JP5789462B2 - Control device and radio communication system including the same - Google Patents

Description

  The present invention relates to a control device and a wireless communication system including the control device.

  Conventionally, in a wireless communication system including a base station and a terminal device that accesses the base station, the coverage of the base station is maintained while taking into account power saving in the base station (Non-patent Document 1).

  That is, the method disclosed in Non-Patent Document 1 causes an extra base station to sleep while maintaining the coverage (area) when all base stations in the wireless communication system are activated.

  On the other hand, when a base station to be connected is in a sleep state when starting wireless communication, there are wireless systems that wake up the base station (Non-Patent Documents 2 and 3).

Amit P. Jardosh, Konstantina Papagiannaki, Elizabeth M. Belding, Kevin C. Almeroth, Gianluca Iannaccone, Bapi Vinnakota, “Green WLANs: On-Demand WLAN Infrastructures,” Mobile Netw Appl. DOI 10.1007 / s11036-008-0123-8. Tetsuya Ito, Yoshihisa Kondo, Shiro Sakata, Zenji Ikenaga, Hiroyuki Shikata, “Overview of Radio-On-Demand Networks to reduce wasted power consumption”, IEICE General Institute 2011 (B-6-132). Yoshihisa Kondo, Hiroyuki Yomo, Hana Yumoto, Toshiyasu Tanaka, Yuji Iwai, Hideo Tsutsui, Sadao Obana "On-demand wake-up method using wireless LAN signal" IEICE Tech. NS2010-185 (2011-03).

  When a terminal apparatus in Non-Patent Documents 2 and 3 enters a wireless communication system and starts wireless communication, if the base station to be connected is in a sleep state, the terminal apparatus wakes up the base station. Then, the base station that is not woken up by the terminal device maintains the sleep state. Therefore, not all base stations in the wireless communication system are activated, and it is assumed that only some base stations are activated.

  However, the method disclosed in Non-Patent Document 1 sleeps an extra base station while maintaining the coverage (area) when all base stations in the wireless communication system are activated. When only some of the base stations are activated, there is a problem that it is difficult to determine the base station to be operated and the base station to sleep. Since the terminal device wakes up the base station when starting wireless communication, this problem is necessary to ensure the connection to the activated base station of all the terminal devices present in the wireless communication system. The problem is that it is difficult to determine the minimum base station.

  Therefore, the present invention has been made to solve such a problem, and the object thereof is necessary to secure connections to the activated base stations of all terminal devices present in the wireless communication system. To provide a control device capable of determining the minimum number of base stations.

  Another object of the present invention is to provide a control device capable of determining the minimum necessary base station for securing connections to the activated base stations of all the terminal devices existing in the wireless communication system. It is to provide a wireless communication system.

  According to the embodiment of the present invention, the control device includes a reception unit, a storage unit, a creation unit, a determination unit, and a control unit. The receiving unit is configured to wake up by K (K is an integer of 2 or more) terminal devices among M (M is an integer of 2 or more) base stations existing in the wireless communication system. An integer satisfying 1 ≦ m ≦ M) receives an activation signal indicating that m base stations have been activated or a connection request signal indicating that a connection request has been received. The storage means includes a connectable list indicating base stations to which K terminal devices can be connected, K received signal strengths in the K terminal devices, and K number of minimum transmission rates required by each terminal device. Memorize the required minimum speed. According to the activation signal or the connection request signal, the creation means can make all of the K terminal devices have their required minimum speed based on the connectable list, the K received signal strengths, and the K required minimum speed. Link information indicating a connection relationship between m base stations and K terminal devices for wireless communication with any of the m base stations at a transmission rate as close as possible is created. The determining means is based on the link information created by the creating means and uses a base station having only a single wireless communication link with the first terminal apparatus which is any one terminal apparatus as an active base station. The first condition, the second condition for deleting the link with the base station other than the operating base station of the terminal device that can be connected to the base station as the operating base station, the wireless communication link between the terminal device and the second condition The third condition is set such that the third base station having no base station as the sleep base station and the fourth condition using the base station having the most radio communication links with the terminal device as the active base station are sequentially executed. The fourth condition is repeatedly executed to determine an active base station and a sleep base station from m base stations. The control means controls the m base stations so that the base station determined as the active base station by the determining means operates and the base station determined as the sleep base station by the determining means sleeps.

  Further, according to the embodiment of the present invention, the control device includes a receiving unit, a storage unit, a creating unit, a determining unit, and a control unit. The receiving unit is configured to wake up by K (K is an integer of 2 or more) terminal devices among M (M is an integer of 2 or more) base stations existing in the wireless communication system. An integer satisfying 1 ≦ m ≦ M) receives an activation signal indicating that m base stations have been activated or a connection request signal indicating that a connection request has been received. The storage means includes a connectable list indicating base stations to which K terminal devices can be connected, K received signal strengths in the K terminal devices, and K pieces which are the minimum transmission speeds required by each terminal device. Memorize the requested minimum speed. According to the activation signal or the connection request signal, the creation means can make all of the K terminal devices have their required minimum speed based on the connectable list, the K received signal strengths, and the K required minimum speed. Link information indicating a connection relationship between m base stations and K terminal devices for wireless communication with any of the m base stations at a transmission rate as close as possible is created. The determining means is based on the link information created by the creating means and uses a base station having only a single wireless communication link with the first terminal apparatus which is any one terminal apparatus as an active base station. The first condition, the second condition for deleting the link with the base station other than the operating base station of the terminal device that can be connected to the base station as the operating base station, the wireless communication link between the terminal device and the second condition The third condition in which a base station without a sleep base station is set as a sleep base station, and a base station having the least wireless communication link with a terminal device is set as a sleep base station, and wireless that can be connected to the base station as the sleep base station The fourth condition for deleting the communication link from the link information is sequentially executed, and the second to fourth conditions are repeatedly executed to determine the active base station and the sleep base station from the m base stations. The control means controls the m base stations so that the base station determined as the active base station by the determining means operates and the base station determined as the sleep base station by the determining means sleeps.

  Further, according to the embodiment of the present invention, the wireless communication system includes M (M is an integer of 2 or more) base stations, K (K is an integer of 2 or more) terminal devices, a control device, Is provided. Each of the K terminal apparatuses accesses one of the M base stations. The control apparatus determines the active base station and the sleep base station from m base stations (m is an integer satisfying 1 ≦ m ≦ M) waked up by K terminal devices among the M base stations. The base station determined as the operating base station is operated, and the m base stations are controlled so that the base station determined as the sleep base station sleeps. And a control device consists of a control device given in any 1 paragraph of Claims 1-8.

  By applying the first condition, the control device according to the embodiment of the present invention allows a terminal device existing near the end of the area where m base stations are arranged to be a base station (m base stations). A wireless communication link is secured with one of them. In addition, the control device establishes wireless communication links between as many terminal devices as possible and operating base stations by applying the second to fourth conditions, and sleeps unnecessary base stations. When the control device repeatedly executes the second to fourth conditions, the connection of all the terminal devices to the base station is ensured, and the number of base stations to be operated is minimized.

  Therefore, it is possible to determine the minimum necessary base station for securing connections to all active base stations of the K terminal devices existing in the wireless communication system.

  In the wireless communication system according to the embodiment of the present invention, the control device applies the first to fourth conditions described above to determine the active base station and the sleep base station from the m base stations, and operates. The base station determined as the base station operates, and the m base stations are controlled such that the base station determined as the sleep base station sleeps.

  Therefore, it is possible to determine the minimum necessary base station for securing connections to all active base stations of the K terminal devices existing in the wireless communication system.

1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. It is a block diagram which shows the structure of the base station shown in FIG. It is a block diagram which shows the structure of the terminal device shown in FIG. It is a block diagram which shows the structure of the control apparatus shown in FIG. It is a conceptual diagram of the memory content in the memory | storage means shown in FIG. It is a figure which shows the specific example of a connectable list | wrist. It is a conceptual diagram for demonstrating the determination method of an active base station and a sleep base station. It is a conceptual diagram of the other memory content in the memory | storage means shown in FIG. It is a figure which shows the other specific example of a connectable list | wrist. It is a 1st conceptual diagram for demonstrating the other determination method of a working base station and a sleep base station. It is a 2nd conceptual diagram for demonstrating the other determination method of a working base station and a sleep base station. It is a conceptual diagram for demonstrating other determination method of an operation | use base station and a sleep base station. It is a conceptual diagram for demonstrating other determination method of an operation | use base station and a sleep base station. It is a flowchart for demonstrating operation | movement in a radio | wireless communications system. It is a flowchart for demonstrating the detailed operation | movement of step S11 shown in FIG. It is a flowchart for demonstrating the other detailed operation | movement of step S11 shown in FIG. 15 is a flowchart for explaining still another detailed operation of step S11 shown in FIG. 14. It is a flowchart for demonstrating operation | movement when a terminal device detaches | leaves from a radio | wireless communications system.

  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. In addition, although the base station and the terminal device will be described using AP and STA defined by IEEE 802.11 as examples, the applicable range of the present invention is not limited to the form.

  FIG. 1 is a schematic diagram of a radio communication system according to an embodiment of the present invention. Referring to FIG. 1, radio communication system 100 according to an embodiment of the present invention includes base stations 1 to M (M is an integer of 2 or more), terminal apparatuses 11 to 1K (K is an integer of 2 or more), and And a control device 20.

  Base stations 1 to M are connected to the control device 20 via a wired cable 30. Among base stations 1 to M, m (m is an integer satisfying 1 ≦ m ≦ M) wakes up by a wake-up signal from a terminal device (= at least one of terminal devices 11 to 1K). Or a connection request by a probe request frame is received from a terminal device (= at least one of the terminal devices 11 to 1K) when in an activated state. Then, each of the m base stations, when woken up, generates an activation signal DRV1 indicating that it has been activated and transmits it to the control device 20. Further, each of the m base stations, upon receiving a connection request, generates a connection request signal CDM indicating that a connection request has been made during activation, and transmits it to the control device 20.

  In addition, each of the base stations 1 to m generates a beacon frame including a BSSID (Basic Service Set IDentifier), which is an identifier for identifying itself from other base stations after activation, and periodically generates the generated beacon frame. To broadcast. BSSID is the same as the MAC address of the base station.

Further, each of the base stations 1 to _{m includes a} minimum required rate Rate _MINi that is a minimum transmission rate required by the terminal device, a received signal strength RSSI _{i, j} when the terminal device receives a beacon frame _, and each terminal. A packet including a connectable list CNLi indicating a base station to which the apparatus can be connected and the power consumption P _{STAi, j} in each terminal apparatus is received from at least one of the terminal apparatuses 11 to 1K. Here, i represents each of the terminal devices 11 to 1K, and i = 11 to 1K. J represents each of the base stations 1 to m, and j = 1 to m.

Then, each of the base stations 1 to _{m sends} a packet to the requested minimum rate Rate _MINi , received signal strength RSSI _{i, j} , connectable list CNLi, power consumption P _{STAi, j} from the received packet. The MAC address of the transmitted terminal device is extracted, and the extracted minimum required rate Rate _MINi , received signal strength RSSI _{i, j} , connectable list CNLi, and power consumption P _{STAi, j} are associated with the MAC address [MAC address: Requested minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] is created. Then, each of the base stations 1 to _m receives [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B in the downlink _{downj, i} is transmitted to the control device 20 via the wired cable 30.

Further, each of the base stations 1 to _m receives the connection request by the probe request frame, and then receives the requested minimum rate Rate _MINi , the received signal strength RSSI _{i, j} , the connectable list CNLi, and the power consumption P _{STAi, j.} Is received from the terminal device (at least one of the terminal devices 11 to 1K), [MAC address: minimum required rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and the data communication amount B _{downj, i} in the downlink are transmitted to the control device 20 via the wired cable 30.

  Furthermore, when each of the base stations 1 to m does not receive a packet for a certain period from the terminal device (at least one of the terminal devices 11 to 1K) connected to itself, the terminal device It is determined that it has left or is not in use. Then, each of the base stations 1 to m generates a detachment stop notification SEP indicating that the terminal device has left or is not in use, and transmits it to the control device 20.

Further, each of the base stations 1 to _m includes an operation base station that is a base station to be operated, a sleep base station that is a base station to be sleep, and power consumption P _APj of each base station 1 to _m. / Sleep list is received from the control device 20, and the received operation / sleep list is transmitted to the terminal device connected to itself. If each of the base stations 1 to m detects that it is an active base station based on the operation / sleep list, the base station 1-m maintains the operation, and based on the operation / sleep list, If it is detected, it sleeps.

  The terminal devices 11 to 1K are arranged in the wireless communication space. When each of the terminal devices 11 to 1K enters the wireless communication system 100, the terminal devices 11 to 1K generate a wakeup signal WKE and transmit the generated wakeup signal WKE.

Thereafter, each of the terminal devices 11 to 1K performs a background scan, receives a beacon frame from at least one of the base stations 1 to _m, and detects a received signal strength RSSI _{i, j} when the beacon frame is received. To do. Then, each of the terminal devices 11 to 1K creates a connectable list CNLi indicating base stations to which the terminal devices 11 to 1K can connect based on the received beacon frame.

  In addition, the terminal apparatuses 11 to 1K receive beacon frames from at least one of the base stations 1 to m by passive scanning instead of transmitting the wakeup signal WKE and background scanning to the active base station. Then, the connectable list CNLi indicating the base stations to which it can connect may be created.

Further, each of the terminal devices 11 to 1K detects its own power consumption P _{STAi, j} by a method described later.

Then, each of the terminal devices 11 to 1K includes a packet including the required minimum rate Rate _MINi , the received signal strength RSSI _{i, j} , the connectable list CNLi, and the power consumption P _{STAi, j} = [required minimum rate Rate _MINi. / Received signal strength RSSI _{i, j} / Connectable list CNLi / Power consumption P _{STAi, j} ] is generated. Then, each of the terminal devices 11 to 1K sets the generated packet = [required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] to the received signal strength RSSI _{i, It} transmits to the base station (any one of base stations 1 to _m) where _j is the maximum.

Furthermore, each of the terminal devices 11 to 1K transmits a connection request using a probe request frame to the base stations 1 to m when the base stations 1 to m are in an activated state. Thereafter, each of the terminal devices 11 to 1K generates a packet = [required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ], and the generated packet = [ Requested minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] The received signal strength RSSI _{i, j} is the maximum base station (any of base stations 1 to _m ) Send to.

Furthermore, when each of the terminal devices 11 to 1K receives the operation / sleep list from the control device 20, among the operation base stations included in the operation / sleep list, the operation base station having the maximum received signal strength RSSI _{i, j Alternatively} , the connection is changed to an operating base station with the minimum power consumption P _APj .

