Broadcast channel transmission and demodulation

Abstract

Methods and apparatus for broadcast channel transmission and demodulation, in particular for demodulating NR-PBCH signals, are disclosed. The method may include receiving a primary SS and an SSS. The received SSS signal may be used as a reference signal to detect a demodulation reference signal (DMRS) of the NR-PBCH. In one method, an NR-PBCH DMRS is associated with an SSB index to improve randomization in a synchronization process. The NR-PBCH payload may be demodulated using a PSS and / or an SSS as well as a DMRS. In one embodiment, the NR-PBCH DMRS may be mapped to a DMRS RE based on a first frequency mapping and a second time mapping.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of January 26, 2018, application number 202110938386.0, and name “Broadcast Channel Transmission and Demodulation”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 454,621, filed on February 3, 2017, U.S. Provisional Application Serial No. 62 / 500,702, filed on May 3, 2017, U.S. Provisional Application Serial No. 62 / 519,751, filed on June 14, 2017, and U.S. Provisional Application Serial No. 62 / 543,155, filed on August 9, 2017, the contents of each of which are incorporated herein by reference. Background Art

[0004] Legacy cellular systems such as the fourth generation Long Term Evolution (LTE) use a relatively simple synchronization process. For example, in LTE the physical broadcast channel (PBCH) always uses the same bandwidth as the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). Thus, in legacy LTE systems, both are allocated in the same (e.g., 6) resource blocks (RBs) in the frequency domain. Due to the frequency correlation, the receiver of a wireless transmit / receive unit (WTRU) can use the PSS and SSS as reference signals for PBCH demodulation.

[0005] However, in New Radio (NR), NR-PBCH may consume more bandwidth and may be allocated more RBs than NR-SSS. In NR, PBCH may occupy 24 RBs compared to 12 RBs of SSS. Therefore, in NR, SSS is no longer a good reference signal for PBCH demodulation due to inconsistency in frequency.

[0006] In addition, in LTE, PBCH can also use the common reference signal (CRS) as a reference signal for PBCH demodulation when the CRS exists. However, in NR, since NR tries to always minimize the signal, CRS does not exist. Therefore, CRS is no longer suitable as a reference signal for NR-PBCH demodulation. For improved performance of NR-PBCH demodulation, accurate channel estimation may be required, especially when considering a single detection. Therefore, a new reference signal (RS) design for accurate and efficient NR-PBCH demodulation can be used for the new NR-PBCH / NR-SS structure. Summary of the invention

[0007] Methods and apparatus for demodulating New Radio PBCH (NR-PBCH) signals are disclosed. The method may include receiving a primary SS (PSS) and a secondary synchronization signal (SSS). The received SSS signal may be used as a reference signal for detecting demodulation reference signals for the NR-PBCH. These demodulation reference signals may be interleaved with data on the NR-PBCH. In one method, the NR-PBCH demodulation reference signal (DMRS) is associated with a synchronization signal block (SSB) index to improve randomization during synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more detailed understanding may be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals represent like elements and in which:

[0009] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0010] Figure 1B It is shown that according to the embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system shown in FIG.

[0011] Figure 1C It is shown that according to the embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) used in a communication system shown in FIG.

[0012] Figure 1D It is shown that according to the embodiment, Figure 1A A system diagram of another example RAN and another example CN used in the communication system shown in FIG.

[0013] Figure 2 is an example of a New Radio (NR) Physical Broadcast Channel (NR-PBCH) multiplexed with a NR Primary Synchronization Channel (SS) (NR-PSS) and a NR Secondary Synchronization Channel (NR-SSS) multiplexed with a repeated NR-PBCH;

[0014] Figure 3 This is an example of NR-PBCH multiplexing with NR-PSSS and NR-SSS multiplexing with repeated NR-SS;

[0015] Figure 4 is an example of NR-PBCH dedicated demodulation reference signal design 1 using one antenna port;

[0016] Figure 5 is an example of NR-PBCH dedicated demodulation reference signal design 3 using two antenna ports;

[0017] Figure 6 is an example NR-PBCH hybrid dedicated demodulation reference signal;

[0018] Figure 7 is an example of a non-uniform density NR-PBCH dedicated demodulation reference signal;

[0019] Figure 8 is an example of non-uniform demodulation reference signal (DMRS) density according to PSS / SSS bandwidth;

[0020] Fig. 9 is an example of configurable NR-PBCH demodulation;

[0021] Fig. 10A It is the circuit diagram of 7-stage M-sequence phase shifter;

[0022] Fig. 10B It is a circuit of 6-stage M-sequence phase shifter;

[0023] Fig.11 is a flow chart of a process for receiver processing and information detection;

[0024] Fig.12 is an example of a QCL indicator aiding or assisting the initial access procedure and NR-PBCH demodulation;

[0025] Fig.13 is an example of using SS blocks associated with different precoders;

[0026] Fig.14 is an example of using SS blocks associated with different precoders, phase shifted on different PBCH messages;

[0027] Fig.15 is a diagram schematically combining two-port cyclic delay diversity (CDD) with diversity analog beamforming;

[0028] Fig.16 is an illustration of a schematic combination of digital and analog beamforming in the time domain;

[0029] Fig.17 is an illustration of a schematic combination of digital and analog beamforming in the time and frequency domains;

[0030] Fig.18 is a diagrammatic representation of a schematic combination of two-port space frequency block coding (SFBC) and analog beamforming for diversity;

[0031] Fig.19 is an example transmission point (TRP) transmission structure for initial access;

[0032] Fig. 20is an example single-stage exhaustive search beam scanning process;

[0033] Fig.21 is an example of a multi-stage WTRU hierarchical beam scanning procedure;

[0034] Fig. 22 is an example of a multi-stage TRP and TRP / WTRU hierarchical beam scanning process;

[0035] Fig.23 is an example of a multi-stage TRP / WTRU classification, TRP selective beam scanning process;

[0036] Fig.24 is a graphical representation of the signal-to-interference-and-noise ratio (SINR) performance results for various beam scanning processes;

[0037] Fig.25 is an example of an alternative TRP transport structure for initial access;

[0038] Fig.26 is an example of an exhaustive search beam scanning process in the replaceable signal phase;

[0039] Fig. 27 It is an example of a single-stage multi-radio frequency (multi-RF) chain TRP beam scanning process;

[0040] Fig.28 is an example of a single bit pattern frequency repetition;

[0041] Fig.29 is another example of bit pattern frequency swapping repetition;

[0042] Fig.30 is an example of a combined time and frequency swap repetition;

[0043] Fig.31 is a second example of a combined time and frequency swap repetition;

[0044] Fig.32 is an example of a sequence of length 62 that repeats in frequency;

[0045] Fig.33 is an example of NR-PBCH DMRS distribution of two sequences in a combined mode;

[0046] Fig.34 is an example of using cyclically shifted DMRS and STBI indication;

[0047] Fig.35 is an example of using cyclically shifted DMRS and STBI indication in a combined mode; and

[0048] Fig.36Table 1 in FIG. 1 is a row sequence representing different cyclic shifts for indicating SBTI. DETAILED DESCRIPTION

[0049] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 allows multiple wireless users to access such content by sharing system resources including wireless bandwidth. As an example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filtered pool multi-carrier (FBMC), etc.

[0050] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network components. 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 smart phone, 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, 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 an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0051] 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 facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112, by wirelessly interfacing with at least one of the WTRUs 102a, 102b, 102c, 102d. The base stations 114a, 114b may be, by way of example, a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single component, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network components.

[0052] The base station 114a may be part of the RAN 104 / 113, and the RAN may also include other base stations and / or network components (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage for wireless services in a specific geographic area that may be relatively fixed or changeable at any time. A cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, that is, each transceiver corresponds to a sector of the cell. In an embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology, whereby multiple transceivers may be used for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0053] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d via an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, millimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0054] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. 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), and the technology may use 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).

[0055] 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).

[0056] 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).

[0057] 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 LTE radio access and NR radio access together, for example using dual connectivity (DC) principles. Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNBs and gNBs).

[0058] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and / or GSM EDGE (GERAN), etc.

