WO2008003215A1

WO2008003215A1 - A method, system and device for realizing broadcast in wdm-pon

Info

Publication number: WO2008003215A1
Application number: PCT/CN2007/001688
Authority: WO
Inventors: Huafeng Lin; Wei Huang; Jun Zhao; Tao Jiang; Feng Wang; Jun Chen; Yuntao Wang; Guo Wei; Xuliang Zhang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-06-26
Filing date: 2007-05-24
Publication date: 2008-01-10
Also published as: CN101068129A; CN101068129B

Abstract

A method, system and device for realizing broadcast in WDM-PON are provided, the said method comprises: the data to be transmitted by broadcasting is modulated into wide spectrum light; the wide spectrum light carrying the data to be transmitted by broadcasting is transmitted to multiplexing and de-multiplexing device; the said multiplexing and de-multiplexing device divides the wide spectrum light carrying the data to be broadcast transmitted; the multiplexing and de-multiplexing device transmits the divided light signal with different wavelengths to optical network units; the said optical network units perform O/E conversion to the received light signal, and demodulate the said data. The invention overcomes the shortage of the prior art, simplifies the WDM-PON, reduces the demand for the handling ability of the OLT, reduces the complexity and cost for networking the WDM-PON, and it can realize broadcast and/or multicast service in WDM-PON.

Description

Method, system and device for realizing broadcast in wavelength division multiplexing passive optical network The application claims to be submitted to the Chinese Patent Office on June 26, 2006, the application number is 200610061355.7, and the invention name is "one realized in WDM-PON" The method of broadcasting and/or multicasting services and the system thereof, the priority of the Chinese patent application, the entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of PON (passive optical network) technology, and in particular, to a method, system and device for implementing broadcast in a wavelength division multiplexing passive optical network. Background technique

At present, as users increase the demand for various broadband services, such as high-quality video information services (such as

VoD (Video on Demand) services, etc., have higher and higher requirements on transmission rate. To meet the bandwidth requirements of users, there must be a data transmission rate of 100 Mbps. The existing dial-up modem, ADSL (Asymmetric Digital Subscriber Loop, non- Access methods such as symmetrical digital line subscriber lines and CM (Cable Modem) are no longer sufficient. Therefore, the demand for fiber-optic access networks is growing rapidly, and passive optical networks can meet these new business requirements. Moreover, it is also economical, convenient for operation and maintenance of the user access network.

As shown in FIG. 1 , a PON usually includes an OLT (opital line terminal) 101, an ODN (optical distribution network) 102, and a plurality of ONUs 103 (optical network units) in a central office. Or ONT (Optical Network Termination). For convenience of explanation, the ONU is used uniformly below. The OLT provides an optical interface with the ODN and provides an interface on the network side to provide a cross-connection capability between the ODN side of the OLT and the network side of the OLT to complete bidirectional service transmission with the ONU. The OLT can coexist with the local switch. The ONU can also be installed at the remote end. The ONU provides an optical interface with the ODN to implement the interface function on the ODN user side, and completes the two-way service transmission with the OLT. It can be placed at the user's location. The ODN provides a transmission path for two-way service delivery between the OLT and the ONU.

WDM-PON is one of the implementation methods of PON. The basic principle of WDM-PON is that different optical wavelength signals form different channels between OLT and ONU. In the downlink direction, these optical signals are multiplexed into one mixed signal and transmitted to the remote end. Node, demultiplexed into individual optical signals at the remote node And transmitting to different ONUs to complete the transmission of downlink data; in the uplink direction, the optical signals from the respective ONUs are multiplexed into a mixed signal on the remote node, and transmitted to the OLT, and the OLT completes the cancellation of the mixed signal. Use and data recovery to complete the transmission of uplink data.

With the complexity and cost of WDM-PON network equipment, a large number of WDM-PON implementation architectures have emerged. However, WDM-PON is logically a peer-to-peer network structure. In the implementation of broadcast (analog or digital TV) and multicast services, WDM-PON is generally used for in-band multi-copy transmission of data. The defects are obvious: When many users order the same program, because the data is copied into many copies and transmitted to different users through different wavelengths, the OLT is required to have strong processing power, which will make the OLT become It is complicated and costs rise.

