Handover Events Research Articles

Implementing an electronic clinical handover system in a university teaching hospital.

Clinical handover is defined as inter-clinician communication occurring at care interfaces. In this study, we analyse the clinical outcomes and physician attitudes associated with the implementation of a electronic clinical handover system in our medical department. The aim of this project was to introduce a reliable, standardised, reproducible method of communicating information regarding inpatients within our medical department. We also sought to assess the attitudes of physicians within our department to medical handover. We designed and implemented an electronic handover template with a protocol to guide staff as to its use. Handover was audited weekly. In addition, we surveyed attitudes of doctors to handover before and after our handover pilot. An average of 32 patients were handed over each week. Compliance with mandatory handover of ICU/CCU patients averaged at 59%. Extrapolating our pilot results for the year would result in approximately 1655 handover events per annum in our department. One hundred percent of physicians surveyed felt that documentation of handover was beneficial, and staff satisfaction with handover improved after initiation of the pilot (81 vs 24%, p=0.000914). While 64% of staff were concerned that typed electronic handover would increase their workload, only 6% of the post pilot survey group felt that it did increase workload significantly. Electronic clinical handover is feasible and practical within the Irish healthcare system. In addition, it was found in our study to be attractive and effective to physicians without increasing their workload.

Trajectory estimation based on mobile network operator data for cellular network simulations

In this paper, we present a framework for estimating trajectories of cellular networks users based on mobile network operator data. We use handover and location area update events of both speech and packet data users captured in the core network of the Austrian MNO A1 to estimate the subscribers’ mobility behavior. By utilizing publicly available data, i.e., environmental information, road infrastructure data, transmitter power ranges and antenna characteristics, our approach allows the estimation of subscriber trajectories for both urban and semi-rural environments with a good accordance to the actual trajectories. Additionally, we present a method to estimate a particular subscriber’s movement velocity, on the basis of mentioned data. Furthermore, we propose a methodology to estimate when a particular user started or ended a speech or packet data session during his journey, based on mobility-related network events. With this, our framework enables the creation of reproducible mobility situations for cellular network simulations at system level.

Packet cache-forward method based on improved Bayesian outlier detection for mobile handover in satellite networks

In this paper, we propose a Packet Cache-Forward (PCF) method based on improved Bayesian outlier detection to eliminate out-of-order packets caused by transmission path drastically degradation during handover events in the moving satellite networks, for improving the performance of TCP. The proposed method uses an access node satellite to cache all received packets in a short time when handover occurs and forward them out in order. To calculate the cache time accurately, this paper establishes the Bayesian based mixture model for detecting delay outliers of the entire handover scheme. In view of the outliers' misjudgment, an updated classification threshold and the sliding window has been suggested to correct category collections and model parameters for the purpose of quickly identifying exact compensation delay in the varied network load statuses. Simulation shows that, comparing to average processing delay detection method, the average accuracy rate was scaled up by about 4.0%, and there is about 5.5% cut in error rate in the meantime. It also behaves well even though testing with big dataset. Benefiting from the advantage of the proposed scheme in terms of performance, comparing to conventional independent handover and network controlled synchronized handover in simulated LEO satellite networks, the proposed independent handover with PCF eliminates packet out-of-order issue to get better improvement on congestion window. Eventually the average delay decreases more than 70% and TCP performance has improved more than 300%.

Clinical handover practices in maternity services in Ireland: A qualitative descriptive study

Objectivethe objective was to examine and describe clinical handover practices in Irish maternity services. Designthe study design incorporated interviews and focus group discussions with a purposive sample of healthcare practitioners working in Irish maternity services. Settingfive maternity hospitals and fourteen co-located maternity units. Participantsmidwives, obstetricians and other healthcare professionals, specifically physiotherapists and radiologists, midwifery students and health care assistants working in maternity services. Findingsthe study participants provided nuanced and differentiated accounts of clinical handover practices, which indicated a general absence of formal policy and training on clinical handover and the practice of midwifery and medical teams holding separate clinical handovers based on their separate, respective needs for transferring information and clinical responsibility. Participants spoke of barriers to effective clinical handover, including unsuitable environments, lack of dedicated time and fatigue during duty shift clinical handover, lack of supportive information technology (IT) infrastructure, and resistance of some staff to the adoption of new technologies to support clinical handover. Key conclusionswhether internal and external to clinical handover events, the barriers to effective clinical handover represent threats to patient safety and quality of care, since effective clinical handover is essential to the provision of safe quality care. Implications for practiceclear and effective communication between collaborating professionals within maternity teams is essential.

