Handover In Heterogeneous Networks Research Articles

Vertical handover in heterogeneous networks using WDWWO algorithm with NN

ABSTRACT In heterogeneous networks, Vertical Handover (VH) plays a vital consequence of customer mobility as they have a high impact on networking performance like delay, throughput and call block probability. Even in the presence of various existing works, VH management exhibit certain drawbacks like method complexity, difficult network modelling and inaccurate handover. Thus, a hybrid methodology is proposed in this work which can provide accurate VH and considerable reduction in working complexity. Here, a combination of Deep Residual Neural (DRN) and Wind-Driven Water Wave Optimisation (WDWWO) is introduced to perform VH. Accurate prediction of Received Signal Strength (RSS) is a difficult task for mobile users while moving from one network to another. In order to tackle this situation, DRN is used with WDWWO based weight optimisation, hence the name Optimised DRN (ODRN). Almost every networking parameters like bandwidth, delay, throughput, velocity, BER, SNR, energy consumption, monetary cost and data traffic are included in ODRN modelling. The proposed work is implemented in NS2 platform and resultant performances like energy consumption, RSS, throughput, packet delivery ratio, packet loss, handover failure rate, algorithm convergence and latency are compared with conventional methods of D-TOPSIS, FIS-ENN and F-AHP.

Vertical Handover Analysis for Randomly Deployed Small Cells in Heterogeneous Networks

In this paper, we analyze vertical handovers in heterogeneous networks. Vertical handovers are an important ramification of user mobility in a heterogeneous wireless network since they directly impact network performance, such as throughput, packet delay, or call blocking probability. However, the study of vertical handovers faces many difficulties when it comes to analysis, including network modeling which is extremely complicated due to topology diversity. To tackle such analytic challenges, we propose a stochastic geometric analysis scheme on user mobility and small cell networks, in order to capture the impacts of different topologies. We derive a theoretical expression for the expected number of handovers that occur and a corresponding approximation. Our analysis shows that the number of vertical handovers is determined as a concave function of small cell radius r when given the small cell density. Via simulations our analysis is verified in various wireless environments.

Improving Modified Grey Relational Method for Vertical Handover in Heterogeneous Networks

With the advent of next-generation wireless network technologies, vertical handover has become indispensable to keep the mobile user always best connected (ABC) in a heterogeneous environment, especially the significant number of multimedia applications that require good quality of service (QoS) for users. To handle this issue, an improvement of modified Grey Relational Analysis (MGRA) to select the Always-Suitable-Connection (ASC) network has been proposed. Then, Fuzzy analytic hierarchy process (FAHP) method has been used to determine the weight of criteria. In order to validate our contribution, the proposed method called E-MGRA has been applied to obtain the ranking of suitable network. Finally, a simulation has been presented to demonstrate the performances of our developed approach to reduce the number of handovers compared to the classical method.

VIKOR MADM Based Optimization Method For Vertical Handover In Heterogeneous Networks

Optimum network selection is one of the major issues for vertical handover in heterogeneous networks so as to provide requisite quality of service (QoS) to the user. In this context, multiple attribute decision-making algorithms provide a promising solution. Normalization process used can play a vital role in selecting the most appropriate network during the handover process.In this work, vector normalized preferred performance based (V-VPP) normalization technique is proposed and applied to MADM based VIKOR algorithm. Performance of the proposed technique is analyzed extensively by varying QoS parameters and weighting methods for different traffic classes in a heterogeneous network The results obtained are compared with the available MAX, MAX-MIN and Vector normalization.The proposed method is also compared with the popular MADM algorithms. Performance of proposed method is quite optimistic in terms of lesser number of handovers, ranking abnormality, selection of appropriate network though with slight increase in handover latency in comparison to the available normalization methods.

A novel model for minimizing unnecessary handover in heterogeneous networks

Over the years, vertical handover necessity estimation has attracted the interest of numerous researchers. Despite the attractive benefits of integrating different wireless platforms, mobile users are confronted with the issue of detrimental handover. This paper uses extensive geometric and probabilistic techniques to develop a realistic and novel model for the coverage area of a wireless local area network (WLAN) cell with an aim to minimize unnecessary handover and handover failure of a mobile node (MN) traversing the WLAN cell from a third-generation network. The dwell time is estimated along with the threshold values to ensure an optimal handover decision by the MN, while the probability of unnecessary handover and probability of handover failure are kept within tolerable bounds. Monte Carlo simulations were carried out to assess the behavior of the proposed and existing models. Simulation results showed that our proposed model is more robust and capable of keeping unnecessary handover probability and handover failure probability closest to a predefined probability benchmark. For model validation, the Nash--Sutcliffe coefficient was used to compute the efficiency of the proposed model, which achieved a value of 98.82{\%} indicating the accuracy of the model.\vs{2mm

