A new method proposed by UCSB researchers has enabled crowd counting through walls using only WiFi
Researchers in UC Santa Barbara professor Yasamin Mostofi’s lab have given the first demonstration of crowd counting through walls using only everyday communication signals such as WiFi. The technique, which requires only a wireless transmitter and receiver outside the area of interest, could have a variety of applications, including smart energy management, retail business planning and security.
“Our proposed approach makes it possible to estimate the number of people inside a room from outside,” said Mostofi, a professor of electrical and computer engineering at UC Santa Barbara. “This approach utilizes only WiFi RSSI measurements and does not rely on people to carry a device.”
Their research findings appeared in the 2018 IEEE PERCOM conference, as well as in their other related publications such as 2018 IEEE SECON and 2018 IEEE SAM.
In the team’s experiments, one WiFi transmitter and one WiFi receiver are behind walls, outside a room in which a number of people are present. The room can get very crowded with as many as 20 people zigzagging each other. The transmitter sends a wireless signal whose received signal strength (RSSI) is measured by the receiver. Using only such received signal power measurements, the receiver estimates how many people are inside the room — an estimate that closely matches the actual number. It is noteworthy that the researchers do not do any prior measurements or calibration in the area of interest; their approach has only a very short calibration phase that need not be done in the same area.
This development builds on previous work in the Mostofi Lab, which has pioneered sensing with everyday radio frequency signals such as WiFi, with several publications in this area since 2009. For instance, their 2015 paper showed crowd counting without relying on people to carry a device, but with the transmitter and receiver in the same area as the people.
“However, enabling through-wall crowd counting is considerably more challenging due to the high level of attenuation by the walls,” said Mostofi. Her lab’s success in this endeavor is due to the new proposed methodology they developed.
Key to this technology is that human presence and movement can result in significant drops — thought of in this project as “events” — in the received signal strength.
“Consider the event sequence that corresponds to the occurrence of significant signal drops,” Mostofi said. “An inter-event time is then the time in between two consecutive events.” The researchers’ approach for enabling through-wall crowd counting is based on mathematically characterizing the information content of the received signal inter-event times, and relating it to the total number of occupants.
“We have observed that while the signal magnitude can be severely attenuated through walls, the inter-event times corresponding to the events of significant signal drops are more robust to wall attenuations,” Said Saandeep Depatla, the lead Ph.D. student on this project. Thus, the researchers’ approach is based on exploiting these inter-event times.
More specifically, by modeling the event sequence corresponding to the significant signal drops as a renewal-type process, the researchers have utilized mathematical tools from renewal process literature, a theoretical field that has found applications in areas such as reliability and risk analysis. After a long derivation, the researchers were able to mathematically model the statistics of the inter-event times and explicitly relate them to the total number of occupants in the area.
The Mostofi Lab has tested their new technology extensively, in different locations, with different wall properties and with several different numbers of people — up to and including 20. They showed a counting accuracy of 2 people or less 100 percent of the time with only one WiFi link. It is further noteworthy that their setup consists solely of off-the-shelf WiFi transceivers.
Learn more: Crowd Counting Through Walls with WiFi
The Latest on: WiFi
via Google News
The Latest on: WiFi
- Roberto Bautista Agut apologises after likening Australian Open quarantine to prison with wifion January 19, 2021 at 7:40 am
Former Wimbledon semi-finalist Roberto Bautista Agut has been forced to apologise after likening quarantine conditions before the Australian Open to prison “but with wifi”.
- Service disruptions reported across Leander ISD; impacting WiFion January 19, 2021 at 7:31 am
An outage is affecting service disruptions across the entire Leander ISD, the district said Tuesday morning. The district said at around 8:30 a.m. that the outage is affecting wireless devices ...
- Qualcomm's Snapdragon 870 is a faster 865, but without WiFi 6Eon January 19, 2021 at 6:30 am
Qualcomm has tweaked its Snapdragon 865 smartphone processor yet again to create the Snapdragon 870, bumping up the CPU speed but eliminating Wi-Fi 6E.
- Samsung's latest rugged tablet gets a Dex and WiFi 6 updateon January 19, 2021 at 6:00 am
If you thought Samsung was done with its announcements this month, think again. After showing off a slew of new TVs, the Galaxy Chromebook 2, robots, the Galaxy Buds Pro, Galaxy Smart Tags and the ...
- Broadcom is the supplier of the WiFi 6E chips for Galaxy S21 Ultraon January 19, 2021 at 12:21 am
Fi 6E chips that is used by Samsung for its high end Galaxy S21 Ultra. The known chipmaker supplies the BCM4389 chips for the premium grade flagship handset. For those unaware, the Samsung Galaxy S21 ...
- Roberto Bautista Agut likens Australian Open quarantine to being in prison 'but with wifi'on January 18, 2021 at 8:50 pm
Spanish tennis player Roberto Bautista Agut has likened Australian Open quarantine in Melbourne to being in prison and laid the blame solely with the Victorian government. Frustration and confusion ...
- Tennis-Bautista Agut says hotel quarantine like jail with Wifion January 18, 2021 at 7:04 pm
Roberto Bautista Agut has slammed the Victoria state government's quarantine requirements for tennis players ahead of next month's Australian Open and said being locked down in a hotel is like being ...
- Who deserves the wifi? The war is on in my house – and I am losingon January 17, 2021 at 10:00 pm
The pinnacle was wifi, and that was pretty simple: if you had proper work, you deserved it, and if you were trying to keep a pig alive in Minecraft, you could be kicked off as the situation demanded.
- Tips to improve WiFi around the houseon January 15, 2021 at 10:00 pm
Speedy, reliable internet is something people have quickly grown accustomed to. ThatÕs no doubt why dropped WiFi signals can be so frustrating.
via Bing News