CN101442377B - Passive optical network system and transmission method and equipment thereof - Google Patents
Passive optical network system and transmission method and equipment thereof Download PDFInfo
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Abstract
The invention discloses a passive optical network (PON) system. A plurality of downlink signals with tight spacing and different wavelength are expanded in the OLT downlink direction through a DWDM expansion technology; a plurality of the downlink signals are coupled to form a path of signals and are transmitted; a wave division de-multiplexing device is added to ODN; a coupling signal is divided into a plurality of downlink signals with different wavelengths; and the downlink signals are input to an ONU, thereby expanding the downlink bandwidth of the PON system. The invention simultaneously discloses a signal transmission method for the passive optical network (PON), an optical line terminal (OLT) and an optical distribution network (ODN). The PON system and the suitable signal transmission method, the OLT and the ODN only need to add a new passive device to the LOT and the ODN, upgrade software and can expand the downlink bandwidth of the network without changing the prior optical fiber network or replacing the prior equipment of a user, thereby saving equipment cost and engineering expense for capacity expansion of the network.
Description
Technical field
The present invention relates to the optical-fiber network technology, particularly a kind of passive optical network and method for transmitting signals thereof, and applicable optical line terminal and the optical distribution of this passive optical network.
Background technology
At present, along with the quickening of " light entering and copper back " paces, optical fiber will be lighted " last kilometer " of network, and the integration of three networks also will begin in Access Network at first.Various EPON (PON) technology, particularly Ethernet passive optical network (EPON) technology based on time division multiplexing (TDM) pattern have begun large-scale application in Access Network at present.
The PON technology is a kind of Optical Fiber Transmission and access technology of point-to-multipoint, formed by optical line terminal (ONU), optical distribution (ODN) and optical network unit (ONU), adopt tree topology, OLT is placed on central office side, ONU is placed on user's side, is connected by ODN between OLT and the ONU.The data transfer mode of PON technology is: descending in the transmission of 1490nm wavelength employing broadcast mode; Up in the transmission of 1310nm wavelength employing time division multiplexing mode.
Day by day universal along with various broadband applications, people are to the demand sustainable growth of access bandwidth.The PON network of having laid in a large number at present will face the upgrade problem of bandwidth expansion very soon.
At present, for the problem in the enterprising uplink bandwidth expansion of optical fiber, the general method that improves speed that adopts.Adopt the method to require to change ustomer premises access equipment, increased the cost of bandwidth expansion and brought larger difficulty to engineering construction.And, technical merit according to present is upgraded to 10Gbps from 1Gbps, only will bring the cost more than 3 times to rise in the optical module part, and acp chip also will adopt in order to support higher rate more expensive technique, and this is just so that the cost of whole equipment will improve 1 times at least.
On the other hand, according to the prediction of mainstream carrier to the Network demand, the main business of pulling bandwidth upgrading is broadcasting or the descending video traffics of multicast type such as Digital Television in the following a very long time.For such demand, the networks in most areas only need to be upgraded or the downlink bandwidth of dilatation network.And adopting the method that improves speed, the bandwidth of network up and down is expanded identical multiple simultaneously.The network bandwidth directly upgrades to 10Gbps from 1Gbps, and bandwidth increases by 10 times, and upstream bandwidth is leading business demand possibly, causes the waste of network investment.Therefore, on 1Gbps speed, it has not been a preferred plan that simple dependence raising speed is come spread bandwidth.
Summary of the invention
In view of this, main purpose of the present invention is to provide a kind of EPON (PON) system, use this passive optical network can be under the condition that does not improve speed the extended network downlink bandwidth, save the cost of the network capacity extension.
The present invention also aims to provide a kind of passive optical network signal transmission method, use the method can be under the condition that does not improve speed the extended network downlink bandwidth, save network capacity extension cost.
Another object of the present invention is to provide the applicable optical line terminal (OLT) of a kind of this EPON and the applicable optical distribution (ODN) of a kind of this EPON, use this OLT and ODN can be under the condition that does not improve speed the extended network downlink bandwidth, save network capacity extension cost.
For achieving the above object, technical scheme of the present invention specifically is achieved in that
The invention discloses a kind of EPON (PON) method for transmitting signals, the method may further comprise the steps:
A, employing dense wave division multipurpose (DWDM) technology are in optical line terminal (OLT) side selected center wavelength, wave-length coverage and wavelength interval, in near selected center's wavelength the selected wave-length coverage, according to selected wavelength interval, export the downstream signal of a plurality of different wave lengths;
B, in the OLT side downstream signal of a plurality of different wave lengths is coupled into one road signal, at down direction transmission coupled signal;
C, optical distribution (ODN) receive coupled signal and with the downstream signal of a plurality of different wave lengths separately;
D, the downstream signal of each wavelength sent respectively to one group of optical network unit (ONU) corresponding to downstream signal of this wavelength.
