JPH05300166A - Burst signal multiplex control system - Google Patents

Abstract

PURPOSE:To reduce waiting time by using an idle time slot, which is not used for communication, and transmitting a call originating request signal after the lapse of peculiar delay time allocated to each slave station. CONSTITUTION:The call originating request signal transmitted from a slave station NT #i to the idle time slot is sent to a call originating request signal processing circuit 104 by an SW 103 at a master station SLT and after it is identified here which NT transmits this signal, a TS is allocated to a TS managing control circuit 105. Then, a use signal is written and transmitted to the NT#i by a TS use/non-use signal inserting circuit 106. After this signal is received, at the NT#i, an SW 203 is switched so as to transmit signals from an up communication signal processing circuit 208. In this case, since a call originating signal transmitted from each NT is delayed within one time slot, even when the signal is received at the SLT, those signals are not collided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burst signal multiplexing control system which uses a passive double star type transmission line and sets a communication line between a master station and a slave station based on a call from a slave station.

[0002]

2. Description of the Related Art A system configuration of a passive double star (PDS) type transmission line is shown in FIG. Conventionally, when performing TDMA using a PDS type transmission line, the following two types of methods have been used.

As shown in FIG. 5, the first method is to provide a time slot dedicated to a call request in a signal time slot transmitted from a slave station (NT) to a master station (SLT) and use this time slot. Each slave station transmits a call request signal. In this method, as shown in FIG. 6, there is a possibility of collision when call signals from a plurality of NTs arrive at the SLT at the same time, so it is necessary to perform control for collision detection and avoidance.

The second method is, as shown in FIG. 7, a polling method in which a dedicated time slot for calling each NT is provided in the signal time slot transmitted from NT to SLT. When there is a call request at each NT, a reply is returned and a call is made when polled by the SLT. In this case, although the calling signals do not collide with each other as described above, each NT must wait a maximum of nT time even if a calling request is made.

[0005]

In the first method described above, the calling signals from a plurality of slave stations NT are simultaneously transmitted to the master station SLT.
When the vehicle arrives at, there is a possibility of collision, and there is a problem that it is necessary to perform control for collision detection and avoidance.

The second method has a problem that each slave station NT has to wait a maximum of nT time when a call request is made.

Further, both of the above methods have a problem that they are not efficient in terms of bandwidth utilization because they require a time slot dedicated to calling.

The present invention has been made in view of the above,
The purpose of this is to provide burst signal multiplexing that does not require a dedicated calling time slot, does not collide with the calling signal at the master station, and has a small waiting time for calling the slave station. To provide an integrated control method.

[0009]

[Means for Solving the Problems]
Therefore, the burst signal multiplexing control system of the present invention is
1: n passive double star type consisting of a station and n slave stations
Time division in units of time slot length T using a transmission network
According to the request of the slave station,
When setting a transmission line between the main station and
Indicates whether the time slot is used for communication
Area is set up, and the slave station is in the downlink signal from the master station to the slave station.
Detects an empty time slot in the
Transmission line setting is required during the empty time slot in the signal.
Burst where the required signal length is t and nt <T
Assign a signal to each slave station from the beginning of the time slot
Transmission after the inherent delay time di (1 ≦ i ≦ n)
The main point is that.

[0010]

In the burst signal multiplexing control system of the present invention, when the slave station attempts to make a call, it detects an empty time slot in the downlink signal from the master station to the slave station and detects the time slot in the uplink signal from the slave station to the master station. A burst signal is transmitted during the idle time slot after a specific delay time assigned to each slave station.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a burst signal multiplexing control system according to an embodiment of the present invention.
In the figure, the TS management control circuit 105 of the master station SLT
Writes a signal indicating, for each time slot, whether or not the time slot is used for communication in the downlink signal through the TS use / non-use signal insertion circuit 106, and through the downlink signal transmission circuit 102, each slave station. Transmit to NT. NT # i sends this signal to the downlink signal receiving circuit 201
To receive by.

The received signal is detected by the TS use / non-use signal detection circuit 204, and the calling request control circuit 20 is detected.
Sent to 6. Detects an empty time slot and NT
When #i wants to make a call, the call request control circuit 206
Generates a signal for calling by the calling request signal generation circuit 206 and sends it to the SW 203 through the delay generation circuit 207. At the same time, the call request control circuit 205 switches the route of the SW 203, sends the signal from the delay generation circuit 207 to the upstream signal transmission circuit 202, and transmits it to the SLT. In SLT, the TS management control circuit 105 sends the SW 103 to the call request signal processing circuit 104 when it is an empty time slot, and to the upstream communication signal processing circuit 108 when it is being used for communication. Control to switch routes.

The call request signal transmitted from NT # i in the empty time slot is sent to the call request signal processing circuit 104 by the SW 103 in the SLT, and after identifying from which NT the signal is sent, TS is transmitted. TS is allocated by the management control circuit 105, and the TS use / non-use signal insertion circuit 10
A use signal is written by 6 and transmitted to NT # i.
In NT # i, after receiving this, the SW 203 is switched to transmit the signal from the upstream communication signal processing circuit 208.

