# US 11,452,075 B2 · Regional and narrow band common reference signal (CRS) for user equipment (UE) relays > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,452,075 B2 - Document ID: US11452075B2 - Status: Granted - Kind: B2 - Application number: 17/007,226 - Filed: 2020-08-31 - Published: 2020-12-24 - Granted: 2022-09-20 - Earliest claimed: 2012-01-27 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Wanshi Chen; Aleksandar Damnjanovic; Juan Montojo - Web page: https://patentgrep.com/patent/US11452075B2 ## CPC - H04W 72/04: Wireless resource allocation - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 5/0023: {Time-frequency-space} - H04L 5/003: {Arrangements for allocating sub-channels of the transmission path} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 88/04: adapted for relaying to or from another terminal or user - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Certain aspects of the present disclosure relate to techniques for assigning resources for common reference signal (CRS) transmissions from user equipment (UE) relays. Aspects of the present disclosure provide techniques to use minimum possible resources for transmission of CRS in an attempt to reduce interference, reduce power consumption while providing appropriate reference for channel measurement and demodulation. In an aspect, a wireless node (e.g., a UE relay station) may determine resources for transmission of CRS in a subframe based, at least in part, on a type of one or more channels to be transmitted in the subframe, and may transmit the CRS using the determined resources. ## Claims ### Claim 1 A method of wireless communications by a wireless node, the method comprising: determining a minimum amount of narrowband resources for transmission of a common reference signal (CRS) in a subframe to at least one User Equipment (UE) configured for wideband operation based, at least in part, on a type of one or more channels to be transmitted in the subframe, wherein the minimum amount of narrowband resources for transmission of the CRS is required by the at least one UE to perform one or more functions relating to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and transmitting the CRS using the determined resources. ### Claim 2 (depends on 1) The method of claim 1, wherein the determined narrowband resources comprise a narrowband portion of overall bandwidth allocated to the subframe. ### Claim 3 (depends on 1) The method of claim 1, wherein: the determined narrowband resources span a length of the subframe if at least one of a physical broadcast channel (PBCH), primary synchronization signal (PSS), or secondary synchronization signal (SSS) is to be transmitted in the subframe, wherein the length spans both a control region and a data region. ### Claim 4 (depends on 1) The method of claim 1, wherein: the determined narrowband resources span only a portion of a control region of the subframe if none of a physical broadcast channel (PBCH), primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical downlink control channel (PDCCH) is to be transmitted in the subframe. ### Claim 5 An apparatus for wireless communications, comprising: means for determining a minimum amount of narrowband resources for transmission of a common reference signal (CRS) in a subframe to at least one User Equipment (UE) configured for wideband operation, based, at least in part, on one or more channels to be transmitted in the subframe, wherein the minimum amount of narrowband resources for transmission of the CRS is required by the at least one UE to perform one or more functions relating to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and means for transmitting the CRS using the determined narrowband resources. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the determined narrowband resources comprise a narrowband portion of overall bandwidth allocated to the subframe. ### Claim 7 (depends on 5) The apparatus of claim 5, wherein: the determined narrowband resources span a length of the subframe if at least one of a physical broadcast channel (PBCH), primary synchronization signal (PSS), or secondary synchronization signal (SSS) is to be transmitted in the subframe, wherein the length spans both a control region and a data region. ### Claim 8 (depends on 5) The apparatus of claim 5, wherein: the determined narrowband resources span only a portion of a control region of the subframe if none of a physical broadcast channel (PBCH), primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical downlink control channel (PDCCH) is to be transmitted in the subframe. ### Claim 9 An apparatus for wireless communications, comprising: at least one processor, and memory coupled to the at least one processor, the memory comprising instructions executable by the at least one processor to cause the apparatus to: determine a minimum amount of narrowband resources for transmission of a common reference signal (CRS) in a subframe to at least one User Equipment (UE) configured for wideband operation, based, at least in part, on one or more channels to be transmitted in the subframe, wherein the minimum amount of narrowband resources for transmission of the CRS is required by the at least one UE to perform one or more functions relating to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and transmit the CRS using the determined narrowband resources. ### Claim 10 A non-transitory computer-readable medium having instructions stored thereon which, when executed by one or more processors, performs