JP2010278763A - Base station equipment - Google Patents

Abstract

To provide a base station apparatus capable of normal operation and reducing power consumption even when a terminal station operating in a power saving mode is connected.
The present invention relates to a base station apparatus of a wireless LAN system, a terminal management unit 12 for managing the operating state of each accommodated terminal station, and a beacon signal for each accommodated terminal station. The MAC unit 15 that transmits and the operation state managed by the terminal management unit 12 indicate the transition state to the power saving mode of each accommodated terminal station and the data transmitted and received between each terminal station And a power saving management unit 11 that determines a beacon signal transmission cycle of the MAC unit 15 based on the presence / absence state of the MAC unit 15.
[Selection] Figure 1

Description

  The present invention relates to a base station apparatus for a wireless LAN system.

  In a wireless LAN system, since a terminal station device (hereinafter referred to as a terminal station) is battery-driven, it is one of the important issues to realize low power consumption. For example, in the following Non-Patent Document 1, a power saving mode is defined as an operation mode for realizing power saving of a terminal station.

  In the power saving mode defined in Non-Patent Document 1 below, the terminal station is activated at every DTIM (Delivery Traffic Indication Message) interval and is transmitted from a base station apparatus (hereinafter referred to as a base station). A beacon signal as a signal is received, and it is confirmed whether data addressed to the terminal station is held in the base station. The DTIM interval is information (set in the beacon signal) notified by a beacon signal. If the data addressed to the terminal station is not held, the sleep is immediately performed (transition to the state in which the transmission / reception operation is not executed). If the data addressed to the terminal station is held, the data is received from the base station. Sleep. In the wireless LAN system defined in Non-Patent Document 1 below, power saving of the terminal station is realized by performing such control.

On the other hand, considering the reduction of CO ₂ screamed in recent years, it is essential to realize power saving even in network devices. By the way, with the increase in capacity of wireless LANs, MIMO (Multiple Input Multiple Output) technology using a plurality of antennas is also widely used, but with this, power consumption of base stations is regarded as a problem. It is becoming. That is, until now, it was sufficient to design the system mainly considering the power consumption reduction on the terminal station side, but in the future, it is necessary to consider the power consumption reduction on the base station side as well.

  Here, Patent Document 1 below describes a technique for realizing power consumption reduction on the base station side. Specifically, in an integrated base station having a plurality of base stations in a casing, depending on the number of terminal stations connected to the integrated base station, a part of the plurality of base stations is stopped. As a result, power consumption is reduced.

Japanese Patent Laid-Open No. 2004-165953

“IEEE Std 802.11.-2007, Part 11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”

  However, the base station described in Patent Document 1 does not consider the case where the terminal station operates in the power saving mode of the wireless LAN described above. Therefore, a terminal station that operates in the power saving mode cannot be recognized as a connected terminal station, and the base station that should not be in the operation stopped state is also in the operation stopped state, that is, the terminal station that operates in the power saving mode. There is a problem that normal operation cannot be guaranteed when is connected.

  The present invention has been made in view of the above, and provides a base station apparatus that can operate normally even when a terminal station that operates in a power saving mode is connected and that can reduce power consumption. With the goal.

  In order to solve the above-mentioned problems and achieve the object, the present invention is a base station apparatus of a wireless LAN system, comprising terminal management means for managing the operating state of each accommodated terminal station, The beacon transmission means for transmitting a beacon signal to each terminal station, the operation state managed by the terminal management means, the transition state to the power saving mode of each terminal station accommodated, and Power saving management means for determining a beacon signal transmission period of the beacon transmission means based on the presence / absence state of data to be transmitted / received to / from each terminal station.

  According to the present invention, the base station apparatus monitors the operation state of each terminal station, whether all the terminal stations are operating in the power saving mode, and whether there is data to be transmitted to and received from the terminal stations, Since the transmission interval of the beacon signal is controlled based on the confirmation result, it is possible to achieve power saving control.

FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a wireless communication system including a base station apparatus according to the present invention. FIG. 2 is a diagram for explaining the operation of the base station according to the first embodiment. FIG. 3 is a diagram for explaining the operation of the base station according to the second embodiment. FIG. 4 is a diagram for explaining the operation of the base station according to the third embodiment.

  Embodiments of a base station apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a wireless communication system including a base station apparatus according to the present invention, and also illustrates a configuration example of the base station apparatus.

