JP2008042338A - Error correction method for vehicle-to-vehicle communication, and vehicle-to-vehicle communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an error correction method for a vehicle-to-vehicle communication by which a high communication quality can be secured, and to provide the vehicle-to-vehicle communication system. <P>SOLUTION: The vehicle-to-vehicle communication system comprises: a reception signal state estimation means for estimating the reception signal state of reception signals when receiving reception information included in the packet of another vehicle on the basis of information for reception signal level estimation included in the packet of another vehicle; a reception information generation means for generating new reception information on the basis of the estimated reception signal state and the reception information included in the packet of another vehicle; a punctured decoding means for executing punctured decoding relating to a punctured code to the new reception information; an error correction decoding means for executing error correction decoding relating to an error correction code to the result of punctured decoding processing; and an error detection decoding means for executing error detection decoding relating to an error detection code to the result of error correction decoding processing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an error correction method in vehicle-to-vehicle communication in which information is mutually exchanged between vehicles by wireless communication, and a vehicle-to-vehicle communication system.

In the inter-vehicle communication system, a plurality of vehicles exchange vehicle control information such as their own vehicle position and speed with a constant update cycle. Such a vehicle-to-vehicle communication system is a safety support system (see, for example, Patent Document 1 and Patent Document 2) that prevents encounter accidents, right-straight accidents, and rear-end collisions, and comfort / entertainment for exchanging moving images, audio information, and the like. This is used for a system system (for example, see Patent Document 3).
JP 2006-126949 A JP 2006-99453 A JP 2005-134500 A

  However, in the conventional inter-vehicle communication system, the communication quality significantly deteriorates due to the influence of multipath and the like because the arrangement of vehicles in communication (communication vehicle arrangement) and the surrounding building arrangement change. Therefore, an error correction method that ensures high communication quality is required.

  Further, in the conventional inter-vehicle communication system, when a highly redundant error correction method is used in order to improve communication quality, the number of communicable vehicles in the communication area is reduced, resulting in deterioration of communication quality. Therefore, there is a need for an error correction method that ensures the number of communicable vehicles and ensures high communication quality even when the number of communication vehicles increases.

  Accordingly, an object of the present invention is to provide an error correction method and an inter-vehicle communication system in inter-vehicle communication that can ensure high communication quality.

  An error correction method in inter-vehicle communication according to a first aspect of the present invention is a transmission signal transmitted from another vehicle, and received information and received signal level estimation information related to estimation of the received signal level of the received information when the received information is received. A reception signal when receiving the reception information included in the other vehicle packet based on the packet reception step for receiving the other vehicle packet including the received signal level estimation information included in the received other vehicle packet Received signal state estimating step for estimating the received signal state of the received signal, and received information for generating new received information based on the received signal state estimated by the received signal state estimating step and the received information included in the other vehicle packet A generation step, and a puncture decoding step for performing puncture decoding related to the puncture code for the new reception information; An error correction decoding step for performing error correction decoding related to an error correction code on a result of the puncture decoding process by the puncture decoding step, and an error correction decoding process result by the error correction decoding step. An error detection decoding step for performing error detection decoding on the error detection code, and performing error correction of the received other vehicle packet based on a result of the error detection decoding processing by the error detection decoding step Features.

  An inter-vehicle communication system according to a second aspect of the present invention includes an other vehicle that is transmitted from another vehicle and includes received information and received signal level estimation information related to estimation of the received signal level of the received information when the received information is received. Based on the packet receiving means for receiving the packet and the received signal level estimation information included in the received other vehicle packet, the received signal of the received signal when receiving the received information included in the other vehicle packet A reception signal state estimation unit for estimating a state; a reception information generation unit for generating new reception information based on the reception signal state estimated by the reception signal state estimation unit and the reception information included in the other vehicle packet; Puncture decoding means for performing puncture decoding related to the puncture code for the new received information, and the puncture decoding means Error correction decoding means for performing error correction decoding on the error correction code for the result of the failure decoding process, and error detection on the error detection code for the result of the error correction decoding process by the error correction decoding means Error detection decoding means for performing decoding, and performing error correction on the received packet based on the result of error detection decoding processing by the error detection decoding means.

  A vehicle-to-vehicle communication system according to a third aspect of the invention includes transmission information generation means for generating first transmission information, and an error detection code for generating second transmission information by adding an error detection code to the first transmission information. And error correction coding means for performing error correction coding related to an error correction code on the second transmission information and generating third transmission information after the error correction coding, and the third transmission information Puncture coding means for performing puncture coding related to a puncture code for partially thinning out information in the transmission information and generating fourth transmission information after puncture coding, and own vehicle identification information for generating own vehicle identification information Generating means, own vehicle transmission information identification information generating means for generating own vehicle transmission information identification information related to the first transmission information, continuous sending means for transmitting a packet related to the first transmission information one or more times, Generates continuous transmission number generating means for generating own vehicle continuous number information relating to the number of transmissions, continuous number generating means for generating own vehicle continuous number information relating to the serial number, and generating first reception signal state estimation information First reception signal state estimation information generating means, the first reception signal state estimation information, the own vehicle identification information, the own vehicle transmission information identification information, the own vehicle transmission frequency information, the own vehicle The own vehicle packet generating means for generating the own vehicle packet using the serial number information and the fourth transmission information, the packet transmitting means for transmitting the own vehicle packet, and the other vehicle packet transmitted from the other vehicle are received. Other vehicle packet receiving means, information extracting means for extracting other vehicle identification information, other vehicle transmission information identification information, other vehicle transmission number information and other vehicle serial number information from the other vehicle packet, Second reception signal state estimation information generating means for generating quantized second reception signal state estimation information related to reception signal information estimation information based on the vehicle packet; and a reception signal based on the other vehicle packet First received information generating means for generating quantized first received information and the second received signal state estimating information based on the second received signal state estimating information Processing means for obtaining a first received signal state representing the amplitude of the received signal, and a second received signal state when receiving the first received information based on the first received signal state Received signal state estimating means for estimating, second received information generating means for generating second received information based on the second received signal state and the first received information, and the second received information On the other hand, puncture recovery for puncture codes And puncture decoding means for generating third received information after puncture decoding, error correction decoding related to an error correction code on the third received information, and error correction decoding Error correction decoding means for generating later fourth received information, error detection decoding relating to an error detection code is performed on the fourth received information, and fifth received information after error detection decoding is obtained. Other vehicle identification information and other vehicle transmission information related to another vehicle packet in which an error is detected when an error is detected in the error detection decoding means to be generated and the error detection decoding result for the fourth received information Corresponding to the same other vehicle identification information and other vehicle transmission information identification information as the identification information, the reception information related to the other vehicle packet already received, and the reception information related to the other vehicle packet in which the error is detected, Receiving information combining means for combining based on the second received signal state and generating sixth received information after the combining, the puncture decoding means for the sixth received information Puncture decoding related to the puncture code is performed to generate seventh reception information after puncture decoding, and the error correction decoding means performs error correction decoding related to the error correction code on the seventh reception information. To generate eighth received information after error correction decoding, and the error detection decoding means performs error detection decoding on the error detection code for the eighth received information, and performs error detection decoding The ninth reception information after generation is generated.

  According to the error correction method and the inter-vehicle communication system according to the present invention, high communication quality can be ensured even in a multipath environment.

  Hereinafter, the best mode for carrying out the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same components are denoted by the same reference numerals, and redundant description is omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

(A) 1st Embodiment The inter-vehicle communication system which concerns on the 1st Embodiment of this invention is mounted in each vehicle.

(A-1) Configuration of the First Embodiment FIG. 1 shows the functional configuration of the transmission processing unit of the inter-vehicle communication system according to the first embodiment.

  In the packet communication in the inter-vehicle communication system, there is a function of generating a header part such as a preamble or a unique word or a footer part such as a postamble or an end delimiter and a function for detecting them, but in the first embodiment, Description is omitted.

  In FIG. 1, a transmission data generation unit 1 generates transmission data D1 to be transmitted to another vehicle based on data received from a higher-level application or the like, and transmits this to the error detection coding unit 2.

  The error detection encoding unit 2 generates transmission data D2 obtained by adding an error detection code such as a CRC (cyclic redundancy check) code to the received transmission data D1, and transmits this to the error correction encoding unit 3.

