Recently, cooperative communications have gained much attention due to the ability to explore the inherent spatial diversity in relay channels. Most of the ongoing research efforts in cooperative diversity assume frequency flat channels with perfect channel knowledge. However, in practical scenarios, e.g., broadband wireless networks, these assumptions do not apply. Frequency-selective fading and imperfect channel knowledge are indeed more realistic assumptions. The development of equalization and channel estimation algorithms play a crucial element in the design of digital receivers as their accuracy determine the overall performance. This book creates a framework for the design and development of various time and frequency domain equalization schemes for broadband cooperative communications. Furthermore, various non-coherent and channel estimation algorithms to improve the quality and reliability of wireless communication networks are proposed and analyzed. Finally, the effect of multiple antennas deployment in cooperative networks assuming different relaying techniques is investigated.