# US 2020/0403656 A1 · User equipment initiated channel state feedback codebook selection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403656 A1 - Document ID: US20200403656A1 - Status: Published application - Kind: A1 - Application number: 16/449,293 - Filed: 2019-06-21 - Published: 2020-12-24 - Earliest claimed: 2019-06-21 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Parisa CHERAGHI; Alexei Yurievitch GOROKHOV - Web page: https://patentgrep.com/patent/US20200403656A1 ## CPC - H04B 7/0417: Feedback systems - H04B 7/0452: Multi-user MIMO systems - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04B 17/336: Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] - H04B 7/0482: {Adaptive codebooks} - Y02D 30/70: in wireless communication networks - H04B: TRANSMISSION - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract Aspects are provided allowing a UE configured for Type II channel state feedback (CSF) to determine based on one or more antenna configurations or channel conditions whether to use the Type II codebook or to revert to a Type I codebook when computing CSF. Based on this determination, the UE may compute CSF based on the Type I codebook in situations where the performance gain of Type II codebooks may be reduced, thereby saving computational power, transmission power, and/or overhead when computing and reporting CSI feedback. The UE may subsequently transmit the CSF computed based on the Type I codebook in the allocated resources for Type II CSI feedback without the need for a separate signaling format, thereby simplifying and enabling reuse of the CSI feedback procedure. ## Claims ### Claim 1 A method of wireless communication at a user equipment (UE), comprising: receiving a configuration from a base station to transmit channel state feedback (CSF) using a first codebook type; determining whether to transmit the CSF using the first codebook type or a second codebook type; and transmitting the CSF using a selected codebook type based on a determination of whether to transmit the CSF using the first codebook type or the second codebook type. ### Claim 2 (depends on 1) The method of claim 1, wherein the first codebook type comprises a Type II codebook and the second codebook type comprises a Type I codebook. ### Claim 3 (depends on 1) The method of claim 1, wherein the UE determines to transmit the CSF using the second codebook type based on one or more of an antenna configuration or a channel condition. ### Claim 4 (depends on 3) The method of claim 3, wherein the antenna configuration comprises a number of antenna ports, and wherein the UE determines to transmit the CSF using the second codebook type when the number of antenna ports is lower than an antenna port threshold and determines to transmit the CSF using the first codebook type when the number of antenna ports meets the antenna port threshold. ### Claim 5 (depends on 3) The method of claim 3, wherein the antenna configuration comprises an antenna correlation, and wherein the UE determines to transmit the CSF using the first codebook type when the antenna correlation is below a correlation threshold and determines to transmit the CSF using the second codebook type when the antenna correlation exceeds the correlation threshold. ### Claim 6 (depends on 3) The method of claim 3, wherein the antenna configuration comprises a number of beams configured for the second codebook type, and wherein the UE determines to transmit the CSF using the first codebook type when the number of beams meets a beam threshold and determines to transmit the CSF using the second codebook type when the number of beams is lower than the beam threshold. ### Claim 7 (depends on 3) The method of claim 3, wherein the channel condition comprises a signal-to-noise ratio (SNR), and wherein the UE determines to transmit the CSF using the first codebook type when the SNR is below an SNR threshold and determines to transmit the CSF using the second codebook type when the SNR meets the SNR threshold. ### Claim 8 (depends on 3) The method of claim 3, wherein the channel condition comprises a number of users communicating based on multi-user multiple-input-multiple-output (MU-MIMO), and wherein the UE determines to transmit the CSF using the first codebook type when the number of users is below a user threshold and determines to transmit the CSF using the second codebook type when the number of users meets the user threshold. ### Claim 9 (depends on 3) The method of claim 3, wherein the channel condition comprises at least one of a statistical channel property or interference from other users, and wherein the UE determines to transmit the CSF using the second codebook type based on the statistical channel property or interference. ### Claim 10 (depends on 3) The method of claim 3, further comprising: computing the CSF using the second codebook type based on the determination. ### Claim 11 (depends on 1) The method of claim 1, further comprising: transmitting the CSF using the second codebook type within a container in uplink control information (UCI) for the first codebook type. ### Claim 12 An apparatus for wireless communication, comprising: means for receiving a configuration from a base station to transmit channel state feedback (CSF) using a first codebook type; means for determining whether to transmit the CSF using the first codebook type or a second codebook type; and means for transmitting the CSF using a selected codebook type based on a determination of whether to transmit the CSF using the first codebook type or the second codebook type. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the means for determining is configured to determine to transmit the CSF using the second codebook type based on one or more of an antenna configuration or a channel condition. ### Claim 14 (depends on 13) The apparatus of claim 13, further comprising: means for computing the CSF using the second codebook type based on the determination. ### Claim 15 (depends on 12) The apparatus of claim 12, further comprising: means for transmitting the CSF using the second codebook type within a container in uplink control information (UCI) for the first codebook type. ### Claim 16 An apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to: receive a configuration from a base station to transmit channel state feedback (CSF) using a first codebook type; determine whether to transmit the CSF using the first codebook type or a second codebook type; and transmit the CSF using a selected codebook type based on a determination of whether to transmit the CSF using the first codebook type or the second codebook type. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the first codebook type comprises a Type II codebook and the second codebook type comprises a Type I codebook. ### Claim 18 (depends on 16) The apparatus of claim 16, wherein the at least one processor is configured to determine to transmit the CSF using the second codebook type based on one or more of an antenna configuration or a channel condition. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the antenna configuration comprises a number of antenna ports, and wherein the at least one processor is configured to determine to transmit the CSF using the second codebook type when the number of antenna ports is lower than an antenna port threshold and to determine to transmit the CSF using the first codebook type when the number of antenna ports meets the antenna port threshold. ### Claim 20 (depends on 18) The apparatus of claim 18, wherein the antenna configuration comprises an antenna correlation, and wherein the at least one processor is configured to determine to transmit the CSF using the first codebook type when the antenna correlation is below a correlation threshold and to determine to transmit the CSF using the second codebook type when the antenna correlation exceeds the correlation threshold. ### Claim 21 (depends on 18) The apparatus of claim 18, wherein the antenna configuration comprises a number of beams configured for the second codebook type, and wherein the at least one processor is configured to determine to transmit the CSF using the first codebook type when the number of beams meets a beam threshold and to determine to transmit the CSF using the second codebook type when the number of beams is lower than the beam threshold. ### Claim 22 (depends on 18) The apparatus of claim 18, wherein the channel condition comprises a signal-to-noise ratio (SNR), and wherein the at least one processor is configured to determine to transmit the CSF using the first codebook type when the SNR is below an SNR threshold and to determine to transmit the CSF using the second codebook type when the SNR meets the SNR threshold. ### Claim 23 (depends on 18) The apparatus of claim 18, wherein the channel condition comprises a number of users communicating based on multi-user multiple-input-multiple-output (MU-MIMO), and wherein the at least one processor is configured to determine to transmit the CSF using the first codebook type when the number of users is below a user threshold and to determine to transmit the CSF using the second codebook type when the number of users meets the user threshold. ### Claim 24 (depends on 18) The apparatus of claim 18, wherein the channel condition comprises at least one of a statistical channel property or interference from other users, and wherein the at least one processor is configured to determine to transmit the CSF using the second codebook type based on the statistical channel property or interference. ### Claim 25 (depends on 18) The apparatus of claim 18, wherein the at least one processor is further configured to: compute the CSF using the second codebook type based on the determination. ### Claim 26 (depends on 16) The apparatus of claim 16, wherein the at least one processor is further configured to: transmit the CSF using the second codebook type within a container in uplink control information (UCI) for the first codebook type. ### Claim 27 A computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to: receive a configuration from a base station to transmit channel state feedback (CSF) using a first codebook type; determine whether to transmit the CSF using the first codebook type or a second codebook type; and transmit the CSF using a selected codebook type based on a determination of whether to transmit the CSF using the first codebook type or the second codebook type. ### Claim 28 (depends on 27) The computer-readable medium of claim 27, wherein the code when executed by the processor cause the processor to determine to transmit the CSF using the second codebook type based on one or more of an antenna configuration or a channel condition. ### Claim 29 (depends on 28) The computer-readable medium of claim 28, wherein the code when executed by the processor further cause the processor to: compute the CSF using the second codebook type based on the determination. ### Claim 30 (depends on 27) The computer-readable medium of claim 27, wherein the code when executed by the processor further cause the processor to: transmit the CSF using the second codebook type within a container in uplink control information (UCI) for the first codebook type.