Achieving Handoff Optimization and Throughput Efficiency in Vehicular Networks

As users drive through the vehicular networks with high speed, they frequently associate with different access points in succession to maintain connectivity. Without careful designed association control policy, it may lead to large number of handoffs and inefficient connections, which can potentially incur unacceptable delays and poor throughput. In this paper, we propose a new association control scheme with the goal of reducing the frequency of handoffs and improving throughput for all vehicular users. The defined problem HMTE (Handoff Minimization and Throughput Efficiency) is mathematically described as a min-max programming. Since the HMTE problem is NP-hard, we propose an alpha-approximation(alpha >= 2) algorithm CHMTE to resolve it. CHMTE employs a novel method to simplify the original problem to the Minimum cost Maximum flow problem, which is solved in polynomial time. Extensive evaluations show that the proposed algorithm outperforms the existing schemes in terms of the handoff frequency and network throughput.