JP5391419B2 - Wireless device and wireless communication system including the same - Google Patents

Wireless device and wireless communication system including the same Download PDF

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JP5391419B2
JP5391419B2 JP2009038461A JP2009038461A JP5391419B2 JP 5391419 B2 JP5391419 B2 JP 5391419B2 JP 2009038461 A JP2009038461 A JP 2009038461A JP 2009038461 A JP2009038461 A JP 2009038461A JP 5391419 B2 JP5391419 B2 JP 5391419B2
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JP2010193403A (en
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一人 矢野
眞 太郎丸
正純 上羽
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株式会社国際電気通信基礎技術研究所
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  The present invention relates to a radio apparatus and a radio communication system including the radio apparatus, and more particularly to a radio apparatus capable of effectively using radio resources and a radio communication system including the radio apparatus.

  In recent years, cognitive radio has attracted attention as a method for effectively using tight frequency resources (Non-patent Document 1).

  Cognitive radio is roughly classified into a heterogeneous type (Non-Patent Document 2) and a frequency sharing type (Non-Patent Document 3). In the heterogeneous type, the cognitive radio recognizes a plurality of radio systems operating in the vicinity, obtains information on the usage and feasible transmission quality of each system, and connects to an appropriate radio system. In other words, the heterogeneous cognitive radio indirectly increases the utilization efficiency of frequency resources by increasing the utilization efficiency of wireless systems existing in the vicinity.

  On the other hand, in the frequency sharing type, the cognitive radio has a frequency resource (this is called white space) that is not used temporarily or locally in a frequency band in which another radio system is operated. Is detected and signal transmission is performed using this. That is, the frequency sharing type cognitive radio directly increases the utilization efficiency of frequency resources in a certain frequency band.

  In a wireless communication environment where various wireless systems coexist and coexist, such as an unlicensed band, particularly an ISM band (Industry Science Medical band), it is important to effectively use frequency resources.

  When a wireless system is operated in an autonomous and distributed manner, white space is generated discretely on the frequency axis, and its position changes from moment to moment. Under such circumstances, in order to efficiently use the white space, it is possible to accurately grasp the usage status of frequency resources that change with time, select an appropriate transmission frequency (frequency channel), and perform data transmission. Dynamic spectrum access (DSA: Dynamic Spectrum Access) is required (Non-patent Document 4).

S. Haykin, "Cognitive radio: brain-empowered wireless communications," IEEE J. Sol. Areas Commun., Vol. 23, no. 2, pp. 201-220, Feb. 2005. M. Inoue, K. Mahmud, H. Murakami, M. Hasegawa, and H. Morikawa, "Novel out-of-band signaling for seamless interworking between heterogeneous networks," IEEE Wireless Commun., Vol. 11, no. 2, pp. 56-63, April 2004. Sakaguchi Kei, Fujii Takeo, Ono Fumie, Umebayashi Kenta, "Cognitive MIMO Mesh Network-Fundamental Study for Spatial Frequency Sharing Using MIMO Technology," IEICE Technical Report, SR2006-43, pp. 11-18, Nov. 2006. Q. Zhao and B.M. Sadler, "A survey of dynamic spectrum access," IEEE Signal Processing Mag., Vol. 24, no. 3, pp. 79-89, May 2007.

  However, when the DSA system is applied in the ISM band, it is necessary to avoid the occurrence of a collision due to the introduction of the DSA system from the viewpoint of the frequency utilization efficiency of the entire band, that is, a decrease in the throughput of other systems. Therefore, when the DSA system is applied to the ISM band, how to avoid interference with other radio systems becomes a problem.

  It is also important to ensure transmission opportunities for the DSA system itself. In general, a DSA system performs information transmission using a white space in a band. For this reason, it is necessary to exchange information on the channel used between the transmitting and receiving nodes in advance in order to achieve both the reliability of signal transmission and the ease of reception processing.

  In the ISM band in which various wireless systems are operated independently, the white space changes from moment to moment. Therefore, in order to improve the temporal utilization efficiency of frequency resources in the DSA system, it is about several ms at most. It is essential to dynamically and appropriately select a use channel with a fine cycle and to share the information as needed.

  However, since there is no frequency channel that the DSA system can occupy in the ISM band, there is a problem that it is difficult to efficiently share channel selection information between transmitting and receiving nodes.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a radio apparatus capable of efficiently sharing channel selection information while avoiding interference with other radio systems. It is.

  Another object of the present invention is to provide a wireless communication system including a wireless device capable of efficiently sharing channel selection information while avoiding interference with other wireless systems.

  According to the present invention, a radio apparatus is a radio apparatus used in a radio communication environment in which a plurality of cells each managed by a single base station exist and a plurality of different radio systems are mixed. Means, transmitting means, and receiving means. The selection means periodically selects a common control channel from a frequency band used by a plurality of wireless systems by a frequency hopping method. The transmission means performs carrier sense on the common control channel selected by the selection means based on the received signal strength information in the frequency band, and the common control channel selected when the selected common control channel is unused Is used to periodically transmit data channel selection information for selecting a data channel used for data communication. The receiving means measures the received signal strength in the frequency band, generates received signal strength information related to the selected common control channel, outputs the generated received signal strength information to the transmitting means, and is managed by the wireless device The mobile terminal existing in the cell to be used periodically receives the data channel used for data communication determined using the data channel selection information from the mobile terminal.

  Preferably, the transmission means transmits the data channel selection information using a time division method in units of time frames.

  Preferably, when the selected common control channel is used, the transmission unit stops transmitting the data channel selection information in the time frame, and in the next time frame, the transmission unit selects the common channel selected by the frequency hopping method. Attempts to transmit data channel selection information using the control channel.

  Preferably, the selection unit holds a hopping table indicating a hopping pattern of the common control channel in advance, and selects the common control channel for each time frame with reference to the hopping table.

Preferably, the total number of common control channels is N (N is an integer of 2 or more), and the number of wireless devices having mutually different channels that can be received simultaneously is G (G is an integer of 2 or more). Assuming that the number of channels that can be received simultaneously is B 1 to B G , the hopping table uses all the channels once within one period, and uses different channels for each hopping pattern at each time. and it is divided into N common control channel in numerical order B G-1 or by (N / B G-1) number of primary channel block, hopping pattern using each primary channel block alternately, N types of hopping patterns is divided into B G-1 type by (N / B G-1) number of primary pattern group in numerical order, patterns belonging to the same primary pattern group Emissions can use the channels belonging to the same primary channel block at each time point, g (g = 1~G-2 ) B G-g-1 B G-g -number of channels constituting the next channel block in numerical order pieces by (N / B G-g- 1) pieces of (g + 1) is divided into the following channel block, B hopping pattern using each (g + 1) next channel block alternately, constituting each g following pattern group G -g types of hopping patterns is divided into B G-g-1 type by (N / B G-g- 1) pieces of (g + 1) following the pattern group in numerical order, the same (g + 1) pattern which belongs to the next pattern group The structure uses a channel belonging to the same (g + 1) -order channel block at each time point.

  According to the present invention, the radio communication system is a radio communication system used in a radio communication environment in which a plurality of cells each managed by one base station exist and a plurality of different radio systems are mixed. A first and second radio apparatus are provided. The second wireless device performs wireless communication with the first wireless device. Then, the first wireless device periodically selects a common control channel from a frequency band used by a plurality of wireless systems by a frequency hopping method, performs carrier sense on the selected common control channel, and selects the common control channel. When the common control channel is not used, first data channel selection information for selecting a data channel used for data communication using the selected common control channel is periodically transmitted to the second radio apparatus. At the same time, the data channel used for data communication determined by the second radio apparatus using the first data channel selection information is periodically received from the second radio apparatus. Further, the second radio apparatus periodically receives the first data channel selection information from the first radio apparatus, the received first data channel selection information, and the usable data channel observed by itself. The data channel to be used for data communication is periodically determined using the second data channel selection information indicating, and the determined data channel is periodically transmitted to the first wireless device using the common control channel. To do.

