JP2005236554A - Radio relay equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of radio relay equipment being arranged in the dead area of a mobile communication system. <P>SOLUTION: The radio relay equipment comprises a downlink receiving antenna 3d principally receiving radio waves of downlink band from the radio base station 2 of a mobile communication system, a downlink band-filter 4d passing the downlink band of received signals selectively, a downlink amplifier 5d for amplifying the passed signals, a downlink transmission antenna 7d for transmitting the radio wave of amplified signal to a mobile station 6, an uplink receiving antenna 7u principally receiving radio waves of uplink band from the mobile station 6, an uplink band-filter 4u passing the uplink band of received signals selectively, an uplink amplifier 5u for amplifying the passed signals, and an uplink transmission antenna 3u for transmitting the radio wave of amplified signal to the radio base station 2. Signals of a partner line are attenuated by utilizing isolation between the antennas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radio relay apparatus arranged in a non-sensing area of a mobile communication system, and relates to a radio relay apparatus that reduces costs.

  With the widespread use of mobile phones, the places where users use mobile phones are not limited to urban areas, but are expanding to areas other than urban areas. Radio base stations have inevitably been installed in new areas in order to expand the service area in response to this increase in demand. On the other hand, there are many non-sensing areas (non-sensing zones) where radio waves do not reach, such as in buildings and subways, in areas already considered as service areas.

  Since the width of the non-sensing area is several tens of meters to several hundreds of meters, it is very disadvantageous in terms of cost to install a new radio base station in these non-sensing areas. In view of this, a wireless relay device has been considered for securing services to such an area.

  As shown in FIG. 5, the wireless relay device 51 of the background art includes a base station antenna 52, a base station antenna duplexer 53, a downlink amplifier 54, a mobile station antenna 55, and a mobile station antenna common use. 56 and an upstream amplifier 57. Each of the antenna duplexers 53 and 56 has a built-in band filter for separating the upstream signal and the downstream signal. The band-pass filter is composed of a resonator.

  For example, if the inside of the building is a non-detection area from the radio base station, the base station antenna 52 is installed outside the building, and the mobile station antenna 55 is installed inside the building.

  The downlink signal from the radio base station 2 is received by the antenna 52 for the base station, and the received signal is amplified by the downlink amplifier 54 via the antenna duplexer 53 for the base station, and then the mobile station via the antenna duplexer 56 for the mobile station. It is transmitted from the target antenna 55 as a downlink signal. The mobile station 6 receives this downlink signal.

  Further, the uplink signal from the mobile station 6 is received by the mobile station antenna 55, and the received signal is amplified by the uplink amplifier 57 via the mobile station antenna duplexer 56, and then passed through the base station antenna duplexer 53. It is transmitted from the station-oriented antenna 52 as an uplink signal. The radio base station 2 receives this uplink signal.

  In this way, by interposing the wireless repeater 51, a line can be secured between the mobile station 6 and the wireless base station 2 even in a building that is a non-sensing area.

JP-A-10-135900

  Here, the conditions under which the wireless repeater of FIG. 5 operates stably will be considered.

  As basic elements, assuming that the gain of the downstream amplifier 54 is A (dB; hereinafter abbreviated as a unit) and the gain of the upstream amplifier 57 is A, the loop gain of the wireless relay device 51 is 2 × A. In this wireless relay device 51, in order to amplify the downstream amplifier 54 or the upstream amplifier 57 without oscillating, it is necessary to attenuate the signal in the counterpart band by 2 × A or more. That is, the condition for the stable operation of the wireless repeater 51 of FIG. 5 is that the attenuation is 2 × A or more.

  FIG. 6 shows an example of gain distribution for uplink signals. In this figure, the band filter built in the antenna duplexer for base stations and the antenna duplexer for mobile stations is shown. That is, on the downlink side of the antenna duplexer for the base station, a band filter 61 for cutting a loop signal from the uplink is provided, and this band filter 61 has a gain of −A ( A attenuation amount). A similar band filter 62 is also provided on the downlink side of the antenna duplexer for mobile stations. On the other hand, on the uplink side of each antenna duplexer, band filters 63 and 64 are provided for cutting off wraparound signals from the downlink, respectively, and these band filters 63 and 64 are provided for uplink signals. The gain is 0 (dB).

  Contrary to the above, for the downlink signal, the band filters 63 and 64 each have a gain of −A, and the band filters 61 and 62 have a gain of 0 (dB).

