Use of backscatter signals for positioning within wireless networks

A method comprising:

• controlling receiving, by a user device, frequency-shifted signals from a plurality of backscatter nodes for locating the user device, wherein each of the plurality of backscatter nodes is identifiable by a backscatter node-specific frequency offset of the frequency-shifted signals according to a configuration;
• determining, by the user device, phase information and a frequency offset for each of the received frequency-shifted signals;
• and
• controlling transmitting, by the user device to a network node that provides the configuration:
• the phase information and the frequency offset for each of the received frequency-shifted signals, for a positioning control entity to carry out the locating of the user device based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the positioning control entity;
• or
• a location of the user device that is determined, by the user device, based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the user device.

An apparatus comprising:

• at least one processor;
• and
• at least one memory including computer program code;
• the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:
• control receiving, by a user device, frequency-shifted signals from a plurality of backscatter nodes for locating the user device, wherein each of the plurality of backscatter nodes is identifiable by a backscatter node-specific frequency offset of the frequency-shifted signals according to a configuration;
• determine, by the user device, phase information and a frequency offset for each of the received frequency-shifted signals;
• and
• control transmitting, by the user device to a network node that provides the configuration:
• the phase information and the frequency offset for each of the received frequency-shifted signals, for a positioning control entity to carry out the locating of the user device based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the positioning control entity;
• or
• a location of the user device that is determined, by the user device, based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the user device.

An apparatus comprising at least one processor;

• and
• at least one memory including computer program code;
• the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to;
• control transmitting, by a network node to a plurality of backscatter nodes, the locations of which are known, configuration information comprising backscatter node-specific frequency offsets for the plurality of backscatter nodes, wherein each of the backscatter nodes is identifiable by a backscatter node-specific frequency offset;
• control receiving, by the network node from a positioning control entity, a location request for one or more user devices;
• control transmitting, by the network node, a signal to at least some of the plurality of backscatter nodes for the signal to be frequency shifted by a backscatter node-frequency offset according to the configuration information and transmitted by the at least some of the plurality of backscatter nodes to one or more user devices;
• and
• control receiving, by the network node from a user device:
• the phase information and the frequency offset for each of the received frequency-shifted signals, for a positioning control entity to carry out the locating of the user device based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the positioning control entity;
• or
• a location of the user device that is determined, by the user device, based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the user device;
• controlling transmitting, by the network node to the positioning control entity, at least one of the following:
• the phase information and the frequency offset, received by the network node and determined by the user device, for each of the plurality of received frequency-shifted signals;
• or
• the location of the user device, received by the network node and determined by the user device based on the phase information and frequency offset of the plurality of received backscatter signals and locations of the backscatter nodes known by the user device.