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Trajectory-Aided Maximum-Likelihood Algorithm for Channel Parameter Estimation in Ultrawideband Large-Scale Arrays

Millimeter-wave with ultrawide bandwidth available and ability to pack massive number of antennas in a small area is considered the key enabler for future generation communication systems. Accurate understanding and modeling of the ultrawideband propagation channel with large-scale array configuration is essential. In this contribution, a realistic spherical-propagation signal model considering th

Measurement-based Double-Directional Polarimetric Characterization of Outdoor Massive MIMO Propagation Channels at 3.5GHz

Massive multiple-input multiple-output (MIMO) is a key technology for 5G wireless communications since it can improve network throughput, capacity, spatial efficiency, etc. utilizing large-scale antenna arrays. In this paper, we study the direction of departure (DOD) and direction of arrival (DOA) power spectra and the angular spreads for suburban line-of-sight (LoS) environment. Our study is base

A USRP-Based Channel Sounder for UAV Communications

The unmanned-aerial-vehicle (UAV) has attracted great interests in both civil and military applications, due to its low cost, flexibility and ability to establish seamless coverage. In this paper, a Universal Software-defined Radio Peripheral (USRP) based channel sounding system for characterizing the UAV communication channel is introduced, which can be applied in both active and passive measurem

Phase-Compensated Optical Fiber-Based Ultrawideband Channel Sounder

In this article, a novel vector network analyzer (VNA)-based ultrawideband (UWB) channel sounder using radio-over-fiber (RoF) techniques is presented. Benefiting from the usage of optical fiber cable, the measurement range and the dynamic range are significantly increased compared with the conventional coaxial-based VNA system. Specifically, using RoF increases the dynamic range to a maximum of 11

Low Altitude Air-to-Ground Channel Characterization in LTE Network

Low altitude unmanned aerial vehicle (UAV)-aided applications are promising in the future generation communication systems. In this paper, a recently conducted measurement campaign for characterizing the low-altitude air-to-ground (A2G) channel in a typical Long Term Evolution (LTE) network is introduced. Five horizontal flights at the heights of 15, 30, 50, 75, and 100 m are applied, respectively

Development and Experimental Validation of an Ultra-wideband Channel Sounder

Vector network analyzer (VNA) has been extensively utilized for radio channel sounding purposes. Due to its slow channel sounding speed, it has been mainly used for channel measurements in static propagation scenarios. The main limitation with VNA based channel sounder is its small measurement range, due to signal attenuation in the coaxial cable setup. Employing radio over fiber (RoF) can effecti

A Novel Air-to-Ground Channel Modeling Method Based on Graph Model

Air-to-ground (A2G) communication is envisioned to support numerous applications in 5G wireless networks. In this paper, an active measurement campaign for unmanned aerial vehicle (UAV) channels is introduced. Simulation based on Graph Model (GM) is also conducted for this specific measurement. Both the measured and simulated channel impulse responses (CIRs) are extracted. Based on the CIRs, the m

Millimeter-Wave Channel Characterization in Large Hall Scenario at the 10 and 28 GHz Bands

This paper presents the characteristics of the mm-wave propagation channel in hall scenario at the frequency bands of 9-11 GHz and 27-29 GHz. The spherical propagation parameters, i.e. delay, azimuth, elevation, source distance and complex amplitude are estimated by the high resolution parameter estimation (HRPE) algorithm. Based on the results, the channel characteristics, e.g. path loss, delay s

An empirical air-to-ground channel model based on passive measurements in LTE

In this paper, a recently conducted measurement campaign for unmanned-aerial-vehicle channels is introduced. The downlink signals of an in-service long-time-evolution network, which is deployed in a suburban scenario were acquired. Five horizontal and five vertical flight routes were considered. The channel impulse responses (CIRs) are extracted from the received data by exploiting the cell-specif

Hough-transform-based cluster identification and modeling for V2V channels based on measurements

In this paper, a recently conducted measurement campaign for vehicle-to-vehicle (V2V) propagation channel characterization is introduced. Two vehicles carrying a transmitter and a receiver, respectively, have been driven along an eight-lane road with heavy traffic. The measurement was conducted with 100 MHz signal bandwidth at a carrier frequency of 5.9 GHz. Channels are observed consisting of two

Fading characterization of 73 GHz millimeter-wave V2V channel based on real measurements

