Showing papers on "Handover published in 2014"

Enabling Vertical Handover Decisions in Heterogeneous Wireless Networks: A State-of-the-Art and A Classification

Abstract: Wireless networks are passing through a transition phase for the past few years now and this transition is giving a way towards the convergence of all IP-based networks to form the Next Generation Networks (NGNs). With the proliferation of these networks in daily life, users' needs are also increasing and service operators are offering different services to satisfy their customers for a better grade of service and an elevated quality of experience (QoE). However, a single operator cannot fulfill the huge demands of the users especially, if a user is nomadic. In nomadism, a user traverses number of available networks that might contain cellular or wireless data networks, usually known as heterogeneous wireless networks. These networks offer various services from email to live video streaming depending upon their capacity and nature. During this traversing procedure, a user switches among different networks to satisfy his/her needs in terms of quality of service. This process is commonly known as a vertical handover or handoff (VHO) due to the involvement of heterogeneous wireless networks in it. An extensive work has been carried out in this field in order to fulfill user demands for better QoS and QoE. In this paper, we give a detailed state-of-the-art of these existing vertical handover decision mechanisms that aim at providing ubiquitous connectivity to the mobile users. We have categorized these vertical handover measurement and decision schemes on the basis of their employed techniques and parameters. Also, we present a comprehensive summary of their advantages and drawbacks. This paper gives its readers an overview of the active research initiatives in the area of handover decision making process in heterogeneous wireless networks and identifies the challenges behind the seamless services provisioning during mobility.

A new control plane for 5G network architecture with a case study on unified handoff, mobility, and routing management

Abstract: The tremendous growth in wireless Internet use is showing no signs of slowing down. Existing cellular networks are starting to be insufficient in meeting this demand, in part due to their inflexible and expensive equipment as well as complex and non-agile control plane. Software-defined networking is emerging as a natural solution for next generation cellular networks as it enables further network function virtualization opportunities and network programmability. In this article, we advocate an all-SDN network architecture with hierarchical network control capabilities to allow for different grades of performance and complexity in offering core network services and provide service differentiation for 5G systems. As a showcase of this architecture, we introduce a unified approach to mobility, handoff, and routing management and offer connectivity management as a service (CMaaS). CMaaS is offered to application developers and over-the-top service providers to provide a range of options in protecting their flows against subscriber mobility at different price levels.

Handover Scheme for 5G C/U Plane Split Heterogeneous Network in High-Speed Railway

Abstract: Being a promising technology for fifth-generation (5G) communication systems, a novel railway communication system based on control/user (C/U) plane split heterogeneous networks can provide a high-quality broadband wireless service for passengers in high-speed railways with higher system capacity, better transmission reliability, and less cochannel interference. However, due to its special architecture where the C-plane and the U-plane must be split and supported by a macro Evolved Node B (eNB) and a phantom eNB, respectively, it would suffer more serious handover problem, particularly in intermacrocell handover, which directly degrades its applicability and availability in high-speed railways. Moreover, no technical specification has been released about this network architecture. Therefore, this paper focuses on redesigning and analyzing technical details and handover procedures based on Long-Term Evolution (LTE) specifications to guarantee the proposed system's practicability and generality and its analytical tractability. To resolve the handover problem, this paper proposes a handover trigger decision scheme based on GM(1, $n$) model of the grey system theory. By this scheme, the received signal quality from the $(N + hbox{1})$th measurement report can be predicted from the $N$th measurement period, and the predicted values can be then utilized to make the handover trigger decision. The simulation results show that the proposed scheme is capable of triggering handover in advance effectively and of enhancing handover success probability remarkably.

