JPH0670359A - Mobile body communication system - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] The present invention provides a mobile communication system in which even if traffic conditions in a service area change, the switching center can immediately respond without changing the equipment configuration of the base station. The purpose is to do. A base station is provided with a set of wide band amplifying means and a signal transmitting / receiving means for transmitting a signal between this means and a switching station through a single transmission path, and the switching station is provided with the above-mentioned signal transmitting / receiving means. And a transmission / reception control means for detecting a target frequency from a signal input / output to / from this means, controlling it for use in communication, and managing whether the detected frequency is usable or impossible for communication, A signal conversion control means for converting a signal of a frequency detected by the means into a baseband signal and a control of converting the baseband signal from the exchange into a signal of a target frequency, a transmission / reception control means and a signal conversion control means. Is provided with a connection unit that connects under the control of the transmission / reception control unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system intended to economically absorb fluctuations in communication traffic in a service area in mobile communication.

In mobile communication, when carrying necessary traffic in a certain service area, a required number of radios are installed in a base station which controls communication in that area, and a user's call is carried through the radio. I am trying.

However, the amount of traffic changes from moment to moment due to a discrete set of people, and when facilities for providing public services in the area become available, the amount of traffic to be carried also changes, which makes it difficult to connect to the line. In addition, the equipment will be idle in some areas.

Therefore, there is a demand for a mobile communication system in which the number of wireless equipment can be easily increased or decreased as the number of users increases or decreases.

[0005]

2. Description of the Related Art FIG. 3 shows a schematic configuration diagram of a conventional mobile communication system, and the description thereof will be given. As shown in this figure, in the conventional system, base stations 11 _{1 to} 11 _n are installed in each of a plurality of communication service areas 1 to N, and each base station 11 ₁
Antenna duplexer 14 connected to the common antenna 13 by a plurality of the antennas of the wireless device 12 to collectively to 11 _n
And a connection device 1 for connecting each radio 12 and the exchange 16
5 and other power supply devices and maintenance-related equipment (not shown). However, the terminals of the wireless device 12 and the exchange 16 are connected one to one.

Therefore, the wireless device 12, the exchange interface unit of the connection device 15, and the relay line 18 predict the traffic volume of the service area and are installed in the base stations 11 _{1 to} 11 _n as necessary wireless equipment. Become.

The operation in such a configuration will be described.
When the user makes a call using the mobile phone 17, the information indicating “call” is transmitted as a radio wave using a control frequency.

Radio waves are transmitted from the antenna 13 and the antenna duplexer 1.
4 is received by the wireless device 11 ₁ that controls communication, and the information of “call” is demodulated here and input to the connection device 15.

The connection device 15 communicates with the user's mobile phone 17 via the radio 12, searches for frequencies that can be used for communication, and grants the right to use the searched frequency to the mobile phone 1.
Give to 7.

Thereafter, the mobile phone 1 such as the telephone number of the other party
The information transmitted from 7 is the wireless device 12, the connection device 1
5 and the relay line 18 to the exchange 16. Here, a call is made by connecting the line to the intended party according to the information received by the exchange 16.

[0011]

By the way, in the above-mentioned mobile communication system, one radio 12 of the base stations 11 _{1 to} 11 _n , the exchange interface section of the connection device 15, and the relay line 18 are one. Since it is used exclusively for making calls, it is installed according to the traffic volume in the service area.

[0012] Therefore, once the equipment such as the radios 12 is installed, the number thereof is fixed, and even if the traffic increases, it is not possible to cope with the increase in the traffic unless the expansion is performed.

Further, when the traffic is reduced, the facilities such as the radio 12 are left over unless they are moved to another area. That is, in the conventional mobile communication system, even if the traffic condition of the service area changes, it is difficult to immediately cope with it,
In addition, there was a problem that it cost a lot of money.

The present invention has been made in view of the above circumstances, and even if the traffic conditions in the service area change, the switching center can immediately respond without changing the equipment configuration of the base station. It is an object of the present invention to provide a mobile communication system capable of performing the above.

[0015]

FIG. 1 shows the principle of the present invention. In the figure, 21 _{1 to} 21 _n are base stations installed in different communication service areas, and 22 is each base station 21 ₁ to
It is an exchange station cable-connected to 21 _n .

