Advances in MIMO Techniques for Mobile Communications—A Survey <s> MU-MIMO Capacity <s> Wireless networks are under constant pressure to provide ever-higher data rates to increasing numbers of users with greater reliability. This book is an accessible introduction to every fundamental aspect of space-time wireless communications. Space-time processing technology is a powerful tool for improving system performance that already features in the UMTS and CDMA2000 mobile standards. The ideal volume for graduate students and professionals, it features homework problems and other supporting material on a companion website. <s> BIB001 </s> Advances in MIMO Techniques for Mobile Communications—A Survey <s> MU-MIMO Capacity <s> This paper characterizes the sum capacity of a class of potentially nondegraded Gaussian vector broadcast channels where a single transmitter with multiple transmit terminals sends independent information to multiple receivers. Coordination is allowed among the transmit terminals, but not among the receive terminals. The sum capacity is shown to be a saddle-point of a Gaussian mutual information game, where a signal player chooses a transmit covariance matrix to maximize the mutual information and a fictitious noise player chooses a noise correlation to minimize the mutual information. The sum capacity is achieved using a precoding strategy for Gaussian channels with additive side information noncausally known at the transmitter. The optimal precoding structure is shown to correspond to a decision-feedback equalizer that decomposes the broadcast channel into a series of single-user channels with interference pre-subtracted at the transmitter. <s> BIB002 </s> Advances in MIMO Techniques for Mobile Communications—A Survey <s> MU-MIMO Capacity <s> Multiple-input multiple-output (MIMO) communication techniques have been an important area of focus for next-generation wireless systems because of their potential for high capacity, increased diversity, and interference suppression. For applications such as wireless LANs and cellular telephony, MIMO systems will likely be deployed in environments where a single base must communicate with many users simultaneously. As a result, the study of multi-user MIMO systems has emerged recently as an important research topic. Such systems have the potential to combine the high capacity achievable with MIMO processing with the benefits of space-division multiple access. In this article we review several algorithms that have been proposed with this goal in mind. We describe two classes of solutions. The first uses a signal processing approach with various types of transmitter beamforming. The second uses "dirty paper" coding to overcome the interference a user sees from signals intended for other users. We conclude by describing future areas of research in multi-user MIMO communications. <s> BIB003
The maximum capaci co n total transmit power constraint. The DPC achievable rate region for the case of multi-antenna users is formulated in BIB002 and i also discussed in  . Further research work is required on the capacity of fading MIMO broadcast channels. channels co c is ding is the optimal precoding strategy capable of achieving the sum capacity. In [68] , it has been proved that the capacity region of the Gaussian MIMO-BC with single-antenna users is equivalent to the dirty paper coding (DPC) rate region under a certai rlier, the downlin nformation rates of all the users BIB003 . It has been shown in BIB002 that the sum capacity of a Gaussian MIMO broadcast channel with an arbitrary no. of BS transmit antennas and multi-antenna users, is the saddle-point of a minimax problem and (assuming eal-valued signals) is given by BIB001 BIB002 H represent the rate vector, spatial covariance matrix and the channel matrix respectively for the i-th user. A general expression for the capacity regions of fading MAC channels is also given in  .