JP4897716B2 - Wireless communication system, operation management server device, and wireless base station control method - Google Patents

Description

  In a wireless communication system such as a public wireless LAN in which a plurality of wireless base stations (access points: AP) exist, the present invention relates to a wireless communication system, an operation management server device, and a wireless communication system that control transmission power and a transmission antenna pattern of each wireless base station The present invention relates to a radio base station control method.

  2. Description of the Related Art Conventionally, there is a method in which a plurality of radio base stations of a radio communication system are arranged in a plane to cover a relatively wide area and a station placement design is performed by a careful site survey (Non-patent Document 1). This method measures the reception level characteristics and throughput characteristics within and without line of sight for each radio base station, and evaluates the interference area to optimally design the channel arrangement and the inter-base station distance that do not cause interference. It is.

On the other hand, there is a method called AutoCell in which radio base stations and mobile radio terminals exchange radio wave reception status and interference status, and based on the information, the radio base station performs autonomous distributed control of transmission power (non-patent document). Reference 2).
"Research on Base Station Design Method for Multiple High-Speed Wireless LANs in University Campus," Musashi Institute of Technology, Faculty of Environment and Information Sciences, Journal of Information Media Center 2005.4 No. 6, pp.54-60 Autocell- The Self-Organizing WLAN, Propagate Networks, Inc. 2003

  In the station placement design method based on the site survey of Non-Patent Document 1, the time required for station placement design becomes enormous, and there is a problem that the time and cost for transmission power control of a plurality of wireless base stations constituting the wireless LAN increase. It was.

  In addition, there may be no mobile wireless terminal to be connected in a public area such as an airport or an underground mall. In that case, in the AutoCell method of Non-Patent Document 2, there is no means for grasping the reception status or the like of the radio wave transmitted from the radio base station, and autonomous distributed control of transmission power is not possible. That is, there is a problem that the transmission power of the radio base station cannot be updated, and the area where radio waves interfere increases. FIG. 10 shows a state in which a mobile radio terminal (STA) 11 is present in the radio area and the transmission power of each radio base station (AP) 12 is appropriately controlled. Circles indicate areas where radio waves transmitted by each radio base station reach, and circles overlap each other indicate interference areas where radio waves from multiple radio base stations interfere, and the interference areas are minimized Recognize. FIG. 11 shows a state in which there is no mobile radio terminal (STA) in the radio area, the transmission power of each radio base station (AP) 12 cannot be controlled, and the interference area is large.

  By the way, in a public area such as an airport or an underground shopping area, for example, a sensor node equipped with a temperature sensor or the like may be arranged, and a sensor network connected to a sensor server via a sensor GW (gateway) may be installed. Such a sensor node transmits / receives a radio signal to / from the sensor GW, and may receive a radio signal transmitted from a radio base station of a public wireless LAN.

  The present invention acquires the reception status of radio waves transmitted from each radio base station using a fixed radio terminal of another radio communication system such as a sensor network, and transmits the transmission power of each radio base station based on the reception status An object of the present invention is to provide a radio communication system, an operation management server apparatus, and a radio base station control method for controlling a transmission antenna pattern.

In the first invention, a plurality of radio base stations and mobile radio terminals constitute a radio communication network, and the transmission power or transmission of each radio base station according to the reception status of the transmission signal of each radio base station in each mobile radio terminal In a wireless communication system for controlling an antenna pattern, unlike a mobile wireless terminal of a wireless communication network, a fixed wireless terminal that is fixedly present in a wireless area of each wireless base station and can receive a transmission signal of the wireless base station The reception status of the transmission signal of each radio base station in the fixed radio terminal is acquired, and for each radio base station, the transmission signal of the radio base station to be controlled and the other one radio base station exceed the predetermined reception power The number of fixed wireless terminals that are simultaneously receiving the data is counted, and when the number is equal to or greater than the threshold, the non-transmission is performed so that the transmission power from the wireless base station toward the other wireless base station is reduced. The transmission power and transmitting antenna pattern of the base station and a management server for centralized control.

