JP2007005859A - Radio communication system, radio communication apparatus and beacon cycle management method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an avoiding measure suitable for an autonomous dispersion system against beacon collision between different radio networks. <P>SOLUTION: A beacon cycle detector 120 extracts beacons from signals demodulated and decoded in a receiver 110, and detects a beacon cycle for each of radio communication apparatuses transmitting the beacons. An error rate measuring section 130 extracts the beacons and data from the signals demodulated and decoded in the receiver 110, and measures an error rate of each of them. A beacon cycle management 140 corrects its beacon cycle so that it becomes longer, if the error rate of the beacon measured in the section 130 is higher than the error rate of the data. After that, when the error rate of the beacon becomes higher than the error rate of the data, the management 140 brings its beacon cycle into an original state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication system in which a plurality of wireless communication devices are autonomously distributed to form a network, and in particular, a wireless communication device that corrects a beacon period according to propagation loss, a wireless communication system, and a processing method therefor and The present invention relates to a program for causing a computer to execute a method.

  As a wireless network control method in a wireless communication system, only a control station (controller) called an access point transmits a beacon to control the entire network, and each wireless communication device transmits a beacon in a distributed manner. Therefore, there is an autonomous distributed system that configures a network. In IEEE 802.11, which is a wireless local area network (LAN) standard, the former belongs to the infrastructure mode (Infrastructure Mode; Infrastructure Basic Service Set mode), and the latter belongs to the ad hoc mode (ad hoc mode). ; Independent Basic Service Set mode).

  The centralized control method has an advantage that network maintenance is relatively easy because network control is unified. Here, maintaining the network means optimal allocation of radio resources, frequency channel switching, beacon transmission timing, interval, and the like.

  On the other hand, since the autonomous distributed system does not require an access point, there is an advantage that a network can be formed ad hoc as needed. For example, it is suitable when a network is configured by a plurality of mobile devices.

  However, while an autonomous distributed wireless network has the advantage of being able to form an ad hoc network, maintaining the network is not always easy. The reason for this is that, in the centralized control method, the access point only needs to give instructions to each wireless communication device unilaterally, but in the autonomous distributed method, negotiation and transmission of instructions are required between the wireless communication devices. It is to become.

  As a case where control for maintaining the network is necessary, consider a situation where a plurality of wireless networks exist adjacent to each other. In such a situation, a wireless communication device existing in the vicinity of the intersection of two networks receives a transmission signal from a wireless communication device belonging to each network. A problem in such a situation is when the transmission timings of beacon signals necessary for network maintenance overlap between adjacent networks. This is because beacons are transmitted at regular intervals, unlike normal data transmission.

  Such a beacon collision problem can be improved by shifting the beacon timing for a certain period of time, but some information transmission is required for this purpose. In an autonomous decentralized wireless network, the beacon transmission timing determined at the time of network formation is shared by a plurality of wireless communication devices, so the message “shift transmission timing from a certain frame” is transmitted to all those wireless communication devices. There is a need to. In particular, when some wireless communication devices are intermittently operated due to low power consumption, it is difficult to ensure that a transmission timing change message arrives by a designated frame.

Therefore, conventionally, a technique for avoiding beacon collision and preventing interference between wireless networks by transmitting beacons at time intervals having jitter is known (see, for example, Patent Document 1).
Special Table 2000-517132 (FIG. 4)

  In the above-described prior art, beacons are transmitted at time intervals having jitter, but the average period between beacons is still a fixed period, and the possibility that a collision occurs between beacons still remains. In addition, it is necessary to share information regarding jitter between wireless communication apparatuses, and there is a problem in that it is inefficient to implement in an autonomous distributed network.

  Accordingly, an object of the present invention is to provide a workaround suitable for an autonomous distributed system against beacon collision between different wireless networks.