Dynamic load balancing with handover in hybrid Li-Fi and Wi-Fi networks

Abstract: In this paper, a hybrid network combining visible light communication (VLC) with a radio frequency (RF) wireless local area network (WLAN) is considered. In indoor scenarios, a light fidelity (Li-Fi) access point (AP) can provide very high throughput and satisfy any illumination demands while wireless fidelity (Wi-Fi) offers basic coverage. Such a hybrid network with both fixed and mobile users has the problem of variable user locations, and thus large fluctuations in spatially distributed traffic demand. Generally, a handover occurs in such a method when a user is allocated by the central controller unit to a different AP which is better placed to serve the user. In order to be representative of real deployments, this paper studies the problem of load balancing of a dynamic system where we consider the signalling overhead for handover. We propose a scheme for dynamic allocation of resources to users, where the utility function takes into account both throughput and fairness. The simulation results show that there is a trade off between the aggregate throughput and user fairness when handover overhead is considered. The proposed dynamic scheme always outperforms the considered benchmarks in terms of fairness and can achieve better aggregate throughput in the case of low user density.

Security Analysis of Handover Key Management in 4G LTE/SAE Networks

Abstract: The goal of 3GPP Long Term Evolution/System Architecture Evolution (LTE/SAE) is to move mobile cellular wireless technology into its fourth generation. One of the unique challenges of fourth-generation technology is how to close a security gap through which a single compromised or malicious device can jeopardize an entire mobile network because of the open nature of these networks. To meet this challenge, handover key management in the 3GPP LTE/SAE has been designed to revoke any compromised key(s) and as a consequence isolate corrupted network devices. This paper, however, identifies and details the vulnerability of this handover key management to what are called desynchronization attacks; such attacks jeopardize secure communication between users and mobile networks. Although periodic updates of the root key are an integral part of handover key management, our work here emphasizes how essential these updates are to minimizing the effect of desynchronization attacks that, as of now, cannot be effectively prevented. Our main contribution, however, is to explore how network operators can determine for themselves an optimal interval for updates that minimizes the signaling load they impose while protecting the security of user traffic. Our analytical and simulation studies demonstrate the impact of the key update interval on such performance criteria as network topology and user mobility.

Socio-economic vision graph generation and handover in distributed smart camera networks

Abstract: In this article we present an approach to object tracking handover in a network of smart cameras, based on self-interested autonomous agents, which exchange responsibility for tracking objects in a market mechanism, in order to maximise their own utility. A novel ant-colony inspired mechanism is used to learn the vision graph, that is, the camera neighbourhood relations, during runtime, which may then be used to optimise communication between cameras. The key benefits of our completely decentralised approach are on the one hand generating the vision graph online, enabling efficient deployment in unknown scenarios and camera network topologies, and on the other hand relying only on local information, increasing the robustness of the system. Since our market-based approach does not rely on a priori topology information, the need for any multicamera calibration can be avoided. We have evaluated our approach both in a simulation study and in network of real distributed smart cameras.

A Learning-Based QoE-Driven Spectrum Handoff Scheme for Multimedia Transmissions over Cognitive Radio Networks

Abstract: Enabling the spectrum handoff for multimedia applications in cognitive radio networks (CRNs) is challenging, due to multiple interruptions from primary users (PUs), contentions among secondary users (SUs), and heterogenous Quality-of-Experience (QoE) requirements. In this paper, we propose a learning-based and QoE-driven spectrum handoff scheme to maximize the multimedia users' satisfaction. We develop a mixed preemptive and non-preemptive resume priority (PRP/NPRP) M/G/1 queueing model for modeling the spectrum usage behavior for prioritized multimedia applications. Then, a mathematical framework is formulated to analyze the performance of SUs. We apply the reinforcement learning to our QoE-driven spectrum handoff scheme to maximize the quality of video transmissions in the long term. The proposed learning scheme is asymptotically optimal, model-free, and can adaptively perform spectrum handoff for the changing channel conditions and traffic load. Experimental results demonstrate the effectiveness of the proposed queueing model for prioritized traffic in CRNs, and show that the proposed learning-based QoE-driven spectrum handoff scheme improves quality of video transmissions.

