JPS58151738A - Multidirectional multiplex radio synchronization method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a 9 time division multidirectional multiplex radio synchronization system.

When performing wireless communication using a plurality of fixed communication paths between one point and a plurality of points, it is desirable to use a pair of radio waves from the standpoint of effective use of radio waves.

As a specific method, conventionally, a fixed frequency band is used by frequency division for each direction. A so-called frequency division multiplexing radio system has been used in the past. However, with the recent development of digital communication technology, time division multidirectional multiplexing systems using digital communication systems are being studied and are about to be put into practical use.

Time-division multidirectional multiplexing is a method that performs time-division communication between one central station (hereinafter referred to as the master station) and multiple opposing stations (hereinafter referred to as slave stations), and uses radio waves. The most effective way to use this is to transmit radio waves continuously from the master station to the slave stations, and to transmit radio waves from the slave station to the master station in a manner that matches the time slots assigned to each slave station in advance. One possible method is to send out radio waves intermittently at the same timing. In such a case, the slave station synchronizes the transmission speed of the signal Φ← from the slave station to the master station with the speed of the signal that is also transmitted from the master station, and the slave station transmits radio waves from the master station to the slave station. If the master station transmits a synchronization signal (hereinafter referred to as a frame synchronization signal) that transmits the timing of transmission by including it in the signal toward the slave station, the synchronization signal can be included in the signal sent by the slave station. There is no need for transmission. FIG. 1 shows the timing of transmitting codes in this system.

The format of the code to be transmitted using this system must be based on the transmission of a baseband code for PCM communication, considering the transmission of audio signals. When transmitting baseband codes for PCM communication, there is no particular problem in the direction from the master station to the slave station (hereinafter referred to as the downlink direction), but there is one intermittent transmission in the direction from the slave station to the master station (hereinafter referred to as the uplink direction). The transmission period (T in FIG. 1) is the repetition period of the frame structure of the PCM communication method, which is 12. Sμ; must be selected as an integral multiple of see. If the repetition period is large, the number of codes transmitted at one time is also large, and the slave station must memorize the codes transmitted at one time until it is transmitted, and the master station must remember the codes transmitted at one time. ,
It is necessary to store the codes of each slave station until they are complete for one cycle. For this reason, it is most economical to select an uplink transmission cycle of 125 μs for a two-time division multiplex radio device.

On the other hand, in the PCM communication method of the Sae channel method, 125μSe
In addition to the C-length frame, 12 frames make up the multi-frame, especially this multi-frame A.
The 6th frame and the 12th frame [l is.

The dial pulse signal is transmitted by changing part of the code structure. They are doing what is called pit stilling. Therefore, if the multiframe is not transmitted correctly, the uplink dial pulse signal will not be transmitted.

In order to solve the above problems, the transmission period of the slave station should be increased by 6 times or even 12 times of 125 μsec.
In this case, a storage device for 6 frames or 12 frames is required for each of the master station and slave station.

The system cannot be constructed economically. Also, it would be better to create a PCM terminal equipment that can control the PCM terminal equipment side from the radio equipment side and send out frames that have undergone pinot stealing when necessary, but it is necessary to create a PCM terminal equipment that is 9% unique. It cannot be said that it is economical to construct a PCM terminal station.

The present invention aims to solve two or more problems and provide an economical wireless transmitting and receiving device that uses standard PCM terminal stations and requires as little storage capacity as possible. .

The present invention inserts a frame synchronization signal every 125 μsec in the downstream code string, inserts a frame synchronization signal with the same pattern every 6 frames, and in each slave station, a pit step is performed every 6 frames. By transmitting a frame that has undergone Ealing.

The main technical focus of the master station is to be able to configure the device without having to own a storage device for many frames.

FIG. 2 ta) is an example of the frame structure in the downstream direction of the present invention, where F is a frame synchronization pit, S is a PCM signal,
This is a signal pit that includes service channel signals, control signals, etc. FIG. 2 tb) shows an example of the F bit pattern shown in FIG. 2 ta). By transmitting codes in the master station using the fatO frame structure shown in FIG.
It is possible to detect the timing at which a pit-stalled code should be transmitted for each frame.

FIG. 3 is a block diagram of a master station in nine embodiments of the present invention;
is a PCM terminal device, 2 is a transmission speed conversion circuit, 3 is a radio transmitter, 4 is an antenna common circuit, 5 is an antenna, 6 is a radio receiver, and 7 is a reception speed conversion circuit.

8 is a clock generation circuit.

