Apparatus and method for single HARQ-ACK codebook determination

Abstract

Apparatuses and methods for single HARQ-ACK codebook determination are disclosed. The apparatus includes a receiver that receives a first signal configuring a plurality of downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal for HARQ acknowledgement (HARQ-ACK) feedback for each of the plurality of DL HARQ processes and a transmitter that transmits a HARQ-ACK codebook, where the HARQ-ACK codebook includes a first portion including the HARQ-ACK feedback for each of the plurality of DL HARQ processes. The HARQ-ACK codebook can further include a second portion, and each bit in the second portion corresponds to a HARQ process of a number of DL HARQ processes with positive acknowledgements reported for the HARQ process in the first portion.

Description

Technical Field

[0001] The subject matter disclosed herein generally relates to wireless communication, and more specifically to, but not limited to, apparatus and methods for determining a single HARQ-ACK codebook for HARQ-ACK transmission on unlicensed spectrum. Background Technology

[0002] The following abbreviations and acronyms are hereby defined, at least some of which are mentioned in the following description.

[0003] 3rd Generation Partnership Project (“3GPP”), 5th Generation (“5G”), New Radio (“NR”), 5G Node B (“gNB”), Long Term Evolution (“LTE”), LTE-Advanced (“LTE-A”), Evolved UMTS Terrestrial Radio Access Network (“E-UTRAN”), E-UTRAN Node B / Evolved Node B (“eNB”), Universal Mobile Telecommunications System (“UMTS”), Global Microwave Access Interoperability (“WiMAX”), Wireless Local Area Network (“WLAN”), Orthogonal Frequency Division Multiplexing (“OFDM”), Single Carrier Frequency Division Multiple Access (“SC-FDMA”), Downlink (“DL”), Uplink (“UL”), User Entity / Facility (“UE”), Network Facility (“NE”), Millimeter Wave (“mmWave”), Hybrid Automatic Repeat Request (“HARQ”), Positive Acknowledgment (“ACK”), Hybrid Automatic Repeat Request Acknowledgment (“HARQ-ACK”), Radio Access Technology (“RAT”), Negative Acknowledgment (“NACK”), Receive (“RX”), Transmit (“TX”), Downlink Control Information (“DCI”), Physical Downlink Control Channel (“PDCCH”), Very Large Scale Integration (“VLSI”), Frequency Division Multiple Access (“FDMA”), Multiple Input Multiple Output (“MIMO”), Multi-User MIMO (“MU-MIMO”), Physical Uplink Control Channel (“PUCCH”), Channel State Information Reference Signal (“CSI-RS”), Control Resource Set (“CORESET”), Uplink Control Information (“UCI”), Transmit Receive Point (“TRP”), Channel Occupancy Time (“COT”), Code Block Group (“CBG”), Listen Before Talk (“LBT”), Maximum Channel Occupancy Time (“MCOT”), NR Access on Unlicensed Spectrum (“NR-U”), Physical Downlink Shared Channel (“PDSCH”), Physical Uplink Shared Channel (“PUSCH”), Radio Resource Control (“RRC”), Transport Block (“TB”), Transport Block Size (“TBS”), Radio Link Control (“RLC”), Downlink Assignment Index (“DAI”), HARQ Process ID (“HPID”), Automatic Repeat Request (“ARQ”), Carrier Aggregation (“CA”), and Retransmission ACK Indicator (“RAI”).

[0004] In wireless communications such as 3GPP mobile networks, a wireless mobile network can provide seamless wireless communication services to mobile wireless communication terminals, i.e., user facilities (UEs). A wireless mobile network can consist of multiple base stations, and each base station can perform wireless communication with the UE.

[0005] 5G New Radio (NR) is the latest standard in the 3GPP standard family, which supports very high data rates and lower latency compared to its predecessor, LTE (4G) technology.

[0006] In 3GPP 5G NR, downlink (DL) transport blocks (TBs) are carried on the Physical Downlink Shared Channel (PDSCH) from the gNB to the UE. In one example, up to two TBs can be transmitted on the PDSCH within a serving cell and a timeslot. HARQ-ACK (Hybrid Automatic Repeat Request Acknowledgment) is a collective term for positive acknowledgment (ACK) and negative acknowledgment (NACK). ACK indicates that the TB was correctly received by the UE, while NACK indicates that the TB was incorrectly received by the UE.

[0007] For TB-based retransmissions, one HARQ-ACK feedback bit corresponds to one TB. A HARQ-ACK information bit value of 0 indicates NACK, while a HARQ-ACK information bit value of 1 indicates ACK. The HARQ-ACK feedback bit corresponding to the PDSCH is sent from the UE to the gNB on the Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH).

[0008] In NR, in addition to TB-based retransmission, CBG (block group)-based retransmission is also supported. The purpose of a CBG is to group several code blocks into a block group, and as a result, each CBG generates a HARQ-ACK feedback. Only if all code blocks within a CBG are correctly decoded can the HARQ-ACK of that CBG be set to ACK; otherwise, it is set to NACK. Upon receiving a HARQ-ACK feedback, the transmitter at the gNB side will only retransmit the CBG with NACK.

[0009] For CBG-based retransmissions, RRC signaling is used to configure the maximum number of CBGs per TB. The maximum number of CBGs per TB can be 2, 4, 6, or 8. For both semi-static and dynamic HARQ-ACK codebooks, the number of HARQ-ACK bits per TB is equal to the maximum number of CBGs configured per TB, regardless of the variable transport block size (TBS) for a given TB.

[0010] HARQ-ACK feedback from multiple PDSCHs can be multiplexed into a single HARQ-ACK codebook using HARQ-ACK multiplexing. There are two methods for determining the HARQ-ACK codebook for NR version 15:

[0011] The semi-static HARQ-ACK codebook (also known as Type 1 in TS38.213) – the size of the semi-static HARQ-ACK codebook is determined based on the number of TB configurations for a PDSCH, the number of candidate PDSCH timings in the time domain, the number of DL carrier configurations, and the maximum number of CBG configurations per TB. Therefore, semi-static HARQ-ACK codebook determination is more robust to lost and / or erroneous DCI detection than dynamic HARQ-ACK codebook determination. However, this robustness comes at the cost of more bits in the HARQ-ACK feedback.

[0012] The dynamic HARQ-ACK codebook (also known as Type 2 in TS38.213) – the size of the dynamic HARQ-ACK codebook is determined based on the number of DL transmissions to be acknowledged actually received in the same time slot. To address the issue of lost and erroneous DCI detection, a counter downlink assignment index (DAI) and a total DAI field are specified in the DCI. Summary of the Invention

[0013] According to a first aspect, an apparatus is provided, comprising: a receiver that receives a first signal configuring the number of downlink (DL) Hybrid Automatic Repeat Request (HARQ) processes and a second signal triggering HARQ acknowledgment (HARQ-ACK) feedback for each of the plurality of DL HARQ processes; and a transmitter that transmits a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes.

[0014] The HARQ-ACK codebook may further include a second part, and each bit in the second part corresponds to the number of DL HARQ processes that reported a positive response to the HARQ process in the first part.

[0015] According to a second aspect, an apparatus is provided, comprising: a transmitter that transmits a first signal configuring a plurality of downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal triggering HARQ acknowledgment (HARQ-ACK) feedback for each of the plurality of DL HARQ processes; and a receiver that receives a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes.

