Method and apparatus for triggering feedback retransmission in unlicensed spectrum

Abstract

A wireless communication system and method related to providing feedback for DL data are provided. A first wireless communication device communicates a first communication signal with a second wireless communication device. The first wireless communication device communicates a grant for retransmitting feedback associated with the first communication signal with the second wireless communication device. The first wireless communication device communicates the feedback with the second wireless communication device based on the grant.

Description

[0001] Z. Fan, Tao Luo, Xiaoxia Zhang, A. Chandramouli,

[0002] J. Sun, M.P. John Wilson, Yan Zhou, W. Nan

[0003] Cross - Reference to Related Applications and Priority Claim

[0004] This application claims the priority and benefit of U.S. Non - Provisional Patent Application No. 16 / 737,258, filed on January 8, 2020, which claims the priority and benefit of U.S. Provisional Patent Application No. 62 / 792,718, filed on January 15, 2019. Both of these applications are hereby incorporated by reference in their entirety. Technical Field

[0005] This application relates to wireless communication systems and, in particular, to conveying grants for retransmission feedback based on missed transmission opportunities (TXOPs).

[0006] Introduction

[0007] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems can be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). A wireless multi - access communication system may include several base stations (BSs), each of which simultaneously supports the communication of multiple communication devices, which may also be referred to as user equipment (UE).

[0008] To meet the growing demand for extended mobile broadband connectivity, wireless communication technologies are evolving from LTE technology to the next - generation New Radio (NR) technology. For example, NR is designed to provide lower latency, higher bandwidth or throughput, and higher reliability compared to LTE. NR is designed to operate over a wide range of frequency bands, such as from low - frequency bands below about 1 gigahertz (GHz) and mid - frequency bands from about 1 GHz to about 6 GHz, to high - frequency bands, such as millimeter - wave (mmWave) bands. NR is also designed to operate across different spectrum types from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrum to dynamically support high - bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0009] One way to avoid collisions when communicating in shared spectrum or unlicensed spectrum is to use a listen-before-talk (LBT) procedure to ensure that the shared channel is clear before transmitting a signal on the shared channel. For example, a transmitting node can listen to the channel to determine if there is an active transmission in the channel. When the channel is idle, the transmitting node can transmit a preamble to reserve a transmission opportunity (TXOP) in the shared channel and can communicate with a receiving node during the TXOP.

[0010] Brief overview of some examples

[0011] The following presents an overview of some aspects of the present disclosure to provide a basic understanding of the technologies discussed. This overview is not an exhaustive survey of all contemplated features of the present disclosure, and is neither intended to identify key or critical elements of all aspects of the present disclosure nor to attempt to define the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in overview form as a prelude to the more detailed description that follows.

[0012] For example, in one aspect of the present disclosure, a wireless communication method includes: communicating a first communication signal by a first wireless communication device with a second wireless communication device; communicating a grant for retransmitting feedback associated with the first communication signal by the first wireless communication device with the second wireless communication device; and communicating the feedback by the first wireless communication device with the second wireless communication device based on the grant.

[0013] In an additional aspect of the present disclosure, an apparatus includes a transceiver configured to: communicate a first communication signal with a second wireless communication device; communicate a grant for retransmitting feedback associated with the first communication signal with the second wireless communication device; and communicate the feedback with the second wireless communication device based on the grant.

[0014] In an additional aspect of the present disclosure, for a computer-readable medium having program code recorded thereon, the program code includes: code for causing a first wireless communication device to communicate a first communication signal with a second wireless communication device; code for causing the first wireless communication device to communicate a grant for retransmitting feedback associated with the first communication signal with the second wireless communication device; and code for causing the first wireless communication device to communicate the feedback with the second wireless communication device based on the grant.

[0015] In an additional aspect of the present disclosure, an apparatus includes: means for communicating a first communication signal with a second wireless communication device; means for communicating a grant for retransmitting feedback associated with the first communication signal with the second wireless communication device; and means for communicating the feedback with the second wireless communication device based on the grant.

[0016] After reading the following description of specific example embodiments of the present disclosure in conjunction with the accompanying drawings, other aspects, features, and embodiments of the present disclosure will be apparent to those of ordinary skill in the art. Although the features of the present disclosure may be discussed below with respect to certain embodiments and drawings, all embodiments of the present disclosure may include one or more of the advantageous features discussed herein. In other words, although one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the present disclosure discussed herein. In a similar manner, although example embodiments may be discussed below as device, system, or method embodiments, it should be appreciated that such example embodiments may be implemented in a variety of devices, systems, and methods. Brief Description of the Drawings

[0018] Figure 1 Illustrates a wireless communication network according to some embodiments of the present disclosure.

[0019] Figure 2 Illustrates a communication scheme for conveying grants for retransmission feedback according to some embodiments of the present disclosure.

[0020] Figure 3 Illustrates a communication scheme for conveying grants for retransmission feedback according to some embodiments of the present disclosure.

[0021] Figure 4 Illustrates a communication scheme for conveying grants for retransmission feedback according to some embodiments of the present disclosure.

[0022] Figure 5 Is a block diagram of an example user equipment (UE) according to embodiments of the present disclosure.

[0023] Figure 6 Is a block diagram of an example base station (BS) according to embodiments of the present disclosure.

[0024] Figure 7 Is a flowchart of a method for conveying grants for retransmission feedback according to some embodiments of the present disclosure.

[0025] Detailed Description

[0026] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0027] The present disclosure generally relates to wireless communication systems (also referred to as wireless communication networks). In various embodiments, techniques and apparatus may be used in wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, fifth generation (5G) or new radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" may be used interchangeably.

[0028] OFDMA networks may implement radio technologies such as evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM, etc. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), while cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These various radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a cooperation between groups of telecommunications associations that aims to define globally applicable third generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the Universal Mobile Telecommunications System (UMTS) mobile phone standard. 3GPP may define specifications for next-generation mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution from LTE, 4G, 5G, NR, and beyond wireless technologies, which have shared access to the wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

[0029] Specifically, 5G networks envision diverse deployments, diverse spectrums, and diverse services and devices that can be achieved using an OFDM-based unified air interface. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to provide coverage for: (1) having an ultra-high density (e.g., about 1M nodes / km 2) Ultra-low complexity (e.g., about dozens of bits per second), ultra-low energy (e.g., about 10+ years of battery life), and deep coverage for large-scale Internet of Things (IoT) capable of reaching challenging locations; (2) Critical mission control including users with strong security (to protect sensitive personal, financial, or confidential information), ultra-high reliability (e.g., about 99.9999% reliability), ultra-low latency (e.g., about 1 ms), and a wide range of mobility or lack of mobility; and (3) Enhanced mobile broadband, which includes extremely high capacity (e.g., about 10 Tbps / km 2 ), extreme data rates (e.g., multi-Gbps rates, 100+ Mbps user experience rate), and deep awareness with advanced discovery and optimization.