  The error correction encoding unit 3 receives the received transmission in accordance with the parameters received from the communication control parameter determination unit 4, that is, the error correction code parameter D3 for determining the error correction code type, constraint length, coding rate, interleave size, pattern, etc. Transmission data D4 obtained by error-correcting the data D2 into a convolutional code and a turbo code is generated and transmitted to the puncture encoding unit 5.

  The puncture coding unit 5 performs puncture coding on the received transmission data D4 from the error correction coding unit 3 according to the parameter received from the communication control parameter determination unit 4, that is, the puncture code parameter D5 for determining the data thinning pattern. The performed transmission data D6 is generated and transmitted to the own vehicle packet generation unit 6.

  The own vehicle position detection unit 7 detects the position of the own vehicle using a GPS (Global Positioning System) receiver or the like, and based on the detected own vehicle position, own vehicle position data D7, own vehicle position information D8, and While generating the own vehicle position information D9, the own vehicle position data D7 to the own vehicle packet generation unit 6, the own vehicle position information D8 to the propagation environment estimation unit 8, and the own vehicle position information D9 to the vehicle arrangement estimation unit 9, Send each one.

  The own vehicle ID generation unit 10 generates own vehicle ID data D10 unique to each vehicle, and transmits this to the own vehicle packet generation unit 6.

  The packet number generation unit 11 generates different packet number data D11 for each transmission data D1, and transmits this to the host vehicle packet generation unit 6.

  The continuous transmission number generation unit 12 generates continuous transmission number data D13 for each transmission data D1 according to the continuous transmission number parameter D12 received from the communication control parameter determination unit 4, and transmits this to the own vehicle packet generation unit 6. .

  The serial number generation unit 13 generates serial number data D15 for each transmission data D1 according to the continuous transmission number parameter D14 received from the communication control parameter determination unit 4, and transmits it to the own vehicle packet generation unit 6.

  Here, the continuous transmission number is incremented by 1 every time a packet is generated for the same transmission data D1, and the maximum value is equal to the number of continuous transmissions.

  The channel state estimation data generation unit 14 generates channel state estimation data D16 that is a fixed pattern, and transmits this to the host vehicle packet generation unit 6.

  The communication control parameter determination unit 4 includes QoS information D17 received from the QoS determination unit 15, the propagation environment estimation unit 8, the vehicle arrangement estimation unit 9, the communication vehicle number estimation unit 16, the channel status estimation unit 17, and the communication traffic estimation unit 18, respectively. The propagation environment information D18, vehicle arrangement information D19, communication vehicle number information D20, channel status information D21 and communication traffic information D22 are compared with the communication control parameter determination information D23 received from the communication control parameter determination database storage unit 19. The continuous transmission number parameter D12, the continuous transmission number parameter D14, the puncture code parameter D5, and the error correction code parameter D3 are generated.

  Further, the communication control parameter determination unit 4 sends the continuous transmission number parameter D12 to the continuous transmission number generation unit 12, the continuous transmission number parameter D14 to the continuous transmission number generation unit 13, and the puncture code parameter D5 to the puncture encoding unit 5. The error correction code parameter D3 is transmitted to the error correction encoding unit 3 respectively.

  Furthermore, the communication control parameter determination unit 4 generates puncture code parameter data D24 and error correction code parameter data D25, and transmits them to the own vehicle packet generation unit 6. The puncture code parameter data D24 may be the same or different for all packets.

  The communication control parameter determination database storage unit 19 includes a continuous transmission number parameter D14, a puncture code parameter D5 and an error correction code parameter D3, QoS information D17, propagation environment information D18, vehicle arrangement information D19, communication vehicle number information D20, channel The communication control parameter determination information D23 representing a correspondence table (table) between the status information D21 and the communication traffic information D22 is saved, and the communication control parameter determination information D23 is transmitted to the communication control parameter determination unit 4.

  The QoS determination unit 15 includes QoS (Quality of Service: service quality management) information D17 (requested bit error rate, packet error rate, communication delay, communication area) that is information related to communication quality required for each transmission data D1 from the assumed application. And the like are transmitted to the communication control parameter determination unit 4.

  The propagation environment estimation unit 8 calculates the road shape and building in the communication area of the host vehicle from the map information D26 received from the map database storage unit 21 and the vehicle position information D8 received from the host vehicle position detection unit 7. Based on the arrangement or the like, the propagation environment in the communication area, that is, whether the environment has many multipaths, whether the environment has many non-line-of-sight ranges, or the like is estimated, and propagation environment information D18 indicating the estimation result Is transmitted to the communication control parameter determination unit 4.

  The vehicle arrangement estimating unit 9 is based on the map information D27, the own vehicle position information D9, and the other vehicle position information D28 received from the map database storage unit 21, the own vehicle position detecting unit 7 and the other vehicle position estimating unit 22, respectively. The relative positional relationship between the vehicle and the other vehicle and the relationship as to whether the vehicle is within the line of sight are estimated, and the vehicle arrangement information D19 indicating the estimated result is transmitted to the communication control parameter determination unit 4.

  The map database storage unit 21 stores a database of road shapes, building arrangements, and the like, and transmits map information D26 and map information D27 based on these information to the propagation environment estimation unit 8 and the vehicle arrangement estimation unit 9, respectively. .

  The reception signal amplitude estimation data generation unit 23 generates reception signal amplitude estimation data D29, which is a fixed pattern, and transmits this to the host vehicle packet generation unit 6.

  The own vehicle packet generation unit 6 includes a reception signal amplitude estimation data generation unit 23, an own vehicle ID generation unit 10, a packet number generation unit 11, a continuous transmission number generation unit 12, a continuous transmission number generation unit 13, and an own vehicle position detection unit. 7. Received signal amplitude estimation data D29, own vehicle ID data D10, packet number data D11, continuous transmission count data D13, continuous transmission number data D15 received from the channel state estimation data generation unit 14 and the puncture encoding unit 5, respectively. Based on the own vehicle position data D7, the channel condition estimation data D16 and the transmission data D6, and the puncture code parameter data D24 and the error correction code parameter data D25 received from the communication control parameter determination unit 4, the own vehicle packet D30 is generated. Then, this is transmitted to the packet transmission unit 24.

  The packet transmission unit 24 performs modulation processing or the like on the host vehicle packet D30 received from the host vehicle packet generation unit 6 to generate a transmission packet D31, and transmits this to another vehicle via the transmission antenna 25.

  Here, an example of the format of the own vehicle packet D30 according to the first embodiment is shown in FIG. However, in this example, the header part and the footer part are omitted.

In the own vehicle packet D30, data other than that shown in the format example shown in FIG. 3 may be added, and the order of the data in the packet may be different. Further, the received signal amplitude estimation data D29 and the channel condition estimation data D16 do not have to be one block each, and may be divided and exist at a plurality of locations in the packet.
FIG. 2 shows a functional configuration of the reception processing unit of the inter-vehicle communication system according to the first embodiment.

  The packet receiving unit 26 receives the received packet D32 transmitted from the other vehicle via the receiving antenna 27, performs a modulation process or the like on the received packet D32, and generates another vehicle packet D33. It transmits to the packet decomposing unit 28.

  However, the amplitude of each symbol (signal) of the other vehicle packet D33 is assumed to be an analog or analog value that can be subjected to soft decision decoding converted to a discrete output.

  As an example, when the demodulation method is a delay detection method, the delay detection process is performed using two adjacent symbols in the received packet D32, but the hard decision is not performed on the analog value output by the delay detection process, The other vehicle packet D33 is the analog output or the analog output quantized to a discrete value.

  The other vehicle packet decomposing unit 28 receives the received signal amplitude estimation data D34, the other vehicle ID data D35, the packet number data D36, from the received other vehicle packet D33 from the received packet receiving unit 26 according to the packet format shown in FIG. Continuous transmission number data D37, continuous transmission number data D38, other vehicle position data D39, channel condition estimation data D40, puncture code parameter data D41, error correction code parameter data D42 and reception data D43 are extracted, and reception signal amplitude estimation is performed respectively. Unit 29, other vehicle ID detection unit 30, packet number detection unit 31, continuous transmission number detection unit 32, continuous transmission number detection unit 33, other vehicle position estimation unit 22, channel situation estimation unit 17, puncture code parameter detection unit 34, Error correction code parameter detection unit 35 and received data level adjustment And transmits it to the part 36.

