JP2001267977A - Wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a conventional wireless communication system cannot continue communication with a base station when a mobile station moves from an area adopting an analog wireless system to an area adopting a digital wireless system. SOLUTION: Each of mobile stations 6, 7 mounts an analog receiver 14 and a digital receiver 15 that receive radio waves leaked from leakage coaxial cables LCX 3, 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system in which a mobile station traveling in both an analog radio area and a digital radio area communicates with a base station.

[0002]

2. Description of the Related Art For example, a conventional radio communication system in which a mobile station mounted on a Shinkansen vehicle communicates with a base station via a leaky coaxial cable (hereinafter referred to as LCX) employs only an analog radio system. Therefore, there is no case where both the area of the analog wireless system and the area of the digital wireless system exist, and there is no need to switch between the analog wireless system and the digital wireless system.

However, in an area where no LCX is installed, the mobile station and the base station cannot communicate with each other. Therefore, in such an area, a mobile phone (a mobile phone usually adopts a digital radio system) is used. A communication technique is disclosed in Japanese Patent Application Laid-Open No. 6-252833. Also,
In an area where an LCX is not installed, a technique is known in which a mobile station communicates using a protection radio (a protection radio usually adopts a digital radio system) for issuing a protection alert to another mobile station. It is disclosed in JP-A-11-285051. However, these technologies are wireless communication systems that enable communication in an area where LCX is not installed, and switching between an analog wireless method and a digital wireless method in an area where LCX is installed is essentially essential. Is different.

[0004]

Since the conventional wireless communication system is configured as described above, when a mobile station moves from an analog wireless area to a digital wireless area, a base station or another mobile station is required. There is a problem that communication with the device cannot be continued.

[0005] The present invention has been made to solve the above-described problems. Even when a mobile station travels between an analog radio area and a digital radio area,
An object of the present invention is to obtain a wireless communication system capable of continuing communication with a base station.

[0006]

A radio communication system according to the present invention has an analog receiver and a digital receiver for receiving radio waves leaking from a leaky coaxial cable mounted on a mobile station.

[0007] In the wireless communication system according to the present invention, when the identification signal cannot be detected by the analog receiver,
The communication with a base station is performed using a digital transmitter and a digital receiver.

In the wireless communication system according to the present invention, when the identification signal cannot be detected by the digital receiver, communication with the base station is performed using the analog transmitter and the analog receiver.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a wireless communication system according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a base station adopting a digital wireless system, for example, a base station installed near Takasaki Station on the Joetsu Shinkansen. The station employs a digital radio system. Reference numeral 2 denotes a base station that uses an analog wireless system. For example, a base station installed near Naganaka Shinna Station on the Nagano Shinkansen uses the analog wireless system.

Reference numeral 3 denotes a leaky coaxial cable (hereinafter referred to as LCX) laid on both sides of the track on which the Shinkansen vehicle travels, and carries the transmission radio wave of the base station 1 or the transmission radio waves of the mobile stations 6 and 7. LCXs 5 laid on both sides of the running track and carrying the transmission radio waves of the base station 2 or the mobile stations 6 and 7 are areas where the mobile stations 6 and 7 switch radio systems (hereinafter referred to as zone boundaries). Yes, zone boundary 5 is an area of about 20 meters between the end of LCX3 and the end of LCX4. Reference numeral 6 denotes a mobile station mounted on a Shinkansen vehicle that moves from a digital wireless area to an analog wireless area, and 7 denotes a mobile station mounted on a Shinkansen vehicle that moves from an analog wireless area to a digital wireless area. is there.

FIG. 2 is a block diagram showing the inside of the mobile stations 6 and 7, in which 11 is an antenna, 12 is a duplexer, 1
3 is a distributor, 14 is an analog receiver for receiving radio waves leaking from LCX3 or LCX4, 15 is LCX3 or LX
A digital receiver for receiving radio waves leaking from the CX4,
16 is an analog transmitter, 17 is a digital transmitter, 18
Controls the changeover switch 19 to connect the digital transmitter 17 to the duplexer 12 when the detection of the pilot signal (identification signal) by the analog receiver 14 is disabled.
When the detection of the base station identification signal (identification signal) by the digital receiver 15 is disabled, the controller 19 controls the changeover switch 19 to connect the analog transmitter 16 to the duplexer 12. A changeover switch for connecting the digital transmitter 17 or the analog transmitter 16 to the duplexer 12 under the instruction.

Next, the operation will be described. First, the case where the mobile station 6 moves from the area of the digital wireless system to the area of the analog wireless system will be described. Mobile station 6
Since the digital receiver 15 and the analog receiver 14 are always connected to the antenna 11 via the branching filter 12 and the splitter 13, it is possible to receive the radio wave leaked from the LCX3 or LCX4. It is in.

Therefore, when the mobile station 6 exists in the area of the digital radio system, the digital receiver 15 and the analog receiver 14 of the mobile station 6 receive the transmission radio wave of the base station 1 adopting the digital radio system. Can be. However, since the analog receiver 14 employs the analog wireless system, it cannot demodulate even if it can receive the transmission radio wave of the base station 1.

On the other hand, since the digital receiver 15 employs a digital wireless system, it can receive and demodulate a radio wave transmitted from the base station 1. The control unit 18 of the mobile station 6 establishes frame synchronization with the base station 1 by detecting a base station identification signal included in the frame of the transmission radio wave,
By controlling the changeover switch 19, the digital transmitter 17 is connected to the duplexer 12. As a result, the mobile station 6 can perform bidirectional communication with the base station 1.

