System and method of occupancy estimation utilizing transmitted signals

Abstract

A method estimating number of occupants in a region includes receiving at one or more receiving unit a signal or signals transmitted from one or more transmitting units, wherein the transmitting units are not associated with the one or more occupants located in the region. In addition, the method includes measuring one or more attributes of the received signal for a duration of time and calculating an occupancy estimate based, at least in part, on the measured attribute of the received signal.

1 . A method of detecting presence or absence of occupants within a structure/building, the method comprising:
 measuring at one or more units equipped with RF receivers one or more attributes of a radio-frequency (RF) signal generated by one or more transmitters located within the structure/building;   detecting a presence/absence of occupants in the region based, at least in part, on the measured attributes of the RF signal received at the one or more units; and   providing the detected presence/absence of occupants as an input to control systems associated with the structure/building.   
     
     
         2 . The method of  claim 1 , wherein the RF signal generated by the one or more transmitters is a non-information-carrying RF signal. 
     
     
         3 . The method of  claim 1 , wherein the RF signal is one or more of a WiFi, Bluetooth, or cellular signal. 
     
     
         4 . The method of  claim 1 , wherein the one or more attribute of the RF signal includes at least one of received signal strength, received signal strength indicator (RSSI), signal-to-noise ratio (SNR), received channel power indicator (RCPI), received signal phase, or Channel State Information (CSI). 
     
     
         5 . The method of  claim 1 , wherein the control systems include one or more of security systems, lighting systems, heating systems, cooling systems, and/or business planning/resource allocation system. 
     
     
         6 . The method of  claim 1 , wherein the one or more units equipped with RF receivers is included as part of a wireless-enabled thermostat, a wireless-equipped lighting fixture/system, a wireless-equipped HVAC system, or a smart home security system. 
     
     
         7 . The method of  claim 1 , wherein the one or more transmitters are included in the one or more units equipped with an RF receiver, wherein the one or more units are included as part of a wireless-enabled thermostat, a wireless-equipped lighting fixture/system, a wireless-equipped HVAC system, or a smart home security system. 
     
     
         8 . The method of  claim 1 , wherein detecting the presence/absence of occupants in the region utilizes a relationship that relates measured attributes of the received signal and the presence/absence of occupants to one another, wherein the relationship is a theoretical model, a heuristic relationship, a relationship developed from past measurements and learning, or a relationship developed from simulations. 
     
     
         9 . The method of  claim 8 , wherein the relationship utilizes a statistical or probabilistic function, a probability distribution function, a probability mass function, a correlation function, or a covariance function. 
     
     
         10 . The method of  claim 1 , wherein the presence/absence of occupants is detected based at least in part on the analysis of the line-of-sight (LOS) blocking/crossing of the received RF signal, or analysis of multi-path (MP) scattering/fading effect of the received RF signal, or analysis of both LOS blocking/crossing and MP scattering/fading. 
     
     
         11 . The method of  claim 1 , wherein the one or more units equipped with RF receivers is co-located with one or more of the transmitters. 
     
     
         12 . An occupancy detection system utilized a building, the occupancy detection system comprising:
 at least one receiving unit that includes an antenna for receiving a radio frequency (RF) signal;   at least one signal measurement unit that measures one or more attributes associated with the received RF signal; and   a processor configured to receive the one or more measured attributes associated with the received RF signal and to detect based on the measured attributes the presence or absence of occupants in a region, wherein the processor provides an output to one or more control systems that indicates whether occupants were detected within a given region of the building.   
     
     
         13 . The occupant detection system of  claim 12 , further including at least one wireless RF transmitting unit. 
     
     
         14 . The occupant detection system of  claim 12 , wherein the signal measurements unit measures one or more attributes associated with the received RF signal at a number of time instants, at a number of frequency instants, or at a number of time instants and a number of frequency instants. 
     
     
         15 . The occupant detection system of  claim 12 , wherein detecting the presence/absence of occupants in the region utilizes a relationship that relates measured attributes of the received RF signal and the presence/absence of occupants to one another, wherein the relationship is a theoretical model, a heuristic relationship, a relationship developed from past measurements and learning, or a relationship developed from simulations. 
     
     
         16 . The occupant detection system of  claim 15 , wherein the relationship utilizes a statistical or probabilistic function, a probability distribution function, a probability mass function, a correlation function, or a covariance function. 
     
     
         17 . The occupant detection system of  claim 12 , further including at least one transmitter unit that is co-located with the at least one receiving unit. 
     
     
         18 . The occupant detection system of  claim 12 , wherein the one or more control systems includes one or more of security systems, lighting systems, heating systems, cooling systems, and/or business planning/resource allocation system. 
     
     
         19 . A machine-readable storage medium having stored thereon a computer program for detecting occupancy within a region based on a radio frequency (RF) signal transmitted from one or more transmitter units to one or more receiver units that measures one or more signal attributes of the received RF signal, the computer program comprising a routine of set instructions for causing the processor executing the instructions to perform the steps of:
 generating a function representative of the measured signal attribute; and   detecting the presence/absence of occupants in the region based, at least in part, on the measured attributes of the received signal and a relationship that relates measured attributes and occupancy to one another, wherein the relationship is a theoretical model, a heuristic relationship, a relationship developed from past measurements and learning, or a relationship developed from simulations.   
     
     
         20 . The method of  claim 19 , wherein the relationship utilizes a statistical or probabilistic function, a probability distribution function, a probability mass function, a correlation function, or a covariance function. 
     
     
         21 . The machine-readable storage medium of  claim 19 , wherein the detection is based, in part, on the line-of-sight (LOS) blocking/crossing of the received signal, or multi-path (MP) scattering/fading of the received signal, or both LOS blocking/crossing and MP scattering/fading. 
     
     
         22 . The machine-readable storage medium of  claim 19 , wherein the steps further include communicating the occupancy estimate to one or more control systems, wherein the one or more control systems includes one or more of security systems, lighting systems, heating systems, cooling systems, and/or business planning/resource allocation system.