Reseaech On LTE Green Energy Saving Algorithm And NS-3 Simulation Platform

With the continuous development of wireless communication technology in the last ten years,the number of cell base stations has increased from tens of thousands to millions,which leads more greenhouse gases released.At the same time,we need to spend more resources to maintain the BSs.In addition,the 3G and 4G spectrum are common in the high frequency band,leading much serious transmission loss.In order to ensure the normal communication needs of,the mobile networks operator has to deploy more low power nodes,which further increases the energy consumption of the whole communication system.On the other hand,with the further intensification of global warming and the increasing awareness of Communications Technology Information in environmental protection,the research on green energy saving strategies and the reduction of energy consumption of cellular networks are becoming more and more important.In addition,the mobile Internet business develops rapidly,the proportion of data business in the whole system is growing.And most number of data services are in the interior,which means the traditional cellular network architecture limited by the larger penetration loss and location problems is increasingly difficult to meet need of the growing data business.In order to solve the problem of hot coverage indoor,heterogeneous networks have been proposed as the advantages of high spectrum utilization,flexible deployment,high energy efficiency and so on.Because of the high density of the network,the heterogeneous network will greatly increase the energy consumption of the system,and it is necessary to adopt the appropriate energy saving strategy.However,the direct introduction of energy saving technology in the traditional cellular networks can not achieve the expected energy efficiency in heterogeneous networks.Considering the characteristics of HetNet and the distribution of user's service in time and spatial domain,we proposed an improved hybrid base station sleep algorithm,and its performance is verified by simulation.In addition,a system level simulation platform based on HetNet was builded based on NS-3 by modifying the LTE module.The main work of this paper is summarized as follows:Firstly,the architecture of LTE system is summarized,and the energy saving rate of the system is discussed in detail.The measure index of base station energy saving is summed up and the fit index is chosen according to the model.Alternatively,we introduced the common base station energy saving strategy,and their advantages and limitations are summarized as well.Secondly,we proposed a hybrid base station sleep algorithm for the distribution of traffic volume in the LTE hierarchical cell.The algorithm is composed of two steps.At first step,the global information is obtained by acquiring the global information and the base station is used to enter the sleep state according to the utilization ratio of base station.The second step is to extract the local channel state information from the UE to adjust the transmit power of the base station.From the simulation results,it can be seen that this algorithm can effectively reduce the system energy consumption and rate of break-off under the premise of ensuring the users'QoS.Finally,the LTE hierarchical architecture system level simulation platform is built based on NS-3 software,by implementing the handover within the AS with X2 interface,the handover cross AS with X2 interface and the handover cross X2 without X2 interface.The main work contains modifying the RRC,MME,SGW module and adding the AS and Ccf module.