In the second invention, a plurality of radio base stations and mobile radio terminals constitute a radio communication network, and the transmission power or transmission of each radio base station is determined according to the reception status of the transmission signal of each radio base station in each mobile radio terminal. In a wireless communication system for controlling an antenna pattern, unlike a mobile wireless terminal of a wireless communication network, a fixed wireless terminal that is fixedly present in a wireless area of each wireless base station and can receive a transmission signal of the wireless base station The fixed radio terminal that acquires the reception status of the transmission signal of each radio base station in the fixed radio terminal and receives the transmission signal of the radio base station to be controlled with a predetermined reception power or more for each radio base station And the number Q of fixed wireless terminals that simultaneously receive transmission signals of the radio base station and other radio base stations at a predetermined reception power or higher, and the ratio Q / P of the numbers is a threshold value. The radio base station reduces the transmission power of the radio base station when T1 or more, and increases the transmission power of the radio base station when the ratio Q / P of the number is equal to or less than a threshold T2 (T1> T2). And an operation management server for centrally controlling the transmission power of the network.

According to a third aspect of the present invention, a plurality of radio base stations and mobile radio terminals constitute a radio communication network, and the operation management server determines whether each radio base station has a transmission signal received by each radio base station according to the reception status of each radio base station. In the radio base station control method of the radio communication system for controlling the transmission power and the transmit antenna pattern, unlike the mobile radio terminal of the radio communication network, the radio base station transmission is fixedly present in the radio area of each radio base station. There is a fixed wireless terminal capable of receiving a signal, and the operation management server acquires the reception status of the transmission signal of each wireless base station in the fixed wireless terminal, and for each wireless base station, the wireless base station to be controlled and Aggregate the number of fixed wireless terminals that are simultaneously receiving a transmission signal of another wireless base station at a predetermined reception power or higher, and if the number is equal to or greater than a threshold, One of to reduce the transmission power to the radio base station direction, centralized control transmit power and transmit antenna pattern of the radio base station.

According to a fourth aspect of the present invention, a radio communication network is configured by a plurality of radio base stations and mobile radio terminals, and an operation management server is provided for each radio base station according to the reception status of transmission signals of each radio base station in each mobile radio terminal. In the radio base station control method of the radio communication system for controlling the transmission power and the transmit antenna pattern, unlike the mobile radio terminal of the radio communication network, the radio base station transmission is fixedly present in the radio area of each radio base station. There are fixed wireless terminals capable of receiving a signal, the operation management server acquires the reception status of the transmission signal of each radio base station in the fixed wireless terminal, for each radio base station, of the radio base station to be controlled The number P of fixed wireless terminals receiving a transmission signal with a predetermined reception power or more and the transmission signals of the radio base station and other radio base stations are simultaneously received with a predetermined reception power or more. When the ratio Q / P of the number of fixed wireless terminals is equal to or greater than the threshold T1, the transmission power of the radio base station is reduced, and the ratio Q / P of the number is equal to or less than the threshold T2 (T1> T2 ), The transmission power of the radio base station is centrally controlled so as to increase the transmission power of the radio base station.

  The present invention uses a fixed radio terminal that is fixedly present in the radio area of each radio base station, unlike a mobile radio terminal of a radio communication network, and receives a transmission signal of each radio base station in each fixed radio terminal To get. As a result, even when there is no mobile radio terminal in the radio area of each radio base station, a dead zone or an overlap zone of the transmission signal of each radio base station is detected, and the transmission power and transmission antenna pattern of each radio base station are determined. It can be controlled accurately.

(Basic configuration of wireless communication system of the present invention)
FIG. 1 shows a basic configuration of a wireless communication system of the present invention.
In the figure, an area of the wireless communication system of the present invention includes a mobile wireless terminal (STA) 11 and a plurality of wireless base stations (AP1 to AP5) 12, a plurality of sensor nodes (SN) 21 and sensor gateways (fixed wireless terminals). S-GW) 22 is arranged.

  The AP 12 that accommodates the STA 11 is connected to the operation management server 14 and the external network 15 via the HUB 13 to configure a wireless communication network. Each AP 12 has a function as a bridge device for connecting the STA 11 accommodated therein to the network 15. Each AP 12 has a function of controlling transmission power and a transmission antenna pattern so that an interference area is minimized in accordance with an instruction from the operation management server 14.

  On the other hand, the S-GW 22 that accommodates each SN 21 is connected to the sensor server 24 and the external network 15 via the HUB 23 to constitute a sensor network. Each S-GW 22 functions as a bridge device that relays communication between the SN 21 and the sensor server 24, has a sensor, and has a function as a sensor node. The sensor server 24 and the operation management server 14 are connected via the network 15 and the HUBs 13 and 23.

