CN104768086A - Method and device for mutual communication between optical network units - Google Patents

Abstract

The invention discloses a device and a method for mutual communication between optical network units in an optical line terminal in a PON (Passive Optical Network) of a communication network. The device comprises a 1*2 optical switch and an n*n optical switch. The 1*2 optical switch is provided with an input end, a first output end and a second output end for switching optical signals of uplink data and optical signals of data communication between the optical network units. The n*n optical switch is provided with n*n input ends and n*n output ends, the n*n input ends are used for receiving optical signals of the second output end of the 1*2 optical switch of an optical line terminal from each source PON respectively,and the n*n output ends are used for respectively sending the combined optical signals to an optical loopback device located on the optical line terminal in each source PON or target PON for mainly switching data of the optical network units in the source PON to optical network units in the target PON. In the condition of not increasing external fibers and transmitters of the optical network units, mutual communication between the optical network units crossing the PON can be flexibly realized.

Description

Method and device for mutual communication between optical network units

technical field

The present invention relates to a passive optical network in a communication network, and more particularly relates to a method and a device for mutual communication between optical network units in a passive optical network.

Background technique

Coordinated Multipoint (Co-ordinate MultiPoint: CoMP) technology, as an important application of LTE, has been extensively discussed in LTE. Since it allows different eNBs to cooperate to manage interference and/or participate in joint transmission and reception, CoMP technology can effectively improve the throughput of LTE-A users. However, the CoMP technology needs to exchange user data and/or cell information through the mobile backhaul network, so the performance improvement of CoMP depends largely on the capabilities of the mobile backhaul network. In the CoMP transmission technology, inter-cell information and/or data exchange is performed between adjacent base stations. The logical interface between two base stations, that is, the X2 interface in 3GPP, is used for the exchange of information and/or data between cells.

According to some current research reports, CoMP technology generally requires no more than a few milliseconds of delay and a data capacity of several Gbps. Therefore, low latency and high bandwidth become a bottleneck in the realization of CoMP technology, because they cannot fully meet the data and/or information exchange requirements of CoMP technology. In addition, more frequent handoffs between cellular networks in the future will also require larger, faster information exchange and higher throughput of interfaces between base stations.

Given its huge bandwidth advantage and wide deployment, Passive Optical Network (PON) access technology has been regarded as the most promising solution to ensure cost-effective mobile backhaul for coordinated multipoint transmission technology. In particular, the all-optical intercommunication technology between Optical Network Units (ONUs) can realize direct communication between Optical Network Units without complicated Optical-Electrical-Optical (OEO) conversion and other electrical signal processing , which is a very attractive solution that supports less than 1ms delay and greater than 1Gb/s rate bandwidth in cooperative multipoint transmission technology.

Regarding the communication between all-optical ONUs, the current research results mainly focus on the mutual communication between ONUs in the source PON. However, in practice, ONUs communicating with each other usually belong to different PONs, and remote nodes in these PONs may be in different locations. In this case, it is very important to realize all-optical communication between optical network units between different PONs as shown in FIG. 1 . As shown in Figure 1, the solid line connection is the mutual communication between the optical network units in the source PON, that is, the mutual communication between the optical network units between PON-i and PON-i; the dotted line connection is the inter-PON optical network unit Mutual communication, that is, mutual communication between optical network units between PON-i and PON-j.

In order to optimize all-optical communication between ONUs across PONs when the remote nodes are in different locations, the following technical challenges must be considered:

1) In order to realize the communication between the optical network units, no additional optical fiber can be deployed between the remote node and the optical network unit;

2) In order to reduce the cost of the optical network unit, it is not possible to deploy additional data transmitters that communicate with each other between the optical network units;

3) The optical line terminal can control the mutual communication between optical network units;

4) The remote node architecture of each TDM-PON system should remain unchanged;

5) At the same time, it can support mutual communication between optical network units in the same PON.

Contents of the invention

Based on the above understanding of the background technology and existing technical problems, it would be very beneficial if a device and method for communication between optical network units in an optical line terminal of a passive optical network can be provided.