In this work, a recently conducted measurement campaign for millimeter wave (mm-wave) vehicle to vehicle (V2V) propagation channel characterization is introduced. Two vehicles carrying a transmitter (Tx) and a receiver (Rx) respectively were driven towards each other at an average speed of 60 km/h in an urban area of Jiading District, Shanghai, China. The measurement was conducted with 409.6 MHz b

Air-to-Ground Big-Data-Assisted Channel Modeling Based on Passive Sounding in LTE Networks

In this paper, a novel approach of channel modeling based on big data analysis is proposed that is applied to extract air-to-ground channel models from down-link signals collected by using an Unmanned Aerial Vehicle (UAV) in operating Long-Term-Evolution (LTE) networks. In this approach, the most "sensitive" channel parameter to the UAV height is chosen based on a feature selection algorithm from

Experimental characterization of millimeter-wave indoor propagation channels at 28 GHz

The increasing requirement for the mobile data traffic accelerates the research of millimeter-wave (mm-wave) for future wireless systems. Accurate characterization of the mm-wave propagation channel is fundamental and essential for the system design and performance evaluation. In this paper, we conducted measurement campaigns in various indoor scenarios, including classroom, office, and hall scena

A Centralized and Scalable Uplink Power Control Algorithm in Low SINR Scenarios

Power control is becoming increasingly essential for the fifth-generation (5G) and beyond systems. An example use-case, among others, is the unmanned-aerial-vehicle (UAV) communications where the nearly line-of-sight (LoS) radio channels may result in very low signal-to-interference-plus-noise ratios (SINRs). The authors in (Chiang et al., 2007) proposed to efficiently and reliably solve this kind

A sea-wave-dynamics monitoring radar based on propagation characteristics of echo signals

As human's marine activities, such as marine aquaculture, ocean shipping and coastal facilities construction, flourished world-widely, it is required to monitor the sea-wave dynamics timely and accurately. The radar introduced in this paper, namely “Sea-wave-dynamics Monitoring and Imaging System (SMIS)”, working in the S-band at the center frequency of 3.1 GHz, is applicable to retrieving sea-wav

Affordable Quality of Service Assessment for Cellular-Connected UAV Communications

In recent years, Unmanned Aerial Vehicles (UAVs)have been used extensively in military and civilian fields, making the research on cellular-connected UAVs a popular topic forFifth Generation (5G) and beyond communications. In order to support the increasing amount of applications, it is essential to evaluate the performance of UAV communications. In this work, the end-to-end delay, packet success

Bounded Path-Loss Model for UAV-to-UAV Communications

In this paper, we focus on ultra-dense network modelingwhere both the Base Stations (BSs) and Mobile Terminals(MTs) are UAVs. In this case, two communication nodes canbe very close to each other. However, existing cellular networkanalyses typically use the standard unbounded path loss modelwhere received power decays like r^beta over a distance r. Thisstandard model is a good approximation for the

Characterizing the Small-Scale Fading for Low Altitude UAV Channels

In this contribution, a recently conducted measurement campaign in a suburban scenario for the Unmanned Aerial Vehicle (UAV) Air-to-Ground (A2G) radio channel is introduced.The downlink signals in an in-service Long Term Evolution (LTE) network were collected and utilized to extract the Channel Impulse Responses (CIRs). A high-resolution parameter estimation algorithm derived based on the Space-Al

A Complexity-Efficient High Resolution Propagation Parameter Estimation Algorithm for Ultra-Wideband Large-Scale Uniform Circular Array

Millimeter wave (mm-wave) communication with large-scale antenna array configuration is seen as the key enabler of the next generation communication systems. Accurate knowledge of the mm-wave propagation channels is fundamental and essential. In this contribution, a novel complexity-efficient high resolution parameter estimation (HRPE) algorithm is proposed for the mm-wave channel with large-scale

Diabetes Mellitus as a Risk Factor for Trigger Finger – a Longitudinal Cohort Study Over More Than 20 Years

Background and Aim: Trigger finger (TF) or stenosing tenosynovitis has been associated with diabetes mellitus (DM), although today’s knowledge is mostly based on cross-sectional and case-control studies. Thus, the aim of the present population-based cohort study over more than 20 years was to investigate DM as a risk factor for TF.Methods: Data from Malmö Diet and Cancer Study (MDCS), including 30