Patent Description:
Some relevant prior art:.

<NPL>, relates to short HARQ timing for NR frame structures. <NPL> relates to a discussion on processing time reduction and related procedures for short TTI.

In some cases, a wireless system may increase the reliability of its communications by employing an error correction mechanism, such as hybrid automatic repeat request (HARQ). In HARQ, a UE that receives data from a base station may send an acknowledgement (ACK) or negative acknowledgment (NACK) to the base station indicating whether the data was successfully received and decoded (e.g., whether the received data passes an error detection check). If the data is successfully decoded, the UE may enter into a low power mode to save energy after responding with an ACK.

A user equipment (UE) may send an acknowledgment (ACK) or negative acknowledgement (NACK) to a base station after the UE receives a downlink data transmission sent in a physical downlink shared channel (PDSCH). In some cases, the UE may enter into a low power mode (e.g., sleep mode) after sending the ACK/NACK. In some cases, the UE may be operating according to a hybrid automatic repeat request (HARQ) protocol that operates according to a fixed duration of time (e.g., <NUM>) between received PDSCH transmissions and sending ACK/NACK. Because the transmission parameters associated with the downlink data transmission may vary (e.g., the transport block size, number of layers, repetition level coding type, etc.), the fixed duration of time may be designed to handle the worst case processing time for the data (e.g., the worst case processing time to decode the PDSCH and prepare for an uplink ACK/NACK transmission). The UE may be prevented from entering into the low power mode until it sends an ACK/NACK, which may increase the power expenditure of the UE. Additionally or alternatively, using a fixed delay to send ACKs/NACKs, regardless of a UE's capabilities, may prevent more powerful UEs from taking advantage of their faster processing capabilities. For instance, a UE supporting enhanced Machine Type Communications (eMTC) may be able to process an entire Narrow-Band Internet of Things (NB-IoT) PDSCH in a subframe (e.g., in <NUM>), but a low cost UE specifically designed for NB-IoT may require more subframes. Using the same delay for both UEs may prevent the more powerful UE from entering into low power mode earlier or more efficiently communicating data.

According to the techniques described herein, a UE may select a delay that corresponds to its ability to process downlink data. For example, a UE may select a delay that allows the UE to enter into a low power mode shortly after it finishes processing a downlink transmission. The UE may select the delay based on the processing capabilities of the UE (which may be a function of the UE's design) and/or based on the transmission parameters of the downlink data transmission (e.g., the UE may select a delay based on the transport block size of the downlink transmission). By tailoring the delay to the UE's ability to process the downlink data, the UE may spend more time in low power mode and increase its power savings. Additionally or alternatively, the UE may spend more time sending or receiving other signals, which may increase throughput.

<FIG> illustrates an example of a wireless communications system <NUM> in accordance with various aspects of the present disclosure. The wireless communications system <NUM> includes base stations <NUM>, UEs <NUM>, and a core network <NUM>. In some examples, the wireless communications system <NUM> may be a Long Term Evolution (LTE), LTE-Advanced (LTE-A) network, or a New Radio (NR) network. In some cases, wireless communications system <NUM> may support enhanced broadband communications, ultra-reliable (i.e., mission critical) communications, low latency communications, and communications with low-cost and low-complexity devices. According to the techniques described herein, a UE <NUM> may recognize when there is an opportunity for the UE <NUM> to reduce delays in an error correction scheme and may adjust its communications to effectuate that reduction.

In one example, a UE <NUM> and a base station <NUM> may participate in hybrid automatic repeat request (HARQ) processes that increase the reliability of communications between the UE <NUM> and the base station <NUM>. In HARQ, control messages are transmitted by a UE <NUM> to indicate the receipt status of data sent by a base station <NUM>. If the UE <NUM> cannot successfully process the data, the UE <NUM> may send a negative acknowledgement (NACK) to the base station <NUM>. The NACK may prompt the base station <NUM> to resend the data so that the UE <NUM> successfully process it. If the UE <NUM> successfully receives the data, the UE <NUM> may send an acknowledgement (ACK) to the base station <NUM>. The ACK may inform the base station <NUM> that the data was successfully processed and does not need to be resent. In some cases, HARQ processes may be supplemented by increasing the repetition level of the data. For example, multiple (e.g., redundant) versions of the data may be sent (e.g., in back-to-back subframe) so that the UE <NUM> has a greater likelihood of successfully processing the data (e.g., by combining the different versions of the data).

In some cases, there may be a fixed delay in between receiving data and sending an ACK or NACK (e.g., a PDSCH-to-ACK/NACK delay). For example, a HARQ process may operate according to a fixed delay between PDSCH and ACK/NACK. The amount of time may be designed to cover the worst-case processing time for the data across varying transmissions and UE capabilities. A UE <NUM> with higher processing capabilities may, after finishing processing of data transmissions, have to wait for the fixed delay to elapse. Waiting for the fixed delay to expire may prevent the UE <NUM> from entering into a low power mode, which may increase the power expenditure of the UE <NUM>. Additionally or alternatively, waiting for the fixed delay to expire may prevent the UE <NUM> from engaging in other communications, which may reduce the throughput of the UE <NUM>.

According to the techniques described herein, a UE <NUM> may operate according to a HARQ process with an adjustable PDSCH-to-ACK/NACK delay. The delay selected by the UE <NUM> may take into account the UE-specific processing time for a downlink transmission. For example, the UE <NUM> may select a delay that corresponds to how fast the UE <NUM> can process the data and prepare the ACK or NACK for transmission. The downlink processing abilities of the UE <NUM> may be factored into the delay (e.g., the UE <NUM> may select a capability-dependent delay), and/or the transmission parameters associated with the data may be factored into the delay (e.g., the UE <NUM> may select a transmission-dependent delay). However, the delay may be independent of the type of UE <NUM>, and/or type of communications in which the UE <NUM> is engaging. Thus, the delays used by two UEs <NUM> may differ, even if the UEs <NUM> are of the same type (e.g., both NB-IoT UEs) and are participating in the same type of communications.

Each base station <NUM> may provide communication coverage for a respective geographic coverage area <NUM>. Control information and data may be multiplexed on an uplink channel or downlink according to various techniques. Control information and data may be multiplexed on a downlink channel, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, the control information transmitted during a transmission time interval (TTI) of a downlink channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region and one or more UE-specific control regions).

In some examples, the base stations <NUM> and UEs <NUM> may communicate using narrowband internet of things (NB-IoT) technology. NB-IoT technology may operate over a frequency band having a defined bandwidth, and the frequency band may correspond to one resource block in LTE transmission (e.g., <NUM> bandwidth). NB-IoT technology supports three modes of operation: stand-alone operation, guard band operation, and in-band operation. In stand-alone operation, frequencies are defined in which the base station <NUM>-a and UE <NUM>-a may communicate. In guard band operation, the base station <NUM>-a and UE <NUM>-a may communicate using unused resource blocks within a guard-band of a cellular carrier (e.g., LTE carrier). In in-band operation, the base station <NUM>-a and UE <NUM>-a may communicate using resource blocks within a cellular carrier (e.g., an LTE carrier). The examples provided herein may be used in any of these modes.