[0030] 5G NR can be implemented to: use an optimized OFDM-based waveform with scalable parameter sets and transmission time intervals (TTIs); have a common, flexible framework to efficiently multiplex services and features using a dynamic, low-latency time-division duplex (TDD) / frequency-division duplex (FDD) design; and have advanced radio technologies such as massive multiple-input multiple-output (MIMO), robust millimeter-wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of parameter sets (and the scaling of subcarrier spacing) in 5G NR can efficiently address operating diverse services across diverse spectrums and diverse deployments. For example, in various outdoor and macro-coverage deployments with less than 3 GHz FDD / TDD implementations, the subcarrier spacing can occur at 15 kHz, e.g., on 1, 5, 10, 20 MHz, etc. BW. For other various outdoor and small cell coverage deployments with TDD greater than 3 GHz, the subcarrier spacing can occur at 30 kHz on 80 / 100 MHz BW. For other various indoor broadband implementations, by using TDD in the unlicensed part of the 5 GHz band, the subcarrier spacing can occur at 60 kHz on 160 MHz BW. Finally, for various deployments using mmWave components with TDD at 28 GHz, the subcarrier spacing can occur at 120 kHz on 500 MHz BW.

[0031] The scalable parameter sets of 5G NR enable scalable TTIs to meet diverse latency and Quality of Service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs allows transmissions to start at symbol boundaries. 5G NR also contemplates a self - contained integrated subframe design with uplink (UL) / downlink (DL) scheduling information, data, and acknowledgments in the same subframe. The self - contained integrated subframe supports communication in unlicensed or contention - based shared spectrum, and supports adaptive UL / DL that can be flexibly configured on a per - cell basis to dynamically switch between UL and DL to meet current traffic needs.

[0032] Various other aspects and features of the present disclosure are further described below. It should be apparent that the teachings herein can be embodied in a variety of forms, and any specific structure, function, or both disclosed herein are merely representative and not limiting. Based on the teachings herein, one of ordinary skill in the art should appreciate that the aspects disclosed herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of the aspects set forth herein can be used to implement an apparatus or practice a method. Additionally, other structures, functionality, or a combination of structures and functionality that are complementary to or different from one or more of the aspects set forth herein can be used to implement such an apparatus or practice such a method. For example, a method can be implemented as part of a system, device, apparatus, and / or as instructions stored on a computer - readable medium for execution on a processor or computer. Moreover, one aspect can include at least one element of a claim.

[0033] Figure 1 A wireless communication network 100 in accordance with some embodiments of the present disclosure is illustrated. Network 100 can be a 5G network. Network 100 includes several base stations (BSs) 105 and other network entities. A BS 105 can be a station that communicates with a UE 115 and can also be referred to as an evolved Node B (eNB), a next - generation eNB (gNB), an access point, etc. Each BS 105 provides communication coverage for a specific geographic area. In 3GPP, the term "cell" can refer to the specific geographic coverage area of the BS 105 and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0034] BS105 can provide communication coverage for macro cells or small cells (such as pico cells or femto cells), and / or other types of cellular cells. A macro cell generally covers a relatively large geographical area (e.g., with a radius of several kilometers) and may allow unconstrained access by UEs having a service subscription with a network provider. A small cell (such as a pico cell) generally covers a relatively small geographical area and may allow unconstrained access by UEs having a service subscription with a network provider. A small cell (such as a femto cell) generally also covers a relatively small geographical area (e.g., a residence), and in addition to unconstrained access, it may be available for constrained access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the residence, etc.). The BS for a macro cell may be referred to as a macro BS. The BS for a small cell may be referred to as a small cell BS, pico BS, femto BS, or home BS. In Figure 1 the example shown, BS105d and 105e may be conventional macro BSs, while BS105a - 105c may be macro BSs enabled with one of three-dimensional (3D), full-dimensional (FD), or massive MIMO. BS105a - 105c may utilize their higher-dimensional MIMO capabilities to increase coverage and capacity by using 3D beamforming in both elevation and azimuth beamforming. BS105f may be a small cell BS, which may be a home node or a portable access point. BS105 may support one or more (e.g., two, three, four, etc.) cellular cells.

[0035] Network 100 may support synchronous or asynchronous operation. For synchronous operation, each BS may have a similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, each BS may have a different frame timing, and transmissions from different BSs may not be aligned in time.

[0036] The UEs 115 are dispersed throughout the wireless network 100, and each UE 115 can be stationary or mobile. The UE 115 can also be referred to as a terminal, mobile station, subscriber unit, station, etc. The UE 115 can be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, wireless local loop (WLL) station, etc. In one aspect, the UE 115 can be a device that includes a universal integrated circuit card (UICC). In another aspect, the UE can be a device that does not include a UICC. In some aspects, the UE 115 that does not include a UICC can also be referred to as an IoT device or an Internet of Everything (IoE) device. The UEs 115a - 115d are examples of mobile smart phone type devices that access the network 100. The UE 115 can also be a machine specifically configured for connected communications, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc. The UEs 115e - 115k are examples of various machines configured to communicate with the network 100. The UE 115 can be capable of communicating with any type of BS, whether it is a macro BS or a small cell, etc. In Figure 1 In it, lightning bolts (e.g., communication links) indicate wireless transmissions between the UE 115 and the serving BS 105, or desired transmissions between BSs and backhaul transmissions between BSs. The serving BS 105 is the BS designated to serve the UE 115 on the DL and / or UL.

[0037] In operation, the BSs 105a - 105c can use 3D beamforming and coordinated spatial techniques, such as coordinated multi-point (CoMP) or multi-connectivity, to serve the UEs 115a and 115b. The macro BS 105d can perform backhaul communications with the BSs 105a - 105c and with the small cell BS 105f. The macro BS 105d can also transmit multicast services subscribed to and received by the UEs 115c and 115d. Such multicast services can include mobile TV or streaming video, or can include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or Gray alerts.

[0038] Network 100 may also support mission-critical communications with ultra-reliable and redundant links for mission-critical devices such as UE 115e, which may be a drone. The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, as well as a link from small cell BS 105f. Other machine type devices such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device) may communicate directly with BSs such as small cell BS 105f and macro BS 105e via network 100, or may be in a multi-hop configuration by communicating with another user equipment that relays their information to the network (such as UE 115f communicating temperature measurement information to smart meter UE 115g, which is then reported to the network via small cell BS 105f). Network 100 may also provide additional network efficiency via dynamic, low latency TDD / FDD communications such as in vehicle-to-vehicle (V2V).

[0039] In some implementations, network 100 utilizes an OFDM-based waveform for communication. An OFDM-based system may divide the system BW into multiple (K) orthogonal subcarriers, which are typically also referred to as subcarriers, frequency tones, frequency bins, etc. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system BW. The system BW may also be divided into subbands. In other instances, the subcarrier spacing and / or the duration of the TTI may be scalable.

[0040] In one embodiment, BS 105 may assign or schedule (e.g., in the form of time-frequency resource blocks (RBs)) transmission resources for DL and UL transmissions in network 100. DL refers to the transmission direction from BS 105 to UE 115, while UL refers to the transmission direction from UE 115 to BS 105. This communication may take the form of radio frames. A radio frame may be divided into multiple subframes, e.g., about 10. Each subframe may be divided into time slots, e.g., about 2. Each time slot may be further divided into sub-slots. In FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in the UL frequency band and a DL subframe in the DL frequency band. In TDD mode, UL and DL transmissions occur in different time periods using the same frequency band. For example, a subset of subframes in a radio frame (e.g., DL subframes) may be used for DL transmissions, and another subset of subframes in the radio frame (e.g., UL subframes) may be used for UL transmissions.

