Heterogeneous Wireless Environment Research Articles

Optimal Network Selection in Heterogeneous Wireless Environment for Multimedia Services

In wireless communication, new radio access technologies are emerging, capable of supporting larger coverage area and faster data rates. In a wireless heterogeneous environment consisting of disparate radio access technologies, selection of the best network is an important research issue. In this paper, we propose a novel network selection algorithm for a heterogeneous environment consisting of WiMAX and LTE standard. The proposed algorithm is based on received signal strength, signal to noise ratio, available bit rate, achievable throughput and bit error rate. Relative weights of the decision making attributes are optimized by employing particle swarm optimization approach. The number of satisfied users calculated (as per their demand with wireless network selected) by proposed algorithm is optimized by modified PSO and confirmed by Monte Carlo method. From the simulation results it is inferred that the number satisfied users while running multimedia applications has been improved by 50 % as compared to the existing network selection algorithms.

A Novel Model on Curve Fitting and Particle Swarm Optimization for Vertical Handover in Heterogeneous Wireless Networks

The vertical handover mechanism is an essential issue in the heterogeneous wireless environments where selection of an efficient network that provides seamless connectivity involves complex scenarios. This study uses two modules that utilize the particle swarm optimization (PSO) algorithm to predict and make an intelligent vertical handover decision. In this paper, we predict the received signal strength indicator parameter using the curve fitting based particle swarm optimization (CF-PSO) and the RBF neural networks. The results of the proposed methodology compare the predictive capabilities in terms of coefficient determination (R2) and mean square error (MSE) based on the validation dataset. The results show that the effect of the model based on the CF-PSO is better than that of the model based on the RBF neural network in predicting the received signal strength indicator situation. In addition, we present a novel network selection algorithm to select the best candidate access point among the various access technologies based on the PSO. Simulation results indicate that using CF-PSO algorithm can decrease the number of unnecessary handovers and prevent the “Ping-Pong” effect. Moreover, it is demonstrated that the multiobjective particle swarm optimization based method finds an optimal network selection in a heterogeneous wireless environment.

Heterogeneous wireless network vertical handoff decision using hybrid multi-criteria decision-making technique

The selection of the most appropriate network in a heterogeneous wireless environment is one of the critical issues to provide the best quality of service QOS to the users. The selection of an apt network among various alternatives is a kind of multi-criteria decision-making MCDM problem. The objective of this paper is to develop an evaluation model based on fuzzy analytic hierarchy process FAHP, grey relational analysis GRA and technique for order performance by similarity to ideal solution TOPSIS. FAHP is used to compute the criteria weights whereas GRA and TOPSIS are combined together and proposed as GRA-TOPSIS for obtaining the final ranking of network alternatives. This study comprises five alternatives such as wireless local area network WLAN, general packet radio service GPRS, universal mobile telecommunication UMTS, code-division multiple-access CDMA, worldwide interoperability for microwave access WiMAX and ten evaluation criteria namely bandwidth, latency, jitter, throughput, bit error rate, packet loss, re-transmission, cost, security and preference to select the appropriate network.

Performance evaluation of MADM-based methods for network selection in a multimedia wireless environment

As mobile devices have become more affordable, easy to use and powerful, the number of mobile users and their bandwidth demands have experienced a significant growth. Considering the rising popularity of power hungry applications (e.g., multimedia), battery power capacity is an important concern--as upgrades are not keeping up with the advances in other technologies (e.g., central processing unit and memory). Mobile users now demand better power and battery management techniques to prolong their mobile battery performance. This, together with the need for green information communications technology, provides motivation for researchers to develop energy efficient techniques to reduce the power consumption in next-generation wireless networks while meeting user's quality expectations. This paper conducts a realistic performance evaluation of a number of widely used multi attribute decision making (MADM)-based methods for network selection that aim at keeping the mobile users Always Best Connected anywhere and anytime. The main trade-off parameters considered include energy efficiency and user perceived quality levels for multimedia streaming. The energy consumption is modeled using real experimental results for an android mobile device. Similarly, the multimedia quality function was modeled using real user data, combined with a qualitative study to determine the resulting mean opinion scores. The performance analysis shows that the weighted multiplicative method (MEW) finds a better energy-quality trade-off for users in a heterogeneous wireless environment in comparison with three other MADM solutions.

