JP2006049972A - Wireless communication apparatus, wireless communication method, and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus, a wireless communication method, and a wireless communication system capable of detecting data collision on a transmission path. <P>SOLUTION: The wireless communication apparatus includes: a reception means for receiving packet data including received time calculation information for calculating a time required for reception from the transmission path; a reception start detection means for detecting that the reception of the packet data is started; a reception end detection means for detecting that the reception of the packet data is finished; a reception time measurement means for measuring the time required for receiving the packet data; and a collision determination means that uses the reception time calculation information included in the packet data and the measured time to determine whether or not data collision takes place in the packet data on the transmission path. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication device, a wireless communication method, and a wireless communication system.

Conventionally, a wireless communication system in which a plurality of wireless communication apparatuses perform wireless communication using the same frequency channel is known. In this type of conventional wireless communication system, after transmitting a packet, for example, a method of detecting a packet collision by detecting a carrier within a predetermined period (Patent Documents 1 and 2), A technique (Patent Document 3) is known in which a packet length is added to a packet trailer and a collision is detected on the receiving side using this length.
JP-A-8-116323 Japanese Patent Laid-Open No. 2002-247051 JP-A-11-289338

  An object of the present invention is to provide a wireless communication apparatus, a wireless communication method, and a wireless communication network that can detect a data collision on a transmission path by a method different from the conventional one.

  The wireless communication apparatus of the present invention includes a receiving unit that receives packet data storing reception time calculation information for calculating a time required for reception from a transmission path, and a reception that detects that reception of the packet data is started. Start detection means, reception end detection means for detecting completion of reception of the packet data, reception time measurement means for measuring time required for reception of the packet data, and calculation of reception time included in the packet data Collision determination means for determining whether or not a data collision has occurred in the packet data on the transmission path using the information and the measured time.

  The wireless communication method of the present invention includes a reception start detection step for detecting that reception of packet data storing reception time calculation information for calculating a time required for reception is started, and reception of the packet data is completed. A reception end detecting step for detecting the reception time, a reception time measuring step for measuring a time required to receive the packet data, a reception time calculation information included in the packet data, and the measured time. A collision detection step of determining whether or not a data collision has occurred on the data transmission path.

  The wireless communication system of the present invention includes a plurality of wireless communication devices, and the plurality of wireless communication devices perform communication using the same frequency band, and each of the wireless communication devices receives a reception signal. Receiving means for receiving packet data storing reception time calculation information for calculating the time required for receiving from the transmission path, reception start detecting means for detecting that reception of the packet data is started, and A reception end detecting means for detecting the end of reception; a reception time measuring means for measuring a time required for receiving the packet data; a reception time calculation information included in the packet data; and the measured time. And a collision determination means for determining whether or not a data collision has occurred in the packet data on the transmission line. In the wireless communication apparatus, when the occurrence of data collision is detected by the collision determination means, the frequency band to be used is switched.

  According to the present invention, a data collision on a transmission path can be detected.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a conceptual diagram of a wireless communication system 3 that performs wireless communication between a wireless base station 1 and a wireless terminal station 2 according to an embodiment of the present invention. As shown in FIG. 1, the radio base station 1 performs radio communication with one or more radio terminal stations 2 using the same frequency channel. Further, direct wireless communication may be performed between the wireless terminal stations 2 without using the wireless base station 1. In FIG. 1, three wireless terminal stations 2 are illustrated, but the number of wireless terminal stations 2 is not particularly limited. Furthermore, the radio communication system 3 may be configured only by the radio terminal station 2 that does not distinguish between radio base stations and radio terminal stations.

  FIG. 2 is a diagram showing an example of a packet format used in this embodiment. 2 includes a header 12 and a payload 13. The header 12 includes a field 14 indicating the packet reception time. In the field 14 indicating the packet reception time, the time required to receive the packet is written, and by reading the field, the time required to receive the packet can be known.

  FIG. 3 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. The wireless terminal station 2 in FIG. 3 includes an antenna 21, a header decoding unit 22, a reception time measurement unit 23, and a reception time comparison unit 24.

  FIG. 4 is a block diagram showing an example of the internal configuration of the reception time measuring unit 23 of the wireless terminal station 2 of FIG. 4 includes an input terminal 31, a power measurement unit 32, a reception level comparison unit 33, a power value differential calculation unit 34, a differential value comparison unit 35, a determination unit 36, a reception time calculation unit 37, and an output terminal. 38.

  FIG. 5 is a flowchart showing an example of a process in which the reception time measurement unit 23 of FIG. 4 measures the packet reception time. The power measuring unit 32 measures the received power (step 41) and outputs it to the reception level comparing unit 33. The power value differential calculation unit 34 calculates a differential value of the measured received power (step 42) and outputs it to the differential value comparison unit 35. The reception level comparison unit 33 compares the received power input from the power measurement unit 32 with a predetermined threshold value (step 43), and outputs the comparison result to the determination unit 36. The differential value comparison unit 35 compares the differentiation result of the power value input from the power value differentiation calculation unit 34 with a predetermined threshold value (step 44), and outputs the comparison result to the determination unit 36. The determination unit 36 determines when the reception of the packet is started based on the result input from the reception level comparison unit 33 and the result input from the differential value comparison unit 35. When a result that the received power exceeds the threshold value is input from the reception level comparing unit 33 and a result that the differential value of the power exceeds the threshold value is input from the differential value comparing unit 35, the reception of the packet is performed. It is determined that the packet has been started (step 45), and a packet reception start signal is output to the reception time calculation unit 37. Even after the reception of the packet is started, the power measuring unit 32 measures the received power (step 46) and outputs it to the reception level comparing unit 33. The power value differential calculation unit 34 calculates a differential value of the measured received power (step 47) and outputs it to the differential value comparison unit 35. The differential value comparison unit 35 compares the differentiation result of the power value input from the power value differentiation calculation unit 34 with a predetermined threshold value (step 48), and outputs the comparison result to the determination unit 36. The reception level comparison unit 33 compares the received power input from the power measurement unit 32 with a predetermined threshold value (step 49), and outputs the comparison result to the determination unit 36. Based on the result input from the reception level comparison unit 33 and the result input from the differential value comparison unit 35, the determination unit 36 determines when the reception of the packet has ended. When the reception level comparison unit 33 inputs a result that the received power falls below the threshold value and the differential value comparison unit 35 receives a result that the differential value of the power falls below the threshold value, the reception of the packet is received. It is determined that the packet has ended (step 50), and a packet reception end signal is output to the reception time calculator 37. The reception time calculation unit 37 calculates the time required for packet reception from the input time of the packet reception start signal and the input time of the packet reception end signal from the determination unit 36 (step 51). Thereafter, the processing from the initial state in FIG. 5 is repeated.

  FIG. 6 is a diagram for explaining the processing shown in FIG. 5 in which the reception time measurement unit 23 of FIG. 4 measures the reception time of a packet. 61 is a received power measured by the power measuring unit 32, 62 is a differential value of power calculated by the power value differential calculating unit 34, 63 is a threshold value 2 for determining a differential value of power, and 64 is a differential value of power. Threshold values 3 and 65 for determining the received power are threshold values 1 and 66 for determining the received power. The time t0 shown in FIG. 6 is the time when the reception level comparison unit 33 determines that the reception power exceeds the threshold value 1 in FIG. 5, and the time t1 is the time when the differential value comparison unit 35 determines the differential value of the power. This is the time when it was determined that the value 2 was exceeded. The determination unit 36 determines that reception of a packet is started at time t1 when the received power exceeds the threshold value 1 and the differential value of the power exceeds the threshold value 2. Also, time t2 shown in FIG. 6 is the time when the differential value comparison unit 35 determines that the differential value of power is below the threshold value 3, and at time t3, the reception level comparison unit 33 indicates that the received power is threshold value 1. It is the time when it was determined that the time was below. The determination unit 36 determines that the reception of the packet is completed at time t3 when the received power is lower than the threshold value 1 and the differential value of the power is lower than the threshold value 3. The reception time calculation unit 37 calculates the difference time between the time t3 and the time t1, and sets it as the packet reception time.

