Channel access mechanism in millimeter wave unlicensed band

Abstract

Some embodiments of the present disclosure provide a channel access mechanism configured in a millimeter wave shared spectrum mobile communication network. The channel access mechanism is to be used by a user equipment (UE) and a serving node in a serving cell of the UE. The configuration can use a single cell-specific higher layer parameter or a combination of two cell-specific higher layer parameters. The parameters can configure the UE and the node to perform channel sensing before transmitting to initiate channel occupancy. Alternatively, the UE and the node can be configured to transmit directly without channel sensing. The parameters can configure a receiver (UE or node) to perform channel sensing before transmitting a channel clear indication to a transmitter as part of a channel access procedure to initiate channel occupancy. Alternatively, the parameters can configure the UE and the node to receive without channel sensing.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 094,136, filed October 20, 2020, entitled “Channel Access Mechanisms in millimeter Wave Unlicensed Bands,” U.S. Provisional Patent Application No. 63 / 250,686, filed September 30, 2021, entitled “Channel Access Mechanisms in millimeter Wave Unlicensed Bands,” and U.S. Patent Application No. 17 / 504,200, filed October 18, 2021, entitled “Channel Access Mechanisms in millimeter Wave Unlicensed Bands,” all of which are incorporated by reference in the present application. TECHNICAL FIELD

[0003] The present disclosure relates generally to channel access mechanisms, and in particular embodiments, to channel access mechanisms in millimeter wave unlicensed bands. BACKGROUND

[0004] The 3rd Generation Partnership Project (3GPP) has extensively studied the operation of fifth generation (5G) mobile networks. 5G New Radio (NR) is the radio access technology (RAT) developed by 3GPP for 5G mobile networks. Notably, the frequency bands of 5G NR are considered to be divided into two different frequency ranges. The first frequency range is referred to as frequency range 1 (FR1). FR1 is defined to include frequency bands below 6 GHz. FR1 covers some of the frequency bands traditionally used by previous standards. FR1 also covers potential new spectrum opportunities from 410 MHz to 7125 MHz. The second frequency range is referred to as frequency range 2 (FR2). FR2 is defined to include frequency bands from 24.25 GHz to 52.6 GHz, referred to as “millimeter wave” or “mmWave” frequency range.

[0005] Recently, in a technical report (TR) studying NR operation above 52.6 GHz, it was decided to extend FR2 operation to 71 GHz (see 3GPP TR 38.807, “Study on requirements for NR beyond 52.6 GHz”). The extended frequency range for FR2, i.e., from 52.6 GHz to 71 GHz, is referred to as FR2-2, while the original frequency range for FR2 is referred to as FR2-1.

[0006] It is known that millimeter wave operation results in increased path loss relative to lower frequencies. However, it is also known that wireless nodes can be equipped with a large number of antenna elements. Therefore, it is expected that these wireless nodes can engage in beamforming and highly directional transmissions to combat the path loss.

[0007] 3GPP has published a study item description (SID) with a focus on supporting extension of NR operation to frequencies between 52.6 GHz and 71 GHz (see RP-200901 revision of SID: “Study on supporting NR from 52.6 GHz to 71 GHz”, RAN #88e). The cited SID addresses channel access mechanisms by considering three factors. The first factor is potential interference to / from other nodes assuming beam-based operation. The second factor is compliance with regulatory requirements applicable to unlicensed spectrum, i.e., 60 GHz shared spectrum. The third factor is coexistence with other existing radio access technologies (RATs) such as 802.11ad Directional Multi-Gigabit (DMG) or WiGig and / or 802.11ay Enhanced DMG (EDMG).

[0008] Furthermore, 3GPP has also published a work item description (WID) with the focus on supporting the extension of NR operation up to 71 GHz (see RP-193229 "New WID on Extending current NR operation to 71 GHz", RAN#86). The WID considers both licensed and unlicensed operation. It is known that New Radio-based access to Unlicensed (NR-U) is a RAT designed to operate in the 5 GHz and 6 GHz bands together with Wi-Fi. The WID proposes procedures to operate in the unlicensed 60 GHz band that are similar to the ones adopted by NR-U. The WID targets some physical layer aspects and procedures. In particular, for the newly introduced numerology, time axis related aspects are considered. The WID considers support for up to 64 Synchronization Block, SSB, beams for both licensed and unlicensed operation. Assuming that beam-based operation complies with regulatory requirements applicable to the 60 GHz unlicensed spectrum, the WID also considers channel access mechanisms. The WID also notes that for the proposed operation in the extended bands, NR / NR-U operation can be standalone or aggregated operation through carrier aggregation (CA) or dual connectivity (DC) with an anchor carrier. SUMMARY

[0009] Various aspects of the present application enable configuring and switching between different variants of LBT and non-LBT channel access mechanisms according to region-specific requirements and expectations for improved performance. The variants of channel access mechanisms include receiver-only LBT (receiver-only channel sensing), which can be seen to reduce the LBT overhead with respect to some known receiver-assisted LBT mechanisms.

[0010] It can be seen that operation using the receiver-only LBT channel access mechanism increases spatial reuse in a manner similar to operation without LBT, while mitigating the known problem of so-called "hidden node" issues sometimes found in channel access mechanisms relying on transmitter-only LBT or avoiding the use of LBT. In those instances where the intended receiver is configured to initiate channel occupancy, it can be seen that the proposed receiver-only LBT channel access mechanism relaxes the switching time between reception of the idle indication from the intended receiver and the transmission time. It can also be seen that the proposed receiver-only LBT channel access mechanism allows for configuration of a performance-centric energy detection threshold for receiver channel sensing when the intended receiver does not initiate channel occupancy.

[0011] According to an aspect of the present application, a method of operating a user equipment (UE) in a millimeter wave shared spectrum is provided. The method includes receiving, by the UE, at least one higher layer parameter that provides the UE with a semi-static configuration to operate with shared spectrum access in a serving cell within the millimeter wave shared spectrum according to one of a listen before talk (LBT) channel access mode and a without LBT (No-LBT) channel access mode; and transmitting, by the UE, an uplink (UL) transmission burst on a channel in the serving cell to initiate a channel occupancy on the channel. In the LBT channel access mode, the transmitting is performed after determining that the channel is idle using channel sensing according to the semi-static configuration of the LBT channel access mode provided by the at least one higher layer parameter. In the No-LBT channel access mode, the transmitting is performed directly according to the semi-static configuration of the No-LBT channel access mode provided by the at least one higher layer parameter.

[0012] According to an aspect of the present application, an apparatus for operating in a millimeter wave shared spectrum is provided. The apparatus includes a memory that stores instructions and a processor. Execution of the instructions by the processor causes the processor to receive at least one higher layer parameter that provides the apparatus with a semi-static configuration to operate with shared spectrum access in a serving cell within the millimeter wave shared spectrum according to one of a listen before talk (LBT) channel access mode and a without LBT (No-LBT) channel access mode; and transmit an uplink (UL) transmission burst on a channel in the serving cell to initiate a channel occupancy on the channel. In the LBT channel access mode, the processor is caused to transmit after determining that the channel is idle using channel sensing according to the semi-static configuration of the LBT channel access mode provided by the at least one higher layer parameter on the channel. In the No-LBT channel access mode, the processor is caused to transmit directly according to the semi-static configuration of the No-LBT channel access mode provided by the at least one higher layer parameter. BRIEF DESCRIPTION OF DRAWINGS

[0013] For a more complete understanding of the present embodiments and their advantages, reference is now made to the following examples by way of example, as illustrated in the following description, taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1 is a schematic diagram of a communication system in which embodiments of the disclosure can be applied, the communication system including an example user equipment and an example base station;

[0015] Figure 2 illustrated in block diagram form, of a communication system in accordance with various aspects of the present application Figure 1 an example user equipment of the communication system of

[0016] Figure 3 A block diagram illustrates various aspects according to this application. Figure 1 Example base station of a communication system;

[0017] Figure 4 The signal flow diagram of a downlink scenario in which the transmitter performs channel sensing is illustrated according to various aspects of this application. Figure 2 User equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the transmitter;

[0018] Figure 5 The signal flow diagram of the first uplink scenario in which the transmitter performs channel sensing is illustrated according to various aspects of this application. Figure 2 User equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the transmitter;

[0019] Figure 6 The signal flow diagram of the downlink scenario in which the receiver performs channel sensing is illustrated according to various aspects of this application. Figure 2 User equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the receiver;

[0020] Figure 7 The signal flow diagram of the uplink scenario in which the receiver performs channel sensing is illustrated according to various aspects of this application. Figure 2 User equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the receiver;

[0021] Figure 8 The signal flow diagram for a downlink scenario where both the transmitter and receiver perform channel sensing is illustrated according to various aspects of this application. Figure 2 For user equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the transmitter and receiver; and

[0022] Figure 9 The signal flow diagram for an uplink scenario where both the transmitter and receiver perform channel sensing is illustrated according to various aspects of this application. Figure 2 User equipment and Figure 3 Signaling exchange between base stations to notify user equipment that channel sensing will be performed at the transmitter and receiver. Detailed Implementation

[0023] For illustrative purposes, specific exemplary embodiments will now be explained in more detail with reference to the accompanying drawings.

[0024] The embodiments described herein represent information sufficient to practice the claimed subject matter and illustrate methods for practicing such subject matter. Upon reading the following description in conjunction with the accompanying drawings, those skilled in the art will understand the concepts of the claimed subject matter and recognize that the application of these concepts is not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0025] Furthermore, it should be understood that any module, component, or device with executable instructions disclosed herein may include or otherwise access a non-transitory computer / one or more processor-readable storage medium for storing information, such as computer / processor-readable instructions, data structures, program modules, and / or other data. A non-exhaustive list of examples of non-transitory computer / processor-readable storage media includes magnetic tape cassettes; magnetic tape; disk storage or other magnetic storage devices; compact disc read-only memory (CD-ROM); digital video discs or digital versatile discs (DVDs); and Blu-ray discs. TM Optical discs; or other optical storage devices; volatile and non-volatile, removable and non-removable media implemented in any method or technology; random-access memory (RAM); read-only memory (ROM); electrically erasable programmable read-only memory (EEPROM); flash memory or other storage technologies. Any of these non-transitory computer / processor storage media may be part of a device or may be accessed or connected to a device. Computer / processor-readable / executable instructions used to implement the applications or modules described herein may be stored or otherwise preserved by such non-transitory computer / processor-readable storage media.

[0026] Figure 1 An example communication system 100 is illustrated schematically. Typically, communication system 100 enables multiple wireless or wired components to transmit data and other content. The purpose of communication system 100 may be to provide content (voice, data, video, text) via broadcast, narrowcast, user equipment to user equipment, etc. Communication system 100 can operate by sharing resources such as bandwidth.

[0027] In this example, the communication system 100 includes a first user equipment (UE) 110A, a second UE 110B and a third UE 110C (individual or unified 110), a terrestrial radio access network (RAN) 120A and a non-terrestrial RAN 120B (individual or unified 120), a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. Although Figure 1 A certain number of these components or elements are shown, but the communication system 100 may include any number of these components or elements.

[0028] UE 110 is configured to operate and / or communicate in communication system 100. For example, UE 110 is configured to transmit and / or receive via a wireless communication channel. Each UE 110 represents any suitable end-user equipment that performs wireless operation and may include (or be referred to as) devices such as: wireless transmit / receive unit (WTRU), mobile station, mobile user unit, cellular phone, station (STA), machine-type communication (MTC) device, Internet of Things (IoT) device, personal digital assistant (PDA), smartphone, laptop, computer, touchpad, wireless sensor, or consumer electronic device.

[0029] exist Figure 1In this context, the terrestrial RAN 120A includes terrestrial base stations (BS) 170A, and the non-terrestrial RAN includes non-terrestrial base stations 170B (individual or unified 170). Base stations 170 may also be referred to as anchor points or transmit points (TPs). Each base station 170 is configured to radioly interface with one or more UEs 110 to enable access to any other base station 170, core network 130, PSTN 140, Internet 150, and / or other networks 160. For example, base station 170 may include (or may be) one or more of several well-known devices, such as a base transceiver station (BTS), Node B, evolved Node B (eNodeB), Home eNodeB, gNodeB (“gNB”), transmission and receive point (TRP), site controller, access point (AP), or wireless router. Any UE 110 can optionally or additionally be configured to interface, access, or communicate with any other base station 170, Internet 150, core network 130, PSTN 140, other network 160, or any combination thereof. The communication system 100 may include a RAN, such as RAN 120B, wherein the corresponding base station 170B accesses the core network 130 via Internet 150, as shown in the figure.

[0030] UE 110 and base station 170 are examples of communication devices that can be configured to implement some or all of the functions and / or implementations described herein. Figure 1In the illustrated embodiment, terrestrial base station 170A forms part of terrestrial RAN 120A, which may include other base stations (not shown), base station controllers (BSCs) (not shown), radio network controllers (RNCs) (not shown), relay nodes (not shown), components (not shown), and / or equipment (not shown). Any base station 170 may be a single or multiple components distributed within or otherwise distributed within a corresponding RAN 120. Furthermore, non-terrestrial base station 170B forms part of non-terrestrial RAN 120B, which may include other base stations, components, and / or equipment. Each base station 170 transmits and / or receives radio signals within a specific geographical area or region, sometimes referred to as a "cell" or "coverage area." A cell may be further divided into cell sectors; for example, base station 170 may employ multiple transceivers to provide services to multiple sectors. In some embodiments, established picocells or femtocells supported by radio access technologies may exist. In some implementations, multiple transceivers may be used for each cell using, for example, multiple-input multiple-output (MIMO) technology. The number of RANs 120 shown is merely exemplary. Any number of RANs can be envisioned when designing the communication system 100.

[0031] Base station 170 uses radio frequency (RF) wireless communication links, microwave wireless communication links, infrared (IR) wireless communication links, visible light (VL) communication links, etc., to communicate with one or more UEs 110 through one or more air interfaces 190. Air interface 190 can use any suitable wireless access technology. For example, communication system 100 can implement one or more orthogonal or non-orthogonal channel access methods in air interface 190, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), space division multiple access (SDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA).

[0032] Base station 170 can implement Universal Mobile Telecommunication System (UMTS) Universal Terrestrial Radio Access (UTRA) to establish air interface 190 using wideband CDMA (WCDMA). In this case, base station 170 can implement protocols such as high-speed packet access (HSPA), evolved HPSA (HSPA+), and optionally high-speed downlink packet access (HSDPA), high-speed packet uplink access (HSUPA), or both. Optionally, base station 170 can use LTE, LTE-A, LTE-B, and / or 5G New Radio (NR) to establish air interface 190 using evolved UTMS Terrestrial Radio Access (E-UTRA). It is envisioned that communication system 100 can use multi-channel access capabilities, including schemes as described above. Other wireless technologies used for implementing the air interface include IEEE 802.11, 802.15, 802.16, CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, IS-2000, IS-95, IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemes and wireless protocols can also be used.

[0033] RAN 120 communicates with core network 130 to provide various services to UE 110, such as voice communication services, data communication services, and other communication services. RAN 120 and / or core network 130 may communicate directly or indirectly with one or more other RANs (not shown), which may or may not be directly served by core network 130, and may or may not employ the same radio access technology as terrestrial RAN 120A, non-terrestrial RAN 120B, or both. Core network 130 may also serve as a gateway access between (i) RAN 120 or UE 110 or both and (ii) other networks (e.g., PSTN 140, Internet 150, and other networks 160).

