JP5298294B2 - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication system for improving through-put, while avoiding collisions. <P>SOLUTION: When a burst-mode transition report is received from an access point AP, radio apparatuses 6, 7, 12, 13 constituting a group Gr1 try packet transmission to the access point AP. When the radio apparatus 7, for example, acquires packet transmission right, the apparatus transmits the packet to the access point AP. When the packet from the radio apparatus 7 is received, the radio apparatuses 6, 12, 13 performs transition to burst states so as to continuously transmit the packets to the access point AP, in response to priority order among the radio apparatuses 6, 12, 13. The access point AP successively receives the packets from the radio apparatuses 7, 6, 12, 13 and transmits block confirmation responses to the radio apparatuses 6, 7, 12, 13, which indicate success/failure of the reception of the packets from the radio apparatuses 7, 6, 12, 13. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a wireless communication system, and more particularly to a wireless communication system in which a plurality of wireless devices continuously transmit packets to one wireless device.

  In a wireless communication system, when a plurality of wireless devices existing in an interference area transmit and receive packets simultaneously using the same wireless medium, packet collision occurs.

  In order to avoid such packet collision, a wireless communication system uses a MAC (Media Access Control) protocol that controls access to wireless media by each wireless device. For example, a wireless LAN (Local Area Network) of the IEEE 802.11 standard uses a method called CSMA / CA (Carrier Sense Multiple Access Avidity Aid) as a MAC protocol.

  In CSMA / CA, each wireless device avoids a collision between a wireless device that intends to transmit a packet (carrier sense function) and a wireless device that wants to communicate at the same time. Function (back-off function).

  With these functions, each wireless device communicates so as to avoid a collision between a packet transmitted by another wireless device and a packet that the wireless device intends to transmit.

However, the following problems have been pointed out as problems of this MAC protocol.
(1) When the number of wireless devices attempting to communicate at the same time increases, packet collision becomes unavoidable and throughput decreases.
(2) Protocol processing for avoiding collisions and overhead due to headers added to packets are large. In particular, when a packet having a small size is transmitted, the overhead ratio increases and the effective use of the bandwidth is impaired.

  In order to solve these problems, a technique called packet burst transmission has been proposed (Non-Patent Document 1). In this technology, when a certain wireless device transmits a packet to another wireless device, if there is another packet addressed to the same wireless device after confirming the successful transmission of one packet, the predetermined time is determined. During this period, these packets are continuously transmitted.

  More specifically, it is assumed that the wireless device A holds packets PKT1 to PKT4 addressed to the wireless device B. Assume that the wireless device A transmits a packet PKT1 according to CSMA / CA (carrier sense of DIFS seconds + backoff of CW seconds). In normal CSMA / CA, after completing the transmission of the packet PKT1, the wireless device A once again accesses the channel according to CSMA / CA and transmits the packet PKT2.

  On the other hand, in burst transmission, the wireless device A confirms the successful transmission of the packet PKT1 (that is, receives ACK (Acknowledge) from the wireless device B), and then immediately transmits the packet PKT2 after a certain time (SIFS). . Further, if the transmission of the packet PKT2 is successful, the wireless device A continuously transmits the packet PKT3 and the packet PKT4 within the predetermined parameter time T.

  In Non-Patent Document 1, a method of performing a reception confirmation (block ACK) at a time from the receiving side after transmitting a plurality of packets continuously without transmitting an ACK for each continuously transmitted packet. Are also stipulated.

  In addition, a technique for combining and transmitting a plurality of packets has been proposed (Non-Patent Document 2). As described above, this technique is a technique for combining and transmitting a plurality of packets when a plurality of packets are transmitted from one radio apparatus to another radio apparatus.

  Non-Patent Document 2 defines a method for combining packets in different packet units such as MPDU (MAC Protocol Data Unit) and MSDU (Master Storage Data Unit).

  In Non-Patent Document 2, only packet combination in one-to-one communication is defined, but a method of combining a plurality of packets from one wireless device to a plurality of wireless devices is also proposed (Non-patent Document). Reference 3).

  When the burst transmission or packet combination method described above is used, one wireless device can transmit a plurality of packets with one channel access, and the number of channel accesses required for packet transmission of each wireless device can be reduced. Thereby, the load applied to the channel can be reduced. In addition, processing overhead (for example, DIFS and CW period) necessary to transmit one packet can be reduced. Furthermore, if packet combination is used, the overhead of the MAC header necessary for transmitting one packet can be reduced.

IEEE Standard for Information technology − Telecommunications and information exchange between systems − Local and metropolitan area networks − Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements. Draft STANDARD for Information Technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment: Enhancements for Higher Throughput. K. Lee, S. Yun, I. Kang, and H. Kim, “Hop-by-Hop Frame Aggregation for VoIP on Multi-Hop Wireless Networks,” in Proc. IEEE ICC 2008, Beijing, China, May 2008.

  However, since the above-described conventional method targets only packets generated from the same wireless device, it is difficult to apply the above-described conventional method between a plurality of transmission packets held by a plurality of wireless devices. is there. As a result, there is a problem that throughput when a plurality of wireless devices transmit a plurality of packets to one transmission destination is reduced.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless communication system capable of improving throughput while avoiding a collision.

  According to the present invention, the wireless communication system includes a first wireless device and a plurality of second wireless devices. The first radio apparatus determines whether or not to shift to a burst mode in which a plurality of radio apparatuses continuously transmit packets in time division, and transmits a burst mode shift notification when determining to shift to the burst mode. And receive packets in burst mode. The plurality of second wireless devices continuously transmit packets to the first wireless device in time division in response to reception of the burst mode transition notification from the first wireless device.

  Preferably, the first wireless device shifts to a burst mode when the throughput of wireless communication is smaller than the first threshold and the number of second wireless devices that access the first wireless device is larger than the second threshold. Judge that.

  Preferably, the first wireless device is configured such that when the throughput is equal to or higher than the first threshold value, or when the number of second wireless devices accessing itself is equal to or lower than the second threshold value, or the throughput is equal to the first threshold value. When the number of second wireless devices accessing the device is equal to or smaller than the second threshold value, burst mode release notification for notifying burst mode release is transmitted to the plurality of second wireless devices. Each of the plurality of second wireless devices releases the burst mode in response to the burst mode release notification.

  Preferably, the first wireless device determines whether to divide the plurality of second wireless devices into a group based on wireless communication quality between the plurality of second wireless devices, and the plurality of second wireless devices When it is determined that the wireless devices are divided into groups, a plurality of packets can be detected and decoded between the second wireless devices belonging to the same group based on the wireless communication quality between the plurality of second wireless devices. The second wireless devices are divided into groups, and the result of the grouping is transmitted to the plurality of second wireless devices together with the burst mode transition notification. Each of the plurality of second wireless devices receives the burst mode transition notification and the grouping result, and cooperates with the other second wireless devices belonging to the same group to continuously transmit packets in a time division manner. To the wireless device.

  Preferably, when the first wireless device determines that the plurality of second wireless devices cannot be divided into groups, the first wireless device transmits a burst mode release notification instructing release of the burst mode to the plurality of second wireless devices. To do. Each of the plurality of second wireless devices releases the burst mode in response to the burst mode release notification.

  Preferably, when the first wireless device determines to divide the plurality of second wireless devices into groups, the number of second wireless devices belonging to each group is equal to or less than an allowable value. Yes, and divide into as few groups as possible, and determine the priority in which each second wireless device transmits a packet in each group that has been grouped. The identifier of the second wireless device and the priority of each second wireless device in each group are transmitted to the plurality of second wireless devices together with the burst mode transition notification. Each of the plurality of second wireless devices receives the burst mode transition notification, the group name, the identifier of the second wireless device belonging to each group, and the priority of each second wireless device in each group, and When it is detected that another second wireless device belonging to the same group has transmitted a packet to the first wireless device, the packet is transmitted to the first wireless device according to its own priority.

  Preferably, n (n is an integer of 2 or more) second wireless devices belonging to the same group hold packets transmitted by all of the n second wireless devices to the first wireless device. In this case, packets are transmitted to the first wireless devices in order of priority, and i (i is a positive integer) second wireless devices among the n second wireless devices are the first wireless devices. When the packet to be transmitted is not held, the packet is transmitted to the first wireless device according to the priority order of the remaining second wireless devices excluding the i second wireless devices.

  Preferably, the i second wireless devices wait until all of the ni second wireless devices transmit packets to the first wireless device.

  Preferably, each of n (n is an integer of 2 or more) second wireless devices belonging to the same group has received a packet transmitted from the second wireless device belonging to another group to the first wireless device. When waiting, all the second wireless devices belonging to other groups transmit packets to the first wireless device.

  Preferably, when the first wireless device receives a packet in the burst mode, the first wireless device transmits an acknowledgment indicating that the packet has been received to the second wireless device that has transmitted the packet in the burst mode.

  In the wireless communication system according to the present invention, it is determined whether or not the first wireless device shifts to the burst mode, and when it is determined to shift to the burst mode, a burst mode shift notification is transmitted to the plurality of second wireless devices. To do. Then, the plurality of second radio apparatuses continuously transmit packets to the first radio apparatus in time division in response to the burst mode transition notification from the first radio apparatus.

  Therefore, according to the present invention, throughput can be improved while avoiding collision of a plurality of packets transmitted from a plurality of second radio apparatuses.

