Wireless communication systems with multiple antennas are the focus of many applicationsrnnowadays due to the higher throughput and/or more robust performance than single antennarncommunication. One variety of these systems is the multi-user system in which many usersrnshare the same wireless environment. In this thesis, communication strategies that use dirtyrnpaper coding (DPC) techniques to form independent spatial streams to the Multiple InputrnMultiple Output broadcast channel (MIMO BC) are studied. Unlike previous studies thatrnassume ideal channel conditions, the performance of DPC algorithms under frequencyrnselective channels having spatially correlated path gains is investigated. These algorithms arernfound to be equally applicable to frequency selective channels if orthogonal frequencyrndivision multiplexing (OFDM) is employed with 1.5 dB power loss due to correlation forrnrealistic correlation values.rnThe second part of the thesis considers issues that arise in practical implementation of thernDPC algorithms. The effect of imperfect channel estimates at the transmitter and the problemrnof scheduling users for transmission are considered. For time division duplex (TDD) systems,rnwe show that errors in channel estimation result in performance degradation that can almostrncompletely be eliminated above a SNR of 25 dB. For frequency division duplex (FDD)rnsystems, it is shown that delay in estimation feedback results in severe performancerndegradation that becomes unacceptable above some delay depending on the algorithm used.rnUser scheduling is formulated as user selection for single carrier systems. We adapt anrnalgorithm proposed for linear pre-coding techniques and show there is an increase in sum raternin using this algorithm over uniform scheduling of users. For OFDM systems, applying thernuser selection algorithm proposed for single carrier systems to each subcarrier results inrnincreased sum rate with lower fairness index compared to uniform scheduling. Allowingrnusers to select their strongest subcarriers, on the other hand, is shown to give lower sum raternand improved fairness compared with the sum rate maximizing algorithm.rnKey words: Dirty Paper Coding, MIMO Broadcast Channel, Pre-coding