Abstract: Various presence detection techniques are disclosed. In some embodiments, a system comprises a signal generator configured to generate a signal that includes a plurality of selected frequencies that are selected from among a set of candidate frequencies, wherein inclusion or exclusion of each candidate frequency in the signal encodes a bit of information and wherein the encoded information comprises a store identifier that identifies a retail store; and a transmitter configured to transmit the signal within the retail store; wherein presence of a device in the retail store is determined in response to reception of the signal at the device and extraction of the store identifier from the received signal by decoding the received signal.

Abstract: Various presence detection techniques are disclosed. In some embodiments, a system comprises a signal generator configured to generate a signal that includes a plurality of selected frequencies that are selected from among a set of candidate frequencies, wherein inclusion or exclusion of each candidate frequency in the signal encodes a bit of information and wherein the encoded information comprises a store identifier that identifies a retail store; and a transmitter configured to transmit the signal within the retail store; wherein presence of a device in the retail store is determined in response to reception of the signal at the device and extraction of the store identifier from the received signal by decoding the received signal.

Abstract: The transmission system transmits an encrypted identifier ultrasonically in an open-air environment using an ultrasonic transmitter. The ultrasonic identifier is associated with a location, which may be a store or a department within a store, and may be received by a microphone on a mobile phone. The identifier may be used to infer presence of the mobile phone user at the location associated with the identifier. The transmitter may include an ultrasonic transducer. The system may further provide a reward, responsive to inferring presence at the location.

Abstract: Presence detection using Bluetooth and hybrid-mode transmitters is disclosed. In some embodiments, a transmitter is configured to broadcast a secure identifier comprising a venue identifier using Bluetooth Low Energy (BTLE) and/or an ultrasonic audio channel. The secure identifier broadcast by the transmitter is captured by a handset and decoded to infer presence of the handset at a venue identified by the venue identifier.

Abstract: Presence detection using Bluetooth and hybrid-mode transmitters is disclosed. In some embodiments, one or more transmitters are configured to transmit an iBeacon broadcast and a proprietary Bluetooth Low Energy (BTLE) broadcast, wherein at least one of the transmitted broadcasts includes an identifier that specifies a venue. The broadcasts are captured by a handset and decoded to infer presence of the handset at the venue.