JP2008219604A - Wireless communication apparatus and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus and a wireless communication system in which the effect of user interference or multi-bus interference is reduced, hardware is simplified and broadcast transmission is also possible. <P>SOLUTION: The present invention relates to a wireless communication apparatus which performs wireless communication on a plurality of channels of different frequencies, comprising a timer 15 which clocks a time and a control section 12a which controls communication so as to alternately repeat a predetermined communication period for performing communication by transmitting and receiving one or more frames and a predetermined channel switching period for switching from a channel used at present to the other channel among the plurality of channels, wherein the control section 12a includes a channel switching section 13 for being switched from the channel used at present to the other channel among the plurality of channels in accordance with a predetermined pattern during the predetermined channel switching period. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio communication apparatus and a radio communication system that reduce the influence of inter-user interference and multipath interference and perform radio communication using a specific low-power radio.

  Conventionally, there is a specific low-power radio as wireless communication that can be operated without a license. The specific low power radio can ensure communication quality even at a communication distance of 100 m indoors or more than 300 m outdoors. In the specific low-power radio, a plurality of narrow-band channels are provided for each communication device, and data communication is performed by using a single frequency. At that time, the specific low-power radio is specified to determine whether or not a radio carrier exists in a frequency band to be transmitted before transmission, and to perform transmission only when it does not exist.

  Here, as a problem when a single frequency is used, there are problems of inter-user interference and multipath interference. Inter-user interference is that multiple users cannot communicate with each other when they use the same frequency. In addition, multipath interference is a situation in which a plurality of wireless communication paths exist between communication devices that perform communication, and radio waves passing through the plurality of wireless communication paths are combined so as to cancel each other, and communication cannot be performed.

  In general, in a wireless communication system in which a broadband wireless frequency is given to one communication device such as a mobile phone or a wireless LAN, the problem of inter-user interference and multipath interference is solved by using spread spectrum. In Patent Document 1, it is possible to incorporate in a wireless terminal, easily remove an interference signal from another station signal, and remove a signal component of the other station that acts as noise in the spread spectrum communication system. An interference canceller is described that can improve the characteristics and increase the number of simultaneous communication stations.

  The interference canceller includes a synchronization circuit that detects a spread code of a desired signal and a carrier wave signal from each station based on the received spread spectrum signal, and a spread code of the desired signal output by the received spread spectrum signal and the synchronization circuit. A multiplication circuit that multiplies the output from the multiplication circuit and the carrier signal from each station that is output from the synchronization circuit, the multiplication result from the synchronization detection circuit, and the spreading code of the desired signal, Correlation value calculation circuit that calculates the interference noise component of each undesired signal based on the correlation value of the signal, a tap coefficient control circuit that calculates the tap coefficient from the phase information of the carrier signal from each station, and the interference obtained by the correlation value calculation circuit An interference generator that obtains a composite component based on the noise component and the tap coefficient obtained by the tap coefficient control circuit, and a rare noise obtained by the correlation value calculation circuit. And a subtracting circuit for obtaining a desired received signal combining component by subtracting obtained by the interference generating unit from the correlation value for the signal.

According to this interference canceling apparatus, it can be incorporated into a mobile terminal and can easily remove interference signals from other station signals, and also remove signal components of other stations that act as noise in spread spectrum communication systems. In addition, noise resistance can be improved and the number of simultaneous communication stations can be increased.
JP 2002-16511 A

  However, the specific low-power radio is a communication method with a narrow band for each channel. Therefore, the direct spread method in which a digital signal is distributed over a wide band with very small power and transmitted at the same time among spread spectrums cannot be used because it requires a wide occupied band. In addition, there is a transmission interval restriction in a specific low power radio channel. Therefore, among the spread spectrum systems, the frequency hopping system cannot be used because it may return to the same frequency within 2 seconds.

  In a specific low power radio in which a plurality of systems coexist and there are many systems that occupy one channel, it is difficult to use a system with low channel use efficiency such as a spread spectrum system.

  In addition, it is difficult to use a spread spectrum method that is inexpensive and uses a specific low power radio for battery-powered equipment and that requires complex processing and high-speed processing.

  Furthermore, in the specific low-power radio, there is also a system that normally uses one frequency and changes the frequency only when a communication abnormality occurs. However, with this method, it is difficult to synchronize the frequency between the transmission side and the reception side. Further, if the number of communication devices increases, it becomes more difficult to synchronize between communication devices, so that it becomes difficult to perform broadcast communication.

The present invention solves the above-described problems of the prior art. A wireless communication device and a wireless communication system that reduce the influence of inter-user interference and multi-bus interference, have simple hardware, and can perform broadcast transmission. The issue is to provide.

  In order to solve the above-described problems, a first aspect of the present invention is a wireless communication apparatus that performs wireless communication using a plurality of channels having different frequencies, the timer for measuring time, and the timer A predetermined communication period for performing communication by transmitting and receiving one or more frames based on the time information timed by and a predetermined for switching from the currently used channel of the plurality of channels to another channel Control means for controlling communication so as to alternately repeat the channel switching period, and the control means is a currently used channel among the plurality of channels according to a predetermined pattern during the predetermined channel switching period. And a channel switching section for switching from one channel to another.

  In order to solve the above-described problems, a second aspect of the present invention provides a wireless communication system comprising a plurality of wireless communication devices according to any one of claims 1 to 7, and the plurality of wireless communication devices. Are wireless communication systems having one or more communication groups that communicate with each other, wherein each of the control means of the plurality of wireless communication devices in the same communication group has the communication period and the channel switching period at the same timing. And each of the channel switching units of the plurality of wireless communication devices in the same communication group is controlled according to the same pattern during the predetermined channel switching period. It is characterized by switching from the currently used channel to another channel.

  A third invention is a wireless communication system comprising a plurality of wireless communication devices according to claim 3 or claim 4 or claim 6 and comprising at least one communication group with which the plurality of wireless communication devices communicate with each other. Thus, each of the plurality of control means includes a communication frequency of the first communication group in which two different communication groups, a first communication group whose communication frequency is approaching and a second communication group whose communication period starts, are close to each other. It is characterized in that the communication period is controlled so that communication is performed using the same channel at the time when the time drops.

