JP2009044200A - Wireless communication method and wireless communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a spatial band reuse rate of data transmission slots in TDMA communication of an ad hoc network. <P>SOLUTION: A reservation passive side informs a reservation actuation side of a reservation state of its circumference with a slot busy flag so that a unidirectional communication slot reservation can be made in addition to a bidirectional communication slot reservation made through normal TDMA communication, and then the reservation actuation side integrates the reservation state with a reservation state of its circumference to make a slot reservation under conditions more relaxed than those of the bidirectional communication. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to communication networks, and particularly to ad hoc network communication in wireless communication networks.

  As a conventional wireless communication method, there is a wireless communication method described in Non-Patent Document 1. This can be said to be a kind of wireless network protocol of the TDMA system in WPAN (more precisely, a hybrid system with CSMA / CA).

  According to the wireless communication method of Non-Patent Document 1, a PNC (piconet controller) which is a control station receives a request from a wireless communication device (DEV) under its control and performs channel time allocation (CTA) in a channel time allocation period (CTAP). ). Each DEV exchanges user data in accordance with the allocated time. The configuration of the IEEE 802.15.3 MAC superframe is shown in FIG.

  Also, as disclosed in Non-Patent Document 2, a similar TDMA slot allocation method in an autonomous distributed network is considered.

  FIG. 9 is a diagram showing the structure of a super frame.

  In FIG. 9, the super frame is divided into a beacon period 901 and a data period 902.

  The beacon 903 is transmitted from each wireless communication device within the beacon period 901, but the beacon of the neighboring node is guaranteed to be transmitted to the neighboring node without colliding.

  The data periods 902 are equally divided and slot IDs are assigned in that order. However, the present invention is not limited to this, and the data periods need not be equal and need not be adjacent.

  FIG. 10 is a diagram showing an arrangement of wireless communication devices in an autonomous distributed network, and each of the wireless communication devices 1001 to 1004 performs wireless communication with wireless communication devices in the communicable areas 1101 to 1104. In starting this wireless communication, each of the wireless communication devices 1001 to 1004 participating in the autonomous distributed network transmits a beacon and declares a slot to be occupied in the data period of the superframe shown in FIG. To do. If there is a slot that has already been declared at the source and destination where communication is declared, each node cooperates so that the priority is weighted and the slot is assigned to the communication with high importance. Then, lower-priority communication is withdrawn.

In this case, in the communication in the slot, a frame is transmitted from the initiator side (wireless communication apparatus A) to the passive person side (wireless communication apparatus B) or from the passive person side (wireless communication apparatus B) to the initiator side (wireless It is also possible to transmit a frame to the communication device A). Thereby, the person who reserved the slot (wireless communication apparatus A) can request the receiver (wireless communication apparatus B) for ACK for arrival confirmation, and the receiver (wireless communication apparatus B). When the frame is normally received, ACK is returned in the same slot.
IEEE 802.15.3 “Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for High Rates Wireless Personal Area Networks (WPANs)” “Towards High Speed Wireless Personal Area Network-Efficiency Analysis of MBOA MAC” Yunpeng Zang, etc Internet URL: http://www.ctr.kcl.ac.uk/IWWAN2005/papers/88_invited_Philips.pdf

  However, in the conventional wireless communication method, when the wireless communication device A (1001) communicates with the wireless communication device B (1002), the wireless communication device C (1003) in the communicable area of the wireless communication device B (1002) is used. Communication with the wireless communication device D (1004) in the same slot is not allowed. This is because when the wireless communication device C (1003) is transmitting, the wireless signal from the wireless communication device A (1001) is in an interference state by the wireless signal, and the wireless communication device B (1002) is connected to the wireless communication device A (100 This is because the wireless signal from 1001) cannot be received correctly. Similarly, since there is a possibility of interference when the wireless communication device C (1003) receives, the wireless communication devices A and B use the wireless communication device C (1003) and the wireless communication device D (1004). Communication is not possible in the same slot.

  As described above, when the wireless communication device reserves the TDMA slot as bidirectional communication, the other wireless communication devices located within the communicable area of the wireless communication device can transmit other wireless devices in a positional relationship that allows transmission. Communication is not possible in the same slot as the communication device, and there is a problem that communication band reuse efficiency is reduced.

  The wireless communication method of the present invention is a wireless communication method for realizing time division communication in an ad hoc network, in which a wireless communication device designates a specific data transmission slot and performs unidirectional transmission, unidirectional reception, or bidirectional communication. A step of reserving use in another wireless communication device, a step in which the wireless communication device manages a reservation state reserved from another wireless communication device, and a data transmission slot based on the reservation state. Generates slot information indicating whether or not transmission or reception is possible and notifies the other wireless communication device, and when the wireless communication device performs unidirectional transmission or unidirectional reception, manages itself Determining a data transmission slot to be used from the reservation status to be performed and the slot information notified from the wireless communication device of the communication partner. It is.

  As a result, the start-side wireless communication device of the unidirectional communication can grasp the communication status in the data communication slots of the self-passive wireless communication device and the start-side wireless communication device more densely and spatially retransmits the bandwidth. Available slots can be determined.

