Advances in Coordinated Multi-Cell Multi-User MIMO Systems

Feedback CSI Variations
• Adopt coefficient of variation (CV) to evaluate the impact
of feedback CSI variations
– Perturbed from the noisy estimated information, the
outdated information, and quantization errors, etc.
– For random variable X, CV = σ x / E[X]
• For the feedback CSI x, the perturbed feedback CSI
received at BS is
x’ = x +
– ~ N(0, σ x2 ) and σ x = CVx