Vertical Handoff Decision Research Articles

Vertical handoff decision in 4G wireless networks using multi attribute decision making approach

Multi-interface terminal in heterogeneous wireless networks will have network access from diverse access technologies. Multiple attribute for decision making including user preference will increase the complexity of handoff process. Various approaches have been proposed to solve the complexity problem of handoff decision. In this paper, multi attribute decision making algorithms Analytic Hierarchy Process (AHP) method, Simple Additive Weighting (SAW), Total Order Preference by Similarity to the Ideal Solution (TOPSIS), and Grey Relational Analysis (GRA) methods have been proposed for handoff decision in a WiMAX–WLAN environment to facilitate user with better quality of service. AHP has been used for calculation of weights of decision parameters. Numerical results show that SAW, TOPSIS and GRA provide almost similar performance. SAW is very simple to implement but probability of error is less in GRA because values of decision attribute are directly used for ranking of alternatives. TOPSIS is sensitive to the attribute with high score.

Markov-based vertical handoff decision algorithms in heterogeneous wireless networks

In this paper, we propose a received signal strength (RSS)-based single-attribute handoff decision algorithm at first, and investigate handoff decision model based on connection lifetime, which can keep mobile terminals (MTs) staying long enough in the preferred network. Since the preferred quality of service (QoS) parameters may be distinct among different MTs, we then formulate the vertical handoff decision problem as a Markov decision process, with the objectives of maximizing the expected total reward and minimizing average number of handoffs. A reward function is constructed to assess the QoS during each connection, and the G1 and entropy methods are applied in an iterative way, by which we can work out a stationary deterministic handoff decision policy. Numerical results demonstrate the superiority of our proposed schemes compared with other existing algorithms.

Design of Vertical Handoff Initiation and Decision Algorithm in Heterogeneous Wireless Networks

Vertical handoff decision (VHD) algorithms are essential components of the architecture of the forthcoming Fourth Generation (4G) heterogeneous wireless networks. These algorithms need to be designed to provide the required Quality of Service (QoS) to a wide range of applications while allowing seamless roaming among a multitude of access network technologies. This work mainly focuses on vertical handoff initiation and decision. The handoff initiation is critically important to keep the unnecessary handoffs and their failures at a low level. On the other hand, to maximize the end-user’s satisfaction levels, the decision to select the best network among other available candidates also plays an important role. The proposed algorithm provides a complete framework to perform vertical handoffs in a heterogeneous wireless network.

Performance Analysis of Fuzzy Logic Based Vertical Handoff Decision Algorithm for Heterogeneous Networks

Performance Analysis of Fuzzy Logic Based Vertical Handoff Decision Algorithm for Heterogeneous Networks

A Markov-Based Multi-Attribute Vertical Handoff Decision Algorithm

Many vertical handoff decision algorithms have not considered the impact of call dropping during the vertical handoff decision process. Besides, most of current multi-attribute vertical handoff algorithms cannot predict users’ specific circumstances dynamically. In this paper, we formulate the vertical handoff decision problem as a Markov decision process, with the objective of maximizing the expected total reward during the handoff procedure. A reward function is formulated to assess the service quality during each connection. The G1 and entropy methods are applied in an iterative way, by which we can work out a stationary deterministic policy. Numerical results demonstrate the superiority of our proposed algorithm compared with the existing methods.

A Novel PROMSIS Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks

A novel preference ranking organization method by similarity to ideal solution (PROMSIS) vertical handoff algorithm is proposed for heterogeneous wireless networks, and its essential idea includes the preference structure of the PROMETHEE and the concept of Euclid distance of the TOPSIS. Four 3GPP defined traffic classes are considered in performance evaluation. An attribute matrix is constructed considering some major attributes. Handoff decision meeting multiattribute QoS requirement is made according to the traffic features. The weight relation of decision elements is determined with the least square (LS) approach. The final decision is made using the proposed PROMSIS algorithm based on the attribute matrix and weight vector. The simulation results have manifested that the proposed PROMSIS algorithm can provide satisfactory vertical handoff performance, and the LS-PROMSIS algorithm can be fit to the characteristics of the traffic.

