WO2008080350A1

WO2008080350A1 - Method and device for adjusting bandwidth in optical access network dynamically and system thereof

Info

Publication number: WO2008080350A1
Application number: PCT/CN2007/071366
Authority: WO
Inventors: Huafeng Lin
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-12-29
Filing date: 2007-12-28
Publication date: 2008-07-10
Also published as: CN101212255A; CN101212255B

Abstract

A method and device for adjusting the bandwidth in optical access network dynamically, the method includes the following steps: establishing the fixed bandwidth downline channel and the dynamic bandwidth downline channel between each optical line terminal (ONU) and the optical network unit (OLT), enabling the dynamic bandwidth downline channel when the OLT detecting the downline service message sent to the ONU exceeds the transmission ability of the fixed bandwidth downline channel of the ONU; sending the downline service message to the ONU through the fixed bandwidth downline channel and the dynamic bandwidth downline channel. An optical line terminal, an optical network unit and an optical access network system are also provided.

Description

Method, device and system for dynamically adjusting bandwidth of optical access network

Technical field

The present invention relates to the field of optical access networks, and in particular, to a method, device and system for dynamically adjusting bandwidth of an optical access network. Background of the invention

As the demand for user bandwidth continues to increase, traditional copper broadband access systems are increasingly facing bandwidth bottlenecks. At the same time, the fiber-optic communication with huge bandwidth capacity is becoming more and more mature, and the application cost is decreasing year by year, which makes the application demand of FTTx in the access network more beneficial. In FTTx, according to the distance between the fiber and the user's application, it can be divided into Fiber To The Home (FTTH) and Fiber To The Node (FTTN). FTTH is more suitable for deployment in new, fiber-optic homes, and FTTN is more suitable for deployment in small areas where fiber is pulled into a residential area or building, using twisted pair or Category 5 or copper shaft cables.

In FTTH, fiber is deployed in every home or office to achieve full fiber access. Currently, point-to-multipoint (P2MP) time division multiplexing passive optical network (Time Division Multiplexing-Passive Optical Network) is used. , TDM-PON), such as Broadband Passive Optical Network (BPON), Ethernet Passive Optical Network (EPON), Gigabit Passive Optical Network (Gigabit Passive Optical Network) , GPON) and so on. Figure 1 shows the function of a typical TDM-PON: A passive optical network consists of an Optical Line Terminal (OLT) at the Central Office (CO), and an optical distribution network (Optical). Distribution Network, ODN) and many Optical Network Units (ONUs). TDM-PON adopts time division multiplexing in the downlink With the downlink bandwidth, the uplink bandwidth is multiplexed in each uplink ONU by using Time Division Multiple Access (TDMA). At present, although BPON and EPON have been applied in large scale in areas such as Sakamoto and North America, GPON is gradually entering the commercial P-segment, but the TDM-PON network structure has inherent disadvantages, such as large power branch loss of the branch. It is difficult to send and receive uplink high-speed bursts, which makes it difficult to overcome the technical difficulties of bandwidth upgrade and fiber fault location.

In FTTN, the optical fiber is used as the medium for the underlying data transmission, and is pulled to each residential area or commercial area node, and then the equipment such as an Ethernet switch, Digital Subscriber Line Access Multiplexer (DSLAM) is used. Convergence, using traditional twisted pair, copper shaft cable or Category 5 line to enter the home, thereby reducing operation and maintenance costs and extending communication distance. At present, FTTN is mainly implemented in a point-to-point manner. Point-to-point transmission has the advantages of simple structure, easy upgrade and transparent protocol. However, due to the low integration of point-to-point transceivers, the utilization of fiber bandwidth is low and the system capacity is limited. Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) technology is increasingly causing people due to efficient fiber utilization, huge bandwidth capacity, and larger system capacity. s concern.

Figure 2 shows the function of implementing FTTN using WDM-PON. However, when implementing FTTN, the network design can only use the maximum bandwidth requirement of the service as the network design standard. The bandwidth requirement is only the service dimension, that is, the commercial area needs 5Gbps downlink transmission bandwidth at the busiest time, and the busiest time in the residential area. Requires 2.5 Gbps downlink transmission bandwidth, then the laser transmitter (Txn) corresponding to ONUn and the ONUn laser receiver (Rx) on the OLT must be designed at a rate of 5 Gbps on the OLT, and the laser corresponding to ONU1 on the OLT The transmitter (Txl) and the Rx of ONU1 must be designed at a rate of 2.5 Gbps. In fact, in addition to the service dimension, bandwidth requirements also have time dimensions. For example, the business district has a large bandwidth requirement (5 Gbps) during the day, but only a basic bandwidth at night. Demand (1.25Gbps or less is enough), holidays are also very different from normal working days; similarly, in the daytime, most people go to work in the daytime, only need a 1.25Gbps or even lower Bandwidth, while at night, the required bandwidth has risen sharply, requiring 2.5 Gbps and higher bandwidth requirements, and holidays are also very different from normal working days.

