# US 2019/0246398 A1 · Latency reduction techniques in wireless communications

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- Number: US 2019/0246398 A1
- Document ID: US20190246398A1
- Status: Published application
- Kind: A1
- Application number: 16/390,329
- Filed: 2019-04-22
- Published: 2019-08-08
- Earliest claimed: 2016-07-08
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Wanshi Chen; Seyedkianoush Hosseini; Peter Gaal; Srinivas Yerramalli; Hao Xu; Jing Sun; Shimman Arvind Patel; Aamod Kahandekar
- Web page: https://patentgrep.com/patent/US20190246398A1

## CPC

- H04L 1/1854: {Scheduling and prioritising arrangements}
- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 1/1812: Hybrid protocols; Hybrid automatic repeat request [HARQ]
- H04L 1/1861: {Physical mapping arrangements (for ACK signaling see also H04L5/0053)}
- H04L 1/1896: {ARQ related signaling}
- H04L 5/00: Arrangements affording multiple use of the transmission path
- H04L 5/001: {the frequencies being arranged in component carriers}
- 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 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)}
- H04L 5/0057: {Physical resource allocation for CQI}
- H04L 5/0094: {Indication of how sub-channels of the path are allocated}
- H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04L 5/0035: {Resource allocation in a cooperative multipoint environment}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04W 8/22: Processing or transfer of terminal data, e.g. status or physical capabilities
- H04W 88/02: Terminal devices
- 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

Methods, systems, and devices for wireless communication are described that provide for reduced timing between certain downlink communications and responsive uplink communications relative to certain legacy systems (e.g., legacy LTE systems). A user equipment (UE) or base station may be capable of operating using two or more timing configurations that each include an associated time period between receipt of a downlink communication (e.g., a grant of uplink resources or shared channel data) and a responsive uplink communication (e.g., an uplink transmission using the granted uplink resources or feedback of successful reception of the shared channel data). In cases where a UE or base station are capable of two or more timing configurations, a timing configuration for a transmission may be determined and the responsive uplink communication transmitted according to the determined timing configuration.

## Claims

### Claim 1

A method for wireless communication, comprising:
determining whether to use a first timing configuration, a second timing configuration, or a third timing configuration for transmissions, the first timing configuration including a first transmission time interval (TTI), the second timing configuration including a second TTI, the second TTI being less than the first TTI, and the third timing configuration including a third TTI, the third TTI being less than or equal to the second TTI, and wherein the determination is based at least in part on a capability of a user equipment (UE) to transmit a responsive uplink communication, responsive to a downlink communication, using the second timing configuration or the third timing configuration; and
transmitting according to the second timing configuration or the third timing configuration based on the determination.

### Claim 2 (depends on 1)

The method of claim 1, wherein the downlink communication contains an uplink grant and the responsive uplink communication uses resources identified in the uplink grant.

### Claim 3 (depends on 1)

The method of claim 1, wherein the downlink communication includes downlink data and the responsive uplink communication provides acknowledgment feedback of successful reception of the downlink data.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
receiving downlink control information (DCI) for the downlink communication; and
wherein transmitting according to the second timing configuration or the third timing configuration is further based at least in part on a format of the DCI.

### Claim 5 (depends on 4)

The method of claim 4, wherein the transmitting comprises:
transmitting according to the second timing configuration for a first subset of a set of available DCI formats; and
transmitting according to the third timing configuration for a second subset of the set of available DCI formats.

### Claim 6 (depends on 1)

The method of claim 1, wherein determining whether to use the first timing configuration, the second timing configuration, or the third timing configuration comprises:
identifying a maximum timing advance (TA) available for the responsive uplink communication; and
determining to use either the second timing configuration or the third timing configuration based at least in part on the maximum TA.

### Claim 7 (depends on 1)

The method of claim 1, wherein determining whether to use the first timing configuration, the second timing configuration, or the third timing configuration comprises:
identifying a maximum transport block size (TBS) available for the responsive uplink communication; and
determining to use either the second timing configuration or the third timing configuration based at least in part on the maximum TBS.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
receiving control information associated with the downlink communication in a control channel that spans an entire subframe; and
determining to use the second timing configuration for the responsive uplink communication based at least in part on the receiving.