[0059] As an example, Figure 1A The base station 114b in the example may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may use any appropriate RAT to facilitate wireless connectivity in a local area, such as a business location, a residence, 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 establish a wireless local area network (WLAN) by implementing a radio technology such as IEEE 802.11. In an embodiment, the base station 114b and the WTRUs 102c, 102d may establish a wireless personal area network (WPAN) by implementing a radio technology such as IEEE 802.15. In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell by using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-APro, NR, etc.). Figure 1A As shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0060] 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. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. For example, the CN 106 / 115 may provide call control, billing services, mobile location-based services, pre-paid calls, Internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although in Figure 1A Although not shown, 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 or a different RAT as the RAN 104 / 113. For example, in addition to being connected to the RAN 104 / 113 employing NR radio technology, the CN 106 / 115 may also be in communication with other RANs (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0061] The CN 106 / 115 may also act 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 network devices that use a common communication protocol, such as TCP, User Datagram Protocol (UDP), and IP in the Transmission Control Protocol (TCP) / Internet Protocol (IP) Internet protocol suite. The network 112 may include a wired or wireless communication network owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may use the same RAT or a different RAT as the RAN 104 / 113.

[0062] 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 over different wireless links). Figure 1A The illustrated WTRU 102c 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.

[0063] Figure 1B is a system diagram showing an example WTRU 102. Figure 1B As shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keyboard 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0064] 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), and / or a state machine, etc. The processor 118 may perform signal decoding, 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 the transceiver 120 are depicted as separate components, but it should be appreciated that the processor 118 and the transceiver 120 may be integrated into one electronic component or chip.

[0065] The transmit / receive component 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive component 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, as an example, the transmit / receive component 122 may be a transmitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive component 122 may be configured to transmit and receive RF and light signals. It should be appreciated that the transmit / receive component 122 may be configured to transmit and / or receive any combination of wireless signals.

[0066] In addition, although Figure 1B102 as a single component, but the WTRU 102 may include any number of transmit / receive components 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive components 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0067] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers that allow the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0068] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keyboard 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may receive user input data from these components. The processor 118 may also output user data to the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store information in any suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, and / or a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0069] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power for use by other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (Ni-Cd), nickel-zinc (Ni-Zn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, and / or fuel cells, etc.

[0070] 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) related to the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information using any suitable positioning method while remaining consistent with an embodiment.

[0071] 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 or videos), 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 console module, an Internet browser, a virtual reality and / or augmented reality (VA / AR) device, an activity tracker, etc. The peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a direction sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a posture sensor, a biometric sensor, and / or a humidity sensor.

[0072] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes of the UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference due to hardware (e.g., blocking) or signal processing via a processor (e.g., a separate sensor (not shown) or via 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 specific subframes of the UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0073] Figure 1C1 is a system diagram of the RAN 104 and the CN 106 according to an embodiment. As described 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.

[0074] The RAN 104 may include eNode-Bs 160a, 160b, 160c, however it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. Each of the eNode-Bs 160a, 160b, 160c may 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 use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0075] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and / or user scheduling in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0076] Figure 1C The illustrated CN 106 may include a mobility management gateway (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the above components is described as being part of the CN 106, it should be understood that entities other than the CN operator may also own and / or operate any of these components.

[0077] 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 a control plane function to facilitate handover between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

[0078] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally route and forward user data packets to / 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 DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the contexts of the WTRUs 102a, 102b, 102c, and the like.

[0079] The SGW 164 may also 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.

[0080] 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. As an example, the CN 106 may include or communicate with an IP gateway, such as an IP Multimedia Subsystem (IMS) server, which serves as an interface between the CN 106 and the PSTN 108. The CN 106 may also provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0081] Although in Figures 1A-1D WTRUs are described in the specification as wireless terminals, but it is contemplated that in certain representative embodiments such terminals may use a (eg, temporary or permanent) wired communication interface with a communication network.

[0082] In a representative embodiment, the other network 112 may be a WLAN.

[0083] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic in and / or out of the BSS. Traffic initiated from outside the BSS to a STA may pass through the AP and may be delivered to the STA. Traffic initiated from a STA to a destination outside the BSS may be sent to the AP to be delivered to each destination. Traffic between STAs within a BSS may be sent through the AP, for example, where a source STA may send traffic to the AP and the AP may deliver traffic to a destination STA. Traffic between STAs within a BSS may be considered and / or referred to as end-to-end traffic. End-to-end traffic may be sent between (e.g., directly between) source and destination STAs using direct link establishment (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to as an "ad-hoc" communication mode.

[0084] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit a beacon on a fixed channel (e.g., a primary channel). The primary channel may be of fixed width (e.g., a 20 MHz wide bandwidth) or may be dynamically set in width via signaling. The primary channel may be an operating channel of the BSS and may be used by a STA to establish a connection with the AP. In certain representative embodiments, carrier sensing multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) including the AP may sense the primary channel. If the primary channel is sensed / detected and / or a specific STA determines that the primary channel is busy, the specific STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0085] A high throughput (HT) STA may use a 40 MHz wide channel for communication, for example, via a 20 MHz primary channel combined with an adjacent or non-adjacent 20 MHz channel to form a 40 MHz wide channel.

[0086] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels or by combining two discontinuous 80MHz channels (this can be called 80+80 configuration). For the 80+80 configuration, the data can be passed to the segment parser after channel coding, which can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing respectively. The stream can be mapped to two 80MHz channels, and the transmitting STA can transmit data. At the receiver of the receiving STA, the above-mentioned operation for the 80+80 configuration can be performed in reverse, and the combined data can be sent to the medium access control (MAC).

[0087] 802.11af and 802.11ah support Sub 1GHz operating mode. Compared with those 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, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support instrument control / machine type communication, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0088] WLAN systems (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah) that can support multiple channels and channel bandwidths include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA that is from all STAs operating in the BSS and supports the minimum bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, the entire available band may be considered busy, even if most of the band is still idle and available.

[0089] In the United States, the available frequency band that 802.11ah can use is from 902MHz to 928MHz. In South Korea, the available frequency band is from 917.5MHz to 923.5MHz. In Japan, the available frequency band is from 916.5MHz to 927.5MHz. Depending on the country code, the total bandwidth for 802.11ah is 6MHz to 26MHz.

[0090] Figure 1D 1 is a system diagram showing 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.

[0091] The RAN 113 may include gNBs 180a, 180b, 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, 180c may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may use beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum and the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and the gNB 180b (and / or the gNB 180c).

[0092] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. 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 varying numbers of OFDM symbols and / or persistently varying absolute time lengths).

[0093] 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 additionally accessing other RANs (e.g., the eNodeBs 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 (e.g., the eNode-Bs 160a, 160b, 160c). For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more of the gNBs 180a, 180b, 180c and one or more of the 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 and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0094] 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, user scheduling in UL and / or DL, network slicing support, dual connectivity, interworking between NR and E-UTRA, routing user plane data to a user plane function (UPF) 184a, 184b, routing control plane data to an access and mobility management function (AMF) 182a, 182b, and the like. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0095] Figure 1DThe CN 115 shown in the figure may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possibly a data network (DN) 185a, 185b. Although each of the above elements is depicted as part of the CN 115, it is understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0096] 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 serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, registration area management, NAS signaling termination, mobility management, and the like. The AMF 182a, 182b may use network slicing to customize the CN support for the WTRU 102a, 102b, 102c based on the type of service used by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced large mobile broadband (eMBB) access, services for machine-type communication (MTC) access, and the like. The AMF 162 may provide control plane functionality for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0097] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, and the like. The PDU session type may be IP-based, non-IP-based, Ethernet-based, and the like.

[0098] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate 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-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0099] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local data network (DN) 185a, 185b through the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0100] Given that Figures 1A-1D as well as Figures 1A-1D , one or more or all of the functions described herein with respect to one or more of the following may be performed by one or more emulation devices (not shown): WTRU 102a-d, base station 114a-d, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device described herein. An emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or emulate network and / or WTRU functions.

[0101] The simulation device can be designed to perform one or more tests on other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices can perform one or more or all functions when fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all functions when 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 perform testing using over-the-air wireless communications.

[0102] One or more simulation devices can perform one or more or all functions when not being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test environment of a test laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement the test of one or more components. One or more simulation devices can be test equipment. The simulation device can use wireless communication and / or direct RF coupling via RF circuits (e.g., which can include one or more antennas) to transmit and / or receive data.

[0103] Based on the general requirements set by the ITU Radiocommunication Sector (ITU-R), the Next Generation Mobile Networks (NGMN) group and the 3rd Generation Partnership Project (3GPP), a broad classification of use cases for converged 5G systems can be described as follows: enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Different use cases may focus on different requirements, such as higher data rates, higher spectral efficiency, low power and higher energy efficiency, lower latency, and higher reliability. A wide range of frequency bands from 700 MHz to 80 GHz may be considered for various deployment scenarios.