Thereafter, when the mobile station 6 moves to the area of the zone boundary 5, the digital receiver 15 cannot receive the transmission radio wave of the base station 1 adopting the digital radio system. This makes it impossible for the control unit 18 of the mobile station 6 to detect the base station identification signal included in the frame of the transmission radio wave of the base station 1 (see FIG. 3). Then, the switch 19 is controlled to connect the analog transmitter 16 to the duplexer 12.

At this time, the analog receiver 14 cannot receive the radio waves transmitted from the base stations 1 and 2, but when the mobile station 6 moves to the area of the analog radio system, the analog receiver 14 The control unit 18 of the mobile station 6 can detect a pilot signal (a signal identifying the base station) included in the transmission radio wave since the transmission radio wave of the base station 2 adopting the system can be received and demodulated. To establish synchronization with the base station 2. Thereby, the mobile station 6 can perform bidirectional communication with the base station 2.

Next, a case where the mobile station 7 moves from the area of the analog wireless system to the area of the digital wireless system will be described. The digital receiver 15 and the analog receiver 14 of the mobile station 7 always have the duplexer 12 and the distributor 13
Is connected to the antenna 11 through the LCX3
Or, it is in a state where radio waves leaking from the LCX 4 can be received.

Therefore, when the mobile station 7 is located in the area of the analog radio system, the digital receiver 15 and the analog receiver 14 of the mobile station 7 receive the transmission radio wave of the base station 2 adopting the analog radio system. Can be. However, since the digital receiver 15 employs a digital wireless system, it cannot demodulate even if it can receive the transmission radio wave of the base station 2.

On the other hand, since the analog receiver 14 employs an analog wireless system, it can receive and demodulate a radio wave transmitted from the base station 2. The control unit 18 of the mobile station 7 establishes synchronization with the base station 2 by detecting a pilot signal included in the transmission radio wave, controls the changeover switch 19, and connects the analog transmitter 16 with the duplexer 12. Connecting. As a result, the mobile station 7 can perform bidirectional communication with the base station 2.

Thereafter, when the mobile station 7 moves to the area of the zone boundary 5, the analog receiver 14 cannot receive the radio wave transmitted from the base station 2 adopting the analog radio system. This makes it impossible for the control unit 18 of the mobile station 7 to detect the pilot signal included in the transmission radio wave of the base station 2 (see FIG. 4). By controlling 19, the digital transmitter 17 is connected to the duplexer 12.

At this time, the digital receiver 15 cannot receive the radio waves transmitted from the base stations 1 and 2, but when the mobile station 7 moves to the area of the digital radio system, the digital receiver 15 starts to operate. The control unit 18 of the mobile station 7 can detect and demodulate the base station identification signal included in the frame of the base station by transmitting and demodulating the transmission radio wave of the base station 1 adopting the system. 1 is established. As a result, the mobile station 7 can perform bidirectional communication with the base station 1.

As is apparent from the above, the first embodiment
According to the above, the analog receiver 14 and the digital receiver 15 for receiving radio waves leaking from the LCXs 3 and 4 are connected to the mobile stations 6 and 6.
7, the communication with the base stations 1 and 2 can be continued even if the mobile stations 6 and 7 run across the area of the analog wireless system and the area of the digital wireless system. To play.

[0023]

As described above, according to the present invention, an analog receiver and a digital receiver for receiving radio waves leaking from a leaky coaxial cable are configured to be mounted on a mobile station. There is an effect that communication with the base station can be continued even when the vehicle travels between the system area and the digital wireless area.

According to the present invention, when the identification signal cannot be detected by the analog receiver, communication with the base station is performed using the digital transmitter and the digital receiver. Can be promptly switched from the analog wireless system to the digital wireless system.

According to the present invention, when the identification signal cannot be detected by the digital receiver, communication with the base station is performed using the analog transmitter and the analog receiver. Can be quickly switched from the digital wireless system to the analog wireless system.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram showing the inside of a mobile station.

FIG. 3 is an explanatory diagram showing switching of a wireless system.

FIG. 4 is an explanatory diagram showing switching of a wireless system.

[Explanation of symbols]

1 base station, 2 base stations, 3 LCX (leakage coaxial cable), 4 LCX (leakage coaxial cable), 5 zone boundaries, 6 mobile stations, 7 mobile stations, 11 antennas, 12
Demultiplexer, 13 distributor, 14 analog receiver, 15
Digital receiver, 16 analog transmitter, 17 digital transmitter, 18 control unit, 19 changeover switch.

Continued on the front page (72) Inventor Yoshio Oshima 2-2-2 Yoyogi, Shibuya-ku, Tokyo East Japan Railway Company (72) Inventor Makoto Asazawa 2-6-1 Yoyogi, Shibuya-ku, Tokyo East F-term (reference) in Tokyo Electric Construction Office of Japan Railway Company 5K012 AA05 AB06 AB17 AB18 AC05 AC08 AC10 AC13 BA07 BA10 5K067 AA34 AA44 BB05 DD19 DD25 EE02 EE10 EE23 EE44 HH24

Claims (3)

[Claims] 1. A base station adopting an analog wireless system or a digital wireless system, a leaky coaxial cable laid beside a track and carrying a radio wave transmitted from the base station, and a radio wave leaking from the leaky coaxial cable. A wireless communication system including a mobile station having an analog receiver and a digital receiver for receiving. 2. The radio station according to claim 1, wherein when the detection of the identification signal by the analog receiver is disabled, the mobile station communicates with the base station using the digital transmitter and the digital receiver. Communications system. 3. The radio station according to claim 1, wherein the mobile station communicates with the base station using the analog transmitter and the analog receiver when the digital receiver cannot detect the identification signal. Communications system.