When receiving the m activation signals DRV1 from the base stations 1 to m, the control device 20 instructs the already connected terminal device to perform a background scan. Thereafter, the control device 20 transmits [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication in the downlink of the base stations 1 to _m . The quantity B _{downj, i} is received from the base stations 1 to _m . Then, the control device 20 will be described later based on [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i.} Thus, the power consumption P _APj and the transmission rate Rate _{j, i} in each of the base stations 1 to _m are obtained.

Then, the control device 20 sets [MAC address: requested minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ], power consumption P _APj and transmission rate Rate _{j, i} . Based on the method described later, whether to operate or sleep is determined for each of the base stations 1 to m. Thereafter, the control device 20 transmits the operation / sleep list to each of the base stations 1 to m and the terminal devices 11 to 1K.

Further, when receiving the withdrawal stop notification SEP from the base station (any one of the base stations 1 to m), the control device 20 instructs the already connected terminal device to perform background scanning. Then, after instructing the background scan, the control device 20 sets [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] to the base stations 1 to _m . If any one of the base stations 1 to m is received, it is determined for each of the base stations 1 to m whether to operate or sleep. Thereafter, the control device 20 transmits the operation / sleep list to each of the base stations 1 to m and the terminal devices 11 to 1K.

Furthermore, when receiving the connection request signal CDM from the base station (any one of the base stations 1 to m), the control device 20 instructs the already connected terminal device to perform background scanning. Then, after instructing the background scan, the control device 20 sets [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] to the base stations 1 to _m . If any one of the base stations 1 to m is received, it is determined for each of the base stations 1 to m whether to operate or sleep. Thereafter, the control device 20 transmits the operation / sleep list to each of the base stations 1 to m and the terminal devices 11 to 1K.

  FIG. 2 is a block diagram showing a configuration of base station 1 shown in FIG. Referring to FIG. 2, base station 1 includes an antenna 110, a switcher 120, a wakeup device 130, a main device 140, and a power source 150.

  The antenna 110 is connected to the wakeup device 130 or the main device 140 via the switcher 120.

  The switch 120 is connected between the antenna 110 and the wakeup device 130 and the main device 140.

  The antenna 110 receives a packet from a terminal device (any one of the terminal devices 11 to 1K) by wireless communication, and outputs the received packet to the wakeup device 130 or the main device 140 via the switch 120. Further, the antenna 110 transmits the packet received from the main device 140 to the terminal device (any one of the terminal devices 11 to 1K) by wireless communication.

  The switcher 120 connects the antenna 110 to the wakeup device 130 or the main device 140 in accordance with the control signal CTL1 from the main device 140.

  The wake-up device 130 receives, for example, 100 μW of power from the power source 150 and is driven by the received power. The wakeup device 130 is connected to the antenna 110 via the switch 120 when the main device 140 is in the sleep state. The wakeup device 130 holds a wakeup ID_com common in the wireless communication system 100 in advance.

  When wakeup device 130 receives wakeup signal WKE from the terminal device (any one of terminal devices 11 to 1K) via antenna 110, wakeup ID included in the received wakeup signal WKE is woken up. It is determined whether or not it matches ID_com. When the wakeup device 130 determines that the wakeup ID matches the wakeup ID_com, the wakeup device 130 generates the activation signal DRV2, and outputs the generated activation signal DRV2 to the main device 140.

  On the other hand, the wakeup device 130 discards the wakeup signal WKE when the wakeup ID does not match the wakeup ID_com. Then, wakeup device 130 waits for reception of wakeup signal WKE.

  Note that the wakeup device 130 has only a function of receiving a packet such as a wakeup signal WKE, and does not have a function of transmitting a packet.

  The main device 140 receives, for example, 7 W of power from the power source 150 and is driven by the received power.

  Further, when the main device 140 is in the sleep state and is activated by the activation signal DRV2 from the wakeup device 130, the main device 140 generates the activation signal DRV1 and controls the generated activation signal DRV1 via the wired cable 30. Transmit to device 20.

  Further, the main device 140 performs wireless communication with the terminal device connected to the base station 1 via the antenna 110 when in the activated state.

  Further, when the main apparatus 140 is in the activated state, when receiving a connection request using a probe request frame from the terminal apparatus (at least one of the terminal apparatuses 11 to 1K), the main apparatus 140 generates a connection request signal CDM, and the generated connection request The signal CDM is transmitted to the control device 20 via the wired cable 30.

  Furthermore, the main device 140 receives the operation / sleep list from the control device 20 via the wired cable 30 and connects the received operation / sleep list to the base station 1 (= terminal devices 11 to 1K). At least one). The main apparatus 140 maintains operation if the base station 1 is an active base station included in the operation / sleep list, and is activated if the base station 1 is a sleep base station included in the operation / sleep list. To go to sleep.

Further, the main device 140 sends the packet = [minimum required rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] via the antenna 110 to the terminal devices (terminal devices 11 to 1K). From the received packet, the request minimum rate Rate _MINi , the received signal strength RSSI _{i, j} , the connectable list CNLi, the power consumption P _{STAi, j,} and the transmission source of the packet The MAC address of the terminal device is taken out. Thereafter, the main device 140 associates the retrieved minimum required rate Rate _MINi , received signal strength RSSI _{i, j} , connectable list CNLi, and power consumption P _{STAi, j} with the MAC address [MAC address: minimum required rate Rate. _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] is created. Then, the main apparatus 140 determines [MAC address: minimum required rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i in the downlink.} Is transmitted to the control device 20 via the wired cable 30.

  The power supply 150 supplies 100 μW of power to the wakeup device 130 and supplies 7 W of power to the main device 140.

  The switch 120 includes a switch 121 and terminals 122 and 123. Wake-up device 130 includes a wake-up signal receiver 131 and a wake-up determiner 132. The main device 140 includes a wireless communication module 141, a wired communication module 142, and a host system 143.

  The switch 121 is connected to the antenna 110. The terminal 122 is connected to the wakeup signal receiver 131. The terminal 123 is connected to the wireless communication module 141.

  The switch 121 receives a control signal CTL1 from the host system 143 of the main device 140. The switch 121 connects the antenna 110 to the terminal 122 or the terminal 123 by the control signal CTL1.

  In this case, the control signal CTL1 is an L (logic low) level signal or an H (logic high) level signal. The switch 121 connects the antenna 110 to the terminal 122 when the control signal CTL1 is an L level signal, and connects the antenna 110 to the terminal 123 when the control signal CTL1 is an H level signal.

  The wakeup signal receiver 131 has only a function of receiving a packet and does not have a function of transmitting a packet.

  The wakeup signal receiver 131 has a channel X set to one frequency of a wireless communication band (= 2.45 GHz band). The wakeup signal receiver 131 waits for a wakeup signal on the channel X when the switch 121 is connected to the terminal 122.

  When the wakeup signal receiver 131 receives the wakeup signal WKE via the antenna 110, the wakeup signal receiver 131 demodulates the received wakeup signal WKE and outputs the demodulated wakeup signal WKE to the wakeup determiner 132.

  The wakeup determination unit 132 holds a wakeup ID_com in advance. The wakeup determination unit 132 receives the wakeup signal WKE from the wakeup signal receiver 131. Then, wakeup determination unit 132 extracts a wakeup ID included in the received wakeup signal WKE.

  Then, the wakeup determination unit 132 determines whether or not the wakeup ID matches the wakeup ID_com. When it is determined that the wakeup ID matches the wakeup ID_com, the wakeup determination unit 132 generates the activation signal DRV2 and outputs the generated activation signal DRV2 to the host system 143 of the main device 140. On the other hand, when it is determined that the wakeup ID does not match the wakeup ID_com, the wakeup determination unit 132 discards the extracted wakeup ID.

  In the wireless communication module 141, a channel Z (= frequency channel having one frequency of 2.45 GHz band) used for data communication with a terminal device connected to the base station 1 is set in advance.

  When receiving the command signal COM1 from the host system 143, the wireless communication module 141 shifts from the activated state to the sleep state, and when receiving the command signal COM2 from the host system 143, the wireless communication module 141 shifts from the sleep state to the activated state.

  The wireless communication module 141 periodically broadcasts a beacon frame via the antenna 110. Thereafter, the wireless communication module 141 establishes a wireless communication link with the terminal device. The wireless communication module 141 performs wireless communication with a terminal device that has established a wireless communication link. In this case, when receiving a packet from a terminal device that has established a wireless communication link, the wireless communication module 141 extracts data from the received packet and outputs the data to the host system 143. Further, the wireless communication module 141 generates a packet including data received from the host system 143 and transmits the packet to the terminal device.

Further, the wireless communication module 141 outputs the data communication amount B _{downj, i} in the _downlink to the host system 143.

  Further, when the wireless communication module 141 receives a connection request based on the probe request frame from the terminal device (at least one of the terminal devices 11 to 1K) via the antenna 110 during activation, the wireless communication module 141 receives the received connection request from the host system 143. Output to.

  The wired communication module 142 receives control information such as an operation / sleep list from the control device 20 via the wired cable 30, and outputs the received control information to the host system 143.

  Further, the wired communication module 142 receives control information such as the activation signal DRV1 and the connection request signal CDM from the host system 143, and transmits the received control information to the control device 20 via the wired cable 30.

  Further, when the wired communication module 142 receives the command signal COM1 from the host system 143, the wired communication module 142 shifts from the activated state to the sleep state, and upon receiving the command signal COM2 from the host system 143, the wired communication module 142 shifts from the sleep state to the activated state.

  Upon receiving the activation signal DRV2 from the wakeup determiner 132, the host system 143 shifts from the sleep state to the activation state, generates a command signal COM2, and outputs the command signal COM2 to the wireless communication module 141 and the wired communication module 142. In addition, the host system 143 generates an H-level control signal CTL1 and outputs it to the switcher 120. Then, the host system 143 generates the activation signal DRV1 and transmits the generated activation signal DRV1 to the control device 20 via the wired communication module 142 and the wired cable 30.

  When the host system 143 receives a connection request based on the probe request frame from the wireless communication module 141, the host system 143 generates a connection request signal CDM, and controls the generated connection request signal CDM via the wired communication module 142 and the wired cable 30. Transmit to device 20.

Further, the host system 143 includes the minimum required rate Rate _MINi , the received signal strength RSSI _{i, j} , the connectable list CNLi, the power consumption P _{STAi, j} , the MAC address of the terminal device, and the data communication amount B _{downj, When i} is received from the wireless communication module 141, the received minimum required rate Rate _MINi , received signal strength RSSI _{i, j} , connectable list CNLi, and power consumption P _{STAi, j} are associated with the MAC address [MAC address: Requested minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] is created. Then, the host system 143 performs wire communication between [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and the data communication amount B _{downj, i.} The data is transmitted to the control device 20 via the module 142 and the wired cable 30.

  Further, the host system 143 receives the operation / sleep list from the control device 20 and outputs the received operation / sleep list to the wireless communication module 141. Then, if the base station 1 is an active base station included in the operation / sleep list, the host system 143 outputs a command signal COM2 to the wireless communication module 141 and the wired communication module 142. Further, if the base station 1 is a sleep base station included in the operation / sleep list, the host system 143 outputs a command signal COM1 to the wireless communication module 141 and the wired communication module 142, and outputs an L level control signal CTL1. Output to the switch 120.

  Each of base stations 2 to M shown in FIG. 1 has the same configuration as base station 1 shown in FIG.

  FIG. 3 is a block diagram showing a configuration of the terminal device 11 shown in FIG. With reference to FIG. 3, the terminal device 11 includes an antenna 21, a wireless communication module 22, a wakeup signal transmitter 23, and a host system 24.

The wireless communication module 22 performs background scanning via the antenna 21. Thereafter, when receiving the beacon frame, the wireless communication module 22 detects the received signal strength RSSI _{i, j} when the beacon frame is received. Then, the wireless communication module 22 outputs the detected received signal strength RSSI _{i, j} and the beacon frame to the host system 24.

Further, the wireless communication module 22 receives an operation / sleep list from the base station (= any one of the base stations 1 to m) via the antenna 21. The wireless communication module 22 then connects to the active base station having the maximum received signal strength RSSI _{i, j} or the active base station having the minimum power consumption P _APj among the active base stations included in the active / sleep list. change.

  Further, when the wireless communication module 22 receives a connection request based on the probe request frame from the host system 24, the wireless communication module 22 transmits the received connection request via the antenna 21.

Further, when the wireless communication module 22 receives the power consumption P _{STAi, j} in the terminal device 11, the connectable list CNLi and the required minimum rate Rate _MINi in the terminal device 11 from the host system 24, the wireless communication module 22 receives the required minimum rate Rate _MINi and the received signal. Packet including strength RSSI _{i, j} , connectable list CNLi, and power consumption P _{STAi, j} = [required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] And the generated packet = [requested minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] via the antenna 21 is received signal strength RSSI _{i, j} Is the largest base station (any of base stations 1 to m) Send to.

  Furthermore, when a wireless communication link is established with the base station 1, the wireless communication module 22 performs wireless communication with the base station 1 via the antenna 21.

  In this case, the wireless communication module 22 receives a packet from the base station 1 via the antenna 21, demodulates the received packet, extracts data, and outputs the extracted data to the host system 24. The wireless communication module 22 receives data from the host system 24, generates a packet including the received data, modulates the generated packet by a modulation method using a wireless LAN, and transmits the modulated packet via the antenna 21. To the base station 1.

  The wakeup signal transmitter 23 holds a wakeup ID_com in advance. When receiving the command signal COM3 from the host system 24, the wakeup signal transmitter 23 generates a wakeup signal WKE including the wakeup ID_com.

  Then, the wake-up signal transmitter 23 modulates the wake-up signal WKE by an on-off keying modulation scheme, and transmits the modulated wake-up signal WKE to the base station 1 through the antenna 21 via the channel X.

  This on / off keying modulation scheme is a modulation scheme with a transmission rate of several tens of kbps to several hundreds of kbps, and the transmission rate is lower than the modulation scheme used in a normal wireless LAN. The reason why the wake-up signal WKE is modulated by the modulation method having a low transmission rate in this way is to enable the wake-up signal WKE to be demodulated by the wake-up device 130 operating at a very low power of 100 μW.

  When the terminal apparatus 11 enters the wireless communication system 100, the host system 24 outputs a command signal COM3 to the wakeup signal transmitter 23.

Further, the host system 24 receives the beacon frame and the received signal strength RSSI _{i, j} received by the wireless communication module 22 via the antenna 21 from the wireless communication module 22. Then, the host system 24 extracts and manages the ESSID or BSSID included in the received beacon frame, and based on the ESSID or BSSID, the host system 24 obtains a connectable list CNLi that is a list of base stations to which the terminal device 11 can be connected. create.

