JP2001298762A - Mobile communication system and mobile station - Google Patents

Abstract

(57) [Problem] To perform a reliable handover in a mobile communication system in which base stations are continuously arranged on a line. A base station notifies a mobile station of a communication channel (frequency) of a next base station by providing an overlapping communication area between adjacent base stations. While communicating with the current base station, the mobile station can receive the pilot slot from the next base station on the predicted communication channel, and can receive the pilot slot without fail, for example, successfully receiving the pilot slot continuously. Handover processing is performed when the A more reliable handover can be realized as compared with a method of performing a handover by observing the radio wave intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile station in which a plurality of base stations are arranged on a line such as a road, and continuous mobile communication is enabled for a mobile station traveling on the line by a communication area constituted by the base stations. The present invention relates to a communication system, and particularly to realizing a handover when a mobile station shifts a communication area of a base station.

[0002]

2. Description of the Related Art For the purpose of providing traffic information, driving assistance, automatic driving, etc., base stations are continuously arranged along a road,
A mobile communication system that performs communication with a mobile station (vehicle) by forming a continuous communication area has been developed. In these mobile communication systems, a handover process is required when the mobile station moves to a communication area formed by base stations.

[0003] As a conventional mobile communication system for realizing a handover, a mobile station measures the radio wave intensity at the mobile station, detects the boundary of a communication area formed by each base station, and performs the handover. was there. Japanese Patent Application Laid-Open No. H10-108237 discloses a mobile communication system that implements handover by measuring the radio wave intensity and detecting the boundary of the communication area. Here, the mobile station observes the current signal strength of the communication area of the base station, detects the point where the signal strength is maximum, and then calculates the moving distance of the mobile station from the point where the signal strength is maximum. Then, the handover is performed when the moving distance reaches the vicinity of the boundary of the communication area of the base station.

[0004] The following describes the conventional technology with reference to the drawings.
Give an explanation.

FIG. 10 is a configuration diagram of a conventional mobile communication system.

In FIG. 10, reference numerals 1001 denote base stations A and 1;
002 is a base station B, and 1003 is a mobile station.

The operation of the conventional technique configured as described above will be described below.

As shown in FIG. 10, in the prior art, the base stations are continuously arranged so that the communication area of the base station is continuous without any gap, so that continuous communication with the mobile station on the road is possible. I will provide a. In the communication area of the base station A,
The mobile station performs bidirectional communication with the base station A, and in the communication area of the base station B, the mobile station can perform bidirectional communication with the base station B. In these mobile communication systems, F
A plurality of channels are prepared by DMA, TDMA, and CDMA, and adjacent base stations need to use different channels. Here, it is assumed that FDMA is used, and adjacent base stations use different frequencies. When the mobile station moves from one base station A cell to the next base station B cell, a handover process is required.

The curve in FIG. 10 shows the relationship between the distance and the electric field strength. The electric field strength is the strongest immediately below the base station. Utilizing the fact that the radio wave intensity becomes maximum when the mobile station passes directly below the base station, handover is performed at a point where the mobile station has moved a certain distance L from the point where the radio wave intensity has become maximum. By defining the fixed distance L such that the point moved by the fixed distance L is at the boundary between one base station and the next base station as shown in FIG. 10, the mobile station can perform handover without any trouble. The fixed distance L may be determined in advance and stored in the mobile station, or L of the base station may be communicated from the base station to the mobile station. The measurement of the moving distance in the mobile station is performed by a known method such as a method of detecting the rotation of a wheel by a wheel speed sensor or a method of using a GPS.

Next, the handover procedure will be described.
The mobile station issues a handover request to the base station A when reaching the point at the distance L. The handover request includes a mobile station ID that uniquely identifies the mobile station. Base station A and base station B are connected by wire, and base station A that has received the handover request transmits handover data to the next base station B. The handover data includes the ID of the mobile station that performs the handover, and the number of the data packet that has not been received when the data packet is taken over. By using these data, the next base station B can communicate with the mobile station following the base station A. The base station B having received the handover data notifies the base station A of the completion of the handover, and the base station A notifies the mobile station of the completion of the handover. The mobile station that has received the handover completion switches the communication channel to the frequency of the next base station B,
It communicates with the base station B.

[0011]

However, the above configuration has the following problems.