  Further, every time the other vehicle packet decomposing unit 28 receives the other vehicle packet D33 from the packet receiving unit 26, the other vehicle packet decomposing unit 28 generates communication traffic estimation information D44 indicating the size of the other vehicle packet D33, and sends this to the communication traffic estimating unit 18. Send.

  The reception signal amplitude estimation unit 29 receives the reception signal related to each symbol of the reception signal amplitude estimation data D34 based on the analog value or the discrete value of each symbol of the reception signal amplitude estimation data D34 received from the other vehicle packet decomposition unit 28. The amplitude level D45 is estimated.

  Specifically, for example, as shown in FIG. 3, when the received signal amplitude estimation data D34 is one block composed of a plurality of symbols, the received signal amplitude of each symbol of the received signal amplitude estimation data D34 is calculated. The average received signal amplitude in one block is calculated, and the calculated average received signal amplitude is assumed to be equal to the received signal amplitude level D45 of all symbols in the received data D43.

  On the other hand, when the received signal amplitude estimation data D34 is composed of two blocks composed of a plurality of symbols and is added before and after the received data D43, as shown in FIG. The average received signal amplitude for each data D34 is calculated, and the received data amplitude level D45 of each symbol is estimated in the received data D43 as monotonically increasing or decreasing between the amplitude levels of these average received signal amplitudes.

  Then, the received signal amplitude estimating unit 29 transmits the estimated received signal amplitude level D45 to the received data level adjusting unit 36.

  The other vehicle ID detection unit 30 detects the other vehicle ID by making a hard decision on the other vehicle ID data D35 received from the other vehicle packet decomposition unit 28, and receives the other vehicle ID information D46 and the other vehicle ID information D47, respectively. The data is transmitted to the combining unit 37 and the communication vehicle number estimating unit 16.

  The packet number detecting unit 31 detects the packet number information D48 by making a hard decision on the packet number data D36 received from the other vehicle packet decomposing unit 28, and transmits this to the received data combining unit 37.

  The continuous transmission number detecting unit 32 detects the continuous transmission number information D49 by making a hard decision on the continuous transmission number data D37 received from the other vehicle packet decomposing unit 28, and transmits this to the received data combining unit 37.

  The serial number detection unit 33 detects the serial number information D50 by making a hard decision on the serial number data D38 received from the other vehicle packet decomposition unit 28, and transmits this to the reception data synthesis unit 37.

  The puncture code parameter detection unit 34 detects the puncture code parameter D51 by making a hard decision on the puncture code parameter data D41 received from the other vehicle packet decomposition unit 28, and transmits this to the reception data synthesis unit 37.

  The error correction code parameter detection unit 35 detects the error correction code parameter D52 by making a hard decision on the error correction code parameter data D42 received from the other vehicle packet decomposition unit 28, and transmits this to the reception data synthesis unit 37.

  The reception data level adjustment unit 36 adjusts the signal amplitude level of each symbol of the reception data D43 received from the other vehicle packet decomposition unit 28 based on the reception signal amplitude level D45 received from the reception signal amplitude estimation unit 29. D53 is generated.

  For example, as shown in FIG. 5A, one symbol in the reception data D43 is expressed as s = a * exp (j * θ) (that is, the reception signal amplitude level is a), and the symbol When the value of the received signal amplitude level D45 is A, the adjusted symbol is S ′ = (a / A) * exp (j * θ) as shown in FIG.

  Further, the reception data level adjustment unit 36 transmits the adjusted reception data D53 and reception signal amplitude level D54 to the reception data synthesis unit 37.

  Here, it is assumed that the reception signal amplitude level D54 is equal to the reception signal amplitude level D45 or equal to the reception signal amplitude level of each symbol calculated based on the reception data D43.

  The reception data combining unit 37 stores the reception data D53 received from the reception data level adjustment unit 36, and also includes another vehicle ID detection unit 30, a packet number detection unit 31, and a continuous transmission number detection unit 32 corresponding to each reception data D53. The other vehicle ID information D46, packet number information D48, continuous transmission count information D49, continuous transmission number information D50, and puncture code parameter D51 received from the continuous transmission number detection unit 33 and the puncture code parameter detection unit 34 are stored together. .

  The reception data combining unit 37 transmits the reception data D55 equal to the reception data D53 and the puncture code parameter D56 equal to the puncture code parameter D51 to the puncture decoding unit 38.

  The puncture decoding unit 38 performs puncture decoding on the received data D55 received from the received data combining unit 37 based on the puncture code parameter D56 (for example, data before puncture encoding by adding a signal amplitude 0 to a thinned symbol) The received data D57 after puncture decoding is transmitted to the error correction decoding unit 39.

  The error correction decoding unit 39 performs error correction decoding on the received data D57 received from the puncture decoding unit 38, based on the error correction code parameter D52 received from the error correction code parameter detection unit 35. That is, Viterbi decoding, turbo decoding, etc. are performed using received data D57, which is soft decision data.

  Further, the error correction decoding unit 39 transmits the received data D58 after error correction decoding to the error detection decoding unit 40.

  The error detection / decoding unit 40 detects an error such as a CRC code using the reception data D58 received from the error correction decoding unit 39. When no error is detected, the reception data D59 after error detection is transmitted to the reception data determination unit 41, and the error detection result information D60 is transmitted to the reception data synthesis unit 37 as “no error”. On the other hand, when an error is detected, the error detection result information D60 is transmitted to the reception data combining unit 37 as “error”.

  Then, the received data combining unit 37 has the error detection result information D60 received from the error detection / decoding unit 40 of [with error] and the other vehicle ID information D46 that is the same as the other vehicle packet D33 in which the error is detected, and When a plurality of received data D53 related to the other vehicle packet D33 corresponding to the packet number information D48 are received, a plurality of punctures corresponding to the received data D53 related to the same other vehicle ID information D46 and packet number information D48 are received. The code parameter D51 is combined and the plurality of received data D53 are combined.

  The plurality of received data D53 are the same as the received data D53 related to the other vehicle packet D33 in which the error is detected, the other vehicle ID information D46 and the packet number information D48 in the other vehicle packet D33 in which the error is detected. It includes reception data D53 related to one or more other vehicle packets D33 corresponding to the vehicle ID information D46 and the packet number information D48.

  Here, an example of a method of synthesizing the puncture code parameter D51 is shown in FIG.

  As shown in FIG. 6, three pieces of received data D53 corresponding to the same other vehicle ID information D46 and packet number information D48 are received, and the puncture patterns corresponding to the puncture code parameters D51 are 1, 4 and 4, respectively. 5, 8, 9, 12, 13, 16, ... (see Fig. 6 (a)), 1, 3, 5, 7, 9, 11, 13, 15, ... (see Fig. 6 (b)), And 1, 2, 5, 6, 9, 10, 13, 14,... (See FIG. 6 (c)), 1, 5, 9, 13, The pattern (see FIG. 6D) is a puncture pattern after synthesis.

  Next, an example of a method for synthesizing the reception data D53 will be described.

For a predetermined symbol in the received data D53, there are N number of received signals that are not punctured (decimated), and each received signal is s (n) = a (n) * exp (j * θ (n)) and the received signal amplitude level is given by A (n) (n = 1, 2,..., N), the synthesized received signal calculates the following equation (1) Is required.

  By calculating the above equation 1 for each symbol of the reception data D53 (by combining the reception signals), the combined reception data can be obtained.

  In the synthesis method based on the calculation of Equation 1, a weight proportional to the received signal amplitude level is added, but another weighting method (for example, proportional to the square of the received signal amplitude level) may be used.

  The reception data combining unit 37 that has performed the combining process in this way transmits the combined reception data D61 and the combined puncture code parameter D62 to the puncture decoding unit 38.

  The puncture decoding unit 38 punctures the reception data D61 received from the reception data synthesis unit 37 based on the puncture code parameter D62, and the reception data D63 after puncture decoding to the error correction decoding unit 39. Send.

  The error correction decoding unit 39 uses the reception data D63 received from the puncture decoding unit 38 and performs error correction decoding based on the error correction code parameter D52 received from the error correction code parameter detection unit 35. That is, Viterbi decoding, turbo decoding, etc. are performed using received data D63 which is soft decision data.

