituting the packet are missing when K <N, and if K = N, It is determined that some of the blocks 1 to N are not missing.

  When the information generating unit 325 determines that a part of all the blocks 1 to N constituting the packet is missing, the information generating unit 325 generates an ARQ1 message requesting retransmission of the missing block by a method described later. Output to the control means 321.

  The information generation unit 325 generates an ARQ1 message requesting retransmission of the erroneous block by a method described later based on the detection result received from the detection unit 322 = [presence / absence of error: block number]. The created ARQ1 message is output to the control means 321.

  In addition, when the information generation unit 325 receives the ARQ1 message from the control unit 321, the information generation unit 325 determines whether or not the received ARQ1 message includes the address of the wireless device in which the information generation unit 325 is mounted, When the device address is included in the ARQ1 message, a block to be retransmitted is acquired from the management unit 324 by a method described later, and a data frame including the block to be retransmitted is generated and output to the control unit 321.

  Receiving means 326, when receiving a plurality of blocks from management means 324, accepts the received plurality of blocks at the radio apparatus and outputs the plurality of blocks to the upper layer.

  Further, the accepting unit 326 outputs a plurality of blocks received from the managing unit 324 to the control unit 321 when the wireless device on which it is mounted is a relay terminal.

  FIG. 4 is a configuration diagram of a position information table held by the IP module 34 shown in FIG. The location information table TBL includes a terminal number and terminal location information. The terminal number and the terminal position information are associated with each other.

  A terminal number consists of the number of the radio | wireless apparatus mounted in the vehicle which has terminal position information. The terminal position information includes position information of a vehicle on which a wireless device represented by a terminal number is mounted.

  FIG. 5 is a diagram showing a format of the location information message. The location information message PSM includes a header HED and messages MS1 and MS2. The header HED includes a transmission source SRC of the location information message PSM and a transmission destination DST. The transmission source SRC is composed of the identification number Self ID of the wireless device that creates the location information message PSM. The transmission destination DST is composed of BROADCAST indicating that the position information message PSM is broadcast.

  The message MS1 includes position information Self position of a vehicle on which a wireless device that generates the position information message PSM is mounted, and a transmission interval. The position information Self position includes an identification number ID of a wireless device that generates the position information message PSM and position information <x, y, T> of the vehicle on which the wireless device that generates the position information message PSM is mounted. The position information <x, y, T> is associated with the identification number ID of the wireless device. The transmission interval is T.

The message MS2 includes the number # neighbor = M of wireless devices adjacent to the wireless device that generates the location information message PSM, the identification numbers ID ₁ and ID _{2 of} the wireless devices adjacent to the wireless device that generates the location information message PSM, It includes position information <x ₁ , y ₁ , T ₁ >, <x ₂ , y ₂ , T ₂ > of a vehicle adjacent to a vehicle on which a wireless device that generates the position information message PSM is mounted. Note that the message MS2 is optional, and is included in the position information message PSM when the wireless device M1 that creates the position information message PSM has the position information of the vehicle C1 and the position information of the vehicle adjacent to the vehicle C1. .

  FIG. 6 is a configuration diagram of the packet PKT in the first embodiment. The packet PKT includes a header and blocks 1 to N. Each of block 1 to block N includes a checksum for detecting the presence or absence of an error in the block.

  FIG. 7 is a configuration diagram of a data frame in the first embodiment. The data frame (DATA1_frame) includes a MAC head, a packet ID, a block indicator, and a payload.

  The MAC header is a conventional MAC header. The packet ID includes a source MAC address, a destination MAC address, and a MAC layer sequence number.

  The block indicator is composed of the number corresponding to the number of blocks included in the payload, and is composed of “1” indicating that each block exists or “0” indicating that each block does not exist.

  The payload consists of a plurality of blocks 1 to N. Each of block 1 to block N includes a checksum.

  FIG. 8 is a configuration diagram of an ARQ frame in the first embodiment. The ARQ frame (ARQ1_frame) includes a MAC head, a packet ID, a block indicator, and a retransmission terminal list.

  The MAC header and packet ID are as described above. The block indicator of the ARQ frame has a number corresponding to the number of blocks included in the payload of the data frame (DATA1_frame), and is “1” indicating that retransmission is necessary or “0” indicating that retransmission is not necessary. Consists of.

  The retransmission terminal list includes addresses of wireless devices that request retransmission of blocks.

  FIG. 9 is a diagram for explaining an interference detection method. Each of the transmission terminal and the reception terminal has the same configuration as that of the radio apparatus M1 shown in FIG.

The transmitting terminal transmits the signal x using the antenna 1. Then, the receiving terminal receives the signal x transmitted from the transmitting terminal through the two antennas 1 and ₂ and obtains _two received signals x ₁ and x ₂ .

The interference detection unit 313 of the receiving terminal receives the two received signals x ₁ and x ₂ from the control unit 312 and a matrix <A> = [x ₁ having the received two received signals x ₁ and x ₂ as components. , X ₂ ]. In this application, <•> represents a matrix.

