Multistatic backscatter for joint communication and ranging

A receiver device comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the receiver device at least to:

• receive signals comprising at least carrier signals and corresponding backscatter signals, which are frequency-shifted, modulated backscattered carrier 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 pairs, an occurrence time interval of an occurrence of backscatter signal in a backscatter sub-channel;
• demodulate the backscatter sub-channel during the occurrence time interval to obtain data modulated to a backscatter signal;
• determine from the data obtained by demodulating at least an identifier of a backscatter device;
• and
• determine, during 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.

A method comprising at least:

• receiving signals comprising at least carrier signals and corresponding backscatter signals, which are frequency-shifted, modulated backscattered carrier signals;
• splitting the signals received at least to a first sub-signal and a second sub-signal;
• sub-channelizing 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;
• determining, per a set of pairs, an occurrence time interval of an occurrence of backscatter signal in a backscatter sub-channel;
• demodulating the backscatter sub-channel during the occurrence time interval to obtain data modulated to a backscatter signal;
• determining from the data obtained by demodulating at least an identifier of a backscatter device;
• and
• determining, during 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.