There are different technical solutions to solve this problem in the prior art, one of which is shown in Figure 2,

AWG{ Arrayed Waveguide Grating, FSR (Free Spectrum Range) feature to efficiently transmit multicast. This scheme first uses n fixed-wavelength lasers 20 to generate lasers having wavelengths of FSR+λΙ to FSR+λη, respectively, and then combines the above-mentioned n lasers into a hybrid unmodulated laser through coupler 21, and then uses an external modulator 22 The multicast data is once modulated into the above-mentioned lasers having wavelengths of FSR+λΙ to FSR+λη, and then the optical amplifier 23 is used to divide the n lasers carrying the multicast data into n parts by a brancher 24, and pass through The combiner 25 mixes the optical signals carrying the downlink unicast data of the respective users into one signal, and inputs them to the respective inputs of the AWG of the NXN of the first stage.

After the wavelength routing of the first-stage AWG and the second-level AWG, each ONU finally receives the optical signal carrying the downlink unicast data of the ONU and the optical signal carrying the multicast data, and the coarse wave division inside the ONU is 26 PD (PhotoDiode) 27 and demodulation module 28, the final ONU 201 will recover the user's unicast data and multicast data, and forward it to the corresponding device for processing.

Although this scheme can well overcome the shortcomings of multi-copy in-band multicast implementation, because of the expensive laser and two-stage AWG used in this scheme, the cost is high and the system is very complicated.

Two solutions of the prior art is a single wavelength transmission data broadcast using a single wavelength _λ Α to transmit digital television signals and analog television broadcast signal is carried on the first telecommunications carrier network WDM-PON, and in O /E (photoelectric conversion), then use the copper shaft of the cable network Cable (cable) to carry, this solution can solve the broadcast problem in WDM-PON, the system is relatively simple, and the cost is relatively low.

However, the transmission of this scheme broadcasts through two networks (telecom data network and cable television network), and these two networks may belong to different operators. This will greatly increase WDM-PON due to conflicts of interest between operators. Difficulties in the implementation of Triple-Play (data, vocabulary and video triple-play).

In addition, according to the established digital home cable broadcasting standard, it is necessary to carry analog and digital broadcast signals at the same time, which requires about 850M of bandwidth. At present, the maximum bandwidth of the cable deployed in the home to carry the broadcast service is about 550M. In one solution, the deployed cable network needs to be modified, which is also the limitation of the application of this solution.

The third solution of the prior art adopts a separate broadcast wavelength for each user, and each ONU receives two wavelengths of optical signals, one carrying unicast data and the other carrying broadcast data, but this scheme is not utilized. The periodic nature of the FSR of the AWG, so the number of AWG ports at the remote node (RN, Remote Node) will be more, and the cost is very high due to the use of a fixed wavelength laser of almost twice the prior art scheme 2 described above. high.

In the prior art, a solution combining the foregoing technical solution 2 and the technical solution 3 is further combined, and the digital broadcast television signal is mixed with the downlink unicast data of the user, and transmitted in the optical signal of the unicast wavelength of the user. The analog broadcast television signal is transmitted in a separate optical signal with a wavelength of λΑ as in the prior art scheme 2 described above, and after photoelectric conversion, is transmitted to each user's home by a cable television network.

This scheme uses the mixed transmission of digital broadcast television signals and the user's downlink unicast data, which increases the system complexity of the OLT. Similarly, the transmission of digital broadcast television also has the problem of in-band multi-copy technology, and the processing capability of the OLT. It will become a bottleneck of the system. In addition, the problems existing in the above prior art solution 2 cannot be solved in this solution.

Summary of the invention

Embodiments of the present invention provide a method and system for implementing broadcast in a wavelength division multiplexing passive optical network, so as to reduce networking complexity when implementing broadcast and/or multicast services in a WDM-PON.

Embodiments of the present invention also provide an optical line terminal to implement broadcast and/or in WDM-PON. Or multicast service.