[0104] It is well known that as the carrier frequency increases, severe path loss becomes a critical limitation to ensure adequate coverage area. Transmissions in mmWave systems additionally suffer from non-line-of-sight losses such as diffraction loss, penetration loss, oxygen absorption loss, leaf loss, etc. During initial access, the base station and WTRU may need to overcome these high path losses and find each other. Using tens or even hundreds of antenna elements to generate beamformed signals is an effective way to compensate for severe path loss by providing sufficient beamforming gain. Beamforming techniques may include digital, analog, and hybrid beamforming.

[0105] Cell search is the process used by the WTRU to acquire time and frequency synchronization with a cell and detect the cell ID of the cell. During initialization, the LTE synchronization signal is transmitted in the 0th and 5th subframes of each radio frame and is used for time and frequency synchronization. As part of the system acquisition process, the WTRU synchronizes to OFDM symbols, time slots, subframes, half frames and radio frames based on the synchronization signals. The two synchronization signals are the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). The PSS is used to obtain time slot, subframe and half frame boundaries. It also provides the physical layer cell identity (PCI) within the cell identity group. The SSS is used to obtain the radio frame boundary. It also enables the WTRU to determine the cell identity group, which ranges from 0 to 167.

[0106] Following successful synchronization and PCI acquisition, the WTRU detects the Physical Broadcast Channel (PBCH) with the help of CRS and acquires MIB information related to system bandwidth, system frame number (SFN) and PHICH configuration. It should be noted that LTE synchronization signals and PBCH are continuously transmitted according to a standardized period.

[0107] It is agreed in NR that WTRU does not require blind detection of the NR-PBCH transmission scheme or the number of antenna ports. For NR-PBCH transmission, a single fixed number of antenna ports is supported. For NR-PBCH transmission, NR can use digital and analog beamforming techniques, especially for high frequency bands. Digital beamforming using multi-antenna techniques and / or analog beamforming using single or multi-port beamforming techniques can be considered in NR. For reference signals for NR-PBCH demodulation, NR can use synchronization signals (e.g., NR-SSS) or self-contained DMRS for NR-PBCH demodulation. If MRS is supported in the SS block, the mobility reference signal (MRS) can also be multiplexed in the SS block. The numerology of NR-PBCH can be the same or different from that of NR-SSS. Implementation of digital beamforming using multi-antenna techniques, analog beamforming using single or multi-port beamforming techniques, or hybrid schemes combining digital and analog beamforming have been considered for data transmission in connected mode. Similar techniques can also be considered in idle mode or for initial access and designed for broadcast channels, such as NR-PBCH, for optimal system performance.

[0108] NR-PSS and / or NR-SSS can be used as reference signals for NR-PBCH demodulation. Alternatively, a reference signal dedicated to NR-PBCH can be used. The reference signal can be self-contained within the NR-PBCH signal and channel. Even without additional signals or reference signals, the receiver is still able to demodulate the NR-PBCH signal and channel. The reference signal or demodulation reference signal (DMRS) used for demodulation is specific to NR-PBCH and can be multiplexed and embedded in the NR-PBCH resource. By doing so, the NR-PBCH dedicated demodulation reference signal (DMRS) can be used for NR-PBCH demodulation. The term DMRS used in this application may refer to one or more demodulation reference signals.

[0109] In order to use the NR-SS (NR-PSS or NR-SSS) as a reference signal for NR-PBCH demodulation, it may be preferred to time division multiplex (TDM) the NR-SS and the NR-PBCH.

[0110] Figure 2 NR-PBCH is shown to be multiplexed with NR-PSS and NR-SSS, where NR-PBCH, NR-PSS and NR-SSS are multiplexed in a TDM manner. NR-PBCH signals and channels can be repeated and can be set before or after NR-SS. Such a design can be used for, but is not limited to, carrier frequency offset compensation purposes. Figure 2 As shown, each of the PSS 204, 214, 226, SSS 206, 218, 228 and PBCH 208, 210, 216, 220, 224, 230 occupies the same frequency. In a first example, option 1 202, PSS 204 is transmitted before SSS 206, followed by the first PBCH 208 and the second PBCH 210. In option 2 212, PSS 214 is transmitted before PBCH 216, followed by SSS 218 and PBCH 220. Option 2 212 can be used to provide PBCH information before synchronization is completed. In option 2 212, PSS 214 is transmitted before PBCH 216, SSS 218 and PBCH 220. In another option, option 3 222, PBCH 224 is transmitted before PSS 226, followed by SSS 228 and PBCH 230. Option 3222 may allow PBCH information to be received before any synchronization information.

[0111] Similarly, Figure 33 is a timing diagram 300 showing the use of NR-SS signals in two different options 310, 320. NR-PSS or NR-SSS or both may be repeated and may be placed before or after NR-PBCH. Repeated NR-PSS or NR-SSS may also be used for, but not limited to, carrier frequency offset estimation or compensation purposes. Figure 3 As shown, in option 4 310, a first PSS transmission 312 may be transmitted before a second PSS transmission 314. An SSS transmission 316 may be transmitted after the second PSS transmission 314, followed by a PBCH transmission 318. In option 5 320, an SSS 322 may be transmitted before a PSS transmission 324. An SSS transmission 326 may follow the PSS transmission 324, and the SSS transmission 326 and the PBCH transmission 328.

[0112] Figure 4401, 420. In option 1 402 and option 2 420, one antenna port is used for NR-PBCH dedicated DMRS. In the first option, option 1 402, repeated NR-PBCH dedicated DMRS are placed at the same frequency position or subcarrier to help carrier frequency offset (CFO) estimation. In an example, DMRS 404 is at the same frequency position as DMRS 406, DMRS 408 is at the same frequency position as DRMS ​​410, DRMS ​​412 is at the same frequency position as DRMS ​​414, and DRMS ​​416 is at the same frequency position as DMRS 418. In the second option, option 2 420, another mode for NR-PBCH dedicated demodulation reference signal is used, in which DMRS is set with a fixed offset in the frequency domain to cover other frequency positions or subcarriers and / or obtain frequency diversity. For example, if the DMRS density is 1 / 6 for two NR-PBCH symbols, the DMRS in the second PBCH OFDM symbol can be offset by 3 REs relative to the first PBCH OFDM symbol. This can produce a perfect combination pattern of DMRS between two NR-PBCH OFDM symbols. The combined or joint DMRS in the two PBCH OFDM symbols can effectively change the DMRS density to 1 / 3 in lower Doppler channels and can improve channel estimation performance. The cost is that the DMRS cannot be used to estimate or correct CFO. However, in this case, the mapping of data REs can repeat some data REs when the PBCH data is repeated in the second PBCH OFDM symbol, which can be used for CFO estimation and compensation. As shown in option 2 420, DMRS 422 is offset from DMRS 430; DMRS 424 is offset from DMRS 432; DMRS 426 is offset from DMRS 434 and DMRS 428 is offset from DMRS 436.

[0113] Figure 5 is a third example of an NR-PBCH dedicated demodulation reference signal design 500 using two antenna ports in both options 502 , 540 . Figure 5NR-PBCH dedicated DMRS using two antenna ports is shown. In the first option 502, for each antenna port, repeated NR-PBCH dedicated DMRS 504-534 are placed in the same frequency position or subcarrier to help CFO estimation. In the second option, option 2 540, another mode of NR-BPCH DRMS ​​is used, in which the DMRS for the two antenna ports are set with a fixed offset in the frequency domain to cover other frequency positions or subcarriers and / or obtain frequency diversity. In option 2 540, DMRS1 542, 548, 550, 556, 558, 564, 566, 572 and DMRS2 544, 546, 552, 554, 560, 562, 568, 570 alternate in frequency.

[0114] In one or more embodiments, a hybrid dedicated demodulation reference signal (H-DMRS) may be used. For each antenna port, some of the repeated NR-PBCH dedicated DMRS may be placed in the same frequency position or subcarrier to help CFO estimation and other of the repeated NR-PBCH dedicated DMRS may be placed in different frequency positions or subcarriers and / or to obtain frequency diversity.