### Claim 9 (depends on 1)

The method of claim 1, wherein downlink scheduling information for the third timing configuration is supported in a physical downlink control channel (PDCCH) transmission that spans only a subset of symbols of a subframe and is not supported in an enhanced physical downlink control channel (ePDCCH) transmission that spans an entire subframe.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
transmitting, by the UE, an indication of the capability of the UE to transmit the responsive uplink communication within the first TTI, the second TTI, or the third TTI.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
receiving, from the UE, an indication of the capability of the UE to transmit the responsive uplink communication within the first TTI, the second TTI, or the third TTI.

### Claim 12 (depends on 1)

The method of claim 1, wherein a maximum transport block size (TBS) available for either the second timing configuration or the third timing configuration is determined based at least in part on an indication of the capability of the UE to transmit the responsive uplink communication within the first TTI, the second TTI, or the third TTI.

### Claim 13 (depends on 1)

The method of claim 1, wherein a maximum transport block size (TBS) available for either the second timing configuration or the third timing configuration is determined based at least in part on a number of concurrent transmissions that may be received by the UE.

### Claim 14 (depends on 1)

The method of claim 1, wherein the downlink communication comprises an uplink grant that is provided no earlier than a latest subframe associated with acknowledgment receipt feedback to be transmitted using wireless resources identified in the uplink grant.

### Claim 15 (depends on 1)

The method of claim 1, further comprising:
receiving radio resource control (RRC) signaling that indicates the first timing configuration, the second timing configuration, or the third timing configuration.

### Claim 16 (depends on 1)

The method of claim 1, wherein the downlink communication is a physical downlink shared channel (PDSCH) transmission, and wherein the responsive uplink communication is a transmission of an asynchronous hybrid automatic repeat request (HARD) feedback associated with the PDSCH transmission.

### Claim 17 (depends on 16)

The method of claim 16, wherein a first number of HARQ processes associated with the first timing configuration is greater than a second number of HARQ processes associated with the second timing configuration, and wherein the second number of HARQ processes is greater than a third number of HARQ processes associated with the third timing configuration.

### Claim 18 (depends on 1)

The method of claim 1, further comprising:
identifying a periodicity for updating channel state information (CSI) based at least in part on the second timing configuration or the third timing configuration.

### Claim 19 (depends on 1)

The method of claim 1, further comprising:
determining an aperiodic channel state information (CSI) configuration based at least in part on a number of CSI processes supported for either the second timing configuration or the third timing configuration.

### Claim 20 (depends on 1)

The method of claim 1, further comprising:
identifying a sounding reference signal (SRS) parameter based at least in part on either the second timing configuration or the third timing configuration.

### Claim 21 (depends on 1)

The method of claim 1, wherein the downlink communication is transmitted using a set of component carriers, and wherein the second timing configuration is associated with a first subset of the set of component carriers and the third timing configuration is associated with a second subset of the set of component carriers.

### Claim 22 (depends on 21)

The method of claim 21, further comprising:
determining whether each of the first subset of component carriers and the second subset of component carriers support the third timing configuration;
transmitting using the third timing configuration for one or more of the first subset of component carriers or the second subset of component carriers when each of the first subset of component carriers and the second subset of component carriers support the third timing configuration; and
transmitting using the second timing configuration for each component carrier when one or more of the first subset of component carriers or the second subset of component carriers does not support the third timing configuration but does support the second timing configuration.

### Claim 23 (depends on 22)

The method of claim 22, wherein downlink scheduling information for the third timing configuration is supported in a physical downlink control channel (PDCCH) transmission and is not supported in an enhanced physical downlink control channel (ePDCCH) transmission.

### Claim 24 (depends on 22)

The method of claim 22, wherein downlink scheduling information for the second timing configuration is supported in both a physical downlink control channel (PDCCH) transmission and an enhanced physical downlink control channel (ePDCCH) transmission, and wherein available transport block sizes (TBSs) of the downlink scheduling information in the ePDCCH transmission is different than available TBSs in the PDCCH transmission.

### Claim 25 (depends on 21)

The method of claim 21, further comprising:
configuring one or more of channel state information (CSI) reporting or hybrid automatic repeat request (HARQ) feedback for the first subset of the set of component carriers based at least in part on the second timing configuration; and
configuring one or more of CSI reporting or HARQ feedback for the second subset of the set of component carriers based at least in part on the third timing configuration.

### Claim 26 (depends on 1)

The method of claim 1, further comprising:
configuring an uplink control channel resource indicator based on the second timing configuration for a first downlink communication using the second TTI;
determining that a second downlink communication is scheduled to use the third TTI based on the third timing configuration; and
updating the uplink control channel resource indicator based on the third timing configuration for the second downlink communication.

