12th TM – Louvain-la-Neuve, Belgium, January 27 – 29

TD # Title Author(s) Abstract WGs
TD(20)12001 IEEE 802.11ad SC-PHY Layer Simulator: Performance in Real-world 60GHz Indoor Channels Jiri Blumenstein, Jiri Milos, Ladislav Polak, Christoph Mecklenbräuker, Tomas Fryza Sufficiently wide radio frequency (RF) spectrum and wireless communication systems with high spectral flexibility are the key parts to deal with the enormous increase of the expected data throughputs. The IEEE 802.11ad technology, also known as WiGig, is operating in the license-free 60GHz bands with data rates up to 6.8Gbit/s. It is especially developed for indoor transmission scenarios. In this paper, we present a 60GHz indoor channel model for an IEEE 802.11ad single carrier physical layer (SC-PHY) MATLAB-based simulator. The channel model is based on real measurements realized in an indoor environment. Its implementation and utilization in our developed simulator is presented. Functionality of the proposed simulator as well as the usability of the millimeter wave indoor channel model are verified by simulations. The simulations show correlation between the RMS delay spread and the achievable data throughput. DWG2: PHY Layer
TD(20)12002 Trajectory-Joint Clustering Approach for Vehicle-to-Vehicle Channel Modeling Chen Huang, Andreas F. Molisch, Yangli-Ao Geng, Ruisi He, Bo Ai, Zhangdui Zhong Clustering of multipath components (MPCs) is an important aspect of propagation channel modeling. When a time series of measurements, based on movement of transmitter and/or receiver, is available, the temporal evolution of MPCs can be used as a basis for clustering. We present an algorithm that bases clustering not only on distance of MPCs in the delay/angle space, but also how similar the temporal evolution of their parameters are. Sample results obtained from a vehicle-to-vehicle measurement campaign show good performance of the proposed algorithm. DWG1: Radio Channels
TD(20)12003 A Power-Angle-Spectrum Based Clustering and Tracking Algorithm for Time-varying Radio Channels Chen Huang, Ruisi He, Zhangdui Zhong, Bo Ai, Yangli-Ao Geng, Zhimeng Zhong, Qingyong Li, Katsuyuki Haneda, Claude Oestges Radio channel modeling has been an important research topic, since the performance of any communication system depends on channel characteristics. So far, most existing clustering algorithms are conducted based on the multipath components (MPCs) extracted by using a high-resolution parameter estimation approach, e.g., SAGE or MUSIC, etc. However, most of the estimation approaches require prior information to extract MPCs. Moreover, the high-resolution estimation approaches usually result in relatively high complexity and thus the clusters can only be identified by using an off-line approach after the measurements. Therefore, a power angle spectrum based clustering and tracking algorithm (PASCT) is proposed in this paper. First, a power angle spectrum (PAS) is extracted from measurement data by using a Bartlett beamformer. For each PAS, the potential targets are selected from the background and separated into clusters by using image processing approaches. The recognized clusters are characterized by three attributes: i) size, ii) position, and iii) shape feature, where orientation histogram is developed to describe the shape feature of the clusters. Moreover, a cost minimizing tracking approach based on Kuhn-Munkres method is proposed to accurately identify the clusters in non-stationary channels. The proposed PASCT algorithm is validated based on both simulations and measurements. It is found that the dominating clusters in both line-of-sight and non-line-of-sight environments can be well recognized and tracked with the proposed algorithm. By using the proposed algorithm, the dynamic changes of the clusters in real-time channel measurements, e.g., number, birth-death process, and size of the clusters, can be well observed. Through the experiments, the proposed algorithm can achieve fairly good accuracy on the cluster identification with lower complexity compared to the conventional solution. DWG1: Radio Channels
TD(20)12004 Mobile propagation channel comparison at 3.7 GHz and 17.5 GHz in urban macro- and microcell environments Jean-Marc Conrat This paper presents a comparison between propagation channels at 3.7 GHz and 17.5 GHz. The study is based on measurement data extracted from a drive test-like measurement campaign performed in Belfort. Transfer functions defined with a 200 MHz bandwidth were collected in various urban environments. Metrics such as the path loss or the delay spread were calculated. The data analysis conducted through power profile visual inspection or channel metric statistical distribution indicates that the propagation channel structures at 3.7 GHz and 17.5 GHz are very similar. The average path loss differences between both frequencies calculated for different environment (dense urban, suburban, etc), for different BS antenna heights (macro, micro) and propagation conditions (LOS, NLOS, etc) are close to the theoretical value given by the free space reference and equal to 20*log10(freq). DWG1: Radio Channels
TD(20)12005 Towards a Non-Stationary Correlated Fading Process for Diffuse Scattering in Ray


Benjamin Rainer, David Lo ̈schenbrand, Stefan Zelenbaba, Markus Hofer, and Thomas Zemen In this paper we introduce the AIT ray tracer (RT) that is able to accurately simulate propagation effects of wireless communication channels. It covers the classical propagation mechanisms such as specular reflections, transmission and edge-diffraction. The novelty of our RT is that it allows to obtain correlated diffuse scattering and, thus,

provides a time-variant Doppler spectral density. This is achieved by introducing a lattice-based surface tiling, which does not alter the position of the scattering points during simulation but provides high resolution diffuse scattering. The selection of the basis vectors for the finite lattice ensures that each ray falls into a separate delay bin (at

least for first-order scattering). We implement our RT using the NVIDIA OptiX ray tracing engine, this enables us to trace a vast amount of rays in a single pass. We compare our RT simulations to a measurement conducted in a non-stationary urban intersection scenario achieving a near perfect match in terms of second order statistics.