[0115] Figure 6 600 is a diagram of two different NR-PBCH hybrid dedicated demodulation reference signal (H-DMRS) designs 602, 620. Figure 6As shown, in hybrid 1-port mode 602, DMRS 604 may be at the same frequency location as DMRS 606 and DMRS 608 may be at a different frequency location than DMRS 610. DMRS 612 may be at the same frequency location as DMRS 614, and DMRS 616 may be at a different frequency location than DMRS 618. In the hybrid 2-port 620 approach, DMRS1 622 may be located at the same frequency position as DMRS1 624; DMRS2 626 may be located at the same frequency position as DMRS2 628; DMRS1 630 may be located at the same frequency position as DMRS2 632; DMRS2 634 may be located at the same frequency position as DMRS1 636; DMRS1 638 may be located at the same frequency position as DMRS1 640; DMRS2 642 may be located at the same position as DMRS2 644; DMRS1 646 may be located at the same frequency position as DMRS2 648; and DMRS2 650 may be located at the same frequency position as DMRS1 652. DMRSs are transmitted on two different ports. In an example, DMRS1 is transmitted from antenna port 1 and DMRS2 is transmitted from antenna port 2, and the two ports have a fixed offset in frequency. If the offset is zero, the DMRSs of the two antenna ports have the same frequency position.

[0116] In an embodiment, a non-uniform DMRS density may be used, which may use demodulation reference signals (DMRS) of different densities. In the OFDM symbol of NR-PBCH, a higher density DMRS may be set to assist channel estimation. However, a lower density DMRS may be set in the second OFDM symbol of NR-PBCH to reduce the overhead of DMRS. These DMRS may be the same as the DMRS for the same subcarrier in the first OFDM symbol of NR-PBCH, which may facilitate the estimation of CFO. This may reduce the code rate. Since the second symbol is closer to the SSS, channel estimation may be supported by using the SSS.

[0117] Figure 7 A non-uniform density NR-PBCH demodulation reference signal 700 is shown for use in two different configuration options 702, 720. In an embodiment, precoding may or may not be applied to the pilot subcarriers. Precoding may also be used to eliminate the common phase error for the second OFDM symbol, thereby improving the detection performance of NR-PBCH at the receiver.

[0118] The NR-PBCH / SS multiplexing implementation and the DMRS allocation implementation may allow efficient and high-performance NR-PBCH demodulation. Figure 4 and Figure 5It is shown how DMRS can be mapped to the same frequency position of symbols, for example to improve the performance of CFO estimation.The figures also show that DMRS can be mapped with a fixed frequency offset between symbols, which can improve channel estimation due to the resulting frequency diversity.

[0119] These performance-enhancing techniques can be used with Figure 6 A similar hybrid DMRS mapping is implemented as shown in FIG. Figure 7 In other embodiments, the PSS and / or SSS may be used to assist channel estimation when the DMRS density is low. This may be referred to as a diversity density (DD) approach. Figure 7 DD-DMRS1 port 702 and DD-DMRS2 port 720 embodiments are shown. In the DD-DMRS1 port 702 embodiment, the PSS signal 704 can be transmitted before the SSS signal 706. Before the PSS signal 704, DMRS708, 712, 714, 718 can be transmitted at a first time. After the SSS signal 706, DMRS signals 710, 716 can be sent at a second time. A lower number of DMRS can be transmitted the second time. The DMRS signals 708, 710, 714, 716 at the first and second times can partially overlap in frequency as shown. In the DD-DMRS2 port 720 example, more DMRS signals 726-744 can be transmitted compared to the DD-DMRS1 port 702 example. Similar to the 1-port option 702, these DMRS 726-744 can be transmitted before the PSS 722 and after the SSS 724.

[0120] In one example, NR-PSS and NR-SSS have different bandwidth allocations compared to NR-PBCH. For example, NR-PSS and NR-SSS may use 12 RBs, while PBCH uses 24 RBs. As a result, there are 12 RBs in PBCH that overlap with NR-PSS / NR-SSS, and the other 12 do not overlap with NR-PSS / NR-SSS. In the receiver, after cell ID detection, NR-PSS and NR-SSS can be considered as known sequences, which can be used as reference symbols for demodulating overlapping RBs of NR-PBCH. This technique can be used to improve performance and / or increase the efficiency of the design. Performance improvements can be achieved by allowing NR-PSS and / or NR-SSS to assist channel estimation, while efficiency can be achieved by allowing DMRS to be reduced or even completely removed within the SS bandwidth. Figure 8 This concept is shown. Figure 8 The left side 800 shows the design in which the SS block mapping order is NR-[PSS PBCH1 SSS PBCH2]. Figure 8The right side 830 shows the design of SS block mapping order is NR-[PBCH1 PSS SSS PBCH2]. The same design of DMRS can be applied to other possible mapping orders of NR-[PSS-SSS-PBCH1-PBCH2], NR-[PSS-PBCH1-PBCH2-SSS].

[0121] like Figure 8 As shown, the center RBs 806, 808 of NR-PBCH symbol one 802 or symbol two 804 have no DMRS or have a reduced density of DMRS. This increases the number of REs available for data transmission and thereby reduces the effective decoding rate for the same payload. If the channel estimation performance is similar, the reduced effective decoding rate can improve performance. If no DMRS is used for the center RB, the PSS 810 or SSS 812 or both can be used for channel estimation. If a reduced density DMRS is used for the center RB, the PSS 810, SSS 812 or both can be used with the existing DMRS as additional assistance for 2D channel estimation of the center RB. PBCH1 DMRS 814 and 818 can contain DMRS at full density. This is also the case for PBCH2 DMRS 816 and 820. It should also be noted that the reduction in NR-PBCH density can also depend on the distance from the NR-SSS. In the case of NR-[PSSP BCH1 SSS PBCH2] 800, both NR-PBCHs may have the same density for DMRS or may have no DMRS. However, in NR-[PBCH1 PSS SSS PBCH2] configuration 830, PBCH1 may have a higher DMRS density than PBCH2, even in RBs that overlap with NR-PSS and NR-SSS.

[0122] As shown in the NR-[PBCH1 PSS SSS PBCH2] configuration 830, the PSS 832 and SSS 834 are in the middle of the PBCH1 836 and PBCH2 833. The PBCH1 836 and PBCH2 838 consist of no DMRS or reduced density DMRS in the center frequency segments 836 and 838. The PBCH1 DMRS 840 and 844 may contain full density DMRS. This may also be the case for the PBCH2 DMRS 842 and 846.

[0123] Depending on the selected design, the DMRS density may be 1 / 3, 1 / 4, 1 / 6, or another density. If the DMRS density is 1 / 3, this may mean that one of three resource elements (REs) is used for DMRS. Similarly, if the DMRS density is 1 / 4 or 1 / 6, this may mean that one of four and six resource elements (REs) is used for DMRS, respectively.

[0124] The various options disclosed may provide different performance advantages and efficiency enhancements, which may be applied to different scenarios. To allow all possible options, simple signaling may be provided, for example, on the NR-SSS and / or the New Radio Third Synchronization Signal (NR-TSS) to indicate which option to use.

[0125] Fig. 9 900 is a flowchart illustrating in detail an exemplary execution of configurable NR-PBCH demodulation. The following example process may be used at a receiver. At 902, a NR-PSS signal may be searched. Timing and frequency information may be acquired using the NR-PSS / NR-SSS 904. A configuration indicator indicating a reference signal configuration carried on the NR-SSS may be decoded and the configuration indicator may be checked 906. As an example, Fig. 9 Two general reference configurations are shown, Configuration 1 908 and Configuration 2 910. In Configuration 1 908, a DRMS ​​self-contained PBCH reference signal is used. Figure 4-7 One of the various configurations shown in 910 may map the DMRS. This information may also be carried on the NR-SSS. In configuration 2 910, a joint SS / DMRS reference signal is provided. An exemplary scenario for configuration 2 910 may be when the PBCH bandwidth is larger than the SS bandwidth and the reduced DMRS density may be used in the overlapping bandwidth. This may be based on reference Figure 7 Or one or more disclosed embodiments of 8. Regardless of which is selected between configuration 1 908 and configuration 2 910, the estimated channel response can ultimately be used to demodulate 916 the NR-PBCH.

[0126] Figure 7 and Figure 8 An example of such a non-uniform DMRS mapping is shown for configuration 2 910. The exact density of DMRS in the overlap region can span from 1, which uses the same density as in the non-overlap region, to 0, which uses no DMRS in the overlap region. Additionally, the DMRS mapping portion can use Figure 4-6The same techniques shown in 906 may be used to represent the same techniques shown in 910. Finally, as in the case of configuration 1 906, the lower level configuration may also be signaled from the NR-SSS and / or NR-TSS. Channel estimation using only DMRS (configuration 1 908) may be performed 912. Alternatively, channel estimation using joint SS / DMRS (configuration 2 910) may be selected 914 when appropriate. The receiver may use a 2D (time-frequency) based algorithm for better joint interpolation in time and frequency. OFDM symbols for NR-PBCH may be received. Channel estimates for equalizing and detecting NR-PBCH symbols may be used and the symbols may be decoded 916 using a suitable channel decoder (e.g., using polarization decoding).