  Preferably, the first and second wireless devices transmit and receive data frames to each other in a time division manner using a data channel.

  Preferably, the second radio apparatus receives third data channel selection information for selecting a data channel used for data communication from a third radio apparatus belonging to a cell other than the cell to which the second radio apparatus belongs, The data channel is determined using the first to third data channel selection information.

  Preferably, the second radio apparatus determines a data channel while avoiding a collision with a channel used in a cell other than the cell to which the second radio apparatus belongs.

  The radio apparatus according to the present invention periodically selects a common control channel used for transmission / reception of control information by a frequency hopping method, and uses the selected common control channel when the selected common control channel is unused. The data channel selection information for selecting the data channel used for data communication is periodically exchanged with the mobile terminal in the cell managed by itself.

  Therefore, according to the present invention, channel selection information can be efficiently shared while avoiding interference with other wireless systems.

1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. It is a block diagram of the access point shown in FIG. It is a block diagram of the mobile terminal shown in FIG. It is a block diagram of the channel in embodiment of this invention. It is a block diagram of the time frame of a common control channel. It is a block diagram of a control information frame. It is a figure which shows the hopping pattern of a common control channel. It is a figure for demonstrating the method of sharing the data channel used for communication of a data frame between an access point and a mobile terminal. It is a block diagram of the channel in the first frequency sub-block. 6 is a flowchart for explaining operations of an access point and a mobile terminal belonging to one cell of the wireless communication system. It is a figure which shows the hopping pattern represented by Formula (3).

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

  FIG. 1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. A wireless communication system 100 according to an embodiment of the present invention includes access points (AP: Access Point) 1 to i (i is an integer of 2 or more) and mobile terminals (MS: Mobile Station) 11 to 1i.

  The access point 1 and the mobile terminal 11 are arranged in the cell C1. The access point 2 and the mobile terminal 12 are arranged in the cell C2. Hereinafter, similarly, the access point i and the mobile terminal 1i are arranged in the cell Ci.

  Although not shown in FIG. 1, there are an access point and a mobile terminal that perform wireless communication by a CSMA / CA (Carrier Sense Multiple Access Collision Avidance) method, and an FH-SS (Frequency-Hopping Spread Spread). There are also access points and mobile terminals that perform wireless communication according to a method.

  Therefore, the access points 1 to i and the mobile terminals 11 to 1 i can be used in a wireless communication environment in which a plurality of wireless systems such as a CSMA / CA wireless system and an FH-SS wireless system coexist and coexist. The frequency resource usage state that changes with time is accurately grasped, and an appropriate transmission frequency (frequency channel) is selected to transmit data within each cell C1 to Ci. That is, the access points 1 to i and the mobile terminals 11 to 1 i transmit data in the cells C 1 to Ci by the DSA system.

  In FIG. 1, only one access point and one mobile terminal are shown in each cell C1 to Ci, but actually, each cell C1 to Ci includes a plurality of cells. There is a mobile terminal.

  FIG. 2 is a block diagram of the access point 1 shown in FIG. The access point 1 includes an antenna 101, a transmission unit 102, a reception unit 103, a selection unit 104, a hopping table 105, and a synchronization establishment unit 106.

  The antenna 101 receives a control information frame or data frame from the mobile terminal 11 and outputs the received control information frame or data frame to the receiving means 103. The antenna 101 receives a control information frame or data frame from the transmission unit 102 and transmits the received control information frame or data frame to the mobile terminal 11.

  Transmitting means 102 operates in synchronization with the clock received from synchronization establishing means 106. Then, when the access point 1 is powered on, the transmitting unit 102 receives received signal strength information from the receiving unit 103 for each of 80 channels CH1 to CH80 described later, and based on the received received signal strength information. Carrier sense is performed, and the result of the carrier sense is held and output to the selection means 104. Thereafter, the transmission means 102 always receives the received signal strength information from the receiving means 103, performs carrier sense in each of the channels CH1 to CH80 based on the received received signal strength information, and determines the usage status of each channel CH1 to CH80. Detect and hold.

  Further, the transmission unit 102 receives a common control channel used for transmission of the control information frame from the selection unit 104 in units of time frames to be described later. This control information frame is a frame including data channel selection information indicating a data channel used by the mobile terminal 11 for data communication. Then, the transmission means 102 performs carrier sense on the common control channel based on the received signal strength information received from the reception means 103, and if the common control channel is not used by another access point or mobile terminal, the data channel selection A control information frame including information is generated, and the generated control information frame is transmitted to the mobile terminal 11 in a time division manner within the time frame. That is, the transmission means 102 transmits a control information frame to the mobile terminal 11 by the CSMA / CA method and the TDMA (Time Division Multiple Access) method.

  On the other hand, when the common control channel is used by another access point or a mobile terminal, the transmission unit 102 stops transmission of the control information frame to the mobile terminal 11 and transmits the control information frame within the next time frame. Attempt transmission to the mobile terminal 11.

  Further, the transmission means 102 receives from the reception means 103 a data channel that the mobile terminal 11 is scheduled to use for data communication. Then, the transmission unit 102 generates a data frame, performs carrier sense on the data channel received from the reception unit 103 based on the received signal strength information received from the reception unit 103, and uses an unused data channel. The data frame is transmitted to the mobile terminal 11 in a time division manner.

  The receiving means 103 constantly measures the received signal strength information regarding each of the 80 channels CH1 to CH80 via the antenna 101, and outputs the received signal strength information to the transmitting means 102. The receiving unit 103 receives a control information frame or a data frame from the antenna 101. Then, the receiving means 103 extracts the data channel that the mobile terminal 11 is scheduled to use for data communication from the control information frame, and outputs the extracted data channel to the transmitting means 102.

  The receiving unit 103 receives a data frame from the mobile terminal 11 via the antenna 101 and outputs the received data frame to the transmitting unit 102.

  The selection unit 104 operates in synchronization with the clock received from the synchronization establishment unit 106. Then, the selection unit 104 receives the result of carrier sense in each of the channels CH1 to CH80 from the transmission unit 102, and based on the received carrier sense result, common control with a high ratio used by other access points is performed. A group of channels is selected, and any one common control channel included in the selected group is selected as the initial common control channel.

  Thereafter, the selection unit 104 refers to the hopping table 105 for each time frame, hops the initial common control channel, and outputs the hopped common control channel to the transmission unit 102.

  Furthermore, after that, the selection unit 104 refers to the hopping table 105 in the next time frame, hops the common control channel, and outputs the hopped common control channel to the transmission unit 102.

  The hopping table 105 stores the hopping pattern of the common control channel. The synchronization establishment means 106 receives a GPS signal from, for example, a GPS (Global Positioning System) satellite (not shown), and generates a clock based on the received GPS signal. Then, the synchronization establishment unit 106 outputs the generated clock to the transmission unit 102 and the selection unit 104.

  Each of the access points 2 to i shown in FIG. 1 has the same configuration as that of the access point 1 shown in FIG.

  FIG. 3 is a block diagram of the mobile terminal 11 shown in FIG. The mobile terminal 11 includes an antenna 111, a transmission unit 112, a reception unit 113, a channel determination unit 114, and a synchronization establishment unit 115.

  Antenna 111 receives a control information frame including data channel selection information from access point 1 and an access point other than access point 1, and outputs the received control information frame to receiving means 113. Further, the antenna 111 receives a control information frame or data frame from the transmission unit 112 and transmits the received control information frame or data frame to the access point 1.

  The transmission unit 112 operates in synchronization with the clock received from the synchronization establishment unit 115. Then, the transmission means 112 receives the received signal strength information from the receiving means 113, performs carrier sense on each of the channels CH1 to CH80 based on the received received signal strength, holds the result of the carrier sense, and determines the channel. To 114.

