JP2000031880A - Wireless relay device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To increase a relay distance in a wireless relay device for measures against a blind spot in a mobile communication system so that wireless channels usable in other systems are not reduced as much as possible. A wireless relay device (2) includes a frequency conversion circuit (23).
26, a sufficient gain is obtained by making the input and output radio frequencies of the radio relay device different to extend the relay distance. In particular, by using a 1.5 GHz band wireless channel provided to a government designated city between a wireless base station and a relay device, a 800 MHz band service area can be significantly and economically expanded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio relay device installed in a mobile radio system to eliminate dead zones where radio waves do not reach.

[0002]

2. Description of the Related Art In an area where radio waves do not reach, that is, a blind spot occurs in an automobile telephone or a portable telephone system, a radio base station is newly installed, or a radio relay device for collectively amplifying a desired band is installed. Measures are taken to allow connection to the base station. Of these, a large amount of cost is required to newly add a wireless base station, and the latter wireless relay device has been used, especially when traffic is very limited in a tunnel or in an extremely limited area. In this relay device, a desired frequency band is collectively amplified and relayed.

[0003]

However, installing a new radio base station requires enormous costs. In addition, in a wireless relay device that amplifies a desired band at a time, there is a problem in that a sufficient gain cannot be obtained and a relay distance is limited to several kilometers due to coupling between transmitting and receiving antennas.
Further, since a part of the radio frequency used for the service by the mobile station in the blind spot is used as the radio frequency for relay, there is a problem that the radio channels usable in the service band are reduced.

[0004] It is an object of the present invention to provide a radio relay apparatus for a mobile radio system which can perform long-distance relay and can be installed regardless of traffic.

[0005]

In order to achieve the above object, the present invention provides a method for transmitting a signal in a radio band, which has been transmitted from a radio base station and is allocated to a downlink of a first radio band. Downlink frequency conversion means for converting to a signal in the wireless band allocated to the downlink of the second wireless band and transmitting the signal to the mobile station, and the second wireless band transmitted from the mobile station Uplink frequency conversion for converting a signal in a radio band assigned to the uplink of the first radio band into a signal in a radio band assigned to the uplink of the first radio band and transmitting the signal to the radio base station. Means, amplifying means for a downlink for amplifying the signal of the downlink on at least one of an input side and an output side of the frequency converting means for the downlink, and the frequency converting means for the uplink for the uplink signal To provide a radio relay apparatus characterized by comprising an amplifier means for uplink for amplifying at least one of the input or output side.

The present invention also provides a method for transmitting a signal in a radio band assigned to a downlink of a first radio band, which is transmitted from a radio base station, to a radio signal assigned to a downlink of a second radio band. Frequency conversion means for converting to a signal in the band and transmitting to the radio paging device, and amplification means for amplifying at least one of the input side or the output side of the frequency conversion means, Provided is a wireless relay device provided with:

[0007]

Embodiments of the present invention will be described below in detail. FIG. 1 is a block diagram illustrating a configuration example of a wireless relay device according to the present invention. A wireless relay device 2 according to the present invention is installed between a wireless base station 1 and a mobile station 3. The transmitter 10 and the receiver 11 of the radio base station 1 transmit and receive radio waves via the antenna 12. The radio wave of the radio frequency f1 downstream of the radio base station 1 is received by the antenna 20 of the radio relay device 2 facing the direction of the radio base station 1. Antenna 2
The radio wave received at 0 is amplified by the amplifier 22 via the antenna sharing device 21 and frequency-converted by the frequency conversion unit 23 to become the frequency f2. The radio frequency signal of this frequency f2 is amplified by the amplifier 24, passes through the antenna duplexer 28,
It is transmitted from the antenna 29. The mobile station 3 uses this frequency
By receiving the radio frequency signal of f2, it becomes possible to receive a mobile communication service in an area which was conventionally blind. On the other hand, the radio wave of the frequency F2 transmitted from the mobile station 3 is received by the antenna 29, sent to the amplifier 27 through the antenna duplexer 28, amplified there, and then converted into a signal of the frequency F1 by the frequency conversion unit 26. Is converted. Thereafter, the signal is amplified by the amplifier 25 and transmitted from the antenna 20 via the antenna sharing device 21. This radio wave of frequency F1
The signal is received by the receiver 11 via the antenna 12 of the wireless base station 1.

