HARQ Enriched Feedback Design for 5G Technology

It is well recognized in the literature that the performance of the hybrid automatic repeat request (HARQ) transmission can be improved by adapting the transmission parameters through exploiting extra information from the receiver over the feedback channel. This introduces new degrees of freedom for a more flexible per-link optimized transmission. This paper proposes a framework considering the practical aspects of such feedback design and analyzes better resource utilization by retransmission techniques in the 5th generation mobile networks (5G) technology. We propose to generate a decoder state information (DSI) feedback at the receiver side and to enable using this information at the encoder side where retransmission parameters will be set to meet an optimal target block error rate. The savings in retransmission resources can then be utilized for transmission of other packets. The systemlevel simulation results show the attractive enhancement of ~8% average throughput gain by using only one extra feedback bit per HARQ process compared to conventional HARQ approach.