JPH0656977B2 - Wireless repeater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wireless relay device for relieving a weak electric field area in mobile communication.

(2) Conventional technology and its problems In a mobile communication system that divides a service area into multiple wireless zones, radio frequencies of different frequencies are used in adjacent wireless zones, and the same frequency is used again in zones spaced apart from each other without causing interference. The radio frequency of is used. This makes it possible to accommodate a large number of subscribers in a limited radio frequency band.

FIG. 1 is a diagram showing a wireless zone configuration. Reference numerals 1, 2, and 3 are wireless zones, and the entire service area is formed without a gap by forming a boundary portion with an overlapping configuration. The wireless base stations 11, 12, and 13 serve as service areas in the respective wireless zones. Radio frequencies of different frequencies are used in each radio zone, and radio frequency 21 in radio zone 1, radio frequency 22 in radio zone 2, radio zone 3
Uses radio frequency 23. 4 is a line control station,
5 is a mobile station. Since the service area is divided into a plurality of zones in this way, when the mobile station 5 moves between zones during a call, the communication channel is switched to connect the call.

The communication channel switching control procedure will be described. In the case of FIG. 1, the mobile station 5 is in the wireless zone 2 and is moving in the direction of the wireless zone 1. When the mobile station 5 crosses the zone boundary, the reception level of the radio frequency 22 from the mobile station 5 in the radio base station 12 decreases and falls below the specified value. The radio base station 12 notifies the line control station 4 of the decrease in the level of the radio frequency 22. The line control station 4 instructs surrounding radio base stations to monitor the level of the radio frequency 22, and each radio base station reports the reception level of the radio frequency 22 to the line control station 4. In the case of the figure, the radio frequency is
The reception level of 22 becomes the highest and the radio base station 12 receives the radio frequency being used with the mobile station 5 according to a command from the line control station 4.
22 is used to instruct the mobile station 5 to switch to the radio frequency 21. Further, the radio base station 11 sets the radio frequency 21, and the mobile station 5 switches to the radio frequency 21, whereby a new radio line is set up between the mobile station 5 and the radio base station 11, and the mobile station 5 makes a call. It is possible to continue.

On the other hand, in mobile communications, even in the service area, a weak electric field region in which radio waves from the radio base station are hard to reach occurs due to the influence of features such as tunnels. A wireless relay device (booster) for relieving a weak electric field area is used as a means for relieving a weak electric field area. FIG. 2 is an explanatory diagram of a weak electric field region and a conventional booster, in which a tunnel is used as a specific example. 6 is a tunnel, and the inside is a weak electric field area. A booster body 7 relays a vertical radio signal. Reference numeral 8 is a booster antenna for mobile stations, and 9 is an antenna for base stations.
Conventionally, a directional antenna has been used as the base station antenna 9, and the direction of the radio base station whose service area is the weak electric field area is the direction of the antenna. Therefore, in the case of FIG. 2, the transmission signal of the wireless base station 11 is transmitted in the order of [9 → 7 → 8] and is relayed inside the tunnel 6. Further, mobile station transmission signals inside the tunnel 6 are transmitted in the order of [8 → 7 → 9] and relayed to the radio base station 11. Therefore, even if the mobile station 5 uses the radio frequency 21 to enter the tunnel 6 during a call, the radio line between the mobile station 5 and the radio base station 11 is maintained and the call can be continued. is there.