DWG1: Radio Channels, DWG2: PHY Layer
TD(20)12006 Uncertainties Quantification for 5G-based localization by using Polynomial Chaos Expansion Alexey García Padilla, Sergio Lazaro Cabarrouy, François Horlin, Philippe De Doncker The fifth-generation (5G) of cellular networks may improve the localization accuracy by using trilateration techniques as time difference of arrival (TDOA) for reaching accuracies below one meter. The positioning precision for TDOA can be degraded by the main factors such as multipath propagation, synchronization errors, the gNodeBs position uncertainties and geometry of the network. Based in the knowledge of the probability density functions (PDF) of these main sources of uncertainty, it is implemented a surrogate model based in the Polynomial Chaos Expansion (PCE) of the Nonlinear Least Squares estimator (NLS) for positioning. This modeling reduces the computational cost for localization considering the uncertainty the input parameters and allows to obtain the PDF response of the system based in the uncertainty propagation through the model. The evaluation of 5G positioning by confidence regions of the PDF response of the system is considered under multipath propagation in 5G typical channels, synchronization errors and position gNodeB uncertainties as input parameters of the model. For the validation of simulations the results are compared with Monte Carlo simulations. Localisation and Tracking
TD(20)12007 Joint statistics of urban clutter loss and building entry loss at 3.5 GHz and 27 GHz – from measurement to modelling Richard Rudd, Xiaomin Meng, Victor Ocheri, Dehao Wu, Maziar Nek Empirical propagation models have been developed within the ITU-R for building entry loss and for urban clutter loss. At present these mechanisms are considered separately, but, in practice, will generally be combined. Initial measurements at 3.5 GHz and 27 GHz are reported here which suggest that the effects cannot be considered as multiplicative, and a simple asymptotic model is proposed for their combination. DWG1: Radio Channels
TD(20)12008 Channel Extrapolation in FDD Massive MIMO: Theoretical Analysis and Numerical Validation François Rottenberg, Rui Wang, Jianzhong Zhang and Andreas F. Molisch Downlink channel estimation in massive MIMO systems is well known to generate a large overhead in frequency division duplex (FDD) mode as the amount of training generally scales with the number of transmit antennas. Using instead an extrapolation of the channel from the measured uplink estimates to the downlink frequency band completely removes this overhead. In this paper, we investigate the theoretical limits of channel extrapolation in frequency. We highlight the advantage of basing the extrapolation on high-resolution channel estimation. A lower bound (LB) on the mean squared error (MSE) of the extrapolated channel is derived. A simplified LB is also proposed, giving physical intuition on the SNR gain and extrapolation range that can be expected in practice. The validity of the simplified LB relies on the assumption that the paths are well separated. The SNR gain then linearly improves with the number of receive antennas while the extrapolation performance penalty quadratically scales with the ratio of the frequency and the training bandwidth. The theoretical LB is numerically evaluated using a 3GPP channel model and we show that the LB can be reached by practical high-resolution parameter extraction algorithms. Our results show that there are strong limitations on the extrapolation range than can be expected in SISO systems while much more promising results can be obtained in the multiple-antenna setting as the paths can be more easily separated in the delay-angle domain. DWG2: PHY Layer
TD(20)12009 Tracking of Reflection Points for Improved Dynamic Ray Tracing Florian Quatresooz, Simon Demey, Claude Oestges Ray tracing is a powerful tool to obtain deterministic descriptions of communication channels, and can be applied to channels with high level of mobility. However, performing ray tracing simulations at each discrete time instant is computationally expensive. Therefore, a new approach is proposed to extrapolate results obtained from a single ray tracing simulation. It relies on the tracking of interaction points (e.g. reflection points), which enables an analytical prediction of the evolution of any ray identified during an initial ray tracing simulation. The performance of this new approach is illustrated on a few examples, and a gain of computation time of two orders of magnitude is found, while ensuring an accuracy of the positions of the reflection points close to the nanometer. DWG1: Radio Channels
TD(20)12010 Analysis of 3D Deafness Effects in Highly Directional mmWave Communications Olga Chukhno, Nadezhda Chukhno, Olga Galinina, Yuliya Gaidamaka, Sergey Andreev, Konstantin Samouylov In this paper, we address a problem of 3D directional deafness, which may arise for millimeter-wave (mmWave) devices, e.g., in the contention-based access period of the IEEE 802.11ad/ay protocols. To evaluate the probability of 3D deafness, we develop an analytical framework based on stochastic geometry methods. In particular, we study a minimal feasible set of devices equipped with highly directional antennas with an arbitrary antenna pattern and provide an analytical expression for the distance dependent 3D directional deafness probability. To abstract away from particular antenna patterns, we propose an analytically tractable model of an antenna pattern that is given by a piece-wise linear function of the beamwidth. Using this tractable equation, we derive a corresponding closed-form lower bound for the deafness probability that serves as an approximation for an arbitrary antenna with the same half-power beamwidth. Finally, we study the effects of antenna settings on the deafness probability and derive a scaling law for its lower values. DWG3: NET Layer
TD(20)12011 Achievable Synchronisation Gain in Uncalibrated Large Scale Antenna Systems Jens Abraham, Torbjörn Ekman Large scale antenna systems are used to exploit spatial multiplexing gains in massive MIMO systems. To realise those gains, channel state information has to be acquired at a base station. However, an initial control channel has to be provided to synchronise time and frequency at the user. This control channel should be undirected to cover the base stations operational area and can therefore not exploit the coherent array gain without additional strategies. Beam sweeping has been proposed to provide increased spatial coverage. Its performance for large scale antenna systems in Rayleigh and Rician fading environments is analysed. Even an orthogonal basis of antenna weights for full spatial coverage can not provide the full array gain. The results quantify the gap between achievable synchronisation and full array gain for uncorrelated antennas. Closed form solutions for the distribution of the gain gap under Rayleigh fading conditions are derived. DWG1: Radio Channels
TD(20)12012 Stochastic Geometry Modeling for UAV Relay Networks François De Saint Moulin, Charles Wiame, Claude Oestges, Luc Vandendorpe We consider a relay network based on Unmanned Aerial Vehicles (UAV) for a simple two-hop scenario. Macro Base Stations (MBS) and UAV Relay Nodes (RN) are modeled using independent Homogeneous Poisson Point Processes. All the links are either Line-of-Sight (LOS) or Non Line-of-Sight (NLOS), and they are subject to path-loss, shadowing and small-scale fading. Using Stochastic Geometry (SG), we give an expression of the coverage probability for a typical User Equipment (UE). This model is validated using Monte Carlo (MC) simulations. Finally, for an interference scenario, the impact of the RN height or density is analyzed using the developed mathematical expressions. It shows that a joint design of these two parameters permits to achieve the best coverage probability for a given Signal to Interference Ratio (SIR) threshold. DWG2: PHY Layer
TD(20)12013 Path Loss Model Validation for 5G NR based on Real Deployment Measurements Alberto Alvarez Polegre, Raquel Perez Leal, Jose Antonio Garcia Garcia, Ana Garcia Armada With the standardization of the fifth generation (5G) of mobile communications technology, 5G New Radio (NR), telecommunication providers and operators slowly started to deploy their network equipment while hardware manufacturers released the very first compatible user terminals. These deployments are rapidly increasing and first-hand information about performance is required for network optimization. In this work, results and performance evaluation based on testing in real environments under a 5G commercial network are presented. These measurements suppose some of the very first testings which can indeed show insights about the performance of the new standard. In addition, the outcome from the testing is compared with that one obtained with the path loss model employed for the simulation of these networks showing how accurate this mathematical formulation can be. DWG2: PHY Layer