[0034] UE 110 can communicate with each other through one or more sidelink (SL) air interfaces 180 using wireless communication links such as radio frequency (RF), microwave, infrared (IR), and visible light (VL) links. The SL air interface 180 can use any suitable radio access technology and can be substantially similar to, or substantially different from, the air interface 190 used by UE 110 to communicate with one or more base stations 170. For example, communication system 100 can implement one or more channel access methods, such as CDMA, TDMA, FDMA, SDMA, OFDMA, or SC-FDMA, in the SL air interface 180. In some implementations, the SL air interface 180 can be implemented at least partially on unlicensed spectrum.

[0035] Some or all of UE 110 may include the ability to communicate with different wireless networks via different wireless links using different wireless technologies and / or protocols. UE 110 may communicate with service providers or exchanges (not shown) and with the Internet 150 via wired communication channels, without wireless communication (or other than wireless communication). PSTN 140 may include a circuit-switched telephone network for providing plain old telephone service (POTS). The Internet 150 may include computer networks and subnets (internal networks) or both, and includes protocols such as Internet Protocol (IP), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP). UE 110 may be a multimode device capable of operating according to multiple wireless access technologies and includes multiple transceivers required to support multiple wireless access technologies.

[0036] Figure 2 and Figure 3 An example device is shown that can implement the methods and teachings according to this disclosure. In particular, Figure 2 Example UE 110 is shown, and Figure 3 Example base station 170 is shown. These components can be... Figure 1 Used in the communication system 100 or any other suitable system.

[0037] like Figure 2As shown, UE 110 includes at least one UE processing unit 200. The UE processing unit 200 implements various processing operations of UE 110. For example, the UE processing unit 200 may perform signal encoding, data processing, power control, input / output processing, or any other function that enables UE 110 to operate within the communication system 100. The UE processing unit 200 may also be configured to implement some or all of the functions and / or implementations described in detail above. Each UE processing unit 200 includes any suitable processing or computing device configured to perform one or more operations. For example, each UE processing unit 200 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0038] UE 110 also includes at least one transceiver 202. Transceiver 202 is configured to modulate data or other content for transmission by at least one antenna or network interface controller (NIC) 204. Transceiver 202 is also configured to demodulate data or other content received via at least one antenna 204. Each transceiver 202 includes any suitable structure for generating signals for wireless or wired transmission and / or for processing signals received wirelessly or wiredly. Each antenna 204 includes any suitable structure for transmitting and / or receiving wireless or wired signals. One or more transceivers 202 may be used in UE 110. One or more antennas 204 may be used in UE 110. Although transceiver 202 is shown as a single functional unit, it may also be implemented using at least one transmitter and at least one separate receiver.

[0039] UE 110 also includes one or more input / output devices 206 or interfaces (e.g., wired interfaces connected to the Internet 150). Input / output devices 206 support interaction with users or other devices on the network. Each input / output device 206 includes any suitable structure for providing or receiving information from the user, such as a speaker, microphone, keypad, keyboard, display, or touchscreen, including network interface communication.

[0040] Additionally, UE 110 includes at least one UE memory 208. UE memory 208 stores instructions and data used, generated, or collected by ED 110. For example, UE memory 208 may store software instructions or modules configured to implement some or all of the functions and / or implementations described above and executed by UE processing unit 200. Each UE memory 208 includes any suitable volatile and / or non-volatile storage and retrieval device. Any suitable type of memory can be used, such as random access memory (RAM), read-only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital card (SD card), etc.

[0041] like Figure 3 As shown, base station 170 includes at least one BS processing unit 350, at least one transmitter 352, at least one receiver 354, one or more antennas 356, at least one memory 358, and one or more input / output devices or interfaces 366. Transceivers (not shown) may be used instead of transmitters 352 and receivers 354. Scheduler 353 may be coupled to BS processing unit 350. Scheduler 353 may be included within base station 170 or operate separately from base station 170. BS processing unit 350 implements various processing operations of base station 170, such as signal encoding, data processing, power control, input / output processing, or any other function. BS processing unit 350 may also be configured to implement some or all of the functions and / or implementations detailed above. Each BS processing unit 350 includes any suitable processing or computing device configured to perform one or more operations. For example, each BS processing unit 350 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0042] Each transmitter 352 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each receiver 354 includes any suitable structure for processing signals wirelessly or wiredly received from one or more UEs or other devices. Although shown as separate components, at least one transmitter 352 and at least one receiver 354 may be combined as a transceiver. Each antenna 356 includes any suitable structure for transmitting and / or receiving wireless or wired signals. Although a common antenna 356 is shown herein coupled to both transmitter 352 and receiver 354, one or more antennas 356 may be coupled to transmitter(s)352, and one or more individual antennas 356 may be coupled to receiver(s)354. Each memory 358 includes any suitable volatile and / or non-volatile storage and retrieval devices, such as those described above in conjunction with UE 110. Memory 358 stores instructions and data used, generated, or collected by base station 170. For example, memory 358 may store software instructions or modules configured to implement some or all of the functions and / or implementations described above and executed by BS processing unit 350.

[0043] Each input / output device 366 can interact with users or other devices in the network. Each input / output device 366 includes any suitable structure for providing information to or receiving / providing information from users, including network interface communication.

[0044] The frequency band extending from 57 GHz to 66 GHz is known to be largely available in the United States, Canada, the European Union (EU), and Japan. The same band is also known to be partially available in other regions such as China, South Korea, and Australia. The frequency band extending from 57 GHz to 71 GHz is available in the United States and Canada. According to a recent decision by the European Conference of Postal and Telecommunications Administrations, Electronic Communications Committee (CEPT ECC), the frequency band extending from 57 GHz to 71 GHz will also be available in the European Union.

[0045] The International Telecommunication Union (ITU-R) requirements for multiple gigabit wireless systems (MGWS) operating in the 60 GHz band take into account a maximum channel bandwidth of 2.16 GHz and allow channel bonding. The European Telecommunications Standards Institute (ETSI) has specified regulatory requirements for MGWS operating in the 60 GHz band (excluding fixed outdoor installations) (see ETSI EN 302 567, “Multiple-Gigabit / s radioequipment operating in the 60 GHz band; Harmonised Standard covering the essential requirements of article 3.2 of Directive 2014 / 53 / EU”, V2.1.1, 2017-07).

[0046] Therefore, 802.11ad directional multi-gigabit (DMG) and 802.11ay enhanced DMG (EDMG) support channel bonding of contiguous channels and / or aggregation of discontinuous channels, thereby enabling the following possible transmission bandwidths for physical protocol data uUnits (PPDUs): 2.16 GHz; 4.32 GHz; 6.48 GHz; 8.64 GHz; 2.16+2.16 GHz and 4.32+4.32 GHz.

[0047] A review of current regulatory requirements in specific regions reveals that in the United States and China, a minimum occupied channel bandwidth (OCB) of 99% signal power is not required. The same applies to Japan, South Korea, Australia, and Singapore. However, in the European Union, according to the harmonized standard (HS) for MGWS and wideband data transmission system fixed (WDTS-fixed, see ETSI EN303 722, V0.0.4, 2020-05-18), the OCB must be between 70% and 100% of the declared nominal channel bandwidth. It is noteworthy that for MGWS, there are no requirements for the nominal center frequency and nominal channel bandwidth. A given manufacturer can declare the nominal channel bandwidth when testing its product. However, 802.11 DMG / EDMG systems currently support multiples of the 2.16 GHz channel (i.e., 2.16 GHz, 4.32 GHz, 6.48 GHz, and 8.64 GHz).

[0048] For MGWS, according to the latest CEPT ECC decision, the maximum power spectral density (PSD) has been relaxed from 13 dBm / MHz to 23 dBm / MHz. Combined with the 40 dBm total radio frequency (RF) effective isotropic radiated power (EIRP) limit, the minimum transmission bandwidth (BW) using full power is determined to be 50 MHz. Therefore, transmitting equipment can increase the transmission BW at the cost of reducing the PSD to below the maximum PSD. It should also be noted that considering the use of high antenna gain (≥30 dBi) during transmission, a higher PSD limit is allowed for WDTS-fixed.

[0049] Contention-based protocols are communication protocols used to operate wireless communication devices, allowing multiple users to use the same wireless channel without prior coordination. The "listen before talk" (LBT) protocol is a contention-based protocol in which devices apply clear channel assessment (CCA) before using the channel. The carrier sense multiple access / collision avoidance (CSMA / CA) operation procedure known in IEEE 802.11 is the most well-known form of an LBT contention-based protocol.

[0050] LBT is a mandatory requirement for MGWS in the EU, falling under the "adaptive" category. As a Media Access Protocol (MAP), it promotes spectrum sharing through energy-sensing-based CCA. The EU has not yet authorized LBT for outdoor deployments in wideband data transmission systems (WDTS-fixed). Regions where LBT is not mandatory include the United States, China, Japan, South Korea, Australia, and Singapore. Currently, the ETSI Broadband Radio Access Network (BRAN) Technical Committee has two ongoing work items (WIs), one for specifying the adaptive channel access mechanism (CRM) for fixed network radio equipment and mobile network radio equipment operating in the 57 GHz to 71 GHz bands.

[0051] On the one hand, the energy detection threshold (EDT) used for CCA is not applicable to the United States, China, and regions where LBT is not mandatory. On the other hand, for the European Union, so far only MGWS's HS has adjusted the EDT to [specific value]. Where P out For RF output power (EIRP), P Max The maximum power level (EIRP) is set to 40 dBm.

[0052] When NR devices initiate channel occupancy (CO) in the 60 GHz band, they consider many channel access mechanisms. Traditionally, channel access mechanisms performed by the transmitter include: (quasi)-omnidirectional LBT; directional LBT; and non-LBT. Each of these mechanisms has its advantages and disadvantages.

[0053] Omnidirectional LBT channel access mechanisms are used in RATs operating in the low-frequency bands (5 GHz and 6 GHz), such as licensed-assisted access (LAA), NR-U, and IEEE 802.11ac / ax. When operating under omnidirectional LBT, the device senses energy in the channel from all directions without combining array gain. Quasi-omnidirectional LBT channel access mechanisms are known to be used in IEEE 802.11ad / ay, where the device senses the channel over a wide beam that includes all possible transmission directions. Based on the reuse of the known Rel-16 NR-U LBT channel access mechanism, omnidirectional LBT channel access mechanisms can be considered relatively easy to implement. However, it may be argued that (quasi)omnidirectional LBT channel access mechanisms lead to an "overprotection" problem, thereby reducing spatial reuse, as potential transmissions with tolerable / harmless interference to the reception of ongoing transmissions may be blocked. This is sometimes referred to as the "exposed node problem."

[0054] Directed LBT channel access mechanisms are known to have the potential to improve channel access probability and enhance spatial multiplexing. However, when a directed LBT channel access mechanism is implemented at the transmitter side, the known "hidden node problem" may become more severe. That is, at the receiver, there may be interference from other nodes that are not detected by the LBT performed at the transmitter. The transmitter's failure to detect other nodes may be due to limited sensing directions. Other disadvantages include increased complexity and LBT overhead when the BS 170 uses, for example, beam scanning to serve multiple UEs 110 in different directions.

[0055] Channel access mechanisms that do not use LBT can be defined through direct transmission without requiring the transmitter to sense the channel. This direct transmission has been adopted in IEEE 802.11ad / ay in service life or time-division multiplexing modes. Non-LBT channel access mechanisms can be used for COs initiating high-directional transmissions, such as point-to-point links with beamforming gain > X dBi, or in areas where LBT is not legally mandated. Non-LBT channel access mechanisms offer advantages such as no overhead and direct reuse of NR operations in licensed bands. However, non-LBT channel access mechanisms can cause significant interference under high loads, especially for cell-edge UEs. Furthermore, it can be expected that the hidden node problem will be more severe for non-LBT channel access mechanisms than for directional LBT channel access mechanisms.

[0056] Another channel access mechanism to consider is based on a handshake mechanism between the transmitter and receiver before the transmitter occupies the channel. In other words, it is a receiver-assisted LBT channel access mechanism.

[0057] Receiver-assisted LBT channel access mechanisms may solve the known hidden node problem. The earliest version of this channel access mechanism is the IEEE 802.11 "Request to Send / Allow to Send" channel reservation mechanism, in which the source node uses an omnidirectional LBT to sense the channel and sends a request-to-send (RTS) frame indicating the duration for which the source node wants to occupy the channel.

[0058] Upon receiving an RTS frame, the destination node responds immediately after a short inter-frame spacing (SIFS) with a clear-to-send (CTS) frame. The CTS frame indicates the same end time as the CO indicated in the RTS frame. From the source node's perspective, some nodes are hidden nodes. These hidden nodes receive the CTS frame and responsively avoid accessing the channel by setting their network allocation vector (NAV) accordingly. The source node then continues transmission immediately after the SIFS following the end of the CTS frame, without requiring further channel sensing.

[0059] Especially in the 60 GHz unlicensed band, due to the large beamforming and path loss, it can be seen that the transmitter-side LBT is affected by both hidden and exposed node problems. Therefore, a receiver-assisted LBT is proposed as a channel access mechanism for the 60 GHz unlicensed band (see Appendix).

[0060] For downlink (DL) transmissions, UE 110 can receive the specifications of a spatial filter via the physical downlink control channel (PDCCH). UE 110 can perform directional channel sensing (LBT) using the specified spatial filter. UE 110 can also use the same spatial filter to receive DL transmissions on the physical downlink shared channel (PDSCH), thereby minimizing interference from other sources. At the transmitter end, BS 170 can perform omnidirectional channel sensing.

[0061] Similarly, for UL transmissions, BS 170 can schedule UL transmissions on the Physical Uplink Shared Channel (PUSCH) and can specify a spatial filter for PUSCH transmissions via UL scheduling grants transmitted on the PDCCH. BS 170 can perform directional channel sensing using a spatial receive filter associated with the specified spatial filter to access the channel and transmit the PDCCH. BS 170 can then use the same spatial receive filter to receive UL transmissions on the PUSCH, thereby minimizing interference from other sources. At the transmitter end, UE 110 can perform omnidirectional channel sensing.

[0062] Typically, system-level performance results show that the transmit-side LBT method reduces the capacity of highly directional transmissions under low to medium loads compared to the non-LBT method. This capacity reduction can be attributed to reduced spatial multiplexing and increased LBT overhead without significant gains from interference coordination. Conversely, under high traffic loads with fewer exposed nodes, performance gains from interference coordination can be demonstrated.

[0063] System-level performance results also demonstrate that receiver-assisted directional LBT is beneficial for cell-edge users who would otherwise experience high levels of interference at the receiver due to transmissions hidden to the serving BS 170 node. These benefits are shown to be even more pronounced under medium to high traffic loads.

[0064] Various aspects of this application can be configured with different variants of the LBT channel access mechanism and non-LBT channel access mechanism and switched between them according to region-specific requirements and expectations for improved performance.

[0065] Typically, a UE 110 operating in millimeter-wave shared spectrum can receive two cell-specific parameters related to the channel access mechanism.