  Thus, when the amount of signal wrapping from the uplink to the downlink or the downlink to the uplink in the antenna duplexer for the base station and the antenna duplexer for the mobile station is 0 (dB), the bandwidth of each antenna duplexer It is required that the gains in the cutoff regions of the filters 61, 62, 63, and 64 are -A or less (attenuation amount is A or more). In other words, each band filter is required to have an attenuation that exceeds the amplification factor of the amplifier in absolute value with respect to the signal in the other band.

  In addition, when a strong signal from another office (telephone service company) is input to the wireless relay device, the call is interrupted due to the interference caused by these signals, so the frequency of the other office exists. It is also required to block the adjacent frequency band.

  However, in order to increase the attenuation, the size of the resonator must be increased. Therefore, in order to realize a bandpass filter that satisfies the above requirements, the size of the resonator increases, and accordingly, the entire wireless relay device The cost of

  Therefore, an object of the present invention is to provide a wireless relay device that solves the above-described problems and reduces costs.

  In order to achieve the above object, the present invention provides a downlink receiving antenna that mainly receives downlink radio waves from a radio base station of a mobile communication system, and a downlink band filter that selectively passes the downlink band among the received signals. A downlink amplifier that amplifies the passing signal, a downlink transmitting antenna that transmits a radio wave based on the amplified signal to the mobile station, an uplink receiving antenna that mainly receives an uplink radio wave from the mobile station, and the received signal An upstream band filter that selectively passes an upstream band, an upstream amplifier that amplifies the passing signal, and an upstream transmission antenna that transmits a radio wave based on the amplified signal to a radio base station are provided.

  Attenuation amount for radio wave from the uplink transmission antenna in the downlink reception antenna, attenuation amount for reception signal in the uplink band in the downlink band filter, amplification amount in the downlink amplifier, and downlink transmission in the uplink reception antenna The amount of attenuation for the radio wave from the antenna, the amount of attenuation for the received signal in the upstream band in the upstream band filter, and the amount of amplification in the upstream amplifier are offset, or the sum of the amounts of attenuation is greater than the sum of the amounts of amplification. It can be large.

  In the downlink reception antenna and the uplink transmission antenna, electric field directions of radio waves to be transmitted and received may be orthogonal to each other.

  In the uplink reception antenna and the downlink transmission antenna, the electric field directions of radio waves to be transmitted and received may be orthogonal to each other.

  When the signal from each amplifier exceeds a predetermined level between the downlink amplifier and the downlink transmission antenna and between the uplink amplifier and the uplink transmission antenna, the signal is activated and supplied to each transmission antenna. An attenuator may be provided that reduces the signal to be below a predetermined level.

  The present invention exhibits the following excellent effects.

  (1) Cost can be reduced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  A radio relay apparatus 1 according to the present invention shown in FIG. 1 is installed in a non-sensing area in order to relay and amplify a radio wave having a channel frequency assigned to a base station 2 of a mobile communication system.

  The radio relay apparatus 1 includes a downlink receiving antenna 3d that mainly receives a downlink band radio wave Ed from the base station 2, a downlink band filter 4d that selectively passes the downlink band of the received signal, and the passing signal. A downstream amplifier 5d for amplification, a downstream transmission antenna 7d for transmitting a radio wave Ed based on the amplified signal to the mobile station 6, an upstream reception antenna 7u for mainly receiving an upstream band radio wave Eu from the mobile station 6, and the received signal Among them, an upstream band filter 4 u that selectively passes the upstream band, an upstream amplifier 5 u that amplifies the passing signal, and an upstream transmission antenna 3 u that transmits the radio wave Eu by the amplified signal to the base station 2 are provided. .

  As an example, the upstream band is 1429 to 1439 MHz, and the downstream band is 1477 to 1487 MHz. The upstream bandwidth of other offices is 1433 to 1453 MHz, and the downstream bandwidth is 1491 to 1501 MHz. The gain of the upstream amplifier 5u and the downstream amplifier 5d is 60 dB. The width of the non-sensing area is assumed to be several tens of meters.

  Compared with the radio relay apparatus of the background art (FIG. 5), the base station antenna 3 corresponding to the base station antenna 52 is divided into a downlink reception antenna 3d and an uplink transmission antenna 3u, which correspond to the mobile station antenna 55. The mobile station antenna 7 is divided into a downlink transmission antenna 7d and an uplink reception antenna 7u, and the base station antenna duplexer 53 and the mobile station antenna duplexer 56 are abolished. As a result, the uplink side and the downlink side are independent from each other.