[0041] DL subframes and UL subframes can be further divided into several regions. For example, each DL or UL subframe may have predefined regions for the transmission of reference signals, control information, and data. A reference signal is a predefined signal that facilitates communication between BS105 and UE 115. For example, a reference signal may have a specific pilot pattern or structure, where the pilot frequency tones may span the operating BW or frequency band, and each pilot frequency tone is located at a predefined time and a predefined frequency. For example, BS105 may transmit cell-specific reference signals (CRS) and / or channel state information reference signals (CSI-RS) so that UE 115 can estimate the DL channel. Similarly, UE 115 may transmit sounding reference signals (SRS) so that BS105 can estimate the UL channel. Control information may include resource assignment and protocol control. Data may include protocol data and / or operational data. In some embodiments, BS105 and UE 115 may use self-contained subframes to communicate. A self-contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe may be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for DL communication.

[0042] After establishing a connection, UE 115 and BS105 may enter a normal operation phase, during which operational data may be exchanged. For example, BS105 may schedule UE 105 for UL and / or DL communication. BS105 may transmit UL and / or DL scheduling grants to UE 115 via the physical DL control channel (PDCCH). BS105 may transmit DL communication signals to UE 115 via the physical DL shared channel (PDSCH) according to the DL scheduling grant. UE 115 may transmit UL communication signals to BS105 via the physical UL shared channel (PUSCH) and / or the physical UL control channel (PUCCH) according to the UL scheduling grant.

[0043] BS105 and UE 115 can further communicate based on DL transmission parameters and feedback transmission parameters corresponding to a TXOP. The DL transmission parameters indicate the time period between a DL grant and the corresponding DL transmission. The feedback transmission parameters indicate the time period between DL data reception and the corresponding feedback for the DL data. The feedback signal can correspond to ACK or NACK transmission. The DL transmission parameters and the feedback transmission parameters can be preconfigured by the network and can be indicated on a per-slot basis. In the context of LTE or NR, the DL transmission parameters and the feedback transmission parameters can be indicated in DL control information (DCI) carried in the PDCCH. For example, if BS105 reserves a TXOP, the DL transmission parameters can indicate a value of zero, and the feedback transmission parameters can indicate a value of four. The DL transmission parameters can be greater than zero, and the feedback transmission parameters can be less than or greater than four.

[0044] In one embodiment, network 100 can be an NR network deployed in licensed spectrum. Network 100 can operate on a shared channel (which can include a shared band or an unlicensed band) at a higher frequency, such as at approximately 3.5 gigahertz (GHz), sub-6 GHz, or millimeter wave bands. In such embodiments, wireless communication devices can share resources in the shared communication medium and can employ a listen-before-talk (LBT) procedure to reserve a transmission opportunity (TXOP) in the shared medium for communication. A TXOP can be discontinuous in time and can refer to the amount of time during which a station can transmit frames when it wins contention for the wireless medium. Each TXOP can include multiple time slots and one or more medium sensing periods.

[0045] Wireless communication devices can perform LBT in the shared channel. When LBT results in an LBT pass (the wireless communication device wins contention for the wireless medium), the wireless communication device can access the shared medium to transmit and / or receive data. In one example, the wireless communication device is BS105. When LBT results in an LBT pass, BS105 can schedule UE 115 to communicate on the shared channel during a TXOP. In another example, BS105 can transmit DL data to UE 115 and / or information about the time-domain resource location for feedback transmission for the DL data. In the present disclosure, the time-domain resource can also be referred to as a feedback opportunity. Further, UE 115 can receive DL data from BS105 and transmit feedback for the DL data to BS105. The feedback can be an acknowledgement (ACK) indicating that the UE successfully received the DL data (e.g., received the DL data without error) or can be a negative acknowledgement (NACK) indicating that the UE did not successfully receive the DL data (e.g., including errors or error correction failures).

[0046] In another example, the wireless communication device is UE 115. When LBT results in a successful LBT, UE 115 may receive DL data from BS105 and / or time-domain resource location information regarding feedback opportunities for the DL data. UE 115 may use the feedback opportunity to transmit feedback for the DL data to BS105. The feedback transmission of UE 115 complies with LBT constraints. Before transmitting the feedback, UE 115 may perform LBT that results in an LBT failure (the UE does not win the contention for the wireless medium). Accordingly, the UE may miss the opportunity to transmit the feedback, and BS will not receive the feedback as expected. The feedback that BS105 expects but does not receive may be referred to as failed feedback.

[0047] The present disclosure provides techniques for conveying grants for feedback retransmission. In some examples, BS105 provides a grant to trigger retransmission of failed feedback. It may be beneficial for BS105 to provide a retransmission grant for failed feedback to UE 115 because the ability of UE115 to transmit feedback on UL transmissions depends on whether UE 115 can obtain access to the medium for data transmission and / or reception. By providing UE 115 with another opportunity to provide the failed feedback to BS105, UE 115 is more likely to be able to retransmit the failed feedback to BS105. Additionally, instead of transmitting DL data to UE 115 again, BS105 can save resources and transmit to UE 115 a grant for retransmitting feedback associated with the DL data. Accordingly, spectrum sharing performance can be improved and feedback latency and / or retransmission scheduling latency can be reduced.

[0048] Figure 2 A communication scheme 200 for conveying grants for retransmitting feedback in accordance with some embodiments of the present disclosure is illustrated. Communication scheme 200 may correspond to a communication scheme between BS105 and UE 115 of network 100. In Figure 2 , the x-axis represents time in certain constant units. Figure 2 Structures 201, 221 of TXOPs 202, 222 in a shared channel are respectively shown. TXOPs 202, 222 respectively include a plurality of time slots 204, 214 in time. The number of time slots within a TXOP may vary depending on the embodiment.

[0049] For simplicity of explanation and discussion, Figure 2It is explained that the TXOPs 202, 222 include ten time slots 204, 214 indexed from S0 to S9. The BS can communicate with the UE on a time-slot basis. A time slot may also be referred to as a TTI. Each time slot or TTI carries a Media Access Control (MAC) layer transport block. Each time slot may include several symbols in time and several frequency tones in frequency. Each time slot may include a DL control portion followed by at least one of a subsequent DL data portion, a UL data portion, and / or a UL control portion. In the context of LTE or NR, the DL control portion, the DL data portion, the UL data portion, and the UL control portion may be referred to as PDCCH, PDSCH, PUSCH, and PUCCH, respectively.

[0050] The patterned-filled boxes indicate the transmission of DCI, DL data, UL data, ACK, and / or NACK in the corresponding time slots. Although the entire time slot is patterned-filled, the transmission may occur only in the corresponding portion of the time slot. Additionally, an "X" in the box indicates a failed transmission (e.g., due to LBT failure). In the present disclosure, a second attempt to transmit feedback may be referred to as a retransmission of the feedback.

[0051] The BS contending for the TXOP in the shared channel may perform LBT in the shared channel. If LBT results in LBT passing, the BS 105 may transmit DCI 220 in the time slot 204 indexed as S1 (e.g., in the DL control portion of the time slot 204). The DCI 220 may indicate a DL grant for the UE 115 in the same time slot 204 indexed as S1 (e.g., K0 = 0). Accordingly, the BS 105 transmits a DL data signal 224 to the UE 115 in the time slot 204 indexed as S1 (e.g., in the DL data portion of the time slot 204). The UE may receive the DCI 220 and receive the DL data signal 224 based on the DL grant.

