Design Of Interference Management Mechanism And Overhead Control In Cellular Networks

The contradictory between spectrum scarcity and its under-utilization becomes one of the critical problems limiting system performance,improving spectral efficiency and throughput to meet the rapidly growing demand for high-speed data transmission is of great importance to wireless communication service providers.In particular,as the frequency reuse efficiency improves,cell-edge users suffer more co-channel interference(CCI)from adjacent cells,which degrades the overall system performance.Deploying small cells in a wireless network can improve indoor coverage and boost spectral efficiency per unit area via spatial reuse,but the deployment of small cells will originate new cell boundaries,in which end users may suffer from strong inter-cell interference,degrading the performance of the overall cellular network.Therefore,how to effectively suppress interference in the network is the focus of this paper.At First,Both interference alignment(IA)and interference neutralization(IN)are exploited for Coordinated Multi-Point(Co MP)transmissions is proposed.With the base station's cooperation,the precoding vectors are designed to achieve IA and IN at the transmitter's side,and receivers adopt zero-forcing(ZF)reception to cancel the residual interferences and recover the desired data.The proposed interference alignment and neutralization based Co MP mechanism(IAN-Co MP)can achieve effective interference cancellation and suppression by exploiting limited and flexible collaboration only at the base station(BS)side,and concurrent transmissions of multiple data streams are achieved.We also extend the mechanism to general cases where the antenna configurations at both transmitter and receiver side,the number of transmitters participating in Co MP and simultaneously served users are variable.In addition,the proposed scheme can also achieve a flexible tradeoff between cooperation overhead and the system's achievable degrees of freedom.Our in-depth simulation results show that IAN-Co MP can significantly improve the spectral efficiency(SE)for cell-edge users.Then,a joint adaptive interference management(JAIM)mechanism exploiting multi-dimensional resource is proposed for downlink transmission in heterogeneous cellular networks(HCNs)consisting of overlapping macrocell and picocells.The scheme manages the interference from macro base station(MBS)to pico user equipment(PUE)by taking practical factors such as path loss,inter-BS distance and transmit power difference of BSs into account.Firstly,we define the efficiency of interference management(IM),based on which the criterion for adaptive IM is derived.Then,the design of JAIM is elaborated by taking interference neutralization and zero-forcing reception as an example.The theoretical analysis and simulation results show that by exploiting multi-dimensional resource the proposed mechanism avoids the dependence of single IM method on specific resource,and achieves the improvement of the pico users' spectral efficiency without influencing the macro users'.Finally,we conclude the research work and give directions for the future work.