TW201939913A - Synchronization signal and paging for new radio-unlicensed (NR-U) band communications - Google Patents

Abstract

Methods, devices, and systems using a synchronization signal (SS)/Physical Broadcast Channel (PBCH) block are disclosed herein. In an example, a wireless transmit/receive unit (WTRU) may detect an SS/PBCH block. The WTRU may then obtain one or more indications regarding a joint synchronization signal block (SSB) index and a time shift from the detected SS/PBCH block. In an example, one or more indications may be obtained from an SS in the detected SS/PBCH block. In another example, one or more indications may be obtained from a PBCH in the detected SS/PBCH block. Further, the WTRU may derive at least one of frame timing information, slot timing information and symbol timing information based on the obtained joint SSB index and time shift. Also, the WTRU may obtain timing information for detection of a channel access indicator (CAI), an SSB indication or both. Further, the WTRU may perform SSB measurements.

Description

Unlicensed New Radio (NR-U) Bandwidth Communication Sync Signal and Paging

Cross-reference to related applications

This application claims the benefits of U.S. Provisional Application No. 62 / 619,673, which was filed on January 19, 2018, and U.S. Provisional Application No. 62 / 716,077, which was filed on August 8, 2018, which is incorporated by reference as in this application Fully proposed.

Targets emerging 5th generation (5G) wireless systems based on general requirements outlined by the International Telecommunication Union-Radiocommunications Group (ITU-R), Next Generation Mobile Network (NGMN), and 3rd Generation Partnership Project (3GPP) A wide variety of use cases can be portrayed as enhanced mobile broadband (eMBB), large machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Different use cases may focus on different requirements, such as higher data rates, higher spectral efficiency, low power and higher energy efficiency, lower latency, and higher reliability. A wide range of spectrum from 700 million hertz (MHz) to 80 gigahertz (GHz) is considered to be useful in a variety of deployment scenarios. As the carrier frequency increases, severe path loss may become severely limited in its ability to ensure adequate coverage. Transmission in millimeter-wave systems may also face non-line-of-sight losses, such as diffraction loss, penetration loss, oxygen absorption loss, leaf surface loss, and so on. During the initial access, the base station and the wireless transmit / receive unit (WTRU) may need to overcome these high path losses and discover each other. Using tens or even hundreds of antenna elements to generate one or more beamforming signals can provide an effective way to compensate for severe path loss due to providing significant beamforming gain. Beamforming techniques may include digital beamforming, analog beamforming, and hybrid beamforming.

Cell search is a procedure by which the WTRU can obtain time and frequency synchronization with a cell and can detect the cell identity (ID) of the cell. Long-term evolution (LTE) synchronization signals can be transmitted in the 0th and 5th sub-frames of each radio frame and can be used for time and frequency synchronization during initialization. As part of the system acquisition procedure, the WTRU can sequentially synchronize to the orthogonal frequency division multiplexing (OFDM) symbol, time slot, sub-frame, half-frame, and radio frame based on the synchronization signal.

When the terminal is in RRC_IDLE mode, paging can be used for network-initiated connection establishment. In LTE, the same mechanism used for downlink data transmission on the downlink shared channel (DL-SCH) can be used and the mobile terminal can assign monitoring L1 / L2 control messaging for the downlink scheduling related to paging. Since the location of the mobile terminal is usually unknown at the cell level, paging messages are usually transmitted between multiple cells in a so-called tracking area.

This application discloses a method, device, and system using a synchronous signal (SS) / physical broadcast channel (PBCH) block. In one example, a WTRU can detect SS / PBCH blocks. The WTRU may then obtain one or more indications about the joint synchronization signal block (SSB) index and time offset from the detected SS / PBCH block. In one example, one or more indications may be obtained from the SS in the detected SS / PBCH block. In another example, one or more indications may be obtained from the PBCH in the detected SS / PBCH block. In addition, the WTRU may derive at least one of frame timing information, time slot timing information, and symbol timing information based on the obtained joint SSB index and time offset. In addition, the WTRU can obtain timing information for detecting channel access indicator (CAI), SSB indication, or both. Then, if the WTRU successfully detects one or both of the CAI and SSB indications, the WTRU may derive the time position of the SSB based on one or both of the detected CAI and SSB indications. Therefore, the WTRU may perform SSB measurements for the SSB of the actual transmission. In the event that the WTRU fails to detect at least one of the CAI and SSB indications, the WTRU may search for and measure all SSBs during the SSB scan. For example, the WTRU may search for all SSB time locations during the SSB scan. The WTRU may also measure all SSBs received during the SSB scan.

In another example, the CAI may have the status of a pre-talk listen (LBT) procedure for all SSB transmissions during the SSB scan. In another example, the CAI may have the status of one LBT procedure per sync signal block group (SSBG). In addition, there can be interruptions between SSBGs. In another example, the CAI may have the status of one LBT program in each SSB. In addition, gNB can perform a wide-beam LBT procedure for SSBGs in a Synchronous Signal Burst Set (SSBS). The gNB may indicate to the WTRU the execution of this procedure.

FIG. 1A is a diagram illustrating an example communication system 100 that can implement one or more of the disclosed embodiments. The communication system 100 may be a multiple access system that provides multiple wireless users with content such as voice, data, video, messaging, and broadcasting. The communication system 100 can enable multiple wireless users to access such content by sharing system resources including wireless bandwidth. For example, the communication system 100 may use 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 tail unique word DFT extended OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtering OFDM, and filter bank multi-carrier (FBMC), etc. Wait.

As shown in FIG. 1A, the communication system 100 may include a wireless transmission / reception unit (WTRU) 102a, 102b, 102c, 102d, RAN 104/113, CN 106/115, a public switched telephone network (PSTN) 108, the Internet Circuit 110 and other networks 112, however it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each WTRU 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, any WTRU 102a, 102b, 102c, 102d may be referred to as a "station" and / or "STA", which may be configured to transmit and / or receive wireless signals, and may include user equipment (UE ), Mobile station, fixed or mobile subscriber unit, subscription-based unit, pager, mobile phone, personal digital assistant (PDA), smart phone, laptop, small laptop, personal computer, wireless sensor, Hotspot or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMD), vehicles, drones, medical devices and applications (such as remote surgery), industrial devices and applications (such as Robots and / or other wireless devices operating in an industrial and / or automated processing chain environment), consumer electronics devices, and devices operating on commercial and / or industrial wireless networks, among others. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

The communication system 100 may further include a base station 114a and / or a base station 114b. Each base station 114a, 114b may be configured to facilitate access to one or more communication networks (e.g., CN 106/115) by wirelessly having a wireless interface with at least one of the WTRUs 102a, 102b, 102c, 102d. , Internet 110, and / or other networks 112). For example, the base stations 114a and 114b may be base transceiver stations (BTS), node B, e-node B, local node B, local e-node B, gNB, NR node B, website controller, access point (AP) , And wireless routers. Although each base station 114a, 114b is described as a single element, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

The base station 114a may be part of the RAN 104/113, and the RAN 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 and so on. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies called cells (not shown). These frequencies can be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. Cells can provide wireless service coverage for specific geographic areas that are relatively fixed or are likely to change over time. Cells can 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, that is, one for each sector of the cell. In one embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of a cell. For example, by using beamforming, signals can be transmitted and / or received in a desired spatial direction.

The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d through an air interface 116, where the air interface 116 may be any suitable wireless communication link (such as radio frequency (RF) , Microwave, centimeter wave, micro wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

More specifically, as described above, the communication system 100 may be a multiple access system, and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, base stations 114a and WTRUs 102a, 102b, 102c in RAN 104/113 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish airborne Interface 115/116/117. 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 UL packet access (HSUPA).

In one embodiment, base stations 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which may use long-term evolution (LTE) and / or advanced LTE (LTE -A) and / or Advanced LTA Pro (LTE-A Pro) to establish the air interface 116.

In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may use a new type of radio (NR) to establish the air interface 116.

In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access (eg, using the dual connectivity (DC) principle). As such, the air interface used by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNB and gNB).

In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (ie, wireless fidelity (WiFi)), IEEE 802.16 (Global Interoperable 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 Information for GSM Evolution Rate (EDGE) and GSM EDGE (GERAN) and so on.

The base station 114b in FIG. 1A may be a wireless router, a local Node B, a local eNode B, or an access point, and may use any appropriate RAT to facilitate wireless connections in a local area, such as a business premises, house, vehicle, Campuses, industrial facilities, air corridors (for example for drone use), roads, and more. In one embodiment, the base station 114b and the WTRUs 102c, 102d may establish a wireless local area network (WLAN) by implementing a radio technology such as IEEE 802.11. In one embodiment, the base station 114b and the WTRUs 102c, 102d may establish a wireless personal area network (WPAN) by implementing a radio technology such as IEEE 802.15. In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish picocells by using a cellular-based RAT (eg, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) Yuan or femtocell. As shown in FIG. 1A, the base station 114b can be directly connected to the Internet 110. Thus, the base station 114b does not need to access the Internet 110 via the CN 106/115.

RAN 104/113 may communicate with CN 106/115, which may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more WTRUs 102a, 102b, 102c, 102d. Any type of network. The data can have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN 106/115 can provide call control, billing services, mobile location-based services, pre-paid calling, internet connection, video distribution, etc., and / or can perform advanced security functions such as user authentication. Although not shown in Figure 1A, it should be understood that the RAN 104/113 and / or CN 106/115 may communicate directly or indirectly with other RANs that use the same RAT or different RATs as the RAN 104/113. For example, in addition to being connected to RAN 104/113 using NR radio technology, CN 106/115 can also communicate with other RAN (not shown) using GSM, UMTS, CDMA 2000, WiMAX, E-UTRA or WiFi radio technologies .

CN 106/115 may also act as a gateway for WTRUs 102a, 102b, 102c, 102d to access PSTN 108, Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network that provides simple legacy telephone service (POTS). The Internet 110 may include a protocol using a common communication protocol such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet Protocol family. A system of globally connected computer networks and devices. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service operators. For example, network 112 may include another CN connected to one or more RANs, where the one or more RANs may use the same RAT or different RATs as RAN 104/113.

Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (eg, WTRUs 102a, 102b, 102c, 102d may include multiple transceivers communicating with different wireless networks on different wireless links) . For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may use cellular-based radio technology, and with a base station 114b that may use IEEE 802 radio technology.

FIG. 1B is a system diagram illustrating an example WTRU 102. FIG. As shown in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmitting / receiving element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, and a removable Memory 132, power supply 134, global positioning system (GPS) chipset 136, and other peripheral devices 138. It should be understood that, while remaining consistent with embodiments, the WTRU 102 may also include any sub-combination of the aforementioned elements.

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 associated with a DSP core, a controller, and a microcontroller , Special integrated circuit (ASIC), field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), state machine, etc. The processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, and the transceiver 120 may be coupled to the transmitting / receiving element 122. Although FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated into one electronic component or chip.

The transmitting / receiving element 122 may be configured to transmit or receive signals to or from a base station (eg, base station 114a) via the air interface 116. For example, in one embodiment, the transmitting / receiving element 122 may be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, the transmitting / receiving element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmitting / receiving element 122 may be configured to transmit and / or receive both RF and optical signals. It should be understood that the transmitting / receiving element 122 may be configured to transmit and / or receive any combination of wireless signals.

Although the transmit / receive element 122 is described as a single element in FIG. 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may use MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmitting / receiving elements 122 (eg, multiple antennas) for transmitting and receiving radio signals through the air interface 116.

The transceiver 120 may be configured to modulate a signal to be transmitted by the transmitting / receiving element 122 and to demodulate a signal received by the transmitting / receiving element 122. As described above, the WTRU 102 may have multi-mode capabilities. Accordingly, the transceiver 120 may include multiple transceivers that allow the WTRU 102 to communicate with multiple RATs, such as NR and IEEE 802.11.

The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (such as a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may Receive user input from speakers / microphone 124, keypad 126, and / or display / touchpad 128 (such as 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. In addition, the processor 118 may access information from and store data in any suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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, and the like. In other embodiments, the processor 118 may access signals from those memories that are not physically located in the WTRU 102, and store data in these memories, as examples, which may be located on a server or a home computer (not shown).

The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power for other components in the WTRU 102. The power source 134 may be any suitable device that powers the WTRU 102. For example, the power source 134 may include one or more dry battery packs (such as nickel-cadmium (Ni-Cd), nickel-zinc (Ni-Zn), nickel-hydrogen (NiMH), lithium-ion (Li-ion), etc.), solar cells, and Fuel cells and more.

The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (eg, longitude and latitude) related to the current location of the WTRU 102. GPS chipset 136 information WTRU 102 may receive location information from base stations (eg, base stations 114a, 114b) that add or replace GPS chipset 136 information via air interface 116, and / or based on information from two or more nearby locations The timing of the signal received by the base station determines its position. It should be understood that while maintaining compliance with the embodiments, the WTRU 102 may obtain location information via any suitable positioning method.

The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connections. For example, peripherals 138 may include an accelerometer, electronic compass, satellite transceiver, digital camera (for photos and / or video), universal serial bus (USB) port, vibration device, TV transceiver, hands-free headset, Bluetooth ® modules, FM radio units, digital music players, media players, video game console modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, and events Tracker and more. The peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor Sensor, temperature sensor, time sensor, geographic sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, and / or humidity Sensor.

WTRU 102 may include a full-duplex radio, for which some or all signals (eg, associated with special sub-frames for UL (eg, for transmission) and downlink (eg, for reception) Reception or transmission may be parallel and / or simultaneous. A full-duplex radio may include signal reduction and / or substantial elimination via hardware (such as a choke) or signal processing by a processor (such as a separate processor (not shown) or by processor 118). Self-interfering interface management unit 139. In one embodiment, the WTRU 102 may include half-duplex to transmit and receive some or all signals (eg, associated with special sub-frames for UL (eg, for transmission) or downlink (eg, for reception)) Radio.

FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As described above, the RAN 104 may use the E-UTRA radio technology on the air interface 116 to communicate with the WTRUs 102a, 102b, 102c. The RAN 104 can also communicate with the CN 106.

The RAN 104 may include eNodeBs 160a, 160b, 160c, however it should be understood that while maintaining compliance with embodiments, the RAN 104 may include any number of eNodeBs. Each eNodeB 160a, 160b, 160c may include one or more transceivers on the air interface 116 to communicate with the WTRUs 102a, 102b, 102c. In one embodiment, eNodeB 160a, 160b, 160c may implement MIMO technology. Thus, for example, eNodeB 160a may use multiple antennas to transmit wireless signals to WTRU 102a, and / or receive wireless signals from WTRU 102a.

Each eNodeB 160a, 160b, 160c can be associated with a special cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. . As shown in FIG. 1C, the eNodeBs 160a, 160b, and 160c can communicate with each other through the X2 interface.

The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a service gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is described as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface, and may serve as a control node. For example, the MME 162 may be responsible for verifying the users of the WTRUs 102a, 102b, 102c, performing bearer initiation / deactivation, and selecting a special service gateway in the initial attach procedure of the WTRUs 102a, 102b, 102c, and so on. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) using other radio technologies such as GSM and / or WCDMA.

The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface. SGW 164 can generally route and forward user data packets to / from WTRUs 102a, 102b, 102c. SGW 164 can also perform other functions, such as anchoring the user plane in the handover procedure between eNodeBs, triggering paging when DL data is available to WTRU 102a, 102b, 102c, and managing and storing WTRU 102a, 102b, 102c Context and so on.

SGW 164 can be connected to PGW 166, which can provide WTRUs 102a, 102b, 102c with access to a packet-switched network (such as Internet 110) to facilitate WTRU 102a, 102b, 102c and IP-enabled devices Communication.

CN 106 can facilitate communication with other networks. For example, the CN 106 may provide WTRUs 102a, 102b, 102c with access to a circuit-switched network, such as PSTN 108, to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (such as an IP Multimedia Subsystem (IMS) server), and the IP gateway may serve as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide 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 operators.

Although the WTRU is described as a wireless terminal in Figures 1A to 1D, it should be thought that in some typical embodiments, such terminals and communication networks can use (eg, temporary or permanent) wired communications interface.

In the representative embodiment, the other network 112 may be a WLAN.

A WLAN in adopting an infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP can access other types of wired / wireless networks that either have an interface to a decentralized system (DS) or send traffic to and / or out of the BSS. Traffic originating from outside the BSS to the STA can be reached by the AP and delivered to the STA. Traffic originating from STAs and destined for destinations outside the BSS can be sent to APs for delivery to separate destinations. The traffic between STAs inside the BSS can be sent by the AP, for example, the source STA can send traffic to the AP and the AP can deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as point-to-point traffic. The point-to-point traffic can be sent between the source and destination STAs (eg, directly between them) using direct link setup (DLS). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z Channelized DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (for example, all STAs) that are inside the IBSS or that use the IBSS can directly communicate with each other. Here, the IBSS communication mode may sometimes be referred to as an "ad-hoc" communication mode.

When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the main channel. The main channel may have a fixed width (for example, a bandwidth of 20 MHz) or a width that is dynamically set through signaling. The main channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, what is implemented may be Carrier Sense Multiple Access (CSMA / CA) with collision avoidance (eg, in an 802.11 system). For CSMA / CA, STAs (such as each STA) including the AP can sense the main channel. The special STA may fall back if it is sensed / detected and / or determined that the main channel is busy by the special STA. In the designated BSS, there can be one STA (for example, only one station) to transmit between any reference timing.

High throughput (HT) STAs can use channels with a width of 40 MHz for communication (for example, by combining a main channel with a width of 20 MHz and adjacent or non-adjacent channels with a width of 20 MHz to form a channel with a width of 40 MHz).

Very High Throughput (VHT) STAs can support channels with widths of 20MHz, 40MHz, 80MHz, and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. A 160MHz channel can be formed by combining eight consecutive 20MHz channels or by combining two discontinuous 80MHz channels (this combination can be referred to as an 80 + 80 configuration). For the 80 + 80 configuration, after channel encoding, the data can be passed and passed through a segmented parser, which can split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time domain processing can be performed on each stream separately. The stream can be mapped on two 80MHz channels, and the data can be transmitted by the STA performing the transmission. On the receiver of the STA performing the reception, the above operations for 80 + 80 configuration can be reversed, and the combined data can be sent to the media access control (MAC).

802.11af and 802.11ah support sub-1GHz operation modes. Compared with those used in 802.11n and 802.11ac, channel operating bandwidth and carrier frequency have been reduced in 802.11af and 802.11ah. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication (eg, MTC devices in a macro coverage area). MTC may have certain capabilities, such as limited capabilities including support for (eg, support only) certain and / or limited bandwidth. The MTC device may include a battery, and the battery life of the battery is above a critical value (for example, to maintain a long battery life).

WLAN systems that can support multiple channels and channel bandwidth (for example, 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as the primary channel. The bandwidth of the main channel may be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the main channel may be set and / or limited by a STA that originates from all STAs operating in a BSS that supports the minimum bandwidth operation mode. In the example of 802.11ah, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operation modes, the STAs (such as MTC type) that support (for example, only support 1MHz mode) Device), the width of the main channel can be 1MHz. Carrier sensing and / or network allocation vector (NAV) settings can depend on the status of the primary channel. If the main channel is busy (for example, because the STA (which only supports 1MHz operating mode) transmits to the AP), then even if most of the frequency bands remain interleaved and available for use, the entire available frequency band can be considered busy.

In the United States, the available frequency bands available for 802.11ah are 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. According to the country code, the total bandwidth available for 802.11ah is 6MHz to 26MHz.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115 according to one embodiment. As described above, the RAN 113 may use NR radio technology on the air interface 116 to communicate with the WTRUs 102a, 102b, 102c. The RAN 113 can also communicate with the CN 115.

RAN 113 may include gNBs 180a, 180b, 180c, but it should be understood that while maintaining compliance with embodiments, RAN 113 may include any number of gNBs. Each gNB 180a, 180b, 180c may include one or more transceivers to communicate with the WTRU 102a, 102b, 102c via the air interface 116. In one embodiment, gNB 180a, 180b, 180c may implement MIMO technology. For example, gNB 180a, 180b may use a beamforming process to transmit and / or receive signals to and / or from gNB 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to the WTRU 102a and / or receive wireless signals from the WTRU 102a. In one embodiment, gNB 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers may be on the unlicensed spectrum, while the remaining component carriers may be on the licensed spectrum. In one embodiment, gNB 180a, 180b, 180c may implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a may receive cooperative transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

WTRUs 102a, 102b, 102c may use transmissions associated with scalable parameter configurations to communicate with gNB 180a, 180b, 180c. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may be different for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. WTRUs 102a, 102b, and 102c may use sub-frames or transmission time intervals (TTIs) of different or scalable lengths (eg, containing different numbers of OFDM symbols and / or continuously changing absolute time lengths) to communicate with gNB 180a, 180b, 180c for communication.

The gNB 180a, 180b, 180c may be configured to communicate with WTRUs 102a, 102b, 102c in a discrete configuration and / or a non-discrete configuration. In a discrete configuration, WTRUs 102a, 102b, 102c can communicate with gNB 180a, 180b, 180c without accessing other RANs (eg, eNodeB 160a, 160b, 160c). In a discrete configuration, WTRUs 102a, 102b, 102c may use one or more of gNB 180a, 180b, 180c as an action anchor. In a discrete configuration, WTRUs 102a, 102b, 102c can use signals in the unlicensed frequency band to communicate with gNB 180a, 180b, 180c. In a non-discrete configuration, WTRUs 102a, 102b, 102c will communicate / connect with gNB 180a, 180b, 180c while communicating / connecting with other RANs (e.g. eNodeB 160a, 160b, 160c). For example, WTRUs 102a, 102b, 102c may communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c in a substantially simultaneous manner by implementing the DC principle. In a non-discrete configuration, eNodeB 160a, 160b, 160c can act as an anchor for WTRU 102a, 102b, 102c, and gNB 180a, 180b, 180c can provide additional coverage and / or throughput in order to provide WTRU 102a, 102b, 102c provide services.

Each gNB 180a, 180b, 180c can be associated with a special cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network interception Cut, implement dual connectivity, implement interworking between NR and E-UTRA, route user plane data to user plane functions (UPF) 184a, 184b, and route to access and mobility management functions (AMF ) Control plane information for 182a, 182b, etc. As shown in Figure 1D, gNB 180a, 180b, 180c can communicate with each other through the X2 interface.

The CN 115 shown in FIG. 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 may include a data network (DN) 185a, 185b. Although each of the aforementioned elements is described as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by entities other than the CN operator.

The AMF 182a, 182b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface, and may serve as a control node. For example, AMF 182a, 182b can be responsible for verifying the users of WTRU 102a, 102b, 102c, support network truncation (such as processing different PDU conversations with different requirements), select special SMF 183a, 183b, manage registration area, terminate NAS Messaging, and mobile management. AMF 182a, 1823b can use network cut processing to customize the CN support provided to WTRU 102a, 102b, 102c based on the type of service used by WTRU 102a, 102b, 102c. For example, different network cuts can be established for different use cases, such as services that rely on ultra-reliable low latency (URLLC) access, rely on enhanced large-scale mobile broadband (eMBB) access Services, and / or services for machine type communication (MTC) access, etc. AMF 162 may provide for switching between RAN 113 and other RANs (not shown) using other radio technologies (eg, LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi) Control plane function.

SMF 183a, 183b can be connected to AMF 182a, 182b in CN 115 via N11 interface. SMF 183a, 183b can also be connected to UPF 184a, 184b in CN 115 via N4 interface. SMF 183a, 183b can select and control UPF 184a, 184b, and can configure traffic routing through UPF 184a, 184b. SMF 183a, 183b can perform other functions, such as managing and assigning UE IP addresses, managing PDU dialogs, controlling policy enforcement and QoS, and providing notification of downlink data, etc. PDU conversation types can be IP-based, non-IP-based, Ethernet-based, and so on.

UPF 184a, 184b can be connected to one or more gNBs 180a, 180b, 180c in RAN 113 via the N3 interface, which can provide WTRU 102a, 102b, 102c with access to a packet switched network (such as Internet 110) To facilitate communication between WTRUs 102a, 102b, 102c and IP-enabled devices. UPF 184, 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU conversations, handling user plane QoS, buffering downlink packets, and providing mobile anchor processing and many more.

CN 115 can facilitate communication with other networks. For example, CN 115 may include or may communicate with an IP gateway (such as an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. In addition, the CN 115 may provide 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 operators. In one embodiment, WTRUs 102a, 102b, and 102c can connect to local data through UPF 184a, 184b via the N3 interface to UPF 184a, 184b and the N6 interface between UPF 184a, 184b and DN 185a, 185b. Network (DN) 185a, 185b.

In view of Figures 1A to 1D and the corresponding descriptions of Figures 1A to 1D, one or more or all of the functions described here with respect to one or more of the following may be performed by one or more analog devices (not (Shown) to perform: WTRU 102a-d, base stations 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a- b. DN 185 ab and / or any other device (s) described herein. These simulation devices may be one or more devices configured to simulate one or more or all functions herein. For example, these simulated devices can be used to test other devices and / or analog networks and / or WTRU functions.

The simulated device may be designed to perform one or more tests on other devices in a laboratory environment and / or an operator network environment. For example, the one or more analog devices may perform one or more or all functions while being implemented and / or deployed wholly or partially as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more analog devices may perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device to perform the test, and / or may use air wireless communication to perform the test.

The one or more analog devices may perform one or more functions including all functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device may be used in test scenarios in test laboratories and / or undeployed (eg, tested) wired and / or wireless communication networks to perform tests on one or more components. The one or more simulation devices may be a test device. The analog device may use direct RF coupling and / or wireless communication via RF circuits (which may include one or more antennas as an example) to transmit and / or receive data.

A wide variety of use cases for emerging 5G wireless systems based on general requirements outlined by the International Telecommunication Union-Radio Communications Group (ITU-R), Next Generation Mobile Network (NGMN), and 3rd Generation Partnership Project (3GPP) It can be described as enhanced mobile broadband (eMBB), large machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Different use cases may focus on different requirements, such as higher data rates, higher spectral efficiency, low power and higher energy efficiency, lower latency, and higher reliability. A wide range of frequency bands from 700 million hertz (MHz) to 80 gigahertz (GHz) is considered to be useful in a variety of deployment scenarios.

As the carrier frequency increases, severe path loss may become a significant limitation to ensure adequate coverage. Transmission in millimeter-wave systems may also face non-line-of-sight losses, such as diffraction loss, penetration loss, oxygen absorption loss, leaf surface loss, and so on. During the initial access, the base station and WTRU may need to overcome these high path losses and discover each other. Using dozens or even hundreds of antenna elements to generate a beamforming signal can provide an effective way to compensate for severe path loss by providing significant beamforming gain. Beamforming techniques may include digital beamforming, analog beamforming, and hybrid beamforming.

The cell search may be, for example, a procedure in which the WTRU of one or more of the WTRUs of FIGS. 1A to 1D can acquire time and frequency synchronization with a cell and can detect the cell ID of the cell. The LTE synchronization signal can be transmitted in the 0th and 5th sub-frames of each radio frame and can be used for time and frequency synchronization during initialization. As part of the system acquisition procedure, the WTRU sequentially synchronizes to the orthogonal frequency division multiplexing (OFDM) symbol, time slot, sub-frame, half-frame, and radio frame based on the synchronization signal. The two types of synchronization signals are the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). PSS can be used to get time slot, sub-frame, and half-frame boundaries. It can also provide a physical layer cell identity (PCI) within the cell body group. SSS can be used to get radio frame boundaries. It can also enable the WTRU to determine cell body groupings that can range from 0 to 167.