TD(20)12014 Physical Modeling for Device-Free Localization exploiting Multipath Propagation of Mobile Radio Signals Martin Schmidhammer, Michael Walter, Christian Gentner, Stephan Sand This work proposes a model to describe the impact of a target on the received power of a multipath component (MPC). The physical propagation path of an MPC is decomposed geometrically and is described by direct propagation paths between physical and virtual nodes. Using the scalar theory of diffraction, the impact of a target on the electric field can be calculated for each component, individually. Thereby, the model relates alternations of the received power of MPC to the location and orientation of the target, which allows device-free localization systems to exploit multipath propagation. The model is evaluated for a single link scenario of one specular reflection. A comparison of modeled attenuation results to wideband measurement data qualitatively confirms the applicability of the proposed model representing target-induced attenuation. DWG1: Radio Channels,Localisation and Tracking
TD(20)12015 Prediction of Diffuse Scattering Characteristics by Physical Optics Approach in 32 GHz band Kentaro Saito, CheChia Kang, Panawit Hanpinitsak, Jun-ichi Takada As the start of the commercial service of the fifth-generation (5G) system, millimeter-wave wireless communication is expected to be more common in the mobile communication field. It is known that the diffuse scattering of the propagation wave becomes more severe in those high-frequency bands because the roughness and microscopic structure of the reflecting surface is not negligible compared to the wavelength of the wave. Therefore, understanding how the microscopic structures of the surface affect scattering characteristics is important to develop the prediction method of the propagation channel for the system performance evaluation. In this TD, we conducted the diffuse scattering measurements in 32 GHz band by the virtual array-based channel sounder. We also calculated the propagation channel by the Physical Optics (PO) approach from the detailed three-dimensional environment model measured by the laser scanner. The result showed that the PO approach can predict the angular characteristics of the diffuse scattering quite accurately. Further investigation in various propagation scenarios is planned to clarify the feasibility of our prediction approach. DWG1: Radio Channels
TD(20)12016 Accounting for the varying supply of renewable energy sources when designing wireless access networks: solar, wind and geothermal energy Margot Deruyck, Silvia Bova, Michela Meo, Wout Joseph Traditionally, we rely highly upon fossil fuels for our energy provisioning, but there are drawbacks to using these fossil fuels: the risk for depletion in the future, the increased cost as already observed during the last few years, and the high impact on climate change. One virtually carbon-neutral alternative to fossil fuels are renewable energy sources, like solar, wind, and geothermal energy. In this TD, we investigate the energy and network performance of a wireless acces network powered either by the traditional electricity grid, a photovoltaic panel system, a wind turbine system, and a geothermal system or by combining the above mentioned energy sources. An energy-aware management system for the future wireless access network is proposed. This system consists of the management of the energy provisioning and storage system and the application of the proposed energy-saving strategies which aim to reduce the energy footprint through the traditional grid in case a renewable energy shortage occurs. To evaluate the network’s performance, this TD proposes a deployment tool with the above described energy-aware management system. EWG-RA: Radio Access
TD(20)12017 Impact of Azimuthal Antenna Pattern Sampling and Variation on Throughput Measurements Andrés Alayón Glazunov, Madeleine Schilliger Kildal, and Jan Carlsson Presented is a numerical study of the impact of the antenna pattern sampling resolution on the accuracy of Over-The-Air (OTA) throughput measurements. More specifically, a Line-Of-Sight (Random-LOS) testing scenario is addressed. The communication throughput is evaluated as the Probability of Detection (PoD) of a single bitstream based on the ideal digital threshold receiver model. The maximum deviation of throughput efficiency is computed as a function of the azimuthal sampling resolution for various generic antenna gain patterns. The coefficient of variation of the antenna gain pattern is introduced to evaluate the impact of azimuthal sampling. The presented approach can be used to define the sampling resolution of the throughput performance of a device under test in Random-LOS OTA. EWG-OTA: Over-The-Air testing
TD(20)12018 System Development and Experimental Validation of a Long Range Ultra-Wideband Channel Sounder Allan Wainaina Mbugua, Wei Fan, Xuesong Cai, Yun Chen, Wei Wang, Kim Olesen, Gert Frølund Pedersen In a wireless communication system, the radio propagation channel is a complicated component to characterize. Channel sounding equipment thus has to meet specific criteria to extract the desired channel parameters. In this paper, we outline the development and validation of an ultra-wideband (UWB) vector network analyzer (VNA) based channel sounder using radio-over-fiber (RoF) techniques. Three methods of de-embedding phase errors due to hardware impairments are demonstrated and validated via back to back measurements. The bidirectional scheme utilizing optical circulators is shown to have a superior performance over the two-branch unidirectional and the two-branch bidirectional schemes. Therefore, the bidirectional scheme utilizing optical circulators is proposed to achieve a long range ultra wideband channel sounder based on the VNA. DWG1: Radio Channels
TD(20)12019 Vehicular multi-node channel sounding with a large vehicle obstruction Stefan Zelenbaba, David Löschenbrand, Markus Hofer, Anja Dakić, Benjamin Rainer, Gerhard Humer, Thomas Zemen Multi-node channel sounding enables simultaneous measurement of multiple wireless channels. This drastically reduces the amount of resources required for measurement campaigns and comes as an advantage in analyzing complex systems and scenarios, especially when it comes to rapidly time-varying wireless channels present in many applications envisioned for 5G, such as vehicular communications. In this paper we present the results of the first vehicular multi-node channel sounding measurement campaign. The measurements include two scenarios with three sounding nodes mounted into moving vehicles, and a double-decker coach acting as an obstruction. The time-varying statistical properties of links are compared for each scenario, and channel modeling parameters are provided for a passenger coach obstruction in terms of path loss and channel dispersion. DWG1: Radio Channels,DWG2: PHY Layer
TD(20)12020 Frame Error Rate Measurement Method for the Geometry Based System Level Simulation of Vehicular Communication Links Anja Dakić, Markus Hofer, Benjamin Rainer, David Löschenbrand, Stefan Zelenbaba, Thomas Zemen The reliability of data exchanged between vehicles strongly depends on the wireless communication link properties. For a large-scale system level simulation, the frame error rate (FER) on each individual link depends on the specific implementation of the transmitter and receiver, their movement as well as the geometry of the scattering environment. Currently available FER models for system level simulations are strongly simplified leading to biased results in non-stationary vehicular scenarios. We use a geometry based stochastic channel model (GSCM) to determine the delay and Doppler spread as well as the signal-to-noise ration (SNR) on each link within the system level simulation. The FER for each link is provided by the measured parameters of a real modem hardware (HW) so that we can obtain realistic results in highly time-variant non-stationary vehicular scenarios (hardware in the loop,

