  As a metric for amplitude fluctuation of orthogonal frequency division
multiplexing (OFDM) signal, cubic metric (CM) has received an increasing
attention because it is more closely related to the distortion induced by
nonlinear devices than the well-known peak-to-average power ratio (PAPR). In
this paper, the properties of CM of OFDM signal is investigated. First,
asymptotic distribution of CM is derived. Second, it is verified that 1.7 times
oversampling rate is good enough to capture the CM of continuous OFDM signals
in terms of mean square error, which is also practically meaningful because the
fast Fourier transform size is typically 1.7 times larger than the nominal
bandwidth in the long-term evolution (LTE) of cellular communication systems.
