CN1980106A - Multi-business multiplexing method and optical transmitting system - Google Patents

Abstract

A multiplexing method supporting multi-service access and an optical transmission system. Design multiple synchronous channels with different capacities according to the service characteristics, each channel can multiplex one or more channels of the same type of service signals, and the service signals do not need more processing except for the necessary rate adaptation, after being framed and coded by the synchronous channel can be transmitted on the optical path. The invention can efficiently perform multiplexing of different granularity services and ensure the transmission quality of each service; the multiplexing process is simple, can be realized in a single integrated circuit chip, and the realized system has good economy and high reliability.

Description

Multi-service multiplexing method and optical transmission system

Technical Field The present invention relates to an optical transmission multiplexing method and system supporting multi-service access. It belongs to the technical field of optical access and transmission.

Background technology At present, the common practice of transmitting data services on SDH networks is to map data services to In the SDH virtual container. The multi-service transmission platform MSTP is a platform that provides data service functions on SDH equipment through technologies such as GFP and VC virtual concatenation.

The problems existing in MSTP at present are: ① The current MSTP implements multi-service transmission based on SDH, and the block frame of SDH is composed of vertical 9 rows and horizontal 270 column bytes. The segment overhead and management unit pointer are placed in the first 9 bytes of each line, and its frame overhead accounts for more than 3% of its total capacity, and many overheads have no practical use. ②The traditional SDH system uses a virtual container (VC) with a fixed bit capacity. Each type of virtual container carries a fixed-rate signal to transmit service data. When transmitting data services, there is a problem of low bandwidth utilization. For example, when using VC4 channels to transmit 100Mb/s Ethernet signals, the bandwidth utilization rate is only 67%, and the other 33% of the bandwidth is not utilized. ③ The current MSTP data service must go through complex mapping, positioning and multiplexing according to SDH regulations, and finally be converted into multiple VC4 or VC12 particles that SDH can handle before it can be transmitted in SDH network. This method has many steps and a complicated process, and the mapping process requires overhead. ④ The VC particles assigned to each data port in the current MSTP are fixed and cannot be dynamically adjusted according to the actual traffic of the network. The minimum service interface capacity is 2M, which cannot directly support lower-speed services, but requires additional adaptation function units, which increases complexity and costs. ⑤ The above ③ and ④ determine that this technology requires the selection of multiple integrated circuit chips to achieve different functions. From the perspective of the basic composition of the system, its design and implementation costs are relatively high, and it is difficult to popularize in access networks with high economic requirements.

SUMMARY OF THE INVENTION The object of the present invention is to provide an economical, efficient multiplexing method that supports multi-service access, and to implement an optical transmission system based on the above-mentioned shortcomings of the prior art.

The basic principle of the present invention is to design the rate and quantity of channels according to the service type and capacity requirements of multi-service access and transmission. Channel rate = business rate + redundant rate, the redundant part provides rate adaptation and keeps each channel synchronous. Rate adaptation adopts a positive code rate adjustment method, each channel forms an integer multiple rate relationship, and the channel rate is as close to the service rate as possible, that is, the redundant rate is as small as possible. In addition, in consideration of further improving efficiency and reducing implementation difficulty, each service is grouped according to its rate characteristics, and services of the same group are adapted to the same channel to reduce channel types. The number of channels can meet the needs of the service type and capacity required for access and transmission.

The present invention designs a plurality of synchronous channels with different capacities according to the service characteristics. Since each channel is in a synchronous relationship, it can synchronously form frames and form a frame structure with byte as the unit. Consider simplifying the processing of frame synchronization, frame alignment signals and other overhead using one lane.

The entire multiplexing process of the present invention only has two processes of rate adaptation and synchronous framing, and all services enter the synchronous channel after one rate adaptation, so the complexity is greatly reduced, and multiple services can be realized in a single integrated circuit chip reuse, and can improve the economy and reliability of system implementation.

Once formed, the channel of the present invention contains one or a group of services. Each channel is independent of each other, and the service signals in the channel are also independent of each other, and are not affected by the format and rate of other services, which can ensure the transmission performance and security of services.

Since the present invention adjusts various and different-rate service signals in their corresponding synchronous channels, framing does not bring new overhead except for adding necessary frame positioning signals, and the efficiency of realizing multiplexing of services with different granularities is improved. improve.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a schematic structural diagram of an optical transmission system of the present invention;

Fig. 2 is a functional structure diagram of the multi-service multiplexing platform 150Mbit/s system of the present invention.

