JP4529636B2 - Wireless communication system and wireless communication apparatus - Google Patents

Description

  The present invention relates to a radio communication system and a radio communication apparatus, and more particularly to a radio communication system and a radio communication apparatus having a feature in priority contention access control (prioritized contention access).

  In recent years, a technical study of a high-speed wireless PAN that forms a small-scale network using an ultra-wideband wireless communication system has been performed (for example, see Patent Document 1). As such a system, two systems, a DS-SS system and a multiband OFDM (Orthogonal Frequency Division Multiplexing) system are being studied.

  In particular, the use of a communication method based on priority contention access control (prioritized contention access) is being studied as a media access control method (MAC) in multiband OFDM. This priority contention access control method is defined for each access category added to data with a difference in the transmission start time according to the priority, and when the data is transmitted, the transmission start time is defined. This is a communication method in which data can be transmitted if no other communication is started before the elapse of time.

  In addition, the multi-band OFDM media access control method (MBOA_MAC) was devised as a system that performs communication that guarantees QoS (Quality of Service) by using bandwidth reservation communication in addition to wireless communication by priority order competitive access control. Yes. MBOA_MAC uses the available area information (Availability_IE) in the beacon signal, reports the time that is not used by the distributed reservation protocol as an available area, and uses priority contention access control in this area. A method of performing communication is being studied.

  MBOA_MAC also has a mechanism for indicating to the receiver wireless communication device that the data to be transmitted is buffered by using beacon signal receiver communication device identification information (TIM (Traffic Indication Map) _IE). ing. At present, it is presumed that the communication based on the priority contention access control is performed on the part designated by the Availability_IE for the device designated by the TIM_IE by combining the TIM_IE and the Availability_IE.

IEEE 802.15.3a TI Document <URL: http://grouper.ieee.org/groups/802/15/pub/2003/May03 File name: 03142r2P802-15_TI-CFP-Document.doc>

  Incidentally, the priority contention access control method defined in the multiband OFDM has the following problems.

  That is, since all wireless communication devices start accessing at the same time, when data of the same access category is stored, there is a danger that transmission occurs simultaneously and collision occurs in these data transmissions. .

  In addition, when used together with bandwidth reservation communication, priority order contention access control often starts immediately after the completion of these reservation communications. It was to promote data transmission conflicts in access control communications.

Moreover, the use of communication by priority contention access control in all space available in Availability_IE, possibly communication by priority contention access control will be performed in all regions themselves showed available (time) This increases the risk of collisions.

  In addition, there is a problem in that communication by the priority contention access control is started in spite of an operation state in which the device is in an intermittent operation or the like and is not ready for reception.

  In addition, since it becomes a method of performing communication using all of the available time (bandwidth) without setting an area originally necessary for communication according to the amount of buffered data, a wireless communication device that needs to receive is Therefore, there is a problem in that it is necessary to wait for reception in the entire time (bandwidth), and the low power consumption operation cannot be performed.

  The present invention has been made in view of the above-described problems of conventional wireless communication systems and wireless communication devices, and an object of the present invention is to avoid collision of transmission / reception data with surrounding wireless communication devices. New and improved wireless communication that can provide a priority contention access control (prioritized contention access) method that enables low power consumption operation by setting the required communication area (communication time zone) A system and a wireless communication device are provided.

  In order to solve the above-described problems, the present invention provides a method for setting a minimum necessary priority contention access control area while coexisting with surrounding wireless communication devices in each wireless communication device. First, the present invention will be described conceptually.

  In the present invention, the dormant wireless communication device uses the available area information (Availability_IE) to notify that it is not desired to perform communication by priority contention access control, and useless transmission access control. Eliminate communication area by as much as possible. Specifically, the setting of the minimum necessary priority contention access control area is reported as an available state in the available area information (Availability_IE), thereby informing the surrounding wireless communication apparatuses of the setting of the used area. .

  Further, when transmission data is buffered, the destination wireless communication device is specified by the reception destination communication device identification information (TIM_IE), and further communication is required when communication by priority order contention access control is desired. The lowest area (time) to be used is notified as the available area by the available area information (Availability_IE). Then, the wireless communication device that is the reception destination specified by the reception destination communication device identification information (TIM_IE) from the transmission source communication device in which the transmission data is buffered is the available area information (Availability_IE) of the transmission source communication device. The receiving operation is performed in the area synchronized with.

  The present invention has been conceptually described above. The specific configuration of the present invention is as follows.

  According to the first aspect of the present invention, there is provided a wireless communication system in which a plurality of wireless communication devices form an ad hoc network. The wireless communication system of the present invention performs priority contention access control so that each wireless communication device does not overlap a communication area (for example, a communication time zone) set by an adjacent wireless communication device (minimum necessary). When a communication area is set and transmission data is buffered in one wireless communication device (transmission source wireless communication device), one or more other wireless communication devices (one or more other reception devices) that receive the transmission data ( A reception destination wireless communication device) is requested to receive in a communication area where priority contention access control is performed, and wireless communication based on priority contention access control is performed when the communication area where priority order contention access control arrives. (Claim 1).

