Search results for "FAD"
showing 10 items of 292 documents
Classes of sum-of-cisoids processes and their statistics for the modeling and simulation of mobile fading channels
2013
Published version of an article in the journal: EURASIP Journal on Wireless Communications and Networking. Also available from the publisher at: http://dx.doi.org/10.1186/1687-1499-2013-125 Open access In this paper, we present a fundamental study on the stationarity and ergodicity of eight classes of sum-of-cisoids (SOC) processes for the modeling and simulation of frequency-nonselective mobile Rayleigh fading channels. The purpose of this study is to determine which classes of SOC models enable the design of channel simulators that accurately reproduce the channel’s statistical properties without demanding information on the time origin or the time-consuming computation of an ensemble ave…
An Ergodic Sum-of-Cisoids Simulator for Multiple Uncorrelated Rayleigh Fading Channels Under Generalized Scattering Conditions
2012
In this paper, we present a new method for the design of ergodic sum-of-sinusoids (SOS) simulators for multiple uncorrelated narrowband Rayleigh fading channels. The method, which is intended for a special class of SOS models known as sum-of-cisoids (SOC) models, enables the generation of an unlimited number of mutually uncorrelated Rayleigh fading waveforms with specified autocorrelation properties. This is in contrast to all known methods proposed for SOS simulators, which are restricted to the simulation of multiple uncorrelated Rayleigh fading channels characterized by autocorrelation functions (ACFs) derived under the isotropic scattering assumption. The excellent performance of this n…
On the first- and second-order statistics of the capacity of N*Nakagami-m channels for applications in cooperative networks
2012
This article deals with the derivation and analysis of the statistical properties of the instantaneous channel capacitya of N*Nakagami-m channels, which has been recently introduced as a suitable stochastic model for multihop fading channels. We have derived exact analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the instantaneous channel capacity of N*Nakagami-m channels. For large number of hops, we have studied the first-order statistics of the instantaneous channel capacity by assuming that the fading amplitude of the channel can approximately be modeled as a lognor…
The generalized method of equal areas for the design of sum-of-cisoids simulators for mobile Rayleigh fading channels with arbitrary Doppler spectra
2011
We present in this paper a generalized version of the method of equal areas (MEA) that is well suited for the design of sum-of-cisoids (SOC) simulators for narrowband mobile Rayleigh fading channels characterized by any type of Doppler power spectral densities (DPSDs). Unlike the original MEA, the generalized MEA (GMEA) can be applied to the simulation of fading channels with asymmetrical DPSDs. This is an important feature because the simulation of such channels is of great interest for the laboratory analysis of mobile communication systems under non-isotropic scattering conditions. We show that irrespective of the underlying DPSD, the GMEA results in a very good approximation to the auto…
Towards Efficient Control of Mobile Network-Enabled UAVs
2019
| openaire: EC/H2020/815191/EU//PriMO-5G The efficient control of mobile network-enabled unmanned aerial vehicles (UAVs) is targeted in this paper. In particular, a downlink scenario is considered, in which control messages are sent to UAVs via cellular base stations (BSs). Unlike terrestrial user equipment (UEs), UAVs perceive a large number of BSs, which can lead to increased interference causing poor or even unacceptable throughput. This paper proposes a framework for efficient control of UAVs. First, a communication model is introduced for flying UAVs taking into account interference, path loss and fast fading. The characteristics of UAVs make such model different compared to traditiona…
Modelling and Analysis of Non-Stationary Multipath Fading Channels with Time-Variant Angles of Arrival
2017
In mobile radio channel modelling, it is generally assumed that the angles of arrival (AOAs) are independent of time. This assumption does in general not agree with real-world channels in which the AOAs vary with the position of a moving receiver. In this paper, we first present a mathematical model for the time-variant AOAs. This model serves as the basis for the development of two non-stationary multipath fading channels models. The statistical properties of both channel models are analysed with emphasis on the time-dependent autocorrelation function (ACF), time-dependent mean Doppler shift, time-dependent Doppler spread, and the Wigner-Ville spectrum. It is shown that these characteristi…
Performance of Hybrid-ARQ with Incremental Redundancy over Double Rayleigh Fading Channels
2011
In this paper, we study the performance of hybrid automatic repeat request (HARQ) with incremental redundancy (IR) over double Rayleigh channels. Such channels can be used to model the fading amplitude for vehicle-to-vehicle (V2V) communications. We study the performance of HARQ from an information theoretic perspective. Analytical expressions are derived for the $\epsilon$-outage capacity, the average number of transmissions, and the average transmission rate for HARQ with IR, assuming a maximum number of rounds for the HARQ protocol. In our study, the communication rate per HARQ round is adjusted to the average signal-to-noise ratio (SNR) such that a target outage probability is not excee…
Enhancing HSUPA system level performance with dual carrier capability
2010
The purpose of this paper is to analyze how dual carrier capability can enhance High Speed Uplink Packet Access performance in comparison to using only single carrier. Dual carrier operation gives the User Equipment the possibility to transmit simultaneously using two 5 MHz bands, theoretically doubling the peak data rates and user throughput. The analysis is conducted with a system level simulation tool. This paper first indicates with single carrier simulations that, especially in small cells, terminals have spare power available for dual carrier operation. These observations are verified with dual carrier simulations by showing that the burst throughput can be practically doubled. In the…
Outage Probability Analysis of User-Centric SBS-Based HCNets Under Hybrid Rician/Rayleigh Fading
2020
To model dense user equipment (UE) distribution in heterogeneous cellular networks (HCNets), the Poisson cluster process (PCP) has emerged as a promising tool. In user-centric HCNets where UEs are distributed according to a PCP around a small base station (SBS), the network performance has been commonly studied in literature under a Rayleigh fading environment assumption. However, such an assumption may not hold in user-centric HCNets given the possible existence of a strong line-of-sight (LOS) link between UEs and BSs due to a relatively short transmission distance. This letter analyzes the performance of user-centric SBS based HCNets by considering that the desired LOS link experiences Ri…
Fake Nodes approximation for Magnetic Particle Imaging
2020
Accurately reconstructing functions with discontinuities is the key tool in many bio-imaging applications as, for instance, in Magnetic Particle Imaging (MPI). In this paper, we apply a method for scattered data interpolation, named mapped bases or Fake Nodes approach, which incorporates discontinuities via a suitable mapping function. This technique naturally mitigates the Gibbs phenomenon, as numerical evidence for reconstructing MPI images confirms.