Method and apparatus for paging procedures in new radio (NR)

Abstract

To provide methods and apparatuses for paging procedures in wireless systems.SOLUTION: A wireless transmit receive unit (WTRU) may monitor one or more physical downlink control channels (PDCCHs) for paging resources associated with a first subset of synchronization signal (SS) blocks that corresponds to a first beam tracking area (BTA). On a condition that at least one measurement of at least one beam associated with the first subset of SS blocks is less than a predetermined threshold, the WTRU may transmit, to a base station (BS), a signal indicating a second BTA that is associated with a second subset of SS blocks. The signal includes a physical random access channel (PRACH) resource associated with a second group of SS blocks that corresponds to the second BTA.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] This application relates to a method and apparatus for paging procedures in New Radio (NR). [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 519,699, filed June 14, 2017, and U.S. Provisional Patent Application No. 62 / 500,706, filed May 3, 2017, the contents of which are incorporated herein by reference.

[0003] In 5G New Radio (NR), frequency spectrum above 6 GHz has been agreed upon for use to utilize large bandwidths to meet high data rate requirements. One of the challenges in using these frequencies above 6 GHz may be significant propagation loss, especially in outdoor environments, due to higher free-space path loss at higher frequencies. In NR, a beam-centric system is adopted to address the significant path loss at higher frequencies because it can compensate for the path loss without increasing transmit power. For example, multiple beams can be used for initial access and subsequent paging procedures. However, existing paging channels are not designed based on a beam-centric system. Moreover, separate paging channel resources cannot be transmitted with multiple beams in existing paging channels. Therefore, it would be desirable to have a method and apparatus that supports multiplexing of paging messages for multiple wireless transmit / receive units (WTRUs) in a beam-centric system. Summary of the Invention

[0004] Methods and apparatus for paging procedures in a wireless system are described herein. For example, a wireless transmit / receive unit (WTRU) may receive a beam tracking area (BTA) configuration from a base station (BS) that associates a set of synchronization signal (SS) blocks with a respective BTA. The WTRU may select a first SS block in a first subset of SS blocks based on at least one measurement value of at least one beam associated with the set of SS blocks. The WTRU may then identify the first BTA associated with the first subset of SS blocks based on the BTA configuration. The WTRU may then monitor one or more physical downlink control channels (PDCCHs) for paging resources associated with the first subset of SS blocks corresponding to the first BTA. On the condition that at least one measurement value of at least one beam associated with the first subset of SS blocks is below a predetermined threshold, the WTRU may transmit a signal to the base station (BS) indicating a second BTA associated with a second subset of SS blocks. The signal may include a physical random access channel (PRACH) resource associated with a second subset of SS blocks corresponding to the second BTA. The set of SS blocks may include the first subset of SS blocks and the second subset of SS blocks. The SS blocks in the set of SS blocks may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) associated with the SS block. [Brief explanation of the drawings]

[0005] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which:

[0006] [Figure 1A]FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communication system shown in FIG. 1A, according to an embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system shown in FIG. 1A, according to an embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system shown in FIG. 1A, according to an embodiment. [Figure 2A] FIG. 1 illustrates an example of timing for a hyperframe (HF). [Figure 2B] FIG. 10 is a diagram illustrating an example of paging within a hyperframe. [Figure 3] A diagram showing an example of a synchronization signal (SS) block within an SS burst. [Figure 4] FIG. 1 illustrates examples of association types for the New Radio Physical Downlink Control Channel (NR-PDCCH) and the New Radio Physical Downlink Control Channel (NR-PDSCH). [Figure 5] A diagram showing an example of quasi-collocation (QCL) association between SS blocks in an SS burst. [Figure 6] A diagram showing an example of a beam tracking area (BTA) for paging monitoring in an SS burst. [Figure 7] A figure showing another example of BTA for paging monitoring in SS bursts. [Figure 8] FIG. 1 illustrates an exemplary procedure for updating a BTA for paging monitoring. DETAILED DESCRIPTION OF THE INVENTION

[0007] 1A illustrates an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0008] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspot or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0009] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, e.g., the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode-B, a Home Node-B, a Home eNode-B, a gNB, an NR Node-B, a site controller, an access point (AP), a wireless router, etc. While the base stations 114a, 114b are each shown as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0010] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), e.g., a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless services to a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0011] The WTRUs 102a, 102b, 102c, 102d may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the air interface 116, which may be any suitable wireless communications link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0012] More specifically, as described above, the communication system 100 may be a multiple-access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed Downlink (DL) Packet Access (HSDPA) and / or High Speed UL Packet Access (HSUPA).

[0013] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE Advanced (LTE-A) and / or LTE Advanced Pro (LTE-A Pro).

[0014] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0015] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement both LTE and NR radio access, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0016] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology, such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0017] 1A may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. 1A, base station 114b may have a direct connection to the Internet 110. Thus, base station 114b may not be required to access the Internet 110 via CN 106 / 115.

[0018] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, e.g., separate throughput, latency, error tolerance, reliability, data throughput, mobility, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, e.g., user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing Plain Old Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or IP in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0020] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with separate wireless networks over separate wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and with a base station 114b, which may employ an IEEE 802.11 wireless technology.

[0021] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the above elements while remaining consistent with an embodiment.

[0022] 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, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0023] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0024] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0025] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0026] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, for example, on a server or home computer (not shown).

[0027] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0028] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. The WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 in addition to or instead of information from the GPS chipset 136 and / or determine its location based on the timing of signals received from two or more neighboring base stations. It will be appreciated that the WTRU 102 may obtain location information through any suitable location-determination method while remaining consistent with an embodiment.

[0029] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral device 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0030] The WTRU 102 may include a full-duplex radio in which transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference through signal processing in hardware (e.g., a choke) or via a processor (e.g., via a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio in which transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or downlink (e.g., for reception)) may be parallel and / or simultaneous.

[0031] 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As described above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0032] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNode-B 160a may use multiple antennas, for example, to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0033] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0034] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the above elements is shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0035] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a specific serving gateway during initial connection of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0036] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as fixing the user plane during handover between eNode Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0037] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0038] The CN 106 may facilitate communication with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, in certain representative embodiments it is contemplated that such a terminal may be capable of using a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0040] In an exemplary embodiment, the other network 112 may be a WLAN.

[0041] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic to and from the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to the respective destination. Traffic between STAs within a BSS may be sent through the AP, for example, if the source STA can send traffic to the AP, which can deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) a source STA and a destination STA using direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may have no APs, and STAs within or using an IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad hoc" mode of communication.

[0042] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz wide bandwidth) or dynamically configured via signaling. The primary channel may be the operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or identified as busy by a particular STA, the particular STA may back out. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0043] High-throughput (HT) STAs may, for example, use 40 MHz wide channels for communication via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form 40 MHz wide channels.

[0044] A Very High Throughput (VHT) STA may support channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. A 40 MHz channel and / or an 80 MHz channel may be formed by combining adjacent 20 MHz channels. A 160 MHz channel may be formed by combining eight adjacent 20 MHz channels or two non-adjacent 80 MHz channels (which may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel encoding, the data may be passed through a segment parser, which may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped onto two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed and the combined data can be sent to the media access control (MAC).

[0045] Sub-1 GHz modes of operation are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support meter-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices can have limited capabilities, including specific capabilities, such as support for (e.g., only support for) specific and / or limited bandwidths. MTC devices can include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0046] A WLAN system capable of supporting multiple channels and channel bandwidths, e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah, includes a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA supporting the smallest bandwidth operating mode among all STAs operating in the BSS. In the example of 802.11ah, for a STA (e.g., an MTC-type device) that supports (e.g., only supports) the 1 MHz mode, the primary channel may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) setting may depend on the status of the primary channel. If the primary channel is busy, for example due to STAs (that only support a 1 MHz mode of operation) transmitting to the AP, then the entire available frequency band may be considered busy, even though most of those frequency bands may remain idle and available.

[0047] In the United States, the available frequency bands that can be used by 802.11ah are from 902 MHz to 928 MHz. In South Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is from 6 MHz to 26 MHz depending on the country code.

[0048] 1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As described above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0049] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may use multiple antennas, for example, to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multipoint (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0050] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. 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. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including different numbers of OFDM symbols and / or different lengths of absolute time duration).

[0051] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect to a gNB 180a, 180b, 180c while also communicating / connecting to another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may serve as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b may provide coverage and / or throughput to serve the WTRUs 102a, 102b, 102c.

[0052] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0053] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the above elements is shown as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling separate PDU sessions with separate requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service being utilized by the WTRUs 102a, 102b, 102c. For example, separate network slices may be established for separate use cases, such as services relying on Ultra-Reliable Low-Latency (URLLC) access, services relying on enhanced High-Capacity Mobile Broadband (eMBB) access, services related to Machine-Type Communications (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0055] The SMFs 183a and 183b may be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions, such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0056] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0057] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0058] 1A-1D and the corresponding descriptions thereof, one or more or all of the functions described herein in connection with one or more of the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-ab, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0059] The emulation devices may be designed to perform one or more tests of other devices in a lab environment and / or in an operator network environment. For example, one or more emulation devices may perform one or more, or all, functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communications network to test other devices in that communications network. One or more emulation devices may perform one or more, or all, functions while temporarily implemented / deployed as part of a wired and / or wireless communications network. The emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using over-the-air wireless communications.

