Research On Inteference Coexistence Strategy Of Heterogeneous Networks

Capacity and rates requirements to wireless communication network have been increasing due to wireless mobile communications business explosive growth. However, traditional single Macrocell network architecture has already been unable to meet such a huge demand on communication traffic. Therefore, to improve blind spots coverage and hotspot capacity and rates, the network chooses to deploy a variety of low power nodes in traditional cell of origin, which is called "Heterogeneous Networks (HetNet)" and has become an inevitable networking trend.At present,3GPP (The3rd Generation Partnership Project) standardization for LTE (Long Term Evolution) and LTE-A (Long Term Evolution Advanced) is in progress. An important work undertaken by3GPP RAN4(Radio Access Network) work group is the HetNet scenarios analysis and interference assessment.Following the work plan and the latest progress of3GPP RAN4Work Group, three typical HetNet scenarios, Macro-Micro network, Macro-Femto network and Macro-Relay network, are considered in this thesis. The main research and assessment work of this thesis include following aspects:Firstly, this thesis researched coexistence problem of two-tier network interference scenarios when Microcell is introduced to LTE or LTE-A system. When a Microcell base station is under the interference of a Macrocell base station and another Microcell base station at the same time, the blocking power and reference sensitivity are determined by simulation results. Specific research mainly consists of four parts:1) Analysis of the coexistence problem of two-tier network interference scenarios when Microcell is introduced into Macrocell are given;2) Simulation assumptions including the network topology, propagation model, methods of interference calculation and evaluation criteria, are provided;3) Simulation scenarios and system simulation parameters are given;4) Analysis of the simulation results and the values of blocking power and reference sensitivity under different scenarios, the reference proposals for implementation are given at the same time.Secondly, this thesis researched the interference caused by other systems to Femtocell base station and the interference caused by Femtocell base station to other systems when Femtocell is introduced to LTE or LTE-A system, and Femtocell link interference level is determined by simulation results. The research mainly includes:1) Interference scenarios when Femtocell is introduced into Macrocell are Analyzed;2) Simulation assumptions including network topology, system parameters, channel model and assessment criteria, are given;3) Specific simulation scenarios and performance evaluation criteria are provided;4) Simulation results including throughput statistics and SINR statistical distributions of full frequency reuse schemes and hopping schemes are compared, and recommendations of implementation are based on analysis of interference problems.Finally, this thesis researched the interference caused by other systems to Relay base station and the interference caused by Relay base station to other system when Relay is introduced to LTE or LTE-A system, and ACLR and ACS values of Relay access side and backhaul side are determined by simulation results. The research mainly includes:1) Interference scenarios are analyzed when Relay is introduced into Macrocell;2) Simulation assumptions including types of Relay base station, simulation scenarios, network topology, ACIR model, simulation process and evaluation criteria, are given;3) Simulation results of interference scenarios are provided by system level simulation;4) Recommendations of reasonable ACLR and ACS values of Relay access side and backhaul side are provided based on the simulation results.A brief summary is given at the end, and the future research directions related to this thesis are also pointed out.