Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
Among the many kinds of networking technologies, the wireless ad hoc network is an important one for creating\nhigh-performance ubiquitous computing systems. The availability of a wireless ad hoc network (WANET) depends\nhighly upon the level of node reliability. System-level fault diagnosis has long been a subject for the purpose of\nmaintaining system reliability. This paper addresses the comparison-based approach to fault detection, and\naccordingly, we developed a localized algorithm for detecting faulty nodes in strongly one-step t-diagnosable\nWANETs. The contributions of this paper are highlighted as follows: (i) A localized fault detection algorithm is proposed\nfor strongly one-step t-diagnosable WANETs under the comparison model, (ii) the proposed algorithm is formally\nproved, and it incurs only linear time complexity, which is relatively efficient compared to some others in literature,\nand (iii) some examples are presented for clarifying how to accomplish the comparison-based fault detection process....
Earlier works have studied the energy efficiency (EE) of half-duplex Device-to-Device (D2D) communications. However, the EE\nof full-duplex D2D communications underlaying cellular networks which undergoes residual self-interference (SI) has not been\ninvestigated. In this paper, we focus on the EE of full-duplex D2D communications with uplink channel reuse and compare it with\nthe half-duplex counterpart, aiming to show which mode is more energy-efficient. Our goal is to find the optimal transmission\npowers to maximize the system EE while guaranteeing required signal-to-interference-plus-noise ratios (SINRs) and transmission\npower constraints.Theoptimal power allocation problem is modeled as a noncooperative game, inwhich each user equipment (UE)\nis self-interested and wants to maximize its own EE. An optimal iterative bisection-alternate optimization method is proposed to\nsolve the optimization problem from the noncooperative game-theoretic perspective. Simulation results show that the proposed\nmethod can achieve EE close to that obtained by an existingmethod but with lower complexity in half-duplex D2D communications\nunderlaying cellular networks.Moreover, the full-duplex D2D communications underlaying cellular networks outperformthe halfduplex\nD2D communications underlaying cellular networks in terms of EE when effective SI mitigation techniques are applied....
A new paradigm of wireless video delivery between users in the converged D2D network and cellular system is studied in this paper.\nD2D communication enables direct data transmissions of nearby user equipment (UE) by sharing the same time and frequency\nresource, thereby improving spectrum utilization, system throughput, and energy efficiency. Yet in the case that D2D network\ncannot provide the requested video files for the limited storage capacity of UE, users have to access the video files in the traditional\ncellular mode. This paper investigates a D2D-cellular converged network where users are scattered over the area of a single cell\naccording to the spatial Poisson Point Processes and D2D users are able to store part of video files requested by other users according\nto file popularity. First, we derive the energy efficiency of the D2D-cellular converged network. Then, to maximize the energy\nefficiency of the D2D-cellular converged network, the optimal collaborative distance of D2D communication and the number of\ncache files are addressed. Finally, via simulations, we show the effects of these system parameters on energy efficiency and point out\nthe existence of optimal solutions....
We introduce the concept of self-organizing VCN (virtual cell network). Here self-organizing VCN topology for efficient operation\nwill be configured, and the functions of the each element will be defined. Also, the operation scenarios of VCN will be described.\nThen, we propose an efficient scheduling algorithm that considers the asymmetry of interference between downlink and uplink to\nmitigate intercell interference with little computing overhead. The basic concept is to construct scheduling groups that consist of\nseveral users. Each user in a scheduling group is affiliated with a different cell. Then, the intercell groups are managed efficiently in\nthe proposed VCNs.There is no need for the exchange of a lot of information among base stations to schedule the users over the\nentire network....
In this paper, we present a framework for estimating trajectories of cellular networks users based on mobile network\noperator data. We use handover and location area update events of both speech and packet data users captured in\nthe core network of the Austrian MNO A1 to estimate the subscribers� mobility behavior. By utilizing publicly available\ndata, i.e., environmental information, road infrastructure data, transmitter power ranges and antenna characteristics,\nour approach allows the estimation of subscriber trajectories for both urban and semi-rural environments with a good\naccordance to the actual trajectories. Additionally, we present a method to estimate a particular subscriber�s\nmovement velocity, on the basis of mentioned data. Furthermore, we propose a methodology to estimate when a\nparticular user started or ended a speech or packet data session during his journey, based on mobility-related network\nevents. With this, our framework enables the creation of reproducible mobility situations for cellular network\nsimulations at system level....
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