Reserch On Interference Management And Suppression Scheme In Ultra Dense Networks System

Ultra-dense small cell network(UDN)is an effective approach to reuse the spectrum and achieve high data rate transmission for 5G cellular networks.However,the interference problem among the densely deployed small cell is intractable to address due to the spectrum resource sharing.In this paper,the requirements and challenges of UDN are analysed,and a new architecture dynamic small base stations(SBSs)clustering is introduced as the key function.This paper investigates the executable interference management scheme in order to improve the system throughput with higher resource utilization and better user experience,and two innovative algorithms are proposed as follows.The first innovative algorithms:The hypergraph clustering based resource allocation algorithm is presented in chapter three.This paper investigates the ultra-dense networks downlink resource allocation algorithm facing to arbitrary communication links sharing channels with multiple communication links.Aiming to optimize the network sum rate,the complexity is considerable due to the flexible interference relation.To reduce the complexity,the problem can be decomposed based on the time variance by two sub-problems:channel allocation and power allocation.For channel allocation,a clustering algorithm based on the hypergraph similarity of small cell user equipment(CUEs)is proposed,which constructs the SUE sharing set to enhance the clustering efficiency and conduces the complexity to beO(N2).For power allocation,a bisection algorithm which can rapidly converge to the optimal solution is introduced to further promote the system throughput.Simulation results demonstrate that the proposed hypergraph clustering based resource allocation algorithm achieves 20%higher performance for sum rate and 5dB gain for average SINR than that of the conventional graph algorithm.The second innovative algorithms:The interference-aware Stan Berger cooperative game based resource allocation algorithm is proposed in chapter four.Take significant cooperation opportunities within SBSs into consideration in the ultra-dense downlink networks,this paper characterizes the cooperative behaviors in the Stan Berger cooperative game-theoretic framework,where maximize the system sum utility performance.The Nash-product sum utility maximization problem is formulated,and the game process is decomposed into two stages.At the first stage,a local anchor is selected to be the leaders.The interference penalty price is set firstly,based on which the channel allocation schemes to all SBSs are determined.At the second stage,observing the interference penalty price and the channel allocation schemes performed by the local anchor,each SBS as the follower makes the transmit power strategy to achieve its optimal utility in a distributed manner.Because of the advantage of the game process,the local anchor is able to predict the reactions of each SBS and determine the optimal strategy accordingly.The closed-form of the optimal SE equilibria is derived,and the optimal sum utility equilibria is proved to be attainable.Simulation results valid the correctness of the mathematical derivation,besides,the proposed interference-aware Stan Berger cooperative game based resource allocation algorithm achieves the significant performance both for system sum utility and SBS fairness compared to the non-game algorithm.