WO2015063993A1 - 衝突検出装置、通信装置、衝突検出方法、及びプログラム - Google Patents
衝突検出装置、通信装置、衝突検出方法、及びプログラム Download PDFInfo
- Publication number
- WO2015063993A1 WO2015063993A1 PCT/JP2014/004575 JP2014004575W WO2015063993A1 WO 2015063993 A1 WO2015063993 A1 WO 2015063993A1 JP 2014004575 W JP2014004575 W JP 2014004575W WO 2015063993 A1 WO2015063993 A1 WO 2015063993A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transmission
- packet
- power
- collision detection
- detection unit
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access, e.g. scheduled or random access
- H04W74/08—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access]
- H04W74/0833—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using a random access procedure
- H04W74/0841—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using a random access procedure with collision treatment
- H04W74/0858—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using a random access procedure with collision treatment collision detection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access, e.g. scheduled or random access
- H04W74/08—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access]
- H04W74/0808—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using carrier sensing, e.g. as in CSMA
- H04W74/0825—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using carrier sensing, e.g. as in CSMA carrier sensing with collision detection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/22—Parsing or analysis of headers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/30—Definitions, standards or architectural aspects of layered protocol stacks
- H04L69/32—Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
- H04L69/322—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions
- H04L69/324—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions in the data link layer [OSI layer 2], e.g. HDLC
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/08—Testing, supervising or monitoring using real traffic
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/28—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
- H04W52/286—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission during data packet transmission, e.g. high speed packet access [HSPA]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
- H04L1/0083—Formatting with frames or packets; Protocol or part of protocol for error control
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/265—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account the quality of service QoS
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/12—WLAN [Wireless Local Area Networks]
Definitions
- the present invention relates to a collision detection device, a communication device, a collision detection method, and a program for detecting packet collision.
- IEEE 802.11 uses a CSMA / CA (Carrier Sense Multiple Access / Collection Avoidance) scheme for the purpose of suppressing interference between WLAN devices.
- CSMA / CA Carrier Sense Multiple Access / Collection Avoidance
- the CSMA / CA method cannot completely avoid packet collision.
- the reason is that even if it is determined that the channel scheduled for communication is free by carrier sensing, packet collision occurs if the communication start timings of a plurality of users are the same.
- Another reason is that when the power of the transmission signal of another user is weaker than the detection threshold, the presence of the packet cannot be detected by carrier sensing.
- the packet is a unit of transmission / reception data handled in the data link layer in the seven layers of OSI.
- the technique described in Patent Document 1 can correctly determine whether or not a packet collision has occurred.
- the difference ⁇ H between the average value H1 of the received power in the current reception period and the average value H2 of the received power in the previous reception period is equal to or greater than a predetermined threshold Th. Since it is determined whether or not a packet collision has occurred based on whether or not the transmission power of the transmission device changes, there is a problem that a correct determination result cannot be obtained.
- Such problems include a transmitter having a power control function for switching transmission power based on the strength of a signal transmitted from a communication partner, a packet loss rate, and the like, and a function for switching transmission power according to a setting operation performed by a user. Occurs when using a transmitting device.
- An object of the present invention is to provide a collision detection apparatus that solves the problem that the presence or absence of packet collision cannot be detected correctly when the transmission power of the transmission apparatus changes.
- the collision detection apparatus is A collision detection device that detects a collision between the transmitted packet and another packet in a communication device having a transmission device that wirelessly transmits a packet, A power detector that samples the power of a spatial radio signal in a packet transmission period in which the transmitter is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and a reference value is calculated based on the transmission power of the packet.
- a collision detection unit that determines and detects the collision of the packet by comparing the index value with the reference value.
- the communication device is A transmitter for transmitting packets wirelessly;
- a power detection unit that samples the power of a spatial radio signal in a packet transmission period in which the transmission unit is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling by the power detection unit, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and based on the transmission power of the packet
- a collision detection unit that determines a reference value and compares the index value with the reference value to detect the presence or absence of the packet collision.
- a collision detection method includes: A packet collision detection method executed by a communication device that transmits a packet wirelessly, Sampling the power of the spatial radio signal in the packet transmission period that is transmitting the packet, Based on the sampling data obtained by sampling, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, A reference value is determined based on the transmission power of the packet, The index value is compared with the reference value to detect the presence of collision between the packet and another packet.
- the program according to the present invention is: Computer A transmitter for transmitting packets wirelessly; A power detection unit that samples the power of a spatial radio signal in a packet transmission period in which the transmission unit is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling by the power detection unit, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and based on the transmission power of the packet A reference value is determined, and the index value is compared with the reference value to function as a collision detection unit that detects the presence or absence of collision of the packet.
- the present invention it is possible to correctly detect the presence or absence of a packet collision even when the transmission power of the transmission apparatus changes.
- a communication device 10 according to the first embodiment of the present invention includes a transmission device 11 and a collision detection device 12.
- the transmission device 11 transmits a communication packet conforming to IEEE 802.11 (sometimes simply referred to as a packet), and includes a transmission unit 111, a clock 112, an information management unit 113, a disk device, a semiconductor memory, and the like.
- a storage device 114 and an antenna 116 are provided.
- the storage device 114 is provided with a transmission parameter storage unit 115.
- transmission parameters including the transmission power of each transmitted packet, the transmission start time, and the transmission end time are recorded.
- FIG. 2 is a diagram illustrating an example of the contents of the transmission parameter storage unit 115.
- the transmission parameter storage unit 115 of this example has a plurality of rows, and the transmission power, transmission start time, and transmission end time of the transmitted packet are recorded in each row. For example, the first row indicates that transmission of a packet is started at time t1 with transmission power W1, and transmission of the packet is completed at time t2.
- the transmission unit 111 transmits the packet based on the function of transmitting the packet using the selected communication frequency channel, the setting operation performed by the user, the strength of the signal transmitted from the communication partner, the packet loss rate, and the like. And a function of recording a transmission parameter of each transmitted packet in the transmission parameter storage unit 115.
- the clock 112 has a function of displaying time.
- the information management unit 113 transmits a time displayed on the clock 112 on the transmission device 11 side to the collision detection device 12 in response to a time acquisition request sent from the collision detection device 12, and the collision detection device 12. And a function for transmitting the transmission parameters recorded in the transmission parameter storage unit 115 to the collision detection device 12 in response to the transmission parameter acquisition request sent from the network.
- the transmission unit 111 records the transmission parameter in the transmission parameter storage unit 115, but the information management unit 113 records the transmission parameter generated by the transmission unit 111 in the transmission parameter storage unit 115. You may make it do.
- the transmission part 111 and the information management part 113 are realizable by CPU (central processing unit), In that case, it carries out as follows, for example.
- the CPU realizes the transmission unit 111 and the information management unit 113 on its own CPU by controlling its own operation according to the read program.
- the collision detection device 12 has a function of determining whether or not the packet transmitted from the transmission device 11 collides with a packet transmitted from another wireless device.
- the collision detection device 12 includes a power detection unit 121, a clock 122, a collision detection unit 123, a storage device 124, and an antenna 127.
- the storage device 124 includes a sampling data storage unit 125 and a threshold storage unit 126.
- the sampling data (power value) of the power of the spatial radio wave signal existing in the frequency band (communication frequency channel) used when the transmission unit 111 transmits the packet, and the sampling time thereof are stored. Recorded in association.
- FIG. 3 is a diagram showing an example of the contents of the sampling data storage unit 125.
- the sampling data storage unit 125 in this example has a plurality of rows, and the power value and the sampling time are recorded in each row. For example, the first row indicates that the power value SD1 is sampled at time ST1.
- the threshold value storage unit 126 stores a threshold value A used when determining whether or not a packet collision has occurred.
- the threshold storage unit 126 records threshold A candidates in association with transmission powers that can be taken when the transmission unit 111 transmits a packet.
- FIG. 4 is a diagram showing an example of the contents of the threshold storage unit 126.
- the threshold storage unit 126 in this example has a plurality of rows, and the transmission power and the threshold A are recorded in each row. For example, the first line indicates that the threshold A is set to “Tha” when the transmission power of the packet is “W1”. In general, the threshold A is larger as the transmission power is larger. A specific method for determining the threshold A will be described later.
- the power detection unit 121 senses the power of the spatial radio signal existing in the frequency band used by the transmission unit 111 for packet transmission, and associates the sampling data (power value) with the sampling time to store the sampling data.
- the clock 122 has a function of displaying time.
- the collision detection unit 123 has the following functions.
- a function of transmitting a time acquisition request to the information management unit 113 A function of transmitting a time acquisition request to the information management unit 113.
- the time indicated by the clock 122 on the collision detection device 12 side matches the time indicated by the clock 112 based on the time indicated by the clock 112 on the transmission device 11 side sent from the information management unit 113 in response to the time acquisition request. Function to let you.
- the transmission parameter sent from the information management unit 113 in response to the transmission parameter acquisition request, the sampling data and sampling time recorded in the sampling data storage unit 125, and the threshold value recorded in the threshold storage unit 126 A function for determining whether or not a packet transmitted from the transmission apparatus 11 collides with a packet transmitted from another wireless device based on the above.
- the power detection unit 121 and the collision detection unit 123 can be realized by a program-controlled CPU.
- the transmission of the packet by the transmission device 11 and the sensing of the spatial radio signal by the collision detection device 12 are performed asynchronously.
- the transmission unit 111 transmits data divided into packets the processing shown in FIG. 5 is performed.
- step S51 a process of matching the time indicated by the clock 112 on the transmission device side with the time indicated by the clock 122 on the collision detection device side is performed (step S51). Specifically, for example, the time of the clocks 112 and 122 is matched by performing the following processing. First, the collision detection unit 123 transmits a time acquisition request to the information management unit 113. Next, the information management unit 113 inputs the time from the clock 112 and transmits it to the collision detection unit 123.
- step S51 based on the time sent by the collision detection unit 123 from the information management unit 113 and the time required for the time setting processing to be completed after the information management unit 113 performs the time input processing, The time to be set is determined and the time is set in the clock 122. The above is the details of the processing performed in step S51.
- the power detection unit 121 starts a sensing process (step S52).
- the power detection unit 121 senses the power of the spatial radio signal existing in the frequency band used by the transmission unit 111 for packet transmission, and samples it at a predetermined sampling frequency. Then, the sampled power value (sampling data) and the sampling time are associated with each other and recorded in the sampling data storage unit 125.
- step S53 When the power detection unit 121 performs the sensing process for a predetermined power sensing time, the sensing process ends (step S53).
- the collision detection unit 123 transmits a transmission parameter acquisition request to the information management unit 113 (step S54).
- the information management unit 113 transmits the transmission parameters (transmission power, transmission start time, transmission end time) of each packet recorded in the transmission parameter storage unit 115. Is detected) to the collision detection unit 123 (step S55).
- the collision detection unit 123 Based on the transmission start time and transmission end time of each packet notified from the information management unit 113 and the sampling time recorded in the sampling data storage unit 125, the collision detection unit 123 Sampling data (power value) sampled in the transmission period is extracted from the sampling data storage unit 125, and an average value (average power) of the extracted sampling data is calculated (step S56).
- the thresholds Tha, Thb, Thc,... For the transmission powers W1, W2, W3,... are determined as follows, for example. First, in an environment where there is no spatial radio signal of another radio, a packet is transmitted from the transmission unit 111 with transmission power W1. Next, the average value of the received power in the packet transmission period is calculated by performing the same processing as in steps S51 to S56 described above. Thereafter, a power fluctuation component due to environmental noise and device noise is added to the calculated average value, and the addition result Tha is set as a threshold A for the transmission power W1. The same processing is performed for the other transmission powers W2, W3,... To determine threshold values Thb, Thc,.
- the collision detection unit 123 compares the average value of the power during the transmission period of each packet calculated in step S56 with the threshold A for each packet determined in step S57 (step S58).
- Step S59 If there is an average value exceeding the threshold A in the average value of the power in the transmission period of each packet calculated in step S56 (Yes in step S58), it is determined that a packet collision occurs ( Step S59). On the other hand, when all the average values are equal to or less than the threshold A (No in step S58), it is determined that no packet collision has occurred (step S60).
- the clocks 112 and 122 are provided on the transmission device 11 side and the collision detection device 12 side, respectively. Instead, only one clock shared by the transmission device 11 and the collision detection device 12 is provided. You may make it provide. In this case, the process of step S51 in FIG. However, in this case, in order to operate the transmission device 11 and the collision detection device 12 at the same time, the transmission delay time when the time information is transmitted from the clock to the transmission device 11 and the time information from the clock to the collision detection device 12 are It is necessary to arrange the circuit (install a clock or wiring) so that the transmission delay time during transmission is the same. In this case, a clock generation circuit and a counter can be used in combination instead of the clock.
- the power detection unit 121 calculates the average power during the packet transmission period based on the power of the spatial radio wave signal sensed between the transmission start time and the transmission end time managed by the information management unit 113. Because it is.
- the threshold value storage unit 126b shown in FIG. 6 is used instead of the threshold value storage unit 126 shown in FIG. 4, and the communication device 10 executes the process shown in FIG. 7 instead of the process shown in FIG. This is realized.
- the threshold value storage unit 126b includes transmission candidates that the transmission unit 111 can take when candidates for threshold values A and B used when determining whether or not a packet collision has occurred. It is recorded in association with each power.
- the threshold A is used when determining whether or not a packet collision has occurred based on the average value of the received power during the packet transmission period.
- the threshold B is used when determining whether or not a packet collision has occurred based on the degree of variation in the sampling data (power value) sampled during the packet transmission period.
- the threshold storage unit 126b illustrated in FIG. 6 has a plurality of rows, and transmission power, threshold A, and threshold B are recorded in each row. For example, the first line indicates that when the transmission power of the packet is “W1”, the thresholds A and B are set to “Tha” and “Thx”, respectively.
- the communication device 10 first performs the same processing as steps S51 to S58 of FIG.
- Step S59 If there is an average value exceeding the threshold A in the average value of the power in the transmission period of each packet calculated in step S56 (Yes in step S58), it is determined that a packet collision occurs ( Step S59). On the other hand, when all the average values are equal to or less than the threshold A (No in step S58), the process of step S61 is performed.
- step S61 the collision detection unit 123 determines a threshold B for each packet based on the transmission power of each packet notified from the information management unit 113. More specifically, a threshold B candidate recorded in association with the transmission power notified from the information management unit 113 is searched from the threshold storage unit 126, and the searched candidate is set as the threshold B.
- the collision detection unit 123 for each packet, based on the transmission start time and transmission end time of each packet notified from the information management unit 113 and the sampling time recorded in the sampling data storage unit 125, Sampling data sampled during the packet transmission period is extracted from the sampling data storage unit 125, and the degree of variation is calculated (step S62).
- the degree of variation for example, a variance calculated by the following equation (1) is used.
- the degree of variation is not limited to this, and a standard deviation or the like may be used.
- ⁇ i is the i-th sampling data among the sampling data sampled during the packet transmission period
- ⁇ is the average value of ⁇ i (the average value obtained in step S56).
- the collision detection unit 123 compares the degree of variation with the threshold B (step S63). When the degree of variation exceeds the threshold B (Yes in step S63), it is determined that a packet collision has occurred (step S59). On the other hand, when the degree of variation is equal to or less than the threshold value B (No in step S63), it is determined that no packet collision has occurred (step S60).
