JPH11150502A - One-to-multi radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the one-to-multi radio communication system by processing local traffic in a base station while reducing the cost required for the base station so that exchange load of a central base station is relieved. SOLUTION: A radio signal sent from a transmitter side subscriber station 100 and received by a base station 200 is converted into a reception frequency band corresponding to a receiver side subscriber station 100 from the transmission frequency band without modification of the modulation signal, and the base station 200 sends the converted signal to the receiver side subscriber station 100 to allow the base station to conduct exchange processing while suppressing the cost required for the base station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a point-to-multipoint wireless communication system, and more particularly, to a system in which a plurality of subscriber stations have a predetermined transmission frequency band and reception frequency allocated to a microwave, quasi-millimeter wave, or millimeter wave band. The present invention relates to a one-to-many wireless communication system that wirelessly communicates with a base station using a band.

[0002]

2. Description of the Related Art The demand for a high-speed network has been increasing with the rapid spread of the Internet connection and the like in recent years. However, high-speed lines provided by wired networks are still expensive for ordinary consumers, and local wireless communication networks capable of providing lower-cost services are being actively researched and developed. . This local wireless network uses quasi-millimeter waves (3 GHz to 30 GHz).
z), and also in the millimeter wave band (30 GHz to 300 GHz)
Utilizing such a high frequency band, it is used, for example, to provide a high-speed two-way data communication line from a telephone exchange to a plurality of subscribers located in a predetermined area or to provide a local television service. Here, FIG. 7 shows an example of a functional block diagram of a point-to-multipoint wireless communication system used in LMDS and the like implemented in the United States.

As shown in FIG. 7, the above-described one-to-many wireless communication system includes a plurality of subscriber stations 100 each having a transmitting side.
An interface device 101 connected externally, a modulator 102, and a frequency converter 103 for converting a modulated signal output from the modulator 102 to an intermediate frequency for transmission.
A frequency converter 104 for converting an intermediate frequency signal output from the frequency converter 103 to a radio frequency for transmission, and a high-power solid-state amplifier for transmission for amplifying the radio signal output from the frequency converter 104 105,
It has a diplexer 106 and an antenna 107 for both transmission and reception. A low noise amplifier 108 for amplifying a radio signal received via the antenna 107 and the diplexer 106 is provided on the receiving side of each of the subscriber stations 100.
A frequency converter 109 for converting a signal output from the low-noise amplifier to an intermediate frequency for reception;
0 and a demodulation device 111.

On the other hand, a receiving antenna 201 and an antenna are provided on the receiving side of a base station 200 which is connected to the plurality of subscriber stations 100 by a radio line using a microwave, quasi-millimeter wave, or millimeter wave band. A low noise amplifier 202 for amplifying the radio signal supplied from the low noise amplifier 201;
2, a frequency converter 203 for converting the signal output from the receiver 2 into an intermediate frequency for reception, a distributor 204, and a subscriber station 1.
The tuner 205 includes a plurality of tuners 205 for tuning to 00 and selecting a reception intermediate frequency, a demodulation device 206 provided for each tuner 205, and an interface device 207 externally connected. Also, on the transmitting side of the base station 200, a plurality of modulators 208 for modulating the transmission data supplied from the interface device 207, and a frequency converter for converting a signal output from the modulator 208 to an intermediate frequency for transmission. A device 209, a synthesizer 210, a frequency converter 211 for converting a signal from the synthesizer 210 to a radio frequency for transmission, a transmission high-power solid-state amplifier 212 for amplifying an output of the frequency converter 211, Antenna 213.

In the above wireless communication system, on the uplink where a signal is transmitted from the subscriber station 100 to the base station 200, transmission data supplied from the outside is supplied to the modulation device 102 via the interface device 101. The transmission data is converted by the modulation device 102 into a modulation signal of a predetermined occupied frequency band. Modulation device 1
02 is output from the frequency converter 103
Is converted to an intermediate frequency for transmission, and further converted by the frequency converter 104 to a radio frequency for transmission.
The radio signal output from the frequency converter 104 is
After being amplified to a required transmission output level by the transmission high-output solid-state amplifier 105, it is supplied to the transmission / reception antenna 107 and transmitted to the base station 200. The communication wave RF-U transmitted from the antenna 107 of the subscriber station 100 is received by the receiving antenna 201 of the base station 200 and amplified by the low-noise amplifier 202 for reception.
03 is converted to an intermediate frequency for reception. The signal of the intermediate frequency for reception is distributed by the distributor 204 and supplied to the tuner 205 group. The reception intermediate frequency is selected by a tuner 205 tuned to the subscriber station 100 and supplied to demodulators 206 provided for the respective tuners 205. The modulated wave demodulated by the demodulator 206 returns to the original transmission data, is connected to an external network via the interface device 207, or becomes transmission data to another subscriber station 100.

On the downlink where signals are transmitted from the base station 200 to the subscriber station 100, first, transmission data from an external network or another subscriber station 100 is supplied to the modulation device 208 via the interface device 207. Is done. The modulator 208 converts the transmission data into a modulation signal of a predetermined occupied frequency band. Modulation device 2
08 is output from the frequency converter 209.
Is converted into an intermediate frequency for transmission, and the combiner 210 combines the signal with another intermediate frequency signal for transmission. The signal of the intermediate frequency synthesized by the synthesizer 210 is further converted to a radio frequency for transmission by a frequency converter 211 and amplified to a required transmission output level by a high-power solid-state amplifier 212 for transmission. And transmitted to the subscriber station 100. Communication wave RF-D transmitted from transmitting antenna 213 of base station 200
Is received by the transmission / reception antenna 107 of the subscriber station 100, and separated from the transmission signal by the diplexer 106. The reception signal output from the diplexer 106 is amplified by the reception low-noise amplifier 108, and is converted by the frequency conversion device 109 into a signal of the reception intermediate frequency. The tuner 110 selects the signal of the intermediate frequency for reception and supplies the signal to the demodulation device 111. Demodulator 111
The demodulated wave returns to the original data for transmission,
It is connected to an external network or the like via the interface device 101.

