JP2871504B2 - Multi-way multiplex communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-directional multiplex communication system in which communication is controlled by a demand assignment system in which a time slot is allocated between a slave station and a master station only when a call is generated in the slave station. It is about.

[0002]

2. Description of the Related Art In general, a multi-directional multiplex communication system of this type has a one-to-N ratio between one master station and a plurality of slave stations which are geographically separated and are scattered around the master station. Is configured to perform communication. Such a system is described in, for example,
This is disclosed in Japanese Patent Application Laid-Open No. 9-2454, which discloses a method of transmitting predetermined communication information from a master station to each slave station using a time division multiplexing (TDM) method. Information is transmitted, and each slave station separates and selects communication information for itself and extracts it. On the other hand, for transmission of communication information in the uplink direction from each slave station to the master station, time division multiple access in which each slave station transmits a transmission burst signal only within a predetermined time slot allocated to the own station. Using the (TDMA) method, predetermined communication information is transmitted to the master station, and the master station separates and extracts communication information from each slave station, thereby performing two-way communication.

FIG. 6 shows an example of the configuration of such a system. An exchange 1 to which a wired terminal such as a telephone is connected is connected to a radio transceiver 4 via a control unit 3 and a slave station 5-.
1 to 5-n are connected to the radio transceiver 4 by a multi-directional multiplex radio line. The exchange 1 is connected to a plurality of wired terminals represented by telephones, and exchanges and connects calls from the terminals. An exchange-connected signal is transmitted through a wireless transmission path. Since the number of channels in the wireless transmission path is generally smaller than the number of connection destinations that can be exchange-connected, the number of exchange-connectable lines is limited to the number of channels in the wireless transmission path. , Ie, concentrating. The control device 3 performs TDMA control after performing the line consolidation process, and performs wireless transmission to the slave station via the wireless transceiver 4. The downlink information from the radio transceiver 4 to the slave stations 5-1 to 5-n broadcasts the same information to all slave stations, and the transmission capacity also takes into account the traffic volume at the peak time of all slave stations. It has a capacity that is. On the other hand, in the upstream direction from each slave station to the master station, a so-called burst signal is sent, when necessary, to send a signal to a time slot assigned to the slave station.

[0004]

However, in such a system, if there is another radio system near a line on a certain route, interference may occur depending on the frequency used, and in this case, the system may be affected by the interference. Only the line may be unavailable. For this reason, for example, it is conceivable to connect only the line in that direction by a wired transmission line to avoid interference from other wireless systems. In this case, since the wired transmission line to be laid is provided in place of the wireless transmission line, a cable having the same standard as the wireless transmission line is required. However, since the wired transmission path does not transmit signals to a large number of paths as in the case of a wireless transmission path, it is only necessary to transmit a signal to a certain path. In spite of the fact that it requires only a small number of functions, it has a problem that it is required to have the same standard function as that of the wireless transmission path, resulting in poor economy. The present invention has been made in view of such a situation, and an economical transmission line that transmits only to a part of the routes can be used.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a transmission speed of a predetermined route among multidirectional routes from a master station to a slave station is set to be higher than that of the multidirectional route. The transmission speed is converted to a low transmission speed, and the transmission is performed on a transmission line different from the multi-directional route. According to a second aspect of the present invention, in the first aspect of the present invention, information of a slave station number and a time slot number is added to a time slot assigned to each slave station, and a route from the master station to the slave station is determined based on this information. It was made. According to a third aspect of the present invention, in the first aspect of the present invention, information of a slave station number and a time slot number is added to a time slot used by each slave station, and this information is used to multiplex a time slot from a slave station to a master station. Is controlled.