According to a first aspect of the present invention, an optical line terminal in a PON of a communication network is provided, the communication network includes n PONs, and the optical line terminal includes: a 1×2 optical switch having an input port and The first and second output terminals are used to switch the optical signal of uplink data and the optical signal of data communication between optical network units, the optical line terminal controls the switching of the 1x2 optical switch based on the type of uplink communication, and the uplink The type of communication includes uplink data communication and data communication between optical network units; and an n×n optical switch has n input terminals and n output terminals, and the optical line terminal controls the n based on the type of communication between optical network units. Switching of ×n optical switches, the type of communication between optical network units includes inter-communication between optical network units across PONs or inter-communication between optical network units in the source PON, where n represents the number of PONs in the communication network number, the source PON is the PON that provides the optical signal for the data communication between the optical network units to the input end of the n×n optical switch, and the inter-communication between the optical network units across the PON is from The communication from the source PON to the target PON, where the target PON is any one of the n PONs in the communication network except the source PON.

According to an embodiment of the present invention, the input end of the 1×2 optical switch is used to receive the uplink optical signal from an optical looper, and the optical looper is used to receive the upstream optical signal from a wavelength division multiplexer. uplink optical signal, and forward the uplink optical signal to the 1×2 optical switch, and also used to receive the optical signal from the n×n optical switch and send the optical signal to the wavelength division multiplexer Downlink optical signal for data communication between optical network units.

According to an embodiment of the present invention, the optical line terminal judges that the type of the uplink communication is the uplink During data communication, the optical line terminal controls the 1x2 optical switch to switch to its first output end, and the optical signal of the uplink data is received by the uplink signal receiver; When the request for the uplink data communication of the network unit or the data communication between the optical network units determines that the type of the uplink communication is data communication between the optical network units, the optical line terminal controls the 1×2 The optical switch is switched to the second output end thereof, and the optical signal of the data communication between the optical network units is output to the input end of the n×n optical switch.

According to an embodiment of the present invention, the n input terminals of the n×n optical switch are respectively used to receive the second The optical signals at the output terminals, the n output terminals are used to send the optical signals of the data communication between the optical network units from the corresponding source PON to each corresponding source PON or target PON respectively Optical Line Terminals in .

According to an embodiment of the present invention, the n×n optical switch includes: n 1×n optical switches, wherein each 1×n optical switch has 1 input terminal and n output terminals, and the input terminals are used for receiving an optical signal from the second output port of the 1×2 optical switch of the optical line terminal in the corresponding source PON; each of the n output ports corresponds to the Any one of the n PONs, for switching the optical signal from the second output end of the 1×2 optical switch of the optical line terminal in the corresponding source PON to the source PON or the target The input terminal of the optical combiner of PON; And n optical combiners, wherein each optical combiner has n input terminals and 1 output terminal, and each input terminal in the n input terminals is used to receive signals from for the optical signal at the output end of each of the 1×n optical switches, the optical combiner combines the optical signals from the output ends of each of the 1×n optical switches and outputs the combined optical signal to The optical line termination of the source PON or the target PON.

According to an embodiment of the present invention, when the optical line terminal determines that the type of communication between the optical network units is inter-communication between optical network units in the source PON, the optical line terminal controls the n×n optical The switch is switched to the i_i output terminal of the n output terminals, the former i of the i_i output terminals indicates that the optical signal of the data communication between the optical network units comes from the source PON with the index i, and the latter i The optical signal indicating the data communication between the optical network units is switched to the source PON with the index i; the optical network terminal determines that the type of communication between the optical network units is the cross-PON inter-optical network unit When communicating with each other, the optical line terminal controls the n×n optical switch to switch to the i_j output end of the n output ends, and i in the i_j output end indicates that the optical signal of the data communication between the optical network units comes from For the source PON with the index i, j indicates that the optical signal of the data communication between the optical network units is switched to the target PON with the index j, where j is not equal to i, and i and j are any natural numbers less than or equal to n .

According to an embodiment of the present invention, a downlink signal transmitter is also included, which is used to provide the modulated downlink data optical signal on the downlink wavelength to the wavelength division multiplexer.

According to an embodiment of the present invention, it further includes the uplink signal receiver, which is used to receive the optical signal of the uplink data from the first output end of the 1×2 optical switch and detect the uplink data optical signal to obtain the uplink data.