In response to the above problems, a geographical bandwidth allocation protocol has emerged. The basic idea is to use a tunable wavelength laser emitter, called a tunable laser, to combine WDM with TDM, and to schedule all tunable globally. The laser, for each TDM-PON service, achieves geographic bandwidth allocation. For example, the bandwidth required for the home network in the daytime is small, and the bandwidth of the commercial area is very tight. At this point, part of the bandwidth of the tunable laser for the home premises network can be dispatched to users in the commercial area, while in the evening, The opposite is scheduled, thereby realizing geographical bandwidth allocation and improving the efficiency of using network resources.

As shown in Figure 3, there are several tunable lasers in the central office. Each tunable laser can be scheduled globally to serve any TDM-PON behind the remote node 1. Since each tunable laser can serve any ONU in any TDM-PON network by time division multiplexing, the bandwidth can be dynamically adjusted according to different bandwidth requirements of different ONUs in different time periods. This technique uses two layers of time division multiplexing nesting: First, each tunable laser is time division multiplexed between each TDM-PON network; on this basis, each tunable laser is between ONUs within each TDM-PON network. Perform another time division multiplexing. The scheduling mechanism will be very complicated due to the use of two layers of time division multiplexing nesting. In addition, since the tunable laser is expensive, the cost of such a technical solution will also be quite expensive. Summary of the invention

In order to improve the flexibility of the dynamic bandwidth adjustment, the cost reduction, the resource saving, the network, and the scheduling mechanism, the embodiment of the present invention proposes a method for dynamically adjusting the bandwidth of the optical access network. The method can establish a fixed bandwidth downlink channel and a dynamic bandwidth downlink channel between each ONU and the OLT, and perform the following steps:

When the OLT detects that the downlink service information sent to the ONU exceeds the transmission capacity of the fixed bandwidth downlink channel of the ONU, the dynamic bandwidth downlink channel is enabled;

The OLT sends the downlink service information sent to the ONU to the ONU through the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel.

An embodiment of the present invention further provides an optical line terminal OLT, where the optical line terminal includes a transceiver controller, n fixed wavelength laser emitters respectively corresponding to n ONUs connected to the OLT, and a tunable wavelength laser emitter The transceiver controller includes a traffic detection module, a downlink service information distribution module, a dynamic bandwidth downlink channel transmission control module, and a fixed bandwidth downlink channel transmission control module;

The traffic detection module is configured to detect whether the downlink service information to be sent to the ONU exceeds the transmission capability of the fixed bandwidth downlink channel of the ONU, and if yes, the traffic detection module sends the traffic distribution control command and the downlink service information to the The downlink service information offloading module; otherwise, the downlink service information is sent to the downlink service information offloading module; the downlink service information offloading module is configured to: when receiving the offloading control instruction sent by the traffic detecting module, according to The downlink service information sent by the traffic detection module is used to offload the downlink service information to be sent to the ONU, and obtain a part that is sent through the fixed bandwidth downlink channel and a part that is sent through the dynamic bandwidth downlink channel; or, when not received. When the shunt control command sent by the traffic detection module is sent, the downlink service information from the traffic detection module is used as a part that is sent through the fixed bandwidth downlink channel;

The fixed bandwidth downlink channel sending control module is configured to modulate, by the downlink service information offloading module, a part of the fixed bandwidth downlink channel to be an optical signal of a fixed wavelength laser transmitter wavelength corresponding to the ONU, and send the optical signal ; The fixed wavelength laser transmitter is configured to generate a corresponding fixed wavelength laser; the dynamic bandwidth downlink channel transmission control module is configured to adjust a wavelength of the adjustable wavelength laser transmitter, and send the downlink service information shunt module And partially transmitting the optical signal transmitted by the dynamic bandwidth downlink channel to the wavelength of the tunable wavelength laser transmitter and transmitting the optical signal;

The tunable wavelength laser emitter is used to generate a tunable wavelength laser having a wavelength range of FSR + λ 到 to FSR + λη.

An embodiment of the present invention provides an optical network unit ONU, where the ONU includes a first fixed wavelength laser receiver Rx1 having a wavelength of λί and a second fixed wavelength laser receiver Rx2 having a wavelength of FSR+λ··, wherein the Rx1 is used. The downlink service information is received from a downlink channel having a wavelength of λ, and the Rx2 is used to receive downlink service information from a wavelength of the FSR+λζ downlink channel.

An embodiment of the present invention further provides an optical access network system, including:

a transceiver controller, at least one fixed wavelength laser transmitter and a tunable wavelength laser transmitter, and at least one fixed bandwidth downlink channel receiving module and at least one dynamic bandwidth downlink channel receiving module;

The transceiver controller includes a traffic detection module, a downlink service information offload module, a dynamic bandwidth downlink channel transmission control module, and a fixed bandwidth downlink channel transmission control module;

The traffic detection module is configured to detect whether the downlink service information to be sent to the fixed bandwidth downlink channel receiving module exceeds the transmission capability of the fixed bandwidth downlink channel receiving module, and if yes, the traffic detection module sends the traffic off control command and the downlink The service information is sent to the downlink service information distribution module;