Generally, in mobile communication, the instantaneous value fluctuation of the radio wave intensity is large due to the influence of multipath and the like, especially when the moving speed of the mobile body is high.
Therefore, the method of detecting the cell boundary based on the radio wave intensity becomes unstable, and the handover may be performed before or after the point where the handover is originally performed, or in some cases, the handover may be repeated a plurality of times. Become stable. For example, in the conventional handover method, if an error occurs at the point where the radio field intensity is maximum, the mobile station and the next base station are moved at a point where the mobile unit moves a predetermined distance determined from the time point when the radio field intensity is maximum. May not be able to communicate.

In view of the above, it is an object of the present invention to reliably perform handover in a mobile communication system in which base stations are continuously arranged on a line.

[0014]

In the mobile communication system according to the first aspect of the present invention, an overlapping area is set in a communication area constituting a base station arranged on a line and a communication area constituting a next base station. At the same time, the mobile station communicates with the current base station, receives and decodes a pilot slot from the next base station, and performs handover when the pilot slot can be received two or more times in succession.

With the mobile communication system according to the first aspect of the present invention, it is possible to perform a handover more reliably than when a handover is performed by measuring a radio field intensity at a mobile station.

In the mobile communication system according to the second aspect of the present invention, an overlap area is set in a communication area constituting a base station arranged on a line and a communication area constituting a next base station. At the same time as communicating with the base station, receiving and decoding the pilot slot from the next base station,
Handover is performed at the point in time when a threshold number of times can be received during reception of a fixed number of pilot slots.

With the mobile communication system according to the second aspect of the present invention, it is possible to perform a handover more reliably than by performing a handover by measuring a radio field intensity at a mobile station.

In the mobile communication system according to a third aspect of the present invention, in the mobile communication system according to the first or second aspect of the present invention, the mobile station transmits a handover request to the next base station.

In the mobile communication system according to the third aspect of the present invention, even when the mobile station is passing through the base station, the next base station receives the handover request, so that the handover can be performed more reliably.

According to a fourth aspect of the present invention, in a mobile communication system in which a plurality of antennas for transmitting and receiving the same radio wave are arranged continuously on a line, one or more base stations are arranged at a boundary between adjacent base stations. The antenna is used in common or the communication area of one or more antennas is overlapped, and handover is performed by the handover method according to the first and second aspects of the present invention.

[0021] In the mobile communication system according to the fourth aspect of the present invention, the overlapping area of the adjacent base stations can be provided more stably, and the handover method according to the first and second aspects of the present invention can function more effectively. Can be.

[0022]

(Embodiment 1) A mobile communication system according to Embodiment 1 of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a mobile communication system according to Embodiment 1 of the present invention. In FIG. 1, 11 is a control station, 12 is a base station A, and 13 is a base station B
, 14 is a base station C, 15 is a base station D, 16 is a mobile station, and 17 is a road.

The operation of the mobile communication system according to the present embodiment configured as described above will be described below.

As shown in FIG. 1, in the mobile communication system according to the present embodiment, base stations are continuously arranged along a road 17, and the base stations transmit and receive radio waves. The communication area of the base station is set so that an overlapping area occurs with the adjacent base station. Here, the communication area is an area where the base station and the mobile station can communicate. As a result, the mobile station traveling on the road 17 can continuously and temporally communicate with the base station. Although the communication content is not particularly limited, for example, there are road traffic information, weather information, and the like.

Each base station is connected to the control station by wire,
Each base station is centrally controlled by a control station, for example. Since cells constituting adjacent base stations interfere with each other, radio waves having different frequencies are used, and the same frequency is reused in base stations distant to some extent. In FIG. 1, the repetition frequency is 3, base station A uses F1, base station B uses F2, base station C uses F3, and base station D uses the same F1 as base station A.

When the mobile station moves and moves to a base station having a different communication area, a handover is required. In the present embodiment, overlapping communication areas are set between communication areas of adjacent base stations as described above. In the present embodiment, the traveling direction of the mobile station is one direction. Needless to say, the road 17 may be curved.

Next, the configurations of the base station and the mobile station will be described. FIG. 2 is a configuration diagram of a mobile station and a base station according to Embodiment 1 of the present invention. In FIG. 2, reference numeral 21 denotes a mobile station, which is an antenna 211, a receiving device 212, a control device 213,
The base station 22 includes a transmitting device 214, and includes an antenna 221, a receiving device 222, a control device 223, a wired transmitting / receiving device 224, and a transmitting device 225.

The mobile station 21 includes an antenna 211, a receiving device 212 for receiving data from the base station using the antenna 211, a transmitting device 214 for transmitting data to the base station using the antenna 211, and a receiving device 212. The control device 213 is configured to transmit and receive data to and from a base station in a predetermined procedure using the transmitting device 214.

