A kind of passive light network transmission system and delay control method thereof
The invention belongs to fiber optic communication field, be specifically related to passive light network transmission system (Passive OpticalNetwork, be called for short PON) and delay control method, more particularly, relate to a kind of EPON system for transmitting and delay control method thereof based on time division multiple access access technology (TDMA).
In the prior art, typical delay control method has following three kinds:
First kind as described in United States Patent (USP) 5341365 and 5469440, and the absolute time delay control algolithm based on the TDMA technology is adopted in time delay control.The upstream multi-frame is made of time delay control frame (HEAD) and valid data frame (BF).The time delay control frame is used for delay testing, after remote equipment PONR receives the delay testing order, remote equipment PONR sends a delay testing pulse train in the time delay control frame, local side apparatus PONC determines the loop time-delay of this remote equipment PONR by detecting this delay testing pulse train, avoids the valid data frame of remote equipment PONR to clash by remote equipment PONR being carried out compensation of delay.In this time delay control algolithm, the control procedure that needs to set up a complexity between local side apparatus PONC and the remote equipment PONR, because long circuit structure complexity and the system reliability of causing of multi-frame length lowers, multi-frame length also can propose restriction to transmission range simultaneously.
Second kind as described in the United States Patent (USP) 5299044, and the carrier wave time delay control algolithm based on the TDMA technology is adopted in time delay control.The upstream multi-frame only is made of the valid data frame, and time delay control is undertaken by a low frequency signal that is modulated on the valid data frame.In this time delay control algolithm, owing to introduce low-frequency modulation signal, inevitably introduce the modulation and demodulation process, signal processing is very complicated, realizes that difficulty is bigger.
The third is as described in the Chinese patent 98113186, and the control algolithm in relative time delay based on the TDMA technology is adopted in time delay control.The upstream multi-frame is made of the valid data frame, and time delay control is undertaken by the frame head of valid data frame.In this time delay control algolithm, because distance measuring signal flows between local side apparatus PONC and remote equipment PONR, and obtain relative loop time-delay by local side apparatus PONC and remote equipment PONR control delay counter, so need to set up the control procedure of a complexity between local side apparatus PONC and the remote equipment PONR, the lower and implementation procedure more complicated of system reliability.
The purpose of this invention is to provide a kind of passive light network transmission system and delay control method thereof based on the time division multiple access access technology, with the adaptability of assurance system to time delay, thereby make delay control method function coverage rate wider, improve the reliability of system, realize simpler.
The present invention realizes so a kind of passive light network transmission system based on the TDMA access technology:
Described system comprises a PON local side apparatus (PONC), optical fiber distributing net (ODN), PON remote equipment (PONR) and PON System Management Unit (PSU);
(PONC) carries out time division multiplexing with input signal by the PON local side apparatus, and the signal of telecommunication after multiplexing is modulated to light signal, this downstream signal is assigned to each PON remote equipment (PONR) by optical fiber distributing net (ODN), and PON remote equipment (PONR) comes out the Signal Separation of this PONR by tap;
PON remote equipment (PONR) is with the input signal multiple connection that happens suddenly, and the burst time slot signal of telecommunication after the multiple connection is modulated to light signal, the burst time slot signal of all PON remote equipments (PONR) carries out the allos light signal by ODN and synthesizes, give each PON local side apparatus (PONC) with the upward signal after synthetic, PON local side apparatus (PONC) comes out the Signal Separation of these all PON remote equipments (PONR) by the burst tap;
In order to carry out avoiding the burst luminous signal of different PON remote equipments (PONR) to clash when the allos light signal synthesizes at ODN, the time delay of PON remote equipment (PONR) burst luminous signal need be controlled, and the time delay controlled function realizes by system's location delay controller that PON System Management Unit (PSU) is controlled this PONR.
In the aforesaid system; send to the upward signal of local side apparatus (PONC) by remote equipment (PONR); its multi-frame structure is made of valid data frame (BF#Ts); each valid data frame is made up of expense and letter sign indicating number; for fear of the collision of valid data frame (BF#Ts), must leave necessary protection between the valid data frame (BF#Ts) at interval.
