Method and apparatus for efficient utilization of SSB in new radio systems

Abstract

The present disclosure relates to methods and apparatus for efficient utilization of SSBs in a new radio system. Methods and apparatus for synchronization in a new radio (NR) system are disclosed. A frequency band may be determined, and the frequency band may correspond to a WTRU. Under the condition that the operating frequency band is a lower frequency, a synchronization signal block (SSB) index may be implicitly determined. Under the condition that the operating frequency band is a higher frequency, the SSB index may be determined based on a hybrid method, the hybrid method including utilizing both implicit and explicit methods to determine the SSB index. The configuration of the SSBs actually transmitted may be determined using a multi-level two-stage compressed indication, in which the SSB group is determined based on a coarse indicator, and the SSB actually transmitted using the SSB group is determined based on a fine indicator.

Description

[0001] This application is a divisional application of the invention patent application with the application date of April 30, 2018, application number 201880039464.X, and name “Method and device for efficient utilization of SSB in new radio systems”.

[0002] Citation of Related Applications

[0003] This application claims priority to U.S. Provisional Application No. 62 / 500,901, filed May 3, 2017; U.S. Provisional Application No. 62 / 519,532, filed June 14, 2017; and U.S. Provisional Application No. 62 / 543,119, filed August 9, 2017, the contents of which are incorporated herein by reference. Background Art

[0004] General requirements outlined by the ITU-R, Next Generation Mobile Networks (NGMN), and 3GPP broadly categorize emerging 5G system use cases into enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Different use cases may prioritize different requirements, such as higher data rates, improved spectral efficiency, lower power and improved energy efficiency, lower latency, and improved reliability. For various deployment scenarios, a wide range of frequency bands, from 700 MHz to 80 GHz, can be considered.

[0005] As carrier frequencies increase, significant path loss may be experienced, potentially limiting coverage. Transmissions in mmWave systems may also suffer from non-line-of-sight losses such as diffraction loss, penetration loss, oxygen absorption loss, and foliage loss. During initial access, the base station and wireless transmit / receive unit (WTRU) need to overcome these high path losses and discover each other. Summary of the Invention

[0006] Methods and apparatus for synchronization in a New Radio (NR) system are disclosed. In accordance with the disclosed subject matter, an operating frequency band may be determined. The frequency band may correspond to a WTRU. Where the operating frequency band is a lower frequency, a synchronization signal block (SSB) index may be implicit. Where the operating frequency band is a higher frequency, the SSB index may be determined based on a hybrid approach comprising determining the SSB index using both implicit and explicit methods. The configuration of the SSBs actually transmitted may be determined using a multi-level, two-stage compressed indication in which an SSB group is determined based on a coarse indicator and an SSB actually transmitted using the SSB group is determined based on a fine indicator. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention may be understood in more detail from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals denote like elements, and in which:

[0008] Figure 1A is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented;

[0009] Figure 1B is a diagram illustrating that according to an embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system illustrated in FIG.

[0010] Figure 1C is a diagram illustrating that according to an embodiment, Figure 1A A system diagram of an exemplary radio access network (RAN) and an exemplary core network (CN) used within the communication system illustrated in FIG.

[0011] Figure 1D is a diagram illustrating that according to an embodiment, Figure 1A A system diagram of another example RAN and another example CN used within the communication system illustrated in FIG.

[0012] Figure 2 An example showing a synchronization signal (SS) burst with a period of x ms and multiple SSBs in an SS burst;

[0013] Figure 3A A diagram showing determination of SS block (SSB) presence, index, and half radio frame timing;

[0014] Figure 3B An exemplary diagram showing determination of an SSB timing index indicator and a half radio frame indicator;

[0015] Figure 4 shows an example SSB index time indication using mixed CRC masking and control fields;

[0016] Figure 5 Indicates the SSB index time indication using mixed scrambling code and control field;

[0017] Figure 6 Indicates the SSB transmission method;

[0018] Figure 7 Indicates the SSB timing information indication method;

[0019] Figure 8 An SSB indication indicating the start point of adoption and its associated segment bitmap; and

[0020] Figure 9 Indicates the SSB indication using SSB grouping and simplified bitmap. DETAILED DESCRIPTION

[0021] Figure 1A is a diagram illustrating an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, 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-tailing unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), and the like.

[0022] like Figure 1A As shown in FIG, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112. However, it should be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For 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), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated process chain environments), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a UE.

[0023] The communication 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 communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. For example, the base stations 114a, 114b may be base transceiver stations (BTSs), Node-Bs, eNode Bs, Home Node Bs, Home eNode Bs, gNBs, NRNodeBs, site controllers, access points (APs), wireless routers, and the like. Although each of the base stations 114a, 114b is depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0024] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. 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 in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a specific geographic area, which may be relatively fixed or may vary over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, one for each sector of the cell. In an embodiment, base station 114a may employ multiple-input, multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals along a desired spatial direction.

[0025] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0026] 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, and the like. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may utilize Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0027] 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).

[0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0029] 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 radio access and NR radio access, for example, using dual connectivity (DC). 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 and from multiple types of base stations (e.g., eNBs and gNBs).

[0030] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0031] Figure 1A The base station 114b in the may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point, and may utilize any appropriate RAT to facilitate wireless connectivity in a local area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. 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 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 a femtocell. As Figure 1A As shown in FIG, base station 114b may be directly connected to Internet 110. Therefore, base station 114b may not be required to access Internet 110 via CN 106 / 115.

[0032] 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, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Data may have varying quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, and / or perform advanced security functions, such as user authentication. Although not described in detail in the text, the CN 106 / 115 may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Figure 1AAlthough not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ 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) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0033] 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 that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that utilize common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) of the TCP / IP suite of internet protocols. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include additional CNs connected to one or more RANs that may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0034] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The WTRU 102c shown in FIG. 1 may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0035] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 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 supply 134, a global positioning system (GPS) chipset, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any subcombination of the above elements while remaining consistent with an embodiment.

[0036] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of 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, or the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, although it is appreciated that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0037] The transmit / receive element 122 can be configured to transmit signals to a base station (e.g., base station 114a) or receive signals from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF and optical signals. It should be appreciated that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0038] Despite Figure 1B , the transmit / receive element 122 is depicted as a single element, however, 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.

[0039] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate over multiple RATs, such as NR and IEEE 802.11.

[0040] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from the speaker / microphone 124, keypad 126, and / or 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, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 may access information from and store data in any suitable type of 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, or the like. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0041] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd) batteries, nickel-zinc (NiZn) batteries, nickel-metal hydride (NiMH) batteries, lithium-ion (Li-ion) batteries, etc.), solar cells, fuel cells, and the like.

[0042] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine the location of the WTRU 102 based on the timing of received signals from two or more nearby base stations. It will be appreciated that the WTRU 102 may utilize any suitable location-determination method to acquire location information while remaining consistent with an embodiment.

[0043] The processor 118 may also 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 electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, 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.

[0044] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with particular subframes of both UL (e.g., for transmission) and downlink (e.g., for reception)) may be performed in parallel and / or simultaneously. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or signal processing by a processor (e.g., by a separate processor (not shown) or by the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with particular subframes of both UL (e.g., for transmission) or downlink (e.g., for reception)) may be performed in parallel and / or simultaneously.

[0045] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an 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.

[0046] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 160a may utilize multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0047] Each eNode-B 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. Figure 1C As shown in FIG, eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0048] Figure 1C The CN 106 shown in FIG may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although various of the above elements are described as being part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0049] 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 serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may also provide control plane functionality for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0050] 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 and from the WTRUs 102a, 102b, 102c. The SGW 164 may also perform other functions such as anchoring the user plane during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0051] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0052] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication 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. In addition, 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.