[0066] In the first case, the first parameter configures UE 110 to perform channel sensing before transmitting a transmission used to initiate channel occupancy. In the second case, the first parameter configures UE 110 to transmit directly, i.e., without performing channel sensing.

[0067] In the first case, the second parameter configures UE 110 to perform channel sensing before sending a transmission to the transmitter, the transmission being used as part of the channel access procedure to indicate an empty channel to initiate channel occupancy. In the second case, the second parameter configures UE 110 to receive without performing channel sensing.

[0068] Various aspects of this application relate to a receive-only directional channel sensing mechanism, depending on whether LBT is mandatory or not.

[0069] Various aspects of this application relate to configurations including: transmitter-only channel sensing; receiver-only channel sensing; channel sensing performed by both the transmitter and receiver; and no channel sensing at all. It is worth noting that it is not necessarily expected that a combination of parameters corresponding to all these configurations will always be provided for a given UE 110. In fact, scenarios where at least one of these configurations is invalid will inevitably exist.

[0070] According to various aspects of this application, BS 170 can configure the UE serving cell for operation in millimeter-wave shared spectrum, such as 60 GHz unlicensed spectrum. The UE serving cell can also be referred to as a component carrier (CC). This configuration can be accomplished by sending an information element (IE) including one or more cell-specific parameters to UE 110.

[0071] In 5G NR, UE 110 can operate in one of three radio resource control (RRC) states: RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE. In other documents, these states may be referred to as "modes," such as "RRC_IDLE mode." When UE 110 is in the RRC_CONNECTED state, as a result of the connection establishment process, UE 110 is considered to be connected to BS 170. When UE 110 has transitioned to the RRC_IDLE state, that is, through a release procedure, UE 110 is not connected to BS 170, but BS 170 is aware that UE 110 exists in the network. By switching to the RRC_INACTIVE state, for example through a release and suspension procedure, UE 110 helps conserve network resources and UE power (thus extending, for example, perceived battery life). The RRC_INACTIVE state is known to be useful, for example, in cases where UE 110 is not communicating with BS 170. When UE 110 is in the RRC_INACTIVE state, both BS 170 and UE 110 store at least some configuration information, enabling UE 110 to reconnect to BS 170 via a recovery procedure, which is faster than if UE 110 could reconnect via a connection establishment procedure. In this case, UE 110 is in the RRC_IDLE state. Storing at least some configuration information while UE 110 is in the RRC_INACTIVE state is one aspect that distinguishes it from the RRC_IDLE state.

[0072] When UE 110 is in RRC_INACTIVE mode or RRC_IDLE mode, the way information can be sent to UE 110 via signals can include so-called "common signaling". When UE 110 is in RRC_CONNECTED mode, the way information can be sent to UE 110 via channels can include "UE-specific signaling" or "dedicated signaling".

[0073] Therefore, when UE 110 is in RRC_IDLE mode, BS 170 can use common signaling to send an IE containing parameters to UE 110. Example blocks of common signaling that can be used to send an IE include the known synchronization signal block (SSB), the known master information block (MIB), and the known system information block (SIB).

[0074] Furthermore, when UE 110 is in RRC_CONNECTED mode, BS 170 can use dedicated signaling to send an IE containing parameters to UE 110. This dedicated signaling can be related to configuring UE 110 using a secondary cell (SCell) or configuring UE 110 using a secondary cell group (SCG).

[0075] The commonality between public and private signaling is that they both communicate at a layer higher than the physical layer (i.e., Layer 1 in the known Open Systems Interconnection model). Since the IE is sent to the UE 110 via either public or private signaling, this parameter can be referred to as a higher-layer parameter. The term "higher layer" indicates that the parameter is sent to the UE 110 using communication at a layer higher than Layer 1. Of course, as is known, the signaling will still pass through the physical layer.

[0076] Since various aspects of this application involve shared spectrum channel access, it is beneficial to review the 3GPP technical specification, which is called TS 37.213, Group Radio Access Network; Physical layer procedures for shared spectrum channel access, V16.2.0, June 2020, which may be referred to as "Version 16" below.

[0077] In the first generalized aspect of this application, which relates to transmitter-only channel sensing, it should be clear that for DL ​​transmission, the transmitter is BS 170, and for UL transmission, the transmitter is UE 110. According to this first generalized aspect, BS 170 may send an IE to UE 110 including a first parameter indicating that channel sensing will be performed by the transmitter.

[0078] In the DL scenario, BS 170 will perform channel sensing on the channels within the serving cell bandwidth of UE 110. Figure 4The signal flow diagram for a DL scenario illustrates the signaling exchange between UE 110 and BS 170 to notify UE 110 that channel sensing will be performed by the transmitter. BS 170 can notify UE 110 that channel sensing will be performed by the transmitter by sending (step 402) an IE including one or more cell-specific parameters. UE 110 receives (step 404) the IE and determines that a first parameter indicates that channel sensing will be performed by the transmitter before transmission to initiate CO. It should be clear that this configuration is semi-static. That is, a transmission with an IE having the first parameter is not dynamically sent (step 402) before each DL transmission. BS 170 performs (step 416) channel sensing based on the first parameter. In response to sensing (step 416) that the channel is idle, BS 170 can send (step 418) a DL transmission burst to initiate CO. In version 16, a DL transmission burst is defined as a set of transmissions from the eNB / gNB without any gaps greater than 16 μs. For operation in millimeter-wave shared spectrum, a DL transmission burst can be defined as a set of transmissions from the BS 170 with no gaps or gaps no greater than X μs (X μs can be 3 μs or 8 μs). In the latter case, transmissions from the BS 170 separated by gaps greater than X μs are considered separate DL transmission bursts. The BS 170 can transmit transmissions after gaps within a DL transmission burst without sensing the availability of the corresponding channel.

[0079] In the UL scenario, UE 110 performs channel sensing on the channels within the bandwidth of its serving cell.

[0080] Figure 5The signal flow diagram for a UL scenario illustrates the signaling exchange between UE 110 and BS 170 to notify UE 110 that channel sensing will be performed by the transmitter. BS 170 can notify UE 110 that channel sensing will be performed by the transmitter by sending (step 502) an IE including one or more cell-specific parameters. UE 110 receives (step 504) the IE and determines a first parameter indicating that channel sensing will be performed by the transmitter. UE 110 performs (step 522) channel sensing based on the first parameter. In response to sensing (step 522) a channel idle, UE 110 can send (step 524) a UL transmission burst to initiate CO. In Release 16, a UL transmission burst is defined as a set of transmissions from UE 110 without any gaps greater than 16 μs. For operation in millimeter-wave shared spectrum, a UL transmission burst can be defined as a set of transmissions from UE without any gaps or with gaps no greater than X μs (X μs can be 3 μs or 8 μs). In the latter case, transmissions from UE 110 separated by gaps exceeding X μs are treated as separate UL transmission bursts. UE 110 can send transmissions after the gaps within the UL transmission bursts without sensing the availability of the corresponding channel.

[0081] In some aspects of this application, UE 110 can perform (step 522) directional channel sensing based on received parameters. Channel sensing is directional by selecting and using a spatial filter. In some aspects of this application, the spatial filter used for sensing is the same spatial filter that UE 110 later uses for UL transmission.

[0082] To assist in selecting a spatial filter, UE 110 can obtain spatial relationship information. It is known that UE 110 can obtain spatial relationship information using a reference signal.

[0083] On one hand, UE 110 can transmit multiple reference signals. At BS 170, multiple reference signals can be received and measured. After the measurement, BS 170 can send (step 516) a spatial filter instruction in the form of an indication of the specific reference signal received with the highest strength among the multiple reference signals to UE 110. Upon receiving (step 518) the instruction from BS 170, UE 110 can select a spatial filter corresponding to the specific reference signal. A known sounding reference signal (SRS) can be considered a good candidate reference signal.

[0084] On the other hand, UE 110 can receive multiple reference signals transmitted by BS 170. Upon receiving a reference signal, UE 110 can perform measurements and select the optimal DL RS resource based on the measurements, as well as a specific spatial filter corresponding to the configuration that generates a strong received reference signal. UE 110 sends a measurement report to BS 170, indicating the optimal DL RS resource that UE 110 has selected. When selecting a specific spatial filter, UE 110 can transmit to BS 170 using the specific spatial filter on multiple SRS resources. It is expected that the specific spatial filter will result in a UL signal received at BS 170 with greater strength than the UL signal that has undergone an alternative spatial filter. Known SSBs and known channel state information reference signals (CSI-RS) can be considered as good candidate DL reference signals. Then, BS 170 performs measurements on the SRS resources and selects a specific SRS resource.

[0085] For subsequent UL transmissions, such as PUCCH or SRS, BS 170 can, for example, send / provide (step 516) spatial relation information to UE 110 via RRC signaling, indicating the DL RS resource index or UL RS resource index associated with the UL transmission. In some aspects, BS 170 can send multiple IEs to UE 110, each of which includes spatial relation information. UE 110 can receive the IEs and store the spatial filter in UE memory 208. Subsequently, BS 170 can activate / deactivate a specific spatial information IE by sending a specified MAC control element (CE) to UE 110. Upon receiving spatial relation information for the UL transmission, UE 110 determines that channel sensing to be performed prior to the UL transmission is directional. In some aspects of this application, UE 110 can selectively use the same spatial filter used for directional sensing as the spatial filter used by UE 110 to receive the DL RS indicated in the spatial relation information. In other aspects of this application, UE110 may optionally use the same spatial filter as the spatial filter used for directional sensing and the spatial filter used by UE110 to transmit the UL RS indicated in the spatial relationship information.

[0086] It is known that UE 110 can perform UL transmissions with timing based on UL scheduling authorization selected from BS 170. The spatial filter indication can be explicitly or implicitly indicated in the parameters included in the UL scheduling authorization. For example, a transmit precoder mMatrix indicator (TPMI) for codebook PUSCH transmissions or an SRS resource indicator (SRI) for non-codebook PUSCH transmissions, respectively. It is known that the UL scheduling authorization can be provided to UE 110 dynamically (in the downlink control information (DCI) on the PDCCH); or semi-statically via higher-layer signaling such as RRC signaling or a combination of RRC signaling and activated DCI. UE 110 can select and use the same spatial filter for orientation sensing as the spatial filter indicated in the UL scheduling authorization for transmitting UL transmissions. In some aspects, if cell-specific parameters have been provided and the channel sensing to be performed by the transmitter is directional, the UL scheduling authorization includes additional parameters that explicitly or implicitly indicate the spatial sensing filter that the UE 110 will use before transmitting the authorized UL transmission.

[0087] Return to DL scene ( Figure 4 In some aspects of this application, BS 170 can perform (step 416) directional channel sensing based on received parameters. Channel sensing is directional by selecting and using a spatial filter. In some aspects of this application, BS 170 reuses the spatial filter used for sensing for DL ​​transmission. One example where such reuse may be appropriate is a special case where a quasi-co-location (QCL) relationship exists between a reference DL RS in a set of RSs (transmission configuration indication states) and the intended RS for DL ​​transmission that BS 170 will use. BS 170 can provide (… Figure 4Step 411) is given to UE 110. For example, this special case occurs when BS 170 performs DL transmission on the physical downlink control channel ("PDCCH") or on the physical downlink shared channel ("PDSCH"), both using the demodulation reference signal ("DMRS") port. BS 170 can indicate to UE 110 the TCI state it has used for DL ​​transmission in the scheduling of DL allocation, so BS 170 can reuse the spatial filter associated with the indicated TCI state to perform directional channel sensing before transmitting the DL transmission.

[0088] In some aspects of this application, the transmitter performs omnidirectional channel sensing. As described above, for DL ​​transmission, the transmitter is BS 170, while for UL transmission, the transmitter is UE 110. In the UL scenario, the parameters received by UE 110, in addition to instructing UE 110 to perform channel sensing, can also explicitly indicate the type of sensing to be performed. The parameters can indicate the type of omnidirectional channel sensing to be performed, or the parameters can indicate the type of directional channel sensing. Alternatively, UE 110 can be configured to interpret instructions in the parameters to perform channel sensing without further indication of a specific channel sensing type as an implicit instruction that UE 110 will perform the omnidirectional channel sensing type.

[0089] When preparing DL transmissions (i.e., channel occupancy) in various directions using the BS 170, the BS 170 can use spatial sensing filters for all different directions, such as wide-beam spatial sensing filters, to perform channel sensing on various channels corresponding to each direction. This approach can be considered as representing quasi-omnidirectional channel sensing. Instead of sensing the corresponding direction, the BS 170 can identify QCL relationships between various directions and a set of channels associated with, for example, PDSCH or PDCCH DMRS ports.

[0090] It is worth noting that there may be cases where the spatial relationship or QCL relationship is channel sensing-specific, that is, the relationship used to determine the spatial filter used for channel sensing is different from the relationship used to determine the spatial transmit filter or spatial receive filter.

[0091] UE 110 can measure multiple SSBs and select the optimal SSB. To initiate a channel access procedure, UE 110 uses system information to determine the Physical Random Access Channel (PRACH) resource associated with the optimal SSB. In some aspects, if UE 110 selects a spatial filter for transmitting PRACH (Msg1 for a Type 1 random access procedure) or a spatial filter for transmitting both PRACH and PUSCH (Msg A for a Type 2 random access procedure), then UE 110 can perform channel sensing using the same spatial filter before transmitting the UL transmissions associated with the random access procedure, i.e., Msg1 / Msg3 or Msg A. At BS 170, upon receiving PRACH, BS 170 determines the optimal SSB selected by UE 110 and performs channel sensing using the same spatial transmission filter used by BS 170 for transmitting the optimal SSB before transmitting the DL transmissions associated with the random access procedure, i.e., Msg2 / Msg4 or Msg B. In some other respects, the UE110 or BS170 determines the spatial sensing filter, just as cell-specific parameters indicate that the channel sensing type is directional; if the cell-specific parameters indicate otherwise, the UE110 or BS170 uses omnidirectional channel sensing before transmitting transmissions associated with the random access procedure.

[0092] In the second generalized aspect of this application, which pertains to receiver-only channel sensing, it should be clear that for DL ​​transmission, the receiver is UE 110, while for UL transmission, the receiver is BS 170. According to this second generalized aspect, BS 170 may send an IE to UE 110 including a second parameter indicating that channel sensing will be performed at the receiver.

[0093] Typically, DL transmissions to UE 110 are scheduled by BS 170. Prior to such a scheduled DL transmission, BS 170 may send a DL scheduling assignment to UE 110. Similarly, typically, UL transmissions to UE 110 are scheduled by BS 170. Prior to such a scheduled UL transmission, BS 170 may send a UL scheduling authorization to UE 110.

[0094] Since the second broad aspect of this application relates to channel sensing to be performed at the receiver, it is expected that the BS 170 will not perform channel sensing to access channels within the serving cell bandwidth for the UE 110 to transmit DL scheduling allocations or UL scheduling grants. It is known that there exist regions where LBTs are authorized to a certain extent by regulations, such as the 75 band in ITU-R Area 1. However, even in these regions, it is not expected that the BS 170 will perform channel sensing because if the DL scheduling allocation transmission and the UL scheduling grant transmission are transmitted independently of the CO initiated according to the channel sensing process, the DL scheduling allocation transmission and the UL scheduling grant transmission will be considered as “short control signaling” transmissions.

