Transmission Latency Minimization for Multi-Carrier Broadcast in Clustered Sensor Networks under FBL Regime

In this paper, toward ensuring highly reliable low-latency communication for wireless sensor networks (WSNs) with massive connectivity, we explore the problem of minimizing transmission latency for clustered WSNs, where each clustered WSN is allocated with one carrier for the downlink broadcasting communication. To ensure timely broadcast message delivery, we formulate an optimization problem that jointly allocates blocklengths and transmit power. The low-latency communication demands force us to consider the transmission operating in finite blocklength (FBL) codes. The objective is to minimize the maximum cluster latency, determined by the worst-case node in each cluster, under a total power constraint. To solve the resulting nonconvex problem, we first prove the quasi-convexity of the fractional objective function and then employ Dinkelbach’s transform for an efficient iterative algorithm towards the optimal solution. Numerical results demonstrate that our approach significantly outperforms the benchmark with fixed blocklength and uniform power allocation.