  A fourth invention is a wireless communication system comprising a plurality of wireless communication devices according to any one of claims 5 to 7 and having at least one communication group in which the plurality of wireless communication devices communicate with each other. And each of the control means of the plurality of wireless communication devices in the same communication group controls communication so as to alternately repeat the communication period and the channel switching period at the same timing, It is characterized by changing the length for each channel.

  According to the first aspect of the present invention, even when a specific channel is occupied by another communication system or the like, communication can be performed by switching to another channel, and the influence of inter-user interference can be reduced. Can be reduced. Moreover, the influence of multipath interference can be reduced by using a plurality of channels.

  According to the second aspect of the present invention, each of the plurality of wireless communication devices in the same communication group alternately repeats the communication period and the channel switching period at the same timing, and the same during the predetermined channel switching period. Since the currently used channel of the plurality of channels is switched to another channel according to the pattern, the same effect as that of the first invention can be obtained.

  According to the third aspect of the present invention, each of the plurality of control means includes two communication groups, a first communication group whose communication frequency is close to the end of the communication period and a second communication group in which the communication period starts. However, since communication is performed using the same channel when the communication frequency of the first communication group decreases, the limited channel can be used efficiently.

  According to the fourth aspect of the present invention, each of the control means including the synchronization data generation unit of the plurality of wireless communication devices in the same communication group alternately repeats the communication period and the channel switching period at the same timing. In addition, since the communication is controlled and the length of the communication period is changed for each channel, even when there are unsynchronized wireless communication apparatuses in the same communication group, synchronization can be achieved efficiently.

  Embodiments of a wireless communication apparatus and a wireless communication system according to the present invention will be described below in detail with reference to the drawings.

  First, Example 1 will be described with reference to FIGS. 1 is a diagram illustrating a configuration of a wireless communication apparatus and a wireless communication system according to a first embodiment of the present invention. This wireless communication system includes a communication group 1 and a communication group 2, and a plurality of wireless communication devices in each communication group communicate with each other. The communication group 1 includes a communication device 10a, a communication device 20, a communication device 30, and a communication device 40. The communication group 2 includes a communication device 50, a communication device 60, a communication device 70, and a communication device 80. Each communication device corresponds to the wireless communication device of the present invention, all have the same configuration, communicate with each other within the same communication group, and do not communicate with communication devices in other communication groups. That is, a communication group is a group of communication devices that communicate with each other or perform broadcast communication. In this embodiment, there are two communication groups, but there may be one or more than three.

  The communication device 10a corresponds to the wireless communication device of the present invention, and includes a control unit 12a, a timer 15, a memory 16, a frequency generation unit 17, a transmission unit 18, and a reception unit 19, and a plurality of channels having different frequencies. Wireless communication with Other communication devices have the same configuration as the communication device 10a.

  The timer 15 measures time.

  The control unit 12a corresponds to the control means of the present invention, and based on the time information timed by the timer 15, a predetermined communication period for performing communication by transmitting and receiving one or more frames, and among a plurality of channels Communication is controlled so as to alternately repeat a predetermined channel switching period for switching from the currently used channel to another channel.

  The control unit 12a also includes a channel switching unit 13 that switches from the currently used channel to another channel among a plurality of channels according to a predetermined pattern during a predetermined channel switching period. The channel switching unit 13 outputs a channel switching signal to the frequency generation unit 17.

  The memory 16 corresponds to the storage means of the present invention, and communication period information for representing a predetermined communication period, channel switching period information for representing a predetermined channel switching period, and pattern information for representing a predetermined pattern And remember.

  The frequency generation unit 17 changes the frequency according to the channel switching signal output from the channel switching unit 13 and controls the frequency so that transmission / reception can be performed on an appropriate channel via the transmission unit 18 and the reception unit 19. .

  Each of the control means of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 controls communication so that the communication period and the channel switching period are alternately repeated at the same timing, and the communication Each of the channel switching units of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the group 1 is currently used among a plurality of channels according to the same pattern during a predetermined channel switching period. To switch to another channel.

  In addition, each of the control units of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 communicates with a different communication group (here, communication group 2) using the same channel. The communication period is controlled not to be performed.

  FIG. 2 is a diagram illustrating an operation of the communication group 1 according to the present embodiment when viewed from the channel. Here, the memory 16 stores communication period information for a communication period of 4 seconds, channel switching period information for a channel switching period of 1 second, and pattern information for using two channels alternately. Also, the no-signal period (rest period) in FIG. 2 indicates a channel switching period for switching channels. Therefore, each of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 performs communication by alternately using two channels every 5 seconds.

  Each of the control means of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 communicates so as to alternately repeat the communication period of 4 seconds and the channel switching period of 1 second at the same timing. In addition, each of the communication device 10a, the communication device 20, the communication device 30, and the channel switching unit of the communication device 40 in the communication group 1 has the same pattern (two channels alternately) during the channel switching period of 1 second. Use) to switch from the currently used channel of the two channels to another channel. Here, among the plurality of communication devices in the communication group 1, only the communication device that desires communication communicates during the communication period. In addition, the same communication device or a plurality of different communication devices in the same communication group can transmit a plurality of frames during the communication period.

  FIG. 3 is a diagram illustrating an operation of communication control of the communication group 1 according to the present embodiment when viewed from the communication group, and is similar to the operation illustrated in FIG. The channel switching period (rest period) is indicated by hatching. It can be seen that the communication group 1 uses channel 1 and channel 2 alternately every 5 seconds as a whole.

  FIG. 4 is a diagram illustrating an operation of the communication group 1 and the communication group 2 in the present embodiment when viewed from the channel. Here, as described with reference to FIG. 2, the memory 16 has a pattern in which communication period information with a communication period of 4 seconds, channel switching period information with a channel switching period of 1 second, and two channels are used alternately. Memorize information. The same applies to memories included in other communication devices in the communication group 1 and memories included in communication devices in the communication group 2.

