Showing papers on "Handover published in 2008"

Mobile IPv6 Fast Handovers

Abstract: Mobile IPv6 enables a mobile node (MN) to maintain its connectivity to the Internet when moving from one Access Router to another, a process referred to as handover. During handover, there is a period during which the mobile node is unable to send or receive packets because of link-switching delay and IP protocol operations. This "handover latency" resulting from standard Mobile IPv6 procedures (namely, movement detection, new Care-of Address configuration, and Binding Update) is often unacceptable to real-time traffic such as Voice over IP (VoIP). Reducing the handover latency could be beneficial to non- real-time, throughput-sensitive applications as well. This document specifies a protocol to improve handover latency due to Mobile IPv6 procedures. This document does not address improving the link- switching latency. This document updates the packet formats for the Handover Initiate (HI) and Handover Acknowledge (HAck) messages to the Mobility Header Type. [STANDARDS-TRACK]

An MDP-Based Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks

Abstract: The architecture for the Beyond 3rd Generation (B3G) or 4th Generation (4G) wireless networks aims at integrating various heterogeneous wireless access networks. One of the major design issues is the support of vertical handoff. Vertical handoff occurs when a mobile terminal switches from one network to another (e.g., from wireless local area network to code-division multiple-access 1x radio transmission technology). The objective of this paper is to determine the conditions under which vertical handoff should be performed. The problem is formulated as a Markov decision process with the objective of maximizing the total expected reward per connection. The network resources that are utilized by the connection are captured by a link reward function. A signaling cost is used to model the signaling and processing load incurred on the network when vertical handoff is performed. The value iteration algorithm is used to compute a stationary deterministic policy. For performance evaluation, voice and data applications are considered. The numerical results show that our proposed scheme performs better than other vertical handoff decision algorithms, namely, simple additive weighting, the technique for order preference by similarity to ideal solution, and Grey relational analysis.

Hierarchical Mobile IPv6 (HMIPv6) Mobility Management

Abstract: This document introduces extensions to Mobile IPv6 and IPv6 Neighbour Discovery to allow for local mobility handling. Hierarchical mobility management for Mobile IPv6 is designed to reduce the amount of signalling between the Mobile Node, its Correspondent Nodes, and its Home Agent. The Mobility Anchor Point (MAP) described in this document can also be used to improve the performance of Mobile IPv6 in terms of handover speed.

An Analytical Framework for Performance Evaluation of IPv6-Based mobility Management Protocols

Abstract: Mobility management with provision of seamless handover is crucial for an efficient support of global roaming of mobile nodes (MNs) in next-generation wireless networks (NGWN). Mobile IPv6 (MIPv6) and its extensions were proposed by IETF for IP layer mobility management. However, performance of IPv6-based mobility management schemes is highly dependent on traffic characteristics and user mobility models. Consequently, it is important to assess this performance in-depth through those two factors. The performance of IPv6-based mobility management schemes is usually evaluated through simulations. This paper proposes an analytical framework to evaluate the performance of IPv6-based mobility management protocols. This proposal does not aim to advocate which is better but rather to study the effects of various network parameters on the performance of these protocols to enlighten decision-making. The effect of system parameters, such as subnet residence time, packet arrival rate and wireless link delay, is investigated for performance evaluation with respect to various metrics like signaling overhead cost, handoff latency and packet loss. Numerical results show that there is a trade-off between performance metrics and network parameters.

Media-independent handover for seamless service provision in heterogeneous networks

Abstract: The performance of current Internet applications is based mainly on the capabilities of the underlying network technologies. Modern access systems usually can satisfy delay, loss, or bandwidth requirements; however, design inconsistencies can lead to service degradation as the terminals move across different systems. In this article, the focal point is the satisfaction of service requirements during mobility and more specifically, how the emerging IEEE 802.21 standard enables seamless, inter-technology handover. Based on prior work and a well-known example of seamless mobility, the main seamless mobility principles are identified and used as the basis for further evaluating the potential of the IEEE 802.21 standard to meet the requirements of applications for minimum disruption during an inter-technology handover.

An overview of IEEE 802.21: media-independent handover services

Abstract: In recent years multitechnology-enabled terminals have become available. Such multimode terminals pose new challenges to mobility management. In order to address some of these challenges, the IEEE is currently working on a new specification on media-independent handover services (IEEE 802.21 MIH). The main aim of this specification is to improve user experience of mobile terminals by enabling handovers between heterogeneous technologies while optimizing session continuity. In this article we provide an overview of the current status of the IEEE 802.21 specification.