To this end, the embodiment of the present invention adopts the following technical solutions:

A method for implementing broadcast in a WDM-PON, the method comprising:

Modulating data that needs to be transmitted by broadcasting into broad spectrum light;

Transmitting, to the multiplex demultiplexing device, the wide spectrum light carrying the data required to be broadcastly transmitted; the multiplex demultiplexing device performing spectral line division on the wide spectrum light carrying the data required to be broadcast transmitted;

The multiplexing demultiplexing device transmits the split optical signals of different wavelengths to the optical network unit; the optical network unit performs photoelectric conversion on the received optical signal to demodulate the data. The embodiment of the invention further provides a system for implementing broadcast in a WDM-PON, the system comprising:

An optical line terminal for modulating data to be broadcast in wide spectrum light;

a multiplexing demultiplexer, configured to perform spectral line division on the wide-spectrum light carrying the data to be broadcasted, and transmit the split optical signals of different wavelengths to the optical network unit;

The optical network unit is configured to perform photoelectric conversion on the received optical signal to demodulate the data. The embodiment of the invention further provides an optical line terminal, including:

An uplink processing module, configured to demultiplex each uplink optical signal from the uplink signal, and recover uplink data from each uplink optical signal;

a downlink processing module, configured to demultiplex data of each optical terminal unit from downlink data from a higher-level device, and modulate data of each optical terminal unit into optical signals of different wavelengths;

A broadcast processing module for modulating data that needs to be broadcasted into wide spectrum light.

In the embodiment of the present invention, the FSR periodicity and the spectrum splitting characteristic of the multiplexing demultiplexing device are used to modulate the broadcast and/or multicast data or signals onto the wide spectrum light generated by the broad spectrum light source, and transmit the signal to the multiplexing demultiplexing device. And then dividing the broad spectrum light by using the spectrum splitting characteristic of the multiplexing demultiplexing device, and outputting optical signals of different wavelengths carrying broadcast and/or multicast data or signals respectively at each output end thereof, the technical solution Simplifies the WDM-PON network, reduces the requirements for OLT processing capability, reduces the complexity and cost of WDM-PON networking, and implements broadcast and/or multicast services in WDM-PON simply and cost-effectively. . DRAWINGS

Figure 1 is a network structure diagram of an existing PON system;

The figure shows the system structure diagram of the prior art scheme for transmitting multicast using the FSR characteristics of the AWG; FIG. 3 is a schematic diagram of the FSR periodic principle of the AWG;

Figure 4 is a schematic diagram of AWG line segmentation;

5 is a schematic diagram of a light language of a broad spectrum light source 1 and a broad spectrum light source 2 according to an embodiment of the present invention;

6 is a block diagram of a WDM-PON system for implementing a broadcast service according to an embodiment of the present invention;

FIG. 7 is a flowchart of implementing a broadcast service according to an embodiment of the present invention;

FIG. 8 is a block diagram of a WDM-PON system for implementing a multicast service according to an embodiment of the present invention.

detailed description

When implementing the broadcast in the WDM-PON, the embodiment of the present invention transmits the data or signal that needs to be broadcasted and transmitted to the wide-spectrum light generated by the wide-spectrum light source, and then transmits the data to the multiplexing demultiplexing device, and then uses the multiplexing demultiplexing device. The spectrum splitting feature divides the wide-spectrum light, and outputs optical signals of wavelengths (FSR+λΙ) - (FSR+λη) respectively carrying data or signals that need to be broadcasted and transmitted at respective output ends, optical network unit After receiving, O/E conversion is performed and demodulated.

The details are described below in conjunction with the drawings and specific embodiments.

The multiplex demultiplexing device in the embodiment of the present invention may be an AWG or a WGR (Wavelength Grating Router), and the AWG is taken as an example in the embodiment of the present invention. The AWG has the FSR periodicity characteristic shown in Figure 3. When one optical signal of wavelength λ1~λη is input to the input end of an AWG, the light of the wavelength λΐ is output at the first output end. Signal, the first output outputs an optical signal of wavelength λη; according to the FSR periodicity of the AWG, when the optical signal of wavelength (nxFSR+λΙ) is input to the input end of the AWG, it will also be the first in the AWG. Output on one output. Similarly, the optical signal of (nxFSR+λη) will be output on the first output of the AWG. Therefore, in the embodiment of the present invention, the optical signal of the wavelength λΐ carrying the broadcast signal and the optical signal of the wavelength FSR+λΙ carrying the unicast data are output at the first output end of the AWG, and the wavelength of the broadcast signal is carried. The optical signal of λη and the optical signal of the wavelength FSR+λη carrying the unicast data are output at the nth output of the AWG.

The AWG also has a line segmentation function, as shown in Figure 4, where a represents an AWG in an Ι The input of the wide-spectrum light source, b represents the transmission spectrum of the AWG, then the wide-spectrum light is split by the AWG, and the optical signal with the center wavelength of λ1~λ is output on the N output ends of the AWG. , c and d represent the optical terms output on the first output and the third output, respectively.