  FIG. 7 is a flowchart showing an example of processing in which the wireless terminal station 2 in FIG. 3 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22 and the reception time measurement unit 23. When the reception time measurement unit 23 determines the reception start of the packet input from the antenna 21 (step 71), it outputs a packet reception start signal to the header decoding unit 22. When receiving a packet reception start signal from the reception time measurement unit 23, the header decoding unit 22 starts decoding the header (step 72). When the header decoding unit 22 finishes decoding the header, it outputs the packet reception time obtained by decoding to the reception time comparison unit 24. When the reception time measuring unit 23 determines the end of packet reception, it outputs the measured packet reception time to the reception time comparing unit 24 (step 73). The reception time comparison unit 24 compares the packet reception time obtained by decoding input from the header decoding unit 22 with the packet reception time obtained by measurement input from the reception time measurement unit 23 (steps 74 and 75). If the measured reception time is longer than the reception time described in the header, it is determined that there is interference (step 77), and otherwise, it is determined that there is no interference (step 76). As will be described later, a margin may be taken into consideration when comparing the reception times.

  FIG. 8 is a diagram for explaining the processing shown in FIG. 7 in which the wireless terminal station 2 in FIG. 3 detects interference when receiving a packet. FIG. 8 shows the received packet 81, the interference 82, the packet reception time d0 obtained by decoding the header by the header decoding unit 22, and the packet reception time d1 obtained by measurement by the reception time measurement unit 23. . In FIG. 8, since the reception time comparison unit 24 has a packet reception time d1 obtained by measurement by the reception time measurement unit 23 that is longer than the packet reception time d0 obtained by decoding the header by the header decoding unit 22, It is determined that there is interference.

  FIG. 9 shows an example in which the interference wave is transmitted from the wireless communication network based on the same wireless communication standard in FIG. 8 and the interference wave is received at a time earlier than the desired packet. Show. FIG. 9 shows the interference wave 91, the desired packet 92, the packet reception time d2 obtained by decoding the header by the header decoding unit 22, and the packet reception time d3 obtained by measurement by the reception time measurement unit 23. Yes. Since the interference wave 91 shown in FIG. 9 is an interference wave from a wireless communication network based on the same standard as this wireless communication network, the packet format is the same as that of the desired packet 92. In such a case, even if the interference wave 91 is received earlier than the desired packet 92, if the field indicating the packet reception time in the header of the interference wave 91 can be correctly decoded, the same process as shown in FIG. Interference can be detected by the above process. In FIG. 9, the reception time comparison unit 24 has a packet reception time d3 obtained by the measurement by the reception time measurement unit 23 that is longer than the packet reception time d2 obtained by the header decoding unit 22 decoding the header. It is determined that there is interference.

  Thus, the interference wave can be detected by comparing the packet reception time described in the packet header with the measured packet reception time.

(Second Embodiment)
In the second embodiment, an interference wave is detected when the size of the packet is described in the packet header.

  FIG. 10 is a diagram showing an example of a packet format used in the present embodiment. The packet 11 in FIG. 10 includes a header 12 and a payload 13, and the header 12 includes a field 101 indicating the packet size. In the field 101 indicating the packet size, the size of the packet is written. The packet size is, for example, the number of bits or the number of bytes of the packet 11 or the payload 13.

  FIG. 11 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. The radio terminal station 2 in FIG. 11 includes an antenna 21, a header decoding unit 22, a reception time calculation unit 113, a reception time measurement unit 23, and a reception time comparison unit 115.

  FIG. 12 is a flowchart showing an example of processing in which the wireless terminal station 2 of FIG. 11 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22 and the reception time measurement unit 23. When the reception time measuring unit 23 determines the reception start of the packet input from the antenna 21 (step 121), it outputs a packet reception start signal to the header decoding unit 22. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 starts decoding the header (step 122). When the header decoding unit 22 finishes decoding the header, the header decoding unit 22 outputs the packet size obtained by decoding to the reception time calculation unit 113. The reception time calculation unit 113 calculates the time required to receive the packet from the packet size and transmission method input from the header decoding unit 22 (step 123). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measurement unit 23 determines the end of packet reception, the reception time measurement unit 23 outputs the measured packet reception time to the reception time comparison unit 115 (step 124). The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23 (step 125, 126) If the measured reception time is longer than the reception time described in the header, it is determined that there is interference (step 128). Otherwise, it is determined that there is no interference (step 127).

  In the above description, the example in which the size of the entire packet is described in the header 12 has been described, but interference can be detected in the same manner even when the size described in the header 12 is the size of the payload 13.

  Thus, even when the size of the packet is described in the header of the packet, the interference wave is detected by comparing the reception time obtained by calculation from the packet size with the reception time of the measured packet. be able to.

(Third embodiment)
In the third embodiment, an interference wave is detected when the size and transmission rate of the packet are described in the header of the packet.

  FIG. 13 is a diagram showing an example of a packet format used in this embodiment. 13 includes a header 12 and a payload 13. The header 12 includes a field 131 indicating a packet size and a field 132 indicating a transmission rate. In the field 131 indicating the packet size, the size of the packet is written. The packet size is, for example, the number of bits or the number of bytes of the packet 11 or the payload 13. An identifier indicating the transmission rate at which the packet is transmitted is written in the field 132 indicating the transmission rate. For example, it is “0000” for 6 Mbps and “0001” for 12 Mbps.

  The wireless terminal station 2 in this embodiment uses the same configuration as the internal configuration shown in FIG.

  FIG. 14 is a flowchart showing an example of processing in which the wireless terminal station 2 of FIG. 11 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22 and the reception time measurement unit 23. When the reception time measurement unit 23 determines the reception start of the packet input from the antenna 21 (step 151), it outputs a packet reception start signal to the header decoding unit 22. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 starts decoding the header (step 152). When header decoding is completed, the header decoding unit 22 outputs the packet size and transmission rate obtained by decoding to the reception time calculation unit 113. The reception time calculation unit 113 calculates the time required to receive the packet from the packet size and transmission rate input from the header decoding unit 22 (step 153). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measurement unit 23 determines the end of packet reception, the reception time measurement unit 23 outputs the measured packet reception time to the reception time comparison unit 115 (step 154). The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23 (step 155). 156), if the measured reception time is longer than the reception time described in the header, it is determined that there is interference (step 158). Otherwise, it is determined that there is no interference (step 157).

  In the above description, the example in which the size and the transmission rate of the entire packet are described in the header 12 has been described. However, the size and the transmission rate described in the header 12 are the same even when the size and the transmission rate of the payload 13 are used. Interference can be detected.

  The transmission rate included in the header 12 may be an identifier indicating the transmission rate, an identifier indicating the modulation method, or an identifier indicating the coding rate (for example, the coding rate of the convolutional code). Also good.

  Thus, even when the packet size and transmission rate are described in the packet header, the reception time obtained by calculation from the packet size and transmission rate is compared with the measured packet reception time. Thus, an interference wave can be detected.