an operation for wireless communications, the operation comprising: determining an amount of narrowband resources for transmission of a common reference signal (CRS) in a subframe to at least one User Equipment (UE) configured for wideband operation, based, at least in part, on one or more channels to be transmitted in the subframe, wherein the minimum amount of narrowband resources for transmission of the CRS is required by the at least one UE to perform one or more functions relating to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and transmitting the CRS using the determined narrowband resources. ### Claim 11 A method of wireless communications by a User Equipment (UE) configured for wideband operation, the method comprising: receiving a common reference signal (CRS) in a subframe; determining a minimum amount of narrowband resources used for transmission of the CRS in the subframe based, at least in part, on one or more functions the UE is to perform with reference to one or more channels received in the subframe, wherein the minimum amount of the narrowband resources for transmission of the CRS is required for performing the one or more functions with reference to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and processing the subframe based on the determination. ### Claim 12 (depends on 11) The method of claim 11, wherein the determined narrowband resources comprise a narrowband portion of overall bandwidth allocated to the subframe. ### Claim 13 (depends on 11) The method of claim 11, wherein: the determined narrowband resources span a length of the subframe if the one or more functions comprise decoding at least one of a physical broadcast channel (PBCH), primary synchronization signal (PSS), or secondary synchronization signal (SSS) transmitted in the subframe, wherein the length spans both a control region and a data region. ### Claim 14 (depends on 11) The method of claim 11, wherein: the determined narrowband resources span only a portion of a control region of the subframe if the one or more functions comprise decoding none of a physical broadcast channel (PBCH), primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical downlink control channel (PDCCH). ### Claim 15 An apparatus for wireless communications configured for wideband operation, comprising: means for receiving a common reference signal (CRS) in a subframe; means for determining an amount of narrowband resources used for transmission of the received CRS in the subframe based, at least in part, on one or more functions a UE is to perform with reference to one or more channels received in the subframe, wherein the minimum amount of the narrowband resources for transmission of the CRS is required for performing the one or more functions with reference to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and means for processing the subframe based on the determination. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the determined narrowband resources comprise a narrowband portion of overall bandwidth allocated to the subframe. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein: the determined narrowband resources span a length of the subframe if the one or more functions comprise decoding at least one of a physical broadcast channel (PBCH), primary synchronization signal (PSS), or secondary synchronization signal (SSS) transmitted in the subframe, wherein the length spans both a control region and a data region. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein: the determined narrowband resources span only a portion of a control region of the subframe if the one or more functions comprise decoding none of a physical broadcast channel (PBCH), primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical downlink control channel (PDCCH). ### Claim 19 An apparatus for wireless communications configured for wideband operation, comprising: at least one processor, and memory coupled to the at least one processor, the memory comprising instructions executable by the at least one processor to cause the apparatus to: receive a common reference signal (CRS) in a subframe; determine a minimum amount of narrowband resources used for transmission of the received CRS in the subframe based, at least in part, on one or more functions a UE is to perform with reference to one or more channels received in the subframe, wherein the minimum amount of the narrowband resources for transmission of the CRS is required for performing the one or more functions with reference to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and process the subframe based on the determination. ### Claim 20 A non-transitory computer-readable medium having instructions thereon which, when executed by one or more processors, performs an operation for wireless communications by a User Equipment (UE) configured for wideband operation, the operation comprising: receiving a common reference signal (CRS) in a subframe; determining a minimum amount of narrowband resources used for transmission of the received CRS in the subframe based, at least in part, on one or more functions a UE is to perform with reference to one or more channels received in the subframe, wherein the minimum amount of the narrowband resources for transmission of the CRS is required for performing the one or more functions with reference to the one or more channels and the one or more functions comprise measuring channel quality based on the narrowband resources; and processing the subframe based on the determination.