  The wireless communication system of the present embodiment includes a wireless LAN base station (hereinafter referred to as a base station) 1, a wireless LAN terminal (hereinafter referred to as a terminal station) 2, and a presence information management server 3. 1 and presence information management server 3 are configured to communicate via wired network 100. In the configuration of FIG. 1, the terminal station 2 accommodated in the base station 1 is one station, but a plurality of stations may exist. In addition, the terminal station 2 has a function of operating in the above-described power saving mode. When connected to the base station 1, the terminal station 2 is in power saving mode or non-consumption according to the instruction (setting of the operation mode) from the user. Operates in power mode (normal mode). Although details will be described later, the presence information management server 3 manages presence information, which is one of the information used in the power saving control in the base station 1.

  As illustrated, the base station 1 includes a power saving management unit 11, a terminal management unit 12, a time management unit 13, a wired I / F unit 14, a MAC unit 15, a PHY unit 16, and an RF unit 17. .

  The power saving management unit 11 determines whether to shift the base station 1 to the power consumption reduction mode based on the information about the connected terminal station 2 managed by the terminal management unit 12.

  The terminal management unit 12 identifies each terminal station by acquiring the MAC address of the currently connected terminal station 2 from the MAC unit 15 and manages the connection state of each terminal station and information related to the operation of the terminal station, for example, Whether the terminal station supports the power saving mode, whether it is operating in the power saving mode (power saving mode ON / OFF status), received power status, statistical information (current and past data transfer status), etc. Then, these pieces of information are managed as terminal information.

  The time management unit 13 performs time management, and notifies the current time when receiving an inquiry from the power saving management unit 11.

  The wired I / F unit 14 is an interface on the wired network side and has a termination function such as 802.3 Ethernet (registered trademark).

  The MAC unit 15 controls the MAC layer and provides a CSMA / CA function, a beacon transmission / reception function, a data transfer function to the wired I / F unit 14, and the like. The MAC unit 15 constitutes a beacon transmission unit.

  The PHY unit 16 controls the physical layer. The RF unit 17 performs transmission / reception processing of radio signals.

  An operation example of the base station 1 in the wireless communication system having such a configuration will be described with reference to FIG. FIG. 2 is a diagram for explaining the operation of the base station 1 according to the first embodiment, and shows an example of the transmission timing of the beacon signal in the base station 1.

  In the operation illustrated in FIG. 2, when the base station 1 detects that all of the following conditions are satisfied, the base station 1 transmits the beacon signal, which is broadcast information, by expanding the transmission interval to the DTIM interval (consumption) (Power reduction mode)

<Condition # 1> All terminals (all connected terminals) in operation are operating in the power saving mode.
<Condition # 2> There is no transmission / reception traffic (data to be transmitted / received) with any terminal station of all terminal stations.

  In FIG. 2, a beacon signal is transmitted at a timing when a solid line arrow from the base station 1 to each terminal station (terminal stations 2-1, 2-2,..., 2-N) is described. The beacon signal is not transmitted at the described timing. That is, in this example, until the timing of the second solid arrow shown from the left in the figure, the beacon signal transmission interval is operated without expanding to the DTIM interval, and then the mode is shifted to the power consumption reduction mode and the beacon signal transmission interval is reached. Is spreading. Note that, when not in the power consumption reduction mode, the base station 1 transmits a beacon signal even at a timing at which a dotted arrow is described (transmits a beacon signal according to a beacon period).

  The control shown in FIG. 2 is realized by the operations of the power saving management unit 11 and the terminal management unit 12. When these specific operations are shown, the terminal management unit 12, as already described, identifies the identification information (for example, MAC address) of each terminal station connected to the base station 1 and the operation of each connected terminal station. Information about the terminal is acquired and managed as terminal information. Further, the power saving management unit 11 acquires terminal information from the terminal management unit 12 at a predetermined timing, and checks whether or not the above conditions # 1 and # 2 are satisfied based on this terminal information. If the condition is satisfied, the MAC unit 15 is instructed to thin out the beacon signal. When the MAC unit 15 receives an instruction to thin out a beacon signal from the power saving management unit 11, the MAC unit 15 performs transmission control so that the beacon signal is transmitted at the DTIM interval set in the beacon signal. For example, if the DTIM interval is 2, a beacon signal is transmitted at a period twice as long as the beacon interval (see FIG. 2).