  According to such a wireless communication system, a communication area (for example, a communication time zone) used by each wireless communication device as a minimum priority priority contention access control (prioritized contention access) is set in advance and transmitted. When the data is buffered, the receiving wireless communication apparatus is requested to receive in the communication area. A communication area for performing priority order competitive access control set in each wireless communication apparatus is set so as not to overlap with a communication area set in an adjacent wireless communication apparatus. By performing such priority contention access control, collision of data transmission with the same priority set is prevented, and low power consumption operation is possible by setting the minimum necessary communication area (time). Further, for example, when overlapping with a communication area set by an adjacent wireless communication device, a collision of data transmission can be prevented by combining the above priority order competitive access control and control by a backoff time (random backoff time). It can be avoided by two-stage control.

  In the above wireless communication system, the following applications are possible. For example, when transmission data for two or more other wireless communication devices (reception destination wireless communication devices) is buffered in one wireless communication device (transmission source wireless communication device), each of the other wireless communication devices (Sender's wireless communication device) is requested to receive simultaneously in the communication area that performs priority contention access control, and performs wireless communication using priority contention access control when the communication area that performs priority contention access control arrives. (Claim 2).

  In addition, in one wireless communication device (source wireless communication device), a communication area in which priority contention access control is performed when a buffered data amount of transmission data is detected and a predetermined buffer usage amount is exceeded. Can be increased (claim 3). In addition, when a buffered data amount of transmission data is detected and reduced to a predetermined buffer usage amount in one wireless communication device, setting of a communication area for performing priority contention access control may be reduced. It is possible (Claim 4). As described above, it is possible to increase or decrease the communication area (for example, communication time zone) in which priority contention access control is performed according to the amount of data in which transmission data is buffered.

  According to a second aspect of the present invention, a wireless communication device constituting an ad hoc network is provided. The wireless communication apparatus of the present invention sets a communication area for performing priority order contention access control (minimum necessary) so as not to overlap a communication area (for example, a communication time zone) set by an adjacent wireless communication apparatus. When the transmission data is buffered, the reception of the transmission data in the communication area where priority contention access control is performed is requested to one or two or more reception wireless communication apparatuses which are reception destinations of the transmission data. Radio communication by priority contention access control is performed when a communication area for contention access control arrives (claim 5).

  According to such a wireless communication device, a communication area (for example, a communication time zone) to be used as minimum necessary priority contention access control (prioritized contention access) is set in advance, and transmission data is buffered. If this happens, the receiver wireless communication device is requested to receive in the communication area. A communication area for performing priority order competitive access control set in each wireless communication apparatus is set so as not to overlap with a communication area set in an adjacent wireless communication apparatus. By performing such priority contention access control, collision of data transmission with the same priority set is prevented, and low power consumption operation is possible by setting the minimum necessary communication area (time). Further, for example, when overlapping with a communication area set by an adjacent wireless communication device, a collision of data transmission can be prevented by combining the above priority order competitive access control and control by a backoff time (random backoff time). It can be avoided by two-stage control.

  In the above wireless communication apparatus, the following applications are possible. For example, when transmission data for two or more receiving wireless communication devices is buffered, the receiving wireless communication devices are requested to simultaneously receive in the communication area for performing priority contention access control, It is possible to perform wireless communication by priority contention access control when a communication area where priority order contention access control is performed (claim 6).

  Further, when the buffered data amount of the transmission data is detected and the predetermined buffer usage amount is exceeded, it is possible to increase the setting of the communication area for performing priority contention access control. ). Further, when the buffered data amount of the transmission data is detected and reduced to a predetermined buffer usage amount, it is possible to reduce the setting of the communication area for performing the priority contention access control. ). As described above, it is possible to increase or decrease the communication area (for example, communication time zone) in which priority contention access control is performed according to the amount of data in which transmission data is buffered.

  In addition, another wireless communication device of the present invention performs (priority necessary) competitive contention access control so as not to overlap a communication region (for example, a communication time zone) set by an adjacent wireless communication device. A communication region setting unit (for example, a self-communication device region setting unit 807 described later), a data buffer for buffering transmission data (for example, a data buffer 814 described later), and a buffered data amount of the transmission data A buffer usage amount detecting unit (for example, a buffer usage amount detecting unit 810 described later), and one or two or more receiving destination wireless communication devices that receive the transmission data when the transmission data is buffered Priority request contention in the communication area that performs priority contention access control and priority contention when the communication area that performs priority contention access control arrives Communication unit that performs wireless communication by access control (e.g., a wireless transmission unit 811 to be described later) and further comprising a, a (claim 9).

  According to such a wireless communication device, a communication area (for example, a communication time zone) to be used as minimum necessary priority contention access control (prioritized contention access) is set in advance, and transmission data is buffered. If this happens, the receiver wireless communication device is requested to receive in the communication area. A communication area for performing priority order competitive access control set in each wireless communication apparatus is set so as not to overlap with a communication area set in an adjacent wireless communication apparatus. By performing such priority contention access control, collision of data transmission with the same priority set is prevented, and low power consumption operation is possible by setting the minimum necessary communication area (time). Further, for example, when overlapping with a communication area set by an adjacent wireless communication device, a collision of data transmission can be prevented by combining the above priority order competitive access control and control by a backoff time (random backoff time). It can be avoided by two-stage control.

  In the above wireless communication apparatus, the following applications are possible. For example, when transmission data for two or more receiver wireless communication devices is buffered in the data buffer, the communication unit performs communication in the communication area where priority competition access control is performed for each receiver wireless communication device. Wireless communication based on priority contention access control can be performed when a communication area for performing priority contention access control is received (claim 10).