A UE <NUM> may also be referred to as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may also be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a personal electronic device, a handheld device, a personal computer, a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, a machine type communication (MTC) device, an appliance, an automobile, or the like. In some instances, a UE <NUM> may be a NB-IoT device with limited processing capabilities and/or battery life.

Wireless communications system <NUM> may operate in an ultra-high frequency (UHF) frequency region using frequency bands from <NUM> to <NUM> (<NUM>), although some networks (e.g., a wireless local area network (WLAN)) may use frequencies as high as <NUM>. This region may also be known as the decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may propagate mainly by line of sight, and may be blocked by buildings and environmental features. However, the waves may penetrate walls sufficiently to provide service to UEs <NUM> located indoors. Transmission of UHF waves is characterized by smaller antennas and shorter range (e.g., less than <NUM>) compared to transmission using the smaller frequencies (and longer waves) of the high frequency (HF) or very high frequency (VHF) portion of the spectrum. In some cases, wireless communications system <NUM> may also utilize extremely high frequency (EHF) portions of the spectrum (e.g., from <NUM> to <NUM>). This region may also be known as the millimeter band, since the wavelengths range from approximately one millimeter to one centimeter in length. Thus, EHF antennas may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE <NUM> (e.g., for directional beamforming). However, EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than UHF transmissions.

Thus, wireless communications system <NUM> may support millimeter wave (mmW) communications between UEs <NUM> and base stations <NUM>. Devices operating in mmW or EHF bands may have multiple antennas to allow beamforming. That is, a base station <NUM> may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE <NUM>. Beamforming (which may also be referred to as spatial filtering or directional transmission) is a signal processing technique that may be used at a transmitter (e.g., a base station <NUM>) to shape and/or steer an overall antenna beam in the direction of a target receiver (e.g., a UE <NUM>). This may be achieved by combining elements in an antenna array in such a way that transmitted signals at particular angles experience constructive interference while others experience destructive interference.

Multiple-input multiple-output (MIMO) wireless systems use a transmission scheme between a transmitter (e.g., a base station <NUM>) and a receiver (e.g., a UE <NUM>), where both transmitter and receiver are equipped with multiple antennas. Some portions of wireless communications system <NUM> may use beamforming. For example, base station <NUM> may have an antenna array with a number of rows and columns of antenna ports that the base station <NUM> may use for beamforming in its communication with UE <NUM>. Signals may be transmitted multiple times in different directions (e.g., each transmission may be beamformed differently). A mmW receiver (e.g., a UE <NUM>) may try multiple beams (e.g., antenna subarrays) while receiving the synchronization signals.

In some cases, the antennas of a base station <NUM> or UE <NUM> may be located within one or more antenna arrays, which may support beamforming or MIMO operation. One or more base station antennas or antenna arrays may be collocated at an antenna assembly, such as an antenna tower. A base station <NUM> may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE <NUM>.

The MAC layer may also use HARQ to provide retransmission at the MAC layer to improve link efficiency.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit (which may be a sampling period of Ts= <NUM>/<NUM>,<NUM>,<NUM> seconds). Time resources may be organized according to radio frames of length of <NUM> (Tf = 307200Ts), which may be identified by a system frame number (SFN) ranging from <NUM> to <NUM>. Each frame may include ten <NUM> subframes numbered from <NUM> to <NUM>. A subframe may be further divided into two. <NUM> slots, each of which contains <NUM> or <NUM> modulation symbol periods (depending on the length of the cyclic prefix prepended to each symbol). Excluding the cyclic prefix, each symbol contains <NUM> sample periods. In some cases the subframe may be the smallest scheduling unit, also known as a TTI. In other cases, a TTI may be shorter than a subframe (e.g., a slot or one or more symbols) or may be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs).

A resource element may consist of one symbol period and one subcarrier (e.g., a <NUM> frequency range). A resource block may contain <NUM> consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each OFDM symbol, <NUM> consecutive OFDM symbols in the time domain (<NUM> slot), or <NUM> resource elements. The number of bits carried by each resource element may depend on the modulation scheme (the configuration of symbols that may be selected during each symbol period). Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate may be.

Wireless communications system <NUM> may support operation on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), a layer, a channel, etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably herein. A UE <NUM> may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation.

An eCC may be characterized by one or more features including: wider bandwidth, shorter symbol duration, shorter TTIs, and modified control channel configuration. An eCC may also be configured for use in unlicensed spectrum or shared spectrum (where more than one operator is allowed to use the spectrum). An eCC characterized by wide bandwidth may include one or more segments that may be utilized by UEs <NUM> that are not capable of monitoring the whole bandwidth or prefer to use a limited bandwidth (e.g., to conserve power).

A shorter symbol duration is associated with increased subcarrier spacing. A device, such as a UE <NUM> or base station <NUM>, utilizing eCCs may transmit wideband signals (e.g., <NUM>, <NUM>, <NUM>, <NUM>, etc.) at reduced symbol durations (e.g., <NUM> microseconds). A TTI in eCC may consist of one or multiple symbols. In some cases, the TTI duration (that is, the number of symbols in a TTI) may be variable.

A shared radio frequency spectrum band may be utilized in an NR shared spectrum system. For example, an NR shared spectrum may utilize any combination of licensed, shared, and unlicensed spectrums, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across frequency) and horizontal (e.g., across time) sharing of resources.

For example, wireless communications system <NUM> may employ LTE License Assisted Access (LTE-LAA) or LTE Unlicensed (LTE U) radio access technology or NR technology in an unlicensed band such as the <NUM> Industrial, Scientific, and Medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations <NUM> and UEs <NUM> may employ listen-before-talk (LBT) procedures to ensure the channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band. Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, or both. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD) or a combination of both.

<FIG> illustrates an example of a wireless communications system <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with various aspects of the present disclosure. In some examples, wireless communications system <NUM> may implement aspects of wireless communications system <NUM>. Wireless communications system <NUM> may include base station <NUM>-a, UE <NUM>-a, and UE <NUM>-b. UE <NUM>-b may be an NB-IoT device with limited processing capabilities and battery life compared to UE <NUM>-a.

Base station <NUM>-a may communicate with devices inside its coverage area <NUM>-a, such as UE <NUM>-a and UE <NUM>-b. For example, base station <NUM>-a may send downlink data to UE <NUM>-a using physical downlink shared channel (PDSCH) <NUM>-a. Base station <NUM>-a may also send downlink data to UE <NUM>-b using PDSCH <NUM>-b. PDSCH <NUM>-b may be a narrowband PDSCH (nPDSCH). UE <NUM>-a and UE <NUM>-b may send an ACK to base station <NUM>-a if they correctly receive the downlink data, or a NACK to base station <NUM>-a if they incorrectly receive the downlink data. For example, UE <NUM>-a may send ACK/NACK <NUM>-a to base station <NUM>-a and UE <NUM>-b may send ACK/NACK <NUM>-b to base station <NUM>-a. Rather than sending the ACK/NACKs <NUM> according to a fixed delay, however, the UEs <NUM> may send the ACK/NACKs <NUM> according to a delay that is tailored to their ability to process the downlink data. The ability of a UE <NUM> to process downlink data may be based on the UE's design and/or the transmission parameters of the downlink data. Thus, a UE <NUM> may send an ACK/NACK according to a delay that is based on the UE's downlink processing abilities and/or based on the transmission parameters of the downlink data.