HiL). In this work we present a method to obtain the FER of a specific modem HW under different delay and Doppler dispersion as well as signal-to-noise ratios using a geometry-based channel emulator. The delay and Doppler dispersion, as well as the attenuation parameter range of the GSCM is quantized into finite steps and the FER for each of these data points is automatically obtained by our measurement setup. With this methodology an objective performance characterization of wireless vehicular modems for different standards such as IEEE 802.11p, LTE vehicular or 5G can be obtained in complex vehicular scenarios.

DWG1: Radio Channels, DWG2: PHY Layer
TD(20)12021 Joint Overlapping Ratio and Power Allocation with User Fairness in Partial Non-Orthogonal Multiple Access (P-NOMA) Nann Win Moe THET and Mehmet Kemal OZDEMIR In power-domain non-orthogonal multiple access (NOMA), since many users are able to utilize a single frequency subcarrier with different power levels, user interference occurs if successive interference cancellation (SIC) at the receiver is not performed perfectly. To reduce the amount of interference among NOMA users, recently an alternative approach called partial-NOMA (P-NOMA) was proposed. In this approach, the system allows partially overlapped bandwidth of the users and enables them to use NOMA in the overlapped region while the users in the non-overlapped bandwidth are arranged to utilize orthogonal multiple access (OMA). What should be the amount of overlapping ratios and the corresponding power levels still needs further research. In this paper, we propose an algorithm for joint allocation of overlapping ratios and power in P-NOMA system, which is based on gradient search, with the maximum sum-rate objective and user fairness constraint. Simulation results show that the proposed algorithm, which has lesser complexity than exhaustive search, obtains the optimum overlapping ratios and power allocation coefficient such that the maximum sum-rate of the P-NOMA is higher than that of the conventional NOMA while the target user fairness of 0.7 based on Jain’s index is achieved. DWG2: PHY Layer
TD(20)12022 Antenna-Generic Mode Channel: What, Why, How? Yang Miao This paper explains what is antenna-generic mode channel, why we need it, how to obtain and use it. This paper is based on previous studies that establishes the analytical model and analyzes the statistical

behaviors of multimode channels in spherical vector wave (SVW) domain based on the microcellular radio channel measurement in downtown Helsinki at 5.3 GHz band. The multimode channel is the representation of radio wave propagation in the form of the SVW mode coupling between the transmit and receive antennas. The multimode

channel does not rely on particular realizations of antennas at link ends, since any transmitting/receiving/scattering fields associated with an antenna can be modeled as a weighted sum of SVW modes where different antennas have different mode weights. The multimode channels are converted from the plane wave channel model parameters

that are extracted from measured channels of coherent snapshots along 6 different routes in Helsinki. Based on the analysis of various first and second order statistics of the multimode channels, the main findings can be summarized as follows: 1) the multimode channels are

power imbalanced; 2) the envelope short-term fading statistics of the multimode channels can be described with Rician probability distributions with varying K-factors; 3) the auto-correlations of multimode channels along the spatial translation of a mobile node in a propagation environment present varying coherent distances; 4) the

cross-correlations of multimode channels vary with the spatial translation too. The obtained results and the proposed multimode channel model provide invaluable insights into the design of antenna systems tailored to a specific propagation environment. Indeed, antenna systems at both link ends can be devised such that the multimode channels with higher power, larger coherent distance and

smaller cross-correlation are excited resulting in multiple input multiple-output antenna systems that exploit efficiently the degrees of freedom of the propagation channel.

