Hybrid automatic repeat request synchronization for reduced transmission time intervals.

Description

CROSS-REFERENCES

[001] This Patent Application claims priority to Patent Application No. 15 / 444,875 - USA, entitled "Hybrid Automatic Repeat Request Synchronization for Reduced Transmission Time Intervals," filed on February 28, 2017, and to Provisional Patent Application No. 62 / 315,601 - USA, entitled "Hybrid Automatic Repeat Request Synchronization for Reduced Transmission Time Intervals," filed on March 30, 2016, which are authored by the same authors as this application. FUNDAMENTALS

[002] The following information relates to wireless communication in general, and more specifically to hybrid auto-repeat request synchronization (HARQ) for reduced transmission time intervals (TTIs).

[003] Wireless communication systems are widely used to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems may be able to sustain communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), and orthogonal frequency division multiple access (OFDMA).A wireless multiple access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, each of which may be referred to as user equipment (UE).

[004] Wireless multiple access technologies have been adopted in several telecommunications standards to provide a common protocol that allows different wireless devices to communicate at the municipal, national, regional, and even global levels. One example of a telecommunications standard is Long Term Evolution (LTE). The LTE standard was designed to improve spectral efficiency, reduce costs, enhance services, make use of new spectrum, and better integrate with other open standards. The LTE standard can utilize OFDMA in the downlink (DL), single-carrier frequency division multiple access (SC-FDMA) in the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.

[005] In an LTE system, a UE can transmit HARQ feedback information to facilitate error correction and data transmission. HARQ processing procedures can, however, create waits between receiving downlink information and transmitting HARQ feedback. These waits can result in increased latency and a decrease in overall system performance. Certain HARQ procedures may also fail to account for communications using TTIs of different durations. SUMMARY

[006] A base station can identify the capability of a user equipment (UE) to provide hybrid automatic repeat request (HARQ) for low-latency transmissions. The base station can select a HARQ synchronization mode based on the UE's capability, and the base station can indicate to the UE the selected HARQ synchronization mode. The base station can transmit one or more low-latency transmissions to the UE using TTIs of a shorter duration compared to other TTIs compatible with a system. The UE can respond with HARQ feedback based on the HARQ synchronization mode. In some cases, the HARQ synchronization mode may have distinct response times, which may be based on the location of the data transmission relative to other transmissions.

[007] A method of wireless communication is described in a system that sustains transmission time intervals (TTIs) of a first duration and a second duration that is shorter than the first duration. The method may include determining a HARQ synchronization mode based at least in part on one or more capabilities of a UE to provide HARQ feedback in response to communications using transmission time intervals (TTIs) of the second duration, as well as including communication using the HARQ synchronization mode.

[008] A wireless communication apparatus is described in a system that sustains transmission time intervals (TTIs) of a first duration and a second duration that is shorter than the first duration. The apparatus may include means for determining a HARQ synchronization mode based at least in part on one or more UE capabilities to provide HARQ feedback in response to communications using transmission time intervals (TTIs) of the second duration, as well as including means of communication using the HARQ synchronization mode.

[009] A wireless communication device is described in a system that sustains transmission time intervals (TTIs) of a first duration and a second duration that is shorter than the first duration. The device may include a processor, memory in electronic communication with the processor, and instructions stored in memory. The instructions may be operated to cause the processor to determine a HARQ synchronization mode based at least in part on one or more capabilities of a UE to provide HARQ feedback in response to communications using TTIs of the second duration, as well as to communicate using the HARQ synchronization mode.

[0010] A computer-readable non-transient medium is described that stores wireless communication code in a system that sustains transmission time intervals (TTIs) of a first duration and a second duration that is shorter than the first duration. The computer-readable non-transient medium may include instructions that cause a processor to determine a HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs and to communicate using the HARQ synchronization mode.

[0011] A computer-readable non-transient medium for wireless communication is described. The computer-readable non-transient medium may include instructions that cause a processor to determine a HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs and to communicate using the HARQ synchronization mode.

[0012] Some examples of the computer-readable methods, apparatus, and media described herein include features of, or means or instructions for receiving a first transport block (TB) during a first TTI and a second TB during a second TTI, both the first TTI and the second TTI having the second duration, and for identifying a feedback time period based at least in part on the HARQ synchronization mode, the HARQ synchronization mode possibly including a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time, and for transmitting one or more HARQ feedback messages associated with the first or second TB during the feedback time period, the HARQ feedback message or messages being received during a TTI of the first duration.

[0013] In some examples, communication includes receiving a first transport block (TB) during a first TTI and a second TB during a second TTI, both the first TTI and the second TTI having the second duration, identifying a feedback time period based at least in part on the HARQ synchronization mode, the HARQ synchronization mode encompassing a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time, and transmitting one or more HARQ feedback messages associated with the first or second TB during the feedback time period, the HARQ feedback message or messages being received during a TTI of the first duration.In some examples, the first TTI is within the final part of a first time period having the first duration, and the second TTI is within the initial part of a second time period having the first duration. Additionally or alternatively, the HARQ feedback message(s) may include a first HARQ feedback message and a second HARQ feedback message distinct from the first HARQ feedback message.

[0014] In some examples, a final portion of the first HARQ feedback message and an initial portion of the second HARQ feedback message are multiplexed using at least one of the following: a physical uplink control channel (PUCCH) format capable of carrying more than two bits, a bit split between the final portion of the first HARQ feedback message and the initial portion of the second HARQ feedback message, joint encoding of one or more bits of the first HARQ feedback message and the second HARQ feedback message, or a bit combination based at least in part on an orthogonal cover code (OCC) and at least one parity bit, or any combination thereof.

[0015] Some examples of the computer-readable methods, apparatus, and media described herein include features of, or means or instructions for transmitting an indication of one or more UE capabilities to a base station. Some examples of the computer-readable methods, apparatus, and media described herein include features of, or means or instructions for receiving an indication of a set of HARQ synchronization modes from a base station, and for transmitting a HARQ synchronization mode request in response to the indication, in which the HARQ synchronization mode is selected from the set of HARQ synchronization modes based at least in part on the HARQ synchronization mode request.

[0016] Some examples of the computer-readable methods, apparatus, and media described herein include features of, or means or instructions for, transmitting a first transport block (TB) during a first TTI and a second TB during a second TTI, both the first TTI and the second TTI having the second duration, identifying a feedback time period based at least in part on the HARQ synchronization mode, the HARQ synchronization mode encompassing a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time, and receiving one or more HARQ feedback messages associated with the first or second TB during the feedback time period, the HARQ feedback message or messages being received during a TTI of the first duration.

[0017] Some examples of the computer-readable methods, apparatus, and media described herein include features of, or means or instructions for, transmitting a first transport block (TB) during a first TTI and a second TB during a second TTI, both the first TTI and the second TTI having the second duration, identifying a feedback time period based at least in part on the HARQ synchronization mode, the HARQ synchronization mode encompassing a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time, and receiving one or more HARQ feedback messages associated with the first or second TB during the feedback time period, the HARQ feedback message or messages being received during a TTI of the first duration.

[0018] Some examples of the computer-readable methods, apparatus and media described herein include features of, or means or instructions for identifying an uplink control configuration (UL) based at least in part on the HARQ synchronization mode, and for transmitting to the UE an indication of the UL control configuration.

[0019] Some examples of the computer-readable methods, devices, and media described herein include features of, or means or instructions for identifying a first uplink control physical channel (PUCCH) resource offset for UL transmissions using first-duration TTIs and a second PUCCH resource offset for UL transmissions using second-duration TTIs. In some examples, the second PUCCH resource offset is identified based at least in part on the first PUCCH resource offset and a delta value. In some examples, the set or sets of resources for UL transmissions may be associated with each PUCCH format from a set of PUCCH formats, wherein the set or sets of resources may each be associated with a distinct base station or layer three configuration.

[0020] Some examples of the computer-readable methods, devices, and media described herein include features of, or means of, or instructions for identifying a first downlink (DL) programmed transmission indicator associated with first-duration TTIs and a second DL programmed transmission indicator associated with second-duration TTIs. In some examples, the first duration is the duration of a subframe and the second duration is the duration of a subframe storage space (slot). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 illustrates an example of a wireless communications system that supports hybrid automatic repeat request synchronization (HARQ) for reduced transmission time intervals (TTIs) in accordance with aspects of this disclosure;

[0022] FIG. 2 illustrates an example of a wireless communications system that supports HARQ synchronization for reduced TTIs according to aspects of this disclosure;

[0023] FIG.3 illustrates an example of a deporter configuration that supports HARQ synchronization for reduced TTIs in accordance with aspects of this disclosure;

[0024] FIG. 4 illustrates an example of a carrier configuration that supports HARQ synchronization for reduced TTIs in accordance with aspects of this disclosure;

[0025] FIG. 5 illustrates an example of a carrier configuration that supports HARQ synchronization for reduced TTIs in accordance with aspects of this disclosure;

[0026] FIG. 6 illustrates an example of a slot configuration that supports HARQ synchronization for reduced TTIs according to aspects of this disclosure;

[0027] FIG. 7 illustrates an example of a carrier configuration that supports HARQ synchronization for reduced TTIs in accordance with aspects of this disclosure;

[0028] FIG. 8 illustrates an example of a process flow in a system that supports HARQ synchronization for reduced TTIs according to aspects of this disclosure;

[0029] FIGS. 9 to 11 show block diagrams of a wireless device or devices supporting HARQ synchronization for reduced TTIs according to aspects of this disclosure;

[0030] FIG. 12 illustrates a block diagram of a system including a UE that supports HARQ synchronization for reduced TTIs according to aspects of this disclosure;

[0031] FIG. 13 illustrates a block diagram of a system including a base station that supports HARQ synchronization for reduced TTIs according to aspects of this disclosure; and

[0032] FIGS. 14 to 19 illustrate methods of synchronizing HARQ for reduced TTIs according to aspects of this disclosure. DETAILED DESCRIPTION

[0033] Some systems can support multiple transmission time interval (TTI) durations and can use distinct TTI durations for uplink (UL) and downlink (DL) transmissions. For example, a base station might perform DL data transmissions using a reduced TTI (e.g., a low-latency TTI such as a slot-based TTI with a duration of 0.5 ms), and a user equipment (UE) might respond with Hybrid Automatic Repeat Request (HARQ) feedback or other UL control information using a control message on a distinct (e.g., longer) duration TTI. For example, a UE might provide HARQ feedback using a legacy or non-low-latency UL transmission (e.g., a TTI with a duration of a Long-Term Evolution (LTE) subframe (i.e., 1 ms)).

