A network node includes an antenna array having a plurality of antenna sub-arrays. A switching device is coupled to the antenna array, the switching device being configured to connect at least two input signals to respective ones of the plurality of antenna sub-arrays. A processor is configured to determine a channel capacity, wherein based on the channel capacity, the processor is configured to control the switching device to switch a connection of the at least two input signals to different ones of the plurality of antenna sub-arrays to change one or more of an inter-distance between the respective ones of the plurality of antenna sub-arrays and a down-tilting angle of the antenna array.