Research on vertical handoff decision based on service history information and SINR for heterogeneous wireless networks

In this letter, we propose a SH (Service History) and SINR (Signal to Interference plus Noise Ratio) based PROMETHEE (SHS-PROMETHEE) vertical handoff (VHO) decision algorithm. An attribute matrix is constructed considering the SH information and the SINR in the source network and the equivalent SINR in the target network and so on. Handoff decision meeting multi-attribute QoS requirement is made according to the traffic features. The weight relation of decision elements is determined with LS method. Finally decision is made using PROMETHEE algorithm based on the attribute matrix and weight vector. The simulation results have shown that the SHS-PROMETHEE algorithm can reduce unnecessary handoffs and provide satisfactory vertical handoff performance.

Vertical Handoff Algorithm Based on Type-2 Fuzzy Logic in Heterogeneous Networks

Cu rrently, to ensure seamless roam across heterogeneous wireless technologies, efficient vertical handoff algorithms are required to enhance QoS and offer reliable pervasive computing environment. This study re views traditional and classical artificial intelligent approaches adopted for vertical handoff across heterogeneous networks. A type-2 fuzzy multi-parameter based vertical handoff decision algorithm is proposed. The proposed algorithm considers five parameters of network and user , and applies a multi-mode smart terminal based speed adaptive vertical handoff policy . The speed adaptive policy overcomes the update drawbacks of the fixed, single network discovery methods by using RSS in the network discovery phase . Simulation results show that the proposed algorithm can effectively improve the network update speed, lower network blocking probability, and assure the effectiveness and fairness of handoff compared with vertical handoff algorithm based on traditional fuzzy logic .

A fuzzy-based intelligent vertical handoff decision strategy with maximised user satisfaction for next generation communication networks

A vast diversity of services over the available radio access networks is assured by the next generation wireless systems for consumers with multi-homed cellular devices. Many consumer centric economic surplus-based vertical handoff schemes were already proposed intending to profit the end user. Few of these schemes estimate consumer surplus value with respect to the data transfer completion time assessed against the time constraints agreed by the user. In this paper, we suggested a vertical handoff decision strategy which promises maximised user satisfaction for consumer surplus value-based pricing schemes for non real time mobile-based multi-media services. A fuzzy rule-based system supported by multi criteria decision model is proposed to find optimum network between consumer surplus value and file download culmination time with the objective of maximising user satisfaction. Simulation is carried out using OM Net++ and MATLAB and the results are acknowledged with discussion and analysis.

Vertical Handover in Next Generation Wireless Networks

The next generation wireless networks will support the vertical handoff procedure in which users can keep the connections when they change from one access network to another. Although diffferent vertical handoff decision algorithms have been proposed in the literature recently. This paper presents an exhaustive state of the art survey about handover alogorithms in heterogeneous networks. With the advent of novel networks technologies, researchers have been working on how to implement and ensure that QoS is achieved in heterogeneous networks. We believe that there have been some improvements, but there is much to do. Additionally, the survey shows the great effort which has been undertaken by the research community in order to address the topic over these years. The blooming of ideas is plethoric and gives us a view about the tremendous scope covered by the subject.

Artificial Neural Network Based Vertical Handoff Algorithm for Reducing Handoff Latency

One of the most challenging topics for next generation wireless networks is vertical handoff concept since several wireless technologies are assumed to cooperate. Plenty of parameters related to user preferences, application requirements, and network conditions, such as; data rate, service cost, network latency, speed of mobile, battery level, interference ratio and etc. must be considered in vertical handoff process along with traditional RSSI information. In this study, a new artificial neural network based handoff decision algorithm is proposed in order to reduce the handoff latency of smart terminal deployed in aforementioned wireless heterogeneous infrastructures. The prominent parameters data rate, monetary cost and RSSI information are taken as inputs of the developed vertical handoff decision system. Performance results of the proposed system are also compared with those of classical Multiple Attribute Decision Making method Simple Additive Weighting, and of some other artificial intelligence based algorithms. According to the results obtained, the proposed neural network based vertical handoff decision algorithm is able to determine whether a handoff is necessary or not properly, and selects the best candidate access network considering the abovementioned parameters. The results also show that, the neural network based algorithm developed significantly reduces the handoff latency while the number of handoffs, which is another vital performance metric, is still reasonable.

