Methods and apparatus for optimizing shell mapping techniques using an approximated power cost function

摘要

To compensate for the substantially non-uniform spacing of constellation points in a pulse code modulation modem, the transmitting power efficiency is substantially maximized while substantially limiting the complexity of the mapping. To optimize the transmitting power efficiency, the present invention suitably determines an approximate cost function g(n) to reduce the complexity and the 2^K lowest cost N-tuples (m₀,m₁, . . . ,m_N-1) for power transmission efficiency. Knowing the lowest cost N-tuples, fractional K data bits are systematically mapped uniformly onto the 2^K lowest cost N-tuples.