An investigation towards unequal modulation For 802.16 systems based on bivariate modelling

The low feedback link adaptation technique based on MIESM (mutual information based exponential SNR mapping) has been extensively used in the literature for 802.16 based systems. The previous work on MIESM uses equal modulation order for all the subcarriers in an OFDM block. We have proposed the concept of unequal modulation for the subcarriers in the single OFDM block, and derived a mathematical model based on bivariate Gaussian distribution. Based on this a low feedback link adaptation algorithm has been proposed and results has been quoted for different modulation order and code rate.. Results has been produced to show that unequal modulation follows bivariate Gaussian distribution and as application, image transmission and reception using OFDM modulation for equal and unequal modulation has been generated.