Patent ID: 6034991
Filing Date: 2000-03-07
Classification: H04L

Abstract:
A method for signal point mapping design in the context of a pulse code modulation (PCM) modem system that employs a multiple modulus conversion (MMC) procedure associated with a plurality of moduli to perform signal point mapping using a number of signal point maps, said PCM modem system transmitting L symbols per data frame, said MMC procedure producing a plurality of output values in response to an input of B bits, said method comprising the steps of:deriving a plurality of signal point maps each having a plurality of signal points associated therewith;defining P.sub.k for values of k, where: ##EQU11## and M.sub.i is the modulus associated with the i-th signal point map;defining q.sub.k for values of k, where: q.sub.k =INT(2.sup.B /P.sub.k);defining c.sub.k for values of k, where: c.sub.k =(2.sup.B -P.sub.k q.sub.k)MODULO P.sub.k-1 ;defining r.sub.k for values of k, where: r.sub.k =INT{(2.sup.B -P.sub.k q.sub.k)/P.sub.k-1 }; anddetermining a total average power associated with data transmission using said signal point maps, said determining step including the step of calculating the probabilities of transmission for each signal point contained in said signal point maps utilizing P.sub.k, q.sub.k, and c.sub.k, where said calculating step calculates the probabilities of transmission (p.sub.k,i) associated with the i-th signal point contained in the k-th signal point map in accordance with the following probability expressions:p.sub.k,i =P.sub.k-1 (q.sub.k +1)/2.sup.B when 0.ltoreq.i<r.sub.k ;p.sub.k,i =(P.sub.k-1 q.sub.k +c.sub.k)/2.sup.B when i=r.sub.k ;andp.sub.k,i =P.sub.k-1 q.sub.k /2.sup.B when r.sub.k <i<M.sub.k.2.