[0060] The one or more emulation devices may perform one or more functions, including all functions, while not implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing laboratory and / or testing scenario in an undeployed (e.g., testing) wired and / or wireless communication network to perform testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0061] In 5G New Radio (NR), frequency spectrum above 6 GHz has been agreed upon for use to utilize large bandwidths to meet high data rate requirements. One of the challenges in using these frequencies above 6 GHz may be significant propagation loss, especially in outdoor environments, due to the higher free-space path loss at higher frequencies. To address the significant path loss at higher frequencies, beamforming (e.g., analog beams) is employed because it can compensate for the path loss without increasing transmit power. Because beams are used to compensate for path loss, all downlink and uplink channels must be based on beams. Therefore, 5G NR downlink physical channels and downlink control channels must be defined for a beam-based system in which beams are used for the paging channel.

[0062] With regard to paging, a WTRU, for example, in idle mode and / or connected mode, may periodically monitor a physical downlink control channel (PDCCH) for downlink control information (DCI) or downlink (DL) allocations on the PDCCH masked with a paging RNTI (P-RNTI). If the WTRU detects or receives a DCI or DL allocation using the P-RNTI, the WTRU may demodulate an associated or indicated physical downlink shared channel (PDSCH) resource block (RB) and / or decode a paging channel (PCH) that may be carried on the associated or indicated PDSCH. A PDSCH carrying a PCH may be referred to as a PCH PDSCH. As used herein, the terms paging, paging message, or PCH, and variations thereof, may be used interchangeably throughout this disclosure.

[0063] For example, to receive a paging message from the network, a WTRU in idle mode may monitor the PDCCH channel for an RNTI value (i.e., P-RNTI) used to indicate paging. The WTRU may need to monitor the PDCCH channel at specific WTRU-specific occasions (i.e., at specific subframes within specific radio frames). At other times, the WTRU may apply discontinuous reception (DRX), i.e., it may switch off its receiver to conserve battery power. The network may configure which radio frames and subframes are used for paging. Each cell may broadcast a default paging cycle or a WTRU-specific paging cycle. The WTRU may calculate the radio frame (i.e., paging frame) and the subframe within that paging frame (i.e., paging occasion).

[0064] The paging frame (PF) and subframes within that PF (i.e., paging occasions) may be identified based on the WTRU ID (e.g., UE_ID) and parameters that may be specified by the network. These parameters may include, but are not limited to, the paging cycle (PC) length (e.g., in frames) and the number of paging subframes per paging cycle (e.g., nB). The PC length may be the same as the DRX cycle. The number of paging subframes per paging cycle (e.g., nB) may enable identification of the number of PFs per PC (e.g., N) and the number of POs per PF (e.g., Ns) that may be in a cell. The WTRU ID in an embodiment may be the WTRU IMSI mod 1024. The subframes within the PF may be paging occasions (POs) that the WTRU may monitor for a paging channel, e.g., in idle mode.

[0065] From the network perspective, there may be multiple PFs per paging cycle and multiple POs within a PF. For example, multiple subframes per paging cycle may carry a PDCCH masked with a P-RNTI. Additionally, from the WTRU perspective, the WTRU may monitor the PO per paging cycle, and such a PO may be identified based on parameters specified herein (e.g., above). These parameters may be provided to the WTRU via system information, dedicated signaling information, etc. The POs may include pages related to one or more specific WTRUs, or they may include system information change pages that may be directed to each of the WTRUs. In idle mode, the WTRU may receive pages for reasons such as an incoming call or a system information update change.

[0066] In connected mode, the WTRU may receive pages related to, for example, system information changes. The WTRU may not receive WTRU-specific pages that may be used for incoming calls. Thus, a WTRU in connected mode may not monitor a specific PO. Additionally, for frequency division duplexing (FDD), the PO subframes may be limited to specific subframes, such as subframes 0, 4, 5, and 9. For time division duplexing (TDD), the PO subframes may be limited to specific subframes, such as subframes 0, 1, 5, and 6.

[0067] Discontinuous reception (DRX) is described herein. In an idle mode (e.g., RRC idle mode and / or EPS connection management (ECM) idle mode), a WTRU may monitor for or listen for paging messages for incoming calls, system information changes, Earthquake and Tsunami Warning Service (ETWS) notifications for ETWS-enabled WTRUs, Commercial Mobile Alert System (CMAS) notifications, enhanced access restriction parameter modifications, etc.

[0068] The WTRU may discontinuously monitor the PDCCH with respect to the P-RNTI, for example, to reduce battery consumption when there may not be a page for the WTRU. DRX may be or include the process of discontinuously monitoring the PDCCH. In idle mode, DRX may be or include the process of discontinuously monitoring the PDCCH with respect to the P-RNTI, for example, to monitor for or listen for paging messages during RRC idle state.

[0069] As used herein, the terms idle mode, idle state, RRC idle mode, RRC idle state, or RRC_IDLE mode / state may be used interchangeably throughout this disclosure. The terms RRC idle and ECM idle may also be used interchangeably throughout this disclosure. DRX may also be enabled and / or used in connected mode. When in connected mode, if DRX is configured, the MAC entity may discontinuously monitor the PDCCH, for example, using DRX operation. The terms connected mode, connected state, and RRC_CONNECTED mode or state may be used interchangeably. As used herein, the terms paging, paging message, or PCH, and variations thereof, may be used interchangeably throughout this disclosure.

[0070] Idle mode DRX is described herein. The WTRU may use one or more DRX parameters, which may be broadcast, for example, in a system information block (SIB), such as SIB 2, to identify the PF and / or PO to monitor for paging. Alternatively, or additionally, the WTRU may use one or more WTRU-specific DRX cycle parameters, which may be signaled to the WTRU, for example, by signaling from the MME through the NAS.

[0071] Table 1 provides examples of DRX parameters, including example ranges and example sources (e.g., eNB or MME) of the parameters.

[0072] [Table 1]

[0073] The DRX cycle T of the WTRU may indicate the number of radio frames in a paging cycle. A larger value of T may result in less WTRU battery power consumption. A smaller value of T may increase WTRU battery power consumption. The DRX cycle may be cell-specific or WTRU-specific.

[0074] The DRX cycle provided by a base station (BS) (e.g., eNB) may be cell-specific and may be provided to at least some (e.g., all) WTRUs in the cell. The DRX cycle that may be provided by a BS (e.g., eNB) may be a default paging cycle. The DRX cycle provided by an MME may be WTRU-specific. The WTRU may use the smaller of the default paging cycle and the WTRU-specific DRX cycle as its DRX cycle or paging cycle. The MME may provide the WTRU-specific DRX cycle to the WTRU in NAS signaling, for example, as a "WTRU-specific DRX cycle." The MME may provide the WTRU-specific DRX cycle to the BS (e.g., eNB) in a PAGING S1 AP message, for example, as a "Paging DRX" for a paging message initiated by the MME that may be intended for the WTRU.

[0075] The WTRU and / or BS (e.g., eNB) may use the default and minimum for a particular DRX cycle. For example, T=Min(T UE ,-T CELL ). A WTRU with a DRX cycle of N (e.g., 128) radio frames may need to wake up and look for paging messages every N×frame time (e.g., 1.28 seconds for a 10 ms frame time).

[0076] The parameter nB (i.e., the number of paging subframes per paging cycle) may indicate the number of paging occasions in a cell-specific DRX cycle. This parameter may be cell-specific. The configuration of the nB value may depend on the paging capacity that may be desired or used in the cell. A larger value of nB may be used, for example, to increase the paging capacity. A smaller value of nB may be used, for example, for a smaller paging capacity.

[0077] The BS (eg, eNB) and / or the WTRU may calculate the PF of the WTRU according to equation (1) below. PF=SFN mod T=(T div N) * (WTRU_ID mod N) Equation (1) In this case, N is specified as N=min(T,nB). A WTRU-specific PO within a PF may be specified from a set of paging subframes, which may be a function of pre-defined allowed subframes for paging and / or the number of POs per PF, which may be a function of at least nB and / or T. The system frame number (SFN) may have a range of values, such as from 0 to 1023.

[0078] Connected mode DRX is described herein. In connected mode, the PF and PO may be specified in a similar manner as in idle mode. The DRX cycle parameters may be different in idle mode and connected mode. The WTRU may monitor (e.g., any) PO in the PC in connected mode, e.g., to obtain system information change information.

[0079] It may be desirable to have a longer DRX cycle, such as extended DRX (eDRX), for devices such as machine-type communication (MTC) devices. In addition, a longer DRX cycle may be useful for some devices, such as delay-tolerant devices. For example, it may reduce battery consumption and / or increase battery life for those devices.

[0080] FIG. 2A illustrates an example timing 200 for hyperframes (HFs) 205, 210, 215, which may be used in any combination with other embodiments described herein. As illustrated in FIG. 2A , the time units (e.g., hyperframes (HFs) 205, 210, 215) may be used with, as an extension of, or on top of radio frame and / or system frame number (SFN) timing (e.g., legacy SFN timing). One HF 205, 210, 215 may include an SFN cycle 220, e.g., 1024 radio frames or 10.24 seconds. The HF 205, 210, 215 may have a hypersystem frame number (H-SFN). The H-SFN cycle 225 may include 1024 SFN cycles 220. The H-SFN cycle 225 may include 1024 radio frames or 10.24 seconds. * 1024 * It can last for 10 ms (i.e. 174.76 minutes).