[0034] The use of low-latency DL transmissions (e.g., TTIs with a duration of 0.5 ms) can enable a reduced HARQ retransmission time compared to other configurations, however the latency advantage and efficiency of a HARQ response may depend on the UE capabilities. Thus, a base station can identify the UE capability and select an appropriate HARQ synchronization mode. The HARQ synchronization mode may include a reduced response time between a DL transmission and the associated HARQ feedback, compared to other HARQ synchronization modes. In some cases, the response time may differ depending on the location of the DL transmission. For example, if a slot-duration TTI (or a "slot-TTI") is used for the DL transmission, each transport block (TB) of the DL transmission may be sent using the first slot or the second slot in a subframe.The HARQ response time for TBs sent in one slot may differ from the response time for TBs sent in the other slot.

[0035] By way of example, low-latency physical downlink shared channel (PDSCH) transmission (e.g., a PDSCH transmission mapped to a slot-duration TTI) can allow a HARQ synchronization to be shortened to a 2-slot gap or a 3-slot gap, relative to a PDSCH transmission occupying a subframe. This can allow a HARQ retransmission round trip time (RTT) of 4ms, which represents reduced latency relative to legacy LTE operation (e.g., systems operating according to older versions of LTE HARQ may have an RTT of 8ms, which can be used for non-low-latency transmission). In some examples, HARQ synchronization can be shortened to a 3-slot gap or a 4-slot gap, which can allow a HARQ RTT of 5ms.In another example, and as explained in more detail below, the response time can be the same regardless of the TTI used for DL ​​transmission, so that UL control transmissions are time-shifted (i.e., two overlapping UL control transmissions of one subframe length). In another example, HARQ synchronization for a DL slot can align with the transmission synchronization of a 1ms duration UL control message (e.g., ACK / NACK), but the HARQ RTT can be 6ms, a reduction compared to legacy operation.

[0036] Aspects of disclosure presented above are described below in the context of a wireless communication system. Additional examples of disclosure are described with reference to uplink and downlink channel configurations for low-latency HARQ feedback synchronization. Aspects of disclosure are further illustrated by and described with reference to device diagrams, system diagrams, and flow diagrams relating to HARQ synchronization for reduced TTIs.

[0037] As used herein, the terms "low latency" and "reduced latency" may refer to synchronization between transmissions (e.g., RTT) that is less than a similar operation under a legacy system or legacy version of a standard. Also, as used herein, the terms "legacy" may refer to an earlier communication technology or an earlier version of the LTE standard, which may have synchronization and operation known to experts in the field, but which do not include the reduced latency characteristics described herein. In some examples, the term "non-low latency" may be used to describe legacy operation in a system that supports both legacy operation and low or reduced latency operation, for example, in a system that supports communications using TTIs of different durations.

[0038] FIG. 1 illustrates an example of a 100 wireless communications system conforming to various aspects of this disclosure. The 100 wireless communications system includes 105 base stations, 115 UEs, and a 130 core network. In some examples, the 100 wireless communications system may be a Long Term Evolution (LTE) / LTE Advanced (LTE-A) standard network. In some examples, the 100 wireless communications system may support various HARQ synchronization modes, including modes that provide reduced RTT compared to legacy HARQ procedures.

[0039] Base stations 105 can communicate wirelessly with UEs 115 through one or more base station antennas. Each of the base stations 105 can provide communication coverage to a respective geographic coverage area 110. The communication links 125 shown in the wireless communications system 100 can include UL transmissions from a UE 115 to a base station 105, or DL ​​transmissions from a base station 105 to a UE 115. UEs 115 can be dispersed throughout the wireless communications system 100, and each UE 115 can be stationary or mobile. A UE 115 can be referred to as a mobile station, a subscriber station, a remote unit, a wireless device, an access terminal (AT), a portable device, a user agent, a client, or similar terminology.A UE 115 can also be a mobile phone, a wireless modem, a handheld device, a personal computer, a tablet, a personal electronic device, a machine-type communication (MTC) device, etc.

[0040] Base stations 105 can communicate with the central network 130, as well as with each other. For example, base stations 105 can interface with the central network 130 via backhaul links 132 (e.g., S1, etc.). Base stations 105 can communicate with each other via backhaul links 134 (e.g., X2, etc.) directly or indirectly (e.g., via the central network 130). Base stations 105 can perform radio configuration and programming for communication with UEs 115 or can operate under the control of a base station controller (not shown). In some examples, base stations 105 can be macro cells, small cells, hot spots, or similar. Base stations 105 can also be referred to as eNodeBs (eNBs) 105.

[0041] Time intervals in the LTE standard can be expressed in multiples of a basic unit of time (for example, the sampling period, Ts = 1 / 30,720,000 seconds). Time resources can be organized according to radio frames of length equal to 10 ms (Tf = 307200 Ts), which can be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame can include ten 1 ms subframes numbered from 0 to 9. A subframe can be further divided into two 0.5 ms slots, each containing 6 or 7 modulation symbol periods (depending on the length of the cyclic prefix (CP) added to each symbol). Excluding the CP, each symbol contains 2,048 sample periods.

[0042] In some cases, the subframe may be the smallest programming unit, also called a TTI. In other cases, a TTI may be shorter than a subframe or may be dynamically selected (e.g., in short bursts of TTIs or in component carriers (component carriers - CCs) using short TTIs). System 100 may support communications according to TTIs of different durations (e.g., 1 ms and 0.5 ms). In some cases, the duration of the TTI used for UL transmissions may be different from that used for DL ​​transmissions. For example, a slot TTI (0.5 ms) may be used for DL ​​transmissions and a subframe TTI (1 ms) may be used for UL transmissions. A 1 ms subframe may be referred to as an LTE subframe, LTE TTI, or legacy TTI.

[0043] Hybrid automatic repeat request (HARQ) can be a method of ensuring that data is correctly received over a 125 wireless communication link. HARQ can include a combination of error detection (e.g., using a CRC), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve transmission capability at the medium access control (MAC) layer in poor radio conditions (e.g., signal-to-noise conditions). In Incremental Redundancy HARQ, incorrectly received data can be stored in auxiliary memory and combined with subsequent transmissions to increase the overall probability of successful data decoding. In some cases, redundancy bits are added to each message before transmission. This can be useful in poor conditions.In other cases, no redundancy bits are added to each transmission, but they are retransmitted after the transmitter of the original message receives a negative acknowledgment (NACK) indicating a failed attempt to decode the information. The chain of transmission, response, and retransmission can be called a HARQ process. In some cases, a limited number of HARQ processes can be used for a given communication link. In some cases, HARQ synchronization may be distinct for low-latency and non-low-latency communications. In some cases, when using low-latency HARQ, the number of HARQ processes can be increased (for example, from a limit of 8 to 10 or more).

[0044] In some instances, the 100 wireless communications system may utilize enhanced component carriers (eCCs). An eCC may be characterized by one or more features, including: increased bandwidth, shorter symbol duration, shorter TTIs (e.g., 0.5 ms TTIs), or a modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation (CA) configuration or a dual connectivity configuration (e.g., when multiple operating cells have a lower or less-than-ideal backhaul link). An eCC may also be configured for use in unlicensed spectrum or shared spectrum (where more than one operator is permitted to use the spectrum).An eCC characterized by wide bandwidth may include one or more segments that can be used by UEs 115 that are unable to monitor the full bandwidth or that prefer to use a limited bandwidth (e.g., to conserve energy).

[0045] In some cases, one or more CCs, such as an eCC, in the 100 system may use a symbol duration distinct from other CCs, which may include the use of a reduced symbol duration compared to the symbol durations of other CCs. A shorter symbol duration may be associated with increased subcarrier spacing. A device, such as the UE 115 or base station 105, using eCCs may transmit broadband signals (e.g., 20, 40, 60, 80 MHz, etc.) in reduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC may consist of one or multiple symbols. In some cases, the TTI duration (i.e., the number of symbols in a TTI) may be variable.