  The transmission unit 112 receives a data channel used by the mobile terminal 11 for data communication from the channel determination unit 114, and receives a common control channel used by the access point 1 for transmission of the control information frame from the reception unit 113.

  Then, the transmission means 112 generates a control information frame including data channel selection information indicating the received data channel, and transmits the generated control information frame to the access point 1 through the common control channel.

  Further, the transmission means 112 generates a data frame. Then, the transmission unit 112 performs carrier sense on the data channel scheduled to be used for data communication based on the received signal strength information received from the reception unit 113, and uses the unused data channel to generate the generated data frame. Is transmitted to the access point 1 in a time division manner.

  The receiving means 113 constantly measures the received signal strength information regarding each of the 80 channels CH1 to CH80 via the antenna 111, and outputs the received signal strength information to the transmitting means 112.

  The receiving means 113 detects the arrival of a frame via the antenna 111 with the number of channels that can be simultaneously received by the mobile terminal 11 (that is, the reception bandwidth of the mobile terminal 11). A control information frame including data channel selection information is received from the access point, and the channel when the control information frame is received is detected as a common control channel. The receiving unit 113 outputs the detected common control channel to the transmitting unit 112 and outputs the received control information frame to the channel determining unit 114.

  Further, the reception unit 113 detects arrival of a frame with the reception bandwidth of the mobile terminal 11, receives a data frame, and outputs the received data frame to the transmission unit 112.

  Channel determining means 114 operates in synchronization with the clock received from synchronization establishing means 115. Then, the channel determination unit 114 receives the control information frame including the data channel selection information from the reception unit 103 and receives the result of carrier sense in each of the channels CH1 to CH80 from the transmission unit 112. Then, the channel determination means 114 determines the data channel that the mobile terminal 11 uses for data communication based on the data channel selection information and the result of carrier sense in each of the channels CH1 to CH80, and transmits the determined data channel. To 112.

  The synchronization establishment unit 115 generates a clock by the same method as the synchronization establishment unit 106 described above, and outputs the generated clock to the transmission unit 112 and the channel determination unit 114.

  Note that each of the mobile terminals 12 to 1i shown in FIG. 1 has the same configuration as the mobile terminal 11 shown in FIG.

  FIG. 4 is a configuration diagram of channels in the embodiment of the present invention. In the embodiment of the present invention, a frequency band of 2402 MHz to 2481 MHz is used. Channels CH1 to CH80 each have a center frequency of 2402 MHz to 2481 MHz and have a signal bandwidth of 1 MHz.

  The common control channels CCH1 to CCH16 are composed of 16 channels whose channel numbers end with “1” or “6”. These frequencies are the same as the transmission frequencies used by the IEEE802.11 wireless LAN (Local Area Network) operated in the frequency band (except for the frequencies of the common control channels CCH1, CCH2, and CCH16). .

  Of the 80 channels CH1 to CH80, 16 common control channels CCH1 to CCH16 are preferentially used for transmission of control information frames, and the remaining 64 channels are used for transmission of data frames.

  Note that the common control channel that is not used for transmission of the control information frame can be temporarily used for transmission of the data frame.

  FIG. 5 is a configuration diagram of a time frame of the common control channel. The time frame has a length of 5 ms. The time frame includes a sensing period, four downlinks DL1 to DL4, and four uplinks UL1 to UL4.

  Each of the four downlinks DL1 to DL4 and the four uplinks UL1 to UL4 constitutes a slot.

  The sensing period has a length of 200 μs, and each of the four downlinks DL1 to DL4 and the four uplinks UL1 to UL4 has a length of 600 μs.

The length of the sensing period is set to 200 μs for the following reason. In ERP-OFDM of IEEE802.11a or IEEE802.11g, the sensing period is longer than 169 μs which is the maximum waiting time (DIFS + contention slot length × CW min ) required to start transmission of the first data frame This is to prevent the transmission opportunity of the wireless LAN sharing the same frequency band as the DSA system as much as possible by increasing the length.

  The sensing period is used for observing the usage status of each frequency channel CH1 to CH80.

  Each of the four downlinks DL1 to DL4 and the four uplinks UL1 to UL4 is used for transmission of control information.

  More specifically, the three uplink UL1 to UL3 and the three downlink DL1 to DL3 specify the data transmission node and the reception node in the next time frame and the selection of the frequency channel used at that time. Used for information exchange.

  In this case, each of the cells C1 to Ci selects and uses a slot having the same number on the same common control channel in both the uplink and the downlink. Therefore, a maximum of 48 cells (= 16 × 3) can be operated simultaneously in the vicinity.

  Each of the cells C1 to Ci changes the common control channel used for each time frame in accordance with a hopping pattern described later, and increments the slot number to be used at the same time. By averaging the probability of occurrence of interference in the frequency direction and the time direction, even when some frequency channels are occupied by other radio systems, the fairness of transmission opportunities of control information between cells This is to ensure

  UL4, which is the fourth uplink slot, is used for control information other than channel selection information indicating a channel selected for data transmission (for example, location registration request from mobile terminal to access point and connection establishment request). Used for transmission.

  The multiple access in this case is random access in each of the cells C1 to Ci using the same common control channel.

  DL4, which is the fourth slot of the downlink, constitutes a super time frame by a plurality of (about 20 to 30) time frames, and is used for transmission such as a broadcast channel, location registration confirmation, paging and connection establishment confirmation. It is done. At this time, multiple access between cells using the same common control channel is performed by TDMA in units of time frames.

  FIG. 6 is a configuration diagram of a control information frame. The control information frame CTLF has a length of 544 μs and includes a preamble, a physical header, and data.

  The preamble has a length of 204.8 μs and is set at the head of the control information frame CTLF. The physical header has a length of 41.6 μs and is set following the preamble. The data has a length of 297.6 μs and is set at the end of the control information frame CTLF following the physical header.

  The guard time 1 has a length of 24 μs and is set before the control information frame CTLF. The guard time 2 has a length of 32 μs and is set after the control information frame CTLF.

  The total length of the guard times 1 and 2 and the control information frame CTLF is set to 600 μs which is equal to the length of one slot.

  The preamble is composed of eight short preambles SP (short preamble) and two long preambles (long preamble).

  Each of the eight short preambles SP has a length of 8 symbols, and each of the two long preambles has a length of 32 symbols. As a result, the preamble has a length of 128 symbols (= 204.8 μs).

  The short preamble SP is used for automatic gain control AGC (Auto Gain Control) adjustment and frequency offset compensation. Note that the maximum allowable frequency offset in this format is set to 7.8 ppm.

  The long preamble is used for residual frequency offset compensation, reception timing synchronization, and propagation path estimation.

  The physical header includes a rate, a reservation, a length, a parity, and a tail. The rate has a length of 6 bits, the reservation has a length of 1 bit, the length has a length of 12 bits, the parity has a length of 1 bit, Has a length of 6 bits. As a result, the physical header has a length of 26 symbols (= 41.6 μs).

  The rate indicates a modulation scheme, a coding rate, and the number of transmission antennas. The length indicates the length of the data portion with the symbol length (= 1.6 μs) as a unit. In the tail, “0”, which is a known bit, is set.

  The reason why the length has a length of 12 bits is that the length of 12 bits is the minimum number of bits necessary for expressing the length of the time frame (= 5 ms).

  The data includes a service, a type, a subtype, an AP-ID, a Tx-ID, an Rx-ID, a Tx-BW, an Rx-BW, a map, a CRC, and a tail.

  The service has a length of 16 bits, the type has a length of 8 bits, the subtype has a length of 8 bits, and the AP-ID has a length of 16 bits.

  Each of Tx-ID and Rx-ID has a length of 8 bits. Each of Tx-BW and Rx-BW has a length of 2 bits. The map has a length of 80 bits, the CRC has a length of 32 bits, and the tail has a length of 6 bits.