Then, the interference detection unit 313 of the receiving terminal calculates the correlation matrix <A> ^H <A> using the matrix <A>, and performs eigenvalue decomposition on the calculated correlation matrix <A> ^H <A> to obtain 2 Two eigenvalues σ _MAX and σ _MIN are acquired.

Thereafter, the interference detection means 313 of the receiving terminal calculates K = σ _MAX / σ _MIN to obtain the condition number K.

Since the condition number K is composed of the ratio between the maximum value and the minimum value of the eigenvalues of the correlation matrix <A> ^H <A>, it indicates the strength of the relationship between the _two received signals x ₁ and x ₂ .

  When wireless communication is performed between the transmission terminal and the reception terminal, the condition number K does not change much unless the reception terminal receives a signal other than the signal x from the transmission terminal.

  However, if another terminal transmits the signal y in the same communication range while the receiving terminal is receiving the signal x, the receiving terminal receives interference when receiving the signal x.

As a result, the antennas 1 and 2 of the receiving terminal newly receive the received signals y ₁ and y ₂ , respectively.

Then, the receiving terminal receives the received signal B = [z ₁ , z ₂ ] (z ₁ = x ₁ + y ₁ , z ₂ = x ₂ + y ₂ ) by the antennas 1 and ₂ .

In this case, there is no relationship between the reception signal x ₁ and the reception signal y ₁ and between the reception signal x ₂ and the reception signal y _2, and the reception signal x ₁ and the reception signal are affected by the influence of the radio channel. Since the phase of y ₁ and the phase of reception signal x ₂ and reception signal y ₂ are different, the relationship between reception signal z ₁ and reception signal z ₂ is reduced.

As a result, it changes the condition number _{K B} of the expected value E of the ^{<B> H <B> [} <B> H <B>].

Therefore, the interference detection means 313 of the receiving terminal, a predetermined length (e.g., 50 symbols) the expected value E from the received signal of ^{[<B> H <B>} ], computes its condition number _{K B,} condition number It is possible to detect the presence or absence of interference from fluctuations.

  FIG. 10 is a diagram illustrating the relationship between the condition number and the bit index (Bit index). In FIG. 10, the vertical axis represents the condition number K, and the horizontal axis represents the bit index. A curve k1 shows the relationship between the condition number K and the bit index.

  The condition number K does not change much until the bit index is about 400, and is about “23”, and when the bit index becomes about 500, it greatly fluctuates to “11”.

  Accordingly, the interference detection unit 313 calculates the fluctuation width ΔK of the condition number K obtained by the above-described method, and detects that there is interference when the calculated fluctuation width ΔK is equal to or greater than the threshold value ΔK_th. When ΔK is smaller than the threshold value ΔK_th, it is detected that there is no interference.

  In this way, the interference detection unit 313 determines whether or not there is interference based on the change width ΔK of the correlation value (= condition number K) indicating the strength of relevance between the two received signals received by the two antennas 1 and 2. Is detected.

  Next, demodulatable coefficients used by the synthesizing unit 323 shown in FIG. 3 for synthesizing blocks will be described. Let b be the analog value of each bit included in the block. In the case of ideal BPSK (Binary Phase Shift Keying) modulation, b is “−1” or “1”. In an actual wireless communication environment, the probability p of each bit differs due to fading and can take any value.

  Therefore, the synthesizing unit 323 calculates the ratio between the probability p (b = 1) corresponding to the digital value “1” and the probability p (b = 0) corresponding to the digital value “0”, and the calculation. The logarithm of the ratio (= log (p (b = 1) / (p (b = 0))) is calculated as the logarithmic expected ratio LLR (b).

  Then, the synthesizing unit 323 obtains the calculated logarithmic likelihood ratio LLR (b) as a decodable coefficient DC.

  FIG. 11 is a diagram for explaining a block synthesis method. The receiving terminal receives the erroneous packet PKT_INC from the transmitting terminal and receives the block BLK from the peripheral terminal.

  In this case, the receiving terminal erroneously receives the block 6 of the packet PKT_INC and erroneously receives the block 6 of the block BLK.

  Then, the synthesizing unit 323 of the receiving terminal synthesizes the two erroneous blocks 6 by the following method using the decodable coefficient DC described above.

That is, the analog value of the bit included in the block 6 of the packet PKT_INC is B _S (S represents the transmitting terminal), the demodulator coefficient DC of the analog value B _S is DC _S (B _S ), and the block of the block BLK 6 is B _PH (PH represents a peripheral terminal), and the demodulating coefficient DC of the analog value B _PH is DC _PH (B _PH ), the synthesizing unit 323 has B _N = B _{S * DC S (B S)} + B PH * DC calculates PH the _{(B PH).}

Then, the composition unit 323 determines whether the computed _{B N} is larger than "0", when _{B N} is larger than "0" is set to "1" bit values, _{B N} is When the value is “0” or less, the bit value is set to “0”.

