JP2003298643A - Subscriber transmission system, method for subscriber transmitting, subscriber terminating unit and subscriber data terminal unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a wide band accessing network in which a quality of an STM or an AT with respect to a stream communication and the affinity with a LAN with respect to a burst communication can coexist. <P>SOLUTION: In an accessing network including a subscriber data terminal unit disposed in a subscriber's house and connected to a network of a common carrier, and a subscriber terminating unit for terminating the subscriber data terminal unit via a subscriber' line, a communication time is partitioned by a frame period 7 having a fixed length, and the subscriber's terminating unit and the subscriber's data terminal unit conduct total double communication. The frame period 7 is divided into a time zone of a stream signal communication 8 requested by a periodic transmission of the data, and a time zone of a burst signal communication which does not requests the periodic communication. A time zone for a stream signal packet having a small allowable quantity of a delay or a delay fluctuation is previously assured, preferentially assigned, and in the burst signal packet which allows the delay or the delay fluctuation, a residual time in the period 7 of the fixed length is assigned. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires a stream signal used for bidirectional stream communication, unidirectional stream communication, etc., which requires transmission with less delay and delay fluctuation, and strict delay control in a broadband access network. The present invention relates to a burst signal communication transmission / reception method, a transceiver, a synchronization signal distribution method, and a synchronization signal distribution device.

[0002]

2. Description of the Related Art A conventional communication network is an STM (Synchronous Transfer) created mainly by a communication carrier.
Mode) method and ATM (Asynchronous Transfer Mode)
Based on the system, stream communication such as voice is performed using a fixed length frame structure such as STM or ATM. Moreover, when transmitting a burst signal on STM or ATM, it is often the case that packetization is performed at an IP (Internet Protocol) layer, which is an upper layer of the OSI (Open Systems Interconnection) 7-layer model.

In both STM and ATM, the business operator distributes the same synchronization signal to the entire network, and the device on the subscriber side is subordinately synchronized with the business operator. As described above, the advanced synchronization technology in which the device on the business operator side and the devices on all subscribers are all synchronized is used, and the stability and reliability in stream communication are very high.

On the other hand, Ethernet (registered trademark) (Eth
LAN (Local Area Net) such as Internet (registered trademark)
work) devices, etc. are inexpensive, and are now in widespread use. Ethernet has a good affinity with a PC and is a standard suitable for handling burst signals.

[0005]

[Problem of Coexistence of Stream Communication and Burst Communication] STM, ATM, etc. are networks that reliably control frames and the like, and are suitable for stream communication. On the other hand, in recent years, LAN communication devices composed of variable-length packets such as Ethernet created by the device makers and the like have been spread all over the world, and they are available to subscribers at low cost. Therefore, it is considered necessary to have an access network connectable to these LAN communication devices. On the other hand, although these LAN communication devices are compatible with high-speed burst signal communication, it is impossible in principle to satisfy the quality of current stream communication. Therefore, regarding stream communication, STM
LA for quality like ATM and ATM, and burst communication
The challenge is to realize a broadband access network that can coexist with the N communication device.

[Problem 1 of Sync Signal] In order to perform smooth stream communication without delay and delay fluctuation, it is necessary to synchronize between end-to-end transmitting / receiving devices. In the access network, smooth stream communication can be performed as long as the subscriber terminating device and the subscriber premises device that are subordinately synchronized with the network are in bit synchronization. For that purpose, it is a problem that the subscriber premises equipment reproduces a bit synchronization signal slave-synchronized with the subscriber terminating equipment from the bit string received from the subscriber terminating equipment.

[Problem 2 of Sync Signal] For the same reason as described in [Problem 1 of Sync Signal], smooth stream communication based on a fixed frame length is performed between end-to-end transmitters / receivers. Requires that each device in the network be frame synchronized. That is,
An issue is that the subscriber premises device reproduces the subordinately synchronized frame synchronization signal for the subscriber terminating device that is subordinately synchronized with the network.

[Problem of voice communication on data communication network] In a network such as Ethernet, which has a limited control of delay and delay fluctuation, a signal that should be originally sent as a packet is packetized and sent as a burst signal. A problem arises. For example, in VoIP (Voice over IP), which converts voice into IP packets, and routes and switches over Ethernet, the problem is that the quality is inferior to the current telephone.

[Problem of IEEE 1394] As a conventional technique similar to the present invention, there is IEEE 1394, but it has the following problems.

(Problem of Transmission Rate of IEEE 1394) I
The transmission speed of EEE1394 has a gigabit class standard, but it is about several hundred Mbps as a product currently on the market. Further, the connection form is a bus type connection, and when communication is performed through a device having a low communication speed, the transmission speed of the device becomes a bottleneck, so that the throughput is limited to a low value.

(Problem of IEEE 1394 half-duplex communication) I
The EEE1394 is a half-duplex communication because it is assumed that the communication device will transmit and receive at a distance of about a home, and the communicable distance is limited to several tens of meters. Therefore, it is impossible to realize a gigabit class band expected in the future in an access network of 10 km scale.

(Problem of Variable Length Frame of IEEE 1394) IEEE 1394 is a frame structure in which time zones of stream communication and burst signal communication coexist. This is similar to cell communication of a stream signal in a part of a transmission time zone in ATM communication and transmission, and cell communication of a burst signal in the remaining time zone. It is highly likely. But I
The problem with the IEEE 1394 standard is that the management of frames (called cycles in IEEE 1394) is insufficient. That is, the time zone of the frame fluctuates depending on the time zone of burst signal communication in the frame, and the cycle of the stream signal fluctuates without being constant.

[0013]

[Coexistence of stream communication and burst communication] Since LAN devices that are prevalent in the market are designed for burst communication, it is difficult to guarantee the transmission quality of stream communication. is there. Therefore, a method and apparatus are provided for dividing a time period in which a packet is transmitted into fixed-length frame periods and securing time periods for stream communication and burst communication in the frame. As a result, stream communication that requires delay control and burst communication that does not require delay control can coexist and be transmitted while measuring compatibility with inexpensive LAN products that do not perform delay control.

