Simultaneous Extraction of Data, Delay and Carrier Phase in Transform Domain Spread Spectrum Systems

It is customary practice in spread spectrum communications systems to perform the functions of data extraction, code synchronization, and carrier phase tracking with separate subsystems. Sometimes, two out of the three functions are combined in one subsystem; a Costas loop can use the square of the output of the data channel to maintain carrier lock (for bi-phase data). This paper discusses a method of extracting the basic signals for all three functions with a generalized Fourier transform correlator operating in the transform domain with the signal-to-noise ratio identical to that for traditional systems. The usual sensitivity of the typical early/late gate correlator to loss of synch after slippage of one chip time is also removed.