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One of the challenges in direct conversion Doppler radar lies in the dc offset resulted from antenna coupling. The dc offset may saturate the baseband amplifiers, preventing sufficient amplification of the received signal. In this work, a Coupling-Cancellation-Antenna (CCA) was implemented in the radar front end to enhance radar detection accuracy by minimizing the TX-RX antenna coupling. The idea is to have two transmitting antennas fed by signals with 180° phase difference such that the two signals cancel at the RX antenna. As a result, a larger receiver gain can be used to improve the signal to noise ratio without saturating the baseband output. Experimental validations of the CCA concept demonstrate 37-dB reduction in the TX-RX coupling. Furthermore, the CCA method reduces the detection error from 15.8% to 2.4%.
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A Link Between Multiuser MMSE and Canonical Correlation Analysis
Recent work has shown that repetition coding followed by interleaving induces signal structure that can be exploited to separate multiple co-channel user transmissions, without need for pilots or coordination/synchronization between the users. This is accomplished via a statistical learning technique known as canonical correlation analysis (CCA), which works even when the channels are time-varying. Previous analysis has established that it is possible to identify the user signals up to complex scaling in the noiseless case. This letter goes one important step further to show that CCA in fact yields the linear MMSE estimate of the user signals up to complex scaling, without using any explicit training. Instead, CCA relies only on the repetition and interleaving structure. This is particularly appealing in asynchronous ad-hoc and unlicensed setups, where tight user coordination is not practical.
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- Award ID(s):
- 2118002
- PAR ID:
- 10516585
- Editor(s):
- NA
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Wireless Communications Letters
- Edition / Version:
- 1
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2162-2337
- Page Range / eLocation ID:
- 44 to 48
- Subject(s) / Keyword(s):
- Multiuser interference, canonical correlation analysis (CCA), repetition coding, minimum mean square error (MMSE) estimation
- Format(s):
- Medium: X Size: 132KB Other: .pdf
- Size(s):
- 132KB
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1109/LWC.2023.3319292
