Exploiting chirp spread spectrum and error detection in LoRa collision recovery

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Abstract/Contents

Abstract
LoRa is a prominent radio technology for wide-area IoT applications. LoRa allows a gateway to receive packets from low-power transmitters over a range of miles. But when two transmissions collide, the gateway loses one or both of them. Collisions waste airtime and energy. This dissertation proposes two novel cross-layer techniques that enable LoRa receivers to successfully receive colliding packets with high probability. The first, called symbol querying, changes the interface between the LoRa demodulator and decoder. Symbol querying greatly improves the ability of a LoRa receiver to successfully receive the stronger frame in a collision. It does so by elevating the error detection capabilities of channel coding into error correction. For instance, a receiver using (8, 4)-extended Hamming codes can correct two, instead of only one, bit errors per codeword. The second technique, called symbol SIC, uses the unique discrete properties of LoRa symbols to enable the efficient reception of the weaker frame in a collision, by subtracting the stronger frame's peaks in the frequency domain. This dissertation presents a prototype LoRa receiver that includes symbol querying and symbol SIC using an inexpensive, off-the-shelf software-defined radio (SDR). When receiving colliding frames, this implementation receives up to 17x more frames than traditional LoRa receivers and symbol querying cuts the energy costs of communication by up to 4.6x compared to an SIC-only design.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2021; ©2021
Publication date 2021; 2021
Issuance monographic
Language English

Creators/Contributors

Author Jung, Raejoon
Degree supervisor Levis, Philip
Thesis advisor Levis, Philip
Thesis advisor Bambos, Nicholas
Thesis advisor Jamieson, Kyle
Degree committee member Bambos, Nicholas
Degree committee member Jamieson, Kyle
Associated with Stanford University, Department of Electrical Engineering

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Raejoon Jung.
Note Submitted to the Department of Electrical Engineering.
Thesis Thesis Ph.D. Stanford University 2021.
Location https://purl.stanford.edu/dp797rg4331

Access conditions

Copyright
© 2021 by Raejoon Jung
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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