  As a result, the data has a length of 186 symbols (= 297.6 μs).

  The service consists of a descrambling sequence and spare bits. The type and subtype specify the frame type. AP-ID indicates the number of a base station (cell). Tx-ID indicates the intra-cell ID of the transmission node. Rx-ID indicates the intra-cell ID of the receiving node.

  Tx-BW indicates the reception bandwidth of the transmission node. Rx-BW indicates the reception bandwidth of the reception node. The map indicates the selection status of the used frequency channel. CRC consists of CRC-32 parity bits. The tail consists of a channel decoder trellis termination sequence.

  The map has a structure in which “1” or “0” is stored in association with channels CH1 to CH80. “1” indicates that the corresponding channel is used, and “0” indicates that the corresponding channel is unused.

  FIG. 7 is a diagram showing a hopping pattern of the common control channel. In the radio communication system 100, synchronization is maintained between the cells C1 to Ci. Therefore, all hopping patterns of the common control channel are designed so that no collision occurs with each other.

  In the radio communication system 100 using the DSA system, dynamic channel selection is simultaneously performed in a plurality of cells during data transmission. Therefore, it is desirable that the common control channels used in the cells located in the vicinity are close on the frequency axis from the viewpoint of sharing information between cells.

Therefore, the hopping pattern f hop (n, j) (n and j are positive integers) of the common control channel in the wireless communication system 100 is expressed by the following equation.

  In formula (1), [x] represents the maximum integer not exceeding x.

  FIG. 7 shows the hopping pattern represented by the expression (1).

  The type and period of the hopping pattern is “16”, which is the same as the number of common control channels, and each hopping pattern uses all the common control channels once in one period.

  The 16 common control channels are divided into two frequency blocks 1 and 2. The frequency block 1 is divided into two frequency sub-blocks 1 and 2, and the frequency block 2 is divided into two frequency sub-blocks 3 and 4.

  When the common control channel to be used is hopped based on the hopping pattern, the two frequency blocks 1 and 2 are used alternately, the two frequency subblocks 1 and 2 are used alternately, and the two frequency subblocks 3 , 4 are used alternately.

For example, taking the case of using the first hopping pattern f hop (1, j) as an example, the selected common control channel CCH is transmitted to the frequency sub-block 1 of the frequency block 1 in the first hop (j = 1). belong to. The common control channel CCH selected at the second hop belongs to the frequency sub-block 3 of the frequency block 2, and the frequency sub-block 2 of the frequency block 1 at the third hop and the frequency at the fourth hop. Each belongs to the frequency sub-block 4 of the block 2.

  As a result, as the common control channel CCH to be used, the frequency blocks 1 and 2 are alternately selected, the frequency sub-blocks 1 and 2 are alternately selected in the frequency block 1, and the frequency sub-block in the frequency block 2. Hopping is performed so that 3 and 4 are alternately selected.

The same applies to the case of using other hopping patterns f hop (2, j) to f hop (16, j).

  In Expression (1), the first term on the right side represents selection of frequency blocks 1 and 2, the second term on the right side represents selection of frequency sub-blocks 1 and 2 and frequency sub-blocks 3 and 4, and the third term on the right side. Represents a position in the frequency sub-blocks 1 to 4.

When the common control channel CCH to be used is selected based on the first hopping pattern f hop (1, j), the common control channel CCH1 is selected at the first hop. The common control channel CCH1 exists at the first position in the frequency sub-block 1 of the frequency block 1. In the second hop, the first position in the frequency sub-block 3 of the frequency block 2 is selected. Since the first position in the frequency sub-block 3 is the position of the common control channel CCH9, the common control channel CCH to be used is hopped to the common control channel CCH9 at the second hop.

  Similarly, the common control channel CCH to be used is hopped to the common control channel CCH5 at the third hop, hopped to the common control channel CCH13 at the fourth hop, and then to the common control channel CCH2 at the fifth hop. Hopping, hopping to common control channel CCH10 at the 6th hop, hopping to common control channel CCH6 at the 7th hop, hopping to common control channel CCH14 at the 8th hop, common control channel at the 9th hop Hop to CCH3, hop to common control channel CCH11 at 10th hop, hop to common control channel CCH7 at 11th hop, hop to common control channel CCH15 at 12th hop, common at 13th hop Hop to control channel CCH4 Hopping to the common control channel CCH12 4 th hop, hop to the common control channel CCH8 at the 15 th hop, hop to the common control channel CCH16 at the 16 th hop.

  Thereafter, the first to 16th hops are repeatedly executed.

  As a result, the common control channel CCH to be used is hopped to all of the 16 common control channels CCH1 to CCH16 in one cycle (from the first hop to the 16th hop).

The same applies to the case of using other hopping patterns f hop (2, j) to f hop (16, j).

  In the hopping pattern, four common control channels are grouped in numerical order, and each group uses a single frequency sub-block at each time.

  Further, the hopping pattern is also divided into four blocks in the time direction, and each time block corresponds to one obtained by cyclically shifting each other in the frequency sub-block. That is, the hopping patterns belonging to the same group are in a cyclic shift relationship with each other.

  Further, the number of common control channels belonging to each of the frequency sub-blocks 1 to 4 is determined according to the narrowest reception bandwidth among the reception bandwidths of the access points 1 to i and the mobile terminals 11 to 1 i. The number of common control channels belonging to each of frequency blocks 1 and 2 is determined according to the second narrowest reception bandwidth among the reception bandwidths of access points 1 to i and mobile terminals 11 to 1 i. The number of common control channels belonging to each of the frequency blocks 1 and 2 is an integral multiple of the number of common control channels belonging to each of the frequency sub-blocks 1 to 4. The number of channels is an integral multiple of the number of common control channels belonging to each of the frequency blocks 1 and 2.

  In the hopping pattern shown in FIG. 7, the number of common control channels belonging to each of the frequency sub-blocks 1 to 4 is determined to be four according to the reception bandwidth of 20 MHz, and the common control channel belonging to each of the frequency blocks 1 and 2 is determined. Is determined to be 8 according to the reception bandwidth of 40 MHz. The number of common control channels (= 8) belonging to each of frequency blocks 1 and 2 is twice the number of common control channels (= 4) belonging to each of frequency sub-blocks 1 to 4. The number of common control channels (= 16) belonging to the entire blocks 1 and 2 is twice the number of common control channels (= 8) belonging to each of the frequency blocks 1 and 2.

  Due to the characteristics of the hopping pattern described above, control information for cells using hopping patterns belonging to the same group can all be received simultaneously using a radio apparatus having a reception bandwidth of 20 MHz or more. This is because the frequency bandwidth in which four common control channels belonging to one group exist is 20 MHz.

  Therefore, if the hopping patterns of neighboring cells are set to belong to the same group, control information can be shared between different cells relatively easily. In addition, the inhibition of backoff processing of other wireless systems located in the vicinity is reduced, and a decrease in throughput of these systems can be suppressed.

  In the wireless communication system 100, the access points 1 to i and the mobile terminals 11 to 1i have different reception bandwidths, but have a reception bandwidth of at least 20 MHz. In FIG. 1, common control channels belonging to the same group of hopping patterns are set in the adjacent cells C1 to C3 and the cells Ci-1, Ci and the like.

  In each of the access points 1 to i, the hopping table 105 holds the hopping pattern shown in FIG. Therefore, in each of the access points 1 to i, the selection unit 104 selects a common control channel to be used in each time frame with reference to the hopping pattern shown in FIG.

  FIG. 8 is a diagram for explaining a method of sharing a data channel used for data frame communication between the access points 1 to i and the mobile terminals 11 to 1 i. In FIG. 8, a method of sharing a data channel used for data frame communication between the access point 1 belonging to the cell C1 and the mobile terminal 11 will be described.

