Patent ID: 7567634

Claim:
A baseband processing unit for decoding symbols defining modulated data, comprising: a channel estimator to generate a channel estimate for each of the symbols; and a Viterbi decoder, comprising: a branch metric computation unit to compute a plurality of branch metrics responsive to the channel estimate and based on the symbol, channel state information associated with the symbol, and a piecewise bit-by-bit approximation; and a most-likely codeword estimator to estimate a transmitted coded bit sequence based on the plurality of branch metrics computed by said branch metric computation unit for a plurality of said symbols, wherein said branch metric computation unit computes the plurality of branch metrics using BM k,n,i =−(| Z k,n,i |−|H k,n 2 ·m )·sign( b i ) wherein BM k,n,i is a branch metric, k is a subcarrier identifier, n is a symbol identifier, Z k,n,i is equal to H k,n * ·Y k,n where H k,n * is a channel estimate and Y k,n is a received noisy symbol, m is a modulation variable, bε{±1}, and iε{0,1}.