Abstract: The 3GPP LTE system has been designed to offer significantly higher data rates, higher system throughput, and lower latency for delay critical services. This improved performance has to be provided and guaranteed under various mobility conditions. Hence, handover (HO) and its performance are of high importance. This paper investigates the performance of the handover procedure within 3GPP LTE in terms of HO failure rate and the delay of the whole procedure. System level simulations within a typical urban propagation environment, with different User Equipment (UE) speeds, cell radii and traffic loads per cell have been performed. The entire layer 3 signalling exchanged via air interface is considered in the simulations. In addition, errors at the Layer 1 (L1) control channels are taken into account. Simulation results show that the handover procedure within 3GPP satisfies the goal of high performance mobility. Namely for cell radii up to 1 km and for UE speeds up to 120 km/h, the HO failure rate lies within the range of 0-2.2% even in high loaded systems. For medium and low loads even at speeds of 250 km/h, HO failure is below 1.3 %. In addition, simulation results show that the handover procedure is robust against L1 control channel errors.

Abstract: With the proliferation of WiFi technology, many WiFi networks are accessible from vehicles on the road making vehicular WiFi access realistic. However, several challenges exist: long latency to establish connection to a WiFi access point (AP), lossy link performance, and frequent disconnections due to mobility. We argue that people drive on familiar routes frequently, and thus the mobility and connectivity related information along their drives can be predicted with good accuracy using historical information - such as GPS tracks with timestamps, RF fingerprints, and link and network-layer addresses of visible APs. We exploit such information to develop new handoff and data transfer strategies. The handoff strategy reduces the connection establishment latency and also uses pre-scripted handoffs triggered by change in vehicle location. The data transfer strategy speeds up download performance by using prefetching on the APs yet to be encountered. Experimental performance evaluation reveals that the predictability of mobility and connectivity is high enough to be useful in such protocols. In our experiments with a vehicular client accessing road-side APs, the handoff strategy improves download performance by roughly a factor of 2 relative to the state-of-the-art. The data transfer strategy further improves this performance by another factor of 2.5.

Abstract: Background: Poor clinical handover creates discontinuities in care leading to patient harm. However, the field of handover research continues to lack standardised definitions and reliable measurement tools to identify factors that would lead to harm reduction and improved safety strategies. Objective: This paper introduces a conceptual framework to underpin a research agenda around the important patient safety topic of clinical handover. Methods: Five frameworks with potential application to clinical handover were identified in a consultation process with clinicians, researchers and policy makers. Results: The framework consists of three key handover elements—information, responsibility and/or accountability and system—in relation to three key measurement elements—policy, practice and evaluation. Using this framework an analysis of current “gaps” in the measurement of handover was completed. Conclusion: The paper argues that measurement will identify gaps in knowledge about handover practice and promote rigor in the design and evaluation of interventions to reduce patient harm.

Abstract: The present invention provides a method and system for handoff in a wireless communication network. In one embodiment, a common handoff encryption key is generated by an authentication server and transmitted to a first access point and a second access point. The first access point transmits the handoff encryption key to a wireless terminal. The wireless terminal encrypts output data with the handoff encryption key. When the wireless terminal is associated with the second access point, the second access point decrypts data from the wireless terminal with the handoff encryption key. In a second embodiment, a handoff WEP key generation secret parameter is provided to a first and a second access point. Both access points generate a handoff WEP key as a function of the handoff WEP key generation secret parameter and an address of a wireless terminal. The first access point transmits the handoff WEP key to the wireless terminal. The second access point communicates data packets encrypted with the handoff WEP key with the wireless terminal.