[Method of Transmitting and Receiving Stream Communication without Delay Fluctuation] As described above, a stream signal having a small permissible delay and delay fluctuation within a fixed-length frame period that periodically divides a packet transmission time period. Prioritize transmission after securing the transmission time zone. By this means, it becomes possible to smoothly transmit the stream signal in the access network without delay and delay fluctuation.

[Bit Synchronization Dependently Synchronized on Network Side] The subscriber premises apparatus reproduces the bit synchronization signal from the bit string of the received signal. As a result, the subscriber premises device is subordinately synchronized with the network side, and smooth stream signal transmission / reception can be performed between end-to-end.

[Extraction of Frame Synchronization Signal and Dependent Synchronization] A fixed-length frame period signal is input to a clock extraction circuit incorporated in a subscriber home device. The clock extraction circuit can extract the frame synchronization signal dependent on the subscriber terminal device. Further, when there is no information signal to be transmitted by the subscriber terminal device, a frame composed of a dummy signal which does not make sense in information is transmitted. This method allows the subscriber premises equipment to
Plays back the frame period that is subordinate to the subscriber terminal device,
It becomes possible to synchronize between end-to-end. Then, it becomes possible to packetize the stream signal and the burst signal and to systematically transmit / receive in accordance with the frame period.

[Control of Uplink Signal] When each subscriber premises device transmits a signal, a control packet describing a desired time zone, data capacity, etc. is transmitted to the subscriber terminating device.
The subscriber terminating device allocates a time period in which transmission is permitted in response to a transmission request from each subscriber home device, and notifies each subscriber home device of the transmission timing. Each subscriber premises device transmits an upstream signal to the subscriber terminating device in accordance with the instructed timing. The subscriber terminating device transfers the received signal to the higher-level network, but when the transmission becomes difficult within the frame, the burst signal is buffered in the buffer device in the subscriber terminating device. However, the stream signal is always transmitted within the allocated frame without buffering. The buffered burst signal is transmitted in the subsequent frames. When it becomes difficult to perform buffering in the subscriber terminating device, a command signal for temporarily stopping transmission is transmitted to the subscriber premises device.

[Sending and receiving control packets] STM and ATM
In order to transmit and receive high-level control information equivalent to that, a control packet is transmitted and received between devices at each frame cycle. With this method, the subscriber terminating device can control the subscriber premises device, and can immediately detect an abnormality in the network or each device. Further, although the invention introduces a fixed length frame, there is no means for recognizing the start or end of the frame. Therefore, the transmitting device arranges the control packet at the beginning or the end of the frame. The reception side device recognizes the position where the control packet is arranged as the start or end point of the frame, and treats the packet arranged in the time zone within the subsequent frame time as the information packet.

[Operation] In the transceiver of the access network of the present invention, a fixed-length frame is introduced by connecting to a gigabit class LAN communication device, a time zone for stream communication is secured in advance, and stream communication is performed. To do. By applying the device that realizes this method to the subscriber terminal device and the subscriber premises device of the access network, the conventional L
It becomes possible to coexist stream communication and burst signal communication without delay and delay fluctuation, which has been difficult with an AN device. Further, it becomes possible to deliver the strict synchronization signal of the communication carrier to the subscriber's home device by using the bit string and frame period of the signal. Further, it becomes possible to deliver to the subscriber a unique synchronization signal managed by the content provider based on the synchronization signal. This makes it possible to distribute and reproduce stream-based contents such as video and audio without using a cache and eliminating delay and delay fluctuation.

[0020]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In all the drawings for explaining the embodiments, those having the same function are designated by the same reference numeral, and the repeated description thereof will be omitted.

FIG. 1 shows an outline of the network configuration of the present invention. An access network 18 is a network composed of the subscriber terminating device 2 in the operator side node 3, the subscriber premises device 6, and a subscriber network 29 connecting both devices. Further, the upper network from the subscriber terminal device is referred to as the upper network 1.

[First Embodiment] FIG. 2 is a block diagram showing the outline of the first embodiment. This embodiment is
The subscriber terminating device 2 is connected to the subscriber premises device 6 via the subscriber line 4 in a single star type.

The access network of this embodiment is
As shown in FIG. 2, a subscriber premises device 6 is arranged in the subscriber premises, and the telecommunications carrier has an access network configuration in which it is connected to the subscriber terminating device 2 via the subscriber line 4.

The protocol will be described. STM and ATM, which reliably control delay and delay fluctuation, are suitable for stream communication of voice and video.
On the other hand, LAN products such as Ethernet are suitable for the currently widely used burst communication of data and the like. LAN products are not designed for stream communication such as voice, but LA products
OS for stream communication using N products
The delay is controlled by layers 3 and above of the I model. Therefore, it is difficult to control the delay and delay fluctuation that occur in Layer 1 and Layer 2.

In the access network, in order to process signals from many subscriber premises equipment without confusion, it is necessary for the carrier to adjust the transmittable timing of the subscriber premises equipment. However, a LAN device or the like does not have such a function, and it is difficult for the communication carrier to adjust the transmission timing of the subscriber home device.

Therefore, in order to solve the above-mentioned problems when introducing communication devices such as LANs which are in the market into the access network, a mechanism for controlling the time slot in which transmission is possible and the delay of stream communication, The purpose is to introduce a mechanism for detecting and creating the synchronization signal.

At present, each telecommunications company has equipment based on the STM system nationwide and provides communication services. Therefore, even if a new system other than the STM system is introduced into the access network, the STM is used in the relay network. It is necessary to go through the device. Burst communication is basically used when each subscriber performs data communication using LAN products. Therefore, STM and L
The fusion of AN is required, and the compatibility of STM and LAN must be taken into consideration in the present invention. Therefore, the fixed-length frame period shown in FIG. 3 is introduced, and the frame is divided into a stream time zone and a burst time zone.