WOA-NN: a decision algorithm for vertical handover in heterogeneous networks

The heterogeneous network of a 4th generation not always support better communication and mobility between the Wireless Access Networks. Hence, the vertical handoff is highly necessitated. This paper establishes vertical handover, which is context-aware in a heterogeneous environment with WiMax and WiFi. Successful handover results with the better determination of handover points. So, an Artificial Neural Network-based network model to understand the network characteristics is firstly developed. Under simulated environment, the Received Signal Strength (RSS) of the heterogeneous network is observed to construct the training library. The trained network predicts RSS for resolving the handover points in the heterogeneous network. To ensure precise learning of the neural network about the RSS network characteristics, a renowned Whale Optimization Algorithm (WOA) is developed. The performance of WOA-NN model is compared with the conventional Levenberg–Marquardt-Neural Network, Fire Fly-Neural Network, Particle Swarm Optimization-Neural Network and Grey Wolf Optimization-Neural Network through throughput, handover, predicted RSS and Mean Absolute Error analyses. The predicted RSS of the proposed WOA-NN-based network model seems nearly closer to the actual model, attaining effective handoff.

Modeling and Analyzing the Cross-Tier Handover in Heterogeneous Networks

Denser deployments of heterogeneous networks (HetNets) lead to more frequent handovers, which results in a decline of user experience as well as heavy signaling overheads to the network. Therefore, the study on handover is of great importance especially in dense HetNets. In this paper, we focus on the analysis of cross-tier handover from the macro cell tier to the small cell tier, which shows the highest handover failure rate in current standards and industry studies. Using the stochastic geometry, we propose an analytical model for the cross-tier handover processes in the HetNet. Based on the derived analytical model, the closed-form expressions for the key handover performance metrics, including the handover rate, handover failure rate, and ping-pong rate, are deduced as functions of the base station density, time to trigger and user mobility. Simulation results verify the accuracy of the proposed analytical model and closed-form theoretical analyses, which provide guidance for the deployments of HetNets and corresponding handover strategies.

ARM-FPGA-based platform for reconfigurable wireless communication systems using partial reconfiguration

Today, wireless devices generally feature multiple radio access technologies (LTE, WIFI, WIMAX,...) to handle a rich variety of standards or technologies.These devices should be intelligent and autonomous enough in order to either reach a given level of performance or automatically select the best available wireless technology according to standards availability. On the hardware side, system on chip (SoC) devices integrate processors and field-programmable gate array (FPGA) logic fabrics on the same chip with fast inter-connection. This allows designing software/hardware systems and implementing new techniques and methodologies that greatly improve the performance of communication systems. In these devices, Dynamic partial reconfiguration (DPR) constitutes a well-known technique for reconfiguring only a specific area within the FPGA while other parts continue to operate independently. To evaluate when it is advantageous to perform DPR, adaptive techniques have been proposed. They consist in reconfiguring parts of the system automatically according to specific parameters. In this paper, an intelligent wireless communication system aiming at implementing an adaptive OFDM-based transmitter and performing a vertical handover in heterogeneous networks is presented. An unified physical layer for WIFI-WIMAX networks is also proposed. The system was implemented and tested on a ZedBoard which features a Xilinx Zynq-7000-SoC. The performance of the system is described, and simulation results are presented in order to validate the proposed architecture.

Genetic Based Approach to Optimize the Vertical Handover Performance Among Heterogeneous Network

Mobile terminals typically can be connected to multiple wireless networks that offer different degrees of suitability for different classes of service. A genetic algorithm (GA) - based on a supervised approach - is used to assess the likelihood of a successful handover in heterogeneous networks to increase capacity and network performance. Traditional handoff schemes are prone to ping-pong and corner effects, and the development of an optimized handover scheme for a seamless, faster and less energy-consuming handover decision is a challenge. In order to ensure service continuity and to maintain the promising QoS, the handover decision should be made appropriately. The most general criteria for handover is the received signal strength, which is not sufficient in advanced networks. The GA scheme can effectively optimize the soft handoff decision by using the best-fit network for the mobile terminal (MT), taking into account the quality of service requirements (QoS), the network parameters, and the user preference for the cost of the various connection points for the MT is selected. The mathematical model-based approach to vertical handoff prediction involves a well-defined objective function taking into account signal strength, user equipment speed, load and cost per user bandwidth. The system performance can be improved according to the user settings by adjusting the weights in the defined objective function. Due to the high bandwidth and easy networking, the system consider the wireless access standards: UMTS, Wi-Fi, LTE and Wimax. The decision problem is formulated as several objective optimization problems and simulated using a monitored genetic algorithm. The simulation result shows that the number of handovers can be minimized when using optimized network parameter values.