After successful synchronization and PCI acquisition, the WTRU can decode the physical broadcast channel (PBCH) with the assistance of one or more cell-specific reference signals (CRS) and obtain information about the system bandwidth, system frame number (SFN), and entity mix. MBI information for automatic repeat request (ARQ) indicator channel (PHICH) configuration. In an example, one or more CRSs may be used for channel estimation.

Those skilled in the art can understand that the LTE synchronization signal and the PBCH can be continuously transmitted according to the standard period. For example, one or more of the PSS and SSS may be transmitted continuously.

When the terminal is in RRC_IDLE mode, paging such as LTE paging can be used for network-initiated connection establishment. In LTE, the same mechanism as the downlink data transmission on the downlink shared channel (DL-SCH) can be used and the mobile terminal can monitor L1 / L2 control messaging for the downlink scheduling associated with paging. Since the location of the terminal is usually unknown at the cell level, paging messages are usually transmitted across multiple cells in a so-called tracking area.

An efficient paging procedure should allow the terminal to sleep most of the time without receiver processing and wake up briefly at predefined intervals to monitor paging information from the network. Therefore, a paging cycle can be defined, allowing the terminal to sleep most of the time and only wake up briefly to monitor L1 / L2 control paging. If the terminal detects the group identity used for paging, such as a cyclic redundancy check (CRC) using downlink control information (DCI) using a paging radio network temporary identifier (P-RNTI) (which stands for paging indication) ), When it wakes up, it can process the corresponding downlink paging message transmitted on the paging channel PCH. The paging message may include the identity of the paged terminal, and the terminal that does not find its identity discards the received information and sleeps according to the discontinuous reception (DRX) cycle.

The network can configure the terminal to wake up and listen to the sub-frame targeted for paging. This configuration may be cell-specific (although it may complement the settings of the terminal-specific configuration). Which frame a given terminal should wake up and search for P-RNTI on the physical downlink control channel (PDCCH) can be determined by the equation, which includes (as input) terminal identity and cell-specific and optional Ground terminal specific paging cycle. The range of paging loops for terminals can range from once every 256 frames to once every 32 frames. The sub-frames within a frame to be used for monitoring paging are also obtained from the International Mobile Subscriber Identity (IMSI) linked to the subscription. Since different terminals have different IMSIs, they calculate different paging instances. Therefore, from a network perspective, paging can be transmitted more frequently than once every 32 frames (although not all terminals can be paged at all paging occasions because they are distributed across possible paging instances).

Paging messages can be transmitted only in some sub-frames, ranging from one sub-frame every 32 frames to very high paging capacity with paging in four sub-frames per frame. From a network perspective, the cost of a short paging loop can be minimized because resources not used for paging can be used for ordinary data transmission and not wasted. However, from a terminal perspective, short paging cycles may increase power consumption because the terminal needs to wake up frequently to monitor paging instances.

In addition to initiating a connection to a terminal that is in RRC_IDLE mode, paging can also be used to notify terminals in RRC_IDLE mode and RRC_CONNECTED mode of changes in system information or emergency situations.

In an unlicensed band, a gNB or WTRU may need to perform a pre-talk-to-talk (LBT) procedure before accessing an unlicensed wireless channel. The LBT specifications can be different depending on the regulatory requirements of the unlicensed channel. In general, the LBT procedure may consist of fixed and / or random duration intervals, in which a wireless node (such as a gNB or WTRU) listens to the media, and if it is detected from the media that the energy level is greater than the threshold specified by the regulator, The gNB or WTRU can suppress the transmission of any wireless signal; otherwise the wireless node can transmit its desired signal after completing the LBT procedure.

Under some regulatory regimes, LBT procedures may be mandatory for unlicensed access, and the result is in 3GPP Licensed Assisted Access (LAA) (version 13), Enhanced Licensed Assisted Access (eLAA) (version 14), and License Assistance Access enhancements (feLAA) (version 15) use various LBT types. The LBT Category 4 (CAT4) scheme adopted in LAA / eLAA has been identified as the preferred scheme for most use cases. When the eNB or gNB and in some cases the WTRU wants to transmit control or data in an unlicensed channel, the LBT CAT4 procedure begins. The device then performs an initial headroom assessment (CCA), where the device checks whether the channel is idle for a period of time, which is the sum of a fixed time period and a pseudo-random duration. Channel availability is determined by comparing the energy (ED) level detected across the bandwidth of the unlicensed channel with the energy threshold determined by the regulator.

If the channel is determined to be headroom, transmission is possible. If it is not headroom, the device may perform a time slotted random fallback procedure where random numbers are selected from a specified interval called a contention window. A rollback countdown is obtained and the channel is confirmed to be idle or not, and transmission is initiated when the rollback counter is zero. After the eNB or gNB has obtained access to the channel, it may only be allowed to transmit for a limited duration called the maximum channel occupation time (MCOT). The CAT 4 LBT procedure with random fallback and variable contention window size can be considered to achieve fair channel access and good coexistence with other RATs such as Wi-Fi and other LAA networks.

In licensed assisted non-discrete access, unlicensed band operation can rely on the assistance of the primary component carrier in the licensed band. In the new Radio Unlicensed Band (NR-U) discrete operation, all functions and features should be met for the unlicensed band, including initial access. Initial access is necessary for discrete operations. This article discloses that due to spectrum characteristics and regulatory requirements, such as uncertainty in channel availability, Occupied Channel Bandwidth (OCB) requirements, etc., are designed to enable initial access in licensed bands to be compatible with unlicensed band operation. In some unlicensed frequency bands, such as 5GHz, there may be transmission power spectral density (PSD) limitations. Due to this PSD limitation, power boosting of one or more synchronization signals may not be possible in unlicensed frequency bands and may result in reduced synchronization performance.

For the synchronization signal and the new radio entity broadcast channel (NR-PBCH), the synchronization signal (SS) block appears continuously for each SS burst set for the NR licensed band operation. The maximum transmission bandwidth of the SS block can be 5, 10, 40, and 80 MHz, and the corresponding subcarrier spacing is 15, 30, 120, and 240 kilohertz (kHz). Due to LBT failure, the position of the SS block in the time slot is not optimal for the operation of the NR unlicensed band, which may cause the performance of SS block detection to be degraded. The uncertainty of channel availability also affects the SS burst configuration, such as the period and time window size of the SS burst set. In addition, the OCB requirement is not considered to be the transmission bandwidth for the SS block, but it may be required by the NR-U. Here, SS blocks that meet LBT and OCB requirements are considered to be NR-U.

For paging, the paging loop can be defined to allow the WTRU to monitor paging messages for a predefined number of times. For paging message transmission on unlicensed bands, uncertainty in channel availability may cause paging DCI or paging messages to fail. Therefore, the WTRU may not receive the corresponding paging message. The failure of LBT may also block the timing of paging. This application discloses enhancements to paging that are studied during the NR-U SI and required by the NR-U.

Discovery reference signals (DRS) may need to be integrated with beam-based NR-U. For systems with a large number of beams, effective design may be required. If there is no PDCCH or physical downlink shared channel (PDSCH) for transmission, DRS can occupy a very small bandwidth. Other devices can sense the media and can find that the spectrum width is empty and can transmit. This can cause DRS transmission to fail. For a large number of beams, such as in spectrum use cases above 6 GHz, the total DRS measurement timing configuration (DMTC) duration can be excessively large. Listening before each DRS beam can be used. However, if there is interference, DRS for a specific beam can be skipped. This may introduce increased latency.

According to an example of the disclosed subject matter, this application discloses a multi-level SS / PBCH transmission scheme based on a synchronous signal block (SSB) and an SSB group (SSBG) for NR-U. In NR-U, SS / PBCH transmission can be based on SSBG and SSB structures. As an example, there may be M SSBGs and each SSBG may have N SSBs. For example, M can be eight and N can be eight. For K actual SSB transmissions, M1 SSBG and N1 SSB per SSBG can be used. In order to reduce the impact caused by LBT, such M1 SSBGs can be transmitted continuously. For each LBT, M1 consecutive SSBGs can be transmitted to cover K SSBs. In order to maintain the same SSB mode for each SSBG, N1 consecutive SSBs per SSBG can be transmitted. To avoid gaps between SSBs and reduce waste of resources, all SSBs per SSBG can be used. For example, N1 may be N, for example, N1 may be eight.

As an example, L may be the maximum number of total SSBs per SS burst set (SSBS). L can be 64. If K is large, for example, K is close to or equal to L, the multi-stage method may also include SSBS in the transmission structure.

Multi-level SSBS / SSBG / SSB transmission and channel access can include SSBS level, SSBG level, and SSB level. LBT can be integrated with multi-level structures. For example, a multi-level LBT based on SSBS / SSBG / SSB can be as follows. In one example, Phase 1 may include no LBT at the SSB level. In another example, Phase 1 may include very fast and very short duration LBT at the SSB level. Phase 2 may include fast LBT for SSBG. Phase 3 may include long LBT for SSBS.

In one example, if the channel occupation time (COT) is less than the predetermined duration (T1), LBT may not be performed for SS / PBCH transmission or very fast LBT may be performed (eg, a very short LBT duration). If COT is greater than the predetermined duration (T1) but less than the second predetermined duration (T2), fast LBT can be performed for SS / PBCH transmission. Otherwise, if the COT is greater than the second predetermined duration (T2), regular or long LBT may be performed for SS / PBCH transmission.

Multi-level beams based on SSBS / SSBG / SSB can be implemented using different beam widths, such as wide beam, medium beam, and narrow beam. For example, a wide beam can be implemented for SSBS, a medium beam can be implemented for SSBG, and a narrow beam can be implemented for SSB.

The channel access indicator (CAI) can be used in the example. In one example, Q-bit CAI can be used in NR-U. For example, Q = 2, a two-bit channel access indicator can be used in NR-U, so CAI for SS / PBCH can be used to specify: 00 for SSBS, 01 for SSBG, 10 for SSB And 11 is reserved for use. The CAI may be included in one or more of the following: PSS, SSS, NR-PBCH, residual minimum system information (RMSI), and the like. For example, if 00 is indicated, the WTRU should expect to receive SSBS, and if 01 is indicated, the WTRU should expect to receive SSBG. In addition, if 10 is indicated, the WTRU should expect to receive an SSB, and if 11 is indicated, the WTRU may discard the indicator, use the indicator for other purposes, or reserve the indicator for possible future use. usage of.

Figure 2 is a diagram showing an example CAI, SSBG indicator, and SSB indicator. As shown in Figure 2, the WTRU may receive CAI 220, SSBG indicator 230, and SSB indicator 240. In one example, the WTRU may receive an indication of SSBG 230 and SSB 240 for actual SSB transmission, for example in RMSI.

FIG. 3 is a diagram showing an exemplary CAI in which the SSBG indicator and the SSB indicator are omitted. In one example, in combination with CAI 320, if 00 is indicated, the WTRU may expect to receive SSBS. The WTRU may discard the indication of SSBG 330 and the indication of SSB 340 for the actual SSB transmission. In one example, correspondingly 16 bits can be released to reduce the burden or can be reused for other purposes to effectively utilize the bits.

FIG. 4 is a diagram showing an exemplary CAI and SSBG indicator in which the SSB indicator is omitted. In one example, if 01 is indicated, the WTRU should expect to receive SSBG. The WTRU may use only the SSBG 420 indication for the actual SSB transmission. In one example, 8 bits can be released to reduce the burden or can be reused for other purposes to effectively utilize the bits. Therefore, the omission of the SSB indicator 440 can be achieved.

In yet another example, if 10 is indicated, the WTRU may expect to receive an SSB. The WTRU may use a joint SSBG and SSB indication for the actual SSB transmission. Therefore, 0 bits can be released to reduce the burden or can be reused for other purposes to effectively utilize the bits. In yet another example, if 11 is indicated, the WTRU may discard the indicator.

According to the examples provided in this application, hierarchical LBT-based SS / PBCH block and SSB group indication techniques are used. CAI and WTRU procedures can be provided so that if 00 is indicated, the WTRU should expect to receive SSBS, which can involve long LBT procedures. In a further example, if 01 is indicated, the WTRU should expect to receive SSBG, which may involve a fast LBT procedure. Furthermore, if 10 is indicated in one example, the WTRU should expect to receive an SSB and each SSB may involve its own LBT procedure. In another example, if 10 is indicated, the WTRU should expect to receive an SSB, which may involve no LBT procedures. In addition, if 11 is indicated in one example, the WTRU may discard the indicator.

In the case of "00", for all SSBG / SSBs in the SSBS, the gNB can execute a single-wide beam LBT procedure, or a multi-directional LBT procedure. If the gNB successfully obtains the channel or spectrum based on the LBT program, the entire SSBS can be transmitted without being interrupted by the next LBT program. For reception of the entire SSBS, "00" may be indicated to the WTRU. Therefore, for the SSB actually transmitted, conventional, such as non-LBT-based SSBG and SSB, can be indicated. In one example, this situation can be referred to as long LBT.

In the case of "01", for SSBS, the gNB may execute a wide-beam LBT procedure or a multi-directional LBT procedure. If the LBT procedure fails, the entire SSBS may not be transmitted without being interrupted by the next LBT procedure. Therefore, for each of the SSBGs in the SSBS, the gNB can also execute separate wide-beam LBT procedures or multi-directional LBT procedures. Only successful SSBGs of the LBT program are transmitted. Therefore, in one example, if the gNB successfully obtains the channel or spectrum based on the LBT procedure for the SSBG, the gNB can transmit the SSBG. The gNB may indicate "01" to the WTRU for SSBG reception. In one example, the SSBG and the SSBG based on the actual transmission of the LBT program and the SSBG based on the actual transmission of the non-LBT program may indicate the SSBG and SSB respectively, and the LBT may be considered for the SSBG of the actual transmission. In one example, this situation is called fast LBT.