  The synthesizing unit 323 calculates a bit value for the analog value of each bit included in the block 6 by the above-described method, and synthesizes the block 6 included in the packet PKT_INC and the block 6 included in the block BLK. The combining unit 323 stores the combined block as the block 6 and generates the entire packet PKT, and outputs the generated entire packet PKT to the detecting unit 322.

  Next, a method for generating an ARQ1 message will be described. FIG. 12 is a diagram for explaining a method of creating an ARQ1 message. The information generation unit 325 of the wireless device D that is the transmission destination of the packet PKT detects from the detection unit 322 the detection result including [0: BLK1 / 1: BLK2 / 0: BLK3 / 1: BLK4 / 0: BLK5 / 1: BLK6]. Block 2, 4 and 6 are erroneous based on the received detection result = [0: BLK1 / 1: BLK2 / 0: BLK3 / 1: BLK4 / 0: BLK5 / 1: BLK6]. And a block indicator consisting of [0/1/0/1/0/1] is stored in ARQ1_frame.

  Further, the information generation unit 325 of the wireless device D acquires the position information table TBL from the IP module 34, and the wireless devices A and B existing around the wireless device D based on the acquired position information table TBL. , C addresses Add_A, Add_B, and Add_C, and the address Add_S of the source wireless device S are detected.

  Further, the information generation unit 325 of the wireless device D acquires the communication quality (for example, received signal strength RSSI) between the detected wireless devices A to C, S and the wireless device D from the wireless interface module 31.

  Then, the information generation means 325 of the wireless device D transmits the addresses Add_A, Add_B, Add_C, and Add_S of the wireless devices A to C and S in the descending order of the acquired received signal strength RSSI, that is, in descending order of communication quality, the retransmission terminal list. And ARQ1_frame is created. In this case, the information generation unit 325 of the wireless device D assigns priorities to the wireless device A, the wireless device B, the wireless device C, and the wireless device S in this order, and the addresses Add_A, Add_B, Add_C of the wireless devices A to C, S, Add_S is stored in the retransmission terminal list.

  Note that the information generation unit 325 of the wireless device D always stores the address of the transmission source wireless device in the retransmission terminal list.

  As described above, the information generating unit 325 designates a retransmission terminal for requesting retransmission of an erroneous block with priority.

  FIG. 13 is a diagram for explaining operations from packet transmission to block retransmission. The transmission-source wireless device S transmits the data frame DATA1. Then, the wireless device D of the transmission destination creates the ARQ1 message by the above-described method because the blocks 2, 4, and 6 of the data frame DATA1 received from the wireless device S are incorrect, and after the SIFS has passed, the ARQ1 message is generated. Broadcast.

  The wireless devices A to C and the transmitting wireless device S existing around the wireless device D receive the ARQ1 message. Then, the wireless devices A to C and S detect that retransmission of the blocks 2, 4 and 6 is requested with reference to the block indicator of the ARQ1 message.

  However, since the wireless device A having the first priority does not respond to the ARQ1 message, the wireless device B having the second highest priority creates the data frame DATA2 including the blocks 2 and 6. Data frame DATA2 is transmitted in synchronization with the second slot SLOT after the SIFS has elapsed.

  Then, the wireless devices C and S receive the data frame DATA2 and detect that the blocks 2 and 6 are retransmitted.

  Then, since the wireless device C having the third highest priority has not correctly received the erroneous block 4 other than the blocks 2 and 6, the wireless device C stops retransmission of the data frame.

  The source wireless device S having the lowest priority creates a data frame DATA3 including the block 4, sets a slot SLOT in synchronization with the progress of SIFS, and transmits the created data frame DATA3.

  As a result, the destination wireless device D re-receives blocks 2 and 6 from the wireless device B and re-receives block 4 from the wireless device S.

  As described above, according to the present invention, not only a transmission source wireless device but also a wireless device that intercepts a packet from the transmission source between the transmission source and the transmission destination is a block with an error from the transmission destination wireless device. In response to the retransmission request, the block is retransmitted.

  As a result, even in a wireless communication environment in which interference and fading occur, there is a high probability that a block requested to be retransmitted will reach the transmission destination.

  Therefore, according to the present invention, even in a wireless communication environment where interference and fading occur, it is possible to increase the probability of correctly receiving a packet in a destination wireless device.

  FIG. 14 is a configuration diagram of the management table. The management table MGET includes a flag flag and blocks belonging to the same packet. The flag flag consists of “1” indicating that the block is correct, or “0” indicating that the block is incorrect and there is no interference.

  If there is no error, each block is stored in the column of the block belonging to the same packet corresponding to the flag flag = 1. If there is an error and there is no interference, the flag flag = 0 together with the decodable coefficient DC. Are stored in the column of blocks belonging to the same packet.

  Upon receiving the detection result = [error presence / absence: block number] and K blocks 1 to K from the detection means 322, the management means 324 receives the detection result = [error Based on the presence / absence: block number] and the K blocks 1 to K, a management table MGET is created to manage each block.

  The management means 324 creates a management table MGET for each packet and manages the blocks for each packet.

