Semtech Corporation

Christophe Jean Jacques Devaucelle

Olivier Bernard André Seller

An extension of the LoRa modulation with an improved ranging mode. A master and a slave device exchange a request and a reply that contain sequences of chirps that are carefully aligned in time, frequency, and preferably also phase, such that the master device can ascertain the propagation delay to the slave by demodulating the reply. Request and reply include chirps having different slopes, preferably slopes of equal absolute value and opposite sign. The slope diversity permits an unbiased estimation of the Doppler shift.

Doppler ranging system

A LoRa transmitter and corresponding receiver where the detection sequence in the preamble is phase-modulated and includes an information that encodes the position in the preamble, such as a countdown index. Nodes that wake up to receive a scheduled download can determine from this information how far the end of the detection sequence is and manage their energy consumption accordingly. The phase modulation is compatible with legacy devices.

Transmitter, receiver, and method for chirp-modulated radio signals

Transmitter for chirp-modulated radio signals comprising a chirp generator configured to generate a series of chirp signals, wherein each chirp carries an element of information encoded as a cyclic shift, and has a phase encoding an error correction code dependent form the cyclic shift of the chirp, the transmitter further comprising a modulator configured to modulate the series of chirp onto a radio signal and a radio transmitter, transmitting the radio signal. receiver for chirp-modulated radio signals, comprising a clock unit and a demodulator configured for demodulating a series of received chirps signal, the demodulator having a dechirp unit, configured for determining a cyclic shift of each received chirp relative to a base chirp and an error correction code based on a phase of the received chirp, the receiver having a synchronism correction unit configured to detect and/or correct an error in the clock unit based on the error correction code.

A LoRa receiver for processing digital chirp spread-spectrum modulated signals with an advanced module for the determination of the timing error and/or of the frequency error arranged to estimate a position of a frequency discontinuity in each symbol, extract one or more frequency-continuous fragments out of each symbol, dechirp the coherent fragments, determine a timing error, and/or a frequency error, and/or a modulation value, and/or a SNR.

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Boudevilliers, Switzerland

Christophe Jean Jacques Devaucelle