Each of the base stations 21 _{1 to} 21 _n has a wide band amplifying means 2 for amplifying a signal transmitted / received by the antenna 25.
6 and a first signal transmitting / receiving means 27 for transmitting a signal transmitted between the wide band amplifying means 26 and the exchange station 22 through one transmission line 23, and the exchange station 22 comprises:
A second signal transmitting / receiving unit 28 having the same function as the first signal transmitting / receiving unit 27, and a control for detecting a target frequency from a signal input / output to / from the second signal transmitting / receiving unit 28 and using the detected frequency for communication. Transmission / reception control means 29 for managing whether the selected frequency can be used for communication or not, and a signal of the frequency detected by the transmission / reception control means 29 is converted into a baseband signal to the exchange 32. The transmission / reception control means 29 controls the transmission / reception control means 29, the transmission / reception control means 29, and the signal conversion control means 31 for controlling the transmission of the baseband signal transmitted from the exchange 32 into a signal of a target frequency. The connection means 30 is provided for connection according to control.

[0017]

In the present invention described above, the first and second signal transmitting / receiving means 27, 28 are E / O converters for mutually converting electric signals / optical signals, and the E / O converters 27, 28 are used.
An optical cable 23 is defined as one transmission line connecting the two.

That is, in such a configuration, signals of all frequency bands used in the mobile phone (mobile station) are provided by one antenna 25, wide band amplifying means 26, and E / O.
It is guided to the exchange 22 via the converter 27 and the optical cable 23.

That is, the radio wave states of all areas are directly brought into the exchange 22. In the exchange 22, the transmission / reception control means 29 corresponding to the base stations 21 _{1 to} 21 _n searches the signal converted into an electric signal to detect the transmission or detects other signals in the same manner as the normal base station does. Detect the frequency used.

When a certain frequency is detected by the signal conversion control means 29, the signal is demodulated at that frequency, and it is judged whether the signal is transmitted or another mobile phone is in use. If the signal is transmitted, the connection means 30 is controlled. The signal conversion control means 31 is connected.

The signal conversion control means 31 receives the notification of the frequency from the transmission / reception control means 29, adjusts its own transmission / reception frequency to the frequency, and thereafter communicates with the mobile telephone as a normal radio of a base station.

When the mobile telephone is called from the exchange 22, when the incoming call from the exchange 32 is transmitted to the signal conversion control means 31, the signal conversion control means 31 calls the base station whose location is registered beforehand from the mobile telephone. , The exchange 32, or the management table of the higher-level management station, and has the transmission / reception control means 29 connected to the target base station via the connection means 30.

The transmission / reception control means 29 informs the signal conversion control means 31 of the unused frequencies managed by itself. The signal conversion control means 31 sets its own frequency to that frequency, converts the call information into a radio frequency, and transmits it to the target area via the base station.

In the subsequent operation, when the mobile phone responds, as usual, the switch 32 connects the caller and the mobile phone to make a call. The operation is exactly the same when a plurality of communications are carried out in the same area, but the transmission / reception control means 29
As long as there is a frequency that can be used by the signal conversion control means 31 used for each call in the frequency managed by the above, a plurality of frequencies are connected between the base station and the switching center 22 by connecting a number of wired ORs. Can be exchanged.

That is, regardless of the fluctuation of traffic,
It is possible to provide a mobile communication system that does not need to change the device configuration.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a mobile communication system according to an embodiment of the present invention.

In this figure, 21 _{1 to} 21 _n are base stations respectively installed in a plurality of communication service areas, and 22 is a switching center connected to the base stations 21 _{1 to} 21 _n by an optical cable 23.

Each of the base stations 21 _{1 to} 21 _n has an antenna 25.
, A broadband amplifier 26, and an electric signal / optical signal converter (E
/ O converter) 27. The antenna 25 transmits and receives radio waves for communicating with a mobile phone (not shown).

The broadband amplifier 26 covers the frequency band of the target radio signal transmitted and received by the antenna 25. The E / O converter 27 converts an electric signal into an optical signal and vice versa. The E / O converter 27 is provided in both directions of sending and receiving with respect to the antenna 25, and the wide band amplifier 26 is also provided. Similarly, it is prepared in both directions.

