Seamless Handoff Research Articles

RSVP Extensions for Seamless Handoff in Heterogeneous WLAN/WiMAX Networks

Providing a seamless handoff for QoS connections in heterogeneous wireless local networks (WLANs) and worldwide interoperability for microwave access (WiMAX) networks is crucial. The handoff delay is one of the troublesome issues that users are facing in the heterogeneous WLAN/WiMAX networks. Many mobile users still cannot obtain the network resources they need when employing real-time services such as voices, video conferences, video IP phones, and so forth while a handoff occurs, which usually causes a serious delay or even a break of the link. Resource ReSerVation Protocol (RSVP) can provide the necessary QoS because of its bandwidth guaranteed capacity. In this paper, an RSVP extension scheme is proposed for seamless handoffs in the heterogeneous WLAN/WiMAX networks. The proposed scheme is based on QoS aware mobility architecture to guarantee a certain degree of QoS. The network selection is initiated by the mobility of the mobile station (MS) and a pre-handoff is performed based on received signal strength (RSS). Simulation results show that the proposed scheme outperforms the other two schemes.

Practical secure and fast handoff framework for pervasive Wi‐Fi access

Seamless handoff is crucial for providing pervasive wireless access especially to support time-sensitive applications in 802.11i security enhanced WLAN, but it introduces large authentication delay to provide advanced security during a handoff. In order to reduce the authentication delay, the IEEE 802.11 work group has defined a pre-authentication scheme; however, the defined scheme works in the MAC layer and does not work in the network layer in IP routing-based multi-domain networks. In this study, the authors proposed a practical secure and fast handoff framework, called V2V, which not only extends the 802.11i pre-authentication scheme to overcome the above limitations, but also supports pre-configuration with dynamic host configuration protocol to reduce the handoff delay further. A prototype of the V2V system is implemented and the testing results show that one can reduce the overall handoff delay, including association, authentication, IP configuration and mobile IP location update, to no more than 50 ms, which can support most time-sensitive applications such as VoIP.

Performance Evaluation of QoS Parameters during WiMAX to WiMAX Handoff using NS2 and QualNet

Terminal mobility with Quality of Service (QoS) can be provided through efficient and seamless handoffs and handoff management procedures in 4G wireless access networks. The primary objective of this work is to analyze the handoff management procedures within a WiMAX access networks and to evaluate its impact on different QoS metrics such as Packet Loss, Throughput and End-to-End Delay. The performance analysis is done using two simulators namely Network Simulator and QualNet. Simultaneously the work also evaluates the reliability of ns2 by comparing the results with QualNet so as to ascertain its usability for vertical handoff management procedures. This type of experimentation is very useful to help students understand the handoff concept in a very simple and lucid manner

RSVP Extensions for Mobility Management in Heterogeneous WLAN/WiMAX Networks

Quality of service (QoS) is so significant that it cannot be neglected in the recent evolution of wireless mobile networks, which are characterized by great heterogeneity. Handoff delay is one of the problematic issues that users are facing in the heterogeneous networks. In the wireless networks, many mobile users still cannot obtain the network resources they need when applying real-time services while handoff occurs. Consequently, providing a seamless handoff for QoS connections in heterogeneous wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) is crucial. In this paper, a resource ReSerVation Protocol (RSVP) extension scheme for seamless handoff in heterogeneous WLAN/WiMAX networks is proposed. The proposed scheme is based on QoS aware mobility architecture to guarantee a certain degree of QoS. The network selection is initiated by the mobility of the mobile station (MS) and pre-handoff is performed, basing on received signal strength (RSS). Simulation results show that the proposed scheme outperforms the previous schemes.

Measured Downlink Throughput Performance of MBWA System in Urban Area

This paper describes downlink throughput performances measured in a mobile broadband wireless access (MBWA) system field trial with Fast Low-latency Access with Seamless Handoff Orthogonal Frequency Division Multiplexing (FLASH-OFDM). The field trial results show that the downlink cell sizes are 0.4km2, 0.6km2, and 1.7km2 when the sector antenna heights are 19m, 58m, and 84m, respectively, assuming the following items. (1) The cell shape is circular. (2) The cell edge is defined as the location where the average downlink throughput is 1.5Mbit/s.

