622 research outputs found
Wideband Self-Adaptive RF Cancellation Circuit for Full-Duplex Radio: Operating Principle and Measurements
This paper presents a novel RF circuit architecture for self-interference
cancellation in inband full-duplex radio transceivers. The developed canceller
is able to provide wideband cancellation with waveform bandwidths in the order
of 100 MHz or beyond and contains also self-adaptive or self-healing features
enabling automatic tracking of time-varying self-interference channel
characteristics. In addition to architecture and operating principle
descriptions, we also provide actual RF measurements at 2.4 GHz ISM band
demonstrating the achievable cancellation levels with different bandwidths and
when operating in different antenna configurations and under low-cost highly
nonlinear power amplifier. In a very challenging example with a 100 MHz
waveform bandwidth, around 41 dB total cancellation is obtained while the
corresponding cancellation figure is close to 60 dB with the more conventional
20 MHz carrier bandwidth. Also, efficient tracking in time-varying reflection
scenarios is demonstrated.Comment: 7 pages, to be presented in 2015 IEEE 81st Vehicular Technology
Conferenc
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
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