Increasing data rates in wireless devices is particularly challenging due to the presence of many impairments in the medium, including multipath fading. Diversity techniques are a means of increasing transmission reliability in multipath environments. This thesis focuses on cooperative diversity, a concept that obtains spatial diversity via relaying. Cooperative diversity encompasses a broad range of issues, from the physical layer through network layer, making the emerging reconfigurable technology of software-defined radio ideal for experimentation.  The main contribution of this work is the development of an extendable experimental framework for implementation and analysis of cooperative protocols. A decode-and-forward (DF) relay network is constructed and analyzed by means of received symbol distributions and bit error rate (BER) versus signal-to-noise ratio (SNR) curves. The former shows a shift in the distribution of instantaneous SNR for both simple and selective DF, while the latter indicates that only the selective scheme actually achieves a diversity gain.