Handoff Algorithm In Heterogeneous Networks Research Articles

Optimized Handoff Algorithm for Heterogeneous Networks

One of the most recent topics in wireless communications is the heterogeneous networks. The next generation wireless networks are being designed with a convergence vision in which a mobile user/device can link simultaneously to various wireless access networks (e.g. WLAN, cellular, WMAN). Today when we talk about wireless heterogeneous networks, the first thing that comes to our mind is the seamless connectivity to the access networks. The users move continuously from one place to another while maintaining their connectivity to one or another network. During their movement from one place to another, the user switch among various access networks according to their needs like video streaming, an ongoing call and many others. This switching of user from one particular network to another one is known as Vertical Handoff. In the proposed work, we are introducing a new optimized vertical handoff algorithm for the seamless connectivity of the users to the wireless heterogeneous networks. The proposed algorithm provides better connectivity to the networks with reduced number of redundant handoffs. In the proposed work, all the simulations are done in NS3 simulation network by taking into consideration various parameters which are necessary for taking handoff decisions. Here, we are using the convex optimization technique with Gradient Descent algorithm for taking optimized Vertical Handoff Decision. The results obtained are then compared with the existing handoff algorithms and it is concluded that the proposed Handoff Algorithm outperforms the existing ones.

Technique for order of preference by similarity to ideal solution based predictive handoff for heterogeneous networks

This study presents an efficient handoff algorithm for heterogeneous networks comprising macrocells, microcells, picocells, and femtocells. The proposed algorithm is based on call admission control (CAC) for selecting target base station (BS) from a list of neighbouring candidate BSs, as well as using the technique for order of preference by similarity to ideal solution (TOPSIS) as decision method. The introduced algorithm takes into account multiple criteria including measured received signal strength (RSS) and signal-to-interference-plus noise ratio (SINR), predicted RSS and SINR, and number of free resource blocks of neighbouring BSs. With the use of TOPSIS, neighbouring BSs are ordered based on their priority determined using the five mentioned criteria. Selection of target BS from ordered list is then performed using CAC. Also, coverage expansion is used to retain the connection when there is not any BS for handoff. In addition, in order to predict the RSS and SINR samples, the logistic smooth transition autoregressive model is used. Performance of the proposed algorithm is evaluated in terms of ping-pong rate, outage probability, and throughput. The results indicate efficiency of the proposed algorithm in reducing number of unnecessary handoffs while significantly increasing throughput and decreasing connection dropping when compared with conventional algorithms.

Vertical handoff algorithm in heterogeneous networks for reducing interference

A vertical handoff decision algorithm in heterogeneous networks composed of CDMA Cell Networks (CN) and Wireless Local Area Network (WLAN) is proposed to minimize the total interference in CDMA. The scope of WLAN is determined by minimizing interference and each communicating node shall handoff to WLAN as soon as it enters the scope. We first propose a model for heterogeneous networks, and based on it we obtain the close-form expression of interference. In order to minimize interference, we use simulation annealing method to get the WLAN radius, which is called basic algorithm. In order to reduce the interference further, we improve the basic and get the enhanced algorithm. Through numerical computing, we analyze the interference in condition of different call arrive rates, and results show that the enhanced can reduce interference more greatly than the basic.

Adaptive vertical handoff algorithm in heterogeneous networks

The integration of cellular network (CM) and wireless local area network (WLAN) is the trend of the next generation mobile communication systems, and nodes will handoff between the two kinds of networks. The received signal strength (RSS) is the dominant factor considered when handoff occurs. In order to improve the handoff efficiency, this study proposes an adaptive decision algorithm for vertical handoff on the basis of fast Fourier transform (FFT). The algorithm makes handoff decision after analyzing the signal strength fluctuation which is caused by slow fading through FFT. Simulations show that the algorithm reduces the number of handoff by 35%, shortens the areas influenced by slow fading, and enables the nodes to make full use of WLAN in communication compared with traditional algorithms.