  In such a configuration, the STA 11 and the SN 21 receive the transmission signal of the AP 12, the STA 11 notifies the operation management server 14 of the AP identifier (AP address) and the received power via the AP 12, and the SN 21 detects the S-GW 22 and the sensor. An AP identifier (AP address) and received power are notified to the operation management server 14 via the server 24. The operation management server 14 acquires the reception power for each AP notified from the STA 11 and the reception power for each AP notified from the SN 21 and performs centralized control so that the transmission power or the transmission antenna pattern of each AP 12 is optimized. . In detail, it demonstrates with reference to drawings of each embodiment shown below.

  Note that the present invention is based on the assumption that an SN 21 serving as a substitute for the STA 11 exists, and the STA 11 does not necessarily exist in the area of each AP 12. Therefore, in the following description, for the sake of simplicity, the example in which the STA 11 accommodated by the AP 12 is omitted and only the reception status of the SN 21 is used is shown. However, the operation management server 14 displays the reception status of the STA 11 and the reception status of the SN 21 in the same row It is assumed that optimal control of the transmission power and transmission antenna pattern of each AP 12 is performed.

(First embodiment)
FIG. 2 shows a sequence example of the first embodiment of the wireless communication system of the present invention.
In the figure, the configuration of this sequence example is a simplification of the basic configuration of the wireless communication system shown in FIG. 1, and the operation management server 14 and AP 12 constituting the wireless communication network and the sensor server 24 constituting the sensor network. This will be described using S-GW22 and SN21.

  The SN 21 and the S-GW 22 can receive the signal frequency of the wireless communication network and have a function of receiving and decoding the transmission signal of the AP 12. The sensor server 24 has a function of managing the position of each SN 21 and S-GW 22 and converting the sensor ID into sensor position information. The operation management server 14 grasps the range in which the radio waves of each AP 12 reach based on the position of each SN 21 and S-GW 22, the received power, and the position of each AP 12. The AP 12 is configured to freely change the antenna pattern using an array antenna or the like, and is configured to control the transmission power and the transmission antenna pattern in accordance with an instruction from the operation management server 14.

  In such a configuration, the AP 12 transmits a beacon signal including an AP address. SN 21 and S-GW 22 receive and decode a beacon signal transmitted by AP 12, and store the AP address and its received power value. The operation management server 14 transmits an SN 21 reception status report request to the sensor server 24. The sensor server 24 transmits this reception status report request to the SN 21 via the S-GW 22. In response to the reception status report request, the SN 21 transmits a reception status report including the sensor ID, the stored AP address, and the received power value to the sensor server 24 via the S-GW 22. When the reception status report of the SN 21 is input, the sensor server 24 converts the sensor ID into sensor position information, and transmits it to the operation management server 14 as a reception status report including the AP address and the reception power value.

  The operation management server 14 operates according to the processing procedure shown in FIG. Note that the physical positional relationship between each AP 12 and each SN 21 and S-GW 22 is grasped using, for example, GPS information. First, sensor position information, AP address, and received power value are collected from SN 21 and S-GW 22 (S11). The received power from each AP 12 at the position of each SN 21 and S-GW 22 is compared with the assumed value (S12). Next, in each AP 12, the transmission power and the transmission antenna pattern of each AP 12 are reset so as to reduce the transmission power in the direction higher than the assumed value and increase the transmission power in the direction lower than the assumed value (S13).

(Second Embodiment)
FIG. 4 shows a sequence example of the second embodiment of the wireless communication system of the present invention.
In the figure, the configuration of this sequence example is the same as that of the first embodiment shown in FIG. In the first embodiment, the SN 21 has a function of receiving the transmission signal of the AP 12, decoding the frame configuration including the AP address, and measuring the reception power for each AP address. The difference is that a detectable signal is transmitted from the AP 12.