Dynamic PCI allocation on avoiding handover confusion via cell status prediction in LTE heterogeneous small cell networks

AbstractIn this paper, we investigate the inbound handover confusion in the two‐tier macrocell‐small cell networks with help of mobility prediction. Instead of studying the mobile user's (MU) movement, we propose an analytical model for the activity status of small cells, which is to exploit the statistical property of inbound handover events that would happen in small cells. We design the cell status prediction algorithm to obtain the optimal prediction outcome of the next status for the small cells. On avoiding the handover confusion, we develop a dynamic allocation approach of physical cell identifier according to the prediction results. We design (i) the cell status prediction‐based strategy, by which the dedicated PCIs will be assigned to the small cells with busy activity status while the other small cells share the public PCIs, and (ii) an integrated strategy in order to fully exploit the usage of PCI. We formulate the preference relation for small cells via reference signal received quality relation integrated with status prediction information using Bayesian average method. Simulation results reveal that the proposed algorithms yield higher accuracy than the conventional methods; in the meantime, handover confusions can be reduced significantly during the inbound handover. Copyright © 2016 John Wiley & Sons, Ltd.

Performance Evaluation for Local Anchor-Based Dual Connectivity in 5G User-Centric Network

Ultra-dense network (UDN) is considered as one of the most promising techniques in achieving the increasingly explosive growth of data rates for future 5G system. However, a large number of small cells lead to the increased cell edges and the rugged inter-cell interference, which cause frequent handover events and more radio link failure. In this paper, a local anchor-based dual connectivity (DC) architecture is proposed for a user-centric network based on the analysis of mobility management challenges of UDN. Under the proposed architecture, the local anchor acts as the master eNodeB (MeNB) with neighboring small cells acting as slave eNodeBs (SeNBs) to provide DC transmission for user-centric service following each user’s movement. Key procedures for mobility management are correspondingly provided and both the MeNBs and SeNBs are selected from the small cells to investigate the potential of them, which are different from the mobility management methods under the traditional cellular architecture. Performance evaluations are conducted under different parameter configurations to evaluate the maximum potential of the proposed scheme. Simulation results show that in our proposed scheme, the handover failure rate shows a maximum decrease of more than 53% and the average user spectrum efficiency achieves an increase of 5% gains over the current LTE system when the user equipment speed is 3 km/h.

Throughput Estimation Based Distributed Base Station Selection in Heterogeneous Networks

Small cells are considered an emerging technology for increasing the potential capacity of cellular networks. However, as the density of infrastructure increases, users have many choices for connection, and therefore, selecting an appropriate base station (BS) becomes an important issue. This study aims to provide an improved user association rule, where each user autonomously chooses the best among all the BSs in the vicinity, while considering their congestion levels. As the first step, an optimization problem is formulated, which emphasizes both the time-varying nature of the wireless channel and fairness among users. On the basis of this formulation, the influence of a specific handover event on system performance is investigated, and then, two versions of the handover frameworks are developed. Simulation results show that the proposed algorithms increase the throughput of every user in the network by 2.8–12% compared to the best conventional scheme. Furthermore, these schemes especially enhance the performance of users having low service quality by 5.0–85%, through efficient utilization of the pre-installed infrastructures.

Enhanced inter‐access service network handover authentication scheme for IEEE 802.16m network

The 802.16m mobile worldwide interoperability for microwave access (WiMAX) standard is the amendment to the 802.16e standard. It introduced high mobility features that enable mobile broadband services at vehicular speeds beyond 120 km/h. However, handover latency in mobile WiMAX may affect real-time application sessions such as VoIP at very high vehicle speed. This makes it imperative to develop fast and secure handover schemes for such very high-speed vehicles. One of the main factors that affect handover performance in 802.16m standard is the delay introduced by the authentication procedure when a mobile user moves between base stations (BSs). In this study, a recently proposed intra-access service network (ASN) handover authentication scheme with privacy preservation is extended to a fast symmetrical key inter-ASN handover authentication scheme that avoids the involvement of third party. The proposed scheme solves the pairwise master key backward and forward security problems and provides mutual authentication between the mobile station (MS) and the target BS during inter-ASN handover event. Finally, the proposed scheme provides MS anonymity and reduces the need to a high-quality tamper-proof device in the BS that was required in the previous scheme.

