Base station selecting method, mobile station and base station

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention selects a base station that selects the optimum base station to which the mobile station connects from among a plurality of base stations that wirelessly connect to the mobile station when the mobile station relays and connects to the communication network in the wireless network. Regarding methods, mobile stations and base stations.

【0002】

[Conventional technology]

Generally, in a wireless network such as a cellular system or a wireless LAN system using a base station, a plurality of base stations relayed to the communication network and a mobile station connected to these base stations via a wireless line are used. When a mobile station communicates with a communication network, it is necessary to select the most suitable base station to which the mobile station connects from among a plurality of base stations.

【0003】

FIG. 11 is a system configuration diagram showing an overall configuration of a wireless network that employs a conventional base station selection method.

【0004】

The wireless network 100 shown in FIG. 11 is connected to the relay server 102 connected to the communication network 101, the four base stations 103 relay-connected to the relay server 102, and these base stations 103 via a wireless line. It has a mobile station 104.

【0005】

Further, in the connection configuration between these four base stations 103 and the relay server 102, the relay server 102 connects to the first base station 103A, the first base station 103A connects to the second base station 103B, and the second base station The configuration is such that 103B is connected to the third base station 103C, and the third base station 103C is connected to the fourth base station 103D.

【0006】

For example, when the mobile station 104 communicates with the relay server 102, the mobile station 104 receives a base station selection signal from the first base station 103A, the second base station 103B, the third base station 103C, and the fourth base station 103D. Are received respectively, and the received electric field strength and the like of these base station selection signals are measured.

【0007】

The mobile station 104 measures the reception status such as the reception electric field strength of each base station selection signal, and based on the measurement result, among the base stations 103 that can be communicated and connected, the base station 103 with the optimum reception status is selected. By selecting and wirelessly connecting to this base station 103, a communication connection is made with the relay server 102.

【0008】

As described above, according to the conventional base station selection method, the mobile station 104 measures the reception status such as the reception electric field strength of each base station selection signal, and selects the base station 103 with the optimum reception status based on the measurement result. can do.

【0009】

Further, as a conventional base station selection method, each base station 103 receives a transmission signal from the mobile station 104, measures the reception status, and each of these base stations 103 transmits the measurement result to a control station or the like. Therefore, the control station may be able to select the base station 103 having the optimum reception condition based on these measurement results.

【0010】

That is, according to such a conventional base station selection method, the communication quality between the mobile station 104 and the base station 103 is collected, and the base station 103 having the highest communication quality, for example, the highest received electric field strength is selected. , The mobile station 104 can be selected as the optimum base station to be wirelessly connected.

【0011】

[Problems to be Solved by the Invention]

However, according to the above-mentioned conventional base station selection method, the base station 103 having the best communication quality between the mobile station 104 and the base station 103 is selected as the optimum base station to which the mobile station 104 wirelessly connects. However, for example, when the mobile station 104 relay-connects to the relay server 102, the communication quality with the first base station 103A is good, but the communication quality with the fourth base station 103D is the best. The 4th base station 103D is selected as the optimum base station, and the mobile station 104 is wirelessly connected to the 4th base station 103D, but the traffic from the mobile station 104 to the relay server 102 is the 4th base station 103D, Since it is transmitted to the relay server 102 via the third base station 103C, the second base station 103B, and the first base station 103A, it is compared with the case where the mobile station 104 is wirelessly connected to the first base station 103A, for example. Then, the amount of traffic between these base stations 103 increases, and the transmission delay between the mobile station 104 and the relay server 102 also increases.

【0012】

Further, according to the above-mentioned conventional base station selection method, a case where the route between the base stations 103 is connected by a wired line has been described. For example, a wireless multi-hop network in which the route between the base stations 103 is connected by a wireless line is used. In this case, since the communication quality on the route between the base stations 103, for example, the propagation loss and the signal power to noise ratio, are different, not only the communication quality between the mobile station 104 and the base station 103D but also between the mobile station 104 and the relay server 102. The communication quality of the wireless link existing in the relay path of is greatly affected by the performance.

【0013】

For example, even if the communication quality between the mobile station 104 and the third base station 103C is the best and the third base station 103C is selected as the optimum base station, the route from the third base station 103C to the relay server 102 can be used. May contain many wireless links, and even if the third base station 103C is selected as the optimum base station, the communication quality between the mobile station 104 and the relay server 102 is not necessarily optimal. Is not always.

【0014】

The present invention has been made in view of the above points, and an object of the present invention is to allow a mobile station to obtain optimum communication quality with a communication destination by efficiently using the resources of the entire wireless network. The purpose is to provide a possible base station selection method, mobile station and base station.