The downlink service information offloading module is configured to offload downlink service information to be sent to the fixed bandwidth downlink channel receiving module according to the traffic distribution control command and the downlink service information sent by the traffic detection module, to obtain a downlink channel through the fixed bandwidth. The part sent and the part sent through the dynamic bandwidth downlink channel; The fixed bandwidth downlink channel transmission control module is configured to modulate the portion transmitted through the fixed bandwidth downlink channel into an optical signal of the fixed wavelength laser transmitter wavelength; the fixed wavelength laser transmitter is configured to generate a corresponding fixed wavelength The dynamic bandwidth downlink channel transmission control module is configured to adjust a wavelength of the tunable wavelength laser emitter, and modulate the portion transmitted through the dynamic bandwidth downlink channel to the wavelength of the tunable wavelength laser emitter signal;

The tunable wavelength laser emitter is for generating a tunable wavelength laser having a wavelength range of FSR + λ 到 to FSR + λ η;

The fixed bandwidth downlink channel receiving module is configured to receive an optical signal from a fixed wavelength laser transmitter;

The dynamic bandwidth downlink channel receiving module is configured to receive an optical signal from a tunable wavelength laser transmitter.

Beneficial effects:

Since a fixed bandwidth downlink channel and a dynamic bandwidth downlink channel are established between each ONU and the OLT, one of which is an exclusive channel and the other is a shared channel, each ONU has an exclusive wavelength channel to ensure a minimum bandwidth, and also The dynamic extra bandwidth can be provided according to the size of the downlink service information of each ONU. Since the dynamic bandwidth downlink channel is shared by all ONUs, the resource utilization rate of the present invention is high, and since only a small number of adjustable lasers are required, the cost of implementing the present invention is relatively low and cost-effective.

Because the downlink service information of the fixed bandwidth downlink channel load capability of the ONU exceeds the ONU, the method of offloading through the dynamic bandwidth downlink channel (tunable laser) is adopted, so that the scheduling mechanism is single and flexible. BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic diagram of the function of a passive optical network in the prior art;

2 is a schematic diagram of a function of implementing FTTN by using WDM-PON in the prior art; FIG. 3 is a schematic diagram of bandwidth dynamic allocation using WDM and TDM in the prior art; FIG. 4 is a dynamic adjustment of bandwidth of a single node overload according to an embodiment of the present invention; Schematic diagram of WDM-PON for fault protection;

5 is a schematic diagram of a FSR periodicity of a wavelength routing module AWG in the prior art; FIG. 6 is a schematic diagram of a function of a wavelength routing module AWG in the prior art;

Figure 7 is a flow chart of Embodiment 1 of the present invention;

8 is a schematic diagram of a WDM-PON of a bandwidth dynamic adjustment and a fault protection function of a multi-node overload according to an embodiment of the present invention;

Figure 9 is a flow chart of Embodiment 2 of the present invention;

10 is a schematic diagram of a WDM-PON with a fault protection function of an optical access network according to an embodiment of the present invention;

11 is a flow chart showing the fault protection of the tunable laser of the embodiment of the present invention with a wavelength between 1 and (FSR+n);

12 is a flow chart showing the fault protection between the wavelengths of the tunable lasers (FSR+λΙ)-(FSR+λη) according to an embodiment of the present invention;

13 is a structural diagram of an apparatus for dynamically adjusting bandwidth and fault protection of an optical access network according to an embodiment of the present invention;

FIG. 14 is a structural diagram of an optical access network apparatus according to an embodiment of the present invention.

Mode for carrying out the invention

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a Limitation of the invention.

In order to provide a dynamic bandwidth adjustment function for each FTTN node, the embodiment of the present invention can establish a fixed bandwidth downlink channel and a dynamic bandwidth downlink channel between each ONU and the OLT, where the fixed bandwidth downlink channel is used to provide a fixed bandwidth for the ONU. , called the first channel; dynamic bandwidth downlink channel provides dynamic bandwidth for the ONU, called the second channel. In the period when the downlink load is small, the downlink data does not need to be sent through the second channel, and the ONU only receives the downlink data in the first channel; when the traffic is busy, the downlink load exceeds the transmission capability of the first channel, and the OLT will be based on the buffer. Monitor the result or the request of the ONU, and enable the second channel in time to dynamically meet the bandwidth requirements of the ONU. The first channel is exclusive to each ONU, and the second channel is shared by all ONUs in the entire PON. The OLT can perform time-division multiplexing scheduling of the second channel in a global scope according to requirements.

As shown in Figure 4, the transceiver between the OLT and the ONU1 forms the first channel of the ONU1 through the transceiver with the wavelength λΐ, and the transceiver between the OLT and the ONU2 is formed by the wavelength λ2.

The first channel of ONU2, and the transceiver with wavelength λη between OLT and ONUn form the first channel of ONUn. These first channels are exclusive to each ONU, providing a fixed bandwidth for each ONU. The principle of the periodic characteristics of the Free Spectrum Range (FSR) of the Wavelength Routing Module (AWG) is shown in Figure 5. The wavelength λ is the abscissa, and the spectral characteristics are periodically distributed. The period is FSR. In order to enable each ONU to time-multiplex the second channel, the present invention fully utilizes the FSR periodic characteristics of the wavelength routing module (AWG), adopts a tunable laser on the OLT, and the tunable laser can adjust the wavelength through time. An ONU communication, thereby realizing the second channel shared by all ONUs. The wavelength of the tunable laser can be adjusted to any wavelength between (FSR + λ Ι ) ~ (FSR + λ η).

