JPS60250736A - Multi-direction time division radio communication system - Google Patents

Abstract

PURPOSE:To simplify the constitution of a local office, to assign and control channels on the base station side and to utilize efficiently the titled system by using a repeater station having a time division radio line and setting up the number of channels between the base station and the repeater station smaller than that between the repeater station and the local station. CONSTITUTION:Balanched repeater stations 3a-3d for the base station BS2 connected by a PCM line are formed in a switchboard LS1 for a public telephone network and plural local stations 4a1-4d12 corresponding to respective repeater stations 3a-3d are formed. Subscribers 5a11-5d122 are connected to the respective local stations 4a1-4d12 to constitute a multi-direction time division radio communication system. Transmission/reception parts 11, 12 are controlled by a channel separation part 14 in the respective repeater stations 3a-3d. An insertion control part 17 is controlled by a separation control part 15 and a synchronization detecting part 16 and a channel insertion part 16 is controlled by the control part 17. The number of channels between the repeater stations 3a-3d is set up smaller than that between the base station and the repeater stations 3a- 3d to simplify the constitution of the respective local stations 4a1-4d12.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a multicast system that includes a base station, a plurality of branch relay stations, and a plurality of slave stations, and connects the base station and each slave station via a time-division radio link. The present invention relates to a directional time-division wireless communication system.

PRIOR ART AND PROBLEMS A subscriber line wireless communication system is known in which wireless lines are provided for some subscribers in remote locations from an exchange to eliminate telephoneless areas. This subscriber line wireless communication system establishes a wireless line between a base station connected to a switching center of the public telephone network and multiple slave stations or between multiple slave stations via a relay station. Each slave station is equipped with a transmitting/receiving device, and
It accommodates one or more subscribers by wire or wireless, selects channels based on control information from the base station, and establishes communication paths with the subscribers accommodated in the slave stations.

Therefore, since there is no need to lay long-distance telephone cables even in areas very far away from urban areas, a telephone network can be installed at low equipment costs.

However, when using an analog single channel wireless system for communication between a base station and a slave station, each slave station that accommodates multiple subscribers is equipped with multiple transmitting and receiving devices. , equipment costs were high.

On the other hand, with digitalization, it has been considered to establish a time-division radio line and perform communication using a single transmitter/receiver, and recent advances in LSI have made it possible to realize this economically. For example, it is easy to set up a 30-channel time-division wireless line, but each slave station and relay station must also be equipped with a transmitting and receiving device to connect to the 30-channel time-division wireless line. The drawback is that the configuration of the relay station is complicated and expensive. That is, even if the system is simply digitalized, there is a drawback that it is not possible to economically construct a slave station with a small call volume.

Purpose of the Invention The present invention utilizes a relay station of a time-division wireless line, and sets the number of channels between the relay station and slave stations to be smaller than the number of channels between the base station and the relay station. The purpose of this system is to provide an economical configuration of the slave station, and to perform channel allocation and control of the entire system at the base station, thereby achieving efficient operation.

Structure of the Invention In order to achieve the above object, the present invention sets up a time division radio link between a base station and a plurality of branch relay stations, and also establishes a time division radio link between each branch relay station and a plurality of slave stations. In a multi-directional time-division wireless communication system in which divided radio circuits are respectively set, a channel separation/insertion section is provided at each of the branching relay stations, and the channel separation/insertion section divides the time between the base station and the branching relay station. The number of channels of the time-division radio link between the branch relay station and the slave station is set to be smaller than the number of channels of the branch relay station and the slave station, and the number of channels of the branch relay station and the slave station are By changing the number of channels between stations, efficient operation becomes possible. Examples will be described in detail below.

Embodiment of the Invention FIG. 1 is a block diagram of an embodiment of the present invention, in which four branches are connected to a base station (BS) 2 connected to a switching center (LS) 1 of a public telephone network by a PCM line. Relay station (SBS)
32 to 3d, and one for each branch relay station 3a to 3d.
2 slave stations 4al~4a12, 4bl~4b12.4c
1~4c12.4dl~4d12 are provided, and each slave station has an arbitrary number of subscribers 5a11~5a13. ...5a12
1-5a124. ...5d122 is connected by wire or wirelessly.