(Fourth embodiment)
In the fourth embodiment, an interference wave is detected when a packet in which an error detection sequence is further added to the packet used in the third embodiment is used.

  FIG. 15 is a diagram showing an example of a packet format used in this embodiment. 15 includes a header 12, a payload 13, and an error detection sequence 15. The header 12 includes a field 131 indicating the packet size and a field 132 indicating the transmission rate. The error detection sequence 15 is an error detection code such as a CRC code, for example, and may be an error detection sequence for the payload 13 or an error detection sequence for the header 12 and the payload 13. In addition, the size of the packet is written in the field 131 indicating the packet size, and the identifier indicating the transmission rate at which the packet is transmitted is written in the field 132 indicating the transmission rate.

  FIG. 16 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. 3 includes an antenna 21, a header decoding unit 22, a reception time calculation unit 113, a reception time measurement unit 23, a reception time comparison unit 115, a packet decoding unit 161, and an error detection unit 162. And an interference detection determination unit 163.

  FIG. 17 is a flowchart illustrating an example of processing in which the wireless terminal station 2 of FIG. 16 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22, the reception time measuring unit 23, and the packet decoding unit 161. When the reception time measuring unit 23 determines the reception start of the packet input from the antenna 21 (step 171), it outputs a packet reception start signal to the header decoding unit 22. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 outputs the packet reception start signal to the packet decoding unit 161 and starts decoding the header (step 172). When header decoding is completed, the header decoding unit 22 outputs the packet size and transmission rate obtained by decoding to the reception time calculation unit 113 and the packet decoding unit 161. The reception time calculation unit 113 calculates the time required for reception of the packet from the packet size and transmission rate input from the header decoding unit 22 (step 173). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measurement unit 23 determines the end of packet reception, the reception time measurement unit 23 outputs the measured packet reception time to the reception time comparison unit 115. The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23 (step 174). 175), and outputs the comparison result to the interference detection determination unit 163. When the packet size and the transmission rate are input from the header decoding unit 22, the packet decoding unit 161 has a modulation scheme and a coding rate corresponding to the input transmission rate at a timing based on the input of the packet reception start signal. Based on the above, the data for the inputted packet size is decoded (step 176). When the packet decoding unit 161 finishes decoding the data, the packet decoding unit 161 outputs the decoded data to the error detection unit 162 (step 177). The error detection unit 162 performs an error detection process on the data input from the packet decoding unit 161 (step 178), and determines whether there is an error in the decoded data. When the determination ends, the error detection unit 162 outputs the determination result to the interference detection determination unit 163. The interference detection determination unit 163 indicates that the determination result input from the error detection unit 162 indicates a packet error, and the reception time when the comparison result input from the reception time comparison unit 115 is measured is described in the header. If the result is longer than the reception time (Yes in Step 179), it is determined that there is interference (Step 180). If not (No in Step 179), it is determined that there is no interference (Step 181).

  As described above, when an error detection sequence of the packet is added to the packet, the packet reception error detection based on the error detection sequence and the comparison of the packet reception time are combined, so that the packet data is detected by the interference wave. It can be detected that an error has occurred.

(Fifth embodiment)
In the fifth embodiment, an interference wave is detected when a packet in which an error detection sequence is further added to the packet header of the packet used in the fourth embodiment is used.

  FIG. 18 is a diagram showing an example of a packet format used in this embodiment. 18 includes a header 12, a payload 13, and a payload error detection sequence 192. The header 12 includes a field 131 indicating a packet size, a field 132 indicating a transmission rate, and a header error detection sequence 191. ing. The error detection sequence for header 191 and the error detection sequence for payload 192 may be error detection codes such as CRC codes, or may be error detection codes such as parity check bits.

FIG. 19 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. 19 includes an antenna 21, a header decoding unit 22, a header error detection unit 201, a reception time calculation unit 113, a reception time measurement unit 23, a reception time comparison unit 115, and a payload decoding unit. 202, a payload error detection unit 203, and an interference detection determination unit 163.

  FIG. 20 is a flowchart showing an example of processing in which the wireless terminal station 2 of FIG. 19 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22, the reception time measurement unit 23, and the payload decoding unit 202. When the reception time measurement unit 23 determines the reception start of the packet input from the antenna 21 (step 211), it outputs a packet reception start signal (reception timing information) to the header decoding unit 22. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 outputs the packet reception start signal to the payload decoding unit 202 and starts decoding the header (step 212). When the header decoding unit 22 finishes decoding the header, the header decoding unit 22 outputs the decoded header to the header error detection unit 201. The header error detection unit 201 performs error detection processing on the decoded header input from the header decoding unit 22 (step 213), and when it is determined that there is no error, the packet size and transmission rate information described in the header Are output to the payload decoding unit 202 and the reception time calculation unit 113 (step 214). If an error is detected in the decoded header, the reception process is terminated (step 215). The payload decoding unit 202 decodes the payload from the packet size and transmission rate information input from the header error detection unit 201 and the reception timing information input from the header decoding unit 22 (step 216). When completed, the decrypted payload is output to the payload error detection unit 203. The payload error detection unit 203 performs error detection processing on the payload input from the payload decoding unit 202 (step 217), and outputs an error detection result to the interference detection determination unit 163. The reception time calculation unit 113 calculates the time required for reception of the packet from the packet size input from the header error detection unit 201 and the transmission rate information (step 218). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measuring unit 23 determines the end of packet reception, it outputs the measured packet reception time to the reception time comparing unit 115 (step 219). The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23 (step 220). ), And outputs the comparison result to the interference detection determination unit 163. The interference detection determination unit 163 is a result in which the determination result input from the payload error detection unit 203 indicates a packet error (step 221), and the reception time in which the comparison result input from the reception time comparison unit 115 is measured. Is longer than the reception time described in the header (step 222), it is determined that there is interference (step 223). Otherwise, it is determined that there is no interference (step 224).

  In this way, when an error detection sequence for the header is added to the header of the packet, error detection processing of the packet header is performed, and after determining that there is no error in the header, the reliability without error is determined. Since packet reception time can be calculated using high header information, the accuracy of interference detection can be improved.

(Sixth embodiment)
In the sixth embodiment, a threshold is used when comparing the packet reception time calculated from the packet header information with the measured packet reception time.

  The packet format in this embodiment uses the same configuration as the packet format shown in FIG. 18, and the wireless terminal station 2 uses the same configuration as the internal configuration shown in FIG.

  FIG. 21 is a flowchart showing an example of processing in which the wireless terminal station 2 of FIG. 19 detects interference when receiving a packet. A packet input from the antenna 21 is input to the header decoding unit 22, the reception time measurement unit 23, and the payload decoding unit 202. When the reception time measurement unit 23 determines the reception start of the packet input from the antenna 21 (step 231), it outputs a packet reception start signal to the header decoding unit 22. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 outputs the packet reception start signal to the payload decoding unit 202 and starts decoding the header (step 232). When the header decoding unit 22 finishes decoding the header, the header decoding unit 22 outputs the decoded header to the header error detection unit 201. The header error detection unit 201 performs error detection processing on the decoded header input from the header decoding unit 22 (step 233), and when it is determined that there is no error, the packet size and transmission rate information described in the header Are output to the payload decoding unit 202 and the reception time calculation unit 113 (step 234). If an error is detected in the decoded header, the reception process is terminated (step 235). The payload decoding unit 202 decodes the payload from the packet size and transmission rate information input from the header error detection unit 201 and the reception timing information input from the header decoding unit 22 (step 236). When completed, the decrypted payload is output to the payload error detection unit 203. The payload error detection unit 203 performs error detection processing on the payload input from the payload decoding unit 202 (step 237), and outputs an error detection result to the interference detection determination unit 163. The reception time calculation unit 113 calculates the time required to receive the packet from the packet size input from the header error detection unit 201 and the transmission rate information (step 238). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measuring unit 23 determines the end of packet reception, it outputs the measured packet reception time to the reception time comparing unit 115 (step 239). The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23, and performs the measurement. If the packet reception time obtained is longer than the packet reception time obtained by calculation, it is determined whether or not the difference between the reception times is longer than a predetermined threshold value, and the detection result is detected as interference. It outputs to the determination part 163 (step 240). The interference detection determination unit 163 is a result in which the determination result input from the payload error detection unit 183 indicates a packet error (step 241), and the reception time at which the determination result input from the reception time comparison unit 115 is measured. Is longer than the reception time described in the header (step 242), and the difference is larger than the threshold value (step 243), it is determined that there is interference (step 244). It is determined that there is no interference (step 245).

