Optimal Strategy Research Based On Femtocell And Macrocell Two-Tier Networks

As the development of data services and the growing of users’data requirement in wireless communication system, the system resources in3G system can no longer satisfy all these needs. To solve this problem, one kind of technology called Femtocell was present. Femtocell is a kind of plug-and-play base station equipment with low transmit power, it suits for home and office environment. It can provide high rate wireless access for users within its coverage area through connecting to IP based networks.Deploying Femtocell into macro cellular networks will influent the network structure. First the deployment of Femtocell will improve the performance of network and bring about serious cross-tier interference at the same time. It is very important to find a tradeoff method between advantages and disadvantages of Femtocell. Second the handover frequency between under-layer Macrocell and up-layer Femtocell will increase,so it is also necessary to design appropriate neighbor cell list self-configuration and self-optimization solution. By analyzing the research results of Femtocell, I concentrate my energy on interference problem and self-optimization of neighbor cell list in two-tier networks, and propose two creative solutions.First,aimed at the good points and bad points of Femtocell access modes,I propose a novel method to improve the network performance based on hybrid access mode. By Setting two handover conditions in Femtocell,we can achieve the goal of guarantee the users’quality of service without bringing about a large amount of signaling overhead.Second, I propose a neighbor cell list optimizing method in Femtocell scenario to make up for a deficiency of existing algorithms. This method take special considerations about registered users in closed access mode Femtocell to guarantee their data services. This method can increase the system capacity and at the same time decrease the outage rate of whole system.