  Each of the control means of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 communicates so as to alternately repeat the communication period of 4 seconds and the channel switching period of 1 second at the same timing. In addition, each of the communication device 10a, the communication device 20, the communication device 30, and the channel switching unit of the communication device 40 in the communication group 1 has the same pattern (two channels alternately) during the channel switching period of 1 second. Use) to switch from the currently used channel of the two channels to another channel.

  In addition, each of the control units of the communication device 10a, the communication device 20, the communication device 30, and the communication device 40 in the communication group 1 communicates with a different communication group (here, communication group 2) using the same channel. The communication period is controlled not to be performed. Here, it is possible to avoid using the same channel at the same time by using the two channels so that the use periods do not overlap each other. A method for synchronizing each communication group will be described later.

  FIG. 5 is a diagram illustrating an operation of the communication group 1 and the communication group 2 in the present embodiment when viewed from each communication group, and is similar to the operation illustrated in FIG. Communication group 1 and communication group 2 use channel 1 and channel 2 alternately every 5 seconds as a whole, and two channels are exchanged between communication group 1 and communication group 2 at a constant cycle. I understand that.

  FIG. 6 is a diagram illustrating an operation of the communication control of each communication group when viewed from the channel when the wireless communication system according to the present embodiment has N communication groups. Each communication group performs communication using N channels in order every T seconds as a whole. Since N communication groups perform communication by sequentially switching N channels every T seconds, it is possible to avoid performing communication using the same channel at the same time as different communication groups.

  FIG. 7 is a diagram illustrating the operation of the communication control of each communication group when the wireless communication system according to the present embodiment has N communication groups as viewed from each communication group, and is the same as the operation illustrated in FIG. . Each communication group switches the channel every T seconds as a whole.

  Next, the operation of the present embodiment configured as described above will be described. FIG. 8 is a flowchart illustrating communication control of the control unit 12a in the wireless communication apparatus and wireless communication system according to the present embodiment. First, the control unit 12a sets the channel to 1 using the channel switching unit 13 (step S101). Of course, the control unit of another communication device in the same communication group selects another channel at the same timing.

  Next, the control part 12a starts a communication period (step S103). The communication device 10a can perform communication if necessary during the communication period.

  Next, the control unit 12a determines whether or not a predetermined communication period for performing communication by transmitting and receiving one or more frames has elapsed based on the time information measured by the timer 15 (step S105). Here, the control unit 12a acquires communication period information indicating how long the communication period is from the memory 16. When the predetermined communication period has not elapsed, the control unit 12a returns to step S103 and continues the communication.

  When the predetermined communication period has elapsed, the control unit 12a uses the channel switching unit 13 to switch to a channel obtained by adding 1 to the current channel (step S107). If the current channel is 1, since 1 + 1 = 2, switch to channel 2.

  Next, the control unit 12a determines whether or not the switched channel is the same as n + 1 (step S109). n is the total number of channels, and is stored in the memory 16 as pattern information. In this embodiment, since the number of channels is 2, n is 2. Therefore, the control unit 12a determines whether or not the channel is 3. When the channel is 3, the control unit 12a returns to step S101 and sets the channel to 1 again. When the channel is not 3, the process returns to step S103, and the control unit 12a starts the communication period again.

  Steps S107 and S109 (including step S101 when returning to step S101) are performed during a predetermined channel switching period. Based on the time information measured by the timer 15, the control unit 12a controls the channel switching unit 13 so that the channel switching is completed during the channel switching period. At this time, the control unit 12a acquires channel switching period information indicating how long the channel switching period is from the memory 16.

  As described above, according to the wireless communication apparatus according to the first embodiment of the present invention, even when a specific channel is occupied by another communication system or the like, communication is performed by switching to another channel. And the influence of interference between users can be reduced. Moreover, the influence of multipath interference can be reduced by using a plurality of channels.

  Moreover, since the memory 16 which memorize | stores communication period information, channel switching period information, and pattern information is provided, the user can control a communication form freely by rewriting each information.

  Further, according to the wireless communication system according to the first embodiment of the present invention, each of the plurality of wireless communication devices in the same communication group alternately repeats the communication period and the channel switching period at the same timing, In the channel switching period, switching from the currently used channel to another channel is performed according to the same pattern, so that the influence of inter-user interference and multipath interference can be reduced.

  In addition, since the communication period is controlled so as not to perform communication using the same channel with different communication groups at the same time, a plurality of communication groups can efficiently communicate with a limited number of channels.

  FIG. 9 is a diagram illustrating an operation of the communication control of each communication group as seen from the channel when the wireless communication system according to the second embodiment of the present invention has four communication groups and the number of channels is three. . The configuration in the present embodiment is the same as that in the first embodiment. However, it is assumed that the number of communication groups is four. A plurality of wireless communication devices having the same configuration as that of the communication device 10a are provided in each of the communication groups.

  Each of the plurality of control means controls the communication period so that different communication groups shift the communication period from each other so that each channel is always used by any one of the communication groups.

  Take the communication device 10a in the communication group 1 as an example. The memory 16 stores communication period information having a communication period of 3 T seconds, channel switching period information having a channel switching period of T seconds, and pattern information of repeatedly using three channels in order. In FIG. 9, there is no signalless period (rest period). As shown in FIG. 9, by shifting the communication period of each communication group by T seconds, four communication groups can communicate with each other using three channels.

  In this embodiment, the communication period is three times the channel switching period, and four communication groups communicate. This is generalized as follows.

  Let P be the time of the communication period when the time of the channel switching period is 1. When P is an integer, it is most efficient when (P + 1) communication groups communicate using the P channel. Further, control is performed so that the communication group (X-1) performs communication immediately after the communication period of the communication group X in the same channel. Here, after the communication group 1, the communication group (P + 1), which is the maximum group number, performs communication. Furthermore, if P is not an integer, there are two methods.