In the above-described radio communication system, as shown in FIG. 8, one base station 200 transmits / receives data to / from the subscriber station 100 due to the limitation of the communication capacity per frequency band and the limit of the radio wave reachability. A predetermined area is covered by overlapping a plurality of cells C to be performed. The base station 200 of each cell C is connected to the centralized base station 300 and has a configuration capable of communicating with each other. Base station 200 and centralized base station 300
In many cases, connection between the base station 200 and the centralized base station 300 is performed using one-to-one wireless communication for the purpose of reducing the installation cost of the optical fiber. . In this case, it is possible to provide a service even in an area relatively distant from the backbone, such as providing a service to a rural area. The communication between the base station 200 and the centralized base station 300 is almost the same as the communication between the subscriber station 100 and the base station 200 described above. In the above-described wireless communication system, path control is performed. The switch can be located at each base station 200 or at the centralized base station 300. For example, when a switch is installed in the base station 200 and communication is performed between a certain subscriber station 100 and another subscriber station 100 in the same base station 200, first, the transmission received by the base station 200 is performed. After the above-described frequency conversion, the radio signal from the side subscriber station 100 is demodulated to the original transmission data by the demodulation device 206 provided in the base station 200. Then, the header information is read from the digital signal demodulated and returned to the original transmission data by the above-mentioned exchanger, and the routing destination is set. Then, from the routed port, the modulator 2
08 and modulated. The modulated signal is converted to a specific frequency band corresponding to the subscriber station 100 on the receiving side, and then transmitted from the base station 200 to the subscriber station 100 on the receiving side.

[0008]

When performing the above-described switching processing, the base station or the centralized base station includes, in addition to the switch, a modulator, a demodulator, a converter to an intermediate frequency,
A tuner or the like is required. However, if an exchange requiring these modulators and demodulators is provided for each of a plurality of base stations provided in a predetermined area, the cost of the entire system becomes enormous. On the other hand, a technique in which a base station is not provided with a switch which requires a modulator, a demodulator, and the like, but is provided in a centralized base station is disclosed in, for example, Japanese Patent Laid-Open No.
No., etc. Here, FIG. 9 is a diagram showing a schematic configuration of the mobile communication system described in the above publication.

[0009] As shown in FIG. 9, in the mobile radio communication system described in the above publication, the base station 900 does not perform switching processing, and the switch 901 is provided only in the centralized base station 902. Also, a one-to-many first wireless link 904 connecting the mobile terminal 903 and the base station 900, and a one-to-one second wireless link 905 connecting the base station 900 and the centralized base station 902.
, Different frequency bands are used, and the base station 900 has a first wireless link 904 and a second wireless link 9.
A frequency conversion unit 906 that performs frequency conversion between the frequency conversion unit 05 and the frequency conversion unit 05 is provided. In the mobile radio communication system, for example, when transmission is performed from the mobile terminal 903a to another mobile terminal 903a belonging to the same base station 900, the base station 9
00, the switching process is not performed, and the signal from the transmitting mobile terminal 903a received by the base station 900 is converted by the frequency conversion unit 906 from the frequency band of the first wireless line 904 to the second wireless line 905. And then transmitted to the centralized base station 902.
In the centralized base station 902, the signal from the base station 900 is down-converted by the frequency converter 907,
The signal is demodulated by the modem 908. This modem 9
08 is connected to the exchange 901, and the modem 90
The demodulated signal output from 8 is supplied to the switch 901. Then, the routing destination is set based on the digital signal demodulated by the switch 901 and again the modem 9
08. Then, the signal modulated by the modulation / demodulation device 908 is up-converted by the frequency conversion device 907, and transmitted to the base station 90 via the second radio line 905.
Sent to 0. Then, in the base station 900,
The signal from the centralized base station 902 is converted to a frequency
Is converted into a frequency band to be used in the first wireless channel 904 and transmitted to the mobile terminal 903b. That is, in the mobile radio communication system, for example, even in the case of the mobile terminal 903 belonging to the same base station 900, the exchange processing is not performed by the base station 900 but all communication is performed via the centralized base station 902. , Base station 900 is suppressed from increasing.

However, since the switching load of the local traffic processed in the base station 900 is originally added to the centralized base station 902, the switching load of the centralized base station 902 is significantly increased in the mobile radio communication system. ,
If it is necessary to use an expensive exchanger 901 for high-speed processing, or if it is not enough, problems such as impairment of smooth operation may occur. Further, the wireless line 905 needs an extremely wide band line through which all signals can pass, and there is a problem that the system becomes a wasteful frequency band. SUMMARY OF THE INVENTION In order to solve the problems in the prior art, the present invention improves a point-to-multipoint wireless communication system and processes local traffic in the base station while reducing the cost required for the base station. It is an object of the present invention to provide a one-to-many wireless communication system with reduced switching load.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of subscriber stations are provided with a predetermined transmission frequency assigned to a microwave, quasi-millimeter wave, or millimeter wave band. In a one-to-many wireless communication system that wirelessly communicates with a base station using a band and a reception frequency band, a radio signal from the transmission side subscriber station received by the base station is converted from the transmission frequency band to the reception side subscriber as a modulated signal. The gist is that the signal is converted into a reception frequency band corresponding to the station and is transmitted from the base station to the receiving subscriber station. According to the first aspect of the present invention, even when communication is performed from an arbitrary subscriber station to another subscriber station via the base station, a radio signal from the transmitting subscriber station received by the base station is received. Since the signal is converted into a reception frequency band corresponding to the receiving subscriber station as it is as a modulated signal, the base station transmits a modulation device, a demodulation device,
There is no need to provide a frequency conversion device to an intermediate frequency, a tuner, and the like, and the cost of the base station and the entire system can be reduced.

According to a second aspect of the present invention, in the point-to-multipoint wireless communication system according to the first aspect, the transmission frequency band of the transmitting subscriber station and the receiving frequency band of the receiving subscriber station are different. The gist is that the frequency conversion amount between them is set in advance. According to the second aspect of the present invention, since the frequency conversion amount between the transmission frequency band of the transmitting side subscriber station and the receiving frequency band of the receiving side subscriber station is set in advance, any desired subscription is possible. Communication from a subscriber station to a specific subscriber station in the same base station can be performed without using an expensive switch, and the cost of the base station and the entire system can be reduced.

According to a third aspect of the present invention, in the point-to-multipoint wireless communication system according to the first aspect, the radio signal from the transmitting side subscriber station received by the base station is temporarily transmitted from a transmission frequency band. The gist is that the frequency is converted to an intermediate frequency band and the modulated signal is frequency-converted to a reception frequency band selected in the intermediate frequency band as it is. According to the third aspect of the present invention, the first aspect
As in the point-to-multipoint wireless communication system described in (1), the radio signal from the transmitting subscriber station received by the base station is temporarily converted to an intermediate frequency, and then converted from the intermediate frequency to a reception frequency band as a modulated signal. Since it is transmitted, there is no need to provide a modulator or demodulator in the base station, and
By selecting the receiving frequency band of the receiving subscriber station in the intermediate frequency band, it becomes possible to use an inexpensive matrix switch, and the cost of the base station and the entire system can be reduced. Further, by selecting the reception frequency band in the intermediate frequency band, the same frequency band can be routed to a plurality of subscriber stations, and the required frequency channels can be reduced.

