Method and device for adapting contention window size of unlicensed NR

Abstract

A method of a base station (BS) in a wireless communication system is provided. The method includes: receiving a hybrid automatic repeat request acknowledgement / negative acknowledgement (HARQ‑ACK / NACK) response set from at least one user equipment (UE) via an uplink channel, the response set corresponding to a downlink transmission sent to at least one UE; determining a time domain and frequency domain resource set containing a non-broadcast physical downlink shared channel (PDSCH) transmission on a downlink transmission burst previously sent to at least one UE; adjusting a contention window size (CWS) based on a subset of the HARQ‑ACK / NACK response set, the HARQ‑ACK / NACK response subset corresponding to a unicast PDSCH transmission on the determined time domain and frequency domain resource set; performing a listen-before-talk (LBT) operation with a configurable sensing duration based on the adjusted CWS; and sending a downlink transmission via a downlink channel based on the LBT operation.

Description

Technical Field

[0001] The present disclosure generally relates to contention window size adaptation. In particular, the present disclosure relates to HARQ-ACK feedback resource determination for NR-U CWS (contention window size) adaptation in an advanced wireless communication system, NR-U CWS adaptation rules, and NR-U CWS for wideband operation of NR-U. Background Art

[0002] In order to meet the increasing demand for wireless data services since the deployment of the fourth generation (4G) communication system, efforts have been made to develop an improved fourth generation (5G) or quasi-5G communication system. 5G or quasi-5G communication systems are also called "super 4G networks" or "post-long term evolution (LTE) systems". 5G communication systems are considered to be implemented in higher frequency (mmWave) bands, for example, 60GHz bands, to achieve higher data rates. In 5G communication systems, in order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming and large antenna technologies are discussed. In addition, in 5G communication systems, development of system network improvements based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc. is underway. In 5G systems, hybrid frequency shift keying (FSK) and Feher's quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The Internet is a human-centered connectivity network where humans generate and consume information, and is now evolving into the Internet of Things (IoT), in which distributed entities such as things exchange and process information without human intervention. The Internet of Everything, which combines IoT technology and big data processing technology through connection with cloud servers, has emerged. To realize the IoT, technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", "security technology" are required, and sensor networks, machine-to-machine (M2M) communication, machine-type communication (MTC), etc. have been studied recently. This IoT environment can provide smart Internet technology services to create new value for human life by collecting and analyzing data generated between connected things. Through the integration and combination between existing information technology (IT) and various industrial applications, IoT can be applied to various fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart appliances, and advanced medical services.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT. For example, technologies such as sensor networks, MTC, and M2M communications are realized by technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN, which is a big data processing technology as described above, can also be considered as an example of the fusion between 5G technology and IoT technology.

[0005] As described above, various services can be provided according to the development of wireless communication systems, and thus a method for easily providing the services is required. Summary of the invention

[0006] Embodiments of the present disclosure provide a method and apparatus for adapting a contention window size for an unlicensed NR in an advanced wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which like reference numerals represent like components:

[0008] Figure 1 An exemplary wireless network according to an embodiment of the present disclosure is shown.

[0009] Figure 2 An exemplary gNB according to an embodiment of the present disclosure is shown.

[0010] Figure 3 An exemplary UE according to an embodiment of the present disclosure is shown.

[0011] Figure 4A A high level diagram of an OFDMA transmission path according to an embodiment of the present disclosure is shown.

[0012] Figure 4B A high level diagram of an OFDMA receive path according to an embodiment of the present disclosure is shown.

[0013] Figure 5 A transmitter block diagram for PDSCH in a subframe according to an embodiment of the present disclosure is shown.

[0014] Figure 6 A receiver block diagram for PDSCH in a subframe according to an embodiment of the present disclosure is shown.

[0015] Figure 7 A transmitter block diagram for PUSCH in a subframe according to an embodiment of the present disclosure is shown.

[0016] Figure 8 A receiver block diagram for PUSCH in a subframe according to an embodiment of the present disclosure is shown.

[0017] Fig. 9 An exemplary multiplexing of two slices according to an embodiment of the present disclosure is shown.

[0018] Fig.10 An exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0019] Fig.11 Another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0020] Fig.12 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0021] Fig.13 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0022] Fig.14 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0023] Fig.15 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0024] Fig.16 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0025] Fig.17 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0026] Fig.18 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0027] Fig.19 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0028] Fig. 20 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0029] Fig.21 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0030] Fig. 22 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0031] Fig.23 Yet another exemplary set of time slots / mini-slots / partial time slots according to an embodiment of the present disclosure is shown.

[0032] Fig.24 An exemplary CB mapping according to an embodiment of the present disclosure is shown.

[0033] Fig.25 A flow chart of the listen-before-talk based channel access process in LAA is shown.

[0034] Fig.26 A flow chart of a method for multi-beam operation according to an embodiment of the present disclosure is shown.

[0035] Fig. 27 A block diagram showing the structure of a gNB according to an embodiment of the present disclosure.

[0036] Fig.28 A block diagram showing the structure of a user equipment (UE) according to an embodiment of the present disclosure.

[0037] Best Mode for Carrying Out the Invention

[0038] In one embodiment, a base station (BS) in a wireless communication system is provided. The BS includes a transceiver configured to receive a hybrid automatic repeat request-acknowledgement / negative acknowledgement (HARQ-ACK / NACK) response set from at least one user equipment (UE) via an uplink channel, the response set corresponding to a downlink transmission sent to at least one UE. The BS also includes a processor operably connected to the transceiver, the processor configured to: determine a time domain and frequency domain resource set containing a unicast physical downlink shared channel (PDSCH) transmission in a downlink transmission burst previously sent to at least one UE; adjust a contention window size (CWS) based on a subset of the HARQ-ACK / NACK response set, the HARQ-ACK / NACK response subset corresponding to a unicast PDSCH transmission on the determined time domain and frequency domain resource set; and perform a listen-before-talk (LBT) operation with a configurable sensing duration based on the adjusted CWS. The BS includes a transceiver, which is also configured to send a downlink transmission via a downlink channel based on the LBT operation.

[0039] In one embodiment, the time domain and frequency domain resource sets include at least one of a time slot set, a mini time slot set, or a partial time slot set based on a downlink transmission burst, and wherein: the time slots in the time slot set are determined on an unabridged PDSCH having a duration of 14 orthogonal frequency division multiplexing (OFDM) symbols; the mini time slots in the mini time slot set are determined on an unabridged PDSCH having a duration less than the duration of 14 OFDM symbols; and the partial time slots in the partial time slot set are determined on a truncated PDSCH having a duration equal to or less than the duration of 14 OFDM symbols.

[0040] In one embodiment, the time domain and frequency domain resource set is determined to start from a previously transmitted downlink transmission burst and end with the first K>=1 slots or mini-slots set including at least one unicast PDSCH transmission of at least one UE scheduled in the previously transmitted downlink transmission burst.

[0041] In one embodiment, the set of time and frequency domain resources is determined to start from a previously transmitted downlink transmission burst and end with the first K>=1 mini-slots or partial slots of the downlink transmission burst including the unicast PDSCH transmission.

[0042] In one embodiment, the previously transmitted downlink transmission burst is the most recent transmission burst when the BS performs a CWS (contention window size) adjustment decision, and wherein a HARQ-ACK / NACK feedback resource set corresponding to a determined time domain and frequency domain resource set is expected to be available or has been received.

[0043] In one embodiment, the BS includes a processor that is further configured to adjust the CWS based on: a proportion of NACKed transport blocks (TBs), when the proportion of NACKed code block groups (CBGs) exceeds a predetermined threshold, the HARQ-ACK based on the CBG is the NACKed TB; or a weighted average proportion of NACKed bits, wherein when the proportion of NACKed CBGs exceeds a predetermined threshold, the CWS is increased to the next available value; and when the proportion of NACKed CBGs is less than or equal to the predetermined threshold, the CWS is reset to a minimum value.

[0044] In one embodiment, the predetermined threshold is a non-decreasing threshold based on the ratio between the number of HARQ-ACK values ​​expected to be received at the timing when the BS performs the CWS adjustment operation and the number of HARQ-ACK values ​​corresponding to the HARQ-ACK / NACK feedback resource set for adjusting the CWS.

[0045] In one embodiment, each ACK / NACK feedback bit in the HARQ-ACK / NACK feedback resource set is provided to adjust the CWS at most once.

[0046] In one embodiment, the BS includes a processor that is further configured to: maintain the CWS without adjustment based on a predetermined maximum channel occupancy time (COT) when a HARQ-ACK / NACK feedback resource set is not available, and wherein the HARQ-ACK / NACK feedback resource set corresponds to a time domain and frequency domain resource set of a previously sent downlink transmission burst.

[0047] In one embodiment, the BS includes a processor further configured to receive a radio resource measurement (RRM) report from at least one UE, the RRM report including at least one of a signal strength indicator, a channel occupancy report, or a measurement report associated with an unlicensed new radio (NR-U) wake-up signal. The BS includes a processor further configured to adjust the CWS based on the RRM report and a threshold associated with the measurement quality.

[0048] In another embodiment, a method of a base station (BS) in a wireless communication system is provided. The method includes: receiving a hybrid automatic repeat request acknowledgement / negative acknowledgement (HARQ-ACK / NACK) response set from at least one user equipment (UE) via an uplink channel, the response set corresponding to a downlink transmission sent to at least one UE; determining a time domain and frequency domain resource set, which contains a non-broadcast physical downlink shared channel (PDSCH) transmission on a downlink transmission burst previously sent to the UE; adjusting a contention window size (CWS) based on a subset of the HARQ-ACK / NACK response set, the HARQ-ACK / NACK response subset corresponding to a unicast PDSCH transmission on the determined time domain and frequency domain resource set; performing a listen-before-talk (LBT) operation with a configurable sensing duration based on the adjusted CWS; and sending a downlink transmission via a downlink channel based on the LBT operation.

[0049] In another embodiment, a user equipment (UE) in a wireless communication system is provided. The UE includes a transceiver configured to: send a hybrid automatic repeat request acknowledgement / negative acknowledgement (HARQ-ACK / NACK) response set to a base station (BS) via an uplink channel, the response set corresponding to a downlink transmission received from the BS, wherein the HARQ-ACK / NACK feedback resource set corresponds to a downlink transmission on a time domain and frequency domain resource set based on a downlink transmission burst previously received from the BS; and receive a downlink transmission from the BS via a downlink channel based on a listen-before-talk (LBT) operation at the BS, wherein the LBT operation with a configurable sensing duration is determined based on a contention window size (CWS), and the CWS is adjusted based on the HARQ-ACK / NACK feedback resource set.

[0050] Other technical features will be apparent to those skilled in the art from the following drawings, description and claims. DETAILED DESCRIPTION

[0051] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist understanding, but these are considered to be exemplary only. Thus, those of ordinary skill in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and brevity, descriptions of well-known functions and structures may be omitted.

[0052] The terms and words used in the accompanying description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable the present disclosure to be clearly and consistently understood. Thus, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only and not for limiting the disclosure as defined by the appended claims and their equivalents.

[0053] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0054] When describing the embodiments, technical contents that are well known in the related art and not directly related to the present disclosure will not be provided. By omitting redundant descriptions, the essence of the present disclosure will not be confused and can be clearly explained.

[0055] For the same reason, for the sake of clarity, components may be enlarged, omitted or schematically shown in the drawings. In addition, the size of each component does not fully reflect the actual size. In the drawings, the same reference numerals represent the same elements.

[0056] As used herein, the term "and / or" includes any and all combinations of one or more of the listed items that are associated. When a statement such as "at least one of" is before a list of elements, it modifies the entire list of elements rather than a single element in the list. Throughout the disclosure, the statement "at least one of a, b, or c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or a variation thereof. By referring to the following detailed description of the embodiments and the accompanying drawings, the advantages and features of one or more embodiments of the present disclosure and the method for realizing the present disclosure can be more easily understood. In this regard, this embodiment may have different forms and should not be construed as being limited to the description set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and the concept of this embodiment is fully conveyed to a person of ordinary skill in the art, and the present disclosure is limited only by the appended claims.

[0057] Here, it will be understood that the combination of blocks in a flowchart or process flow diagram can be performed by computer program instructions. Since computer program instructions can be loaded into a processor of a general-purpose computer, a special-purpose computer, or another programmable data processing device, the instructions executed by the processor of the computer or another programmable data processing device create a unit for performing the functions described in the flowchart box. Computer program instructions can be stored in a computer-usable memory or a computer-readable memory, and it can be known that the computer or another programmable data processing device implements the function in a specific manner, so the instructions stored in the computer-usable memory or the computer-readable memory can also generate a product containing an instruction unit for performing the functions described in the flow box. Computer program instructions can also be loaded into a computer or another programmable data processing device, and thus, when a series of operations are performed in a computer, the instructions for operating the computer or another programmable data processing device by generating a computer execution process can provide operations for performing the functions described in the flow box.

[0058] In addition, each frame may represent a module, segment or part of code including one or more executable instructions for performing a specific logical function. It should also be noted that in some alternative implementations, the functions mentioned in the frame may not be performed in order. For example, two frames shown in succession may actually be performed substantially simultaneously, or these frames may sometimes be performed in reverse order according to the corresponding functions.

[0059] Here, the term "unit" in the embodiments of the present disclosure represents a software component or hardware component such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and performs a specific function. However, the term "unit" is not limited to software or hardware. A "unit" may be formed to be in an addressable storage medium, or may be formed to operate one or more processors. Thus, for example, the term "unit" may refer to components such as software components, object-oriented software components, class components, and task components, and may include processes, functions, attributes, programs, subroutines, program code segments, drivers, firmware, macro codes, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by components and "units" may be associated with a smaller number of components and "units", or may be divided into additional components and "units". In addition, components and "units" may be implemented as regenerating one or more central processing units (CPUs) in a device or a secure multimedia card. In addition, in an embodiment, a "unit" may include at least one processor. In the present disclosure, a controller may also be referred to as a processor.

[0060] The term "connection" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not these elements are in physical contact with each other. The terms "send", "receive" and "communication" and their derivatives cover direct and indirect communication. The terms "include" and "comprise" and their derivatives are meant to include without limitation. The term "or" is inclusive, meaning and / or. The phrase "associated with..." and its derivatives mean to include, include within, interconnect with, include, include within, connect to or connect with, connect to or connect with, communicate with, collaborate with, interweave, parallel, approach, bind to or bind with, have, have the characteristics of, have... and... The relationship etc. of. The term "controller" refers to any device, system or part thereof that controls at least one operation. Such a controller can be implemented in hardware or a combination of hardware and software and / or firmware. Whether local or remote, the functions associated with any particular controller can be centralized or distributed. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one of the items in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0061] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and implemented in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, examples, related data or parts thereof that are suitable for implementation with suitable computer-readable program codes. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disc (CD), a digital video disc (DVD) or any other type of memory. "Non-transitory" computer-readable medium excludes wired, wireless, optical or other communication links that transmit instantaneous electrical signals or other instantaneous signals. Non-transitory computer-readable media include media that can permanently store data, and media that can store data and then rewrite data, such as rewritable optical discs or erasable storage devices.

[0062] Definitions for certain other words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most, instances, such definitions apply to prior and future uses of such defined words and phrases.

[0063] In wireless communication networks, network access and radio resource management (RRM) are enabled by physical layer synchronization signals and higher layer (MAC) procedures. Specifically, a user equipment (UE) attempts to detect the presence of synchronization signals and at least one cell identity (CI) for initial access. Once the UE is in the network and associated with a serving cell, the UE monitors neighboring cells by attempting to detect synchronization signals of several neighboring cells and / or by measuring associated cell-specific reference signals (RS). For next generation cellular systems such as the third generation partnership-new radio access or interface (3GPP-NR), an efficient and unified radio resource acquisition or tracking mechanism is needed for various use cases such as enhanced mobile broadband (eMBB), ultra-reliable low latency (URLLC), massive machine type communication (mMTC), where each use case corresponds to a frequency band with different coverage requirements and different propagation losses.

[0064] The following discussion Figures 1 to 26 , and the various embodiments used to describe the principles of the present disclosure in this patent document are only for illustration and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0065] The following documents and standard descriptions are incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 36.211 v13.2.0, "E-UTRA, Physical channels and modulation"; 3GPP TS 36.212 v13.2.0, "E-UTRA, Multiplex and Channel coding"; 3GPP TS 36.213 v13.2.1, "E-UTRA, Physical Layer Procedures"; 3GPP TS 36.321 v13.2.0, "E-UTRA, Medium Access Control (MAC) protocol specification"; 3GPP TS 36.331 v13.2.0, "E-UTRA, Radio Resource Control (RRC) Protocol Specification"; ETSI EN 30100-1 893 V2.1.1 “5 GHz RLAN; Harmonized Standard covering the essential requirement of article 3.2 of Directive 2014 / 53 / EU”, 2017; ETSI EN 302 567 V2.1.1 “Multiple-Gigabit / s radio equipment operating in the 60 GHz band; Harmonized Standard covering the essential requirements of article 3.2 of Directive 2014 / 53 / EU”, 2017; 3GPP TR 36.889 V13.0.0 “Study on Licensed-Assisted Access to Unlicensed Spectrum”, 2015; 3GPP TS 36.213V15.0.0 "Evolved Universal Terrestrial Radio Access (E-UTRA)); Physical layer procedures (Release 15)", 2017; IEEE Standard 802.11-2016 "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", 2016; 3GPP TS38.211v15.2.0 "NR, Physical channels and modulation"; 3GPP TS28.212v15.2.0 "NR, Multiplexing and Channel coding"; 3GPP TS38.213v15.2.0 "NR, Physical Layer Procedure for control"; 3GPP TS 3GPP TS 38.214v15.2.0, "NR, Physical Layer Procedure For Data"; 3GPP TS 38.321v15.2.0 "NR, Medium Access Control (MAC) protocol specification", and 3GPP TS 38.331v15.2.0 "NR, Radio Resource Control (RRC) Protocol Specification".

[0066] From the following detailed description, the aspects, features and advantages of the present disclosure will become apparent only by illustrating a number of specific embodiments and implementations (including the best mode expected to be used to implement the present disclosure). The present disclosure is also capable of other and different embodiments, and its several details may be modified in various obvious aspects, all without departing from the spirit and scope of the present disclosure. Thus, the drawings and description are to be considered illustrative in nature, rather than restrictive. The present disclosure is shown in the figures of the accompanying drawings by way of example and not by way of limitation.

[0067] In the following, for the sake of brevity, both FDD (Frequency Division Duplex) and TDD (Time Division Duplex) are considered as duplexing methods for DL ​​and UL signaling.

[0068] Although the following exemplary description and implementation assumes Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA), the present disclosure may be extended to other OFDM-based transmission waveforms or multiple access schemes, such as Filtered-OFDM (F-OFDM).

[0069] The present disclosure encompasses several components that may be used in conjunction or combination with each other, or that may operate as independent solutions.

[0070] To meet the increasing demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called "beyond 4G networks" or "post-LTE systems."

[0071] 5G communication systems are considered to be implemented in higher frequency (mmWave) bands, such as the 60 GHz band, to achieve higher data rates. To reduce the propagation loss of radio waves and increase transmission coverage, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, large antenna technology, etc. are discussed in 5G communication systems.

[0072] In addition, in the 5G communication system, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul communication, mobile networks, collaborative communications, coordinated multi-point (CoMP) transmission and reception, interference mitigation and elimination, etc.

[0073] In 5G systems, hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as adaptive modulation and coding (AMC) techniques, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access techniques have been developed.

[0074] the following Figures 1 to 4B Various embodiments are described for implementing and using Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) communication techniques in a wireless communication system. Figures 1 to 3 The description is not meant to imply physical or architectural limitations to the manner in which various embodiments may be implemented. Various embodiments of the present disclosure may be implemented in any suitably arranged communications system.

[0075] Figure 1An exemplary wireless network according to an embodiment of the present disclosure is shown. Figure 1 The embodiment of the wireless network shown is for illustration only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0076] like Figure 1 As shown, the wireless network includes gNB 101, gNB 102, and gNB 103. gNB 101 communicates with gNB 102 and gNB 103. gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0077] gNB 102 provides wireless broadband access to network 130 for a first plurality of user equipment (UE) within coverage area 120 of gNB 102. The first plurality of UEs include: UE 111, which may be located in a small business (SB); UE 112, which may be located in an enterprise (E); UE 113, which may be located in a WiFi hotspot (HS); UE 114, which may be located in a first residence (R); UE 115, which may be located in a second residence (R); and UE 116, which may be a mobile device (M) such as a cellular phone, a wireless laptop computer, a wireless PDA, etc. gNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within coverage area 125 of gNB 103. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of gNB 101 to gNB 103 may communicate with each other and with UE 111 to UE 116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication technologies.

[0078] Depending on the network type, the term "base station" or "BS" may refer to any component (or set of components) configured to provide wireless access to a network, such as a transmission point (TP), a transmission-reception point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macro cell, a femto cell, a WiFi access point (AP), or other wireless enabling devices. The base station may provide wireless access according to one or more wireless communication protocols, for example, 5G 3GPP New Radio Interface / Access (NR), Long Term Evolution (LTE), Advanced LTE (LTE-A), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to indicate a network infrastructure component that provides wireless access to a remote terminal. In addition, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station", "subscriber station", "remote terminal", "wireless terminal", "reception point", or "user equipment". For convenience, the term "user equipment" or "UE" is used in this patent document to refer to a remote wireless device that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile phone or smartphone) or is generally considered a fixed device (e.g., a desktop computer or a vending machine).

[0079] The dashed lines illustrate the approximate extents of coverage areas 120 and 125, which are shown as approximately circular for purposes of illustration and explanation only. It should be clearly understood that coverage areas associated with gNBs, such as coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on the configuration of the gNB and changes in the radio environment related to natural and man-made obstacles.

[0080] As described in more detail below, one or more of UE 111 to UE 116 include circuits, programming, or a combination thereof for contention window adaptation for unlicensed NR in an advanced wireless communication system. In some embodiments, one or more of gNB 101 to gNB 103 include circuits, programming, or a combination thereof for CSI acquisition based on space-frequency compression in an advanced wireless communication system.