In the case of "10", the gNB can perform a wide beam LBT procedure for SSBS, or a multi-directional LBT procedure. If the LBT procedure fails, the gNB can also perform a wide-beam LBT procedure or a multi-directional LBT procedure for the SSBG in the SSBS. Only the SSBGs for which the LBT procedure was successful may be transmitted, in which case all SSBs in the SSBG may be transmitted. However, for an SSBG where the LBT program fails, the gNB can also execute an LBT program for the SSB in the failed SSBG. In this case, some SSBs in which the LBT program in the SSBG succeeded may be transmitted and other SSBs in which the LBT program failed are not transmitted. The WTRU may be indicated "10" for LBT-based SSBG reception and LBT-based SSB reception. The SSBG for the actual transmission based on the LBT program and the SSB for the actual transmission based on the LBT program indicate SSBG and SSB, where LBT is considered for both the SSBG and SSB for the actual transmission. In one example, this situation can be referred to as per SSB LBT.

In another example of the "10" case, the gNB can transmit an SSB without an LBT procedure related to the SSB. The gNB may indicate to the WTRU that the LBT procedure is not performed.

In the case of "11", the gNB can perform wide beam LBT (or multi-directional LBT) for all SSBG / SSBs in the SSBS. If it fails, the entire SSBS may not be transmitted at all.

In one example, for example, the shift indicator may be an N-bit indicator for indicating a 64-bit shift, may be an N1-bit indicator for indicating an 8-shift, and so on, depending on the application. Shift can indicate the time position of the transmission in the time domain and can be expressed in some time units. In one example, the shift may be referred to as a time shift. The shift or time shift may indicate in which time slot the SSB can be transmitted. In another example, the shift or time shift may indicate which OFDM symbol, which SSB candidate position, which minimum time slot, or which non-time slot is transmitted. The granularity level of the shift or time shift can be at the OFDM symbol level, OFDM symbol or M-OFDM symbol group level, where M> 0 and can be predefined, configurable or indicated, SSB level, SSB or M -SSB group level, where M> 0 and can be predefined, configurable or indicated, time slot level, time slot or M time slot group level, where M> 0 and can be predefined, Configurable or indicated, SS burst level, SS burst set level, DRS duration level, and so on. In one example, the transmission may be a downlink transmission. In another example, the transmission may be an on-chain transmission. In yet another example, the transmission may be a side-link transmission, such as a side-link SSB (S-SSB) transmission for V2X. In addition, S-SSB transmissions can be used for licensed and / or unlicensed band communications. This method can also be applied to other signals and / or channels. A shift indicator or a time shift indicator may be received in SS, PBCH, or both. In another example, the shift may indicate a combination of the time units provided above. For example, a shift may indicate in which time slot and in which OFDM symbol a combination of SSBs can be transmitted.

According to an example, in order to indicate the SS block actually transmitted due to LBT, another indicator for the SS block actually transmitted may be used. An SS block indicator, an SSB group indicator, or both can be used. For example, an 8-bit SS block indicator and an 8-bit SSB group indicator may be used for LBT. Such an indicator may be more dynamic than the original indicator because the channel availability is inherently dynamic due to LBT. The WTRU may receive either or both of two sets of indicators: a set with an original SS block indicator and an SSBG indicator, or a set with an LBT-based SS block indicator and an LBT-based SSBG indicator.

FIG. 5 is a diagram showing SSBs and SSBGs updated with examples of dynamic LBT-based SSBs and SSBG indications. The original SS block indicator 530 and the SSBG indicator 520 may be semi-static and may be carried in RMSI, radio resource control (RRC) messaging, and the like. The LBT-based SS block indicator 550 and the LBT-based SSBG indicator 540 can be dynamic and can be controlled by L1 / 2 channels (eg, PDCCH, group common entity downlink control channel (GC-PDCCH), or MAC control information) , Or carried by a MAC Control Element (CE), etc. The LBT-based SS block indicator 550 and SSBG indicator 540 may also be semi-static but have different periods compared to the original SS block indicator 530 and SSBG indicator 520.

The LBT-based SS block indicator 550 and SSBG indicator 540 may replace the original SS block indicator 530 and SSBG indicator 520. In one example, in the original SS block indicator 530 and the SSBG indicator 520, "1" may indicate that an SS block or SSBG is actually transmitted, and "0" may indicate that an SS block or SSBG is not actually transmitted. Similarly, in the LBT-based SS block indicator 550 and SSBG indicator 540, "1" may indicate that the SS block or SSBG is not actually transmitted, and "0" may indicate that the SS block or SSBG is not actually transmitted. When the WTRU receives both the original and LBT-based indicator sets, the WTRU may apply an AND operation to obtain the final set of SS blocks 570 and SSBG 560 that are actually transmitted and updated.

FIG. 6 is a diagram showing a program example of channel access with SSB, SSBG, and SSBS. The WTRU may receive a first set 620 of SSB and SSBG indications. The first set of SSB and SSBG indications may use semi-static messaging. The WTRU may then update SSB and SSBG 630 according to the first set indicated by SSB and SSBG. For example, the WTRU may update the list of SSBs and SSBGs for detection and monitoring at the WTRU. The WTRU may receive a second set 640 of SSB and SSBG indications. The second set of SSB and SSBG instructions can be used for one or more LBT procedures and the instructions can use dynamic messaging. The WTRU may then also update SSB and SSBG650 based on the second set of SSB and SSBG indications. Further, accordingly, the WTRU may use the recently updated SSB and SSBG for monitoring and measurement 660.

FIG. 7A is a diagram showing an example of LBT with channel access of SSB, SSBG, and SSBS. In the example shown in FIG. 7A, hierarchical multi-stage LBT procedures and SSB transmission / reception instructions for NR-U are provided. For example, long LBT procedures can be performed. If the long LBT procedure is successful, all SSBs from time slot 702 to time slot 708 can be transmitted during the SSB scan phase without the need for another LBT program. Therefore, there will be no further interruption of the LBT procedure during the SSB scan phase. In another example shown in FIG. 7A, a fast LBT procedure can be performed. If the fast LBT procedure is successful, all SSBs from time slot 706 to time slot 708 can be transmitted without another LBT program during the SSB group phase. Therefore, there will be no further interruption of the LBT procedure during the SSB group phase. In addition, the SSB indicator can indicate which SSB groups can be transmitted. In yet another example, a fast LBT procedure can be performed and if the fast LBT procedure is successful, all SSBs from time slot 702 to time slot 704 can be transmitted for the SSB group without the need for another LBT program.

In yet another example not shown in Figure 7A, the LBT procedure may be performed for each LBT. For all SSBs from time slot 704 to time slot 708, if the LBT procedure for the SSB is successful, the SSB can be transmitted. Therefore, there can be one LBT program per SSB. In addition, the SSB indicator can indicate which SSBs can be transmitted.

FIG. 7B is a diagram showing another example of LBT with channel access of SSB, SSBG, and SSBS. In the example shown in FIG. 7B, hierarchical multi-stage LBT procedures and SSB transmission / reception instructions are provided for NR-U. As described in this application, a time shift 710 may be indicated to the WTRU. In one example, a long LBT procedure can be performed. If the long LBT program is successful, all SSBs from time slot 720 to time slot 770 can be transmitted without another LBT program during the SSB scan phase. Therefore, there will be no interruption for further LBT procedures during the SSB scan phase as indicated by time period 792. In another example shown in FIG. 7B, a fast LBT procedure can be performed. If the fast LBT procedure is successful, all SSBs from time slot 720 to time slot 740 can be transmitted during the SSB group transmission as indicated by time period 794 without the need for another LBT procedure. In addition, all SSBs from time slot 750 to time slot 770 can be transmitted during the SSB group transmission as indicated by time period 796 without the need for another LBT procedure. Therefore, there will be no interruption to another LBT procedure during the SSB group transmission. In addition, the SSB indicator can indicate which SSB groups can be transmitted.

In a further example shown in Figure 7B, the LBT procedure can be performed for each LBT. For all SSBs from time slot 720 to time slot 770, the SSB can be transmitted if the LBT procedure for the SSB is successful. Therefore, there can be one LBT procedure per SSB during time period 798. In addition, the SSB indicator can indicate which SSBs can be transmitted.

FIG. 8 is a diagram showing an example of LBT using channel access with joint SSB index and time shift. In the example shown in Figure 8, the WTRU can detect the SS / PBCH block 810. The WTRU may then obtain one or more indications 820 about the joint SSB index and time shift from the detected SS / PBCH block. In one example, one or more indications may be obtained from the SS in the detected SS / PBCH block. In another example, one or more indications may be obtained from the PBCH in the detected SS / PBCH block. In addition, the WTRU may derive at least one of frame timing information, time slot timing information, and symbol timing information 830 based on the obtained joint SSB index and time shift. In addition, the WTRU may obtain timing information 840 for detecting CAI, SSB indication, or both. In the event that the WTRU successfully detects one or both of the CAI and SSB indications 850, the WTRU may derive the time position 870 of the SSB based on one or both of the detected CAI and SSB indications. Therefore, the WTRU may perform SSB measurement 880 for the SSB of the actual transmission. In the event that the WTRU fails to detect at least one of the CAI and SSB indications 850, the WTRU may search for and measure all SSBs 860 during the SSB scan. For example, the WTRU may search for all SSB time locations during the SSB scan. The WTRU may also measure all SSBs received during the SSB scan.

In a further example, the CAI may have the status of one LBT procedure for all SSB transmissions during the SSB scan. In another example, the CAI may have the status of one LBT program per SSBG. In addition, there can be interruptions between SSBGs. In another example, the CAI may have the status of one LBT program per SSB. In addition, gNB can perform wide beam LBT procedures for SSBG in SSBS. The gNB may indicate to the WTRU that the procedure is performed.

According to the examples in this disclosure, flexible COT-based SS / PBCH transmission is disclosed. The network can perform LBT procedures before SSB transmission. COT can be based on SSBG to facilitate SSB indication. The network can perform LBT procedures before each SSBG transmission. The WTRU may be provided with an SSBG indication for SSBG transmission. The WTRU may use SSBG indications for at least one of power saving, rate matching, and mobility measurements. The LSB program based on SSBG can achieve low latency SSB acquisition at the cost of consuming additional resources. In order to have more flexible SS / PBCH transmission, COT-based SS / PBCH transmission can be used.

In addition, the network can complete the SSB transmission by the LBT procedure before each SSB transmission. The WTRU may be provided with an SSB indication within each SSBG. If the LBT program of each SSBG shows that the channel is available, the network can execute the LBT program of each SSB in the SSBG.

In one example, if the LBT program for each SSBG shows that the channel is not available, the network can skip the LBT program for each SSB in the SSBG and disable the SSBG in the usage indicator. In another approach, the network may continue the LBT process for each SSB in the SSBG and enable or disable the SSB for the group at an indicator.

If the MCOT can support SSBG or SS burst sets, COT can be used to cover the entire duration of the SSBG or SS burst sets. In addition, COT can be used to cover part of the duration of an SSBG or SS burst set.

Since LBT may have an impact on the actual SSB transmission, under the constraints indicated by the actual SSB, the following scheme can be used. The first solution may include new channel access methods and procedures for SSB transmission in NR-U, and may be introduced to meet the actual SSB transmission requirements and restrictions of NR. The second scheme may include actual SSB transmission requirements and restrictions, and may be modified or enhanced in the NR-U. One or both of the first scheme and the second scheme may be used.

In another example, this application provides SS / PBCH transmission based on a RAT location profile. In order to transmit the SS / PBCH more efficiently, some information obtained from devices of other RATs can be used. Such information may include, but is not limited to, device position, device direction, device beam position, and device beam direction.

The LBT program can be used to obtain some or all of the above information. For example, an LBT procedure may be performed to detect signatures of other RAT devices or detect energy. Other RATs may include, for example, WiFi.

In the first scenario, the gNB can execute the LBT procedure to obtain a profile, and use the profile for SSB instructions. In the example where the LBT procedure is a directional LBT procedure, the LBT procedure may provide beam position profiles for other RATs (such as WiFi).

In one example, different LBT methods can be used individually or in combination. In the first LBT method, only the SSBG level LBT is successful, and the network can execute the SSB level LBT. Otherwise the network can skip the SSBG. This can be compatible with NR. This may result in wasting some resources by skipping some SSBGs. Therefore, some SSBGs may fail in the LBT program but individual SSBs in the failed SSBG may still succeed in the LBT program.

In the second method, even if the SSBG level fails in the LBT process, the network can then execute the SSB level LBT process. If more than X SSBs succeed in the LBT process, the network can turn on the SSBG. Otherwise the network can skip the SSBG. This is compatible with NR. More LBT procedures may need to be performed. Therefore, the SSBG may fail in the LBT procedure but individual SSBs within the failed SSBG may still succeed in the LBT procedure. The parameter X may be predetermined, configured, or indicated. The parameter X can also be obtained from other conditions.

In the third method, if the SSBG level succeeds in LBT, the network can be configured to execute the SSB level LBT procedure according to the SSB mode configuration. Otherwise the network can skip the SSBG. This is compatible with NR. Therefore, more LBT procedures may need to be performed.

The initial LBT for SSBG can be used to determine or preset the SSB mode in the SSBG for the next Y SSBGs in the COT. The parameter Y may be predetermined, configured, or indicated. The parameter Y can also be obtained from other conditions.

According to the example disclosed in this disclosure, this application discloses the SSB indication in NR-U. For NR-U, two types of SSB indications can be introduced: the desired SSB position and the actual SSB position.

The desired SSB position may be the time position where the SSB is to be transmitted. The actual SSB position is the time position where the SSB is actually transmitted. In NR, the desired SSB position is the same as the actual SSB position. In NR-U, due to LBT, the actual SSB position is usually less than the desired SSB position. An indication of the desired SSB position and the actual SSB position may be carried in the RMSI.

RMSI can use the entire candidate SSB instead of the actual SSB for rate matching. Furthermore, since the WTRU typically has not received an SSB indication in the RMSI, it may not use the indication to perform rate matching. However, other DL channels (such as other system information (OSI), paging, random access channel (RACH) Msg2 & 4, PDSCH, etc.) can perform rate matching based on the actual SSB. The subsequent RMSI can also perform rate matching based on the previous actual SSB indication.