[0016] According to a third aspect, a method is provided, comprising: receiving a first signal configuring a plurality of downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal triggering HARQ acknowledgment (HARQ-ACK) feedback for each of the plurality of DL HARQ processes; and sending a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes.

[0017] According to a fourth aspect, a method is provided, comprising: sending a first signal configuring a plurality of downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal triggering HARQ acknowledgment (HARQ-ACK) feedback for each of the plurality of DL HARQ processes; and receiving a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes. Attached Figure Description

[0018] A more detailed description of the embodiments will now be provided with reference to the specific embodiments illustrated in the accompanying drawings. Given that these drawings depict only some embodiments and are therefore not to be considered as limiting the scope, these embodiments are described and explained below with additional specificity and detail using the drawings, wherein:

[0019] Figure 1 This is a schematic diagram of a wireless communication system.

[0020] Figure 2 This is a schematic block diagram illustrating an apparatus that can be used for single-shot HARQ-ACK codebook determination according to one embodiment;

[0021] Figure 3 This is a schematic block diagram illustrating an apparatus that can be used for single-shot HARQ-ACK codebook determination according to one embodiment;

[0022] Figure 4A This is a schematic diagram illustrating a single HARQ-ACK feedback according to one embodiment;

[0023] Figure 4B This is a schematic diagram of a single HARQ-ACK feedback according to one embodiment;

[0024] Figure 5 This is a schematic diagram illustrating error handling for a single HARQ-ACK feedback according to one embodiment;

[0025] Figure 6 This is a schematic diagram illustrating error handling for a single HARQ-ACK feedback according to one embodiment;

[0026] Figure 7 This is a flowchart illustrating the steps of determining a single HARQ-ACK codebook according to one embodiment; and

[0027] Figure 8 This is a flowchart illustrating the steps of determining a single HARQ-ACK codebook according to one embodiment. Detailed Implementation

[0028] Those skilled in the art will understand that aspects of the embodiments can be embodied as a system, apparatus, method, or program product. Therefore, embodiments can take the form of an all-hardware embodiment, an all-software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware solutions.

[0029] For example, the disclosed embodiments can be implemented as hardware circuitry, including custom very large-scale integration (VLSI) circuitry or gate arrays, existing semiconductors such as logic chips, transistors, or other discrete components. Furthermore, the disclosed embodiments can be implemented in programmable hardware devices such as field-programmable gate arrays, programmable array logic, programmable logic devices, etc. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code, which may be organized as objects, processes, or functions.

[0030] Furthermore, one or more embodiments may take the form of a program product embodied in one or more computer-readable storage devices that store machine-readable code, computer-readable code, and / or program code, hereinafter referred to as "code". The storage device may be tangible, non-transitory, and / or non-transferable.

[0031] Any combination of one or more computer-readable media may be used. A computer-readable medium may be a computer-readable storage medium. A computer-readable storage medium may be a storage device for storing code. A storage device may be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof.

[0032] A non-exhaustive list of more specific examples of storage devices may include the following: electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (“RAM”), read-only memory (“ROM”), erasable programmable read-only memory (“EPROM” or flash memory), portable optical disc read-only memory (“CD-ROM”), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the context of this invention, a computer-readable storage medium can be any tangible medium capable of containing or storing a program for use by or in connection with an instruction execution system, apparatus, or device.

[0033] References to "one embodiment," "embodiment," "example," "some embodiments," or similar language in this specification mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, the phrases "in one embodiment," "in an embodiment," "in some embodiments," and similar language appearing throughout this specification may, but not necessarily, refer to the same embodiment, but rather to "one or more embodiments." They may include all disclosed embodiments, or may not, exclude them. Unless expressly stated otherwise, the term "comprising" and its variations mean "including, but not limited to, embodiments."

[0034] Unless otherwise expressly stated, the list of items does not imply that any or all items are mutually exclusive. Unless otherwise expressly stated, the terms “a,” “an,” and “the” also mean “one or more.”

[0035] Throughout this disclosure, the terms "first," "second," "third," etc., are used solely for reference to the relevant equipment, components, procedure steps, etc., and do not imply any spatial or temporal order unless explicitly stated otherwise. For example, "first equipment" and "second equipment" can refer to two separately formed devices, or two parts or components of the same device. In some cases, such as, "first equipment" and "second equipment" can be the same and can be arbitrarily named. Similarly, a "first step" of a method or process may be performed or carried out after or simultaneously with a "second step."

[0036] Furthermore, the features, structures, or characteristics of the embodiments can be combined in any suitable manner. In the following description, numerous specific details, such as examples of programming, software modules, user selection, online transactions, database queries, database structures, hardware modules, hardware circuits, and hardware chips, are provided to provide a thorough understanding of the embodiments. However, those skilled in the art will recognize that the embodiments can be practiced without one or more of these specific details or through other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the embodiments.

[0037] Various embodiments are described below with reference to schematic flowcharts and / or schematic block diagrams of methods, apparatus, systems, and program products. It should be understood that each step in the schematic flowcharts and / or schematic block diagrams, as well as combinations of steps in the schematic flowcharts and / or schematic block diagrams, can be implemented by code. This code can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that instructions executable via the processor of the computer or other programmable data processing apparatus can create means for implementing the functions / actions specified in the schematic flowcharts and / or schematic block diagrams.

[0038] In addition, code can be stored in a storage device that can instruct a computer, other programmable data processing device or other device to operate in a particular manner, such that the instructions stored in the storage device can produce an article of art including instructions that implement the functions / actions specified in the schematic flowchart and / or schematic block diagram.

[0039] In addition, code can be loaded onto a computer, other programmable data processing apparatus or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce computer-implemented processing, thereby enabling the code executed on the computer or other programmable apparatus to provide processing for implementing the functions / actions specified in the schematic flowchart and / or schematic block diagram.

[0040] The schematic flowcharts and / or schematic block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of various apparatus, systems, methods, and program products according to various embodiments. In this regard, each step in the schematic flowcharts and / or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing a specified logical function. However, those skilled in the art will recognize that the flowcharts do not need to be practiced in the order shown and can be practiced without one or more specific steps or by means of other steps not shown.

[0041] Furthermore, it should be noted that in some alternative embodiments, the functions mentioned in the identified boxes do not necessarily appear in the order shown in the figures. For example, depending on the functions involved, two consecutively shown steps may actually be performed simultaneously, or sometimes in reverse order. Other steps and methods that are functionally, logically, or effectively equivalent to one or more steps or portions of the steps shown in the figures can be conceived.

[0042] The description of elements in each figure can be referenced to the elements in the preceding figures. In all figures, the same reference numerals denote the same elements, including alternative embodiments of the same elements.

[0043] Figure 1 This is a schematic diagram of a wireless communication system. It depicts an embodiment of a wireless communication system 100 for single-shot HARQ-ACK codebook determination. In one embodiment, the wireless communication system 100 may include a user facility (UE) 102 and a network facility (NE) 104. Although in Figure 1 A specific number of UEs 102 and NEs 104 are depicted in the description, but those skilled in the art will recognize that the wireless communication system 100 may include any number of UEs 102 and NEs 104.

[0044] UE 102 may be referred to as a remote device, remote unit, subscriber unit, mobile station, mobile station, user, terminal, mobile terminal, fixed terminal, subscriber station, user terminal, apparatus, device or other terms used in the art.