As shown in FIG. 6, the FSR periodic principle of an lxn AWG module is: when inputting n optical signals of wavelengths λ1~λη at the input end thereof, outputting an optical signal with a wavelength of λΐ on the first output end. , at the second output, output an optical signal with a wavelength of λ2... at the η One output outputs an optical signal of wavelength λη; according to the FSR periodicity of the AWG, when an optical signal of wavelength (NxFSR+λΙ) is input to the input of the AWG, it will also be output on the first output of the AWG. Similarly, (NxFSR+λ optical signal will be output on the first output of the AWG, 1 ≤ ≤ η, N is an integer > 0.

The OLT's transceiver controller has a traffic monitoring and statistics function. The relevant part of the function is called the traffic monitoring and statistics module. It can monitor and count the downlink data traffic from the upper-level device that needs to be sent to each ONU. If the statistics show that the downlink data traffic sent to the i-th ONU (denoted as ONUi) exceeds the bandwidth capacity of the first channel exclusive to the ONU, the OLT's transceiver controller will control the tunable laser and enable the second channel to share the ONU's The load of one channel, so as to achieve the purpose of dynamic bandwidth adjustment. For example, during the daytime, the ONUn service in the commercial area is busy, and the first channel cannot meet the downlink bandwidth requirement of the user. At this time, the traffic monitoring and statistics module detects that the data traffic sent to the ONUn exceeds the transmission capability of the Txn, and The transceiver of the OLT sends an alarm. After the OLT's transceiver controller receives the alarm, it will enable the tunable laser and adjust its wavelength to (FSR+ n). At the same time, the OLT will notify ONUn through the management message to prepare for receiving downlink data on both Rxl and Rx2. After ONUn is ready, it will send an acknowledgement message to the OLT. After receiving the acknowledgment message, the OLT transceiver controller divides the downlink data from the upper-level device that needs to be sent to the ONUn into two parts according to a certain load balancing algorithm, and the part is sent to the transmission buffer of the tunable laser and passes through The optical signal of wavelength (FSR+λη) is sent to ONUn, and the other part is sent to the transmission buffer of Txn and transmitted to ONUn by the optical signal of wavelength λη.

Example 1

Referring to FIG. 4 and FIG. 7, the following takes the first channel overload of the OUNn node as an example to illustrate the method for dynamically adjusting the bandwidth of the optical access network. The specific steps are as follows: Step 101: Transceiver controller of the OLT The traffic monitoring and statistics module detects that the data traffic sent to the ONUn exceeds the transmission capacity of its first channel, and sends an alarm to the OLT. Transceiver controller.

Step 102: The OLT receiving and receiving controller receives an alarm, and the OLT sends a management message to notify ONUn to prepare for receiving downlink data simultaneously on Rxl and Rx2.

Step 103: ONUn receives the management message, is ready to receive data from Rxl and Rx2, and sends an acknowledgement message to the OLT.

Step 104: After receiving the acknowledgement message sent by the ONUn, the OLT enables the tunable laser and adjusts its wavelength to (FSR+λη λ) while the OLT transceiver controller sends the data to the ONUn according to a certain load balancing algorithm. Divided into two parts, part of the data is modulated into the optical signal of wavelength (FSR+λη), and the modulated optical signal is sent to the coupler, and the other part of the data is modulated into the optical signal of wavelength λη, AWG1 will receive The downstream optical signals of the wavelengths λ1 to λη carrying the data are multiplexed into one optical signal and also sent to the coupler.

Step 105: The coupler sends the received mixed optical signal to the AWG3 through the circulator. The circulator transmits the optical signal from the coupler to the AWG3 at the far end node on the one hand and the optical signal from the AWG3 to the AWG2 on the other hand.

Step 106: AWG3 demultiplexes the received mixed optical signal, sends an optical signal with a wavelength of λΐ to ONU1, and transmits an optical signal with a wavelength of λ2 to ONU2, ..., and the light with a wavelength of λη The signal is sent to ONUn, and the modulated optical signal of the wavelength (FSR + λη) from the tunable laser is sent to ONUn.

Step 107: ONUn receives the optical signals carrying the data from Rx1 and Rx2, respectively, and the other ONUx receives the optical signals carrying the data from Rx1.

ONUn can receive data carried on the wavelength λη and receive data carried on the wavelength (FSR+λη), thereby expanding the downstream bandwidth of ONUn.

The OLT transceiver controller enables the tunable laser to provide the second channel for the ONUn to transmit the downlink data, and then continues to monitor the data traffic from the upper-level device that needs to be sent to the ONUn. If the statistics of the traffic monitoring and statistics module show the first channel, Txn itself can do this When the data traffic is sent, the Txn shunt and the tunable laser are stopped, and a control message is sent to notify ONUn to turn off Rx2. Example 2

Referring to FIG. 8 and FIG. 9, the method for realizing the dynamic adjustment of the bandwidth of the optical access network is described by taking the simultaneous overload of the first channel of the two commercial area nodes ONU2 and ONUn as an example, and the specific steps are as follows:

Step 201: The traffic monitoring and statistics module of the transceiver controller of the OLT detects that the data traffic sent to the ONU2 and the ONUn exceeds the transmission capacity of the first channel, and sends an alarm to the transceiver controller of the OLT.

