Heterogeneous Wireless Access Networks Research Articles

Fast Vertical Handover Algorithm for Vehicular Communication: A Holistic Approach

Next generation vehicular communication environment will consist of heterogeneous radio access networks (RAN). For seamless connectivity, vertical handover is a mandatory requirement. A novel context aware vertical handover algorithm is presented here. TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), which is a multi criteria decision making (MCDM) tool, is used for the development of algorithm and MATLAB/SIMULINK is used as simulation platform. The optimum network is selected, based on multiple factors such as network traffic load, velocity of mobile station, data rate, usage cost and initial delay of network, among the available networks such as WiMax, WLAN and UMTS. This algorithm has been tested by simulating a virtual road traffic scenario. Variations in optimum RAN selection with vehicle speed keeping network traffic load constant and RAN selection with network traffic load keeping vehicle speed constant are shown graphically. The proposed algorithm is very simple yet powerful compared to the existing VHO algorithms and hence requires less execution time. Index Terms— ITS, Vertical handover (VHO), MCDM, TOPSIS, V2V and V2I.

Mapping of QoS between UMTS and WiMAX in Tight Coupling Heterogeneous Wireless Network

G network or Heterogeneous wireless access network will integrate existing wireless access technologies (e.g. 2G, 3G, WiMAX, WLAN, etc…) in order to provide, transparently, end- users with the service through connecting their mobile devices at any time to the best available radio network. In that context, mapping the QoS classes between these different access networks becomes a big challenge. In this paper, we propose a method of mapping between the CoS of UMTS and QoS categories of WiMAX in a tight coupling architecture of Heterogeneous Wireless Access Network (HWAN).

Game-theoretic rate allocation with balanced traffic in collaborative transmission over heterogeneous wireless access networks

To balance the traffic in high-speed collaborative transmission, the static rate allocation problem over heterogeneous wireless access networks is formulated in a weighted bargaining game framework, where the heterogeneity of transmission capability of different networks is taken into account. The weights in the framework, which are used to describe the bargaining power of the bargaining game, are determined by the available bit rates of different networks. With the maximised throughput gain as the optimal objective, the closed form of the Nash bargaining solution is derived with the Lagrange multipliers method. Simulation results demonstrate that the presented framework is more efficient with completely balanced traffic so as to make full use of the heterogeneous network resource and prevent network saturation as much as possible.

A Robust Mobile Video Streaming in Heterogeneous Emerging Wireless Systems

With the rapid development of heterogeneous emerging wireless technologies and numerous types of mobile devices, the need to support robust mobile video streaming based on the seamless handover in Future Internet is growing. To support the seamless handover, several IP-based mobility management protocols such as Mobile IPv6 (MIPv6), fast handover for the MIPv6 (FMIPv6), Hierarchical MIPv6 (HMIPv6) and Proxy Mobile IPv6 (PMIPv6) were developed. However, MIPv6 depreciates the Quality-of-Service (QoS) and FMIPv6 is not robust for the video services in heterogeneous emerging wireless networks when the Mobile Node (MN) may move to another visited network in contrast with its anticipation. In Future Internet, the possibility of mobile video service failure is more increased because mobile users consisting of multiple wireless network interfaces (WNICs) can frequently change the access networks according to their mobility in heterogeneous wireless access networks such as 3Generation (3G), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMax) and Bluetooth co-existed. And in this environment, seamless mobility is coupled according to user preferences, enabling mobile users to be “Always Best Connected” (ABC) so that Quality of Experience is optimised and maintained. Even though HMIPv6 and PMIPv6 are proposed for the location management, handover latency enhancement, they still have limit of local mobility region. In this paper, we propose a robust mobile video streaming in Heterogeneous Emerging Wireless Systems. In the proposed scheme, the MN selects the best -according to an appropriate metric- wireless technology for a robust video streaming service among all wireless technologies by reducing the handover latency and initiation time when handover may fail. Through performance evaluation, we show that our scheme provides more robust mechanism than other schemes.

