Channel access procedures for directional systems in unlicensed bands.

Abstract

To provide a method to reserve a directional channel, such as in an unlicensed spectrum.SOLUTION: In a method to be performed by a receiving node such as user equipment (UE) in a communication system, the receiving node receives 3000 an enhanced directional transmit request message from a transmitting node and transmits 3002 an enhanced directional transmit confirmation message using one or more first beams, with at least one first beam being directed in a first direction towards the transmitting node. Further, the receiving node transmits 3004 at least one additional enhanced directional transmit confirmation message using one or more second beams, with at least one second beam being directed in a second direction towards a potentially interfering node, the second direction being a direction different from the first direction.SELECTED DRAWING: Figure 37

Description

[Technical Field]

[0001] This document relates to channel access procedures for directional systems in unlicensed bands. [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a nonprovisional application of and claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62 / 574,548, entitled "Channel Access for Directional Systems In Unlicensed Bands," filed October 19, 2017, and U.S. Provisional Patent Application No. 62 / 689,046, entitled "Channel Access Procedures For Directional Systems In Unlicensed Bands," filed June 22, 2018, both of which are incorporated herein by reference in their entireties.

[0003] Wireless communication may need to support application requirements. Application requirements may vary. For example, applications may require low latency and may be delay-tolerant. Some applications may require high reliability. Applications may include enhanced mobile broadband (eMBB), machine-type communication (MTC), massive MTC (mMTC), and / or ultra-reliable low-latency communication (URLLC) applications. Applications may be useful in industries (e.g., automotive, health, agriculture, utilities, and / or logistics).

[0004] Wireless communications can be deployed using licensed and / or unlicensed spectrum. Unlicensed spectrum can be used for non-cellular services and / or other applications (e.g., Wi-Fi). Unlicensed spectrum is sometimes viewed by cellular operators as a complementary tool. For example, unlicensed spectrum can augment cellular operators' service offerings by meeting the high demand for broadband data. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Huawei,HiSilicon,“3GPP R1-1719841,“Coexistence and channel access for NR-based unlicensed band Operation”,”3GPP TSG RAN 91 Meeting,Nov.2017 [Non-patent document 2] European Telecommunications Standards Institute(ETSI),“EN 302 567 Broadband Radio Access Networks(BRAN)V2.1.1”,(“EN 302 567 BRAN”)Jul.2017 [Non-patent document 3] Huawei,HiSilicon,“R1-1713785,“Coexistence and channel access for NR unlicensed band operation”,”3GPP TSG RAN WG1 90 Meeting,Aug.2017 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, unlicensed spectrum may impose additional constraints on spectrum use because the unlicensed spectrum may be shared by users, who may interfere with each other. [Means for solving the problem]

[0007] SUMMARY Described herein are methods and systems for reserving directional channels in the presence of potential interfering nodes, such as in unlicensed spectrum.

[0008] According to some embodiments, a method performed by a receiving node for reserving a directional channel includes receiving a directional request-to-send (DRTS) message from a transmitting node; transmitting a directional clear-to-send (DCTS) message using one or more first beams, where at least one first beam is pointed in a first direction toward the transmitting node; determining a second direction, where the second direction is different from the first direction; and transmitting at least one additional DCTS message using one or more second beams, where at least one second beam is pointed in the second direction toward a potential interfering node. In such a method, the receiving node can be a wireless transmit / receive unit and the transmitting node can be a base station. Furthermore, the method can be performed by the receiving node for reserving a directional channel in an unlicensed spectrum.

[0009] In one example, the second direction can be determined based on information from a listen-before-talk (LBT) assessment of the directional channel. In another example, the DRTS message can include an indication of the second direction, and the second direction can be determined based on the indication in the DRTS message. In yet another example, the second direction can be determined based on directional channel measurements.

[0010] In some embodiments, the DRTS message is an enhanced DRTS (eDRTS) message and the DCTS message is an enhanced DCTS (eDCTS) message. In one example, the second direction can be determined from the eDRTS message. Furthermore, in some embodiments, the at least one additional DCTS message is an enhanced DCTS-to-Self (eDCTS-to-Self) message. The DCTS message transmitted toward the transmitting node can indicate a count of eDCTS-to-Self message transmissions performed by the receiving node.

[0011] In some embodiments, the at least one additional DCTS message includes a defer duration field that specifies the amount of time that transmission is deferred. In some embodiments, the at least one additional DCTS message indicates the remaining time that the directional channel is reserved. The at least one additional DCTS message may include the remaining time of the Maximum Channel Occupancy Time (MCOT).

[0012] In some embodiments, the at least one additional DCTS message includes multiple enhanced DCTS (eDCTS) messages. In one example, the at least one additional DCTS message can be transmitted multiple times within a maximum channel occupancy time (MCOT). In some embodiments, the method further includes receiving data from the transmitting node and periodically transmitting one or more subsequent additional DCTS messages in at least a second direction within the MCOT between receiving the data from the transmitting node. Further, in some embodiments, transmitting the at least one additional DCTS message using one or more second beams includes transmitting the at least one additional DCTS message on a different beam.

[0013] In some other embodiments, the method further includes receiving a second DRTS message from the transmitting node, and transmitting a directional rejection transmission (DDTS) message to the transmitting node in response to the second DRTS message when the receiving node detects potential directional interference. The DDTS message can be an enhanced DDTS (eDDTS) message, and the eDDTS message can identify the node transmitting the interfering signal.

[0014] In some embodiments, the number of the at least one additional DCTS message transmitted is based on at least one of (i) the number of potential interfering nodes, (ii) the power of the one or more second beams, and (iii) the width of the one or more second beams. The content of each of the DRTS, DCTS, and at least one additional DCTS message can be scrambled using a sequence common to a group of cells. In one example, the content of each of the DRTS, DCTS, and at least one additional DCTS message can be scrambled using a Cell Group Sequence (CGS) common to a group of cells.

[0015] In yet another embodiment, the method further includes the steps of: performing a first directional listen-before-talk (LBT) assessment in a direction facing the receiving node toward another node to which the receiving node intends to transmit, the other node being different from the transmitting node; determining whether a channel between the receiving node and the other node is busy based on the performed first directional LBT assessment; performing a second directional LBT assessment in a reverse direction; and determining whether an interfering signal is detected from the reverse direction to initiate transmission to the other node or to postpone transmission if an interfering signal is detected.

[0016] According to some embodiments, another method performed by a receiving node for reserving a directional channel includes receiving an enhanced directional transmission request message from a transmitting node, transmitting an enhanced directional transmission confirmation message using one or more first beams, where at least one first beam is oriented in a first direction toward the transmitting node, and transmitting at least one additional enhanced directional transmission confirmation message using one or more second beams, where at least one second beam is oriented in a second direction toward a potential interfering node, the second direction being a different direction than the first direction. Further, in some embodiments, a method is performed by a receiving node for reserving a directional channel in an unlicensed spectrum.

[0017] Other embodiments include wireless transmit / receive units, systems, and receiving nodes (e.g., having a processor and a non-transitory computer-readable medium storing instructions for execution by the processor) configured to perform the methods described herein. [Effects of the Invention]

[0018] According to the present invention, it is possible to improve yield and provide a low-cost optical module. [Brief explanation of the drawings]

[0019] [Figure 1A] 1 is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram of an exemplary wireless transmit / receive unit (WTRU) that can be used within the communication system illustrated in FIG. 1A, according to an embodiment. [Figure 1C] 1B is a system diagram of an example radio access network (RAN) and core network (CN) that can be used within the communication system of FIG. 1A according to an embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further exemplary RAN and CN that can be used within the communication system of FIG. 1A, according to an embodiment. [Figure 2A] A diagram showing an example of interference in a beam-based system using directionality-based listen-before-talk with New Radio (NR)-WiGig coexistence. [Figure 2B] A diagram showing an example of interference in a beam-based system using a directionality-based listen-before-talk (LBT) procedure with NR-NR coexistence. [Figure 3A] FIG. 1 illustrates an example of carrier sensing in LBT with interference from an access point (AP) received at a user equipment (UE). [Figure 3B] A diagram showing an example of carrier sensing in LBT where there is interference from a gNB at a station (STA) and / or from an AP at a UE. [Figure 4A] A figure showing an example of carrier sensing in LBT with interference from an AP received at a gNB. [Figure 4B]A figure showing an example of carrier sensing in LBT with interference from a UE received at a STA and / or from an AP at a gNB. [Figure 5] FIG. 1 illustrates an exemplary interference scenario using eDRTS, eDCTS, and multiple eDCTS-to-self procedures to back off an interferer according to some embodiments. [Figure 6] FIG. 1 illustrates an exemplary protection period and / or region generation according to some embodiments. [Figure 7] FIG. 1 illustrates an exemplary downlink / uplink (DL / UL) switching configuration according to some embodiments. [Figure 8] 1 is a flowchart illustrating an example of a transmission procedure according to some embodiments. [Figure 9] FIG. 1 illustrates an example DL / UL switching configuration for an NR-WiGig coexistence scenario according to some embodiments. [Figure 10] A diagram illustrating an example of forward and / or reverse link beam coverage for a non-interference scenario with NR-WiGig coexistence according to some embodiments. [Figure 11] FIG. 1 illustrates another example of a DL / UL switching configuration for an NR-WiGig coexistence scenario according to some embodiments. [Figure 12] A diagram of an example beam coverage of the forward and / or reverse link in an interference scenario from an AP to a UE in NR-WiGig coexistence according to some embodiments. [Figure 13] FIG. 1 illustrates an example DL / UL switching configuration for an NR-WiGig coexistence scenario using multiple reverse minislot transmissions at higher power to force WiGig devices to back off, according to some embodiments. [Figure 14] A diagram illustrating an example of forward and / or reverse link beam coverage for an interference scenario in NR-WiGig coexistence according to some embodiments. [Figure 15A]FIG. 1 illustrates an example of paired listen-before-talk (LBT) in a single opposite direction according to some embodiments. [Figure 15B] FIG. 1 illustrates an example of pairwise LBTs in multiple opposite directions according to some embodiments. [Figure 16] A diagram illustrating the effect of beam optimization used at the transmitting node for LBT in a single opposite direction according to some embodiments. [Figure 17A] FIG. 10 illustrates the energy detection (ED) threshold increase effect for LBT in a single opposite direction using an optimized beam shape according to some embodiments. [Figure 17B] FIG. 10 illustrates the effect of increasing the ED threshold for LBT in multiple opposing directions using predefined beams according to some embodiments. [Figure 18] FIG. 10 is an example flow diagram for adjusting parameters associated with LBT in the opposite direction according to some embodiments. [Figure 19] FIG. 10 is an example flow diagram for dynamically adjusting parameters for LBT in the opposite direction according to some embodiments. [Figure 20] FIG. 10 is an example flow diagram for adjusting LBT-based transmission strategies in opposite directions according to some embodiments. [Figure 21] FIG. 10 is an exemplary flow diagram associated with a multi-ED threshold implementation according to some embodiments. [Figure 22] 10A-10C illustrate examples of using angle of arrival estimation and varying ED thresholds for LBT in opposite directions according to some embodiments. [Figure 23] FIG. 10 is an exemplary flow diagram illustrating LBT assistance from a receiving node, according to some embodiments. [Figure 24] 10A-10C illustrate examples of beam width adjustment for LBT in opposite directions, according to some embodiments. [Figure 25A]FIG. 1 illustrates an example of LBT blocking for nodes of different radio access technologies (RATs) according to some embodiments. [Figure 25B] FIG. 1 illustrates an example of LBT blocking for nodes of the same RAT according to some embodiments. [Figure 26] FIG. 1 illustrates a scenario for LBT adjustment according to some embodiments. [Figure 27A] FIG. 1 illustrates frequency domain LBT adjustment according to some embodiments. [Figure 27B] FIG. 10 is a diagram of an example of LBT adjustment in the time domain according to some embodiments. [Figure 28A] FIG. 1 illustrates an example of omnidirectional LBT behavior according to some embodiments. [Figure 28B] FIG. 1 illustrates an example of directional LBT behavior for directional transmission / reception according to some embodiments. [Figure 29] FIG. 10 is a diagram of an omni-directional LBT over-protection detection procedure according to some embodiments. [Figure 30A] FIG. 1 illustrates an example of contention window size (CWS) adaptation in a multi-cell scenario according to some embodiments. [Figure 30B] FIG. 1 illustrates an example of contention window size (CWS) adaptation in a multi-cell scenario according to some embodiments. [Figure 31] FIG. 1 illustrates an example of downlink data transmission with eDCTS-to-self transmission according to some embodiments. [Figure 32] FIG. 10 illustrates another example of downlink data transmission with both eDCTS-to-self and uplink transmission according to some embodiments. [Figure 33] A diagram illustrating an example of eDRTS, eDCTS, and eDCTS-to-self transmission according to some embodiments. [Figure 34] A diagram illustrating example UE behavior at a non-target UE after receiving eDRTS and eDCTS from another cell according to some embodiments. [Figure 35]A diagram showing an example scenario involving directional RTS / CTS in NR-U-NR-U coexistence in the presence of an interfering node. [Figure 36] 1 is a flowchart illustrating a method for reserving a directional channel according to some embodiments. [Figure 37] 10 is a flowchart illustrating another method for reserving a directional channel according to some embodiments. [Figure 38] A diagram showing an example of a series of transmissions including eDRTS and eDCTS-to-self transmissions according to some embodiments. [Figure 39] FIG. 1 illustrates an example interference scenario diagram using eDRTS, eDCTS, and multiple eDCTS-to-self procedures in NR-U-NR-U coexistence according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0020] The entities, connections, arrangements, and the like shown in and relative to the various figures are offered by way of example, not limitation. Thus, any and all statements or other indications regarding what a particular figure shows, what a particular element or entity within a particular figure is or has, and any and all similar statements that, in isolation, decoupled from context, can be read as absolute and therefore limiting, can properly be read only if constructively preceded by language such as "in at least some embodiments." For brevity and clarity of disclosure, this implied leading language will not be repeated in the detailed description of the figures.

[0021] A detailed description of illustrative embodiments will now be provided with reference to various figures. While this description provides detailed examples of possible implementations, it should be noted that the details are intended to be illustrative and in no way limit the scope of the present application.

[0022] 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may utilize one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC).

[0023] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspot or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain situations), consumer electronics devices, and devices operating on commercial and / or industrial wireless networks. Any of the WTRUs 102a, 102b, 102c, 102d may be referred to interchangeably as a UE.

[0024] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNodeB, a Home Node B, a Home eNodeB, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0025] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, sometimes referred to as a cell (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectrum. A cell may provide coverage for a wireless service in a particular geographic area, which may be relatively constant or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, one for each sector of the cell. In an embodiment, the base station 114a may utilize multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell, e.g., beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0026] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0027] More specifically, as mentioned above, the communication system 100 may be a multiple-access system and may utilize one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, and 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​Uplink (UL) Packet Access (HSUPA).

[0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE), and / or LTE Advanced (LTE-A), and / or LTE Advanced Pro (LTE-A Pro).

[0029] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0030] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0031] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0032] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., used by drones), and a roadway. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 through the CN 106 / 115.

[0033] The RAN 104 / 113 can communicate with the CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, and 102d. The data can have various quality of service (QoS) requirements, such as different throughput, delay, error resilience, reliability, data throughput, and mobility requirements. The CN 106 / 115 can provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 can communicate directly or indirectly with other RANs that utilize the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also communicate with another RAN (not shown) that utilizes GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0034] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communications protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communications networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may utilize the same RAT as the RAN 104 / 113 or a different RAT.

[0035] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may utilize cellular-based wireless technology and with a base station 114b that may utilize IEEE 802 wireless technology.

[0036] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any subcombination of the above elements while remaining consistent with an embodiment.

[0037] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0038] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF and light signals. It will be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0039] 1B, the transmit / receive element 122 is depicted as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0040] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0041] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may obtain information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may obtain information from and store data in memory that is not physically located on the WTRU 102, such as located on a server or home computer (not shown).

[0042] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components within the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0043] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from base stations (e.g., base stations 114a, 114b) and / or may determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information using any suitable location-determination method while remaining consistent with an embodiment.

[0044] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a direction sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0045] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception)) can be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or via signal processing via a processor (e.g., a separate processor (not shown) or the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0046] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to an embodiment. As mentioned above, the RAN 104 can communicate with the WTRUs 102a, 102b, and 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 can also communicate with the CN 106.

[0047] The RAN 104 may include eNodeBs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0048] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1C, the eNodeBs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0049] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the above elements is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity different from the CN operator.

[0050] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0051] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during inter-eNodeB handover, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0052] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0053] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. Although in Figures 1A-1D the WTRU is described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may use a wired communication interface (e.g., temporary or permanent) with the communication network.

[0054] In an exemplary embodiment, the other network 112 may be a WLAN.

[0055] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic originating from outside the BSS to a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to its respective destination. Traffic between STAs within the BSS may be sent through the AP; for example, a source STA may send traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent (e.g., directly) between a source STA and a destination STA using a direct link setup (DLS). In one exemplary embodiment, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using an IBSS (e.g., all of the STAs) may communicate directly with each other. IBSS mode communication is sometimes referred to herein as "ad hoc" mode communication.

[0056] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP can transmit beacons on a fixed channel, such as a primary channel. The primary channel can be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by STAs to establish a connection with the AP. In one exemplary embodiment, for example, in an 802.11 system, carrier sense multiple access with collision avoidance (CSMA / CA) can be implemented. With CSMA / CA, STAs (e.g., every STA), including the AP, can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA can back off. Within a given BSS, only one STA (e.g., only one station) can transmit at any given time.

[0057] High-throughput (HT) STAs may use 40 MHz wide channels for communication, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0058] A Very High Throughput (VHT) STA can support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel can be formed by combining contiguous 20 MHz channels. A 160 MHz channel can be formed by combining eight contiguous 20 MHz channels or two non-contiguous 80 MHz channels, sometimes referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data can pass through a segment parser that can split the data into two streams. Separate inverse fast Fourier transform (IFFT) and time-domain processing can be performed on each stream. The streams can be mapped onto two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0059] Sub-1 GHz mode operation is supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support meter-type control / machine-type communication, such as MTC devices in macro coverage areas. MTC devices can have limited functionality, including, for example, support for a certain bandwidth and / or limited bandwidths (e.g., only support for those). MTC devices can include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0060] WLAN systems, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, that can support multiple channels and channel bandwidths include a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by a STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In the example of 802.11ah, for a STA (e.g., an MTC-type device) that supports (e.g., only supports) the 1 MHz mode, the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) setting can depend on the status of the primary channel. For example, if the primary channel is busy because a STA (that only supports 1 MHz operating mode) is transmitting to the AP, the entire available frequency band may be considered busy, even though most of the frequency band may remain idle and available.

[0061] In the United States, the available frequency bands that can be used by 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah is 6MHz to 26MHz, depending on country regulations.

[0062] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to an embodiment. As mentioned above, the RAN 113 can communicate with the WTRUs 102a, 102b, and 102c over the air interface 116 using NR radio technology. The RAN 113 can also communicate with the CN 115.

[0063] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c each may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNB 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, and 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, and 180c may implement coordinated multipoint (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0064] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or lasting for different lengths of absolute time).

[0065] The gNBs 180a, 180b, 180c can be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c can utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with / connect to gNBs 180a, 180b, 180c while also communicating with / connecting to another RAN, such as eNodeBs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0066] Each of the gNBs 180a, 180b, 180c can be associated with a particular cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b and routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c can communicate with each other over the Xn interface.

[0067] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the above elements is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity different from the CN operator.

[0068] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, and mobility management, etc. Network slicing can be used by the AMF 182a, 182b to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on Ultra-Reliable Low-Latency (URLLC) access, services relying on eMBB access, and / or services for Machine-Type Communications (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies like WiFi.

[0069] The SMFs 183a and 183b can be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b can also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b can select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b can perform other functions, such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notification. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0070] The UPFs 184a, 184b may connect to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184a, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multihoming PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0071] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may connect to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0072] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0073] The emulation device can be designed to perform one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more emulation devices can perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices can perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0074] The one or more emulation devices can perform one or more functions, including all functions, without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices can be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to perform tests of one or more components. The one or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) can be used by the emulation devices to transmit and / or receive data.

[0075] Although features and elements have been described above in particular combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein can be implemented in a computer program, software, or firmware contained in a computer-readable medium, executed by a computer and / or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0076] The operation and / or use of a cell, a transmission / reception point (TRP), and / or a carrier in an unlicensed band can be standalone. The operation and / or use of a cell, a transmission / reception point (TRP), and / or a carrier in an unlicensed band can be assisted. For example, assistance can be provided by a carrier in a licensed band and is sometimes referred to as licensed assisted access (LAA). For LAA, a licensed cell, TRP, and / or carrier can be a primary cell, TRP, and / or carrier. For LAA, a licensed cell, TRP, and / or carrier can be an anchor cell, TRP, or carrier.

[0077] A cellular system operating in an unlicensed spectrum can coexist with other users of the spectrum. The other users of the spectrum may use unlicensed technologies (e.g., Wi-Fi, WiGig, and / or other cellular operators). A cellular system operating in an unlicensed spectrum may attempt to minimize interference and / or consider fairness with other users of the spectrum. For example, a cellular system may use Listen Before Talk (LBT) and / or Clear Channel Assessment (CCA). In LBT and / or CCA, system nodes such as access points (APs), eNodeBs (eNBs), gNodeBs (gNBs), TRPs, and user equipment (UEs) may listen to a channel (e.g., a frequency band having a certain center frequency and bandwidth). This may be done before transmitting on a channel and / or before transmitting on a portion of a channel to determine whether there may be another user using the channel. Listening and / or determining use by another may include and / or be based on measurements. The measurement may include energy detection.

[0078] As used herein, LBT, CCA, and LBT / CCA may be used interchangeably. A channel may be determined to be busy, occupied, and / or in use when a measurement (e.g., of energy) is made. The determination may be based on, for example, an energy measurement that may be above or equal to a threshold. For example, when the measurement (e.g., of energy) is below a threshold, the channel may be determined to be idle, free, clear, and / or not in use.

[0079] Clear, free, idle, unoccupied, and / or not busy can be used interchangeably. Not clear, not free, not idle, occupied, and / or busy can be used interchangeably. Channel and / or operating channel can be used interchangeably. CCA fail can mean that the channel was found to be busy. CCA pass can mean that the channel was found to be clear.

