Patent ID: 9191189
Filing Date: 2015-11-17
Classification: H04B,H04L

Abstract:
1. A method for detecting a preamble in a received radio signal, the method comprising: demodulating the received radio signal based on a carrier derived from a local timing source to provide a digital signal comprising a sequence of bits oscillating at approximately a modulated data rate; determining a bit width of each successive bit of said digital signal; responsive to a pair of consecutive bit widths having a combined width within a threshold value, indicating a bit pair as potentially belonging to the preamble; responsive to detecting a threshold number of potential preamble bit pairs in a sequence of bit pairs within a given window, indicating said sequence of bit pairs as potentially belonging to the preamble; determining a statistical characteristic of at least some of said sequence of bit pairs potentially belonging to the preamble, including determining if a variance of bit widths of the sequence of bit pairs is less than a second threshold amount; and responsive to said statistical characteristic meeting a predefined criterion, confirming that said sequence of bit pairs belongs to the preamble.