In this case, the relationship between the delay amount di given to each NT, the time slot length T, and the call request signal length t is shown in FIG. di is fixed in advance when NT is installed in the system. FIG. 2 shows a case where four NTs are present, and by giving a delay di to a calling signal transmitted from each NT within one time slot, these signals collide when received by SLT. This makes it unnecessary to perform collision detection and the accompanying management control.

When the number of slave stations is n, the signal length t of the calling request signal must satisfy nt <T (1) in order to avoid collision in the SLT.

As an embodiment of the present invention satisfying the equation (1), an example using a cell-based ATM transmission frame is shown in FIG. In the cell-based ATM transmission system, one PLOAM cell (physical layer OAM cell) and m-1 ATM cells, a total of n cells, are set as one time slot and assigned to communication. In the downlink PLOAM cell, a TS identifier indicating the serial number of the TS, a TS use signal indicating whether or not the TS is used for communication, an NT identifier indicating which NT the TS is assigned, NT
Defines a delay amount setting signal that represents the delay amount di to be set.

In the upstream PLOAM cell, a TS identifier, an NT identifier, and a call request signal area are defined. Up P
The LOAM cell has a guard time, preamble, and delimiter area as a signal area unique to the burst signal. When the NT requests to make a call, the call request signal of the PLOAM cell and the necessary signal are written to the NT identifier and P
Only send LOAM cells.

In the SLT, after the call request signal processing circuit 104 in FIG. 1 processes this signal, TS is assigned and the TS use signal of the PLOAM cell of the assigned time slot is set to "in use". , And the assigned N
By writing the NT identifier of T, the time slot is assigned to NT. NT is the TS identifier in the downlink signal and NT
By detecting the identifier, the time slot assigned to itself is identified and communication is started. At this time, the time slot for which a call request is made and the time slot assigned for communication do not necessarily have to match, and a plurality of time slots may be assigned in some cases.

Since the PLOAM cell has only 1 / m of the time slot length T, theoretically m NTs can be accommodated in one system. The value of m depends on the system requirements, but is usually 20-
Since it is set to 30 (Nagasaku et al., "A Study on Cell-based Passive Double-star Transmission System", IEICE 1991 Spring National Convention, B-686.), The cell-based ATM transmission system will be accommodated. NT number 8-16
(D.Mestdagh et.al., "ATM Local access over passive
optical networks ", 3rd IEEE Workshop on Local Optic
al Network, G3.1.A.Ishikura et.al., "A cell-based mu
ltipoint ATM transmission system fora passive doub
le star access network ", 3rd IEEE Workshop on Local
OpticalNetwork, G3.4.) Can sufficiently satisfy the condition of the expression (1), and the present invention can be easily implemented by using the PLOAM cell.

[0021]

As described above, according to the present invention,
Since the call request signal is transmitted after the unique delay time assigned to each slave station, as well as using an empty time slot that is not used for communication, it is not necessary to provide a time slot dedicated to the call and the master station Therefore, the call request signals do not collide with each other, and the waiting time for calling the slave station can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a burst signal multiplexing control system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of transmitting a call request signal in the burst signal multiplexing control system shown in FIG.

FIG. 3 is a diagram showing a configuration example of a PLOAM cell frame when the burst signal multiplexing control system of the present invention is applied to a cell-based ATM transmission system.

FIG. 4 is a system configuration diagram of a passive double star type transmission line.

FIG. 5 is an explanatory diagram showing a configuration example of a time slot used in a conventional method.

FIG. 6 is an explanatory diagram showing an example of a call request signal collision in the conventional method.

FIG. 7 is an explanatory diagram showing a configuration example of a time slot used in a conventional method.

[Explanation of symbols]

 1 Star Coupler 101 Upstream Signal Reception Circuit 102 Downstream Signal Transmission Circuit 103 SW 104 Calling Request Signal Processing Circuit 105 TS Management Control Circuit 106 TS Use / Unuse Signal Insertion Circuit 107 Downstream Communication Signal Processing Circuit 108 Upstream Communication Signal Processing Circuit 201 Downstream Signal reception circuit 202 Upstream signal transmission circuit 203 SW 204 TS use / non-use signal detection circuit 205 Call request control circuit 206 Call request signal generation circuit 207 Delay generation circuit 208 Up communication signal processing circuit 209 Down communication signal processing circuit NT Slave station SLT main station

Claims (1)

[Claims] 1. A request of a slave station in burst multiplex transmission by time division in units of a time slot length T using a 1: n passive double star type transmission network consisting of one master station and n slave stations. When a transmission line is set up with the master station for each call according to the above, the time slot is provided with an area for displaying whether or not it is used for communication, and the slave station is a downlink signal from the master station to the slave station. A signal length for detecting an empty time slot and requesting transmission line setting during the empty time slot in the upstream signal from the slave station to the master station is t, and n
A burst signal satisfying t <T is assigned a delay time di assigned to each slave station from the beginning of the time slot.
A burst signal multiplexing control method, wherein transmission is performed after (1 ≦ i ≦ n).