[0081] An idle mode extended DRX (I-eDRX) cycle can include up to 256 H-SFN cycles 225. For example, an I-eDRX can include up to 256 H-SFN cycles 225. * 1024 * The H-SFN cycle 225 may last 10 ms (or 43.69 minutes). The H-SFN cycle 225 may be broadcast by the cell. The H-SFN cycle 225 may increment at the SFN cycle boundary.

[0082] 2B shows an example 201 of paging within an HF 205, 210, 215, which may be used in any combination with other embodiments described herein. The H-SFN at which a WTRU may be reachable for paging may be referred to as a paging hyperframe (PH) 235, 240, or the WTRU's PH 235, 240. The PH 235, 240 may be applicable (or only applicable) in ECM idle. The PH 235, 240 may be calculated as a function of the extended DRX cycle and / or the WTRU ID (e.g., IMSI mod(1024)). Within the PH 235, 240, the identification of the PF 250, 255, 260 and / or PO may follow normal DRX rules and / or formulas. For example, the WTRU may receive the PF 250, 255, 260 based on the normal DRX cycle 245. A WTRU's paging window (PW) 265 may be a window or time span corresponding to the set of PFs 250, 255, 260 in the WTRU's PH 235, 240, during which the WTRU may monitor for paging and / or be paged. The PW 265 may include a subset of the available PFs 250, 255, 260 in the PH 235, 240. The PW 265 may be signaled to the WTRU, for example, by the MME in an NAS message. In a PF 250, 255, 260, the WTRU may monitor (or only monitor) one PO. Paging to a WTRU may be repeated in one or more of the WTRU's PFs 250, 255, 260 in that PW 265, for example, if the WTRU does not respond to a previous page.

[0083] A cell's support for idle mode extended DRX (I-eDRX) can be implicitly indicated by broadcasting the H-SFN. For a long DRX cycle, it may be useful for the MME to have some knowledge of when the WTRU will be reachable, e.g., to avoid storing paging requests at the BS (e.g., eNB) for a long time. In connected mode, the DRX cycle can be extended up to the SFN limit, e.g., by extending the range of values for the long DRX cycle to 10.24 seconds.

[0084] FIG. 3 shows an example 300 of synchronization signal (SS) blocks 315, 320, and 325 within an SS burst 305, which may be used in any combination with other embodiments described herein. The synchronization signal burst (SS burst) 305 may be used when multiple beams are used for initial access. For example, the SS burst 305 may be transmitted periodically (e.g., every 20 ms), and each SS burst 305 may include one or more SS blocks 315, 320, and 325. As shown in FIG. 3, one or more SS blocks (i.e., SS block #1 315, SS block #2 320, and SS block #3 325) may be transmitted periodically with a cycle of x ms. Additionally, each of the SS blocks 315, 320, and 325 may be associated with a beam. For example, if 64 beams are used by a base station (BS), there may be 64 SS blocks, with each beam including SS blocks 315, 320, 325 in its respective transmission. In another example, 64 SS blocks may be allocated to one beam.

[0085] As shown in FIG. 3, the SS blocks 315, 320, 325 may include a primary synchronization signal (PSS) 350, a secondary synchronization signal (SSS) 355, and physical broadcast channels (PBCHs) 360, 361, 362. After detecting the synchronization signals (i.e., PSS 350 and SSS 355), the WTRU may decode the PBCHs 360, 361, 362, from which a master information block (MIB) is obtained. The MIB may include several of the most frequently transmitted parameters essential for initial access to a cell. In addition to the MIB, the PBCHs 360, 361, 362 may carry essential information about the SS blocks 315, 320, 325, such as SS block-specific configuration. The SS block-specific configuration may include, but is not limited to, the SS block number, the beam tracking area number associated with the SS block 315, 320, 325, and subsequent control channel configuration (e.g., PDCCH and PDSCH). Based on the SS block-specific configuration, the WTRU may further receive broadcasting signals associated with each SS block 315, 320, 325. For example, the WTRU may receive system information blocks (SIBs) associated with each SS block 315, 320, 325 via the PDSCH.

[0086] As described above, one or more SS blocks 315, 320, 325 in an SS burst 305 may be associated with one or more beams. The number of SS blocks 315, 320, 325 in an SS burst 305 may be specified by the BS (e.g., a gNB) based on the number of beams used at the BS. In an example, if an NB beam is used at the BS (e.g., a gNB), NB SS blocks 315, 320, 325 may be used or transmitted in the SS burst 305. In a single SS burst 305, each SS block 315, 320, 325 may include the same or similar synchronization information for the PSS 350 and SSS 355. However, each SS block 315, 320, 325 may include separate configuration information (e.g., separate SS block numbers) for each PBCH 360, 361, 362 that is specific to the SS block 315, 320, 325 associated with its respective beam.

[0087] As described above, to monitor paging messages, a downlink control channel (e.g., PDCCH or NR-PDCCH) needs to be configured or defined for a WTRU in a beam-based system where beams are used for the paging channel. In one embodiment, the WTRU may monitor the PDCCH or NR-PDCCH for paging messages, and the PDCCH or NR-PDCCH resources and / or search space may be configured, identified, or used in a beam-specific or beam-common manner.

[0088] Beam-specific paging occasions (POs) for the PDCCH or NR-PDCCH in beam-specific systems are described herein. A paging slot may be defined, used, or configured as a slot that can potentially be used for a paging channel in NR. A paging slot may be configured with one or more parameters including at least one of a paging cycle, a cell ID, a numerology (e.g., subcarrier spacing), a slot length (e.g., regular slot or minislot), and a frequency band (e.g., below 6 GHz or above 6 GHz). As used herein, the term paging slot may be used interchangeably with a paging frame, a cell-specific paging slot, and a paging resource throughout this disclosure. A paging slot may include a downlink control channel, such as a PDCCH or NR-PDCCH, for paging monitoring and a downlink shared channel, such as a PDSCH or NR-PDSCH, associated with the paging slot. Specifically, a WTRU may monitor a downlink control channel configured for paging monitoring. When the WTRU receives DCI on the downlink control channel, the DCI may include paging information or scheduling information of a PDSCH, which may carry a paging message. Alternatively, the paging slot may include a PDCCH or NR-PDCCH for paging monitoring only. As used herein, the term PDCCH may be used interchangeably with NR-PDCCH, control resource set (CORESET), search space, search space for paging, common search space, and common search space for paging throughout this disclosure. The term PDSCH may be used interchangeably with NR-PDSCH throughout this disclosure.

[0089] A paging block may be defined, used, or configured as a frequency resource that can potentially be used for a paging channel in NR. A paging block may be one or more frequency resource blocks that can be used for a PDCCH or NR-PDCCH associated with the paging channel. One or more paging blocks may be arranged in a paging slot and configured with one or more parameters including at least one of a cell ID, numerology (e.g., subcarrier spacing), frequency band (e.g., below or above 6 GHz), system bandwidth, number of paging blocks, etc. As used herein, the term paging block may be used interchangeably with paging frequency resource, paging subband, paging narrowband, and paging physical resource block throughout this disclosure.

[0090] Paging resources may be defined, used, or configured along with time (e.g., paging slots) and frequency (e.g., paging block) resources. A paging resource may be referred to as a PDCCH associated with an SS block, or more specifically, a common search space in which the WTRU monitors paging DCI using a P-RNTI.

[0091] A paging occasion (PO) may be defined, used, or configured as a paging resource on which a WTRU may monitor, attempt to decode, or receive DCI associated with a paging channel on the PDCCH or NR-PDCCH. A paging occasion may be considered a paging resource configured or used for a WTRU or a group of WTRUs for paging channel reception. A paging occasion for a WTRU or a group of WTRUs may be a subset of paging resources. The subset of paging resources may be identified, configured, or used based on at least one of a WTRU-specific parameter, a cell-specific parameter, numerology, a frequency band, etc. Examples of WTRU-specific parameters may include, but are not limited to, a WTRU-ID, a DRX cycle, a beam index, a BPL index, and an identified SS block, e.g., an SS block index and an SS block time location during initial access. Examples of cell-specific parameters may include, but are not limited to, a paging resource configuration, a paging slot cycle, etc. Examples of numerology may include, but are not limited to, subcarrier spacing, cyclic prefix length, etc. The frequency band may be below 6 GHz or above 6 GHz. Additionally, one or more paging occasions (POs) may be configured or specified for a WTRU or group of WTRUs, and the WTRU or group of WTRUs may monitor a subset of the POs.

[0092] In one embodiment, a paging slot may be configured or specified in a beam-specific manner by an association between a beam and a PO. For example, a paging slot may be associated with the same beam for an SS block. One or more SS blocks may be used in an SS burst, and each SS block may be associated with a beam or beam pair link (BPL). Each SS block may also be associated with a paging slot that may be dedicated to that SS block. Specifically, the paging slot length may be aligned with the SS block length. For example, N sym If OFDM symbols are used for SS blocks, the paging slot length is N sym It can be an OFDM symbol.

