Baseband unit, radio unit and methods in a wireless communications network

A method performed by a Radio Unit, RU, (112) for performing beamforming for a communication between a User Equipment, UE, (120) and a base station (110) in a wireless communications network (100) using a multiple antenna system for communication, wherein the RU (112) is associated with the base station (110), the method comprising:

• receiving (501) from a Base Band Unit, BBU, (111) associated with the base station (110), one or more tap-domain BFWs selected by the BBU (111),
• reconstructing (502) tap-domain BFWs based on the selected one or more tap-domain BFWs,
• transforming (503) by a mathematical transformation, at least some of the reconstructed tap-domain BFWs of the one or more tap-domain BFWs, to obtain corresponding frequency domain BFWs related to respective subcarriers out of a number of subcarriers, and
• performing (505) beamforming with the obtained frequency domain BFWs on the respective subcarriers out of the number of subcarriers for the communication between the UE (120) and the base station (110).

A Baseband Unit, BBU, (111) configured to assist a Radio Unit, RU, (112) to perform beamforming for a communication between a User Equipment, UE, (120) and a base station (110) in a wireless communications network (100) using a multiple antenna system for communication, wherein the BBU (111) and the RU (112) are adapted to be associated with the base station (110), wherein the BBU (111) is further configured to:

• calculate respective Beamforming Weights, BFWs, for at least a subset of subcarriers out of a number of subcarriers,
• transform by a mathematical transformation, the respective calculated BFWs, from frequency domain BFWs to obtain tap-domain BFWs,
• select one or more tap-domain BFWs from said obtained tap-domain BFWs, and
• send to the RU (112), the selected one or more the tap-domain BFWs, which selected one or more tap-domain BFWs is adapted to assist the RU (112) to perform beamforming for the communication between the UE (120) and the base station (110).