  First, Q is calculated such that (P × Q) is an integer (preferably the minimum), (P × Q) channels are used, and ((P + 1) × Q) groups communicate. For example, when P is 1.5, Q is 2, and 3 channels are used in 5 groups. In this case, the channel usage efficiency is the best.

  Second, R is calculated such that (P + R) is an integer (preferably the minimum), (P + R) channels are used, and (P + R + 1) groups communicate. For example, when P is 2.9, R is 0.1 and 3 channels are used in 4 groups. In this case, the R time is a no-signal period. The channel usage efficiency is not 100%, but an efficient system can be built with a small number of channels and groups.

  FIG. 10 is a diagram illustrating an operation of the communication group 1 to the communication group 4 in the present embodiment when viewed from each communication group, and is similar to the operation illustrated in FIG. The channel switching period (rest period) is indicated by hatching.

  Next, the operation of the present embodiment configured as described above will be described. The operation of the control unit 12a in this embodiment is the same as the flowchart in FIG. 8 described in the first embodiment. However, since the number of channels is 3, n = 3 in step S109. Each of the plurality of control means controls the start of the communication period so that the communication group 1, the communication group 2, the communication group 3, and the communication group 4 are shifted in order of T seconds.

  As described above, according to the wireless communication system according to the mode of the second embodiment of the present invention, in addition to the effects of the first embodiment, different communication groups shift communication periods from one another and each channel is always used by one of the communication groups. As described above, since the communication period is controlled, there is no signalless period when viewed from the channel side, and a limited channel can be used efficiently.

  FIG. 11 is a diagram illustrating the configuration of the wireless communication apparatus according to the third embodiment of the present invention. The difference from the configuration of the communication device 10a according to the first embodiment is that the control unit 12b of the communication device 10b according to the present embodiment includes a time calculation unit 14. The communication device 10b is provided in the communication group 1. Further, in the present embodiment, there are four communication groups, and a plurality of wireless communication devices having the same configuration as the communication device 10b are provided in each of the communication groups.

  The time calculation unit 14 calculates the remaining time from the current time to the end of the predetermined communication period based on the time information measured by the timer 15 in the predetermined communication period.

  The controller 12b does not transmit a frame whose transmission time is longer than the remaining time calculated by the time calculator 14, and transmits the frame in the next communication period. This is because if the control unit 12b transmits the long frame, the communication period ends in the middle of the frame, and the frame cannot be transmitted. Accordingly, the communication frequency decreases as the end of the communication period approaches.

  FIG. 12 is a diagram illustrating an operation of the communication control of each communication group as seen from the channel when the wireless communication system according to the present embodiment has four communication groups and the number of channels is three. Here, the memory 16 includes communication period information for which the communication period is 3.5 T seconds, channel switching period information for which the channel switching period is 0.5 T seconds, and pattern information that the three channels are repeatedly used in order. Remember. The same applies to memories of other communication devices in the communication group 1 and memories of communication devices in other communication groups.

  In FIG. 12, there is no non-signal period (rest period). As shown in FIG. 12, by shifting the communication period of each communication group by T seconds, four communication groups can communicate with each other using three channels.

  In each of the plurality of control means, the communication frequency of the first communication group decreases in two different communication groups, the first communication group whose communication frequency decreases near the end of the communication period and the second communication group whose communication period starts. The communication period is controlled so that communication is performed using the same channel at the time.

  For example, the communication period of the communication group 1 is 3.5 T seconds. In FIG. 12, communication can be performed using the channel 1 from time 0T to time 3.5T. However, since the control unit 12b does not transmit a frame whose transmission time is longer than the remaining time calculated by the time calculation unit 14, and transmits the frame in the next communication period, as the end of the communication period approaches, the communication frequency Go down. In FIG. 12, communication frequency of communication group 1 starts to decrease from time 2.5T, and communication is hardly performed at time 3.5T. Therefore, the communication group 4 starts communication on the channel 1 from the time 3T when the communication frequency of the communication group 1 is lowered to some extent.

  FIG. 13 is a diagram illustrating an operation of the communication group 1 to the communication group 4 in the present embodiment when viewed from each communication group, and is similar to the operation illustrated in FIG. The channel switching period (rest period) is indicated by hatching.

  Next, the operation of the present embodiment configured as described above will be described. FIG. 14 is a flowchart illustrating communication control of the control unit 12b in the wireless communication apparatus and wireless communication system according to the present embodiment. The difference from the flowchart of FIG. 8 described in the first embodiment is that the control unit 12b determines whether the frame transmission time is longer than the remaining time calculated by the time calculation unit 14 before performing communication in step S103. This is a point to judge (step S102). When the remaining time calculated by the time calculation unit 14 is longer than the frame transmission time, the control unit 12b performs communication by transmitting a frame (step S103). If the remaining time calculated by the time calculation unit 14 is shorter than the frame transmission time, the frame is not transmitted, and the process proceeds to the determination of whether or not the communication period of step S105 has elapsed. In addition, the frame that has not been transmitted is stored in, for example, the memory 16 and transmitted in the next communication period. The subsequent operation is the same as the flowchart of FIG.

  FIG. 15 is a diagram for explaining two types of MAC (Media Access Control) layer systems. In a network in which a large number of terminals share a single signal line, it is necessary to avoid a “collision” in which a plurality of terminals transmit data simultaneously. MAC is a transmission control technique used in a LAN or the like, and performs control to avoid the “collision” as described above.

  The CSMA method is a distributed access control method for the MAC layer of the LAN. In this method, each device on the LAN detects the presence or absence of a carrier on the channel, and transmits a frame when there is no carrier. However, when a frame is transmitted without detecting a carrier due to a transmission delay or the like, a frame collision occurs.

  The token passing method is one of LAN access control methods, in which “transmission right” data called a token always circulates in a network, and a terminal that captures the data transmits the data.

  Regardless of the communication means of the MAC layer, the control unit 12b determines whether or not the frame transmission time is longer than the remaining time calculated by the time calculation unit 14, and performs the above-described operation.