[0053] Despite Figures 1A-1D In the present disclosure, the WTRU is described as a wireless terminal, but it is contemplated that in some representative embodiments, such a terminal may (eg, temporarily or permanently) utilize a wired communication interface with a communication network.

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

[0055] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may access a distribution system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS, or may have an interface with the distribution system (DS) or another type of wired / wireless network. Traffic originating from outside the BSS for a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA for a destination outside the BSS may be sent to the AP for delivery to the corresponding destination. Traffic between STAs within a BSS may be sent through the AT, for example, where a source STA may send traffic to the AP and the AP may 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 (e.g., directly) between a source STA and a destination STA using direct link setup (DLS). In some representative embodiments, the DLS may utilize 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN utilizing an independent BSS (IBSS) mode may not have an AP, and STAs within or utilizing the IBSS (eg, all STAs) may communicate directly with each other. Herein, the IBSS mode of communication may sometimes be referred to as an "ad-hoc" mode of communication.

[0056] When utilizing the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or may be a width dynamically set through 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 some representative embodiments, such as in an 802.11 system, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented. For CSMA / CA, STAs (e.g., each STA) including the AP may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back off. One STA (e.g., only one station) may transmit in a given BSS at any given moment.

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

[0058] Very high throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. By combining contiguous 20 MHz channels, 40 MHz and / or 80 MHz channels can be formed. A 160 MHz channel can be formed by combining eight contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels (this may be referred to as an 80+80 configuration). For the 80+80 configuration, the channel-coded data can be passed through a segment parser that separates the data into two streams. Each stream can be subjected to inverse fast Fourier transform (IFFT) processing and time domain processing. The streams can be mapped onto the two 80 MHz channels, and the data can 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).

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

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

[0061] In the United States, 802.11ah can be used in the 902MHz to 928MHz band. In South Korea, the available band is 917.5MHz to 923.5MHz. In Japan, the available band is 916.5MHz to 927.5MHz. Depending on the country code, the total bandwidth available for 802.11ah ranges from 6MHz to 26MHz.

[0062] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with 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.

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

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

[0065] 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 also accessing other RANs (e.g., such as the eNode-Bs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use 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 an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect to the gNBs 180a, 180b, 180c while also communicating / connecting to another RAN, such as the eNode-Bs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles 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 serve as mobility anchors for the WTRUs 102a, 102b, 102c, while the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0066] Each of the gNBs 180a, 180b, 180c 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 UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and the like. Figure 1D As shown in , gNB180a, 180b, and 180c can communicate with each other through the Xn interface.

[0067] Figure 1DThe CN 115 shown in FIG may include at least one AMF 182 a, 182 b, at least one UPF 184 a, 184 b, at least one session management function (SMF) 183 a, 183 b, and may also include data networks (DNs) 185 a, 185 b. Although each of the above elements is described as part of the CN 115, it is appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0068] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the 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 of different PUD sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service being used by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and / or similar services. 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.

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

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

[0071] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may 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. Additionally, 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 the local data network (DN) 185a, 185b through the UPFs 184a, 184b via the N3 interface to the UPFs 184a, 184b and the N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0072] Given that Figures 1A-1D as well as Figures 1A-1D As described herein, one or more emulation devices (not shown) may perform one or more or all of the functions described herein with respect to one or more of the following: the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MMEs 162, SGWs 164, PGWs 166, gNBs 180a-c, AMFs 182a-ab, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein. 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 simulate network and / or WTRU functions.

[0073] The simulation device can be used to implement one or more tests of other devices in a laboratory environment and / or in a carrier network environment. For example, the one or more simulation devices can perform one or more or all of the functions described when being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. The one or more simulation devices can perform one or more or all of the functions described when being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for testing, and / or can utilize over-the-air wireless communication for testing.

[0074] The one or more simulation devices can perform the one or more functions, including all functions, when not being implemented / deployed as a part of a wired and / or wireless communication network. For example, the simulation device can be utilized in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement the testing of one or more components. The one or more simulation devices can be test equipment. The simulation device can utilize direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) to transmit and / or receive data.

[0075] LTE initial synchronization utilizes a cell search process during which the WTRU acquires time and frequency synchronization with a cell and detects the cell ID of that cell. The LTE synchronization signal is transmitted in the 0th and 5th subframes of each radio frame and is used for time and frequency synchronization during initialization. The WTRU can sequentially synchronize to the OFDM signal, time slot, subframe, half-frame, and radio frame based on the synchronization signal. The two synchronization signals are the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). The PSS can be used to determine time slot, subframe, and half-frame boundaries. It also provides the physical layer cell identity (PCI) within a cell identity group. The SSS can be used to determine radio frame boundaries. The SSS also enables the UE to determine the cell identity group, which can range from 0 to 167. After successful synchronization and acquisition of the PCI, the WTRU can decode the physical broadcast channel with the help of the cell-specific reference signal (CRS) and obtain master information block (MIB) information about the system bandwidth, system frame number (SFN), and PHICH configuration. The LTE synchronization signal and PBCH can be transmitted continuously with a standardized periodicity.

[0076] In LTE systems, a single beam is used for initial access. In New Radio (NR) systems, when multiple beams are used for initial access, synchronization signal bursts (SS bursts) may be used. SS bursts may be transmitted periodically, for example, approximately every 20 ms, and each SS burst may include one or more SSBs. One or more SSBs in an SS burst may be associated with one or more beams, and the number of SSBs in an SS burst may be determined by the gNB based on the number of beams in use at the gNB. For example, if N beams are used at the gNB, then N SSBs may be used or transmitted in an SS burst. Each SSB may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH (physical broadcast channel). Figure 2 An example of a synchronization signal (SS) burst with a period of x ms and multiple SSBs in the SS burst 200 is shown. Figure 2 As shown in FIG, each SS burst 200 may include SSBs 201 1 to N that circulate every x ms and each contain components of PSS 202, SS 203, and PCBH 204. As shown in the figure, the X-axis represents time and the Y-axis represents frequency.

[0077] In NR systems, synchronization signals (SS) may be used to achieve time synchronization between the gNB and the wireless transmit / receive unit (WTRU). More specifically, the WTRU needs to know the SSB information including the block index time indication of such blocks that will be used to decode block information and for time synchronization. In addition, some SSBs may be used to transmit synchronization signals while other SSBs may not be used to transmit synchronization signals. This may be due in part to the antenna and beam configuration at the gNB or Tx / Rx point (TRP). Thus, techniques are needed for obtaining SSB index time indications and reusing or using unused SSBs. Additionally, used SSBs may serve as reference points for the WTRU to make more accurate measurements. Access to unused SSB information may allow the WTRU to obtain or determine used SSB information. Thus, the WTRU may use known reference timing points for measurements.

[0078] According to the subject matter disclosed herein, a WTRU may be aware of SSB information, including a time indication, to obtain time synchronization between the gNB / TRP and the WTRU. Furthermore, the SSB may carry an index that may be used by the WTRU to obtain the time indication for time synchronization. This index may be indicated to the WTRU to support more accurate measurements and improve system efficiency and throughput. According to the subject matter disclosed herein, the proposed solution may also be used to obtain time synchronization or SSB information between devices such as gNBs, between TRPs, and between a gNB and a TRP.