Analytic Evaluation and Experimental Validation of a Network-Based IPv6 Distributed Mobility Management Solution

Abstract: Mobile Internet traffic is growing steeply, mainly due to the deployment of new broadband wireless technologies and the ever increasing connectivity demand coming from new services being available to mobile users. Current mobile network architectures rely on centralized mobility protocols which intrinsically pose enormous burdens on the central anchors, both in terms of connectivity needs and user mobility management. In order to face these issues, a new paradigm, called Distributed Mobility Management, is being explored, based on flattening the network architecture by deploying multiple mobility anchors at the edge of the network. In this article we conduct an analytic and experimental evaluation of a network-based IP distributed mobility management solution that leverages Proxy Mobile IPv6 protocol operations. We develop an analytic model of the signaling and packet delivery costs, as well as the handover latency of both Proxy Mobile IPv6 and our distributed solution. We have also implemented a Linux-based prototype of our proposal, which has been used to experimentally assess the handover latency in a real IEEE 802.11 scenario. Finally, we use the results obtained from the analytic and experimental performance to evaluate the benefits that could be achieved by deploying a distributed mobility management solution.

Towards understanding TCP performance on LTE/EPC mobile networks

Abstract: The popularity of smartphones and smartphone applications means that data is the dominant traffic type in current mobile networks. In this paper we present our work on a systematic investigation into facets of the LTE/EPC architecture that impact the performance of TCP as the predominant transport layer protocol used by applications on mobile networks. We found that (1) load increase in a cell causes dramatic bandwidth reduction on UEs and significantly degrades TCP performance, (2) seamless handover causes significant TCP losses while lossless handover increases TCP segments' delay.

OpenNet: A simulator for software-defined wireless local area network

Abstract: This study is motivated by a plan to install a software-defined wireless local area network (SDWLAN) on campus, which possesses a desired property that both data flow and device behaviors can be software-definable. Because the installation involves hundreds of access points, we must conduct simulations beforehand to verify the design and scalability of the target system. However, existing SDN simulator like Mininet does not support modeling of wireless channel and mobility. On the other hand, common network simulator like ns-3 only has limited support for software-defined controllers and does not fully implement handover process. We thus develop OpenNet, which connects Mininet to ns3 to enjoy both Mininet's advantage of controller compatibility and ns-3's ability in the wireless/mobility modeling. OpenNet also complements ns-3 by adding probe mechanism, which is missing in the current ns-3 implementation. Our simulation result demonstrates the effectiveness of OpenNet.

Cellular communication system, method for inter-cell handover of terminal and macro base station

Abstract: The present invention discloses a cellular communication system, an inter-cell handover method for a UE, and a macro base station. The cellular communication system includes a macro base station and at least one micro base station within coverage of the macro base station. The macro base station is configured to: establish a control channel for a UE served by the micro base station; perform an access management operation for the UE served by the micro base station within the coverage of the macro base station; and receive a handover request of the UE and hand over the UE to another micro base station within the coverage of the macro base station. The micro base station is configured to establish a data channel for the accessed UE and perform data transmission with the UE. With the present invention, the control plane of the user served by the micro base station can be separated from the data plane of the user, so that the resources of the micro base station can be better used for data communication. Hence, the negative impacts on the system which are caused by the coexistence of macro cells and micro cells in the networking can be reduced.

Handover management in SDN-based mobile networks

Abstract: In this paper we discuss the evolution of mobility management mechanisms in mobile networks. We emphasize problems with current mobility management approaches in case of very high dense and heterogeneous networks. The main contribution of the paper is a discussion on how the Software-Defined Networking (SDN) technology can be applied in mobile networks in order to efficiently handle mobility in the context of future mobile networks (5G) or evolved LTE. The discussion addresses the most important problems related to mobility management like preservation of session continuity and scalability of handovers in very dense mobile networks. Three variants of SDN usage in order to handle mobility are described and compared in this paper. The most advanced of these variants shows how mobility management mechanisms can be easily integrated with autonomie management mechanisms, providing much more advanced functionality than is provided now by the SON approach. Such mechanisms increase robustness of the handover and optimize the usage of wireless and wired mobile network resources.

