Pls I need source code on the vertical handoff algorithm

Next-generation heterogeneous networks support an interoperability environment that demands seamless mobility management. To enable ongoing communication activity, handover technology is designed to allow users to roam across networks. When the connection switches between different networks, the handover is known as vertical handoff, whereas handoff that takes place within the same network is referred to as horizontal handoff. The vertical handover process involves three phases [1], i.e., the system discovery phase, handoff decision phase and handoff execution phase. Providing efficient association with a suitable wireless network remains an open challenge in heterogeneous networks. Recent research has suggested few approaches that give directional assistance in selecting a candidate network during the handoff decision phase. However, it has become essential to offer an efficient handover mechanism to meet different QoS requirements and maximize the resource utilization of the network. In addition, the literature reveals that various metrics such as signal strength, bandwidth, bit error rate, power consumption, and cost evaluation to determine the selection of a candidate network. These metrics might be suitable when horizontal handoffs are initiated but become insufficient to trigger vertical handoffs due to different system characteristics. Design of the required Quality of Services (QoS)-aware vertical handover decision algorithm is another major concern in such a scenario. The vertical handoff mechanisms are generally grouped in terms of mobile-controlled handoff and network-controlled handoff processes. Various mobility management strategies for QoS support designed in the literature are based on mobile-controlled handoff. Therefore, such a design cannot select the best network for mobile devices because the device has limited power and limited information on the networks. In such a case, the ping-pong effect is high because the selection of the network is based on previous history stored in the mobile terminal. System efficient performance in terms of handover delay and the handover decision degrades due to this handover failure. The methods reported in the literature so far to solve this complex problem suffers from one or more of the following limitations—inappropriate vertical handover routing metrics, lack of proactive congestion check in the candidate network and mobile-controlled handoff that are addressed in this study. The goals of the proposed work are to reduce handover failures and to derive the required QoS support based on network controlled handoff for heterogeneous networks. The first stage of the proposed work implements the Technique to order preference by similarity to the ideal solution (TOPSIS) method, which is defined under the Multi-Attributed Decision Making method (MADM). Using this method, the appropriate ranking for each decision variable involved in the network model is obtained. The second stage of this work carries the recursive dynamic programming construction with zone-based decisions imposed on the network control side. This paper presents a new and efficient dynamic programming approach known as TOPSIS with Knapsack Vertical handover Decision (TOPSIS-KVD), an optimal solution for vertical handover challenges in next-generation networks with greatly reduced handover failures. The limit for the mobile terminal in performing handover with network congestion under check is decided via dynamic programming that determines the decision alternatives for the best network selection. The proposed TOPSIS KVD generates vertical handover decisions by taking into consideration of the significant metrics such as signal strength, RTT, reliability, cost and traffic handling priority of the candidate network. This work demonstrates an efficient direction for optimal network selection, thereby reducing the challenges of handover failure between WiMax networks and Wi-Fi networks for various QoS traffic classes. The proposed TOPSIS-KVD incorporates a simple design that achieves seamless handover over fuzzy based design and removes the ping-pong effect.

The remainder of this paper is organized as follows. Section 2 provides an overview of selected related works for vertical handover decision mechanisms. Section 3 presents a system model for implementing the proposed TOPSIS-KVD approach for the selection of the optimal network, and the simulation results are presented in Section 4. Conclusion and observations are provided in Section 5. Section 6 gives the current limitations of the proposed work and future direction.