Position Aware Vertical Handoff Decision Algorithm in Heterogeneous Wireless Networks

With the rapidly developed wireless techniques, many wireless networks are deployed with widely varying characteristics. In order to fully utilize the complementary heterogeneous networks, the mobile terminal (MT) may handoff from one network to another by many subjective or objective reasons. The handoff process can be divided by three parts. Firstly, select the best network among different available heterogeneous networks; Secondly, decide which the best objective BS is among some possible homogeneous BSs and when to trigger the handoff; Thirdly, start the signaling interaction to finish this handoff process. In this paper, we analyze the handoff decision part, and present a new position aware vertical handoff decision algorithm (PAHO). By using the precise position, moving velocity and direction information gaining from the Globe Position System (GPS) module of MT, and the beforehand downloaded base station (BS) location and coverage radius information, the MT can decide the best objective BS and the best moment to trigger a vertical handoff. The simulation results demonstrate the excellent performance of PAHO in strict checkout conditions. In addition, this handoff decision algorithm is completely implemented by MT alone, no needing any assistance from BS, and can be adopted by horizontal handoff also.