However, when the conventional booster is used in a weak electric field area near the zone overlap area, inconvenience may occur, which situation will be described with reference to FIG. Tunnel 6 is in wireless zone 1, but one entrance is in the overlap of wireless zones 1 and 2 and the other entrance is not included in wireless zone 2. In such a case, the mobile station 5 is in the radio zone 1 and uses the radio frequency 21 to make a tunnel 6 during a call.
The call continues as described above even if the call comes in or goes out. Moreover, the mobile station 5 is in the radio zone 2 and the radio frequency
When entering inside the tunnel 6 during a call using 22,
Until the mobile station 5 reaches the entrance of the tunnel 6, the reception signal level of the radio frequency 22 in the radio base station 12 is equal to or higher than a specified value, and good communication is performed. When the mobile station 5 enters the inside of the tunnel 6, the antenna and 9 have no directivity in the direction of the radio base station 12, so the radio waves inside the tunnel 6 are not relayed in the direction of the radio base station 12 and In the station 12, the received signal level of the radio frequency 22 falls below the specified value and the line control station 4 is notified of the decrease in the radio frequency 22 level. Since the uplink of the radio frequency 22 is relayed to the radio base station 11, the radio base station 11 becomes the base station of the maximum reception level of the radio frequency 22, and the mobile station 5 is set to the radio base by the call channel switching control procedure. A command signal is sent from station 12 to switch channel to radio frequency 21 using radio frequency 22. However, since the downlink from the radio frequency 12 to the radio frequency 22 is not relayed inside the tunnel 6, the mobile station 5 cannot receive the channel switching command signal and cannot continue the call. .

On the other hand, in order to compensate for the above-mentioned drawback, it is conceivable to use 9 as an omnidirectional antenna and relay all the wireless lines used by the surrounding wireless base stations. With this configuration, even when the mobile station 5 talking on the radio frequency 22 enters the tunnel 6, the radio line is relayed by the booster and the call can be continued. However, if the mobile station 5 making a call using the radio frequency 22 inside the tunnel 6 exits the exit of the tunnel 6, the radio frequency 22 is not relayed outside the tunnel 6, and the call continues. There is a drawback that it becomes impossible.

(3) Object of the invention An object of the present invention is to provide a channel to a weak electric field area using a booster when a mobile station in a call enters from a peripheral wireless zone other than a wireless zone having the weak electric field area as a service area. It is an object of the present invention to provide a wireless relay device that can solve the problem that the call cannot be continued without a successful switching.

(4) Configuration of the invention (4-1) Differences between the features of the invention and the prior art In order to achieve this object, the wireless relay device of the present invention is
The service area is divided into a plurality of wireless zones, and in the adjacent wireless zones of the plurality of wireless zones, wireless communication is performed with each mobile station using radio channels having different radio frequencies, When the received wave level of a base station or mobile station drops, the cellular mobile communication system that switches the channel and switches the base station that communicates, and the radio waves such as the shadow of the feature or the tunnel at the boundary part of the adjacent wireless zone. In order to relieve the weak electric field area where it is hard to reach, a base station antenna, an amplifier, and a mobile station antenna are provided, and after receiving and amplifying the radio wave transmitted by the base station, the base station antenna re-radiates to the weak electric field area. A radio relay device that receives and amplifies a transmission radio wave of a mobile station located in an electric field area and then re-radiates the radio wave to a base station, the antenna of the radio relay device for the base station. As an uplink uplink antenna that is received by the base station when transmitted from the mobile station and a downlink downlink antenna that is received by the mobile station when transmitted from the base station, respectively. The line antenna is configured to have directivity limited to the direction of the plurality of base stations arranged in the wireless zone including all of the weak electric field area, and the downlink antenna is at least in the weak electric field area. It is configured to have directivity that directs to a plurality of the base stations arranged in a wireless zone including a part.

The conventional base station antenna of the wireless relay device for relieving a weak electric field area is common to the upper and lower lines, and has directivity only in the direction of the radio base station including the weak electric field area in its own zone.

Hereinafter, examples of the present invention will be described in detail.

(4-2) Embodiment FIG. 4 is a configuration diagram showing an embodiment of the present invention. Where 30
Is an upper / lower line separator and is constituted by a circulator, a filter for separating transmission / reception frequencies, or the like. Reference numeral 31 denotes a downlink anti-base station antenna, which has directivity not only in the direction of the wireless base station 11 but also in the directions of the surrounding base stations. Reference numeral 32 is an uplink base station antenna, which has directivity in the direction of the radio base station 11.