The switching center 1 and the base station 2 are connected by a PCM 30-channel line, the base station 2 and the branch relay stations 3a to 3d are connected by a 30-channel time-division wireless line, and each branch relay station 3a ~3d and each slave station are connected by time-division radio lines with fewer than 30 channels. For example, each slave station is equipped with a device capable of transmitting and receiving 10 channels, and based on control information from the base station 2, a 10-channel time-division wireless link is established between branch relay station 3a and the slave station, and branch relay station 3b
A 10-channel time-division radio circuit is set between the branch relay station 3C and the slave station, and a 5-channel time-division radio circuit is set between the branch relay station 3C and the slave station, and between the branch relay station 3d and the slave station. Channel allocation can be performed so that there are 30 channels in total.

In this case, the branching relay stations 3a and 3b separate and insert call signals of the designated 10 channels from the 30 channels of the time-division radio link with the base station 2, and the branching relay stations 3c and 3d From the 30 channels of the time-division radio link between the base station 2 and the base station 2, the call signals of the designated 5 channels are inserted into 5 separate channels. That is, each branch relay station 3a to 3d is provided with a channel separation/insertion section. Then, by traffic monitoring at base station 2 or by a request from the branching relay station, the number of channels allocated to the branching relay station accommodating the slave station whose call volume has increased is increased; Control is performed to reduce the number of channels allocated to a branching relay station that accommodates a slave station whose transmission rate has decreased.

Channel allocation control can be performed completely randomly for each call origination, but by determining the basic number of channels and allocating this in a fixed manner, the channel allocation control can be performed in accordance with the call volume.
can also be changed. Therefore, by dynamically allocating channels, efficient operation becomes possible.

The number of installed branch relay stations and slave stations connected to the branch relay station is based on the total call volume of each slave station during the busiest time for the entire system (30
The call volume can be freely selected as long as it is within the amount of calls that can be handled by the channel (channel) with an allowable call loss rate. That is, in the case of 30 channels, if the allowable call loss rate is 10%, the processing call volume is 27 erlangs, and if the average call volume per slave station is a erlang, it is possible to install 27/a slave stations in the entire system. can be,
This can be connected to the base station via an appropriate number of branch relay stations.

The configuration shown in Figure 1 shows the case where the traffic volume of the slave station is 0.6 Erlang, the number of branching relay stations is 4, the number of channels per branching relay station is 10, and the number of slave stations is 12. It shows. It also includes a case where the switching center 1, the base station 2, and the branch relay station are installed in the same premises, and in such a case, the base station and the branch relay station are connected by wire. Furthermore, wireless relay stations can be provided between the base station and the branch relay station and between the branch relay station and the slave stations, as required.

The base station 2 detects call occurrence and allocates channels.

It is equipped with the functions of a radio telephone base station, such as call termination detection, subscriber call control, and transfer of called party information to the switching center 1, and can be realized with a known configuration.

FIG. 2 is a block diagram of main parts of the branching relay station according to the embodiment of the present invention, in which 11 is a transmitting/receiving unit that transmits and receives data to and from the base station 2, 12 is a transmitting and receiving unit that transmits and receives data to and from each slave station, 13 is a synchronization detection unit, 14 is a channel separation unit, 15 is a separation control unit,
16 is a channel insertion section, and 17 is an insertion control section. The transmitter/receiver 11 transmits and receives time-division radio channels of, for example, 30 channels to and from the base station 2, and the transmitter/receiver 12
The terminal transmits and receives, for example, 10 channels of time-division radio lines to and from each slave station.

The signal received and demodulated by the transmitter/receiver 11 is sent to the synchronization detector 13
A frame synchronization signal is detected by the synchronization detection section 13, and the synchronization signal is applied to the separation control section 15 and the insertion control section 17. The channel separation unit 14 also includes a memory (not shown) having a storage capacity for one frame of signals transmitted from the base station 2, and the writing and reading thereof are controlled by the separation control unit 15. The channel signals are read out, a frame is constructed, and the frame is sent from the transmitting/receiving section 12 to each slave station.