  The SN 21 receives the transmission signal of the AP 12, and stores an identifier (for example, binary code) representing the AP and its received power value. The operation management server 14 transmits an SN 21 reception status report request to the sensor server 24. The sensor server 24 transmits this reception status report request to the SN 21 via the S-GW 22. In response to the reception status report request, the SN 21 transmits a reception status report including the sensor ID, the stored identifier, and the received power value to the sensor server 24 via the S-GW 22. When the reception status report of the SN 21 is input, the sensor server 24 converts the sensor ID into sensor position information, and transmits it to the operation management server 14 as a reception status report including an identifier and a received power value. Similarly, reception status reports are collected from the other SN 21 and S-GW 22. Here, since the identifier uniquely corresponds to each radio base station, the operation management server 14 operates in accordance with the same processing procedure as that of the first embodiment shown in FIG. 3, and retransmits the transmission power and transmission antenna pattern of each AP 12. Set.

(Third embodiment)
FIG. 5 shows a sequence example of the third embodiment of the wireless communication system of the present invention.
In the first and second embodiments, the operation management server 14 grasps the range in which the radio waves of each AP 12 reach according to the processing procedure shown in FIG. 3 from the received power of each AP 12 at the position of the SN 21, and transmits the transmission power of each AP 12. And the transmission antenna pattern was reset. Therefore, it is necessary to grasp the physical positional relationship between each AP 12 and each SN 21 using, for example, GPS information.

  In this embodiment, the operation management server 14 aggregates the AP address (or identifier) and received power of each AP 12 reported from each SN 21 and S-GW 22, and simultaneously receives the radio waves of other APs for each AP. Depending on the number of overlapping SNs, the transmission power and transmission antenna pattern in the other AP direction are controlled for the AP, so that the number of overlapping SNs, that is, the overlap between the AP and other AP areas is minimized. It is characterized by controlling to. In this embodiment, since it is not necessary to grasp the physical positional relationship between each AP 12 and each SN 21, position information of each SN 21 is not necessary, and it is sufficient if there is a sensor ID necessary for counting overlapping SNs.

FIG. 6 shows a processing procedure of the operation management server 14 in the third embodiment.
In FIG. 6, the operation management server 14 collects AP addresses or identifiers and received power from the SNs 21 and S-GWs 22 according to the sequence example shown in FIG. 5 and tabulates them (S21). Next, for APn (n is 1, 2,..., N−1), the radio waves of the APn and other APm (m is n + 1, n + 2,..., N) are simultaneously received at a predetermined reception power or higher. The number Q (n) of overlapping SNs is determined (S22), and Q (n) is compared with the threshold T (S23). Here, if Q (n) ≧ T, it is determined that the area in the APn to APm direction is wide, and the transmission antenna pattern and the transmission power are re-established so as to reduce the transmission power in the APm direction with respect to APn. Set (S24). If Q (n) <T, it is determined that the area in the direction from APn to APm is appropriate, no instruction is issued to APn, and the transmission antenna pattern and transmission power are maintained. In all combinations of APn and other APm (where m> n), the control of the transmission power in the APm direction from APn is repeated, and when it is finished, the number of APs received at a predetermined reception power or higher is The transmission antenna pattern and transmission power of the AP are reset so that the transmission power of the AP closest to the SN of 0 in the SN direction is increased (S25).

FIG. 7 shows a control example of the operation management server 14 in the third embodiment.
In FIG. 7, if the threshold T = 3, the number of overlapping SNs for AP1 and AP2 is Q (1) = 2, so AP1 maintains the transmission antenna pattern and transmission power in the AP2 direction. Next, since the number of overlapping SNs for AP1 and AP3 is Q (1) = 5, AP1 reduces the transmission power in the direction of AP3. Such control is performed in AP1 and AP4, AP1 and AP5, AP2 and AP3, AP2 and AP4, AP2 and AP5, AP3 and AP4, AP3 and AP5, AP4 and AP5. And when the radio wave of any AP is not received like SN21, the transmission power from the nearest AP5 to the direction of SN21 is increased.

(Fourth embodiment)
In the fourth embodiment, as in the sequence example of the third embodiment shown in FIG. 5, the operation management server 14 determines the AP address or identifier and the received power of each AP 12 reported from each SN 21 and S-GW 22. Tally. The difference from the third embodiment is that, for each AP, the ratio of the number of SNs receiving the radio waves of the AP and the number of overlapping SNs simultaneously receiving the radio waves of the AP and other APs depends on the ratio. Thus, control is performed so that only the transmission power is increased or decreased for the AP, and control is performed so that the number of overlapping SNs, that is, the overlapping of the areas of each AP 12 is minimized. In this embodiment, since it is not necessary to grasp the physical positional relationship between each AP 12 and each SN 21, position information of each SN 21 is not necessary, and it is sufficient if there is a sensor ID necessary for counting overlapping SNs.