- the threshold value B corresponding to the transmission power of the packet is determined as follows, for example. Specifically, thresholds Thx, Thy, Thz,... For transmission powers W1, W2, W3,... are determined as follows. First, in an environment where there is no other spatial radio signal of the radio, a packet is transmitted from the transmission unit 111 with transmission power W1. Thereafter, in the same manner as described above, the degree of variation is calculated (step S62), and the calculated degree of variation or a value obtained by correcting the calculated degree of variation in consideration of environmental noise or the like is set as a threshold Thx for the transmission power W1. . The same processing is performed for the other transmission powers W2, W3,... To determine threshold values Thy, Thz,. In addition, it is possible to transmit a packet a plurality of times with the transmission power for one transmission power, calculate the degree of variation for each time, and set the maximum degree of variation in the calculation result as the threshold B for the transmission power.
- FIG. It becomes possible to detect a collision of packets as shown in (b), that is, a collision between a part of packets transmitted by the transmission unit 111 and another packet.
- the collision detection process (step S58) based on the average power and the threshold A and the collision detection process (step S63) based on the variation degree and the threshold B are performed.
- the collision detection process based on the average power and the threshold A may not be performed, and only the collision detection process based on the degree of variation and the threshold B may be performed. In this case, even if the power detected by the power detection unit 121 increases due to fluctuation, it is not determined that a packet collision has occurred by mistake.
- the communication device 20 includes a transmission device 21 and a collision detection device 22.
- the transmission device 21 includes a transmission unit 211, a transmission power management unit 212, and an antenna 213.
- the transmission unit 211 has a function of transmitting a packet using the selected communication frequency channel, and a function of transmitting a transmission start signal and a transmission end signal to the collision detection device 22 at the start and end of transmission of the packet. And a setting operation performed by the user, a function of switching transmission power based on the intensity of a signal transmitted from a communication partner, a packet loss rate, and the like.
- the transmission power management unit 212 has a function of transmitting the transmission power of the packet to the power detection unit 221 every time the transmission unit 211 transmits the packet.
- the transmission unit 211 and the transmission power management unit 212 can be realized by a program-controlled CPU.
- the collision detection device 22 includes a power detection unit 221, a collision detection unit 222, a storage device 223, and an antenna 226.
- the storage device 223 is provided with a sampling data storage unit 224 and a threshold storage unit 225.
- sampling data of the power value of the spatial radio signal existing in the frequency band used when the transmission unit 211 transmits the packet, the sampling data sampled during the packet transmission period, and the packet Are recorded in association with each other.
- FIG. 9 is a diagram illustrating an example of the contents of the sampling data storage unit 224.
- the sampling data storage unit 224 in this example has a plurality of rows, and sampling data and transmission power are recorded in each row. For example, it is recorded that the sampling data sampled during the transmission period of the packet P1 is “W1, W2,..., Wn” and the transmission power of the packet P1 is “TP1”.
- the threshold value storage unit 225 stores candidates for the threshold value A used to determine whether or not a packet collision has occurred (See FIG. 4).
- the power detection unit 221 is a spatial radio wave signal present in the frequency band used by the transmission unit 211 for packet transmission in a period from when the transmission start signal is received until the transmission end signal is received (packet transmission period).
- the sampling data storage unit 224 is associated with the function of recording the sampling data (power value) in the sampling data storage unit 224 and the transmission power transmitted from the transmission power management unit 212 in association with the corresponding sampling data. Has the function of recording.
- the collision detection unit 222 performs transmission based on the transmission power transmitted from the transmission power management unit 212, the sampling data recorded in the sampling data storage unit 224, and the threshold value recorded in the threshold storage unit 225. It has a function of determining whether or not a packet transmitted from the device 21 collides with a packet transmitted from another wireless device.
- the power detection unit 221 and the collision detection unit 222 can be realized by a program-controlled CPU.
- the transmission of the packet by the transmission device 21 and the sensing of the spatial radio signal by the collision detection device 22 are performed in synchronization.
- the transmission unit 211 in the transmission device 21 sends a transmission start signal indicating the start of packet transmission to the power detection unit 221 simultaneously with the start of packet transmission.
- the transmission power management unit 212 sends the transmission power at the time of packet transmission to the power detection unit 221 (step S81).
- the power detection unit 221 When receiving the transmission start signal, the power detection unit 221 immediately starts the power sensing process (step S82). In the sensing process, the power detection unit 221 senses the power of the spatial radio wave signal existing in the frequency band used by the transmission unit 211 for packet transmission, and samples the power value at a predetermined sampling frequency. Then, the sampled power value (sampling data) and the transmission power transmitted from the transmission power management unit 212 are associated and recorded in the sampling data storage unit 224 (see FIG. 9).
- the transmission unit 211 transmits a transmission end signal indicating the end of packet transmission to the power detection unit 221 simultaneously with the end of transmission of the packet (step S83). Upon receiving the transmission end signal, the power detection unit 221 immediately ends the power sensing process (step S84). Through the processing from step S81 to S84 described above, the power from the beginning to the end of the packet transmitted by the transmission unit 211 is sensed, and the sampling data is recorded in the sampling data storage unit 224.
- the collision detection unit 222 calculates the average value (average power) of the sampling data for the currently received packet recorded in the sampling data storage unit 224 (step S85).
- the collision detection unit 222 searches the threshold value storage unit 225 for the threshold value recorded in association with the transmission power of the packet received this time, and sets the searched threshold value as the threshold value A used for collision determination (step S86). .
- the collision detection unit 222 compares the average power calculated in step S85 with the threshold determined in step S86 (step S87). If the average power is greater than the threshold A (Yes in step S87), it is determined that a packet collision has occurred (step S88). If the average power is equal to or less than the threshold A (step S87 is No), the collision occurs. Is determined not to occur (step S89).
- the collision detection device identifies the packet transmission period based on the transmission start signal and transmission end signal of the packet sent from the transmission device. This is because it is not necessary to provide a clock on the transmission device side and the collision detection device side in order to specify the packet transmission period as in the above embodiment.
- the sensing period of the power of the spatial radio signal is unnecessarily long. Can be prevented.
- the threshold storage unit 225 uses the threshold storage unit content example 126b shown in FIG. 6 instead of the threshold storage unit content example 126 shown in FIG. Instead, it is realized by executing the processing shown in FIG.
- the communication device 20 first performs the same processing as steps S81 to S87 in FIG.
- step S88 If the average power is greater than the threshold A (Yes in step S87), it is determined that a packet collision has occurred (step S88). On the other hand, when the average power is equal to or less than the threshold A (No in step S87), the threshold B is determined based on the transmission power (step S90). Thereafter, the collision detection unit 222 obtains the degree of variation by performing the calculation shown in the above-described equation (1) (step S91), and compares it with the threshold value B (step S92). If the variation degree is larger than the threshold B (Yes in step S92), it is determined that a packet collision as shown in FIG. 24B has occurred (step S88), and the variation degree is equal to or less than the threshold B. In the case of (No in step S92), it is determined that no packet collision has occurred (step S89).
- the failure detection process (step S92) based on the variation degree and the threshold B is performed. Only the failure detection process based on the threshold value B may be performed.
- the collision detection device specifies the packet transmission period based on the transmission start signal and transmission end signal of the packet sent from the transmission device. This is because it is not necessary to provide a clock on the transmission device side and the collision detection device side in order to specify the packet transmission period as in the above embodiment.
- the sensing period of the power of the spatial radio signal is unnecessarily long. Can be prevented.
- a communication device 30 includes a transmission device 31 and a collision detection unit 32.
- the transmission device 31 includes a transmission unit 311, a transmission power management unit 312, and an antenna 313.
- the transmission unit 311 has a function of transmitting a packet using the selected communication frequency channel, a function of outputting a transmission start signal to the power detection unit 321 before starting transmission of the packet, and power at the end of transmission of the packet. It has a function of outputting a transmission end signal to the detection unit 321 and a function of switching transmission power based on a setting operation performed by a user, the intensity of a signal transmitted from a communication partner, a packet loss rate, and the like.
- the transmission power management unit 312 has a function of notifying the power detection unit 321 of the transmission power of the packet every time the transmission unit 311 transmits the packet.
- the transmission unit 311 and the transmission power management unit 312 can be realized by a program-controlled CPU.
- the collision detection device 32 includes a power detection unit 321, an average value calculation unit 322, a collision detection unit 323, a storage device 324, and an antenna 327.
- the storage device 324 is provided with a sampling data storage unit 325 and a threshold storage unit 326.
- sampling data storage unit 325 the sampling data sampled during the packet transmission period and the packet transmission power are recorded in association with each other in the same manner as the sampling data storage unit 224 described above (see FIG. 9).
- the threshold storage unit 326 records threshold A candidates in association with the transmission powers that the transmission unit 311 can take (see FIG. 4).
- the power detection unit 321 is a frequency used by the transmission unit 311 for packet transmission in the packet transmission period from the reception of the transmission start signal to the reception of the transmission end signal. It has a function of sampling the power of the spatial radio signal existing in the band and a function of recording the sampling data and the transmission power sent from the transmission power management unit 312 in the sampling data storage unit 325 in association with each other.
- the average value calculation unit 322 has a function of calculating an average value of each set by setting N sampling data (N is an integer of 2 or more) adjacent to the sampling data recorded in the sampling data storage unit 325 as one set. Have.
- the collision detection unit 323 has a first threshold value Th1 (Th1) having a value smaller than the lowest transmission power that the transmission unit 311 can take and a value larger than a clear channel assessment (CCA) level. Is constant for one transmission power) and the average value of each of the above sets, and from the average value that first exceeds the first threshold value Th1, the average value that first exceeds the first threshold value Th1 A function for obtaining the average power of the spatial radio signal in the packet transmission period based on the respective average values until, a function for searching the threshold value storage unit 326 corresponding to the threshold value A corresponding to the transmission power of the packet, the average value and the threshold value A function of determining whether or not a packet collision has occurred by comparing A with A.
- Th1 first threshold value having a value smaller than the lowest transmission power that the transmission unit 311 can take and a value larger than a clear channel assessment (CCA) level. Is constant for one transmission power) and the average value of each of the above sets, and from the average value that first exceeds the
- a value (variable value) corresponding to the transmission power of the packet transmitted by the transmission unit 311 may be used, which is smaller than the transmission power of the packet and larger than the clear channel evaluation level. it can.
- a threshold Th1 candidate is recorded in the threshold storage unit 326 in association with each of a plurality of transmission powers that the transmission unit 311 can take, and the collision detection unit 323 transmits the transmission sent from the transmission power management unit 312.
- a candidate recorded in association with power is set as a threshold Th1.
- the power detection unit 321, the average value calculation unit 322, and the collision detection unit 323 can be realized by a program-controlled CPU.
- the transmission unit 311 transmits a transmission start signal to the power detection unit 321 before starting transmission of a packet. Further, the transmission power management unit 312 sends the transmission power of the packet to the power detection unit 321 (step S101).
- the power detection unit 321 When receiving the transmission start signal, the power detection unit 321 immediately starts the sensing process, and associates the sampling data of the power of the sampled spatial radio wave signal with the transmission power transmitted from the transmission power management unit 312 to obtain the sampling data.
- the information is recorded in the storage unit 325 (102).
- the transmission unit 311 transmits a transmission end signal to the power detection unit 321 simultaneously with the end of transmission of the packet (step S103). Thereby, the electric power detection part 321 complete
- the collision detection unit 323 compares the first threshold value Th1 with the average value of each group, and from the average value that first exceeds the first threshold value Th1, Based on each average value up to the average value exceeding the first threshold Th1, the average power of the spatial radio signal in the packet transmission period is calculated (step S106). Next, the collision detection unit 323 searches the threshold storage unit 326 for a threshold value recorded in association with the transmission power of the packet received this time, and sets it as the threshold value A (step S107).
- the collision detection unit 323 compares the average power calculated in Step S106 with the threshold A (Step S108). If the average power is greater than the threshold A (Yes in step S108), it is determined that a packet collision has occurred (step S109). If the average power is equal to or less than the threshold A (No in step S108). It is determined that no collision has occurred (step S110).
- the N sampling data adjacent to each other is set as one set, and an average value for each set is obtained. Further, from the average value that first exceeds the first threshold Th1, the first value is finally added.
- the average power of the spatial radio wave signal in the packet transmission period is calculated based on each average value up to the average value exceeding the threshold value Th1, but first the sampling data exceeding the first threshold value Th1 is the first from the sampling data.
- the average power of the spatial radio signal during the packet transmission period may be calculated based on each sampling data up to the sampling data exceeding the threshold value Th1 of 1.
- the packet transmission period can be specified with higher accuracy by using the average value for each group as in the present embodiment.
- the same effects as those of the first and third embodiments can be obtained. Furthermore, according to the present embodiment, even when the power detection unit cannot start power sensing or end power sensing immediately after receiving a transmission start signal or transmission end signal from the transmission device due to processing delay. The effect that the collision detection accuracy of the packet can be increased can be obtained.
- the reason why the packet collision detection accuracy is increased is that the average power of the spatial radio signal during the packet transmission period can be calculated correctly.
- the reason why the average power of the spatial radio signal during the packet transmission period can be calculated correctly is that the adjacent N sampling data is set as one set to determine the average value for each set, and first exceeds the first threshold Th1. This is because the average power of the spatial radio wave signal in the packet transmission period is calculated based on each average value from the average value to the average value that finally exceeds the first threshold Th1.
- the communication device 30 first performs the same processing as in steps S101 to S108 described above.
- step S109 If the average power is larger than the threshold A (Yes in step S108), it is determined that a packet collision has occurred (step S109). On the other hand, when the average value is equal to or less than the threshold A (No in step S108), a threshold B corresponding to the transmission power is obtained (step S111). Thereafter, the collision detection unit 323 calculates the degree of variation by performing the calculation shown in the above-described equation (1), and compares it with the threshold value B (steps S112 and S113). If the degree of variation is larger (Yes in Step S113), it is determined that a packet collision as shown in FIG. 24B has occurred (Step S109), and if not (No in Step S113). ) Determines that no packet collision has occurred (step S110).
- the collision detection process (step S113) based on the degree of variation and the threshold B is executed. Only the collision detection process based on the variation degree and the threshold B may be performed.
- the same effect as in the second and fourth embodiments can be obtained. Furthermore, according to the present embodiment, even when the power detection unit cannot start power sensing or end power sensing immediately after receiving a transmission start signal or transmission end signal from the transmission device due to processing delay. The effect that the collision detection accuracy of the packet can be increased can be obtained.
- the reason why the packet collision detection accuracy is increased is that the average power of the spatial radio signal during the packet transmission period can be calculated correctly.
- the reason why the average power of the spatial radio signal during the packet transmission period can be calculated correctly is that the adjacent N sampling data is set as one set to determine the average value for each set, and first exceeds the first threshold Th1. This is because the average power of the spatial radio wave signal in the packet transmission period is calculated based on each average value from the average value to the average value that finally exceeds the first threshold Th1.
- the communication device 40 includes a transmission device 41 and a collision detection device 42.
- the transmission device 41 includes a transmission unit 411, an information management unit 412, and an antenna 413.
- the transmission unit 411 has the same function as the transmission unit 311 in the fifth embodiment shown in FIG.
- the information management unit 412 has a function of transmitting transmission parameters including packet transmission power and packet transmission time to the collision detection device 42.
- the transmission time is the time from the start of transmission of one packet to the completion of transmission.
- the transmission unit 411 and the information management unit 412 can be realized by a program-controlled CPU.