[0127] The NR-PBCH may be transmitted on N OFDM symbols. In a first embodiment, the NR-PBCH decoding bits may be mapped on REs in N PBCH symbols, where N is the number of PBCH symbols in an NR-SS block. In a second embodiment, the NR-PBCH decoding bits may be mapped on REs in a PBCH symbol, and the NR-PBCH symbol is copied to N-1 NR-PBCH symbols in an NR-SS block.

[0128] For example, for the case of N=2, the following may be used: In the first embodiment, the NR-PBCH decoding bits are mapped on the REs in the two PBCH symbols. In the second embodiment, the NR-PBCH decoding bits are mapped on the REs in the NR-PBCH symbol, and the NR-PBCH symbol is copied to the second NR-PBCH symbol NR-SS block.

[0129] In a first embodiment, in which NR-PBCH decoding bits are mapped on REs in two PBCH symbols: NR-PBCH decoding bits are mapped on REs in N PBCH symbols without repetition. NR-PBCH resources may be allocated in different ways. A frequency first mapping scheme may be used. Data to RE mapping may be mapped in a frequency first order. RE mapping may be performed frequency first and time second. RE mapping in time may be after RE mapping in frequency. RE mapping may be applied to data, DMRS, sequences, etc. In this case, the QPSK symbol generated from the data from the channel encoder is first mapped to the first NR-PBCH OFDM symbol, followed by the second or remaining N-1 NR-PBCH OFDM symbols. Time first mapping may be used. The QPSK symbol generated from the data from the channel encoder may be first mapped to the first RE of each NR-PBCH OFDM symbol, followed by the second RE of each NR-PBCH OFDM symbol, and so on. A hybrid approach may be used where the QPSK symbols generated from the data from the channel encoder are first mapped to the first (n) RB of each NR-PBCH OFDM symbol followed by the second (n) RB of each NR-PBCH OFDM symbol. 'n' may be a predefined or configured integer known to the transmitter and receiver.

[0130] In a second embodiment, where NR-PBCH decoding bits are mapped on REs in NR-PBCH symbols, NR-PBCH symbols are copied to a second NR-PBCH symbol NR-SS block, NR-PBCH decoding bits are mapped on REs in PBCH symbols with duplication. In a simple design, NR-PBCH data (and / or DMRS) may be copied to the second or remaining N-1 NR-PBCH OFDM symbols. In another embodiment, data frequency hopping may be performed. Data mapped to one RB in the first NR-PBCH symbol may be mapped to other RBs in the second NR-PBCH symbol. This frequency hopping pattern is known to the receiver and thus it is able to combine them to increase the decoding frequency. In this case, DMRS may not be frequency hopping. Thus, CFO may be estimated at the receiver using the DMRS position. In other embodiments, frequency hopping may be used only for 12 RBs that do not overlap with NR-PSS and NR-SSS. In one embodiment, an offset may be applied in the second PBCH symbol relative to the first PBCH symbol. The offset may be an offset in terms of the phase of the data symbol. The phase offset may be detected at the receiver and the implicit information is decodable. For example, if the phase difference between the first and second symbols is [0, pi / 2, pi, 3pi / 2], 2 bits of implicit information can be indicated. It may also have a known shift based on the cell ID. In this case, the purpose is not to indicate anything, but to use a cell-specific shift to randomize the data. The offset can be an offset in terms of the frequency position of the data symbol. Similar to the phase, the shift can be a known cell-specific shift to increase randomization or for blind decoding some bits. The shift can also be a frequency shift, a time shift, a phase shift, etc. or a combination of one or more of these.

[0131] In an embodiment, a hybrid design may be implemented. In this hybrid design, the first center 12 RBs of the two PBCH symbols may be filled with all data. The data may then be copied to the side 12 RBs, such as 6+6 on either side of the center. This design is important because all data symbols are in the center RBs. If the SNR is good, this allows the WTRU to detect the PBCH using a smaller bandwidth, such as the middle 12 RBs. In this way, the WTRU only needs to receive and demodulate the center 12 RBs, which may also save power. Frequency hopping may or may not be used here.

[0132] If frequency hopping is used, the center portion of the first symbol may be replicated over 12 RBs of the second symbol; the center portion of the second symbol may be replicated over 12 RBs of the first symbol. Since the receiver knows this pattern, it can carefully extract and combine the DMRS blocks before sending to the channel decoder. This can result in better performance at the WTRU at a lower SNR; combining at the receiver requires careful demapping of the REs.

[0133] In another embodiment, the RE mapping may be based on the cell ID and / or SS block ID. This embodiment may be motivated by interference randomization. Before detecting the NR-PBCH, the WTRU should have detected the cell ID using the NR-PSS / NR-SSS. Furthermore, in some cases, the SS block ID may be known before decoding the NR-PBCH. This is for example the case when the TSS is transmitted and the TSS carries the SS block ID or some a priori knowledge about the SS block index is available.

[0134] It is desirable to use DMRS RE mapping based on cell ID or SS block index or both. If the frequency position of the DMRS is based on the cell ID, it can reduce interference from neighboring cells. For example, this can include shifting the position of the DMRS for one, multiple, or all OFDM symbols of the NR-PBCH. In one or more embodiments, the terms SS block ID, SS block index, and SS block time index may be used interchangeably.

[0135] At the receiver, once the WTRU detects the NR-PSS / NR-SSS, the cell ID and / or SS block ID is known. The WTRU is able to identify the location of the DMRS for the NR-PBCH using the cell ID and / or SS block ID and a mapping function. The WTRU may then proceed to use the DMRS to perform channel estimation for the PBCH. PBCH demodulation and decoding may then be performed. Since different cells transmit DMRS at different locations, interference may be reduced, mitigated, or avoided.

[0136] To achieve better randomization, the sequence of DMRS (e.g., sequence or scrambling sequence) can also be based on the cell ID or SS block index or both. The sequence of DMRS (e.g., sequence or scrambling sequence) can also be based on other information, such as half-radio frame indication, in conjunction with, alone or separately from the SS block index or cell ID. DMRS can use any of different sequences. Options may include M sequence, Gold sequence, ZC sequence or PN sequence. The different parameters of these sequences can be a function of the cell ID or SS block index.

[0137] In any of the above cases, the DMRS used for PBCH can also be used as the DMRS for PDSCH. This is true for RBs occupied by PBCH. Rate matching can be used to convert the (512) decoded bits to all used data REs, which can vary depending on the DMRS design.

[0138] Different sequences can be used as DMRS for NR-PBCH. One of the sequences of interest is the maximum length sequence (M sequence). Due to the optimal noise-like properties and very good correlation properties, the M sequence can be used for dual purposes. The M sequence can be used to deliver information and can also be used as a reference symbol for NR-PBCH demodulation.

[0139] As an example, if 24 RBs are allocated for NR-PBCH, there can be 2 DMRS in each RB in each OFDM symbol. Therefore, 48 symbols are required as DMRS in each OFDM symbol. There may be design choices with a lower or higher number of DMRS based on a particular embodiment or implementation choice. The M sequence has a length of 2^M-1, making different options possible.

[0140] Fig. 10A A circuit 1000 is shown that is configured to generate an M-sequence of length 7. Fig. 10A As shown, there are 7 stages 1002-1014, representing 7 bits available for shifting. At each clock pulse of the circuit, the bit from stage 6 1012 is shifted to stage 7 1014, from stage 5 1010 to stage 6 1012, from stage 4 1008 to stage 5 1010, from stage 3 1006 to stage 4 1008, from stage 2 1004 to stage 3 1006, and from stage 1 1002 to stage 2 1004. The output of stage 7 1014 is ORed 1016 with the output of stage 6 1012 and fed to stage 1 1002. In this way, the input bits are continuously shifted to stage 1. The output 1018 from stage 7 1014 is shown. In this way, an M sequence of length 127 can be generated from a shift register of length 7 using 7 stages. This can be used for one or both OFDM symbols of NR-PBCH.