1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. It is a block diagram of the radio | wireless apparatus shown in FIG. It is a block diagram of the access point shown in FIG. It is a block diagram of a signal reception table. It is a block diagram of a reception condition table. It is a figure for demonstrating the preparation method of a signal reception table. It is a figure which shows the specific example of a reception condition table. It is a figure which shows the specific example of group division. It is a figure which shows the specific example of the cooperative burst continuous transmission method using backoff time. It is a figure which shows the other specific example of the cooperative burst continuous transmission method using backoff time. It is a figure which shows the specific example of the cooperative burst continuous transmission method using AIFS. It is a figure which shows the other specific example of the cooperation burst continuous transmission method using AIFS. It is a figure which shows the specific example of the cooperative burst continuous transmission method which does not use block confirmation response Block ACK. It is a flowchart for demonstrating operation | movement of the radio | wireless apparatus which has a transmission packet in burst mode. It is a flowchart for demonstrating operation | movement of the radio | wireless apparatus which does not have a transmission packet in burst mode. It is a flowchart for demonstrating operation | movement of an access point.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. Referring to FIG. 1, a wireless communication system 100 according to an embodiment of the present invention includes an access point AP and wireless devices 1-16.

  The access point AP and the wireless devices 1 to 16 are arranged in a wireless communication space. More specifically, the wireless devices 1 to 16 are disposed within a communication range of the access point AP and are disposed within a range in which wireless communication can be directly performed.

  The access point AP performs wireless communication with each of the wireless devices 1-16. Then, the access point AP determines whether or not the communication method between the wireless devices 1 to 16 should be shifted to a burst mode in which a plurality of wireless devices continuously transmit packets in a time division manner.

  When the access point AP determines that the communication method with the wireless devices 1 to 16 should be shifted to the burst mode, the access point AP generates a burst mode transition notification and transmits it to the wireless devices 1 to 16. Then, the access point AP performs wireless communication with the wireless devices 1 to 16 in the burst mode by a method described later.

  When the access point AP determines that the communication method with the wireless devices 1 to 16 should not be shifted to the burst mode, the access point AP generates a burst mode release notification and transmits the notification to the wireless devices 1 to 16. Then, the access point AP performs wireless communication with the wireless devices 1 to 16 in accordance with a normal communication method.

  Each of the wireless devices 1 to 16 performs wireless communication with the access point AP. And each of the radio | wireless apparatuses 1-16 will perform radio | wireless communication with access point AP by burst method by the method mentioned later, if the burst mode transfer notification is received from access point AP.

  Further, when each of the wireless devices 1 to 16 receives the burst mode release notification from the access point AP, the wireless device 1 to 16 switches the communication method from the burst mode to the normal communication method, and performs wireless communication with the access point AP according to the normal communication method.

  FIG. 2 is a configuration diagram of the wireless device 1 shown in FIG. Referring to FIG. 2, the wireless device 1 includes an antenna 21, a transmission / reception unit 22, a table creation unit 23, a signal reception table 24, a communication control unit 25, and a communication unit 26.

  The antenna 21 receives a packet from the access point AP or the other wireless devices 2 to 16 and outputs the received packet to the transmission / reception means 22. Further, the antenna 21 receives the beacon frame Bcon from the access point AP and outputs the received beacon frame Bcon to the transmission / reception means 22.

  Furthermore, the antenna 21 receives a packet from the transmission / reception means 22 and transmits the received packet to the access point AP.

  When the antenna 21 receives a packet from the other wireless devices 2 to 16, the transmission / reception means 22 detects the received signal strength RSSI when the packet is received and the transmission source address (= MAC address) of the packet. The detected received signal strength RSSI and the transmission source address are associated with each other and output to the table creating means 23.

  Further, the transmission / reception means 22 outputs the packet received from the antenna 21 to the communication control means 25.

  Further, the transmission / reception means 22 receives the beacon frame Bcon from the antenna 21 and outputs the received beacon frame Bcon to the communication control means 25.

  Further, the transmission / reception means 22 receives a packet from the communication means 26 and transmits the received packet to the access point AP via the antenna 21. In this case, the transmission / reception unit 22 transmits the packet received from the communication unit 26 to the access point AP in the burst mode or accesses the packet received from the communication unit 26 in the normal communication mode according to the control from the communication control unit 25. Send to point AP.

  The table creating unit 23 receives the reception signal strength RSSI and the transmission source address associated with each other from the transmission / reception unit 22. Then, the table creation unit 23 calculates an average value RSSI_AVE of the reception signal strength RSSI for each transmission source wireless device based on the reception signal strength RSSI and the transmission source address. In this case, the table creation means 23 calculates the average value RSSI_AVE of the received signal strength RSSI detected within a few seconds.

  The table creation means 23 calculates the average value RSSI_AVE of the received signal strength RSSI for each wireless device, and creates the signal reception table 24 by associating the average value RSSI_AVE with the source address.

  The signal reception table 24 stores each transmission source wireless device and the average value RSSI_AVE of the received signal strength RSSI in association with each other.

  The communication control means 25 reads the signal reception table 24 every cycle Treport, and outputs the read signal reception table 24 to the communication means 26.

  The communication control means 25 receives the beacon frame Bcon from the transmission / reception means 22. Then, when the beacon frame Bcon received from the transmission / reception unit 22 includes a burst mode transition notification, the communication control unit 25 controls the transmission / reception unit 22 to transmit the packet to the access point AP in the burst mode by a method described later. . In addition, when the beacon frame Bcon received from the transmission / reception unit 22 includes a burst mode release notification, the communication control unit 25 causes the transmission / reception unit 22 to transmit the packet to the access point AP by a normal communication method by a method described later. Control. Further, the communication control unit 25 outputs the packet received from the transmission / reception unit 22 to the communication unit 26.

  The communication unit 26 receives the signal reception table 24 from the communication control unit 25 for each cycle Treport. Upon receiving the signal reception table 24, the communication unit 26 generates a packet including the received signal reception table 24 in the data portion, and outputs the generated packet to the transmission / reception unit 22.

  This period Treport is determined by the assumed moving environment of the wireless devices 1 to 16. For example, in an environment where the wireless device does not move at high speed, such as a wireless LAN, the period Treport is set to about several seconds (for example, 1 second).

  The communication unit 26 receives a packet from the communication control unit 25. Then, when the transmission destination of the received packet is the wireless device 1, the communication unit 26 receives the packet.

  Further, the communication unit 26 generates a packet including normal data in the data part, and outputs the generated packet to the transmission / reception unit 22.

  Note that each of the wireless devices 2 to 16 illustrated in FIG. 1 has the same configuration as the wireless device 1 illustrated in FIG. 2.

  FIG. 3 is a configuration diagram of the access point AP shown in FIG. Referring to FIG. 3, access point AP includes an antenna 31, a transmission / reception unit 32, a communication control unit 33, a table creation unit 34, a reception status table 35, and a communication unit 36.

  The antenna 31 receives packets from the wireless devices 1 to 16 and outputs the received packets to the transmission / reception means 32. The antenna 31 receives a packet from the transmission / reception means 32 and transmits the received packet to the wireless devices 1 to 16. Furthermore, the antenna 31 receives the beacon frame Bcon from the transmission / reception means 32 and transmits the received beacon frame Bcon to the wireless devices 1 to 16.

  The transmission / reception means 32 receives a packet from the antenna 31 and outputs the received packet to the communication control means 33. The transmission / reception unit 32 receives a packet from the communication unit 36 and outputs the received packet to the antenna 31. Further, when receiving the beacon frame Bcon from the communication control unit 33, the transmission / reception unit 32 transmits the received beacon frame Bcon to the wireless devices 1 to 16 via the antenna 31.

  The communication control unit 33 receives a packet from the transmission / reception unit 32. Then, the communication control unit 33 outputs the packet to the table creation unit 34 when the received packet includes the signal reception table 24. On the other hand, the communication control unit 33 outputs the packet to the communication unit 36 when the received packet includes normal data.

  Further, the communication control unit 33 generates a beacon frame Bcon and transmits the generated beacon frame Bcon to the wireless devices 1 to 16 via the transmission / reception unit 32 and the antenna 31.

  Further, the communication control means 33 detects the number N (N is a positive integer) of wireless devices that access the access point AP by detecting the transmission source of the packet received from the transmission / reception means 32. And the communication control means 33 detects the throughput THP when transmitting the packet from the radio | wireless apparatuses 1-16 to the access point AP by measuring the bit number of the data received from the transmission / reception means 32 per second.

  Then, the communication control means 33 determines whether or not to shift to the burst mode based on the detected number N of wireless devices and the throughput THP. More specifically, the communication control unit 33 determines to shift to the burst mode when the number N of wireless devices is larger than the threshold value Nth and the throughput THP is smaller than the threshold value THPth. Further, the communication control means 33 is configured such that when the number N of wireless devices is equal to or less than the threshold value Nth, or when the throughput THP is equal to or greater than the threshold value THPth, or the number N of wireless devices is equal to or less than the threshold value Nth. When the throughput THP is equal to or higher than the threshold value THPth, it is determined not to shift to the burst mode.

  Note that the threshold value Nth is, for example, 10, and the threshold value THPth is, for example, 3 Mbps.

  When the communication control unit 33 determines to shift to the burst mode, the communication control unit 33 refers to the reception status table 35 and further determines whether or not the wireless devices 1 to 16 can be grouped by a method described later.

  When the communication control unit 33 determines that the wireless devices 1 to 16 can be grouped, the communication control unit 33 refers to the reception status table 35 to group the wireless devices 1 to 16 by a method described later, and is a result of the grouping. Generate group structure. Then, the communication control unit 33 generates a burst mode transition notification, includes the generated burst mode transition notification and the group configuration in the beacon frame Bcon, and transmits the burst mode transition notification to the radio apparatuses 1 to 16 via the transmission / reception unit 32 and the antenna 31. .

