Cross Layer HARQ 2 Cooperation with Throughput Improvement

Cross Layer Hybrid Automatic Repeat reQuest 2 (HARQ 2) Cooperative Diversityis an efficient transmission scheme, proposed in this paper. This cross layer design scheme, between the physical and data link layer, provides BER and throughput improvements over traditional Coded Cooperation due to the fact that in some cases the base station has already decoded a particular set of information bits using a user´s initially transmitted parity and not all parity bits are required. The user however is not informed by the base station of this, during Coded Cooperation. With the proposed cross layer design users can then transmit incremental parity packets and await feedback from the base station to decide whether further parity is required for a particular set of information bits. Improvements in Bit Error Rate (BER) and throughput are observed by the cross layer design over Coded Cooperation. BER theoretical bound analysis is performed and is validated by simulations in a block fading channel. Throughput results are also presented.