Patent ID: 6957381

Claim:
A method for creating a look-up table to determine a branch metric of a received symbol of a modulated digital waveform wherein said received symbol is represented by a point on a plane comprising two orthogonal axes, said method comprising the steps of: (a) providing a locus of points on said plane representative of the set of potential received symbols; (b) designating one of the points of said locus of points as a first reference point; (c) providing a second reference point on said plane; (d) for each point of the locus of points: (i) determining the angle between a line connecting said point and said second reference point and a line connecting said second reference point and said first reference point; and (ii) calculating the branch metric value as a function of the distance between said point and said first reference point; and (e) populating a table with the branch metric values and indexing the table with the respective angle measurements to thereby create a look-up table.