  Further, the step of determining the data transmission slot of the wireless communication method of the present invention includes a step in which the wireless communication device is a wireless communication device that is performing bidirectional communication based on the reservation status, or a wireless communication device that is not the receiving side. A step of detecting a transmission slot; a step of detecting a data transmission slot from which the wireless communication device of the communication partner is not transmitting / receiving from the slot information and the wireless communication device in the communicable area of the communication partner is not transmitting; And determining the data transmission slot detected in common in both steps as a data transmission slot to be used for communication.

  Thereby, the start side communication apparatus of the unidirectional communication can select the data communication slot which can perform the maximum communication.

In the wireless communication method of the present invention, the communication partner wireless communication device receives a reservation from the communication request source wireless communication device, and determines whether the communication partner wireless communication device can communicate. And the step of reserving the same data transmission slot to the wireless communication device that is the communication request source.

  As a result, the wireless communication device designated as the communication partner can notify the communication requesting wireless communication device that the slot reservation has been accepted, so that the wireless communication devices performing unidirectional communication mutually confirm each other. , Communication can begin.

  Further, the time division communication in the wireless communication method of the present invention is performed in a superframe period composed of a beacon period for transmitting a beacon and a data period for transmitting data, and the reservation of the data transmission slot and the slot information are the beacon. To be notified.

  Thus, the wireless communication device can reserve a data transmission slot by using a beacon.

  The wireless communication method of the present invention also confirms arrival by a beacon in the next superframe when the wireless communication device of the communication partner normally receives data reserved for unidirectional transmission from the wireless communication device of the communication request source. A step of notifying information.

  Thereby, the wireless communication apparatus can confirm normal reception of data even in unidirectional communication.

  The wireless communication apparatus of the present invention constitutes a wireless network that realizes time division communication in an ad hoc network. Then, the wireless communication device of the present invention designates a data transmission slot, and informs a neighboring node that it is a transmitter / receiver of bidirectional communication, a sender or receiver of unidirectional communication in the data transmission slot. Communication direction indication means for notification, busy slot indication means for notifying neighboring nodes whether transmission or reception is possible in each data transmission slot, and communication notified from communication direction indication means of other wireless communication devices From the slot information receiving means for receiving the direction information and the slot busy information notified from the busy slot specifying means, and the communication direction information and the slot busy information received by the slot information receiving means when performing unidirectional communication, Slot determining means for determining a data transmission slot to be used by itself.

  As a result, the wireless communication device can grasp the communication status in the data communication slot of the wireless communication device itself and the passive wireless communication device when it is the start side of the unidirectional communication, so that the spatial reuse of the band can be performed more densely. Slots can be determined.

  Further, the slot determination means of the wireless communication device of the present invention detects a data transmission slot in which there is no wireless communication device performing bidirectional communication and no wireless communication device on the receiving side from the communication direction information. Further, the slot determining means is not transmitting / receiving the communication partner's wireless communication device from the slot busy information of the communication partner's wireless communication device, and is not transmitting by the communication partner's communicable area. Detect the data transmission slot. Then, the data transmission slot detected in common in both is determined as the data transmission slot used for communication.

  As a result, the wireless communication device can select a data communication slot that allows maximum communication when the wireless communication device is the unidirectional communication starter.

  In addition, the wireless communication device of the present invention has a communication availability determining unit that determines whether communication is possible when the slot information receiving unit receives a communication request from another wireless communication device, and the communication availability determining unit can communicate. Is determined, the communication direction indication means is instructed to notify the communication request source wireless communication apparatus of its own communication direction in the same data transmission slot.

  Further, the time division communication performed by the wireless communication apparatus of the present invention is performed in a superframe cycle composed of a beacon period for transmitting a beacon and a data period for transmitting data. The wireless communication device includes a data receiving unit that receives a data frame transmitted in one direction in the data transmission slot, a data reception determining unit that determines whether or not the data frame is normally received, and the data reception determination And the beacon transmitting means for transmitting the information including the arrival confirmation information at the time of beacon transmission in the super frame circulation or the next circulation.

  Thereby, the wireless communication apparatus can confirm normal reception of data even in unidirectional communication.

  When the wireless communication apparatus reserves a TDMA slot and communicates with another wireless communication apparatus located in the communicable area, the communication band reuse efficiency is improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a configuration diagram of the wireless communication apparatus according to the present embodiment.

  In FIG. 2, the radio processing unit 201 demodulates a signal received from the antenna 200 and then digitally converts it to generate a frame, or analog-converts the frame and then modulates and transmits it from the antenna 200. The antenna 200 is an omnidirectional antenna and emits radio waves into a communicable area. The wireless processing unit 201 has the functions of a data receiving unit and a beacon transmitting unit according to the present invention.

  The frame determination unit 202 determines a frame from the wireless processing unit 201, determines a normal frame to the higher layer processing unit 204, a beacon to the beacon reception processing unit 205, and an ACK (acknowledge) frame to the ACK / retransmission processing unit 203. To send. At this time, it is also notified that the frame has been normally received. However, when the wireless communication apparatus is performing two-way communication, if the frame requires an ACK response, the ACK / retransmission processing unit 203 requests ACK transmission at the same time as sending the frame to the higher layer processing unit 204. To do. Also, the frame determination unit 202 extracts a frame ID that is a sequence number of the frame given to the data frame, and notifies the beacon reception processing unit 205 of it. The frame determination unit 202 has the function of a data reception determination unit according to the present invention.

