LTE SYSTEM ARCHITECTURE FOR COVERAGE AND DOPPLER REDUCTION IN RANGE TELEMETRY

A novel approach employing 4G LTE Cellular Technology for Test Range Telemetry is presented. Providing aeronautical mobile telemetry using commercial off the shelf (COTS) cellular equipment poses many challenges, including: Three-dimensional (3D) coverage, need for uninterrupted high data throughputs, and very high Doppler speeds of the Test Articles (TA). Each of these requirements is difficult to meet with a standard cellular approach. We present a novel architecture that provides 3D coverage over the span of a test range, allowing the TA to establish a radio link with base stations that have a manageable Doppler due to the reduced projected TA speed on the radio link line. Preliminary results illustrate that a variety of flight plans can be accommodated with commercial LTE technology by employing LTE’s mobility mechanisms and adding centralized control. The resulting network architecture and Radio Access Network topology allow very high throughputs to be delivered throughout the test range with a judicious placement of base stations.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Instability and performance limits of distributed simulators of feedforward queueing networks

In this article we study the performance of distributed simulation of open feedforward queueing networks, by analyzing queueing models of message flows in distributed discrete event simulators. We view each logical process in a distributed simulation as comprising a message sequencer with associated message queues, followed aby an event processor. We introduce the idealized, but analytically useful, comcept of maximum lookahead. We show that, with quite general stochatstic assumptions for message arrival and time-stamp processes, the meassage queues are unstable for conservative sequencing, and for conservative sequencing with maximum lookahead and hence for optimistic resequencing, and for any resequenceing algorithm that does not employ interprocessor flow control. Finally, we provide formulas for the throughput of distributed simulators of feedforward queueing networks

RF Planning for 3D coverage in Cellular LTE Range Telemetry

Initial analysis and lab experiments have provided positive confirmation of the viability of 4G LTE Cellular Technology for Aeronautical mobile telemetry. COTS LTE equipment is deployed for the test range frequency bands. The high speeds of test articles (TAs) can be addressed with a UE add-on applique’ customized to compensate for the Doppler shifts. The applique has worked effectively with the LTE physical layer. To achieve spectrum efficiency, a multi-cell network is planned. Mobility is managed with native LTE handovers. To address extreme Doppler cases, additional support is provided to mobility management via a central entity that estimates the TA’s trajectory and issues handover commands. Within this framework, we present aspects of an RF planning study that characterizes the dependence of coverage on such design parameters as base station density, antenna orientation, and altitude of the user device. We also quantify the Doppler shifts that can result under the standard strategy of connecting the user device to the strongest cell, and show how, with an alternative, threshold-based strategy, one can achieve a substantial reduction in Doppler shifts at the expense of a loss in user rates.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

DOPPLER ESTIMATION AND COMPENSATION FOR LTE-BASED AERONAUTICAL MOBILE TELEMETRY

High Doppler shifts between base stations and test articles (TAs) pose the biggest problem to Aeronautical mobile telemetry (AMT) implemented on a wireless LTE network. Our solution to this problem includes a Doppler estimator/compensator (DEC) that proactively shifts the LTE uplink (LTE UL) signals transmitted by the TA. We have designed the DEC in the form of an applique’ that can be inserted between the transmit/receive ports of a COTS TA transceiver and its antenna(s). The DEC estimates the Doppler shift using the LTE UL signals transmitted by the TA, which carry a frequency offset that includes the Doppler shift. This not only provides a clean, noise- and fading-free signal for Doppler estimation, but also allows us to do away with the need to know the identity of the base station with which the TA is communicating. In this paper, we provide an architectural description of the DEC and an outline of the algorithms that have been incorporated into it. At present, a laboratory prototype of the DEC has been developed using Universal Software Radio Peripherals (USRPs), coupled with a Linux PC to carry out most of the computations. An FPGA-based implementation is currently under development.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Cellular 4G LTE Aeronautical Mobile Telemetry Flight Test Results