[0080] A potential transmitter on the channel (e.g., a UE with a potential uplink (UL) transmission and / or an eNB with a potential downlink (DL) transmission) can evaluate and / or monitor (e.g., receive) the channel. This can be done, for example, to measure and / or determine signal presence and / or interference on the channel. This can be done, for example, prior to transmission, to determine whether the channel may be in use (e.g., busy and / or occupied) by another (e.g., another system, user, and / or signal).

[0081] A potential transmitter may compare a received signal and / or interference from a channel to a reference, e.g., as part of LBT / CCA. The reference may be (e.g., one or more) threshold levels. The comparison (e.g., between the received signal and the reference) may be used to determine whether the channel may be clear. For example, if the potential transmitter determines that the channel may be clear, the potential transmitter may transmit on the channel. For example, if the potential transmitter determines that the channel may not be clear, the potential transmitter may not transmit on the channel and may postpone and / or abandon the potential transmission.

[0082] A frame-based equipment (FBE) may refer to equipment for which the transmit / receive timing can be fixed and / or structured. A load-based equipment (LBE) may, for example, not perform LBT / CCA according to a frame structure (e.g., at a fixed and / or defined time). An LBE may, for example, perform LBT / CCA when it has data to transmit.

[0083] An equipment may refer to a node and / or device that can transmit and / or receive on a licensed or unlicensed channel. For example, an equipment may include a UE, an eNB, a gNB, a TRP, a STA, and / or an AP.

[0084] As used herein, eNB, gNB, TRP, STA, cell, base station (BS), and / or AP may be used interchangeably (e.g., nodes that can transmit and receive). An eNB, gNB, and / or TRP may be used to represent one or more gNBs, TRPs, STAs, cells, BSs, APs, and / or other nodes, such as network nodes.

[0085] A device may perform an LBT / CCA check to detect energy on the channel. This may occur before a transmission and / or before a burst of transmissions on the operating channel. The LBT / CCA time period for channel assessment may be a fixed time and / or have a minimum time. Channel Occupancy Time (COT) may be the total time during which a device may have a transmission on a given channel, e.g., without reassessing channel availability. Maximum COT (MCOT) may be the total time a device may use the operating channel for a given transmission and / or burst of transmissions. The MCOT value may be configured and / or allowed (e.g., by regulation). The MCOT value may be, for example, 4 ms and / or 10 ms. The MCOT for a device may be less than the maximum allowed value. The maximum allowed value may be set, for example, by the device manufacturer.

[0086] An idle period can be a time (e.g., a continuous period of time) during which a device may not transmit on a channel. The idle period can have a minimum requirement. The minimum requirement can be based on the COT. For example, the idle period can be 5% of the COT. The idle period can be used by a device, for example, for a current fixed frame period.

[0087] If a device determines that the operating channel is clear, for example, during and / or as a result of LBT / CCA, it can transmit on the clear channel. The transmission can be immediate.

[0088] In some embodiments, if a device determines that an operating channel is occupied, e.g., during and / or as a result of an LBT / CCA, it cannot transmit on the channel (e.g., the device cannot transmit on the channel until it performs a subsequent LBT / CCA, e.g., in which it finds the channel clear).

[0089] In some embodiments, if a device determines that an operating channel is occupied, e.g., during and / or as a result of LBT / CCA, it cannot transmit on that channel, e.g., it cannot transmit on the channel for the next fixed frame period.

[0090] An LBT / CCA may be performed after a previous LBT / CCA. For example, the previous LBT / CCA may have determined that the channel was not clear. The subsequent LBT / CCA may include a wait and / or backoff period before checking whether the channel was clear.

[0091] An LBT / CCA may be performed after a preceding LBT / CCA. For example, the preceding LBT / CCA may determine that the channel may not be clear. The subsequent LBT / CCA may include a longer period during which it is determined whether the channel may be clear and / or whether transmission can be performed thereafter.

[0092] The UE may perform CCA to determine whether the channel may be free. If the UE determines that the channel is not free, the UE may add additional backoff and / or wait time (e.g., the amount of time in the contention window). For example, if the UE determines that the channel is free, the UE may check the channel again. For example, this check may occur before the actual transmission, in which case the actual transmission may not begin immediately after the channel is determined to be free.

[0093] For example, if the UE is not within a check window (e.g., 25 μs) prior to the actual transmission, the UE may perform CCA for (e.g., at least) the check window (e.g., the time of the check window period) prior to the actual transmission. For example, if (e.g., only if) it is determined that the channel is free for (e.g., at least) a portion of the check window, the UE may transmit.

[0094] CCA can be full CCA or short CCA. Full CCA can include adding (e.g., one or more) backoff periods. For example, full CCA can be performed when the channel is determined to be busy. Short CCA can be a quick check (e.g., an energy detection check). For example, short CCA can be performed in a check window prior to the start of a transmission and / or an intended and / or planned transmission.

[0095] For example, when the UE performs CCA during a (e.g., first) subframe (SF) or symbol, the UE may perform full CCA, which can determine whether the channel is free. The UE may perform short CCA prior to actual transmission. Short CCA may be performed, for example, to recheck that the channel is still free. This may be done if there is a gap between the end of full CCA and the start of transmission.

[0096] Access, resource usage, and / or transmission on a channel, within a cell, to a cell, on a resource to a TRP and / or another node can be grant-based, allocation-based, and / or scheduler-based.

[0097] For example, a UE may transmit on (e.g., only on) a set of resources, which may be in response to and / or in accordance with a received grant and / or resource allocation, and the resources may be time resources and / or frequency resources.

[0098] The grant and / or allocation may be provided (e.g., explicitly). For example, the allocation may be provided in DL control information (DCI). The grant and / or allocation may be configured, for example, by higher layer signaling. The grant and / or allocation may be used by the UE when the UE has data to transmit.

[0099] Access, resource usage, and / or transmission on resources on a channel, within a cell, to a cell, to a TRP and / or to another node can be grant-less and / or grant-free. In this specification, grant-less and grant-free can be used interchangeably. Resources can be time resources and / or frequency resources.

[0100] For example, a UE may transmit on (e.g., a set of) resources when the UE has a transmission to make. The UE may determine and / or select a resource to transmit on from one or more resources. The resource may be, for example, a configured set of resources.

[0101] Resources may be shared and / or used by other UEs. Resources may be referred to as contention-based resources. (e.g., multiple) UE transmissions may collide when the UEs simultaneously select and transmit on the same resource.

[0102] Mechanisms can be implemented that can reduce the likelihood of collisions. For example, resource selection can be determined randomly (e.g., partially randomly). Resource selection can be a function of UE-ID. Different UEs (e.g., groups of UEs) can be configured to use different resources (e.g., sets of resources).

[0103] A mechanism may be included that allows a receiver of a grant-free transmission to identify the transmitter. For example, the transmission may include an identifier and / or a partial identifier.

[0104] An LBT procedure can be designed for an omni-based system, in which transmitted energy can propagate (e.g., equally) in (e.g., all) directions, which can be sensed, for example, by devices (e.g., all devices) present within the channel sensing range of the receiver.

[0105] Directional transmission can overcome propagation limitations in the millimeter-wave band. LBT can be performed at the transmitter using a transmit (Tx) beam. In this specification, this directional LBT is sometimes referred to as "legacy LBT." Legacy LBT in a directional system (e.g., a highly directional system) can result in an increase in the number of hidden nodes (e.g., the directional hidden node problem).

[0106] In a directional system (e.g., a highly directional system), the signal energy for a transmission can be concentrated in a spatial region (e.g., a narrow spatial region) covered by the transmitted beam. A device located within the region of the transmitted beam can sense the presence of the transmission. A device located outside the region of the transmitted beam may not be able to sense the transmission. A device can sense the channel as clear to transmit. A device can initiate a transmission, but it may interfere with and / or collide with an ongoing transmission.

[0107] According to some embodiments, a clear channel assessment (CCA) can include a directional highly directional request to transmit / highly directional clear to transmit (eDRTS / eDCTS). The eDRTS message can be transmitted, for example, on multiple adjacent beams or on a wider beam. Transmissions can be enabled and / or configured based on quality of service (QoS) requirements. Enhanced signaling can be performed in the eDRTS / eDCTS message. Multiple parallel eDRTS / eDCTS messages can be transmitted on different beam pair links (BPLs) (e.g., for non-reciprocal beams). For example, eDCTS messages, such as eDCTS-to-Self messages, can be used to achieve greater spatial interference protection. In some embodiments, the eDCTS-to-Self message can be configured differently from the eDCTS message. For example, successful eDRTS and eDCTS transmissions can be followed by multiple eDCTS-to-Self transmissions. Multiple eDCTS-to-self transmissions can be transmitted on multiple beams, and a dynamic downlink / uplink (DL / UL) switching configuration can be used, which can prevent other devices' transmissions from interfering with the ongoing transmission.

[0108] According to some embodiments, an implementation of directional new radio (NR)-WiGig system coexistence in unlicensed bands can be performed. The DL / UL switching configuration for the NR link can be determined based on the minimum distributed inter-frame spacing (DIFS) duration in the WiGig system. Transmissions can be configured to be performed in the reverse direction for each window (e.g., DIFS period). Multiple block transmissions can be transmitted in the reverse direction. The transmit power of the transmissions can be increased.

[0109] According to some embodiments, listen-before-talk (LBT) can be performed in paired directions (e.g., toward the receiver and in the opposite direction). This can reduce the number of hidden nodes that can interfere with the ongoing transmission. LBT parameters (e.g., bandwidth, energy detection (ED) threshold) can be configured to reduce the number of hidden nodes that can interfere with the ongoing transmission. The transmit and receive strategy can be determined based on a function of the power / energy sensed during the LBT.

[0110] FIG. 2A illustrates an example of interference in a beam-based system using directionality-based listen-before-talk (LBT) with New Radio (NR)-WiGig coexistence. For example, as shown in FIG. 2A, NR and / or WiGig nodes may be co-located. More specifically, an NR UE 200 and a WiGig station (STA) 202 may have a packet to transmit to an NR gNB 204 and / or a WiGig access point (AP) 206, respectively. The UE 200 may initiate its transmission to the gNB 204. The STA 202 may not sense the UE's transmission to the gNB 204 (e.g., a directional hidden node problem). The STA 202 may find the channel clear and / or initiate its transmission to the AP 206. The transmission may interfere and / or collide with the UE's transmission at the gNB 204. 2B illustrates an example of interference in a beam-based system using a directionality-based listen-before-talk (LBT) procedure with NR-NR coexistence. As seen in FIG. 2B, a similar situation can occur in NR-NR coexistence when there may be no coordination between two NR systems. In FIG. 2B, one NR system may include, for example, UE 208 (also referred to as "UE1") and / or gNB 210 (also referred to as "gNB1"), and another NR system may include, for example, UE 212 (also referred to as "UE2") and / or gNB 214 (also referred to as "gNB2").

[0111] 3A and 3B illustrate another example of the hidden node problem. Fig. 3A illustrates an example of carrier sensing in LBT with interference from an access point (AP) received at a user equipment (UE). Fig. 3B illustrates an example of carrier sensing in LBT with interference from a gNB at a station (STA) and / or from an access point (AP) at a UE.

[0112] Referring to FIG. 3A, a receiving node may be interfered with by the AP 300 even if the receiving node is within the coverage area of ​​the AP 300 and / or legacy LBT at the transmitting node senses that the channel toward the receiving node is idle. The interference may be due to the directional hidden node problem. This may occur, for example, when an AP transmission is within the antenna boresight of the receiving node's receive beam but cannot be detected by the directional LBT at the transmitting node. This can be seen in FIG. 3A by the dotted line 302. As seen in FIG. 3A, this may occur, for example, when the gNB 304 is the transmitting node and the UE 306 is the receiving node.

[0113] The AP 300 can transmit (e.g., in a directional manner) toward the STA 308. The transmitting node (e.g., the gNB 304 in FIG. 3A) can perform LBT using a beam that forms a straight line toward the direction of the receiver (e.g., the UE 306 in FIG. 3A). This can be done before accessing the unlicensed channel. For example, if the STA 308 is located between the AP 300 and the transmitting node (e.g., FIG. 3A), the transmitting node can sense the channel as idle and can begin data transmission (e.g., toward the receiver). Interference from the AP 300 can be received at the UE receiver, which may be due to the directional hidden node problem. For example, if the STA 308 is located between the gNB 304 as the transmitting node and the UE receiver and / or the STA 308 is not sensed by legacy LBT (e.g., FIG. 3B), interference can be received at the STA 308.

[0114] 3A and 3B illustrate an example of carrier sensing, for example, in legacy LBT (e.g., DL access, gNB to UE). The gNB 304 may perform LBT using a beam that forms a straight line toward the UE 306. The gNB 304 may sense that the channel is idle. This may occur, for example, when the AP 300 transmits data toward the STA 308 and the gNB 304 begins transmitting data toward the UE 306. As seen in FIG. 3A, interference from the AP 300 may be received at the UE 306. As seen in FIG. 3B, if the gNB 304 does not hear the STA 308, interference from the gNB 304 at the STA 308 and / or interference from the AP 300 at the UE 306 may be received.

[0115] In another example, interference problems due to directional hidden nodes may occur when the transmitting node is, for example, a UE and the receiving node is, for example, a gNB. Figure 4A illustrates an example of carrier sensing in LBT with interference from an AP received at a gNB. Figure 4B illustrates an example of carrier sensing in LBT with interference from a UE received at a STA and / or from an AP at a gNB.

[0116] 4A and 4B illustrate an example of carrier sensing, for example, in legacy LBT (UL access, UE to gNB), which may result in interference. UE 400 may perform LBT using a beam that is direct toward gNB 402 and may sense that the channel is idle. This may occur, for example, when AP 404 is transmitting data toward STA 406. Thus, UE 400 may begin transmitting data toward gNB 402. As seen in FIG. 4A, interference from AP 404 may be received at gNB 402. As seen in FIG. 4B, STA 406 may not be heard at UE 400, and / or interference from UE 400 at STA 406 and / or from AP 404 at gNB 402 may be received.

[0117] In some embodiments, implementations may be provided that are related to the coexistence of directional NR-NR systems in unlicensed bands.

[0118] A UE / gNB may perform CCA on granted and / or scheduled resources, for example, using (e.g., one or more) beams and / or beam pair links (BPLs). Generally, in some embodiments, as used herein, a "BPL" refers to a pair of beams (e.g., a reciprocal beam (pair)) that establishes a communication link between a transmitting node and a receiving node. For example, when a transmitting node (e.g., a UE / gNB) performs CCA, it may use an Rx (receive) beam. For example, CCA may be determined based on the Rx beam that the UE / gNB used for beam pairing.

[0119] In some embodiments, after a successful determination that the channel is clear, e.g., based on a CCA and / or LBT assessment of the channel, the transmitting node and receiving node can engage in communications including enhanced signaling or messaging. Generally, the enhanced signaling / messaging can facilitate or enable performing various functions described herein. In some embodiments, the enhanced signaling / messaging can take the form of (1) an enhanced directional transmit request message, e.g., configured by the transmitting node to request a transmission on the (directional) channel and / or configured for channel reservation purposes, and (2) an enhanced directional transmit confirmation message, e.g., configured by the receiving node to confirm or acknowledge that the channel is clear for a transmission (e.g., a transmission requested by the transmitting node) and / or configured for channel reservation purposes.

[0120] As described in more detail, in some illustrative embodiments, the highly directional transmission request message can be a highly directional Request-to-Send (eDRTS) message, and the highly directional transmission confirmation message can be a highly directional Clear-to-Send (eDCTS) message and / or a highly directional Clear-to-Send-to-Self (eDCTS-to-Self) message.

[0121] Furthermore, in general, any type or kind of enhanced message described herein refers to a message that may have, e.g., enhanced message content, to facilitate or enable various functionality described herein. The enhanced message content may take the form of, e.g., one or more additional fields that provide information that enables or facilitates performance of various functions described herein. In some embodiments, the information may include, e.g., information regarding potential interfering nodes (e.g., interfering nodes known to interfere, or at least nodes that may interfere) for transmissions between the transmitting node and the receiving node, timing or scheduling information, interference direction, etc.

[0122] By way of example, in some embodiments, if a UE / gNB determines that the channel is clear on an Rx beam, it may (e.g., initially) transmit a highly directional transmission request (eDRTS) to reserve the channel and / or obtain an acknowledgment from the receiving node (e.g., gNB / UE). The Rx beam may correspond to a Tx beam on which the UE / gNB may transmit. The transmitting node (e.g., UE / gNB) may not transmit if it determines that the channel is not clear. Transmission of the eDRTS may be beam-based. The receiving node may transmit a highly directional clear-to-send (eDCTS) to the transmitter. The eDCTS may be transmitted after receiving (e.g., successfully receiving) the eDRTS. Transmission of the eDCTS may be beam-based. After the eDRTS and / or eDCTS transmission, further transmissions between the transmitting node (e.g., a gNB or a UE) and the receiving node (e.g., a UE or a gNB) may be configured.

[0123] For example, a transmission can be configured such that other transmissions from other devices that may interfere with the transmission between the transmitting node and the receiving node cannot be initiated. Such DL / UL switching configuration can be performed through an eDRTS (Advanced Directive Request to Send) message and / or an eDCTS (Advanced Directive Clear to Send) message. A transmitting node cannot initiate its transmission, for example, if it does not receive an eDCTS from the receiving node (e.g., within a configurable amount of time). For example, upon transmitting an eDRTS, the transmitting node can start a timer. For example, if it does not receive an eDCTS before the expiration of the timer, the transmitting node can consider the CCA procedure unsuccessful.

[0124] It should be noted that, as used herein, in some embodiments, DL / UL switching configuration, or DL / UL switching configuration, generally refers to a configuration that can provide information regarding, for example, message timing / scheduling, signaling / messaging type, etc., for uplink transmissions, downlink transmissions, and / or switching between uplink and downlink transmissions (switching) within a maximum channel occupancy time (MCOT) allowed for transmissions.

[0125] Furthermore, as a general matter, beams are typically used in directional systems to define spatial domain resources. Generally, each beam has its own identification information (e.g., a beam ID, which can be implicit or can be linked with other reference signal IDs) and its own spatial parameters (e.g., a phase shift to achieve the beam's direction, a beam width, an antenna gain, etc.). These spatial parameters are typically applied to enable transmission / reception in the direction corresponding to that beam. Furthermore, transmitting / receiving nodes performing directional communication between each other can perform directional transmission (e.g., determine the direction to be used for transmission) using a beam ID type identification. By way of example, NR (New Radio), for example, utilizes a beam management procedure through which a UE can dynamically report to a gNB, for example, the best transmit (Tx) beam / beam ID (e.g., from the UE's perspective) for transmission to that UE. The gNB can then transmit any data addressed to the UE using that Tx beam.

[0126] If a transmitting node (e.g., UE / gNB) successfully performs CCA on an Rx beam, it can determine a Tx beam for transmitting the eDRTS. One or more of the following can be applied: The UE / gNB can transmit the eDRTS on a Tx beam corresponding to the Rx beam on which the CCA was successful; The UE / gNB can transmit the eDRTS on a beam wider than the Tx beam corresponding to the Rx beam on which the CCA was successful; The wider beam can be centered along the same beam direction as the Rx beam on which it performed the successful CCA; The UE / gNB can transmit the eDRTS on multiple adjacent beams around the Tx beam that can correspond to the Rx beam on which the CCA was successful; The multiple adjacent beams can be selected such that the central beam is the Tx beam corresponding to the Rx beam on which the CCA was successful.

[0127] The transmitting node may transmit the eDRTS on the wider beam and / or adjacent beams, for example, to reserve the channel in a larger area around the UE / gNB receiver. Transmission of the eDRTS on the wider beam and / or adjacent beams may be enabled and / or disabled. For example, transmission may be enabled and / or disabled based on QoS requirements and / or channel quality (e.g., the SNR on the Rx beam on which successful CCA was performed). For example, if the SNR on the Rx beam on which successful CCA was performed falls below a certain (e.g., required) SNR quality (e.g., ), adjacent beam transmission may be enabled. For example, if the QoS requirements of the transmitted data may be high (e.g., above a threshold), adjacent beam transmission may be enabled.

[0128] According to some embodiments, an eDRTS message on a Tx beam corresponding to an Rx beam on which the transmitting node was able to perform successful CCA (e.g., from the transmitting node's perspective) may include one or more of the example information indications in Table 1. Regarding the content of the eDRTS message shown in Table 1, in some embodiments, the "Transmitter Identification" field and the "Receiver Identification" field may be used by other nodes to indirectly infer the direction of an upcoming transmission (e.g., the ID field may indirectly correspond to such a direction). Furthermore, the receiver identification may be used by other nodes to determine whether they are the intended recipient of a given transmission. If not, such nodes may know that they are not supposed to respond to the eDRTS message with an eDCTS message.

[0129] [Table 1]

[0130] It will be understood that, as with the other types of enhanced messages described herein, the information provided is an example of what an enhanced message may include, according to some embodiments. In the case of an eDRTS message, the eDRTS message may be configured, according to some embodiments, with a subset (e.g., a different subset) of the example information in Table 1. For example, if a UE transmits an eDRTS when it does not have granted resources, it may include in the eDRTS a transmitter identification, a receiver identification, an eDCTS flag, QoS, and / or buffer status.

[0131] The eDRTS message may be transmitted on adjacent beams (e.g., to reserve the channel in a wider area around the receiving node). On adjacent beams, the eDRTS may include, e.g., if known, the duration of the overall transmission and / or the types of control signal transmissions that may be transmitted from the transmitting node on those beams during the transmission. The control signal transmissions may be (e.g., at least one of) a reference signal (RS), e.g., a cell-specific reference signal (CRS), a sequence of bits (e.g., a specific sequence), a discovery reference signal (DRS), which may include (e.g., one or more) synchronization signals and / or reference signals.

[0132] The eDRTS can indicate the control channel resource set (CORESET) and / or the bandwidth part (BWP) of the channel. The indication can be implicit (e.g., related to the resources on which the eDRTS can be transmitted) or explicit (e.g., included as an information element within the eDRTS). This can enable the UE to determine where to look for control information that can allocate DL and / or UL resources for transmissions to be performed in the next channel occupancy period.