Furthermore, the host system 24 holds in advance the required minimum speed Rate _MINi of the terminal device 11. Further, the host system 143 detects the power consumption P _{STAi, j} in the terminal device 11 by a method described later. Then, the host system 24 _outputs the required minimum speed Rate _MINi , the connectable list CNLi, and the power consumption P _{STAi, j} to the wireless communication module 22.

  Further, the host system 24 generates a connection request using a probe request frame, and outputs the generated connection request to the wireless communication module 22.

  Further, the host system 24 receives data from the wireless communication module 22, generates data, and outputs the data to the wireless communication module 22.

  Each of the terminal devices 12 to 1K illustrated in FIG. 1 has the same configuration as the terminal device 11 illustrated in FIG.

  FIG. 4 is a block diagram showing a configuration of the control device 20 shown in FIG. Referring to FIG. 4, control device 20 includes receiving means 41, control means 42, storage means 43, creation means 44, determination means 45, and transmission means 46.

  The receiving means 41 receives m activation signals DRV1 from the base stations 1 to m, and outputs the received m activation signals DRV1 to the control means 42.

  The receiving unit 41 receives the connection request signal CDM from the base station (at least one of the base stations 1 to m), and outputs the received connection request signal CDM to the control unit 42.

Further, the receiving means 41 receives [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i.} 1 to _m , and the received [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i} is output to the control means 42.

  Further, the receiving means 41 receives the leave stop notification SEP from the base station (at least one of the base stations 1 to m), and outputs the received leave stop notification SEP to the control means 42.

  The control means 42 receives m activation signals DRV1 from the reception means 41, generates an instruction signal DIR1 for instructing to perform a background scan according to the received m activation signals DRV1, The generated instruction signal DIR1 is transmitted to the terminal devices connected to the base stations 1 to m through the transmission means 46.

Further, the control means 42 receives [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i.} 41, and the received [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i} Store in the storage means 43 for each i.

  Further, the control means 42 generates an instruction signal DIR2 for instructing to determine an active base station and a sleep base station, and outputs the instruction signal DIR2 to the creation means 44.

  Further, the control means 42 receives the withdrawal stop notification SEP from the reception means 41, generates an instruction signal DIR1 in response to the received withdrawal stop notification SEP, and sends the generated instruction signal DIR1 via the transmission means 46. It transmits to the terminal device already connected to the base stations 1 to m.

  Further, the control means 42 receives the connection request signal CDM from the reception means 41, generates an instruction signal DIR1 in accordance with the received connection request signal CDM, and transmits the generated instruction signal DIR1 to the base via the transmission means 46. It transmits to the terminal device already connected to the stations 1 to m.

  Further, when receiving the operation / sleep list from the determination unit 45, the control unit 42 transmits the received operation / sleep list to each of the base stations 1 to m and the terminal devices 11 to 1K via the transmission unit 46.

The storage means 43 stores [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i} for each terminal device i. To do.

Upon receipt of the instruction signal DIR2 from the control means 42, the creation means 44 stores [MAC address: required minimum speed Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ]. Read from. The creation unit 44, the readout: based [MAC address request minimum speed _{Rate MINi} / received signal strength RSSI _{i, j} / connectable list CNLi / power _{P STAi, j]} the received signal strength RSSI _{i of} the _j Thus, the transmission rate Rate _{j, i} in each of the base stations 1 to _m is obtained by the method described later. After that, the creating unit 44, based on [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and transmission rate Rate _{j, i} , By the method described later, all of the terminal devices 11 to _1K and the base station 1 to m and the terminal device 11 for performing wireless communication with any of the base stations 1 to _m at a transmission rate as close as possible to the required minimum rate Rate _MINi. Link information indicating a connection relationship with ˜1K is created. Then, the creation unit 44 outputs the created link information and the transmission rate Rate _{j, i} to the determination unit 45.

The determination unit 45 receives the link information and the transmission rate Rate _{j, i} from the generation unit 44. Then, the determination unit 45 stores [MAC address: required minimum rate Rate _MINi / received signal strength RSSI _{i, j} / connectable list CNLi / power consumption P _{STAi, j} ] and data communication amount B _{downj, i} from the storage unit 43. read out. Thereafter, the determining unit 45 calculates the power consumption P _{APj in} each of the base stations 1 to _m by a method described later based on the data communication amount B _{downj, i} and the transmission rate Rate _{j, i} .

Then, the determination unit 45 determines whether to operate or sleep for each of the base stations 1 to _m by a method described later based on the link information, the power consumption P _{STAi, j} and the power consumption P _APj. The operation / sleep list is created and output to the control means 42.

  The transmission means 46 receives the instruction signal DIR1 from the control means 42, and transmits the received instruction signal DIR1 to the terminal devices connected to the base stations 1 to m.

  Furthermore, the transmission means 46 transmits the operation / sleep list to each of the base stations 1 to m and the terminal devices 11 to 1K.

A method of detecting the power consumption P _APj and the transmission rate Rate _{j, i} of each base station 1 to _m will be described. In the control device 20, the creating means 44 is a relationship between the received signal strength RSSI _{i, j} , the transmission rate Rate _{j, i of the} wireless communication module 141 _, and the power consumption P _Txj (Rate _{j, i} ) per unit data amount. Is stored in advance.

  Table TBL1 is shown in Table 1.

Here, the received signal strength RSSI _{i, j} is the received signal strength in the terminal device i. Accordingly, Table 1 correlates the received signal strength RSSI _{i, j at the} terminal device i with the transmission rate Rate _{j, i} and the power consumption P _Txj (Rate _{j, i} ) per unit data amount at the base station j. Is.

The creation unit 44 reads the received signal strength RSSI _{i, j} and the data communication amount B _{downj, i} from the storage unit 43.

Then, the creating unit 44 detects the transmission rate Rate _{j, i} corresponding to the read received signal strength RSSI _{i, j} with reference to the table TBL1.

Then, the creation unit 44 outputs the detected transmission rate Rate _{j, i} to the determination unit 45.

As described above, the creating unit 44 detects the transmission rate Rate _{j, i} at the base station j that performs radio communication with the terminal device i using the received signal strength RSSI _{i, j} at the terminal device i. This is because in the radio communication link between the terminal device i and the base station j, the received signal strength RSSI _{j, i at the} base station j is changed to the received signal strength RSSI _{i, j} at the terminal device i due to the symmetry of radio communication. It is based on being equal.

The determination unit 45 receives the transmission rate Rate _{j, i} from the creation unit 44. Further, the determination unit 45 holds in advance the power consumption P _Idlej and Table 1 when the base stations 1 to _m are not communicating. Further, the determination unit 45 reads the data communication amount B _{downj, i} from the storage unit 43.

Then, the determination unit 45 refers to Table 1 and detects the power consumption P _Txj (Rate _{j, i} ) corresponding to the transmission rate Rate _{j, i} .

Then, the determination unit 45 calculates the power consumption P _APj in each of the base stations ₁ to _m by substituting the power consumption P _Idlej , the data communication amount B _{downj, i} and the power consumption P _Txj (Rate _{j, i} ) into the following equation. To do.

A method for detecting the power consumption P _{STAi, j} in each of the terminal devices 11 to 1K will be described. In each terminal device 11～1K, wireless communication module 22 detects data traffic _{B upi} in the uplink, and outputs the detected data traffic _{B upi} to the host system 24.

The host system 24 holds in advance a table TBL2 indicating the relationship between the power consumption P _Idlei and the setting value of DTIM (Delivery Traffic Indication Message) when the terminal devices 11 to 1K are not communicating. In addition, the host system 24 holds in advance a table TBL3 indicating the relationship _among the received signal strength RSSI _{i, j} , the transmission rate Rate _{i, j,} and the power consumption P _Txi (Rate _{i, j} ) per unit data amount. ing.

  Tables TBL2 and TBL3 are shown in Tables 2 and 3, respectively.

The host system 24 receives the received signal strength RSSI _{i, j} and the data communication amount B _upi from the wireless communication module 22 and receives the DTIM setting values set by the users of the terminal apparatuses 11 to 1K from the outside. Then, the host system 24 detects the power consumption P _Idlei corresponding to the received DTIM setting value with reference to the table TBL2. When the host system 24 has not received the set value of DTIM, the host system 24 refers to _TBL2 and detects a power consumption P _idle of 5 [W] corresponding to “no set value”.

Further, the host system 24 detects the transmission rate Rate _{i, j} and the power consumption P _Txi (Rate _{i, j} ) corresponding to the received signal strength RSSI _{i, j} with reference to the table TBL3.

Then, the host system 24 calculates the power consumption P _{STAi, j} in each of the terminal devices 11 to 1K by substituting the power consumption P _Idlei , the data communication amount B _upi and the power consumption P _Txi (Rate _{i, j} ) into the following equation. .

  FIG. 5 is a conceptual diagram of the contents stored in the storage means 43 shown in FIG. FIG. 6 is a diagram showing a specific example of the connectable list CNLi. Further, FIG. 7 is a conceptual diagram for explaining a method of determining an active base station and a sleep base station.

  The wireless communication system 100 includes base stations 1 to 3 and terminal devices 11 to 14. In this case, the base stations 1 to 3 are assumed to be woken up by a wakeup signal WKE from at least one of the terminal devices 11 to 14.

The wireless communication module 22 of the terminal device 11 receives the beacon frame Beacon1 from the base station 1, and detects the received signal strength RSSI ₁₁ , 1 when the beacon frame Beacon1 is received. Then, the wireless communication module 22 of the terminal device 11 outputs the detected received signal strength RSSI _{11, 1} and the beacon frame Beacon 1 to the host system 24.

Then, the host system 24 of the terminal device 11 receives the beacon frame Beacon1 and the received signal strength RSSI _11,1 . Thereafter, the host system 24 of the terminal device 11 creates the connectable list CNL11 of the terminal device 11 based on the beacon frame Beacon1. In addition, the host system 24 of the terminal device 11 _{obtains the} power consumption _PSTA11 , 1 when the terminal device 11 communicates with the base station 1 by the above-described method.

Then, the host system 24 of the terminal device 11 wirelessly transmits the MAC address MACadd11 of the terminal device 11, the minimum required rate Rate _MIN11 of the terminal device 11, the received signal strength RSSI _11,1 , the connectable list CNL11, and the power consumption P _STA11,1 . The wireless communication module 22 outputs the packet PKT1 including the MAC address MACadd11, the required minimum rate Rate _MIN11 of the terminal device 11, the received signal strength RSSI _11,1 , the connectable list CNL11, and the power consumption P _STA11,1. = [MACadd11 / Rate _MIN11 / RSSI _11,1, / CNL11 / _PSTA11,1 ] is generated. Then, the wireless communication module 22 of the terminal device 11 transmits the generated packet PKT1 to the base station 1 via the antenna 21.

The wireless communication module 141 of the base station 1 receives the packet PKT1 = [MACadd11 / Rate _MIN11 / RSSI _11,1, / CNL11 / _PSTA11,1 ] via the antenna 110, and receives the MAC address MACadd11 from the received packet PKT1. The requested minimum rate Rate _MIN11 , the received signal strength RSSI _11,1 , the connectable list CNL11 and the power consumption P _STA11,1 are read, and the read MAC address MACadd11, the requested minimum rate Rate _MIN11 , the received signal strength RSSI _11,1 , connection The possible list CNL 11 and the power consumption P _{STA 11, 1} are output to the host system 143.

The wireless communication module 141 of the base station 1, the terminal device 11 and the wireless data traffic _{B Down1,11} when communicating, a host system and a data traffic _{B Down1,12} when wireless communication with the terminal device 12 To 143.

Then, the host system 143 of the base station 1 has the MAC address MACadd11, the required minimum rate Rate _MIN11 , the received signal strength RSSI _11,1 , the connectable list CNL11, the power consumption P _STA11,1 and the data communication amount _Bdown1,11 , B. _{Down 1} and ₁₂ are _received from the wireless communication module 141. Then, the host system 143 of the base station 1 associates the required minimum rate Rate _MIN11 , the received signal strength RSSI _11,1 , the connectable list CNL11 and the power consumption P _STA11,1 with the MAC address MACadd11 [MACadd11: Rate _MIN11 / RSSI _11,1 / CNL11 / _PSTA11,1 ] is created, and [MACadd11: Rate _MIN11 / _RSSI11,1 / CNL11 / _PSTA11,1 ] and the data communication amount _Bdown1,11 , _Bdown1,12 are wired. The data is transmitted to the control device 20 via the module 142 and the wired cable 30.

In addition, the wireless communication module 22 of the terminal device 12 receives the beacon frames Beacon1 to Beacon3 from the base stations 1 to 3, respectively, and the received signal strength RSSI _12,1 , RSSI _12, when receiving the beacon frames Beacon1 to _{Beacon3 , 2} , RSSI ₁₂ and ₃ are detected. Then, the wireless communication module 22 of the terminal device 12 outputs the beacon frames Beacon 1 to Beacon 3 and the received signal strengths RSSI ₁₂ , ₁ , RSSI ₁₂ , ₂ , RSSI ₁₂ , ₃ to the host system 24.

Then, the host system 24 of the terminal device 12 receives the beacon frames Beacon 1 to Beacon 3 and the received signal strengths RSSI ₁₂ , ₁ , RSSI ₁₂ , ₂ , RSSI ₁₂ , ₃ . Thereafter, the host system 24 of the terminal device 12 creates a connectable list CNL12 of the terminal device 12 based on the beacon frames Beacon1 to Beacon3. The host system 24 of the terminal apparatus 12, the power consumption _{P STA12,1} when the terminal device 12 to wirelessly communicate with the base station 1-3 respectively, _{P STA12,2,} determined by the method described above the _{P STA12,3.}

Then, the host system 24 of the terminal apparatus 12, MAC address MACadd12 of the terminal device 12, requesting the minimum speed _{Rate MIN12} of the terminal apparatus 12, the received signal strength _{RSSI 12,1, RSSI 12,2, RSSI 12,3} , connectable list The CNL 12 and the power consumption P _STA12 , ₁ , P _STA12 , ₂ , P _STA12 , ₃ are output to the wireless communication module 22, and the wireless communication module 22 includes the MAC address MACadd 12, the required minimum rate Rate _{MIN 12} , the received signal strength RSSI _{12, 1 , RSSI} 12,2, _{RSSI 12,3,} connectable list CNL12 and power dissipation _{P STA12,1, P STA12,2,} packet including _{P STA12,3 PKT2 = [MACadd12 / Rate} MIN12 / RSSI _{12,1 / RSSI 12,2 / RSSI 12,3 /} CNL12 / P STA12,1 / P STA12,2 / P STA12,3] to generate. Then, the wireless communication module 22 of the terminal device 12 transmits the generated packet PKT2 to the base station 2 via the antenna 21. In this case, the terminal apparatus 12 transmits a packet PKT2 to the base station 2, the received signal strength _{RSSI 12,1,} RSSI _12,2, of _{RSSI 12, 3,} receives the beacon frame Beacon2 from the base station 2 This is because the received signal strength RSSI _{12, 2} sometimes obtained is the maximum. Thus, by transmitting the packet PKT2 to the base station 2 from which the maximum received signal strength RSSI _12, 2 is obtained, the required minimum rate Rate _MIN12 , the received signal strength RSSI _12,1 , RSSI _12,2 , RSSI _{12 , 3} , the connectable list CNL 12 and the power consumption P _STA12 , ₁ , P _STA12 , ₂ , P _STA12 , ₃ can be reliably transmitted to the control device 20.