  Between the downlink receiving antenna 3d and the uplink transmitting antenna 3u and between the downlink transmitting antenna 7d and the uplink receiving antenna 7u, a configuration is adopted in which the amount of spatial coupling between the antennas is small. Specifically, the base station antenna 3 and the mobile station antenna 7 each have a polarization diversity configuration. That is, the downlink reception antenna 3d and the uplink transmission antenna 3u have the electric field directions of radio waves to be transmitted and received intersect at 90 °. Further, the upstream receiving antenna 7u and the downstream transmitting antenna 7d intersect each other at 90 ° in the electric field direction of radio waves to be transmitted and received. As a result, between the downlink reception antenna 3d and the uplink transmission antenna 3u and between the downlink transmission antenna 7d and the uplink reception antenna 7u, the isolation between the two polarized waves transmitted and received by each antenna is 20 dB or more. Therefore, the attenuation amount for the radio wave from the uplink transmission antenna 3u in the downlink reception antenna 3d is 20 dB or more, and the attenuation amount for the radio wave from the downlink transmission antenna 7d in the uplink reception antenna 7u is 20 dB or more. Thereby, the downlink receiving antenna 3d mainly receives the downlink band radio wave Ed from the base station 2, and receives the radio wave Eu from the uplink transmission antenna 3u only slightly. The uplink receiving antenna 7u mainly receives the uplink band radio wave Eu from the mobile station 6, and receives only a small amount of radio wave from the downlink transmission antenna 7d.

  FIG. 2 shows gain distribution for the uplink signal of the wireless relay device 1.

  As shown in the figure, the attenuation amount of the radio wave from the uplink transmission antenna 3u in the downlink reception antenna 3d is 20 dB (gain is -20 dB), and the attenuation amount of the reception signal in the uplink band in the downlink band filter 4d is 80 dB (gain is- 80 dB), the amount of amplification in the downstream amplifier 5 d is 60 dB, the amount of attenuation of the radio wave from the downstream transmitting antenna 7 d in the upstream receiving antenna 7 u is 20 dB (gain is −20 dB), and the upstream band filter 4 u attenuates the upstream band received signal. The amount is 0 dB, and the amount of amplification in the upstream amplifier 5 u is 60 dB.

  The loop gain by the downstream amplifier 5d and the upstream amplifier 5u is 120 dB. Therefore, in order to amplify the downlink amplifier 5d or the uplink amplifier 5u without oscillating in the radio relay apparatus 1, it is necessary to attenuate the uplink signal by 120 dB or more. That is, it is only necessary that the amount of amplification and the amount of attenuation are offset or the amount of attenuation is larger.

  In the present invention, in the base station antenna 3 and the mobile station antenna 7, the amount of signal wraparound to the partner line is -20 dB. Therefore, the remaining −80 dB may be allocated to the downstream band filter 4d. In the background art, when the gain of the upstream and downstream amplifiers is 2 × A, two band-pass filters having an attenuation amount A are required for one side line. Therefore, if A = 60, a band filter for 120 dB in total is required. In the present invention, since it is sufficient if there is a band filter for 80 dB, the size of the resonator can be reduced by 40 dB. As a result, the cost of the wireless relay device 1 can be reduced.

  Since the downlink signal gain distribution has the same concept as the uplink signal gain distribution just described, the present invention can also reduce the size of the resonator by 40 dB.

  As a result, since the size of the resonator can be reduced, the cost of the wireless relay device 1 can be reduced.

  FIG. 3 shows a detailed circuit for the downlink in the wireless relay device 1 of FIG.

  The downlink includes a downlink band filter 4d that selectively passes a downlink band of signals from the input terminal in, a downlink amplifier 5d that amplifies the passing signal, and a variable attenuator 31 that attenuates the amplified signal at a desired ratio. A power amplifier 32 that drives the transmission antenna, a power branch device 33 that takes out the output level of the power amplifier 32 and controls the variable attenuator 31, and removes high-frequency components from the output of the power amplifier 32 to the output terminal out. And a low-pass filter 34 for output. Needless to say, the input terminal in is connected to the downlink receiving antenna, and the output terminal out is connected to the downlink transmitting antenna.

  In the received signal from the input terminal in, the downstream band filter 4d removes components other than the downstream band (upband components, components from other offices, etc.) smaller than −80 dB. The passing signal passes through the variable attenuator 31, is amplified by the power amplifier 32, passes through the power branching device 33, and is supplied from the output terminal out to the downlink transmitting antenna.

