Main purpose of the present invention is: a kind of new comprehensive transmission ATM business and the method and apparatus of STM business are provided, to improve the transmission system bandwidth availability ratio, improve service transmission performance, reduce cost.
The invention provides a kind of method that is used on the broadband passive optical network transmission convergence layer comprehensive Asynchronous Transfer Mode and Synchronous Transfer Mode business, wherein broadband passive optical network PON hierarchy is such: top is the upper-layer protocol of service-oriented application; Be circuit-mode CM (CIRCUIT MODE) layer below the upper-layer protocol of Synchronous Transfer Mode STM business, this circuit-mode layer is responsible for finishing multiplexing, cross connect function; Group mode circuit-mode business professional and/or that make circuit simulation is referred to as Asynchronous Transfer Mode ATM business, be the adaptive AAL layer of Asynchronous Transfer Mode ATM cell below the upper-layer protocol of Asynchronous Transfer Mode business, finish that high layer information is adapted to the Asynchronous Transfer Mode ATM cell and the Asynchronous Transfer Mode ATM cell reassembles into the high-level protocol information form; Be Asynchronous Transfer Mode ATM layer below the adaptive AAL layer of described Asynchronous Transfer Mode ATM cell, be responsible for carry out multiplexed, the interconnection of Asynchronous Transfer Mode ATM cell, generation and the extraction and the general flow control function of letter head; Described Asynchronous Transfer Mode ATM layer and described circuit-mode CM layer are downwards to assemble the TC sublayer towards the transmission of broadband passive optical network PON physical layer side by side, finish bit, byte, frame synchronization and burst synchronization, range finding, allocated bandwidth and security guarantee function; Be the physical medium sublayer below the described Transmission Convergence Sub-layer, carry out light/electric conversion, wavelength multiplexing, optical fiber linkage function.It is adaptive that the Synchronous Transfer Mode business is not made Asynchronous Transfer Mode ATM in described Asynchronous Transfer Mode cell adaptation layer, directly the Asynchronous Transfer Mode ATM cell of Synchronous Transfer Mode STM service signal and Asynchronous Transfer Mode ATM business is mapped in the broadband passive optical network PON frame together and assemble the TC sublayer in described transmission; Wherein said broadband passive optical network PON frame is made up of Synchronous Transfer Mode STM time slot and Asynchronous Transfer Mode ATM cell and physical layer overhead; The frame length of described broadband passive optical network PON frame is n a times of 125 μ s, and n is a positive integer; The clock of described broadband passive optical network PON and the business network interface SNI clock synchronization that Synchronous Transfer Mode STM service signal is provided.
During transmission, the STM signal is cached in STM first-in first-out fifo queue, and the ATM service signal is cached in ATM first-in first-out fifo queue, the output of these two formations regularly is read into the transmit queue of broadband P ON so that form broadband P ON frame under the control that transmits control signal that produces according to broadband P ON frame structure, finish the comprehensive of ATM signal and STM signal, its output further processing through fail safe and physical medium sublayer transfers to receiving terminal; After the processing of physical medium sublayer and fail safe, obtain ATM and STM integrated signal at receiving terminal, by the reception control signal control that produces according to broadband P ON frame structure the STM signal is read into STM and receive fifo queue, ATM cell reads into ATM and receives fifo queue, finishes separating of STM and ATM signal.The transmission of circuit-mode business is that the time slot with a length n byte is a unit, is called the STM time slot, and n is a positive integer; At the PON system clock of OLT generation with the clock synchronization of the SNI that the circuit-mode business is provided, ONU extracts clock from the signal flow that OLT transmits.STM timeslot number in each PON frame and position thereof are by the system management assignment, and total how many STM time slots of each ONU and position thereof are also by the system management assignment.
The present invention also provides the comprehensive ATM on Transmission Convergence TC sublayer of employing said method and the passive optical network PON device A CTC PON of STM business, described equipment is made up of optical line terminal OLT and optical network unit ONU and tree-like optical distribution network ODN, wherein said optical line terminal OLT is made up of descending transtation mission circuit of OLT and the up receiving circuit of OLT, and described optical network unit ONU is made up of up transtation mission circuit of ONU and the descending receiving circuit of ONU; Wherein when sending, Synchronous Transfer Mode STM signal is cached in Synchronous Transfer Mode STM and sends among the FIFO, and Asynchronous Transfer Mode ATM service signal is cached among the Asynchronous Transfer Mode ATM transmission FIFO, its output regularly is read into the transmit queue of broadband passive optical network PON under the control that transmits control signal that sending controling circuit produces according to broadband passive optical network PON frame structure, so that form broadband passive optical network PON frame, thereby obtain the integrated signal of Asynchronous Transfer Mode ATM signal and Synchronous Transfer Mode STM signal.
