Research On Channel Aggregation Strategy In Cognitive Radio Network

The surge in demand for wireless communication services leads to a serious spectrumresource scarcity than before. By eliminating the "white hole" in spectrum, cognitive radionetworks can achieve efficient utility of spectrum resources. In this thesis, we carry outstrategy investigation, performance analysis and system optimization for channelaggregation in dynamic spectrum allocation strategy with centralized cognitive radionetworks.Firstly, in order to reduce the transmission delay of data packets and improve theutilization of spectrum resources, a channel aggregation strategy for primary users (CAS-P)is proposed. Taking into account the higher priority of primary users, several channels areaggregated for the transmission of a primary user packet, while a secondary user packetopportunistically accesses one idle channel of the aggregated spectrum for datatransmission.Secondly, in order to ensure the transmision for the secondary user packets that arealready admitted by the system, a retrial buffer is set for the interrupted secondary userpackets. Based on CAS-P strategy, a channel aggregation strategy with retrial buffer(CAS-RB) is proposed.Thirdly, for CAS-P strategy, a discrete-time multi-server priority queueing modelwith synchronization interruption is established. By using matrix geometric solutionmethod, the system performance measures are derived. A discrete-time synchronizationinterruption multi-server priority queuing model with retrial buffer is built for CAS-RBstrategy, then the state transfer process is studied. By using Gauss-Seidel iterativealgorithm the system performance measures are resolved. Numerical experiments andsimulation experiments are also conducted to quantitatively evaluate the systemperformance of CAS-P strategy and CAS-RB strategy.Finally, based on the trade-off between the system performance, cost functions areconstructed to optimize the system performance of CAS-P strategy and CAS-RB strategy.For CAS-P strategy, the individal benefit and social welfare are analyzed, then a pricing scheme for CAS-P strategy is provided to achieve the social optimization.