JP2013207562A - Radio communication system, base station, and communication control method - Google Patents

Abstract

An object of the present invention is to improve handover performance and maintain stable communication.
In a wireless communication system including a plurality of base stations 20 capable of communication between base stations and a mobile station 30 wirelessly connectable to any of the base stations, the base station 20 is in communication. When the deterioration of the communication quality in the radio communication with the mobile station 30 is detected, the radio resource scheduling information is acquired from the plurality of base stations 20, and the scheduling information and the radio resource scheduling to the mobile station 30 of the own station are obtained. Based on the other mobile station 30 and the other base station 20 communicating with the other mobile station 30, and the other base station 20 is handed over to the specified other mobile station 30 Request to station 20.
[Selection] Figure 2

Description

  The present invention relates to a wireless communication system, a base station, and a communication control method that perform wireless communication.

  In a wireless communication system including a mobile station and a plurality of base stations, a handover process is performed when the mobile station moves in the cover area of the plurality of base stations (for example, Patent Document 1).

JP 2008-309992 A

  However, the handover process is not started unless the communication quality between the communicating base station and mobile station falls below a predetermined threshold. Therefore, even if the mobile station enters the cell area of another adjacent base station other than the communicating base station, the handover process is not performed unless the communication quality between the communicating base station and the mobile station falls below a predetermined threshold. As a result, there is a risk of causing interference in wireless communication between another base station and a mobile station in communication with the base station.

  In view of such problems, an object of the present invention is to provide a radio communication system, a base station, and a communication control method capable of improving handover performance and maintaining stable communication.

  In order to solve the above problems, a typical configuration according to the present invention includes a plurality of base stations capable of inter-base station communication and a mobile station capable of wireless connection to any one of the base stations. In the wireless communication system, when the base station detects deterioration in communication quality in wireless communication with the mobile station in communication, the base station acquires scheduling information of radio resources from a plurality of base stations, and the scheduling information, Based on the radio resource scheduling of the mobile station to the mobile station, the mobile station identifies another mobile station that is an interference source and another base station that is communicating with the other mobile station, and the specified mobile station A base station controller that requests the other base station to perform handover.

  In addition, the base station further includes a storage unit that stores position information of the base station, and the base station control unit acquires position information of the plurality of base stations, and the acquired positions of the plurality of base stations An adjacent base station that requests the scheduling information may be specified based on the information and the stored location information of the local station.

  Further, the mobile station periodically acquires its own location information and transmits it to the base station, and the base station control unit of the base station transmits the communication quality to the adjacent base station. Requesting information on a mobile station that uses the same radio resource as that of the mobile station at the time when the degradation of the mobile station is detected, and the base station control unit of the adjacent base station receives the request, the same radio resource The base station controller of the base station transmits the same radio resource included in the acquired scheduling information, and transmits the scheduling information including information related to the mobile station using the mobile station and location information of the mobile station. Another mobile station that is the interference source may be specified based on information on the mobile station that uses and the position information of the mobile station.

  Further, the base station control unit of the base station that is communicating with the mobile station may request the other base station to cause the local station to hand over the other mobile station.

Another configuration according to the present invention is a base station of a wireless communication system including a plurality of base stations capable of communication between base stations and a mobile station capable of wireless connection to any one of the base stations. ,
Upon detecting deterioration of communication quality in wireless communication with the mobile station in communication, the wireless resource scheduling information is acquired from a plurality of base stations, and the scheduling information and scheduling of the wireless resource to the mobile station of the own station are acquired. Based on the above, the other mobile station that is the interference source and the other base station that is communicating with the other mobile station are identified, and the other mobile station is handed over to the other mobile station that is identified. A base station control unit that makes a request.

  Another configuration according to the present invention is a communication control method for a wireless communication system including a plurality of base stations capable of inter-base station communication and a mobile station that can be wirelessly connected to any one of the base stations. When the base station detects deterioration in communication quality in wireless communication with the mobile station in communication, the base station acquires scheduling information of radio resources from a plurality of base stations, and the scheduling information and the mobile station Based on scheduling of radio resources to the station, other mobile stations that are interference sources and other base stations that are communicating with the other mobile stations are identified, and the identified other mobile stations are handed over The request is made to the other base station.

  It is possible to improve handover performance and maintain stable communication.

1 is a block diagram illustrating a schematic configuration of a wireless communication system according to an embodiment. It is the block diagram which showed the schematic structure of the base station which concerns on this embodiment. It is the flowchart which showed the radio | wireless communication process of the base station which concerns on this embodiment. It is the flowchart which showed the radio | wireless communication process of the base station which concerns on this embodiment. It is a figure for demonstrating a radio | wireless communication process to the base station which concerns on this embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention. The communication system 10 includes a plurality of base stations 20 (base stations 20a, 20b, 20c), a mobile station 30 (mobile stations 30a, 30b, 30c), and a network 40.