  The selection unit 104 of the access point 1 receives the result of carrier sense in each of the channels CH1 to CH80 from the transmission unit 102, and based on the received result of carrier sense, the other access points 2 and 3 by the method described above. Frequency sub-block 1 is selected as a group having a high ratio of being used.

  Then, the selection means 104 of the access point 1 selects the common control channel CCH1 belonging to the selected frequency subblock 1 as the initial common control channel CCH_ini used by the access point 1. That is, the selection means 104 of the access point 1 selects the common control channel CCH1 at the first hop.

  The transmission means 102 of the access point 1 receives the common control channel CCH1 from the selection means 104, and performs carrier sense on the common control channel CCH1 based on the received signal strength information received from the reception means 103 in the sensing period 1.

  If the common control channel CCH1 is unused as a result of carrier sense, the transmission means 102 of the access point 1 uses a map (= data channel selection information) indicating the usage status for the channels CH1 to CH80 as “1” or “0”. ), And the generated control information frame CTLF1 is transmitted to the mobile terminal 11 in the slot (= DL1) of the time frame TF1 using the common control channel CCH1.

  Then, the reception means 113 of the mobile terminal 11 detects the arrival of a frame in the frequency band (= 2402 to 2481 MHz) of the common control channels CCH1 to CCH16 via the antenna 111, and receives the control information frame CTLF1 on the common control channel CCH1. Then, the received control information frame CTLF1 is output to the channel determining means 114, and the common control channel CCH1 that has received the control information frame CTLF1 is output to the transmitting means 112.

  Thereafter, the channel determination unit 114 of the mobile terminal 11 receives the control information frame CTLF1 from the reception unit 113, refers to the map of the received control information frame CTLF1, and uses the channels CH1 to CH80 observed by the access point 1 To get. Further, the channel determination unit 114 of the mobile terminal 11 receives from the transmission unit 112 the usage status of the channels CH1 to CH80 observed by the transmission unit 112.

  Then, the channel determination unit 114 of the mobile terminal 11 starts from the channels CH1 to CH80 based on the usage status of the channels CH1 to CH80 received from the access point 1 and the usage status of the channels CH1 to CH80 received from the transmission unit 112. Of the 64 channels excluding the common control channels CCH1 to CCH16, an unused channel is determined as the data channel DCH_1 used by the mobile terminal 11 for data frame communication. Then, the channel determination unit 114 of the mobile terminal 11 outputs the determined data channel DCH_1 to the transmission unit 112.

  Thereafter, the transmission means 112 of the mobile terminal 11 receives the data channel DCH_1 from the channel determination means 114 and the common control channel CCH1 from the reception means 113. Then, the transmission means 112 of the mobile terminal 11 generates a control information frame CTLF2 including the data channel DCH_1, and accesses the generated control information frame CTLF2 in the slot (= UL1) of the time frame TF1 using the common control channel CCH1. Send to point 1.

  The receiving means 103 of the access point 1 detects the arrival of a frame via the antenna 101, receives the control information frame CTLF2 through the common control channel CCH1, and outputs the received control information frame CTLF2 to the transmitting means 102.

  Then, the transmission means 102 of the access point 1 detects the data channel DCH_1 included in the control information frame CTLF2 received from the reception means 103, and the data channel used by the mobile terminal 11 for data frame communication is the data channel DCH_1. Detect that.

  As a result, the data channel DCH_1 is shared between the access point 1 and the mobile terminal 11.

  After that, the access point 1 and the mobile terminal 11 select an unused channel at the time of data frame transmission from the data channel DCH_1 by carrier sense, and transmit and receive the data frame DTF1 to each other in a time division manner using the selected channel. To do.

  Note that the reception means 113 of the mobile terminal 11 detects the arrival of a frame in the frequency band (= 2402 to 2481 MHz) of the common control channels CCH1 to CCH16 via the antenna 111. As a result, not only the control information frame CTLF1, When the control information frame CTLF3 from the access point 2 belonging to the cell C2 is received, the control information frame CTLF1 and the control information frame CTLF3 are output to the channel determining means 114.

  Then, the channel determination means 114 of the mobile terminal 11 receives from the transmission means 112 the usage status of the channels CH1 to CH80 included in the control information frame CTLF1, the usage status of the channels CH1 to CH80 included in the control information frame CTLF3, and Based on the usage status of channels CH1 to CH80, data channel DCH_1 is determined by the method described above.

  Thereby, the data channel DCH_1 can be determined from an unused channel in the cell C2 adjacent to the cell C1, and interference between the cells C1 and C2 can be avoided.

  On the other hand, if the common control channel CCH1 is in use as a result of carrier sense on the common control channel CCH1 in the sensing period 1, the transmission means 102 of the access point 1 stops transmission of the control information frame CTLF in the time frame TF1. .

  After the time frame TF1 is completed, when the selecting unit 104 of the access point 1 detects the time frame TF2 in synchronization with the clock from the synchronization establishing unit 106, the hopping pattern stored in the hopping table 105 (see FIG. 7) is referred to. Then, the common control channel CCH9 is selected as the common control channel used in the time frame TF2. That is, the common control channel to be used is hopped from the common control channel CCH1 to the common control channel CCH9. Then, the selection means 104 of the access point 1 outputs the selected common control channel CCH9 to the transmission means 102.

  In this case, the selecting unit 104 of the access point 1 selects the common control channel CCH9 in the same manner even when the transmitting unit 102 does not transmit the control information frame CTLF to the mobile terminal 11 in the time frame TF1, and transmits the same. Output to.

  The transmission means 102 of the access point 1 receives the common control channel CCH9 from the selection means 104, and performs carrier sense on the common control channel CCH9 based on the received signal strength information received from the reception means 103 in the sensing period 2. Then, if the common control channel CCH9 is not used, the transmission means 102 of the access point 1 includes a map (= data channel selection information) indicating the usage status for the channels CH1 to CH80 as “1” or “0”. A control information frame CTLF4 is generated, and the generated control information frame CTLF4 is transmitted to the mobile terminal 11 in the slot (= DL2) of the time frame TF2 using the common control channel CCH9.

  Then, the reception means 113 of the mobile terminal 11 detects the arrival of a frame in the frequency band (= 2402 to 2481 MHz) of the common control channels CCH1 to CCH16 via the antenna 111, and receives the control information frame CTLF4 on the common control channel CCH9. Then, the received control information frame CTLF4 is output to the channel determining means 114, and the common control channel CCH9 receiving the control information frame CTLF4 is output to the transmitting means 112.

  Thereafter, the channel determination unit 114 of the mobile terminal 11 receives the control information frame CTLF4 from the reception unit 113, refers to the map of the received control information frame CTLF4, and uses the channels CH1 to CH80 observed by the access point 1 To get. Further, the channel determination unit 114 of the mobile terminal 11 receives from the transmission unit 112 the usage status of the channels CH1 to CH80 observed by the transmission unit 112.

  Then, the channel determination unit 114 of the mobile terminal 11 starts from the channels CH1 to CH80 based on the usage status of the channels CH1 to CH80 received from the access point 1 and the usage status of the channels CH1 to CH80 received from the transmission unit 112. Of the 64 channels excluding the common control channels CCH1 to CCH16, an unused channel is determined as the data channel DCH_2 used by the mobile terminal 11 for data frame communication. Then, the channel determination unit 114 of the mobile terminal 11 outputs the determined data channel DCH_2 to the transmission unit 112.

  Thereafter, the transmission means 112 of the mobile terminal 11 receives the data channel DCH_2 from the channel determination means 114 and the common control channel CCH9 from the reception means 113. Then, the transmission means 112 of the mobile terminal 11 generates the control information frame CTLF5 including the data channel DCH_2, and accesses the generated control information frame CTLF5 in the slot (= UL2) of the time frame TF2 using the common control channel CCH9. Send to point 1.

