Patent ID: 7974349

Claim:
A perturbation method in a multi-antenna multi-user communication system, comprising the steps of: decomposing, upon receipt of modulation symbols, channel responses into eigenvalues and eigenvectors by Singular Value Decomposition (SVD) and estimating a distortion value of the modulation symbols using the eigenvectors and the eigenvalues; and precoding the modulation symbols by combining the modulation symbols with the estimated distortion value, wherein the precoded symbols are expressed as x = ⁢ P r ⁢ H - 1 ⁡ ( u + δ opt ) = ⁢ P r ⁢ H H ⁡ ( HH H + K ρ ⁢ I ) - 1 ⁢ ( u + τ ⁢ ⁢ 1 opt ) , where r is a normalization factor, u is a data vector, δ is the distortion value expressed as δ=τl+ε, ρ=P/N o , τ is a positive real number, and l is a Kx1 complex vector.