[0045] In one embodiment, UE 102 may be an autonomous sensor device, alarm device, actuator device, remote control device, etc. In some other embodiments, UE 102 may include computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smartphones, smart TVs (e.g., internet-connected TVs), set-top boxes, game consoles, security systems (including security cameras), in-vehicle computers, network devices (e.g., routers, switches, modems), etc. In some embodiments, UE 102 includes wearable devices such as smartwatches, fitness trackers, optical head-mounted displays, etc. UE 102 may communicate directly with one or more NEs 104.

[0046] NE 104 may also be referred to as a base station, access point, access terminal, Node-B, eNB, gNB, home Node-B, relay node, apparatus, device, or any other term used in the art. Throughout this specification, references to "base station" may refer to any of the above reference types for network facility 104, such as eNB and gNB.

[0047] NE 104 can be distributed across a geographical area. NE 104 is typically part of a radio access network, which includes one or more controllers communicatively connected to one or more corresponding NE 104. The radio access network is typically communicatively connected to one or more core networks, which can be coupled to other networks such as the Internet and the public switched telephone network. These and other components of the radio access and core networks are not shown, but are well known to those skilled in the art.

[0048] In one implementation, the wireless communication system 100 conforms to 3GPP 5G New Radio (NR). In some implementations, the wireless communication system 100 conforms to 3GPP protocols, wherein NE 104 transmits on DL using an OFDM modulation scheme, while UE 102 transmits on UL using an SC-FDMA scheme or an OFDM scheme. However, more generally, the wireless communication system 100 may implement other open or proprietary communication protocols, such as WiMAX. This disclosure is not intended to limit implementation to any particular wireless communication system architecture or protocol.

[0049] NE 104 can serve multiple UE 102s within the service area of, for example, one cell (or cell sector) or more cells via a wireless communication link. NE 104 transmits DL communication signals to serve UE 102s in the time domain, frequency domain, and / or spatial domain.

[0050] Figure 2 This is a schematic block diagram illustrating an apparatus that can be determined based on a codebook available for a single HARQ-ACK. In one embodiment, the apparatus includes a user facility (UE) 200. UE 200 may include a processor 202, memory 204, an input device 206, a display 208, and a transceiver 210. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touchscreen. In some embodiments, UE 200 may not include any input device 206 and / or display 208. In various embodiments, UE 200 may include one or more processors 202 and may not include the input device 206 and / or display 208.

[0051] In one embodiment, processor 202 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, processor 202 may be a microcontroller, microprocessor, central processing unit (“CPU”), graphics processing unit (“GPU”), auxiliary processing unit, field-programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, processor 202 executes instructions stored in memory 204 to perform the methods and routines described herein. Processor 202 may be communicatively coupled to memory 204 and transceiver 210.

[0052] In one embodiment, memory 204 is a computer-readable storage medium. In some embodiments, memory 204 includes volatile computer storage media. For example, memory 204 may include RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and / or static RAM (“SRAM”). In some embodiments, memory 204 includes non-volatile computer storage media. For example, memory 204 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, memory 204 stores data related to triggering conditions for sending measurement reports to network facilities. In some embodiments, memory 204 also stores program code and related data.

[0053] In one embodiment, input device 206 may include any known computer input device, including a touch panel, buttons, keyboard, stylus, microphone, etc. In some embodiments, input device 206 may be integrated with display 208, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, input device 206 includes a touchscreen, enabling text input using a virtual keyboard displayed on the touchscreen and / or via handwriting on the touchscreen. In some embodiments, input device 206 includes two or more different devices, such as a keyboard and a touch panel.

[0054] In one embodiment, display 208 may include any known electronically controllable display or display device. Display 208 may be designed to output visual, audio, and / or tactile signals. In some embodiments, display 208 includes an electronic display capable of outputting visual data to a user. For example, display 208 may include, but is not limited to, LCD displays, LED displays, OLED displays, projectors, or similar display devices capable of outputting images, text, etc., to a user. As another non-limiting example, display 208 may include wearable displays such as smartwatches, smart glasses, head-up displays, etc. Furthermore, display 208 may be a component of a smartphone, personal digital assistant, television, desktop computer, laptop computer, personal computer, vehicle dashboard, etc.

[0055] In some embodiments, display 208 includes one or more speakers for generating sound. For example, display 208 may generate audio alarms or notifications (e.g., beeps or beeps). In some embodiments, display 208 includes one or more haptic devices for generating vibration, motion, or other haptic feedback. In some embodiments, all or part of display 208 may be integrated with input device 206. For example, input device 206 and display 208 may form a touchscreen or similar touch-sensitive display. In other embodiments, display 208 may be positioned close to input device 206.

[0056] In one embodiment, transceiver 210 is configured to wirelessly communicate with a network facility. In some embodiments, transceiver 210 includes a transmitter 212 and a receiver 214. The transmitter 212 is used to transmit UL communication signals to the network facility, while the receiver 214 is used to receive DL communication signals from the network facility. For example, the transmitter 212 may transmit a HARQ-ACK codebook including one or more DL transmissions. As another example, the receiver 214 may receive various configuration / data from the network facility.

[0057] Transmitter 212 and receiver 214 can be any suitable type of transmitter and receiver. Although only one transmitter 212 and one receiver 214 are shown, transceiver 210 can have any suitable number of transmitters 212 and receivers 214. For example, in some embodiments, UE 200 includes multiple pairs of transmitters 212 and receivers 214 for communication over multiple wireless networks and / or radio frequency bands, each pair of transmitters 212 and receivers 214 being configured to communicate over a different wireless network and / or radio frequency band than another pair of transmitters 212 and receivers 214.

[0058] Figure 3 This is a schematic block diagram illustrating an apparatus that can be used for single-shot HARQ-ACK codebook determination. In one embodiment, the apparatus includes a network facility (NE) 300. The network facility (NE) 300 may be... Figure 1 An exemplary implementation of NE 104.

[0059] NE 300 may include processor 302, memory 304, input device 306, display 308, and transceiver 310. It will be understood that in some embodiments, processor 302, memory 304, input device 306, display 308, and transceiver 310 may be similar to processor 202, memory 204, input device 206, display 208, and transceiver 210 of UE 200, respectively.

[0060] In some embodiments, processor 302 controls transceiver 310 to send DL signals / data to UE 200. Processor 302 can also control transceiver 310 to receive UL signals / data from UE 200. For example, processor 302 can control transceiver 310 to receive a HARQ-ACK codebook including one or more DL transmissions. In another example, processor 302 can control transceiver 310 to send DL signals for various configurations to UE 200, as described above.

[0061] In one embodiment, transceiver 310 is configured to communicate wirelessly with UE 200. In some embodiments, transceiver 310 includes a transmitter 312 and a receiver 314. Transmitter 312 is used to transmit DL communication signals to UE 200, while receiver 314 is used to receive UL communication signals from UE 200. For example, receiver 314 can receive a HARQ-ACK codebook from UE 200. As another example, transmitter 312 can transmit various configurations / data of NE 300.

[0062] Transceiver 310 can communicate with multiple UEs 200 simultaneously. For example, transmitter 312 can send DL communication signals to UE 200. As another example, receiver 314 can simultaneously receive UL communication signals from UE 200. Transmitter 312 and receiver 314 can be any suitable type of transmitter and receiver. Although only one transmitter 312 and one receiver 314 are shown, transceiver 310 can have any suitable number of transmitters 312 and receivers 314. For example, NE 300 can serve multiple cells and / or cell sectors, where transceiver 310 includes transmitters 312 and / or receivers 314 for each cell or cell sector.