  In this way, by using a threshold when comparing the packet reception time obtained by calculation from the header information with the packet reception time obtained by measurement, the packet reception time measurement error (for example, filtering at the time of packet reception) Measurement error caused by a gradual increase in received power due to, for example, interference detection (see FIG. 6) can be performed.

(Seventh embodiment)
In the seventh embodiment, the power of a packet being received is measured after the start of packet reception, and packet collision is detected based on a differential value of the measured power.

FIG. 22 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. The wireless terminal station 2 in FIG. 22 includes an antenna 21, a reception time measurement unit 23, and an interference detection unit 251.

FIG. 23 is a block diagram showing an example of the internal configuration of the reception time measurement unit 23, in which an output terminal 261 and an output terminal 262 are added to the block diagram of the reception time measurement unit 23 shown in FIG.

FIG. 24 is a flowchart illustrating an example of a process in which the wireless terminal station 2 in FIG. 22 detects interference after starting packet reception. When determining the packet reception start, the determination unit 36 in FIG. 23 outputs a packet reception start signal from the output terminal 262 to the interference detection unit 251 in FIG. Even after the start of packet reception, the power measurement unit 32 measures the power of the packet being received (step 46), and outputs the measurement result to the power value differentiation calculation unit 34. The power value differential calculation unit 34 calculates the differential value of the power input from the power measurement unit 32 (step 47) and outputs it to the differential value comparison unit 35. The differential value comparison unit 35 compares the power value differentiation result input from the power value differentiation calculation unit 34 with a predetermined threshold value, and compares the comparison result with the determination unit 36 and the output terminal 261. 22 to the interference detection unit 251. Based on the result input from the reception level comparison unit 33 and the result input from the differential value comparison unit 35, the determination unit 36 determines whether reception of the packet has ended (step 271). If the determination unit 36 determines that the reception of the packet has ended, it outputs a packet reception end signal to the reception time calculation unit 37 and the interference detection unit 251 of FIG. 22 via the output terminal 262 (step 50). If it is determined that packet reception is ongoing, a packet reception signal is output from the output terminal 262 to the interference detection unit 251 in FIG. The interference detection unit 251 in FIG. 22 refers to the comparison result input from the differential value comparison unit 35 via the output terminal 261 when the packet receiving signal is input from the determination unit 36, and the differential value of power is the threshold value. It is determined whether or not the value has been exceeded (step 272). If the differential value of the power exceeds the threshold value, it is determined that there is interference (step 273). If the differential value of the electric power does not exceed the threshold value, the processing after step 46 is repeated.

  FIG. 25 is a diagram for explaining the processing shown in FIG. 24 in which the wireless terminal station 2 in FIG. 22 detects an interference wave. 281 is a received power measured by the power measuring unit 32, 282 is a differential value of the power calculated by the power value differential calculating unit 34, 63 is a threshold value 2 for determining a differential value of the power, and 64 is a differential value of the power. Threshold values 3 and 283 for determining the power are threshold values 4 and 65 for determining the differential value of power, and threshold values 1 and 66 for determining the received power are noise levels. Time t0 is the time when the reception level comparing unit 33 determines that the received power exceeds the threshold value 1, and time t1 is the time when the differential value comparing unit 35 determines that the differential value of the power exceeds the threshold value 2. is there. The determination unit 36 determines that reception of a packet is started at time t1 when the received power exceeds the threshold value and the differential value of the power exceeds the threshold value. Time t2 is the time when the differential value comparison unit 35 determines that the differential value of power is below the threshold value 3, and at time t3, the reception level comparison unit 33 determines that the reception power is below the threshold value 1. It is the time. The determination unit 36 determines that the reception of the packet has been completed at time t3 when the received power is below the threshold value and the differential value of the power is below the threshold value. Time t4 is the time when the differential value comparison unit 35 determines that the differential value of power exceeds the threshold value 4. When the differential value of the power exceeds the threshold value 4 at time t4 after time t1 when the determination unit 36 determines the start of packet reception and before time t3 when the determination unit 36 determines the end of packet reception. Since the determination is made, the interference detection unit 251 determines that there is interference.

  FIG. 26 is a diagram for explaining an example of the state shown in FIG. FIG. 26 shows a received packet 291, an interference wave 292, a packet reception start time t1, a packet reception end time t3, and an interference wave detection time t4. The state shown in FIG. 25 occurs when an interference wave having a shorter reception time than the packet is generated after the packet is received.

Thus, by measuring the power during packet reception and determining a rapid increase in power from the differential value, it is possible to detect an interference wave that has collided with the packet.

(Eighth embodiment)
In the eighth embodiment, the power of a packet being received is measured after the start of packet reception, the measured power is averaged, and a packet collision is detected using a differential value of the averaged power It is.

FIG. 27 is a block diagram obtained by modifying the internal configuration of the reception time measurement unit 23 of the wireless terminal station 2 shown in FIG. The reception time measurement unit 23 of FIG. 27 is obtained by adding a power averaging processing unit 301 to the reception time measurement unit 23 shown in FIG.

FIG. 28 is a flowchart illustrating an example of a process in which the wireless terminal station 2 having the reception time measurement unit 23 illustrated in FIG. 27 detects interference after the start of packet reception. When determining the packet reception start, the determination unit 36 in FIG. 27 outputs a packet reception start signal from the output terminal 262 to the interference detection unit 251 in FIG. Even after the start of packet reception, the power measurement unit 32 measures the power of the packet being received (step 46), and outputs the measurement result to the power averaging processing unit 301. The power averaging processing unit 301 averages the power input from the power measuring unit 32 with a predetermined time width (step 311), and outputs it to the power value differential calculation unit 34. The power value differential calculation unit 34 calculates the differential value of the power input from the power averaging processing unit 301 (step 47) and outputs it to the differential value comparison unit 35. The differential value comparison unit 35 compares the power value differentiation result input from the power value differentiation calculation unit 34 with a predetermined threshold value, and compares the comparison result with the determination unit 36 and the output terminal 261. 22 to the interference detection unit 251. Based on the result input from the reception level comparison unit 33 and the result input from the differential value comparison unit 35, the determination unit 36 determines whether reception of the packet has ended (step 271). If the determination unit 36 determines that the reception of the packet has ended, it outputs a packet reception end signal to the reception time calculation unit 37 and the interference detection unit 251 of FIG. 22 via the output terminal 262 (step 50). If it is determined that packet reception is ongoing, a packet reception signal is output from the output terminal 262 to the interference detection unit 251 in FIG. The interference detection unit 251 in FIG. 22 refers to the comparison result input from the differential value comparison unit 35 via the output terminal 261 when the packet receiving signal is input from the determination unit 36, and the differential value of power is the threshold value. It is determined whether or not the value has been exceeded (step 272), and if the power differential value exceeds the threshold value, it is determined that interference has been detected (step 273). If the differential value of the electric power does not exceed the threshold value, the processing after step 46 is repeated.