  Further, the error correction decoding unit 39 transmits the received data D64 after error correction decoding to the error detection decoding unit 40.

  The error detection decoding unit 40 performs error detection decoding such as a CRC code using the reception data D64 received from the error correction decoding unit 39.

  When no error is detected, the received data D65 after error detection is transmitted to the received data determining unit 41, and the error detection result information D66 is transmitted to the received data combining unit 37 as [no error]. On the other hand, if an error is detected, the error detection result information D66 is transmitted to the received data combining unit 37 as [error present].

  The combination of the reception data D53 and the puncture code parameter D51 described above is repeated as long as the error detection result information D60 is [with error]. However, after synthesizing the reception data D53 when the continuous transmission number information D49 and the continuous transmission number information D50 are equal, the reception data D53 related to the same other vehicle ID information D46 and the packet number information D48 is thereafter received. Therefore, the reception data combining unit 37 receives the reception data D53, reception signal amplitude level D54, other vehicle ID information D46, packet number information D48, continuous transmission related to the same other vehicle ID information D46 and packet number information D48. The process of storing and combining the number-of-times information D49, the serial number information D50, and the puncture code parameter D51 ends.

  In addition, the reception data combining unit 37, after having received a predetermined time from the time when the first reception data D53 related to the same other vehicle ID information D46 and packet number information D48 has been received, The reception data D53 related to the same other vehicle ID information D46 and the packet number information D48 is assumed to be low in probability of reception, and the processing for storing and combining the reception data D53 and the like is ended as described above.

  By the way, when the error detection result information D60 or the error detection result information D66 received from the error detection / decoding unit 40 is [no error], the received data combining unit 37 is the other vehicle ID information corresponding to the error detection result information D60. D67 (equal to other vehicle ID information D46) or other vehicle ID information D68 (equal to other vehicle ID information D46) corresponding to the error detection result information D66 is transmitted to the reception data determining unit 41.

  The reception data determination unit 41 corresponds to the reception data D59 or reception data D65 received from the error detection decoding unit 40, and the other vehicle ID information D67 or reception data D65 corresponding to the reception data D59 received from the reception data synthesis unit 37. The other vehicle ID information D68 is transmitted to the upper application or the like.

  The communication vehicle number estimation unit 16 determines whether the communication vehicle number is within the communication area of the host vehicle from the type of the other vehicle ID information D47 received from the other vehicle ID detection unit 30 within a predetermined time (for example, the data update cycle of each vehicle). The communication vehicle number information D20 indicating the estimated number of communication vehicles is transmitted to the communication control parameter determination unit 4.

  The channel state estimation unit 17 determines whether the host vehicle and the other vehicle are based on the channel state estimation data D40 received from the other vehicle packet decomposition unit 28 within a predetermined time (for example, the data update period of each vehicle). Estimate the channel conditions during.

  For example, the channel condition estimation data D40 is hard-decided, and the bit error rate is calculated by comparing the result of this hard-decision with predetermined fixed data. The channel status is expressed by the error rate. Alternatively, the received signal amplitude or the received power is calculated based on the channel state estimation data D40, and the channel is represented by the minimum, maximum or average received signal amplitude or received power within the fixed time.

  Further, the channel status estimation unit 17 transmits channel status information D21 indicating the channel status estimated as described above to the communication control parameter determination unit 4.

  The communication traffic estimation unit 18 estimates the communication traffic based on the communication traffic estimation information D44 received from the other vehicle packet decomposition unit 28 within a predetermined time (for example, the data update period of each vehicle), Communication traffic information D22 indicating the estimated communication traffic is transmitted to the communication control parameter determination unit 4.

  The other vehicle position estimating unit 22 makes a hard decision on the other vehicle position data D39 received from the other vehicle packet decomposing unit 28 within a predetermined time (for example, the data update period of each vehicle), and makes this hard decision. Based on the result, the position of the other vehicle in the communication area of the own vehicle is estimated, and further, the other vehicle position information D28 indicating the estimated position of the other vehicle is transmitted to the vehicle arrangement estimating unit 9.

  In the first embodiment, the vehicle position data is transmitted separately from the transmission data. However, if the transmission data includes data representing the vehicle position, the vehicle position data is included in the transmission data. It may be used instead of data.

  In the first embodiment, the channel situation estimation data and the received signal amplitude estimation data are separately added to the own vehicle packet. However, the channel situation estimation data and the received signal amplitude estimation data are the same. In other words, any one of the channel status estimation data and the received signal amplitude estimation data may be added to the vehicle packet.

  In the first embodiment, the channel state estimation data and the received signal amplitude estimation data are added to the own vehicle packet separately from the transmission data, the header part, and the footer part. Part or footer part may be used in place of the channel state estimation data and the received signal amplitude data. That is, the data of the channel state estimation data and the received signal amplitude data are not added to the own vehicle packet, and the data of the header part or footer part such as a unique word may be used instead of these data. Further, not only the header part or the footer part but also the transmission data part may be used for the channel state estimation data and the received signal amplitude estimation data.

  In the first embodiment, the puncture code parameter data is added to the host vehicle packet. However, if the puncture code parameter and the serial number have a one-to-one correspondence, The transmission number data may be used instead of the puncture code parameter data. Further, when the puncture code parameter is the same for all packets, the puncture code parameter may not be added to the own vehicle packet.

  In the first embodiment, the error correction code parameter data is added to the own vehicle packet. However, if the error correction code using all the packets is the same, the error correction code parameter data is sent to the own vehicle. It does not have to be added to the packet.

  In the first embodiment, continuous transmission count data is added to the own vehicle packet. However, if the continuous transmission count is the same for all packets, the continuous transmission count data is added to the own vehicle packet. You don't have to.

  Moreover, in 1st Embodiment, the other vehicle ID detection part 30, the packet number detection part 31, the continuous transmission number detection part 32, the continuous transmission number detection part 33, the channel condition estimation part 17, the other vehicle position estimation part 22, and communication The hard decision processing of the other vehicle packet decomposing unit 28 for traffic estimation is made separate, but the common hard decision unit performs hard decision processing instead of the hard decision processing by the above components. You may do it. In addition, the packet reception unit 26 may perform the hard decision process by each of the above components.

  In the first embodiment, when each communication control parameter is determined by the communication control parameter determination unit 4, QoS information D17, propagation environment information D18, vehicle arrangement information D19, communication vehicle number information D20, channel status information D21, and communication Although all of the traffic information D22 is used, the communication control parameter may be determined based on some of the information.

  Furthermore, in the first embodiment, only the estimation and level adjustment of the received signal amplitude level, that is, the amplitude-only propagation path estimation and equalization are used. However, the propagation path estimation and the like for both amplitude and phase are used. It is also possible to use a conversion.

(A-2) Operation of the First Embodiment Next, communication processing of the inter-vehicle communication system according to the first embodiment will be described.

  In the packet communication related to the communication by the inter-vehicle communication system, a header part such as a preamble or a unique word or a footer part such as a postamble or an end delimiter is generated and detected. In the first embodiment, The description is omitted.

  First, transmission processing of the inter-vehicle communication system will be described with reference to FIG. FIG. 7 is a flowchart showing the processing procedure of the transmission processing.

  In the transmission processing unit of each vehicle, the transmission data generation unit 1 generates transmission data D1 and transmits it to the error detection encoding unit 2 (step S101).

  The error detection encoding unit 2 generates transmission data D2 obtained by adding an error detection code such as CRC encoding to the received transmission data D1, and transmits this to the error correction encoding unit 3 (step S102).

  The error correction coding unit 3 generates an error in the received transmission data D2 according to the error correction code parameter D3 (error correction code type, constraint length, coding rate, interleave size, pattern, etc.) received from the communication control parameter determination unit 4 The transmission data D4 subjected to the correction encoding is generated and transmitted to the puncture encoding unit 5 (step S103).

  The puncture encoding unit 5 generates transmission data D6 obtained by performing puncture encoding on the received transmission data D4 according to the puncture code parameter D5 received from the communication control parameter determination unit 4, and supplies this to the own vehicle packet generation unit 6. Transmit (step S104).

  The continuous transmission number generator 13 generates a continuous transmission number = 1 for the transmission data D1 (transmission data corresponding to the transmission data D6), and transmits this to the host vehicle packet generator 6 (step S105).

