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.

Performance issues with vertical handovers - experiences from GPRS cellular and WLAN hot-spots integration

Abstract: Interworking heterogeneous wireless access technologies is an important step towards building the next generation, all-IP wireless access infrastructure. We present an experimental study of inter-network mobility between GPRS Cellular and 802.11b-based WLAN hot-spots, and deeply analyze its impact on active transport TCP flows. Our experiments were conducted over a loosely-coupled, Mobile IPv6-based, GPRS-WLAN experimental testbed. Detailed analysis from packet traces of inter-network (vertical) handovers reveals a number of performance bottlenecks. In particular, the disparity in the round trip time and bandwidth offered by GPRS and WLAN networks, and presence of deep buffers in GPRS, can aggravate performance during vertical handovers. This paper, therefore, summarizes practical experiences and challenges of providing transparent mobility in heterogeneous environments. Based on the observations, we propose a number of network-layer handover optimization techniques, e.g. fast router advertisements (RA), RA caching, binding update (BU) simulcasting and layer-3 based soft handovers that improve performance during vertical handovers. The paper concludes with our experiences of migrating TCP connections, thereby also improving application e.g. FTP, Web performance in this environment.

Strategies for handover and dynamic channel allocation in micro-cellular mobile radio systems

Abstract: Microcellular structures are the central means for increasing the network capacity of mobile radio systems. By examining existing dynamic channel allocation algorithms, the authors identify a class of adaptive algorithms best suited for such microcellular environments. Applicable algorithms of this class require intracell handover and are to a large extent decentralized. One new algorithm of this class is introduced and evaluated by means of simulation. The proposed algorithm (DYNINF) has been evaluated with respect to performance criteria such as blocking probability, interference probability, and number of handovers (stability). It is shown that, based on the capacity improvement achieved by microcells, no relevant further improvement of the capacity can be realized, but that the algorithm is very well suited to cope with the problems of microcells, e.g. discrepancies between the network plan and the real situation and heavy variations of the traffic and interference conditions. >

Load sharing control for a mobile cellular radio system

Abstract: In a mobile cellular radio system, load balancing is achieved by moving dynamically the borders between any two cells such that an overloaded cell becomes smaller and the neighboring cell larger. This is achieved by lowering the entering signal strength threshold for handoff to the neighboring cell and/or increasing the entering signal strength threshold for handoff from the neighboring cell. Thresholds are unique for any two cells.

A description of handover processes in an Australian public hospital

Abstract: Handover of patient care has been an ongoing problem within the health care sector. The process remains highly variable and there is a threat to patient safety. Despite the general belief that handover transitions in patient care have become routine, not enough attention or research has been directed at improving this period of care. For this reason there is a need to provide an analysis of the communication processes during handover. A study was conducted of the handover process among doctors during shift changes within a hospital setting. The results suggested a need for process change. Results revealed a handover process which was unstructured, informal and error prone, with the majority of doctors noting that there was no standard or formal procedure for handover. The research found that the majority of hospital doctors recognised the potential benefits of formalising and computerising this process.

An experimental comparison of handover methods.

Abstract: INTRODUCTION With the increase in shift pattern work for junior doctors in the NHS, accurate handover of patient clinical information is of great importance. There is no published method that forms the gold standard of handover and there are large variations in practice. This study aims to compare the reliability of three different handover methods. PATIENTS AND METHODS We observed the handover of 12 simulated patients over five consecutive handover cycles between SHOs on a one-to-one basis. Three handover styles were used and a numerical scoring system assessed clinical information lost per handover cycle. RESULTS After five handover cycles, only 2.5% of patient information was retained using the verbal-only handover method, 85.5% was retained when using the using the verbal with note taking method and 99% was retained when a printed handout containing all patient information was used. CONCLUSIONS When patient information is handed over by the verbal only method, very few facts are retained; therefore, this method should be avoided whenever possible. Verbal handover with note taking is shown to be an effective method of handover in our study, although we accept that this is an artificial scenario and may not reflect the reality of a busy hospital. Nearly all information is retained by the printed handout method but this relies on the handout being regularly updated.