Diego Dupleich

• Master of Science
• Research Associate at Technische Universität Ilmenau

Understanding the hardware impairments and the effect of the postprocessing algorithms on an unknown channel sounder (CS) requires a comparison with a calibrated instrument with a known error model. In this study, we use a vector network analyzer (VNA), with error models, and theoretical calculations to characterize two correlation-based purpose-de...

To make indoor industrial cell-free massive multiple-input multiple-output (CF-mMIMO) networks free from wired fronthaul, this paper studies a multicarrier-division duplex (MDD)-enabled two-tier terahertz (THz) fronthaul scheme. More specifically, two layers of fronthaul links rely on the mutually orthogonal subcarreir sets in the same THz band, wh...

To liberate indoor industrial cell-free massive multiple-input multiple-output (CF-mMIMO) networks from wired fronthaul, this paper proposes a multicarrier-division duplex (MDD)-enabled two-tier terahertz (THz) fronthaul scheme. In our scheme, two layers of fronthaul links rely on themutually orthogonal subcarrier sets in the same THz band, while a...

In this paper, we present the ray tracing (RT) simulation in the 3D model of one highly dense clutter industrial hall, which is scanned by laser scanner and reconstructed based on accurate point cloud. The whole processing chain from the scanning of the physical environment to running the simulation is presented in detail. To validate the simulatio...

This chapter is the perfect introduction to get an overview of THz channel sounder technologies. Additionally, all relevant state of the art and references for the field of THz channel sounding are summarized. The aim of the THz sounder chapter is to create a basic understanding of measurement setups and challenges for the measurement of the electr...

A framework is proposed for developing and evaluating algorithms for extracting multipath propagation components (MPCs) from measurements collected by sounders at millimeter-wave (mmW) frequencies. To focus on algorithmic performance, an idealized model is proposed for the spatial frequency response of the propagation environment measured by a soun...

Development of a comprehensive channel propagation model for high-fidelity design and deployment of wireless communication networks necessitates an exhaustive measurement campaign in a variety of operating environments and with different configuration settings. As the campaign is time-consuming and expensive, the effort is typically shared by multi...

In this paper, impact of antenna directivity and bandwidth on the small scale fading statistics have been analyzed for millimeter-wave (mmWave) radio channels. For this purpose, small-scale fading measurements at the mmWave frequency band (58–62 GHz) are carried out using transmit and receive antennas with different antenna directivities (emulated...

Radio access at mm-waves has been subject of intensive research in the latest years. However, within the initial deployment of 5G, mm-waves are still relegated and there is a generalized idea that the mm-wave channel for radio access, in comparison to the sub-6 GHz channel, is not only sparse but also troublesome for outdoor applications. In the pr...

Wireless vehicular communications and sensing technologies are key to enabling more advanced intelligent transportation systems (ITSs) with improved safety and efficiency. Within the realm of wireless communication, millimeter-wave (mmwave) technology has recently received much attention, providing rich spectrum resources to support the timely tran...

In the present paper we introduce the results of simultaneous multi-band ultra-wideband measurements at 6.75, 30, and 60 GHz in a street canyon scenario under LOS in Germany. This is the first part of a street canyon measurements series using the same channel sounder in different parts of the world. The aim of these measurements is to analyse and c...

In this paper, a novel three dimensional (3D) hybrid ray tracing (HRT) method for wave propagation simulation for large indoor and small cell urban environment is proposed. HRT combines two image based ray tracing (RT) methods: "standard" ray tracing (i.e., the rigorous and conventional image ray tracing) with high accuracy and "intelligent" ray tr...

Polarization diversity at mm-waves is under consideration for the new 3GPP release. Since mm-waves systems have higher resolution in the time and angular domain, more accurate intra-cluster models are needed, in which path properties as polarization becomes more deterministic. In the present paper we discuss the limitations of the current modelling...

We introduce simultaneous multi-band ultra wide-band directional measurements at 6.75 GHz, 30 GHz, and 60 GHz in an indoor environment with different visibility conditions. Large scale parameters and path-loss has been analysed for the different bands considering the propagation channel, and later the influence of the system aspects in the radio ch...