[0052] After receiving the DL data signal 224, the UE 115 may transmit feedback for the DL data signal 224 to the BS105. The BS105 may provide the UE 115 with a feedback opportunity for the DL data signal 224 in the time slot 204 with index S5. The feedback opportunity may refer to a resource location (e.g., a time-frequency resource) during which the UE 115 may provide feedback (e.g., ACK / NACK) for the DL data signal. The feedback opportunity may be transmitted at different positions within a time domain resource. The Acknowledgment Resource Indicator (ARI) may convey the resource location of the feedback opportunity and may be, for example, a resource block. Accordingly, the BS105 may be configured via the TXOP structure to configure a feedback opportunity for the UE 115 to transmit feedback for the DL data signal 224. The BS105 may indicate the resource (e.g., time slot) (e.g., in the time slot 204 with index S5) that may be used by the UE 115 to provide feedback. The resource may be provided via the TXOP structure configuration and / or control channel information detected by the UE 115. The BS 105 may indicate the time domain resource location information for the feedback opportunity as the time slot 204 with index S5. Accordingly, the UE 115 may use the time slot 204 with index S5 to transmit feedback for the DL data signal 224.

[0053] This feedback may report the reception status of the DL data signal 224 to the BS 105 by transmitting an ACK / NACK signal 228 in the time slot 204 with index S5 (e.g., in the UL data portion or UL control portion of the time slot 204) based on the ARI. The time slot 204 with index S5 is the fourth time slot starting from the time slot 204 with index S1. The ACK / NACK signal 228 refers to a feedback signal carrying an ACK or NACK for the DL data signal 224. When the reception of the DL data signal 224 is successful (e.g., the DL data is received without error), the UE 115 may transmit an ACK. Alternatively, when the reception of the DL data signal 224 is unsuccessful (e.g., includes an error or the error correction fails), the UE may transmit a NACK.

[0054] The ACK / NACK signal 228 may be associated with a Hybrid Automatic Repeat reQuest (HARQ) process. In a HARQ process, a transmitting node may transmit various encoded versions of information data to a receiving node. For example, the transmitting node may transmit a first encoded version of the information data to the receiving node. Upon receiving a NACK signal from the receiving node, the transmitting node may transmit a second encoded version of the information data to the receiving node. When both the received first encoded version and the received second encoded version have errors, the receiving node may combine the received first encoded version and the received second encoded version for error correction.

[0055] The UE may perform LBT in the shared channel before a feedback opportunity (e.g., time slot 204 indexed as S5). The ability of UE 115 to transmit the ACK / NACK signal 228 during the configured feedback opportunity depends on whether the UE can obtain access to the medium for data transmission and / or reception. If LBT results in LBT passing, UE 115 may transmit the ACK / NACK signal 228 in time slot 204 indexed as S5. Alternatively, if LBT results in LBT failure, UE 115 may be unable to transmit the ACK / NACK signal 228 based on the missed TXOP. Accordingly, BS105 does not receive the ACK / NACK signal 228 at the expected time (e.g., in time slot 204 indexed as S5). In Figure 2 the illustrated example, time slot 204 indexed as S5 is marked with an "X", indicating that UE 115 is unable to transmit the ACK / NACK signal 228 to BS105.

[0056] If BS105 does not receive the ACK / NACK signal 228 from UE 115 as expected, instead of retransmitting the DL data signal 224 to UE 115, BS105 may explicitly trigger a PUCCH report (e.g., retransmit the feedback for the DL data signal 224). For example, BS105 may transmit a grant communication signal to UE 115 indicating a grant for retransmitting the failed feedback associated with the DL data signal 224. In this way, UE 115 may receive a trigger indicating that the failed feedback for the DL data signal 224 is to be retransmitted.

[0057] Referring to TXOP 222, parameter 210 may indicate a value of zero (e.g., K0 = 0), and parameter 212 may indicate a value of three (e.g., K1 = 3). Before transmitting in the shared channel, BS105 performs LBT. If LBT results in LBT passing, BS105 may transmit DCI 240 to UE 115 in time slot 214 indexed as S0 (e.g., in the DL control section of time slot 214). DCI 240 may indicate a grant for retransmitting the failed ACK / NACK signal 228 associated with the DL data signal 224. UE 115 may receive DCI 240 indicating a grant for retransmitting the failed ACK / NACK signal 228 and accordingly transmit the ACK / NACK signal 228 to BS105 based on the grant. DCI 240 may indicate an ARI that references time slot 214 indexed as S3 for the transmission of the ACK / NACK signal 228. UE 115 may transmit the ACK / NACK signal 228 to BS105 in time slot 214 indexed as S3 (e.g., in the UL data section or UL control section of time slot 214).

[0058] In some examples, BS105 may combine the grant for retransmitting ACK / NACK signal 228 with a DL grant. For example, DCI 240 may indicate the grant for retransmitting ACK / NACK signal 228 and may also indicate a DL grant for UE 115 in the same time slot 214 with index S0 (e.g., K0 = 0). BS105 transmits DL data signal 244 to UE 115 in time slot 214 with index S0 (e.g., in the DL data portion of time slot 214) based on this DL grant. The UE may receive DCI240 (which indicates the grant for retransmitting ACK / NACK signal 228 and the DL grant), and the DL data signal 244 based on the same grant indicated in DCI 240. In this example, UE 115 may transmit ACK / NACK signal 228 in time slot 214 with index S3 (e.g., in the UL data portion or UL control portion of time slot 214), and may also transmit ACK / NACK signal 246 in time slot 214 with index S4 (e.g., K1 = 3) (e.g., in the UL data portion or UL control portion of time slot 214). ACK / NACK signal 246 indicates the reception of DL data signal 244 by UE 115. DCI 240 may indicate an ARI that references time slot 214 with index S4 for the transmission of ACK / NACK signal 246. The ARI that references time slot 214 with index S3 for the transmission of ACK / NACK signal 228 may be the same as or different from the ARI that references time slot 214 with index S4 for the transmission of ACK / NACK signal 246.

[0059] ACK / NACK signal 228 and ACK / NACK signal 246 are shown as being transmitted in different time slots (e.g., time slots 214 with indices S3 and S4 respectively). It should be understood that in other examples, ACK / NACK signal 228 and ACK / NACK signal 246 may be transmitted in the same time slot. Additionally, as will be further explained below with respect to Figure 3 and 4 the transmissions of ACK / NACK signal 228 and ACK / NACK signal 246 may have the same or different spatial relation information with respect to each other. Further, although DCI is described as indicating an ARI that references a specific time slot for transmission within a TXOP, it should be understood that DCI may indicate a feedback transmission parameter that indicates the time period between DL data reception and the corresponding feedback for that DL data.

[0060] Figure 3A communication scheme 300 for conveying grants for retransmission feedback in accordance with some embodiments of the present disclosure is explained. The communication scheme 300 may be employed by a UE (such as UE 115) and a BS (such as BS105) in a network (such as network 100). In Figure 3 this, BS105 may perform LBT 302 to obtain a TXOP 304 for DL transmission to UE 115 in PDSCH 306. The checkmark shown in the LBT indicates that the LBT has passed, and the "X" shown in the LBT indicates that the LBT has failed. The checkmark shown in LBT 302 indicates that LBT 302 has resulted in the LBT passing. Accordingly, BS105 transmits a DL transmission to UE 115 via PDSCH 306.

[0061] UE 115 may receive PDSCH 306 from BS105 and may desire to transmit feedback associated with PDSCH 306 to BS105. BS105 may configure UE 115 with a feedback opportunity 314 in slot m for transmitting feedback for PDSCH 306. Prior to transmitting the feedback opportunity 314, UE 115 may perform LBT 312. LBT 312 results in the LBT failing. Accordingly, UE115 is unable to transmit PUCCH 316a in slot m based on missing the feedback opportunity 314.