  In this way, in order to detect the interference wave that collides with the packet, by using the differential value of the value obtained by averaging the power during packet reception, it is not affected by the sudden instantaneous fluctuation of the received signal due to noise or the like. Interference waves can be detected with high accuracy.

(Ninth embodiment)
In the ninth embodiment, an interference wave is detected when an error detection sequence is added to a packet.

  FIG. 29 is a diagram showing an example of a packet format used in this embodiment. The packet 11 in FIG. 29 includes data 321 and an error detection sequence 322. The error detection sequence 322 may be an error detection code such as a CRC code, or may be an error detection code such as a parity check bit.

  FIG. 30 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. 30 includes an antenna 21, a reception time measurement unit 23, a packet decoding unit 161, an error detection unit 162, and an interference detection unit 251.

  FIG. 31 is a flowchart showing an example of a process in which the wireless terminal station 2 of FIG. 30 detects interference after starting packet reception. A packet input from the antenna 21 is input to the reception time measurement unit 23 and the packet decoding unit 161. When the reception time measuring unit 23 determines the reception start of the packet input from the antenna 21, it outputs a packet reception start signal to the interference detection unit 251. Even after the start of packet reception, the reception time measurement unit 23 measures the power of the packet being received (step 46), calculates a differential value of the measured power (step 47), determines whether the packet reception has ended, and the differential value of the power. And whether or not the threshold value exceeds the threshold value. If it is determined that the packet reception has ended, a packet reception end signal is output to the packet decoding unit 161 and the interference detection unit 251, and if the power differential value exceeds the threshold value, the power differential threshold value excess signal is output to the interference detection unit 251. Output to. When the packet reception end signal is input from the reception time measurement unit 23, the packet decoding unit 161 ends decoding of the packet at a predetermined timing, and outputs the decoded packet to the error detection unit 162. The error detection unit 162 performs error detection processing on the packet input from the packet decoding unit 161 (step 331), and outputs the detection result to the interference detection unit 251. The interference detection unit 251 determines that there is no interference regardless of the result of the error detection process unless a power differential threshold excess signal is input before the packet reception end signal is input from the reception time measurement unit 23. (Step 332). The reception time measurement unit 23 performs power measurement even after the measured differential power value exceeds the threshold value and outputs the power differential threshold value excess signal to the interference detection unit 251 (step 333). Calculation is performed (step 334), and packet reception end determination is performed (step 335). If it is not determined that the packet reception is completed, the processing from step 333 is repeated, and if it is determined that the packet reception is completed, a packet reception end signal is output to the packet decoding unit 161 and the interference detection unit 251. When the packet reception end signal is input from the reception time measurement unit 23, the packet decoding unit 161 ends decoding of the packet at a predetermined timing, and outputs the decoded packet to the error detection unit 162. The error detection unit 162 performs error detection processing on the packet input from the packet decoding unit 161 (step 336), and outputs the detection result to the interference detection unit 251. The interference detection unit 251 receives a power differential threshold excess signal before the packet reception end signal is input from the reception time measurement unit 23, and the error detection processing result of the error detection unit 162 is a packet error. If it is determined that there is interference (step 338), the power differential threshold excess signal is input before the packet reception end signal is input from the reception time measurement unit 23, but it is determined that the packet is normally received. In this case, it is determined that there is no interference (step 332).

  Thus, when the error detection sequence of the packet is added to the packet, combining the packet reception error detection by the error detection sequence with the comparison with the threshold value of the differential value of the power during the packet reception. Thus, it is possible to detect an interference wave at a level that causes an error in the received packet.

(Tenth embodiment)
In the tenth embodiment, when an error detection sequence is added to a packet, interference wave detection by comparing the calculation reception time and measurement reception time and interference by comparison with the threshold value of the power differential value during packet reception Both interference detection and wave detection are performed.

  The packet format used in this embodiment has the same configuration as the packet format shown in FIG.

  FIG. 32 is a block diagram showing an example of the internal configuration of the wireless terminal station 2, which is a modification of the block diagram shown in FIG. 32 includes an antenna 21, a header decoding unit 22, a reception time calculation unit 113, a reception time measurement unit 23, a reception time comparison unit 115, a packet decoding unit 161, and an error detection unit 162. And an interference detection final determination unit 341. The internal configuration of the reception time measurement unit 23 is, for example, the block diagram shown in FIG.

FIG. 33 is a flowchart illustrating an example of processing in which the wireless terminal station 2 in FIG. 32 detects interference after starting packet reception. A packet input from the antenna 21 is input to the header decoding unit 22, the reception time measuring unit 23, and the packet decoding unit 161. When the reception time measurement unit 23 determines the reception start of the packet input from the antenna 21 (step 3001), the reception time measurement unit 23 starts measuring the packet reception time (step 3002), and outputs a packet reception start signal to the header decoding unit 22. The reception time measurement unit 23 measures the power of the packet being received even after the packet reception start determination is made (step 3003), calculates the differential value (step 3004), and compares it with the threshold value (step 3005). ), Packet reception end determination (step 3010) and determination of whether or not the differential value of power exceeds a threshold value. If it is determined that the packet reception has ended, the packet reception end signal is output to the packet decoding unit 161 and the interference detection final determination unit 341. If the power differential value exceeds the threshold value, the power differential threshold value excess signal is detected as interference. The result is output to the final determination unit 341. When the packet reception start signal is input from the reception time measurement unit 23, the header decoding unit 22 outputs the packet reception start signal to the packet decoding unit 161, and starts decoding the header (step 3006). When header decoding is completed, the header decoding unit 22 outputs the packet size and transmission rate obtained by decoding to the reception time calculation unit 113 and the packet decoding unit 161. The reception time calculation unit 113 calculates the time required to receive the packet from the packet size and transmission rate input from the header decoding unit 22 (step 3007). When the reception time calculation unit 113 finishes calculating the time required to receive the packet, the reception time calculation unit 113 outputs the calculated packet reception time to the reception time comparison unit 115. When the reception time measurement unit 23 determines the end of packet reception, the reception time measurement unit 23 ends measurement of the packet reception time (step 3011), and outputs the measured packet reception time to the reception time comparison unit 115. The reception time comparison unit 115 compares the packet reception time obtained by the calculation input from the reception time calculation unit 113 with the packet reception time obtained by the measurement input from the reception time measurement unit 23 (step 3012). The comparison result is output to the interference detection final determination unit 341. When the packet size and the transmission rate are input from the header decoding unit 22, the packet decoding unit 161 has a modulation scheme and a coding rate corresponding to the input transmission rate at a timing based on the input of the packet reception start signal. Based on the above, the data for the input packet size is decoded (step 3008). When the packet decoding unit 161 finishes decoding the data, the packet decoding unit 161 outputs the decoded data to the error detection unit 162. The error detection unit 162 performs an error detection process on the data input from the packet decoding unit 161 (step 3009), and determines whether or not there is an error in the decoded data (step 3013). When the determination ends, the error detection unit 162 outputs the determination result to the interference detection final determination unit 341. The interference detection final determination unit 341 is a result in which the determination result input from the error detection unit 162 indicates a packet error (step 3013), and the reception time in which the comparison result input from the reception time comparison unit 115 is measured. Is longer than the reception time described in the header (step 3014), it is determined that there is interference (step 3016). If not, has the received power differential value exceeded the threshold? It is determined whether or not (step 3015). If the power differential value during packet reception exceeds the threshold value, it is determined that there is interference (step 3016), and if not, it is determined that there is no interference (step 3017).

