This paper examines the antenna diversity configurations that improve performance in handheld radios. Experiments using spatial, polarization, and pattern were conducted for both line-of-sight (LOS) obstructed outdoor indoor multipath channels experienced Ricean fading. Antenna separation, varied independently to extent possible. Envelope correlation, power imbalance, gain calculated from measurements. Diversity is measured by gain, which difference signal-to-noise ratio (SNR) between output...

A promising way of realizing the fifth generation (5G) wireless systems is to operate 5G deployments at higher frequency bands, specifically in millimeter-wave (mmW) spectrum (30-300 GHz). Access such bands will enable future meet requirements peak rate greater than 10 Gb/s, and cell edge up 1 Gb/s. However, emerging need coexist with a number incumbent these bands. This paper provides an extensive study co-channel coexistence two critical mmW 27.5-28.35 GHz (28 GHz) 71-76 (70 where fixed...

The 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> Generation Partnership Project released the cellular vehicular-to-everything (C-V2X) specifications as part of LTE framework in Release 14. C-V2X is alternative to dedicated short range communications and both are specifically designed for V2X control signaling. extends device-to-de-vice by adding two more modes operation targeting vehicular environment coverage out base stations....

Near-ground radio-wave propagation is of interest for emerging military applications such as battlefield sensor networks and wireless communication between dismounted soldiers. Narrowband wideband channel measurement results at 300 1900 MHz are presented near-ground propagation, characterising the effect antenna heights, radiation patterns foliage environments. An additional set measurements was performed to study rain on in a forest environment. Measured power–delay profiles indicate...

Recent advancements in radio technology provide great flexibility and enhanced capabilities executing wireless services. One of these that can significant advantages over traditional approaches is the concept collaborative computing networks. With nodes, multiple independent nodes operate together to form a distributed (WDC) network with significantly increased performance, operating efficiency, abilities single node. WDC exploits connectivity share processing- intensive tasks among devices....

We review diversity and smart antenna research applied to both base-stations terminals. To illustrate the performance gains possible, paper describes being conducted by Smart Antenna Group at Virginia Tech, in handheld

This article describes the Open Source SCA Implementation::Embedded project, an open source software development kit designed for rapid prototyping of defined radios consistent with Software Communications Architecture. The is a product American military's SDR acquisition program and has played large role in military wireless industry. OSSIE was use communications curricula research efforts, so it easy to learn illustrative engineering, programming, engineering concepts important industrial...

Software-defined radio is a rapidly developing field that driving the development of and innovation in communications technology, promises to significantly impact all sectors. Entities these SDR systems require trained workforce has been prepared with mindset, knowledge, skills, tools required address both system (breadth) technical (depth) aspects systems. Developing SDRs necessarily involves collection disciplines including, but not limited to, electromagnetics, radio-frequency...

This paper presents a pioneering study based on series of experiments the operation commercial Time-Division Long-Term Evolution (TD-LTE) systems in presence pulsed interfering signals 3550-3650 MHz band. TD-LTE operations were carried out channels overlapping and adjacent to high power SPN-43 radar with various frequency offsets between two evaluate susceptibility LTE signal. Our results demonstrate that communication using low antenna heights was not adversely affected by signal operating...

As 5G communication technology develops, vehicular communications that require high reliability, low latency, and massive connectivity are drawing increasing interest from those in academia industry. Due to these developing technologies, is not limited vehicle components the forms of Vehicle-to-Vehicle (V2V) or Vehicle-to-Infrastructure (V2I) networks, but has also been extended connect with others, such as pedestrians cellular users. Dedicated Short-Range Communications (DSRC) conventional...

Wideband measurements were performed using a direct-sequence spread-spectrum measurement system in the air-to-ground radio environment to characterize propagation between an airborne transmitter and ground-based receiving antenna array at center frequency of 2.05 GHz. The was flown along constant-radius arcs low altitudes around receiver location obtain results for 7.5, 15, 22.5, 30 degree elevation angles. An 80 megachip per second (Mcps) modulating PN sequence transmitted by station....