Optimized Seamless Handoff Latency in Wireless Networks

Optimized Seamless Handoff Latency in Wireless Networks

Fuzzy Logic Based Handover Decision System

With the development of wireless communication technology, various wireless networks have been deployed. Heterogeneous networks will be dominant in the next generation wireless networks. In such networks, providing a seamless handoff by selecting the appropriate network is one of the key issues. In order to be always best connected for various applications, the network selection procedure, in heterogeneous multi-access environment during vertical handover decision is intended to choose the most suitable network for mobile user. In this paper, a handoff decision scheme is proposed that will help to choose the correct network and fuzzy logic is applied to deal with the imprecise information of some criteria and user preference. An algorithm is proposed in which the received signal strength is pre determined. The predetermination of received signal strength will help in reducing the call drop probability. The Sugeno Fuzzy Inference System is used for handover decision. The advantage of Sugeno Fuzzy Inference System is that it works well with linear techniques and mathematical analysis. Here Predetermined received signal strength, bandwidth and user’s preference are used as the parameters on which the handover decision depends. The simulation result shows that if the value of handoff decision is above the threshold value then process of handoff will occur.

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.

A Channel Splitting Strategy for Reducing Handoff Delay in Internet-Based Wireless Mesh Networks

Seamless intergateway handoff support is an essential issue to ensure continuous communications in Internet-based wireless mesh networks (WMNs). Due to the existence of multihop wireless links, traditional handoff schemes designed for single-hop wireless access networks can hardly guarantee the low handoff latency requirement in multihop WMNs. Existing solutions on reducing the handoff delay in WMNs ignore one important factor for the long handoff delay: the channel access delay of handoff signaling packets over the multihop wireless mesh backbone network. In this paper, we address the seamless intergateway handoff issue in Internet-based WMNs from a different perspective and propose a channel splitting strategy to reduce the channel access delay of handoff signaling packets over multihop wireless links. The handoff procedures of two scenarios when a mobile node has one or two transceivers are designed, and two transmission strategies for scheduling the delivery of handoff signaling packets are proposed. Simulation results show that by using the proposed channel splitting strategy, the handoff delay requirement in WMNs can be guaranteed, regardless of the background data traffic, and the average channel utilization can also be improved.

끊김 없는 핸드오프를 위한 다중 인터페이스 이동형 게이트웨이 설계 및 구현

이동형 게이트웨이(MG: Mobile Gateway)는 버스와 같은 차량에 탑승한 사용자들에게 인터넷 서비스를 제공하기 위한 무선랜 장치이다. 논문에서 다루는 MG는 인터넷 연결을 위해 도로변에 설치된 무선랜 기반 소형기지국(RSU AP : Road Side Unit AP)에 접속한다. 차량 이동 중에도 안정적인 통신 서비스를 제공하려면 MG의 접속 RSU가 바뀌는 핸드오프 과정이 빠르고 안정적으로 처리되어야 한다. 그런데 무선랜 기술 특성 상 핸드오프 과정의 통신 단절을 줄이는 데는 물리적 한계가 있다. 본 논문에서는 RSU 접속을 위한 무선랜 인터페이스를 복수 개로 사용하여 끊김 없는 핸드오프를 실현하는 다중 인터페이스 MG (MIMG : Multi-Interface MG)를 제안한다. 안정적인 핸드오프를 위한 구체적 방법으로 MIMG로부터 RSU로의 패킷 전송 단절을 제거하기 위한 Link Sharing 기법, RSU로부터 MIMG로의 패킷 전송 단절을 제거하기 위한 Path Sharing 기법을 제안한다. 우리는 임베디드 보드를 이용하여 제안한 핸드오프 기법을 실현한 MIMG를 구현하였고 이를 이용하여 성능 평가실험을 수행하였다. 실험 결과 단일 인터페이스를 가진 MG와 달리 MIMG는 핸드오프 시의 통신 단절을 제거할 수 있었고 대역폭도 50% 이상 향상됨을 확인하였다. Mobile Gateway(MG) is a wireless LAN device to provide internet services to a passenger on vehicles like a bus. For using internet services, MG connects the Road Side Unit AP(RSU AP) based on WLAN .To provide a stable communication service on the moving vehicle, handoff changing MG's RSU must be handled fast and stably. However, it has a physical limits to remove a disconnection time of handoff process by reason of its technological features. In this paper, we suggest a MIMG(Multi-Interface Mobile Gateway) executing seamless handoff by using multiple wireless LAN interfaces for connecting RSU. In the detailed way to do stable handoff, we suggest the "Link Sharing Technique" to disconnection time of packet transmission for RSU to MIMG and the "Path Sharing Technique" to remove disconnection time of packet transmission for MIMG to RSU. we implemented the MIMG which performs the suggested handoff technique. We confirmed the superiority of our system by remove of the disconnection time(0 ms), and improved over 50 % of the communication bandwidth.