SINR, RSRP, RSSI and RSRQ Measurements in Long Term Evolution Networks

The four basic Radio Resource Management (RRM) measurements in Long Term Evolution (LTE) system are Channel Quality Indicator (CQI), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Carrier Received Signal Strength Indicator (RSSI). A measurement of channel quality represented by Signal to Interference plus Noise Ratio (SINR) is used for link adaptation along with packet scheduling, whereas RSRP and RSRQ are needed for making handover decision during intra-eUTRAN (evolved Universal Terrestrial Random Access Network) handover in LTE. In this paper, some practical measurement results recorded from a live LTE network of Australia using a commercial measurement tool namely NEMO Handy are analysed to verify the possible relationships among SINR, RSRP, RSSI and RSRQ as well as to evaluate the effects of SNR on throughput. In addition, the intra- eUTRAN handover events occurred during the test period within the test area are studied. The analysis yields some useful information such as: if the SINR is good for a measurement slot, higher throughput is achieved; RSRP and SNR are proportional to each other on average; and lesser is the difference between RSSI and RSRP, better is the RSRQ - each of which is consistent with theory. All the measurement results are evaluated using computer programs built on MATLAB platform.

Cognitive closed access femtocell application using multi-element antenna

In this paper, a cognitive closed access multi-element antenna-specific femtocell protocol is presented. Femtocell is considered as the preeminent solution for indoor coverage in long-term evaluation (LTE) and LTE-advanced networks. The protocol is verified using a patch antenna for LTE network. In a vast deployment of this mini base station, unwanted handover event is considered as the major obstacle. Access control mechanism with coverage-optimized antenna pattern is one of the most promising solution to resolve this obstacle. A previously proposed microstrip four-element femtocell configuration is used to analyze the performance in user categorizing technique for closed access femtocell network. The categorization is performed using multi-layer feed forward network in neural network. The performance of the technique shows an inherent relationship between completeness of training data and error percentage. Sufficiently low error rates can be achieved by presenting about 15 training samples.

Development and validation of a taxonomy of adverse handover events in hospital settings

To develop and validate a taxonomy to classify and support the analysis of adverse events related to patient handovers in hospital settings. A taxonomy was established using descriptions of handover events extracted from incident reports, interviews and root cause analysis reports. The inter-rater reliability and distribution of types of handover failures and causal factors. The taxonomy contains five types of failures and seven types of main causal factors. The taxonomy was validated against 432 adverse handover event descriptions contained in incident reports (stratified random sample from the Danish Patient Safety Database, 200 events) and 47 interviews with staff conducted at a large hospital in the Capital Region (232 events). The most prevalent causes of adverse events are inadequate competence (30 %), inadequate infrastructure (22 %) and busy ward (18 %). Inter-rater reliability (kappa) was 0.76 and 0.87 for reports and interviews, respectively. Communication in clinical contexts has been widely recognized as giving rise to potentially hazardous events, and handover situations are particularly prone to failures of communication or unclear allocation of responsibility. The taxonomy provides a tool for analyzing adverse handover events to identify frequent causes among reported handover failures. In turn, this provides a basis for selecting safety measures including handover protocols and training programmes.

