Number Of Unnecessary Handovers Research Articles

RRH-Sector selection and load balancing based on MDP and dynamic RRH-Sector-BBU mapping in C-RAN

Cloud radio access network (C-RAN) is a paradigmatic architecture that supports the tremendous increase in mobile network traffic. Despite the novel advancements that C-RAN offers, a time-varying traffic environment can cause load imbalances, resulting in inefficient resource utilization. Consequently, the network performance can degrade in terms of the blocked users, the number of unnecessary handovers, and the power consumption. This paper presents an RRH-Sector pair selection for new connections and network load-balancing framework that optimizes the network performance and operator reward without affecting the users’ Quality of Service (QoS) in C-RAN. Firstly, the proposed approach selects the best RRH-Sector pair for each new connection demand by considering the user and operator objectives jointly. This decision is based on an algorithm derived from the Markov decision process (MDP). Secondly, the load-balancing problem is addressed via optimization of the RRH-Sector-BBU dynamic mapping formulated as a linear integer-based constrained optimization problem. We compare solutions for this problem obtained by several evolutionary algorithms. Simulation results show that the proposed RRH-Sector selection scheme provides significant gains when compared with the traditional method based on the received signal strength (RSS). Furthermore, the RRH-Sector-BBU mappings obtained by the evolutionary algorithms are compared with the optimal exhaustive search method. The results show that in most cases the proposed models reach the optimum solution for the number of blocked users, the number of handovers, and the BBU power consumption.

Integration of Fuzzy Logic and ABC Algorithm for Optimized Network Selection in Heterogeneous Wireless Environment

Background & Objective: Various Radio Access Technologies are integrated in the next generation of Heterogeneous Wireless Networks. The coexistence of various kinds of wireless access networks ensures high service quality (QoS) for the users. Seamless vertical handover plays a significant role in providing ubiquitous access to users. The ability to select the optimal access network out of available access networks decides the comprehensive performance of the system. A novel scheme: Handoff Urgency Estimator and Target Access Network Selector using Artificial Bee Colony algorithm (HUETANSABC) for deciding the necessity of handover and selection of the best network is proposed in this paper. The objective of the proposed work is to choose the most promising access network out of available coexisting networks for enhancing user experience. Fuzzy logic provides reliable results even when the input parameters are random in nature and can not be defined precisely. Artificial Bee Colony is an effective method for searching and optimization. Proposed system combines best of fuzzy logic and ABC algorithm for timely initiation of vertical handover. To gather the required information for handover, services provided by IEEE 802.21 standard are utilized. Proposed integration of fuzzy logic and the ABC algorithm has resulted in a decreasing number of unnecessary handovers. Methods: The effect of varying context parameters is analyzed using Fuzzy Inference System to estimate the urgency of handover. The optimization of a target access network selection process is achieved using meta-heuristic method. Results: Simulation results on MATLAB indicate that the proposed system performs better than ABC and Multiple Attribute Decision Making (MADM) techniques.

Efficient Handover Approach in 5G Mobile Networks

Femtocell technology has improved cellular coverage and capacity allowing the provision of rich and interactive communication services in current mobile networks. However, this technology suffers from several drawbacks including; increased interference and packet loss, frequent handovers, and high energy consumption. This paper presents a new handover management approach to overcome performance limitations linked to handover taking place at dense femtocell environments. RSSI of Base Station (BS), mobile user’s movement direction, and BS available capacity are factors used in this work to improve handover decision while sustaining perceived network performance. In addition, in order to reduce the complexity and delay of handover process, the proposed approach has redefined handover major phases including; preparation, decision and execution phases. A densely deployed simulated environment representing heterogeneous 4G and 5G architecture was implemented to evaluate the proposed approach. The simulation environment consists of three paths, each path represents a different network and mobility condition including BS distribution, obstacles, UE movement direction and distance. Results confirmed that the proposed handover approach reported an improved performance in terms of handover delay and number of unnecessary handovers. The average number of handovers occurred during all simulation scenarios was 3, also the average handover delay achieved was (55.15 ms). The number of handovers were decreased 30% and handover delay was reduced more than 10 ms comparing to conventional handover approaches such RSS-based. Hence, an improved adoption of handover management into femotocell environment.

