A robust type II hybrid ARQ scheme with code combining for mobile communications

A type II hybrid ARQ (automatic repeat request) scheme, using convolutional coding and code combining, is proposed and analyzed for the land mobile communication system. The protocol adopts an adaptive coding scheme for the header which selects the code rate according to the channel conditions. A simple channel estimation technique is used together with a code synchronization procedure. Simulation results have shown that a significant throughput improvement is achieved with the proposed scheme over the conventional type II hybrid ARQ scheme under severe channel conditions