US 12,228,631 B1
Multistatic backscatter for joint communication and ranging
Ioannis Kimionis, Murray Hill, NJ (US); Michael Eggleston, Columbus, OH (US); Eleftherios Kampianakis, Murray Hill, NJ (US); and Traian Abrudan, Espoo (FI)
Assigned to Nokia Solutions and Networks Oy, Espoo (FI)
Filed by Nokia Solutions and Networks Oy, Espoo (FI)
Filed on Aug. 1, 2024, as Appl. No. 18/791,959.
Claims priority of application No. 20235886 (FI), filed on Aug. 9, 2023.
Int. Cl. G01S 13/00 (2006.01); G01S 13/36 (2006.01)
CPC G01S 13/003 (2013.01) [G01S 13/36 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A multistatic backscatter system comprising
at least one transmitter device to transmit carrier signals over a frequency set of two or more different frequencies;
at least one backscatter device configured to frequency-shift the carrier signals, modulate data on at least some of the carrier signals, and backscatter modulated frequency-shifted carrier signals as backscatter signals; and
at least one receiver device configured at least to receive the carrier signals and the backscatter signals, split the signals received at least to a first sub-signal and a second sub-signal, sub-channelize at least the first and second sub-signals to two or more carrier sub-channels and two or more back-scatter sub-channels to obtain at least one set of two pairs comprising a pair of carrier sub-channels and a pair of corresponding backscatter sub-channels, determine, per a set of two pairs, an occurrence time interval of an occurrence of a backscatter signal in a backscatter sub-channel, demodulate the backscatter sub-channel during the occurrence time interval to obtain the data, determine from the data at least identifier of a backscatter device, and determine, based at least on the occurrence time interval, ranging information for the backscatter device, by determining a reference carrier phase per a carrier sub-channel in the pair of carrier sub-channels during the occurrence time interval, estimating a modulated backscatter signal phase per a backscatter sub-channel in the pair of corresponding backscatter sub-channels during the occurrence time interval, calculating a normalized ranging differential phase using reference carrier phases and modulated backscatter signal phases, and calculating a distance estimate for the backscatter device using the normalized ranging differential phase, wherein the distance estimate is the ranging information,
wherein the at least one transmitter device, the at least one backscatter device and the at least one receiver device are unsynchronized.