  On the other hand, when it is determined that the wireless devices 1 to 16 cannot be grouped, the communication control unit 33 does not generate a burst mode transition notification and outputs nothing to the wireless devices 1 to 16.

  When the communication control means 33 determines not to shift to the burst mode, the communication control means 33 generates a burst mode cancellation notification, includes the generated burst mode cancellation notification in the beacon frame Bcon, and wirelessly transmits via the transmission / reception means 32 and the antenna 31. Transmit to devices 1-16.

  The table creation unit 34 receives a packet from the communication control unit 33 and detects the signal reception table 24 included in the received packet. Then, the table creation means 34 creates a reception status table 35 based on the detected signal reception table 24 by a method described later.

  The reception status table 35 stores the average value RSSI_AVE of the received signal strength RSSI between the wireless devices 1 to 16 as the reception status.

  The communication unit 36 receives a packet from the communication control unit 33, and accepts the packet when the received packet includes data addressed to the access point AP.

  The communication unit 36 generates a packet addressed to the wireless device (any one of the wireless devices 1 to 16), and outputs the generated packet to the transmission / reception unit 32.

  FIG. 4 is a configuration diagram of the signal reception table. Referring to FIG. 4, signal reception table 24 includes an address of the wireless device and an average value RSSI_AVE of received signal strength RSSI. The wireless device address and the average value RSSI_AVE are associated with each other.

  The address of the wireless device is composed of the MAC address of the packet transmission source. The average value RSSI_AVE of the received signal strength RSSI is an average value of the received signal strength when the wireless device that creates the signal reception table 24 receives a packet from the wireless device specified by the address of the wireless device.

  FIG. 5 is a configuration diagram of the reception status table. Referring to FIG. 5, reception status table 35 includes address 1 of the wireless device, address 2 of the wireless device, and average value RSSI_AVE of received signal strength RSSI.

  Each of the wireless device address 1 and the wireless device address 2 is composed of the MAC addresses of the wireless devices 1 to 16. The average value RSSI_AVE of the received signal strength RSSI is composed of the average value of the received signal strength in the wireless device that has received the packet.

  FIG. 6 is a diagram for explaining a method of creating the signal reception table 24. In FIG. 6, the creation of the signal reception table 24 in the wireless device 1 will be described.

  With reference to FIG. 6, the wireless device 1 initially holds a signal reception table 24-0 (see FIG. 6A).

  When receiving the packet PKT1 from the wireless device 2 via the antenna 21, the transmission / reception means 22 of the wireless device 1 detects the received signal strength RSSI1 when the packet PKT1 is received, and transmits the packet PKT1 (= wireless device) 2) MAC address MAC2 is detected.

  Then, the transmission / reception means 22 of the wireless device 1 associates the detected received signal strength RSSI1 and the MAC address MAC2 with each other and outputs the associated information to the table creation means 23.

  The transmission / reception means 22 of the wireless device 1 detects the received signal strength RSSI and the MAC address MAC2 for each of a plurality of packets received from the wireless device 2 via the antenna 21 for several seconds, and the detected received signal strength RSSI. And the MAC address MAC2 are output to the table creation means 23 in association with each other.

  Then, the table creation unit 23 of the wireless device 1 receives the plurality of received signal strengths RSSI and the MAC address MAC2 from the transmission / reception unit 22, and calculates an average value RSSI_AVE1 = 10 dBm of the received plurality of received signal strengths RSSI. Then, the table creation means 23 of the wireless device 1 stores the MAC address MAC2 in the field of the wireless device address of the signal reception table 24-0, and averages the RSSI_AVE1 = 10 dBm average received signal strength corresponding to the MAC address MAC2. The signal reception table 24-1 (see FIG. 6B) is created by storing in the value column.

  Thereafter, the transmission / reception means 22 and the table creation means 23 of the wireless device 1 repeatedly execute the above-described operation for the packets received from each of the wireless devices 3 to 16, and the signal reception table 24-2 (see FIG. 6C). ).

  FIG. 7 is a diagram illustrating a specific example of the reception status table 35. The transmission / reception means 32 of the access point AP receives a packet including the signal reception table 24-2 from the wireless device 1 via the antenna 31 and outputs the received packet to the communication control means 33.

  Then, the communication control unit 33 of the access point AP receives the packet from the transmission / reception unit 32 and outputs the packet to the table creation unit 34 because the received packet includes the signal reception table 24-2.

  The table creation unit 34 of the access point AP receives the packet from the communication control unit 33, and detects the source MAC address MAC1 and the signal reception table 24-2 from the received packet.

  Then, the table creation means 34 of the access point AP calculates the average value RSSI_AVE of the received signal strength RSSI between the wireless device 1 and the wireless devices 2 to 16 based on the MAC address MAC1 and the signal reception table 24-2. 10 dBm, 8 dBm, 9 dB,..., 12 dBm, 3 dBm, 5 dBm, and 7 dBm are detected.

  Then, the table creation unit 34 of the access point AP stores 10 dBm in a column (first row and second column in FIG. 7) where the MAC address MAC1 and the MAC address MAC2 intersect. Further, the table creation unit 34 of the access point AP stores 8 dBm in a column where the MAC address MAC1 and the MAC address MAC2 intersect. Similarly, the table creation unit 34 of the access point AP stores 9 dBm,..., 12 dBm, 3 dBm, 5 dBm, and 7 dBm in columns where the MAC address MAC1 and the MAC addresses MAC3 to MAC16 intersect.

  As a result, the first row of the reception status table 35-1 is completed.

  Based on the signal reception table 24 received from each of the wireless devices 2 to 16, the table creation means 34 of the access point AP stores the average value RSSI_AVE of the received signal strength RSSI between the two wireless devices in the same manner. The reception status table 35-1 is completed.

  A method for determining whether or not the access point AP can be grouped will be described. The communication control means 33 of the access point AP refers to the reception status table 35 and determines whether or not the wireless devices 1 to 16 can be grouped. More specifically, the communication control means 33 of the access point AP sets a threshold value RSSIth of the average value RSSI_AVE of the received signal strength RSSI, and has a plurality of average values RSSI_AVE larger than the set threshold value RSSIth. If wireless devices exist, it is determined that grouping is possible.

  For example, when the reception status table 35 includes the reception status table 35-1 shown in FIG. 7, if the threshold RSSIth is RSSIth = 0 dBm, the communication control means 33 of the access point AP will Since all of them have an average value RSSI_AVE of the received signal strength RSSI larger than the threshold RSSIth = 0 dBm, it is determined that all of the wireless devices 1 to 16 can be grouped into the same group.

  Further, if the threshold RSSIth = 5 dBm, the communication control means 33 of the access point AP has a received signal strength RSSI in which all of the wireless devices 1, 2, 13, 16 are larger than the threshold RSSIth = 5 dBm. Therefore, it is determined that the wireless devices 1, 2, 13, and 16 can be grouped into the same group.

  In this case, the wireless devices 3, 4, 14, and 15 cannot be grouped into the same group. The wireless device 3 has an average value RSSI_AVE = 8 dBm larger than the threshold RSSIth = 5 dBm with the wireless device 1, but the average value RSSI_AVE with the wireless device 2 is larger than the threshold RSSIth = 5 dBm. This is because it is a small 3 dBm. The wireless device 4 has an average value RSSI_AVE = 9 dBm larger than the threshold RSSIth = 5 dBm with the wireless device 1, but the average value RSSI_AVE with the wireless device 2 has a threshold RSSIth = 5 dBm. This is because it is smaller than 4 dBm. Further, the wireless device 14 has an average value RSSI_AVE = 3 dBm smaller than the threshold value RSSIth = 5 dBm with the wireless device 1. Furthermore, wireless device 15 has an average value RSSI_AVE = 5 dBm which is equal to or less than threshold RSSIth = 5 dBm between wireless devices 1 and 2.

  On the other hand, the communication control means 33 of the access point AP determines that grouping is not possible when there is no wireless device that can be grouped with any wireless device.

  In this way, the communication control means 33 of the access point AP can determine whether or not grouping is possible by determining whether or not there are a plurality of wireless devices having an average value RSSI_AVE that is greater than the threshold value RSSIth. Determine whether.

  The communication control means 33 of the access point AP sets the threshold RSSIth so that the wireless devices belonging to the same group can detect and decode each other's packets. This is to ensure that each wireless device belonging to the same group can receive a packet transmitted from another wireless device in the same group in packet transmission in a burst mode described later.

  Subsequently, a grouping method will be described.

[Grouping method 1]
This grouping method 1 is a method in which the number of wireless devices in a group is equal to or smaller than an allowable value and the number of generated groups is reduced as much as possible. In the grouping method 1, the communication control means 33 of the access point AP generates the number of wireless devices in each group that is equal to or less than the maximum number Nmax of wireless devices that can belong to the same group. A grouping pattern that minimizes the number of groups Ng is extracted. The maximum number Nmax is set in advance in the communication control means 33 of the access point AP.

  For example, when the reception status table 35 includes the reception status table 35-1 shown in FIG. 7 and the threshold RSSIth = 0 dBm and Nmax = 4, the communication control means 33 of the access point AP sets Ng = 4. A grouping pattern is extracted. Then, if there is only one type of pattern in which the number of groups Ng is minimum, the communication control means 33 of the access point AP sets that one type of pattern as the result of grouping. On the other hand, when there are a plurality of patterns with the smallest group number Ng, the communication control means 33 of the access point AP arbitrarily selects one pattern from the plurality of patterns, and the selected one pattern is grouped. As a result.

