Methods, network node and wireless terminal for beam tracking when beamforming is employed

A network node arranged to support beam tracking in a wireless terminal when beamforming is employed in radio communication between the wireless terminal and the network node using a current selected network beam (Bc) and a current selected terminal beam (Tc), wherein the network node comprises:

• a communication circuit;
• at least one processor operatively coupled to the communication circuit;
• and
• at least one memory storing computer-executable instructions that, when executed by the
• at least one processor, configure the network node to:
• identify a set of candidate network beams (B) having spatial characteristics similar to the current selected network beam (Bc), wherein a beam reference signal is associated with each candidate network beam in the set of candidate network beams (B);
• signal to the wireless terminal identities of the beam reference signals associated with the set of candidate network beams (B) or identities of the candidate network beams;
• and
• transmit the beam reference signals in the set of candidate network beams (B) using beam sweeping where at least some of the beam reference signals are transmitted separately multiple times, thereby enabling the wireless terminal to measure received power of the beam reference signals using different candidate terminal beams (T).

A method performed by a wireless terminal for beam tracking when beamforming is employed in radio communication between the wireless terminal and a network node using a current selected network beam (Bc) and a current selected terminal beam (Tc), the method comprising:

• receiving from the network node identities of beam reference signals associated with a set of candidate network beams (B) or identities of the candidate network beams;
• measuring received power of said beam reference signals using different candidate terminal beams (T);
• and
• estimating received power of combinations of beam reference signal and candidate terminal beam (T) that have not been measured, based on the measured combinations of beam reference signal and candidate terminal beam (T).

A wireless terminal arranged to perform beam tracking when beamforming is employed in radio communication between the wireless terminal and a network node using a current selected network beam (Bc) and a current selected terminal beam (Tc), wherein the wireless terminal comprises:

• a communication circuit;
• at least one processor operatively coupled to the communication circuit;
• and
• at least one memory storing computer-executable instructions that, when executed by the
• at least one processor, configure the wireless terminal to:
• receive from the network node identities of beam reference signals associated with a set of candidate network beams (B) or identities of the candidate network beams;
• measure received power of said beam reference signals using different candidate terminal beams (T);
• and
• estimate received power of combinations of beam reference signal and candidate terminal beam (T) that have not been measured, based on the measured combinations of beam reference signal and candidate terminal beam (T).