Since the STM communicates in fixed length frames every 125 μsec, the present invention will be described by using a fixed length frame of 125 μsec in which stream communication and burst signal communication coexist. Further, although it is possible to secure a plurality of stream communication time zones within a frame, in the present invention, as shown in FIG. 3, stream communication time zones are concentrated and secured in one place. An example will be described.

In the conventional IEEE 1394, the frame length fluctuates depending on the packet length to be transmitted, and therefore the stream cycle is not fixed. However, the present invention introduces a frame 7 having a fixed time length. Although this frame is composed of a plurality of fixed-length or variable-length packets, the same packet cannot be transmitted across the boundary line between frames. Be sure to complete the transmission of the packet within the frame.

In order to realize a gigabit class access network, the communication method of the present invention is a full-duplex method.

A specific structure of the frame will be described.
First, a downlink signal will be described. As shown in FIG. 3, the frame 7 has a fixed length of 125 μsec, and the information packet cannot be transmitted beyond the boundary line of the frame. Although details will be described later, a packet 2 of control information common to each subscriber is provided at the start or end of the frame.
Insert 1.

The first half portion 8 of the fixed length frame 7 secures a time zone for stream communication such as voice communication with a very small allowable delay, and preferentially allocates it. Also, by allocating to the same position from the beginning of each frame, the stream signal can be transmitted without phase shift. for that reason,
Theoretically, there is no delay or delay fluctuation, and voice communication can guarantee the same quality as the conventional telephone network.

As described above, stream communication of voice, etc.
Be sure to complete the transmission within the frame requested to be transmitted. Two
Do not send a packet beyond the boundaries of two consecutive frames.

However, depending on the device, the order of packets in stream communication may change as long as the packets are transmitted within the same frame.

However, even in the same stream communication, if it is unidirectional stream communication such as the present TV broadcasting, it is possible to divide the packet according to the case and divide it into other frames for transmission. However, in that case, it is necessary to buffer the packet received by the receiving terminal.

On the other hand, in the burst signal communication, a certain degree of delay is allowed, so that the burst signal communication is transmitted in burst within the time zone 9 in the remaining frame in which the stream communication is performed. Also,
Since it is not always necessary to complete the transmission within the assigned frame, it is stored in the buffer device in the subscriber terminating device and within a frame that is later in time depending on the time zone assigned to the burst signal. It is possible to send packets with.

FIG. 4 shows a state in the subscriber terminating device when stream communication signals and burst communication signals come from a plurality of subscribers, and FIG. 5 is a conceptual diagram of a frame configuration process in the subscriber terminating device. Shown in.

As shown in FIG. 4, in the subscriber terminating device 2, the stream signal communication 30 from the subscriber premises device is immediately transferred to the host network 1 within the time period of the stream signal without buffering in the subscriber terminating device. Send to. On the other hand, the burst signal communication 31 from the subscriber home device
Will transmit to the host network within the time zone of the burst signal without passing through the buffer device 28 unless congestion occurs in the subscriber terminal device. When congestion occurs, the burst signal is temporarily stored in the buffer device 28 and transmitted to the host network within the burst signal time zone.

Conversely, the same applies to the stream signal and burst signal transmitted from the upper network to the subscriber terminating device.

When there is no room to store a new burst signal in the buffer device 28, a pause signal for temporarily stopping the transmission is transmitted to the upper network or the subscriber premises device which is the transmission source. Upon receiving the pause signal, the transmission source suspends the transmission of only the burst signal until the pause is released. However, the stream signal is transmitted without pausing.

FIG. 5 shows a state of frame processing in the subscriber terminal device 2. FIG. 3 is a conceptual diagram in which signals transmitted by subscribers A and B are received by a subscriber terminal device and multiplexed. The stream signal 23 of the subscriber A and the stream signal 25 of the subscriber B are always transmitted within the assigned frame. Therefore, as shown in the figure, the stream signals of the subscriber A and the subscriber B are multiplexed in the same frame. In the remaining time zone of the multiplexed frame, there is no time margin for simultaneously transmitting the burst signals of the subscriber A and the subscriber B. Therefore, the burst signal 26 of the subscriber B is stored in the buffer device in the subscriber terminating device, and only the burst signal 24 of the subscriber A is transmitted. In the subsequent frame,
The burst signal of subscriber B is transmitted.

Further, as shown in FIG.
Then, the stream signal communication 30 from the subscriber terminal device 2
Immediately transmits to the subscriber-side terminal 27 within the time zone of the stream signal without buffering in the subscriber premises apparatus 6. On the other hand, burst signal communication from the subscriber terminal device 3
No. 1 transmits to the subscriber side terminal within the time zone of the burst signal without passing through the buffer device 28 unless congestion occurs in the subscriber premises device. When congestion occurs in the subscriber's home device, the burst signal is temporarily stored in the buffer device 28 and transmitted to the subscriber's terminal within the burst signal time zone.

On the contrary, the same applies to the stream signal and the burst signal transmitted from the subscriber side terminal to the subscriber premises equipment.

When the buffer device 28 has no room to store a new burst signal, it transmits a pause signal for temporarily stopping the transmission to the subscriber terminal device or the subscriber terminal which is the transmission source. To do. Upon receiving the pause signal, the transmission source suspends the transmission of only the burst signal until the pause is released. However, the stream signal is transmitted without pausing.

As described above, the stream signal is transmitted while securing the transmission time zone, the burst signal is transmitted using the remaining frame time, and the transmission within the assigned frame does not necessarily have to be completed. A burst signal can transmit a packet within a frame that is later in time, depending on the allocated time slot and the amount of data to be transmitted.