The PON local side apparatus (PONC) of aforesaid passive light network transmission system comprises:
Be used to realize the electrical to optical converter of even electric light translation function, the optical-electrical converter of photoelectric converting function is used to realize to happen suddenly, be used to realize the multiplexer of homogeneous interconnection function, be used to realize the to happen suddenly coupler of branch connection function is used for the local side micro-control unit that PON local side apparatus (PONC) is managed and is used to carry out the impact detector of collision detection;
Wherein, electrical to optical converter links to each other with optical fiber distributing net (ODN) with optical-electrical converter, one end of local side micro-control unit links to each other with PON System Management Unit (PSU), the other end links to each other with coupler, impact detector and multiplexer by control bus, optical-electrical converter is sent to coupler and impact detector respectively with received signal, and multiplexer is sent to electrical to optical converter with signal.
The PON remote equipment (PONR) of aforesaid passive light network transmission system comprises:
The electrical to optical converter of electric light translation function is used to realize to happen suddenly, be used to realize the optical-electrical converter of even photoelectric converting function, the multiplexer of multiple connection function is used to realize to happen suddenly, be used to realize evenly dividing the coupler of connection function, be used for the micro-control unit that PON remote equipment (PONR) is managed and be used for that system uplink is located the system that controls that delays time locating delay controller;
Wherein, electrical to optical converter links to each other with optical fiber distributing net (ODN) with optical-electrical converter, one end of far-end micro-control unit links to each other with PON System Management Unit (PSU), the other end links to each other with multiplexer with coupler, system's location delay controller by control bus, optical-electrical converter sends acknowledge(ment) signal to coupler, coupler outputs signal to system's location delay controller, and system's location delay controller outputs signal to multiplexer, and the multiplexer signal is sent to electrical to optical converter.
The delay control method that the present invention proposes adopts the control method in relative time delay, realizes that by system's location delay controller of PON System Management Unit (PSU) control PON remote equipment (PONR) it may further comprise the steps:
1, define system position length L is a multi-frame length;
2, PON System Management Unit (PSU) sends reading order to the local side micro-control unit;
3, impact detector detects Ts PONR burst time slot signal;
4, the local side micro-control unit reads testing result from impact detector, and replys to PON System Management Unit (PSU);
5, PON System Management Unit (PSU) carries out discriminatory analysis to detection;
6, PON System Management Unit (PSU) sends judged result to the far-end micro-control unit;
7, the far-end micro-control unit is controlled the last line delay of system by system's location delay controller.
Implement passive light network transmission system and the delay control method thereof based on the time division multiple access access technology of the present invention, collision detection result by impact detector, by the control of delaying time of system location delay controller, avoid in the prior art time delay control procedure complicated between the PONC and PONR, system configuration is simple, lower design cost, improved the reliability of system.
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.
Fig. 1 is the formation schematic diagram of passive light network transmission system;
Fig. 2 is an absolute delay control method data flow multi-frame structure schematic diagram in the prior art;
Fig. 3 is the multi-frame structure schematic diagram of the used upward signal of the present invention;
Fig. 4 is the used passive optical network local side apparatus PONC structural representation of the present invention;
Fig. 5 is the used EPON remote equipment PONR structural representation of the present invention;
Fig. 6 is the used time delay control flow schematic diagram of the present invention.
Passive light network transmission system as shown in Figure 1, it comprises a PON local side apparatus (PONC) 1, optical fiber distributing net (ODN) 2, PON remote equipment (PONR) 3 and PON System Management Unit (PSU) 4, and a plurality of PON remote equipments (PONR) 3 link to each other with a PON local side apparatus (PONC) 1 by optical fiber distributing net (ODN) 2; PON System Management Unit (PSU) 4 links to each other with PON remote equipment (PONR) 3 with PON local side apparatus (PONC) 1 by management interface.
