Designing And Implementation On Data Packet Compressing Algorithm In PDSN System

In PDSN system , data packet between MS and PDSN compressed by compressing algorithm can reduce the size of the transmitting packet, improve the efficiency of data transmission and support large number of simultaneous connected users. This paper makes use of MPPC algorithm to compress transmitting data in PDSN system and implements the function methioned above.First, this auther focuses on the expatiation of the working principle and system structure of PDSN and analyzing the dada transmission between MS and PDSN. With a combination of the design principles and characteristics of PDSN, a method for compressing data packet using MPPC compressing algorithm is put forward. After studying PPP protocol and MPPC compressing standards, an algorithm using packet matching sliding window buffer to code and decode is provided. Considering not making a great change of current PDSN system, a MPPC compressing module is designed and the function to compress data packet through Vxworks platform is implemented. Finally, with the compressing performance test, the testing results are presented. Through this new algorithm,the average size of data packet is around 50% of original one and the data transmitting velocity nearly doubled. Consequently, it can greatly improve the performance of PDSN.