Beamforming signaling in a wireless network
Methods, apparatus, and systems for wireless communications are described. Example methods, devices, and systems are described that utilize a precoding matrix indicator (PMI) computed based at least in part on first signals received via a first cell and on second signals received via a second cell. Information in a measurement information message may be used as part of computing a PMI. The measurement information message may indicate resources of a first cell and a second cell for use in computing the PMI. A wireless device may receive first signals via the first cell and second signals via the second cell based on information in the measurement information message, and may use these signals to compute the PMI. The computed PMI may be used in communications with a base station. For example, the wireless device may receive a packet beamformed employing the computed PMI.
1. A method comprising:
receiving, by a wireless device and from a first node, a measurement information message comprising at least one information element;
receiving, based on the at least one information element, first signals from the first node and second signals from a second node;
transmitting, to the first node, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals received from the first node and the second signals received from the second node; and
receiving, from the first node, at least one data packet beamformed according to a precoding matrix associated with the PMI.
2. The method of claim 1 , wherein the at least one information element indicates at least one of:
one or more resource blocks associated with the first signals; or
one or more resource blocks associated with the second signals.
3. The method of claim 1 , wherein the at least one information element is based, at least in part, on one or more information elements received by the first node from the second node.
4. The method of claim 1 , wherein the PMI is determined further based, at least in part, on at least one of:
a first measurement of the first signals received from the first node and on a second measurement of the second signals received from the second node; or
reducing downlink inter-cell interference received from the second node.
5. The method of claim 1 , wherein the PMI is determined by at least one of:
selecting the PMI from a plurality of predetermined PMIs; or
selecting the PMI from a subset of a precoding codebook indicated by a codebook subset restriction bitmap parameter.
6. The method of claim 1 , wherein:
the first signals are first reference signals associated with the first node; and
the second signals are second reference signals associated with the second node.
7. The method of claim 1 , wherein:
the first signals are associated with a first cell; and
the second signals are associated with a second cell.
8. The method of claim 1 , wherein receiving the first signals comprises receiving the first signals via a downlink carrier of the first node.
9. The method of claim 1 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
10. The method of claim 1 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
11. The method of claim 1 , wherein the first node and the second node correspond to different base stations.
12. A wireless device comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
receive, from a first node, a measurement information message comprising at least one information element;
receive, based on the at least one information element, first signals from the first node and second signals from a second node;
transmit, to the first node, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals received from the first node and the second signals received from the second node; and
receive, from the first node, at least one data packet beamformed according to a precoding matrix associated with the PMI.
13. The wireless device of claim 12 , wherein the PMI is determined by at least one of:
selecting the PMI from a plurality of predetermined PMIs; or
selecting the PMI from a subset of a precoding codebook indicated by a codebook subset restriction bitmap parameter.
14. The wireless device of claim 12 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
15. The wireless device of claim 12 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
16. The wireless device of claim 12 , wherein the first node and the second node correspond to different base stations.
17. A method comprising:
transmitting, by a first node and to a wireless device, a measurement information message indicating first signals associated with the first node and second signals associated with a second node;
receiving, by the first node and from the wireless device, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals associated with the first node and the second signals associated with the second node; and
transmitting, by the first node, at least one data packet beamformed according to a precoding matrix associated with the PMI.
18. The method of claim 17 , wherein the measurement information message indicates at least one of:
one or more resource blocks associated with the first signals; or
one or more resource blocks associated with the second signals.
19. The method of claim 17 , wherein the measurement information message comprises one or more information elements received by the first node from the second node.
20. The method of claim 17 , wherein the PMI is determined further based, at least in part, on at least one of:
a first measurement of the first signals associated with the first node and on a second measurement of the second signals associated with the second node; or
reducing downlink inter-cell interference received from the second node.
21. The method of claim 17 , wherein the PMI is determined by at least one of:
selecting the PMI from a plurality of predetermined PMIs; or
selecting the PMI from a subset of a precoding codebook indicated by a codebook subset restriction bitmap parameter.
22. The method of claim 17 wherein:
the first signals are first reference signals associated with the first node; and
the second signals are second reference signals associated with the second node.