Step 202: The OLT receiving and receiving controller receives an alarm, and the OLT sends a management message to notify ONU2 and ONUn to prepare for receiving downlink data simultaneously on Rxl and Rx2.

Step 203: ONU2 and ONUn receive the management message, are ready to receive data from Rxl and Rx2, and send an acknowledgement message to the OLT.

Step 204: After receiving the acknowledgement packet sent by ONU2 and ONUn, the OLT enables the tunable laser. At the same time, the OLT transceiver controller divides the data to be sent to ONU2 and ONUn into two parts according to a certain load balancing algorithm, and a part of the data is modulated into optical signals of wavelengths (FSR+ 2 ) and (FSR+λη ) (tunable wavelength laser) The wavelength will be controlled by the transceiver controller, the time division is switched between (FSR+ 2) and (FSR+λη), and the other part of the data is modulated into the optical signals of wavelengths λ2 and λη, and sent to the coupler. The AWG1 multiplexes the received downstream optical signals of the wavelengths λ1~λη that carry the data into an optical signal, which is also sent to the coupler.

Step 205: The coupler sends the received mixed optical signal to the AWG3 through the circulator. The circulator transmits the optical signal from the coupler to the AWG3 at the far end node on the one hand and the optical signal from the AWG3 to the AWG2 on the other hand. Step 206: AWG3 demultiplexes the received mixed optical signal, sends an optical signal with a wavelength of λΐ to ONU1, and transmits an optical signal with a wavelength of λ2 to ONU2, ..., and the light with a wavelength of λη The signal is sent to ONUn, and the optical signals of wavelengths (FSR+ 2) and (FSR+λη) from the tunable laser are sent to ONU2 and ONUn, respectively.

Step 207: ONU2 and ONUn respectively receive optical signals carrying data from Rx1 and Rx2, and other ONUx receive optical signals carrying data from Rx1.

When multiple nodes exceed the transmission capacity of the first channel at the same time, the transceiver controller of the OLT will control the tunable laser to share the load for these nodes. In general, the OLT's transceiver controller determines which node to load the load first, and which nodes share the load according to the two dimensions of emergency and overload. For nodes that need to share the load urgently, the OLT's transceiver controller will serve it first, and then serve other nodes. In this embodiment, the OLT transceiver controller controls the tunable laser to serve the ONU2 node first, and then serves the OUNn node. Similarly, the OLT transceiver controller controls the tunable laser to serve the ONUn node first, and then the OUN2. Node service, which is handled according to the specific conditions of the two nodes. This situation occurs when multiple residential nodes exceed the transmission capacity of their first channel at the same time, for example, during busy hours during the night. The method described in this embodiment can also achieve dynamic bandwidth adjustment. The embodiments of the present invention can not only provide dynamic adjustment of bandwidth, but also implement optical access network fault protection. As shown in Figure 10, when one of the transmitters Txl~Txn, such as Τχn, fails, the OLT's transceiver controller will receive an alarm for the transmitter failure. After the transmitter and receiver of the OLT receives the transmitter failure alarm, there are two solutions for fault protection according to the adjustable range of the tunable laser.

Example 3

When the wavelength of the tunable laser is adjustable between 1~(FSR+ n), Barrier protection requires the cooperation between the OLT and the ONUn. The specific steps for implementing fault protection on the OLT and ONUn are as follows: See Figure 10 and Figure 11:

1. On the OLT side:

Step 301: The transceiver controller of the OLT receives the fault alarm of the transmitter Txn, and will close Τχη„

Step 302: The transceiver controller of the OLT checks whether the tunable laser has a spare transmission capability. If yes, step 303 is performed; otherwise, step 307 is performed.

Step 303: In the time slot of the tunable laser having the wavelength λη, the transceiver controller of the OLT sends a transmitter switching request message to the ONUn, and starts a timer with a time Toutl.

Step 306: The OLT transceiver controller checks whether the transmitter switching confirmation message sent by the ONUn is received in the Toutl time. If the transmitter switching confirmation message is received, the process proceeds to step 305. Otherwise, step 306 is performed.

Step 305: The transceiver controller of the OLT terminates the timer, and in the time slot of the tunable laser with the wavelength λη, the downlink data sent to the ONUn is modulated into the optical signal with the wavelength λη, and the optical signal is sent to the ONUn.

Step 306: ONUn has abandoned the fault protection, terminates the fault protection attempt, sends an alarm, and ends.

Step 307: The transceiver controller of the OLT checks whether the tunable laser can release part of the transmission capability. If yes, step 303 is performed; otherwise, step 308 is performed.

Step 308: The tunable laser is occupied, failing to protect, sending an alarm, and ending.

2. On the ONUn side:

Step 401: The ONUn transceiver control module receives an alarm that the downlink signal is lost, and starts a timer with a time of Tout2.

Step 402: During the Tout2 time, the ONUn transceiver control module checks whether it is from Rxl. A transmitter switch request message is received, and if yes, step 403 is performed, otherwise step 404 is performed.

Step 403: The transceiver control module of the ONUn sends a transmitter switching confirmation message to the transceiver controller of the OLT, and restarts receiving downlink data at the Rx1.

Step 404: The transceiver control module of the OLT does not support fault protection, gives up the attempt, and sends an alarm.