[0079] Figure 3A

[0045] Efficient techniques for determining SSB presence, SSB index, and half radio frame (HRF) timing are presented in

[0046] . These techniques may be employed by any applicable component, such as a processor internal or external to the WTRU. At 310, a WTRU configuration may be detected, and at 320, a determination may be made as to whether a frequency band associated with the WTRU configuration detected at 310 is equal to, greater than, or less than a threshold frequency band. As a non-limiting example, the threshold frequency band may be 6 GHz, and at 320, a determination may be made as to whether the frequency band of the detected SSB is greater than (or equal to) or less than 6 GHz.

[0080] If the frequency band of the SSB is determined to be less than the threshold frequency band, then the SSB index may be implicitly determined from the PBCH demodulation reference signal (DMRS) sequence, as shown at 330. Alternatively, if the frequency band of the SSB is determined to be greater than or equal to the threshold frequency band, then a portion of the SSB index may be implicitly determined from the PBCH DMRS sequence, and the remainder of the SSB index may be explicitly determined from the PBCH payload, as shown at 335. The implicitly determined SSB index may be determined based on an energy level or correlation level of the signal, such that a bit in the SSB index may correspond to an energy level or correlation level of the signal that exceeds an energy or correlation threshold. A correlator may be employed to determine the energy level or correlation level. It will be appreciated that other techniques or thresholds may be used to detect bits in the SSB index.

[0081] As shown at 340 , HRF timing may be determined based on the implicit SSB index determination of 330 or the partially implicit and partially explicit SSB index determination of 335 .

[0082] At 350, a configuration of transmitted SSBs may be received in any applicable manner, such as via a multi-level two-stage compression indication. In the multi-level two-stage compression indication, as shown at 352, the configuration may include a first indicator that may include information that enables determination of which SSB groups are transmitted. The first indicator at 352 may be a coarse indicator that provides a group bitmap that enables determination of which SSB groups are transmitted. As shown at 354, the configuration may include a second indicator that may include information that enables determination of which SS / PBCH blocks are transmitted within an SS group. The second indicator at 354 may be a fine indicator that provides a mid-group bitmap that enables determination of which SS / PBCH blocks are transmitted within an SSB group, such as within a transmitted SSB group.

[0083] At 360, one or more actually transmitted SSBs may be monitored. The one or more actually transmitted SSBs may correspond to the SSBs whose configuration was received at 350.

[0084] Figure 3B1 shows an exemplary diagram of determining SSB presence, index, and HRF for an SSB having a frequency band greater than or equal to a threshold frequency band as disclosed herein. Figure 3A As shown in , for an SSB having a band greater than a threshold band, a portion of the SSB block may be determined implicitly and a portion may be determined explicitly. Figure 3B As shown in , at 365, a signal with a PBCH can be received, and a characteristic of the signal (such as a frequency band) can be determined to be greater than or equal to a threshold (such as a frequency threshold). Based on the determination, a hybrid technique for SSB index indication can be applied, such that an implicit determination is made at 370 and an explicit determination is made at 380. At 370, a portion 371 of the SSB index can be indicated based on PBCH DMRS detection. Additionally, based on PBCH DMRS detection, a half-radio frame indicator 372 can also be indicated. At 380, based on PBCH payload decoding, a portion 381 of the SSB index can be specified. Additionally, based on PBCH payload decoding, a half-radio frame indicator 382 can also be indicated.

[0085] At 385, the half radio frame indicator 382 indicated by the explicit PBCH decoding at 380 and the half radio frame indicator 372 indicated by the implicit PBCH DMRS detection at 370 may be compared. A match between these two half radio frame indicators 372 and 382 may result in the determination and / or confirmation of the half radio frame indicator h0 387.

[0086] At 390, a portion 371 of the SSB index indicated by explicit PBCH decoding at 380 and a portion 381 of the SSB index indicated by implicit PBCH DMRS detection at 370 may be combined. The combination may provide an SSB timing index indicator 395, for example, including the bits indicated by PBCH decoding 38 and PBCH DMRS detection 370. Additionally, the PBCH channel and payload may be detected to obtain other timing information 383, such as a system frame number.

[0087] As disclosed herein, the SSB index time indication can be based on the frequency band. The value L can vary based on the frequency band and can represent the maximum number of SSBs in an SS burst set. Higher frequency bands can employ a larger number of beams, while lower frequency bands can employ a smaller number of beams. Thus, for example, a larger L can correspond to a higher frequency band, while a smaller L can correspond to a lower frequency band. Additionally, the SSB index time indication, the SSB index frequency indication, or a combination of the SSB index time and frequency indications can be based on the frequency band. It should be understood that the solutions disclosed herein for the SSB index indication can be applied to the SSB index time and / or frequency indication. As a non-limiting example, the SSB index time and / or frequency indication can be received via a multi-level two-stage compression indication.

[0088] According to an embodiment, the SSB index time indication technique can be determined based on a threshold such that an SSB having a characteristic below the threshold can result in indicating the SSB index using a first method, while an SSB having a characteristic above the threshold can result in indicating the SSB index using a second different method. The threshold can be a threshold L value and can be an integer value such as 16. For a given SSB, if L < the threshold L value, such as L = 2, 4, or 8, then the SSB index can be indicated using the first method. The first method can include an implicit method that can employ, for example, CRC masking, sequence-based indication, indication using DMRS, scrambling, etc. According to such an implicit method, L CRC masks or L sequences, L hypotheses, L hypotheses using DMRS, scrambling, etc. can be used. If L > the threshold L value, such as L = 64, then the SSB index can be indicated using another method. For example, an explicit method, an implicit method, or a combination of an explicit method and an implicit method, such as a hybrid method, can be used to carry the SSB index in the NR-PBCH. It should be understood that the L value can be determined based on the configuration of the WTRU such that for a given configuration, such as the frequency band associated with the WTRU, the corresponding L value can be determined.

[0089] In one hybrid method, the SSB index indication can be based on L such that if L < T, where T = 16, L = 4, and 8, then an implicit SSB index indication is used, while if L >= T, where T = 16 and L = 64, then an explicit SSB index indication is used. In another hybrid method, the SSB index indication can be based on L such that if L < T, where for example T = 16, L = 4, and 8, then an implicit SSB index indication is used, while if L >= T, where for example T = 16 and L = 64, then a combination of implicit and explicit SSB index indications is used.

[0090] According to another hybrid approach, the LSB of the SSB index may be indicated using CRC masking or sequence-based indication, DMRS indication, scrambling, etc., while the MSB of the SSB index may be indicated in the payload or signal. For example, the K1 bit of the LSB may be indicated using PBCH CRC masking or sequence-based indication, DMRS indication, scrambling, etc., while the K2 bit of the MSB may be indicated in the PBCH payload or PBCH signal.

[0091] A unified hybrid approach for SSB indexing across different frequency bands may be implemented such that a WTRU or any applicable device may perform any one or a combination of the following: receive a PBCH signal and decode the PBCH channel, perform CRC demasking or sequence-based detection, detection using DMRS, descrambling, etc., obtain a K1 bit from the CRC demasking or sequence-based detection, detection using DMRS, descrambling, etc., and map and / or output the K1 bit as an SSB index time indication. For higher frequency bands, the WTRU or other applicable device may further perform any one or a combination of the following: obtain a K2 bit from the control field of the decoded PBCH channel, and output both the K1 bit and the K2 bit as the SSB index time indication bit. Here, K1 may be the LSB of the SSB index time indication, and K2 may be the MSB of the SSB index time indication.