  The present invention has been made to solve the above problems, and a first aspect thereof is a wireless communication system in which a plurality of wireless communication devices are autonomously distributed to form a network, and the plurality of wireless communication devices Each of the devices adjusts the beacon period to a beacon period detecting unit that detects a beacon period from beacon signals received from the plurality of wireless communication apparatuses and a wireless communication apparatus in which the detected beacon period is most shifted in a predetermined direction. A beacon period managing means for managing its own beacon period; a propagation loss measuring means for measuring beacon and data propagation loss from a predetermined wireless communication apparatus among the plurality of wireless communication apparatuses; and the own beacon period. Beacon generating means for generating a beacon based on the beacon period managing means, There is a wireless communication system, characterized in that the beacon period of the own until the condition is resolved in the more states than the propagation loss of the data continues to shift to the predetermined direction. As a result, in a state where beacons collide with different wireless networks and the propagation loss of beacons is larger than the propagation loss of data, the state is resolved by continuously shifting the beacon period of the wireless communication device in a predetermined direction. This brings about the effect.

  Here, the predetermined direction means either the slow direction or the fast direction on the time axis. That is, if it is assumed that the beacon cycle management means manages its own beacon cycle so that the beacon cycle is matched with the wireless communication apparatus having the slowest beacon cycle, this predetermined direction means a slow direction on the time axis. Further, if it is assumed that the beacon period management means manages its own beacon period so as to match the beacon period to the wireless communication device with the earliest beacon period, this predetermined direction means a fast direction on the time axis.

  According to a second aspect of the present invention, there is provided a wireless communication apparatus in a wireless communication system in which a plurality of wireless communication apparatuses are autonomously distributed to form a network, wherein a beacon period is determined from beacon signals received from the plurality of wireless communication apparatuses. A beacon period detecting means for detecting the beacon period, a beacon period managing means for managing the beacon period so that the detected beacon period is aligned with a wireless communication apparatus having the most shifted beacon in a predetermined direction, and the plurality of wireless communication apparatuses A beacon and data propagation loss from a predetermined wireless communication apparatus, and a beacon generation means for generating a beacon based on the beacon period of the device, the beacon period management The means is that in a state where the propagation loss of the beacon is greater than the propagation loss of the data, the state is A beacon period of the own until extinguished is a wireless communication device characterized by continuing shifted in the predetermined direction. By this, a beacon collides with another wireless communication device belonging to a different wireless network, and in a state where the propagation loss of the beacon is larger than the propagation loss of the data, the own beacon period is continuously shifted in a predetermined direction. It brings about the effect of eliminating the state.

  According to a third aspect of the present invention, there is provided a wireless communication apparatus in a wireless communication system in which a plurality of wireless communication apparatuses are autonomously distributed to form a network, wherein a beacon period is determined from beacon signals received from the plurality of wireless communication apparatuses. A beacon period detecting means for detecting the beacon period, a beacon period managing means for managing the beacon period so that the detected beacon period is aligned with a wireless communication apparatus having the most shifted beacon in a predetermined direction, and the plurality of wireless communication apparatuses A beacon and data propagation loss from a predetermined wireless communication apparatus, and a beacon generation means for generating a beacon based on the beacon period of the device, the beacon period management The means receives beacons from other wireless communication devices that form networks other than the above network. When the beacon cycle of the beacon is shifted in the predetermined direction from the beacon cycle of the beacon, the propagation loss of the beacon measured by the propagation loss measuring means is larger than the propagation loss of the data. When the state is canceled, the wireless communication apparatus corrects the own beacon period to match the beacon period of the beacon from the other wireless communication apparatus. Thus, in a state where a beacon collides with another wireless communication device belonging to a different wireless network and the propagation loss of the beacon is larger than the propagation loss of data, the beacon period from the other network is the own beacon period. In the case where the position is displaced in the predetermined direction, the operation of waiting for the state to be canceled is brought about.

  In the third aspect, the beacon period managing means may detect that the beacon period from the other wireless communication apparatus is not searched or the beacon period of the searched beacon is shifted in the predetermined direction from the own beacon period. If the beacon propagation loss is larger than the data propagation loss, the beacon period of the own beacon can be continuously shifted in the predetermined direction until the state is eliminated. Thereby, even in a situation where a state where the propagation loss of the beacon is larger than the propagation loss of the data is not naturally improved, the state is canceled by continuously shifting its own beacon period in a predetermined direction.