The base station 22 includes an antenna 221, a receiving device 222 for receiving data from the mobile station using the antenna 221, a transmitting device 225 for transmitting data to the mobile station using the antenna 221, and a receiving device 222. A control device 223 that performs data transmission and reception with a mobile station using a transmission device 225 according to a predetermined procedure and performs communication with a control station using a wired transmission and reception device 224, and performs data transmission and reception with the control station. It is configured by a wired transmission / reception device 224. The base station transmits and receives data to and from the control station by the wired transmission / reception device 224. The control station transmits data to be transmitted to the mobile station, receives data from the mobile station, and transmits control data to each base station.

The communication system in this embodiment is a master-slave system in which a base station is a master and a mobile station is a slave. FIG. 3 shows a communication frame configuration according to the present embodiment. In FIG. 3, reference numeral 31 denotes a communication frame. FIG. 3 shows one communication frame, and communication is performed by continuously exchanging the communication frame 31 between the base station and the mobile station.

The frame control slot is a slot for controlling the entire frame transmitted from the base station to the mobile station. The data slot is a slot for transmitting and receiving data between the base station and the mobile station. The frame control slot includes the ID of the base station, the frequency data of the next base station, the transmission timing of the frame control slot, and the assignment of the data slot in the frame (uplink slot or downlink slot, ID of the mobile station to be transmitted / received). ) Data is included. Here, the uplink slot is a slot from the mobile station to the base station, and the downlink slot is a slot from the base station to the mobile station. By receiving the frame control slot from the base station, the mobile station learns the mobile station ID and slot direction of each data slot in the frame and transmits and receives data to and from the base station.

The mobile station request slot is a slot for transmitting an uplink data slot request from the mobile station to the base station, a handover request, and the like to the base station. The uplink data slot request is defined to request the base station to allocate an uplink data slot. On the other hand, a handover request is defined to request a handover from a mobile station to a base station. When the mobile station needs to transmit a slot requested by the mobile station, the mobile station randomly selects a slot and performs transmission. The transmission of the mobile station requested slot by the mobile station may occur at an arbitrary timing and thus may collide, but when the collision occurs, the mobile station retransmits.

FIG. 4 shows a communication sequence according to the first and second embodiments of the present invention. In FIG. 4, reference numeral 41 denotes a communication sequence.

The communication sequence 41 indicates a communication sequence between the base station and the mobile station for one frame. The base station transmits a frame control slot to the mobile station, and the mobile station that has received the frame knows the transmission / reception timing of the data slot from the contents of the frame control slot. In the communication sequence 41, data slot 1 is used for transmission from the base station to the mobile station 1, data slot 2 is used for transmission from the base station to the mobile station 2, data slot 3 is used for transmission from the base station to the mobile station 3, Slot 4 is used for transmission from mobile station 2 to the base station. Further, in the mobile station request slot, the mobile station 2 makes an uplink data slot request in the mobile station request slot 3 and the mobile station 3 makes a mobile station request slot in the mobile station request slot 3.

The handover method according to the present embodiment based on the above communication frame will be described below.

In the present embodiment, the mobile station receives a pilot slot from the next base station during communication with a certain base station (in this embodiment, a frame control slot is used as a pilot slot), and Handover is performed when it is determined that the signal can be received successfully consecutively (two or more times) and the signal can be reliably received. Usually, a base station transmits pilot slots periodically. The frequency of the next base station is described as data in the frame control slot of the current base station. The base station receiving the handover request from the mobile station notifies the mobile station of the completion of the handover after transmitting the mobile station ID and the unreceived data packet number to the next base station, and the mobile station starts communication with the next base station. I do.

These handover methods will be described in detail below.

In this embodiment, the criterion that the mobile station can reliably receive the next base station is to continuously receive N (N is a natural number of 2 or more) frame control slots of the next base station. Suppose we were able to do it. Successful reception can be performed in a known manner by checking the error of the frame control slot. In the present embodiment, a communication area overlapping with the communication area of an adjacent base station is set. Therefore, when the mobile station enters the overlapping area, it is considered that the mobile station can surely receive the pilot slot of the next base station. Therefore, the handover can be performed normally if the number N of continuous reception successes, which is the criterion for handover, is set to a value appropriate for the number of pilot data that can be received in the time when the mobile station passes through the overlapping communication area. .

The handover sequence using these criteria will be described below.