【0015】

[Means for solving problems]

In order to achieve the above object, the base station selection method of the present invention has a plurality of base stations relay-connected to a communication network and a mobile station connected to these base stations via a wireless line, and the movement This is a base station selection method for selecting the optimum base station to be connected to the mobile station from among the plurality of base stations when the station relay-connects to the communication network, and is held by each base station. , A transmission step of transmitting the base station route cost, which is the cost of the route connecting the own station and the communication network, to the mobile station, and a reception step of receiving the base station route cost from each base station by the mobile station. The mobile station measures the route cost for the base station between the own station and the base station for each base station, and the mobile station bases the route cost for the base station and the route cost for the base station. A comprehensive route calculation step for calculating the total route cost for each base station by adding for each station, a comprehensive route storage step for the mobile station to store the total route cost for each base station, and the mobile station communicating with the user. When making a relay connection with the network, it has a base station selection step of selecting a base station related to the optimum total route cost based on the total route cost stored.

【0016】

Therefore, according to the base station selection method of the present invention, each base station holds the route cost for the base station between the own station and the communication network, and the mobile station is for the base station between the own station and each base station. The route cost is measured, and the mobile station adds the route cost for the base station and the route cost for the base station for each base station to calculate the total route cost for each base station, and stores the total route cost for each base station. At the same time, when a mobile station relays to a communication network, the base station related to the optimum total route cost is selected based on the total route cost stored in the memory, so that the resources of the entire wireless network can be efficiently used. The mobile station can obtain the optimum communication quality with the communication network.

【0017】

Further, in the base station selection method of the present invention, the plurality of base stations are connected via a wireless line.

【0018】

Therefore, according to the base station selection method of the present invention, even if the base stations are connected to each other via a wireless line in a wireless multi-hop network system, the mobile station can obtain the optimum communication quality with the communication network. it can.

【0019】

Further, in the base station selection method of the present invention, the transmission step uses the base station selection signal to transmit the route cost for the base station to the mobile station.

【0020】

Therefore, according to the base station selection method of the present invention, the base station route cost is transmitted to the mobile station by using the normally used base station selection signal. Therefore, the base station route cost is transmitted. There is no need to secure a new channel.

【0021】

Further, in the base station selection method of the present invention, the route cost for the base station, the route cost for the base station, and the total route cost are the number of relays, the propagation loss, the signal power to the noise ratio, or the signal to the interference power ratio. The route information is based on either one.

【0022】

Therefore, according to the base station selection method of the present invention, the base station route cost, the base station route cost, and the total route cost can be set to any of the number of relays, propagation loss, signal power to noise ratio, or signal to interference power ratio. Since the route information is based on the above, it is possible to perform a variety of comparisons in selecting the optimum base station.

【0023】

Further, in the base station selection method of the present invention, the mobile station measures a route cost between its own station and the base station, which is different from the route cost for the base station, as a preliminary determination route cost for each base station. The mobile station has a preliminary determination measurement step and a preliminary determination storage step for storing the preliminary determination route cost for each base station, and the base station selection step has a plurality of the optimum total route costs. In this case, the base station related to the optimum preliminary judgment route cost is selected based on the preliminary judgment route cost related to the base station having the optimum total route cost.

【0024】

Therefore, according to the base station selection method of the present invention, the mobile station measures a route cost of a type different from the route cost for the base station between the own station and the base station as a preliminary determination route cost for each base station. If there are a plurality of optimal total route costs, select the base station related to the optimum preliminary determination route cost based on the preliminary determination route cost related to the base station of these optimum total route costs. Therefore, it is possible to improve the selection accuracy of selecting the optimum base station.

【0025】

Further, in the base station selection method of the present invention, the path cost for preliminary determination is set to be path information based on any one of the number of relays, propagation loss, signal power to noise ratio, and signal to interference power ratio.

【0026】

Therefore, according to the base station selection method of the present invention, the path cost for preliminary determination is set as the path information based on any one of the number of relays, propagation loss, signal power to noise ratio, and signal to interference power ratio, and is therefore optimal. A wide variety of comparisons can be made when selecting a variety of base stations.

【0027】

Further, in order to achieve the above object, the mobile station of the present invention connects to a plurality of base stations relay-connected to the communication network via a wireless line, and when relay-connecting to the communication network, the plurality of base stations. It is a mobile station that selects the most suitable base station among the stations, and among the plurality of base stations, the base station that can be connected to the communication and the route cost for the base station between the communication networks are calculated as the base station that can be connected to the communication. Base station route cost to be received for each base station route cost measurement to measure the route cost for the base station between the own station and the base station to which the communication can be connected for each base station to which the communication can be connected. The total route cost for calculating the total route cost for each base station to which communication can be connected by adding the route cost for the base station and the route cost for the base station for each of the means and the base station to which communication can be connected. The calculation means, the total route cost storage means for storing the total route cost for each base station to which communication can be connected, and the total route stored in the total route cost storage means when the own station relay-connects to the communication network. It has a base station selection means for selecting a base station related to the optimum total route cost based on the cost.