FBMIS: A Fuzzy-Based Multi-interface System for Cellular and Ad Hoc Networks

Abstract: Several solutions have been proposed for improving the Quality of Service (QoS) in wireless cellular networks, such as Call Admission Control (CAC) and handover strategies. However, none of them considers the usage of different interfaces for different conditions. In this work, apart from using only Base Stations (BSs) as an important device of cellular networks, we propose a multi-interface approach in order to avoid BS overloads and improve the QoS of wireless communications. We propose a system, where each node is equipped with two interfaces: the traditional cellular network interface and Mobile Ad hoc Networks (MANET) interface. The main difficulty for this system is how to choose the right interface in order to guarantee a minimal usage of network resources and at the same time keeping the communication performance in a satisfactory level. For this purpose, in this paper we propose a Fuzzy-Based Multi-Interface System (FBMIS), where each node is able to switch from cellular to Ad hoc and vice versa. We consider three input parameters and one output parameter. From the simulation results, our system shows a good performance.

Call Admission Control based on Adaptive Bandwidth Allocation for Wireless Networks

Abstract: Provisioning of Quality of Service (QoS) is a key issue in any multi-media system. However, in wireless systems, supporting QoS requirements of different traffic types is more challenging due to the need to minimize two performance metrics - the probability of dropping a handover call and the probability of blocking a new call. Since QoS requirements are not as stringent for non-real-time traffic types, as opposed to real-time traffic, more calls can be accommodated by releasing some bandwidth from the already admitted non-real-time traffic calls. If we require that such a released bandwidth to accept a handover call ought to be larger than the bandwidth to accept a new call, then the resulting probability of dropping a handover call will be smaller than the probability of blocking a new call. In this paper we propose an efficient Call Admission Control (CAC) that relies on adaptive multi-level bandwidth-allocation scheme for non-real-time calls. The scheme allows reduction of the call dropping probability along with increase of the bandwidth utilization. The numerical results show that the proposed scheme is capable of attaining negligible handover call dropping probability without sacrificing bandwidth utilization.

Dynamic point selection for LTE-advanced: Algorithms and performance

Abstract: Dynamic Point selection (DPS) is a key Downlink (DL) Coordinated Multipoint (CoMP) technique that switches the serving data Transmission Point (TP) of a User Equipment (UE) dynamically among the UE's cooperating set of TPs without requiring a cell handover. It provides performance improvement due to TP selection-diversity gains and dynamic UE load balancing benefit. In this paper, we propose two simple DPS schemes that take into account the UE's current channel conditions and the cell loading conditions to make the UE's TP switching decisions. We show that these schemes improve the system performance under different practical and realistic settings, such as, cell handover margin, TP switching periods, bursty traffic conditions, and cooperation cell cluster sizes.

Handoff procedure in a mobile communication system

Abstract: The invention relates to an improved handover procedure for a mobile terminal. Under control of the target base station, the mobile terminal is to perform a handoff to a target base station, wherein it is to be configured for communication with the target base station via a target radio cell comprising a downlink carrier and an uplink carrier. The mobile terminal receives a handoff command message for the handoff to the target base station including a handoff execution condition as trigger for executing handoff to the target base station. Then, the mobile terminal determines, based on the received handoff execution condition, whether or not the mobile terminal is to trigger execution of the handoff to the target base station. In case the mobile terminal determines that it is to trigger execution of the handoff to the target base station, the mobile terminal executes the handoff to the target base station.

An Optimized Network Selection and Handover Triggering Scheme for Heterogeneous Self-Organized Wireless Networks

Abstract: Optimizing the balance between different handover parameters for network selection is one of the challenging tasks for seamless communication in heterogeneous networks. Traditional approaches for network selection are mostly based on the Receive Signal Strength (RSS) from the Point of Attachment (PoA) of a network. Most of these schemes are suffered from high handover delay, false handover indications, and inappropriate network selection for handover. To address these problems, we present an optimized network selection scheme based on the speed of a mobile node. A mechanism based on two different thresholds on the speed of a Mobile Node (MN) is integrated in the proposed scheme. If the speed of an MN is greater than any of the threshold, the MN performs handover to a particular network. We employ Grey Relational Analysis (GRA) in the proposed scheme to select the best PoA of the selected network. Similarly, to deal with false handover indications, we proposed an optimized handover triggering technique. We compare our proposed scheme with existing schemes in context of energy consumption for scanning, frequent and failed handovers, packet loss ratio, and handover delay. The proposed scheme shows superior performance and it outperforms existing schemes used for similar purpose. Moreover, simulation results show the accuracy and performance of the proposed scheme.

