JPH04239240A - Point/multipoint transmission system - Google Patents

Abstract

PURPOSE:To enable selective starting for each calling against respective slave devices regardless of the states of the other slave devices by deciding a signal area allocated for each slave device and making the calling recognize to the slave device while including a signal notifying the calling against the slave device with the calling in the signal area. CONSTITUTION:A signal is sent from a main device 100 to respective slave devices 103 to 10K, this decening signal is composed of channels #1 to #K successively allocated to a frame synchronization signal and the slave devices 103 to 10K. A calling signal AS is sent only by the channel allocated to the slave device to be called.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a point/multipoint optical transmission system, and more specifically, the present invention relates to a point/multipoint optical transmission system, and more specifically, the present invention relates to a point/multipoint optical transmission system. This invention relates to a point/multipoint optical transmission system that allows slave devices to be activated independently for each call.

0002

[Background Art] In recent years, with the development of transmission technology, point/multipoint transmission systems (hereinafter referred to as multipoint transmission systems) in which one main device and a plurality of slave devices simultaneously transmit data via one transmission path have been introduced. ) has been developed. FIG. 1 shows a schematic configuration of a multipoint transmission system using light as a medium. In the figure, reference numeral 100 is a main device, 101 is an optical fiber, 102 is an optical branch circuit, and 103 is a main device.
, 104, 10K are slave devices. These slaves 10
In order to reduce power consumption, the 3,104, and 10K systems use a so-called call-by-call activation method, in which the power is turned off or turned off when there is no communication, and the power is turned on each time there is communication. When the slave devices 103, 104, and 10K receive an incoming call signal AS from the main device 100 indicating an incoming call, they turn on the power, start up, and start communication. Conventionally, the presence or absence of a downlink signal from the main device 100 has been used as such an incoming call signal AS. When there is an incoming call, the main device 100 sends a signal, and when there is no incoming call, there is no signal. In this case, the slave devices 103, 104, and 10K detect the presence or absence of the incoming call signal AS based on the power of the received signal or from the timing component of the received signal.

0003

[Problems to be Solved by the Invention] By the way, in the above conventional multipoint transmission system, the slave device 103
, 104, 10K, the main device 100 sends an incoming call signal AS, so all the slave devices 103, 104, 10K are activated.
It was difficult to receive calls selectively. Additionally, a separate signal bit was required to notify an incoming call when any slave device was communicating. This invention was made in view of the above circumstances, and allows each slave device to be activated independently for each call, regardless of the status of other slave devices (during communication, in the middle of startup, inactive, removed, etc.). Point/multipoint optical transmission system (hereinafter referred to as multipoint transmission system)
is intended to provide.

0004

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim 1 provides a point/multipoint transmission system in which one main device and a plurality of slave devices communicate at the same time. A signal area assigned to each slave device is determined in the frame of the downlink signal sent to the slave device, and a signal notifying the slave device of the incoming call is included in the corresponding signal region. to cause the slave device to recognize the incoming call, and when the slave device recognizes the incoming call,
The slave device is characterized in that it starts up and performs reception.

[0005] The invention as set forth in claim 2 is characterized in that the signal notifying the incoming call consists of repeating short signal patterns.

[0006] In the invention according to claim 3, each of the short signal patterns is a binary one of n bits (n is a positive integer).
It is characterized by consisting of alternating repetitions of and binary 0.

[0007] The invention as set forth in claim 4 is characterized in that the pattern of the signal notifying the incoming call is set differently for each of the slave devices.

[0008] The invention as set forth in claim 5 is characterized in that each of the slave devices is capable of detecting whether or not the signal notifying the incoming call is sent to itself.

[0009] In the invention as set forth in claim 6, it is determined by a correlator whether or not the signal notifying the incoming call has a correlation with a specific pattern uniquely determined for each slave device, and when the correlation is found, , the slave device is characterized in that it recognizes incoming calls to itself.

[0010] The invention according to claim 7 provides the binary 1 and 2
The slave device is provided with a band-pass filter having a frequency equal to the repetition period of the base 0, and the signal indicating the incoming call is detected from the output of the band-pass filter.

[0011] According to an eighth aspect of the invention, when the signal informing the incoming call is detected, regardless of whether the call is to oneself or not, the power is first turned on and the receiver is operated; If a signal pattern notifying an incoming call is found in the signal area allocated for its own slave device, it will determine that the call is incoming to itself, and if it is not found in the same signal area, it will turn off the power and stop receiving. It is characterized by the fact that