It is adaptive that the STM signal is not made AAL, become the PON frame but directly be input to descending transmission FIFO by frame structure with ATM cell, this frame structure professional at the comprehensive ATM of PON TC layer and the circuit-mode business is called the ACTC_PON frame by us, and is simple in structure, and cost is low and improved performance.For example, the STM signal in the propagation delay time of ACTC_PON less than 250 μ s, much smaller than the time delay of circuit simulation mode, and irrelevant with bandwidth availability ratio, the contradiction when having solved the circuit simulation mode between propagation delay time and the bandwidth availability ratio.Moreover, owing to there is not ATM adaptive, just there is not the letter header overhead of ATM cell yet, therefore, the transmission bandwidth utilance of ACTC_PON is than the ATM_PON height based on pure ATM cell.
Owing to adopt technique scheme, can solve cost-effectively the circuit-mode business in broadband P ON with the comprehensive access of ATM business, performance and price compare circuit-mode professional insert by circuit simulation high.
The present invention is further described below in conjunction with drawings and Examples.
The present invention from the hierarchical mode angle of Fig. 1 explanation is transfer circuit mode business and ATM business how.Broadband passive optical network PON hierarchy is such: top is the upper-layer protocol that service-oriented is used; Be circuit-mode CM layer below the upper-layer protocol of Synchronous Transfer Mode STM business, this circuit-mode layer is responsible for finishing multiplexing, cross connect function; Group mode circuit-mode business professional and/or that make circuit simulation is referred to as Asynchronous Transfer Mode ATM business, be the adaptive AAL layer of Asynchronous Transfer Mode ATM cell below the upper-layer protocol of Asynchronous Transfer Mode business, finish that high layer information is adapted to the Asynchronous Transfer Mode ATM cell and the Asynchronous Transfer Mode ATM cell reassembles into the high-level protocol information form; Be Asynchronous Transfer Mode ATM layer below the adaptive AAL layer of described Asynchronous Transfer Mode ATM cell, be responsible for carry out multiplexed, the interconnection of Asynchronous Transfer Mode ATM cell, generation and the extraction and the general flow control function of letter head; Described Asynchronous Transfer Mode ATM layer and described circuit-mode CM layer are downwards to assemble the TC sublayer towards the transmission of broadband passive optical network PON physical layer side by side, finish bit, byte, frame synchronization and burst synchronization, range finding, allocated bandwidth and security guarantee function; Be the physical medium sublayer below the described Transmission Convergence Sub-layer, carry out light/electric conversion, wavelength multiplexing, optical fiber linkage function.
It is adaptive that the Synchronous Transfer Mode business is not made Asynchronous Transfer Mode ATM in described Asynchronous Transfer Mode cell adaptation layer, directly the Asynchronous Transfer Mode ATM cell of Synchronous Transfer Mode STM service signal and Asynchronous Transfer Mode ATM business is mapped in the broadband passive optical network PON frame together and assemble the TC sublayer in described transmission; Wherein said broadband passive optical network PON frame is made up of Synchronous Transfer Mode STM time slot and Asynchronous Transfer Mode ATM cell and physical layer overhead; The frame length of described broadband passive optical network PON frame is n a times of 125 μ s, and n is a positive integer; The clock of described broadband passive optical network PON and the business network interface SNI clock synchronization that Synchronous Transfer Mode STM service signal is provided.
Upper-layer protocol towards the circuit-mode business becomes PON frame at the PON Transmission Convergence Sub-layer with the ATM business through the processing of circuit-mode CM layer, and multiplexing function is mainly carried out in the processing of CM layer, business is dredged and the cross connect function that disposes etc.
