JPH0644729B2 - Diversity reception system using leaky coaxial cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a leaky coaxial cable,
Hereinafter referred to as LCX. The present invention relates to a diversity reception system using a leaky coaxial cable for obtaining a high-quality line for a standing wave due to radio wave interference caused by reception from the same frequency at a plurality of places in train wireless mobile communication using (1).

[Prior Art] For example, in mobile communication that uses individual communication such as public telephones, radio waves of the same frequency cannot be used simultaneously in the same area. For this reason, it is necessary to block (prohibit) the radio wave of the frequency being used so as not to be used by another mobile body.

Further, in a mobile communication system such as a train radio in which the moving direction and speed of the moving body can be predicted, the front and rear zones in which the moving body exists are blocked, and radio waves of the same frequency used at a remote place are transmitted to the moving body. It is necessary to secure the call time by avoiding collisions with each other. Explaining in a specific example, when the up and down mobiles approach each other, the call time = the distance of the closed section / (the speed of the up mobiles + the speed of the down mobiles) When a fast moving body catches up with, the call time is the distance of the blocked section / (speed of the fast moving body-speed of the slow moving body).

In such a mobile communication system, when one base station zone is wide, the base stations in communication with the respective mobile bodies associated with the movement of a plurality of mobile bodies using the same frequency are between base stations. Since it is necessary to maintain a distance that does not cause interference such as interference due to mutual reception of transmitted waves, it is difficult to repeat the same frequency and the efficiency of reusing the same frequency radio wave is poor. Therefore, it is necessary to increase the efficiency of reusing the same battery by limiting the range of the base station zone to an appropriate size.
The distance of one base station zone is determined by the traveling speed of the train and the call guarantee time, and the transmission frequency from the train is repeatedly used. Therefore, the base stations are arranged so as to secure the time for the train to travel in one base station zone. Has been decided. If the call guarantee time is secured, the shorter the base station zone, the higher the frequency utilization efficiency. Generally, in order to reduce the number of base station installation locations or for ease of maintenance, each station is extended in the train's uplink direction. Two base stations, which are base stations connected to the LCX, are installed.

FIG. 2 is a conceptual diagram of a conventional train radio system (Joetsu Shinkansen train radio system). Two base stations 1 are shown in FIG.
And 2 are arranged adjacent to each other, and the up line LCX and down line LCX of the train are connected to the base stations 1 and 2, respectively. In this way, two lines of LCX are laid and used as a backup line in the event of a failure, and on the train side, the reception input from the up line LCX and down line LCX is used as diversity reception.

In FIG. 2, (1) and (1 ') are transmission / reception duplexers, and (2) and (2') are transmission waves distributed to two LCXs (leakage coaxial cables).
A distributor for synthesizing received waves from the LCX, (3) and (3 ') are receivers, (5) and (5') are transmitters, and (6) and (6 ') communicate with mobile stations by radio waves. For the up and down lines LCX. Then, the transmission / reception demultiplexer (1), the distributor (2), the receiver (3)
And the transmitter (5) make up the base station 1 on the up side, while
The down side base station 2 is constituted by the transmission / reception branching filter (1 '), the distributor (2'), the receiver (3 ') and the transmitter (5'), and these base stations 1 and 2 are in the same area. It is installed in.

Here, the base station 1 on the up side refers to the control station side (not shown) when viewed from the base station 1, and the base station 2 on the down side refers to the anti-control station side when viewed from the base station 2. And This control station shares and manages an area called a large zone, and communicates with mobiles existing in the large zone via a plurality of base stations. Further, each of the plurality of control stations is connected to a central station (not shown) to monitor and control the corner control station.

Next, the operation will be described. Now, when there is a moving body on the side of the base station 1 on the up side, the radio waves transmitted from this moving body are received by the two-line LCX (6) of the up line and the down line,
After being combined by the distributor (2) via these LCX (6), the reception wave separated from the transmission wave by the transmission and reception demultiplexer (1) is guided to the receiver (3) and demodulated to output. .

At this time, the receiver (3 ') blocked for tracking is not used for the base station (base station 2 on the down side) in which no moving body exists. The received high frequencies picked up from the upstream and downstream lines LCX (6) and (6 ') are combined by the distributor (2).

[Problems to be Solved by the Invention] However, the conventional receiving method using the LCX is configured as shown in FIG. 2, and, for example, when the moving body exists on the up side, the moving body does not exist down. The base station 2 on the side of the up side is closed, and the high frequency waves received through the up and down lines LCX (6) and (6 ') are combined as they are by the distributor (2). Since the input level and phase of 2) were not adjusted, the combined output fluctuated greatly and a good-quality line could not be obtained.