Base station 2 wireless communication module 141, a packet _{PKT2 = [MACadd12 / Rate MIN12 /} RSSI 12,1 / RSSI 12,2 / RSSI 12,3 / CNL12 / P STA12,1 / P STA12,2 via the antenna 110 / _{P STA12,3]} receive, the received packet PKT 2 MAC address MACadd12 from requesting minimum speed _{rate MIN12,} received signal strength _{RSSI 12,1, RSSI 12,2, RSSI 12,3} , connectable list CNL12 and consumption power _{P STA12,1, P STA12,2,} reads the _{P STA12,3,} the readout MAC address MACadd12, required minimum speed _{rate MIN12,} received signal strength _{RSSI 12,1, RSSI 12,2,} RSS _12,3, connectable list CNL12 and power dissipation _{P STA12,1, P STA12,2,} and outputs the _{P STA12,3} to the host system 143.

The wireless communication module 141 of the base station 2, the data traffic _{B Down2,12} when wireless communication with the terminal device 12, the terminal device 13 and the host system and a data traffic _{B Down2,13} when wireless communication To 143.

Then, the host system 143 of the base station 2, MAC address MACadd12, required minimum speed _{Rate MIN12,} received signal strength _{RSSI 12,1, RSSI 12,2, RSSI 12,3} , connectable list CNL12, the power consumption _{P STA12,1} , P _STA12 , 2, P _STA12 , ₃ and data communication amount B _down2 , ₁₂ , B _down2 , ₁₃ are _received from the wireless communication module 141. Then, the host system 143 of the base station 2 has the minimum required rate Rate _MIN12 , received signal strength RSSI ₁₂ , ₁ , RSSI ₁₂ , ₂ , RSSI ₁₂ , ₃ , connectable list CNL ₁₂ , power consumption P _STA12 , ₁ , P _STA12, the _{2, P STA12,3} in association with the MAC address _{MACadd12 [MACadd12: Rate MIN12 / RSSI} 12,1 / RSSI 12,2 / RSSI 12,3 / CNL12 / P STA12,1 / P STA12,2 / P STA12, _3] to create _{a, [MACadd12: Rate MIN12 / RSSI} 12,1 / RSSI 12,2 / RSSI 12,3 / CNL12 / P STA12,1 / P STA12,2 / P STA12,3] and data traffic _{B down2 , 12} , B _{down 2} and ₁₃ are transmitted to the control device 20 via the wired communication module 142 and the wired cable 30.

Further, the wireless communication module 22 of the terminal device 13 receives the beacon frames Beacon2 and Beacon3 from the base stations 2 and 3, respectively, and the received signal strengths RSSI _13,2 and RSSI _13, when receiving the beacon frames Beacon2 and Beacon3, respectively _{. 3} is detected. Then, the wireless communication module 22 of the terminal device 13 outputs the beacon frames Beacon 2 and Beacon ₃ and the received signal strengths RSSI ₁₃ , ₂ , RSSI ₁₃ , ₃ to the host system 24.

Then, the host system 24 of the terminal device 13, the beacon frame Beacon2, Beacon3 and received signal strength _RSSI 13, _2, receives the _{RSSI 13,3.} Thereafter, the host system 24 of the terminal device 13 creates a connectable list CNL13 of the terminal device 13 based on the beacon frames Beacon2 and Beacon3. Further, the host system 24 of the terminal device 13 _obtains the power consumption P _STA13 , ₂ , P _STA13 , 3 when the terminal device 13 performs wireless communication with the base stations 2 and 3 by the method described above.

Then, the host system 24 of the terminal device 13, MAC address MACadd13 of the terminal device 13, requesting the minimum speed _{Rate MIN13} of the terminal apparatus 13, the received signal strength _RSSI 13, _{2, RSSI 13,3,} connectable list CNL13 and power P _STA13,2, outputs _{P STA13,3} to the wireless communication module 22, a wireless communication module 22, MAC address MACadd13, required minimum speed _{rate MIN13,} received signal strength _RSSI 13, _{2, RSSI 13,3,} connectable list CNL13 and power dissipation _{P STA13,2,} packet including _{P STA13,3 PKT3 = [MACadd13 / Rate} MIN13 / RSSI 13,2 / RSSI 13,3 / CNL13 / P STA13,2 / P STA13, To generate]. Then, the wireless communication module 22 of the terminal device 13 transmits the generated packet PKT3 to the base station 2 via the antenna 21. In this case, the receiving of the terminal apparatus 13 transmits a packet PKT3 to the base station 2, the received signal strength _RSSI 13, _2, among the _{RSSI 13,3,} obtained when receiving the beacon frame Beacon2 from the base station 2 This is because the signal strength RSSI _13,2 is the maximum. Thus, by sending a packet PKT3 to the base station 2 to the maximum received signal strength _{RSSI 13, 2} is obtained, requested minimum rate _{Rate MIN13,} received signal strength _RSSI 13, _{2, RSSI 13,3,} connectable list The CNL 13 and the power consumption P _{STA 13} , ₂ , P _{STA 13} , ₃ can be reliably transmitted to the control device 20.

Wireless communication module 141 of the base station 2 receives the packet _{PKT3 = [MACadd13 / Rate MIN13 /} RSSI 13,2 / RSSI 13,3 / CNL13 / P STA13,2 / P STA13,3] via the antenna 110, MAC address MACadd13 from the received packet PKT 3, requested minimum rate _{rate MIN13,} received signal strength _{RSSI 13,2, RSSI 13,3,} connectable list CNL13 and power dissipation _{P STA13,2,} reads the _{P STA13,3,} the read MAC address MACadd13, required minimum speed _{rate MIN13,} received signal strength _{RSSI 13,2, RSSI 13,3,} connectable list CNL13 and power dissipation _{P STA13,2,} the _{P STA13,3} Hosutoshi Output to the stem 143.

Then, the host system 143 of the base station 2, MAC address MACadd13, required minimum speed _{Rate MIN13,} received signal strength _RSSI 13, _{2, RSSI 13,3,} connectable list CNL13 and power dissipation _{P STA13,2, P STA13,3} Is received from the wireless communication module 141. Then, the host system 143 of the base station 2 sends the required minimum rate Rate _MIN13 , the received signal strength RSSI ₁₃ , ₂ , RSSI ₁₃ , ₃ , the connectable list CNL ₁₃ and the power consumption P _{STA 13} , ₂ , P _{STA 13} , ₃ to the MAC address MACadd13. in association _{[MACadd13: Rate MIN13 / RSSI 13,2} / RSSI 13,3 / CNL13 / P STA13,2 / P STA13,3] create and was their creation _{[MACadd13: Rate MIN13 / RSSI 13,2} / and transmits to the _{RSSI 13,3 / CNL13 / P STA13,2 /} P STA13,3] controller via the wired communication module 142 and wire cable 30 to 20.

Further, the wireless communication module 22 of the terminal device 14 receives the beacon frame Beacon 3 from the base station 3 and detects the received signal strength RSSI ₁₄ and 3 when the beacon frame Beacon 3 is received. Then, the wireless communication module 22 of the terminal device 14 outputs the detected received signal strength RSSI ₁₄ and 3 and the beacon frame Beacon 3 to the host system 24.

Then, the host system 24 of the terminal device 14 receives the beacon frame Beacon 3 and the received signal strength RSSI ₁₄ , 3. Thereafter, the host system 24 of the terminal device 14 creates a connectable list CNL14 of the terminal device 14 based on the beacon frame Beacon3. Further, the host system 24 of the terminal device 14 _{obtains the} power consumption _PSTAs 14 and 3 when the terminal device 14 communicates with the base station 3 by the above-described method.

Then, the host system 24 of the terminal device 14, MAC address MACadd14 of the terminal device 14, requesting the minimum speed _{Rate MIN14} of the terminal apparatus 14, the received signal strength _{RSSI 14, 3,} connectable list CNL14 and power dissipation _{P STA14,3} radio and output to the communication module 22, a wireless communication module 22, MAC address MACadd14, required minimum speed _{rate MIN14,} received signal strength _{RSSI 14, 3,} packets including connectable list CNL14 and power dissipation _{P STA14,3} PKT4 = [MACadd14 / generating a _{Rate MIN14 / RSSI 14,3 / CNL14 /} P STA14,3]. Then, the host system 24 of the terminal device 14 transmits the generated packet PKT4 to the base station 3 via the wireless communication module 22 and the antenna 21.

Wireless communication module 141 of the base station 3, the packet _PKT4 = via the antenna _{110 [MACadd14 / Rate MIN14 / RSSI} 14,3 / CNL14 / P STA14,3] receives, MAC address MACadd14 from the packet PKT4 that the received, The requested minimum rate Rate _MIN14 , the received signal strength RSSI ₁₄ , 3, the connectable list CNL ₁₄ and the power consumption P _{STA 14} , ₃ are read, and the read MAC address MACadd 14, the requested minimum rate Rate _MIN14 , the received signal strength RSSI ₁₄ , 3, connection The possible list CNL 14 and the power consumption P _{STA 14, 3} are output to the host system 143.

The wireless communication module 141 of the base station 3 includes a data traffic _{B Down3,12} when wireless communication with the terminal device 12, the data traffic _{B Down3,13} when wireless communication with the terminal device 13, the terminal device The data communication amount B _down3 , 14 when wirelessly communicating with the data 14 is output to the host system 143.

Then, the host system 143 of the base station 3, MAC address MACadd14, required minimum speed _{Rate MIN14,} received signal strength _{RSSI 14, 3,} connectable list CNL14, power consumption _{P STA14,3} and data traffic _{B down3,12, B Down3,13} and _Bdown3,14 are _received from the wireless communication module 141. Then, the host system 143 of the base station 3 is requested minimum rate _{Rate MIN14,} received signal strength _{RSSI 14, 3,} connectable list CNL14 and power dissipation _{P STA14,3} in association with the MAC address MACadd14 _{[MACadd14: Rate MIN14} / create an _{RSSI 14,3 / CNL14 / P STA14,3]} , [MACadd14: Rate MIN14 / RSSI 14,3 / CNL14 / P STA14,3] and data traffic _{B down3,12, B down3,13, B down3 , 14} are transmitted to the control device 20 via the wired communication module 142 and the wired cable 30.

The receiving means 41 of the control device 20 receives [MACadd11: _RateMIN11 / _RSSI11,1 / CNL11 / _PSTA11,1 ] and the data communication amount _Bdown1,11 , _Bdown1,12 from the base station 1, and receives them. [MACadd11: _RateMIN11 / _RSSI11,1 / CNL11 / _PSTA11,1 ] and the data communication amount _Bdown1,11 , _Bdown1,12 are output to the control means 42.

The receiving means 41 of the control device _{20, [MACadd12: Rate MIN12 / RSSI} 12,1 / RSSI 12,2 / RSSI 12,3 / CNL12 / P STA12,1 / P STA12,2 / P STA12,3] and data traffic _{B Down2,12,} receives _{B Down2,13} from the base station 2, and the received _{[MACadd12: Rate MIN12 / RSSI 12,1} / RSSI 12,2 / RSSI 12,3 / CNL12 / P STA12,1 / P _STA12,2 / P _STA12,3 ] and the data communication amount B _down2,12 , B _down2,13 are output to the control means 42.

Furthermore, the receiving means 41 of the control device _{20, [MACadd13: Rate MIN13 / RSSI} 13,2 / RSSI 13,3 / CNL13 / P STA13,2 / P STA13,3] was received from the base station 2, and the received _{[MACadd13: Rate MIN13 / RSSI 13,2} / RSSI 13,3 / CNL13 / P STA13,2 / P STA13,3] outputs to the control means 42.

Furthermore, the receiving means 41 of the control device _{20, [MACadd14: Rate MIN14 / RSSI} 14,3 / CNL14 / P STA14,3] and data traffic _{B down3,12, B down3,13,} the base station _{B Down3,14} received from the 3 and the received _{[MACadd14: Rate MIN14 / RSSI 14,3} / CNL14 / P STA14,3] and data traffic _{B down3,12, B down3,13,} outputs _{B Down3,14} to the control means 42 To do.

Then, the control means 42 of the control device 20 receives [MACadd11: Rate _MIN11 / RSSI _11,1 / CNL11 / _PSTA11,1 ] and data communication amount _Bdown1,11 , _Bdown1,12 etc. from the reception means 41, The received [MACadd11: _RateMIN11 / _RSSI11,1 / CNL11 / _PSTA11,1 ] and data communication amount _Bdown1,11 , _Bdown1,12, etc. are stored in the storage means 43 as information IFO1 shown in FIG.

  The creation means 44 of the control device 20 reads the information IFO1 shown in FIG. 5 from the storage means 43 in response to the instruction signal DIR2 from the control means 42. Then, the creation unit 44 detects that the terminal device 11 is connectable to the base station 1 based on the connectable list CNL11 (see FIG. 6A) of the information IFO1.

  Further, the creation unit 44 detects that the terminal device 12 is connectable to the base stations 1 to 3 based on the connectable list CNL12 (see FIG. 6B) of the information IFO1.

  Hereinafter, similarly, the creation unit 44 detects that the terminal device 13 is connectable to the base stations 2 and 3 based on the connectable list CNL13 (see FIG. 6C) of the information IFO1, Based on the connectable list CNL14 of the information IFO1 (see FIG. 6D), it is detected that the terminal device 14 is connectable to the base station 3.

  Then, the creation unit 44 establishes wireless communication links ML1 to ML7 (= shown by dotted lines) that can be connected between the base stations 1 to 3 and the terminal devices 11 to 14 based on the detection result ( (See (b) of FIG. 7).