A user-centric game selection model based on user preferences for the selection of the best heterogeneous wireless network

Next-generation wireless networks offer Internet connection through various technologies anytime and anywhere. The selection of an optimal technology from these available technologies is essential to guarantee user mobility and service continuity in a heterogeneous wireless environment. This paper proposes a new network selection model which is based on the integration of simple additive weighting (SAW) method in the framework of trading market non-cooperative game theory and the analytic hierarchy process (AHP) method was utilized to estimate the weights of the parameters that affect the network selection process. The proposed solution enables the mobile user to negotiate with competing networks by providing the user preference to be considered for the network selection process. The proposed solution is analyzed and tested through simulations. The results show the efficiency of proposed method which is able to optimize the user’s satisfaction.

Optimized Network Selection Using Aggregate Utility Function in Heterogeneous Wireless Networks

To provide global connectivity with high speed and high quality at any place and any time is now becoming a reality due to the integration and co-ordination of different Radio Access Technologies(RAT) such as Worldwide Interoperability for Microwave Access (WiMAX), Universal mobile Telecommunication Systems (UMTS), Wireless Local Area network (WLAN) and Long Term Evolution (LTE).Such a diversity of networks offers different choices in terms of bandwidth, security, cost, latency and the coverage area for the mobile user. For such a heterogeneous wireless environment, it is important to design an intelligent handover algorithm which selects the optimal target network. The existing works do not consider the interdependence between the criteria and the use of application QoS in weight calculation during network evaluation process. To address this issue, an appropriate multicriteria network selection algorithm based on multiplicative weighted utility function is proposed to provide complete solution for seamless connectivity in heterogeneous environment based on network conditions, application QoS, Mobile Terminal (MT) battery level and user preferences. MATLAB based simulations are conducted to highlight the effectiveness of proposed scheme and simulation results confirm that the proposed scheme selects the best suitable network for both Real-Time (RT) and Non- Real Time (NRT) applications while achieving optimization between QoS, cost and energy consumption. The Cobb-Douglas based user satisfaction degree is also estimated to verify whether the selected network maximizes the end user satisfaction for the offered service.

Analysis of frequency domain frame detection and synchronization in OQAM-OFDM systems

For future communication systems, filter bank multicarrier schemes offer the flexibility to increase spectrum utilization in heterogeneous wireless environments by good separation of signals in the frequency domain. To fully exploit this property for frame detection and synchronization, the advantage of the filter bank should be taken at the receiver side. In this work, the concept of frequency domain processing for frame detection and synchronization is analyzed and a suitable preamble design as well as corresponding estimation algorithms is discussed. The theoretical performance of the detection and estimation schemes is derived and compared with simulation-based assessments. The results show that, even though the frequency domain algorithms are sensitive to carrier frequency offsets, satisfactory frame detection and synchronization can be achieved in the frequency domain. In comparison to time domain synchronization methods, the computational complexity increases; however, enhanced robustness in shared spectrum access scenarios is gained in case the described frequency domain approach is utilized.

A Coalitional Game Based Dynamic Spectrum Sensing Scheme

. In this paper, to help cognitive users conduct fair and efficient spectrum sensing in the heterogeneous wireless environments, a coalitional game based spectrum sensing scheme is proposed. The method of calculating the basic parameters of spectrum sensing is introduced at first, and then the spectrum sensing problem is modeled as a coalitional game with non-transferable utility. A coalition is built with Pareto optimality satisfied, and its procedure is described in details. Simulation results have shown that the proposed scheme is both feasible and effective.

Network Selection Based on Weight Estimation of QoS Parameters in Heterogeneous Wireless Multimedia Networks

Network selection in a heterogeneous wireless environment is a major challenge to ensue seamless mobility across different radio air interfaces. To provide the desired quality of service for a give...

Exploring network selection techniques for multicast groups in heterogeneous wireless environments

Purpose Coexistence of various wireless access networks and the ability of mobile terminals to switch between them make an optimal selection of serving networks for multicast groups a challenging problem. Since optimal network selection requires large dimensions of data to be collected from several network locations and sent between several network components, the scalability can easily become a bottleneck in large-scale systems. Therefore, reducing data exchange within heterogeneous wireless networks is important. The paper aims to discuss these issues.

