Abstract: The rapidly increasing number of mobile devices, voluminous data, and higher data rate are pushing to rethink the current generation of the cellular mobile communication The next or fifth generation (5G) cellular networks are expected to meet high-end requirements The 5G networks are broadly characterized by three unique features: ubiquitous connectivity, extremely low latency, and very high-speed data transfer The 5G networks would provide novel architectures and technologies beyond state-of-the-art architectures and technologies In this paper, our intent is to find an answer to the question: "what will be done by 5G and how?" We investigate and discuss serious limitations of the fourth generation (4G) cellular networks and corresponding new features of 5G networks We identify challenges in 5G networks, new technologies for 5G networks, and present a comparative study of the proposed architectures that can be categorized on the basis of energy-efficiency, network hierarchy, and network types Interestingly, the implementation issues, eg, interference, QoS, handoff, security-privacy, channel access, and load balancing, hugely effect the realization of 5G networks Furthermore, our illustrations highlight the feasibility of these models through an evaluation of existing real-experiments and testbeds

Abstract: Satellite networks have traditionally been considered for specific purposes. Recently, new satellite technologies have been pushed to the market enabling high-performance satellite access networks. On the other hand, network architectures are taking advantage of emerging technologies such as software-defined networking (SDN), network virtualization and network functions virtualization (NFV). Therefore, benefiting communications services over satellite networks from these new technologies at first, and their seamless integration with terrestrial networks at second, are of great interest and importance. In this paper, and through comprehensive use cases, the advantages of introducing network programmability and virtualization using SDN and/or NFV in satellite networks are investigated. The requirements to be fulfilled in each use case are also discussed.

Abstract: Self-driving vehicles are able to drive on their own as long as the requirements of their autonomous systems are met. If the system reaches the boundary of its capabilities, the system has to de-escalate (e.g. emergency braking) or hand over control to the human driver. Accordingly, the design of a functional handover assistant requires that it enable drivers to both take over control and feel comfortable while doing so -- even when they were "out of the loop" with other tasks. We introduce a process to hand over control from a full self-driving system to manual driving, and propose a number of handover implementation strategies. Moreover, we designed and implemented a handover assistant based on users' preferences and conducted a user study with 30 participants, whose distraction was ensured by a realistic distractor task. Our evaluation shows that car-driver handovers prompted by multimodal (auditory and visual) warnings are a promising strategy to compensate for system boundaries of autonomous vehicles. The insights we gained from the take-over behavior of drivers led us to formulate recommendations for more realistic evaluation settings and the design of future handover assistants.

Abstract: Heterogeneous small cell networks have attracted much attention for satisfying users’ explosive data traffic requirements. The heterogeneous cloud small cell network (HCSNet), which combines cloud computing and a heterogeneous small cell network, will likely play an important role in 5G mobile communication networks. However, with massive deployment of small cells, co-channel interference and handover management are two important problems in an HCSNet, especially for cell edge users. In this article, we examine the problems of cooperative interference mitigation and handover management in an HCSNet. A network architecture is described to combine cloud radio access network with small cells. An effective CoMP clustering scheme using affinity propagation is adopted to mitigate cell edge users’ interference. A low-complexity handover management scheme is presented, and its signaling procedure is analyzed in an HCSNet. Numerical results show that with the proposed network architecture, CoMP clustering and handover management schemes can significantly increase the capacity of HCSNet while maintaining users’ quality of service.

Abstract: In this paper, a hybrid network combining light fidelity (Li-Fi) with a radio frequency (RF) wireless fidelity (Wi-Fi) network is considered An additional tier of very small Li-Fi attocells which utilize the visible light spectrum, offers a significant increase in the wireless data throughput in an indoor environment, while at the same time providing room illumination Importantly, there is no interference between Li-Fi and Wi-Fi A Li-Fi attocell covers a significantly smaller area than a Wi-Fi access point (AP) This means that even with a moderate user movement a large number of handover between Li-Fi attocells can occur, and this compromises the system throughput Dynamic load balancing (LB) can mitigate this issue so that the quasi-static users are served by Li-Fi attocells, while moving users are served by a Wi-Fi AP However, due to the user movement, local overload situations may occur which prevent handover, leading to a lower throughput This research studies LB in a hybrid Li-Fi/Wi-Fi network by taking into account user mobility and handover signalling overheads Furthermore, a dynamic LB scheme is proposed, where the utility function considers system throughput and fairness In order to better understand the handover effect on the LB, the service areas of different APs are studied, and the throughput of each AP by employing the proposed LB scheme is analyzed