Since the base station 1 includes the wireless communication links ML1 and ML2 that can be connected to the terminal devices 11 and 12, respectively, the creation unit 44 of the control device 20 allows the base station 1 to perform wireless communication with the terminal device 11. a transmission rate _{rate 1, 11,} and obtains a transmission rate _{rate 1, 12} when the base station 1 carries out radio communication with terminal apparatuses 12, determination unit 45 obtains the power consumption _{P AP1} at the base station 1.

More specifically, creation means 44, based on the first line of the received signal strength _{RSSI 11,1} information IFO1, the table TBL1 transmission rate _{Rate 1, 11} corresponding to the received signal strength _{RSSI 11,1} Detect by reference. Further, creation means 44, based on the second line of the received signal strength _{RSSI 12,1} information IFO1, referring to detect the transmission rate _{Rate 1, 12} a table TBL1 corresponding to the received signal strength _{RSSI 12,1} To do.

The transmission rate Rate ₁ , ₁₁ is a transmission rate in the base station 1 when the base station 1 performs wireless communication with the terminal device 11, and the transmission rate Rate ₁ , ₁₂ is transmitted from the base station 1 to the terminal device 12. It is the transmission speed in the base station 1 when performing.

Then, the creating unit 44 outputs the detected transmission rates Rate _1,11 , Rate _1,12 to the determining unit 45.

The determination unit 45 receives the transmission rates Rate _1,11 and Rate _1,12 . Then, determination unit 45 refers to the table TBL1, corresponding to the transmission rate _{Rate 1, 11} to detect the power consumption _P TX1 _{(Rate 1,11),} the power consumption corresponding to the transmission rate _{Rate 1, 12 P TX1} (Rate _1,12 ) is detected.

The power consumption P _TX1 (Rate _1,11 ) is the power consumption per unit data in the base station 1 when the base station 1 performs wireless communication with the terminal device 11, and the power consumption P _TX1 (Rate _1,12 ) is The power consumption per unit data in the base station 1 when the base station 1 performs wireless communication with the terminal device 12.

The determination means 45, the information from the first line of data traffic _{B Down1,11} and second line of data traffic _{B Down1,12} of IFO1, power consumption _{P idle1,} the power consumption _{P TX1} that the detected Substituting (Rate _1,11 ) and P _TX1 (Rate _1,12 ) into Equation (1), power consumption P _AP1 in the base station 1 is obtained.

Further, since the base station 2 has the wireless communication links ML3 and ML4 with the terminal devices 12 and 13, respectively, the creation means 44 and the determination means 45 are similarly configured so that the base station 2 performs wireless communication with the terminal device 12. the transmission rate _{rate 2, 12} when performing a transmission rate _{rate 2, 13} at which the base station 2 performs the terminal device 13 and wireless communication, and a power consumption _{P AP2} at the base station 2 obtains.

Further, since the base station 3 has the wireless communication links ML5 to ML7 with the terminal devices 12 to 14, respectively, the creating unit 44 and the determining unit 45 are similarly configured so that the base station 3 performs wireless communication with the terminal device 12. Transmission rate Rate _3,12 when the base station 3 performs wireless communication with the terminal device 13 and transmission rate Rate _3,13 when the base station 3 performs wireless communication with the terminal device 13. Rates ₃ and ₁₄ and power consumption P _AP3 in the base station 3 are obtained.

Then, the creation unit 44 uses the following two conditions as a base station to which each terminal apparatus 11 to 14 can connect a base station capable of wireless communication at a transmission speed as close as possible to its required minimum speed Rate _MINi. The wireless communication link is established between the base stations 1 to 3 and the terminal apparatuses 11 to 14.

  (Cnd1) A base station satisfying the required minimum speed of the terminal device is set as a connectable base station, and a link is established.

  (Cnd2) When there is no base station that satisfies the required minimum speed, a base station that can obtain the highest transmission speed is set as a connectable base station, and a link is established.

More specifically, creation unit 44, the required minimum speed _{Rate MIN11} the first row of the information IFO1, based on the transmission rate _{Rate 1, 11,} transmission rate _{Rate 1, 11} is required minimum base station 1 If the rate is more than Rate _MIN11 , a wireless communication link MLC1 (shown by a solid line) is established between the base station 1 and the terminal device 11 as a base station to which the base station 1 can be connected ((c) in FIG. 7) reference). In addition, when the transmission rate Rate _1,11 is smaller than the required minimum rate Rate _MIN11 , the creating unit 44 can connect the terminal device 11 only to the base station 1, so that the transmission rate Rate _1,11 of the base station 1 is set. A wireless communication link MLC1 (shown by a solid line) is established between the base station 1 and the terminal device 11 as the highest transmission rate (see (c) in FIG. 7).

Subsequently, the creating unit 44 similarly performs the base station on the basis of the requested minimum rate Rate _MIN12 and the transmission rates Rate ₁ , ₁₂ , Rate ₂ , ₁₂ , and Rate ₃ , ₁₂ in the second row of the information IFO1. 1 and the terminal device 12, between the base station 2 and the terminal device 12, and between the base station 3 and the terminal device 12, wireless communication links MLC2, MLC3, and MLC5 (shown by solid lines) are respectively installed. (See (c) of FIG. 7).

  Hereinafter, similarly, the creation unit 44 establishes wireless communication links MLC6 and MLC7 (shown by solid lines) between the base station 3 and the terminal device 13 and between the base station 3 and the terminal device 14, respectively. The link information LKIF1 is created (see (c) of FIG. 7).

In addition, when the base station to which each terminal apparatus can be connected is determined using the above two conditions (Cnd1) and (Cnd2), the base station that can be connected using the condition (Cnd1) is not determined. Since (Cnd2) is used, it is possible to determine the base station to which each terminal apparatus can be connected using the above two conditions (Cnd1) and (Cnd2) as the required minimum rate Rate _MINi of each terminal apparatus i. This is equivalent to determining a base station capable of wireless communication at a transmission rate as close as possible as a connectable base station and establishing a link between the base station and the terminal device.

  When the creation unit 44 creates the link information LKIF1, the creation unit 44 outputs the created link information LKIF1 to the determination unit 45.

  The determination unit 45 receives the link information LKIF1, and determines the base station to operate and the base station to sleep from the base stations 1 to 3 using the following conditions based on the received link information LKIF1.

  (Cnd3) For a certain terminal device, when it is the only connectable base station, that base station is set as an active base station.

  (Cnd4) Delete the radio communication link with the base station other than the operating base station of the terminal device that can be connected to the base station as the operating base station.

  (Cnd5) A base station that has lost a wireless communication link with a terminal device is defined as a sleep base station.

  (Cnd6) The base station having the most radio communication links with the terminal device is defined as an active base station.

    (Cnd6-1) When there are a plurality of base stations having the same number of wireless communication links, an active base station is selected at random.

    (Cnd6-2) When there are a plurality of base stations having the same number of wireless communication links, a base station with the least power consumption is set as an active base station.

  (Cnd7) The conditions (Cnd4) to (Cnd6) are repeatedly executed until all base stations become active base stations or sleep base stations.

  More specifically, the determination unit 45 detects that the base stations 1 and 3 are the only connectable base stations for the terminal devices 11, 13, and 14 based on the link information LKIF 1, and the condition Using (Cnd3), base stations 1 and 3 are determined to be active base stations (see (d) of FIG. 7).

  Next, the determination unit 45 applies the condition (Cnd4), the terminal device 12 has the wireless communication link MLC2 with the base station 1 which is an operating base station, and is a base station which is an operating base station. 3, the wireless communication link MLC 3 between the base station 2 and the terminal device 12 is deleted. In addition, the determination unit 45 deletes the wireless communication link ML4 between the base station 2 and the terminal device 13 because the terminal device 13 has the wireless communication link MLC6 with the base station 3 which is an operating base station. A wireless communication link MLC6 is established between the base station 3 and the terminal device 13 (see (d) of FIG. 7).

  Subsequently, the determination unit 45 applies the condition (Cnd5) to determine the base station 2 that has lost the wireless communication link with the terminal apparatuses 11 to 14 as a sleep base station (see FIG. 7E). ).

  Furthermore, the determination unit 45 executes the condition (Cnd6). In this case, since the base station 3 has the most three wireless communication links MLC5, MLC6, and MLC7 with the terminal devices 12 to 14, the determination unit 45 satisfies that the base station 3 also satisfies the condition (Cnd6). And the base station 3 is set as an active base station.

  At this stage, since all of the base stations 1 to 3 are active base stations or sleep base stations, the determination unit 45 ends the determination operation of the active base station or the sleep base station, and the operation / sleep list = [ Base station 1: active base station, base station 2: sleep base station, base station 3: active base station] and output to the control means 42.

  In the case where the radio communication system 100 includes base stations 1 to 5 and terminal devices 11 to 16, a method for determining an active base station and a sleep base station will be described.

  FIG. 8 is a conceptual diagram of other stored contents in the storage means 43 shown in FIG. FIG. 9 is a diagram showing another specific example of the connectable list CNLi. Further, FIGS. 10 and 11 are first and second conceptual diagrams for explaining other determination methods of the operating base station and the sleep base station, respectively.

  When the radio communication system 100 includes the base stations 1 to 5 and the terminal devices 11 to 16, the control unit 42 of the control device 20 collects information from the terminal devices 11 to 16 by the same method as described in FIG. The storage unit 43 stores information IFO2 shown in FIG. The contents of the connectable lists CNL11 to CNL16 shown in FIG. 8 are shown in (a) to (f) of FIG. The base stations 1 to 5 are base stations that are woken up by the terminal devices 11 to 16.

  The creation means 44 of the control device 20 reads the information IFO2 shown in FIG. 8 from the storage means 43 in response to the instruction signal DIR2 from the control means 42. Then, the creation unit 44 detects that the terminal device 11 is connectable to the base station 1 based on the connectable list CNL11 (see FIG. 9A) of the information IFO2.

  Further, the creation unit 44 detects that the terminal device 12 is connectable to the base stations 1 to 3 based on the connectable list CNL12 (see FIG. 9B) of the information IFO2.

  Hereinafter, similarly, the creation unit 44 detects that the terminal device 13 is connectable to the base stations 2 and 3 based on the connectable list CNL13 (see FIG. 9C) of the information IFO2, Based on the connectable list CNL14 of the information IFO2 (see FIG. 9D), it is detected that the terminal device 14 can be connected to the base stations 2, 3, and 4, and the connectable list CNL15 of the information IFO2 (see FIG. 9 (see (e)), it is detected that the terminal device 15 is connectable to the base stations 4 and 5, and based on the connectable list CNL16 of the information IFO2 (see (f) in FIG. 9), It is detected that the terminal device 16 can be connected to the base stations 4 and 5.

  Then, the creation unit 44 creates wireless communication links ML11 to ML23 (= indicated by dotted lines) that can be connected between the base stations 1 to 5 and the terminal devices 11 to 16 based on the detection result ( (See (b) of FIG. 10).

Since the base station 1 has wireless communication links ML11 and ML12 that can be connected to the terminal devices 11 and 12, respectively, the creation unit 44 of the control device 20 allows the base station 1 to perform wireless communication with the terminal device 11. Transmission rate Rate ₁ , ₁₁ and the transmission rate Rate ₁ , ₁₂ when the base station 1 performs wireless communication with the terminal device 12.

More specifically, creation means 44, based on the first line of the received signal strength _{RSSI 11,1} information IFO2, the table TBL1 transmission rate _{Rate 1, 11} corresponding to the received signal strength _{RSSI 11,1} Detect by reference. Further, creation means 44, based on the second line of the received signal strength _{RSSI 12,1} information IFO2, referring to detect the transmission rate _{Rate 1, 12} a table TBL1 corresponding to the received signal strength _{RSSI 12,1} To do.

Further, since the base station 2 has the wireless communication links ML13, ML15, and ML17 with the terminal devices 12, 13, and 14, respectively, the creating unit 44 similarly performs the wireless communication between the base station 2 and the terminal device 12. Transmission rate Rate ₂ , ₁₂ when the base station 2 performs wireless communication with the terminal device 13, transmission rate Rate ₂ , ₁₃ when the base station 2 performs wireless communication with the terminal device 13, and transmission rate when the base station 2 performs wireless communication with the terminal device 14 Rate ₂ and ₁₄ are obtained.

Furthermore, since the base station 3 has the wireless communication links ML14, ML16, and ML18 with the terminal devices 12 to 14, respectively, the creating unit 44 similarly performs the wireless communication between the base station 3 and the terminal device 12. transmission rate rate ₃ when performing a transmission rate _{rate 3, 12,} a transmission rate _{rate 3, 13} at which the base station 3 makes a terminal apparatus 13 and the wireless communication base station 3 is a terminal device 14 and wireless communication when _{, 14} are obtained.

Furthermore, since the base station 4 has the wireless communication links ML19, ML20, and ML22 with the terminal devices 14 to 16, respectively, the creating unit 44 similarly performs the wireless communication between the base station 4 and the terminal device 14. transmission rate rate ₄ when performing a transmission rate _{rate 4, 14,} a transmission rate _{rate 4, 15} when the base station 4 performs radio communication with terminal apparatuses 15, the base station 4 is a terminal device 16 and the wireless communication when _{, 16} are obtained.

Furthermore, since the base station 5 has the wireless communication links ML21 and ML23 with the terminal devices 15 and 16, respectively, the creating means 44 is used when the base station 5 performs wireless communication with the terminal device 15 in the same manner. a transmission rate _{rate 5,15,} the base station 5 obtains a transmission rate _{rate 5, 16,} when performing terminal device 16 and wireless communication.

Then, using the above two conditions (Cnd1) and (Cnd2), the creating unit 44 satisfies each of the terminal devices 11 to 16 with the required minimum speed Rate _MINi or as close as possible to the required minimum speed Rate _MINi. A base station capable of wireless communication at a transmission speed is determined as a connectable base station, and a wireless communication link is established between the base stations 1 to 5 and the terminal devices 11 to 16.

More specifically, the creating means 44 performs the base station by the same method as that described in FIG. 7 based on the required minimum rate Rate _MIN11 and the transmission rate Rate ₁ , ₁₁ in the first row of the information IFO2. As a base station to which 1 can be connected, a wireless communication link MLC11 (shown by a solid line) is set up between the base station 1 and the terminal device 11 (see FIG. 10C).

Subsequently, creation unit 44, the required minimum speed _{Rate MIN12} the second row of the information IFO2, transmission rate _Rate 1, _12, Rate 2, _12, based on the _{Rate 3, 12,} in the same manner, the base station 1 and the terminal device 12 and between the base station 2 and the terminal device 12, respectively, wireless communication links MLC12 and MLC13 (shown by solid lines) are set up (see (c) in FIG. 10).