In one example, the ACK/NACK delay <NUM> used by the UEs <NUM> may accommodate their respective processing abilities and may be independent of the transmission parameters of the downlink data. For instance, UE <NUM>-a and base station <NUM>-a may determine that UE <NUM>-a can process downlink data and prepare an ACK/NACK in a given amount of time (e.g., n ms, n symbols, or n TTIs). Accordingly, UE <NUM>-a may use a delay <NUM>-a that corresponds to n ms, n symbols, or n TTIs. Similarly, base station <NUM>-a may monitor for ACK/NACKs from UE <NUM>-a based on a delay that corresponds to n ms, n symbols, or n TTIs (e.g., within the first TTI that starts no earlier than the delay from the PDSCH). Due to the more limited processing capabilities of UE <NUM>-b, UE <NUM>-b may use a delay <NUM>-b that corresponds to m ms, m symbols, or m TTIs, where m is greater than n.

In another example, the UEs <NUM> may select delay <NUM> based on the transmission parameters associated with the downlink data. For example, the UEs <NUM> may base the durations of the delays <NUM> on the size of the transport block(s) (TB) used to convey the downlink data in the PDSCH <NUM>. Because larger transport blocks take longer to process, larger TB sizes may correspond to longer delays <NUM>. The size of a transport block may be based on the number of bits conveyed by the transport block, which can be determined from the modulation and coding scheme (MCS) of the transport block and its resource allocation (e.g., how many resource blocks are assigned to the transport block). Thus, a delay <NUM> may be based on the MCS and/or resource allocation associated with downlink data.

In some cases, the UEs <NUM> may select the delays <NUM> based on other transmission parameters, such as the code type applied to the data (e.g., Turbo code, convolution code, low-density parity check (LDPC) code, polar code etc.), the repetition level of the data, a type of HARQ retransmission combining (e.g., chase combining or incremental redundancy combining), a redundancy version (e.g., initial transmission or retransmission), the number of layers used to convey the data, or a modulation format of the data. In some examples, a delay <NUM> is a function of the repetition level (e.g., longer delays for higher repetition levels). A delay <NUM> may also be based on whether the redundant versions of the data are combined before or after decoding (e.g., combining demapped codeword symbols or decoded soft bits). In some examples, a delay <NUM> is a function of the number of layers associated with the PDSCH (e.g., longer delays for more layers). Additionally or alternatively, a delay <NUM> may be a function of the transmission mode (e.g., transmit diversity, spatial multiplexing, different pilot pattern/pilot type schemes). For example, in some transmission modes (e.g., TM1, TM2), processing for at least some data symbols can begin right after the end of the data symbols whereas in other transmission modes (e.g., TM9), processing may be delayed until after a subframe because of, for example, the locations of reference signals within the subframe. Thus, shorter delays may be used for some transmission modes (e.g., TM1, TM2) and longer delays may be used for other transmission modes (e.g., TM9).

In some examples, a UE <NUM> and base station <NUM> may reference a table to determine a delay <NUM>. The table may identify different delay durations for different combinations of transmission parameters. For instance, the table may identify a delay duration of y ms when the downlink data is applied with Turbo code, has a repetition level of two, and is transmitted using TM <NUM>. In some cases, the transmission parameters may serve as an index for the table. Other parameters that can serve as an index for the table include the type of UE <NUM> (e.g., whether the UE <NUM> is an eMTC device, an NB-IoT device, an LTE device, etc.). Thus, a UE <NUM> may determine the relevant transmission parameters for a downlink data transmission and use them to select a delay duration from the table. In some examples, a table indexed by parameters such as type of code, repetition level, HARQ combining type, number of layers, and/or TM provides a factor that is applied to a delay determined by TB size. The resulting delay may be rounded up to provide the delay in ms, symbols, or TTIs, for example.

In some examples, a UE <NUM> may indicate to base station <NUM>-a that the UE <NUM> will use a particular delay <NUM> indefinitely (e.g., until the UE <NUM> sends an update changing the delay <NUM>). In other cases, the UE <NUM> may inform base station <NUM>-a about the UE's processing capabilities so that the base station <NUM>-a can determine when to expect, or monitor for, an ACK/NACK from the UE <NUM>. The processing capabilities of the UE <NUM> change when the battery power of the UE <NUM> changes, when the applications running on the UE <NUM> change, or when the UE <NUM> is participating in other concurrent communications.

<FIG> illustrates an example of HARQ process <NUM> that support physical shared channel transmission to acknowledgement delay optimization in accordance with various aspects of the present disclosure. In some examples, HARQ processes <NUM> may be implemented by wireless communications system <NUM>. HARQ processes <NUM> may be examples of communications between a base station <NUM> and a UE <NUM> as described with reference to <FIG>. HARQ processes <NUM> can be used for communications in LTE, NR, eMTC, NB-IoT, etc. HARQ processes <NUM> may include physical downlink control channel (PDCCHs) transmissions <NUM>, PDSCH transmissions <NUM>, and ACK/NACKs <NUM>.

A base station <NUM> with data for a UE <NUM> may schedule a downlink transmission to the UE <NUM> using a PDCCH transmission <NUM>. For example, the base station <NUM> may schedule the data in three PDSCH transmissions <NUM>. The PDCCH transmission <NUM> may indicate to the UE <NUM> that one or more upcoming PDSCH transmissions <NUM> include data for the UE <NUM> and may inform the UE <NUM> where to find (e.g., in time and frequency) that data in the PDSCH transmissions <NUM>. For example, PDCCH transmission <NUM>-a may indicate to the UE <NUM> that PDSCH transmission <NUM>-a includes data for the UE <NUM> in certain specified time/frequency resources. A PDCCH transmission <NUM> may also include information about transmission parameters associated with the data. For example, a PDCCH transmission <NUM> may indicate the MCS and resource blocks assigned to the data, the level of repetition, the number of layers, the transmission mode, and/or the code type associated with the data.

After receiving a PDSCH transmission <NUM>, the UE <NUM> may send an ACK/NACK <NUM> (e.g., ACK/NACK <NUM>-a) to the base station <NUM> (e.g., the UE <NUM> may send an ACK if the UE <NUM> is able to successfully process the data and a NACK if the UE <NUM> is unable to successfully process the data). In some cases, the UE <NUM> may send the ACK/NACK <NUM> after a fixed delay <NUM> (e.g., a default delay of <NUM> for NB-IoT devices). For example, in HARQ process <NUM>-a, the UE <NUM> may send each ACK/NACK <NUM> according to fixed delay <NUM>, regardless of the processing capabilities of the UE <NUM> and irrespective of the transmission parameters associated with the PDSCH transmission <NUM>. When a fixed delay <NUM> is used, the UE <NUM> may not enter low power mode (e.g., sleep mode or idle mode) until time <NUM>.

