JP3296255B2 - Frame phase intermittent adjustment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a main device comprising:
The present invention relates to a method for adjusting a frame phase intermittently in a time division multiplex transmission system in which one or a plurality of slave devices are connected by a transmission line.

[0002]

2. Description of the Related Art A conventional frame phase adjustment method used in a bidirectional time division multiplex transmission system using a phase adjustment channel is disclosed in Japanese Patent Application Laid-Open No. 63-84221. An example in which this conventional adjustment method is applied to an optical subscriber communication device using an optical fiber is disclosed in Japanese Patent Application Laid-Open No. 7-250152, and will be described with reference to FIGS.

FIG. 6 is a block diagram of an optical communication apparatus disclosed in Japanese Patent Application Laid-Open No. 7-250152.

[0004] In this prior art device, in order to reduce the amount of optical fiber and the number of electric / optical conversion circuits in the station side communication device 20, one station side communication device 20 which is a main device,
N subscriber communication devices 31 to 3N serving as slave devices are
They are connected in a point / multipoint format. That is, the optical fiber 100 is connected to the station-side communication device 20, the optical fibers 101 to 10N are connected to the subscriber-side communication devices 31 to 3N, and transmission is performed between the optical fiber 100 and the optical fibers 101 to 10N. They are connected by a star coupler 110 that splits or combines signals.

FIG. 7 is a schematic diagram showing an example of the configuration of a channel used for transmission / reception between the station side communication device 20 and the subscriber side communication devices 31 to 3N during a frame period T.

In the first half TS of the frame period T, a downlink control channel Dd for transmitting a control frame from the station side communication device 20 to the subscriber side communication devices 31 to 3N, and each subscriber side And downlink information channels Bd1 to BdN for transmitting information frames to the communication device. In the second half TR of the frame period T, an uplink control channel Du that sends out a control frame from one of the subscriber communication devices 31 to 3N to the station communication device 20, and each of the subscriber communication devices 31 to 3N Uplink information channels Bu1 to BuN for transmitting information frames to the station side communication device 20
And In FIG. 7, the subscriber-side communication device 3i
Shows an example using the uplink control channel Du.

[0007] The station side communication device 20 has an uplink control channel D
u as a phase adjustment channel, and the subscriber communication device 3
The transmission delay amount for i is obtained by measurement. On the basis of the transmission delay amount obtained by this measurement, the uplink information channel B
The transmission position of the information frame in ui is calculated, and the calculated transmission position is indicated to the subscriber side communication device 3i in the downlink control channel Dd of the subsequent frame period.

[0008] Each of the subscriber communication devices 31 to 3N transmits the uplink information channels Bu1 to BuN at the transmission position indicated by the downlink control channel Dd, thereby transmitting the phase of the information channel received by the station communication device 20. To adjust.

FIG. 8 shows the measurement of transmission delay transmitted and received between the station side communication device 20 and the subscriber side communication device 3i when the subscriber side communication device 3i uses the uplink control channel Du as a phase adjustment channel. It is a figure showing an example of frame Dui.

It is assumed that one of the subscriber communication devices is connected to the station communication device 20 via the shortest possible transmission path, and this subscriber communication device is assumed to be 3Z. Further, it is assumed that another subscriber-side communication device is connected to the station-side communication device 20 via the longest possible transmission path, and this subscriber-side communication device is assumed to be 3X. The round trip transmission delay between the station side communication device 20 and the subscriber side communication device 3Z is RZ, and the station side communication device 20 and the subscriber side communication device 3X
Let RX be the round trip transmission delay between the two.

At this time, in the station side communication device 20,
After the transmission of the last downstream frame BdN, the frame cannot be received during the transmission delay RX because of the afterglow GX due to reflection from the farthest subscriber communication device 3X. In the station communication device 20, the transmission delay measurement frame D from the nearest subscriber communication device 3Z is determined.
In order to normally receive uZ, transmission of the transmission delay measurement frame is performed after a predetermined delay amount W has elapsed after the subscriber side communication device has received the end of the downstream frame BdN. Here, the delay amount W is equal to or larger than (RX-RZ).