[0141] Fig. 10B An M sequence of length 63 is shown, which can be generated from a shift register 1020 of length 6. Thus, Fig. 10BOnly six stages 1022-1032 are shown in FIG. Output 1036 can be achieved from stage 6 1032. The OR operation 1034 of stage 5 1030 and stage 6 1032 can be fed to stage 1 1022. The sequence can be used for one or two of the OFDM symbols of NR-PBCH, with some repetitions or padding and some known symbols. For example, all 1s are padded to match the sequence length to the required number of DMRS. It is also possible to use a shift register of length 5 to generate an M sequence of length 31 and repeat it to cover all DMRS of each OFDM symbol. The same or different sequences can be used for other OFDM symbols. It is also possible to concatenate two different M sequences of the same or different lengths. This can achieve two shifts at the cost of higher correlation. This increases the amount of information transmitted at the expense of detection confidence. However, if the sequence is long, this can be an important option. The M sequence can also be scrambled with another sequence or another PN sequence can also be used. The parameter class shift or polynomial of the sequence can be a function of the cell ID. This can achieve orthogonal DMRS between different cells.

[0142] M sequences of larger lengths may provide better correlation properties. These sequences may use different shifts. Using different shifts, 31, 62, or 127 M sequence bit lengths may be used to implicitly indicate [5,6,7] information bits. An option may include, but is not limited to, indicating an SS block index, indicating details to assist in channel decoding of NR-PBCH (including information about polarization codes and beam IDs). This may also be used for any other information that requires very low latency. If DMRS is not used to indicate the SS block ID but it is known prior to decoding NR-PBCH, a parameter-like shift or polynomial of the sequence may be a function of the SS block ID. The shift may be, but is not limited to, a frequency shift, a time shift, a phase shift, a position shift, etc. A combination of these shift types may also be used.

[0143] Fig.111100 is a flowchart showing a process for exemplary receiver processing and information detection. The receiver may first acquire time and frequency 1102 using NR-PSS and NR-SSS. The receiver may receive 1104 OFDM symbols for NR-PBCH. DMRS RE allocation may be a function 1106 of the cell ID and / or SS block ID, and DMRS RE mapping may be found based on the cell ID and / or SS block ID. The SS block ID may be implicitly indicated 1108 in the DMRS, and the receiver may use 1110 the NR-PSS to estimate the channel and pre-balance the REs containing the DMRS for the NR-PBCH. The receiver may then extract 1118 the frequency domain symbols for the DMRS for the NR-PBCH. These symbols are associated with the original M sequence, which is used to generate the DMRS for the PBCH. A strong peak is given at one of the offsets. This gives information embedded in the DMRS, similar to the SS block index. If multiple M sequences are used and careful extraction and correlation are performed, the transmission shift of each M sequence may be identified. Using the detected shift, a local copy of the DMRS may be generated. This can then be used to detect and decode the NR-PBCH. The DMRS sequence can be a function 1112 of the cell ID and / or SS block ID and a local replica based on the DMRS can be generated based on the cell ID and / or SS block ID. The local replica of the DMRS can be used for channel estimation for the NR-PBCH and for demodulating / decoding the NR-PBCH. The local replica can be found 1114 via a lookup table 1116 in a local table or database.

[0144] In another embodiment, the ZC sequence can be used as a DMRS for NR-PBCH. The ZC sequence can be used to deliver information using different cyclic shifts and also used as a reference symbol for demodulating NR-PBCH. As an example, if 24 RBs are allocated for NR-PBCH, there can be 2 DMRS in each RB in each OFDM symbol. Therefore, in each OFDM symbol, N symbols may be required for DMRS. In one embodiment, N may be 48. The length of the ZC sequence can be selected to match the number of DMRS. The optimal root of the ZC sequence can be determined by simulation.

[0145] It is also possible to concatenate two different ZC sequences of the same or different lengths. The ZC sequence can also be scrambled with another PN sequence or M sequence. For example, the root of the ZC sequence or the parameter of the cyclic shift of the ZC sequence can be a function of the cell ID. This can achieve orthogonal DMRS between different cells. The longer the length of the ZC sequence, the better the correlation properties. These sequences can be used with different cyclic shifts. Using different shifts, it is possible to carry [4,5,6] information bits for ZC sequences of lengths of 31, 62, and 127, respectively, which can be used to indicate information used to assist in channel decoding of NR-PBCH. This can include information about polarization coding and / or decoding, including beam ID. Different roots of ZC sequences may also be used. The WTRU may be able to blindly identify the ZC sequence used. This can also be used to convey implicit information. This can be used for any other information that requires very low waiting time. If DMRS is not used to indicate the SS block ID but it is known before decoding the NR-PBCH, the parameter class root of the ZC sequence or the cyclic shift of the ZC sequence can be a function of the SS block ID.

[0146] For receiver processing, the following process may be used to detect the information. The receiver may first use the NR-PSS / NR-SSS to acquire timing and frequency. The receiver may receive OFDM symbols for the NR-PBCH. The DMRS RE allocation may be a function of the cell ID and / or SS block ID and the DMRS RE mapping may be acquired based on the cell ID and / or SS block ID. The DMRS sequence may be a function of the cell ID and / or SS block ID and a local copy of the DMRS may be generated based on the cell ID and / or SS block ID. The local copy of the DMRS may be used for channel estimation for the NR-PBCH and to demodulate / decode the NR-PBCH.

[0147] Gold sequences can also be used for DMRS. Gold sequences can be generated by multiplying two M sequences by each other. These M sequences can be generated from irreducible primitive polynomials and the two polynomials should be a preferred pair. The following process can be used for this design.

[0148] Two M sequences can be generated from the polynomial of the preferred pair. Two different shifts (m0 and m1) are used for the two M sequences. They are then XORed. The sequence is BPSK modulated and then repeated or clipped to meet all DMRS.

[0149] If the chosen length of the M-sequence is 31, which can be repeated, then the following combination of polynomials can be used. The octal values ​​are 45, 75, 67, in order.

[0150] For: g(x) = x5 + x2 + 1

[0151]

[0152] For: g(x) = x5+x4+x3+x2+1

[0153]

[0154] For: g(x) = x5+x4+x2+x+1

[0155]

[0156] Other irreducible primitive polynomials are not excluded (octal values ​​51, 37, 73). The following initializations can be used but other initializations are not excluded:

[0157] x(0)=0,x(1)=0,x(2)=0,x(3)=0,x(4)=1

[0158] If the length of the M sequence is 63 (for higher density DMRS), the following combination of polynomials can be used (the octal values ​​are 103, 147, 155 in sequence).

[0159] For: g(x) = x6 + x + 1

[0160]

[0161] For: g(x) = x6+x5+x2+x+1

[0162]

[0163] For: g(x) = x6+x5+x3+x2+1

[0164]

[0165] Other irreducible primitive polynomials are not excluded (octal values ​​133, 141, 163). The following initializations may be used but other initializations may not be excluded:

[0166] x(0)=0,x(1)=0,x(2)=0,x(3)=0,x(4)=0x(5)=1

[0167] The shift in two sequences can be defined using the following equation: Where s1, s2 are two sequences of length L. m0 and m1 are two shifts. N ranges from 0 to L-1.

[0168]

[0169] The combining functions m0 and m1 may be used to indicate the following: details for assisting channel decoding of NR-PBCH, which may include information about: polarization encoding and / or decoding; and beam ID.

[0170] In another option, parameters such as sequence polynomial and / or sequence shift can be a function of the cell ID. This can achieve orthogonal DMRS between different cells. If DMRS is not used to indicate the SS block ID but it is known before decoding NR-PBCH, these parameters can also be a function of the SS block ID.

[0171] For receiver processing, the following process can be used to detect information: the receiver can first use NR-PSS / NR-SSS to obtain timing and frequency; the receiver can receive OFDM symbols for NR-PBCH; DMRS RE allocation can be a function of cell ID and / or SS block ID and DMRS RE mapping can be obtained based on cell ID and / or SS block ID; DMRS sequence can be a function of cell ID and / or SS block ID, and a local copy of DMRS can be generated based on cell ID and / or SS block ID; local copy of DMRS can be used for channel estimation of NR-PBCH and demodulation / decoding of NR-PBCH.

[0172] NR-PBCH may use precoder cycling techniques to improve performance. In this case, the NR-PBCH reference signal(s), DMRS and / or SS may or may not be precoded using the same precoder cycling pattern as the NR-PBCH data. Assuming the same precoder is used, the precoder cycling may be applied in the frequency domain or the time domain. For frequency domain precoder cycling, some of the different options that may be used are described in detail below:

[0173] A single precoder for each NR-PBCH may be used. A single precoder may be applied to all RBs, e.g., 24 RBs, NR-PBCH data, and associated reference signals. DMRS may be generated from a single sequence (e.g., M, ZC, or golden sequence) because longer sequences may improve detection performance. DMRS may also be generated from two separate sequences separated in bandwidth.

