Research On Load Balancing And Energy-saving Technology Of Heterogeneous Cellular Networks

With the wide application of 4G communications technology and rapid increase of mobile users, wireless communication systems have built up heterogeneous cellular networks combined with small cells and macro cells due to the growing increase of multimedia service requirements. The application of small cells has increased the network capacity. However, dynamic change of mobile users in small cells has caused an imbalanced distribution of traffic load in time and space and the decline of the resource utilization efficiency. Moreover, the massive deployment of small cells brings about growth of energy consumption. Thus, load balancing and energy saving in heterogeneous networks have become a research topic.Based on the distributed base station structure in LTE systems, an improved spectrum allocation approach in combination with frequency multiplexing and graph theory is proposed. In this approach, certain numbers of sub channels can be allocated properly to small cells, combined with the shifts of services demand in specified cells and following the principle that adjacent small cells utilize orthogonal sub channels to avoid co-channel interference. Furthermore, it can be optimized according to resource allocation in adjacent cells so as to acquire more sub channels for reuse and higher resources utilization efficiency, thus enhancing network performance.Sleep mode of small cells under the heterogeneous environment is investigated to save energy, and a sleep mode scheme with bandwidth aided by macro cells is put forward. When the total loads become light, users in small cells with low load can move to macro cells, and these small cells can turn into the sleep state. When the total loads become heavy, aided bandwidth of macro cells will be allocated to users whose services requirements cannot be met in order to improve users’ satisfaction efficiency in these small cells. Experimental results show that the proposed scheme has certain advantages, system throughput along with satisfaction of small cells is enhanced, and some energy of small cells can be saved in different network schemes.