JP6549023B2 - Wireless communication system, wireless communication method and central control station - Google Patents

Description

  The present invention relates to a wireless communication system, a wireless communication method, and a wireless communication method for improving the reduction in throughput due to control of Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) of each communication station in a dense area of wireless LAN (Local Area Network). It relates to a central control station.

  In recent years, with the spread of portable high-performance wireless terminals such as notebook computers and smartphones, wireless LANs of the IEEE 802.11 standard have been widely used not only in businesses and public spaces but also in general homes. The wireless LANs of the IEEE 802.11 standard include a wireless LAN of the IEEE 802.11b / g / n standard which uses the 2.4 GHz band and a wireless LAN of the IEEE 802.11 a / n / ac standard which uses the 5 GHz band.

  In a wireless LAN of the IEEE 802.11b standard or the IEEE 802.11g standard, 13 channels are prepared at intervals of 5 MHz between 2400 MHz and 2483.5 MHz. However, when using multiple channels at the same place, it is possible to simultaneously use up to three channels or even up to four channels at the same time by using channels so that spectra do not overlap to avoid interference.

  In the case of the wireless LAN of the IEEE 802.11a standard, in Japan, a total of 19 channels of 8 channels and 11 channels not overlapping with each other are defined between 5170 MHz and 5330 MHz and between 5490 MHz and 5710 MHz. In the IEEE 802.11a standard, the bandwidth per channel is fixed at 20 MHz.

  The maximum transmission rate of the wireless LAN is 11 Mbps in the case of the IEEE 802.11b standard, and 54 Mbps in the case of the IEEE 802.11a standard and the IEEE 802.11g standard. However, the transmission rate here is the transmission rate on the physical layer. Actually, since the transmission efficiency at the MAC (Medium Access Control) layer is about 50 to 70%, the upper limit of the actual throughput is about 5 Mbps in the IEEE 802.11b standard, and 30 Mbps in the IEEE 802.11a standard or the IEEE 802.11g standard It is an extent. In addition, the transmission rate is further reduced as the number of communication stations attempting to transmit information increases.

  On the other hand, for wired LANs, the spread of Fiber to the home (FTTH) using optical fiber in each home, including Ethernet (registered trademark) 100Base-T interface, offers 100Mbps to 1Gbps high-speed circuits. It is widely used, and a further increase in transmission speed is required for wireless LANs.

  Therefore, in the IEEE 802.11n standard, which was standardized in 2009, the channel bandwidth, which has been fixed at 20 MHz, is expanded to 40 MHz at the maximum, and in addition, MIMO (Multiple input multiple output) technology Implementation was decided. If transmission and reception are performed by applying all the functions defined in the IEEE802.11n standard, it is possible to realize a communication speed of up to 600 Mbps in the physical layer.

  Furthermore, the IEEE 802.11ac standard, which has been standardized in 2013, extends the channel bandwidth to 80 MHz and up to 160 MHz, and multi-user MIMO (MU) using Space Division Multiple Access (SDMA). The introduction of a transmission method has been decided (for example, see Non-Patent Document 1). When transmission and reception are performed by applying all the functions defined in the IEEE 802.11ac standard, the physical layer can realize a communication speed of up to about 6.9 Gbps.

  However, when the channel bandwidth is increased to 40 MHz, 80 MHz, and 160 MHz in the IEEE 802.11ac standard, the number of channels that can be used simultaneously at the same location in the 5 GHz band is nine channels, although the channel bandwidth is 19 channels at 20 MHz. There are fewer channels and two channels. That is, as the channel bandwidth increases, the number of available channels will decrease.

  Thus, depending on the channel bandwidth used for communication, the number of channels that can be used simultaneously at the same location is three in the 2.4 GHz band wireless LAN, and two, four, nine, or 19 channels in the 5 GHz band wireless LAN. Therefore, when actually introducing a wireless LAN, it is necessary for the wireless base station (access point (AP)) to select a channel to be used in its own cell (BSS: Basic Service Set).

  Here, in a dense LAN environment where the number of BSSs is larger than the number of available channels, multiple BSSs use the same channel (OBSS: Overlapping BSS). In that case, the interference between BSSs using the same channel will reduce the throughput of the BSS and the entire system. Therefore, in the wireless LAN, autonomous distributed access control is used, which uses CSMA / CA to transmit data only when the channel is open due to carrier sense.

  Specifically, the communication station that has generated a transmission request first performs carrier sense for a predetermined sensing period (DIFS: Distributed Inter-Frame Space) to monitor the state of the wireless medium, and during this time, transmission by another communication station is performed. If no signal is present, random backoff is performed. The communication station continues to perform carrier sensing during the random backoff period, but during this time, if there is no transmission signal from another communication station, it acquires the channel Opportunity (TXOP). A communication station (TXOP Holder) that has obtained the right to use a channel can transmit data to other communication stations in the same BSS, and receive data from those communication stations. When performing such CSMA / CA control, in a dense LAN environment using the same channel, the frequency of the channel becoming busy due to carrier sense increases, so the transmission opportunity (the opportunity to obtain the right to use the channel) decreases. And throughput will be reduced. Therefore, it is important to monitor the surrounding environment and select an appropriate channel.