[0063] For transmissions on unlicensed spectrum (NR-U), a channel access procedure, also known as LBT (Listen-Before-Tell), is required before transmission can proceed to ensure fair coexistence with other wireless systems. This involves performing an energy check on a channel. If the received power is below a predefined threshold, the LBT succeeds, meaning the channel is considered idle and available for transmission. If the received power is above the threshold, the LBT fails, meaning the channel is occupied by another node or other wireless system and is unavailable for transmission. Only when the LBT succeeds can a facility begin transmitting on the channel and occupy it until the Maximum Channel Occupancy Time (MCOT). Otherwise, the facility cannot initiate transmission and continues executing the LBT until successful.

[0064] When sending HARQ-ACK feedback on an unlicensed carrier, LBT (Local Level Bypass) is required before HARQ-ACK transmission. The UE can begin HARQ-ACK transmission if and only if LBT succeeds; otherwise, the UE must abandon HARQ-ACK transmission. If the UE fails to send HARQ-ACK feedback due to LBT failure, the gNB must retransmit the corresponding PDSCH because it does not know the UE's decoding result for the PDSCH.

[0065] Furthermore, HARQ-ACK transmissions on unlicensed carriers experience potential interference from hidden nodes. Even if the UE has successfully sent HARQ-ACK feedback, there is still a possibility that the gNB may fail to decode it. At the gNB side, if the gNB fails to detect HARQ-ACK feedback within the predefined HARQ-ACK feedback timing, the gNB will have to assume NACK and retransmit all corresponding PDSCHs. Due to HARQ-ACK reception failures at the gNB side, LBT failures and hidden node issues can both lead to unnecessary DL retransmissions and DL performance degradation.

[0066] For NR access on unlicensed spectrum (NR-U), a single HARQ-ACK feedback is discussed as a fallback solution for both semi-static and dynamic HARQ-ACK codebooks. Specifically, as soon as the UE receives the trigger DCI, it should send HARQ-ACK bits for all configured downlink (DL) HARQ processes. This triggers not only delayed HARQ-ACK feedback for the PDSCH in the earlier Channel Occupied Time (COT), but also previously sent HARQ-ACK feedback for transmission. This mechanism applies to both semi-static and dynamic HARQ-ACK codebooks.

[0067] A single HARQ-ACK feedback can result in a large HARQ-ACK codebook, even much larger than a semi-static HARQ-ACK codebook. For example, the typical number of DL HARQ processes is 16, so the single HARQ-ACK codebook size is equal to 16 for single-codeword transmission mode or 32 for double-codeword transmission mode. The advantage of single HARQ-ACK feedback is that determining the codebook size is very simple. Even with some DL transmission losses, there is no ambiguity between the UE and gNB in ​​determining the HARQ-ACK codebook size.

[0068] For a single HARQ-ACK feedback, when the UE has already reported an ACK for a given HARQ process and missed a new DL assignment for a given HARQ process, a misunderstanding occurs between the gNB and the UE regarding the HARQ-ACK codebook. Figure 4A The diagram shows an example of a single HARQ-ACK feedback that illustrates a misunderstanding.

[0069] exist Figure 4A In this example, a semi-static HARQ-ACK codebook is configured for the UE. In practice, the UE can also be configured with a dynamic HARQ-ACK codebook. For simplicity, assume that set K1 includes {1,2,3,4}, and for the PDSCH in slots n, n+1, n+2, and n+3, the corresponding HARQ process IDs are x, x+1, x+2, and x+3, respectively. Therefore, without considering carrier aggregation (CA), block group (CBG), and multiple-input multiple-output (MIMO), the four HARQ-ACK information bits a corresponding to the PDSCH in slots n, n+1, n+2, and n+3... x a x+1 a x+2 and a x+3 It is generated as a semi-static HARQ-ACK codebook and transmitted in time slot n+4.

[0070] Assume the gNB sends a DCI in time slot m to schedule the DL transmission of HARQ process x, and sends a single-trigger DCI in time slot m+2 to trigger the UE to report HARQ-ACK feedback for all 16 configured HARQ processes in time slot m+3. At the UE side, after receiving the single-trigger DCI, the UE should generate b0, b1, b2, ..., b15 as a single-trigger HARQ-ACK codebook for the 16 HARQ processes in order of HARQ process ID. When the UE misses or does not receive the DCI in time slot m used to schedule HARQ process x, the UE is unaware that HARQ process x has been rescheduled for the new transmission. Therefore, the UE will use the latest HARQ-ACK information bits for HARQ process x, a x The PDSCH reused in slot n serves as the HARQ-ACK information bit for HARQ process x in a single HARQ-ACK codebook, b x If a x If it is the ACK in the earlier type 1 (semi-static HARD-ACK) codebook, then b x For a x The ACK is reused and reported to the gNB in ​​a single HARD-ACK codebook. In this case, the gNB assumes that the TB sent by the HARQ process x scheduled in slot m was successfully received by the UE and therefore will not retransmit it. However, the UE actually misses the DL transmission. From the physical layer's perspective, the UE loses (or misses) the TB unless Radio Link Control (RLC) Automatic Repeat Request (ARQ) is initiated.

[0071] A similar problem occurs when a DCI for a given HARQ process is lost between two consecutive single-trigger DCIs, such as... Figure 4B As shown. In Figure 4B In this context, gNB assumes that the TB transmitted by HARQ process x, scheduled in slot m between two single-triggered DCIs, is successfully received by the UE and therefore will not be retransmitted. However, the UE actually misses this DL transmission.

[0072] Note that in Figure 4A and Figure 4B In both cases, a PDSCH carries only one TB, and each TB is acknowledged with one bit of ACK or NACK. When at most two TBs are configured for a PDSCH or when CBG-based retransmission is configured for the PDSCH, each HARQ process will use C*M bits for acknowledgment, where C is the number of TBs configured for a PDSCH, and M is the maximum number of RRC configurations for each TB CBG. As a result, a single HARQ-ACK codebook comprises N*C*M bits, where N is the number of configured DL HARQ processes.

[0073] To address this error situation, several methods can be used. The first approach is to indicate the NDI for each HARQ process in the triggering DCI. However, this impacts the DCI design. Clearly, this is unsuitable for using DL assignment or UL permission as the triggering DCI. The second approach is to indicate the NDI for each HARQ process in the single HARQ-ACK codebook. The drawback is the excessive overhead, which increases exponentially. The third approach is to always assume NACK for HARQ processes that have already been reported. The problem with this method is that HARQ-ACK retransmission opportunities are lost.

[0074] This disclosure provides apparatus and methods for determining a single HARQ-ACK codebook for NR access on unlicensed spectrum (NR-U), and discloses several methods for handling the aforementioned error conditions.

[0075] According to some embodiments, a single HARQ-ACK codebook comprises two parts: a first part, which includes HARQ-ACK information bits for each HARQ process, concatenated in order of HARQ process ID; and a second part, in which each bit corresponds to one of the HARQ processes that reported a positive response to a HARQ process in the first part.

[0076] In some embodiments, the second part of a single HARQ-ACK codebook includes X retransmission ACK indication (RAI) bits.

[0077] The total size of a single HARQ-ACK codebook is equal to N*C*M+X, where N is the number of configured DL HARQ processes, C is the maximum number of TB-based RRC configurations that can be carried on a single PDSCH, and M is the maximum number of CBG-based RRC configurations per TB. When spatial clustering is used or only one TB can be carried on a single PDSCH, C equals 1. When no CBG-based retransmission is configured, M equals 1.

