Research On Communication Performance Improvement In Multi-cell Systems Based On Intefrerence Alignment

With the rapid development of wireless communication technology, people’srequirements of the quality and speed of the wireless communication increase continually.Coupled with the accessing of the Internet to the wireless network, the demand of thewireless communication performance is more and more harsh. The more demands, themore questions. Because the wireless channel is open, superposition and broadcasting, theissues between limited spectrum resources and interference of multi-user wirelesscommunication system can not be ignored.Interference Alignment technology probably plays an important role in the multi-cellwireless mobile communications system. In a traditional multi-input multi-output(MIMO)wireless system, due to some factors, like the more demands for the performance, thereducing of the square of the cell area, the increasing number of the base station and so on,users at cell edge(UEs) may suffer serious inter-cell interference(ICI) from adjacent cells.Interference Alignment technology can cancel the interference without affecting thecommunication quality of the primary user to improve the system performance and thequality of the communication service.Precoding technology, as the core technology of Interference Alignment, attractsscholars’ deep research over the years. In this paper we establish a multi-cellcommunication system model with seven cells (in each cell five active users are allocated)to simulate the real communication situation among the cells. Precoding scheme under theSLNR (signal-to-leakage-and-noise) algorithm combines with interference coordinationunder the cooperative communication to research joint precoding among multi-cell basestations. Compared the simulation result with classical ZF and SVD precoding algorithm,and gave the analysis on the throughout under the three algorithms and the cumulativedistribution function(CDF) of the throughout and the SINR. The conclusion is that the jointprecoding under SLNR greatly improved the system performance.On the other hand, designing to use appropriate transmission technology in themultiple-input multiple-output (MIMO) systems can make it obtain large spectrumefficiency. But in the actual application process, designing multi-antenna at the transmitterand receiver of the MIMO system has its limitation of computational complexity. Besides,with the increase in the number of antennas and the base stations, antenna RF link andpower amplifying link have been increased. It is a big hardware cost. From the viewpointof saving resource and power, solving the redundant of overhead hardware is verynecessary. Multiple-antenna techniques constitute a key technology for modern wirelesscommunications, which trade-off superior error performance and higher data rates forincreased system complexity and cost. The algorithm used to eliminate inter channelinterference at the receiver. But The multiplexing gain of multiple antenna transmissionstrongly depends on transmit and receive antenna spacing and transmit antennasynchronization. In recent years, as a new method of antenna selection algorithm, thespatial modulation(SM) has become a hot research of many experts. Spatial modulationentirely avoids ICI and requires no synchronization between the transmitting antennaswhile maintaining high spectral efficiency is presented. A block of information bits ismapped into a constellation point in the signal and the spatial domain, i.e. into the locationof a particular antenna. The receiver estimates the transmitted signal and the transmitantenna number and uses the two information to de-map the block of information bits.In this paper, first of all, we introduced the system model of spatial modulation andseveral existing classical spatial modulation antenna select algorithm, and then proposethree improved algorithms base on the maximizing the channel capacity algorithm. Finally,the simulation results show the effectiveness in terms of reducing complexity, enhancingtransmission error rate and improving the effectiveness of the system performance.