[0081] although Figure 1 An example of a wireless network is shown, but Figure 1Various changes may be made. For example, the wireless network may include any number of gNBs and any number of UEs in any suitable arrangement. In addition, gNB 101 may communicate directly with any number of UEs and provide wireless broadband access to network 130 to these UEs. Similarly, each gNB 102 and gNB 103 may communicate directly with network 130 and provide direct wireless broadband access to network 130 to the UEs. In addition, gNB 101, gNB 102 and / or gNB 103 may provide access to other or additional external networks such as an external telephone network or other types of data networks.

[0082] Figure 2 An exemplary gNB 102 according to an embodiment of the present disclosure is shown. Figure 2 The illustrated embodiment of gNB 102 is for illustration only, and Figure 1 gNB 101 and gNB 103 may have the same or similar configuration. However, gNBs have various configurations, and Figure 2 The scope of this disclosure is not limited to any particular implementation of gNB.

[0083] like Figure 2 As shown, gNB 102 includes multiple antennas 205a to 205n, multiple RF transceivers 210a to 210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. gNB 102 also includes a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0084] The RF transceivers 210a to 210n receive incoming RF signals from the antennas 205a to 205n, such as signals sent by UEs in the network 100. The RF transceivers 210a to 210n down-convert the incoming RF signals to produce IF or baseband signals. The IF or baseband signals are sent to the RX processing circuit 220, which generates processed baseband signals by filtering, decoding and / or digitizing the baseband or IF signals. The RX processing circuit 220 sends the processed baseband signals to the controller / processor 225 for further processing.

[0085] The TX processing circuit 215 receives analog or digital data (such as voice data, web data, email, or interactive video game data) from the controller / processor 225. The TX processing circuit 215 encodes, multiplexes, and / or digitizes the output baseband data to produce a processed baseband or IF signal. The RF transceivers 210a to 210n receive the output processed baseband or IF signals from the TX processing circuit 215 and up-convert the baseband or IF signals into RF signals that are transmitted via the antennas 205a to 205n.

[0086] The controller / processor 225 may include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller / processor 225 may control the RF transceivers 210a to 210n, the RX processing circuit 220, and the TX processing circuit 215 to receive forward channel signals and transmit reverse channel signals according to well-known principles. The controller / processor 225 may also support additional functions, such as more advanced wireless communication functions.

[0087] For example, the controller / processor 225 may support beamforming or directional routing operations to weight signals output from the plurality of antennas 205a to 205n differently to efficiently steer the output signals in a desired direction. Any of a variety of other functions may be supported in the gNB 102 by the controller / processor 225.

[0088] Controller / processor 225 is also capable of executing programs and other processes, such as an OS, that reside in memory 230. Controller / processor 225 may move data into or out of memory 230 as needed to execute a process.

[0089] The controller / processor 225 is also connected to a backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems via a backhaul connection or via a network. The interface 235 may support communication via any appropriate wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (e.g., a system supporting 5G, LTE, or LTE-A), the interface 235 may allow the gNB 102 to communicate with other gNBs via a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 may allow the gNB 102 to communicate with a larger network (such as the Internet) via a wired or wireless local area network or via a wired or wireless connection. The interface 235 includes any appropriate structure that supports communication via a wired or wireless connection (such as an Ethernet or RF transceiver).

[0090] Memory 230 is coupled to controller / processor 225. A portion of memory 230 may include RAM, and another portion of memory 230 may include flash memory or other ROM.

[0091] although Figure 2 An example of a gNB 102 is shown, but the Figure 2 For example, gNB 102 may include Figure 2As a specific example, an access point may include multiple interfaces 235, and the controller / processor 225 may support routing functionality for routing data between different network addresses. As another specific example, although shown as including a single TX processing circuit 215 instance and a single RX processing circuit 220 instance, the gNB 102 may include multiple TX processing circuit 215 instances and multiple RX processing circuit 220 instances (such as one instance per RF transceiver). Additionally, Figure 2 The various components in may be combined, further subdivided, or omitted, and additional components may be added according to specific needs. Figure 2 The gNB 102 shown in FIG. 1 may correspond to Fig. 27 2700 shown in FIG. Controller / processor 225 may correspond to processor 2710, for example.

[0092] Figure 3 An exemplary UE 116 is shown in accordance with an embodiment of the present disclosure. Figure 3 The embodiment of UE 116 shown is for illustration only, and Figure 1 UE 111 to UE 115 may have the same or similar configuration. However, UE has various configurations, and Figure 3 The scope of the present disclosure is not limited to any particular implementation of a UE.

[0093] like Figure 3 As shown, UE 116 includes antenna 305, radio frequency (RF) transceiver 310, TX processing circuit 315, microphone 320, and receive (RX) processing circuit 325. UE 116 also includes speaker 330, processor 340, input / output (I / O) interface (IF) 345, touch screen 350, display 355, and memory 360. Memory 360 includes operating system (OS) 361 and one or more applications 362.

[0094] RF transceiver 310 receives an incoming RF signal from antenna 305 transmitted by a gNB of network 100. RF transceiver 310 down-converts the incoming RF signal to produce an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to RX processing circuitry 325, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. RX processing circuitry 325 sends the processed baseband signal to speaker 330 (e.g., for voice data) or processor 340 for further processing (such as for web browsing data).

[0095] The TX processing circuit 315 receives analog or digital voice data from the microphone 320, or receives other outgoing baseband data (such as web data, email, or interactive video game data) from the processor 340. The TX processing circuit 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuit 315 and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 305.

[0096] The processor 340 may include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 to control the overall operation of the UE 116. For example, the processor 340 may control the RF transceiver 310, the RX processing circuit 325, and the TX processing circuit 315 to receive forward channel signals and send reverse channel signals according to well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0097] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processing for CSI reporting on the uplink channel. The processor 340 can move data into or out of the memory 360 as needed to perform the processing. In some embodiments, the processor 340 is configured to execute the application 362 based on the OS 361 or in response to a signal received from the gNB or operator. The processor 340 is also coupled to the I / O interface 345, which enables the UE 116 to connect to other devices, such as laptops and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0098] Processor 340 is also coupled to touch screen 350 and display 355. An operator of UE 116 may input data into UE 116 using touch screen 350. Display 355 may be a liquid crystal display, light emitting diode display, or other display capable of presenting text (such as from a website) and / or at least limited graphics.

[0099] Memory 360 is coupled to processor 340. A portion of memory 360 may include random access memory (RAM), and another portion of memory 360 may include flash memory or other read-only memory (ROM).

[0100] although Figure 3 An example of UE 116 is shown, but the Figure 3 Make various changes. For example, Figure 3The various components in the embodiment may be combined, further subdivided, or omitted, and additional components may be added as required. As a specific example, processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In addition, although Figure 3 The UE 116 is shown configured as a mobile phone or smart phone, but the UE may be configured to operate as other types of mobile or stationary devices. Figure 3 The UE 116 shown in FIG. 1 may correspond to Fig.28 UE 2800 shown in . For example, processor 340 may correspond to processor 2810.

[0101] Figure 4A This is a top-level diagram of a transmit path circuit. For example, the transmit path circuit may be used for orthogonal frequency division multiple access (OFDMA) communication. Figure 4B is a top-level diagram of a receive path circuit. For example, the receive path circuit can be used for orthogonal frequency division multiple access (OFDMA) communication. Figure 4A and Figure 4B In the embodiment, for downlink communication, the transmit path circuit may be implemented in the base station (gNB) 102 or the relay station, and the receive path circuit may be implemented in the user equipment (e.g., Figure 1 In other examples, for uplink communications, the receive path circuit 450 may be implemented in a base station (e.g., Figure 1 The transmission path circuit may be implemented in a user equipment (e.g., a gNB 102) or a relay station, and the transmission path circuit may be implemented in a user equipment (e.g., Figure 1 is implemented in the user device 116).

[0102] The transmit path circuitry includes a channel coding and modulation block 405, a serial to parallel (S to P) block 410, an inverse fast Fourier transform (IFFT) block of size N 415, a parallel to serial (P to S) block 420, an add cyclic prefix block 425, and an upconverter (UC) 430. The receive path circuitry 450 includes a downconverter (DC) 455, a remove cyclic prefix block 460, a serial to parallel (S to P) block 465, a fast Fourier transform (FFT) block of size N 470, a parallel to serial (P to S) block 475, and a channel decoding and demodulation block 480.

[0103] At least some components in Figures 4A400 and 4B 450 can be implemented in software, while other components can be implemented by configurable hardware or a mixture of software and configurable hardware. In particular, it should be noted that the FFT block and IFFT block described in this disclosure can be implemented as a configurable software algorithm, in which the value of the size N can be modified according to the implementation.

[0104] In addition, although the present disclosure relates to implementations of fast Fourier transform and inverse fast Fourier transform, this is merely illustrative and should not be construed as limiting the scope of the present disclosure. It is understood that in alternative implementations of the present disclosure, the fast Fourier transform function and the inverse fast Fourier transform function can be easily replaced by a discrete Fourier transform (DFT) function and an inverse discrete Fourier transform (IDFT) function, respectively. It is understood that for DFT and IDFT functions, the value of the N variable can be any integer (i.e., 1, 4, 3, 4, etc.), while for FFT and IFFT functions, the value of the N variable can be any integer as a power of 2 (i.e., 1, 2, 4, 8, 16, etc.).

[0105] In the transmit path circuit 400, the channel coding and modulation block 405 receives a set of information bits, applies coding (e.g., LDPC coding) and modulation (e.g., quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) to the input bits to produce a frequency domain modulation symbol sequence. The serial to parallel block 410 converts (i.e., demultiplexes) the serial modulation symbols into parallel data to produce N parallel symbol streams, where N is the IFFT / FFT size used in the BS 102 and the UE 116. The size-N IFFT block 415 then performs an IFFT operation on the N parallel symbol streams to produce a time domain output signal. The parallel to serial block 420 converts (i.e., multiplexes) the parallel time domain output symbols from the size-N IFFT block 415 to produce a serial time domain signal. The add cyclic prefix block 425 then inserts a cyclic prefix into the time domain signal. Finally, upconverter 430 modulates (ie, upconverts) the output of add cyclic prefix block 425 to RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before being converted to RF frequency.

[0106] The transmitted RF signal reaches UE 116 after passing through the wireless channel and performs the reverse operation relative to the operation at gNB 102. Downconverter 455 downconverts the received signal to baseband frequency, and remove cyclic prefix block 460 removes the cyclic prefix to produce a serial time domain baseband signal. Serial to parallel block 465 converts the time domain baseband signal into parallel time domain signals. Then, FFT block 470 of size N performs an FFT algorithm to produce N parallel frequency domain signals. Parallel to serial block 475 converts the parallel frequency domain signals into a sequence of modulated data symbols. Channel decoding and demodulation block 480 demodulates and decodes the modulation symbols to recover the original input data stream.

[0107] Each of gNB 101 to gNB 103 may implement a transmission path similar to that for transmitting in the downlink to user equipment 111 to user equipment 116, and may implement a reception path similar to that for receiving in the uplink from user equipment 111 to user equipment 116. Similarly, each of user equipment 111 to user equipment 116 may implement a transmission path corresponding to the architecture for transmitting in the uplink to gNB 101 to gNB 103, and may implement a reception path corresponding to the architecture for receiving in the downlink from gNB 101 to gNB 103.

[0108] Use cases for 5G communication systems have been identified and described. These use cases can be roughly categorized into three different groups. In one example, enhanced mobile broadband (eMBB) is identified as meeting high bit / sec requirements with less stringent requirements for latency and reliability. In another example, ultra-reliable and low latency (URLL) is identified as less stringent requirements for bits / sec. In yet another example, massive machine type communications (mMTC) is identified as the number of devices can be as many as 100,000 to 1 million / km 2 , but the requirements for reliability / throughput / latency may be less stringent. This scenario may also involve power efficiency requirements, as battery consumption may be minimized.

[0109] The communication system includes a downlink (DL) and an uplink (UL), where the downlink (DL) transmits signals from a transmission point such as a base station (BS) or NodeB to a user equipment (UE), and the uplink (UL) transmits signals from a UE to a reception point such as a NodeB. A UE (also commonly referred to as a terminal or mobile station) can be fixed or mobile and can be a cellular phone, a personal computer device, or an automatic device. An eNodeB, which is generally a fixed station, may also be referred to as an access point or other equivalent terms. For an LTE system, a NodeB is generally referred to as an eNodeB.

[0110] In a communication system such as an LTE system, a DL signal may include a data signal that transmits information content, a control signal that transmits DL control information (DCI), and a reference signal (RS) also known as a pilot signal. The eNodeB transmits data information through a physical DL shared channel (PDSCH). The eNodeB transmits DCI through a physical DL control channel (PDCCH) or an enhanced PDCCH (EPDCCH).

[0111] The eNodeB sends an acknowledgement in response to a data transport block (TB) transmission in the Physical Hybrid ARQ Indicator Channel (PHICH) from the UE. The eNodeB sends one or more of multiple types of RS including UE Common RS (CRS), Channel State Information RS (CSI-RS), or Demodulation RS (DMRS). CRS is sent on the DL system bandwidth (BW) and can be used by the UE to obtain channel estimates to demodulate data or control information or perform measurements. To reduce CRS overhead, the eNodeB may send CSI-RS with a smaller time domain and / or frequency domain density than CRS. DMRS can only be sent in the BW of the corresponding PDSCH or EPDCCH, and the UE can use DMRS to demodulate the data or control information in the PDSCH or EPDCCH, respectively. The transmission time interval for a DL channel is called a subframe and may have a duration of, for example, 1 millisecond.

[0112] DL signals also include the transmission of logical channels that carry system control information. When the DL signal transmits a master information block (MIB), the BCCH is mapped to a transmission channel called a broadcast channel (BCH); or when the DL signal transmits a system information block (SIB), the BCCH is mapped to a DL shared channel (DL-SCH). Most system information is included in different SIBs sent using DL-SCH. The presence of system information on the DL-SCH in a subframe can be indicated by the transmission of the corresponding PDCCH (transmitting a codeword with a cyclic redundancy check (CRC) scrambled with the system information RNTI (SI-RNTI)). Alternatively, scheduling information for SIB transmission can be provided in an earlier SIB, and scheduling information for the first SIB (SIB-1) can be provided by the MIB.

[0113] DL resource allocation is performed in units of subframes and physical resource blocks (PRBs). The transmission BW consists of frequency resource units called resource blocks (RBs). Each RB consists of subcarriers or resource elements (REs), such as 12 REs. One RB unit on a subframe is called a PRB. A total of 12 REs can be allocated to a UE for PDSCH transmission BW. M of RE PDSCH RBs.

[0114] The UL signal may include a data signal for transmitting data information, a control signal for transmitting UL control information (UCI), and a UL RS. The UL RS includes a DMRS and a sounding RS (SRS). The UE sends the DMRS only in the BW of the corresponding PUSCH or PUCCH. The eNodeB may use the DMRS to demodulate the data signal or the UCI signal. The UE sends the SRS to provide the eNodeB with UL CSI. The UE sends data information or UCI through its respective physical UL shared channel (PUSCH) or physical UL control channel (PUCCH). If the UE needs to send data information and UCI in the same UL subframe, the UE may multiplex both in the PUSCH. The UCI includes: hybrid automatic repeat request acknowledgement (HARQ-ACK) information for indicating correct (ACK) or incorrect (NACK) detection of a data TB in the PDSCH, or the absence of PDCCH detection (DTX); a scheduling request for indicating whether the UE has data in the UE's buffer; a rank indicator (RI); and channel state information (CSI) for enabling the eNodeB to perform link adaptation for PDSCH transmission to the UE. HARQ-ACK information is also sent by the UE in response to detection of the PDCCH / EPDCCH indicating release of a semi-persistently scheduled PDSCH.

[0115] The UL subframe includes two time slots. Each time slot includes a symbols, UCI, DMRS or SRS. The frequency resource unit of the UL system BW is a resource block (RB). A total of 10 RBs are allocated to the UE for transmission BW. N of REs RB RBs. For PUCCH, N RB = 1. The last subframe symbol can be used to multiplex SRS transmissions from one or more UEs. The number of subframe symbols available for data / UCI / DMRS transmission is If the last subframe symbol is used to send SRS, then N SRS =1, otherwise N SRS =0.

[0116] Figure 5 A transmitter block diagram 500 for PDSCH in a subframe according to an embodiment of the present disclosure is shown. Figure 5 The illustrated implementation of transmitter block diagram 500 is for illustration only. Figure 5 The scope of the present disclosure is not limited to any particular implementation of transmitter block diagram 500 .

[0117] like Figure 5As shown, information bits 510 are encoded by an encoder 520 (such as a turbo encoder) and modulated by a modulator 530 (e.g., using quadrature phase shift keying (QPSK) modulation). A serial-to-parallel (S / P) converter 540 generates M modulation symbols, which are then provided to a mapper 550 to map to REs selected by a transmission BW selection unit 555 for the allocated PDSCH transmission BW, a unit 560 applies an inverse fast Fourier transform (IFFT), and then a parallel-to-serial (P / S) converter 570 serializes the output to generate a time domain signal, which is filtered by a filter 580 to obtain a transmitted signal 590. Additional functions, such as data scrambling, cyclic prefix insertion, time windowing, interleaving, and other functions are well known in the art and are not shown for simplicity.

[0118] Figure 6 A receiver block diagram 600 for PDSCH in a subframe according to an embodiment of the present disclosure is shown. Figure 6 The implementation of diagram 600 shown in FIG. 6 is for illustration only. Figure 6 The scope of the present disclosure is not limited to any particular implementation of diagram 600 .

[0119] like Figure 6 As shown, received signal 610 is filtered by filter 620, RE 630 for the allocated receive BW is selected by BW selector 635, fast Fourier transform (FFT) is applied by unit 640, and the output is serialized by parallel-to-serial converter 650. Subsequently, demodulator 660 coherently demodulates the data symbols by applying a channel estimate obtained from a DMRS or CRS (not shown), and decoder 670 (such as a turbo decoder) decodes the demodulated data to provide an estimate of information data bits 680. For the sake of brevity, additional functions such as time windowing, cyclic prefix removal, descrambling, channel estimation, and deinterleaving are not shown.

[0120] Figure 7 A transmitter block diagram 700 for PUSCH in a subframe according to an embodiment of the present disclosure is shown. Figure 7 The implementation of block diagram 700 shown in FIG. 7 is for illustration only. Figure 7 The scope of the present disclosure is not limited to any particular implementation of block diagram 700 .

[0121] like Figure 7As shown, information data bits 710 are encoded by an encoder 720 (such as a turbo encoder) and modulated by a modulator 730. A discrete Fourier transform (DFT) unit 740 applies DFT to the modulated data bits, a transmission BW selection unit 755 selects REs 750 corresponding to the allocated PUSCH transmission BW, a unit 760 applies IFFT, and after cyclic prefix insertion (not shown), filtering is applied by a filter 770, thereby obtaining a transmitted signal 780.

[0122] Figure 8 A receiver block diagram 800 for PUSCH in a subframe is shown according to an embodiment of the present disclosure. Figure 8 The illustrated implementation of block diagram 800 is for illustration only. Figure 8 The scope of the present disclosure is not limited to any particular implementation of block diagram 800 .

[0123] like Figure 8 As shown, the received signal 810 is filtered by a filter 820. Subsequently, after removing the cyclic prefix (not shown), a unit 830 applies FFT, a receive BW selector 845 selects REs 840 corresponding to the allocated PUSCH receive BW, a unit 850 applies an inverse DFT (IDFT), a demodulator 860 coherently demodulates the data symbols by applying a channel estimate obtained from a DMRS (not shown), and a decoder 870 (such as a turbo decoder) decodes the demodulated data to provide an estimate of the information data bit 880.

[0124] In the next generation of cellular systems, a variety of use cases are envisioned that exceed the capabilities of LTE systems. A system (referred to as 5G or fifth generation cellular system) that is capable of operating both below 6 GHz and above 6 GHz (e.g., in the mmWave regime) is needed. In 3GPP TR 22.891, 74 5G use cases have been identified and described; these use cases can be roughly categorized into three different groups. The first group, referred to as "enhanced mobile broadband (eMBB)", targets high data rate services with less stringent latency and reliability requirements. The second group, referred to as "ultra-reliable and low latency (URLL)", targets applications with less stringent data rate requirements but low tolerance for latency. The third group, referred to as "massive machine type communications (mMTC)", targets a large number of low-power device connections (such as one million / km 2 ), which have less stringent reliability, data rate, and latency requirements.

[0125] In order to enable 5G networks to support such diverse services with different quality of service (QoS), a method called network slicing has been confirmed in the 3GPP specification. In order to efficiently use PHY resources and multiplex various slices (with different resource allocation schemes, mathematical systems and scheduling strategies) in DL-SCH, a flexible and independent frame or subframe design is used.

[0126] Fig. 9 An exemplary multiplexing of two slices 900 according to an embodiment of the present disclosure is shown. Fig. 9 The multiplexing implementation of two slices 900 shown in FIG. 1 is for illustration only. Fig. 9 The scope of the present disclosure is not limited to any particular implementation of the multiplexing of two slices 900 .

[0127] exist Fig. 9 Two exemplary examples of multiplexing two slices in a common subframe or frame are described in . In these exemplary embodiments, a slice may consist of one or two transmission instances, wherein one transmission instance includes a control (CTRL) component (e.g., 920a, 960a, 960b, 920b, or 960c) and a data component (e.g., 930a, 970a, 970b, 930b, or 970c). In embodiment 910, the two slices are multiplexed in the frequency domain, while in embodiment 950, the two slices are multiplexed in the time domain. The two slices may be sent using different mathematical sets.

[0128] The 3GPP specification supports up to 32 CSI-RS antenna ports, enabling the gNB to be equipped with a large number of antenna elements (such as 64 or 128). In this case, multiple antenna elements are mapped to one CSI-RS port. For next-generation cellular systems such as 5G, the maximum number of CSI-RS ports may remain the same or increase.