The subscriber-side communication device 3i and the office-side communication device 2
0, the round trip transmission delay Ri between the station side communication device 20
In the above, after the transmission of the last downlink frame BdN is completed, the delay amount until the transmission delay measurement frame Dui is received is measured, and the delay amount W is obtained by subtracting the delay amount W from the obtained value.

The minimum bandwidth required by the phase adjustment channel Du in the frame period T is the transmission delay measurement frame DuZ transmitted by the subscriber communication device 3Z closest to the station communication device 20, and the farthest subscription. The transmission delay measurement frame DuX transmitted by the communication device 3X of the sender and the delay measurement frame Dx
This value is the sum of the bandwidth occupied by uX.

The above-mentioned conventional example is an example in which a two-way signal is multiplexed on one transmission line in a time-division manner. However, even when an upstream transmission line and a downstream transmission line are independently provided, the same method is used. The phase adjustment is performed.

[0015]

Generally, in the field of communication, it is necessary to increase transmission capacity and transmission distance in order to reduce the amount of required lines. In a system that performs bidirectional time-division multiplexing transmission using the phase amount adjustment method found in the above-described conventional example, if the transmission distance that can be accommodated is increased, the bandwidth occupied by the phase adjustment channel increases, which increases There is a problem that the transmission band is reduced by the amount.

The present invention has been made in view of such a problem, and measures transmission delay intermittently and provides a transmission band in a phase adjustment channel to provide high-speed communication or long-distance communication. It is an object of the present invention to provide a method for adjusting a frame phase intermittently in a communication system for performing communication.

[0017]

SUMMARY OF THE INVENTION To solve this problem, the present invention focuses on the fact that the amount of transmission delay does not change at high speed. , A transmission band is provided in the phase amount adjustment channel.

As a result, since information can be transmitted to the phase adjustment channel, a large transmission capacity can be obtained as compared with the conventional device, and high-speed communication or long-distance communication can be performed.

Also, the present invention focuses on the fact that a large bandwidth is rarely required in both directions at the same time in communications between computers, and the position of the phase adjustment channel separating the upstream band and the downstream band is determined. Variable configuration.

As a result, the capacity of the upstream band and the capacity of the downstream band can be changed as required, so that high-speed communication or long-distance communication using the transmission capacity more effectively can be performed as compared with the conventional apparatus.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION
In a communication system provided with a phase adjustment channel for measuring a transmission delay amount between a slave device and a master device performing bidirectional time-division multiplex transmission between the master device and the slave device, the communication between the slave device and the master device
The measurement of the transmission delay amount is performed in the intermittent frame, measuring transmission delay
The frame period without receiving a constant frame is intended to allocate a transmission bandwidth for transmitting and receiving Oite information frame to the phase adjustment channel in a communication system may vary the distance of the transmission path has the effect of transmission capacity increases.

According to a second aspect of the present invention, the transmission delay from the slave unit to the main unit is measured for an upstream frame for performing bidirectional time division multiplex transmission between the master unit and a plurality of slave units. In a communication system having a phase adjustment channel,
Measurement of transmission delay with intermittent frames, and transmission delay measurement
In the frame period without receiving a frame it is intended to allocate a transmission bandwidth for transmitting and receiving Oite information frame to the phase adjustment channel, in a communication system that branching and coupling a transmission path of various distances has the effect of transmission capacity increases.

The third aspect of the present invention is the first aspect of the present invention.
Or the frame phase intermittent adjustment method according to claim 2, wherein the transmission path, each uplink transmission path for transmitting the frame from the slave device to the main unit, and the downlink transmission path for transmitting the frame to the slave device from the main device The communication system is characterized by being constituted by independent transmission paths, and has a function of increasing transmission capacity in a communication system having independent transmission paths in the upstream and downstream directions.