Further, the E / O converter 27 is connected to the optical cable 2 for connecting the base stations 21 _{1 to} 21 _n and the exchange 22.
3 is connected, and the other switching center 22 is also equipped with an E / O converter 28 connected to the optical cable 23.

The exchange 22 has an E / O converter 28, a transmission / reception control unit 29, a switch 30, and a signal conversion control unit 31.
And an exchange 32. The transmission / reception control unit 29 monitors a signal transmitted / received via the E / O converter 28 and manages a used channel (frequency) and the like, and includes a synthesizer 34, a control unit 35, and a memory unit 36. And is configured.

The synthesizer 34 detects a high frequency signal transmitted and received via the E / O converter 28 and also detects the frequency thereof. The control unit 35 detects the call from the mobile phone from the information of the synthesizer 34 and notifies the switch 30 of this, and the signal conversion control unit 31 and the transmission / reception control unit 2 are notified.
9 is connected, the management information of the used frequency is stored in the memory unit 36, and the management information is read to inform the signal conversion control unit 31 of available frequencies.

The switch 30 has the control unit 35 as described above.
Signal conversion control unit 31 and transmission / reception control unit 29 according to the control of
Is to connect with. The signal conversion control unit 31 selects a target frequency from the high-frequency signals sent via the optical cable 23, converts the selected frequency into a baseband signal, and then the exchange 3
2 or the baseband signal sent from the exchange 32 is converted into a target high-frequency signal, and the optical cable 23
The transmission control is performed to the base stations 21 _{1 to} 21 _n via the wireless LAN, and includes a wide band amplifier 38, a conversion unit 39, and a control unit 40.

The wide band amplifier 38 covers the frequency band of the target radio signal, and the converter 39 mutually converts the high frequency signal and the base band signal.
The control unit 40 exchanges information with the exchange 32 and the conversion unit 3
9 is controlled.

Next, the operation will be described. A mobile phone (not shown) automatically or manually performs position registration when moving from an area where it has been to date to another area.

In the position registration operation, a number peculiar to the mobile phone is transmitted to a nearby base station (eg, 21 ₁ ) by radio waves assigned for control. That is, the base station 21 ₁ is requested to use the control frequency for the frequency (channel) for the communication, and after the base station 21 ₁ is notified of the communication frequency, the position is determined by using the frequency. The procedure for registering is taken.

The base station 21 ₁ receives the radio wave coming from the area by the antenna 25, and amplifies the signals of all frequencies used by the system by the wide band amplifier 26. And E
The electric signal amplified by the / O converter 27 is converted into an optical signal and sent to the exchange 22 via the optical cable 23.

At the exchange 22, the E / O converter 28 is temporarily turned on.
Converts optical signals into electrical signals. The electric signal (high frequency signal) is input to the synthesizer 34. The synthesizer 34 is constantly searching within the target frequency band,
When the frequency of the radio wave transmitted from the mobile phone is detected from the input high frequency signal, the control unit 35 is notified of it.

Since the control section 35 stores the frequency currently being used in the memory section 36, if the synthesizer 34 is used.
If the frequency notified by is in use, it instructs the synthesizer 34 to detect another frequency. On the other hand, if it is not in use, the control unit 35 demodulates the high frequency signal and judges the contents, and confirms that it is a frequency (channel) request from a mobile phone belonging to the system.

Next, the control unit 35 searches the available frequency (channel) from the information managed in the memory unit 36 as the frequency to be used for communication with the mobile phone in the future by using the control frequency. This is transmitted to the mobile phone, and the fact that the frequency is being used is stored in the memory unit 36.

The mobile phone sets the circuit to the instructed frequency and waits for the next instruction from the base station 21 ₁ . Further, the control unit 35 controls the switch 30 so as to connect the transmission / reception control unit 29 to the signal conversion control unit 31 in the vacant or predetermined group.