- the collision detection device 42 includes a power detection unit 421, an envelope extraction unit 422, a collision detection unit 423, a storage device 424, and an antenna 427.
- the storage device 424 is provided with a sampling data storage unit 425 and a threshold storage unit 426.
- the same information as the sampling data storage unit 325 and the threshold storage unit 326 in the fifth embodiment shown in FIG. 12 is recorded.
- the power detection unit 421 has the same function as the power detection unit 321 in the fifth embodiment shown in FIG.
- the envelope extraction unit 422 has the following functions.
- the first threshold value Th1 that is larger than the clear channel evaluation level, and the second threshold value Th2 that is larger than the threshold value A according to the transmission power of the packet From the time-series data of the average value, a portion where M average values equal to or greater than the first threshold Th1 are continuously detected is detected, and the second continuous value among the average values for each group existing in the detected portion is detected. A function of replacing average values less than the threshold Th2 with those average values and replacing consecutive average values of the second threshold Th2 and higher with those average values.
- the threshold Th2 can be calculated by, for example, multiplying the threshold A corresponding to the transmission power retrieved from the threshold storage unit 426 by a predetermined value greater than 1.
- the collision detection unit 423 has a function of determining whether or not a packet collision has occurred based on the time-series difference data generated by the envelope extraction unit 422.
- the power detection unit 421, the envelope extraction unit 422, and the collision detection unit 423 can be realized by a program-controlled CPU.
- the transmission unit 411 outputs a transmission start signal indicating the start of packet transmission to the power detection unit 421 before starting the packet transmission. Further, the information management unit 412 outputs packet transmission power to the collision detection device 42 (step S131 in FIG. 17). After receiving the transmission start signal, the power detection unit 421 immediately starts sensing processing similar to that described in the third embodiment for the selected frequency band (step S132).
- the selected frequency is the same frequency band as the frequency band used by the transmission unit 411 for packet transmission.
- the transmission unit 411 outputs a transmission end signal indicating the end of packet transmission to the power detection unit 421 simultaneously with the end of transmission of the packet (step S133).
- the power detection unit 421 After receiving the transmission end signal, the power detection unit 421 immediately ends the power sensing process (step S134).
- FIG. 24 shows the relationship between the packet transmitted by the transmission unit 411, the sensing start time, and the sensing end time.
- the information management unit 412 outputs the transmission time required for the transmission unit 411 to transmit the packet to the envelope extraction unit 422 (step S135).
- the envelope extraction unit 422 calculates the number of samplings corresponding to the packet by multiplying the transmission time of the packet by the sampling frequency used by the power detection unit 421 for power sensing (step S136). Further, in step S136, the envelope extraction unit 422 also performs processing for obtaining two positive integers N and M whose multiplication results are the above sampling numbers.
- the sampling frequency used for power sensing is information recorded in the envelope extraction unit 422 in advance. The sampling frequency may be output from the power detection unit 421 to the envelope extraction unit 422 before the power detection unit 421 starts power sensing. Note that the calculation processing of the sampling number in step S136 may be performed by the power detection unit 421.
- the processing result is output to the envelope extraction unit 422. In this case, the transmission time of the packet is output from the transmission unit 411 to the power detection unit 421 in step S135 of FIG.
- the envelope extraction unit 422 performs an envelope extraction process for extracting the envelope information of the signal sensed by the power detection unit 421 based on the sampling data recorded in the sampling data storage unit 425 by the power detection unit 421 (Step S1). S137).
- the outline of the envelope extraction process will be described with reference to FIG. In FIG. 25, the vertical axis represents power and the horizontal axis represents time.
- the envelope extraction unit 422 performs the second average power calculation (B2 in FIG. 25).
- the second average power calculation first, the calculated average value for each set, the first threshold value Th1 that is higher than the clear channel evaluation level, and the second value that is higher than the threshold value A corresponding to the transmission power of the packet.
- a portion where M average values equal to or greater than the first threshold value Th1 are continuously detected is detected from the time series data of the average value for each set.
- the average values less than the second continuous threshold value Th2 are replaced with those average values, and the average values equal to or higher than the second continuous threshold value Th2 are averaged. Replace with value.
- the envelope extraction unit 422 performs the first average power calculation described above (B1 in FIG. 25).
- the second average power calculation (B2 in FIG. 25) will be described with reference to FIG.
- step S1402 the first value (average value) of the time series data of the average value obtained in the first average power calculation is compared with the threshold value Th1 in order (step S1402). If the data value is equal to or greater than the threshold value Th1 (Yes in step S1402), the process proceeds to step S1403. On the other hand, if the data value is smaller than the threshold Th1 (No in step S1402), the process proceeds to step S1413.
- step S1403 If it is determined in step S1403 that the value of the variable S_point is zero (Yes in step S1403), the process proceeds to step S1404. If it is determined in step S1403 that the value of the variable S_point is not zero (step S1403 is No), the process proceeds to step S1405.
- step S1404 the variable S_point is set to the position number of the data currently being processed, and the process proceeds to step S1405.
- An example of the position number is shown in FIG. 25, and is a positive integer representing the order of data in the data string.
- step S1405 the value of the data is compared with a threshold value Th2. If the data value is equal to or greater than the threshold Th2 (Yes in step S1405), the process proceeds to step S1406. On the other hand, when the data value is smaller than the threshold value Th2 in step S1405 (No in step S1405), the process proceeds to step S1409.
- step S1406 it is determined whether or not the variable ES_point is zero. If it is zero (Yes in step S1406), the process proceeds to step S1407. If not (No in step S1406), the process proceeds to step S1408. In step S1407, a position number is set in the variable ES_point, and in step S1408, a position number is set in the variable EE_point. In the next step S1409, the variable Count1 is incremented (+1).
- step S1410 the value of the variable Count1 is compared with the value of M.
- step S1410 If the value of the variable Count1 is M or more (step S1410 is Yes), the process proceeds to step S1414. On the other hand, if it is less than M (No in step S1410), the process proceeds to step S1411.
- step S1411 it is determined whether other data exists behind the data. And when it exists (step S1411 is Yes), it progresses to step S1412. On the other hand, if there is no other data (No in step S1411), the second average power calculation process is terminated.
- step S1412 the next data is processed, and the process proceeds to step S1402.
- Step S1413 when it is determined that the value of the variable Count1 is zero (Yes in Step S1413), the process proceeds to Step S1411. On the other hand, if it is determined in step S1413 that the value of the variable Count1 is not zero (No in step S1413), the process proceeds to step S1414.
- step S1415 the data from the data with the position number S_point to the data with the position number “S_point + Count1-1” is replaced with the average value of the data, and the process proceeds to step S1416.
- step S1416 zero values are given to Count1, S_point, ES_point, and EE_point, and the process proceeds to step S1411.
- step S1417 the values of the variable S_point and the variable ES_point are compared. If they do not match, the data from the position number S_point data to the position number ES_point-1 data is replaced with the average value of the data. On the other hand, if they match, the data from the data having the position number S_point to the data having the position number EE_point is replaced with the average value of the data.
- step S1418 the variable S_point is compared with the variable ES_point. If the two do not match, the data from the data having the position number ES_point to the data having the position number EE_point is replaced with the average value of the data, and the process proceeds to step S1419. On the other hand, if they match, the process proceeds to step S1419.
- step S1419 (S_point + Count1-1) is compared with the variable EE_point. If they do not match, the data from the position number (EE_point + 1) data to the position number (S_point + Count1-1) data is replaced with the average value of the data, and the process proceeds to step S1420. On the other hand, if they match, the process proceeds to step S1420. In step S1420, a value of zero is given to Count1, S_point, ES_point, and EE_point, and the process proceeds to step S1411. The above is the details of the envelope extraction process performed in step S137 of FIG.
- time-series data of average values as shown in FIG. 25 (c) is generated.
- the envelope extraction unit 422 records the generated time series data of the average value in the storage device 424.
- the envelope extraction unit 422 calculates the power of the spatial radio signal as shown in FIG. 25D by taking the difference between adjacent average values in the time series data of the average values as shown in FIG. Time-series difference data indicating the amount of change and the direction of change are generated (step S138).
- Step S139 the collision detection unit 423 performs a collision detection process based on the time-series difference data generated by the envelope extraction unit 422 (step S139). Step S139 in FIG. 17 will be described with reference to FIG.
- the collision detection unit 423 includes the Y pieces of continuous data immediately before the first pulse larger than the threshold Th3 in the time-series difference data shown in FIG. It is determined whether or not zero exists.
- the threshold Th3 can be set to a value (fixed value) that is smaller than the minimum value of the transmission power that the transmission unit 411 can take and larger than the clear channel evaluation level.
- the threshold Th3 is a value (variable value) corresponding to the transmission power of the packet transmitted by the transmission unit 411, and may be a value smaller than the transmission power of the packet and larger than the clear channel evaluation level. .
- candidates for the threshold Th3 are recorded in the threshold storage unit 426 in association with a plurality of transmission powers that the transmission unit 411 can take, and the collision detection unit 423 is sent from the information management unit 412.
- the candidate recorded in association with the transmitted power is set as a threshold Th3.
- Y is set to an appropriate value in consideration of device performance (for example, sampling period) and the number L of elements replaced with 0 in step S1418 in FIG.
- a pulse larger than the threshold Th3 may be referred to as a pulse (+ P), and a pulse smaller than a negative threshold ⁇ Th3 may be referred to as a pulse ( ⁇ P).
- step S151 If it is determined that at least one 0 is present in Y continuous data (Yes in step S151), the process proceeds to step S152. If not, that is, if at least one of the Y consecutive data is not 0 (No in step S151), it is determined that a packet collision has occurred (step S155).
- step S152 at least one 0 exists in the continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time-series difference data shown in FIG. 25 (d). It is determined whether or not.
- Z is set to an appropriate value in consideration of device performance (for example, sampling period) and the number L of elements replaced with 0 in step S1418 in FIG.
- a method of obtaining the first pulse ( ⁇ P) in the time-series difference data a method of actually comparing the pulse and the threshold value ⁇ Th3, or a pulse (+ P) (for example, FIG. It is possible to adopt a method in which the Mth pulse from (d) (6th data) is a pulse (-P) (for example, (11) data in FIG. 25D).
- the processing in steps S151 and S152 can use the result of the first average power calculation (B1 in FIG. 25) or the result of the second average power calculation (B2 in FIG. 25).
- the data that first exceeded the threshold value Th3 in step S152 for example, data (7) in FIG. 25B or data (7) in FIG. 25C) (M ⁇ 1)
- the data for example, data (11) in FIG. 25 (b) or data (11) in FIG. 25 (c)
- Step S152 If it is determined that at least one 0 exists (Yes in Step S152), the process proceeds to Step S153. If not, that is, if at least one is not 0 (No in Step S152), a packet collision occurs. (Step S155).
- the reason why the processes of steps S151 and S152 are performed is as follows. There is a case where the power of the packet of the collision partner is lower than the CCA of the communication apparatus 40 (that is, lower than Th1) and larger than the noise threshold. In this case, there are a collision pattern in which the transmission packet of the communication apparatus 40 collides with the packet of the collision partner transmitted earlier, and a collision pattern in which the packet of the collision partner transmitted later collides. In order to detect these two types of collision patterns, the processes of steps S151 and S152 are performed.
- step S153 the average value of the power of the spatial radio signal during the packet transmission period is calculated based on the time series data of the average value of the power recorded in the storage device 424 by the envelope extraction unit 422. Specifically, among the average values recorded in the storage device 424, the average value corresponding to the first pulse (+ P) larger than the threshold Th3, and the (M ⁇ 1) averages immediately after this average value The average value of the power of the spatial radio signal during the packet transmission period is calculated by adding the value and dividing the addition result by M. For example, the average value time-series data recorded in the storage device 424 is shown in FIG. 25C, and the time-series difference data generated in step S138 in FIG. 17 is shown in FIG.
- the average value of the position number “7” to the average value of the position number “11” in FIG. 25C are added, and the addition result is divided by 5, thereby obtaining the spatial radio signal during the packet transmission period.
- the average value of power is obtained.
- the average value of power can also be obtained as follows. One of the average values recorded in the storage device 424 is greater than the average value corresponding to the pulse ( ⁇ P) currently being processed from the average value corresponding to the pulse (+ P) currently being processed. By adding up to the previous average value and dividing the addition result by M, the average value of the power of the spatial radio signal in the packet transmission period is calculated.
- step S154 the average value of the spatial radio signal in the packet transmission period obtained in step S153 is compared with the threshold value A.
- step S154 If the average power value is larger than the threshold value A (Yes in step S154), it is determined that a packet collision has occurred (step S155). On the other hand, when the average value is equal to or less than the threshold A (No in step S155), the process is terminated.
- step S139 of FIG. 17 the process shown in the flowchart of FIG. 27 may be performed.
- step S181 the collision detection unit 423 has at least one 0 in the continuous Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time-series difference data. It is determined whether or not to do. If it is determined that 0 exists (Yes in Step S181), the process proceeds to Step S182. If not, that is, if at least one is not 0 (No in Step S181), a packet collision occurs. (Step S185).
- step S182 it is determined whether or not at least one 0 exists in the continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time-series difference data. . If it is determined that 0 exists (Yes in Step S182), the process proceeds to Step S183. If not, that is, if at least one is not 0 (No in Step S182), a packet collision has occurred. (Step S185).
- step S183 at least two negative pulses ( ⁇ P) smaller than the negative threshold ⁇ Th3 are continuously included in the data after the positive pulse (+ P) larger than the threshold Th3 in the time series difference data. Determine if it appears.
- step S183 If it is determined that negative pulses appear continuously (Yes in step S183), it is determined that packet collision has occurred (step S185), and if not (step S183 is No), step is performed. The process proceeds to S184. Further, there is no positive pulse (+ P) larger than the threshold Th3 in the data between the at least two negative pulses ( ⁇ P) that appear in succession.
- step S184 a negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 exists in the data after the plus (+ P) larger than the threshold Th3 in the time-series difference data, and the above plus It is determined whether or not the absolute value of the sum of the negative pulse (+ P) and the negative pulse ( ⁇ P) is equal to or greater than the threshold value Th1. If it is determined that the absolute value is equal to or greater than the threshold Th1 (Yes in step S184), it is determined that a packet collision has occurred (step S185), and if not (No in step S184), the process is performed. finish.
- the difference between the collision detection processes shown in FIGS. 19 and 27 is that the collision detection process shown in FIG. 27 can detect a collision from a pulse pattern without using the threshold A.
- process shown in the flowchart of FIG. 20 may be performed as the collision detection process performed in step S139 of FIG.
- step S281 the collision detection unit 423 has at least one 0 in continuous Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time-series difference data. It is determined whether or not to do. If it is determined that 0 exists (Yes in Step S281), the process proceeds to Step S282. If not, that is, if there is not at least one 0 (No in Step S281), a packet collision has occurred. Is determined (step S285).
- step S282 it is determined whether or not at least one 0 exists in the continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time-series difference data. . If it is determined that 0 exists (Yes in step S282), the process proceeds to step S283. If not, that is, if there is no at least one 0 (step S282 is No), a packet collision occurs. Is determined (step S285).
- step S283 from the first data F1 larger than the threshold Th1 in the data calculated in the first average power calculation process shown in FIG.
- the degree of data variation up to the data F2 is calculated. That is, the degree of variation of the average value for each group in the packet transmission period is calculated.
- the degree of variation is calculated by, for example, the above formula (1).