Method and apparatus for resource management in handover operation

Abstract: A method and apparatus for resource management during handover operation includes initiating a handover from a first access network to a second access network. A policy update message is sent and a policy update confirmation message is received. A general packet radio service (GPRS) tunneling protocol (GTP) message and a radio access bearer (RAB) release message is sent and a GTP and RAB release acknowledgment is received. Connectivity is established for uplink and downlink transmission in the second access network.

Coordinated load balancing, handoff/cell-site selection, and scheduling in multi-cell packet data systems

Abstract: We investigate a wireless system of multiple cells, each having a downlink shared channel in support of high-speed packet data services. In practice, such a system consists of hierarchically organized entities including a central server, Base Stations (BSs), and Mobile Stations (MSs). Our goal is to improve global resource utilization and reduce regional congestion given asymmetric arrivals and departures of mobile users, a goal requiring load balancing among multiple cells. For this purpose, we propose a scalable cross-layer framework to coordinate packet-level scheduling, call-level cell-site selection and handoff, and system-level cell coverage based on load, throughput, and channel measurements. In this framework, an opportunistic scheduling algorithm--the weighted Alpha-Rule--exploits the gain of multiuser diversity in each cell independently, trading aggregate (mean) down-link throughput for fairness and minimum rate guarantees among MSs. Each MS adapts to its channel dynamics and the load fluctuations in neighboring cells, in accordance with MSs' mobility or their arrival and departure, by initiating load-aware handoff and cell-site selection. The central server adjusts schedulers of all cells to coordinate their coverage by prompting cell breathing or distributed MS handoffs. Across the whole system, BSs and MSs constantly monitor their load, throughput, or channel quality in order to facilitate the overall system coordination. Our specific contributions in such a framework are highlighted by the minimum-rate guaranteed weighted Alpha-Rule scheduling, the load-aware MS handoff/cell-site selection, and the Media Access Control (MAC)-layer cell breathing. Our evaluations show that the proposed framework can improve global resource utilization and load balancing, resulting in a smaller blocking rate of MS arrivals without extra resources while the aggregate throughput remains roughly the same or improved at the hot-spots. Our simulation tests also show that the coordinated system is robust to dynamic load fluctuations and is scalable to both the system dimension and the size of MS population.

A Traveling Distance Prediction Based Method to Minimize Unnecessary Handovers from Cellular Networks to WLANs

Abstract: We propose a handover decision method based on the prediction of traveling distance within an IEEE 802.11 wireless local area network (WLAN) cell. The method uses two thresholds which are calculated by the mobile terminal (MT) as it enters the WLAN cell. The predicted traveling distance is compared against these thresholds to make a handover decision in order to minimize the probability of handover failures or unnecessary handovers from a cellular network to a WLAN. Our analysis shows that the proposed method successfully keeps the number of failed or unnecessary handovers low.

A Noncooperative Game-Theoretic Framework for Radio Resource Management in 4G Heterogeneous Wireless Access Networks

Abstract: Fourth generation (4G) wireless networks will provide high-bandwidth connectivity with quality-of-service (QoS) support to mobile users in a seamless manner. In such a scenario, a mobile user will be able to connect to different wireless access networks such as a wireless metropolitan area network (WMAN), a cellular network, and a wireless local area network (WLAN) simultaneously. We present a game-theoretic framework for radio resource management (that is, bandwidth allocation and admission control) in such a heterogeneous wireless access environment. First, a noncooperative game is used to obtain the bandwidth allocations to a service area from the different access networks available in that service area (on a long-term basis). The Nash equilibrium for this game gives the optimal allocation which maximizes the utilities of all the connections in the network (that is, in all of the service areas). Second, based on the obtained bandwidth allocation, to prioritize vertical and horizontal handoff connections over new connections, a bargaining game is formulated to obtain the capacity reservation thresholds so that the connection-level QoS requirements can be satisfied for the different types of connections (on a long-term basis). Third, we formulate a noncooperative game to obtain the amount of bandwidth allocated to an arriving connection (in a service area) by the different access networks (on a short-term basis). Based on the allocated bandwidth and the capacity reservation thresholds, an admission control is used to limit the number of ongoing connections so that the QoS performances are maintained at the target level for the different types of connections.

