An improved TOPSIS vertical handoff algorithm for heterogeneous wireless networks

In this paper, we propose a SINR(Signal to Interference plus Noise Ratio), AHP(Analytic Hierarchy Process) and information Entropy weight method based TOPSIS (SAE-TOPSIS) vertical handoff algorithm which uses the combined effects of SINR with SINR value from one network being converted to equivalent SINR value to the target network for getting the same data rate, user required bandwidth, user traffic cost and available bandwidth of the participating access networks to construct the attribute matrix and make handoff decisions for multi-attribute QoS consideration according to the features of the traffic. For performance evaluation, four traffic classed defined by 3GPP are considered. The subjective weight relations of decision elements are determined by eigenvalue method of AHP. Next, the information entropy method is employed to derive the objective weights of the evaluation criteria and on the basis, the comprehensive weight is obtained. Finally we use TOPSIS algorithm to make decision according to the attribute matrix and weight vector. The results show that our proposed scheme can achieve excellent performance according to the characteristics of the traffic by considering the relations of multiple attributions synthetically.