Research Of Area Spectrial Efficiency And Area Energy Efficiency In Ultra-Dense Networks

With the development of science and technology in the progressive times, the digital information communication has raised the work efficiency and made people’s life and production unprecedentedly convenient. As we look ahead, faster transmission rate, access rate and mobility will be required because of our increasing demand for information. And we will ask for higher densities of network, link as well as flux on the purpose of further control over everything. Moreover, the brand new communication technology will be needed to support the user experience. In contrast to the existing 4G technology, the 5G is a more powerful mobile communication technology with higher transmission rate, lower transmission delay and more improved security mechanism as well as better user experience. To achieve these performances, a mass number of wireless transceiver nodes are essential to be arranged in scenes with different environments. These nodes such as Macro evolved Node B(e NB), Micro e NB, Home e NB and relay stations will form a network with high intensity, namely, the Ultra-Dense Networks(UDN) in 5G.Based on the hierarchical heterogeneous networks, UDN significantly enhances the system capacity by arranging small-sized networks with high density and low power consumption, which is a method to effectively shorten the distance between the transmitter and the receiver, to increase the spectrum effectiveness, and to promote the overall performance of the network by shunting the flux. Compared with the single-layer homogeneous network, the hierarchical heterogeneous network runs with more flexible network deployment, higher information rate and larger system capacity. In terms of UDN, Area Spectrum Efficiency(ASE) is introduced to replace the traditional one which cannot well represent the system performance as there are many communication nodes in each single area where the throughput is huge.ASE is an important index to measure the performance of UDN. As the overlap in a network, analyses on ASE are complex because there are rather strong interferences of same frequency between layers or cells in the same layer. Meanwhile, different network topologies also have influences on the analyses of ASE. Aiming at two existing typical network topologies, the thesis is about modeling corresponding solutions to ASE by analyses on same frequency, same layer and cross layer interferences. Besides, effects on ASE caused by multiplex ratio of spectrums, numbers of users in the system and transmitting power of the base stations are analyzed as well as the uplink and downlink respectively.Area Energy Efficiency(AEE) is another vital index to evaluate the performance. As the communication industry is the most basic and widest service industry in the social life, mass arrangements of intensive networks have resulted in huge energy consumption, and the waste of energy has also caused by plenty of interferences between networks. Consequently, it is quite essential to effectively decrease these interferences and save the energy consumption of the networks. In the thesis, the system performance is analyzed on bases of both physical and network layers. On the one hand, the beam forming technology in the physical layer optimizes the system energy efficiency by effective arrangements on the interferences. On the other hand, the joint transmission of the base stations in the network layer further enhances the system energy efficiency.