- ⁇ i is the value of the i-th data among the data from the data F1 to the data F2
- ⁇ is the average value of the data from the data F1 to the data F2.
- step S284 the degree of variation obtained in step S283 is compared with the threshold value B corresponding to the transmission power of the packet retrieved from the threshold value storage unit 126b as shown in FIG. If the degree of variation is greater than the threshold value B (Yes in step S284), it is determined that a packet collision has occurred (step S285). On the other hand, when the degree of variation is equal to or less than the threshold value B (No in step S284), the process ends.
- the threshold B corresponding to the transmission power is determined by the collision detection unit 423 before the collision detection process. Specifically, thresholds Thx, Thy, Thz,... For transmission powers W1, W2, W3,... are determined as follows. First, a packet is transmitted from the transmission unit 411 with the transmission power W1 in an environment where there is no spatial radio signal of another radio. Next, by performing the same processing as steps S131 to S137 in FIG. 17 described above, the average value of each group when N pieces of sampling data are grouped is obtained (see FIG. 25B). Thereafter, the degree of variation is calculated by the same method as in step S283 described above. The calculation result Thx is set as a threshold B for the transmission power W1.
- a value obtained by correcting the calculated degree of variation in consideration of environmental noise or the like can be used as the threshold value B.
- the same processing is performed for the other transmission powers W2, W3,... To determine threshold values Thy, Thz,. Note that, for one transmission power, a packet is transmitted a plurality of times with the transmission power, the degree of variation for each time is calculated in step S283, and the maximum degree of variation in the calculation result is set as a threshold B for the transmission power. Can also be adopted.
- the threshold B for one transmission power can be determined using the degree of variation calculated by the processing shown in the flowcharts of FIGS. .
- the packet is transmitted a plurality of times with the transmission power, and the degree of variation for each time is calculated by the processing shown in the flowcharts of FIGS.
- 0 exists in consecutive Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time-series difference data shown in FIG. 25D (Yes in step S291).
- 0 exists in the continuous Z pieces of data immediately after the first pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 (step S292 is Yes), and the pulse (+ P)
- the average value of the data between the pulse ( ⁇ P) is equal to or less than the above-described threshold A (No in steps S293 and S294), and two pulses ( ⁇ P) appear successively after the pulse (+ P).
- Step S295 is No
- the absolute value of the sum of the pulse (+ P) and the pulse ( ⁇ P) is less than the first threshold Th1 (Yes in step S296), between the data F1 and the data F2 Data variation Calculating a slip (step S297).
- Step S291 in FIG. 21 corresponds to Step S151 in FIG. 19 and Step S181 in FIG.
- Step S292 in FIG. 21 corresponds to Step S152 in FIG. 19 and Step S182 in FIG.
- Step S293 in FIG. 19 corresponds to step S153 in FIG. 19
- step S294 in FIG. 21 corresponds to step S154 in FIG.
- step S295 in FIG. 21 corresponds to step S183 in FIG. 27, and step S296 in FIG. This corresponds to 27 step S184. Therefore, the degree of data variation between data F1 and data F2 calculated in step S297 in FIG. 21 indicates the degree of packet variation when no packet collision occurs.
- step S291a when there is no zero in the continuous Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time-series difference data shown in FIG.
- step S291a when there is no zero in the continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time series difference data (step S292a) Is No), when the average value of the data between the pulse (+ P) and the pulse ( ⁇ P) exceeds the threshold A described above (Yes in steps S293 and S294), two pulses (+ P) are followed by ( -P) appears continuously (Yes in step S295a), or the absolute value of the sum of the pulse (+ P) and the pulse (-P) is greater than or equal to the first threshold Th1 (Yes in step S296a) ) Calculates a variation degree of the data between the data F1 and the data F2 (step S297a).
- Step S291a in FIG. 22 corresponds to Step S151 in FIG. 19 and Step S181 in FIG. 27
- Step S292a in FIG. 22 corresponds to Step S152 in FIG. 19 and Step S182 in FIG. 27
- Step S293a in FIG. 19 corresponds to step S153 in FIG. 19
- step S294a in FIG. 22 corresponds to step S154 in FIG. 19
- step S295a in FIG. 22 corresponds to step S183 in FIG. 27, and step S296a in FIG. This corresponds to 27 step S184.
- the degree of data variation between data F1 and data F2 calculated in step S297a in FIG. 22 indicates the degree of packet variation when packet collision occurs.
- FIG. 26 a distribution diagram as shown in FIG. 26 is created to show the distribution of the variation degree at the time of non-collision calculated according to the flowchart of FIG. 21 and the variation degree at the time of packet collision calculated according to the flowchart of FIG.
- the horizontal axis represents the degree of variation
- the vertical axis represents the number.
- the distribution of the variation degree differs between the case where no packet collision occurs and the case where packet collision occurs.
- the number of distributions is the smallest between the peak P1 of the degree of variation when no packet collision occurs and the peak P2 of the degree of variation when packet collision occurs.
- the variation degree is defined as a threshold value B.
- the degree of variation at the center is set as the threshold value B.
- the threshold value B may be determined as follows. Regardless of the presence or absence of packet collision, the degree of variation is calculated for a plurality of packets, and a distribution diagram as shown in FIG. 26 showing the distribution of the calculated degree of variation is created.
- the threshold value B may be determined as follows.
- the degree of variation of a plurality of packets in which no packet collision occurs and the degree of variation of packets of a plurality of collision patterns in FIG. 16 (b) that cannot be completely detected by the processes in steps S293, S294, S295, and S296 are calculated ( The processing of FIG. 21 is executed for a plurality of packets to calculate the degree of variation for the plurality of packets), and a distribution diagram as shown in FIG. 26 showing the distribution of the calculated degree of variation is created. Thereafter, the degree of variation in which the number of distributions becomes the smallest between the two peaks of the degree of variation is obtained, and this is set as the threshold value B.
- the process shown in the flowchart of FIG. 23 may be performed as the collision detection process performed in step S139 of FIG.
- the collision detection process shown in FIG. 23 is a combination of FIG. 19, FIG. 20, and FIG.
- Dotted blocks S3108, S3109, and S3110 shown in FIG. 23 correspond to the collision detection processes of FIGS. 19, 20, and 27, respectively. That is, the dotted block S3108 shown in FIG. 23 corresponds to steps S151 and S152 in FIG. 19, steps S281 and S282 in FIG. 20, and steps S181 and S182 in FIG.
- a block S3109 shown in FIG. 23 corresponds to steps S153 and S154 in FIG.
- a block S3110 shown in FIG. 23 corresponds to steps S283 and S284 in FIG. Note that the processing order of the blocks S3108, S3109, and S3110 may be other than the order shown in FIG.
- the divergence value can be used for the collision detection processing performed in step S139 of FIG.
- the collision detection unit 423 calculates the power average value and the power variation degree of the packet received by the power detection unit 411, compares it with the above reference data, and determines the difference between them. Then, a divergence that is an amount representing an information theoretical gap with respect to the statistical value is calculated. When the divergence value exceeds a certain range, it is determined that there is a collision.
- KL divergence Kullback-Leibler divergence
- Jeffrey divergence Jeffrey divergence
- step S139 of FIG. 17 the process shown in the flowchart of FIG. 28 may be performed.
- the collision detection unit 423 includes a negative pulse smaller than the negative threshold ⁇ Th3 in the data after the first pulse (+ P) larger than the threshold Th3 in the time-series difference data. It is determined whether ( ⁇ P) exists and the interval between the positive pulse (+ P) and the first negative pulse ( ⁇ P) in the subsequent data is equal to M or not. Note that the pulses (+ P) and ( ⁇ P) do not exist between the pulse (+ P) and the pulse ( ⁇ P). If it is determined that the interval is equal to M (Yes in step S191), the process proceeds to step S192. If it is not determined (No in step S191), the process proceeds to step S196.
- the interval between the positive pulse (+ P) and the negative pulse ( ⁇ P) is defined as the difference between the position number of the negative pulse ( ⁇ P) and the position number of the positive pulse (+ P).
- the pulse 101 shown in FIG. 25D is a positive pulse (+ P) larger than the threshold Th3.
- the pulse 102 is a negative pulse (-P) smaller than the negative threshold value -Th3.
- the position number of the pulse 102 is “11”, and the position number of the pulse 101 is “6”. Therefore, the interval between the pulse 102 and the pulse 101 is 5.
- step S196 the second negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 exists in the data after the first pulse (+ P) larger than the threshold Th3 in the time series difference data, and It is determined whether or not the interval between the positive pulse (+ P) and the negative pulse ( ⁇ P) is equal to M. And when it determines with it being equal to M (step S196 is Yes), it progresses to step S194, and when it determines with that is not right (step S196 is No), it progresses to step S197. There is no pulse (+ P) between the first pulse (-P) and the second pulse (-P).
- step S197 it is determined whether or not there is a positive pulse (+ P) larger than the threshold Th3 in the data after the negative pulse ( ⁇ P). And when it determines with existing (step S197 is Yes), it considers the said positive pulse (+ P) as the first positive pulse (+ P) in time series difference data, progresses to step S191, and determines that it is not so. In the case (No in step S197), the collision detection unit 423 ends the collision detection process.
- Steps S192, S193, S194, S195, and S198 are the same as S151, S152, S153, S154, and S155 of FIG. Specifically, in step S192, it is determined whether or not 0 is included in continuous Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time series difference data. When it is determined that 0 is not included (No in step S192), it is determined that a packet collision occurs (step S198), and when it is determined that this is not the case (step S192 is Yes). The process proceeds to step S193.
- step S193 it is determined whether or not 0 is included in continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time-series difference data. If it is determined that 0 is not included (No in step S193), it is determined that a packet collision has occurred (step S198), and if it is not determined (step S193 is Yes), The process proceeds to step S194.
- step S194 based on the time series data of the average value of the power recorded in the storage device 424 by the envelope extraction unit 422, the average value of the power of the spatial radio signal during the packet transmission period is calculated. Specifically, among the average values recorded in the storage device 424, the average value corresponding to the first pulse (+ P) larger than the threshold Th3, and the (M ⁇ 1) averages immediately after this average value The average value of the power of the spatial radio signal during the packet transmission period is calculated by adding the value and dividing the addition result by M. For example, the average value time-series data recorded in the storage device 424 is shown in FIG. 25C, and the time-series difference data generated in step S138 in FIG. 17 is shown in FIG. , The average value of the position number “7” to the average value of the position number “11” in FIG. 25C are added, and the addition result is divided by 5, thereby obtaining the spatial radio signal during the packet transmission period. The average value of power is obtained.
- the average value of power can also be obtained as follows.
- One of the average values recorded in the storage device 424 is greater than the average value corresponding to the pulse ( ⁇ P) currently being processed from the average value corresponding to the pulse (+ P) currently being processed.
- the average value of the power of the spatial radio signal in the packet transmission period is calculated.
- step S195 the average value of the spatial radio signal in the packet transmission period obtained in step S194 is compared with the threshold value A. If the average power value is larger than the threshold value A (Yes in step S195), it is determined that a packet collision has occurred (step S198). On the other hand, when the average value is equal to or less than the threshold A (No in step S195), the process proceeds to step S197.
- steps S201, S206, and S207 are the same as steps S191, S196, and S197 in FIG.
- the collision detection unit 423 includes a negative pulse smaller than the negative threshold ⁇ Th3 in the data after the first pulse (+ P) larger than the threshold Th3 in the time-series difference data. It is determined whether ( ⁇ P) exists and the interval between the positive pulse (+ P) and the first negative pulse ( ⁇ P) in the subsequent data is equal to M or not. There are no pulses (+ P) and ( ⁇ P) between the pulse (+ P) and the pulse ( ⁇ P). And when it determines with it being equal to M (step S201 is Yes), it progresses to step S202, and when it determines with that is not right (step S201 is No), it progresses to step S206.
- step S206 the second negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 exists in the data after the first pulse (+ P) larger than the threshold Th3 in the time series difference data, and It is determined whether or not the interval between the positive pulse (+ P) and the negative pulse ( ⁇ P) is equal to M. And when it determines with it being equal to M (step S206 is Yes), it progresses to step S204, and when it determines with that is not right (step S206 is No), it progresses to step S207. There is no pulse (+ P) between the first pulse (-P) and the second pulse (-P).
- step S207 it is determined whether or not a positive pulse (+ P) larger than the threshold Th3 exists in the data after the negative pulse ( ⁇ P). And when it determines with existing (step S207 is Yes), the said positive pulse (+ P) is considered as the first positive pulse (+ P) in time series difference data, and it progresses to step S201, and it determined that it was not so In the case (No in step S207), the collision detection unit 423 ends the collision detection process.
- Steps S202, S203, S204, S205, and S208 are the same as S181, S182, S183, S184, and S185 in FIG. Specifically, in step S202, it is determined whether or not 0 is included in continuous Y data immediately before the first pulse (+ P) larger than the threshold Th3 in the time-series difference data. If it is determined that 0 is not included (No in step S202), it is determined that a packet collision has occurred (step S208), and if it is determined that this is not the case (step S202 is Yes). The process proceeds to step S203.
- step S203 it is determined whether or not 0 is included in continuous Z data immediately after the first pulse (-P) smaller than the negative threshold -Th3 in the time series difference data. If it is determined that 0 is not included (No in step S203), it is determined that a packet collision has occurred (step S208). If it is determined that this is not the case (step S203 is Yes), Proceed to step S204.
- step S204 at least two negative thresholds ( ⁇ P) smaller than the negative threshold ⁇ Th3 are continuously included in the data after the positive pulse (+ P) larger than the threshold Th3 in the time series difference data. Determine if it appears. If it is determined that negative pulses appear continuously (Yes in step S204), it is determined that a packet collision has occurred (step S208). If not (step S204 is No), step is determined. The process proceeds to S205.
- ⁇ P negative thresholds
- step S205 a negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 exists in the data after the positive pulse (+ P) larger than the threshold Th3 in the time-series difference data, and the above It is determined whether or not the absolute value of the sum of the positive pulse (+ P) and the negative pulse ( ⁇ P) exceeds the threshold Th1. If it is determined that the absolute value is equal to or greater than the threshold value Th1 (Yes in step S205), it is determined that a packet collision has occurred (step S208). If not (step S205 is No), step S207 is performed. Proceed to
- steps S321, S326, and S327 are the same as steps S201, S206, and S207 of FIG.
- steps S322, S323, S324, S325, and S328 correspond to steps S281, S282, S283, S284, and S285 in FIG.
- F1b in step S324 is data having a position number “K1 + 1” in the data calculated in the first average power calculation process.
- K1 is the position number of the positive pulse (+ P) calculated by the power difference calculation process of adjacent data. If the data calculated by the power difference calculation process of adjacent data is as shown in FIG. 25D, the position number of the positive pulse (+ P) is “6”, and F1b is shown in FIG. 25B. This is the seventh data in the data string.
- F2b in step S324 is data whose position number in the data calculated in the first average power calculation process is “K2”.
- K2 is the position number of the minus pulse (-P) calculated in the power difference calculation process of adjacent data.
- the position number of the negative pulse ( ⁇ P) is “11”, and F1b is shown in FIG. This is the eleventh data in the data string shown.
- the interval between the positive pulse (+ P) and the negative pulse ( ⁇ P) is M.
- step S324 the degree of data variation between the data F1b and the data F2b is calculated by the above-described equation (1) or the like.
- step S325 the degree of variation is compared with the threshold value B. If the degree of variation is larger (Yes in step S325), it is determined that a packet collision has occurred (step S328).