Congestion Control Technique for Wireless Networks

Congestion control in wireless networks has been extensively investigated over the years and several schemes and techniques have been developed, all with the aim of improving performance in wireless net-work. With the rapid expansion and implementation of wireless technology it is essential that the congestion control problem be solved. This paper presents a congestion control schemes which are different in slow start threshold calculation, bandwidth estimation, and congestion window manipulation. A comprehensive comparison of these approaches is given in relation to assumptions, bandwidth estimation, congestion window size manipulation, performance evaluation, fairness and friendliness and improved throughput. I. Introduction The congestion control in wireless networks has been extensively investigated over the years and several schemes and techniques have been developed, all with the aim of improving performance in wireless network. With the rapid expansion and implementation of wireless technology it is essential that the congestion control problem be solved. The Transmission Control Protocol (TCP) has been widely used in today's Internet. The protocol supports reliable data transport by establishing a connection between the transmitting and receiving ends. The transmitter starts a timeout mechanism when sending a packet to the receiver. The transmitter constantly tracks the round-trip times (RTTs) for its packets as a means to determine the appropriate timeout period. At the receiver, each received packet is acknowledged implicitly or explicitly to the transmitter. If the transmitter does not receive an acknowledgment for a given packet when the corresponding timeout period expires, the packet is deemed to be lost and subject to retransmission. A congestion window with dynamically adjusted size is used by the protocol to regulate the traffic flow from the transmitter to the receiver. Although TCP was initially designed and optimized for wired networks, the growing popularity of wireless data applications has lead third generation wireless networks such as CDMA2000 and UMTS networks to extend TCP to wireless communications as well. The initial objective of TCP was to efficiently use the available bandwidth in the network and to avoid overloading the network (and the resulting packet losses) by appropriately throttling the senders' transmission rates. Network congestion is deemed to be the underlying reason for packet losses. Consequently, TCP performance is often unsatisfactory when used in wireless networks and requires various improvement techniques. A key factor causing the unsatisfactory performance is that the radio link quality in wireless networks can fluctuate greatly in time due to channel fading and user mobility 1.1 Problems of TCP in Wireless Scenario TCP protocol may experience performance degradations over wireless networks, due to non-congestion related packet loss and varying round trip times Unmodified standard TCP performs poorly in a wireless environment due to its inability to distinguish packet losses caused by network congestion from those attributed to transmission errors. Packet loss or reception of out of- order packets indicates failures. To remove such failures ,TCP implements flow control and congestion control algorithms based on the sliding window. The performance of TCP is generally lower in wireless networks than in fixed .Thesis explained by the fact that TCP cannot distinguish problems that typically occur in wireless networks from congestion. The congestion control algorithms in TCP are based on the assumptions that data is lost mainly due to congestion and that data loss duet transmission errors is rare .Therefore, data loss is interpreted as a signal of congestion in the network. Even in a wireless network, where data loss may not be related to congestion, TCP considers it as a congestion case.TCP segments may be lost if the radio conditions are poor and the link layer protocol provides a low reliability. After some retransmission attempts the link layer protocol gives up and leaves further error recovery to TCP. Handover events may also lead to data loss. A whole window of data may be lost due to handover. Data loss due to an unreliable link layer or a handover may cause a timeout event followed by slow start or three Daypack followed by fast retransmit and fast recovery. In either case, the congestion control action taken by TCP is unnecessary. Directly after the loss event ,the radio quality may become high again, and after handover data may be transmitted without problems to the new base station.TCP may also misinterpret a sudden increase in the round trip time as data loss. If the delay is long enough for the retransmission timer to expire before an acknowledgments received, then TCP misinterprets the delay as an indication of data loss due to congestion.

Clinical handover as an interactive event: Informational and interactional communication strategies in effective shift-change handovers

Clinical handover -- the transfer between clinicians of responsibility and accountability for patients and their care (AMA 2006) -- is a pivotal and high-risk communicative event in hospital practice. Studies focusing on critical incidents, mortality, risk and patient harm in hospitals have highlighted ineffective communication -- including incomplete and unstructured clinical handovers -- as a major contributing factor (NSW Health 2005; ACSQHC 2010). In Australia, as internationally, Health Departments and hospital management have responded by introducing standardised handover communication protocols. This paper problematises one such protocol - the ISBAR tool - and argues that the narrow understanding of communication on which such protocols are based may seriously constrain their ability to shape effective handovers. Based on analysis of audio-recorded shift-change clinical handovers between medical staff we argue that handover communication must be conceptualised as inherently interactive and that attempts to describe, model and teach handover practice must recognise both informational and interactive communication strategies. By comparing the communicative performance of participants in authentic handover events we identify communication strategies that are more and less likely to lead to an effective handover and demonstrate the importance of focusing close up on communication to improve the quality and safety of healthcare interactions.

