JPS59224936A - Time division multi-direction multiplex communication device - Google Patents

Abstract

PURPOSE:To prevent increase in branch circuit loss by switching selectively a corresponding antenna among plural antennas in synchronization with the assigned period of a burst signal of each slave station and executing span equalization at each slave station with simple constitution. CONSTITUTION:A master station 1 and plural slave stations 2a-2c constitute a time division multi-direction communication device and the communication is attained in time division between the master station 1 and the slave stations 2a-2c by using a radio burst signal having the same frequency. An antenna switching control section 8 connected to a transmission/reception section 6 and an antenna switching device 7 of the master station 1 controls the switching device in synchronization with the assigned period of the burst signal to change over antennas 3a-3c of the master station. This switching device consists of an antenna changeover switch 9a operated in interlocking with an output of the control section 8, a transmission fixed attenuator changeover switch 9b and a reception fixed attenuator changeover switch 9c, and an output of the switches 9b, 9c is connected to a circulator 12 via transmission and reception fixed attenuators 10, 11. Further, the circulator 12 is connected to the antennas 3a-3c via the switch 9a to simplify the constitution of the communication device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a time division multidirectional multiplex communication device (hereinafter abbreviated as TDMA device) that performs time-division communication between a master station and a plurality of slave stations using radio burst signals of the same frequency. ) In particular, this article relates to a TDMA device in which when a plurality of antennas are installed at a master station in a TDMA device, an antenna switching device is introduced to switch to the corresponding antenna.

TDMA is a method in which radio waves of the same frequency are time-divided and used by multiple slave stations.In the case of ground-line-of-sight wireless communication, a master station and multiple slave stations are connected by time-division wireless burst signals. It is.

As shown in FIG.
When antennas 3 are scattered over a wide angle, multiple antennas 3 are connected to the master station 1.
(3a to 3c) will be installed to respond.

Hereinafter, according to FIG. 1, as an example, the number of slave stations is 4. The explanation will be made assuming that the number of antennas at the master station is 3. In this case, conventionally, a hybrid or directional coupler has been used for the main station antenna branch, which has caused the following problems.

(4) The antenna branch circuit loss was large, so the transmission power and antenna were increased to compensate for this loss.

(b) Span equalization for each slave station is difficult, and adding a span equalization function requires more hybrids or directional couplers, resulting in even greater branch circuit loss. .

(c), each antenna 3a to 3ct2 provided in the master station 1;
Unnecessary radio waves were being transmitted at times other than those allocated to slave stations 2a to 2d (see Figures 2 (a) and (b) for details).
.

The present invention has been made in view of the above-mentioned conventional circumstances.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a new TDMA device that eliminates the above-mentioned drawbacks by using an antenna switch.

In order to achieve the above object, the TDMA device according to the present invention is a time division multidirectional multiplex communication device that performs time division communication between a master station and a plurality of slave stations using radio burst signals of the same frequency. When a plurality of antennas are installed, the antenna is configured to select and switch the corresponding antenna from among the plurality of antennas in a time-sharing manner in synchronization with the burst signal allocation period with each slave station.

Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of a device according to the present invention provided in the master station 1. As shown in FIG. In the figure, reference number 5 indicates a TDMA logic processing section, and the TDMA logic processing section 5 is connected to an antenna switching section 7 via a transmitting/receiving section 6. Further, the output of the TDMA logic processing section 5 is connected to the antenna switching section 7 via an antenna switching control section 8 that controls the antenna switching section 7 .

The antenna switching section 7 is connected to antennas 3a, 3b, and 3c.

FIG. 4 is a detailed configuration diagram of this antenna switching section 7. The antenna switching section 7 surrounded by a dashed line in FIG.
Three changeover switches completely linked by the antenna changeover control unit 8, namely, the antenna changeover switch 911, the fixed transmitting attenuator changeover switch 9b, and the fixed receive attenuator changeover switch 9C, and the plurality of fixed transmitting attenuators 10 and the fixed receiving attenuator It is composed of a container 11 and a circulator 12.

Next, an outline of the operation of the apparatus having such a configuration will be explained. As shown in FIG. 3, when transmitting 9, the TDMA logic processing unit 5 forms a signal train in the form of a burst, and the carrier wave modulated by the signal train in the transmitting unit of the transmitting/receiving unit 6 is sent to the antenna switching unit 7. be guided. Also, 'I'DMA
An antenna switching control section 8 connected to the logic processing section 5 switches the three switches of the antenna switching section 7 (antenna switching switch 9a, transmitting fixed attenuator switching switch 9b, receiving fixed attenuator) in synchronization with the burst signal allocation cycle. Changeover switch 9
c) is controlled. This selects the desired transmit fixed attenuator 10 and antenna, and the carrier for the transmission is set to 7yr.
It is transmitted in bursts to N slave stations.

- The same is true when the master station 1 receives radio waves from the slave station 2 (28 to 2d), and the slave station is set so that the waves arrive at the same time as the burst-like transmission waves to the desired slave station. The burst-shaped received wave from
(The time chart is shown in FIG. 5).

As described above, according to the present invention, when a plurality of antennas are installed in a master station, by using an antenna switching device, the antennas in the direction of a desired slave station can be switched in synchronization with the allocation of bursts to slave stations. By selecting fixed transmit and receive attenuators,
The disadvantages of using conventional hybrid or directional couplers can be overcome. (a) In a branch circuit using a hybrid or directional coupler, the branch circuit loss increases in proportion to the number of antennas, but with the antenna switching device according to the present invention, the desired antenna can be directly connected by switch operation. Because of the connection, the loss is small, and even if the number of branches increases, the loss will hardly change.

(b) By using a transmission and reception selector switch, the loss is reduced due to the same reason as (4) above.
Furthermore, the amount of fixed transmitting and receiving attenuators for each slave station can be easily set.

(c) Since antennas other than the desired antenna are separated from the radio by the antenna selector switch, unnecessary radio waves can be prevented from being transmitted.

As described above, effects superior to those of the present invention can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a general TDMA device when multiple antennas are installed in a master station, Fig. 2 is a time chart of a conventional system, and Fig. 3 is an example of a TDM & device according to the present invention. FIG. 4 is a specific circuit diagram of the main parts of the present invention, and FIG. 5 is a diagram showing a time chart of the present invention. 1ees master station, 2B~2d*e a slave station, 3a-3C
@...Master station antenna, 4a-4d...O slave station antenna,
5. TDMA logic processing section, 6. Fist transmitting/receiving section, 7
11- antenna switching device, 8@... antenna switching control unit, 9
a--Antenna selector switch, 9b@... Fixed transmitting attenuator selector switch, 9C... Fixed receiving attenuator selector switch, 10... Fixed transmitting attenuator, 11... Fixed receiving attenuator, 12- ...Circulator patent applicant NEC Corporation Representative Patent attorney Yutabe Kumagai-,7-- 173-

Claims (1)

[Claims] When multiple antennas are installed in a time-division multidirectional multiplex communication device that communicates between a master station and multiple slave stations in a time-division manner using wireless burst signals of the same frequency, the burst signal with each slave station is 1. A time division multi-directional multiplex communication device, characterized in that it is configured to time-divisionally select and switch over a corresponding antenna from a plurality of antennas in synchronization with the allocation cycle of.