[0093] A paging slot associated with an SS block may be located in the same OFDM symbol used for the associated SS block. Specifically, at least for the PDCCH or NR-PDCCH, the paging slot may be located in the same OFDM symbol that may be used for the SS block. A subset of SS blocks or SS bursts may be used for the paging slot associated with the SS block. For example, if an SS block is transmitted every 20 ms, the paging slot associated with that SS block may be configured as every 20×k ms, where k may be a positive integer. The value of k may be configured by the BS (e.g., gNB). For example, the value of k may be indicated in a broadcasting channel or may be specified based on the number of SS blocks in an SS burst. The value of k may be increased or decreased based on the number of SS blocks in an SS burst, in which case the number of SS blocks in an SS burst may be indicated in a broadcasting signal.

[0094] The subset of SS blocks for a paging slot may be identified from at least one of a cell-specific parameter, a frequency band, a number of OFDM symbols, etc. Specifically, the cell-specific parameters may include at least one of a cell-specific paging cycle, a system bandwidth, a number of paging blocks, a cell ID, etc. The frequency band may be below 6 GHz and / or above 6 GHz. The number of OFDM symbols may be used for the SS block or the PBCH in the SS block.

[0095] The WTRU may assume that a paging resource associated with an SS block may be quasi-colocated (QCL'd) with the SS block (e.g., the PSS, SSS, and / or DM-RS of the PBCH in the SS block). Examples of paging resources associated with an SS block may include, but are not limited to, a demodulation reference signal (DM-RS) of the PDCCH or NR-PDCCH that may be monitored by the WTRU for paging, or a DM-RS of the PDSCH or NR-PDSCH that carries a paging message. Specifically, TX and / or RX beam-related information may be QCL'd between the SS block and its associated paging resource. Furthermore, all QCL parameters (e.g., timing, Doppler spread, delay spread, beam, frequency, etc.) may be assumed to be QCL'd with respect to the SS block and its associated paging resource.

[0096] The paging slot associated with the SS block may be indicated based on time, frequency, and / or offset from the SS block. The PBCH in the SS block may include paging slot location-related information in the MIB, or minimum system information (MSI). For example, the MIB may include a bit field that may carry paging slot-related information. The MSI may include paging slot location-related information. The MSI may be scheduled via a common PDCCH or NR-PDCCH, which may be configured by the MIB. The MSI may be beam-specific. Thus, the MSI may be scheduled by its associated SS block. The common PDCCH or NR-PDCCH for the MSI (or remaining minimum SI (RMSI)) may also be used for the paging channel. The WTRU may monitor the common PDCCH or NR-PDCCH for the MSI (or RMSI) and paging, in which case the DCI for the MSI (or RMSI) and the DCI for paging may be identified by the RNTI. For example, the MSI-RNTI may be used to scramble the CRC of the DCI used for the MSI (or RMSI), and the P-RNTI may be used to scramble the CRC of the DCI used for the paging channel. The DCI sizes for the MSI and paging channel may be the same.

[0097] A time slot for a common NR-PDCCH may be defined, configured, or used based on an SS block. For example, a time slot for a common NR-PDCCH may have the same number of OFDM symbols used for the SS block. A common NR-PDCCH may be associated with an SS block, and a time slot for a common NR-PDCCH associated with the SS block may be located in the same OFDM symbol used for that SS block. A time slot for a common NR-PDCCH may be interchangeably referred to as a paging slot if the common NR-PDCCH may be used for a paging channel. A time slot for a common NR-PDCCH may be interchangeably referred to as a common NR-PDCCH time slot, a slot for a common NR-PDCCH, a common time slot, a beam-specific time slot, and a beam-specific common NR-PDCCH time slot.

[0098] FIG. 4 illustrates example association types 400 for a new radio physical downlink control channel (NR-PDCCH) and a new radio physical downlink control channel (NR-PDSCH) 405, 410, 412, which may be used in any combination with other embodiments described herein. As shown in FIG. 4, one or more association types 405, 410, 412 may be used for the NR-PDCCH and / or the NR-PDSCH for broadcasting and paging channels. For example, a first type (e.g., Type A 405) may use a timeslot for NR-PDCCH 445 and NR-PDSCH 450 transmission. In Type A association 405, the NR-PDCCH 445 associated with SS block #1 415 may be transmitted first in the timeslot. In the next or subsequent timeslot, the NR-PDSCH 450 (or SS block #1 430) associated with the NR-PDCCH 445 may be transmitted with a duration of x ms. The second type (i.e., Type B 410) may use a timeslot for transmission of both the NR-PDCCH 455 and its associated NR-PDSCH 460. In a Type B association 410, the NR-PDCCH 455 and NR-PDSCH 460 associated with SS block #1 415 may be transmitted together in the timeslot. In the next timeslot or subsequent timeslots, the NR-PDCCH 465 and NR-PDSCH 470 associated with SS block #1 430 may be transmitted together. The NR-PDCCH 455 and NR-PDSCH 460 in the first timeslot and the NR-PDCCH 465 and NR-PDSCH 470 in the subsequent timeslots may be considered paging occasions, and each paging occasion may contain the same or different paging information.A third type (i.e., Type C 412) may use the timeslot for the NR-PDCCH 475, while the transmission of its associated NR-PDSCH 480 may be indicated in the DCI of the NR-PDCCH 475. In a Type C association 412, the NR-PDCCH 475 associated with SS block #1 415 may be transmitted first in the timeslot. In the next timeslot or a subsequent timeslot, the NR-PDSCH 480 associated with the NR-PDCCH 475 may be transmitted with a duration of y ms, which may be indicated in the DCI of the NR-PDCCH 475 or may be specified in advance.

[0099] The association types 405, 410, 412 described herein may be identified based on a downlink channel. For example, a first association type (i.e., Type A 405) may be used for an MSI, and a second association type (i.e., Type B 410) may be used for a paging channel. The association types may also be identified based on a frequency band. For example, a first association type (i.e., Type A 405) may be used for a frequency band above 6 GHz, and a second association type (i.e., Type B 410) may be used for a frequency band below 6 GHz.

[0100] For the first type (i.e., Type A 405), the cycle of the timeslot (e.g., x ms) may be specified in advance or configured via a broadcasting signal (e.g., MIB or MSI). For the second type (i.e., Type B 410), the frequency resources allocated to the NR-PDSCH 460, 470 may be indicated in the associated NR-PDCCH 455, 465. For the third type (i.e., Type C 412), the WTRU may monitor the NR-PDCCH 475 in a timeslot that may be aligned with the associated SS block (e.g., SS block #1 415), and the associated NR-PDSCH 480 may be indicated in the DCI of the NR-PDCCH 475. The candidate time offset for the associated NR-PDSCH 480 may be a timeslot that may not overlap with SS blocks 430, 435, 440 (or other SS blocks that may not be associated with the NR-PDCCH).

[0101] In one embodiment, one or more control channel resource sets (CORESETs) may be configured in the paging time resources, and the one or more CORESETs may be located on different frequency resources. A paging frequency resource (e.g., CORESET) of one or more frequency resources (e.g., CORESET) may be used, identified, or configured for a WTRU or group WTRU to monitor for paging messages. The paging frequency resource may be identified based on beam-related information.

[0102] The paging frequency resource may be identified based on the associated SS block. For example, a modulo operation may be used based on the SS block time index and the number of paging frequency resources. Alternatively, or additionally, the paging frequency resource may be identified based on one or more beam indices, which may be provided in the broadcasting signal.

[0103] In another embodiment, a single SS block may be associated with one or more beams, and the number of beams used for a single SS block may be indicated in an associated broadcasting signal. The one or more beams used for an SS block may be referred to as a beam group (or TX beam group). The number of frequency resources and their associated configuration parameters may be transmitted in system information (e.g., remaining minimum system information (RMSI) or other system information (OSI)).

[0104] In another embodiment, the NR-PDCCH resources (e.g., paging resources or DCI) may be common to all SS blocks, and the NR-PDCCH resources may be arranged across multiple SS blocks. The time slot for the associated NR-PDSCH may be indicated in the NR-PDCCH, and the candidate time slot for the associated NR-PDSCH may be based on the beam or BPL used for the NR-PDSCH. The time slot for the associated NR-PDSCH may be indicated with an SS block index. For example, if the NR-PDSCH is transmitted with the beam used for the SS block, the SS block index may be indicated in the NR-PDCCH, and the SS block index may identify the time slot containing the NR-PDSCH.

[0105] In yet another embodiment, NR-PDCCH resources for one or more of Minimum SI (MSI), Other SI (OSI), RACH, and / or paging may be identified based on at least one of a time offset, a frequency offset, a cycle of NR-PDCCH resources, etc. The time offset and frequency offset may be from an associated SS block. The time offset and frequency offset may be indicated in the PBCH in the associated SS block. The cycle of NR-PDCCH resources may be used based on a default cycle (e.g., the cycle of an SS burst, such as 20 ms).

[0106] Beam-common paging occasions are described herein. Paging frames (or paging slots, paging occasions) may be defined, used, or configured in a beam-common manner. Thus, one or more of the POs may be identified or configured for a WTRU regardless of the SS block selected, used, or identified by the WTRU. A paging frame (PF) may be considered or referred to as a cell-specific paging resource. A paging occasion (PO) may be considered or referred to as a paging resource on which a WTRU may monitor or attempt to receive paging messages.

