Research On The Downlink Pre-Coding Technology In Distributed Antenna Systems

With the rapid development of mobile Internet, the increasing popularity of intelligent terminals and the emergence of a variety of multimedia services such as web browsing, social networking, mobile games, e-commerce and high-definition video, higher demands and challenges are put forward for the speed and quality of mobile communication systems. The distributed antenna technology has become an important candidate for future mobile communications because it can effectively increase the capacity and spectral efficiency of communication systems. The coordinated multi-point transmission technology based on distributed antennas has been adopted in LTE-Advanced and IEEE 802.11m standards. The downlink pre-coding technology of distributed antenna systems is studied in this thesis.Firstly, the fundamental principles of MIMO multiple antennas and distributed antennas technologies are introduced. The research progress of distributed antenna systems and the downlink pre-coding technology are also overviewed.Secondly, the channel model and related property of distributed antenna systems are studied. Combining with the MIMO multiple antenna and distributed antenna technology, the coverage and the channel capacity are focused on. The simulation results show that the coverage and the channel capacity performances of distributed antenna systems are better than that of centralized antenna systems.Thirdly, the downlink pre-coding technology of distributed antenna systems for a single cell is investigated. Some traditional pre-coding schemes are analyzed through both theory and simulation. Then a jointly optimized transceiver scheme based on the signal-to-leakage -and-noise ratio and the signal-to-interference-and-noise ratio is proposed. The simulation results show that the system's average data rate and symbol error rate performances are improved effectively by the proposed scheme.Finally, the downlink pre-coding technology of distributed antenna systems for multi-cell is investigated. A selective coordinated scheme based on the user's location is proposed for multi-cell distributed antenna cooperative systems. And the pre-coding scheme is designed by minimizing the total transmit power of the system while maintaining a target signal-to-interference-and-noise ratio for all users. The simulation results show that a trade-off between the transmit power and the system's information exchange is achieved by the proposed scheme.