Multiuser Scheduling Scheme And Diversity Technique In Broadband Wireless Communication

Technology has developed so fast in last decade and people's requirement also can not compare with ten years ago, wireless communications, and multimedia services, the requirement of wireless communications increases rapidly. The services on wireless communication are changing from text and voice to live broadcast video and image in next generation communication network. However the spectrum resources are not increasing accordingly. If we want higher speed and better service we should improve the spectrum efficiency. Secondly, the signals transmitted in wireless channel are badly polluted because of the wireless channel character. The space-time processing techniques, especially MIMO, as one of core techniques for 4G/B3G systems, can improve system capacity significantly. MIMO technology increases the systems coverage area, at the same time it can also enhance system reliability. At those circumstance we research in the areas of multi-users downlink broadcast channel transmit scheme and multi-users scheduling algorithm.In the research of MIMO downlink broadcast system, we study Multiuser Eigenmode Transmission (MET), is by far the best performing linear transmitter precoding scheme for one-to-multiple-point broadcast channels. It can improve system capacity significantly. In this paper, we analyze the structure of MET and study a low-complexity implementation.For the MIMO downlink broadcast system's resource allocating and users scheduling, we propose a new adaptive scheduling scheme based on proportional fair scheduling algorithm. The base station use MET to eliminate users interference and increase system capacity, at the same time, we use our adaptive proportional fair scheduling algorithm to ensure system's fairness.