Frequent Handoffs Research Articles

Handoffs and Equity: Impact of a Patient Distribution Model on Handoffs for Black Patients.

Hospital medicine patient distribution models (PDM) assign patients to inpatient services on hospital admission. Models balance tradeoffs including patient handoffs, physician wellness, subspecialty care, and other factors to ensure optimal outcomes; however, equity is rarely considered. Handoffs during inpatient care can result in medical error and worse patient outcomes. This study evaluates the impact of a PDM that prioritizes use of specialty care services and an overflow service (OS) during high census on racial inequities in handoff frequency. A single-center retrospective cohort study of inpatient encounters on hospital medicine services from July 2017 to December 2019 was conducted. The primary exposures included being discharged by a general medicine service (GMS) or cared for by an OS. The primary outcome was handoffs per day of stay, analyzed by multivariable regression adjusted for age, gender, race, ethnicity, insurance, discharge from GMS, and care from OS. A total of 4165 inpatient hospitalizations with the majority of their stay on a hospital medicine service were reviewed. Patients discharged by GMS (78.2% vs. 58.1%, p < .001) and cared for by OS (78.7% vs. 67.0%, p < .001) were more likely to identify as Black. Multivariable analysis showed a handoff risk ratio of 1.53 (p < .001) for OS patients and 1.06 (p = .01) if discharged from GMS, but race alone did not significantly affect risk of handoffs. The PDM prioritization drove increased handoffs disproportionately for Black patients. Multivariable analysis showed that race alone did not contribute to increased handoffs suggesting the creation of a systemic bias in patient care.

Optimization of handoff for joint uplink base station association and power control with max‐min fairness in NOMA small‐cell networks

SummaryThe handoff rate and load balancing are two important issues that have a great impact on the spectrum and energy efficiency in the small‐cell networks (SCN). This paper investigates the handoff optimization in SCN with power‐domain non‐orthogonal multiple access (NOMA) that uses successive interference cancelation (SIC), considering the fairness among base stations (BSs). We study the joint base station association and power control problem by considering the motion of mobile users (MUs) and load balancing in the SCNs. Under the maximum allowable transmit power and minimum average‐rate constraints, two optimization problems are formulated using the number of associated MUs, the number of handoffs, and the transmit power of all MUs. The total power consumption minimization and the system‐wide and handoff utility maximization problems are combined into a single‐stage optimization problem through the weighted‐sum method. We solve the formulated problem using a game theory‐based algorithm and primal decomposition theory. The simulation results show that our proposed algorithm can significantly reduce the frequent handoffs and bring a fair power‐controlled BS association in SCN.

Joint Optimization of QoE and Fairness for Adaptive Video Streaming in Heterogeneous Mobile Environments

The rapid growth of mobile video traffic and user demand poses a more stringent requirement for efficient bandwidth allocation in mobile networks where multiple users may share a bottleneck link. This provides content providers an opportunity to jointly optimize multiple users’ experiences but users often suffer short connection durations and frequent handoffs because of their high mobility. In this paper, we propose an end-to-end scheme, VSiM, for supporting mobile video streaming applications in heterogeneous wireless networks. The key idea is allocating bottleneck bandwidth among multiple users based on their mobility profiles and Quality of Experience (QoE)-related knowledge to achieve max-min QoE fairness. Besides, the QoE of buffer-sensitive clients is further improved by the novel server push strategy based on HTTP/3 protocol without affecting the existing bandwidth allocation approach or sacrificing other clients’ view quality. VSiM is lightweight and easy to deploy in the real world without touching the underlying network infrastructure. We evaluated VSiM experimentally in both simulations and a lab testbed on top of the HTTP/3 protocol. We find that the clients’ QoE fairness of VSiM achieves more than 40% improvement compared with state-of-the-art solutions, i.e., the viewing quality of clients in VSiM can be improved from 720p to 1080p in resolution. Meanwhile, VSiM provides about 20% improvement of average QoE.

Eliminating Hands-Off Handoffs: Improvement in Perioperative Handoff Communication With a Multidisciplinary Tool Initiative.

Handoffs between the operating room (OR) and post-anesthesia care unit (PACU) require a high volume and quality of information to be transferred. This study aimed to improve perioperative communication with a handoff tool. Perioperative staff at a quaternary care center was surveyed regarding perception of handoff quality, and OR to PACU handoffs were observed for structured criteria. A 25-item tool was implemented, and handoffs were similarly observed. Staff was then again surveyed. A multidisciplinary team led this initiative as a collaboration. After implementation, nursing reported improved perception of time spent (2.63-3.68, p = .02) and amount of information discussed (2.85-3.73, p = .05). Anesthesia also reported improved personal communication (3.69-4.43, p = .004), effectiveness of handoffs (3.43-3.82, p = .02), and amount of information discussed (4.26-4.76, p = .05). After implementation, observed patient information discussed during handoffs increased for both surgical and anesthesia team members. The frequency of complete and near-complete handoffs increased (40%-74%, p < .001). A structured handoff tool increased the amount of essential information reported during handoffs between the OR and PACU and increased team members' perception of handoffs.