  Note that the beacon signal may be transmitted at an integer multiple of the DTIM interval. Further, instead of shifting to the power consumption reduction mode when both of the above two conditions are satisfied, the shift may be made when it is detected that at least one of the two conditions is satisfied.

  As described above, the base station according to the present embodiment monitors the operating state of each connected terminal station (within the area), and all the terminal stations are operating in the power saving mode in accordance with the wireless LAN standard. When it is detected that there is no transmission / reception traffic with any terminal station, the transmission interval of the beacon signal is changed to the DTIM interval. Thereby, power consumption in the base station can be reduced. Further, since the transmission interval is changed when each terminal station is operating in the power saving mode, no abnormal operation occurs in the terminal station.

Embodiment 2. FIG.
Next, the base station according to the second embodiment will be described. The configurations of the radio communication system and the base station are the same as those in Embodiment 1 (see FIG. 1). Therefore, this embodiment will also be described with reference to FIG.

  FIG. 3 is a diagram for explaining the operation of the base station 1 according to the second embodiment, and shows an example of the transmission timing of the beacon signal in the base station 1. In the operation shown in FIG. 3, the base station 1 satisfies the following condition # 3 in addition to the conditions # 1 and # 2 used when executing the operation described in the first embodiment (see FIG. 2). Use to determine whether to shift to the power consumption reduction mode.

<Condition # 1> All terminals (all connected terminals) in operation are operating in the power saving mode.
<Condition # 2> There is no transmission / reception traffic (data to be transmitted / received) with any terminal station of all terminal stations.
<Condition # 3> A specific time set in advance.

  In FIG. 3, as in FIG. 2, a beacon signal is transmitted from the base station 1 to each terminal station at a timing indicated by a solid line arrow, and a beacon signal is transmitted at a timing indicated by a dotted line arrow. It shows no.

  The control shown in FIG. 3 is realized by the operations of the power saving management unit 11, the terminal management unit 12, and the time management unit 13. These specific operations are shown below.

  The operation of the terminal management unit 12 is the same as that in the case of performing the control in the first embodiment. The time management unit 13 uses a GPS (Global Positioning System), for example, to adjust its own clock, or to synchronize time via the wired network 100 using NTP (Network Time Protocol), SNTP (Simple Network Time Protocol), or the like. Use the function to adjust the clock you have. The power saving management unit 11 acquires terminal information from the terminal management unit 12 at a predetermined timing, inquires the time management unit 13 about the current time, and based on the acquired terminal information and the current time, the condition # 1 Whether or not to # 3 is satisfied is checked, and if all the conditions are satisfied, the MAC unit 15 is instructed to thin out the beacon signal. When the MAC unit 15 receives a beacon signal thinning instruction from the power saving management unit 11, the MAC unit 15 performs transmission control so that the beacon signal is transmitted at a DTIM interval. Here, the “specific time” of the condition # 3 may be, for example, a night or a holiday when the number of connected terminals is assumed to be small, and this is set by the administrator of the base station.

  As in the case of executing the operation shown in FIG. 2 (the operation described in the first embodiment), the beacon signal may be transmitted at a cycle that is an integral multiple of the DTIM interval. Condition # 3 is mandatory, but when at least one of conditions # 1 and # 2 is satisfied (that is, when conditions # 1 and # 3 are satisfied, or conditions # 2 and # 3 are satisfied) Case), the mode may be shifted to the power consumption reduction mode. Since other parts are the same as those in the first embodiment, description thereof is omitted.

  As described above, in the base station according to the present embodiment, the operation described in the first embodiment is performed at a preset specific time. Thereby, control according to the present time can be realized.

Embodiment 3 FIG.
Next, the base station according to the third embodiment will be described. The configurations of the radio communication system and the base station are the same as those in Embodiment 1 (see FIG. 1). Therefore, this embodiment will also be described with reference to FIG.

  FIG. 4 is a diagram for explaining the operation of the base station 1 according to the third embodiment, and shows an example of the transmission timing of the beacon signal in the base station 1. In the operation shown in FIG. 4, the base station 1 satisfies the following condition # 4 in addition to the conditions # 1 to # 3 used when executing the operation described in the second embodiment (see FIG. 3). Use to determine whether to shift to the power consumption reduction mode.

