From: Optimality of beamforming condition for multiple antenna systems with mean feedback
Antenna pair
(2, 1)
(2, 2)
(4, 2)
(4, 4)
∑ μ
λ1μ= 1.414
(λ1μ, λ2μ) = (1.78, 0.9)
(λ1μ,λ2μ) = (2.74, 0.69)
(λ1μ,λ2μ, λ3μ, λ4μ) = (3.66, 0.92, 0.92, 0.92)