  In addition, the fourth aspect of the present invention is that, among a plurality of wireless communication devices that autonomously distribute and form a network, the beacon cycle is adjusted so that the beacon cycle is aligned with a wireless communication device whose beacon cycle is most shifted in a predetermined direction. A wireless communication device that manages a beacon and data propagation loss from a predetermined wireless communication device among the plurality of wireless communication devices, and the beacon propagation loss is greater than the data propagation loss. A procedure for correcting the beacon period in a predetermined direction when there are many, and a procedure for returning the beacon period to the pre-correction when the beacon is lost from the state in which the propagation loss of the beacon is greater than the propagation loss of the data. A program for causing a computer to execute a beacon cycle management method or a procedure thereof. By this, a beacon collides with another wireless communication device belonging to a different wireless network, and in a state where the propagation loss of the beacon is larger than the propagation loss of the data, the own beacon period is continuously shifted in a predetermined direction. It brings about the effect of eliminating the state.

  According to the present invention, an excellent effect of avoiding beacon collision between different wireless networks by the autonomous distributed method can be achieved.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a state in which different wireless networks are adjacent to each other in the wireless communication system according to the embodiment of the present invention. Here, the wireless communication apparatuses 11, 12, 13 and 14 form a wireless network #A (10) based on the autonomous distributed system, and the wireless communication apparatuses 21, 22, and 23 configure a wireless network #B (20) based on the autonomous distributed system. It shall be formed.

  The wireless communication device 14 is a terminal that forms the wireless network #A (10). On the other hand, it is assumed that the wireless communication device 14 is in a position where radio waves from the wireless network #B (20) can be received. At this time, if the beacon timing of the wireless network #A (10) and the beacon timing of the wireless network #B (20) overlap, a beacon collision occurs at the position of the wireless communication device 14.

  FIG. 2 is a diagram showing a relationship between beacons by different wireless networks in the embodiment of the present invention. In the wireless network #A (10), it is assumed that a beacon period 611 and a data communication period 612 are provided in the superframe period 610. Each of the wireless communication devices forming the wireless network #A (10) transmits its beacon in the beacon period 611 and receives beacons from other wireless communication devices. Thereby, the mutual wireless communication devices forming the wireless network are recognized, and synchronization of the beacon period (that is, synchronization of the superframe period 610) is performed. Each of the wireless communication devices transmits its own data in the data communication period 612 and receives data from other wireless communication devices. That is, in this data communication period 612, data communication is performed with another wireless communication device. In the wireless network #A (10), the beacon period 611 and the data communication period 612 are repeated every superframe period 610.

  Although the beacon period 611 and the data communication period 612 in the wireless network #A (10) have been described here, the same applies to the beacon period 621 and the data communication period 622 in the wireless network #B (20).

  Referring to FIG. 2A, there is an overlapping period between the beacon period 611 of the wireless network #A (10) and the beacon period 621 of #B (20). That is, in the period in which these overlap, the radio communication device 14 of FIG. 1 receives both the beacon in the radio network #A (10) and the beacon in the radio network #B (20), so that the beacons collide with each other. It is considered that the probability of causing a reception error due to the error increases.

  If the period of the superframe period 610 in the wireless network #A (10) is shifted for some reason from the state of FIG. 2 (a) and becomes as shown in FIG. 2 (b), the beacon period of the wireless network #A (10) There is no overlapping period between 611 and the beacon period 621 of #B (20). Therefore, in this state, the beacon does not collide even in the wireless communication device 14 of FIG.

  In the embodiment of the present invention, the beacon period is set so as to maintain the state of FIG. 2B by forcibly shifting from the state of FIG. 2A described here to the state of FIG. 2B. Control. For this purpose, the following configuration is provided.

  FIG. 3 is a diagram illustrating a configuration example of the wireless communication device 100 according to the embodiment of the present invention. The wireless communication apparatus 100 includes an antenna 101, a switch 102, a receiving unit 110, a beacon period detecting unit 120, an error rate measuring unit 130, a beacon period managing unit 140, a timer 150, and a beacon period table 160. And a beacon generator 180 and a transmitter 190.

  The antenna 101 is an antenna for transmitting and receiving wireless radio waves to and from other wireless communication devices. The switch 102 is a switch for switching to connect the antenna 101 to either the reception unit 110 or the transmission unit 190. The receiving unit 110 converts a high frequency signal received by the antenna 101 into an intermediate signal, and performs demodulation and decoding.