  FIG. 16 shows a general frame structure. PA refers to a preamble and is a pattern for obtaining bit synchronization of a frame. SD indicates a start delimiter and is a pattern for synchronizing the bytes of the frame. FC indicates frame control and indicates the type of frame. FCS refers to a frame check sequence and is data for checking the normality of data. ED indicates an end delimiter and is a pattern indicating the end of a frame.

  As described above, according to the wireless communication device and the wireless communication system according to the third embodiment of the present invention, in addition to the effects of the first and second embodiments, the control unit 12b is calculated by the time calculation unit 14. Frames whose transmission time is longer than the remaining time are not transmitted, and frames are transmitted in the next communication period, so unnecessary frame transmission is not performed. In addition, each of the plurality of control means has a communication frequency of the first communication group including two different communication groups, a first communication group in which the communication period is approaching and the communication frequency decreases and a second communication group in which the communication period starts. Since communication is performed using the same channel (the communication period is overlapped) at the time of lowering, the limited channel can be used efficiently.

  FIG. 17 is a diagram illustrating the configuration of the wireless communication apparatus according to the fourth embodiment of the present invention. The difference from the configuration of the third embodiment is that the control unit 12c of the communication device 10c in the present embodiment includes a synchronization data generation unit 21. Further, the communication device 10 c is provided in the communication group 1. Furthermore, in the present embodiment, there are two communication groups, and a plurality of wireless communication devices having the same configuration as the communication device 10c are provided in each of the communication groups.

  The synchronization data generation unit 21 generates synchronization data for synchronizing a predetermined communication period and a predetermined channel switching period with another wireless communication apparatus having the same configuration as the communication apparatus 10c. In this embodiment, the synchronization data generation unit 21 generates synchronization data based on the remaining time calculated by the time calculation unit 14. Further, the synchronization data has a valid value based on the elapsed time from the time of power-on of the self counted by the timer 15 and a group number for identifying the communication group to which the self belongs.

  The effective value is a numerical value indicating to which communication device the other communication device synchronizes when synchronizing, and synchronizes with the communication device having the largest effective value. In this embodiment, the elapsed time from when the power is turned on is used as an effective value. That is, the other communication device synchronizes with the communication device that has been operating for the longest time. When a communication device that has been newly turned on transmits a frame, if the synchronization of other communication devices that have been synchronized for a long time is found in the newly turned on device at the same time, This is because resynchronization occurs every time it is inserted and the system becomes unstable.

  As another example of the effective value, the number of devices having a remaining time close to that of the own device (counting from frames from devices received through radio) can be used.

  In this embodiment, the remaining time is used as the synchronization data, but it can be omitted in the case of a frame transmitted at a fixed timing such as the beginning of the communication period. Also, a synchronization timer not shown as another value can be used. The synchronization timer measures, for example, the elapsed time from the start of the communication period on channel 1 and is reset when the communication period on channel 1 starts again. From this synchronization timer, it is possible to determine which channel is used for the communication period or the channel switching period, or to calculate the remaining time of the communication period.

  In addition, when a plurality of communication groups use the same channel at different times, a group number is entered in the synchronization data. The communication apparatus that has received this frame calculates the synchronization timer value of the communication group to which the own apparatus belongs from the group number. In this way, a plurality of communication devices included in each of a plurality of communication groups can be easily synchronized.

  The control unit 12c adds the synchronization data generated by the synchronization data generation unit 21 in the frame to be transmitted.

  FIG. 18 is a diagram illustrating the remaining time used for the synchronization data generated by the synchronization data generation unit 21 in the communication device 10c in the present embodiment. A hatched line indicates a frame transmitted by the communication device 10c in the communication group 1. The frame transmitted during the communication period is added with the remaining time indicating the time from the end of the frame (possible at any position in the frame) to the end of the communication period.

  The remaining time 1 is added as synchronization data to the frame transmitted at the beginning of the channel 1 communication period. The frame 2 transmitted in the channel 1 communication period has the remaining time 2 added as synchronization data. Further, the remaining time 3 is added as synchronization data to the frame transmitted during the channel 2 communication period.

  FIG. 19 is a diagram illustrating a synchronization maintaining method using synchronization data. Each of the control means included in the device 2 and the device 3 that has received the frame first compares the effective value in the frame with the effective value of the own device. Judge that the operating time is long, and do not re-synchronize the frame. In the example of FIG. 19, each of the control means included in the device 2 and the device 3 determines that the effective value of the own device is small and that the own device is a newcomer, and determines the own device from the remaining time added to the frame. Modify the synchronization timer.

  Here, the control means included in the device 2 has started the communication period earlier than the device 1, but by referring to the synchronization data added to the frame transmitted from the device 1, the communication means extends the communication period. Synchronized with 1. The control means included in the device 3 has a communication period starting later than that of the device 1, but the communication period is shortened by referring to the synchronization data added to the frame transmitted from the device 1. Synchronized with. In this way, the devices 2 and 3 can synchronize with the device 1 and can synchronize all the devices.

  Here, a case is considered where subgroups that are 180 degrees out of phase are formed in the same communication group. FIG. 20 is a diagram illustrating an operation of the communication control of each subgroup when there are two subgroups in the communication group 1 as seen from the subgroup. Since the subgroup J and the subgroup K are in the same communication group, the user desires to communicate with each other.

  Since the subgroup J and the subgroup K are the same communication group, they have the same communication period information and channel switching period information. Therefore, although the two subgroups communicate with each other by alternately using two channels every 5 seconds as a whole, they are 180 degrees out of phase with each other. There is no opportunity to communicate using the same channel indefinitely, and the subgroup cannot be eliminated. If there is an opportunity to perform communication using the same channel, both subgroups can synchronize by transmitting frames to which the above-mentioned synchronization data is added.

  FIG. 21 is a diagram illustrating an operation of the communication group 1 and the communication group 2 in the wireless communication system according to the present embodiment when viewed from each communication group. In the present embodiment, each of the control means of the plurality of wireless communication devices in the same communication group controls the communication so that the communication period and the channel switching period are alternately repeated at the same timing, and sets the length of the communication period. Change for each channel.

