JP7237485B2 - Wireless communication system and wireless communication method - Google Patents

Description

The present invention relates to a wireless communication system and wireless communication method.

2. Description of the Related Art In a radio communication system in which a mobile station communicates with a plurality of base stations with different radio frequencies, communication interruptions occur during frequency switching (handoff). In order to reduce call interruptions, there is a wireless communication system in which base stations are synchronized and each base station transmits a signal of the same frequency at the same timing (for example, Patent Document 1).

JP 2015-144408 A

In a wireless communication system equipped with inter-base-station synchronization function, in which signals of the same frequency are transmitted from multiple base stations at the same timing, since all base stations transmit signals, a wireless communication system in which only one base station transmits signals is used. Power consumption is relatively high.
An object of the present invention is to provide a wireless communication system capable of reducing power consumption.

A brief outline of a representative one of the present invention is as follows.
That is, based on the preset area of each base station and the positional information obtained from the mobile station, the base station to which the signal needs to be transmitted is determined, and the transmission right is given only to the base station. As a result, the signal is transmitted only from the base stations to which transmission rights have been granted, rather than from all base stations.

According to the wireless communication system, power consumption can be reduced.

1 is a diagram showing an example of a schematic configuration of a wireless communication system of an embodiment; FIG. 2 is a diagram showing an example of an operation sequence of the radio communication system of FIG. 1; FIG.

A wireless communication system according to an embodiment has a function of synchronizing between base stations, and transmits signals of the same frequency at the same timing from a plurality of base stations. The radio communication system grants transmission rights only to base stations that require transmission, based on "preset areas of each base station" and "position information acquired from mobile stations." Based on the area information of each base station and the location information of the mobile station, it is possible to determine which base station needs to transmit a signal, thereby reducing power consumption by not transmitting signals from unnecessary base stations can be done.

More specifically, a wireless communication system receives position information from a mobile station, obtains the position and direction of movement (latitude and longitude on the time axis) of the mobile station, and determines the position and direction of movement of the mobile station and the location of the base station. Based on location information (area of each base station set in advance), (A) the base station that the mobile station is currently serving, and (B) the base station that the mobile station will serve next (after a certain period of time). , (C) determine the base stations that will not be affiliated either at the present time or after a certain period of time, and grant transmission rights to the base stations (A) and (B). If it is determined that the mobile station will not move, the base station (B) does not have to be granted the transmission right.

An embodiment will be described below with reference to FIGS. FIG. 1 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment.

The wireless communication system 1 of the embodiment includes devices and facilities such as a command facility 10, a line control device 20, a base station 30, a mobile station 40, and the like. A radio communication system 1 has a function of synchronizing between base stations, and transmits signals of the same frequency at the same timing from a plurality of base stations.

The command facility 10 is installed in the command center and connected to the line control device 20 to operate the radio communication system 1. The command facility 10 is a device for operating the radio communication system 1, and is used for voice input/output, data (images, information indicating the position of the mobile station, etc.). input, process, display, etc. The area (service area) covered by each base station 30 is preset in the command facility 10 . The command facility 10 determines the base station 30 that requires transmission to communicate with the mobile station 40 based on the location information obtained from the mobile station 40 and the area covered by each base station 30, and determines the base station 30 that requires transmission. The base station 30 is notified to the line control device 20 .

The command facility 10 is connected to the line controller 20 as described above. Also, the line controller 20 is connected to a plurality of base stations 30 under its control. In this embodiment, five base stations 30 (#1) to (#5) that perform radio communication with a mobile station 40 are connected to the line control device 20, and these base stations 30 are controlled. The number of base stations 30 is not limited to five, but is set based on the spatial size of the wireless communication system and the distance between base stations.

The line control device 20 periodically collects the location information of the mobile station 40 via the base station 30, transfers the collected information to the command facility 10, and, according to the decision of the command facility 10, permits or prohibits the transmission of the base station 30. Indicate permission. For example, the transmission right is granted to the base station 30 by transmitting to the base station 30 information in which a transmission permission flag is set. Further, by transmitting to the base station 30 information from which the transmission permission flag has been removed, the transmission right granted to the base station 30 is released. The transmission right may be canceled when a predetermined time has passed since the time the transmission right was granted or the time the base station transmitted the signal. The line control device 20 has a control section (not shown) having a CPU (Central Processing Unit) and a base station interface section (not shown). The base station 30 also has a control unit (not shown) having a CPU, a radio unit (not shown), and a radio antenna 31 .

The base station 30 wirelessly communicates with a mobile station 40 existing within its own service area (broken line in FIG. 1). At this time, based on the transmission right transmitted from the line control device 20, it is determined whether or not to transmit the signal. That is, only the base station 30 to which the transmission right is granted transmits the signal.

The mobile station 40 is a wireless communication terminal that can be freely moved by being mounted on a vehicle or being carried, and performs wireless communication with the base station 30 whose location is included in the service area. The mobile station 40 has a GPS antenna (not shown), a GPS module (not shown), a control unit (not shown) having a CPU, a radio unit (not shown), and a radio antenna 41. there is The mobile station 40 acquires position information from the GPS module, and periodically transmits its own position information to the base station 30 in response to a request from the line control device 20 via the base station 30 . The mobile station 40 also transmits position information when the power is turned on.