[0062] BS105 may expect to receive PUCCH 316a in slot m during the feedback opportunity 314. In response to determining that the feedback for PDSCH 306 (e.g., PUCCH 316a) has failed, BS105 may trigger a retransmission of the feedback. BS105 may perform LBT 322 to obtain a TXOP 324 to transmit PDCCH 326 to UE 115. The checkmark shown in LBT 322 indicates that LBT 322 has resulted in the LBT passing. PDCCH 326 may indicate a trigger for retransmitting the failed feedback for PDSCH 306 (e.g., the failed PUCCH 316a). In the sense that a grant for PDSCH 306 has been transmitted to UE 115 (e.g., the BS may have indicated a grant during TXOP304) and / or UE 115 has attempted to transmit PUCCH 316a, PDCCH 326 may indicate a grant for retransmitting the failed feedback. In some examples, the grant indicated by PDCCH 326 may indicate UL resources for retransmitting PUCCH316a (e.g., ACK / NACK for a previous PDSCH 306).

[0063] UE 115 may receive a PDCCH 326 that indicates a grant for retransmitting feedback associated with the PDSCH 306. UE 115 may perform LBT 332 based on the grant for retransmitting feedback (e.g., PUCCH 316a) indicated in the PDCCH 326 to obtain a feedback opportunity 334 to transmit the PUCCH 316b. The checkmark shown in LBT 332 indicates that LBT 332 results in LBT passing. UE 115 may transmit the PUCCH 316b in slot n during the feedback opportunity 334. The PUCCH 316b may include the same feedback as the PUCCH 316a, and "retransmitting" the PUCCH 316a may refer to transmitting the PUCCH 316b. Additionally, to further distinguish between the PUCCH 316a and the PUCCH 316b, the PUCCH 316a may also be referred to as the failed PUCCH 316a.

[0064] Additionally, the PDCCH 326 may indicate a DL grant associated with a new PDSCH 328. The BS 105 may transmit the new PDSCH 328 to the UE 115 during the TXOP 324 (e.g., in the DL data portion of the slot). UE 115 may receive the new PDSCH 328 based on the DL grant indicated by the PDCCH 326. The PDCCH 326 may indicate a new feedback grant for transmitting feedback for the PDSCH 328. In some examples, the triggering for failed feedback (e.g., PUCCH 316a) may be combined with the new feedback grant associated with the new PDSCH 328.

[0065] After the UE 115 receives the new PDSCH 328, the UE 115 may transmit a new PUCCH 336 based on the new feedback grant indicated in the PDCCH 326. The new PUCCH 336 may be feedback for the new PDSCH 328. Accordingly, the transmissions of the PUCCH 316b and the new PUCCH 336 may be triggered by the same grant. Additionally, the PUCCH 316b and the new PUCCH 336 correspond to different PDSCHs. In one example, the PUCCH 316b indicates feedback for the PDSCH 306, and the new PUCCH 336 indicates feedback for the new PDSCH 328. Accordingly, in some examples, the grant indicated by the PDCCH 326 may indicate a first UL resource for retransmitting the PUCCH 316a (e.g., ACK / NACK for the previous PDSCH 306), a DL resource for new DL data (e.g., the new PDSCH 328), and a second UL resource for a new PUCCH transmission (e.g., the new PUCCH 336).

[0066] Although the UE 115 may transmit the PUCCH 316b and the new PUCCH 336 in the same time slot n during the feedback opportunity 334 (as Figure 3 shown), it should also be understood that the BS may configure the UE 115 to transmit the PUCCH 316b and the new PUCCH 336 in different time slots (e.g., n and n+1, as Figure 2 shown). The time slots between the PUCCH 316b and the new PUCCH 336 transmissions may be spaced according to the ARI. Additionally, the resources for the PUCCH 316b and the new PUCCH 336 triggered in the same grant may be configured separately by two ARIs or linked together. Different bits may be used to indicate the time-domain resource location information. In one example, a single ARI field may indicate the time-domain resource location for both the PUCCH 316b and the new PUCCH 336 transmissions. In another example, two different ARI fields may indicate the time-domain resource locations for the PUCCH 316b and the new PUCCH 336 transmissions.

[0067] Furthermore, although the PUCCH 316a associated with the feedback opportunity 314 and the PUCCH 316b associated with the feedback opportunity 334 are shown in the same time slot (e.g., time slot n, as Figure 3 shown), it should be understood that the PUCCH 316a and the PUCCH 316b may be transmitted in different time slots (as Figure 2 shown). For example, the UE 115 may have attempted to transmit the PUCCH 316a in time slot m during the feedback opportunity 314 and may transmit the PUCCH 316b in time slot n during the feedback opportunity 334, where m and n correspond to different time slots in the TXOP configured by the BS.

[0068] Additionally, in some examples, BS105 may coordinate with UE 115 to collaboratively schedule data, beamform data, and / or transmit data in network 100. Considerable gains can be achieved by making more use of multi-antenna systems. For example, in millimeter-wave access, a large number of antenna elements may be used to take advantage of the shorter wavelengths and enable beamforming and beam tracking. When using, for example, millimeter-wave frequencies, beamforming may be used to avoid transmission losses. Beamforming combines signals from multiple antenna elements in an antenna array such that the combined signal level increases when several signal phases are aligned (constructive interference). Each signal from each antenna element is transmitted with a slightly different phase (delay) to create a beam pointed at the receiver. At higher frequencies, propagation and penetration losses are higher. Beamforming techniques can be used to increase the signal level received by a device. The beamforming side combines energy over its aperture, thus obtaining a certain antenna gain in a given direction while having attenuation in other directions. Each of BS105 and UE 115 can direct its energy in a specific direction. Different transmission beams may correspond to different beam patterns.

[0069] Additionally, the BS may configure the UE 115 with different spatial parameters (e.g., beam direction) for transmitting PUCCH 316b and PUCCH 336. Thus, the UE 115 can direct its energy in a specific direction during PUCCH transmission according to these spatial parameters. In Figure 3In the example being illustrated, the UE 115 may transmit PUCCH on different beam directions. The terms "transmission beam" and "beam" may be used interchangeably in this disclosure. The UE 115 may include an antenna element array and may configure the antenna element array to form a transmission beam 311 in a specific direction. The transmission beams 311a, 311b, ……, and 311n have different patterns. The UE 115 may have attempted to transmit PUCCH 316a on the transmission beam 311a (e.g., shown as hatched) pointed in the direction 340. During the feedback opportunity 334, the UE 115 may transmit PUCCH 316b on the transmission beam 311b (e.g., shown as hatched) pointed in the direction 342. The UE 115 may also transmit a new PUCCH 336 on the transmission beam 311b pointed in the direction 342. In this example, the PUCCH 316a associated with the feedback opportunity 314 and the PUCCH 316b associated with the feedback opportunity 334 may have different spatial relation information. In another example, the PUCCH 316a and the PUCCH 316b may have the same spatial relation information. In this example, the UE 115 may have attempted to transmit PUCCH 316a on the same transmission beam (e.g., transmission beam 311a) as the UE 115 used to transmit PUCCH 316b. Additionally, the PUCCH 316b and the new PUCCH 336 triggered in the same grant may have the same or different spatial relation information relative to each other.

