Multi-resolution precoding codebook
View Patent ↗Systems and methods are for generating a codebook by: generating a multi-resolution codebook by selecting a common precoder index from a low resolution codebook for a group of adjacent resource blocks (RB)s and for each RB within the group, selecting a high-resolution codebook to fine-tune each RB precoder; and generating feedback for the multi-resolution codebook by quantizing channel state variations.
1. A method implemented in a wireless communications system for generating a codebook, comprising:
having a multi-resolution codebook including codebooks that successively add to the codebook resolution;
using the multi-resolution codebook to perform feedback based precoding by selecting a common precoder index from a low resolution codebook for a group of adjacent resource blocks (RBs);
for each RB within the group, selecting an index from a high-resolution codebook to fine-tune each RB precoder; and
generating feedback based on the multi-resolution codebook by quantizing variations in a wireless channel.
2. The method of claim 1 , wherein the multi-resolution codebook comprises a nested multi-resolution codebook.
3. The method of claim 1 , comprising successively generating the multi-resolution codebook.
4. The method of claim 1 , wherein the multi-resolution codebook generating includes codebook partitioning.
5. The method of claim 1 , wherein the multi-resolution codebook generating includes finding the higher resolution codebooks based on transformation.
6. The method of claim 1 , wherein the wireless channel is correlated in time or frequency.
7. The method of claim 1 , comprising generating an index of a closest precoder as feedback.
8. The method of claim 1 , comprising generating a first level resolution codebook.
9. The method of claim 1 , comprising generating a second level resolution codebook.
10. The method of claim 5 , wherein the transformation includes unitary transformation.
11. The method of claim 9 , wherein the second level resolution codebook comprises a set of precoders in a vicinity of a given precoder on a sphere.
12. The method of claim 9 , wherein the second level resolution codebook is generated by individually optimizing entries of the second level codebook for each precoder in a first level codebook.
13. The method of claim 9 , wherein the second level resolution codebook is generated by obtaining second level codebooks as a transformation of a single codebook.
14. The method of claim 9 , wherein the second level resolution codebook is generated by obtaining second level codebooks as a unitary rotation of an average performance optimization.
15. The method of claim 1 , comprising precoding based on the multi-resolution codebook.
16. A communication system, comprising:
a base station having a processor adapted to use a multi-resolution codebook by selecting a common precoder index from a low resolution codebook for a group of adjacent resource blocks (RBs) and for each RB within the group, and selecting a high-resolution codebook to fine-tune each RB precoder; and
one or more wireless devices generating feedback for the multi-resolution codebook by quantizing state variations in a channel, and communicating with the base station using the multi-resolution codebook.
17. The system of claim 16 , wherein the multi-resolution codebook comprises a nested multi-resolution codebook.
18. The system of claim 16 , wherein the processor successively generates the multi-resolution codebook.
19. The system of claim 16 , wherein the multi-resolution codebook is generated through codebook partitioning.
20. The system of claim 16 , wherein the multi-resolution codebook is generated by performing unitary rotations on the multi-resolution codebook.
21. The system of claim 16 , wherein the channel is correlated in time or frequency.
22. A multi-resolution codebook precoding process, comprising:
generating low resolution codebook(s);
generating high resolution codebook(s) based on the low resolution codebook(s);
determining a common precoder index from the low resolution codebook(s) suitable for all RBs in each group;
for each RB, determining individual indices from the high resolution codebook(s) based on the common precoder index from the low resolution codebook(s);
generating feedback signals by gathering all indices; and
performing precoding at a base station by regenerating a target precoder using the feedback signals.
23. The process of claim 22 , further comprising:
applying the multi-resolution codebook to perform precoding.
24. The process of claim 22 , further comprising:
generating the high resolution codebook(s) by directly optimizing each individual high resolution codebook for each precoder entry in the low resolution codebook.
25. The process of claim 22 , further comprising:
individually optimizing the high resolution codebook(s) by partitioning.
26. The process of claim 22 , further comprising:
jointly optimizing the high resolution codebook(s).