QoS-aware fuzzy rule-based vertical handoff decision algorithm incorporating a new evaluation model for wireless heterogeneous networks

Abstract Abstract Next generation networks are envisioned to be heterogeneous in nature with an increase in demand towards ubiquitous services in wireless networks. As various networks have widely different characteristics, it is difficult to maintain the quality of service (QoS) after executing a handoff from one network to another network. Maintaining the QoS, based on applications, during the handoff in an heterogeneous networks needs an intelligent handoff decision mechanism. This article proposes a QoS-aware fuzzy rule-based vertical handoff mechanism that makes a multi-criteria-based decision, found to be effective for meeting the requirements of different applications in a heterogeneous networking environment. The QoS parameters considered are available bandwidth, end-to-end delay, jitter, and bit error rate. A new evaluation model is proposed using a non-birth–death Markov chain, in which the states correspond to the available networks. Simulation results show that compared to other vertical handoff algorithms, the proposed algorithm gives better performance for different traffic classes.

Research on Vertical Handoff Decision Based on PROMETHEE Algorithm for Heterogeneous Wireless Networks

Research on Vertical Handoff Decision Based on PROMETHEE Algorithm for Heterogeneous Wireless Networks

Immune optimization algorithm for solving vertical handoff decision problem in heterogeneous wireless network

In heterogeneous wireless network environment, wireless local area network (WLAN) is usually deployed within the coverage of a cellular network to provide users with the convenience of seamless roaming among heterogeneous wireless access networks. Vertical handoffs between the WLAN and the cellular network maybe occur frequently. As for the vertical handoff performance, there is a critical requirement for developing algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a mathematical model for vertical handoff decision problem, and propose a multi-objective optimization immune algorithm-based vertical handoff decision scheme. The proposed scheme can enable a wireless access network not only to balance the overall load among all base stations and access points but also maximize the collective battery lifetime of mobile terminals. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed scheme.

Evaluation of Vertical Handoff Decision Algorightms Based on MADM Methods for Heterogeneous Wireless Networks

In the forthcoming heterogeneous wireless environment, the mobility management of users roaming between different wireless access technologies is a challenging and important technical issue. New mobile devices such as netbooks, smartphones and tablets allow users to perform vertical handoffs among different wireless networks. The multiple attribute decision making (MADM) methods are suitable tools to model and study the vertical handoff process. Hence, recently several MADM methods such as SAW, MEW, TOPSIS, GRA, ELECTRE, VIKOR and WMC have been proposed for vertical handoff. In this paper, we present an extensive performance evaluation and comparative study of the seven MAMD methods by means of numerical simulations in MATLAB. We evaluate the performance of each vertical handoff method under different applications such as voice, data, and cost-constrained connections. We also perform a sensitivity analysis and evaluate the computational complexity of each method in terms of number of floating point operations.

A Cross Layer based Vertical Handoff Decision Making Framework

Emerging wireless communication technology focuses the development to provide the communication support for mobile devices based on the user demand and network connectivity for high-speed data transfer like multimedia, video and Voice over IP(VoIP). In wireless network the main issue to be addressed is channel allocation and network connectivity. Because of the limited bandwidth resources, it is necessary to provide an efficient solution for bandwidth allocation to increase number of users. Maintaining the network connectivity improves the user satisfaction. Because of the mobility of user and continuous changes in network characteristics like bandwidth, error rate, delay and jitter assigning the „best‟ network channel is a challenging issue. Handover process has been done to maintain the connectivity. During handover choosing the best network with the QoS guarantee based on the user requirements and service type is the current research topic. Several works is going on in this area. Still there is no standard and efficient method implemented in real world. This paper proposes a frame work to make decision to choose the best network while handoff is triggered.