Dynamic Inter Arrival Time Based Seamless Handoff for Mobile WIMAX Ping-Pong Calls Bypassing PKMv2 EAP Authentication

The rapid growth of wireless communication and its persistent use influences all walks of life. Mobile WiMAX IEEE 802.16e standard enabled convergence of mobile and fixed broadband networks through a common wide-area radio-access technology and flexible network architecture. It aims to provide seamless support to its users but an inevitable is that the long delay which occurs during the handoff management in every network process. This paper proposes a Dynamic Interval based Processing Algorithm to separate ping-pong users from the pool of users and to process them separately thus reducing the overhead of network re-entry process. Incoming users are divided into three categories like new user, old user and ping pong user. New user should undergo all the phases of network entry process, old user is provided with authentication key which leads to skipping of steps in generation of keys. Proposed algorithm deals with identifying the ping pong users by calculating the inter arrival duration and rate with same base station. When assured authenticated ping-pong users enter the network next time within the allotted time they will be provided with last used Traffic Encryption Key (TEK) thus bypassing key generation phase . It is observed that the proposed work performs the authentication phase and cancels the key generation phase which leads to minimum network entry delay and it saves to the maximum of 80% processing time. The network model was developed using Network Simulator and the algorithm was implemented in MATLAB GUIDE which gets connected to the database developed in MYSQL.This approach is justified through its timing analysis result which proves the efficient swift in the handoff processes.

An architectural framework for seamless handoff between IEEE 802.11 and UMTS networks

In recent years, Cellular wireless technologies like GPRS, UMTS, CDMA and Wireless Local Area Network (WLAN) technologies like IEEE 802.11 have seen a quantum leap in their growth. Cellular technologies can provide data services over a wide area, but with lower data rates. WLAN technologies offer higher data rates, but over smaller areas, popularly known as `Hot Spots'. The demand for an ubiquitous data service can be fulfilled, if it is possible for the end-user to seamlessly roam between these heterogeneous technologies. In this paper, a novel framework is proposed consisting of intra-ISP network called `Intermediate Switching Network'(ISN) fused between UMTS and WLAN networks as well as data (Internet) services for providing seamless mobility without affecting user's activities. The ISN uses MPLS and Multiprotocol-BGP to switch the data traffic between UMTS to IEEE 802.11 networks, as per the movements of the user. The ISN is integrated with the UMTS network at the GGSN-3G and at the Access Point for IEEE 802.11 network respectively. The simulation result shows the improved performance of the ISN based framework over existing schemes.

Identity‐based construction for secure and efficient handoff authentication schemes in wireless networks

ABSTRACTWith the rapid development of computer networks, wireless technologies find important applications in roaming communication. In this scenario, practical needs initiate the demand for a secure and efficient handoff authentication scheme. To the best of our knowledge, however, there exists no scheme that can simultaneously provide robust security properties and enjoy desirable efficiency. In this paper, we first examines the security of the scheme proposed in International Conference on Communications 2007 by Kim et al. and demonstrates that the scheme of Kim et al. fails to achieve perfect forward/backward secrecy. Furthermore, we propose a new identity‐based construction for secure and efficient handoff authentication schemes, in which an identity‐based online/offline encryption scheme is the primary ingredient. Compared with the scheme of Kim et al., our construction enjoys desirable efficiency in terms of the computation cost and the communication cost. To be specific, the developed scheme not only realizes a seamless handoff with key agreement, but also provides perfect forward/backward secrecy, which has never been achieved in any existing handoff‐related schemes. Therefore, our construction is more suitable for handoff authentication in the wireless applications environment. Copyright © 2012 John Wiley & Sons, Ltd.

H.264/SVC vs. H.264/AVC video quality comparison under QoE-driven seamless handoff

This paper studies the impact of mobility management and seamless handover mechanisms on the perceived quality of video streaming applications. A seamless handoff scheme is proposed that incorporates IEEE 802.21 Media Independent Handover framework and a QoE-driven rate adaptation scheme, for both scalable and single layer coding. Quality of Experience (QoE) has been considered as an important parameter for network selection. The proposed scheme has been implemented and evaluated in a real test-bed network. Objective and subjective quality evaluation measurements for both H.264/AVC and H.264/SVC have been carried out. Through experimentation, QoE driven mobility of video streaming can be better maintained with H.264/SVC under the combined seamless handoff and rate adaptation functionality.

