s well known [6] that, in cooperative antenna systems, several distributed radio stations simultaneously transmit suitably coherently precoded data signals by common beam forming over all radio stations, and antenna elements are able to overcome interference successfully. Cooperative antenna systems even exceed the performance of a single isolated cell due to rank enhancement effects [18]. For real systems, cooperation over large areas is not feasible because accurate chan- nel state information (CSI) for many base stations (BSs) and much user equipment (UE) is needed. Therefore, practical solutions for cooperative antenna systems, gener- ally termed in the following as COOPA (cooperative antenna) systems, have to been found. In addition to a classification of COOPA implementations, main challenges like channel estimation, feedback overhead, and backbone traffic overhead and pos- sible solutions like cooperative relaying will be given in this chapter. A further impor- tant topic will be the implementation of a basic cooperation area (CA) based on LTE © 2009 by Taylor & Francis Group, LLC Cooperative Transmission Schemes release 8 features with minimum adaptations to the standard as well as backward compatibility for release 8 conforming UEs and simultaneously robust operation. Introduction In the future, mobile network operators (MNOs) will have to provide broadband data rates to an increasing number of users with lowest cost per bit and probably as flat rates, such as is known from fixed network providers. Intercell interference is the most limiting factor in current cellular radio networks, which means that any type of practical feasible interference mitigation will be of highest importance to tackle the expected 100-fold traffic challenge. Cooperation is the only means known to really overcome interference and is therefore a very likely candidate for integration into an enhanced LTE system. In the beginning of 2008, the first 3GPP LTE release 8 standard emerged, defining most of its fundamental parameters and 