The Evaluation Method And The Test Validation Of Load Balancing Between CDMA And LTE

With the development of heterogeneous networks, there are many overlapping coverage scenarios between different networks. On one hand, China Telecom needs to speed up the construction of LTE base stations to meet the demand of LTE coverage. On the one hand, the company needs to take the existing CDMA network into account, guaranteeing the network communication quality of service. In the current situation, generally the priority of LTE is higher than that of CDMA network. Users' terminals will reside firstly to the LTE networks. However, faced with a growing number of UEs, the load of the cells will be higher. The quality of users' communication will be seriously influenced without load balancing. On the basis of the realistic challenge, China Telecom needs to deal with the load balancing between CDMA and LTE.Relying on “National Science and Technology Major Projects”, this thesis regards networks overlap-cover scene between CDMA and LTE as the research model. Based on the existing simulation platform, a load balancing evaluation method between CDMA and LTE is proposed. A lot of tests have been carried out to verify the algorithm. Three main aspects are included in this thesis as follows:First of all, the theoretical knowledge of CDMA network, LTE, frame structure, the principle of load balancing technology is expounded in the thesis. The load balancing implementation scheme between CDMA and LTE system is deeply analyzed. The key parameters are defined, and the existing simulation platform is stated from aspects of the function architecture and network units.Secondly, based on the interoperability between CDMA and LTE, the thesis puts forward a double-threshold load balancing algorithm between different systems.This algorithm considering both the load difference between the different neighborhood cells and the load of a single cell with the double-threshold load as the primary switch judgment basis.On the premise of meeting the double-threshold load, determining users' received signal strength based on the B2 event. The handover will be executed if the B2 event is triggered. On the other hand, the handover will not be executed. The algorithm meets the requirement of the load balancing in the subject.Finally, the test verification of the load balancing evaluation method is executed via the existing simulation platform. Because of the different network frame structure, the load should be normalized to achieve the purpose of synchronization simulation between different systems. The thesis tests the load balancing of CDMA/FDD and CDMA/TDD respectively. The system performance berfore and after load banancing is compared from the user rate, the system average throughput, radio link failure, RB occupancy rate, the optimal load-double threshold, handover frequency. Simulation results show that the load balancing algorithm between different systems can improve the system performance effectively.At present, the subject achievement has been delivered, which gets the approval of Guangzhou Research Institute of China Telecom and National Science and Technology Major Projects.