  Further, the communication area setting unit can increase the setting of the communication area for performing priority contention access control when the buffer usage detection unit detects that the predetermined buffer usage has been exceeded. Item 11). The communication area setting unit can also reduce the setting of the communication area for performing priority contention access control when the buffer usage detection unit detects that the buffer usage has been reduced to a predetermined buffer usage. Item 12). As described above, it is possible to increase or decrease the communication area (for example, communication time zone) in which priority contention access control is performed according to the amount of data in which transmission data is buffered.

  According to another aspect of the present invention, there are provided a program for causing a computer to function as the wireless communication device, and a computer-readable recording medium on which the program is recorded. Here, the program may be described in any programming language. In addition, as a recording medium, for example, a recording medium that is currently used as a recording medium capable of recording a program, such as a CD-ROM, a DVD-ROM, or a flexible disk, or any recording medium that is used in the future should be adopted. Can do.

  As described above, according to the present invention, a communication area (for example, a communication time zone) to be used by each wireless communication apparatus as minimum necessary priority contention access control (prioritized contention access) is set in advance. When the transmission data is buffered, the receiving wireless communication apparatus is requested to receive in the communication area. A communication area for performing priority order competitive access control set in each wireless communication apparatus is set so as not to overlap with a communication area set in an adjacent wireless communication apparatus. By performing such priority contention access control, collision of data transmission with the same priority set is prevented, and low power consumption operation is possible by setting the minimum necessary communication area (time). Further, for example, when overlapping with a communication area set by an adjacent wireless communication device, a collision of data transmission can be prevented by combining the above priority order competitive access control and control by a backoff time (random backoff time). It can be avoided by two-stage control.

  In addition, by notifying the communication area used for priority contention access control by the available area information (Availability_IE), it is possible to notify the surrounding wireless communication apparatus of the communication area of its own priority contention access control.

  In addition, by periodically notifying such information using a beacon signal, the surrounding wireless communication devices can always grasp the communication area for priority contention access control of the wireless communication device.

  In addition, by setting the minimum available area, it is possible to set this priority contention access control while avoiding the area used by the surrounding wireless communication devices.

  In addition, by setting the available area to be distributed among the wireless communication devices, it is possible to avoid collision of data transmissions of the same access category from other wireless communication devices.

  Also, by increasing / decreasing the required priority contention access control setting according to the amount of transmission data buffered, unnecessary reception operations are not required for other wireless communication devices. There is an effect.

  Further, since the sleep operation can be performed in an area other than the minimum necessary available area set at the beginning, a low power consumption operation can be realized.

  Also, if the wireless communication device has a minimum usable area, other wireless communication devices in the surrounding area refrain from communication in that area. The risk of falling into a locked state is reduced.

  In addition, when there is no more space in the area (time) used for priority contention access control with surrounding wireless communication apparatuses, the area (time) set for use in other wireless communication apparatuses is also included. By setting the use together, communication with higher priority can be started from its own wireless communication device prior to communication with lower priority to be transmitted by another wireless communication device. In this case, it is possible to reduce communication collisions by minimizing the area (time) overlapping with transmissions of other wireless communication devices as much as possible.

  Exemplary embodiments of a wireless communication system and a wireless communication apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(1) Configuration of Ad Hoc Network FIG. 1 shows the configuration of an ad hoc network. Here, as an example, a state is shown in which five wireless communication devices 111 to 115 form an ad hoc network 100 with surrounding wireless communication devices. Note that in this specification, the wireless communication device refers to a device capable of at least wireless communication, and is not limited to a device capable of only wireless communication.

  A region indicated by a broken line in FIG. 1 indicates a radio wave reachable range from the wireless communication device located at the center. That is, the wireless communication device 111 can communicate with the wireless communication device 112 within the radio wave reachable range 121, and the wireless communication device 112 communicates with the radio communication device 111 and the radio communication device 113 within the radio wave reachable range 122. The wireless communication device 113 can communicate with the wireless communication device 112 and the wireless communication device 114 in the radio wave reachable range 123, and the wireless communication device 114 is in the radio wave reachable range 124. 113 and the wireless communication device 115 can communicate with each other, and the wireless communication device 115 can communicate with the wireless communication device 114 within the radio wave reachable range 125.

(2) Superframe Configuration FIG. 2 shows a configuration example of the superframe. Here, as an example, (A) a superframe period is defined at a predetermined time, and (B) a management area and (C) a data transmission area are arranged in the superframe. In the example shown in FIG. 2, a total of 256 access slots from 0 to 255 are arranged in the superframe, and each wireless communication apparatus can perform communication as needed in this access slot.

  (B) In the management area, the wireless communication devices constituting the ad hoc network each transmit a beacon signal. Here, a transmission area for beacon signals different from other wireless communication apparatuses is arranged in the management area. Each wireless communication device 111 to 115 transmits and receives beacon signals in this management area, thereby grasping the wireless communication device existing in the surrounding area and adjusting the data transmission area to be used with the surrounding wireless communication device. It is possible. The arrangement of the beacon signal transmission area will be described later with reference to FIG.

  In this embodiment, it is assumed that (B) the access slots from 0 to 19 are appropriately used as the management area. In the ad hoc network (FIG. 1) as in the present embodiment, it is assumed that up to about 60 wireless communication devices exchange beacon signals with each other. Therefore, in order to prevent collision of beacon signals even if up to about 60 wireless communication apparatuses exchange beacon signals with each other, (B) 0 to 19 access slots are prepared in the management area. .