Abstract: Heterogeneous small cell network has attracted much attention to satisfy users' explosive data traffic requirements. Heterogeneous cloud small cell network (HCSNet), which combines cloud computing and heterogeneous small cell network, will likely play an important role in 5G mobile communication networks. However, with massive deployment of small cells, co-channel interference and handover management are two important problems in HCSNet, especially for cell edge users. In this article, we examine the problems of cooperative interference mitigation and handover management in HCSNet. A network architecture is described to combine cloud radio access network with small cells. An effective coordinated multi-point (CoMP) clustering scheme using affinity propagation is adopted to mitigate cell edge users' interference. A low complexity handover management scheme is presented, and its signaling procedure is analyzed in HCSNet. Numerical results show that the proposed network architecture, CoMP clustering scheme and handover management scheme can significantly increase the capacity of HCSNet while maintaining users' quality of service.

Abstract: The present disclosure relates to a pre-5 th -generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4 th -generation (4G) communication system such as long term evolution (LTE). A communication method and apparatus using beamforming are provided. The method includes acquiring transmission beam specific, measurement information of a base station (BS) and measuring a reference signal (RS) transmitted through transmission beams of the BS according to the transmission beam specific, measurement information. The measurement information on each transmission beam is determined according to at least one of an elevation angle of the corresponding transmission beam, an azimuth of the corresponding transmission beam, a handover urgency, information on a handover failure, and information on a radio link failure (RLF). A mobile station (MS) may perform a measurement report or a handover process according to a result of the measurement.

Abstract: SUMMARY Triggered by the explosion of mobile traffic, 5G (5th Generation) cellular network requires evolution to increase the system rate 1000 times higher than the current systems in 10 years. Motivated by this common problem, there are several studies to integrate mm-wave access into current cellular networks as multi-band heterogeneous networks to exploit the ultra-wideband aspect of the mm-wave band. The authors of this paper have proposed comprehensive architecture of cellular networks with mmwave access, where mm-wave small cell basestations and a conventional macro basestation are connected to Centralized-RAN (C-RAN) to effectively operate the system by enabling power efficient seamless handover as well as centralized resource control including dynamic cell structuring to match the limited coverage of mm-wave access with high traffic user locations via user-plane/control-plane splitting. In this paper, to prove the effectiveness of the proposed 5G cellular networks with mm-wave access, system level simulation is conducted by introducing an expected future traffic model, a measurement based mm-wave propagation model, and a centralized cell association algorithm by exploiting the C-RAN architecture. The numerical results show the effectiveness of the proposed network to realize 1000 times higher system rate than the current network in 10 years which is not achieved by the small cells using commonly considered 3.5 GHz band. Furthermore, the paper also gives latest status of mm-wave devices and regulations to show the feasibility of using mm-wave in the 5G systems.

Abstract: Recently, the mobile relay technique has been discussed to support communication services for Long-Term Evolution Advanced (LTE-A) high-speed rail networks. In the network, there are several mobile relays in a train. User equipment (UE) devices connect to in-car mobile relays instead of outside evolved NodeBs (eNBs). Mobile relays establish backhaul links with the serving donor eNBs (DeNBs) and coordinate control and data flows for UE devices. Since the train travels in high speed, mobile relays suffer from frequent handovers between DeNBs. We observe that the defined handover procedures in LTE-A specifications may incur message overhead and lengthen handover time. In this paper, we propose an enhanced handover scheme, which contains two procedures. The first procedure is an enhanced measurement procedure, which can accelerate the measurement procedure when the mobile relay knows that the train is moving toward some neighbor DeNBs. The second procedure is a group in-network handover procedure, which can aggregate similar in network handover procedures in the core network. Performance evaluations indicate that our design can conserve both time and messages when handover.

Abstract: Many machine-to-machine (M2M) devices and portable user devices have the ability to switch between cellular technology and satellite technology to ensure network connectivity. While the automatic handover is useful, there are situations where it is desirable to have greater control over the configuration of the communication modes of these devices. Accordingly, embodiments of the present invention describe the ability to designate a prioritized list of communication modes, the ability to manually configure communication modes directly on the device, the ability to configure communication modes remotely over the air, and the ability to configure communication modes according to a geofence.