[0024] The invention according to claim 4 of the present invention is the invention according to claim 1.
Alternatively, in the frame phase intermittent adjustment method according to claim 2, the start position of the phase adjustment channel is a relative position from the end of the downstream frame, so that the transmission capacity of the downstream frame is dynamically changed as necessary. The information transmitted in the uplink direction and the information transmitted in the downlink direction are rarely simultaneously generated. In a communication system rarely occurring at the same time, the uplink transmission capacity and the downlink transmission capacity are changed as necessary. This has the effect of efficiently operating the transmission capacity.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be specifically described with reference to FIGS.

The first embodiment is applied to an optical communication device for connecting two terminals using an optical fiber and an optical communication system, but is intended for connection to a telephone, a computer network or the like. The present invention can also be implemented in a communication device and a communication system using the above, or a communication device and a communication system using a transmission path other than light, such as electric wires and radio waves. Further, in the present embodiment, a communication system including one main device and one slave device has been described as an example, but the communication system in which a plurality of slave devices shown in the conventional example are connected is similarly implemented. And the same effect can be obtained.

FIG. 1 is a block diagram of an optical communication device and an optical communication system for connecting a LAN at a subscriber's house and a LAN in a station using an access network according to an embodiment of the present invention. The optical communication device and the optical communication system use the optical line terminal 20 as a main device in order to improve the reliability of the transmission path.
And a subscriber communication device 30 serving as a slave device are connected in parallel by using optical fibers 100 to 10N passing through a plurality of paths. The station-side communication device 20 and the optical fibers 100 to 10N are connected by a star coupler 110 that branches or couples a transmission signal. The subscriber communication device 30 and the optical fibers 100 to 10N are connected by a switch 120 that can select and switch one optical fiber to be used.

Terminals are connected to the station side communication device 20 and the terminal side communication device 30, respectively. TDMA (time division multiplex access) circuits 200 and 300 perform bidirectional time division multiplex transmission via optical fibers. Do.

The switch 120 secures the reliability of the transmission line by switching to another optical fiber and connecting it when there is a failure in the selected optical fiber 10i.

Next, in the communication system configured as described above, the station-side communication device 20 and the subscriber-side communication device 30
FIG. 2 shows the configuration of a channel used for transmission and reception between
This will be described with reference to FIG. As shown in FIG. 2, the first half TS of the frame period T includes a downlink control channel Dd for sending a control frame from the station side communication device 20 to the subscriber side communication device 30, and a subscriber side communication channel from the station side communication device 20. Device 30
Information channel Bd that sends out information frames to
It is composed of The second half TR of the frame period T includes an uplink control channel Du for sending a control frame from the subscriber side communication device 30 to the station side communication device 20 and an information frame from the subscriber side communication device 30 to the station side communication device 20. And an uplink information channel Bu to be transmitted.

The station-side communication device 20 has an uplink control channel D
u as a phase adjustment channel, and the subscriber communication device 3
The transmission delay amount with respect to 0 is obtained by measurement. Based on the transmission delay amount obtained by this measurement, the uplink information channel Bu
Is calculated, and the transmission position calculated on the downlink control channel Dd in the subsequent frame period is instructed to the subscriber-side communication device 30. The subscriber-side communication device 30 retains the transmission position indicated on the downlink control channel Dd, and thereafter retains the transmission information at the retained transmission position until a new transmission position is indicated.
Is transmitted. Through a series of these operations, the phase of the information channel received by the station communication device 20 is adjusted.

Next, in the channel configuration thus configured, the station-side communication device 20 and the subscriber-side communication device 30
The configuration of the delay measurement performed between the two will be described with reference to FIG. As shown in FIG. 3, in the subscriber communication device 30 connected via the optical fiber 10i, after receiving the end of the information frame Bd from the station communication device 20, the time of the delay amount W is increased. And transmits a transmission delay measurement frame.