  Although the channel selection method in the wireless base station is not defined in the IEEE 802.11 standard, each vendor adopts a unique method, but the channel with the least interference power is the most common channel selection method. There is a method to select in an autonomous distributed manner. The AP performs carrier sense on all channels for a predetermined period, selects a channel with the smallest interference power, and transmits / receives data to / from a subordinate terminal apparatus on the selected channel. The interference power is a level of a signal received from a neighboring BSS or another system, and can be measured by, for example, a Received Signal Strength Indicator (RSSI).

  Here, when carrier sense is performed in the radio base station, a Clear Channel Assessment (CCA) threshold is set to determine the channel usage status using received signal strength indicator (RSSI). For example, in the IEEE 802.11 standard, two CCA thresholds are defined. One is a CCA threshold (hereinafter referred to as a CCA-SD (Signal Detection) threshold) when the preamble of the wireless LAN signal can be detected in the received signal received in the carrier sense, and the other is a carrier This is a CCA threshold (hereinafter, referred to as a CCA-ED (Energy Detection) threshold) when the preamble of the wireless LAN signal can not be detected in the received signal received in the sense. For example, in the IEEE 802.11a standard, the CCA-SD threshold is set to -82 dBm. The CCA-ED threshold is set to -62 dBm.

  If the RSSI is equal to or higher than the CCA-SD threshold and carrier frequency detection detects a preamble of a wireless LAN signal, it is determined that the channel is busy (communication is not possible). Also, even if the preamble of the wireless LAN signal can not be detected by the carrier sense, if the RSSI is equal to or higher than the CCA-ED threshold, it is regarded as an interference wave from the neighboring BSS or other systems and the channel is determined to be busy (communication not possible). . Otherwise, it is determined that the channel is idle (communicable).

  In addition, the IEEE 802.11 standard defines a procedure for changing channels in the case where radio conditions around the BSS change, but basically, except for forced transition by radar detection, etc., reselection of a channel once selected. Did not go. That is, in the current wireless LAN, channel optimization has not been performed according to changes in the wireless status.

IEEE 802.11ac Standard, December 2013.

  Existing wireless LAN systems operate in an autonomous distributed manner. Also, as described above, each wireless base station selects a channel to be used based on the surrounding wireless environment at the time of activation, and reselection of the channel selected once is not basically performed. The environmental change includes, for example, a change in the number of radio base stations in operation, a change in a radio terminal under control of each radio base station, and a change in the amount of data transmitted from a radio apparatus in each cell. However, in the existing wireless LAN system, even if there is such a change in the environment, the channel used is not optimized, so that there is a difference between the throughputs of each base station or each terminal, and the throughput value is not good. There is a problem that the system becomes fair and the throughput of the entire system is degraded.

  An object of the present invention is to provide a wireless communication system, a wireless communication method, and a central control station capable of improving the throughput of wireless base stations (APs) and wireless terminals and improving the throughput of the entire system in a dense LAN environment. I assume.

According to a first aspect of the present invention, communication control of each wireless base station is performed according to a plurality of wireless base stations performing wireless communication with the respective wireless terminals under control, and environment information and capability information around a plurality of wireless base stations or wireless terminals. A wireless communication system comprising: a central control station for controlling parameters to be used, wherein the plurality of wireless base stations comprise wireless environment information notification means for acquiring surrounding environment information and capability information and notifying the central control station The central control station performs simultaneous transmission to a group of radio base stations selected as a radio base station that performs simultaneous transmission on the same frequency according to the environment information and capability information notified from a plurality of radio base stations. with simultaneous transmission control means for controlling the allocation of channels and bandwidth as a parameter, simultaneous transmission control means of the centralized control station informs the radio base station group for simultaneous transmission on the same frequency An allocatable channel list creating means for creating an allocatable channel list indicating allocatable channels, and an allocatable bandwidth list indicating allocatable bandwidths for a group of radio base stations performing simultaneous transmission on the same frequency; Allocatable bandwidth list creation means to be created, bandwidth allocation means for allocating bandwidth from the allocatable bandwidth list to the wireless base station group performing simultaneous transmission on the same frequency, simultaneous transmission on the same frequency And a channel assignment unit for assigning a channel from the assignable channel list to a group of wireless base stations to be performed.

  The allocatable channel list creation means of the central control station in the wireless communication system according to the first invention detects a radar signal within a predetermined period, a channel that is not a predetermined allocation target channel, from among the channels available in the wireless base station group. Assigned channels can be allocated excluding all or some of the channels in use by radio base stations outside the system that can not be managed by the central control station, and by radio base stations not controlled by the central control station It is a configuration to create a channel list.

  The allocatable bandwidth list creation means of the central control station in the wireless communication system according to the first invention is, for each bandwidth of the allocatable bandwidth list, starting of a cell using the bandwidth in the channel of the allocatable channel list. It is determined based on a predetermined primary channel selection rule whether or not it is possible, and the allocatable channel list is configured to exclude the bandwidth in which the cell can not be started up to create the allocatable bandwidth list. It is.

  In the wireless communication system according to the first aspect of the present invention, the allocatable bandwidth list creation means of the central control station includes, among the bandwidths of the allocatable bandwidth list, a wireless base station group or a wireless base station group and all radios belonging to it. The configuration is such that an allocatable bandwidth list is created by excluding bandwidths larger than each available bandwidth of the terminal.

