JP2014192618A - Communication system and communication control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve throughput of an entire communication system in the communication system in which a high-speed line and a low-speed line are used together for connection between a base station and a network.SOLUTION: A communication system according to the invention is a communication system including a plurality of base stations 100, a communication terminal 400, and a radio relay device 200 for relaying data transmitted and received between the base stations 100 and the communication terminal 400. Each base station 100 transmits line information on a communication line connecting the base station 100 and a network 300. The radio relay device 200 receives line information from at least one base station 100 and selects a base station 100 with which the relay device should connect on the basis of the line information.

Description

  The present invention relates to a communication system and a communication control method, and more particularly to a communication system including a radio relay device and a communication control method.

  In order for a communication terminal to communicate with a base station, the communication terminal needs to be located in a range where radio waves from the base station can reach. However, there are areas where it is difficult for radio waves to reach because there are many obstacles in urban areas where mountainous areas and high-rise buildings are lined up.

  By adding more base stations, it is possible to cover such areas where radio waves do not reach. However, from the viewpoint of cost reduction and the like, the installation of a wireless relay device often covers an area where such radio waves do not reach.

  The radio relay apparatus receives radio signals from a plurality of neighboring base stations, and selects a base station to be connected based on the received power intensity, received signal quality, and the like of radio signals received from each base station (for example, Patent Document 1). reference). The received power strength indicator is, for example, RSSI (Received Signal Strength Indicator), and the received signal quality indicator is, for example, SINR (Signal to Interference and Noise Ratio).

JP 2003-101465 A

  However, even when the wireless relay device selects a base station to be connected based on the received power intensity or the received signal quality of the wireless signal received from the base station as described above, the optimum throughput is achieved for the entire communication system. There were cases where it was not possible.

  For example, although the base station is connected to the network by a communication line such as an optical fiber, the base station connected to the network by a low-capacity low-speed line may be selected as the connection destination by the radio relay apparatus. In this case, even if the communication environment between the wireless relay device and the base station is good due to insufficient capacity of the communication line, the communication terminal connected to the wireless relay device cannot perform wireless communication. In some cases, the overall throughput of the system could not be achieved.

  Accordingly, an object of the present invention made in view of such points is to improve the throughput of the entire communication system in a communication system in which a high-speed line and a low-speed line are mixedly used for connection between a base station and a network. It is an object of the present invention to provide a communication system and a communication control method that can be used.

  In order to solve the above problems, a communication system according to the present invention is a communication system including a plurality of base stations, a communication terminal, and a wireless relay device that relays data transmitted and received between the base station and the communication terminal. Each base station transmits line information about a communication line connecting the base station and the network, and the wireless relay device receives the line information from at least one of the base stations, Based on the line information, the base station to be connected is selected.

  In the communication system according to the present invention, each base station transmits a flag indicating whether or not a communication line connecting the base station and the network is a high-speed line as the line information, It is preferable that the radio relay apparatus preferentially selects a base station determined to be connected to the network through a high-speed line based on the flag as a connection destination.

  Further, in the communication system according to the present invention, when there are a plurality of the base stations that are determined to be connected to the network through a high-speed line, the wireless relay device receives received power intensity among the plurality of base stations. It is preferable to preferentially select the base station having the maximum as the connection destination.

  Further, in the communication system according to the present invention, when there is no base station that determines that the wireless relay device is connected to the network through a high-speed line, the base station with the highest received power strength is given priority. It is preferable to select the connection destination.

  In the communication system according to the present invention, it is preferable that the base station transmits the line information using a vacant bit of a broadcast channel.

  In order to solve the above problems, a communication control method according to the present invention includes a plurality of base stations, a communication terminal, and a radio relay apparatus that relays data transmitted and received between the base station and the communication terminal. A communication control method in a communication system, wherein each base station transmits line information about a communication line connecting the base station and a network, and the radio relay apparatus includes at least one base Receiving the line information from a station, and the wireless relay device selecting a base station to be connected based on the line information.

  ADVANTAGE OF THE INVENTION According to this invention, the throughput of the whole communication system can be improved in the communication system in which the high-speed line and the low speed line are mixed and used for the connection between a base station and a network.

1 is a schematic diagram of a communication system according to an embodiment of the present invention. It is a schematic block diagram of the base station which concerns on one Embodiment of this invention. It is a schematic block diagram of the radio relay apparatus concerning one embodiment of the present invention. It is a flowchart which shows operation | movement of the base station which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the radio relay apparatus which concerns on one Embodiment of this invention.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present invention. The communication system 10 includes a plurality of base stations 100 (100a and 100b), a radio relay device 200, a network 300, and a communication terminal 400. Hereinafter, when the contents common to the base station 100a and the base station 100b are described, they are simply referred to as the base station 100.