[0107] Time resources for SS bursts may be used or configured for paging frames. SS bursts may include one or more SS blocks and may be transmitted with a duty cycle. Therefore, the number of paging frames available or used in a time window may be determined based on the duty cycle of the SS bursts. For example, if the duty cycle of the SS bursts is shorter, a greater number of paging frames may be used.

[0108] In a paging frame (or paging occasion), downlink control information (DCI), which may be used to schedule the NR-PDSCH carrying paging messages, may be transmitted or received across all beams used for the SS blocks in the SS burst. For example, if N SS blocks are arranged in an SS burst, N control channel resource sets (e.g., CORESET or NR-PDCCH CORESET) may be used or configured, and each CORESET may be associated with an SS block. The WTRU may assume that DCI may be transmitted repeatedly across the N CORESETs, and the same set of NR-PDCCH candidates (or set of control channel elements (CCEs)) may be used for the repeated transmissions of the DCI.

[0109] The subset of NR-PDCCH candidates in each CORESET (e.g., search space, starting CCE index) may be identified as a function of at least one of: (1) one or more cell-specific parameters (e.g., cell ID, frame number, slot number, etc.); (2) one or more SS block-specific parameters (e.g., SS block time index, parameters indicated in the PBCH of the associated SS block); (3) P-RNTI (e.g., RNTI used for paging monitoring); (4) one or more beam-related information (e.g., beam identity index); and (5) RX beam group (e.g., the WTRU may identify a set of Rx beams for paging reception). The RX beam group for paging monitoring may be the most recent RX beam group used before the WTRU went into idle mode. If the RX beam group is changed, the WTRU may update the RX beam group index (e.g., using PRACH resources).

[0110] The WTRU may determine to monitor a subset of the CORESET for paging monitoring. For example, the WTRU may first identify a subset of the CORESET based on measurements of SS blocks before it starts monitoring or attempting paging reception. The WTRU may then attempt to monitor or receive paging messages within the identified subset of the CORESET. The DM-RS of each CORESET may be QCL'd with the SSS and / or DM-RS of the PBCH of the associated SS block.

[0111] In one embodiment, a DCI for scheduling the NR-PDSCH carrying a paging message may be used for a direct indication related to a system information update. Specifically, a flag bit in the DCI may be used to indicate whether the DCI carries NR-PDSCH scheduling information or direct indication-related information. If the flag bit is set to “true,” the remaining DCI bits may be used for a direct indication without NR-PDSCH scheduling information. If the flag bit is set to “false,” the remaining DCI bits may be used for NR-PDSCH scheduling. The direct indication may include one or more of: (1) a system information update (e.g., MIB, RMSI update, and / or OSI update); (2) a change or update to the number of SS blocks in an SS burst; (3) an update to the SS burst duty cycle; (4) a public alert (e.g., ETWS, CMAS, etc.); (5) a configuration for grant-free uplink resource updates; and (6) an update to the set of uplink resources associated with a set of downlink beams (e.g., SS blocks). When the WTRU receives a wake-up signal, the WTRU may send beam-related information or an indication of the selected beam by using the indicated or configured set of uplink resources.

[0112] In another embodiment, the DCI may be used for NR-PDSCH scheduling, direct indication, and beam-related information update. For example, two flag bits may be used in the DCI. A first state of the flag (e.g., “00”) may be used to indicate that the DCI carries NR-PDSCH scheduling information. A second state of the flag (e.g., “01”) may be used to indicate that the DCI carries a direct indication of a system information update without NR-PDSCH scheduling information. A third state of the flag (e.g., “10”) may be used to indicate that the DCI carries a beam-related information update without NR-PDSCH scheduling information. The beam-related information may include at least one of: (1) the number of SS blocks in an SS burst; (2) the SS burst duty cycle; and (3) the set or subset of SS blocks that are turned off (or on / off SS block status). For example, a BS (e.g., a gNB) may dynamically switch SS blocks (e.g., beams) on / off, and the BS may indicate which SS blocks are on or off. If the WTRU monitors an SS block that may be turned off, the WTRU may trigger or initiate one or more of the following procedures: a new beam search within an SS burst or an initial cell search. The beam-related information may further include a TX beam group for a common search space (or group-common NR-PDCCH).

[0113] Multiple total radiated power (TRP) based paging occasions are described herein. A WTRU may monitor POs associated with one or more TRPs to provide robustness for cases where one or more beams are blocked in a dynamic manner.

[0114] In one embodiment, one or more SS blocks in an SS burst may be associated with a beam. When multiple SS blocks in an SS burst are associated with a beam, the SS blocks may be assumed or considered to be QCLed at the beam point. SS blocks that are QCLed at the beam point may indicate that the PSS, SSS, and / or DM-RS of those SS blocks are QCLed at one or more QCL parameters (e.g., spatial Rx parameters).

[0115] 5 shows an example 500 of quasi-collocation (QCL) association among SS blocks 515, 520, 525, 530, and 535 in an SS burst 505 when multiple SS blocks 515 and 530 are associated with the same beam 540, which may be used in any combination with other embodiments described herein. As shown in FIG. 5, SS block #1 515 and SS block #4 530 may be associated with the same beam #3 540. The other SS blocks 520, 525, and 535 may be associated with different beams 545, 550, and 560. For example, SS block #2 520 may be associated with beam #1 545, SS block #3 525 may be associated with beam #550, and SS block #N 535 may be associated with beam #5 560. 5, SS block #1 515 and SS block #4 530 may be considered, assumed, or shown as being QCL'd 575 with respect to at least the beam (e.g., beam #3 540). However, SS block #1 515 and SS block #3 525 may be considered or assumed as not being QCL'd 570 because separate beams (e.g., beam #3 540 and beam #2 550) are associated with those SS blocks 515, 525. SS blocks 515, 520, 525, 530, 535 (e.g., the SSS and / or DM-RS of the PBCH in the SS block) and their associated POs (e.g., the DM-RS of the NR-PDCCH and / or NR-PDSCH for the associated PO) may be QCL'd. The WTRU may assume that the SS blocks 515, 520, 525, 530, 535 and their associated POs may be QCL'd.

[0116] In one embodiment, the BS may indicate to the WTRU the QCL association between SS blocks in an SS burst. For example, a subset of SS blocks associated with the same beam may be indicated to the WTRU. Based on the QCL association, the WTRU may combine, accumulate, or use one or more SS blocks in the SS burst for greater accuracy in time / frequency tracking and / or beam measurement. Specifically, a minimum SI may include the QCL association between SS blocks. One or more combinations or subsets of SS blocks may be predefined, and at least one of the combinations or subsets may be indicated to the WTRU at the minimum SI. Furthermore, the PBCH in each SS block may include QCL association information. For example, SS block indices used with or associated with the same beam may be indicated in the MIB. If the number of SS blocks in an SS burst is N, the WTRU may indicate the QCL association information. SS If so, N is used to indicate which SS blocks are associated with the same beam. SS A bitmap may be used. One or more subsets of SS blocks may be predefined, and at least one of the subsets may be indicated in the MIB.

[0117] The same sequence may be used for the PSS or SSS to indicate which beam it is associated with. For example, the WTRU may detect the sequence used for the PSS or SSS for one or more SS blocks. If the same sequence is used for one or more SS blocks in an SS burst, the WTRU may assume that those SS blocks are QCL'd or associated with the same beam.

[0118] In another embodiment, a beam ID may be indicated in each SS block. As described above, an SS burst may include multiple SS blocks (e.g., up to 64 SS blocks), and each SS block may be associated with a beam. Thus, there may be multiple beams (e.g., up to 64 beams) associated with an SS block. A bit field in the PBCH in the SS block may indicate which beam may be associated with the SS block. For example, six bits may be used to indicate the beam ID. This beam ID may be included in the PBCH of each SS block. If the beam ID is the same for two or more SS blocks, the WTRU may assume or consider that those two or more SS blocks are QCL'd or associated with the same beam. The WTRU may also measure beam quality from one or more SS blocks associated with the same beam in an SS burst. Since the beam itself is transparent to the WTRU from its perspective, the WTRU may measure beam quality using downlink signals (e.g., SS blocks). For example, the WTRU may measure 64 beam qualities based on 64 downlink signals for 64 beams. The CRC of the PBCH in each SS block may be masked with the beam ID.

[0119] A WTRU monitoring paging occasion (PO) with beam groups is described herein. The PO may be identified based on a beam identified during an initial access procedure. The WTRU may monitor a PO, which may be associated with one or more beams. Specifically, the WTRU may identify a subset of beams (e.g., one or more beams) from a downlink signal (e.g., an SS block). If the subset of beams includes multiple beams, the subset of beams may be associated with multiple SS blocks (e.g., a subset of SS blocks). The beams in the one or more subsets of beams may be non-overlapping or partially overlapping. A subset of beams may be interchangeably referred to as a beam tracking area (BTA), beam group, paging beam group, paging beam tracking area, and paging beam subset.

[0120] One or more subsets of beams may be pre-identified or pre-defined, and the subset of beams may be selected or identified based on beam quality measurements of the SS blocks. For example, the WTRU may measure the beam quality of the SS blocks in all subsets of beams, and the WTRU may identify the SS block that provides the highest beam quality. The WTRU may then select the subset of beams that contains the highest beam quality of the SS blocks (or the SS block that corresponds to the highest beam quality). The WTRU may also identify beam-specific POs for each beam in the selected subset of beams on the configuration information.