[0092] Figure 4 An example SSB index time indication using hybrid CRC masking and control fields is shown. As shown, at 410, a PBCH signal is received. At 420, the PBCH channel is decoded and, at 430, the CRC is demasked. As a result of the CRC demasking at 430, a K1 bit can be obtained from the CRC mask map at 440. At 450, a determination is made as to whether the frequency meets a frequency band threshold. This determination can be made based on whether the frequency is greater than, equal to, or less than a threshold frequency. If the frequency is less than the threshold frequency, then the K1 bit is output as the SSB index time indication at 454. If the frequency is greater than the threshold frequency, then the K2 bit is obtained from the control field in the PBCH channel at 456, and, at 460, the K1+K2 bits are output as the SSB index time indication.

[0093] Table 1 shows an example CRC mask table for SSB index time indication with L = 4. As shown in the table, CRC mask #0 may correspond to SSB index time indication bit 00, while CRC mask #3 may correspond to SSB index time indication bit 11.

[0094] CRC masking SSB index time indication bit (L=4) CRC#0 00 CRC#1 01 CRC#2 10 CRC#3 11

[0095] Table 1: CRC Masking

[0096] According to another hybrid approach, scrambling can be used to indicate the SSB index and the LSB of the SSB index, while the MSB of the SSB index can be indicated in the payload or signal. For example, PBCH scrambling can be used to indicate the K1 bit of the LSB of the SSB index, while the K2 bit of the MSB of the SSB index can be indicated in the PBCH payload or PBCH signal.

[0097] For lower frequency bands, the WTRU or other applicable device may perform one or more of the following operations: receive a PBCH signal and descramble the PBCH channel, decode the PBCH channel, perform a CRC check, obtain a K1 bit from the scrambling mapping and CRC check, and output the K1 bit as an SSB index time indication. For higher frequency bands, the WTRU or other applicable device may additionally perform one or more of the following operations: obtain a K2 bit from the control field of the decoded PBCH channel, and output both the K1 bit and the K2 bit as SSB index time indication bits. K1 may be the LSB of the SSB index time indication, and K2 may be the MSB of the SSB index time indication.

[0098] Figure 5 An example SSB index time indication using a hybrid scrambling code and control field is shown. As shown, at 510, a PBCH signal is received. At 520, the PBCH signal is descrambled, and at 530, the PBCH channel is decoded. At 540, a CRC check is performed, and at 550, a K1 bit is obtained from the applicable scrambling code or scrambling code mapping. For example, scrambling code or scrambling code mapping may be performed for the PBCH, such as the PBCH DMRS and / or the PBCH payload. At 560, a determination is made as to whether the frequency meets a frequency band threshold. This determination may be made based on whether the frequency is greater than, equal to, or less than a threshold frequency. If the frequency is less than the threshold frequency, the K1 bit is output as the SSB index time indication at 564. If the frequency is greater than the threshold frequency, the K2 bit is obtained from the control field in the PBCH channel at 566, and the K1+K2 bits are output as the SSB index time indication at 570.

[0099] According to another hybrid approach, the SSB index indication may be based on partitioning. Here, the SSB index indication may be implicit for the least significant bit (LSB), such as the K1 bit, and explicit for the most significant bit (MSB), such as the K2 bit. The L threshold used in such solutions may be, for example, 16 or 64. Alternatively or additionally, the SSB index may be partitioned into two parts comprising an SSB index within an SS burst (SSB group) and an SS burst index within an SS burst set (SSB group index). The SS burst may be an SSB group, etc. The SS burst index may be an SSB group index, etc. The SSB index indication may be implicit for the SSB index within the SS burst, such as the K1 bit, and explicit for the SS burst index within the SS burst set, such as the K2 bit. The L threshold used in such solutions may be, for example, 16 or 64. Alternatively or additionally, the SSB index bits may be partitioned into two parts based on the K1 bit and the K2 bit. The SSB indication may be explicit for SSB indexing, such as K1 bit if only K1 bit is present, and may be implicit for K2-based SSB indexing if the total bits exceed K1 bit.

[0100] A partitioned SSB index indication can be explicit so that the portion of the SSB index can correspond to a portion of the payload on the NR-PBCH. For example, the K2 bit can be carried in the PBCH payload. The K2 bit can be encoded, rate-matched, and interleaved along with the other bits of the NR-PBCH and transmitted on a data resource element (RE). Explicit transmission may experience a delay when decoding, so that, for example, the SSB index may not be determined before the NR-PBCH is decoded at the receiver. Therefore, in order to detect the NR-PBCH consistently, a self-contained DMRS can be added. Although the DMRS may contain one or more sequences known to the receiver, different sequences and shifts can be applied to implicitly indicate a portion of the SSB index, such as a portion that is not explicitly indicated. For example, the K1 bit can be implicitly indicated using the DMRS, and the receiver can detect which hypothesis of the DMRS variation is most likely to be transmitted to implicitly decode the SSB index. Thus, the receiver does not have to wait for the entire PBCH to be decoded to determine the SSB index.

[0101] The DMRS may include a gold sequence, such that two M sequences may be generated, and two different cyclic shifts of these M sequences, m0 and m1, may be subjected to an exclusive-OR (XOR) operation with each other. The resulting sequence may be binary phase-shift keying (BPSK) modulated and subsequently repeated or truncated to fill the DMRS. The WTRU or other applicable device may utilize a combination of m0 and m1 to indicate the SSB index. Table 2 shows an example number of bits corresponding to the number of L, SSBs, and the number of m combinations (m0, m1).

[0102]

[0103] For example, for L=4, the m0 and m1 combinations of Table 3 may be applied. As shown, the 0SSB index may correspond to the (m0 m1) combination of (01).

[0104]

[0105] The DMRS may include an M sequence, where m0 may be used to indicate the SSB index. Table 4 shows the number of example bits and m0 values ​​corresponding to the number of L, SSBs. As shown, for example, 4 SSBs may correspond to 2 bits and 4 m0 m sequences.

[0106]

[0107] For example, for L=4, the m0 values ​​of Table 5 may be applicable. As shown, the 0 SSB index may correspond to a 0 m0 value.

[0108]

[0109] DMRS may include multiple M sequences, where the sequence ID and shift m0 may be used to indicate the SSB index.

[0110] DMRS may include a Zadoff-Chu (ZC) sequence. The ZC sequence may be used to indicate the SSB index, such that the CS may be used to indicate the SSB index, the root index of the ZC may be used to indicate the SSB index, or a combination of the CS and the root index may be used to indicate the SSB index. Table 6 shows the number of example bits and the number of CS values ​​corresponding to the number of L, SSBs

[0111]

[0112] For example, for L=4, the CS ZC values ​​of Table 7 may be applicable. As shown, the 0SSB index may correspond to the 0CS value, and the 3SSB index may correspond to the 36CS value.

[0113]

[0114] The DMRS may include a ZC sequence with a cover code, and the cover code may be another sequence such as an m-sequence. The ZC and cover code may be multiplied or XORed with each other, and m0 may be used to indicate the SSB index. Table 8 shows an example number of bits corresponding to the number of L, SSBs and the number of m0 values ​​as ZC multiplied or XORed with the cover code.

[0115]

[0116]

[0117] Alternatively, a combination of CS(ZC) and m0(M) can be used to indicate an SSB index, where the DMRS includes a ZC sequence with a cover code, and the cover code is another sequence such as an m-sequence. ZC and the cover code can be multiplied or XORed together. Table 9 shows an example number of bits corresponding to the number of L, SSBs and the number of CS(ZC) and m0(M-sequence) combination values.

[0118]

[0119] For example, for L=4, the CS (ZC) and m0 (M sequence) combination (CS, m0) shown in Table 10 may be applicable. As shown in the table, the 0 SSB index may correspond to the (0, 0) CS (ZC) and m0 (M sequence) combination (CS, m0), and the 3 SSB index may correspond to the (12, 1) CS (ZC) and m0 (M sequence) combination (CS, m0).