### Claim 27

An apparatus for wireless communication, comprising:
means for determining whether to use a first timing configuration, a second timing configuration, or a third timing configuration for transmissions, the first timing configuration including a first transmission time interval (TTI), the second timing configuration including a second TTI, the second TTI being less than the first TTI, and the third timing configuration including a third TTI, the third TTI being less than or equal to the second TTI, and wherein the determination is based at least in part on a capability of a user equipment (UE) to transmit a responsive uplink communication, responsive to a downlink communication, using the second timing configuration or the third timing configuration; and
means for transmitting according to the second timing configuration or the third timing configuration based on the determination.

### Claim 28

An apparatus for wireless communication, in a system comprising:
a processor;
memory coupled with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
determine whether to use a first timing configuration, a second timing configuration, or a third timing configuration for transmissions, the first timing configuration including a first transmission time interval (TTI), the second timing configuration including a second TTI, the second TTI being less than the first TTI, and the third timing configuration including a third TTI, the third TTI being less than or equal to the second TTI, and wherein the determination is based at least in part on a capability of a user equipment (UE) to transmit a responsive uplink communication, responsive to a downlink communication, using the second timing configuration or the third timing configuration; and
transmit according to the second timing configuration or the third timing configuration based on the determination.

### Claim 29 (depends on 28)

The apparatus of claim 28, wherein the instructions are further executable by the processor to cause the apparatus to:
receive downlink control information (DCI) for the downlink communication; and
wherein the instructions executable by the processor to cause the apparatus to transmit according to the second timing configuration or the third timing configuration are further executable by the processor to cause the apparatus to transmit according to the second timing configuration or the third timing configuration based at least in part on a format of the DCI.

### Claim 30 (depends on 29)

The apparatus of claim 29, wherein the instructions executable by the processor to cause the apparatus to transmit according to the second timing configuration or the third timing configuration are further executable by the processor to cause the apparatus to:
transmit according to the second timing configuration for a first subset of a set of available DCI formats; and
transmit according to the third timing configuration for a second subset of the set of available DCI formats.

### Claim 31 (depends on 28)

The apparatus of claim 28, wherein the instructions executable by the processor to cause the apparatus to determine whether to use the first timing configuration, the second timing configuration, or the third timing configuration are further executable by the processor to cause the apparatus to:
identify a maximum timing advance (TA) available for the responsive uplink communication; and
determine to use either the second timing configuration or the third timing configuration based at least in part on the maximum TA.

### Claim 32 (depends on 28)

The apparatus of claim 28, wherein the instructions executable by the processor to cause the apparatus to determine whether to use the first timing configuration, the second timing configuration, or the third timing configuration are further executable by the processor to cause the apparatus to:
identify a maximum transport block size (TBS) available for the responsive uplink communication; and
determine to use either the second timing configuration or the third timing configuration based at least in part on the maximum TBS.

### Claim 33 (depends on 28)

The apparatus of claim 28, wherein the instructions are further executable by the processor to cause the apparatus to:
receive control information associated with the downlink communication in a control channel that spans an entire subframe; and
determine to use the second timing configuration for the responsive uplink communication based at least in part on the receiving.

### Claim 34 (depends on 28)

The apparatus of claim 28, wherein the instructions are further executable by the processor to cause the apparatus to:
identify a periodicity for updating channel state information (CSI) based at least in part on the second timing configuration or the third timing configuration.

### Claim 35 (depends on 28)

The apparatus of claim 28, wherein the instructions are further executable by the processor to cause the apparatus to:
determine an aperiodic channel state information (CSI) configuration based at least in part on a number of CSI processes supported for either the second timing configuration or the third timing configuration.

### Claim 36 (depends on 28)

The apparatus of claim 28, wherein the instructions are further executable by the processor to cause the apparatus to:
identify a sounding reference signal (SRS) parameter based at least in part on either the second timing configuration or the third timing configuration.

### Claim 37

A non-transitory computer readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:
determine whether to use a first timing configuration, a second timing configuration, or a third timing configuration for transmissions, the first timing configuration including a first transmission time interval (TTI), the second timing configuration including a second TTI, the second TTI being less than the first TTI, and the third timing configuration including a third TTI, the third TTI being less than or equal to the second TTI, and wherein the determination is based at least in part on a capability of a user equipment (UE) to transmit a responsive uplink communication, responsive to a downlink communication, using the second timing configuration or the third timing configuration; and
transmit according to the second timing configuration or the third timing configuration based on the determination.