  The own vehicle packet generation unit 6 receives the received signal amplitude estimation data D29 received from the received signal amplitude estimation data generation unit 23, the own vehicle ID data D10 received from the own vehicle ID generation unit 10, and the packet number generation unit 11. Packet number data D11, continuous transmission number data D13 received from the continuous transmission number generation unit 12, continuous transmission number data D15 received from the continuous transmission number generation unit 13, and own vehicle position data D7 received from the own vehicle position detection unit 7. Channel condition estimation data D16 received from the channel condition estimation data generation unit 14, puncture code parameter data D24 and error correction code parameter data D25 received from the communication control parameter determination unit 4, and received from the puncture encoding unit 5 Using the transmission data D6, the packet format as shown in FIG. Thus generating a vehicle packet D30, and transmits to the packet transmission unit 24 (step S106).

  And the packet transmission part 24 performs a modulation process etc. on the transmission data D6 of the received own vehicle packet D30, produces | generates the transmission packet D31, and transmits this to another vehicle via the transmission antenna 25 (step S107).

  The transmission processing unit (the own vehicle packet generation unit 6) transmits the transmission packet D31, that is, the value of the continuous number data D15 of the generated own vehicle packet D30, that is, the continuous transmission received from the continuous number generation unit 13. It is determined whether or not the value of the number data D15 is equal to the value of the continuous transmission number data D13 received from the continuous transmission number generation unit 12 (step S108).

  If it is determined in step S108 that the value of the continuous transmission number data D15 is smaller than the value of the continuous transmission number data D13, the continuous transmission number generation unit 13 transmits the transmission data D1 (transmission data corresponding to the transmission data D6). Then, “continuous transmission number = continuous transmission number + 1” is calculated (generated), and this is transmitted to the vehicle packet generation unit 6 (step S109). After step S109 is completed, the process returns to step S106.

  If it is determined in step S108 that the value of the continuous transmission number data D15 is equal to the value of the continuous transmission count data D13, this transmission processing is terminated.

  That is, each vehicle repeats the above-described transmission operation as long as the value of the continuous number data D15 of the transmitted transmission packet D31 is smaller than the value of the continuous number of times data D13.

  Next, reception processing of the inter-vehicle communication system will be described with reference to FIG. FIG. 8 is a flowchart showing the processing procedure of the reception processing.

  In the reception processing unit of each vehicle, the packet reception unit 26 receives the reception packet D32 via the reception antenna 27, demodulates the reception packet D32, and generates another vehicle packet D33 (step S201).

  Here, the amplitude of each symbol of the other vehicle packet D33 is assumed to be an analog value that can be subjected to soft decision decoding, or an analog value that is converted to a discrete output.

  The packet receiving unit 26 transmits the generated other vehicle packet D33 to the other vehicle packet decomposing unit 28.

  The other vehicle packet disassembling unit 28 receives the received other vehicle packet D33 in accordance with the packet format as shown in FIG. 3, and receives signal amplitude estimation data D34, other vehicle ID data D35, packet number data D36, and continuous transmission number data D37. The transmission number data D38, the other vehicle position data D39, the channel condition estimation data D40, the puncture code parameter data D41, the error correction code parameter data D42, and the reception data D43 are decomposed (step S202).

  Further, the other vehicle packet decomposing unit 28 receives the received signal amplitude estimation data D34, the other vehicle ID data D35, the packet number data D36, the continuous number of times data D37, the continuous number data D38, the other vehicle position data D39, the channel The situation estimation data D40, the puncture code parameter data D41, the error correction code parameter data D42, and the reception data D43 are respectively received as the reception signal amplitude estimation unit 29, the other vehicle ID detection unit 30, the packet number detection unit 31, and the continuous transmission number detection unit 32. The serial number detection unit 33, the other vehicle position estimation unit 22, the channel state estimation unit 17, the puncture code parameter detection unit 34, the error correction code parameter detection unit 35, and the reception data level adjustment unit 36 are transmitted.

  The reception signal amplitude estimation unit 29 uses the received reception signal amplitude estimation data D34 to calculate the reception signal amplitude width at the time of reception of the reception signal amplitude estimation data D34, and the value of the calculated reception signal amplitude width The received signal amplitude level D45 at the time of reception of the received data D43 is estimated based on (step S203), and the estimated received signal amplitude level D45 is transmitted to the received data level adjustment unit 36.

  The reception data level adjustment unit 36 adjusts the signal amplitude level of the received reception data D43 based on the received reception signal amplitude level D45 (step S204), and receives the adjusted reception data D53 together with the reception signal amplitude level D54. It transmits to the data composition unit 37.

  The received data combining unit 37 punctures the received puncture code parameter D56 equal to the puncture code parameter D51 received from the puncture code parameter detection unit 34 and received data D55 equal to the received data D53 received from the received data level adjustment unit 36. 38.

  The puncture decoding unit 38 puncture-decodes the received reception data D55 based on the received puncture code parameter D56 (step S205), and transmits the reception data D57 after puncture decoding to the error correction decoding unit 39.

  The error correction decoding unit 39 performs error correction decoding on the reception data D57 received from the puncture decoding unit 38 based on the error correction code parameter D52 received from the error correction code parameter detection unit 35 (step S206), and performs error correction. The decoded reception data D58 is transmitted to the error detection decoding unit 40.

  The error detection decoding unit 40 performs error detection decoding on the received received data D58 using a CRC code or the like (step S207), generates error detection result information D60 indicating the error detection result, and stores the error detection result information D60. The data is transmitted to the reception data combining unit 37, and it is determined whether or not the error detection result information D60 is [with error] (step S208).

  If the error detection decoding unit 40 determines in step S2078 that the error detection result information D60 is [no error], the error detection decoding unit 40 transmits the reception data D59 after error detection decoding to the reception data determination unit 41.

  On the other hand, when the received error detection result information D60 is “no error”, the reception data combining unit 37 transmits the other vehicle ID information D67 for the reception data D59 to the reception data determination unit 41.

  The reception data determining unit 41 determines that the reception data D59 from the error detection decoding unit 40 is normal reception data (step S209), and the other vehicle ID information D67 from the reception data D59 and the reception data combining unit 37. Is sent to the host application or the like.

  Then, the reception processing unit ends this reception processing after step S209 is completed.

  If the error detection / decoding unit 40 determines that the error detection result information D60 is “with error” in step S208, the error detection result information D60 meaning “with error” is received from the error detection / decoding unit 40. Since the data has been transmitted to the data synthesis unit 37, the reception data synthesis unit 37 executes a process corresponding to the case where the error detection result information D60 is “with error”.

  That is, when the received error detection result information D60 is [with error], the received data combining unit 37 uses the other vehicle ID information D46 and the other vehicle related to the packet number information D48 that are the same as the other vehicle packet in which the error is detected. It is determined whether a packet has already been received (step S210).

  In step S210, the received data combining unit 37, which has determined that the other vehicle packet related to the other vehicle ID information D46 and the packet number information D48 that are the same as the other vehicle packet in which the error is detected, has already been received, A plurality of reception data D53 for other vehicle packets corresponding to the same other vehicle ID information D46 and packet number information D48 are combined to generate reception data D61, and a plurality of puncture code parameters D51 are combined to generate a puncture code parameter D62. Is generated (step S211).

  That is, the received data combining unit 37 receives the other vehicle ID information D46 and the other vehicle ID related to the packet number information D48 that are the same as the other vehicle packet in which the received error detection result information D60 is [with error] and the error is detected. When a plurality of reception data D53 for the packet is received, a plurality of reception data D53 for the other vehicle packet corresponding to the other vehicle ID information D46 and the packet number information D48 that are the same as the other vehicle packet are synthesized to receive data D61. And a plurality of puncture code parameters D51 are combined to generate a puncture code parameter D62.

  The reception data combining unit 37 that has finished step S211 transmits the combined reception data D61 and the combined puncture code parameter D62 to the puncture decoding unit 38.

  The puncture decoding unit 38 puncture-decodes the received reception data D61 based on the received puncture code parameter D62 (step S212), and transmits the reception data D63 after puncture decoding to the error correction decoding unit 39.