  1 shows a case where there are two base stations 100, one wireless relay device 200, and one communication terminal 400, this is an example, and there are three or more base stations 100, Two or more wireless relay devices 200 and two or more communication terminals 400 may be provided.

  Base station 100 is connected to network 300 via a communication line such as an optical fiber. Base station 100 a is connected to network 300 via communication line 20, and base station 100 b is connected to network 300 via communication line 30. Communication lines include high speed lines and low speed lines. Since the high-speed line has a large capacity, even if the base station 100 connected to the network 300 through the high-speed line is connected to the radio relay apparatus 200, there is little possibility that the capacity is insufficient. However, since the low-speed line has a small capacity, when the base station 100 connected to the network 300 via the low-speed line connects to the wireless relay device 200, the communication terminal 400 connected to the wireless relay device 200 is not connected due to a shortage of capacity. Wireless communication may not be possible.

  The wireless relay device 200 relays data transmitted and received by wireless communication between the base station 100 selected as the connection destination and the communication terminal 400.

  FIG. 2 is a schematic block diagram of a base station according to an embodiment of the present invention. The base station 100 includes a communication unit 110, a control unit 120, and a storage unit 130.

  The communication unit 110 transmits / receives data to / from the wireless relay device 200 or the communication terminal 400 by wireless communication directly via an antenna.

  In uplink, communication unit 110 down-converts a radio signal received from radio relay apparatus 200 or communication terminal 400 to convert it into a baseband signal, performs processing such as AD conversion, and then transmits the data to control unit 120. provide. Further, in the downlink, the communication unit 110 performs processing such as DA conversion on the transmission data received from the control unit 120, up-converts the baseband signal after DA conversion, and generates a wireless signal for transmission. It transmits to the radio relay apparatus 200 or the communication terminal 400.

  The control unit 120 controls and manages the entire base station 100 including each functional block of the base station 100. The control unit 120 is configured as software executed on an arbitrary suitable processor such as a CPU (central processing unit) or a dedicated processor (for example, DSP (digital signal processor)) specialized for each process. You can also.

  The control unit 120 transmits the data received from the communication unit 110 to the network 300 via the communication line. In addition, the control unit 120 provides data received from the network 300 via a communication line to the communication unit 110.

  The control unit 120 causes the communication unit 110 to transmit the line information about the communication line connecting the base station 100 and the network 300 in the downlink control signal. For example, the control unit 120 determines whether the communication line connecting the base station 100 and the network 300 is a high-speed line or a low-speed line by providing an identification bit in an empty bit of the broadcast channel, This is notified by setting a flag indicating that the

  For example, when the communication line 20 connecting the base station 100a and the network 300 is a high-speed line, the control unit 120 sets a flag indicating that the communication line 20 is a high-speed line. For example, when the communication line 30 connecting the base station 100b and the network 300 is a low speed line, the control unit 120 does not set a flag indicating that the communication line 20 is a high speed line.

  The storage unit 130 stores line information on what communication line is connected between the base station 100 and the network 300.

  FIG. 3 is a schematic block diagram of a wireless relay device according to an embodiment of the present invention. The radio relay apparatus 200 includes a terminal side communication unit 210, a base station side communication unit 220, a control unit 230, and a storage unit 240.

  In the uplink, the terminal-side communication unit 210 down-converts the radio signal received from the communication terminal 400 to convert it into a baseband signal, and provides the baseband signal to the base station-side communication unit 220.

  In the downlink, the terminal-side communication unit 210 up-converts the baseband signal received from the base station-side communication unit 220, converts the baseband signal into a radio signal, and transmits the radio signal to the communication terminal 400.

  In the uplink, the base station side communication unit 220 up-converts the baseband signal received from the terminal side communication unit 210 to convert it into a radio signal, and transmits the radio signal to the base station 100.

  In the downlink, the base station side communication unit 220 down-converts the radio signal received from the base station 100 and converts it into a baseband signal, and provides the baseband signal to the terminal side communication unit 210.

  The control unit 230 controls and manages the entire wireless relay device 200 including each functional block of the wireless relay device 200. The control unit 230 can be configured as software executed on any suitable processor such as a CPU, or can be configured by a dedicated processor (for example, a DSP (digital signal processor)) specialized for each process. .

  The control unit 230 controls the radio relay apparatus 200 so as to perform cell search when the power is turned on, and detects surrounding base stations 100.

  The control unit 230 detects the received power intensity of the radio signal received from each neighboring base station 100 detected by the cell search. The indicator of the received power intensity is, for example, RSSI.