  (C) In the data transmission area, a time band used for communication is set according to the demand of each wireless communication device. In this embodiment, (C) 20 to 255 access slots are appropriately used as the data transmission area.

(3) Transmission position of beacon signal FIG. 3 shows a configuration example of the beacon transmission position in the management area. FIG. 3 shows a configuration example in the case where each wireless communication device forming the ad hoc network places the beacon transmission areas in a distributed manner in the superframe management area. Note that the wireless communication devices 111 to 115 form the ad hoc network 100 shown in FIG. 1, and as described above, the wireless communication device 111 can communicate with the wireless communication device 112, and the wireless communication device 112 is wireless. The communication device 111 can communicate with the wireless communication device 113, the wireless communication device 113 can communicate with the wireless communication device 112 and the wireless communication device 114, and the wireless communication device 114 can communicate with the wireless communication device 113 and the wireless communication device 115. And the wireless communication device 115 can communicate with the wireless communication device 114.

  Here, the wireless communication devices 111 to 115 define (B) access slot 0, (B1) access slot 1, (B2) access slot 2 in the management area, and beacon slot 0 to beacon slot 8 are defined. Each represents a state in which a beacon transmission position is set.

  That is, the first beacon slot 0 is arranged as an empty slot for convenience, the next beacon slot 1 is used as the beacon slot of the wireless communication device 111, and the next beacon slot 2 is used as the beacon slot of the wireless communication device 112. The next beacon slot 3 is used as the beacon slot of the wireless communication device 113, the next beacon slot 4 is used as the beacon slot of the wireless communication device 114, and the next beacon slot 5 is used as the beacon slot of the wireless communication device 115. It's being used.

  Also, empty beacon slots 6 to 8 are prepared for wireless communication apparatuses newly entering the ad hoc network 100.

  Here, a configuration may be adopted in which the number of beacon slots is increased or decreased in accordance with the number of wireless communication devices constituting the ad hoc network. Therefore, as described above, (B) the management area can be expanded to a maximum of 20 access slots, for example.

(4) Priority Conflict Access Control Method FIG. 4 shows an example of a priority conflict access control method. The priority contention access control method shown in FIG. 4 is a priority contention access control method in a wireless communication system compliant with IEEE802.11e, and is called EDCA (Enhanced Distributed Channel Access).

  In EDCA, the setting of AIFS (Arbitration Inter Frame Space) that starts transmission with a difference in transmission back-off timing according to the priority order (access categories 0 to 7) described in the access category of data to be transmitted Make a difference in value. And if other communication is not started over AIFS, data can be transmitted. That is, access category data with a high priority is transmitted with a short AIFS setting, and access category data with a low priority is transmitted with a long AIFS setting.

  At this time, the wireless communication apparatus which is going to transmit data with low priority waits for transmission by communication of other data with high priority within the AIFS setting time. In other words, this is an access control method that allows a communication device storing data with high transmission priority to preferentially transmit data to a wireless medium.

  In the example shown in FIG. 4, the access category 0 has the highest priority, and the priority is set up to the access category 7 below. The data of the access category 0 with the highest priority can be transmitted after AIFS [0] has elapsed. Next, access category 1 data with the highest priority can be transmitted after elapse of AIFS [1] = AIFS [0] + one backoff unit (one backoff slot).

  Similarly, access category 2 data can be transmitted after AIFS [2] = AIFS [0] + backoff 2 units, and access category 3 data can be transmitted by AIFS [3] = AIFS [0] + backoff 3 The data can be transmitted after the elapse of the unit, the access category 4 data can be transmitted after AIFS [4] = AIFS [0] + backoff 4 units, and the data of the access category 5 can be transmitted by AIFS [5] = AIFS [0]. + Data can be transmitted after 5 units of back-off, access category 6 data can be transmitted after AIFS [6] = AIFS [0] + 6 units of back-off, and data of access category 7 can be transmitted by AIFS [7] = The configuration is such that transmission is possible after elapse of AIFS [0] + backoff 7 units.

  However, in the priority order competitive access control method of EDCA, when there are a plurality of communication devices in which data of the same priority is buffered, the setting of the AIFS transmission waiting time becomes the same and transmitted simultaneously. Therefore, there was a problem that a collision occurred.

  In addition, a method for avoiding a collision by adding a random back-off time to the AIFS waiting time has been devised. However, when a random back-off time is added to the AIFS waiting time, if data with low priority is transmitted first without setting back-off, data with high priority cannot be transmitted with priority. It was happening.

(5) Frame Configuration of Beacon Signal FIG. 5 shows a frame configuration example of the beacon signal.
The beacon signal 50 of this embodiment is configured in the same manner as other data frames as a beacon frame, and as shown in FIG. 5, MAC header information 51, a header check sequence (HCS) 52, a beacon. It is composed of payload information 53, a frame check sequence (FCS) 54, and the like.

  The MAC header information 51 includes frame control information 501, destination identifier information 502, source identifier information 503, sequence control information 504, access control information 505, and the like.

  The beacon payload information 53 includes a network group parameter 506, distribution beacon slot offset information 507, usable area information 508, reception destination communication device identification information 509, distribution reservation slot information 510, communication device capability information 511, It consists of application definition information 512 and the like.