A preliminary study of the impact of a handover cognitive aid on clinical reasoning and information transfer

To assess the impact of a written cognitive aid on expressed clinical reasoning and quantity and the accuracy of information transfer during resident doctor handover. This study was a randomised controlled trial in an academic paediatric intensive care unit (PICU) of 20 handover events (10 events per group) from residents in their first PICU rotation using a written handover cognitive aid (intervention) or standard practice (control). Before rounds, an investigator generated a reference standard of the handover event by completing a handover aid. Resident handovers were then audio-recorded and transcribed by a blinded research assistant. The content of this transcript was inserted into a blank handover aid. A blinded content expert scored the quantity and accuracy of the information in this aid according to predetermined criteria and these information scores (ISs) were compared with the reference standard. The same expert also blindly scored the transcripts in five domains of clinical reasoning and effectiveness: (i) effective summary of events; (ii) expressed understanding of the care plan; (iii) presentation clarity; (iv) organisation; (v) overall handover effectiveness. Differences between intervention and control groups were assessed using the Mann-Whitney test and multivariate linear regression. The intervention group had total ISs that more closely approximated the reference standard (81% versus 61%; p<0.01). The intervention group had significantly higher clinical reasoning scores when compared by total score (21.1 versus 15.9 points; p=0.01) and in each of the five domains. No difference was observed in the duration of handover between groups (7.4 versus 7.7minutes; p = 0.97). Using a novel scoring system, our simple handover cognitive aid was shown to improve information transfer and resident expression of clinical reasoning without prolonging the handover duration.

The frequency of CFVD speed report for highway traffic

AbstractThe control signals of cellular networks have been used to infer the traffic conditions of the road network. In particular, consecutive handover events are being used to estimate the traffic speed. During traffic congestion, consecutive handover events may be rare because vehicles move slowly, and thus very few or no speed reports would be generated from the congested area.However, the traffic speed report rate during traffic congestion has not been investigated in the literature. In this paper, we present an analytic model to estimate the speed report rate from cellular network signaling in steady traffic conditions, that is, the traffic speed and flow are assumed constant. Real field trial data were used to validate our analytic model. In addition, computer simulations were conducted to study how speed reports are generated in dynamic traffic conditions when traffic speed and flow change rapidly. Our study indicates that in a typical cell of length 1.5 km with a typical expected call holding time of 1 min, no speed report was generated from a congested three‐lane highway. Our study demonstrates that the lack of speed reports from consecutive handover events during rush hours indicates severe traffic congestion, and new methods that can estimate traffic speed from cellular network data during severe traffic congestion need to be developed. Copyright © 2013 John Wiley &amp; Sons, Ltd.

A Preamble Design Technique for Efficient Handover in IEEE 802.16 OFDM-Based Mobile Mesh Networks

In this paper, a hierarchical design concept of a preamble for orthogonal frequency-division multiplexing (OFDM)-based mobile mesh networks (MMNs) is proposed to reduce the handover overhead by distinguishing an intercluster handover event from an intracluster handover event at the physical layer. The handover procedure using the proposed preamble can simplify the scanning procedure and skip/simplify the network entry procedure, resulting in a significant reduction of the handover overhead. The performance of the handover procedure using the proposed preamble is evaluated using the parameters in the IEEE 802.16 mesh mode.

A context‐aware handover decision based on user perceived quality of service trigger

AbstractGrowing demands for pervasive and ubiquitous services over wireless mobile networks and evolution of such networks towards heterogeneous solutions have emphasized the necessity of more intelligent handoff decisions. The existing handoff management methods in the literature are mostly using signal strength measurements and other link quality evaluations not addressing the knowledge about context of mobile devices, users and networks. Recently, context‐aware handoff management has been considered as a novel candidate for fourth generation (4G) wireless technology. In this paper, user perceived quality of service has been considered in addition to traditional contexts such as user preferences, application requirements, network parameters and link quality for decision making. User perceived quality (UPQ) has been employed as a trigger source, in addition to link layer triggers which are emerged using media independent handover (MIH) event service. This paper presents a policy based mechanism for handoff decision making where fuzzy petri nets (FPNs) have been utilized as its evaluation algorithm. A case study has been provided by simulations to show the usability and user level satisfaction. Simulation results show superior performance in terms of UPQ, jitter and packet delivery measures. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Handover approaches for seamless mobility management in next generation wireless networks

