Ultra-Reliable and Low Latency Wireless Communications with Burst Traffics: A Large Deviation Method

Ultra-reliable and low latency communications (URLLC) has recently attracted much attention because it holds the promise of supporting mission-critical applications in task-driven radio access networks. In URLLC, finite-blocklength coding plays an important role. In this paper, we are interested in the performance limit of finite-blocklength coded wireless URLLC with burst traffics, which may induce severe delay in practice. A large deviation technique is exploited to derive the delay violation probability given a hard delay constraint. Specifi-cally, an approximate QoS exponent is conceived to characterize the reliability-latency tradeoff, i.e., tradeoff between the error probability and delay violation probability. Further, we present closed-form upper and lower bounds of the QoS exponent, which are shown to become tight in the high signal-to-noise ratio (SNR) regime. Our theoretical analysis is also validated by numerical results.