[0006]

According to the first aspect of the present invention, the transmission lines of the routes having different transmission speeds are incorporated in the multi-directional multiplex system as transmission lines independent of the multi-directional transmission line. According to the second aspect of the present invention, a route from the master station to the slave station whose transmission speed has been changed is determined based on the slave station number added to the time slot and the time slot number. According to the third aspect of the present invention, the multiplex position of the slave station whose transmission speed received by the master station has been changed is determined based on the slave station number and the time slot number added to the time slot.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention. The same parts as those in FIG. In this example, information transmission to a predetermined route uses a wire transmission line 14 having a capacity suitable for the traffic volume of the route, and a signal transmitted from the control device 3 The transmission rate is converted to a transmission rate suitable for the capacity, and is transmitted from the wired transceivers 13-1 to 13-n. In order to convert such a transmission speed, the wired transceivers 13-1 to 13-n perform frame conversion, and can transmit the converted signal to the wired transmission path 14. Similarly, the wired slave stations 10-1 to 10-n also have a speed conversion function adapted to the transmission speed of the wired transceivers 13-1 to 13-n.

FIG. 2 shows details of a main part of FIG.
The control device 3 includes a control unit 3a that performs TDMA control, multiplexing circuits 3b and 3c that perform signal multiplexing processing, and a wired slave station 10
Number detection circuit 3 for detecting slave station numbers of -1 to 10-n
d, a distribution circuit 3e for distributing a signal to a route corresponding to the detected slave station number, a speed conversion circuit 3 for converting a signal speed from a transmission speed of a wireless transmission line to a transmission speed of a wired transmission line 14.
f, a speed conversion circuit 3g for converting the signal speed from the transmission speed of the wired transmission line 14 to the transmission speed of the wireless transmission line.

The radio transceiver 4 includes a transmission / reception unit 4a and a burst detection circuit 4b for detecting burst signals from the radio slave stations 5-1 to 5-n. The wired transceivers 13-1 to 13-n include a transceiver 13a and a wired slave station 1
It comprises a number detection circuit 13b for detecting the time slot number of the corresponding wired slave station from 0-1 to 10-n. The wireless slave stations 5-1 to 5-n are provided with a transmitting / receiving unit 5a.
And a control device 5b for performing TDMA control. The wired slave stations 10-1 to 10-n include a transmitting / receiving unit 10
a, a number detection circuit 10 for detecting a time slot number
b, a speed conversion circuit 10c, and a control device 10d for performing TDMA control.

The operation of the system configured as described above is as follows. First, a description will be given of signal transmission in the direction of a slave station in a wireless system. As shown in FIG. 3A, the signal S1 supplied from the control unit 3a to the wireless transceiver 4 in FIG. 2 is a signal of time slots # 1 to # 8 following the control signal time slot C. I have. However, the time slot is 8
Not only that, but further following, the description is omitted due to the size limitation of the paper. These signals are all transmitted simultaneously from the wireless transceiver 4 to the wireless slave stations 5-1 to 5-n. Each slave station receives a signal of a time slot assigned to itself from this signal.

If these time slots are represented by time slot # 1, as shown in FIG. 3B, word, STN, TS, and data signals are sequentially transmitted. The word is a signal for identifying the slave station that multi-directional multiplexing is performed, STN is a signal indicating a slave station number, TS is a time slot number, and data is a main signal. In this example, the wireless slave station 5-1 uses time slot # 3, and the wireless slave station 5-
The following description proceeds assuming that n uses time slot # 1. The downlink signal received by the wireless slave station 5-1 is S2, the uplink signal is S4, and the wireless slave station 5-n
The downlink signal received at S3 is S3, and the uplink signal is S5
It will be described as.

Uplink signals from the radio stations 5-1 to 5-n are received by the radio transceiver 4, and supplied to the multiplexing circuit 3b. Further, the burst detection circuit 4b detects a burst signal from a corresponding wireless slave station of the wireless slave stations 5-1 to 5-n, that is, a signal indicating a time slot number and a slave station number from the wireless slave station to be received. Then, it is supplied to the multiplexing circuit 3b. FIG. 3C shows the wireless slave station 5.
-1 and the control signal time slot C
Subsequently, the signal from the wireless slave station 5-1 is transmitted in the time slot # 3. FIG. 3D shows the wireless slave station 5-n.
The signal from the wireless slave station 5-n is generated in the time slot # 1 following the control signal time slot C. In the following description, the burst signal is represented by PRN, UNF, T
Each signal of S and data is transmitted in order. PRN is a principal signal which is a signal for extracting a clock, UN is a signal representing a uniflag and includes a slave station number, and TS is a signal representing a time slot number.

