Polynomial-Complexity Optimal Resource Allocation Framework for Uplink SC-FDMA Systems

In this paper, we study a weighted-sum rate maximization problem in SC-FDMA which is adopted as the multiple access scheme for the uplink in the 3GPP-LTE standard. Unlike OFDMA, in addition to the restriction of allocating a sub-channel to one user at most, the multiple sub-channels allocated to a user in SC-FDMA should be consecutive as well. This renders the resource allocation problem prohibitively difficult and the standard optimization tools (e.g., Lagrange dual approach widely used for OFDMA, etc.) can not help towards its optimal solution. We propose a novel polynomial-complexity optimization framework that is inspired from the recently developed canonical duality theory. We first formulate the resource allocation problem as a binary-integer programming (BIP) problem and then transform the BIP problem into a continuous space canonical dual problem which is a concave maximization problem. Based on the solution of the continuous space dual problem, we propose a resource allocation algorithm that has polynomial complexity. We provide conditions under which the proposed algorithm is optimal. We compare the proposed algorithm with the existing algorithms in the literature to assess its performance. Simulation results show that the proposed algorithm improves the system performance significantly.