According to the techniques described herein, a UE <NUM> employs adaptable ACK/NACK delays. Adaptable ACK/NACK delays may enable the UE to spend more time in low power mode or increase efficiency of communications. For example, a UE <NUM> may employ HARQ process <NUM>-b, in which the delay <NUM> is less than the fixed delay <NUM>. By reducing the duration of delay <NUM>, relative to delay <NUM>, the UE <NUM> may enter sleep mode at <NUM>, rather than at <NUM>. The UE <NUM> selects the delay <NUM> based on the processing capabilities of the UE <NUM> and the delay <NUM> may be the same for multiple ACK/NACKs <NUM>. For example, the UE <NUM> may determine that it can process downlink data and prepare a corresponding ACK/NACK <NUM> within n ms, n symbols, or n TTIs, regardless of the transmission parameters of the PDSCH transmission <NUM>. The UE <NUM> may select a delay <NUM> to be used indefinitely based on the processing capabilities of the UE <NUM> (e.g., based on the n ms n symbols, or n TTIs). The UE <NUM> may send an indication of the delay <NUM> to the base station <NUM>, which can leverage that information to determine when to monitor for ACK/NACKs <NUM>. The processing capabilities of the UE <NUM> change over time (i.e., the processing capabilities fluctuate with battery power or based on other enabled features or concurrent communications). To accommodate such changes, the UE <NUM> may re-evaluate its processing capabilities and sends an update to the base station <NUM> indicating the changes. The UE <NUM> may also update the duration of its delay <NUM> and inform the base station <NUM> of this update.

In some cases, as shown in HARQ process <NUM>-c, a UE <NUM> may select different delays for different PDSCH transmissions <NUM>. The delays may be selected based on the transmission parameters of the data for each corresponding PDSCH transmission <NUM>. For example, if the data in PDSCH transmission <NUM>-b is conveyed in a small transport block, the UE <NUM> may select a shorter delay <NUM> (compared to the default delay <NUM>) for sending the corresponding ACK/NACK <NUM>-b. The UE <NUM> may determine the transport block size based on the MCS and resource allocation conveyed in PDCCH transmission <NUM>-b. Conversely, if PDSCH transmission <NUM>-c includes a large transport block, the UE <NUM> may select a longer delay <NUM> for sending the corresponding ACK/NACK <NUM>-c. UE <NUM> may revert to using a shorter delay (e.g., delay <NUM>) for a subsequent ACK/NACK (e.g., ACK/NACK <NUM>-d) if the PDSCH transmission <NUM>-d includes a small transport block. Thus, a UE <NUM> may dynamically select different delays for sending ACK/NACKs <NUM>.

In some cases, the techniques described herein are translated to the delays between PDCCH transmissions <NUM> and PDSCH transmissions <NUM> or physical uplink shared channel (PUSCH) transmissions. The delays may be configurable based on various parameters (e.g., a code type, a repetition level, a size of at least one transport block, a number of transmission layers, the transmission mode, MCS of the transport block, a code rate, a redundancy version of the transmission, a resource allocation size, a modulation format, a bandwidth, a number of carriers, etc.). In particular, the delay between a PDCCH transmission <NUM> and a PDSCH transmission <NUM> is configurable based on the processing capabilities of the UE <NUM> or on the PDCCH search space (e.g., longer delays may be selected for larger search spaces or larger numbers of PDCCH candidates and shorter delays may be selected for smaller search spaces or smaller numbers of PDCCH candidates). In one example, the UE <NUM> may determine its ability to process a PDCCH transmission <NUM>. Based on its ability, UE <NUM> selects a delay duration that a base station <NUM> should use between PDCCH transmissions <NUM> and PDSCH transmissions <NUM>. For example, a default delay for PDCCH to PDSCH delay for NB-IoT communications may be <NUM>, but a UE capable of eMTC communications may be able to support a delay of <NUM>. Thus, the UE <NUM> may indicate to the base station <NUM> that it can support a <NUM> delay for PDCCH to PDSCH delay. Alternatively, the UE <NUM> may send its processing capabilities to the base station <NUM> and the base station <NUM> may select a PDCCH-to-PDSCH delay that accommodates the processing capabilities of the UE <NUM>.

The delay between a PDCCH transmission and a PUSCH transmission is configurable based on the processing capabilities of the UE <NUM>, on the PDCCH search space size, on the number of PDCCH candidates, on transmission parameters (e.g., TB size, code type, code rate, repetition level, number of layers, redundancy version, MCS, resource allocation, transmission mode, carrier bandwidth, number of carriers, etc.), or on a combination of these factors. For example, the UE <NUM> may send a message to the base station <NUM> indicating a processing capability for the PDCCH search space or PUSCH encoding, and the base station <NUM> and UE <NUM> may each determine the PDCCH to PUSCH delay based on the processing capability, the PDCCH search space size, number of PDCCH candidates, and/or transmission parameters associated with the PUSCH transmission. For example, the UE <NUM> may determine that it can process uplink data and prepare a corresponding PUSCH within n ms, n symbols, or n TTIs, regardless of the transmission parameters of the PUSCH transmission. The UE <NUM> selects a delay to be used indefinitely based on the processing capabilities of the UE <NUM> (e.g., based on the n ms n symbols, or n TTIs). The UE <NUM> may send an indication of the delay to the base station <NUM>, which can leverage that information to determine when to monitor for the PUSCH transmission. The processing capabilities of the UE <NUM> change over time (i.e., the processing capabilities fluctuate with battery power or based on other enabled features or concurrent communications). To accommodate such changes, the UE <NUM> may re-evaluate its processing capabilities and sends an update to the base station <NUM> indicating the changes. The UE <NUM> may also update the duration of its delay and inform the base station <NUM> of this update.

Additionally or alternatively, the timing between an uplink transmission such as an ACK/NACK or PUSCH transmission and a subsequent PDCCH from the base station may be adaptable based on UE capabilities. For example, a guard period of <NUM> may be used for retuning (e.g., for a half-duplex UE). Some UEs (e.g., UEs capable of full-duplex communications) may not require a guard period, and some UEs may be able to retune with a shorter delay (e.g., within a few symbols). Where the PDCCH starts after the start of the subframe, the UEs may be able to receive PDCCH in a subframe immediately following a subframe where the UE transmitted ACK/NACK or PUSCH. The UE may indicate its capabilities related to uplink transmission such as an ACK/NACK or PUSCH transmission and subsequent PDCCH transmission to the base station <NUM>. Additionally or alternatively, the timing between an uplink transmission such as an ACK/NACK or PUSCH transmission and a subsequent PDCCH may depend on transmission parameters associated with the PUSCH transmission. For example, a UE may be unable to maintain other processing threads when a subsequent PDCCH directly or quickly follows a PUSCH or ACK/NACK. Thus, the UE <NUM> may report a capability for ACK/NACK or PUSCH transmission to PDCCH timing to allow for sharing of processing capabilities with other threads maintained by the UE. The ACK/NACK or PUSCH transmission to PDCCH timing may also be based on the PUSCH transmission parameters, as discussed above for PDCCH to PUSCH timing.

<FIG> illustrates an example of a HARQ process <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with various aspects of the present disclosure. HARQ process <NUM> may be implemented by a UE <NUM> and base station <NUM>. HARQ process may include a PDCCH transmission <NUM>, PDSCH transmission(s) <NUM>, and ACK/NACK transmission(s) <NUM>.

