Fast mutual coupling compensation algorithm for large adaptive antenna array

Abstract

The mutual coupling between antenna array elements degrades the performance of spatial processing algorithm, such as signal-to-interference-plus-noise ratio (SINR) in output of antenna array, antenna gain, and so on. If the mutual coupling matrix (MCM) is known, mutual coupling effect can be mitigated by pre-multiplying the input signal by the inverse of the coupling matrix (assuming that it is invertible). Unfortunately, it requires intensive computational work with the cost of O(N2), where N is a number of antenna elements, especially for large antenna array applications. Taking into account that MCM has the Toeplitz structure, we propose to mitigate the mutual coupling with the cost of O(MlogM) by using fast algorithm that involve circular convolution, where 2N ≤ M < 4N and M is a number of power two. The performance of large adaptive antenna array in the presence of mutual coupling as well as after decoupling is discussed.