DWG1: Radio Channels
TD(20)12023 Joint statistical modeling of received power, mean delay, and delay spread for indoor wideband radio channels Ayush Bharti, Laurent Clavier, Troels Pedersen We propose a joint statistical model for the received power, mean delay, and rms delay spread, which are derived from the temporal moments of the radio channel responses. We begin by analyzing indoor wideband measurements from two different data sets. It appears that the temporal moments are strongly correlated random variables with skewed marginals. Based on the observations, we propose a multivariate log-normal model for the temporal moments, and validate it using the experimental data sets. The proposed model is found to be flexible, as it fits different data sets well. The model can be used to jointly simulate the received power, mean delay, and rms delay spread. We conclude that independent fitting and simulation of these statistical properties is insufficient in capturing the dependencies we observe in the data. DWG1: Radio Channels
TD(20)12024 Characterizing Drone-to-Machine UWB Radio Channel in Conscious Factories Vasilii Semkin, Enrico Maria Vitucci, Franco Fuschini, Marina Barbiroli, Vittorio Degli-Esposti, and Claude Oestges In this work, we present the results of Ultra Wide Band (UWB) measurements carried out in a real-world factory environment. Targeting digitized and intelligent industrial deployments, we mimic a scenario where the drone can be used as a supplementary tool for factory operation optimization and control. The results presented in this paper can be applied for radio channel characterization, i.e. link budget calculation and interference studies in real factories. The UWB transmitter is located on the drone, while the receiver is fixed on the ground. The measurements were performed at different locations over the 3.1-5.3 GHz band. The drone hovers and moves around the factory during the measurements. The power delay profile is measured at each drone position and the simple path loss model is introduced. The measurements are compared with conventional ground-to-ground measurements with the same settings. DWG1: Radio Channels
TD(20)12025 Calibration of Stochastic Channel Models using Approximate Bayesian Computation Ayush Bharti, Troels Pedersen Calibration of stochastic radio channel models is the process of fitting the parameters of a model such that it generates synthetic data similar to the measurements. The traditional calibration approach involves, first, extracting the multipath components, then, grouping them into clusters, and finally, estimating the model parameters. In this paper, we propose to use approximate Bayesian computation (ABC) to calibrate stochastic channel models so as to bypass the need for multipath extraction and clustering. We apply the ABC method to calibrate the well-known Saleh-Valenzuela model and show its performance in simulations and using measured data. We find that the Saleh-Valenzuela model can be calibrated directly without the need for multipath extraction or clustering. DWG1: Radio Channels
TD(20)12026 Maximum likelihood calibration of stochastic multipath radio channel models Christian Hirsch, Ayush Bharti, Troels Pedersen, Rasmus Waagepetersen We propose Monte Carlo maximum likelihood estimation as a novel approach in the context of calibration and selection of stochastic channel models. First, considering a Turin channel model with inhomogeneous arrival rate as a prototypical example, we explain how the general statistical methodology is adapted and refined for the specific requirements and challenges of stochastic multipath channel models. Then, we illustrate the advantages and pitfalls of the method on the basis of simulated data. Finally, we apply our calibration method to wideband signal data from indoor channels. DWG1: Radio Channels
TD(20)12027 A Real-time QoS-Demand-Aware Computational Resource Sharing Approach in C-RAN Mojgan Barahman, Luis M. Correia and Lúcio S. Ferreira This paper presents a dynamic resource sharing approach aiming at optimizing the computational resources performance of a baseband unit pool in a cloud radio access network. Based on the bargaining concept in game theory, resource sharing is formulated as an optimization problem taking quality of service, real-time demand and the minimum resources that are required to prevent BBU crashes into account. The performance of the proposed model is evaluated in terms of BBU fulfilment level, resource usage and efficiency over time. Simulation results, for heterogeneous services in a tidal traffic environment, demonstrate that the proposed model allocates the computational resources in proportion to the instantaneous demand of baseband units and the priority of the ongoing services. Results also show a minimum 95% enhancement in the efficiency of resource allocation in off-peak hours, compared to fixed allocation strategies based on peak-hour traffic demand. DWG3: NET Layer
TD(20)12028 LSTM-based method for LOS/NLOS identification in an indoor environment Alicja Olejniczak, Olga Błaszkiewicz, Krzysztof K. Cwalina, Piotr Rajchowski, Jarosław Sadowski Due to multipath propagation, harsh indoor environment significantly impacts transmitted signals which may adversely affect the quality of the radiocommunication services, with focus on the real-time ones. This negative effect may be completely overcome (e.g. resources management and allocation) or compensated (e.g. correction of position estimation in radiolocalization) by the LOS/NLOS identification algorithm. This paper investigates the idea of improving already existing LOS/NLOS classification method, based on a deep feedforward neural network, by the LSTM model which allows extracting and analysing time-related dependencies occurring in a radio channel. EWG-IoT: Internet-of-Things
TD(20)12029 Wireless Cable Testing for 5G Radios: A future-proof compact 5G radio performance test solution Wei Fan; Fengchun Zhang As the 5G ecosystem matures, the time for large-scale 5G radio commercialization is now. Thorough testing of 5G radios is essential before massive rollout. However, state-of-the-art testing methods have not kept pace with advances in antenna development. In this project, we aim to develop a low-cost wireless cable testing solution in a compact setup for 5G radios. The wireless cable solution for 2×2 MIMO LTE handset was proposed, implemented, experimentally validated, and published. This initial work has proved that the wireless cable method works in practice. In this TD, a novel close-form method to establish wireless cable connection for high-order MIMO radios is proposed. Our objective is that the proposed method can be executed in a compact anechoic box. Further, the solution should be generic (i.e. applicable for any commercial MIMO systems), future-proof (i.e. complexity does not scale up with MIMO system design) and fast (i.e. short calibration time). EWG-OTA: Over-The-Air testing
TD(20)12030 On Scattering and Specular Reflection from Smooth and Irregular Surfaces Fred Wagen, Alberto Loaiza Freirei, and Mark Beach Previous TDs including TD(19)11013 proposed a formulation to combine the use of specular reflection and Degli-Esposti (VDE) single-lobe directional scattering (Eq. in Fig 3.33 Chap 3-draft of the IRACON’s book) for radio propagation channel modeling. The proposed formulation, called GGXS, is inspired from many contributors to COST IRACON, the specular reflection from smooth surface, the radar equation and the computer graphics GGX model. The GGXS is reciprocal and leads to well-known equations for very small or large and smooth or rough facets. The GGXS was claimed to fit the results for facets of any size and any roughness. Preliminary comparisons with measurements conducted at Bristol University are discussed. It appears that using two components of the simplified and reciprocal version of the VDE model fits better the results than the GGXS formulation for a smooth metal plate. This unexpected result is claimed to be due to the antenna pattern used for the measurements. DWG1: Radio Channels
TD(20)12031 Wall penetration loss measurements for a small meeting room @28 GHz Christina Larsson, Martin Johansson, Sinh Nguyen In this paper we present wall penetration loss measurements for a small meeting room using both angular resolved measurements and measurements performed with omni antennas, all measurements are CW measurements at 28 GHz. To improve our indoor 3D models, we have performed a set of angular resolved measurements in office environment, here we present the results from small meeting room in our office landscape. The angular resolved measurements make it possible to evaluate the dominating propagation path when the LOS is blocked by plaster board, doors, whiteboards etc. By making omni antenna measurements in the same locations as the angular resolved measurements, it is possible to compare the results and evaluate the omni-synthesizing method used. DWG1: Radio Channels
TD(20)12032 On the Performance of NB-IoT Networks Served From Unmanned Aerial Base Stations Silvia Mignardi, Konstantin Mikhaylov, Chiara Buratti, Roberto Verdone We consider a Narrowband-IoT (NB-IoT) network where an Unmanned Aerial Vehicle (UAV) is used as an alternative to traditional static Terrestrial Base Stations (TBSs). In fact, UAVs may fly over the terrestrial