[Grouping method 2]
In this grouping method 2, the number of wireless devices in the group is equal to or less than an allowable value, the number of generated groups is reduced as much as possible, and the average received signal strength RSSI between the wireless devices in the group This is a method in which the characteristic of the value RSSI_AVE satisfies the given condition.

  In the grouping method 2, as in the grouping method 1, the communication control means 33 of the access point AP determines the maximum number of wireless devices in which the number of wireless devices in each group can belong to the same group. A grouping pattern that is Nmax or less and has the smallest number of generated groups Ng is extracted.

  Then, if there is only one type of pattern in which the number of groups Ng is minimum, the communication control means 33 of the access point AP sets that one type of pattern as the result of grouping.

  On the other hand, when there are a plurality of patterns with the smallest group number Ng, the communication control means 33 of the access point AP selects one pattern from the plurality of patterns as a grouping result using one of the following criteria: To do.

  STD1) In each pattern, the minimum value of the average value RSSI_AVE between the wireless devices in the group is detected, and the pattern with the maximum detected minimum value is selected as the grouping result.

  STD2) In each pattern, the average value RSSI_AVE between the wireless devices in the group is detected, and the pattern having the maximum detected average value is selected as the grouping result.

[Grouping method 3]
This grouping method 3 is such that the number of wireless devices in the group is less than or equal to an allowable value, the number of generated groups is as small as possible, and the traffic amount of the wireless devices in the group is given. It is a method to satisfy.

  In the grouping method 3, as in the grouping method 1, the communication control means 33 of the access point AP determines the maximum number of wireless devices that can belong to the same group. A grouping pattern that is Nmax or less and has the smallest number of generated groups Ng is extracted.

  Then, if there is only one type of pattern in which the number of groups Ng is minimum, the communication control means 33 of the access point AP sets that one type of pattern as the result of grouping.

  On the other hand, when there are a plurality of patterns with the smallest group number Ng, the communication control means 33 of the access point AP selects one pattern from the plurality of patterns as a grouping result using the following method.

  In each pattern, the sum of the traffic volume of the wireless devices in each group is calculated, and the maximum traffic volume is detected. Then, the pattern having the largest maximum traffic amount is set as a grouping result.

[Grouping method 4]
In this grouping method 4, the number of wireless devices in the group is equal to or less than the allowable value, the number of generated groups is minimized, and the average received signal strength RSSI between the wireless devices in the group is reduced. In this method, the value RSSI_AVE and the traffic volume of the wireless devices in the group satisfy the given conditions.

  In the grouping method 4, as in the grouping method 1, the communication control means 33 of the access point AP determines the maximum number of wireless devices in which the number of wireless devices in each group can belong to the same group. A grouping pattern that is Nmax or less and has the smallest number of generated groups Ng is extracted.

  Then, if there is only one type of pattern in which the number of groups Ng is minimum, the communication control means 33 of the access point AP sets that one type of pattern as the result of grouping.

  On the other hand, when there are a plurality of patterns with the smallest group number Ng, the communication control means 33 of the access point AP selects one pattern from the plurality of patterns as a grouping result using the following method.

The minimum value of the average value RSSI_AVE in the group or the average value of the average values RSSI_AVE is defined as M _RSSI . Also, let the total amount of traffic of the wireless devices in each group be M _Traffic .

_Then, defined by the following equation a new metric _{M C} using _{M RSSI} and _{M Traffic.}

M _C = w _T × M _Traffic + w _R × M _RSSI (1)
In Equation (1), w _T and w _R are coefficients for determining which of the traffic volume and the average value RSSI_AVE of the received signal strength is to be preferentially considered, and are composed of arbitrary values.

Communication control means 33 of the access point AP, in the pattern of the different groupings, it computes the metric M _C within each group using the formula (1). The communication control unit 33 of the access point AP, an average value or the maximum value of the metric M _C in a pattern of distinct groups was calculated, and results of grouping patterns mean value or maximum value was the calculation is maximized To do.

[Grouping method 5]
This grouping method 5 is a method based on the number of wireless devices that can be grouped.

  In the grouping method 5, the communication control means 33 of the access point AP sets all wireless devices as a set of wireless devices to be grouped.

  (1) Then, the communication control means 33 of the access point AP selects one wireless device having the maximum number of wireless devices that can be grouped from all the wireless devices included in the grouping target set. . When there are a plurality of wireless devices with the maximum number of wireless devices that can be grouped, one wireless device is arbitrarily selected from the plurality of wireless devices.

  (2) The communication control means 33 of the access point AP has a large average value RSSI_AVE for this radio apparatus when there are Nmax or more radio apparatuses that can be grouped with the radio apparatus extracted in (1) above. Nmax-1 wireless devices are selected in order from wireless devices that can be grouped, and one group including Nmax wireless devices including the wireless device selected in (1) above is formed. On the other hand, the communication control means 33 of the access point AP, when the number of wireless devices that can be grouped is smaller than Nmax, the wireless devices that are capable of all groups and the wireless devices selected in (1) above. A group consisting of Then, the communication control means 33 of the access point AP removes the wireless device that forms this group from the grouping target set.

  (3) The communication control means 33 of the access point AP repeats the processes (1) and (2) until all wireless devices in the grouping target set are excluded.

  The communication control means 33 of the access point AP groups the wireless devices 1 to 16 using any one of the grouping methods 1 to 5 described above.

  The grouping methods 1 to 5 described above are methods for grouping the wireless devices 1 to 16 so that the number of wireless devices in the group is suppressed to an allowable value or less and the number of groups is minimized. Thus, by grouping the wireless devices 1 to 16 so that the number of groups is minimized, the throughput when the wireless devices 1 to 16 transmit packets to the access point AP can be improved. Because, as will be described later, when wireless devices belonging to the same group continuously transmit packets to the access point AP, and wireless devices belonging to one group continuously transmit packets to the access point AP, Wireless devices belonging to other groups do not transmit packets. That is, channel contention occurs only between groups, and the smaller the number of groups, the higher the throughput of the wireless devices 1 to 16 can be improved.

  The communication control means 33 of the access point AP groups the wireless devices 1 to 16 and then sets the priority of the wireless device in each group. In this case, the access point AP may set the priority randomly, or may set the priority according to the MAC address of the wireless device, the requested traffic amount, and QoS (Quality of Service). More specifically, when the communication control means 33 of the access point AP sets the priority according to the MAC address of the wireless device, for example, the priority is set in ascending order of the MAC address value or in descending order of the MAC address value. Set high. In addition, when setting the priority according to the requested traffic volume, the communication control unit 33 of the access point AP sets the higher priority in descending order of the requested traffic volume. Furthermore, when setting the priority according to the QoS, the communication control means 33 of the access point AP sets the priority higher in descending order of QoS.

  The communication control means 33 of the access point AP generates the group configuration Gcomp when the priority of the wireless device in each group is set. The group configuration Gcomp includes a group name, a group size Gs, an identifier ID (= MAC address) of a wireless device belonging to the same group, and a wireless device priority PRTY in each group. The group size is composed of the number of wireless devices included in the group.

  Then, the communication control means 33 of the access point AP includes the group configuration Gcomp and burst mode transition notification for all groups in the beacon frame Bcon and transmits the beacon frame Bcon to the radio apparatuses 1-16.

  When each of the wireless devices 1 to 16 receives the burst mode transition notification and the group configuration from the access point AP, the wireless devices 1 to 16 cooperate with other wireless devices in a time division manner to continuously transmit packets to the access point AP by a method described later. Send.

  Each of the wireless devices 1 to 16 shifts from the burst mode to the normal communication mode when receiving the burst mode release notification from the access point AP.

  FIG. 8 is a diagram illustrating a specific example of grouping. Referring to FIG. 8, communication control means 33 of access point AP divides radio apparatuses 1 to 16 into four groups Gr1 to Gr4 using any one of grouping methods 1 to 5 described above. To do.

  Then, the communication control means 33 of the access point AP generates a group configuration Gcomp1 = [Gr1 / 4 / MAC6, MAC7, MAC12, MAC13 / MAC6> MAC7> MAC12> MAC13] for the group Gr1. Here, “Gr1” is the name of the group, “4” is the group size of the group Gr1, “MAC6, MAC7, MAC12, MAC13” is the identifier of the wireless device belonging to the same group, “ MAC6> MAC7> MAC12> MAC13 "is the priority PRTY of the wireless device in the group Gr1. Similarly, the communication control means 33 of the access point AP performs group configuration Gcomp2 = [Gr2 / 4 / MAC8, MAC9, MAC10, MAC11 / MAC8> MAC9> MAC10> MAC11] for the groups Gr2 to Gr4, respectively. Gcomp3 = [Gr3 / 4 / MAC1, MAC5, MAC14, MAC15 / MAC1> MAC5> MAC14> MAC15], Gcomp4 = [Gr4 / 4 / MAC2, MAC3, MAC4, MAC16 / MAC2> MAC3> MAC4> MAC16] .

  Then, the communication control means 33 of the access point AP includes the burst mode transition notification and the group configurations Gcomp1 to Gcomp4 in the beacon frame Bcon and transmits them to the wireless devices 1 to 16.