[0078] RAI is used to indicate whether the information bits of the ACK for a given HARQ process are retransmitted within a single HARQ-ACK codebook or sent initially. Because RAI is introduced to address the error situation of DCI loss for scheduling one or two TBs or multiple CBGs for a given HARQ process, one RAI bit corresponds to a given HARQ process. Therefore, the number of RAI bits in the second part is no greater than the number of configured DL HARQ processes. For simplicity, in the following example, it is assumed that a PDSCH can only carry one TB and no CBG-based retransmission is configured. Such a configuration is for illustrative purposes only, and this disclosure is not intended to be limited thereto.

[0079] like Figure 5 As shown, when the UE reports an ACK in time slot n+4 of HARQ process x and misses the DL assignment for scheduling HARQ process x in time slot m, the UE retransmits a in a single HARQ-ACK codebook. x (That is, the ACK for PDSCH in slot n), as b in the first part x And in the second part, the RAI is indicated as "1" for the HARQ process x. Here, a RAI of "1" indicates that the corresponding ACK is in an earlier HARQ-ACK codebook (e.g., Figure 5 The ACK is reported in the Type 1 HARQ-ACK codebook and retransmitted in the current single-pass HARQ-ACK codebook; and RAI of "0" indicates that the corresponding ACK was newly generated for the given HARQ process x after the previous HARQ-ACK report and was initially sent in the current single-pass HARQ-ACK codebook. That is, RAI of "1" means that the same ACK bit is reported for the same PDSCH for the given HARQ process, that is, there is no new DL schedule for the given HARQ process detected by the UE between the previous HARQ-ACK report and the current single-pass DCI trigger. RAI of "0" means different ACK bits for different PDSCHs for the given HARQ process, that is, there is a new DL schedule for the given HARQ process that is correctly decoded by the UE between the previous HARQ-ACK report and the current single-pass DCI trigger.

[0080] In the example, assume that the HARQ-ACK information bits for HARQ processes x and x+1 in time slots n and n+1 are ACK, that is, a x =ACK and a x+1 =ACK, and the DCI in slot m of scheduled HARQ process x is missed by the UE, and the DCI in slot m+1 of scheduled HARQ process x+1 is detected and the UE correctly decodes the associated PDSCH. Therefore, in a single HARQ-ACK codebook, b x =ACK and b x+1 =ACK, where b x =ACK is the ACK retransmission of PDSCH in slot n, and b x+1 =ACK is the initial transmission of the ACK for PDSCH in time slot m+1. To distinguish whether the same ACK or a different ACK is reported for HARQ process x or x+1 in the current single HARQ-ACK codebook compared with the previous HARQ-ACK codebook, in the second part, the RAI of HARQ process x is set to "1", which means that this ACK is a retransmission of an earlier ACK, and the RAI of HARQ process x+1 is set to "0", which means that this ACK is a new ACK that is different from the corresponding earlier ACK in the previous HARQ-ACK codebook.

[0081] In this way, after receiving the current single HARQ-ACK codebook at the gNB side, the gNB can know that the UE missed the DCI in time slot m because the reported RAI is "1", and will retransmit the data in the next time slot (scheduled by the missed DCI).

[0082] Since a RAI bit indicates or represents a retransmission ACK or an initial ACK for a given HARQ process, a mapping relationship is established between the RAI bit and the corresponding HARQ process.

[0083] In one embodiment, X is set to the number of configured DL HARQ processes. Here, each of the X RAI bits in the second part of the single HARQ-ACK codebook corresponds to one of the configured DL HARQ processes. Therefore, the aforementioned error condition can be eliminated, but the disadvantage is the higher signaling overhead when configuring 16 DL HARQ processes.

[0084] In one embodiment, X is set to a fixed value according to a standard or a fixed value configured by Radio Resource Control (RRC) signaling. For example, X is set to 2, 4, 8, or other values. The gNB can configure an appropriate value for X based on the statistical probability of error conditions occurring, where X is less than the configured number of DL HARQ processes. The following options can be used.

[0085] Option 1: The X RAI bits in the second part correspond to the first X HARQ processes of a subset S of N configured HARQ processes, where each HARQ process in subset S or each of the S HARQ processes has reported an ACK in the previous HARQ-ACK codebook and the current single HARQ-ACK codebook.

[0086] like Figure 5 As shown, for HARQ process x, if a x =ACK and b x =NACK, then HARQ process x is not included in the S HARQ processes; if a x =NACK and b x =ACK, then HARQ process x is also not included in the S HARQ processes; and only a x =ACK and b x When =ACK is received, HARQ process x is included in the S HARQ processes.

[0087] Here, the second part only includes the corresponding RAI bits for the first X processes of the S HARQ processes. By comparing the two HARQ-ACK codebooks (the previous HARQ-ACK codebook and the current HARQ-ACK codebook), the gNB can determine which HARQ process the reported RAI bit corresponds to. If S > X, then the last X HARQ processes of the S HARQ processes do not report corresponding RAI bits. If S = 0, then the second part is padded with X "NACK" bits or "ACK" bits.

[0088] For example, for HARQ processes x, x+1, x+2, and x+3, (ACK, ACK, NACK, ACK) are reported in time slot n+4. The UE loses the DCI in time slot m and detects the DCI in time slot m+1 and correctly decodes the PDSCH scheduled by the DCI in time slot m+1. Assuming X=4 and S=2, the UE then reports ACK, reporting ACK for HARQ processes x and x+1 in the first part of the single HARQ-ACK codebook, and indicating 4 RAI bits (X=4) as 1, 0, 0, 0 in the second part, where "1" indicates that the ACK for HARQ process x is retransmitted, the first "0" indicates that the ACK for HARQ process x+1 is newly generated and initially sent, and the last two "0"s are padding bits. Assuming X=4 and S=6, the UE reports 4 RAI bits, "1, 0, 0, 0", which correspond to the first 4 of the 6 HARQ processes. The "1" indicates that the ACK for HARQ process x is retransmitted, the first "0" indicates that the ACK for HARQ process x+1 is regenerated and initially sent, and the last two "0" indicate the RAI bits for the third and fourth HARQ processes.

[0089] If the first HARQ-ACK codebook (or the previous HARQ-ACK codebook) is not correctly received by the gNB due to hidden node interference, or if the previous HARQ-ACK codebook is not sent by the UE due to LBT failure, then the gNB does not need to schedule DL transmissions on HARQ processes x, x+1, x+2, and x+3. In this case, after sending a single triggered DCI, the gNB checks the first part of the single HARQ-ACK codebook and ignores the second part.

[0090] Option 2: The X RAI bits in the second part correspond to the last X HARQ processes of a subset S of N configured HARQ processes, where each of the S HARQ processes in the previous HARQ-ACK codebook and in the current single HARQ-ACK codebook is reported with an ACK. The details for determining the S HARQ processes and RAI bits are similar to those in Option 1.

[0091] In one embodiment, X is dynamically indicated during the triggering of the DCI. By dynamically indicating X during the triggering of the DCI, the gNB can adaptively adjust the value of X based on the number of ACK bits received in the previous HARQ-ACK codebook.

