Reseach On Energy-efficient Radio Resource Allocation Algorithm In Multi-cell LTE Network

With the rapid development of wireless mobile communication, user demand for more and more high-speed data service. LTE networks, on one hand guarantes a good user experience for various mobile applications such as video, game, multimedia social networking, on the other hand brings great energy issues, which not only result in high operating costs, but also bring social concern of environmental deterioration. This paper mainly focuses on energy-efficiency of wireless resource allocation algorithm in multi-cell LTE system and conduct in-depth research. In detail, related signaling and standard interfaces of LTE resource allocation is introduced first. It is established that resource allocation is in a distributed mode, and result can be exchanged via a inter-cell X2 interface. Secondly, in order to establish a mathematical model suitable for analysis, a hypothesis is given that the time and frequency domain resources is invariance in the minimum resource unit. The measurement informaion which seriously affect resources allocation is also introduced. This article describes the current status of research LTE radio resource allocation algorithm, especially energy-efficient resource allocation algorithm in multi-cell scenarios.Based on the above analysis, this paper establishes a joint subchannel and power allocation model in multi-cell LTE network on the purpose of maximizing the energy efficiency of the system, while guaranteeing minimum user rate. The model belongs to mixed integer programming problem in optimization theory, and is divided into two sub-problem. They are sub-channel allocation problem under fixed power and power control problem under fixed subchannel allocation.About the subchannel allocation problem under fixed power, a subchannel allocation algorithm and two subchannel adaption algorithms are designed. SGISA algorithm is based on classic max C/I algorithm and optimized by sorting, adding a mechanism to guarantee minimum user rate. Three basic adaption model named removal, exchange and substitute are defined. ESA-1 and ESA-2 algorithms are based on them. Simulation results demonstrate that the allocation algorithm designed in this paper can achieve 95% optimal energy efficiency. It is also verified that the excellent performance is stable in different minimum user rate scenarios and different the number of users scenarios.About network power control problem under fixed subchannel allocation in multi-cell LTE network, we propose a complete information static non-cooperative game model about power control based on interference coordination technique, and prove that the game model exist the Nash equilibrium point. Sharing power control information in X2 interface between e NodeBs, an iterative heuristic algorithm-MICPC algorithm is designed to search for the Nash equilibrium point of above game model. Simulation results show that MICPC algorithm could converge to the Nash equilibrium point, and verify the advantage of multi-cell algorithm using interference coordination techniques than a single-cell algorithm. Such advantage is better in stronger interference environment.Based on the above research on subchannel allocation and power control technology, MEERA algorithm is proposed for resource allocation under QoS constraint with the objective of maximizing system energy-efficiency in multi-cell LTE system. In each stage of MEERA algorithm, resource allocator further optimize the system energy-efficiency on the achieved level. Simulation results show good convergence of MEERA algorithm, and demonstrate that the performance of MEERA algorithm is more energy-efficient and result in most throughput. The performance is better in stronger interference.