Abstract: Many machine-to-machine (M2M) devices and portable user devices have the ability to switch between cellular technology and satellite technology to ensure network connectivity. While the automatic handover is useful, there are situations where it is desirable to have greater control over the configuration of the communication modes of these devices. Accordingly, embodiments of the present invention describe the ability to designate a prioritized list of communication modes, the ability to manually configure communication modes directly on the device, the ability to configure communication modes remotely over the air, and the ability to configure communication modes according to a geofence.

Abstract: «I’ve seen many, many examples of things that go terribly wrong, because the communication of handover information has failed in some way».

Abstract: In research community, a new radio access network architecture with a logical separation between control plane (CP) and data plane (DP) has been proposed for future cellular systems. It aims to overcome limitations of the conventional architecture by providing high data rate services under the umbrella of a coverage layer in a dual connection mode. This configuration could provide significant savings in signalling overhead. In particular, mobility robustness with minimal handover (HO) signalling is considered as one of the most promising benefits of this architecture. However, the DP mobility remains an issue that needs to be investigated. We consider predictive DP HO management as a solution that could minimise the out-of-band signalling related to the HO procedure. Thus we propose a mobility prediction scheme based on Markov Chains. The developed model predicts the user's trajectory in terms of a HO sequence in order to minimise the interruption time and the associated signalling when the HO is triggered. Depending on the prediction accuracy, numerical results show that the predictive HO management strategy could significantly reduce the signalling cost as compared with the conventional non-predictive mechanism.

Abstract: In this article, we propose dual-hop network architecture capable of providing high-speed communications to high-speed trains (HSTs). The system uses a seamless fiber-millimeterwave system for backhaul transmission from a central station to antennas on trains, and a highspeed in-train Wi-Fi network. The system can be combined with signal processing and network control technologies to compensate for interference and the Doppler effect, and to reduce the number of handovers. It can realize seamless connectivity between the inside and outside of trains to avoid penetration loss and help organize the in-train network optimally to increase coverage and data rate. We present and discuss the possible network architecture and technologies that can help realize the proposed network. We also present a proof-of-concept demonstration on a high-performance seamless fiber- MMW system that can be applied for applications in backhaul networks. The proposed network can be an attractive solution to provide broadband services such as video on demand and high-speed mobile signals to users on HSTs.

Abstract: End users increasingly expect ubiquitous connectivity while on the move. With a variety of wireless access technologies available, we expect to always be connected to the technology that best matches our performance goals and price points. Meanwhile, sophisticated onboard units (OBUs) enable geolocation and complex computation in support of handover. In this paper, we present an overview of vertical handover techniques and propose an algorithm empowered by the IEEE 802.21 standard, which considers the particularities of the vehicular networks (VNs), the surrounding context, the application requirements, the user preferences, and the different available wireless networks [i.e., Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), and Universal Mobile Telecommunications System (UMTS)] to improve users' quality of experience (QoE). Our results demonstrate that our approach, under the considered scenario, is able to meet application requirements while ensuring user preferences are also met.

Abstract: A handover authentication module in mobile networks enables mobile nodes to securely and seamlessly roam over multiple access points. However, designing an appropriate handover authentication protocol is a difficult task because wireless networks are susceptible to attacks, and mobile nodes have limited power and processing capability. In this article, we identify the security and efficiency requirements of a good handover authentication protocol and analyze the existing related protocols, and show that many such protocols are either insecure or inefficient. Then we review a recently proposed protocol named PairHand, which has been shown to outperform all other protocols on security and efficiency. Furthermore, we propose a novel protocol named HashHand that not only inherits the merits of Pair- Hand and efficiently eliminates its security vulnerabilities, but also provides a session key update mechanism. Experiments using our implementation on resource-limited laptop PCs show that HashHand is feasible for practical mobile networks.

Abstract: For continuous services of mobile user equipment (UE), Long Term Evolution (LTE) systems conduct evolved node B (eNB) switching based on hard handover technology, which breaks a connection before the connection to the target eNB (T-eNB) is made. As handover service interruption seriously degrades network performance, precise knowledge of the handover (HO) performance is necessary in finding out defects of the current system and discovering clues for improvements. Although the performance of LTE handover and its anticipated effect on network services are important evaluation indexes, in existing literature only the theoretical performance is analyzed and very few actual measurements on practical LTE networks have been presented. In this article, the HO delay and handover interruption time (HIT) performance of LTE networks are measured for several cases in accordance with the average number of users in a cell. Based on the internal HO procedures that influence HO delay and HIT, the key parameters are analyzed. In addition, based on the estimated number of users in a cell, a reference probability density function (PDF) that can be used for HIT prediction is presented.