  The bandwidth allocation means of the central control station in the wireless communication system according to the first invention is configured to allocate the maximum bandwidth or the minimum bandwidth allocatable from the allocatable bandwidth list to the wireless base station group. .

  The channel assignment means of the central control station in the wireless communication system according to the first invention excludes, from the assignable channel list, channels already assigned to wireless base stations belonging to neighboring wireless base stations from the assignable channel list. Furthermore, the minimum number of channels included in the allocatable channel list in neighboring radio base stations are selected and allocated.

  The channel assignment means of the central control station in the wireless communication system according to the first aspect of the invention is configured to perform channel assignment by excluding channels other than a predetermined recommended channel from the assignable channel list.

According to a second aspect of the present invention, communication control of each wireless base station is performed according to a plurality of wireless base stations performing wireless communication with each subordinate wireless terminal, and environment information and capability information around a plurality of wireless base stations or wireless terminals. A wireless communication method comprising: controlling a parameter to be used; and controlling parameters of a wireless base station group selected as a wireless base station performing simultaneous transmission on the same frequency, the plurality of wireless base stations comprising: Acquiring the environment information and capability information and notifying the central control station, the central control station is configured to transmit the radio base station group to the radio base station group according to the environment information and the capability information notified from the plurality of radio base stations , have a simultaneous transmission control step of controlling the allocation of channels and bandwidth as parameters for performing simultaneous transmission, simultaneous transmission control step of the centralized control station, sending simultaneously at the same frequency Step 1 of creating an allocatable channel list indicating allocatable channels for the group of radio base stations that perform the above process, and allocation that indicates allocatable bandwidth for the group of radio base stations that perform simultaneous transmission on the same frequency. Step 2 of creating a possible bandwidth list, step 3 of assigning a bandwidth from the allocatable bandwidth list to a group of wireless base stations performing simultaneous transmission on the same frequency, and wireless transmission of simultaneous transmission on the same frequency And Step 4 of assigning a channel from the assignable channel list to the base station group.

According to a third aspect of the present invention, communication control of each wireless base station is performed according to a plurality of wireless base stations performing wireless communication with each subordinate wireless terminal, and environment information and capability information around a plurality of wireless base stations or wireless terminals. A centralized control station of a wireless communication system, comprising: a centralized control station for controlling parameters to be used, and controlling parameters of a wireless base station group selected as a wireless base station performing simultaneous transmission on the same frequency, comprising a plurality of wireless base stations depending on the environmental information and the capability information is notified from the radio base station group includes a simultaneous transmission control means for controlling the allocation of channels and bandwidth as parameters for performing simultaneous transmission and simultaneous transmission control means Assignable channel list creation for creating an assignable channel list indicating assignable channels for a wireless base station group performing simultaneous transmission on the same frequency And an allocatable bandwidth list creating unit that creates an allocatable bandwidth list indicating allocatable bandwidths to a group of radio base stations that perform simultaneous transmission on the same frequency and a radio that performs simultaneous transmission on the same frequency Allocate a channel from among the allocatable channel list to the bandwidth allocation means for allocating bandwidth from the allocatable bandwidth list to the base station group and to the radio base station group performing simultaneous transmission on the same frequency And channel assignment means.

  The present invention allocates channels and bandwidths to a wireless base station group (cluster) simultaneously transmitting on the same frequency in accordance with wireless environment information in the vicinity of a wireless base station in a dense LAN environment. This enables efficient reuse of frequency channels, and improves the throughput of the radio base station and the radio terminal and the throughput of the entire system.

It is a figure which shows the Example structure of the radio | wireless communications system of this invention. It is a figure which shows the structural example of the central control station 8 in the radio | wireless communications system of this invention. It is a figure which shows the structural example of the wireless base station 1 in the radio | wireless communications system of this invention. It is a figure which shows the structural example of the radio | wireless terminal 4 in the radio | wireless communications system of this invention. It is a flowchart which shows the outline | summary of the process sequence of the central control station in the radio | wireless communications system of this invention. It is a figure which shows the example of preparation of the allocatable channel list | wrist of cluster C (n). It is a flowchart which shows the outline | summary of the channel assignment algorithm with respect to cluster attribution AP. It is a flowchart which shows the example of a preparation procedure of the allocatable channel list | wrist of cluster C (n) of step S12. It is a flowchart which shows preparation procedure example 1 of the allocatable bandwidth list | wrist of cluster C (n) of step S13. It is a flowchart which shows preparation procedure example 2 of the allocatable bandwidth list | wrist of cluster C (n) of step S13. It is a flowchart which shows preparation procedure example 3 of the allocatable bandwidth list | wrist of cluster C (n) of step S13. It is a flowchart which shows the determination procedure example 1 of the allocation channel of belonging AP of cluster C (n) of step S17. It is a flowchart which shows determination procedure example 2 of allocation channel of belonging AP of cluster C (n) of step S17.