Method and apparatus for performing handover procedure for dual connectivity in wireless communication system

Abstract: A method and apparatus for performing a handover procedure in a wireless communication system is provided. A master eNodeB (MeNB), in dual connectivity, performs a handover decision from a source secondary eNB (SeNB) to a target SeNB, and transmits an offloading request message, which includes contexts of E-UTRAN radio access bearers (E-RABs) to be offloaded and an offloading indication, to the target SeNB. The MeNB receives an offloading request acknowledge message, which includes identifiers (IDs) of E-RABs accepted by the target SeNB, as a response to the offloading request message from the target SeNB, and transmits an offloading mobility indication to a user equipment (UE).

Handoff Rates for Millimeterwave 5G Systems

Abstract: Millimeterwave band is a promising candidate for 5th generation wireless access technology to deliver peak and cell-edge data rates of the order of 10 Gbps and 100 Mbps, respectively, and to meet the future capacity demands The main advantages of the millimeterwave band are availability of large blocks of contiguous bandwidth and the opportunity of using large antenna arrays composed of very small antenna elements to provide large antenna gains The line-of-sight operation requirement in this band, due to its unique propagation characteristics, makes it necessary to build the network with enough redundancy of access points and the users may have to frequently handoff from one access point to another whenever its radio link is disrupted by obstacles In this paper we investigate the handoff rate in such an access network Based on analysis of various deployment scenarios, we observe that, typical average handoff interval is several seconds, although for certain types of user actions the average handoff interval can be as low as 075 sec

Apparatus, system and method of handover of a beamformed link

Abstract: Some demonstrative embodiments include devices, systems and/or methods of handover of a wireless beamformed link. For example, an apparatus may include a wireless communication unit to communicate between a wireless communication node and a mobile device via a beamformed link between the wireless communication node and the mobile device, the wireless communication unit is to determine a handover candidate for handing over the mobile device, based on at least one beamforming parameter of the beamformed link.

Energy efficient network selection using 802.16g based gsm technology

Abstract: Handover is the mechanism that transfers information from one terminal to another as a user moves through the coverage area of a cellular system. Here the Network selection is the handover decision process between various network environments. This handover decision will be either mobile or network initiated. In 2G GSM handover decision method especially concentrates on Received frequency signals (RFS). Upcoming technologies (3G/4G) the number of available networks increase the selection process should evaluate additional factors such as cost, network services, network terminology, system conditions, user and operators performances and needed energy to work in an exceedingly network. In Future networks (IEEE or 4G standards) offer facilities such as network routes, handover routing messages, network and client reports, message exchange with handover triggers and handover negotiation. In this study we have a tendency to discuss the utilization of a cost function to perform associate a network selection exploitation information provided by these standards, such as network coverage or network properties. The efficient function provides flexibility to balance the various factors within the network selection, and our research is focused on rising each seamlessness and energy efficiency of the devices in handovers. We have a tendency to evaluate our approach supported usage scenarios over 2G, 3G and 4G GSM networks. Our results show the optimal networks and handovers were generate appropriate times to increase overall network connectivity as compared to traditional network schemes, at the same time optimizing energy consumption of network devices.