  Note that the beacon signal 50 illustrated in FIG. 5 is merely an example, and the information element (IE) may be added / reduced as necessary to form a beacon signal. In addition, information elements other than those described above may be defined and added to form a beacon signal.

  Hereinafter, usable area information (Availability_IE) 508 and receiving destination communication apparatus identification information (TIM_IE) 509, which are information elements (IE: Information Element) characteristic of the present embodiment, will be described.

(6) Configuration Example of Available Area Information (Availability_IE) FIG. 6 is a configuration example of available area information (Availability_IE). As shown in FIG. 6, the usable area information 508 according to the present embodiment includes an information element identifier 61, an information length 62, an available access slot bitmap 63, and the like.

  In other words, the area (time) that can be used by the wireless communication apparatus for priority order competitive access control is shown in units of access slots. Accordingly, the available access slot bitmap 63 is composed of, for example, a fixed length of 32 bytes.

(7) Configuration Example of Receiving Destination Communication Device Identification Information (TIM_IE) FIG. 7 is a configuration example of receiving destination communication device identification information (TIM_IE). As shown in FIG. 7, the receiving destination communication device identification information (TIM_IE) 509 according to the present embodiment includes an information element identifier 71, an information length 72 (variable length), receiving destination communication device identification information 73, and the like. Has been.

  The destination communication device identification information 73 describes the device identifier of the wireless communication device when transmission data from itself is buffered in the buffer. Therefore, the destination communication device identification information 73 is configured with a variable length (Variable).

  In addition, in order to notify a plurality of wireless communication devices that reception is necessary, the destination communication device identification information 73 is configured to be able to describe device identifiers of the plurality of wireless communication devices.

(8) Setting example of priority order competing access control area in each wireless communication apparatus FIG. 8 shows a setting example of priority order competing access control area (PCA) in each wireless communication apparatus. Here, a state is shown in which the wireless communication apparatuses 111 to 115 set different priority order conflict access control areas and set an area for performing communication by priority order conflict access control for the first time. Note that the wireless communication devices 111 to 115 form the ad hoc network 100 shown in FIG. 1, and as described above, the wireless communication device 111 can communicate with the wireless communication device 112, and the wireless communication device 112 is wireless. The communication device 111 can communicate with the wireless communication device 113, the wireless communication device 113 can communicate with the wireless communication device 112 and the wireless communication device 114, and the wireless communication device 114 can communicate with the wireless communication device 113 and the wireless communication device 115. And the wireless communication device 115 can communicate with the wireless communication device 114.

  As described above, (A) the superframe period is composed of (B) a management area and (C) a data transmission area (FIG. 2). (B) The beaconing period (BP) of the management area is set as an area where each of the wireless communication devices 111 to 115 transmits and receives a beacon signal. Then, (C) in the data transmission area, each of the wireless communication devices 111 to 115 sets a priority contention access control area (PCA) as follows.

  (C) The priority communication access control area (PCA) is set near the head of the data transmission area (C), and the map is constructed with bit 0 of the available area information (Availability_IE).

  (C) The priority communication access control area (PCA) is set near the center of the data transmission area, and the wireless communication apparatus 112 constructs a map with bit 0 of the available area information (Availability_IE).

  The wireless communication apparatus 113 sets (C) a priority contention access control area (PCA) in the vicinity of about ¼ from the head of the data transmission area, and sets the map as bit 0 of the available area information (Availability_IE). To construct.

  The wireless communication device 114 sets (C) a priority contention access control area (PCA) in the vicinity of about 3/4 from the beginning of the data transmission area, and maps it as bit 0 of the available area information (Availability_IE). To construct.

  The wireless communication device 115 sets (C) a priority contention access control area (PCA) in the vicinity of about 1/8 from the beginning of the data transmission area, and sets the map as bit 0 of the available area information (Availability_IE). To construct.

(9) Example of Setting Increase / Decrease in Priority Contention Access Control Area FIG. 9 shows an example of setting increase / decrease in the priority contention access control area (PCA). Here, an example of setting for increasing / decreasing the priority contention access control area in the wireless communication apparatus 113 is shown. As illustrated in FIG. 1, the wireless communication device 113 is a wireless communication device capable of communicating with the wireless communication device 112 and the wireless communication device 114.

  In setting level 1, the minimum necessary priority contention access control area is set when there is no transmission data or when there is minimum transmission data.

  In setting level 2, when transmission data exceeding a predetermined amount of information (1 unit) is buffered, the priority contention access control area (PCA) used by itself is expanded. This is an example in which an area is additionally set by extending the rear part.

  In setting level 3, when transmission data exceeding a predetermined amount of information (2 units) is buffered, the priority contention access control area (PCA) used by itself is extended further to the rear of the existing area. In this example, additional areas are set.

  At setting level 4, when transmission data exceeding a predetermined amount of information (3 levels) is buffered, the priority contention access control area (PCA) used by itself is extended to the front of the existing area. In this example, additional areas are set. The reason why the setting level 4 is expanded to the front of the existing area is as follows. As shown in FIG. 8, a priority contention access control area (PCA) of the adjacent wireless communication device 112 exists behind the area set at the setting level 3. The setting information of the priority contention access control area can be confirmed by a beacon signal transmitted from the wireless communication apparatus 112. Therefore, the priority contention access control area used by itself is extended to the front of the existing area so that the priority contention access control area of the wireless communication apparatus 113 does not overlap the priority contention access control area of the wireless communication apparatus 112. is doing.