Vertical Handover Solutions Over LTE-Advanced Wireless Networks: An Overview

The convergence of multitude radio access networks forming a cluster of seamless heterogeneous wireless environment has made the wireless communication industry meet the paradigm of always best connected, where various mobile devices are able to access numerous types of applications and services. However, achieving such landmarks could not be possible without difficulties which this paper tries to highlight some of the technical challenges underlying seamless vertical handover. It provides a general overview of the mobility management process including a brief on multi-homing mobility protocol and focuses on vertical handover decision making techniques, hi ghlighting some radio interface standar and analysed some handover approaches. The paper proposes fast intelligent inter-layer network selection as a new handover approach to select the best network among the candidate networks, where Quality of Service, handover delay and improved data bit rates are set to be achieved.

Available Link Bandwidth Based Network Selection in Multi-access Networks

In a heterogeneous wireless environment, one of the important aspects of seamless communication for ubiquitous computing is the dynamic selection of the best access network. The problem of access network selection has been addressed through various decision methods based on available network information. Available link bandwidth is one of the important information parameters, which can be used as criterion for network selection. In this paper, we consider available bandwidth as a dynamic parameter to select the network in heterogeneous environment. First, we propose a bootstrap approximation based technique to estimate available bandwidth and then utilize it for the selection of the best suitable network in the heterogeneous environment consisting of 2G and 3G standards based wireless networks. The proposed algorithm is implemented in temporal and spatial domains to check its robustness. Estimation time with varying size of files is used as the performance metric. Through numerical results, it is shown that the proposed algorithm gives improved performance as compared to the existing algorithm.

Wireless network access selection scheme for heterogeneous multimedia traffic

Global connectivity, at anyplace and anytime, to provide high-speed, high-quality and reliable communication channels, is now becoming a reality. The credit mainly goes to the recent technological advances in wireless communications, which consist of a wide range of technologies and applications to fulfil the particular needs of end-users in different deployment scenarios (Bluetooth, Wi-Fi, WiMAX and third generation/fourth generation cellular systems). In such a heterogeneous wireless environment, one of the key ingredients to provide efficient ubiquitous computing is the design of intelligent handoff algorithms, which select the optimal target network. This study presents a novel approach for the design and implementation of a multi-criteria vertical handoff decision algorithm for heterogeneous wireless networks to achieve seamless mobility while maximising end-users' satisfaction. Two important modules are designed; the first module estimates the necessity of handoffs and the second module selects the best network as the target of handoff. Several parallel fuzzy logic controllers with reduced rule sets are used, in combination with a fuzzy ranking algorithm, to implement these modules. Simulation results are provided and compared with a benchmark for different evaluation metrics.

Bandwidth Allocation for Vehicle Based Nodes in Heterogeneous Wireless Networks

The present work proposes a communication system to ensure Internet connectivity and network transparency to a group of nodes within a vehicle in heterogeneous wireless networks environment. It considers the integration of three networks. Each vehicle is equipped with multiple cares of addresses corresponding to multiple network interfaces. The proposed scheme provides uninterrupted Internet connectivity to the nodes inside a vehicle while the vehicle moves. It allows communication among a correspondent node and a node inside a vehicle using a suitable care of address for balancing the load among the various wireless access networks. Each network reserves a fraction of the total resource for the processing of handoff session request and new session request depending upon their arrival probability. It entertains a session request only if the desired resource is available which helps to maintain the user satisfaction of the already admitted users in the network to a satisfactory level.

Particle swarm optimization based network selection in heterogeneous wireless environment

Deployment of heterogeneous wireless networks is spreading throughout the world as users want to be connected anytime, anywhere, and anyhow. Meanwhile, users are increasingly interested in multimedia applications such as audio, video streaming and Voice over IP (VoIP), which require strict Quality of Service (QoS) support. Provisioning of Always Best Connected (ABC) network with such constraints is a challenging task. Considering the availability of various access technologies, it is difficult for a network operator to find reliable criteria to select the best network that ensures user satisfaction while reducing multiple network selection. Designing an efficient Network selection algorithm, in this type of environment, is an important research problem. In this paper, we propose a novel network selection algorithm utilizing signal strength, available bit rate, signal to noise ratio, achievable throughput, bit error rate and outage probability metrics as criteria for network selection. The selection metrics are combined with PSO for relative dynamic weight optimization. The proposed algorithm is implemented in a typical heterogeneous environment of EDGE (2.5G) and UMTS (3G). Switching rate of the user between available networks has been used as the performance metric. Moreover, a utility function is used to maintain desired QoS during transition between networks, which is measured in terms of the throughput. It is shown here that PSO based approach yields optimal network selection in heterogeneous wireless environment.