[0070] Figure 4 A communication scheme 400 for conveying a grant for retransmission feedback in accordance with some embodiments of the present disclosure is illustrated. The communication scheme 400 may be employed by a UE (such as the UE 115) and a BS (such as the BS 105) in a network (such as the network 100). Figure 4 Shows some aspects from Figure 3 For example, the BS 105 transmits the PDSCH 306. The UE 115 fails to transmit the PUCCH 316a on the transmission beam 311a (e.g., shown as hatched) pointed in the direction 340 in the time slot m. Additionally, the BS 105 transmits the PDCCH 326 and a new PDSCH 328. The UE 115 receives the PDCCH 326 and the new PDSCH 328 from the BS 105. The PDCCH 326 may indicate a grant for retransmitting the feedback associated with the PDSCH 306. The PDCCH 326 may also indicate a grant regarding the new PDSCH 328 and the feedback for the new PDSCH 328.

[0071] In Figure 4In the example being explained, UE 115 transmits PUCCH 316b on transmission beam 311b (e.g., shown as hatched) in the direction of arrow 342 during feedback opportunity 334 in time slot n. As discussed, UE 115 attempted to transmit PUCCH 316a in time slot m during a feedback opportunity, where m and n correspond to different time slots within the TXOP. Additionally, UE 115 transmits a new PUCCH 336 on transmission beam 311a (e.g., shown as hatched) in the direction of arrow 340 during feedback opportunity 334 in time slot n+1. Accordingly, UE 115 may transmit PUCCH 316b and the new PUCCH 336 in different time slots and / or using different beam patterns.

[0072] If BS105 determines that feedback from UE 115 has failed, BS105 may trigger a PUCCH report from UE 115. BS105 may request that UE 115 include, for example, the payload size of the failed feedback (e.g., PUCCH 316a), a bit mask of DL grants reported in the failed feedback, and / or the payload of the failed feedback. In one example, the grant may request that UE 115 provide the payload size of the failed feedback, a bit mask of DL grants reported in the failed feedback, and / or the payload of the failed feedback as well as other information.

[0073] The payload size of the failed feedback associated with the communication signal corresponds to the number of ACK / NACKs for the communication signal, and the payload of the failed feedback may refer to the ACK / NACKs for the communication signal. In some examples, the failed PUCCH 316a may include feedback for one or more PDSCHs. If BS105 does not receive PUCCH 316a, there may be an ambiguity regarding the payload size between BS105 and UE 115 such that BS105 does not correctly decode PUCCH 316a. Accordingly, in the triggered retransmission, BS105 may request that UE 115 send the payload size of the failed PUCCH 316a. The bit mask may indicate which DL grants UE 115 has received within a time window. The bit mask may be used to indicate which grants (e.g., PDSCH) UE 115 has received for the same original PUCCH feedback. Based on the bit mask, BS105 may determine the payload size of the previously received PUCCH.

[0074] Figure 5is a block diagram of an example UE 500 in accordance with various embodiments of the present disclosure. The UE 500 may be the UE 115 as discussed above. As shown, the UE 500 may include a processor 502, a memory 504, a signal module 505, a grant module 507, a feedback module 509, a transceiver 510 (including a modem subsystem 512 and a radio frequency (RF) unit 514), and one or more antennas 516. These components may communicate directly or indirectly with each other, for example, via one or more buses.

[0075] The processor 502 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 502 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0076] The memory 504 may include cache memory (e.g., cache memory of the processor 502), random access memory (RAM), magnetoresistive RAM (MRAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory devices, hard disk drives, other forms of volatile and nonvolatile memory, or a combination of different types of memory. In one embodiment, the memory 504 includes non-transitory computer readable media. The memory 504 may store instructions 506. The instructions 506 may include instructions that, when executed by the processor 502, cause the processor 502 to perform the operations described herein with reference to the UE 115 in connection with various embodiments of the present disclosure. The instructions 506 may also be referred to as code. The terms "instructions" and "code" should be construed broadly to include any type of computer readable statement. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer readable statement or many computer readable statements.

[0077] Each of the signal module 505, the grant module 507, and the feedback module 509 may be implemented via hardware, software, or a combination thereof. For example, each of the signal module 505, the grant module 507, and the feedback module 509 may be implemented as a processor, a circuit, and / or instructions 506 stored in the memory 504 and executed by the processor 502. Each of the signal module 505, the grant module 507, and the feedback module 509 may be used for various aspects of the present disclosure.

[0078] The signal module 505 can be configured to communicate a first communication signal with a wireless communication device. The first communication signal can be a PDSCH carrying DL data associated with a DL grant. In one example, the signal module 505 receives the first communication signal from the BS105. Referring back Figure 2 , the DL data signal 224 received via the PDSCH can correspond to the first communication signal.

[0079] The grant module 507 can be configured to communicate a grant for retransmitting feedback associated with the first communication signal with a wireless communication device. In one example, the grant module 507 receives DCI indicating a grant for retransmitting the feedback. The grant module 507 may have received a previous grant for transmitting feedback associated with the first communication signal. Due to a missed feedback opportunity, the feedback module 509 may have been unable to transmit the feedback based on the previous grant.

[0080] Referring back Figure 2 , the DCI 240 can indicate a grant for retransmitting the ACK / NACK signal 228, and the ACK / NACK signal 228 indicates feedback for the DL data signal 224. The DCI 240 can also indicate a DL grant for the DL data signal 244 in the time slot 214 with index S0 and a new feedback grant for the DL data signal 244 in the time slot 214 with index S4. Accordingly, the grant for triggering the retransmission of the ACK / NACK signal 228 can be combined with the new feedback grant associated with the DL data signal 244.

[0081] The feedback module 509 can be configured to communicate feedback with a wireless communication device based on the grant. In one example, the feedback module 508 can perform LBT, and if the LBT results in an LBT pass, the feedback module 508 can transmit feedback to the BS105 based on the grant. Referring back Figure 2 , the ACK / NACK signal 228 in the time slot 214 with index S3 can correspond to feedback based on the grant indicated in the DCI 240. The feedback can be an ACK indicating that the UE 115 has successfully received the DL data or a NACK indicating that the UE115 has not successfully received the DL data.

[0082] As shown, transceiver 510 may include a modem subsystem 512 and an RF unit 514. Transceiver 510 may be configured to communicate bidirectionally with other devices (such as BS105 and / or another core network element). Modem subsystem 512 may be configured to modulate and / or encode data from memory 504, signal module 505, grant module 507, and / or feedback module 509 according to a modulation and coding scheme (MCS) (e.g., low-density parity-check (LDPC) coding scheme, turbo coding scheme, convolutional coding scheme, digital beamforming scheme, etc.). RF unit 514 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data of a transmission from modem subsystem 512 (on an outbound transmission) or from another source (such as a UE or BS105). RF unit 514 may be further configured to perform analog beamforming in combination with digital beamforming. Although shown as being integrated together in transceiver 510, modem subsystem 512 and RF unit 514 may be separate devices that are coupled together at UE 500 to enable UE 500 to communicate with other devices.

[0083] RF unit 514 may provide the modulated and / or processed data (e.g., data packets (or more generally, data messages that may include one or more data packets and other information)) to antenna 516 for transmission to one or more other devices. Antenna 516 may further receive data messages transmitted from other devices. Antenna 516 may provide the received data messages for processing and / or demodulation at transceiver 510. Antenna 516 may include multiple antennas of similar or different designs in order to maintain multiple transmission links. RF unit 514 may configure antenna 516.

[0084] Figure 6 is a block diagram of an example BS 600 according to embodiments of the present disclosure. BS 600 may be BS105 as discussed above. As shown, BS 600 may include a processor 602, a memory 604, a signal module 605, a grant module 607, a feedback module 609, a transceiver 610 (including a modem subsystem 612 and an RF unit 614), and one or more antennas 616. These elements may communicate directly or indirectly with each other, for example, via one or more buses.