According to an embodiment of the present invention, it further includes the wavelength division multiplexer, which is coupled to the downlink signal transmitter and the optical loopback device, and is used to combine the modulated downlink data optical signal with different The modulated optical signal for data communication between the optical network units on the communication wavelength is multiplexed into the downlink optical signal, and sent to the optical network unit through a remote node; used to receive data from the optical network unit The uplink optical signal passing through the remote node, wherein the uplink optical signal includes a modulated optical signal of the uplink data combined in a time-division manner and an optical signal of data communication between the optical network units.

According to a second aspect of the present invention, a method for intercommunication between optical network units in an optical line terminal of a PON in a communication network is provided, the communication network includes n PONs, which includes: receiving The optical network unit's request for uplink data communication or data communication between optical network units, the optical signal of uplink data and the optical signal of data communication between optical network units; according to the received uplink data communication or the optical network A request for data communication between units, judging the type of uplink communication and controlling the switching of a 1x2 optical switch, switching the optical signal of the uplink data or the optical signal of data communication between the optical network units according to the type of the uplink communication To the first output end of the 1x2 optical switch or the second output end of the 1x2 optical switch; and judging the type of communication between optical network units and controlling the switching of n×n optical switches, according to the communication between optical network units The optical signal of the data communication between the optical network units from the corresponding source PON is respectively sent to the optical line terminal in each of the corresponding source PON or target PON, and the source PON is to the said The input end of the n×n optical switch provides the PON of the optical signal for data communication between the optical network units, and the target PON is any one of the n PONs in the communication network except the source PON .

According to an embodiment of the present invention, when the optical line terminal determines that the type of the uplink communication is the uplink data communication, the optical line terminal controls the 1x2 optical switch to switch to its first output end, and the uplink The optical signal of the data is received by the uplink signal receiver; when the optical line terminal judges that the type of the uplink communication is data communication between the optical network units, the optical line terminal controls the 1x2 optical switch to switch to its first Two output ports, the optical signal of the data communication between the optical network units is output to the input port of the n×n optical switch.

According to an embodiment of the present invention, when the optical line terminal determines that the type of communication between the optical network units is mutual communication between the optical network units of the source PON, the optical line terminal controls the n×n optical switch switch to the i_i output terminal among the n output terminals, the former i of the i_i output terminals indicates that the optical signal of the data communication between the optical network units comes from the source PON with the index i, and the latter i indicates that the optical signal of the data communication between the optical network units is switched to the source PON with index i; the optical network terminal determines that the type of communication between the optical network units is the optical network unit across PONs When communicating with each other, the optical line terminal controls the n×n optical switch to switch to the i_j output end of the n output ends, and i in the i_j output end indicates the optical signal of the data communication between the optical network units From the source PON with index i, j indicates that the optical signal of the data communication between the optical network units is switched to the target PON with index j, where j is not equal to i, and i and j are any less than or equal to A natural number of n.

According to the content disclosed in the present invention, a method and device for mutual communication between optical network units are proposed. The unique advantages of the present invention are: 1) realize mutual communication between optical network units across PON, and support source Communication between optical network units in PON; 2) Compared with traditional methods, due to the use of all-optical technology between optical network units, it provides extremely low delay and higher-capacity bandwidth, compared with traditional methods, while reducing Complex photoelectric-optical conversion processing of optical line terminals, thereby improving network efficiency and energy saving and environmental protection; 3) No additional transmitters are required between optical network units, thereby greatly reducing the cost of optical network units and the complexity of wavelength management; 4) No It is necessary to deploy additional optical fibers between the optical network unit and the remote node, and it is fully compatible with the optical distribution network (Optical Distribution Network: ODN) of the current TDM-PON system; 5) The optical line terminal can control the mutual communication between the optical network units communication, so there is great flexibility in practical implementation.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

FIG. 1 shows a schematic diagram of mutual communication between optical network units;

FIG. 2 shows a schematic diagram of an optical network unit architecture;

Fig. 3 shows a schematic diagram of an optical line terminal framework for mutual communication between all-optical optical network units across a PON;

FIG. 4 shows a schematic diagram of an n×n optical switch;

Figure 5 shows a schematic diagram of a 2×2 optical switch; and

Fig. 6 shows a flowchart of mutual communication between optical network units.