Machine-to-machine (m2m) terminal, base station, method, and computer readable medium

Abstract: A Machine-to-machine (M2M) terminal ( 11 ) comprises a radio communication unit ( 111 ) and a controller ( 112 ). The radio communication unit ( 111 ) is configured to communicate with a base station ( 13 ). The controller ( 112 ) is configured to change at least one of a cell selection operation, a cell reselection operation, and a handover operation according to whether a specific coverage enhancement processing is required or according to whether the specific coverage enhancement processing is supported by at least one of a cell ( 13 ) in which the M2M terminal ( 11 ) camps on and a neighbouring cell ( 14 ) of the cell ( 13 ) which the M2M terminal ( 11 ) camps on. It is thus possible to provide an improved technique for allowing the M2M terminal that is supporting a special coverage enhancement processing for M2M terminals to camp on an appropriate cell.

Clinical handover within the emergency care pathway and the potential risks of clinical handover failure (ECHO): primary research

Abstract: Background and objectives Handover and communication failures are a recognised threat to patient safety. Handover in emergency care is a particularly vulnerable activity owing to the high-risk context and overcrowded conditions. In addition, handover frequently takes place across the boundaries of organisations that have different goals and motivations, and that exhibit different local cultures and behaviours. This study aimed to explore the risks associated with handover failure in the emergency care pathway, and to identify organisational factors that impact on the quality of handover. Methods Three NHS emergency care pathways were studied. The study used a qualitative design. Risks were explored in nine focus group-based risk analysis sessions using failure mode and effects analysis (FMEA). A total of 270 handovers between ambulance and the emergency department (ED), and the ED and acute medicine were audio-recorded, transcribed and analysed using conversation analysis. Organisational factors were explored through thematic analysis of semistructured interviews with a purposive convenience sample of 39 staff across the three pathways. Results Handover can serve different functions, such as management of capacity and demand, transfer of responsibility and delegation of aspects of care, communication of different types of information, and the prioritisation of patients or highlighting of specific aspects of their care. Many of the identified handover failure modes are linked causally to capacity and patient flow issues. Across the sites, resuscitation handovers lasted between 38 seconds and 4 minutes, handovers for patients with major injuries lasted between 30 seconds and 6 minutes, and referrals to acute medicine lasted between 1 minute and approximately 7 minutes. Only between 1.5% and 5% of handover communication content related to the communication of social issues. Interview participants described a range of tensions inherent in handover that require dynamic trade-offs. These are related to documentation, the verbal communication, the transfer of responsibility and the different goals and motivations that a handover may serve. Participants also described the management of flow of patients and of information across organisational boundaries as one of the most important factors influencing the quality of handover. This includes management of patient flows in and out of departments, the influence of time-related performance targets, and the collaboration between organisations and departments. The two themes are related. The management of patient flow influences the way trade-offs around inner tensions are made, and, on the other hand, one of the goals of handover is ensuring adequate management of patient flows. Conclusions The research findings suggest that handover should be understood as a sociotechnical activity embedded in clinical and organisational practice. Capacity, patient flow and national targets, and the quality of handover are intricately related, and should be addressed together. Improvement efforts should focus on providing practitioners with flexibility to make trade-offs in order to resolve tensions inherent in handover. Collaborative holistic system analysis and greater cultural awareness and collaboration across organisations should be pursued. Funding The National Institute for Health Research Health Services and Delivery Research programme.

Joint Interference Coordination and Load Balancing for OFDMA Multihop Cellular Networks

Abstract: Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. However, there are still three issues not well addressed. With the existence of relay stations (RSs), how to efficiently allocate frequency resource to relay links becomes a challenging design issue. For mobile stations (MSs) near the cell edge, cochannel interference (CCI) become severe, which significantly affects the network performance. Furthermore, the unbalanced user distribution will result in traffic congestion and inability to guarantee quality of service (QoS). To address these problems, we propose a quantitative study on adaptive resource allocation schemes by jointly considering interference coordination (IC) and load balancing (LB) in MCNs. In this paper, we focus on the downlink of OFDMA-based MCNs with time division duplex (TDD) mode, and analyze the characteristics of resource allocation according to IEEE 802.16j/m specification. We also design a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and provide practical LB-based handover mechanisms which can evenly distribute the traffic and guarantee users' QoS. Our study shows that our scheme not only meets the requirement on coverage, but also improves the throughput while accommodating more users in MCNs.