  Here, the structure of the beacon frame is shown in FIG.

  In FIG. 3, the beacon in the present embodiment has slot reservation information 301, a slot busy flag 302, and an ACK list 303 in an option field.

  The slot reservation information 311 reserves a slot in order to transmit or receive data with a data period, and includes a counterpart DEV 311, a communication direction 312, a priority 313, a reserved communication slot 314, and a beacon ACK 315. The partner DEV 311 is an identifier that identifies the wireless communication device of the communication partner, and the communication direction 312 indicates whether it is a unidirectional communication transmitter, receiver, or bidirectional communication. is there. In this embodiment, it is “01” when the receiving side is “10” when it is the transmitting side, and “11” when it is bidirectional.

  The priority 313 indicates the priority of communication performed by itself, and each wireless communication device autonomously determines so as to give priority to the communication with the higher priority in the same slot. The reserved communication slot 314 specifies a slot that it intends to reserve, and all slots in the data period can be specified by a bitmap. The beacon ACK 315 indicates whether or not to request a beacon ACK from the receiving side. This beacon ACK is a request for receiving an ACK notification from a receiver not by a data slot but by a beacon.

  When the receiving wireless communication apparatus designated as the communication partner receives the request for the slot reservation information 311 and transmits a beacon with the slot reservation information 311 in which the transmitting wireless communication apparatus is set to the partner DEV 311, the slot reservation information is received. Is completed. Further, the communication partner may designate a plurality of partners as in multicast. In this case, unidirectional communication is performed, but the slot reservation information 301 is provided by the number of partner communication.

  In the slot busy flag 302, the usage status of each data slot is set in the order of each data slot ID by 2 bits per slot. Specifically, “00” is set when there is no wireless communication device that is not transmitting / receiving itself and is also transmitting / receiving to / from its surroundings. Is set to “01” when there is only a wireless communication device on the receiving side. Furthermore, “11” is set when the device is transmitting / receiving or there is at least one wireless communication device that is transmitting around the device. In addition, “10” is set when there is only a transmitting wireless communication device around itself.

  The ACK list 303 is for the receiver to send an ACK notification to the sender using a beacon. The ACK list 303 includes an ACK list ID 331, a slot number 332, a slot ID 333, and an ACK bitmap 334. As many slot IDs 333 and ACK bitmaps 334 as the number of slot objects requested for beacon ACK are provided (335).

  The ACK list ID 331 is an identifier indicating that the subsequent data is an ACK list, and the slot number 332 indicates the number of pairs of the slot ID 333 and the ACK bitmap 334 that follow. The slot ID 333 indicates a target slot ID to which an ACK is responded, and the ACK bitmap 334 indicates a frame to which an ACK is to be responded. When a frame ID is 'k', an ACK response is given. '1' is set to the kth bit from the beginning.

  When the beacon reception processing unit 205 receives the beacon frame from another wireless communication device, the beacon reception processing unit 205 records the slot reservation table shown in FIG. 4A in the recording unit 206 based on the slot reservation information 301. This slot reservation table corresponds to the reservation status according to the present invention.

  4A, the DEV_ID 401, the communication direction 402, the priority 403, the reserved communication slot 404, and the beacon ACK 405 include the counterpart DEV 311, the communication direction 312, the priority 313, the reserved communication slot 314, the slot reservation information 301, respectively. And a beacon ACK 315 is recorded.

  Also, the beacon reception processing unit 205 extracts the slot busy flag from the beacon frame and records it in the recording unit 206 as a wireless communication device surrounding state table shown in FIG. In this wireless communication device surrounding state table, a busy flag (busy state 412) of each slot ID 411 is recorded for each wireless communication device that is a beacon transmission source.

  In addition, beacon reception processing section 205 extracts ACK list 303 from the beacon frame and sends it to ACK / retransmission processing section 203. Further, the beacon reception processing unit 205 records the frame ID notified from the frame determination unit 202 in the recording unit 206. Then, when the ACK list 303 is transmitted to the ACK / retransmission processing unit 203, the latest frame ID is also transmitted. The beacon reception processing unit 205 corresponds to the slot information receiving unit according to the present invention.

  The upper layer processing unit 204 executes various applications, generates transmission data such as content data, and transmits the transmission data to the frame configuration unit 207 or requests slot reservation from the beacon generation unit 205.

  The beacon generation unit 205 further includes a communication availability determination unit 212, a communication direction specification unit 213, a busy slot specification unit 214, a slot determination unit 215, and an ACK list generation unit 216.

  When receiving a communication request from the upper layer processing unit 204, the communication direction indicating unit 213 performs setting according to the request in the slot reservation information 301. At this time, the slot determination unit 215 determines a slot to be used for communication.

  Based on the slot reservation table recorded in the recording unit 206, the busy slot specifying unit 214 sets the usage state indicated by “00” to “11” in the slot busy flag 302 of the corresponding slot number. This corresponds to slot information according to the present invention.

  The ACK list generation unit 216 is recorded in the recording unit 206 when it is notified by the frame determination unit 202 that data reception has been successful when it is a receiver and a beacon ACK is requested. An ACK list 303 is generated in which ACK ('1') is set at the position of the current frame ID.

