The Resource Allocation And Interference Management Technologies Research In 5G Ultra-dense Network

Ultra-dense network is expected to deploy with of a large number of unplanned low-power wireless access points,and each access point is closed to each other,resulting in its more complex interference environment relative to the traditional cellular network.And there may exit the interference source that traditional interference management mechanisms and signal detection techniques can not eliminate.That is,the traditional interference suppression techniques such as inter-cell interference coordination and enhanced inter-cell interference coordination in the ultra-dense network is limited.Therefore,ultra-dense network needs much stricter resource management and interference management programs to eliminate the relatively strong interference to enhance the performance.In addition,user-centric virtual cell technology is considered to be one of the key technologies of 5G ultra-dense network,and the virtual cell transmission mechanism can well suppress the interference in this random topology network.This paper begins with the ultra-dense network,and studies transmission mechanisms and optimization algorithms with good interference suppression capacity in the direction of resource management,interference management and virtual cell.The present study proposed a subcarrier and power allocation scheme based on iterative approximate water-filling algorithm.A convex optimization model is formulated to maximize the system spectrum efficiency.Then,a low-complexity iterative approximate water-filling algorithm is proposed to solve the approximated model.The proposed algorithm can avoid the iterative power allocation step,which must revise the water line after getting the power of each subcarrier.It can solve the power allocation directly by some algorithms,greatly reducing the computational complexity.Simulation results and analysis show that the proposed low-complexity iterative approximate water-filling algorithm can not only attain the spectrum efficiency performance of the traditional iterative water-filling algorithm within few iterations times,and but also reduce the complexity of the algorithm significantly.This paper aims to mitigate the large and complex interference in downlink ultra-dense networks and proposed a downlink transmission scheme based on virtual cell clustering.Based on the large-scale information between the user and the distributed antenna,the scheme first constructs an interference graph.It represents the potential interference strength between each user's virtual cell.Then the virtual cell is clustered by the interference map.Finally,the interference in the cluster is eliminated by using the interference alignment.The simulation results show that the proposed algorithm based on virtual cell clustering can obtain a better average user rate than the zero-forcing scheme and the maximum rate transmission scheme.Further research work can be carried out from the ultra-dense network resource management and interference management in the line-of-sight transmission mode.