  FIG. 15 is a flowchart for illustrating a communication method according to the first embodiment of the present invention. When a series of operations is started, the transmission source wireless device S creates a packet including the plurality of blocks described above and transmits the packet to the transmission destination (step S1).

  Then, the destination wireless device D receives the packet (step S2). The modem unit 311 of the radio apparatus D demodulates the received packet and outputs the demodulated packet and the decodable coefficient DC to the control unit 312. The control unit 312 of the wireless device D receives the packet and the decodable coefficient DC from the modulation / demodulation unit 311 and outputs the received packet to the interference detection unit 313. The interference detection unit 313 is based on the packet received from the control unit 312. Then, the presence or absence of interference is detected by the method described above (step S3), and the detection result = [presence or absence of interference: block number] is output to the control means 312.

  Then, the control unit 312 of the wireless device D, based on the detection result received from the interference detection unit 313 = [presence / absence of interference: block number], of the plurality of blocks 1 to N constituting the packet, K without interference. The blocks 1 to K are detected (step S4), and the detected K blocks 1 to K and the decodable coefficient DC are output to the control means 321.

  The control unit 321 of the wireless device D receives the K blocks 1 to K and the decodable coefficient DC from the control unit 312, and outputs the received K blocks 1 to K and the decodable coefficient DC to the detection unit 322. .

  Then, the detection unit 322 of the wireless device D receives the K blocks 1 to K and the decodable coefficient DC from the control unit 321, and performs error detection on each of the received K blocks 1 to K by the method described above. (Step S5), the detection result = [error presence / absence: block number] is output to the information generating means 325, and the detection result = [error presence / absence: block number] and the K blocks 1 to K are detected. Is output to the management unit 324, and the detection result = [presence / absence of error: block number], K blocks 1 to K, and decodable coefficient DC are output to the combining unit 323.

  Thereafter, the management unit 324 of the wireless device D manages each block based on the detection result = [presence / absence of error: block number] and the K blocks 1 to K (step S6).

  Then, the information generation unit 325 of the wireless device D determines whether any of the K blocks 1 to K has an error based on the detection result = [presence / absence of error: block number] (step S7). ).

  When it is determined in step S7 that there are no errors for the K blocks 1 to K, the series of operations proceeds to step S15.

  On the other hand, when it is determined in step S7 that there are errors in the K blocks 1 to K, the information generation unit 325 manages the detection result received from the detection unit 322 = [error presence / absence: block number]. Based on the K blocks 1 to K managed by the means 324, the position information table TBL received from the upper layer, and the communication quality (= received signal strength RSSI) received from the wireless interface module 31, The method creates an ARQ1 message, outputs the created ARQ1 message to the control means 321 and broadcasts the ARQ1 message (step S8).

  The wireless device S and the wireless device R receive the ARQ1 message transmitted from the wireless device D. (Step S9). Then, when the wireless device S and the wireless device R include their own addresses in the ARQ1 message, the wireless devices S and R create and transmit data frames according to the priority order specified in the ARQ1 message (step S10).

  In this case, the wireless device S and the wireless device R transmit the blocks requested in the data frame by excluding the blocks already retransmitted by the wireless device having a higher priority than itself.

  Then, the wireless device D receives the data frame (step S11), the modulation / demodulation unit 311 of the wireless device D demodulates the received data frame, and the demodulated data frame and the decodable coefficient DC to the control unit 312. Output.

  The control unit 312 of the wireless device D receives the data frame and the decodable coefficient DC from the modulation / demodulation unit 311 and outputs the received data frame to the interference detection unit 313.

  Then, the interference detection unit 313 of the wireless device D detects the presence / absence of interference for each block based on the blocks included in the data frame received from the control unit 312, and the detection result = [interference]. Or not: block number] is output to the control means 312.

  Then, the control unit 312 of the wireless device D detects a block without interference based on the detection result = [presence / absence of interference: block number] and the data frame (step S12), and detects the detected block and the decodable coefficient DC. Are output to the control means 321.

  Then, the control unit 321 of the radio apparatus D receives the block without interference and the decodable coefficient DC from the control unit 312, and outputs the received block and decodable coefficient DC to the detection unit 322.

  The detection unit 322 of the wireless device D receives the block and the decodable coefficient DC from the control unit 321, detects the presence / absence of an error for the received block, and determines whether there is an error for the block (step S <b> 13). ).

  When it is determined in step S13 that there is an error, the detection unit 322 of the wireless device D outputs the detection result = [presence / absence of error: block number], the block, and the decodable coefficient DC to the synthesis unit 323. Then, the synthesizing unit 323 of the wireless device D receives the detection result = [presence / absence of error: block number], the block and the decodable coefficient DC, and the received detection result = [presence / absence of error: block number], block and decoding. Based on the possible coefficient DC, the erroneous block is synthesized (step S14), and the synthesized block is outputted to the detecting means 322.

  Thereafter, the detection unit 322 of the wireless device D detects the presence or absence of an error in the combined block received from the combining unit 323 by the method described above. And a series of operation | movement transfers to step S13 mentioned above.

