Patent ID: 7881394

Claim:
A device for estimating log-likelihood ratio (LLR) decoder metrics from a soft decision having an in-phase component and a quadrature component, the soft decision having been demodulated in accordance with a sixteen-ary quadrature amplitude modulation (16QAM) scheme, the device comprising: a first multiplier configured to multiply the in-phase component by a first constant value to generate a first LLR metric; a second multiplier configured to multiply the quadrature component by the first constant value to generate a second LLR metric; a first module configured to subtract a product of a carrier-signal-to-interference (C/I) ratio and a second constant value from an absolute value of the second LLR metric to generate a third LLR metric; and a second module configured to subtract the product of the C/I ratio and the second constant value from an absolute value of the first LLR metric to generate a fourth LLR metric.