[0121] The WTRU may monitor POs (or beam tracking areas associated with a subset of beams or a subset of SS blocks) that are associated with a subset of beams or a subset of SS blocks. In a first type of PO monitoring, the WTRU may monitor all POs associated with the subset of beams. In a second type of PO monitoring, the WTRU may monitor a subset of POs that are associated with the subset of beams. Specifically, the subset of POs may be associated with a beam that may have the highest beam quality (or the best beam) within the subset of beams. The type of PO monitoring may be indicated by the network. For example, the network may indicate whether the WTRU is capable of monitoring a subset of POs that are associated with the subset of beams. Otherwise, the WTRU may need to monitor all POs that are associated with the subset of beams.

[0122] FIG. 6 illustrates an example 600 of beam tracking areas (BTAs) 617, 627, 637, 647 for paging monitoring in an SS burst 605, which may be used in any combination with other embodiments described herein. As shown in FIG. 6, a BS 610 may transmit multiple beams (i.e., beam a 650, beam b 655, beam c 660, beam d 665, beam e 670, beam f 675, and beam p 680). Each beam 650, 655, 660, 665, 670, 675, 680 may be spaced apart based on a vertical / horizontal domain. For example, beam a 650 may be steered at 90 degrees vertically and 0 degrees horizontally. Beam c 660 may be steered at 90 degrees vertically and 60 degrees horizontally. Thus, beam a 650 and beam c 660 may be located in the same vertical domain but different horizontal domains. Similarly, beam e 670 can be oriented at 60 degrees vertically and 0 degrees horizontally. In this case, beam a 650 and beam e 670 can be positioned in the same horizontal domain, but different vertical domains.

[0123] As described above, each beam 650, 655, 660, 665, 670, 675, 680 may be associated with its respective SS block 615, 620, 625, 630, 635, 640, 645. For example, as shown in Figure 6, beam a 650 may be associated with SS block #1 615, and beam b 655 may be associated with SS block #2 620. Similarly, beam f 675 may be associated with SS block #6 640, and beam p 680 may be associated with SS block #N 645. One or more SS blocks 615, 620, 625, 630, 635, 640, 645 (or one or more beams 650, 655, 660, 665, 670, 675, 680) may also be grouped into subsets of SS blocks (or subsets of beams) based on beam tracking areas 617, 627, 637, 647. For example, SS block #1 615 and SS block #2 620 may be grouped into a first subset of SS blocks corresponding to beam tracking area #1 617. Because SS block #1 615 is associated with beam a 650 and SS block #2 620 is associated with beam b 655, the subset of beams including beams a 650 and b 655 may be interchangeably referred to as beam tracking area #1 617. Similarly, SS block #3 625 and SS block #4 630 can be grouped into a second subset of SS blocks corresponding to beam tracking area #2 627. SS block #5 635 and SS block #6 640 can be grouped into a third subset of SS blocks corresponding to beam tracking area #3 637.Thus, the SS burst 605 may include K beam tracking areas (beam tracking area #1 617 through beam tracking area #K 647) based on the number of SS blocks 615, 620, 625, 630, 635, 640, 645 and / or the number of beams 650, 655, 660, 665, 670, 675, 680. As used herein, the term beam tracking area may be used interchangeably as beam tracking area number or beam tracking area index throughout this disclosure.

[0124] In one embodiment, a beam tracking area index may be used, and each SS block may include beam tracking area information. For example, the PBCH in the SS block may include a beam tracking area index. Specifically, the number of beam tracking areas may be determined based on the number of beams used in the SS burst. The number of SS blocks in the SS burst may also be used to determine the number of beam tracking areas. The beams in the beam tracking area may also be located in the spatial domain (e.g., vertically and / or horizontally) as described above. Finally, the beams in the beam tracking area may be evenly distributed in the spatial domain.

[0125] Figure 7 shows another example 700 of beam tracking areas (BTAs) 717, 727 for paging monitoring in an SS burst 705, which may be used in any combination with the other embodiments described herein. As shown in Figure 7, a BS 710 may have N SS blocks in an SS burst 705, and each SS block may be associated with a beam (e.g., 740, 745, 750, 755, 760). Although not shown in Figure 7, the BS 710 may use up to N (e.g., N = 64) beams in the SS burst 705. Each beam 740, 745, 750, 755, 760 may occupy one time unit for transmitting one paging resource (e.g., paging DCI) via the PDCCH. This means that the BS 710 can transmit the same paging resource five times to the WTRU via five beams 740, 745, 750, 755, 760 to indicate the control channel (e.g., PDCCH) that the WTRU needs to monitor for paging messages.

[0126] 7, each beam 740, 745, 750, 755, 760 may be associated with its respective SS block 715, 720, 725, 730, 735. For example, beam 1 740 and beam 2 745 may be associated with SS block #1 715 and SS block #2 720, respectively. SS block #1 715 and SS block #2 720 may be grouped into a first subset of SS blocks corresponding to beam tracking area #1 717. Similarly, beam 3 750 and beam 4 755 may be associated with SS block #3 725 and SS block #4 730, respectively. SS block #3 725 and SS block #4 730 may be grouped into a second subset of SS blocks corresponding to beam tracking area #2 727. Although not shown in FIG. 7, a WTRU may be configured with multiple subsets of SS blocks associated with multiple beams. For example, if the BS 710 sweeps 64 beams in the SS burst 705, there may be eight subsets of SS blocks. In this case, each of the eight subsets of SS blocks may include eight SS blocks corresponding to its respective BTA. A set of SS blocks may include all subsets of SS blocks, including the first and second subsets of SS blocks. As used herein, a set of SS blocks may be interchangeably referred to as a group of SS blocks. A subset of SS blocks may be interchangeably referred to as a subgroup of SS blocks.

[0127] In one embodiment, the WTRU may receive paging resources and a beam tracking area (BTA) configuration associated with the paging resources from the BS 710. The BTA configuration may include, but is not limited to, the number of BTAs 717, 727 and (1) association information between the BTAs 717, 727 and SS blocks 715, 720, 725, 730, 735, (2) association information between the BTAs 717, 727 and a subset of SS blocks, (3) association information between the BTAs 717, 727 and beams 740, 745, 750, 755, 760, or (4) association information between the BTAs 717, 727 and paging resources associated with the beams 740, 745, 750, 755, 760 (or SS blocks 715, 720, 725, 730, 735). The BTA configuration may be transmitted in a broadcasting message such as a system information block (SIB), an RRC message, etc. The WTRU may receive the paging resources and the BTA configuration while the WTRU is in an idle mode (e.g., RRC idle) or a connected mode (e.g., RRC connected).

[0128] Once the WTRU receives the paging resources and BTA configuration, the WTRU may monitor the quality of the beams 740, 745, 750, 755, 760 based on the downlink signals. For example, the quality of the beams 740, 745, 750, 755, 760 may be measured based on the PDCCH's reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), signal-to-interference-and-noise ratio (SINR), virtual block error rate (BLER), etc. The WTRU may perform beam quality measurements for all SS blocks 715, 720, 725, 730, 735 associated with the beams 740, 745, 750, 755, 760. The WTRU may then select an SS block among all SS blocks 715, 720, 725, 730, 735 based on the beam quality measurements. For example, if SS block #1 715 has the highest beam quality among all SS blocks 715, 720, 725, 730, 735 or meets a predetermined beam quality requirement, the WTRU may select SS block #1 715 for the best quality beam. The WTRU may then identify a BTA number (i.e., the first BTA) associated with the selected SS block (or a subset of SS blocks that includes the selected SS block) based on the BTA configuration. For example, if SS block #1 715 is selected for its highest quality beam, the WTRU may identify BTA #1 717 for monitoring the paging resource (i.e., beam 1 740) associated with SS block #1 715. Alternatively, or in addition, if the WTRU selects the first subset of SS blocks including SS block #1 715 as the beam containing the highest quality beam, the WTRU may identify BTA #1 717 for monitoring paging resources associated with both SS block #1 715 and SS block #2 720 (i.e., beam 1 740 and beam 2 745).

[0129] As described above, after identifying BTA numbers 717, 727, the WTRU may monitor paging resources (e.g., paging DCIs) associated with one or more SS blocks 715, 720, 725, 730, 735. In this case, the WTRU may reduce the number of SS blocks that the WTRU needs to monitor for paging resources by monitoring SS blocks 715, 720, 725, 730, 735 (or a subset of SS blocks) that correspond to the identified BTA numbers 717, 727. For example, if the WTRU identifies BTA #1 717 as the BTA for monitoring paging resources, the WTRU may only need to monitor the PDCCH associated with SS block #1 715 and SS block #2 720. If the WTRU receives a DCI using a P-RNTI from a PDCCH associated with SS block #1 717 or SS block #2 720, the WTRU can demodulate the PDSCH resource block indicated by the DCI. The WTRU can then decode the paging message (or PCH) carried on the PDSCH associated with the DCI. Because the number of beams 740, 745, 750, 755, 760 or SS blocks 715, 720, 725, 730, 735 that the WTRU needs to monitor is reduced by using BTAs 717, 727, the WTRU can save its battery consumption and extend battery life.