FIG. 8 shows a processing procedure of the operation management server 14 in the fourth embodiment.
In FIG. 8, the operation management server 14 collects AP addresses or identifiers and received power from the SNs 21 and S-GWs 22 according to the sequence example shown in FIG. 5 and sums them up (S31). Next, for APn (n is 1, 2,..., N), the number P (n) of received SNs that receive the radio waves of the APn at a predetermined reception power or higher, and radio waves of other APs among them. Also, the number Q (n) of duplicate SNs received at the same time is determined (S32). Next, Q (n) / P (n) is calculated and compared with the first threshold value T1 and the second threshold value T2 (T1> T2) (S33).

  Here, if Q (n) / P (n) ≧ T1, it is determined that the APn area is wide, and the APn is reset to reduce the transmission power (S34). If Q (n) / P (n) ≦ T2, it is determined that the area of APn is narrow, and the transmission power is reset with respect to APn (S35). If T2 ≦ Q (n) / P (n) ≦ T1, it is determined that the APn area is appropriate, and no instruction is issued to APn, and the transmission power is maintained. Thus, when the resetting of the transmission power for APn is completed, the same process is repeated for the other APs, the transmission power for all APs is reset, and the process is terminated.

FIG. 9 shows a control example of the operation management server 14 of the fourth embodiment.
In FIG. 9, the number of received SNs in each area of AP1 to AP5 is P (1) = 10, P (2) = 8, P (3) = 10, P (4) = 8, P (5) = 2. And are counted. Further, there are two reception SNs common to AP1 and AP2, five reception SNs common to AP1 and AP3, and the number of overlapping SNs in AP1 Q (1) = 7 is counted. Similarly, the number of overlapping SNs in AP2 Q (2) = 3, the number of overlapping SNs in AP3 Q (3) = 7, and the number of overlapping SNs in AP4 Q (4) = 3 , The number of overlapping SNs in AP5 B (5) = 0. Here, if T1 = 0.6 and T2 = 0.1, AP1 and AP3 are Q / P = 7/10, so the transmission power is reduced, and AP2 and AP4 are Q / P = 3/8, so the transmission power is reduced. AP5 is controlled to increase transmission power because Q / P = 0/2.

  In addition, although this embodiment assumes the case where transmission power control with respect to all AP is collectively performed based on the total result of the received power collected from each SN21 and S-GW22, each SN21 and S-GW are assumed. A method may be used in which transmission power control for one AP is performed based on the total result of received power collected from the GW 22, and transmission power control for each AP is sequentially performed while reflecting the result.

  In any case, since it is not necessary to grasp the physical positional relationship between the AP and the SN in this embodiment, in the sequence example illustrated in FIG. The operation management server 14 can add up the number P of received SNs and the number Q of duplicate SNs for each AP 12 using the sensor ID as it is. Then, the operation management server 14 can control the transmission power of the AP based on the comparison result between the Q / P and the threshold values T1 and T2 for each AP. Further, in this embodiment, only the transmission power of each AP is controlled, and control of the transmission antenna pattern is unnecessary, so an omni antenna may be used as the AP antenna.

The figure which shows the basic composition of the radio | wireless communications system of this invention. The sequence example of 1st Embodiment of the radio | wireless communications system of this invention is shown. The flowchart which shows the process sequence of the operation management server 14 in 1st Embodiment. The sequence example of 2nd Embodiment of the radio | wireless communications system of this invention is shown. The sequence example of 3rd Embodiment of the radio | wireless communications system of this invention is shown. The flowchart which shows the process sequence of the operation management server 14 in 3rd Embodiment. The figure explaining the example of control of the operation management server 14 in 3rd Embodiment. The flowchart which shows the process sequence of the operation management server 14 in 4th Embodiment. The figure explaining the control example of the operation management server 14 in 4th Embodiment. The figure which shows the example of transmission power control of the wireless base station in the conventional wireless communication system. The figure which shows the transmission power control example (control impossible state) of the wireless base station in the conventional wireless communication system.