[0133] After decoding the eDRTS (e.g., successful decoding), the receiving node may transmit a beam-based eDCTS to the transmitting node, for example, if the eDCTS flag is set. A Tx beam on which the eDCTS will be transmitted may be selected. One or more of the following may apply: The receiving node may transmit the eDCTS on a Tx beam corresponding to the Rx beam on which the eDRTS was received. The receiving node may transmit the eDCTS on a wider beam compared to the Tx beam corresponding to the Rx beam on which the eDRTS was received. The wider beam may be centered along the same beam direction as the Rx beam on which it received the eDRTS. The receiving node may transmit the eDCTS on adjacent beams around the Tx beam corresponding to the Rx beam on which the eDRTS was received. Multiple adjacent beams may be selected; for example, the center beam may be the Tx beam corresponding to the Rx beam on which the eDRTS was received.

[0134] A node may transmit an eDCTS on a wider beam and / or an adjacent beam (e.g., to secure a channel in a larger area around the transmitting node). Transmission of an eDCTS on a wider beam and / or an adjacent beam may be enabled and / or disabled based on QoS requirements and / or channel quality (e.g., the SNR on the Rx beam on which the eDRTS was received). For example, if the SNR on the Rx beam on which the eDRTS was received is below a certain (e.g., required) SNR quality (for example), adjacent beam transmission may be enabled. If the QoS requirements of the transmitted data may be high (e.g., above a threshold), adjacent beam transmission may be enabled.

[0135] The receiving node can communicate co-channel interference that can be measured while receiving the eDRTS to the transmitting node, for example, in an eDCTS message. This can be done, for example, when background directional interference can be weak. For example, when the transmitting node (e.g., gNB / UE) can overcome the background directional interference by adjusting transmission parameters. This can be indicated by (e.g., one or more) alternative parameters. For example, the parameters can include the observed interference power, the measured signal-to-noise-and-interference power (SINR) upon reception of the eDRTS, and / or the requested modulation and coding scheme (MCS), etc.

[0136] According to some embodiments, an eDCTS message on a Tx beam corresponding to an Rx beam on which the eDRTS was received (e.g., from the perspective of the receiving node) may include one or more of the example information in Table 2.

[0137] [Table 2]

[0138] It will be understood that, as with the other types of enhanced messages described herein, the information provided is an example of what an enhanced message may include, according to some embodiments. In the case of an eDCTS message, the eDCTS message may be configured, according to some embodiments, with a subset (e.g., a different subset) of the example information in Table 2. For example, if the UE transmits an eDCTS after receiving an eDRTS from a gNB with a DL / UL switching configuration and / or signal type, the UE may include in the eDCTS the remaining duration of the overall transmission, a transmitter identification, and / or a receiver identification.

[0139] The eDCTS message may be transmitted on an adjacent beam (e.g., to reserve the channel in a wider area around the UE / gNB transmitter). The eDCTS of the adjacent beam may include the remaining duration of the overall transmission and / or the type of control signal transmission that may be transmitted from the UE / gNB on the corresponding beam during the transmission. The control signal transmission may be or include (e.g., be or include at least one of) a reference signal (RS), e.g., a cell-specific reference signal (CRS), a sequence of bits (e.g., a specific sequence), a discovery reference signal (DRS), which may include (e.g., one or more) synchronization and / or reference signals, and / or system information.

[0140] A node transmitting an eDCTS may, for example, perform (e.g., first perform) LBT and / or CCA to determine whether the channel is clear before transmitting the eDCTS. This may be a full LBT or a short LBT. A short LBT may be achieved, for example, by using a single energy detection (ED) measurement and / or a specific threshold. A node may perform (e.g., may be required to perform) LBT, CCA, and / or ED on (e.g., some and / or all) beams on which it may intend to transmit an eDCTS.

[0141] A non-reciprocal beam (and / or beam pair link) may be used for transmission and / or reception between a UE / gNB (e.g., a pair). A first node may perform an LBT to determine the availability of a BPL, e.g., for transmission from the first node to a second node. For example, if the LBT is successful, the first node may initiate an eDRTS procedure toward the second node. The second node may, e.g., transmit an eDCTS upon receiving the eDRTS transmission. The second node may, e.g., initiate an LBT procedure (e.g., a second LBT procedure) on the second BPL to enable the second node to transmit toward the first node. This may be done upon receiving the eDRTS transmission. For example, if the LBT is successful, the second node may transmit a second eDRTS toward the first node using a beam associated with the second BPL. The transmission of the second eDRTS may be simultaneous with the transmission of the first eDCTS. The first node may, for example, upon receiving the second eDRTS, transmit a second eDCTS to the second node. After completion of multiple parallel eDRTS-eDCTS procedures, for example, two BPLs may be considered available. This may be performed, for example, using a short LBT to switch between the two BPLs.

[0142] A receiving node receiving an eDRTS from another node (e.g., a gNB / UE) can respond with an advanced directional deny-to-send (eDDTS), which can be based on one or more of the following: For example, the receiving node detecting the presence of directional interference while receiving the eDRTS. The signal strength of the directional interference may be insufficient, which may cause the UE / gNB to fail to correctly detect the eDRTS intended for it. A gNB receiving an eDRTS from a UE can respond with an eDDTS if the requested transmission duration in the eDRTS overlaps with a previously scheduled transmission.

[0143] According to some embodiments, an eDDTS message on a Tx beam that may correspond to an Rx beam on which the eDRTS was received (e.g., from the perspective of the receiving node) may include one or more of the example information in Table 3.

[0144] [Table 3]

[0145] It will be understood that, as with the other types of advanced (enhanced) messages described herein, the information provided is an example of what an advanced message may include, according to some embodiments. In the case of an eDDTS message, the eDDTS message may, in some embodiments, be configured using a subset (e.g., a different subset) of the example information in Table 3. For example, when a UE / gNB transmits an eDDTS in response to observed directional interference but the interfering transmitter and / or receiver identifiers are not known, the eDDTS may include (e.g., only) the transmitter identification field and / or the receiver identification field. For example, when an eDDTS is transmitted in response to an observed eDRTS and / or an eDCTS is transmitted between an interfering pair of directional devices, the eDDTS may include (e.g., all) the fields listed in Table 3.

[0146] A transmitting node (e.g., gNB) or a receiving node (e.g., UE) can transmit a highly directional clear-to-send (eDCTS) to itself or a highly directional clear-to-send-to-self (eDCTS-to-self) to, for example, reserve a directional channel for (e.g., planned) directional transmission with (e.g., one or more) respective receiving nodes (e.g., UEs) or transmitting nodes (e.g., gNBs). An eDCTS-to-self transmission may or may not be preceded by an eDRTS transmission or reception. In some embodiments, an eDCTS-to-self message can be, for example, an eDCTS message sent by a receiving node to itself. In some embodiments, an eDCTS-to-self message can be configured to differ from an eDCTS message, for example, to have one or more different fields, format, or information.

[0147] A transmitting node (e.g., gNB) can select a Tx beam for eDCTS-to-self transmission, for example, after successfully completing CCA on a beam that the transmitting node (e.g., gNB) intends to use for a data transmission to a receiving node (e.g., UE). This can occur when the transmitting node (e.g., gNB) transmits eDCTS-to-self on a Tx beam that it identified to use for a (e.g., subsequent) downlink data transmission to the receiving node (e.g., UE). This can occur when the transmitting node (e.g., gNB) transmits eDCTS-to-self on a beam that is wider than the Tx beam associated with the subsequent downlink data transmission to the receiving node (e.g., UE). The wider beam can be centered along the same beam direction as the Tx beam that can be associated with the downlink data transmission to the receiving node (e.g., UE). This can occur when the transmitting node (e.g., gNB) transmits eDCTS-to-self on an adjacent beam. The adjacent beams can be around the Tx beam intended for the subsequent downlink data transmission. The adjacent beams can be selected such that the center beam is the Tx beam associated with a subsequent downlink data transmission to a receiving node (e.g., a UE).

[0148] A node may transmit eDCTS-to-self on a wider beam and / or an adjacent beam (e.g., to reserve the channel in a larger area around the transmitter). Transmission of eDCTS-to-self on a wider beam and / or an adjacent beam may be enabled and / or disabled based on, for example, QoS requirements, and / or channel quality, and / or historical directional interference information, etc. For example, if a known potential interferer can be associated with an adjacent beam, adjacent beam transmission may be enabled. If the QoS requirements of the transmitted data are high (e.g., above a threshold), adjacent beam transmission may be enabled. According to some embodiments, an eDCTS-to-self message may include one or more of the example information in Table 4.

[0149] [Table 4]

[0150] In some embodiments, a transmitter node (e.g., gNB) and / or a receiver node (e.g., UE) can set up a protected period for directional transmissions. This can be done by exchanging eDRTS and / or eDCTS. This exchange can be followed by, e.g., multiple eDCTS-to-self transmissions, e.g., on multiple beams, e.g., to achieve greater spatial interference protection.

[0151] FIG. 5 illustrates an exemplary interference scenario using eDRTS, eDCTS, and multiple eDCTS-to-self procedures 500 to cause interferers to back off, according to some embodiments. In the example of FIG. 5, nodes 501, 502, and 504 (also referred to as “N1, N2, and N3”) may be nodes that may cause interference to a UE 506, for example. The interference may be due to a directional antenna pattern (e.g., a highly directional antenna pattern). Nodes 508 and 510 (also referred to as “N4 and N5”) may cause interference to a gNB 512, for example, which may be due to a directional antenna pattern (e.g., a highly directional antenna pattern). As shown in FIG. 5, the gNB 512 may transmit an eDRTS 514 to the UE 506. After receiving the eDRTS 514, the UE 506 may transmit an eDCTS 516 to the gNB 512. Generally, this exchange may be followed by gNB 512 transmitting multiple eDCTS-to-self messages 518-522 on corresponding beams toward interfering nodes 501-504, respectively, and UE 506 transmitting multiple respective eDCTS-to-self messages 524, 526 on corresponding beams toward interfering nodes 508, 510, respectively, creating greater spatial interference.

[0152] 6 illustrates an exemplary protection period and / or region generation 600 according to some embodiments. In the example shown in FIG. 6, a transmitting node (e.g., a gNB) may transmit “M” eDCTS-to-self messages 604 after successfully decoding an eDCTS 602. This may be done, for example, to generate a “protection zone” for nodes that may interfere with the receiving node (e.g., UE). The transmitting node may convey the number “M” of eDCTS-to-self messages 604 in the eDRTS 601 to inform the receiving node, for example, that “M” eDCTS-to-self messages may follow after successfully decoding the eDCTS.

[0153] A receiving node (e.g., a UE) may transmit "N" eDCTS-to-self messages 606 after the eDCTS message 602. This may be done, for example, to create a "protection zone" for nodes that interfere (or may interfere) with the gNB. The receiving node may convey in the eDCTS message 602 the number "N" of eDCTS-to-self messages that may follow its eDCTS message 602. This may be done, for example, to inform the transmitting node (e.g., a gNB) of the number "N" of eDCTS-to-self messages that may follow the eDCTS message 602.

[0154] As shown in FIG. 6, control and / or data transfer 608 (DL and / or UL) between the transmitting node and the receiving node may begin, for example, after the last eDCTS-to-self message is sent by the transmitting node and / or the receiving node.

[0155] The number of eDCTS-to-self messages (M and N) transmitted by the transmitting and receiving nodes can be optimized. For example, the optimization can be based on, for example, the number of interferers and / or the power and / or width of the beam used for transmitting the eDCTS-to-self messages. This can cause the interferers to back off.

[0156] The timeline shown in FIG. 6 can be updated to reflect device capabilities. For example, a gNB can have (e.g., two) simultaneous beam processing capabilities. The gNB can receive an eDCTS message from a UE using one beam and may have already begun transmitting an eDCTS-to-self message along with (e.g., simultaneously with) an eDRTS. DL / UL exchange initiation can be moved to the Nth eDCTS-to-self message. As shown in FIG. 6, DL / UL exchange initiation can follow the last eDCTS-to-self message, which can be used by the transmitting node and / or the receiving node.

[0157] In some embodiments, DL and / or UL transmissions can be performed, for example, after reception (e.g., successful reception) of the eDCTS at the transmitting node. The UE / gNB can hold the channel in the DL and / or UL direction. This can be done, for example, so that other devices whose transmissions may interfere with the ongoing transmission cannot initiate packet transmissions. The other devices can find the channel busy (e.g., after sensing the channel with DL or / and UL transmissions) and / or not initiate their transmissions.

[0158] The DL / UL switching configuration can be determined per BPL. For example, this determination can be made at the UE / gNB transmitter and / or the UE / gNB receiver. For example, when the gNB has data to transmit to the UE, it can derive the DL / UL switching configuration and / or send it in the eDRTS. For example, if the UE does not have (e.g., any) granted resources and / or may have data to transmit to the gNB, it can send (e.g., transmit first) the eDRTS to the gNB. This can be performed without any DL / UL switching configuration. The gNB can derive the DL / UL switching configuration and / or send it to the UE in the eDCTS.

[0159] The DL / UL switching configuration can be derived based on QoS requirements and / or a minimum LBT duration. For example, for data transmission (e.g., high-reliability data transmission), transmissions in either direction between the UE / gNB transmitter and the UE / gNB receiver can be transmitted within a minimum LBT duration. This can be done, for example, to prevent other devices from finding a free channel during transmission.

[0160] FIG. 7 illustrates an exemplary downlink / uplink (DL / UL) switching configuration 700, according to some embodiments. As seen in FIG. 7 , a transmitting node TX (e.g., gNB) can transmit an eDRTS 702 on a beam (e.g., in direction “x”). This can be done, for example, after successfully performing CCA on the corresponding Rx beam. After successfully receiving the eDRTS 702, for example, a receiving node RX (e.g., UE) can transmit an eDCTS 704 on multiple beams. The beams can include Tx beams corresponding to the Rx beam on which the eDRTS 702 was received. The transmitting node can include a DL / UL switching configuration in the eDRTS 702. This configuration can be designed, for example, to allow reverse traffic 706 (e.g., from the receiving node to the transmitting node) to be repeated within a minimum LBT duration. 7, reverse traffic 706 can be transmitted on different adjacent beams, including, for example, the main / center beam on which the eDRTS / data / control was received, e.g., using multi-beam transmission 708. For example, in some embodiments, reverse traffic 706 can be transmitted on multiple beams, which can include the main / center Tx beam corresponding to the Rx beam on which the eDRTS 702 was received, and / or adjacent beams around the main Tx beam. This can prevent devices (e.g., all devices) located near the transmitting node from initiating / receiving a transmission (e.g., any transmission).

[0161] FIG. 8 is a flowchart illustrating an example of a transmission procedure according to some embodiments. The example of FIG. 8 can be applied, for example, when a transmitter, such as a gNB, has data to transmit to a receiver, such as a UE. In step 800, a Tx and Rx beam pair is configured and resource allocation is performed. In step 802, the transmitter performs CCA on the allocated resource opportunity. In step 804, the transmitter determines whether the channel is clear based on the CCA. If the channel is clear, the procedure proceeds to step 806, where the transmitter transmits an eDRTS and waits for a response from the receiver. If the channel is not clear, in step 808, the transmitter determines to use the next resource opportunity including another beam direction. In step 810, the transmitter determines whether an eDCTS has been received. If an eDCTS has been received, in step 812, the transmitter transmits (e.g., data) on the allocated frequency and time resources. If an eDCTS has not been received, the procedure returns to step 808. Next, in step 814, the transmitter determines whether data or control signals have been received from the receiver within the minimum LBT duration. If so, the procedure returns to step 812; if not, the procedure returns to step 808. If there is no more data to send, the procedure may end.

[0162] In some embodiments, there may be different UE behaviors that may be based on eDRTS transmission / reception and / or eDCTS transmission / reception. One or more of the following may apply: A UE that transmitted an eDRTS waits for an eDCTS from the receiving node. For example, if it receives an eDCTS within a predefined time interval, it may start its data transmission to the receiving node (e.g., gNB). This may follow the received DL / UL switching configuration. For example, if it does not receive an eDCTS from the receiving node within a predefined time interval, it may find the channel busy and / or decide to use another resource opportunity (e.g., including another beam direction) to perform CCA. A UE that received an eDRTS that includes information about its ID and / or an eCTS flag set to "1" may transmit an eDCTS to the transmitter of the eDRTS. A UE that received an eDRTS that includes information about its ID and / or an eCTS flag set to "0" may create a configuration to receive downlink data / control signals on the resources assigned in the eDRTS. A UE may not be able to transmit (e.g., any) eDRTS and / or may not receive an eDRTS / eDCTS that includes its UE ID. For example, if a UE receives an eDRTS and / or eDCTS that does not have its UE ID, it may back off and / or may not attempt to access the channel. This may be for a duration that may be included in the eDRTS / eDCTS.

[0163] According to some embodiments, a dynamic DL / UL switching configuration per beam pair link (BPL) using periodic eDCTS-to-self transmissions is further disclosed herein. In some exemplary embodiments, according to the disclosed configuration, other devices that may cause interference can be prevented from transmitting due to the periodic eDCTS-to-self transmissions. Furthermore, according to some embodiments, signaling and channel details for implementing the proposed control messages (e.g., eDRTS, eDCTS, and eDCTS-to-self) are disclosed herein for both downlink and uplink data transmissions.

[0164] In some embodiments, during data transmission, the transmitter or receiver, or both, may also transmit eDCTS-to-self to keep the directional channel reserved and to prevent (or at least mitigate) directional interference from neighboring devices. After receiving the eDCTS-to-self transmission, other devices may determine that the channel may be occupied and cannot initiate transmissions that may interfere with the transmissions protected by the eDCTS-to-self transmission.

[0165] In some embodiments, multiple eDCTS-to-self transmissions can be performed. The multiple transmissions can use antenna configurations or beams that can take advantage of one or more of the following characteristics, by way of example: (i) the eDCTS-to-self transmissions can use the same antenna configurations or beams as those for the initial eDRTS transmission, (ii) the eDCTS-to-self transmissions are performed using antenna configurations or beams that were not used for the initial eDRTS transmission, and / or (iii) some eDCTS-to-self transmissions can use the antenna configurations or beams that were used for the initial eDRTS transmission, while other eDCTS-to-self transmissions use antenna configurations or beams that are different from those used for the initial eDRTS transmission.

[0166] In some embodiments, the eDCTS-to-self configuration, including the eDCTS-to-self count, i.e., the number of eDCTS-to-self transmissions and the direction for the eDCTS-to-self transmissions, can be conveyed from the gNB to the UE in an eDRTS message in the case of a downlink transmission, or in an eDCTS message in the case of an uplink transmission.

[0167] In some embodiments, a UE or gNB can learn the number of eDCTS-to-self transmissions and the direction for the eDCTS-to-self transmissions through measurements. For example, the UE or gNB can determine the absence or presence of an interfering link through measurements, and eDCTS-to-self transmissions can occur only in directions or antenna configurations or beams known to be prone to interference. By way of illustration, for example, if the UE determines, based on the UE's measurements, interference that can potentially interfere with transmissions from the gNB in ​​the direction of a beam (data beam) on which the gNB transmits, e.g., data (or in the direction of a beam adjacent to the data beam), the UE can decide to transmit a control message (eDCTS, eDCTS-to-self) using the data beam and / or the adjacent beam to stop any interferers. In this regard, a node (e.g., UE) can be configured accordingly (e.g., using appropriate hardware / software) to map information regarding the interference direction and configure its beam direction accordingly for the transmission of such control messages.

[0168] Alternatively, in some embodiments, a grant request for eDCTS-to-self transmission can be included in an eDRTS / eDCTS message from the UE. If the UE sent the grant request in an eDRTS message, the UE can receive a grant for eDCTS-to-self from the gNB (or, in general, from a base station (BS)) in an eDCTS message. If the UE sent the grant request in an eDCTS message, the UE can receive a grant for eDCTS-to-self from the gNB (or, in general, from a BS), followed by an eDCTS transmission from the UE.

[0169] According to some embodiments, a grant request for eDCTS to self may include the following information, as shown by way of example in Table 5:

[0170] [Table 5]

[0171] In some embodiments, multiple consecutive eDCTS-to-self transmissions by a requesting node can have the same content. Under this embodiment, the Defer duration field can contain the actual DL data transmission duration. In another embodiment, the requesting node can modify the content of multiple consecutive eDCTS-to-self transmissions. For example, the transmitting node can modify the content of the Defer duration field in consecutive eDCTS-to-self transmissions.

[0172] It should be noted that one or more of the eDCTS-to-self transmissions may occur simultaneously, e.g., coincide in time with one or more eDCTS transmissions by the target UE.

[0173] FIG. 31 illustrates an example 2650 of downlink data transmission with eDCTS-to-self transmission, according to some embodiments. In the example of FIG. 31, the gNB transmits an eDRTS message 2652 to the UE. As shown, after successfully decoding the eDRTS message 2652, the UE transmits an eDCTS message 2654 to the gNB. Subsequently, the UE also transmits an eDCTS-to-self message 2656 using a different antenna configuration or beam to preserve the directional channel. In some embodiments, the direction for the eDCTS-to-self transmission can be configured by the gNB or determined by prior directional channel measurements. Furthermore, in some embodiments, the eDCTS-to-self transmission can be repeated once every T (or every given time period) (e.g., based on a minimum CCA duration) for the entire duration (e.g., MCOT) of the transmission / communication exchange between the gNB and the UE.

[0174] FIG. 32 illustrates another example 2670 of downlink data transmission with both eDCTS-to-self and uplink transmissions, according to some embodiments. In another example, as shown in FIG. 32, a gNB can transmit multiple eDCTS-to-self messages 2676 using different antenna configurations or beams after a successful eDRTS 2672, eDCTS 2674 exchange with a target UE, but before transmitting data (e.g., transmitting DL data 2678) to the target UE. In one embodiment, the number of consecutive eDCTS-to-self transmissions can be configured by the network or determined by the gNB based on prior directional channel measurements. The number of consecutive eDCTS-to-self transmissions can be included in an eDRTS transmission to the target UE. In another embodiment, the UE can include a request for consecutive eDCTS-to-self transmissions by the gNB. This request can be included in an eDCTS transmitted in response to an eDRTS received from the gNB. The request may specify the number of consecutive eDRTS-to-self transmissions requested and at least one of the gNB antenna configuration or beam. In some embodiments, the consecutive eDCTS-to-self transmissions may be repeated once every T (or every given time period) (e.g., based on a minimum CCA duration) for the entire duration (e.g., MCOT) of the transmission / communication exchange between the gNB and the UE.