Method and apparatus for handover in communication system

Abstract: A method for a serving base station to determine a handover time in a communication system is provided. The method includes determining whether to set up dual connectivity (DC) with respect to a terminal with a target base station that transmits the beacon if it is recognized that the terminal receives a beacon including a plurality of pieces of service coverage area information, and determining whether to execute a handover to the target base station based on a measurement report of the terminal, which is received after the DC is set up if the DC is set up.

TCP Performance over Mobile Networks in High-Speed Mobility Scenarios

Abstract: Recently, the performance of mobile data networks has been evaluated from many aspects, e.g., TCP/IP protocols, comparison with WiFi or even satellite communication, under different movements within a metropolis area. Nevertheless, the result is still unknown in high-speed mobility scenarios and in a scale that crosses different metropolis and geographic areas. To fill in this blank, we carry out a comprehensive measurement study on the performance of mobile data networks under high-speed mobility, i.e., 300 km/h or above. Such speed is the current de facto standard of the China Railway High speed (CRH) network, the largest commercial high-speed railway network in the world so far. We first present an overview on the TCP performance over LTE networks. We observe that decent throughput may exist under high-speed mobility. However, comparing to the stationary and driving (100 km/h) scenarios, the throughput and RTT not only are worse, but also have a large variance. We then take an in-depth investigation into two key factors affecting the performance, i.e., The wireless channel and handoff. We believe our study on these factors is useful not only for TCP, but also for other upper-layer protocols.

Wireless sensor networks mobility management using fuzzy logic

Abstract: This paper presents a novel, intelligent controller to support mobility in wireless sensor networks In particular, the focus is on the deployment of such mobility solution to critical applications, like personnel safety in an industrial environment A Fuzzy Logic-based mobility controller is proposed to aid sensor Mobile Nodes (MN) to decide whether they have to trigger the handoff procedure and perform the handoff to a new connection position or not To do so, we use a combination of two locally available metrics, the RSSI and the Link Loss, in order to ''predict'' the End-to-End losses and support the handoff triggering procedure As a performance evaluation environment, a real industrial setting (oil refinery) is used Based on on-site experiments run in the oil refinery testbed area, the proposed mobility controller has shown significant benefits compared to other conventional solutions, in terms of packet loss, packet delivery delay, energy consumption, and ratio of successful handoff triggers

Path selection using handover in mobile networks with cloud-enabled small cells

Abstract: To overcome latency constrain of common mobile cloud computing, computing capabilities can be integrated into a base station in mobile networks This exploitation of convergence of mobile networks and cloud computing enables to take advantage of proximity between a user equipment (UE) and its serving station to lower latency and to avoid backhaul overloading due to cloud computing services This concept of cloud-enabled small cells is known as small cell cloud (SCC) In this paper, we propose algorithm for selection of path between the UE and the cell, which performs computing for this particular UE As a path selection metrics we consider transmission delay and energy consumed for transmission of offloaded data The path selection considering both metrics is formulated as Markov Decision Process Comparing to a conventional delivery of data to the computing small cells, the proposed algorithm enables to reduce the delay by 9% and to increase users' satisfaction with experienced delay by 65%

An Effective Handover Scheme Based on Antenna Selection in Ground–Train Distributed Antenna Systems

Abstract: Due to frequent handovers in broadband wireless communications for the high-speed railway system, communication interruption caused by handover failures could seriously degrade the users' experience. Aiming at reducing the handover failure probability, this paper proposes an effective handover scheme based on the distributed antenna system (DAS) and mobile-relay-aided two-link architecture, i.e., ground-relay link and relay-onboard link, where the mobile relay is mounted on top of the moving train. In addition, an antenna selection scheme with optimal power allocation is proposed to improve handover performance. Our simulation and analysis results show that the DAS structure with macrodiversity can reduce the unnecessary handovers, as well as reduce the handover failure and link outage probabilities compared with the traditional cell without DAS. In addition, the proposed DAS with an antenna selection scheme performs better in terms of handover failure and link outage probabilities than that of DAS with a equal power allocation (EPA) scheme.