The embodiment of the present invention utilizes the FSR periodicity and spectral line segmentation characteristics of the AWG described above, and the light source portion employs two low-cost broad-spectrum light sources, which are referred to as a wide-spectrum light source 1 and a broad-spectrum light source 2, respectively. Among them, the optical maps of the broad spectrum light source 1 and the broad spectrum light source 2 satisfy the requirements shown in Fig. 5, that is, they must be separated by an integral multiple of the FSR.

As shown in FIG. 6, the system of the embodiment of the present invention includes: an OLT 61, an AWG (referred to as a third AWG in the text for convenience of explanation) 62, and a plurality of ONUs 63.

The foregoing OLT 61 mainly includes: a broadcast processing module 611, a downlink processing module 612, an uplink processing module 613, a coupler 614, and a circulator 615.

The broadcast processing module 611 is configured to modulate the data or signal that needs to be broadcasted into the broadband demodulation device, and further includes the wide spectrum light source 2, the optical amplifier 4, and the modulator 3, and the wide spectrum light source. 2 for generating broad-spectrum light, the modulator 3 is for modulating a broadcast signal (analog or digital or a mixture of the two, hereinafter) into a wide-spectrum light, and the optical amplifier 4 is for amplifying the modulated wide-spectrum light Finally, the broad spectrum light carrying the broadcast signal is output to an input of the coupler 614.

The downlink processing module 612 is configured to demultiplex the data of each optical terminal unit from the downlink data from the upper-level device, and modulate the data of each optical terminal unit into the optical signals of different wavelengths, where the method further includes: The processing module 5, the broad spectrum source 1, the optical amplifier 6, the first AWG 7 and the modulator array 8 are exchanged. The uplink processing module 613 further includes: a second AWG 9, a PD array 10, and a demodulator array 11.

When the unicast data is downlink, the switching processing module 5 receives the IP packet data packet from the upper-level device, performs switching forwarding according to the destination address, and outputs downlink unicast data of each user on different ports; the wide-spectrum light source 1 is used for Generating broad-spectrum light, the optical amplifier 6 is used for power amplification of the broad-spectrum light generated by the broad-spectrum light source 1; the first AWG 7 receives the broad-spectrum light from the optical amplifier 6, and performs spectral line division of the broad-spectrum light, and the output wavelengths are respectively The optical signal of λ1~λη is used to modulate the downlink unicast data of each user into the optical signals of the above-mentioned wavelengths λ1~λη respectively; finally, the modulator array 8 carries the downlink order of each user. The optical signals of the broadcast data are output to respective inputs of the coupler 614.

Wherein, the coupler 614 completes the wide-spectrum light carrying the broadcast signal and the downlink carrying the users. The optical signals of the unicast data are combined into one mixed light, and the mixed light is output to the input terminal of the circulator 615.

The circulator 615 outputs the mixed light from the coupler 614 in the downward direction to the third AWG 62, and outputs the mixed light from the third AWG 62 in the upstream direction to the second AWG 9 of the upstream processing module 613.

The uplink processing module 613 is configured to demultiplex the uplink optical signals from the uplink signal and recover the uplink data from the respective uplink optical signals, and further includes a second AWG 9, a PD array 10, and a demodulator array 11. The second AWG 9 is configured to receive the mixed light in the uplink direction from the circulator 615, and route the optical signals of different wavelengths of the uplink unicast data of each user in the mixed light to different output ends respectively; For performing photoelectric conversion on optical signals of different wavelengths; the demodulator array 11 is configured to perform demodulation on the electrical signals carrying the uplink unicast data of each user, and restore the uplink data.

The functions of the third AWG 62 in the uplink direction and the downlink direction are different, and are respectively described below: Downstream direction: After receiving the mixed light in the downlink direction from the circulator 615 of the OLT 61, the wide spectrum light carrying the broadcast signal is completed. The line segmentation performs optical routing on the wavelengths of the λ1~λη optical signals carrying the downlink unicast data of each user respectively; the result of the spectral line division is that the wavelengths carrying the broadcast signals are respectively outputted at the respective output ends of the third AWG 62. The optical signals are respectively (FSR+l)~(FSR+?oi); and the result of the optical routing is that the wavelengths of the downlink unicast data carrying the users respectively output at the respective outputs of the third AWG 62 are λ1~λ light, respectively. Signals; finally, at each output end of the third AWG 62, two optical signals respectively carrying the downlink unicast data and the broadcast signal are output, and the wavelength interval is FSR; finally, the third AWG 62 respectively outputs the optical signals on the respective outputs. Transfer to the corresponding individual ONUs 63;

In the uplink direction, the third AWG 62 receives, from each ONU 63, the wavelengths of the uplink unicast data carrying the users, respectively, the λ1~λη optical signals, and then combines the optical signals of the wavelengths λ1~λη into a mixed light in the upward direction. And transmitted to the circulator 615 of the OLT 61 described above.

