A method is provided for channel estimation of an antenna array comprising multiple antenna elements. The method comprises obtaining channel state information for antenna elements with a high-end radio frequency chain, wherein the antenna elements with the high-end radio frequency chain are placed in the antenna array intermittently with antenna elements with a low-cost radio frequency chain. Channel state information is estimated for the antenna elements with the low-cost radio frequency chain, by interpolating the channel state information obtained for the antenna elements with the high-end radio frequency chain.