In this example, the signals of the time slots # 1 and # 3 in FIGS. 3C and 3D are supplied to the multiplexing circuit 3b as a signal S6 as shown in FIG. 3F. Therefore, the multiplexing circuit 3b supplies an output signal of the transmission / reception unit 4a to the control unit 3a based on the signal detected by the burst detection circuit 4b. Then, the control unit 3a converts the supplied signal into a TDM signal.
A control and supply to the exchange 1 of FIG.

FIG. 4 is a diagram showing a signal transmission state in the down direction of the wired slave stations 10-1 to 10-n. FIG. 4 (a) is the same as FIG. 3 (a) up to the distribution circuit 3e of FIG. Signal S shown in
1 is supplied to the distribution circuit 3e and the number detection circuit 3d.
Supplied to The number detection circuit 3d detects a time slot number and a slave station number included in each time slot, controls the distribution circuit 3e according to the detection result, and transmits a signal supplied to the distribution circuit 3e to the wired transceiver 13-. It sends to the one corresponding to the corresponding route among 1 to 13-n. Then, the signal sent from the distribution circuit 3e is speed-converted by the speed conversion circuit 3f so as to match the transmission speed of the wired transmission line 14.

The wireless transmission path needs to perform signal transmission in consideration of the traffic volume of the entire system during the busiest time.
In No. 4, the transmission speed may be lower than that of the wireless transmission path, since it is sufficient if the communication traffic at the busiest time of the corresponding wired slave station can be ensured.
In this example, the wired slave station 10-1 has time slots # 4 and #
7 and # 8, and the wired slave station 10-n uses two time slots # 5 and # 6, the transmission rate to be transmitted to the wired transmission path 14 is signal S.
1 is sufficient, that is, from the occurrence of time slot # 1 to the next occurrence of time slot # 1, the speed at which three time slots can be transmitted on the wired transmission path 14 is sufficient.

The speed conversion circuit 3f converts the speed of the supplied signal S1 and outputs a signal to the wire transceiver 1-1 for the wire slave station 10-1.
As shown in FIG. 4 (b), the time slot # 4, # 4 following the control signal time slot C
7. Transmit the # 8 signal. Also, as a signal S8 to the wired transceiver 13-n for the wired slave station 10-n, as shown in FIG.
6 is transmitted.

The signal S7 and the signal S8 are transmitted and received by the transmitting / receiving unit 13a.
Is transmitted to the wired transmission line 14 via the transmission line 10 and received by the transmission / reception units 10a of the wired slave stations 10-1 and 10-n, and returned to the original speed by the speed conversion circuit 10c.
In the speed conversion circuit 10c, the number detection circuit 10b detects the time slot number and the slave station number included in the time slot, and only the time slot including the slave station number is controlled by the control device at the timing of the original time slot. 10
d. As a result, the wired slave station 10-1 is configured as shown in FIG.
As shown as a signal S9 in (d), time slots # 4, # 7, and # 8 synchronized with the time slots of the wireless transmission path.
4 and the wired slave station 10-n
As shown as a signal S10 in (e), time slots # 5, # 5,
It is sent at the timing of 6.

As a result, the wired slave station 10-1 can perform communication only at the timing of the time slots # 4, # 7, and # 8.
The wired slave station 10-n can perform communication only in time slots # 5 and # 6. Communication can be performed with the same image as when these wired slave stations are housed in a conventional multidirectional multiplex system using a wireless transmission path.

FIG. 5 is a diagram showing signal transmission and reception when transmission is performed from the wired slave stations 10-1 to 10-n.
0-1 and 10-n are signals S1 in FIGS. 5 (a) and 5 (b).
1 and S12 are represented by time slots # 4 to # 8 shown in FIG.
To send. In this case, time slots # 4 to # 4
8 is synchronized with time slots # 4 to # 8 of the wireless transmission path. They are converted by the speed conversion circuit 10c as shown in FIG.
As shown in (d), the speed is converted so as to conform to the transmission speed of the wired transmission line 14, and transmitted as signals S13 and S14 from the transmitting / receiving unit 10a via the wired transmission line 14 and received by the transmitting / receiving unit 13a. . Since the signals shown in FIGS. 5C and 5D change the transmission speed, they are not synchronized with the time slots of the wireless transmission path.

