A practical Walsh layering scheme for reliable transmission

Concerning the uncertainty of channels and peak power constraint, we give a new practical layering scheme to do reliable transmission. In our scheme, Walsh matrix is employed to do layer-time coding. Regarding columns of a layer-time coding matrix as layers and rows as time, after Walsh layer-time coding, interference among layers can be removed or diminished by adding rows up. When there are layers decoded successfully after the previous transmission, only not-yet-decoded layers will be retransmitted. Simulation results show that our Walsh layering scheme with hybrid automatic repeat request (HARQ) performs much better than the traditional single-layer ARQ sequential transmission with respect to average time delay.