Search results for "0508 media and communications"
showing 10 items of 683 documents
Constraint Hubs Deployment for efficient Machine-Type-Communications
2018
Massive Internet of Things (mIoT) is an important use case of 5G. The main challenge for mIoT is the huge amount of uplink traffic as it dramatically overloads the radio access network (RAN). To mitigate this shortcoming, a new RAN technology has been suggested, where small cells are used for interconnecting different devices to the network. The use of small cells will alleviate congestion at the RAN, reduce the end-to-end (E2E) delay, and increase the link capacity for communications. In this paper, we devise three solutions for deploying and interconnecting small cells that would handle mIoT traffic. A realistic physical model is considered in these solutions. The physical model is based …
Wireless sensor network for Spectrum Cartography based on Kriging interpolation
2012
Dynamic spectrum access with Cognitive Radio (CR) network is a promising approach to increase the efficiency of spectrum usage. To allow the optimization of resource allocation and transmission adaptation techniques, each CR terminal needs to acquire awareness of the state of the time-frequency-location varying radio spectrum. In this paper we present a Spectrum Cartography (SC) approach where CR terminals are supported by a fixed wireless sensor network (WSN) to estimate and update the Power Spectral Density (PSD) over the area of interest. The wireless sensors collaborate to estimate the spatial distribution of the received power at a given frequency using either a centralized or a distri…
MDP-based Resource Allocation for Uplink Grant-free Transmissions in 5G New Radio
2020
The diversity of application scenarios in 5G mobile communication networks calls for innovative initial access schemes beyond traditional grant-based approaches. As a novel concept for facilitating small packet transmission and achieving ultra-low latency, grant-free communication is attracting lots of interests in the research community and standardization bodies. However, when a network consists of both grant based and grant-free based end devices, how to allocate slot resources properly between these two categories of devices remains as an unanswered question. In this paper, we propose a Markov decision process based scheme which dynamically allocates grant-free resources based on a spec…
Hidden Markov Model Based Machine Learning for mMTC Device Cell Association in 5G Networks
2019
Massive machine-type communication (mMTC) is expected to play a pivotal role in emerging 5G networks. Considering the dense deployment of small cells and the existence of heterogeneous cells, an MTC device can discover multiple cells for association. Under traditional cell association mechanisms, MTC devices are typically associated with an eNodeB with highest signal strength. However, the selected eNodeB may not be able to handle mMTC requests due to network congestion and overload. Therefore, reliable cell association would provide a smarter solution to facilitate mMTC connections. To enable such a solution, a hidden Markov model (HMM) based machine learning (ML) technique is proposed in …
Analysis of interference avoidance with load balancing in heterogeneous cellular networks
2016
In heterogeneous cellular networks (HCNets) smallcells are overlaid with macro-cells to handle heavy cellular data traffic in an efficient way. To achieve fast and reliable access to data with a better coverage it is necessary to offload users to the underutilized small-cells from the congested macro-cells. Sharing of the same licensed frequency spectrum by smallcells and macro-cells results in heavy cross-tier interference which significantly affects the downlink SINR. In this paper, we investigate and analyze a joint frequency-division duplex based cross-tier complementary spectrum sharing technique which is also regarded as reverse frequency allocation (RFA) scheme with load balancing. T…
Reliable Underlay Device-to-Device Communications on Multiple Channels
2019
Device-to-device (D2D) communications provide a substantial increase in spectrum usage and efficiency by allowing nearby users to communicate directly without passing their packets through the base station (BS). In previous works, proper channel assignment and power allocation algorithms for sharing of channels between cellular users and D2D pairs, usually require exact knowledge of the channel-state-information (CSI). However, due to the non-stationary wireless environment and the need to limit the communication and computation overheads, obtaining perfect CSI in the D2D communication scenario is generally not possible. In this work, we propose a joint channel assignment and power allocati…
Cooperative or non-cooperative transmission in synchronous DC WSNs: A DTMC-based approach
2017
Cooperative transmission (CT) enables balanced energy consumption among sensor nodes and mitigates the energy hole problem in wireless sensor networks (WSNs). In typical CT enabled medium access control (MAC) protocols, a source node decides to trigger CT or not based on a residual energy comparison between itself and its relay node. In this paper, we propose a receiver initiated CT MAC protocol, in which the receiving node makes the decision on initiating CT or not based on a tradeoff between performing CT and non-CT. In this way, nodes can avoid idle listening and achieve an extended lifetime. A discrete-time Markov chain (DTMC) model is developed to analyze the performance of CT associat…
The Multimodality of Digital Longform Journalism
2016
Digital longform journalism has recently attracted increased attention among both academics and professionals. This study contributes to the growing body of research by dissecting the multimodal structure of digital longform journalism, that is, how the emerging genre combines written language, photography, short videos, maps and other graphical elements, and joins them together into a seamless narrative using subtle transitions. The data consist of 12 longform articles published in 2012–2013, which have been annotated for their visual and verbal content, their underlying principle of organization and the transitions that hold between them. The annotation is stored into a digital corpus, wh…
Symmetry of root and root canal morphology of mandibular incisors: A cone-beam computed tomography study
2019
Background Aim of this study was to analyze the root canal configuration in mandibular central and lateral incisors in vivo using cone-beam computed tomography (CBCT) imaging. Material and methods A total of 487 mandibular central incisors and 491 mandibular lateral incisors from 250 patients were examined using CBCT imaging, previously taken for diagnosis and treatment. The number of roots, root canal system configuration, presence of apical confluences, distance between confluences and radiographic root end, symmetry between left and right elements were recorded and statistically analyzed. Results All the examined teeth presented only one root. No significant differences were found betwee…
An OLPC Workshop in Rural Tanzania: Preliminary Results
2013
One-to-one computing is an active and widely researched topic in educational technology. Its benefits include, for instance, easily up datable material base, anywhere-anytime learning, adaptability, and simulated experiments in science. The use of one-to-one computing in a developing country context has recently become an active research topic. However, the materialization of the educational benefits requires proper contextualization regarding the necessary pedagogical, organizational, institutional, and other types of adaptation. This paper presents preliminary results from an action research study in a primary school in rural Tanzania. In that study, the utilization of one-to-one computin…