Beamforming in wireless communications
Aspects described herein relate to wireless communications. According to some aspects, a first base station may coordinate with a second base station to select beamforming codewords. The first base station may receive an index indicating beamforming codewords used by a second base station. The first base station may select a beamforming codeword for use in transmitting signals to a wireless device based on the beamforming codeword indicated by the second base station.
1. A method comprising:
receiving, by a first transmission point and from a second transmission point, an indication of a second beamforming codebook, associated with the second transmission point, comprising a plurality of beamforming codewords;
receiving, by the first transmission point and from the second transmission point, at least one message indicating at least one index associated with a subset of beamforming codewords of the plurality of beamforming codewords associated with the second transmission point; and
transmitting, by the first transmission point and to at least one wireless device, at least one signal using one or more first beamforming codewords selected, by the first transmission point, based on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second transmission point.
2. The method of claim 1 , wherein:
each codeword in the second beamforming codebook comprises a second number of rows or columns equal to a second number of transmit antennas associated with the second transmission point, and
the second number of transmit antennas associated with the second transmission point is different from a first number of transmit antennas associated with the first transmission point.
3. The method of claim 1 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
4. The method of claim 1 , further comprising selecting the one or more first beamforming codewords from a first beamforming codebook, associated with the first transmission point, comprising a second plurality of beamforming codewords.
5. The method of claim 4 , wherein each codeword, of the second plurality of beamforming codewords, in the first beamforming codebook, comprises a first number of rows or columns equal to a first number of transmit antennas associated with the first transmission point.
6. The method of claim 5 , wherein the selecting is based on:
a subset of the transmit antennas associated with the first transmission point; and
a corresponding subset of rows or columns of one or more codewords, of the second plurality of beamforming codewords in the first beamforming codebook.
7. The method of claim 1 , wherein the selection of the one or more first beamforming codewords is based on a determination that the one or more first beamforming codewords reduces inter-cell interference.
8. The method of claim 1 , further comprising determining inter-cell interference based on information received from the at least one wireless device.
9. The method of claim 1 , wherein the first transmission point and the second transmission point are included in a same base station.
10. The method of claim 1 , further comprising:
selecting the one or more first beamforming codewords based on a subset of transmit antennas associated with the first transmission point and based on a corresponding subset of rows or columns of one or more codewords in the second beamforming codebook.
11. An apparatus comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the apparatus to:
receive, from a second transmission point, an indication of a second beamforming codebook, associated with the second transmission point, comprising a plurality of beamforming codewords;
receive, from the second transmission point, at least one message indicating at least one index associated with a subset of beamforming codewords of Hall the plurality of beamforming codewords associated with the second transmission point; and
transmit, to at least one wireless device, at least one signal using one or more first beamforming codewords selected, by a first transmission point, based on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second transmission point.
12. The apparatus of claim 11 , wherein:
each codeword in the second beamforming codebook comprises a second number of rows or columns equal to a second number of transmit antennas associated with the second transmission point, and
the second number of transmit antennas associated with the second transmission point is different from a first number of transmit antennas associated with the first transmission point.
13. The apparatus of claim 11 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
14. The apparatus of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the apparatus to select the one or more first beamforming codewords from a first beamforming codebook, associated with the first transmission point, comprising a second plurality of beamforming codewords.
15. The apparatus of claim 14 , wherein each codeword, of the second plurality of beamforming codewords, in the first beamforming codebook, comprises a first number of rows or columns equal to a first number of transmit antennas associated with the first transmission point.
16. The apparatus of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the apparatus to select the one or more first beamforming codewords based on:
a subset of the transmit antennas associated with the first transmission point; and
a corresponding subset of rows or columns of one or more codewords, of the second plurality of beamforming codewords in the first beamforming codebook.
17. The apparatus of claim 11 , wherein the selection of the one or more first beamforming codewords is based on a determination that the one or more first beamforming codewords reduces inter-cell interference.
18. The apparatus of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the apparatus to:
determine inter-cell interference based on information received from the at least one wireless device.
19. The apparatus of claim 11 , wherein the first transmission point and the second transmission point are included in a same base station.
20. The apparatus of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the apparatus to select the one or more first beamforming codewords based on a subset of transmit antennas associated with the first transmission point and based on a corresponding subset of rows or columns of one or more codewords in the second beamforming codebook.
