The fifth-generation (5G) of mobile standards is expected to provide ultra-reliability and low-latency communications (URLLC) for various applications and services, such as online gaming, wireless industrial control, augmented reality, and self driving cars. Meeting the contradictory requirements of URLLC, i.e., ultra-reliability and low-latency, is considered to be very challenging, especially in bandwidth-limited scenarios. Most communication strategies rely on hybrid automatic repeat request (HARQ) to improve reliability at the expense of increased packet latency due to the retransmission of failing packets. To guarantee high-reliability and very low latency simultaneously, we enhance HARQ retransmission mechanism to achieve reliability with guaranteed packet level latency and in-time delivery. The proposed non-orthogonal HARQ (N-HARQ) utilizes non-orthogonal sharing of time slots for conducting retransmission. The reliability and delay analysis of the proposed N-HARQ in the finite block length (FBL) regime shows very high performance gain in packet delivery delay over conventional HARQ in both additive white Gaussian noise (AWGN) and Rayleigh fading channels. We also propose an optimization framework to further enhance the performance of N-HARQ for single and multiple retransmission cases.
翻译:第五代(5G)移动标准预计将为各种应用和服务,例如在线赌博、无线工业控制、无线工业控制、增强现实和自我驾驶汽车提供超可靠性和低延迟通信(URLLC),满足URLLC相互矛盾的要求,即超可靠性和低延迟的要求,被认为是非常具有挑战性,特别是在带宽有限的情况下。大多数通信战略都依靠混合自动重复请求(HARQ)来提高可靠性,而牺牲因故障包的再传送而增加的包装延缓。为了同时保证高可靠性和非常低的延缓度,我们加强了HARQ再传输机制,以在保证的包装延缓度和及时交付的情况下实现可靠性。拟议的非横向共享HARQ(N-HARQ)利用非横向共享的时间间隔进行再传送。在限制区长度(FBL)制度中对拟议的N-HARQ(FBL)制度进行可靠性和延迟分析表明,在常规HARQ交付延迟和非常高的交付率上,在常规的NHARQ(RA-ARE)升级的单一升级框架内,也加强SAR-ARC的升级的自动交付。