The channel insertion unit 16 also includes a memory (not shown) having a storage capacity for one frame of signals made up of signals sent from each slave station at designated timings,
Writing and reading are controlled by the insertion control unit 17, and after reading at a designated timing, a frame is formed and sent from the transmitting/receiving unit 11 to the base station 2. 3 is a block diagram of the main parts of the slave station according to the embodiment of the present invention, 21 is a transmitting/receiving section, 22 is a slave station control section, 23 is a demultiplexing section, 24+ to 24, 1 are buffer memories (BF ),
251-2511 are DA converters (D/A), 26I-2
67 is a hybrid circuit (H), 27+ to 277 are subscribers connected by subscriber lines, 281 to 28. l is an AD converter (A/D), 29, to 29, 1 is a buffer memory (
BF), 30 is a multiplexing unit. The slave station control unit 22 detects the frame synchronization signal sent from the branch relay station, performs frame synchronization, extracts a control signal, controls the demultiplexer 23, and sends the signal to the subscriber accommodated in the white station. The divided signals are separated and stored in the buffer memory 24+ (t=L 2+ ・”
n), it is converted into an analog signal by the DA converter 255 and sent to the subscriber 27! via the hybrid circuit 26N.
Send to.

Also, the voice signal from the subscriber 27 is sent to the hybrid circuit 2.
6+ to the AD converter 28t, converted into a digital signal, temporarily stored in the buffer memory 29i, multiplexed in a predetermined time slot by the multiplexer 30, and sent from the transmitter/receiver 21 to the branch relay station. Ru.

The slave station control unit 22 uses a control signal from the branch relay station to
The device identifies the channel assigned to the Shiroko station and controls demultiplexing and multiplexing.Changes in the assigned channel can also be easily identified, making it easy to change channel assignments in response to call volume. can be dealt with.

Further, although the case where the subscriber 27i is connected via a subscriber line is shown, it is also possible to connect wirelessly, and in this case,
It is possible to use an FM signal of a predetermined frequency.

FIG. 4 is an explanatory diagram of an example of a frame format (al is 3 between the base station 2 and branch relay stations 3a to 3d).
0 channel time division wireless line, F is a frame synchronization signal, C is a control signal, and T1 to T30 are 30
This is the channel call signal. In addition, (b) is the branch relay station 3
The frame structure is shown in the case of 10 channels between a to 3d and each slave station, where Fa is a frame synchronization signal, Ca is a control signal, and t1 to tlo are communication signals of 10 channels. When the signal shown in fa) is sent from the base station 2, the synchronization detection circuit 13 detects the frame synchronization signal F in the branch relay stations 3a to 3d, and frame synchronization is established. A synchronization signal is applied to the insertion control section 17.

Further, the control signal C includes channel number information 9 assigned to each branch relay station, calling information, dialing information, etc., and is extracted by the separation control section I5.

In accordance with this control signal C, the separation control unit 15 controls the writing of one frame into the memory of the channel separation unit 14, and also reads each call signal from the communication control unit 12 of the channel number assigned to the own branch relay station. Send to slave station.

The control signal Ca includes information on the slave station in which the called subscriber is accommodated, channel designation information, etc. The signal received and demodulated by the transmitter/receiver 21 of the slave station is synchronized by the slave station controller 22. The control signal Ca is extracted, and the call signal of the channel number addressed to the Shiroko station is demultiplexed by the demultiplexer 23, converted into an analog call signal, and sent to the subscriber.

Also, the call signal from the subscriber is digitized by an AD converter, multiplexed in a time slot specified by the control of the slave station control unit 22 in the multiplexing unit 30, and sent from the transmitting/receiving unit 21 to the branching relay station. Sent out.