Challenges of Future R&D in Mobile Communications

This paper provides a survey for the main challenges of future research and development (R&D) for next generation mobile networks (NGNs). It addresses software and hardware re- configurability with focus on reconfigurable coupling and interworking amongst heterogeneous wireless access networks. It also explores the promising technologies for NGNs such as nanotechnology, cloud computing and texting by thinking. The paper then highlights the challenging research areas for enhancing network performance and affordability beginning with All IP network and security issues, Vehicular Ad Hoc Networks (VANET) and the necessity of high data rates at cell edges. Investigating the viability of cooperative networks and one unified global standard for NGNs, the paper analyzes macro- diversity and advanced multi-cell coordination for mitigating inter-cell interference. Direct device-to-device communication, global coverage using satellites and high-altitude platforms are presented as possible evolution paths for space roaming and extending NGN' radio-access. Finally, the paper inspects the most developing applications for NGNs such as World-Wide Wireless Web (WWWW), machine-type communication, wireless sensor networks (WSNs), e-healthcare systems and wearable devices with AI capabilities.

Simple harmonic oscillator immune optimization algorithm for solving vertical handoff decision problem in heterogeneous wireless network

In heterogeneous wireless network environment, wireless local area network (WLAN) are 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 could occur frequently, with regard to vertical handoff performance, there is a critical need 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, propose an artificial simple harmonic oscillator immune algorithm-based vertical handoff decision scheme, and perform the simulation experiments to validate proposed solution. Experimental result shows that the proposed solution, compared with literature solutions, can not only balance the overall load among all networks but also increase the collective battery lifetime of mobile terminals, and has the advantage of good application value.

Smart interface switching for energy efficient vertical handovers in ns-2

The growing presence of concurrent heterogeneous wireless access networks, together with the increasing service demands from the end-users, require re-thinking of current access selection polices and appropriate management mechanisms, namely concerning quality of service, energy efficiency, etc. The recent IEEE 802.21 standard introduces link layer intelligence as well as related network information to upper layers in order to optimise handovers between networks of different technologies, such as WiMAX, Wi-Fi and 3GPP. With the massification of mobile terminals with multiple wireless interfaces it is important to efficiently manage those interfaces not only to appropriately provide the requested services to the user, but also to do that in an energy efficient way in order to allow higher mobility to the user by extending the battery life of its terminal. The study the IEEE 802.21 standard is briefly introduced, presented in the signalling in a handover between WiMAX and Wi-Fi, and exploited through an implementation in ns-2 introducing a simple, but effective, energy-saving approach.

Joint resource allocation for WLAN&WCDMA integrated networks based on spectral bandwidth mapping

Next wireless network aims to integrate heterogeneous wireless access networks by sharing wireless resource. The spectral bandwidth mapping concept is proposed to uniformly describe the resource in heterogeneous wireless networks. The resources of codes and power levels in WCDMA system as well as statistical time slots in WLAN are mapped into equivalent bandwidth which can be allocated in different networks and layers. The equivalent bandwidth is jointly distributed in call admission and vertical handoff control process in an integrated WLAN/WCDMA system to optimize the network utility and guarantee the heterogeneous QoS required by calls. Numerical results show that, when the incoming traffic is moderate, the proposed scheme could receive 5%–10% increase of system revenue compared to the MDP based algorithms.

