Optimal Power Allocation and Power Constraint in OFDM-Based Cognitive Radio Systems

Optimal power allocation and power constraint in OFDM-Based cognitive radio systems

Cognitive Radio (CR), which aims to improve spectrum utilization by accessing the spectrum originally licensed to a primary system, is a promising concept. In cognitive radio system based on orthogonal frequency division multiplexing (OFDM), the optimized algorithms for sub-carrier power allocation share the problems of complex iterative calculation and difficult realization. In this case, a su...

X Power Allocation in OFDM-Based Cognitive Radio Systems

Power Allocation in OFDM-Based Cognitive Radio Systems

In this thesis, we develop an subcarrier transmission suboptimal power allocation algorithm and an underlay subcarrier transmission optimal power allocation algorithm for the orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems with different statistical interference constraints imposed by different primary users (PUs). Given the fact that the interference constr...

Optimal power allocation in multiuser OFDM systems

Multiuser orthogonal frequency division multiplexing (MU-OFDM) is a promising technique for achieving high downlink capacities in future cellular systems. A key issue in MU-OFDM is the allocation of the OFDM subcarriers and power among users sharing the channel. Previous allocation algorithms cannot ensure fairness in advance. In this paper, a proportional rate adaptive resource allocation meth...

Optimal Subcarrier Power Allocation in OFDM Based Cognitive Radio Networks by Using Gradient Based Methods

The Power allocation in Orthogonal Frequency Division Multiplexing (OFDM)-based cognitive radio networks is designed by gradient based method. The gradient based method in which the power allocated between subcarriers by considering the interference constraint, capacity of CR users and channel gain. Utilize the gradient based descent approach to allocate power to subcarriers in Cognitive Radio ...