With such a configuration, when the mobile station 5 moves toward the wireless zone 1 during a call using the radio frequency 22 for the wireless zone 2 and enters the tunnel 6 before the channel switching is completed, Radio frequency 22 transmitted by mobile station 5
The reverse link is relayed in the order of [8 → 7 → 30 → 32]. Therefore, since the uplink in the tunnel 6 is not relayed toward the radio base station 12,
The received electric field in the uplink of 22 drops to a level below the specified value, and the radio base station 12 reports the drop of the radio frequency 22 level to the line control station 4 and channel switching control is performed. Radio frequency 22
The reception level of is highest in the wireless base station 11,
A command signal is transmitted from 12 to the mobile station 5 using the downlink of the radio frequency 22 to switch the channel to the radio frequency 21.
This signal is relayed in the order of [31 → 30 → 7 → 8] because the antenna 31 has directivity in the direction of the radio base station 12, and the mobile station 5 can receive the channel switching command signal. The mobile station 5 switches the used channel from the radio frequency 22 to 21 and newly sets the line with the radio frequency 11,
It becomes possible to continue the call.

(5) Effects of the Invention As described above, according to the present invention, even when a mobile station enters a weak electric field area such as a tunnel while using a channel of a peripheral wireless zone, a base that services the weak electric field area There is an advantage that the channel can be surely switched to the wireless line used by the station and the call can be continued. Furthermore, since the wireless line used by the base station that services the weak electric field area is used, it is clear that the call continues even when the mobile station leaves the weak electric field area during a call.

That is, according to the present invention, in a wireless relay device for relieving a weak electric field area such as a tunnel, an antenna for a base station for each of the upper and lower links is provided, and the antenna for the up link is directed toward a base station that serves the weak electric field area. The downlink antenna has directivity only to the base stations in the surroundings. Therefore, even if a mobile station using a channel in the peripheral wireless zone enters the weak electric field area without completing the channel switching, the channel is surely connected to the wireless line used by the base station that services the entered weak electric field area. It can be switched.

The present invention relates to a wireless relay device for relieving a weak electric field in mobile communication with a small zone configuration, and is effective when used in a system such as a car telephone, ship communication, aviation communication and the like.

[Brief description of drawings]

1 is a wireless zone layout diagram, FIG. 2 is a schematic configuration diagram for explaining a weak electric field area and a conventional booster, FIG. 3 is a schematic diagram for explaining inconveniences that occur in the conventional booster, and FIG. 4 is an embodiment of the present invention. It is a schematic diagram for explaining. 1, 2, 3 ... Wireless zone, 4 ... Line control station, 5 ...
Mobile station, 6 ... Tunnel, 7 ... Booster body, 8 ...
Booster antenna for mobile station, 9 ... Base station antenna, 11, 12, 13 ... Radio base station, 21, 22, 23 ... Radio frequency, 30 ... Booster up / down line separator, 31 ... Downlink-to-base station antenna, 32 ... Uplink-to-base station antenna.

Claims (1)

[Claims] 1. A service area is divided into a plurality of wireless zones, and adjacent wireless zones of the plurality of wireless zones perform wireless communication with each mobile station by using wireless channels of different radio frequencies, and When the reception wave level of the base station or the mobile station is lowered due to the movement of the mobile station, the cellular mobile communication method is performed in which the channel is switched and the base station for communication is switched. Or, in order to relieve weak electric field areas such as tunnels where radio waves are hard to reach, antennas for base stations, amplifiers,
It is equipped with an antenna for a mobile station, receives and amplifies base station transmission radio waves, and then re-radiates to the weak electric field region, and similarly receives and amplifies the transmission radio waves of mobile stations located in the weak electric field region to the base station. A re-radiating radio relay device, wherein the radio relay device uses as an antenna for the base station an uplink antenna for an uplink received by the base station when transmitted from the mobile station and a transmission from the base station. Each mobile station is provided with a downlink antenna for downlinks received by the mobile station, and the uplink antenna is restricted to the direction of a plurality of the base stations arranged in the radio zone including all of the weak electric field area. The downlink antenna is configured to have directivity, and the downlink antenna is configured to direct to a plurality of the base stations arranged in a wireless zone including at least a part of the weak electric field area. A characteristic wireless relay device.