Research On BS Placement In The Wireless City System Based On Particle Swarm Optimization Algorithm

SCDMA(Synchronous Code Division Multiple Access) technology is a completely new technical standard for wireless communications.Because it uses smart antenna,software radio and other advanced technology With independent intellectual property rights.It attaches theoretical and practical value to post-network construction and system optimization by the research of SCDMA base stations'placement.The aim of SCDMA base stations'placement is not only to meet minimum field strength in the target region,but also to meet the quality requirements,business coverage,as well as the reduction of the economic cost.However,these objectives are often conflictive.Thus in the solving process,we should try to balance the various objectives or to find a solution to them.By the concept of sub-particle swarm,it enhances information sharing and reduces the computational cost.Experiment shows that it is more flexible and effective to capture the optimal solution.Particle Swarm Optimization wins great advantage over multi-objective optimization problem.Nevertheless,the diversity of the population is prone to decrease with the passage of time,thus it is easy to fall into local optimal solution.In order to reduce the possibility into the local optimal solution at an early stage,the roulette selection operator often used in the genetic algorithm is introduced in this paper. Experiment shows that through this method "prematurity" is inhibited and convergence speed become faster.When the algorithm is about to converge,most individuals are centralized in the area of local optimal solution or near global optimal solution.In other words," prematurity " has occurred.In order to escape the limitation of individual regions, climbing operator is adopted in this paper,which could strengthen its climbing ability and accelerate the possibility of moving away local optimal solution.Experiment proves that at later stage the introduction of climbing operator avoids the " prematurity" to maximum extent.