The WTRU procedure in the NR may be defined so that if the WTRU receives an actual SSB indication in the RMSI, the WTRU may perform rate matching based on the actual SSB indication. In addition, if the WTRU does not receive an actual SSB indication in the RMSI, the WTRU may perform rate matching based on the entire SSB.

The WTRU procedure in the NR-U may be defined such that if the WTRU receives a desired SSB indication in the RMSI, the WTRU may perform rate matching based on the desired SSB indication. In addition, if the WTRU receives an actual SSB indication in the signal and / or channel, an execution rate matching based on the actual SSB indication may occur. The actual SSB can be based on LBT procedures. In addition, the actual SSB indicates that the desired SSB can be replaced. The actual SSB indication may include information on how to send the actual SSB in the NR-U. In addition, the actual SSB may include example cases of mobile SSB and skipped SSB.

In one example, if the WTRU does not receive the desired SSB or actual SSB indication in the RMSI, performing rate matching based on the entire SSB may occur.

The WTRU procedure in NR and NR-U can be defined so that if the DL channel and SSB conflict or overlap, the WTRU can execute the procedure, and if configured for NR-U, the procedure can be an NR-U procedure. If the WTRU receives a desired SSB indication in the RMSI, the WTRU may perform rate matching based on the desired SSB indication. If the WTRU receives an actual SSB indication in the signal and / or channel, the WTRU may perform rate matching based on the actual SSB indication. The actual SSB can be based on LBT procedures. In addition, the actual SSB indicates that the desired SSB can be replaced. The actual SSB indication may include information on how to send the actual SSB in the NR-U. In addition, the actual SSB may include example cases of moving SSBs or skipping SSBs. If the WTRU does not receive the desired SSB or actual SSB indication in the RMSI, it can perform rate matching based on the entire SSB.

FIG. 9 is a diagram showing an exemplary RMSI that partially conflicts with SSBS. In the example shown in Figure 9, if the DL channel and SSB conflict or overlap, if configured for NR, then the WTRU procedure can be executed. The WTRU procedure may be an NR procedure. If the WTRU receives an actual SSB indication in the RMSI 930, the WTRU may perform rate matching in the SSBS 940 based on the actual SSB indication. In addition, if the WTRU does not receive an actual SSB indication in the RMSI 930, it may perform rate matching based on the entire SSB (eg, SSB 940).

Figure 10 is a diagram of an exemplary RMSI that completely conflicts with SSBS. If the DL channel and SSB do not conflict or overlap, if configured for NR-U, the WTRU procedure can be executed. The WTRU may perform rate matching, and if an indication of the actual SSB is received, the rate matching may be performed based on the desired SSB. In addition, the WTRU may perform rate matching, and if an indication of the actual SSB is received, the rate matching may be based on the actual SSB. Therefore, an indication of the actual SSB replacement and an indication of the desired SSB can be received. For example, an indication may be received in RMSI 1030, 1050 and thus rate matching may be performed for SSBS 1040, 1060.

If the DL channel and SSB do not conflict or overlap, if configured for NR, the WTRU procedure can be executed, and thus the WTRU does not perform rate matching on the SSB. In addition, the WTRU may discard the indication of the actual SSB that was received.

Figure 11 is a diagram showing example LBT, RMSI, and SSBS, where SSBS follows RMSI. In the example shown in Figure 11, LBT 1120 may be performed before RMSI transmission 1130, followed by SSBS transmission 1140. LBT 1120 can be used to determine the actual SSB transmission within SSBS 1140. The LBT 1120 may be used to determine the RMSI transmission 1130, which may indicate to the WTRU the actual SSB transmission within the SSBS 1140.

Figure 12 is a diagram showing example LBT, RMSI, and SSBS, where SSBS may not follow RMSI. In the example shown in FIG. 12, LBT 1220, 1250 may be performed before RMSI transmission 1230, 1260, which may be followed by SSBS transmission 1270 or not after SSBS transmission 1240. LBT 1250 can be used to determine the actual SSB transmission within SSBS 1270. LBT 1220, 1250 can be used to determine RMSI transmissions 1230, 1260, which can indicate the actual SSB transmission within SSBS 1270, which can immediately follow RMSI transmission 1260.

In an example, different periodic and / or time offsets can be applied to SSBS and RMSI. RMSI may or may not have an offset from SSBS.

FIG. 13 is a diagram showing an exemplary RMSI with a larger period than SSBS. In the example shown in Figure 13, when the period of SSBS 1320, 1325, 1340, 1345, 1360, 1365, 1380, 1385 is smaller than RMSI 1310, 1330, 1350, 1370, the actual SSB transmission may not change immediately. Indicated in RMSI.

In an example, an SSBS indication based on an LBT indication may be used. For short SS bursting periods, channel access priority levels can be used, where the entire SSBS duration, for example less than 5 milliseconds (ms), can be reserved after the LBT procedure is successful. An SSBS indicator, such as a bitmap, may be used to indicate the SS bursts within the RMSI period. For the 4 SS bursts in the RMSI cycle, a 4-bit bitmap can be used, whereby 1 can represent the success of the enabled SSBS or LBT program, and 0 can represent the failure of the disabled SSBS or LBT program.

A channel access priority level can be used, where the entire N SS burst duration (NxP) can be reserved after the initial LBT procedure is successful. In the example, N may represent the number of SSBSs in the RMSI period. In addition, P may represent the SS burst period.

In the example, the network can run LBT procedures. Due to successful LBT procedures, the first K SSBs or SSBGs can be reserved.

A combination of disabled SSBs across SSBs during the RMSI cycle can be used. If one SSB is disabled due to LBT program failure, all SSBs in the same location in other SSBGs can be disabled, even if some SSBs in the same location or other SSBGs can be enabled. In the example, the WTRU can buffer the received signal and process the data accordingly.

FIG. 14 is a diagram showing an exemplary RMSI with a cycle shorter than SSBS. In the example shown in Figure 14, the period of SSBS 1420, 1440, 1460, 1480 can be greater than RMSI 1410, 1415, 1430, 1435, 1450, 1455, 1470, 1475. In an example, RMSI can be used to indicate SSB / SSBG / SSBS.

Fig. 15 is a diagram showing an exemplary RMSI having the same period as the SSBS. In the example shown in Figure 15, the periods of SSBS 1520, 1525, 1540, 1545, 1560, 1565, 1580, 1585 can be the same as those of RMSI 1510, 1515, 1530, 1535, 1550, 1555, 1570, 1575. In other examples, the RMSI here can be used to indicate SSB / SSBG / SSBS.

According to an example of the disclosed subject matter, this application discloses a channel access and reservation mechanism for SSB. For example, procedures for channel access for SSB are disclosed. The WTRU may be provided with an indication of the desired SSB transmission. The desired SSB transmission can be indicated in RMSI. LBT can be performed just before SSB transmission, so if LBT is successful, COT is reserved to cover the entire SSBS. This can reduce the number of LBT procedures that must be executed. If the LBT program fails, you can skip the entire SSBS. This may waste the entire SSBS, as some of the SSBG or SSB may still make the LBT procedure successful and may be able to be transmitted. Alternatively, the SSBG LBT program can be executed and if the SSBG LBT program is successful, the entire SSBG can be transmitted. Otherwise you can skip the entire SSBG or SSB LBT procedure and continue. Alternatively, an SSB LBT program may be executed. If the SSB LBT procedure is successful, the SSB can be transmitted, otherwise the SBB can be skipped.

Due to skipping SSB, SSBG, or SSBS, SSB detection performance may be degraded. But resource use can be improved.

The network can reserve channels for the duration of COT transmission of SSB or SSBG. COT can depend on the duration of transmission of SSB or SSBG. Short LBT with short channel reservation duration and long LBT with long channel reservation duration can be supported.

A short LBT with a short channel reservation duration can be used for SSB transmission. Long LBT with long channel reservation duration can be used for SSBG or SSBS transmission. However, a short LBT with a short channel reservation duration and a long LBT with a long channel reservation duration may have relatively low priority channel access.

New channel access priority levels can also be introduced, which can include short LBTs with long channel reservation durations. This can be used to enable SSB transmission in NR-U. Due to the large number of SSBs, a long duration for SSBS transmission may be required. If a short channel reservation duration is used, SSB transmission may be more constrained by channel unavailability and LBT. If long LBT is used, SSB transmission may be blocked. Reducing the duration of the LBT program can increase the chance of accessing the channel. For high-priority channel access, such as SSB transmission, short LBT procedures and long channel reservation durations can be used. Short LBT procedures with long channel reservation duration can be used for SSBG or entire SSBS transmissions with high priority channel access.

If the MCOT cannot support SSBG or the entire SSBS, the COT covers part of the SSBG or part of the SS bursts can be applied, so if the SSBG is partially covered, the SSBG can be disabled and / or the LBT program for each SSB may be Causes the SSBG to be enabled. The RMSI indication may be based on this part of the SSBG for both SSB and SSBG.

To maintain the same number of actual SSB transmissions, the following schemes can be used individually or in combination. In the first scheme, if LBT fails, the base station may repeat or retransmit the SSB at another candidate location. RMSI can indicate this change. This may require additional SSB resources. In the second scheme, the base station can skip the SSB transmission and reduce the number of SSB transmissions. This may cause performance degradation.

During a gap between SSBs or SSBGs, the channel may be reserved for that gap. Some useful DL channels can be transmitted in these gaps instead of dummy signals to avoid wasting resources or improving resource utilization. Useful DL channels are, for example, additional SSB, DRS, PDCCH, PDSCH, RMSI, OSI, RACH Msg2 & 4 and paging.

If the LBT procedure fails, another SSB can be configured, and the network can switch to another SSB location for SSB transmission. The example scheme may use over-provisioning as indicated by the SSB. In preparing the SSB, more than one opportunity may be provided or configured for SSB and / or SSBG transmission. If one SSB or SSBG is skipped due to the LBT program, another SSBS and / or SSBG can be used. In a further example, SSB diversity can be achieved at the cost of additional resources. Rate matching can be based on over-prepared SSB or SSBG instead of actual SSB or SSBG.

Based on the examples of the disclosed subject matter, this application discloses the design and construction of DRS clusters for NR-U, including different DRS designs. Different DRS designs (DRS types) can be used in DRS clusters based on high coverage or low burden. It is also possible to switch between different designs. Consider long and short DRS types. The initial access to the WTRU may use a preset DRS type with a preset / lower period. A DRS type change may be indicated in at least one of RMSI, OSI, or RRC messaging. The SS / PBCH block can be used as the main component of the DRS block. There may or may not be a CRS / channel status information reference signal (CSI-RS), other reference symbols, or other frequency division multiplexing (FDM) physical channels (to complete the DRS).

Short DRS can be a lower burden design. In this design, 4 OFDM symbols can be used to produce a design similar to NR SS / PBCH. One of these designs can be the same as the NR design mapped in 4 OFDM symbols. This can be considered a baseline design, such as PSS, PBCH, SSS, PBCH design. The PBCH symbol can also occupy resource elements (RE) on both sides of the SSS, which is similar to the NR design. The content of the PBCH can be modified according to NR-U requirements and can be applied to all designs disclosed in this application.

In the second example design, wider bandwidth symbols can be used to increase detection capabilities. In the first example, the design may include NRU-PSS, NRU-PBCH, NRU-SSS, NRU-PBCH. NRU-PSS and NRU-SSS can be generated using longer M / Gold sequences (eg, length 255) and NRU-PBCH can have twice the number of REs encoded by lower code rates, for example, for each OFDM symbol Of 24 REs.

In another example, the design may include NRU-PSS, PBCH, NRU-SSS, PBCH. This configuration is similar in design to that described above. However, unlike NR, PBCH can occupy the same number of resource blocks (RBs) as PSS / SSS, which can be 12 RBs.

In NRU, DRS can start anywhere in the DMTC window after the LBT procedure is successful. It can be considered a floating DRS. This can avoid spectrum waste in situations where the frequency spectrum is estimated to be null and when the target DRS time slot or time slot boundaries are not aligned.

In DMTC, DRS can start at any time slot or any symbol in the time slot and can be related to misalignment in the time slot. The example here is related to misalignment for time slots.

To reduce the complexity of the WTRU, different candidate start positions in the time slot can be defined. For example, for a design with 4 OFDM symbols, 2, 4, 6, and 8 candidate start positions within a time slot can be defined.

In an example, a long DRS may be a more burdensome design. It may include SS / PBCH blocks with larger than 4 OFDM symbols. It increases detection probability due to symbol repetition and longer transmission duration. Various designs can be considered, for example according to one design, which can include modified PSS / SSS symbols and repeated PBCH. For example, the design may include NRU-PSS, PBCH, PBCH, NRU-SSS, PBCH, PBCH. Here, NRU-PSS and NRU-SSS can be generated using longer M / Gold sequences. For example, L = 255. Since the number of PBCH symbols is doubled, the total number of REs is also doubled and thus the PBCH can be encoded at a lower coding rate. This can be applied to the following example with multiple PBCH symbols. It may also generate 2 PBCH OFDM symbols and these two symbols are repeated.

In another design example, each symbol of the SS / PBCH block can be repeated twice. For example, the design may include PSS, PSS, PBCH, PBCH, SSS, SSS, PBCH, PBCH. Here, the example cases provided elsewhere in this application provide different candidate start positions possible within the time slot.

In another design paradigm, the PSS / SSS can be repeated twice, and the PBCH can use many more symbols, which can be repeated versions, or use more REs with lower bit rates. For example, the design may include PSS, PSS, PBCH, PBCH, PBCH, SSS, SSS, PBCH, PBCH, PBCH. In addition, example designs may include PSS, PSS, PBCH, PBCH, PBCH, PBCH, SSS, SSS PBCH, PBCH, PBCH, PBCH.