[0120]

[0121] According to one approach, the DMRS position or location may be used to indicate the SSB index. Table 11 shows an example number of bits and the number of DMRS positions corresponding to the number of L, SSBs.

[0122]

[0123] For example, for L=4, the DMRS positions shown in Table 12 may be applicable. As shown, the 0SSB index may correspond to position X, and the 3SSB index may correspond to position W.

[0124]

[0125] According to one approach, a combination of DMRS position / location and sequence can be used to indicate an SSB index. By DMRS position, a subset of bits, or for example, one or two bits, can be indicated. Bits not indicated by DMRS position can be indicated by one or more sequences. A combination of CS and / or m0 / m1 and / or position can be used to indicate an SSB index. Table 13 shows an example number of bits corresponding to L, the number of SSBs, and the number of CS (ZC), m0 (m sequence) and position combinations.

[0126]

[0127]

[0128] According to one approach, the DMRS phase rotation of an OFDM symbol can be used to indicate the SSB index. A subset of bits can be indicated by phase rotation, and another subset or the remaining bits can be indicated by sequence. For example, for multiple OFDM symbols, a phase rotation can be applied to the second or remaining N-1 PBCH OFDM symbols relative to the first PBCH OFDM symbol out of a total of N PBCH OFDM symbols. Alternatively, some bits can be indicated by phase rotation for some resource blocks (RBs), while other bits can be indicated by phase rotation for other RBs.

[0129] According to one approach, different scrambling codes may be used for PBCH OFDM symbols to indicate the SSB index. Table 14 shows the number of example bits and scrambling code combinations corresponding to the number of L, SSBs.

[0130]

[0131] Gold sequences or m-sequences can be generated using polynomials. For example, if the length of the repeating M-sequence is 31, then the following polynomial combination can be used:

[0132] g(x)=x 5 +x 2 +1

[0133] g(x)=x 5 +x 4 +x 3 +x 2 +1

[0134] g(x)=x 5 +x 4 +x 2 +x+1

[0135] For another example, if the length of the M sequence is 63, such as for a higher density DMRS, then the following combination of polynomials can be used:

[0136] g(x)=x 6 +x+1

[0137] g(x)=x 6 +x 5 +x 2 +x+1

[0138] g(x)=x 6 +x 5 +x 3 +x 2 +1.

[0139] It should be understood that other polynomials can also be used, such as irreducible primitive polynomials. In addition, the following equations can be used to define the cyclic shifts in the two sequences:

[0140]

[0141]

[0142] Where s1 and s2 correspond to two m-sequences of length L. In addition, m0 and m1 may correspond to two cyclic shifts, and the value of n may be 0 to L-1.

[0143] It is to be understood that any one or a combination of the methods described herein may be used for SSB index indication.

[0144] It is also to be understood that in addition to or as an alternative to the DMRS indication, the implicit solution of the hybrid indication may also use scrambling, CRC and / or redundancy version (RV).

[0145] A 1-bit repeat indication may also be used. This 1-bit repeat indication may be used for SSB index indication using DMRS, scrambling, CRC, and / or RV. This 1-bit repeat indication may also be carried in the PBCH payload. In addition, another 1-bit half-radio frame indication may also be used. This 1-bit half-radio frame indication may be used for indication using DMRS, scrambling, CRC, and RV. This 1-bit half-radio frame indication may also be carried in the PBCH payload. For example, this 1-bit half-radio frame indication may be indicated or carried in the scrambling and PBCH payload.

[0146] A method for performing SSB transmission such as with timing information indication is described herein.

[0147] According to one implementation, if a characteristic such as frequency is below a threshold, then an implicit indication method for SSB transmission is used. For example, if the frequency is below a threshold frequency of 6 GHz, then an implicit indication technique for SSB transmission is used. As a specific example of an implicit indication technique, a sequence-based indication method can be used. A number of bits such as X bits can be implicitly encoded using a sequence such as a reference sequence. The SSB index can be encoded in a scrambling sequence such as a PN code. DMRS can be used to encode an SSB index indication such that, for example, a scrambling sequence or PN code can be used in the DMRS to indicate the SSB index. Alternatively, the SSB index can be encoded in the CRC, in the scrambling for the payload, or using other implicit methods. The scrambling can be a function of the SSB index. Whether the same or different, the scrambling can be used for the payload in the DMRS and / or PBCH.

[0148] If a characteristic such as frequency is above a threshold, then a hybrid indication method for SSB transmission may be used. For example, if the frequency is equal to or above 6 GHz, then a hybrid indication method may be used. The hybrid indication method may employ both implicit and explicit indication techniques, such as a combination of DMRS and PBCH payload may be used. A certain number of bits of the SSB index, such as X bits, may be encoded in the PBCH DMRS sequence, and another number of remaining bits of the SSB index, such as Y bits, may be encoded in the PBCH payload. For convenience, the PBCH payload may reserve X+Y bits for the SSB index to facilitate encoding. Additionally, if the frequency is below a threshold, such as below 6 GHz in this example, then the Y bits may be reserved, or a subset of the Y bits may be reused for other purposes, such as an indication to assist the cell in defining the location of the SSB, or may be reused to support additional system operations, such as an indication to assist the cell in defining the presence / absence of an SSB.

[0149] Figure 6 An illustrative example of an SSB transmission method is shown. At 610, an SSB is transmitted via a downlink. The SSB transmission may be carrier frequency dependent or frequency band dependent. For example, at 620, it may be determined whether the carrier frequency fc is high, such that it is higher than or equal to a certain predefined carrier frequency fc1, where fc>=fc1. If it is determined that fc is greater than or equal to fc1, then at 650, the SSB index bits may be divided into two parts. At 660, the first part of the SSB index may be allocated X bits, and the second part of the SSB index may be allocated Y bits, where the total SSB index bits are Nt bits, where Nt bits are equal to X+Y bits. At 645, the first part of the SSB index, such as the allocated X bits, may be encoded via DMRS. The second part of the SSB index, such as the allocated Y bits, may be encoded in a PBCH payload such as a data channel, and may be encoded in the PBCH data channel using a coding operation of a polarization code.

[0150] As shown at 630, it can be determined that the carrier frequency fc is high, but not higher than a predefined carrier frequency fc1 such that fc < fc1, but higher than another predefined carrier frequency fc2 such that fc > fc2, and fc2 < fc1. If fc > fc2 and fc2 < fc1, then at 650, the SSB index can be divided into two parts. It should be understood that determinations 620 and 630 can occur simultaneously or synchronously and can be inherently based on the frequency fc without making a determination. If divided, then at 660, the first part of the SSB index can be assigned X bits, and the second part of the SSB index can be assigned Y bits. Or, if divided, then the second part of the SSB index can be assigned no bits. If divided and if the second part of the SSB index is assigned Y bits, then the total SSB index bits can be Nt, where Nt is equal to X + Y bits. If the second part of the SSB index is assigned no bits, then the total SSB index bits can be Nt = X bits. At 645, the first part of the SSB index can be encoded in the DMRS such that the X bits for the first part of the SSB index can be encoded using the DMRS sequence. If the second part of the SSB index is assigned bits, then at 665, the Y bits for the second part of the SSB index can be encoded in the PBCH data channel using an encoding operation such as a polar code. Or, the Y bits for the second part of the SSB index can be ignored or discarded. Or, the Y bits for the second part of the SSB index can be reused for other system information or control information.