A base station <NUM> may send a PDCCH transmission <NUM> to a UE <NUM>. The PDCCH transmission <NUM> may be sent in a TTI (e.g., TTI N). The PDCCH transmission <NUM> may indicate an upcoming PDSCH transmission <NUM> for the UE <NUM> and/or the transmission parameters for that PDSCH transmission <NUM>. For example, the PDCCH transmission <NUM> may indicate that the upcoming PDSCH transmission <NUM> is in TTI N+<NUM>. The PDCCH transmission <NUM> may indicate the number of layers and/or code type used for the PDSCH transmission <NUM>. Additionally or alternatively, the PDCCH transmission <NUM> may indicate the MCS and/or resource allocation for the PDSCH transmission <NUM>. In some examples, the UE <NUM> may determine the transmission mode of the PDSCH transmission <NUM> (e.g., the UE <NUM> may be configured to operate in a TM via RRC signaling).

The UE <NUM> may receive the PDCCH transmission <NUM> in TTI N and determine which resources of the PDSCH transmission <NUM> convey data for the UE <NUM>. The UE <NUM> may also determine the transmission parameters for the PDSCH transmission <NUM>. Although PDCCH transmission <NUM> and PDSCH transmission <NUM> are shown in different TTIs, in some cases PDCCH transmission <NUM> and PDSCH transmission <NUM> may be transmitted/received in the same TTI. After receiving the PDSCH transmission <NUM> in TTI N+<NUM>, the UE <NUM> may send an ACK/NACK <NUM> to the base station <NUM> in TTI(s) selected by the UE <NUM>. The UE <NUM> may select the TTI(s) from multiple TTIs that it knows the base station <NUM> will monitor. For example, the base station <NUM> may monitor for the ACK/NACK <NUM> in a first TTI associated with a first delay (e.g., <NUM> TTIs after TTI N+<NUM>), a second TTI associated with a second delay (e.g., <NUM> TTIs after TTI N+<NUM>), and a third TTI associated with a third delay (e.g., <NUM> TTIs after TTI N+<NUM>). The UE may select a subset of the monitored TTIs for transmission (e.g., repetitions) of ACK/NACK <NUM>. The base station <NUM> and UE <NUM> may determine the opportunities (e.g., TTIs) for ACK/NACK signaling based on the transmission parameters of the downlink transmission as discussed above. For example, each of the first, second, and third delays may be based on UE capability and/or transmission parameters such as TB size, type of code, repetition level, HARQ combining type, number of layers, and/or TM. Thus, the UE <NUM> may have several opportunities (e.g., TTIs) to transmit the ACK/NACK <NUM>, each of which is associated with a different delay. For example, TTI N+<NUM> may be associated with a short delay (e.g., <NUM> TTIs), TTI N+<NUM> may be associated with a medium delay (e.g., <NUM> TTIs), and TTI N+<NUM> may be associated with a long delay (e.g., <NUM> TTIs). Based on the actual processing time (e.g., completion of decoding and error checking, etc.), the UE <NUM> may select one or more of the available TTIs monitored by the base station <NUM> for ACK/NACK <NUM>. In some examples, UE <NUM> may reference a table to select the opportunities for ACK/NACK <NUM> (e.g., the table may define different delays for different combinations of transmission parameters as discussed above).

In some examples, the PDSCH transmission <NUM> may be associated with a repetition level (e.g., communicated via the PDCCH transmission <NUM> or semi-statically for each PDSCH transmission via RRC). For example, the PDCCH transmission <NUM> may indicate that data in PDSCH transmission <NUM> will be sent twice: once in PDSCH transmission <NUM> (e.g., once in TTI N+<NUM>) and again in PDSCH transmission <NUM>-a (e.g., in a subsequent TTI). The UE <NUM> may combine the signals from both PDSCH transmissions <NUM> to increase the likelihood of successfully recovering the data conveyed by the PDSCH transmissions <NUM>. The UE <NUM> may combine the signals prior to or after decoding (e.g., combining demapped symbols or soft bits). In some cases, the UE <NUM> may select the PDSCH-to-ACK/NACK delay based on whether the UE <NUM> combines the signals prior to decoding or after decoding.

When multiple PDSCH transmissions <NUM> are transmitted with redundant versions of data, the UE <NUM> may send a single ACK/NACK <NUM> to indicate the receipt status of one or both PDSCH transmissions <NUM>. For instance, the UE <NUM> may send ACK/NACK <NUM> in TTI N+<NUM> to indicate the receipt status of PDSCH transmission <NUM> and/or PDSCH transmission <NUM>-a and the UE <NUM> may repeat ACK/NACK <NUM> in TTI N+<NUM> as shown by ACK/NACK <NUM>-a. The delay between the PDSCH transmission <NUM> and ACK/NACK <NUM> may be selected based on the repetition level of the data conveyed by the PDSCH transmissions <NUM>.

<FIG> illustrates an example of a process flow <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with various aspects of the present disclosure. In some examples, aspects of process flow <NUM> may be implemented by wireless communications system <NUM>. Process flow <NUM> may involve base station <NUM>-b and UE <NUM>-b. In some cases, UE <NUM>-b may be an NB-IoT device. Aspects of process flow <NUM> may be used to select a PDSCH-to-ACK delay that is based on the transmission parameters associated with a PDSCH. Prior to <NUM>, UE <NUM>-b may establish a connection with base station <NUM>-b and monitor control channels associated with the base station <NUM>-b. Although described with reference to PDSCH-to-ACK delay, aspects of process flow <NUM> may be used for PDSCH-to-NACK delay.

At <NUM>, base station <NUM>-b may send, and UE <NUM>-b may receive, a downlink scheduling grant. The scheduling grant may indicate an upcoming downlink transmission that includes data for UE <NUM>-b from base station <NUM>-b (e.g., the scheduling grant may be a PDCCH transmission and may indicate an upcoming PDSCH transmission). In some cases, the scheduling grant may also include transmission parameters for the upcoming downlink transmission (e.g., repetition level, number of layer, MCS, resource allocation, redundancy version, transmission mode, code type, code rate, etc.). At <NUM>, UE <NUM>-b may determine the transmission parameters for the downlink transmission and/or the data. The transmission parameters may be received directly from base station <NUM>-b and/or determined based on the transmission parameters sent from base station <NUM>-b (e.g., UE <NUM>-b may identify the size of the transport block(s) used to convey the data based on the MCS and resource allocation indicated in the scheduling grant). UE <NUM>-b may also determine the time and frequency resources used to convey the data.

At <NUM>, base station <NUM>-b may send, and UE <NUM>-b may receive, a downlink data transmission. For instance, base station <NUM>-b may send data to UE <NUM>-b in PDSCH (e.g., in a first TTI). At <NUM>, UE <NUM>-b may process the data in the downlink transmission. After determining that the data has been successfully processed, UE <NUM>-b may, at <NUM>, identify resources (e.g., time and frequency resources) for sending an ACK to base station <NUM>-b. For example, UE <NUM>-b may identify a TTI for sending the ACK. The TTI may be selected based on a delay, which in turn may be selected based on the transmission parameters of the downlink data transmission. For example, if the PDSCH conveyed the data in a small transport block, UE <NUM>-b may select a short delay for sending the ACK. If the PDSCH conveyed the data in a large transport block, UE <NUM>-b may select a long delay for sending the ACK. In some examples the delay may be proportional (e.g., linearly proportional) to the size of the transport block(s) used to convey the data. Thus, the delay may be based on transmission parameters that affect the processing time of the data.