【0028】

Therefore, according to the mobile station of the present invention, the route cost for the base station that can be connected to the communication and the route cost for the base station between the communication networks is received for each base station that can be connected to the communication, and the base station is for the base station and the base station. Measure the route cost, add the route cost for the base station and the route cost for the base station for each base station to calculate the total route cost for each base station, store the total route cost for each base station, and move. When a station relays to the communication network, the base station related to the optimum total route cost is selected based on the total route cost in storage, so the resources of the entire wireless network can be used efficiently. As a result, the mobile station can obtain the optimum communication quality with the communication network.

【0029】

Further, in the mobile station of the present invention, the plurality of base stations are connected via a wireless line.

【0030】

Therefore, according to the mobile station of the present invention, even if the base stations are connected to each other via a wireless line in a wireless multi-hop network system, the mobile station can obtain the optimum communication quality with the communication network.

【0031】

Further, in the mobile station of the present invention, the route cost for the base station, the route cost for the base station, and the total route cost are any of the number of relays, the propagation loss, the signal power to noise ratio, or the signal to interference power ratio. The route information is based on one.

【0032】

Therefore, according to the mobile station of the present invention, the route cost for the base station, the route cost for the base station, and the total route cost are set to any one of the number of relays, the propagation loss, the signal power to the noise ratio, or the signal to the interference power ratio. Since the route information is based on the above, it is possible to perform a variety of comparisons in selecting the optimum base station.

【0033】

Further, the mobile station of the present invention uses a route cost of a type different from the route cost for the base station between the own station and the base station to which the communication can be connected as a preliminary determination route cost, and the base that can be connected to the communication. The base station selection means includes a preliminary determination route cost measuring means for measuring each station and a preliminary determination route cost storing means for storing the preliminary determination route cost for each base station to which communication can be connected. When there are a plurality of the optimum total route costs, the base station related to the optimum preliminary determination route cost is selected based on the preliminary determination route cost related to the base station of the optimum total route cost.

【0034】

Therefore, according to the mobile station of the present invention, a route cost of a type different from the route cost for the base station between the own station and the base station is measured for each base station as a preliminary determination route cost, which is optimal. When there are multiple total route costs, the base station related to the optimum preliminary judgment route cost is selected based on the preliminary judgment route cost related to the base station with the optimum total route cost. It is possible to improve the selection accuracy of selecting a suitable base station.

【0035】

Further, in the mobile station of the present invention, the path cost for preliminary determination is set to be path information based on any one of the number of relays, propagation loss, signal power to noise ratio, and signal to interference power ratio.

【0036】

Therefore, according to the mobile station of the present invention, the path cost for preliminary determination is set as the route information based on any one of the number of relays, the propagation loss, the signal power to the noise ratio, or the signal to the interference power ratio. A wide variety of comparisons can be made when selecting stations.

【0037】

Further, the base station of the present invention is a base station that relay-connects to a communication network, connects to a mobile station via a wireless line, and transmits a base station selection signal to the mobile station, and is a self-station and a communication network. A base station route cost storage means for storing the base station route cost between them, and a base for transmitting the base station route cost stored in the base station route cost storage means to the mobile station by the base station selection signal. It has a route cost transmission means for stations.

【0038】

Therefore, according to the base station of the present invention, the route cost for the base station between the own station and the communication network is stored, and the route cost for the base station in this storage is transmitted to the mobile station by the base station selection signal. Therefore, the mobile station can obtain the optimum communication quality with the communication network by efficiently using the resources of the entire wireless network.

【0039】

Further, in the base station of the present invention, the base stations are connected to each other by communication via a wireless line.

【0040】

Therefore, according to the base station of the present invention, even if the base stations are connected to each other via a wireless line in a wireless multi-hop network system, the mobile station can obtain the optimum communication quality with the communication network.

【0041】

Further, in the base station of the present invention, the route cost for the base station is set to be route information based on any one of the number of relays, propagation loss, signal power to noise ratio, and signal to interference power ratio.

【0042】

Therefore, according to the base station of the present invention, the route cost for the base station is set as the route information based on any one of the number of relays, the propagation loss, the signal power to the noise ratio, and the signal to the interference power ratio. A wide variety of comparisons can be made when selecting stations.

【0043】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the wireless network shown in the first embodiment in which the base station selection method of the present invention is adopted will be described with reference to the drawings. FIG. 1 is a system configuration diagram showing the overall configuration of the wireless network shown in the first embodiment.