The command facility 10 determines which base station 30 to grant transmission rights based on the location information of the mobile station 40 and the area covered by each base station 30 . In FIG. 1, the mobile station 40 exists in the area of the base stations 30(#1) and 30(#2). At this time, the command facility 10 can determine that it is necessary to transmit signals only from the base stations 30 (#1) and 30 (#2) in which the mobile station is present in the area, rather than from all base stations. . In addition, when the position information of the mobile station 40 is collected periodically, the moving direction and moving speed of the mobile station 40 are calculated from the differentiation, and depending on the case, the destination base station (base station 30 (#3)) may also be determined to need to be sent. That is, when the position of the mobile station 40 is close to the position of the base station 30 (#3), the base station (#3) is determined as the destination base station. In a wireless communication system in which the mobile station 40 moves only in a certain direction, such as a highway, the base station 30 is arranged along the highway, so the next mobile station 40 will be under its umbrella. Station 30 is established. Therefore, the base station 30 to which the line control device 20 grants the transmission right is the base station 30 under the control of the mobile station 40 and the base station 30 to which the mobile station 40 moves. Station 30 is not granted the right to transmit. Further, when the moving speed of the mobile station 40 is low (below a predetermined threshold value), for example, during traffic jams, the destination base station 30 may not be granted the transmission right. That is, when the moving speed 40 of the mobile station 40 is greater than a predetermined threshold, the transmission right is granted to the destination base station 30 . As a result, the present system predicts the destination base station 30 of the mobile station 40 and grants the transmission right only to the base station 30 served by the mobile station 40 and the predicted base station 30 . As a result, the power consumption of the system can be further suppressed as compared with the method of granting the transmission right only to the base stations 30 that are close to each other. Note that the line control device 20 may determine the base station to which the transmission right is granted.

Next, the flow of operation of the radio communication system 1 will be described with reference to FIG. FIG. 2 is a diagram showing an operation sequence of the radio communication system of FIG.

First, the user provides the command facility 10 with information on the areas covered by each base station 30 so that the area is recognized in advance (step S1). During system operation, the mobile station 40 acquires its own location information from the GPS, and periodically transmits the location information and ID information of the mobile station 40 to the line controller 20 and the command facility 10 via the base station 30. (step S2).

When the user actually performs a call operation (step S3) with the mobile station 40, the command facility 10, based on the "preset area of each base station" and "location information of the mobile station", The base station 30 that needs to transmit the signal is determined, and the command facility 10 notifies the determination to the line controller 20 (step S4).

Next, the line controller 20 grants the transmission right only to the base station 30 that requires transmission, and then instructs the transmission operation (step S5). Here, the base station 30 that requires transmission is referred to as "A base station", and the base station 30 that does not require transmission is referred to as "B base station". The A base station enters transmission operation, and as a result, realizes communication with the mobile station 40 (step S6). On the other hand, the B base station does not take any transmission action. As a result, it is possible to transmit signals only from necessary base stations instead of from all base stations, and reduce power consumption by the amount of base station 30 (B base station in this example) that does not require transmission. . Note that the base stations 30 that do not require transmission are in a state of waiting for reception.

The invention made by the present inventors has been specifically described above based on the embodiments and examples, but it should be noted that the present invention is not limited to the above-described embodiments and examples, and can be modified in various ways. Not even.

Reference Signs List 1 Radio communication system 10 Command facility 20 Line controller 30 Base station 40 Mobile station

Claims (6)

A wireless communication system comprising a mobile station, a plurality of base stations transmitting signals to the mobile station, a line control device connected to the base station, and a command facility connected to the line control device. hand,
The command facility receives position information from the mobile station, obtains a direction of movement of the mobile station based on the position information, and determines the direction of movement of the mobile station based on the direction of movement of the mobile station and the position information of the base station. determining the destination base station of the station, and notifying the line control device of the destination base station;
The line control device grants a transmission right to the destination base station and the base station under which the mobile station is affiliated ,
A radio communication system in which the base station transmits a signal to the mobile station when the transmission right is granted. In the wireless communication system of claim 1,
The radio communication system, wherein the line control device cancels the transmission right when a predetermined period of time has elapsed after granting the transmission right. In the wireless communication system of claim 1 or claim 2,
A radio communication system in which the command facility obtains the moving speed of the mobile station based on the location information of the mobile station, and grants a transmission right to a destination base station when the moving speed is greater than a predetermined threshold. A wireless communication method for transmitting a signal from a base station to a mobile station,
obtaining a moving direction of the mobile station based on the location information of the mobile station; and determining a destination base station of the mobile station based on the moving direction of the mobile station and the location information of the base station. a wireless communication method comprising the steps of: granting a transmission right to the target base station and the base station under which the mobile station is served; and transmitting a signal from the base station granted the transmission right. . In the wireless communication method of claim 4,
A wireless communication method, comprising the step of canceling the transmission right when a predetermined time has elapsed after granting the transmission right. In the wireless communication method of claim 4 or claim 5,
Wireless communication comprising the steps of determining the moving speed of the mobile station based on the location information of the mobile station, and granting a transmission right to a destination base station when the moving speed is greater than a predetermined threshold. Method.

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