  The beacon period detection unit 120 extracts a beacon from the signal demodulated and decoded by the reception unit 110 and detects a beacon period for each wireless communication device that has transmitted the beacon. In particular, in the case of the same wireless standards, the beacon period can be specified by recognizing the other party's beacon.

  The error rate measuring unit 130 extracts a beacon and data from the signal demodulated and decoded by the receiving unit 110, and measures each error rate. This error rate can be obtained from the detection rate by detecting an error by checking the error detection code of the frame body held in the FCS (Frame Check Sequence) field in the MAC frame, for example.

  The beacon period management unit 140 manages the beacon period of the wireless communication device 100. This beacon period management unit 140 manages its own beacon period so that the beacon period is matched to the wireless communication apparatus with the slowest beacon period among the wireless communication apparatuses that form a wireless network based on the autonomous decentralization method as a premise function. To do. When the beacon period is adjusted to the wireless communication device with the slowest beacon period, the beacon period of the slowest wireless communication apparatus is continuously monitored. If the beacon period changes for any reason, the beacon period after the change is further followed. Control is performed.

  For example, it is assumed that when a certain wireless communication device X counts 1 million clocks in its own reference clock, it becomes one beacon period. It is assumed that when this wireless communication device X measures the beacon period of another wireless communication device Y in the same network, it is (1 million + 5) clocks. At this time, the reference clock of the wireless communication device Y is delayed with respect to the wireless communication device X. Therefore, other wireless communication devices including the wireless communication device X set their beacon cycle to (1 million + 5) clocks and continuously monitor the beacon cycle of each wireless communication device in the same network. Here, it is assumed that the beacon period of the wireless communication apparatus Y varies from (1 million + 5) clock to (1 million + 2) clock for some reason. In this case, other wireless communication devices including the wireless communication device X tentatively correct the beacon period to (1 million + 2) clocks. Each wireless communication device again monitors the beacon period of the surrounding wireless communication devices after a certain period of time to find out which beacon has the longest cycle. The same operation is performed when the beacon disappears due to the power of the wireless communication device Y being turned off. Thus, control is performed so that unnecessary correction does not continue indefinitely.

  In addition, although the example which matches a beacon period with the wireless communication apparatus with the slowest beacon period was demonstrated here, you may comprise this so that a beacon period may be matched with the wireless communication apparatus with the earliest beacon period. That is, it is assumed as a premise of the function of the beacon period management unit 140 that the beacon period is managed so as to match the beacon period to the wireless communication device that is most shifted in a certain direction.

  Also, the beacon period management unit 140 controls its own beacon period in accordance with the error rate measured by the error rate measurement unit 130 as follows. That is, if the beacon error rate in the beacon period 611 is higher than the data error rate in the data communication period 612, the beacon period management unit 140 recognizes that the beacon period management unit 140 is in the state of FIG. Is adjusted to be longer. Thereafter, if the error rate of the beacon does not become higher than the error rate of the data, the beacon cycle management unit 140 recognizes that the state has transitioned to the state of FIG. 2B, and returns its beacon cycle to the state before correction. .

  However, if the beacon period from another wireless network causing a beacon collision can be specified by the beacon period detection unit 120, if the beacon period is later than its own beacon period, the system waits as it is and then waits as shown in FIG. ) State can be expected to transition to the state of FIG. Therefore, wait if the beacon error rate is higher than the data error rate, and if the beacon error rate is no longer higher than the data error rate, the beacon period of the other wireless network causing the beacon collision is the same. The beacon period management unit 140 corrects its own beacon period.

  The timer 150 is a timer that gives a time limit when the beacon period management unit 140 corrects the beacon period. If the beacon error rate does not improve after waiting for a long time, there may be another factor. Therefore, when waiting for improvement in the error rate of the beacon, the timer 150 measures the time, and when this times out, the process is terminated.

  The beacon cycle table 160 is a table for holding the beacon cycle of each wireless communication device that forms a wireless network with the wireless communication device 100. A specific configuration example will be described later.