According to a fourth aspect of the present invention, in the point-to-multipoint wireless communication system according to any one of the first to third aspects, the base station has a plurality of sectors using different frequency bands. And the radio signal from the transmitting subscriber station received by the base station is converted from a transmitting frequency band to a receiving frequency band allocated to the sector to which the receiving subscriber station belongs as a modulated signal. Is the gist. According to a fifth aspect of the present invention, in the point-to-multipoint wireless communication system according to the fourth aspect, the transmitting subscriber station and the receiving subscriber station belong to different sectors. . According to the fourth or fifth aspect of the present invention, the radio signal from the transmitting subscriber station is frequency-converted as a modulated signal to a receiving frequency band allocated to a sector to which the receiving subscriber station belongs. Therefore, even when the communication is performed between the subscriber stations belonging to the same sector or between the different sectors, the cost of the base station and the entire system can be reduced in the same manner as in the first or second aspect of the invention. .

According to a sixth aspect of the present invention, in the point-to-multipoint wireless communication system according to any one of the first to fifth aspects, information on a reception frequency band is transmitted from the base station to the subscriber station. The gist is that a signal is transmitted. According to the sixth aspect of the present invention, even when the allocation of the reception frequency band corresponding to each subscriber station is changed in the base station, it is possible to perform the correct channel selection in the subscriber station. .

According to a seventh aspect of the present invention, in the point-to-multipoint wireless communication system according to any one of the first to sixth aspects, the base station temporarily demodulates a received signal and sets a connection destination. The point is that it is connected via a point-to-point wireless line to a centralized base station having a switching function of transmitting the signal to the connection destination after modulating again. According to an eighth aspect of the present invention, in the point-to-multipoint wireless communication system according to the seventh aspect, the gist is that the base station is connected to another base station via the centralized base station. I do.
According to the invention described in claim 7 or 8, even when an arbitrary base station is connected to another base station or an external network via the centralized base station, an exchange load due to local traffic per base station is small. Since processing is performed in the base station, smooth operation can be achieved without excessive concentration on the centralized base station. In addition, it is possible to use a switch having a relatively low processing capacity for the exchange of the centralized base station, and it is possible to reduce the cost.

According to a ninth aspect of the present invention, in the point-to-multipoint wireless communication system according to the seventh or eighth aspect,
The gist is that a signal including information on a reception frequency band is transmitted from the centralized base station to the base station. According to the ninth aspect of the present invention, even when the allocation of the reception frequency band corresponding to each subscriber station is changed in the centralized base station, it is possible to perform the correct channel selection in the subscriber station. Become.

According to a tenth aspect of the present invention, in the point-to-multipoint wireless communication system according to any one of the seventh to ninth aspects, a connection request from one subscriber station to another subscriber station is: When the connection is made to the centralized base station via the base station, a communication path via an exchange of the centralized base station or a communication in which the modulated signal is transmitted and received within the base station, depending on the availability of the intermediate line. The gist of the present invention is to select whether to make a route by the centralized base station. According to the tenth aspect, a route is selected from the centralized base station according to the availability of the intermediate line, so that a limited frequency band can be effectively used.

[0019] According to an eleventh aspect of the present invention, in the point-to-multipoint wireless communication system according to any one of the seventh to tenth aspects, the centralized base station is installed inside a building, and The gist is that it was installed in a place with good visibility. According to the invention described in claim 11,
Since the base station is installed in a place with good visibility such as the top of a tower or the top of a mountain, the area covered by one base station can be expanded. It should be noted that the base station constituting the point-to-multipoint wireless communication system according to the present invention is heavy and large in power consumption.
Maintenance is required, and since there is no equipment such as a modulation device, a demodulation device, or an exchange that requires air conditioning inside, it can be easily installed in the above-described location.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The following embodiment is a specific example of the present invention and does not limit the technical scope of the present invention. As shown in FIG. 1, in a wireless communication system according to an embodiment of the present invention, a plurality of subscriber stations 100 are connected to a base station 200 by a one-to-many wireless link, and a plurality of base stations 200 are connected to a centralized base by a one-to-one wireless link. It has a configuration connected to each station 300. The centralized base station 300 includes an exchange 301 for exchanging data with the external network 1 and controlling a route, and a transmitting / receiving unit 302 provided for each base station 200. The transmitting / receiving section 302 provided for each base station 200 of the centralized base station 300 provides a transmitting side with a plurality of modulators 303 for modulating transmission data supplied from the external network 1 via the switch 301, A frequency converter 304 provided corresponding to the device 303 for frequency-converting a modulated signal output from each modulator 303 to an intermediate frequency for transmission, and a synthesizer 305 for synthesizing a signal output from each frequency converter 304 And the synthesizer 30
A frequency converter 306 for converting the frequency of the signal output from the transmitter 5 into a radio frequency for transmission;
Transmission high power amplifier 30 for amplifying the signal output from
7 and a transmitting antenna 308. The transmitting / receiving section 302 of the centralized base station 300 is supplied to a receiving side via a receiving antenna 309 for receiving a radio signal transmitted from each base station 200 and a low-noise amplifier 310 from the receiving antenna 309. A frequency converter 311 for converting the frequency of the radio signal into an intermediate frequency signal for reception; a distributor 312 for separating the intermediate frequency signal output from the frequency converter 311; and selecting a desired intermediate frequency signal Tuners 313 for tuning and tuner 31
And a demodulation device 314 that is provided for every 3 and demodulates a signal output from the tuner 313.

The base station 200 has a plurality of sectors S (S11, S12,..., S21, S22,...) Into which a cell C (C1, C2,. Different frequency bands are used between the sectors S. Each subscriber station 100 belongs to one of the sectors S, and communicates with a subscriber station transceiver unit 200SC provided in the base station 200 for each sector S.

For example, as shown in the functional block diagram of FIG. 2, each subscriber station 100 modulates a transmission side with an interface device 101 for exchanging data with the outside and a transmission data supplied from the interface device 101. Modulating device 102, a frequency converting device 103 for frequency-converting a modulated signal output from the modulating device 102 to an intermediate frequency for transmission, and a signal of the intermediate frequency output from the frequency converting device 103 to a radio frequency for transmitting. A frequency conversion device 104 for frequency conversion; a high-power transmission amplifier 105 for amplifying a radio frequency signal output from the frequency conversion device 104; a diplexer 106;
And In addition, each subscriber station 100 sends a diplexer 106 to the receiving side from the antenna 107 for both transmission and reception.
Frequency converter 109 for frequency-converting a radio signal supplied via low-noise amplifier 108 to an intermediate frequency for reception
And a tuner 110 for selecting a signal of a desired intermediate frequency, and a demodulator 111 for demodulating a signal output from the tuner 110. Further, each subscriber station 100 is provided with a microprocessor 112 for performing frequency conversion and tuning in accordance with a signal including information on a reception frequency band transmitted from the base station 200.

