Asynchronous wireless sensing

Abstract

Low-complexity asynchronous wireless sensing and communication architecture is disclosed for low power wireless sensors. Schemes are based on asynchronous digital communications and Ultra-Wideband impulse radios. In asynchronous radio, combination of frequency-shift-keying (FSK) and on-off-keying (OOK) to remove clock synchronization is applied. Improved asynchronous non-coherent transmitters and receivers achieve both low power and low complexity while seamlessly combined with asynchronous level-crossing modulation. Both uncoded and coded asynchronous communication may be utilized. Coded asynchronous communication may use error correction. Forward error correction schemes for asynchronous sensor communication are utilized where dominant errors consist of pulse deletions and insertions, and where instantaneous encoding takes place. Forward error correction is also accomplished where a continuous-time sparse waveform signal is asynchronously sampled and communicated over a noisy channel via Q-ary frequency-shift keying. Concatenated code employs outer systematic convolutional codes and inner embedded marker codes that preserve timing information and protect against symbol insertions and deletions.