Abstract: The invention relates to a method for a handover of a mobile node from a non-3GPP to a 3GPP network, and of a mobile node, which is located in a non-3GPP/ 3GPP network. The handover is improved by discovering an appropriate MME and registering the mobile node at the discovered MME, in advance . This includes to first determine the location of the mobile node in the non-3GPP network, so as to be able to detect an MME in the vicinity of the mobile node's location. The 3GPP contexts are then transmitted to the new MME before the handover is performed. Moreover, the invention teaches to change the Serving-Gateway in the 3GPP network before performing a handover, thereby accelerating the handover. When a handover gets likely, the mobile node's location is determined and a new Serving-Gateway is selected. The data path is changed to go via the new Serving-Gateway.

Abstract: Spectrum handoff is an indispensable component in cognitive radio networks to provide resilient service for the secondary users. In this paper, we explore the spectrum handoff procedure and then propose four metrics to characterize both short-term and long-term spectrum handoff performance: link maintenance probability, the number of spectrum handoff, switching delay, and non-completion probability. In particular, the probability mass function (pmf) and the average number of spectrum handoff are developed. The tele-traffic parameters are relaxed to follow a general distribution function, which will enable a wide applicability and theoretical significance of the derived formulae. Both opportunistic and negotiated spectrum access strategies are investigated. Results show that these two mechanisms will generate significantly different performance. Numerical examples are presented to demonstrate the performance trade-off and the interaction between the primary users and the secondary users. The impact of key parameters on spectrum handoff is also discussed. The techniques as well as the results are important for evaluating the primary and second users co-existence, and hence helpful for design and optimization of cognitive radio networks.

Abstract: Access to a femtocell can be controlled as part of handover of a mobile device from macrocell to femtocell. Macro network platform issues a handover (HO) request towards femto network platform and a single virtual femto node, which represents a plurality of femto access points (APs). Location estimate(s) for the mobile device drives selection of a target femto AP. Selection of the target AP results in acceptance of the HO request. The mobile device also can request macro-to-femto (MTF) handover. HO neighbor list(s) is generated by decoding a network-issued identifier for each femto APs in a set of femtocells, and selectively ranking each femto AP based at least on channel quality; access privileges of the mobile device to each of the identified femto APs determines selectivity. Validation of mobile device's access right(s) drives acceptance of the MTF HO request to a top ranked femto AP.

Abstract: Femtocells are low-cost, low-power cellular base stations that are deployed by the end user to supplement macrocellular coverage and provide high data rates in the customer's premises. In femtocell deployments, leakage of the pilot signal to the outside of a house can result in a highly increased signalling load to the core network as a result of the higher number of mobility events caused by passing users. In this paper, a low cost multi-element antenna solution is proposed to reduce the core network mobility signalling over previously published results using a single antenna only. Antenna gain pattern measurements of a prototype with two patches and two inverted F antennas are presented and a corresponding feeder network is discussed. Self-optimization methods are proposed that jointly select an appropriate antenna pattern and optimize the pilot power. This allows to better match the femtocell coverage to the shape of each individual house and results in an improvement of both indoor coverage and core network signalling resulting from mobility events.

Abstract: Femtocell, a small cellular base station in home and small business environment, is an attractive solution for operators to improve indoor coverage and network capacity in 3G networks. However, there are technical problems due to its mass deployment. The paper presents a femtocell architecture for LTE and investigates different handover scenarios. Two mobility management schemes at radio network layer (RNL) are proposed and their signaling cost, complexity, standard impact and application scenarios are also discussed.

Abstract: This paper presents the implementation of a novel seamless indoor/outdoor positioning service for mobile usersThe service is being made available in the Streamspin system(wwwstreamspincom), an open platform for the creation and delivery of location-based services Streamspin seeks to enable the delivery of truly ubiquitous location-based services by integrating GPS and Wi-Fi location fingerprinting The paper puts focus on key aspects of the seamless handover between outdoor to indoor positioning Several different handover solutions are presented,and their applicability is evaluated with respect to positioning accuracy and battery consumption of the mobile device

Abstract: A method for wireless communications is provided. The method includes determining a set of handover parameters that facilitate a handover between cells in a wireless network and analyzing the set of handover parameters. The method includes dynamically adjusting the parameters to mitigate handover failures between the cells.

