Spatial Modulation (SM) and Space Shift Keying (SSK) modulation has been recently proposed as a new transmission approachs for MIMO systems. These modulations need only one RF chain for data transmission, due to the working mechanism of SM, which only one antenna is activated for data transmission at any signaling time interval. Eliminating Inter Channel Interfrence (ICI), simple transiever design, avoiding inter antenna synchronization and increasing the spectral efficiency without increasing the bandwith requirement are the among advantages of this technique. However, this modulation is not able to achieve transmit diversity gain. The diversity order of this technique is equal to the number of receive antennas. To deal with this problem, several antenna selection algorithms based on feedback are introduced in this thesis. Transmit antennas are divided into K groups including the same number of antennas. The receiver selects one group in each transmission block using a proposed criterion for selecting the antennas according to CSI at each signaling time interval. Then, the receiver sends the group index to the transmitter through ideal feedback channel to be used for sending information. Then the transmitter turns on an antenna in the corresponding antenna group and sends the information bits. In each chapter, the Average Bit Error Rate (ABER) performance of the proposed criteria is calculated (exactly or in special case or upper bound). The results of Monte Carlo simulation and numerical analysis shows the increasing of the diversity gain of the system. Key Words : MIMO, Spatial Modulation, SSK, Transmit Diversity.