Spread Spectrum Code Estimation by Artificial Fish Swarm Algorithm

A new estimation method by the swarm intelligent optimization algorithm is presented to recover the transmitted data bits and code of spread spectrum signal over additive white Gaussian noise channel, while the receiver has no knowledge of the transmitter spreading sequence, only knows the length of spreading sequence. The presented estimation method by Artificial Fish Swarm Algorithm (AFSA) is insensitive to initial values, has a strong robustness, and has the faster convergence speed and better estimation precision than the estimation method by Genetic Algorithm (GA) and the estimation method by Particle Swarm Optimization (PSO). The results show that the method can obtain the optimal or sub-optimal estimation of spreading code, even when the signal power is below the noise power.