The base station 200 includes a receiving antenna 201 for receiving a signal transmitted from each subscriber station 100, and a transmitting / receiving section 200SC for the subscriber station provided for each sector. Distributor 22 for separating a signal supplied from antenna 201 via low noise amplifier 202
0, a band-pass filter 221 that passes only a signal of a desired frequency band, a signal output from the band-pass filter 221 and a local oscillation signal from a local oscillator 222, and received by the reception antenna 201. Mixer 2 for frequency-converting the modulated signal as it is
23, and a band-pass filter 2 for removing a signal other than a desired frequency band from the signal output from the mixer 223.
24, a combiner 225 for combining the signals output from the bandpass filter 224, a transmission high-power amplifier 212 for amplifying the signal output from the combiner 225, and a transmission antenna 213.

Further, as shown in FIG.
0 has a transmitting / receiving unit 200CC for the centralized base station for performing one-to-one wireless communication with the centralized base station. The transceiver unit 200CC for centralized base station has the same configuration as the transceiver unit 200SC for the subscriber station except that the oscillation frequency of the local oscillator 222 is different. That is, a receiving antenna 226 for receiving a signal transmitted from the centralized base station 300, a distributor 220 for separating a signal supplied from the receiving antenna 226 via the low noise amplifier 227, Bandpass filter 221 that passes signals of only the band
And a mixer 223 for mixing the signal output from the band-pass filter 221 with the local oscillation signal from the local oscillator 222 and frequency-converting the modulated signal received by the receiving antenna 226 without change.
A band-pass filter 224 that removes a signal other than a desired frequency band from the signal output from the band-pass filter 23, and a synthesizer 2 that synthesizes a signal output from the band-pass filter 224.
25, a transmission high-output amplifier 228 for amplifying a signal output from the combiner 225, and a transmission antenna 229.

The operation of the point-to-multipoint wireless communication system will be described below with reference to FIGS. Here, FIG. 4 is a diagram showing an example of frequency channel allocation used in the point-to-multipoint wireless communication system. (First Example) For example, the subscriber station 10 belonging to the sector S11
01 (sending subscriber station) 1002, 1003,... Other subscriber stations (receiving subscriber stations) belonging to the same sector S11.
When a communication is made with the subscriber station, a signal is first transmitted from the subscriber station 1001 to the base station 2001, and then a signal is transmitted from the base station 2001 to other subscriber stations 1002, 1003,... (See FIG. 3). Uplink frequency channels U1-> 1 and downlink frequency channels D1-> 1 are allocated to frequency channels used for transmission / reception in the same sector S11. The conversion amount ΔF11 is set (see FIG. 4). The subscriber station 1001 modulates and frequency-converts externally transmitted data and converts the data into base station 200.
1 is almost the same as the conventional technique described with reference to FIG.

A signal transmitted from the subscriber station 1001 to the base station 2001 using the frequency channel U1-> 1 is received by the sector antenna 201 of the base station 2001.
The low-noise amplifier 202 is supplied. Low noise amplifier 202
Is output to the distributor 220 and separated into a plurality of signals. A band-pass filter 221 that allows only the frequency channel U1-> 1 to pass is provided at the subsequent stage of the distributor 220, and only the signal in the frequency channel U1-> 1 is extracted from the output of the distributor 220.
The output of the band pass filter 221 is
3, a local oscillator 222 having an oscillation frequency ΔF11
Mixed with the signal from This oscillation frequency ΔF1
For example, 1 is set in advance for a signal that has passed through the band-pass filter 221. By the above mixing, the signal on the frequency channel U1-> 1 (the transmission frequency band of the transmitting subscriber station) is shifted by ΔF11, and the modulated frequency signal is used as a downlink frequency channel D1-> 1 (the receiving subscriber station). (The receiving frequency band corresponding to the station). Unnecessary components other than the frequency channel D1-> 1 of the frequency-converted signal of the frequency channel D1-> 1 are removed by the band-pass filter 224. The signal output from the band-pass filter 224 is
After being combined with other signals by the signal 25, the signal is output to the transmission high-output amplifier 212. The signal amplified by the transmission high-power amplifier 212 is supplied to the transmission antenna 213, and transmitted from the base station 2001 to the other subscriber stations 1002, 1003, ... in the sector S11. The other subscriber stations 1002, 1003,... Perform frequency conversion based on a preset reception frequency band, and demodulate the signal.
The receiving frequency band D1-> 1 corresponding to the receiving subscriber stations 1002, 1003,... Is not necessarily set in advance, and can be changed by the base station 200 as needed. In this case, a signal containing information on the reception frequency band is transmitted from the base station 200 to the subscriber station 100, and the subscriber station 100 uses the microprocessor 1 based on the signal.
Adjustment such as frequency conversion is performed by using the control unit 12.

In the above case, the frequency channel D
The signal of 1-> 1 can be received by any subscriber station in the sector S11. If a subscriber station and a specific subscriber station (for example, subscriber station 1001 and subscriber station 100
4), the frequency channel U1-> 1 and the frequency channel D1-> 1 are both divided by the number of subscribers, and each subscriber station 100 has a dedicated uplink and a dedicated downlink. Is provided. When a link is provided for each subscriber station 100, the frequency domain may be used as described above, or time division multiplexing or code area multiplexing technology may be used.

(Second example) Also, for example, the subscriber station 1001 belonging to the sector S11 and the subscriber stations 1005, 1006,.
When communication is performed between the subscriber station 1001 and the base station 2001, a signal is transmitted from the subscriber station 1001 to the base station 2001, and the subscriber station transceiver section 200SCa for the sector S11 and the subscriber station for the sector S12 in the base station 2001. A signal is transmitted to the transmission / reception unit 200SCb, and then a signal is transmitted from the base station 2001 to the subscriber stations 1005, 1006,... Belonging to the other sectors S12 (see FIG. 3). The frequency channels used at this time include an uplink frequency channel U
1-> 2, and frequency channel D1-> for downlink
2 is assigned (see FIG. 4). The frequency conversion amount between the two frequency channels is ΔF12, which is set in advance, for example, as in the first example.

