The present disclosure describes the system and methods for providing broadband internet access to homes and enterprises using a network of aerial platforms such as drones/UAVs/balloons. The drone communication system is composed of an antenna sub-system, a radio sub-system and a data switching sub-system. Drones form and point beams toward ground terminals in different areas in a space division multiple access scheme. Ground terminals are composed of an antenna sub-system and a radio sub-system. Ground terminals search for the drone from which they receive the strongest signals. Drone and ground terminals comprise of methods and systems to calibrate receive and transmit antenna elements. Drone radio sub-system keeps track of the drone's position and orientation changes and adjust drone's antenna beam accordingly to point to the same location on the ground as the drone moves. Depending on the changes in drone's position and orientation, the drone radio sub-system may switch the antenna aperture and/or the antenna fixture that is used to form a beam toward a specific ground terminal. Drones communicate with the terminals using a space and time division multiple access scheme.

Provided is a node unit which is branch-connected to another communication node via a transport medium, the node unit comprising: a delay measurement unit which transmits a test signal for measuring a delay to an adjacent node unit of the branch-connected upper stage via the transport medium and detects a loopback signal to which the test signal is looped back via the adjacent node unit of the upper stage, thereby measuring an upper stage transmission delay between the adjacent node unit of the upper stage and the node unit; a delay summation unit which, when an adjacent node unit of the branch-connected lower stage exists, receives a lower stage transmission delay transmitted from the adjacent node unit of the lower stage, and calculates a summed transmission delay by summing the upper stage transmission delay and the lower stage transmission delay; and a control unit which transmits the summed transmission delay to the adjacent node unit of the upper stage.

Methods, systems, and devices for wireless communications are described. The method includes receiving, from a base station, control signaling identifying a measurement configuration for one or more non-linear estimation measurements of reference signals associated with a power amplifier configuration of the base station, receiving, from the base station, the reference signals on a set of resources identified by the measurement configuration, performing one or more non-linear estimation measurements associated with the power amplifier configuration of the base station based on the received reference signals, and transmitting, to the base station according to the measurement configuration, a measurement report based on the one or more non-linear estimation measurements.

A system and method for testing (e.g., rapidly and inexpensively) devices such as integrated circuits (IC) with integrated antennas configured for millimeter wave transmission and/or reception. The method may first perform a calibration operation on a reference device under test (DUT). The calibration operation may determine a set of reference DUT FF base functions and may also generate a set of calibration coefficients. After the calibration step using the reference DUT, the resulting reference DUT FF base functions and the calibration coefficients (or reconstruction matrix) may be used in determining far-field patterns of DUTs based on other field measurements, e.g., measurements taken in the near field of the DUT.

Various embodiments disclosed herein provide for a low complexity transmitter structure for active antenna arrays by reducing the number of digital predistortion extraction loops that need to be performed. Digital predistortion (DPD) corrects any non-linearities in a power amplifier. By determining which power amplifiers have similar characteristics in an array, and thus may use similar predistortion coefficients, once the DPD coefficients are determine for one of the grouped power amplifiers, DPD can be performed on each of the grouped power amplifiers based on the DPD coefficients.

An object is to enable high-accuracy position estimation of a wireless terminal station by efficiently performing connection between a wireless base station and the wireless terminal station using multiple distributed antennas. A position estimation apparatus configured to estimate a position of a wireless terminal station between a wireless base station that can perform transmission and reception by switching between a plurality of distributed antennas arranged in a distributed manner via cables with known lengths, and the wireless terminal station configured to communicate with the wireless base station, includes: a means 1 for measuring a no-delay RTT or measuring a statistical processing RTT when the wireless base station exchanges a measurement signal and a response signal with the wireless terminal station in each of the distributed antennas and measures an RTT, which is a round trip time between the wireless base station and the wireless terminal station, a delay time having been removed from the no-delay RTT using a reception time of the measurement signal and a transmission time of the response signal, and the statistical processing RTT being measured using statistical processing for making the delay time constant using a plurality of instances of exchanging a measurement signal and a response signal; and means 2 for estimating the position of the wireless terminal station based on the no-delay RTT or the statistical processing RTT of each of the distributed antennas.

Components, systems, and methods for determining propagation delay of communications in distributed antenna systems are disclosed. The propagation delay of communications signals distributed in the distributed antenna systems is determined. If desired, the propagation delay(s) can be determined on a per remote antenna unit basis for the distributed antenna systems. The propagation delay(s) can provided by the distributed antenna systems to a network or other system to be taken into consideration for communications services or operations that are based on communications signal delay. As another non-limiting example, propagation delay can be determined and controlled for each remote antenna unit to uniquely distinguish the remote antenna units. In this manner, the location of a client device communicating with a remote antenna unit can be determined within the communication range of the remote antenna unit.

The described technology is generally directed towards multidimensional grid sampling for radio frequency power feedback. A mobile device can sample radio frequency signal power at multiple sample points, and can send sample values to a base station. The multiple sample points can be defined with reference to a grid having a first dimension and a second dimension, such as time and frequency, or delay and Doppler. A variety of techniques are provided to define the multiple sample points.

Technologies for determining the parameters of a transmission line such as a printed circuit board trace and a cable are disclosed. By measuring a reflection coefficient and a transmission coefficient of two different electrical structures with the same type of fixture on each end and transmission lines of different lengths, the attenuation coefficient of the transmission lines can be determined. The attenuation coefficient can indicate whether or not the performance of the transmission line is acceptable or may be used to calibrate a measuring device for subsequent measurements.

A method for measuring intermodulation produced in a measurement segment of a signal transmission path, by: producing a first. HF signal (u.sub.1(t)) and a second HF signal (u.sub.2(t)), both having a predetermined frequency progression; feeding the first HF signal (u.sub.1(t)) and the second HF signal (u.sub.2(t)) to the signal transmission path, wherein an intermodulation signal is produced, which intermodulation signal has a first intermodulation signal component (u.sub.rPIM(t)) produced in an input segment of the signal transmission path and a second intermodulation signal component (u.sub.PIM(t)) produced in the measurement segment of the signal transmission path; producing a compensation signal (u.sub.c(t)) in accordance with the first intermodulation signal component (u.sub.rPIM(t)) produced in the input segment; introducing the compensation signal (u.sub.c(t)) into the signal transmission path in order to reduce or cancel out the first intermodulation signal component (u.sub.rPIM(t)). The invention further relates to a measuring device for performing said method.