plane, where and when TBSs cannot provide the requested coverage and capacity, that means acting as Unmanned Aerial Base Stations (UABs). In order to connect to and serve as many ground nodes as possible, a proper trajectory design is fundamental. This paper studies an Orienteering Problem approach to design the UAB trajectory. In this

way, it can serve NB-IoT nodes which are clusterized in an uplink scenario. The model considers the protocol constraints on the number of resource units available on the UAB’s NPUSCH, and the data rate that it can provide to users.

EWG-IoT: Internet-of-Things
TD(20)12033 Analysis of the millimeter-wave urban channel properties from beamforming measurements and LiDAR-based simulations Mohammed Zahid Aslam, Grégory Gougeon, Yoann Corre, Jakob Belschner, Gnana Soundari Arockiaraj, Monika Jäger Ray-based deterministic models are able to provide reliable site-specific urban radio channel predictions at millimeter-wave frequencies, provided the computation is run on top of an accurate digital geographical data i.e. with sub-metric precision for the 3D contour of buildings, trees, and other major structures that may impact the propagation. This paper describes three different applications of such a ray-based model using building vectors and terrestrial LiDAR. 1) Analysis of the 60-GHz backhaul radio channel in urban canyoning and residential environments from together bi-directional beamforming measurements and simulations ; both the measurements and simulations have shown strong channel sparsity caused by the many in-street obstacles. Then, 2) Complementary characterization of the same 60-GHz urban backhaul channel by simulating extra (unmeasured) scenarios. And, 3) Investigation on a mesh backhaul network’s performance at 150 GHz : throughput statistics vs. antenna separation. DWG1: Radio Channels
TD(20)12034 E.M. Characterization of Construction Materials Using the Fabry-Pérot resonance method Leonardo Possenti, Juan Pascual-García, Vittorio Degli-Esposti, Antonio Lozano-Guerrero, Marina Barbiroli, Maria-Teresa Martinez-Inglés, Franco Fuschini, José-Víctor Rodríguez, Enrico Maria Vitucci, José-María Molina-García-Pardo Several frequency bands above 6 GHz are being proposed for next generation wireless systems, and the electromagnetic characteristics of many common construction materials at those frequencies still need to be determined. The knowledge of such characteristics is particularly relevant, especially in relation to the increasing use of deterministic propagation models for radio-channel characterization in 5G and beyond systems. In this study, the method based on Fabry-Pérot resonance inside materials’ slabs is applied for the evaluation of the complex permittivity of the material. Scope of the work is to assess the applicability of the method to different materials and frequencies using different setups, including a portable spectrum analyzer for on-site non-destructive measurements. Moreover, an improved procedure for the determination of the imaginary part of the complex permittivity is presented. DWG1: Radio Channels
TD(20)12035 Reconfigurable and Focused Surfaces and Channel Characterization at mmWave R. D’Errico, A. Clemente, F. Foglia Manzillo, M. Smierzchalski, A. Mudonhi, A. Guerra, F. Guidi In this TD we present antenna solutions based on focused surface for 5G and beyond technologies at mmWaves and sub-THz frequencies. Beamforming capabilities and channel characterization are shown. DWG1: Radio Channels
TD(20)12036 Off-Body Channel Dynamics for Walking or Running Users Kenan Turbic and Luis M. Correia This paper presents a geometry-based statistical channel model for off-body communications with dynamic users, walking or running. The model assumes static point scattering, with the scatterers distributed on a cylinder centered around the user, and employs a mobility model for wearable antennas based on Fourier series to take the effects of user’s motion into account. The model is developed for a general non-stationary channel, where the user’s relative position and orientation with respect to scatterers can change over time. However, the paper focuses on a special case with the directions of arrival assumed time-invariant. The influence of different aspects of wearable antenna motion on the channel variation dynamics is analyzed, by evaluating the local Auto-Correlation Function (ACF) for a uniform scattering scenario. The dynamic posture is found to result in a non-stationary channel for wearable antennas on the arms and legs, where the coherence time estimated from the local ACF is observed to change by more than 223 ms during a motion cycle, with the maximum value being by an order of magnitude larger than the minimum one. DWG1: Radio Channels,SEWG-IoT: Internet-of-Things for Health
TD(20)12037 A Study on Dual-Directional Mm-wave and THz Indoor Channel Characteristics Enrico M. Vitucci, Johannes M. Eckhardt, Vittorio Degli-Esposti, Thomas Kürner The dual-directional characteristics of propagation in a medium-size lecture room, are assessed in this work through directional measurements and ray tracing simulation at 3 different frequencies, 10 GHz, 60 GHz, and 300 GHz. Ray Tracing is used as a tool to interpret measurement results, but also as a model to simulate multipath propagation. For what concerns the latter aspect, ray tracing is calibrated vs. measurements and used to highlight the major characteristics and the role of the relevant propagation mechanisms at the different frequencies. DWG1: Radio Channels
TD(20)12038 Flight Measurement Campaign for the Ground-Air Channel in C-Band Daniel M. Mielke Unmanned Aircraft (UA) are expected to play a more and more important role in global aviation during the next years. Besides the “smart” onboard control equipment leading to a certain amount of autonomy of the vehicle, a reliable data link (“Command and Control”, C2-link) is a key enabler to control UA in civil airspace. This C2 link is used to exchange information between the UA and the remote pilot, for example positioning information, telemetry data or flight trajectories, respectively. None of the currently available aeronautical communication standards can fulfill the requirements for such a multi-user, multi-point datalink in terms of reliability, flexibility, data integrity, robustness and latency. The German Aerospace Center (DLR) initiated a flight measurement campaign to perform radio channel measurements of the terrestrial ground-air channel in C-band. Detailed knowledge on the behavior of the physical communication channel is crucial for an optimal design of a new communication system. Therefore, it is necessary to perform C-band channel measurements (aka “channel sounding”) and use the collected information to develop a channel model. In turn, this channel model can be used to optimize and evaluate the CDACS waveform design in simulations. The bandwidth used for the C-band channel measurements of this campaign was ~50MHz. Multiple flight routes and maneuvers are chosen to collect information on different flight scenarios, e.g. take-off and landing, hard banking and en-route. We furthermore propose an algorithm for the successive detection of multi path components in the received measurement data stream. The algorithm’s multi path detection capabilities are evaluated given artificially generated multi path signals. DWG1: Radio Channels,DWG2: PHY Layer
TD(20)12039 Theoretical and Emulated Performances of MANETs Using TDMA: Preliminary Results Yann Maret, Jean-Frédéric Wagen Vehicle to Vehicle MANET or VANET using scheduled slotted TDMA transmission might be beneficial to offer guaranteed QoS as compared to CSMA. Theoretical performance results are derived and compared to