  Thereafter, when it is determined in step S13 that there is no error, the series of operations proceeds to step S15.

  After “NO” in step S 7, the detection unit 322 of the wireless device D outputs the detection result = [presence of error: block number] and K blocks 1 to K to the management unit 324. Then, the management unit 324 of the wireless device D uses the above-described method based on the detection result = [presence / absence of error: block number] received from the detection unit 322 and the K blocks 1 to K in accordance with the method described above. ˜K are registered and managed in the management table MGET (step S15).

  Further, after “NO” in step S 13, the detection unit 322 of the wireless device D outputs the detection result = [presence of error: block number] and the block to the management unit 324. Then, the management unit 324 of the wireless device D updates the management table MGET based on the detection result = [presence / absence of error: block number] and the block received from the detection unit 322, and manages each block (step S15).

  Thereafter, the management unit 324 of the wireless device D determines whether all the blocks are correct (step S16). When it is determined in step S16 that all blocks included in one packet are correct, the management unit 324 of the wireless device D outputs all the blocks to the receiving unit 326, and the receiving unit 326 That is, the entire packet) is received (step S17), and all the received blocks are output to the upper layer.

  Then, when it is determined in step S16 that at least one block of the plurality of blocks included in one packet is not correct, or after step S17, the series of operations ends.

  When it is determined in step S16 that at least one block of a plurality of blocks included in one packet is not correct, steps S8 to S8 in FIG. 15 are performed until all blocks included in one packet are correct. S17 is repeatedly executed.

  When wireless devices M1 to M30 constituting wireless network 100 receive a packet from a wireless device as a transmission source according to the flowchart shown in FIG. 15, and at least some of a plurality of blocks constituting the received packet are incorrect Sends a retransmission request for an erroneous block to the source wireless device and the wireless device that intercepted the packet from the source, and requested retransmission from the source wireless device and the wireless device that intercepted the packet from the source. Re-receive received block.

  As a result, each of the wireless devices M1 to M30 re-receives a block from a plurality of wireless devices.

  Therefore, according to the present invention, it is possible to increase the probability that a correct block can be received in the transmission destination radio apparatus.

  Further, when requesting retransmission of an erroneous block, each of the wireless devices M1 to M30 designates the wireless device requesting retransmission in descending order of communication quality with itself, and the wireless device requested to retransmit the retransmission The requested blocks are retransmitted in descending order of communication quality with the destination wireless device.

  Therefore, according to the present invention, it is possible to increase the probability that a correct block can be received in the transmission destination radio apparatus.

  Further, among the plurality of wireless devices requested to retransmit the block, the wireless device having the second highest priority excludes the blocks already retransmitted by the higher-order wireless device and retransmits the blocks.

  Therefore, according to the present invention, block retransmission can be performed efficiently.

  Furthermore, each radio | wireless apparatus M1-M30 synthesize | combines a block using the decodable coefficient DC, when there is no interference.

  Therefore, according to the present invention, blocks constituting a packet can be synthesized using the decodable coefficient DC even in a wireless communication environment in which interference occurs.

[Embodiment 2]
FIG. 16 is a schematic block diagram showing a configuration of the radio apparatus M1 shown in FIG. 1 in the second embodiment. In the second embodiment, the wireless device M1 includes antennas 1 and 2, a communication control unit 3A, and a GPS receiver 4, as shown in FIG. That is, in the second embodiment, wireless device M1 has a configuration in which communication control unit 3 shown in FIG. 2 is replaced with communication control unit 3A.

  The communication control unit 3A is the same as the communication control unit 3 except that the MAC module 32 and the link module 33 of the communication control unit 3 shown in FIG.

  FIG. 17 is a functional block diagram of the wireless interface module 31, the MAC module 32A, and the link module 33A shown in FIG.

  The MAC module 32A and the link module 33A are obtained by replacing the information generating unit 325 of the MAC module 32 and the link module 33 shown in FIG. 3 with the information generating unit 325A and deleting the combining unit 323. This is the same as the link module 33. In the second embodiment, the detection means 322 detects the presence or absence of data errors after decoding using all payloads received up to the present time, and outputs the detection result to the information generation means 325A.

  Upon receiving the detection result indicating data error = [presence of error: length of all payloads received so far] from the detection unit 322, the information generation unit 325A receives an ARQ2 message that is a retransmission request in the second embodiment. Is generated by a method to be described later, and the generated ARQ2 message is output to the control means 321.

  Note that each of radio apparatuses M2 to M30 shown in FIG. 1 has the configuration shown in FIGS. 16 and 17 in the second embodiment.

  FIG. 18 is a configuration diagram of a packet in the second embodiment. The packet PKT includes data and an RCPC (Rate Compatible Punctured Convolutional) code. The RCPC code is an error correction code.