As shown in FIGS. 5 (e) and 5 (f), the received signal is speed-converted as the signals S15 and S16 by the speed conversion circuit 3g into the same time slot as that of the wireless slave station. The time converted signal and the time slot and the slave station number are detected by the number detection circuit 13b and supplied to the multiplexing circuit 3c. It is transmitted as a signal S17 as shown. Then, in the multiplexing circuit 3b, the signal is multiplexed with the signal supplied from the wireless transceiver 4, and is supplied to the control unit 3a as a signal S18 as shown in FIG.
DMA control is performed.

In the above embodiment, the information of the slave station number and the time slot number is multiplexed in the time slot for transmitting the main signal of each slave station. However, this can be multiplexed in the control signal time slot and transmitted. is there. In addition, by performing the speed conversion in the wired slave station, the TDMA method in the wired slave station is matched with the wireless slave station, and the hardware and the firmware can be shared. The speed conversion in the wired slave station may be omitted. Further, in this embodiment, the transmission path of a path having a different transmission speed from the multidirectional transmission path is a wired transmission path, but may be a wireless transmission path having a different frequency from the multidirectional transmission path.

[0022]

As described above, the first aspect of the present invention is:
A part of the multi-directional route is a transmission line that is slower than that of the multi-directional route and is different from the multi-directional route. It is possible to transmit a signal without being interfered by another wireless system even in an installation location where the route cannot be used due to interference from another wireless system only on a specific route. . According to the second aspect of the present invention, the information of the slave station number and the time slot number is added to the time slot assigned to each slave station, and the route from the master station to the slave station is determined based on this information. At the time of the time slot used by the slave station that needs to change,
This has an effect that a corresponding slave station can be selected. According to the third aspect of the present invention, the information of the slave station number and the time slot number is added to the time slot used by each slave station, and the multiplex position of the time slot from the slave station to the master station is controlled by this information. The signal transmitted from the slave station can be multiplexed at the corresponding time slot position in the multi-way multiplex system, which has the effect of increasing the degree of freedom in line design.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a system configuration to which the present invention is applied.

FIG. 2 is a diagram showing a main part of FIG. 1 in detail.

FIG. 3 is a time chart showing transmission and reception of signals in a down direction with respect to a wireless slave station.

FIG. 4 is a time chart showing downlink signal transmission / reception to / from a wired slave station.

FIG. 5 is a time chart showing transmission and reception of signals in the upward direction from a wired slave station.

FIG. 6 is a block diagram illustrating an example of a conventional system.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 exchange, 3 control device, 4 wireless transceiver, 5-1
To 5-n, 10-1 to 10-n: slave station, 9, 13-
1 to 13-n: Wired transceiver, 3d, 10b, 13b
... Number detecting device, 3e ... distribution circuit, 3f, 3g, 10c
... speed conversion circuit, 14 ... wired transmission path.

Claims (3)

(57) [Claims] 1. A demand assignment system comprising a master station as an upper station and a plurality of slave stations as lower stations, and allocating a time slot between the slave station and the master station only when a call occurs in the slave station. In a multi-directional multiplex communication system that performs communication, a transmission rate of a predetermined route among multi-directional routes from a master station to a slave station is converted so that the transmission speed is lower than that of the multi-direction route .
A speed conversion means that, Bei a controller to transmit at different transmission paths and a signal converted the route the multi-directional route by the speed converting means
Multidirectional multiplex communication system characterized by obtaining 2. The method of claim 1, the control device is thus possible to determine a route to the master station to the information of the slave station number assigned to the time slots allocated to each slave station and a time slot number A multidirectional multiplex communication system characterized by the above-mentioned. 3. The method of claim 1, the control device multiplexing position of the time slots of the information of the slave station number assigned to the time slot in which each slave station uses the time slot number therefore from the slave station to the master station A multi-directional multiplex communication system, comprising: