Efficient Acquisition Algorithm for Burst Transmission, Low-SNR Signals in the Presence of Symbol Timing and Carrier Frequency Offsets

Abstract

Typical communications systems use infrastructure to perform synchronization in order to facilitate fast and efficient transmissions between devices. In covert scenarios or mobile ad-hoc network (MANET) systems, this infrastructure may be unavailable and require synchronization through other means. On top of this, MANETs often have strict resource and power restrictions that require acquisition algorithms to be efficient. In low-signal-to- noise ratio (SNR) environments channel impacts can introduce symbol timing and carrier frequency offsets, which further complicates initial acquisition. This thesis proposes an efficient algorithm for acquiring low-SNR signals in the presence of timing and carrier frequency offsets for use in MANET systems. Further emphasis is placed on low probability of detection (LPD)/low probability of intercept (LPI) situations requiring only single transmissions and where jamming interference may be present as well. Frequency domain analysis is employed in order to reduce computational complexity and to inherently allow for the ability to spectrally notch interference present in the signal. Statistical approximations for output magnitudes are found in order to estimate receiver operator characteristic (ROC) performance without the need for simulations. Interpolation between grid points is also introduced to improve coarse offset estimation at little computational cost.