Presents increasing demand of rates in any digital communication system that excites the research idea of scheduling channel access methodology so as to results in maximizing the sum rate. The reduction in feedback messages for channel state information provides great savings in channel bandwidth for multiuser switched diversity scheduling systems. The present proposed work demonstrates that maximization of sum capacity can be achieved using optimization of per user threshold rate along with some prior estimation of channel state information.The results shown in higher achievable rate. Furthermore the proposed novel multiuser switched diversity MUSD system also achieves proportional fairness criteria along with decentralization of optimization threshold channel.