In the drawings, the same or similar reference numerals denote the same or similar means (modules) or steps throughout different views.

Detailed ways

In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings show, by way of example, specific embodiments in which the invention can be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Accordingly, the following detailed description is not limiting, and the scope of the invention is defined by the appended claims. It should be noted that although the steps of the relevant methods in the present invention are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in this specific order, or that all shown operations must be performed to achieve the desired result. As a result, instead, the steps described herein can be performed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and/or one step may be decomposed into multiple steps for execution.

FIG. 1 shows a schematic diagram of mutual communication between optical network units, and the description of this figure has been given in the background art, so it will not be repeated here.

In order to better describe the solution of the present invention, firstly, the structure of the optical network unit 200 is explained. Fig. 2 shows the schematic diagram of optical network unit framework, and it comprises wavelength division multiplexer (Wave Division Multiplexing: WDM) 203, optical loopback device 202, the data receiver 205 between optical network unit, downlink receiver 201 and uplink data and OUN between data transmitters 204 . The ONU 200 can simultaneously transmit uplink data and data between ONUs.

The wavelength division multiplexer 203 is coupled to the downlink receiver 201 and the optical loopback 202, and is used to separate the optical signal of a certain downlink wavelength from the optical signal of a second communication wavelength.

The optical loopback device 202 is used to receive the optical signal from the data transmitter between the uplink data and the optical network unit, and send it to the wavelength division multiplexer 203; for receiving the optical signal from the wavelength division multiplexer 203 Optical signals for data communication between units and looped back to data receivers between optical network units.

The inter-ONU data receiver 204 is used for receiving the optical signal of the inter-ONU data communication from the optical loopback 202 and receiving the inter-ONU data therein.

The downlink receiver 201 is used for receiving downlink data in the downlink optical signal with a certain downlink wavelength from the wavelength division multiplexer 203 . Wherein, the downlink wavelength is different from the second communication wavelength.

The data transmitter 205 between the uplink data and the optical network unit is used to combine the uplink data and the data between the optical network units in a time-division multiplexing manner, convert the electrical signal of the combined data into an optical signal, and combine the uplink data with the optical network Data between units is modulated onto the same upstream wavelength and sent to the optical loopback 202 .

As shown in Fig. 2, the uplink data and the data between the ONUs are time-division multiplexed and modulated to the transmitter of the same uplink wavelength. The data is input to the wavelength division multiplexer through the optical loopback device. The data between the optical network units is looped back to the data receiver between the optical network units of the source PON or target PON through the optical line terminal, and the uplink data is sent to the receiver in the optical line terminal through the wavelength division multiplexer 203 .

For example, in one ONU 200, uplink data is transmitted in time slot T _i ; data between ONUs is transmitted in time slot T _i +t. It can be seen from Fig. 2 that because the uplink data and the data between the ONUs use the same transmitter, the cost of the ONUs can be effectively reduced. In addition, the dynamic bandwidth allocation protocol can also coordinate uplink data and data communication between optical network units.

Since the uplink data and the data between the ONUs share the same wavelength, it is inevitable that part of the bandwidth of the uplink data will be occupied by the data between the ONUs. In order to improve the performance of uplink data communication, uplink data packets are first buffered in the optical network unit buffer area. Once there is redundant bandwidth, the dynamic bandwidth allocation protocol will compensate for the loss of uplink data bandwidth, that is, when data transmission between optical network units When the bandwidth requirement is low, more time slots are allocated to the uplink data transmission of the ONU.

In order to overcome the problems of the conventional solutions as described in the background art, the present invention proposes a solution as shown in FIG. 3 . FIG. 3 shows a schematic diagram of an optical line terminal architecture for inter-communication between all-optical optical network units across a PON. The optical line terminal 300 in this figure includes a downlink signal transmitter 305 , a wavelength division multiplexer 303 , an uplink signal receiver 302 , an optical loopback 301 , a 1×2 optical switch 304 and an n×n optical switch 306 .