[0130] Based on the identified BTA number 717, 727, while monitoring the selected beam 740, 745, 750, 755, 760 or the paging resources associated with the selected SS block 715, 720, 725, 730, 735, if the beam quality of the selected SS block 715, 720, 725, 730, 735 falls below a predetermined threshold or does not meet a predetermined beam quality requirement, the WTRU may trigger a BTA update procedure to indicate a new candidate BTA or an updated BTA to the BS 710. For example, if the WTRU initially selects BTA#1 717 (i.e., SS block#1 715 and SS block#2 720) for paging resource monitoring, but the quality of the beam associated with SS block#1 715 and SS block#2 720 falls below a predetermined threshold, the WTRU may initiate beam quality measurements for all SS blocks 715, 720, 725, 730, 735 in SS burst 705, or for some of the SS blocks 715, 720, 725, 730, 735, such as neighboring SS blocks (e.g., SS block#3 725 and SS block#4 730). Based on the beam quality measurements for the other SS blocks 715, 720, 725, 730, 735, the WTRU may select another SS block (or a subset of SS blocks) that contains the highest quality beam or meets the beam quality requirements. For example, if the WTRU selects SS block #4 730 as the highest quality beam, the WTRU may identify BTA #2 727 as the BTA to be updated for paging resource monitoring. The WTRU may then monitor the paging resources associated with the updated BTA (i.e., BTA #2 727) or SS block #3 725 and SS block #4 730. The SS blocks associated with the updated BTA (i.e., SS block #3 725 and SS block #4 730) may be referred to as a second subset of SS blocks.The predetermined threshold may be received from the BS 710 in a broadcasting message such as a system information block (SIB), an RRC message, or the like.

[0131] To indicate the updated BTA (i.e., the second BTA) to the BS 710, the WTRU may use a random access channel (RACH) procedure. For example, the WTRU may transmit a signal (e.g., a PRACH preamble) associated with the updated BTA. The signal may include physical random access channel (PRACH) resources for the SS blocks 715, 720, 725, 730, and 735 associated with the updated BTA (e.g., a second subset of SS blocks). The PRACH resources may include time and frequency resources for the SS blocks 715, 720, 725, 730, and 735 associated with the updated BTA. The PRACH resources may be identified from PRACH configuration information received in a broadcasting message (e.g., an SIB) from the BS 710. The PRACH configuration information received from the BS 710 may include association information between the PRACH resources and the SS blocks 715, 720, 725, 730, and 735.

[0132] Once the BS 710 receives a signal indicating an updated BTA (i.e., a second BTA), the BS 710 may identify which beam has the best quality for the WTRU and select one or more beams 740, 745, 750, 755, 760 for transmitting a paging message. Specifically, the BS 710 may select the SS blocks associated with the updated BTA (i.e., a second subset of SS blocks) for transmitting paging resources (e.g., DCI) via the PDCCH. Using the updated BTA, the WTRU may monitor the SS blocks associated with the updated BTA (i.e., the second subset of SS blocks). If the WTRU receives DCI using a P-RNTI from the PDCCH associated with the updated BTA, the WTRU may demodulate the PDSCH resource blocks indicated by the DCI and decode the paging message (or PCH) carried on the PDSCH.

[0133] As described above, a WTRU may monitor the beam quality of an associated beam tracking area (BTA) based on downlink signals (e.g., SS blocks associated with the BTA). Specifically, the WTRU may monitor the beam quality of the associated BTA in each PO. A BTA may include one or more beams (e.g., one or more SS blocks). If the beam quality of all beams in the BTA is below a threshold, the WTRU may identify or declare a beam failure for the BTA. The beam quality may be based on the reference signal received power (RSRP) of the SS block associated with the BTA (e.g., RSRP measured from the SSS and / or PBCH in the SS block), etc. The threshold may be a predefined or predetermined value.

[0134] If the WTRU identifies or declares a beam failure of a BTA, the WTRU may search for a new candidate BTA that meets the beam quality requirements. If a new candidate BTA is found, the WTRU may change to the new candidate BTA, and the WTRU may indicate or report the change of BTA to the network. If a new candidate BTA is not found, the WTRU may trigger or perform an initial access procedure.

[0135] The BTA change indication or notification may be performed or used based on at least one of a PRACH resource, a WTRU-ID, a grant-free UL transmission resource, etc. Specifically, a set of PRACH resources may be reserved for the BTA change indication or notification. Each PRACH resource may be associated with a BTA, and the WTRU may identify PRACH resources that may be associated with the identified or changed BTA. The set of PRACH resources may be dedicated to the WTRU. The set of PRACH resources may also be configured per BTA.

[0136] When the WTRU transmits a PRACH for a BTA change indication, the WTRU-ID may be included or indicated. The WTRU may transmit a PUSCH associated with the PRACH, which may include the WTRU-ID, e.g., the WTRU-ID may be an IMSI, an s-TMSI, a modulo of the IMSI or s-TMSI, etc. The PUSCH associated with the PRACH may be transmitted in predetermined time / frequency resources, which may be dedicated to the respective PRACH resources configured for BTA change indication or notification.

[0137] A set of grant-free UL transmission resources may be used for the BTA change indication or notification. The grant-free UL transmission resources may include at least one of a sequence (e.g., a PRACH sequence), data (e.g., a PUSCH), and uplink control (e.g., a PUCCH). The WTRU may monitor the BS (e.g., a gNB) for confirmation. For example, after the WTRU sends a BTA change indication or notification, the WTRU may monitor the PDCCH or NR-PDCCH for confirmation of the BTA change in the specified or changed BTA.

[0138] In one embodiment, beam-related information for the WTRU may be stored in the network (e.g., MME or gNB). For example, when the WTRU switches from RRC connected mode to RRC idle mode, the latest beam-related information for the WTRU may be stored in the network for paging. The latest beam-related information may include at least one of an SS block, a beam ID, or a beam group ID. The SS block may be associated with a BTA. When the WTRU is paged, the MME may provide the beam-related information for the WTRU to a gNB within its paging tracking area.

[0139] In another embodiment, a BS (e.g., a gNB) may trigger a beam report for a paging transmission. For example, a common DCI or a group-common DCI may be transmitted or monitored in a common PDCCH or a common NR-PDCCH that may be used for all beams (or all BTAs), and the DCI may indicate or trigger a beam report from a WTRU or group of WTRUs.

[0140] The DCI may include a bit field that may trigger a beam report from a WTRU or a group of WTRUs. A group of WTRUs may be identified based on the associated SS block. For example, WTRUs monitoring POs associated with an SS block may be identified as a group of WTRUs. If the DCI triggers a beam report, WTRUs monitoring POs associated with the same SS block may report the beam. A set of PRACH resources may be used for beam reporting, and the set of PRACH resources to use may be indicated in the DCI. For example, one or more sets of PRACH resources for beam reporting may be pre-configured or pre-defined, and one of the sets may be indicated in the DCI when a beam report is triggered.

[0141] The DCI may also be monitored or received at a common paging occasion (PO) that may be monitored by all WTRUs. The time / frequency resources of the common PO may be configured or specified based on one or more of a paging cycle or cell-specific parameters. The paging cycle may be configured via broadcasting. Examples of cell-specific parameters may include, but are not limited to, a cell ID, a slot length, a slot number, a frame number, etc.

[0142] FIG. 8 shows an example procedure 800 for updating beam tracking areas (BTAs) for paging monitoring. For example, in step 805, a WTRU may receive from a base station (BS) a beam tracking area (BTA) configuration associating a set of synchronization signal (SS) blocks with each BTA. The set of SS blocks may include one or more subsets of SS blocks. The subset of SS blocks may include one or more SS blocks. The SS blocks in the set (or subset) of SS blocks may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) associated with the SS block. The WTRU may receive a master information block (MIB) via the PBCH associated with the SS block that includes the SS block configuration, such as the SS block number, and a subsequent control channel for further receiving broadcasting messages associated with the SS block. The BTA configuration may include the number of BTAs, association information between each of the BTAs and each of the SS blocks, association information between each of the BTAs and each of the subsets of the SS blocks, and / or association information between the BTAs and a set of SSs. The BTA configuration may be transmitted in a broadcasting message such as a Master Information Block (MIB), a System Information Block (SIB), an RRC message, etc.

[0143] In step 810, the WTRU may select a first SS block in a first subset of SS blocks based on measurements of beams associated with SS blocks in the set of SS blocks. For example, the WTRU may measure the quality of beams associated with SS blocks in the set of SS blocks based on the RSRP, RSSI, RSRQ, SINR, virtual block error rate (BLER) of the PDCCH, etc. If the WTRU finds an SS block that has the highest quality of the beam or meets a quality requirement, the WTRU may select that SS block as the first SS block. The first SS block may be included in the first subset of SS blocks.

[0144] In step 815, the WTRU may identify a first BTA associated with the first subset of SS blocks based on the BTA configuration. For example, because the first SS block is selected for its highest quality beam, the WTRU may identify the first subset of BTAs as the BTA (i.e., the first BTA) for monitoring paging resources. The WTRU may recognize an association between the first subset of BTAs and the first BTA based on the BTA configuration.