In the present invention, f1 and f2, which are downstream radio frequencies, are radio frequencies of different bands, and F1 and F2, which are upstream radio frequencies, are also radio frequencies of different bands. For this reason, it is not necessary to consider the oscillation margin due to the interference between the antennas 20 and 29, which has been a problem in the conventional wireless relay device in which f1 and f2 have the same frequency, and the amplifiers 22, 24, 25, and 27 need not be considered. The gain can be made sufficiently large. That is, long-distance relay becomes possible.

At present, there are 1.5
There are two types: GHz band type and 800MHz band type.
The z-band system is provided nationwide. In particular, there are many radio blind spots in rural areas, and it is desired to eliminate blind spots in order to expand service areas. It is economically difficult to install a new wireless base station in a rural area simply to eliminate the dead zone of the 800 MHz band system. In such an environment, the service area can be easily expanded by setting f2 and F2 to frequencies in the 800 MHz band and f1 and F1 to frequencies in the 1.5 GHz band according to the present invention. That is, the wireless relay device 2 is installed in the vicinity of the blind spot area, and the 1.5 GHz band frequency from the wireless base station 1 is relay-amplified. Therefore, the transmitter 10, the receiver 11, the antenna 12
Is a device in the 1.5 GHz band. In addition, the antenna 20, the amplifiers 22, 25 of the wireless relay apparatus 2 are 1.5 GHz band devices, the amplifiers 24, 27, and the antenna 29 are 800 MHz band devices.
The frequency of the band is converted to the frequency of the 800 MHz band.
Convert to frequency in Hz band. With such a system configuration, 1.5 GHz band devices have already been developed, and by using these existing devices, 800 MHz can be economically realized.
A wireless relay device capable of extending the service area of the z-band far more than before can be configured.

Here, it is necessary to pay attention to the frequency channel used between the relay device 2 and the base station 1. First, the frequency band of the 1.5 GHz band assigned to the downlink channel is directly converted, and the frequency is shifted by the frequency converting unit 23 to the band assigned to the 800 MHz downlink channel. , And a method of performing the reverse conversion. In this way, when converting the entire band by frequency shifting,
All channels in the 1.5 GHz band can be used.

However, in an environment where the antenna 20 of the radio relay apparatus 2 may receive a channel other than the 1.5 GHz band channel transmitted from the antenna 12 of the radio base station 1, the channel Will be converted to an 800 MHz band channel corresponding to. This is, for example, around the urban area, different from this system,
This is the case when the base station of the 1.5 GHz system exists nearby. In such a case, the base station 1 and the relay device 2
The channel of the 1.5 GHz band used in between is limited to a specific channel in advance. And the limited channel is
The channel may be a channel that is not used by a base station of another system in proximity.

Another solution in the case where there is an influence of another system in the 1.5 GHz band is to prevent a specific channel used in the present system from being used in those adjacent systems. In this case, the number of channels that can be used in other systems decreases, but this can relieve the dead zone.

FIG. 2 shows a case where the present invention is applied to a radio call system. In the figure, the radio calling device 6 has radio frequency f4.
Serviced by If there is a blind spot, the wireless relay device 5 is installed near the blind spot. The transmitter 40 and the antenna 4 of the frequency f3 are transmitted to the radio base station 1 originally transmitting at f4.
1 is transmitted, and a signal which has been called at the frequency f4 in the past is also transmitted at the frequency f3. The transmitted radio frequency signal of frequency f3 is received by the antenna 50, amplified by the amplifier 51, and converted into a signal of frequency f4 by the frequency conversion unit 52. The signal is amplified by the amplifier 53, transmitted from the antenna 54, and received by the paging device 6. f
By setting 3 and f4 to radio frequencies in different frequency bands, interference between antennas 50 and 54 is avoided, and amplifiers 51 and 5 are used.
3, a large amplification degree can be set, so that the service area of the wireless relay device 2 can be made larger than that of the conventional wireless relay device. In particular, f3 is a frequency in the 1.5 GHz band, f3
By setting 4 to the frequency of the 280 MHz band, it can be applied to the currently serviced paging system.
As described in detail in the description of FIG. 1, since the 1.5 GHz band device has been developed, an economical wireless relay device can be configured by using the 1.5 GHz band as f3.