듀얼스택 단말을 지원하는 차세대 이동성 지원 기술 연구

본 논문에서는 망 기반의 IP 이동성 지원 기술인 AIMS 기술을 기반으로 IPv4와 IPv6가 혼재된 망 환경에서 이동 단말에 대한 끊김 없는 이동성을 지원하는 AIMS-DS 기술을 제안하였다. 제안된 AIMS-DS 기술은 IPv4와 IPv6 프로토콜을 모두 지원하는 듀얼스택 단말에 대하여 IPv4와 IPv6 홈 주소들에 대한 이동성 지원 방안을 제안함으로써, IPv4와 IPv6가 혼재되어 공존하는 과도기적인 망 환경에서 양단간 끊김 없는 이동성 서비스를 제공할 수 있다. 본 논문에서는 액세스 망과 코어 망의 IP 버전에 따른 4가지 경우에 대하여 양단간 패킷 전달 지연 시간과 핸드오버 지연시간에 대하여 AIMS-DS에 대한 성능 분석을 수행하였다. In this paper, we propose a network-based IP mobility management scheme, called Access Independent Mobile Service with IPv4/IPv6 Dual Stack (AIMS-DS), which can provide high-quality multimedia services to IPv4/IPv6 dual-stack mobile nodes (MNs) without any interruption over various wireless/wired access networks. The proposed scheme provides an MN with a fast and reliable mobility service among heterogeneous wireless access networks through the network-based control, the complete separation method of control and data plane, the cross-layer (layer2 and layer3) interworking method for handover control acceleration, etc, In addition, the proposed AIMS-DS can provide seamless mobility service to an MN under the environments of IPv4/IPv6 coexisting networks through the home address mobility support and transport network support. Through performance evaluation with computer simulations, we have shown the superiority of the proposed AIMS-DS in terms of handover latency, packet 1085 and packet delivery latency.

A scalable network-based mobility management framework in heterogeneous IP-based networks

This paper proposes a mobility management scheme to provide a mobile node with high-quality handovers among heterogeneous wireless access networks. The proposed scheme employs a signaling architecture to support fast and reliable delivery of control messages by separating a control plane from a data transport plane in the core network. The proposed scheme is based on the network-based mobility management framework which requires the minimum modifications on terminal devices. With interaction between Layers 2 and 3, the proposed scheme accelerates the handover control procedures. It also enables a mobile subscriber to select a target network for a vertical handover with consideration of not only wireless signal strength but also user preference and quality-of-service status. The proposed scheme addresses the well-known problems of the Mobile IP-based approaches, triangular routing and bottleneck at the home agent, since it establishes a data tunnel for a mobile node along the shortest path between two different access networks. The simulation and experimental results indicate that our scheme provisions more efficient performance than the existing approaches in terms of handover latency, data packet loss, data delivery latency and load balancing.

Network Selection in Heterogeneous Wireless Networks based on Fuzzy Multiple Criteria Decision Making

Next generation wireless networks are expected to exhibit heterogeneity in terms of wireless access technologies, services and application requirements. These heterogeneous wireless access networks consist of the integration of various wireless networks especially Wi-Fi (WLAN), Wi-Max and 3G/B3G cellular networks. One of the challenging problems is to choose the optimal network depending upon the type of the demanding application. Vertical handoff occurs when a mobile terminal decides to switch to the selected network from the current network. This paper mainly deals with a network selection algorithm based on Fuzzy Multiple Attribute Decision Making. The algorithm considers the factors of Received Signal Strength(RSS), Monetary cost(C), Band Width (BW), Velocity (V) and user preference (P). It finds the Network selection function (NSF) that measures the efficiency in utilizing radio resources by handing off to a particular network. The network that provides highest NSF is selected as the best network to hand off from the current access network.

A constrained MDP-based vertical handoff decision algorithm for 4G heterogeneous wireless networks

The 4th generation wireless communication systems aim to provide users with the convenience of seamless roaming among heterogeneous wireless access networks. To achieve this goal, the support of vertical handoff is important in mobility management. This paper focuses on the vertical handoff decision algorithm, which determines the criteria under which vertical handoff should be performed. The problem is formulated as a constrained Markov decision process. The objective is to maximize the expected total reward of a connection subject to the expected total access cost constraint. In our model, a benefit function is used to assess the quality of the connection, and a penalty function is used to model the signaling incurred and call dropping. The user's velocity and location information are also considered when making handoff decisions. The policy iteration and Q-learning algorithms are employed to determine the optimal policy. Structural results on the optimal vertical handoff policy are derived by using the concept of supermodularity. We show that the optimal policy is a threshold policy in bandwidth, delay, and velocity. Numerical results show that our proposed vertical handoff decision algorithm outperforms other decision schemes in a wide range of conditions such as variations on connection duration, user's velocity, user's budget, traffic type, signaling cost, and monetary access cost.