Seamless handoff across heterogeneous networks: A multi-objective optimization approach

The growing consumer's demand leads a great access to communication services anywhere and at anytime. It has started to accelerate the development of technologies that would allow for the integration of various Wireless Access Technologies. With regard to vertical handoff performance, there is a critical need for developing algorithms for connection management and optimal resource allocation for seamless mobility. This study proposes a novel Vertical Handoff Decision Making Algorithm (VHDMA) based on analytic multi-objective optimization. The multi-objective cost function involves transmit power of Mobile Terminals (MTs), outage and throughput over Access Points (APs)/Base Stations (BSs). The proposed algorithm lowers the barriers and jointly optimizes all the required objectives. The results showed that the Multi-Objective (MO) optimization has the advantages of optimizing over different and conflicting objectives jointly. Key words: Seamless mobility, heterogeneous networks, multi-objective (MO) optimization, vertical handover.

Case study on handoff strategies for wireless overlay networks

One of the most challenging topics for next‐generation wireless networks is the process of vertical handoff since many of wireless technologies overlap each other and build a heterogeneous topology. Several parameters, pertaining to user/application requirements and network conditions, such as data rate, service cost, network latency, speed of mobile, and etc. must be considered in the handoff process of heterogeneous networks along with RSSI information. In this paper, adaptive fuzzy logic‐based vertical handoff decision‐making algorithms are presented for wireless overlay networks which consist of GSM/GPRS/Wi-Fi/UMTS/WiMAX technologies. The parameters data rate, monetary cost, speed of mobile and RSSI information are processed as inputs of the proposed fuzzy‐based systems. According to these parameters, an output value, which varies between 1 and 10, is produced. This output value is utilized to determine whether a handoff process is necessary or not and to select the best candidate access point in the vicinity. The results show that, compared to the traditional RSSI‐based algorithm significantly enhanced outcomes can be achieved for both user and network as a consequence of the proposed fuzzy‐based handoff systems. The simulation results are also compared with those of classical MADM (Multiple Attribute Decision Making) method, i.e. SAW (Simple Additive Weighting). According to the results obtained, the proposed vertical handoff decision algorithms are able to determine whether a handoff is necessary or not, properly, and select the best candidate access network considering the aforementioned parameters. Moreover, fuzzy‐based algorithm noticeably reduces the number of handoffs compared to SAW‐based algorithm.

Fast Decision Algorithms in Low-Power Embedded Processors for Quality-of-Service Based Connectivity of Mobile Sensors in Heterogeneous Wireless Sensor Networks

When a mobile wireless sensor is moving along heterogeneous wireless sensor networks, it can be under the coverage of more than one network many times. In these situations, the Vertical Handoff process can happen, where the mobile sensor decides to change its connection from a network to the best network among the available ones according to their quality of service characteristics. A fitness function is used for the handoff decision, being desirable to minimize it. This is an optimization problem which consists of the adjustment of a set of weights for the quality of service. Solving this problem efficiently is relevant to heterogeneous wireless sensor networks in many advanced applications. Numerous works can be found in the literature dealing with the vertical handoff decision, although they all suffer from the same shortfall: a non-comparable efficiency. Therefore, the aim of this work is twofold: first, to develop a fast decision algorithm that explores the entire space of possible combinations of weights, searching that one that minimizes the fitness function; and second, to design and implement a system on chip architecture based on reconfigurable hardware and embedded processors to achieve several goals necessary for competitive mobile terminals: good performance, low power consumption, low economic cost, and small area integration.

Handover Necessity Estimation for 4G Heterogeneous Networks

One of the most challenges of 4G network is to have a unified network of heterogeneous wireless networks. To achieve seamless mobility in such a diverse environment, vertical hand off is still a challenging problem. In many situations handover failures and unnecessary handoffs are triggered causing degradation of services, reduction in throughput and increase the blocking probability and packet loss. In this paper a new vertical handoff decision algorithm handover necessity estimation (HNE), is proposed to minimize the number of handover failure and unnecessary handover in heterogeneous wireless networks. we have proposed a multi criteria vertical handoff decision algorithm based on two parts: traveling time estimation and time threshold calculation. Our proposed methods are compared against two other methods: (a) the fixed RSS threshold based method, in which handovers between the cellular network and the WLAN are initiated when the RSS from the WLAN reaches a fixed threshold, and (b) the hysteresis based method, in which a hysteresis is introduced to prevent the ping-pong effect. Simulation results show that, this method reduced the number of handover failures and unnecessary handovers up to 80% and 70%, respectively.