  In addition, the control unit 230 receives line information regarding a communication line connecting the peripheral base station 100 and the network 300 from each peripheral base station 100 detected by the cell search. For example, if the flag indicating that the high-speed line is set in the identification bit provided in the broadcast channel received from the base station 100, the control unit 230 connects the base station 100 to the network 300 via the high-speed line. It is determined that

  Based on the line information received from base station 100, control unit 230 preferentially selects base station 100 determined to be connected to network 300 via a high-speed line as a connection destination base station. When there are a plurality of base stations 100 determined to be connected to the network 300 via a high-speed line, or when there is no base station 100 determined to be connected to the network 300 via a high-speed line, the control unit 230 receives A base station with high power intensity is preferentially selected as a connection destination base station.

  The storage unit 240 stores various information.

  The operation of the base station 100 according to the embodiment of the present invention will be described with reference to the flowchart shown in FIG.

  The control unit 120 determines whether or not the base station 100 is connected to the network 300 through a high-speed line at the start of communication such as when the power is turned on (step S101).

  If it is determined in step S101 that the base station 100 is connected to the network 300 via a high speed line, the control unit 120 sets a flag indicating that the base station 100 is connected to the network 300 via a high speed line (step S102).

  If it is determined in step S101 that the base station 100 is not connected to the network 300 via a high speed line, the control unit 120 does not set a flag indicating that the base station 100 is connected to the network 300 via a high speed line (step S103).

  Based on the result of step S102 or step S103, control unit 120 causes the communication unit 110 to transmit a broadcast channel without setting a flag or without setting a flag (step S104).

  The operation of the wireless relay device 200 according to an embodiment of the present invention will be described with reference to the flowchart shown in FIG.

  The control unit 230 performs cell search at the start of communication such as when the power is turned on, and detects neighboring base stations 100 (step S201).

  The controller 230 detects the received power intensity of the radio signal received from each neighboring base station 100 (step S202).

  The control unit 230 detects a flag included in the broadcast channel received from each neighboring base station 100 (step S203). Note that the order of steps S202 and S203 may be reversed or simultaneous.

  The control unit 230 determines whether or not there is a base station 100 on which a flag indicating that the received broadcast channel is a high-speed line is set (step S204).

  If it is determined in step S204 that there is a base station 100 on which a flag indicating a high-speed line is set, the control unit 230 determines the received power intensity among the base stations connected to the network 300 via the high-speed line. Is selected as the connection destination (step S205).

  If it is determined in step S204 that there is no base station 100 on which a flag indicating a high-speed line is set, the control unit 230 selects the base station 100 having the maximum received power intensity as a connection destination (step S206). .

  Thus, according to the present embodiment, the radio relay apparatus 200 acquires line information about a communication line connecting the base station 100 and the network 300, and the base connected to the network 300 through a high-speed line. By preferentially selecting the station 100 as the connection destination, it is possible to suppress the communication terminal 400 from being unable to perform wireless communication due to insufficient capacity of the communication line connecting the base station 100 and the network 300, and to reduce the throughput of the entire communication system. Can be improved.

  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.

  Further, in the present embodiment, the case where the wireless communication between the base station 100 and the communication terminal 400 is relayed by one wireless relay device 200 has been described as an example, but the relay is performed by a plurality of wireless relay devices 200. The present invention can be applied even if the configuration is such.

DESCRIPTION OF SYMBOLS 10 Communication system 100 Base station 110 Communication part 120 Control part 130 Storage part 200 Radio relay apparatus 210 Terminal side communication part 220 Base station side communication part 230 Control part 240 Storage part 300 Network 400 Communication terminal

Claims (6)

A communication system including a plurality of base stations, a communication terminal, and a wireless relay device that relays data transmitted and received between the base station and the communication terminal,
Each base station transmits line information about a communication line connecting the base station and the network,
The wireless relay device receives the channel information from at least one of the base stations, and selects a base station to be connected based on the channel information. The communication system according to claim 1,
Each of the base stations transmits, as the line information, a flag indicating whether or not a communication line connecting the base station and the network is a high-speed line,
The wireless relay device preferentially selects a base station determined to be connected to the network through a high-speed line by the flag as a connection destination. The communication system according to claim 2,
When there are a plurality of base stations that are determined to be connected to the network through a high-speed line, the wireless relay device gives priority to a base station having the maximum received power intensity among the plurality of base stations. A communication system characterized by being selected as a connection destination. The communication system according to claim 2,
The wireless relay device, when there is no base station determined to be connected to the network through a high-speed line, preferentially selects a base station with the highest received power intensity as a connection destination. Communications system.   The communication system according to any one of claims 1 to 4, wherein the base station transmits the line information using a vacant bit of a broadcast channel. A communication control method in a communication system including a plurality of base stations, a communication terminal, and a wireless relay device that relays data transmitted and received between the base station and the communication terminal,
Each base station transmitting line information about a communication line connecting the base station and a network; and
The wireless relay device receiving the line information from at least one of the base stations;
The wireless relay device selecting a base station to be connected based on the line information.

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