JPH0669235B2 - Circuit switching circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a speech path switching circuit in a wireless base station for mobile communication.

[Problems to be Solved by Prior Art and Invention]

Conventionally, a time-division switch circuit that uses a memory element is used for switching between a time-division-multiplexed speech path and a transceiver for speech communication. This switching circuit requires high-speed operation and the switching scale is compared. Since it is relatively large, there is a drawback in that it is disadvantageous in terms of hardware amount and cost to use it for a speech path switching circuit having a small channel switching range.

Therefore, the purpose of this circuit is a digital signal in which wired voice channels are time-division multiplexed, and when radio wave interference is detected in a call transceiver, the radio channel is switched to another call transceiver, Another object of the present invention is to provide an economical circuit that does not use a time division switch circuit in a diversity switching circuit that does not change the time slot in a time division multiplexed signal.

[Means for solving problems]

In order to achieve the above-mentioned object, in the diversity switching circuit as described above, the switching of the communication transmitter / receiver in which interference is detected, that is, the channel switching, is performed by another switch belonging to the same group as the channel in which interference is detected. It is designed to switch to a channel.

That is, according to the present invention, a radio base station in mobile communication for switching a call transceiver provided for frequency with a digital signal in which wired voice is time-division multiplexed to avoid radio wave interference. In the call path of, the plurality of call receivers and call transmitters, which are provided for the plurality of call channels allocated to the radio base station and transmit and receive call signals to and from the mobile station, The received analog signal is sampled at a fixed cycle and quantized, then the value is output to the wired system in response to the reception of the transmitted pulse, and the received pulse is received from the time-division-multiplexed digital signal sent from the wired system. To a plurality of codec circuits for extracting one channel for conversion into an analog signal and outputting it to each call transmitter in synchronization with the reception of And a plurality of channel control circuits each provided with a sync pulse generation circuit for supplying sync pulses for reception, and a group for supplying pulses for generating sync pulses for transmission and reception to the sync pulse generation circuit of the channel control circuit. A call receiver for transmitting / receiving a call signal to / from a mobile station; and a control circuit for controlling a synchronous pulse generating circuit of the channel control circuit to send a command to the synchronization pulse generating circuit of the channel control circuit via a control bus line. When switching the call transmitter within the same radio base station, the call receiver that is transmitting and receiving call signals to and from the mobile station, and the transmission pulse and reception pulse that are being supplied to the call transmitter, and the mobile station The sync pulse so that the transmission pulse and the reception pulse transmitted to the call receiver and the call transmitter for transmitting and receiving the call signal are exchanged. By changing the phase of the sync pulse supplied to the codec circuit circuit within the same group by giving a command to the raw circuit via the control bus line, it is possible to switch the communication transceiver for use. A call path switching circuit characterized by the above is obtained.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of one embodiment of the present invention, which is 1 ₁ to 1
₆ is a call transceiver for channels CH1 to CH6, 2 ₁
Each of the channels ₂₅ to ₂₅ is a channel control circuit for performing analog-to-digital conversion in units of 6 voice lines and further multiplexing and demultiplexing. Further, a is a voice up signal line and b is a down signal line, both of which have an analog voice of 600Ω on the balanced signal line. Reference numerals 3 _{1 to} 36 ₆ are codec circuits (CODECs) for performing encoding and decoding, which sample the analog voice input through the upstream signal line a every 125 μs, quantize it into 8 bits, and output it to the signal line c. The digital audio signal input through the signal line d is converted to analog and output to the signal line.
The signals on the signal line c output from the CODECs 3 ₁ to 36 of the channels CH1 to ₆ are wired-ORed and output to the signal line e, which is connected to the five channel control circuits and the signal line e Upstream audio 30 channels are multiplexed, and the signal transmission rate is 2.048 Mb / s. Further, the signal on the signal line d is the same as 2.048 Mb / s in which 30 channels of downlink voice are multiplexed.

Fig. 2 shows the signal structure on the signal lines d and e. Upstream or downstream voice of 1 channel has 8 times in 1 time slot.
Indicated in bits. Note that F indicates a frame synchronization time slot, and empty indicates an unused time slot.

Returning now to FIG. 1, 4 denotes a sync pulse generating circuit, for transmission to reception operation of the digital signal in the codec circuit 3 ₁ to 3 ₆ (multiplexed) sync pulses and for receiving (separation) of the synchronizing pulse signal Supply on lines f and g, respectively.

FIG. 3 is a diagram showing the phase relationship between the above-mentioned two sync pulses. Each codec circuit 3 _{1 to} 3 ₆ receives the sync pulse for transmission, and outputs the sampled and quantized digital signal for 8 bits. Then, the output is set to high impedance, and the signal on the signal line d is taken in by 8 bits by converting it to an analog signal by receiving the receiving synchronizing pulse. Although the interval t of sync pulses Aitonaru channel has a 125 / 32μ sec in this figure, three channels (3 ₃₎
Since the fourth slot is not used as shown in FIG. 2 (prohibition of use), the interval here is twice the value of t.

