Perception And Cognitive Family Base Station Polarization Domain Spectrum Resource Management Research

To meet the data traffic demand increasing at an exponential rate, cognitive femtocell network (CFN) holds significant promise to enhance the overall throughput and indoor coverage in two-tier cellular networks. It enables low-cost consumer-installed femtocell access points (FAPs) with self-organizing framework to opportunistically access the unoccupied spectrum of macro cellular network (MCN). Polarization spectrum sharing offers the coexistence of the two tiers a novel way to improve the spectrum utilization, which is a promising solution to the dilemma of frequency scarcity and the growing demands on spectrum.The dissertation is focused on the polarization spectrum sharing and the crucial issues of polarization spectrum sensing and resource management considering cross-tier and co-tier interference. It is in part supported by the "863" Program, National Science Foundation of China, and the fund from China Scholarship Council.The dissertation is organized as following. Chapter2surveys the existed research on spectrum sharing in the two-tier cellular networks and investigates the polarization spectrum sharing scheme in Chapter3. Chapter4discusses the polarization spectrum sensing based on vector signal processing. Chapter5and Chapter6study the spectrum resource management based on statistical interference analysis and resource partitioning, respectively. The main contents and contributions of this dissertation are issued as follows:1) For spectrum sharing in the two-tier cellular networks, the opportunistic co-channel spectrum sharing between the two tiers is mainly summarized based on the spectrum sensing and management with cognitive radio and femtocell, respectively. The advantages and incoming challenges of the CFN are also investigated.2) To enable effective coexistence of the two tiers, the polarization spectrum sharing is designed based on polarization matching and mismatching with the crucial issues of polarization spectrum sensing and resource management.3) In polarization vector spectrum sensing, we propose a virtual polarization detection method based on a constructed depolarization model for wireless channel to identify the MCN polarization. This method maximizes the received signal to noise ratio and searches the MCN polarization by virtual polarization adaptation, which can significantly improve the sensing performance.4) To reduce the complexity of the virtual polarization adaption, we propose a rapid polarization adaptation based spectrum sensing algorithm for the CFN. It can transfer the two-degree-of-freedom search issue to K single-dimensional issues. Furthermore, the theoretical boundary of the proposed algorithm is derived. The simulation results show that the proposed algorithm converges fast, obtains a high accuracy on MCN polarization identification, and enhances the detection performance.5) To mitigate cross-tier and co-tier interference, we exploit statistical interference models for distributed resource allocation in the CFN. The proposed resource allocation scheme analyzes aggregated interference and estimates the optimization parameters by spectrum sensing, and obtains the optimized channel allocation and power control by each CFN link distributedly. The scheme can converge fast and protect the MCN with litter cost of the CFN performance.6) To enhance the MCN cell-edge performance, a two-level resource partitioning scheme of tier-level and link-level coordination is proposed with femto free zone and data rate reduction factor. Moreover, we design an indicator information bitmap for resource partitioning to reduce the overhead of information exchange. The simulation results show that the scheme can offer a tradeoff between the two tiers.