The downlink signal transmitter 305 is used to provide the modulated downlink data optical signal on a certain downlink wavelength to the wavelength division multiplexer 303 .

The wavelength division multiplexer 303 is coupled to the downlink signal transmitter 305 and the optical loopback 301, and is used for data communication between the modulated downlink data optical signal and the modulated optical network unit on different communication wavelengths The optical signal is multiplexed into a downlink optical signal, which is sent to the ONU via the remote node 307; and is also used to receive an uplink optical signal from the ONU via the remote node 307. Wherein, the uplink optical signal includes a modulated optical signal of uplink data combined in a time-division manner and an optical signal of data communication between optical network units.

The uplink signal receiver 302 is used for receiving the uplink data optical signal from the first output end of the 1×2 optical switch 304 and detecting the uplink data optical signal to obtain the uplink data.

The optical loopback 301 is used to receive the uplink optical signal from the wavelength division multiplexer 303, and forward the uplink optical signal to the 1×2 optical switch 304, and is also used to receive the light from the n×n optical switch 306 The signal is used to send the downlink optical signal of the data communication between the optical network units to the wavelength division multiplexer 303 .

The 1×2 optical switch 304 has an input terminal and first and second output terminals, which are used to switch the optical signal of uplink data and the optical signal of data communication between optical network units, and the optical line terminal 300 controls the 1×2 switch based on the type of uplink communication. When the optical switch 304 is switched, the type of uplink communication includes uplink data communication and data communication between optical network units. When the optical line terminal 300 judges that the type of uplink communication is uplink data communication based on the request for uplink data communication from the optical network unit or the data communication between the optical network units, the optical line terminal 300 controls the 1x2 optical switch 304 to switch to the first An output terminal, the optical signal of the uplink data is received by the uplink signal receiver 302; the optical line terminal 300 judges that the type of uplink communication is an optical network unit based on the request of the uplink data communication from the optical network unit or the data communication between the optical network units During data communication between optical network units, the optical line terminal 300 controls the 1×2 optical switch 304 to switch to the second output end, and the optical signal of data between optical network units is output to the input end of the n×n optical switch 306 . The input end of the 1×2 optical switch 304 is used to receive the uplink optical signal from the optical loopback 301 .

The n×n optical switch 306 is used to realize inter-communication between optical network units across PONs, and also supports inter-communication between optical network units in the source PON. The n×n optical switch 306 has n input terminals and n output terminals. The optical line terminal 300 controls the switching of the n×n optical switch 306 based on the type of inter-ONU communication, the type of inter-ONU communication includes inter-ONU inter-communication across PONs or inter-ONU inter-communication in a source PON , where n represents the number of PONs in the communication network, the source PON is the PON that provides the optical signal for data communication between the optical network units to the input end of the n×n optical switch, and the mutual communication between the optical network units across the PON is In the communication from the source PON to the target PON, the target PON is any one of the n PONs in the communication network except the source PON.

The n input terminals of the n×n optical switch 306 are respectively used to receive optical signals from the second output terminals of the 1×2 optical switch 304 of the optical line terminal in the corresponding source PON, and the n output terminals are used for The optical signals from the data communication between the optical network units of the corresponding source PON are respectively sent to the optical loopback unit 301 in the OLT in each corresponding source PON or target PON. The n×n optical switch 306 can be located in the optical line terminal of any one of the n PONs, and is used to switch the data of one optical network unit of the source PON to another optical network unit of the source PON or to switch the data of the optical network unit of the source PON The data is switched to the optical network unit of the target PON. Although the various remote nodes 307 shown in FIG. 3 are in different locations, the remote nodes 307 may also be in the same location.

FIG. 4 shows a schematic diagram of an n×n optical switch 306 . As shown in FIG. 4, the n×n optical switch 306 is composed of n 1×n optical switches and n optical combiners. Each 1×n optical switch in the n 1×n optical switches has 1 input terminal and n output terminals, and its input terminal is used to receive the 1×2 optical switch from the optical line terminal in the corresponding source PON The optical signal at the second output end of the n output end; each of the n output ends corresponds to any one of the n PONs, and is used to switch the 1×2 optical switch from the optical line terminal in the corresponding source PON The optical signal at the second output end of the switch is switched to the input end of the optical combiner of the source PON or the target PON.