FIG. 1 shows the configuration of an embodiment of a wireless communication system of the present invention.
In FIG. 1, wireless base stations (AP) 1 to 3 perform wireless communication with the wireless terminals (STAs) 4 to 6 to which they belong. Here, it is assumed that the wireless terminals 4 and 5 belong to the wireless base station 1, there is no wireless terminal to be assigned to the wireless base station 2, and the wireless terminal 6 belongs to the wireless base station 3. The wireless base stations 1 and 2 are connected to the central control station 8 via the network 7, and the wireless base stations 3 are connected to the network 9 outside the management of the central control station 8.

  The central control station 8 collects environment information (radio environment information, traffic information, current setting information) and capability information from the radio base stations 1 and 2 or the radio terminals 4 and 5, and simultaneously on the same frequency based on the radio environment information. Create a cluster, which is a combination of multiple wireless base stations capable of transmission, and further, based on environment information and capability information, a channel for each cluster as a setting parameter value used for communication control of multiple wireless base stations for each cluster. And determine bandwidth. By this, unlike the conventional CSMA / CA access control, the opportunity for simultaneous transmission of a plurality of wireless base stations on the same frequency per cluster is increased, thereby improving the throughput of wireless base stations and wireless terminals and improving the overall system throughput. can do.

  Here, examples of (1) wireless environment information, (2) traffic information, (3) current setting information, and (4) capability information are shown below.

(1) Wireless environment information Peripheral wireless environment information measured by a wireless base station (AP) and a wireless terminal (STA), for example, the number of neighboring APs, each SSID, each BSSID (MAC address), a frame transmitted by each The received RSSI value, each used channel, each used bandwidth, each capability information, each AP belonging terminal number, time occupancy information, each traffic information, etc. Also, it is radio environment information on the belonging terminal measured by the AP, and radio environment information on the connection destination AP measured by the STA.

(2) Traffic information Traffic volume to the belonging terminal which AP accommodates in the buffer, traffic volume to connection destination AP which STA accommodates in the buffer, traffic rate input to the buffer of AP / STA, AP / STA It is the traffic rate etc. sent out from the buffer.

(3) Current setting information The present operation standard (11a / b / g / n / ac type), channel, bandwidth, etc. of AP and STA.

(4) Capability information Available standards (11a / b / g / n / ac), available frequency bands, available bandwidth, etc.

FIG. 2 shows a configuration example of the central control station 8 in the wireless communication system of the present invention.
In FIG. 2, the central control station 8 sets the connection unit 81, the communication unit 82, the control unit 83, the information collection unit 84, the information storage unit 85, the information processing unit 86, and the parameter calculation unit 87. And an information storage unit 88.

  The communication unit 82 communicates with the wireless base stations 1 and 2 and the wireless terminals 4 and 5 via the connection unit 81. The information collection unit 84 collects environment information (radio environment information, traffic information, current setting information) and capability information from the control target radio base stations 1 and 2 or the radio terminals 4 and 5 present in the radio communication system. The information storage unit 85 holds each piece of information collected by the information collection unit 84. The information processing unit 86 performs averaging, updating, and the like of each piece of information held by the information storage unit 85. The parameter calculation unit 87 uses the information processed by the information processing unit 86 and the information held by the information storage unit 85 to set a parameter value used to create a cluster of the radio base station and control communication of the radio base station. Calculate The setting information storage unit 88 holds the setting parameter value of the radio base station calculated by the parameter calculation unit 87. The control unit 83 centrally controls the operation of the central control station 8 including collection of each information of the radio base stations 1 and 2 and the radio terminals 4 and 5, creation of clusters of radio base stations, and calculation of setting parameter values.

FIG. 3 shows a configuration example of the wireless base station 1 in the wireless communication system of the present invention. The radio base station 2 also has the same configuration.
In FIG. 3, the wireless base station 1 includes a connection unit 11, a communication unit 12, a control unit 13, an environment information holding unit 14, a parameter setting unit 15, an access right acquisition unit 16, and a wireless communication unit 17. , And an antenna unit 18.

  The communication unit 12 communicates with the central control station 8 on the network 7 via the connection unit 11. The environment information holding unit 14 holds the environment information acquired by periodically scanning around the radio base station. Here, the environment information includes the number and identification information of other wireless base stations existing in each available channel, the RSSI of a signal such as a beacon received from another wireless base station, and the like. Furthermore, the number of terminal devices in the own cell and the RSSI and SINR of signals received from each terminal device are also included. The parameter setting unit 15 sets the parameter notified from the central control station 8. The access right acquisition unit 16 acquires the access right by CSMA / CA. The wireless communication unit 17 uses the parameters set by the parameter setting unit 15 to obtain an access right by CSMA / CA, and performs wireless communication with the belonging terminal apparatus via the antenna unit 18. Further, the wireless communication unit 17 scans each of the channels available for wireless communication for a predetermined period, and outputs the obtained environmental information on the periphery to the environmental information holding unit 14. The control unit 13 integrally controls the operation of the radio base station.

FIG. 4 shows a configuration example of the wireless terminal 4 in the wireless communication system of the present invention. The wireless terminal 5 has the same configuration.
In FIG. 4, the wireless terminal 4 includes a control unit 41, an environment information holding unit 42, an access right acquisition unit 43, a wireless communication unit 44, and an antenna unit 45.