The upstream signal will be described. The frame structure of the upstream signal is the same as that of the downstream signal shown in FIG. However, the subscriber premises device transmits the upstream signal at the transmission timing and the packet size instructed by the subscriber terminating device. This instruction is given using the supervisory control signal.

Next, the control signal will be described. Even if there is no transmission packet, the subscriber terminating device and the subscriber premises device always communicate a monitoring signal in order to monitor the device and the transmission line and to notify the alarm. Using the upstream control signal, the transmission request from the subscriber's home device is superimposed and transmitted to the subscriber terminating device. As the content of the transmission request, the type such as whether the transmission signal is a stream or a burst, the information amount of the transmission signal, and the like are transmitted to the subscriber terminal device. On the other hand, the subscriber terminal device responds to the request signal received from the subscriber home device by
Information such as permission / inhibition of transmission of the subscriber's home device, time zone allocation, and transmission timing is superimposed on the monitoring signal and transmitted to the subscriber's home device.

This monitoring control signal OAM & P (Oper
ation, Administration, Maintenance & Provisionin
As a method of transmitting and receiving g), there is a method of using another wavelength or another channel, but there is a method of arranging in a frame. Specifically, it is placed at the beginning or end of the frame. As a result, the subscriber premises apparatus can recognize the beginning of the frame at the same time as receiving the OAM & P signal.

As means for transmitting the OAM & P signal, there are a method shown in FIG. 3 and two methods shown in FIG. In the method shown in FIG. 3, since it is possible to transmit the OAM & P signal 21 to all the subscriber premises equipment to which the switching equipment is connected, the common information of each subscriber premises equipment is transmitted.
FIG. 7 is a diagram showing a packet structure in which a control signal and a burst signal are multiplexed, and the method shown in FIG. 7 can transmit individual OAM & P signal 14 to each subscriber premises device. As described above, it is possible to transmit common control information and individual control information by properly using the methods of FIGS. 3 and 7.

Next, a method of distributing the synchronization signal will be described. In a LAN, there is no uniform sync signal in the network because each transmitter delivers the sync signal. Therefore, in the access network, in order to perform communication between end-to-end communication devices, it is necessary for the business operator to deliver a unified synchronization signal to the subscriber premises device. Therefore, it is necessary for the business operator side to deliver the synchronization signal to the subscriber home device.

Two methods of distributing the synchronization signal from the operator side apparatus to the subscriber premises apparatus will be described.

The first is a method of reproducing the bit synchronization signal 16 from each bit string 17 of the downlink signal received by the subscriber home device 6 as shown in FIG. The subscriber terminating device owns a strict synchronization signal and creates a bit string based on it. Therefore, the subscriber premises device receives the received bit string 1
The bit synchronization signal 16 is extracted from 7. By extracting the bit string synchronizing signal 16 from the received bit string in this way, it is possible to reproduce the synchronizing signal dependent on the subscriber terminal device in the subscriber premises equipment.

As the second method, there is a means for extracting the synchronization signal 22 from the frame period 7 of the signal received by the subscriber home device 6 as shown in FIG. The subscriber terminating device owns a strict synchronization signal and creates a fixed length frame based on it. Therefore, the subscriber's home device extracts the frame synchronization signal 22 from the received frame period 7.
By extracting the frame synchronization signal 22 from the frame period thus received, it is possible to reproduce the synchronization signal dependent on the subscriber terminal device in the subscriber premises device.

[Second Embodiment] FIG. 10 is a block diagram showing an outline of an access network according to the second embodiment.

Access network 1 of the second embodiment
8 has a double star configuration in which the subscriber premises device 6 is connected to the subscriber terminating device 2 via a concentrator. Here, a configuration using an optical coupler 19 which is multi-branched as shown in FIG. 10 as a concentrator will be described as an example.

Subscriber home device 6 installed in the subscriber's home
Is a PON (Passive Optical Network) configuration including an optical coupler 19 connected to the optical coupler 19 via the subscriber line 4 and a subscriber terminating device 2 connected to the optical coupler via the subscriber line.

In the second embodiment, the method used in the existing PON is used as a lower layer, and the frame structure described in the first embodiment is basically used as a layer above it. Only the points different from the first embodiment will be described below.

Next, the method of transmitting the upstream and downstream signals will be described. Here, the current audio information amount is 64 kbps per channel, and since 8 kHz sampling is performed, the information amount per channel in one packet is 8 bits, that is, 1 byte.

Considering the case of using an Ethernet packet, for example, the minimum payload length is 46 bytes, so 1
It is not possible to compose a packet with bytes, as shown in FIG.
The remaining 45 bytes need to be padded 12 as shown in FIG. This is undesirable because it wastes network resources.

Therefore, in order to effectively use the network resources, a multiplexing device for user multiplexing is arranged in the subscriber terminal device. When the multiplexer receives the upstream and downstream signals, it newly constructs a packet that temporally multiplexes the signal 11 of user # 1 and the signal 20 of user # 2 as shown in FIG. Send to home device.

However, in bidirectional stream communication such as voice, it is necessary to complete the transmission within the assigned frame time period. Therefore, the priority of the multiplexer is to transmit the packet for stream communication in the assigned frame, and do not multiplex and transmit other than the assigned frame.

FIG. 13 shows the relationship between the upstream and downstream signal packets and frames described above. The upper row is OA
The M & P signal 14 is superimposed, and the lower part is the signal 11 of the user # 1.
Also, the packet configuration when the signal 20 of the user # 2 is multiplexed by the user is shown. The subscriber terminating device further multiplexes the packets formed by multiplexing the signals of the respective subscribers to form a fixed-length frame, and transmits the frame to the upper network.

[Third Embodiment] This embodiment relates to a subscriber premises apparatus used in the access network of the present invention.

FIG. 14 corresponds to claim 12 and is a diagram showing a basic configuration of a subscriber premises apparatus. First, the downlink transmitted from the subscriber terminal device to the terminal device will be described.