Each optical combiner in the n optical combiners has n input terminals and 1 output terminal, and each input terminal in the n input terminals is used to receive signals from each of the n×n optical switches 306, respectively. The optical signal at the output end of the 1×n optical switch, the optical combiner combines the optical signal from the output end of each 1×n optical switch and outputs the combined optical signal to the optical ring in the optical line terminal in the source PON or target PON return device. Each target PON corresponds to an optical combiner.

The optical line terminal located in each PON can control the 1×n optical switches corresponding to the optical line terminal. Normally, the n×n optical switch 306 is switched to a state of performing communication between optical network units in the source PON. When there is a communication request between optical network units of other PONs except the source PON, the 1×n optical switches of the corresponding n×n optical switches are switched to perform mutual communication between optical network units across PONs. The state of the communication. In this case, data between ONUs across PONs may be routed to ONUs of corresponding target PONs.

In order to better illustrate the communication mechanism between optical network units, a communication scenario between optical network units between two different PONs can be assumed. In this scenario, as mentioned above, in order to achieve cross-PON or source PON The optical network units communicate with each other. As shown in FIG. 5 , the 2×2 optical switch is composed of two 1×2 optical switches and two optical combiners. Each PON corresponds to an optical combiner. The input ports of the optical combiner of PON-1 are 1-1 port and 2-1 port. For example, the 1-1 port indicates that data from the ONU of PON-1 is routed back to PON-1, and the 2-1 port indicates that data from the ONU of PON-2 is routed to PON -1. The optical combiner corresponding to PON-1 combines the optical signals of port 1-1 and port 2-1 and outputs them to PON-1. The optical line terminal located on PON-1 or PON-2 can independently control the 1×2 optical switch corresponding to PON-1 or PON-2.

Fig. 6 shows a flowchart of communication between optical network units. When an optical network unit wants to establish communication with another optical network unit, in the allocated time slot T _i +t, the data between the optical network units is modulated at the upstream wavelength and transmitted to the PON to which the optical network unit belongs Optical line terminal.

In step S100, the OLT receives a request for uplink data communication or inter-ONU data communication from an ONU, an optical signal for uplink data and an optical signal for data communication between ONUs.

In step S200, the optical line terminal judges the type of uplink communication and controls the switching of the 1x2 optical switch according to the received request for the uplink data communication or the data communication between the ONUs, and according to the type of uplink communication Switching the optical signal of uplink data or the optical signal of data communication between the ONUs to the first output end of the 1x2 optical switch or the second output end of the 1x2 optical switch.

If the type of uplink communication is uplink data, the optical line terminal controls the 1x2 optical switch to switch the uplink data optical signal to the first output terminal, and the uplink data optical signal is received by the receiver.

If the type of uplink communication is data communication between optical network units, the optical line terminal controls the 1x2 optical switch to switch the optical signal of data communication between optical network units to the second output end, and the optical signal of data communication between optical network units is output to the input end of an n×n optical switch.

In step S300, the optical line terminal judges the type of communication between optical network units and controls the switching of the n×n optical switch, and according to the type of communication between optical network units, the optical network unit of the data from the corresponding source PON The signal is sent to the optical line termination in each corresponding source PON or target PON respectively.

When the optical line terminal determines that the type of communication between the optical network units is the mutual communication between the optical network units of the source PON, the optical line terminal controls the n×n optical switch to switch to the i_i output port among the n output ports, where The previous i in the i_i output terminal indicates that the optical signal of the data communication between the optical network units comes from the source PON with the index i, and the latter i indicates that the optical signal of the data communication between the optical network units is switched to the index i of the source PON. As shown in FIG. 5( a ), the PON-1 optical line terminal switches the 1×2 optical switch corresponding to the source PON-1 among the 2×2 optical switches to the 1-1 port. The output signal of the 1-1 port is routed back to the source PON-1 via an optical loopback in the source PON-1.