[0129] Extending 5G NR to unlicensed spectrum is an important part of the NR standard, and one of the most important design considerations for unlicensed operation is the channel access mechanism. The channel access mechanism is critical to meet regional rules (such as this one) required for listen-before-talk and to achieve fair coexistence between radio access technologies (RATs) coexisting in unlicensed bands. In LTE-LAA, the channel access mechanism is a necessary feature for authorized downlink / uplink transmissions.

[0130] The baseline channel access procedure, referred to as the Category 4 (CAT-4) channel access procedure, is a LBT mechanism with random backoff with a contention window size (CWS) of variable size.

[0131] In addition to the baseline channel access procedure, a CWS adaptation mechanism is defined in LTE-LAA to mitigate transmission conflicts. The CAT-4 LBT procedure defines four different channel access priority categories p, each with a different minimum allowed CWS and maximum allowed CWS and a corresponding maximum channel occupancy time (MCOT). If the eNB sends a transmission associated with channel access priority category p on a carrier, the eNB maintains a contention window value CW p and adjust the CW before generating a random backoff counter for the channel access process for the next transmission p Specifically, the following procedure is used: for each priority class p∈{1, 2, 3, 4}, let CW p is the minimum CWS for priority category p; and if at least Z=80% of the HARQ-ACK values ​​corresponding to the PDSCH transmissions in reference subframe k are determined to be NACKs, CWS is set to p Or each priority class p∈{1, 2, 3, 4} is increased to the next higher allowed value and remains in step 2; otherwise, return to step 1.

[0132] For LTE-LAA, reference subframe k is the starting subframe of the most recent transmission by the eNB on the carrier for which at least some HARQ-ACK feedback is expected. If the eNB does not detect a HARQ-ACK for a PDSCH transmission, or if the eNB detects a "DTX", "NACK / DTX" or "Any" state, it is counted as a NACK.

[0133] A CAT-4 LBT procedure similar to LTE-LAA can be used as a reference channel access mechanism for unlicensed NR (NR-U), and NR-U CWS adaptation can also be based on HARQ-ACK feedback from the UE. However, unlike LTE-LAA, where the HARQ-ACK feedback timing is set to a fixed 4ms in the LTE-LAA specification, NR supports a very flexible timing relationship from PDSCH transmission to its corresponding HARQ-ACK feedback.

[0134] In addition, NR also supports HARQ-ACK feedback based on code block groups (CBGs), compared to LTE-LAA which only supports HARQ-ACK feedback based on transport blocks (TBs). In addition, NR supports wideband operation, where each carrier can be up to 100MHz in the sub-7GHz band, compared to LTE-LAA's 20MHz carrier bandwidth. Due to NR's flexibility and new features, NR-U's CWS adaptation rules are also much more flexible than LTE-LAA's CWS adaptation rules.

[0135] The present disclosure focuses on the design aspects of contention window size adaptation supporting NR-U, including HARQ-ACK feedback resource determination for NR-U CWS adaptation, NR-U CWS adaptation rules, and NR-U CWS for wideband operation of NR-U. The present disclosure includes several embodiments, principles, methods, and examples that can be used in conjunction or combination with each other or can operate independently.

[0136] In the rest of this disclosure, sub-7GHz NR-U refers to NR-U operating in an unlicensed / shared band below 7 GHz (such as an unlicensed band of 5 GHz or an unlicensed / shared band of 6 GHz); above-7GHz NR-U refers to NR-U operating in an unlicensed / shared band above 7 GHz (such as an unlicensed band of 60 GHz).

[0137] In the present disclosure, a scheduled UE's PDSCH transmission refers to a scheduled UE's unicast or non-broadcast PDSCH transmission, excluding non-unicast transmissions such as SS / PBCH blocks, NR-U Discovery Reference Signal (DRS), or other broadcast channels (including rest system information (RMSI), other system information (OSI), and paging). In addition, a scheduled UE refers to a UE with unicast PDSCH transmission scheduled by a gNB.

[0138] In one embodiment, HARQ-ACK feedback resource determination for NR-U contention window adjustment is provided. In this embodiment, reference time domain and frequency domain resources for determining the NR-U contention window (CW) adjustment process are provided.

[0139] At least when the NR-U gNR starts to perform a new CAT-4 LBT procedure to initialize DL transmission in, for example, an NR-U timeslot with index n, the gNB identifies a HARQ-ACK value set corresponding to a previous DL transmission in a reference time and frequency domain resource set, wherein the HARQ-ACK value set corresponding to the reference time and frequency domain resource set may be used in determining a rule for the gNB to increase a CW value or reset a CW value.

[0140] In this embodiment, determining reference time domain and frequency domain resources, and determining a set of HARQ-ACK values ​​corresponding to a previous DL transmission that can be used for NR-U CWS adjustment are described in detail. In the following embodiments, the rules for determining whether the gNB increases the CW value or resets the CW value are described in detail.

[0141] In one example, the reference time domain and frequency domain resources for CW adjustment may be a determined time slot and / or mini-time slot and / or a set of partial time slots of a previous DL transmission burst determined on a carrier of the gNB.

[0142] In a sub-example, a time slot serving as a reference time domain resource for determining contention window size adjustment may refer to a PDSCH that is scheduled with 14 OFDM symbols and is sent without truncating in the time domain; a mini time slot serving as a reference time domain resource for determining contention window size adjustment may refer to a PDSCH that is scheduled with less than 14 OFDM symbols and is sent without truncating in the time domain; a partial time slot serving as a reference time domain resource for determining contention window adjustment may refer to a PDSCH that is scheduled with equal to or less than 14 OFDM symbols and is sent with truncating in the time domain.

[0143] In another sub-example, such as in the NR standard, a mini-slot contains a duration of 2 / 4 / 7 symbols, and a partial slot may contain a duration different from the full slot duration (e.g., a starting partial slot within the channel occupancy time, an ending partial slot within the channel occupancy time, or a truncated PDSCH, or a PDSCH with a duration other than 2 / 4 / 7 symbols).

[0144] In one example of the determined set of slots and / or mini-slots and / or partial slots, the determined set of slots and / or mini-slots and / or partial slots may be the first K slots and / or mini-slots and / or partial slots of the determined previous DL transmission burst.

[0145] In one instance, K may be fixed to a fixed value by the specification, or may be a value that scales with the subcarrier spacing (SCS), or may be dynamically determined based on the starting PDSCH format of a determined previous DL transmission burst. In one sub-example, K may be fixed to 1, in which case a HARQ-ACK value for transmission only on the first NR-U slot, mini slot, or partial slot may be used. In another sub-example, K may also be fixed to 2, for example, when the determined previous DL transmission burst starts from a partial slot or mini slot. For example, the determined time slot and / or mini slot and / or partial slot set when K=2 may be the initial partial slot at the beginning of the determined previous DL transmission burst plus the subsequent full slot. In another sub-example, the default value of K with a 15kHz NR-U SCS may be fixed, while the K values ​​with a 30kHz NR-U SCS and a 60kHz NR-U SCS may be 2 times and 4 times the K value with a 15kHz NR-U SCS, respectively, where SCS refers to the SCS of the downlink transmission.

[0146] In another example, K may be configurable. In one sub-example, K may be configured by a high-level parameter through the RRC layer. In another sub-example, K may be configured through downlink control information (DCI), such as introducing a DCI indicator field to indicate whether the corresponding PDSCH scheduled by the DCI may be used as part of the reference time and frequency domain resources for CW adjustment.

[0147] In another example, K may be changed dynamically according to a predetermined rule. In one sub-example, K may be changed dynamically according to the number of OFDM symbols in the initial partial time slot, so that when the number of OFDM in the initial partial time slot is greater than a threshold τ1 (for example, τ1=7), K=1 (i.e., only the initial partial time slot is used); otherwise K=2 (i.e., the initial partial time slot and the subsequent full time slot are used). In another sub-example, K may be changed dynamically according to the number of HARQ-ACK feedbacks received or expected to be received by the gNB for CW timing, wherein K may be changed dynamically to a value that allows at least τ2 HARQ-ACK feedbacks received or expected to be received by the gNB for CW timing. In another sub-example, K may be changed dynamically according to the number of UEs scheduled by the determined previous DL transmission burst (the gNB performs CW timing reception or expected reception), wherein K may be changed dynamically to a value that allows at least τ3 UEs HARQ-ACK feedbacks scheduled by the determined previous DL transmission burst (the gNB performs CW timing reception or expected reception).

[0148] Fig.10 An exemplary set of slots / mini-slots / partial slots 1000 is shown in accordance with an embodiment of the present disclosure. Fig.10 The set of slots / mini-slots / partial slots 1000 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.10 The scope of the present disclosure is not limited.

[0149] Fig.10 An illustration of an example of a determined set of time slots and / or mini-time slots and / or partial time slots is provided in , where K=2, and a first time slot and a second time slot of a determined previous DL transmission burst are a partial time slot and a full time slot, respectively.

[0150] In one example of a determined set of slots and / or mini-slots and / or partial slots, the determined set of slots and / or mini-slots may all be slots and / or mini-slots and / or partial slots of a determined previous DL transmission burst.

[0151] In one example of a determined set of time slots and / or mini-slots, the determined set of time slots and / or mini-slots and / or partial time slots may be the first time slot or mini-slot or partial time slot set for a determined previous DL transmission burst for unicast PDSCH transmission of the UE scheduled in the burst.

[0152] In a sub-example, for example when a non-unicast channel / signal (such as DRS) is multiplexed with PDSCH and only DRS is sent in an initial time slot / mini time slot / partial time slot of a determined previous DL transmission burst, the determined time slot / mini time slot / partial time slot does not have to be the initial time slot / mini time slot / partial time slot of the determined previous DL transmission burst.

[0153] In another sub-example, the determined set of time slots and / or mini-time slots and / or partial time slots may be considered to start from the determined previous DL transmission burst and end with the first time slot or mini-time slot or partial time slot of the determined previous DL transmission burst for unicast PDSCH transmission of the UE scheduled in the burst. This sub-example and the previous sub-example are equivalent when the CWS is adjusted based on the HARQ-ACK feedback corresponding to the unicast PDSCH transmission of the determined time slot or mini-time slot or partial time slot from the DL transmission burst.

[0154] In another sub-example, the determined slot and / or mini-slot and / or set of partial slots may be the first slot of a non-punctured PDSCH having a duration of 14 symbols for unicast PDSCH transmission of the determined previous DL transmission burst.

[0155] In another sub-example, the determined slot and / or mini-slot and / or set of partial slots may be the first mini-slot of a non-punctured PDSCH having a duration less than 14 symbols for unicast PDSCH transmission of the determined previous DL transmission burst.

[0156] In another sub-example, the determined slots and / or mini-slots and / or set of partial slots may be the first partial slots of a punctured PDSCH having a duration less than or equal to 14 symbols for unicast PDSCH transmission of the determined previous DL transmission burst.

[0157] In another sub-example, the determined time slot and / or mini-slot and / or partial time slot set can be the first time slot of an unpunctured PDSCH having a duration of 14 symbols; if no such time slot is available, it can be the first mini-slot of an unpunctured PDSCH having a duration of less than 14 symbols; and if no such time slot or mini-slot is available, it can be the first partial time slot of a punctured PDSCH having a duration less than or equal to 14 symbols.

[0158] In another sub-example, one or more UEs may be scheduled for the determined time slot / mini-slot / partial time slot. In another sub-example, this example may be generalized as follows: the determined time slot and / or mini-slot and / or partial time slot set may be the first time slot or mini-slot or partial time slot set of a determined previous DL transmission burst, where some HARQ-ACK feedback is expected.

[0159] Fig.11 Another exemplary set of slots / mini-slots / partial slots 1100 is shown in accordance with an embodiment of the present disclosure. Fig.11 The embodiment of the time slot / mini-time slot / partial time slot set 1100 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.11 The scope of the present disclosure is not limited.

[0160] Fig.11 An example is shown where slot n-4 is the first slot of a previous DL transmission burst determined for PDSCH transmission by the UE scheduled in the burst.

[0161] In one example of a determined set of time slots and / or mini-slots and / or partial time slots, the determined set of time slots and / or mini-slots and / or partial time slots may be the first time slot or mini-slot or partial time slot set of a determined previous DL transmission burst for unicast PDSCH transmission of a UE scheduled in the burst (or in a regular time slot and / or mini-slot and / or partial time slot where some HARQ-ACK feedback is expected), wherein the first time slot or mini-slot or partial time slot is limited to the first L time slots and / or mini-slots and / or partial time slots of the burst. In one sub-example, L>=1 may be a fixed value or a configurable value. In one sub-example, one or more UEs may be scheduled for the determined time slot / mini-slot partial time slot.

[0162] In one example of a determined set of time slots and / or mini-time slots, the determined set of time slots and / or mini-time slots and / or partial time slots can be the first K>=1 time slots and / or mini-time slots and / or partial time slots (sorted by time domain position) of a determined previous DL transmission burst for unicast PDSCH transmission of one or more UEs scheduled in the burst.

[0163] Fig.12 An illustration of this example is provided where K=2.

[0164] Fig.12 Yet another exemplary set of time slots / mini-slots / partial time slots 1200 is shown in accordance with an embodiment of the present disclosure. Fig.12 The embodiment of the time slot / mini-time slot / partial time slot set 1200 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.12 The scope of the present disclosure is not limited.

[0165] In a sub-example, this example may be generalized as follows: the determined set of time slots and / or mini-slots and / or partial time slots may be the first K time slots and / or mini-slots and / or partial time slots (sorted by time domain position) of a determined previous DL transmission burst, where some HARQ-ACK feedback is expected.

[0166] In a sub-example, for example, when a non-unicast channel / signal (such as DRS) is time-domain multiplexed with the PDSCH of a determined previous DL transmission burst, the determined time slot / mini-slot / partial time slot does not have to be the first K time slots / mini-slot partial time slots of the determined previous DL transmission burst, and can be potentially non-contiguous K time slots / mini-slots / partial time slots in the time domain.

[0167] In another sub-example, the determined set of time slots and / or mini-slots and / or partial time slots may be considered to start from the determined previous DL transmission burst until the end of the first K>=1 time slots and / or mini-slots and / or partial time slots (sorted by time domain position) of the determined previous DL transmission burst including the unicast PDSCH transmission. When the CWS is adjusted based on the HARQ-ACK feedback corresponding to the unicast PDSCH transmission of the determined time slot / mini-slot / partial time slot from the DL transmission burst, this sub-example is equivalent to the previous sub-example.

[0168] In another sub-example, the determined set of slots / mini-slots / partial slots may correspond to PDSCH transmissions of one or more UEs scheduled from a determined previous DL transmission burst.

[0169] In another sub-example, the value K>=1 may be fixed or configurable and may scale with the subcarrier spacing (SCS). For example, K may be fixed to n>=1. In another instance, K may be the total number of slots / minislots / partial slots within a determined previous DL transmission burst that includes a unicast PDSCH transmission.

[0170] In another sub-example, the value of K may be dynamically changed according to some predetermined rules. In one example, K may be dynamically changed according to the number of HARQ-ACK feedbacks that the gNB performs CW timing reception or expects to receive, wherein K may be dynamically changed to a value that causes the gNB to perform CW timing reception or expects to receive at least τ2 HARQ-ACK feedbacks.

[0171] In another example, K may be dynamically changed based on the number of UEs to which the HARQ-ACK feedback to which the gNB performs CW timing reception or is expected to be received belongs to the determined previous DL transmission burst scheduling, wherein K may be dynamically changed to a value such that the gNB performs CW adjustment timing reception or is expected to receive HARQ-ACK feedback of at least τ3 UEs to which the determined previous DL transmission burst scheduling belongs. In yet another example, K may be dynamically selected as the number of time slots and / or mini-time slots and / or partial time slots of the determined previous DL transmission burst, which DL transmission burst includes all PDSCH transmissions of one or more UEs scheduled in the burst.

[0172] In another instance of this example, the determined time slots and / or mini-slots and / or partial time slot sets can be the first K>=1 time slots of an unpunctured PDSCH having a duration of 14 symbols; and / or mini-slots of an unpunctured PDSCH having a duration of less than 14 symbols; and / or partial time slots of a punctured PDSCH having a duration of less than or equal to 14 symbols, for unicast PDSCH transmission of a determined previous DL transmission burst.

[0173] In one example of a determined set of time slots and / or mini-slots, the determined set of time slots and / or mini-slots and / or partial time slots may be the first K time slots and / or mini-slots and / or partial time slots (ordered by time domain position) of a determined previous DL transmission burst for unicast PDSCH transmission of one or more UEs scheduled in the burst (or in regular time slots and / or mini-slots and / or partial time slots where some HARQ-ACK feedback is expected), wherein the first K time slots and / or mini-slots and / or partial time slots are confined to the first L time slots and / or mini-slots and / or partial time slots of the burst.

[0174] In a sub-example, for example, when a non-unicast channel / signal (such as DRS) is time-domain multiplexed with the PDSCH of a determined previous DL transmission burst, the determined time slot / mini-slot / partial time slot does not have to be the first K time slots / mini-slot partial time slots of the determined previous DL transmission burst, and can be potentially non-contiguous K time slots / mini-slots / partial time slots in the time domain.

[0175] In another sub-example, the determined set of time slots and / or mini-slots and / or partial time slots may be considered to start from the determined previous DL transmission burst to the end of the first K>=1 time slots and / or mini-slots and / or partial time slots (sorted by time domain position) of the determined previous DL transmission burst including the unicast PDSCH transmission. When the CWS is adjusted based on the HARQ-ACK feedback corresponding to the unicast PDSCH transmission of the determined time slot / mini-slot / partial time slot from the DL transmission burst, this sub-example is equivalent to the previous sub-example.

[0176] In another sub-example, the determined set of slots / mini-slots / partial slots may be associated with PDSCH transmissions of one or more UEs scheduled from a determined previous DL transmission burst.

[0177] In yet another sub-example, the value K>=1 may be fixed or configurable and may scale with the subcarrier spacing (SCS). For example, K may be fixed to n>=1. For example, K may be the total number of slots / mini-slots / partial slots within a determined previous DL transmission burst that includes a unicast PDSCH transmission, or equivalently, the determined set of slots / mini-slots / partial slots is the entire DL transmission burst. In another sub-example, L>=1 may be a fixed value or a configurable value. For example, L may be fixed to n>=1. In another instance, L may be the entire DL transmission burst.

[0178] In yet another sub-example, the value of K may be dynamically changed according to some predetermined rules. In one instance, K may be dynamically changed according to the number of HARQ-ACK feedbacks that the gNB performs CW timing reception or expects to receive, wherein K may be dynamically changed to a value that causes at least τ2 HARQ-ACK feedbacks to be received or expected to be received at the gNB. In another instance, K may be dynamically changed according to the number of UEs of a determined previous DL transmission burst scheduling to which the HARQ-ACK feedback that the gNB performs CW timing reception or expects to receive belongs, wherein K may be dynamically changed to a value that causes at least τ3>=1 UE of HARQ-ACK feedback of a determined previous DL transmission burst scheduling that the gNB performs CW adjusted timing reception or expects to receive. In yet another instance, K may be dynamically selected as the number of time slots and / or mini-time slots and / or partial time slots of a determined previous DL transmission burst, which previous DL transmission burst includes all PDSCH transmissions of one or more UEs scheduled in the burst.

[0179] In another instance of this example, the determined time slots and / or mini time slots and / or partial time slot sets can be the first K>=1 time slots with an undeleted PDSCH with a duration of 14 symbols; and / or mini time slots with an undeleted PDSCH with a duration less than 14 symbols; and / or partial time slots with a truncated PDSCH with a duration less than or equal to 14 symbols, for unicast PDSCH transmission of a determined previous DL transmission burst.

[0180] In one example of determined time slots and / or mini time slots and / or partial time slots, the determined time slots and / or mini time slots may be a subset of all time slots and / or mini time slots and / or partial time slots of a determined previous DL transmission burst, wherein the subset may be selected according to some predetermined rules different from the rules specified in the example of the determined set of time slots and / or mini time slots and / or partial time slots.

[0181] Fig.13 Yet another exemplary set of time slots / mini-slots / partial time slots 1300 is shown in accordance with an embodiment of the present disclosure. Fig.13 The embodiment of the time slot / mini-time slot / partial time slot set 1300 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.13 The scope of the present disclosure is not limited.

[0182] In a sub-example, the subset may be L>=1 slots / mini-slots / partial slots of the UE's PDSCH transmissions scheduled in the determined previous DL transmission burst (or in a regular slot / mini-slot / partial slot where some HARQ-ACK feedback is expected) closest to the timing at which the gNB performs CW adjustment. For example, these slots / mini-slots / partial slots may reflect the channel collision / congestion situation closest to the timing at which the gNB performs CW adjustment, especially considering the higher possibility of hidden node issues in NR-U with multi-beam operation compared to LTE-LAA. The illustration of this example when L=1 is in Fig.13 Shown in.

[0183] In one example of a determined set of time slots and / or mini-slots and / or partial time slots, the determined set of time slots and / or mini-slots and / or partial time slots of a determined previous DL transmission burst can be based on the time domain position of the expected or received HARQ-ACK feedback of the PDSCH transmission for the determined previous DL transmission burst; and may also depend on the minimum UE processing time of the UE scheduled on the transmission burst and / or the configured PDSCH to HARQ-ACK timing (e.g., K_1) of the UE scheduled on the transmission burst.

[0184] Fig.14 Yet another exemplary set of time slots / mini-slots / partial time slots 1400 is shown in accordance with an embodiment of the present disclosure. Fig.14 The embodiment of the time slot / mini-time slot / partial time slot set 1400 shown in is for illustration purposes only and may have the same or similar configuration. Fig.14 The scope of the present disclosure is not limited.

[0185] In a sub-example of a determined set of time slots and / or mini-slots and / or partial time slots, for the first M>=1 HARQ-ACK feedback units received or expected to be received (ordered by time domain position) in response to a PDSCH transmission from a determined previous DL transmission burst, the time slots and / or mini-slots and / or partial time slots set including the PDSCH transmission corresponding to these first M>=1 HARQ-ACK feedback units may be the determined set of time slots and / or mini-slots and / or partial time slots of the determined previous DL transmission burst. In addition, the HARQ-QCK feedback unit may be selected as a HARQ-ACK codebook or a UL time slot and / or mini-slot and / or partial time slot containing HARQ-ACK feedback.