results from emulations using the open source EMANE framework and OLSRd2. The emulation platform allows real time testing with “real” applications. Work in progress is reported.

DWG3: NET Layer
TD(20)12040 Data-driven construction of user utility functions from connection traces in LTE Antonio J. García, Carolina Gijón, Matías Toril, Salvador Luna Over the last years, there has been an increase in the number of services in mobile networks. Such an increase has forced operators to change their network management processes to ensure an adequate user Quality of Experience (QoE). A key component in QoE management is the availability of a precise QoE model for every service that reflects the impact of network performance variations on the end user experience. In this work, an automatic method is presented for deriving the Quality-of-Service (QoS) thresholds in several analytical QoE models from connection traces collected in a LTE network. These QoS thresholds reflect the minimum connection performance below which a user gives up its connection. The proposed method relies on the fact that user experience can be inferred from connection length in most services. Method assessment is performed with real connection traces taken from a live LTE network. Results confirm that packet delay or data throughput are critical factors for user experience in the analyzed services. DWG3: NET Layer,
TD(20)12041 Implementation of the innovative radiolocalisation system VCS-MLAT (Voice Communication System – Multilateration) Szymon Wiszniewski, Olga Błaszkiewicz, Alicja Olejniczak, Jarosław Sadowski, Jacek Stefański In the article the concept of the radiolocalization subsystem of VHF communication for aviation VCS-MLAT (Voice Communication System – Multilateration) is presented. The distributed localization system will estimate the position of the aircrafts by the audio signals transmitted in aircraft band (118-136 MHz). This paper presents the main assumptions of the project and describes the structure and scheme of the localization modules. Moreover, in the article the preparation to the final test in the real environment is presented. Localisation and Tracking
TD(20)12042 Deep Learning versus High-order Recurrent Neural Network based