As shown in FIG. 6 , taking the ηth ONU 63 as an example, the ONU mainly includes three parts: a coarse wavelength division 631, a Ο/Ε and a demodulation module 632, and a receiving and loopback modulation module 633, where:

The coarse wavelength division 631 is configured to separate the optical signal having the wavelength (FSR+λη) optical signal carrying the broadcast signal and the wavelength λη carrying the downlink unicast data of the ONU user, and output respectively To the O/E and demodulation module 632, the receive and loopback modulation module 633, on the other hand, the upstream light carrying the user's uplink unicast data from the receive and loopback modulation module 633 is transmitted to the third AWG 62.

The O/E and demodulation module 632 receives the optical signal having the wavelength (FSR + λη) carrying the broadcast signal, completes the photoelectric conversion and demodulation, and recovers the broadcast signal.

Downstream direction: The receiving and loopback modulation module 633 performs the photoelectric conversion and demodulation function of the optical signal of the wavelength λη carrying the downlink unicast data of the ONU user, recovers the downlink unicast data of the user, and sends the downlink unicast data to the next level. Equipment processing.

Upstream direction: The receive and loopback modulation module 633 receives the user's uplink unicast data from the next level device and passes the RSOA (reflective semiconductor optical amplifier) or the injection lock FP LD (Fabriel-Perot (FP) - LD) laser) generates uplink light for carrying uplink unicast data, and modulates the user's uplink unicast data into the uplink light, and finally outputs the uplink light carrying the user's uplink unicast data to the coarse wavelength divider. 631.

The flow of the method for implementing broadcast in a WDM-PON according to the embodiment of the present invention is as shown in FIG. 7, and includes the following steps:

Step 701: Modulate data that needs to be broadcasted into the wide spectrum light; the data may be broadcast service data or multicast service data;

Step 702: Transmit the broad spectrum optical that carries the data to the multiplexing demultiplexing device.

Step 703: The multiplexing demultiplexing device performs spectral line segmentation on the broad spectrum light carrying the data. When the multiplexing demultiplexing device performs spectral line segmentation on the wide spectrum light carrying the data, the Wide-spectrum light is split into optical signals having wavelengths of (FSR+ 1) and (FSR+A2) (FSR+λη);

Step 704: Transmit the split optical signals of different wavelengths to the optical network unit.

The multiplexing demultiplexing device may output optical signals of respective wavelengths to different optical network units through different output ends of the multiplexing demultiplexing device;

Step 705: The optical network unit performs photoelectric conversion on the received optical signal to demodulate the data. The system architecture shown in FIG. 6 is taken as an example to specifically describe the transmission process of the broadcast signal and the downlink data in the embodiment of the present invention, and the transmission process when the unicast data is uplinked.

The transmission process of the downlink broadcast signal includes:

1. The broad spectrum light source 2 produces broad spectrum light, and the modulator 3 modulates the broadcast signal into the broad spectrum light and The optical amplifier 4 is amplified and input to an input end of the coupler 614; the wide-spectrum light source 1 generates a wide-spectrum light (an integer multiple of the FSR from the wide-spectrum light source 2), and the generated broad-spectrum light is amplified by the optical amplifier 6 and input to the first AWG 7 The line division is performed, and the optical signals of wavelengths λ1 to λη are respectively output after the line division, and the modulator array 8 modulates the downlink unicast data of each user into the optical signals of the above-mentioned wavelengths λ1 to λη, respectively, and sends them into the coupling. Each input of the 614;

2. The coupler 614 combines the broad spectrum light carrying the broadcast signal with the optical signal carrying the downlink unicast data of each user into a mixed light, and outputs the mixed light to the input end of the circulator 615;

