Hung-Quoc Duc Lai (University of Maryland, College Park), “Wireless network cocast: Cooperative communications with space-time network coding”, Advisor: Prof. K. J. Ray Liu (2011) Abstract: Traditional cooperative communications can greatly improve communication performance. However, transmissions from multiple relay nodes are challenging in practice. Single transmissions using time-division multiple access cause large transmission delay, but simultaneous transmissions from two or more nodes using frequency-division multiple access (FDMA), code-division multiple access (CDMA), or distributed space-time codes are associated with the issues of imperfect frequency and timing synchronization due to the asynchronous nature of cooperation. In this dissertation, the author proposed a novel concept of wireless network cocast (WNC) and developed its associated space-time network codes (STNCs) to overcome the foretold issues. In WNC networks, each node is allocated a time slot for its transmission and thus the issues of imperfect synchronization are eliminated. To reduce the large transmission delay, each relay node forms a unique signal, a combination of the overheard information, and transmits it to the intended destination. The combining functions at relay nodes form a STNC that ensures full spatial diversity as in traditional cooperative communications. The author applied the STNCs to multiuser cooperative networks. Furthermore, the author proposed a location-aware WNC scheme to reduce the aggregate transmit power and achieve even power distribution among the user nodes in the network. For details, please access the full thesis or contact the author.