Therefore, the present invention has been made in order to solve the conventional drawbacks, and is provided with a receiver which is connected to each of the two leaky coaxial cables and receives a radio wave from a moving body through the two leaky coaxial cables. By combining the demodulated outputs from these receivers with a combiner, a novel diversity reception system using a leaky coaxial cable that enables diversity reception is provided.

[Means for Solving the Problem] A diversity reception system using a simultaneous leakage table according to the present invention includes two leaky coaxial cables laid so as to extend in the same direction along a moving path of a moving body, and And a combiner for combining the demodulated outputs from these receivers, each of which is connected to each of the leaky coaxial cables described above, and which receives radio waves from the moving body via the leaky coaxial cables described in the above two articles. When the body is moving on the moving route, the radio wave from the moving body is transmitted to the above-mentioned 2
The input is made to the above-mentioned receiver through the leaky coaxial cable of the article.

[Operation] The diversity receiving system using the leaky coaxial cable according to the present invention enables the diversity reception in which receivers connected to the two leaky coaxial cables are provided and the demodulated outputs of these receivers are combined by the combiner. So you can get a good quality line.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, (10) and (11) are demultiplexers, which are connected to the down line LCX (12) and the up line LCX (13), respectively, and these L
It separates the transmission wave and the reception wave superimposed on the CX (12) and (13). (14), (15) are distributors for transmitted and received waves, (16)
Is a receiver and (17) is a transmitter. These duplexers (10), (1
1), demultiplexer (14), (15), receiver (16) and transmitter (17)
It constitutes the p-side base station 1. Similarly, the duplexer (18), (1
9), distributor (20), (21), receiver (22) and transmitter (23)
The base station 2 on the own side is configured, and the duplexers (18) and (19)
A down line LCX (24) and an up line (25) on the down side are connected to each. Thus, the base stations 1 and 2 are arranged adjacent to each other in the same area, and the demodulated outputs of the receiver (16) at the base station 1 and the receiver (22) at the base station 2 are input to the combiner (26). , This combiner (26) combines the demodulated outputs of these receivers (16) and (22), and selects the high input of the receiver (16) or (22) at an instant, so-called space diversity reception is configured. . And
For example, in FIG. 1, when a mobile exists on the up side and the mobile communicates with the base station 1, the base station 2 on the down side is controlled by a control station (not shown) so as to be blocked. The radio wave from the moving body on the up side is LCX
The receiver (16) of the base station 1 and the base station 2 via (12) and (13).
Any of the receivers (22) of the above can be received. The moving body
The same applies to the case where the mobile exists on the down side and the mobile body and the base station 2 communicate with each other.

Further, the operation will be described in detail. Now, when the mobile body is passing on the up side, the radio waves transmitted from the mobile body
It is coupled to CX (13) and downlink LCX (12) and guided to base station 1 and base station 2. Down line LCX on the up side (12)
The radio wave that has passed through is demultiplexed by the demultiplexer (10) in the base station 1, passes through the distributor (15), and is input to the receiver (16).
Radio waves from the upstream line LCX (13) pass through the demultiplexer (11) and are also input to the distributor (21) and the receiver (22) of the base station 2. At this time, the input from the up and down lines LCX (12), (13) is
Inputs to the two receivers (16) and (22) separately. This reception input is demodulated by these receivers (16) and (22) and then combined by a combiner (26). The receivers (16) and (22) control the combining ratio of the two received waves to combine them so that the noise output is minimized. The same applies when the moving body is passing on the down side. In this embodiment, the receivers (16) and (22) of the base stations 1 and 2 are configured to be shared, and a combiner (26) is added so that space diversity reception can be performed, so that the quality is good. A line can be provided.

[Effects of the Invention] As described above, according to the present invention, by adding a combiner, the radio waves respectively received by the two LCXs can be subjected to space diversity reception by the demodulated output of the receiver. Can provide a good line.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a conventional conceptual diagram. In the figure, (10), (11), (18) and (19) are duplexers, and (14) and (1
5), (20), (21) are distributors, (16), (22) are receivers, (26) are combiners, (17), (23) are transmitters, (12), (13), (twenty four),
(25) is a leaky coaxial cable. The same reference numerals in each drawing indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In mobile communication using a leaky coaxial cable, two leaky coaxial cables laid so as to extend in the same direction along a moving path of the mobile object, and two leaky coaxial cables, respectively. The mobile body moves along the movement route, which is provided with a receiver that is connected and receives radio waves from the mobile body via the leaky coaxial cable of the above-mentioned Article 2 and a combiner that synthesizes demodulated outputs from these receivers. A diversity receiving system using a leaky coaxial cable, characterized in that the radio wave from the moving body is input to the receiver via the leaky coaxial cable of the above Article 2 during the operation.