[0046] A base station 105 can identify the UE's ability to provide HARQ for low-latency transmissions (e.g., TTIs of a shorter duration compared to other TTIs supported by the system 100). The base station can select a HARQ synchronization mode based on the capacity and indicate the selected HARQ synchronization mode to UE 115. The base station can then perform one or more low-latency data transmissions to UE 115, and the UE can respond with HARQ feedback based on the HARQ synchronization mode. In some cases, the HARQ synchronization mode may be based on different response times depending on the location of the data transmission. In other cases, the response times may be the same.

[0047] FIG. 2 illustrates an example of a 200 wireless communications system for HARQ synchronization for reduced TTIs. The 200 wireless communications system may include the base station105-a and the UE 115-a, which may be examples of the corresponding devices described with reference to FIG. 1. In some examples, the 200 wireless communications system may support various HARQ synchronization modes, including modes that provide a reduced RTT compared to legacy HARQ procedures.

[0048] In some systems, DL and UL transmissions may have different TTI durations (e.g., a duration of 0.5 ms for DL ​​and a duration of 1 ms for UL). For example, a physical uplink control channel (PUCCH) or a shared physical uplink control channel (PUSCH), or both, may be based on the longer UL TTI of 205 and may be used in conjunction with DL transmissions that utilize the shorter DL TTI of 210. In some cases, a single control channel (e.g., a physical downlink control channel (PDCCH)) may schedule multiple DL transmissions with reduced TTI durations (e.g., two slot-TTI transmissions during a subframe may be scheduled together). Alternatively, each reduced TTI transmission may be scheduled by a different control channel.

[0049] A shorter scheduled downlink TTI can enable reduced UL HARQ synchronization and then round-trip time (RTT) for retransmission of transport blocks (TBs). Furthermore, with a reduced TTI duration, TBs scheduled on different TTIs can have different UL HARQ synchronizations to facilitate common UL HARQ configurations for DL ​​transmissions with different TTIs.

[0050] In some examples, a HARQ synchronization mode can be selected to accommodate two distinct response DL transmissions occurring at different times. For example, a low-latency PDSCH transmission, such as a PDSCH using a low-latency TTI, can shorten a HARQ synchronization to a 2-slot gap or a 3-slot gap, which can provide a HARQ retransmission round-trip time (RTT) of 4 ms. In another example, the HARQ synchronization can be shortened to a 3-slot gap or a 4-slot gap, which can provide a HARQ RTT of 0.5 ms. In yet another example, the response time can be the same regardless of the transmission time, so that the control UL transmissions are temporally shifted (i.e., two control UL transmissions with the length of one subframe overlapping).In yet another example, HARQ synchronization for a DL slot can align with the synchronization of a 1 ms ACK / NACK transmission, but the low-latency HARQ RTT can be reduced to 6 ms. These examples illustrate configurations based on one-slot length TTIs and TTIs with a 1 ms subframe length. But other TTIs can also be employed to provide the low-latency advantages described here.

[0051] As described above, using a combination of 2-slot and 3-slot synchronization for HARQ responses can result in a retransmission RTT of 4 ms. For example, a TB transmitted in a first slot of a subframe (e.g., slot 0) might have 3-slot HARQ synchronization. A second slot (e.g., slot 1) might have 2-slot HARQ synchronization. In this example, the PUCCH features in each subframe for UL transmissions with 1 ms TTIs can be determined by a control channel four subframes earlier, whereas the PUCCH features for single-slot length TTIs can be determined by a control channel two subframes earlier.

[0052] In another example, using a combination of 3-slot and 4-slot synchronization can result in a HARQ RTT of 5 ms. In some examples using this configuration, DL synchronization may not align to a subframe boundary (although UL may align). That is, a first TB may be transmitted at the end of a subframe, and a second TB may be transmitted at the beginning of the next subframe. In such cases, a PUCCH in subframe n may carry HARQ to a second slot (e.g., slot 1) in subframe n - 3, and to the first slot (e.g., slot 0) in subframe n - 2. That is, a first slot (e.g., slot 1 of the first DL subframe) may have 4-slot HARQ synchronization. A second slot (e.g., slot 0 of the second DL subframe) may have 3-slot HARQ synchronization.

[0053] In some examples, DL TBs transmitted in distinct slots may have the same HARQ response synchronization, which may result in staggered PUCCH responses. For example, a 3-slot HARQ synchronization with staggered PUCCH may result in a HARQ RTT of 4 ms. In some cases, each slot-length TTI may be associated with a distinct 1 ms TTI PUCCH. If contiguous slot-TTI transmissions occur, the PUCCH for the two consecutive slot-TTI transmissions may result in parallel PUCCH transmissions (at least during a period of overlapping slot length) or modified PUCCH transmissions (e.g., transmissions that are multiplexed over a period of overlapping slot length).For example, for a slot 0 PDSCH in subframe n, the PUCCH can be transmitted in subframe n + 2; for the low-latency PDSCH transmitted in the second slot (i.e., slot 1) in the same subframe n, the PUCCH can be transmitted in slot 1 of subframe n + 2 and slot 0 in subframe n + 3.

[0054] In another example, using a combination of 7-slot and 8-slot response synchronizations can result in a retransmission RTT of 6 ms. In such cases, the PUCCH for slot-based DL transmissions can align with PUCCH transmissions of 1 ms-based DL transmissions that occur at the same time. However, the retransmission time for low-latency DL transmissions can be reduced relative to legacy operation (e.g., from 8 ms to 6 ms) by reducing the time period between the PUCCH and the subsequent retransmission.

[0055] Low-latency HARQ programming techniques, including those described herein, can reduce the possibility of PUCCH resource collisions. That is, collisions can result from using different HARQ response synchronizations for low-latency and non-low-latency DL transmissions together. For example, the possibility of a collision can arise from PUCCH transmission in subframe n, which corresponds to DL transmissions in subframe n - k1 for a 1 ms TTI, and DL transmissions in subframe n - k2 for a slot-length TTI. For example, k1 = 4, k2 = 2. Since k1 > k2 generally, the base station can avoid or minimize PUCCH resource collisions through appropriate slot-length TTI programming. For example, the initial offset of PUCCH resources can be configured separately for 1 ms length and 1 slot length.Base station 105-a can utilize two distinct offsets for the two TTIs, so that two distinct sets of PUCCH resources can be created.

[0056] Alternatively, for a 1-slot length TTI, another offset can be introduced on top of the offset configured for 1 ms. That is, if a first offset, Δ1, is for 1 ms, then a second offset, Δ1 + Δ2, can be used for 1 slot. The feature offset can depend on a PUCCH format – for example, a feature offset configured separately for each PUCCH format. For a given PUCCH format, two or more sets of features can also be used. The use of one or more sets of features can be programmed at the base station or configured by layer 3 (for example, applicable to distinct sets of subframes).

[0057] Thus, the use of 1 ms PUCCH for slot-TTI DL (e.g., a DL transmission using a reduced-duration TTI) can reduce HARQ synchronization and retransmission synchronization. In some cases, non-low latency HARQ (e.g., legacy HARQ) can be used for UEs 115 under unfavorable channel conditions, while low-latency HARQ can be used under more favorable conditions. However, when a UL control information is transmitting using a 1 ms TTI, a relatively larger synchronization advance can be used by UE 115-a (e.g., due to a relatively longer propagation delay), which can make it difficult to meet the HARQ deadline if the HARQ synchronization is shortened. That is, a HARQ synchronization for low-latency communications can be selected to accommodate parallel or concurrent HARQ operations within the system 200.

[0058] In this way, the 105-a base station can support more than one HARQ synchronization option, and the 115-a UE can have the ability to support one or more of these synchronization options. For example, the 115-a UE can support a HARQ synchronization mode that provides low-latency DL transmissions if, for example, the 115-a UE has advanced processing power compared to other 115 UEs. Another 115 UE can support a different synchronization mode if it has processing power constraints (for example, a machine-type communication device - MTC). In some cases, a 105-a base station can indicate a HARQ synchronization option to a 115-a UE and the 115-a UE can request a desired HARQ synchronization.

[0059] The use of a 1 ms duration PUCCH (instead of a low-latency PUCCH) for HARQ feedback for DL ​​transmission using a 1-slot duration TTI may also be tied to how the 1-slot duration TTI is programmed. For example, if DL transmission on a 1-slot duration TTI is programmed by granting multiple TTIs, a 1 ms duration PUCCH can be used to provide HARQ feedback. Otherwise, a 1-slot duration TTI PUCCH can be used. However, in some cases, the 200 system may operate more efficiently if a 1 ms duration PUCCH is used in several or most scenarios.

[0060] In some examples, a downlink assignment index (DAI) can also be used to indicate how many 1-slot duration TTI transmissions are scheduled for feedback in a PUCCH (e.g., slot 0 only, slot 1 only, or both slots within a carrier and traversing carriers). The DAI can count, cumulatively or in total, the number of scheduled DL transmissions. Additionally or alternatively, HARQ feedback can be sent using 1 ms duration PUCCHs with synchronization similar to that described here for feedback provided in a 1 ms duration PUCCH.