EdAR: An Experience-Driven Multipath Scheduler for Seamless Handoff in Mobile Networks

Multipath TCP (MPTCP) improves the bandwidth utilization in wireless network scenarios, since it can simultaneously utilize multiple interfaces for data transmission. However, with the fast growth of mobile devices and applications, link interruptions caused by handoffs still lead to drastic performance degradation in such scenarios. Typically, a series of packet losses on part of the links will block the transmission of the entire connection when handoff occurs. This paper proposes an Experience-driven Adaptive Redundant packet scheduler (EdAR) for MPTCP, aiming at achieving seamless handoffs in mobile networks. EdAR enables flexibly scheduling redundant packets with an experience-driven learning-based approach in the face of drastic network environment changes for multipath performance enhancement. To enable accurate learning and prediction, both the network environment and the best course of actions are jointly learned via a Deep Reinforcement Learning (DRL) agent, which we design with a hybrid structure to deal with the complexity of system states. Furthermore, both offline and online learning are utilized to allow the agent to adapt to different and changing network environments. Evaluation results show that EdAR outperforms the state-of-the-art MPTCP schedulers in most network scenarios. Specifically in mobile networks with frequent handoffs, EdAR brings 2× improvement in terms of the overall goodput.

A Robust Vertical Handover Authentication Scheme for SDN Based 5G HetNets

The fifth-generation mobile network is the next paradigm that is expected to bring solutions to the problem of the 4G technology. Also, the expectation is to have the fastest, most reliable network access to support huge data traffic and massively connected nodes with low latency and high throughput with the deployment of the 5G. Hence, there are different new technologies to manage, secure, and fulfill the requirements of 5G. However, the environment of 5G will be very heterogeneous that may cause frequent handoff due to small cell deployment where users join and leave frequently.

Performance comparison of successive interference cancellation decoding order for base station association and power control in small cell networks incorporating handoff optimization

The co-channel interference and frequent handoff are two important issues that have a great impact on the spectrum and energy efficiency in the non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) in the small cell networks (SCN). This paper investigates the performance of SIC decoding order based on the users’ channel state information (CSI) and random SIC decoding order under the perfect and imperfect conditions for the handoff optimization in SCNs with NOMA. The effect of SIC decoding order in the joint base station association and power control problem is studied by considering the motion of mobile users (MUs). Two optimization problems are formulated using the number of associated MUs, the number of handoffs, and the transmit power of all MUs, under the maximum allowable transmit power and minimum average-rate constraints. Two objectives are combined into a single-stage optimization problem through the weighted sum method. The formulated problem is solved using a game theory-based algorithm and primal decomposition theory. The simulation results show that changing the SIC decoding order can lead to performance improvement in the uplink NOMA- based SCNs. Also, it is shown that the proposed algorithm can significantly reduce the frequent handoffs in small cell networks.

Eliminating Hands-Off Handoffs: Improvement in Perioperative Handoff Communication with a Multidisciplinary Tool

INTRODUCTION: Handoffs between the operating room (OR) and post-anesthesia care unit (PACU) require high quality information transfer that may be imperfect. We aim to assess and improve perioperative communication with a handoff tool and process. METHODS: Perioperative staff was surveyed regarding perception of handoff quality with a 10-question online survey and PACU handoffs were observed for structured criteria. A 25-item standardized tool was created and implemented over three stages: stakeholder engagement, pre-implementation planning, and implementation with ongoing monitoring and evaluation. Post-implementation handoffs were similarly observed, and staff was again surveyed. Surveys used 5-point Likert scales and narrative comments. Inclusion of essential elements in observed handoffs was quantitatively analyzed. RESULTS: After implementation, frequency of essential handoff items increased, especially intraoperative surgical information. Overall, there was a significant increase in the frequency of handoffs that contained greater than 50% of the 25-items (40% to 74%, p < 0.001). Prior to implementation, nursing, compared to surgical and anesthesia staff, reported lower perceived time spent (2.16 vs 4.19 vs 4.51, p < 0.001) and lower amount of information discussed (2.41 vs 4.23 vs 4.65, p < 0.001) (Figure). After implementation there was improvement in the nursing perceived time spent (2.16 to 3.41, p = 0.02) and the amount of information discussed during handoffs (2.41 to 3.48, p = 0.05).CONCLUSION: A structured handoff tool improves team members’ satisfaction and perceived handoff quality, but only slightly improves the amount of essential information given during handoffs between the OR and PACU.