Hybrid, mixed analogue/digital beam-forming architectures are a central research topic for the development of mm-wave communication for fifth generation. Most approaches are based on phase shifters in the analogue part, which are inherently narrowband. In this study, the authors evaluate the effects and performance of narrowband beam-steering on wi...

Second-order statistics of indoor directional channels are investigated using millimeter wave (mmWave) band (30.4 to 37.1 GHz) ultra-wideband (UWB) channel measurements. Considering two main mmWave system assumptions (high bandwidth and high beamforming gain), this paper aims to investigate validity of the Rayleigh/Rice fading models for the cluste...

Vehicle-to-Vehicle (V2V) channels exhibit unique properties, due to the highly dynamic environment and low elevation of the antennas at both ends of the link. Of particular importance for the behavior of V2V channels, and consequent reliability of the communication link, is the severity and dynamics of blockage of both line-of-sight (LOS) and other...

Using Sum-Of-Cisoids (SOC) principle along with a deterministic parameter computation method, this paper provides studies on modeling of the intra-cluster number of scattered multi-path components (MPC) $N$ and their amplitudes $c_n$. Modeling objective is to ensure that the fading statistics of the receive (Rx) signal magnitude of the measured bea...

In the present paper we analyse the system performance and effects of narrowband beam-steering on the equivalent channel at mm-waves considering aspects as bandwidth and number of antennas. Using ray-tracing at 60 GHz, we show that neglecting the spatial-wideband effects on the channel models overestimates the delay spread reduction and achievable...

This contribution presents propagation measurements at 60 GHz in indoor non-line of sight scenarios. Besides analysing the measurements, the authors have considered several system aspects, such as bandwidth and directivity in order to investigate the small-scale behaviour of the radio channel after beam-forming. The results show that due to the hig...

This paper presents 70-77 GHz wideband channel characteristics of delay, spatial and polarimetric domains for small office and entrance hall scenarios. Based on measured multi-dimensional power spectra of delay, directions ( i.e. azimuth and elevation) of departure and of arrival, multipath clusters were detected using the K-means, threshold-based,...

Our goal is to identify if limited channel-state information is sufficient in order to mitigate interferences between the stations of a wireless mobile backhaul network, which is especially of great importance if the network employs full-duplex operation or terrestrial and satellite links sharing the same spectrum. We analyze and compare the signal...

In this paper, directional small scale fading measurements are used to extract the fading statistics of the received signal magnitude and the parameters of the underlying stochastic (Rayleigh/Rician) model. After that sum-of-cisoids (SOC) principle is used to model the deterministic samples (channel snapshots) of the stochastic model with a special...

Frequency bands above 6 GHz are being considered for future 5G wireless systems because of the larger bandwidth availability and of the smaller wavelength, which can ease the implementation of high-throughput massive MIMO schemes. However, great challenges are around the corner at each implementation level, including the achievement of a thorough m...

Large absolute channel bandwidths at millimeter wave (mmWave) frequencies and more directional antenna gains may lead to quasi-deterministic (less random) channel fading behavior. Cross polarization discrimination (XPD) is an attribute related to the channel fading characteristics. In narrow-band channels, it is usually modeled as a log-normal rand...

If a channel is frequency dependent then Uncorrelated Scattering (US) (a narrow-band assumption) don't hold. This has a significant impact at the considered channel modeling methodology as delay and angular dispersion of waves can no longer be studied independently because the small scale fading of individual multipath components become correlated....

A wireless channel is always composed of both deterministic and stochastic multi-path components. A high Rician K-factor increases the contribution of deterministic channel components, thereby reducing the significance of stochastic parts of a channel. This paper focus at the investigative analysis of fading depth and K-factor to analyze the determ...

In the present paper we analyse small-scale fading of reflections at 60 GHz using different antennas and bandwidths. The aim is to investigate the deterministic property of the channel in view of modelling and deployment of systems with larger bandwidths and higher directivity. We have investigated the scattering effect of a reflection on a wall em...

