21,097 research outputs found
Off-body wireless link simulation framework using deterministic channel modeling
Body-centric communication concerns wireless links in which the human body represents the central element, exchanging data by means of wearable antennas with a different node in the external environment or on the human body itself. During the link design phase, it is very advantageous to be able to model the link and predict its performance before its real implementation, resulting in reduction of design time and costs. In the present contribution, we propose a novel computer simulation framework to describe a complete off-body communication link between a human user and a remote base station, including all the components of the communication link such as wearable and fixed antennas, human body and propagation channel at the physical level, also taking into account the digital data transmission at link level. The proposed framework was constructed by applying the most appropriate modeling tools for each component, including ray tracing for the deterministic channel modeling. The framework provides as output the most common link performance parameters such as Bit-Error-Rate (BER), received Signal-to-Noise Ratio (SNR) and channel correlations. The validity of the proposed method was verified by comparing the figures of merit of a real off-body communication link, studied during a previous measurement campaign, with the ones obtained by the proposed simulation framework. A good agreement is obtained in terms of both BERs and SNRs
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Indoor wireless communications and applications
Chapter 3 addresses challenges in radio link and system design in indoor scenarios. Given the fact that most human activities take place in indoor environments, the need for supporting ubiquitous indoor data connectivity and location/tracking service becomes even more important than in the previous decades. Specific technical challenges addressed in this section are(i), modelling complex indoor radio channels for effective antenna deployment, (ii), potential of millimeter-wave (mm-wave) radios for supporting higher data rates, and (iii), feasible indoor localisation and tracking techniques, which are summarised in three dedicated sections of this chapter
End-to-End Simulation of 5G mmWave Networks
Due to its potential for multi-gigabit and low latency wireless links,
millimeter wave (mmWave) technology is expected to play a central role in 5th
generation cellular systems. While there has been considerable progress in
understanding the mmWave physical layer, innovations will be required at all
layers of the protocol stack, in both the access and the core network.
Discrete-event network simulation is essential for end-to-end, cross-layer
research and development. This paper provides a tutorial on a recently
developed full-stack mmWave module integrated into the widely used open-source
ns--3 simulator. The module includes a number of detailed statistical channel
models as well as the ability to incorporate real measurements or ray-tracing
data. The Physical (PHY) and Medium Access Control (MAC) layers are modular and
highly customizable, making it easy to integrate algorithms or compare
Orthogonal Frequency Division Multiplexing (OFDM) numerologies, for example.
The module is interfaced with the core network of the ns--3 Long Term Evolution
(LTE) module for full-stack simulations of end-to-end connectivity, and
advanced architectural features, such as dual-connectivity, are also available.
To facilitate the understanding of the module, and verify its correct
functioning, we provide several examples that show the performance of the
custom mmWave stack as well as custom congestion control algorithms designed
specifically for efficient utilization of the mmWave channel.Comment: 25 pages, 16 figures, submitted to IEEE Communications Surveys and
Tutorials (revised Jan. 2018
The COST IRACON Geometry-based Stochastic Channel Model for Vehicle-to-Vehicle Communication in Intersections
Vehicle-to-vehicle (V2V) wireless communications can improve traffic safety
at road intersections and enable congestion avoidance. However, detailed
knowledge about the wireless propagation channel is needed for the development
and realistic assessment of V2V communication systems. We present a novel
geometry-based stochastic MIMO channel model with support for frequencies in
the band of 5.2-6.2 GHz. The model is based on extensive high-resolution
measurements at different road intersections in the city of Berlin, Germany. We
extend existing models, by including the effects of various obstructions,
higher order interactions, and by introducing an angular gain function for the
scatterers. Scatterer locations have been identified and mapped to measured
multi-path trajectories using a measurement-based ray tracing method and a
subsequent RANSAC algorithm. The developed model is parameterized, and using
the measured propagation paths that have been mapped to scatterer locations,
model parameters are estimated. The time variant power fading of individual
multi-path components is found to be best modeled by a Gamma process with an
exponential autocorrelation. The path coherence distance is estimated to be in
the range of 0-2 m. The model is also validated against measurement data,
showing that the developed model accurately captures the behavior of the
measured channel gain, Doppler spread, and delay spread. This is also the case
for intersections that have not been used when estimating model parameters.Comment: Submitted to IEEE Transactions on Vehicular Technolog
Analysis of Energy Consumption Performance towards Optimal Radioplanning of Wireless Sensor Networks in Heterogeneous Indoor Environments
In this paper the impact of complex indoor environment in the deployment and energy consumption of a wireless sensor network infrastructure is analyzed. The variable nature of the radio channel is analyzed by means of deterministic in-house 3D ray launching simulation of an indoor scenario, in which wireless sensors, based on an in-house CyFi implementation, typically used for environmental monitoring, are located. Received signal power and current consumption measurement results of the in-house designed wireless motes have been obtained, stating that adequate consideration of the network topology and morphology lead to optimal performance and power consumption reduction. The use of radioplanning techniques therefore aid in the deployment of more energy efficient elements, optimizing the overall performance of the variety of deployed wireless systems within the indoor scenario
UWB Indoor Radio Propagation Modelling in Presence of Human Body Shadowing Using Ray Tracing Technique
This paper presents a ray-tracing method for modelingUltra Wide Bandwidth indoor propagation channels. Avalidation of the ray tracing model with our indoor measurementis also presented. Based on the validated model, the multipathchannel parameter like the fading statistics and root mean squarerms delay spread for Ultra Wide bandwidth frequencies aresimply extracted. The proposed ray-tracing method is basedon image method. This is used to predict the propagation ofUWB electromagnetic waves. First, we have obtained that thefading statistics can be well fitted by log normal distributionin static case. Second, as in realistic environment we cannotneglect the significant impact of Human Body Shadowing andother objects in motion on indoor UWB propagation channel.Hence, our proposed model allows a simulation of propagationin a dynamic indoor environment. Results of the simulation showthat this tool gives results in agreement with those reported inthe literature. Specially, the effects of people motion on temporalchannel properties. Other features of this approach also areoutlined
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