Handover Management for D2D Communication in 5G Networks

This study addresses the handover management issue for Device-to-Device communication in fifth-generation (5G) networks. The Third Generation Partnership Project (3GPP) drafted a standard for proximity services (ProSe), also named device-to-device (D2D) communication, which is a promising technology in offering higher throughput and lower latency services to end users. Handover is an essential issue in wireless mobile networks due to the mobility of user equipment (UE). Specifically, we need to transfer an ongoing connection from an old E-UTRAN Node B (eNB) to a new one, so that the UE can retain its connectivity. In the data plane, both parties of a D2D pair can communicate directly with each other without the involvement of the base station. However, in the control plane, devices must be connected to the eNB for tasks such as power control and resource allocation. In the current standard of handover scheme, the number of unnecessary handovers would be increased by the effect of shadowing fading on two devices. More important, the handover mechanism for D2D pairs is not standardized yet. LTE-A only considers the handover procedure of a single user. Therefore, when a D2D pair moves across cell boundaries, the control channels of the two UEs may connect to different base stations and result in increased latency due to the exchange of D2D related control messages. Hence, we propose a handover management scheme for D2D communication to let both parties of a D2D pair handover to the same destination eNB at the same time. By doing so, the number of unnecessary handovers, as well as the handover latency, can be reduced. In the proposed method, we predict the destination eNB of D2D users based on their movements and the received signal characteristics. Subsequently, we make a handover decision for each D2D pair by jointly factoring in the signal quality and connection stability. Expected improvement can be attained, as revealed in the simulation. Unnecessary handover can be avoided. Consequently, both UEs of a D2D pair reside in the same cell and, therefore, result in increased throughput and decreased delay.

An Efficient CoMP-based Handover Scheme for Evolving Wireless Networks

Inter-Cell Interference (ICI) will be one of main problems for degrading the performance of future wireless networks at the cell edge. This adverse situation will become worst in the presence of dense deployment of micro and macro cells. In this context, the Coordinated Muli-Point (CoMP) technique was introduced to mitigate ICI in evolving wireless networks and increase their network performance at the cell edge. Even though the CoMP technique provides satisfactory solutions of various problems at the cell edge, nevertheless existing CoMP handover schemes do not prevent unnecessary handover initialisation decisions. In this paper, a new CoMP-based handover scheme is proposed in order to minimise unnecessary handover decisions at the cell edge in conjunction with signal measurements such as Reference Signal Received Power (RSRP) and Received Signal Received Quality (RSRQ). A combination of calculations of RSRP and RSRQ facilitate a credible decision making process of CoMP mode and handover mode at the cell edge. Typical numerical experiments indicate that by triggering the CoMP mode, the overall network performance is constantly increase as the number of unnecessary handovers is progressively reduced.

NASH: Navigation-Assisted Seamless Handover Scheme for Smart Car in Ultradense Networks

In the vehicular network, the smart car provides variously network services via user equipment (UE). However, the services might be interrupted since the handover procedure of the UE is performed frequently. The existing handover decision schemes in cellular networks are mostly based on received signal strength (RSS) to make the handover decision. However, these schemes suffer from a ping-pong effect and, as a result, perform unnecessary handovers incurring extra signaling overhead and packet loss, which is even more exaggerated in the ultra-dense environment. The failure probability of the handover procedure will increase when the velocity of the car is fast. Therefore, in this paper we propose a navigation-assisted seamless handover (NASH) scheme for reducing unnecessary handovers and the ping-pong effect. NASH uses the massive Multiple Input Multiple Output (MIMO) technique to perform the bicasting scheme and then it utilizes coordination multi-point (CoMP) and carrier aggregation (CA) mechanisms in the handover procedure to avoid the packet loss problem and enhance throughput. Moreover, a dynamic time to trigger (TTT) mechanism is proposed according to the velocity of the car. The simulation results show that the proposed scheme has a better performance in terms of handover latency, packet loss, network throughput, handover failure probability, and the number of unnecessary handovers.

An Enhanced Handover Algorithm in LTE-Advanced Network

The continuous demand for data by the ever increasing data consuming phones and wireless user equipment has necessitated the need for the deployment of densely populated small cells in future generation of cellular networks. To improve the overall capacity of the cellular network, small cells such as Femtocells are currently being deployed in LTE-Advanced network and are found to be a good solution to bandwidth limitation and coverage problems. However, the use of femtocell also comes with a lot of problem especially when they are deployed in a dense and highly mobile user’s environment. Mobile equipment in such environment faces various problems such as frequent and unnecessary handovers, interference between femtocells, interference between femtocell and macrocell, power outage and security issues. In this research, we propose an enhanced handover algorithm that reduce the number of unnecessary handovers in LTE-A networks as well as reducing the number of target femtocells and call blocking probability during handover. To determine the performance of the proposed algorithm, we compared the proposed algorithm with an existing handover algorithm.