[0085] Processor 602 may have various features as a dedicated type of processor. For example, these features may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. Processor 602 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0086] Memory 604 may include cache memory (e.g., the cache memory of processor 602), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, a memristor-based array, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some embodiments, memory 604 may include non-transitory computer-readable media. Memory 604 may store instructions 606. Instructions 606 may include instructions that, when executed by processor 602, cause processor 602 to perform the operations described herein. Instructions 606 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statement as discussed above with reference to Figure 5 what was discussed.

[0087] Each of signal module 605, grant module 607, and feedback module 609 may be implemented via hardware, software, or a combination thereof. For example, each of signal module 605, grant module 607, and feedback module 609 may be implemented as a processor, circuitry, and / or instructions 606 stored in memory 604 and executed by processor 602. Each of signal module 605, grant module 607, and feedback module 609 may be used for various aspects of the present disclosure.

[0088] Signal module 605 may be configured to communicate a first communication signal with a wireless communication device. The first communication signal may be a PDSCH carrying DL data associated with a DL grant. In one example, signal module 505 transmits the first communication signal to UE 115. Referring back Figure 2 , the DL data signal 224 transmitted via the PDSCH may correspond to the first communication signal.

[0089] Grant module 607 may be configured to communicate a grant for retransmitting feedback associated with the first communication signal with a wireless communication device. In one example, grant module 607 transmits DCI indicating the grant for retransmitting the feedback. Referring back Figure 2, DCI 240 may indicate a grant for retransmitting the ACK / NACK signal 228, and the ACK / NACK signal 228 indicates feedback for the DL data signal 224. DCI 240 may also indicate a new feedback grant for a new DL data signal 244 (e.g., PDSCH signal).

[0090] In one example, the grant module 607 may detect a missed feedback opportunity. In response to detecting a missed feedback opportunity, the grant module 607 may transmit a retransmission feedback grant (e.g., a grant for retransmitting feedback associated with a first communication signal).

[0091] The feedback module 609 may be configured to communicate feedback with a wireless communication device based on the grant. In one example, the feedback module 609 may receive feedback from the UE 115 based on the grant. Referring back Figure 2 , the ACK / NACK signal 228 in the time slot 214 with index S3 may correspond to feedback based on the grant indicated in the DCI 240. The feedback may be an ACK indicating that the UE 115 has successfully received the DL data or a NACK indicating that the UE 115 has not successfully received the DL data.

[0092] As shown, the transceiver 610 may include a modem subsystem 612 and an RF unit 614. The transceiver 610 may be configured to communicate bidirectionally with other devices (such as the UE 115 and / or another core network element). The modem subsystem 612 may be configured to modulate and / or encode data according to an MCS (e.g., LDPC coding scheme, turbo coding scheme, convolutional coding scheme, digital beamforming scheme, etc.). The RF unit 614 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data of the transmission from the modem subsystem 612 (on an outward transmission) or originating from another source (such as the UE 115 or another BS). The RF unit 614 may be further configured to perform analog beamforming in combination with digital beamforming. Although shown as being integrated together in the transceiver 610, the modem subsystem 612 and / or the RF unit 614 may be separate devices that are coupled together at the BS 600 to enable the BS 600 to communicate with other devices.

[0093] The RF unit 614 may provide modulated and / or processed data (e.g., data packets (or more generally, data messages that may include one or more data packets and other information)) to the antenna 616 for transmission to one or more other devices. This may include, for example, the transmission of information for completing attachment to the network and communication with the serving UE 115 or 500 in accordance with embodiments of the present disclosure. The antenna 616 may further receive data messages transmitted from other devices and provide the received data messages for processing and / or demodulation at the transceiver 610. The antenna 616 may include multiple antennas of similar or different designs to maintain multiple transmission links.

[0094] Figure 7 is a flowchart of a method 700 for conveying a grant for retransmission feedback according to some embodiments of the present disclosure. The steps of method 700 may be performed by a computing device (e.g., a processor, processing circuitry, and / or other suitable components) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device (such as UE 115 or UE 500) may utilize one or more components (such as processor 502, memory 504, signal module 505, grant module 507, feedback module 509, transceiver 510, modem 512, and / or one or more antennas 516) to perform the steps of method 700. In another example, a wireless communication device (such as BS105 or BS 600) may utilize one or more components (such as processor 602, memory 604, signal module 605, grant module 607, feedback module 609, transceiver 610, modem 612, and / or one or more antennas 616) to perform the steps of method 700. Method 700 may employ mechanisms similar to those in communication schemes 200, 300, and 400 described respectively with respect to Figure 2 , 3 and 4. As illustrated, method 700 includes several enumerated steps, but embodiments of method 700 may include additional steps before, after, and between these enumerated steps. In some embodiments, one or more of these enumerated steps may be omitted or performed in a different order.

[0095] In step 710, method 700 includes communicating a first communication signal with a wireless communication device. In one example, the first communication signal is transmitted via the PDSCH. In step 720, method 700 includes communicating a grant for retransmission of feedback associated with the first communication signal with the wireless communication device. In step 730, method 700 includes communicating feedback with the wireless communication device based on the grant.

[0096] In some examples, a first wireless communication device may communicate a second grant to a second communication device for transmitting feedback associated with a first communication signal. The second grant may be communicated before a first grant for retransmitting the feedback. The first wireless communication device may communicate DCI indicating the second grant to the second communication device. Additionally, the first wireless communication device may perform LBT in an unlicensed spectrum to communicate the feedback based on the second grant. The LBT may result in an LBT failure. Accordingly, the first wireless communication device may be unable to communicate the feedback based on the second grant (e.g., due to missing a feedback opportunity). The first wireless communication device may use a first beam to perform LBT for communicating the feedback. In one example, the first wireless communication device communicates the feedback based on the first grant using a second beam different from the first beam. In this example and with reference to Figure 3 , the first wireless communication device may use different beams (e.g., transmission beams 311a and 311b respectively) to communicate PUCCH 316a and PUCCH 316b. In another example, the first wireless communication device communicates the feedback based on the first grant using the first beam. In this example and with reference to Figure 3 , the first wireless communication device may use the same beam (e.g., transmission beam 311a) to communicate PUCCH 316a and PUCCH 316b.

[0097] In some examples, a first wireless communication device may communicate a second communication signal to a second wireless communication device. A grant for retransmitting feedback for the first communication signal may also be used to transmit second feedback associated with the second communication signal. The first wireless communication device may communicate the second feedback to the second wireless communication device based on the grant. In one example, the first wireless communication device may communicate first feedback in a first time slot and second feedback in a second time slot during a first TXOP. The first time slot and the second time slot correspond to the same time slot or different time slots. Additionally, the first and second time slots may be configured by two different Acknowledgment Resource Indicators (ARIs) respectively. In one example, the wireless communication device may communicate the grant by: communicating a first Acknowledgment Resource Indicator (ARI) indicating a first resource for the first feedback in the first time slot and communicating a second ARI indicating a second resource for the second feedback in the second time slot. The first resource and the second resource may be UL resources.

[0098] In one example, the first wireless communication device may use a first beam to communicate the first feedback and a second beam different from the first beam to communicate the second feedback. In another example, the first wireless communication device may use the same beam to communicate the first and second feedback.