【0044】

The wireless network 10 shown in FIG. 1 is connected to a relay server 12 connected to the communication network 11, four base stations 20 relay-connected to the relay server 12, and these base stations 20 via a wireless line. It has a mobile station 30 and.

【0045】

Further, in the connection configuration between these four base stations 20 and the relay server 12, the relay server 12 connects to the first base station 20A, the first base station 20A connects to the second base station 20B, and the second base station The configuration is such that 20B is connected to the third base station 20C, and the third base station 20C is connected to the fourth base station 20D.

【0046】

FIG. 2 is a block diagram showing a schematic configuration inside the base station 20 according to the first embodiment.

【0047】

The base station 20 shown in FIG. 2 includes a base station communication unit 21 that communicates with another base station 20, a mobile station wireless communication unit 22 that wirelessly connects to the mobile station 30 via a wireless line, and the entire base station 20. It has a base station side microcomputer 23 to control.

【0048】

The base station side microcomputer 23 receives a route control packet from the route cost measurement unit 23A that measures the route cost from its own station to another base station 20 and another base station 20, and uses this route control packet to make another base. By adding the route cost extraction unit 23B that extracts the base station route cost of station 20, the route cost measured by the route cost measurement unit 23A, and the base station route cost extracted by the route cost extraction unit 23B, The base station route cost calculation unit 23C that calculates the base station route cost of the station and the base station route that stores and holds the base station route cost of the own station calculated by this base station route cost calculation unit 23C. Communication between the cost memory unit 23D and the route control packet generation unit 23E that generates a route control packet to transmit the route cost for the base station stored in the base station route cost memory unit 23D to another base station 20. The base station selection signal generation unit 23F that generates a base station selection signal to transmit the base station path cost to the connectable mobile station 30, and the base station side control that controls the entire base station side microcomputer 23. It has a part 23G.

【0049】

The route cost may be, for example, the number of relays (number of hops) on the transmission path, propagation loss, signal power to noise ratio, etc., but will be described here as the number of relays.

【0050】

When the base station side microcomputer 23 of the first base station 20A receives a route cost calculation command for the base station from the relay server 12 in the route cost extraction unit 23B, the route cost measurement unit 23A receives the first base station 20A and the relay server. The route cost between 12 is measured, and this route cost is calculated by the base station route cost calculation unit 23C as the route cost for the first base station of the first base station 20A.

【0051】

When the route cost extraction unit 23B extracts the route cost for the first base station from the first base station 20A, the base station side microcomputer 23 of the second base station 20B uses the route cost measurement unit 23A to extract the route cost for the first base station 20A and the first base station 20A. The route cost between the second base station 20B is measured, and the route cost between the first base station 20A and the second base station 20B and the route cost for the first base station are added by the base station route cost calculation unit 23C. Therefore, it is calculated as the route cost for the second base station.

【0052】

When the base station side microcomputer 23 of the third base station 20C extracts the route cost for the third base station from the second base station 20B by the route cost extraction unit 23B, the route cost measurement unit 23A extracts the second base station 20B and The route cost between the 3rd base station 20C is measured, and the route cost between the 2nd base station 20B and the 3rd base station 20C and the route cost for the 2nd base station are added by the base station route cost calculation unit 23C. Therefore, it is calculated as the route cost for the third base station.

【0053】

When the base station side microcomputer 23 of the 4th base station 20D extracts the route cost for the 4th base station from the 3rd base station 20C by the route cost extraction unit 23B, the route cost measurement unit 23A extracts the 3rd base station 20C and The route cost between the 4th base station 20D is measured, and the route cost between the 3rd base station 20C and the 4th base station 20D and the route cost for the 3rd base station are added by the base station route cost calculation unit 23C. Therefore, it is calculated as the route cost for the 4th base station.

【0054】

FIG. 4 is an explanatory diagram showing a data structure of a route cost for a base station.

【0055】

The base station route cost 40 shown in FIG. 4 is composed of a communication destination name 40A, a base station name 40B, and a route cost content 40C. For example, the communication destination name 40A is the relay server 12, and the base station name 40B is the own station name and the route. Cost content 40C is the route cost between the relay server 12 and the base station 20.

【0056】

FIG. 3 is a block diagram showing a schematic configuration inside the mobile station 30.

【0057】

The mobile station 30 shown in FIG. 3 is a base station radio capable of communicating with base stations 20 such as the first base station 20A, the second base station 20B, the third base station 20C, and the fourth base station 20D through a wireless line. It has a communication unit 31 and a mobile station side microcomputer 32 that controls the entire mobile station 30.

