Patent ID: 7010052
Filing Date: 2006-03-07
Classification: H03M

Abstract:
1. Method of building systematically a multi-dimensional (n, D, L) circular trellis coded modulation (CTCM) encoder with properties of optimal energy efficiency, strong tail biting and maximum minimum distance (d min ) of trellis paths, where n is the size of the symbol alphabet, D is the depth of the trellis, and L is the length of the information symbol sequence, said method comprising the steps of: a) identifying simplex-transition sets of originating and next states for each stage i of a circular trellis; wherein a simplex is a set of M signals in an N-dimensional space with N≧M−1, satisfying that for all I, j∈{1, 2, . . . , M}, the cross-correlation between signals s for normalized signal energy. The M signals have equal distance from each other; b) determining butterfly structures (butterflies) associated with the identified simplex-transition sets wherein the originating and next states of said simplex-transition sets are arranged in an internal order within said butterfly structures; c) aligning said butterfly structures into a multi-dimensional state transition matrix (STM) in a predetermined order; d) constructing a simplex of channel symbols from a multi-dimensional signal constellation space for each of said identified simplex-transition sets; e) aligning each simplex of channel symbols into a multi-dimensional initial input simplex (IIS) matrix in an order in relation to said predetermined order of butterfly structures in said STM; and f) assigning channel symbols to state transitions of a trellis path by mapping between said simplex-transition sets of the STM and said simplexes of symbols of said IIS matrix.