Handoff Rate Research Articles

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.

Nursing Handoff Education Using Experiential and Virtual Innovations.

Seventy percent of serious medical errors are the result of ineffective communication, including handoff errors. Nursing students have cited a need for more experience on how to give handoff; yet, handoff education remains variable. Two innovative curricular approaches were implemented on the basis of Bloom's taxonomy to teach handoff education: experiential and virtual. The outcomes of the 2 curricular innovations were evaluated for handoff completion, handoff accuracy, and handoff quality, based on context. During the experiential approach, students demonstrated average handoff completion rates of 84%. During the virtual approach, students' handoff completion rates rose from 25% to 63% and accuracy handoff rates rose from 13% to 31%. Evaluations support that varying educational methods successfully teach nursing students how to give handoffs. Complementary innovations grant educators flexibility to tailor innovations to curriculum and course context, as supported by Bloom's taxonomy.

A novel approach to fairness-aware energy efficiency in multi-RAT heterogeneous networks

Heterogeneous cellular networks are a viable solution in response to the growing demand for broadband services in the new-generation wireless networks. It is more challenging to manage resources (e.g., user association and power control) in multi-radio access technology (multi-RAT) HetNets than in conventional single-tier cellular networks due to the higher computational complexity and energy efficiency constraints. In addition, given the novel services and resource limitation of the user layer, energy efficiency and fairness assurance are critical issues in the uplink. Considering the uplink fairness criterion, this paper proposes a dynamic optimization model which maximizes the total uplink/downlink energy efficiency in addition to providing the essential coverage and capacity of heterogeneous cellular networks. Based on the non-convex characteristics of the energy efficiency maximization model, the mathematical model can be formulated into two subproblems, i.e., resource optimization and user association. In this approach, a subgradient method is applied for fair resource management and also successive convex approximation and dual decomposition methods are adopted to solve the proportional fairness problem. The simulation results exhibit a considerable throughput increase of 25% and 18% on average for random and hotspot user distributions, respectively. Based on the numerical results, the adaptive radio resource management method reduces the rate of vertical handoffs between RATs, which leads to more stable communications for the users. It also proved that the proposed approach managed to significantly improve the total network energy efficiency by up to 40%.

A Conversation-Driven Approach for Chatbot Management

Managing and evolving a chatbot’s content is a laborious process and there is still a lack of standardization. In this context of standardization, the absence of a management process can lead to bad user experiences with a chatbot. This work proposes the Chatbot Management Process, a methodology for content management on chatbot systems. The proposed methodology is based on the experiences acquired with the development of Evatalk, the chatbot for the Brazilian Virtual School of Government. The focus of this methodology is to evolve the chatbot content through the analysis of user interactions, allowing a cyclic and human-supervised process. We divided the proposed methodology into three distinct phases, namely, manage, build, and analyze. Moreover, the proposed methodology presents a clear definition of the roles of the chatbot team. We validate the proposed methodology along with the creation of the Evatalk chatbot, whose amount of interactions was of 22,771 for the 1,698,957 enrolled attendees in the Brazillian Virtual School of Government in 2020. The application of the methodology on Evatalk’s chatbot brought positive results: we reduced the chatbot’s human hand-off rate from 44.43% to 30.16%, the chatbot’s knowledge base examples increased by 160% whilst maintaining a high percentage of confidence in its responses and keeping the user satisfaction collected in conversations stable.

Spectral decision analysis and evaluation in an experimental environment for cognitive wireless networks

Dynamic spectrum allocation is the crucial aspect in Cognitive Radio Networks (CRN) to improve spectral efficiency where the selection of the target frequency channel plays a relevant role in the communication performance of the secondary user. Therefore, the current research work aims to analyze and comparatively evaluate three multi-criteria techniques in spectrum decision within an experimental environment. In order to achieve the above, it is incorporated actual information from licensed users through realistic spectral occupancy data measured in the GSM bands, the performance of the proposed methodology is validated through three multi-criteria decision-making techniques: Multiplicative Exponential Weighting (MEW), Simple Additive Weighting (SAW), and Multi-Criteria Optimization and Compromise Solution (VIKOR). The results obtained show the outstanding performance of the multicriteria algorithms in decision making and their application in cognitive radio networks, highlighting the high performance of the SAW algorithm in contrast to MEW and VIKOR. The contribution of this work is the use of actual spectral occupancy information captured through a spectral measurement campaign in Bogota, the use of three evaluation metrics in terms of handoff rate, bandwidth, and throughput, as well as a detailed analysis of the results obtained.