  The receiving means 103 of the access point 1 detects the arrival of a frame via the antenna 101, receives the control information frame CTLF5 through the common control channel CCH9, and outputs the received control information frame CTLF5 to the transmitting means 102.

  Then, the transmission means 102 of the access point 1 detects the data channel DCH_2 included in the control information frame CTLF5 received from the reception means 103, and the data channel used by the mobile terminal 11 for data frame communication is the data channel DCH_2. Detect that.

  As a result, the data channel DCH_2 is shared between the access point 1 and the mobile terminal 11.

  Thereafter, the access point 1 and the mobile terminal 11 select an unused channel during data frame transmission from the data channel DCH_2 by carrier sense, and transmit / receive the data frame DTF2 to / from each other in a time division manner using the selected channel. To do.

  Even in the time frame TF2, the reception unit 113 of the mobile terminal 11 detects the arrival of a frame in the frequency band (= 2402 to 2481 MHz) of the common control channels CCH1 to CCH16 via the antenna 111. As a result, the control information frame When not only the CTLF 5 but also the control information frame CTLF 6 from the access point 2 belonging to another cell C 2 is received, the control information frame CTLF 5 and the control information frame CTLF 6 are output to the channel determining means 114.

  Then, the channel determination unit 114 of the mobile terminal 11 receives from the transmission unit 112 the usage status of the channels CH1 to CH80 included in the control information frame CTLF5, the usage status of the channels CH1 to CH80 included in the control information frame CTLF6, and Based on the usage status of channels CH1 to CH80, data channel DCH_2 is determined by the method described above.

  As a result, the data channel DCH_2 can be determined from an unused channel in the cell C2 adjacent to the cell C1, and interference between the cells C1 and C2 can be avoided even in the time frame TF2.

  On the other hand, if the common control channel CCH9 is in use as a result of carrier sense on the common control channel CCH9 in the sensing period 2, the transmission means 102 of the access point 1 stops transmission of the control information frame CTLF in the time frame TF2. .

  Thereafter, the access point 1 repeatedly executes the above-described operation to change the common control channel CCH according to the hopping pattern (see FIG. 7) for each time frame TF, and uses the changed common control channel CCH to change the channel CH1. Control information frame CTLF including the use status of CH80 is transmitted to mobile terminal 11 in a time division manner. Then, the mobile terminal 11 determines the data channel DCH by the method described above and transmits it to the access point 1 for each time frame TF. Thereby, the access point 1 and the mobile terminal 11 share the data channel DCH for each time frame TF.

  The access points 2 to i and the mobile terminals 12 to 1 i also share the data channel DCH by the same method as the access point 1 and the mobile terminal 11.

  According to the above-described method, the frequency channel to be used is determined in an autonomous and distributed manner in each cell C1 to Ci prior to the transmission of the data frame, and the information is transmitted and received on the common control channel by the transmission / reception nodes (access points 1 to i and mobile Exchanged between terminals 11-1i).

  In this case, in order to realize efficient data frame transmission, it is important how to avoid channel selection contention between cells.

  Therefore, in the embodiment of the present invention, the number of the common control channel, slot number, and hopping pattern used by each cell C1 to Ci for exchanging frequency channel selection information (= map in the control information frame CTLF). Set the channel selection priority based on the number. In this case, the fairness between the cells C1 to Ci and the configuration of the receiving node are considered.

  This will be specifically described below. Of the channels CH1 to CH80, 64 channels excluding the common control channels CCH1 to CCH16 are designated as data channels DCH1 to DCH64 in ascending order of frequency.

  First, the 80 channels CH1 to CH80 are divided into 20 (4 common control channels and 16 data channels), and the first to fourth frequency sub-blocks are set in ascending order of frequency. This is an extension of the frequency sub-block in the common control channel to the data channel.

  FIG. 9 is a configuration diagram of channels in the first frequency sub-block. In the first frequency sub-block, there are four common control channels CCH1 to CCH4 and 16 data channels DCH1 to DCH16.

  The common control channels CCH1 to CCH4 are composed of 2402 MHz, 2407 MHz, 2412 MHz, and 2417 MHz, respectively.

  The data channels DCH1 to DCH16 are composed of 2403 MHz, 2404 MHz, 2405 MHz, 2406 MHz, 2408 MHz, 2409 MHz, 2410 MHz, 2411 MHz, 2413 MHz, 2414 MHz, 2415 MHz, 2416 MHz, 2418 MHz, 2419 MHz, 2420 MHz, and 2421 MHz, respectively.

  Each of the second to fourth frequency sub-blocks has the same configuration as the first frequency sub-block shown in FIG. 9, and after the second frequency sub-block, the channel number is set to 20 for each frequency sub-block. 4 is added to the common control channel number, and 16 is added to the data channel number.

(1) Channel selection priority in the same frequency sub-block The channel selection priority in the same frequency sub-block when selecting a frequency channel during data frame transmission will be described by taking the first frequency sub-block as an example.

  As shown in FIG. 9, there are 16 data channels DCH1 to DCH16 in each frequency sub-block. Among these, twelve data channels DCH1 to DCH12 sandwiched between outer common control channels (CCH1 and CCH4) are twelve cells (4) using the common control channels CCH1 to CCH4 in the frequency subblock. The common control channels CCH1 to CCH4 and 3 slots (DL1, UL1; DL2, UL2; DL3, UL3) are equally distributed preferentially.

  This is because in the wireless communication system 100, the access points 1 to i and the mobile terminals 11 to 1i are designed to be able to simultaneously receive at least four consecutive common control channels, and the Nyquist frequency is 20 MHz. This is because the influence of roll-off of the band limiting filter in the receiver is taken into consideration.

  The four data channels DCH13 to DCH16 positioned outside the common control channel CCH4 are given preferentially to the cells using the common control channels CCH1 to CCH4, respectively.

  When there are a plurality of cells using the same common control channel, the cells are given priority in ascending order of the used slots. In radio communication system 100, since the slot number used for exchanging frequency channel selection information (= map in control information frame CTLF) is incremented in units of time frames, fairness between cells using the same common control channel is obtained. Sex is ensured by this.

  In the wireless communication system 100, an unused common control channel is also used for data frame transmission. In that case, the common control channels CCH1 to CCH4 are preferentially allocated by the same method as the data channels DCH13 to DCH16 described above.

  Table 1 shows the channel selection priorities created based on the above guidelines.

  In Table 1, a-b represents a cell that is using the b-th slot of the a-th common control channel for exchanging frequency channel selection information (= map in the control information frame CTLF). For example, 1-1 represents a cell that is using the first slot (DL1, UL1) of the first common control channel CCH1 for exchanging frequency channel selection information (= map in the control information frame CTLF).

(2) Channel selection priority between different frequency sub-blocks The channel selection priority between different frequency sub-blocks when selecting a frequency channel during data frame transmission will be described.

  As shown in FIG. 7, the radio communication system 100 uses each frequency sub-block in a pattern group unit in which hopping patterns of a plurality of common control channels are bundled. Thus, the preferential selection within the same pattern group (within the frequency sub-block) is given by the method described in (1) above, and the preferential selection of channels between pattern groups (between the frequency sub-blocks) is: The following method is used.

(I) A pattern group that is using the frequency sub-block for exchanging frequency channel selection information at the time of selection of the frequency channel to be used. (Ii) When the data frame is scheduled to be transmitted (next time frame), the frequency channel selection information Pattern group using frequency sub-block (iii) Among pattern groups not corresponding to (i) and (ii) above, a pattern group using a frequency sub-block adjacent to the frequency sub-block (two corresponding patterns) If present, a pattern group with a lower frequency)
(Iv) Pattern group not corresponding to the above (i) to (iii) When the channel to be used is selected at time j = 1 when the pattern group configuration (grouping by 4 in ascending order of pattern number) is performed (time Table 2 shows the selection priority order of frequency channels for each frequency sub-block in (transmission of data frame at j = 2).

