QoS-aware scheduling with optimization of base-station power allocation in downlink cooperative OFDMA systems

Abstract

We investigate the quality of service (QoS)-aware scheduling problem for downlink cooperative orthogonal frequency division multiple access systems. Our work mainly focuses on the optimization problem for joint base-station power allocation, relay selection and subcarrier assignment with QoS guarantees. We first demonstrate that by introducing the binary assignment variables, the QoS-aware joint scheduling problem can be formulated as a mixed binary integer nonlinear programming (MBINP), which is computationally intractable. In order to solve this MBINP, power and QoS prices are introduced to transform the intractable MBINP into its corresponding dual problem via its Lagrangian, and then a two-level dual decomposition method is proposed to solve it. We derive the algorithm with the deployment of amplify-and-forward (AF) relays and/or decode-and-forward (DF) relays, analyze its computational complexity and suggest some generalizations. Finally, simulations demonstrate that our proposed method outperforms some previous works in terms of spectrum efficiency and QoS satisfaction. © 2013 Stolojescu-Crisan and Isar; licensee Springer.