  When the counterpart DEV 311 of the slot reservation information 301 is its own DEV_ID, the communication availability determination unit 212 inquires of the higher layer processing unit 204 or refers to the slot reservation table to determine whether communication is possible.

  The ACK / retransmission processing unit 203 receives normal ACK frames and performs beacon ACK reception processing. In particular, in the beacon ACK reception processing, the ACK / retransmission processing unit 203 analyzes the ACK list 303 received from the beacon reception processing unit 205, and whether the ACK bit for the transmitted data is set at the notified frame ID position. Determine whether or not. If the ACK bit is not set, the frame configuration unit 207 is instructed to retransmit.

  The frame configuration unit 207 generates a data frame by adding a header, or generates a normal ACK frame or beacon frame by bidirectional communication, and transmits the frame to the wireless processing unit 201. At this time, the frame configuration unit 207 assigns a frame ID. Further, the frame configuration unit 207 stores a copy of the frame in the retransmission frame buffer unit 208 when sending it to the wireless processing unit 201.

Further, when the frame construction unit 207 is instructed to retransmit the frame from the ACK / retransmission processing unit 203, the frame configuration unit 207 reads the frame transmitted in the previous superframe cycle from the retransmission frame buffer unit 208. Then, the data is sent to the wireless processing unit 201 for retransmission.
Moreover, the operation | movement and effect | action are demonstrated below about the radio | wireless communication apparatus comprised as mentioned above.

  First, a beacon receiving operation that is always performed by the wireless communication device will be described.

  First, the radio processing unit 201 extracts a frame from the radio wave received by the antenna 200 and sends the frame to the frame determination unit 202.

  If the received frame is a beacon frame, the frame determination unit 202 sends it to the beacon reception processing unit 205.

  If there is slot reservation information 301 in the option field of the beacon frame, beacon reception processing section 205 generates a slot reservation table based on the information and records it in recording section 206. At this time, if the information of the same wireless communication device is recorded in the slot reservation table, it is updated with new information.

  If the partner DEV 311 of the slot reservation information 301 describes its own DEV_ID, the beacon reception processing unit 205 determines that the request is a communication request to itself, and the received slot reservation information and beacon source wireless communication The DEV_ID of the device is recorded in the recording unit 206 as communication reservation information.

  Next, the beacon reception processing unit 205 generates a wireless communication device surrounding state table based on the slot busy flag 302 of the beacon frame and records it in the recording unit 206. The beacon reception processing unit 205 updates this information for each super frame.

  Thereafter, the reception process is terminated, and a transition is made to a reception standby state.

  When the above beacon receiving operation is completed for one super cycle, the slot reservation table records the communication reservation status within its own communicable area, and the wireless communication device surrounding status table stores the latest communication partner wireless communication device. Ambient conditions are recorded.

  Next, an operation for transmitting a beacon from the wireless communication device will be described.

  First, the communication feasibility determination unit 212 checks the communication reservation information in the recording unit 206, and if the communication reservation information is recorded, it determines whether or not the reserved communication slot 314 of the slot reservation information 301 is usable. Judgment is made with reference to the reservation table.

  When there is a wireless communication device that reserves the same slot in the reserved communication slot 404, the beacon generation unit 209 transmits ("10") or bidirectional ("11") the communication direction 402 of the wireless communication device. Check whether or not. If these are recorded, it is determined that communication is impossible, and the generation of slot reservation information is stopped.

  On the other hand, when the communication direction 402 is not transmission (“10”) or bidirectional (“11”), the communication availability determination unit 212 determines that communication is possible and generates slot reservation information for which recorded slot reservation information is being generated. 301, and the partner DEV 311 is recorded as communication reservation information and rewritten to DEV_ID. Further, in the communication direction 312, “01” indicating the receiving side is set if it is requested as the receiving side, and “10” indicating the transmitting side is set if it is requested as the transmitting side. If bidirectional is requested, “11” indicating bidirectional is set.

Next, the busy slot clarification unit 214 fills in the slot busy flag 302 with the surrounding communication status based on the slot reservation table. That is, the busy slot indication part 2
14 determines a slot busy flag based on the information of the communication direction 402. For example, if the information on the communication direction 402 is bidirectional (“11”) or the transmission side (“10”), the busy flag is “11”, and the information on the communication direction 402 is on the reception side (“01”). If there is, the busy flag is “01”, and if the information of the communication direction 402 is any other value, the busy flag is set to “00”. The busy flags of slots other than the above that are not recorded in the slot reservation table are set to “00”.

  Next, the beacon generation unit 209 transmits beacon data including the generated slot reservation information 301 and the slot busy flag 302 to the frame configuration unit 207.

  After receiving this beacon data, the frame configuration unit 207 adds a beacon header to configure a beacon frame and sends it to the wireless processing unit 201.

  Then, the wireless processing unit 201 emits a beacon from the antenna 200 at a predetermined timing.

  The above is the operation when a beacon is transmitted from the wireless communication device.

  Next, an operation when data is transmitted from the wireless communication device will be described. This communication is assumed to be unidirectional communication.

  First, the upper layer processing unit 204 instructs the beacon generation unit 209 to make a slot reservation when transmitting data created by an application to another wireless communication device.

  In response to the slot reservation instruction, the slot determination unit 215 determines a data slot by the following processing and generates slot reservation information.