FIG. 5 shows a handover sequence.
In FIG. 5, reference numeral 51 denotes a handover sequence.

As shown in FIG. 5, the mobile station receives the next frame control slot of base station B while communicating with base station A. When this frame control slot can be received N consecutive times, the mobile station assumes that the mobile station has entered the communication area of the next base station, and transmits a handover request to the current base station A. The handover request is made in the mobile station request slot described with reference to FIG. The base station A that has received the handover request transmits the takeover data to the base station B. The transfer data includes a mobile station ID, a transmission / reception completion packet number, and the like. Based on these takeover data, the next base station B can continue to communicate with the mobile station that has moved. After transmitting the handover data, the base station A transmits a handover completion to the mobile station. Handover completion is transmitted in a data slot. The mobile station that has received the handover completion can start communication with the next base station B.

As described above, in the system in which an overlapping area is provided in the communication area between adjacent base stations and the mobile station side performs the handover when the pilot slot of the next base station can be reliably received, the handover Is performed, the mobile station has certainly entered the communication area of the next base station, so that a more reliable handover can be realized as compared with the method of comparing the electric field strengths.

In the present embodiment, the handover is performed based on the criterion that the pilot slot can be continuously received a fixed number of times. Judgment criteria are conceivable.

In this embodiment, the mobile station transmits a handover request when performing a handover from the mobile station to the base station with which communication is currently being performed. However, the mobile station may transmit a handover request to the next base station. Conceivable. The handover sequence in this case is shown in the figure.

FIG. 6 shows a handover sequence.
In FIG. 6, reference numeral 61 denotes a handover sequence.
When the mobile station issues a handover request to the next base station as in the handover sequence 61, the next base station B
Requests the current base station A to take over data specifying the mobile station, and the current base station A transmits the takeover data to the next base station B in response to the request. If the mobile station issues a handover request to the next base station in this manner, handover can be reliably performed even when the mobile station moves in the traveling direction and has left the communication area of the current base station.

Although the present embodiment has been described with reference to a mobile communication system in which a base station is arranged on a road and a mobile station (vehicle) moves on a line, the base station is arranged on a line. The present invention is effective for all mobile communication systems that perform the communication.

Further, in the embodiment of the present invention, the case where the traveling direction of the mobile station is one direction has been described as an example.
The present invention is also effective when the traveling directions are two directions (when the traveling directions of the two mobile stations are different). When the traveling directions are two directions, the base station transmits the communication channels (frequency) of the two adjacent base stations and the data of the directions of the two base stations, and the mobile station that receives the data transmits the communication channel (frequency) of the two base stations. Among them, it is determined which is in the traveling direction of the own station, and the pilot slot of the communication channel of the next base station is received and handover is performed. At this time, the mobile station needs a means for detecting the direction.

(Embodiment 2) Hereinafter, a mobile communication system according to Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 7 is a configuration diagram of a mobile communication system according to Embodiment 2 of the present invention. 7, reference numeral 71 denotes a control station, 72 denotes a base station A, and 73 denotes a base station B.
Where 74 is a base station C, 75 is a mobile station, and 76 is a road.

The operation of the mobile communication system of the present embodiment configured as described above will be described below.

In the first embodiment, an overlapping area is provided in the communication area of the two base stations, and the mobile station receives the pilot slot of the next base station while communicating with the current base station in this area. The execution determination of the handover was performed according to.

However, according to the method of Embodiment 1, the overlapping area of the communication area is located far from the antenna of the base station, and when the communicable distance changes due to the influence of multipath, fading, etc., the size of the overlapping area becomes large. If the overlap area is reduced and the overlap area is reduced, handover may not be successful.

Therefore, the communication area in the base station is constituted by transmitting and receiving the same radio wave from a plurality of antennas, and the antennas are shared between the base stations at the boundary of the adjacent base stations, so that the overlap between adjacent base stations is achieved. A mobile communication system that stably sets an area is the mobile communication system shown in FIG. In FIG. 7, a plurality of antennas are arranged along a road, and the same radio wave is transmitted and received from an antenna belonging to a certain base station. In FIG. 7, one antenna at the boundary between base stations is shared by adjacent base stations, and radio waves of the two base stations are transmitted and received. From the antenna existing at the boundary between the base station A and the base station B in FIG.
2 transmit and receive radio waves. According to such a configuration, F1,
A cell formed by an antenna transmitting and receiving both radio waves of F2 can be clearly defined as an overlapping area of adjacent base stations. Therefore, the mobile station receives the pilot slot of the next base station in the overlap area, and
The handover indicated by can be reliably performed. Note that the communication method and the handover method in the present embodiment are described in Embodiment 1 described with reference to FIGS.
The same method as described above may be used.

