A new calibration algorithm for cellular CDMA antenna arrays

We propose an iterative subspace-based calibration algorithm for an asynchronous CDMA-based antenna array in the presence of unknown gain and phase error is presented. The algorithm does not depends on the array geometry and does not require a prior knowledge of the directions of arrival (DOA) of the signals. The method requires the code sequence of a reference user only. The proposed algorithm is based on the subspace method and root finding approach and it provides us with estimates of the calibration vector, the DOA and the channel impulse response, by using the code sequence of a reference user. It is shown that experimental results match well with the theoretical calibration algorithm. Also, we propose an efficient algorithm using the simulated annealing technique. This algorithm overcomes the problem of the initial guessing in the subspace-based approach.