Flight test results on an Aeronautical Mobile Telemetry (AMT) system employing 4G Long Term Evolution (LTE) Cellular Technology are presented. The AMT system comprises a ground network of Commercial Off-The-Shelf (COTS) cellular base stations. Very high Doppler shifts due to the high speed of the Test Article (TA) are handled by an appliqué front-end to a COTS mobile transceiver. Doppler compensation allows seamless operation of LTE as the TA traverses the coverage area. An uninterrupted radio link as well as high bi-directional data rates were achieved even at a distance of 60 Km between the base stations and the TA. The results clearly demonstrate that the system can sustain an uninterrupted LTE connection at Doppler shifts that are much higher than what typical commercial LTE systems can support. The 4G system featured in this exercise has a direct extension to 5G technologies.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit https://telemetry.org/contact-us/ if you have questions about items in this collection

LTE-BASED AERONAUTICAL MOBILE TELEMETRY - LAB AND FIELD TEST EXPERIMENTS

Aeronautical mobile telemetry (AMT) based on 3GPP’s LTE standard is implemented in a proof-of-concept system. The solution tackles the very high Doppler shifts expected in flight tests using an appliqué that can be inserted between the transmit/receive ports of the Test Article (TA) and the antennas. This appliqué estimates the Doppler shift and proactively compensates for it on the uplink signal being transmitted by the TA. The overall system has been tested under different operational conditions in a laboratory setup as well as in the field. In the laboratory setup, the desired operating conditions are created with a set of Software-Defined-Radio-based channel emulators coupled with a computer to control their behavior. In order to carry out field tests, an operational LTE network has been created at Edwards Air Force Base (EAFB) with two base stations, backhaul links, and a core network. In this paper, we provide descriptions of both laboratory and field test setups as well as the results of several tests that have been carried out to date. The results of lab and field tests lend strong support to the viability of this AMT solution.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

5G Cellular-Based Telemetry Airborne Transceiver

A novel 5G-compliant airborne transceiver is being designed and developed to support 5G-cellular-based aeronautical mobile telemetry (AMT). To support operation at speeds likely to be encountered in airborne telemetry, the transceiver includes our Velocite solution for on-board Doppler pre-compensation and is designed to meet the 5G enhanced-Mobile-Broadband (eMBB) service objectives. This paper presents an overview of the airborne transceiver’s overall design approach which includes a commercial 5G mobile modem and a field-programmable gate array (FPGA)-based Doppler compensator. It also describes the planned capabilities of the transceiver, the ground network architecture needed to support cellular telemetry, and system-level operation aspects. Finally, the paper concludes with a description of the specific design aspects that need to be considered for AMT, including a ruggedized design for integration with the test airframe to support AMT at the testing range.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit https://telemetry.org/contact-us/ if you have questions about items in this collection

Effect of Drying Methods on Swelling, Erosion and Drug Release from Chitosan–Naproxen Sodium Complexes

The purpose of this research was to explore theapplication of ionic interactions between naproxen sodium (NS) and chitosan (CH) in complexes (NSC) prepared by tray drying (TD) and spray drying (SD) methods. Drug–polymer ratio (1:1) in the NSC was optimized on the basis of dialysis studies. The particulate systems of NSC were prepared by tray drying (TD) and spray drying (SD) methods. Release retarding polymers were added to the NSC and to the physical mixtures containing NS–CH and their effects on water uptake, matrix erosion and drug release at different pH were compared. Spray dried complexes (SDC) were spherical, free flowing, light and fine amorphous particles in contrast to the crystalline, hard, tenacious, irregularly shaped, denser tray dried complexes (TDC) with poor flowability. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) patterns confirm the conversion of crystalline to high energy amorphous phase suitable for ionic interactions in NSC. Presence of release retarding polymers, kappa carrageenan and hydroxypropylmethylcellulose (HPMC) in the NSC compacts retarded the drug release and improved the matrix integrity. Carrageenan matrices exhibited more retardation than HPMC tablets. FTIR patterns, erosion, swelling and drug release from matrices support ionic interactions between NS and CH in NSC. The reasons for retarded drug release from the chitosan matrices at acidic pH include poor solubility of drug at acidic pH, formation of a rate limiting polymer gel barrier along the periphery of matrices and the ionic interactions between oppositely charged moieties