  Then, the packet PKT is divided into payloads 1 to 3 from the data and the RCPC code. In this case, payload 1 starts from Start = 0, has a length of 512 bytes, and consists of data and a part of RCPC code. Payload 2 starts from Start = 512, has a length of 128 bytes, and is composed of a part of RCPC code. Further, the payload 3 starts from Start = 640, has a length of 100 bytes, and includes a part of RCPC code. The data includes a checksum.

  As described above, the payloads 1 to 3 are sequentially generated so that the length becomes shorter. Since the payload 1 is composed of data and a part of the RCPC code, the transmission destination wireless device can decode the packet PKT if it receives the payload 1 without receiving the entire packet PKT.

  FIG. 19 is a configuration diagram of a data frame in the second embodiment. The data frame DATA2_frame in Embodiment 2 is the same as the data frame DATA1_frame shown in FIG. 7 except that the block indicator of the data frame DATA1_frame shown in FIG. 7 is changed.

  In the second embodiment, the block indicator is made up of Start and Length. The Start is composed of the start bits of the payloads 1 to 3, and the Length is composed of the lengths of the payloads 1 to 3. Therefore, in the second embodiment, the block indicator designates one of payloads 1 to 3 shown in FIG.

  FIG. 20 is a configuration diagram of an ARQ2 message in the second embodiment. ARQ2_frame in the second embodiment is the same as data frame ARQ1_frame shown in FIG. 8 except that the block indicator of data frame ARQ1_frame shown in FIG. 8 is changed.

  The block indicator included in ARQ2_frame is the same as the block indicator included in DATA2_frame.

  In the second embodiment, the transmission source radio apparatus divides one packet into a plurality of parts (payloads 1 to 3) as shown in FIG. 18, and firstly, the first part (payload 1) is the transmission destination. To the wireless device.

  If the transmission destination wireless device can correctly decode the data portion, the transmission destination wireless device transmits an ARQ2 message having a length of “0” to the transmission source wireless device.

  If the transmission destination wireless device cannot correctly decode the data portion, it creates an ARQ2 message requesting retransmission of the payload by the following method.

  The decoding probability depends on the length of the data, the length of the payload and the signal to noise ratio. Therefore, if the relationship between the data length, payload length, signal-to-noise ratio, and decoding probability is used, the decoding probability of data with a known length is set to a specified threshold value at a fixed signal-to-noise ratio. The payload necessary to reach can be calculated.

  Therefore, the information generation unit 325A estimates the length of the payload necessary for correctly decoding the data based on the signal-to-noise ratio when the received payload cannot decode the data and there is no interference. Create an ARQ2 message with length.

  In addition, when the interference occurs or the estimated information length exceeds the threshold value Lth, the information generation unit 325A includes Start = 0 and Length = −1 for designating the payload 1 in the block indicator. Generate a message. Note that Start = 0 and Length = −1 specify payload 1. That is, Start = 0 and Length = −1 are requests for retransmission of a payload including data, not a payload including only an RCPC code.

  If the wireless device that intercepts the packet from the transmission source can correctly receive the payload 1 from the wireless device of the transmission source, it can calculate the payloads 2 and 3. Therefore, the wireless device that intercepts the packet from the transmission source can retransmit any of the payloads 1 to 3 according to the ARQ2 message.

  The threshold value Lth is determined in advance as a system parameter of the wireless network 100.

  The method for specifying the wireless device that requests retransmission of the payload is the same as the method for specifying the wireless device in the first embodiment.

  FIG. 21 is a diagram for explaining operations from packet transmission to payload retransmission. The transmission-source wireless device S transmits the data frame DATA4. Then, since the payload 1 of the data frame DATA4 received from the wireless device S is incorrect, the transmission destination wireless device D creates an ARQ2 message requesting retransmission of the payload 2 by the method described above, and after the SIFS has elapsed. Broadcast an ARQ2 message.

  The wireless devices A to C and the transmitting wireless device S existing around the wireless device D receive the ARQ2 message. Then, the wireless devices A to C and S detect that the retransmission of the payload 2 is requested with reference to the block indicator of the ARQ2 message.

  However, since the wireless device A with the highest priority does not respond to the ARQ2 message, the wireless device B with the second highest priority creates the data frame DATA5 including the payload 2, and the SIFS The slot SLOT is set in synchronization with the progress, and the data frame DATA5 is transmitted.

  As a result, the destination wireless device D re-receives the payload 2 from the wireless device B. Then, the wireless device D decodes the data using the payload 1 received from the transmission source S and the payload 2 received from the wireless device B.

  As described above, according to the present invention, not only a wireless device as a transmission source but also a wireless device that intercepts a packet from a transmission source between a transmission source and a transmission destination includes an erroneous payload from the transmission destination wireless device. The payload is retransmitted in response to the retransmission request.

  As a result, even in a wireless communication environment where interference and fading occur, there is a high probability that an erroneous payload will reach the destination.

  Therefore, according to the present invention, even in a wireless communication environment where interference and fading occur, it is possible to increase the probability of correctly receiving a packet in a destination wireless device.