  The base station 20 is wirelessly connected to the mobile station 30. Then, the base station 20 receives data from the network 40 and transmits the data to the mobile station 30. The base station 20 receives data from the mobile station 30 and transmits it to the network 40. Furthermore, the base station 20 transmits / receives data to / from another base station 20 via the network 40 or directly.

  FIG. 2 is a diagram illustrating a configuration of the base station according to the present embodiment. The base station 20 includes a communication unit 210, an interface (I / F) unit 220, a storage unit 230, a control unit 240, and an antenna ANT.

  The communication unit 210 receives the uplink radio signal transmitted from the mobile station 30 via the antenna ANT, converts it into a baseband signal (down-conversion), and then performs demodulation and decoding processing to obtain data. The communication unit 210 outputs the obtained data to the control unit 240.

  The communication unit 210 performs coding and modulation of data from the control unit 240 to obtain a baseband signal, and then converts (upconverts) the baseband signal into a downlink radio signal. The communication unit 210 transmits a downlink radio signal to the mobile station 30 via the antenna ANT.

  The I / F unit 220 receives data addressed to the mobile station 30 from the network 40. The IF unit 220 transmits data received from the mobile station 30 toward the network 40. Further, the I / F unit 220 transmits / receives data to / from another base station 20 via the network 40 or directly.

  The storage unit 230 is configured by a memory, for example, and stores various information used for control in the base station 20 and the like. Moreover, the memory | storage part 230 memorize | stores the cell information regarding the cell of an own station. This cell information is information regarding the installation position of the own station and a predetermined cell radius. The installation position information of the own station may be acquired by a GPS (not shown) provided in the base station 20 or may be input by the operator when the base station 20 is installed. The predetermined cell radius to be stored may be a cell radius that can be formed when each base station transmits a radio signal with the maximum transmission output, or may be a cell radius preset by the operator. Good. The information on the cell radius may be input by the operator when the base station 20 is installed, or may be transmitted via the network 40 when the operation is started after the installation, and may be received by the base station 20.

  The storage unit 230 further stores information on radio resources for a certain period used by the control unit 240 described later for communication with the mobile station 30. The storage unit 230 stores location information of the mobile station 30 that is periodically transmitted from the mobile station 30 in communication.

  The control part 240 is comprised by CPU, for example, and controls the various functions with which the base station 20 is provided. The control unit 240 allocates radio resources when performing radio communication with the mobile station 30. And the control part 240 memorize | stores the information regarding the allocated wireless location source in the memory | storage part 230. FIG. In addition, the control unit 240 periodically acquires the position information of the mobile station 30 from the mobile station 30 in communication and stores it in the storage unit 230. Furthermore, when the communication quality of the radio signal transmitted from the mobile station 30 deteriorates during radio communication with the mobile station 30 using the allocated radio resource, the control unit 240 interferes with radio communication with the mobile station 30. Is determined, and another mobile station 30 that is an interference source of the interference is identified. Then, the control unit 240 requests the other mobile station 30 that is in radio communication with the identified other mobile station 30 to hand over the other mobile station 30. Details of the processing in the control unit 240 will be described later.

  Next, radio communication processing of the base station 20 and the mobile station 30 in the radio communication system 10 will be described with reference to FIGS.

  FIG. 3 is a flowchart showing radio communication processing in the base station 20a in radio communication with the mobile station 30a in the radio communication system 10 shown in FIG. FIG. 4 is a flowchart showing radio communication processing in the base station 20b in radio communication with the mobile station 30b and the base station 20c in radio communication with the mobile station 30c in the radio communication system 10 shown in FIG.

  First, in step S301 in FIG. 3, the control unit 240 of the base station 20a periodically obtains position information of the mobile station 30a from the mobile station 30a in communication.

  In step S302, the control unit 240 of the base station 20a determines whether the reception quality value (for example, RSSI) of the radio signal transmitted by the mobile station 30a has deteriorated.

  When the control unit 240 of the base station 20a determines that the reception quality value has deteriorated and interference has occurred (corresponding to step S302 Yes), in step S303, the control unit 240 acquires the position information of the plurality of base stations 20, and step S304. Migrate to This location information may be obtained in advance by acquiring location information of a plurality of base stations 20 stored in the storage unit 230 of the base station 20a in advance, or through the I / F unit 220 of the base station 20a each time. The position information may be acquired from each of the plurality of base stations 20, or the position information may be acquired from a higher-level device (for example, a server).

  On the other hand, when the control unit 240 of the base station 20a determines that the reception quality value has not deteriorated and interference has not occurred (corresponding to step S302 Yes), the control unit 240 proceeds to step S301 and continues the above processing.