Handover approaches for seamless mobility management in next generation wireless networks

ABSTRACTNext generation wireless networks (NGWN) will be an integration of heterogeneous wireless access networks that will interwork over an IP‐based infrastructure. This all‐IP vision has led to the development of handover mechanisms to support seamless mobility for active network services among the different interworking wireless networks in order to ensure network access ubiquity in NGWN. These handover mechanisms need to ensure that mobile devices continue to receive ongoing communication without any noticeable disruption during handover events among the heterogeneous networks. This paper gives a qualitative and quantitative review of current handover approaches of IP mobility management protocols for NGWN with an objective to introduce a new way of further optimizing the handover performance. In particular, the paper focuses on handover approaches of mobile IPv6 (MIPv6) based mobility management protocols. Thus, the need, benefits, and limitations of these handover approaches are explored. Thereafter, dynamic handover coordination is introduced as a new viable solution that exploits the benefits and mitigates the limitations of these handover approaches hence improving handover performance in terms of handover delay, packet loss, and signaling overhead. Copyright © 2011 John Wiley & Sons, Ltd.

RSS based Vertical Handoff algorithms for Heterogeneous wireless networks - A Review

Heterogeneous networks are integrated in fourth generation. To have seamless communication and mobility between these heterogeneous wireless access networks, support of vertical handoff is required. Vertical handover is convergence of heterogeneous networks for e.g.:- handover between WLAN and cellular networks. In this paper, three algorithms on RSS based vertical handoff are discussed. First, algorithm is adaptive lifetime based vertical handoff, which combines RSS and estimated lifetime (expected duration after which the MT will be able to maintain its connection with WLAN) to decide the vertical handover. Second algorithm, is based on dynamic RSS threshold which is more suitable for handover from WLAN to 3G network. Third algorithm is a traveling distance prediction method, which works well for WLAN to cellular networks and vice versa. This avoids unnecessary handoff and also minimizes failure robability.

Detection of Traffic Congestion Based on Link-Level Metrics in IEEE 802.11 Networks

In this paper, we address adaptive link switching over heterogeneous wireless access networks including IEEE 802.11. When an IEEE 802.11 link is congested, the transmission link of a terminal with multi-RATs (radio access technologies) is switched to another radio access systems. To this end, we propose link-level metrics of LC (link cost) and AC (access cost) for quantifying TCP congestion over IEEE 802.11 networks. The proposed metric can be easily measured at a local wireless terminal, and that enables each multi-RAT terminal to work in a distributed way. Through various indoor and outdoor experiments using a test-bed system, we verify that the proposed link level metrics are good indicators of TCP traffic congestion. Experimental results show that the proposed metrics can detect congestion occurrence quickly, and avoid the TCP throughput degradation of other neighboring terminals, when they are used for transmission link switching.

A QoS-based dynamic pricing approach for services provisioning in heterogeneous wireless access networks

In this paper we propose a simple QoS-based dynamic pricing approach for services provisioning in a heterogeneous wireless access network environment which attempts to increase user’s satisfaction level by firstly, maximizing the provided QoS level, and secondly, by applying dynamic pricing strategies according to the QoS. These strategies will allow service providers to maximize their profits. Simulation results demonstrate that the proposed dynamic pricing approach benefits both users and wireless service providers (WSPs). Results also suggest that users have better overall satisfaction due to a better QoS level and fairer prices. The analysis shows that our proposed pricing approach contributes to an increase in WSPs profits compared to the application of the flat-rate pricing model in a competitive market-model.