A signal transmitted from the subscriber station 1001 to the base station 2001 using the frequency channel U1-> 2 is received by the sector antenna 201 provided in the subscriber station transceiver unit 200SCa of the base station 2001, The signal is supplied to the noise amplifier 202. The signal amplified by the low-noise amplifier 202 is output to the distributor 220 and separated into a plurality of signals. A band-pass filter 221 that passes only the frequency channels U1-> 2 is provided downstream of the distributor 220.
Is provided, and a signal on the frequency channel U1-> 2 is extracted from the output of the distributor 220. The output of the bandpass filter 221 is mixed by the mixer 223 with a signal from the local oscillator 222 having the oscillation frequency ΔF12. Thereby, the frequency channel U
The signal at 1-> 2 is shifted by ΔF12 and frequency-converted as a modulated signal to the downlink frequency channel D1-> 2. Unnecessary components other than the frequency channel D1-> 2 of the frequency-converted signal of the frequency channel D1-> 2 are removed by the band-pass filter 224. The signal output from the band-pass filter 224 is combined with another signal by the combiner 225, and then output to the transmission high-output amplifier 212. The signal amplified by the transmitting high power amplifier 212 is transmitted to the transmitting antenna 21.
3 and transmitted from the base station 2001 to the subscriber stations 1005, 1006,... Belonging to other sectors S12.
In the subscriber stations 1005, 1006,..., The data is demodulated after the frequency conversion according to the frequency channel D1-> 2. Note that, like the first example, the oscillation frequency ΔF12 does not necessarily need to be set in advance. As in the first example, the frequency channel D
The signal of 1-> 2 indicates which subscriber station 1 belonging to the sector S12.
005, 1006,... Can also be received. For example, the same cell C from a certain subscriber station 1001 belonging to the sector S11
When performing communication with a specific subscriber station 1005 belonging to another sector S12, the frequency channel U1-> 2 and the frequency channel D1-> 2 are both divided by the number of subscribers, as in the first example. For each subscriber station 100, a dedicated uplink and a dedicated downlink are provided. In addition, it is also possible to use time division multiplexing or code area multiplexing techniques.

As in the first and second examples, when communication is performed within the same cell C, that is, using the same base station 2001, communication to the centralized base station 300 is not performed. Therefore, the exchange load of the centralized base station 300 does not increase due to the local traffic of the base station 200 unit. In the base station 200, the signal received from each subscriber station 100 is frequency-converted as a modulated signal from the transmission frequency band to the reception frequency band corresponding to the receiving subscriber station, and is transmitted to other subscriber stations 100. Therefore, it is not necessary to provide a demodulator, a modulator, a tuner, and the like in the base station 200, and the cost of the entire system can be reduced.

Third Example On the other hand, communication between different base stations 200 and further communication to an external network are performed via a centralized base station 300. For example, the subscriber station 100 belonging to the sector S11 of the base station 2001 and another base station 20
When communication is performed with the subscriber station 100 belonging to the sector S22 of No. 02, the subscriber station 100 first transmits
01, and a signal is transmitted to the sector S1 in the base station 2001.
A signal is transmitted from the transmitting / receiving section 200SC for the subscriber station to the transmitting / receiving section 200CC for the centralized base station.
From 001, a signal is transmitted to centralized base station 300 via a point-to-point wireless link. Thereafter, in the centralized base station 300, a signal is transmitted from the transmission / reception unit 3021 to the transmission / reception unit 3022 corresponding to the connection destination base station 2002 by the switch 301 in the centralized base station 300, and the transmission / reception unit 3022 transmits the signal to another base station 2002 via the point-to-point wireless line. Is transmitted to another base station 20.
02 transmits a signal to the subscriber station 100 belonging to the sector S22 (see FIGS. 1 and 3). The frequency channels for uplink from the subscriber station 100 belonging to the sector S11 to the centralized base station 300 include frequency channels U1-> used between the subscriber station 100 and the base station 2001.
C and a frequency channel P1-> C used between the base station 2001 and the centralized base station 300 are allocated (see FIG. 4). For the sake of simplicity, assuming that the base station 2001 and the base station 2002 have the same frequency channel configuration, the frequency for downlinking from the centralized base station 300 to the subscriber station 100 in the sector S22 of the base station 2002 is assumed. The channels include the centralized base station 300 and the base station 2
Frequency channel PC-> 2 used between 002 and 002
And the subscriber station 1 belonging to the base station 2002 and the sector S22
00 and the frequency channel DC-> 2 used are assigned (see FIG. 4).

A signal transmitted from the subscriber station 100 belonging to the sector S11 to the base station 2001 using the frequency channel U1-> C is transmitted to the sector antenna 20 of the base station 2001.
1 and supplied to the low noise amplifier 202.
The signal amplified by the low noise amplifier 202
0 and is separated into a plurality of signals. Distributor 220
At the subsequent stage, a band-pass filter 221 that allows only the frequency channel U1-> C to pass is provided, and a signal in the frequency channel U1-> C is extracted from the output of the distributor 220. The output of the band-pass filter 221 is mixed by the mixer 223 with a signal from the local oscillator 222 having the oscillation frequency ΔF1C. As a result, the signal on the frequency channel U1-> C becomes ΔF1
The frequency is shifted by C, and the modulated signal is frequency-converted to an uplink frequency channel P1 → C. The signal on the frequency channel P1-> C is combined with another signal by the combiner 225, and then supplied to the transmitting antenna 229 via the transmitting high-power amplifier 228.
Is transmitted to the centralized base station 300.

The signal transmitted from the base station 2001 is received by the receiving antenna 309 of the centralized base station 300 via the point-to-point wireless link, and supplied to the frequency converter 311 via the low noise amplifier 310. The signal down-converted by the frequency converter 311
After being separated from other signals by 12 and supplied to the tuner 313 group, a signal of a desired frequency channel is extracted. The original digital signal is demodulated by a demodulation device 314 provided at the subsequent stage of each of the tuners 313 and output to the exchange 301. In the exchange 301, the routing destination is determined by the header information included in the digital signal, and if the routing destination is in another base station 2002, the signal is routed to a port connected to the base station 2002. The routed signal is transmitted to the modulation device 303 of the transmission / reception unit 3022 provided corresponding to the base station 2002.
, And then converted to a specific frequency channel, up-converted via a frequency converter 304, a synthesizer 305, and a frequency converter 306, and transmitted from the centralized base station 300 to the base station via a point-to-point wireless link. 200
2 is sent. When data is further transmitted from the centralized base station 300 to the outside, the signal is not routed from the exchange 301 to the transmission / reception unit 302 but is transmitted from the exchange 301 to the external network.