Cross-Layer-Based Adaptive Vertical Handoff With Predictive RSS in Heterogeneous Wireless Networks

Abstract: A heterogeneous wireless network consists of various wireless networks [e.g., Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Fidelity (WiFi)] and cellular communications [e.g., beyond the third generation (B3G) and the fourth generation (4G)]. Vertical handoff is an important mechanism for achieving continuous seamless transmissions in these networks. In contrast to horizontal handoff, vertical handoff considers not only the received signal strength (RSS) but also the service-class mapping between handoff-in and handoff-out networks. Most previous works have adopted the RSS-based mechanism to determine handoff thresholds, which causes a serious ping-pong effect that increases unnecessary handoff. Although integrating the RSS-based mechanism with a hysteresis method reduces the unnecessary handoff, it suffers from high dropping [i.e., high Sum of Weighted Grade of Service (SWGoS)] and low utilization. Therefore, this paper proposes a cross-layer-based adaptive vertical handoff algorithm with predictive RSS to reduce the unnecessary handoff while significantly increasing utilization and decreasing connection dropping. The proposed approach determines the optimal target network in two phases, i.e., polynomial regression RSS prediction and Markov decision process analysis. Furthermore, fast changes in bandwidth caused by vertical handoff result in inaccurate Transmission Control Protocol (TCP) congestion control and, thus, reduce the TCP goodput. The cross-layer scheme provides a TCP receiver to reply to the TCP sender with the wireless network's protocol type. By using the cross-layer information, the TCP sender can accurately predict the available bandwidth and increase the network goodput. Numerical results indicate that the proposed cross-layer-based approach outperforms the other approaches in the number of vertical handoffs and SWGoS while yielding competitive utilization. In addition, the cross-layer scheme cooperates with existing TCP algorithms to increase goodput by up to 18%.

CLINICAL PRACTICE Interprofessional handover and patient safety in anaesthesia: observational study of handovers in the recovery room †

Abstract: Background. We aimed to describe how anaesthetists hand over information and professional responsibility to nurses in the operating theatre recovery room. Methods. We carried out non-participant practice observation and in-depth interviews with practitioners working in the recovery room of an English hospital and used qualitative methods to analyse the resulting transcripts. Results. We observed 45 handovers taking place between 17 anaesthetists and 15 nurses in the recovery room of the operating theatre suite. These took place in an environment that is event-driven, time-pressured, and prone to concurrent distractions. Anaesthetists and nurses often had differing expectations of the content and timing of information transfer. The point at which transfer of responsibility for the patient occurred during the handover process was variable and depended not only on the condition of the patient but also on the professional relationship between the nurse and doctor concerned. Handover also provided an ‘audit point’ in care where the patient’s intraoperative progress was reviewed and plans were made for further management. Here, as in the transfer of responsibility, we found evidence that nurses play a greater role in defining the limits of anaesthetists’ practice than might be expected. Conclusions. Patient handovers in the recovery room are largely informal, but nevertheless show many inherent tensions, both professional and organizational. Although formalized handover procedures are often advocated for the promotion of safety, we suggest that they are likely to work best when the informal elements, and the cultural factors underlying them, are acknowledged. Br J Anaesth 2008; 101: 332–7

Spectrum Handoff for Cognitive Radio Networks: Reactive-Sensing or Proactive-Sensins?

Abstract: In this paper, we will investigate the spectrum handoff schemes for the cognitive radio networks. Spectrum handoff occurs when the primary users appear and the secondary users are using this particular primary user's licensed channel. We compare two major types of spectrum handoff schemes. One is the reactive-sensing spectrum handoff, where the target channel for spectrum handoff is selected or sensed only after the spectrum handoff request is made. The other one is the proactive-sensing spectrum handoff, for which the target channel is predetermined. The advantage of the reactive spectrum handoff is the accuracy of the selected target channel, but pay the cost of sensing time. By contrast, the proactive spectrum handoff avoid the sensing time, but the pre-determined target channel may not be available. We will provide a preemptive resume priority M/G/1 queueing network model to analyze in which condition that the reactive- or proactive-sensing spectrum handoff should be used dependent of sensing time.

