JPH01194532A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To effectively prevent transmission disturbance to another slave station by automatically prohibiting transmission when a synchronizing signal from a center station can not be received in one slave station. CONSTITUTION:When the synchronizing signal from the center station can not be received in the slave station, a pulse is not outputted from a synchronizing signal detecting circuit 7 and a reset is not loaded to a timing pulse generating circuit 8. Then, a self-running is started and thus, the condition of synchronization dislocation is obtained. When there is no reset pulse from the synchronizing signal detecting circuit 7, the output of a pulse detecting circuit 9 goes to be '0' since the reset pulse is inputted and for the pulse to be outputted from the timing pulse generating circuit 8, a gate is loaded by an AND circuit 6. Thus, a switch 10 is prohibited from being turned on and a transmitter 3 goes to a turning-off condition. Since the transmission is stopped when the synchronizing signal can not be received, the transmission disturbance to the other slave station, for which synchronization is obtained, can be effectively prevented.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a wireless communication device for a slave station used in time division multiple access wireless communication in which there is at least one central station and a plurality of slave stations. .

[Prior Art] Conventionally, in time-division multiple access wireless communication consisting of one central station and multiple slave stations, the slave stations are synchronized frame by frame from the central station, as shown in Figure 2. Signal 12.
13, and this synchronization signal resets the timing pulse generation circuit (circuit that generates the transmission time slot timing signal) to synchronize with the central station.

Based on the synchronized transmission time slot timing signals, the slave stations transmit to the central station using the assigned time slots.

[Problems to be solved] In the conventional time division multiple access wireless communication described above, when the slave station cannot receive the synchronization signal from the central station, the timing pulse generation circuit is not reset, and as a result, , the slave station runs on its own and generates a time slot timing signal, resulting in a time slot timing signal that is out of synchronization with the central station.

In such a case, even if the slave station transmits using its assigned time slot, the central station will not be able to clearly receive the signal from the slave station because the time slot timing signal is different from that of the central station. Or, if other synchronized slave stations were transmitting using adjacent time slots, there was a problem of signal interference.

The present invention has been made to solve these problems, and when a slave station is unable to receive a synchronization signal from the central station, it automatically prohibits transmission and prevents transmission to other slave stations. The purpose of the present invention is to provide a wireless communication device that can effectively prevent interference.

[Means for solving problems] In order to achieve the above object, the present invention detects a synchronization signal sent from a central station in a wireless communication device for a slave station for communicating with a central station using a time division multiple access method. This configuration includes a synchronizing signal detecting means for detecting a synchronizing signal, and a switch means for controlling permission or prohibition of transmission output of the transmitter based on the output of the synchronizing signal detecting means.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a wireless communication device according to this embodiment. Note that this wireless communication device should be installed in a slave station in the previous division multiple access system.

In the drawing, l is an antenna and 2 is a duplexer.

The signal received by antenna 1 is sent to receiver 4, and the transmission output from transmitter 3 is sent to antenna l.

7 is a synchronization signal detection circuit which detects a synchronization signal from the signal demodulated by the receiver a4 and outputs a pulse. Reference numeral 9 denotes a pulse detection circuit which, when detecting a pulse from the synchronizing signal detection circuit 7, outputs "1" during the - frame. 8 is a timing pulse generation circuit which uses the output pulse from the synchronization signal detection circuit 7 as a reset pulse to generate and output a time slot timing signal synchronized with the synchronization signal of the central station.

5 is a data transmission circuit which inputs the timing signal of the time slot assigned by the central office from the timing pulse generation circuit 8, and transmits the data to the transmitter 3 at that timing.
Send to.

10 is a switch for turning on the power to the transmitter 3; 6 is an AND circuit; the switch 10 is controlled by outputs from the timing pulse generation circuit 8 and the pulse detection circuit 9; The AND circuit 6 turns on the switch 10 at the timing output from the timing pulse generation circuit 8 when in a synchronized state, and turns off the switch 10 when the synchronization is off regardless of the output from the timing pulse generation circuit 8. state.

Next, the operation will be explained.

The central station sends a synchronization signal to the slave stations once every -frame. The slave station demodulates this synchronization signal via the antenna 1 and the shared antenna 2 at the receiver 4.

When the synchronization signal detection circuit 7 detects a synchronization signal from the demodulated signal, it outputs a pulse, and the timing pulse generation circuit 8 is reset by this output pulse. This reset pulse causes the timing pulse generation circuit to generate a time slot timing signal synchronized with the synchronization signal of the central station, and use the time slot timing signal to determine the time slot that is assigned to the local station for transmission. Outputs “l”.

At this time, if the slave station is receiving a synchronization signal from the central station, a pulse is output from the synchronization signal detection circuit 7, so the output of the pulse detection circuit 9 is always "L", and the timing pulse The timing signal output from the generation circuit 8 determines the period of time slot 2 to be transmitted,
The output of the AND circuit 6 becomes "L", so the switch 10 is turned on and the power supply 11 is turned on to the transmitter alI3.

As a result, the signal sent out from the data sending circuit 5 is modulated by the transmitter Ja, 3, and the duplexer 2. It is transmitted via antenna 1 to the central station.

On the other hand, when the slave station is unable to receive the synchronization signal from the central station, no pulse is output from the synchronization signal detection circuit 7, the timing pulse generation circuit 8 is no longer reset, and the slave station begins to run by itself. Therefore, a difference occurs between the time slot timing signal transmitted by the slave station and the time slot timing signal of the central station, resulting in an out-of-synchronization state.

Therefore, when there is no reset pulse from the synchronization signal detection circuit 7, the output of the pulse detection circuit 9 becomes "O" because the reset pulse is input.

The pulse output from the timing pulse generation circuit 8 is
A gate is applied by the AND circuit 6, thereby prohibiting the switch 10 from being turned on and turning the transmitter 3 off. In this way, when the synchronization signal cannot be received, transmission is suspended to prevent interference with other slave stations.

[Effects of the Invention] As explained above, according to the present invention, transmission from an out-of-synchronization slave station is prohibited, and transmission from another synchronized slave station using an adjacent time slot is prohibited. In addition to being able to effectively prevent transmission interference.

It is also possible to prevent the central station from receiving data in other time slots and causing confusion in transmission.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wireless communication device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of demodulated data received by a slave station from a central station. l: Antenna 2: Duplexer 3: Transmitter 4: Receiver 5: Data transmission circuit 6: AND circuit 7: Synchronous signal detection circuit 8: Timing pulse generation circuit 9: Pulse detection circuit 10: Power supply to switch l

Claims (1)

[Claims] In a wireless communication device for a slave station for communicating with a central station using a time division multiple access method, a synchronizing signal detecting means for detecting a synchronizing signal sent from the central station, and a transmitter based on the output of the synchronizing signal detecting means. A wireless communication device comprising: switch means for controlling permission or prohibition of transmission output of the wireless communication device.