3. The circulator 615 outputs the mixed light from the coupler 614 in the downward direction to the third AWG 62;

4. The third AWG 62 performs the splitting of the wide-spectrum light carrying the broadcast signal, and outputs the optical signals carrying the broadcast signals respectively (FSR+λΙ)~(FSR+λη) on the respective output ends thereof; The third AWG pair 62 carries the downlink unicast data of each user, and the wavelengths of the λ1~λη optical signals respectively complete the optical routing, and the wavelengths of the downlink unicast data carrying the users respectively output on the respective output ends are respectively λ1~ Λη optical signal; finally, at each output end of the third AWG 62, two optical signals respectively carrying the downlink unicast data and the broadcast signal are output, and the wavelength interval is FSR; the third AWG 62 respectively transmits the optical signals on the respective output ends To the corresponding individual ONU63;

5. The coarse wavelength division 631 in the ONU 63 separates the optical signals carrying the broadcast signal optical signals and the downlink unicast data carrying the ONU users, and outputs them to the Ο/Ε and demodulation module 632, respectively, and the receive and loopback modulation. Module 633;

6. After receiving the optical signal carrying the broadcast signal, the Ο/Ε and demodulation module 632 in the ONU 63 completes the photoelectric conversion and demodulation to recover the broadcast signal; the receiving and loopback modulation module 633 carries the ONU user. The optical signal of the downlink unicast data is photoelectrically converted and demodulated, and the downlink unicast data of the user is restored and sent to the next-level device for processing.

In addition, the transmission process when the unicast data is uplinked includes:

1. The receiving and loopback modulation module 633 of the ONU 63 receives the uplink unicast of the user from the next-level device, and then modulates the uplink unicast data of the user into the uplink optical, and finally outputs the uplink optical light carrying the uplink unicast data of the user. To the coarse wavelength divider 631; 2. The coarse wavelength division 631 transmits the uplink optical carrying the uplink unicast data to the third AWG 62, and the third AWG 62 receives, from each ONU, the wavelengths of the uplink unicast data carrying the users, respectively, λ1~λη optical signals, and then Combining the wavelengths of λ1~λη optical signals into a mixed light in the upward direction, and transmitting to the circulator 615 of the OLT 61;

3. The second AWG 9 of the OLT 61 receives the mixed light in the uplink direction from the circulator 615, and routes the optical signals of different wavelengths carrying the uplink unicast data of each user in the mixed light to different output ends respectively; The optical signals of different wavelengths are photoelectrically converted and input to the demodulator array 11. The demodulator array performs demodulation on the electrical signals carrying the uplink unicast data of each user, and restores the uplink unicast data.

Since the transmission of broadcast signals and the transmission of unicast data are done in different channels, and these two services are likely to be provided by different service (content) providers, there are four combinations of these two service rights: That is, the permissions of the two services are not available, there are two kinds of business rights, only the rights of the broadcast signal, only the rights of the data service. Therefore, in addition to the normal access control of the data service, the WDM-PON system in the embodiment of the present invention can also control the reception of the broadcast signal by the following methods, including the following steps:

The network administrator configures the privilege module according to the device ID of the ONU, and the privilege module is configured to store the rights of the ONU to receive broadcast or multicast, for example, including: device ID of the ONU, multicast receiving permission, and broadcast receiving permission;

During the registration authentication process after the ONU is powered on, the ONU sends a request message for receiving the broadcast to the OLT;

After receiving the request message for receiving the broadcast message from the ONU, the OLT extracts the device ID of the ONU in the request message, and performs the function verification by using the index to the permission module configured by the network administrator, and transmitting the corresponding result according to the right P艮 verification result. Broadcast control messages (prohibited or allowed) to the corresponding ONU;

After receiving the broadcast control message, the ONU performs corresponding action according to the content of the control message. If the ONU allows reception, the optical receiving and demodulating circuit of the broadcast signal is activated to receive the broadcast signal. Otherwise, the light receiving and decoding of the broadcast signal is turned off. Adjust the circuit.

The above WDM-PON system for transmitting broadcast service signals can also be used to transmit multicast service data, thereby solving the problem of using the in-band multi-copy technology to transmit multicast. As shown in Figure 8, and Figure 6 The system shown differs in that the OLT 81 includes a multicast processing module 811, a downlink processing module 612, an upstream processing module 613, a coupler 614, and a circulator 615. The multicast processing module 811 has the same structure as the broadcast processing module 611, and includes: a wide spectrum light source 2, a modulator 3, and an optical amplifier 4. The difference between the transmission of the multicast signal by the system and the transmission of the broadcast signal by the system shown in FIG. 6 is that, in this embodiment, the exchange processing module 5 increases the extraction of the multicast data from the downlink data packet in addition to the exchange and forwarding of the downlink data. The function of the switching processing module 5 extracts the multicast data from the downlink data packet, sends it to the modulator 3 of the multicast processing module 811 for modulation, and the modulator 3 modulates the multicast data to the wide spectrum generated by the broad spectrum light source 2. In the light, the subsequent processing method is similar to the transmission broadcast, and will not be described again.

