Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Power allocation, bit loading and sub-carrier bandwidth sizing for OFDM-based cognitive radio | Thumar et al. EURASIP Journal on Wireless Communications and Networking 2011 2011 87 EURASIP Journal on . http content 20ii i 87 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Power allocation bit loading and sub-carrier bandwidth sizing for OFDM-based cognitive radio 1 1 12 1 Vinay Thumar Taskeen Nadkar Tej Gopavajhula Uday B Desai and Shabbir N Merchant Abstract The function of the Radio Resource Management module of a Cognitive Radio CR system is to evaluate the available resources and assign them to meet the Quality of Service QoS objectives of the Secondary User SU within some constraints on factors which limit the performance of the Primary User PU . While interference mitigation to the PU spectral band from the SU s transmission has received a lot of attention in recent literature the novelty of our work is in considering a more realistic and effective approach of dividing the PU into sub-bands and ensuring that the interference to each of them is below a specified threshold. With this objective and within a power budget we execute the tasks of power allocation bit loading and sizing the sub-carrier bandwidth for an orthogonal frequency division multiplexing OFDM -based SU. After extensively analyzing the solution form of the optimization problems posed for the resource allocation we suggest iterative algorithms to meet the aforementioned objectives. The algorithm for sub-carrier bandwidth sizing is novel and not previously presented in literature. A multiple SU scenario is also considered which entails assigning sub-carriers to the users besides the resource allocation. Simulation results are provided for both single and multi-user cases which indicate the effectiveness of the proposed algorithms in a CR environment. Keywords cognitive radio OFDM interference mitigation power allocation bit loading sub-carrier bandwidth sizing I. Introduction A new paradigm called Cognitive Radio CR has emerged in