[0095] From the signal flow graph representing the DL scenario Figure 6 As can be seen, only the intended receiver of the DL transmission, namely UE 110, performs receiver channel sensing. According to various aspects of this application, the receiver channel sensing performed by UE 110 is directional.

[0096] UE 110 detects the reception (step 606) of DL scheduling allocation. It should be understood that prior to receiving (step 606) the DL scheduling allocation, UE 110 had already received (step 604) the IE that BS 170 had sent (step 602), and UE 110 had determined that the first parameter included in the IE indicated that channel sensing would be performed at the receiver.

[0097] UE 110 can use a spatial filter to perform (step 616) directional receiver channel sensing. In one instance, the spatial filter can be associated with the PDSCH reception from BS 170. In another instance, the spatial filter can be associated with the PDCCH reception from BS 170. In yet another instance, the spatial filter can be associated with the PDCCH reception already received from BS 170 (…). Figure 6 (Not shown) The direction of the strongest reference signal (CSI-RS / SSB) is associated. In another instance, the spatial filter is associated with the PDCCH DMRS port received from BS 170, which is determined by the QCL relationship indicated by the TCI state in the DCI assigned by the DL scheduler; each TCI state indicates that the PDCCH is associated with CSI-RS, TRS, or SSB (a QCL relationship exists). The association of the spatial filter with the reception on a particular channel may depend on the QCL relationship provided to UE 110 by BS 170 ( Figure 6(Not shown). BS 170 can also indicate to UE 110 the spatial filter in the DL scheduling allocation received in step 602. For example, BS 170 can indicate the spatial filter to UE 110 by referring to the value in the dedicated SRS resource indicator (SRI) field, and referencing the spatial filter that UE 110 has used to transmit the SRS indicated by the SRI field. In another example, the spatial sensing filter is the same spatial filter that UE 110 uses to transmit aperiodic SRS triggered by the SRS request field in the DL scheduling allocation.

[0098] In response to sensing (step 616) a channel that is idle during the sensing duration, UE 110 sends (step 617) a short UL signal to BS 170 to indicate "idle channel". Alternatively, UE 110 may use a known PHY channel (e.g., PUCCH) to send (step 617) the "idle channel" indication to BS 170. UE 110 may use aperiodic SRS to send (step 617) the short UL signal to BS 170. Alternatively, UE 110 may use PUCCH to send (step 617) the short UL signal to BS 170. In either case, the transmission of the short UL signal (step 617) may be scheduled by BS 170 in the DL scheduling allocation received in step 606. Alternatively, the transmission of the short UL signal may be configured to begin a predetermined number of N symbols before BS 170 initiates the transmission of the DL transmission burst (step 618) within the serving cell bandwidth for UE 110 to initiate CO. It is worth noting that the latter alternative is effective when the receiver initiates the CO task, but ineffective when the transmitter initiates the CO task. A possible use case for configuring a number of N symbols is when configuring DL transmissions in a semi-static manner, such as semi-persistent scheduling (SPS) for PDSCH.

[0099] In some respects, BS 170 can simultaneously schedule multiple DL transmission bursts to multiple UEs 110, where the UEs 110 are spatially separated. In this scenario, multiple idle channel indications may be required; that is, each scheduled UE 110 may need to send an idle indication to BS 170 after sensing that a channel is idle. BS 170 can trigger A-SRS individually from each scheduled UE 110, for example, using the SRS request field in the corresponding DL scheduling allocation, or using a group common DCI, such as DCI format 2_3 configured with the higher-layer parameter "srs-TPC-PDCCH-Group" set to "Type B" or "Type A" and sent previously, to trigger multiple A-SRS transmissions. UEs 110 scheduled in this spatial multiplexing mode may not expect to receive the group common trigger DCI a number of M processing delay symbols prior to the start of the triggered A-SRS. In some respects, as part of the process of triggering DCI by the decoding group, UE 110 that has been addressed by the DCI scrambling group public RNTI but has not yet been scheduled in this spatial multiplexing mode can ignore the SRS request.

[0100] In a UL scenario, only the intended receiver for UL transmission, namely BS 170, performs receiver channel sensing. According to various aspects of this application, the receiver channel sensing performed by BS 170 is directional. Figure 7 This represents the signal flow diagram for a UL scenario.

[0101] UE 110 detects that it has received (step 714) the UL scheduling grant that BS 170 has sent (step 712). It should be understood that long before receiving (step 714) the UL scheduling grant, UE 110 has already received (step 704) the IE that BS 170 has sent (step 702), and UE 110 has determined that the first parameter included in the IE indicates that channel sensing will be performed at the receiver.

[0102] BS 170 can use a spatial filter to perform (step 716) directional receiver channel sensing. In one instance, the spatial filter can be associated with PUSCH reception from UE 110; for example, BS 170 can use the same spatial filter as the CSI-RS or SSB that BS 170 uses to transmit the SRS resource index indicated by the SRI field in the UL scheduling authorization; or BS 170 can use the same spatial reception filter associated with the TPMI indicated in the UL scheduling authorization. In another instance, the spatial filter can be associated with PUCCH reception from UE 110. In yet another instance, the spatial filter can be associated with (…) received from UE 110. Figure 7(Not shown) The direction of the strongest reference signal (SRS) is associated. The association between the spatial filter and the reception of a specific UL channel can be based on the spatial relationship information provided to UE 110 by BS 170. The association between the spatial filter and the reception of a specific UL channel can also be based on the most recently specified MAC-CE sent to UE 100 by BS 170.

[0103] In response to sensing (step 716) a channel that is idle during the sensing duration, BS 170 sends (step 717) a short DL signal to UE 110 to indicate "idle channel". Alternatively, BS 170 may use a PHY channel (e.g., PDCCH) to indicate "idle channel" to UE 110. BS 170 may use non-zero power (NZP) CSI-RS resources to send (step 717) the short DL signal to UE 110. Alternatively, BS 170 may use a scheduled PDCCH to send (step 717) the short DL signal to UE 110. In any case, the transmission of the short DL signal (step 717) may be scheduled or triggered by BS 170 in UL scheduling authorization. In some respects, when UE 110 is configured with an aperiodic SRS associated with an aperiodic NZP CSI-RS resource, the presence of the associated CSI-RS is indicated by the SRS request field if the value of the SRS request field is not “00”; the CSI-RS will be located in the same time slot as the SRS request field. Alternatively, the transmission of short DL signals can be configured to begin a preset number of N symbols before UE 110 starts transmitting (step 718) a UL transmission burst (step 718) to initiate a CO within the serving cell bandwidth for UE 110. One possible use case for configuring N symbols is when the UL transmission is semi-statically configured, such as a PUSCH transmission with a configured grant (CG) or a periodic PUCCH transmission.

[0104] The second parameter included in the IE can also provide an indication that the receiver is authorized to initiate a CO. This configures a receiver-initiated CO, rather than a typical transmitter-initiated CO. When initiating a CO, the receiver can share the initiated channel occupancy with the transmitter. It can be found useful in situations where including an indication that the receiver is authorized to initiate a CO in the second parameter is helpful, such as configuring the serving cell in frequency bands within areas where LBT is defined by a certain level of regulation, for example, in band 75 in ITU-R Area 1.

[0105] When performing channel sensing, it can be considered that ( Figure 6 Step 616 in the middle Figure 7In step 716, the sensed entity (e.g., UE 110 or BS 170) senses a given channel over multiple time slots, hereinafter referred to as "sensing time slots". Therefore, the duration of sensing can be expressed as multiple time slots.

[0106] Various aspects of this application relate to sensing using random durations. Since the duration of a time slot is pre-configured, a random duration can be implemented as a random number of time slots.

[0107] In one example, channel sensing can be performed according to a so-called Type 1 UL / DL channel access procedure. Hereinafter, the value p represents a single channel access priority class (CAPC) value associated with a DL / UL transmission sharing a CO initiated by the receiver. d =T f +m p *T sl T f m represents a fixed duration p T represents the number of consecutive sensing time slots following a fixed duration. sl This represents the duration of a sensing time slot. It's worth noting that the integer number of consecutive sensing time slots m... p Associated with the CAPC value p, which is related to the DL / UL transmission. Channel sensing can be performed over N consecutive random time slots. The generation of the random number N may involve selecting from the interval [0, CW]. p Select a number from the list, where CW p This represents the size (in time slots) of the contention window associated with the CAPC value p. The contention window size value is CW. p It cannot be less than three time slots; otherwise, it can be the minimum CW value configured for the CAPC value p. min,p With the maximum value CW max,p Between. That is, max{3,CW min,p}≤CW p ≤CW max,p In one example, T f =3μs,T sl =5μs,m p ≥1.

[0108] The maximum EDT used by the receiver can be set to the maximum value of EDT calculated based on the "idle indication" transmission parameter associated with the receiver. Rx and the maximum value EDT calculated based on the transmission parameters associated with the transmitter. Tx The minimum value in the range. Transmission parameters associated with the transmitter may include output power P. outOne or more of the following: total transmitted power, transmitter antenna gain, beamforming gain, and potential transmission bandwidth for subsequent transmission.

[0109] When the receiver is UE 110, BS 170 can provide UE 110 with the transmission parameters or maximum value EDT associated with BS 170 via higher-layer signaling.

[0110] The transmission duration of the transmitter is expected to not exceed the maximum channel occupancy time (MCOT)T starting from the channel occupancy time (COT) initiated by the receiver. mcot,p .

[0111] In all aspects of this application, the duration of any transmission gap can be counted in the COT. Alternatively, the COT may only count the duration of transmission gaps less than or equal to a specific duration (e.g., 8 μs). If multiple CAPC values ​​are not defined, a common MCOT value, such as T, can be used. mcot,p =5 ms.

[0112] Without the receiver initiating CO, the sensing duration, i.e., the number of time slots used for sensing, can be deterministic or random. If a CAPC value p is defined, the contention window can be set to a known minimum (three sensing time slots), or it can be set to the minimum CW associated with the CAPC value p. min,p .

[0113] Even if the receiver does not initiate a CO, it is expected that the receiver (i.e., has already detected reception) will still receive the CO. Figure 6 Step 606) DL scheduling assigned UE 110 or has already sent ( Figure 7 Step 714) UL scheduling authorized BS 170) performs (steps 616, 716) directional receiver channel sensing before the transmitter accesses the channel within the serving cell bandwidth of UE 110 to send (steps 618, 718) burst to initiate CO.

[0114] When UE 110 is the intended receiver, UE 110 may use a spatial filter associated with PDSCH reception from BS 170. Alternatively, UE 110 may use a spatial filter associated with PDCCH reception. Further alternatively, UE 110 may use a spatial filter associated with the optimal CSI-RS / SSB reception direction from BS 170.

[0115] BS 170 can also indicate the spatial filter to UE 110 in DL scheduling allocation, for example, by means of the value in the dedicated SRI field.

[0116] When BS 170 is the intended receiver, BS 170 may use a spatial filter associated with PUSCH reception from UE 110. Alternatively, BS 170 may use a spatial filter associated with PUCCH reception. Further alternatively, BS 170 may use a spatial filter associated with the optimal SRS reception direction from UE 110.

[0117] Even if the decision about whether a channel is busy or idle is a binary decision, the detected conditions may not be binary; that is, receiver channel sensing can be defined as determining the interference level. Receiver channel sensing can be particularly important when the interference originates from a node hidden from the transmitter's perspective. The receiver can interpret a specific interference level, i.e., an interference level exceeding a threshold, as detrimental to the reception of future transmissions. When the receiver determines that the detected interference level exceeds the threshold, it can consider the channel busy. In fact, from the transmitter's channel sensing perspective, the receiver does not need to use the regulatory-set EDT formula, for example, a function of only the transmitter's output power, without considering the receiver's location within the coverage area and relative to the jammer.

[0118] To determine whether harmful interference is present, the receiver can measure the interference level and compare it with the receiver's maximum energy detection threshold (EDT). Rx The EDT can be determined using a different formula than the one used to determine the transmitter's maximum energy detection threshold. Rx .

[0119] When UE 110 is the receiver, EDT can be determined by adding a configurable offset in dB, such as a signal-to-interference-plus-noise ratio (SINR) offset, to the reference signal received power (RSRP) threshold. Rx The value of, that is,

[0120]

[0121] The significance of the RSRP threshold as a reference level is that it indicates the minimum level of received power that UE 110 will accept in relation to serving BS 170.

[0122] When BS 170 is the receiver, EDT RxThe value can be determined at least based on the target received power P0(j) for each resource block (RB). This value can be found in the open-loop UL power control (PC) parameters provided to the UE 110 by the BS 170. For P0(j), j corresponds to the value in the SRI field included in the UL scheduling grant, and for the configured grant PUSCH, j = 1.

[0123] The actual number of radio blocks allocated in the UL scheduling grant can be used to extend P0(j) by the bandwidth of a given subcarrier spacing (SCS) or by the maximum number of RBs that can be allocated within the active bandwidth part (BWP). In one example, the maximum number of radio blocks allocated in the UL scheduling grant is 275 radio blocks per component carrier.

[0124] It can be shown that the various aspects related to channel sensing to be performed at the receiver in this application reduce LBT overhead compared to some known receive-assisted LBT mechanisms. It can be shown that operation using the LBT channel access mechanism at the receiver increases space reuse in a manner similar to operation without LBT, while mitigating known problems sometimes found in channel access mechanisms that avoid LBT, namely the so-called "hidden node" problem. In those instances where the intended receiver is configured to initiate channel occupancy, it can be shown that the proposed LBT channel access mechanism performed at the receiver relaxes the handover time between the reception time and transmission time of the idle indication from the intended receiver. This is because current ETSI BRAN regulations (see EN 302 567 and EN 302 722) do not specify the maximum duration of the initiated DL-to-UL or UL-to-DL handover gap within the CO. It can also be shown that the proposed LBT channel access mechanism performed at the receiver allows for the configuration of a performance-centric energy detection threshold for receiver channel sensing when the intended receiver does not initiate channel occupancy.

[0125] A third generalized aspect of this application relates to channel sensing configured to occur at both the transmitter and receiver. According to this third generalized aspect, the BS 170 can send a first parameter in an IE indicating that transmitter channel sensing will be performed to the UE 110. The BS 170 can also send a second parameter in the same IE or another IE indicating that receiver channel sensing will be performed to the UE 110.

[0126] Within the existing CO, the BS 170 will not perform channel sensing before sending DL scheduling assignments or UL scheduling authorizations.

[0127] In addition to existing COs, the BS 170 can initiate a CO by sending a short DL burst. This excludes unicast user plane data but includes DL scheduling allocation transmissions and UL scheduling grant transmissions. After a CO is initiated, at least one transmission in the CO can be performed by the BS 170.

[0128] Transmissions from BS 170 can be considered “short control signaling”, therefore, the transmissions do not require channel sensing as otherwise required by regulations.

[0129] In cases where BS 170 initiates a transmission that is not considered a "short control signaling", BS 170 performs ( Figure 4 Step 416) Channel sensing is performed to access the channel within the bandwidth of the serving cell of UE 110. When an idle channel is sensed, BS 170 sends (step 418) a short DL burst. The channel sensing type (directional / omnidirectional) can be determined based on the first parameter. The short DL burst can be limited to a maximum duration, for example, 2*2. μ A symbol, where μ is the SCS used to send short DL bursts.

