In parallel with the decrease in cost, size and weight of Unmanned Aerial Vehicles (UAVs) and the increase of their flight autonomy, many commercial applications are rapidly arising. Most of those applications rely on a communications system between a terrestrial base station and the UAV. Due to the UAV movement, time-variant channel models are required. In this article, we propose a geometrical m

In a wireless communication system, the radio propagation channel is a complicated component to characterise. Channel sounding equipment thus has to meet specific criteria to extract the desired channel parameters. In this study, the authors outline the development and validation of a vector network analyser (VNA) based channel sounder for the frequency range from 1 to 50 GHz using radio-over-fibr

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

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

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

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 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

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

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

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

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

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

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

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

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

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

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

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

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

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