  At setting level 5, when transmission data exceeding a predetermined amount of information (4 stages) is buffered, the priority contention access control area (PCA) used by other wireless communication devices can be used. This is an example in which additional settings are made even for parts that are not set. That is, the other wireless communication apparatuses 111, 112, 114, and 115 set priority contention access control areas (PCAs) in the areas shown in FIG. The setting information of the priority contention access control area can be confirmed by a beacon signal transmitted from the wireless communication devices 111, 112, 114, and 115. For this reason, the priority contention access control area used by the wireless communication device 113 is set so that the priority contention access control region of the wireless communication device 113 does not overlap with the priority contention access control regions of the other wireless communication devices 111, 112, 114, and 115. Additional settings have been made.

  At setting level 6, when transmission data exceeding a predetermined amount of information (5 levels) is buffered, the priority contention access control area (PCA) used by itself is set as (B) of the management areas. This is an example in which an area is additionally set by extending to the area in use.

At setting level 7, when transmission data exceeding a predetermined amount of information (six steps) is buffered, the priority contention access control area (PCA) used by itself is assigned to the adjacent wireless communication devices 112, 114. This is an example in which an area is additionally set by expanding to an area other than the priority conflict access control area in FIG.

At setting level 8, when transmission data exceeding a predetermined amount of information (7 levels) is buffered, the priority contention access control area (PCA) used by itself is extended to all areas. This is an example in which additional areas are set.

  As described above, in this embodiment, a communication area (for example, a communication time zone) in which priority contention access control is performed when the buffered data amount of transmission data is detected and a predetermined buffer usage amount is exceeded. It is possible to increase the setting.

  Further, when the buffered data amount of transmission data is detected and reduced to a predetermined buffer usage amount, it is also possible to reduce the setting of the communication area for performing priority contention access control. In this case, in accordance with the buffered data amount of the transmission data, the level is sequentially lowered from the current setting level, and the setting of the communication area for performing priority contention access control is reduced. As described above, it is possible to increase or decrease the communication area (for example, communication time zone) in which priority contention access control is performed according to the amount of data in which transmission data is buffered.

(10) Configuration Example of Wireless Communication Device FIG. 10 shows a configuration example of the wireless communication device according to the present embodiment.
As illustrated in FIG. 10, the wireless communication device 800 includes an antenna 801, a wireless reception unit 802, a beacon analysis unit 803, a peripheral communication device communication area determination unit 804, a data analysis unit 805, and an access control unit 806. A self-communication device area setting unit 807, a central control unit 808, a transmission data amount detection unit 809, a buffer usage amount detection unit 810, a wireless transmission unit 811, a beacon generation unit 812, and a transmission destination detection unit 813. And a data buffer 814 and an interface 815.

  First, the presence of surrounding wireless communication devices forming the ad hoc network is confirmed by exchanging a predetermined beacon signal. In the management area (FIG. 2, FIG. 8B), the beacon signal is received from the antenna 801 via the wireless receiver 802 under the control of the access controller 806, and the beacon signal is supplied to the beacon analyzer 803.

  The beacon analysis unit 803 passes predetermined information of the beacon frame to the peripheral wireless communication device communication area determination unit 804 and stores information on the communication area set in the wireless communication device.

  Further, information on wireless communication devices existing in the vicinity is also supplied to the central control unit 808 and stored in the internal memory of the central control unit as peripheral wireless communication device management information.

  Further, predetermined information of the beacon frame is supplied to the self-communication device region setting unit 807, information on the received wireless communication device and the beacon slot position is supplied to the beacon generation unit 812, and the own transmission beacon information As described.

  When a predetermined beacon transmission time has arrived, the wireless transmission unit 811 transmits the beacon signal via the antenna 801 under the control of the access control unit 806.

  Further, if there is a description of the reception request addressed to itself, self-communication device area setting unit 807 reads the priority order contention access control area information of the wireless communication apparatus from peripheral communication device communication area determination unit 804 and receives the self-reception. Set up.

  Further, when the reception time arrives, the data is received from the antenna 801 via the wireless reception unit 802 under the control of the access control unit 806, the data signal is supplied to the data analysis unit 805, and the received data is stored in the data buffer. Stored in 814.

  Then, the data is transferred to an application device (not shown) to be connected via the interface 815.

  Data to be transmitted from an application device (not shown) connected to the wireless communication apparatus is described in the data buffer 814 via the interface 815.

  By receiving the transmission data, transmission destination (address) information is supplied to the transmission destination detection unit 813. If there is a description in the peripheral wireless communication device management information, a reception request for the wireless communication device is generated and a beacon generation unit 812 is generated. And is described as its own transmission beacon information.

  Further, the buffering amount of the transmission data is supplied from the data buffer 814 to the buffer usage amount detection unit 810, and the buffering amount is monitored. When the predetermined amount is exceeded, the self-communication device region setting unit 807 , Additional setting of own communication area is made. In this case, the self-communication device region setting unit 807 determines a region that is not used by the surrounding wireless communication devices from the information stored in the peripheral communication device communication region determination unit 804.

  When a predetermined transmission time arrives, data is transmitted from the wireless transmission unit 811 as data via the antenna 801 under the control of the access control unit 806.

  The transmitted data amount is notified to the transmission data amount detection unit 809, and the released buffer amount is supplied to the buffer usage amount detection unit 810, and when it falls below the predetermined buffer usage amount, the communication device area setting unit 807 is notified. Thus, the setting is made to reduce the own communication area.