In order to ensure that the fault protection is implemented, the time value Toutl of the timer is far greater than Tout2, and the transmitter switch confirmation message can be received within the Toutl time. Example 4

When the wavelength of the tunable laser is adjustable between (FSR + λ Ι ) ~ (FSR + n), in order to achieve fault protection, the OLT end and the ONUn end need to cooperate. The specific steps for implementing fault protection on the OLT and ONUn are as follows: See Figure 10 and Figure 12:

1. On the OLT side:

Step 501: The transceiver controller of the OLT receives the fault alarm of the transmitter Txn, and will close Τχη„

Step 502: The transceiver controller of the OLT checks whether the tunable laser has a spare transmission capability. If yes, step 503 is performed; otherwise, step 507 is performed.

Step 503: In the time slot of the tunable laser having the wavelength of (FSR+λη), the OLT's transceiver controller sends a channel switch request message to ONUn, and starts a timer of time Toutl.

Step 504: The OLT transceiver controller checks whether the channel switch confirmation message sent by the ONUn is received in the Toutl time. If the channel switch confirmation message is received, the process proceeds to step 505. Otherwise, step 506 is performed.

Step 505: The transceiver of the OLT terminates the timer, and the wavelength of the tunable laser is In the time slot of (FSR+λη), the downlink data transmitted to ONUn is modulated into an optical signal of wavelength (FSR+λη), and the optical signal is transmitted to ONUn.

Step 506: ONUn does not support fault protection or has abandoned fault protection, terminates the fault protection attempt, sends an alarm, and ends.

Step 507: The transceiver controller of the OLT checks whether the tunable laser can release part of the transmission capability. If yes, step 503 is performed; otherwise, step 508 is performed.

Step 508: The tunable laser is occupied, failing to protect, sending an alarm, and ending.

2. On the ONUn side:

Step 601: The ONUn transceiver control module receives the downlink signal loss alarm, enables the Rx2 receiver, and starts a timer of time Tout2.

Step 602: During the Tout2 time, the ONUn transceiver control module checks whether a channel switch request message is received from Rx2. If yes, step 603 is performed; otherwise, step 604 is performed.

Step 603: The ONUn transceiver control module sends a channel switch confirmation message to the transceiver controller of the OLT, and restarts receiving downlink data at Rx2.

Step 604: The OLT transceiver controller does not support fault protection, abandoning the attempt, and sending the channel switching message and the channel switching confirmation message are the key to ensure that the fault protection is realized. Therefore, it is necessary to properly set the Tout1 and the Tout2. Generally, the time value Toutl of the timer is greater than Tout2, and the channel switching acknowledgement packet can be received in the time of the Toutl. The specific value needs to be set according to the network. Referring to FIG. 13, an embodiment of the present invention provides a device for dynamically adjusting bandwidth and fault protection of an optical access network, where the device includes a traffic detection module, a downlink service information distribution module, and a fault. Protection management message processing module;

The traffic detection module is configured to detect whether the downlink service information sent to the ONUx exceeds the transmission capability of the fixed bandwidth downlink channel of the ONUx. If the traffic detection module sends the traffic distribution detection command and the downlink service information to the downlink service information distribution module, the traffic detection module sends the traffic control module. The module sends the downlink service information to the downlink service information offloading module;

The fault protection management packet processing module is configured to process the received failover packet, and send a shunt control instruction to the downlink service information offloading module.

The downlink service information offloading module is configured to receive the offloading control command and the downlink service information sent by the traffic detection module and the fault protection management packet processing module, and then distribute the downlink service information and then send the downlink service information.

The device further includes a fixed bandwidth downlink channel transmission control module, and the fixed bandwidth downlink channel transmission control module includes a control unit and a sending unit;

The control unit is configured to control the wavelength of the optical signal of the corresponding laser emitter according to the different receiving objects of the service information;

The transmitting unit is configured to modulate the traffic information into the optical signal emitted by the laser transmitter and send it out.

The device further includes a dynamic bandwidth downlink channel transmission control module, and the dynamic bandwidth downlink channel transmission control module includes a control unit and a sending unit;

The control unit is configured to control the wavelength of the optical signal of the tunable laser according to the difference of the transmission priority of the service information;

The transmitting unit is configured to modulate the service information into the optical signal emitted by the tunable laser and transmit it. Referring to FIG. 14, an embodiment of the present invention further provides an optical access network device, where the device includes a fixed bandwidth downlink channel receiving module, a dynamic bandwidth downlink channel receiving module, and an uplink service sending. Send module

The fixed bandwidth downlink channel receiving module is configured to receive the service information from the fixed bandwidth downlink channel;

The dynamic bandwidth downlink channel receiving module is configured to receive downlink service information from the dynamic bandwidth downlink channel when the fixed bandwidth downlink channel fails or the downlink service information exceeds the transmission capability of the fixed bandwidth downlink channel;

The uplink service sending module is configured to send uplink service information.

The device simultaneously receives downlink service information from the fixed bandwidth downlink channel and/or the dynamic bandwidth downlink channel. The embodiments described above are only preferred embodiments of the present invention, and the usual changes and substitutions made by those skilled in the art within the scope of the present invention are included in the scope of the present invention.