The method further may further comprise the steps:
A, adopt time division multiplexing (TDM) technology, ONU in time slot separately to OLT report local condition and required upstream bandwidth separately;
B, OLT process and calculate according to local condition and the required upstream bandwidth of ONU report, obtain the allocated bandwidth result, and send it to ONU;
C, ONU send the upward signal of single wavelength to OLT according to the time slot of stipulating among the allocated bandwidth result.
In the light-receiving scope of ONU, and the interior selected center of the technical parameter scope of PON port transmitter and DWDM partial wave demultiplexing device (DWDM Demux) wavelength, wave-length coverage and wavelength interval.
The downstream signal of described different wave length is N, maximum=wave-length coverage of N/wavelength interval.
The invention also discloses a kind of EPON (PON) system, this PON system comprises: optical line terminal (OLT), optical distribution (ODN) and optical network unit (ONU);
OLT, adopt dense wave division multipurpose (DWDM) technology, in OLT side selected center wavelength, wave-length coverage and wavelength interval, in near selected center's wavelength the selected wave-length coverage, according to selected wavelength interval, export the downstream signal of a plurality of different wave lengths, and it is coupled into one road signal, send coupled signal to optical distribution (ODN) downwards;
ODN receives the coupled signal of OLT output, with the downstream signal of a plurality of different wave lengths separately, and the downstream signal of each wavelength is transferred to one group of optical network unit (ONU) corresponding to downstream signal of this wavelength downwards;
The downstream signal of the wavelength that this group ONU of each group ONU reception ODN output is corresponding.
Described ODN further receives the upward signal of the single wavelength that the ONU of time division multiplexing (TDM) sends, and upwards sends it to OLT.
The invention also discloses a kind of optical line terminal (OLT), this OLT comprises: a plurality of descending PON ports and the first dense wave division multipurpose band lead to device (DWDM Band Pass);
Include PON port transmitter in each descending PON port, each PON port transmitter output is different from the downstream signal of the wavelength of other PON port transmitter, send a DWDM Band Pass downwards to, wherein the downstream signal of the different wave length of all PON port transmitter outputs is to adopt dense wave division multipurpose (DWDM) technology to select near centre wavelength in advance in the wave-length coverage, and is determined according to selected wavelength interval;
The one DWDM Band Pass receives the downstream signal of all PON port transmitters, it is coupled into one road signal after, send coupled signal to ODN downwards.
This OLT further comprises 1 two-way PON port;
A described DWDM Band Pass further receives the upward signal of the single wavelength that ODN sends and sends it to two-way PON port;
Two-way PON port comprises PON port transmitter and receiver;
The PON port transmitter of two-way PON port is identical with the PON port transmitter of described descending PON port, and output is different from the downstream signal of the wavelength of other PON port transmitter, and sends a DWDM Band Pass downwards to;
The PON end receiver of two-way PON port receives the upward signal of the single wavelength of DWDM Band Pass transmission.
Comprise in this OLT and all descending PON ports and two-way PON port Multi-point Control Protocol (MPCP) entity one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute;
The MPCP entity that two-way PON port is corresponding is in work (Active) state, receive ONU to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation (DBA) computing engines, calculate the allocated bandwidth result, PON port transmitter by two-way PON port issues the allocated bandwidth result, and it is transmitted to other MPCP entity;
The MPCP entity that each descending PON port is corresponding is in (Standby) for subsequent use state, forbid MPCP agreement and DBA computing engines, receive the allocated bandwidth result that the MPCP entity of two-way PON port calculates, and its PON port transmitter by descending PON port is transmitted downwards.
Comprise in the described OLT and all descending PON ports and two-way PON port MPCP entity one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute;
The MPCP entity that two-way PON port is corresponding is transmitted to all MPCP entities in the PON port set PON-Trunk with up Report frame, the LLID subset (LLID-SubSet) of the pre-configured non-overlapping copies of each MPCP entity, receive ONU in the LLID-SubSet separately to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation DBA computing engines, calculate the allocated bandwidth result, and issue the allocated bandwidth result by the PON port transmitter in the corresponding PON port; A plurality of PON ports form a PON-Trunk;
All MPCP entities share MPCP clock (Mpcp_timer) and next authorizes time started variable (Next_Grant_Start_Time), and upgrade Next_Grant_Start_Time after each run DBA computing engines generates new the mandate;
Mpcp_timer is the MPCP entity of all OLT in the PON-Trunk and the shared MPCP clock of MPCP entity of ONU;
The moment that the initial time Start Time territory of this mandate can be distributed in the next mandate of the Next_Grant_Start_Time indication Grant.