  Hereinafter, in the same manner, the creating means 44 is used between the base station 2 and the terminal device 13, between the base station 3 and the terminal device 13, between the base station 3 and the terminal device 14, and between the base station 4 and the terminal device. 14, wireless communication links MLC15, MLC16, MLC18, MLC19, between the base station 4 and the terminal device 15, between the base station 4 and the terminal device 16, and between the base station 5 and the terminal device 16, respectively. MLC20, MLC22, and MLC23 (shown by solid lines) are stretched to create link information LKIF2 (see (c) of FIG. 10).

When the creation unit 44 creates the link information LKIF2, the created link information LKIF2, the transmission rate Rate _1,11 , Rate _1,12 , Rate _2,12 , Rate _2,13 , Rate _2,14 , Rate _{3, 12} , Rate ₃ , ₁₃ , Rate ₃ , ₁₄ , Rate ₄ , ₁₄ , Rate ₄ , ₁₅ , Rate ₄ , ₁₆ , Rate ₅ , ₁₅ , Rate ₅ , ₁₆ are output to decision means 45.

The determination unit 45 includes link information LKIF2, transmission rates Rate _1,11 , Rate _1,12 , Rate _2,12 , Rate _2,13 , Rate _2,14 , Rate _3,12 , Rate _3,13 , Rate _{3, 14} , Rate ₄ , ₁₄ , Rate ₄ , ₁₅ , Rate ₄ , ₁₆ , Rate ₅ , ₁₅ , Rate ₅ , ₁₆ are received from the creation unit 44. Further, the determination unit 45 reads the information IFO2 from the storage unit 43.

Then, the determination unit 45 detects the power consumption P _TX1 (Rate _1,11 ) corresponding to the transmission rate Rate _1,11 with reference to the table TBL1, and uses the power consumption P _TX1 (corresponding to the transmission rate Rate _1,12. Rate _1,12 ) is detected with reference to the table TBL1.

Then, determination unit 45, information from the first line of data traffic _{B Down1,11} and second line of data traffic _{B Down1,12} of IFO2, power consumption _{P idle1,} the power consumption _{P TX1} that the detected Substituting (Rate _1,11 ) and P _TX1 (Rate _1,12 ) into Equation (1), power consumption P _AP1 in the base station 1 is obtained.

Hereinafter, similarly, the determination unit 45 obtains power consumption P _{AP2 in} the base station ₂ , power consumption P _{AP3 in} the base station 3, power consumption P _{AP4 in the} base station _4, and power consumption P _AP5 in the base station 5.

  Then, the determination unit 45 determines the active base station and the sleep base station from the base stations 1 to 5 using the above conditions (Cnd3) to (Cnd7) based on the received link information LKIF2.

  More specifically, the determination unit 45 detects that the base station 1 is the only connectable base station for the terminal device 11 based on the link information LKIF2, and uses the condition (Cnd3) to Station 1 is determined to be an operating base station (see FIG. 10D).

  Next, the determination unit 45 applies the condition (Cnd4), and since the terminal device 12 has the wireless communication link MLC12 with the base station 1 which is an operating base station, The wireless communication link MLC13 between them and the wireless communication link ML14 between the base station 3 and the terminal device 12 are deleted (see (d) of FIG. 10).

  Thereafter, the determination unit 45 applies the condition (Cnd5), but since there is no base station that has lost the wireless communication link with the terminal device, the determination unit 45 subsequently applies the condition (Cnd6) to The base station 4 having the largest number of wireless communication links is determined as an active base station (see FIG. 11E).

  Furthermore, the determination unit 45 applies the condition (Cnd4) again and deletes the wireless communication links ML17, MLC18, ML21, and MLC23. And the determination means 45 applies conditions (Cnd5) again, and determines the base station 5 as a sleep base station (refer (f) of FIG. 11).

  Thereafter, the determination unit 45 applies the condition (Cnd6) again. In this case, the base stations 2 and 3 each have one wireless communication link MLC15 and MLC16 with the terminal device 13, respectively. Therefore, the determination means 45 applies the condition (Cnd6-1) and randomly determines the base station 2 as an active base station from the base stations 2 and 3.

Further, the determining unit 45 applies the condition (Cnd6-2) to determine the base station 2 with the least power consumption as an operating base station (see (f) in FIG. 11). In this case, the determination unit 45 includes the _total power consumption P _total 1 which is the sum of the power consumption P _AP2 of the base station 2 and the power consumption P _STA13 , ₂ of the terminal device 13, the power consumption P _AP3 of the base station 3, and the terminal A _base that calculates the _total power consumption P _total 2 that is the sum of the power consumption P _STA 13 and 3 of the device 13 and obtains a smaller total power consumption P _total 1 among the _total power consumption P _total 1 and P _total 2. Station 2 is determined as an active base station.

  Subsequently, the determination unit 45 applies the condition (Cnd4) and deletes the wireless communication link MLC16 between the base station 3 and the terminal device 13. And the determination means 45 applies conditions (Cnd5) again, and determines the base station 3 as a sleep base station (refer (g) of FIG. 11).

  At this stage, since all of the base stations 1 to 5 are determined to be active base stations or sleep base stations, the determination unit 45 ends the operation of determining the active base station or sleep base station, and the operation / sleep list = [Base station 1: working base station, base station 2: working base station, base station 3: sleep base station, base station 4: working base station, base station 5: sleep base station] are created and output to the control means 42 To do.

As described above, by applying the conditions (Cnd1) and (Cnd2), the terminal apparatuses 11 to 1K wirelessly transmit to the base stations ₁ to _m at the transmission speed as close as possible to the required minimum speed Rate _MINi. Communication can be performed.

  Further, by applying the condition (Cnd3), the terminal device existing near the end of the area where the base stations 1 to m are arranged is wireless with the base station (any of the base stations 1 to m). Secure communication link.

  Furthermore, by applying the conditions (Cnd4), (Cnd5), and (Cnd6), as many terminal devices as possible establish radio communication links with the operating base stations, and unnecessary base stations sleep. That is, the number of base stations to be operated is minimized.

  Therefore, by applying the conditions (Cnd3) to (Cnd7), it is possible to secure connections to all base stations (active base stations) of the terminal apparatuses 11 to 1K existing in the wireless communication system 100. The minimum necessary base stations can be determined.

  By applying the condition (Cnd6-2), the power consumption in the wireless communication system 100 can be reduced while minimizing the number of base stations to be operated. In this case, since the base station that reduces the total power consumption, which is the sum of the power consumption of the base station to be operated and the power consumption of the terminal device connected to the base station, is determined as the active base station, the wireless communication system 100 The power consumption in can be reduced. As described above, the embodiment of the present invention is characterized in that the base station that consumes less power together with the power consumption of the terminal device is determined as the active base station.

  In the embodiment of the present invention, the determining means 45 uses the following conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), and (Cnd7) to operate base stations and sleep base stations. And may be determined.

  (Cnd3) For a certain terminal device, when it is the only connectable base station, that base station is set as an active base station.

  (Cnd4) Delete the radio communication link with the base station other than the operating base station of the terminal device that can be connected to the base station as the operating base station.

  (Cnd5) A base station that has lost a wireless communication link with a terminal device is defined as a sleep base station.

  (Cnd6A) For a certain terminal device, if it is the only connectable base station, that base station is set as an active base station.

  (Cnd6B) The base station with the fewest radio communication links with the terminal device is set as the sleep base station, and the radio communication link connectable to the base station set as the sleep base station is deleted.

    (Cnd6B-1) When there are a plurality of base stations having the same number of wireless communication links, a sleep base station is selected at random.

    (Cnd6B-2) When there are a plurality of base stations having the same number of wireless communication links, the base station with the largest power consumption is set as the sleep base station.

  (Cnd7) The conditions (Cnd4), (Cnd5), (Cnd6A), and (Cnd6B) are repeatedly executed until all base stations become active base stations or sleep base stations.

  FIG. 12 is a conceptual diagram for explaining still another method for determining an active base station and a sleep base station.

  With reference to FIG. 10 and FIG. 12, a method of determining an active base station and a sleep base station using conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), and (Cnd7) will be described. To do.

  The operation until the link information LKIF2 is created and the base station 1 is determined to be an active base station is as shown in FIG.

  The determination means 45 of the control device 20 determines that the base station 1 is an active base station in FIG. 10 (d), the wireless communication link MLC13 between the base station 2 and the terminal device 12, the base station 3 and the terminal After deleting the wireless communication link ML14 with the device 12, the condition (Cnd5) is applied. However, since there is no base station that has lost the wireless communication link with the terminal device, the determination unit 45 next applies the condition (Cnd6A).

  However, since there is no base station that satisfies the condition (Cnd6A), the determination unit 45 applies the condition (Cnd6B). Of the base stations 2 to 5 that are not determined to be active base stations or sleep base stations at this stage, the base stations 2, 3, and 5 have the same two wireless communication links with the terminal devices. Therefore, for example, the determination unit 45 determines that the base station 3 is a sleep base station by applying the condition (Cnd6B-1), and deletes the wireless communication links MLC16 and MLC18 that can be connected to the base station 3 (FIG. 12). (See (e)).

  Thereafter, the determination unit 45 applies the conditions (Cnd4) and (Cnd5) again, but applies the condition (Cnd6A) because there is no base station that satisfies the conditions (Cnd4) and (Cnd5). And since the base station 2 has the radio | wireless communication link MLC15 unique to the terminal device 13, the determination means 45 determines the base station 2 as an active base station (refer FIG.12 (f)).

  Subsequently, the determining unit 45 applies the condition (Cnd6B), determines the base station 5 with the smallest number of wireless communication links with the terminal device as the sleep base station, and connects the wireless communication links ML21, ML21, Delete MLC23. Then, the determination unit 45 further applies the condition (Cnd4) to delete the wireless communication link MLC19 between the base station 4 and the terminal device 14, and wirelessly communicates between the base station 2 and the terminal device 14. The communication link MLC 17 is set up (see (g) in FIG. 12).

  Thereafter, since there is no base station that satisfies the condition (Cnd5), the determination unit 45 applies the condition (Cnd6A) and determines the base station 4 as an active base station (see (h) in FIG. 12).

  At this stage, since all of the base stations 1 to 5 are determined to be active base stations or sleep base stations, the determination unit 45 ends the operation of determining the active base station or sleep base station, and the operation / sleep list = [Base station 1: working base station, base station 2: working base station, base station 3: sleep base station, base station 4: working base station, base station 5: sleep base station] are created and output to the control means 42 To do.

In addition, in FIG.12 (e), the determination means 45 may determine any of the base stations 2, 3, and 5 as a sleep base station using conditions (Cond6B-2). In this case, determination means 45, the total power consumption _{P total} 3 is the sum of the power consumption _{P STA14,2} power consumption _{P STA13,2} and the terminal device 14 of the power _{P AP2} and the terminal device 13 of the base station 2 , the total power consumption _{P total} 4 is the sum of the power consumption _{P STA14,3} power consumption _{P STA13,3} and the terminal device 14 of the power _{P AP3} and the terminal device 13 of the base station 3, the power consumption of the base station 5 P _AP5 and calculates the total power consumption _{P total} 5 which is the sum of the power consumption _{P STA16,5} power consumption _{P STA15,5} and the terminal device 16 of the terminal device 15, overall power consumption _{P total 3, P} total 4 , P _total 5, the base station 3 that obtains the largest _total power consumption P _total 4 is determined as the sleep base station.

  12 (e), when the base station 4 is determined to be a sleep base station, the determination unit 45 determines that the operation / sleep list = [base station 1: active base station, base station 2: active base station, Base station 3: sleep base station, base station 4: sleep base station, base station 5: active base station], and output to control means 42.

As described above, by applying the conditions (Cnd1) and (Cnd2), the terminal apparatuses 11 to 1K wirelessly transmit to the base stations ₁ to _m at the transmission speed as close as possible to the required minimum speed Rate _MINi. Communication can be performed.

  Further, by applying the condition (Cnd3), a terminal device existing near the end of the area where the base stations 1 to m are arranged can also perform wireless communication with the base station (one of the base stations 1 to m). Secure the link.

  Furthermore, by applying the conditions (Cnd4) and (Cnd5), the wireless communication link with the terminal device is aggregated to the operating base station as much as possible, and unnecessary base stations sleep. That is, the number of base stations to be operated decreases.

  Further, by applying the condition (Cnd6A), the occurrence of an isolated terminal device is prevented. Then, by applying the conditions (Cnd4) and (Cnd5) after applying the condition A (Cnd6A), the wireless communication links with the terminal devices are aggregated to the operating base station as much as possible, and unnecessary base stations sleep. To do. As a result, the number of base stations to be operated further decreases.

  Furthermore, by applying the condition (Cnd6B), a base station having a large number of wireless communication links with the terminal device remains as a candidate for a base station to be operated. Then, by applying the conditions (Cnd4) and (Cbd5) after applying the condition (Cnd6B), the wireless communication links with the terminal devices are aggregated to the operating base station as much as possible, and unnecessary base stations sleep. . As a result, the number of base stations to be operated further decreases.

  Therefore, by applying the conditions (Cnd3) to (Cnd5), (Cnd6A), (Cnd6B), all the base stations (the activated base stations) of the terminal apparatuses 11 to 1K existing in the wireless communication system 100 It is possible to determine the minimum necessary number of base stations for securing the connection to the network.

  By applying the condition (Cnd6B-2), the power consumption in the wireless communication system 100 can be reduced while minimizing the number of base stations to be operated. In this case, since the base station that reduces the total power consumption, which is the sum of the power consumption of the base station to be operated and the power consumption of the terminal device connected to the base station, is finally determined as the operating base station, The power consumption in the communication system 100 can be reduced. As described above, even when the conditions (Cnd3) to (Cnd5), (Cnd6A), and (Cnd6B) are used, it is determined that the base station that consumes less power together with the power consumption of the terminal device is determined as the active base station. Features.

  Further, the determining means 45 determines the operating base station and the sleep base station using the following conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), (Cnd6C), and (Cnd7). May be.

  (Cnd3) For a certain terminal device, when it is the only connectable base station, that base station is set as an active base station.

  (Cnd4) Delete the radio communication link with the base station other than the operating base station of the terminal device that can be connected to the base station as the operating base station.

  (Cnd5) A base station that has lost a wireless communication link with a terminal device is defined as a sleep base station.

  (Cnd6A) For a certain terminal device, if it is the only connectable base station, that base station is set as an active base station.

  (Cnd6B) The base station with the fewest radio communication links with the terminal device is set as the sleep base station, and the radio communication link connectable to the base station set as the sleep base station is deleted.

    (Cnd6B-1) When there are a plurality of base stations having the same number of wireless communication links, a sleep base station is selected at random.