[0175] In some embodiments, eDRTS, eDCTS, and eDCTS-to-self transmissions may be performed using a downlink shared channel (eg, PDSCH).

[0176] In some embodiments, the gNB may transmit an eDRTS message to initiate a downlink transmission, or an eDCTS message in response to an eDRTS message received from one of the UEs with which it is associated, or an eDCTS-to-self transmission, which may be transmitted in various manners as described herein above.

[0177] The eDRTS, eDCTS, and eDCTS-to-self transmissions from the gNB can be transmitted on the downlink shared channel in several ways.

[0178] In some embodiments, the eDRTS / eDCTS from the gNB may be transmitted only to the target UE, for example. In the case of an eDRTS transmission, the target UE may be a downlink data receiving UE. In the case of an eDCTS transmission, the target UE may be the UE that transmitted the eDRTS. The eDRTS / eDCTS from the gNB may be transmitted using a Tx beam paired with the target UE. The UE may receive control channel transmissions on a common channel (e.g., PDCCH). The control information may include downlink control information (DCI), which includes a cyclic redundancy check (CRC) sequence scrambled using the UE's C-RNTI. The UE may be able to recover the DCI and verify it by unscrambling the CRC using the C-RNTI.

[0179] In the case of an eDCTS-to-self message from a gNB, the DCI may include a CRC sequence scrambled using a scrambling code specific to the ID of the destination UE or gNB / eNB for the eDCTS-to-self, e.g., C-RNTI, cell ID, etc.

[0180] In some embodiments, the DCI may include a new flag to indicate the transmission as an eDRTS, eDCTS, or eDCTS-to-self message, which may help a receiving node distinguish an eDRTS / eDCTS / eDCTS-to-self message from other gNB transmissions that use the same RNTI to scramble the CRC sequence for the DCI.

[0181] In some embodiments, the control information may include a DCI including a CRC sequence scrambled using a scrambling code common to two or more UEs or two or more gNBs. In the case of an eDRTS transmission from a gNB, a common RNTI, e.g., RTS-RNTI, may be defined to decode the eDRTS message. In the case of an eDCTS transmission from a gNB, a common RNTI, e.g., CTS-RNTI, may be defined to decode the eDCTS message. In the case of an eDCTS-to-self transmission from a gNB, a common RNTI, e.g., self-CTS-RNTI, may be defined to decode the eDCTS-to-self message. The receiving node may be able to recover the DCI and verify it by unscrambling the CRC using the corresponding RNTIs, e.g., RTS-RNTI, CTS-RNTI, and self-CTS-RNTI.

[0182] In some embodiments, the UE and / or gNB may be pre-configured to use the RTS-RNTI, CTS-RNTI, and self-CTS-RNTI, e.g., via system information or UE-specific signaling. The RTS-RNTI, CTS-RNTI, and self-CTS-RNTI may be common network-wide. Alternatively, in some other embodiments, the RTS-RNTI, CTS-RNTI, and self-CTS-RNTI may be common to a group of eNBs / gNBs and used locally. In some embodiments, the UE may perform a blind search using its C-RNTI in a UE-specific search space in the PDCCH and one or more of the RTS-RNTI, CTS-RNTI, and self-CTS-RNTI, if configured, in a common search space in the PDCCH.

[0183] In some embodiments, in the case of eDRTS transmission, a new DCI format can be used to carry control information for eDRTS transmission in DL and / or eDCTS transmission in UL. In some embodiments, by way of example, the DCI can include the following fields: eDRTS flag (if the CRC sequence of the DCI is scrambled using the C-RNTI), DL resource block allocation (for DL ​​eDRTS transmission), MCS (for DL), UL resource block allocation (for UL eDCTS transmission by the UE), MCS (for UL), TPC for PUSCH, and / or resource block allocation (for data transmission after eDRTS and eDCTS transmission).

[0184] However, it will be understood that in other embodiments, the DCI may be configured differently (e.g., the DCI may include one or more different fields, additional fields, and / or fewer fields than disclosed herein).

[0185] According to some embodiments, in addition to the eDRTS message content given in Table 1, the eDRTS message may also include the following subset of information, as shown by way of example in Table 6:

[0186] [Table 6]

[0187] In some embodiments, in the case of eDCTS transmission from a gNB, a new DCI format can be used to include control information for eDCTS transmission in DL and / or data transmission in UL. In some embodiments, by way of example, the DCI can include the following fields: eDCTS flag (if the CRC sequence of the DCI is scrambled using the C-RNTI), resource block allocation (for DL ​​eDCTS transmission), MCS (for DL), resource block allocation (for UL data transmission by the UE), MCS (for UL), and / or TPC for PUSCH.

[0188] However, it will be understood that in other embodiments, the DCI may be configured differently (e.g., the DCI may include one or more different fields, additional fields, and / or fewer fields than disclosed herein).

[0189] According to some embodiments, in addition to the eDCTS message contents given in Table 2, the eDCTS message may also include the following subset of information, as shown by way of example in Table 7:

[0190] [Table 7]

[0191] In some embodiments, in the case of eDCTS-to-self from a gNB, the DCI may include a resource block allocation for the eDCTS-to-self message and a flag, i.e., an eDCTS-to-self flag, if the CRC sequence of the DCI for the eDCTS-to-self message is scrambled using the C-RNTI.

[0192] According to some embodiments, in addition to the eDCTS-to-self message contents given in Table 4, the eDCTS-to-self message may also include the following subset of information, as shown by way of example in Table 8:

[0193] [Table 8]

[0194] In some embodiments, a UE may be able to receive more than one eDRTS / eDCTS transmission from a requesting gNB (in the case of an eDRTS transmission) or a responding gNB (in the case of an eDCTS transmission). This may occur when the requesting gNB (in the case of an eDRTS transmission) or the responding gNB (in the case of an eDCTS transmission) may repeat an eDRTS / eDCTS transmission using a different antenna configuration, e.g., a different beam. In one embodiment, the message content in the repeated eDRTS / eDCTS transmissions may be identical. The eDRTS / eDCTS message may include a start time field and a transmission duration field to indicate the actual DL data transmission schedule.

[0195] In some other embodiments, the content of multiple eDRTS / eDCTS transmissions can differ from one another. For example, in some embodiments, the transmission duration field in each successive transmission of an eDRTS / eDCTS message can be decreased by the amount required for a single eDRTS / eDCTS message transmission. In one embodiment, after successfully receiving one eDRTS / eDCTS transmission in the current allocation, the recipient (or destination) UE can stop the reception process.

[0196] In some embodiments, the content of the eDRTS / eDCTS / eDCTS-to-self message can be scrambled using a sequence common to a group of cells, e.g., a cell group sequence (CGS). In one embodiment, a common CGS can be used for the entire operator network. In another embodiment, a single CGS can be frequency channel or subband specific (e.g., all devices operating in a specified frequency channel or subband can support the same CGS).

[0197] In yet another embodiment, the UE can be configured to use multiple CGSs. The UE can perform blind decoding on any eDRTS / eDCTS / eDCTS-to-self transmission using each of the configured CGSs to read the message content. Alternatively, in some embodiments, a DCI can be associated with an eDRTS / eDCTS / eDCTS-to-self message and contain information, e.g., a configuration, about the CGS that will be used to scramble the subsequent eDRTS / eDCTS / eDCTS-to-self message.

[0198] In some embodiments, in the case of an eDRTS transmission from a gNB, a UE attached to a different cell can configure its receive antenna pattern, e.g., beam pattern, for subsequent eDCTS reception based on the CGS that resulted in successful descrambling of the eDRTS message.

[0199] In some embodiments, the UE may be configured to use CGS, for example, via system information or higher layer control messaging, for example, RRC messages.

[0200] In some embodiments, in cases where the eDRTS / eDCTS message can be sent only to the target UE, the eDRTS / eDCTS message can be scrambled using a sequence generated using the cell ID and a UE-specific RNTI, e.g., C-RNTI. The contents of the eDCTS-to-self message can be scrambled using a sequence generated using the target receiver ID, e.g., C-RNTI, and the cell ID.

[0201] Note that in the content of the eDCTS message, the receiver ID (field) can be the same as the UE's C-RNTI, for example, as shown in Table 2. Alternatively, the receiver ID can be a different ID, configured using, for example, control channel signals, higher layer signaling, etc.

[0202] In some embodiments, eDRTS, eDCTS, and eDCTS-to-self transmissions may be performed using an uplink shared channel (eg, PUSCH).

[0203] In some embodiments, the UE may transmit an eDRTS message to request an uplink transmission, or an eDCTS message in response to an eDRTS message received from a BS (base station) associated with the UE, or an eDCTS-to-self transmission, which may be transmitted in various manners as described above in this specification.

[0204] The eDRTS, eDCTS, and eDCTS-to-self transmissions from the UE can be transmitted on the uplink shared channel in several ways.

[0205] In some embodiments, the UE may receive control channel transmissions on a common channel (e.g., a PDCCH). The received control information may include DCI, including grants for uplink transmissions on a shared channel, e.g., a Physical Uplink Shared Channel (PUSCH).

[0206] In some embodiments, the DCI may include an allocation by the UE to an associated BS, e.g., eNB / gNB, for a single eDRTS / eDCTS / eDCTS-to-self transmission. The eDRTS / eDCTS may be transmitted using a Tx (transmit) beam paired with the associated BS.

[0207] In another embodiment, the DCI may include an allocation for multiple, e.g., two or more, eDRTS / eDCTS / eDCTS-to-self transmissions by the UE. In some embodiments, the UE can still determine the number of DRTS / eDCTS / eDCTS-to-self transmissions. For example, the UE can transmit a single eDRTS / eDCTS / eDCTS-to-self message in an allocation that can accommodate multiple, e.g., two or more, eDRTS / eDCTS / eDCTS-to-self transmissions.

[0208] In some embodiments, the eDRTS / eDCTS message may include a field to indicate the number of eDRTS / eDCTS transmissions. In one embodiment, the number indicated in the field may be the total number of eDRTS / eDCTS transmissions in the current sequence. In another embodiment, the number may be the remaining number of eDRTS / eDCTS transmissions in the current sequence.

[0209] In some embodiments, the UE may transmit the eDRTS / eDCTS to the associated BS first in a sequence of multiple eDRTS / eDCTS transmissions. In other embodiments, the UE may transmit the eDRTS / eDCTS to the associated BS last in a sequence of multiple eDRTS / eDCTS transmissions. In one embodiment, the UE may not include a field to indicate the total number of eDRTS / eDCTS transmissions in the current sequence. In yet another embodiment, the UE may transmit the eDRTS / eDCTS to the associated BS at a random location in the current sequence of multiple eDRTS / eDCTS transmissions.

[0210] In some embodiments, the UE can determine whether the channel is free for transmission for a specified duration prior to the scheduled start of an eDRTS / eDCTS transmission. In some embodiments, the monitoring duration can be pre-configured in the UE or known to the UE. For example, the UE can perform CCA (e.g., LBT) during the monitoring duration. The determination (e.g., CCA) can be made prior to the time when transmission can begin.

[0211] In some embodiments, in the case of eDCTS transmission, when the UE correctly receives the DL eDRTS message during the monitoring duration and determines that the channel may be available, the UE can transmit (e.g., begin transmitting) the eDCTS message on the assigned resources. When the UE correctly receives the DL eDRTS message and determines, e.g., based on CCA, that the channel may be busy, the UE cannot transmit the eDCTS message on the assigned resources. The UE can, e.g., delay transmission until a later time.

[0212] In some embodiments, in the case of eDRTS transmission, when the UE determines that the channel may be available during the monitoring duration, the UE may transmit (e.g., begin transmitting) the eDRTS message on the assigned resources. When the UE determines, e.g., based on CCA, that the channel may be busy, the UE may not transmit the eDRTS message on the assigned resources. The UE may, for example, delay the transmission until a later time. In general, the transmission may be conditional on whether the transmission fits within the remaining time resources of the scheduled allocation.

[0213] In some embodiments, a UE may be configured to transmit multiple eDRTS / eDCTS messages, with successive eDRTS / eDCTS transmissions using different antenna configurations, e.g., different beams.

[0214] In one embodiment, multiple eDRTS / eDCTS transmissions from a UE may have identical content. The eDRTS / eDCTS message may include a start time field and a transmission duration field to indicate the actual data transmission schedule.

[0215] In other embodiments, the UE may modify the content of eDRTS / eDCTS messages transmitted using different antenna configurations, e.g., different beams. In one embodiment, the UE may decrease the transmission duration field in each successive transmission of an eDRTS / eDCTS message by the amount required for a single eDRTS / eDCTS message transmission.

[0216] In some embodiments, the content of the eDRTS / eDCTS / eDCTS-to-self message can be scrambled using a sequence, e.g., a CGS, that is common to a group of cells. In one embodiment, a common CGS can be used for the entire operator network. In another embodiment, a single CGS can be frequency channel or subband specific (e.g., all devices operating in a frequency channel subband can support the same CGS).

[0217] In yet another embodiment, the UE may be configured to use multiple CGSs. The UE may use any of the configured CGSs, e.g., randomly. Alternatively, in some other embodiments, a DCI may be bound to the eDRTS / eDCTS / eDCTS-to-self message and may contain information, e.g., a configuration, about the CGS to be used to scramble the subsequent eDRTS / eDCTS / eDCTS message. In some embodiments, the UE may use the DCI in, e.g., system information or higher layer control messaging, e.g., RRC messages. In some embodiments, eDRTS, eDCTS, and eDCTS-to-self transmissions may be performed using an uplink common channel.

[0218] In some embodiments, the UE may not have previously received any specific UL resource grant for the purpose of eDRTS / eDCTS / eDCTS-to-self transmission from an associated BS, e.g., eNB / gNB, associated with the UE. If the UE determines that resources are not granted for eDRTS / eDCTS / eDCTS-to-self transmission, in some embodiments, the UE may transmit the eDCTS message using UL grant-free resources.

[0219] In some embodiments, the UL grant-free channel may be designed in one or more of the following ways, for example, as described below.

[0220] The UL grant-free channel may be located in one or more subframes within each frame, or within a frame, e.g., a frame with a certain SFN number or a frame with a certain characteristic. The subframe and / or frame and / or frame characteristics may be fixed or may be a function of the physical ID of the cell (cell ID).

[0221] The UE may be pre-configured to use the location of the UL grant-less channel, e.g., via system information, downlink broadcast information, or UE-specific signaling. The sequence and / or identifier used for scrambling the UL grant-less channel may be common to a group of cells, e.g., a CGS. In one embodiment, a common CGS may be used for the entire operator network. In another embodiment, a single CGS may be frequency channel or subband specific (e.g., all devices operating in a frequency channel or subband support the same CGS). In yet another embodiment, the UE may be configured to use multiple CGSs.

[0222] A UE may be configured to use multiple CGSs, for example, via system information or higher layer control messaging, eg, RRC messages.

[0223] The gNB and / or UE may be configured to listen to and decode the UL grant-free channel.

[0224] Demodulation Reference Signal (DM-RS)-based transmission can be used. The sequence for deriving the DM-RS can be based on a common sequence, e.g., a CGS. In one embodiment, the sequence for deriving the DM-RS can be based on a UE-specific sequence. The location of the DM-RS in the dedicated resources can be fixed, known, or configured.

[0225] In some embodiments, the UE may wait for a duration from the start of the UL grant-free resource. The waiting time may be, for example, randomly determined. After waiting, the UE may first determine whether the channel may be clear for transmission for a specified duration prior to any transmission. The monitoring duration may be pre-configured in the UE or may be known to the UE. For example, the UE may perform CCA (e.g., LBT) during the monitoring duration. The determination (e.g., CCA) may be made before the time when transmission may begin. After successful CCA, the UE transmits eDRTS / eDCTS / eDCTS-to-self on the UL grant-free resource.

[0226] In some embodiments, in the case of eDCTS-to-self transmission, the UE can inform the BS by conveying the number of eDCTS-to-self messages in the eDRTS message (in the case of uplink) or in the eDCTS message (in the case of downlink transmission). In some embodiments, this information can be transmitted along with the ID of the beam, e.g., the beam intended to be used during the eDCTS-to-self transmission.

[0227] In some embodiments, the eDRTS transmission may be performed using dedicated resources on an uplink control channel (eg, PUCCH).

[0228] In some embodiments, a UE can be allocated dedicated resources on the PUCCH for transmitting eDRTS in various ways. The dedicated resources can be located in each frame or in one or more subframes within a frame, e.g., a frame with a certain SFN number or a frame with a certain characteristic. The subframe and / or frame and / or frame characteristics can be fixed or can be a function of the physical ID (cell ID) of the cell. The dedicated resources can be allocated within a set of symbols, a short TTI, a minislot, etc. The dedicated resources can be allocated within a set of one or more subcarriers. Demodulation Reference Signal (DM-RS)-based transmission can also be used. In this regard, the location of the DM-RS in the dedicated resources can be fixed, known, or configured.

[0229] In some embodiments, the eDRTS on the dedicated resources may be scrambled using a UE-specific scrambling sequence.

[0230] The UE may be pre-configured to use dedicated resource allocation and may further be configured to use a UE-specific scrambling sequence, for example, via higher layer signaling messages, e.g., RRC connection setup or via system information.

[0231] In some embodiments, when a UE needs to transmit an eDRTS, it first performs CCA prior to the next available dedicated resource opportunity. After successful CCA, the UE transmits the eDRTS on the dedicated resource.

[0232] Some embodiments disclose the behavior of non-targeted UEs and neighboring gNBs / eNBs upon receiving an eDRTS / eDCTS / eDCTS-to-self.

[0233] That is, in some embodiments, a non-targeted UE or neighboring BS that receives an eDRTS or / and eDCTS or / and eDCTS-to-self transmission that includes another cell's ID or another UE's ID (e.g., C-RNTI) cannot transmit on the channel for the transmission duration indicated in the message. The transmission duration can be specified for the entire message exchange, including the remaining eDRTS, eDCTS, eDCTS-to-self transmissions and subsequent data transmissions. Alternatively, the transmission duration can be specified in terms of start time and duration.

[0234] In other embodiments, a UE belonging to a neighboring cell or a neighboring BS that receives an eDRTS or / and eDCTS or / and eDCTS-to-self transmission that includes another cell ID or UE ID (e.g., C-RNTI) may transmit on a frequency channel or subband if it determines that doing so will not cause interference to subsequent transmissions associated with the received eDRTS / eDCTS / eDCTS-to-self message.

[0235] In some embodiments, a receiving non-targeted UE or neighboring BS can determine that its directional transmissions may not cause interference to a proposed directional data transmission between an eDRTS / eDCTS / eDCTS-to-self transmitter and a corresponding receiver. In some embodiments, such a determination can be made by first determining the direction of the proposed data transmission. In another embodiment, the direction of the proposed transmission can be determined from the Targeted Receiver ID and Requested Transmitter ID fields included in the eDRTS / eDCTS / eDCTS-to-self message. This may be possible when the receiving non-targeted UE or neighboring BS knows the location and orientation of the transmitter and receiver. In another embodiment, if possible, this determination can be based on the contents of the Requested Transmitter ID and Tx Beam ID fields of the eDRTS / eDCTS / eDCTS-to-self message.

[0236] Assuming that a non-targeted UE belonging to a neighboring cell, or a neighboring BS, can determine, after exchanging eDRTS, eDCTS, and eDCTS-to-self (if any), whether its directional transmission (e.g., UL or DL ​​transmission) can not interfere with the directional transmission between the BS and the target UE, then that UE or neighboring BS can perform parallel (e.g., simultaneous) directional transmissions.

[0237] After the completion of a transmission duration, in some embodiments, the UE or BS can first determine whether the channel is clear for transmission for a specified duration prior to any subsequent transmission. The monitoring duration can be configured in advance or can be known to the UE or BS. For example, the UE can perform CCA (e.g., LBT) during the monitoring duration. The determination (e.g., CCA) can be made before the time when transmission can begin.

[0238] 33 illustrates an example 2700 of eDRTS, eDCTS, and eDCTS-to-self transmissions according to some embodiments. In this example, the eDRTS transmissions may be transmitted using a downlink shared channel, such as a PDSCH, and the eDCTS transmissions may be transmitted using allocated resources on an uplink shared channel. Furthermore, the downlink transmissions use eDCTS-to-self transmissions to protect the current transmission.

[0239] As shown in FIG. 33, at 2701, a transmitting node, such as the gNB of FIG. 33, can first perform CCA to determine whether the channel is clear / vacant for transmission. Once the gNB determines that the channel is clear, at 2702, it can transmit a new DCI on a downlink common channel, such as a PDCCH, to the receiving node, which is the target UE in FIG. 33. The DCI can be scrambled using a common RNTI. The common RNTI can be common to two or more UEs or common across the entire network, such as an SI-RNTI. Furthermore, the DCI can include DL and UP resource allocations for eDRTS and eDCTS transmissions, respectively. At 2704, the gNB can transmit multiple eDRTSs, including at least one eDRTS transmitted in the direction of the target UE and at least one eDRTS transmitted in the direction of non-target UEs and / or neighboring gNBs, as shown in FIG. 33. For example, if configured, the gNB may perform repeated eDRTS transmissions 2706 in multiple directions, as shown in Figure 33. The gNB may perform eDRTS transmissions 2706 in multiple directions to, for example, reserve a channel in a larger area around the receiving node, i.e., the target UE.

[0240] In some embodiments, each transmitted eDRTS may include a target UE ID, a requester (gNB) ID, a transmission duration (Tx duration), a start time, a Tx (transmit) beam ID, etc. Additionally, the eDRTS may be scrambled using a CGS, which may be common to a group of cells, for example.

[0241] When the target UE receives the eDRTS from the gNB, the target UE may decode the eDRTS and determine that the UE ID included in the eDRTS corresponds to the target UE's ID at 2708. Similarly, when a non-target UE and / or a neighboring gNB receives the eDRTS from the gNB, the non-target UE and / or the neighboring gNB may decode the eDRTS and determine that the UE ID included in the eDRTS does not match the target UE's ID at 2710. Furthermore, the non-target UE and / or the neighboring gNB may obtain a transmission duration (or at least an indication thereof) from the decoded eDRTS. Thus, as time period 2712 indicates, the non-target UE and / or the neighboring gNB may not initiate transmission during the Tx duration obtained from the received eDRTS. As a result, the non-target UE and / or the neighboring gNB may be prevented from interfering with transmissions between the gNB and the target UE during at least that time period.