The signal received by the transmitting / receiving unit 32 from the subscriber terminal device is separated by the signal separating circuit 33 into a stream signal for bidirectional television communication and the like and a burst signal for PC and the like.

The stream signal separated by the signal separation circuit 33 does not pass through a storage device such as a buffer and is transmitted / received by the transmission / reception port 34 in the time zone of the stream in the frame.
From the terminal device to the two-way TV communication or the like.

The burst signal separated by the signal separation circuit 33 is transmitted from the transmission / reception port 35 to the terminal device via the buffer 28-1. However, when congestion occurs, it is stored in the buffer 28-1 until the congestion is released, and after the congestion is released, it is transmitted from the transmission / reception port 35 to a terminal device such as a PC.

Next, an upstream signal transmitted by a terminal device such as a PC or two-way television communication will be described.

An upstream stream signal transmitted from a terminal device such as two-way television communication is received by the transmission / reception port 34, and then input to the signal multiplexing circuit 36 without passing through a storage device such as a buffer, and is assigned and fixed. It is preferentially transmitted to the subscriber terminating device within a long frame.

The upstream burst signal transmitted from a terminal device such as a PC is received by the transmission / reception port 35, and then passes through a storage device such as a buffer 28-2, and is transmitted by a signal multiplexing circuit 36 to the time zone of the burst signal in the frame. Send with. However, when congestion occurs, it is stored in the buffer 28-2 until the congestion is released, and after the congestion is released, the signal multiplexing circuit 36
It is then multiplexed with the stream signal and transmitted to the subscriber terminal device.

FIG. 15 is a diagram showing an embodiment of a subscriber premises apparatus corresponding to claim 15. FIG. 14 is a diagram in which a frame extraction circuit 37 and a frame control circuit 38 are added. Only parts different from the description of FIG. 14 will be described.

The frame extraction circuit 37 is a circuit for extracting a fixed-length frame period from the stream signal received from the subscriber terminal device. Specifically, since there is a packet at the beginning of the frame that declares the start of the frame,
Then the frame period is extracted. The extracted frame period is input to the frame control circuit 38.

The frame control circuit 38 realizes the following two functions. -The packet of the stream signal can move within the time zone of the stream signal in the same frame. However, it does not move to another frame. The packet of the burst signal can be moved and transmitted within the time zone of the burst signal in another frame. Any frame may be sent as long as it is not arranged in the time zone of the stream signal.

A frame control circuit 38 for realizing this function
Transmits information for controlling the transmission of the stream signal and the packet of the burst signal to the signal multiplexing circuit 36, and controls the multiplexing method of the signal multiplexing circuit 36.

FIG. 16 is a diagram showing an embodiment of a subscriber premises apparatus corresponding to claims 17 and 19.

FIG. 14 shows a PLL (Phase Locked Loop).
It is the figure where 39 was added. The PLL 39 is a circuit that extracts a clock from an input signal.

The PLL 39 in the figure extracts the clock subordinately synchronized with the subscriber terminal device by inputting the signal transmitted by the subscriber terminal device. The extracted clock is
The signal is input to the upstream signal multiplexing circuit 36. As a result, it becomes possible to deliver the upstream bit signal based on the clock dependent on the subscriber terminal device to the subscriber terminal device.

[Fourth Embodiment] This embodiment relates to a subscriber terminal device used in the access network of the present invention.

In the present description, the downlink signal and the uplink signal are divided into a diagram of the uplink signal and a diagram of the downlink signal for the sake of easy understanding. In addition, since the current upper network is divided into a stream signal and a burst signal, it is also described in the figure.

FIG. 17 corresponds to claim 14 and is a diagram showing a basic configuration of a subscriber terminal device for transmitting and receiving a downlink signal.

The stream signal and the burst signal received from the host network are transmitted / received by respective transmitting / receiving sections 40,
1 is received and is separated by the signal separation circuits 42 and 43 into signals destined for the respective subscriber premises equipment.

The stream signals do not pass through a storage device such as a buffer, and are preferentially used in the subscriber premises by the signal multiplexing circuits 44 and 45 installed in the respective subscriber premises devices within the time zone of the stream of the assigned frame. Sent to the device. At this time, only the allocated frame should be transmitted.

The burst signal is multiplexed with the stream in the time zone of the burst signal in the frame by the signal multiplexing circuits 44 and 45 installed in each subscriber premises device via the storage device such as the buffer 28-1. Send to the subscriber's home device. However, if congestion occurs, the buffer 28-1
And the signal multiplexing circuits 44 and 4 after the congestion is released.
5, it is multiplexed with the stream signal and transmitted to the subscriber premises equipment.

FIG. 18 is a diagram showing an embodiment of a subscriber terminal device for transmitting and receiving upstream signals.

The upstream signal transmitted from the subscriber's home device is received by the transmission / reception units 46 and 47, and then the signal separation circuit 4
8 and 49, and is separated into a stream signal and a burst signal.

The stream signal is input from the signal separation circuits 48 and 49 to the signal multiplexing circuit 50 without passing through a storage device such as a buffer. The signal multiplexing circuit 50 has a function of multiplexing the packets of the stream communication transmitted by each subscriber home device. The multiplexed signal is immediately transferred to the upper network according to the protocol of the upper network.

The burst signal is once input to the buffer 28-2 and then input to the signal multiplexing circuit 51. this,
The signal multiplexing circuit 51 has a function of multiplexing the packets of the burst signals transmitted by the respective subscriber home devices. The multiplexed signal is transferred according to the protocol of the upper network. However, when congestion occurs, it is stored in the buffer 28-2, and after the congestion is released, it is transmitted from the transmission / reception unit to the upper network.

FIG. 19 corresponds to claim 16. FIG. 17 is a diagram in which a frame extraction circuit 52 and a frame control circuit 53 are added. The downlink signal will also be described first.