  In the power branching device 33, if the signal level is within a preset level, the variable attenuator 31 is not attenuated. If the signal level is equal to or higher than a preset level, attenuation is performed by the variable attenuator 31 and the signal level is adjusted to a preset level. Therefore, the gain distribution defined in FIG. 2 is not disturbed and the amplification amount does not exceed the attenuation amount.

  Since the low-pass filter 34 cuts off harmonic noise generated in the downstream amplifier 5d and the power amplifier 32, the spurious characteristics are improved.

  Needless to say, the configuration of the uplink is the same as that shown in FIG.

  FIG. 4 shows the characteristics of the downlink band filter 4d of the wireless relay device 1 of FIG. The horizontal axis represents frequency (GHz), and the vertical axis represents gain (dB). The numerical values of each axis at the main points m1 to m5 are appended. In the downstream band 1477 to 1487 MHz of the wireless relay device 1, a pass characteristic of almost 0 dB is obtained. On the other hand, in the uplink band 1429 to 1439 MHz of the wireless relay device 1, a cutoff characteristic with a gain of −80 dB or less is obtained. In addition, an attenuation amount with a gain of −15 or less is ensured even in the band of another office adjacent to the pass band.

  It goes without saying that the upstream band filter 4u also realizes the upstream band pass characteristic, the downstream band cutoff characteristic, and the appropriate attenuation characteristic of the band of another office.

  In the above embodiment, the downlink reception antenna 3d and the uplink transmission antenna 3u, and the uplink reception antenna 7u and the downlink transmission antenna 7d have the polarization diversity configuration so that the electric field directions of the radio waves to be transmitted and received intersect each other at 90 °. Although implemented, the present invention is not limited to this. For example, the direction in which the downlink receiving antenna 3d has the maximum gain and the direction in which the uplink transmitting antenna 3u has the maximum gain are set in the same direction, and the installation interval of both antennas is set to be equal to or larger than the use wavelength, thereby reducing the signal wraparound amount to 20 dB or less It is sufficient to secure the isolation by attenuation.

It is a block block diagram of the radio relay apparatus which shows one Embodiment of this invention. FIG. 2 is a gain distribution diagram for uplink signals of the wireless relay device of FIG. 1. FIG. 2 is a detailed block configuration diagram inside the wireless relay device of FIG. 1. FIG. 2 is a frequency versus gain characteristic diagram of a downstream band filter of the wireless relay device of FIG. 1. It is a block block diagram of the radio relay apparatus of background art. It is a gain allocation figure about the uplink signal of the radio relay apparatus of background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio relay apparatus 2 (Radio) Base station 3 Base station antenna 3d Downlink reception antenna 3u Uplink transmission antenna 4d Downband filter 4u Upband filter 5d Downlink amplifier 5u Uplink amplifier 6 Mobile station 7 Mobile station antenna 7d Downlink transmission antenna 7u Uplink receiving antenna

Claims (5)

  A downlink receiving antenna that mainly receives downlink radio waves from a radio base station of a mobile communication system, a downlink filter that selectively passes the downlink band of the received signal, and a downlink amplifier that amplifies the passing signal; A downlink transmission antenna that transmits radio waves based on the amplified signal to the mobile station, an uplink reception antenna that mainly receives uplink radio waves from the mobile station, and an upstream band filter that selectively passes the upstream band of the received signals And an uplink amplifier that amplifies the passing signal and an uplink transmission antenna that transmits a radio wave based on the amplified signal to the radio base station.   Attenuation amount for radio wave from the uplink transmission antenna in the downlink reception antenna, attenuation amount for reception signal in the uplink band in the downlink band filter, amplification amount in the downlink amplifier, and downlink transmission in the uplink reception antenna The amount of attenuation for the radio wave from the antenna, the amount of attenuation for the received signal in the upstream band in the upstream band filter, and the amount of amplification in the upstream amplifier are offset, or the sum of the amounts of attenuation is greater than the sum of the amounts of amplification. The wireless relay device according to claim 1, wherein the wireless relay device is large.   The radio relay apparatus according to claim 1 or 2, wherein the downlink reception antenna and the uplink transmission antenna have electric field directions of radio waves transmitted and received orthogonal to each other.   The radio relay apparatus according to any one of claims 1 to 3, wherein the uplink receiving antenna and the downlink transmitting antenna have electric field directions of radio waves transmitted and received orthogonal to each other. When the signal from each amplifier exceeds a predetermined level between the downlink amplifier and the downlink transmission antenna and between the uplink amplifier and the uplink transmission antenna, the signal is activated and supplied to each transmission antenna. The wireless relay device according to claim 1, further comprising an attenuator that reduces a signal to a predetermined level or less.

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