[0151] As shown at 630, it can be determined that the carrier frequency fc is high, but not higher than a predefined carrier frequency fc1 such that fc < fc1, but higher than another predefined carrier frequency fc2 such that fc > fc2, and fc2 < fc1. If fc > fc2 and fc2 < fc1, then at 640, the SSB index may not be divided into multiple parts. It should be understood that determinations 620 and 630 can occur simultaneously or synchronously and can be inherently based on the frequency fc without making a determination. At 640, the entire SSB index can be assigned X bits. The total SSB index bits can be designated as Nt, where Nt is equal to X bits. At 645, the SSB index can be encoded in the DMRS such that the X bits for the SSB index can be encoded using the DMRS sequence.

[0152] As shown at 631, it can be determined that the carrier frequency fc is low and lower than a predefined carrier frequency fc2, such that fc < fc2. If fc < fc2, then the SSB index may not be divided into multiple parts. It should be understood that determining 620, 630, and 631 can occur simultaneously or synchronously and can be inherently performed based on the frequency fc without performing chip determination. The SSB index may be assigned Z bits. The total SSB index bits are Nt = Z bits. The SSB index may be encoded in the DMRS. The Z bits for the SSB index may be encoded using the DMRS sequence.

[0153] The PBCH data channel and a reference signal such as DMRS may be received. It should be understood that the PBCH data channel and the reference signal may be received separately or may be received together. A part of the SSB time index bits may be obtained by detecting the PBCH reference signal. Additionally, the PBCH data channel may be descrambled and decoded using a channel coding scheme, such as by a polar code. Another part of the SSB time index may be obtained by decoding the PBCH channel and the payload. By combining the part of the SSB time index obtained through the PBCH reference signal (such as DMRS) and the part of the SSB time index obtained through the decoded PBCH data channel, a complete set of bits for the SSB time index may be obtained. Additionally, the PBCH channel and the payload may be decoded to obtain other timing information such as the system frame number and / or the half radio frame number.

[0154] Figure 7 Illustrates an example method for SSB timing information indication. At 710, the WTRU may receive the PBCH reference signal and the data channel. At 720, the WTRU may detect the DMRS through the reference signal and may obtain a part of the SSB time index bits by detecting the DMRS reference signal. As shown at 725, the bits b2, b1, and b0 for a part of the SSB time index may be received. At 730, the WTRU may receive the PBCH data channel and may descramble and decode the PBCH channel using a channel coding scheme (such as by a polar code). As shown at 735, the WTRU may obtain another part of the SSB time index by descrambling and / or decoding the PBCH channel (such as bits b5, b5, and b3). At 740, by combining the part of the SSB time index obtained through the PBCH reference signal (such as DMRS) at 725 and the part of the SSB time index obtained through the decoded PBCH data channel at 735, a complete set of bits b0, b1, b2, b3, b4, and b5 for the SSB time index bits may be obtained. Additionally, the PBCH channel and the payload may be decoded to obtain other timing information such as the system frame number indicator 750 and / or the half radio frame number 760.

[0155] Disclosed herein are methods for performing sequence-based SSB transmission. According to a first method, the SSB index may be encoded in a sequence such as a DMRS for SSB transmission. According to one method, multiple sequences may be generated, wherein sequence A, or sequence type A, may be a function of a cell ID, and sequence B, or sequence type B, may be a function of a cell ID and an SSB index. Sequences such as sequence A and B may be generated using initialization, cyclic shift, frequency shift, and the like. Initialization of sequence A may be a function of a cell ID, and initialization of sequence B may be a function of a cell ID and an SSB index. The cyclic shift and / or frequency shift of sequence A may be a function of a cell ID, and the cyclic shift and / or frequency shift of sequence B may be a function of a cell ID and an SSB index. The sequences may be multiplied with a phase rotation based on the SSB index and may have the same or different lengths.

[0156] DMRS sequences can be mapped to DMRS REs. DMRS sequence A can be mapped to DMRS REs within a first group of PBCH OFDM symbols. DMRS sequence B can be mapped to DMRS REs within a second group of PBCH OFDM symbols. A group of PBCH OFDM symbols can include one or more OFDM symbols. For each PBCH OFDM symbol, DMRS sequences can be mapped to DMRS REs for lower frequency indices, subcarrier indices, or RE indices and higher frequency indices, subcarrier indices, or RE indices, separately and / or at different times. Lower frequency indices, subcarrier indices, or RE indices can be mapped before higher frequency indices, subcarrier indices, or RE indices.

[0157] According to another method, multiple sequences, where sequence A or sequence type A is a function of the cell ID, and sequence B or sequence type B is a function of the cell ID and the SSB index. Sequences such as sequence A and B can be generated using initialization, cyclic shift, frequency shift, etc. The sequences can be multiplied by a phase rotation based on the SSB index and can have the same or different lengths. The DMRS sequence length can be a function of the RE mapping method, such that if the DMRS is mapped to an RE that overlaps the SSS bandwidth, the DMRS can have a length of L1. If the DMRS is mapped to an RE that does not overlap the SSS bandwidth, the DMRS can have a length of L2. The length L1 may not be equal to the length L2, such that, for example, the length L1 may be equal to or less than the length L2.

[0158] The DMRS sequence may be mapped to the DMRS RE using any one of various methods or a combination thereof.

[0159] According to the DMRS sequence mapping method, a DMRS sequence A of length L1 may be mapped to a DMRS RE within a first group of PBCH OFDM symbols, and a DMRS sequence B of length L2 may be mapped to a DMRS RE within a second group of PBCH OFDM symbols. The length L1 may be equal to the length L2. When mapping a DMRS sequence to a DMRS RE, the RE may be mapped first in frequency, independently of mapping the RE in time. The RE may be mapped first in frequency, and then in time. For example, mapping a DMRS sequence to a DMRS RE may start with a lower frequency index, subcarrier index, or RE index, and then a higher frequency index, subcarrier index, or RE index. The mapping may then continue at a subsequent time, such as for an OFDM symbol index, a slot index, a non-slot index, or a microslot index.

[0160] According to another DMRS sequence mapping method, a DMRS sequence A of length L1 may be mapped to a DMRS RE in a DMRS RE that overlaps the SSS bandwidth within a first group of PBCH OFDM symbols. A DMRS sequence B of length L2 may be mapped to a DMRS RE in a DMRS RE that overlaps the SSS bandwidth within a first group of PBCH OFDM symbols and to a DMRS RE in all DMRS REs within a second group of PBCH OFDM symbols. Length L1 may be different from length L2. For example, length L2 may be equal to or greater than length L1. When mapping a DMRS sequence to a DMRS RE, the RE may be mapped in frequency separately from mapping the RE in time, such as first mapping the RE in frequency and then mapping it in time. For example, mapping the DMRS sequence to the DMRS RE may start with a lower frequency index, subcarrier index, or RE index, followed by a higher frequency index, subcarrier index, or RE index. The mapping may continue at a subsequent time, such as an OFDM symbol index, a slot index, a non-slot index, or a mini-slot index.

[0161] According to another DMRS sequence mapping method, a DMRS sequence A of length L1 may be mapped to a DMRS RE in a DMRS RE that overlaps with the SSS bandwidth within the first and second groups of PBCH OFDM symbols. A DMRS sequence B of length L2 may be mapped to a DMRS RE in a DMRS RE that overlaps with the SSS bandwidth within the first and second groups of PBCH OFDM symbols. The length L1 may be different from the length L2. For example, the length L2 may be equal to or greater than the length L1. When mapping a DMRS sequence to a DMRS RE, the RE may be mapped in frequency separately from mapping the RE in time, such as first mapping the RE in frequency and then mapping it in time. For example, mapping the DMRS sequence to the DMRS RE may start with a lower OFDM symbol index, slot index, or mini-slot index, followed by a higher OFDM symbol index, slot index, or mini-slot index. The mapping may continue at a subsequent time, such as an OFDM symbol index, slot index, non-slot index, or mini-slot index.