[0242] At 2714, the target UE may perform CCA to check whether the channel is clear. If the target UE determines that the channel is clear, at 2716, the target UE may transmit one or more eDCTSs toward the gNB. For example, as shown in FIG. 33, the target UE, if so configured, may perform multiple repeated eDCTS transmissions 2718 in multiple directions. The eDCTSs 2718 may be transmitted on allocated resources using an uplink shared channel, such as a PUSCH, and each eDCTS may be scrambled using a CGS. Following receipt of the eDCTS transmission from the target UE, the gNB may initiate a downlink (DL) data transmission at 2720. The DL data transmission may be followed by one or more eDCTS-to-self transmissions during a period T (indicated by 2724 in FIG. 33), which may correspond, for example, to a minimum LBT duration. For example, as shown in Figure 33, a gNB may perform multiple repeat eDCTS-to-self transmissions 2722 in multiple directions, if so configured, during a period 2724. The eDCTS-to-self transmissions may be performed to keep the (directional) channel between the gNB and the target UE secured from access by potential interfering nodes.

[0243] If the gNB has additional data to transmit, it transmits the additional DL data to the target UE at 2726. The DL data transmission may again be followed by one or more eDCTS-to-self transmissions from the gNB, as shown in Figure 33. For example, as shown in Figure 33, the gNB may perform multiple repeat eDCTS-to-self transmissions 2722 in multiple directions (if so configured).

[0244] 34 illustrates an example of behavior at a non-targeted UE 2800 after receiving an eDRTS and eDCTS from another cell, according to some embodiments. In this example, as shown in FIG. 34, after receiving the eDRTS and eDCTS from another cell, the non-targeted UE determines a non-interfering transmission direction and begins uplink transmission by transmitting an eDRTS to a BS associated with the UE using an uplink common channel.

[0245] More specifically, as shown in FIG. 34, in 2801, a transmitting node, such as gNB1 in FIG. 34, can transmit multiple eDRTSs on a downlink shared channel, such as a PDSCH, including at least one eDRTS transmitted in the direction of a target UE associated with a receiving node, e.g., gNB1, and at least one eDRTS transmitted in the direction of a non-target UE associated with, e.g., a neighboring gNB (gNB2), as shown in FIG. 34. For example, if configured, gNB1 can perform repeated eDRTS transmissions 2802 in multiple directions as shown in FIG. 34. In some embodiments, each transmitted eDRTS is scrambled using a CGS and can include a target UE ID, a requester (gNB1) ID, a transmission duration (Tx duration), a start time, a Tx (transmit) beam ID, etc. The CGS can be common to a group of cells. When the target UE receives the eDRTS from the gNB1, the target UE may decode the eDRTS and determine that the UE ID included in the eDRTS corresponds to the ID of the target UE, at 2804. Similarly, when the non-target UE receives the eDRTS from the gNB, the non-target UE may decode the eDRTS and determine that the UE ID included in the eDRTS does not match the ID of the non-target UE, at 2806.

[0246] As further shown in FIG. 34, the target UE may transmit one or more eDCTSs at 2808. For example, as shown in FIG. 34, the target UE, if configured to do so, may perform multiple repeated eDCTS transmissions 2810 in multiple directions. The eDCTSs may be transmitted on earlier allocated resources (e.g., resources allocated by gNB1) using an uplink shared channel such as a PUSCH, and each eDCTS may be scrambled using a CGS. As FIG. 34 illustrates, the multiple repeated eDCTS transmissions 2810 may include at least one eDCTS transmission in the direction of the non-target UE. Thus, the non-target UE may receive one or both of the eDRTS and the eDCTS. If the non-target UE receives the eDCTS, it may decode the eDCTS at 2812. At 2814, the non-target UE may determine a non-interfering transmission direction or a direction of transmission that would not interfere with transmissions between gNB1 and the target UE. In some embodiments, for example, the non-targeted UE can determine the non-interfering transmission direction based on knowledge of the respective locations and orientations of the transmitter and receiver (e.g., gNB1 and the target UE, as in the case of FIG. 34). In this regard, the respective locations and orientations of the transmitter / receiver can be used, for example, to identify beams that the non-targeted UE can use for transmissions that do not interfere with reception at the target UE. In other embodiments, the non-targeted UE can have historical measurements from which the non-targeted UE can extract information regarding the non-interfering transmission direction.

[0247] Following the determination of the non-interfering transmission direction, the non-targeted UE may perform one or more eDRTS transmissions directed toward the gNB2 associated with the UE at 2816. For example, as shown in FIG. 34, the non-targeted UE, if so configured, may perform multiple repeated eDRTS transmissions 2818 in multiple directions. Each eDRTS transmitted by the non-targeted UE may be scrambled using an associated CGS and transmitted on a common or grant-less uplink channel. Following the eDRTS transmission from the non-targeted UE, the gNB2 may transmit a new DCI to the non-targeted UE at 2820 on a downlink common channel, such as a PDCCH. The DCI may include resource allocation information for the eDCTS. The DCI may be scrambled using a common RNTI. The common RNTI may be common to two or more UEs or common across the entire network, e.g., SI-RNTI. As indicated in the DCI transmission, gNB2 may transmit one or more eDCTSs to non-target UEs on a downlink shared channel (e.g., PDSCH) at 2822. For example, if configured, gNB2 may perform repeated eDCTS transmissions 2824 in multiple directions, as shown in Figure 34. Each of the eDCTSs may be scrambled using a CGS and transmitted by gNB2 on a downlink shared channel, such as a PDSCH.

[0248] According to some embodiments, implementations related to coexistence of directional NR-WiGig systems in unlicensed spectrum can also be provided.

[0249] A WiGig device can use a detection threshold (e.g., a higher detection threshold) for non-WiGig system transmissions, which may not have a (e.g., special) preamble when processing CCA. For example, if it senses higher interference from non-WiGig devices than it senses from WiGig devices, the WiGig device can back off. NR transmissions can use short periodic transmissions (e.g., minislot durations) in the reverse direction (e.g., opposite the intended communication direction). This can cause WiGig devices to back off.

[0250] For example, when there is NR-WiGig coexistence, an NR device (e.g., a gNB and / or UE) can use (e.g., same) channel CCA and / or (e.g., same) channel reservation procedures as described for the NR-NR coexistence scenario, with one or more of the following modifications applied: The NR device can use (e.g., a single) block transmission from the receiving node for (e.g., each) minimum contention window. The NR device can use multiple block transmissions from the receiving node for (e.g., each) minimum contention window. The NR device can use increased power block transmissions from the receiving node for (e.g., each) minimum contention window.

[0251] In some embodiments, for example, with respect to using a (e.g., single) block transmission from a receiving node for (e.g., each) minimum contention window, one or more of the following may apply:

[0252] The DL / UL switching configuration for NR transmissions can be determined based on the (e.g., minimum) distributed inter-frame spacing (DIFS) period of the WiGig system. FIG. 9 illustrates an exemplary DL / UL switching configuration 850 for an NR-WiGig coexistence scenario according to some embodiments. For example, as shown in FIG. 9, reverse transmissions from the UE to the gNB on the beam corresponding to the Rx beam on which the forward transmission from the gNB was received can be repeated within a minimum contention window (min CW) (e.g., following a successful LBT and a successfully decoded eDRTS 852 followed by an eDCTS 854, as shown in FIG. 9). The min CW can be set to the minimum distributed inter-frame spacing (DIFS) period of the WiGig system. As seen in FIG. 9, "D" can be defined as the smallest data or control block interval that can carry a meaningful data packet (e.g., a symbol and / or a minislot, etc.). The reverse direction can be defined as the direction from the receiving node to the transmitting node.

[0253] The exemplary DL / UL switching configuration 850 shown in Figure 9 can use, for example, a single reverse power control minislot transmission to back off a WiGig device. As shown in Figure 9, a power control burst transmission 856 in the reverse direction (e.g., a burst transmission below the maximum (max) allowed Tx power at the UE, as shown in Figure 9) may be able to back off the device. The device may be within a range that may be relatively short.

[0254] The example of FIG. 9 may be appropriate for non-interfering NR-WiGig coexistence, as illustrated by the example of FIG. 10. More specifically, FIG. 10 illustrates example forward and / or reverse link beam coverage for a non-interfering scenario with NR-WiGig coexistence, according to some embodiments. As seen in FIG. 10, the STA 900 and the gNB 902 may not interfere with each other. This may be due to directional transmissions (e.g., DL directional transmissions from the gNB 902 to the UE 906 may not interfere with the STA 900, and / or UL directional transmissions from the STA 900 to the AP 904 may not interfere with the gNB 902). The distance between the AP 904 and the UE 906 may be large. The coexistence scenario shown in FIG. 10 may be referred to as non-interfering because, for example, DL AP transmissions may create interference (e.g., limited interference) to the UE 906. This interference may be negligible. This interference may be due to distance and / or propagation loss. UL UE transmissions may create interference to the AP 904, which may be due to distance (and / or corresponding propagation loss), which may be large. This interference may be limited and / or negligible.

[0255] In some embodiments, for example, with respect to using multiple block transmissions from a receiving node for (e.g., each) minimum contention window, one or more of the following may apply:

[0256] The receiving node can transmit multiple blocks ("D" size blocks) in the direction of the transmitting node. This may, for example, increase the interference range (and thus increase the likelihood of causing a potentially interfering WiGig AP node to back off, e.g., as shown in FIG. 12). FIG. 12 illustrates example forward and / or reverse link beam coverage for an AP-to-UE interference scenario in NR-WiGig coexistence, according to some embodiments. In the example of FIG. 12, reverse transmissions may not be able to back off the WiGig AP 1000. Multiple "D" block transmissions in the reverse direction (e.g., in the direction of the transmitting node) are shown in FIG. 11. More specifically, FIG. 11 illustrates another example DL / UL switching configuration 950 for an NR-WiGig coexistence scenario, according to some embodiments.

[0257] 11, there may be a limit that can be defined on the reverse link that indicates the number (M) of D blocks 952 used at a given power (e.g., the allowed number of D blocks). The value of M can be determined based on QoS and / or mapped to a finite integer. The same DL / UL switching configuration method can be applied, for example, for all types of QoS and / or mapping. Transmission of multiple blocks 952 in the reverse direction can also be used in NR-NR coexistence scenarios.

[0258] The exemplary configuration shown in Figure 11 can use multiple reverse minislot transmissions, for example, to backoff a WiGig device. This can be used, for example, for the interference scenario illustrated in Figure 12. As can be seen in Figure 12, the AP 1000 can interfere (e.g., significantly interfere) with the UE 1002. This can be due to the smaller distance between the AP 1000 and the UE 1002. As can be seen in Figure 12, the interference from the AP to the UE is highlighted as a dashed line.

[0259] In some embodiments, for example, with respect to using power-increased block transmissions from a receiving node for a minimum contention window, such as each minimum contention window, one or more of the following may apply:

[0260] The reverse link (e.g., receiving node transmissions in the direction of the transmitting node) may use higher power. This may occur, for example, to increase the likelihood of causing backoff of interfering transmissions. This can be seen in FIG. 13 and / or can be used for interference scenarios such as those illustrated in FIG. 14. That is, FIG. 13 illustrates an example DL / UL switching configuration 1050 for an NR-WiGig coexistence scenario using higher power and multiple reverse minislot transmissions to backoff WiGig devices, according to some embodiments. FIG. 14 illustrates example forward and / or reverse link beam coverage for an interference scenario in NR-WiGig coexistence, according to some embodiments. In the example of FIG. 14, AP DL transmissions may cause interference to the UE 1100 and / or UE UL transmissions may cause interference to the AP 1102. This may be due to the distance between the nodes.

[0261] For example, in FIG. 13, during the (e.g., initial) recursive process in which UL / DL link quality can be established, the reverse link can start (e.g., start only with) a single power control block (D-length) transmission toward the gNB, as shown in FIG. 9. The UE can determine the presence of an interferer, e.g., based on the measured SIR, and / or it can decide to transmit a (e.g., single) D block, e.g., at the maximum Tx power allowance. For example, if the UE still receives interference, it can increase the number of D blocks 1052 on the reverse link at the (e.g., maximum) allowable power. This can continue, e.g., until the UE utilizes M number of D blocks 1052 (M can be predetermined based on the effective forward link QoS mapping from the gNB to the UE and / or from the UE to the gNB). For example, if the UE still receives interference, it can still use the link with a (e.g., lower) MCS index selection that may be appropriate for the (e.g., measured) SIR.

[0262] In some embodiments, transmissions using higher power in the reverse direction may also be used for NR-NR coexistence scenarios, as described herein above.

[0263] 14, for example, a scheme for reverse transmission (e.g., transmission of UE 1100) discussed herein with respect to FIG. 13 may be able to backoff an interfering node and / or mitigate interference. For example, reverse transmission of UE 1100 may be able to backoff WiGig AP 1102.

[0264] As discussed, reverse transmissions using higher power can be transmitted on a beam wider than the Rx beam on which the forward transmission is received. The wider beam can be centered along the same beam direction as the Rx beam on which the forward transmission is received. Alternatively, the reverse transmissions can be transmitted on multiple adjacent beams around the Rx beam on which the forward transmission is received. For example, if the direction of an interferer is known by the receiver, the reverse transmissions can be transmitted only on beams pointing toward the interferer. The level of transmit power and the number of D blocks on any beam can be determined by the same procedure described above.

[0265] In some embodiments, a paired LBT related implementation can be provided.

[0266] Directional LBT assessment can be performed in the direction of the receiving node and / or in the opposite direction (as in legacy LBT or WiGig). For example, this can avoid the interference situations illustrated in FIGS. 3A and / or 3B or 4A and / or 4B. If a transmitting node performs LBT in a straight line toward the receiving node direction "dir," LBT can be performed in the (e.g., opposite) direction dir+X°. The direction can indicate a single direction (e.g., dir, dir+180°, supplementary direction) and / or a set of directions (e.g., dir+180°, dir+160°, dir+200°). This can depend on whether the LBT beams can be reconfigured and / or can be predefined (e.g., based on a set of previously configured beams). This is sometimes referred to as "paired LBT." Paired LBT can involve LBT on a "paired direction," which can indicate the direction toward the receiving node, the opposite direction, and / or the direction toward an expected interferer. In paired LBT, backoff and / or contention window status can be maintained per paired direction. This can reduce (e.g., by a factor of 2) the memory that may be used to track the backoff process per beam compared to, for example, per beam contention window.

[0267] In the examples shown in Figures 3A and 3B, the transmitting node may be a gNB and the receiving node may be a UE. If the gNB performs paired LBT (e.g., to evaluate channel availability), AP transmissions may be detected at the gNB and / or gNB transmissions may be postponed. This may avoid interference from the AP to the UE (as seen in Figures 3A and / or 3B) and / or interference from the gNB to the STA (as seen in Figure 3B).

[0268] In the examples shown in Figures 4A and 4B, the transmitting node may be a UE and the receiving node may be a gNB. When the UE performs paired LBT (e.g., to evaluate channel availability), the UE may detect a busy channel, which may be due to AP transmission, and / or the UE transmission may be postponed. This may avoid interference from the AP to the gNB (as seen in Figures 4A and 4B) and may avoid interference from the UE to the STA (as seen in Figure 4B).

[0269] Paired LBTs, facing and / or facing away from the receiving node, can occur (e.g., simultaneously). This can occur whenever (e.g., whenever) the transmitting node desires to transmit to the receiving node (e.g., by using multiple radio frequency (RF) chains and / or a single RF chain with advanced sampling techniques). The (e.g., every) LBT energy detection (ED) stage can sense the channel is idle for a known period of time (e.g., at least DIFS plus backoff time) and initiate data transmission.

[0270] Paired LBT can enable successful access to the medium under coexistence of (e.g., various) RATs with directional transmission and reception and / or can minimize the hidden node problem. Paired LBT can be used, for example, as a spectrum sharing technique within a (e.g., single) RAT (e.g., NR or WiGig) when, for example, coordination between nodes of the RATs may not be possible. For example, such coordination may not be possible if operators decide, for example, to use the same unlicensed spectrum and not have their respective networks coordinated.

[0271] For example, for paired LBTs as described herein, the transmit and receive directional antenna patterns can be described by one or more of the following parameters: Tx Gain G with Tx,m Main lobe and / or beam width 2π-θ Tx Gain G with Tx,s The receiving directional antenna pattern has a beamwidth θ Rx Gain G with Rx,m Main lobe and / or beam width 2π-θ Rx Gain G with Rx,s side lobes.

[0272] FIG. 15A illustrates an example of a single counter-directional paired LBT, according to some embodiments. FIG. 15B illustrates an example of multiple counter-directional paired LBT, according to some embodiments. Communication can occur between a transmitting node and / or a receiving node. FIGS. 15A and 15B illustrate DL communication (e.g., gNB 1200 can be the transmitting node and UE 1202 can be the receiving node). However, in other embodiments, communication can occur in the opposite direction (e.g., UL communication (UE to gNB)), for example, by switching the location of the gNB and the location of the UE.

[0273] 15A and 15B illustrate a situation where beam modeling is assumed. The transmitting node (gNB1200) has a receiving node direction “dir” and a beamwidth θ Tx LBT can be performed on a Tx beam direction (e.g., a beam that a transmitting node can use for data transmission toward a receiving node) that is straight toward the receiving node (LBT dir ) The transmitting node is in the opposite direction dir + 180° (as seen in Figure 15A) and has a main lobe beamwidth θ sup , and / or the main lobe gain G sup,mLBT in a single opposite direction with a beam that is straight towards dir+180° ), and / or multiple LBTs in multiple opposite directions (e.g., LBTs dir+180° , LBT dir+160° , LBT dir+210° ) can be performed (e.g., simultaneously). The multiple LBTs are each performed in opposite directions dir+X° (e.g., X=160°, 180°, 200°) (as shown in FIG. 15B), with a main lobe beamwidth θ sup , and / or the main lobe gain G sup,m The beam may be directed straight towards the target.

[0274] The beam used for LBT in the opposite direction is determined by the shape of the Tx beam 1204 of the transmitting node (e.g., θ 1 , as seen in Figures 15A and 15B). sup =θ Tx ), and / or have different patterns (as described in more detail below).

[0275] To illustrate hidden nodes, an Rx beam 1206 of a receiving node is illustrated in Figures 15A and 15B. AP 1208 can be a hidden node for legacy LBT, for example, if its transmission is within the boresight of the Rx antenna of the receiving node. For example, a paired LBT procedure as described herein can mitigate (e.g., some) hidden node problems (as seen in resolved hidden node region 1210 in Figures 15A and 15B). An AP (e.g., all APs) whose location may be within the resolved hidden node region 1210 can be detected at the transmitting node (e.g., in gNB 1200 for DL ​​traffic) by paired LBT. This may not be detected at the transmitting node (e.g., in gNB 1200 for DL ​​traffic) by unpaired legacy LBT. Region 1212 can be an exposed region in which the exposed node problem may occur. Region 1214 in FIGS. 15A and 15B may indicate the remaining / still hidden node region, which may be smaller than the hidden node area of, for example, legacy LBT.

[0276] FIG. 15B includes a legend that can be used, for example, with respect to FIGS. 15A, 15B, 16, 17A, and 17B.

[0277] In some embodiments, paired LBTs in the direction of the receiving node and the opposite direction can be performed using different beam patterns and / or different ED thresholds, for example, to maximize the number of detected hidden node terminals. For example, if the beam pattern is not adjustable at the transmitting node but can be predefined, multiple beams can be used for LBT in the opposite direction. Adjustment of the beam pattern, number of beams, and / or ED threshold for LBT in the opposite direction can be performed at the transmitting node. This can be done if information and / or system configuration of the Rx beam of the receiving node is available. If the information and / or system configuration is not available, the adjustment can be dynamically based on feedback messages from the receiving node (e.g., HARQ feedback and / or other messages related to interference and / or signal level reports).

[0278] For LBT in the opposite direction, at the transmitting node, the beam (θ sup , G sup,m ) can be used. The beam pattern (e.g., main lobe beamwidth and / or main lobe gain) used at the transmitting node for LBT in the opposite (e.g., complementary) direction can be set as a function of system parameters and / or reports from the receiving node, for example, when a single opposite direction can be used.

[0279] FIG. 16 illustrates an example of the effect of beam optimization used at a transmitting node for LBT in a single opposing direction, according to some embodiments. In the example of FIG. 16, the single opposing direction can be the DL access direction, pointing from the gNB 1300 toward the UE 1302. When a single opposing (e.g., complementary pair) direction is used and / or the beam is configurable, the objective can be to maximize the number of resolved hidden nodes while keeping the number of exposed regions limited (as illustrated in FIG. 16). This can be achieved by using a main lobe beamwidth (e.g., θ ) that is larger for LBT in the receiving node direction and than the main lobe beamwidth used for data transmission. sup >θ Tx ) can be achieved by (θ Rx >θ Tx ), it can be done if the Rx beamwidth of the receiving node is not larger than the Tx beamwidth (θ Rx <θ Tx ), which is achieved by using a main lobe beamwidth that is smaller than the main lobe beamwidth used for LBT in the direction of the receiving node and for data transmission (e.g., θ sup <θ Tx ) can be achieved by the design (e.g., optimal design) by considering the characteristics of the Rx beam of the receiving node (θ Rx , G Rx,m ), transmitter-receiver distance, propagation characteristics (e.g., path loss exponent and / or carrier frequency), noise power, and / or the product of the AP 1304 transmit power and the AP main lobe gain. To find a value (e.g., an optimal value), the transmitting node may calculate the antenna pattern characteristics (e.g., θ Rx , G Rx,m ), and / or transmitter-receiver distance, which can be estimated based on measurement reports from receiving nodes (e.g., as a result of an initial discovery procedure or as a result of continuing neighbor beam measurements).

[0280] θ sup If increases (e.g., increases too much), new areas of exposure to the transmitting node may appear above and / or below the Rx beam of the receiving node. The transmitting node may detect interferers that would not normally be detected. The main lobe beamwidth (θ sup ) optimization may involve trade-offs.

[0281] In some embodiments, a (eg, optimal) value for the main lobe beamwidth may be provided, as will be described in more detail herein.

[0282] In some embodiments, the number of beams used at the transmitting node for LBT in the opposite direction may be determined, eg, optimized.

