The Research In Applying Genetic Algorithm To Beamforming Of Antenna Array

Since2009, China formally issued3G licences for operators, The third generationmobile communication technology in our country is developing rapidly, and3G usersbecome new objects for each big operators. In the fierce competition, How tomaintain a high market share, maintain the confidence for user is the operator’sconsideration, which greatly depend on communication network quality. Due to thesmart antenna, application beam-forming technologies significant improvement of thebase station sensitivity and transmission power, it can greatly reduce internal systeminterference and interference between neighboring cells, so that the system capacityhas been expanded. At the same time it can reduced the numbers of the base stationfor the business of high-density demanded such as urban and suburban. How todesign the antenna array beamforming strategy, make antenna array automatic withmaximum gain alignment useful signal reaches direction, and shielding noise andinterfering signal is the essence of smart antenna technology, also be this paper pointof research.This paper start from introducing the research background, and simple illustratesthe third generation mobile communication technology in China, the developmentsituation of smart antenna and the development and research of the current situation.Smart antenna is mainly constituted by the antenna array, d/a change device andbeamforming network. The formation of the antenna array ‘s orientation image is thecore technology for smart antenna, it is to change the number of antenna array, arrayelements position, feeder amplitude and phase, in view of the different signalenvironment system parameter selection of optimization, thereby improving thefrequency resource utilization and communication quality. In practical engineeringapplication, often according to certain set to form an antenna array with the samecraftwork and characteristic antenna element, make the whole reflected radiationproperties specific communication environmental requirements. One dimensionallinear arrays in mobile communication system in the most widely used model. So thistopic is based on the model.Genetic algorithm is a simulated biologic in the natural environment genetic andevolutionary process macro bionic method, according to "survival competition" and"balance principle by selecting, crossover and mutation program and composed of adaptive global optimization probability search algorithm. Because it have a uniquesuperiority in solving large space, parameters and nonlinearity on complex problems,it widely used in many fields. In recent years, the genetic algorithm is applied to theantenna optimized design field gradually.Based on the traditional genetic algorithm deficiency, the paper puts forwardthree measures for improvement:the integer coding, mutation operationsimprovement and cross generation, and from main lobe position, zero trapped positioncontrol and inhibit side-lobe three aspects control antenna array radiation orientationgraph shape to do a detailed study. And separately with the modified geneticalgorithm and traditional genetic algorithm simulation contrast, we found that theimproved genetic algorithm can overcome the deficiency of traditional geneticalgorithm, greatly accelerated the optimal speed and quality, good satisfies our designneeds.