Abstract: Spectrum mobility in cognitive radio networks not only enables the secondary users to guarantee the desired QoS of the primary users but also grants an efficient exploitation of the available spectrum holes in the network. In this paper, we propose a probabilistic approach in determining the initial and target channels for the handoff procedure in a single secondary user network. To characterize the network, a queuing theoretical framework is introduced, and “stay” and “change” handoff policies are both addressed. The performance of the secondary user in terms of average sojourn and extended service times for secondary connections is analyzed, and convex optimization problems with the objective of minimizing those times as well as analytical solutions are presented. Simulation results confirm the validity of our analytical approach.

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, we propose a Fuzzy-Based Multi-Interface System (FBMIS), where each node is equipped with two interfaces: the traditional cellular network interface and Mobile Ad hoc Networks (MANET)interface. The proposed FBMIS system is able to switch from cellular to ad-hoc mode and vice versa. We consider four input parameters: Distance Between Nodes (DBN), Node Mobility (NM), Angle between Node and Base station (ANB), and User Request Security (URS). We evaluated the performance of the proposed system by computer simulations using MATLAB. The simulation results show that our system has a good performance.

Abstract: Handoff decision is key to service continuity when a user roams about. We propose a Kalman filtering and fuzzy logic approach to reducing handoff initiations, so as to support seamless communication. Kalman filtering is used as a channel equalization technique in channel propagation model, while a Mamdani fuzzy logic is applied subsequently for handoff decision. Several metrics such as received signal strength (RSS), data rate, velocity of mobile terminal, and traffic load are considered as criteria to initiate handoff from WLAN to the cellular network. Simulation results show that the proposed method reduces handoff initiations effectively.

Abstract: Techniques and systems are disclosed for addressing the challenges in interference and mobility management in broadband, UAV-assisted heterogeneous network (BAHN) scenarios. Implementations include BAHN control components, for example, at a controlling network node of a BAHN. Generally, a component implementing techniques for managing interference and handover in a BAHN gathers state data from network nodes or devices in the BAHN, determines a candidate BAHN model that optimizes interference and handover metrics, and determines and performs model adjustments to the network parameters, BS parameters, and UAV-assisted base station (UABS) device locations and velocities to conform to the optimized candidate BAHN model. Also described is a UABS apparatus having a UAV, communications interface for communicating with a HetNet in accordance with wireless air interface standards, and a computing device suitable for implementing BAHN control or reinforcement learning components.

Abstract: This letter presents a novel cell outage detection algorithm based on incoming handovers statistics. The main advantage of the proposed algorithm is that it uses neighbor measurements that allow to detect outage in two cases. First, when the cell in outage is able to report performance indicators; second, when these indicators are not available because the base station is affected. To evaluate the proposed algorithm and compare it with other approaches, a set of tests has been carried out using an LTE simulator and in a live LTE network.

Abstract: To enable robots to learn handover orientations from observing natural handovers, we conduct a user study to measure and compare natural handover orientations with giver-centered and receiver-centered handover orientations for twenty common objects. We use a distance minimization approach to compute mean handover orientations. We posit that, computed means of receiver-centered orientations could be used by robot givers to achieve more efficient and socially acceptable handovers. Furthermore, we introduce the notion of affordance axes for comparing handover orientations, and offer a definition for computing them. Observable patterns were found in receiver-centered handover orientations. Comparisons show that depending on the object, natural handover orientations may not be receiver-centered; thus, robots may need to distinguish between good and bad handover orientations when learning from natural handovers.

Abstract: Efficient hand-off algorithm enhances the capacity and quality of service (QoS) of cellular systems. Hand-off algorithm is used in wireless cellular systems to decide when and to which base station (BS) will receive the handoff call, without any service interruption. High altitude platforms (HAPs) is considered as a complementary BS to mobiles in an obstacle position. HAPs can supply services to uncovered areas of terrestrial systems, thus with the goodness of HAPs total capacity in a service-limited area will be improved. Recently, artificial neural network (ANN) has been utilized to improve hand-off algorithms due to its ability to handle large data. As a revolutionary wireless system, ANN helps in taking the hand-off decision based on receive signal strength, speed, traffic intensity, and directivity. Radial based function network is used for making a hand-off decision to the chosen neighbor BS. This paper presents novel approaches of combining HAPs and terrestrial system in a particular coverage area for the design of high performance hand-off algorithm. It is found that hand-off rate and blocking rate are greatly improved using ANN for handoff decision.

