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The challenges associated with efficiently and effectively linearizing a nonlinear power amplifier (PA) over wide signal bandwidths are increasingly important to the design of 5G front-ends. Conventional digital linearization techniques are limited by absolute bandwidth, while the RF-domain nonlinear PA typically exhibits consistent fractional bandwidth even as the carrier frequency is increased. Therefore, RF-domain design techniques, like those focusing on bias-line impedance selection, are critical for overall distortion reduction. To evaluate bias-line effects, a demonstrator PA is here investigated over a range of Class-AB biases and over a range of drain inductance values. The characterization under two-tone and LTE-like modulated excitations with 10-MHz and 100-MHz instantaneous bandwidth shows that the conventional linear-efficiency trade-off in bias design does not necessarily hold true for wide instantaneous bandwidths. Additionally, techniques to synthesize a negative baseband impedance using low frequency feedback are discussed.
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Enabling IoT Self-Localization Using Ambient 5G Signals
This paper presents ISLA, a system that enables low power IoT nodes to self-localize using ambient 5G signals without any coordination with the base stations. ISLA operates by simply overhearing transmitted 5G packets and leverages the large bandwidth used in 5G to compute high-resolution time of flight of the signals. Capturing large 5G bandwidth consumes a lot of power. To address this, ISLA leverages recent advances in MEMS acoustic resonators to design a RF filter that can stretch the effective localization bandwidth to 100 MHz while using 6.25 MHz receivers, improving ranging resolution by 16x. We implement and evaluate ISLA in three large outdoors testbeds and show high localization accuracy that is comparable with having the full 100 MHz bandwidth.
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- PAR ID:
- 10325031
- Date Published:
- Journal Name:
- 19th USENIX Symposium on Networked Systems Design and Implementation (NSDI 22)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