- FIG. 24A The difference between the collision detection process shown in FIG. 30 and the collision detection process shown in FIGS. 28 and 29 will be described with reference to FIG. 24A.
- FIG. 24A According to the collision detection process of FIG. 30 that detects packet collision based on the degree of variation and the threshold value B, even when the received power detected by the power detection unit 421 is reduced due to fluctuation, FIG. 24A (b) Can be detected, but the collision detection process shown in FIGS. 28 and 29 cannot detect a packet collision as shown in FIG. 24A (b).
- the collision detection process shown in FIG. 31 is a combination of FIG. 28, FIG. 29 and FIG.
- Dotted blocks S3311, S3312, and S3313 shown in FIG. 31 correspond to the collision detection processes in FIGS. 28, 29, and 30, respectively. That is, steps S3301, S3308, and S3309 in FIG. 31 correspond to steps S3301, S3308, and S3309 in FIG. 28, steps S201, S206, and S207 in FIG. 29, and S321, S326, and S327 in FIG.
- the block S3311 corresponds to steps S192 and S193 in FIG. 28, steps S202 and S203 in FIG.
- a block S3312 shown in FIG. 31 corresponds to steps S194 and S195 in FIG.
- a block S3313 shown in FIG. 31 corresponds to steps S324 and S325 in FIG. Note that the processing order of the block S3311, the block S3312, and the block S3313 may be an order other than the order shown in FIG.
- the collision detection process shown in FIG. 19 and FIG. 27 when a packet is transmitted from another wireless device before the transmission unit 411 transmits a packet after the power detection unit 421 starts power sensing, the transmission unit 411. The packet sent from cannot be determined correctly.
- the collision detection process shown in FIGS. 28 and 29 can solve the above-described problem.
- the difference between the collision detection processes shown in FIGS. 28 and 29 is that the collision detection process shown in FIG. 29 can detect a collision from a pulse pattern without using the threshold A.
- step S131 is replaced with step S211, and steps S134 and S135.
- step S212 is added between and step S213 is added between step S136 and step S137.
- step S137 is added between step S136 and step S137.
- the transmission unit 411 outputs a transmission start signal indicating the start of packet transmission to the power detection unit 421 simultaneously with the start of packet transmission. Further, the information management unit 412 outputs the transmission power of the packet (step S211).
- the power detection unit 421 starts the power sensing process immediately after receiving the transmission start signal (step S132). Depending on the processing capability of the power detection unit 421, until the sensing process starts after the packet transmission is started. In addition, a delay time may occur. In such a case, an undetected portion that has not been sensed (sampled) by the power detection unit 421 occurs at the beginning of the packet transmitted from the transmission unit 411.
- the undetected part of the packet is, for example, the part from d1 to d2 in FIG.
- step S212 the power detection unit 421 calculates the sampling number (unsampling number) corresponding to the undetected part. Specifically, the power detection unit 421 calculates a time interval from the reception time of the transmission signal to the start time of the power sensing process, and multiplies the calculated time interval by the sampling frequency to correspond to the undetected portion. The unsampled number J to be calculated is calculated. The calculated unsampled number J is output to the envelope extraction unit 422.
- step S213 the envelope extraction unit 422 subtracts the unsampling number J corresponding to the undetected part from the sampling number obtained in step S136, and detects the detection sensed by the power detection unit 421 of the packet transmitted to the transmission unit 411. A sampling number K corresponding to the portion is calculated.
- step S137 the values of N and M are adjusted so that the product of N and M becomes the sampling number K calculated by the power detection unit 421.
- step S139 the processing shown in the flowcharts of FIGS. 19 and 27 is performed. However, since there is no data immediately before the positive pulse (+ P), the processing in step S151 in FIG. 19 and step S181 in FIG. 27 is not performed.
- step S231 the transmission unit 411 sets the transmission time and transmission power of one packet to be transmitted from now on or a plurality of packets having the same power and the same transmission time before starting transmission of the packet.
- the data is output to the detection unit 421.
- the power detection unit 421 starts the power sensing process for the selected frequency band (step S232).
- the power detection unit 421 ends the power sensing process after a predetermined constant power sensing time has elapsed, or after receiving a packet transmission time or transmission power from the transmission unit 411 ( Step S233). In addition, when receiving the packet transmission time or transmission power from the transmission unit 411 and stopping the sensing, the power detection unit 421 restarts the sensing process after stopping the sensing process.
- the power detection unit 421 outputs the transmission time of the packet sent from the transmission unit 411 to the envelope extraction unit 422 (step S234).
- Subsequent steps S136 to S139 can be the same as steps S136 to S139 in FIG.
- step S139 in FIG. 34 may be as shown in FIG.
- step S2401 the collision detection unit 423 determines whether there is a positive pulse (+ P) greater than the threshold Th3 in the time-series difference data generated by the envelope extraction unit 422 in step S138 of FIG. Determine whether. If it is determined that it exists (Yes in step S2401), the process proceeds to step S2402, and if it is determined that it does not exist (No in step S2401), the collision detection process ends.
- step S2402 a negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3 exists in the data after the first pulse (+ P) larger than the threshold Th3 in the time series difference data, and the above It is determined whether the interval between the positive pulse (+ P) and the first negative pulse (-P) in the subsequent data is equal to M or not.
- step S2402 determines with it being equal to M (step S2402 is Yes), it progresses to step S2403, and when it determines with that is not right (step S2402 is No), it progresses to step S2407.
- step S2403 it is determined whether or not 0 is included in continuous Y data immediately before the positive pulse (+ P) described in step S2402. If it is determined that 0 is not included (No in step S2403), it is determined that a packet collision has occurred (step S2409), and then the process proceeds to step S2410. On the other hand, if it is determined that 0 is included (Yes in step S2403), the process proceeds to step S2404.
- step S2404 it is determined whether or not 0 is included in continuous Z data immediately after the negative pulse ( ⁇ P) described in step S2402. If it is determined that 0 is not included (No in step S2404), it is determined that a packet collision has occurred (step S2409). If not (Yes in step S2404), the process proceeds to step S2405. move on.
- step S2405 based on the time series data of the average power value recorded in the storage device 424 by the envelope extraction unit 422, the average power value of the spatial radio signal during the packet transmission period is calculated, and the process proceeds to step S2406.
- a specific calculation method is as described in step S194 in FIG.
- step S2406 the average value of power calculated in step S2405 is compared with the threshold A. If the average power value is greater than the threshold value A (Yes in step S2406), it is determined that a packet collision has occurred (step S2409), and the average power value is equal to or less than the threshold value A. When it determines (step S2406 is No), it progresses to step S2410.
- step S2407 it is determined whether or not the negative pulse ( ⁇ P) appears before the positive pulse (+ P) in the data after the negative pulse ( ⁇ P) described in step S2402.
- step S2407 If it is determined that the negative pulse (-P) appears first (Yes in step S2407), the process proceeds to step S2408, and if not (No in step S2407), the process proceeds to step S2410. .
- step S2408 whether the interval between the positive pulse (+ P) described in step S2402 and the second negative pulse ( ⁇ P) in the order of appearance in the subsequent data of this pulse (+ P) is equal to M or not. Determine whether. If it is determined that it is equal to M (Yes in step S2408), the process proceeds to step S2405. If not (No in step S2408), the process proceeds to step S2410.
- step S2410 it is determined whether or not a positive pulse (+ P) larger than the threshold Th3 appears before another negative pulse ( ⁇ P) smaller than the negative threshold ⁇ Th3. If it is determined that it appears first (Yes in step S2410), the process proceeds to step S2402, and if it is not determined (No in step S2410), the collision detection process ends.
- step S139 of FIG. 34 the process shown in the flowchart of FIG. 37 may be performed.
- steps S2501 and S2502 are performed instead of steps S2405 and S2406.
- step S2501 of FIG. 37 in the data after the positive pulse (+ P) described in step S2402, at least two negative pulses ( ⁇ P) smaller than the negative threshold ⁇ Th3 are positive pulses larger than the threshold Th3. It is determined whether or not it appears before (+ P). If at least two negative pulses (-P) appear first (step S2501 is Yes), it is determined that a packet collision has occurred (step S2409), and if not (step S2501 is No) ) Proceeds to step S2502.
- step S2502 it is determined whether or not the absolute value of the sum of the positive pulse (+ P) and the negative pulse ( ⁇ P) described in step S2402 is equal to or greater than a threshold value Th1. If the absolute value is greater than or equal to the threshold Th1 (Yes in step S2502), it is determined that a packet collision has occurred (step S2409), and if not (No in step S2502), the process proceeds to step S2410.
- the collision detection process shown in FIG. 37 is different from the collision detection process shown in FIG. 35 in that the collision detection process shown in FIG. 37 can detect a collision from a pulse pattern without using the threshold A.
- F1b in step S3405 is data whose position number in the data calculated in the first average power calculation process is “K1 + 1”.
- K1 is the position number of the positive pulse (+ P) calculated by the power difference calculation process of adjacent data. If the data calculated by the power difference calculation process of adjacent data is as shown in FIG. 25D, the position number of the positive pulse (+ P) is “6”, and F1b is shown in FIG. 25B. This is the seventh data in the data string.
- F2b in step S3405 is data whose position number in the data calculated in the first average power calculation process is “K2”.
- K2 is the position number of the minus pulse (-P) calculated in the power difference calculation process of adjacent data. If the data calculated by the power difference calculation process of adjacent data is as shown in FIG. 25D, the position number of the negative pulse ( ⁇ P) is “11”, and F1 is as shown in FIG. 25B. This is the eleventh data in the data string shown. Here, the interval between the positive pulse (+ P) and the negative pulse ( ⁇ P) is M.
- FIG. 24A The difference between the collision detection process shown in FIG. 35 and the collision detection process shown in FIG. 37 in the collision detection process shown in FIG. 38 will be described with reference to FIG. 24A.
- FIG. 24A According to the collision detection process of FIG. 38 that detects packet collision based on the degree of variation and the threshold value B, even when the received power detected by the power detection unit 421 is reduced due to fluctuation, FIG. 24A (b) Can be detected, but the collision detection process shown in FIGS. 35 and 37 cannot detect the packet collision shown in FIG. 24A (b).
- the process shown in the flowchart of FIG. 36 may be performed.
- the collision detection process shown in FIG. 36 is a combination of FIG. 35, FIG. 37, and FIG. 36 corresponds to step S2403 and step S2402 in FIG. 35, corresponds to block S3514, step S2405 and step S2406 in FIG. 35, and block S3515 corresponds to step S3405 and step S3406 in FIG. To do.
- the processing order of the blocks S3513, S3514, and S3515 may be other than the order shown in FIG.
- the same effects as those of the first and third embodiments can be obtained. Furthermore, according to the present embodiment, it is possible to obtain an effect that the sensing processing start and end timings in the power detection unit can be made independent of the packet transmission start and transmission end timings of the transmission unit 411. it can. The reason is that the envelope extraction unit calculates the number of sampling data corresponding to the packet based on the transmission time of the packet and the sampling frequency of the power detection unit, and the multiplication result is the calculated number of sampling data.
- a process for obtaining two positive integers N and M a process for calculating an average value for each set by setting N sampling data adjacent to the sampling data sampled by the power detection unit, and for each set calculated above From the time series data of the average value for each group based on the first threshold value Th1 that is larger than the clear channel evaluation level, and the second threshold value that is larger than the threshold value A.
- a portion where M average values are continuously present is detected, and an average value less than the second threshold Th2 among the average values for each set existing in the detected portion is the average value thereof.
- the communication device 70 includes a transmission device 71 and a collision detection device 72.
- the transmission device 71 includes a transmission unit 711, a clock 712, an information management unit 713, a storage device 714, and an antenna 716.
- the storage device 714 includes a transmission parameter storage unit 715.
- the transmission parameter storage unit 715 records transmission parameters including transmission power, transmission start time, transmission end time, and transmission time of each of the plurality of transmitted packets.
- the transmission parameter includes the transmission start time, the transmission end time, and the transmission time, but two of them may be included. That is, the transmission start time can be obtained from the transmission end time and the transmission time, the transmission end time can be obtained from the transmission start time and the transmission time, and the transmission time can be obtained from the transmission start time and the transmission end time. Therefore, it is sufficient to include two of the transmission start time, transmission end time, and transmission time.
- the transmission unit 711 has the same function as the transmission unit 111 in the first embodiment except that the transmission parameter recorded in the transmission parameter storage unit 715 includes the transmission time.
- the clock 712 has a function of displaying the current time.
- the information management unit 713 has a function of reading the transmission parameter for the packet for which the transmission has been completed from the transmission parameter storage unit 715 and transmitting it to the collision detection device 72 after the transmission of the packet by the transmission unit 711 is completed.
- the transmission time is calculated by calculating (transmission end time ⁇ transmission start time).
- the transmission unit 711 and the information management unit 713 can be realized by a program-controlled CPU.
- the collision detection device 72 includes a power detection unit 721, a clock 722, an envelope extraction unit 723, a collision detection unit 724, a storage device 725, and an antenna 728.
- the storage device 725 is provided with a sampling data storage unit 726 and a threshold storage unit 727. Sampling data and sampling time are recorded in the sampling data storage unit 726 in association with each other (see FIG. 3).
- candidates for thresholds A, Th1, and Th3 are recorded in association with a plurality of transmission powers that the transmission unit 711 can take.
- the power detection unit 721 has a function of sampling the power value of the spatial radio wave signal in the frequency band used by the transmission unit 711 for packet transmission and recording the sampling data and the sampling time in association with each other in the sampling data storage unit 726.
- the clock 722 has a function of displaying the current time.
- the envelope extraction unit 723 performs the same processing as described above (the average power calculation shown in FIG. 25, the processing shown in FIG. 18, etc.) for each of the plurality of packets transmitted by the transmission unit 711, and the time series for each packet It has a function of generating difference data.
- the collision detection unit 724 determines whether a packet transmitted from the transmission unit 711 collides with a packet transmitted from another wireless device based on the time-series difference data for each packet generated by the envelope extraction 723. It has the function to do.
- the power detection unit 721, the envelope extraction unit 723, and the collision detection unit 724 can be realized by a program-controlled CPU.
- step S271 a process of matching the time indicated by the clock 712 on the transmission device 71 side with the time indicated by the clock 722 on the collision detection device 72 side is performed (step S271).
- the specific processing content is the same as the processing performed in step S51 described above.
- the power detection unit 721 starts the sensing process (step S272).
- the sensing process the power of the spatial radio signal in the frequency band used by the transmission unit 711 for packet transmission is sampled at a predetermined sampling period, and the sampling data and the sampling time are associated and recorded in the sampling data storage unit 726. .
- the transmission unit 711 transmits a plurality of packets (step S273). At that time, the transmission unit 711 records the transmission parameters (transmission power, transmission start time, transmission end time, transmission time) of each transmitted packet in the transmission parameter storage unit 715.
- the information management unit 713 reads out the transmission parameters for the plurality of packets from the transmission parameter storage unit 715 and transmits them to the collision detection device 72 (step S274).
- the transmission unit 711 When the collision detection unit 724 receives the transmission parameter, the transmission unit 711 performs steps based on the transmission start time and the transmission end time included in the transmission parameter and the sampling time recorded in the sampling data storage unit 726. Sampling data corresponding to each packet transmitted in S273 is extracted. For each packet, the sampling data corresponding to the packet and the transmission power and transmission time of the packet included in the transmission parameter are passed to the envelope extraction unit 723 (step S275). Note that, in order to apply to the collision detection method (for example, S2403 and S2404 in FIG. 25A), a plurality of sampling data before the start position of the sampling data of the transmission packet and a plurality of sampling data after the end position are also extracted simultaneously. (For example, (M ⁇ N) ⁇ 0.03 sampling data before the start position and after the end position are extracted simultaneously).