Comprise bridge (Bridge) in the described OLT;
Each port in the bridge is corresponding one by one with all descending PON ports and two-way PON port, automatic media access control (MAC) address learning function of bridge is in illegal state, LLID subset (LLID-Subset) according to this PON port of set configuration of the corresponding ONU that connects of each PON port, each PON port receives the separately interior uplink data frames of LLID-Subset, according to the MAC Address of carrying in the uplink data frames and LLID (LLID), upgrade the separately MAC-LLID mapping table of PON port, MAC-LLID mapping table according to each PON port, MAC Address and bridge port (MAC-PORT) mapping table of configuration bridge, each bridge port issues downlink data according to the MAC-PORT mapping table of bridge, and the control downlink data is from PON port output corresponding to target ONU.
As seen from the above technical solutions, the present invention adopts the DWDM technology to expand the downstream signal of a plurality of different wave lengths at the OLT down direction, it is coupled into one road signal transmits, and in ODN, add partial wave demultiplexing device, coupled signal is separated into the downstream signal input ONU of a plurality of different wave lengths, thereby is not needing to change the downlink bandwidth of having expanded the PON system under the prerequisite of ustomer premises access equipment.Because the present invention only need to add new device or upgrade software to OLT and ODN, and needn't change the existing equipment in the network system, thereby so that up-front investment is all protected, has saved equipment cost and the engineering cost of the network capacity extension.
Description of drawings
Fig. 1 is the composition structure chart of a preferred embodiment of PON of the present invention system.
Fig. 2 is the composition structure chart of middle the first PON-Trunk embodiment illustrated in fig. 1.
Fig. 3 is the composition structure chart of middle the second PON-Trunk embodiment illustrated in fig. 1.
Fig. 4 is the connection diagram of middle bridge embodiment illustrated in fig. 1 and PON port.
Fig. 5 is the flow chart of PON system descending method for transmitting signals of the present invention.
Fig. 6 is the flow chart of PON system uplink method for transmitting signals of the present invention.
Embodiment
For making purpose of the present invention, technical scheme and advantage clearer, referring to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.
The present invention is in descending employing dense wave division multipurpose (DWDM) technology of EPON (PON) system, near former downstream wavelength, expanded closely N wavelength of spacing in the selected wave-length coverage, the pattern that adopts TDM to mix with DWDM, thereby N times of downlink bandwidth being expanded to have the PON system now.
Further, the up direction in the PON system still can use original single upgoing wave progress row transmission, still adopts original TDM pattern, thereby upstream bandwidth is remained unchanged.According to multiple transmission mode of the prior art, for example time division multiplexing, wavelength division multiplexing, CDMA (Code Division Multiple Access) with and mutually combine, also can design at up direction other transmission means.Only be explained as a preferred embodiment to adopt the TDM pattern to carry out uplink by original single wavelength at this.
The DWDM technology can make up one group of optical wavelength and transmit with an optical fiber, in the optical fiber of an appointment, and the fiber carrier of the tight spectrum spacing of multiplexing transmission multichannel.The centre wavelength of DWDM technology take former downstream wavelength as transmission window, near selected a certain wave-length coverage former downstream wavelength, and selected a certain wavelength interval, near should select in the wave-length coverage former downstream wavelength transmits the multi-path light carrier signal of this selected wavelength interval.The adjacent wavelength interval of these optical carriers is very narrow, generally between 0.4nm to 1.6nm.
Fig. 1 is the composition structure chart of a preferred embodiment of PON of the present invention system.In the present embodiment, near descending selecting former downstream wavelength 1490nm expanded N wavelength in the wave-length coverage, and take N=8 as example, up direction still uses original 1310nm wavelength to be example.As shown in Figure 1, PON of the present invention system comprises optical line terminal (OLT) 11, optical distribution (ODN) 12 and optical network unit (ONU) 13.
As shown in Figure 1, OLT11 inside comprises 8 PON ports, and wherein port one 11 to 117 is descending PON port, includes only PON port transmitter, and port one 18 is two-way PON port, comprises PON port transmitter 1181 and PON end receiver 1182.The PON port transmitter of port one 11 to 118 adopts the DWDM technology, wavelength centered by the original downlink working wavelength 1490nm of selected PON system, in near 1490nm the selected wave-length coverage, according to the downstream signal of selected 8 different wave lengths of wavelength interval output, its downstream wavelength is respectively λ
1dTo λ
8dThereby, downlink bandwidth is expanded to 8 times of prior art PON system.The up up wavelength 1310nm that still uses prior art OLT, therefore the operation wavelength λ of the PON end receiver of two-way PON port one 18
0uBe 1310nm, receiving wavelength is the upward signal of 1310nm.Comprise also in the OLT that the first dense wave division multipurpose band leads to device (DWDM Band Pass) 110, one side links to each other with the PON port transmitter of port one 11 to 118 and the PON end receiver of port one 18, opposite side links to each other with the output optical fibre of OLT21, and allowing wavelength at down direction is λ
1dTo λ
8dSignal pass through, receive the downstream signal of all PON port transmitters, the downstream signal of 8 different wave lengths is coupled into one road signal, and this coupled signal exported from OLT21, send ODN22 downwards to by optical fiber, receiving the wavelength that ODN22 transmits at up direction by optical fiber is the upward signal of 1310nm, and upwards sends it PON end receiver of two-way PON port one 18 to.