[0092] For example, suppose there are Z1 HARQ processes reported with ACK in the previous HARQ-ACK codebook, and the gNB schedules Z2 HARQ processes from the previous Z1 HARQ processes between the previous HARQ-ACK codebook and the current triggering DCI with the switched NDI for new data transmission. Theoretically, when all Z2 HARQ processes are correctly decoded by the UE and acknowledged with ACK, at most Z2 HARQ processes require RAI bits in the second part of a single HARQ-ACK codebook. In this case, setting the value of X to Z2 in the triggering DCI can resolve the error situation.

[0093] like Figure 5 As shown in the figure, assuming 4 HARQ-ACK information bits a x a x+1 a x+2 a x+3 If the result is (ACK, ACK, NACK, ACK), then there are three HARQ processes reported as ACK in the Type 1 HARQ-ACK codebook: HARQ processes x, x+1, and x+3. Further assuming that HARQ processes x and x+1 are scheduled for new data transmission in time slots m and m+1 respectively, meaning there are two of the aforementioned three HARQ processes scheduled between the Type 1 HARQ-ACK report and the single-trigger DCI, then at most two HARQ processes can be reported as ACK in both the Type 1 HARQ-ACK codebook and the single-trigger HARQ-ACK codebook: HARQ processes x and x+1. In this case, the gNB can indicate the value of X as 2 in the trigger DCI, where 2 RAI bits are sufficient to avoid error conditions.

[0094] Upon receiving the trigger DCI, the UE can set the value of X to 2 and generate 2 RAI bits in the second part of the single HARQ-ACK codebook corresponding to HARQ processes x and x+1.

[0095] The number of bits used to indicate X in triggering DCI is equal to ceil(log2(N)), where N is the number of configured DL HARQ processes. When 16 DL HARQ processes are configured, in extreme cases, 4 bits are required in both the previous HARQ-ACK codebook and the single HARQ-ACK codebook to indicate the maximum of 16 HARQ processes that have reported ACKs.

[0096] In some cases, if the first HARQ-ACK codebook or a previous HARQ-ACK codebook is not correctly received by the gNB due to hidden node interference, or is not transmitted by the UE due to LBT failure, the gNB will indicate X as 0 in the triggered DCI. Upon receiving this triggered DCI, the UE transmits the first part of a single HARQ-ACK codebook and discards the second part.

[0097] In embodiments, the retransmitted ACK indication (RAI) may also be referred to as "same ACK indication," "outdated ACK indication," or "previous / earlier ACK indication." This disclosure is not limited thereto.

[0098] In some embodiments, the second part of a single HARQ-ACK codebook includes the most recently received New Data Indication (NDI) bits for X DL HARQ processes.

[0099] In this embodiment, the total size of a single HARQ-ACK codebook is equal to N*C*M+C*X, where N is the number of configured DLHARQ processes, C is the maximum number of RRC configurations for a TB carried on a PDSCH, and M is the maximum number of RRC configurations for a CBG per TB. When spatial bundling is used or only one TB can be carried on a single PDSCH, C equals 1. When no CBG-based retransmission is configured, M equals 1.

[0100] Since 1 NDI bit corresponds to 1 TB, when 2 TB are carried on 1 PDSCH, there are 2 NDI bits in the DCI of the PDSCH scheduling.

[0101] For a given HARQ process, each NDI bit in the second part is the most recently received NDI bit of the UE's TB. For simplicity, in the example below, it is assumed that a PDSCH can only carry one TB and no CBG-based retransmission is configured. Such a configuration is for illustrative purposes only, and this disclosure is not intended to be limited thereto.

[0102] like Figure 6 As shown in the diagram, assuming that the NDI is "0" in the DCI that schedules PDSCH in time slots n, n+1, n+2, and n+3, for HARQ process x, the UE reports a in time slot n+4. x As an ACK, the gNB sends a DCI using the handover NDI ("1") in time slot m to schedule a new TB transmission. If the UE misses this DCI in time slot m, the UE will retransmit a in a single HARQ-ACK codebook. x (That is, the ACK for PDSCH in slot n), as b in the first part xFurthermore, for the HARQ process x in the second part, the NDI is indicated as "0" because the latest NDI received at the UE side in slot n is "0".

[0103] For HARQ process x+1, the UE will use a in time slot n+4. x+1 The report is ACK, and the gNB sends a DCI using the switched NDI (“1”) in time slot m+1 to schedule the new TB transmission. When the UE detects this DCI in time slot m+1 to schedule HARQ process x+1 and correctly decodes the associated PDSCH, the UE will generate an ACK as b in the first part of the single HARQ-ACK codebook. x+1 And in the second part, it indicates to the HARQ process x+1 that the latest NDI it received in slot m+1 is "1".

[0104] Thus, after receiving a single HARQ-ACK codebook at the gNB side, for a given HARQ process, the gNB can determine whether the DCI has been lost by comparing the most recently sent NDI bit in the DCI with the NDI bit received in the second part of the single HARQ-ACK codebook.

[0105] exist Figure 6 In the example shown, at the gNB side, for HARQ process x, the latest NDI bit is "1", which is transmitted in the DCI of time slot m. However, the NDI bit received in the second part of the single HARQ-ACK codebook is "0". Because these two bits are different, the gNB knows that the DCI in time slot m has been lost and will schedule retransmission of data in the next time slot. Similarly, at the gNB side, for HARQ process x+1, the latest NDI bit is "1", which is transmitted in the DCI of time slot m+1, and the NDI bit received in the second part of the single HARQ-ACK codebook is also "1". Therefore, the gNB knows that the DCI in time slot m+1 has not been lost, and the associated PDSCH has been correctly decoded, and the gNB will schedule the transmission of new data in a subsequent time slot.

[0106] Because the NDI bit in the second part indicates the latest received NDI for a given HARQ process's TB, a mapping relationship is established between the NDI bit and the corresponding HARQ process.

[0107] In one embodiment, X is set to the number of configured DL HARQ processes. Here, each C bits of the C*X NDI bits in the second part of a single HARQ-ACK codebook corresponds to one configured HARQ process, where C is the maximum number of TB RRC configurations that can be carried on a PDSCH. Each group of C bits corresponds to one TB. A disadvantage of this embodiment is the high signaling overhead when configuring 16 DL HARQ processes.

[0108] In one embodiment, X is set to a fixed value according to a standard or a semi-static value configured by RRC signaling. For example, X is 2, 4, 8, or other values. The gNB can configure an appropriate value for X based on the statistical probability of error conditions occurring, where X is less than the number configured by the DL HARQ process. The following options can be used.

[0109] Option 1: The C*X NDI bits in Part 2 correspond to the first X HARQ processes of a subset S of N configured HARQ processes, where each of the HARQ processes in subset S or each of the S HARQ processes is reported with an ACK in both the previous HARQ-ACK codebook and the current single HARQ-ACK codebook. For simplicity, in the example below, assume that a PDSCH can only carry one TB and no CBG-based retransmission is configured. Here, one NDI bit is included in the DCI in the scheduled PDSCH.

[0110] like Figure 6 As shown, for HARQ process x, if a x =ACK and b x =NACK, then HARQ process x will not be included in the S HARQ processes; if a x =NACK and b x =ACK, then HARQ process x is also not included in the S HARQ processes; and only if a x =ACK and b x When =ACK, HARQ process x is included in S HARQ processes.

[0111] Here, the second part only includes the corresponding NDI bits for the first X processes of the S HARQ processes. By comparing the two HARQ-ACK codebooks, the gNB can determine which HARQ process the reported NDI bits correspond to. If S > X, the last X HARQ processes of the S processes are not reported with the corresponding NDI bits. If S = 0, the second part is padded with X "NACK" bits or "ACK" bits.

