SINR Based Vertical Handoff Scheme for QoS in Heterogeneous Wireless Networks

Next generation wireless network is envisioned as a convergence of different wireless access technologies providing the user enhanced connection any where any time to improve the systems resource utilization. In such converged systems, co-existence of heterogeneous access technologies with largely different characteristics like data rate for wideband code division multiple access (WCDMA), wireless local area network (WLAN) results in handoff asymmetry that differs from the traditional intra-network handoff (horizontal handoff). Thus handoff between different access technologies (vertical handoff) is essential and remains a challenging issue. The vertical handoff (VHO) algorithm must be quality of service (QoS) aware. Conventionally, handoff analysis is performed using well known vertical handoff metric, received signal strength (RSS). In this paper, a more appropriate handoff parameter, signal to interference and noise ratio (SINR) is used to assess the system performance in terms of dropping probabilities in addition to throughput. Simulation results prove that the proposed SINR based vertical handoff scheme offers enhanced system throughput and relatively low dropping probabilities when compared to the existing RSS based handoff scheme.