As shown in Figure 1, comprise among the ODN12 that the second dense wave division multipurpose band leads to device (DWDM Band Pass) 121,123 and 1 Equations of The Second Kind couplers 124 of dense wave division multipurpose partial wave demultiplexing device (DWDM Demux) 122,8 first kind couplers (Coupler).OLT11 links to each other with the 2nd DWDM Band Pass121 by optical fiber.Equations of The Second Kind coupler 124 adopts 1: 8 coupler, only at up direction transfer of data is arranged; 2: 8 the coupler that first kind coupler 123 adopts all has transfer of data at up-downlink direction.8 port side of each first kind coupler 123 connect respectively 8 ONU13.At down direction, one of them port of each first kind coupler 2 port side links to each other with DWDM Demux122 by optical fiber; At up direction, another port of each first kind coupler 2 port side links to each other with a port of Equations of The Second Kind coupler 8 port side, 8 first kind couplers are corresponding continuous respectively with 8 ports of Equations of The Second Kind coupler, and 1 port side of Equations of The Second Kind coupler links to each other with the 2nd DWDM Band Pass121 by optical fiber.The 2nd DWDM Band Pass121 receives the coupled signal that OLT11 exports descending by optical fiber, and sends it to DWDM Demux122; The upward signal of the wavelength 1310nm that transmits at uplink receiving Equations of The Second Kind coupler 124, and it is exported to OLT11 by optical fiber.DWDM Demux122 receives the coupled signal of the 2nd DWDM Band Pass121 output, coupled signal is carried out the partial wave demultiplexing, the downstream signal of 8 different wave lengths separately, then the downstream signal of each wavelength is transferred to a first kind coupler 123 corresponding to downstream signal of this wavelength downwards, sends the one group of ONU13 that is attached thereto downwards to by each first kind coupler 123 again.At up direction, ONU13 adopts the TDM pattern all to send upward signal with the 1310nm wavelength, first kind coupler 123 upwards is transferred to Equations of The Second Kind coupler 124 with the upward signal of ONU23, Equations of The Second Kind coupler 124 receives the upward signal of the 1310nm wavelength of all first kind coupler 123 transmission, by optical fiber it upwards is transferred to the 2nd DWDM Band Pass121.
The ONU13 of each user side is identical, still adopts the wideband receiver of prior art PON system, therefore in the ONU side to λ
1dTo λ
AdThe signal of these 8 wavelength can both correctly receive.8 ONU connect same first kind coupler 123 as one group, receive the light signal of identical wavelength.Still adopt the original time division multiplexing of prior art PON system (TDM) pattern, distinguish the light signal that sends different ONU to different time slots.
In the present embodiment, near 1490nm, adopt DWDM technological expansion 8 wavelength as example in the selected wave-length coverage take descending operation wavelength.The present invention adopts the downstream signal of N different wave length, maximum=wave-length coverage of N/wavelength interval.DWDM technology according to present commercialization, require channel wavelength interval 0.4nm to 1.6nm, and the technical parameter according to receiver wavelength range, different PON port transmitter and the DWDM Demux of the optical receiver of ONU, can select different centre wavelength, wave-length coverage and wavelength interval, then the maximum of N is also with difference.The wave-length coverage that the optical receiver of present ONU can receive is 1480nm to 1500nm, and then wave-length coverage is 1500-1480=20nm.If adopt wavelength interval 1.6nm, then descending extendible wavelength channel number N maximum is about 12.If adopt wavelength interval 0.8nm, then the N maximum is about 25.If adopt wavelength interval 0.4nm, then the N maximum is about 50.For the situation of different N value, need the number of corresponding adjustment PON port and first kind coupler, make it be equal to N, adjust the shunt ratio of Equations of The Second Kind coupler, make it equal 1: N, all the other system configurations are described identical with present embodiment with the realization principle, do not repeat them here.