RWP+: A New Random Waypoint Model for High-Speed Mobility

In this letter, we emulate real-world statistics for mobility patterns on road systems. We then propose modifications to the assumptions of the random waypoint (RWP) model to better represent high-mobility profiles. We call the model under our new framework as RWP+. Specifically, we show that the lengths of the transitions which constitute a trip, are best represented by a lognormal distribution, and that the velocities are best described by a linear combination of normal distributions with different mean values. Compared to the assumptions used in the literature for mobile cellular networks, our modeling provides mobility metrics, such as handoff rates, that better characterize actual emulated trips from the collected statistics.

Evaluation of the performance of a collaborative proposal of multiple access in cognitive radio networks

Cognitive radio networks (CRN) allow for an increase in spectral efficiency and performance of today's wireless networks. Currently, multiple proposals exist in the area of spectral decision-making and mobility; however, very few evaluate the impact of collaboration between secondary users and the performance of spectrum access by many secondary users. Unlike existing works, this article provides a comprehensive quantitative analysis of the performance of CRN taking into account access to the spectrum simultaneously by multiple users and decision making based on collaboration through the exchange of information between nearby secondary users. This proposal is developed through the implementation of four modules: Input Module, Multi-user Module, Collaborative module and Decision-making module, where the results are evaluated comparatively through the handoff rate generated with two multicriteria techniques: Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Multi-Criteria Optimization and Compromise Solution (VIKOR). The evaluation is carried out taking into account three levels of collaboration, three multi-user access scenarios, and two multi-criteria techniques for a total of 18 simulation scenarios. The results obtained show the importance of implementing collaboration strategies, as for multi-user access, the number of handoffs increases as the number of serial users increases. TOPSIS presented the best results in 76 % of the analyzed cases where VIKOR generated a smaller number of handoffs; TOPSIS maintained good performance with differences not exceeding 90 handoffs.

"Increasing Warm Handoffs: Optimizing Community Based Referrals in Primary Care Using QI Methodology".

Social and environmental factors have an outsized effect on one’s health. Children are particularly impacted by the adverse effects of poverty. While social determinants of health (SDH) screening in healthcare settings has proliferated there remain gaps in best practices for screening processes. As research has shown that patient navigation leads to an improvement in unmet social needs and family-reported child health, warm handoffs may be a key factor in assuring that the social needs of families are effectively addressed. Using quality improvement (QI) methods our pediatric clinic worked to increase the warm handoff rate between Community Health Workers (CHWs) and patients with unmet social needs. CHW warm handoff rates increased two-fold over the intervention period. Our results illustrate that QI methods can be used to optimize workflows to increase warm handoffs with CHWs. This is important as health centers work to improve their social needs screening and referral programs.

RETRACTED ARTICLE: Trust and privacy based vertical handoff decision algorithm for telecardiology application in heterogeneous wireless networks

Telecardiology is one of the emerging fields of telemedicine to improve the cardiac patient’s life quality. It uses the information and communication technologies to monitor the cardiac patients by healthcare professionals at distant. The telecardiology system demands for ubiquitous connection to assure promising services. Such a seamless service is provided by heterogeneous wireless technology. But the open network infrastructure of the heterogeneous networks is prone to various security attacks which makes patient privacy susceptible. Therefore, in this paper, the telecardiology system incorporated with Trust and Privacy based Multi-attribute Vertical Handoff decision algorithm towards decide on an best possible association amongst the available alternative candidates based on the patient health condition. Simulation results show enhancement in provisions of handoff rate, reduced blocking probability and improved performance throughput.