[0186] Fig.14 An illustration of this sub-example when M=2 is provided, wherein UE1 and UE2 scheduled at time slot n-4 and time slot n-3 have capability 2 expected to report their HARQ-ACK feedback at time slot n-2 and time slot n-1, respectively, and UE0 scheduled at time slot n-5 has capability 1 expected to report its HARQ-ACK feedback at time slot n+2; and time slot n-4 and time slot n-3 are reference time domain and frequency domain resources for DL ​​transmission bursts according to this sub-example.

[0187] Fig.15 Yet another exemplary set of time slots / mini-slots / partial time slots 1500 is shown in accordance with an embodiment of the present disclosure. Fig.15 The time slot / mini-time slot / partial time slot set 1500 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.15 The scope of the present disclosure is not limited.

[0188] In another sub-example of a determined set of time slots and / or mini-slots and / or partial time slots, for multiple HARQ-ACK feedbacks received or expected to be received in the same time domain resources, when a determined set of time slots and / or mini-slots and / or partial time slots is selected as a determined previous DL transmission burst, the time slots and / or mini-slots and / or partial time slots corresponding to these HARQ-ACK feedbacks may be prioritized in increasing or decreasing order of their time domain positions.

[0189] Fig.15In the example of this sub-example provided in, UE1 and UE2 scheduled on time slot n-4 and time slot n-3 have capability 2 expected to report their HARQ-ACK feedback on time slot n-2, and UE0 scheduled on time slot n-5 has capability 1 expected to report its HARQ-ACK feedback on time slot n+2; and when M=1 and when time slots and / or mini time slots and / or partial time slots are selected as reference time domain and frequency domain resources in ascending order of their time domain positions and are prioritized, time slot n-3 is the reference time domain and frequency domain resource for the DL transmission burst according to this sub-example.

[0190] Given the determined timeslot and / or minislot and / or set of partial timeslots used for the previous DL transmission burst, the next design consideration is to determine how to select the determined previous DL transmission burst at the timing when the gNB performs CW adjustment in the mentioned embodiments / examples / instances.

[0191] In one example of a determined previous DL transmission burst, the determined DL transmission burst may be a most recent DL transmission burst that the gNB has transmitted before the timing at which the gNB performs CW adjustment (e.g., an NR-U time slot indexed with n).

[0192] In one example of a determined previous DL transmission burst, the determined previous DL transmission burst may be a most recent DL transmission burst for which at least some HARQ-ACK feedback corresponding to the determined timeslots and / or minislots and / or partial timeslots of the burst is expected to be available at the timing at which the gNB performs CW adjustment (e.g., an NR-U timeslot indexed n).

[0193] In one example of a determined previous DL transmission burst, the determined previous DL transmission burst may be a most recent DL transmission burst of the gNB such that at least some HARQ-ACK feedback corresponding to the determined timeslots and / or minislots and / or partial timeslots of the burst has been received at the timing (e.g., the NR-U timeslot indexed n) when the gNB performs CW adjustment.

[0194] In one example of a determined previous DL transmission burst, the determined previous DL transmission burst may be a most recent DL transmission burst for which all HARQ-ACKs corresponding to a determined timeslot and / or minislot and / or partial timeslot set of the burst are expected to be available at the timing at which the gNB performs CW adjustment (e.g., an NR-U timeslot with index n).

[0195] In one example of a determined previous DL transmission burst, the determined previous DL transmission burst may be a most recent DL transmission burst for which all HARQ-ACK feedbacks corresponding to the determined timeslots and / or minislots and / or partial timeslot sets of the burst have been received at the timing at which the gNB performs CW adjustment (e.g., the NR-U timeslot indexed n).

[0196] In one example of the determined previous DL transmission burst, the determined previous DL transmission burst may be the most recent DL transmission burst for which at least X% of HARQ-ACK feedback corresponding to the determined timeslots and / or minislots and / or partial sets of timeslots of the burst are expected to be available at the timing at which the gNB performs CW adjustment (e.g., the NR-U timeslot with index n). In one sub-example, X is predetermined in the specification. In another sub-example, X is determined by at least one of the minimum processing time capability of the UE, or the configured PDSCH to HARQ latency, or the allowed LBT type and / or priority class of the HARQ-ACK feedback transmission. In yet another sub-example, X is configured by a higher layer parameter.

[0197] In one example of the determined previous DL transmission burst, the determined previous DL transmission burst may be the most recent DL transmission burst for which at least X% of HARQ-ACK feedbacks corresponding to the determined timeslots and / or minislots and / or partial timeslot sets of the burst have been received at the timing at which the gNB performs CW adjustment (e.g., the NR-U timeslot with index n). In one sub-example, X is predetermined in the specification. In another sub-example, X is determined by at least one of the minimum processing time capability of the UE, or the configured PDSCH to HARQ latency, or the allowed LBT type and / or priority class of the HARQ-ACK feedback transmission. In yet another sub-example, X is configured by a higher layer parameter.

[0198] In one consideration of the present disclosure, a UL (including self-contained) time slot and / or mini time slot and / or partial time slot set is represented as a "reference HARQ time slot and / or mini time slot and / or partial time slot", and the UL time slot and / or mini time slot and / or partial time slot set is expected to contain HARQ-ACK feedback corresponding to the reference time domain and frequency domain resources for CW adjustment; then, in addition to the HARQ-ACK feedback corresponding to the reference time domain and frequency domain resources, additional HARQ-ACK feedback may be included in the reference HARQ time slot and / or mini time slot / partial time slot.

[0199] Fig.16 Yet another exemplary set of time slots / mini-slots / partial time slots 1600 is shown in accordance with an embodiment of the present disclosure. Fig.16The embodiment of the time slot / mini-time slot / partial time slot set 1600 shown in FIG. 1 is for illustration purposes only and may have the same or similar configuration. Fig.16 The scope of the present disclosure is not limited.

[0200] In one example of a reference HARQ slot and / or mini-slot and / or partial slot, only the HARQ-ACK feedback corresponding to the reference time and frequency domain resources received on the reference HARQ slot and / or mini-slot and / or partial slot at the timing at which the gNB performs CW adjustment may be used for CW adjustment.

[0201] In one example, Fig.16 An illustration is provided, wherein, within a determined DL transmission burst from NR-U slot n-5 to NR-U slot n-3, the K1 values ​​that the gNB sends to UE1 and are configured for slot n-5 to slot n-3 are K1=4, 3, 2, respectively, wherein K1 represents a delay from PDSCH to the corresponding HARQ-ACK in units of NR-U slots. As a result, the UE sends a HARQ-ACK codebook corresponding to the transmission of slot n-5 to slot n-3 in slot n-1. If slot n-5 (e.g., K=1) is determined as a reference time domain and frequency domain resource for CW adjustment, the gNB uses only the HARQ-ACK value for slot n-5 in CW adjustment, although HARQ-ACK values ​​for slot n-4 and slot n-3 are also available.

[0202] Fig.17 Yet another exemplary set of time slots / mini-slots / partial time slots 1700 is shown in accordance with an embodiment of the present disclosure. Fig.17 The embodiment of the time slot / mini-time slot / partial time slot set 1700 shown in is for illustration purposes only and may have the same or similar configuration. Fig.17 The scope of the present disclosure is not limited.

[0203] As another example, Fig.17 Another illustration is provided, in the determined DL transmission burst of NR-U slot n-5 to NR-U slot n-4, the gNB schedules UE1 and UE2 in different NR-U slots, and UE1 and UE2 respond to HARQ-ACK in HARQ-ACK slot n-1. If slot n-5 (e.g., K=1) is determined as the reference time domain and frequency domain resource for CW adjustment, although the HARQ-ACK value from UE2 in NR-U slot n-1 is also available, the gNB only uses the HARQ-ACK from UE1 for CW adjustment.

[0204] In one example of a reference HARQ slot and / or mini slot and / or partial slot, for HARQ-ACK feedback received in the reference HARQ slot and / or mini slot and / or partial slot at the timing when the gNB performs CW adjustment, the HARQ-ACK feedback corresponding to the reference time domain and frequency domain resources and other received HARQ-ACK feedback may be used for CW adjustment.

[0205] Fig.18 Yet another exemplary set of time slots / mini-slots / partial time slots 1800 is shown in accordance with an embodiment of the present disclosure. Fig.18 The embodiment of the time slot / mini-time slot / partial time slot set 1800 shown in is for illustration purposes only and may have the same or similar configuration. Fig.18 The scope of the present disclosure is not limited.

[0206] Fig.18 To provide an illustration of this example, the determined UL slot and / or mini-slot set is slot n-1, and the determined previous DL transmission burst is from slot n-5 to slot n-3. The gNB expects that all HARQ-ACK codebooks are available in slot n-1, and the CW is adjusted based on all HARQ-ACK values ​​in slot n-1.

[0207] In one example of a reference HARQ slot and / or mini slot and / or partial slot, for HARQ-ACK feedback received in the reference HARQ slot and / or mini slot and / or partial slot when the gNB performs CW adjustment timing, a subset of the HARQ-ACK feedback corresponding to the reference time and frequency domain resources and the remaining HARQ-ACK feedback received that can satisfy a certain constraint condition can be used for CW adjustment.

[0208] In one sub-example of a subset of the received remaining HARQ-ACK feedbacks, all of these received remaining HARQ-ACKs may be used for CW adjustment.

[0209] In another sub-example of the subset of remaining received HARQ-ACK feedback, a constraint on the remaining received HARQ-ACK feedback may be that the received HARQ-ACK feedback has not been previously used in a CW adjustment decision.

[0210] In yet another sub-example of a subset of the remaining received HARQ-ACK feedback, a constraint on the remaining received HARQ-ACK feedback may be that only ACK or NACK may be used as additional information for the current CW adjustment decision.

[0211] In another sub-example of a subset of the remaining received HARQ-ACK feedback, the constraint on the remaining received HARQ-ACK feedback may be that the received HARQ-ACK feedback corresponding to the PDSCH transmission within the first L time slots and / or mini time slots and / or partial time slots of a determined previous DL transmission burst can be used for CW adjustment.

[0212] In another sub-example of a subset of the remaining received HARQ-ACK feedback, the constraint that the remaining received HARQ-ACK feedback will be used for CW adjustment is that the received HARQ-ACK feedback corresponds to a PDSCH transmission from a UE that is scheduled for PDSCH transmission on reference time and frequency domain resources for CW adjustment.

[0213] In yet another sub-example of a subset of the remaining received HARQ-ACK feedback, a constraint on the remaining received HARQ-ACK feedback to be used for CW adjustment is that the received HARQ-ACK feedback corresponds to a PDSCH transmission on the same DL transmission burst as the reference HARQ slot and / or mini slot and / or partial slot.

[0214] In yet another sub-example of a subset of the remaining HARQ-ACK feedback received, the constraints of the previous sub-examples may be used in combination.

[0215] In LTE-LAA, since the delay from PDSCH transmission to the corresponding HARQ-ACK feedback delay is deterministic, each eNB can adjust the contention window only once based on a given reference subframe. For NR-U, due to the flexible and configurable timing (i.e., K_1) from PDSCH transmission to the corresponding HARQ-ACK feedback delay, the UE reports the potential LBT failure of HARQ-ACK and the potential HARQ-ACK enhancement. Another consideration for this method is the restriction on the gNB to use the given reference time and frequency domain resources for CW adjustment.

[0216] In one example of a restriction on using a given reference time and frequency domain resource for CW adjustment, the gNB may adjust the contention window only once based on a given set of reference time and frequency domain resources; and after the HARQ-ACK feedback corresponding to the given reference time and frequency domain resource has been used to adjust the contention window, the gNB may maintain the same contention window size until the HARQ-ACK feedback corresponding to a new set of reference time and frequency domain resources becomes available. In one instance of this example, similar to LTE-LAA, if any HARQ-ACK feedback corresponding to the given reference time and frequency domain resource has been used to adjust the contention window of a DL burst, the given reference time and frequency domain resource may not be used for CW adjustment of a subsequent DL burst.

[0217] In one example of restrictions on the use of a given reference time and frequency domain resources for CW adjustment, the gNB is allowed to adjust the contention window multiple times based on a given reference time and frequency domain resource set if different transmission bursts decide to adjust the CW size based on the same reference time and frequency domain resource set given by the previous transmission burst. Potential additional constraints may apply when using a given reference time and frequency domain resource set multiple times when adjusting the CW size.

[0218] In one sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, no additional constraints are required.

[0219] In another sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, an additional constraint on allowing the nth (n>1)th use of the given reference time and frequency domain resources to adjust the CW size is that an additional HARQ-ACK feedback (ACK / NACK / DTX) corresponding to the given set of reference time and frequency domain resources is received or expected to be received at the nth use of the CW size adjustment compared to the previous n-1 uses of the CW size adjustment.

[0220] In another sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, an additional constraint may be that each received HARQ-ACK feedback (i.e., ACK or NACK) of a transmitted TB / CBG corresponding to the given reference time and frequency domain resources can only be used at most once in the CW adjustment decision.

[0221] In one instance of this sub-example, when NR-U supports HARQ-ACK enhancement so that each HARQ-ACK feedback can have multiple transmission opportunities or can be reported in additional opportunities (for example, the UE initially fails to report HARQ-ACK through LBT, but is requested / triggered by the gNB to report in an additional opportunity), this example can be extended to each opportunity of HARQ-ACK feedback so that any HARQ-ACK feedback value (ACK / NACK / DTX) received in each HARQ-ACK feedback opportunity corresponding to a given reference time and frequency domain resources can only be used once in the CW adjustment decision.

[0222] In another instance of this example, when NR-U supports HARQ-ACK enhancement so that each HARQ-ACK feedback can have multiple transmission opportunities or can be reported in additional opportunities (for example, the UE initially enables LBT to fail to report HARQ-ACK, but is requested / triggered by the gNB to report in an additional opportunity), this example may also allow at most one of the HARQ-ACK feedbacks actually received in multiple HARQ-ACK feedback opportunities to be used in the CW adjustment procedure (corresponding to the HARQ-ACK feedback of the same transmitted TB or CBG).

[0223] In another sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, an additional constraint may be that the NR-U gNB may adjust the CW only based on HARQ-ACK feedback for given reference time and frequency domain resources that have not been previously used for CW adjustment.

[0224] In another sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, the additional constraints referred to above may be used in combination.

[0225] In another sub-example of the restriction on using given reference time and frequency domain resources for CW adjustment, when additional constraints on the given reference time and frequency domain resources that are used multiple times when adjusting the CW size are not met, or when HARQ-ACK feedback that satisfies the additional constraints on the given reference time and frequency domain resources that are used multiple times when adjusting the CW size is not available, the CW size may remain unchanged; otherwise the CW size may be adjusted.

[0226] Fig.19 Yet another exemplary set of time slots / mini-slots / partial time slots 1900 is shown in accordance with an embodiment of the present disclosure. Fig.19 The embodiment of the time slot / mini-time slot / partial time slot set 1900 shown in is for illustration purposes only and may have the same or similar configuration. Fig.19 The scope of the present disclosure is not limited.

[0227] In one example of a restriction on using a given reference time and frequency domain resources for CW adjustment, due to flexible HARQ-ACK feedback timing and potential HARQ-ACK enhancement, the gNB may adjust the contention window multiple times based on the given reference time and frequency domain resources, where different transmission bursts (e.g., DL burst 1 followed by DL burst 2) may correspond to the same reference time and frequency domain resources as the previous transmission burst (e.g., DL burst 0), and the available HARQ-ACK values ​​corresponding to the reference time and frequency domain resources at these transmission bursts (e.g., DL burst 1 followed by DL burst 2) may be different.

[0228] Fig.19 An illustration of this example is provided, where DL burst 0, DL burst 1, and DL burst 2 span from slot n-5 to slot n-3, from slot n to slot n+2, and from slot n+4 to slot n+6, respectively, and K1 represents the PDSCH to HARQ delay in number of NR-U slots. Fig.19 In the illustration, the CW adjustment for both DL burst 1 and DL burst 2 can be based on the HARQ-ACK feedback of the PDSCH transmission on DL burst 0. As a result, the gNB adjusts the contention window twice based on the reference time and frequency domain resources of DL burst 0.

[0229] Given the determination of the reference time and frequency domain resources for CW adjustment, another design consideration is to determine the HARQ-ACK feedback resources that can be used to perform CW adjustment at the timing when the gNB performs the CW adjustment action.

[0230] In one example, at the timing when the gNB performs a CW adjustment action (e.g., when the NR-U gNB starts to perform a new CAT-4 LBT process to initialize DL transmission), the CW adjustment decision made by the gNB may be based on all or a subset of the HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources used for CW adjustment, where the reference time domain and frequency domain resources may be determined, as well as potential additional HARQ-ACK values ​​under certain constraints.

[0231] In one example, the CW adjustment decision made by the gNB may be based solely on all HARQ-ACK values ​​corresponding to the reference time and frequency domain resources expected to be received at the timing when the gNB performs the CW adjustment action, where each HARQ-ACK value can be ACK, NACK, or DTX.

[0232] In one example, the CW adjustment decision made by the gNB may be based only on all HARQ-ACK values ​​corresponding to the reference time and frequency domain resources received at the timing when the gNB performs the CW adjustment action, where each HARQ-ACK value may be an ACK or a NACK. In one sub-example, for HARQ-ACK feedback corresponding to the reference time and frequency domain resources that were expected to be received but not received at the timing when the gNB adjusts the CW size, such HARQ-ACK feedback has no effect on the CW adjustment decision.

[0233] In one example, the CW adjustment decision made by the gNB may be based only on a subset of HARQ-ACK values ​​corresponding to reference time and frequency domain resources that are received or expected to be received at the time when the gNB performs the CW adjustment action but have not yet been used by the gNB to adjust the CW.

[0234] In one example, by the time the gNB performs a CW adjustment decision, HARQ-ACK feedback corresponding to reference time and frequency domain resources that are not expected to be received (i.e., delayed HARQ-ACK) may not contribute to the CW adjustment decision.

[0235] In one example, by the time the gNB performs a CW adjustment decision, HARQ-ACK feedback corresponding to reference time and frequency domain resources that are not expected to be received (e.g., delayed HARQ-ACK) may contribute to the CW adjustment decision. In a sub-example of this example, such delayed HARQ-ACK feedback may be considered as NACK in the CW adjustment decision, where the CW adjustment rule may be specified in the following embodiments. In another sub-example of this example, such delayed HARQ-ACK feedback may be considered as DTX in the CW adjustment decision, where the CW adjustment rule may be specified in the following embodiments.

[0236] In one example, when the gNB is allowed to adjust the contention window multiple times based on a given reference time domain and frequency domain resource set, the additional constraint for the given reference time domain and frequency domain resource set will be used multiple times when adjusting the CW size, and the additional constraint can be selected according to the example of limiting the use of the given reference time domain and frequency domain resource set for CW adjustment. It can be applied to other examples of selecting a subset of HARQ-ACK values ​​corresponding to the reference frequency domain resources and reference time domain resources for CW adjustment.

[0237] In one example, under certain criteria, in addition to the HARQ-ACK values ​​corresponding to the reference time and frequency domain resources, additional received HARQ-ACK values ​​may be used for the current CW adjustment decision. Otherwise, the gNB may only base the decision on all or a subset of the HARQ-ACK values ​​corresponding to the current reference time and frequency domain resources for CW adjustment.

[0238] In one sub-example, the criterion for allowing the use of additional HARQ-ACK values ​​for the current CW adjustment decision can be that the proportion of "DTX" (i.e., lost ACK or NACK) and / or delayed HARQ / ACK (i.e., HARQ-ACK has a large PDSCH to HARQ delay K1, and thus the HARQ-ACK is not received when the gNB adjusts the CW size) in the total number of HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources that are expected to be received or received at the timing of the gNB adjusting the CW is greater than or equal to a threshold X.

[0239] In another sub-example, the criterion for allowing the use of additional HARQ-ACK values ​​for the current CW adjustment decision can be that the proportion of "DTX" (i.e., lost ACK or NACK) and / or delayed HARQ / ACK (i.e., HARQ-ACK has a large PDSCH to HARQ delay K1, and thus the HARQ-ACK is not received when the gNB adjusts the CW size) in the total number of HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources is greater than or equal to a threshold X.

[0240] In another sub-example, a criterion for allowing additional HARQ-ACK values ​​to be used for the current CW adjustment decision may be that the number of additional HARQ-ACK values ​​exceeds a threshold, wherein the number of HARQ-ACK values ​​that belong to a different reference time and frequency domain resource set (compared to the current time and frequency domain resource set) but have not yet been used for the CW adjustment decision (e.g., ACK / NACK lost due to a previous LBT failure and / or delayed HARQ / ACK or cross-COT ACK / NACK) has exceeded a threshold. For example, the number of HARQ-ACK values ​​for CBG-based TBs may be counted on a per-TB basis (e.g., for the entire TB, if a HARQ-ACK for any CBG-based TB is received, it is counted as 1), or may be counted on a per-CBG basis (e.g., for each CBG-based HARQ-ACK received, it is counted as 1).

[0241] In another sub-example, a criterion for allowing the use of additional HARQ-ACK values ​​for the current CW adjustment decision may be that the proportion of the number of additional HARQ-ACK values ​​in the total number of HARQ-ACK values ​​for the reference time and frequency domain resources corresponding to the additional HARQ-ACK values ​​exceeds a certain threshold, wherein the additional HARQ-ACK values ​​are HARQ-ACK values ​​that belong to a different reference time and frequency domain resource set (compared to the current time and frequency domain resource set) but have not yet been used for the CW adjustment decision (e.g., ACK / NACK lost due to a previous LBT failure and / or delayed HARQ / ACK or cross-COT ACK / NACK). For example, the number of HARQ-ACK values ​​for CBG-based TBs may be counted on a per-TB basis (e.g., for the entire TB, if any HARQ-ACK for a CBG-based TB is received, then count as 1), or may be counted on a per-CBG basis (e.g., for each CBG-based HARQ-ACK received, count as 1).