[0162] The DMRS RE position can be fixed or can be a function of the cell ID. The DMRS RE position can be a function of a shift, which can be a function of the cell ID. The DMRS RE position offset can be a function of a shift, which can be a function of the cell ID. The DMRS RE position and / or offset can be fixed or use a fixed offset.

[0163] Based on the techniques disclosed herein, an indication of used or unused SS blocks can be provided. Reusing unused SSBs for transmission can allow for more efficient utilization of system resources and improve system throughput. Unused SSBs can be indicated using one or more methods, including (but not limited to) a simple bitmap, a start point with duration and / or number of used SSBs, a mixed start point with a segmented bitmap, etc.

[0164] According to the simple bitmap method, an L-bit indicator can be used to indicate the unused SSB. The L-bit indicator can use a simple bitmap, such as 未使用 SSB, you can use N 未使用 The bit positions are marked as unused L bits. A value such as "0" can be used to mark an unused SSB, while a different value such as "1" can be used to mark a used SSB. For L=64 SSBs, a 64-bit signaling overhead is required.

[0165] According to the method with the start of duration and / or the number of used SSBs, two indicators can be used, so that one indicator can indicate the start of a used or unused SSB and the other indicator can be used to indicate the number of used or unused SSBs.起点 The starting point indicator may require log2(N 起点 ) bits. In addition, it may take log2(N 未使用 ) bits to indicate the unused SSB. Therefore, a total of log2(N 起点 )+log2(N 未使用 ) bits. For example, for N 起点 =64 and N 未使用 = 16, requiring a maximum of 10 bits of overhead. Using this approach can result in a significant reduction in signaling overhead compared to using a simple bitmap approach.

[0166] In a hybrid approach, such as a hybrid start with a segment bitmap, two indicators may be used such that one indicator may indicate the start and the other indicator may indicate the used or unused SSB associated with the indicated start. 起点 =4 and N SS_块,i = 16, where i = 1, 2, 3, 4, may require up to 2 + 16 bits of overhead. This indicates the starting point and the N associated with the i-th starting point. SS_块,i If extended to indicate two starting points, 2x(2+16)=36 bits of signaling overhead may be required.

[0167] Figure 8 An exemplary diagram illustrates a hybrid start-of-segment bitmap-based SSB indication method. As shown, the start of an SSB group is indicated by 810, and each group contains N SSBs 820. Bits 830 may correspond to each SSB 820 within the SSB group. As shown, the total number of SSBs is represented by L.

[0168] According to another method, SSB grouping can be used to indicate used and unused SSBs. The SSBs can be grouped so that for group i, each group can have N SS_grp,i SSBs. Grouping can include groups of equal or unequal size. After grouping, the number of resulting SS groups can be expressed as L SS_组 , where L SS_组 ≤ L. The group bitmap can be used to indicate L SS_组 SSB group, and L SS_组 bits can be used for group bitmap. For packets of equal size, the number of SS groups can be determined as follows:

[0169]

[0170] For example, for L=64, and for all i, N SS_grp,i =4,L SS_组= 16. Therefore, a total of 16 bits of signaling overhead may be required. SSB packetization can be done in the form of localized packetization or distributed packetization.

[0171] Figure 9 The SSB indication is represented by SSB grouping and a reduced bitmap, where the groups are of equal size. An SS bulk group is indicated by 910, and each group contains N SSBs 920. A total of K SS bulk groups 910 are provided. As shown in the figure, the total number of SSBs is represented by L. Each bit 930 corresponds to a group, such that the first group 910 is represented by b0 and the last group 910 is represented by b(K-1).

[0172] According to another approach, a multi-level index can be used to indicate used and unused SSBs. An SS burst index and an SSB index can be used. Two bitmap indicators can be used, such that a first bitmap indicator (group bitmap) can correspond to an SS burst index (e.g., an SSB group index), and a second bitmap indicator (in-group bitmap) can correspond to an SSB index. The first bitmap indicator can be used to indicate a used SS burst, while the second bitmap indicator can be used to indicate a used or unused SSB in an SS burst indicated as used. An SS burst can be an SSB group, etc. As disclosed herein, the first bitmap indicator can be used as a coarse indicator, while the second bitmap indicator can be used as a fine indicator.

[0173] According to another approach, the OFDM symbol index may be used to indicate inactive OFDM symbols within an SSB. The OFDM symbol index may be used to indicate inactive OFDM symbols across all SSBs. For each SSB, the used or unused OFDM symbols may be the same. Alternatively, the OFDM symbol index may be used to indicate inactive OFDM symbols for a portion of used SSBs. The number of OFDM symbols per time slot or subframe may be different, depending on, for example, the frequency band and / or subcarrier spacing (SCS). For example, for an SCS of 15 kHz, there may be 14 OFDM symbols per 2 time slots (or 7 OFDM symbols per time slot). For an SCS of 30 kHz, there may be 28 OFDM symbols per 2 time slots (or 14 OFDM symbols per time slot). For an SCS of 120 kHz: there may be 112 OFDM symbols per 2 time slots (or 56 OFDM symbols per time slot). For 240KHz SCS, there may be 224 OFDM symbols per 2 time slots (or 112 OFDM symbols per time slot).

[0174] An indication of an SSB measurement time window and duration may be provided so that used SSBs may be used for measurement purposes. The time location of the used SSBs may be provided and the time location of the used SSBs may facilitate measurements for the serving cell as well as neighboring cells. For example, a WTRU may receive the time location of the used SSBs and may facilitate measurements for the serving cell and neighboring cells. Additionally, unused SSBs may also be used for measurement purposes. For example, a WTRU may receive the time location of the unused SSBs and may utilize the time location of the unused SSBs to facilitate measurements such as interference measurements or signal strength from neighboring cells.

[0175] A WTRU or other applicable device may receive a set of parameters for used and / or unused SSBs. The parameters may include, but are not limited to, one or more measurement windows, timing parameters, duration parameters, offsets, and / or periodicity. The parameters may be provided via one or more indicators.

[0176] In idle mode, a set of parameters for used and / or unused SSBs may be received or provided via NR-PBCH, via remaining minimum system information, and / or via other system information.

[0177] In radio resource control (RRC) connected mode, a set of parameters for used and / or unused SSBs may be signaled via RRC signaling, MAC or MAC CE, and / or physical layer signaling such as NR-PDCCH or NR-ePDCCH.

[0178] According to the methods disclosed herein, SSBs may be reused. As disclosed herein, SSBs may be used to transmit synchronization signals and channels. To more efficiently utilize SSBs, other signals or channels may reuse subsets of SSBs to improve system throughput, reduce overhead, and increase spectral efficiency. SSBs may be reused for other signal or channel transmissions, such as for control and / or data transmission and reception, for CSI-RS transmissions such as those performed using TDM, FDM, or hybrid methods, and / or for paging downlink control information (DCI).

[0179] In addition, SSBs can be reused for control channel transmissions. For example, SSBs can be reused for control signals to allow URLLC transmissions, NR-PDCCH, NR-ePDCCH, paging signals or paging DCI, URLLC control channels, NR-PUCCH, and / or scheduling requests (SRs).