As the network system of point-to-multipoint delivery, in the PON system, master unit OLT and from adopting Multi-point Control Protocol (MPCP) to realize effective transmission of data between the unit ONU.MPCP can realize a controllable network configuration, such as the allocated bandwidth of the automatic discovery of ONU, point of termination station and inquiry, monitoring etc.In the prior art, operating in the OLT side MPCP corresponding with the PON port is symmetrical work in up-downgoing, namely requires the logical links set of up-downgoing identical, and the upgoing O NU set that the MPCP entity can be managed is consistent with descending ONU set.And in the present invention, the up-downgoing ONU set that requires the MPCP entity to manage is different, and the MPCP entity of the descending PON port one 11 to 117 of OLT side can only transmit at down direction the data of each self-corresponding ONU, does not have data receiver at up direction; The MPCP entity of two-way PON port one 18 can receive the data of all ONU in the descending data that can only transmit the ONU of self correspondence at up direction.So in the present PON system standard, MPCP can not realize the asymmetric mode of operation of up-downlink direction of the present invention.Realize PON of the present invention system, need to do suitable improvement to the MPCP entity of local side.
In OLT, comprise and all descending PON ports and two-way PON port 8 MPCP entities one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute.8 PON ports are formed a PON port set (PON-Trunk).Exist the PON-Trunk of following dual mode can realize the asymmetric mode of operation of up-downlink direction of the present invention.
Fig. 2 is the composition structure chart of the first PON-Trunk, adopts this kind structure only to move a MPCP entity in each PON-Trunk.As shown in Figure 2, the corresponding MPCP entity of each PON port is in each MPCP protocol entity introducing work (Active) and (Standby) for subsequent use two kinds of operating states.By the software configuration, make the MPCP entity 218 of two-way PON port one 18 correspondences be in the Active state, the MPCP entity 211 to 217 of all descending PON port one 11 to 117 correspondences all is in the Standby state.The MPCP entity that is in the Standby state is in the Gate frame of the MPCP entity of Active state in descending forwarding.
For two-way PON port one 18, its corresponding MPCP entity 218 is in the Active state, moves complete MPCP agreement and Dynamic Bandwidth Allocation (DBA) computing engines this moment.When having ONU to transmit upstream data in the system, this ONU sends the Report frame to OLT first, report the local condition of this ONU and required upstream bandwidth to OLT, the MPCP entity of two-way PON port one 18 correspondences is according to the up Report frame of receiving in the OLT, move complete MPCP agreement and DBA computing engines, calculate the allocated bandwidth result, the PON port transmitter by two-way PON port issues this allocated bandwidth result, and it is transmitted to other MPCP entity.The descending Gate frame of the MPCP solid generation of two-way PON port one 18 correspondences, comprise at most 4 mandates (Grant) in the Gate frame, the DBA computing engines is to each ONU fair allocat bandwidth that need to transmit upstream data, and its allocated bandwidth result issues each ONU by the Grant in the Gate frame.After ONU received the Gate frame, the time slot of stipulating according to Grant sent data to OLT.
For descending PON port one 11 to 117, its corresponding MPCP entity 211 to 217 is in the Standby state, forbid moving MPCP agreement and DBA computing engines this moment, receive the allocated bandwidth result that the MPCP entity 218 of two-way PON port one 18 correspondences calculates, and its PON port transmitter by descending PON port one 11 to 117 is transmitted to each self-corresponding ONU downwards.
So so that in each PON-Trunk, only move a MPCP entity, control the uplink signal transmissions of all ONU by this MPCP entity.
Fig. 3 is the composition structure chart of the second PON-Trunk, adopts each the MPCP entity real-time synchronization operation in this kind structure PON-Trunk.As shown in Figure 3, the corresponding MPCP entity 311 to 318 of PON port one 11 to 118 difference.Each MPCP entity is only controlled each self-corresponding ONU, and the Report frame that other ONU is sent does not process.In order to distinguish the range of management of each MPCP entity, prevent conflict, in advance according to the set of the corresponding ONU that connects of the corresponding PON port of each MPCP entity, be the scope of the manageable LLID of each MPCP physical arrangements (LLID) by software, i.e. LLID subset (LLID-SubSet).The MPCP entity that two-way PON port is corresponding is transmitted to MPCP entities all in the PON-Trunk with up Report frame.Each MPCP entity receives ONU in the LLID-SubSet separately to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation DBA computing engines, calculate the allocated bandwidth result, and issue the allocated bandwidth result by the PON port transmitter in the corresponding PON port.The LLID-SubSet non-overlapping copies of configuration, and should be more than or equal to attachable ONU quantity under this PON port.
As shown in Figure 3, each MPCP entity shares two public variables, i.e. MPCP clock (Mpcp_timer) and next mandate time started (Next_Grant_Start_Time) variable.Mpcp_timer is the MPCP clock that the MPCP entity of the MPCP entity of all OLT in the PON-Trunk and ONU shares, all MPCP entity synchronous working in the assurance system.The moment that Next_Grant_Start_Time indicates initial time (Start Time) territory of this mandate in the next Grant to distribute.Each MPCP entity will obtain Next_Grant_Start_Time before processing Report, to guarantee that the Gate that oneself generates can not clash with the Gate that other MPCP entity has generated, after generating new the mandate, each run DBA computing engines all to upgrade this public variable simultaneously, to notify other time slot that MPCP entity has taken oneself.Because the DBA computing engines of each MPCP entity adopts identical algorithm, so the running status of MPCP entity corresponding to each PON port is consistent.Again because adopt the TDM technology, upstream data is that order arrives in time, each Report frame that only has an ONU constantly arrives, and therefore only has a MPCP entity and is processing a Report frame, does not have two MPCP entities and clashes processing the Report frame simultaneously.
