Full packet headers consume valuable bitrate, which is especially costly in satellite links and some terrestrial wireless links. This has motivated the compression of packet headers by exploiting their correlation via using finite-state machines. The drawback is that compression in the presence of channel errors (packet loss) may result in error propagation. We offer several designs by adapting error control codes for the requirements of packet header compression in uni-directional and bi-directional links, and explore the tradeoffs in complexity, delay, and system performance. For the bi-directional link, we propose a new design called predictive hybrid ARQ and evaluate its performance. Experiments show significant gains in link-layer throughput as well as improved application layer performance demonstrated via video transfer experiments.

This paper proposes a system using convolutional codes to mitigate error propagation in packet header compression. Convolutional codes are a class of forward error correction (FEC) codes, and their use is motivated because on uni-directional links loss of even one packet can render subsequent packets useless. A combination of two interleavers is used to address channel memory and increase the power of the code, and the optimum yet computationally efficient Viterbi algorithm is used for decoding at the receiver. Simulation results demonstrate the advantages of the proposed scheme.

Header compression saves bandwidth, but it also introduces error propagation whenever packets are lost. We propose to use error correcting codes on the compressed packet headers. The result is an overall system that maintains most of the bandwidth savings of header compression and yet is robust with respect to errors. The key to achieving this tradeoff is appropriate distribution of parity symbols across the packets. The proposed system performs better than ordinary header compression and as well as the TWICE algorithm. In most cases, the effects of the error propagation can be almost removed, such that the end-to-end packet loss rate is similar to a system with no header compression, while the bitrate savings are largely maintained.