Stochastic Geometry Analysis of Sojourn Time in Multi-Tier Cellular Networks

Impact of mobility will be increasingly important in future generation wireless services and the related challenges will need to be addressed. Sojourn time, the time duration that a mobile user stays within a cell, is a mobility-aware parameter that can significantly impact the performance of mobile users and it can also be exploited to improve resource allocation and mobility management methods in the network. In this paper, we derive the distribution and mean of the sojourn time in multi-tier cellular networks, where spatial distribution of base stations (BSs) in each tier follows an independent homogeneous Poisson point process (PPP). To obtain the sojourn time distribution in multi-tier cellular networks with maximum biased averaged received power association, as the first step, we derive the area of contact, based on which we then derive the linear contact distribution function and chord length distribution of each tier. We also study the relation between mean sojourn time and other mobility-related performance metrics. We show that the mean sojourn time is inversely proportional to the handoff rate, and the complementary cumulative distribution function (CCDF) of sojourn time is bounded from above by the complement of the handoff probability. Moreover, we study the impact of user velocity and network parameters on the sojourn time.

Research on the Handoff for Urban Rail Transit Based on IGM-BP Algorithm

Aiming at the problem that the reference signal received power (RSRP) value received by the urban rail transit train during the handoff fluctuates greatly, which causes frequent occurrence of ping-pong handoff, combined with the A3 event in the TD-LTE standard, the improved grey prediction-BP neural network (IGM-BP) algorithm was proposed to improve RSRP fluctuations. The terminal access unit (TAU) will receive the first four sets of RSRP values at time t to establish a grey model GM (1,1) and get a set of predicted values. Take the average of the predicted value as the expected value, and finally the predicted values, modified by the BP neural network algorithm, are used to obtain the expected RSRP value. The simulation results show that the proposed algorithm, compared with the traditional handoff algorithm and the grey prediction algorithm, decreases the RSRP value fluctuation range, reduces the ping-pong handoff rate and meets the requirement that the TD-LTE system handoff success rate reaches 99.5%.

Low Complexity Radio Mobile Speed Estimation Using Count of Received Envelop Peaks and Troughs

Future high densification wireless networks come with high handoff rates, which require knowledge of mobile speed. Mobile speed estimation is crucial for optimizing handover to reduce call drops and network signaling flow, optimize traffic scheduling, improve quality of service, achieve resource optimization, mobility load balancing, channel quality feedback enhancement, and energy efficiency. In this paper, we present a low complexity mobile speed estimation model using count of peaks and troughs of the received signal envelop. We simulated the model in Matlab® and our result shows that the model has a maximum error of 0.25 m/s. The model has two advantages. First, it does not require measurement of the received signal power; it only counts envelop peaks and troughs. Second, the model is independent of DC offset inherent in the radio receivers. However, the model has one limitation—it does not give the crossing component of a mobile’s velocity.

An Overview of Enhance Bandwidth Management in Cellular Network

cellular networks have changed our life. However, current cellular network does not have an efficient bandwidth management during congestion. Some of these techniques was used have a few drawbacks such as the performance of the handoff mechanism depends on the channel quality, QoS, bandwidth, delay and speed of the cellular node, the handoff optimizing tend to increase the ping-pong handoff rate, frequency and bandwidth. The paper indicates the promising factors of the handoff mechanisms as decrease delay, enhance speed, saving energy and control bandwidth to achieve better throughput in wireless networks as compared to predecessor networks. How limited bandwidth are segregated among nodes is discussed in details in this paper. We believe that having implemented the proposed enhanced bandwidth management, congestion in current cellular network can perform better.

An improved vertical handoff decision based on the modular neural network with fuzzy logic for wireless heterogeneous network

In recent times, provision of required services to consumers on an anyplace any time basis is limited by several constraints one among which is the issue of call drop. In order to eliminate this situation, the network operator should enhance vertical handoff (VHO) mechanism. VHO is the process of exchanging the ongoing wireless link to any of the wireless technologies in heterogeneous to support node mobility without fail. Normally, a mobile user can achieve VHO process by utilising the received signal strength (RSS) as single criteria. But sometimes it leads to abortive handoff, service disruption and unbalanced network load. In this paper, a modified modular neural network into fuzzy logic (MNN-FL) by using multi criteria metrics in the mobile environment is proposed. State of mobile terminal (MT) is evaluated by fuzzy logic (FL) by comparing the battery level and the mobility of MT in which identification of best access network is achieved. The high value SNRs are considered for choosing the best network access to accomplish higher data rates and throughput. The performance results demonstrates that MNN-FL-based VHDA shows well-organised network concert in terms of handoff dropping rate and enhanced throughput than existing VHO algorithms.