The PON system adopts the asymmetric mode of operation of up-downgoing among the present invention, except the operation of MPCP agreement, also needs the data handling procedure of bridge in the OLT (Bridge) is suitably improved.Fig. 4 is the connection diagram of bridge 40 and PON port one 11 to 118 among the OLT11.Each port of bridge 40 is corresponding one by one physically with all descending PON port ones 11 to 117 and two-way PON port one 18 in the OLT.The mode of operation of the standard bridge of prior art PON system is that the data of ONU enter bridge at up direction from certain port of bridge, and then at down direction, the data of going to this ONU will be from this port output of bridge.And among the PON-Trunk of the present invention, at up direction, only have a PON interface can receive the upstream data of all ONU, namely all upstream datas all are port inputs from bridge.According to the mode of operation of prior art standard bridge, downlink data also can only be exported from this port of bridge; And in the present invention, go to the downlink data of different ONU from PON port output corresponding to target ONU, and then require downlink data respectively from 8 PON port outputs, namely downlink data will be exported from 8 ports of bridge respectively.Can export from the corresponding bridge port of target ONU in order to make downlink data, automatic media access control (MAC) address learning function that must forbid bridge, according to the set of the corresponding ONU that connects of each PON port, MAC Address and bridge port (MAC-PORT) mapping table of configuration bridge.At first according to manageable all ONU of the MPCP entity that each PON port is corresponding in the PON-Trunk, dispose the LLID set of this PON port, i.e. LLID subset (LLID-Subset).Each PON port receives the separately interior uplink data frames of LLID-Subset, then according to the MAC Address of carrying in the uplink data frames and LLID (LLID), upgrades the separately MAC-LLID mapping table of PON port.According to the MAC-LLID mapping table of each PON port, dispose the MAC-PORT mapping table of bridge again.As shown in Figure 4, comprise a LLID-Subset in each MPCP entity, be used to refer to manageable all ONU of this MPCP entity.When downlink data output was arranged, each bridge port issued downlink data according to the MAC-PORT mapping table of pre-configured bridge, and the control downlink data is from PON port output corresponding to target ONU.
Use this PON system, in descending employing DWDM pattern, up employing TDM pattern is carried out transfer of data, and the application flow of its transfer of data is as follows:
Fig. 5 is the flow chart of PON system descending method for transmitting signals of the present invention.As shown in Figure 5, PON system descending signal transmission of the present invention may further comprise the steps:
Step 501: adopt the DWDM technology, in OLT side selected center wavelength, wave-length coverage and wavelength interval, near the selected wave-length coverage selected center's wavelength, according to selected wavelength interval, export the downstream signal of a plurality of different wave lengths.Wherein centre wavelength, wave-length coverage and wavelength interval be in the light-receiving scope of ONU, and selected in the technical parameter scope of PON port transmitter and DWDM partial wave demultiplexing device DWDMDemux.
Step 502: in the OLT side, the downstream signal of a plurality of different wave lengths is coupled into one road signal, transmits this coupled signal at down direction.
Step 503:ODN receives this coupled signal and it is carried out the partial wave demultiplexing, with the downstream signal of a plurality of different wave lengths separately.
Step 504: one group of ONU corresponding to downstream signal that the downstream signal of each wavelength is sent respectively to this wavelength.
Fig. 6 is the flow chart of PON system uplink method for transmitting signals of the present invention.As shown in Figure 6, PON system uplink signal transmission of the present invention may further comprise the steps:
Step 601: adopt the TDM technology, the ONU that needs uplink data sending reports local condition and the required upstream bandwidth of this ONU to OLT in time slot separately.
MPCP entity in the step 602:OLT is processed and is calculated according to local condition and the required upstream bandwidth of this ONU report, obtains the allocated bandwidth result, and this allocated bandwidth result is sent to ONU.
Step 603:ONU sends the upward signal of single wavelength to OLT according to the time slot of stipulating among the allocated bandwidth result.
As seen from the above-described embodiment, the present invention adopts the DWDM technology to expand the closely downstream signal of different wave length of a plurality of spacings in the OLT side at down direction, it is coupled into one road signal transmits, and in ODN, add partial wave demultiplexing device, coupled signal is separated into the downstream signal of a plurality of different wave lengths, and the downstream signal of each wavelength inputed to one group of ONU corresponding to this wavelength, thereby do not needing to change the downlink bandwidth of having expanded the PON system under the prerequisite of ustomer premises access equipment.Further, still adopt the TDM pattern at up direction, the upward signal of transmission single wavelength remains unchanged the upstream bandwidth of former PON system.Because the present invention only need to add new device or upgrade software to OLT and ODN, and needn't change the existing equipment in the network system, thereby so that up-front investment is all protected, has saved equipment cost and the engineering cost of the network capacity extension.
