Fig. 2From: Performance analysis of cooperative cognitive MIMO multiuser downlink transmission with perfect and imperfect CSI over Rayleigh fading channelsOutage performance comparison among the exact result, lower bound, and high SNR approximation with different correlation coefficients (M = 2, N 1 = N 2 = 2, ω 1 = ω 2 = 1, Ω3 = Ω4 = 2) (a) ρ 1 = ρ 2 = 0.3; (b) ρ 1 = ρ 2 = 0.5; (c) ρ 1 = ρ 2 = 0.8; (d) ρ 1 = ρ 2 = 1Back to article page