  The beacon generation unit 180 generates a beacon of the wireless communication device 100 itself according to the beacon cycle of each wireless communication device held in the beacon cycle table 160. The beacon generated by the beacon generation unit 180 is transmitted by the transmission unit 190 to another wireless communication device via the antenna 101.

  FIG. 4 is a diagram illustrating a configuration example of the beacon period table 160 according to the embodiment of the present invention. The beacon period table 160 includes fields of a device identifier 161, a beacon period 162, and a beacon payload 163.

  The device identifier 161 is a field that holds an identifier for identifying each wireless communication device forming the wireless network. As such an identifier, for example, a MAC address or the like can be used. The beacon period 162 is a field that holds the beacon period of the corresponding wireless communication device. The beacon payload 163 is a field that holds the contents of the beacon of the corresponding wireless communication device.

  The beacon period management unit 140 stores and manages the beacon period detected by the beacon period detection unit 120 in the beacon period table 160 together with the contents of the beacon. Further, the beacon generation unit 180 generates a beacon at that timing based on the beacon period of the wireless communication device 100 held in the beacon period table 160.

  Next, the operation of the wireless communication apparatus according to the embodiment of the present invention will be described with reference to the drawings.

  FIG. 5 is a diagram illustrating an example of an operation procedure of the wireless communication device 100 according to the embodiment of the present invention. First, the error rate measurement unit 130 identifies a wireless communication device that is mainly communicating with itself in a wireless network, and transmits an error rate PERb of a beacon transmitted from the specific wireless communication device and the specific wireless communication. The error rate PERd of the data transmitted from the apparatus is measured (step S911). As a result, if the beacon error rate PERb is higher than the data error rate PERd, the following processing is performed; otherwise, the following processing is not performed (step S912).

  After the timer 150 is reset (step S921), the beacon period management unit 140 corrects its own beacon period TNWx to be longer (slower) (step S922). The beacon error rate PERb and the data error rate PERd are measured by the error rate measuring unit 130 (step S923) until the beacon error rate PERb is not higher than the data error rate PERd (until improved). Wait (step S924). During this time, when the timer 150 times out, the standby process ends (step S925). When the standby process ends in this way, the beacon period management unit 140 returns its own beacon period TNWx to the state before correction in step S922 (step S926).

  As described above, according to the procedure example of FIG. 5 in the embodiment of the present invention, the beacon error rate is reduced by delaying the own beacon period when the beacon error rate PERb is higher than the data error rate PERd. Can be improved and maintained in the improved state.

  FIG. 6 is a diagram illustrating another example of the operation procedure of the wireless communication device 100 according to the embodiment of the present invention. First, as in the example of FIG. 5, the error rate measurement unit 130 specifies a wireless communication device that is mainly communicating with itself in the wireless network, and the error of the beacon transmitted from the specific wireless communication device. The rate PERb and the error rate PERd of data transmitted from the specific wireless communication device are measured (step S931). As a result, if the beacon error rate PERb is higher than the data error rate PERd, the following processing is performed; otherwise, the following processing is not performed (step S932).

  The beacon period detection unit 120 identifies its own beacon period TNWx (step S933). The beacon period detection unit 120 searches for a beacon from a wireless communication device of another wireless network in which a beacon collision has occurred (step S934). As a result, if a beacon can be found (step S935), the beacon period detection unit 120 specifies the beacon period TNWy (step S936). If the other beacon period TNWy is longer than its own beacon period TNWx (step S937), the improvement standby process (step S950) is performed. If not, or if the beacon is not found in step S934, the forced adjustment process ( Step S940) is performed.

  FIG. 7 is a diagram showing an example of the forced adjustment process (step S940) of FIG. 6 in the embodiment of the present invention. Here, after the timer 150 is reset (step S941), the beacon period management unit 140 corrects its own beacon period TNWx to be longer (slower) (step S942).

  Then, while measuring the beacon error rate PERb and the data error rate PERd by the error rate measurement unit 130 (step S943), until the beacon error rate PERb is not higher than the data error rate PERd (until improvement). Wait (step S944). During this time, when the timer 150 times out, the standby process ends (step S945). When the standby process ends in this way, the beacon period management unit 140 returns its own beacon period TNWx to the state before correction in step S922 (step S946).