When the optical network terminal determines that the type of communication between optical network units is inter-communication between optical network units across the PON, the optical line terminal controls the n×n optical switch to switch to the i_j output end of the n output ends, and i_j output end of the i_j output end The optical signal indicating the data communication between the optical network units comes from the source PON with index i, j indicates that the optical signal for data communication between the optical network units is switched to the target PON with index j, where j is not equal to i, i and j is any natural number less than or equal to n. As shown in FIG. 5( b ), the source PON-1 optical line terminal switches the 1×2 optical switch corresponding to the source PON-1 among the 2×2 optical switches to the 1-2 port. The output signal of the 1-2 port is routed to the target PON-2 through the optical loopback device in the target PON-2, so as to realize mutual communication between optical network units across PONs.

Those skilled in the art should understand that the optical line terminals in other PONs can also control the n×n optical switches to switch to other ports in the same manner.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all respects as exemplary and not restrictive. Furthermore, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. A plurality of elements recited in device claims may also be embodied by one element. The words first, second, etc. are used to denote names and do not imply any particular order.

Claims (12)

1. An optical line terminal in a PON of a communication network, said communication network comprising n PONs, said optical line terminal comprising: 1×2 optical switch, having an input terminal and first and second output terminals, which are used to switch the optical signal of uplink data and the optical signal of data communication between optical network units, and the optical line terminal is controlled based on the type of uplink communication The switching of the 1x2 optical switch, the type of the uplink communication includes uplink data communication and data communication between optical network units; and An n×n optical switch having n input terminals and n output terminals, the optical line terminal controls switching of the n×n optical switch based on the type of communication between optical network units, the type of communication between optical network units Including inter-communication between optical network units across PONs or inter-communication between optical network units in a source PON, where n represents the number of PONs in the communication network, and the source PON is an optical switch to the n×n The input end of the PON provides the optical signal for the data communication between the optical network units, the inter-communication between the optical network units across the PON is communication from the source PON to the target PON, and the target PON is the Any one of the n PONs in the communication network except the source PON. 2. The optical line terminal according to claim 1, wherein the input end of the 1×2 optical switch is used to receive an uplink optical signal from an optical looper, and the optical looper is used to receive The uplink optical signal from the wavelength division multiplexer, and forward the uplink optical signal to the 1×2 optical switch, also used to receive the optical signal from the n×n optical switch and used to send the optical signal to the The wavelength division multiplexer sends the downlink optical signal of the data communication between the optical network units. 3. The optical line terminal according to claim 1, characterized in that, the optical line terminal judges the uplink data communication based on the request from the optical network unit or the data communication between the optical network units. When the type of the uplink communication is the uplink data communication, the optical line terminal controls the 1x2 optical switch to switch to the first output end, and the optical signal of the uplink data is received by the uplink signal receiver; When the optical line terminal determines that the type of the uplink communication is data communication between the optical network units based on the request from the optical network unit for the uplink data communication or the data communication between the optical network units, the The optical line terminal controls the switching of the 1×2 optical switch to the second output end thereof, and the optical signal of the data communication between the optical network units is output to the input end of the n×n optical switch. 4. The optical line terminal according to claim 1, wherein the n input terminals of the n×n optical switch are respectively used to receive the 1 from the optical line terminal in the corresponding source PON The optical signals of the second output terminals of the ×2 optical switch, the n output terminals of which are used to send the optical signals of the data communication between the optical network units from the corresponding source PON to each An optical line terminal in the corresponding source PON or target PON. 5. The optical line terminal according to claim 1, wherein the n×n optical switch comprises: n 1×n optical switches, wherein each 1×n optical switch has 1 input terminal and n output terminals, and the input terminal is used to receive the signal from the optical line terminal in the corresponding source PON The optical signal of the second output terminal of the 1×2 optical switch; each output terminal of the n output terminals corresponds to any one of the n PONs, and is used to transmit the optical signal from the corresponding switching the optical signal at the second output of the 1×2 optical switch of the optical line terminal in the source PON to the input of an optical combiner of the source PON or the target PON; and n optical combiners, wherein each optical combiner has n input terminals and 1 output terminal, and each input terminal in the n input terminals is used to respectively receive signals from each of the 1×n optical switches The optical signal at the output end of the optical combiner combines the optical signal from the output end of each of the 1×n optical switches and outputs the combined optical signal to the source PON or the target PON The optical line terminal. 