Trust and Privacy Based Authentication Method for Vertical Handoff Decision in Heterogeneous Network

Next generation wireless networks involve diverse wireless access technologies to support multimedia services to the roaming users with different Quality of Service constraints at anytime and anywhere. The increased number of users and service providers in the integrated network architecture requires authentication mechanism between communication entities to ensure secured handover. The existing security standards of each network are not able to provide most favorable security requirements of the heterogeneous networks because of independent and incompatibility of various wireless networks. Therefore, Trust and Privacy based Multi-attribute Vertical Handoff (TPMVHO) decision algorithm along with Hybrid Genetic Cuckoo Search algorithm to optimize the attributes weight is proposed to select an optimal network for secure handoff mechanism. Simulation results show the reduction in handoff rate, blocking rate and enhanced throughput against Improved Particle swarm optimization based Multi-attribute Vertical Handoff (IPMVHO).

Fundamentals of Mobility-Aware Performance Characterization of Cellular Networks: A Tutorial

This paper provides a tutorial on mobility-aware performance analysis of cellular networks considering both the spatially random [where base stations (BSs) are deployed according to a homogeneous point process] and deterministic grid-based network deployment topologies. We first provide a summary of users’ mobility models with no spatiotemporal correlations (e.g., random walk, random way point, and random direction), with spatial correlations (e.g., pursue mobility and column mobility), and with temporal correlations (e.g., Gauss–Markov and Levy flight). The differences among various mobility models, their statistical properties, and their pros and cons are presented. We then describe two primary approaches (referred to as trajectory-based and association-based approaches) for mobility-aware performance analysis of both random and deterministic cellular networks. For the first approach (which is more general but less tractable than the other approach), we describe a general methodology and present several case studies for different cellular network tessellations, such as square lattice, hexagon lattice, single-tier, and multi-tier models in which BSs follow a homogeneous Poisson point process (PPP). For the second approach, we also outline the general methodology and highlight some limitations/imperfections of the existing techniques and provide corrections to these imperfections. For both of these approaches, we present selected numerical and simulation results to calibrate the achievable handoff rate and coverage probability in various network settings. Finally, we point out specific emerging fifth generation (5G) cellular wireless applications where the impact of mobility would be significant and outline the challenges associated with mobility-aware analysis of those network applications.

Millimetre wave frequency band as a candidate spectrum for 5G network architecture: A survey

In order to meet the huge growth in global mobile data traffic in 2020 and beyond, the development of the 5th Generation (5G) system is required as the current 4G system is expected to fall short of the provision needed for such growth. 5G is anticipated to use a higher carrier frequency in the millimetre wave (mm-wave) band, within the 20 to 90 GHz, due to the availability of a vast amount of unexploited bandwidth. It is a revolutionary step to use these bands because of their different propagation characteristics, severe atmospheric attenuation, and hardware constraints. In this paper, we carry out a survey of 5G research contributions and proposed design architectures based on mm-wave communications. We present and discuss the use of mm-wave as indoor and outdoor mobile access, as a wireless backhaul solution, and as a key enabler for higher order sectorisation. Wireless standards such as IEE802.11ad, which are operating in mm-wave band have been presented. These standards have been designed for short range, ultra high data throughput systems in the 60 GHz band. Furthermore, this survey provides new insights regarding relevant and open issues in adopting mm-wave for 5G networks. This includes increased handoff rate and interference in Ultra-Dense Network (UDN), waveform consideration with higher spectral efficiency, and supporting spatial multiplexing in mm-wave line of site. This survey also introduces a distributed base station architecture in mm-wave as an approach to address increased handoff rate in UDN, and to provide an alternative way for network densification in a time and cost effective manner.