During transmission, the STM signal is cached in STM first-in first-out fifo queue, and the ATM service signal is cached in ATM first-in first-out fifo queue, the output of these two formations regularly is read into the transmit queue of broadband P ON so that form broadband P ON frame under the control that transmits control signal that produces according to broadband P ON frame structure, finish the comprehensive of ATM signal and STM signal, its output further processing through fail safe and physical medium sublayer transfers to receiving terminal; After the processing of physical medium sublayer and fail safe, obtain ATM and STM integrated signal at receiving terminal, by the reception control signal control that produces according to broadband P ON frame structure the STM signal is read into STM and receive fifo queue, ATM cell reads into ATM and receives fifo queue, finishes separating of STM and ATM signal.The transmission of circuit-mode business is that the time slot with a length n byte is a unit, is called the STM time slot, and n is a positive integer; At the PON system clock of OLT generation with the clock synchronization of the SNI that the circuit-mode business is provided, ONU extracts clock from the signal flow that OLT transmits.STM timeslot number in each PON frame and position thereof are by the system management assignment, and total how many STM time slots of each ONU and position thereof are also by the system management assignment.
What Fig. 2 a and Fig. 2 b described is to realize electric theory diagram of the present invention.When system initialization, processor 4 is responsible for and the communicating by letter and Message Processing of system network management, requires configurating downlink sending controling circuit 5, descending reception control circuit 28, up medium access control MAC (MediumAccess Control) control circuit 67 and up reception MAC control circuit 44 according to system network management.Shown in Fig. 2 a, the signal that descending transtation mission circuit 11 of OLT and the descending receiving circuit 29 of ONU and ODN12 finish down direction transmits, and promptly the signal of OLT to ONU direction transmits.In the descending transtation mission circuit 11 of OLT, the STM signal that the STM signal bus comes is input to descending STM and sends FIFO1; Send FIFO2 and be input to descending ATM from the ATM cell that the ATM cell bus is come; Configuration and system frame structure according to system network management regularly is sent to descending transmission FIFO7 with PLOAM cell, STM signal and the ATM cell that down physical layer Operation Administration and Maintenance PLOAM (Physical Layer Operation Administration Maintenance) cell generation circuit 3 is produced then, and wherein said PLOAM cell is used for frame synchronization, physical layer is safeguarded, moved and management; The output of described descending transmission FIFO7 is carried out parallel/serial conversion in parallel/serial change-over circuit 8, in scrambler circuit 9, carry out scrambler, and in electricity/light change-over circuit 10, carry out electricity/light conversion, deliver to optical distribution network 12 at last, so that be transferred to the descending receiving circuit 29 of ONU.In the descending receiving circuit 29 of ONU, the light signal that receives at first carries out light/electricity conversion in light/power conversion circuit 21, utilize timing extraction circuit 23 to extract bit clock, in scrambling code decoding circuit 22, carry out descrambling code, utilize then and realize downlink frame synchronous and string and conversion in the synchronous and serial/parallel change-over circuit 24 of downlink frame; Deliver to descending STM at following STM signal of descending reception control circuit 28 controls and receive FIFO25, and ATM cell is delivered to descending ATM receive FIFO26, STM signal bus and ATM cell bus are delivered in their output respectively, thereby finish comprehensive on the TC layer of STM signal and ATM cell on the down direction.In addition, descending PLOAM is imported into descending PLOAM receiving circuit under descending reception control circuit 28 controls, and its output is delivered to processor 4 so that carry out the function of physical layer Operation, Administration and Maintenance aspect.
Shown in Fig. 2 b, the signal that up transtation mission circuit 68 of ONU and the up receiving circuit 47 of OLT and ODN12 finish up direction transmits, and promptly the signal of ONU to OLT direction transmits.In the up transtation mission circuit 68 of ONU, the STM signal that the STM signal bus comes is input to up STM and sends FIFO64, is input to up ATM from the ATM cell of ATM cell bus and sends FIFO65; Respectively up STM being sent the STM signal of FIFO64 output, up ATM under the control of up MAC control circuit 67 sends the ATM signal of FIFO65 output and up PLOAM cell and mini-slot and produces up PLOAM cell that circuit 66 produced and be used to report the mini-slot of ONU bandwidth request to be sent to up transmission FIFO63; Expense (the OVERHEAD that is used for the time division multiple access tdma communication is inserted in the output of described up transmission FIFO63 in the insertion of TDMA expense, scrambler and parallel/serial change-over circuit 62, write a Chinese character in simplified form into OH), and under the clock effect that comprises bit clock, byte clock and frame pulse that utilizes downstream signal to extract, carry out scrambler, and carry out parallel/serial conversion; In burst mode electricity/light modular converter 61, carry out the electric light conversion.Light signal after the conversion is delivered to optical distribution network 12, and transfers to the up receiving circuit 47 of OLT.The light signal that the up receiving circuit 47 of OLT receives carries out opto-electronic conversion in burst mode light/electric modular converter 46, the output of described burst mode light/electric modular converter 46 is transferred to burst synchronization and descrambling circuit 45; In burst synchronization and descrambling circuit 45, utilize the clock comprise bit clock, byte clock and frame pulse to carry out synchronously and the parallel signal is synchronously carried out descrambling code; Data behind the descrambling are delivered to up STM respectively and are received FIFO41, up ATM reception FIFO42 and up PLOAM and mini-slot reception FIFO43 under the control of up reception MAC control circuit 44; The output that up STM receives FIFO41 transfers to subsequent process circuit through the output that STM signal bus and up ATM receive FIFO42 through the ATM signal bus, thereby finishes comprehensive on the TC sublayer of ACTC_PON of up direction STM signal and ATM cell.
