Handover initiation across heterogeneous access networks for Next Generation Cellular Network

The heterogeneous networks are expected to become a main focus in the development toward the Next Generation Cellular Network (NGCN). The heterogeneous networks will allow users to move freely across different networks. However, the determination of the handoff initiation time is difficult in heterogeneous networks since many factors should be considered in the decision algorithm. Therefore, in this research, the main idea is early detection of the possibility of inter access system handoff and then to carry out registration of the mobile in the next domain before the actual handoff. In this paper, first the mathematical formulation for the length of the dynamic boundary area is derived as a function of users speed. Then, an adaptive value of Receive Signal Strength (RSS) threshold is proposed using the estimation of the boundary area to enable the mobile handoffs on time. Numerical analysis is done to evaluate the performance of the handoff initiation using the above mathematical formulations. By incorporating value of speed and handoff signaling delay into adaptive RSS calculation in advance, the system can make better preparation for the handoff so that the mobile handoffs on time.