Generalized type II hybrid ARQ scheme using punctured convolutional coding

In this paper, we present a method to construct rate-compatible convolutional (RCC) codes from known high-rate punctured convolutional codes, obtained from best-rate 1/2 codes. The construction method is rather simple and straightforward, and still yields good codes. Moreover, low rate codes can be obtained without any limit on the lowest achievable code rate. Based on the RCC codes, a generalized type I1 hybrid ARQ scheme, which combines the benefits of the modified type I1 hybrid ARQ strategy of Hagenauer with the code-combining ARQ strategy of Chase, is proposed and analyzed. With the proposed generalized type 11 hybrid ARQ strategy, the throughput increases as the starting coding rate increases, and as the channel degrades, it tends to merge with the throughput of rate 1/2 type I1 hybrid ARQ scheme with code combining, thus allowing the system to be flexible and adaptive to channel conditions, even under wide noise variations and severe degradations .