[0112] For example, for HARQ processes x, x+1, x+2, and x+3, (ACK, ACK, NACK, ACK) are reported in time slot n+4. The UE loses DCI in time slot m, detects DCI in time slot m+1, and correctly decodes the PDSCH scheduled by DCI in time slot m+1. Assuming S=2 and X=4, the UE then reports ACK. In the first part of the single HARQ-ACK codebook, ACK is reported for HARQ processes x and x+1, and in the second part, four NDI bits are indicated as 0, 1, 0, 0, where "1" indicates that the most recently received NDI for HARQ process x+1 is 1, the first "0" indicates that the most recently received NDI for HARQ process x is 0, and the last two "0"s are padding bits. Assuming X=4 and N=6, the UE reports 4 NDI bits, "0, 1, 0, 0", which correspond to the first 4 of the 6 HARQ processes. The first "0" indicates that the most recently received NDI for HARQ process x is 0, the "1" indicates that the most recently received NDI for HARQ process x+1 is 1, and the last two "0"s indicate the latest NDI bits for the third and fourth HARQ processes out of the 6 HARQ processes.

[0113] For a given HARQ process, the gNB can determine whether the DCI has been lost by comparing the most recently transmitted NDI bit and the received NDI bit in the DCI of the second part of a single HARQ-ACK codebook. Figure 6 In the example shown, by comparing the most recently sent NDI bit "1" and the received NDI bit "0" of the HARQ-ACK process x in the second part of the HARQ-ACK codebook, the gNB can determine that the DCI was lost in time slot m and will retransmit the lost DCI in the next time slot.

[0114] If the first HARQ-ACK codebook (or the previous HARQ-ACK codebook) is not correctly received by the gNB due to hidden node interference, or if the previous HARQ-ACK codebook is not sent by the UE due to LBT failure, the gNB detects the first part of the single HARQ-ACK codebook and ignores the second part.

[0115] Option 2: The C*X NDI bits in the second part correspond to the last X HARQ processes of a subset S of the configured HARQ processes, where each of the S HARQ processes is reported with an ACK in both the previous HARQ-ACK codebook and the current single HARQ-ACK codebook. The details for determining the S HARQ processes and NDI bits are similar to those in Option 1.

[0116] In one embodiment, X is dynamically indicated during the triggering of the DCI. By dynamically indicating X during the triggering of the DCI, the gNB can adaptively adjust the value of X based on the number of ACK bits received in the previous HARQ-ACK codebook.

[0117] For example, suppose there are Z1 HARQ processes reported with ACK in the previous HARQ-ACK codebook, and the gNB schedules Z2 HARQ processes (from the previous Z1 HARQ processes) for new data transmission between the previous HARQ-ACK codebook and the current triggering DCI with the switched NDI. Theoretically, when all Z2 HARQ processes are correctly decoded by the UE and acknowledged with ACK, at most Z2 HARQ processes would require the NDI bit in the second part of a single HARQ-ACK codebook. In this case, setting the X value to Z2 in the triggering DCI can resolve the error situation.

[0118] like Figure 6 As shown in the figure, assuming 4 HARQ-ACK information bits a x a x+1 a x+2 a x+3 If the values ​​are ACK, ACK, NACK, and ACK respectively, then there are three HARQ processes reporting ACK in the Type 1 HARQ-ACK codebook: HARQ processes x, x+1, and x+3. Further assuming that HARQ processes x and x+1 are scheduled for new data transmission in time slots m and m+1 respectively, that is, two HARQ processes from the aforementioned three HARQ processes are scheduled between the Type 1 HARQ-ACK report and the single-trigger DCI. Therefore, at most two HARQ processes can be reported in both the Type 1 HARQ-ACK codebook and the single-trigger HARQ-ACK codebook: HARQ processes x and x+1. In this case, the gNB can indicate the value of X as 2 in the trigger DCI, where two NDI bits are sufficient to avoid error conditions.

[0119] After receiving the trigger DCI, the UE can set the value of X to 2 and generate 2 NDI bits in the second part of the single HARQ-ACK codebook corresponding to HARQ processes x and x+1.

[0120] The number of bits used to indicate X in triggering DCI is equal to ceil(log2(N)), where N is the number of configured DL HARQ processes. When 16 HARQ processes are configured, in extreme cases, both the previous HARQ-ACK codebook and the single HARQ-ACK codebook require 4 bits to indicate the maximum of 16 HARQ processes that have reported ACKs.

[0121] In some cases, if the first HARQ-ACK codebook (or the previous HARQ-ACK codebook) is not correctly received by the gNB due to hidden node interference, or is not transmitted by the UE due to LBT failure, the gNB will indicate X as 0 in the triggered DCI. Upon receiving this triggered DCI, the UE transmits the first part of a single HARQ-ACK codebook and discards the second part.

[0122] Figure 7 The diagram illustrates the flowchart of the single HARQ-ACK codebook determination steps at the UE side.

[0123] In step 702, receiver 214 on the UE side receives a first signal (e.g., RRC signaling) configuring multiple downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal (e.g., triggering DCI) triggering HARQ-ACK feedback for each of the multiple DL HARQ processes.

[0124] At step 704, the transmitter 212 on the UE side transmits a HARQ-ACK codebook including a first part, which includes HARQ-ACK feedback for each of the multiple DL HARQ processes.

[0125] The HARQ-ACK feedback for each of the multiple DL HARQ processes can be concatenated in the first part according to the order of the HARQ process IDs.

[0126] The HARQ-ACK codebook may further include a second part, and each bit in the second part corresponds to the number of HARQ processes that have reported a positive response to the HARQ process in the first part. Details regarding the determination of the HARQ-ACK codebook are referenced above. Figure 5 and Figure 6 This has been discussed and therefore will not be repeated here. The processor 202 on the UE side can perform the processing required for HARQ-ACK codebook determination, such as the determination of the first and second parts.

[0127] Figure 8 This is a flowchart illustrating the steps involved in determining a single HARQ-ACK codebook on the gNB side.

[0128] At step 802, the transmitter 312 on the gNB side sends a first signal (e.g., RRC signaling) configuring multiple downlink (DL) hybrid automatic repeat request (HARQ) processes and a second signal (e.g., triggering DCI) triggering HARQ-ACK feedback for each of the multiple DL HARQ processes.

[0129] At step 804, receiver 314 on the gNB side receives a HARQ-ACK codebook including a first portion, which includes HARQ-ACK feedback for each of the plurality of DL HARQ processes.

[0130] The HARQ-ACK feedback for each of the multiple DL HARQ processes can be concatenated in the first part according to the order of the HARQ process IDs.

[0131] The HARQ-ACK codebook may further include a second part, in which each bit corresponds to a number of DL HARQ processes with a positive response reported by the HARQ process in the first part.

[0132] The processor 302 on the gNB side can perform the processing required to decode the HARQ-ACK codebook.

[0133] By publishing the HARQ-ACK codebook, misunderstandings between the gNB and UE regarding a single HARQ-ACK codebook can be avoided.

[0134] Various embodiments and / or examples are disclosed to provide exemplary and illustrative information, enabling those skilled in the art to put the disclosure into practice. Unless otherwise specifically indicated, features or components disclosed with reference to one embodiment or example are also applicable to all embodiments or examples.

[0135] The embodiments may be practiced in other specific forms. These embodiments should be considered in all respects as illustrative rather than restrictive. Therefore, the scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations within the meaning and scope of the equivalents of the claims are covered within their scope.

