ROHC+: a new header compression scheme for TCP streams in 3G wireless systems

摘要

An actual trend in the telecommunication world is the proposal of a universal telecommunication system deriving from the convergence between mobile telephony and the Internet. Such a system will presumably exploit both wired and wireless parts, a network platform totally based on a TCP/IP architecture. However, the encapsulation process of TCP/IP layers produces packets whose payload size, for particular services, is a small percentage of the whole packet size (high overhead-services), so that, a significant part of radio channel bandwidth (the most expensive and limited resource of the whole wireless system) is used for header transmission. For these reasons it is of primary importance for the adoption of a header compression scheme to be able to reduce the protocol overhead with the aim to make economically feasible and physically realizable the implementation of high overhead-services. In this paper a new header compression scheme for TCP streams, as a specific header compression profile within the ROHC platform, is proposed and analyzed. This new header compression scheme is based on the distinct management of data and acknowledgment streams associated to the TCP stream. To reduce error propagation, a robust encoding technique (W-LSB) and the synergy between three repair mechanisms for damaged compressed packets have been suggested. Thus, headers up to 40-60 bytes can be compressed to 4-6 bytes with great benefits on cost and quality of service (QoS).