Mapping quality of service for intersystem handover

Abstract: In accordance with the exemplary embodiments of the invention there is a method, executable computer program, and apparatus for receiving information including at least one packet data protocol context of a target network, and based on the information, for mapping in a source network at least one bearer to the at least one packet data protocol context. In addition, in accordance with another exemplary embodiment of the invention there is a method, executable computer program, and apparatus for receiving from a source network device information comprising an indication of at least one bearer mapped to the at least one packet data protocol context of a target network, and storing the received information for use in a handover.

Cost-Function-Based Network Selection Strategy in Integrated Wireless and Mobile Networks

Abstract: Wireless and mobile networks have experienced great success over the past few years. However, any single type of wireless and mobile network cannot provide all types of services, e.g., wide coverage and high bandwidth. An integrated wireless and mobile network is introduced by combining these different types of wireless and mobile networks, which can provide more comprehensive services. In an integrated wireless and mobile network, a mobile terminal that is equipped with heterogeneous network interfaces is capable of accessing all the available networks. Therefore, how to select a desired network is an important issue for the integrated wireless and mobile network. Although some network-selection strategies have been proposed, most of them are designed to meet a user's individual needs, such as the bandwidth, the access fee, or the power consumption. The system performance also has not been touched. In this paper, we propose a cost-function-based network selection (CFNS) strategy in an integrated wireless and mobile network from a system's perspective, which also considers a user's needs. We also analyze the system performance of the proposed network-selection strategy by using a theoretical model and extensive simulations. The results obtained show that the proposed network-selection strategy affects multiple system parameters, which needs to be handled carefully.

Fast radio link recovery after handover failure

Abstract: A radio connection is supported between the mobile station and a source base station associated with a source cell. The mobile station transmits information to the source base station over a shared uplink data communications channel used by multiple mobiles. A handover message is received from the source base station indicating that the source base station has initiated a handover of the radio connection over to a target base station for the target base station to support the radio connection. The handover fails. In response, a message is sent from the mobile station to the source base station requesting that the source base station continue to support the radio connection without requiring the mobile station to perform a radio channel procedure competing with other mobile stations requesting a new radio connection be supported by the source base station.

Fuzzy-based Spectrum Handoff in Cognitive Radio Networks

Abstract: This paper focuses on spectrum handoffs in a cognitive radio network where secondary (unlisenced) users (i.e. cognitive radios) opportunistically use frequency channels as long as the aggregate interference caused at the primary (licensed) users does not exceed a certain threshold. When harmful interference is caused to a primary user, or when the quality of service perceived by a secondary user is not satisfactory, the secondary user has to initiate a spectrum handoff to quickly vacate the channel it is occupying. The proposal in this paper is a fuzzy-based approach able to make effective spectrum handoff decisions in a context characterized by uncertain, incomplete and heterogeneous information.

Performance Analysis and Optimization of Handoff Algorithms in Heterogeneous Wireless Networks

Abstract: In heterogeneous wireless networks, handoff can be separated into two parts: horizontal handoff (HHO) and vertical handoff (VHO). VHO plays an important role to fulfill seamless data transfer when mobile nodes cross wireless access networks with different link layer technologies. Current VHO algorithms mainly focus on when to trigger VHO, but neglect the problem of how to synthetically consider all currently available networks (homogeneous or heterogeneous) and choose the optimal network for HHO or VHO from all the available candidates. In this paper, we present an analytical framework to evaluate VHO algorithms. Subsequently, we extend the traditional hysteresis based and dwelling-timer based algorithms to support both VHO and HHO decisions and apply them to complex heterogeneous wireless environments. We refer to these enhanced algorithms as E-HY and E-DW, respectively. Based on the proposed analytical model, we provide a formalization definition of the handoff conditions in E-HY and E-DW and analyze their performance. Subsequently, we propose a novel general handoff decision algorithm, GHO, to trigger HHO and VHO in heterogeneous wireless networks. Analysis shows that GHO can achieve better performance than E-HY and E-DW. Simulations validate the analytical results and verify that GHO outperforms traditional algorithms in terms of the matching ratio, TCP throughput and UDP throughput.

Forward handover under radio link failure

Abstract: System(s) and method(s) are provided for forward handover under radio link failure. A configurable criterion for radio link failure (RLF) is established through a reference threshold for a channel quality metric; the threshold (CQITH) can be determined at least on a quality-of-service basis or a per-terminal basis. A low-overhead indication of RLF is conveyed as a NULL CQI when the channel quality metric is below threshold. Onset of RLF triggers preparation of forward handover (FHO) at a terminal within a predetermined timer, during which normal service can resume if link quality recovers above CQITH. Forward handover is pursued once timer elapses. Preparation at the terminal can be complemented by preparation implemented in advanced to RLF condition, in accordance to a disparate threshold applied to terminal's measurements. Preparation of FHO includes backhaul exchange of operational information like buffered data, and context.