6. The optical line terminal according to claim 1, wherein when the optical line terminal judges that the type of communication between the optical network units is mutual communication between optical network units in the source PON, the optical line terminal The line terminal controls the n×n optical switch to switch to the i_i output end of the n output ends, and the previous i in the i_i output end indicates that the optical signal of the data communication between the optical network units comes from the index The source PON is i, and the latter i indicates that the optical signal of the data communication between the optical network units is switched to the source PON with the index i; the optical network terminal determines the communication between the optical network units The type is that when the inter-PON optical network units communicate with each other, the optical line terminal controls the n×n optical switch to switch to the i_j output end of the n output ends, and the i_j output end of the i_j output end The optical signal indicating the data communication between the optical network units comes from the source PON with the index i, and j indicates that the optical signal for the data communication between the optical network units is switched to the target PON with the index j, where j Not equal to i, i and j are any natural numbers less than or equal to n. 7. The optical line terminal according to claim 1, further comprising a downlink signal transmitter, which is used to provide the modulated downlink data optical signal on the downlink wavelength to the wavelength division multiplexer. 8. The optical line terminal according to claim 1, further comprising the uplink signal receiver, which is used to receive the uplink data from the first output port of the 1×2 optical switch and detecting the optical signal of the uplink data to obtain the uplink data. 9. The optical line terminal according to claim 1, further comprising the wavelength division multiplexer, which is coupled to the downlink signal transmitter and the optical loopback device, and is used to transmit the via The modulated downlink data optical signal and the modulated optical signal for data communication between the optical network units on different communication wavelengths are multiplexed into the downlink optical signal, and sent to the optical network unit through a remote node; receiving the uplink optical signal passing through the remote node from the optical network unit, wherein the uplink optical signal includes a modulated optical signal of the uplink data combined in a time-division manner and the optical network Optical signal for data communication between units. 10. A method for mutual communication between optical network units in an optical line terminal of a PON in a communication network, the communication network comprising n PONs, comprising: receiving a request from the optical network unit for uplink data communication or data communication between optical network units, and an optical signal for uplink data and an optical signal for data communication between optical network units; According to the received request for the uplink data communication or the data communication between the optical network units, determine the type of the uplink communication and control the switching of the 1x2 optical switch, and transmit the optical signal of the uplink data according to the type of the uplink communication Or the optical signal of the data communication between the optical network units is switched to the first output end of the 1x2 optical switch or the second output end of the 1x2 optical switch; and judging the type of communication between the optical network units and controlling the switching of n×n optical switches, and sending the optical signals of the data communication between the optical network units from the corresponding source PON according to the type of communication between the optical network units to an optical line terminal in each of said corresponding source PON or target PON, said source PON being a PON that provides an optical signal for data communication between said optical network units to an input end of said n×n optical switch, The target PON is any one of the n PONs in the communication network except the source PON. 11. The method according to claim 10, wherein when the optical line terminal judges that the type of the uplink communication is the uplink data communication, the optical line terminal controls the 1x2 optical switch to switch to its second an output terminal, the optical signal of the uplink data is received by the uplink signal receiver; when the optical line terminal judges that the type of the uplink communication is data communication between the optical network units, the optical line terminal controls the The 1x2 optical switch is switched to its second output end, and the optical signal of the data communication between the optical network units is output to the input end of the nxn optical switch. 12. The method according to claim 10, wherein when the optical line terminal determines that the type of communication between the optical network units is mutual communication between the optical network units of the source PON, the optical line terminal controls The n×n optical switch is switched to the i_i output terminal among the n output terminals, and the previous i in the i_i output terminal indicates that the optical signal of the data communication between the optical network units comes from the The source PON, the latter i indicates that the optical signal of the data communication between the optical network units is switched to the source PON with index i; the optical network terminal determines that the type of communication between the optical network units is the When the inter-PON optical network units communicate with each other, the optical line terminal controls the n×n optical switch to switch to the i_j output end of the n output ends, and i in the i_j output end indicates the optical The optical signal for data communication between network units comes from the source PON with index i, and j indicates that the optical signal for data communication between optical network units is switched to the target PON with index j, where j is not equal to i, i and j are any natural numbers less than or equal to n.