Abstract: The goal of the network mobility (NEMO) management is to effectively reduce the complexity of handoff procedure and keep the mobile devices connected to the Internet Vehicle is moving so fast that it may cause the handoff and packet loss problems Both of the problems will lower down the throughput of the network To overcome these problems, we propose a novel NEMO protocol for vehicular ad hoc network (VANET) In freeway, since every car is moving in a fixed direction with high moving speed, the car adopting our protocol can acquire IP address from the VANET through vehicle to vehicle communications The vehicle can rely on the assistance of the front vehicle to execute the pre-handoff procedure or it may acquire its new IP address through multi-hop relays from the car on the lanes of the same or opposite direction and thus reduces the handoff delay and maintain the connectivity to the Internet Simulation results have shown that the proposed scheme is able to reduce both handoff delay and packet loss rate

Abstract: The study compared paper-based and electronic-based medical handover with respect to quality of information transfer during hospital out-of-hours shifts, and analysed the caseload burden of the hospital night team. The participants were 1645 hospital patients transferred from the day team to the out-of-hours team over four months in 2006. Quality of information transfer was determined by clinical data handed over within pre-set fields, and caseload burden by the frequency of tasks required at handover. Handover information fields comprised patient's demographics and location, primary diagnosis, current problem, plan of action and primary care team details. Electronic handover achieved a significantly higher number of completed fields than paper-based handover. Blood collection, checking blood and X-ray results, and adjusting fluid balance and intravenous cannulation account for most of the workload during the nightshift. Electronic handover provides better continuity of care than paper-based handover, and redistribution of tasks during working hours would benefit night staff.

Abstract: With the interworking between a cellular network and wireless local area networks (WLANs), an essential aspect of resource management is taking advantage of the overlay network structure to efficiently share the multi-service traffic load between the interworked systems. In this study, we propose a new load sharing scheme for voice and elastic data services in a cellular/WLAN integrated network. Admission control and dynamic vertical handoff are applied to pool the free bandwidths of the two systems to effectively serve elastic data traffic and improve the multiplexing gain. To further combat the cell bandwidth limitation, data calls in the cell are served under an efficient service discipline, referred to as shortest remaining processing time (SRPT). The SRPT can well exploit the heavy-tailedness of data call size to improve the resource utilization. An accurate analytical model is developed to determine an appropriate size threshold so that data calls are properly distributed to the integrated cell and WLAN, taking into account the load conditions and traffic characteristics. It is observed from extensive simulation and numerical analysis that the new scheme significantly improves the overall system performance.

Abstract: Handover prediction has been considered an effective technology for improvement of LTE Handover performance Although not a few techniques have been proposed to achieve this goal including handover preparation based on cross-layer optimization and mobility prediction, the fact is that their gains are not usually so high as their cost To overcome such weaknesses, this paper proposes a simple handover prediction technique which is based on a novel user mobility model to approximate simulation the laws of user mobility actions We develop a user mobility database to assist the mobility prediction based on the user mobility history records The simulation results show that the proposed technique minimizes the number of handovers and lower the ping-pang rate in LTE system

Abstract: Field measurements from the GSM and UMTS networks are analysed in a road traffic information context. The measurements indicate a potentially large improvement using UMTS signalling data compared with GSM regarding handover location accuracy. These improvements can be used to generate real-time traffic information with higher quality and extend the geographic usage area for cellular-based travel time estimation systems. The results confirm previous reports indicating that the technology has a large potential in GSM and also show that the potential might be even larger and more flexible using UMTS. Assuming that non-vehicle terminals can be filtered out, that vehicles are tracked to the correct route and that handovers can be predicted correctly, a conclusion from the experiments is that the handover location accuracy in both GSM and UMTS will be sufficient to estimate useful travel times, also in urban environments. In a real system, these tasks are typically very challenging, especially in an urban environment. Further, it is reasonably established that the location error will be minor for the data obtained from UMTS.