  FIG. 8 is a diagram showing an example of the improvement standby process (step S950) of FIG. 6 in the embodiment of the present invention. Here, after the timer 150 is reset (step S951), the error rate measurement unit 130 measures the beacon error rate PERb and the data error rate PERd (step S953), and the beacon error rate PERb is a data error. It waits until it is not higher than the rate PERd (until it is improved) (step S954). When the standby process is terminated by improving the beacon error rate PERb, the beacon period management unit 140 corrects its own beacon period TNWx to be the same as the other beacon periods TNWy (step S958), and waits for improvement. The process ends. During this time, when the timer 150 times out, the improvement standby process is terminated as it is (step S955).

  As described above, according to the procedure examples of FIGS. 6 to 8 in the embodiment of the present invention, the beacon period TNWy from the radio communication device of the other radio network causing the beacon collision is longer than the own beacon period TNWx. If it is long, it can wait for an improvement in the error rate PERb of the beacon and maintain that state in the improved stage. On the other hand, when the other beacon period TNWy cannot be specified or the specified other beacon period TNWy is not longer than its own beacon period TNWx, the beacon error rate PERb is higher than the data error rate PERd. It is possible to promote improvement of the error rate of the beacon by delaying its own beacon period, and to maintain the state in the improved stage.

  In addition, although the example which matches a beacon period with the wireless communication apparatus with the slowest beacon period was demonstrated here, you may comprise this so that a beacon period may be matched with the wireless communication apparatus with the earliest beacon period. In this case, in step S922 in FIG. 5 and step S942 in FIG. 7, the beacon period management unit 140 corrects its beacon period TNWx to be shorter (earlier). Further, in step S937 in FIG. 6, if another beacon period TNWy is shorter than its own beacon period TNWx, an improvement standby process (step S950) is performed. If not, or if a beacon is not found in step S934, forced Adjustment processing (step S940) is performed.

  Further, the embodiment of the present invention shows an example for embodying the present invention, and has a corresponding relationship with the invention specific matter in the claims as shown below, but is not limited thereto. However, various modifications can be made without departing from the scope of the present invention.

  That is, in claims 1 to 3, the beacon period detection means corresponds to, for example, the beacon period detection unit 120. Also, the beacon period management means corresponds to the beacon period management unit 140, for example. The propagation loss measuring means corresponds to the error rate measuring unit 130, for example. A beacon generating unit corresponds to the beacon generating unit 180, for example.

  Further, in claims 5 and 6, the procedure for measuring the propagation loss of beacons and data from a predetermined wireless communication device among the plurality of wireless communication devices corresponds to, for example, step S911. In addition, when the beacon propagation loss is larger than the data propagation loss, the procedure for correcting the own beacon period in a predetermined direction corresponds to, for example, step S922. Further, the procedure for returning the beacon period before correction from the state where the propagation loss of the beacon is larger than the propagation loss of the data corresponds to, for example, steps S924 and S926.

  The processing procedure described in the embodiment of the present invention may be regarded as a method having a series of these procedures, and a program for causing a computer to execute these series of procedures or a recording medium storing the program May be taken as

It is a figure which shows a mode that a different radio | wireless network adjoins in the radio | wireless communications system which is embodiment of this invention. It is a figure which shows the relationship between the beacons by a different wireless network in embodiment of this invention. It is a figure which shows the example of 1 structure of the radio | wireless communication apparatus 100 in embodiment of this invention. It is a figure which shows the example of 1 structure of the beacon period table 160 in embodiment of this invention. It is a figure which shows an example of the operation | movement procedure of the radio | wireless communication apparatus 100 in embodiment of this invention. It is a figure which shows the other example of the operation | movement procedure of the radio | wireless communication apparatus 100 in embodiment of this invention. It is a figure which shows an example of the forced adjustment process (step S940) of FIG. 6 in embodiment of this invention. It is a figure which shows an example of the improvement standby | waiting process (step S950) of FIG. 6 in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 Wireless network 11-14, 21-23, 100 Wireless communication apparatus 101 Antenna 102 Switch 110 Reception part 120 Beacon period detection part 130 Error rate measurement part 140 Beacon period management part 150 Timer 160 Beacon period table 161 Device identifier 162 Beacon period 163 Beacon payload 180 Beacon generator 190 Transmitter

