Equivalence Analysis of Vertical Handoff for Cells with Various Scales

To improve the efficiency of field test, a new integrated wireless test ring (T-Ring) system is planned to be established. In this system, the cell radius will be proportionally reduced. To study the vertical handoff between WLAN and cellular networks of the T-Ring system, we need to analyze vertical handoff quantitatively. Based on the analysis result, the corresponding parameters will be adjusted to make the test system equivalent with the realistic system. Vertical handoff probability and handoff blocking probability are the two most important parameters which characterize the vertical handoff. We derive the close form of these two parameters for WLAN-first handoff scheme. To guarantee these parameters equivalent with those of the realistic system, speed of the mobile user and average load of the cellular networks should be adjusted with the cell size. A method of parameter adjustment is proposed by numerical calculation and theoretical analysis. Simulation results show that our method is precise enough. The analysis result is also applicable to other realistic micro cells systems.