Average level crossing rate and fade duration of maximal ratio diversity in unbalanced and correlated channels

The average level crossing rate (LCR) and average fade duration (AFD) of a maximal ratio combining (MRC) system, operating on unbalanced Rayleigh fading branches are derived in closed-form for dual-branch diversity, and as a single definite integral for three-fold diversity and as a two-fold definite integral for four-fold diversity. The more general case where the Rayleigh or Ricean diversity branches have arbitrary cross-correlations is examined and it is shown that it can be converted to an equivalent independent and unequal power case. Analytical results for the average LCR and AFD of MRC in correlated Rayleigh fading are presented.