In some cases, UE <NUM>-b may select a first delay that is based on one transmission parameter (e.g., non-TB-size dependent delay such as a delay based on the processing capabilities of UE <NUM>-b) and a second, TB size dependent delay. In such a scenario, UE <NUM>-b may add the first delay and the second delay together to create a new delay, which the UE <NUM>-b may use in selecting the TTI for transmitting the ACK. In some cases, UE <NUM>-b may select either the first delay or the second delay (e.g., whichever is longer) to use in selecting the TTI from transmitting the ACK.

At <NUM>, UE <NUM>-b may send the ACK to base station <NUM>-b using the resources selected at <NUM> (e.g., during the selected TTI). Base station <NUM>-b may monitor for, and receive, the ACK at <NUM>. Base station <NUM>-b may determine when to monitor for the ACK based on the transmission parameters associated with the downlink data. For example, when the downlink data is conveyed by a small transport block the base station <NUM>-b may decide to monitor for the ACK after a short delay (relative to a delay used when the downlink data is conveyed by a comparatively larger transport block). In some cases, base station <NUM>-b may monitor for the ACK a number of times (e.g., base station <NUM>-b may monitor for the ACK in several different TTIs).

<FIG> illustrates an example of a process flow <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with various aspects of the present disclosure. In some examples, aspects of process flow <NUM> may be implemented by wireless communications system <NUM>. Process flow <NUM> may involve base station <NUM>-c and UE <NUM>-c. In some cases, UE <NUM>-b may be an NB-IoT device. Aspects of process flow <NUM> may be used to select a PDSCH-to-ACK delay that is based on the processing capabilities of UE <NUM>-c. Prior to <NUM>, UE <NUM>-c may establish a connection with base station <NUM>-c and monitor control channels associated with the base station <NUM>-c. Although described with reference to PDSCH-to-ACK delay, aspects of process flow <NUM> may be used for PDSCH-to-NACK delay.

At <NUM>, UE <NUM>-c may determine its processing capabilities (e.g., by evaluating its hardware configuration, other processing tasks, and/or battery level to determine its processing capabilities). At <NUM>, UE <NUM>-c may transmit an indication of its processing capabilities to base station <NUM>-c. In some cases, UE <NUM>-c may indicate that it is able to transmit ACK with a delay that is shorter than the default delay for transmitting ACK. In some cases, UE <NUM>-c may indicate that it is able to transmit ACK within a delay window (e.g., UE <NUM>-c may indicate a maximum delay supported by UE <NUM>-c). In some cases, UE <NUM>-c may indicate a transport block size dependent processing capability (e.g., UE <NUM>-c may indicate that it takes n ms to process x bits of a transport block). In some cases, UE <NUM>-c may indicate to base station <NUM>-c the delay at which UE <NUM>-c will send ACK. In such cases, UE <NUM>-c may also indicate whether that delay will be used indefinitely (e.g., until UE <NUM>-c changes it and updates base station <NUM>-c) or for a number of ACKs.

At <NUM>, base station <NUM>-c may send, and UE <NUM>-c may receive, a scheduling grant (e.g., PDCCH). The scheduling grant may include the transmission parameters for data conveyed by an upcoming PDSCH. At <NUM>, base station <NUM>-c may determine a delay for ACK (e.g., a delay between sending the data and receiving the ACK). Base station <NUM>-c may determine the delay based on the processing capabilities indicated by UE <NUM>-c and/or the transmission parameters of the data. In some cases, base station <NUM>-c may determine a number of TTIs to monitor for the ACK (e.g., based on the determined delay, the processing capabilities of UE <NUM>-c, or the transmission parameters of the data). In one example, base station <NUM>-c may determine that the downlink transmission will convey the data in y transport block units and that UE <NUM>-c can process x transport block units in n ms. Using this information, base station <NUM>-c may calculate how long it will take UE <NUM>-c to process the downlink transmission and determine the ACK/NACK delay accordingly. At <NUM>, base station <NUM>-c may send, and UE <NUM>-c may receive, a downlink message conveying data for UE <NUM>-c (e.g., PDSCH). At <NUM>, UE <NUM>-c may successfully process the downlink message and make a determination to send an ACK.

At <NUM>, UE <NUM>-c may determine a delay for transmitting an ACK corresponding to the downlink data transmission. UE <NUM>-c may determine the delay based on its processing capabilities and/or based on the transmission parameters of the downlink data transmission. A TTI for the ACK may be selected based on the delay. At <NUM>, UE <NUM>-c may transmit the ACK corresponding to the downlink data transmission (e.g., the ACK may be send in the TTI that was selected based on the delay). At <NUM>, base station <NUM>-c may monitor for and receive the ACK from UE <NUM>-c.

<FIG> shows a block diagram <NUM> of a wireless device <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a UE <NUM> as described herein. Wireless device <NUM> may include receiver <NUM>, communications manager <NUM>, and transmitter <NUM>. Wireless device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

Receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to physical shared channel transmission to acknowledgement delay optimization, etc.). In some cases, receiver <NUM> may receive a downlink scheduling grant (e.g., included in a PDCCH transmission from a base station <NUM>) indicating an upcoming downlink data transmission. In some cases, receiver <NUM> may receive a downlink transmission (e.g., a PDSCH transmission) corresponding to the downlink scheduling grant. The downlink transmission may be received in a first TTI. In some cases, receiver <NUM> may receive a scheduling grant at the wireless device <NUM> in a first TTI from a base station <NUM>. Information received by receiver <NUM> may be passed on to other components of the wireless device <NUM>. For example, receiver <NUM> may pass a representation of a received signal (e.g., signal representation <NUM>) on to communications manager <NUM>. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>. The receiver <NUM> may utilize a single antenna or a set of antennas.

Communications manager <NUM> may receive a downlink scheduling grant (e.g., in a PDCCH transmission) from a base station <NUM>. The downlink scheduling grant may indicate an upcoming downlink transmission from the base station <NUM> (e.g., the grant may indicate an upcoming PDSCH transmission). Communications manager <NUM> may receive the downlink transmission from the base station <NUM> in a first TTI. The downlink transmission may be associated with a transmission mode and may include at least one transport block over at least one transmission layer. Communications manager <NUM> may identify a second TTI for sending an ACK. The second TTI may be identified based on the transmission parameter(s) associated the data. In some cases, the transmission parameters are associated with the transport block, transmission layer, or transmission mode or the downlink transmission. After the second TTI is identified, communications manager <NUM> may send an ACK of the received data to the base station <NUM> during the second TTI.