- the envelope extraction unit 723 multiplies each packet transmitted by the transmission unit 711 in step S273 by the transmission time of the packet and the sampling frequency in the power detection unit 721 to calculate the number of samplings for each packet (step S276).
- step S277 the envelope extraction process described in step S137 described above is performed for each packet described above.
- step S277 for each packet, a process of obtaining two positive integers N and M whose multiplication result is the sampling number is also performed.
- step S278 the same processing as step S138 described above is performed for each packet, and time-series difference data for each packet is generated.
- next step S279 for example, the processing shown in the flowcharts of FIGS. 24 and 25 described above is performed for each packet, and the presence or absence of a collision is determined for each packet.
- the information management unit 713 notifies the collision detection unit 724 (not the transmission start and end times of each packet), the transmission time of the first packet, the transmission end time of the last packet, the transmission power,
- the transmission parameter including the transmission time is transmitted (step S274).
- the collision detection unit 724 receives the transmission parameter
- the transmission unit 711 performs steps based on the transmission start time and transmission end time included in the transmission parameter and the sampling time recorded in the sampling data storage unit 726. Sampling data corresponding to the time period from the start time of the first packet transmitted in S273 to the end time of the last packet is extracted. Then, the extracted sampling data and the transmission power and transmission time of the packet included in the transmission parameter are passed to the envelope extraction unit 723 (step S275).
- the envelope extraction unit 723 multiplies the transmission time of the packet transmitted by the transmission unit 711 in step S273 and the sampling frequency in the power detection unit 721 to calculate the number of packet samplings (step S276).
- the present embodiment in addition to the effects obtained in the first and third embodiments, it is possible to obtain the effect that the presence / absence of collision can be collectively determined for a plurality of packets.
- the reason is that the power detection unit 721 performs sensing processing for each of a plurality of packets transmitted from the transmission unit 711, the envelope extraction unit 723 generates time-series difference data for each packet, and the collision detection unit 724 This is because the presence / absence of packet collision is determined based on each time-series difference data.
- the present embodiment can also obtain an effect that it is not necessary to record the transmission time as in the sixth embodiment. This is because the transmission time is calculated from the transmission start time and the transmission end time.
- communication apparatus 1000 includes transmission section 1100, power detection section 1200, and collision detection section 1300.
- the transmission unit 1100 has a function of transmitting a packet wirelessly.
- the power detection unit 1200 has a function of sampling the power of the spatial radio signal during a packet transmission period in which the transmission unit 1100 transmits a packet at a predetermined period.
- the collision detection unit 1300 has a function of calculating, as an index value, at least one of the average value and the degree of variation of the spatial radio wave signal power during the packet transmission period based on the sampling data obtained by sampling by the power detection unit 1200.
- the collision detection unit 1300 has a function of determining a reference value based on the transmission power of the packet.
- the collision detection unit 1300 has a function of comparing the index value and the reference value to detect the presence or absence of packet collision.
- the transmission unit 1100, the power detection unit 1200, and the collision detection unit 1300 can be realized, for example, by a program-controlled CPU.
- the communication apparatus 1000 operates as follows. First, the transmission unit 1100 transmits a packet wirelessly, and the power detection unit 1200 samples the power of the spatial radio signal during a packet transmission period during which the transmission unit 1100 transmits the packet at a predetermined period.
- the collision detection unit 1300 calculates, based on the sampling data obtained by sampling by the power detection unit 1200, at least one of the average value and the degree of variation of the spatial radio signal during the packet transmission period as an index value.
- the collision detection unit 1300 determines a reference value based on the transmission power of the packet.
- the collision detection unit 1300 compares the index value with the reference value to detect the presence or absence of a packet collision. Specifically, for example, the collision detection unit 1300 detects that there is no packet collision if the index value is larger than the reference value, and detects that there is a packet collision otherwise.
- the present embodiment it is possible to correctly detect the presence or absence of a packet collision even when the transmission power of the transmission apparatus changes. This is because the reference value to be compared with the index value is determined based on the transmission power of the packet.
- a collision detection device that detects a collision between the transmitted packet and another packet in a communication device having a transmission device that wirelessly transmits a packet, A power detector that samples the power of a spatial radio signal in a packet transmission period in which the transmitter is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and a reference value is calculated based on the transmission power of the packet.
- a collision detection apparatus comprising: a collision detection unit that determines and detects the collision of the packet by comparing the index value with the reference value.
- a reference value storage unit that stores the transmission power of the packet and the reference value in association with each other;
- the collision detection unit acquires the transmission power of the packet from the transmission device, and acquires the reference value stored in the reference value storage unit corresponding to the acquired transmission power of the packet .
- the transmission device outputs a transmission start time and a transmission end time of the packet to the collision detection unit, The collision detection unit, wherein the collision detection unit calculates the index value based on the sampling data obtained by the sampling by the power detection unit between the transmission start time and the transmission end time.
- the transmission device outputs a transmission start signal at the start of transmission of the packet, outputs a transmission end signal at the end of transmission of the packet,
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output,
- the collision detection unit is a collision detection device that calculates the index value based on the sampling data obtained by the sampling by the power detection unit.
- the transmission device outputs a transmission start signal before starting transmission of the packet, and outputs a transmission end signal at the end of transmission of the packet
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output,
- the collision detection unit compares a first threshold having a value greater than a clear channel evaluation level with the sampling data obtained by the sampling by the power detection unit, and first exceeds the first threshold.
- a collision detection apparatus that calculates the index value based on each sampling data from the sampling data to the sampling data that has finally exceeded the first threshold.
- the transmission device outputs a transmission start signal before starting transmission of the packet, and outputs a transmission end signal at the end of transmission of the packet
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output
- the average value calculation unit calculates an average value of each set by setting the N sampling data (N is an integer of 2 or more) adjacent to the sampling data obtained by the power detection unit to perform the sampling.
- the collision detection unit compares a first threshold value having a value larger than a clear channel evaluation level with the average value of each set, and from the average value exceeding the first threshold value first, finally the first threshold value.
- a collision detection device that calculates the index value based on each average value up to an average value exceeding a threshold value of 1.
- the transmission device outputs a transmission start signal before starting transmission of the packet, a process of outputting a transmission end signal when transmission of the packet ends, and a transmission time necessary for transmitting the packet Processing and
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output,
- the envelope extraction unit calculates the number of sampling data corresponding to the packet based on the transmission time of the packet and the sampling frequency of the power detection unit, and the result of mutual multiplication becomes the calculated number of sampling data
- the collision detection unit is a collision detection device that calculates the index value and detects the presence or absence of the packet collision based on the time-series difference data generated by the envelope extraction unit.
- the transmission device outputs a transmission start signal at the start of transmission of the packet, outputs a transmission end signal at the end of transmission of the packet, and outputs a transmission time necessary for transmitting the packet
- the power detection unit starts sampling the power of the spatial radio signal by receiving the transmission start signal, ends sampling of the power of the spatial radio signal by receiving the transmission end signal, and transmits the transmission Based on the reception time at which the start signal is received, the sampling start time and the sampling frequency of the spatial radio signal, the number of unsampled data to be sampled in the unsampling period from the reception time to the sampling start time is calculated.
- the envelope extraction unit based on the number of unsampled data calculated by the power detection unit, the transmission time of the packet, and the sampling frequency of the power detection unit, the number of sampling data of the packet portion sampled by the power detection unit A process of calculating two positive integers N and M whose multiplication results are the calculated number of sampling data, and N adjacent sampling data sampled by the power detection unit. A process of calculating the average value for each set with the sampling data as one set, the calculated average value for each set, a first threshold value higher than the clear channel evaluation level, and larger than the first threshold value Based on the second threshold value, a portion in which M average values equal to or greater than the first threshold value are continuously present from the time-series data of the average value for each set.
- the collision detection unit is a collision detection device that calculates the index value and detects the presence or absence of the packet collision based on the time-series difference data generated by the envelope extraction unit.
- An envelope extraction unit In the collision detection apparatus according to appendix 1 or 2, An envelope extraction unit; and The transmitting device outputs a transmission time required to transmit the packet;
- the power detection unit starts sampling the power of the spatial radio signal by receiving the transmission time, ends the sampling of the power of the spatial radio signal at a predetermined timing,
- the envelope extraction unit calculates the number of sampling data corresponding to the packet based on the transmission time of the packet and the sampling frequency of the power detection unit, and the result of mutual multiplication becomes the calculated number of sampling data
- a process for obtaining two positive integers N and M a process for calculating an average value for each set by setting N sampling data adjacent to the sampling data sampled by the power detection unit, and the calculated set Based on the average value for each group, the first threshold value that is greater than the clear channel evaluation level, and the second threshold value that is greater than the first threshold value, A portion where M average values equal to or greater than the threshold value of 1 are continuously present is detected, and an average value less than the second threshold value among the average values of the groups existing
- a power detection unit that samples the power of a spatial radio signal in a packet transmission period in which the transmission unit is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling by the power detection unit, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and based on the transmission power of the packet
- a collision detection unit that determines a reference value and compares the index value with the reference value to detect the presence or absence of collision of the packet.
- a reference value storage unit that stores the transmission power of the packet and the reference value in association with each other;
- the said collision detection part is a communication apparatus which acquires the transmission power of the said packet from the said transmitter, and acquires the said reference value memorize
- the transmission unit outputs a transmission start time and a transmission end time of the packet to the collision detection unit
- the said collision detection part is a communication apparatus which calculates the said index value based on the said sampling data which the said electric power detection part sampled from the said transmission start time to the said transmission end time.
- the transmission unit outputs a transmission start signal at the start of transmission of the packet, outputs a transmission end signal at the end of transmission of the packet,
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output,
- the collision detection unit is a communication apparatus that calculates the index value based on the sampling data obtained by the sampling by the power detection unit.
- the communication apparatus includes a reference value storage unit that stores the transmission power of the packet and the reference value in association with each other, In the determination of the reference value, a collision detection method of acquiring the transmission power of the packet and acquiring the reference value stored in the reference value storage unit corresponding to the acquired transmission power of the packet.
- (Appendix 18) Computer A transmitter for transmitting packets wirelessly; A power detection unit that samples the power of a spatial radio signal in a packet transmission period in which the transmission unit is transmitting the packet at a predetermined period; Based on the sampling data obtained by sampling by the power detection unit, at least one of the average value and the degree of variation of the power of the spatial radio signal in the packet transmission period is calculated as an index value, and based on the transmission power of the packet A program for determining a reference value and comparing the index value with the reference value to function as a collision detection unit that detects the presence or absence of collision of the packet.
- the computer includes a reference value storage unit that stores the transmission power of the packet and the reference value in association with each other,
- the collision detection unit obtains the transmission power of the packet from the transmission device, and obtains the reference value stored in the reference value storage unit corresponding to the acquired transmission power of the packet.
- the transmission unit outputs a transmission start time and a transmission end time of the packet to the collision detection unit,
- the collision detection unit calculates the index value based on the sampling data obtained by the power sampling unit sampling between the transmission start time and the transmission end time.
- the transmission unit outputs a transmission start signal at the start of transmission of the packet, outputs a transmission end signal at the end of transmission of the packet,
- the power detection unit samples the power of the spatial radio wave signal from when the transmission start signal is output until the transmission end signal is output,
- the collision detection unit is a program for calculating the index value based on the sampling data obtained by the sampling by the power detection unit.
- the present invention can be used for packet collision detection in a wireless LAN.