  Then, the wireless devices 1 to 16 receive the burst mode transition notification and the group configurations Gcomp1 to Gcomp4 from the access point AP, and based on the received group configurations Gcomp1 to Gcomp4, the wireless devices 6, 7, 12, 13 are grouped. It is detected that the wireless devices 8 to 11 belong to the group Gr2, the wireless devices 1, 5, 14, and 15 belong to the group Gr3, and the wireless devices 2 to 4, 16 belong to the group Gr4. Further, the wireless devices 1 to 16 detect the priority order of the group to which the wireless devices 1 to 16 belong (group Gr1 to Gr4) based on the group configurations Gcomp1 to Gcomp4.

  A packet transmission method in the burst mode will be described. In the following, a packet transmission method in the burst mode will be described using the group Gr1 shown in FIG. 8 as an example.

[Cooperative burst continuous transmission method 1 of packets in burst mode]
This cooperative burst continuous transmission method 1 uses a back-off time. When the communication control means 25 of the wireless devices 6, 7, 12, 13 receives the beacon frame Bcon received from the access point AP from the access point AP via the antenna 21 and the transmission / reception means 22, the communication control means 25 is included in the received beacon frame. Burst mode transition notification and group configurations Gcomp1 to Gcomp4 are taken out. Then, the communication control means 25 of the wireless devices 6, 7, 12, 13 determines that the group Gr1 is composed of the wireless devices 6, 7, 12, 13 based on the extracted group configuration Gcomp1, It is detected that 7, 12, and 13 belong to the group Gr1, and that the priority is higher in the order of the wireless device 6, the wireless device 7, the wireless device 12, and the wireless device 13.

  Then, the communication control means 25 of the wireless devices 6, 7, 12, 13 detects the first packet transmission in the group Gr1 based on the burst mode transition notification and the detection result, and then transmits the packet in the cooperative burst continuous transmission mode. The transmission / reception means 22 is controlled to transmit to the access point AP.

  Further, the communication control means 25 of the wireless devices 6, 7, 12, and 13 is based on the group configurations Gcomp2 to Gcomp4, the wireless devices 8 to 11 belong to the group Gr2, and the wireless devices 1, 5, 14, and 15 belong to the group Gr3. It is detected that the wireless devices 2 to 4 and 16 belong to the group Gr4. Then, the communication control means 25 of the wireless devices 6, 7, 12, 13 outputs the detection result to the transmission / reception means 22.

(I) When all wireless devices in a group hold a transmission packet FIG. 9 is a diagram illustrating a specific example of a cooperative burst continuous transmission method using a back-off time. The communication means 26 of the wireless devices 6, 7, 12, 13 generates a packet addressed to the access point AP and outputs the generated packet to the transmission / reception means 22.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 tries to transmit the packet according to the CSMA / CA scheme. In addition, the transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 tries to receive a packet transmitted from another wireless device.

  As a result, the transmission / reception means 22 of any of the wireless devices 6, 7, 12, and 13 acquires the right to transmit a packet. For example, it is assumed that the transmission / reception means 22 of the wireless device 7 acquires the right to transmit a packet.

  Then, the transmission / reception means 22 of the wireless device 7 transmits a packet PKT_7 composed of the MAC header MH7 and the data DA7 to the access point AP.

  Then, the transmission / reception means 22 of the wireless devices 6, 12, 13 receives the packet transmitted from the wireless device 7.

  Thereafter, the transmission / reception means 22 of the wireless devices 6, 12, and 13 set all their values of IFS (Inter Frame Space Space) called DIFS (Distributed Inter Frame Space) or SIFS (Short Inter Frame Space) to “0”. The back-off time is set according to the priority in the group Gr1, and the state shifts to the burst state. The priority in this case is the priority between the wireless devices 6, 12, and 13 excluding the wireless device 7 that has triggered the transition to the burst state.

  More specifically, the transmission / reception means 22 of the wireless devices 6, 12, and 13 excludes the wireless device 7 that created an opportunity to shift to the burst state among the wireless devices 6, 7, 12, and 13 in the group Gr1. The back-off time of the wireless device having the highest priority among the wireless devices 6, 12, and 13 is set to the time of one slot, and the back-off time of the wireless device having the second highest priority is set to the time of two slots. In the same manner, the back-off time of each wireless device is set in descending order of priority.

  That is, since the priority is higher in the order of the wireless device 6, the wireless device 12, and the wireless device 13 between the wireless devices 6, 12, and 13, the transmission / reception means 22 of the wireless device 6 sets the back-off time to one slot. Then, the transmission / reception means 22 of the wireless device 12 sets the back-off time to 2 slots, and the transmission / reception means 22 of the wireless device 13 sets the back-off time to 3 slots.

  Then, when the wireless device 7 transmits a packet and the back-off time for one slot becomes “0”, the transmission / reception means 22 of the wireless device 6 transmits the packet PKT_6 including the MAC header MH6 and the data DA6 to the access point AP. Send to. At this time, the back-off times in the wireless devices 12 and 13 are counted down to 1 slot and 2 slots, respectively.

  Then, when the wireless device 6 transmits the packet PKT_6 and the backoff time for one slot becomes “0”, the transmission / reception means 22 of the wireless device 12 transmits the packet PKT_12 composed of the MAC header MH12 and the data DA12 to the access point. Send to AP. At this time, the back-off time in the wireless device 13 is counted down to one slot.

  Further, when the wireless device 12 transmits the packet PKT_12 and the backoff time for one slot becomes “0”, the transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 including the MAC header MH13 and the data DA13 to the access point. Send to AP.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 transmit packets PKT_7, PKT_6, PKT_12, PKT_13, respectively, and enter a state of waiting for a block response confirmation block ACK.

  When the transmission / reception means 32 of the access point AP receives the packet PKT_7 from the wireless device 7 for the first time, it sets the back-off time to the slot time corresponding to the number of the wireless devices 6, 7, 12, 13 in the group Gr1.

  That is, the transmission / reception means 32 of the access point AP sets the back-off time to a time corresponding to 4 slots. Then, the transmission / reception means 32 of the access point AP sets all IFSs to “0” and counts down the back-off time every time an empty channel for one slot is detected.

  Further, the communication means 36 of the access point AP generates a block response confirmation Block ACK including successful reception or unsuccessful reception of the packets PKT_7, PKT_6, PKT_12 and PKT_13, and transmits the generated block response confirmation Block ACK to the transmission / reception means 32. Output.

  Then, when the backoff time of the access point AP becomes “0”, the access point AP transmission / reception means 32 determines whether or not SIFS has elapsed from the reception completion time of the last received packet PKT_13.

  The transmission / reception means 32 of the access point AP immediately transmits a block response confirmation block ACK to the wireless devices 6, 7, 12, 13 if SIFS has elapsed since the reception completion time of the packet PKT_13.

  On the other hand, if the SIFS has not elapsed since the reception completion time of the packet PKT_13, the transmission / reception means 32 of the access point AP sends a block response confirmation block ACK when the SIFS has elapsed from the reception completion time of the packet PKT_13. , 12 and 13.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 receives the block confirmation response Block ACK from the access point AP, cancels the burst state, and returns to the cooperative burst continuous transmission mode. Thereafter, when the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 holds the transmission packet, it tries to transmit the packets PKT_ 6, PKT_ 7, PKT_ 12, PKT_ 13 to the access point AP according to the CSMA / CA scheme, respectively.

  In this case, the back-off time and the IFS value are reset to values before the transition to the burst state.

  In addition, the transmission / reception means 22 of the wireless device 7 that first transmitted the packet to the access point AP in the burst mode performs the CW, IFS, and back-off time according to the procedure similar to that of normal CSMA / CA according to the success or failure of the packet transmission result. Set the value.

  The transmission / reception means 22 of each of the wireless devices 6, 7, 12, and 13 shifts to the burst state by the above-described method every time a packet from the wireless device of the same group Gr1 is received during the cooperative burst continuous transmission mode. Cooperative burst continuous transmission is performed.

  As described above, after the wireless device 7 transmits the packet PKT_7 to the access point AP, the wireless devices 6, 12, and 13 continuously transmit the packets PKT_6, PKT_12, and PKT_13 to the access point AP in a time division manner.

  Therefore, it is possible to improve throughput when packets are transmitted to the access point AP while avoiding collision of the packets PKT_6, PKT_12, and PKT_13.

  When the access point AP transmits a packet to the wireless devices 6, 7, 12, and 13, the access point AP transmits the packet to the wireless devices 6, 7, 12, and 13 according to a normal communication method.

(Ii) When some wireless devices in the group do not hold the transmission packet In the following, the case where the wireless device 12 of the group Gr1 does not hold the transmission packet will be described as an example. explain.

  FIG. 10 is a diagram illustrating another specific example of the cooperative burst continuous transmission method using the back-off time. When the transmission / reception means 22 of the wireless device 12 that does not hold the transmission packet receives a packet transmitted from another wireless device in the same group Gr1 during the cooperative burst continuous transmission mode, all the wireless devices in the group Gr1 6 and 13 perform burst transmission of packets, and set the time until the block response confirmation block ACK is received from the access point AP as NAV.

  The transmission / reception unit 22 of the wireless device 12 does not transmit a packet even if it receives a transmission packet from the communication unit 26 during the set NAV period (during the burst continuous transmission period). Moreover, the transmission / reception means 22 of the radio | wireless apparatus 12 will cancel | release NAV, if block confirmation response Block ACK is received from access point AP.

  The transmission / reception means 22 of the wireless device 7 acquires the packet transmission right as described above, and first transmits the packet PKT_7 to the access point AP.

  The transmission / reception means 22 of the wireless device 6 transmits the packet PKT_6 to the access point AP when the back-off time for one slot has elapsed since the wireless device 7 completed transmission of the packet PKT_7 to the access point AP.