Thus, by comparing the packet reception time calculated from the header information of the packet with the measured packet reception time and the threshold value of the power differential value during reception of the packet, a delay occurs. Interference can be detected regardless of the length of the arriving interference packet.

(Eleventh embodiment)
In the eleventh embodiment, when an interference wave is detected by the interference wave detection means in the radio terminal station, a packet including content indicating interference wave detection is transmitted to the radio base station.

  FIG. 34 is a block diagram showing an example of the internal configuration of the wireless terminal station 2. The wireless terminal station 2 in FIG. 34 includes an antenna 21, an interference wave detection unit 351, and a transmission unit 352.

  FIG. 35 is a flowchart showing an example of a process in which the wireless terminal station 2 in FIG. 34 transmits a packet including contents indicating interference wave detection after the interference wave is detected. The packet input from the antenna 21 is input to the interference wave detection unit 351, and when packet reception start is determined (step 361), a packet reception process (step 362) and an interference wave detection process (step 363) are performed. The interference wave detection unit 351 repeats the processing from step 362 onward until the end of packet reception is determined. When the end of packet reception is determined (step 364), it determines whether an interference wave has been detected (step 365). If no interference wave is detected, the process ends. If the interference wave is detected, the transmission unit 352 transmits a packet including the content indicating the interference wave detection to the radio base station (step 366), and the process ends.

  In this way, by reporting that interference has been detected to the radio base station that manages and operates the radio communication network, it is possible to lead to processing for avoiding interference such as channel switching (frequency band switching).

  A threshold value may be provided for the number of times the interference wave is detected, and a packet including content indicating interference wave detection may be transmitted to the radio base station when the number of interference wave detections exceeds the threshold value.

  FIG. 36 is a flowchart illustrating an example of processing in which the wireless terminal station 2 in FIG. 34 transmits a packet including content indicating interference wave detection after the interference wave detection count exceeds the threshold count. The packet input from the antenna 21 is input to the interference wave detection unit 351, and when packet reception start is determined (step 361), a packet reception process (step 362) and an interference wave detection process (step 363) are performed. The interference wave detection unit 351 repeats the processing from step 362 onward until the end of packet reception is determined. When the end of packet reception is determined (step 364), it determines whether an interference wave has been detected (step 365). If no interference wave is detected, the processing from step 361 is repeated, and if an interference wave is detected, it is determined whether the number of interference wave detections exceeds the threshold number (step 367). If the number of detected interference waves does not exceed the threshold number of times, the processing from step 361 is repeated, and if the number of detected interference waves exceeds the threshold number of times, the content indicating interference wave detection is included. The packet is transmitted to the radio base station (step 366), and the process ends. The packet including the content indicating the interference wave detection may include information such as the number of interference wave detections, the interference wave detection level, and the interference wave detection time.

  As described above, since there is a possibility of erroneous detection in one interference wave detection, more accurate interference wave detection can be performed by providing a threshold for the number of interference wave detections.

(Twelfth embodiment)
In the twelfth embodiment, when an interference wave is detected by the interference wave detection means in the radio base station, the frequency channel on which the radio communication network operates is switched.

  FIG. 37 is a block diagram showing an example of the internal configuration of the radio base station 1. The radio base station 1 in FIG. 37 includes an antenna 21, an interference wave detection unit 351, and a transmission unit 371.

  FIG. 38 is a flowchart showing an example of a process in which the wireless base station 1 of FIG. 37 transmits a packet including contents for switching the frequency channel on which the wireless communication network operates after detecting an interference wave. The packet input from the antenna 21 is input to the interference wave detection unit 351, and when packet reception start is determined (step 361), a packet reception process (step 362) and an interference wave detection process (step 363) are performed. The interference wave detection unit 351 repeats the processing from step 362 onward until the end of packet reception is determined. When the end of packet reception is determined (step 364), it determines whether an interference wave has been detected (step 365). If no interference wave is detected, the process ends. If an interference wave is detected, a packet including the content for switching the frequency channel on which the wireless communication network operates is transmitted to the wireless terminal station 2 (step 381), and the process ends. The packet indicating channel switching transmitted from the radio base station 1 may include information such as timing information for switching channels, a channel number of a switching destination, and the like.

  As described above, when an interference wave is detected, by switching to a frequency channel that does not have interference, smooth communication in which transmission characteristics are not deteriorated due to interference can be performed.

  A threshold is provided for the number of times the interference wave is detected, and a packet including content for switching the frequency channel on which the wireless communication network operates is transmitted to the wireless terminal station 2 when the number of detected interference waves exceeds the threshold value. You may send it.

  FIG. 39 is a flowchart showing an example of a process in which the wireless base station 1 of FIG. 37 transmits a packet including contents for switching the frequency channel on which the wireless communication network operates after the interference wave detection count exceeds the threshold count. . The packet input from the antenna 21 is input to the interference wave detection unit 351, and when packet reception start is determined (step 361), a packet reception process (step 362) and an interference wave detection process (step 363) are performed. The interference wave detection unit 351 repeats the processing from step 362 onward until the end of packet reception is determined. When the end of packet reception is determined (step 364), it determines whether an interference wave has been detected (step 365). If no interference wave is detected, the processing from step 361 is repeated, and if an interference wave is detected, it is determined whether the number of interference wave detections exceeds the threshold number (step 367). If the number of detected interference waves does not exceed the threshold number of times, the processing from step 361 is repeated, and if the number of detected interference waves exceeds the threshold number of times, the frequency channel on which the wireless communication network operates is selected. A packet including the contents to be switched is transmitted to the wireless terminal station 2 (step 381), and the process ends. The packet indicating channel switching transmitted from the radio base station 1 may include information such as timing information for switching channels, a channel number of a switching destination, and the like.

  In this way, since there is a possibility of erroneous detection in one interference wave detection, a threshold is set for the number of interference wave detections, and when the number of interference wave detections exceeds the threshold number of times, there is no interference. Switching to a channel enables smooth communication with no deterioration in transmission characteristics due to interference.

(13th Embodiment)
In the thirteenth embodiment, when the wireless base station 1 receives a packet indicating the content of the detected interference wave from the wireless terminal station 2, the frequency channel on which the wireless communication network operates is switched.

  FIG. 40 is a block diagram showing an example of the internal configuration of the radio base station 1. The radio base station 1 in FIG. 40 includes an antenna 21, a receiving unit 391, and a transmitting unit 371.

  FIG. 41 shows a process of transmitting a packet including contents for switching the frequency channel on which the radio communication network operates when the radio base station 1 of FIG. 40 receives a packet indicating the contents of detecting an interference wave from the radio terminal station 2. It is a flowchart which shows an example. The packet input from the antenna 21 is input to the receiving unit 391. When the packet reception start is determined (step 361), packet reception processing is performed (step 362). The reception unit 391 repeats the processing from step 362 onward until it determines the end of packet reception. When it determines the end of packet reception (step 364), it receives a packet including the content of detecting an interference wave from the wireless terminal station 2. It is determined whether or not (step 401). If the packet containing the content that detected the interference wave is not received, the process is terminated. If the packet containing the content that detected the interference wave is received, the packet containing the content that switches the frequency channel on which the wireless communication network operates is received. Transmit to the wireless terminal station 2 (step 381), and the process ends. The packet indicating channel switching transmitted from the radio base station 1 may include information such as timing information for switching channels, a channel number of a switching destination, and the like.