ABSTRACTNext generation wireless networks (NGWN) will be an integration of heterogeneous wireless access networks that will interwork over an IP‐based infrastructure. This all‐IP vision has led to the development of handover mechanisms to support seamless mobility for active network services among the different interworking wireless networks in order to ensure network access ubiquity in NGWN. These handover mechanisms need to ensure that mobile devices continue to receive ongoing communication without any noticeable disruption during handover events among the heterogeneous networks. This paper gives a qualitative and quantitative review of current handover approaches of IP mobility management protocols for NGWN with an objective to introduce a new way of further optimizing the handover performance. In particular, the paper focuses on handover approaches of mobile IPv6 (MIPv6) based mobility management protocols. Thus, the need, benefits, and limitations of these handover approaches are explored. Thereafter, dynamic handover coordination is introduced as a new viable solution that exploits the benefits and mitigates the limitations of these handover approaches hence improving handover performance in terms of handover delay, packet loss, and signaling overhead. Copyright © 2011 John Wiley &amp; Sons, Ltd.

이동 멀티미디어 망을 위한 상호관계기반 자원 할당 방법

모바일 멀티미디어 환경에서 초고속의 서비스를 요구하는 다수의 사용자를 수용하려면 마이크로/피코 셀과 같이 셀의 크기를 더욱 줄여서 무선 자원의 재사용성을 증대시켜야 한다. 특히 멀티미디어 트래픽의 전송 중에 핸드오버가 발생한다면, 멀티미디어 트래픽의 QoS가 지연 및 손실에 의하여 영향 받기 때문에 정지 상태와 동일한 QoS를 유지하기 위하여 효율적인 자원 예약 및 할당 방안이 필요하다. 본 논문에서는 차세대 이동 통신망에서 멀티미디어 서비스의 효율적인 QoS를 제공하기 위한 방안의 하나로서, 수락 제어, 부하 제어 그리고 패킷 스케쥴러와 밀접한 관련성을 갖는 자원 할당 방법을 제안한다. 시뮬레이션을 통하여 제안된 방법의 우수성을 평가한다. It is widely accepted that the coverage with high user densities in mobile multimedia environments can only be achieved with small cell such as micro- and pico-cell. If handover events occur during the transmission of multimedia, the efficient resource reservation and handover methods are necessary in order to maintain the same QoS of transmitted multimedia traffic because the QoS may be defected by some delay and information loss. In this paper, we propose a resource allocation method in the next generation mobile communication systems, in which the resource allocation process has a tight relation with call admission, call load, and packet scheduling. The simulation results show that our proposed method provides a excellent performance.

A cooperative diversity based handoff management scheme

Cooperative diversity has emerged as a promising technique to facilitate fast handoff mechanisms in mobile ad-hoc environments. The key concept behind a prominent cooperative diversity based protocol, namely, Partner-based Hierarchical Mobile IPv6 (PHMIPv6), is to enable mobile nodes anticipate handover events by selecting suitable partners to communicate on their behalves with Mobility Anchor Points (MAPs). In the original design of PHMIPv6, mobile hosts choose partners based on their signal strength. Such a naive selection procedure may lead to scenarios where mobile hosts lose communication with the selected partners before the completion of the handoff operations. In addition, PHMIPv6 overlooks security considerations, which can easily lead to vulnerable mobile hosts and/or partner entities. As a solution to these two shortcomings of PHMIPv6, this paper first proposes an extended version of PHMIPv6 called Connection Stability Aware PHMIPv6 (CSA-PHMIPv6). In CSA-PHMIPv6, mobile hosts select partners with whom communication can last for a sufficiently long time by employing the Link Expiration Time (LET) parameter. To tackle the security issues, the simple yet effective use of two distinct authentication keys is envisioned. Furthermore, to shorten the communication time between mobile hosts and their corresponding partners, a second handoff management approach called Partner Less Dependable PHMIPv6 (PLD-PHMIPv6) is proposed.