[0242] In another sub-example, the additional HARQ-ACK value may be an actually received HARQ-ACK value (i.e., ACK or NACK) corresponding to a previous reference time and frequency domain resource associated with a DL transmission burst earlier than a determined DL transmission burst of the current reference time and frequency domain resource and received at the gNB performing CW adjustment timing. For example, such ACK / NACK may be reported by the UE via HARQ-ACK retransmission and / or cross-COT HARQ-ACK reporting.

[0243] In another sub-example, the additional HARQ-ACK value can be an actual received HARQ-ACK value (i.e., ACK or NACK) corresponding to a PDSCH transmission, where the PDSCH transmission is not from the current reference time and frequency domain resources, but from a determined DL transmission burst that is the same as the current reference time and frequency domain resources.

[0244] In another sub-example, the additional HARQ-ACK value may be an actually received HARQ-ACK value (i.e., ACK or NACK) corresponding to a reference time and frequency domain resource associated with a DL transmission burst that was sent later than a determined DL transmission burst of the current reference time and frequency domain resources but was received at the timing when the gNB performed the current CW adjustment decision.

[0245] In another sub-example, when the criteria for allowing the use of additional HARQ-ACK for CW adjustment are met, the additional HARQ-ACK value determined according to this example (e.g., according to the example / implementation / example, or according to a combination of the example / implementation / example) may be used in combination with the HARQ-ACK value corresponding to the reference time domain and frequency domain resources for CW adjustment. This sub-example may be triggered according to the X value.

[0246] Fig. 20 Yet another exemplary set of time slots / mini-time slots / partial time slots 2000 is shown in accordance with an embodiment of the present disclosure. Fig. 20 The embodiment of the time slot / mini-time slot / partial time slot set 2000 shown in is for illustration purposes only and may have the same or similar configuration. Fig. 20 The scope of the present disclosure is not limited.

[0247] like Fig. 20 As shown, for X=50%, where "DTX" accounts for 50% of the total expected HARQ-ACK values ​​corresponding to the reference time and frequency domain resources; thus, according to the sub-example selected, the HARQ-ACK feedback of the reference time and frequency domain resources, and the additional HARQ-ACK values ​​corresponding to the PDSCH transmission other than the PDSCH transmission from the current reference time and frequency domain resources are used for CW adjustment.

[0248] In one sub-example, when the criteria for allowing additional HARQ-ACK for CW adjustment are met, CW adjustment may use only the additional HARQ-ACK value determined from this example (e.g., according to the example) instead of the HARQ-ACK value corresponding to the reference time domain and frequency domain resources. This sub-example may be triggered depending on the value of X. For example, when X=1, this sub-example may be used.

[0249] Fig.21Yet another exemplary set of time slots / mini-slots / partial time slots 2100 is shown in accordance with an embodiment of the present disclosure. Fig.21 The embodiment of the time slot / mini-time slot / partial time slot set 2100 shown in is for illustration purposes only and may have the same or similar configuration. Fig.21 The scope of the present disclosure is not limited.

[0250] like Fig.21 As shown, the proportion of "DTX" in the total expected HARQ-ACK corresponding to the reference time and frequency domain resources is 100%, and X can be any value less than or equal to 1. In addition, according to the sub-example selected, CW adjustment is performed using only additional HARQ-ACK values ​​corresponding to PDSCH transmissions other than PDSCH transmissions of the current reference time and frequency domain resources.

[0251] In one sub-example, additional constraints may be applied when selecting the additional HARQ-ACK values ​​to be received for use in the CW adjustment decision. In one example, additional HARQ-ACK values ​​received at the timing of the gNB performing the current CW size adjustment decision but not used in any previous CW adjustment decision can be used for the current CW adjustment decision.

[0252] In one example, when the threshold is X=0, then additional HARQ-ACK values ​​(if any), i.e., received ACK / NACK corresponding to previous reference time and frequency domain resources and ACK / NACK values ​​not yet used for adjusting CW, may always be used for the current CW adjustment decision.

[0253] In another example, when the threshold X is a very small positive number (e.g., 1e-10), then whenever a DTX (i.e., ACK / NACK is lost) is received at a timing of performing CW adjustment at the gNB, an additional HARQ-ACK value (if any) may be used for CW adjustment, where the DTX corresponds to the reference time and frequency domain resources for CW adjustment.

[0254] In another example, when the threshold X is 1, then when all HARQ-ACK values ​​corresponding to the reference time and frequency domain resources expected to be received when the gNB adjusts the CW timing are "DTX", additional HARQ-ACK values ​​(if any) may be used for CW adjustment.

[0255] In another example, when the threshold X is greater than 1, then the additional HARQ-ACK value may never be used for CW adjustment.

[0256] In another instance, if the initial transmission of such HARQ-ACK has failed (e.g., due to LBT failure), and / or such HARQ-ACK is delayed to be reported at a later time, and such HARQ-ACK feedback is received in a later time domain instance before the current time used for the CW adjustment decision, then the additional HARQ-ACK may be used for the current CW adjustment decision.

[0257] In one example, at the timing when the gNB performs a CW adjustment action, the gNB can dynamically switch the HARQ-ACK feedback resources that can be used for CW adjustment, wherein the switching decision can be made based on the received HARQ-ACK feedback values ​​corresponding to the current reference time domain and frequency domain resources.

[0258] In a sub-example, in a scenario where the ratio of "DTX" (i.e., lost ACK or NACK) and / or delayed HARQ / ACK (i.e., HARQ-ACK with a large PDSCH to HARQ delay K1, and thus no HARQ-ACK is received at the timing when the gNB adjusts the CW size) to the total number of HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources expected to be received or received at the gNB adjusting the CW timing is greater than or equal to a certain threshold X, the CW adjustment may only use the additional HARQ-ACK values ​​determined (e.g., according to the embodiment / example / instance), and may not use the HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources.

[0259] This sub-example is equivalent to the gNB being able to dynamically change the reference time domain and frequency domain resources used for CW adjustment decisions when there are lost ACK / NACKs in the current reference time domain and frequency domain resources.

[0260] In another sub-example, in a scenario where the proportion of "DTX" (i.e., lost ACK or NACK) and / or delayed HARQ / ACK (i.e., HARQ-ACK with a large PDSCH to HARQ delay K1, and thus no HARQ-ACK is received at the timing when the gNB adjusts the CW size) in the total number of HARQ-ACK values ​​corresponding to the reference time and frequency domain resources is greater than or equal to a threshold X, the CW adjustment may only use the additional HARQ-ACK values ​​determined (e.g., according to the embodiment / example / instance), and may not use the HARQ-ACK values ​​corresponding to the reference time and frequency domain resources.

[0261] This sub-example is equivalent to the gNB being able to dynamically change the reference time domain and frequency domain resources used for CW adjustment decisions when there are lost ACK / NACKs in the current reference time domain and frequency domain resources.

[0262] In another sub-example, in a scenario where the total number of HARQ-ACK values ​​corresponding to the reference time domain and frequency domain resources expected to be received when the gNB adjusts the CW timing is less than a threshold X, the CW may only use the HARQ-ACK value corresponding to the current reference time domain and frequency domain resources, which may be determined according to the implementation / example / instance.

[0263] In another sub-example, in the following scenario, CW adjustment may only use additional HARQ-ACK values ​​determined according to the embodiment / example / instance and may not use HARQ-ACK values ​​corresponding to reference time domain and frequency domain resources: the number of additional HARQ-ACK values ​​has exceeded a certain threshold, wherein the additional HARQ-ACK values ​​are HARQ-ACK values ​​that belong to different sets of reference time resources and reference frequency resources (compared with the current reference time resources and reference frequency resources) but have not yet been used for the CW adjustment decision (for example, ACK / NACK lost due to previous LBT failure, and / or delayed HARQ / ACK, or cross-COT ACK / NACK).

[0264] For example, the number of HARQ-ACK values ​​for CBG-based TBs may be counted on a per-TB basis (e.g., for the entire TB, if any HARQ-ACK for CBG-based TBs is received, then count as 1), or may be counted on a per-CBG basis (e.g., for each CBG-based HARQ-ACK received, count as 1). This sub-example may be equivalent to, when there is ACK / NACK for a reference time domain and frequency domain resource different from the current reference time domain and frequency domain resource and such ACK / NACK has not been used in adjusting the CWS, the gNB is able to dynamically change the reference time domain and frequency domain resources for CW adjustment decision.

[0265] In another sub-example, in the following scenario, CW adjustment may only use additional HARQ-ACK values ​​determined according to the embodiment / example / instance and may not use HARQ-ACK values ​​corresponding to reference time domain and frequency domain resources: the ratio of the number of additional HARQ-ACK values ​​to the total number of HARQ-ACK values ​​of the reference time domain and frequency domain resource set (corresponding to the additional HARQ-ACK values) exceeds a certain threshold, wherein the additional HARQ-ACK values ​​belong to different reference time resources and reference frequency resource sets (compared with the current reference time resources and reference frequency resources) but have not yet been used for CW adjustment decisions (for example, ACK / NACK lost due to previous LBT failure, and / or delayed HARQ / ACK, or cross-COT ACK / NACK).

[0266] For example, the number of HARQ-ACK values ​​for CBG-based TBs may be counted on a per-TB basis (e.g., for the entire TB, if any HARQ-ACK for CBG-based TBs is received, then count as 1), or may be counted on a per-CBG basis (e.g., for each CBG-based HARQ-ACK received, count as 1). This sub-example may be equivalent to, when there is ACK / NACK for a reference time domain and frequency domain resource different from the current reference time domain and frequency domain resource and such ACK / NACK has not been used in adjusting the CWS, the gNB is able to dynamically change the reference time domain and frequency domain resources for CW adjustment decision.

[0267] In one example, the determined HARQ-ACK feedback resources may be used for CW adjustment at the timing when the gNB performs the CW adjustment action.

[0268] Given the determined reference time and frequency domain resources for CW adjustment and the determined timing at which the gNB can perform the CW adjustment action, another design consideration is the timing at which the gNB can perform the CW adjustment action.

[0269] The gNB may perform a reference timing for CW adjustment actions, which may be the same as the reference timing for LTE-LAA, before the gNB generates a random backoff counter for performing a new CAT-4 LBT procedure to initialize DL transmission. At the reference timing, the gNB may determine and collect HARQ-ACK feedback that may be used for CWS adjustment decisions, and perform CWS adjustment decisions according to an embodiment / example / instance.

[0270] Due to the flexible PDSCH to HARQ-ACK delay and potential HARQ-ACK enhancement for NR-U, the NR-U gNB may receive ACK / NACK feedback reported from a different carrier or the same carrier as the gNB during the CAT-4 LBT procedure. As a result, NR-U can support additional time for the gNB to perform CW adjustment actions compared to the reference timing.

[0271] In one example, in addition to supporting CW adjustment before the gNB generates a random backoff counter for a new CAT-4 LBT procedure to initialize DL transmission, additional CW adjustment timing for NR-U may be supported during the CAT-4 LBT procedure when certain conditions are met.

[0272] In one example, it may be allowed to perform CW adjustment only before the gNB generates a random backoff counter for performing a CAT-4 LBT procedure to initialize DL transmission; and the ACK / NACK feedback received during the current CAT-4 LBT procedure may be potentially used for CW adjustment decision before the next CAT-4 LBT procedure.

[0273] In one example, a condition for allowing additional CW adjustment timing may be that an additional ACK / NACK value is received during the CAT-4 LBT procedure after the most recent reference timing at which CW adjustment was made (eg, during the CAT-4 LBT procedure).

[0274] In one example, the conditions for allowing additional CW adjustment timing may be: receiving an additional ACK / NACK value after the most recent reference timing for making CW adjustment; and maintaining the CW size for making CW adjustment decisions (e.g., due to lost ACK / NACK or reaching a maximum CW size) before the gNB generates a random backoff counter for the current CAT-4 LBT procedure.

[0275] In one example, the conditions for allowing additional CW adjustment timing may be: receiving an additional ACK / NACK value during the CAT-4 LBT process after the most recent reference timing for making CW adjustment (e.g., during a CAT-4 LBT process); and increasing the CW size to make a CW adjustment decision before the gNB generates a random backoff counter for the current CAT-4 LBT process.

[0276] In one example, the conditions for allowing additional CW adjustment timing may be: after the most recent reference timing for CW adjustment (e.g., during a CAT-4 LBT process), additional ACK / NACK values ​​are received during a CAT-4 LBT process; in the HARQ-ACK feedback expected to be received by the gNB adjusting the CW timing corresponding to the reference time and frequency domain resources used in updating the CW size for the current LBT process and before the gNB generates a random backoff counter for the current CAT-4 LBT process, the proportion of received DTX in all expected HARQ-ACK feedback exceeds a certain threshold X. For example, when X=1, it means that no new HARQ-ACK information is available when the CW size is updated at the beginning of the CAT-4 LBT process.

[0277] In one example that may be used in combination with the described examples / implementations / examples, the conditions for allowing additional CW adjustment timing may be that the number of additional ACK / NACK bits received after the most recent reference timing of the CW adjustment (e.g., during a CAT-4 LBT process) exceeds a certain threshold T, and / or the number of scheduled UEs corresponding to these additionally received ACK / NACK bits exceeds another threshold N.

[0278] In a sub-example, during the current CAT-4 LBT process the gNB may receive ACK / NACK values ​​at multiple time domain locations when the number of accumulated ACK / NACK values ​​exceeds a threshold T and / or the number of scheduled UEs corresponding to these ACK / NACK values ​​exceeds a threshold N.

[0279] Fig. 22 Yet another exemplary set of time slots / mini-time slots / partial time slots 2200 according to an embodiment of the disclosure is shown. Fig. 22 The implementation of the time slot / mini-time slot / partial time slot set 2200 shown in is for illustration purposes only and may have the same or similar configuration. Fig. 22 The scope of the present disclosure is not limited.

[0280] In one example, additional ACK / NACK values ​​corresponding to the reference time domain and frequency domain resources used in the CW adjustment of the current CAT-4 LBT process, received after the most recent reference timing for CW adjustment (e.g., during a CAT-4 LBT process), may be used for additional CW adjustment of the present method.

[0281] like Fig. 22 As shown, in the examples, if the corresponding conditions for each example are met, the CW can be adjusted based on the ACK / NACK from UE1 during the ongoing CAT-4 LBT procedure.

[0282] Fig.23 Yet another exemplary set of time slots / mini-slots / partial time slots 2300 is shown in accordance with an embodiment of the present disclosure. Fig.23 The implementation of the time slot / mini-time slot / partial time slot set 2300 shown in is for illustration purposes only and may have the same or similar configuration. Fig.23 The scope of the present disclosure is not limited.

[0283] In one example, an additional ACK / NACK value is received after the most recent reference timing of the CW adjustment (e.g., during a CAT-4 LBT process) and can be used for additional CW adjustment of the present method, wherein the additional ACK / NACK value corresponds to a new reference time domain resource and a reference frequency domain resource, and the determined DL transmission burst corresponding to the additional ACK / NACK value is later than the DL transmission burst of the reference time domain and frequency domain resources used during adjustment of the CW of the current CAT-4 LBT process.

[0284] like Fig.23As shown, for the current CAT-4 LBT process starting from time slot n+2, the CW size for initiating CAT-4 LBT is based on the HARQ-ACK feedback corresponding to the DL bursts from time slot n-5 to time slot n-3; and the additional ACK / NACK value corresponding to the DL bursts from time slot n-1 to time slot n is received during the current CAT-4 LBT process. In the examples, if the corresponding conditions of each example are met, the CW can be adjusted based on the ACK / NACK received during the ongoing CAT-4 LBT process.

[0285] In one example, additional ACK / NACK values ​​received after the most recent reference timing of the CW adjustment (e.g., during a CAT-4 LBT process) and corresponding to reference time and frequency domain resources may be used for additional CW adjustments of the present method, where the determined DL transmission burst corresponding to the reference time and frequency domain resources is earlier than the DL transmission burst of the reference time and frequency domain resources used during adjustment of the current CAT-4 LBT process.

[0286] In one example, an example may be used in combination with one or more of the described examples / examples / implementations.

[0287] In one example, the CW may be adjusted based on a minimum UE processing time (eg, HARQ processing time) for the UE invoked on the reference time and frequency domain resources and its corresponding UE functionality.

[0288] In one sub-example, when a single UE is scheduled on reference time and frequency domain resources, the CW may remain unchanged within a minimum UE processing time and the CW may be allowed to be updated outside of the minimum processing timing.

[0289] In another sub-example, when multiple UEs are scheduled on reference time domain and frequency domain resources, the UE minimum processing time of the reference time domain and frequency domain resources can be determined as the maximum value of the UE minimum processing time of each UE scheduled on the reference time domain and frequency domain resources; the CW can remain unchanged within the minimum UE processing timing of the reference time domain and frequency domain resources, and the CW is allowed to be updated outside the UE minimum processing time of the reference time domain and frequency domain resources.

[0290] In another sub-example, when multiple UEs are scheduled on reference time domain and frequency domain resources, the UE minimum processing time of the reference time domain and frequency domain resources can be determined as the minimum value of the UE minimum processing time of each UE scheduled on the reference time domain and frequency domain resources; the CW can remain unchanged within the minimum UE processing time of the reference time domain and frequency domain resources, and the CW is allowed to be updated outside the UE minimum processing time of the reference time domain and frequency domain resources.

[0291] In yet another sub-example, an example may be used in combination with the described implementation / example / example.

[0292] In one example, the CW may be adjusted based on a configured PDSCH-to-HARQ delay (ie, K1) value for a UE scheduled on reference time and frequency domain resources.

[0293] In one sub-example, when a single UE is scheduled on reference time and frequency domain resources, the CW may remain unchanged within the configured K1 of the UE and CW updates may be allowed outside the configured K1 for the UE.

[0294] In another sub-example, when multiple UEs are scheduled on reference time domain and frequency domain resources, K1 configured for the reference time domain and frequency domain resources can be determined as the maximum value of K1 configured for each UE scheduled on the reference time domain and frequency domain resources; CW can remain unchanged within K1 configured for the reference time domain and frequency domain resources, and CW update is allowed outside K1 configured for the reference time domain and frequency domain resources.

[0295] In another sub-example, when multiple UEs are scheduled on reference time domain and frequency domain resources, K1 configured for the reference time domain and frequency domain resources can be determined as the minimum value of K1 configured for each UE scheduled on the reference time domain and frequency domain resources; CW can remain unchanged within K1 configured for the reference time domain and frequency domain resources, and CW update is allowed outside K1 configured for the reference time domain and frequency domain resources.

[0296] In one example, in addition to the reference CW adjustment timing, the CW may be adjusted when the proportion of HARQ-ACK feedback (i.e., ACK or NACK) actually received for a reference time and frequency domain resource after the most recent reference timing for which CW adjustment was performed (e.g., during a CAT-4 LBT process) exceeds a threshold Y% of the total number of expected HARQ-ACK values ​​corresponding to the reference time and frequency domain resource for the most recent CW adjustment reference timing.

[0297] In one example, there may be a constraint on the maximum number of CW adjustment timings allowed during a CAT-4 LBT procedure. For example, the constraint may be that a maximum of 1 CW adjustment timing is allowed during an ongoing CAT-4 LBT procedure.

[0298] Based on the determination of the time and reference time and frequency domain resources for CW adjustment, and the determination of the corresponding HARQ-ACK feedback resources that can be used for CW adjustment, the actual CW adjustment rules are formulated in the next embodiment.

[0299] In one embodiment, a contention window adjustment rule based on received HARQ-ACK feedback is provided.

[0300] In this embodiment, methods and examples are provided for CWS adaptation rules of the gNB based on the HARQ-ACK feedback determined according to the described embodiment.

[0301] In addition, the gNB may perform parallel LBT on multiple frequency units within its wideband carrier, and multiple CWSs are maintained by the gNB, where each CWS is maintained to correspond to HARQ-ACK feedback on a different set of frequency units. In this case, the CWS adaptation rules in this example can be applied independently to each of such CWSs, where each CWS is maintained on the set of frequency units that the CWS depends on based on the HARQ-ACK feedback determined from the described embodiment.

[0302] When the gNB performs CW adjustment timing (e.g., in NR-U time slot n), the gNB may collect the HARQ-ACK feedback resource set determined from Embodiment 1 for the current CW adjustment decision, which may be expressed as H = {HARQ 1 , ..., HARQ m}, where HARQ_ i (1<=i<=m) represents the HARQ-ACK feedback corresponding to the transport block (TB) sent to the scheduled UE, the transport block (TB) is a set of HARQ-ACK information bits, and its size is 1 when TB-based HARQ-ACK feedback is used; when CBG-based HARQ-ACK feedback is used, the size of HARQ_i (1<=i<=m) is greater than 1. The value of each element of HARQ_i (1<=i<=m) may correspond to ACK, NACK, or DTX (i.e., ACK or NACK is not received).

[0303] In an example of a HARQ-ACK feedback set H, when the (re)transmitted TB is based on a CBG, the corresponding set HARQ_i (1<=i<=m) may contain only the ACK / NACK bits for the CBG actually transmitted (for example, determined by the CBG transmission information (CBGTI) in the DCI being equal to 1), while the HARQ-ACK in the CBG when CBGTI=0 may be ignored, since these HARQ-ACK information bits are useful for determining whether the TB is successfully transmitted.

[0304] In one example of HARQ-ACK feedback set H, when the (re)transmitted TB is based on CBG, the corresponding set HARQ_i (1<=i<=m) may contain the ACK / NACK bits of the actually transmitted CBGs (e.g., determined by the CBG transmission information (CBGTI) in the DCI being equal to 1), while the HARQ-ACK in the CBGs when CBGTI=0 may be regarded as received ACK, since these CBGs are not scheduled by the gNB for retransmission.

[0305] In one instance, if the proportion of received NACKed TBs exceeds a certain threshold η (0<=η<1), the CW size is incremented to the next available value of the corresponding channel access priority category, otherwise the CW size is set to the minimum CW size of the corresponding channel access priority category; wherein, when the TBs are grouped into multiple CBGs, the TB can be defined as ACKed or NACKed according to predetermined rules.

[0306] In one example, the threshold ratio of NACKed TBs may be η=80%.