  In Table 2, “FSBa” represents the a-th frequency sub-block, and “PGb” represents the b-th pattern group.

  Note that, also in channel selection after time j = 1, the selection priority among the pattern groups is determined based on FIG.

  Therefore, the channel determining means 114 of each of the mobile terminals 11 to 1i preferably determines the data channel DCH according to the above-described Table 1 between cells using channels in the same frequency sub-block, The data channel DCH is determined in accordance with the above-described Table 2 between cells using the channel between blocks.

  FIG. 10 is a flowchart for explaining operations of an access point and a mobile terminal belonging to one cell of the wireless communication system 100.

  In addition, in FIG. 10, operation | movement of the access point 1 and the mobile terminal 11 which belong to the cell C1 is demonstrated.

  When a series of operations is started, the selection unit 104 of the access point 1 selects the initial common control channel CCH_ini by the method described above, and sets the selected common control channel CCH_ini as the common control channel CCH (step S1).

  Then, the access point 1 sets m = 1 (step S2), and outputs the common control channel CCH to the transmission means 102. Thereafter, the transmission means 102 of the access point 1 performs carrier sense on the common control channel CCH based on the received signal strength information received from the reception means 103 during the sensing period of the time frame TF (m) (step S3). It is determined whether or not the channel CCH is in use (step S4).

  When it is determined in step S4 that the common control channel CCH is not in use, the transmission means 102 of the access point 1 uses the three slots (= DL1, UL1; DL2, UL2; DL3, DL) of the time frame TF (m). One arbitrary slot is selected from (UL3) (step S5).

  Thereafter, the transmission means 102 of the access point 1 generates a control information frame CTLF1 including a map indicating the usage status of the channels CH1 to CH80 by the method described above based on the carrier sense result on the channels CH1 to CH80 (step S1). S6).

  Then, the transmission means 102 of the access point 1 transmits the control information frame CTLF1 to the mobile terminal 11 using the common control channel CCH in the selected slot in the time frame TF (m) (step S7).

  Then, the receiving means 113 of the mobile terminal 11 detects the arrival of the frame on the channels CH1 to CH80, and receives the control information frame CTLF1 on the common control channel CCH (step S8).

  Then, the receiving means 113 of the mobile terminal 11 outputs the control information frame CTLF1 to the channel determining means 114 and outputs the common control channel CCH when the control information frame CTLF1 is received to the transmitting means 112.

  Thereafter, the channel determination means 114 of the mobile terminal 11 determines the data channel DCH based on the usage status of the channels CH1 to CH80 extracted from the control information frame CTLF1 and the usage status of the channels CH1 to CH80 observed by the transmission means 112. The determined data channel DCH is output to the transmission means 112 (step S9).

  The transmission means 112 of the mobile terminal 11 receives the data channel DCH from the channel determination means 114 and receives the common control channel CCH from the reception means 113. Then, the transmission means 112 of the mobile terminal 11 generates a control information frame CTLF2 including the data channel DCH (step S10), and selects a slot having the same number as the access point 1 (step S11). For example, if the access point 1 has selected a slot consisting of DL1, the transmission means 112 of the mobile terminal 11 selects a slot consisting of UL1. Since the access points 1 to i and the mobile terminals 11 to 1i are synchronized, the transmission unit 112 of the mobile terminal 11 receives the timing at which the reception unit 113 receives the control information frame CTLF1 (that is, the common control channel CCH ) From the receiving means 113), the slot selected by the access point 1 can be detected.

  After step S11, the transmission means 112 of the mobile terminal 11 transmits the control information frame CTLF2 to the access point 1 using the common control channel CCH in the selected slot (step S12).

  Then, the receiving means 103 of the access point 1 detects the arrival of the frame on the channels CH1 to CH80, receives the control information frame CTLF2 on the common control channel CCH (step S13), and transmits the received control information frame CTLF2 To 102.

  Thereafter, the transmission means 102 of the access point 1 receives the control information frame CTLF2 from the reception means 103, and detects the data channel DCH from the received control information frame CTLF2 (step S14). As a result, the data channel DCH is shared between the access point 1 and the mobile terminal 11.

  Then, the access point 1 and the mobile terminal 11 perform carrier sense on the data channel DCH, and if there is an unused channel in the data channel DCH, generate a data frame and use the unused channel to generate the data frame. Transmission and reception are performed in a time division manner (step S15).

  If all the data channels DCH are in use, the access point 1 and the mobile terminal 11 stop transmitting data frames.

  On the other hand, when it is determined in step S4 that the common control channel CCH is in use, the transmission means 102 of the access point 1 stops transmission of the control information frame CTLF (step S16).

  After step S15 or step S16, the access point 1 sets m = m + 1 (step S17), changes the common control channel according to the hopping pattern in the time frame TF (m), and changes the common control channel CCH_hop after the change. Is set to the common control channel CCH (step S18).

  Thereafter, the series of operations returns to Step S3, and Steps S3 to S18 described above are repeatedly executed.

  When step S5 is executed after the second time, the transmission means 102 of the access point 1 increments the slot number selected last time by one, selects a slot, selects a slot consisting of DL3, and then selects a slot. When selecting, the slot consisting of DL1 is selected.

  In this way, by selecting one slot from the three slots and transmitting the control information frame CTLF, access points using the same common control channel CCH can transmit the control information frame CTLF in a time division manner.

  As described above, in the embodiment of the present invention, the common control channel CCH is changed according to the hopping pattern in units of time frames, and the control information frame CTLF is transmitted and received in a time division manner, so that collision between 48 cells at the maximum is avoided. Thus, the data channel selection information indicating the data channel used for data frame communication can be exchanged, and the data channel selection information can be shared between the access point 1 and the mobile terminal 11.

  In addition, since the map indicating all the usage states of the channels CH1 to CH80 is included in the control information frame CTLF and transmitted from the access point to the mobile terminal in units of time frames (every 5 ms), both the frequency direction and the time direction It is possible to effectively use free frequency resources that change from time to time.

  The operations of the access points 2 to i and the mobile terminals 12 to 1i included in the cells C2 to Ci are also executed according to the flowchart shown in FIG.

  In the above description, the hopping pattern of the common control channel CCH has been described as consisting of the hopping pattern shown in FIG. 7. However, in the embodiment of the present invention, the hopping pattern of the common control channel CCH is not limited to this. Consists of a hopping pattern described below.

  In the radio communication system 100, synchronization between the cells C1 to Ci is maintained. For this reason, all hopping patterns of the common control channel need to be designed so as not to collide with each other.

  In order to ensure fairness of transmission opportunities for control information, each hopping pattern uses a uniform frequency band in order to average the probability of occurrence of interference between radio systems in the frequency and time directions. In addition, adjacent common control channels need to be used with a certain interval. Furthermore, in order to avoid resource selection contention during distributed dynamic channel selection in a multi-cell environment, it is desirable that a certain number of hopping patterns always use common control channels that are close together on the frequency axis.

  A generalized hopping pattern that satisfies this purpose will be described.

  First, the following conditions are assumed.

  (Condition 1) N (N is an integer of 2 or more) channels are arranged at equal intervals on the frequency axis.

(Condition 2) differs from G (G is an integer of 2 or more) of simultaneously receivable number of channels (corresponding to reception bandwidth) B g kinds of radios (2 ≦ B 1 <B 2 <··· <B G = N) exists.

(Condition 3) The ratio R g + 1 = B g + 1 / B g of the number of receivable channels with the radio device one lower order is an integer multiple of any g = 1, 2,..., G−1. It is.

  The hopping pattern has the following structure.