The World Radiocommunication Conference 2015 (WRC-15) identified a number of frequency bands between 24 and 86 GHz as candidate frequencies for future cellular networks. In this article, an extensive review of propagation characteristics and challenges related to the use of millimeter wave (mm-wave) in future wireless systems is presented. Referenc...

In the present paper we introduce the architecture of a hybrid digital / analog beam-forming with polarization compensation. To evaluate the performance of this architecture we use double-directional, ultra wideband dual- polarized channel measurements at 70 GHz that have been carried out in a small-office environment scenario at the TU Ilmenau. Di...

The vision of multi Gbit/s data rates in future 5G networks requires the change to millimeter wave (mm-Wave) frequencies for increasing bandwidth. As a consequence, new technologies have to be deployed to tackle the drawbacks of higher frequency bands, e.g. increased path loss. Development and verification of those novel technologies requires chann...

Beam-forming at millimeter wave frequencies (mmwave) is a key technology to fulfill the fifth generation (5G) high data rate requirements. In this paper, we describe a novel hybrid architecture for mm-wave beam-forming, which addresses the mm-wave specific propagation channel characteristics that are identified in recent measurement campaigns. This...

According to the current prospect of allocating next generation wireless systems in the underutilized millimeter frequency bands, a thorough characterization of mm-wave propagation represents a pressing necessity. In this work, an “item level” characterization of radiowave propagation at 70 GHz is carried out. The scattering properties of several,...

Double-directional, ultra wideband dual-polarized channel measurements at 70 GHz have been carried out in a small-office environment. The aim of these measurements is to study the temporal, directional, and polarization properties of the channel for modelling purposes of the future wireless communication systems at mm-waves. A highly deterministic...

Owing to the limitation in bandwidth of currently used frequency bands, future fifth generation (5G) mobile networks will need to operate at higher frequencies. However, one important step in the research activities for the next generation of mobile networks is the broadband fully polarimetric analysis of the multipath propagation in dynamic single...

A wideband, fully polarimetric and directional radio channel sounding campaign conducted at 70 GHz is presented. Measurement site was chosen as an entrance hall, featuring femtocell size. Transmitter and receiver were placed according to an access-point scenario. Initial large-scale parameters like excess-delay, delay-spread and angular spread are...

Pencil-beam forming techniques based on large antenna arrays are becoming a crucial asset to cope with the very high throughput density requirements and high path-loss constraints of future millimeter-wave gigabit-wireless applications. Directional, polarimetric 60 GHz indoor measurements are used in the present work to modify and calibrate a 3D ra...

The use of large-size antenna arrays to implement pencil-beam forming techniques is becoming a key asset to cope with the very high throughput density requirements and high path-loss of future millimeter-wave gigabit-wireless applications. Sub-optimal beamforming strategies based on search on discrete set of beams (steering vectors) are proposed an...

Directional, dual-link, quad-polarized 60GHz channel measurements have been carried out in a small-office environment. Purpose of the measurements is to study the directional properties of the channel in view of future multi-gigabit system adopting beam-forming or macro-diversity solutions. The impact of polarization on the characteristics of the c...

Increasing data rates in mobile networks require new technologies for the next generation of mobile communication systems such as massive MIMO, device-centric architectures, smarter devices, machine-2-machine communication etc. However, one important step to reach the goal of 100 GBit/s will be use of higher bandwidth. Owing to the limitation in ba...

Owing to the increasing data rates, future 5G mobile networks will need to operate at higher frequencies and bandwidths. To investigate new techniques for those networks, channel sounding is essential for measuring and analysing the multipath propagation in single and multi-user situations under time-variant shadowing environments. This requires a...

This paper addresses the mitigation of non-linearly induced interference in reconfigurable wideband direct down-conversion receivers using digital signal processing techniques. Multi-mode and multi-band transceivers are widely used nowadays. However, due to their aim to be flexible and reconfigurable, they lack of high selectivity and are more sens...