Abstract— Cooperative transmission is an emerging communication technique that takes advantages of spatial diversity and broadcast natures of wireless channels to improve wireless channel capacity. However, cooperative transmission can be vulnerable to malicious attacks, especially in its current design. In this paper, we examine whether the cooperative transmission still have performance advantages when we consider the security issues. In particular, we identify various attacks against cooperative transmission, analyze the vulnerabilities of current schemes, design a trust-assisted cooperative transmission scheme, and evaluate the proposed scheme through analysis and simulations. The proposed scheme can fix the security problems and maintain the performance advantage. It performs much better than the traditional scheme when there are malicious/greedy relays or severe channel estimation errors. In addition, we investigate the advantage of cooperative transmission in terms of defendi...