- Communication device 71 ... Transmission device 711 ... Transmission unit 712 ... Timepiece 713 ... Information management unit 714 ... Storage device 715 ... Parameter storage unit 716 ... Antenna 72 ... Collision detection device 721 ... power detector 722 ... Clock 723 ... envelope extracting unit 724 ... collision detection unit 725 ... storage device 726 ... the sampling data storage unit 727 ... threshold storage unit 728 ... antenna
Abstract
Description
そこで、本発明の目的は、送信装置の送信電力が変化する場合、パケットの衝突の有無を正しく検出できない、という課題を解決した衝突検出装置を提供することにある。
無線によりパケットを送信する送信装置を有する通信装置における前記送信されたパケットと他のパケットとの衝突を検出する衝突検出装置であって、
前記送信装置が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する。
パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する。
無線によりパケットを送信する通信装置が実行するパケット衝突検出方法であって、
前記パケットを送信しているパケット送信期間における空間電波信号の電力をサンプリングし、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出し、
前記パケットの送信電力に基づいて基準値を決定し、
前記指標値と前記基準値とを比較して前記パケットと他のパケットとの衝突の有無を検出する。
コンピュータを、
パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
として機能させる。
図1を参照すると、本発明の第1の実施の形態に係る通信装置10は、送信装置11と、衝突検出装置12と、を備える。
・時刻取得要求に応答して情報管理部113から送られてくる送信装置11側の時計112が示す時刻に基づいて、衝突検出装置12側の時計122が示す時刻を時計112が示す時刻と一致させる機能。
・情報管理部113に対して送信パラメータ取得要求を送信する機能。
・送信パラメータ取得要求に応答して情報管理部113から送られてくる送信パラメータと、サンプリングデータ記憶部125に記録されているサンプリングデータ及びサンプリング時刻と、閾値記憶部126に記録されている閾値とに基づいて、送信装置11から送信されたパケットが他の無線機から送信されたパケットと衝突したか否かを判定する機能。
次に、図1~図4,図5を参照して、本実施の形態の動作について詳細に説明する。
本実施の形態によれば、パケットの送信電力が変化する場合であっても、パケットの衝突が発生したか否かについて正しい判定結果を得ることができる。その理由は、パケット送信電力に応じた閾値と、パケット送信期間における空間電波信号の平均電力とを比較することにより、パケットの衝突が発生したか否かを判定しているからである。
次に、本発明の第2の実施の形態について説明する。本実施の形態は、図4に示した閾値記憶部126の代わりに図6に示した閾値記憶部126bを使用し、通信装置10に図5に示す処理の代わりに図7に示す処理を実行させることにより、実現される。
本実施の形態によれば、反射や環境ノイズの影響で、電力検出部121で検出する電力に揺らぎが発生し、電力検出部121で検出される電力が低下した場合であっても、図24(b)に示すようなパケットの衝突、即ち、送信部111が送信したパケットの一部と他のパケットとの衝突を検出することが可能になる。また、本実施の形態では、平均電力と閾値Aとに基づいた衝突検出処理(ステップS58)と、ばらつき度合と閾値Bとに基づいた衝突検出処理(ステップS63)とを行うようにしたが、平均電力と閾値Aとに基づいた衝突検出処理は行わず、ばらつき度合と閾値Bとに基づいた衝突検出処理だけを行うようにしても良い。このようにした場合は、揺らぎにより電力検出部121で検出される電力が増加しても、誤ってパケットの衝突が発生したと判定してしまうことはない。
次に、本発明の第3の実施の形態について説明する。図8を参照すると、本発明の第3の実施の形態に係る通信装置20は、送信装置21と、衝突検出装置22とを備えている。
次に、図8、図9、図10を参照して本実施の形態の動作を詳細に説明する。
本実施の形態によれば、第1の実施の形態で得られる効果に加え、第1の実施の形態よりも構成を簡単なものにすることができるという効果を得ることができる。その理由は、本実施の形態では、送信装置から送られてくるパケットの送信開始信号および送信終了信号に基づいて、衝突検出装置がパケットの送信期間を特定するようにしており、第1の実施の形態のように、パケットの送信期間を特定するために送信装置側および衝突検出装置側に時計を設ける必要がないからである。また、本実施形態によれば、送信装置21によるパケットの送信と衝突検出装置22による空間電波信号のセンシングとは同期して行われるため、空間電波信号の電力のセンシング期間が無駄に長くなるのを防止できる。
次に、本発明の第4の実施の形態について説明する。本実施の形態は、閾値記憶部225は図4に示した閾値記憶部内容例126の代わりに図6に示した閾値記憶部内容例126bを使用し、通信装置20に図10に示す処理の代わりに図11に示す処理を実行させることにより、実現される。
本実施の形態によれば、第2の実施の形態で得られる効果に加え、第2の実施の形態よりも構成を簡単なものにすることができるという効果を得ることができる。その理由は、本実施の形態では、送信装置から送られてくるパケットの送信開始信号および送信終了信号に基づいて、衝突検出装置がパケットの送信期間を特定するようにしており、第2の実施の形態のように、パケットの送信期間を特定するために送信装置側および衝突検出装置側に時計を設ける必要がないからである。また、本実施形態によれば、送信装置21によるパケットの送信と衝突検出装置22による空間電波信号のセンシングとは同期して行われるため、空間電波信号の電力のセンシング期間が無駄に長くなるのを防止できる。
次に、本発明の第5の実施の形態に係る通信装置について説明する。上述した第1の実施の形態では、通信装置10を構成するデバイス機器の性能にばらつきが存在する場合、送信装置11と衝突検出装置12の時計112,122にずれが生じる。また、第3の実施の形態では、電力検出部221が、処理遅延が生じた場合にはそれが原因で送信装置21からの送信開始信号或いは送信終了信号を受けた後に直ちに電力センシング開始或いは電力センシング終了ができない。このような場合、送信部111,211が送信したパケットの送信期間における空間電波信号の平均電力を正しく算出することができず、衝突検出部123,222が上記のパケットの衝突を正しく検出できない可能性がある。これは衝突検出精度の低下に繋がる。本実施の形態は、上記した問題の解決を図るものである。
次に、本実施の形態の動作について図12および図13を参照して詳細に説明する。
本実施の形態によれば、第1及び第3の実施の形態と同様の効果を得ることができる。更に、本実施の形態によれば、電力検出部が、処理遅延が原因で送信装置からの送信開始信号或いは送信終了信号を受けた後に直ちに電力センシング開始或いは電力センシング終了ができない場合であっても、パケットの衝突検出精度を高いものにすることができるという効果を得ることができる。パケットの衝突検出精度が高まる理由は、パケット送信期間における空間電波信号の平均電力を正しく算出できるためである。またパケット送信期間における空間電波信号の平均電力を正しく算出できる理由は、隣接するN個のサンプリングデータを1組にして組毎の平均値を求め、更に、最初に第1の閾値Th1を超えた平均値から、最後に第1の閾値Th1を超えた平均値までの各平均値に基づいて、パケット送信期間における空間電波信号の平均電力を算出するようにしているからである。
次に、本発明の第6の実施の形態について説明する。本実施の形態は、閾値記憶部326の代わりに図6に示す閾値記憶部126bを使用し、通信装置30に図13のフローチャートに示す処理の代わりに図15のフローチャートに示す処理を実行させることにより実現することができる。
本実施の形態によれば、第2及び第4の実施の形態と同様の効果を得ることができる。更に、本実施の形態によれば、電力検出部が、処理遅延が原因で送信装置からの送信開始信号或いは送信終了信号を受けた後に直ちに電力センシング開始或いは電力センシング終了ができない場合であっても、パケットの衝突検出精度を高いものにすることができるという効果を得ることができる。パケットの衝突検出精度が高まる理由は、パケット送信期間における空間電波信号の平均電力を正しく算出できるためである。またパケット送信期間における空間電波信号の平均電力を正しく算出できる理由は、隣接するN個のサンプリングデータを1組にして組毎の平均値を求め、更に、最初に第1の閾値Th1を超えた平均値から、最後に第1の閾値Th1を超えた平均値までの各平均値に基づいて、パケット送信期間における空間電波信号の平均電力を算出するようにしているからである。
次に、本発明の第7の実施の形態に係る通信装置について詳細に説明する。
・乗算結果N×Mが上記算出したサンプリングデータ数と一致するような2つの正の整数N,Mを求める機能。なお、Nはサンプリングデータ数の1%程度とするのが望ましい。
・電力検出部421がサンプリングしたサンプリングデータの隣接するN個のサンプリングデータを1組にして組毎の平均値を算出する機能。
・上記算出した組毎の平均値と、クリアチャネル評価レベルよりも大きい第1の閾値Th1と、パケットの送信電力に応じた閾値Aよりも大きい第2の閾値Th2とに基づいて、上記組毎の平均値の時系列データから、第1の閾値Th1以上の平均値が連続してM個存在する部分を検出し、検出した部分に存在する組毎の平均値の内、連続する第2の閾値Th2未満の平均値をそれらの平均値で置き換え、連続する第2の閾値Th2以上の平均値をそれらの平均値で置き換える機能。なお、閾値Th2は、例えば、閾値記憶部426から検索した送信電力に応じた閾値Aに、1より大きな所定値を乗算することにより算出することができる。
・第1の閾値Th1以上の平均値が連続して(M-1)個以下存在する部分を検出し、検出した部分に存在する組毎の平均値の内、連続する第2の閾値Th2未満の平均値をそれらの平均値で置き換え、連続する第2の閾値Th2以上の平均値をそれらの平均値で置き換える機能。
・置き換え処理が済んだ平均値の時系列データ中の隣接する平均値の差分を取ることにより、空間電波信号の電力の変化量と変化方向とを示す時系列差分データを生成する機能。
次に、本実施の形態の動作について詳細に説明する。
本実施の形態によれば、第1,第2の実施の形態と同様の効果を得られる。更に、本実施の形態によれば、第1,第2の実施の形態に比較して衝突検出精度を高いものにすることができるという効果を得ることができる。その理由は、空間電波信号の電力の変化量と変化方向とを示す時系列差分データを利用してパケットの衝突を検出するようにしているからである。
次に、本発明の第8の実施の形態について説明する。本実施の形態は、図16に示した通信装置40に、図32のフローチャートに示す処理を行わせることにより実現される。
本実施の形態によれば、第1及び第3の実施の形態で得られる効果に加え、パケットの先頭部分を受信できなかった場合でも、パケットの衝突を検出することができるという効果を得ることができる。その理由は、実際に受信したパケット部分に対応するサンプリング数を求め、このサンプリング数を利用して時系列差分データを生成するようにしているからである。
次に、本発明の第9の実施の形態について説明する。本実施の形態は、図16に示した通信装置40に、図34のフローチャートに示す処理を行わせることにより実現される。
本実施の形態によれば、第1及び第3の実施の形態と同様の効果を得ることができる。更に、本実施の形態によれば、電力検出部におけるセンシング処理の開始、終了タイミングを、送信部411のパケットの送信開始、送信終了タイミングに依存しないものにすることができるという効果を得ることができる。その理由は、包絡抽出部が、パケットの伝送時間と前記電力検出部のサンプリング周波数とに基づいて上記パケットに対応するサンプリングデータ数を算出する処理と、乗算結果が前記算出したサンプリングデータ数となる2つの正の整数N,Mを求める処理と、電力検出部がサンプリングしたサンプリングデータの隣接するN個のサンプリングデータを1組にして組毎の平均値を算出する処理と、上記算出した組毎の平均値と、クリアチャネル評価レベルよりも大きい第1の閾値Th1と、閾値Aよりも大きい第2の閾値とに基づいて、上記組毎の平均値の時系列データから、第1の閾値Th1以上の平均値が連続してM個存在する部分を検出し、検出部分に存在する組毎の平均値の内、第2の閾値Th2未満の平均値をそれらの平均値で置き換え、第2の閾値Th2以上の平均値をそれらの平均値で置き換える処理と、置き換え処理が済んだ平均値の時系列データ中の隣接する平均値の差分を取る処理を行うことにより、空間電波信号の電力の変化量と変化方向とを示す時系列差分データを生成するようにしているからである。
次に、本発明の第10の実施の形態に係る通信装置について詳細に説明する。
次に、本実施の形態の動作について、図40のフローチャートを参照して説明する。
本実施の形態によれば、第1および第3の実施の形態で得られる効果に加え、複数のパケットについて、一括して衝突の有無を判定することができるという効果を得ることができる。その理由は、電力検出部721が送信部711から送信された複数のパケットそれぞれについてセンシング処理を行い、包絡抽出部723が上記パケット毎に時系列差分データを生成し、衝突検出部724が上記パケット毎の時系列差分データに基づいてパケットの衝突の有無を判定しているからである。また、本実施の形態は、第6の実施の形態のように、伝送時間を記録しておく必要がないという効果を得ることもできる。その理由は、伝送時間を送信開始時刻と送信終了時刻とから算出するようにしているからである。
次に、本発明の第11の実施の形態に係る通信装置について詳細に説明する。
上記実施形態の一部又は全部は、以下の付記のように記載され得るが、以下には限られない。
無線によりパケットを送信する送信装置を有する通信装置における前記送信されたパケットと他のパケットとの衝突を検出する衝突検出装置であって、
前記送信装置が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する衝突検出装置。
付記1に記載の衝突検出装置において、
前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記衝突検出部は、前記送信装置から前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得する
衝突検出装置。
付記1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始時刻と送信終了時刻とを前記衝突検出部に対して出力し、
前記衝突検出部は、前記送信開始時刻から前記送信終了時刻までの間に前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
衝突検出装置。
付記1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始時に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
衝突検出装置。
付記1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始前に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、クリアチャネル評価レベルよりも大きな値を有する第1の閾値と前記電力検出部によって前記サンプリングして得た前記サンプリングデータとを比較し、最初に前記第1の閾値を超えた前記サンプリングデータから最後に前記第1の閾値を超えた前記サンプリングデータまでの各サンプリングデータに基づいて、前記指標値を算出する
衝突検出装置。
付記1または2に記載の衝突検出装置において、
平均値算出部を有し、
前記送信装置は、前記パケットの送信開始前に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記平均値算出部は、前記電力検出部が前記サンプリングして得た前記サンプリングデータの隣接するN個(Nは2以上の整数)の前記サンプリングデータを1組にして各組の平均値を算出し、
前記衝突検出部は、クリアチャネル評価レベルよりも大きな値を有する第1の閾値と前記各組の平均値とを比較し、最初に前記第1の閾値を超えた平均値から、最後に前記第1の閾値を超えた平均値までの各平均値に基づいて、前記指標値を算出する
衝突検出装置。
付記1または2に記載の衝突検出装置において、
包絡抽出部を備え、
前記送信装置は、前記パケットの送信開始前に送信開始信号を出力する処理と、前記パケットの送信終了時に送信終了信号を出力する処理と、前記パケットを伝送するために必要な伝送時間を出力する処理とを行い、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記包絡抽出部は、前記パケットの伝送時間と前記電力検出部のサンプリング周波数とに基づいて前記パケットに対応するサンプリングデータ数を算出する処理と、互いの乗算結果が前記算出したサンプリングデータ数となる2つの正の整数N,Mを求める処理と、前記電力検出部が前記サンプリングして得た前記サンプリングデータの隣接するN個の前記サンプリングデータを1組にして組毎の平均値を算出する処理と、前記算出した組毎の平均値と、クリアチャネル評価レベルよりも大きい第1の閾値と、該第1の閾値よりも大きい第2の閾値に基づいて、前記組毎の平均値の時系列データから、前記第1の閾値以上の平均値が連続してM個存在する部分を検出し、該検出した部分に存在する組毎の平均値の内、前記第2の閾値未満の平均値をそれらの平均値で置き換え、前記第2の閾値以上の平均値をそれらの平均値で置き換える処理と、置き換え処理が済んだ平均値の時系列データ中の隣接する平均値の差分を取ることにより、前記空間電波信号の電力の変化量と変化方向とを示す時系列差分データを生成する処理とを行い、
前記衝突検出部は、前記包絡抽出部で生成された前記時系列差分データに基づいて、前記指標値の算出と前記パケットの衝突の有無の検出とを行う
衝突検出装置。
付記1または2に記載の衝突検出装置において、
包絡抽出部を備え、
前記送信装置は、前記パケットの送信開始時に送信開始信号を出力する処理と、前記パケットの送信終了時に送信終了信号を出力する処理と、前記パケットを伝送するために必要な伝送時間を出力する処理とを行い、
前記電力検出部は、前記送信開始信号を受信することにより前記空間電波信号の電力のサンプリングを開始し、前記送信終了信号を受信することにより前記空間電波信号の電力のサンプリングを終了し、前記送信開始信号を受信した受信時刻と前記空間電波信号のサンプリングの開始時刻とサンプリング周波数とに基づいて、前記受信時刻から前記サンプリングの開始時刻までの未サンプリング期間においてサンプリングされるべき未サンプリングデータ数を算出し、
前記包絡抽出部は、前記電力検出部で算出された未サンプリングデータ数と前記パケットの伝送時間と前記電力検出部のサンプリング周波数とに基づいて、前記電力検出部がサンプリングしたパケット部分のサンプリングデータ数を算出する処理と、互いの乗算結果が前記算出したサンプリングデータ数となる2つの正の整数N,Mを算出する処理と、前記電力検出部が前記サンプリングした前記サンプリングデータの隣接するN個の前記サンプリングデータを1組にして組毎の平均値を算出する処理と、前記算出した組毎の平均値と、クリアチャネル評価レベルよりも大きい第1の閾値と、該第1の閾値よりも大きい第2の閾値とに基づいて、前記組毎の平均値の時系列データから、前記第1の閾値以上の平均値が連続してM個存在する部分を検出し、該検出した部分に存在する組毎の平均値の内、前記第2の閾値未満の平均値をそれらの平均値で置き換え、前記第2の閾値以上の平均値をそれらの平均値で置き換える処理と、置き換え処理が済んだ平均値の時系列データ中の隣接する平均値の差分を取ることにより、前記空間電波信号の電力の変化量と変化方向とを示す時系列差分データを生成する処理とを行い、
前記衝突検出部は、前記包絡抽出部で生成された前記時系列差分データに基づいて、前記指標値の算出と前記パケットの衝突の有無の検出を行う
衝突検出装置。
付記1または2に記載の衝突検出装置において、
包絡抽出部を備え、且つ、
前記送信装置は、前記パケットを伝送するために必要な伝送時間を出力し、
前記電力検出部は、前記伝送時間を受信することにより前記空間電波信号の電力のサンプリングを開始し、所定のタイミングで前記空間電波信号の電力のサンプリングを終了し、
前記包絡抽出部は、前記パケットの伝送時間と前記電力検出部のサンプリング周波数とに基づいて前記パケットに対応するサンプリングデータ数を算出する処理と、互いの乗算結果が前記算出したサンプリングデータ数となる2つの正の整数N,Mを求める処理と、前記電力検出部がサンプリングしたサンプリングデータの隣接するN個のサンプリングデータを1組にして組毎の平均値を算出する処理と、前記算出した組毎の平均値と、クリアチャネル評価レベルよりも大きい第1の閾値と、該第1の閾値よりも大きい第2の閾値とに基づいて、前記組毎の平均値の時系列データから、前記第1の閾値以上の平均値が連続してM個存在する部分を検出し、該検出した部分に存在する組毎の平均値の内、前記第2の閾値未満の平均値をそれらの平均値で置き換え、前記第2の閾値以上の平均値をそれらの平均値で置き換える処理と、置き換え処理が済んだ平均値の時系列データ中の隣接する平均値の差分を取ることにより、前記空間電波信号の電力の変化量と変化方向とを示す時系列差分データを生成する処理とを行い、
前記衝突検出部は、前記包絡抽出部で生成された前記時系列差分データに基づいて、前記指標値の算出と前記パケットの衝突の有無の検出を行う
衝突検出装置。
パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する通信装置。
付記10に記載の通信装置において、
前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記衝突検出部は、前記送信装置から前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得
する通信装置。
付記10または11に記載の通信装置において、
前記送信部は、前記パケットの送信開始時刻と送信終了時刻とを前記衝突検出部に対して出力し、
前記衝突検出部は、前記送信開始時刻から前記送信終了時刻までの間に前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