  In this way, when a packet indicating interference wave detection is received from the wireless terminal station 2, the wireless communication network as a whole performs smooth communication with no deterioration of transmission characteristics due to interference by switching to a frequency channel without interference. Can do.

  A threshold is set for the number of times the packet indicating interference wave detection from the wireless terminal station 2 is received, and the wireless communication network operates when the number of times the packet indicating interference wave detection exceeds the threshold number A packet including contents for switching frequency channels may be transmitted to the wireless terminal station 2.

  FIG. 42 includes contents for switching the frequency channel on which the wireless communication network operates after the number of times that the wireless base station 1 of FIG. 40 has received a packet indicating interference wave detection from the wireless terminal station 2 exceeds the threshold number. 6 is a flowchart illustrating an example of a process for transmitting a packet. The packet input from the antenna 21 is input to the receiving unit 391. When the packet reception start is determined (step 361), packet reception processing is performed (step 362). Whether the reception unit 391 repeats the processing from step 362 onward until it determines the end of packet reception, and determines whether the reception of the packet has been received (step 364). It is determined whether or not (step 401). If the packet including the content of detecting the interference wave is not received, the processing from step 361 is repeated, and if the packet including the content of detecting the interference wave is received, reception of the packet including the content of the interference wave detection is received. It is determined whether or not the number of times exceeds the threshold number (step 411). If the number of receptions of packets including the contents of interference wave detection does not exceed the threshold number of times, the processing after step 361 is repeated, and the number of receptions of packets including the contents of interference wave detection exceeds the threshold number of times. Then, a packet including the content for switching the frequency channel on which the wireless communication network operates is transmitted to the wireless terminal station 2 (step 381), and the process ends. The reception of a plurality of packets indicating the content of detecting the interference wave from the wireless terminal station 2 may be reception from the same wireless terminal station 2 or reception from a plurality of different wireless terminal stations 2. May be. Also, the packet indicating channel switching transmitted by the radio base station 1 may include information such as timing information for switching channels, a channel number of the switching destination, and the like.

  As described above, in one interference wave detection report from the wireless terminal station 2, there is a possibility of reporting due to erroneous detection. Therefore, a threshold is set for the number of receptions of interference wave detection reports, and the number of interference wave detection reports is the threshold. When the number of values is exceeded, by switching to a frequency channel that does not have interference, the entire wireless communication network can perform smooth communication in which transmission characteristics do not deteriorate due to interference.

(Fourteenth embodiment)
In the fourteenth embodiment, a communication method and a wireless communication network for switching a frequency channel on which a wireless communication network operates when an interference wave is detected during packet reception will be described.

  FIG. 43 is a flowchart showing an example of processing for switching the frequency channel on which the wireless communication network operates when the wireless terminal station 2 detects an interference wave in the wireless communication network 3 of FIG. When the wireless terminal station 2 in FIG. 1 determines the start of packet reception (step 421), it performs packet reception processing until the packet reception ends (steps 422 and 423). When the packet reception ends, the received packet contains an error. It is determined whether or not there is (step 424). If there is no error in the received packet, the frequency channel is not switched, and the processing ends as it is. If an error is detected in the received packet, the measured packet reception time is compared with the packet reception time obtained by calculation (step 425). If the measured packet reception time is longer than the calculated packet reception time, the frequency channel is switched (step 427). Otherwise, it is determined whether the differential value of power exceeds the threshold during packet reception (step 427). 426). If the differential value of the power exceeds the threshold during packet reception, the frequency channel is switched (step 427). Otherwise, the frequency channel is not switched and the process ends.

  In this way, when interference is detected, a network in which transmission characteristics are not deteriorated by interference can be operated by switching the entire network to a frequency channel that does not have interference.

A diagram representing a wireless communication network composed of one base station and three terminal stations A diagram showing the format of a packet consisting of a header with packet reception time and a payload The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from an antenna, a header decoding part, a reception time measurement part, and a reception time comparison part The figure which showed the internal structure of the reception time measurement part comprised from a power measurement part, a reception level comparison part, a power value differential calculation part, a differential value comparison part, a determination part, and a reception time calculation part The flowchart which shows an example of the process which the reception time measurement part 23 of FIG. 4 measures the reception time of a packet. The figure for demonstrating the process shown in FIG. 5 in which the reception time measurement part 23 of FIG. The flowchart which shows an example of the process which the radio | wireless terminal station 2 of FIG. 3 detects interference at the time of packet reception The figure for demonstrating the process shown in FIG. 7 which the radio | wireless terminal station 2 of FIG. 3 detects interference at the time of packet reception The figure for demonstrating the case where an interference wave is transmitted from the radio | wireless communication network based on the same radio | wireless communication standard in FIG. A diagram showing the format of a packet consisting of a header describing the packet size and a payload The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from a header decoding part, a reception time calculation part, a reception time measurement part, and a reception time comparison part The flowchart which shows an example of the process which the wireless terminal station 2 of FIG. 11 detects interference at the time of packet reception A diagram showing the format of a packet consisting of a header describing the packet size and transmission rate, and a payload The flowchart which shows an example of the process which the wireless terminal station 2 of FIG. 11 detects interference at the time of packet reception A diagram showing the format of a packet consisting of a header describing the packet size and transmission rate, a payload, and an error detection sequence The figure which showed the internal structure of the radio | wireless terminal station comprised from a header decoding part, a reception time calculation part, a reception time measurement part, a reception time comparison part, a packet decoding part, an error detection part, and an interference detection determination part FIG. 16 is a flowchart illustrating an example of processing in which the wireless terminal station 2 detects interference when receiving a packet. A diagram showing the format of a packet composed of a header composed of a packet size, a transmission rate, and a header error detection sequence, a payload, and a payload error detection sequence. The internal configuration of the wireless terminal station 2 including a header decoding unit, a header error detection unit, a reception time calculation unit, a reception time measurement unit, a reception time comparison unit, a payload decoding unit, a payload error detection unit, and an interference detection determination unit is shown. Figure FIG. 19 is a flowchart illustrating an example of processing in which the wireless terminal station 2 detects interference when receiving a packet. FIG. 19 is a flowchart illustrating an example of processing in which the wireless terminal station 2 detects interference when receiving a packet. The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from a reception time measurement part and an interference detection part. The figure which showed the internal structure which added the output terminals 261 and 262 to the reception time measurement part 23 of FIG. 22 is a flowchart showing an example of processing for detecting interference after the wireless terminal station 2 in FIG. 22 starts receiving packets. The figure for demonstrating the process shown in FIG. 24 in which the radio | wireless terminal station 2 of FIG. 22 detects an interference wave The figure for demonstrating the example of reception of the packet which causes the state shown in FIG. The figure which showed the internal structure which added the power average process part to the reception time measurement part 23 of FIG. The flowchart which shows an example of the process which the radio | wireless terminal station 2 shown in FIG. 22 which has the reception time measurement 23 shown in FIG. A diagram showing the format of a packet consisting of data and an error detection sequence The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from an antenna, a packet decoding part, a reception time measurement part, an error detection part, and an interference detection part 30 is a flowchart illustrating an example of processing in which the wireless terminal station 2 in FIG. 30 detects interference after starting packet reception. The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from an antenna, a packet decoding part, an error detection part, a header decoding part, a reception time calculation part, a reception time comparison part, a reception time measurement part, and an interference detection final determination part The flowchart which shows an example of the process which the radio | wireless terminal station 2 of FIG. 32 detects interference after a packet reception start The figure which showed the internal structure of the radio | wireless terminal station 2 comprised from an antenna, an interference wave detection part, and a transmission part FIG. 34 is a flowchart illustrating an example of processing in which the wireless terminal station 2 transmits a packet including content indicating interference wave detection after the interference wave is detected. 34 is a flowchart illustrating an example of processing in which the wireless terminal station 2 in FIG. 34 transmits a packet including content indicating interference wave detection after the interference wave detection count exceeds the threshold count. The figure which showed the internal structure of the radio base station comprised from an antenna, an interference wave detection part, and a transmission part FIG. 37 is a flowchart illustrating an example of a process in which the wireless base station 1 transmits a packet including contents for switching a frequency channel on which the wireless communication network operates after detecting an interference wave. FIG. 37 is a flowchart illustrating an example of a process in which the wireless base station 1 transmits a packet including contents for switching a frequency channel on which the wireless communication network operates after the number of interference wave detections exceeds the threshold number. The figure which showed the internal structure of the wireless base station 1 comprised from an antenna, a receiving part, and a transmission part 40 shows an example of a process for transmitting a packet including content for switching a frequency channel on which the wireless communication network operates when the wireless base station 1 of FIG. 40 receives a packet indicating the content of detecting an interference wave from the wireless terminal station 2. flowchart After the number of times that the radio base station 1 of FIG. 40 has received a packet indicating interference wave detection from the radio terminal station exceeds the threshold count, a packet including contents for switching the frequency channel on which the radio communication network operates is transmitted. Flowchart showing an example of processing 1 is a flowchart illustrating an example of processing for switching a frequency channel on which a wireless communication network operates when a wireless terminal station detects an interference wave in the wireless communication network of FIG.