【0058】

When the mobile station side microcomputer 32 receives the base station selection signal from the base station 20, the base station route cost extraction unit 32A for extracting the base station route cost included in the base station selection signal and the base station route When the cost is extracted, the route cost for the base station 32B23A, which measures the route cost with the currently connected base station 20 as the route cost for the base station, and the route cost for the base station and the route cost for the base station for each base station 20 The total route cost calculation unit 32C that calculates the total route cost by adding the route costs, the total route cost memory unit 32D that stores the total route cost calculated by the total route cost calculation unit 32C, and the relay server 12 and relay. When connecting, the optimum total route cost determination unit 32E that selects the base station 20 related to the optimum total route cost based on the total route cost stored in the total route cost memory unit 32D, and the entire mobile station 30 It has a mobile station side control unit 32F to control.

【0059】

FIG. 5 is an explanatory diagram showing the memory contents of the total route cost memory unit 32D.

【0060】

The total route cost memory unit 32D shown in FIG. 5 stores the base station name 50A and the total route cost content 50B for each base station 20.

【0061】

The base station route cost receiving means described in the claim is the base station wireless communication unit 31 and the base station route cost extraction unit 32A, and the base station route cost measuring means is the base station route cost measuring unit 32B. The route cost calculation means is the total route cost calculation unit 32C, the total route cost storage means is the total route cost memory unit 32D, the base station selection means is the optimum total route cost determination unit 32E, and the preliminary judgment route cost measurement means is the preliminary judgment route. The cost measurement unit 32G and the preliminary determination route cost storage means correspond to the preliminary determination route cost memory unit 32H.

【0062】

Further, the route cost measuring means for the base station described in the claim is the route cost measuring unit 23A, the route cost storing means for the base station is the route cost memory unit 23D for the base station, and the route cost transmitting means for the base station is the selection signal for the base station. It corresponds to the generation unit 23F and the mobile station wireless communication unit 22.

【0063】

Next, the operation of the wireless network 10 shown in the first embodiment will be described. FIG. 6 is a flowchart showing a series of processing operations on the base station 20 side related to the base station route cost memory processing in the wireless network 10 shown in the first embodiment.

【0064】

The base station route cost memory processing shown in FIG. 6 measures the route cost from each base station 20 to the relay server 12 according to the route control packet from the relay server 12, and uses each as the base station route cost. This is a process of storing and retaining each base station 20.

【0065】

In FIG. 6, the base station-side microcomputer 23 of the first base station 20A determines whether or not a route control packet from the relay server 12 has been received through the base station communication unit 21 (step S11). When the base station side microcomputer 23 receives the route control packet from the relay server 12, the base station side microcomputer 23 measures the route cost between the first base station 20A and the relay server 12 through the route cost measurement unit 23A (step S12).

【0066】

The base station side microcomputer 23 calculates the route cost between the first base station 20A and the relay server 12 as the route cost for the first base station through the route cost calculation unit 23C for the base station, and calculates the route cost for the first base station. It is stored in the route cost memory unit 23D for the base station (step S13).

【0067】

Further, the base station side microcomputer 23 generates a route control packet that propagates the route cost for the first base station through the route control packet generation unit 23E, and transmits this route control packet to the second base station through the base station communication unit 21. Send to 20B (step S14).

【0068】

When the base station side microcomputer 23 of the second base station 20B determines whether or not the route control packet from the first base station 20A has been received through the base station communication unit 21 (step S15). When the base station side microcomputer 23 receives the route control packet from the first base station 20A, the base station side microcomputer 23 extracts the route cost for the first base station from the route control packet from the first base station 20A through the route cost extraction unit 23B (step). S16).

【0069】

Further, the base station side microcomputer 23 measures the route cost between the first base station 20A and the second base station 20B through the route cost measurement unit 23A (step S17), and measures the route cost through the base station route cost calculation unit 23C. By adding the route cost for the first base station and the route cost for the first base station, the route cost for the second base station, which is the route cost between the relay server 12 and the second base station 20B, is calculated (step S18).

【0070】

When the base station side microcomputer 23 stores the route cost for the second base station in the route cost memory unit 23D for the base station (step S19), the route cost for the second base station is propagated through the route control packet generation unit 23E. A route control packet is generated, and this route control packet is transmitted to the third base station 20C through the base station communication unit 21 (step S20).

【0071】

When the base station side microcomputer 23 of the third base station 20C determines whether or not the route control packet from the first base station 20A has been received through the base station communication unit 21 (step S21). When the base station side microcomputer 23 receives the route control packet from the second base station 20B, the base station side microcomputer 23 extracts the route cost for the second base station from the route control packet from the second base station 20B through the route cost extraction unit 23B (step). S22).

【0072】

Further, the base station side microcomputer 23 measures the route cost between the second base station 20B and the third base station 20C through the route cost measurement unit 23A (step S23), and measures the route cost through the base station route cost calculation unit 23C. By adding the route cost for the second base station and the route cost for the second base station, the route cost for the third base station, which is the route cost between the relay server 12 and the third base station 20C, is calculated (step S24).