  In step S304, the control unit 240 of the base station 20a uses the acquired position information of the plurality of base stations 20 and the position information of the own station to make adjacent base stations 20 (here, the base station shown in FIG. 1). 20b and 20c). In specifying the adjacent base station 20, for example, the control unit 240 of the base station 20a calculates the distance between the own station and each of the plurality of base stations 20 that acquired the position information, and the calculated distance is Then, a base station 20 that is about twice the predetermined cell radius stored in the storage unit 230 is specified.

  In step S305, the control unit 240 of the base station 20a requests the specified adjacent base stations 20b and 20c for scheduling information of radio resources of each base station 20 via the I / F unit 220.

  In step S401 of FIG. 4A, the control unit 240 of the base stations 20b and 20c receives the radio resource scheduling information and the scheduling information request from the base station 20a via the I / F unit 220.

  In step S402, the control unit 240 of the base stations 20b and 20c transmits radio resource scheduling information to the base station 20a via the I / F unit 220.

  In step S306 of FIG. 3, the control unit 240 of the base station 20a receives the scheduling information of the radio resources of each base station 20 from the adjacent base stations 20b and 20c.

  In step S307, the control unit 240 of the base station 20a specifies the mobile station 30 that is an interference source and the base station 20 that is in radio communication with the mobile station 30 from the scheduling information received from the adjacent base stations 20b and 20c. .

  Here, with reference to FIG. 5, details regarding the processing of steps S305 to S307 in FIG. 3 and steps S401 to S402 in FIG. 4 will be described. FIG. 5 illustrates scheduling of the base stations 20a to 20c in a frame including radio resources when the control unit 240 of the base station 20a determines that interference has occurred in step S302. Here, it is assumed that the radio resource is defined by time and frequency. 5A shows scheduling of the base station 20a, FIG. 5B shows scheduling of the base station 20b, and FIG. 5C shows scheduling of the base station 20c.

  And the control part 240 of the base station 20a can request | require what contains the information as mentioned later as scheduling information.

(About the first scheduling information)
In step S305, the control unit 240 of the base station 20a determines all the radio resources in the frame having the same timing as the frame including the radio resource X determined to be causing interference, and the mobile station 30 to which the radio resource is assigned. Then, information that associates with the location information of the mobile station 30 is requested as scheduling information (hereinafter referred to as first scheduling information).

  In step S401, the control unit 240 of the base station 20b requested for the first scheduling information, as shown in FIG. 5B, each radio resource, the mobile station 30 to which each radio resource is assigned, In step S402, first scheduling information including information associated with the location information of the mobile station 30 (for example, information associated with the location information of the radio resource Y, the mobile station 30b, and the mobile station 30b) The data is transmitted to the base station 20a via the / F unit 220. The control unit 240 of the base station 20c also performs the same processing as the control unit 240 of the base station 20b in steps S401 to S402.

  In step S306, the control unit 240 of the base station 20a receives the first scheduling information from the base stations 20b and 20c. Subsequently, in step S307, the control unit 240 of the base station 20a is defined by the same time and frequency as the radio resource X determined as causing interference from the first scheduling information received from the base station 20b. The mobile station 30b to which the radio resource Y is allocated and the position information of the mobile station 30b are extracted. In addition, the control unit 240 of the base station 20a allocates a radio resource Z defined by the same time and frequency as the radio resource X determined to be causing interference from the first scheduling information received from the base station 20c. Mobile station 30c and the position information of the mobile station 30c are extracted.

  Next, the control unit 240 of the base station 20a compares the position information of the mobile station 30a with the position information of the mobile stations 30b and 30c, and determines whether the distance from the mobile station 30a is within a threshold. As a result of the determination, the mobile station 30 that has determined that the distance from the mobile station 30a is within the threshold is specified as the mobile station 30 that is the interference source (here, the mobile station 30c). On the other hand, it is assumed that the mobile station 30 (in this case, the mobile station 30b) determined that the distance from the mobile station 30a exceeds the threshold is not the interference source mobile station 30. Then, the control unit 240 of the base station 20a identifies the mobile station 30c that is an interference source and the base station 20c that is in radio communication with the mobile station 30c.

(About the second scheduling information)
In step S305, the control unit 240 of the base station 20a assigns the radio resource corresponding to the radio resource X in the frame having the same timing as the frame including the radio resource X determined to have interference. And information associating the location information of the mobile station 30 is requested as scheduling information (hereinafter referred to as second scheduling information).

