Research On Resource Allocation Algorithm For Green Wireless Communication System

The main optimization target of wireless mobile system has changed from maximizing the cell coverage in 2nd-generation to maximizing the channel capacity in 3rd-generation, and now gradually turned to maximizing the energy efficiency in 4th-generation as well as future communication system. Green Radio Communication which mainly focus on energy saving and emission reduction, environmental protection and sustainability is becoming a hot research direction.The resource allocation techniques in green wireless communication system are designed to pursue highest system energy efficiency(EE) as well as resource fairness among users under the premise of meeting the demands of the system spectral efficiency through sub-carrier scheduling, power allocation and even the application of renewable energy. This thesis focuses on energy efficiency and the optimization algorithms in three wireless communication systems.This thesis first takes a brief introduction in frequency division multiplexing(FDM) systems. By summarizing the existing research results and directions of green communication, the content and organization of this thesis is determined.In chapter two, we research on resource allocation in multiuser orthogonal frequency division multiple access(OFDMA) systems. Firstly, we analyze several traditional resource allocation algorithms. Against the energy efficiency fairness among users, we propose an energy-efficient proportional resource allocation algorithm. This algorithm can achieve a substantially proportional fair on EE among users and get a relatively high overall EE under the transmission rates of users.In chapter three, we study the resource allocation in single carrier frequency division multiple access(SC-FDMA) systems. By clustering subcarriers, we keep the single-carrier characteristics of SC-FDMA system. Firstly, we cluster the sub-carriers in same number, assign to users with different methods and analyze the impaction on system EE and fairness on EE among users. Then, discuss the impaction with different receivers and different equivalent channel indicators such as Carrier-to-Noise Ratio on system performance. With the low EE brought by the inflexibility subcarrier clusters allocation, we propose a continuous subcarrier clusters allocation algorithm based on the optimal energy efficiency, which can obtain a high EE under the restriction of system service requirements.In chapter four, we research on the novel resource allocation based on renewable energy. Firstly, we formulate the optimization model of minimizing the transmission time in energy harvesting communication system. For the unpredictable of harvested energy, we discuss a wireless communication system driven by both harvested energy and traditional energy and propose an energy supply algorithm, which ensures the transmission quality and uses the harvested energy as much as possible.Chapter five concludes the thesis and indicates some possible areas for future research.