Coverage Analysis for Cell-Free Massive MIMO High-Speed Railway Communication Systems

In traditional cellular framework, the frequent handoff is one of the main factors that affect the performance of high-speed railway (HSR) communication systems. The cell-free massive multiple input multiple output (MIMO) is proposed as a promising technique for the antenna point (AP) deployment of HSR communication systems. This paper investigates the coverage performance of the cell-free massive MIMO HSR communication systems with multiple APs and multiple users. Initially, the system and channel models are proposed. Based on the established models, the uplink training, uplink data transmission and downlink data transmission are analyzed, respectively. By using the deterministic equivalent analysis, we derive a deterministic signal-to-interference-plus-noise ratio expression for downlink transmission. Then, a tight upper bound on the coverage probability is derived. In the high power regime, the asymptotic coverage performance is also analyzed. Numerical results verify the correctness of the derived theoretical expressions. Moreover, the effects of the downlink transmit power, AP’s antenna number, AP’s density, user number, and channel fading parameter on coverage performance are also discussed.

CSVAG: Optimizing Vertical Handoff Using Hybrid Cuckoo Search and Genetic Algorithm-Based Approaches

One of the primary challenges that wireless technology in the present generation is facing is always best connected (ABC) service. This is possible only when the wireless overlay networks follow a cooperative and coordinated process. Vertical handoff is one such process. Concerning this process, the main challenge is to develop algorithms that take care of optimal connection management with proper resource utilization for uninterrupted mobility. In this paper, we develop a new hybrid cuckoo search (CS) and genetic algorithm (GA) that maximizes the performance of heterogeneous wireless systems in terms of minimizing latency, handover failure probability, and enhancing the throughput. We focus on an optimized simulation framework to demonstrate the advantage of our hybrid model. It can be discerned from the simulation analysis that the proposed hybrid technique increases throughput by 17% and 8% compared to the cuckoo search and genetic algorithms applied individually. The performance of the proposed scheme is promising for applications wherein the handoff mechanisms have to be optimized to control frequent handoffs to further reduce the power consumption of user equipment.

DS2AN: Deep stacked sparse autoencoder for secure and fast authentication in HetNets

AbstractWith the development of wireless communication technologies, providing seamless communication and secured roaming across devices has gained momentum. With 5G building upon and working together with 4G, it promises up to 100 times faster connectivity than 4G, greater bandwidth and extremely low latency. Though this dramatically enhances user experience, it calls for densification of the network by deploying smaller cells. This solution significantly improves network coverage but results in frequent handoffs. With the adoption of newer network technologies, potential new threats are introduced which becomes quite challenging for the industry. For ensuring seamless mobility, an effective handoff mechanism should ensure a secure and fast authentication process. In this article, Deep Sparse Stacked Autoencoder Network (DS2AN), an unsupervised deep learning model has been used to achieve the said objective. In the proposed method, training is done based on number of hidden layers using back propagation algorithm. Once trained, the cost function is minimized in order to achieve fine tuning of DS2AN.Compared with the existing handoff schemes, DS2AN promises a better level of security and a reduction in time required for handoff. Also, DS2AN is used to identify the presence of malicious entities thereby increasing security in the network. The performance of DS2AN algorithm for authentication delay has been evaluated based on communication and computational cost, and the results shows that DS2AN performs better compared to existing techniques.

An Edge Caching Strategy Based on User Speed and Content Popularity for Mobile Video Streaming

Mobile users’ demands to delay-sensitive video streaming media put forward new requirements for mobile networks, such as architecture optimization. Edge caching as a new paradigm is proposed to enhance the quality of service (QoS) for mobile users at the network edge. Due to the limited coverage of edge cache nodes, the frequent handoffs between base stations would aggravate network traffic overhead, resulting in a bad experience of high latency and service interruption when mobile users browse videos. This paper first proposes a three-layer mobile edge network architecture and applied edge caching to video streams to build an efficient caching system. Given the user’s mobility and low latency of mobile video streaming, we propose an edge caching strategy based on user speed and content popularity. Horizontally, the user’s speed affects the spanning area and the buffer size of the cache on edge; vertically, content popularity determines the priority of cached videos. Experimental results demonstrate that our caching strategy outperforms other schemes in terms of the average delay and the cache hit ratio in mobile video streaming scenes compared with the other three classic caching methods.