1 is a schematic diagram of the optical transmission system of the present invention. Functionally, it is divided into a service interface module (101), a multi-service multiplexing module (102), an optical transceiver module (103) and a physical link optical fiber. The interface module realizes the access of various services, the multiplexing module multiplexes various services, and converts the multiplexed electrical signal into an optical signal through the optical transceiver module, and then sends it to the optical fiber line, and does the opposite after reaching the other end transformation, and demultiplexing to generate various services.

The multi-service multiplexing method of the present invention is based on multi-channel technology, the rate and data form of each service can be different, and the total transmission rate can be selected based on the needs of service capacity. The actual design should also consider the cost of the device, and it is advisable to choose a general-purpose device. Provided here is a design and realization based on 150Mbit/s system.

Fig. 2 is a functional structural diagram of the 150Mbit/s system. In this design, arrange 101Mbit/s (48×2112kbit/s), 25Mbit/s (12×2112kbit/s), and 2112kbit/s three kinds of synchronous channels. 100M Ethernet service enters Ethernet interface (label 201), enters channel 1 (101Mbit/s) after adaptation (label 206); 25M video information stream enters ATM interface (label 202), enters channel after adaptation (label 207) 2 (25Mbit/s); 2M data service enters E1 interface (label 203), and enters channel 3 (2112kbit/s) after adaptation (label 208); N×64 data service enters N×64 interface (label 204), asynchronous The serial data signal enters the serial port (label 205), and both can be adapted together (label 209) and enters channel 4 (2112kbit/s); the frame overhead (label 210) adopts a 2112kbit/s channel, including frame alignment signal and error Code monitoring, the 2112kbit/s frame overhead channel is also responsible for transmitting signals such as monitoring, network management, switching and official duties. These channels are combined and frame overhead is inserted to form a 150Mbit/s signal (label 211). The scrambling method is used for encoding, so that the code rate will not increase.

The frame overhead channel accounts for less than 2% of the total capacity (2.112÷150×100%=1.4%)

The multiplexing efficiency of each service of the channel is as follows:

100M Ethernet service overhead = (2.112×48-100)÷100×100%＝1.376%≈1.4%

2M data service overhead = (2.112-2.048) ÷ 2.048 × 100% = 3.125% ≈ 3.1%

Business multiplexing efficiency = (1-2.112/150) × 100% = 98.6%

Therefore, assuming that Ethernet services account for 2/3 and 2M services account for 1/3, then

The total multiplexing efficiency of the system = (2/3×98.6%+1/3×96.9%)×98.6%≈96.7%

However, even if the traditional SDH transmits all E1 TDM services, the service transmission efficiency can only reach 84% at most, and the efficiency will be lower if multi-service transmission is carried out.

For the 600Mbit/s system, five 101Mbit/s channels and multiple 101Mbit/s or less bandwidth channels can be arranged by using the above method, and the combination forms can be varied.

For higher capacity, you can choose 1.25Gbit/s system or 2.5Gbit/s system, which can provide 1000Mbit/s channel to support Gbit Ethernet services.

Claims (6)

1, a kind of multiplexing method of supporting that multi-service inserts is characterized in that designing at business characteristic the synchronizing channel of a plurality of different capabilities can efficiently carrying out the multiplexing of variable grain degree business.

2, the multiplexing method that said support multi-service inserts as claim 1, it is once adaptive to it is characterized in that every kind of business only needs, and can carry out synchronous multiplexing, and service signal does not need more multiprocessing except the interface rate of necessity is adaptive.

3, the multiplexing method that inserts as the said support multi-service of claim 1 is characterized in that the service signal that each passage can multiplexing one or more same-type.

4, the multiplexing method that said support multi-service inserts as claim 1 is characterized in that supporting simultaneously the access and the transmission of E1, asynchronous serial data and Ethernet service.

5, the multiplexing method that said support multi-service inserts as claim 1 is characterized in that realizing the multi-business multiplexing function in monolithic integrated circuit chip.

6, adopt as the optical transmission system of the multiplexing method realization that the said support multi-service of claim 1 inserts, it is characterized in that realizing the multi-business multiplexing and the optical transmission of multichannel E1, asynchronous serial data, linear speed 100M Ethernet.

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