Explanation of symbols

1: wireless base station 2: wireless terminal station 3: wireless communication system 21: antenna 22: header decoding unit 23: reception time measurement unit 24, 115: reception time comparison unit 32: power measurement unit 33: reception level comparison unit 34: Power value differential calculation unit 35: differential value comparison unit 36: determination unit 37, 113: reception time calculation unit 161: packet decoding unit 162: error detection unit 163: interference detection determination unit 201: header error detection unit 202: payload decoding unit 203: Payload error detection unit 251: Interference detection unit 301: Power averaging processing unit 341: Interference detection final determination unit 351: Interference wave detection unit 352, 371: Transmission unit 391: Reception unit

Claims (16)

Receiving means for receiving, from the transmission path, packet data storing reception time calculation information for calculating the time required for reception;
Reception start detection means for detecting that reception of the packet data is started;
A reception end detection means for detecting that the reception of the packet data has ended,
Receiving time measuring means for measuring the time required for receiving the packet data;
Collision determination means for determining whether or not a data collision has occurred in the packet data on the transmission path using the reception time calculation information included in the packet data and the measured time;
A wireless communication device comprising: The packet data includes, as the reception time calculation information, a reception reception time predicted to be required for reception of the packet data on the reception side,
The wireless communication apparatus according to claim 1, wherein the collision determination unit determines whether a data collision has occurred in the packet data based on the predicted reception time and the measured time.   The collision determination unit determines that a data collision has occurred in the packet data when a difference between the predicted reception time and the measured time satisfies a criterion based on a predetermined threshold value. The wireless communication apparatus according to claim 2. The packet data further includes error detection information,
The collision determination means determines whether or not there is an error in the packet data using the error detection information, and if there is an error and the difference satisfies a criterion based on the threshold, the packet data 4. The wireless communication apparatus according to claim 3, wherein it is determined that a data collision has occurred. The packet data includes the size of the packet data as the reception time calculation information,
The collision determination unit calculates a time required to receive the packet data by using transmission method information of the packet data stored in advance and the size of the packet data, and calculates the calculated time and the measured The wireless communication apparatus according to claim 1, wherein it is determined whether a data collision has occurred in the packet data based on time. The packet data includes, as the reception time calculation information, the size of the packet data and the transmission method information of the packet data,
The collision determination unit calculates a time required to receive the packet data using the size of the packet data and the transmission method information of the packet data, and based on the calculated time and the measured time The wireless communication apparatus according to claim 1, wherein it is determined whether a data collision has occurred in the packet data.   The collision determination means determines that a data collision has occurred in the packet data when a difference between the calculated time and the measured time satisfies a criterion based on a predetermined threshold. The wireless communication apparatus according to claim 5 or 6, characterized in that The packet data further includes error detection information,
The collision determination means determines whether or not there is an error in the packet data using the error detection information, and if there is an error and the difference satisfies a criterion based on the threshold, the packet data 8. The wireless communication apparatus according to claim 7, wherein it is determined that a data collision has occurred. Received power measuring means for sequentially measuring the received power of the packet data being received;
Differential value calculation means for calculating a differential value of the received power, and
The reception start detection means detects that reception of the packet data is started based on the received power and the differential value,
The reception end detection means detects that the reception of the packet data has ended based on the received power and the differential value.
The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. Further comprising averaging means for sequentially calculating an average value of the measured received power over a certain period of time;
The differential value calculating means calculates a differential value of the average value.
The wireless communication apparatus according to claim 9.   The collision determination means is after the reception start detection means detects that the reception of the packet data is started, and before the reception end detection means detects that the reception of the packet data is completed. The wireless communication apparatus according to claim 9, wherein when the differential value satisfies a criterion based on a predetermined threshold value, it is determined that a data collision has occurred in the packet data. The packet data further includes error detection information,
The collision determination means determines whether there is an error in the packet data using the error detection information, an error exists, and the differential value of the received power satisfies a criterion based on the threshold The wireless communication apparatus according to claim 11, wherein the wireless communication apparatus determines that a data collision has occurred in the packet data.   The transmission apparatus according to claim 1, further comprising a transmission unit configured to transmit packet data indicating that a data collision has been detected to a destination device when a collision is detected by the collision determination unit a predetermined number of times. The wireless communication apparatus according to any one of 1 to 12.   And a transmission unit configured to transmit packet data for instructing switching of a frequency band to be used to a destination device when collision detection is performed a predetermined number of times by the collision determination unit. Item 14. The wireless communication device according to any one of Items 1 to 13. A reception start detection step for detecting that reception of packet data storing reception time calculation information for calculating a time required for reception is started;
A reception end detection step for detecting the end of reception of the packet data;
A reception time measuring step for measuring a time required for receiving the packet data;
A collision detection step of determining whether or not a data collision has occurred on the transmission path of the packet data using the reception time calculation information included in the packet data and the measured time;
A wireless communication method comprising: A plurality of wireless communication devices, wherein the plurality of wireless communication devices are wireless communication systems that perform communication using the same frequency band,
Each of the wireless communication devices is
Receiving means for receiving, from the transmission path, packet data storing reception time calculation information for calculating the time required for reception;
Reception start detection means for detecting that reception of the packet data is started;
A reception end detection means for detecting that the reception of the packet data has ended,
Receiving time measuring means for measuring the time required for receiving the packet data;
Collision determination means for determining whether or not a data collision has occurred in the packet data on a transmission path using the reception time calculation information included in the packet data and the measured time,
When occurrence of data collision is detected by the collision determination means in at least one of the wireless communication devices, the frequency band to be used is switched.
A wireless communication system.

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