Contention-Based Radio Resource Management for URLLC-Oriented D2D Communications

Device-to-device (D2D) communications are becoming a promising technology to support ultra-reliable low-latency communications (URLLC). This paper incorporates contention-based access scheme into radio resource management (RRM), which can not only deal with the sporadic packet arrivals for URLLC-oriented D2D communications, but also avoid wasting time on sending requests and waiting for feedback. However, it cannot be ignored that the collisions may occur to yield transmission failure, especially when two or more users access the same resource block (RB). Thus, we should pay more attention to optimizing users’ RB selection to foster strengths and offset weaknesses of introducing contention-based access scheme, and thereby improve the transmission reliability within the latency budget. Specifically, we formulate the contention-based RRM as an optimization problem which aims to maximize the sum successful transmission probability (STP) of all D2D pairs under the strict latency constraint. Due to its intractability, this optimization problem is transformed into a mixed strategy non-cooperative game, which is proved to be an exact potential game with the sum STP as its potential function. Accordingly, the existence of pure strategy Nash equilibrium (NE) can be guaranteed, and importantly, the optimal integral solution to the optimization problem constitutes a pure strategy NE of the game. Moreover, we propose a distributed RB selection algorithm based on sequential spatial adaptive play (S-SAP), which can converge to the optimal pure strategy NE of the proposed game. The numerical results verify the convergence and optimality of the proposed algorithm.