Required interleaving depth in Rayleigh fading channels

Existing wireless communication system usually employs an interleaver to randomize bursty errors so that they may be correctable by the FEC (forward error correction) scheme. However, without properly choosing the interleaving depth, the interleaver may have negative effects that destroy more blocks and thus increase the BER. We derive the formula for calculating the required interleaving depth under different values of the maximum Doppler frequency f_m. By using this formula we can estimate the required interleaving depth before transmission such that performance will not degrade