  Further, the transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 to the access point AP when the back-off time for two slots has elapsed since the wireless device 6 completed transmission of the packet PKT_6 to the access point AP. The transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 when the back-off time for two slots elapses because the wireless device 6 completes the transmission of the packet PKT_6 to the access point AP and the back-off for two slots. This is because when the time elapses, the back-off time in the transmission / reception means 22 of the wireless device 13 becomes “0”.

  Thereafter, the transmission / reception means 32 of the access point AP transmits a block confirmation response Block ACK to the radio apparatuses 6, 7, 12, and 13 by the method described above.

  And the transmission / reception means 22 of the radio | wireless apparatuses 6, 7, and 13 receives block confirmation response Block ACK from access point AP, cancels | releases a burst state, and returns to cooperative burst continuous transmission mode. Further, the transmission / reception means 22 of the wireless device 12 receives the block confirmation response Block ACK from the access point AP, cancels the NAV, and returns to the cooperative burst continuous transmission mode.

  As described above, when some of the wireless devices 12 in the same group Gr1 do not hold the transmission packet, the wireless devices 6 and 13 perform time division after the wireless device 7 transmits the packet PKT_7 to the access point AP. The packets PKT_6 and PKT_13 are continuously transmitted to the access point AP.

  Therefore, it is possible to improve the throughput when transmitting packets to the access point AP while avoiding collision of the packets PKT_6 and PKT_13.

(Iii) When a transmission packet from another group is received The transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 belonging to the group Gr1 is, for example, the wireless device belonging to the group Gr2 before transmitting the packet. 8, all of the wireless devices 8 to 11 belonging to the group Gr2 transmit the packet to the access point AP by the above-described cooperative burst continuous transmission method based on the number of the wireless devices 8 to 11 belonging to the group Gr2. Until the block acknowledgment ACK ACK is received from the access point AP is set as NAV.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 stops the attempt to transmit the packet received from the communication means 26 until the NAV ends.

  After that, when the set NAV period elapses or when the block confirmation response Block ACK is received from the access point AP, the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 cancels the set NAV and cooperates. Return to burst continuous mode.

[Packet burst transmission method 2 in burst mode]
This coordinated burst continuous transmission method 2 is a method using AIFS (Arbitration Inter Frame Space).

(I) When all wireless devices in a group hold a transmission packet FIG. 11 is a diagram illustrating a specific example of a cooperative burst continuous transmission method using AIFS. In the cooperative burst continuous transmission method 2, the transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 until the first packet transmission in the group configurations Gcomp 1 to Gcomp 4 and the group Gr 1 is detected. The same operation as method 1 is performed.

  Thereafter, the transmission / reception means 22 of the wireless devices 6, 12, and 13 sets its own back-off time to “0” and sets AIFS according to the priority in the group Gr1.

  More specifically, the transmission / reception means 22 of the wireless devices 6, 12, and 13 excludes the wireless device 7 that created an opportunity to shift to the burst state among the wireless devices 6, 7, 12, and 13 in the group Gr1. The AIFS of the wireless device having the highest priority among the wireless devices 6, 12, and 13 is set to the minimum unit that can be controlled by AIFS × 1, and the AIFS of the wireless device having the second highest priority is controllable by the AIFS. In the same manner, the AIFS of each wireless device is set to the smallest unit that can be controlled by AIFS × (priority order).

  That is, among the wireless devices 6, 12, and 13, the priority is higher in the order of the wireless device 6, the wireless device 12, and the wireless device 13, and therefore when the minimum unit that can be controlled by AIFS is 5 μs, The transceiver 22 sets AIFS_6 of the wireless device 6 to 5 μs × 1 = 5 μs, and the transceiver 22 of the wireless device 12 sets AIFS_12 of the wireless device 12 to 5 μs × 2 = 10 μs. The 13 transmission / reception means 22 sets AIFS_13 of the wireless device 13 to 5 μs × 3 = 15 μs.

  Then, the transmission / reception means 22 of the wireless device 6 transmits the packet PKT_6 composed of the MAC header MH6 and the data DA6 when the AIFS_6 (minimum unit of AIFS) elapses for 5 μs after the wireless device 7 transmits the packet. Send to.

  The transmission / reception means 22 of the wireless device 12 transmits the packet PKT_12 including the MAC header MH12 and the data DA12 when 10 μs of AIFS_12 (minimum unit of AIFS × 2) has elapsed after the wireless device 6 transmits the packet PKT_6. Transmit to access point AP.

  Further, the transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 including the MAC header MH13 and the data DA13 when 15 μs of AIFS_13 (minimum unit of AIFS × 3) has elapsed after the wireless device 12 transmits the packet PKT_12. Transmit to access point AP.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 enters a state of waiting for a block response confirmation block ACK.

  The communication means 36 of the access point AP generates a block response confirmation block ACK including successful reception or unsuccessful reception of the packets PKT_7, PKT_6, PKT_12, and PKT_13, and outputs the generated block response confirmation block ACK to the transmission / reception means 32. .

  The transmission / reception means 32 of the access point AP does not detect packet transmission after detecting (a) a channel available for the longest AIFS time that can be set in the group Gr1, or (b) a radio with the lowest priority in the group Gr1. When the device packet is received, a block confirmation response Block ACK is transmitted to the wireless devices 6, 7, 12, and 13.

  More specifically, in the case of (a), when the longest AIFS is longer than SIFS, the transmission / reception means 32 of the access point AP immediately transmits a block confirmation response Block ACK to the radio devices 6, 7, 12, and 13. If the longest AIFS is equal to or less than SIFS, a block confirmation response Block ACK is transmitted to the radio apparatuses 6, 7, 12, and 13 after the SIFS has elapsed.

  Also, in the case of (b) above, the transmission / reception means 32 of the access point AP receives the packet PKT_13 from the wireless device 13 with the lowest priority in the group Gr1, and then passes the block confirmation response Block ACK when SIFS elapses. Transmit to devices 6, 7, 12, and 13.

  Then, the transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 receives the block confirmation response Block ACK from the access point AP, cancels the burst state, and returns to the cooperative burst continuous transmission mode. Thereafter, when the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 holds the transmission packet, it tries to transmit the packets PKT_ 6, PKT_ 7, PKT_ 12, PKT_ 13 to the access point AP according to the CSMA / CA scheme, respectively.

  The transmission / reception means 22 of each of the wireless devices 6, 7, 12, and 13 shifts to the burst state by the above-described method every time a packet from the wireless device of the same group Gr1 is received during the cooperative burst continuous transmission mode. Perform continuous sending.

  In the case of (a), the access point AP transmits the block confirmation response Block ACK when the wireless device 13 having the lowest priority in the group Gr1 does not hold a transmission packet or when the packet PKT_13 is wirelessly communicated. This is because the access point AP may not be reached depending on the environment or the like.

  Further, the wireless devices 6, 12, and 13 may determine their AIFS by SIFS + slot length × (priority order).

  As described above, even when AIFS is used, the wireless devices 6, 12, and 13 transmit the packets PKT_6, PKT_12, and PKT_13 continuously in time division after the wireless device 7 transmits the packet PKT_7 to the access point AP. Send to AP.

  Therefore, it is possible to improve throughput when packets are transmitted to the access point AP while avoiding collision of the packets PKT_6, PKT_12, and PKT_13.

(Ii) When some wireless devices in a group do not hold a transmission packet FIG. 12 is a diagram illustrating another specific example of the cooperative burst continuous transmission method using AIFS. When the transmission / reception means 22 of the wireless device 12 that does not hold the transmission packet receives a packet transmitted from another wireless device in the same group Gr1 during the cooperative burst continuous transmission mode, all the wireless devices in the group Gr1 6 and 13 perform burst transmission of packets, and set the time until the block response confirmation block ACK is received from the access point AP as NAV.

  The transmission / reception unit 22 of the wireless device 12 does not transmit a packet even if it receives a transmission packet from the communication unit 26 during the set NAV period (during the burst continuous transmission period). Moreover, the transmission / reception means 22 of the radio | wireless apparatus 12 will cancel | release NAV, if block confirmation response Block ACK is received from access point AP.

  The transmission / reception means 22 of the wireless device 7 acquires the packet transmission right as described above, and first transmits the packet PKT_7 to the access point AP.

  The transmission / reception means 22 of the wireless device 6 transmits the packet PKT_6 to the access point AP when 5 μs of AIFS has elapsed since the wireless device 7 completed transmission of the packet PKT_7 to the access point AP.

  Further, the transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 to the access point AP when 15 μs of AIFS has elapsed since the wireless device 6 completed transmission of the packet PKT_6 to the access point AP. The transmission / reception means 22 of the wireless device 13 transmits the packet PKT_13 when 15 μs of AIFS has elapsed. When 15 μs of AIFS has elapsed since the wireless device 6 completed transmission of the packet PKT_6 to the access point AP, the packet PKT_13 is transmitted. This is because the back-off time in the transmission / reception means 22 of the wireless device 13 is set to “0”.

  Thereafter, the transmission / reception means 32 of the access point AP transmits a block confirmation response Block ACK to the radio apparatuses 6, 7, 12, and 13 by the method described above.

  And the transmission / reception means 22 of the radio | wireless apparatuses 6, 7, and 13 receives block confirmation response Block ACK from access point AP, cancels | releases a burst state, and returns to cooperative burst continuous transmission mode. Further, the transmission / reception means 22 of the wireless device 12 receives the block confirmation response Block ACK from the access point AP, cancels the NAV, and returns to the cooperative burst continuous transmission mode.