Assuming that the optical fiber is the shortest possible transmission path of the optical fibers 101 to 10N, this optical fiber is assumed to be 10Z. Further, it is assumed that the optical fiber is the longest possible transmission path of the optical fibers 101 to 10N, and the optical fiber is 10X. The delay amount W is equal to the optical fiber 1
0X, the round trip transmission delay amount RX between the station-side communication device 20 and the station-side communication device 30, and the station-side communication device 20 and the station-side communication device connected via the optical fiber 10 </ b> Z. The difference between the round trip transmission delay amount RZ and the transmission delay amount RZ during the period of 30-
This is a value larger than RZ.

The subscriber communication device 30 and the office communication device 20
Delay Ri required for a frame to reciprocate between
Is the last downlink frame B in the station side communication device 20.
After transmitting the end of d, the delay amount until the transmission delay measurement frame Dui is received is measured, and the delay amount W is obtained by subtracting the delay amount W from the obtained value.

Next, an example of transmission and reception in a frame cycle in which delay measurement is not performed in the phase adjustment channel Du transmitted and received as described above will be described with reference to FIG. As shown in FIG. 4, in the subscriber-side communication device 30 connected via the optical fiber 10i, the station-side communication device 20
After receiving the end of the information frame Bd from the server, the uplink information frame Ba is transmitted with a delay time (RX-Ri).

As described above, the station-side communication device and the subscriber-side communication device have a function of transmitting and receiving the two types of frames Dui and Ba in the phase adjustment channel.
In a certain frame period, delay measurement using Dui is performed.
In other frame periods, information frames Ba are transmitted and received. By measuring the delay intermittently in this way, a band for transmitting information is realized in the phase adjustment channel provided for control. In addition, the method of using the transmission band provided by the above-described method is described using the uplink information channel as an example, but is not limited thereto.

In the present embodiment, an example in which the upstream and downstream transmissions are time-division multiplexed by a single optical fiber has been described as an example, but the upstream and downstream transmissions are independent transmission paths. The present invention can be similarly implemented in a communication system provided with the above, or a communication system in which those independent transmission paths are multiplexed again into one transmission path by frequency multiplexing or the like, and the same effect can be obtained.

(Embodiment 2) Next, Embodiment 2 will be described. The block configuration diagram of the optical communication system according to the second embodiment of the present invention is the same as FIG. 1 as the first embodiment.
The second embodiment of the present invention is different from the first embodiment in that the TDMA circuit for controlling the time division multiplexing of the station side communication device 20 acquires the transfer capacity required by the connected terminal, and , The function of changing the position of the phase adjustment channel back and forth in the frame period is provided.

FIG. 5 shows a communication system having such a configuration, in which the station-side communication device 20 and the subscriber-side communication device 3
2 shows the structure of a channel transmitted / received to / from 0.
With reference to FIG. 5, how the positions of the phase adjustment channels are changed by the TDMA circuits 200 and 300 will be described. If the band required by the terminal is small, the position of the phase adjustment channel Du is arranged in the forward direction, and the downlink information channel Bd is allocated smaller than the uplink information channel Bu. When the band required by the terminal is large, the position of the phase adjustment channel Du is arranged backward, and the downlink information channel Bd is allocated to be larger than the uplink information channel Bu. In this way, by allocating the unused downstream band to the upstream band, it is possible to obtain a transmission capacity that cannot be obtained by fixed allocation.

The transmission positions of the transmission delay measurement frame Dui shown in FIG. 3 and the information frame Ba shown in FIG. 4 are not determined by the absolute positions in the frame period, but are determined from the end of the downstream frame. Determined by relative position.
Therefore, moving the phase adjustment channel does not change the function and operation of these frames.

In the above method, a method of changing the assignment of the information channel only by the band required by the terminal on the station side is shown as an example. It is not limited to only the required band.

[0042]

As described above, according to the present invention, high-speed communication or long-distance communication is performed by intermittently measuring the transmission delay amount and allocating the transmission band to the information channel in a frame period in which the measurement is not performed. Can be performed.

