A Low-Power Preamble Detection Methodology for Packet Based RF Modems on All-Digital Sensor Front-Ends

There is a growing trend towards networks of sensors in which each sensor wirelessly transmits digital data to a central data collection node. The transmission of sensor measurements relies on its digitized data being organized as a set of bits. This sequence or frame contains preamble information (the preamble is used to signal that "here is a train of data coming" to the receiver), a data sequence, and finally "end of signal" bits. In order to achieve frame synchronization in packet-based communication systems, a known sequence (pre-amble) is sent at the beginning of each packet. This paper presents a low power scheme for preamble detection using dynamic precision configuration. The proposed scheme is based on the observation that signal processing algorithms at the front end (including mixer, square root raised cosine (SRRC) matched filter and code matched filter (CMF)) of the receiver, can be operated with minimum precision during the acquisition phase without incurring significant acquisition performance degradation. The SRRC filter is designed to achieve minimize inter-symbol interference, while the CMF is designed to improve the signal to noise ratio. The result is an acquisition system design that consumes less than 25% of power dissipation that is consumed by other typical implementations.