  As described above, when some of the wireless devices 12 in the same group Gr1 do not hold the transmission packet, the wireless devices 6 and 13 perform time division after the wireless device 7 transmits the packet PKT_7 to the access point AP. The packets PKT_6 and PKT_13 are continuously transmitted to the access point AP.

  Therefore, it is possible to improve the throughput when transmitting packets to the access point AP while avoiding collision of the packets PKT_6 and PKT_13.

(Iii) When a transmission packet from another group is received The transmission / reception means 22 of the wireless devices 6, 7, 12, and 13 belonging to the group Gr1 performs "(iii) From other group in the cooperative burst continuous transmission method 1" described above. The same operation is performed as in the case of receiving a transmission packet.

[Packet burst transmission method 3 in burst mode]
This cooperative burst continuous transmission method 3 is a method that does not use a block acknowledgment block ACK.

(I) When all wireless devices in a group hold a transmission packet FIG. 13 is a diagram illustrating a specific example of a cooperative burst continuous transmission method that does not use a block acknowledgment block ACK.

  As described above, the transmission / reception means 22 of the wireless device 7 first transmits the packet PKT_7 to the access point AP in the group Gr1.

  When the transmission / reception means 22 of the wireless devices 6, 12, 13 receives the packet PKT_7 from the wireless device 7, the transmission / reception means 22 shifts to the cooperative burst continuous transmission mode. In the method using the AIFS, the back-off time is set by the method 1 and AIFS_6, AIFS_12, and AIFS_13 are set by the method in the cooperative burst continuous transmission method 2 described above.

  Further, the transmission / reception means 22 of the wireless devices 6, 12, 13 sets the NAV until an acknowledgment ACK for the transmission of the packet PKT_7 is received from the access point AP.

  When the transmission / reception unit 32 of the access point AP receives the packet PKT_7 from the wireless device 7, the transmission / reception unit 32 outputs the received packet PKT_7 to the communication unit 36 via the communication control unit 33 and receives an acknowledgment ACK from the communication unit 36.

  Then, the transmission / reception means 32 of the access point AP transmits an acknowledgment ACK to the wireless devices 6, 7, 12, 13 when SIFS has elapsed after reception of the packet PKT_7.

  The transmission / reception means 22 of the wireless device 7 receives the confirmation response ACK from the access point AP, and outputs the received confirmation response ACK to the communication means 26 via the communication control means 25.

  Further, the transmission / reception means 22 of the wireless devices 6, 12, 13 receives the confirmation response ACK from the access point AP, and cancels the NAV in response to the reception of the confirmation response ACK. Then, the transmission / reception means 22 of the wireless device 6 having the highest priority among the wireless devices 6, 12, and 13 transmits the packet PKT_6 to the access point AP when the standby time has elapsed after receiving the acknowledgment ACK.

  Note that this standby time is composed of one slot in the system using the back-off time, and is composed of the minimum unit that can be controlled by the AIFS in the system using the AIFS.

  When receiving the packet PKT_6 from the wireless device 6, the transmission / reception means 22 of the wireless devices 7, 12, 13 sets the NAV until an acknowledgment ACK for the packet PKT_6 is received from the access point AP.

  Then, after receiving the packet PKT_6, the access point AP transmits an acknowledgment ACK to the wireless devices 6, 7, 12, and 13 by the method described above.

  The transmission / reception means 22 of the wireless device 6 outputs the confirmation response ACK received from the access point AP to the communication means 26 via the communication control means 25. Moreover, the transmission / reception means 22 of the radio | wireless apparatuses 7, 12, and 13 will cancel NAV, if the confirmation response ACK is received from access point AP.

  Thereafter, the above-described operation is repeatedly executed, and the wireless devices 12 and 13 transmit packets PKT_12 and PKT_13 to the access point AP in the order of the wireless device 12 and the wireless device 13.

(Ii) When some wireless devices in the group do not hold a transmission packet In this case, the wireless devices 6, 7, 12, and 13 belonging to the group Gr1 use the above-described cooperative burst continuous transmission method 1 or cooperative burst continuous method. The same operation as “when (ii) some wireless devices in the group do not hold transmission packets” in the transmission method 2 is performed.

(Iii) When a transmission packet from another group is received In this case, the transmission / reception means 22 of the wireless devices 6, 7, 12, 13 belonging to the group Gr1 uses “(iii) Others in the cooperative burst continuous transmission method 1 described above. The same operation as “when a transmission packet is received from the other group” is performed.

  Note that the wireless devices 8 to 11 belonging to the group Gr2 shown in FIG. 8, the wireless devices 1, 5, 14, and 15 belonging to the group Gr3, and the wireless devices 2 to 4 and 16 belonging to the group Gr4 are also used in the above-described cooperative burst continuous transmission. The packet is transmitted to the access point AP in the burst mode using any one of the method 1 to the cooperative burst continuous transmission method 3.

  FIG. 14 is a flowchart for explaining the operation of a wireless device having a transmission packet in the burst mode.

  Referring to FIG. 14, when a series of operations is started, each wireless device 1-16 determines whether or not a burst mode transition notification has been received from access point AP (step S1). And each radio | wireless apparatus 1-16 will access a channel according to CSMA / CA, if the notification of burst mode transfer is received from access point AP (step S2).

  Thereafter, each of the wireless devices 1 to 16 determines whether or not the right to transmit a packet has been acquired (step S3).

  When it is determined in step S3 that the packet transmission right has been acquired, each of the wireless devices 1 to 16 shifts to a burst state (step S4) and transmits the packet to the access point AP (step S5). And each radio | wireless apparatus 1-16 will be in the waiting state of block confirmation response Block ACK (step S6).

  Thereafter, each of the wireless devices 1 to 16 determines whether or not a block confirmation response Block ACK has been received (step S7).

  If it is determined in step S7 that the block confirmation response Block ACK has been received, the wireless devices 1 to 16 cancel the burst state (step S8).

  On the other hand, when it is determined in step S7 that the block acknowledgment block ACK has not been received, each of the wireless devices 1 to 16 cancels the burst state and prepares to retransmit the packet (step S9).

  On the other hand, when it is determined in step S3 that the transmission right has not been acquired, each of the wireless devices 1 to 16 receives a packet from another wireless device (step S10). And each radio | wireless apparatus 1-16 determines whether another radio | wireless apparatus belongs to the same group as self (step S11).

  When it is determined in step S11 that the other wireless devices belong to the same group as the self, each of the wireless devices 1 to 16 shifts to the burst state and sets the back-off time or the IFS value according to the priority (step S11). S12).

  Each wireless device 1-16 transmits a packet according to the set back-off time or IFS (step S13), and enters a block confirmation response block ACK waiting state (step S14).

  Thereafter, each of the wireless devices 1 to 16 determines whether or not a block confirmation response Block ACK has been received (step S15).

  If it is determined in step S15 that the block confirmation response Block ACK has been received, the wireless devices 1 to 16 cancel the burst state (step S16).

  On the other hand, when it is determined in step S15 that the block acknowledgment block ACK has not been received, each of the wireless devices 1 to 16 cancels the burst state and prepares to retransmit the packet (step S17).

  On the other hand, when it is determined in step S11 that the other wireless devices do not belong to the same group as the self, each of the wireless devices 1 to 16 has a NAV corresponding to the number of all the wireless devices in the group to which the other wireless devices belong. Is set (step S18).

  Thereafter, the NAV times out or receives a block acknowledgment Block ACK (step S19), and the series of operations returns to step S2.

  Then, after any of step S8, step S9, step S16, and step S17, a series of operations ends.

  As described above, when the wireless devices 1 to 16 holding the packet to be transmitted to the access point AP receive the burst mode transition notification from the access point AP and acquire the packet transmission right, the wireless apparatuses 1 to 16 transition to the burst state. Then, the packet is transmitted to the access point AP (see step S3 to step S5).

  When a wireless device belonging to the same group other than the wireless device that first transmitted the packet to the access point AP receives a packet from the wireless device that first transmitted the packet to the access point AP, the wireless device shifts to the burst state and The packets are transmitted to the access point AP at different timings according to the priority order (see step S10 to step S13).

  As a result, wireless devices belonging to the same group continuously transmit packets to the access point AP in time division.

  Therefore, throughput can be improved while avoiding packet collision.

  FIG. 15 is a flowchart for explaining the operation of the wireless device having no transmission packet in the burst mode.

  Referring to FIG. 15, when a series of operations is started, each wireless device 1-16 receives a packet from another wireless device (step S21), and the group size of the group to which it belongs (wireless belonging to the group). NAV is set according to the number of devices) (step S22).

  And each radio | wireless apparatus 1-16 determines whether the block confirmation response Block ACK was received from access point AP (step S23).

  When it is determined in step S23 that the block confirmation response Block ACK has been received, each of the wireless devices 1 to 16 cancels the NAV (step S24).

  On the other hand, when it is determined in step S23 that the block confirmation response Block ACK has not been received, the NAV times out as time elapses (step S25).

  And a series of operation | movement is complete | finished after step S24 or step S25.

  In this way, wireless devices that do not hold transmission packets enter a standby state until all other wireless devices that belong to the same group as the wireless device have finished transmitting packets. There is no hindrance to sending.

  FIG. 16 is a flowchart for explaining the operation of the access point. Referring to FIG. 16, when a series of operations is started, access point AP has a throughput when the number N of wireless devices accessing itself is larger than threshold value Nth and packets are transmitted to itself. The necessity of coordinated burst continuous transmission is detected by detecting that THP is smaller than threshold value THPth (step S31).

  Then, the access point AP performs grouping of the wireless devices 1 to 16 by the method described above (step S32).

