Patent ID: 6259742
Filing Date: 2001-07-10
Classification: H04L

Abstract:
A shell mapping method, said method comprising the steps of:receiving digital data in a shell mapper;determining the lowest cost N-tuples in accordance with an approximated cost function, wherein N is the mapping frame size, said approximated cost function is proportional to 2.sup.k, and k is a ring index; andmapping K data bits of said digital data uniformly onto an output including 2.sub.k, of said lowest cost N-tuples, wherein said determining step comprises the steps of:dividing a pulse code modulation constellation into M rings, each of said rings being associated with said ring index k; anddefining said approximated cost function associated with a kth ring as ##EQU9##wherein a.sub.2 =f(k+1), a.sub.1 =f(k) is an exponential function in k.