Energy-Saving Management Mechanism For Wireless Communication Networks

Energy consumption of ICT (Information and Communication Technology) has become an important factor that affects global warming.80%of ICT energy is consumed during the operation procedure, so how to reduce the power consumption for communication equipments during operation and maintenance stage has drawn widespread concentration. As a major part of ICT industry, energy costs of wireless communication networks are growing year by year as well. And high efficient design and research for these networks turn into a hotspot. Currently quantities of access points exist in wireless communication networks, and these points consume about60%energy of the entire network. Reducing energy costs for these points take on much significance for green ICT. In fact, capacity of current wireless communication networks is designed according to peak traffic. During midnight, traffic of Base Stations (BS) is fairly low, and much resource and energy are wasted. Therefore, a mainstream method to saving energy in wireless communication networks is switching off several BS through network management when network traffic is low. Saving energy requiring frequent operation for BS, so traditional network management for wireless communication networks which need much manual configuration and control may not be suitable. Consequently,3GPP propose ESM (Energy-Saving Management) in Self-Organizing Networks (SON) to implement saving energy for wireless communication networks.When traffic of wireless communication networks is low, ESM concentrates on how to signal several BSs to sleep, and control remain active BSs to compensate regional coverage and capacity. Key issues of ESM include energy-saving trigger and recovery strategies, energy components of wireless communication networks, and specific energy-saving method. Current research still exist some deficiencies. For energy-saving trigger and recovery strategies, traffic of BS is considered as a basic condition. Though traffic prediction methods are profiling from practical data variation, their offsets may affect accuracy for energy-saving method. Still, effect of buffer time is always ignored. For the energy components, relationship among wireless parameters and BS energy lack systemic exploration. Moreover, correlation among service, coverage, capacity and dynamic part of BS power still lack accurate quantification. For specific energy-saving method, on the one hand, coverage compensation scheme taking dynamic traffic into consideration under irregular topology is deficient; on the other hand, model and analysis for energy-saving related wireless parameters is scanty as well. Meanwhile, performance effect caused by energy-saving methods should be evaluated too.Based on above problems, we propose corresponding integrated ESM mechanisms for four different scenarios. Each mechanism gives in-depth research on self-organized ESM framework, energy-saving trigger and recovery conditions, energy consumption model of wireless communication networks, and specific energy-saving method. Specifically, contributions of this paper are shown followed:(1) For homogeneous network scenarios with uniform traffic distribution (suitable for3G and LTE/LTE-A), we propose a novel centralized self-organized energy-saving mechanism based on coverage definition signal power adjustment. The mechanism gives the functional model and procedures for self-organized saving energy firstly. Then it analyzes energy-saving trigger and recovery conditions, and explores energy consumption model based on coverage definition signal power. For coverage compensation, local method is Trigonal Pair (TP). Based on TP, regional BS state determination method is introduced next. Then, for BSs under compensation state, we construct mathematical model and adopt modified Simulated Annealing (SA) to compute adjustment of coverage definition signal powers for them. Performance evaluation methods are discussed as well. Simulations and discussions for this mechanism are shown at last.(2) For homogeneous network scenarios with asymmetric traffic distribution, hybrid service from CS and PS domain, and without the ability of remote antenna adjustment (mainly suitable for3G, compatible of LTE/LTE-A), we propose a novel centralized self-organized energy-saving mechanism based on traffic channel signal power adjustment. Still, self-organized ESM function and procedure is given firstly. Then corresponding energy-saving trigger and recovery conditions, and energy consumption model based on traffic channel signal power are proposed. Local compensation method is OP (Opposite Pair), and regional BS states determination method based on OP is introduced then. For BSs under compensation state, we construct mathematical model whose optimized variables are matrix for traffic channel signal power. Immune optimization algorithm which is suitable for multiple parameters is adopted then to compute adjustments of these signal powers. Simulations and discussions are given at last as well.(3) For homogeneous network scenarios with asymmetric traffic distribution, hybrid service from CS and PS domain, and ability of remote antenna adjustment (suitable for3G, and LTE/LTE-A), we propose a novel centralized self-organized energy-saving mechanism based on multiple parameters adjustment. We introduce corresponding ESM function and procedure, energy-saving trigger and recovery conditions, and energy consumption model firstly. Local and regional coverage compensation methods are based on modified TP. For BS under compensation methods, mathematical model is constructed which takes antenna tilt vector and traffic channel power signal as optimized variables. A high efficient particle swarm algorithm is adopted to resolve the problem. At last we give the simulation and discussion.(4) For heterogeneous network scenarios with asymmetric traffic, interface between BSs, and multiple kinds of BSs/cell (such as LTE/LTE-A), we propose a novel distributed ESM mechanism based on geometrical topology. We introduce distributed self-organized functions and procedures firstly. Then aiming at distributed management environment, we research the trigger and recovery conditions, energy consumption model, local compensation method for heterogeneous networks, grading ES execution and recovery algorithm, and performance evaluation method. For above issues, the trigger and recovery conditions are extended to multiple stages. And we analyze the optimal compensation radius for OP and TP from geometrical topology perspective. Still, we reduce the dimension of ES algorithm to linear complexity. For performance evaluation, we discuss the spatial interference distribution, service rate distribution, and so on. We evaluate the energy efficient, coverage and such performance for our mechanism under irregular topology regions under simulation scenario.Based on regional traffic variations, we propose four integrated ESM mechanism under four different network scenarios. In each machnism, we give corresponding analysis and research for key issues of self-organized ESM. The feasibility and validity of these mechanisms are evaluated through simulations. Results show that these mechanisms take on practical significance.