Optimizing Cluster Size Through Handoff Analysis in User-Centric Cooperative Wireless Networks

User-centric base station (BS) cooperation has been regarded as an effective solution for improving network coverage and throughput in next-generation wireless systems. However, it also introduces more complicated handoff patterns, which may potentially degrade user performance. In this paper, we aim to theoretically quantify the tradeoff between handoff cost and data rate. Two user-centric clustering modes are investigated: number-based cooperation (NBC), which is easier to implement, and distance-based cooperation (DBC), which gives higher data rate performance. In the NBC mode, a user is served by its $K$ closest BSs, while in the DBC mode, it is served by all BSs within a given distance. However, due to the randomness of network topology, it is a challenging task to track handoffs and to characterize data rates. To address this issue, we propose a stochastic geometric analysis framework on user mobility, to derive a theoretical expression for the handoff rate experienced by an active user with arbitrary movement trajectory. Then, we characterize the average downlink user data rate under a common non-coherent joint-transmission scheme, which is used to illustrate the tradeoff between handoff rate and data rate in optimizing the cooperative cluster size. We conclude that in the NBC (resp. DBC) mode, the optimal cluster size is asymptotically inversely (resp. inversely) proportional to the square of the user speed and asymptotically inversely (resp. inversely) proportional to the BS intensity. Finally, computer simulation is conducted to validate the correctness and usefulness of our analysis.

A Novel Call Admission Control Algorithm for Next Generation Wireless Mobile Communication

Wireless communication technology is progressing very vastly. With this change in technology customer services for multimedia and non-multimedia are increasing day by day. But due to limited resources of the wireless network, we need to design an efficient CAC algorithm to enhance QoS levels for end users. The Quality of service (QoS) enhancement in the wireless network is related to making an efficient use of current network resources and the optimization of the users. Call acceptance in CAC is one of the challenge in mobile cellular networks to ensure that the acceptance of a new call into a resource limited wireless network should not deviate the service level Agreement (SLAs) at the time of conversations. In the next generation wireless network, CAC has the direct impact on QoS for user calls & overall system performance. To handle handoff calls and new calls in cellular network channel reservation scheme have been already proposed to reserve system bandwidth for higher priority call for CAC. This earlier proposed scheme is not as per the required level of satisfaction because the available reversed bandwidth is not allocated properly in case of least handoff rate. In this, the authors like to present a new channel borrowing scheme where new non real time (NRT) calls can make use of reserved channels. It can borrow this reserved channel on a temporary basis and after this immediately if any handoff call enters the current cell and no any other channels are available, then it will pre-empt the channel from an earlier borrowed NRT user if exists. This pre-empted NRT call is kept in the priority queue to consider its service when any channel becomes free. The number of NRT calls in the queue should not be large to avoid delayed service. The fundamental objective of the proposed scheme to design of the system for evaluating the results and comparing with the results of the existing system. From the results of current research work, it is observed that proposed scheme decreases call dropping probability which increase slightly in call blocking rate over high-density handoff call rate.

Modeling and Analysis of Channel Holding Time and Handoff Rate for Packet Sessions in All-IP Cellular Networks

It is essential to model channel holding time (CHT), cell residence time (CRT), and handoff rate for performance analysis and algorithm evaluation in mobile cellular networks. The problem has been extensively studied in the past for circuit-switched (CS) cellular networks. However, little research has been done on packet-switched (PS) cellular networks. Unlike that a call occupies a dedicated channel during its whole lifetime in CS networks, an active session in PS networks occupies and releases channels iteratively due to discontinuous reception (DRX) mechanism. In this paper, we investigate the key quantities in PS cellular networks. We present a set of comprehensive new models to characterize the quantities and their relationship in PS networks. The models shed light on the relationship between CHT and CRT and handoff rate. The analytical results enable wide applicability in various scenarios and therefore have important theoretical significance. Moreover, the analytical results provide a quick way to evaluate traffic performance and system design in PS cellular networks without wide deployment, which can save cost and time.