【0073】

When the base station side microcomputer 23 stores the route cost for the third base station in the route cost memory unit 23D for the base station (step S25), the route cost for the third base station is propagated through the route control packet generation unit 23E. A route control packet is generated, and this route control packet is transmitted to the fourth base station 20D through the base station communication unit 21 (step S26).

【0074】

When the base station side microcomputer 23 of the fourth base station 20D determines whether or not a route control packet from the third base station 20C has been received through the base station communication unit 21 (step S27). When the base station side microcomputer 23 receives the route control packet from the third base station 20C, the base station side microcomputer 23 extracts the route cost for the third base station from the route control packet from the third base station 20C through the route cost extraction unit 23B (step). S28).

【0075】

Further, the base station side microcomputer 23 measures the route cost between the third base station 20C and the fourth base station 20D through the route cost measurement unit 23A (step S29), and measures the route cost through the base station route cost calculation unit 23C. By adding the route cost for the third base station and the route cost for the third base station, the route cost for the fourth base station, which is the route cost between the relay server 12 and the fourth base station 20D, is calculated (step S30).

【0076】

The base station side microcomputer 23 stores the route cost for the fourth base station in the route cost memory unit 23D for the base station (step S31), and ends this processing operation.

【0077】

In this way, according to the base station route cost memory processing, the route cost between each base station 20 and the relay server 12 is calculated for each base station 20, and this route cost is used as the base station route cost. The memory can be retained on the side.

【0078】

FIG. 7 is a flowchart showing the processing operation on the mobile station 30 side related to the total route cost memory processing.

【0079】

The total route cost memory process shown in FIG. 7 is a process in which the mobile station 30 stores and holds the total route cost for calculating the route cost between the mobile station 30 and the relay server 12 for each base station 20.

【0080】

In FIG. 7, the mobile station side microcomputer 32 determines whether or not there is a base station 20 that can be received through the base station wireless communication unit 31 (step S41).

【0081】

When the mobile station side microcomputer 32 determines that there is a receivable base station 20, it receives a base station selection signal from the base station 20 (step S42). When the mobile station side microcomputer 32 receives the base station selection signal from the base station 20, it extracts the base station route cost from the base station selection signal through the base station route cost extraction unit 32A (step S43). When the mobile station side microcomputer 32 extracts the route cost for the base station, the mobile station side microcomputer 32 measures the route cost for the base station, which is the route cost between the base station 20 and the mobile station 30, through the base station route cost measuring unit 32B23A ( Step S44).

【0082】

The mobile station side microcomputer 32 calculates the total route cost by adding the route cost for the base station and the route cost for the base station related to the base station 20 through the total route cost calculation unit 32C (step S45), and the base. The total route cost for each station 20 is stored in the total route cost memory unit 32D (step S46), and the process proceeds to step S41 in order to determine whether or not there is a further receivable base station 20.

【0083】

As described above, according to the total route cost memory processing, the route cost between the mobile station 30 and the relay server 12 can be stored and held on the mobile station 30 side for each base station 20 as the total route cost.

【0084】

That is, when the mobile station 30 communicates with the relay server 12, the total route cost memory unit 32D refers to the total route cost being stored, and selects the base station 20 having the minimum total route cost.

【0085】

According to the first embodiment, each base station 20 measures the route cost for the base station between the own station and the relay server 12, and the mobile station 30 measures the route for the base station between the own station and each base station 20. The cost is measured, and the mobile station 30 calculates the total route cost for each base station 20 by adding the route cost for the base station and the route cost for the base station for each base station 20, and the total route cost for each base station 20. When the mobile station 30 relays and connects to the relay server 12, the base station 20 related to the optimum total route cost is selected based on the total route cost being stored. Therefore, the wireless network The entire resource can be used efficiently, and the mobile station 30 can obtain the optimum communication quality with the relay server 12.

【0086】

Further, according to the first embodiment, since the base station route cost is transmitted to the mobile station 30 by using the normally used base station selection signal, the base station route cost is transmitted. There is no need to secure a new channel.

【0087】

In the first embodiment, the route cost for the base station, the route cost to the base station, and the total route cost are used as the route information based on the number of relays, but the propagation loss, the signal power to the noise ratio, or the signal to the interference. If the route information is based on any one of the power ratios, more accurate base station selection can be obtained.

【0088】

Further, in the wireless network 10 shown in the first embodiment, the route cost is used as the number of relays to obtain the optimum total route cost among the total route costs stored in the total route cost memory unit 32D by the mobile station 30. The base station 20 to be involved is selected, but in the wireless network 10A shown in FIG. 8, since the number of relays of the first base station 20A and the fourth base station 20D is the same, there are multiple optimum total route costs. Is also possible.