  The error correction decoding unit 39 performs error correction decoding on the received data D63 received from the puncture decoding unit 38 based on the error correction code parameter D52 received from the error correction code parameter detection unit 35 (step S213), and performs error correction. The decoded reception data D64 is transmitted to the error detection decoding unit 40.

  The error detection decoding unit 40 performs error detection decoding on the received received data D64 with a CRC code or the like (step S214), generates error detection result information D66 indicating the error detection result, and stores the error detection result information D66. The data is transmitted to the reception data combining unit 37, and it is determined whether or not the error detection result information D66 is [with error] (step S215).

  If the error detection decoding unit 40 determines in step S215 that the error detection result information D66 is [no error], the error detection decoding unit 40 transmits the reception data D65 after error detection decoding to the reception data determination unit 41.

  On the other hand, when the received error detection result information D66 is [No error], the reception data combining unit 37 transmits the other vehicle ID information D68 for the reception data D65 to the reception data determination unit 41.

  Then, the reception data determination unit 41 determines that the reception data D65 from the error detection decoding unit 40 is normal reception data (step S209), and the other vehicle ID from the reception data D65 and the reception data combining unit 37. Information D68 is transmitted to the upper application or the like.

  By the way, when the received data combining unit 37 determines in step S210 that the other vehicle packet related to the other vehicle ID information D46 and the packet number information D48 that are the same as the other vehicle packet in which the error is detected has not been received. Determines whether or not the value of the serial number information D50 related to the other vehicle packet corresponding to the received error detection result information D60 or the error detection result information D66 is equal to the value of the continuous transmission count information D49 (step S216). .

  If the received data combining unit 37 determines in step S215 that the error detection result information D66 is “error”, the value of the serial number information D50 related to the other vehicle packet corresponding to the received detection result information D66. It is determined whether or not the value of the continuous transmission count information D49 is equal (step S216).

  In other words, the received data combining unit 37 is related to the other vehicle ID information D46 and the packet number information D48 that are the same as the other vehicle packet in which the received error detection result information D60 is [with error] and the error is detected. When no other received data D53 for another vehicle packet is received or when the received error detection result information D66 is [with error], it corresponds to the received error detection result information D60 or error detection result information D66. The value of the continuous number information D50 related to the other vehicle packet is compared with the value of the continuous number of times information D49.

  In step S216, the reception data combining unit 37, which has determined that the value of the continuous transmission number information D50 is smaller than the value of the continuous transmission number information D49, receives the reception data D53 (related to the same other vehicle ID information D46 and packet number information D48 It is determined whether or not a predetermined time has passed since the reception of the first corresponding reception data D65) (step S217).

  If it is determined in step S217 that the predetermined time has not elapsed, the process returns to step S201. Thus, the reception processing unit receives other vehicle packets having the same other vehicle ID and packet number until the predetermined time elapses.

  Then, when the reception processing unit receives another vehicle packet having the same other vehicle ID and packet number before the predetermined time elapses, the reception processing unit repeats the above-described reception processing.

  On the other hand, if it is determined in step S217 that a certain time has elapsed, that is, if another vehicle packet having the same other vehicle ID and packet number is not received even after the certain time has elapsed, a reception processing unit Is determined to be a packet error (step S218), and this reception process is terminated.

  If it is determined in step S216 that the value of the continuous transmission number information D50 is equal to the value of the continuous transmission number information D49, the reception processing unit determines that there is a packet error (step S218), and ends this reception processing.

  Next, communication control parameter determination processing of the inter-vehicle communication system will be described with reference to FIG. FIG. 9 is a flowchart showing a processing procedure of the communication control parameter determination processing.

  The communication control parameter determination unit 4 includes QoS information output from the QoS determination unit 15, the propagation environment estimation unit 8, the vehicle arrangement estimation unit 9, the communication vehicle number estimation unit 16, the channel status estimation unit 17, and the communication traffic estimation unit 18. When D17, propagation environment information D18, vehicle arrangement information D19, communication vehicle number information D20, channel status information D21 and communication traffic information D22 are received (steps S301 to S306), these pieces of information are stored in a communication control parameter determination database. By comparing with the communication control parameter determination information D23 received from the unit 19, the communication control parameters, that is, the continuous transmission number parameter, the puncture code parameter, and the error correction code parameter are determined (step S307).

  Next, the communication control parameter determination unit 4 sends the continuous transmission number parameter D12, the continuous transmission number parameter D14, the puncture code parameter D5, and the error correction code parameter D3 determined in this way, to the continuous transmission number generation unit 12, While transmitting to the number generation part 13, the puncture encoding part 5, and the error correction encoding part 3, the puncture code parameter data D24 and the error correction code parameter data D25 are transmitted to the own vehicle packet generation part 6.

  The communication control parameter determination unit 4 executes the above-described communication control parameter determination process every time a predetermined time (for example, a transmission data update cycle) elapses.

(A-3) Effects of First Embodiment As described above, according to the first embodiment, the following effects (1) to (5) can be obtained.

  (1) The packet error rate can be improved by using the continuous transmission method.

  (2) By determining the QoS in each application and estimating the propagation environment, vehicle arrangement, and channel status, the optimum number of consecutive transmissions, error correction code, and the like in a multipath environment for other vehicles in the communication area of the assumed application Since the puncture code can be used, the communication quality of the bit error rate and the packet error rate can be improved.

  (3) By estimating the number of communication vehicles and communication traffic in the communication area, it is possible to use the optimum number of continuous transmissions, error correction codes, and puncture codes, so packet collision when the number of communication vehicles increases Can be reduced.

  (4) It is possible to ensure high communication quality even in a multipath environment by estimating the received signal amplitude and adjusting the received data level, or estimating the received signal amplitude and phase and adjusting the received data level and phase. it can.

  (5) By combining received data (and combining puncture code parameters), it is possible to successfully receive a packet that is an error in a single packet. That is, with respect to symbols transmitted in a plurality of packets, the accuracy of signal amplitude and phase can be improved, and the influence of deterioration of communication quality due to puncturing can be suppressed.

(B) Other Embodiments In the above embodiment, the modulation / demodulation method is not limited. However, if the modulation / demodulation method is a π / 4-QPSK method, the received signal, the received signal amplitude, and the channel state estimation are performed. The received signal amplitude and received power at that time may be set as follows.

  When the modulation / demodulation method is the π / 4-QPSK method, delay detection is performed on the received signal r (n) = d (n) * exp (j * φ (n)) from the radio channel, and the received signal s (n ) Is established, the following relational expression (1) is established, and the received signal s (n) can be defined by the expression (2).

s (n) = a (n) * exp (j * θ (n))
= R (n) * r (n-1)
= D (n) * exp (j * φ (n)) * d (n−1) * exp (j * φ (n−1))
= D (n) * d (n-1) * exp (j * ([phi] (n)-[phi] (n-1)) (1)
a (n) = d (n) * d (n-1)
θ (n) = φ (n) −φ (n−1) (2)
Although related to the above contents, when a PSK system such as a π / 4-QPSK (delayed detection) system is used, the received signal is passed through an AGC, a limiter amplifier, or the like. At this time, there is no information on the received signal amplitude a (n) (or d (n)). In this case, the received signal amplitude value may be calculated based on the RSSI value of the received signal. good.

  Furthermore, when the PSK method such as the π / 4-QPSK (delay detection) method is used and the received signal is passed through the AGC or the limiter amplifier, the information on the received signal amplitude is lost. Based on the value, the received signal amplitude and the received power may be calculated to estimate the channel condition.

  Although the case where the continuous transmission method is used has been described in the above embodiment, the present invention can also be applied to the case where the retransmission method is used.

  The present invention relates to a system that employs a vehicle-to-vehicle communication system that performs vehicle-to-vehicle communication for exchanging information with each other by wireless communication, such as a travel support system that supports the traveling of a vehicle, and information about the risk of a collision with another vehicle. It can be applied to right and left turn support systems provided to drivers.

