A technique for multidimensional symbol and multiplexing frame synchronization in multidimensional trellis coded modems using non-standard baud

Multidimensional trellis-coded modems use symbols that are formed from multiple two-dimensional QAM (quadrature amplitude modulated) symbols. The receiver must have the ability to determine the start point of the multidimensional symbol. In modems that use a baud other than 2400 it may be necessary to multiplex channels at standard bit rates. This requires synchronization of frames of symbols that contain a number of bits that is evenly divisible by the number of multiplexed channels. An algorithm has been developed which solves both problems simultaneously. The algorithm is presented along with an explanation of its operation