Efficient scheduling of terminal devices
There is provided mechanisms for scheduling communication with terminal devices. A method is performed by a network node. The method comprises receiving, in response to having performed a beam management procedure involving transmission of reference signals in a set of beams, a beam report from each of the terminal devices. Each beam report indicates one of the beams as top ranked. The method comprises scheduling communication for the terminal devices in beams of the set of beams. At least a first terminal device of the terminal devices and a second terminal device of the terminal devices are both scheduled in a first beam of the beams not indicated as top ranked in the beam report of the second terminal device.
1. A method for scheduling communication with terminal devices, the method being performed by a network node, the method comprising:
receiving, in response to having performed a beam management procedure involving transmission of reference signals in a set of beams including a first beam and a second beam, a first beam report from a first terminal device and a second beam report from a second terminal device, the first beam report indicating the first beam as being top ranked by the first terminal device and the second beam report indicating the second beam as being ranked by the second terminal device higher than the first beam;
obtaining information indicating an estimated performance difference associated with a beam pair consisting of the first beam and the second beam, wherein the estimated performance difference is based on a difference between an estimated performance associated with the first beam and an estimated performance associated with the second beam;
determining whether to schedule communication for the second terminal device in the first beam based on the information indicating the estimated performance difference; and
scheduling communication for the terminal devices in beams of the set of beams, wherein the first terminal device and the second terminal device are both scheduled in the first beam.
2. The method of claim 1 , wherein
the second beam report indicates that the second beam is top ranked.
3. The method of claim 1 , wherein
the second beam report indicates that the second beam is top ranked, and
the estimated performance difference is an estimated drop in antenna gain.
4. The method of claim 3 , wherein the determining comprises:
determining to schedule communication for the second terminal device in the first beam as a result of determining that the estimated drop in antenna gain is not larger than a threshold value.
5. The method of claim 1 , wherein
the estimated performance difference is an estimated difference in link budget or an estimated difference in throughput, and
the determining comprises determining to schedule communication for the second terminal device in the first beam as a result of determining that the estimated performance difference is not larger than a threshold value.
6. The method of claim 1 , wherein the method further comprises determining the estimated performance associated with the first beam based on reporting from the second terminal device of a reference signal in the first beam.
7. The method of claim 1 , wherein the communication is scheduled to, in the first beam, use frequency multiplexed communication for at least the first terminal device and the second terminal device.
8. The method of claim 1 , wherein the method further comprises:
transmitting, before communicating data with at least the first terminal device and the second terminal device in the first beam, information of in which of the beams the terminal devices are scheduled.
9. The method of claim 8 , wherein the information is transmitted by signaling of a Transmission Configuration Indicator (TCI) state.
10. The method of claim 9 , wherein the network node configures each of the terminal devices to simultaneously have more than one active TCI state.
11. The method of claim 10 , wherein the terminal devices are by the network node configured with active TCI states that take maximum drop in antenna gain between the beams in the set of beams into account.
12. The method of claim 10 , wherein each TCI state corresponds to one of the beams in the set of beams or, when the beam management procedure further involves transmission of other reference signals in another set of beams, to one beam in the further set of beams.
13. The method of claim 12 , wherein the beams in said another set of beams are wider than the beams in the set of beams.
14. The method of claim 1 , wherein
the second beam report indicates that the second beam is top ranked, and
the second beam corresponds to that beam in the set of beams in which one of the reference signals was by the second terminal device received with highest received power or signal to interference plus noise ratio.
15. The method of claim 1 , wherein the beams in the set of beams are generated by means of analog beamforming wherein, per time instant, only one of the beams is active for communicating with the terminal devices.
16. The method of claim 1 , wherein
the estimated performance difference is an estimated difference in antenna gain, an estimated difference in link budget, or an estimated difference in throughput, and
the estimated performance difference is equal to the difference between the estimated performance associated with the first beam and the estimated performance associated with the second beam.
17. A network node for scheduling communication with terminal devices, the network node comprising processing circuitry, the processing circuitry being configured to cause the network node to:
receive, in response to having performed a beam management procedure involving transmission of reference signals in a set of beams including a first beam and a second beam, a first beam report from a first terminal device and a second beam report from a second terminal device, the first beam report indicating the first beam as being top ranked by the first terminal device and the second beam report indicating the second beam as being ranked by the second terminal device higher than the first beam;
obtain information indicating an estimated performance difference associated with a beam pair consisting of the first beam and the second beam, wherein the estimated performance difference is equal to or based on a difference between an estimated performance associated with the first beam and an estimated performance associated with the second beam;
determine whether to schedule communication for the second terminal device in the first beam based on the information indicating the estimated performance difference; and
schedule communication for the terminal devices in beams of the set of beams, wherein the first terminal device and the second terminal device are both scheduled in the first beam.
18. A non-transitory computer readable storage medium storing a computer program for scheduling communication with terminal devices, the computer program comprising computer code which, when run on processing circuitry of a network node, causes the network node to:
receive, in response to having performed a beam management procedure involving transmission of reference signals in a set of beams including a first beam and a second beam, a first beam report from a first terminal device and a second beam report from a second terminal device, the first beam report indicating the first beam as being top ranked by the first terminal device and the second beam report indicating the second beam as being ranked by the second terminal device higher than the first beam;
obtain information indicating an estimated performance difference associated with a beam pair consisting of the first beam and the second beam, wherein the estimated performance difference is equal to or based on a difference between an estimated performance associated with the first beam and an estimated performance associated with the second beam;
determine whether to schedule communication for the second terminal device in the first beam based on the information indicating the estimated performance difference; and
schedule communication for the terminal devices in beams of the set of beams, wherein the first terminal device and the second terminal device are both scheduled in the first beam.