Cross layer architecture with integrated MIH in heterogeneous wireless networks

Progress in new radio technologies and raise in users’ demands are motivating the deployment of a wide array of wireless networks, ranging from Wireless Local Area Network (WLAN), to fifth generation (5G). These heterogeneous Radio Access Technologies (RATs) are expected to be integrated together to provide mobile users QoS guarantees. Heterogeneous Wireless Networks (HWNs) provide an opportunity for developers to design efficient framework to satisfy stringent QoS requirement. This integration of different networks results in performance degradation when handovers occur during a mobility event. As a result, the effective mobility management protocols are required to support ubiquitous network access by providing seamless handover. In IEEE 802.21 standard, the framework Media Independent Handover (MIH) is proposed to facilitate handover in heterogeneous networks with measurements and triggers from link layers. This article emphasizes in relationship between the MIH framework and different modules in the MAC layer. In order to guarantee the QoS for different service flows with diverse QoS requirements, we propose to design new cross-layer based designs architecture to provide a combined solution for vertical and horizontal handover based on IEEE 802.21 MIH. We propose new modules in different layers and new primitives to facilitate the communication. Conducted simulations demonstrate the effectiveness of the proposed approaches. We evaluate the proposed architecture using a scheduling algorithm which improves system performance as shown by the results presented of a comparative analysis with the NSA (New Scheduling Algorithm) and EDF (Earliest Deadline First) schemes.

Upper Bound Analysis of the Handover Performance in HetNets

Handover in heterogeneous networks (HetNets) is an interesting research challenge that has attracted considerable attention in recent years, producing a variety of handover schemes that are difficult to compare because they differ in the considered assumptions and target user/network utility functions. Therefore, how much room is left for further optimization is quite unclear. In this letter, we propose a framework to derive an upper bound for the performance of handover in HetNets that can be used as a benchmark to compare different practical handover schemes. The approach computes the optimal handover strategy as a function of the user’s speed, cell size, and load conditions, under the ideal assumption of non-causal knowledge of the channels from terminal and base stations. The proposed framework is then used to provide a comparative performance analysis among some existing handover schemes.

Vertical handover decision algorithm in heterogeneous wireless networks

With the recent progress in the area of cellular communication the issue of inter cells handover without dropping an ongoing connection with the base station has arisen. In this paper, the focus is on the performance of vertical handover. Various proposed interconnection architectures for vertical handover in heterogeneous networks were studied. Two different algorithms to make the decision on when and to which network perform a handover were considered. In the first of them the decision is based on the received signal strength (RSS). In the second one a fuzzy logic system that uses RSS, bandwidth, battery power and packet loss as the input parameters is proposed. The simulation results show that the algorithm based on fuzzy logic leads to a reduction of the number of handovers and a minimisation of the power consumption as compared to the first algorithm used here and the existing algorithms.

Adaptive probe-based congestion-aware handover procedure using SIP protocol

Wireless technologies have evolved very rapidly in recent years. In the future, operators will need to enable users to use communication services independently of access technologies, so they will have to support seamless handovers in heterogeneous networks. In this paper we present a novel adaptive congestion aware SIP based procedure for handover in heterogeneous networks. In the proposed algorithm the handover decision is based in addition to signal strength, also on target network congestion status, which is tested during the conversation. As SIP protocol was used, the proposed procedure is independent of access technologies. For performance evaluation of proposed procedure we developed a purpose‑built simulation model. The results show that the use of the proposed adaptive procedure significantly improves the QoE of VoIP users, compared to reference scenario, in which only signal strength was used as the trigger for handover decision.

Survey and Analysis of Integrating PMIPv6 and MIH Mobility Management Approaches for Heterogeneous Wireless Networks

The deployment of different types of wireless technologies led to additional challenges to the issue of mobility management in next generation wireless networks. In addition to the regular movement of the mobile users in a heterogeneous environment, users' demand for more real time services results in more handover complexity. Even though the network-based proxy mobile IPv6 (PMIPv6) is considered a favorable protocol for mobility management and the IEEE 802.21 media independent handover (MIH) framework designed to support seamless handover in heterogeneous networks, these protocols, each one separately, fails to provide seamless handover procedure for time sensitive applications in heterogeneous wireless networks. Therefore, several works have been done to integrate the network-based PMIPv6 with the capabilities of MIH to obtain an enhanced solution. In this paper, we reviewed the PMIPv6 and MIH integration schemes in the literature and we categorized them into six schemes based on the signals or network entities modifications. Also, we provide a comparative analytical evaluation for handover procedures of these schemes in terms of signaling cost, total handover latency, and packet loss. Based on the features and analysis, the integration with network is the best solution that to be considered.