In a word, the above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. a passive optical network PON system is characterized in that, this PON system comprises: optical line terminal OLT, optical distribution ODN and optical network unit ONU;
OLT, adopt dense wave division multipurpose DWDM technology, in OLT side selected center wavelength, wave-length coverage and wavelength interval, in near selected center's wavelength the selected wave-length coverage, according to selected wavelength interval, export the downstream signal of a plurality of different wave lengths, and it is coupled into one road signal, send coupled signal to optical distribution ODN downwards;
ODN receives the coupled signal of OLT output, with the downstream signal of a plurality of different wave lengths separately, and the downstream signal of each wavelength is transferred to one group of optical network unit ONU corresponding to downstream signal of this wavelength downwards;
The downstream signal of the wavelength that this group ONU of each group ONU reception ODN output is corresponding;
Described OLT comprises: a plurality of descending PON ports and the first dense wave division multipurpose band lead to device DWDMBand Pass;
Include PON port transmitter in each descending PON port, each PON port transmitter output is different from the downstream signal of the wavelength of other PON port transmitter, send a DWDMBand Pass downwards to, wherein, the downstream signal of the different wave length of all PON port transmitter outputs is to adopt dense wave division multipurpose DWDM technology to select near centre wavelength in advance in the wave-length coverage, and is determined according to selected wavelength interval;
The one DWDM Band Pass receives the downstream signal of all PON port transmitters, it is coupled into one road signal after, send coupled signal to ODN downwards;
This OLT further comprises 1 two-way PON port;
A described DWDM Band Pass further receives the upward signal of the single wavelength that ODN sends and sends it to two-way PON port;
Two-way PON port comprises PON port transmitter and receiver;
The PON port transmitter of two-way PON port is identical with the PON port transmitter of described descending PON port, and output is different from the downstream signal of the wavelength of other PON port transmitter, and sends a DWDM Band Pass downwards to;
The PON end receiver of two-way PON port receives the upward signal of the single wavelength of DWDM Band Pass transmission;
Comprise in this OLT and all descending PON ports and two-way PON port Multi-point Control Protocol MPCP entity one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute;
The MPCP entity that two-way PON port is corresponding is in work Active state, receive ONU to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation DBA computing engines, calculate the allocated bandwidth result, PON port transmitter by two-way PON port issues the allocated bandwidth result, and it is transmitted to other MPCP entity;
The MPCP entity that each descending PON port is corresponding is in Standby state for subsequent use, forbid moving MPCP agreement and DBA computing engines, receive the allocated bandwidth result that MPCP entity corresponding to two-way PON port calculates, and its PON port transmitter by descending PON port is transmitted downwards.
2. PON system as claimed in claim 1 is characterized in that,
Described ODN further receives the upward signal of the single wavelength that the ONU of time division multiplexing tdm sends, and upwards sends it to OLT.
3. an optical line terminal OLT is characterized in that, this OLT comprises: a plurality of descending PON ports and the first dense wave division multipurpose band lead to device DWDM Band Pass;
Include PON port transmitter in each descending PON port, each PON port transmitter output is different from the downstream signal of the wavelength of other PON port transmitter, send a DWDM Band Pass downwards to, wherein, the downstream signal of the different wave length of all PON port transmitter outputs is to adopt dense wave division multipurpose DWDM technology to select near centre wavelength in advance in the wave-length coverage, and is determined according to selected wavelength interval;
The one DWDM Band Pass receives the downstream signal of all PON port transmitters, it is coupled into one road signal after, send coupled signal to ODN downwards;
This OLT further comprises 1 two-way PON port;
A described DWDM Band Pass further receives the upward signal of the single wavelength that ODN sends and sends it to two-way PON port;
Two-way PON port comprises PON port transmitter and receiver;
The PON port transmitter of two-way PON port is identical with the PON port transmitter of described descending PON port, and output is different from the downstream signal of the wavelength of other PON port transmitter, and sends a DWDM Band Pass downwards to;
The PON end receiver of two-way PON port receives the upward signal of the single wavelength of DWDM Band Pass transmission;
Comprise in this OLT and all descending PON ports and two-way PON port Multi-point Control Protocol MPCP entity one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute;
The MPCP entity that two-way PON port is corresponding is in work Active state, receive ONU to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation DBA computing engines, calculate the allocated bandwidth result, PON port transmitter by two-way PON port issues the allocated bandwidth result, and it is transmitted to other MPCP entity;
The MPCP entity that each descending PON port is corresponding is in Standby state for subsequent use, forbid moving MPCP agreement and DBA computing engines, receive the allocated bandwidth result that MPCP entity corresponding to two-way PON port calculates, and its PON port transmitter by descending PON port is transmitted downwards.