【0089】

Therefore, in the wireless network 10A shown in the second embodiment, even if there are a plurality of such optimum total route costs, the optimum base station 20 is selected from among them. The configuration overlapping with the wireless network 10 shown in the first embodiment is designated by the same reference numeral, and the description of the configuration and operation will be omitted.

【0090】

FIG. 9 is a block diagram showing a schematic configuration inside the mobile station side microcomputer 32 in the wireless network 10A shown in the second embodiment, and FIG. 10 is an explanatory diagram showing the memory contents of the preliminary determination path cost memory unit 32H.

【0091】

The mobile station side microcomputer 32 shown in FIG. 9 communicates between its own station and the base station 20 to which communication can be connected, using a path cost of a type different from the path cost for the base station, for example, a propagation loss as a preliminary determination path cost. It has a preliminary determination route cost measurement unit 32G that measures for each connectable base station 20, and a preliminary determination route cost memory unit 32H that stores the preliminary determination route cost for each 20 connectable base stations. Based on the memory content 60 shown in FIG. 10, the optimum total route cost determination unit 32E determines the optimum total route cost when there are two optimum total route costs (1st base station 20A and 4th base station 20D). Select the base station 20 (4th base station 20D) related to the optimum preliminary judgment route cost based on the preliminary judgment route cost related to the base station 20 (1st base station 20A and 4th base station 20D). I did.

【0092】

As described above, according to the second embodiment, a route cost of a type different from the route cost for the base station between the own station and the base station 20 is measured for each base station 20 as a preliminary determination route cost. If there are a plurality of optimal total route costs, the base station 20 related to the optimum preliminary determination route cost is selected based on the preliminary determination route cost related to the base station 20 of these optimum total route costs. Therefore, it is possible to improve the selection accuracy of selecting the optimum base station 20.

【0093】

In the second embodiment described above, the propagation loss between the base station 20 and the mobile station 30 is used as the route cost for preliminary determination, but the route cost between the mobile station 30 and the relay server 12 is the same as the total route cost. The propagation loss of the above may be used as the path cost for preliminary determination.

【0094】

Further, in the second embodiment, the path cost for preliminary determination is set as the propagation loss, but the same effect can be obtained as the path information based on either the signal power to noise ratio or the signal to interference power ratio. Needless to say, it can be obtained.

【0095】

Further, in the second embodiment, the preliminary determination route cost is set to one, but when a plurality of route costs are used, the optimum base station 20 can be selected with higher accuracy.

【0096】

Further, in the second embodiment, the route cost for preliminary determination is the route cost between the base station 20 and the mobile station 30 (route cost for the base station), but the route between the relay server 12 and the mobile station 30 In terms of cost (total route cost), the optimum base station 20 can be selected with higher accuracy.

【0097】

Further, in the first and second embodiments described above, the case where a wired line is used between the 20 base stations has been described as an example, but when a wireless multi-pop network using a wireless line is used, a route is used. It is more effective to use path information based on any one of propagation loss, signal power to noise ratio, and signal to interference power ratio, instead of the number of relays.

【0098】

In the first and second embodiments described above, since the base station 20 is selected in consideration of the total route cost to the communication destination, efficiency is achieved without using wasteful network resources when viewed as a whole network. System operation becomes possible, and communication performance can be improved. In particular, in a wireless multi-hop network in which the quality difference depending on the route is considered to be large, the base station 20 that optimizes the quality up to the communication destination can be selected, so that the effect of improving the communication performance is great.

【0099】

Further, when there are a plurality of optimum total route costs, the base station 20 related to the optimum preliminary determination route cost is selected based on the preliminary determination route cost related to the base station 20 of these optimum total route costs. Therefore, for example, the transmission power of the mobile station 30 can be suppressed, and the radio wave interference of the entire network can be suppressed, and as a result, efficient use of wireless resources becomes possible. In particular, it is effective in a wireless multi-hop network where the difference in quality depending on the route is considered to be large.

【0100】

In the first embodiment, as shown in FIG. 1, the relay server 12 and each base station 20 are connected in series by a wireless line (relay server 12-base station 20A-base station 20B-base station 20C-base). The form of the station 20D) was explained. However, the present invention is not limited to the one in which the connection form between the communication network and each base station is in series. The present invention also relates to a case where the connection form between the communication network and each base station includes a plurality of nodes as in the Internet, and each base station is configured to select a node from a plurality of connectable nodes. Applicable. This will be described. FIG. 1 describes a case where the relay server 12 and each base station 20 are connected in series by a wireless line, and the base station 20A and the base station 20C are further connected. In this case, the base station 20C receives a route control packet recording the route cost for the base station from both the base stations 20A and 20B. Then, the base station 20C measures and measures the route cost between the own station (base station 20C) and the base station 20A and the route cost between the own station and the base station 20B, similarly to the mobile station in the present invention. The route cost and the route cost for the base station included in the route control packet are added, and the route having the smaller added route cost is selected. Further, in this case, the base station 20C transmits a route control packet to the base stations 20A and 20B in addition to the base station 20D on the downstream side. However, base stations 20A and 20B invalidate the route control packet received from base station 20C because the route cost between them is smaller than the route cost of the route via base station 20C. That is, the method of measuring the route cost in each of the base stations 20 is arbitrary, and differs depending on the form of the route formed between the base stations. Therefore, in the present invention, it is sufficient that each base station 20 holds the route cost for the base station, and any measurement method may be used.