Hysteresis Margin and Load Balancing for Handover in Heterogeneous Network

Hysteresis Margin and Load Balancing for Handover in Heterogeneous Network

AN INTELLIGENT VERTICAL HANDOVER DECISION ALGORITHM FOR WIRELESS HETEROGENEOUS NETWORKS

The Next Generation Wireless Networks (NGWN) should be compatible with other communication technologies to offer the best connectivity to the mobile terminal which can access any IP based servi ces at any time from any network without the knowledge of its user. It requires an intelligent vertical hando ver decision making algorithm to migrate between technologies that enable seamless mobility, always best connection and minimal terminal power consumption. Currently existing decision engines are simple, proprietary and its handover is only based on the r eceived signal strength which has been proven unintelligent. The proposed decision algorithm gain s intelligence by combining fuzzy logic system to handle imprecise data, multiple attribute decision making to handle multiple attributes for decision m aking and context aware strategies to reduce unnecessary handover. The proposed intelligent decision algorit hm detects new network which offers best connectivity than current network and does authentication and mobile IP registration before making the handover; thereby reducing the packet loss to ensure high qua lity of service. This algorithm is capable of forwarding data packets to appropriate attachment point to maximize battery lifetime and also to maintain load balancing. The performance analysis shows that the proposed algorithm efficiently uses the network res ources by switching between 3G and Wi-Fi under the different RF environmental conditions to offer best connectivity with minimal service cost to the user s. It is observed that average handover delay for the experi ment is 30-40ms and the integration of cellular net work with WLAN using the proposed intelligent decision algorithm reduces the call dropping rate (<0.006) an d call blocking probability (<0.00607) as well as unn ecessary handover in heterogeneous networks.

Simulation of Performance Execution Procedure to Improve Seamless Vertical Handover in Heterogeneous Networks

One challenge of wireless networks integration is the ubiquitous wireless access abilities which provide the seamless handover for any moving communication device between different types of technologies (3GPP and non-3GPP) such as Global System for Mobile Communication (GSM), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunications System (UMTS) and Long Term Evolution (LTE). This challenge is important as Mobile Users (MUs) are becoming increasingly demanding for services regardless of technological complexities associated with it. To fulfill these requirements for seamless Vertical Handover (VHO) two main interworking architectures have been proposed by European Telecommunication Standards Institute (ETSI) for integration between different types of technologies; namely, loose and tight coupling. On the other hand, Media Independent Handover IEEE 802.21 (MIH) is a framework which has been proposed by IEEE Group to provide seamless VHO between the aforementioned technologies by utilizing these interworking architectures to facilitate and complement their works. The paper presents the design and the simulation of a Mobile IPv4 (MIPv4) based procedure for loose coupling architecture with MIH to optimize performance in heterogeneous wireless networks. The simulation results show that the proposed procedure provides seamless VHO with minimal latency and zero packet loss ratio.

Design and analysis of an IEEE 802.21-based mobility management architecture: a context-aware approach

Broadband wireless technologies will soon become an integral part of daily life. In this paper we present the design rationale of a context-aware mobility management architecture for seamless handover in heterogeneous networks. Our proposal is a new cross-layer and interactive approach to seamless handover of users and their services. We present a simple though effective analytical model in typical deployment scenarios in heterogeneous networks with the use of the IEEE Media Independent Handover services. Such analytical model is used to evaluate the resulting handover delay when deploying common mobility protocols in our architecture, such as Mobile IP, Hierarchical MIP, and Proxy MIP.

Intelligent cell selection satisfying user requirements for inter-system handover in heterogeneous networks

Cell selection for inter-system handover in heterogeneous networks is one of the key issues in 4G cellular networks to maintain constant or near-constant QoS (Quality of Service) where cells may be overloaded. There exist many proposals in literature on cell selection methods for intra-system handovers and inter-system handovers. We propose an intelligent cell selection scheme for inter-system handovers in heterogeneous networks that satisfies user requirements as well as system requirements. The proposed scheme uses uncertain parameters such as user system preference, communication cost, mobile speed, transmission delay, packet loss, and cell loads in the decision process utilizing the aggregation functions in fuzzy set theory. Contrary to many existing schemes which consider only either system parameters or user requirements, the proposed scheme considers both. The proposed scheme hierarchically analyzes the relative value of cell selection parameters based on the current state of heterogeneous networks, the speed of mobile terminals, and the change in QoS. Then, it focuses on the adaptation of relative importance values for each cell selection parameter. Computer simulation results show that our proposed scheme provides systems and users with much better performance compared to existing schemes.

Soft Multi-Criteria Decision Algorithm for Vertical Handover in Heterogeneous Networks

Choosing or switching between heterogeneous networks according to the highest performance in terms of quality of service is largely inefficient in vertical handover. In fact a service may have unstable performance and require highly frequent vertical handover procedures. In this paper we consider the impact of statistical fluctuations of performance parameters (decision under risk) and propose a soft algorithm that exploits the statistical knowledge in order to reduce outage probability.