Next, the configuration of the base station according to the present embodiment will be described with reference to the drawings.

FIG. 8 is a configuration diagram of a base station according to Embodiment 2 of the present invention. 8, 81, 83, 85
Is an antenna, 82, 84, 86 are O / E converters, 87
Is an E / O conversion device, 88 is a receiving device, 89 is a control device,
810 is a wired transmission / reception device, and 811 is a transmission device.

The difference from the base station 22 described in the first embodiment is that a plurality of antennas are provided and the transmitting device and the receiving device of the base station are connected to the antennas by optical fibers. The same radio waves are radiated from the antennas, and each antenna receives radio waves of the same frequency. The antenna and the optical fiber are connected by an O / E converter to convert an optical signal and an electric signal. On the other hand, the optical fiber, the receiver, and the transmitter are E / O
They are connected by a converter and convert optical signals and electrical signals. As described above, a base station that transmits and receives the same radio signal from a plurality of antennas is realized.

As described above, an overlapping communication area is provided between adjacent base stations, and the mobile station can receive the pilot slot of the next base station in the overlapping communication area and can reliably receive the pilot slot. In a mobile communication system that performs handover processing in the case of a base station, a base station having a plurality of antennas for transmitting and receiving the same radio wave along a road is arranged, and by sharing an antenna between adjacent base stations, a stable overlapping communication area is formed. It is possible to perform a more stable handover by installing the device.

Although the number of antennas shared between adjacent base stations is one in the present embodiment, the present invention is also effective when one or more antennas are shared between adjacent base stations.

It is also conceivable that adjacent base stations do not share antennas and overlap one or more antenna areas to create overlapping communication areas. This will be described with reference to the drawings.

FIG. 9 is a configuration diagram of a mobile communication system according to Embodiment 2 of the present invention. 9, reference numeral 91 denotes a control station, 92 denotes a base station A, and 93 denotes a base station B.
Where 94 is a base station C, 95 is a mobile station, and 96 is a road.

In FIG. 9, as in FIG.
The same radio waves are transmitted and received from a plurality of antennas along the top, but the antennas are not shared between adjacent base stations, and the rightmost antenna of base station A is arranged on the right side of the leftmost antenna of base station B. . As a result, one or more antenna areas can be set as overlapping communication areas between adjacent base stations, and stable handover can be performed in the overlapping communication areas.

[0063]

As described above, the first aspect of the present invention is as follows.
In the mobile communication system according to the invention of the present invention, an overlapping area is set in a communication area forming the base station and a communication area forming the next base station, and the mobile station communicates with the current base station and simultaneously sets the next base station. A pilot slot from a station is received and decoded, and handover is performed when pilot slots can be received two or more times in succession. With the mobile communication system according to the first aspect of the present invention, the handover can be performed more reliably by measuring the radio wave intensity at the mobile station than in the case where the handover is performed.

In the mobile communication system according to the second aspect of the present invention, an overlap area is set in a communication area forming the base station and a communication area forming the next base station, and the mobile station communicates with the current base station. At the same time, the pilot slot from the next base station is received and decoded, and handover is performed when it becomes possible to receive the threshold number of times during pilot slot reception. With the mobile communication system according to the second aspect of the present invention, the handover can be performed more reliably by measuring the radio wave intensity at the mobile station than in the case where the handover is performed.

In the mobile communication system according to the third aspect of the present invention, in the mobile communication system according to the first or second aspect of the present invention, the mobile station transmits a handover request to the next base station. In the mobile communication system according to the third aspect of the present invention, the handover can be performed more reliably because the next base station receives the handover request even when the mobile station is passing through the base station.

According to the fourth aspect of the present invention, in a mobile communication system in which a plurality of antennas for transmitting and receiving the same radio wave are arranged along a road, one base station is provided at a boundary between adjacent base stations in a mobile communication system. The above antennas are used in common or the communication area of one or more antennas is overlapped, and handover is performed by the handover method according to the first and second inventions of the present application. In the mobile communication system according to the fourth aspect of the present invention, the overlapping area of adjacent base stations can be provided more stably, and the handover method according to the first and second aspects of the present invention can function more effectively.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile communication system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a mobile station and a base station according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing a communication frame configuration according to the first and second embodiments of the present invention.