[0061] In some cases, low-latency HARQ synchronization may include UL scheduling or HARQ synchronization for joint leases. If joint lease operation is supported, UL scheduling / HARQ synchronization may be based on slot 0 synchronization. For example, a control channel may be legacy PDCCH or shortened EPDCCH (i.e., EPDCCH slot 0 only), where scheduling may occur in both slot 0 and slot 1. In other words, if a 1 ms duration PUCCH is used for HARQ feedback, the control channel scheduling a 1-slot duration TTI PUCCH transmission may be present in slot 0. In such cases, for low-latency slot 1 PUCCH transmission, there may be 1 ms for the base station to process and determine whether or not retransmissions should be performed (a degree of relaxation is possible, as in DL, but not necessary).

[0062] In some examples, within a UL subframe, scheduling determinations for a low-latency PUSCH and a 1 ms TTI PUSCH can be made in separate subframes. For example, for a 1 ms TTI, scheduling determination can be made at 4 ms or earlier; and for a 1-slot TTI, scheduling decision can be made at 2 ms or earlier. Such scheduling can be located at a system operator or at base station 105-a to avoid resource fragmentation. Alternatively, a 2 ms schedule can also be used for a 1 ms PUSCH.

[0063] In some cases, a HARQ synchronization mode or advance HARQ synchronization can be selected to accommodate dynamic and semi-persistent scheduling (SPS) traffic. If dynamic scheduling and SPS (from the same TTI) occur in the same subframe, dynamic scheduling may take precedence. If different TTIs are supported, dynamic scheduling from a first TTI may collide with SPS scheduling from a second TTI in the same subframe. For example, there may be dynamic scheduling of 1 ms duration and SPS of 1 slot duration. In such cases, the SPS with TTI of 1 slot duration may be interrupted (e.g., for receive or transmit), while the 1 ms one may take precedence. In some examples, there may be dynamic scheduling of 1 slot and SPS of 1 ms for a DL transmission.In such cases, if the dynamic control channel with a TTI duration of 1 slot (for example, programming data transmissions from slot 0 or data transmissions from both slot 0 and slot 1) is received in slot 0, the 1 ms-based SPS may be interrupted.

[0064] In some examples, if the dynamic control channel with a 1-slot TTI duration is received in slot 1, the UE may buffer the potential SPS traffic for the entire subframe in order to determine whether or not to monitor the SPS (for example, the base station may still transmit SPS in slot 0, but the UE may not be required to decode it). Alternatively, a 1 ms SPS duration may be given higher priority than a control channel with a 1-slot TTI duration in slot 1. That is, if a subframe has a 1 ms SPS duration for a UL transmission, the data transmission of the slot 1 programming channel may not be performed in slot 1. In another example, there may be a 1-slot dynamic and a 1 ms SPS duration for a UL transmission or during a UL TTI. In such cases, the 1 ms SPS duration may be interrupted.In general, the SPS of a second TTI can be interrupted due to the dynamic scheduling of a first TTI in the same subframe.

[0065] Further examples of uplink and downlink channel operations and configurations for low-latency HARQ feedback synchronization are described below. FIG. 3 illustrates an example of a 300-channel configuration for HARQ synchronization for reduced TTIs. In some cases, the 300-channel configuration may represent aspects of techniques performed by a UE 115 or base station105 as described in reference to FIGS. 1-2. The 300-channel configuration may represent an example based on 2-slot and 3-slot duration HARQ synchronization as described in reference to FIGS. 1 and 2.

[0066] Low-latency DL 302 transmissions can be performed over DL carrier 310. For example, low-latency DL 302 transmissions can be performed during slot 0 305-a and slot 1 305-b of DL carrier 310 during subframe 325. UL 315 control transmission (i.e., a PUCCH transmission with a 1 ms TTI duration corresponding to low-latency DL 302 transmissions) can be performed over UL carrier 320 in subframe 327. Low-latency DL 304 retransmissions can then be performed over DL carrier 310 in slot 0 306-a and slot 1 306-b of subframe 328, which may be four subframes after subframe 325 (i.e., an RTT). (retransmission duration of 4 ms).

[0067] Non-low latency DL transmission 329 can be performed via carrier 310 in two consecutive slots (e.g., slot 0 305-a and slot 1 305-b) during subframe 325. Non-low latency UL control transmission 330 can be performed via carrier 320 in subframe 331 and non-low latency DL retransmission 333 can be sent in subframe 335, which can be eight subframes after subframe 325 (i.e., an 8 ms duration retransmission RTT).

[0068] FIG. 4 illustrates an example of a 400 carrier configuration for HARQ synchronization for reduced TTIs. In some cases, the 400 carrier configuration may represent aspects of techniques performed by a UE 115 or base station 105 as described in reference to FIGS. 1 - 2. The 400 configuration may represent an example based on 3-slot and 4-slot duration HARQ response synchronization as described in reference to FIGS. 1 and 2.

[0069] Low latency DL 402 transmissions can be performed via DL 410 carrier. For example, low latency DL 402 transmission can be performed during slot 0 405-b of DL 410 carrier during subframe 425 and slot 1 405-a of a previous subframe 427. Low-latency UL control transmission 415 (i.e., PUCCH transmission corresponding to low-latency DL transmissions 402) can be performed via UL carrier 420 in subframe 428. Low-latency DL retransmissions 404-b can then be performed via DL carrier 410 during slot 0 406-a and slot 1 406-b of subframe 429, which can be five subframes after subframe 425 (i.e., a 5 ms duration RTT).

[0070] Non-low latency DL transmission 430 can be performed via DL carrier 410 in two consecutive slots of subframe 425. Non-low latency UL control transmission 431 can be performed on UL carrier 420 in subframe 433 and non-low latency DL retransmission 434 can be sent in subframe 435, which can be eight subframes after subframe 425 (i.e., an RTT duration of 8 ms).

[0071] FIG. 5 illustrates an example of a 500 carrier configuration for HARQ synchronization for reduced TTIs. In some cases, the 500 carrier configuration may represent aspects of techniques performed by a UE 115 or base station 105 as described in reference to FIGS. 1 - 2. The 500 configuration may represent an example based on HARQ response synchronization as described in reference to FIGS. 1 and 2.

[0072] Low-latency DL transmissions 502 can be performed over DL carrier 510. For example, low-latency DL transmission 502 can be performed during slot 0 505-a and slot 1 505-b of DL carrier 510 during 525. Low-latency UL control transmission 515-a (i.e., PUCCH transmission corresponding to low-latency DL transmission 502 during slot 505-a) and low-latency UL control transmission 515-b (i.e., PUCCH transmission corresponding to low-latency DL transmission 502 during slot 1 505-b) can be performed over UL carrier 520 in time slots 517 and 518, each lasting one subframe starting three slots after slot 0 505-a and slot 1 505-b. 505-b, respectively.Low-latency DL retransmissions 504 can then be performed via DL carrier 510 during slot 0 506-a and slot 1 506-b of subframe 527, which may be four subframes after subframe 525 (i.e., a 4 ms duration RTT).

[0073] Non-low latency DL transmission 530 can be performed via DL carrier 510 in two consecutive slots during 525. Non-low latency UL control transmission 520 can be performed via UL carrier 532 in subframe 532 and non-low latency DL retransmission 533 can be sent in subframe 535, which can be eight subframes after subframe 525 (i.e., an RTT duration of 8 ms).

[0074] FIG. 6 illustrates an example of slot 600 configurations for HARQ synchronization for reduced TTIs. The slot 600 configurations may represent aspects of transmissions performed by a UE 115 as described in reference to FIG. 5, and more specifically in reference to examples of feedback transmitted during periods 517 and 518 of FIG. 5.

[0075] In configuration 600-a, two distinct PUCCH transmissions 610 and 615 with control information transmissions (e.g., ACK / NACK for distinct low-latency DL) can occupy the same slot of time periods 517-a and 518-a. In some examples, the two PUCCH transmissions 610 and 615 can be mapped to the same RB, which can improve operating constraints (e.g., such mapping can serve to limit maximum power reduction (NIPR) requirements for modulation).

[0076] In the 600-b configuration, a modified PUCCH 625 can be used to carry HARQ responses for multiple low-latency DL transmissions. For example, 2-bit HARQ feedback can be used for each 1-slot duration DL transmission for which feedback is sent. As an example, the 3 slots in time periods 517-a and 518-a can provide 2-bit, 4-bit, and 2-bit HARQ feedback, respectively. For example, PUCCH format 3 can be used, which can have a payload of 2 bits, 4 bits, and 2 bits, respectively, for the three slots. Alternatively, PUCCH format 1b can be used with a modified format operation, and the second slot can carry 4 bits. For example, there can be four data symbols in a slot, which can carry the same QPSK symbol (2 bits). Data symbols can include two pairs of symbols, each containing a distinct QPSK symbol, thus creating a 4-bit payload in a slot.Thus, for a propagation length of four, for UEs 115 capable of such a reduced duration, HARQ synchronization can use propagation codes [+1, +1, +1, +1] or [+1, +1, —1, —1], and the legacy PUCCH can still be multiplexed in the same resource block (RB) if the UEs 115 transmitting the legacy PUCCH use propagation codes [+1, —1, +1, —1] or [+1, —1, —1, +1], for example.