0012

[Operation] According to the configuration of the present invention, the state of other slave devices (
It becomes possible to selectively activate each slave device on a call-by-call basis regardless of whether the slave device is communicating, in the middle of activation, inactive, disconnected, etc. Therefore, power saving can be achieved.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) The schematic configuration of the multipoint transmission system according to the first embodiment of the present invention is the same as that shown in FIG.
The explanation will be omitted. FIG. 2(a) shows the frame structure of the downlink signal used in this example, that is, the signal sent from the main device 100 to each slave device 103, 104, 10K. and channels #1, #2, #.K sequentially assigned to K slave devices 103, 104, 10K. Then, select the channel (
The incoming call signal AS is sent only by the area (area). FIG. 2(b) is a frame configuration diagram of a downlink signal when there is an incoming call to the slave device 103, in which a specific pattern P as a predetermined incoming call signal AS is displayed on channel #2.
The data is sent to the slave device 102 by the following. According to this configuration, the states of the other slave devices 103 and 10K (
It is possible to selectively send an incoming call signal only to a slave device that receives an incoming call, regardless of whether the device is communicating, in the middle of startup, inactive, disconnected, etc. Furthermore, since the channel is not used when a call arrives, there is no need to newly provide another signal bit.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The difference between this second embodiment and the first embodiment is that, instead of the specific pattern P (FIG. 2(b)), a shorter pattern P1 is used as the incoming call signal AS.
The point is that a specific pattern consisting of repetitions of is used (see FIG. 2(c)). According to the configuration of this example, it is possible to repeatedly obtain the incoming call detection output of the slave device, which prevents incorrect incoming call detection due to distortion or noise in the transmission path, making incoming call detection more reliable. Become.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In this third embodiment, as the pattern P1 (FIG. 2(c)), the binary signal 111.
...000... or 000...111... patterns are used. The patterns in this example therefore become rectangular waves as shown in FIG. 2(d), and the signal has a sine wave component whose period is the length of these patterns. Therefore, according to the configuration of this example, incoming call detection in the slave device only needs to detect the sine wave component, which makes the detection even easier. Note that the same effect can be obtained even when the shortest pattern 10 or 01 is used.

Here, the slave devices 102, 103, 10K have a transmitting circuit 200 and a receiving circuit 201, as shown in FIG.
, an incoming call signal detector 202 , and a power source 203 . In the slave devices 102, 103, and 10K having such a configuration, the signal from the optical fiber (transmission line) 103 is first inputted by the incoming call signal detector 202 before being inputted by the receiving circuit 201, and the incoming call is detected. When detected, the power supply 203 is turned on, and thus the operation of the receiving circuit 201 starts. In this way, each call is activated. In this way, the incoming call signal detector 202 needs to be operated all the time, and power-down is applied to other systems. Therefore, it is important for the incoming call signal detector 202 to be as simple and low-power as possible for activation on a call-by-call basis.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. FIG. 4 is a block diagram showing the configuration of the incoming call signal detector 202 in this example. As shown in the figure, this incoming call signal detector 202 includes a specific pattern generator 300 that generates a specific pattern P or P1, and a correlator 3.
01. In this configuration, the correlator 301 calculates the correlation value between the specific pattern P or P1 supplied from the specific pattern generator 300 and the input signal supplied from the main device 100, and converts the calculation result into an incoming call detection value. Output as . If there is an incoming call, pattern P or P1 is input, so an incoming call detection value of 1 (correlation) is obtained, and an incoming call is detected. According to the above configuration, the correlator 3
Since 01 operates continuously on the input signal, there is no need to extract accurate timing or synchronization from the input signal, and incoming calls can be detected using only the correlator 301 without operating the receiving circuit 201.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. As shown in FIG. 5, the incoming call signal detector 202 in this example includes a bandpass filter 401 that passes only a frequency f0, which will be described later. The same specific pattern as in the third embodiment is used for the incoming call signal AS. That is, the binary signal 111...000...
, or 000...111... are used as a specific pattern of the incoming call signal. As described above, this specific pattern has a sine wave component equal to the repetition period, so its frequency f0 is detected by the band pass filter 401. According to the above configuration, the circuit configuration of the incoming call signal detector 202 is simplified. For example, if the circuit is configured with passive components, power consumption can be reduced.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described. FIG. 6 shows slave devices 103, 104,
FIG. 2 is a configuration diagram of a call-by-call activation device provided in 10K. This per-call activation device is a device that controls the power supply at the time of activation for each call, and includes an incoming call signal detector 202, a flip-flop 500 for power supply, a power supply 203, an equalizer 501, a synchronization extraction circuit 502, and a decoder. 503, a switching element 504, a mismatch determination circuit 505, and a specific pattern generator 300. In the above configuration, the incoming call signal detector 202
receives a specific pattern of the incoming call signal (see Examples 1, 2, and 3) sent from the main device, and sends a detection signal to the flip-flop 500. flip flop 5
00 enters the set state upon receiving the detection signal and turns on the power source 203. When the power source 203 is powered on, receiving circuits such as the equalizer 501, the synchronization extraction circuit 502, and the decoder 503 operate, making it possible to identify the channel (signal position) assigned to itself. Then, the switching element 504 is turned on only when the channel assigned to itself arrives.