23. The method of claim 17 , wherein:
the first signals are associated with a first cell; and
the second signals are associated with a second cell.
24. The method of claim 17 , further comprising:
transmitting the first signals via a downlink carrier.
25. The method of claim 17 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
26. The method of claim 17 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
27. The method of claim 17 , wherein the first node and the second node correspond to different base stations.
28. A first node comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the first node to:
transmit, to a wireless device, a measurement information message indicating first signals associated with the first node and second signals associated with a second node;
receive, from the wireless device, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals associated with the first node and the second signals associated with the second node; and
transmit at least one data packet beamformed according to a precoding matrix associated with the PMI.
29. The first node of claim 28 , wherein the PMI is determined further based, at least in part, on at least one of:
a first measurement of the first signals received from the first node and on a second measurement of the second signals received from the second node; or
reducing downlink inter-cell interference received from the second node.
30. The first node of claim 28 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
31. The first node of claim 28 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
32. The first node of claim 28 , wherein the first node and the second node correspond to different base stations.
33. A non-transitory computer-readable medium comprising instructions that, when executed, configure a wireless device to:
receive, from a first node, a measurement information message comprising at least one information element;
receive, based on the at least one information element, first signals from the first node and second signals from a second node;
transmit, to the first node, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals received from the first node and the second signals received from the second node; and
receive, from the first node, at least one data packet beamformed according to a precoding matrix associated with the PMI.
34. The non-transitory computer-readable medium of claim 33 , wherein the PMI is determined by at least one of:
selecting the PMI from a plurality of predetermined PMIs; or
selecting the PMI from a subset of a precoding codebook indicated by a codebook subset restriction bitmap parameter.
35. The non-transitory computer-readable medium of claim 33 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
36. The non-transitory computer-readable medium of claim 33 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
37. The non-transitory computer-readable medium of claim 33 , wherein the first node and the second node correspond to different base stations.
38. A non-transitory computer-readable medium comprising instructions that, when executed, configure a first node to:
transmit, to a wireless device, a measurement information message indicating first signals associated with the first node and second signals associated with a second node;
receive, from the wireless device, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals associated with the first node and the second signals associated with the second node; and
transmit at least one data packet beamformed according to a precoding matrix associated with the PMI.
39. The non-transitory computer-readable medium of claim 38 , wherein the PMI is determined further based, at least in part, on at least one of:
a first measurement of the first signals received from the first node and on a second measurement of the second signals received from the second node; or
reducing downlink inter-cell interference received from the second node.
40. The non-transitory computer-readable medium of claim 38 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
41. The non-transitory computer-readable medium of claim 38 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
42. The non-transitory computer-readable medium of claim 38 , wherein the first node and the second node correspond to different base stations.
43. A system comprising:
a wireless device; and
a first node,
wherein the first node is configured to:
transmit, to the wireless device, a measurement information message indicating first signals associated with the first node and second signals associated with a second node; and
wherein the wireless device is configured to:
receive, from a first node, the measurement information message;
receive the first signals and the second signals;
transmit, to the first node, channel state information comprising a precoding matrix indicator (PMI) determined based at least in part on the first signals and the second signals; and
receive, from the first node, at least one data packet beamformed according to a precoding matrix associated with the PMI.
44. The system of claim 43 , wherein the PMI is determined by at least one of:
selecting the PMI from a plurality of predetermined PMIs; or
selecting the PMI from a subset of a precoding codebook indicated by a codebook subset restriction bitmap parameter.
45. The system of claim 43 , wherein the PMI is determined further based, at least in part, on at least one of:
a first measurement of the first signals received from the first node and on a second measurement of the second signals received from the second node; or
reducing downlink inter-cell interference received from the second node.
46. The system of claim 43 , wherein the first node comprises at least one of:
a first base station;
a first relay node; or
a first transceiver.
47. The system of claim 43 , wherein the second node comprises at least one of:
a second base station;
a second relay node; or
a second transceiver.
48. The system of claim 43 , wherein the first node and the second node correspond to different base stations.