The Research Of Adaptive Algorithm In Smart Antenna And Its Implementation Based On DSP

The channel of wireless mobile communication is a multi-access and multi-user channel, and it has some problems, such as, multi-path fading, time delay spreading, frequency spreading. At present, conventional technologies, which include channel coding, equalization, diversity etc, have become mature, but they can't solve the problems. Smart antenna and space filtering have brought new ideas to the solution of the problems, and smart antenna is considered as the last border of wireless communication technology. It adjusts the weight vectors in order to optimize the main beam and zero sinking of directional pattern real-time and automatically according to maximize exporting criterion. Through optimizing the main beams of expecting user and releasing zero sinking for interfering signals, smart antennas can raise the capacity and performance of system. Select any criterion for using, does not have meaning of the decision. However, choose which kind of algorithm to control how to adjust the directional pattern very important direction beam, because these algorithms determine temporarily attitude respond speed and reduce the complexities of circuit. It is the core of smart antenna processing.The author is participating in the project supported by the scientific and technological drawing room of Hunan Province, and has carried on deep theoretical research and practice to the smart antenna system. This paper has introduced the concept and structure of the smart antenna system. The adaptive algorithm, core to the smart antenna, has been further investigated and numerical emulation. On the basis of discussing the adaptive algorithm of the tradition, I further investigate a kind of adaptive algorithm BLF( Based on Lagrange Formula) which is suitable for CDMA,modify it to be suitable for WCDMA, and probe into at the influences of the algorithm on antennas intercoupling. At last, this paper discusses the implementation of modified BLF based on DSP, proposes the idea of the adaptive algorithm tests platform.