FIG. 4 is a slave station block diagram of an embodiment of the present invention;
is an antenna, 12 is an antenna common circuit, 13 is a wireless reception machine,
13 is a frame synchronization detection circuit, 15 is a speed modulation circuit, 1
Reference numeral 6 designates a PCM terminal station device, 17 a frame synchronization circuit for outputting the PCM terminal station, 18 a transmission storage circuit, 19 a clock distribution circuit, 20 a radio transmitter, and 21 a transmission switch.

Next, in this operation, the PCM terminal station output signal shown in FIG. added.

The transmission speed of the pulse is converted and modulated by the radio transmitter 3,
Aerial duplexer 4. The signal is transmitted to the slave station via the antenna 5.

On the slave station side, the signal is received by the antenna 11 shown in FIG. 4, and guided to the receiver 13 via the antenna sharing device 12, where it is received and demodulated. The frame synchronization detection circuit 14 detects the frame synchronization signal added by the master station from the demodulated signal.
The data transmission timing for each sec and the timing to transmit the pinot stealing code are detected, and the reception speed conversion circuit converts the service channel signal, PCM
The signal, control signal, etc. are separated and the PCM signal is guided to the PCM terminal device 16. In the operation from the slave station to the master station, as shown in FIG. 4, the frame synchronization signal and multi-frame signal from the PCM terminal station are detected by the frame synchronization detection circuit 17 of the terminal station. On the other hand, the output from the PCM terminal station is sent to a storage device consisting of 18-1''-48 x 6 in the transmission storage circuit 18 for each frame.

The signal of the communication path assigned to the corresponding slave station is stored for each frame, and any of the storage devices 18-1 to 18-6, for example, the sixth storage device 18-6, stores the signal of the communication path assigned to the corresponding slave station. The signal of the frame in which the process was performed is stored. The contents stored in the storage circuit 18 are sent to the wireless transmitter 20 in accordance with the data sending timing detected by the frame synchronization signal detection circuit 14 of the master station and the data sending timing of the bit-staying frame. Ru.

The radio transmitter output is connected to the antenna duplexer 12 by the transmitting switch 21 only during the period assigned to the own station, and the output is transmitted to the antenna 1.
1 to the master station. At the master station, the signal is received by the antenna 5 shown in FIG.
The PCM signal is received by the speed conversion circuit 7, and only the PCM signal is sent to the PCM terminal station 1, excluding the time for the service channel, control signal, guard time, etc.

In the above embodiment, the code of the service channel, the supervisory control signal, the guard bits used to remove code interference at the master station when transmitted by each slave station, etc. are not particularly related to the present invention, so their descriptions are omitted. did.

Further, in the description of the PCM terminal station, the number of communication paths was not specifically specified, but the number of nine communication paths is not particularly related to the present invention, so the explanation is omitted.

As explained above, according to the present invention, in a time division multidirectional multiplexing system that transmits a signal obtained by converting audio into a PCM code as a main signal, a standard PCM terminal station device is used and the required storage is It is possible to obtain a transmitting/receiving device with minimum capacity.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the transmission timing of the 9 time division multidirectional multiplexing system, FIG. 2 is an example of the structure of a frame synchronization signal from the master station to the slave station of the present invention, and FIG. An example of the configuration of a master station, and FIG. 4 is an example of the configuration of a slave station according to the present invention. 1: PCM terminal device, 3: wireless transmitter, 18: memory circuit. Figure 1 Figure 2 (Q) Figure 2 (b) Figure 3 Figure 4

Claims (1)

[Claims] In the case of wireless communication between a central station (master station) and a plurality of stations facing it (slave stations), a digital modulation method is used as the wireless modulation method. , a wireless communication system that transmits a pulse code modulation (PCM) signal as one of the transmitted codes, uses a pair of transmitting and receiving frequencies, and transmits in 9 time divisions in each direction. At. A frame synchronization signal is inserted every 125 μs into the code sent from the master station to the slave station, and the frame synchronization signal is detected by the slave station so that the same code is sent every 6 frames. Then, every 125 μS, the code is transmitted to the master station in the time slot assigned to the local station, and the code belonging to the local station is transmitted to the master station.
The code for transmitting the dial pulse is detected from the signal transmitted from the CM terminal equipment, and the break in the frame synchronization pattern of every 6 frames is detected so that the two are at a constant time interval. A synchronization method of time division multidirectional multiplexing characterized in that the master station combines the codes of each slave station without temporarily storing them by transmitting them to the master station.