Adaptive interlaced encoding

We present a novel scheme coined as adaptive interleaved encoding (AIE) that enhances the spectral efficiency of wireless communication systems. In particular, AIE can compensate the spectral efficiency loss due the pilot transmission and the resultant channel estimation errors when the receiver employs for example nearest-neighbour decoding by using the estimated channel gain as it were the true one. AIE is constructed based on multi-coding. At the transmitter for each coherence interval, the scheme interlaces coded symbols of different codewords belonging to variable-rate codebooks. At the receiver, a sequential decoding along with a progressive refinement of the channel estimation using virtual pilot expansion is employed. We investigate ergodic block fading channels, over which the channel gain stays constant during one coherence interval and changes independently over different intervals and show that AIE outperforms the conventional single-rate pilot-assisted transmission.