Beam information exchange between base stations
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 for use in a first base station, the method comprising:
receiving, by the first base station and from a second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station; and
transmitting, by the first base station and to at least one wireless device, at least one signal employing one or more first beamforming codewords selected, by the first base station, based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station.
2. The method of claim 1 , further comprising:
receiving, by the first base station and from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords.
3. The method of claim 2 , 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
4. The method of claim 2 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
5. The method of claim 1 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
6. The method of claim 5 , wherein each codeword 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 base station.
7. The method of claim 6 , wherein the one or more first beamforming codewords are selected based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
8. The method of claim 1 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
9. The method of claim 8 , further comprising determining inter-cell interference based on information received from the at least one wireless device.
10. A first base station comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the first base station to:
receive, from a second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station; and
transmit, to at least one wireless device, at least one signal employing one or more first beamforming codewords selected, by the first base station, based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station.
11. The first base station of claim 10 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
receive, from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords.
12. The first base station 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
13. The first base station of claim 11 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
14. The first base station of claim 10 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
15. The first base station of claim 14 , wherein each codeword 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 base station.
16. The first base station of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
select the one or more first beamforming codewords based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
17. The first base station of claim 10 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
18. The first base station of claim 17 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
determine inter-cell interference based on information received from the at least one wireless device.
19. A method for use in a first base station, the method comprising:
receiving, by the first base station and from a second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station;
selecting, by the first base station, one or more first beamforming codewords based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station; and
transmitting, by the first base station and to at least one wireless device, at least one signal employing the selected one or more first beamforming codewords.
20. The method of claim 19 , further comprising:
receiving, by the first base station and from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords associated with the second base station.
21. The method of claim 20 , 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
22. The method of claim 20 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
23. The method of claim 19 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
24. The method of claim 23 , wherein each codeword 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 base station.
25. The method of claim 24 , wherein the one or more first beamforming codewords are selected based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
26. The method of claim 19 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
27. The method of claim 26 , further comprising determining inter-cell interference based on information received from the at least one wireless device.
28. A first base station comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the first base station to:
receive, from a second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station;
select one or more first beamforming codewords based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station; and
transmit, to at least one wireless device, at least one signal employing the selected one or more first beamforming codewords.
29. The first base station of claim 28 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
receive, from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords.
30. The first base station of claim 29 , 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
31. The first base station of claim 29 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
32. The first base station of claim 28 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
33. The first base station of claim 32 , wherein each codeword 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 base station.
34. The first base station of claim 33 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
select the one or more first beamforming codewords based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
35. The first base station of claim 28 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
36. The first base station of claim 35 , wherein the instructions, when executed by the one or more processors, further cause the first base station to:
determine inter-cell interference based on information received from the at least one wireless device.
37. A non-transitory computer readable medium comprising instructions that, when executed, configure a first base station to:
receive, from a second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station; and
transmit, to at least one wireless device, at least one signal employing one or more first beamforming codewords selected, by the first base station, based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station.
38. The non-transitory computer readable medium of claim 37 , wherein the instructions, when executed, configure the first base station to:
receive, from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords.
39. The non-transitory computer readable medium of claim 38 , 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
40. The non-transitory computer readable medium of claim 38 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
41. The non-transitory computer readable medium of claim 37 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
42. The non-transitory computer readable medium of claim 41 , wherein each codeword 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 base station.
43. The non-transitory computer readable medium of claim 42 , wherein the one or more first beamforming codewords are selected based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
44. The non-transitory computer readable medium of claim 37 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
45. The non-transitory computer readable medium of claim 37 , wherein the instructions, when executed, configure the first base station to determine inter-cell interference based on information received from the at least one wireless device.
46. A system comprising:
a first base station; and
a second base station,
wherein the first base station is configured to:
receive, from the second base station, at least one message comprising at least one index associated with a subset of beamforming codewords of a plurality of beamforming codewords associated with the second base station; and
transmit, to at least one wireless device, at least one signal employing one or more first beamforming codewords selected, by the first base station, based, at least in part, on the at least one index associated with the subset of beamforming codewords of the plurality of beamforming codewords associated with the second base station; and
wherein the second base station is configured to:
transmit, to the first base station, the at least one message.
47. The system of claim 46 , wherein the first base station is configured to:
receive, from the second base station, an indication of a second beamforming codebook, associated with the second base station, comprising the plurality of beamforming codewords.
48. The system of claim 47 , 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 base station, and
the second number of transmit antennas associated with the second base station is different from a first number of transmit antennas associated with the first base station.
49. The system of claim 47 , wherein the at least one index indicates at least one beamforming codeword of the second beamforming codebook.
50. The system of claim 46 , wherein the one or more first beamforming codewords are selected from a first beamforming codebook, associated with the first base station, comprising a second plurality of beamforming codewords.
51. The system of claim 50 , wherein each codeword 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 base station.
52. The system of claim 51 , wherein the one or more first beamforming codewords are selected based on a subset of the transmit antennas associated with the first base station and based on a corresponding subset of rows or columns of one or more codewords in the first beamforming codebook.
53. The system of claim 46 , wherein the one or more first beamforming codewords are selected to reduce inter-cell interference.
54. The system of claim 46 , wherein the first base station is configured to determine inter-cell interference based on information received from the at least one wireless device.