An improved consumer goods market model-based vertical handoff decision algorithm

Seamless mobility support in a heterogeneous roaming environment is one of several challenging issues for next-generation wireless network, and handoff decision is an important and intelligent part of seamless handoff process. In this paper, an improved game theory-based vertical handoff decision algorithm is presented. The proposed algorithm formulates the relationship between mobile nodes and heterogeneous access networks as a special consumer goods market model, and formulates the relationship among candidate access networks as cooperative game process. The simulation experimental results show that the proposed network selection algorithm is able to achieve the load balancing well, and make the networks obtain larger payoff.

A hybrid system integrating signal analysis and probabilistic neural network for user motion detection in wireless networks

This paper proposes a novel user motion detection (UMD) model called PNN-MSMD and its application on seamless handoff. The PNN-MSMD uses a novel signal analysis model to identify the movement of a mobile device without using a location system. The PNN-MSMD integrates multiple signal processing sensors with probabilistic neural network (PNN) to analyze the received signal strength (RSS) of a mobile device. The PNN uses the variation of RSS derived from the sensors as input training data to learn the moving patterns and generate the classification rules for detecting the motion state of a mobile device. The detection results can help mobile devices to enhance handoff processes. Computer simulations show that the proposed PNN-MSMD based handoff algorithm performs better than four traditional handoff algorithms and two motion detection based handoff algorithms. The PNN-MSMD method can save up to 82.56% power consumption and reduce up to 42.51% number of handoffs.

A Fast Seamless Handoff Scheme between IEEE 802.11 and EPS Networks Using Optimized Proxy Mobile IPv6

A Fast Seamless Handoff Scheme between IEEE 802.11 and EPS Networks Using Optimized Proxy Mobile IPv6

Fast Handoff Mechanism in Wireless Local Area Networks 'WLAN' using Neighbor Graph Algorithm

progress in the research and development in wireless technology has created different types of high performance and highly optimized wireless networks. They provide various types services like VoIP, multimedia, video conference, chatting etc. Unreliable and inefficient handoff procedures reduce the quality and reliability of the networks. So to maintain a certain level of Quality of Service (QoS) a seamless handoff should be ensured. Throughout the last few years there has been plenty of research aimed towards reducing handoff delay incurred in the different level of wireless communications. Here we propose a fast handoff method in which we use pre-authentication based on Neighbor Graph Algorithm.

Achieving seamless handoffs via backhaul support in Wireless Mesh Networks

In Wireless Mesh Networks (WMNs), mobile clients may experience frequent handoffs due to the relatively small transmission range of the mesh routers. Each handoff may lead to packet delays and/or packet losses, which limits the performance of real-time applications over WMNs. In this work, we propose BASH--a Backhaul-Aided Seamless Handoff scheme. BASH takes advantage of the wireless backhaul feature of WMNs, and allows a mobile station to directly access the backhaul channel to probe the neighboring mesh routers. Our work shows that by utilizing the wireless backhaul, BASH (1) reduces the probing latency and, thus, the Layer-2 handoff latency; (2) allows partial overlap of the Layer-2 and Layer-3 handoffs, reducing the overall handoff latency; and (3) shortens the authentication latency by utilizing the transitivity of trust relationship. The experimental results show that BASH achieves an average Layer-2 handoff of 8.9 ms, which supports real-time applications during the handoff.

A cross‐layer partner‐assisted handoff scheme for hierarchical mobile IPv6 in IEEE 802.16e systems

AbstractThe design of the seamless handoff is the key issue in the next‐generation mobile networks. A new broadband wireless access, called WiMAX, has been specified in the IEEE 802.16e standard document, to provide the high bandwidth and the large coverage area than the IEEE 802.11‐based wireless networks. In the IP‐based mobile network, mobile IPv6 (MIPv6) protocol provides the binding update message to update the mobile station's IP information for supporting the layer 3 mobility. Hierarchical mobile IPv6 (HMIPv6) protocol is proposed by employing a hierarchical network structure to reduce handoff latency. HMIPv6 protocol suffers the long handoff delay and the high packet lost in the macro mobility. This paper presents a new cross‐layer partner‐assisted handoff mechanism based on HMIPv6, termed as P_HMIPv6 protocol. The P_HMIPv6 protocol is a cross‐layer approach by the combination of layer 2 and layer 3. The partner station (PS) is a new component with relay ability and adopted by our protocol. With the assistance of the PS, care‐of address (CoA) is pre‐acquired and DAD operation is pre‐executed by the PS before the MS initiates the layer 2 handoff. The simulation results show that P_HMIPv6 protocol actually achieves the performance improvements in handoff delay time, packet loss rate, and handoff delay jitter. Copyright © 2009 John Wiley & Sons, Ltd.