In other designs, the entire block design may be repeated twice. For example, the design can include PSS, PBCH, SSS, PBCH, PSS, PBCH, SSS, PBCH and PSS, PBCH, PBCH, SSS, PBCH, PBCH, PSS, PBCH, PBCH, SSS, PBCH, PBCH. When the number of OFDM symbols is greater than 8, it may not be beneficial to have more than 2 starting candidate positions. However, it is possible to use 2 candidate positions based on this design.

It is possible to use both types, long and short (SS / PBCH block design with a specific choice in the same system), and switch between them. The polarity of PSS / SSS or DMRS of PBCH can be used to indicate long or short type. The WTRU may also be able to use PSS / SSS mode to blindly detect it and detect if a copy is detected.

The wideband SS / PBCH block can be designed to occupy 24 or even 48 RBs for DRS to meet the minimum power requirements. For broadband design, FDM with 2 or more SS / PBCH blocks can be considered. This can be done with long or short designs.

LBT of X µs can be performed before DRS transmission if it does not carry data or if the maximum transmission duration is less than Y ms. Here, according to the proposal, X can be 25 µs for> 6 GHz (based on LAA) and 8 for> 60 GHz. According to the proposal, Y can be 1 ms for> 6 GHz and {0.5, 0.25} ms for> 6 GHz.

In the above exemplary embodiment, different numbers of candidate start positions are used in different designs. This offset in this application may be referred to as a DRS offset (within a time slot). If any predetermined starting point is used for DR, DRS offset can be used to obtain timing information and synchronization signal block time index (SSBI) contained in the PBCH.

The PBCH may carry the position index of the first PSS offset (of the DRS being transmitted). If only one design is used and only two possible candidate positions are used, the polarity of the PSS / SSS or the DRMS of the PBCH can also be used to indicate the DRS offset. If the DRS always starts at a fixed position in the time slot, the DRS offset can be considered to be 0 in the scope of the examples of this application.

According to another design, the SSB position can be used as a reference. These SSB locations can be the same or different from the NR design. Using an offset from the nearest SSB position (SSB offset) and SSBI, the WTRU may be able to obtain timing.

According to the example of the disclosed subject matter, this application discloses the DRS burst design and DMTC window. DRS burst design can be used to take into account beam-based NR design. Due to the possibility of LBT failure, the WTRU may not always receive DRS at time slot 0 or any pre-configured time slot or subframe. A DMTC window can be defined, in which DRS of a DRS cluster can be transmitted at any time slot or any sub-frame in the DMTC window. In the example, in order for the WTRU to accurately obtain the timing for the system, the gNB must indicate the slot offset / subframe offset to the WTRU, as well as the DRS offset mentioned elsewhere in this application. The method of indication may vary and may depend on the type of DRS burst design. DMTC may be defined for different types of burst designs for DRS, which are described below.

Figure 16 is a diagram showing an example DMTC window defined for the entire DRS scan. In the example shown in Figure 16, the DMTC can be defined for the entire scan of the DRS. A long-period DMTC can be defined for all DRS positions as a group. The LBT procedure can be performed before the DRS scan. Due to the initial LBT, DRS can be transmitted on all beams at DRS positions with delay / offset. Subframe offsets, time slot offsets, and DRS offsets in time slots can be indicated in DRS (for example, explicitly in PBCH, implicitly using PBRS's DMRS and SSB, and implicitly using SSS). The LBT procedure may or may not be performed before each DRS transmission. If the LBT procedure is performed for each beam and the channel is found to be busy in a particular beam, the DRS for those beams can be skipped. The second scan can occur within the same DMTC (after updating the sub-frame offset, time slot offset). The SSB list can also be updated for rate matching. Figure 16 illustrates example SSBs 1610 to 1690.

FIG. 17 is a diagram showing an example DMTC window defined for each DRS position. In the example shown in Figure 17, a DMTC window can be defined for each DRS position. The DMTC window can be the same for all locations. However, it can vary with sub-carrier spacing (SCS) or carrier spectrum. DRS burst candidate locations and the actual DRS / SSB transmissions can be used by the WTRU to receive data or perform RRC measurements. The current NR candidate SS / PBCH block may not be able to support transmission of all beams of the DMTC because many candidate positions are adjacent to each other and the DMTC for these positions may overlap. DRS candidate locations must be modified for NR-U to support individual DMTC for each location. For example, one _{DMTC of} T _DMTC ms may be defined for each of the n DRS positions, where n = 1 to 64 for> 6 GHz, and n = 1 to 4 or 8 for> 6 GHz. In addition, T _DMTC can be {0.5mS, 1mS, 2mS}. Figure 17 illustrates example SSBs 1710 and 1720.

Different modes (or T _DMTC values) can be used for different SCS and / or carrier frequencies. The LBT procedure can be performed for each beam. If the channel is found to be busy in the OFDM symbol at the candidate position and the channel headroom is within the defined / configured DMTC window, the DRS can be transmitted using the sub-frame offset, time slot offset, and DRS offset. During the initial access, once the WTRU uses DRS synchronously, it can find the SFN, SSBI, time slot offset, and DRS offset from the PBCH, and obtain the system timing.

FIG. 18 is a diagram showing an example DMTC defined for a beam set. In the example shown in FIG. 18, the DMTC can be defined for the beam set, which can be considered as a hybrid scheme between the above two design examples in FIGS. 16 and 17. Here, a DMTC may be defined for a location set or group. Example SSBs 1810 to 1890 are shown in FIG. Different examples of such burst designs can include the following.

As a first example, a DMTC of T _DMTC ms can be defined for the SSB, with positions {4, 8} + 28 * n and {16, 20} + 28 * n DRS candidate positions. Therefore, different DMTCs can be used for each time slot. They can be located at T ₀ + {4, 8} + T _DMTC * n and T ₀ + {16, 20} + T _DMTC * n, where T ₀ can be the start time of the frame or sub-frame.

As a second example, a T _DMTC ms DMTC can be defined for the SSB, with positions {4, 8, 16, 20} + 28 * n DRS candidate positions (different 2 time slot DMTC groups). The position can also be modified, thereby defining a _{DMTC of} 1 T _DMTC ms for every n candidate positions of {4, 8, 12, 16} + 28 * n, where the positions in each group can be evenly distributed . They can be located at T ₀ + {4, 8, 16, 20} + T _DMTC * n.

As a third example, a _{DMTC of} 1 T _DMTC ms can be defined for the SSB, with positions {8, 12, 16, 20, 32, 36, 40, 44} + 56 * n. (Different DMTC for groups of 4 time slots). They can be located at T ₀ + {8, 12, 16, 20, 32, 36, 40, 44} + T _DMTC * n.

For a given SCS or carrier frequency, the DRS burst mode and DMTC window size can be defined and fixed. The gNB may perform an LBT procedure before transmitting a DRS for each group. The gNB may use larger beams to perform LBT procedures to cover all beam directions used at candidate locations in the group.

If the media is busy during LBT, DRS transmission of all beams at the location of the group may be delayed until the channel is clear. If the channel has headroom within the defined / configured DMTC window, the time slot offset and DRS offset can be used to transmit DRS for the group.

DRS transmission can occur at any point within the DMTC window. The offset may correspond to an actually used sub-frame relative to the original candidate position of the scheduled DRS, and may be designated as a sub-frame offset. The offset of the actually used time slot relative to the time slot of the original candidate position of the scheduled DRS may be specified as the time slot offset. These DRS candidate positions can also be referred to as DMTC timing.

The DRS offset may be an offset of the DRS within the time slot. The gNB can transmit these sub-frame offsets, time slot offsets, and DRS offsets to the WTRU to obtain accurate timing. The sub frame offset / time slot-offset / DRS offset indication can be implicit or explicit, and thus the following examples can be used. The sub-frame offset / time slot offset can be partially or completely included in the NR-PBCH. In addition, the sub-frame offset / time slot offset can also be combined with the DRS offset in the time slot, as discussed in the example described above. In addition, sub frame offset / time slot offset / DRS offset can be combined with SSBI. In addition, the functions of time slot offset / sub frame offset, DRS offset, SSBI, or any combination thereof can be created and indicated. Other possible indication methods may include initialization of a sequence of PBCH-DMRS or SSS. Sequence polarity can also be used to indicate an offset of 1 bit.

Along with initial access, DRS is also used for RRC measurements. In this regard, multiple parameters of the DMTC configuration can be indicated to the WTRU. These parameters can be transmitted in RRC messaging. If multiple DRS configurations are supported, the DRS configuration type can be indicated. If multiple types are supported, there may be a default configuration that is a superset of different configurations, which is used for initial access.

The DMTC duration may be the duration for which the WTRU looks for DRS after the DMTC timing. The DMTC duration may be variable based on the type of DRS configuration, the SCS of the system, or the carrier frequency in which the system is operating. In the example, 6 ms can be used in LAA at> 6GHz. It can also dynamically increase or decrease based on the interference environment.

The DMTC period may be, for example, 40 ms, 80 ms, or 160 ms. The period may also depend on the type of configuration used for DMTC. It may be different for different SCS. The frequency position of the DRS can be indicated if it is different from the preset.

Opportunistic DRS can be transmitted if part of the spectrum of the OFDM symbols transmitted in the DRS cluster is available at a given period. This can mean that for these DRSs, both the DRS offset and the slot offset are zero. The period of opportunistic DRS can be higher than the DMTC window, but due to LBT rules, the transmission of these opportunistic DRS cannot be guaranteed. They may or may not contain RMSI / OSI / paging FDM. The NR-U PBCH may contain a flag to indicate the presence of RMSI / OSI / paging FDM with opportunistic DRS. It is possible to have different frequencies for opportunistic DRS for different beams. The position of the opportunistic DRS in different SSB / beams may be the same as the starting point of the DMTC defined in the example of this application. They can include {4, 8, 16, 20} + 28 * n (for 120kHz SCS) and {8, 12, 16, 20, 32, 36, 40, 44} + 56 * n (for 240kHz SCS).

According to the example of the disclosed subject matter, RMSI transmission in NR-U is disclosed. SS blocks with 60 kHz SCS and multiplexed SSB / RMSI can be used. FDM can be used for 30kHz SCS and TDM can be used for 60kHz SCS. This configuration may be suitable for SSBs that meet OCB requirements. The presence or absence of RMSI can be indicated in the PBCH. SS / PBCH block repetition and / or CSI-RS can be used as reserved signals.

RMSI can perform time or frequency multiplexing with SS / PBCH in NR-U. During the cell search, if the WTRU determines that there is a RMSI control resource set (CORESET), the WTRU may use the indicator bit in the PBCH to determine the timing and frequency resources of the RMSI CORESET. These bits can indicate SFN and slot index. The SFN and time slot index may be relative to the NR-U SS / PBCH block or may be absolute based on timing information obtained from the SS / PBCH block. It may depend on whether the subcarrier spacing of the SS / PBCH and RMSI is the same or different.

SS / PBCH and RMSI can be TDM. Individual LBTs for RMSI PDCCH may be required. The LBT procedure may fail and the gNB may not transmit the RMSI PDCCH at the determined time slot / location. Therefore, a window for RMSI CORESET can be defined and the start position of the window can be indicated, for example, in SSB or PBCH. The length of the window used for RMSI reception can also be indicated. Within this RMSI reception window, there may be RMSI CORESET. This window can be defined in terms of the number of time slots or OFDM symbols, for example as X time slots or OFDM symbols. The example window length may also be constant, predetermined, or known to the WTRU. In order to indicate the time information (for example, SFN, time slot) with a small number of bits, frequency information (for example, start / offset, number of RBs), and duration (for example, in terms of time slots or symbols) Use multiple tables. These tables can be selected based on system parameters (for example, SCS, operating band, etc.). Different indexes of the table can indicate a set of predefined values. The symbol index in the time slot may or may not be used to indicate the start symbol of CORESET. If a symbol is specified, the WTRU may monitor a specific symbol for CORESET in each of the X time slots. If no symbol index is specified, the WTRU may monitor all CORESETs in each of the X time slots.

As an example, TDM multiplexed SS / PBCH blocks and CORESET can be used. The WTRU may monitor the PDCCH in RMSI CORESET at X consecutive time slots starting from time slot n ₀ . For the SS / PBCH block with index i , the WTRU may determine the index of time slot n ₀ as . Can be based on Whether the SFN is odd or even. M , O , timeslot number, and X can be provided by a table, which can be known to gNB and WTRU.

As another example, FDM can be used to multiplex SS / PBCH blocks and RMSI CORESET. The WTRU may monitor the PDCCH in the RMSI CORESET using the period of the SS / PBCH block or an integer multiple of the SS / PBCH block. In these cases, the WTRU may determine the timing slot indexes n _c and SFN _c based on the parameters from the table and the SCS. The WTRU may also use the operating band of the SS / PBCH block with index i .

According to the example of the disclosed subject matter, when transmitting DRS on multiple BWPs, gNB can perform the following procedures. For example, a first multiple BWP access procedure can be configured, so that during a DMTC cycle, the gNB can perform channel access on each BWP individually at all BWP DRSs that need to be transmitted. The gNB can transmit at all BWP headroom energy transmissions. After the LBT procedure, if the gNB finds that some BWPs are empty and others are busy, the gNB can transmit reserved signals on the BWPs that will be available. If a busy BWP becomes available within the DMRC, the gNB can transmit DRS on all BWPs simultaneously. It can include the same DRS offset and time slot offset in the DRS transmitted on all BWPs.

A second multiple BWP access procedure can be configured so that the gNB can execute the LBT procedure on the main BWP. If the main BWP is found to be empty, the gNB can transmit simultaneously on all BWPs so it transmits the same OSI / RMSI on all BWPs and / or different redundant versions of OSI / RMSI (RV ).

A third multiple BWP access procedure can be configured so that during a DMTC cycle, the gNB can perform channel access on each BWP individually at all BWP DRSs that need to be transmitted. The gNB can transmit DRS on the BWP when the BWP becomes available. For example, after the LBT procedure, if gNB finds that some BWPs will be empty and others are busy, gNB can transmit DRS on the available BWPs. If a busy BWP becomes available within the DMTC, the gNB can also transmit DRS on these BWPs. It can include different DRS offsets and time slot offsets in different BWPs based on the DRS position.