[0014]

The present invention has the following advantages. (1) Since the input frequency and the output frequency of the relay device are different, a high gain is obtained and a long relay distance is obtained. (2) The service area can be expanded much more economically than installing a new wireless base station in a blind spot. Also, maintenance and operation costs are very economical. (3) By using the 1.5 GHz band for the trunk line, the frequency possessed by the carrier can be effectively used, and the already developed 1.5 GHz band device can be diverted, which is economical. . (4) Since the 1.5 GHz band has a relatively large radio channel margin, the radio frequency band is used for the relay line, so that the radio relay device can be used without affecting the band used by the mobile station. Can be installed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a wireless relay device according to the present invention.

FIG. 2 is a block diagram illustrating another configuration example of the wireless relay device according to the present invention.

[Description of Signs] 1 wireless base station 2 wireless relay apparatus 3 mobile station 4 paging wireless base station 5 paging wireless relay apparatus 6 wireless paging apparatus 10 transmitter 11 receiver 12 antenna for wireless relay apparatus 20 versus wireless base Station antenna 21: Antenna duplexer for radio base station 22, 24, 25, 27 Amplifier 23, 26 Frequency conversion unit 28: Antenna duplexer for mobile station 29: Antenna for mobile station 40: Radio paging transmitter 41 Antenna for wireless relay device 50 Antenna for wireless base station 51, 52 Amplifier 52 Wireless relay device 54 Antenna for wireless paging device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoichi Okubo 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Electric Co., Ltd. (72) Inventor Hiroshi Suzuki 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Electric F term in the company (reference) 5K067 AA11 AA22 BB02 CC02 EE02 EE06 EE10 EE22 5K072 AA29 BB12 BB13 CC13 CC32 DD11 DD16 FF22 GG01 GG22 GG39

Claims (5)

[Claims] 1. A signal in a wireless band assigned to a downlink of a first wireless band, which is transmitted from a wireless base station, and a signal in a wireless band assigned to a downlink of a second wireless band. Downlink frequency conversion means for converting to and transmitting to the mobile station, a signal in the radio band assigned to the uplink of the second radio band transmitted from the mobile station, the first Uplink frequency conversion means for converting to a signal in the wireless band allocated to the uplink of the wireless band and transmitting the signal to the wireless base station, and Amplifying means for a downlink for amplifying at least one of an input side and an output side; and amplifying the signal of the uplink for at least one of an input side and an output side of the frequency conversion means for an uplink. A wireless relay apparatus comprising: amplifying means for uplink. 2. The frequency conversion means for downlink and the frequency conversion means for uplink perform frequency conversion of only one or a plurality of predetermined frequency channels in the first and second radio bands. The wireless relay device according to claim 1, wherein 3. The wireless communication system according to claim 1, wherein the first wireless band is a wireless band of 1.5 GHz, and the second wireless band is a wireless band of 800 MHz. Relay device. 4. A signal in a radio band assigned to a downlink of a first radio band, which is transmitted from a radio base station, and a signal in a radio band assigned to a downlink of a second radio band. And amplifying means for amplifying at least one of the input side or the output side of the frequency conversion means, A wireless relay device characterized by the following. 5. The wireless communication system according to claim 4, wherein the first wireless band is a wireless band of 1.5 GHz band or 800 MHz band, and the second wireless band is a wireless band of 280 MHz band. Wireless relay device.