  FIG. 6 is a flowchart showing a slot determination method for unidirectional communication.

  In FIG. 6, first, the slot determination unit 215 refers to the reserved communication slot 404 of the slot reservation table and determines whether or not reservations are made in order from the first slot (step S601). If reserved, the slot determining unit 215 refers to the communication direction 402 corresponding to the slot and determines whether the communication direction is bidirectional communication (“11”) or the receiving side (“01”). Confirmation is made (step S602). In the case of two-way communication (“11”) or the receiving side (“01”), the reserved communication may be hindered, so that slot cannot be used. The process proceeds to step S607.

  On the other hand, when it is not the bidirectional communication (“11”) or the receiving side (“01”), and when there is no slot reservation in step S601, the slot determination unit 215 wirelessly determines the surrounding state of the wireless communication device that is the communication partner. It is obtained from the communication device surrounding situation table (step S603). When the busy state 412 of the corresponding slot number 411 is “00” or “01”, the beacon generation unit 209 has nothing to transmit / receive around the partner wireless communication device, or at least transmits the wireless communication device Therefore, the partner wireless communication apparatus determines that reception is possible, and sets the bit at the corresponding slot position in the reserved slot 314 of the slot reservation information 301 (step S604).

Further, when the busy state 412 of the corresponding slot number 411 is “10”, the beacon generation unit 209 is not communicating because the communication partner is transmitting / receiving or there is a wireless communication device transmitting in the vicinity thereof. Step S60 to check the next slot.
Move to 7.

  Next, the slot determination unit 215 checks whether or not the number of slots necessary for transmitting the transmission data has been selected (step S605), and if the number of slots is sufficient, the slot determination process ends. Then, the communication direction indication unit 213 enters the ID of the target wireless communication apparatus in the counterpart DEV 311 and enters “10” indicating the transmission side in the communication direction 312. The priority 313 and the beacon ACK 315 are set so as to satisfy the communication quality (QoS) requested from the higher layer processing unit 204 (step S606).

  On the other hand, if the number of slots is insufficient, it is determined whether or not the above steps S601 to S605 have been completed up to the final slot ID (step S607). If not completed, the process proceeds to step S601 again to determine the next slot.

  As described above, the communication direction indication unit 213 and the slot determination unit 215 generate the slot reservation information 301.

  Next, the busy slot clarification unit 214 fills the slot busy flag 302 with its surrounding communication status based on the slot reservation table. That is, the busy slot specifying unit 214 sets “11” indicating that it is transmitting at the slot position reserved by the slot reservation information, and other slot positions recorded in the reserved communication slot 404 are set. The slot busy flag is determined based on the information on the communication direction 402. For example, if the information on the communication direction 402 is bidirectional (“11”) or the transmission side (“10”), the busy flag is “11”, and the information on the communication direction 402 is on the reception side (“01”). If there is, the busy flag is “01”, and if the information of the communication direction 402 is any other value, the busy flag is set to “00”. The busy flags of slots other than the above are set to “00”.

  The subsequent operation of transmitting beacon data from the beacon generation unit 209 to the frame configuration unit 207 and configuring the frame by the frame configuration unit 207 and then transmitting the beacon via the wireless processing unit 201 Is the same.

  Next, when receiving the beacon in which the same slot reservation information is described from the communication partner, the transmitting wireless communication apparatus determines that the slot reservation has been established as a result of the beacon receiving process.

  Then, the upper layer processing unit 204 of the transmission side wireless communication apparatus sends the generated data to the frame configuration unit 207. The frame configuration unit 207 adds a header to the received data and then sends it to the wireless processing unit 201.

  Then, the wireless processing unit 201 transmits data from the antenna 200 in the slot designated by the data period.

  The above is the operation when data is unidirectionally transmitted from the wireless communication apparatus.

  Note that the slot determination method when performing the slot reservation described above determines that communication in the slot is possible when there is no transmitter or only a receiver in the vicinity of the communication partner. In order to perform spatial reuse, it is preferable to select a reserved slot rather than a slot that is not reserved in a neighboring wireless communication device. FIG. 7 is a flowchart showing such a dense slot determination method.

  In FIG. 7, first, the slot determination unit 215 refers to the reserved communication slot 404 of the slot reservation table and determines whether or not reservations are made in order from the first slot (step S701). If reserved, the beacon generation unit 209 refers to the communication direction 402 corresponding to the slot, and determines whether the communication direction is bidirectional communication (“11”) or the reception side (“01”). Confirmation (step S702). In the case of bidirectional communication (“11”) or the receiving side (“01”), the process proceeds to step S707 to determine the next slot.

  On the other hand, when it is not the two-way communication (“11”) or the receiving side (“01”) and there is no slot reservation in step S701, the slot determination unit 215 performs wireless communication on the surrounding state of the wireless communication device that is the communication partner. Obtained from the device ambient status table. When the busy state 412 of the corresponding slot number 411 is “01” (step S703), the slot ID is recorded in the reserved slot list A in the recording unit 206 (step S704).

  If the busy state 412 of the corresponding slot number 411 is “00” (step S705), the slot ID is recorded in the reserved slot list B in the recording unit 206 (step S706).

  Further, if the busy state 412 of the corresponding slot number 411 is “10”, it is determined that communication is impossible, and the process proceeds to step S707 to check the next slot.

