765 research outputs found
A LTE MIMO OTA Test System Using Vector Signal Transceivers
A 2 × 2 multiple-input-multiple-output over-the-air (MIMO OTA) test system based on four field-programmable Vector-Signal-Transceiver (VST) modules is presented. The system enables 2 x 2 MIMO OTA testing by assembling of a twochannel Evolved Node B (eNodeB) LTE base station emulator, a 2x2 channel emulator, and a two-channel user equipment (UE) simulator. A two-stage MIMO OTA test method has been demonstrated with downlink Long-Term Evolution Time-Division Duplex (LTE-TDD) mode using different modulation and coding schemes (MCSs). Test results and analysis are shown. This system will allow a systematic study of MIMO OTA metrology needs
A Software-Defined-Radio Platform for Multiple-Input-Multiple-Output Over-The-Air Measurement
This paper presents a 2 × 2 multiple-inputmultiple-output over-the-air (MIMO OTA) measurement system with user-programmable, reconfigurable and real-time signal processing field-programmable gate arrays (FPGAs)-based software-defined radio (SDR) capability. Signal generation and analysis as well as channel emulation are all implemented using vector signal transceivers (VSTs). As a demonstration, we performed the Third Generation Partnership Project (3GPP) two-stage MIMO OTA conducted test using a downlink time division long-term evolution (TD-LTE) duplex scheme. The channel emulation was operated in a stochastic mode. Some preliminary results of the system verification are shown
LTE Spectrum Sharing Research Testbed: Integrated Hardware, Software, Network and Data
This paper presents Virginia Tech's wireless testbed supporting research on
long-term evolution (LTE) signaling and radio frequency (RF) spectrum
coexistence. LTE is continuously refined and new features released. As the
communications contexts for LTE expand, new research problems arise and include
operation in harsh RF signaling environments and coexistence with other radios.
Our testbed provides an integrated research tool for investigating these and
other research problems; it allows analyzing the severity of the problem,
designing and rapidly prototyping solutions, and assessing them with
standard-compliant equipment and test procedures. The modular testbed
integrates general-purpose software-defined radio hardware, LTE-specific test
equipment, RF components, free open-source and commercial LTE software, a
configurable RF network and recorded radar waveform samples. It supports RF
channel emulated and over-the-air radiated modes. The testbed can be remotely
accessed and configured. An RF switching network allows for designing many
different experiments that can involve a variety of real and virtual radios
with support for multiple-input multiple-output (MIMO) antenna operation. We
present the testbed, the research it has enabled and some valuable lessons that
we learned and that may help designing, developing, and operating future
wireless testbeds.Comment: In Proceeding of the 10th ACM International Workshop on Wireless
Network Testbeds, Experimental Evaluation & Characterization (WiNTECH),
Snowbird, Utah, October 201
Beamforming in MISO Systems: Empirical Results and EVM-based Analysis
We present an analytical, simulation, and experimental-based study of
beamforming Multiple Input Single Output (MISO) systems. We analyze the
performance of beamforming MISO systems taking into account implementation
complexity and effects of imperfect channel estimate, delayed feedback, real
Radio Frequency (RF) hardware, and imperfect timing synchronization. Our
results show that efficient implementation of codebook-based beamforming MISO
systems with good performance is feasible in the presence of channel and
implementation-induced imperfections. As part of our study we develop a
framework for Average Error Vector Magnitude Squared (AEVMS)-based analysis of
beamforming MISO systems which facilitates comparison of analytical,
simulation, and experimental results on the same scale. In addition, AEVMS
allows fair comparison of experimental results obtained from different wireless
testbeds. We derive novel expressions for the AEVMS of beamforming MISO systems
and show how the AEVMS relates to important system characteristics like the
diversity gain, coding gain, and error floor.Comment: Submitted to IEEE Transactions on Wireless Communications, November
200
Laboratory measurement campaign of DVB-T signal with transmit delay diversity
The requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed cost-effectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of Transmit Delay Diversity (DD) with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using a SPIRENT SR5500 dual channel emulator. The relationship between correlation coefficient between channels, receiver velocity and diversity gain is nvestigated. It is shown that transmit delay diversity significantly improves the quality of reception particularly in simulated fast fading mobile broadcasting applications. This paper documents research conducted by Brunel University and Broadreach Systems
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Evaluation of diversity gains for DVB-T systems
Copyright @ 2008 Eurescom GmbHThe requirements for future DVB-T/H
networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed costeffectively
and with minimized environmental impact.
The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of transmit and
receive diversity gains with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using the Spirent dual channel emulator
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