Adaptive Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems

Most existing work on adaptive allocation of subcarriers and power in multiuser OFDM systems has focused on homogeneous traffic consisting of delay-constrained data (guaranteed service) or delay-tolerant data (best-effort service) only. In this work, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and no-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the DC traffic under a total transmission power constraint. Finding the optimal allocation of subcarriers and power is formulated as a convex programming problem. An iterative algorithm is proposed to compute the optimal solutions numerically. A low-complexity suboptimal allocation algorithm is also presented. Simulation experiments are conducted to evaluate the performance of the proposed algorithms in terms of service outage probability and achievable transmission rate pairs for DC and NDC traffic.