The aim of this topic is to reduce SER in MIMO System.To investigate a joint diversity scheme and various modulation schemes in a multiple-input multiple-output (MIMO) system. The exact SER of the joint diversity scheme can be derived from M-ary QAM and M-ary PSK modulations in various fading channels. By comparing various fading channels, SER will be reduced and thus performance of SNR in the MIMO systems will be improved.Whenever User increases SER reduced.