[0077] The 600-b configuration can additionally or alternatively support other aspects of HARQ synchronization for reduced TTIs. For example, if a UE 115 is configured to use a modified uplink format and does not detect a grant for the second slot of a DL transmission (e.g., fault detection), the base station may not know whether the grant was received or not. Then, in some cases, the 600-b configuration can allow the second pair (i.e., the last two single-carrier frequency division multiplexing (SC-FDM) symbols) of the second slot (i.e., the overlapping slot of time periods 517-ae and 518-a) to be empty. In such cases, orthogonality can still be maintained.

[0078] Alternatively, the second slot of the 600-b configuration can be arranged so that the first two symbols can carry the first two bits, b0 and b1, and the second two symbols can carry bits b2 and b3, however, an XOR operation of the first and second bits respectively can be used, i.e., b0 XOR b2 and b1 XOR b3 can be used to indicate whether a grant in the second slot has been received. For example, when the second slot is not programmed by the base station, the base station can determine that b2 = NAK and b3 = NAK, so that b0 and b1 can be repeated. The performance loss may be minimal in this example, compared to alternative ways of transmitting similar information. When the second slot is programmed by the base station, the bits can be decoded together and there may be some performance loss due to error propagation (i.e., an error in one bit creates errors in two bits).

[0079] The 600-b configuration may also depend on, for example, an employed orthogonal cover code (OCC). For example, if the OCC is of length three of the discrete Fourier transform (discrete Fourier transform - DFT) (e.g., OCC [1, 1, 1] for legacy PUCCH; other OCC codes may be [1, (j π / 3) (j π / 3) 1 (j π / 3) (j π / 3) D t 3e 2 , e 4 ] or [1, e 4 , e 2 ]). Among the 3 symbols in a PUCCH slot (s0, s1, s2), s0 can carry ACK / NAK for the first DL transmission with 1-slot TTI, s2 can carry ACK / NAK for the second DL transmission with 1-slot TTI, and s2 can be a "parity," such that s2 = -(s0 + s1). In such cases, orthogonality can be maintained with legacy operations since s0 + s1 + s2 = 0. If the three received symbols are r0, r1, and r2, then the original symbols can be recovered since s0 = [-(2r0 - r1 - r2)] / 3 and s1 = [(2r1 - r0 - r2)] / 3. Similarly, the HARQ synchronization described with reference to FIGS.5 and 6 can establish various options for transmitting HARQ feedback for low-latency transmissions while maintaining compatibility with legacy operation.

[0080] FIG. 7 illustrates an example of a 700 carrier configuration for HARQ synchronization for reduced TTIs. In some cases, the 700 carrier configuration may represent aspects of techniques performed by a UE 115 or base station 105 as described in reference to FIGS. 1 - 2. The 700 configuration may represent an example based on 6-slot duration HARQ response synchronization as described in reference to FIGS. 1 - 2.

[0081] Low-latency DL transmissions 702 can be performed via DL carrier 710. For example, low-latency DL transmission 702 can be programmed during slot 0 705-a and slot 1 705-b of DL carrier 710 during subframe 725. Low-latency UL control transmission 715 (i.e., PUCCH transmission corresponding to low-latency DL transmissions 702) can be performed via UL carrier 720 in subframe 730. Low-latency DL retransmissions 704 can then be performed via carrier 710 during slot 0 706-a and slot 1 706-b of subframe 731, which can be six subframes after subframe 725 (i.e., a 6 ms RTT duration).

[0082] Non-low latency DL transmissions 732 can be performed via DL carrier 710 in two consecutive slots during subframe 725. Non-low latency UL control transmissions 733 can be performed on UL carrier 720 also in subframe 730, and non-low latency DL retransmission 734 can be sent in subframe 735, which can be eight subframes after subframe 725 (i.e., an RTT duration of 8 ms).

[0083] FIG. 8 illustrates an example of process flow 800 for synchronization of HARQ to reduced TTIs in accordance with various aspects of this disclosure. Process flow 800 may include base station 105-aeo UE 115-a, which may be examples of the corresponding devices described with reference to FIGS. 1 - 2.

[0084] In step 805, base station 105-a can receive an indication of the HARQ feedback capability of UE 115-a. In step 810, base station 105-a can identify a UE 115 capability to provide HARQ feedback associated with TTIs of a second duration. In step 815, base station 105-a can select a HARQ synchronization mode based at least in part on the UE 115-a capability. In step 820, base station 105 can transmit an indication of the HARQ synchronization mode to UE 115-a.

[0085] In step 825, base station 105-a can transmit a first transport block (TB) during a first transmission time interval (TTI) and a second TB during a second TTI of a second duration. Furthermore, the first TB can be associated with an uplink (UL) resource for HARQ feedback, which can be based at least in part on a downlink (DL) control channel transmitted during a time period four times the second duration prior to the transmission of the first TB.

[0086] In step 830, base station 105-a can <t1 / identificar um período de tempo de realimentação baseado ao menos em parte na modalidade de sincronização de HARQ. Além disso, a modalidade de sincronização de HARQ pode incluir um primeiro tempo de resposta de HARQ de quatro vezes a segunda duração e um segundo tempo de resposta de HARQ de três vezes a segunda duração.

[0087] In step 835, base station 105-a may receive one or more HARQ feedback messages associated with the first and second TBs, wherein such HARQ feedback message(s) are received during a first duration TTI. Furthermore, such HARQ feedback message(s) may comprise a first HARQ feedback message and a second HARQ feedback message, wherein the first HARQ feedback message is associated with the first TB and the second HARQ feedback message is associated with the second TB. Additionally, the first and second HARQ feedback messages may be configured according to the first duration.

[0088] In step 840, base station 105-a can retransmit the first TB or the second TB based at least in part on a retransmission time of ten times the second duration.

[0089] FIG. 9 shows a block diagram of a wireless device 900 supporting HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The wireless device 900 may be an example of aspects of a UE 115 or base station 105 described with reference to FIGS. 1 and 2. The wireless device 900 may include the receiver 905, the HARQ synchronization manager 910, and the transmitter 915. The wireless device 900 may also include a processor. Each of these components may be in communication with the others.

[0090] Receiver 905 can receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information relating to HARQ synchronization for reduced TTIs, etc.). The information can be relayed to other components of the device. Receiver 905 can be an example of aspects of transceiver 1225 described with reference to FIG. 12.

[0091] The HARQ synchronization manager 910 can determine the HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs and to communicate, in combination with the receiver 905 or the transmitter 915, or both, using the HARQ synchronization mode. The HARQ synchronization manager 910 can also be an example of aspects of the HARQ synchronization manager 1205 described with reference to FIG. 12.

[0092] The transmitter 915 can transmit signals received from other components of the wireless device 900. In some examples, the transmitter 915 can be juxtaposed with a receiver in a transceiver module. For example, the transmitter 915 can be an example of aspects of the transceiver1225 described in reference to FIG. 12. The transmitter 915 can include a single antenna or a plurality of antennas.

[0093] FIG. 10 shows a block diagram of a wireless device 1000 supporting HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The wireless device 1000 may be an example of aspects of a wireless device 900 or a UE 115 or base station 105 described in reference to FIGS. 1, 2 and 9. The wireless device 1000 may include the receiver 1005, the HARQ synchronization manager 1010 and the transmitter 1025. The wireless device 1000 may also include a processor. Each of these components may be in communication with the others.

[0094] Receiver 1005 can receive information that can be relayed to other components of the device. Receiver 1005 can also perform the functions described with reference to receiver 905 in FIG. 9. Receiver 1005 can be an example of aspects of transceiver 1225 described with reference to FIG. 12.

[0095] The HARQ 1010 synchronization manager may be an example of aspects of the HARQ 910 synchronization manager described in reference to FIG. 9. The HARQ 1010 synchronization manager may include the HARQ 1015 synchronization mode component and the 1020 low-latency communication component. The HARQ 1010 synchronization manager may be an example of aspects of the HARQ 1205 synchronization manager described in reference to FIG. 12.

[0096] The HARQ 1015 synchronization mode component can transmit to a base station an indication of one or more UE capabilities, receive from a base station an indication of a set of HARQ synchronization modes, and determine a HARQ synchronization mode based on one or more UE capabilities to provide HARQ feedback in response to communications using second-duration TTIs. The operations of the HARQ 1015 synchronization mode component can be performed in combination with the 1005 receiver or the 1025 transmitter in several instances.

[0097] The low-latency communication component 1020 can communicate, in combination with the receiver 1005 or the transmitter 1025, using the HARQ synchronization mode. In some cases, the communication includes receiving a first TB during a first TTI and a second TB during a second TTI, where the first TTU and the second TTI each have the second duration. In some cases, the first TTI is located within a final part of a first time period that has the first duration, and the second TTI is located in an initial part of a second time period that has the first duration. In some cases, the communication includes transmitting a first TB during a first TTI and a second TB during a second TTI, where the first TTU and the second TTI each have the second duration.

[0098] The 1025 transmitter can transmit signals received from other components of the 1000 wireless device. In some examples, the 1025 transmitter can be juxtaposed with a receiver in a transceiver module. For example, the 1025 transmitter can be an example of aspects of the 1225 transceiver described in reference to FIG. 12. The 1025 transmitter can use a single antenna or a plurality of antennas.