[0307] Before the gNB performs a CW adjustment decision, it needs to determine how the “DTX” received in the HARQ-ACK feedback resource set H can be used for CW adjustment.

[0308] In one example, for lost ACK / NACK or equivalently received DTX in each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust the CW, each DTX can be regarded as a NACK and the CW adjustment rules specified in the example / instance / implementation can be used.

[0309] In one example, for each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust the CW, each DTX cannot be counted, and thus each DTX has no effect on the CW adjustment rules specified in the example / instance / implementation.

[0310] In addition, DTX is not counted and thus it does not contribute to the CW adjustment rules, meaning that within the HARQ-ACK for CW adjustment (i.e. H = {HARQ_1, ..., HARQ_m}), the elements with the value "DTX" may be excluded from the set H used for CW adjustment decision. For example, if the i-th element of H is HARQ_i = {"DTX"}, then HARQ_i may be considered as an empty set for CW adjustment decision. The same rules apply to the rest of the embodiments / examples / examples.

[0311] In one example, for a lost ACK / NACK or equivalently received DTX in each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust the CW, the DTX is treated as a NACK or the DTX is not counted for CW adjustment, which may be configurable and / or dynamically changed when applied to the CW adjustment rules specified in the embodiment / example / instance. In a sub-example, this may depend on whether HARQ-ACK enhancement is supported so that a lost ACK / NACK (i.e., DTX) may be triggered (by the gNB or UE) to be reported in a later COT or have the opportunity to be reported in other time / frequency domain resources; wherein, if such enhancement is supported, the lost ACK / NACK cannot be counted for CW adjustment, otherwise the lost ACK / NACK may be treated as a NACK.

[0312] After the gNB has determined how to handle missed ACK / NACK (i.e., DTX) for CW adjustment decision, the actual CW adjustment rules may be as follows.

[0313] In one example, the predetermined rule for determining whether a CBG-based TB may be ACKed or NACKed may be based on the rule of the HARQ-ACK feedback set used for the TB, and the proportion of CBGs that are ACKed is represented by HARQ_i (1<=i<=m); wherein, if the ratio of the number of CBGs that are NACKed to the number of HARQ-ACK bits of HARQ_i (i.e., the base) is greater than a threshold δ, where 0<δ<1, then the TB based on the CBG is NACKed.

[0314] In one sub-example, the actual transmitted CBG of the TB may be determined from the DCI parameter CBG transmission information (CBGTI). In another sub-example, the threshold δ may be 0, which means that the TB is NACKed as long as any one of the transmitted CBGs is NACKed. In another sub-example, the threshold δ may be less than 1 but very close to 1, such as 0.99999, so that the TB is NACKed only when all transmitted CBGs are NACKed, or equivalently, the TB is ACKed if any CBG is ACKed.

[0315] In one example, the predetermined rule for determining whether a CBG-based TB may be ACKed or NACKed may be based on the ACK / NACK information of the reference CBG determined in the CBG actually transmitted by the TB.

[0316] In one sub-example, the reference CBG may be the first K>=1 CBGs among the CBGs actually sent by the TB, and the first K>=1 CBGs are sent earlier than the remaining CBGs among the CBGs actually sent by the TB. In another sub-example, if (the number of reference CBGs NACKed / the total number of reference CBGs of the TB) is greater than a threshold δ, where 0<δ<1, the CBG-based TB is NACKed. In one instance of this sub-example, the threshold δ may be 0, which means that the TB is NACKed as long as any one of the reference CBGs is NACKed. In one instance of this sub-example, the threshold δ may be less than 1 but very close to 1, such as 0.99999, so that the TB is NACKed only when all reference CBGs are NACKed, or equivalently, the TB is ACKed if any reference CBG is ACKed.

[0317] In one example, at the timing when the gNB performs CW adjustment (e.g., at NR-U slot n), the HARQ-ACK feedback resources used by the gNB for the current CW adjustment decision are determined and collected according to the examples / instances / implementations. In a sub-example, the TBs received in this method that are NACKed are calculated in the selected HARQ-ACK feedback resources that can be used for the current CW adjustment decision.

[0318] In one example, if the gNB receives 1 ,...,HARQ m}If the weighted average proportion of received NACK bits exceeds a certain threshold η (0<=η<1), the size of the CW is incremented to the next available value of the corresponding channel access priority category, otherwise the CW size is set to the minimum CW size of the corresponding channel access priority category; wherein, when the TB is grouped into multiple CBGs, the HARQ-ACK bits for each CBG can be processed independently when determining the weighted average proportion of NACK (when configured).

[0319] In one example, if after the gNB has determined how to handle missed ACK / NACKs (i.e., DTX) for CW adjustment decisions by updating H, the following conditions for the weighted average proportion of NACK bits are met, then CWS is increased to the next available value:

[0320]

[0321] in, is the jth ACK / NACK bit of HARQ_i (1<=i<=m) The corresponding weight; and if If it is NACK, otherwise

[0322] In one example, CWS is increased to the next available value if the following conditions for the weighted average proportion of NACK bits are met after the gNB has determined how to handle missed ACK / NACKs (i.e., DTX) for CW adjustment decisions by updating H:

[0323]

[0324] in, is the jth ACK / NACK bit of HARQ_i (1<=i<=m) The corresponding weight; and if If it is NACK, otherwise

[0325] Before the gNB performs a CW adjustment decision, the gNB needs to determine how the “DTX” received in the HARQ-ACK feedback resource set H can be used for CW adjustment.

[0326] In one example, for lost ACK / NACK or equivalent received DTX in each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust CW, each DTX can be regarded as NACK, and the CW adjustment rules specified in the example / instance / implementation.

[0327] In one example, for each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust the CW, the lost ACK / NACK or equivalent received DTX cannot be counted, so each DTX does not work for the CW adjustment rule specified in the example / instance / implementation. In addition, DTX is not counted and thus it does not work for the CW adjustment rule, which means that in the HARQ-ACK feedback resource set used for CW adjustment (i.e., H={HARQ 1 ,...,HARQ m}), elements with the value "DTX" may be excluded from the set H used for CW adjustment decision. For example, if the i-th element of H is HARQ_i={"DTX"}, then HARQ_i may be regarded as an empty set for CW adjustment decision, as described in detail in the embodiments / examples / examples.

[0328] In one example, for lost ACK / NACK or equivalently received DTX in each HARQ-ACK resource set HARQ_i (1<=i<=m) that can be used to adjust the CW, the DTX is treated as a NACK or the DTX is not counted for CW adjustment, which can be configurable and / or dynamically changed when applied to the CW adjustment rules specified in the embodiment / example / instance.

[0329] In one sub-example, it may depend on whether HARQ-ACK enhancement is supported such that a lost ACK / NACK (i.e., DTX) may be triggered (by the gNB or UE) to be reported in a later COT, or have multiple opportunities to report such as in other time / frequency resources; wherein, if such enhancement is supported, the lost ACK / NACK is not counted for CW adjustment, otherwise the lost ACK / NACK may be considered as a NACK.

[0330] After the gNB has determined how to handle missed ACK / NACK (i.e., DTX) for CW adjustment decision, the actual CW adjustment rules may be as follows.

[0331] In one example, the weight may be equal for each HARQ-ACK bit, regardless of whether the HARQ-ACK bit corresponds to a TB or the HARQ-ACK bit corresponds to a CBG. This means In a sub-example, the embodiments / examples / cases may be applicable to each other or applied in combination with the embodiments / examples / cases.

[0332] In one example, for a CBG-based TB, the weight of each CBG may be proportional to the number of CBGs actually sent by the TB.

[0333] In a sub-example, if |HARQ i |≠0 otherwise Wherein, as described in detail in the example, base|HARQ i |“DTX” has been considered to be potentially excluded. This sub-example means that for a CBG-based TB, the HARQ-ACK bits for each CBG of the TB are evenly divided among the multiple CBGs actually transmitted in the TB.

[0334] In another sub-example, the embodiments / examples / cases described above may be applicable to each other or applied in combination with the embodiments / examples / cases described above.

[0335] In one example, the threshold ratio η of the weighted average ratio of NACKs may be 80%.

[0336] In one example, at the timing when the gNB performs CW adjustment (e.g., at NR-U slot n), the HARQ-ACK feedback resources used by the gNB for the current CW adjustment decision are determined and collected according to the embodiments / examples / instances. In one sub-example, the TBs received in the method that are NACKed are calculated in the selected HARQ-ACK feedback resources that can be used for the current CW adjustment decision.

[0337] In one example, depending on the HARQ-ACK feedback resource set used for the current CW adjustment decision (ie, H = {HARQ 1 , ..., HARQ m}) in the “DTX” receive state; in addition to allowing the CW size to be increased to the next available value of the corresponding channel access priority category or reset to the minimum value of the corresponding channel access priority category, the CW size is also allowed to remain unchanged.

[0338] In one example, if the weighted average proportion of "DTX" in the HARQ-ACK set (ie, set H) used for the current CW adjustment decision exceeds a certain threshold τ, the CW size may be maintained.

[0339] In a subexample, this means that if If If it is 'DTX' otherwise The CW size can be maintained.

[0340] In another sub-example, this means that if If If it is 'DTX' otherwise Otherwise the CW size can be maintained.

[0341] In one example, if the proportion of TBs received with DTX in the TBs in the HARQ-ACK feedback resource set used for the current CW adjustment decision exceeds a certain threshold η (0<=η<1), the CW size may be maintained.

[0342] In a sub-example, when a TB is grouped into multiple CBGs, the TB may be considered as DTX if the proportion of CBGs of the TB that are DTX exceeds another threshold η2 (0<=η2<1) or all CBGs of the TB are DTX.

[0343] In another sub-example, when a TB is grouped into multiple CBGs, if the reference CBG of the TB is DTX, the TB may be considered as DTX. For example, the reference CBG may be the first CBG of the TB.

[0344] In another sub-example, when a TB is grouped into multiple CBGs, if multiple reference CBGs are selected and the proportion of CBGs in the reference CBGs that are DTX exceeds a certain threshold η, the TB may be considered DTX. For example, the multiple reference CBGs may be selected as the first two CBGs, and the threshold may be selected as 49.999%.

[0345] In one example, allowing the CW to remain unchanged may be used when the UE is subject to LBT when sending HARQ-ACK feedback.

[0346] In one example, if the conditions allowing the CW to remain unchanged are not met, the CW may be adjusted according to any of the described embodiments / examples / cases.

[0347] In one example, at the timing when the gNB performs CW adjustment (e.g., at NR-U slot n), the HARQ-ACK feedback resources used by the gNB for the current CW adjustment decision are determined and collected according to the embodiments / examples / instances. In one sub-example, the TBs received in the method that are NACKed are calculated in the selected HARQ-ACK feedback resources that can be used for the current CW adjustment decision.

[0348] In one example, as described in detail in the described embodiments / examples / instances, if CW adjustments are supported after the most recent reference timing for CW adjustments (e.g., during a CAT-4 LBT process), additional enhancements may be allowed to update the CW size and / or backoff counter for an ongoing CAT-4 LBT.

[0349] In one example, for a CW adjustment action after the most recent reference timing of CW adjustment (e.g., during a CAT-4 LBT procedure), if a determination is made to increment the CW size according to the embodiment / example / instance described, then if a decision to increment the current CW size has not been made by CW adjustment at the start of the ongoing CAT-4 LBT procedure, the gNB may increment the CW size to the next available value.

[0350] In one sub-example, a new backoff counter may be generated based on the newly incremented CW size, the new backoff counter may be evenly distributed between 0 and the new CW size, and may replace the current backoff counter. In another sub-example, a new backoff counter may be generated based on the newly incremented CW size, evenly distributed between 0 and the new CW size, and the number of backoff slots that have been counted down for the ongoing CAT-4 LBT process may be subtracted. For example, the new backoff counter may be max(N1-N2,0), where N1 is evenly distributed between 0 and the new CW size, and N2 is the number of backoff slots that have been counted down for the ongoing CAT-4 LBT process.

[0351] In one example, for a CW adjustment action after the most recent reference timing of CW adjustment (e.g., during a CAT-4 LBT process), if it is determined according to the embodiment / example / instance that the CW size is reset to the minimum CW size, the gNB may reset the CW size accordingly, and the gNB may regenerate a temporary backoff counter according to the minimum CW size. In a certain scenario, the backoff counter may replace the current backoff counter. For example, if the newly generated temporary backoff counter is less than the current backoff counter, the newly generated backoff counter may replace the current backoff counter and resume the CAT-4 LBT process; otherwise, the CAT-4 LBT process may reuse the current backoff counter.

[0352] In one embodiment, CWS adaptation for LBT of NR-U on wideband carrier is provided. In this embodiment, NR-U CWS adaptation rules are described in detail when the gNB performs multiple parallel LBT operations on a wideband NR-U carrier.

[0353] When the NR-U gNB operates on a wideband carrier, multiple parallel LBT operations can be performed simultaneously on different frequency cells, allowing for more channel access opportunities. When performing multiple parallel LBTs, the multi-carrier LBT process of LTE-LAA can be used as a benchmark to apply parallel LBT on different frequency cells of NR-U.

[0354] Specifically, Type A LBT is when CAT-4 LBT is performed independently on different frequency cells, with potential self-delay to align transmissions on multiple frequency cells. In addition, Type A1 is when a backoff counter is generated independently for each frequency cell; and Type A2 is when the same counter for all carriers is used as the counter generated by the carrier with the largest CWS. In addition, Type B LBT is when CAT-4 LBT is performed on the reference frequency cell, and a single LBT with a PIFS duration is performed on other frequency cells immediately before the Cat-4 LBT is completed.

[0355] In addition, type B1 is when a single CWS is used for all carriers and the CWS is updated according to HARQ-ACK across all carriers; while type B2 is when the CWS is maintained independently for each carrier. Given the type A LBT process and the type B LBT process, an important design consideration is the frequency unit in which the LBT is performed.

[0356] In one instance, called BWP-specific LBT, LBT operations are performed in parallel on different bandwidth parts (BWPs) in a carrier, and the HARQ-ACK feedback for each BWP can be TB-based or CBG-based. For example, BWP-specific LBT is applicable when the gNB configures multiple BWPs as active BWPs for different UEs, and the gNB attempts to perform BWP-specific LBT for UEs scheduled on these BWPs.

[0357] In another instance, this may apply when the gNB performs LBT on up to 4 configured BWPs of the UE, so that the gNB can increase the probability of sending to the UE, although a BWP switching indication may be required if LBT fails on the currently active DL BWP.

[0358] In one example, since LBT is always performed at least in units of BWP, both Type A LBT and Type B LBT are applicable to maintain the CWS of LBT for a specific BWP; and the CWS adaptation rule is obtained according to the described implementation.

[0359] In one example, called sub-band LBT, for NR-U, LBT operation can also be performed on a sub-band basis. For example, for sub-7GHz NR-U, a sub-band may have multiple PRBs with a fixed 20MHz or close to 20MHz bandwidth.

[0360] Although subband LBT can increase the probability that the gNB can successfully perform LBT on at least part of the bandwidth of the carrier, some design changes to the existing NR specifications are still required.

[0361] In one example, the code block allocation for TBs with subband LBT for NR-U can be enhanced from the NR specification so that code blocks can be allocated in units of LBT subbands in the frequency domain, and the frequency position of CBs can be aligned with the subband boundaries. In a sub-example, the CB allocation of TBs can be first performed in the subcarriers of the subband increase, then in the increasing order of symbols within the scheduling symbol of the current transmission time interval (TTI), and then in the increasing order of subbands within the scheduling PRB.

[0362] Fig.24 An exemplary CB map 2400 according to an embodiment of the present disclosure is shown. Fig.24 The implementation of CB mapping 2400 shown in is for illustration purposes only and may have the same or similar configuration. Fig.24 The scope of the present disclosure is not limited.

[0363] like Fig.24As shown, with subband LBT, the bandwidth for UE scheduling is 40 MHz, and CB0 and CB1 are grouped into CBG0, while CB2 and CB3 are grouped into CBG1. Fig.24 In (a), the CB mapping follows the CB mapping of the NR specification, and CBG0 and CBG1 can span the scheduling bandwidth of 40 MHz, and if any subband LBT of 20 MHz fails, CBG0 and CBG1 can be truncated and NACK can be reported.

[0364] like Fig.24 As shown in (b), the case of CB mapping is enhanced to align with the subband boundary, and in this case, CBG0 and CBG1 may occupy different 20MHz subbands, so if any subband LBT passes, CBG0 and / or CBG1 may be ACKed.

[0365] In one example, the CBG allocation for TBs may be enhanced so that the CBGs may be aligned with subband boundaries. In one sub-example, this may be achieved by the examples / implementations / examples and by appropriately selecting the number of CBGs configured for the TBs.

[0366] In one example, PDCCH or control resource set (CORESET) allocation may also be enhanced to support subband LBT, where PDCCH or CORESET may be allocated on a per-subband basis so that if only one subband or a few subbands within the scheduled bandwidth pass LBT, the UE is able to detect downlink control information. Without enhanced PDCCH allocation, CORESET is allocated on a per-BWP basis in the NR specification, so DCI may be sent with only one or a few subbands passing LBT, which may result in only partial DCI / PDCCH being sent, and the UE is affected by PDCCH reception failure.

[0367] In one example, for subband LBT, when the LBT subband bandwidth is smaller than the UE's scheduled bandwidth, CBG-based transmission and HARQ-ACK feedback may be used, or CBG-based transmission and HARQ-ACK feedback may at least be prioritized over TB-based transmission and HARQ-ACK feedback. This is because if TB-based transmission is used and the LBT subband is smaller than the UE's scheduled bandwidth, the TB may always be NACKed when LBT fails for one or more subbands within the UE's scheduled bandwidth, which offsets the benefits of subband LBT.

[0368] In a sub-example, this example can be extended to the following scenario: for sub-band LBT, when the LBT sub-band bandwidth is smaller than the BWP bandwidth for performing sub-band LBT, CBG-based transmission and HARQ-ACK feedback can be used.

[0369] In one example, for subband LBT, the NR-U gNB may also schedule UEs based only on the LBT subband, and each subband may be configured as TB-based HARQ-ACK feedback or CBG-based HARQ-ACK feedback.

[0370] In one sub-example, each UE may be scheduled on multiple LBT subbands; and when multiple scheduled subbands pass through LBT, these subbands may be aggregated and acknowledged together, such as through a dynamic or semi-static HARQ codebook, similar to the case where multiple carriers are scheduled for the UE (e.g., intra-band carrier aggregation). For example, since each scheduled subband of the UE is configured to be acknowledged as TB-based feedback or CBG-based feedback, the ACK / NACK information for each scheduled subband may be determined by the gNB for adjusting and maintaining the CWS.

[0371] In another sub-example, each UE may be scheduled on multiple LBT subbands; and when multiple scheduled subbands are through LBT, these subbands may be independently acknowledged, such as through a dynamic or semi-static HARQ-ACK codebook, similar to the case where multiple carriers are scheduled for the UE (e.g., intra-band carrier aggregation). For example, since each scheduled subband of the UE is configured to be acknowledged as TB-based feedback or CBG-based feedback, the ACK / NACK information for each scheduled subband may be determined by the gNB for adjusting and maintaining the CWS.

[0372] In one example, one or more of the following sub-examples may be applied to maintain the CWS of the sub-band LBT; using the CWS adaptation rules obtained according to the described embodiments.

[0373] In one sub-example, CAT-4 LBT is performed on each subband of the entire carrier, and the CWS of each subband is maintained independently. For example, according to the described embodiment, the CWS for the subbands of the carrier may be maintained by selecting time domain and frequency domain resources, wherein the reference time domain and frequency domain resources are a determined set of slots / mini-slots / partial slots of a previous DL transmission burst of the gNB on the current subband.

[0374] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0375] In one sub-example, CAT-4 LBT is performed on each sub-band within a configured BWP, and the CWS for each sub-band of the BWP is maintained independently.

[0376] For example, according to the described embodiment, the CWS for a subband of a carrier may be maintained by selecting reference time and frequency domain resources, wherein the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on the current subband.

[0377] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0378] In one sub-example, CAT-4 LBT is performed on a reference subband of the entire carrier, and a single LBT (e.g., with PIFS duration) is performed on other subbands of the carrier just before the CAT-4 LBT is completed; and a single CWS is maintained for all subbands of the carrier.

[0379] For example, according to the described embodiment, a single CWS for a subband of a carrier may be maintained by selecting reference time and frequency domain resources, where the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on all subbands of the carrier.

[0380] In one sub-example, CAT-4 LBT is performed on a reference subband of the entire carrier, and a single LBT (eg, with PIFS duration) is performed on other subbands of the carrier just before the CAT-4 LBT is completed; and CWS for each subband is maintained independently.

[0381] For example, according to the described embodiment, the CWS for a subband of a carrier may be maintained by selecting reference time and frequency domain resources, wherein the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on the current subband.

[0382] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0383] In one sub-example, CAT-4 LBT is performed on a reference subband of the subbands within the configured BWP, and a single LBT (e.g., with a PIFS duration) is performed on other subbands of the BWP just before the CAT-4 LBT is completed; and a single CWS is maintained for all subbands of the BWP.

[0384] For example, according to the described embodiment, the CWS of all subbands of the BWP may be maintained by selecting reference time and frequency domain resources, wherein the reference time and frequency domain resources are a determined set of time slots / mini-slots / partial time slots of a determined previous DL transmission burst of the gNB on all subbands of the BWP.

[0385] In one sub-example, a CAT-4 LBT is performed on a reference subband of the subbands within a configured BWP, and a single LBT (e.g., with a PIFS duration) is performed on other subbands of the BWP just before the CAT-4 LBT is completed; and a CWS for each subband of the BWP is maintained independently.

[0386] For example, according to the described embodiment, the CWS of the subband of the carrier can be maintained by selecting reference time domain and frequency domain resources, where the reference time domain and frequency domain resources are a determined set of time slots / mini time slots / partial time slots of a determined previous DL transmission burst of the gNB on the current subband.

[0387] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0388] In one sub-example, CAT-4 LBT is performed on each sub-band of the entire carrier, and a single CWS is maintained for all sub-bands of the carrier.