  The environment information holding unit 42 holds environment information acquired by periodically scanning around the wireless terminal. Here, the environment information includes the number and identification information of other wireless base stations existing in each available channel, the RSSI of a signal such as a beacon received from another wireless base station, and the like. Furthermore, the RSSI, SINR, etc. of the signal received from the belonging radio base station are also included. The access right acquisition unit 43 acquires an access right by CSMA / CA. The wireless communication unit 44 performs wireless communication with a wireless base station via the antenna unit 48. Further, the wireless communication unit 44 scans each of the channels available for wireless communication for a predetermined period, and outputs the obtained environmental information on the periphery to the environmental information holding unit 42. The control unit 41 centrally controls the operation of the wireless terminal.

(Processing procedure of central control station)
FIG. 5 shows an outline of the processing procedure of the central control station in the wireless communication system of the present invention.
In FIG. 5, the central control station collects environmental information such as surrounding radio environment information, traffic information, and setting information from the connected radio base station and performs necessary processing (S1). Next, based on the collected radio environment information, the central control station creates a cluster which is a combination of a plurality of radio base stations AP capable of simultaneous transmission on the same frequency (S2). Next, channel assignment is performed for each wireless base station AP belonging to the cluster (S3), and the process is finished. In addition, when assigning channels to each radio base station AP belonging to a cluster, change the CCA threshold used for carrier sense in order to increase transmission opportunities or in consideration of interference and interference that occur with neighboring BSSs. Processing such as

  The present invention relates to channel assignment (channel and bandwidth assignment) to each radio base station AP belonging to the cluster in step S3, which will be described in detail below.

(Channel assignment algorithm for cluster attributable AP)
FIG. 7 shows an outline of a channel assignment algorithm for a cluster-attributable AP.
In FIG. 7, one cluster C (n) is selected from the clusters whose channel has not been determined (S11), and a channel list that can be assigned to the belonging AP of cluster C (n) is created (S12). A bandwidth list that can be allocated to the belonging AP of cluster C (n) is created (S13), and the processes of steps S12 and S13 are performed for all clusters for which the channel has not been determined (S14).

  Subsequently, one cluster C (n) is selected from clusters whose channel has not been determined (S15), and based on the allocatable channel list and allocatable bandwidth list of each cluster created in steps S11 to S14, The bandwidth to be allocated to the belonging AP of cluster C (n) is determined (S16), the channel to be allocated to the belonging AP of cluster C (n) is determined (S17), and for all clusters whose channel is not determined, step S16, The process of S17 is performed (S18).

  The details of step S12 will be described with reference to FIGS. 6 and 8, the details of step S 13 with reference to FIGS. 9 to 11, and the details of step S 17 with reference to FIGS. 12 to 13.

(Details of step S12)
FIG. 6 shows an example of creating an allocatable channel list of cluster C (n).
In FIG. 6, there are AP1 to AP5 as in-system APs, and APx, APy, and APz as out-system APs. A line connects APs that can be detected mutually. Here, AP1, AP2 and AP3 are belonging APs of the cluster C (n), AP4 and AP5 are single APs not belonging to the cluster, and there are no out-of-control APs among the in-system APs.

  Here, it is assumed that there are a total of 19 channels of W52, W53, and W56 available channels in the intra-system AP, for example, in a 5 GHz band wireless LAN system. Among them, a total of eight channels (36, 40, 44, 48, 52, 56, 60, 64) of W52 and W53 are assigned as assignment target channels of the cluster C (n) which the system user selects in advance. On the other hand, channels 36, 40, 56, 64 are used during use by the radar or out-of-system AP. Therefore, among the available channels and the assignment target channels of the cluster C (n), the assignable channels of the cluster C (n) are the channels 44, 48, 52, 60.

FIG. 8 shows an example of the creation procedure of the allocatable channel list of cluster C (n) in step S12.
In FIG. 8, one AP (i) is selected from among the belonging APs of cluster C (n) (S1201), and one channel CH (j) is selected from the available channels in AP (i). (S1202). If even one of the following conditions (S1203 to S1206) can not be cleared for this channel CH (j), the channel C (n) is recorded as an allocatable channel of the cluster C (n) (S1207).

  Condition 1 is whether or not the channel CH (j) is a cluster assignment target channel (S1203). If the channel CH (j) is not a cluster assignment target channel, the channel CH (j) is recorded as a non-assignable channel (S1207). In the example of FIG. 6, the usable channels are 19 channels in total of W52, W53, and W56, and the allocation target channels of cluster C (n) are 8 channels in total of W52 and W53 (36, 40, 44, 48, 52, 56, 60, 64), and other channels become non-assignable channels.

  Condition 2 is whether or not the radar signal is detected within a predetermined period in the channel CH (j) (S1204). Here, the channel CH (j) which has detected the radar signal within a predetermined period (for example, 30 minutes) is recorded as a non-assignable channel (S1207). In the example of FIG. 6, the channel 64 corresponds.

  Condition 3 is whether the channel CH (j) is used by an AP outside the system (APx to APz in the example of FIG. 6) (S1205). In a system in which multiple APs transmit simultaneously on the same frequency, an AP outside the system management can not be controlled, so when the use of a channel CH (j) is detected by an AP outside the system, the channel CH (j) is allocated. The channel is recorded as an unacceptable channel (S1207). In the example of FIG. 6, the channels 36, 40, 56 correspond.