From the centralized base station 300 to the frequency channel P
The signal transmitted to base station 2002 using C-> 2 is received by antenna 226 of base station 2002 and supplied to low noise amplifier 227. The signal amplified by the low-noise amplifier 227 is output to the distributor 220 and separated into a plurality of signals. The band-pass filter 22 that allows only the frequency channel PC-> 2 to pass after the distributor 220
1 is provided, and a signal on the frequency channel PC-> 2 is extracted from the output of the distributor 220. The output of the bandpass filter 221 is mixed by the mixer 223 with a signal from the local oscillator 222 having the oscillation frequency ΔFC2. As a result, the signal on the frequency channel PC-> 2 is shifted by ΔFC2, and the modulated signal is frequency-converted to the downlink frequency channel DC-> 2 as it is. Unnecessary components other than the frequency channel DC-> 2 of the frequency-converted signal of the frequency channel DC-> 2 are removed by the band-pass filter 224. Subscriber station transmitting / receiving section 2 corresponding to sector S22
The signal output from the 00SCb band-pass filter 224 is combined with other signals by the combiner 225 and then output to the transmission high-output amplifier 212. The signal amplified by the transmission high-power amplifier 212 is supplied to the transmission antenna 213 and transmitted from the base station 2001 to the sector S22.
Is transmitted to the subscriber station 100 belonging to. The signal of the frequency channel DC-> 2 can be received by any of the subscriber stations 100 belonging to the sector S12. If sector S12
When transmitting to a specific subscriber station 100 belonging to
The frequency channel DC-> 2 may be divided by using frequency multiplexing, time division multiplexing, and code area multiplexing techniques. The divided channels can be directly designated by the exchange 301 from the centralized base station 300, similarly to the channel corresponding to the sector S. When communication is performed via the centralized base station 300 as in the third example, the reception frequency band of the subscriber station 100 can be selected by the switch 301, and high-speed channel switching can be performed. . Also, the base station 200 has a modulator,
There is no need to provide a demodulator or the like, and the cost of the base station and the entire system can be reduced. As described above, according to the point-to-multipoint wireless communication system according to the present embodiment, the local traffic per base station is based on the fact that the signal received from each subscriber station is converted from the transmission frequency band to the reception frequency corresponding to the receiving subscriber station. A point-to-multipoint wireless communication system that reduces the load on the centralized base station while reducing the cost required for the base station because the frequency is converted as it is to the band and transmitted to other subscriber stations and processed in the base station. Can be provided.

[0035]

In the above embodiment, the base station 200 converts the signal received from each subscriber station 100 from a transmission frequency band to a reception frequency band corresponding to the receiving subscriber station as it is as a modulated signal and performs other frequency conversion. The switching process has been performed by transmitting the signal to the subscriber station 100. As shown in FIG. 5, after the signal received by the base station 200 is frequency-converted to an intermediate frequency, the receiving subscriber station is transmitted in the intermediate frequency band. May be selected, and the frequency may be converted to the selected reception frequency band with the modulated signal as it is. The configuration of the point-to-multipoint wireless communication system according to this embodiment is different from that of the point-to-multipoint wireless communication system according to the above-described embodiment.
2 is a configuration of a base station.

As shown in FIG. 5, the base station 200 'according to this embodiment transmits a signal transmitted from each subscriber station 100 to a subscriber station transceiver 200' SC provided for each sector S. Receiving antenna 201 'for receiving the
A low-noise amplifier 202 'for amplifying the signal supplied from the receiving antenna 201', a frequency conversion device 203 'for converting the signal output from the low-noise amplifier 202' to an intermediate frequency for reception, and a distributor 204 'And subscriber station 10
A tuner 205 'for tuning to an intermediate frequency for reception in synchronization with 0, a matrix exchanger 500 for switching a signal at the intermediate frequency, and an intermediate switch corresponding to the subscriber station 100 which is switched by the matrix converter 500. A frequency converter 209 'for outputting a frequency signal, a synthesizer 210' for synthesizing signals output from the respective frequency converters 208 ', and a frequency converter 211 for converting a signal from the synthesizer 210' to a radio frequency. And a transmission high-power amplifier 21 for amplifying the output of the frequency converter 211 '.
2 ′ and a transmitting antenna 213 ′.

The base station 200 'is located at the centralized base station 3
And a centralized base station transmitting / receiving unit 200'CC for performing one-to-one wireless communication with the 00. This transmitting / receiving unit 2 for the centralized base station
00CC 'has substantially the same configuration as the subscriber station transceiver unit 200'SC. That is, a receiving antenna 226 'for receiving a signal transmitted from the centralized base station 300.
A low-noise amplifier 227 'for amplifying the signal supplied from the receiving antenna 226', and a low-noise amplifier 227 '
A frequency converter 228 'for converting the signal output from the receiver to an intermediate frequency for reception, a distributor 229', a tuner 230 'for tuning to the subscriber station 100 and selecting an intermediate frequency for reception, A matrix exchanger 501 for switching a signal at a frequency, and a matrix converter 50
1 to output a signal of an intermediate frequency corresponding to the subscriber station 100.
And a synthesizer 232 'for synthesizing signals output from the respective frequency converters 231', a frequency converter 233 'for converting a signal from the synthesizer 232' to a radio frequency, and an output of the frequency converter 233 '. It has a transmitting high power amplifier 234 'for amplification and a transmitting antenna 235'.
The transmitting / receiving unit for centralized base station 200 ′ CC includes a demodulation device 502 for demodulating a signal including information on a reception frequency band transmitted from the centralized base station 300 as necessary.
A CPU 503 for processing a signal output from the demodulation device 502 and controlling the matrix converter 501;
And a modulation device 504 that modulates the digital signal output from the 503. The operation of the point-to-multipoint wireless communication system according to this embodiment is also similar to that of the point-to-multipoint wireless communication system according to the above embodiment.