Claims

Claim

A method for dynamically adjusting the bandwidth of an optical access network, characterized in that a fixed bandwidth downlink channel and a dynamic bandwidth downlink channel are established between each optical path terminal ONU and the optical network unit OLT, and the following steps are performed:

2. The method of claim 1 wherein

The establishing a fixed bandwidth downlink channel between each ONU and the OLT includes: setting a specific fixed wavelength λ laser transmitter for each ONU in the OLT, and setting a corresponding one for receiving the specific fixed in each ONU a first fixed wavelength λ laser receiver of a signal of a wavelength laser transmitter, wherein a fixed wavelength corresponding to each fixed bandwidth downstream channel is different;

The establishing a dynamic bandwidth downlink channel between the ONU and the OLT includes:

A tunable wavelength laser emitter having a wavelength range of (n*FSR+l)~(n*FSR+n) is set in the OLT, and a second fixed wavelength laser receiver having a corresponding wavelength of FSR+λζ· is set in each ONU. The FSR is a free spectral range of a wavelength routing module of the OLT, where n is an integer greater than or equal to zero, and the tunable wavelength laser transmitter is wavelength-adjusted, and the second fixed-wavelength laser receiver of the ONU is time-sharing. Communication.

The method according to claim 1, wherein before the OLT enables the dynamic bandwidth downlink channel, the method further includes:

The OLT sends a management packet to the ONU to notify the ONU to receive downlink service information on the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel at the same time.

The method for dynamically adjusting the bandwidth of the optical access network according to claim 1, wherein after the step of enabling the dynamic bandwidth downlink channel, the method further includes:

When the OLT detects that the downlink service information sent to the ONU does not exceed the transmission capacity of the ONU's fixed bandwidth downlink channel, the OLT closes the dynamic bandwidth downlink channel of the ONU, and sends a control packet to notify the ONU.

The method for dynamically adjusting the bandwidth of the optical access network according to claim 1, wherein the OLT sends the downlink service information sent to the ONU to the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel to Before the ONU, the method further includes:

The OLT offloads the downlink service information sent to the ONU to the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel according to the load balancing algorithm.

The method for dynamically adjusting the bandwidth of the optical access network according to any one of the preceding claims, wherein the fixed bandwidth downlink channel provides an exclusive fixed bandwidth for each ONU; The ONUs provide shared dynamic bandwidth scheduled on demand.

The method for dynamically adjusting the bandwidth of an optical access network according to any one of claims 1 to 5, wherein if the OLT detects that the downlink service information sent to more than one ONU exceeds the fixed bandwidth of the ONU The transmission capability of the downlink channel further includes:

The OLT determines the sequence of the ONUs occupying the shared dynamic bandwidth according to the service emergency and the overload of the ONU;

The OLT sends the downlink service information that is sent to the ONU to the ONU through the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel. The OLT sends the downlink service information to the shared dynamic bandwidth according to the sequence. Each of the ONUs.

The method for dynamically adjusting the bandwidth of an optical access network according to any one of claims 1 to 5, wherein the OLT is connected to n ONUs, and the fixed bandwidth downlink channel of the OLT and the first ONU is used by the OLT. a fixed-wavelength laser emitter 波长 having a wavelength of λ and a fixed-wavelength laser receiver Rx having a wavelength of λ of the i-th ONU; The channel is composed of a tunable wavelength laser transmitter having a wavelength range of FSR+λΙ to FSR+λη covering the wavelength routing module of the wavelength routing module and a fixed wavelength laser receiver having a wavelength of FSR+λζ· on the i-th ONU; The FSR is a free spectrum range of the wavelength routing module; the OLT sends the downlink service information that is sent to the ONU to the ONU through the fixed bandwidth downlink channel and the dynamic bandwidth downlink channel, including:

The OLT divides the downlink service information to be sent to the ONU into two parts, and part of it is modulated into an optical signal of wavelength λ, which is sent to the fixed wavelength laser receiver of the ONU with a wavelength of λ by a fixed wavelength laser transmitter of wavelength λ; Modulating to an optical signal having a wavelength of FSR+, adjusting a wavelength of the tunable wavelength laser emitter to FSR+, and transmitting the portion of the optical signal to the ONU at a fixed wavelength laser having a wavelength of FSR+λ by the tunable wavelength laser emitter On the receiver.

The method for dynamically adjusting the bandwidth of the optical access network according to any one of claims 1 to 5, wherein when the fixed bandwidth downlink channel for transmitting downlink service information fails, the method further includes the following steps:

The OLT enables the dynamic bandwidth downlink channel;

The OLT transmits the downlink service information sent to the ONU through the dynamic bandwidth downlink channel.

The method for dynamically adjusting bandwidth of an optical access network according to claim 9, wherein the OLT comprises a fixed wavelength laser transmitter Tx having a wavelength and a wavelength range covering FSR+λΙ to FSR+λη. a wavelength-modulated laser transmitter, the ONU comprising a fixed-wavelength laser receiver Rxl of wavelength λ and a fixed-wavelength laser receiver Rx2 of wavelength FSR+λζ';

The fixed bandwidth downlink channel for transmitting the downlink service information is faulty: the fixed wavelength laser transmitter Tx with the wavelength of the OLT is λί;

The OLT sends downlink service information sent to the ONU through the dynamic bandwidth. The line channel is sent as:

The OLT modulates the downlink service information sent to the ONU into an optical signal having a wavelength of FSR+λ, and transmits the optical signal through the tunable wavelength laser transmitter.