  Condition 4 is whether or not the channel CH (j) is being used by an out-of-control AP among the in-system APs (S1206). In the case of setting the non-control target AP among the intra-system APs that perform simultaneous transmission on the same frequency, when the use of the channel CH (j) is detected by the non-control target AP, the channel CH (j) can not be assigned. It records as a channel (S1207). In the example of FIG. 6, there is no corresponding channel.

  The out-of-system AP or in-system AP being used by an out-of-control AP is not limited to being used as a primary channel, but may be used as a secondary channel (secondary 20 MHz, secondary 40 MHz, secondary 80 MHz) Is also a non-assignable channel.

  As described above, conditions 2 to 4 are conditions for setting the channel CH (j) as the non-assignable channel if the channel CH (j) is in use in an uncontrollable or non-control medium, and the channel CH (j) is unused. Or, it becomes an assignable channel only when the control target AP among the intrasystem APs uses the channel CH (j).

  Although at least one condition 1 to condition 4 may be adopted in any combination, an example in which condition 1 to condition 4 are targets is shown in FIG. If the channel CH (j) can not be cleared even by one of the conditions 1 to 4, it is determined that the channel can not be assigned a cluster.

  Therefore, even if channel CH (j) is an available channel of cluster C (n), cluster C is in use if it is being used by any of the radar, an out-of-system AP, and an out-of-system AP that is not controlled. It records as an allocatable channel of (n) (S1207). The above processing is repeated for all channels of available channels in AP (i) (S1208), and further, for all belonging APs of cluster C (n) (S1209). Finally, the non-assignable channel is excluded from the available channels of cluster C (n), and an allocatable channel list of cluster C (n) is created (S1210). In the example of FIG. 6, channels 44, 48, 52, 64 are assignable channels.

(Details of step S13)
FIG. 9 shows a procedure example 1 of creating the allocatable bandwidth list of cluster C (n) in step S13.
In FIG. 9, one bandwidth b is selected from the known allocatable bandwidth list B (for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, 80 + 80 MHz) (S1301). Next, one channel CH (j) is selected from the assignable channel list of cluster C (n) created in the process of step S12 (FIG. 8) (S1302), and the belonging AP of cluster C (n) is selected. One AP (i) is selected from among (S1303).

  Next, in the selected base station AP (i), it is judged whether or not the wireless LAN cell (BSS) of the bandwidth b can be launched on the channel CH (j) (S1304). In the IEEE 802.11 wireless LAN, when launching a BSS using a bandwidth wider than 20 MHz, there is a rule that secondary channels of other neighboring BSSs can not be used as a primary channel. In the process of step S1304, it is determined based on this primary channel selection rule whether it is possible to start up the cell. If the channel CH (j) does not satisfy the primary channel selection rule, the channel CH (j) is recorded as a non-assignable channel (S1305). Then, the processing of steps S1303 to S1305 is repeated for all belonging APs of cluster C (n) (S1306), and the processing of steps S1302 to S1306 is further performed for all channels of the allocatable channel list of cluster C (n). Repeat (S1307).

  Next, the non-assignable channel recorded in step S1305 is excluded from the allocatable channel list of cluster C (n) in the bandwidth b (S1308). As a result, if all of the assignable channels of cluster C (n) in bandwidth b are excluded as non-assignable channels, then bandwidth b can not be assigned in cluster C (n).

  Therefore, it is determined whether there is a channel registered in the allocatable channel list of cluster C (n) in bandwidth b (S1309), and if there is no channel registered in the allocatable channel list, the unallocatable bandwidth The bandwidth b is recorded as (S1310). Then, for all the bandwidths of the allocatable bandwidth list B, the processing of steps S1301 to S1310 is repeated.

  Finally, the unallocatable bandwidth recorded in step S1310 is excluded from the allocatable bandwidth list B of cluster C (n), and the allocatable bandwidth list of cluster C (n) is created (S1312).

FIG. 10 shows a procedure example 2 of creating an allocatable bandwidth list of cluster C (n) in step S13.
In FIG. 10, one bandwidth b is selected from the known allocatable bandwidth list B (for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, 80 + 80 MHz) (S1321). Next, one AP (i) is selected from the belonging APs of the cluster C (n) (S1322).

  Next, it is determined whether the available bandwidth (capability) of the selected AP (i) is equal to or greater than the bandwidth b (S1323). Are recorded (S1324). Then, the process of steps S1322 to S1324 is repeated for all belonging APs of cluster C (n) (S1325), and the process of steps S1321 to S1325 is repeated for all bandwidths of the allocatable bandwidth list B (S1326) ).

  Finally, the unallocatable bandwidths recorded in step S1324 are excluded from the allocatable bandwidth list B of cluster C (n) to create an allocatable bandwidth list of cluster C (n) (S1327).

FIG. 11 shows a procedure example 3 of creating the allocatable bandwidth list of cluster C (n) in step S13.
In FIG. 11, one bandwidth b is selected from the known allocatable bandwidth list B (for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, 80 + 80 MHz) (S1331). Next, one AP (i) is selected from the belonging APs of the cluster C (n) (S1332).

