Performance enhancement of ROHC U-Mode in wireless links

Robust Header Compression (ROHC) is a standardized option defined by the IETF to compress the various transport and communication protocol headers over wireless links. In the present day scenario, when the applications and services are evolving to become more bandwidth hungry, wireless networks are expected to be capable of letting them drive on wireless links and provide required quality of service (QoS). For wireless networks with high bit error rate (BER), it is always a challenge to achieve desired QoS by maximizing true bandwidth utilization. ROHC is an efficient mechanism for effective use of bandwidth. The framework compresses the header size of the protocols, based on redundant information being carried, thereby intelligently using the available bandwidth without drop in QoS. This paper studies and implements the existing ROHC standard and various optimization parameters involved, to finally propose a Modified ROHC Implementation. The paper proposes to reduce the size of the (second order) SO packet, than that of standard ROHC mechanism, by omitting sending of context identifier (ID) in SO packet in modified ROHC alogarithm, and supplementing this absence of information by inbuilt mechanism of algorithm to generate the identification of SO packet at decompressor end. These two ROHC mechanisms are implemented and compared on the basis of average header length and decompression failures.