[0145] In step 820, the WTRU may monitor one or more physical downlink control channels (PDCCHs) for paging resources (e.g., DCI) associated with a first subset of SS blocks corresponding to the first BTA. If, in step 825, the measured quality of at least one beam associated with the first subset of SS blocks is below a predetermined threshold (or does not meet a beam quality requirement), the WTRU may transmit a signal to the base station (BS) indicating a second BTA (i.e., an updated BTA) associated with a second subset of SS blocks in step 830. The WTRU may identify a second SS block in the second subset of SS blocks based on the at least one measurement of the at least one beam associated with the set of SS blocks. The second SS block may be associated with the beam among the set of SS blocks that has the highest beam quality or meets a quality requirement. However, if in step 825 the measured quality of all beams associated with the first subset of SS blocks is greater than a predetermined threshold, then in step 820 the WTRU may continue to monitor one or more PDCCHs for paging resources (e.g., DCI) associated with the first subset of SS blocks corresponding to the first BTA.

[0146] The signal indicating the second BTA (or updated BTA) may include physical random access channel (PRACH) resources associated with a second subset of SS blocks corresponding to the second BTA. The PRACH resources associated with the second BTA may be selected based on a predetermined configuration (e.g., PRACH configuration information). Upon transmitting the second BTA, the WTRU may receive one or more paging resources (e.g., paging DCI) associated with the second BTA from the BS via the PDCCH. Upon receiving the one or more paging resources, the WTRU may receive a paging message (or PCH) from the BS based on the one or more paging resources.

[0147] The paging channel is used for purposes other than transmitting paging messages. For example, the paging channel may be used for system information update indications such as SI update, ETWS, CMAS, extended access barring (EAB), etc. However, in a beam-based system, the SI update may include beam-common SI and beam-specific SI. Triggering an SI update for all WTRUs when a beam-specific SI is updated may result in unnecessary WTRU battery consumption because those WTRUs are not monitoring the beam for which the information is updated. Separate SI update indications for beam-common SI and beam-specific SI may be required to avoid waking up WTRUs monitoring beams for which the system information is not updated. When a WTRU receives a beam-common SI update indication, the WTRU may receive updated SI for the beam-common system information. When a WTRU receives a beam-specific SI update indication, the WTRU may receive updated SI for the beam-specific system information.

[0148] In one embodiment, one or more types of SI update indications may be used. For example, a first type of SI update indication (e.g., Type-1 SI) may be used to update a first subset of SIs, which may be beam-common information. A second type of SI update indication (e.g., Type-2 SI) may be used to update a second subset of SIs, which may be beam-specific information.

[0149] Specifically, a first type of SI update indication (e.g., Type-1 SI) may be transmitted in a DCI in a common PO. The first type of SI update indication may be used to update beam-common system information, and the WTRU may monitor the DCI for a configured or identified beam-specific PO regardless of the associated SS block. The common PO may be transmitted using beam sweeping, and the DCI may be transmitted using one or more beams corresponding to the SS blocks in the SS burst. The common PO may also be transmitted in time / frequency resources that may be mutually exclusive to the time / frequency resources for the beam-specific PO. The periodicity of the time and frequency resources for the common PO may be explicitly configured by a broadcasting signal. For example, the time and frequency resources may be indicated based on the beginning or end of the SS burst. The time and frequency resources may be indicated using an offset from the beginning or end of the SS burst or a specific SS block (e.g., the first SS block). Each SS block may indicate the same time and frequency resources for the common PO using a different time and frequency offset. A bit flag may be used for a DCI to indicate whether it carries its associated PDSCH scheduling information or a Type-1 SI update indicator. If the DCI carries a Type-1 SI update indicator, then PDSCH scheduling information cannot be transmitted in the DCI.

[0150] A second type of SI update indication (e.g., Type-2 SI) may be transmitted in a DCI in a beam-specific PO. The second type of SI update indication may be used for beam-specific SI, and the WTRU may monitor the DCI if it is determined that the WTRU monitors the beam-specific PO. Specifically, each SS block may be associated with a beam and may have its associated PO, and the DCI for the Type-2 SI update indication may be monitored or received in the associated PO. A bit flag may be used for the DCI to indicate whether it carries its associated PDSCH scheduling information or a Type-2 SI update indication. If the DCI carries a Type-2 SI update indication, PDSCH scheduling information may not be transmitted in the DCI.

[0151] In another embodiment, a DCI in a common PO may be used to indicate both a first type of SI update indication and a second type of SI update indication. For example, the DCI in the common PO may include a Type-1 SI update indication field and a Type-2 SI update indication field. The WTRUs may monitor the DCI and, if updated, reacquire the corresponding SI. If the Type-1 SI update indication indicates a Type-1 SI update, all WTRUs may reacquire the corresponding SI. If the Type-2 SI update indication indicates a Type-2 SI update, the WTRUs may reacquire the corresponding SI if the updated SI is associated with the current serving beam (e.g., an SS block associated with a beam-specific PO).

[0152] The DCI in a common PO may carry a Type-1 SI update indicator and / or a Type-2 SI update indicator field. In an example, an RNTI may be used to indicate which type of SI update indicator is being transmitted in the DCI. For example, if a Type-1 SI update indicator is being transmitted, a first RNTI may be used to scramble the CRC of the DCI. If a Type-2 SI update indicator is being transmitted, a second RNTI may be used to scramble the CRC of the DCI. In another example, a Type-1 SI update indicator may be transmitted in the DCI along with a Type-2 SI update indicator associated with a beam or beam tracking area (BTA). For example, one or more Type-2 SI update indicators may be used for one or more beams or BTAs. In addition, the DCI may carry a Type-2 SI update indicator for a beam or BTA that may be indicated with at least one of an RNTI, a Type-1 SI update indicator, etc. The RNTI, which may be used to scramble the CRC of the DCI, may indicate which beam or BTA is associated with the Type-2 SI update indication. The beam or BTA may be associated with an SS block. The Type-1 SI update indication may be placed in the DCI regardless of which beam or BTA is associated with the Type-2 SI update indication.

[0153] Although features and elements are described above in particular combinations, one of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein can be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor associated with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer. [Explanation of symbols]

[0154] 100 Communication Systems 102a Receiver Unit (WTRU) 102b Receiver Unit (WTRU) 102c Receiver Unit (WTRU) 102d Receiver Unit (WTRU) 114a base station 114b base station 116 Air Interface 122 receiving elements

Claims

1. 1. A method for use in a wireless transmit / receive unit (WTRU), comprising: receiving a plurality of synchronization signal (SS) blocks included in a synchronization signal (SS) burst; selecting an SS block from the plurality of SS blocks, wherein a subset of PDCCH candidates for a paging occasion (PO) is associated with the selected SS block, and the PDCCH candidates for the PO are associated with a common search space; receiving a physical downlink control channel (PDCCH) transmission corresponding to one of the PDCCH candidates in the subset of PDCCH candidates, the PDCCH transmission including downlink control information (DCI), the DCI including scheduling information for a paging message; receiving the paging message via a physical downlink shared channel (PDSCH) transmission according to the scheduling information included in the DCI; A method comprising:

2. 2. The method of claim 1, wherein the subset of PDCCH candidates is determined based on an SS block time index associated with the selected SS block.

3. The method of claim 1, wherein the selected SS block and the subset of PDCCH candidates are associated with a common transmission beam.

4. 10. The method of claim 1, wherein each of the PDCCH candidates is associated with a respective control channel element (CCE).

5. 2. The method of claim 1, wherein each of the plurality of SS blocks in an SS block burst is associated with a respective subset of PDCCH candidates for the PO.

6. selecting the SS block based on measurements of the plurality of SS blocks included in the SS burst; The method of claim 1 further comprising:

7. 10. The method of claim 1, wherein the DCI includes an indication of a system information update.

8. 10. The method of claim 1, wherein the PO is determined based on a WTRU ID.

9. 2. The method of claim 1, wherein each of the plurality of SS blocks includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) transmission.

10. 1. A wireless transmit / receive unit (WTRU), comprising: transceivers, and Processor wherein the transceiver and the processor receiving a plurality of SS blocks included in a synchronization signal (SS) burst; selecting an SS block from the plurality of SS blocks, a subset of PDCCH candidates for a paging occasion (PO) being associated with the selected SS block, and the PDCCH candidates for the PO being associated with a common search space; receiving a physical downlink control channel (PDCCH) transmission corresponding to one of the PDCCH candidates in the subset of PDCCH candidates, the PDCCH transmission including downlink control information (DCI), the DCI including scheduling information for a paging message; receiving the paging message via a physical downlink shared channel (PDSCH) transmission according to the scheduling information included in the DCI; WTRU configured to:

11. 11. The WTRU of claim 10, wherein the subset of PDCCH candidates is determined based on an SS block time index associated with the selected SS block.

12. 11. The WTRU of claim 10, wherein the selected SS block and the subset of PDCCH candidates are associated with a common transmission beam.

13. 11. The WTRU of claim 10, wherein each of the PDCCH candidates is associated with a respective control channel element (CCE).

14. 11. The WTRU of claim 10, wherein each of the plurality of SS blocks in an SS block burst is associated with a respective subset of PDCCH candidates for the PO.

15. The transceiver and the processor Selecting the SS block based on measurements of the plurality of SS blocks included in the SS burst 11. The WTRU of claim 10, further configured to:

16. 11. The WTRU of claim 10, wherein the DCI includes a system information update indication.

17. The WTRU of claim 10 , wherein the PO is determined based on a WTRU ID.

18. 11. The WTRU of claim 10, wherein each of the plurality of SS blocks includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) transmission.

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