(Fourth Example) The first example in the above embodiment.
As in the example of the above, for example, the subscriber station 1 belonging to the sector S11
001 is another subscriber station 100 belonging to the same sector S11.
, 1003,..., First, a signal is transmitted from the subscriber station 1001 to the base station 2001 ′, and then the base station 2001 ′ transmits the other subscriber stations 1002, 100
Signals are transmitted to 3,. A signal transmitted from the subscriber station 1001 to the base station 2001 ′ using the uplink frequency channel dedicated to the subscriber station 1001 is transmitted to the base station 200.
The signal is received by the 1 'sector antenna 201' and supplied to the low noise amplifier 202 '. The signal amplified by the low-noise amplifier 202 'is down-converted to an intermediate frequency for reception by the frequency converter 203'. The signal of the intermediate frequency for reception is distributed by the distributor 204 'and supplied to the tuner 205'. A signal of a desired intermediate frequency is selected by a tuner 205 'tuned to the subscriber station 1001, and is output to a matrix converter 500 using a video switch or a low-priced switch corresponding thereto. Sector S by intermediate frequency matrix converter 500
The connection destination is set to the frequency converter 209 'corresponding to the S11, and the signal is frequency-converted by the frequency converter 209' to the downlink frequency channel corresponding to the sector S11. The signals output from the respective frequency converters 209 'are combined by a combiner 210' and supplied to a transmitting antenna 213 'via a frequency converter 211' and a transmitting high-power amplifier 212 ', and the other signals in the sector S11 are transmitted. Are transmitted to the subscriber stations 1002, 1003,... In this example, the uplink and downlink frequency channels corresponding to each subscriber station are used. However, one frequency channel may be shared by a plurality of subscriber stations 100 in the same sector S by a time division multiplexing technique. It is possible. Since the matrix converter 500 is a switch capable of high-speed switching such as an analog switch, for example, the frame time is set to 10 m.
s is divided into ten 1 ms time slots, and signals from ten subscriber stations 100 can be alternately supplied to one frequency converter 209.
Further, each frequency channel can be divided into narrower frequency bands and shared by a plurality of subscriber stations 100 by frequency multiplexing.

Fifth Example Similarly to the second example in the above embodiment, for example, the subscriber station 1001 belonging to the sector S11 and another sector S of the same base station 2001 '
, Which belong to the sector S11 in the base station 2001 ', a signal is transmitted from the subscriber station 1001 to the base station 2001'. A signal is transmitted from the station transmitting / receiving section 200'SCa to the subscriber station transmitting / receiving section 200'SCb for the sector S12, and then a signal is transmitted from the base station 2001 'to the subscriber stations 1005, 1006, ... belonging to the other sectors S12. Sent. The operation of the fifth example is the same as that of the fourth example except that connection setting is performed by the matrix conversion device 500 to the frequency conversion device 205 'of the subscriber station transceiver unit 200'SCb corresponding to the sector S12. The details are omitted because they are the same. In the above fourth and fifth examples,
When communication is performed in the same cell C, that is, using the same base station 2001, communication to the centralized base station 300 is not performed. Therefore, the exchange load of the centralized base station 300 does not increase due to the local traffic of the base station 200 ′. In the base station 200, each subscriber station 10
In order to perform exchange processing without modulating and demodulating the signal received from 0,
There is no need to provide a demodulator, a modulator, and the like in the base station 200, and the cost of the entire system can be reduced.

(Sixth Example) On the other hand, communication between different base stations 200 is performed via the centralized base station 300 as in the third example in the above embodiment. For example, the subscriber station 100 belonging to the sector S11 of the base station 2001 'and the subscriber station 10 belonging to the sector S22 of another base station 200'
0, a signal is first transmitted from the subscriber station 100 to the base station 2001 ′.
1 ', the subscriber station transceiver unit 200' for the sector S11.
A signal is transmitted from the SC to the centralized base station transmitting / receiving section 200'CC, and then a signal is transmitted from the base station 2001 'to the centralized base station 300 via the point-to-point wireless link. afterwards,
In the centralized base station 300, a signal is transmitted from the transmission / reception unit 302 to the transmission / reception unit 302 corresponding to the connection destination base station 2002 by the switch 301, and the signal is transmitted from the transmission / reception unit 302 to another base station 200 via the one-to-one wireless line. Is transmitted, and a signal is transmitted from another base station 200 to the subscriber station 100 belonging to the sector S22. The operation of this sixth example is
The difference from the fourth and fifth examples is that the base station 2
001 ′ matrix switching devices 500 and 501, the frequency conversion device 2 of the centralized base station transceiver unit 200′CC.
05 'and the communication is performed with another base station 200 via the centralized base station 300. The operations are substantially the same as those in the third, fourth, and fifth examples. Therefore, the description is omitted.

The routing (path control) by the matrix switching devices 500 and 501 in the fourth to sixth examples can be used in a fixed manner.
00 to the base station 20.
It is also possible to switch by transmitting to 0 '. In this case, for example, as an order wire for a switching command, a frequency band other than user data is secured,
A method of sending routing control information separately from the transmission of user data is used. In this case, a demodulation device 502 and a demodulation device 503 dedicated to the route control information are required, and by arranging the CPU 503 in the base station 200 ', it becomes possible to perform advanced route operation. As shown in FIG. 6, it is also possible to combine the point-to-multipoint wireless communication system according to the above-described embodiment with the point-to-multipoint wireless communication system according to the above-described example. In this example, communication between the subscriber stations 100 belonging to the same sector S is performed in the same manner as in the first example. When communication is performed between the specific subscriber stations 100, the frequency channel can be divided by frequency multiplexing or time division multiplexing and shared by a plurality of subscriber stations 100. In addition, communication between the sectors S or the centralized base station 3
The communication via 00 is performed using a matrix switch, as in the above embodiment. This routing can, of course, be performed according to the route control information from the centralized base station 300. When the radio signal received by the base station is converted into an intermediate frequency band as described above, and the path is selected using a matrix converter in the intermediate frequency band, the selection of the frequency channel at each subscriber station is performed as it is. Compared with the selected one-to-many wireless communication system according to the above-described embodiment, the number of expensive quasi-millimeter wave band bandpass filters 224 can be significantly reduced, so that the cost of the entire system can be reduced.

In such a routing, connection requests from the subscriber station 100 are collected at the centralized base station 300 via the base station 200, and at that time, in the base station 200 according to the availability of the intermediate line. By automatically selecting the routing or the routing via the centralized base station 300, a limited frequency band can be effectively used. In the exchange 301 in the centralized base station 300, route management via the centralized base station 300 is usually performed, so if the mechanism for routing in the base station 200 of the present invention is combined, the exchange 301 is configured. The above function can be realized by giving the above-mentioned selection function to a computer that performs the function. Such a one-to-many wireless communication system is also an example of the one-to-many wireless communication system in the present invention.

In the above embodiment, the base station 200
And the centralized base station 300 are directly connected via a wireless line, but a repeater may be provided between them. This repeater can be realized with a simple configuration as long as it has a frequency converter for relaying each wireless link connected to the repeater. Further, the repeater may also have a function of communicating with the subscriber station of the base station. Such a one-to-many wireless communication system is also an example of the one-to-many wireless communication system in the present invention. In addition, the above base station 20
No. 0 can be downsized and has environmental resistance because it does not have heavy equipment such as modulators, demodulators, and switches, which are heavy and consume a lot of power, require maintenance, and do not have internal equipment that requires air conditioning. It is easy to install in a place with good visibility, such as the top of a tower or the top of a mountain. Thereby, the area covered by one base station 200 can be expanded.

