Multi-antenna Broadcast Channel Optimal User Coding Sequence And Its Applications

This thesis addresses the problem of minimizing the total transmit power subject to individual rate constraints in broadcast channel with multiple antennas at the transmitter and one antenna at each receiver. From information theoretical considerations, the capacity region of a broadcast channel is achieved with the dirty-paper coding (DPC) technique. Two efficient algorithms to choose the best possible user ordering for DPC are proposed. In the first algorithm, we use Simulated Annealing (SA) to deal with the combination optimization problem which was obtained by using duality of Broadcast and Multiple-access channel. In the second algorithm, we develop one already existed approach by carefully choosing its initial value. Experiment results show that the speed is increased by about 20%. What's more, we observe that original approach may experience oscillation under certain conditions. Efficient algorithm is proposed by us to detect and solve this oscillation.On the basis of the minimal power obtained by above method, we compare the advantages and disadvantages of different multiple access techniques. It is shown that non-orthogonal approaches have a spectral-power efficiency advantage over orthogonal ones for delay sensitive applications in fading environments, and that this theoretical advantage can be realised in practice by exploiting recent progress in transmission and detection techniques. The practical aspects of these multiple access techniques are also discussed and compared. The hybrid schemes, which combine the advantages of both orthogonal and non-orthogonal techniques, can provide promising solutions for future wireless cellular communications.