(11) Operation of Radio Communication Device FIG. 11 shows an operation flowchart of the radio communication device according to the present embodiment.
In the wireless communication apparatus according to the present embodiment, first, when power is turned on to the wireless communication apparatus, a beacon scan is set over a superframe period (step S101).

  If an existing beacon signal is not received (step S102), it becomes the first wireless communication device that forms an ad hoc network and sets a superframe (FIG. 2, (C)) (step S103). ).

  When a beacon signal is received, an empty beacon slot is searched from the beacon transmission position information, and a beacon transmission position is set (step S104).

  If the beacon transmission time has arrived in the management area (FIG. 2, FIG. 8B) (step S105), beacon information to be transmitted is collected and a beacon signal is transmitted (step S106).

  Further, when it is at the beacon reception time from the surrounding wireless communication device in the management area (step S107), the following operation is performed. First, if a beacon signal is received and a beacon signal is received (step S108), parameters of the received beacon signal are stored (step S109), and the priority order of the surrounding wireless communication devices is determined from the available area information (Availability_IE). The communication area setting status by competing access control is grasped (step S110). Furthermore, if the receiver itself is designated as the receiving destination in the receiving destination communication device identification information (TIM_IE) (step S111), the reception of the priority order contention access control area is set (step S112).

  After the above process, or when no beacon signal is received in step S108, or when the destination communication device identification information is not specified, the process returns to step S105, and the beacon reception process is continued as long as the management area continues.

  When data is buffered via the interface (step S113), if there is a wireless communication device that is the destination of the data (step S114), as shown in FIG. The identifier (device identifier) of the wireless communication device is added to the device identification information 509 (step S115).

  Further, the amount of buffered data is confirmed (step S116), and if it is necessary to add a priority contention access control area (step S117), the setting state of the priority contention access control area of the peripheral wireless communication device (Step S118), and if there is a free area (step S119), the area is additionally set as a priority contention access control area (step S120). However, in step S119, even if there is no free area, the self-priority conflict access control area may be increased.

  After the above processing, or when there is no free area and no addition is performed, when addition of an area is not necessary, or when addition is necessary but cannot be added, a series of processing is repeated.

  When the priority-order contention access control area set by itself arrives (step S121), the following operation is performed. First, if there is transmission data (step S122) and there is data with a higher priority (step S123), the data is transmitted to the receiving wireless communication apparatus after a predetermined back-off time (step S124). If an ACK is returned from the receiving wireless communication apparatus (step S125), the amount of transmitted data is detected (step S126). If the priority-order contention access control area can be reduced (step S127), the area is set to be reduced (step S128).

  After the above processing, or when it is not necessary to reduce the area in step S127, if no ACK is received in step S125, or if there is no higher priority data in step S123, the process returns to step S121 again, and priority order conflict access This transmission processing is repeated as long as the control area continues or until there is no transmission data.

  When the reception time set by the user has arrived (step S129), data reception processing is performed (step S130). If reception of the self-addressed data is started (step S131) and the data can be normally received (step S132), an ACK is returned to the transmission source wireless communication device (step S133).

  After this process is completed, or when data cannot be normally received in step S132, or when data addressed to itself is not received in step S131, the process returns to S129 again as long as the reception area set by itself continues. This reception process is continued.

  If the received self-addressed data can be output via the interface (step S134), it is output via the interface (step S135).

  Thereafter, when the head position of the super frame arrives again, the process returns to S105, and a series of operations are repeated.

(Effect of this embodiment)
As described above, according to the present embodiment, a communication area (for example, a communication time zone) used by each wireless communication device as minimum priority priority contention access control (prioritized contention access) is set in advance. In addition, when the transmission data is buffered, the reception wireless communication apparatus is requested to receive in the communication area. A communication area for performing priority order competitive access control set in each wireless communication apparatus is set so as not to overlap with a communication area set in an adjacent wireless communication apparatus. By performing such priority contention access control, it is possible to prevent collision of data transmissions with the same priority setting, and to operate with low power consumption by setting the minimum necessary communication area (time). Further, for example, when overlapping with a communication area set by an adjacent wireless communication device, a collision of data transmission can be prevented by combining the above priority contention access control and control by a backoff time (random backoff time). It can be avoided by two-stage control.

  The preferred embodiments of the wireless communication system and the wireless communication apparatus according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  The present invention can be used for a wireless communication system and a wireless communication apparatus, and in particular, can be used for a wireless communication system and a wireless communication apparatus having a feature in priority contention access control (prioritized contention access).

It is explanatory drawing which shows the structure of an ad hoc network. It is explanatory drawing which shows the structural example of a super frame. It is explanatory drawing which shows the structural example of the beacon transmission position in a management area | region. It is explanatory drawing which shows an example of the priority order conflict access control method. It is explanatory drawing which shows the structural example of a beacon signal. It is explanatory drawing which shows the structural example of usable area | region information (Availability_IE). It is explanatory drawing which shows the structural example of receiving destination communication apparatus identification information (TIM_IE). It is explanatory drawing which shows the example of a setting of the priority order competitive access control area | region in a radio | wireless communication apparatus. It is explanatory drawing which shows the example of an increase / decrease setting of a priority order contention access control area. It is explanatory drawing which shows the structural example of a radio | wireless communication apparatus. It is a flowchart which shows operation | movement of a radio | wireless communication apparatus.

