A MIMO protocol for camera communications (CamCom) using undersampled frequency shift ON-OFF keying (UFSOOK)

Abstract

Camera communications is the use of an image sensor to receive LED modulated data. The undersampling properties of UFSOOK allows the encoding of bits at frequency shift ON-OFF keying frequencies that avoid flicker while at the same time being successfully decoded by a low frame rate camera. PWM dimming is supported via data modulation of the PWM frequency, but requires that FEC be added in the form of multi-phase sampling due to asynchronous clocking. Multiple LEDs can be modulated to send parallel data streams to the receiver enabling MIMO. This paper introduces a simple protocol that will allow the transmitter to inform the receiver how the MIMO data streams should be processed to realize the FEC and reconstruct the transmitted message.