[0099] FIG. 11 shows a block diagram of a HARQ 1100 synchronization manager which may be an example of the corresponding component of the 900 wireless device or the 1000 wireless device. That is, the HARQ 1100 synchronization manager may be an example of aspects of the HARQ 910 synchronization manager or the HARQ 1010 synchronization manager described in reference to FIGS 9 and 10. The HARQ 1100 synchronization manager may also be an example of aspects of the HARQ 1205 synchronization manager described in reference to FIG. 12.

[00100] The HARQ synchronization manager may include the feedback time period component 1105, the HARQ feedback component 1110, the HARQ synchronization mode component 1115, the HARQ synchronization mode request component 1120, the UL control configuration component 1125, the PUCCH feature shift component 1130, the DL transmission indicator component 1135, and the low-latency communication component 1140. Each of these modules may communicate with the others, either directly or indirectly (e.g., via one or more buses).

[00101] The feedback time period component 1105 can identify a feedback time period based on the HARQ synchronization mode, wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time, or wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is less than the first HARQ response time.

[00102] The HARQ feedback component 1110 can transmit or receive one or more HARQ feedback messages associated with the first or second TB during the feedback time period, wherein one or more HARQ feedback messages are received during a TTI of the first duration. The HARQ feedback component 1110 can perform operations in conjunction with a receiver 1005 or a transmitter 1025 of FIG. 10. In some cases, one or more HARQ feedback messages include a first HARQ feedback message and a second HARQ feedback message distinct from the first HARQ feedback message.In some cases, a final portion of the first HARQ feedback message and an initial portion of the second HARQ feedback message are multiplexed using at least one of the following: a PUCCH format capable of carrying more than two bits, a bit split between the final portion of the first HARQ feedback message and the initial portion of the second HARQ feedback message, joint encoding of one or more bits of the first HARQ feedback message and the second HARQ feedback message, a bit combination based on an orthogonal cover code (OCC) and at least one parity bit, or any combination thereof.

[00103] The HARQ 1115 synchronization mode component can transmit an indication of one or more UE capabilities to a base station, receive from a base station an indication of a set of HARQ synchronization modes, and determine a HARQ synchronization mode based on one or more UE capabilities to provide HARQ feedback in response to communications using second-duration TTIs. The operations of the HARQ 1115 synchronization mode component can be performed in combination with receiver 1005 or transmitter 1025 of FIG. 10.

[00104] In combination with transmitter 1025, HARQ synchronization mode request component 1120 can transmit a HARQ synchronization mode request in response to the indication, wherein the HARQ synchronization mode is selected from the set of HARQ synchronization modes based on the requested HARQ synchronization mode. UL control configuration component 1125 can identify a UL control configuration based on the HARQ synchronization mode and transmit a UL control configuration indication to a UE.

[00105] The PUCCH 1130 resource offset component can identify a first PUCCH resource offset for UL transmissions using first-duration TTISs and a second PUCCH resource offset for UL transmissions using second-duration TTISs. In some cases, the second PUCCH resource offset is identified based on the first PUCCH resource offset and a delta value. In some cases, the first PUCCH resource offset or the second PUCCH resource offset is identified based on a PUCCH format. In some cases, one or more of the resource sets for UL transmissions are associated with each PUCCH format or a set of PUCCH formats, and wherein one or more of the resource sets are each associated with a different base station or layer three preconfiguration.

[00106] The DL 1135 transmission indicator component can identify a first programmed DL transmission indicator component, associated with first-duration TTIs, and a second programmed DL transmission indicator, associated with second-duration TTIs.

[00107] The low-latency communication component 1140 can communicate using the HARQ synchronization mode. In some cases, the communication includes the transmission or reception of a first TB during a first TTI and a second TB during a second TTI, where the first TTI and the second TTI each have the second duration. Operations of the low-latency communication component 1140 can be performed in combination with a receiver 1005 or a transmitter 1025 of FIG. 10.

[00108] FIG. 12 shows a diagram of a 1200 system that includes a device supporting HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. For example, the 1200 system may include a UE 115-c, which may be an example of a 900 wireless device, a 1000 wireless device, or a UE 115 as described in reference to FIGS. 1, 2, and 9 through 11.

[00109] The UE 115-c may also include a HARQ synchronization manager 1205, memory 1210, a transceiver 1225, an antenna 1230, and an ECC module 1235. Each of these modules may communicate with the others, either directly or indirectly (e.g., via one or more buses). The HARQ synchronization manager 1205 may be an example of a primary module as described in reference to FIGS. 9 through 11.

[00110] Memory 1210 may include random access memory (RAM) and read-only memory (ROM). Memory 1210 may store computer-readable and executable software, including instructions that, when executed, cause the processor to perform various functions described herein (e.g., synchronization of HARQs for reduced TTIs, etc.). In some cases, software 1215 may not be directly executable by the processor, but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor 1220 may include an intelligent hardware device (e.g., a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc.).

[00111] The 1225 transceiver can communicate bidirectionally, through one or more antennas, wired or wireless links, with one or more networks, as described above. For example, the 1225 transceiver can communicate bidirectionally with a 105 base station or a 115 UE. The 1225 transceiver may also include a modem to modulate packets and provide modulated packets to antennas for transmission and to demodulate packets received from antennas. In some cases, the wireless device may include a single 1230 antenna. However, in some cases, the device may have more than one 1230 antenna, which may have the capability to transmit or receive multiple wireless transmissions simultaneously.

[00112] The ECC 1335 module can enable operations using enhanced component carriers (ECCs) such as communication using shared or unlicensed spectrum, using reduced TTIs or reduced subframe durations, or using a large number of component carriers.

[00113] FIG. 13 shows a diagram of a 1300 wireless system including a configured device that supports HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. For example, the 1300 system may include the 105-d base station, which may be an example of a 900 wireless device, a 1000 wireless device, or a 105 base station as described in reference to FIGS. 1, 2 and 9 through 11. The 105-d base station may also include components for bidirectional voice and data communication, as well as components for transmitting communications and components for receiving communications. For example, 105-d base stations may communicate bidirectionally with one or more of the 115 UEs.

[00114] The base station 105-d may also include the primary module 1305, the memory 1310, the processor 1320, the transceiver 1325, the antenna 1330, the base station communications module 1335, and the network communications module 1340. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses). The primary module 1305 may be an example of a primary module as described in reference to FIGS. 9 to 11.

[00115] 1310 memory may include RAM and ROM. 1310 memory may store computer-readable and executable software, including instructions that, when executed, cause the processor to perform various functions described herein (e.g., synchronization of HARQs for reduced TTIs, etc.). In some cases, 1315 software may not be directly executable by the processor, but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The 1320 processor may include an intelligent hardware device (e.g., a CPU, a microcontroller, an ASIC, etc.).

[00116] The 1325 transceiver can communicate bidirectionally, through one or more antennas, wired or wireless links, with one or more networks, as described above. For example, the 1325 transceiver can communicate bidirectionally with a 105 base station or a 115 UE. The 1325 transceiver may also include a modem to modulate packets and provide modulated packets to antennas for transmission and to demodulate packets received from antennas. In some cases, the wireless device may include a single 1330 antenna. However, in some cases, the device may have more than one 1230 antenna, which may have the capability to transmit or receive multiple wireless transmissions simultaneously.

[00117] The 1335 base station communications module can manage communications with other 105 base stations, and may include a controller or programmer to control communication with 115 UEs in cooperation with other 105 base stations. For example, the 1335 base station communications module can coordinate programming for transmissions to 115 UEs for various interference attenuation techniques, such as spatial filtering or joint transmission. In some examples, the 1335 base station communications module can provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communication between 105 base stations.

[00118] The 1340 network communication module can manage communications with the central network (e.g., via one or more wired backhaul links). For example, the 1340 network communication module can manage the transfer of communication data to client devices, such as one or more 115 UEs.

[00119] FIG. 14 shows a flow diagram illustrating a 1400 method for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of the 1400 method can be implemented by a device such as a UE 115 or base station 105 or their components as described in reference to FIGS. 1 and 2. For example, the operations of the 1400 method can be performed by the HARQ synchronization manager as described herein. In some examples, the UE 115 or base station 105 can execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE 115 or base station 105 can perform aspects of the functions described below using special-purpose hardware.

[00120] In block 1405, UE 115 or base station 105 operating in a system that supports communications using first-duration and second-duration TTIs may determine a HARQ synchronization mode based on one or more UE capabilities to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain instances, block 1405 operations may be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00121] In block 1410, UE 115 or base station 105 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In certain examples, block 1410 operations can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by transceivers 1225 or 1325 as described with reference to FIGS. 12 and 13.

[00122] FIG. 15 shows a flow diagram illustrating a 1500 method for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of the 1500 method can be implemented by a device such as a UE 115 or its components as described in reference to FIGS. 1 and 2. For example, the operations of the 1500 method can be performed by the HARQ synchronization manager as described herein. In some examples, the UE 115 can execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE 115 can perform aspects of the functions described below using purpose-built hardware.

[00123] In block 1505, UE 115 operating in a system that supports communications using first-duration and second-duration TTIs may determine a HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain instances, block 1505 operations may be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00124] In block 1510, UE 115 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In some cases, the communication includes receiving a first TB during a first TTI and a second TB during a second TTI, where the first TTI and the second TTI each have the second duration. In certain examples, the operations of block 1510 can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by transceiver 1225 as described with reference to FIG. 12.

