Research On Wireless Link Adaptive Technology

Wireless link adaptive technology adjusts the transmitting parameters dynamically, according to the wireless channel changes in time, frequency and space. It is becoming one of the most competitive technologies for next generation wireless communication system, because of its ability to meet various Qos requirements, raise the bandwidth untilization and improve system capability. Firstly, the paper analyzes the fading characters of wireless channel, and researches on the channel estimate and predicting technologies. Meanwhile, based on the classical predicting mode, an improved algorithm is suggested and provided the performance analysis by simulation. Secondly, as the main adaptive technology nowadays, AMC and HARQ are introducted through the basic principles and existing implementation programs. As to AMC, the paper mainly analyzes its adaptive algorithm strategy and the specific error sources, and then improves the former algorithm. As to HARQ, in terms of system throughput and time delay, the paper analyzes its theoretical performance of retransmission mechanism and error frame. Several specific strategies are also introducted which combine different link adaptive technologies. Then, through the system simulation, it is proved that the wireless link adaptive technology shows good capability to enhance the communication system performance. Finally, the paper researches the realization of link adaptive system. And through the software and hardware design of genaral modulation and coding platform, as well as functional testing, it is proved that the wireless link adaptive system is viable.