In a wireless network, users can relay information to exploit cooperative diversity, therebyrnincreasing reliability. The uses of multiple transmit and receive antennas (MIMO) can helprnto exploit transmit and receive diversity respectively. This thesis discusses the applicationrnof a technique called space time block coding (STBC) on a system based on the joint usernof cooperative diversity and MIMO schemes, which we hope intuitively that the systemrnperformance can be increased further. A source node, equipped with two transmitsrnantennas, first encodes incoming data using STBC and then broadcasts the resulting codernto relay and destination nodes. Then, the two relay nodes, each equipped with singlernantenna, either amplify-and-forward (AF) or decode-and-forward (DF) the received codesrnto the destination. The destination node combines (e.g., using maximum ratio combiningrn(MRC)) signals received from the sourceâ€™s and relayâ€™s antennas and decodes the combinedrnsignal in order to recover the original data. As the signals from the source and relay arernreceived through different paths, which are assumed to be spatially independent, spatialrndiversity can be exploited. Compared with point-to-point transmission system and simplernAlamouti STBC system with no relays, AF based STBC system obtains one additionalrnbenefit, achieving spatial diversity offered by the relays. Moreover, the STBC-based DFrncooperative system has two additional benefits. First, it achieves the spatial diversityrnoffered by the relay channel and secondly, it has the ability to introduce the characteristicsrnof STBC into the relay system. In addition, the system model and performance evaluationrnof these systems in various channel conditions and modulations (using simulation) will bernaddressed.