[00125] In block 1515, UE 115 can identify a feedback time period based on the HARQ synchronization mode, wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1515 can be performed by the feedback time period component as described with reference to FIGS. 10 and 11.

[00126] In block 1520, UE 115 may transmit one or more HARQ feedback messages associated with the first or second TBs during the feedback time period, wherein such HARQ feedback message or messages are received during a first duration TTI as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1520 may be performed by the HARQ feedback component as described with reference to FIGS. 10 and 11 or by transceiver 1225 as described with reference to FIGS. 12.

[00127] FIG. 16 shows a flow diagram illustrating a method1600 for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of method 1600 can be implemented by a device such as a UE 115 or its components as described in reference to FIGS. 1 and 2. For example, the operations of method 1600 can be performed by the HARQ synchronization manager as described herein. In some examples, the UE 115 can execute a set of code to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE 115 can perform aspects of the functions described below using purpose-built hardware.

[00128] In block 1605, UE 115 operating in a system that supports communications using first-duration and second-duration TTIs can determine a HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain examples, block 1605 operations can be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00129] In block 1610, UE 115 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In some cases, the communication includes receiving a first TB during a first TTI and a second TB during a second TTI, where the first TTI and the second TTI each have the second duration. In certain examples, the operations of block 1610 can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by the 1225 transceivers as described with reference to FIG. 12.

[00130] In block 1615, UE 115 can identify a feedback time period based on the HARQ synchronization mode, wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1615 can be performed by the HARQ feedback component as described with reference to FIGS. 10 and 11.

[00131] In block 1620, UE 115 may transmit one or more HARQ feedback messages associated with the first or second TBs during the feedback time period, wherein such HARQ feedback message or messages are received during a first duration TTI as described above with reference to FIGS. 2 to 8. In certain instances, the block 1620 operations may be performed by the HARQ feedback component as described with reference to FIGS. 10 and 11 or by transceiver 1225 as described with reference to FIGS. 12.

[00132] FIG. 17 shows a flow diagram illustrating a method1700 for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of method 1700 can be implemented by a device such as a UE 115 or its components as described in reference to FIGS. 1 and 2. For example, the operations of method 1700 can be performed by the HARQ synchronization manager as described herein. In some examples, the UE 115 can execute a set of code to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE 115 can perform aspects of the functions described below using purpose-built hardware.

[00133] In block 1705, UE 115 operating in a system that supports communications using first-duration and second-duration TTIs can transmit to a base station an indication of one or more UE capabilities as described above with reference to FIGS. 2 to 8. In certain instances, block 1705 operations can be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00134] In block 1710, UE 115 can determine a HARQ synchronization mode based on one or more capabilities of a UE to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain instances, block 1710 operations can be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00135] In block 1715, UE 115 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In certain examples, block 1715 operations can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by transceiver 1225 as described with reference to FIG. 12.

[00136] FIG. 18 shows a flow diagram illustrating a method1800 for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of method 1800 can be implemented by a device such as a base station 105 or its components as described in reference to FIGS. 1 and 2. For example, the operations of method 1800 can be performed by the HARQ synchronization manager as described herein. In some examples, the base station 105 can execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station 105 can perform aspects of the functions described below using purpose-built hardware.

[00137] In block 1805, base station 105 operating in a system that supports communications using first-duration and second-duration TTIs may determine a HARQ synchronization mode based on one or more UE capabilities to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain instances, block 1805 operations may be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00138] In block 1810, base station 105 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In some cases, the communication includes the transmission of a first TB during a first TTI and a second TB during a second TTI, where the first TTI and the second TTI each have the second duration. In certain examples, the operations of block 1810 can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by transceiver 1325 as described with reference to FIG. 13.

[00139] In block 1815, base station 105 can identify a feedback time period based on the HARQ synchronization mode, wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1815 can be performed by the feedback time period component as described with reference to FIGS. 10 and 11.

[00140] In block 1820, base station 105 may receive one or more HARQ feedback messages associated with the first or second TBs during the feedback time period, wherein such HARQ feedback message or messages are received during a first duration TTI as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1820 may be performed by the HARQ feedback component as described with reference to FIGS. 10 and 11 or by transceiver 1325 as described with reference to FIGS. 13.

[00141] FIG. 15 shows a flow diagram illustrating a 1900 method for HARQ synchronization for reduced TTIs in accordance with various aspects of this disclosure. The operations of the 1900 method can be implemented by a device such as a 105 base station or its components as described in reference to FIGS. 1 and 2. For example, the operations of the 1900 method can be performed by the HARQ synchronization manager as described herein. In some examples, the 105 base station may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the 105 base station may perform aspects of the functions described below using purpose-built hardware.

[00142] In block 1905, base station 105 operating in a system that supports communications using first-duration and second-duration TTIs may determine a HARQ synchronization mode based on one or more UE capabilities to provide HARQ feedback in response to communications using second-duration TTIs as described above with reference to FIGS. 2 to 8. In certain instances, block 1905 operations may be performed by the HARQ synchronization mode component as described with reference to FIGS. 10 and 11.

[00143] In block 1910, base station 105 can communicate using the HARQ synchronization mode as described above with reference to FIGS. 2 to 8. In some cases, the communication includes the transmission of a first TB during a first TTI and a second TB during a second TTI, where the first TTI and the second TTI each have the second duration. In certain examples, the operations of block 1910 can be performed by the low-latency communication component as described with reference to FIGS. 10 and 11 or by transceiver 1325 as described with reference to FIG. 13.

[00144] In block 1915, base station 105 can identify a feedback time period based on the HARQ synchronization mode, wherein the HARQ synchronization mode includes a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1915 can be performed by the feedback time period component as described with reference to FIGS. 10 and 11.

[00145] In block 1920, base station 105 may receive one or more HARQ feedback messages associated with the first or second TBs during the feedback time period, wherein such HARQ feedback message or messages are received during a TTI of the first duration as described above with reference to FIGS. 2 to 8. In certain instances, the operations of block 1920 may be performed by the HARQ feedback component as described with reference to FIGS. 10 and 11 or by transceiver 1325 as described with reference to FIGS. 13.

[00146] It should be noted that these methods and processes describe possible implementations, and that operations and steps can be rearranged or modified so that other implementations are possible. In some examples, aspects of two or more of the methods can be combined. For example, aspects of each of the methods may include steps or aspects of the other methods, or other steps or techniques described herein. Thus, aspects of the disclosure can establish HARQ synchronization for reduced TTIs.

[00147] The description given here is intended to enable someone with technical expertise to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those with technical expertise, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure should not be understood as limited to the examples and designs described herein, but rather to be given the broader scope consistent with the innovative principles and features described herein.

[00148] The functions described herein may be implemented in hardware, processor-executed software, firmware, or any combination thereof. If implemented in processor-executed software, the functions may be stored in a computer-readable medium in the form of one or more instructions or code, or transmitted in such form via such medium. Other examples and implementations are within the scope of the appended disclosure and claims. For example, due to the nature of software, the functions described above may be implemented using processor-executed software, hardware, firmware, wired devices, or combinations thereof. Resources implementing functions may also be physically located in multiple locations, including distributed in such a way that portions of the functions are implemented in distinct physical locations.Furthermore, for the purposes of this document, including the claims, the term "or" used in a list of items (for example, a list of items preceded by a phrase such as "at least one of" or "one or more") indicates an inclusive list, so 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).

[00149] The term "computer-readable media" includes both non-transient computer storage media and communication media, including any media that facilitates the transfer of a computer program. <t0 / >From one location to another. A non-transient storage medium can be any available media that can be accessed through a general-purpose or special-purpose computer. By way of example, and not for limitation, computer-readable non-transient media may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disk read-only memory (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other non-transient media that can be used to transport or store the desired program codes in the form of instructions or data structures and that can be accessed through a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.Furthermore, it is permissible to refer to any connection as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the definition of media includes the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves. As used herein, the term "disk" encompasses CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, both in terms of discs that reproduce data magnetically and discs that reproduce data optically with a laser. Combinations of the above items are also included within the scope of computer-readable media.

[00150] The techniques described here can be used for various wireless communication systems, such as CDMA, TDMA, FDMA, OFDMA, single carrier frequency division multiple access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 encompasses the IS-2000, IS-95, and IS856 standards. Versions 0 and A of the IS-2000 standard are commonly referred to as CDMA2000 1X, 1X, etc. The IS-856 (TIA-856) standard is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variations of CDMA. A TDMA system may implement a radio technology such as the Global System for Mobile Communications (GSM).An OFDMA system can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP LTE and LTE-advanced (LTE-A) are newer versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-a, and GSM are described in documents from an organization called the "3rd Generation Partnership Project" - 3GPP. CDMA2000 and UMB are described in documents from an organization called the "3rd Generation Partnership Project 2" - 3GPP2. The techniques described here can be used for the radio systems and technologies mentioned above, as well as for other radio systems and technologies.However, this document describes an LTE system for example purposes, and LTE terminology is used largely in the description above, although the techniques are applicable beyond LTE applications.