Abstract: Fourth-Generation Wireless Networks: Applications and Innovations presents a comprehensive collection of recent findings in access technologies useful in the architecture of wireless networks. Based on research results from academia and industry, this innovative publication covers cutting-edge findings on topics such as 4G security, mobile technologies, and handover mechanisms.

Abstract: A wireless communication system and handover method for the wireless communication system are provided. A handover method for a wireless communication system including a plurality of femto cells and at least one macro cell within which the femto cells are disposed includes determining, at a Radio Network Controller (RNC), a handover of a terminal to a femto base station based on a measurement report of the terminal and preset handover parameters, sending a radio link setup request message to a femto base station gateway, the radio link setup request message including a uplink scrambling code and an International Mobile Subscriber Identity (IMSI) of the terminal and a Logical Cell Identifier (LCID) of femto base stations reusing frequency of a macro base station, searching, at the femto base station gateway, for femto base stations of which LCIDs match the LCID contained in the radio link setup request message, and performing, when only one LCID-matched femto base station is discovered, the handover of the terminal to the LCID-matched femto base station.

Abstract: A method and apparatus are provided for use in a cellular radio communication system for adjusting a handover parameter. Information is collected regarding actual handovers that have occurred between one or more pairs of cells as well as handover failures. The collected handover information is processed to determine a handover oscillation rate or a handover cost associated with the cell pair. If the handover performance is determined to be acceptable, the determined handover oscillation rate or the determined handover cost is compared with a predetermined target handover oscillation rate or a predetermined target handover cost, respectively. One or more handover parameters associated with at least one of the cells in the cell pair is adjusted based on the comparison.

Abstract: This paper proposes an energy-aware handoff algorithm based on energy consumption measurements of UMTS and 802.11 WLAN networks on an Android mobile phone. The handoff algorithm uses estimation of application traffic size to find the minimum energy cost alternative by comparing the cost of using UMTS with the cost of performing an opportunistic downward vertical handoff to a WLAN and using WLAN for the transfer and the eventual upward vertical handoff back to UMTS. Our experiments show that the energy cost of UMTS is nearly equal to WLAN as a function of transfer time, but for bulk transfers, transferring a byte of data over UMTS can be over a hundred times more expensive than over WLAN. Further, we discovered that the energy cost of the vertical handoff is quite high, comparable to downloading 0.12-0.67 MB of data over UMTS. To calculate the energy cost of data transfers before they take place, we propose and evaluate a distributed traffic estimation mechanism. The mechanism can predict how much data will be transferred due to a user action (i.e. clicking of an URL link). We provide initial results on the accuracy of the mechanism. Finally, we perform a numerical analysis on the the performance of the handoff algorithm and show that it can reduce the energy consumption significantly when compared with simple policies.

Abstract: The invention relates to a method, mobile node and computer-readable medium for establishing (or pre-establishing) a secure tunnel to an ePDG to prepare for a mobile node attachment or handover to another access network. To reduce the delay of a handover or upon attachment of a mobile node to an access network implied by mechanisms to discover a ePDG, the mobile node maintains a reachability list that can be consulted to identify an ePDG or ePDGs that are reachable in the target access network, i.e. to which the mobile node may establish a secure tunnel. If the mobile node can identify a reachable ePDG for a given access network from the reachability list, the mobile node (pre-)establishes a secure tunnel to the ePDG upon attaching to the given access network. In alternative solutions DNS, DHCP or other mechanism can be used to provide the mobile node with information on ePDGs in its vicinity.

Abstract: A mobile communications system is described in which base stations communicate with each other using a Master/Slave protocol to exchange load balancing information that can be used to control the handover of mobile devices amongst neighbouring base stations and/or neighbouring cells. The Master base station requests the Slave base station to provide a load status report to it either at a defined time or periodicity or in response to certain events.

