Embodiments of the disclosure relate to supporting cooperative transmission in massive multiple-input multiple-output (MIMO) systems, such as a wireless distribution system (WDS). A WDS includes a plurality of remote units each defining a home coverage cell. A selected remote unit can coordinate with a neighboring remote unit(s) to help mitigate inter-cell interference for a selected client device(s) located in an overlapping coverage area between the home coverage cell of the selected remote unit and a neighboring coverage cell(s) defined by the neighboring remote unit(s). The selected remote unit receives channel-data information from the selected client device(s) and forms a first radio frequency (RF) beam based on the channel-data information to distribute a downlink signal(s) to the selected client device. The selected remote unit coordinates with the neighboring remote unit(s) based on the channel-data information to form a second RF beam to distribute the downlink signal(s) to the selected client device.