JPH06338835A - Base station device of radio telephone system - Google Patents

Abstract

PURPOSE:To constitute a base station where an extension is easily performed for the increase of traffic at low cost. CONSTITUTION:This device has plural reception circuits 5 where two units selecting and amplifying the reception signal processed by a distribution amplifier circuit 3 from two transmission and reception shared antennae 1 for executing a diversity system are made a pair. According to the reception intensity level from the reception circuit 5, a reception intensity comparison decision circuit 8 and a control circuit 9 controls a transmission antenna changeover switch 7 so as to perform a transmission by an antenna whose reception state is excellent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station device for a radio telephone system.

[0002]

2. Description of the Related Art Conventionally, a digital cordless telephone device used in a telepoint system or the like includes a base station (line control device, radio base station) connected to an exchange through a line and a plurality of mobile radio terminals (cell phones). ) And a wireless transmission / reception system between them has a plurality of frequency channels obtained by time division multiplexing (TDM) the wireless channels, and uses the wireless channels as slots in the TDM to match slots for control signals and communication. TDMA / TDD system consisting of frequency channels f ₁ every slot and frequency channel f _C1 is call slots with are common.

In Japan as well, in order to operate these systems in accordance with the national standard for public purposes,
"Simple mobile phone system (personal handy phone)" that was partially reported by the Telecommunications Technology Council on March 22
Technical design ”(June 22, 1992) and the RCR standard“ Second-generation cordless telephone system standard (RCR STD-28) ”formulated on March 17, 1993. It is being appreciated.

As a transmitting / receiving device in the radio base station of such a system, the one shown in FIG. 2 can be considered. In FIG. 2, reference numeral 21 is an antenna for transmitting and receiving radio signals, 22 is a transmission / reception changeover switch for switching between transmission and reception, and 23 is a plurality of receiving circuits each including two units for selecting and amplifying the reception signal from the antenna 1. , 24 is the antenna 1
A plurality of transmitting circuits each including two units for supplying a transmitting signal to the receiving circuit; 25, a reception intensity comparing and judging circuit for selecting and comparing a system in which the receiving signal is input from the receiving circuit 23 and having a good receiving state; It is a control circuit that switches the switch so that the antenna is selected by the reception diversity comparison / determination circuit 25 and the antenna selected by the reception diversity is used to transmit to the mobile station.

Next, the operation will be described. First, TD
FIG. 3 shows an example of the configuration of the wireless channel in the case of the MA / TDD system. In this example, one uplink / downlink TDM frame is composed of four slots, and if the frequency f ₁ can use all the slots for communication, one frequency can communicate with four mobile stations. For example, if the mobile station (PS) 1 uses slot 2, the mobile station 1 transmits to the base station at slot 2 in the up section and receives from the base station in slot 2 in the down section.

In FIG. 2, one unit of receiving circuits 23 and 1
The transmission circuit 24 of the unit is set as one set, and the antenna 21
Use one. Furthermore, two systems are prepared for reception / transmission diversity. In this system, the signal transmitted from the mobile station in the upstream section is received by the antenna 21, and then supplied to the reception circuit 23 by the transmission / reception changeover switch 22 whose switch is the reception side. At this time, if the system is diversity before detection, the receiving circuit 23
The signal output from the receiving circuit 23 is an F / IF stage circuit and is a signal processed by the RF or IF circuit, and diversity reception is performed using this signal. For pre-detection diversity combining, select combining that selects the received wave with the maximum envelope level, equal gain combining that combines all received waves in phase and then combine as is, and maximum ratio that is combined by weighting with the received wave envelope level There is composition. On the other hand, if the system is diversity after detection, the receiving circuit 23 includes an RF / IF stage circuit to a detector, and performs diversity reception using a signal at the detector output stage of the receiving circuit 23. Post-detection diversity combining includes not only selective combining but also weighting combining using the received wave envelope level.

Further, the reception circuit 23 outputs the reception level to the reception strength comparison / determination circuit 25. The reception strength comparison / determination circuit 25 compares the reception levels of the respective systems, selects the system having the maximum reception level, and outputs it to the control circuit 26. When the control circuit 26 transmits to the mobile station in the downlink section, the control circuit 26 controls the transmission / reception changeover switch 22 and the transmission circuit 24 so that the transmission is performed in the system having the maximum reception level when the immediately preceding slot is received. To do. This state is shown in FIG.

Such a system is introduced, for example, in "Effects of Applying Base Station Antenna Switching Diversity in TDMA / TDD Transmission" in 2-413 of the 1993 Spring Conference of the Institute of Electronics, Information and Communication Engineers.

[0009]

In the above-mentioned system, a transmission circuit of n (the number of selected diversity) units is required for one TDM frame, which increases the scale of the apparatus. Further, n antennas are required for one TDM frame, and when the antenna is installed in a place where there is a lot of traffic, the number of antennas increases, which increases the cost of the base station device and increases the size of the base station device itself. Is expected to occur.

Further, at the beginning, when a small base station is installed for a place with little traffic, and when the number of frames that can be communicated is increased due to an increase in traffic due to the improvement of infrastructure and an increase in the number of subscribers, expansion will occur. There is a problem of difficulty. It is an object of the present invention to construct a base station that can be easily expanded at a low cost with respect to the above problems.