Claims (6)

In a wireless communication system in which a plurality of wireless communication devices are autonomously distributed to form a network,
Each of the plurality of wireless communication devices is
Beacon period detection means for detecting a beacon period from beacon signals received from the plurality of wireless communication devices;
Beacon period management means for managing its beacon period so that the detected beacon period is aligned with the radio communication device most shifted in a predetermined direction;
Propagation loss measuring means for measuring beacon and data propagation loss from a predetermined wireless communication device among the plurality of wireless communication devices;
Comprising beacon generating means for generating a beacon based on its own beacon period;
The wireless communication system, wherein the beacon period managing means keeps shifting its own beacon period in the predetermined direction until the state is resolved in a state where the propagation loss of the beacon is larger than the propagation loss of the data. . A wireless communication device in a wireless communication system in which a plurality of wireless communication devices are autonomously distributed to form a network,
Beacon period detection means for detecting a beacon period from beacon signals received from the plurality of wireless communication devices;
Beacon period management means for managing its beacon period so that the detected beacon period is aligned with the radio communication device most shifted in a predetermined direction;
Propagation loss measuring means for measuring beacon and data propagation loss from a predetermined wireless communication device among the plurality of wireless communication devices;
Comprising beacon generating means for generating a beacon based on its own beacon period;
The beacon period managing means keeps shifting its own beacon period in the predetermined direction until the state is resolved in a state where the propagation loss of the beacon is larger than the propagation loss of the data. . A wireless communication device in a wireless communication system in which a plurality of wireless communication devices are autonomously distributed to form a network,
Beacon period detection means for detecting a beacon period from beacon signals received from the plurality of wireless communication devices;
Beacon period management means for managing its beacon period so that the detected beacon period is aligned with the radio communication device most shifted in a predetermined direction;
Propagation loss measuring means for measuring beacon and data propagation loss from a predetermined wireless communication device among the plurality of wireless communication devices;
Comprising beacon generating means for generating a beacon based on its own beacon period;
The beacon period management means searches for a beacon from another wireless communication device that forms a network other than the network, and the beacon period of the beacon is shifted in the predetermined direction from the beacon period of the beacon. When the state is canceled from the state where the propagation loss of the beacon measured by the loss measuring means is larger than the propagation loss of the data, the own beacon period is changed to the beacon period of the beacon from the other wireless communication device. A wireless communication apparatus that corrects to match. The beacon period managing means is configured to detect the propagation loss of the beacon when the beacon from the other wireless communication apparatus is not searched or when the beacon period of the searched beacon is not shifted in the predetermined direction from the own beacon period. 4. The wireless communication apparatus according to claim 3, wherein said beacon cycle is continuously shifted in said predetermined direction until said state is resolved in a state where the number of transmission losses is greater than said data transmission loss. Among a plurality of wireless communication devices that autonomously distribute and form a network, in a wireless communication device that manages its beacon cycle so that the beacon cycle is aligned with the wireless communication device whose beacon cycle is most shifted in a predetermined direction,
A procedure for measuring propagation loss of beacons and data from a predetermined wireless communication device among the plurality of wireless communication devices;
A procedure for correcting the beacon period in a predetermined direction when the propagation loss of the beacon is larger than the propagation loss of the data;
A beacon cycle management method comprising: a procedure for returning the beacon cycle of the beacon to the pre-correction when the beacon is lost from a state in which the propagation loss of the beacon is greater than the propagation loss of the data. Among a plurality of wireless communication devices that autonomously distribute and form a network, in a wireless communication device that manages its beacon cycle so that the beacon cycle is aligned with the wireless communication device whose beacon cycle is most shifted in a predetermined direction,
A procedure for measuring propagation loss of beacons and data from a predetermined wireless communication device among the plurality of wireless communication devices;
A procedure for correcting the beacon period in a predetermined direction when the propagation loss of the beacon is larger than the propagation loss of the data;
A program for causing a computer to execute a procedure for returning its own beacon period to the pre-correction when the beacon propagation loss is larger than the data propagation loss.

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