  FIG. 22 is a flowchart for illustrating a communication method according to the second embodiment of the present invention. The flowchart shown in FIG. 22 is obtained by deleting step S5 from the flowchart shown in FIG. 15 and replacing steps S1, S3, S4, S8 to S10, and S12 with steps S1A, S3A, S4A, S8A to S10A, and S12A, respectively. Others are the same as the flowchart shown in FIG.

  When a series of operations is started, the transmission source wireless device S generates a packet including the payload 1, and transmits the generated packet to the transmission destination wireless device D (step S1A). Thereafter, step S2 described above is executed.

  Then, in the destination wireless device D, the control unit 312 detects the payload 1 without interference based on the detection result from the interference detection unit 313 (step S3A).

  Thereafter, the control unit 312 of the wireless device D outputs the payload 1 without interference to the control unit 321, and the control unit 321 outputs the payload 1 received from the control unit 312 to the detection unit 322.

  Then, the detection unit 322 of the wireless device D detects whether there is an error in the data decoded from the payload 1 received from the control unit 321 (step S4A). Thereafter, steps S6 and S7 described above are sequentially executed.

  When it is determined in step S7 that there is an error in the decoded data, the information generation unit 325A of the wireless device D uses the above-described method based on the communication quality (= signal-to-noise ratio) and the position information table TBL. An ARQ2 message is created, and the created ARQ2 message is broadcast via the control means 321, 312, the modulation / demodulation means 311 and the antennas 1 and 2 (step S8A).

  Then, the wireless device S and the wireless device R receive the ARQ21 message transmitted from the wireless device D. (Step S9A). Thereafter, when the wireless device S and the wireless device R include their own addresses in the ARQ2 message, the wireless devices S and R create and transmit data frames according to the priority order specified in the ARQ2 message (step S10A).

  Then, the above-described step S11 is executed, and then the wireless device D detects a payload without interference by the same operation as the operation in step S3A (step S12A). And step S13 mentioned above is performed.

  When it is determined in step S13 that there is a data error, the series of operations returns to step S8A.

  If it is determined in step S13 that there is no data error, the series of operations proceeds to step S15.

  After “NO” in step S7 or “NO” in step S13, the above-described steps S15 to S17 are sequentially executed, and a series of operations is completed.

  When the wireless devices M1 to M30 configuring the wireless network 100 receive a packet including the payload 1 from the transmission source wireless device according to the flowchart illustrated in FIG. 22, and when the payload 1 configuring the received packet is incorrect A payload retransmission request is transmitted to the transmission source wireless device and the wireless device that intercepted the packet from the transmission source, and the payload is re-received from the transmission source wireless device and the wireless device that intercepted the packet from the transmission source.

  As a result, each of the wireless devices M1 to M30 re-receives the payload from the plurality of wireless devices.

  Therefore, according to the present invention, it is possible to increase the probability that a correct payload can be received by the destination wireless device.

  Others are the same as in the first embodiment.

  In the above description, the radio apparatuses M1 to M30 have been described as being mounted on a vehicle. However, the present invention is not limited to this, and the radio apparatuses M1 to M30 may be stationary. In this case, each of the wireless devices M1 to M30 does not need the GPS receiver 4, and detects a wireless device existing in the vicinity of the wireless device by transmitting and receiving a Hello message.

  In the present invention, the information generation unit 325 and the control unit 321 or the information generation unit 325A and the control unit 321 constitute a “transmission unit”.

  Further, the control means 312 and 321 that receive the data frame in response to the retransmission request constitute “reception means”.

  Further, the information generation means 325A for estimating the length of the payload requesting retransmission constitutes “estimation means”.

  Further, the payloads 1 to 3 constitute “a plurality of blocks”.

  Further, the information generating means 325 and the control means 321 for transmitting the data frame in response to the ARQ1 message or the ARQ2 message, or the information generating means 325A and the control means 321 constitute a “retransmission means”.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a radio apparatus capable of improving the probability of correctly receiving a packet even in a radio communication environment where fading and interference occur. The present invention is also applied to a wireless network including a wireless device capable of improving the probability of correctly receiving a packet even in a wireless communication environment where fading and interference occur.

1 is a schematic diagram of a wireless network according to an embodiment of the present invention. FIG. 2 is a schematic block diagram illustrating a configuration of the wireless device illustrated in FIG. 1 in the first embodiment. FIG. 3 is a functional block diagram of a wireless interface module, a MAC module, and a link module shown in FIG. 2. FIG. 3 is a configuration diagram of a position information table held by the IP module shown in FIG. 2. It is a figure which shows the format of a positional info message. FIG. 3 is a configuration diagram of a packet in the first embodiment. 3 is a configuration diagram of a data frame according to Embodiment 1. FIG. 3 is a configuration diagram of an ARQ frame in Embodiment 1. FIG. It is a figure for demonstrating the detection method of interference. It is a figure which shows the relationship between a condition number and a bit index (Bit index). It is a figure for demonstrating the synthetic | combination method of a block. It is a figure for demonstrating the preparation method of an ARQ1 message. It is a figure for demonstrating operation | movement from transmission of a packet to resending of a block. It is a block diagram of a management table. It is a flowchart for demonstrating the communication method by Embodiment 1 of this invention. FIG. 3 is a schematic block diagram illustrating a configuration of a wireless device illustrated in FIG. 1 in a second embodiment. FIG. 17 is a functional block diagram of a wireless interface module, a MAC module, and a link module shown in FIG. 16. FIG. 11 is a configuration diagram of a packet in the second embodiment. 6 is a configuration diagram of a data frame in Embodiment 2. FIG. FIG. 10 is a configuration diagram of an ARQ2 message in the second embodiment. It is a figure for demonstrating the operation | movement from transmission of a packet to retransmission of a payload. It is a flowchart for demonstrating the communication method by Embodiment 2 of this invention.