Abstract: Heterogeneous networks (HetNets) are expected to be a key feature of long-term evolution (LTE)-advanced networks and beyond and are essential for providing ubiquitous broadband user throughput. However, due to different coverage ranges of base stations (BSs) in HetNets, the handover performance of a user equipment (UE) may be significantly degraded, especially in scenarios where high-velocity UE traverse through small cells. In this article, we propose a context-aware mobility management (MM) procedure for small cell networks, which uses reinforcement learning techniques and inter-cell coordination for improving the handover and throughput performance of UE. In particular, the BSs jointly learn their long-term traffic loads and optimal cell range expansion and schedule their UE based on their velocities and historical data rates that are exchanged among the tiers. The proposed approach is shown not only to outperform the classical MM in terms of throughput but also to enable better fairness. Using the proposed learning-based MM approaches, the UE throughput is shown to improve by 80% on the average, while the handover failure probability is shown to reduce up to a factor of three.

Abstract: Systems and methods are disclosed for inter-system mobility in integrated LTE and trusted WLAN access networks (TWAN). An X2' interface, adapted for both control plane and user plane communications, exists between an eNB and WLAN access point. A WLAN that has a UE attached thereto that is communicating with an EPC communicates over the X2' interface with an (H)eNB to handover communications from the WLAN to the (H)eNB. Similarly, an (H)eNB that has a UE attached thereto communicates over the X2' interface with a WLAN to handover communications from the (H)eNB to the WLAN.

Abstract: The new frontier in cellular networks is harnessing the enormous spectrum available at millimeter wave (mmWave) frequencies above 28 GHz. The challenging radio propagation characteristics at these frequencies, and the use of highly directional beamforming, lead to intermittent links between the base station (BS) and the user equipment (UE). In this paper, we revisit the problem of cell selection to maintain an acceptable level of service, despite the underlying intermittent link connectivity typical of mmWave links. We propose a Markov Decision Process (MDP) framework to study the properties and performance of our proposed cell selection strategy, which jointly considers several factors such as dynamic channel load and link quality. We use the Value Iteration Algorithm (VIA) to solve the MDP, and obtain the optimal set of associations. We address the multi user problem through a distributed iterative approach, in which each UE characterizes the evolution of the system based on stationary channel distribution and cell selection statistics of other UEs. Through simulation results, we show that our proposed technique makes judicious handoff choices, thereby providing a significant improvement in the overall network capacity. Further, our technique reduces the total number of handoffs, thus lowering the signaling overhead, while providing a higher quality of service to the UEs.

Abstract: Dense Networks (DenseNet) and Multi-Radio Access Technologies (Multi-RATs) are considered as key features of the emerging fifth generation (5G) wireless systems. A Multi- RAT DenseNet is characterized by a very dense deployment of low- power base stations (BSs) and by a multi-tier architecture consisting of heterogeneous radio access technologies. In this work, we propose an effective RAT selection algorithm that efficiently manages the RAT handover procedure by (i) choosing the most suitable RAT that guarantees high system and user performance, and (ii) reducing unnecessary handover events. In particular, the decision to trigger a handover is based on a new system parameter named Reference Base Station Efficiency (RBSE). This parameter takes into account metrics related to both the system and the user: the BS transmitted power, the BS traffic load and the users' spectral efficiency. We compare, by simulation, the proposed scheme with the standardized 3GPP policies. Results show that the proposed RAT selection scheme significantly reduces the number of handovers and the end-to- end delay while maintaining high system throughput and user spectral efficiency.

Abstract: An apparatus that uses a method for processing handover by a terminal linked to a wireless network included in heterogeneous wireless networks and conducting a voice call service is provided. The method includes determining whether the terminal is required to perform handover of another wireless network included in the heterogeneous wireless networks, and upon determining that the handover is required, performing handover to the another wireless network, wherein the handover is determined by applying at least one handover condition to each of predetermined operation modes in the terminal conducting the voice call service.