[0130] The duration spanned by the sensing slots that are sensed as idle before the short DL burst can be deterministic, for example, 8 μs according to a so-called Type 2 DL channel access procedure. Alternatively, the duration spanned by the sensing slots that are sensed as idle before the short DL burst can be random, for example, channel sensing can be performed according to a known Type 1 DL channel access procedure, where the minimum value is CWS (three sensing slots) and / or corresponds to a minimum CAPC value p.

[0131] When the expected receiver is UE 110, this scenario is a DL scenario, and the signal flow diagram for this scenario is as follows: Figure 8 As shown in the image.

[0132] UE 110 detects the reception (step 814) of the DL scheduling allocation that BS 170 has already sent (step 812). It should be understood that prior to receiving (step 814) the DL scheduling allocation, UE 110 has already received (step 804) the IE that BS 170 has already sent (step 802), and UE 110 has determined that a first parameter included in that IE indicates that channel sensing will be performed at the transmitter, and a second parameter included in the same IE or a different IE indicates that channel sensing will be performed at the receiver.

[0133] UE 110 can use spatial filters to perform (916U) directional receiver channel sensing. In one instance, the spatial filter can be associated with the PDSCH reception from BS 170. In another instance, the spatial filter can be associated with the PDCCH reception from BS 170. In yet another instance, the spatial filter can be associated with the direction from which the strongest reference signal (CSI-RS / SSB) has been received from BS 170. In yet another instance, the spatial filter is associated with the PDCCH DMRS port received from BS 170, which is determined by the QCL relationship indicated by the TCI state in the DCI assigned by the bearer DL scheduling; each TCI state indicates that the PDCCH is associated with CSI-RS, TRS, or SSB (a QCL relationship exists). The association of the spatial filter with the reception on a particular channel can depend on the QCL relationship provided to UE 110 by BS 170. Figure 8 (Not shown).

[0134] BS 170 can also indicate to UE 110 the spatial filter in the DL scheduling allocation sent in step 812. For example, BS 170 can indicate the spatial filter to UE 110 by referencing the value in the dedicated SRI field, referring to the spatial filter that UE 110 has used to send the SRS indicated by the SRI field. In another example, the spatial sensing filter is the same spatial filter that UE 110 uses to send the aperiodic SRS triggered by the SRS request field in the DL scheduling allocation.

[0135] In response to sensing (step 816U) that the channel is idle during the sensing duration, UE 110 sends (step 817) a short UL signal to BS 170 to indicate "idle channel". Alternatively, UE 110 may use a known PHY channel (e.g., PUCCH) to indicate "idle channel" to BS 170. UE 110 may use aperiodic SRS to send the short UL signal to BS 170. Alternatively, UE 110 may use PUCCH to send the short UL signal to BS 170. In either case, the transmission of the short UL signal may be scheduled by BS 170 in DL scheduling allocation. Alternatively, the transmission of the short UL signal (step 817) may be configured to begin a preset number of N symbols before BS 170 begins sending (step 818) a DL transmission burst (step 818) to initiate a CO within the serving cell bandwidth for UE 110. It is worth noting that the latter alternative is effective when the receiver initiates the CO task, but ineffective when the transmitter initiates the CO task. One possible use case for configuring a number of N symbols is when configuring DL transport in a semi-static manner, such as semi-persistent scheduling (SPS) for PDSCH.

[0136] In some respects, BS 170 can simultaneously schedule multiple DL transmission bursts to multiple UEs 110, where UEs 110 are spatially separated. In this scenario, multiple idle channel indications may be required; that is, each scheduled UE 110 may need to send an idle channel indication to BS 170 after sensing that the channel is idle. BS 170 can trigger A-SRS individually from each scheduled UE 110, for example, using the SRS request field in the corresponding DL scheduling allocation, or using a group common DCI, such as DCI format 2_3 configured with the higher-layer parameter "srs-TPC-PDCCH-Group" set to "Type B" or "Type A" and sent previously, to trigger multiple A-SRS transmissions. UEs 110 scheduled in this spatial multiplexing mode may not expect to receive the group common trigger DCI a number of M processing delay symbols prior to the start of the triggered A-SRS. In some respects, as part of the process of triggering DCI by the decoding group, UE 110 that has been addressed by the DCI scrambling group public RNTI but has not yet been scheduled in this spatial multiplexing mode can ignore the SRS request.

[0137] BS 170 detects and receives an "idle indication" sent by UE 110 (step 817). Then, BS 170 performs channel sensing (step 816B) on the channel within the bandwidth of UE 110's serving cell. In response to sensing (step 816B) that the channel is idle, BS 170 may send (step 818) a DL transmission burst to initiate CO. The channel sensing type (directional / omnidirectional) can be determined according to a first parameter.

[0138] When the expected receiver is BS 170, this scenario is a UL scenario, and the signal flow diagram for this scenario is as follows: Figure 9 As shown in the image.

[0139] UE 110 detects the reception (step 914) of the UL scheduling grant already sent by BS 170 (step 912). It should be understood that prior to receiving (step 914) the UL scheduling grant, UE 110 had already received (step 904) the IE already sent by BS 170 (step 902), and the UE had determined that a first parameter included in that IE indicates that channel sensing will be performed at the transmitter, and a second parameter included in the same IE or a different IE indicates that channel sensing will be performed at the receiver.

[0140] BS 170 can use a spatial filter to perform (step 916B) directional receiver channel sensing. In one instance, the spatial filter can be associated with PUSCH reception from UE 110; for example, BS 170 can use the same spatial filter as the CSI-RS or SSB that BS 170 uses to transmit the SRS resource index indicated by the SRI field in the UL scheduling authorization; or BS 170 can use the same spatial reception filter associated with the TPMI indicated in the UL scheduling authorization. In another instance, the spatial filter can be associated with the direction from which the strongest SRS has been received from UE 110. The association of the spatial filter with a specific UL channel / signal reception can be based on the spatial relationship information provided to UE 110 by BS 170. The association of the spatial filter with a specific UL channel reception can also be based on the most recently specified MAC-CE sent to UE 110 by BS 170.

[0141] In response to sensing (step 916B) that the channel is idle during the sensing duration, BS 170 sends (step 917) a short DL signal to UE 110 to indicate "idle channel". Alternatively, BS 170 may use a known PHY channel (e.g., PDCCH) to indicate "idle channel" to UE 110. BS 170 may use aperiodic NZP CSI-RS to send (step 917) the short DL signal to UE 110. Alternatively, BS 170 may use a scheduled PDCCH to send (step 917) the short DL signal to UE 110. In any case, the transmission of the short DL signal (step 917) may be scheduled or triggered by the UL scheduling authorization sent by BS 170 in step 901. In some respects, when UE 110 is configured with an aperiodic SRS associated with an aperiodic NZP CSI-RS resource, the presence of the associated CSI-RS is indicated by the SRS request field if the value of the SRS request field is not "00"; the CSI-RS will be located in the same time slot as the SRS request field. Alternatively, the transmission of the short DL signal (step 917) can be configured to begin a preset number of N symbols before UE 110 starts transmitting (step 918) the UL transmission burst to initiate a CO within the serving cell bandwidth of UE 110. One possible use case for configuring N symbols is when the UL transmission is semi-statically configured, such as a PUSCH transmission with a configured grant (CG) or a periodic PUCCH transmission.

[0142] In the UL scenario, UE 110 detects the reception of an "idle indication" sent from BS 170 (step 917). Then, UE 110 performs channel sensing (step 916U) on the channel within the bandwidth of its serving cell. In response to sensing (step 916U) that the channel is idle, UE 110 may send (step 918) a UL transmission burst to initiate a CO. The channel sensing type (directional / omnidirectional) can be determined based on a first parameter.

[0143] The duration of the sensing time slot span can be deterministic or random (recall the Type 1 UL / DL channel access procedure discussed earlier). The random duration used for sensing can be particularly useful for high-priority access, as explained above in the case where the receiver, rather than the transmitter, does not initiate a CO.

[0144] Receiver channel sensing can be defined as determining the level of interference, rather than simply detecting binary conditions, i.e., whether the channel is busy or idle. Receiver channel sensing can be particularly important when the interference originates from a node hidden from the transmitter's perspective. The receiver can interpret a specific level of interference, i.e., interference exceeding a threshold, as detrimental to the reception of future transmissions. When the receiver determines that the detected interference level exceeds the threshold, it can assume the channel is busy.

[0145] To determine whether harmful interference exists, the receiver can measure the interference level and compare the measured interference level with the EDT. Rx A comparison can be made. The EDT can be determined using a different formula than the one used to determine the transmitter's maximum energy detection threshold. Rx .

[0146] When UE 110 is the receiver, EDT can be determined by adding a configurable SINR offset to the RSRP threshold. Rx The value of, that is,

[0147]

[0148] When BS 170 is the receiver, EDT Rx The value can be determined at least based on the target received power P0(j) for each radio block. This value can be found in the open-loop UL PC parameters provided to UE 110 by BS 170. For P0(j), j corresponds to the value in the SRI field included in the UL scheduling grant, and for the configured grant PUSCH, j = 1.

[0149] The actual number of radio blocks allocated in the UL scheduling grant can be used to extend P0(j) by the bandwidth of a given SCS or the maximum number of radio blocks that can be allocated within an active BWP. In one example, the maximum number of radio blocks allocated in the UL scheduling grant is 275 radio blocks per component carrier.

[0150] In one example, channel sensing can be performed according to a Type 1 UL / DL channel access procedure. Recall that the value p represents a single CAPC value associated with the DL / UL transmission of the CO initiated by the shared receiver. The delay period for channel sensing can be defined as T. d =T f +m p *T sl It is worth noting that an integer number of consecutive sensing time slots m p Associated with the CAPC value p, which is related to the DL / UL transmission. Channel sensing can be performed over N consecutive random time slots. The generation of the random number N may involve selecting from the interval [0, CW]. p Select a number from the list, where CW p This represents the size (in time slots) of the contention window associated with the CAPC value p. The contention window size value is CW. p It cannot be less than three time slots; otherwise, it can be the minimum CW value configured for the CAPC value p. min,p With the maximum value CW max,p Between. That is, max{3,CW min,p}≤CW p ≤CW max,p In one example, T f =3μs,T sl =5μs,m p ≥1.

[0151] The maximum EDT used by the receiver can be calculated based on the "idle indication" transmission parameter and the maximum value of the EDT associated with the transmitter. Tx To configure. Transmission parameters associated with the transmitter can include output power P. out One or more of the following: total transmitted power, transmitter antenna gain, and transmitter bandwidth.

[0152]

[0153] Among them, P out It is the RF output power (effective isotropic radiated power, EIRP), P max It is the RF output power limit (EIRP).

[0154] The transmission duration of the transmitter is expected to not exceed the MCOT T from the COT initiated by the receiver. mcot,p .

[0155] In all aspects of this application, the duration of any transmission gap can be counted in the COT. Alternatively, the COT can only count the duration of transmission gaps less than or equal to a specific duration (e.g., 8 μs). If multiple CAPC values ​​are not defined, a common MCOT value, such as T, can be used. mcot,p =5ms.

[0156] In a second generalized aspect of this application, only the receiver performs channel sensing. In a third generalized aspect of this application, both the receiver and the transmitter can perform channel sensing.

[0157] Both of these aspects are present in common scenarios where the receiver is expected to be configured to perform channel sensing. Configuration can be accomplished via dynamic indication. Channel sensing occurs before the transmission of an "idle channel" indication, which occurs when an idle channel is sensed. Recall that sensing is performed over a sensing duration, which can be deterministic or stochastic.

[0158] The following discussion focuses on the DL scenario, where UE 110 is the intended receiver and BS 170 is the transmitter. Specifically, the focus is on the case where UE 110 sends an "idle channel" indication to BS 170 as receiver auxiliary information using an aperiodic SRS (A-SRS) triggered by BS 170 in a DL allocation DCI used to schedule one or more subsequent PDSCHs. In this case, it should be understood that in the existing mechanisms in 3GPP Rel-15 / 16, A-SRS can be triggered on pre-configured SRS resources via a non-back-off DCI format (i.e., DCI 1_1 and DCI 1_2 in the DL scheduling scenario). It is worth noting that the existing mechanisms were established for purposes other than the "idle channel" indication. Such purposes could include supporting MIMO features or "uses" (i.e., beam management, codebook transmission, non-codebook transmission, or antenna switching) or supporting positioning features.

[0159] According to the UE detection procedure in TS 38.214v16.6.0, UE 110 can be configured with one or more SRS resource sets, such as the higher-layer parameter SRS-ResourceSet or SRS-PosResourceSet (in the case of positioning). For each SRS resource set configured in SRS-ResourceSet, UE 110 can be configured with SRS resources (higher-layer parameter SRS-Resource), where the maximum value of K is indicated by UE capability. When the SRS resource set is configured with the higher-layer parameter SRS-PosResourceSet, UE 110 can be configured with K ≥ 1 SRS resources (higher-layer parameter SRS-PosResource), where the maximum value of K is 16. SRS resource set applicability or MIMO usage as described above can be configured by the higher-layer parameter usage in SRS-ResourceSet. For A-SRS, at least one state (SRS request) in the DCI field can be used to select at least one SRS resource set in the configured SRS resource sets.

[0160] Therefore, BS 170 typically triggers transmissions for all SRS resource sets configured by SRS-ResourceSet, where the value of the higher-level parameter aperiodicSRS-ResourceTrigger or the value of an entry in the higher-level parameter aperiodicSRS-ResourceTriggerList is set to the value of the SRS request field in the trigger DCI format. Furthermore, BS 170 typically triggers transmissions for all SRS resource sets configured by SRS-PosResourceSet, where the value of an entry in the higher-level parameter aperiodicSRS-ResourceTriggerList is set to the value of the SRS request field in the trigger DCI format. If the value of the SRS request field is 0, for example, if the 2 bits specified in this field represent 00, then the SRS resource set is not triggered.

[0161] Therefore, for shared spectrum access operations in the frequency range FR2-2 (60 GHz of unlicensed spectrum within the extended FR2 from 52.6 GHz to 71 GHz) or higher, a method is needed to utilize existing A-SRS triggering mechanisms for the explicit purpose of transmitting binary idle indications as receiver-assisted information. To establish appropriate conditions for the triggering mechanism, channel sensing is performed by the receiver (steps 616 and 816U). Furthermore, triggering a single A-SRS resource (steps 617 and 817) rather than a potential set of multiple SRS resources is conditional upon sensing an idle channel. Additionally, the UE 110 supporting receiver-assisted channel access should also be able to operate according to conventional A-SRS triggering mechanisms to support A-SRS-based MIMO / location features for backward compatibility.

[0162] In addition, it should be noted that in the existing configuration of the aperiodic SRS resource set, the time domain position of the aperiodic SRS resource can be provided by the higher-level parameter slotOffset, which is the offset of the number of time slots between the trigger DCI and the actual transmission of the SRS-ResourceSet. If not provided, the default value is 0.