    (Cnd6B-2) When there are a plurality of base stations having the same number of wireless communication links, the base station with the largest power consumption is set as the sleep base station.

  In the (Cnd6C) terminal device, when the operating base station is present closer to the current base station, the terminal device is reconnected to the nearby operating base station.

  (Cnd7) The conditions (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), and (Cnd6C) are repeatedly executed until all base stations become active base stations or sleep base stations.

The determining unit 45 holds in advance a graph indicating the relationship between the received signal strength RSSI _{i, j} and the distance. And the determination means 45 calculates | requires the distance corresponding to the received signal strength RSSI _{i, j} transmitted from each terminal device 11-1K with reference to the graph hold | maintained, and uses the calculated | required distance as a condition. (Cnd6B) is applied.

  FIG. 13 is a conceptual diagram for explaining still another method for determining an operating base station and a sleep base station.

  Referring to FIG. 10 and FIG. 13, the operating base station and the sleep base station are determined using the conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), (Cnd6C), and (Cnd7). How to do will be described.

  The operation until the link information LKIF2 is created and the base station 1 is determined to be an active base station is as shown in FIG.

  The determination means 45 of the control device 20 determines that the base station 1 is an active base station in FIG. 10 (d), the wireless communication link MLC13 between the base station 2 and the terminal device 12, the base station 3 and the terminal After deleting the wireless communication link ML14 with the device 12, the conditions (Cnd5) and (Cnd6A) are applied. However, since there is no base station that satisfies the conditions (Cnd5) and (Cnd6A), the determination unit 45 applies the condition (Cnd6B) next.

  Among the base stations 2 to 5 that are not determined to be active base stations or sleep base stations at this stage, the base stations 2, 3, and 5 have the same two wireless communication links with the terminal devices 13 to 16. .

  Therefore, the determination unit 45 applies the condition (Cnd6B-1) to set the base station 5 as a sleep base station and delete the wireless communication links ML21 and MLC23 (see (e) of FIG. 13).

  After that, the determination unit 45 applies the condition (Cnd6C), but since there is no base station that satisfies the condition (Cnd6C), it applies the conditions (Cnd4) and (Cnd5) again.

  However, since there is no base station that satisfies the conditions (Cnd4) and (Cnd5), the determination unit 45 applies the condition (Cnd6A). In this case, since the base station 4 is the only connectable base station for the terminal device 16, the base station 4 is determined as an active base station (see (f) in FIG. 13).

  And the determination means 45 applies conditions (Cnd6B). In this case, since the base stations 2 and 3 have the same two wireless communication links with the terminal devices 13 and 14, for example, the base station 2 and the sleep base station are applied by applying the condition (Cnd6B-1). The wireless communication links MLC15 and ML17 are deleted (see (g) of FIG. 13).

  Thereafter, the determination unit 45 changes the connection destination of the terminal device 14 from the base station 3 to the base station 4 by applying the condition (Cnd6C) (see (g) of FIG. 13).

  Subsequently, the determination unit 45 applies the conditions (Cnd4) and (Cnd5), but since there is no base station that satisfies the conditions (Cnd4) and (Cnd5), the determination unit 45 applies the condition (Cnd6A) to The operating base station is determined (see (h) in FIG. 13).

  At this stage, since all of the base stations 1 to 5 are determined to be active base stations or sleep base stations, the determination unit 45 ends the operation of determining the active base station or sleep base station, and the operation / sleep list = [Base station 1: working base station, base station 2: sleep base station, base station 3: working base station, base station 4: working base station, base station 5: sleep base station] are created and output to the control means 42 To do.

  The determination unit 45 may determine any of the base stations 2, 3, and 5 as a sleep base station using the condition (Cond6B-2) in FIG. In this case, the determination unit 45 determines the base station 5 as a sleep base station by the method described in FIG.

  As described above, the conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), (Cnd6C), and (Cnd7) are the conditions (Cnd3), (Cnd4), (Cnd5), and (Cnd6A). ), (Cnd6B), and (Cnd7), the same as when applying the conditions (Cnd3), (Cnd4), (Cnd5), (Cnd6A), (Cnd6B), and (Cnd7) As many wireless communication links as possible are concentrated in the operating base station as much as possible, unnecessary base stations sleep, and the number of base stations to be operated decreases. Then, by further applying the condition (Cnd6C), the wireless communication link with the terminal device is further collected in the operating base station. As a result, the number of base stations to be operated is minimized.

  Therefore, by applying the conditions (Cnd3) to (Cnd5), (Cnd6A), (Cnd6B), and (Cnd6C), connections to all base stations of the terminal apparatuses 11 to 1K existing in the wireless communication system 100 are established. The minimum necessary base station for securing can be determined.

  Others are the same as when the conditions (Cnd3) to (Cnd5), (Cnd6A), and (Cnd6B) are applied.

  FIG. 14 is a flowchart for explaining the operation in the radio communication system 100.

  Referring to FIG. 14, when operation in radio communication system 100 is started, terminal apparatuses 11 to 1K transmit wake-up signals (step S1), and base stations 1 to m among base stations 1 to M are transmitted. Receives the wake-up signal and activates it, and transmits the activation signal DRV1 to the control device 20 (step S2).

  And control device 20 receives starting signal DRV1 from base stations 1-m (Step S3), and detects that base stations 1-m started.

Thereafter, the base stations 1 to m broadcast a beacon frame (step S4), and the terminal apparatuses 11 to 1K perform a background scan to receive the beacon frame and detect the received signal strength RSSI _{i, j} (step S4). 5).

Then, the terminal devices 11 to 1K create a connectable list CNLi indicating the base stations to which the terminal devices 11 to 1K can connect based on the received beacon frame, and calculate the power consumption P _{STAi, j} by the above-described method (step) S6). Then, the terminal apparatuses 11 to 1 </ b> K have their own requested minimum rate Rate _MINi , the connectable list CNLi, the received signal strength RSSI _{i, j} , and the power consumption P _{STAi, j} packet = [MACaddi: Rate _MINi / CNLi / RSSI]. _{i, j} / _{PSTAi, j} ] is transmitted to the base station having the largest received signal strength RSSI _{i, j} (step S7).

Each base station 1-m receives the packet = [MACaddi: Rate _MINi / CNLi / RSSI _{i, j} / P _{STAi, j} ] (step S8), and MACaddi: Rate _MINi / CNLi / RSSI _{i, j} / P _{STAi. , J} and the data communication amount B _{downj, i} are transmitted to the control device 20 (step S9).

The control device 20 receives MACaddi: Rate _MINi / CNLi / RSSI _{i, j} / P _{STAi, j} and data communication amount B _{downj, i} (step S10), and MACaddi: Rate _MINi / CNLi / RSSI _{i, j} Based on / P _{STAi, j} and data communication amount _{Bdownj, i} , the operating base station and the sleep base station are determined by the method described above (step S11).

Then, the control device 20 transmits the operation / sleep list L _DS including the operation base station, the sleep base station, and the power consumption P _APj to the base stations 1 to _m (step S12).

The base station 1~m is configured to receive the operation / sleep list _{L DS,} it transmits the operation / sleep list _{L DS} to the terminal device 11～1K (step S13), and the terminal device 11～1K is run / sleep list L _DS is received (step S14).

On the other hand, the base station 1~m is up or sleeps in accordance running / sleep list _{L DS} (Step S15). The terminal device 11~1K, based on the operation / sleep list L _DS, as well as detecting the operating base station, the received signal strength RSSI i, in _j the largest operating base station or power consumption lowest operating base station The connection destination is changed (step S16). When the connection destination is changed to an operating base station that consumes the least amount of power, each terminal device 11 to 1K becomes an operating base station that has the least total power consumption, which is the sum of its own power consumption and that of the operating base station. Change the connection destination.

  And a series of operation | movement is complete | finished after step S15, S16.

The control unit 42 of the control device 20, in step S12, and transmits the operation / sleep list _{L DS} to the base station 1 to m. Then, the base station 1~m Since up or sleep based on the operation / sleep list _{L DS,} is the control unit 42 transmits the operation / sleep list _{L DS} to the base station 1~m, the determining means 45 This corresponds to controlling the base stations 1 to m so that the base station determined as the operating base station operates and the base station determined as the sleep base station by the determining means 45 sleeps.

As described above, in the embodiment of the present invention, the control device 20 includes the active base station and the sleep base for the base stations 1 to m waked up by the terminal devices 11 to 1K among the base stations 1 to M. The operation / sleep list including the determined operation base station and sleep base station is transmitted to the base stations 1 to m and the terminal devices 11 to 1K. Then, the base stations 1 to m operate or sleep based on the operation / sleep list received from the control device 20, and the terminal devices 11 to 1K receive among the operation base stations based on the operation / sleep list. The connection destination is changed to an operating base station with a high signal strength RSSI _{i, j} or an operating base station with low power consumption.

  Therefore, the minimum necessary base station to which all the terminal devices 11 to 1K can be connected can be determined from the activated base stations 1 to m.

  FIG. 15 is a flowchart for explaining the detailed operation of step S11 shown in FIG.

Referring to FIG. 15, after step S <b> 10 shown in FIG. 14, the creation unit 44 of the control device 20 is based on the connectable list CNLi, the requested minimum rate Rate _MINi, and the transmission rate Rate _{j, i} in the base stations 1 to _{m. Thus} , a base station that satisfies the required minimum rate Rate MINi of each of the terminal devices 11 to _1K is set as a connectable base station and a link is established (step S111).

Thereafter, when there is no base station that satisfies the required minimum rate Rate _MINi , the creating unit 44 creates a link by setting a base station that can obtain the highest transmission rate as a connectable base station, and creates link information LKIF (step S112). . Then, the creation unit 44 outputs the link information LKIF to the determination unit 45.

  The determination unit 45 receives the link information LKIF, and determines whether or not the condition (Cnd3) is satisfied based on the received link information LKIF (step S113).

  When it is determined in step S113 that the condition (Cnd3) is satisfied, the determination unit 45 sets the only connectable base station for a certain terminal device as an active base station (step S114).

  On the other hand, when it is determined in step S113 that the condition (Cnd3) is not satisfied, the series of operations proceeds to step S115.

  Then, after step S114 or when it is determined in step S113 that the condition (Cnd3) is not satisfied, the determining unit 45 determines whether or not the condition (Cnd4) is satisfied (step S115).

  When it is determined in step S115 that the condition (Cnd4) is satisfied, the determining unit 45 sets a wireless communication link with a base station other than the operating base station of the terminal device that can be connected to the base station serving as the operating base station. Delete (step S116).

  On the other hand, when it is determined in step S115 that the condition (Cnd4) is not satisfied, the series of operations proceeds to step S117.

  Then, after step S116 or when it is determined in step S115 that the condition (Cnd4) is not satisfied, the determining unit 45 determines whether or not the condition (Cnd5) is satisfied (step S117).

  When it is determined in step S117 that the condition (Cnd5) is satisfied, the determination unit 45 sets the base station that has lost the wireless communication link with the terminal device as the sleep base station (step S118).

  On the other hand, when it is determined in step S117 that the condition (Cnd5) is not satisfied, the series of operations proceeds to step S119.

  Then, after step S118 or when it is determined in step S117 that the condition (Cnd5) is not satisfied, the determining unit 45 determines whether or not the condition (Cnd6) is satisfied (step S119).

  When it is determined in step S119 that the condition (Cnd6) is satisfied, the determination unit 45 sets the base station having the most wireless communication links with the terminal device as the active base station (step S120). In this case, if there are a plurality of base stations having the same number of wireless communication links with the terminal device, the determining unit 45 randomly determines an operating base station. In addition, when there are a plurality of base stations having the same number of wireless communication links with the terminal device, the determination unit 45 sets the base station with the minimum power consumption as the active base station.

  Then, after step S120 or when it is determined in step S119 that the condition (Cnd6) is not satisfied, the determination unit 45 determines whether or not all base stations are determined to be active base stations or sleep base stations. (Step S121).

  When it is determined in step S121 that all base stations are not determined to be active base stations or sleep base stations, the series of operations returns to step S115, and in step S121, all base stations are Steps S115 to S121 described above are repeatedly executed until it is determined that the sleep base station has been determined.

  If it is determined in step S121 that all base stations have been determined to be active base stations or sleep base stations, the series of operations proceeds to step S12 illustrated in FIG.

  FIG. 16 is a flowchart for explaining another detailed operation of step S11 shown in FIG.

  The flowchart shown in FIG. 16 is the same as the flowchart shown in FIG. 15 except that steps S119 and S120 in the flowchart shown in FIG. 15 are replaced with steps S119A, S119B, S120A, and S120B.

  Referring to FIG. 16, determination means 45 sequentially executes steps S111 to S118 described above after step S10 shown in FIG.

  Then, when it is determined in step S117 that the condition (Cnd5) is not satisfied, or after step S118, the determination unit 45 determines whether or not the condition (Cnd6A) is satisfied (step S119A).

  When it is determined in step S119A that the condition (Cnd6A) is satisfied, the determination unit 45 sets the only connectable base station as an active base station for a certain terminal device (S119B).

  On the other hand, when it is determined in step S119A that the condition (Cnd6A) is not satisfied, the series of operations proceeds to step S120A.

  Then, when it is determined in step S119A that the condition (Cnd6A) is not satisfied, or after step S119B, the determination unit 45 determines whether or not the condition (Cnd6B) is satisfied (step S120A).

  When it is determined in step S120A that the condition (Cnd6B) is satisfied, the determining unit 45 sets the base station having the smallest number of wireless communication links with the terminal device as the sleep base station, and the base station as the sleep base station The wireless communication link connectable to is deleted (step S120B). In this case, if there are a plurality of base stations having the same number of wireless communication links with the terminal device, the determining unit 45 randomly determines a sleep base station. Further, when there are a plurality of base stations having the same number of wireless communication links with the terminal device, the determining unit 45 sets the base station with the highest power consumption as the sleep base station.

  On the other hand, when it is determined in step S120A that the condition (Cnd6B) is not satisfied, the series of operations proceeds to step S121.

  Then, after step S120B or when it is determined in step S120A that the condition (Cnd6B) is not satisfied, step S121 described above is executed.

  Thereafter, in step S121, the above-described steps S115 to S118, S119A, S119B, S120A, S120B, and S121 are repeatedly executed until it is determined that all the base stations have been determined to be active base stations or sleep base stations.

  When it is determined in step S121 that all base stations have been determined to be active base stations or sleep base stations, the series of operations proceeds to step S12 illustrated in FIG.

  FIG. 17 is a flowchart for explaining still another detailed operation of step S11 shown in FIG.

  The flowchart shown in FIG. 17 is the same as the flowchart shown in FIG. 16 except that steps S120C and S120D are inserted between step S120B and step S121 of the flowchart shown in FIG.

