Non-orthogonal HARQ for Delay Sensitive Applications
Faisal Nadeem, Mahyar Shirvanimoghaddam, Yonghui Li, Branka S. Vucetic · 2020
In this paper, a non-orthogonal hybrid automatic re-peat request (N-HARQ) packet transmission strategy is proposed for ultra-reliable delay sensitive communications. As opposed to conventional HARQ, where retransmission of the failing packet is provided in new time slots, in the proposed scheme, retransmission of the packet is served together with the next arriving packet. Using N-HARQ, we avoid the queuing delay due to retransmission and reduce the packet arrival delay. We consider the short block length regime and analyze the error rate, throughput and delay performance of N-HARQ using the Markov model. Simulation results show that the proposed scheme achieves superior performance in providing packet arrival delay guarantee in comparison to its baseline orthogonal HARQ (O-HARQ).