The communications manager <NUM> identifies a capability of the wireless device <NUM> to process transmissions. The communications manager <NUM> transmits to a base station <NUM> an indication of the wireless device's capability to process transmissions. After transmitting the indication, the communications manager <NUM> receives a first physical channel transmission from the base station <NUM> in a first TTI. The communications manager <NUM> communicates a second physical channel transmission with the base station in a second TTI. The second TTI is determined based on the first TTI and the indicated capability of the wireless device to process transmissions. In some cases, the first physical channel transmission comprises a PDSCH transmission and communicating the second physical channel transmission comprises transmitting an ACK message for the PDSCH transmission. In some cases, the first physical channel transmission comprises a PDCCH transmission and communicating the second physical channel transmission comprises receiving a PDSCH transmission. In some cases, the first physical channel transmission comprises a PDCCH transmission and communicating the second physical channel transmission comprises transmitting a PUSCH transmission.

In some cases, the communications manager <NUM> may receive a scheduling grant at the wireless device <NUM> in a TTI. The communications manager <NUM> may receive the scheduling grant from a base station <NUM>. The scheduling grant may indicate resources for communicating a transmission with the base station <NUM>. The transmission may be transmitted with a certain transmission mode and the transmission may be comprised of one or more transport blocks over one or more transmission layers. The communications manager <NUM> may identify a second TTI for a transmission. The second TTI may be identified based on the first TTI, and one or more transmission parameters associated with the one or more transport blocks, at least one transmission layer, or the transmission mode. For example, the second TTI may be identified based on an MCS of the at least one transport block, a code rate, a redundancy version, a resource allocation size, a modulation format, a bandwidth, or a number of carriers of the downlink transmission. The communications manager <NUM> may also communicate the transmission during the second TTI.

Communications manager <NUM> may pass information on to other components of wireless device <NUM>. For example, communications manager <NUM> may pass to transmitter <NUM> an indication <NUM> of when to send an ACK. Communications manager <NUM> may be an example of aspects of the communications manager <NUM> described with reference to <FIG>.

The communications manager <NUM> and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions of the communications manager <NUM> and/or at least some of its various sub-components may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager <NUM> and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, communications manager <NUM> and/or at least some of its various sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, communications manager <NUM> and/or at least some of its various sub-components may be combined with one or more other hardware components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

In some cases, transmitter <NUM> may transmit an indication of the wireless device's ability to process downlink transmissions. In some cases, transmitter <NUM> may transmit an ACK to a base station <NUM>. The ACK may be sent in a TTI identified by the wireless device <NUM>. The TTI may be based on the wireless device's ability to process downlink transmissions. In some cases, transmitter <NUM> may communicate a transmission during a second TTI. In some cases, transmitter <NUM> may transmit, to the base station <NUM>, a second indication of the wireless device's <NUM> capability to process transmissions. The second indication indicates or reflects a change in the wireless device's <NUM> capability to process transmissions.

<FIG> shows a block diagram <NUM> of a wireless device <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a wireless device <NUM> or a UE <NUM> as described with reference to <FIG>. Wireless device <NUM> includes receiver <NUM>, communications manager <NUM>, and transmitter <NUM>. Wireless device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

Receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to physical shared channel transmission to acknowledgement delay optimization, etc.). Information may be passed on to other components of the device. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>. The receiver <NUM> may utilize a single antenna or a set of antennas.

Communications manager <NUM> may include scheduling administrator <NUM>, downlink manager <NUM>, ACK delay manager <NUM>, ACK transmission coordinator <NUM>, UE capability manager <NUM>, and capability signaler <NUM>. Communications manager <NUM> may be an example of aspects of the communications manager <NUM> described with reference to <FIG>.

Scheduling administrator <NUM> may receive a downlink scheduling grant (e.g., a PDCCH transmission) from a base station <NUM>. The downlink scheduling grant may indicate an upcoming downlink transmission (e.g., a PDSCH transmission) from the base station <NUM>. Scheduling administrator <NUM> may process the grant to determine the resources and transmission parameters of the upcoming downlink transmission. For example, scheduling administrator <NUM> may identify a code type of the downlink transmission, a repetition level of the downlink transmission, a transport block size of the downlink transmission, a number of transmission layers in the downlink transmission, the transmission mode, an MCS of the at least one transport block, a code rate, a redundancy version, a resource allocation size, a modulation format, a bandwidth, or a number of carriers, of the downlink transmission. In some cases, scheduling administrator <NUM> may select a delay between a received scheduling grant and a second TTI for a transmission, wherein the second TTI is selected based at least in part on a first TTI and one or more transmission parameters associated with the at least one transport block, the at least one transmission layer, or the transmission mode. For example, the second TTI may be identified based at least in part on an MCS of the at least one transport block, a code rate of the downlink transmission, a redundancy version of the downlink transmission, a resource allocation size, a modulation format, a bandwidth, or a number of carriers of the downlink transmission. Additionally or alternatively, scheduling administrator <NUM> may select the delay based on PDCCH search space size or number of PDCCH candidates.

Downlink manager <NUM> may receive downlink data transmissions from a base station <NUM>. For example, downlink manager <NUM> may receive a downlink transmission from the base station <NUM> in a first TTI. The downlink transmission may be associated with a transmission mode and may include at least one transport block over at least one transmission layer.

ACK delay manager <NUM> may identify TTIs for sending ACKs. For example, ACK delay manager <NUM> may identify a TTI for sending an acknowledgement of data conveyed by the downlink transmission. In some cases, identifying the TTI includes selecting a delay from a table that identifies different delays for different combinations of transmission parameters. In some cases, identifying the second TTI includes identifying a set of TTIs during which the base station will be monitoring for the ACK based on the one or more transmission parameters. In some cases, the TTI is identified based on one or more transmission parameters associated with the downlink transmission (e.g., transport block size, number of transmission layers, transmission mode, etc.). Thus, ACK delay manager <NUM> may select a delay for sending the ACK based on the transmission parameters of the downlink transmission. In some cases, the selected delay is proportional to the size of the at least one transport block. In some cases, ACK delay manager <NUM> may select the ACK TTI(s) from a set of TTIs based on a UE capability to process downlink transmissions.

ACK transmission coordinator <NUM> may coordinate ACK transmissions for wireless device <NUM>. For example, ACK transmission coordinator <NUM> may send an ACK to the base station <NUM> during the TTI(s) selected by ACK delay manager <NUM>. UE capability manager <NUM> may identify the downlink processing capabilities of wireless device <NUM>. For example, UE capability manager <NUM> may identify the capability of the wireless device <NUM> to process downlink transmissions. Further, UE capability manager <NUM> detects or determines a change in the capability of the wireless device <NUM> to process transmissions. In some cases, UE capability manager <NUM> may determine an ability by the wireless device <NUM> to process scheduling grants. In some cases, UE capability manager <NUM> may identify at least one of a code type, a repetition level, a size of the at least one transport block, a modulation and coding scheme (MCS) of the at least one transport block, a number of transmission layers in the at least one transmission layer, the transmission mode, an MCS of the at least one transport block, a code rate, a redundancy version, a resource allocation size, a modulation format, a bandwidth, or a number of carriers associated with a transmission.

