Performance of hybrid ARQ techniques based on turbo codes for high-speed packet transmission

Since the asymmetric service is the focus on the future mobile communications, Internet services such as downloads of large data files from Web sites have been gaining popularity. Reliable high-speed (2 Mbps and above) downlink packet transmission becomes a topic of great interest. Hybrid ARQ is one of such techniques which can be used to provide reliable packet transmission. In this paper, different hybrid ARQ techniques, namely Type III multiple redundancy, Type II incremental redundancy, Type I with and without packet combining and Type I with soft information (SI) based on turbo codes are compared. Comparisons between turbo codes and convolutional codes for each hybrid ARQ technique are also investigated. Moreover, the complexity of different hybrid ARQ technique is evaluated afterwards. The results show that Type II incremental redundancy hybrid ARQ technique based on turbo codes gives the best throughput performance at the cost of larger memory requirement. It is more suitable for future high-speed packet transmission where the memory requirement is not so crucial. Type III multiple redundancy based on turbo codes achieves the second best throughput performance with each transmission self-decodable. It is more suitable for certain applications such as deep space communications. Type I with packet combining technique achieves the relatively better throughput performance with less memory requirement. It is more suitable for applications where memory is the most crucial.