After this connection, the transmission / reception control unit 29 notifies the signal conversion control unit 31 of the frequency transmitted to the mobile phone and the fact that the mobile phone has been activated. Upon receiving the information, the signal conversion control unit 31 sets its own circuit to the instructed frequency and sends out a signal called a synchronization burst for establishing a communication path with the mobile phone.

This signal is converted into an optical signal by the E / O converter 28, transmitted to the base station 21 ₁ via the optical cable 23, converted into an electric signal again by the E / O converter 27, and then at a radio frequency. It is radiated from the antenna 25.

When the mobile phone receives the radiated radio wave, it transmits a position registration request by radio wave. After that, as described above, the exchange 32 is further transmitted from the base station 21 ₁ to the exchange 22 via the E / O converters 27 and 28 and is communicated with the signal conversion control unit 31 connected thereto. The location is registered in the database of a higher station (not shown).

In addition to this, the operation principle of outgoing and incoming calls is also the same.
This is performed by instructing the mobile phone and the selected signal conversion control unit 31 of the frequency (channel) to be used by the transmission / reception control unit 29.

The base stations 21 _{1 to} 21 _n and the exchange 22
Although the optical cable 23 is used for the transmission line connecting the and, it may be any one as long as it can transmit a signal in the target frequency band, and for example, a coaxial cable may be used.

As described above, according to the mobile communication system of the present embodiment, the radio equipment of the base station has the broadband amplifier and the E / E regardless of the traffic volume of the service area.
It's easy because you only need to prepare one set with O converter.
In addition, the base station can be installed economically.

[0048]

As described above, according to the present invention,
Even if the traffic conditions of the service area change, there is an effect that the switching center can immediately respond without changing the device configuration of the base station.

Further, since it is sufficient to provide the base station with the wide band amplifier for amplifying the transmission / reception signal and the means for transmitting the signal transmitted between the wide band amplifier and the exchange through the single transmission line, the base station can be provided. There is an effect that it can be installed easily and economically.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a schematic configuration of a conventional mobile communication system.

[Explanation of symbols]

21 _{1 to} 21 _n Base station 22 Switching station 23 Transmission path 25 Antenna 26 Wideband amplification means 27, 28 Signal transmission / reception means 29 Transmission / reception control means 30 Connection means 31 Signal conversion control means 32 Exchanger

Claims (2)

[Claims] 1. A mobile communication system in which a plurality of base stations (21 _{1 to} 21 _n ) cable-connected to an exchange (22) perform radio wave communication with mobile stations within its own communication area. Each of the stations (21 _{1 to} 21 _n ) has a wideband amplification means (26) for amplifying a signal transmitted and received by the antenna (25), and is transmitted between the wideband amplification means (26) and the exchange (22). A first signal transmitting / receiving means (27) for transmitting a signal to be transmitted through one transmission line (23), and the switching center (22) is provided with a second signal having the same function as the first signal transmitting / receiving means (27). The target frequency is detected from the signal input / output means (28) and the signal input / output to / from the second signal transmission / reception means (28), the detected frequency is used for communication, and the selected frequency is selected. A transmission / reception control means (29) for managing whether the frequency can be used for communication and a signal of the frequency detected by the transmission / reception control means (29) Converted to a band signal and sent to the exchange (32),
Signal conversion control means (3) for controlling to convert a baseband signal sent from the exchange (32) into a signal of a target frequency.
1), the transmission / reception control means (29) and the signal conversion control means (31),
Connection means for connection under the control of the transmission / reception control means (29)
A mobile communication system comprising: (30). 2. The transmission / reception control means (29), a memory section, and a synthesizer for detecting a signal input / output to / from the second signal transmission / reception means (28) and a frequency thereof.
The connection means (30) can be controlled according to the information from the synthesizer, and the management information of the used frequency can be stored in the memory section, or the management information can be read and used for the signal conversion control means (31). A wideband amplifier for amplifying a signal passing through the connecting means (30), and a first control section for controlling to notify a different frequency, the signal conversion control means (31), and the wideband amplifier. A conversion unit for converting the output signal of the baseband signal to a baseband signal and sending it to the exchange (32), and converting the baseband signal sent from the exchange (32) into a signal of a target frequency; The mobile communication system according to claim 1, wherein the mobile communication system comprises a control unit that performs control.