Detecting Presence Based on Wireless Signal Analysis

Abstract

In a general aspect, a monitoring system detects presence of an object in a space, e.g., when no motion is detected. Motion of an object in a space is detected by analyzing a first set of signals based on wireless signals transmitted in a first time period. Lack of motion in the space is detected by analyzing a second set of signals based on wireless signals transmitted in a second, subsequent time period. Whether the object was present in the space during the second time period is detected by analyzing the second set of signals.

1 .- 27 . (canceled) 
     
     
         28 . A method comprising:
 obtaining channel information based on wireless signals transmitted through a space over a time period, wherein the wireless signals are transmitted between wireless communication devices in a wireless communication network and are formatted according to a wireless communication standard; and   detecting respiratory activity that occurred in the space during the time period based on the channel information.   
     
     
         29 . The method of  claim 28 , wherein the wireless communication network is a wireless local area network (WLAN). 
     
     
         30 . The method of  claim 28 , wherein the channel information includes beamforming state information. 
     
     
         31 . The method of  claim 28 , wherein the channel information includes channel response information. 
     
     
         32 . The method of  claim 28 , comprising:
 accessing a database of stored signals, each of the stored signals being associated with an occupied state of the space or an unoccupied state of the space;   comparing the channel information with the stored signals; and   determining whether an object is present in the space during the time period based on the comparison.   
     
     
         33 . The method of  claim 32 , comprising obtaining the stored signals during a supervised motion detection training period for the space or during an unsupervised training period for the space. 
     
     
         34 . The method of  claim 28 , comprising determining that changes to the channel information are indicative of a presence of an object in the space and a lack of motion of the object in the space. 
     
     
         35 . The method of  claim 28 , wherein the wireless communication standard includes the IEEE 802.11 wireless communication standard. 
     
     
         36 . A client device comprising:
 a processor; and   memory comprising instructions which, when executed by the processor, cause the client device to perform operations comprising:
 obtaining channel information based on wireless signals transmitted in a wireless communication network through a space over a time period, wherein the wireless signals are formatted according to a wireless communication standard; and 
 detecting respiratory activity that occurred in the space during the time period based on the channel information. 
   
     
     
         37 . The client device of  claim 36 , wherein the wireless communication network is a wireless local area network (WLAN). 
     
     
         38 . The client device of  claim 36 , wherein the wireless communication standard includes the IEEE 802.11 wireless communication standard, and the client device is a Wi-Fi client device. 
     
     
         39 . The client device of  claim 36 , wherein the channel information includes beamforming state information. 
     
     
         40 . The client device of  claim 36 , wherein the channel information includes channel response information. 
     
     
         41 . The client device of  claim 36 , the operations comprising:
 accessing a database of stored signals, each of the stored signals being associated with an occupied state of the space or an unoccupied state of the space;   comparing the channel information with the stored signals; and   determining whether an object is present in the space during the time period based on the comparison.   
     
     
         42 . The client device of  claim 41 , the operations comprising obtaining the stored signals during a supervised motion detection training period for the space or during an unsupervised training period for the space. 
     
     
         43 . A non-transitory computer-readable medium comprising instructions that, when executed by data processing apparatus, perform operations comprising:
 obtaining channel information based on wireless signals transmitted through a space over a time period, wherein the wireless signals are transmitted between wireless communication devices in a wireless communication network and are formatted according to a wireless communication standard; and   detecting respiratory activity that occurred in the space during the time period based on the channel information.   
     
     
         44 . The computer-readable medium of  claim 43 , wherein the wireless communication network is a wireless local area network (WLAN). 
     
     
         45 . The computer-readable medium of  claim 43 , wherein the wireless communication standard includes the IEEE 802.11 wireless communication standard. 
     
     
         46 . The computer-readable medium of  claim 43 , wherein the channel information includes beamforming state information. 
     
     
         47 . The computer-readable medium of  claim 43 , wherein the channel information includes channel response information. 
     
     
         48 . The computer-readable medium of  claim 43 , the operations comprising:
 accessing a database of stored signals, each of the stored signals being associated with an occupied state of the space or an unoccupied state of the space;   comparing the channel information with the stored signals; and   determining whether an object is present in the space during the time period based on the comparison.   
     
     
         49 . The computer-readable medium of  claim 48 , the operations comprising obtaining the stored signals during a supervised motion detection training period for the space or during an unsupervised training period for the space. 
     
     
         50 . The computer-readable medium of  claim 43 , the operations comprising determining that changes to the channel information are indicative of a presence of an object in the space and a lack of motion of the object in the space.