Explanation of symbols

100 Ad hoc network 111, 112, 113, 114, 115 Wireless communication device 121, 122, 123, 124, 125 Radio wave reach 50 Beacon signal 50
51 MAC header information 52 Header check sequence (HCS)
53 Beacon payload information 54 Frame check sequence (FCS)
501 Frame control information 502 Delivery destination identifier information 503 Source identifier information 504 Sequence control information 505 Access control information 506 Network group parameter 507 Distribution beacon slot offset information 508 Available area information (Availability_IE)
509 Receiving destination communication device identification information (TIM_IE)
510 Distribution reserved slot information 511 Communication device capability information 512 Application definition information 61 Information element identifier 62 Information length 63 Available access slot bitmap 71 Information element identifier 72 Information length 73 Receiving destination communication device identification information 800 Wireless communication device 801 Antenna 802 Wireless Reception unit 803 Beacon analysis unit 804 Peripheral communication device communication region determination unit 805 Data analysis unit 806 Access control unit 807 Self communication device region setting unit 808 Central control unit 809 Transmission data amount detection unit 810 Buffer usage amount detection unit 811 Wireless transmission unit 812 Beacon generator 813 Destination detector 814 Data buffer 815 interface

Claims (12)

In a wireless communication system in which a plurality of wireless communication devices constitute an ad hoc network,
Each wireless communication device,
A communication area for performing priority contention access control in which transmission is started at a timing determined according to a priority order based on an access category of buffered data is set within a predetermined superframe period ,
Notify the information indicating the set communication area as available area information,
When transmission data is buffered in one wireless communication device, in the communication region notified to the one or two or more other wireless communication devices that receive the transmission data by the available region information requests received, and performs wireless communication by priority contention access control at the time of arrival of the previous SL communications area, a wireless communication system. In the one of the wireless communication device, when the transmission data for two or more of the other wireless communication device is buffering for each of the other wireless communication device, simultaneous reception of the previous SL communications area requests, and performs wireless communication by priority contention access control at the time of arrival of the previous SL communications area, the wireless communication system according to claim 1. In the one wireless communication apparatus, the communication area for minimum priority priority contention access control is set in advance so as not to overlap with an area set by an adjacent wireless communication apparatus, and the transmission data buffer detects the ring data amount, when the detected amount exceeds a predetermined buffer usage, and characterized by increasing the pre-Symbol communications area, the wireless communication system according to claim 1. In the one of the wireless communication device, and wherein said detecting the buffered data amount of the transmission data, when the detection amount is decreased to a predetermined buffer usage, to reduce the pre-Symbol communications area The wireless communication system according to claim 3 . In a wireless communication device constituting an ad hoc network,
A communication area for performing priority contention access control in which transmission is started at a timing determined according to a priority order based on an access category of buffered data is set within a predetermined superframe period ,
Notify the information indicating the set communication area as available area information,
When transmission data is buffered, one or more receiver wireless communication devices that are the receivers of the transmission data are requested to receive in the communication area notified by the available area information. and performs wireless communication by priority contention access control at the time of arrival of the serial communications area, the wireless communication device. If the transmission data for two or more of the received destination radio communication device is buffering for each of the receiver wireless communication device requests the simultaneous reception of the previous SL communications area, before Symbol communications 6. The wireless communication apparatus according to claim 5, wherein wireless communication is performed by priority contention access control when an area arrives. The communication area for minimum priority priority contention access control is set in advance so as not to overlap the area set by the adjacent wireless communication device, and the buffered data amount of the transmission data is detected. Te, when the detected amount exceeds a predetermined buffer usage, and characterized by increasing the pre-Symbol communications area, the wireless communication apparatus according to claim 5. Wherein detecting the buffered data amount of the transmission data, when the detection amount is decreased to a predetermined buffer usage, and wherein reducing the pre Symbol communications area, according to claim 7 Wireless communication device. In a wireless communication device constituting an ad hoc network,
A communication area setting unit for setting a communication area for performing priority contention access control in which transmission is started at a timing determined according to a priority order based on an access category of buffered data within a predetermined superframe period ;
A control unit for notifying information indicating the set communication area as usable area information;
A data buffer for buffering transmission data;
A buffer usage detector for detecting a buffered data amount of the transmission data;
When transmission data is buffered, one or more receiver wireless communication devices that are the receivers of the transmission data are requested to receive in the communication area notified by the available area information. A communication unit that performs wireless communication by priority contention access control when the communication communication area arrives;
A wireless communication device comprising: The communication unit
If the transmission data for two or more of the received destination radio communication device is buffered in the data buffer for each of the receiver wireless communication device requests the simultaneous reception of the previous SL communications area, and performs wireless communication by priority contention access control at the time of arrival of the previous SL communications area, the wireless communication apparatus according to claim 9. The communication area setting unit sets the communication area for minimum priority order conflict access control in advance so as not to overlap with an area set by an adjacent wireless communication device,
In case the detected amount detected by the buffer usage amount detection unit exceeds a predetermined buffer usage, and characterized by increasing the pre-Symbol communications area, the wireless communication apparatus according to claim 9 . The communication area setting unit
In case the detected amount detected is reduced to a predetermined buffer usage by the buffer usage amount detection unit, characterized in that to reduce the pre-Symbol communications area, the wireless communication apparatus according to claim 11 .

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