  Next, it is determined whether or not the available bandwidth of all the terminals belonging to the selected AP (i) and AP (i) is equal to or greater than the bandwidth b (S1333). The bandwidth b is recorded as the bandwidth (S1334). Then, the process of steps S1332 to S1334 is repeated for all belonging APs of cluster C (n) (S1335), and the process of steps S1331 to S1335 is repeated for all bandwidths of the allocatable bandwidth list B (S1336). ).

  Finally, the unallocatable bandwidth recorded in step S1334 is excluded from the allocatable bandwidth list B of cluster C (n) to create an allocatable bandwidth list of cluster C (n) (S1337).

(Details of step S16)
In step S16 of FIG. 7, the determination of the bandwidth to be allocated to the belonging AP of cluster C (n) is made in the allocatable bandwidth list of cluster C (n) created by the processing procedure of FIG. Either the minimum bandwidth or the maximum bandwidth may be selected. If the allocatable bandwidth list of cluster C (n) is empty, there is no bandwidth allocated to the belonging AP of cluster C (n), and there is no channel allocated to cluster C (n), and the cluster C (n) is dismantled.

(Details of step S17)
FIG. 12 shows a procedure example 1 of the assignment channel assignment of the belonging AP of the cluster C (n) in step S17.
In FIG. 12, from the assignable channel list of cluster C (n) created in the process of step S12 (FIG. 8), all channels already assigned to the belonging AP of another cluster existing in the periphery are excluded (S1701 ). Here, the channels to be excluded include not only channels used as primary channels in peripheral clusters but also channels used as secondary channels (secondary 20 MHz, secondary 40 MHz, secondary 80 MHz).

  Next, it is determined whether the allocatable channel list of cluster C (n) is empty (S1702). If empty, there is no channel to be allocated to cluster C (n), and cluster C (n) is not ) Is dismantled (S1703). That is, since there is no channel to be assigned to the cluster C (n), it is regarded as an AP that implements CSMA / CA with a normal parameter value instead of leaving it as an AP that realizes simultaneous transmission.

  On the other hand, if there is an assignable channel in the assignable channel list of the cluster C (n), one channel CH (i) is selected from the assignable channel list (S1708). Here, in the selected channel CH (i), the variable “number of contention APs of channel CH (i)” indicating the number of other cluster belonging APs competing is initialized and the value of the variable is set to zero (S1709 ). Then, the channel CH (i) selects one cluster C (m) from neighboring other clusters which are candidates for assignable channels (S1710). Next, the number of assigned APs of the selected cluster C (m) is added to the number of competing APs of the channel CH (i) (S1711). Then, the process of steps S1710 to S1711 is repeated for all the peripheral clusters of cluster C (n) on which channel allocation is to be performed (S1712), and the process of steps S1708 to S1712 is repeated for all channels of the allocatable channel list. (S1713).

  Finally, among the channels in the allocatable channel list, the channel with the smallest number of contention APs is set as the channel to be allocated to the belonging AP of the cluster C (n) (S1714). Here, when there are a plurality of channels in which the number of competing APs is the smallest, one of them may be selected at random or a primary channel most distant from the candidates may be selected.

  FIG. 13 shows a procedure example 2 of the allocation channel assignment of the belonging AP of the cluster C (n) in step S17. The determination procedure example 2 is obtained by inserting the process of updating the allocatable channel list of the cluster C (n) between steps S1702 and S1708 of the determination procedure example shown in FIG.

  In FIG. 13, from the assignable channel list of cluster C (n) created in the process of step S12 (FIG. 8), all channels already assigned to the belonging AP of another cluster existing in the periphery are excluded (S1701 ). Next, it is determined whether the allocatable channel list of cluster C (n) is empty (S1702). If empty, there is no channel to be allocated to cluster C (n), and cluster C (n) is not ) Is dismantled (S1703).

  On the other hand, if there is an allocatable channel in the allocatable channel list of cluster C (n), it is checked whether the allocation bandwidth of cluster C (n) is larger than 20 MHz (S1704). Here, if the allocation bandwidth of the cluster C (n) is larger than 20 MHz (for example, 40 MHz, 80 MHz, 160 MHz, 80 + 80 MHz), it is checked whether there is a recommended channel set in advance (S1705) If there is a recommended channel, the non-recommended channel is excluded from the allocatable channel list of cluster C (n), and the allocatable channel list of cluster C (n) is updated (S1706). If the allocated bandwidth of the cluster C (n) is 20 MHz or less, or if there is no recommended channel, the allocatable channel list of the cluster C (n) is not updated.

  Next, it is judged whether or not the allocatable channel list is empty as a result of updating the allocatable channel list of cluster C (n) (S1707), and if it is empty, the process proceeds to cluster C (n). There is no channel to be assigned, and cluster C (n) is disassembled (S1703).

  On the other hand, if there is an allocatable channel in the updated allocatable channel list of cluster C (n), the processing of the following steps S1708 to S1713 is the same as the determination procedure example 1 shown in FIG. Among the channels in the channel list, the channel with the smallest number of competing APs is assigned to the belonging AP of cluster C (n) (S1714).