A signal fading-aware and data transmission estimation assisted handover mechanism in LTE networks

In Long-Term Evolution (LTE) networks, the connection between user equipment and base station may be lost when the user equipment moves out of the signal coverage by its service base station, therefore results in data loss. This paper proposes a radio signal fading-aware and data transmission estimation assisted handover mechanism in LTE networks in order to decrease the number of unnecessary handovers and data loss rate. Signal fading-aware mechanism is triggered to filter out interfering signal caused by fading in order to obtain the expected signal strength and thereby determine whether handover should be performed. The amount of data loss associated with signal fading is compared with the data loss associated with the handover in order to determine whether the handover procedure should be executed. Thus, if the user equipment performs a handover that is not triggered by signal fading, the handover wait time can be bypassed, whereas in the event of signal fading, handover is performed with the aim of minimising losses in data transmission. Simulation results demonstrate that 30% average handover times and 8% data loss rate are reduced, as compared with standard handover schemes.

Time-of-Stay Estimation-Based Cell Selection Scheme in Multitier Heterogeneous Mobile Networks

A handover (HO) is an important procedure used to maintain connectivity in mobile networks. Nevertheless, it is not sufficient when a user equipment associates with a certain base station for a very short period. In this letter, we propose an estimated time-of-stay-based cell selection (ETCS) scheme to minimize the number of unnecessary HOs that adversely affect the performance of heterogeneous mobile networks. We analyzed the performance of the proposed ETCS scheme and compared it with that of the conventional cell selection scheme. The results show that the ETCS scheme significantly reduces the number of unnecessary HOs. Therefore, we can expect reduced network overhead for system information acquisitions, HO preparations, and mobility managements using the proposed scheme.

IJARCCE - Computer and Communication Engineering

3 Abstract: With technological advances in the telecommunications sector, everyone around the world would like to be connected seamlessly anytime anywhere through the best network. Making a transition from one network to another and moving between heterogeneous networks is not the only problem that worried specialists, scientific and mobile operators; the concern of QoS is as important as the handoff, The requirements like capability of the network, network conditions, handoff latency, power consumption, network cost, and user preferences must be taken into consideration during vertical handoff. Importance of inter working between architecture requires adaptive approaches to implement the vertical handoff mechanism in 4G wireless networks and produce an effective service for the user by considering handover parameters. In this paper, we analyzed the main approaches for vertical handoff to offer a systematic comparison for new researchers. The survey revealed the need for new approach which satisfy the most important requirements and reduce the HO failure probability and the number of unnecessary handover.

Dynamic user equipment‐based hysteresis‐adjusting algorithm in LTE femtocell networks

In long-term evoluation (LTE) femtocell networks, hysteresis is one of the main parameters which affects the performance of handover with a number of unnecessary handovers, including ping-pong, early, late and incorrect handovers. In this study, the authors propose a hybrid algorithm that aims to obtain the optimised unique hysteresis for an individual mobile user moving at various speeds during the inbound handover process. This algorithm is proposed for two-tier scenarios with macro and femto. The centralised function in this study evaluates the overall handover performance indicator. Then, the handover aggregate performance indicator (HAPI) is used to determine an optimal configuration. Based on the received reference signal-to-interference-plus-noise ratio, the distributed function residing on the user equipment (UE) is able to obtain an optimal unique hysteresis for the individual UE. Theoretical analysis with three indication boundaries is provided to evaluate the proposed algorithm. A system-level simulation is presented, and the proposed algorithm outperformed the existing approaches in terms of handover failure, call-drop and redundancy handover ratios and also achieved better overall system performance.

Validation of an improved location-based handover algorithm using GSM measurement data

When a mobile station moves, the path loss and shadow fading contribute to the large-scale variation in the received signal strength. The variation of signal strength caused by shadow fadings is a random process, and handover decision mechanisms based on measurements of signal strength induce the "ping-pong effect." This paper proposes an improved handover algorithm, based on the estimates of location and velocity of the mobile station, to suppress the ping-pong effect in cellular systems. A practical approach based on GSM measurement data is used to estimate the location and velocity of mobile station to identify the correlation among shadowing components. The impact of location errors on handover performance was examined, and the proposed handover algorithm was applied to a real GSM system in urban Taipei city. The results indicate that the number of unnecessary handover can be reduced 18-26 percent by the proposed approach compared to the conventional method, while the signal outage probability remains similar. Besides, the computational complexity of the proposed algorithm is low, and the algorithm does not use a database or lookup table.