Handoffs in Radiology: Minimizing Communication Errors and Improving Care Transitions.

Handoffs are essential to achieving safe care transitions. In radiology practice, frequent transitions of care responsibility among clinicians, radiologists, and patients occur between moments of care such as determining protocol, imaging, interpreting, and consulting. Continuity of care is maintained across these transitions with handoffs, which are the process of communicating patient information and transferring decision-making responsibility. As a leading cause of medical error, handoffs are a major communication challenge that is exceedingly common in both diagnostic and interventional radiology practice. The frequency of handoffs in radiology underscores the importance of using evidence-based strategies to improve patient safety in the radiology department. In this article, reliability science principles and handoff improvement tools are adapted to provide radiology-focused strategies at individual, team, and organizational levels with the goal of minimizing handoff errors and improving care transitions.

Mobility Management in Heterogeneous Cellular Networks

This paper has analysed the mobility management schemes in heterogenous cellular networks (HCNs) considering their power consumptions and network selection delays. The HCNs are the key enabler for 5G cellular network to ensure better user connectivity in ultra-dense networks. Large numbers of small cells are deployed under a macro-cell targeting network hot spot. However, ensuring seamless coverage to the mobile subscribers in motion is challenging in such networks. Frequent handoff between the cells with different bandwidth, throughput, latency, and coverage penetrations, significantly increases the signalling overhead in network. In this context, an efficient mobility management scheme plays a key role for the success of HCN technology. In this paper, a detailed behavioural study of mobility management schemes used in HCN has been provided. For mobile users in the network, the power consumption and network selection delay has been evaluated for k-tier architecture of HCN.

Flexible Virtual Cell Design for Ultradense Networks: A Machine Learning Approach

With the ever-growing demand for even higher throughput, ultradense networks (UDNs) are being deployed for the fifth generation (5G) mobile communications. Although massively distributed radio access points (APs) result in a considerable increase in throughput, they also cause some critical problems. When employing a wireless backhaul, the backhaul capacity becomes a limiting factor, which may result in a high packet loss rate. Furthermore, dense deployment of APs leads to more frequent handoffs for mobile user equipments, which results in heavy measurement and signaling overhead. To address the problem of frequent handoffs, virtual cell (VC) has been considered as a promising solution. However, the limited wireless backhaul capacity encountered by inflexible VC design may still result in an intolerable packet loss rate. For a better trade-off between the packet loss rate and the handoff overhead, a machine learning approach for flexible VC design is proposed that leverages particle swarm optimization (PSO) to quickly find the optimal VC solution. To be responsive to the dynamic traffic demand and backhaul capacity of APs, a new parameter called “weighted distance” is employed in the modified K-means algorithm, which is nested in the PSO procedures for master AP selection and VC boundary determination. Compared with an exhaustive search, optimal VC solutions can be found efficiently through considerably fewer iterations. The proposed method is generic and applicable to disparate UDN application scenarios.

Mobility Management in Small Cell Cluster of Cellular Network

The installation of small cells in a 5G network extends the maximum coverage and provides high availability. However, this approach increases the handover overhead in the Core Network (CN) due to frequent handoffs. The variation of user density and movement inside a region of small cells also increases the handover overhead in CN. However, the present 5G system cannot reduce the handover overhead in CN under such circumstances because it relies on a traditionally rigid and complex hierarchical sequence for a handover procedure. Recently, Not Only Stack (NO Stack) architecture has been introduced for Radio Access Network (RAN) to reduce the signaling during handover. This paper proposes a system based on NO Stack architecture and solves the aforementioned problem by adding a dedicated local mobility controller to the edge cloud for each cluster. The dedicated cluster controller manages the user mobility locally inside a cluster and also maintains the forwarding data of a mobile user locally. To reduce the latency for X2-based handover requests, an edge cloud infrastructure has been also developed to provide high-computing for dedicated controllers at the edge of a cellular network. The proposed system is also compared with the traditional 3GPP architecture and other works in the context of overhead and delay caused by X2-based handover requests during user mobility. Simulated results show that the inclusion of a dedicated local controller for small clusters together with the implementation of NO Stack framework reduces the significant amount of overhead of X2-based handover requests at CN.