Fig. 2 is the data flow multi-frame structure of the upward signal that adopts in the Chinese patent 98113186, and it is by frame head HEAD and a series of valid data frame BF#1, BF#2 ..., BF#Ts constitutes, its length L=10ms.
Fig. 3 has provided and proposed by the invention has sent to the upward signal of local side apparatus (PONC) by remote equipment (PONR), and its multi-frame structure is by a series of valid data frame BF#1, BF#2 ..., BF#Ts constitutes, its length L=125us.
As shown in Figure 4, the concrete connected mode of local side apparatus (PONC) 1 is: electrical to optical converter 101 links to each other with optical fiber distributing net (ODN) 2 with optical-electrical converter 102, local side micro-control unit 105 links to each other with PON System Management Unit (PSU) 4, the burst electrical signal data bag that optical-electrical converter 102 will receive is sent to coupler 104 and impact detector 106 be used to happen suddenly tap and collision detection respectively, local side micro-control unit 105 is by control bus and coupler 104, impact detector 106 links to each other with multiplexer 103, and the downlink electrical signal data bag that multiplexer 103 is good with multiple connection is sent to electrical to optical converter 101 and is used for the electric light conversion.
As shown in Figure 5, the concrete connected mode of remote equipment (PONR) is: electrical to optical converter 301 links to each other with optical fiber distributing net (ODN) 2 with optical-electrical converter 302, far-end micro-control unit 305 links to each other with PON System Management Unit (PSU) 4, coupler 304 output system framing signal control system location delay controller 306, system's location delay controller 306 output systems relocate signal controlling multiplexer 303, far-end micro-control unit 305 is by control bus and coupler 304, system's location delay controller 306 links to each other with multiplexer 303, and the uplink burst electrical signal data bag that multiplexer 303 is good with multiple connection is sent to electrical to optical converter 301 and is used for the electric light conversion.
Time delay control for Ts PONR realizes that by following steps its flow chart is by shown in Figure 6:
1. define system position length L is a multi-frame length, system's location initial point is produced by PON local side apparatus (PONC) 1, and send PON remote equipment (PONR) 3 to by downlink multiframes, in the system each unit all reference system location initial point carry out work, the location of each unit in the system can be described by the relative distance N of itself and system's location initial point, and N is not more than L;
2.PON System Management Unit (PSU) 4 order local side micro-control units 105 read Ts PONR collision status message;
3. each PONR burst time slot signal of 106 couples of Ts of impact detector detects.If detect this signal, then Ts PONR burst of impact detector 106 output time slot signal is in happen suddenly time slot signal and system of time delay state of a control and Ts PONR and locatees the relative distance N (Ts) of initial point, and N (Ts) is not more than the position length L of system; If do not detect this signal, then Ts PONR burst of impact detector 106 outputs time slot signal is in the time delay collision status.The object of the detection of impact detector 106 is the time slot address of PONR burst time slot signal, and its length is 8 bits, adopts the self-checking code type to be used for error-detection error-correction, and the cycle is the position length L of system.
4. local side micro-control unit 105 reads the collision status of Ts PONR from impact detector 106, and collision status is replied to PON System Management Unit (PSU) 4.
5. be time delay control as collision status, PON System Management Unit (PSU) 4 is analyzed the current system location time-delay length M (Ts) of these PONR, and this M (Ts) is not more than the position length L of system and its value and is the difference sum with the position length L of system and this PONR relative distance of M (Ts) last time; Simultaneously PSU (4) sends current M (Ts) the far-end micro-control unit 305 of this PONR to, and far-end micro-control unit 305 makes the up state of activation that is in by the up location time-delay of system's location delay controller 306 control system.
6. be the time delay collision as collision status, far-end micro-control unit 305 these message of broadcasting of other PONR of PON System Management Unit (PSU) 4 in system, far-end micro-control unit 305 makes the up deactivation status that is in by the up location of system's location delay controller 306 shutdown systems.
7. when being in state of activation,, send the burst time slot signal by being delayed time in the system location; When being in deactivation status,, do not send the burst time slot signal by the system location is locked.