The Spectrum Allocation In Cognitive Mobile Communication System Based On Spectrum Holes Classification

With the development of wireless communication technology and socio-economic, spectrum resource is an indispensable precious resource for wireless communication in modern society, especially mobile communications system. However, because of the existing fixed spectrum allocation policy constraints, the frequency utilization of many licensed spectrum is relatively low, making frequency resources much tenser. In order to improve the frequency utilization of licensed spectrum, cognitive radio technology is proposed.Hidden terminal and exposed terminal problem is one of the most challenging issues of cognitive radio spectrum sensing and spectrum allocation, which will make a direct impact on the performance of cognitive radio. In this paper, hidden terminal and exposed terminal problem and the mutual interference between primary and secondary systems are analyzed. According to the different requirements of the available frequencies for secondary transmitters and receivers, the spectrum holes have been classified to transmit spectrum holes and receive spectrum holes. Further the differences of transmit/receive spectrum hole sensing are analyzed, as well as the impact to different duplex systems caused by spectrum hole classification.Additionally, based on the spectrum holes classification, a novel spectrum allocation scheme in cognitive mobile communication system has been investigated. In this scheme the spectrum allocation for inter-cell and intra-cell is analysized detailed, as well as the spectrum hole concession and re-examination, to ensure the spectrum collision beween primary systems and secondary systems will not happen.Finally, the performance of spectrum allocation scheme proposed in this paper based on spectrum holes classification is validated by the mathematical proof and system level simulation platform. Firstly, the ability to solve hidden terminal and exposed terminal problem of the proposed scheme is verified by mathematical proof. secondly, system level simulation platform is designed for the proposed scheme and the comparison scheme based on traditional transmitter sensing, and the pectrum sensing result, throughput of secondary system, unexpected rate and falsed rate of spectrum sensing are exported. The simulation results show that the proposed spectrum allocation scheme has significant performance gains in the spectrum detection accuracy and throughput of secondary systems.