US 9,813,877 B1
Accurate indoor positioning with cellular signals
Rabih Chrabieh, Paris (FR)
Assigned to Nestwave SAS, Paris (FR)
Filed by Rabih Chrabieh, Paris (FR)
Filed on Dec. 14, 2015, as Appl. No. 14/968,880.
Int. Cl. H04W 4/04 (2009.01); H04W 56/00 (2009.01); H04W 64/00 (2009.01)
CPC H04W 4/043 (2013.01) [H04W 56/001 (2013.01); H04W 64/00 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A positioning system configured for being used in conjunction with a server and a communication device synchronized with a cellular network, the positioning system comprising:
a plurality of positioning cells, each positioning cell comprising an antenna unit configured for emitting and receiving radio-frequency signals, and being associated with a non-volatile memory unit configured for storing data, a processing unit configured for processing data and for controlling an operation of the antenna unit, and a power source configured for powering the antenna unit;
wherein, at least one of the positioning cells is connected to a cellular network, and the positioning cells are configured for emitting respective positioning signals receivable by the communication device in a frequency used by the cellular network, in response to the reception of a synchronization signal emitted by the cellular network, each positioning signal comprising data indicative of an identifier of the positioning cell that emitted the positioning signal;
wherein the positioning cells are configured for transmitting the positioning signals in at least one of the following spectra:
a spectrum of a given operator in the cellular network;
a spectrum of a plurality of operators in the cellular network; and
an unlicensed spectrum not associated with any operator in the cellular network;
wherein the positioning cells are set in groups;
the positioning cells belonging to any same group are configured for emitting the respective positioning signals at the same time;
each group of positioning cells is configured for emitting the respective positioning signals in quick succession at respective times following the synchronization signal;
at least one first positioning cell of any given group is configured for listening to at least one second positioning signal emitted by at least one second positioning cell;
the at least one first positioning cell is configured for determining a time difference between the time of arrival of the second positioning signal at the first positioning cell and a respective theoretical time of arrival that would occur if the at least one second positioning cell were synchronized with the at least one first positioning cell;
the at least one first positioning cell is configured for transmitting data indicative of the difference to the at least one second positioning cell by wire or wirelessly;
the at least one second positioning cell is configured to adjust a timing of emission of the second positioning signal according to the difference, in order to synchronize with the at least one first positioning cell; and
wherein the server is in communication with the communication device, the server being configured for:
receiving from the communication device first data indicative of times of arrival of the positioning signals to the communication device, each piece of data indicative of a time of arrival being appended with an identifier of the associated positioning cell;
processing the times of arrival and using known positions of the positioning cells to determine a position of communication device with respect to the positioning cells; and
sending to the communication device second data indicative of the position.