通信装置。
付記10または11に記載の通信装置において、
前記送信部は、前記パケットの送信開始時に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
通信装置。
無線によりパケットを送信する通信装置が実行するパケット衝突検出方法であって、
前記パケットを送信しているパケット送信期間における空間電波信号の電力をサンプリングし、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出し、
前記パケットの送信電力に基づいて基準値を決定し、
前記指標値と前記基準値とを比較して前記パケットと他のパケットとの衝突の有無を検出する
衝突検出方法。
付記14に記載の衝突検出方法において、
前記通信装置は、前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記基準値の決定では、前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得する
衝突検出方法。
付記14または15に記載の衝突検出方法において、
前記指標値の算出では、前記パケットの送信開始時刻から送信終了時刻までの間に前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
衝突検出方法。
付記14または15記載の衝突検出方法において、
前記電力のサンプリングでは、前記パケットの送信開始時に前記空間電波信号の電力の前記サンプリングを開始し、前記パケットの送信終了時に前記サンプリングを終了する
衝突検出方法。
コンピュータを、
パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
として機能させるためのプログラム。
付記18に記載のプログラムにおいて、
前記コンピュータは、前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記衝突検出部は、前記送信装置から前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得
するプログラム。
付記18または19記載のプログラムにおいて、
前記送信部は、前記パケットの送信開始時刻と送信終了時刻とを前記衝突検出部に対して出力し、
前記衝突検出部は、前記送信開始時刻から前記送信終了時刻までの間に前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
プログラム。
付記18または19記載のプログラムにおいて、
付記10または11に記載の通信装置において、
前記送信部は、前記パケットの送信開始時に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
プログラム。
11・・・送信装置
111・・・送信部
112・・・時計
113・・・情報管理部
114・・・記憶装置
115・・・送信パラメータ記憶部
116・・・アンテナ
12・・・衝突検出装置
121・・・電力検出部
122・・・時計
123・・・衝突検出部
124・・・記憶装置
125・・・サンプリングデータ記憶部
126・・・閾値記憶部
127・・・アンテナ
20・・・通信装置
21・・・送信装置
211・・・送信部
212・・・送信電力管理部
213・・・アンテナ
22・・・衝突検出装置
221・・・電力検出部
222・・・衝突検出部
223・・・記憶装置
224・・・サンプリングデータ記憶部
225・・・閾値記憶部
226・・・アンテナ
30・・・通信装置
31・・・送信装置
311・・・送信部
312・・・送信電力管理部
32・・・衝突検出装置
321・・・電力検出部
322・・・平均値算出部
323・・・衝突検出部
324・・・記憶装置
325・・・サンプリングデータ記憶部
326・・・閾値記憶部
327・・・アンテナ
40・・・通信装置
41・・・送信装置
411・・・送信部
412・・・送信電力管理部
42・・・衝突検出装置
421・・・電力検出部
422・・・平均値算出部
423・・・衝突検出部
424・・・記憶装置
425・・・サンプリングデータ記憶部
426・・・閾値記憶部
427・・・アンテナ
70・・・通信装置
71・・・送信装置
711・・・送信部
712・・・時計
713・・・情報管理部
714・・・記憶装置
715・・・パラメータ記憶部
716・・・アンテナ
72・・・衝突検出装置
721・・・電力検出部
722・・・時計
723・・・包絡抽出部
724・・・衝突検出部
725・・・記憶装置
726・・・サンプリングデータ記憶部
727・・・閾値記憶部
728・・・アンテナ
Claims (10)
- 無線によりパケットを送信する送信装置を有する通信装置における前記送信されたパケットと他のパケットとの衝突を検出する衝突検出装置であって、
前記送信装置が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する衝突検出装置。 - 請求項1に記載の衝突検出装置において、
前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記衝突検出部は、前記送信装置から前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得する
衝突検出装置。 - 請求項1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始時刻と送信終了時刻とを前記衝突検出部に対して出力し、
前記衝突検出部は、前記送信開始時刻から前記送信終了時刻までの間に前記電力検出部が前記サンプリングして得た前記サンプリングデータに基づいて、前記指標値を算出する
衝突検出装置。 - 請求項1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始時に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、前記電力検出部が前記サンプリングした前記サンプリングデータに基づいて、前記指標値を算出とする
衝突検出装置。 - 請求項1または2に記載の衝突検出装置において、
前記送信装置は、前記パケットの送信開始前に送信開始信号を出力し、前記パケットの送信終了時に送信終了信号を出力し、
前記電力検出部は、前記送信開始信号が出力されてから前記送信終了信号が出力されるまでの間、前記空間電波信号の電力をサンプリングし、
前記衝突検出部は、クリアチャネル評価レベルよりも大きな値を有する第1の閾値と前記電力検出部によって前記サンプリングして得た前記サンプリングデータとを比較し、最初に前記第1の閾値を超えた前記サンプリングデータから最後に前記第1の閾値を超えた前記サンプリングデータまでの各サンプリングデータに基づいて、前記指標値を算出する
衝突検出装置。 - パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
を有する通信装置。 - 請求項6に記載の通信装置において、
前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記衝突検出部は、前記送信装置から前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得
する通信装置。 - 無線によりパケットを送信する通信装置が実行するパケット衝突検出方法であって、
前記パケットを送信しているパケット送信期間における空間電波信号の電力をサンプリングし、
前記サンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出し、
前記パケットの送信電力に基づいて基準値を決定し、
前記指標値と前記基準値とを比較して前記パケットと他のパケットとの衝突の有無を検出する
衝突検出方法。 - 請求項8に記載の衝突検出方法において、
前記通信装置は、前記パケットの送信電力と前記基準値とを対応付けて記憶する基準値記憶部を有し、
前記基準値の決定では、前記パケットの送信電力を取得し、該取得した前記パケットの送信電力に対応して前記基準値記憶部に記憶されている前記基準値を取得する
衝突検出方法。 - コンピュータを、
パケットを無線により送信する送信部と、
該送信部が前記パケットを送信しているパケット送信期間における空間電波信号の電力を所定周期でサンプリングする電力検出部と、
該電力検出部がサンプリングして得たサンプリングデータに基づいて前記パケット送信期間における前記空間電波信号の電力の平均値およびばらつき度合いの少なくとも一方を指標値として算出すると共に、前記パケットの送信電力に基づいて基準値を決定し、前記指標値と前記基準値とを比較して前記パケットの衝突の有無を検出する衝突検出部と
として機能させるためのプログラム。
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015544770A JP6161137B2 (ja) | 2013-10-28 | 2014-09-05 | 衝突検出装置、通信装置、衝突検出方法、及びプログラム |
US15/032,149 US10165603B2 (en) | 2013-10-28 | 2014-09-05 | Collision detection device, communication device, collision detection method, and program |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013-223060 | 2013-10-28 | ||
JP2013223060 | 2013-10-28 | ||
JP2014026462 | 2014-02-14 | ||
JP2014-026462 | 2014-02-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015063993A1 true WO2015063993A1 (ja) | 2015-05-07 |
Family
ID=53003629
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2014/004575 WO2015063993A1 (ja) | 2013-10-28 | 2014-09-05 | 衝突検出装置、通信装置、衝突検出方法、及びプログラム |
Country Status (3)
Country | Link |
---|---|
US (1) | US10165603B2 (ja) |
JP (1) | JP6161137B2 (ja) |
WO (1) | WO2015063993A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016027428A1 (ja) * | 2014-08-19 | 2016-02-25 | 日本電気通信システム株式会社 | 通信装置 |
WO2017154380A1 (ja) * | 2016-03-08 | 2017-09-14 | ソニー株式会社 | 無線通信装置および無線通信方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0964884A (ja) * | 1995-08-24 | 1997-03-07 | Toshiba Corp | 通信システム及びこれに用いる送信機、受信機 |
JP2004193987A (ja) * | 2002-12-11 | 2004-07-08 | Nippon Telegr & Teleph Corp <Ntt> | 無線パケット通信方法および無線パケット通信装置 |
JP2013005097A (ja) * | 2011-06-14 | 2013-01-07 | Nec Commun Syst Ltd | 無線通信機、ネットワーク、無線通信方法およびプログラム |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11252080A (ja) | 1998-02-27 | 1999-09-17 | Fujitsu Ltd | 伝送路インタフェース装置 |
US7567509B2 (en) * | 2002-09-13 | 2009-07-28 | Dialogic Corporation | Methods and systems for jitter minimization in streaming media |
US7599327B2 (en) * | 2004-06-24 | 2009-10-06 | Motorola, Inc. | Method and apparatus for accessing a wireless communication system |
US20080144493A1 (en) * | 2004-06-30 | 2008-06-19 | Chi-Hsiang Yeh | Method of interference management for interference/collision prevention/avoidance and spatial reuse enhancement |
JP2007096902A (ja) | 2005-09-29 | 2007-04-12 | Oki Electric Ind Co Ltd | 無線通信システムのパケット衝突検出方法及び無線通信装置 |
US7558539B2 (en) * | 2005-09-30 | 2009-07-07 | Freescale Semiconductor, Inc. | Power control feedback loop for adjusting a magnitude of an output signal |
DK3094123T3 (da) * | 2006-03-21 | 2020-01-20 | Ericsson Telefon Ab L M | Målingsunderstøttet dynamisk frekvensgenanvendelse i cellulære telekommunikationsnetværk |
JP4847392B2 (ja) * | 2006-05-29 | 2011-12-28 | 富士通株式会社 | 通信システム、その送信機、受信機、通信方法 |
JP4435146B2 (ja) | 2006-12-28 | 2010-03-17 | 株式会社東芝 | 通信装置 |
US20100195553A1 (en) * | 2008-03-18 | 2010-08-05 | Myers Theodore J | Controlling power in a spread spectrum system |
US7916067B2 (en) * | 2009-02-11 | 2011-03-29 | The Boeing Company | Removing clutter from radar cross section measurements using spectral tagging |
US9144083B2 (en) * | 2011-02-01 | 2015-09-22 | Dynamic Invention Llc | Cooperative sensing scheduling for energy-efficient cognitive radio networks |
ES2614902T3 (es) * | 2011-03-21 | 2017-06-02 | Koninklijke Philips N.V. | Cálculo de la pérdida de potencia en la transmisión inductiva de potencia |
-
2014
- 2014-09-05 WO PCT/JP2014/004575 patent/WO2015063993A1/ja active Application Filing
- 2014-09-05 JP JP2015544770A patent/JP6161137B2/ja active Active
- 2014-09-05 US US15/032,149 patent/US10165603B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0964884A (ja) * | 1995-08-24 | 1997-03-07 | Toshiba Corp | 通信システム及びこれに用いる送信機、受信機 |
JP2004193987A (ja) * | 2002-12-11 | 2004-07-08 | Nippon Telegr & Teleph Corp <Ntt> | 無線パケット通信方法および無線パケット通信装置 |
JP2013005097A (ja) * | 2011-06-14 | 2013-01-07 | Nec Commun Syst Ltd | 無線通信機、ネットワーク、無線通信方法およびプログラム |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016027428A1 (ja) * | 2014-08-19 | 2016-02-25 | 日本電気通信システム株式会社 | 通信装置 |
US10356844B2 (en) | 2014-08-19 | 2019-07-16 | Nec Communication Systems Ltd. | Communication device |
WO2017154380A1 (ja) * | 2016-03-08 | 2017-09-14 | ソニー株式会社 | 無線通信装置および無線通信方法 |
CN108702794A (zh) * | 2016-03-08 | 2018-10-23 | 索尼公司 | 无线通信设备和无线通信方法 |
JPWO2017154380A1 (ja) * | 2016-03-08 | 2019-01-10 | ソニー株式会社 | 無線通信装置および無線通信方法 |
US11219030B2 (en) | 2016-03-08 | 2022-01-04 | Sony Corporation | Wireless communication device and wireless communication method |
Also Published As
Publication number | Publication date |
---|---|
US10165603B2 (en) | 2018-12-25 |
JP6161137B2 (ja) | 2017-07-12 |
US20160262049A1 (en) | 2016-09-08 |
JPWO2015063993A1 (ja) | 2017-03-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6792148B2 (ja) | 無線解析装置、及び無線解析方法 | |
WO2019184557A1 (zh) | 定位根因告警的方法、装置和计算机可读存储介质 | |
US20150131445A1 (en) | Similarity matching method and related device and communication system | |
WO2015172657A1 (en) | System and method for anomaly detection | |
CN106301649B (zh) | 网络中设备间自适应时钟/时间同步系统和方法 | |
Shahzad et al. | Expecting the unexpected: Fast and reliable detection of missing RFID tags in the wild | |
US11251652B2 (en) | Wireless energy transmission method and device | |
US9680719B2 (en) | Communication system, client terminal, and server | |
CN108460346B (zh) | 指纹识别方法及装置 | |
US10277081B2 (en) | Wireless energy transmission method and detection device | |
JP6161137B2 (ja) | 衝突検出装置、通信装置、衝突検出方法、及びプログラム | |
JP6801564B2 (ja) | パラメータ確定方法、干渉分類識別方法及びその装置 | |
JP6992039B2 (ja) | テストデータ作成システムおよびテストデータ作成方法 | |
CN111064716B (zh) | 消息转换方法、装置、存储介质及服务器 | |
US20170034859A1 (en) | Operating environment setting system of electronic device, operating environment setting method and operating environment setting program | |
CN110784336A (zh) | 基于物联网的多设备智能定时延时场景设置方法及系统 | |
JP2016017793A (ja) | 無線測位装置、無線測位方法、無線測位システム、及び、コンピュータ・プログラム | |
US20180176050A1 (en) | Radio analyzer and detecting method | |
CN103245828B (zh) | 功率管理系统和功率管理方法 | |
CN109117020B (zh) | 触控位置的定位方法及装置、存储介质、电子装置 | |
CN111315026A (zh) | 信道的选择方法、装置、网关及计算机可读存储介质 | |
Alhamoud et al. | Evaluation of user feedback in smart home for situational context identification | |
JP2016165064A (ja) | 識別装置、識別方法及び識別装置のプログラム | |
JP7443759B2 (ja) | 位置推定装置、位置推定方法、プログラム及び位置推定システム | |
US11429501B2 (en) | Device, method and non-transitory tangible machine-readable medium for traffic monitoring |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 14859140 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2015544770 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 15032149 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 14859140 Country of ref document: EP Kind code of ref document: A1 |