【0101】

[Effect of the invention]

According to the base station selection method of the present invention configured as described above, each base station holds the route cost for the base station between the own station and the communication network, and the mobile station is between the own station and each base station. The route cost for base stations is measured, and the mobile station adds the route cost for base stations and the route cost for base stations for each base station to calculate the total route cost for each base station, and the total for each base station. In addition to storing the route cost, when the mobile station relays to the communication network, the base station related to the optimum total route cost is selected based on the stored total route cost, so the entire wireless network Resources can be used efficiently, and mobile stations can obtain optimum communication quality with the communication network.

【0102】

Further, according to the mobile station of the present invention, the route cost for the base station that can be connected to the communication and the route cost for the base station between the communication networks is received for each base station that can be connected to the communication, and is used for the base station between the own station and the base station. Measure the route cost, add the route cost for the base station and the route cost for the base station for each base station to calculate the total route cost for each base station, store the total route cost for each base station, and move. When a station relays to the communication network, the base station related to the optimum total route cost is selected based on the total route cost in storage, so the resources of the entire wireless network can be used efficiently. As a result, the mobile station can obtain the optimum communication quality with the communication network.

【0103】

Further, according to the base station of the present invention, the route cost for the base station between the own station and the communication network is stored, and the route cost for the base station in this storage is transmitted to the mobile station by the base station selection signal. Therefore, the mobile station can obtain the optimum communication quality with the communication network by efficiently using the resources of the entire wireless network.

[Simple explanation of drawings]

[Figure 1]

It is a system configuration diagram which shows the whole structure of the wireless network which shows the 1st Embodiment in the base station selection method of this invention.

[Figure 2]

It is a block diagram which shows the schematic structure inside the base station in the wireless network shown in 1st Embodiment.

[Fig. 3]

It is a block diagram which shows the schematic structure inside the mobile station in the wireless network shown in 1st Embodiment.

[Fig. 4]

It is explanatory drawing which shows the data structure of the route cost for the base station of the base station which concerns on 1st Embodiment.

[Fig. 5]

It is explanatory drawing which shows the memory content of the total path cost memory part of the mobile station which concerns on 1st Embodiment.

[Fig. 6]

It is a flowchart which shows a series of processing operations on the base station side related to the path cost memory processing for a base station in the wireless network shown in 1st Embodiment.

[Fig. 7]

It is a flowchart which shows the processing operation on the mobile station side which concerns on the total path cost memory processing in the wireless network shown in 1st Embodiment.

[Fig. 8]

It is a system configuration diagram which shows the whole structure of the wireless network shown in 2nd Embodiment.

[Fig. 9]

It is a block diagram which shows the whole structure inside the mobile station in the wireless network shown in 2nd Embodiment.

[Fig. 10]

It is explanatory drawing which shows the memory contents of the total path cost memory part and the preliminary determination path cost memory part in the mobile station in the wireless network shown in 2nd Embodiment.

[Fig. 11]

It is a system configuration diagram which shows the whole structure of the wireless network which adopted the conventional base station selection method.

[Explanation of symbols]

10 ...... wireless network, 10A ...... wireless network, 11 ...... communication network, 20 ...... base station, 22 ...... anti-mobile station Wireless communication unit (base station route cost transmission means), 23A ...... route cost measurement unit (base station route cost measurement means), 23D ...... base station route cost memory unit (base) Station route cost storage means), 23F ...... Base station selection signal generator (base station route cost transmission means), 30 ...... Mobile station, 31 ... Base station wireless communication unit (base station route cost receiving means), 32A ...... Base station route cost extraction unit (base station route cost receiving means), 32B ... Cost measurement unit (route cost measurement means for base station), 32C ...... total route cost calculation unit (total route cost calculation means), 32D ...... total route cost memory unit (total route cost) Storage means), 32E ...... Optimal comprehensive route cost determination unit (base station selection means), 32G ...... Preliminary judgment route cost measurement unit (preliminary judgment route cost measurement means), 32H. ..... Preliminary determination route cost memory unit (preliminary determination route cost storage means).