Handover

About: Handover is a research topic. Over the lifetime, 24219 publications have been published within this topic receiving 296416 citations. The topic is also known as: handoff.

Electronic software significantly improves quality of handover in a London teaching hospital

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.

Performance evaluation of crossover switch discovery algorithms for wireless ATM LANs

Abstract: In a connection-oriented wireless LAN, the mobility of mobile hosts results in the establishment and disconnection of new and old virtual circuits. The resulting increase in signalling traffic along with the need to support multimedia stream handovers demand a fast, continuous and bandwidth-efficient handover protocol. We adopt a handover scheme based on partial re-establishments, where a new partial path converges to an existing path. Connection rerouting (CR) operations are then performed at the convergence/crossover switch (CX). To achieve localised handovers, a wireless cell clustering scheme is proposed. The clustering of base stations to cluster switches (CLSs) provides fast intra-cluster handovers since the CR operations are performed at the CLS. To support fast inter-cluster handovers, four CX discovery schemes (loose select, prior path, distributed hunt and backward tracking) are introduced. Simulation results obtained from a trace-driven mobile network simulator on four different network topologies (random, star, tree and hierarchical redundancy) reveal that both prior path and distributed hunt discoveries outperform the others by providing the fastest convergence with shorter resulting paths and higher circuit reuse efficiency.

Adaptive Hysteresis Margin for Handover in Femtocell Networks

Abstract: The challenge of elimination of redundant handovers is getting more significant while femtocells with small radius are deployed in networks. The utilization of the femtocells results to more frequent initiation of a handover procedure. This paper focuses on an adaptation of actual level of hysteresis margin according to the position of the user in a cell. The hysteresis margin is commonly used parameter for elimination of redundant handovers. The purpose of this paper is to propose mechanism with minimum requirements on conventional network and user’s equipment and with a simple implementation. Evaluations of proposal in term of efficiency of the redundant handovers reduction as well as an impact on the user’s throughput in 4G wireless networks are carried out. The results show significant reduction of the amount of handovers while reducing the impact on the throughput.

Performance Analysis of Fast Handover in Mobile IPv6 Networks

Abstract: The Fast Handover protocol [1] provides seamless handover in wireless IP networks by minimizing handover latency. To reduce handover latency and to provide faster handover, Fast Handover uses anticipation based on layer 2 (L2) trigger information. Therefore, it incurs higher signaling costs compared with the basic Mobile IP protocol. Furthermore, since the L2 trigger is based on fluctuating wireless channel states, the handover anticipation using the L2 trigger may sometimes be incorrect. In the case of incorrect anticipation, unnecessary buffer space may be used for the purpose of providing a smooth handover. Therefore, it is essential to analyze these overhead costs, in order to evaluate and compare the performance of Fast Handover with that of the basic Mobile IP protocol. In this paper, we analyzed the overhead associated with Fast Handover including the signaling cost and the packet delivery cost. We formulated these costs based on a timing diagram and compared Fast Handover with basic Mobile IPv6 in terms of their packet loss rates and buffer requirements. Also, we studied the impact of the L2 triggering time on the total overhead cost. As a result, we found that the L2 triggering time is an important factor to consider in the optimization of handover performance.

Operations of cellular communications systems based on mobility and teletraffic statistics collected by mobile units

Abstract: Each mobile unit in a cellular communications system accumulates at least one mobility or communications traffic (teletraffic) statistic representative of "typical" operation of the mobile unit within the cellular communications system. The mobile units process or collect the statistics and then transmit the aggregate statistics to a microcell or macrocell base station at time of origination of a call to or from the mobile, request for a handoff of a call by the mobile unit or the registration process. Included within the characteristics which can be monitored in accordance with the present invention are the following: cell sojourn time; area sojourn time; call holding times; call throughput; number of previous handoffs in an ongoing call; time periods between two consecutive failed handoffs for the mobile unit; and, the ratio of calls originating from a mobile unit to the number of calls terminating to a mobile unit. The accumulated data representative of these characteristics are utilized by the receiving base station to assign new and handoff calls to a microcell or a macrocell, to prioritize call handling within the cellular communications system and to assign customized customer service areas.