The ACTC_PON system frame structure specifically is such: the up-downgoing frame length is the positive integer times (positive integer preferably gets 1,2,3 and 4) of 125 μ s here; First and the middle several slots unit of downlink frame is to be used for downlink frame synchronously and physical layer is moved, the PLOAM cell of maintenance and management OAM, and all the other are configured to by system network management is ATM cell or STM time slot (length is granularity with the byte); Uplink frame is added to be used for the expense composition that the TDMA mode is communicated by letter by ATM cell or STM time slot or PLOAM cell or mini-slot (length is granularity with the byte).The position of ATM cell, STM time slot, PLOAM cell and mini-slot and quantity are determined by system network management and MAC agreement.
The clock of whole ACTC_PON system and the clock synchronization that the SNI of circuit-mode business is provided.Specifically: the clock generation circuit at the OLT place produces and 2.048MHz, the 8KHz of the SNI strict synchronism that the circuit-mode business is provided and the clock of 155.52MHz.2.048MHz and the 8KHz clock is used for the STM signal processing; 155.52MHz clock is the systematic bits clock.From the code stream that OLT transmits, extract clock and the frame frequency clock of 155.52MHz at the ONU place, be used for the STM signal processing by the 2.048MHz clock that the frame signal frequency multiplication produces and OLT is synchronous and use.The clock recovery problem of the complexity when not having circuit simulation like this.
Shown in Figure 3 is the frame structure of first embodiment of the invention.In this embodiment, the transmission rate of up-downgoing is 155.52Mb/s, and the up-downgoing frame length is 125 μ s.Descending PLOAM is used for the expense of physical layer operation maintenance and management; comprise mandate to each ONU utilized bandwidth, frame synchronous byte, OAM message, dynamically byte is adjusted in range finding, control byte, official traffic expense etc. are switched in protection; descending PLOAM cell is 49 bytes; ATM cell and STM time slot are 53 byte longs; totally 44, its quantity is specified by system network management respectively.Uplink frame contains 43 the up PLOAM cell, ATM cell, the STM time slots that add 3 byte TDMA expenses (OH) altogether, cuts apart time slot and up public affair speech channel and spare bytes.Wherein cutting apart time slot is 53 byte longs, is made up of n mini-slot, and n is a positive integer.Cutting apart the position of time slot and quantity and mini-slot counts n and is determined by system network management.Up PLOAM, ATM cell and 53 byte longs of STM time slot, their quantity is determined by system network management.Up PLOAM is used for the expense of physical layer operation maintenance and management, comprises OAM message, protects and switch control byte, official traffic signaling consumption etc.; Cut apart the MAC agreement that time slot is used for system.Shown in Figure 4 is the frame structure of second embodiment of the invention.In this embodiment, the transmission rate of up-downgoing is 155.52Mb/s, and the up-downgoing frame length is 250 μ s.Descending PLOAM cell is 49 byte longs, have 4, the expense that is used for physical layer operation maintenance and management comprises that byte is adjusted in mandate, frame synchronous byte, OAM message, the dynamic range finding to each ONU utilized bandwidth, control byte, official traffic expense etc. are switched in protection; ATM cell and STM time slot are 53 byte longs, and both have 88, and they divide other quantity to be specified by system network management.Uplink frame contains 86 altogether and adds up PLOAM cell, ATM cell, the STM time slot of 3 byte TDMA expenses and cut apart time slot, and their quantity is determined by system network management; The up public affair speech channel and the spare bytes that also have 2 22 bytes in addition.Up PLOAM, ATM cell and STM time slot and cut apart equal 53 byte longs of time slot.Up PLOAM is used for the expense of physical layer operation maintenance and management, comprises OAM message, protects and switch control byte, official traffic signaling consumption etc.; Cut apart the MAC agreement that time slot is used for system.