Research And Design Of Ultra Dense Network Synchronization Algorithm Based On Interference Coordination

Ultra-dense networking will be the main technology to meet the demand of 5G and future mobile data traffic.Ultra-dense networking can achieve higher frequency reuse efficiency through the deployment of more "intensive" small base stations,thus achieving a hundredfold increase in system capacity in local hot spots.Synchronization is the basis of cellular network communication,but with the increasing of small base stations in the region,the strong interference between small base stations will have an impact on synchronization that cannot be ignored.Only when the base stations in the region complete synchronization,can the advanced inter-cell cooperation and interference elimination technology be combined to maximize the advantages brought by the ultra-dense network.Therefore,this thesis mainly studies the base station synchronization problem in ultra-dense networks under strong interference.Firstly,a clustering shortest path synchronization algorithm is proposed for the problem of small base station synchronization in macro-micro deployment scenarios in ultra-dense network.The algorithm is about the strong inter-base station interference problem in ultra-dense network.It combines the clustering and the shortest path and determines the path of the base station to be synchronized to listen to the reference base station with the maximum ratio of signal to interference and noise between the base stations.The base station obtain synchronization information and realize clock synchronization according to the result of the synchronization path,listening to and parsing the synchronization reference signal.According to the simulation results,the algorithm improves the base station synchronization ratio in the region and reduces the base station synchronization error in the region than traditional air interface synchronization algorithm.Secondly,The thesis proposes a distributed network synchronization algorithm for researching the synchronization problem of small base stations in micro-micro scenes in ultra-dense network.As for the problem of densely-deployment of base station and strong interference in ultra-dense network,the algorithm,which modifies the timing information of the base station at the next moment according to the neighbor base station in order to the base station timing synchronization,selects the neighboring base station set for each base station by using the signal-to-interference ratio among the base stations.The simulation results show that the proposed algorithm achieved distributed synchronization of base stations in the area without macro base station,and has better synchronization convergence.Finally,the thesis designed a synchronization protocol which was practically applied in ultra-dense network.The synchronization process of the small base station is completed by an SDN(Software Defined Networking)controller.The protocol is divided into four parts: a control module,a centralized synchronization module,a distributed synchronization module,and a monitoring module in implementation.In the ultra-dense networking scenario built in the lab,the centralized synchronization process and distributed synchronization process of the synchronization protocol were tested.The test results show that the designed synchronization protocol can achieve base station synchronization in ultra-dense networks.