Multi-resolution precoding codebook

Abstract

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.

What is claimed is: 
     
         1 . A base station used in a wireless communications system for precoding data, the base station comprising:
 a receiving unit to receive from a user equipment a low resolution precoder index for a group of resource blocks (RBs) and a high resolution precoder index for one or more resource blocks within the group of RBs; and   a determining unit to determine a precoder using a multi-resolution codebook according to the low resolution precoder index and the high resolution precoder index.   
     
     
         2 . The base station as in  claim 1 , wherein a channel for the group of RBs is correlated in time or in frequency. 
     
     
         3 . The base station as in  claim 1 , wherein the channel for the group of RBs is correlated in frequency across different OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         4 . The base station as in  claim 1 , wherein the group of RBs are adjacent in time or in frequency. 
     
     
         5 . The base station as in  claim 4 , wherein the group of RBs are adjacent in frequency over OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         6 . The base station as in  claim 1 , wherein the multi-resolution codebook consists of two resolution levels of a first level and a second level. 
     
     
         7 . A user equipment used in a wireless communications system for precoding data, the user equipment comprising:
 a transmission unit to transmit to a base station a low resolution precoder index for a group of resource blocks (RBs) and a high resolution precoder index for one or more resource blocks within the group of RBs; and   a receiving unit to receive data precoded with a precoder from the base station,   wherein the precoder is determined using a multi-resolution codebook according to the low resolution precoder index and the high resolution precoder index.   
     
     
         8 . The user equipment as in  claim 7 , wherein a channel for the group of RBs is correlated in time or in frequency. 
     
     
         9 . The user equipment as in  claim 7 , wherein the channel for the group of RBs is correlated in frequency across different OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         10 . The user equipment as in  claim 7 , wherein the group of RBs are adjacent in time or in frequency. 
     
     
         11 . The user equipment as in  claim 10 , wherein the group of RBs are adjacent in frequency over OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         12 . The user equipment as in  claim 7 , wherein the multi-resolution codebook consists of two resolution levels of a first level and a second level. 
     
     
         13 . A user equipment used in a wireless communications system for precoding data, the user equipment comprising:
 a transmission unit to transmit to a base station a low resolution precoder index for a group of resource blocks (RBs) and a high resolution precoder index for one or more resource blocks within the group of RBs,   wherein the base station determines a precoder using a multi-resolution codebook according to the low resolution precoder index and the high resolution precoder index.   
     
     
         14 . The user equipment as in  claim 13 , wherein a channel for the group of RBs is correlated in time or in frequency. 
     
     
         15 . The user equipment as in  claim 13 , wherein the channel for the group of RBs is correlated in frequency across different OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         16 . The user equipment as in  claim 13 , wherein the group of RBs are adjacent in time or in frequency. 
     
     
         17 . The user equipment as in  claim 16 , wherein the group of RBs are adjacent in frequency over OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         18 . The user equipment as in  claim 13 , wherein the multi-resolution codebook consists of two resolution levels of a first level and a second level. 
     
     
         19 . A user equipment used in a wireless communications system for precoding data, the user equipment comprising:
 a receiving unit to receive data precoded with a precoder from a base station,   wherein the precoder is determined using a multi-resolution codebook according to a high resolution precoder index for one or more resource blocks within a group of resource blocks (RBs) and a low resolution precoder index for the group of RBs.   
     
     
         20 . The user equipment as in  claim 19 , wherein a channel for the group of RBs is correlated in time or in frequency. 
     
     
         21 . The user equipment as in  claim 19 , wherein the channel for the group of RBs is correlated in frequency across different OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         22 . The user equipment as in  claim 19 , wherein the group of RBs are adjacent in time or in frequency. 
     
     
         23 . The user equipment as in  claim 22 , wherein the group of RBs are adjacent in frequency over OFDM (orthogonal frequency-division multiplexing) tones. 
     
     
         24 . The user equipment as in  claim 19 , wherein the multi-resolution codebook consists of two resolution levels of a first level and a second level.