Packet Header Compression In Wireless Network

Recently, types of services could be carried on mobile wireless network. Besides ofsome traditional telecommunication services, other services also involved in mobileterminal, such as VOIP, multimedia, videos, and so on. The development of the IPtechnology and the process of Full-IP network are speeded up, benefited by theseservices. In order to carried these real time services in TCP/IP network, RTP protocol isintroduced, to ensure the real-time. So a typical VOIP packet is composed of40bytespacket header (20bytes of a IPv4header,8bytes of a UDP header, and20bytes of aRTP header), but the payload data (voice data) are often only15-20bytes. Obviously,these typical packets severely cause the waste of the wireless bandwidth resource.So in order to improve the wireless resource utilization, it is necessary to compressthe packet header. Recently, RObust Header Compression (ROHC) introduced as a newstandard by IETF, has been designed to compress the packet headers, which carried inwireless link.In this paper, the algorithms used in ROHC, the main header compression processand the base architecture of ROHC system are well introduced detaily. ROHC protocolcould be used to compress not only the IP/UDP/RTP packets but also the IP/UDP and IPpackets, it’s has an extensible architecture.Beside the introduction of the basic ROHC architecture, we also propose someoptimization based on ROHC architecture at the end of this paper, such as UDPChecksum reusing、how to establish the TS_STRIDE and TS_OFFSET effectively. Atlast, we introduce a new video stream architecture which linked the video encodingalgorithm with the ROHC system. This architecture could improve the reliability andthe quality of video stream service which carried on wireless network, and without anyinfluence of ROHC compression effectiveness.