When the transmitter/receiver 12 of the branching relay station receives a signal from each slave station, it is temporarily written into the memory of the channel inserter 16, and then read out under the control of the inserter controller 17 so as to be inserted into a designated time slot. and is transmitted to the base station 2 via the transmitting/receiving section 11.

For example, channel assignment to branch relay stations 3a to 3d is
The branch relay station 3a has 10 channels T1 to TIO, the branch relay station 3b has 10 channels T11 to T20, the branch relay station 3C has 5 channels T21 to T25, and the branch relay station 3d has 5 channels T26 to T30. In the case of 5 channels, between the branching relay station 3''a and the slave stations 4al to 4a12, in the frame shown in (bl in FIG. 4), T1 to TIO correspond to channels t1 to tlO, and the branching Between relay station 3b and slave stations 4bl to 4b12, T11 to T20 are tl
- Corresponding to the tlO channel, branch relay station 3c and slave station 4
Between C1 and C12, T21 to T25 are t1 to tl of the frame in FIG. 4(b).

(the other 5 time slots are empty), and branch relay station 3d and slave station 4dl.
~4d12, T26~T30 is t1~tlO
This corresponds to any five time slots among them.

Then, by traffic monitoring at the base station 2, for example, if the traffic volume of the slave station via the branching relay station 3a is small (or vice versa), if the traffic volume of the slave station via the branching relay station 3d is large (or , the control signal C from the base station 2 reduces the number of channels allocated to the branching relay station 3a (and increases the number of channels allocated to the branching relay station 3d), thereby preventing an increase in the call loss rate of the slave station via the branching relay station 3d. This can be prevented.

Furthermore, although the above-mentioned embodiments are based on a subscriber line wireless communication system, the present invention is not limited to such a subscriber line wireless communication system. The present invention can be applied to various systems that perform relay communication with slave stations.

As described in detail, the present invention provides each branch relay station 3a to 3d.
, a channel separation section 14. A channel separation and insertion section consisting of a channel insertion section 16 and the like is provided, and the channel separation and insertion section uses the channel separation and insertion section to determine the time between the branching relay station and the slave station based on the number of channels of the time division radio link between the base station and the branching relay station. The number of channels on the split wireless line is set to a small number, and the number of channels between the branch relay station and the slave station is changed according to the traffic volume of the slave station, so that each slave station can cope with the small number of channels. Therefore, the transmission speed can be reduced, and
Since the power consumption can be reduced and the configuration is relatively simple, it is possible to save money. Furthermore, since it is possible to dynamically change the channel allocation of the branching relay station, efficient operation is possible in response to the traffic volume.

Also, by providing a channel separation/insertion section in a branching relay station, the cost will be higher than that of a simple relay station, but the channel separation/insertion section has a relatively simple configuration and can be used to economically configure a large number of slave stations. Since the advantage of being able to do this is great, the system as a whole can be made more economical.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a main part of a branch relay station of an embodiment of the present invention, and FIG. 3 is a block diagram of a main part of a slave station of an embodiment of the present invention. FIG. 4 is an explanatory diagram of an example of a frame format. 1 is the switching center (LS), 2 is the base station (BS), 3a~
3d is branch relay station (SBS), 4a 1~4a and 12.4bl~4b12, 4cl~4c12, 4dl~
4d12 is a slave station, 5all, =-・5d122 is a subscriber, 11.12 is a transmission/reception unit, 13 is a synchronization detection unit, 14 is a channel separation unit, 15 is a separation control unit, 16 is a channel insertion unit, and 17 is an insertion control unit. Department. 111, ``! dl Figure 2 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A multidirectional time-division wireless communication system in which time-division wireless lines are set up between a base station and multiple branching relay stations, and time-division wireless lines are set up between each branching relay station and multiple slave stations. A channel separation/insertion unit is provided in each branching relay station, and the channel separation/insertion unit separates the branching relay station from the slave station based on the number of channels of a time-division radio link between the base station and the branching relay station. The number of channels of a time-division radio link between the branch relay station and the slave station is set to a small number, and the number of channels between the branch relay station and the slave station is changed in accordance with the traffic volume of the slave station. Directional time division wireless communication system.