1 to 3 radio base station (AP)
4 to 6 wireless terminals 7 network 8 central control station 9 network (not managed)
11 connection unit 12 communication unit 13 control unit 14 environment information holding unit 15 parameter setting unit 16 access right acquisition unit 17 wireless communication unit 18 antenna unit 41 control unit 42 radio environment information holding unit 43 access right acquisition unit 44 wireless communication unit 45 antenna Unit 81 connection unit 82 communication unit 83 control unit 84 information collection unit 85 information storage unit 86 information processing unit 87 parameter calculation unit 88 setting information storage unit

Claims (4)

A plurality of wireless base stations performing wireless communication with respective subordinate wireless terminals;
A central control station for controlling parameters used for communication control of each wireless base station according to environment information and capability information around the plurality of wireless base stations or the wireless terminal,
The plurality of wireless base stations include wireless environment information notification means for acquiring surrounding environment information and capability information and notifying the centralized control station of the environment information and capability information.
The centralized control station performs simultaneous transmission to a wireless base station group selected as a wireless base station that performs simultaneous transmission on the same frequency according to the environment information and capability information notified from the plurality of wireless base stations. Simultaneous transmission control means for controlling allocation of channels and bandwidths as the parameters to be performed;
The simultaneous transmission control means of the centralized control station
Allocatable channel list creation means for creating an allocatable channel list indicating allocatable channels for the group of radio base stations performing simultaneous transmission on the same frequency;
Allocatable bandwidth list creation means for creating an allocatable bandwidth list indicating allocatable bandwidths for the radio base station group performing simultaneous transmission on the same frequency;
Bandwidth allocation means for allocating bandwidth from the allocatable bandwidth list to the wireless base station group performing simultaneous transmission on the same frequency;
The radio base station group for performing simultaneous transmission with the same frequency, viewing including a channel assignment means for assigning a channel from among the assignable channel list,
The channel assignment means excludes a channel already assigned to a wireless base station belonging to a nearby wireless base station group from the assignable channel list for the wireless base station group, and further assigns the wireless base station in the nearby wireless base station A wireless communication system characterized in that it is configured to select and allocate the minimum number of channels included in the available channel list . In the wireless communication system according to claim 1 ,
The wireless communication system, wherein the channel assignment means is configured to assign channels by excluding channels other than a predetermined recommended channel from the assignable channel list. Control parameters used for communication control of each wireless base station according to a plurality of wireless base stations performing wireless communication with the respective subordinate wireless terminals, and environment information and capability information around the plurality of wireless base stations or the wireless terminals Wireless communication method for controlling parameters of a wireless base station group selected as a wireless base station that performs simultaneous transmission on the same frequency, comprising:
The plurality of wireless base stations have a step of acquiring surrounding environment information and capability information and notifying the central control station of the information.
The central control station allocates channels and bandwidths as the parameters for simultaneous transmission to the wireless base station group according to the environment information and capability information notified from the plurality of wireless base stations. Simultaneous transmission control step to control
The simultaneous transmission control step of the central control station is:
Creating an allocatable channel list indicating allocatable channels for the group of radio base stations performing simultaneous transmission on the same frequency;
Creating an allocatable bandwidth list indicating allocatable bandwidths for the group of radio base stations that perform simultaneous transmission on the same frequency;
Assigning a bandwidth from the allocatable bandwidth list to the wireless base station group performing simultaneous transmission on the same frequency;
The radio base station group for performing simultaneous transmission with the same frequency, viewing including the steps 4 to assign a channel from among the assignable channel list
The step 4 excludes a channel already assigned to a wireless base station belonging to a nearby wireless base station group from the assignable channel list for the wireless base station group, and can further assign the wireless base station group in the nearby wireless base station group. A wireless communication method characterized in that it is configured to select and allocate the minimum number of channels included in the channel list . Control parameters used for communication control of each wireless base station according to a plurality of wireless base stations performing wireless communication with the respective subordinate wireless terminals, and environment information and capability information around the plurality of wireless base stations or the wireless terminals A central control station for controlling a parameter of a wireless base station group selected as a wireless base station performing simultaneous transmission on the same frequency,
Simultaneous transmission control for controlling allocation of channels and bandwidths as the parameters for simultaneous transmission to the wireless base station group according to the environment information and capability information notified from the plurality of wireless base stations Equipped with
The simultaneous transmission control means
Allocatable channel list creation means for creating an allocatable channel list indicating allocatable channels for the group of radio base stations performing simultaneous transmission on the same frequency;
Allocatable bandwidth list creation means for creating an allocatable bandwidth list indicating allocatable bandwidths for the radio base station group performing simultaneous transmission on the same frequency;
Bandwidth allocation means for allocating bandwidth from the allocatable bandwidth list to the wireless base station group performing simultaneous transmission on the same frequency;
The radio base station group for performing simultaneous transmission with the same frequency, viewing including a channel assignment means for assigning a channel from among the assignable channel list
The channel assignment means excludes a channel already assigned to a wireless base station belonging to a nearby wireless base station group from the assignable channel list for the wireless base station group, and further assigns the wireless base station in the nearby wireless base station A centralized control station characterized in that it is configured to select and allocate the minimum number of channels included in the available channel list .

Images