Handover from e-utran to utran/geran cs

Abstract: The present invention relates to a method for a handover of a UE (User Equipment) currently engaged in a voice call. More particularly, the invention relates to a handover from 1) a packet based radio where Voice Service is provided via VoIP over the radio and is controlled via Session Initiation Protocol (SIP) based signalling (e.g. LTE, E-UTRAN or WIMAX radio) to 2) a radio access network where Voice Service can be only provided via circuit switched (CS) domain (a visited mobile switching centre (VMSC) is needed) such as legacy 3GPP UMTS Terrestrial Radio Access Network (UTRAN)/ GSM/Edge Radio Access Network (GERAN) coverage. A MSC-S entity acting as a Packet Core Control Node on a Packet Switched (PS) network and as an Anchor Visited Mobile Switching Centre (VMSC) for a handover to a Circuit Switched (CS) network on the CS domain side is proposed, the MSC-S preparing a new path with a remote UE-B and a CS domain handover towards a target legacy radio coverage before requesting a UE- A to execute the handover.

Handover mechanism that exploits uplink channel quality of a target cell

Abstract: System(s) and method(s) are provided for handover of a mobile terminal in a wireless communication system. Handoff resolution relies on both a downlink channel quality indication between a serving base station and the mobile terminal, and uplink channel quality indications amongst the terminal and a measurement set of target base stations. To generate UL channel quality indicators, the mobile station conveys a narrowband or broadband sounding reference signal, and serving and target base stations measure UL and DL performance metrics (e.g., RSRP, RSSI, or RSOT). In backward handover, UL channel state information from target cells is received at the serving base station through backhaul communication, and handoff is resolved based on both UL and DL quality reports. In forward handover, the set of UL quality reports are conveyed to the mobile station to determine a target cell for handoff.

Online charging for sessions that are transferred between network domains

Abstract: Communication networks and methods are disclosed for providing online charging for a session of a dual mode device that is transferred (seamless handover) from a first network domain to a second network domain. For the session involving the dual mode device, a handover application server or another network element generates a handover charging identifier that may be used in the first network domain and the second network domain. The handover application server then distributes the handover charging identifier to network elements in the second network domain and the first network domain. The network elements in the first network domain and the second network domain insert the handover charging identifier and other context information in online charging requests that are transmitted to an online charging system. The online charging system is then able to correlate online charging requests from both the first network domain and the second network domain.

Source initiated communication handover

Abstract: In a handover operation an access terminal is handed over from a source access point to a target access point. To facilitate efficient identification of a target access point, a handover operation may be initiated by the target access point. A candidate frequency search also may be invoked to confirm that an access terminal identified by a target access point for a handover is in the vicinity of the target access point. A source access point may verify whether an access terminal is in a vicinity of a target access point to determine whether to perform a handover operation. A source access point may handle potential ambiguity between several target access points by sending handover commands to each of these target access points. An access terminal also may assist in the determination of whether to perform a handover operation.

A Vertical Handoff Decision Scheme in Heterogeneous Wireless Systems

Abstract: One of the goals of next generation wireless networks (NGWNs) refers to the ability of supporting heterogeneous wireless access technologies. The objective is to provide a diverse range of seamlessly provide high-data rate multimedia services across different wireless networks. To achieve this, we must rely on seamless vertical handoff techniques. In this paper, we propose a distributed Simple Additive Weighting (SAW)-based vertical handoff mechanism. Our main goal is to reduce the processing overhead in the mobile terminal by delegating the calculation of handoff metrics for network selection to the Visiting Networks i.e. WiFi.