The Software Communications Architecture is an open architecture developed by the U.S. Department of Defense to standardize development software-defined radio, improve communication systems interoperability, and reduce deployment costs. SCA facilitates software reuse technology insertion abstracting radio applications from supporting platform defining a common operational environment across platforms. relies on commercial standards, classic engineering principles, design patterns. While some...

With the smaller physical scale of distributing radio frequency signal in buildings, distributed antenna systems, which may be too expensive outdoor become affordable. This paper explores quantitatively and qualitatively advantages systems over single point source develops theorems comparing two based on a slope path loss model.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An analytical expression for the probability density function of signal-to-noise ratio (SNR) at output a two-branch maximal and selection diversity system is given. The two branches are assumed to be Rayleigh fading, correlated, as well unequal average SNRs. Measurements cumulative distribution functions after combining were made in fading channels compared with results. Also presented exact probabilities symbol error coherent binary phase-shift keying quaternary before slow flat correlated channel.

Telecommunication industries and spectrum regulation authorities are increasingly interested in unlocking the 12 GHz band for two-way 5G terrestrial services. The has a much larger bandwidth than current sub-6 better propagation characteristics millimeter-wave (mmWave) band. Thus, offers great potential improving coverage capacity of networks. However, interference issues between incumbent receivers radio links present major challenge If one could exploit dynamic contexts inherent to band,...

Decentralized vehicle-to-everything (V2X) networks (i.e., Mode-4 C-V2X and Mode 2a NR-V2X), rely on periodic Basic Safety Messages (BSMs) to disseminate time-sensitive information (e.g., vehicle position) has the potential improve on-road safety. For BSM scheduling, decentralized V2X utilize sensing-based semi-persistent scheduling (SPS), where vehicles sense radio resources select suitable for transmissions at prespecified intervals termed as Resource Reservation Interval (RRI). In this...

Coexistence between radar and outdoor wireless fidelity (Wi-Fi) needs thorough study since the IEEE 802.11 working group (WG) opposed latest rules in 3550-3700 MHz (the 3.5 GHz band) that require “exclusion zones.” This letter proposes a method suppresses Wi-Fi-to-radar (WtR) interference, which Wi-Fi transmitter (TX) is selected to avoid beam angles toward victim radar. It distinguished from prior schemes it ensures remains operable while suppressing WtR interference.

Despite the rapid development of wireless technology, there has been little application technology to improve railroad crossing safety. We present vehicle-to-railroad channel characterization and dedicated short range communications (DSRC) performance results at crossings in rural suburban environments. Our show that an omnidirectional antenna provides slightly better conditions. However, a bi-directional increased warning by more than 200 m A proper configuration DSRC radio reliable...

This paper proposes Precoded SUbcarrier Nulling (PSUN), an orthogonal frequency-division multiplexing (OFDM) transmission strategy for a wireless communications system that needs to coexist with federal military radars generating pulsed signals in the 3.5 GHz band. considers existence of Environmental Sensing Capability (ESC), sensing functionality band coexistence architecture, which is one latest suggestions among stakeholders discussing Hence, this impacts imperfect precise analysis....

Modern web technology enables the 3D portrayal of real-time data. WebSocket connections provide data over without time-consuming overhead HTTP requests. The server-side "push" paradigm is particularly useful for creating novel tools such as CORNET3D, where visualization required. CORNET3D an innovative Web3D interface to a research and education test bed Dynamic Spectrum Access (DSA). Our system can drive several 2D portrayals spectral radio performance metrics from live, online system....

Virginia Tech is involved in both smart base station and terminal antenna research for wireless applications. Smart features vary from simple diversity combining to adaptive algorithm implementations. Measurement campaigns are described results presented.

This paper extends the previous proposition of Precoded Subcarrier Nulling (PSUN), a novel orthogonal frequency division multiplexing (OFDM) transmission scheme for operation in 3.5 GHz Band, to consideration imperfect sensing radar pulse parameters. We take into existence Environmental Sensing Capability (ESC), functionality Band coexistence architecture. provide an analysis framework where variables representing impacts on OFDM system are generalized. The demonstrates errors by ESC and...