  With reference to FIG. 17, the determination means 45 performs step S111-S118, S119A, S119B, S120A, S120B mentioned above sequentially after step S10 shown in FIG.

  Then, when it is determined in step S120A that the condition (Cnd6B) is not satisfied, or after step S120B, the determination unit 45 determines whether or not the condition (Cnd6C) is satisfied (step S120C).

  When it is determined in step S120C that the condition (Cnd6C) is satisfied, the determination unit 45 changes the connection destination to an active base station closer to the current base station (step S120D).

  On the other hand, when it is determined in step S120C that the condition (Cnd6C) is not satisfied, the series of operations proceeds to step S121.

  When it is determined in step S120C that the condition (Cnd6C) is not satisfied, or after step S120D, step S121 described above is executed.

  Thereafter, the above-described steps S115 to S118, S119A, S119B, S120A, S120B, S120C, S120D, and S121 are repeatedly executed until it is determined in step S121 that all the base stations have been determined to be active base stations or sleep base stations. Is done.

  When it is determined in step S121 that all base stations have been determined to be active base stations or sleep base stations, the series of operations proceeds to step S12 illustrated in FIG.

  As described above, by executing the flowchart shown in FIG. 14 (including any of the flowcharts shown in FIGS. 15 to 17), the base station waked up by the terminal devices 11 to 1K among the base stations 1 to M. 1 to m are activated, and the necessary minimum number of base stations for securing wireless communication links with the terminal apparatuses 11 to 1K are determined from the activated base stations 1 to m, and the necessity Only a minimum number of base stations operate, and unnecessary base stations sleep (see step S15).

  Therefore, all the radio communications of the terminal devices 11 to 1K existing in the radio communication system 100 can be ensured and the power consumption in the radio communication system 100 can be reduced.

Further, since the terminal apparatuses 11 to 1K change the connection destination to the base station having the largest received signal strength RSSI _{i, j} among the minimum necessary number of base stations (see step S16), Wireless communication can be performed stably while reducing power consumption.

  Furthermore, since the terminal devices 11 to 1K change the connection destination to the base station with the least power consumption among the necessary minimum number of base stations (see step S16), the power consumption in the wireless communication system 100 is further reduced. it can.

  FIG. 18 is a flowchart for explaining an operation when the terminal device is detached from the wireless communication system 100.

  The flowchart shown in FIG. 18 is the same as the flowchart shown in FIG. 14 except that steps S1 to S4 in the flowchart shown in FIG. 14 are replaced with steps S21 to S27.

  Referring to FIG. 18, at least one of base stations 1 to m detects that a packet is not received for a certain period from a terminal device (at least one of terminal devices 11 to 1K) connected to itself. Thus, it is detected that the terminal device has left the wireless communication system 100 (step S21).

  Then, at least one of the base stations 1 to m transmits a leave notification SEP indicating that the terminal device has left to the control device 20 (step S22).

  The control device 20 receives the leave notification SEP (step S23), and generates and transmits an instruction signal DIR1 for instructing the background scan (step S24).

  The base stations 1 to m receive the instruction signal DIR1 from the control device 20, and the received instruction signals DIR1 are already connected to the base stations 1 to m (terminal devices 11 to 1K). , Terminal devices other than the detached terminal device, N = 1, 2, 3,...) (Step S25).

  The terminal devices 11 to 1N receive the instruction signal DIR1 (step S26) and execute a background scan (step S27).

  Thereafter, the above-described steps S5 to S16 are sequentially executed.

In this case, the link information LKIF created by the creation unit 44 of the control device 20 based on the minimum required rate Rate _MINi , the received signal strength RSSI _{i, j} and the connectable list CNLi transmitted from the terminal devices 11 to 1N is “updated”. Configure link information.

  Further, the connectable list CNLi transmitted from the terminal devices 11 to 1N constitutes an “updated connectable list”.

  18 describes the case where the terminal device has left the wireless communication system 100. However, even when a new terminal device enters the wireless communication system 100, the active base station and the sleep base are in accordance with the flowchart shown in FIG. The station is determined. In this case, “leave” in steps S21, S22, and S23 shown in FIG. 18 may be read as “entry”.

As described above, when some of the terminal devices 11 to 1K leave the wireless communication system 100, the terminal devices 11 to 1N remaining in the wireless communication system 100 perform background scanning after the removal. Requested minimum rate Rate _MINi / Connectable list CNLi / Received signal strength RSSI _{i, j} / Power consumption PSTA _{i, j} is transmitted again to the control device 20, and the control device 20 requests the minimum required rate Rate after the terminal device leaves. _{Based on MINi} / connectable list CNLi / received signal strength RSSI _{i, j} / power consumption PSTA _{i, j} , an active base station and a sleep base station are determined. Then, the base station 1~m is up or sleep based on the operation / sleep list L _DS after the terminal device is disconnected, the terminal device 11~1N the operation after the terminal device is disconnected / sleep list L _DS To determine the base station to connect to.

  Therefore, even when the terminal device leaves the radio communication system 100, the minimum necessary number for securing radio communication links with the terminal devices 11 to 1N among the activated base stations 1 to m. Only the minimum necessary number of base stations operate and unnecessary base stations sleep (see step S15 in FIG. 18).

  Therefore, all the radio communications of the terminal devices 11 to 1N existing in the radio communication system 100 can be secured, and the power consumption in the radio communication system 100 can be reduced.

Also, the terminal apparatuses 11 to 1N change the connection destination to the base station having the largest received signal strength RSSI _{i, j} among the necessary minimum number of base stations (see step S16 in FIG. 18). Wireless communication can be stably performed while reducing power consumption in the system 100.

  Furthermore, since the terminal apparatuses 11 to 1N change the connection destination to the base station with the least power consumption among the necessary minimum number of base stations (see step S16 in FIG. 18), the power consumption in the wireless communication system 100 Can be further reduced.

  Note that the operation of the wireless communication system 100 when an operating base station (at least one of the base stations 1 to m) receives a connection request using a probe request frame from a terminal device (any of the terminal devices 11 to 1K). Is executed according to the flowchart shown in FIG.

  In this case, in step S1, the terminal device (at least one of the terminal devices 11 to 1K) transmits a connection request using a probe request frame, and in step S2, the operating base station (at least one of the base stations 1 to m) is transmitted. When the host system 143 receives a connection request based on the probe request frame from the wireless communication module 141, the host system 143 generates a connection request signal CDM and transmits it to the control device 20. In step S3, the control device 20 A signal CDM is received. Thereafter, steps S4 to S16 described above are sequentially executed.

As described above, when the operating base station receives the connection request by the probe request frame, the terminal apparatuses 11 to 1N in the wireless communication system 100 receive the requested minimum rate Rate _MINi / connectable list CNLi / received signal strength RSSI _{i. , J} / power consumption PSTA _{i, j} is transmitted to the control device 20, and the control device 20 transmits the request minimum rate Rate _MINi / connectable list CNLi / received signal strength RSSI _i after the connection request by the probe request frame is transmitted. _{, J} / power consumption PSTA _{i, j} , the active base station and the sleep base station are determined. Then, the base stations 1 to m operate or sleep based on the operation / sleep list L _DS after the connection request by the probe request frame is transmitted, and the terminal devices 11 to 1N transmit the connection request by the probe request frame. to determine the connection destination of the base station based on the operation / sleep list L _DS after it has been.

  Therefore, even when the terminal device transmits a connection request using a probe request frame, the minimum necessary for securing a wireless communication link with the terminal devices 11 to 1N among the activated base stations 1 to m. A sufficient number of base stations are determined, and only the necessary minimum number of base stations are operated, and unnecessary base stations sleep (see step S15 in FIG. 14).

  As a result, all the radio communications of the terminal apparatuses 11 to 1N existing in the radio communication system 100 can be ensured and the power consumption in the radio communication system 100 can be reduced.

  In addition, the same effects as described above can be obtained.

  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 control device and a wireless communication system including the control device.

  1 to M base station, 11 to 1K terminal device, 20 control device, 21 and 110 antenna, 22 and 141 wireless communication module, 23 wake-up signal transmitter, 24 and 143 host system, 30 wired cable, 41 receiving means, 42 Control means, 43 storage means, 44 creation means, 45 determination means, 46 transmission means, 100 wireless communication system, 120 switch, 121 switch, 122, 123 terminal, 130 wakeup device, 131 wakeup signal receiver, 132 wake Up determination device, 140 main device, 142 wired communication module, 150 power supply.

Claims (10)

Among M (M is an integer of 2 or more) base stations existing in the wireless communication system, m (m is 1 ≦ m ≦ 1) woken up by K (K is an integer of 2 or more) terminal devices. Receiving means for receiving an activation signal indicating that the m number of base stations have been activated, or a connection request signal indicating that a connection request has been received, from an integer satisfying M);
A connectable list indicating base stations to which the K terminal devices can be connected, K received signal strengths in the K terminal devices, and K requests that are the minimum transmission rates required by each terminal device. Storage means for storing the minimum speed;
Based on the connectable list, the K received signal strengths, and the K requested minimum speeds, all of the K terminal devices are self-requested minimums in response to the activation signal or the connection request signal. Creating means for creating link information indicating a connection relationship between the m base stations and the K terminal devices for wireless communication with any of the m base stations at a transmission speed as close as possible to the speed; ,
Based on the link information created by the creating means, a first base station that has only a single wireless communication link with a first terminal device that is any one terminal device is used as a working base station. A second condition for deleting a link with a base station other than the operating base station of a terminal device that can be connected to the base station as a condition, an operating base station, a wireless communication link with the terminal device The third condition is set such that the base station that does not have the sleep base station is the third condition, and the fourth condition that the base station having the most radio communication links with the terminal device is the active base station, and the fourth condition is sequentially executed. Determining means for repeatedly executing the second condition from 2 to determining the active base station and the sleep base station from the m base stations;
Control means for controlling the m base stations so that the base station determined as the active base station by the determining means operates, and the sleep base station determined by the determining means sleeps. A control device provided.   When the fourth condition is executed, and when there are a plurality of base stations having the same number of radio communication links with the terminal device, the determining unit includes power consumption in one base station, and the one base station The control apparatus according to claim 1, wherein a base station having a minimum sum of power consumption in all terminal apparatuses having a wireless communication link is determined as the active base station. Among M (M is an integer of 2 or more) base stations existing in the wireless communication system, m (m is 1 ≦ m ≦ 1) woken up by K (K is an integer of 2 or more) terminal devices. Receiving means for receiving an activation signal indicating that the m number of base stations have been activated, or a connection request signal indicating that a connection request has been received, from an integer satisfying M);
A connectable list indicating base stations to which the K terminal devices can be connected, K received signal strengths in the K terminal devices, and K requests that are the minimum transmission rates required by each terminal device. Storage means for storing the minimum speed;
Based on the connectable list, the K received signal strengths, and the K requested minimum speeds, all of the K terminal devices are self-requested minimums in response to the activation signal or the connection request signal. Creating means for creating link information indicating a connection relationship between the m base stations and the K terminal devices for wireless communication with any of the m base stations at a transmission speed as close as possible to the speed; ,
Based on the link information created by the creating means, a first base station that has only a single wireless communication link with a first terminal device that is any one terminal device is used as a working base station. A second condition for deleting a link with a base station other than the operating base station of a terminal device that can be connected to the base station as a condition, an operating base station, a wireless communication link with the terminal device The base station that has the least wireless communication link with the third condition as a sleep base station and a base station that does not have a sleep base station is defined as the sleep base station, and can be connected to the base station as the sleep base station A fourth condition for deleting a radio communication link from the link information is sequentially executed, and the second to fourth conditions are repeatedly executed, so that the m base stations and the three base stations Determining means for determining a base station,
Control means for controlling the m base stations so that the base station determined as the active base station by the determining means operates, and the sleep base station determined by the determining means sleeps. A control device provided.   When the fourth condition is executed, and when there are a plurality of base stations having the same number of radio communication links with the terminal device, the determining unit includes power consumption in one base station, and the one base station The control apparatus according to claim 3, wherein a base station having a maximum sum of power consumption in all terminal apparatuses having a wireless communication link between them is determined as the sleep base station.   When the base station having a link with a second terminal device which is an arbitrary one terminal device is located farther than the base station determined to be the active base station, the determining means The fifth condition for switching the connection destination of the terminal device to the base station determined to be the active base station is executed after the fourth condition, and the second to fifth conditions are repeatedly executed, The control device according to claim 4, wherein the active base station and the sleep base station are determined from the base stations.   The determination means, when executing the fourth condition, when there are a plurality of base stations having the same number of radio communication links with the terminal device, the base station randomly selected from the plurality of base stations is operated. The control device according to claim 1, wherein the control device is determined as a base station or the sleep base station. The storage means is configured such that when the new terminal device enters the wireless communication system or the terminal device leaves the wireless communication system, the K terminal devices are N (N = 1, 2, 3,. ..) When the number of terminal devices is reached, the base stations to which the N terminal devices can be connected are indicated, and the updated connectable list, the N received signal strengths, and the N terminal devices Memorize N requested minimum speeds at
Based on the updated connectable list, the N received signal strengths, and the N requested minimum rates, the creating means can make all of the N terminal devices have their own requested minimum rates. Creating updated link information indicating a connection relationship between the m base stations and the N terminal devices for wireless communication with any of the m base stations at a close transmission rate;
The determining means sequentially executes the first to fourth conditions and repeatedly executes the second to fourth conditions on the basis of the updated link information, from the m base stations to the operating base. A station and the sleep base station,
The control means controls the n base stations so that the base station determined as the active base station by the determining means operates and the base station determined as the sleep base station by the determining means sleeps. The control device according to claim 1 or 3.   The creating means sets a base station that satisfies the required minimum speed of each terminal device as a connectable base station, and when there is no base station that satisfies the required minimum speed, the base station that can obtain the highest transmission speed is connected. The control apparatus according to any one of claims 1 to 7, wherein the link information or the update link information is created by using a possible base station. M (M is an integer of 2 or more) base stations;
K (K is an integer of 2 or more) terminal devices each accessing one of the M base stations;
Among the M base stations, an active base station and a sleep base station are determined from m base stations (where m is an integer satisfying 1 ≦ m ≦ M) woken up by the K terminal devices. A control device that controls the m base stations so that the operating base station and the determined base station operate, and the sleep base station and the determined base station sleep;
The said control apparatus is a radio | wireless communications system which consists of a control apparatus of any one of Claims 1-8.   Each of the K terminal devices changes a connection destination to an active base station having the highest received signal strength with the self base station or an active base station having the lowest power consumption among the active base stations determined by the control device. The wireless communication system according to claim 9.

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