Multi-user MIMO Downlink User Selection Algorithm

With the coming of the age of information, we say goodbye to the outdated ways of information transmission, such as Yi Guan Inn, IP Messenger, telegraph, hand phone, and the later BP machine etc. These are once used to transmit information, but they can only pass a simple message. Especially as people's living standard continuously improves, their requirements on various parts are gradually increased. Now people do not simply want to pass a simple message but also want to put more information to each other. Therefore, in order to meet these continuous needs communication systems are on the forward way of rapid development.The mobile communication with which we are so familiar has evolved from 1 G era at the very beginning soon into the 2 G or even 3 G era. Nowadays we can not only deliver a message, but also make graphic video transmission, and do electronic commerce through the wireless network. Even so, it can't satisfy the requirements of the people, because people need better transmission quality and faster transmission speed, while the bandwidth resources of wireless communication can not be expanded limitlessly. This is the very problem we are facing.The spatial information can be introduced into communication system by allocating antennas for the transmitter and the receiving end, then it can enhance the transmission speed of the MIMO system, which has become a hot topic of today's study after being put forward in the middle of 1990s.MIMO multiuser system can communicate with multi-users at the same time on the condition that it needn't constantly increase the amount of spectrum resources and expand the intervals. Apart from this aspect, it can take full advantage of SDMA (Space Division Multiple Access),so MIMO multiuser system can make use of channel resources much better than single user system can for. However, we could not be ignorant of such a situation that the amount of users working simultaneously is limited, and the amount of transmitting-receiving antennas is also a problem.The sender of the MIMO multiuser system should adopt feasible algorithm and some mechanism to confirm the amount of these users communicating with it in practical application. In order to ensure and satisfy Qos requiremnts such as SINR and equality, the management of access user, or multiuser scheduling becomes necessary.When there exists a few users, then how to choose a user becomes a desperate question. And this paper places much emphasis on the user selection algorithm.1) Briefly introduce some main concepts, system model of MIMO system, the current research status and the capacity of information channel.2) Put forward dispatching algorithm on how to realize the equality among users in MIMO system.