Discrete adaptation of type-II hybrid-ARQ in DS-CDMA

Abstract

The paper presents an optimisation strategy based on discrete adaptation of the code rate given the modulation scheme in direct spread code division multiple access (DS- CDMA) communication system. The adaptive algorithm maximizes spectral efficiency across a fading channel by transmitting an optimal amount of incremental bits on each transmit attempts. The justification presented is based on a type-II hybrid-ARQ employing turbo punctured codes with multilevel signalling.