Decoding: First Results

Werner G. Teich, Ruiqi Liu, and Vasileios Belagiannis Deep neural network (DNN) are known to be able to approximate highly complex functions. Structure and size of the DNN are typically found by trial and error. The weights of the DNN are obtained by a supervised or unsupervised training process, requiring a sufficiently large amount of (labeled) data. In the last decade, DNN have shown impressive results in various fields such as image classification, speech recognition, or playing the abstract strategy board game Go. Recently, an increased interest in the application of DNN to physical layer problems can be observed. We use a DNN for one-shot decoding of a simple convolutional (self-orthogonal) codes. Advantage of this use case is the pratically unlimited amount of labeled data for training. A disavantage is, that the number of code words to be learned increases exponentially with the dimension of the code. We compare the performance of the DNN based decoding with iterative threshold decoding (ITD). Here, a discrete-time recurrent neural network (RNN) is used as a computational model for ITD. Unwinding the RNN we arrive at a DNN with a special structure as defined by the RNN. The number of layers is given by the number of iterations we consider in the discrete-time RNN. With a training procedure we can optimize the performance ot this unwinded RNN (uRNN). The advantage of this approach is that the structure of the uRNN is determined by the structure of iterative threshold decoding. Only a few weights, which are shared within and between the layers, can and must be adopted to optimize the network. In this way we combine the advantages of both approaches, the structured approach of the RNN as a computational model on one hand as well as the training based optimization as given by a DNN, on the other hand. DWG2: PHY Layer
TD(20)12043 Accuracy Requirements for Cooperative Radar with Sensor Fusion Mehdi Ashury, Christian Eliasch, Thomas Blazek, Christoph Mecklenbräuker Reliability and robustness are the essential requirements for automotive radar systems. However an automotive radar system suffers from environmental conditions and interference. Applying a proper radar data fusion algorithm can significantly increase the detection probability and robustness. This article investigates the accuracy requirements based on the geometric parameters for cooperative radar sensors with central sensor fusion. The results show that a radar sensor fusion for cooperative radar can increase the detection probability and therefore the system robustness by using at least two radar sensors. Furthermore, results show that three to four sensors at a minimum distance of ten meters are sufficient for high quality estimation. At the same time the system requirements regarding the accuracy for every single radar sensor can be relaxed to a range accuracy as low as one meter standard deviation. EWG-IoT: Internet-of-Things,
TD(20)12044 Cooperative localization in indoor environment Olga Błaszkiewicz, Krzysztof K. Cwalina, Alicja Olejniczak, Piotr Rajchowski, Jarosław Sadowski In the article problem of cooperative localization in the indoor environment is presented. The main goal of the conducted research is to estimate the position of a mobile node (MN), which is outside of some reference nodes (RNs) communication range and at the same time another mobile node is going to act as a temporary reference node (TRN). Such operation will allow extending area covered by positioning service or minimizing the position estimation errors. For investigating the cooperative credibility issue, the simulation tool, based on a real measurement campaigns which have taken in two types of indoor environment, was evaluated. The tool will be used to develop and propose an algorithm dedicated for indoor cooperative localization systems. EWG-IoT: Internet-of-Things, Localisation and Tracking
TD(20)12045 Beam Selection for Hybrid Beamforming with Multi-Path

Propagation: Novel Learning Architectures and Sufficient


Carles Antón-Haro, Xavier Mestre In this paper, we investigate the applicability of deep and machine learning (ML/DL) techniques to beam selection problems. Specifically, we adopt a hybrid beamforming architecture comprising an analog beamforming (ABF) network followed by a zero-forcing (ZF) baseband processing block. The goal is to select the element in the ABF codebook yielding the highest sum-rate. The multi-antenna system operates in 5GNR’s Frequency Range 2 and, accordingly, the ML/DL-based architecture has been designed to explicitly consider a number of practical aspects of such mmWave communication systems. In particular, the presence of multi-path propagation along with the use of multi-carrier signals precludes the use of (single) angle-of-arrival information as an input to the learning system, as we did in previous works. Here we investigate alternative sufficient statistics (SS) such as the singular vector/values of the (multi-carrier) channel matrix or the covariance matrix (and a number of variants). Besides, the novel ML/DL architecture allows to directly estimate the aforementioned SS with the ABF in use for data transmission at each time instant. This enables a continuous operation of the system and avoids the spectral efficiency losses associated to periodically switching to a dedicated ABF for SS estimation. Computer simulation results illustrate the performance of several ML/DL approaches (k-nearest neighbors, support vector classifiers, multilayer perceptron) in realistic 5G scenarios. DWG2: PHY Layer
TD(20)12046 Capacity/cost trade-off for 5G small cell networks in the UHF and SHF bands Emanuel B. Teixeira, Anderson R. Ramos, Marisa S. Lourenço, Fernando J. Velez and Jon M. Peha To fulfil the demand for high data rates from a wide number of users, higher frequencies can be used to provide the required capacity but with a different cost structure. 5G allows for very high data rates, which needs large bandwidths and requires very high throughput. This paper studies the economic trade-off of small cell networks deployed in Ultra High Frequency (UHF) and Super High Frequency (SHF) bands. Aiming at evaluating the variation of the carrier-to-noise-plus-interference ratio with the cell radius one considers the two-slope urban micro Line-of-Sight (UMiLoS) path loss model (ITU-R 2135 Report). The system capacity is analysed by the implicit function formulation to compute the supported cell throughput through the mapping of the PHY throughput into the step distances that correspond to the minimum carrier-to-interference-plus-noise ratio for each consecutive modulation and coding scheme. The variation of the equivalent supported throughput with the cell size at the 2.6, 3.5 and 5.62 GHz frequency bands facilitates to study the influence of the carrier-to-noise-plus-interference ratio in the dimensioning process. It is possible to conclude that, for the shortest cell radii, the profit is very low, starting to increase at a distance equal to the ratio between the break-point distance and the co-channel reuse factor attaining maxima for values of the cell radius approximately equal to 310, 390 and 740 m, at 2.6, 3.5 and 5.62 GHz, respectively (by assuming that the 5.62 GHz frequency band is unlicensed).
TD(20)12047 Comparative Analysis of Multicarrier Waveform Candidates Considering Hardware Implementation in 5G Bahram Khan, Rooderson Martines de Andrade and Fernando J. Velez To fulfil the requirements of 5G vision of “everything everywhere and always connected”, a new waveform must contain the features to support a greater number of users on high data rate. Although Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in the 4th generation, but it can hardly meet the needs of 5G vision. However, many waveforms have been proposed to cope with new challenges. In this paper, we have presented a comparative analysis of several waveform candidates (FBMC, GFDM, UFMC, F-OFDM) on the basis of complexity, hardware design and other valuable characteristics. We evaluated the complexity comparison of these waveforms. Moreover, we demonstrated the suitability of F-OFDM on the basis of flexibility, Latency and Relaxed synchronization as compared to other waveforms.