  High variations in the OFDM signal envelope cause nonlinear distortion in the
power amplifier of the transmitter, which is a major drawback. Peak-to-Average
Power Ratio (PAPR) and Cubic Metric (CM) are commonly used for quantifying this
characteristic of the signal. Despite the reportedly higher accuracy compared
to PAPR, limited research has been done on reduction algorithms for CM. In this
paper, the Method of Conditional Expectations (CE Method) is used to achieve CM
reduction by the Sign Selection approach. Using the CE Method, the amenable
mathematical structure of CM is exploited to develop a low complexity
algorithm. In addition, guaranteed reduction is analytically proved for every
combination of the data symbols. Simulations show a reduction gain of almost 3
dB in Raw Cubic Metric (RCM) for practically all subcarrier numbers, which is
achieved using only half the full rate loss of the Sign Selection approach.