  Next, the slot determination unit 215 determines whether or not the above steps S701 to S706 have been completed up to the final slot ID (step S707), and if not completed, the process proceeds to step S701 to check the next slot. To return.

  On the other hand, when the slot determination unit 215 completes the check up to the last slot ID, the slot determination unit 215 selects a slot necessary for communication from the reserved slot list A in the recording unit 206. Then, the bit of the corresponding slot position in the reserved slot 314 of the slot reservation information 301 is set (step S708).

  Next, the slot determination unit 215 checks whether or not the number of slots necessary for transmitting the transmission data has been selected (step S709), and if the number of slots is sufficient, the slot determination process ends.

  On the other hand, when the number of slots is insufficient, the slot determination unit 215 selects a slot necessary for communication from the reserved slot list B in the recording unit 206. Then, the slot determination unit 215 sets the bit at the corresponding slot position in the reserved slot 314 of the slot reservation information 301 (step S710).

  As described above, the slot determination unit 215 determines a slot to be reserved.

  As a result, the slot to be used this time is selected from the slots that have already been reserved but can be used for communication, so that the spatial utilization efficiency of the slot can be improved.

  Next, the operation when the receiving wireless communication apparatus receives data will be described below. The following description will be made assuming that a beacon ACK is requested.

  First, the radio processing unit 201 extracts a frame from the radio wave received by the antenna 200 and sends the frame to the frame determination unit 202.

  When the received frame is a data frame, the frame determination unit 202 records the frame ID in the recording unit 206 and sends the payload of the received frame to the upper layer processing unit 204. The upper layer processing unit 204 processes the received payload by an application. At this time, since the unidirectional communication is performed in the present embodiment, the upper layer processing unit 204 does not create response data. However, when the upper layer processing unit 204 has successfully received the data, the beacon generation processing unit 209 requests a beacon ACK response.

  The beacon generation processing unit 209 generates an ACK list 303 in which ACK (‘1’) is set at the position of the frame ID recorded in the recording unit 206. The ACK list 303 is arrival confirmation information. Further, the slot reservation information 301 and the slot busy flag 302 are generated in the same manner as the beacon transmission described above.

  Next, the beacon generation unit 209 transmits the generated beacon data including the slot reservation information 301, the slot busy flag 302, and the ACK list 303 to the frame configuration unit 207.

  After receiving this beacon data, the frame configuration unit 207 adds a beacon header to configure a beacon frame and sends it to the wireless processing unit 201.

  Then, the wireless processing unit 201 emits a beacon from the antenna 200 at a predetermined timing.

  The above is the operation of transmitting a beacon ACK after receiving data from the receiving-side wireless communication device. Even when performing unidirectional transmission in this way, whether or not the beacon ACK is normally received is determined. The device can know. For this reason, frames for which the beacon ACK designation bit is not set can be retransmitted in the next round slot, so that the same communication quality as bidirectional communication can be ensured even in unidirectional communication. become.

  Next, the operation of the reception-side wireless communication apparatus when starting a communication by performing slot reservation from a wireless communication apparatus that receives data in one direction will be described.

  First, the upper layer processing unit 204 instructs the beacon generation unit 209 to reserve a slot for reception when receiving data from another wireless communication device.

  In response to this slot reservation instruction, the beacon generation unit 209 determines a data slot by the following processing and generates slot reservation information.

  FIG. 5 is a flowchart illustrating a slot determination method for unidirectional communication.

  In FIG. 5, first, the slot determination unit 215 refers to the reserved communication slot 404 of the slot reservation table and determines whether or not reservations are made in order from the first slot (step S501). If reserved, the slot determination unit 215 refers to the communication direction 402 corresponding to the slot and determines whether the communication direction is bidirectional communication (“11”) or the transmission side (“10”). Confirmation (step S502). In the case of bidirectional communication (“11”) or transmission side (“10”), the reserved communication may be hindered, so that slot cannot be used. The process proceeds to step S507.

  On the other hand, if it is not the bidirectional communication (“11”) or the transmission side (“10”), and if there is no slot reservation in step S501, the slot determination unit 215 wirelessly determines the surrounding state of the wireless communication device that is the communication partner. It is determined from the communication device ambient situation table. When the busy state 412 of the corresponding slot number 411 is “00” or “10” (step S503), the beacon generation unit 209 does not transmit or transmits at least the other wireless communication device. Since there is no wireless communication device, it is determined that the partner wireless communication device can transmit, and the bit at the corresponding slot position in the reserved slot 314 of the slot reservation information 301 is set (step S504).

  Further, when the busy state 412 of the corresponding slot number 411 is “10”, the beacon generation unit 209 cannot communicate with the other party of communication that is being transmitted / received or that there is a wireless communication device that is transmitting in the vicinity. If it is determined that there is, the process proceeds to step S507 to check the next slot.

  Next, the slot determination unit 215 checks whether or not the number of slots necessary for transmitting the transmission data has been selected (step S505), and if the number of slots is sufficient, the slot determination process ends. Then, the communication direction indication unit 213 enters the ID of the target wireless communication apparatus in the counterpart DEV 311, and enters “01” indicating the receiving side in the communication direction 312. The priority 313 and the beacon ACK 315 are set so as to satisfy the communication quality (QoS) requested from the higher layer processing unit 204 (step S506).