[0283] The number of beams used at the transmitting node for LBT in the opposite (e.g., complementary) direction can be set as a function of system parameters and / or reports from the receiving node. This can be done when multiple opposite (e.g., complementary) directions are used (e.g., when the set of beams at the transmitter is predefined and will not be dynamically changed). An example of this is illustrated in FIG. 15B. As seen in FIG. 15B (where three beams are shown as an example), the number of beams for LBT in the opposite (e.g., complementary) direction can be set to maximize the number of resolved hidden nodes while keeping the number of exposed nodes limited.

[0284] The parameters (eg, the same parameters) of the technique discussed herein (beam parameter optimization) can be used to find the optimal number of beams to be used for LBT in the opposite direction.

[0285] In some embodiments, determination (eg, optimization) of the ED threshold used at the transmitting node for LBT in the opposite direction may be provided.

[0286] For LBT in the opposite direction, the ED threshold used at the transmitting node can be set as a function of system parameters and / or reports (e.g., HARQ feedback and / or other messages) from the receiving node. The ED threshold can be adjusted as a function of parameters and / or measurement reports from the receiving node. The ED threshold can be adjusted for paired LBT with a single opposite direction and for paired LBT with multiple opposite directions.

[0287] The optimization can minimize the number of exposed nodes while maintaining the region of avoided hidden nodes. The ED threshold can be selected so that the interfering AP (e.g., only) within the Rx beam region of the receiving node is detected. In Figures 15A and 15B, increasing the ED threshold can avoid exposed nodes within the newly exposed node region 1212.

[0288] 17A and 17B illustrate examples of the effect of increasing the ED threshold for LBT in opposite directions. Fig. 17A illustrates an example of the effect of increasing the ED threshold for LBT in a single opposite direction using an optimized beam shape, according to some embodiments. Fig. 17B illustrates an example of the effect of increasing the ED threshold for LBT in multiple opposite directions using predefined beams, according to some embodiments.

[0289] In Figures 17A and 17B, (e.g., optimal) results are shown for the cases of performing (a) a single LBT in an opposite (e.g., complementary) direction (e.g., 180°, see Figure 17A), or (b) multiple LBTs in multiple opposite (e.g., complementary) directions (e.g., 160°, 180°, 200°, see Figure 17B).

[0290] 17A and 17B, the ED threshold design (e.g., optimal ED threshold design) is determined based on the characteristics of the Rx beam (e.g., θ Rx , G Rx,m ), transmitter-receiver distance, propagation characteristics (e.g., path loss exponent and / or carrier frequency), noise power, and / or the product of the AP 1402 transmit power and the AP 1402 main lobe gain. leg denotes the ED threshold of the LBT in the direction of the receiving node (which may be -72 dBm for LTE-LAA with a bandwidth of 20 MHz), and TH sup are in opposite (e.g., complementary) directions (e.g., LBT dir+180 ) indicates the ED threshold. For example, the farther a receiving node is from the transmitting node (e.g., as the transmitter-receiver distance increases), the lower the TH sup can be increased further. sup The (e.g., optimal) value of is in the opposite direction (e.g., LBT dir+180 ) overlaps with the resolved node region 1404. Generally, in some embodiments, a positive detection region refers to a region where the signal level is high enough that detection can be, for example, guaranteed. sup The analytical formula for is explained in more detail below.

[0291] In one example, the ED threshold for the LBT in the opposite direction can be configured to be greater than the ED threshold used for the LBT in the direction of the receiving node (e.g., THsup >TH leg ). This can be done if the information of the receiving node is not available at the sending node.

[0292] 18 is an example flow diagram 1500 for adjusting parameters associated with LBT in the opposite direction, according to some embodiments. The flow diagram 1500 illustrated in FIG. 18 can be applied in cases where parameters for LBT in the opposite direction are adjusted (e.g., optimally adjusted) based on information from the receiving node and / or system configuration. In this case, the discovery information may include, for example, characteristics of the Rx beam of the receiving node.

[0293] Referring to FIG. 18 , in some embodiments, upon establishment of a connection between a transmitting node (denoted as “TX”) and a receiving node (denoted as “RX”), discovery information can be transmitted from the receiving node to the transmitting node at 1501. The discovery information can include parameters established during the discovery procedure or established based on continuing proximity measurements. The parameters can include, for example, the main lobe beamwidth and main lobe gain of the receiving node's Rx beam. Upon reception at the transmitting node, at 1502, the transmitting node can adjust parameters for the LBT in the opposite direction, for example, when it receives from the receiving node discovery procedure-related measurements or measurements based on continuing proximity measurements, estimated transmitter-receiver distances, and knowledge of the system configuration (e.g., noise power, propagation characteristics, etc.). The LBT parameter adjustment can include adjustment of the beam pattern and / or number of beams and / or the opposite direction ED threshold. The adjustment can be performed per receiving node and can be used, for example, for all LBTs associated with transmissions toward a particular receiving node, such as the RX receiving node in FIG. 18 . A transmitting node may use different parameter settings for LBT in the opposite direction for different receiving nodes.

[0294] When data is available for transmission at the transmitting node at 1504, the transmitting node may perform LBT in a paired direction, such as toward the receiving node and in the opposite direction, at 1506, using LBT adjustments in the opposite (e.g., complementary) direction. If the LBT in the paired direction indicates that the channel is clear at 1508, the transmitting node may begin data transmission toward the receiving node at 1510. The receiving node may receive and decode the transmitted data at 1512. When data is again available for transmission at the transmitting node at 1514, the transmitting node may repeat the LBT procedure performed at 1506 prior to data transmission to determine whether the channel is clear at 1516. If the LBT in the paired direction indicates that the channel is busy at 1518, the transmitting node may postpone data transmission and wait for the DIFS+backoff time before the next channel access attempt at 1520. The transmitting node may then attempt to access the channel again, and when the LBT in the paired direction indicates that the channel is clear at 1522, the transmitting node may begin data transmission at 1524. The receiving node may receive the transmitted data and decode it at 1526.

[0295] In some embodiments, the parameters of the paired LBT (e.g., ED threshold, beam pattern, and / or the number of beams used for LBT in opposite (e.g., complementary paired) directions) can be dynamically adapted based on receiver feedback. For example, the parameters can be dynamically updated when the Rx beam information and / or transmitter-receiver distance of the receiving node is unknown at the transmitting node.

[0296] In an example, the adaptation of the LBT parameters for the opposite (e.g., complementary) direction can be performed based on HARQ feedback from the receiving node. In this case, for example, the adaptation can be based on statistics of the number of received HARQ NACKs. The transmitting node can determine that the receiving node is in an interference-limited scenario, which means that the main lobe beamwidth (θ sup ) and use more beams for LBT in the opposite direction and / or increase the ED threshold (TH sup ) can be decreased, for example, to increase the area of ​​the detected hidden nodes.

[0297] This can improve transmitter-receiver link performance, for example, by reducing interference-limited conditions and back-off times.

[0298] Signals and / or measurement reports from the receiving node can be used by the transmitter node to adapt the LBT parameters for the opposite (e.g., complementary pair) direction, including, but not limited to, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Channel State Information (CSI), Interference Measurement (IM), and / or Reference Signals (CRS, DM-RS), etc.

[0299] 19 is an example flow diagram 1600 for dynamically adjusting parameters for LBT in the reverse direction, according to some embodiments. In the example of FIG. 19, parameters can be dynamically adjusted based on a report from a receiving node that can indicate an interference-limited condition. For example, as shown in FIG. 19, an indicator of the interference-limited condition (e.g., a NACK message) can be used. Generally, in some embodiments, a receiving node (denoted as “RX”) can use various messages that indicate an interference-limited condition, including, for example, a NACK message that can indicate an interference-limited condition, an explicit message that can indicate an interference-limited condition, and / or any other useful message (e.g., an RSRP, RSRQ, CSI, and / or IM report, etc.) that allows a transmitting node (denoted as “TX”) to determine that decoding would have been unsuccessful due to interference.

[0300] Referring to FIG. 19 , when data is available for transmission at a transmitting node at 1601, the transmitting node may perform LBT in a paired direction, such as toward the receiving node and in the opposite direction, at 1602. If the LBT in the paired direction indicates that the channel is clear at 1604, the transmitting node may start data transmission toward the receiving node at 1606. If the receiving node determines that decoding is unsuccessful because interference is received at 1608, the receiving node may transmit a message (e.g., a NACK message) indicating the interference (denoted as an “interference-limited indicator”) at 1610. The transmitting node may adjust parameters for the LBT in the opposite direction upon receiving a message related to an interference-limited situation or upon determining an interference-limited situation based on a signal quality message from the receiving node at 1612. The parameter adjustment may include increasing the beam pattern, increasing the number of beams, and / or reducing the ED threshold. The adjustments can be updated dynamically, in real time, based on reports from the receiving node and used for the LBT associated with subsequent transmissions.

[0301] As further shown in FIG. 19 , if there is interference, the transmitting node may attempt the next LBT (using the adjustment performed in 1612) in the paired direction at 1614. The results of the LBT in the paired direction may indicate that the channel is busy at 1616. Thus, at 1618, the transmitting node may postpone data transmission and wait for the DIFS+backoff time before the next channel access attempt. At 1620, the transmitting node may attempt to access the channel again (by performing an LBT) and sense that the channel is clear. At 1622, the transmitting node may begin data transmission. At 1624, the receiving node may receive and decode the transmitted data. When data is again available for transmission at the transmitting node at 1626, the transmitting node may again perform an LBT using the adjusted parameters to determine whether the channel is clear prior to data transmission at 1628. If the adjusted LBT in the paired direction indicates the channel is clear at 1630, the transmitting node may begin data transmission at 1632. The receiving node may receive and decode the transmitted data at 1634.

[0302] As mentioned above, the "interference limit indicator" message can be a NACK or any other message that can relate to an interference limit situation experienced at the receiving node, or that can enable the transmitting node to determine that an interference limit situation has occurred.

[0303] In some embodiments, the transmitting node can use information (e.g., sensed power / energy) captured during the LBT in the opposite (e.g., complementary) direction to, for example, optimize a transmission / reception strategy, etc. For example, the transmitting node can use a multi-threshold ED procedure for the LBT in the opposite (e.g., complementary) direction, perform adaptive MCS selection, and / or implement a power control mechanism that can be adjusted as a function of the sensed power during the LBT in the opposite (e.g., complementary) direction.

[0304] The power sensed during the LBT in the opposite (e.g., complementary) direction can be used to adjust the transmission and reception strategy. Strategy adjustment can include, for example, employing a multi-level ED threshold procedure for the LBT in the opposite direction such that only transmissions toward the receiving node are allowed, but transmissions from the receiving node toward the transmitting node (reverse direction) are not allowed, selecting a modulation and coding scheme (MCS) at the transmitting node for each power sensed during the LBT in the opposite / complementary direction, and / or adjusting power control at the transmitting node based on the power sensed during the LBT in the opposite direction.

[0305] The transmitting node may use a two-threshold ED procedure for the LBT in the opposite direction, where the two ED thresholds are TH1 and TH2, where TH1>TH2. If the power detected in the LBT in the opposite (e.g., complementary) direction exceeds TH1, the transmitting node may postpone transmission. If the power detected in the LBT in the opposite (e.g., complementary) direction exceeds TH2 but does not exceed TH1, the transmitting node may be allowed to transmit, but transmission from the receiving node (in the reverse direction) may not be allowed.

[0306] A two-threshold ED procedure for LBT in the opposite direction can be used to allow (e.g., still allow) transmission from the transmitting node to the receiving node, but not allow reverse link transmission. This can be due to perceived opposite-direction interference measurements. For example, in a double-threshold scheme, if the measured interference level exceeds a higher threshold for the opposite direction, the intended receiving node cannot be allowed to transmit uplink traffic. The receiving node can be allowed to receive data at a low transmission rate (which may have a low signal-to-interference-plus-noise ratio (SINR) due to received interference from an interfering node in the opposite direction). Transmission from the receiving node to the transmitting node (in the opposite direction) can be prevented, except for, for example, sending ACK / NACK. This can avoid generating interference to the AP and / or STAs. The ED threshold can indicate power control for transmissions from the receiving node toward the transmitting node.

[0307] The transmitting node can perform adaptive MCS selection, which can depend on the power level sensed in the LBT ED in the opposite direction. For example, if the LBT in the opposite direction indicates the channel as busy, even if the channel conditions on the transmitter-receiver link are favorable, the transmitting node can transmit at a lower MCS, which can be adapted based on the power sensed in the LBT in the opposite (i.e., complementary) direction. This can be performed in a way that decoding may be possible at the receiving node even if the receiving node is interfered with. Transmission from the transmitting node can be allowed because the transmitting node cannot interfere with the AP / STA.

[0308] The transmitting node can use the sensed power level in the LBT in the opposite direction to adjust its transmit power (e.g., power control). If the LBT in the opposite direction indicates the channel as busy, the transmitting node knows that there may be interference at the receiving node and can increase its transmit power (e.g., if feasible).

[0309] 20 is an example flow diagram 1700 for adjusting a transmission strategy based on LBT in the opposite direction, according to some embodiments. FIG. 20 illustrates features associated with a case where, after sensing that the channel is busy using LBT in the opposite direction, the transmission strategy at the transmitting node is adjusted based on the power / energy sensed during LBT in the opposite direction. In some embodiments, the transmitting node can adjust the MCS or transmit power accordingly, which can enable successful decoding at the receiving node.

[0310] Referring to FIG. 20 , when data is available for transmission at the transmitting node at 1701, the transmitting node may perform LBT in a paired direction, such as toward the receiving node and in the opposite direction, at 1702. If the LBT in the paired direction indicates that the channel is clear at 1704, the transmitting node may start data transmission toward the receiving node at 1706. The receiving node may receive and decode the transmitted data at 1708. When data is again available for transmission at the transmitting node at 1710, the transmitting node may again perform LBT in the paired direction at 1712, and as a result, may determine that the channel is busy at 1714. The transmitting node may adjust its transmission strategy (e.g., adjust its MSC and / or transmit power) based on the sensed power in the opposite direction at 1716. Thereafter, the transmitting node may start data transmission at 1718. At 1720, the receiving node may receive and decode the transmitted data.

[0311] In some embodiments, the techniques described herein can be combined. For example, an adaptive MCS can be combined with a multi-threshold ED procedure. The ED threshold can be TH1>TH2>TH3. If the power detected in the LBT in the opposite direction exceeds TH1, the transmitting node's transmission can be postponed. If the power detected in the LBT in the opposite direction exceeds TH2 but not TH1, the transmitting node's transmission can be allowed using an adapted MCS according to the sensed energy. Transmission from the receiving node cannot be allowed. If the power detected in the LBT in the opposite direction exceeds TH3 but not TH2, the transmitting node's transmission can be allowed using an adapted MCS according to the sensed energy. Transmission from the receiving node can be allowed using mandatory power control. If interference in the opposite direction to the intended LBT direction becomes higher than a (e.g., highest) threshold, the receiving node can be allowed to send ACK / NACK messages in the opposite direction because the duration of these messages may not be significant and has minimal impact on the interfering node. In this case, regular reverse link transmissions cannot be permitted.

[0312] The DL / UL MCS selection may be adapted to the measured interference and / or expected impact at the receiving node, for example, as described herein. The information exchanged between the transmitting and receiving nodes may be achieved via short messaging or a priori established default values ​​that may be known to the transmitting and receiving nodes.

[0313] The ED threshold can be determined using one or more of the following: TH1 can determine the lowest measurable power level. This level can be set as a CCA threshold level defined in the WiGig region or based on receiver sensitivity. The highest threshold can be set as a high threshold in the WiGig region when WiGig devices measure interference from non-WiGig waveforms. If CCA indicates that the channel is busy, the WiGig devices can back off transmitting their packets. The highest threshold level can be mapped to the minimum perceived SIR at the target (receiving) node. For example, in FIG. 17A, the gNB measures the power level of the AP and predicts the corresponding highest interference level at the UE that may be caused by the AP's packet transmission in the forward direction. The interference can be limited at the UE, and the SIR at the UE can be minimized. The highest threshold can be defined as a threshold that maps to a (e.g., minimum) MCS index selection that can be based on the predicted SIR at the UE, which can enable sustainable DL traffic from the gNB to the UE. It can be expected that the SIR at the UE can be (e.g., always) positive due to the distance between the interferer (e.g., AP) and the transmitting node (e.g., gNB), as shown in Figure 17A. The intermediate threshold can be set to reflect MCS selection based on (e.g., estimated) SIR variation at the intended receiving node.

[0314] Figure 21 is an example flow diagram 1800 associated with a multi-ED threshold implementation, according to some embodiments. Figure 21 illustrates a two-ED threshold procedure in which transmitter-to-receiver and receiver-to-transmitter transmission authorization / prohibition can be determined based on the power sensed during the LBT in opposite (e.g., complementary) directions and their relationship to two predefined ED thresholds. Figure 21 illustrates a feature associated with a multi-ED threshold implementation in which transmissions from the transmitting node to the receiver can be authorized, but transmissions from the receiver to the transmitting node cannot be authorized, which can be based on the power sensed during the LBT in the opposite direction. In the multi-ED threshold procedure, signaling can be used to indicate when transmissions in the reverse direction (receiver to transmitter) cannot be authorized.

[0315] 21 , when data is available for transmission at the transmitting node at 1801, the transmitting node may perform LBT in a paired direction, such as toward the receiving node and in the opposite direction, at 1802. If the transmitting node senses that the power in the opposite direction is lower than ED threshold 2 (hereinafter referred to as “ED TH2”) based on the performed LBT at 1804, the transmitting node may start data transmission toward the receiving node at 1806. At 1808, the receiving node may receive and decode the transmitted data. When data is again available for transmission at the transmitting node at 1810, the transmitting node may again perform LBT in the paired direction at 1812 and may sense that the power in the opposite direction exceeds ED TH2 but does not exceed ED threshold 1 (hereinafter referred to as “ED TH1”) at 1814. At 1816, the transmitting node may initiate data transmission, and at 1818, the receiving node may receive and decode the transmitted data. Thereafter, or approximately simultaneously with the data transmission, at 1820, the transmitting node may transmit an indicator to the receiving node that the receiving node is not authorized to transmit from the transmitting node (RX to TX).

[0316] When data is again available for transmission at the transmitting node at 1822, the transmitting node may repeat the LBT in the paired direction at 1824 and sense that the power in the opposite direction exceeds ED TH1 at 1826. As a result, the transmitting node may postpone data transmission at 1828 and wait for the DIFS+backoff time before the next channel access attempt. The transmitting node may perform another LBT in the paired direction at 1830 and sense that its power in the opposite direction is now lower than ED TH2 at 1832. In response, the transmitting node may begin data transmission at 1834. The receiving node may receive the transmitted data and decode it at 1836.

[0317] According to some embodiments, the ED threshold adjustment can be based on the angle of arrival (AoA) of the interfering signal. For example, when the transmitting node is a UE and the receiving node is a gNB, and the LBT beamwidth in the opposite direction cannot be reduced to match the gNB beamwidth (e.g., due to hardware limitations in the UE), the transmitting node can set the ED threshold for the LBT in the opposite direction as a function of the AoA of the interfering signal.

[0318] FIG. 22 illustrates an example of using angle-of-arrival estimation and varying ED thresholds for LBTs in opposite directions, according to some embodiments. For example, in FIG. 22, a signal from AP 1900 (also denoted “AP2”) arrives at UE 1902 at an AoA (AoA2), which may be different from the AoA (AoA1) of the signal from AP 1904 (also denoted “AP1”). AP 1904 may be within the Rx beam boresight of gNB 1906, but AP 1900 may not. In this situation, the ED threshold of the signal arriving from AoA2 may be greater than the ED threshold of the signal arriving from AoA1. The paired LBT at UE 1902 may prevent transmission in the presence of AP 1904 but may not prevent transmission in the presence of AP 1900.

[0319] In some embodiments, the LBT can receive assistance from the receiving node. For example, if the transmitting node does not have the capability to perform simultaneous LBT in one or more opposite (e.g., complementary) directions to the receiving node, the receiving node can assist the transmitting node in determining whether transmission is permitted. For example, if the transmitting node is a UE and the receiving node is a gNB (as in the configuration shown in FIG. 22), the UE may not be capable of performing simultaneous LBT in multi-directionality, and the gNB can assist the UE.

[0320] According to some embodiments, a receiving node (e.g., gNB) can perform LBT in the direction of a transmitting node (e.g., UE), and the transmitting node (UE) can perform LBT in the direction of the receiving node (gNB). The gNB can perform carrier sensing in the opposite direction, and coordination can involve both nodes (e.g., gNB and UE) to sense that the channel is idle, allowing data transmission from the UE to the gNB to begin.

[0321] 23 is an example flow diagram 200 illustrating LBT assistance from a receiving node, according to some embodiments. FIG. 23 illustrates features by which a receiving node (gNB) can provide LBT assistance to a transmitting node (UE).

[0322] In FIG. 23 , the UE may request gNB assistance after sensing a clear channel toward the gNB. More specifically, at 2001, the UE may transmit discovery information to the gNB. The discovery information may include an indication of whether the UE is capable of performing simultaneous multi-directional LBT. If the UE is not capable of performing simultaneous multi-directional LBT, assistance from the gNB is activated (at the gNB) at 2002. When data is available for transmission at the UE, at 2004, the UE may perform LBT in the direction of the receiving node (in the direction of the gNB) at 2006. If the LBT in the receive (RX) direction indicates that the channel is clear at 2008, the UE sends an assistance request to the gNB at 2010. The assistance request may be in the form of any suitable message indicating a request for LBT assistance from the receiving node. Upon receiving an assistance request from the UE, the gNB may perform LBT in the direction of the transmitting node (UE) (in the direction of the UE) at 2012, which may cover the opposite direction of the transmitting node (UE). If the gNB finds the channel clear in the transmit (TX) direction at 2014, the gNB may send an indication to the UE indicating a clear channel in that direction (e.g., using any appropriate message) at 2016. The UE may repeat the LBT in the RX direction at 2018, and if the UE senses the channel is clear at 2020, the UE may begin data transmission at 2022. The gNB may receive the transmitted data and decode it at 2024.