Capability signaler <NUM> may manage the communication of the wireless device's <NUM> capabilities. For example, capability signaler <NUM> may transmit, to a base station <NUM>, an indication of the wireless device's <NUM> capability to process downlink transmissions. In some cases, the indication of the wireless device's <NUM> capability to process transmissions indicates that the wireless device <NUM> is able to transmit the ACK message with a transmission delay that is smaller than a default transmission delay for transmitting ACK messages. In some cases, the indication of the wireless device's <NUM> capability to process transmissions comprises a maximum ACK delay value supported by the wireless device <NUM>. In some cases, the indication of the wireless device's <NUM> capability to process transmissions includes a maximum ACK delay value supported by the wireless device <NUM>. In some cases, the indication of the wireless device's <NUM> capability to process transmissions indicates a processing capability of the wireless device <NUM> associated with one or more transport block sizes, a processing capability of the wireless device <NUM> associated with a number of transmission layers, a processing capability of the wireless device <NUM> associated with one or more transmission modes, or a combination thereof. In some cases, the indication of the wireless device's <NUM> capability to process transmissions indicates a capability of the wireless device <NUM> to encode the PUSCH transmission.

<FIG> shows a diagram of a system <NUM> including a device <NUM> that supports physical shared channel transmission to acknowledgement delay optimization in accordance with aspects of the present disclosure. Device <NUM> may be an example of or include the components of wireless device <NUM>, wireless device <NUM>, or a UE <NUM> as described above, e.g., with reference to <FIG> and <FIG>. Device <NUM> may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including communications manager <NUM>, processor <NUM>, memory <NUM>, software <NUM>, transceiver <NUM>, antenna <NUM>, and I/O controller <NUM>. These components may be in electronic communication via one or more buses (e.g., bus <NUM>). Device <NUM> may communicate wirelessly with one or more base stations <NUM>.

Processor <NUM> may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor <NUM> may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor <NUM>. Processor <NUM> may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting physical shared channel transmission to acknowledgement delay optimization).

Software <NUM> may include code to implement aspects of the present disclosure, including code to support physical shared channel transmission to acknowledgement delay optimization. Software <NUM> may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software <NUM> may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

<FIG> shows a flowchart illustrating a method <NUM> for physical shared channel transmission to acknowledgement delay optimization in accordance with aspects of the present disclosure. The operations of method <NUM> may be implemented by a UE <NUM> or its components as described herein. For example, the operations of method <NUM> may be performed by a communications manager as described with reference to <FIG> and <FIG>. In some examples, a UE <NUM> may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE <NUM> may perform aspects of the functions described below using special-purpose hardware.

At block <NUM> the UE <NUM> may receive a downlink scheduling grant from a base station. The downlink scheduling grant may indicate an upcoming downlink transmission from the base station. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a scheduling administrator as described with reference to <FIG>.

At block <NUM> the UE <NUM> may receive the downlink transmission from the base station in a first TTI. The downlink transmission may be associated with a transmission mode and may comprise at least one transport block over at least one transmission layer. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a downlink manager as described with reference to <FIG>.

At block <NUM> the UE <NUM> may identify a second TTI for sending an acknowledgement of data conveyed by the downlink transmission. The second TTI may be identified based at least in part on the first TTI and one or more transmission parameters associated with the at least one transport block, the at least one transmission layer, or the transmission mode. For example, the second TTI may be identified based at least in part on an MCS of the at least one transport block, a code rate, a redundancy version, a resource allocation size, a modulation format, a bandwidth, or a number of carriers of the downlink transmission. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a ACK delay manager as described with reference to <FIG>.

At block <NUM> the UE <NUM> may send an acknowledgement of the data to the base station during the second TTI. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a ACK transmission coordinator as described with reference to <FIG>.

<FIG> shows a flowchart illustrating a method <NUM> for physical shared channel transmission to acknowledgement delay optimization in accordance with aspects of the present disclosure. The operations of method <NUM> is implemented by a UE <NUM> or its components as described herein. For example, the operations of method <NUM> may be performed by a communications manager as described with reference to <FIG> and <FIG>. In some examples, a UE <NUM> may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE <NUM> may perform aspects of the functions described below using special-purpose hardware.

At block <NUM> the UE <NUM> identifies, by a UE, a capability of the UE to process transmissions. The operations of block <NUM> are performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a UE capability manager as described with reference to <FIG>.

At block <NUM> the UE <NUM> transmits, to a base station, an indication of the UE's capability to process transmissions. The operations of block <NUM> are performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a capability signaler as described with reference to <FIG>.

At block <NUM> the UE <NUM> receives a first physical channel transmission from the base station in a first TTI. The operations of block <NUM> are performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a scheduling administrator as described with reference to <FIG>.

At block <NUM> the UE <NUM> communicates a second physical channel transmission with the base station in a second TTI. The second TTI is determined based on the first TTI and the indicated capability of the UE to process transmissions. The operations of block <NUM> are performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a ACK transmission coordinator as described with reference to <FIG>.

At block <NUM> the UE <NUM> may receive a scheduling grant from a base station in a first TTI. The scheduling grant may indicate resources for communicating a transmission with the base station. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a receiver <NUM> as described with reference to <FIG>.

At block <NUM> the UE <NUM> may identify a second TTI for the transmission. The second TTI may be identified based on the first TTI and one or more transmission parameters associated with the a transport block, a transmission layer, or a transmission mode. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a scheduling administrator <NUM> as described with reference to <FIG>.

At block <NUM> the UE <NUM> may communicate a transmission during a second TTI. The operations of block <NUM> may be performed according to the methods described herein. In certain examples, aspects of the operations of block <NUM> may be performed by a transmitter <NUM> as described with reference to <FIG>.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA), time division multiple access.

(TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. A code division multiple access (CDMA) system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-<NUM>, IS-<NUM>, and IS-<NUM> standards.

In LTE/LTE-A networks, including such networks described herein, the term evolved node B (eNB) may be generally used to describe the base stations. The wireless communications system or systems described herein may include a heterogeneous LTE/LTE-A or NR network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB, next generation NodeB (gNB), or base station may provide communication coverage for a macro cell, a small cell, or other types of cell. The term "cell" may be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context.

Base stations may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, eNodeB (eNB), gNB, Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area for a base station may be divided into sectors making up only a portion of the coverage area. The wireless communications system or systems described herein may include base stations of different types (e.g., macro or small cell base stations). The UEs described herein may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like. There may be overlapping geographic coverage areas for different technologies.

Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of') indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

By way of example, and not limitation, non-transitory computer-readable media may comprise RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

Claim 1:
A method (<NUM>) for wireless communication, the method comprising:
identifying (<NUM>), by a user equipment, UE, a change in current capability of the UE to process transmissions based on a change in the battery level of the UE or other concurrent communications of the UE;
transmitting (<NUM>), to a base station, an indication of the change in the UE's current capability to process transmissions, wherein the indication of the change in the UE's current capability relates to one of:
a change in a current delay at which the UE will send an ACK/NACK after a PDSCH or a change in a current delay at which a PDSCH or PUSCH will be communicated after a PDCCH;
receiving (<NUM>) a first physical channel transmission from the base station in a first transmission time interval, TTI; and
communicating (<NUM>) a second physical channel transmission with the base station in a second TTI, wherein the second TTI is determined based on the first TTI and the indicated change in current capability of the UE to process transmissions.