To align DRS in different BWPs, different paradigm rules can be used. For example, a different DMTC may be used for each BWP, DMTC may only be used for cell-defined SSBs, and / or non-cell-defined SSBs may be used only for opportunistic DRS.

According to the example disclosed in this application, in NR-U, the gNB can perform the LBT procedure before transmitting the paging DCI and the paging message. If the channel is not completely clear at the paging occasion, LBT may fail. Therefore, a window can be specified during which the WTRU can continue to observe DCI for the P-RNTI. The gNB can execute the LBT procedure and transmit the paging DCI at any time during the Paging Opportunity Window (PWO). The paging DCI can indicate the location of the paging message.

If the paging message is transmitted in a time slot (or non-time slot) after paging DCI, the next time slot can be reserved by using the time slot configuration indicator (or non-time slot configuration indicator). In NR-U, the frame structure 3 (FS3) defined for LAA can be modified, so gNB can start with any OFDM symbol (or non-time slot). The gNB may include a time slot configuration indicator in a PDCCH (on a common search space) of the time slot. The time slot (or non-time slot) format indicator can indicate the number of OFDM symbols and the transmission direction of the current or next time slot (or mini time slot).

In NR-U, COT can be defined for each LBT category and SCS. If it is possible to transmit paging DCI and paging messages within one COT duration, gNB may have to perform only one LBT procedure. CAT2 (no fallback) / CAT4-P1 (small fallback) LBT can be used for paging transmission.

COT is 1 ms for CAT2 LBT and 2 ms for CAT4-P1 (defined for> 6GHz in LAA). For carriers> 6GHz, COT can be modified to a smaller number. It may or may not always be possible to place the paging message in the same time slot or mini time slot as the paging DCI, and thus this requirement may or may not be met.

It is also possible to use two separate LBT programs. Specifically, if the paging message is scheduled in a later time slot, which exceeds the acquired COT boundary, the first LBT program can be used to page DCI and the second LBT program can be used to page the message. The example disclosed above can be applied to each beam where the paging DCI and paging messages are transmitted.

According to the example of the disclosed subject matter, an NR paging occasion window (NR-PWO) for NR-U can be defined by some continuous sub-frames or mini-slot time slots, where the new radio entity addressing the paging message The P-RNTI is transmitted on a chain control channel (NR-PDCCH). NR-PWO can start with sub frame # 0 (or have a fixed offset for different beams) and the number of sub frames can be determined by the POW size. One or more of the following NR parameters can be provided in the system information: NR-POW size, Pageless-Slots-To-Monitor, etc. When using DRX, the WTRU only needs to monitor one POW per DRX cycle. Depending on the FDM paged with SS / PBCH or DRS, two example scenarios can be considered.

In the first example scenario, using paging FDM with SS blocks, the NR paging occasion (PO) can be multiplexed with DRS, which means that POW can overlap with DMTC. POW can be defined as the entire duration of the DMTC, where the PDCCH of the addressed paging message exists in any time slot / mini time slot. In such a scenario, the POW size can be the same or lower than the DMTC window size. The WTRU can observe the PO for the paging DCI for the entire POW size. After it receives a certain number of time slots without P-RNTI (no paging time slot to monitor), it may stop observing PO for paging DCI. If the period of the DMTC in the system NR-U is X and the number of paging groups based on the IMSI that needs to be supported is Y, the period of each PO becomes a lower factor Y. In NR-U, in order to increase the period of each PO, it is also possible to divide and multiplex multiple messages from different groups. The LBT procedure performed for the SS / PBCH block can be used for POs of multiple groups. To achieve this, a DCI with a P-RNTI may also indicate a group that may be the target of a paging message. Different groups based on IMSI may be able to find their paging messages based on a predefined time-frequency pattern.

In the second example scenario, NR-POW may not be compatible with DRS / SSBFDM. In such a scenario, the NR-POW may be defined (or associated with) each beam (corresponding to each DRS / SSB). POW can be defined as X number of consecutive time slots / mini time slots, where P-RNTI can be transmitted on the PDCCH of the addressed paging message. The paging DCI for NR-POW can be located in a common search space. Paging messages can be in the same time slot (or non-time slot). It can also be located in the rear slot or mini slot.

Due to the characteristics of the NR-U system, there may be problems when the gNB transmits P-DCI after the LBT procedure but the WTRU does not hear it due to interference with hidden nodes. In this case, the gNB can transmit the paging DCI again at the next PO. However, this method adds latency. The gNB may also be able to increase or decrease the period of the PO based on the interference environment. The modification of the PO period can be indicated to the WTRU through RRC signaling.

If the paging DCI or paging message is fully transmitted before the end of the POW duration, the gNB may be able to indicate the end of the POW. The gNB slot configuration indicator or slot format indicator for paging is used to indicate the number of symbols that the paging DCI and paging message can occupy. The time slot configuration indicator may be similar to the sub frame configuration indicator (for frame structure type 3) defined for LAA, which may indicate the total number of OFDM symbols to be transmitted for the current or subsequent time slot. The WTRU may stop monitoring the PDCCH before the end of the POW, if it detects that there is no P-RNTI-assigned service cell transmission in the PDCCH in the number of consecutive time slots to be monitored in the no paging time slot. It is possible to transmit to the WTRU through higher level messaging to transmit no paging slots to be monitored. It is also possible to define no paging non-slots to be monitored for similar purposes.

In the example, POWs can be defined for multiple paging groups and paging subgroups. IMSI-based different POWs for different beams and different groups can start at different time slots and system frames. Different RBs can be used for different paging subgroups. For example, different but fixed RB positions can be defined for paging subgroups. POWs for different subgroups can be FDM together. In addition, having repeated frequency hops, fixed patterns of frequency hops, and frequency hops between groups during the POW can reduce the probability of interference by hidden nodes. In an alternative design, all groups can be scheduled in FDM and an indicator bitmap about the paged group can be used in DCI.

According to the example of the disclosed subject, the paging occasion window calculation is disclosed, for example, PF_B = SFN mod T == (T div N_b) * (WTRU_ID mod N_b) can be used to calculate PF for each beam (PF_B). PO can be calculated from i_s = floor (WTRU_ID / N_b) mod Ns_b. Ns_b, N_b will be modified for the number of beams (maximum or actual use), and nB: 4T, 2T, T, T / 2, T / 4, T / 8, T / 16, T / 32, T / 64,… T / 256… etc .; N_b: min (T, nB) * numBeams; and Ns_b: max (1, nB / T) * numBeams.

The POW size may depend on one or more factors (eg, if there are STAs / WTRUs for other RATs). For example, if there are no WTRUs or other service providers for other RATs, a 1-slot (or non-slot) POW may be sufficient. Another factor can be the network load, whereby a small POW size can be used for low network loads, as the media can be controlled by gNB. Another factor may be that the unit of the POW size may be a time slot of a mini time slot or a mini time slot of a different length, which may be preset for paging. Another factor may be that the POW size can be indicated in RMSI / RRC messaging. The POW can start at the same position as the PO calculated for the NR and last the duration of the POW size.

According to the example of the disclosed subject matter, alternative techniques for paging for NR-U are disclosed, whereby for example paging can be transmitted in the initial active BWP. A paging frame (PF) may be a radio frame, which may include a POW (if a P-RNTI is transmitted on the PDCCH). The first radio frame of the POW may contain repetitions.

When using DRX, the WTRU may only need to monitor the POW every DRX cycle. If a paging indication is used, the PDCCH in the POW is monitored only if the paging indication indicates a WTRU group. A WTRU group can be derived from a WTRU ID. PF can be provided based on the following equation:
SFN mod T = (T div N + PF_Offset) * (WTRU_ID mod N) Equation (1).

Some multiplexing modes between CORESET and SS / PBCH blocks for paging can be used in NR-U. TDM can be used, and therefore paging can appear in subsequent frames. FDM can be used for the current SS / PBCH block. For TDM, POW can start at slot # 0 of the frame and the number of sub-frames can be determined by the POW size. For FDM, POW can start at slot # 0 and the number of sub-frames can be determined by the POW size. The WTRU may stop monitoring the PDCCH before the POW ends if it detects that there are no serving cell transmissions allocated by the P-RNTI in the PDCCH without the number of consecutive sub-frames to be monitored by the paging sub-frame. The no-paging sub-frame shall be monitored and signaled during RRC messaging.

To reduce power consumption, some physical layer paging instructions can be used for paging. This may be a specific signal, which may indicate an upcoming paging for a specific group. A wake-up signal (WUS) can be used to indicate a specific group. WUS cyclic shift or different versions of WUS can be used. You can also use WUS functions. WUS can be transmitted on all beams as part of the SS / PBCH block. Can use advanced paging. This can reduce WTRU complexity. The WTRU may monitor the paging PDCCH only if the paging indicator for its group is present or the WUS indicates that the group is present. The paging indicator or WUS may be located at an offset before the SS block or may be part of the SS block. Cyclic shift or orthogonal cover code (OCC) can be used for this indication.

FIG. 19 is a flowchart showing an example paging method using beam feedback. In the example shown in Figure 19, the WTRU may receive a beam scan paging group indicator 1920. The WTRU may determine whether its group is paged 1930 based on the paging group indicator of the received beam scan. WTRUs in the indicated group may transmit beam feedback 1940 to the base station. Specifically, the WTRU and other WTRUs in the indicated group may perform beam reporting 1950 with limited or full beam feedback. The WTRU can check the current procedure and can enhance the procedure during beam reporting. Because of the beam feedback, the base station can transmit in the selected beam direction and the WTRU can receive PDCCH, PDSCH, or both.

Figure 20 is a flowchart showing another example method for paging. In the example shown in Figure 20, the WTRU may receive a beam scanning paging group indicator 2020. The WTRU may determine whether its group is paged 2030 based on the paging group indicator of the received beam scan. If the WTRU's group is not paged, the WTRU may not attempt and decode the paging PDCCH or paging PDSCH. This may lead to time savings. In addition, if the group of WTRUs is paged, the WTRU may try and decode the paging PDCCH, the paging PDSCH, or both.

In a further example, a method combining a solution provided by the present application or a combination of hybrid methods may be used. For example, the paging method example of FIG. 19 and the example of FIG. 20 can be combined into a hybrid paging method.

Power saving mechanisms can be used for paging and PO for NR-U. The wake-up signal can be used for NR-U. LBT can be performed in conjunction with WUS. The scheme for paging based on the wake-up signal may use an NR-PSS-type structure, a WiFi-type structure, or a hybrid structure. A repeating structure similar to the old long training field (L-LTF) in WiFi can be used. You can add 3 different M / Gold sequences in front of the SS / PBCH block, such as the discovery symbol before PSS / SSS. M / Gold sequences with WTRU / group-specific shifts can be used for WUS-based paging and other PDCCHs. In addition, a group-based PDCCH WUS can be used.

The wake-up signal can be configured in the initial active BWP. A time repeating (zeroed subcarrier) structure similar to L-LTF in WiFi with 3 different M / Gold sequences can be added in front of the SS / PBCH block. Packets for WUS in NR-U can be used, such as WTRU-ID based. Prefaces with or without NAV UL / DL indicators can be used. This can also be used for multi-cell or multi-TRP operations. For NR-U, RMSI monitoring can be performed. For multiple subgroups, multiple WUSs can be tone interleaved or multiplexed. A WTRU ID based offset can be used. WUS can be used for FBE structures because it can be aligned with one or more frame boundaries. Can use UL and DL WUS. The UL WUS may indicate to other WTRUs the acquired COT and planned transmissions. WUS with different cyclic shifts (or OCCs) may indicate a quantized load duration that will be transmitted subsequently. For example, DL / UL may be indicated by a simple reverse sequence X / -X sequence. WUS can enable the WTRU to detect signals (such as SSS) before entering the actual demodulation PDCCH (such as for paging DCI).

In unlicensed operation, due to LBT, it may not be guaranteed that the gNB can send the PDCCH to the corresponding WTRU during the configured PDCCH monitoring timing. If the PDCCH monitoring timing is increased by reducing the period, it may result in more frequent attempts to decode the PDCCH and may potentially increase the power consumption of the WTRU. Unlicensed NR for paging or other DL channels may consider WUS. Simple correlation blocks can be used to perform special sequence detection. If the WUS is not detected, or is detected but indicates an idle mode, the WTRU goes back to sleep without being disturbed by decoding the PDCCH. Otherwise, the WTRU may wake up and may perform PDCCH decoding, for example, for the paging PDCCH.

WUS can be used for paging or other DL signals or channels. A modified version of SSS (or PSS) with group signature can be used. Orthogonal sequences in the frequency domain (such as Zadoff-Chu (ZC) -like sequences) can be used. It or they can span multiple OFDM symbols but is not desirable from a power consumption perspective. Two (or more) levels of WUS can be used. For example, the first level may be a cell-specific WUS (with synchronization function) and the second level may be a PO-specific WUS. Group-based or subgroup-based WUS can also be used. ZC sequences with PN sequence cover codes can be used for WUS. Both time and frequency domains can be considered. The PN sequence or code can be an M sequence or a Gold sequence. An on / off key (OOK) based tone signal can be used. Consider non-coherent energy detection. Design parameters may be considered, such as the number of tones, the number of guard tones, and / or the number of OFDM symbols. Preferably, from a power saving perspective, it is better not to spread over multiple symbols. Time / frequency diversity can be achieved using time / frequency IF mode. Transmission diversity can be used for WUS. The WUS length can be one (or more) time slots, mini time slots, multiple time slots, or one or more OFDM symbols. Variable WUS length can be used. A simplified PDCCH may be used, where baseband processing is substantially downsampled to allow lighter versions of receiver processing. WUS-based paging indication can be used for NR-U. The wake-up signal and the actual PDCCH with paging DCI can be in the same time slot or different time slots (cross time slots). The LBT procedure can be performed for the wake-up signal and the LBT procedure can be performed for the actual PDCCH. In addition, in NR-U, a packet for WUS can be used. A preamble that potentially has a NAV UL / DL indicator, such as for a multi-cell design, can be used. NAV can be used in UL. If only the gNB sends a NAV indication, it may not be possible to completely avoid hidden nodes. Consider and use prefaces that implement asynchronous detection.