  In FIG. 21, communication group 1 has a long communication period using channel 1 and a short communication period using channel 2. Conversely, communication group 2 has a short communication period using channel 1 and a long communication period using channel 2. However, in any case, the communication period is sufficiently longer than the channel switching period.

  Thus, by changing the length of the communication period for each channel, it is possible to solve the problem in the case where subgroups that are 180 degrees out of phase are formed in the same communication group as described in FIG. The reason is shown in FIG.

FIG. 22 is a diagram illustrating an operation of the communication control of the subgroup J and the subgroup K in the wireless communication system according to the present embodiment when viewed from the subgroup. Since the two subgroups both belong to the communication group 1, the communication period using the channel 1 is long and the communication period using the channel 2 is short as described with reference to FIG. Therefore, even if the phases are shifted from each other by 180 degrees, there can be an overlapping period (a period indicated by a diamond in FIG. 22) in which communication can be performed between the subgroups. Each of the plurality of control means can eliminate synchronization by synchronizing and transmitting the frame with the synchronization data added during this overlap period. Next, the present embodiment configured as described above can be used. The operation of the form will be described. The operations of the wireless communication apparatus and the wireless communication system in the present embodiment are the same as the operations of the first embodiment described with reference to FIG. However, when performing communication in step S103, the control unit 12c adds the synchronization data generated by the synchronization data generation unit 21 to the frame to be transmitted and synchronizes.

  Further, when determining whether or not the predetermined communication period has elapsed in step S105, the control unit 12c refers to a communication period that differs for each channel. Therefore, the memory 16 stores different communication period information for each channel. The subsequent operation is the same as the flowchart of FIG.

  As described above, according to the wireless communication apparatus according to the fourth embodiment of the present invention, the control unit 12c includes the synchronization data generation unit 21 and transmits the synchronization data generated by the synchronization data generation unit 21. Therefore, it is possible to synchronize with other wireless communication devices in the same communication group, and broadcast communication can be facilitated.

  Further, since the synchronization data is generated based on the remaining time calculated by the time calculation unit 14, it is possible to correctly synchronize the timings of the communication periods of a plurality of communication devices in the same communication group.

  Further, since the synchronization data has an effective value based on the elapsed time from the time of power-on of the own time counted by the timer 15 and a group number for identifying the communication group to which the self belongs, the communication device that has been operating for the longest time Other communication devices can synchronize with each other to form a stable system, and even when there are a plurality of communication groups, synchronization can be performed correctly.

  Furthermore, according to the wireless communication system according to the fourth embodiment of the present invention, each of the control means of the plurality of wireless communication devices in the same communication group alternately repeats the communication period and the channel switching period at the same timing. As described above, the communication is controlled and the length of the communication period is changed for each channel. Therefore, even when there are wireless communication apparatuses that are not synchronized in the same communication group, synchronization can be efficiently achieved.

  When the wireless communication system according to the fourth embodiment is used, if a channel having a long communication period cannot be used due to a collision or the like, the deviation may not be eliminated. For example, in FIG. 22, when channel 1 cannot be used due to a collision, an overlap period does not occur, so that the problem arises that the two subgroups cannot synchronize with each other. Example 5 can be considered as a method for solving this problem.

  FIG. 23 is a block diagram illustrating a configuration of the wireless communication apparatus according to the fifth embodiment of the present invention. The difference from the configuration of the fourth embodiment is that the control unit 12d of the communication device 10d in the present embodiment includes a random number generation unit 24. The communication device 10d is provided in the communication group 1. Further, in this embodiment, there are two communication groups, and a plurality of wireless communication devices having the same configuration as the communication device 10d are provided in each of the communication groups.

  The random number generator 24 generates a common random number within the same communication group.

  The controller 12d determines the length of the communication period based on the common random number generated by the random number generator 24.

  FIG. 24 is a diagram illustrating a communication period determined by the random number generation unit 24 included in the communication device 10d in the communication group 1 based on a pseudo noise (M-sequence random number, etc.) signal. FIG. 25 is a diagram illustrating an operation of the communication control of the subgroup D and the subgroup E in the communication group 1 when viewed from the subgroup. Overlap periods are indicated by diamonds.

  It is known that pseudo noise has high autocorrelation and low cross correlation. Therefore, even if a communication period shift occurs between the subgroups as shown in FIG. 25, the cross-correlation between the subgroups is low, and a time zone in which the same channel is always used occurs. Therefore, even if a collision occurs in a plurality of channels and those channels are disconnected, if there is at least one normal channel, a frame with synchronization data added is transmitted to eliminate the deviation. Can do.

  As described above, each of the plurality of control means in the same communication group can eliminate the communication period shift that occurs between the subgroups.

  FIG. 26 is a diagram illustrating an example of communication control of the communication group 1 and the communication group 2 of the wireless communication system according to the present embodiment when viewed from each communication group. In the present embodiment, each of the control means of the plurality of wireless communication devices in the same communication group controls the communication so that the communication period and the channel switching period are alternately repeated at the same timing, and is generated by the random number generator 24. The length of the communication period is determined based on the common random number.

  As shown in FIG. 26, as in the case of between subgroups, an overlapping period using the same channel as shown by a rhombus occurs. Therefore, by intercepting communication of other communication groups during this period, each of the plurality of control means can easily control the communication period so that different communication groups do not use the same channel at the same time. . However, the synchronization data must include group number information.

  Next, the operation of the present embodiment configured as described above will be described. The operations of the wireless communication apparatus and the wireless communication system in the present embodiment are the same as those in the fourth embodiment. However, when determining whether or not the predetermined communication period has elapsed in step S105 of FIG. 8, the control unit 12c determines the communication period based on the common random number generated by the random number generation unit 24. The subsequent operation is the same as the flowchart of FIG.