Returning to FIG. 1 again, the synchronizing pulse generating circuit 4 is connected to the signal lines h for transmission and i for reception from the group designation circuit in units of 6 channels shown by reference numeral 5, 2
Phase-related synchronization signals shown in FIG. 4 are supplied to the channel control circuits ₁ to ₂₆ . Further, a bus line indicated by j is connected to the synchronization pulse generation circuit 4, and the phase relation of the synchronization pulses supplied to the codec circuits 3 _{1 to} 3 ₆ of CH ₁ to ₆ according to the contents instructed on this bus j. And
The synchronizing pulse shown in FIG. 3 is output on the signal line f or g from the falling point of the signal on the signal line h or i as shown in FIG.

That is, a synchronization signal as shown by a solid line in FIG. 4 is applied to each channel control circuit 2 on the group designation circuit 5 or the signal line h or i.
To the synchronizing pulse generating circuit 4, and in the synchronizing pulse generating circuit, the signal line f is synchronized with the falling point of this synchronizing signal.
And g, the synchronizing pulse shown in FIG. 3 is output. I.e. the synchronizing pulse generating circuit 4 channel control circuit 2 _1,
Fourth synchronizing signal to the channel control circuit 2 ₁ as shown in figure is inputted via the signal line i or h, the codec circuit, as shown in FIG. 3 in synchronization with the falling point of the synchronization point
Synchronizing signal to the 3 _{2-3 6} will be determined at the same phase intervals of 132/32 [mu] s.

When switching the call path for diversity, for example, when a call is made using the call transceiver 1 ₁ of the channel CH1 and the codec circuit 3 ₁ and interference occurs in the wireless section of the corresponding channel. In the following, the channel is switched to another channel in the group to which the channel in which the interference has occurred, for example, channel CH6. Specifically, the synchronization pulse generation circuit 4 is controlled so that the synchronization pulses of the channels CH1 and CH6 are exchanged from the bus j. The synchronizing pulse shown by the broken line in FIG. 3 shows this exchanged one. That is, when the synchronization is designated to another channel, in this case, since the number of channels in one frame is 32, a counter (not shown) that makes one round at 32 is used, and the timing of the pulse generated by this counter and the signal line f or g. By synchronizing with the synchronization signal input to the codec circuit 3 via the, each codec circuit can be designated as another channel. That is, the phase of the synchronization signal input to the codec circuit can be converted by controlling the pulse generation timing of the counter with a command on the control bus line j. This allows you to channel calls without changing time slots.
Can continue through CH6. That is, diversity switching can be performed without using a time division switching circuit.

〔The invention's effect〕

As described above, according to the present invention, since the switching range of the communication path is limited to a single group, the amount of hardware of the communication path switching circuit of the radio base station in mobile communication can be made small and can be economically constructed. There is.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a speech path switching circuit which is an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of voice signals on the signal lines d and e of FIG. 1, and FIG. FIG. 4 is a diagram showing the phase relationship of the synchronizing pulses on the lines f and g, and FIG. 4 is a diagram showing the phase relationship of the synchronizing signals supplied to the channel control circuit. Explanation of symbols: 1 ₁ to ₁₆ are transceivers for CH1 to CH6 calls, 2 ₁
~ 2 ₅ is channel control circuit, 3 ₁ ~ 3 ₆ is codec circuit, 4
Is a synchronous pulse generation circuit, and 5 is a group designation circuit.

Claims (1)

[Claims] 1. A call transmitter / receiver provided in a frequency-corresponding manner with a digital signal in which wired voice is time-division multiplexed.
In a communication path of a radio base station in mobile communication that is switched to avoid radio interference, a plurality of calls that are provided for the plurality of call channels allocated to the radio base station and that send and receive call signals to and from the mobile station. Receiver and call transmitter, and the analog signal received by each call receiver is sampled and quantized at fixed intervals, and then the value is output to the wired system in response to the reception of the transmission pulse, and 1 in synchronization with the reception of the received pulse from the time-division-multiplexed digital signal sent from the system
A plurality of channel control circuits each provided with a plurality of codec circuits for converting into channel-extracted analog signals and outputting them to each call transmitter, and a synchronization pulse generation circuit for supplying transmission and reception synchronization pulses to the plurality of codec circuits; A group designation circuit for supplying a pulse for generating a transmission and reception synchronization pulse to the synchronization pulse generation circuit of the channel control circuit, and a command control bus for the synchronization pulse generation circuit of the channel control circuit And a control means for giving a communication signal between the mobile station and the mobile station when switching between the call receiver and the call transmitter for transmitting and receiving the call signal within the same radio base station. From the transmission pulse and the reception pulse supplied to the call receiver and call transmitter that are transmitting and receiving to the mobile station A codec is provided by giving a command via the control bus line to the synchronous pulse generation circuit so as to replace the transmission pulse and the reception pulse transmitted to the call receiver for transmitting and receiving the call signal and the call transmitter. A speech path switching circuit characterized in that a speech transceiver to be used can be switched by changing the phase of a synchronization pulse supplied to the circuit within the same group.