# US 2019/0245608 A1 · Method of constructing codebook with multiple resolution and user equipment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0245608 A1 - Document ID: US20190245608A1 - Status: Published application - Kind: A1 - Application number: 16/345,181 - Filed: 2017-10-25 - Published: 2019-08-08 - Earliest claimed: 2016-10-25 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Yuichi Kakishima; Chongning Na; Huiling Li; Huiling Jiang; Satoshi Nagata - Web page: https://patentgrep.com/patent/US20190245608A1 ## CPC - H04B 7/0478: {Special codebook structures directed to feedback optimisation} - H04B 7/0417: Feedback systems - H04B 7/0617: {for beam forming} - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04W 88/02: Terminal devices - H04B 7/0619: {using feedback from receiving side (feedback signaling for adaptive modulation/coding H04L1/0001)} - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method of constructing a codebook with multiple resolution in a wireless communication system includes constructing, with a user equipment (UE), a high resolution codebook using a low resolution codebook; and transmitting, from the UE to a base station (BS), Channel State Information (CSI) feedback in accordance with a feedback scheme corresponding to the high resolution codebook or the low resolution codebook. The high resolution codebook defines the feedback scheme corresponding to the high resolution codebook. The method further comprises selecting, with the UE, multiple first beams from multiple second beams used for downlink transmission from the BS. The constructing constructs the high resolution codebook based on the multiple first beams, and the low resolution codebook is constructed based on a single beam selection scheme that selects a single beam. ## Claims ### Claim 1 A method of constructing a codebook with multiple resolution in a wireless communication system comprising: constructing, with a user equipment (UE), a high resolution codebook using a low resolution codebook; and transmitting, from the UE to a base station (BS), Channel State Information (CSI) feedback in accordance with a feedback scheme corresponding to the high resolution codebook or the low resolution codebook. ### Claim 2 (depends on 2) The method according to claim 2, wherein the high resolution codebook defines the feedback scheme corresponding to the high resolution codebook. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: selecting, with the UE, multiple first beams from multiple second beams used for downlink transmission from the BS, wherein the constructing constructs the high resolution codebook based on the multiple first beams, and wherein the low resolution codebook is constructed based on a single beam selection scheme that selects a single beam. ### Claim 4 (depends on 3) The method according to claim 3, wherein the selecting selects the multiple first beams based on the low resolution codebook. ### Claim 5 (depends on 3) The method according to claim 3, wherein the selecting selects the multiple first beams based on a rank 1 beam selection scheme of a Long Term Evolution (LTE) standard. ### Claim 6 (depends on 3) The method according to claim 3, wherein the selecting selects the multiple first beams based on a rank 3 beam selection scheme of a LTE standard. ### Claim 7 (depends on 3) The method according to claim 3, wherein the multiple first beams include a leading beam, and wherein when a rank 1 codebook is used for a normal CSI feedback scheme, the leading beam is the same as a rank 1 beam used to construct the rank 1 codebook. ### Claim 8 (depends on 7) The method according to claim 7, wherein beams other than the leading beam in the multiple first beams are orthogonal to the leading beam. ### Claim 9 (depends on 3) The method according to claim 3, wherein the multiple first beams include a leading beam, and wherein when a rank 3 codebook is used for a normal CSI feedback scheme, the leading beam is the same as one of beams of a rank 3 codebook beam group to construct the rank 3 codebook. ### Claim 10 (depends on 9) The method according to claim 9, wherein beams other than the leading beam in the multiple first beams are beams other than the one of beams of the rank 3 codebook beam group. ### Claim 11 (depends on 1) The method according to claim 1, wherein the low resolution codebook reuses a legacy beam and a same beam selection scheme under a LTE standard. ### Claim 12 (depends on 1) The method according to claim 1, wherein the high resolution codebook reuses a rank 1 beam selection scheme or a rank 3 beam selection scheme of a LTE standard. ### Claim 13 (depends on 12) The method according to claim 12, wherein the high resolution codebook reuses the rank 1 beam selection scheme when beam selection has no group constrain. ### Claim 14 (depends on 12) The method according to claim 12, wherein the low resolution codebook reuses the rank 3 beam selection scheme when beam selection has group constrain. ### Claim 15 (depends on 12) The method according to claim 12, wherein the low resolution codebook reuses the rank 3 beam selection scheme when beam selection has no group constrain ### Claim 16 (depends on 1) The method according to claim 1, wherein the feedback scheme comprises a hierarchical feedback framework to support normal CSI feedback and advanced CSI feedback. ### Claim 17 (depends on 1) The method according to claim 1, further comprising: notifying, with the BS, the UE of a CSI feedback type, wherein the CSI feedback type indicates normal CSI feedback or advanced CSI feedback, and wherein the transmitting transmits the CSI feedback in accordance with the CSI feedback type. ### Claim 18 (depends on 17) The method according to claim 17, wherein the normal CSI feedback and the advanced CSI feedback different feedback delays. ### Claim 19 A user equipment (UE) comprising: a processor that constructs a high resolution codebook using a low resolution codebook; and a transmitter that transmits, to a base station (BS), Channel State Information (CSI) feedback in accordance with a feedback scheme corresponding to the high resolution codebook or the low resolution codebook. ### Claim 20 (depends on 19) The UE according to claim 19, wherein the processor selects multiple first beams from multiple second beams used for downlink transmission from the BS, wherein the processor constructs the high resolution codebook based on the multiple first beams, and wherein the low resolution codebook is constructed based on a single beam selection scheme that selects a single beam.