<Condition # 1> All terminals (all connected terminals) in operation are operating in the power saving mode.
<Condition # 2> There is no transmission / reception traffic (data to be transmitted / received) with any terminal station of all terminal stations.
<Condition # 3> A specific time set in advance.
<Condition # 4> The presence information regarding the user of each terminal station indicates “all absent”.

  Here, presence information is information indicating whether or not the user of each terminal station is in a state where the terminal station can be used. For example, if the base station 1 is installed in a certain company, It is assumed that the information is managed by the presence information management server 3 in another system different from the wireless communication system including the base station 1, such as employee entry / exit information, attendance / exit information, and employee ID position detection function. “Attendance” indicates that the user can use the terminal station (near the terminal station), and “absent” indicates that the user cannot use the terminal station (near the terminal station) Not).

  In FIG. 4, as in FIG. 2, the beacon signal is transmitted at the timing indicated by the solid line arrow from the base station 1 to each terminal station, and the beacon signal is transmitted at the timing indicated by the dotted arrow. It shows no.

  The control shown in FIG. 4 is realized by the operations of the power saving management unit 11, the terminal management unit 12, and the time management unit 13. These specific operations are shown below.

  In addition to the operations in the case of performing the control in the first and second embodiments, the terminal management unit 12 sends each terminal station (terminal stations 2-1, 2-2, ...) from the presence information management server 3 at a predetermined timing. , 2-N), the presence information indicating whether the user is present is acquired and held. The operation of the time management unit 13 is the same as that in the case of performing the control of the second embodiment. The power saving management unit 11 obtains terminal information and presence information from the terminal management unit 12 at a predetermined timing, obtains current time information from the time management unit 13, and consumes based on the obtained information. It is determined whether to shift to the power reduction mode. If it is determined to shift to the low power consumption mode, the MAC unit 15 is instructed to thin out the beacon signal. When the MAC unit 15 receives a beacon signal thinning instruction from the power saving management unit 11, the MAC unit 15 performs transmission control so that the beacon signal is transmitted at a DTIM interval.

  The power saving management unit 11 is based on determining that “transition to the power consumption reduction mode” is performed when all of the above-described conditions # 1 to # 4 are satisfied. If conditions # 1 to # 3 are satisfied or condition # 4 is satisfied, “transfer” is determined. (Modification 2) If conditions # 1, # 3, and # 4 are satisfied, “transfer” is determined. (Modification 3) When the conditions # 2, # 3, and # 4 are satisfied, it may be determined that “migrate”. The combination of these conditions may be configured to be appropriately changeable according to the installation environment of the base station 1.

  In addition, the terminal management unit 12 does not acquire and store the presence information from the presence information management server 3, but the power saving management unit 11 directly acquires the presence information from the presence information management server 3. It may be.

  Also, the beacon signal may be transmitted at a cycle that is an integral multiple of the DTIM interval, as in the case of executing the operation shown in FIGS. 2 and 3 (the operation described in the first and second embodiments). Since other parts are the same as those in the first or second embodiment, description thereof is omitted.

  As described above, in the base station according to the present embodiment, in addition to the determination condition used in the operation described in the second embodiment, the operation control is performed in consideration of the determination condition using presence information. . As a result, the conditions for shifting to the power consumption reduction mode can be set in detail according to the installation environment of the base station.

  In addition, in addition to the control operations described above (the control operations described in the present embodiment and the first and second embodiments), the base station 1 may execute the following control operations together. Good. Further power saving can be realized by executing the following control operations together.

  For example, the terminal management unit 12 also manages the signal reception power from each connected terminal station 2, and the power saving management unit 11 determines the beacon signal based on the signal reception power managed by the terminal management unit 12. The transmission power may be controlled. In this case, when it is determined that the signal reception power from each terminal station 2 is all equal to or higher than a certain level, it is determined that all the terminal stations 2 exist in the vicinity of the base station 1 and the beacon signal Reduce transmission power. This control can be performed regardless of whether or not the transmission period of the beacon signal is changed to the DTIM interval. That is, even if the beacon signal is transmitted in a normal cycle (= beacon cycle), if it is determined that all the terminal stations 2 are located in the vicinity of the base station 1, the transmission power of the beacon signal Can be lowered.

