Patent ID: 8792304

Claim:
A method for transmitting a command from a surface location to a bottom hole assembly located in a borehole, the method comprising: (a) pumping drilling fluid downhole through a drill string to the bottom hole assembly; (b) changing a flow rate of the drilling fluid to encode a downlinking signal, the downlinking signal including at least a synchronization phase and a command phase, each of the synchronization phase and the command phase including at least one distinct pulse; (c) detecting the downlinking signal at the bottom hole assembly; (d) causing a downhole controller to differentiate the downlinking signal; (e) causing the downhole controller to decode the synchronization phase to determine at least one of a bit length and a duration of the command phase; and (f) causing the downhole controller to decode the command phase to determine the command based on at least one of the bit length and the duration determined in (e).