[0099] Information and signals can be represented using any of a variety of different arts and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0100] The various illustrative blocks and modules described in connection with the disclosure herein can be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The 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 such configuration).

[0101] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations fall within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the above functions can be implemented using software, hardware, firmware, hardwiring, or any combination thereof executed by a processor. The features implementing the functions can also be physically located in various positions, including being distributed such that portions of the functions are implemented at different physical locations. Additionally, as used herein (including in the claims), the "or" used in a list of items (e.g., a list of items accompanied by phrases such as "at least one of" or "one or more of") indicates an inclusive listing such that, for example, the listing 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).

[0102] As will be appreciated by one of ordinary skill in the art hereto and depending on the particular application at hand, many modifications, substitutions, and variations can be made in the materials, devices, configurations, and methods of use of the devices of the present disclosure without departing from the spirit and scope of the present disclosure. In view of this, the scope of the present disclosure should not be limited to the specific embodiments described and illustrated herein (as they are merely examples of the present disclosure), but should be commensurate with the appended claims and their functional equivalents in their full scope.

Claims

1. A method for wireless communication, comprising: A first wireless communication device conveys a downlink control information DCI message to a second wireless communication device, the DCI message scheduling a first communication signal and including a second grant for transmitting a first feedback associated with the first communication signal; The first wireless communication device conveys a first grant for transmitting the first feedback associated with the first communication signal to the second wireless communication device, the second grant being conveyed before the first grant for transmitting the first feedback; And The first wireless communication device conveys the first feedback to the second wireless communication device based on the first grant.

2. The method according to claim 1, wherein the first communication signal is conveyed via a physical downlink DL shared channel PDSCH.

3. The method according to claim 1, further comprising: The first wireless communication device performs listen-before-talk LBT in an unlicensed spectrum for conveying the first feedback based on the second grant, wherein the LBT results in an LBT failure.

4. The method according to claim 3, wherein performing the LBT includes performing the LBT using a first beam for conveying the first feedback, and wherein conveying the first feedback based on the first grant includes conveying the first feedback using the first beam or using a second beam different from the first beam.

5. The method according to claim 1, further comprising: The first wireless communication device and the second wireless communication device convey a second communication signal, wherein conveying the first grant further includes conveying the first grant for transmitting a second feedback associated with the second communication signal.

6. The method according to claim 5, further comprising: The first wireless communication device conveys the second feedback to the second wireless communication device based on the first grant.

7. The method according to claim 6, wherein conveying the first feedback and the second feedback includes conveying the first feedback in a first time slot and conveying the second feedback in a second time slot during a first transmission opportunity TXOP.

8. The method according to claim 7, wherein the first time slot and the second time slot correspond to the same time slot or different time slots.

9. The method according to claim 7, wherein conveying the first grant further includes: Conveying a first acknowledgement resource indicator ARI indicating a first resource for the first feedback in the first time slot; And Conveying a second ARI indicating a second resource for the second feedback in the second time slot.

10. The method according to claim 6, wherein conveying the first feedback and the second feedback includes conveying the first feedback using a first beam and conveying the second feedback using a second beam different from the first beam.

11. The method according to claim 6, wherein conveying the first feedback and the second feedback includes conveying the first feedback and the second feedback using the same beam.

12. The method according to claim 1, wherein the first grant includes a request for the payload size of the first feedback and further includes a request for a bitmask of one or more DL grants associated with the first feedback.

13. An apparatus for wireless communication, comprising: means for communicating a downlink control information DCI message with a second wireless communication device, the DCI message scheduling a first communication signal and including a second grant for transmitting a first feedback associated with the first communication signal; means for communicating a first grant for transmitting the first feedback associated with the first communication signal with the second wireless communication device, the second grant being communicated before the first grant for transmitting the first feedback; and means for communicating the first feedback with the second wireless communication device based on the first grant.

14. The apparatus according to claim 13, wherein the first feedback includes an acknowledgement ACK indicating error - free reception of the first communication signal or a negative acknowledgement NACK indicating erroneously received first communication signal.

15. The apparatus according to claim 13, wherein the first communication signal is communicated via a physical downlink shared channel PDSCH.

16. The apparatus according to claim 13, further comprising: means for performing listen - before - talk LBT in an unlicensed spectrum for communicating the first feedback based on the second grant, wherein the LBT results in an LBT failure.

17. The apparatus according to claim 16, further comprising: means for performing the LBT using a first beam; and means for communicating the first feedback based on the first grant using a second beam different from the first beam.

18. The apparatus according to claim 16, further comprising: means for performing the LBT using a first beam; and means for communicating the first feedback based on the first grant using the first beam.

19. The apparatus according to claim 13, wherein the first grant includes at least one of: a request for the payload size of the first feedback, or a request for a bitmask of one or more DL grants associated with the first feedback.

20. The apparatus according to claim 13, further comprising: means for communicating a second communication signal with the second wireless communication device; means for communicating a second feedback with the second wireless communication device based on the first grant; and means for communicating the first grant for transmitting the second feedback associated with the second communication signal.

21. The apparatus according to claim 20, further comprising: means for communicating the first feedback in a first time slot and the second feedback in a second time slot during a first transmission opportunity TXOP.

22. The apparatus according to claim 21, wherein the first time slot and the second time slot correspond to the same time slot or different time slots.

23. The apparatus according to claim 20, further comprising: Apparatus for using a first beam to convey the first feedback; and Apparatus for using a second beam different from the first beam to convey the second feedback.

24. The apparatus according to claim 20, further comprising: Apparatus for using the same beam to convey the first feedback and the second feedback.

25. A computer-readable medium having program code recorded thereon, wherein the program code is executable by a processor of a first wireless communication device to cause the first wireless communication device to perform the following operations: Communicate a downlink control information DCI message with a second wireless communication device, the DCI message scheduling a first communication signal and including a second grant for transmitting a first feedback associated with the first communication signal; Communicate a first grant for transmitting the first feedback associated with the first communication signal with the second wireless communication device, the second grant being communicated before the first grant for transmitting the first feedback; and Communicate the first feedback with the second wireless communication device based on the first grant.

26. The computer-readable medium according to claim 25, wherein the program code is further executable by the processor to cause the first wireless communication device to perform the following operations: Perform listen-before-talk LBT using a first beam for conveying the first feedback, wherein the program code being executable by the processor to cause the first wireless communication device to convey the first feedback based on the first grant includes the program code being executable by the processor to cause the first wireless communication device to use the first beam or a second beam different from the first beam to convey the first feedback.

27. The computer-readable medium according to claim 25, wherein the program code being executable by the processor to cause the first wireless communication device to convey the first grant can be further executable by the processor to cause the first wireless communication device to perform the following operations: Convey a first acknowledgement resource indicator ARI indicating a first resource for the first feedback in a first time slot; and Convey a second ARI indicating a second resource for a second feedback associated with a second communication signal in a second time slot.

28. The computer-readable medium according to claim 25, wherein the program code is further executable by the processor to cause the first wireless communication device to perform the following operations: Communicate a second communication signal with the second wireless communication device, wherein the program code being executable by the processor to cause the first wireless communication device to convey the first grant further includes the program code being executable by the processor to cause the first wireless communication device to convey the first grant for transmitting a second feedback associated with the second communication signal; and Communicate the second feedback with the second wireless communication device based on the first grant, The program code can be executed by the processor to cause the first wireless communication device to convey the first feedback and the second feedback, including that the program code can be executed by the processor to cause the first wireless communication device to use the same beam or different beams to convey the first feedback and the second feedback.

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