(Structure 1) Each hopping pattern uses all channels once within one period. (Structure 2) All hopping patterns use different channels at each time. (Structure 3) N channels are B in numerical order. G-1 or by (N / B G-1) is divided into pieces of the primary channel block, each hopping pattern using the primary channel block alternately (structure 4) N kinds hopping pattern, B in numerical order G-1 types are divided into (N / B G-1 ) primary pattern groups, and patterns belonging to the same primary pattern group use channels belonging to the same primary channel block at each time point (Structure 5 ) is B G-g-number of channels constituting each g following channel block, in numerical order B G-g-1 or by (N / B G-g- 1) pieces of (g + 1) Is divided into channel blocks, each hopping pattern, the (g + 1) using the following channel block alternately (Structure 6) B G-g different hopping patterns constituting each g following channel block, B G-g in numerical order -1 types (N / B G-g-1 ) divided into (g + 1) -order pattern groups, and patterns belonging to the same (g + 1) -order pattern group are assigned to the same (g + 1) -order channel block at each time point. For convenience of description, when R 0 = 1, R 1 = B 1 , R G + 1 = 1, G-order hopping patterns f R1, R2,..., RG satisfying the above structures 1 to 6 are used. (N, j) (nth pattern, jth hop) is expressed by the following equation.

In Equation (2), P g [x] represents an arbitrary substitution for the input x = 0, 1,..., R g−1 .

  It is to be noted that the entire created hopping pattern is subjected to replacement between any two channels (column replacement in FIG. 7) and replacement between arbitrary two times (row replacement in FIG. 7), so that the structure 1 and It is possible to create a new hopping pattern that satisfies structure 2.

[Specific Example 1]
Hopping pattern is represented by equation (1) is, R 1 = 4, R 2 = 2, R 3 = 2, and P g [x] = when x hopping pattern f 4,2,2 (n, j).

[Specific Example 2]
Further, the secondary hopping pattern f 5,3 (n, j) when R 1 = 5, R 2 = 3, and P g [x] = x is expressed by the following equation.

  FIG. 11 is a diagram illustrating a hopping pattern represented by Expression (3). A hopping pattern represented by Expression (3) is illustrated in FIG.

  As described above, in the embodiment of the present invention, the access points 1 to i hop the common control channel in units of time frames using the hopping pattern generally expressed by the equation (2), and after the hopping When the common control channel is unused, the control information frame CTLF including a map indicating the usage status of the channels CH1 to CH80 is transmitted to the mobile terminals 11 to 1i. Then, the mobile terminals 11 to 1i determine the data channel used for transmission / reception of the data frame by using the usage status of the channels CH1 to CH80 included in the control information frame CTLF received from the access points 1 to i to determine the access points 1 to 1i. send to i.

  Therefore, even when the frequency band used for wireless communication by the access points 1 to i and the mobile terminals 11 to 1 i changes, data channel selection information (=) for selecting a data channel while avoiding interference with other wireless systems. A map showing the usage status of channels CH1 to CH80).

  In the embodiment of the present invention, each of the access points 1 to i constitutes a “radio device” or a “first radio device”, and each of the mobile terminals 11 to 1 i has a “second radio”. Device ".

  In addition, that the access points 1 to i transmit and receive control information frames in units of time frames corresponds to the access points 1 to i transmitting and receiving control information frames periodically.

  Furthermore, transmission / reception of the control information frame in units of time frames by the mobile terminals 11 to 1i corresponds to that the mobile terminals 11 to 1i periodically transmit / receive the control information frame.

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

  The present invention is applied to a radio apparatus capable of efficiently sharing channel selection information while avoiding interference with other radio systems. Further, the present invention is applied to a radio communication system including a radio apparatus that can efficiently share channel selection information while avoiding interference with other radio systems.

  1 to i access point, 11 to 1i mobile terminal, 100 wireless communication system, 101 and 111 antenna, 102 and 112 transmission means, 103 and 113 reception means, 104 selection means, 105 hopping table, 106 and 115 synchronization establishment means, 114 Channel determination means.

Claims (9)

  1. There are a plurality of cells each managed by one base station, and a wireless device used in a wireless communication environment in which a plurality of different wireless systems are mixed,
    Selection means for periodically selecting a common control channel from a frequency band used by the plurality of wireless systems by a frequency hopping method;
    Based on the received signal strength information in the frequency band, carrier sense is performed on the common control channel selected by the selection means, and the selected common control channel is used when the selected common control channel is unused. Transmitting means for periodically transmitting data channel selection information for selecting a data channel used for data communication using
    A cell that measures received signal strength in the frequency band and generates received signal strength information related to the selected common control channel, outputs the generated received signal strength information to the transmitting means, and manages the radio device A radio apparatus comprising: reception means for periodically receiving from the mobile terminal a data channel used for data communication determined by the mobile terminal existing in the mobile terminal using the data channel selection information.
  2.   The radio apparatus according to claim 1, wherein the transmission unit transmits the data channel selection information in a time frame unit using a time division method.
  3.   The transmission means stops transmission of the data channel selection information in the time frame when the selected common control channel is used, and the selection means selects the frequency hopping method in the next time frame. The radio apparatus according to claim 2, wherein transmission of the data channel selection information is attempted using a common control channel.
  4.   The radio according to claim 1, wherein the selection unit holds a hopping table indicating a hopping pattern of the common control channel in advance, and selects the common control channel for each time frame with reference to the hopping table. apparatus.
  5. The total number of the common control channels is N (N is an integer of 2 or more), and the number of wireless devices having mutually different channels that can be received simultaneously is G (G is an integer of 2 or more). When receivable number of channels and B 1 ~B G,
    The hopping table is
    Each hopping pattern uses all channels once within a period,
    At each time, all hopping patterns use different channels,
    N number of the common control channel is divided into B G-1 or by (N / B G-1) number of primary channel block in numerical order, the hopping pattern using each primary channel block alternately,
    N types of hopping patterns are divided into BG-1 types (N / B G-1 ) primary pattern groups in numerical order, and patterns belonging to the same primary pattern group are the same primary channel block at each time point. Use channels belonging to
    g (g = 1~G-2) B G-g -number of channels constituting the next channel block in numerical order B G-g-1 or by (N / B G-g- 1) pieces of (g + 1) following Divided into channel blocks, and the hopping pattern uses each (g + 1) th order channel block alternately,
    The BG -g types of hopping patterns constituting each g-order pattern group are divided into ( G / G-1 ) number of (g + 1) -th order pattern groups by BG -g-1 types in order of numbers. The radio apparatus according to claim 4 , wherein the pattern belonging to the (g + 1) next pattern group uses a channel belonging to the same (g + 1) next channel block at each time point.
  6. A wireless communication system used in a wireless communication environment in which a plurality of cells each managed by a single base station and a plurality of different wireless systems are mixed,
    A first wireless device;
    A second wireless device that performs wireless communication with the first wireless device;
    The first radio apparatus periodically selects a common control channel from a frequency band used by the plurality of radio systems by a frequency hopping method, performs carrier sense on the selected common control channel, and performs the selection. When the common control channel is not used, first data channel selection information for selecting a data channel to be used for data communication using the selected common control channel is periodically sent to the second radio apparatus. And periodically receiving from the second wireless device a data channel used for data communication determined by the second wireless device using the first data channel selection information,
    The second wireless device periodically receives the first data channel selection information from the first wireless device, and the received first data channel selection information and usable data observed by itself. The data channel used for data communication is periodically determined using the second data channel selection information indicating the channel, and the determined data channel is periodically transmitted to the first wireless device using the common control channel. A wireless communication system for transmitting data.
  7.   The wireless communication system according to claim 6, wherein the first and second wireless devices transmit and receive data frames to each other in a time division manner using the data channel.
  8.   The second radio apparatus receives third data channel selection information for selecting a data channel used for data communication from a third radio apparatus belonging to a cell other than the cell to which the second radio apparatus belongs. The wireless communication system according to claim 6, wherein the data channel is determined using third data channel selection information.
  9.   The radio communication system according to claim 6, wherein the second radio apparatus determines the data channel while avoiding a collision with a channel used in a cell other than the cell to which the second radio apparatus belongs.
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