Scheduling in Centralized Cognitive Radio Networks for Energy Efficiency
With growing concern on environmental issues and emerging green communications paradigm, Cognitive Radio (CR) networks have to be considered from energy efficiency perspective. In this paper, the authors focus on scheduling in CR Networks (CRNs) in which Cognitive Base Station (CBS) makes frequency allocations to the CRs at the beginning of each frame. A cognitive scheduler must consider the diversity among CRs' queues and channel capacities in terms of number of bits as well as the channel switching cost from one frequency to another. Taking all these into account, they formulate the scheduling problem as energy efficiency maximization problem which is a Non-Linear integer Programming (NLP) problem and thereby hard to solve.