Resource Allocation for QoS-Aware OFDMA Cellular Networks with Cooperative Relaying

This paper proposes a QoS-aware resource allocation scheme, called as cooperative resource allocation scheme (CoRA), for relay-based OFDMA systems with both QoS and Best-effort (BE) users. Using CoRA, cooperative transmission between the Base-station (BS) and the Relay-station (RS) is employed to fulfill the requirements of QoS users. Moreover, resource scheduling is allowed not only at the BS but also at each RS to fully exploit time-varying channel state and multiuser diversity, so as to achieve efficient radio resource utilization. The design of subchannel and power allocation in CoRA can be formulated as a non-linear combinatorial optimization problem, which aims at maximizing the system utility while satisfying the data rate requirements of QoS users and the separate transmission power constraints at both BS and RSs. To address the prohibitively high computational complexity in solving the optimization problem, we decompose the global optimization problem in CoRA into subchannel allocation and power control sub-problems as a suboptimal solution. Numerical results demonstrate that our proposed CoRA scheme is able to significantly improve the network performance in terms of power saving, user utilities, system throughput, as well as the number of admitted users. Key-Words: Cooperative transmission, Subchannel allocation, Power control, Quality-of-service