A Utility-Based Rate Allocation of M2M Service in Heterogeneous Wireless Environments

This paper presents a dynamic adaptive machine-to-machine (M2M) service rate allocation scheme for optimum traffic distribution in heterogeneous wireless environments (HWEs). According to the M2M service characteristics, it proposes the utility function, which forms a convex optimization problem that maximizes the utility of M2M service and can be solved by the Lagrange multiplier. The simulation results show the proposed method convergence, and it can achieve load balance with maximized throughput and minimized cost.

Available Bandwidth Estimation for Network Selection in Heterogeneous Environment of WLAN and WiMAX

Always best connected services (ABC) allow multimode mobile terminals to stay connected to the best available networks, at anytime according to user preferences. One of the key aspects in realizing such ABC service is mainly attributed to an effective and dynamic access network selection process. However, most of the previous works consider the access network selection process as a static optimization problem which fails to address the dynamic QoS conditions intrinsic in wireless networks. One of the main challenges remaining is to find an efficient way of obtaining dynamic QoS parameters such as available bandwidth. In this paper, propose a novel dynamic access network selection algorithm capable of adapting to prevailing network conditions. Proposed algorithm is an estimation process where network selection in heterogeneous wireless environment (WiMAX & WLAN) performed using available bandwidth estimation relies on dynamic parameters designed using .net.

I Am 4 VHO: New Approach to Improve Seamless Vertical Handover in Heterogeneous Wireless Networks

Two mechanisms have been proposed independently by IEEE and 3GPP; namely, Media Independent Handover (MIH) and Access Network Discovery and Selection Function (ANDSF), respectively. These mechanisms enable a seamless Vertical Handover (VHO) between the different types of technologies (3GPP and non-3GPP), such as GSM (Global System for Mobile Communication), Wireless Fidelity (Wi- Fi), Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunications System (UMTS) and Long Term Evolution (LTE). In this paper, we overview these mechanisms and show their components, benefits and drawbacks. Then we present our Imperative Alternative MIH for Vertical Handover (I AM 4 VHO) approach based on the approaches that have been studied in the literature with better performance (packet loss and latency), less connection failure (probability of reject sessions), less complexity and more exhaustive for enhancing VHO heterogeneous wireless networks environment.

Utility-based RAT selection optimization in heterogeneous wireless networks

Recent technological advances in wireless networks will enable the realization of an integrated heterogeneous wireless environment consisting of multiple Radio Access Technologies (RATs) within a network provider. One of the most important benefits is that this will allow providers to balance their traffic among their subsystems without compromising on QoS issues. In this paper we focus on the Network Selection problem to allocate terminals to the most appropriate RATs by jointly examining both users’ and providers’ preferences. We introduce three utility-based optimization functions based on the type of application that users request. We then formulate the terminal assignment problem as an optimization problem, which is recognized as NP-hard. We examine both offline and online selection and develop an optimal Branch and Bound (BB) algorithm, a Greedy heuristic, as well as three Strip Packing variations. BB behaves efficiently in both offline and online environments reducing the search procedure, while the proposed heuristics produce results close to the values we get from BB but with very low computational cost.

Network Selection Equilibrium in Heterogeneous Wireless Environment

Service delivery in a heterogeneous wireless environment requires the selection of an optimal access network. In order that users could be always connected through the optimal available network, it is necessary to develop an adequate technique for its selection. This article presents the proposal of suitable network selection technique for heterogeneous wireless environment that is based on TOPSIS method when solving the multiple criteria decision making problems. The radio access networks in this model represent the alternatives, while the network parameters (network conditions, QoS level, security level, cost of service) are considered as the triggering criteria for determining the suitable network. Through simulation studies, we show the potential of entropy based TOPSIS model in optimal network selection process.DOI: http://dx.doi.org/10.5755/j01.eee.19.4.4058