[0180] In addition, SSB can be reused for data channel transmission. For example, SSB can be reused for URLLC transmission or mini-slot transmission, such as for paging channel, paging PDSCH and / or URLLC data channel.

[0181] In addition, SSBs can be reused for reference signal transmission. For example, SSBs can be reused for CSI-RS transmission, such as for channel state information reference signal (CSI-RS) and / or sounding reference signal (SRS).

[0182] As described herein, unused SSBs may allow resources reserved for SSBs to be reused for other signal or channel transmissions. Additionally or alternatively, sets or subsets of SSBs may be transmitted, but may not be used for initial access or synchronization purposes. Such sets or subsets of SSBs may be transmitted to support other procedures, such as beam management. For DL ​​beam management, SSBs may be used to allow P-1, P-2, and P-3 procedures.

[0183] In addition, in idle mode, used and / or unused SSBs may be signaled. For example, the SSBs may be signaled via the NR-PBCH, where bits indicating unused SSBs may be carried in the NR-PBCH payload. Alternatively or additionally, the SSBs may be signaled via the remaining minimum system information, where bits indicating unused SSBs may be carried in the remaining minimum system information that may be scheduled by the NR-PBCH. Alternatively or additionally, the SSBs may be signaled via other system information, where bits indicating unused SSBs may be carried in other system information that may be scheduled by the remaining minimum system information.

[0184] In RRC connected mode, used and / or unused SSBs may be signaled via, for example, RRC signaling, MAC or MAC CE, and / or physical layer signaling such as NR-PDCCH or NR-ePDCCH.

[0185] Although various features and elements have been described above in specific combinations, one of ordinary skill in the art will recognize that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented using a computer program, software, or firmware contained in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired and / or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include (but are not limited to) read-only memory (ROM), random access memory (RAM), 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-ROMs and digital versatile disks (DVDs). A processor associated with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method for a user equipment, the method comprising: Determine the operating frequency band; determining a value L associated with the operating frequency band, the value L indicating a maximum number of synchronization signal blocks SSB in a synchronization signal SS burst; Under the condition that the value L is less than a threshold value L, determining a synchronization signal block SSB index based on a physical broadcast channel PBCH demodulation reference signal DMRS sequence; Under the condition that the value L is 64, the SSB index is determined by the following two methods: PBCH DMRS sequence, and PBCH payload; and monitoring SSBs transmitted via a downlink, wherein each SSB includes a primary synchronization signal PSS, a secondary synchronization signal SSS, and a PBCH, Wherein, under the condition that the value L is 64, the SSB index includes the least significant bit LSB and the most significant bit MSB, Among them, the LSB of the SSB index is determined based on the PBCH DMRS sequence, and Among them, the MSB of the SSB index is determined based on the PBCH payload.

2. The method according to claim 1, wherein The method further comprises: Receive the configuration of the actual transmitted SSB; and The SSB transmitted via the downlink is monitored based on the received configuration of the actually transmitted SSB.

3. The method according to claim 2, wherein the configuration of the SSB actually transmitted is indicated by a multi-level two-stage compression indication.

4. The method according to claim 3, The multi-level two-stage compression indicator includes a coarse indicator and a fine indicator: wherein an actually transmitted SSB group is determined based on the coarse indicator; and an actually transmitted SSB within the actually transmitted SSB group is determined based on the fine indicator.

5. A user equipment, comprising: a transceiver configured to monitor one or more synchronization signal blocks (SSBs) transmitted via a downlink, wherein each SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and a processor operatively connected to the transceiver and configured to: Determine the operating frequency band; determining a value L associated with the operating frequency band, the value L indicating a maximum number of SSBs in a synchronization signal SS burst; Under the condition that the value L is less than a threshold L value, determining an SSB index based on a PBCH demodulation reference signal DMRS sequence; and Under the condition that the value L is 64, the SSB index is determined by the following two methods: PBCH DMRS sequence, and PBCH payload; Wherein, under the condition that the value L is 64, the SSB index includes the least significant bit LSB and the most significant bit MSB, wherein the LSB of the SSB index is determined based on the PBCH DMRS sequence, and wherein the MSB of the SSB index is determined based on the PBCH payload.

6. The user equipment according to claim 5, wherein the processor is further configured to: Receive the actual transmitted SSB configuration, and Based on the received configuration of the actually transmitted SSB, the SSB transmitted via the downlink is monitored.

7. The user equipment according to claim 6, wherein the configuration of the SSB actually transmitted is indicated by a multi-level two-stage compression indication.

8. The user equipment according to claim 7, The multi-level two-stage compression indicator includes a coarse indicator and a fine indicator: wherein an actually transmitted SSB group is determined based on the coarse indicator; and an actually transmitted SSB within the actually transmitted SSB group is determined based on the fine indicator.

9. A method for a base station, the method comprising: operating a base station in an operating frequency band; Controlling the transmission of one or more synchronization signal blocks (SSBs), where each SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); wherein the operating frequency band is associated with a value L indicating a maximum number of SSBs in a synchronization signal SS burst; Wherein, under the condition that the value L is less than the threshold value L, the SSB index is determined based on the physical broadcast channel PBCH demodulation reference signal DMRS sequence, Wherein, under the condition that the value L is 64, the SSB index is determined by using both the PBCH DMRS sequence and the PBCH payload. Wherein, under the condition that the value L is 64, the SSB index includes the least significant bit LSB and the most significant bit MSB, Among them, the LSB of the SSB index is determined based on the PBCH DMRS sequence, and Among them, the MSB of the SSB index is determined based on the PBCH payload.

10. The method according to claim 9, further comprising: Transmit the actual SSB configuration transmitted; and The SSB is transmitted via the downlink based on the configuration of the actually transmitted SSB.

11. The method according to claim 10, wherein the configuration of the SSB actually transmitted is indicated by a multi-level two-stage compression indication.

12. The method of claim 11, wherein the multi-level two-stage compression indication comprises a coarse indicator and a fine indicator: Wherein an actually transmitted SSB group can be determined based on the coarse indicator; and an actually transmitted SSB within the actually transmitted SSB group can be determined based on the fine indicator.

13. The method of claim 9, wherein the base station is a gNB or a network element that is part of a gNB.

14. A base station, comprising: A processor configured to: operating the base station in an operating frequency band; and Controlling the transmission of one or more synchronization signal blocks (SSBs), where each SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH); and wherein the operating frequency band is associated with a value L indicating a maximum number of SSBs in a synchronization signal SS burst; Wherein, under the condition that the value L is less than the threshold value L, the SSB index is determined based on the physical broadcast channel PBCH demodulation reference signal DMRS sequence, Wherein, under the condition that the value L is 64, the SSB index is determined by using both the PBCH DMRS sequence and the PBCH payload. Wherein, under the condition that the value L is 64, the SSB index includes the least significant bit LSB and the most significant bit MSB, Among them, the LSB of the SSB index is determined based on the PBCH DMRS sequence, and Among them, the MSB of the SSB index is determined based on the PBCH payload.

15. The base station of claim 14, wherein the processor is further configured to: transmit the configuration of the actual transmitted SSB; and The SSB is transmitted via the downlink based on the configuration of the actually transmitted SSB.

16. The base station according to claim 15, wherein the configuration of the SSB actually transmitted is indicated by a multi-level two-stage compression indication.

17. The base station according to claim 16, The multi-level two-stage compression indicator includes a coarse indicator and a fine indicator: Wherein an actually transmitted SSB group can be determined based on the coarse indicator; and an actually transmitted SSB within the actually transmitted SSB group can be determined based on the fine indicator.

18. The base station according to claim 14, wherein the base station is a gNB or a network element that is part of a gNB.

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