[0389] For example, according to the described embodiment, a single CWS for all subbands of a carrier may be maintained by selecting reference time and frequency domain resources, where the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on all subbands of the carrier.

[0390] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0391] In one sub-example, CAT-4 LBT is performed on each sub-band of a configured BWP, and a single CWS is maintained for all sub-bands on the BWP.

[0392] For example, according to the described embodiment, a single CWS for all subbands of a carrier may be maintained by selecting reference time and frequency domain resources, where the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on all subbands.

[0393] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0394] In one sub-example, CAT-4 LBT is performed on each subband of the entire carrier, and all subbands of the carrier may be divided into multiple groups, and a single CWS is maintained for each group of subbands of the carrier.

[0395] For example, according to the described embodiment, a single CWS for all subbands of a carrier may be maintained by selecting reference time and frequency domain resources, where the reference time and frequency domain resources are a determined set of slots / mini-slots / partial slots of a determined previous DL transmission burst of the gNB on all subbands of the carrier.

[0396] In another example, a backoff counter for each subband may be generated independently; or the same backoff counter (a counter generated by the subband with the maximum CWS) may be used for all subbands; or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0397] In one sub-example, CAT-4 LBT is performed on a reference subband of the entire carrier, and a single LBT (e.g., with a PIFS duration) is performed on other subbands of the carrier just before the CAT-4 LBT is completed; all subbands of the carrier may be divided into multiple groups, and a single CWS is maintained for each group of subbands of the carrier.

[0398] For example, according to the described embodiment, the CWS of the subband of the carrier can be maintained by selecting reference time domain and frequency domain resources, where the reference time domain and frequency domain resources are a determined set of time slots / mini time slots / partial time slots of a determined previous DL transmission burst of the gNB on the current subband.

[0399] In another example, a backoff counter for each subband or each subband group may be generated independently, or the same backoff counter (a counter generated by the subband with the largest CWS) may be used for all subbands, or the same backoff counter (a maximum backoff counter among all backoff counters generated in each subband according to the CWS corresponding to the subband) may be used for all subbands.

[0400] In another sub-example, when CWS for all subbands is maintained on a per-BWP basis according to one of the embodiments / examples / cases, the gNB implementation may be relied upon to decide the subband LBT type on different BWPs; and according to one of the sub-examples, it is not excluded that the gNB uses different subband LBT types on different BWPs. For example, the gNB may configure each BWP to use the sub-example, wherein, for each BWP, a single CWS on the subbands within the BWP is maintained.

[0401] In another sub-example, the subband LBT type on different carriers may be determined depending on the gNB implementation, and it is not excluded that the gNB uses different subband LBT types on different carriers according to one of the described embodiments / examples / instances.

[0402] In one example, if the PDSCH scheduled by the UE spans multiple subbands, for the subbands overlapping with the TB of the scheduled PDSCH (when the TB-based HARQ-ACK is configured for the scheduled PDSCH configuration) or the CBG (when the CBG-based HARQ-ACK is configured for the scheduled PDSCH configuration), the HARQ-ACK corresponding to the TB or CBG can be used to maintain and update the CWS corresponding to the subband.

[0403] In one embodiment, a dynamic threshold based CW adjustment is provided. In such an embodiment, the contention window size may be adjusted based on a dynamic threshold rule for HARQ feedback values ​​corresponding to a selected set of reference time and frequency domain resources, wherein the selection of reference time and frequency domain resources may be specified in the embodiment and the threshold rule for HARQ feedback values ​​may be specified in the embodiment.

[0404] For example, P_1 may represent a threshold (eg, a percentage) for increasing CW to the next possible value specified in the embodiment.

[0405] In another example, P_2 may be expressed as a ratio (e.g., percentage) between the number of HARQ values ​​expected to be received when performing CW adjustment timing and the total number of HARQ values ​​expected to be received among the HARQ-ACK values ​​corresponding to the selected reference time domain and frequency domain resource sets specified in the embodiment.

[0406] In a sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ-ACK value can be counted on a per-TB basis. Thus, the number of HARQ-ACKs for the TB is counted as 1, and for the entire TB, the number of HARQ-ACK values ​​for the CBG-based TB is also counted as 1.

[0407] In another sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ value may be counted on a per-CBG basis; and the HARQ-ACK value for TB-based HARQ-ACK may be counted on a per-TB basis. Thus, the number of HARQ-ACK values ​​for a TB with TB-based HARQ-ACK is counted as 1; the number of HARQ-ACK values ​​for a TB with CBG-based HARQ-ACK is the number of actual CBGs in the TB.

[0408] In another example, P_2 may be expressed as a ratio (e.g., percentage) between the actual number of HARQ values ​​(e.g., ACK / NACK) received when performing CW adjustment timing and the total number of HARQ values ​​expected to be received, among the HARQ-ACK values ​​corresponding to the selected reference time domain and frequency domain resource sets specified in the embodiment.

[0409] In a sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ-ACK value can be counted on a per-TB basis. Thus, the number of HARQ-ACKs for the TB is counted as 1, and for the entire TB, the number of HARQ-ACK values ​​for the CBG-based TB is also counted as 1.

[0410] In another sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ value may be counted on a per-CBG basis; and the HARQ-ACK value for TB-based HARQ-ACK may be counted on a per-TB basis. Thus, the number of HARQ-ACK values ​​for a TB with TB-based HARQ-ACK is counted as 1; the number of HARQ-ACK values ​​for a TB with CBG-based HARQ-ACK is the number of actual CBGs in the TB.

[0411] In another example, P_2 may represent the ratio (e.g., percentage) of the actual number of HARQ values ​​(e.g., ACK / NACK) received when performing CW adjustment timing, among the selected HARQ-ACK values ​​corresponding to the selected reference time domain and frequency domain resource sets specified in the embodiment, to the total number of HARQ values ​​expected to be received when performing CW adjustment timing.

[0412] In a sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ-ACK value can be counted on a per-TB basis. Thus, the number of HARQ-ACKs for the TB is counted as 1, and for the entire TB, the number of HARQ-ACK values ​​for the CBG-based TB is also counted as 1.

[0413] In another sub-example, when CBG-based HARQ-ACK is used for a TB, the HARQ value may be counted on a per-CBG basis; and the HARQ-ACK value for TB-based HARQ-ACK may be counted on a per-TB basis. Thus, the number of HARQ-ACK values ​​for a TB with TB-based HARQ-ACK is counted as 1; the number of HARQ-ACK values ​​for a TB with CBG-based HARQ-ACK is the number of actual CBGs in the TB.

[0414] The ratio between P_1 and P_2 may be determined using at least one of the following methods.

[0415] In one approach, P_1 and P_2 are predetermined in the specification (e.g., P_1 = 80% and P_2 = 100%), such that to perform a CW update, the gNB must wait for the last expected timeslot to receive the HARQ value corresponding to the selected reference time and frequency domain resources.

[0416] In another method, P_1 and P_2 may be dynamically determined based on the implementation of the gNB, such that when P_1 takes a smaller value, P_2 takes a correspondingly smaller value.

[0417] In one example, P_1 = P_2*c_1, where c_1 is a predetermined value, such as c_1 = 0.8. As another example, P_1 = max(P_2-c_2, 0), where c_2 is a predetermined value, such as c_2 = 0.2. As yet another example, P_1 = c_3*P_2-c_4, where c_3 and c_4 are predetermined values. As yet another example, P_1 and P_2 are selected from a predetermined table, such as Table 1 is an illustration of such a table.

[0418] Table 1. Example of dynamic determination of P_1 and P_2.

[0419] index P_2 P_1 1 100％ 80％ 2 80％ 60％ 3 60％ 40％ 4 40％ 20％ 5 ≤20％ 0％

[0420] In yet another approach, the relationship between P_1 and P_2 may be defined by a function such that P_2 does not decrease relative to P_1; wherein the function may be defined by a specification.

[0421] The Federal Communications Commission (FCC) defines unlicensed carriers to provide cost-free public access spectrum. UEs are allowed to use unlicensed carriers only if they do not cause significant interference to communications in licensed carriers and communications in unlicensed carriers are not protected from interference. For example, unlicensed carriers include industrial, scientific, and medical (ISM) carriers that can be used by IEEE 802.11 devices, and unlicensed national information infrastructure (UNII) carriers. LTE radio access technology (RAT) can be deployed on unlicensed spectrum, and LTE RAT is also called unlicensed LTE, LTE-U LAA, or licensed assisted access (LAA).

[0422] Fig.25 A flowchart 2500 of a listen-before-talk based channel access process in LAA is shown. Fig.25 The implementation of flowchart 2500 shown in FIG. 2 is for illustration purposes only and may have the same or similar configurations. Fig.25 The scope of the present disclosure is not limited.

[0423] In the LTE specification, after sensing that the channel is idle during the time slot duration of the postponement duration (112) and after the backoff counter (BO) in step 4) is 0 (114), the eNB may send a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), or an enhanced physical downlink control channel (EPDCCH) on the carrier performing LAA Scell ​​transmission. An example of such a channel access procedure is as follows Fig.25 As shown (e.g., for this type of channel access procedure, also known as Cat4 LBT).

[0424] The backoff counter is adjusted by sensing the channel during the additional time slot duration according to the following steps: the counter is set to a random number uniformly distributed between 0 and the contention window (CW) value (121), and go to step 4; if the counter is greater than 0 and the eNB chooses to decrement the counter, the counter is decremented by 1 (122); the channel is sensed during the additional time slot duration, and if the additional time slot duration is idle, go to step 4); otherwise go to step 5); if the counter is 0, stop; otherwise, go to step 2), sense the channel until a busy slot is detected during the additional deferral duration, or it is detected that all time slots of the additional deferral duration are idle; and if the channel is sensed to be idle during all time slot durations of the additional deferral duration, go to step 4); otherwise, go to step 5).

[0425] In addition, for each of the supported channel access priority classes, the eNB maintains a contention window value and adjusts the contention window before setting the backoff counter. The adjustment of the contention window value is based on the HARQ-ACK / NACK value corresponding to the PDSCH transmission in a reference subframe, where the reference subframe is the beginning of the most recent transmission made by the eNB on the carrier, and it is expected that at least some HARQ-ACK / NACK feedback in the most recent transmission is available.

[0426] In addition, in the LTE specification, the eNB may send a transmission on a carrier that includes a discovery signal but does not include a PDSCH. After sensing that the channel is idle within a sensing interval of at least 25us, if the duration of the transmission is less than 1ms, an LAA Scell ​​transmission is immediately performed on the carrier. This type of channel access procedure may also be referred to as Cat2 LBT.

[0427] In an NR scenario, the discovery signal may include signals and channels for cell acquisition and system information delivery, so that the physical broadcast channel (PBCH), as well as the PDCCH and scheduled PDSCH (such as for rest minimum system information (RMSI), other system information (OSI), or paging) may be part of the discovery signal. At the same time, multiple positions for synchronization signals and PBCH blocks (SS / PBCH blocks or SSBs) are predetermined in units of half frames, and each SSB may be quasi-colocated (QCLed) with the associated physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) of the RMSI. However, the transmission duration of the discovery signal may not always be limited to 1 ms in the time domain, and a channel access procedure may need to be defined.

[0428] In another NR scenario, PDSCH / PDCCH for SSB or RMSI / OSI / paging may be transmitted separately from DRS, and the transmission duration of PDSCH / PDCCH for SSB or RMSI / OSI / paging may not always be limited to 1 ms, and no hybrid automatic repeat request-acknowledgement / negative acknowledgement (HARQ-ACK / NACK) feedback may be available for its transmission, so channel access may need to be defined.

[0429] In yet another NR scenario, in the absence of HARQ-ACK / NACK feedback, there may also be transmission of other signals and channels on the uplink or sidelink, and channel access may also need to be defined.

[0430] The method of the present disclosure may be applicable at least to communication systems operating in accordance with LBT procedures, such as unlicensed spectrum (e.g., NR unlicensed spectrum) or shared spectrum (e.g., NR shared spectrum, or NR vehicle-to-everything communication on a sidelink).

[0431] The present disclosure focuses on a new type of contention window adjustment scheme when there is no associated HARQ-ACK / NACK available for transmission. The present disclosure provides the following aspects: application scenarios; an adjustment method for fixing / maintaining by a previous value based on sensing at a transmitter, based on reception of PRACK, based on RRM measurement, based on reception of Msg2 in a 4-step random access, based on reception of a second message in a 2-step random access, based on reception of Msg3 in a 4-step random access, based on reception of Msg4 in a 4-step random access, based on detection of a DCI format carried by a PDCCH, and based on results of a previous LBT.

[0432] The present disclosure provides several embodiments that can be used in conjunction with other embodiments or can be used in combination or can be operated as independent schemes. The methods, aspects and examples of the present disclosure may not be limited to applications in NR unlicensed spectrum (NR-U) or vehicle-to-everything (NR-V2X) communications.

[0433] In one embodiment, at least one method or at least one example of a method defined in the present disclosure may be applicable to at least one of the following scenarios.

[0434] The first scenario (eg, denoted as S1 in this disclosure) includes a transmission burst of a synchronization signal and a set of physical broadcast channel blocks (SS / PBCH blocks).

[0435] The second scenario (e.g., represented as S2 in the present disclosure) includes a transmission burst of an NR unlicensed spectrum discovery reference signal (NRU-DRS), wherein the NRU-DRS may include at least a set of SS / PBCH blocks and their associated RMSI or OSI or a set of PDCCH and / or PDSCH of at least one of paging.

[0436] The third scenario (eg, denoted as S3 in the present disclosure) includes a transmission burst of PDCCH and / or PDSCH of at least one of RMSI or OSI or paging, which is not included in the NRU-DRS.

[0437] The fourth scenario (eg, denoted as S4 in the present disclosure) includes a transmission burst of a physical random access channel (PRACH) in a 4-step random access procedure or a first step transmission in a 2-step random access procedure, wherein there is no HARQ-ACK / NACK associated with the transmission.

[0438] A fifth scenario (e.g., denoted as S5 in the present disclosure) includes a transmission burst of PUCCH and / or PUSCH, wherein there is no feedback indicating whether the transmission of PUCCH and / or PUSCH is successful. For one example, the transmission may be used for Msg3 in a 4-step random access procedure. For another example, the transmission may be the second step transmission in a 2-step random access procedure.

[0439] The sixth scenario (eg, denoted as S6 in this disclosure) includes a transmission burst of Msg2 in a 4-step random access procedure.

[0440] The seventh scenario (eg, denoted as S7 in the present disclosure) includes a transmission burst of Msg4 in a 4-step random access procedure.

[0441] An eighth scenario (eg, denoted as S8 in the present disclosure) includes a transmission burst of a sidelink signal and / or channel, wherein there is no feedback indicating whether the transmission of the sidelink signal and / or channel is successful.

[0442] A ninth scenario (eg, denoted as S9 in this disclosure) includes transmission bursts of multiplexed signals / channels from the above scenarios (eg, multiplexed S1, S2, and S3).

[0443] The tenth scenario (eg, denoted as S10 in this disclosure) includes transmission of signals / channels from all the above scenarios multiplexed with other PDSCH or PUSCH with feedback information.

[0444] In one embodiment, a contention window size (CWS) adjustment method is defined in the present disclosure, wherein the CWS is associated with an LBT process for generating a backoff counter that determines a sensing duration.

[0445] In one method, the CWS may be adjusted based on the sensing results performed at the transmitter side (e.g., gNB in ​​DL or UE in UL or SL). The exemplary application scenario of the example may be any one of the scenarios defined in the present disclosure, for example, including at least one of S1, S2, S3, S4, S5, S6, S7, S8, S9, or S10.

[0446] In one example, if the result of the sensing performed by the transmitter side is above a predetermined threshold TH_1, the CWS may be increased to a selected value. For example, the selected value may be the next larger value from a predetermined set compared to the current value of the CWS. For another example, the threshold TH_1 may be scaled proportionally to the sensing bandwidth.

[0447] In one example, if the result of the sensing performed at the transmitter side is below a predetermined threshold TH_2, the CWS may be reduced to a selected value. For example, the selected value may be the next smaller value from a predetermined set compared to the current value of the CWS. In one consideration, TH_2 may be the same as TH_1.

[0448] In one example, if the result of the sensing performed by the transmitter side is below a predetermined threshold TH_3, the CWS may be set to a selected value. For example, the selected value may be a minimum value in a predetermined set. For another example, the threshold TH_3 may be scaled proportionally to the sensing bandwidth. In one consideration, TH_3 may be the same as TH_1.

[0449] The sensing result in the example may include at least one of the following components. In one component, the sensing result may include the energy detected on the target carrier in the entire carrier bandwidth. In another component, the sensing result may include the energy detected on the bandwidth over which the associated signal / channel is transmitted. In yet another component, the sensing result may include the energy detected on the bandwidth of the bandwidth portion determined or configured for transmission of the associated signal / channel. In yet another component, the sensing result may include the ratio between the duration of time that the detected energy is above a predetermined threshold and the duration of time that the energy detection is performed.

[0450] In one example, the CWS may be fixed and no CWS adjustment is performed. The exemplary application scenario of the example may be any one of the scenarios defined in the present disclosure, for example, including at least one of S1, S2, S3, S4, S5, S6, S7, S8, or S9.

[0451] In one example, for each application scenario, there may be a fixed CWS.

[0452] In another example, there may be a fixed CWS associated with each predetermined maximum transmission duration (or maximum channel occupancy time), and some instances of this example are shown in TBALE 2 (e.g., for each associated MCOT, the CWS is determined to be the minimum of all possible CWSs for Cat4 LBT).

[0453] Table 2. Examples of fixed CWS based on maximum transmission duration

[0454] Maximum sending duration CWS 2ms 3 3ms 7 8ms or 10ms 15

[0455] In one example, the CWS may be adjusted based on receiving a PRACH transmission in an associated RO configured by the gNB. The exemplary application scenario of the example may be one of the scenarios defined in the present disclosure for receiving a DL broadcast transmission before PRACH, such as including at least one of S1, S2, S3 or a multiplex thereof (e.g., a specific scenario of S9).

[0456] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB successfully detects Msg1 from at least one of the union of configured ROs for all actually transmitted SS / PBCH blocks, the CWS may be reset to a minimum value in a predetermined set.

[0457] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO for Msg1 transmission monitored by the gNB, and if the gNB successfully detects Msg1 from at least one of the configured ROs for each actually transmitted SS / PBCH block, the CWS may be reset to a minimum value in a predetermined set.

[0458] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB cannot successfully detect any Msg1 from all configured ROs for all actually transmitted SS / PBCH blocks, the CWS may be increased to the next larger value in a predetermined set.

[0459] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB successfully detects Msg1 from at least one configured RO associated with at least one SS / PBCH block in the reference SS / PBCH block set, the CWS may be reset to a minimum value in a predetermined set.

[0460] In one sub-example, the reference SS / PBCH block may be the first SS / PBCH block actually transmitted (e.g., the SS / PBCH block actually transmitted with the smallest SS / PBCH block index). In another sub-example, the reference SS / PBCH block may be an actually transmitted SS / PBCH block included in the first time slot for transmission (e.g., may be 1 or 2 actually transmitted SS / PBCH blocks).

[0461] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB successfully detects Msg1 from at least one configured RO associated with each SS / PBCH block in the reference SS / PBCH block set, the CWS may be reset to a minimum value in a predetermined set.

[0462] In one sub-example, the reference SS / PBCH block may be the first SS / PBCH block actually transmitted (e.g., the SS / PBCH block actually transmitted with the smallest SS / PBCH block index). In another sub-example, the reference SS / PBCH block may be an actually transmitted SS / PBCH block included in the first time slot for transmission (e.g., may be 1 or 2 actually transmitted SS / PBCH blocks).

[0463] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB cannot detect any Msg1 from all configured ROs associated with the reference SS / PBCH block set, the CWS may be increased to the next larger value in the predetermined set. In one sub-example, the reference SS / PBCH block may be the first SS / PBCH block actually transmitted (e.g., the SS / PBCH block actually transmitted with the smallest SS / PBCH block index). In another sub-example, the reference SS / PBCH block may be an actually transmitted SS / PBCH block contained in the first time slot for transmission (e.g., may be 1 or 2 actually transmitted SS / PBCH blocks).

[0464] In one example, each actually transmitted SS / PBCH block may be associated with at least one RO monitored by the gNB for Msg1 transmission, and if the gNB cannot detect any Msg1 from a predetermined percentage of all configured ROs associated with a set of reference SS / PBCH blocks, the CWS may be increased to the next larger value in the predetermined set. In one sub-example, the reference SS / PBCH block may be the first actually transmitted SS / PBCH block (e.g., the actually transmitted SS / PBCH block with the smallest SS / PBCH block index). In another sub-example, the reference SS / PBCH block may be an actually transmitted SS / PBCH block contained in the first time slot for transmission (e.g., may be 1 or 2 actually transmitted SS / PBCH blocks).

[0465] In one example, the CWS may be adjusted based on an RRM measurement report received from a receiver. An exemplary application scenario of the example may be any one of the scenarios for DL ​​transmission defined in the present disclosure, for example, including at least one of S1, S2, S3, S6, S7, or S9. Another exemplary application scenario of the example may be S8, where RRM measurements are supported for sidelinks.

[0466] In one example, the CWS may be adjusted based on at least one of the SS-RSRP and / or SS-RSRQ in the measurement report. In one sub-example, the SS-RSRP and / or SS-RSRQ may correspond to the first SS / PBCH block actually transmitted. In another sub-example, the SS-RSRP and / or SS-RSRQ may correspond to the first SS / PBCH block actually transmitted that is also measured by the UE. In another sub-example, the SS-RSRP and / or SS-RSRQ may correspond to all SS / PBCH blocks actually transmitted. In yet another sub-example, the SS-RSRP and / or SS-RSRQ may correspond to all SS / PBCH blocks actually transmitted that are also measured by the UE (e.g., the intersection between the SS / PBCH blocks actually transmitted and the SS / PBCH blocks measured).

[0467] In one example, the CWS may be adjusted based on at least one of CSI-RSRP and / or CSI-RSRQ. In one sub-example, CSI-RSRP and / or CSI-RSRQ may be combined with SS-RSRP and / or SS-RSRQ to adjust the CWS.