[0174] A single precoder for each RBG may be used. The RBs and associated reference signals in the PBCH may be divided into multiple RB groups (RBGs) and a different precoder may be applied to each group. It should be noted that using different precoders may increase frequency diversity and thereby improve performance. In general, the RBG may vary from 1 to N, where N is the number of RBs in the NR-PBCH, in which case it may revert to the above options. The WTRU may be aware of this mode via signaling from the SS or as previously defined. A different sequence may be used for each RBG; however, it is important to adjust the number of DMRS and the length of the sequence to match each other. The sequence length should be an attempt to achieve the best correlation properties, and thus a particular sequence may cover more RBGs.

[0175] A single precoder may be used for each sub-RB. In an illustrative scenario, a precoder may be used for each RE, subcarrier, or OFDM symbol of the PBCH. A predefined precoder cycle pattern may be used for multiple REs, subcarriers, or OFDM symbols of the PBCH. One precoder per DMRS group may be used. A DMRS group may be defined as half an RB, a portion of an RB, or an RE group (REG). An association between DMRS REs and data REs in the PBCH may be defined. This may also improve frequency diversity.

[0176] The precoder loop can also be applied in the time domain. For the time domain precoder loop, some different options that can be used are described in detail here.

[0177] A single precoder may be applied for all NR-PBCH transmissions. In this case, a single precoder is applied to all PBCH data and reference signals. A different precoder may be applied for each mode (n) NR-PBCH transmission. In this case, a different precoder is applied to each NR-PBCH transmission of each mode (n). For example, when n=2, the following may be applied: NR-PBCH transmission (0) applies precoder (0), NR-PBCH transmission (1) applies precoder (1), NR-PBCH transmission (3) applies precoder (0), NR-PBCH transmission (4) applies precoder (1), and so on. The loop may enable different WTRUs to obtain enhanced performance for different NR-PBCH transmissions based on the unique spatial and frequency domain channel characteristics of each WTRU.

[0178] In each of the above cases, when more than one precoder is applied per NR-PBCH, a cyclic pattern may be selected to maximize spatial and frequency diversity. In an open-loop scheme, the cyclic pattern may be predetermined and may be selected, for example, based on the spatial properties of the precoder beams used for generation. Frequency domain characteristics may also be considered when selecting a precoder pattern to maximize diversity in the frequency domain.

[0179] In order to use NR-SS and self-contained DMRS for NR-PBCH transmission, an indication may be introduced to indicate to the WTRU whether the NR-SS and self-contained DMRS can be jointly used for channel estimation and coherent combination for NR-PBCH demodulation. A quasi-collocation (QCL) indicator may be introduced for initial access and NR-PBCH demodulation. When two signals are transmitted from two different antennas, the channels experienced by the two antennas may still have many large-scale properties in common. For example, the two signals may have the same or similar Doppler spread or shift, average delay, average delay spread, or average gain, so that the WTRU can use them to set parameters for channel estimation. However, when the two antennas are separated by a certain distance, the signals from the two antenna ports are different even in large-scale properties. The QCL indicator can be used to indicate the long-term channel properties of different antenna ports and different reference signals. For example, NR-SS and PBCH dedicated DMRS can be assumed to be QCL even if they are not in the same antenna port. In multiple transmission point (TRP) (multi-TRP) transmissions, NR-SS and PBCH dedicated DMRS may not be assumed to be QCL depending on whether they are in the same position. The QCL indicator may be indicated in the NR-SS signal. If message-based NR-SS is used, the synchronization payload may carry the QCL indicator. If sequence-based NR-SS is used, the QCL may be embedded in the NR-PSS or NR-SSS or a combination of the two. For example, different frequency and / or time relative offsets may be used to indicate the QCL. Different root indexes or cyclic shifts of the ZC sequence may be used to indicate the QCL. In addition, different combinations of X and Y components in the NR-PSS or NR-SSS may be used to indicate the QCL. Once the QCL is indicated to the WTRU, the WTRU may use the NR-PSS and / or NR-SSS as a combined reference signal together with the NR-PBCH dedicated DMRS for channel estimation. QCL-assisted initial access and NR-PBCH demodulation may be performed. Such QCL parameters may include, but are not limited to, Doppler spread or shift, channel average delay, channel average delay spread, channel average gain, beam correlation, and spatial correlation.

[0180] Fig.12 12 is a flow chart 1200 illustrating an example QCL indicator assisted or aided initial access procedure and NR-PBCH demodulation. Fig.12QCL indicator assisted NR-PBCH demodulation is shown. In this method, a QCL indicator is introduced to assist NR-PBCH demodulation. Depending on the value of QCL, different channel estimation configurations may be used for NR-PBCH demodulation. An exemplary method for QCL indicator assisted NR-PBCH demodulation is described in detail as follows. The WTRU may search 1202 for NR-SS signals and may detect 1204 NR-PSS and NR-SSS. The received QCL indicator and / or the value of the QCL indicator may be checked. If the QCL indicates a first configuration, such as configuration 1 1208, the WTRU may perform channel estimation 1210 using NR-SS and NR-PBCH-DMRS. If the QCL indicates a second configuration, such as configuration 2 1212, the WTRU may perform channel estimation 1214 using only NR-PBCH-DMRS. The WTRU may demodulate 1216 the NR-PBCH signal and the channel using the channel response estimated from configuration 1 1208 or configuration 2 1212.

[0181] Multi-antenna techniques may be used for NR-PBCH transmissions. For example, two-port space frequency block decoding (SFBC) and two-port precoder cycles may be used as multi-antenna techniques for NR-PBCH. For simplicity, a single antenna port may also be used. When more than one multi-antenna technique is used for NR-PBCH, information about the multi-antenna technique used for NR-PBCH may be indicated to the WTRU. Such an indication may be conveyed via the NP-PSS and / or NR-SSS to indicate one or more multi-antenna techniques or, in one embodiment, a MIMO scheme or method is used for NR-PBCH. Digital and analog beamforming techniques may be used. Hybrid digital and analog beamforming schemes may also be used.

[0182] Precoder cycling may be used as one of the techniques in the indicated multi-antenna technique. Open loop and semi-open loop methods may be used. Precoders using large delay cyclic delay diversity (CDD) and / or small delay CDD may be used. The precoder cycling pattern may be performed in time and / or frequency and may be predetermined or known to the WTRU. The NR-PBCH signal and the channels including self-contained DMRS within the NR-PBCH signal may use the same set of precoders and the same precoder cycling pattern may be applied. The gNB or TRP may perform digital beam scanning in time and / or frequency. Digital beamforming using precoder cycling or SFBC may be combined with analog beamforming and beam scanning for NR-PBCH.

[0183] An exemplary precoder cycle design for NR-PBCH is disclosed herein. The transmission of NR-PBCH may be based on two antenna ports with a precoder cycle. The transmission on the two antenna ports may have the same or different types of precoders and precoder schemes, for example, open loop (including large delay CDD or small delay CDD), semi-open loop, etc. may be used.

[0184] In the semi-open loop, the gNB or TRP can apply a precoder, which can be expressed as W = W 1 ·W 2 , where the wideband precoding matrix W 1 represents the long-term statistics and the (narrowband) precoding matrix W 2 Indicates the instantaneous channel condition. In the semi-open loop PBCH scheme, the long-term precoding matrix W 1 is fed back to the gNB from one or more WTRUs. This may in effect define a set of DFT beams to be used for that WTRU, indicating the approximate direction of the WTRU. It should be noted that this semi-open loop process may be applied to connected mode WTRUs. If the WTRU of a cell is located in a small area of ​​the gNB, a semi-open loop PBCH scheme may be applied, where W 1 It can be determined by the WTRU location. The gNB can then cycle the narrowband precoding matrix W 2 to determine the final precoder. The cyclic pattern can be in the time and / or frequency domain.

[0185] A digital precoder or an analog beamformer can be used for W 1 And digital beamformers can be used for W 2 One illustrative design may use analog beamforming (e.g., DFT-based W 1 ) and digital precoder W 2 . You can 2 Execute the precoder loop.

[0186] In another exemplary design, a digital W may be used. 1 (e.g. based on DFT) and W 2 . You can 2 or W 1 and W 2 Execute the precoder loop.

[0187] In another exemplary design, a digital W may be used. 1 (e.g. based on a precoder codebook) and W 2 . You can 2 or W 1 and W 2 A precoder cycle is performed. The precoder cycle can be performed for analog, digital beamforming or precoding, or a combination of both.