The frame extraction circuit 52 is a circuit for extracting a fixed-length frame cycle from the stream signal received from the upper network. Specifically, since there is a packet that declares the start of the frame at the beginning of the frame, the frame cycle is extracted from it. The extracted frame period outputs a signal to the frame control circuit 53 and the upstream frame control circuit 54 shown in FIG.

The frame control circuit 53 realizes the following two functions based on the frame period received from the frame extraction circuit 52. -The packet of the stream signal should move within the time zone of the stream signal in the same frame. However, it does not move to another frame. The packet of the burst signal can be moved and transmitted within the time zone of the burst signal in another frame. If it is not placed in the stream signal time zone,
You can send it in any frame.

The frame control circuit 53 sends information on a method for controlling the transmission of packets of stream signals and burst signals to the signal multiplexing circuits 44, 45, and controls the signal multiplexing circuits 44, 45.

FIG. 20 corresponds to claim 16. FIG. 18 is a diagram in which a frame control circuit 54 is added,
It is a figure regarding an up direction.

The signal output from the frame extraction circuit of FIG. 19 is input to the frame control circuit 54 in the figure. The frame control circuit 54 has the same function as the frame control circuit 53 of FIG. 19 and controls the signal multiplexing circuit 50 for stream signals.

FIG. 21 corresponds to claims 18 and 20. Figure 17 shows the PLL (Phase Locked Loo
It is the figure to which p) 55 was added. First, the downlink signal will be described.

The PLL 55 is a circuit for extracting a clock from the input signal. The clock is necessary for transmitting the upstream and downstream stream signals without delay and delay fluctuation.

This figure will be described. The stream signal received from the host network is input to the PLL 55.
As a result, the PLL 55 can extract the clock that is dependent on the host network. By inputting the clock from the PLL 55 to each of the signal multiplexing circuits 44 and 45 for transmitting to the subscriber's home device, it becomes possible to deliver the bit signal based on the clock dependent on the host network to the subscriber's home device.

FIG. 22 corresponds to claims 18 and 20. Here, the up direction will be described.

Extracted from the PLL55 shown in FIG.
The clock signal is input to the signal multiplexing circuit 50 for stream signals. As a result, the signal multiplexing circuit 50 for the stream signal can transmit the stream signal subordinately synchronized with the upper network to the upper network.

The inventions made by the present inventor are as follows.
Although the specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and needless to say, various modifications can be made without departing from the scope of the invention.

[0100]

As described in detail above, according to the present invention, a gigabit class LA which is distributed in the market at a low price is obtained.
The N communication apparatus is improved by introducing a frame in which stream communication and burst signal communication coexist, introducing a method of distributing a synchronization signal, etc., and installing the same in a subscriber terminating device and a subscriber premises device, thereby providing a conventional ATM. It is possible to construct a gigabit class optical access network at a lower cost than an optical access network using STM. Conventionally, quality has deteriorated in VoIP and the like in which a LAN communication device communicates voice that is stream content because delay or delay fluctuation occurs. However, in the present invention, it is possible to eliminate delays and delay fluctuations and achieve the quality of conventional voice communication by securing a time zone for stream communication in advance. In addition, since the strict synchronization signal managed by the telecommunications carrier is delivered to the subscriber's home device, it becomes easy to deliver the synchronization signal managed by the content provider to the subscriber side, and high quality that does not cause dropped frames, etc. It is possible to deliver contents such as various stream video and audio. In addition, the existing STM has the same frame length as that of the conventional STM and the time zone for stream signals is secured in advance, so that the existing voice communication service can be used. Furthermore, since it is based on LAN technology, it is popular with subscribers. It is possible to use the existing LAN device without renewing.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an access network of the present invention.

FIG. 2 is a diagram showing an access network configuration of the first embodiment.

FIG. 3 is a diagram showing a relationship between a frame period and a stream communication time zone and a burst communication time zone.

FIG. 4 is a diagram showing a transmission concept of stream communication and burst communication in a subscriber terminal device.

FIG. 5 is a diagram showing a method of multiplexing stream communication and burst communication in a subscriber terminal device.

FIG. 6 is a diagram showing a transmission concept of stream communication and burst communication in a subscriber home device.

FIG. 7 is a diagram showing a packet configuration in which a control signal and a burst signal are multiplexed.

FIG. 8 is a diagram showing a flow of extracting a bit synchronization signal from a bit string.

FIG. 9 is a diagram showing a flow of extracting a frame synchronization signal from a frame cycle.

FIG. 10 is a diagram showing an access network configuration of a second embodiment.

FIG. 11 is a diagram showing a configuration in which information signals having a minimum packet length or less are packetized by padding.

FIG. 12 is a diagram showing a packet configuration in which information signals of respective subscribers are user-multiplexed.

FIG. 13 is a diagram showing a relationship with a frame period when transmitting a user-multiplexed packet.

FIG. 14 is a diagram showing a basic configuration of a subscriber home device.

FIG. 15 is a diagram illustrating an example of a subscriber premises device that moves a packet.

FIG. 16 is a diagram illustrating an example of a subscriber premises device that performs subordinate synchronization.

FIG. 17 is a diagram showing a basic configuration (downstream signal) of a subscriber terminal device.

FIG. 18 is a diagram showing a basic configuration (uplink signal) of a subscriber terminal device.

FIG. 19 is a diagram showing an example (downlink signal) of a subscriber terminal device that moves a packet.

FIG. 20 is a diagram illustrating an example (uplink signal) of a subscriber terminal device that moves a packet.

FIG. 21 is a diagram illustrating an example (downlink signal) of a subscriber terminal device that performs subordinate synchronization.