FIG. 4 is a diagram showing a communication sequence according to the first and second embodiments of the present invention.

FIG. 5 shows a handover sequence.

FIG. 6 shows a handover sequence.

FIG. 7 is a configuration diagram of a mobile communication system according to a second embodiment of the present invention.

FIG. 8 is a configuration diagram of a base station according to Embodiment 2 of the present invention.

FIG. 9 is a configuration diagram of a mobile communication system according to Embodiment 2 of the present invention.

FIG. 10 is a configuration diagram of a conventional mobile communication system.

[Explanation of symbols]

 11, 71, 91 Control station 12, 72, 92, 1001 Base station A 13, 73, 93, 1002 Base station B 14, 74, 94 Base station C 15 Base station D 16, 21, 75, 95, 1003 Mobile station 211,221,81,83,85 Antenna 212,222,88 Receiving device 213,223,89 Control device 214,225,811 Transmitting device 22 Base station 224,810 Wired transmitting / receiving device 31 Communication frame 41 Communication sequence 51,61 Handover Sequence 82, 84, 86 O / E converter 87 E / O converter

Continued on the front page (72) Inventor ▲ Taka ▼ Hitoshi Ikai 1006 Kazuma Kadoma, Kazuma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 5K067 AA33 BB03 DD25 DD34 EE02 EE10 EE16 EE44 EE56 EE71 GG03 GG11 JJ35 JJ39 KK39

Claims (10)

[Claims] 1. A mobile communication system for communicating between a base station and a mobile station by continuously arranging base stations on a line and forming a series of communication areas on the line, wherein the base station comprises: Set overlapping communication areas between adjacent base stations, transmit pilot slots to mobile stations,
When a handover request is received from the mobile station, the mobile station performs a handover process. The mobile station communicates with the current base station, receives a pilot slot of the next base station, and continuously receives the pilot slot two or more times. A mobile communication system for transmitting a handover request to a base station when the mobile communication system is able to do so. 2. A mobile station that communicates with a base station continuously arranged on a line, communicates with a current base station, receives a pilot slot of a next base station, and repeats the pilot slot twice. A mobile station, which transmits a handover request to a base station when reception is continuously possible. 3. A mobile communication system for communicating between a base station and a mobile station by continuously arranging base stations on a line and forming a series of communication areas on the line, wherein the base station comprises: Set overlapping communication areas between adjacent base stations, transmit pilot slots to mobile stations,
When a handover request is received from a mobile station, a handover process is performed.The mobile station communicates with the current base station, receives a pilot slot of the next base station, and has a threshold when receiving the pilot slot a certain number of times. A mobile communication system, wherein a handover request is transmitted to a base station when the number of times of reception is equal to or greater than a value. 4. A mobile station communicating with a base station continuously arranged on a line, communicating with a current base station, receiving a pilot slot of a next base station, and performing a predetermined number of times of the pilot slot. A mobile station for transmitting a handover request to a base station when the number of times of reception is equal to or greater than a threshold value. 5. The mobile communication system according to claim 1, wherein data of a communication channel of a next base station is transmitted from the base station to the mobile station. 6. The mobile station according to claim 2, wherein data of a communication channel of the next base station is received from the base station, and a pilot slot of the next base station is received based on the data. 7. A communication system in which one base station arranges a plurality of antennas on a line and transmits and receives the same radio wave from the plurality of antennas, and adjacent base stations share an antenna at a boundary. The mobile communication system according to claim 1 or 3, wherein an overlapping communication area is set according to (1). 8. A communication area is formed by one base station arranging a plurality of antennas on a line and transmitting and receiving the same radio wave from the plurality of antennas, and adjacent base stations communicate with one or more antennas. The communication area of the base station is overlapped by overlapping the area.
Or the mobile communication system according to 3. 9. A mobile communication system for communicating between a base station and a mobile station by continuously arranging base stations on a line and forming a series of communication areas on the line, wherein the base station comprises: Set overlapping communication areas between adjacent base stations, transmit pilot slots to mobile stations,
When a handover request is received from the mobile station, the mobile station performs a handover process.The mobile station communicates with the current base station, receives a pilot slot of the next base station, and performs a handover request based on the reception result of the pilot slot. Is transmitted to a next base station. 10. A mobile station communicating with a base station continuously arranged on a line, communicating with a current base station, receiving a pilot slot of a next base station, and receiving the pilot slot. A mobile station for transmitting a handover request to a next base station based on the mobile station.