[0163] The position of the aperiodic SRS resource in the time domain can also be provided by the higher layer parameter startPosition provided for each aperiodic SRS resource, which indicates the first symbol of the resource, found by counting backwards from the last symbol of the slot indicated by slotOffset. For an aperiodic SRS-ResourceSet, slotOffset is defined for the SRS resource set, but for an aperiodic SRS-PosResourceSet, slotOffset is defined for each aperiodic SRS resource. Assume that triggering an A-SRS transmission for providing receiver assistance information is intended to report interference conditions at the intended receiver UE 110 to the transmitter BS 170. As an idle indication, sending A-SRS should be as close as possible in the time domain to the start of the scheduled PDSCH so that the report is relevant. For example, UE 110 expects that the triggered A-SRS transmission should start at most N symbols before the start of the scheduled PDSCH. The number of symbols N can be determined based on one or more of the subcarrier spacing of the active BWP, the subcarrier spacing of the scheduled PDCCH, UE capabilities, and the UE mobility / channel model. The minimum number of symbols (<N) from the start of the A-SRS transmission to the start of the scheduled PDSCH can also be determined based on one or more of the subcarrier spacing of the active BWP, the UE's ability to meet the time requirements for switching from transmission to reception using the same or different spatial domain filters, and the BS's processing time for A-SRS. Therefore, hereinafter, the higher layer parameter slotOffset that can be specified for an aperiodic SRS resource (set) triggered to provide receiver assistance in channel access can be reinterpreted to indicate the number of slots from the actual transmission of the triggered aperiodic SRS resource (set) to the start of the scheduled PDSCH. If the parameter slotOffset is set to 0, or if the parameter is not provided, it means that if the aperiodic SRS resource is triggered, it appears in the leading symbol in the same slot as the start of the scheduled PDSCH (or the first PDSCH among the multiple scheduled PDSCHs triggered by the DCI). If the parameter slotOffset is set to 1, it means that if the aperiodic SRS resource is triggered, it appears in the slot before the slot where the scheduled PDSCH (or the first PDSCH among the multiple scheduled PDSCHs triggered by the DCI) starts. For example, instead of the traditional parameter startPosition with a value range of (0-5), a new higher layer parameter startPosition-r17 with a value range of (0-13) can be provided for this aperiodic SRS resource to increase the flexibility of the aperiodic SRS resource mapping.

[0164] In various aspects of this application, it is proposed to introduce a 1-bit flag in the non-back-off DL allocation DCI, for example, DCI format 1_1, where the CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI, and the existing SRS request field is used.

[0165] For operations using shared spectrum access in FR2-2, a 1-bit flag, such as "Channel Access SRS" or "Channel Access Indication," is added to the non-back-off DL allocation DCI format to schedule PDSCH and trigger A-SRS as an "Idle Indication" in the serving cell, so as to schedule receiver auxiliary channel access before PDSCH starts.

[0166] If a 1-bit flag is present in the DCI format and set to 1, this indicates to the intended receiver UE 110 that, upon decoding the DCI format, the SRS request field in the same DCI triggers an A-SRS transmission on the aperiodic SRS resources configured by the SRS-ResourceSet or SRS-PosResourceSet to provide receiver assistance in channel access. If the UE has sensed that the channel is idle in all sensing slots during the sensing duration, the UE 110 will perform channel sensing immediately before the indicated aperiodic SRS resources and send A-SRS. The sensing duration can be deterministic or stochastic. Sensing can be performed based on the type of channel access procedure configured for the UE 110 or based on the type of channel access procedure dynamically indicated in the same DCI. In this case, this instance of the DCI format will not trigger an aperiodic SRS resource set for MIMO use or positioning purposes.

[0167] If the 1-bit flag is present in the DCI format, but the value of the specified bit in the SRS request field (2 LSBs in the case of a 3-bit or 2-bit field in DCI 1_1, or the number of LSBs in DCI 1_2 as configured in srs-RequestDCI-1-2-r16) is set to 00 or 0, the UE ignores the 1-bit flag because the DCI does not trigger an A-SRS transmission.

[0168] If the 1-bit flag is present in the DCI format and set to 0, or if the 1-bit flag is absent, this indicates to UE 110 that the SRS request field in the same DCI triggers an aperiodic SRS resource set configured by SRS-ResourceSet or SRS-PosResourceSet for MIMO use or location purposes, respectively, based on conventional mechanisms and probe procedures.

[0169] For DCI format 1_1 with CRC scrambling by C-RNTI, CS-RNTI, or MCS-C-RNTI, a 1-bit flag may exist only if one or more of the following conditions are met. In the first case, UE 110 may be configured with higher-layer parameters indicating that channel sensing will be performed at the receiver. These higher-layer parameters may also indicate the type of receiver channel access procedure. In the second case, UE 110 may be configured with higher-layer parameters indicating that the 1-bit flag exists in DCI format 1_1, for example, that the 1-bit flag exists in the SRS-Config IE. In the third case, UE 110 may configure at least one aperiodic SRS resource set, where the higher-layer parameter usage is set to a new value, such as channelAccess or receiverAssistance. In the fourth case, UE 110 may be configured with at least one aperiodic SRS resource(set), where the new higher-layer parameters indicate that the resource(set) is configured for channel access or receiver assistance purposes.

[0170] For DCI format 1_2 scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the 1-bit flag may exist only if UE 110 is configured with the higher-layer parameter srs-RequestDCI-1-2-r16 and one or more of the following conditions are met. In the first case, UE 110 may be configured with a higher-layer parameter indicating that channel sensing will be performed at the receiver. This higher-layer parameter may also indicate the type of receiver channel access procedure. In the second case, UE 110 may be configured with at least one aperiodic SRS resource set, where the higher-layer parameter usage is set to a new value, such as channelAccess or receiverAssistance. In the third case, UE 110 may be configured with at least one aperiodic SRS resource(set), where the new higher-layer parameter indicates that the resource(set) is configured for channel access or receiver assistance purposes.

[0171] To ensure that a single aperiodic SRS resource can be conditionally triggered (e.g., triggered in response to UE 110 sensing a channel idle) when the SRS request field in the same non-back-off DL allocation DCI scheduling PDSCH is triggered for the purpose of providing receiver assistance in channel access, one or more of the following UE procedures can be applied. Conveniently, the following UE procedures allow triggering a single SRS resource within a single SRS resource set.

[0172] In the SRS resource set indicated by the SRS request field, where the value of an entry in the configured aperiodicSRS-ResourceTrigger or the configured aperiodicSRS-ResourceTriggerList is used, as described above, only the SRS resource set with the smallest SRS-ResourceSetId is considered conditionally triggered. Conversely, all other SRS resource sets indicated by the SRS request field are considered non-triggered. Within the considered SRS resource set, a single aperiodic SRS resource is configured by BS 170 for use by UE 110. Otherwise, multiple SRS resources are configured by BS 170, allowing UE 110 to select the aperiodic SRS resource with the smallest SRS-ResourceId. In some aspects of this application, only the SRS resource set with the largest SRS-ResourceSetId and the SRS resource with the largest SRS-ResourceId are considered. Alternatively, if the gNB has configured multiple SRS resources within the set of SRS resources under consideration, the BS 170 may configure only one aperiodic SRS resource, where new higher-layer parameters indicate that the resource is configured for channel access or receiver assistance purposes.

[0173] Alternatively, UE 110 can be configured with one or more aperiodic SRS resource sets. Each aperiodic SRS resource set may include a higher-level parameter usage, set to a new value, such as channelAccess or receiverAssistance. Therefore, in the SRS resource set indicated by the SRS request field using the value of an entry in the configured aperiodicSRS-ResourceTrigger or the configured aperiodicSRS-ResourceTriggerList, as described above, only the SRS resource set with the smallest SRS-ResourceSetId is considered conditionally triggered from one or more aperiodic SRS resource sets with the parameter usage configured to channelAccess or receiverAssistance. Conversely, all other SRS resource sets indicated by the SRS request field are considered not triggered. It can be specified that when the higher-level parameter usage of a given SRS resource set is set to channelAccess or receiverAssistance, at a given time or time slot, only one SRS resource in the given SRS resource set is likely to be conditionally triggered. The BS 170 configures multiple SRS resources within a given SRS resource set, enabling the UE 110 to select an aperiodic SRS resource with the smallest SRS-ResourceId. In some aspects of this application, only the SRS resource with the largest SRS-ResourceId is selected. Alternatively, if the gNB configures multiple SRS resources within the considered SRS resource set, the BS 170 may configure only one aperiodic SRS resource, where new higher-layer parameters indicate that the resource is configured for channel access or receiver assistance purposes.

[0174] In various aspects of this application, it is proposed to introduce a 2-bit field in the non-back-off DL allocation DCI, for example, DCI format 1_1, where the CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI, and A-SRS transmission is triggered using the existing SRS request field, for conventional purposes or receiver-assisted purposes or for both purposes.

[0175] For operations using shared spectrum access in FR2-2, a 2-bit field, such as an SRS trigger mode or channel access indication, can be added to the non-back-off DL allocation DCI format. This field is used to schedule PDSCH and trigger A-SRS as an idle indication in the serving cell, providing receiver assistance for channel access before PDSCH scheduling begins. The first state of the 2-bit field indicates that A-SRS transmission is triggered for receiver-assisted channel access. The second state of the 2-bit field indicates that A-SRS transmission is triggered for conventional MIMO / location purposes. The third state of the 2-bit field indicates that A-SRS transmission is triggered for both receiver-assisted channel access and conventional MIMO / location purposes. The fourth state of the 2-bit field can be reserved. Furthermore, UE 110 can be configured with one or more aperiodic SRS resource sets. Each aperiodic SRS resource set can include the higher-layer parameter "Enable SRS triggering for channel access". Therefore, enabling SRS triggering for channel access can be achieved by setting the existing higher-layer parameter usage to a new value, such as channelAccess or receiverAssistance. Alternatively, enabling SRS triggering for channel access can be achieved by providing a new higher-level parameter, such as SRS-ChannelAccess. BS 170 can configure the higher-level parameter "Enable SRS triggering for channel access" for only one SRS resource set, which includes a single SRS resource for each BWP.

[0176] If the 2-bit field is present in the DCI format and set to 01, this indicates to the intended receiver UE 110 that, when decoding the DCI format, the SRS request field in the same DCI triggers A-SRS transmission on the aperiodic SRS resources configured by SRS-ResourceSet or SRS-PosResourceSet to provide receiver assistance in channel access. In this case, using the value of the entry in the configured aperiodicSRS-ResourceTrigger or configured aperiodicSRS-ResourceTriggerList, the SRS resource set indicated by the SRS request field is considered conditionally triggered only if, as described above, the higher-level parameter "Enable SRS triggering for channel access" (e.g., SRS-ChannelAccess) is enabled. Conversely, all other SRS resource sets indicated by this SRS request field are considered untriggered; that is, no SRS resource set for MIMO / positioning is triggered.

[0177] If the UE has sensed that the channel is idle in all sensing slots during the sensing duration, the UE 110 will perform channel sensing immediately before the indicated aperiodic SRS resource and send A-SRS. The sensing duration can be deterministic or stochastic. Sensing can be performed based on the type of channel access procedure configured for the UE 110 or based on the type of channel access procedure dynamically indicated in the same DCI.

[0178] If the 2-bit field is present in the DCI format and set to 10, this indicates to the intended receiver UE 110 that, when decoding the DCI format, the SRS request field in the same DCI triggers A-SRS transmission on the aperiodic SRS resources configured by SRS-ResourceSet or SRS-PosResourceSet, for MIMO or positioning purposes, respectively. In this case, the SRS resource sets indicated by the SRS request field, using the value of the entry in the configured aperiodicSRS-ResourceTrigger or configured aperiodicSRS-ResourceTriggerList, are considered conditionally triggered only those SRS resource sets that do not have the higher-layer parameter "Enable SRS triggering for channel access" configured, i.e., no SRS resource sets for receiver assistance are triggered.

[0179] If the 2-bit field is present in the DCI format and set to 11, this indicates to the intended receiver UE 110 that, when decoding the DCI format, the SRS request field in the same DCI triggers A-SRS transmission on an aperiodic SRS resource set configured by SRS-ResourceSet or SRS-PosResourceSet, for MIMO or positioning purposes or for receiver assistance purposes, respectively. In this case, using the value of the entry in the configured aperiodicSRS-ResourceTrigger or configured aperiodicSRS-ResourceTriggerList, the SRS resource set indicated by the SRS request field is considered triggered only if, as described above, the higher-layer parameter "Enable SRS Triggering for Channel Access" is not configured. Conversely, the remaining SRS resource sets (with the higher-layer parameter configured) are considered conditionally triggered.

[0180] If the field exists in the DCI format, but the value of the specified bit of the SRS request field (2 LSB in the case of a 3-bit or 2-bit field in DCI 1_1, or the number of LSBs in DCI 1_2 as configured in srs-RequestDCI-1-2-r16) is set to 00 or 0, the UE ignores the field because the DCI does not trigger an A-SRS transmission.

[0181] If this field is not present in the DCI format, this instructs the UE 110 that the SRS request field in the same DCI triggers an aperiodic SRS resource set configured by SRS-ResourceSet or SRS-PosResourceSet for MIMO use or location purposes, respectively, based on legacy mechanisms and probe procedures. The UE 110 may not expect to configure one or more aperiodic SRS resource sets, each with the higher-layer parameter "Enable SRS triggering for channel access".

[0182] For DCI format 1_1 with CRC scrambling by C-RNTI, CS-RNTI, or MCS-C-RNTI, the 2-bit field may exist only if one or more of the following conditions are met. Under the first condition, UE 110 may be configured with higher-layer parameters indicating that channel sensing will be performed at the receiver. These higher-layer parameters may also indicate the type of receiver channel access procedure. Under the second condition, UE 110 may be configured with higher-layer parameters indicating that the 2-bit field exists in DCI format 1_1, such as in SRS-ConfigIE. Under the third condition, UE 110 may be configured with at least one aperiodic SRS resource set having the higher-layer parameter "Enable SRS triggering for channel access" (the parameter usage can be provided, which can be set to channelAccess, receiverAssistance, or a new parameter SRS-ChannelAccess). Under the fourth condition, UE 110 may be configured with at least one aperiodic SRS resource having a new higher-layer parameter indicating that the resource is configured for channel access purposes or for receiver assistance purposes.

[0183] For DCI format 1_2 scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the 2-bit field may exist only if UE 110 is configured with the higher-layer parameter srs-RequestDCI-1-2-r16 and one or more of the following conditions are met. Under the first condition, UE 110 may be configured with a higher-layer parameter indicating that channel sensing will be performed at the receiver. This higher-layer parameter may also indicate the type of receiver channel access procedure. Under the second condition, UE 110 may be configured with at least one aperiodic SRS resource set having the higher-layer parameter "Enable SRS triggering for channel access" (the parameter usage may be provided, setting it to channelAccess or receiverAssistance, or a new parameter SRS-ChannelAccess may be provided). Under the third condition, UE 110 may be configured with at least one aperiodic SRS resource having a new higher-layer parameter indicating that the resource is configured for channel access purposes or for receiver assistance purposes.

[0184] In various aspects of this application, it is proposed to introduce a separate SRS request field in the non-back-off DL allocation DCI, for example, DCI format 1_1, where the CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI to separately trigger A-SRS transmission for receiver assistance.