  In step S401, the control unit 240 of the base station 20b requested for the second scheduling information, as shown in FIG. 5B, each radio resource, the mobile station 30 to which each radio resource is assigned, In step S402, the second scheduling information including information associated with the location information of the mobile station 30 (here, information associated with only the location information of the mobile station 30b and the mobile station 30b) The data is transmitted to the base station 20a via the F unit 220. The control unit 240 of the base station 20c also performs the same processing as the control unit 240 of the base station 20b in steps S401 to S402. When there is no mobile station 30 to which radio resources corresponding to the radio location source X are allocated, the second scheduling information may be transmitted including information indicating that, or the second scheduling information. You do not have to send it.

  In step S306, the control unit 240 of the base station 20a receives the second scheduling information from the base stations 20b and 20c. Subsequently, in step S307, the control unit 240 of the base station 20a extracts the mobile station 30b and the position information of the mobile station 30b from the second scheduling information received from the base station 20b. Further, the control unit 240 of the base station 20a extracts the mobile station 30c and the position information of the mobile station 30c from the second scheduling information received from the base station 20c.

  Next, the control unit 240 of the base station 20a compares the position information of the mobile station 30a with the position information of the mobile stations 30b and 30c, and determines whether the distance from the mobile station 30a is within a threshold. As a result of the determination, the mobile station 30 that has determined that the distance from the mobile station 30a is within the threshold is specified as the mobile station 30 that is the interference source (here, the mobile station 30c). On the other hand, it is assumed that the mobile station 30 (in this case, the mobile station 30b) determined that the distance from the mobile station 30a exceeds the threshold is not the interference source mobile station 30. Then, the control unit 240 of the base station 20a identifies the mobile station 30c that is an interference source and the base station 20c that is in radio communication with the mobile station 30c.

  In step S308 of FIG. 3, the control unit 240 of the base station 20a requests the base station 20c that is in radio communication with the mobile station 30c that is an interference source to perform handover of the mobile station 30c.

  In step S451 in FIG. 4B, the control unit 240 of the base station 20c receives a handover request for the mobile station 30c from the base station 20a.

  In step S452, the control unit 240 of the base station 20c starts processing for handing over the mobile station 30c to the base station 20a.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention.

  For example, functions included in each member, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. Is possible.

10 communication system, 20 base station, 30 mobile station, 40 network, 210 communication unit, 220 I / F unit, 230 storage unit, 240 control unit, ANT antenna.

Claims (6)

A wireless communication system comprising a plurality of base stations capable of communication between base stations, and a mobile station wirelessly connectable to any one of the base stations,
The base station
Upon detecting deterioration of communication quality in wireless communication with the mobile station in communication, the wireless resource scheduling information is acquired from a plurality of base stations, and the scheduling information and scheduling of the wireless resource to the mobile station of the own station are acquired. Based on the above, the other mobile station that is the interference source and the other base station that is communicating with the other mobile station are identified, and the other mobile station is handed over to the other mobile station that is identified. A wireless communication system comprising: a base station control unit that makes a request. The base station further includes a storage unit that stores position information of the own station,
The base station control unit acquires position information of the plurality of base stations, and requests the scheduling information based on the acquired position information of the plurality of base stations and the stored position information of the own station. Identify the base station to
The wireless communication system according to claim 1. The mobile station periodically acquires its own location information and transmits it to the base station,
The base station control unit of the base station requests information on the mobile station using the same radio resource as the mobile station at the time of detecting the communication quality degradation to the adjacent base station,
Upon receiving the request, the base station controller of the adjacent base station transmits the scheduling information including information on the mobile station using the same radio resource and the location information of the mobile station,
The base station control unit of the base station may be the interference source based on the information related to the mobile station using the same radio resource and the location information of the mobile station included in the acquired scheduling information. Identify mobile stations
The wireless communication system according to claim 2. The base station controller of the base station that is communicating with the mobile station requests the other base station to hand over the other mobile station to the local station.
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. A base station of a wireless communication system comprising a plurality of base stations capable of communication between base stations and a mobile station capable of wireless connection to any of the base stations,
Upon detecting deterioration of communication quality in wireless communication with the mobile station in communication, the wireless resource scheduling information is acquired from a plurality of base stations, and the scheduling information and scheduling of the wireless resource to the mobile station of the own station are acquired. Based on the above, the other mobile station that is the interference source and the other base station that is communicating with the other mobile station are identified, and the other mobile station is handed over to the other mobile station that is identified. A base station control unit that requests the base station. A communication control method for a wireless communication system comprising a plurality of base stations capable of communication between base stations and a mobile station wirelessly connectable to any of the base stations,
The base station
Upon detecting deterioration of communication quality in wireless communication with the mobile station in communication, the wireless resource scheduling information is acquired from a plurality of base stations, and the scheduling information and scheduling of the wireless resource to the mobile station of the own station are acquired. Based on the above, the other mobile station that is the interference source and the other base station that is communicating with the other mobile station are identified, and the other mobile station is handed over to the other mobile station that is identified. Request,
A communication control method characterized by the above.

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