[0044]

As described above, according to the first aspect of the present invention, even when communication is performed from an arbitrary subscriber station to another subscriber station via the base station, a signal received by the base station is received. Since the radio signal from the transmitting subscriber station is converted into a receiving frequency band corresponding to the receiving subscriber station as a modulated signal, the base station includes a modulator, a demodulator, a frequency converter to an intermediate frequency, a tuner. It is not necessary to provide such a device, and the cost of the base station and the entire system can be reduced. According to the second aspect of the present invention, the frequency conversion amount between the transmission frequency band of the transmitting subscriber station and the receiving frequency band of the receiving subscriber station is set in advance.
Communication can be performed from an arbitrary subscriber station to a specific subscriber station in the same base station without using an expensive switch, and the cost of the base station and the entire system can be reduced. According to the third aspect of the present invention, similar to the point-to-multipoint wireless communication system according to the first aspect,
The radio signal from the transmitting subscriber station received by the base station is once converted to an intermediate frequency, and then converted from the intermediate frequency to a reception frequency band as a modulated signal and transmitted.
It is not necessary to provide a modulation device and a demodulation device in the base station, and it is possible to use an inexpensive matrix switch by selecting the reception frequency band of the receiving subscriber station in the intermediate frequency band. The overall cost can be reduced. Further, by selecting the reception frequency band in the intermediate frequency band, the same frequency band can be routed to a plurality of subscriber stations, and the required frequency channels can be greatly reduced. According to the fourth or fifth aspect of the present invention, a radio signal from the transmitting subscriber station is frequency-converted to a receiving frequency band allocated to a sector to which the receiving subscriber station belongs as a modulated signal. Therefore, even when communication is performed between subscriber stations belonging to the same sector or between different stations, the cost of the base station and the entire system can be reduced in the same manner as in the invention described in claim 1 or 2. Can be. According to the sixth aspect of the present invention, even when the allocation of the reception frequency band corresponding to each subscriber station is changed in the base station, the correct channel selection can be performed in the subscriber station. Becomes

According to the invention described in claim 7 or 8, even when a base station is connected to another base station or an external network via the centralized base station, a local base station unit can be used. Since the switching load due to traffic is processed in the base station, the operation can be smoothly performed without excessive concentration on the centralized base station. In addition, it is possible to use a switch having a relatively low processing capacity for the exchange of the centralized base station, and it is possible to reduce the cost. According to the ninth aspect of the present invention, even when the allocation of the reception frequency band corresponding to each subscriber station is changed in the centralized base station, the correct channel selection can be performed in the subscriber station. It becomes possible. According to the tenth aspect, a route is selected from the centralized base station according to the availability of the intermediate line, so that a limited frequency band can be effectively used. According to the eleventh aspect of the present invention, since the base station is installed in a place with good visibility such as the upper part of a tower or the top of a mountain, the area covered by one base station can be expanded.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a point-to-multipoint wireless communication system according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a subscriber station and a base station in the point-to-multipoint wireless communication system.

FIG. 3 is a diagram for explaining communication via a centralized base station in the point-to-multipoint wireless communication system.

FIG. 4 is a diagram showing an example of frequency channel allocation used in the point-to-multipoint wireless communication system.

FIG. 5 is a diagram showing a schematic configuration of a point-to-multipoint wireless communication system according to an embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of a point-to-multipoint wireless communication system according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a conventional one-to-many wireless communication system.

FIG. 8 is a diagram for explaining a concept of a cell of a base station and a connection between the base station and a centralized base station.

FIG. 9 is a diagram for explaining another example of the conventional one-to-many wireless communication system.

[Explanation of symbols]

 Reference Signs List 100 subscriber station 200 base station 221, 224 bandpass filter 222 local oscillator 223 mixer 300 centralized base station 500, 501 matrix conversion device

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H04Q 7/30

Claims (11)

[Claims] A one-to-many wireless communication system in which a plurality of subscriber stations wirelessly communicate with a base station using a predetermined transmission frequency band and a reception frequency band allocated to a microwave, quasi-millimeter wave, or millimeter wave band, The base station converts the radio signal received from the transmitting subscriber station from the transmitting frequency band to a receiving frequency band corresponding to the receiving subscriber station as a modulated signal. A one-to-many wireless communication system characterized by being transmitted to a subscriber station. 2. The one-to-many wireless communication system according to claim 1, wherein a frequency conversion amount between a transmission frequency band of the transmission side subscriber station and a reception frequency band of the reception side subscriber station is set in advance. 3. A radio signal from a transmitting subscriber station received by the base station is frequency-converted from a transmission frequency band to an intermediate frequency band, and is modulated to a reception frequency band selected in the intermediate frequency band. The one-to-many wireless communication system according to claim 1, wherein the frequency conversion is performed as it is. 4. The base station has a plurality of sectors using frequency bands different from each other, and a radio signal from a transmitting side subscriber station received by the base station is converted from a transmission frequency band as a modulated signal to the above-mentioned radio signal. 2. A reception frequency band converted to a reception frequency band allocated to a sector to which a receiving subscriber station belongs.
4. The point-to-multipoint wireless communication system according to any one of claims 1 to 3. 5. The point-to-multipoint wireless communication system according to claim 4, wherein the transmitting subscriber station and the receiving subscriber station belong to different sectors. 6. A signal including information on a reception frequency band is transmitted from the base station to the subscriber station.
The one-to-many wireless communication system according to any one of the above. 7. The base station connects via a point-to-point wireless link to a centralized base station having a switching function of once demodulating a received signal, setting a connection destination, modulating again, and transmitting the modulated signal to the connection destination. The one-to-many wireless communication system according to any one of claims 1 to 6, wherein 8. The point-to-multipoint wireless communication system according to claim 7, wherein the base station is connected to another base station via the centralized base station. 9. The point-to-multipoint wireless communication system according to claim 7, wherein a signal including information on a reception frequency band is transmitted from the centralized base station to the base station. 10. When a connection request from one subscriber station to another subscriber station is made to the centralized base station via the base station, switching of the centralized base station is performed according to the availability of an intermediate line. 10. The centralized base station selects whether to use a communication path via a transmitter or a communication path for transmitting and receiving a modulated signal within the base station as it is, according to any one of claims 7 to 9. A one-to-many wireless communication system as described. 11. The point-to-multipoint wireless communication according to claim 7, wherein the centralized base station is installed inside a building, and the base station is installed in a place with good visibility. system.