[0468] In one example, the CWS can be adjusted based at least on RSSI and / or UE reported channel occupancy.

[0469] In one example, the CWS may be adjusted based at least on a measured quality associated with a wake-up signal (or COT indication signal) associated with a previous transmission after successful LBT using the CWS.

[0470] The CWS adjustment method in the above example may include at least one of the following components.

[0471] In one component, if the measurement quality is above a predetermined threshold TH_A, the CWS may be increased to a selected value. For example, the selected value may be the next larger value in a predetermined set compared to the current value of the CWS.

[0472] In one component, if the measurement quality is below a predetermined threshold TH_B, the CWS may be reduced to a selected value. For example, the selected value may be the next smaller value in a predetermined set compared to the current value of the CWS. In one consideration, TH_B may be the same as TH_A.

[0473] In one component, if the measurement quality is below a predetermined threshold TH_C, CWS may be set to a selected value. For example, the selected value may be a minimum value in a predetermined set. In one consideration, TH_C may be the same as TH_A.

[0474] In one example, the CWS may be adjusted based on the reception of Msg2 in a 4-step random access process. An exemplary application scenario of the method may be the transmission of Msg1 in a 4-step random access, for example, S4 defined in the present disclosure.

[0475] In one example, the CWS may be adjusted based on the reception of the second message in the 2-step random access procedure. An exemplary application scenario of the method may be the transmission of the first message in the 2-step random access procedure, for example, S4 defined in the present disclosure.

[0476] In one example, the CWS may be adjusted based on the reception of Msg3 in a 4-step random access procedure. An exemplary application scenario of the method may be the transmission of Msg2 in a 4-step random access procedure, for example, S6 defined in the present disclosure.

[0477] In one example, the CWS may be adjusted based on the reception of Msg4 in a 4-step random access procedure. An exemplary application scenario of the method may be the transmission of Msg3 in a 4-step random access procedure, for example, S5 defined in the present disclosure.

[0478] In one example, the CWS may be adjusted based on the detection of the DCI format carried in the PDCCH. An exemplary application scenario of the method may be sending Msg4 in a 4-step random access process, for example, S7 defined in the present disclosure.

[0479] In one example, the CWS may be adjusted based on the previous LBT result. An exemplary application scenario of the method may be the transmission of Msg1 in a 4-step random access process or the transmission of the first message in a 2-step random access, for example, S4 defined in the present disclosure.

[0480] For example, if all LBTs associated with the previous RO configuration period fail, the CWS may be reduced to the next available smaller value in the predetermined set (until a minimum value is reached). For another example, if all LBTs associated with the previous RO configuration period fail, the CWS may be reduced to the minimum value in the predetermined set. For another example, if the previous K consecutive LBT attempts for the RACH occasions associated with the UE fail, the CWS may be reduced to the next available smaller value in the predetermined set (until a minimum value is reached), where K may be an integer configured by a higher layer or a predetermined constant integer. For another example, if the previous K consecutive LBT attempts for the RACH occasions associated with the UE fail, the CWS may be reduced to the minimum value in the predetermined set, where K may be an integer configured by a higher layer or a predetermined constant integer.

[0481] In one example, the CWS may be maintained the same as the previous CWS value, and there is no adjusted CWS for the current transmission. The exemplary application scenario of the example may be at least one of S1, S2, S3, S4, S5, S6, S7, S8 or S9.

[0482] In one example, the CWS may be updated based on HARQ ACK / NACK feedback of a reference time-frequency domain resource set, wherein the reference time-frequency domain resource set is determined to exclude resources mapped for transmission of at least one of SS / PBCH blocks, NRU-DRS, or broadcast channels (e.g., RMSI, OSI, paging). An exemplary application scenario of the example may be at least S10.

[0483] A special case of this method is that the reference time-frequency domain resource set is an empty set (for example, used only for transmission bursts with SS / PBCH blocks, NRU-DRS, or broadcast channels (for example, RMSI, OSI, paging)), then the CWS can be maintained the same as the previous CWS value and no CWS adjustment is performed on the current transmission.

[0484] In one example, the reference time-frequency domain resource set may be the first time slot (or subframe) of the most recent transmission burst on the carrier, which contains at least one unicast PDSCH for which at least one HARQ ACK / NACK is expected to be available.

[0485] In one example, the CWS may be updated based on HARQ ACK / NACK feedback of reference time-frequency domain resources, where if X% of the HARQ ACK / NACKs corresponding to the reference time-frequency domain resource set are NACKs, the CWS is increased to the next larger value in a predetermined set.

[0486] In one example, X may be updated based on contention for the transmission. If the transmission contains only unicast signals / channels, then set X=X_1; and if the transmission contains broadcast signals / channels (e.g., at least one of SS / PBCH blocks, NRU-DRS, RMSI, OSI, paging, RAR), then set X=X_2.

[0487] In one embodiment, a method for CWS adjustment may be selected based on the RRC state of the UE. For example, the CWS may be adjusted for a UE in RRC_IDLE or RRC_INACTIVE state according to one method defined in the present disclosure, and the CWS may be adjusted for a UE in RRC_CONNECTED state according to another example defined in the present disclosure.

[0488] In one sub-example, the CWS may be adjusted for a UE in at least one of the RRC_IDLE or RRC_INACTIVE states according to the example (eg, fixed and without adjustment), and the CWS may be adjusted for a UE in the RRC_CONNECTED state according to the fourth method of the present disclosure.

[0489] In a sub-example, the CWS may be adjusted for a UE in at least one of the RRC_IDLE or RRC_INACTIVE states according to the examples, and the CWS may be adjusted for a UE in the RRC_CONNECTED state according to the examples described in the present disclosure.

[0490] In one example, the CWS may be adjusted by a network configured for a UE in an RRC_CONNECTED state according to a method defined in the present disclosure.

[0491] In one example, the backoff counter and / or LBT type may be adaptable. In one consideration, the adaptation of the backoff counter and / or LBT type may be combined with the adjustment of the CWS. In another consideration, the adaptation of the backoff counter and / or LBT type may be combined with a fixed / maintained CWS (e.g., CWS adjustment in the present disclosure).

[0492] In one example, it can be applied to exemplary application scenarios such as the transmission of Msg1 in 4-step random access or the transmission of the first message in 2-step random access (e.g., S4 defined in the present disclosure). If all LBT attempts in the previous RO configuration period fail, then for the LBT of the RO configuration period, the backoff counter can be reduced by, for example, 1 (until it reaches a minimum value in a predetermined set, such as 0). In a sub-example, the present adaptation method is only applicable when the period configured for the RO is large (e.g., greater than 10ms).

[0493] In one example, it can be applied to exemplary application scenarios such as the transmission of Msg1 in a 4-step random access or the transmission of the first message in a 2-step random access (e.g., S4 defined in the present disclosure). If the LBT associated with the previous RO fails, then for the LBT associated with the RO, the backoff counter can be reduced by, for example, 1 (until it reaches a minimum value in a predetermined set, such as 0).

[0494] In one example, it can be applied to an exemplary application scenario such as the transmission of Msg1 in a 4-step random access or the transmission of the first message in a 2-step random access (e.g., S4 defined in the present disclosure), and if all LBT attempts in the previous RO configuration period fail, then for the LBT of the RO configuration period, the backoff counter can be set to 0. In a sub-example, the present adaptation method is applicable only when the period configured for the RO is large (e.g., greater than 10ms).

[0495] In one example, it can be applied to exemplary application scenarios such as the transmission of Msg1 in a 4-step random access or the transmission of the first message in a 2-step random access (for example, S4 defined in the present disclosure), and if the LBT associated with the previous RO fails, the backoff counter for the LBT associated with the RO can be set to 0.

[0496] In one example, it can be applied to exemplary application scenarios such as the transmission of Msg1 in 4-step random access or the transmission of the first message in 2-step random access (e.g., S4 defined in the present disclosure). If all LBT attempts in the previous RO configuration period fail, then for the LBT of the RO configuration period, LBT can be applied to LBT based on single detection (e.g., CAT2LBT). This adaptation method is only applicable when the period configured for RO is large (e.g., greater than 10ms).

[0497] In one example, it can be applied to exemplary application scenarios such as the transmission of Msg1 in a 4-step random access or the transmission of the first message in a 2-step random access (e.g., S4 defined in the present disclosure). If the LBT associated with the previous RO fails, then for the LBT associated with the RO, the LBT can be applicable to a single detection-based LBT (e.g., CAT2 LBT).

[0498] Fig.26 FIG. 1 shows a method of transmitting a signal by a BS (eg, Figure 1 101-103) shown in Figure 2600 is a flowchart of method 2600 for performing multi-beam operations. Fig.26 The implementation of method 2600 shown in is for illustration purposes only and may have the same or similar configurations. Fig.26 The scope of the present disclosure is not limited.

[0499] like Fig.26 As shown, method 2600 starts from step 2602. In step 2602, the BS receives a hybrid automatic repeat request acknowledgement / negative acknowledgement (HARQ-ACK / NACK) response set from at least one user equipment (UE) via an uplink channel, the response set corresponding to a downlink transmission sent to the at least one UE.

[0500] In one embodiment, the time domain and frequency domain resource set includes at least one of a time slot set, a mini time slot set, or a partial time slot set based on a downlink transmission burst. In this embodiment, a time slot in a time slot set on an unpunctured PDSCH having a duration of 14 orthogonal frequency division multiplexing (OFDM) symbols is determined; a mini time slot in a mini time slot set on an unpunctured PDSCH having a duration less than 14 OFDM symbols is determined; and a partial time slot in a partial time slot set on a punctured PDSCH having a duration equal to or less than 14 OFDM symbols is determined.

[0501] In one embodiment, the time domain and frequency domain resource sets are determined starting from a previously transmitted downlink transmission burst until the end of the first K>=1 time slots or mini-time slots set including at least one unicast PDSCH transmission of at least one UE scheduled in the previously transmitted downlink transmission burst.

[0502] In one embodiment, the BS according to claim 1, wherein the time domain and frequency domain resource sets are determined starting from a previously sent downlink transmission burst until the end of the first K>=1 mini-time slots or partial time slots of the downlink transmission burst including unicast PDSCH transmission.

[0503] In one embodiment, each ACK / NACK feedback bit in a HARQ-ACK / NACK set is provided to adjust the CWS at most once.

[0504] Next, at step 2604, the BS determines a set of time-domain and frequency-domain resources that contains a unicast physical downlink shared channel (PDSCH) transmission in a downlink transmission burst previously sent to at least one UE.

[0505] In one embodiment, when the BS performs a CWS adjustment decision, the previously transmitted downlink transmission burst is the most recent transmission burst, and wherein a set of HARQ-ACK / NACK feedback resources corresponding to the determined time and frequency domain resources is expected to be available or received.

[0506] Then, at step 2606, the BS adjusts a contention window size (CWS) based on a subset of the HARQ-ACK / NACK response set corresponding to unicast PDSCH transmission on the determined set of time and frequency domain resources.

[0507] In one embodiment, the BS is further configured to adjust the CWS based on the following: the proportion of NACKed transport blocks (TBs), that is, when the proportion of NACKed code block groups (CBGs) exceeds a predetermined threshold, the HARQ-ACK based on the CBG is the TB that is NACKed; or the weighted average proportion of NACK bits. In this embodiment, when the CBG that is NACKed exceeds the predetermined threshold, the CWS increases to the next available value; when the proportion of the CBG that is NACKed is less than or equal to the predetermined threshold, the CW is reset to the minimum value.

[0508] In one embodiment, the predetermined threshold is a non-decreasing threshold that adjusts the CWS according to the ratio between the number of HARQ-ACK values ​​expected to be received at the timing when the BS performs the CWS adjustment operation and the number of HARQ-ACK values ​​corresponding to the HARQ-ACK / NACK feedback resource set.

[0509] Then, in step 2608, the BS performs a listen-before-talk (LBT) operation with a configurable sensing duration based on the adjusted CWS.

[0510] Finally, in step 2610, the BS sends a downlink transmission via a downlink channel based on the LBT operation.

[0511] In one embodiment, the BS is configured to maintain the CWS without adjustment based on a predetermined maximum channel occupancy time (COT) when a HARQ-ACK / NACK feedback resource set is not available; and wherein the HARQ-ACK / NACK feedback resource set corresponds to a time domain and frequency domain resource set of a previously sent downlink transmission burst.

[0512] In one embodiment, the BS is configured to receive a radio resource measurement (RRM) report from at least one UE, the RRM report comprising at least one of a signal strength indicator, a channel occupancy report, or a measurement report associated with an unlicensed new radio (NR-U) wake-up signal.

[0513] In one embodiment, the BS is configured to adjust the CWS based on the RRM report and a threshold associated with the measurement quality.

[0514] Fig. 27 is a block diagram showing the structure of a gNB according to an embodiment of the present disclosure.

[0515] The above-mentioned gNB, eNB or BS may correspond to the gNB 2700. For example, Figure 2 The gNB 102 shown may correspond to gNB2700.

[0516] refer to Fig. 27, gNB 2700 may include a processor 2710, a transceiver 2720, and a memory 2730. However, not all components shown are required. gNB 2700 may include a processor 2710, a transceiver 2720, and a memory 2730. Fig. 27 The components shown in the figure may be implemented with more or fewer components. In addition, according to another embodiment, the processor 2710, the transceiver 2720, and the memory 2730 may be implemented as a single chip.

[0517] The aforementioned components will now be described in detail.

[0518] Processor 2710 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of gNB 2700 may be implemented by processor 2710.

[0519] Processor 2710 may determine a time domain and frequency domain resource set that includes a unicast physical downlink shared channel (PDSCH) transmission in a downlink transmission burst previously sent to at least one UE, adjust a contention window size (CWS) based on a subset of a HARQ-ACK / NACK response set that corresponds to the unicast PDSCH transmission on the determined time domain and frequency domain resource set, and perform a listen-before-talk (LBT) operation with a configurable sensing duration based on the adjusted CWS.

[0520] In one embodiment, when HARQ-ACK / NACK feedback resources are not available, processor 2710 may maintain the CWS without adjustment based on a predetermined maximum channel occupancy time (COT), and wherein the HARQ-ACK / NACK feedback resource set corresponds to a time domain and frequency domain resource set of a previously sent downlink transmission burst.

[0521] The transceiver 2720 may include an RF transmitter that up-converts and amplifies a transmitted signal and an RF receiver that down-converts the frequency of a received signal. However, according to another embodiment, the transceiver 2720 may be implemented by more or less components than those shown in the components.

[0522] The transceiver 2720 may be connected to the processor 2710 to send and / or receive signals. The signals may include control information and data. In addition, the transceiver 2720 may receive signals through a wireless channel and output the signals to the processor 2710. The transceiver 2720 may send signals output from the processor 2710 through a wireless channel.

[0523] In one embodiment, the transceiver 2720 may receive a radio resource measurement (RRM) report from at least one UE, the RRM report including at least one of a signal strength indicator, a channel occupancy report, or a measurement report associated with a new unlicensed radio (NR-U) wake-up signal.

[0524] In one embodiment, the transceiver 2720 may receive a hybrid automatic repeat request-acknowledgement / negative acknowledgement (HARQ-ACK / NACK) response set corresponding to a downlink transmission sent to the at least one UE via an uplink channel from at least one user equipment (UE). The transceiver 2720 may send a downlink transmission via a downlink channel based on the LBT operation.

[0525] The memory 2730 may store control information or data contained in a signal obtained by the gNB 2700. The memory 2730 may be connected to the processor 2710 and store at least one instruction or protocol or parameter of the proposed function, process and / or method. The memory 2730 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk drive and / or a CD-ROM and / or a DVD and / or other storage devices.

[0526] Fig.28 is a block diagram showing a structure of a user equipment (UE) according to an embodiment of the present disclosure.

[0527] refer to Fig.28 UE 2800 may include a processor 2810, a transceiver 2820, and a memory 2830. However, not all of the components shown are necessary. UE 2800 may include a processor 2810, a transceiver 2820, and a memory 2830. Fig.28 The components shown in the figure may be implemented with more or fewer components. In addition, according to another embodiment, the processor 2810, the transceiver 2820, and the memory 2830 may be implemented as a single chip.

[0528] The aforementioned components will now be described in detail.

[0529] The processor 2810 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operation of the UE 2800 may be implemented by the processor 2810.

[0530] In one embodiment, the processor 2810 may send a hybrid automatic repeat request-acknowledgement / negative (HARQ-ACK / NACK) response set corresponding to a downlink transmission received from the BS to a base station (BS) via an uplink channel, wherein the HARQ-ACK / NACK feedback resource set corresponds to a downlink transmission on a time domain and frequency domain resource set based on a downlink transmission burst previously received from the BS. The processor 2810 may receive a downlink transmission from the BS via a downlink channel based on a listen-before-talk (LBT) operation at the BS, wherein the LBT operation with a configurable sensing duration is determined based on a contention window (CWS) size, and the CWS is adjusted based on the HARQ-ACK / NACK feedback resource set.

[0531] The processor 2810 may detect the PDCCH on the configured control resource set. The processor 2810 may determine the method for dividing the CB and the method for performing PDSCH rate matching according to the PDCCH. The processor 2810 may control the transceiver 2820 to receive the PDSCH according to the PDCCH. The processor 2810 may generate HARQ-ACK information according to the PDSCH. The processor 3310 may control the transceiver 2820 to send the HARQ-ACK information.

[0532] The transceiver 2820 may include an RF transmitter that up-converts and amplifies a transmitted signal and an RF receiver that down-converts the frequency of a received signal. However, according to another embodiment, the transceiver 2820 may be implemented by more or less components than those shown in the components.

[0533] The transceiver 2820 may be connected to the processor 2810 to send and / or receive signals. The signals may include control information and data. In addition, the transceiver 2820 may receive signals through a wireless channel and output the signals to the processor 2810. The transceiver 2820 may send signals output from the processor 2810 through a wireless channel.

[0534] The memory 2830 may store control information or data contained in a signal obtained by the UE 2800. The memory 2830 may be connected to the processor 2810 and store at least one instruction or protocol or parameter of the proposed function, process or method. The memory 2830 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk drive and / or a CD-ROM and / or a DVD and / or other storage devices.

[0535] Nothing in this application should be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the subject matter of the patent is limited only by the claims. In addition, none of the claims is intended to refer to means or steps and functions (e.g., 35 U.S.C. §112(f)) unless the exact words "means for..." are followed by a participle.

Claims

1. A method for a base station in a wireless communication system, the method comprising: Determining reference time domain resources, the reference time domain resources comprising at least one unicast physical downlink shared channel (PDSCH) transmission sent to a user equipment (UE); Identifying a hybrid automatic repeat request HARQ acknowledgment feedback set received from the UE, wherein the HARQ acknowledgment feedback set includes confirmation feedback and / or negative confirmation feedback corresponding to the at least one unicast PDSCH transmission in the reference time domain resource; Adjusting the contention window size CWS based on the identified HARQ response feedback set; performing a channel access operation based on the adjusted CWS; and sending a downlink transmission via a downlink channel based on the channel access operation, The reference time domain resources are determined as from the beginning of a previous downlink transmission burst to the end of the first K time slot sets or mini-time slot sets in the previous downlink transmission burst including the at least one unicast PDSCH transmission.

2. The method according to claim 1, wherein: The previous downlink transmission burst is a most recent transmission burst for which the base station performs CWS adjustment, and Wherein, when the base station performs the CWS adjustment, at least some HARQ confirmation feedback corresponding to the at least one unicast PDSCH transmission in the reference time domain resource of the previous downlink transmission burst is available.

3. The method according to claim 1, wherein: Adjusting the CWS includes: The CWS is adjusted based on the identified proportion of NACKed transport blocks TB in the HARQ response feedback set.

4. The method according to claim 3, wherein: Adjusting the CWS includes: Increasing the CWS to a next available value based on the identified proportion of NACKed TBs in the HARQ response feedback set exceeding a predetermined threshold; and Based on the fact that the proportion of NACKed TBs in the identified HARQ response feedback set does not exceed the predetermined threshold, the CWS is reset to a minimum value.

5. The method according to claim 1, wherein: Adjusting the CWS includes: Based on the unavailability of the HARQ response feedback set, the CWS is maintained at a current value.

6. A base station in a wireless communication system, the base station comprising: Transceiver; and At least one processor operably connected to the transceiver, the at least one processor configured to: determining reference time domain resources, the reference time domain resources comprising at least one unicast physical downlink shared channel (PDSCH) transmission sent to a device UE; Identifying a hybrid automatic repeat request HARQ acknowledgment feedback set received from the UE, wherein the HARQ acknowledgment feedback set includes confirmation feedback and / or negative confirmation feedback corresponding to the at least one unicast PDSCH transmission in the reference time domain resource; Adjusting the contention window size CWS based on the identified HARQ response feedback set; performing a channel access operation based on the adjusted CWS; and sending a downlink transmission via a downlink channel based on the channel access operation, The reference time domain resources are determined as from the beginning of a previous downlink transmission burst to the end of the first K time slot sets or mini-time slot sets in the previous downlink transmission burst including the at least one unicast PDSCH transmission.

7. The base station according to claim 6, wherein: The previous downlink transmission burst is a most recent transmission burst for which the base station performs CWS adjustment, and Wherein, when the base station performs the CWS adjustment, at least some HARQ confirmation feedback corresponding to the at least one unicast PDSCH transmission in the reference time domain resource of the previous downlink transmission burst is available.

8. The base station according to claim 6, wherein: The at least one processor is configured to: The CWS is adjusted based on the identified proportion of NACKed transport blocks TB in the HARQ response feedback set.

9. The base station according to claim 8, wherein: The at least one processor is configured to: Increasing the CWS to a next available value based on the identified proportion of NACKed TBs in the HARQ response feedback set exceeding a predetermined threshold; as well as Based on the fact that the proportion of NACKed TBs in the identified HARQ response feedback set does not exceed the predetermined threshold, the CWS is reset to a minimum value.

10. The base station according to claim 6, wherein: The at least one processor is configured to: Based on the unavailability of the HARQ response feedback set, the CWS is maintained at a current value.

Images