According to an example of the disclosed subject matter, a channel access and reservation mechanism for paging is disclosed, whereby for NR-U, for example, an LBT procedure can be performed before transmitting a PDCCH with paging DCI and potentially paging messages. Since paging is transmitted in a multi-beam direction, different listening and transmission combinations for LBT can be considered, such as omnidirectional listening directional transmission and directional listening and directional transmission.

In omnidirectional listening directional transmission, since directional transmission can have a longer range, gNB can change the sensitivity of omnidirectional listening. As another option, it can perform a single LBT procedure in all directions before transmitting the paging DCI. The gNB can perform CAT4-priority 1 omnidirectional LBT to achieve a longer COT to transmit in multiple beam directions. According to this design, all beams can be part of the same POW (grouped by WTRU_ID only). According to different designs, gNB can perform LBT before each directional transmission to avoid interference / collision issues for ongoing transmissions.

In directional listening and directional transmission, gNB can perform directional LBT in each direction before transmission. CAT2 can be used (25us listening for> 6GHz, no fallback), because it can be less than 1ms for> 6GHz transmission. Here, each LBT procedure may be part of a POW for a particular direction. This example approach also avoids exposed node issues.

If paging DCI and / or paging messages are FDM with DRS, POW can overlap with the DMTC window, and thus the LBT procedure performed for DRS can be sufficient to transmit cyclic DCI and potentially paging messages. The LBT parameters used for NR-U paging may be different from the conventional NR-U LBT parameters. Therefore, in the example, the LBT parameters can be modified for directional listening.

According to the example of the disclosure theme, non-time slot-based paging and cross-time slot scheduling are disclosed. In a time slot or non-time slot based system, a paging message can be transmitted in a time slot or non-time slot different from the time slot or non-time slot in which the DCI is paged. In such a configuration, a situation occurs if the NR-U gNB can send a paging DCI (P-DCI) after LBT. However, gNB does not send a paging message (PM) in the time / frequency (T / F) location due to the LBT procedure failure (missing transmission). It is also possible that gNB can send PM at the (T / F) position within the COT, but the reception fails due to hidden node interference.

Rules can be generated to address this issue, whereby the gNB must schedule paging messages within the acquired OCT during paging DCI. It is mandatory for gNB to use the same time slot or (non-time slot). It can be a continuous time slot or a non-time slot, which can be reserved by a time slot configuration indicator. It is also possible to define windows for receiving paging messages in a time slot schedule. If such a window is defined, the WTRU may continue to observe longer duration or more T / F resources for the paging message after receiving the paging DCI.

According to the example of the disclosed subject matter, in NR-U, a bidirectional time slot structure can be used for advanced paging. An immediate response from the paged WTRU in the same beam can be used.

Fig. 21 is a diagram showing an example of paging in a two-way time slot. As shown in the example in FIG. 21, the gNB can transmit a paging group indicator and a paging DCI 2120. After the handover gap 2130, the particular PO and all WTRUs in the paging group may send a response in the next OFDM symbol. Users in these groups can be assigned RBs and / or codes to be used for paging responses. This can also include feedback. It can also carry optional small control / data upload / HARQ transmission. Depending on the feedback received, the paging message 2150 may or may not be transmitted, otherwise the rest of the time slot may be used for other materials. If no other data is to be transmitted, the slot configuration indicator can be used to release the media.

Although the features and elements are described above in specific combinations, those skilled in the art can understand that each feature or element can be used alone or in combination with other features and elements. Although the scheme described in this application can consider LTE, LTE-A, new radio (NR) or 5G specific protocols, it can be understood that the scheme described in this application is not limited to this scenario and other wireless systems can also be applied.

In addition, the methods described herein may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted over wired and / 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), scratchpads, cache memory, semiconductor memory devices, magnetic media such as internal hard drives, and Removable magnetic disks), magneto-optical media and / or optical media (such as CD-ROM discs and / or digital versatile discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver for use in WTRU, UE, terminal, base station, RNC, and / or any host computer.

100‧‧‧communication system

102, 102a, 102b, 102c, 102d ‧‧‧ Wireless Transmit / Receive Unit (WTRU)

104, 113‧‧‧ Radio Access Network (RAN)

106, 115‧‧‧ Core Network (CN)

108‧‧‧ Public Switched Telephone Network (PSTN)

110‧‧‧Internet

112‧‧‧Other networks

114a, 114b‧‧‧ base station

116‧‧‧ air interface

118‧‧‧Processor

120‧‧‧ Transceiver

122‧‧‧Transmit / Receive Element

124‧‧‧Speaker / Microphone

126‧‧‧Keyboard

128‧‧‧Display / Touchpad

130‧‧‧non-removable memory

132‧‧‧ Removable memory

134‧‧‧Power

136‧‧‧Global Positioning System (GPS) Chipset

138‧‧‧Peripheral equipment

160a, 160b, 160c‧‧‧e Node B

162‧‧‧Mobile Management Entity (MME)

164‧‧‧Service Gateway

166‧‧‧Packet Data Network (PDN) Gateway

180a, 180b, 180c‧‧‧gNB

182a, 182b‧‧‧‧Access and mobility management functions (AMF)

183a, 183b‧‧‧ Dialogue Management Function (SMF)

184a, 184b ‧‧‧ User Plane Function (UPF)

185a, 185b‧‧‧ Data Network (DN)

220, 320, 420, CAI‧‧‧ Channel access indicator

230, 330, 430‧‧‧SSBG indicators

240, 340, 440‧‧‧SSB indicators

520‧‧‧original SSBG indicator

530‧‧‧original SS block indicator

540‧‧‧SBTG indicator based on LBT

550‧‧‧LBT-based SS block indicator

560‧‧‧Updated SSBG

570‧‧‧Updated SS

702, 704, 706, 708, 720, 740, 750, 770‧‧‧ hour slots

710‧‧‧time shift

792, 794, 796, 798‧‧‧ time period

930, 1030, 1050, 1130, 1230, 1260, 1310, 1330, 1350, 1370, 1410, 1415, 1430, 1435, 1450, 1455, 1470, 1475, 1510, 1515, 1530, 1535, 1550, 1555, 1570, 1575‧‧‧Remaining Minimum System Information (RMSI)

940, 1040, 1060, 1140, 1270, 1320, 1325, 1340, 1345, 1360, 1365, 1380, 1385, 1420, 1440, 1460, 1480, 1520, 1525, 1540, 1545, 1560, 1565, 1580, 1585‧ ‧SSBS

1120, 1220, 1250, LBT ‧‧‧ listen before conversation

1240‧‧‧SSBS transmission

1610, 1710, 1720, 1810, SSB ‧‧‧ sync signal block

2120‧‧‧ Paging Downlink Control Information (DCI), P-DCI

DMTC‧‧‧ Discovery Reference Signal (DRS) Measurement Timing Configuration

PBCH‧‧‧physical broadcast channel

PDCCH‧‧‧ entity downlink control channel

PDSCH‧‧‧Physical off-chain shared channel

SS / PBCH‧‧‧Sync signal / physical broadcast channel

SSBG‧‧‧SSB Group

PSS / SSS‧‧‧Main sync signal / Second sync signal

WTRU‧‧‧Wireless transmission / reception unit

A more detailed understanding can be obtained from the following description given by way of example with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and in the drawings:

FIG. 1A is a system diagram illustrating an exemplary communication system that can implement one or more of the disclosed embodiments;

FIG. 1B is a system diagram showing an example wireless transmission / reception unit (WTRU) that can be used in the communication system shown in FIG. 1A according to an embodiment; FIG.

FIG. 1C is a system diagram showing an example radio access network (RAN) and an example core network (CN) that can be used in the communication system shown in FIG. 1A according to an embodiment;

FIG. 1D is a system diagram showing another example RAN and another example CN that can be used in a communication system in FIG. 1A according to an embodiment; FIG.

FIG. 2 is a diagram showing an example channel access indicator (CAI), a synchronization signal block group (SSBG) indicator, and a synchronization signal block (SSB) indicator;

FIG. 3 is a diagram showing an exemplary CAI in which the SSBG indicator and the SSB indicator are omitted;

FIG. 4 is a diagram showing an example CAI and SSBG indicator in which the SSB indicator is omitted;

FIG. 5 is a diagram showing the updated SSB and SSBG using an example of SSB and SSBG indication based on dynamic conversation listening (LBT);

FIG. 6 is a flowchart illustrating an example procedure of channel access with SSB, SSBG, and Synchronous Signaling Burst Set (SSBS);

FIG. 7A is a diagram showing an example of LBT with channel access of SSB, SSBG, and SSBS;

FIG. 7B is a diagram showing another example of LBT with channel access of SSB, SSBG, and SSBS;

Figure 8 is a flowchart showing an example of LBT using channel access using joint SSB index and time offset;

FIG. 9 is a diagram showing an example residual minimum system information (RMSI) with partial conflict with SSBS;

FIG. 10 is a diagram showing an exemplary RMSI with complete conflict with SSBS;

FIG. 11 is a diagram showing exemplary LBT, RMSI, and SSBS following SSBS following RMSI;

FIG. 12 is a diagram showing example LBT, RMSI, and SSBS that SSBS may not follow RMSI;

FIG. 13 is a diagram showing an exemplary RMSI with a larger period than SSBS;

FIG. 14 is a diagram showing an exemplary RMSI with a smaller period than SSBS;

Figure 15 is a diagram showing an exemplary RMSI having the same period as the SSBS;

FIG. 16 is a diagram showing an example discovery reference signal (DRS) measurement timing configuration (DMTC) window defined for the entire DRS scan;

Figure 17 is a diagram showing an example DMTC window defined for each DRS position;

FIG. 18 is a diagram showing an example DMTC defined for a beam set;

FIG. 19 is a flowchart showing an example method for paging using beam feedback;

Figure 20 is a flowchart illustrating another example method for paging; and

Fig. 21 is a diagram showing an example of paging in a two-way time slot.

Claims (20)

A method for use in a wireless transmit / receive unit (WTRU), the method comprising: Detect a sync signal (SS) / physical broadcast channel (PBCH) block; Obtaining one or more indications about a joint synchronization signal block (SSB) index and a time shift from the detected SS / PBCH block; Deriving at least one of frame, time slot and symbol timing information based on the obtained joint SSB index and time shift; Obtaining timing information for detecting at least one of a channel access indicator (CAI) or an SSB indication; and Perform SSB measurement. The method as described in claim 1 of the patent application scope, further comprising: In the case where the WTRU successfully detects one or both of the CAI and the SSB indication, one or more of the SSB are derived based on the detected one or both of the CAI and the SSB indication. Time position, where the SSB measurement is performed for the actual transmitted SSB. The method as described in claim 1 of the patent application scope, further comprising: In the case where the WTRU fails to detect at least one of the CAI and the SSB indication, all SSB time positions are searched during an SSB scan, wherein the SSB measurement is for all SSBs received during an SSB scan While being executed. The method as described in item 1 of the patent application scope, wherein the CAI has a state for a pre-talk listen (LBT) procedure for all SSB transmissions during an SSB scan. The method as described in claim 1, wherein the CAI has a state of an LBT program in each SSB group (SSBG). The method as described in claim 5 of the patent application, wherein one of the interruptions is between the SSBGs. The method as described in item 1 of the patent application scope, wherein the CAI has a state of an LBT procedure in each SSB. The method as described in claim 1 of the patent application scope, further comprising: An instruction for a wide beam LBT procedure for SSBG is received in a synchronous signal burst (SSBS). The method as described in item 1 of the patent application scope, wherein one or more indications are obtained from an SS in the detected SS / PBCH block. The method as described in item 1 of the patent application scope, wherein one or more indications can be obtained from a PBCH in the detected SS / PBCH block. A wireless transmit / receive unit (WTRU) including: A transceiver operatively coupled to a processor, the transceiver and the processor being configured to detect a synchronization signal (SS) / physical broadcast channel (PBCH) block; The processor is configured to obtain one or more indications about a joint synchronization signal block (SSB) index and a time shift from the detected SS / PBCH block; The processor is configured to derive at least one of a frame, a time slot, and symbol timing information based on the obtained joint SSB index and time shift; The processor is configured to obtain timing information for at least one of a detection channel access indicator (CAI) or an SSB indication; and The transceiver and the processor are configured to perform SSB measurements. As described in claim 11 of the patent application scope, the WTRU further includes: In the case where the WTRU successfully detects one or both of the CAI and the SSB indication, the processor is configured to derive based on the detected one or both of the CAI and the SSB indication One or more time positions of the SSB, where the SSB measurement is performed for the SSB of the actual transmission. As described in claim 11 of the patent application scope, the WTRU further includes: In the event that the WTRU fails to detect at least one of the CAI and the SSB indication, the transceiver and the processor are configured to search all SSB time locations during an SSB scan, where the SSB measurement is for All SSBs received during an SSB scan are performed. The WTRU according to item 11 of the patent application scope, wherein the CAI has a state for a pre-talk listen (LBT) procedure for all SSB transmissions during an SSB scan. The WTRU according to item 11 of the patent application scope, wherein the CAI has a state of an LBT procedure in each SSB group (SSBG). As described in claim 15 of the patent application scope, one of the interrupts is between the SSBGs. The WTRU according to item 11 of the patent application scope, wherein the CAI has a state of one LBT procedure in each SSB. As described in claim 11 of the patent application scope, the WTRU further includes: The transceiver is configured to receive an indication of a wide beam LBT procedure for SSBG in a synchronous signal burst (SSBS). The WTRU according to item 11 of the patent application scope, wherein one or more indications are obtained from an SS in the detected SS / PBCH block. As described in claim 11 of the patent application scope, one or more indications can be obtained from a PBCH in the detected SS / PBCH block.