comnum.random_delay_correlation

comnum.random_delay_correlation(n, paths, max_delay, tau_rms=None, first_at_zero=False, n_fft=None)

The correlation matrix of n adjacent subcarriers of a channel of paths impulses with delays uniform over [0, max_delay] samples (Edfors et al. 1998, Sec. II): equal powers (tau_rms=None, their uniform channel) or exp(-tau / tau_rms), the first impulse at 0 with first_at_zero (their synchronized channel).

Parameters:

• n (int) – the subcarriers.

• paths (int) – the impulses.

• max_delay (float) – the largest delay (samples of the IFFT).

• tau_rms (float, optional) – the decay of the powers (samples).

• first_at_zero (bool) – the first impulse at delay 0.

• n_fft (int, optional) – the IFFT size, n by default.

Returns:

the n x n correlation (complex128), of unit diagonal.

Return type:

numpy.ndarray

Raises:

ValueError – for no subcarrier or impulse, a negative delay or a non-positive decay.