Abstract: A comprehensive solution is provided for multi-carrier scanning and handover operations in OFDM wireless systems. A multi-carrier scanning is any scanning operation that involves multi-carrier radio frequency carriers. In one embodiment, a mobile station communicates with a serving base station over a primary carrier, and performs scanning over one or more determined carriers. A multi-carrier handover is any handover operation that involves multiple radio frequency carriers. In a first embodiment, a break-before-entry (BBE) handover procedure with fast synchronization is provided. In a second embodiment, an entry-before-break (EBB) handover procedure through unavailable intervals is provided. In a third embodiment, EBB handover procedures for both inter-FA and intra-FA using multiple carriers are provided. Finally, in a fourth embodiment, intra-BS handover procedures are provided. The multi-carrier handover procedures may be applied to 2-to-2 or N-to-N carriers handover situation. The overall scanning time and handover interruption time may be reduced through the provided procedures.

Abstract: Techniques, apparatuses, and systems can include determining one or more handover base station candidates for a specific mobile station associated with a serving base station based at least on respective one or more proximities of the one or more handover base station candidates to the serving base station and one or more base station access privileges associated with the mobile station.

Abstract: A method and an apparatus for performing a handover in an evolved universal terrestrial radio access network (E-UTRAN) are disclosed. A wireless transmit/receive unit (WTRU) sends a measurement report to a source evolved Node B (eNB), and receives a handover command from the source eNB. The WTRU initiates reception and processing of a primary broadcast channel (P-BCH) at the target cell after receiving the handover command. The WTRU then sends a random access preamble to the target eNB, receives a random access response from the target eNB, and sends a handover complete message to the target eNB. The reception and processing of the P-BCH may be initiated immediately after receiving the handover command or after sending the handover complete message. The WTRU may apply default configuration or source cell configuration in the target cell until a target cell SFN and/or P-BCH information are acquired.

Abstract: In one aspect, the invention provides an improved procedure for handing over a connection from a source network node to a target network node. In some embodiments, this procedure includes the following steps: (a) receiving, at a gateway, a handover required message transmitted from the source network node; (b) generating, at the gateway, a handover request message in response to receiving the handover required message; and (c) transmitting, from the gateway, the handover request message to the target network node. In another aspect, the invention provides an improved gateway that is configured to intercept and handle handover signaling.

Abstract: This paper proposes an architecture for interworking heterogeneous all-IP networks with an in-depth analysis of its performance. The novelty of this framework is that it freely enables any 3G cellular technology, such as the Universal Mobile Telecommunications System (UMTS) or the CDMA 2000 system, to interwork with a given broadband wireless access (BWA) system, such as the Worldwide interoperability for microwave access (WiMAX) network or the wireless local area network (WLAN) via a common signaling plane. As a universal coupling mediator for real-time session negotiation and management between these dissimilar networks, the IP multimedia subsystem (IMS) has been exploited. The analytical evaluation investigates the behavior of handoff delay, transient packet loss, jitter, and signaling cost during a vertical handoff for the given framework. Finally, an OPNET based simulation platform has been introduced for the verification of the analytical model and results.

Abstract: Handover is a tradition in mental health settings and can occupy a significant amount of time each day, yet the topic has commanded limited attention in the psychiatric literature. Increasing staff changes and growing reliance on casual staff has heightened the need for the effective and efficient transfer of essential information, as staff will often find themselves in settings with unfamiliar patients. In this context, effective and timely handovers are crucial. The aim of this article is to examine handover and consider how it may be used optimally to enhance service delivery. To reduce information loss and increase accuracy, verbal handover could be supplemented with computer-generated patient data. This combination will ensure face-to-face interaction remains and perhaps decrease time spent unproductively. Further research is necessary to evaluate such a handover system.