Method and apparatus for supporting sip/ims-based femtocells

Abstract: A femtocell is integrated into a core network so as to securely and efficiently deliver one or more mobile services to an end user on an existing mobile device over a broadband connection. This integration can be into a basic Internet Protocol (IP)-based network, or an IMS -based network. In an illustrated embodiment, a femtocell is integrated to a SIP- or IMS-based network using a 'convergence' server. The convergence server preferably is a S IP-based fixed mobile convergence (FMC) application server that provides an all-IP approach to core network integration for femtocells. The convergence server provides a number of high level functions including secure access of an end user mobile device into the core network through the femtocell (which involves authenticating the femtocell as well as a specific end user mobile device), single number voice and messaging services (by updating an end user's location to be the femtocell), mobility (to support handover between the femtocell and macro cell networks), delivery of supplementary services (such as call waiting, call hold, caller ID, three-way calling, and the like) on the femtocell network, and the delivery of new and advanced services (such as home landline routing, mobile TV, multimedia downloads and the like).

Nursing handover: it's time for a change.

Abstract: Nursing handover is a common part of nursing practice that is fundamental to safe patient care. Despite this, the literature provides little direction on the best way to conduct handover. This project aimed to examine nurses' perceptions of handover and to determine the strengths and limitations of the handover process. A staff survey was distributed to nurses in all inpatient wards at a metropolitan tertiary hospital. A total of 176 nurses responded to the staff survey. The findings revealed conflicting opinions about the effectiveness of the handover process; although a number of nurses were positive about current handover practice, indicating they were provided with sufficient information about patients and given opportunity to clarify patient care information, other nurses identified aspects of handover that could be improved. These included: the subjectivity of handover information, the time taken to conduct handover, repetition of information that could be found in the patients' care plans, and handing over of information by a nurse who has not cared for the patient. Some attention needs to be given to addressing the perceived weaknesses associated with the handover process. (author abstract)

Handover method with link failure recovery, wireless device and base station for implementing such method

Abstract: For each target cell determined by a handover decision process, a first message is transmitted from a source base station (20S) to a target base station (20T) servicing that target cell. The first message includes an identifier of a wireless device (10) having a communication link with the source base station and information for obtaining authentication data for this wireless device. The authentication data depends on a secret key available to the wireless device and the source base station and on an identity of the target cell. Upon failure of the communication link, a cell is selected at the wireless device, which transmits to that cell a reestablishment request message including its identifier and authentication data depending on the secret key and on an identity of the selected cell. If the selected cell is a target cell serviced by a target base station that received a first message, conformity of the authentication data included in the reestablishment request message with the authentication data obtained from this first message is verified to authorize transfer of the communication link to the selected cell.

DeuceScan: Deuce-Based Fast Handoff Scheme in IEEE 802.11 Wireless Networks

Abstract: The IEEE 802.11 standard has enabled low-cost and effective wireless local area network (WLAN) services. It is widely believed that WLANs will become a major portion of the fourth-generation cellular system. The seamless handoff problem in WLANs is a very important design issue to support the new astounding and amazing applications in WLANs, particularly for a user in a mobile vehicle. The entire delay time of a handoff is divided into probe, authentication, and reassociation delay times. Because the probe delay occupies most of the handoff delay time, efforts have mainly focused on reducing the probe delay to develop faster handoff schemes. This paper presents a new fast handoff scheme (i.e., the DeuceScan scheme) to further reduce the probe delay for IEEE-802.11-based WLANs. The proposed scheme can be useful to improve wireless communication qualities on vehicles. A spatiotemporal approach is developed in this paper to utilize a spatiotemporal graph to provide spatiotemporal information for making accurate handoff decisions by correctly searching for the next access point. The DeuceScan scheme is a prescan approach that efficiently reduces the layer-2 handoff latency. Two factors of stable signal strength and variable signal strength are used in our developed DeuceScan scheme. Finally, simulation results illustrate the performance achievements of the DeuceScan scheme in reducing handoff delay time and packet loss rate and improving link quality.

Handover management in integrated WLAN and mobile WiMAX networks

Abstract: Recently there has been much effort, in both academia and industry, to integrate a plethora of wireless technologies in order to provide ubiquitous broadband access to mobile users. Handover management is still one of the most challenging issues to be solved for seamless integration of wireless networks. This article addresses the integration of IEEE 802.11 WLANs and IEEE 802.16 WMANs, focusing mainly on the handover management aspects. First, we describe architectures, futuristic application scenarios such as the envisioned heterogeneous multihop wireless networks (HMWNs) and moving networks, as well as the related research issues. Second, we present IEEE 802.21, a new emerging standard aimed at providing a framework for media-independent handover(MIH) among heterogeneous networks. Finally, we discuss how the MIH framework can help handover management for the integrated network.