4. OLT as claimed in claim 3 is characterized in that, comprise in the described OLT and all descending PON ports and two-way PON port MPCP entity one to one, respectively descending PON port corresponding to control be connected the upstream bandwidth of the ONU that the PON port connects and distribute;
The MPCP entity that two-way PON port is corresponding is transmitted to all MPCP entities in the PON port set PON-Trunk with up Report frame, the LLID subset LLID-SubSet of the pre-configured non-overlapping copies of each MPCP entity, receive ONU in the LLID-SubSet separately to the local condition of OLT report and required upstream bandwidth, move complete MPCP agreement and Dynamic Bandwidth Allocation DBA computing engines, calculate the allocated bandwidth result, and issue the allocated bandwidth result by the PON port transmitter in the corresponding PON port; A plurality of PON ports form a PON-Trunk;
All MPCP entities share MPCP clock Mpcp_timer and next authorizes time started variable Next_Grant_Start_Time, and upgrade Next_Grant_Start_Time after each run DBA computing engines generates new the mandate;
Mpcp_timer is the MPCP entity of all OLT in the PON-Trunk and the shared MPCP clock of MPCP entity of ONU;
The moment that the initial time Start Time territory of this mandate can be distributed in the next mandate of the Next_Grant_Start_Time indication Grant.
5. OLT as claimed in claim 4 is characterized in that, comprises bridge Bridge in the described OLT;
Each port in the bridge is corresponding one by one with all descending PON ports and two-way PON port, the automatic media access control MAC addresses learning functionality of bridge is in illegal state, according to manageable all ONU of MPCP entity corresponding to each PON port, dispose the LLID subset LLID-Subset of this PON port, each PON port receives the separately interior uplink data frames of LLID-Subset, according to the MAC Address of carrying in the uplink data frames and LLID LLID, upgrade the separately MAC-LLID mapping table of PON port, MAC-LLID mapping table according to each PON port, MAC Address and the bridge port MAC-PORT mapping table of configuration bridge, each bridge port issues downlink data according to the MAC-PORT mapping table of bridge, and the control downlink data is from PON port output corresponding to target ONU.
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| CN102023339B (en) * | 2009-09-22 | 2013-09-11 | 华为技术有限公司 | Mode coupler device, optical module and mode coupling transceiver |
| CN101902666A (en) * | 2010-04-23 | 2010-12-01 | 中兴通讯股份有限公司 | Optical code division multiple access passive optical network system, optical distribution network device and optical line terminal |
| CN101848403A (en) * | 2010-04-23 | 2010-09-29 | 中兴通讯股份有限公司 | Passive optical network system and optical line terminal based on optical code division multiple access multiplexing |
| CN102917282B (en) * | 2012-08-21 | 2016-04-06 | 北京邮电大学 | A kind of priority dynamic wavelength bandwidth allocation methods based on multithreading |
| CN103297166B (en) * | 2013-04-28 | 2015-05-27 | 烽火通信科技股份有限公司 | System and method for mobile and fixed comprehensive connection based on WDM-PON |
| WO2014176791A1 (en) * | 2013-05-03 | 2014-11-06 | 华为技术有限公司 | Method and device for multicarrier division multiplexing system |
| CN104253735B (en) * | 2013-06-27 | 2019-05-24 | 中兴通讯股份有限公司 | Optical network unit, communication system and method |
| CN104363070B (en) * | 2014-11-14 | 2017-11-17 | 上海欣诺通信技术股份有限公司 | A kind of multichannel optical transmission equipment and transmission method |
| CN107493149B (en) * | 2016-06-12 | 2019-03-01 | 天津大学 | Ultra dense wavelength division multiple passive optical network based on the whole network Wavelength synchronous |
| CN108391186B (en) * | 2018-04-19 | 2024-08-27 | 北京邮电大学 | Reconfigurable optical access network system |
| CN109040863B (en) * | 2018-05-29 | 2021-03-30 | 烽火通信科技股份有限公司 | Capacity expansion method and system based on passive optical network system |
| CN110602575B (en) * | 2019-09-02 | 2022-03-25 | 烽火通信科技股份有限公司 | WDM PON wavelength expansion method and system |
| CN111615020A (en) * | 2020-05-05 | 2020-09-01 | 上海云则信息技术有限公司 | Bandwidth extension system based on GEPON system |
| CN115378539A (en) * | 2021-05-20 | 2022-11-22 | 华为技术有限公司 | Processing device, optical communication system and method, processing chip and storage medium |
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