  On the other hand, if the number of slots is insufficient, it is determined whether or not the above steps S501 to S505 have been completed up to the final slot ID (step S507). If not completed, the process proceeds to step S501 again to determine the next slot.

  As described above, the communication direction indication unit 213 and the slot determination unit 215 generate the slot reservation information 301.

  Next, the busy slot clarification unit 214 fills the slot busy flag 302 with its surrounding communication status based on the slot reservation table. That is, the busy slot clarification unit 214 sets “00” at the slot position reserved by the slot reservation information to indicate that it is not transmitting / receiving and the surrounding wireless communication device is not transmitting / receiving, and slot reservation is performed. For other slot positions recorded in the table, the slot busy flag is determined based on the information of the communication direction 402. For example, if at least one wireless communication device that is bidirectional (“11”) or transmitting (“10”) is recorded in the communication direction 402, the busy flag is “11”, and the communication direction 402 If only the wireless communication device on the receiving side (“01”) is recorded, the busy flag is “01”, and the information on the communication direction 402 is “00” for the busy flags of slots other than the above.

  Next, the beacon generation unit 209 transmits beacon data including the generated slot reservation information 301 and the slot busy flag 302 to the frame configuration unit 207.

  After receiving this beacon data, the frame configuration unit 207 adds a beacon header to configure a beacon frame and sends it to the wireless processing unit 201.

  Then, the wireless processing unit 201 emits a beacon from the antenna 200 at a predetermined timing.

  As described above, the beacon reserved for the slot is transmitted from the wireless communication apparatus on the receiving side.

  The wireless communication device requested to become a communication partner receives this beacon, and records the slot reservation information and the DEV_ID of the beacon transmission source wireless communication device in the recording unit 206 as communication reservation information.

  The wireless communication device on the transmission side performs the above-described beacon reception process, and if transmission is possible, accepts slot reservation and transmits a beacon in which slot reservation information of the same content is described.

  Thereafter, the transmitting-side wireless communication device performs data transmission with a data period, and the operation at that time is the same as the above-described data transmission operation.

  The above is the operation / action of the wireless communication apparatus in this embodiment.

  Next, a communication operation when the wireless communication apparatus according to the present embodiment is arranged at the position shown in FIG. 1 will be described.

  In FIG. 1, when the wireless communication devices B, C, and D are located in the communicable area 111 of the wireless communication device A, and the wireless communication devices A, E, and F are located in the communicable area 112 of the wireless communication device D, To do. The wireless communication device C performs unidirectional transmission to another wireless communication device, and the wireless communication device D performs unidirectional reception from the other wireless communication device. In addition, the wireless communication device B and the wireless communication device F are not communicating.

  At this time, the wireless communication device C transmits a beacon including slot reservation information and a slot busy flag used for unidirectional transmission, and the wireless communication devices B and D receive a beacon including a slot busy flag.

  Therefore, in the wireless communication device A, the wireless communication devices B, C, and D are located in the surrounding area, that is, in the communicable area 111, the wireless communication device C is in a unidirectional transmission state, and the wireless communication devices B and D are Know that you are not communicating. Further, the situation of the wireless communication devices around the wireless communication devices B, C, and D can also be known.

  Here, when the wireless communication apparatus A performs unidirectional transmission to the wireless communication apparatus D, the wireless communication apparatus A performs bidirectional communication around itself or is a receiving-side wireless communication apparatus. Check if it exists. In this example, the wireless communication device A can determine that such a wireless communication device is not in the vicinity.

  Next, the wireless communication device A checks whether or not there is a communication or a wireless communication device on the transmission side around the wireless communication device D that is a communication partner. The wireless communication device A can determine from the slot busy flag received from the wireless communication device D that there is no such wireless communication device.

  From the above two determination results, the wireless communication device A determines that unidirectional transmission to the wireless communication device D is possible, makes a slot reservation, and then starts transmission.

  In this embodiment, the wireless communication device is basically configured to perform unidirectional communication. However, the present invention is not limited to this, and bidirectional communication is basically performed. If communication conditions are not met, unidirectional communication is performed. May be performed.

As a communication condition when the wireless communication apparatus performs bidirectional communication, the slot determination unit 215 determines whether or not the target slot is reserved for transmission or reception. Use in is considered impossible. Also, if there is a wireless communication device that is transmitting or receiving in the target slot around the communication partner, use in that slot is regarded as impossible.

  As described above, when the wireless communication device performs bidirectional communication, transmission or reception is performed in one direction as compared with the condition that there is no transmitter / receiver in the vicinity of the wireless communication device on the transmission side and the reception side. In this case, communication can be performed even if there is a transmitter or a receiver in the vicinity of the transmitting side wireless communication device or the receiving side wireless communication device, respectively. As a result, the wireless communication apparatus can determine whether communication is possible under a wide range of conditions.

  Furthermore, in the present invention, since the ACK response is included in the beacon, frame loss can be detected even in unidirectional communication, and communication quality can be ensured by retransmission.

  In the present embodiment, an example of an autonomous distributed network is given. However, the present invention is not limited to this, and the present invention is also effective in an autonomous distributed network using other TDMA slots.