[00151] In LTE / LTE-A networks, including networks described herein, the term “evolved node B” (eNB) may generally be used to describe base stations. The wireless communications system or systems described herein may include a heterogeneous LTE / LTEA network in which different types of eNBs provide coverage for various geographic regions. For example, each eNB or base station may provide communication coverage for a macro cell, a small cell, or other cell types. “Cell” is a 3GPP term that may be used to describe a base station, a carrier or component carrier (CC) associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on the context.

[00152] Base stations may include, or may be referred to by those with technical expertise as, a base transceiver station, a radio base station, an access point (AP), a radio transceiver, NodeB, eN0deB (eNB), Home NodeB, Home eN0deB, or some other suitable terminology. The geographic coverage area of ​​a base station may be divided into sectors that constitute only a portion of the coverage area. The wireless communication system or systems described herein may include base stations of different types (e.g., macro-cell or small-cell base stations). The UEs described herein may be capable of communicating with various types of base stations and network equipment including macro-cell eNBs, small-cell eNBs, relay base stations, and the like. There may be overlapping geographic coverage areas for different technologies.In some cases, different coverage areas can be associated with different communication technologies. In some cases, the coverage area of ​​one communication technology may overlap with the coverage area associated with another technology. Distinct technologies can be associated with the same base station, or with different base stations.

[00153] A macro cell typically covers a relatively large geographic area (e.g., several kilometers in radius) and may allow UEs with service subscriptions from the network provider unrestricted access. A small cell is a lower-power base station compared to a macro cell that may operate in the same frequency bands or in different frequency bands (e.g., licensed, unlicensed, etc.) as macro cells. Small cells may include pico cells, femto cells, and micro cells, among other examples. A pico cell, for instance, may cover a small geographic area and may allow UEs with service subscriptions from the network provider unrestricted access.A femtocell can also cover a small geographic area (e.g., a house) and can provide UEs that have an association with the femtocell (e.g., UEs in a closed subscriber group (CSG), UEs for users in a house, and similar) with restricted access. An eNB for a macro cell can be referred to as a macro eNB. An eNB for a small cell can be referred to as a small cell eNB, pico eNB, femto eNB, or home eNB. An eNB can support one or more cells (e.g., two, three, four, and so on) (e.g., CCs). A UE may be able to communicate with various types of base stations and network equipment, including macro eNBs, small cell eNBs, relay base stations, and similar.

[00154] The wireless communication system or systems described herein may support synchronous or asynchronous operation. For synchronous operation, base stations may have similar frame synchronization, and transmissions from different base stations may be approximately time-aligned. For asynchronous operation, base stations may have different frame synchronization, and transmissions from different base stations may not be time-aligned. The techniques described herein may be used for synchronous or asynchronous operations.

[00155] The DL transmissions described herein may also be referred to as direct link transmissions, while the UL transmissions may also be referred to as reverse link transmissions. Each communication link described herein, including, for example, the 100 and 200 wireless communication systems of FIGS. 1 and 2, may include one or more carriers, wherein each carrier may be a signal consisting of multiple subcarriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent via a distinct subcarrier and may contain control information (e.g., reference signals, control channels, etc.), header information, user data, etc. The communication links described herein (e.g., the communication links of FIG. 125)1) They can transmit bidirectional communications using frequency division duplex (FDD) operation (e.g., using paired spectrum resources) or time-division duplex (TDD) operation (e.g., using unpaired spectrum resources). Frame structures can be defined for FDD (e.g., type 1 frame structure) and for TDD (e.g., type 2 frame structure).

[00156] Thus, aspects of disclosure can establish HARQ synchronization for reduced TTIs. It should be noted that these methods describe possible implementations and that operations and steps can be reorganized or modified so that other implementations are possible. In some examples, aspects of two or more of the methods can be combined.

[00157] The various illustrative blocks and modules described in relation to this disclosure may be implemented or executed with a general-purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA), or other discrete programmable logic device, logic gate or logic transistor, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other equivalent configuration).Thus, the functions described here can be performed by one or more other processing units (or cores) in at least one integrated circuit (IC). In many examples, different types of ICs can be used (e.g., Structured / Platform ASICs, an FPGA, or other semi-custom IC), which can be programmed in any way known in the art. The functions of each unit can also be implemented, in whole or in part, with instructions embedded in memory, formatted to be executed by one or more general-purpose or application-specific processors.

[00158] All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or that may subsequently become known to those possessing common expertise in the art are hereby expressly incorporated by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be made available to the public regardless of whether such disclosure is explicitly stated in the claims. The terms "module," "mechanism," "element," "device, component," and the like may not be substitutes for the word "means." Thus, no element of the claims should be interpreted as a means plus function unless the element is expressly mentioned by the phrase "means for."

[00159] In the attached figures, similar components or features may have the same reference label. In addition, several components of the same type can be differentiated by adding a dash to the reference label and a second label that distinguishes similar components. If only the first reference label is used in the specification, the description applies to any of the similar components that have the same first reference marker, regardless of the second reference marker.

Claims

2 / 6 is within the final part of a first time period having the first duration, and the second TTI is within the initial part of a second time period having the first duration.

2. A method according to claim 1, characterized in that the communication comprises: receiving a first TB during a first TTI and a second TB during a second TTI, wherein both the first TTI and the second TTI have the second duration; identifying the feedback time period based, at least in part, on the HARQ synchronization mode, wherein the HARQ synchronization mode comprises a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time.

3. A method according to claim 1, characterized in that one or more HARQ feedback messages comprise a first HARQ feedback message and a second HARQ feedback message distinct from the first HARQ feedback message.

4. A method according to claim 1, characterized in that a final portion of the first HARQ feedback message and an initial portion of the second HARQ feedback message are multiplexed using at least one of the following: an uplink control physical channel format, PUCCH, capable of carrying more than two bits; a bit split between the final portion of the first HARQ feedback message and the initial portion of the second HARQ feedback message; joint encoding of one or more bits of the first HARQ feedback message and the second HARQ feedback message; or a bit combination based, at least in part, on an orthogonal cover code, OCC, and at least one parity bit, or any combination thereof.

5. A method according to claim 1, characterized by further comprising: transmitting an indication of one or more UE capabilities to a base station, or further comprising: receiving an indication of a set of HARQ synchronization modes from a base station; and transmitting a HARQ synchronization mode request in response to the indication, wherein the HARQ synchronization mode is selected from the set of HARQ synchronization modes based, at least in part, on the HARQ synchronization mode request, or further comprising: indicating a set of second-duration transmissions with a downlink assignment index, DAI.

6. Method, according to claim 1, characterized by communication comprising: transmitting a first TB during a first TTI and a second TB during a second TTI, wherein both the first TTI and the second TTI have the second duration; Petition 870240017036, dated 29 / 02 / 2024, p. 7 / 13 4 / 6 identifying the feedback time period based, at least in part, on the HARQ synchronization mode, wherein the HARQ synchronization mode comprises a first HARQ response time and a second HARQ response time that is shorter than the first HARQ response time;and receive one or more HARQ feedback messages associated with the first or second TB during the feedback time period, wherein the one or more HARQ feedback messages are received during a first-duration TTI, or wherein the communication comprises: transmitting a first TB during a first TTI and a second TB during a second TTI, wherein the first TTI and the second TTI have the second duration; identifying the feedback time period based, at least in part, on the HARQ synchronization mode, wherein the HARQ synchronization mode comprises a first HARQ response time and a second HARQ response time that is equal to the first HARQ response time;and receive one or more HARQ feedback messages associated with the first or second TB during the feedback time period, wherein one or more HARQ feedback messages are received during a first duration TTI, or wherein communication using the HARQ synchronization mode is performed over a shared channel or a control channel, or wherein the first duration is a subframe duration and the second duration is a subframe slot duration. Petition 870240017036, dated 29 / 02 / 2024, p. 8 / 13 5 / 6; 7. A method according to claim 1, characterized by further comprising: identifying an uplink control configuration, UL, based at least in part on the HARQ synchronization mode; and transmitting an indication of the UL control configuration to the UE.

8. Method according to claim 1, characterized by further comprising: identifying a first uplink control physical channel resource shift, PUCCH, for UL transmissions using first-duration TTIs and a second PUCCH resource shift for UL transmissions using second-duration TTIs.

9. A method according to claim 8, characterized in that the second PUCCH resource shift is identified based, at least in part, on the first PUCCH resource shift and a delta value, or identifies a first scheduled downlink transmission indicator, DL, associated with first-duration TTIs and a second scheduled DL transmission indicator associated with second-duration TTIs.

10. A method according to claim 8, characterized in that the first PUCCH feature shift or the second PUCCH feature shift is identified based, at least in part, on a PUCCH shape.

11. Method, according to claim 10, characterized by one or more sets of features for UL transmissions being associated with each PUCCH format from a set of PUCCH formats, and wherein the one or more sets of features are each associated with a distinct base station or layer three configuration.

12. Wireless communication apparatus in a system that sustains transmission time intervals, TTIs, of a first duration and a second duration that is shorter than the first duration, characterized by comprising: means arranged to perform the steps of the method as defined in any one of claims 1 to 11.

13. Memory characterized by comprising instructions for wireless communication in a system that sustains transmission time intervals (TTIs) of a first duration and a second duration that is shorter than the first duration, the instructions being executable to perform the steps of the method as defined in any one of claims 1 to 11. Petition 870240017036, dated 29 / 02 / 2024, p. 10 / 13