QoS Based Resource Allocation for OFDM-Based Cognitive Radio Systems with Mixed Services

In this paper, a quality of service (QoS) based resource allocation for orthogonal frequency division multiplexing (OFDM)-based Cognitive Radio (CR) System with mixed services is proposed. We consider the resource allocation problem for downlink with unoccupied frequency sensed by CR users (CRUs) and total transmission power constraint of the CR base station. In mixed services CR system, the objective of the resource allocation is to ensure the QoS of real time (RT) service and improve the overall performance. We formulate the QoS based resource allocation problem which consists of both queue aware and channel aware scheduling as an optimization solution. A suboptimal with low complexity approach is suggested for practical system. Simulation results show that the proposed resource allocation algorithm performs better than existing algorithms.