Base Station Wake-Up Strategy in Cellular Networks With Hybrid Energy Supplies for 6G Networks in an IoT Environment

To reduce carbon footprint, a hybrid energy powered cellular network (HybE-Net) in the Internet-of-Things (IoT) environment is widely sought after. Different from cellular network powered on-grid energy, the base station (BS) wakeup in HybE-Net needs to consider the solar energy of the BS and the traffic load in the network. Thus, in this article, a fuzzy logic-based wakeup strategy is proposed, which comprehensively considers the energy wakeup level and the available network resource ratio. Then, the solar energy states are analyzed mathematically by using the diffusion approximation method. Finally, to prevent BSs from switching frequently between the sleeping and nonsleeping model, the awakening threshold is optimized by the penalty function method. The simulation results demonstrate that in the proposed wakeup strategy, the wakeup threshold based on the energy state is used to avoid the phenomenon of frequent handoff of the BSs, resulting in fewer handoffs. The proposed BS wakeup strategy can be further applied to both the current and sixth-generation (6G) mobile communication networks, which will be powered by other forms of renewable energy and on-grid energy in the future.

Handoff Algorithm Based on Location Prediction in Ultra-dense Heterogeneous Wireless Network

In the ultra-dense heterogeneous wireless network composed of heterogeneous cellular networks and wireless local area networks, vehicle terminals with variable speeds will face more frequent handovers, resulting in the deterioration of user’s Quality of Service (QoS). For the above problems, firstly, the Gauss Markov mobility model is used to predict the position of the vehicle terminal at the next moment, and the candidate network set that meets the terminal service quality is selected to make the intersection with the current candidate network set. Secondly, if the current access network is not in the intersection, the variable-step firefly algorithm is used to find the best network. Thirdly, the terminal that fails to switch due to the prediction error is migrated to the macro cellular to ensure the continuity of communication. Simulation results show that the proposed algorithm can reduce the frequent handoff phenomenon, such as ping pong handoff in the ultra-dense heterogeneous wireless network. Meanwhile, it can improve the user service quality and network throughput.

Hybrid Fuzzy Logic Engine for Ping-Pong Effect Reduction in Cognitive Radio Network

The spectrum is a scarce resource and shall be used efficiently. It is observed that fixed spectrum allocation techniques, currently in use, may not be able to accommodate increased number of users trying simultaneously to access the network. Researches suggest that this problem of spectrum scarcity can be addressed by cognitive radio networks; which permits the dynamic use of spectrum. One of the basic requirements of dynamic spectrum access in cognitive radio network is spectrum handoff. There is an associated issue with frequent spectrum handoffs and that is of the ping-pong ect. The ping-pong ect is caused due to the motion of mobile users between the adjacent cells, thus, initiating unnecessary spectrum handoffs. The purpose of this study is to develop and analyse a system that has the ability to perform cient decision about the execution of spectrum handoffs and in turn reduce the chances of ping-pong ect. Therefore, a fuzzy logic based system has been developed in a cognitive radio WLAN and UMTS environment and handoff is investigated between primary and secondary users. Our proposed hybrid system uses a two-stage fuzzy logic controller to reduce the number of ping-pong handoffs. In the rst stage, the system is designed to control the power of SU and to avoid any interference to PU. In the second stage, the system is designed to take the decision to execute handoff.

Evaluation of Intraoperative Hand-Off Frequency, Duration, and Context: A Mixed Methods Analysis

BackgroundHand-offs in the operating room contribute to poor communication, reduced team function, and may be poorly coordinated with other activities. Conversely, they may represent a missed opportunity for improved communication. We sought to better understand the coordination and impact of intraoperative hand-offs. MethodsWe prospectively audio-video (AV) recorded 10 operations and evaluated intraoperative hand-offs. Data collected included percentage of time team members were absent due to breaks, relationships between hand-offs and intraoperative events (incision, surgical counts), and occurrences of simultaneous hand-offs. We also identified announcement that a hand-off had occurred and anchoring, in which team members not involved in the hand-off participated and provided information. ResultsSpanning 2919 min of audio-video data, there were 74 hand-offs (range, 4-14 per case) totaling 225.2 min, representing 7.7% of time recorded. Thirty-two (45.1%) hand-offs were interrupted or delayed because of competing activities; eight hand-offs occurred during an instrument or laparotomy pad count. Six cases had simultaneous hand-offs; two cases had two episodes of simultaneous hand-offs. Eight hand-offs included an announcement. Seven included anchoring. Evaluating both temporary and permanent hand-offs, one or more original team members was absent for 40.7% of time recorded and >one team member was absent for 20.5% of time recorded. ConclusionsIntraoperative hand-offs are frequent and not well coordinated with intraoperative events including counts and other hand-offs. Anchoring and announced hand-offs occurred in a small proportion of cases. Future work must focus on optimizing timing, content, and participation in intraoperative hand-offs.