Explanation of symbols

11 Mobile radio terminal (STA)
12 Radio base station (AP)
13 HUB
14 Operation management server 15 Network 21 Sensor node (SN)
22 Sensor gateway (S-GW)
23 HUB
24 sensor server

Claims (4)

A radio that configures a radio communication network with a plurality of radio base stations and mobile radio terminals, and controls the transmission power or transmission antenna pattern of each radio base station according to the reception status of the transmission signal of each radio base station in each mobile radio terminal In a communication system,
Unlike a mobile radio terminal of the radio communication network, a fixed radio terminal that is fixedly present in a radio area of each radio base station and can receive a transmission signal of the radio base station;
The reception status of the transmission signal of each radio base station in the fixed radio terminal is acquired, and for each radio base station, the transmission signal of the radio base station to be controlled and one other radio base station are received in a predetermined manner Count the number of fixed wireless terminals simultaneously receiving at or above the power, and when the number is equal to or greater than the threshold, reduce the transmission power from the wireless base station toward the other wireless base station. An operation management server that centrally controls the transmission power and transmission antenna pattern of the station ;
Wireless communication system comprising the. A radio that configures a radio communication network with a plurality of radio base stations and mobile radio terminals, and controls the transmission power or transmission antenna pattern of each radio base station according to the reception status of the transmission signal of each radio base station in each mobile radio terminal In a communication system,
Unlike a mobile radio terminal of the radio communication network, a fixed radio terminal that is fixedly present in a radio area of each radio base station and can receive a transmission signal of the radio base station;
The reception status of the transmission signal of each radio base station in the fixed radio terminal is acquired, and for each radio base station, the transmission signal of the radio base station to be controlled is received at a predetermined reception power or higher The number P of wireless terminals and the number Q of fixed wireless terminals that simultaneously receive transmission signals of the wireless base station and other wireless base stations at a predetermined reception power or higher are tabulated, and the ratio Q / P of the numbers is The radio base station is configured to reduce the transmission power of the radio base station when the threshold T1 is equal to or higher than the threshold T1, and to increase the transmission power of the radio base station when the ratio Q / P of the number is equal to or lower than the threshold T2 (T1> T2). An operation management server that centrally controls the transmission power of stations
Wireless communication system comprising the. A radio communication network is configured with a plurality of radio base stations and mobile radio terminals, and the operation management server determines the transmission power and transmission antenna pattern of each radio base station according to the reception status of the transmission signal of each radio base station in each mobile radio terminal. In a radio base station control method of a radio communication system for controlling
Unlike the mobile radio terminal of the radio communication network, there is a fixed radio terminal that is fixedly present in the radio area of each radio base station and capable of receiving transmission signals of the radio base station,
The operation management server acquires the reception status of the transmission signal of each radio base station in the fixed radio terminal, and, for each radio base station, the radio base station to be controlled and another radio base station. The number of fixed wireless terminals simultaneously receiving transmission signals with a predetermined reception power or higher is counted, and when the number is equal to or higher than a threshold, the transmission power from the wireless base station toward another wireless base station is reduced. As described above, a radio base station control method comprising: centrally controlling transmission power and a transmission antenna pattern of the radio base station. A radio communication network is configured with a plurality of radio base stations and mobile radio terminals, and the operation management server determines the transmission power and transmission antenna pattern of each radio base station according to the reception status of the transmission signal of each radio base station in each mobile radio terminal. In a radio base station control method of a radio communication system for controlling
Unlike the mobile radio terminal of the radio communication network, there is a fixed radio terminal that is fixedly present in the radio area of each radio base station and capable of receiving transmission signals of the radio base station,
The operation management server acquires a reception status of a transmission signal of each radio base station in the fixed radio terminal, and transmits a transmission signal of the radio base station to be controlled to a predetermined reception power or more for each radio base station. And the number P of fixed wireless terminals receiving at the same time and the number Q of fixed wireless terminals simultaneously receiving the transmission signals of the wireless base station and other wireless base stations at a predetermined reception power or higher. When the ratio Q / P is equal to or higher than the threshold T1, the transmission power of the radio base station is reduced. When the ratio Q / P of the number is equal to or lower than the threshold T2 (T1> T2), the transmission power of the radio base station is increased. Thus, the radio base station control method characterized by centrally controlling the transmission power of the radio base station.

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