It is a functional block diagram which shows the function structure of the transmission process part of the communication system between vehicles which concerns on 1st Embodiment. It is a functional block diagram which shows the function structure of the reception process part of the communication system between vehicles which concerns on 1st Embodiment. It is a figure which shows an example of the packet format which concerns on 1st Embodiment. It is a figure explaining the estimation method of the received signal level by the received signal amplitude estimation part which concerns on 1st Embodiment. It is a figure explaining the adjustment method of the reception data level by the reception data level adjustment part which concerns on 1st Embodiment. It is a figure explaining an example of the synthetic | combination method of the puncture code parameter which concerns on 1st Embodiment. It is a flowchart which shows the process sequence of the transmission process of the vehicle-to-vehicle communication system which concerns on 1st Embodiment. It is a flowchart which shows the process sequence of the reception process of the vehicle-to-vehicle communication system which concerns on 1st Embodiment. It is a flowchart which shows the process sequence of the communication control parameter determination process of the vehicle-to-vehicle communication system which concerns on 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmission data generation part, 2 ... Error detection encoding part, 3 ... Error correction encoding part, 4 ... Communication control parameter determination part, 5 ... Puncture encoding part, 6 ... Own vehicle packet generation part, 7 ... Own vehicle Position detection unit, 8 ... Propagation environment estimation unit, 9 ... Vehicle arrangement estimation unit, 10 ... Own vehicle ID generation unit, 11 ... packet number generation unit, 12 ... continuous transmission number generation unit, 13 ... continuous transmission number generation unit, 14 ... data generation unit for channel status estimation, 15 ... QoS determination unit, 16 ... communication vehicle number estimation unit, 17 ... channel status estimation unit, 18 ... communication traffic estimation unit, 19 ... communication control parameter determination database storage unit, 21 ... Map database storage unit, 22 ... other vehicle position estimation unit, 23 ... received signal amplitude estimation data generation unit, 24 ... packet transmission unit, 25 ... transmission antenna, 26 ... packet reception unit, 27 ... reception antenna 28 ... Other vehicle packet decomposition unit, 29 ... Received signal amplitude estimation unit, 30 ... Other vehicle ID detection unit, 31 ... Packet number detection unit, 32 ... Continuous transmission number detection unit, 33 ... Continuous transmission number detection unit, 34 ... Puncture Code parameter detection unit, 35 ... error correction code parameter detection unit, 36 ... received data level adjustment unit, 37 ... received data synthesis unit, 38 ... puncture decoding unit, 39 ... error correction decoding unit, 40 ... error detection decoding 41, a received data determining unit.

Claims (18)