21. A non-transitory computer readable medium comprising instructions that, when executed, configure a first transmission point to:
receive, from a second transmission point, an indication of a second beamforming codebook, associated with the second transmission point, comprising a plurality of beamforming codewords;
receive, from the second transmission point, at least one message indicating at least one index associated with a subset of beamforming codewords of the plurality of beamforming codewords associated with the second transmission point; and
transmit, to at least one wireless device, at least one signal using one or more first beamforming codewords selected, by the first transmission point, based, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second transmission point.
22. The non-transitory computer readable medium of claim 21 , wherein:
each codeword in the second beamforming codebook comprises a second number of rows or columns equal to a second number of transmit antennas associated with the second transmission point, and
the second number of transmit antennas associated with the second transmission point is different from a first number of transmit antennas associated with the first transmission point.
23. The non-transitory computer readable medium of claim 21 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
24. The non-transitory computer readable medium of claim 21 , wherein the instructions, when executed, configure the first transmission point to select one or more first beamforming codewords from a first beamforming codebook, associated with the first transmission point, comprising a second plurality of beamforming codewords.
25. The non-transitory computer readable medium of claim 24 , wherein each codeword, of the second plurality of beamforming codewords, in the first beamforming codebook, comprises a first number of rows or columns equal to a first number of transmit antennas associated with the first transmission point.
26. The non-transitory computer readable medium of claim 25 , wherein selecting is based on:
a subset of the transmit antennas associated with the first transmission point; and
a corresponding subset of rows or columns of one or more codewords, of the second plurality of beamforming codewords in the first beamforming codebook.
27. The non-transitory computer readable medium of claim 21 , wherein the selection of the one or more first beamforming codewords is based on a determination that the one or more first beamforming codewords reduces inter-cell interference.
28. The non-transitory computer readable medium of claim 21 , wherein the instructions, when executed, configure the first transmission point to determine inter-cell interference based on information received from the at least one wireless device.
29. The non-transitory computer readable medium of claim 21 , wherein the first transmission point and the second transmission point are included in a same base station.
30. The non-transitory computer readable medium of claim 21 , wherein the instructions, when executed, configure the first transmission point to select the one or more first beamforming codewords based on a subset of transmit antennas associated with the first transmission point and based on a corresponding subset of rows or columns of one or more codewords in the second beamforming codebook.
31. A system comprising:
a first transmission point; and
a second transmission point,
wherein the first transmission point is configured to:
transmit, to at least one wireless device, at least one signal using one or more first beamforming codewords selected, by the first transmission point, based on at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second transmission point; and
wherein the second transmission point is configured to:
transmit, to the first transmission point, at least one message indicating the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords.
32. The system of claim 31 , wherein the second transmission point is configured to:
transmit, to the first transmission point, an indication of a second beamforming codebook, associated with the second transmission point, comprising the plurality of beamforming codewords.
33. The system of claim 32 , wherein:
each codeword in the second beamforming codebook comprises a second number of rows or columns equal to a second number of transmit antennas associated with the second transmission point, and
the second number of transmit antennas associated with the second transmission point is different from a first number of transmit antennas associated with the first transmission point.
34. The system of claim 32 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
35. The system of claim 31 , wherein the first transmission point is configured to select the one or more first beamforming codewords from a first beamforming codebook, associated with the first transmission point, comprising a second plurality of beamforming codewords.
36. The system of claim 35 , wherein each codeword, of the second plurality of beamforming codewords, in the first beamforming codebook, comprises a first number of rows or columns equal to a first number of transmit antennas associated with the first transmission point.
37. The system of claim 36 , wherein the one or more first beamforming codewords are selected based on:
a subset of the transmit antennas associated with the first transmission point; and
a corresponding subset of rows or columns of one or more codewords, of the second plurality of beamforming codewords in the first beamforming codebook.
38. The system of claim 31 , wherein the selection of the one or more first beamforming codewords is based on a determination that the one or more first beamforming codewords reduces inter-cell interference.
39. The system of claim 31 , wherein the first transmission point is configured to determine inter-cell interference based on information received from the at least one wireless device.
40. The system of claim 31 , further comprises a base station comprising the first transmission point and the second transmission point.