Carrier phase recovery employs a single-axis blind cost criterion from the
Bussgang class of functions, and its stochastic gradient, to generate a carrier
phase error used to adjust a received and demodulated signal to near baseband.
For one implementation, the estimate is derived in accordance with a Single-Axis
Constant Modulus (SA-CM) criterion and its stochastic gradient via a SA-CM algorithm
(SA-CMA). The carrier phase error is then used to adjust the carrier frequency
and phase of the received and demodulated signal toward the frequency and phase
of the carrier used to modulate the transmitted symbols, driving the carrier phase
error to zero. The values used for the phase recovery may be either i) an IIR filtered
signal, ii) a processed signal (e.g., decisions for the signal symbols), or iii)
an equalized and processed signal.