  As described above, according to the wireless communication device and the wireless communication system according to the fifth embodiment of the present invention, the length of the communication period is determined based on the common random number generated by the random number generator 24 hours. In addition to the effect of Example 4, even if a collision occurs in a plurality of channels and those channels are disconnected, if there is at least one normal channel, a frame with synchronization data added is transmitted, The deviation can be eliminated. Furthermore, when a communication period shift occurs between different communication groups, the communication period shift can be eliminated by transmitting frames in the overlapping use period of the same channel.

  FIG. 27 is a diagram illustrating transmission timing when the CSMA scheme is used for the MAC layer. When a frame transmission request is generated within the communication period, the frame is transmitted as it is. However, transmission requests generated at the end of the communication period and the channel switching period that cannot be completed within the communication period are transmitted simultaneously at the beginning of the next communication period. Therefore, normally, transmission requests are evenly distributed regardless of the timing of the communication period. However, the communication frequency increases every time at the beginning of the communication period, and in particular, in the CSMA scheme, the collision probability increases, and the delay and frame loss probability. The problem that becomes high arises. Example 6 shown below can be considered as a method for solving this problem.

  FIG. 28 is a block diagram illustrating a configuration of a wireless communication apparatus according to Embodiment 6 of the present invention. The difference from the configuration of the third embodiment is that the control unit 12e of the communication device 10e in the present embodiment includes a delay time calculation unit 22. The communication device 10e is provided in the communication group 1. Furthermore, in the present embodiment, there is one communication group, and a plurality of wireless communication devices having the same configuration as the communication device 10e are provided.

  Based on the time information measured by the timer 15, the delay time calculation unit 22 calculates the time for delaying the frame transmission time corresponding to the timing of the predetermined communication period and the predetermined channel switching period. In the present embodiment, the time calculation unit 14 is not essential, but for example, the delay time calculation unit 22 may calculate the time for delaying the frame transmission time based on the remaining time calculated by the time calculation unit 14. Is possible.

  The control unit 12e delays the frame transmission time based on the time calculated by the delay time calculation unit 22.

FIG. 29 is a diagram illustrating transmission timing when the wireless communication apparatus according to the present embodiment is used. The actual transmission time is delayed according to the delay time function with respect to the transmission request time. The delay time calculation unit 22 has this delay time function inside, and calculates a delay time corresponding to the cycle time position of the communication period and the channel switching period. The control unit 12e delays the frame requested to be transmitted by the delay time and transmits the frame through the transmission unit 18. In the example of FIG. 29, the delay time function is a uniform attenuation function. At time t ₀ 1 frame is the end of the communication period can not be sent, the delay time is the minimum to the maximum. Thereafter, the delay time in accordance undergo time t ₁ and time t ₂ which is the end of inter-channel switching period which is the beginning of the inter-channel switching period is gradually attenuated, again a delay time at time t ₃ which is the end of the next communication period Is from minimum to maximum.

  Next, the operation of the present embodiment configured as described above will be described. The operation of the wireless communication apparatus in the present embodiment is the same as that of the first embodiment. However, when performing communication in step S103 of FIG. 8, the control unit 12e delays the transmission time of the frame based on the time calculated by the delay time calculation unit 22. The subsequent operation is the same as the flowchart of FIG.

  As described above, according to the wireless communication apparatus according to the sixth embodiment of the present invention, as shown in FIG. 29, the delay time calculation unit 22 is provided so that the actual transmission time is uniform in the communication period. To be distributed. Therefore, the collision probability is greatly reduced, and the large delay and the frame disappearance probability are reduced.

  The present invention can be applied to a building air-conditioning wireless controller that performs control by a specific low-power radio or the like.

It is a block diagram which shows the structure of the radio | wireless communication apparatus and radio | wireless communications system of the form of Example 1 of this invention. It is a figure which shows the operation | movement which looked at the communication control of the communication group from the channel in the radio | wireless communications system of Example 1 of this invention. It is a figure which shows the operation | movement which looked at the communication control of the communication group in the radio | wireless communications system of Example 1 of this invention from the communication group. It is a figure which shows the operation | movement which looked at the communication control of the communication group 1 and the communication group 2 from the channel in the radio | wireless communications system of Example 1 of this invention. It is a figure which shows the operation | movement which looked at the communication control of the communication group 1 and the communication group 2 in the radio | wireless communications system of Example 1 of this invention from the communication group. It is a figure which shows the operation | movement which looked at the communication control of each communication group from the channel when the radio | wireless communications system of the form of Example 1 of this invention has N communication groups. It is a figure which shows the operation | movement which looked at the communication control of each communication group when the radio | wireless communications system of the form of Example 1 of this invention has N communication groups from the communication group. It is a flowchart figure which shows operation | movement of the control part of the radio | wireless communication apparatus of the form of Example 1 of this invention. It is a figure which shows the operation | movement which looked at communication control of each communication group from the channel when the radio | wireless communications system of the form of Example 2 of this invention has four communication groups, and the number of channels is three. It is a figure which shows the operation | movement which looked at the communication control of the communication group 1 thru | or the communication group 4 of the radio | wireless communications system of Example 2 of this invention from each communication group. It is a block diagram which shows the structure of the radio | wireless communication apparatus of the form of Example 3 of this invention. It is a figure which shows the operation | movement which looked at the communication control of each communication group from the channel when the radio | wireless communications system of Example 3 of this invention has four communication groups, and the number of channels is three. It is a figure which shows the operation | movement which looked at communication control of the communication group 1 thru | or the communication group 4 of the radio | wireless communications system of Example 3 of this invention from each communication group. It is a flowchart figure which shows operation | movement of the control part of the radio | wireless communication apparatus of the form of Example 3 of this invention. It is a figure explaining two types of MAC layer systems. It is a figure which shows a general frame structure. It is a block diagram which shows the structure of the radio | wireless communication apparatus of the form of Example 4 of this invention. It is a figure explaining the remaining time used for the synchronous data which the synchronous data generation part in the radio | wireless communication apparatus of the form of Example 4 of this invention produces | generates. It is a figure which shows the synchronization maintenance method by synchronous data in the radio | wireless communications system of the form of Example 4 of this invention. It is a figure which shows the operation | movement which looked at the communication control of each subgroup when the two subgroups exist in the communication group 1 from the subgroup. It is a figure which shows the operation | movement which looked at the communication control of the communication group 1 and the communication group 2 of the radio | wireless communications system of Example 4 of this invention from each communication group. It is a figure which shows the operation | movement which looked at the communication control of the subgroup J and the subgroup K of the radio | wireless communications system of Example 4 of this invention from the subgroup. It is a block diagram which shows the structure of the radio | wireless communication apparatus of the form of Example 5 of this invention. It is a figure which shows the communication period which the random number generation part which the radio | wireless communication apparatus of Example 5 of this invention has has determined based on the pseudo noise signal. It is a figure which shows the operation | movement which looked at the communication control of the subgroup D and the subgroup E in the communication group 1 of the radio | wireless communications system of Example 5 of this invention from the subgroup. It is a figure which shows the operation | movement which looked at one example of the communication control of the communication group 1 and the communication group 2 of the radio | wireless communications system of Example 5 of this invention from each communication group. It is a figure which shows the transmission timing at the time of using a CSMA system for a MAC layer. It is a block diagram which shows the structure of the radio | wireless communication apparatus of the form of Example 6 of this invention. It is a figure which shows the transmission timing at the time of using the radio | wireless communication apparatus of the form of Example 6 of this invention.

