# US 10,313,160 B2 · Channel estimation enhancements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,313,160 B2 - Document ID: US10313160B2 - Status: Granted - Kind: B2 - Application number: 15/984,241 - Filed: 2018-05-18 - Published: 2018-09-20 - Granted: 2019-06-04 - Earliest claimed: 2014-10-31 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Jing Jiang; Krishna Kiran Mukkavilli; Naga Bhushan; Tingfang Ji; Joseph Binamira Soriaga; Peter Gaal; John Edward Smee; Alexei Yurievitch Gorokhov - Web page: https://patentgrep.com/patent/US10313160B2 ## CPC - H04L 25/0226: {sounding signals per se} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04L 5/0058: {Allocation criteria} - H04L 5/0082: {at predetermined intervals} - H04L 5/0096: {Indication of changes in allocation} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The disclosure relates in some aspects to techniques for improved channel estimation. For example, a device can specify a pilot structure where pilot density differs over time. As another example, a device can indicate that a pilot from a prior transmission time interval (TTI) can be used for channel estimation. As another example, a device can employ frequency domain physical resource block (PRB) bundling with the bundling information signaling. As yet another example, a device can use an adjustable traffic-to-pilot ratio (TPR) for throughput optimization. Other aspects, embodiments, and features are also discussed and claimed. ## Claims ### Claim 1 An apparatus for wireless communication, comprising: a processing circuit configured to determine a traffic-to-pilot ratio (TPR) for a user equipment (UE) for demodulation reference signals (DMRSs) based on at least a rate associated with the UE; and a communication interface coupled to the processing circuit and configured to transmit an indication of the TPR to the UE. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processing circuit is further configured to obtain channel condition information for the UE and select the TPR for the UE further based on the channel condition. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the processing circuit is further configured to select a DMRS power based on at least the rate, and to determine the TPR based on the DMRS power. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein: the processing circuit is further configured to determine a pilot structure where pilot density differs over time within a transmission period; and the communication interface is further configured to transmit an indication of the pilot structure. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the pilot density at a beginning portion of the transmission period is higher than the pilot density at a later portion of the transmission period. ### Claim 6 (depends on 4) The apparatus of claim 4, wherein the pilot density is different for different transmission time intervals (TTIs) within the transmission period. ### Claim 7 (depends on 4) The apparatus of claim 4, wherein the pilot density further differs with respect to frequency during the transmission period. ### Claim 8 (depends on 4) The apparatus of claim 4, wherein the processing circuit is further configured to: change a beamforming configuration; and determine the pilot structure as a result of the changed beamforming configuration. ### Claim 9 (depends on 4) The apparatus of claim 4, wherein: the processing circuit is further configured to determine that a particular pilot structure is specified for successive transmission time intervals (TTIs); and the communication interface is further configured to transmit an indication that a pilot from a prior TTI can be used for channel estimation as a result of the determination that a particular pilot structure is specified for successive TTIs. ### Claim 10 (depends on 4) The apparatus of claim 4, wherein: the processing circuit is further configured to identify a physical resource block (PRB) bundle that comprises at least one PRB; the processing circuit is further configured to select another pilot structure based on the identified PRB bundle; and the communication interface is further configured to transmit an indication of the selected other pilot structure. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein, to select the other pilot structure, the processing circuit is further configured to select spacing for pilots based on a bandwidth of the PRB bundle. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein the indication of the selected other pilot structure comprises a precoding matrix indicator (PMI). ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the indication of the selected other pilot structure indicates a difference between neighbor resource block (RB) PMIs. ### Claim 14 A method of wireless communication, comprising: determining a traffic-to-pilot ratio (TPR) for a user equipment (UE) for demodulation reference signals (DMRSs) based on at least a rate associated with the UE; and transmitting an indication of the TPR to the UE. ### Claim 15 (depends on 14) The method of claim 14, wherein determining the TPR further comprises: obtaining channel condition information for the UE; and selecting the TPR for the UE further based on the channel condition. ### Claim 16 (depends on 14) The method of claim 14, wherein determining the TPR further comprises: selecting a DMRS power based on at least the rate; and determining the TPR based on the DMRS power. ### Claim 17 (depends on 14) The method of claim 14, further comprising: determining a pilot structure where pilot density differs over time within a transmission period; and transmitting an indication of the pilot structure. ### Claim 18 (depends on 17) The method of claim 17, wherein the pilot density at a beginning portion of the transmission period is higher than the pilot density at a later portion of the transmission period. ### Claim 19 (depends on 17) The method of claim 17, wherein the pilot density is different for different transmission time intervals (TTIs) within the transmission period. ### Claim 20 (depends on 17) The method of claim 17, wherein the pilot density further differs with respect to frequency during the transmission period. ### Claim 21 (depends on 17) The method of claim 17, further comprising: changing a beamforming configuration; and determining the pilot structure as a result of the changed beamforming configuration. ### Claim 22 (depends on 17) The method of claim 17, further comprising: determining that a particular pilot structure is specified for successive transmission time intervals (TTIs); and transmitting an indication that a pilot from a prior TTI can be used for channel estimation as a result of the determination that a particular pilot structure is specified for successive TTIs. ### Claim 23 (depends on 17) The method of claim 17, further comprising: identifying a physical resource block (PRB) bundle that comprises at least one PRB; selecting another pilot structure based on the identified PRB bundle; and transmitting an indication of the selected other pilot structure. ### Claim 24 An apparatus for wireless communication, comprising: means for determining a traffic-to-pilot ratio (TPR) for a user equipment (UE) for demodulation reference signals (DMRSs) based on at least a rate associated with the UE; and means for transmitting an indication of the TPR to the UE. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the means for determining the TPR further comprises: means for obtaining channel condition information for the UE; and means for selecting the TPR for the UE further based on the channel condition. ### Claim 26 (depends on 24) The apparatus of claim 24, wherein the means for determining the TPR further comprises: means for selecting a DMRS power based on at least the rate; and means for determining the TPR based on the DMRS power. ### Claim 27 (depends on 24) The apparatus of claim 24, further comprising: means for determining a pilot structure where pilot density differs over time within a transmission period; and means for transmitting an indication of the pilot structure. ### Claim 28 (depends on 27) The apparatus of claim 27, further comprising: means for changing a beamforming configuration; and means for determining the pilot structure as a result of the changed beamforming configuration. ### Claim 29 (depends on 27) The apparatus of claim 27, further comprising: means for determining that a particular pilot structure is specified for successive transmission time intervals (TTIs); and means for transmitting an indication that a pilot from a prior TTI can be used for channel estimation as a result of the determination that a particular pilot structure is specified for successive TTIs. ### Claim 30 (depends on 27) The apparatus of claim 27, further comprising: means for identifying a physical resource block (PRB) bundle that comprises at least one PRB; means for selecting another pilot structure based on the identified PRB bundle; and means for transmitting an indication of the selected other pilot structure.