Abstract: For QoS multicast routing problem,an improved quantum particle swarm optimization algorithm was proposed.In order to solve the problem better,the algorithm uses the preprocessing mechanism.Firstly,the graphical network topology is converted to the tree network topology.On this basis,the codec of particles can easily be established.It is conducive to eliminating the bad particles and loops,also reduces duplication of the particle.Then the quantum-behaved particle swarm optimization was used to update the position of particles.After updating the position of particles,crossover and selection operator enhancing the diversity of particle populations and accelerating the convergence speed were made for particle populations.Finally,for comparison,the algorithm and the traditional particle swarm optimization algorithm were programmed.Simulation results show that the improved quantum-behaved particle swarm optimization algorithm can not only get better solutions than traditional particle swarm optimization algorithm,but also has faster convergence and global optimization capability.

Key words: Quality of server(QoS),Multicast routing,Preprocessing mechanism,Quantum behavior,Particle swarm optimization(PSO) algorithm