  Thereafter, the access point AP transmits a burst mode transition notification to the wireless devices 1 to 16, and notifies the wireless devices 1 to 16 of the group configuration (step S33).

  Then, cooperative burst continuous transmission is executed (step S34). After that, the access point AP determines whether or not the cooperative burst continuous transmission release notification is necessary (step S35).

  When it is determined in step S35 that the notification of cooperative burst continuous transmission cancellation is not necessary, the series of operations returns to step S34.

  On the other hand, when it is determined in step S35 that the cooperative burst continuous transmission cancellation notification is necessary, the access point AP transmits a burst mode cancellation notification to the wireless devices 1 to 16, and cancels the cooperative burst continuous transmission mode. The wireless devices 1 to 16 are instructed (step S36).

  Thereby, each radio | wireless apparatus 1-16 cancel | releases cooperation burst continuous transmission mode, and transfers to normal mode.

  And a series of operation | movement is complete | finished after step S36.

  As described above, when the access point AP detects the necessity for the cooperative burst continuous transmission, the wireless devices 1 to 16 are instructed to shift to the cooperative burst continuous transmission mode, so that a plurality of wireless devices perform the cooperative burst continuous transmission. be able to.

  In the above description, it has been described that the table creating means 23 of each of the wireless devices 1 to 16 calculates the average value RSSI_AVE of the received signal strength RSSI for several seconds to create the signal reception table 24. In this case, the average value RSSI_AVE is calculated. You may calculate by a moving average.

  In the above description, it has been described that the signal reception table 24 stores the average value RSSI_AVE of the received signal strength RSSI between the two wireless devices. However, in the embodiment of the present invention, the signal reception table 24 is not limited thereto. 24 may store an instantaneous value of the received signal strength RSSI between the two wireless devices, or may store a packet loss rate between the two wireless devices, and in general, between the two wireless devices. The wireless communication quality may be stored.

  When the signal reception table 24 stores the instantaneous value of the received signal strength RSSI between the two wireless devices, the reception status table 35 also stores the instantaneous value of the received signal strength RSSI between the two wireless devices. When 24 stores the packet loss rate between the two wireless devices, the reception status table 35 also stores the packet loss rate between the two wireless devices, and the signal reception table 24 stores the wireless communication quality between the two wireless devices. In this case, the reception status table 35 also stores the wireless communication quality between the two wireless devices.

  The communication control means 33 of the access point AP refers to the reception status table 35 and determines whether to divide the wireless devices 1 to 16 into groups by the method described above. Therefore, generally, the communication control means 33 of the access point AP determines whether to divide the wireless devices 1 to 16 into groups by the method described above based on the wireless communication quality between the two wireless devices.

  Furthermore, in the above description, each of the wireless devices 1 to 16 has been described as transmitting the signal reception table 24 to the access point AP periodically (period Treport). However, the embodiment of the present invention is not limited thereto. Each of the wireless devices 1 to 16 may transmit the signal reception table 24 to the access point AP when a new wireless device is added to the signal reception table 24 held by itself.

  In other words, in the wireless communication system 100 shown in FIG. 1, it is assumed that a new wireless device 17 is generated and the wireless device 1 detects packet transmission from the wireless device 17 to the access point AP. In this case, since the wireless device 1 adds the wireless device 17 as a new entry to the signal reception table 24-2 (see FIG. 6C), the signal reception table 24 is accessed using the addition of the new entry as a trigger. Send to point AP.

  Further, when it is determined that the access point AP shifts to the cooperative burst continuous transmission mode, a transmission request of the signal reception table 24 is inserted into the beacon frame Bcon, and each of the wireless devices 1 to 16 is included in the signal reception table 24 included in the beacon frame Bcon. The signal reception table 24 may be transmitted to the access point AP in response to the transmission request.

  Furthermore, in the above description, the access point AP transmits a packet to the wireless devices 1 to 16 by a normal communication method. However, in the embodiment of the present invention, the access point AP is not limited to this. The packet may be transmitted to the wireless devices 1 to 16 in the mode.

  Further, in the above description, the wireless communication system 100 has been described as including the access point AP and the wireless devices 1 to 16 that perform wireless communication with the access point AP. However, in the embodiment of the present invention, However, the wireless communication system 100 may include an ad hoc network in which a plurality of wireless devices autonomously form a network.

  In this case, one wireless device on the reception side performs the function of the access point AP described above, and a plurality of wireless devices on the transmission side perform the functions of the wireless devices 1 to 16 described above. Therefore, in the ad hoc network, when a plurality of wireless devices transmit a packet to one wireless device, the above-described cooperative burst continuous transmission can be applied.

  In the embodiment of the present invention, the access point AP constitutes a “first wireless device”.

  In the embodiment of the present invention, the wireless devices 1 to 16 constitute “a plurality of second wireless devices”.

  Further, in the embodiment of the present invention, the threshold value THPth constitutes a “first threshold value”, and the threshold value Nth constitutes a “second threshold value”.

  Furthermore, in the embodiment of the present invention, the wireless devices 6, 7, 12, and 13 constitute “n (n is an integer of 2 or more) second wireless devices”, and the wireless device 12 i (i is a positive integer) number of second wireless devices ", and the wireless devices 6 and 13 constitute" ni second wireless devices ".

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless communication system capable of improving throughput while avoiding a collision.

  1 to 16 wireless device, 21 and 31 antenna, 22 and 32 transmission / reception means, 23 and 34 table creation means, 24 signal reception table, 25 and 33 communication control means, 26 and 36 communication means, 35 reception status table, 100 wireless communication System, AP access point.

Claims (9)

A plurality of wireless devices determine whether or not to shift to a burst mode in which packets are continuously transmitted in time division, and when determined to shift to the burst mode, a burst mode shift notification is transmitted and the burst mode is A first wireless device that receives the packet;
A plurality of second wireless devices that continuously transmit packets to the first wireless device in time division in response to receiving a burst mode transition notification from the first wireless device ;
The first wireless device shifts to the burst mode when the throughput of wireless communication is smaller than a first threshold and the number of the second wireless devices that access the first wireless device is larger than a second threshold. A wireless communication system that determines to do so . The first wireless device is configured such that when the throughput is greater than or equal to the first threshold, or when the number of the second wireless devices accessing itself is less than or equal to the second threshold, or the throughput is greater than or equal to the first threshold. When the number of the second radio apparatuses accessing the self is equal to or greater than the first threshold and less than or equal to the second threshold, a burst mode release notification for notifying the release of the burst mode is sent to the plurality of second radio devices. To the two wireless devices,
Wherein each of the plurality of second wireless device releases the burst mode in response to the burst mode cancellation notification, the wireless communication system according to claim 1. The first wireless device determines whether to divide the plurality of second wireless devices into groups based on wireless communication quality between the plurality of second wireless devices, and the plurality of second wireless devices. The wireless devices can be detected and decoded between the second wireless devices belonging to the same group based on the wireless communication quality among the plurality of second wireless devices. Dividing the plurality of second wireless devices into groups, and transmitting the grouping result together with the burst mode transition notification to the plurality of second wireless devices,
Each of the plurality of second wireless devices receives the burst mode transition notification and the result of grouping, and continues the packets in time division in cooperation with other second wireless devices belonging to the same group. The wireless communication system according to claim 1, wherein the wireless communication system transmits to the first wireless device. When the first radio apparatus determines that the plurality of second radio apparatuses cannot be divided into groups, a burst mode release notification instructing the release of the burst mode is sent to the plurality of second radio apparatuses. Send
4. The wireless communication system according to claim 3 , wherein each of the plurality of second wireless devices releases the burst mode in response to the burst mode release notification. When the first wireless device determines to divide the plurality of second wireless devices into groups, the number of second wireless devices belonging to each group is equal to or less than an allowable value. In addition, the group is divided into as few groups as possible, and the priority order in which each second wireless device transmits a packet is determined in each group, and the grouped group name and each group are determined. Transmitting the identifier of the second wireless device to which it belongs and the priority of each second wireless device in each group together with the burst mode transition notification to the plurality of second wireless devices;
Each of the plurality of second wireless devices includes the burst mode transition notification, the name of the group, the identifier of the second wireless device belonging to each group, and the priority of each second wireless device in each group. When receiving and detecting that another second wireless device belonging to the same group as itself has transmitted the packet to the first wireless device, the packet is transmitted to the first wireless device according to its own priority. The wireless communication system according to claim 3 , wherein the transmission is performed. When n (n is an integer of 2 or more) second wireless devices belonging to the same group hold all the n second wireless devices hold packets to be transmitted to the first wireless device. The packets are transmitted to the first radio apparatus in order of priority, and i (i is a positive integer) second radio apparatuses out of the n second radio apparatuses. When the packet to be transmitted to one wireless device is not held, the packet is transmitted to the first wireless device according to the priority order of the remaining second wireless devices excluding the i second wireless devices. The wireless communication system according to claim 5 . The wireless communication system according to claim 6 , wherein the i second wireless devices wait until all of the ni second wireless devices transmit the packet to the first wireless device. When each of n (n is an integer of 2 or more) second wireless devices belonging to the same group receives a packet transmitted by the second wireless device belonging to another group to the first wireless device, The wireless communication system according to claim 5 , wherein all the second wireless devices belonging to the other group wait until they transmit the packet to the first wireless device.   2. When the first wireless device receives the packet in the burst mode, the first wireless device transmits an acknowledgment indicating that the packet has been received to the second wireless device that has transmitted the packet in the burst mode. The wireless communication system according to 1.

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