[0185] For operations using shared spectrum access in FR2-2, a separate SRS request field, such as a channel access SRS request, can be added to the non-backoff DL allocation DCI format. This field is used to schedule PDSCH and trigger A-SRS as an idle indication in the serving cell, providing receiver assistance for channel access before PDSCH scheduling begins. Furthermore, UE 110 can be configured with one or more aperiodic SRS resource sets. Each aperiodic SRS resource set can include the higher-layer parameter "Enable SRS triggering for channel access". Therefore, enabling SRS triggering for channel access can be achieved by setting the higher-layer parameter usage to a new value, such as channelAccess or receiverAssistance, or by providing a new higher-layer parameter, such as SRS-ChannelAccess. BS 170 can configure the higher-layer parameter "Enable SRS triggering for channel access" for only one SRS resource set, including a single SRS resource for each BWP. Therefore, the DCI format can trigger A-SRS transmissions for receiver assistance, A-SRS transmissions for traditional MIMO / location purposes, or both of the above purposes.

[0186] If the "Channel Access SRS Request" field exists in the DCI format and is set to a non-zero value, this indicates to the intended receiver UE 110 that, when decoding the DCI format, the Channel Access SRS Request field in the same DCI triggers A-SRS transmission on aperiodic SRS resources configured by SRS-ResourceSet or SRS-PosResourceSet to provide receiver assistance in channel access. In this case, using the value of an entry in the configured aperiodicSRS-ResourceTrigger or configured aperiodicSRS-ResourceTriggerList, the SRS resource set indicated by the Channel Access SRS Request field is considered conditionally triggered only if, as described above, it has the higher-level parameter "Enable SRS Triggering for Channel Access" (e.g., SRS-ChannelAccess or the parameter usage set to channelAccess or receiverAssistance). Conversely, all other SRS resource sets indicated by this SRS Request field are considered untriggered; that is, the Channel Access SRS Request field does not trigger SRS resource sets for MIMO / positioning.

[0187] If the UE has sensed that the channel is idle in all sensing slots during the sensing duration, the UE 110 will perform channel sensing immediately before the indicated aperiodic SRS resource and send A-SRS. The sensing duration can be deterministic or stochastic. The UE 110 can perform channel sensing based on the type of channel access procedure configured for the UE 110, or the UE 110 can perform channel sensing based on the type of channel access procedure dynamically indicated in the same DCI.

[0188] If the conventional SRS request field exists in the DCI format and is set to a non-zero value, this indicates to the intended receiver UE 110 that, when decoding the DCI format, the SRS request field in the same DCI triggers A-SRS transmission on the aperiodic SRS resources configured by SRS-ResourceSet or SRS-PosResourceSet, for MIMO or positioning purposes, respectively. In this case, the SRS resource sets indicated by the SRS request field, using the value of the entry in the configured aperiodicSRS-ResourceTrigger or configured aperiodicSRS-ResourceTriggerList, are considered conditionally triggered only those SRS resource sets that do not have the higher-layer parameter "Enable SRS triggering for channel access" configured, i.e., the SRS request field does not trigger SRS resource sets for receiver assistance.

[0189] If the Channel Access SRS Request field is not present in the DCI format, this instructs the UE 110 that the SRS Request field in the same DCI triggers an aperiodic SRS resource set configured by SRS-ResourceSet or SRS-PosResourceSet for MIMO use purposes based on legacy mechanisms and probe procedures, or for location purposes, respectively. The UE 110 may not wish to configure one or more aperiodic SRS resource sets, each with the higher-layer parameter "Enable SRS Triggering for Channel Access".

[0190] For DCI format 1_1 where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size can be fixed at 2 bits or 1 bit (if present). In this case, the field may exist only if one or more of the following conditions are met: In the first condition, UE 110 can be configured with higher-layer parameters indicating that channel sensing will be performed at the receiver. These higher-layer parameters may also indicate the type of receiver channel access procedure. In the second condition, UE 110 can be configured with higher-layer parameters indicating that the field exists in DCI format 1_1, such as in the SRS-Config IE. In the third condition, UE 110 can be configured with at least one aperiodic SRS resource set having the higher-layer parameter "Enable SRS triggering for channel access" (the parameter usage can be provided, setting it to channelAccess or receiverAssistance, or a new parameter SRS-ChannelAccess can be provided). In the fourth condition, UE 110 can be configured with at least one aperiodic SRS resource having new higher-layer parameters indicating that the resource is configured for channel access purposes or for receiver assistance purposes.

[0191] Alternatively, for DCI format 1_1 where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size, such as 2 bits or 1 bit, can be configured via a new higher-level parameter indicating the presence of fields in the DCI format (e.g., srs-RequestChannelAccessDCI-1-1-r17 in SRS-Config IE). In this case, the presence of fields in DCI format 1_1 can be subject to conditions similar to those in DCI format 1_2.

[0192] For DCI formats 1_2 scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size, such as 2 bits or 1 bit, can be configured via a new higher-layer parameter (e.g., srs-RequestChannelAccessDCI-1-2-r17 in SRS-Config IE) indicating the presence of the field in the DCI format. The field may exist only if the UE 110 is configured with the higher-layer parameter srs-RequestChannelAccessDCI-1-2-r17 and one or more of the following conditions are met: In the first condition, the UE 110 may be configured with a higher-layer parameter indicating that channel sensing will be performed at the receiver. This higher-layer parameter may also indicate the type of receiver channel access procedure. In the second condition, the UE 110 may be configured with at least one aperiodic SRS resource set having the higher-layer parameter "Enable SRS triggering for channel access" (the parameter usage can be provided, setting it to channelAccess or receiverAssistance, or a new parameter SRS-ChannelAccess can be provided). Under the third condition, UE 110 may be configured with at least one aperiodic SRS resource having new higher-layer parameters indicating that the resource is configured for channel access purposes or receiver assistance purposes.

[0193] In the second and third generalized aspects of this application, still considering the DL scenario where UE 110 is the intended receiver and BS 170 is the transmitter, the focus below is on the case where UE 110 uses a PUCCH scheduled by BS 170 in the DL allocation DCI for scheduling one or more subsequent PDSCHs to send an "idle channel" indication to BS 170 as receiver auxiliary information. Recall that receiver channel sensing can be defined as determining the interference level of UE 110, such as the energy measured during the sensing duration at the physical layer (L1), rather than simply detecting the binary condition, i.e., whether the channel is busy or idle. Assuming the PUCCH is a physical channel capable of carrying uplink control information (UCI) payloads, the determined interference level can also be reported to BS 170 as a UCI payload or a portion thereof. Therefore, when UE 110 detects an idle channel immediately before the indicated PUCCH resource, which occurs before the start of the PDSCH scheduled by the same DL-allocated DCI, UE 110 can send a scheduled PUCCH to indicate an idle channel with a UCI payload size of 1 bit (only in the case of binary indication) or multiple bits (e.g., 7 bits) (in the case of reporting the determined interference level).

[0194] To facilitate reporting of identified interference levels, higher layers can configure UE 110 with a new IE. This new IE provides new CSI reporting configuration parameters, such as CSI-ReportConfig-r17, including one or more of the following: report size in bits per sensed channel, a new reportQuantity, measurement duration, and an EDT threshold (below which the channel detection is idle). The new reportQuantity can be set to L1-RSSI. The report size can be set to 7 bits per sensed channel, representing a quantized value of the energy measured during the physical layer (L1) sensing duration within a dB range of [-140, -44] dB.

[0195] In this way, UE 110 can determine the size of the UCI payload sent as an idle indicator on the scheduling PUCCH, i.e., 1 bit or more bits, based on the report size provided in the new IE. Alternatively, UE 110 can determine the UCI payload size based on additional higher-layer parameters that provide the receiver auxiliary information report type (e.g., binary or measurement report).

[0196] It should be understood that the existing mechanisms in 3GPP Rel-15 / 16 can schedule PUCCHs on pre-configured PUCCH resources using non-back-off DCI formats (i.e., DCI 1_1 and DCI 1_2 in DL scheduling scenarios) to respond to PDSCH receptions scheduled by the same DCI and / or an earlier DCI, providing HARQ-ACK information in the UCI. However, it should be noted that the UCI typically refers to a combination of one or more of HARQ-ACK feedback, scheduling request (SR), and CSI. That is, the UCI bit sequence transmitted on the PUCCH can be generated solely from HARQ-ACK / SR bits, solely from CSI bits, or from both HARQ-ACK / SR bits and CSI bits. Therefore, more than one PUCCH resource set (up to four) can be configured for the UE. The higher-layer parameter simultaneousHARQ-ACK-CSI can also be provided to the UE. In this case, the UE multiplexes HARQ-ACK information with or without SR and CSI reports in the same PUCCH format 2, 3, or 4. Alternatively, if no additional simultaneousHARQ-ACK-CSI is provided, the UE discards the CSI report and includes only DLHARQ-ACK information with or without SR in the PUCCH. UE 110 typically uses the total UCI payload size to determine the applicable PUCCH resource set, and then uses the PUCCH resource indication field in the scheduling DCI to identify the indication PUCCH resources within the applicable PUCCH resource set. Each PUCCH resource is configured with at least an identifier (pucch-ResourceId), a PUCCH format (0-4), and a time-frequency resource.

[0197] Therefore, for operation in shared spectrum access in the frequency range FR2-2 or higher, a method is needed to utilize the existing PUCCH scheduling mechanism for the explicit purpose of sending an idle indication as receiver-assisted information before the start of PDSCH scheduling. To establish appropriate conditions for the scheduling mechanism, channel sensing is performed by the receiver (steps 616 and 816U). Furthermore, the transmission of the PUCCH (steps 617 and 817) is conditional upon sensing that the channel is idle. Additionally, the UE 110 supporting receiver-assisted channel access should also be able to support the new CSI report type that reuses the idle indication in the UCI reported in the PUCCH, along with other existing UCI report types, such as HARQ-ACK information. The UE 110 can determine whether to reuse the UCI report based on the configuration and timing / priority of the UCI report.

[0198] Furthermore, it should be noted that in the existing PUCCH scheduling mechanism, the time-domain position of the PUCCH resource can be dynamically indicated by the PDSCH-to-HARQ_feedback timing indication field in the DL DCI. This field is the slot-level offset from the last slot where PDSCH reception ends to the slot where the PUCCH resource is to be sent. The PDSCH-to-HARQ_feedback timing indication field value (if present) is mapped to a set of multiple slot values ​​provided by the higher-layer parameters dl-DataToUL-ACK, dl-DataToUL-ACK-r16, or dl-DataToUL-ACKForDCIFormat1_2. However, if the PDSCH-to-HARQ_feedback timing indication does not exist, the offset value is provided by dl-DataToUL-ACK, dl-DataToUL-ACK-r16, or dl-DataToUL-ACKForDCIFormat1_2. The parameter dl-DataToUL-ACK is applicable to DCI format 1_1, and dl-DataToUL-ACK-DCI-1-2 is applicable to DCI format 1_2. If dl-DataToUL-ACK-r16 is provided, UE 110 should ignore dl-DataToUL-ACK. The value -1 indicated from dl-DataToUL-ACK-r16 corresponds to a "non-numeric value" indicating that HARQ-ACK feedback timing is not explicitly included when scheduling PDSCH. In this case, it is expected that HARQ-ACK feedback will be sent in a later PUCCH resource scheduled by a later DCI, using the PDSCH-to-HARQ_feedback timing indication field (if present), or using the offset value provided by dl-DataToUL-ACK, dl-DataToUL-ACK-r16, or dl-DataToUL-ACKForDCIFormat1_2.

[0199] In various aspects of this application, it is proposed to introduce a separate new PUCCH resource indication field in the non-back-off DL allocation DCI, for example, DCI format 1_1, where the CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI, thereby separately indicating the PUCCH resource used to transmit receiver auxiliary information.

[0200] For operations using shared spectrum access in FR2-2 or later, a separate field, such as ChannelAccess-PUCCH resource indication, can be added to the non-back-off DL allocation DCI format used for scheduling PDSCH and scheduling PUCCH as idle indicators in the serving cell to provide receiver assistance for channel access before scheduling PDSCH begins.

[0201] For DCI format 1_1 where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size can be fixed at 3 bits (if present). In this case, the field may exist only if one or more of the following conditions are met: In the first condition, the UE 110 can be configured with higher-layer parameters indicating that channel sensing will be performed at the receiver. These higher-layer parameters may also indicate the type of receiver channel access procedure. In the second condition, the UE 110 can be configured with higher-layer parameters indicating that the field exists in DCI format 1_1, such as in a PUCCH-Config IE. In the third condition, the UE 110 can be configured with higher-layer parameters providing the report size in a new IE, such as CSI-ReportConfig-r17, or providing higher-layer parameters providing the receiver auxiliary information report type.

[0202] Alternatively, for DCI format 1_1 where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size can be configured to 0, 1, 2, or 3 bits via a new higher-level parameter indicating the field size in the DCI format, such as numberOfBitsForChannelAccessPUCCH-ResourceIndicatorDCI-1-1 in PUCCH-Config IE. In this case, the fields in DCI format 1_1 can have conditions similar to those in DCI format 1_2.

[0203] For DCI format 1_2 where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, the field size can be configured to 0, 1, 2, or 3 bits via a new higher-layer parameter indicating the field size in the DCI format, such as numberOfBitsForChannelAccessPUCCH-ResourceIndicatorDCI-1-2 in the PUCCH-Config IE. The field may exist only if the configured size is not 0 bits. In some aspects of this application, the field may exist only if one or more of the following additional conditions are met. Under the first condition, UE 110 may be configured with a higher-layer parameter indicating that channel sensing will be performed at the receiver. This higher-layer parameter may also indicate the type of receiver channel access procedure. Under the second condition, UE 110 may be configured with a higher-layer parameter providing the report size in a new IE, such as CSI-ReportConfig-r17, or a higher-layer parameter providing the receiver auxiliary information report type.

[0204] Recall that the purpose of scheduling PUCCH transmissions for providing receiver assistance information is to report interference conditions to the transmitter BS 170 at the intended receiver UE110. Thus, the PUCCH transmitted as an idle indication should start in the time domain as close as possible to the start of the scheduled PDSCH so that the report is relevant. For example, UE 110 expects the scheduled PUCCH transmission to start at most N symbols before the start of the scheduled PDSCH. Again, the number of symbols N can be determined based on one or more of the subcarrier spacing of the active BWP, the subcarrier spacing of the scheduled PDCCH, the UE 110 capabilities, and the UE 110 mobility / channel model. The minimum number of symbols (<N) from the start of the PUCCH transmission to the start of the scheduled PDSCH can also be determined based on one or more of the subcarrier spacing of the active BWP, the UE 110 capabilities for the time requirement of switching from transmission to reception using the same or different spatial domain filters, and the processing time of the BS for the PUCCH. <0000*********>[ <0000*********>[

[0205] Since the scheduled PUCCH transmission for providing receiver assistance information is intended to start before the start of the scheduled PDSCH reception, rather than after the end indicated by the traditional PDSCH-to-HARQ_feedback timing indication field and its associated higher layer parameters, it is also proposed to introduce a new separate timing indication field, e.g., the ChannelAccess-PUCCH-to-PDSCH timing indication in the same non-backoff DL allocation DCI. This field can have a configurable size (0, 1, or 2 bits) to indicate the slot-level offset k from the slot n of the indicated PUCCH resource to the slot n + k at the start of the scheduled PDSCH reception. The slot offset k can be selected from a specified set of numbers of slots, e.g., {0,1} or {0,1,2,3}. UE 110 can be configured, for example, in the PUCCH-Config IE with a new higher layer parameter to provide the field size in the non-backoff DL DCI format, e.g., numberOfBitsForChannelAccess-PucchToDLData-DCI-1-1 for DCI format 1_1 and numberOfBitsForChannelAccess-PucchToDLData-DCI-1-2 for DCI format 1_2. If the field does not exist, i.e., the field is configured with a 0-bit size, a default value k, e.g., 0 slots, is assumed, which means that the PUCCH resource appears in the preamble symbol of the same slot at the start of the scheduled PDSCH reception. It should be noted that for symbol-level granularity, the UE determines the PUCCH resource including its time-frequency resources based on the value of the ChannelAccess-PUCCH resource indication in the same DCI and the total UCI payload size explained above. <0000*********>[ <0000*********>[

[0206] If the ChannelAccess-PUCCH resource indication field is present in the DCI format, this instructs the intended receiver UE 110, during DCI format decoding, to schedule PUCCH transmissions on pre-configured PUCCH resources to provide receiver assistance in channel access before the start of scheduled PDSCH reception. In this case, UE 110 determines the slot n indicating the scheduled PUCCH resource based on the presence of the ChannelAccess-PUCCH-to-PDSCH timing indication field in the same DCI and the slot offset value indicated therefrom, as described above.