  INDUSTRIAL APPLICABILITY The present invention is useful for a wireless communication method and a wireless communication apparatus when performing ad hoc communication, and is suitable for spatial band reuse in a TDMA system or a hybrid system autonomous distributed network with TDMA.

Arrangement diagram of radio communication apparatus in radio communication network in embodiment Configuration diagram of radio communication apparatus in this embodiment Configuration diagram of beacon frame in the present embodiment (A) Configuration diagram of slot reservation table in the present embodiment (b) Configuration diagram of communication device surrounding status table in the present embodiment Flowchart for determining a unidirectional communication slot by a receiver in the present embodiment Flowchart for determining a unidirectional communication slot by the transmission side in the present embodiment Flowchart for determining a unidirectional communication slot in the present embodiment Configuration diagram of the super frame in the conventional example Configuration diagram of the super frame in the conventional example Configuration diagram of wireless communication device in conventional example

Explanation of symbols

200 Antenna 201 Radio Processing Unit 202 Frame Determination Unit 203 ACK / Retransmission Processing Unit 204 Upper Layer Processing Unit 205 Beacon Reception Processing Unit 206 Recording Unit 207 Frame Configuration Unit 208 Retransmission Frame Buffer Unit 209 Beacon Generation Unit 212 Communication Availability Determination Unit 213 Communication Direction Explicit section 214 Busy slot clarification section 215 Slot determination section

Claims (9)

A wireless communication method for realizing time division communication in an ad hoc network,
A wireless communication device designates a specific data transmission slot and reserves another wireless communication device for use in unidirectional transmission, unidirectional reception, or bidirectional communication;
Managing the reservation status reserved by the wireless communication device from other wireless communication devices;
Generating, based on the reservation status, the wireless communication device generating slot information indicating whether transmission or reception in a data transmission slot is possible, and notifying other wireless communication devices;
A step of determining a data transmission slot to be used from the reservation status managed by the wireless communication device when the wireless communication device performs unidirectional transmission or unidirectional reception and the slot information notified from the wireless communication device of the communication partner; A wireless communication method comprising: Determining the data transmission slot comprises:
Detecting a data transmission slot in which the wireless communication device is performing two-way communication from the reservation status, or a wireless communication device that is a receiving side is not present;
The wireless communication device detects a data transmission slot from which the wireless communication device of the communication partner is not transmitting / receiving from the slot information and the wireless communication device in the communicable area of the communication partner is not transmitting; ,
The wireless communication method according to claim 1, further comprising a step of determining that the data transmission slot detected in common in both of the detection steps is a data transmission slot used for communication. Determining whether communication is possible when the wireless communication device of the communication partner receives the reservation from the wireless communication device of the communication request source;
The wireless communication method according to claim 1, further comprising: reserving the same data transmission slot to the communication request source wireless communication device when the communication partner wireless communication device determines that communication is possible. The time division communication is performed in a superframe period composed of a beacon period for transmitting a beacon and a data period for transmitting data,
The wireless communication method according to claim 1, wherein the reservation of the data transmission slot and the slot information are notified by the beacon. A step of notifying the arrival confirmation information by a beacon in a next super frame when the wireless communication device of the communication partner normally receives data reserved for unidirectional transmission from the wireless communication device of the communication request source; Item 5. The wireless communication method according to Item 4. A wireless communication device constituting a wireless network for realizing time division communication in an ad hoc network,
A communication direction specifying unit for designating a data transmission slot and notifying a neighboring node that the data transmission slot is a transmitter / receiver of bidirectional communication, a sender or receiver of unidirectional communication, and
In each data transmission slot, a busy slot indication unit for notifying neighboring nodes whether transmission or reception is possible, and
A slot information receiving unit that receives the communication direction information notified from the communication direction specifying unit of another wireless communication device and the slot busy information notified from the busy slot specifying unit;
A wireless communication apparatus comprising: a slot determining unit that determines a data transmission slot to be used from communication direction information and slot busy information received by the slot information receiving unit when performing unidirectional communication. The slot determination unit detects a data transmission slot in which there is no wireless communication device performing bidirectional communication and a wireless communication device on the receiving side from the communication direction information, and further, the communication partner wireless communication device From the slot busy information, a data transmission slot in which the communication partner's wireless communication device is not transmitting / receiving and a wireless communication device in the communication partner's communicable area is not transmitting is detected in common. The wireless communication apparatus according to claim 6, wherein the detected data transmission slot is determined as a data transmission slot to be used for communication. When the slot information receiving unit receives a communication request from another wireless communication device, the slot information receiving unit has a communication enable / disable determining unit that determines whether communication is possible,
The wireless communication according to claim 6, wherein when the communication enable / disable determining unit determines that communication is possible, the wireless communication device instructs the communication direction specifying unit to notify the communication request source wireless communication device of its own communication direction in the same data transmission slot. Communication device. The time division communication is performed in a superframe period composed of a beacon period for transmitting a beacon and a data period for transmitting data,
A data receiving unit for receiving a data frame transmitted unidirectionally in a data transmission slot;
A data reception determination unit that determines whether or not the data reception unit has been normally received;
When it is determined that the data reception determination unit is normal reception, a beacon transmission unit that transmits information including arrival confirmation information during beacon transmission in the superframe lap or the next lap,
The wireless communication device according to claim 6, comprising:

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