Research On The Call Admission Control Algorithm Of The Hierarchical Heterogeneous Network

With the rapid popularization of the Internet and development of communication technology, the hierarchical heterogeneous characters of coverage in networks become more and more common and clear, which is caused by the need of low latency and high quality for wireless applications to users.In this hierarchical heterogeneous wireless network system, radio resource management strategies such as an appropriate access control algorithm can intergrate and allocate radio resources effectively, thereby improving the resource utilization and promoting user satisfaction and quality of service. The main works are as follows:Firstly, the thesis introduce the concept of radio resource management(RRM) in heterogeneous wireless network, and then its several key technologies: Call admission selection and control, Vertical handoff(VHO) and Load balancing(LB) are introduced. According to the characteristics of heterogeneous wireless network, an access selection algorithm based on Markov process is proposed to provide users with the best connection anytime and anywhere in LTE-A/WLAN Heterogeneous Network. Simulation results show that the proposed algorithm can effectively enhance the throughput of the heterogeneous network, decrease the total blocking probability and improve the resource utilization.Secondly, a three-dimensional Markov chain model has been proposed for the performance evaluation of RAT selection algorithms in a three co-located network. Numerical results obtained from this model are validated by simulation results. The LB and service based RAT selection algorithms have been compared using the proposed analytical model. The results show that the LB based algorithm outperforms the service based algorithm in terms of call blocking probability.Finally, the complete signaling flow for handover procedure in different scenarios is proposed according to the LTE femtocell-macrocell integrated network architecture, and in order to minimize the unnecessary handovers, a call admission control scheme respecting different criterias, such as SINR and the speed status of UE is proposed. The results show that the integrated network system increases the macrocell channel release rate. The inter-HeNB handover and the hand-in handover probabilities are increased, when the number of deployed femtocells increases. However, the hand-off handover probability is decreased although its value is very high.