Beam forming method, apparatus and system

1. A method comprising:

retrieving an uplink allocation of a user equipment from a downlink control signal;

receiving from a user equipment an uplink signal using multiple narrow antenna beams;

measuring beam-specific pilot signal powers from the user equipment uplink signal for all the beams;

using the measured pilot signal powers to determine, in a remote radio unit, which one or ones of the downlink narrow beams is to be used for a downlink signal for the user equipment;

transmitting and receiving a baseband signal via a first set of antenna ports; and

transmitting and receiving a radio frequency signal via a second set of antenna ports comprising more ports than the first set of ports.

2. A method according to claim 1 , further comprising realizing a beamforming function as an analogue beamforming unit in the remote radio unit.

3. A method according to claim 1 , further comprising realizing a downlink beam selection functionality in the remote radio unit.

4. A method according to claim 1 , further comprising allocating different downlink bursts to different antenna beams.

5. A method according to claim 1 , further comprising transmitting a preamble signal and a MAP information signal in the downlink transmission via all antenna beams using cyclic delay diversity method.

6. A method according to claim 1 , further comprising measuring the pilot signal power from the uplink transmission in response to uplink MAP information transmitted in the downlink transmission.

7. A method according to claim 1 , further comprising selecting one or two antenna beams with the largest uplink pilot signal power for the downlink transmission for each user equipment.

8. A multi-antenna beam forming base station, configured to:

retrieve an uplink allocation of a user equipment from a downlink control signal;

receive from a user equipment an uplink signal using multiple narrow antenna beams;

measure beam-specific pilot signal powers from the user uplink signal for all the beams;

use the measured pilot signal powers to determine, in a remote radio unit, which one or ones of the downlink narrow beams is to be used for a downlink signal for the user equipment;

transmit and receive a baseband signal via a first set of antenna ports; and

transmit and receive a radio frequency signal via a second set of antenna ports comprising more ports than the first set of ports.

9. A communications system comprising:

at least one user equipment for enabling a user to access different network services;

a remote radio head unit configured for:

retrieving an uplink allocation of a user equipment from a downlink control signal;

receiving an uplink control information from the base station base band unit;

receiving from the user equipment an uplink signal using multiple narrow antenna beams;

measuring beam-specific pilot signal powers from the user uplink signal for all the beams;

using the measured pilot signal powers to determine, in a remote radio unit, which one or ones of the downlink narrow beams is to be used for a downlink signal for the user equipment;

transmitting and receiving a baseband signal via a first set of antenna ports; and

transmitting and receiving a radio frequency signal via a second set of antenna ports comprising more ports than the first set of ports; and

a base station unit for managing radio transmission to the user equipment and radio reception from the user equipment.

10. A non-transitory computer-readable medium comprising instructions that, when executed by a processing device, cause the processing device to perform operations comprising:

retrieving an uplink allocation of a user equipment from a downlink control signal;

receiving from a user equipment an uplink signal using multiple narrow antenna beams;

measuring beam-specific pilot signal powers from the user equipment uplink signal for all the beams;

using the measured pilot signal powers to determine, in a remote radio unit, which one or ones of the downlink narrow beams is to be used for a downlink signal for the user equipment;

transmitting and receiving a baseband signal via a first set of ports; and

transmitting and receiving a radio frequency signal via a second set of ports containing more ports than the first set of ports.

11. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising realizing a beamforming function as an analogue beamforming unit in the remote radio unit.

12. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising realizing a downlink beam selection functionality in the remote radio unit.

13. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising allocating a different downlink bursts to different antenna beams.

14. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising transmitting a preamble signal and a MAP information signal in the downlink transmission via all antenna beams using cyclic delay diversity method.

15. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising measuring the pilot signal power from the uplink transmission in response to uplink MAP information transmitted in the downlink transmission.

16. A non-transitory computer-readable medium according to claim 10 , wherein the computer-readable medium comprises instructions that, when executed by the processing device, further cause the processing device to perform operations comprising selecting one or two antenna beams with the largest uplink pilot signal power for the downlink transmission for each user equipment.