Explanation of symbols

1, 2 Communication groups 10a, 10b, 10c, 10d Communication devices 12a, 12b, 12c, 12d Control unit 13 Channel switching unit 14 Time calculation unit 15 Timer 16 Memory 17 Frequency generation unit 18 Transmission unit 19 Reception unit 20 Communication device 21 Synchronization Data generator 22 Delay time calculator 24 Random number generator 30, 40, 50, 60, 70, 80 Communication device

Claims (13)

A wireless communication device that performs wireless communication using a plurality of channels having different frequencies,
A timer to time,
Based on the time information timed by the timer, a predetermined communication period for transmitting and receiving one or more frames and switching from the currently used channel to the other channel among the plurality of channels Control means for controlling communication so as to alternately repeat a predetermined channel switching period,
The control means includes
A wireless communication apparatus comprising: a channel switching unit that switches from a currently used channel to another channel among the plurality of channels according to a predetermined pattern during the predetermined channel switching period.   Comprising storage means for storing communication period information for representing the predetermined communication period, channel switching period information for representing the predetermined channel switching period, and pattern information for representing the predetermined pattern. The wireless communication apparatus according to claim 1. The control means includes
Within the predetermined communication period, based on the time information timed by the timer, has a time calculation unit that calculates the remaining time from the current time to the end of the predetermined communication period, and is calculated by the time calculation unit 3. The wireless communication apparatus according to claim 1, wherein a frame having a transmission time longer than the remaining time is transmitted in the next communication period. The control means includes
Based on the time information timed by the timer, having a delay time calculation unit for calculating a time to delay the time to transmit a frame corresponding to the timing of the predetermined communication period and the predetermined channel switching period, The radio communication apparatus according to claim 1, wherein the frame transmission time is delayed based on the time calculated by the delay time calculation unit. The control means includes
A synchronization data generating unit that generates synchronization data for synchronizing the predetermined communication period and the predetermined channel switching period between the wireless communication apparatus and another wireless communication apparatus having the same configuration; The wireless communication apparatus according to any one of claims 1 to 4, wherein the synchronization data generated by the data generation unit is added to a frame to be transmitted. The control means includes
Synchronization data for synchronizing the predetermined communication period and the predetermined channel switching period with another wireless communication apparatus having the same configuration as the wireless communication apparatus based on the remaining time calculated by the time calculation unit 5. The wireless communication apparatus according to claim 3, further comprising a synchronization data generation unit that generates the synchronization data generated by the synchronization data generation unit in a frame to be transmitted.   The synchronization data generated by the synchronization data generation unit includes at least one of a valid value based on an elapsed time from power-on of the self measured by the timer and a group number for identifying a communication group to which the synchronization data belongs. The wireless communication apparatus according to claim 5, further comprising: A wireless communication system comprising a plurality of wireless communication devices according to any one of claims 1 to 7, and comprising one or more communication groups in which the plurality of wireless communication devices communicate with each other.
Each of the control means of the plurality of wireless communication devices in the same communication group controls communication so as to alternately repeat the communication period and the channel switching period at the same timing,
Each of the channel switching units of the plurality of wireless communication devices in the same communication group changes from the currently used channel of the plurality of channels to another channel according to the same pattern during the predetermined channel switching period. A wireless communication system characterized by switching.   9. The wireless communication system according to claim 8, wherein each of the plurality of control means controls a communication period so as not to perform communication using the same channel at the same time as a different communication group.   10. Each of the plurality of control means controls communication periods so that different communication groups shift communication periods from each other and each channel is always used by any communication group. Wireless communication system. A wireless communication system comprising a plurality of wireless communication devices according to claim 3, claim 4 or claim 6, and comprising one or more communication groups with which the plurality of wireless communication devices communicate with each other.
In each of the plurality of control means, the communication frequency of the first communication group decreases in two different communication groups, the first communication group whose communication frequency decreases near the end of the communication period and the second communication group whose communication period starts. A wireless communication system, wherein a communication period is controlled so as to perform communication using the same channel at a time. A wireless communication system comprising a plurality of wireless communication devices according to any one of claims 5 to 7, and comprising one or more communication groups in which the plurality of wireless communication devices communicate with each other.
Each of the control means of the plurality of wireless communication devices in the same communication group controls communication so that the communication period and the channel switching period are alternately repeated at the same timing, and sets the length of the communication period. A wireless communication system characterized by changing for each channel.   Each of the control means of the plurality of wireless communication devices in the same communication group has a random number generator that generates a common random number in the same communication group, and based on the common random number generated by the random number generator The wireless communication system according to claim 12, wherein the length of the communication period is determined.

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