11. The method of dynamically adjusting bandwidth of an optical access network according to claim 9, wherein the OLT comprises a fixed wavelength laser emitter Tx having a wavelength and a tunable wavelength covering a range of λΐ to FSR+λη. a laser transmitter, the ONU includes a fixed-wavelength laser receiver Rx1 having a wavelength of λ; i is greater than or equal to 1 and less than or equal to n, and the fixed-bandwidth downlink channel for transmitting downlink service information is faulty: the wavelength of the OLT is λί The fixed wavelength laser transmitter Tx fails;

The OLT sends the downlink service information sent to the ONU through the dynamic bandwidth downlink channel as:

The OLT modulates the downlink service information sent to the ONU into an optical signal of wavelength λ, and transmits the optical signal through the tunable wavelength laser transmitter.

12. An optical line terminal OLT, wherein the optical line terminal comprises a transceiver controller, n fixed-wavelength laser emitters respectively corresponding to n ONUs connected to the OLT, and a tunable wavelength laser emitter The transceiver controller includes a traffic detection module, a downlink service information distribution module, a dynamic bandwidth downlink channel transmission control module, and a fixed bandwidth downlink channel transmission control module;

The traffic detection module is configured to detect whether the downlink service information to be sent to the ONU exceeds the transmission capability of the fixed bandwidth downlink channel of the ONU, and if yes, the traffic detection module sends the traffic distribution control command and the downlink service information to the The downlink service information offloading module; otherwise, the downlink service information is sent to the downlink service information offloading module; the downlink service information offloading module is configured to: when receiving the offloading control instruction sent by the traffic detecting module, according to The downlink service letter sent by the traffic detection module The downlink service information to be sent to the ONU is offloaded, and the part sent through the fixed bandwidth downlink channel and the part sent through the dynamic bandwidth downlink channel are obtained; or, when not received from the traffic detection module. When the flow control command is used, the downlink service information from the traffic detection module is used as a part sent through the fixed bandwidth downlink channel;

The fixed bandwidth downlink channel sending control module is configured to modulate, by the downlink service information offloading module, a part of the fixed bandwidth downlink channel to be an optical signal of a fixed wavelength laser transmitter wavelength corresponding to the ONU, and send the optical signal ;

The fixed wavelength laser transmitter is configured to generate a corresponding fixed wavelength laser; the dynamic bandwidth downlink channel transmission control module is configured to adjust a wavelength of the adjustable wavelength laser transmitter, and send the downlink service information shunt module And partially transmitting the optical signal transmitted by the dynamic bandwidth downlink channel to the wavelength of the tunable wavelength laser transmitter and transmitting the optical signal;

The optical line terminal according to claim 12, wherein the dynamic bandwidth downlink channel transmission control module comprises a control unit and a sending unit;

The control unit is configured to control an optical signal wavelength of the adjustable wavelength laser emitter to be an integer multiple of a wavelength difference FSR of a fixed wavelength laser emitter corresponding to the ONU;

The sending unit is configured to modulate part of the service information sent by the downlink service information offloading module through the dynamic bandwidth downlink channel to the optical signal transmitted by the tunable wavelength laser transmitter, and send the signal.

The optical line terminal according to claim 12, wherein the optical line terminal further comprises a fault protection management message processing module;

The fault protection management packet processing module is configured to switch the packet according to the received fault. Sending a shunt control instruction to the downlink service information offloading module;

The downlink service information offloading module is configured to use the downlink control information from the fault protection management packet processing module as the part that is sent through the dynamic bandwidth downlink channel.

15. An optical network unit ONU, characterized in that the ONU comprises a first fixed wavelength laser receiver Rxl of wavelength λί and a second fixed wavelength laser receiver Rx2 of wavelength FSR+λζ, wherein the Rxl The method is configured to receive downlink service information from a downlink channel with a wavelength of λ, and the Rx2 is configured to receive downlink service information from a downlink channel with a wavelength of FSR+λζ·.

16. An optical access network system, comprising: a transceiver controller, at least one fixed wavelength laser transmitter and a tunable wavelength laser transmitter, and at least one fixed bandwidth downstream channel receiving module and at least one dynamic bandwidth Downstream channel receiving module;

The downlink service information offloading module is configured to offload downlink service information to be sent to the fixed bandwidth downlink channel receiving module according to the traffic distribution control command and the downlink service information sent by the traffic detection module, to obtain a downlink channel through the fixed bandwidth. The part sent and the part sent through the dynamic bandwidth downlink channel;

The fixed bandwidth downlink channel transmission control module is configured to modulate the portion transmitted through the fixed bandwidth downlink channel into an optical signal of the fixed wavelength laser transmitter wavelength;

The fixed wavelength laser emitter is configured to generate a corresponding fixed wavelength laser; the dynamic bandwidth downlink channel transmission control module is configured to adjust the adjustable wavelength laser a wavelength of the transmitter, and modulating the portion transmitted through the dynamic bandwidth downlink channel to an optical signal of the wavelength of the tunable wavelength laser emitter;