Explanation of symbols

  1, 2 antenna, 3, 3A communication control unit, 4 GPS receiver, 31 wireless interface module, 32, 32A MAC module, 33, 33A link module, 34 IP module, 34 GPS module, 100 wireless network, 311 modulation / demodulation means, 312, 321 Control means, 313 interference detection means, 322 detection means, 323 composition means, 324 management means, 325, 325A information generation means, 326 acceptance means.

Claims (13)

A wireless device that receives a packet from a wireless device as a transmission source,
Detecting means for detecting presence / absence of errors in a plurality of blocks of the packet based on a packet consisting of a plurality of blocks transmitted from the transmission source wireless device;
Transmitting means for transmitting a retransmission request for requesting retransmission of the error block in which the error is detected when an error of at least one block is detected by the detecting means;
A wireless device comprising: a wireless device that is the transmission source; and a reception unit that receives the block that requested the retransmission from a wireless device that intercepted a packet from the transmission source.   The radio apparatus according to claim 1, wherein the detection unit detects the presence / absence of the error in the plurality of blocks based on an error determination code assigned to each of the plurality of blocks.   The radio apparatus according to claim 1, wherein the transmission unit transmits the retransmission request by designating the error block and a radio apparatus requesting retransmission of the error block.   The radio apparatus according to claim 3, wherein the transmission unit specifies a radio apparatus that requests retransmission of the error block in descending order of communication quality with the radio apparatus. Interference detecting means for detecting the presence or absence of interference based on a change width of a correlation value indicating a degree of relevance of a plurality of received signals when the packet is received by a plurality of antennas;
When no interference is detected by the interference detection unit, the reception unit generates a correct block by combining a plurality of error blocks received from the transmission source wireless device and the wireless device that intercepted the packet from the transmission source. The wireless apparatus according to claim 1, further comprising: a combining unit that performs the operation. Interference detecting means for detecting the presence or absence of interference based on a change width of a correlation value indicating a degree of relevance of a plurality of received signals when the packet is received by a plurality of antennas;
A first block in which the error is not detected by the detection unit and a second block in which the error is detected by the detection unit and the interference is not detected by the interference detection unit are classified. Management means to manage;
The radio apparatus according to claim 1, further comprising: a reception unit that receives a packet received by the reception unit when all of the blocks managed by the management unit are the first block. Interference detecting means for detecting the presence or absence of interference based on a change width of a correlation value indicating a degree of relevance of a plurality of received signals when the packet is received by a plurality of antennas;
When the packet received by the reception unit cannot be decoded and the interference detection unit does not detect the interference, based on communication quality, the entire data and the error correction code added following the data And an estimation means for estimating a length of a block that needs to be retransmitted from among the plurality of blocks each having a unique length. ,
The transmitting unit transmits the retransmission request by designating a length of the block estimated by the estimating unit;
The wireless device according to claim 1, wherein the reception unit receives the block having the designated length from the wireless device that is the transmission source and the wireless device that has intercepted a packet from the transmission source. When the interference is detected by the interference detection unit and the length estimated by the estimation unit is longer than a threshold value, the transmission unit specifies the block including data and transmits the retransmission request.
The radio apparatus according to claim 7, wherein the reception unit receives a block including the data from the radio apparatus of the transmission source and a radio apparatus that has intercepted a packet from the transmission source. A wireless device that transmits packets or intercepts packets from the source,
Transmitting means for transmitting a packet including a plurality of blocks;
A radio apparatus comprising: a retransmission unit configured to retransmit the at least one block when receiving a retransmission request of at least one block of the plurality of blocks.   The wireless device according to claim 9, wherein the retransmission means retransmits the at least one block when an address of the wireless device is included in the retransmission request.   The radio apparatus according to claim 10, wherein the retransmission section retransmits the at least one block according to a priority order included in the retransmission request. The packet is divided such that the entire data and an error correction code added subsequent to the data are shortened in order from the top of the data, and each of the packets has a unique length. Consisting of blocks,
The radio apparatus according to claim 9, wherein the retransmission unit retransmits a block having the detected length when detecting a length for designating a necessary block among the plurality of blocks from the retransmission request. . A first wireless device comprising the wireless device according to any one of claims 1 to 8,
A wireless network comprising: a second wireless device including the wireless device according to any one of claims 9 to 12.

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