FIG. 22 is a diagram illustrating an example (uplink signal) of a subscriber terminal device that performs subordinate synchronization.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper level network, 2 ... Subscriber termination device, 3 ... Operator side node, 4 ... Subscriber line, 6 ... Subscriber premises device, 7 ...
Frame period, 8 ... Time period for stream communication, 9 ... Time period for burst signal communication, 10 ... Header, 11 ... User # 1 data, 12 ... Padding, 13 ... Minimum packet length, 14 ... OAM & P, 15 ... Burst signal, 16 ...
Bit synchronization signal, 17 ... Bit string of received signal, 18 ... Access network, 19 ... Optical coupler, 20 ... User #
2 data, 21 ... Control information (OAM & P), 22 ... Frame synchronization signal, 23 ... Stream signal of subscriber A, 2
4 ... Burst signal of subscriber A, 25 ... Stream signal of subscriber B, 26 ... Burst signal of subscriber B, 27 ... Subscriber side terminals, 28, 28-1, 28-2 ... Buffer device, 29 ... Subscriber network, 30 ... Stream communication, 31 ... Burst communication, 32 ... Transceiver unit, 33 ... Signal separation circuit, 34, 35 ... Transceiver port, 36 ... Signal multiplexing circuit, 37 ... Frame extraction circuit, 38 ... Frame control circuit, 39 ... PLL, 40 ... Transceiver (stream), 4
1 ... Transceiver (burst), 42 ... Signal separation circuit (stream), 43 ... Signal separation circuit (burst), 44, 4
5 ... Signal multiplexing circuit, 46, 47 ... Transceiver, 48, 49
... signal separation circuit, 50 ... signal multiplexing circuit (stream),
51 ... Signal multiplex circuit (burst), 52 ... Frame extraction circuit, 53, 54 ... Frame control circuit, 55 ... PLL

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K030 GA03 GA13 HA08 HB01 HB28                       HC01 HD03 JA07 JL08 KX11                       LC11 MA04 MB02 MB15                 5K033 AA01 CB06 CB17 CC02 DA01                       DB13 DB16 DB18

Claims (20)

