Adaptive HARQ for imperfect channel knowledge

We consider a link adaptation scheme with adaptive coding and modulation and adaptive retransmissions on a block fading channel. Therefore, we characterize the performance of the employed channel code with puncturing and repetition coding in a unified way and use this description to devise a method to adapt modulation and code rate in the initial transmission as well as in all retransmissions. We evaluate the performance of two adaptation strategies and compare them to the throughput-optimum and a simple scheme with fixed-length retransmissions.