By changing the uplink transmission capacity and the downlink transmission capacity as needed, the transmission capacity can be operated efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a transmission / reception block diagram in the optical communication device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a transmission / reception block diagram in transmission delay measurement according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a transmission / reception block diagram of an information frame in a phase adjustment channel according to the first embodiment of the present invention;

FIG. 5 is a diagram showing a transmission / reception block diagram in the optical communication device according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional example of an optical subscriber communication system.

FIG. 7 is a diagram showing an example of a transmission / reception diagram between a station-side communication device and a subscriber-side communication device in a conventional example of an optical subscriber communication device.

FIG. 8 is a diagram showing an example of a transmission / reception diagram of a phase adjustment channel in a conventional example of an optical subscriber communication device.

[Explanation of symbols]

Reference Signs List 20 Station-side communication device serving as main device 30, 31-3N Subscriber-side communication device serving as slave device 3Z Slave device connected to main device via shortest possible transmission line 3X Via longest possible transmission line Slave device 100, 101 to 10N connected to main device 100, 101 to 10N Optical fiber 10Z Optical fiber to be the shortest possible transmission line 10X Optical fiber to be the longest possible transmission line 110 Star coupler 120 Switch 200 TDMA circuit 201 Electric / optical Converter 300 TDMA circuit 301 Electric / optical converter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Hattori 3-10-1, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Inventor Yuji Hashimoto 4-chome Tsunashima Higashi, Kohoku-ku, Yokohama, Kanagawa Prefecture 3-1 Matsushita Communication Industrial Co., Ltd. (72) Inventor Tetsuya Kawakami 3-1-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture 1-1 Matsushita Communication Industrial Co., Ltd. (72) Inventor Kitachi Nishimine Kohoku, Yokohama-shi, Kanagawa Prefecture 4-3-1 Tsunashima-ku, Ward Matsushita Communication Industrial Co., Ltd. (56) References JP-A-9-205454 (JP, A) JP-A-10-200564 (JP, A) JP-A-7-250152 (JP) JP-A-7-264202 (JP, A) JP-A-7-135507 (JP, A) JP-A-8-340301 (JP, A) JP-A-9-233103 (JP, A) 9-238176 (JP, A) Japanese Patent Application Laid-Open No. 11-41678 (JP, A) Ryuji Sato, Haruki Uchida, A study on delay control method in ATM-PDS system, Proc. IEICE, March 11, 1996, page 408 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04J 3/00-3/26 H04L 5/22-5/26 H04L 7 / 00-7/10 H04L 12/00 H04B 10/00

Claims (4)

(57) [Claims] 1. A communication system having a phase adjustment channel for measuring a transmission delay between the slave device and the main device for performing division multiplex transmission when bidirectionally between the main and slave, the slave
Devices and the measurement of the transmission delay amount between the main device performs intermittent frames, to transmit and receive Oite information frame to the phase adjustment channel at a frame period without receiving the transmission delay measurement frame
Frame phase intermittent adjustment method characterized by allocating a transmission band that. 2. A communication system having a phase adjustment channel for measuring an amount of transmission delay from a slave device to a master device in an upstream frame for performing bidirectional time division multiplex transmission between the master device and a plurality of slave devices. performs an intermittent frame measurement of transmission delay, send a Oite information frame to the phase adjustment channel at a frame period without receiving the transmission delay measurement frame
A frame phase intermittent adjustment method, which comprises allocating a transmission band to be received . 3. The transmission path comprises independent transmission paths each including an upstream transmission path for transmitting a frame from a slave apparatus to a main apparatus and a downstream transmission path for transmitting a frame from the main apparatus to a slave apparatus . 3. The method according to claim 1, wherein the frame phase is intermittently adjusted. 4. The method according to claim 1, wherein the start position of the phase adjustment channel is a relative position from the end of the downstream frame to dynamically change the transmission capacity of the downstream frame as needed. 3. The method according to claim 2, wherein the frame phase is intermittently adjusted.