[0323] When data is again available for transmission at the UE at 2026, the UE may perform another LBT in the RX direction at 2028. If the LBT in the RX direction indicates that the channel is clear at 2030, the UE sends another assistance request to the gNB at 2032. In response, the gNB performs another LBT in the TX direction to cover the opposite direction of the UE at 2034. If the LBT in the TX direction indicates that the channel is busy at 2036, the gNB may postpone any transmission to the UE and wait for a DIFS+backoff time before the next channel access attempt at 2038. If the LBT in the TX direction indicates that the channel is clear at 2040, the gNB may begin transmitting an indication to the UE indicating a clear channel in that direction at 2042. At 2044, the UE may repeat the LBT in the RX direction so that, if the UE senses that the channel is clear at 2046, the UE begins data transmission at 2048. At 2050, the gNB may receive and decode the transmitted data.

[0324] In some embodiments, features associated with optimizing parameters of a transmitting node for LBT in the opposite direction may be provided.

[0325] More specifically, in some embodiments, a feature can be provided that optimizes the parameters of the transmitting node for the proposed paired LBT in the case where a single beam is used in a single opposite direction, e.g., dir+180°. The following example is described for DL ​​communication, gNB (transmitting node) to UE (receiver), but may also be applicable to UL communication. The gNB beam parameters for LBT in the opposite direction can be optimized in an attempt to maximize the number of resolved hidden nodes while avoiding excessive exposed nodes. The ED threshold at the gNB for LBT in the opposite (e.g., complementary) direction can be optimized so that the positive detection region for LBT in the opposite direction can overlap with the region of resolved hidden nodes. The path loss (PL) is

[0326]

number

[0327] where α is the path loss exponent that can take values ​​between 2 and 6, and f c where ∑ j = 1 , ∑ j = 2 , ...

[0328]

number

[0329] G T (j), P T (j), G R (i) may denote the transmit antenna gain at node j, the transmit power at node j, and the receive antenna gain at node i, respectively. The UE Rx beam area has a radius r and an angle θ directed towards the gNB. RxThe radius can be calculated as follows:

[0330]

number

[0331] N o W can denote the noise power, and G Tx,AP,m where P is the AP main lobe gain, Tx,AP refers to the AP transmission power. UE beamwidth θ Rx The APs within can be (eg, at least) r meters away from the UE in order not to interfere with it.

[0332] In some embodiments, the beam (θ sup , G sup,m ) can be optimized. Figure 24 illustrates an example of beamwidth adjustment for LBT in the opposite direction, according to some embodiments. This can maximize the number of resolved hidden nodes and avoid the creation of newly exposed nodes. This can be done by adjusting the main lobe beamwidth for LBT in the opposite direction so that it covers the Rx beam area of ​​the UE 2102, as shown in Figure 24. The angle of the gNB 2100 sector can be angled to allow it to cover the boundary of the UE Rx beam area. Antenna gain can be obtained from the beamwidth adjustment.

[0333] The closed-form expression for the main lobe beamwidth used for LBT in the opposite direction is

[0334]

number

[0335] d gNB-UEcan be the distance of the UE from the gNB, as shown in FIG. 24.

[0336] As discussed herein, the main lobe beamwidth and antenna gain can be directly related. An antenna pattern with the same beamwidth in the azimuth and elevation domains has

[0337]

number

[0338] where C can be a constant that depends on the type of 3D antenna pattern (e.g., elliptical, rectangular). sup,m θ may have a maximum value that depends on the number of antenna elements at the gNB. Tx The value of (gNB) is θ Rx The value of θ can be lower than the value of θ sup >θ Tx (i.e., achievable main lobe beamwidth).

[0339] If multiple predefined beams are used in multiple opposing directions (as shown in FIG. 15B), the gNB can select the number of beams that maximizes the area of ​​resolved hidden nodes. There will be no excessive exposed nodes.

[0340] θ (e.g., obtained using the techniques discussed herein) sup and G sup,m Given a fixed value of , the transmitting node (gNB) can adjust the ED threshold for the LBT in the opposite direction so that the positive detection region for the LBT in the opposite (e.g., complementary) direction can overlap with the region of the resolved hidden node (see FIG. 17A).

[0341]

number

[0342] This formula, which can be used to adjust the ED threshold for LBT in opposite directions, can be applied when multiple beams with predefined beam patterns (e.g., as shown in FIG. 17B) are used in multiple opposite (e.g., complementary) directions.

[0343] Although various embodiments have been described above, including embodiments directed to mitigating directional hidden node problems that may arise when operating in unlicensed bands with highly directional systems, for example, these embodiments are not exhaustive and additional variations, implementations, configurations, procedures, etc. are possible within the scope of this disclosure.

[0344] According to some embodiments, disclosed herein are methods, systems, and signaling for coordinated LBT mechanisms that enable spatial reuse in multiple unlicensed bands, such as in sub-6 GHz and / or mmWave unlicensed bands. In some embodiments, the methods disclosed herein provide coordination procedures, e.g., for use among nodes associated with the same or related RATs (Radio Access Technologies) and / or one or more operators (e.g., cellular / wireless carriers), to prevent (e.g., avoid) (or at least reduce the likelihood of) intra-RAT LBT blocking, e.g., while complying with or meeting LBT requirements or regulations in one or more unlicensed bands.

[0345] For example, uncoordinated LBT mechanisms between different nodes of the same RAT, which are generally capable of transmission coordination (or coordination of transmissions between nodes), can result in unnecessary LBT blocking, which can further result in poor channel utilization. Cellular networks are typically designed to enable reuse (e.g., reuse of radio resources (e.g., frequency, time, etc.)), e.g., perfect reuse, by utilizing several interference management techniques (e.g., adaptive rate control, power control, coordinated multipoint (CoMP), enhanced inter-cell interference coordination (eICIC), etc.) to mitigate inter-cell interference within nodes, e.g., of a single RAT (e.g., NR from a particular operator / radio carrier).

[0346] Thus, it may generally be unnecessary to block transmissions due to LBT between devices of the same RAT (e.g., nodes of the same RAT, and possibly of the same operator) that can coordinate for transmission in the unlicensed spectrum. However, regulations for the 5 GHz and 60 GHz unlicensed bands, for example, require the implementation of LBT.

[0347] 25A and 25B illustrate examples of LBT blocking for (A) nodes of different RATs and (B) nodes of the same RAT, respectively, according to some embodiments.

[0348] In the example of FIG. 25A, AP 2200 (also shown as "AP1") is accessing the channel and then blocks gNB 2202 (also shown as "gNB1") from transmitting during MCOT because gNB 2202 senses the channel as busy using LBT. Therefore, gNB 2202 needs to wait until AP 2200's transmission ends and the backoff procedure is complete, as shown in FIG. 25A. Then, when the channel is clear, gNB 2202 can finally access the channel. This is, for example, a typical procedure.

[0349] However, in FIG. 25B, gNB2204 (also shown as "gNB2"), which may be a node of the same RAT, e.g., the same operator as gNB2202's operator, is accessing the channel and blocks gNB2202's transmission due to linear transmission and LBT carrier sensing. In this case, gNB2202 needs to postpone transmission as shown in FIG. 25B when, under what may be typical cellular operation, a cellular network would normally allow full reuse in conjunction with an effective coordination strategy that can manage interference (e.g., at least between nodes of the same RAT and operator). In the example of FIG. 25B, LBT blocking may have adverse effects, such as hindering spatial reuse. Generally, in some embodiments, spatial reuse refers to enabling time and frequency resource utilization at different locations. In this regard, for example, interfering beams may prevent spatial reuse of radio resources (e.g., due to collisions).

[0350] To avoid the problem of LBT blocking of transmissions within nodes of the same RAT, solutions have been proposed to group neighboring TRPs and have them self-defer for joint channel access so that they no longer block each other, either by using reservation signaling or by the transmission itself.

[0351] However, a major challenge that the self-deferral technique may present is that during the self-deferral period, another node may access the channel. Also, note that while this technique addresses simultaneous access, it does not address the case where a node is already accessing the channel, and may block neighboring transmissions of nodes in the same RAT (e.g., as shown in Figure 25B).

[0352] For example, LBT blocking among nodes of the same RAT (and / or the same operator), which generally follow coordinated transmissions, remains a problem that needs to be solved in LAA. Some communication technologies, such as Wi-Fi and WiGig, employ contention so that LBT blocking is generally allowed and nodes do not also coordinate for transmission.

[0353] Therefore, improvements to LAA and NR-U (or 5G NR-based access to unlicensed spectrum), which typically follow a scheduled approach, may be desirable.

[0354] According to some embodiments, an adjusted LBT signaling is disclosed. In some embodiments, the LBT adjustment can be performed to adjust the backoff procedure, for example, assuming that transmission adjustment can be applied after the LBT adjustment using some of the already available techniques (e.g., CoMP, eICIC, etc.).

[0355] In some embodiments, when a gNB (e.g., gNB1 shown in FIG. 25B) detects that a node occupying a channel is, for example, a node using the same RAT (e.g., gNB2 shown in FIG. 25B), the gNB can send a message to the node, for example, via an Xn interface as in NR (or an X2 interface as in LTE), to request an LBT coordination (referred to herein as an "LBT-C-RQ"), which seeks to avoid unnecessary LBT blocking. Figure 26 illustrates an example scenario of an LBT coordination according to some embodiments.

[0356] A node receiving the LBT-C-RQ (e.g., gNB 2300 (also denoted "gNB2") of FIG. 26 receiving LBT-C-RQ 2306 from gNB 2302 (also denoted "gNB1") via Xn interface 2304) can either accept the LBT-C-RQ or reject it. If accepted, in some embodiments, the accepting node returns an acceptance (e.g., in the form of any suitable acceptance message) that includes or is accompanied by one or more ways in which, for example, LBT adjustments to complete the backoff will or can be performed. Furthermore, in some embodiments, the acceptance may also indicate a start time for transmission adjustments and a transmission adjustment strategy that can be applied after the LBT backoff procedure is completed.

[0357] In some embodiments, detection of the presence of same-RAT devices may be based on the assumption that same-RAT nodes are generally capable of decoding their own RAT messages (e.g., PDCCH or eDRTS (highly directional RTS)).

[0358] Once a node gains access to the channel, it can perform transmission adjustments in multiple domains, such as time, frequency, space, power, and / or rate. However, it should be noted that in some embodiments, some level and / or form of transmission adjustment may be necessary to complete the LBT backoff procedure. In some embodiments, LBT adjustments can be made in either the frequency domain or the time domain. Figures 27A and 27B illustrate examples of LBT adjustments in (A) the frequency domain and (B) the time domain, respectively, according to some embodiments.

[0359] Additionally, in some embodiments, LBT adjustments may be made within (eg, only within) the MCOT to improve fairness to other RATs.

[0360] For frequency domain LBT adjustment (see FIG. 27A), in some embodiments, the LBT backoff is completed and then any suitable transmission adjustment strategy for transmission is used. Initially, upon receiving LBT-C-RQ 2400 and, for example, an indication of a backoff time from gNB1, gNB2 can release some resource blocks (RBs) or BWPs (bandwidth parts) for a period of time and indicate such to gNB1 through a frequency-related adjustment accept (message) 2402 (referred to herein as "LBT-CAf"). gNB2 can also provide an indication of parameters such as, for example, but not limited to, the resources to be released, the transmission adjustment strategy, the start time of the transmission adjustment, and / or the time until the MCOT limit. Some or all of these parameters can be indicated in LBT-CA-f 2402 or transmitted separately from LBT-CA-f 2402. Thereafter, upon receiving the information / message from gNB2, gNB1 can change from wideband LBT to BWP LBT (or subband LBT) within the indicated frequency resources (or BWP) released by gNB2.

[0361] In the exemplary frequency-domain LBT adjustment procedure described above, a gNB1 with the release of some RBs and the ability to perform BWP LBT on those RBs (i) allows the gNB1 to complete the LBT backoff procedure in accordance with applicable unlicensed spectrum regulations, and (ii) can then transmit by leveraging spatial reuse (e.g., by fully utilizing spatial reuse within the allocated BWP).

[0362] For time-domain LBT adjustment (see FIG. 27B), in some embodiments, an exemplary procedure for completing LBT backoff (b) and then using any suitable transmission adjustment strategy for transmission can be, for example, as follows:

[0363] Initially, upon receiving LBT-C-RQ 2404 and, e.g., an indication of a backoff time, gNB2 may release OFDM symbols that may be needed to complete the LBT backoff and indicate so to gNB1 through a time-related adjustment accept (message) 2406 (referred to herein as "LBT-CAt"). LBT-CA-t 2406 may also indicate parameters such as, e.g., without limitation, a start time for the transmission adjustment, a transmission adjustment strategy, and / or a time until the MCOT limit. Alternatively, some or all of these parameters may be provided separately from LBT-CA-t 2406. Thereafter, gNB1 may continue to use wideband LBT upon receiving the information / message from gNB2.

[0364] In some embodiments, in the exemplary time-domain LBT coordination procedure described above, transmission coordination can be performed, for example, by leveraging spatial reuse within the entire (or full) bandwidth (BW). However, compared to LBT frequency-domain coordination, in LBT time-domain coordination, it may be possible that another node may access (or at least attempt to access) the channel in the released time resources (see FIG. 27(B)). In some embodiments, when this or a similar type of access occurs, it can be treated as a form of "intra-RAT shared MCOT." In this case, the released time can be as low as a few microseconds (e.g., 25 μs, as in shared MCOT), which can be sufficient to complete the LBT.

[0365] According to an example embodiment, in time-domain and / or frequency-domain LBT coordination, the time remaining in backoff (e.g., in gNB1) can be transmitted simultaneously or together with LBT-C-RQ 2400 and / or 2404, respectively, so that gNB2 can appropriately configure the released resources (e.g., BWP or some time symbols) for gNB1 to complete the LBT. Also, together with or together with LBT-CA, the BWP and / or released time symbols to complete the backoff are specified, as well as information regarding the start time + coordination strategy + end time (MCOT limit), which can, for example, allow full reuse.

[0366] For example, based on values ​​related to NR-U operation, the implementation of the proposed LBT adjustment can be feasible for NR-U. The MCOT for the unlicensed 60 GHz band takes a value of 9 ms. See, for example, Non-Patent Document 2. Assuming a numerology of μ=4 (i.e., SCS=240 kHz), this results in 16×9=144 slots in the MCOT. Therefore, gNB1 has 144 opportunities to decode the PDCCH from gNB2, if decodable. A CCA slot for the 60 GHz band (e.g., according to Non-Patent Document 2) is a 5 microsecond CCA slot. Therefore, following this example, gNB1 can access the channel by decoding the PDCCH from gNB2 instead of waiting for 9 ms + backoff (X × 5 microseconds) (e.g., at most one slot, i.e., 62.5 μs + adjustment + backoff (X × 5 microseconds) for μ=4).

[0367] Advantageously, some embodiments described herein not only provide spatial reuse but can also reduce channel access delay.

[0368] Additionally, 5G NR utilizes an Xn interface (see, e.g., Xn interface 2304 in FIG. 26), which is used, for example, for communication between base stations (e.g., gNB-gNB). Some embodiments disclosed herein further provide signaling associated with LBT coordination that is also compatible with or suitable for use of the Xn interface.

[0369] In one example embodiment, coordinated LBT request signaling (referred to herein as "LBTRS") is disclosed. The LBTRS can be transmitted over Xn by a gNB that detects a busy channel, for example, due to the presence of nodes from a RAT shared with the gNB. The LBTRS can include (but is not limited to) the following information: (i) a request for intra-RAT LBT coordination within the MCOT (LBT-C-RQ), (ii) a remaining backoff time, (iii) a requesting gNB identity, and / or (iv) a requested gNB identity.

[0370] In an example embodiment, a coordinated LBT enable signaling (referred to herein as "LBTES") is disclosed. The LBTES can be transmitted over Xn by a gNB occupying a channel and receiving an LBTRS. Furthermore, the LBTES can include (but is not limited to) the following information: (i) a frequency-domain LBT adjustment acceptance to complete backoff (LBT-CAf), (ii) released resources in the frequency domain (e.g., BWP), (iii) a time-domain LBT adjustment acceptance to complete backoff (LBT-CAt), (iv) a start time of transmission adjustment, (iv) a transmission adjustment strategy (time, frequency, power, spatial, CoMP, etc.), (v) a time until MCOT limit, (vi) a requesting gNB identity, and / or (vii) a requested gNB identity.

[0371] In the above signaling, for example, the use of a requesting gNB identity (e.g., the ID of gNB1) and a requested gNB identity (e.g., the ID of gNB2) in the LBTRS allows, for example, coordination between specific gNBs rather than being directed towards all nodes of a given RAT (e.g., all gNBs).

[0372] Additionally, in some embodiments, when a gNB gains access to a channel, it may inform nearby gNBs (e.g., gNBs of the same RAT) whether the channel is busy / accessed by another gNB, e.g., of the same RAT, e.g., through a channel access indicator to facilitate detection on the part of nearby gNBs.

[0373] In contrast to other proposed approaches to LBT adjustment (e.g., the self-postponement approach before channel access, as described above), some embodiments disclosed herein may provide signaling to request an adjustment of the LBT backoff procedure (in time or in frequency (e.g., BWP)), for example, after detecting an ongoing transmission of a TRP of the same RAT that can be adjusted for transmission. In some disclosed embodiments, the kind or type of accepted LBT backoff adjustment (e.g., which, if indicated, may imply a change from wideband LBT to BWP LBT) may further be signaled, allowing the node to self-postpone, for example, in the entire BW or only in the BWP, for transmission adjustment.

[0374] Furthermore, some embodiments disclosed herein provide ways to ensure fairness among different RATs in unlicensed bands / spectrum.

[0375] More specifically, to ensure fair multi-RAT coexistence in unlicensed mmWave bands, for example, two LBT solutions are being considered for NR-U in 3GPP: (i) omniLBT (also referred to herein as "omniLBT"), and (ii) directional LBT (also referred to herein as "dirLBT"). The two solutions differ in terms of the type of physical carrier sensing. OmniLBT senses omnidirectionally, while dirLBT senses in a directional manner towards the intended RX. See, for example, Non-Patent Document 3.

[0376] However, these approaches may have some drawbacks. Figure 28A illustrates an example of the behavior of omnidirectional LBT, according to some embodiments. Figure 28B illustrates an example of the behavior of directional LBT for directional transmission / reception, according to some embodiments.

[0377] In directional transmissions, omni-directional LBT can cause overprotection because transmissions can be prevented even when signals are detected from directions that would not create harmful interference to the intended RX (e.g., the exposed node problem shown in FIG. 28A (top) (non-linear transmission case 2450) for TX2-RX2, which would be able to reuse spectrum but is prevented by omni-directional LBT). In many implementations, omni-directional LBT may only be appropriate when transmissions are linear in space, as shown, for example, in FIG. 28A (bottom) (linear transmission case 2452).

[0378] In contrast, directional LBT does not create excessive protection because it can typically sense only the spatial direction in which a transmission is made (see Figure 28B (top) (non-linear transmission case 2454)). However, in directional LBT, other ongoing nearby transmissions will not be detected. Therefore, the directional hidden node problem can cause interference because TX1's transmission is within RX2's antenna boresight (linear transmission case 2456), as shown in Figure 28B (bottom).

[0379] Thus, the approaches discussed above can result in (1) an omniLBT-based scheme that is overprotective and does not allow spatial reuse, and (2) a dirLBT-based scheme that allows spatial reuse but may have some hidden node problems. These tradeoffs are illustrated in Figures 28A and 28B for non-linear (top) and linear (bottom) transmissions. Therefore, in some implementations, it may be advantageous to utilize an LBT scheme in a more optimal manner.

[0380] Furthermore, it can be shown, for example, via Monte Carlo simulations, that the best physical carrier sense scheme (at least in terms of performance) among directional LBT, paired LBT (also referred to herein as "pairLBT"), and omnidirectional LBT varies according to the network density and the beamwidth employed. For example, at low network density, directional LBT may be sufficient, while at high network density, omnidirectional LBT may be sufficient. Similarly, at narrow beamwidths, directional LBT may be sufficient, while at wide beamwidths, omnidirectional LBT may be sufficient. Furthermore, the complexity of a given LBT mode can be taken into account when selecting an LBT mode. Generally, for example, omnidirectional LBT may be considered to be the simplest LBT.

[0381] According to some embodiments, the methods and systems disclosed herein provide an LBT switching mechanism that addresses at least some of the shortcomings associated with the use of omnidirectional LBT and / or directional LBT, for example, in the case of directional transmission and reception, as illustrated in Figures 28A and 28B.

[0382] In some embodiments, switching from directional LBT to omni-directional LBT can occur when directional LBT senses the channel as idle but a hidden node problem occurs. In some systems, the switching can be performed based on HARQ-ACK feedback. For example, if multiple HARQ-ACK feedbacks are NACKs, the transmitting node (TX) can switch to omni-directional LBT. Otherwise, it can continue with directional LBT. Note that NACKs are typically determined when incorrect reception occurs (e.g., the control channel was decoded but the data could not be decoded) or when no feedback is received (e.g., due to LBT, e.g., the control channel could not be decoded or the NACK feedback was not correctly decoded or blocked).

[0383] The switch from directional LBT to omnidirectional LBT can be performed based on information such as, for example, HARQ-ACK feedback. More specifically, in some embodiments, the transmitting node can average information collected for the DL (downlink) case. In an exemplary embodiment, a transmitting node in the DL case, such as a gNB, can collect HARQ-ACK feedback from UEs and can decide to switch from directional LBT to omnidirectional LBT when the number of NACKs exceeds a certain threshold within a given time period or over a certain number of received HARQ feedbacks.

[0384] In some embodiments, a switch from omni-LBT to directional LBT can occur when omni-LBT prevents some (e.g., a predetermined number or a number above a certain threshold) accesses to the channel, such as due to exposed nodes, rather than due to interference conditions. In some embodiments, the LBT switch can be performed based on reported information from the receiving node (RX) according to the following example mechanism described below.

[0385] In an exemplary mechanism, the TX (transmitting node) can track channel accesses whose status is determined to be "busy" by the omniLBT and can store the specific times of those determinations. When the TX is able to successfully access the channel, it can transmit information about the time of the blocked channel access to the RX. Meanwhile, the RX can perform continuous ED (energy detection) carrier senses using the antenna configuration or beam it would normally use for data reception from the TX while in radio resource control (RRC) connected mode and store the results in memory. Based on the received blocked channel access times from the TX, the RX can compare those times with the ED carrier sense results and respond to the TX if the RX senses signal energy greater than a threshold using the antenna configuration or beam used for data reception from the TX.