Claims

1. A user equipment (UE), comprising: A receiver that receives a first signal configuring multiple downlink (DL) Hybrid Automatic Repeat Request (HARQ) processes and a second signal triggering a HARQ acknowledgment (HARQ-ACK) response for each of the multiple DL HARQ processes, wherein the first signal is RRC signaling and the second signal is downlink control information (DCI); and A transmitter sends a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion comprising HARQ-ACK feedback for each of the plurality of DL HARQ processes, wherein the HARQ-ACK feedback for each of the plurality of DL HARQ processes is concatenated in the first portion according to the order of the HARQ process IDs. The HARQ-ACK codebook further includes a second part, and each bit in the second part corresponds to a HARQ process in the plurality of DL HARQ processes that reported a positive response to the HARQ process in the first part.

2. The UE according to claim 1, wherein, Each bit in the second part indicates whether the positive response in the first part for the HARQ process is a retransmission from an earlier HARQ-ACK feedback or an initial transmission.

3. The UE according to claim 1, wherein, The second part comprises X bits, and X is equal to the number of DL HARQ processes.

4. The UE according to claim 3, wherein, Each bit in the second part corresponds to one of the plurality of DLHARQ processes.

5. The UE according to claim 1, wherein, The second part comprises X bits, and X is configured by Radio Resource Control (RRC) signaling.

6. The UE according to claim 5, wherein, The X bits correspond to the first X HARQ processes of a subset of the plurality of DL HARQ processes, wherein each of the subsets of the plurality of DL HARQ processes is reported as having an affirmative response in both the earlier HARQ-ACK codebook and the HARQ-ACK codebook.

7. The UE according to claim 5, wherein, The X bits correspond to the last X HARQ processes of a subset of the plurality of DL HARQ processes, wherein each of the subsets of the plurality of DL HARQ processes is reported as having an affirmative response in both the earlier HARQ-ACK codebook and the HARQ-ACK codebook.

8. The UE according to claim 1, wherein, The second part comprises X bits, and X is indicated in the second signal.

9. The UE according to claim 8, wherein, X equals the number of positive acknowledgment bits in the earlier HARQ-ACK codebook.

10. The UE according to claim 8, wherein, X equals the number of DL transmissions between the first time instance used to report the earlier HARQ-ACK codebook and the second time instance used to report the HARQ-ACK codebook.

11. The UE according to claim 1, wherein, Each bit in the second part indicates whether the positive response to the HARQ process in the first part is the same as or different from the earlier HARQ-ACK feedback.

12. The UE according to claim 1, wherein, Each bit in the second part indicates whether the positive response in the first part for the HARQ process is a new positive response or an outdated positive response.

13. The UE according to claim 1, wherein, Each bit in the second part is the most recently received New Data Indicator (NDI) bit corresponding to the HARQ process.

14. The UE according to claim 1, wherein, Each bit in the second part is the most recently received New Data Indicator (NDI) bit corresponding to the transport block of the HARQ process.

15. A network entity (NE), comprising: A transmitter that sends a first signal configuring multiple downlink (DL) Hybrid Automatic Repeat Request (HARQ) processes and a second signal triggering a HARQ-ACK response for each of the multiple DL HARQ processes, wherein the first signal is RRC signaling and the second signal is downlink control information (DCI); and A receiver receives a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion comprising HARQ-ACK feedback for each of the plurality of DL HARQ processes, wherein the HARQ-ACK feedback for each of the plurality of DL HARQ processes is concatenated in the first portion according to the order of the HARQ process IDs. The HARQ-ACK codebook further includes a second part, and each bit in the second part corresponds to a HARQ process in the plurality of DL HARQ processes that reported a positive response to the HARQ process in the first part.

16. The NE according to claim 15, wherein, Each bit in the second part indicates whether the positive response in the first part for the HARQ process is a retransmission from an earlier HARQ-ACK feedback or an initial transmission.

17. The NE according to claim 15, wherein, The second part comprises X bits, and X is equal to the number of DLHARQ processes.

18. The NE according to claim 17, wherein, Each bit in the second part corresponds to one of the plurality of DLHARQ processes.

19. The NE according to claim 15, wherein, The second part comprises X bits, and X is configured by Radio Resource Control (RRC) signaling.

20. The NE according to claim 19, wherein, The X bits correspond to the first X HARQ processes of a subset of the plurality of DL HARQ processes, wherein each of the subsets of the plurality of DL HARQ processes is reported as having an affirmative response in both the earlier HARQ-ACK codebook and the HARQ-ACK codebook.

21. The NE according to claim 19, wherein, The X bits correspond to the last X HARQ processes of a subset of the plurality of DL HARQ processes, wherein each of the subsets of the plurality of DL HARQ processes is reported as having an affirmative response in both the earlier HARQ-ACK codebook and the HARQ-ACK codebook.

22. The NE according to claim 15, wherein, The second part comprises X bits, and X is indicated in the second signal.

23. The NE according to claim 22, wherein, X equals the number of positive acknowledgment bits in the earlier HARQ-ACK codebook.

24. The NE according to claim 22, wherein, X equals the number of DL transmissions between the first time instance used to report the earlier HARQ-ACK codebook and the second time instance used to report the HARQ-ACK codebook.

25. The NE according to claim 15, wherein, Each bit in the second part indicates whether the positive response to the HARQ process in the first part is the same as or different from the earlier HARQ-ACK feedback.

26. The NE according to claim 15, wherein, Each bit in the second part indicates whether the positive response in the first part for the HARQ process is a new positive response or an outdated positive response.

27. The NE according to claim 15, wherein, Each bit in the second part is the most recently received New Data Indicator (NDI) bit corresponding to the HARQ process.

28. The NE according to claim 15, wherein, Each bit in the second part is the most recently received New Data Indicator (NDI) bit corresponding to the transport block of the HARQ process.

29. A method performed by a user equipment (UE), comprising: The system receives a first signal configuring multiple downlink (DL) Hybrid Automatic Repeat Request (HARQ) processes and a second signal triggering a HARQ acknowledgment (HARQ-ACK) response for each of the multiple DL HARQ processes, wherein the first signal is RRC signaling and the second signal is downlink control information (DCI); and Send a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion, the first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes, wherein the HARQ-ACK feedback for each of the plurality of DL HARQ processes is concatenated in the first portion according to the order of HARQ process ID. The HARQ-ACK codebook further includes a second part, and each bit in the second part corresponds to a HARQ process in the plurality of DL HARQ processes that reported a positive response to the HARQ process in the first part.

30. A method performed by a network entity (NE), comprising: Sending a first signal configuring multiple downlink (DL) Hybrid Automatic Repeat Request (HARQ) processes and a second signal triggering HARQ acknowledgment (HARQ-ACK) feedback for each of the multiple DL HARQ processes, wherein the first signal is RRC signaling and the second signal is downlink control information (DCI); and Receive a HARQ-ACK codebook, wherein the HARQ-ACK codebook includes a first portion, the first portion including HARQ-ACK feedback for each of the plurality of DL HARQ processes, wherein the HARQ-ACK feedback for each of the plurality of DL HARQ processes is concatenated in the first portion according to the order of HARQ process ID. The HARQ-ACK codebook further includes a second part, and each bit in the second part corresponds to a HARQ process in the plurality of DL HARQ processes that reported a positive response to the HARQ process in the first part.

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