[Claims] 1. An access network, which is arranged in a subscriber's premises and comprises a subscriber premises device connected to a network of a communication carrier, and a subscriber terminating device terminating the subscriber premises device via a subscriber line. In the above, the communication time is divided into fixed-length frame periods, and the subscriber terminating device and the subscriber premises device are subscriber transmission systems for performing full-duplex communication. It is divided into a stream signal communication time zone that requires transmission and a burst signal communication time zone that does not require periodic transmission, and the time zone for the stream signal packet with a small delay or delay fluctuation tolerance is set in advance. Within the frame period of fixed length, for the burst signal packet that is secured and preferentially allocated, and delay or delay fluctuation is allowed. Subscriber transmission system and allocates the remaining time period. 2. When it becomes difficult to store an upstream burst signal packet received from the subscriber premises device in the storage device in the subscriber terminating device, the subscriber terminating device is configured to connect the subscriber terminating device to the subscriber. A command signal for temporarily stopping the transmission of the upstream burst signal packet is transmitted to the customer premises device, and the subscriber premises device temporarily suspends the transmission of the upstream burst signal packet until it is canceled when the command signal is received. 2. The subscriber transmission system according to claim 1, wherein communication is continued without limitation with respect to upstream signal packets from the subscriber premises equipment to the subscriber terminating equipment. 3. When it becomes difficult to store the downlink burst signal packet received from the subscriber terminating device in the storage device in the subscriber premises device, the subscriber premises device uses the subscriber premises device. A command signal for temporarily stopping the transmission of the downlink burst signal packet is transmitted to the user terminating device, and the subscriber terminating device temporarily stops the transmission of the downlink burst signal packet until it is canceled when the command signal is received. 2. The subscriber transmission system according to claim 1, wherein the communication is continued without limitation with respect to the downstream signal packet from the subscriber terminating device to the subscriber premises device. 4. When it becomes difficult to store a downlink burst signal packet received from a higher-order network in the storage device in the subscriber-termination device, the subscriber-termination device is provided to the higher-order network. 2. A command signal for temporarily stopping the transmission of a downstream burst signal packet is transmitted, but the communication is continued without limitation regarding the downstream signal packet from the upper network to the subscriber terminating device. Subscriber transmission system. 5. When it becomes difficult to store an upstream burst signal packet received from the subscriber side terminal device in the storage device in the subscriber premise device, the subscriber premise device is A command signal for temporarily stopping the transmission of upstream burst signal packets is transmitted to the subscriber side terminal device, but communication is continued without limitation for upstream signal packets from the subscriber side terminal device to the subscriber termination device. The subscriber transmission system according to claim 1, characterized in that. 6. At the beginning or end of each frame,
2. The subscriber transmission system according to claim 1, wherein the control packet means the start or end of a frame, and a control packet different from the information signal is arranged. 7. An access network comprising a subscriber premise device arranged in the subscriber premise and connected to a network of a telecommunications carrier, and a subscriber terminating device terminating the subscriber premise device via a subscriber line. In the above, the communication time is divided into fixed-length frame periods, and the subscriber terminating device and the subscriber premises device are subscriber transmission methods for performing full-duplex communication. It is divided into a stream signal communication time zone that requires transmission and a burst signal communication time zone that does not require periodic transmission, and the time zone for the stream signal packet with a small delay or delay fluctuation tolerance is set in advance. For the burst signal packet that is secured and preferentially allocated, and delay or delay fluctuation is allowed, for the remaining time period within the fixed-length frame period Subscriber transmission method and assigns. 8. When it becomes difficult to store the upstream burst signal packet received from the subscriber premises device in the storage device in the subscriber terminating device, the subscriber terminating device is configured to A command signal for temporarily stopping the transmission of the upstream burst signal packet is transmitted to the customer premises device, and the subscriber premises device suspends the transmission of the uplink burst signal packet until it is canceled when the command signal is received. The subscriber transmission method according to claim 7, wherein the communication is stopped and the upstream signal packet from the subscriber premises equipment to the subscriber terminating equipment is continued without limitation. 9. When it becomes difficult to store the downlink burst signal packet received from the subscriber terminating device in the storage device in the subscriber premises device, the subscriber premises device uses the subscriber premises device. A command signal for temporarily stopping the transmission of the downlink burst signal packet is transmitted to the user terminating device, and the subscriber terminating device temporarily stops the transmission of the downlink burst signal packet until it is canceled when the command signal is received. The subscriber transmission method according to claim 7, wherein the communication is continued without limitation with respect to the downstream signal packet from the subscriber terminating device to the subscriber premises device. 10. When it becomes difficult to store a downlink burst signal packet received from a higher-order network in the storage device in the subscriber-termination device, the subscriber-termination device is provided to the higher-order network. 8. The subscription according to claim 7, wherein a command signal for temporarily suspending the transmission of the downlink burst signal packet is transmitted, and communication is continued without limitation regarding the downlink signal packet from the upper network to the subscriber terminating device. Person transmission method. 11. When it becomes difficult to store an upstream burst signal packet received from the subscriber side terminal device in the storage device in the subscriber premise device, the subscriber premise device is A command signal for temporarily stopping the transmission of the upstream burst signal packet is transmitted to the subscriber side terminal device, and the communication is continued without limitation with respect to the upstream stream signal packet from the subscriber side terminal device to the subscriber terminal device. The subscriber transmission method according to claim 7, characterized in that 12. The subscriber premises equipment in the subscriber transmission system according to claim 1, wherein the means for connecting to the subscriber side terminal device, and the stream signal packet transmitted by the subscriber side terminal device, Means for transmitting to the subscriber terminating device within the time period of the stream communication without storing in a storage device in the subscriber premises device, and burst non-congestion regarding burst signal packets transmitted by the subscriber side terminal device. When it occurs, it is transmitted to the subscriber terminating device in the burst signal communication time zone, and when congestion occurs, it is stored in the storage device in the subscriber premises device and after the congestion is released, the subscriber termination in the burst signal communication time zone. A means for transmitting to the device, and a stream signal packet transmitted by the subscriber terminating device stored in a storage device in the subscriber premises device. Means for transmitting to the subscriber side terminal device within the time period of the stream communication without a burst signal packet transmitted by the subscriber terminal device, in the time period of the burst signal communication when no congestion occurs Means for transmitting to the terminal device on the subscriber side, storing in the storage device in the device at the subscriber's premises when congestion occurs, and transmitting to the terminal device on the subscriber side during the time period of the burst signal communication after the congestion is released; A subscriber premises device characterized by: 13. When transmitting a signal to the subscriber terminating device, a control signal for requesting a time zone required for transmission or requesting transmission permission is transmitted to the subscriber terminating device, and the subscriber terminating device is provided. Based on the control signal received from the device,
13. The subscriber premise device according to claim 12, which transmits a stream signal packet and a burst signal packet to the subscriber terminal device. 14. The subscriber terminating device in the subscriber transmission system according to claim 1, wherein said request signal is received from each of said subscriber premises devices connected via said subscriber line. Means for transmitting a control signal for allocating a transmission permission of the stream signal and the burst signal, a transmission timing and a transmittable time zone to a subscriber premises apparatus, and a stream signal packet received from the subscriber premises apparatus, said subscriber terminating apparatus Means for transferring in frame synchronization with a fixed-length frame cycle of the upper network according to a protocol of the upper network to a higher network connected to the subscriber terminating device without being stored in a storage device therein; Regarding the burst signal packet transmitted by the home device, when congestion does not occur, the upper network According to the protocol of immediately transfer to the upper network, when congestion occurs, stored in the storage device in the subscriber terminating device and means for transmitting to the upper network according to the protocol of the upper network after decongestion, and from the upper network Means for preferentially transmitting the received stream signal packet to the subscriber premises equipment within the time zone for the stream signal without storing the received stream signal packet in the storage device in the subscriber terminating device; Regarding the burst signal packet, when congestion is not generated, it is transmitted to the subscriber premises device in the time zone of the burst signal communication, and when congestion occurs, it is stored in the storage device in the subscriber termination device and the burst signal communication Means for transmitting to the subscriber's home device during the time zone , The subscriber terminating device, characterized in that it comprises a. 15. A transparent stream signal packet can be moved within the same frame, and a transparent burst signal packet can be moved within a frame and across frames. 13. The subscriber according to claim 12, wherein the stream signal packet is arranged in the time zone of the stream signal even after the movement, and the burst signal packet is arranged in the time zone of the burst signal after the movement. Home device. 16. A transparent stream signal packet can be moved within the same frame, and a transparent burst signal packet can be moved within a frame or across frames. 15. The subscriber according to claim 14, wherein the stream signal packet is arranged in the stream signal time zone even after the movement, and the burst signal packet is arranged in the burst signal time zone even after the movement. Termination device. 17. The subscriber premises equipment extracts the clock of the subscriber terminating equipment based on the downlink signal transmitted by the subscriber terminating equipment, and the subscriber premises equipment transmits the clock to the subscriber terminating equipment.
13. The clock is slave-synchronized.
The subscriber premises equipment described in. 18. The subscriber terminating device extracts the clock of the upper network based on the downlink signal transmitted by the upper network, and the subscriber terminating device synchronizes the clock with the upper network. 15. The subscriber terminating device according to claim 14. 19. The frame of the subscriber terminating device is extracted by the subscriber premises device based on the frame period of the downlink signal transmitted by the subscriber terminating device, and the subscriber premises device sends the frame to the subscriber terminating device. 13. The subscriber premise device according to claim 12, wherein the frames are subordinately synchronized. 20. Based on the frame period of the downlink signal transmitted by the upper network, the subscriber's home device extracts a frame of the upper network, and the subscriber's home device synchronizes the frame with the upper network. The subscriber terminating device according to claim 14, characterized in that.