Predictive Dynamic Uplink /Downlink Resource Reservation for Vertical Handoff Optimization in 4G Networks

The fourth generation of mobile wireless networks (4G) is expected to be the most promising architecture for QoS provision due to its scalability, convenience for mobility support and capability of interworking heterogeneous radio access networks, which ensure both session continuity and QoS support. One major design issue of the 4G is the support of optimized handoff functionalities. More specifically, total disruption during a handoff should be minimized and its complexity hidden to end users. In this regard, the authors focus on developing new dynamic predictive resource reservation schemes in 4G for both uplink and downlink to maximize handoff success probability. The paper illustrates how to reserve radio resources according to future mobile terminal location expressed in a probabilistic way, to load conditions or target Base Station/Access point BS/AP and to the specificity of the data structure of each access network. Different resource reservation algorithms are devised. The objective is to efficiently utilize wireless radio resources, enhance the handoff performances and improve system performance.

Design and assessment of functional architecture for optimized spectrum and radio resource management in heterogeneous wireless networks

AbstractThe emerging and future radio landscape will consist of heterogeneous wireless networks, operating in the framework of diverse cooperative associations of network operators, for accommodation of the demands of users with multimode and/or multihoming enabled terminals. In this context, the optimized spectrum and radio resource utilization will be key factors for the accomplishment of the goals of both users and operators, namely the satisfaction of users' needs and the augmentation of operators' profits. The IEEE P1900.4 standardization group is working towards specifying architectures and functions that will enable network‐terminal distributed decision making for optimized radio resource usage in such heterogeneous wireless access networks. In alignment with the recently standardized P1900.4 management architecture, in this paper we (a) propose a functional architecture for the management and optimization of spectrum and radio resource utilization in heterogeneous wireless environments, (b) give a thorough description of the information that needs to be conveyed on the external interfaces of the proposed architecture, and (c) set up an experimentation platform and conduct indicative scenarios for both the demonstration and performance assessment of the proposed architecture. The assessment results show satisfactory behavior in terms of induced management signaling loads and time delays, that is equivalent to minimal intervention into the real network operation. Copyright © 2009 John Wiley & Sons, Ltd.

Vehicular telematics over heterogeneous wireless networks: A survey

This article presents a survey on vehicular telematics over heterogeneous wireless networks. An advanced heterogeneous vehicular network (AHVN) architecture is outlined which uses multiple access technologies and multiple radios in a collaborative manner. The challenges in designing the essential functional components of AHVN and the corresponding protocols (for radio link control, routing, congestion control, security and privacy, and application development) are discussed and the related work in the literature are reviewed. The open research challenges and several avenues for future research on vehicular telematics over heterogeneous wireless access networks are outlined.

Remote patient monitoring service using heterogeneous wireless access networks: architecture and optimization

Remote patient monitoring is an eHealth service, which is used to collect and transfer biosignal data from the patients to the eHealth service provider (e.g., healthcare center). A heterogeneous wireless access-based remote patient monitoring system is presented in which multiple wireless technologies are integrated to support continuous biosignal monitoring in presence of patient mobility. A patient-attached monitoring device with a heterogeneous wireless transceiver collects biosignal data from the sensors and transmits the data through the radio access network (RAN) to the eHealth service provider. In this system, the eHealth service provider reserves wireless bandwidth (or connections) from a network service provider in a proactive manner as well as in an on-demand basis. To determine the optimal number of connections to be reserved pro-actively so that the network access cost is minimized, a stochastic programming problem is formulated considering the randomness of service demand due to the mobility of the patients. Since different biosignal data can have different quality-of-service (QoS) requirements, traffic scheduling is used in the patient-attached device which determines whether to transmit and what to transmit over an available wireless connection. To make the optimal scheduling decision, an optimization problem is formulated as a constrained Markov decision process (CMDP). The objective of this formulation is to minimize the connection cost. The proposed system architecture and the optimization formulations will be useful for the eHealth service provider to provide flexible and cost-effective monitoring service to remote/mobile patients.