[0011]

In view of the above points, the present invention provides an n-type shared transmission / reception system for executing the diversity system.
A book antenna, and a plurality of receiver circuits each including n units for selecting and amplifying a received signal from the antenna,
A distribution circuit that distributes a reception signal from the antenna to the plurality of reception circuits to share the antenna, a plurality of transmission circuits that form one unit that supplies a transmission signal to the antenna, and the antenna. A radio having a combination circuit for combining transmission signals from a plurality of transmission circuits for sharing, and a transmission antenna changeover switch between the transmission circuit and the combination circuit for switching transmission antennas. It is a base station device of a telephone system.

[0012]

According to the present invention, the distribution circuit for distributing the reception signal from the antenna to the plurality of reception circuits and the combination circuit for combining the transmission signals from the plurality of transmission circuits are provided. Since the transmission antenna changeover switch is connected between them, the configuration is easy to expand.

[0013]

1 is a block diagram showing an embodiment of a base station apparatus of a radio telephone system according to the present invention. In FIG. 1, reference numeral 1 is an antenna for transmitting and receiving radio signals, 2 is a transmission / reception switch for switching between transmission and reception, and 3 is an amplifier for amplifying a received signal from the antenna 1 and evenly distributing it to a plurality of receiving circuits (described later). A distribution amplifier circuit 4 for performing a combination amplification circuit for combining and amplifying signals from a plurality of transmission circuits (described later),
Reference numeral 5 is a reception circuit for selecting and amplifying a reception signal, 6 is a transmission circuit for supplying a transmission signal to the antenna 1, 7 is a transmission antenna changeover switch for changing the signal from the transmission circuit 6 to an arbitrary antenna, and 8 is the above-mentioned Receiving field strength signals from the receiving circuits 5 are received and the receiving field strength comparing and judging circuit judges the system in a good receiving state by comparing the receiving field strength level. 9 is based on the judgment result from the receiving field strength comparing and judging circuit 8. This is a control circuit for controlling the transmission antenna changeover switch 7 and the transmission / reception changeover switch 2 so as to perform transmission with an antenna having a good reception state.

In FIG. 1, the signal received by the antenna 1 is amplified by the distribution / amplification circuit 3 and evenly distributed to each reception circuit 5 for each TDM frame. The receiving operation is performed in each of the system A and the system B, and each receiving circuit 5 processes the input signal and detects the electric field strength of the received signal, and the reception strength comparison / determination circuit 8 receives the electric field strength. Is supplied. The reception strength comparison / judgment circuit 8 compares the signal indicating the electric field strength from the reception circuit of each system for each TDM frame, judges the antenna of the system having a good reception state, and supplies the judgment signal to the control circuit 9. To do. The control circuit 9 supplies a selection signal to the transmission antenna changeover switch 7 so that the antenna is selected based on this determination signal.

The signal output from the transmission circuit 6 is supplied to the corresponding synthesis amplification circuit 4 via the transmission antenna changeover switch 7 and is synthesized with the signal component transmitted from the corresponding antenna. The data is transmitted from the antenna 1 to the mobile station, and the base station performs transmission diversity for the mobile station. Note that this control is performed for each mobile station corresponding to each time slot of the TDM frame, and as a result, the base station switches the transmission antenna for each slot of the TDM frame.

Thus, the operation according to the present invention is achieved. In the present embodiment, the present invention is configured by hardware, but it goes without saying that it is also possible to replace a part of the hardware with software. Absent. Further, in the conventional example of FIG. 2, each time the corresponding TDM frame is increased depending on the traffic volume, two antennas and two units of transmission / reception circuits are added.
A unit transmission circuit and two units reception circuit are sufficient, and the cost on the base station side of the communication system can be reduced.

Needless to say, the present invention can be implemented even if the base station is constructed with antenna switching reception diversity.

[0018]

According to the present invention, a distribution circuit for distributing a reception signal from an antenna to a plurality of reception circuits and a synthesizing circuit for synthesizing transmission signals from a plurality of transmission circuits are provided. Since a transmission antenna changeover switch is connected between and, the transmission diversity can be realized with only one unit of the transmission circuit for one TDM frame, and the number of antennas is minimized, thus reducing the cost of the base station device. It can be measured.

Furthermore, according to the base station apparatus of the present invention, it is possible to easily cope with an increase in the number of wireless channels that can communicate (expansion of base stations) due to an increase in traffic.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

FIG. 3 is a diagram showing a TDM frame.

FIG. 4 is a diagram showing a relationship between slots and antennas.

[Explanation of symbols]

 1, 21 Antennas 2, 22 Transmission / reception changeover switch 3 Distribution amplification circuit 4 Composite amplification circuit 5, 23 Reception circuit 6, 24 Transmission circuit 7 Transmission antenna changeover switch 8, 25 Reception intensity comparison / determination circuit 9, 26 Control circuit

Claims (1)

[Claims] 1. A plurality of n (n is an integer of 2 or more) antennas for both transmission and reception, a plurality of reception circuits each including an n unit for selecting and amplifying a reception signal from the antenna, and the antenna. In order to share the antenna, a distribution circuit that distributes a reception signal from the antenna to the plurality of reception circuits for sharing, and a plurality of transmission circuits that make up one unit that supplies the transmission signal to the antenna as one set In the wireless telephone system, a combination circuit for combining transmission signals from a plurality of transmission circuits, and a transmission antenna changeover switch between the transmission circuit and the combination circuit for switching transmission antennas are provided. Base station device.