We consider a cognitive network which is operating with licensed networks simultaneously. One of the major concerns lies in the fact that cognitive networks may cause harmful interference to licensed users. This paper focuses on a joint channel and power allocation scheme that can both protect licensed users and meet the quality of service (QoS) of cognitive radio users with fairness. The problem can be formulated as a nonlinear programming. For reducing complexity in obtaining optimal channel and power allocation scheme, we propose a two-step suboptimal scheme that can achieve good performance with lower complexity. In the first step, resources, such as channels and powers, are allocated by cognitive radio base station (CRBS) based on fairness and QoS requirements to get the maximum available resources of cognitive radio customer premises equipment (CRCPE). In the second step, to get the final resource and reduce algorithm complexity, the allocation task is accomplished by each CRCPE simultaneously, rather than accomplished by CRBS in a serial order. Theoretical analysis and simulation results show that our scheme can support the QoS of CRCPEs with both lower power consumption and fair resource allocation.
['Yueling Che', 'Jie Chen', 'Wanbin Tang', 'Shaoqian Li']
A Two-Step Channel and Power Allocation Scheme in Centralized Cognitive Networks Based on Fairness