[0386] Based on the response from RX, TX can proceed as follows: (i) If the presence of other nearby transmitting nodes appears to be the primary cause of the hindered channel access, TX can continue to use omniLBT (e.g., decide to do so autonomously (or at least partially autonomously) or be instructed to do so by RX); (ii) If other nearby transmitting nodes do not appear to be the primary cause of the hindered channel access, TX can switch to dirLBT (e.g., decide to do so autonomously (or at least partially autonomously) or be instructed to do so by RX).

[0387] Note that in some embodiments, switching from omniLBT to, for example, dirLBT may require new information, such as information to measure the level of overprotection of the omniLBT or the amount of missed transmission opportunities. Thus, in some embodiments, if the switch is to proceed, a procedure can be used to measure the omniLBT overprotection and thus enable switching the sensing scheme, for example, to dirLBT.

[0388] FIG. 29 illustrates a procedure 2500 for omni-directional LBT over-protection detection according to some embodiments. Such a procedure may involve, by way of example, (i) sensing information 2506, e.g., slot and / or OFDM symbol (OS) index (e.g., {x, y, z}, as shown in FIG. 29 ), transmitted from a transmitting node 2502 (also shown as “TX”) during which channel access was attempted (and found to be busy), and / or (ii) a response 2508 to the sensing information 2506 transmitted from a receiving node 2504 (also shown as “RX”). In this regard, multiple response options may be available, some examples of which include one or more of: (1) the slot / OS index in which the sensed node was detected; (2) the percentage of attempts 2508 (as shown in FIG. 29 ) during which the channel was found to be busy on the RX side; and / or (3) a switching indicator 2510 (as shown in FIG. 29 ).

[0389] Based on the message exchange, as shown in FIG. 29 for example, the TX can know if it sensed something that the RX did not (in which case it can, for example, switch LBT strategies). If both the transmitting and receiving nodes sensed the transmission, the TX can continue to use omniLBT. For example, in some embodiments, the sensing information 2506 from the TX can include the index of the slot or OFDM symbol when the channel was sensed and determined to be busy using omniLBT. The RX can then determine how much of the time that the TX determined the channel as busy was also determined as busy by the RX. The RX can respond to the TX with a value containing this information, for example, as a percentage or fraction (see, e.g., percentage 2508 in FIG. 29 (left side)), or can send a switch indicator (see, e.g., switch indicator 2510 in FIG. 29 (right side)) to inform the TX to switch LBT modes.

[0390] In the DL case, reporting (3) (see above) has lower overhead but provides less detailed information about the TX side (e.g., UE side) than (1) and (2). In some embodiments, a base station (e.g., eNB) can switch LBT modes for all connected UEs in a cell. UE reporting based on formats (1) and (2) can provide additional information to the base station relative to format (3) for making a switching decision, but using these UE reporting formats may require higher signaling overhead than (3), for example. In some embodiments, for a particular Tx beam, the number of received switching indicators may be required to exceed a certain threshold, for example, to perform a switch. In the UL case, because a TX (e.g., UE) may communicate with different TRPs through different beams, reporting (1), (2), and / or (3) may be equivalent because no averaging is required at the TX (e.g., UE).

[0391] Furthermore, in some embodiments, the proposed mechanisms used to switch LBT strategies may include, for example, (i) switching from omniLBT to pairLBT (a soft change), (ii) switching from omniLBT to dirLBT (an abrupt change when omniLBT is determined to result in more missed channel access opportunities than necessary), or (iii) switching from pairLBT to dirLBT.

[0392] Furthermore, in some embodiments, the LBT switching procedure can be extended to cases involving various access schemes for NR, such as DL (scheduled) access scheme, SUL (scheduled, UL grant-based) access scheme, and / or AUL (UL grant-free) access scheme. Because DL and SUL typically have higher priority than AUL for channel access, the LBT scheme can be constrained to be omnidirectional for some types of channel access and network densities, e.g., AUL in dense networks, by not enabling the LBT switching procedure from omniLBT to any other type of LBT.

[0393] According to some embodiments, a method and system for modifying a contention window size (CWS) for directional transmissions in case of collisions is disclosed herein.

[0394] In LAA, the CWS is updated based on HARQ feedback. For example, if 80% of the HARQ feedback for one reference subframe is NACK, the CWS is increased; otherwise, it is not increased. Based on observed (data) collisions in the NR-U framework, it may be desirable to implement some form of CWS adaptation procedure. However, for example, in the case of directional transmission, the CWS adaptation procedure adapted for use in LAA may not be appropriate, and a different CWS adaptation procedure may be required.

[0395] Figures 30A and 30B illustrate an example of CWS adaptation in a multi-cell scenario. For example, as shown in the example of Figure 30A, the LBTs (represented by respective beams 2604 and 2606) of gNB 2600 and gNB 2602 (also denoted as "gNB1" and "gNB2," respectively) are not linear, and both gNB 2600 and gNB 2602 may listen to the channel during DIFS. Because one gNB's transmission may not be heard or may be impossible to hear by the other gNB, the channel is sensed as free to both gNB 2600 and gNB 2602. Thus, both gNBs access the channel at approximately the same time, and a collision occurs. In this case, if the same CWS adaptation procedure used for LAA is applied, both gNBs may exponentially increase CWS. Both gNBs listen again during DIFS and again sense the channel as free, resulting in another collision. Therefore, the same procedure will continue repeatedly. In such a case, increasing the CWS based on the HARQ procedure may not be appropriate because the LBT is not linear (as shown in Figure 30A).

[0396] The described CWS adaptation procedure may only be appropriate when the respective LBTs of both gNB 2600 and gNB 2602 (represented by respective beams 2608 and 2610) form a straight line, e.g., the scenario shown in FIG. 30B. When gNB 2600 and gNB 2602 see each other, they will likely back off and randomize their channel access by adapting their respective CWSs.

[0397] According to some embodiments, for example, in the case of simultaneous or concurrent transmissions from multiple gNBs, when the transmission directions are not linear with each other (e.g., as shown in FIG. 30A), the UE can enforce a backoff procedure to randomize the gNBs' access to the channel. In some embodiments, the UE can perform channel sensing in the direction of the receive beam and also in the opposite direction intended to cover the gNB transmit beam direction, and if the channel is sensed busy for a duration exceeding a certain threshold, the UE can send a message to the gNB requesting backoff. In some embodiments, such a message can comprise a new message or can be included as an additional parameter in the eDCTS sent in response to the eDRTS received from the gNB.

[0398] In some other embodiments, CWS adaptation at the gNB can be based on statistical paired sensing at the target UE in the direction of the transmit beam. This can include channel sensing in the direction of the receive beam and also in the opposite direction intended to cover the gNB transmit beam direction. In some embodiments, the target UE can suggest the most appropriate CWS across the transmit beam line based, for example, on the percentage of busy slots sensed during the sensing phase.

[0399] Also, in some other embodiments, CWS adaptation, e.g., based on HARQ NACK / ACK, can be used, e.g., where the NACK includes directional information from sensing indicating whether there is an interference source that is in line with the transmit beam and such a source may be causing collisions.

[0400] Generally, as addressed herein, transmissions in mmWave frequencies may require, for example, directional Tx-Rx (transmit-receive) operation. Additionally, transmissions in unlicensed frequencies may require channel sensing, for example, to determine whether the channel is clear. For example, simply performing directional LBT and RTS / CTS in the intended transmit / receive direction may not be sufficient in some implementations to accurately determine channel utilization status, for example, due to the potential presence of directional hidden nodes. Figure 35 illustrates an example scenario 2850 including directional RTS / CTS in NR-U-NR-U coexistence in the presence of an interfering node.

[0401] As explained above, the methods and systems disclosed herein, according to some embodiments, address challenges related to how to secure unlicensed channels using directional Tx-Rx in the presence of hidden nodes.

[0402] FIG. 36 is a flowchart illustrating a method for reserving a directional channel, according to some embodiments. According to some embodiments, the method can be performed by a receiving node, such as a wireless transmit / receive unit (e.g., UE). As shown in FIG. 36, in step 2900, the receiving node receives a directional transmission request (DRTS) message from a transmitting node. In step 2902, the receiving node transmits a directional transmission clear (DCTS) message using one or more first beams, with at least one first beam pointed in a first direction toward the transmitting node. In step 2904, the receiving node determines a second direction, the second direction being different from the first direction. Then, in step 2906, the receiving node transmits at least one additional DCTS message using one or more second beams, with at least one second beam pointed in a second direction toward a potential interfering node.

[0403] FIG. 37 is a flowchart illustrating another method for reserving a directional channel, according to some embodiments. According to some embodiments, the method may be performed by a receiving node. As shown in FIG. 37 , in step 3000, the receiving node receives a highly directional transmission request message from a transmitting node. In step 3002, the receiving node transmits a highly directional transmission confirmation message using one or more first beams, where at least one first beam is pointed in a first direction toward the transmitting node. Then, in step 3004, the receiving node transmits at least one additional highly directional transmission confirmation message using one or more second beams, where at least one second beam is pointed in a second direction toward a potential interfering node, where the second direction is a direction different from the first direction.

[0404] In some embodiments, as described herein above, the methods and systems disclosed herein use enhanced directional messaging (e.g., eDCTS and / or eDCTS-to-self messages), e.g., directed toward potential interfering nodes (e.g., dominant interfering nodes). In some embodiments, the eDCTS-to-self may include data and eDCTS-to-self scheduling information, and / or the location and orientation of the interfering node. Furthermore, in some embodiments, the eDCTS-to-self may be targeted, e.g., toward the direction of a potential (e.g., known) interfering node (e.g., obtained from a gNB or via measurements).

[0405] In some embodiments, eDCTS-to-self transmissions can be repeated once every T (or every given time period) (e.g., based on a minimum CCA duration). In some embodiments, eDCTS-to-self can include remaining MCOT duration information. For example, with reference to FIG. 31, the MCOT can begin, for example, immediately before the eDRTS is transmitted or immediately after a (e.g., successful) LBT, and can include multiple periods T. FIG. 38 illustrates an example series of transmissions 3100 including eDRTS and eDCTS-to-self transmissions, according to some embodiments. FIG. 38 shows an example of an MCOT duration 3102 and periodic eDCTS-to-self transmissions within the MCOT.

[0406] FIG. 39 illustrates an example interference scenario using eDRTS, eDCTS, and multiple eDCTS-to-self procedures 3200 in NR-U-NR-U coexistence, according to some embodiments. In some embodiments, for example, the example transmission configuration shown in FIG. 38 can be applied to the scenario illustrated in FIG. 39. As shown in FIG. 39, gNB 3202 and UE 3204 (also denoted as "gNB2" and "UE3," respectively) can be nodes that can potentially cause interference to UE 3208 (also denoted as "UE1"). As shown in FIG. 39, gNB 3206 (also denoted as "gNB1") can transmit an eDRTS message 3210 for reception by UE 3208. UE 3208 can then transmit an eDCTS message 3212 using a beam pointed toward gNB 3206. The UE 3208 may also transmit multiple eDCTS-to-self messages 3214 and 3216 directed toward potential interfering nodes. As illustrated, the UE 3208 may transmit the eDCTS-to-self message 3214 using a beam directed toward the gNB 3202 and may transmit the eDCTS-to-self message 3216 using a beam directed toward the UE 3204.

[0407] As discussed above, potential hidden nodes can interfere with directional transmission and reception in unlicensed frequencies. According to some embodiments, as described herein, a receiving UE can perform directional channel access using enhanced messaging in multiple directions to reserve a channel between the UE and a transmitting node (e.g., a gNB).

[0408] In some embodiments, a method performed by a UE to reserve a channel may include receiving an highly directional request to send (eDRTS) message from a transmitting node, transmitting an highly directional clear to send (eDCTS) message in a first direction toward the transmitting node, and transmitting an additional eDCTS message in a second direction toward a potential interfering node.

[0409] In some embodiments, the second direction is different from the first direction.

[0410] In some embodiments, the UE may determine the second direction (of a potential interfering node) from an eDRTS message or a listen-before-talk (LBT) assessment.

[0411] In some embodiments, the UE may transmit the eDCTS message multiple times within the MCOT.

[0412] Additionally, various other and related embodiments have been described herein above.

[0413] According to some embodiments, a method in a receiving device for addressing potential interference from one or more potentially hidden network nodes during directional transmission and reception between a receiving node and a transmitting node on an unlicensed frequency may include the receiving node performing directional channel access using enhanced messaging in multiple directions to reserve a directional channel between the receiving node and the transmitting node. In some embodiments, the receiving node is a UE and the transmitting node is a base station (e.g., a gNB).

[0414] According to some embodiments, a method performed by a device, such as a UE, for directional channel access is disclosed. Such a method includes the device transmitting multiple channel reservation signals in one or more directions different from a direction of an intended receiver of a subsequent data transmission. In some embodiments, the method may further include receiving a first type of message (e.g., an highly directional request to send (eDRTS)) in a first direction and transmitting a second type of message (e.g., an highly directional clear to send (eDCTS)) in the first direction and a second direction. In some embodiments, the first direction and the second direction are different, and at least one of the first direction and the second direction is a direction toward a potential interfering node. In some embodiments, the direction toward the potential interfering node can be indicated by the first type of message. In some embodiments, the second type of message is an highly directional clear to send to itself (eDCTS to itself) message. In some other embodiments, the second type of message is an eDCTS, which can be repeatedly transmitted by a device multiple times within a given duration, such as a maximum channel occupancy time (MCOT).

[0415] According to some embodiments, a method performed in a transmitting node includes performing a first listen-before-talk (LBT) in a direction of a transmit beam directed toward a receiving node, determining whether a channel is busy based on the performed first LBT in the direction of the transmit beam, performing a second LBT in a reverse direction, and determining whether an interfering signal is detected from the reverse direction. In some embodiments, the method may further include postponing transmission if an interfering signal is detected. Postponing transmission may include, for example, waiting a backoff time and again performing the first and second LBTs. Furthermore, various parameters may be adaptively selected, including, for example, a beamwidth configuration, a number of predefined beams, an energy detection threshold, and / or an MCS selection for the communication link.

[0416] According to some embodiments, a method for an NR-U and WiGig coexistence system is disclosed, in which, for example, a device (e.g., a UE) can adaptively set transmit power and / or number of repetitions in a direction toward an interferer until the interferer backs off.

[0417] According to some embodiments, a method is disclosed for use among multiple nodes to enable resource reuse in an unlicensed spectrum by using listen-before-talk (LBT) coordination. In such a method, the unlicensed spectrum can be a sub-6 GHz or mmWave band. Furthermore, the multiple nodes can be associated with a given radio access technology (RAT) and / or a given operator.

[0418] According to some embodiments, a method for coordinated listen-before-talk (LBT) signaling between nodes may include receiving, at a first node, a request for LBT adjustment from a second node; and, upon accepting the request at the first node, providing an indication to the second node indicating a given LBT adjustment to complete an LBT backoff. In some embodiments, the method may further include the second node completing the LBT backoff. In still other embodiments, the method may further include using transmission coordination between the first node and the second node for transmission by the second node when the LBT backoff is completed and the second node has access to the channel. The first node and the second node may be associated with a given radio access technology (RAT), such as the same RAT, and / or a given operator, such as the same operator. Furthermore, the first node and the second node may be coordinated for transmission in an unlicensed band, such as the 5 GHz or 60 GHz band. In yet another embodiment, the method for coordinated LBT signaling may further include providing, by the first node to the second node, at least one of a start time of the transmission adjustment and a transmission adjustment strategy to be used after the LBT backoff is completed.

[0419] In the method for coordinated LBT signaling, the LBT coordination can be performed within a maximum channel occupancy time (MCOT). Further, the first node and the second node can be 5G nodes, such as a first gNB and a second gNB.

[0420] In some embodiments, the given LBT adjustment to complete the LBT backoff can be a frequency-domain LBT adjustment. For example, upon receiving a request for an LBT adjustment at a first node, the first node releases frequency resources, the first node provides an indication to the second node indicating the released frequency resources, and upon receiving the indication from the first node, the second node changes from using wideband LBT to using subband LBT within the indicated released frequency resources. The released frequency resources can be indicated in the frequency-related adjustment acceptance, can include a bandwidth part (BWP), and / or can be released for a given time period. Furthermore, in some embodiments, a remaining backoff time can be transmitted by the second node simultaneously with or together with the request for the LBT adjustment, thereby enabling the first node to configure the released frequency resources according to the remaining backoff time.

[0421] In some embodiments, the given LBT adjustment for completing the LBT backoff may be a frequency-domain LBT adjustment. For example, upon receiving a request for the LBT adjustment at a first node, the first node releases time resources for completing the LBT backoff, and the first node provides an indication of the released time resources to the second node. Upon receiving the indication from the first node, the second node continues to use wideband LBT. The released time resources may be indicated in the time-related adjustment acceptance and / or may include one or more OFDM symbols. Furthermore, in some embodiments, the remaining backoff time may be transmitted by the second node simultaneously with or together with the request for the LBT adjustment, thereby enabling the first node to configure the released time resources according to the remaining backoff time.

[0422] According to some embodiments, a method includes providing signaling associated with listen-before-talk (LBT) adjustment that is suitable for use over a 5G Xn interface. In some embodiments, the signaling associated with the LBT adjustment may include adjusted LBT request signaling (LBTRS). The LBTRS may be transmitted over the Xn interface by a gNB that detects a busy channel, for example, due to the presence of a node that shares a radio access technology (RAT) with the gNB. Furthermore, the LBTRS may include (i) a request for intra-RAT LBT adjustment within a maximum channel occupancy time (MCOT), (ii) a remaining backoff time, (iii) an identification of the gNB requesting the intra-RAT LBT adjustment, and / or (iv) an identification of the gNB requested for the intra-RAT LBT adjustment.

[0423] In some embodiments, the signaling associated with the LBT adjustment may further include adjusted LBT enable signaling (LBTES). The LBTES may be transmitted over the Xn interface by the gNB occupying the channel and receiving the LBTRS. Furthermore, the LBTES may include (i) a frequency-domain LBT adjustment acceptance to complete backoff, (ii) an indication of released resources in the frequency domain, (iii) a time-domain LBT adjustment acceptance to complete backoff, (iv) a start time for the transmission adjustment, (v) a transmission adjustment strategy, (vi) a time until a maximum channel occupancy time (MCOT) limit, (vii) an identification of the gNB requesting the intra-RAT LBT adjustment, and / or (viii) an identification of the gNB requested for the intra-RAT LBT adjustment.

[0424] According to some embodiments, a method includes switching between at least two different modes of listen-before-talk (LBT) in an unlicensed spectrum. In some embodiments, multiple radio access technologies (RATs) coexist in the unlicensed spectrum. Furthermore, in some embodiments, the switching is performed for directional transmission and / or reception. Still further, the switching can be disabled for a given type of channel access scheme associated with NR (New Radio).

[0425] The at least two different types of LBT may include omnidirectional LBT and directional LBT, and the switching may include (i) switching from omnidirectional LBT to paired LBT, (ii) switching from omnidirectional LBT to directional LBT, or (iii) switching from paired LBT to directional LBT.

[0426] In some embodiments, the switch includes switching from omni-directional LBT to directional LBT when omni-directional LBT prevents a given number of accesses to the channel, such as due to an exposed node rather than due to interference.

[0427] In other embodiments, the switching includes switching from omni-directional LBT to directional LBT, which includes the transmitting node tracking channel accesses for which the omni-directional LBT determined a status of "busy" and saving the time corresponding to the determination, the transmitting node transmitting information regarding the time of the prevented channel access to the receiving node upon accessing the channel, the receiving node comparing the received prevented channel access time from the transmitting node with the results of continuous ED (energy detection) carrier senses performed at the receiving node, and the receiving node notifying the transmitting node of the results of the comparison. In some embodiments, based on the notification from the receiving node, the transmitting node continues to use omni-directional LBT or switches to directional LBT.

[0428] According to some embodiments, a method for changing a contention window size (CWS) for directional transmission includes a user device, such as a user equipment (UE), requesting a backoff from a base station, such as a gNB.

[0429] According to some embodiments, a method for modifying a contention window size (CWS) for directional transmissions in a base station (e.g., a gNB) is disclosed, the method being based on paired sensing at a target user device (e.g., user equipment (UE)).

[0430] According to some embodiments, a method for dynamic downlink / uplink switching configuration per beam pair link (BPL) includes, for example, using periodic advanced directional transmit enable-to-self (eDCTS-to-self) transmissions. In some embodiments, during data transmission, the transmitter or receiver or both can periodically transmit multiple eDCTS-to-self messages to keep the directional channel reserved.

[0431] Although features and elements have been described herein in particular combinations, those skilled in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. Additionally, the methods described herein can be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, internal and removable disks, magnetic media such as magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer. [Industrial Applicability]

[0432] The present invention can be used in communications.

Claims

1. A method implemented by a first node, comprising: conducting a first listen-before-talk (LBT) toward a second node in a first LBT directional mode between an omnidirectional LBT mode and a directional LBT mode; transmitting a first message to the second node, the first message including first sensing information on the first LBT-based channel; receiving a second message from the second node, the second message including information related to the first sensing information; selecting a second LBT directional mode between the omni-directional LBT mode and the directional LBT mode based on the second message; A method for providing the above.

2. The method of claim 1 , wherein the first sensing information on the channel includes a slot index in which the channel was sensed.

3. The method of claim 1 , wherein the second message includes a slot index sensed by a third node.

4. 2. The method of claim 1, wherein the second message includes a percentage of attempts during which the channel was found to be busy by the second node.

5. The method of claim 1 , wherein the second message includes an indication of switching from the first LBT directional mode to the second LBT directional mode.

6. a processor, a transmitter, a receiver and a memory; conducting a first listen-before-talk (LBT) toward a second node in a first LBT directional mode between an omnidirectional LBT mode and a directional LBT mode; Sending a first message to the second node, the first message including first sensing information on the first LBT-based channel; receiving a second message from the second node, the second message including information related to the first sensing information; Selecting a second LBT directional mode between the omnidirectional LBT mode and the directional LBT mode based on the second message. A first node configured to:

7. The first node of claim 6 , wherein the first sensing information on the channel includes a slot index in which the channel was sensed.

8. The first node of claim 6 , wherein the second message includes a slot index sensed by the third node.

9. 7. The first node of claim 6, wherein the second message includes the percentage of attempts during which the channel was found to be busy by the second node.

10. The first node of claim 6 , wherein the second message includes an indication of switching from the first LBT directional mode to the second LBT directional mode.

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