[0020] The incoming call signal AS that has passed through the switching element 504 in the on state is judged by a non-coincidence determiner 505 as to whether or not it matches the specific pattern output from the specific pattern generator 300. If they do not match, the mismatch determiner 505 sends out a signal. When flip-flop 500 receives a signal from mismatch determiner 505, it enters a reset state and returns power supply 203 to power down. On the other hand, if the incoming call signal AS that has passed through the switching element 504 matches the specific pattern output from the specific pattern generator 300, the mismatch determiner 505 does not send the signal to the flip-flop 500.
3 keeps the power on. In this way, according to the above configuration, if there is no incoming call to itself, the power is turned on once, but the power is immediately powered down, so power consumption is low and selective activation of incoming calls can be realized.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described. The main difference between the call-by-call activation device of this example and that of the sixth embodiment (FIG. 6) is that the incoming call signal detector 202 (FIG. ), an incoming call signal detector 506 that can detect that it is a specific pattern assigned to itself is used, and a mismatch determiner 505,
This is the point where the specific pattern generator 300 is removed (FIG. 7).
. In this example, a different specific pattern is assigned as the incoming call signal AS to each slave device 103, 104, 10K. When employing specific pattern groups corresponding to the first and second embodiments, different patterns can be easily selected. On the other hand, when adopting the specific pattern group corresponding to the third embodiment, it is preferable to select patterns with different periods.

In the configuration of FIG. 7, the received input enters the incoming call signal detector 506, but the incoming call signal detector 506 detects only the specific pattern assigned to itself. Therefore, in the case of an incoming call to itself, a detection signal is sent to flip-flop 500. The flip-flop 500 is
When the detection signal is supplied, it enters a set state and turns on the power source 203. In this way, the slave device starts up. On the other hand, in the case of an incoming call to another slave device, the specific pattern is different, so the incoming call signal detector 506 cannot detect the incoming call signal and remains powered down. Therefore, according to this configuration, selective activation of each slave device is possible.

[0023] In the above embodiment, the case where the transmission line is an optical fiber 103 has been described, but the present invention is not limited to an optical fiber, but can also be applied when the transmission line is an electric cable. It is.

[0024]

Effects of the Invention As explained above, according to the present invention, a selective call can be made to each slave device regardless of the status of other slave devices (during communication, in the middle of startup, during suspension, during removal, etc.). It can be started every time. Therefore, power saving can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a multipoint transmission system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a frame of a downlink signal used in the embodiment of the present invention, that is, a signal sent from a main device to each slave device.

FIG. 3 is a block diagram showing the configuration of a slave device used in a third embodiment of the invention.

FIG. 4 is a block diagram showing the configuration of an incoming call signal detector used in a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing the configuration of an incoming call signal detector used in a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of a call-by-call activation device used in a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing the configuration of a call-by-call activation device used in a seventh embodiment of the present invention.

[Explanation of symbols]

100 Main device 103, 104, 10K Slave device #1, #2, #
3 Channel (signal area) 201 Receiving circuit 202, 506 Incoming call signal detector 203
Power supply 300 Specific pattern generator 301 Correlator 401 Bandpass filter 500 Flip-flop

Claims (8)

[Claims] Claim 1: In a point/multipoint transmission system in which one main device and a plurality of slave devices communicate at the same time, in a frame of a downlink signal sent from the main device to the slave devices, a signal is assigned to each slave device. A signal area is determined, and a signal informing the slave device of the incoming call is included in the corresponding signal area to cause the slave device to recognize the incoming call, and the slave device recognizes the incoming call. A point/multipoint transmission method characterized in that when the slave device activates and receives data. 2. The point/multipoint transmission system according to claim 1, wherein the signal notifying the incoming call consists of repeating short signal patterns. 3. Each of the short signal patterns has n
3. The point/multipoint transmission system according to claim 2, wherein the bit (n is a positive integer) consists of alternating repetition of binary 1 and binary 0. 4. The point/multipoint transmission system according to claim 1, wherein the pattern of the signal notifying the incoming call is set to be different for each slave device. 5. The points according to claim 1, characterized in that each slave device is capable of detecting whether or not the signal notifying the incoming call is sent to itself. Multipoint transmission method. 6. A correlator determines whether or not the signal notifying the incoming call has a correlation with a specific pattern uniquely determined for each slave device, and when a correlation is found, the slave device 6. The point/multipoint transmission system according to claim 4, wherein the point/multipoint transmission system recognizes an incoming call. 7. A band-pass filter having a frequency equal to the repetition period of the binary 1 and binary 0 is provided in the slave device, and a signal indicating the incoming call is detected from the output of the band-pass filter. The points of claim 3 or 5 that
Multipoint transmission method. 8. When the signal notifying the incoming call is detected, regardless of whether the call is to oneself or not, the power is turned on, the receiver is operated, and the signal notifying the incoming call is detected. Claim characterized in that if a pattern is found in the signal area allocated for the own slave device, it is determined that there is an incoming call to itself, and if it is not found in the same signal area, the power is turned off and reception is discontinued. Point/multipoint transmission method described in 1.