Research On Interference Coordinaiton Technology In Wireless Communication System

With the continuous development of the wireless communication system of the cellular network, Orthogonal Frequency Division Multiplexing (OFDM) and Cognitive Radio (CR) technology have been proposed. OFDM is an efficient way to eliminate the interference between users within the cell. While, CR can achieve dynamic spectrum access without affecting the primary user communication. In this paper, we consider to study how to reduce the inter-cell interference (ICI), and secondary users spectrum access under the cellular network model.First, this paper describes the interference coordination techniques. Analyzing the principle of OFDM technology, and classical interference coordination schemes. Inter-cell interference coordination generally based on multi-cell cooperation, here we will make research on how to choose the cooperative cells. As one kind of interference coordination technique, Interference Alignment (IA) technique which is proposed in recent years tries to align the interference signals into a signal space. With a larger signal-to-noise ratio, near interference-free throughput performance can be achieved in the cellular network by the use of I A.Secondly, We pay attention to Coordinated multi-point (CoMP) technology regarded as the primary means to coordinate the inter-cell interference. In downlink coordinated multi-point transmission systems, base-stations (BS) adopt tri-sector antenna divide the cell into three fan sectors so that the interference between the neighborhood cellulars can be greatly dispelled. Base-stations computes the large scale Signal to Interference Ratio(SIR) for the served users, and cell match its users with ones in the other cells according to certain rules by sharing the large scale SIR information. It realizes a trade-off of SIR between the users in the center of the cellular and users on the edge of the cellular, in order to solve the low Signal to Interference plus Noise Ratio (SINR) problem which due to the ICI at cell edge.Thirdly, We do some research on IA, especially on the distributed IA based on minimum out-of-cell inference algorithm and subspace IA algorithm. This paper proposed a scheme by the use of IA and rearranged sector-antenna in order to avoid inter-cluster interference and greatly improve the spectral efficiency of each cell. By the use of the means of numerical simulation, we compared the proposed IA scheme to the scheme about user collaborative strategy mentioned in Chapter3on the spectral efficiency and outage capacity, and compared the two IA algorithm on Bit Error Rate (BER).Finally, we combined the distributed IA based on minimum out-of-cell inference algorithm and CR. In the distributed IA scheme, each transmitter adopts an unselfish approach to minimize the interference to unintended receivers, which is the defining feature if CR. Considering the spectrum sensing at secondary users, adopting distributed IA algorithm, so as to minimize interference to the primary user.