[0207] Regarding the determination of the total UCI payload size and the generation of the UCI bit sequence, if UE 110 determines that there is no request for HARQ-ACK information on PUCCH resources or PUSCH resources that are time-overlapping with PUCCH and scheduled to provide receiver assistance in channel access, UE 110 may determine the total UCI payload size as the configured new CSI report size, for example, 1 bit or 7 bits for energy measurement, as described above, and may generate the UCI bit sequence according to the procedure of reporting HARQ-ACK from MSB to LSB only on PUCCH. Alternatively, UE may be specified to generate the UCI bit sequence according to the procedure of reporting CSI from MSB to LSB only on PUCCH (e.g., CSI part 1). However, if UE 110 determines that it has already requested HARQ-ACK information on PUCCH resources or PUSCH resources that overlap with PUCCH in time and are scheduled to provide receiver assistance in channel access, and provides the parameter simultaneousHARQ-ACK-CSI to UE 110, then UE 110 can append new CSI report bits to the HARQ-ACK bits, for example, 1 or 7 bits of energy measurement from MSB to LSB, and can determine the total UCI payload size as the sum of the HARQ-ACK bits and the configured new CSI report size. UE 110 can then generate the UCI bit sequence according to the procedure of reporting HARQ-ACK only on PUCCH. Therefore, the applicable PUCCH resource set and PUCCH resources can be determined as described above.

[0208] If UE 110 has sensed that the channel is idle in all sensing slots during the sensing duration, UE 110 will perform channel sensing immediately before the indicated PUCCH resource and send a PUCCH. The sensing duration can be deterministic or random. UE 110 can perform channel sensing based on the type of channel access procedure configured for UE 110, or UE 110 can perform channel sensing based on the type of channel access procedure dynamically indicated in the same DCI.

[0209] If the ChannelAccess-PUCCH resource indicator field is absent in the DCI format, but the timing field ChannelAccess-PUCCH-to-PDSCH timing indicator is present in this DCI, this is indicated to the intended receiver UE 110 during DCI format decoding. This DCI format schedules PUCCH transmissions on the first PUCCH resource provided by the pucch-ResourceId obtained from the first value of the higher-layer parameter resourceList, to provide receiver assistance. The remaining process is the same as in the case where the ChannelAccess-PUCCH resource indicator field is present in the DCI, as explained above.

[0210] The following discussion focuses on the UL scenario, where BS 170 is the intended receiver and UE 110 is the transmitter. Specifically, the focus is on the situation where BS 170 uses an aperiodic NZP CSI-RS triggered by BS 170 in the UL grant DCI that schedules one or more subsequent PDSCHs to send an "idle channel" indication to UE 110 as receiver auxiliary information. It should be noted that this triggering mechanism can be applied to situations where the slot offset K2 of the scheduled PUSCH is too large for the gNB's channel sensing performed before sending the UL grant, indicating interference experienced by the gNB during the reception of the scheduled PUSCH.

[0211] In various aspects of this application, it is proposed to introduce a 2-bit field into the non-back-off DL allocation DCI, for example, DCI format 1_1, where CRC is scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI, and the existing CSI request field is used to trigger NZP aperiodic CSI-RS transmission for traditional purposes, receiver-assisted purposes, or both. For operations using shared spectrum access in FR2-2, a 2-bit field, such as a CSI-RS trigger mode or channel access indication, can be added to the non-back-off UL licensed DCI format to schedule PUSCH and trigger NZP AP-CSI-RS as an idle indication in the serving cell, providing receiver assistance for channel access before PUSCH scheduling begins. A first state indication of the 2-bit field triggers NZP AP-CSI-RS transmission for receiver-assisted channel access. A second state indication of the 2-bit field triggers NZP AP-CSI-RS transmission for traditional channel / interference measurement purposes. A third state indication of the 2-bit field triggers NZP AP-CSI-RS transmission for receiver-assisted channel access and for traditional channel / interference measurement purposes. The fourth state of the 2-bit field can be retained. Furthermore, the UE 110 can be configured with one or more aperiodic SRS resource sets. Each aperiodic CSI-RS resource set can include the higher-layer parameter "Enable NZP AP-CSI-RS Triggering for Channel Access," such as CSI-RS-ChannelAccess. The BS170 can configure the higher-layer parameter "Enable NZP AP-CSI-RS Triggering for Channel Access" for only one aperiodic CSI-RS resource set for each trigger state indicated by a CSI request in the UL authorization from the higher-layer configuration list CSI-AperiodicTriggerStateList. Assuming that for each aperiodic CSI-RS resource in the CSI-RS resource set associated with each CSI trigger state, the UE 110 is configured with a TCI state via higher-layer signaling qcl-info, i.e., the QCL configuration and QCL type of the QCL RS source, then the UE 110 can expect to trigger from the aperiodic CSI-RS resource set indicated by the CSI request field only the aperiodic CSI-RS resource configured with the same TCI state as or the TCI state of its QCL associated with receiving the PDCCH carrying the trigger UL authorization DCI.

[0212] Assuming that the triggering of NZP AP-CSI-RS transmissions to provide receiver auxiliary information is intended to report relevant interference measurements, the transmission of NZP AP-CSI-RS should be as close as possible in the time domain to the start of the scheduled PUSCH, for example, at most N symbols before the start of the scheduled PDSCH. Therefore, the UE can be configured with a time offset of a small range relative to the triggering NZP AP-CSI-RS resource set at the start of the scheduled PUSCH. In some aspects of this application, the existing higher-layer parameter aperiodicTriggeringOffset or aperiodicTriggeringOffset-r16 can be reinterpreted to indicate the number of time slots in the time slots that trigger the aperiodic CSI-RS resource set and the time slots that initiate the scheduled PUSCH transmission.

[0213] The fourth generalized aspect of this application relates to a scenario where neither the first higher-layer parameters nor the second higher-layer parameters are provided when the CC is configured to operate in millimeter-wave shared spectrum. Therefore, neither the transmitter nor the intended receiver performs channel sensing before the transmitter initiates a CO on the serving cell.

[0214] UE 110 may expect to provide some higher-level parameters in a single IE or in several different IEs. The received higher-level parameters may indicate one or more of the following types of channel access mechanisms and / or related to channel-awareness: dynamic power control / adaptive transmit power control (ATPC) channel access mechanism; adaptive duty cycle channel access mechanism; dynamic channel selection / dynamic frequency selection (DFS) channel access mechanism.

[0215] For the ATPC channel access mechanism, the received higher-layer parameters may indicate one or more of the following: ATPC periodicity, at least for DL ​​reception / channel estimation, assuming a constant transmission power level; link budget margin, within which the transmission power of the target modulation and coding scheme can be reduced; target block error rate (BLER); target SINR; etc.

[0216] For an adaptive duty cycle channel access mechanism, the received higher-layer parameters may indicate one or more of the following: channel occupancy / utilization measurement / feedback periodicity; measurement energy detection threshold; target long-term duty cycle; maximum channel occupancy time in a given frame; minimum shutdown / idle period, which can be expressed as the minimum number of consecutive slots / symbols before the start of a subsequent CO; etc.

[0217] For the DFS channel access mechanism, the received higher-layer parameters may indicate one or more of the following: channel availability assessment period; maximum interference threshold; channel handover delay; etc.

[0218] It is possible to identify one or more types of channel access mechanisms and / or potentially associated higher-layer parameters that indicate the absence of channel sensing, and to provide these higher-layer parameters to UE 110 based on UE 110’s signaling capabilities for each serving cell or each operating band.

[0219] It can be shown that the fourth generalized aspect of this application relates to scenarios where neither the first higher-layer parameters nor the second higher-layer parameters are provided. When configuring a channel access mechanism without channel sensing for a serving cell, it conveniently provides supporting parameters for potential standard impacts and relates to alternative channel access and interference mitigation techniques.

[0220] It should be understood that one or more steps of the implementation methods provided herein can be performed by corresponding units or modules. For example, data can be transmitted by a transmitting unit or transmitting module. Data can be received by a receiving unit or receiving module. Data can be processed by a processing unit or processing module. The corresponding units / modules can be hardware, software, or a combination thereof. For example, one or more units / modules can be integrated circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). It should be understood that if these modules are software, they can be retrieved by a processor, wholly or partially, individually or collectively, for processing as needed, or in one or more instances as needed, and these modules themselves can include instructions for further deployment and instantiation.

[0221] While combinations of features are shown in the illustrated embodiments, it is not necessary to combine all features to achieve the advantages of the various embodiments of the invention. In other words, a system or method designed according to embodiments of this disclosure does not necessarily include any of the features shown in the drawings or in all portions schematically illustrated in the drawings. Furthermore, selected features of one exemplary embodiment may be combined with selected features of other exemplary embodiments.

[0222] While this disclosure has been described with reference to illustrative embodiments, this description is not intended to be limiting. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of this disclosure, will become apparent to those skilled in the art upon reference to this description. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A method for operating a user equipment (UE) in a millimeter-wave shared spectrum, the method comprising: The UE receives higher-layer information, which instructs the UE to operate using the shared spectrum access in the serving cell within the millimeter-wave shared spectrum. The UE sends an uplink UL transmission burst on the channel in the serving cell, thereby initiating channel occupancy on the channel. Wherein, if the higher-layer information includes an indication of the channel access mode, the transmission is performed after channel sensing is used on the channel to determine that the channel is idle; If the indication is not present in the higher-layer information, the UE directly performs the transmission without channel sensing. The method further includes: the UE receiving at least one of spatial relationship information about the UL or downlink DL reference signal and a transmission configuration indication (TCI) state about the DL reference signal as a quasi-co-located QCL.

2. The method according to claim 1, wherein, The information received by the UE from higher layers includes: The UE receives public signaling that provides cell-specific parameters, wherein the public signaling includes the higher-layer information.

3. The method according to claim 1, wherein, The information received by the UE from higher layers includes: The UE receives dedicated signaling that provides cell-specific parameters, wherein the dedicated signaling includes the higher-layer information.

4. The method according to any one of claims 2 to 3, wherein, The UE also determines the channel sensing type to be used on the channel according to the channel access mode indicated by the indication, wherein the channel sensing type is one of directional channel sensing and omnidirectional channel sensing, and wherein the channel sensing is performed by the UE according to the channel sensing type.

5. The method according to claim 4, wherein, The UE determines the channel sensing type based on the higher-layer information.

6. The method according to claim 1, wherein, If either the spatial relationship information or the TCI state corresponds to a UL transmission in the uplink transmission burst to be sent after the channel is determined to be idle using channel sensing on the channel, the channel sensing type determined by the UE is directional channel sensing.

7. The method according to any one of claims 1 to 6, wherein, The UE is also indicated with an uplink probe reference signal resource index (SRI) corresponding to the UL transmission, and the UE uses the same spatial sensing filter as the spatial transmission filter associated with the indicated SRI to perform the channel sensing.

8. The method according to any one of claims 1 to 7, wherein, The UE is also indicated with a TCI state corresponding to the UL transmission, and the UE uses the same spatial sensing filter as the spatial receiving filter used by the UE to receive the DL reference signal associated with the indicated TCI state.

9. The method according to any one of claims 1 to 8, wherein, The UE receiving higher-layer information includes the UE receiving UE-specific signaling that includes the higher-layer information.

10. The method according to any one of claims 1 to 9, wherein, The UL transmission burst is a set of transmissions from the UE that are either gapless or have gaps such that the duration of each gap is no greater than a specific value, which is one of 3 μs and 8 μs.

11. A device configured to operate in a millimeter-wave shared spectrum, the device comprising: Memory that stores instructions; as well as The processor, by executing the instructions, causes the processor to: Receive at least one higher-level information, the higher-level information instructing the device to operate using shared spectrum access in the serving cell within the millimeter-wave shared spectrum; Transmitting an uplink UL transmission burst on a channel in the serving cell initiates channel occupancy on that channel. Wherein, if the higher-layer information includes an indication of the channel access mode, the processor uses channel sensing on the channel to determine that the channel is idle before transmitting; and If the indication is not present in the higher-layer information, the processor will directly transmit without performing channel sensing. The processor receives at least one of spatial relationship information about the UL or downlink DL reference signal and a transmission configuration indication TCI state about the DL reference signal as a quasi-co-located QCL.

12. The device according to claim 11, wherein, The instructions also cause the processor to receive public signaling that provides cell-specific parameters, including the higher-layer information.

13. The device according to claim 12, wherein, The instructions also cause the processor to receive dedicated signaling that provides cell-specific parameters, wherein the dedicated signaling includes the higher-layer information.

14. The device according to any one of claims 11 to 13, wherein, The instruction also causes the processor to determine, based on the channel access mode indicated by the instruction, a channel sensing type to be used on the channel, wherein the channel sensing type is one of directional channel sensing and omnidirectional channel sensing, and wherein the channel sensing is performed by the device according to the channel sensing type.

15. The device according to claim 14, wherein, The instruction also causes the processor to determine the channel sensing type based on the higher-level information.

16. The device according to claim 11, wherein, If either the spatial relationship information or the TCI state corresponds to a UL transmission in the uplink transmission burst to be sent after the channel is determined to be idle using channel sensing on the channel, the channel sensing type determined by the processor is directional channel sensing.

17. The device according to any one of claims 11 to 16, wherein, The instruction also causes the processor to receive an indication of an uplink probe reference signal resource index (SRI) corresponding to the UL transmission, and the instruction further causes the processor to perform the channel sensing using the same spatial sensing filter as the spatial transmit filter associated with the indicated SRI.

18. The device according to any one of claims 11 to 17, wherein, The instructions also cause the processor to receive an indication of the TCI state corresponding to the UL transmission, and the instructions also cause the processor to use the same spatial sensing filter as the spatial receiving filter used by the processor to receive the DL reference signal associated with the indicated TCI state.

19. The device according to any one of claims 11 to 18, wherein, The UL transmission burst is a set of transmissions from the device that are either gapless or have gaps such that the duration of each gap is no greater than a specific value, which is one of 3 μs and 8 μs.

20. A computer-readable storage medium storing computer-executable instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 10.

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