Patent ID: 7751506

Claim:
A method of soft bit metric calculation for received data signals via a channel in a telecommunications receiver utilizing Low Density Parity Check (LDPC) decoding, comprising: detecting data symbols in the received signals by applying a linear Multiple-Input Multiple-Output (MIMO) detection, wherein the linear MIMO detection comprises determining distances between the detected data symbols and constellation points; determining a noise variance of the channel; calculating the soft bit metrics as a function of the distances between the detected data symbols and the constellation points, and calculating a channel noise variance matrix E[vv H ], wherein the distances are divided by the noise variance, wherein calculating the soft bit metrics further includes: selecting diagonal elements of the channel noise variance matrix E[vv H ], and calculating the soft bit metrics as a function of the distances and σ v 2 , where the diagonal elements σ v 2 is defined as: σ v 2 =E[diag{vv H }] =σ n 2 diag{WW H }, W is a linear filter and W H is a pseudo-inverse of W, σ n 2 represents the noise variance and v is a new noise term and v H is a pseudo-inverse of V.