In this embodiment, the OLT can also capture the request from the ONU to join the multicast group, and complete the multicast proxy function on the one hand, and determine the ONU according to the authentication result returned by the upper-layer multicast server on the other hand. Whether the OLT has permission to request the multicast group data, and sends a multicast service control packet to the ONU according to the judgment result, and the ONU filters out the multicast group that the OLT allows to receive according to the multicast service control packet from the OLT. Data, but directly discard multicast group data that is not allowed by the OLT. After the ONU decrypts the multicast group data allowed by the OLT, it will send it to the corresponding next-level device for further processing.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A method for implementing broadcast in a wavelength division multiplexed passive optical network, the method comprising:

The multiplexing demultiplexing device transmits the split optical signals of different wavelengths to the optical network unit; the optical network unit performs photoelectric conversion on the received optical signal to demodulate the data.

2. The method according to claim 1, wherein before the transmitting the broad spectrum light carrying the data to be broadcast transmitted, the method further comprises:

The broad spectrum light carrying the data that needs to be broadcast transmitted is amplified.

The method according to claim 1, wherein the step of the multiplexing demultiplexing device performing line segmentation on the wide spectrum light carrying the data to be broadcast transmitted includes:

The wide-spectrum light carrying the data to be broadcast-transferred is divided into optical signals having wavelengths of (FSR + 1) and (FSR + 2) (FSR + λη), respectively.

The method according to claim 3, wherein the step of the multiplexing demultiplexing device transmitting the split optical signals of different wavelengths to the optical network unit comprises:

Optical signals of respective wavelengths are output to the optical network unit through different outputs of the multiplexing demultiplexing device.

The method according to claim 1, wherein the data that needs to be broadcasted includes multicast service data and/or broadcast service data, and when the multicast service data is transmitted, the method further includes: The downlink service data of the upper-level device extracts the multicast service data that needs to be broadcasted.

The method according to claim 1, wherein the method further comprises: pre-configuring the optical network unit to receive the permission of the data to be broadcasted; and receiving, by the optical line unit, the optical network unit Having the right to send a control message to the optical network unit;

The optical network unit receives the data according to the received information in the control message.

7. A system for implementing broadcast in a wavelength division multiplexed passive optical network, the system comprising:

An optical line terminal for modulating data that needs to be broadcast transmitted in wide spectrum light;

a multiplexing demultiplexer, configured to perform a line segmentation on the wide-spectrum light carrying the data that needs to be broadcasted, and transmit the split optical signals of different wavelengths to the optical network unit;

The optical network unit is configured to perform photoelectric conversion on the received optical signal to demodulate the data.

8. The system according to claim 7, wherein the optical line terminal comprises: a broadcast processing module, configured to generate the wide spectrum light, and modulate the data required to be broadcast transmitted to the wide spectrum The light is transmitted to the multiplex demultiplexer.

9. The system according to claim 7, wherein the multiplexing demultiplexing device is an arrayed waveguide grating or a waveguide grating router.

10. An optical line terminal, comprising:

a downlink processing module, configured to demultiplex data of each optical terminal unit from downlink data from the upper-level device, and modulate data of each optical terminal unit into optical signals of different wavelengths;

The optical line terminal further includes:

And a broadcast processing module, configured to modulate the data that needs to be broadcasted into the wide spectrum light and transmit the data to the multiplexing demultiplexing device.

The optical line terminal according to claim 10, wherein the broadcast processing module comprises:

a broad spectrum light source for generating broad spectrum light carrying the data required for broadcast transmission;

And a modulator, configured to modulate the data required to be broadcast transmitted into the wide spectrum light.

The optical line terminal according to claim 10, wherein the downlink processing module comprises:

The switching processing module is configured to perform the exchange and forwarding of the downlink data, and extract the multicast service data from the downlink data packet received by the downlink processing module when the multicast service is implemented; and transmit the multicast service data to the Modulator.