Beamforming codeword exchange between base stations
Methods, apparatus, and systems for wireless communications are disclosed. A first base station may be configured to receive, from a second base station, one or more messages. The messages may include downlink beamforming information elements for a downlink cell. Each downlink beamforming information element of the plurality of downlink beamforming information elements may be associated with a respective resource block of a plurality of resource blocks in the downlink cell. The first base station may select a first beamforming codeword for at least one resource block of the plurality of resource blocks based on the downlink beamforming information associated with the at least one resource block. The first base station may transmit, to a wireless device, signals on the at least one resource block employing the first beamforming codeword.
1. A first base station configured to communicate with a wireless device, the 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 a plurality of downlink beamforming information elements for a downlink cell, wherein each downlink beamforming information element of the plurality of downlink beamforming information elements is associated with a respective resource block of a plurality of resource blocks in the downlink cell and indicates a parameter for beamforming for the respective resource block;
select, for at least one resource block of the plurality of resource blocks, a first beamforming codeword based at least in part on at least one first downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one first downlink beamforming information element is associated with the at least one resource block; and
transmit, to the wireless device, signals on the at least one resource block employing the first beamforming codeword.
2. The first base station of claim 1 , wherein each downlink beamforming information element of the plurality of downlink beamforming information elements indicates a beamforming codeword for the respective resource block.
3. The first base station of claim 1 , wherein the plurality of downlink beamforming information elements indicates a second beamforming codeword associated with a second resource block of the plurality of resource blocks and indicates a third beamforming codeword associated with a third resource block of the plurality of resource blocks.
4. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, cause the first base station to:
select, for at least one other resource block of the plurality of resource blocks, a second beamforming codeword based at least in part on at least one second downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one second downlink beamforming information element is associated with the at least one other resource block; and
transmit, to the wireless device, signals on the at least one other resource block employing the second beamforming codeword.
5. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, cause the first base station to select the first beamforming codeword based on reducing inter-cell interference from the second base station.
6. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, further cause the first base station to compute inter-cell interference to the second base station based on information received from the wireless device.
7. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, cause the first base station to select the first beamforming codeword based on a zero-forcing criterion.
8. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, cause the first base station to select the first beamforming codeword based on a minimum mean squared error criterion.
9. The first base station of claim 1 , wherein the instructions, when executed by the one or more processors, cause the first base station to select the first beamforming codeword based on a maximum signal to leakage ratio criterion.
10. A method for use in a first base station configured to communicate with a wireless device, the method comprising:
receiving, by the first base station and from a second base station, at least one message comprising a plurality of downlink beamforming information elements for a downlink cell, wherein each downlink beamforming information element of the plurality of downlink beamforming information elements is associated with a respective resource block of a plurality of resource blocks in the downlink cell and indicates a parameter for beamforming for the respective resource block;
selecting, for at least one resource block of the plurality of resource blocks, a first beamforming codeword based at least in part on at least one first downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one first downlink beamforming information element is associated with the at least one resource block; and
transmit, by the first base stations and to the wireless device, signals on the at least one resource block employing the first beamforming codeword.
11. The method of claim 10 , wherein each downlink beamforming information element of the plurality of downlink beamforming information elements indicates a beamforming codeword for the respective resource block.
12. The method of claim 10 , wherein the plurality of downlink beamforming information elements indicates a second beamforming codeword associated with a second resource block of the plurality of resource blocks and indicates a third beamforming codeword associated with a third resource block of the plurality of resource blocks.
13. The method of claim 10 , further comprising:
selecting, for at least one other resource block of the plurality of resource blocks, a second beamforming codeword based at least in part on at least one second downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one second downlink beamforming information element is associated with the at least one other resource block; and
transmitting, by the first base station and to the wireless device, signals on the at least one other resource block employing the second beamforming codeword.
14. The method of claim 10 , wherein selecting the first beamforming codeword is based on reducing inter-cell interference from the second base station.
15. The method of claim 10 , further comprising:
computing inter-cell interference to the second base station based on information received from the wireless device.
16. The method of claim 10 , wherein selecting the first beamforming codeword is based on a zero-forcing criterion.
17. The method of claim 10 , wherein selecting the first beamforming codeword is based on a minimum mean squared error criterion.
18. The method of claim 10 , wherein selecting the first beamforming codeword is based on a maximum signal to leakage ratio criterion.
19. A system comprising:
a wireless device configured to receive signals from a first base station;
the first base station, wherein the first base station is configured to:
receive, from a second base station, at least one message comprising a plurality of downlink beamforming information elements for a downlink cell, wherein each downlink beamforming information element of the plurality of downlink beamforming information elements is associated with a respective resource block of a plurality of resource blocks in the downlink cell and indicates a parameter for beamforming for the respective resource block;
select, for at least one resource block of the plurality of resource blocks, a first beamforming codeword based at least in part on at least one first downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one first downlink beamforming information element is associated with the at least one resource block; and
transmit, to the wireless device, signals on the at least one resource block employing the first beamforming codeword; and
the second base station, wherein the second base station is configured to:
transmit, to the first base station, the at least one message comprising the plurality of downlink beamforming information elements for the downlink cell.
20. The system of claim 19 , wherein each downlink beamforming information element of the plurality of downlink beamforming information elements indicates a beamforming codeword for the respective resource block.
21. The system of claim 19 , wherein the plurality of downlink beamforming information elements indicates a second beamforming codeword associated with a second resource block of the plurality of resource blocks and indicates a third beamforming codeword associated with a third resource block of the plurality of resource blocks.
22. The system of claim 19 , wherein the first base station is further configured to:
select, for at least one other resource block of the plurality of resource blocks, a second beamforming codeword based at least in part on at least one second downlink beamforming information element of the plurality of downlink beamforming information elements, wherein the at least one second downlink beamforming information element is associated with the at least one other resource block; and
transmit, to the wireless device, signals on the at least one other resource block employing the second beamforming codeword.
23. The system of claim 19 , wherein the first base station is further configured to select the first beamforming codeword based on reducing inter-cell interference from the second base station.
24. The system of claim 19 , wherein:
the wireless device is configured to transmit interference information to the first base station; and
the first base station is configured to compute inter-cell interference to the second base station based on the interference information received from the wireless device.
25. The system of claim 19 , wherein the first base station is configured to select the first beamforming codeword based on a zero-forcing criterion.
26. The system of claim 19 , wherein the first base station is configured to select the first beamforming codeword based on a minimum mean squared error criterion.
27. The system of claim 19 , wherein the first base station is configured to select the first beamforming codeword based on a maximum signal to leakage ratio criterion.