  The power saving management unit 11 is in a low power consumption state with respect to the MAC unit 15, the PHY unit 16, and the RF unit 17 during a period from when a beacon signal is transmitted at a certain timing until the next beacon signal is transmitted You may make it instruct | indicate so that it may become. In this case, in response to an instruction from the power saving management unit 11, the PHY unit 16 and the RF unit 17 transition to a dormant state in which power supply is stopped. The return to the normal operation state also follows the instruction from the power saving management unit 11. Further, when receiving an instruction from the power saving management unit 11, the MAC unit 15 activates only the beacon transmission / reception function and does not operate the other functions. This control is performed in a state where the transmission period of the beacon signal is changed to the DTIM interval. This control can be combined with the control operations described in the first and second embodiments and the present embodiment, and the transmission power control operation of the beacon signal (the signal reception power managed by the terminal management unit 12). (Beacon signal transmission power control operation based on).

  As described above, the base station apparatus according to the present invention is useful for a wireless LAN base station apparatus, and is particularly suitable for a base station apparatus that accommodates a terminal station that supports a power saving mode.

1 Wireless LAN base station (base station)
2 Wireless LAN terminal (terminal station)
3 presence information management server 11 power saving management unit 12 terminal management unit 13 time management unit 14 wired I / F unit 15 MAC unit 16 PHY unit 17 RF unit 100 wired network

Claims (9)

A base station apparatus for a wireless LAN system,
Terminal management means for managing the operating state of each terminal station accommodated;
Beacon transmission means for transmitting a beacon signal to each terminal station accommodated;
Based on the transition state to the power saving mode of each terminal station accommodated and the presence / absence state of data to be transmitted / received to / from each terminal station indicated by the operation state managed by the terminal management means A power saving management means for determining a beacon signal transmission period of the beacon transmitting means;
A base station apparatus comprising: The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode and any of the terminal stations 2. The base station apparatus according to claim 1, wherein the beacon transmission unit is controlled to transmit a beacon signal at a DTIM interval when it is detected that there is no data to be transmitted / received during the period. The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode, or the terminal station 2. The base according to claim 1, wherein the beacon transmitting unit is controlled to transmit a beacon signal at a DTIM interval when it is detected that there is no data to be transmitted to or received from any of the bases. Station equipment. The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode and any of the terminal stations The beacon transmitting means is controlled to transmit a beacon signal at a DTIM interval when it is detected that there is no data to be transmitted / received during the period and the current time is a preset time. The base station apparatus according to claim 1, wherein: The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode, or the terminal station The beacon transmission means is controlled to transmit a beacon signal at a DTIM interval when it is detected that there is no data to be transmitted / received to / from any of these and the current time is a preset time The base station apparatus according to claim 1, wherein: When the terminal station is used only for users belonging to a specific organization, and the organization manages the presence status information of the user on the server,
The terminal management means accesses the server at a predetermined timing and manages the presence status information obtained in the operation state,
The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode and any of the terminal stations In addition, it is detected that there is no data to be transmitted / received during the period, and further, when the current time is a preset time and it is detected that all users of each terminal station are absent, The base station apparatus according to claim 1, wherein the beacon transmitting unit is controlled to transmit a beacon signal. When the terminal station is used only for users belonging to a specific organization, and the organization manages the presence status information of the user on the server,
The terminal management means accesses the server at a predetermined timing, and manages the information on the presence status obtained in the operation state,
The power saving management means confirms the operation state managed by the terminal management means at a predetermined timing, and all the terminal stations accommodated are operating in the power saving mode, or the terminal station When it is detected that there is no data to be transmitted to or received from any of the above, and when it is detected that the current time is a preset time and all the users of each terminal station are absent, The base station apparatus according to claim 1, wherein the beacon transmitting unit is controlled to transmit a beacon signal at a DTIM interval. When the power saving management unit instructs the beacon transmission unit to transmit a beacon signal at a DTIM interval, the RF unit that performs radio signal transmission / reception processing and a PHY unit that controls the physical layer To stop operation,
When receiving the instruction to transmit the beacon signal at the DTIM interval, the beacon transmission means starts the beacon signal transmission operation at the instructed interval and stops functions other than the beacon signal transmission operation. The base station apparatus according to any one of claims 2 to 7. When receiving a signal from the terminal station, the terminal management means manages the reception power information included in the operation state,
The power saving management means is configured to transmit the beacon signal with a low transmission power in a state in which it is detected that the signal reception power from each terminal station is not less than a certain value. The base station apparatus according to claim 1, wherein the transmission unit is controlled.

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