A packet receiving step for receiving another vehicle packet that is transmitted from another vehicle and includes received information and information for estimating a received signal level related to estimation of a received signal level of the received information when the received information is received;
A reception signal state estimation step for estimating a reception signal state of a reception signal when receiving reception information included in the other vehicle packet based on the received signal level estimation information included in the received other vehicle packet. When,
A reception information generation step of generating new reception information based on the reception signal state estimated by the reception signal state estimation step and the reception information included in the other vehicle packet;
A puncture decoding step for performing puncture decoding on the puncture code for the new received information;
An error correction decoding step for performing error correction decoding related to an error correction code on a result of the puncture decoding process by the puncture decoding step;
An error detection decoding step for performing error detection decoding related to an error detection code on a result of the error correction decoding process by the error correction decoding step,
An error correction method in inter-vehicle communication, wherein an error correction of a packet of another vehicle received based on a result of an error detection decoding process in the error detection decoding step is performed. When the result of the error detection decoding process by the error detection decoding step has an error, and other vehicle identification information that is the same as the other vehicle packet in which the error is detected and other vehicle packet identification information corresponding to the other vehicle packet identification information. If another vehicle packet has already been received, the reception information related to the other vehicle packet in which the error is detected is combined with the reception information related to the other vehicle packet that has already been received, and the reception after the combination is performed. A reception information combining step for generating information;
Puncture decoding processing by the puncture decoding step, error correction decoding processing by the error correction decoding step, and error detection decoding step for the received information combined by the reception information combining step Perform error detection decoding processing by
2. The error correction method for inter-vehicle communication according to claim 1, wherein error correction is performed on the received packet based on a result of error detection decoding processing in the error detection decoding step. In the case where there is an error as a result of the error detection decoding process in the error detection decoding step, the number of continuous transmissions related to continuous transmission of other vehicle packets in which the error is detected is less than a preset number of times, and When a certain period of time has not elapsed since the other vehicle packet corresponding to the other vehicle packet identification information and the other vehicle packet identification information that are the same as the other vehicle packet in which the error is detected is first received,
Until the predetermined time elapses, the other vehicle identification information and the other vehicle packet corresponding to the other vehicle packet identification information that are continuously transmitted from the other vehicle and in which the error is detected are received. The error correction method in inter-vehicle communication according to claim 2. The other vehicle packet corresponding to the other vehicle information and the other vehicle packet information that are the same as the other vehicle packet in which the error is detected when the result of the error detection decoding process by the error detection decoding step is erroneous. The number of continuous transmissions related to the continuous transmission of other vehicle packets in which the error has been detected is less than a preset number and the same as the other vehicle packet in which the error has been detected. When a certain period of time has not elapsed since the other vehicle packet corresponding to the vehicle identification information and the other vehicle packet identification information was first received,
Until the predetermined time elapses, the other vehicle identification information and the other vehicle packet corresponding to the other vehicle packet identification information that are continuously transmitted from the other vehicle and in which the error is detected are received. The error correction method in inter-vehicle communication according to claim 2. A packet receiving means for receiving another vehicle packet that is transmitted from another vehicle and includes received information and information for estimating a received signal level related to estimation of a received signal level of the received information when the received information is received;
Received signal state estimating means for estimating the received signal state of the received signal when receiving the received information included in the other vehicle packet based on the received signal level estimation information included in the received other vehicle packet. When,
Reception information generation means for generating new reception information based on the reception signal state estimated by the reception signal state estimation means and the reception information included in the other vehicle packet;
Puncture decoding means for performing puncture decoding related to a puncture code for the new received information;
Error correction decoding means for performing error correction decoding related to an error correction code on a result of puncture decoding processing by the puncture decoding means;
Error detection decoding means for performing error detection decoding related to an error detection code on the result of error correction decoding processing by the error correction decoding means;
An inter-vehicle communication system, wherein an error correction of a received packet is performed based on a result of an error detection decoding process by the error detection decoding means. Processing means for obtaining a first received signal state representing the amplitude of the received signal when receiving the received signal level estimating information based on the received signal level estimating information included in the received other vehicle packet; In addition,
The reception signal state estimation means estimates a second reception signal state of the reception signal when receiving reception information included in the other vehicle packet based on the first reception signal state,
The reception information generation means generates new reception information based on the second reception signal state estimated by the reception signal state estimation means and the reception information included in the other vehicle packet. Item 6. The inter-vehicle communication system according to Item 5.   The processing means is a first receiving unit that represents the amplitude and phase of a received signal when receiving the received signal level estimation information based on the received signal level estimation information included in the received other vehicle packet. The inter-vehicle communication system according to claim 6, wherein a signal state is obtained. When the result of the error detection decoding process by the error detection decoding means has an error, and other vehicle identification information that is the same as the other vehicle packet in which the error is detected and other vehicle packet identification information corresponding to the other vehicle packet identification information When the other vehicle packet has already been received, the reception information related to the other vehicle packet is combined with the reception information related to the other vehicle packet in which the error is detected, and the combined reception information is generated. A reception information combining unit;
By the puncture decoding process by the puncture decoding means, the error correction decoding process by the error correction decoding means, and the error detection decoding means for the received information synthesized by the reception information synthesis means The vehicle-to-vehicle communication system according to any one of claims 5 to 7, wherein an error detection decoding process is performed. In the case where the error detection decoding process by the error detection decoding means has an error, the number of continuous transmissions related to continuous transmission of other vehicle packets in which the error is detected is less than a preset number of times, and When a certain period of time has not elapsed since the other vehicle packet corresponding to the other vehicle packet identification information and the other vehicle packet identification information that are the same as the other vehicle packet in which the error is detected is first received,
Until the predetermined time elapses, the other vehicle identification information and the other vehicle packet corresponding to the other vehicle packet identification information that are continuously transmitted from the other vehicle and in which the error is detected are received. The inter-vehicle communication system according to claim 8. Other vehicle packet corresponding to other vehicle packet identification information and other vehicle packet identification information that are the same as the other vehicle packet in which the error is detected when the result of the error detection decoding process by the error detection decoding means includes an error Is not received, and the number of continuous transmissions related to the continuous transmission of the other vehicle packet in which the error is detected is less than a preset number and the same as the other vehicle packet in which the error is detected. When a certain period of time has not elapsed since the other vehicle packet corresponding to the vehicle identification information and the other vehicle packet identification information was first received,
Until the predetermined time elapses, the other vehicle identification information and the other vehicle packet corresponding to the other vehicle packet identification information that are continuously transmitted from the other vehicle and in which the error is detected are received. The inter-vehicle communication system according to any one of claims 5 to 7. Error detection coding means for performing error detection coding on the error detection code for predetermined transmission information;
Error correction coding means for performing error correction coding related to an error correction code on a result of error out coding processing by the error detection coding means;
Puncture encoding means for performing puncture encoding related to puncture code on the result of error correction encoding processing by the error correction encoding means;
Transmission information to be transmitted as a result of puncture encoding processing by the puncture encoding means, reception signal level estimation information related to estimation of the reception signal level of the transmission information when the transmission information to be transmitted is received, Own vehicle packet generation means for generating own vehicle packet including own vehicle identification information indicating the own vehicle, own vehicle packet identification information indicating a transmission packet to be transmitted, and continuous transmission information related to continuous transmission;
The vehicle-to-vehicle communication system according to any one of claims 5 to 10, further comprising: packet transmission means for transmitting the host vehicle packet to another vehicle at least once. Transmission information generating means for generating first transmission information;
Error detection coding means for adding error detection code to the first transmission information to generate second transmission information;
Error correction coding means for performing error correction coding related to an error correction code on the second transmission information and generating third transmission information after the error correction coding;
Puncture coding means for performing puncture coding related to a puncture code for partially thinning out information in the third transmission information and generating fourth transmission information after puncture coding;
Own vehicle identification information generating means for generating own vehicle identification information;
Own vehicle transmission information identification information generating means for generating own vehicle transmission information identification information related to the first transmission information;
Continuous transmission means for transmitting the packet related to the first transmission information at least once;
A continuous number of times generating means for generating information on the number of times of continuous transmission of the own vehicle,
A serial number generating means for generating own vehicle serial number information relating to the serial number;
First reception signal state estimation information generation means for generating first reception signal state estimation information;
Using the first reception signal state estimation information, the own vehicle identification information, the own vehicle transmission information identification information, the own vehicle transmission number information, the own vehicle transmission number information, and the fourth transmission information Own vehicle packet generating means for generating own vehicle packet;
Packet transmission means for transmitting the vehicle packet;
Other vehicle packet receiving means for receiving another vehicle packet transmitted from another vehicle;
Information extraction means for extracting other vehicle identification information, other vehicle transmission information identification information, other vehicle transmission number information and other vehicle serial number information from the other vehicle packet;
Second reception signal state estimation information generating means for generating quantized second reception signal state estimation information related to reception signal information estimation information based on the other vehicle packet;
First received information generating means for generating quantized first received information related to a received signal based on the other vehicle packet;
Processing means for obtaining a first received signal state representing the amplitude of the received signal when receiving the second received signal state estimating information based on the second received signal state estimating information;
Received signal state estimating means for estimating a second received signal state when receiving the first received information based on the first received signal state;
Second received information generating means for generating second received information based on the second received signal state and the first received information;
Puncture decoding means for performing puncture decoding on a puncture code for the second received information and generating third received information after puncture decoding;
Error correction decoding means for performing error correction decoding related to an error correction code on the third reception information and generating fourth reception information after error correction decoding;
Error detection decoding means for performing error detection decoding on an error detection code for the fourth reception information and generating fifth reception information after error detection decoding;
Other vehicle identification information that is the same as the other vehicle identification information and the other vehicle transmission information identification information related to the other vehicle packet in which the error is detected when an error is detected as a result of error detection decoding for the fourth reception information. Corresponding to the other vehicle transmission information identification information, and the reception information related to the other vehicle packet already received and the reception information related to the other vehicle packet in which the error is detected are set to the second reception signal state. And reception information combining means for generating the sixth reception information after the combination,
The puncture decoding means performs puncture decoding related to a puncture code on the sixth reception information, generates seventh reception information after puncture decoding,
The error correction decoding means performs error correction decoding related to an error correction code on the seventh reception information, generates eighth reception information after error correction decoding,
The error detection decoding means performs error detection decoding related to an error detection code on the eighth reception information, and generates ninth reception information after error detection decoding. system. The processing means obtains the amplitude and phase of the received signal as the first received signal state,
The inter-vehicle communication system according to claim 12, wherein the reception signal state estimation means estimates an amplitude and a phase of the reception signal as the second reception signal state. The processing means obtains a third received signal state of amplitude and phase with respect to the first received information,
The second reception information generating means generates the sixth reception information based on the third reception signal state and the first reception information as an alternative to the second reception signal state. The inter-vehicle communication system according to claim 13, A host vehicle puncture code determining means for determining a host vehicle puncture code for each host vehicle packet;
The puncture encoding means performs puncture encoding related to the host vehicle puncture code for the third transmission information, and generates the fourth transmission information.
The host vehicle packet generation means adds host vehicle puncture code information related to the host vehicle puncture code to the host vehicle packet,
The information extraction means extracts first other vehicle puncture code information related to a first other vehicle puncture code from the other vehicle packet,
The puncture decoding means performs puncture decoding related to the first other vehicle puncture code on the second received information to generate the third received information,
The received information synthesizing means, when an error is detected as a result of error detection decoding for the fourth received information, includes the same other vehicle identification information and other vehicle transmission information identification information as the received other vehicle packet. Combining the first other vehicle puncture code included in the corresponding plurality of other vehicle packets, generating a second other vehicle puncture code after the combination,
Further, the puncture decoding means performs puncture decoding related to the second other vehicle puncture code on the sixth reception information, and generates seventh reception information after the puncture decoding. The inter-vehicle communication system according to any one of claims 12 to 14. A vehicle error correction code determining means for determining a vehicle error correction code for each of the first transmission information;
The error correction coding means performs error correction coding on the own vehicle error correction code for the second transmission information, and generates the third transmission information,
The host vehicle packet generation means adds host vehicle error correction code information regarding the host vehicle error correction code to the host vehicle packet,
The information extraction means extracts other vehicle error correction code information related to the other vehicle error correction code from the other vehicle packet,
The error correction decoding means performs error correction decoding related to the other vehicle error correction code on the third reception information, generates the fourth reception information, and adds the seventh reception information to the seventh reception information. The vehicle-to-vehicle communication system according to any one of claims 12 to 15, wherein the eighth reception information is generated by performing error correction decoding on the other vehicle error correction code.   The vehicle-to-vehicle communication system according to any one of claims 12 to 16, further comprising own vehicle continuous transmission number information changing means for changing the own vehicle continuous transmission number information for each of the first transmission information. Channel status estimation information generating means for generating first channel status estimation information;
Channel status estimation information adding means for adding the first channel status estimation information to the vehicle packet;
Channel condition estimation information extracting means for extracting second channel condition estimation information from the other vehicle packet;
Channel information estimation means for estimating channel information at the time of receiving the other vehicle packet based on the second channel state estimation information;
Communication vehicle number information estimation means for estimating communication vehicle number information from the type of the other vehicle identification information received within a fixed time;
Communication traffic information estimation means for estimating communication traffic information from the size of the other vehicle packet received within a certain time;
Own vehicle position detecting means for detecting the own vehicle position;
Own vehicle position information adding means for adding own vehicle position information related to the own vehicle position to the own vehicle packet;
Other vehicle position information extracting means for extracting other vehicle position information from the other vehicle packet;
Map database storage means for storing the map database;
Vehicle arrangement information estimating means for estimating vehicle arrangement information representing the arrangement of the own vehicle and the other vehicle on the map based on the own vehicle position information, the other vehicle position information, and the map database;
Propagation environment information estimation means for estimating propagation environment information around the own vehicle based on the own vehicle position information and the map database;
QoS information determining means for determining QoS information;
Based on all or part of the communication vehicle number information, the channel status information, the communication traffic information, the vehicle arrangement information, the propagation environment information, and the QoS information, the own vehicle link for each of the first transmission information. The inter-vehicle communication system according to any one of claims 12 to 17, further comprising: communication control parameter determining means for determining the number-of-transmissions information, the own vehicle puncture code, and the own vehicle error correction code.

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