The goal of this special session is to highlight optimization techniques for multi-user MIMO communications both in cellular networks and in ad-hoc mode. This session will highlight recent advances in multi-user MIMO techniques on the physical-, medium access-, and radio link control layers. Currently, little is published about how to optimally leverage the new degrees of freedom resulting from MIMO terminals in a multi-user context. The wireless industry has started to integrate single-user MIMO techniques into existing multi-user cellular standards and to define new cellular standards based on MIMO. Wireless networks should not be regarded as a set of concurrent point-to-point links. More appropriate models are many-to-one links where many users transmit to a single base station and one-to-many links where a single base station transmits to many users.