[0188] Fig.13 1300 is an example of using SS blocks associated with different precoders. In open-loop CDD transmission of PBCH, CDD coefficients can be applied at the subcarrier level or RB level. The cyclic pattern can be in the time and / or frequency domain. Since PBCH is broadcast repeatedly in a certain period of time, each PBCH message can be associated with a transmission mode of PBCH. Fig.13 An example of 4 SS blocks 1302-1308 is shown, each with identical content. Each SS block 1302-1408 may be associated with a different precoder 1310-1316 that directs the PBCH message in a different direction. In this example, SS1 1302 is associated with precoder 1 1310, SS2 1304 is associated with precoder 2 1312, SS3 1306 is associated with precoder 3 1314, and SS4 1308 is associated with precoder 1 1316. Each of the precoders 1-4 shown is for illustration purposes only. The quality of each of the selected precoders may be similar to or different from the conventional MIMO precoders of 4G. For example, a three-dimensional (3D) precoder may be used. Thus, the third dimension may take into account the WTRU altitude in the vertical direction. Other precoders may support highly parallel antenna technology. Existing MIMO precoding, such as 4G technology, may also be used. Existing codebooks may be used. In backward compatibility and / or flexible deployment scenarios, a new codebook may be added based on the existing codebook.

[0189] Fig.14 An example 1400 is shown where SS blocks are associated with different precoders, which change over different PBCH messages 1402, 1420, 1440, 1460. The association between the precoder and the SS block may be the same or may be different between different PBCH messages 1402, 1420, 1440, 1460. In one embodiment, the association may change. Fig.14An example is shown that illustrates how the association of precoders and SS blocks changes with PBCH messages 1402, 1420, 1440, 1460. Specifically, for a first PBCH message 1402, SS block i is associated with precoder i. Thus, precoder 1 1404 is associated with SS block 1 1406, precoder 2 1408 is associated with SS block 2 1410, precoder 3 1412 is associated with SS block 3 1414, and precoder 4 1416 is associated with SS block 4 1418. For a second PBCH message 1420, SS block i is associated with precoder i+1 mod 4; and so on. Thus, precoder 2 1422 is associated with SS block 1 1424, precoder 3 1426 is associated with SS block 2 1428, precoder 4 1430 is associated with SS block 3 1432, and precoder 1 1434 is associated with SS block 4 1436. In message 3 1440, precoder 3 1442 is associated with SS block 1 1444, precoder 4 1446 is associated with SS block 2 1448, precoder 1 1450 is associated with SS block 3 1452, and precoder 2 1454 is associated with SS block 4 1456. In message 1460, precoder 4 1462 is associated with SS block 1 1464, precoder 1 1466 is associated with SS block 2 1468, precoder 2 1470 is associated with SS block 3 1472, and precoder 3 1474 is associated with SS block 4 1476. Fig.13 As mentioned above, various precoding schemes can also be used Fig.14 For example, some precoder schemes may include a nonlinear precoding (NLP) scheme, Tomlinson-Harashima precoding, or vector perturbation. Other hybrid precoding schemes may include semi-dynamic or dynamic switching between linear precoding and NLP.

[0190] Fig.15 is a diagram of a transmit circuit 1500 configured for an illustrative combination of two-port cyclic delay diversity (CDD) and analog beamforming for diversity. Fig.14 The above-mentioned digital beam scanning scheme can be combined with analog beam scanning. Fig.15 An example of combining CDD with analog beamforming is shown. The aim is to exploit more diversity gain in space, frequency and time domains. Fig.15Two RF chains are shown: RF chain 1 1502 and RF chain 2 1504. RF chain 1 1502 circuitry may be configured to transmit 1510 at time t1 1506 using a first precoder. After a delay period, which may be implemented, for example, by a timer or clock circuit 1510, RF chain 2 1504 may send 1512 a second transmission using a second precoder. The second transmission may be sent at time t2 1508. The first transmission 1510 and the second transmission 1512 may overlap in time partially, fully, or not at all.

[0191] Fig.16 FIG. 16 is a diagram 1600 of a schematic combination of digital and analog beamforming shown in the time domain. Assume that there are n 1 modes, and in the analog beam scanning scheme there are n 2 A total of n modes can be supported for looping 1 ·n 2 Combination of. Fig.14 A schematic combination is shown in FIG. 1 =n 2 =2. In addition, only n 2 This type of beam scanning is used for analog beams while maintaining digital beam scanning. An alternative implementation of this approach is to use n in the time domain. 2 The beam scanning is used to simulate the beam scanning, while in the frequency domain n 1 This type of beam scanning is used for digital scanning, such as Fig.17 As shown. Fig.16 As shown, the same digital precoders 1602 and 1604 can be used for the first and second transmissions. For these same transmissions, two different analog beams 1606 and 1608 can be generated. For the third and fourth transmissions, second digital precoders 1610 and 1612 can be used. The second digital precoders 1610 and 1612 can be the same digital precoder. Analog beam 1 1614 and analog beam 2 1616 can be different analog beams used to achieve diversity.

[0192] Fig.17 is an illustration of a schematic combination of digital and analog beamforming in the time and frequency domains. In this embodiment, alternative analog beams are shown in the time domain and alternative digital beams are shown in the frequency domain. Fig.17 , in a first transmission in time, a second digital precoder 1702 is used in the same frequency as the first digital precoder 1704. At the same time, two identical analog beams 1706 and 1708 are transmitted. In a second transmission at another time, two different digital precoders 1710 and 1712 are used with two identical analog beams 1714 and 1716.

[0193] Fig.18 FIG. 1 is a diagram of a two-port space frequency block coding (SFBC) transmitter 1800 schematically combined with analog beamforming for transmit diversity. Fig.18 As shown in the circuit, the transmission of NR-PBCH can be based on one or more transmit diversity schemes, including a two-port SFBC scheme. In the high frequency band, for example, the transmission on each port can be associated with multiple antenna elements, and analog beamforming on each port can be used for further diversity gain. Fig.18 A schematic SFBC design combined with analog beamforming is shown to achieve further diversity gain. As shown, symbols S0 1802 and S1 1804 are sent on different subcarriers (subcarrier 1 1806 and subcarrier 2 1808) on antenna port 1 1810, while symbols -S1*1814 and S0*1812 are sent on different subcarriers (subcarrier 1 1806 and subcarrier 2 1808) on antenna port 2 1816. In this example, gain in the digital domain is achieved via the reverse of S1 1804, S0 1802 and S0*1814, -S1*1812. In this way, the bit stream provided to each of RF chain 1 1818 and RF chain 2 1820 is reversed. In the analog domain, each of RF chain 1 1818 and RF chain 2 1820 can use different beamforming techniques. If so, different beam shapes 1822 and 1824 may be transmitted to the receiver.

[0194] In one embodiment, the analog beamforming circuitry may adjust the beam direction and beam width for each of the antenna ports 1810 and 1816 in the SFBC scheme 1800. The control of the analog beamforming may depend on prior knowledge of the WTRU's geographical distribution. The WTRU may provide the WTRU's geographical distribution or beam position profile via uplink signaling or unlicensed access.

[0195] Communications for 5G NR at frequencies above 6 GHz will likely rely on highly directional transmission and reception. The first step for establishing a reliable link is the so-called initial access process, including cell search, PBCH transmission, and RACH process. The process associated with the current 4G LTE system can be used as a baseline. However, since LTE is limited to below 6 GHz, directional transmission and reception are not required and are not established to these initial access processes. Therefore, it is necessary to design a new initial access process that takes into account the additional complexity associated with a directional communication system. Each transmit and receive beam can cover a limited angular space and therefore a process for identifying beam pairs that can be used for communication needs to be established. This process can be performed via beam scanning at the transmission and / or reception point. Adding a beam scanning process can add significant complexity and power consumption, overhead, waiting time, etc. need to be considered.

[0196] A conventional beam scanning process may involve the TRP and the WTRU "testing" all combinations of beam pairs and selecting the beam pair that provides the best performance. The TRP transmitting a known sequence on a given beam may perform the "test" while the WTRU receives the given beam and measures the resulting SINR. This measurement may be repeated for all possible beam pairs and the beam pair that returns the maximum SINR value is selected. A framework for this type of process has been described in, e.g. Fig.19 The TRP described for 5G NR is defined at.

[0197] Fig.19 is a schematic TRP transmission structure 1900 that can be used for initial access. The transmission of the signal based on the initial access occurs at the synchronization signal burst time T ssb During 1902, every T p The SS cycle of 1904 seconds is repeated. In order to adapt to the beam scanning process, T ssb 1902 may consist of an integer number of OFDM symbols 1906 and 1908, where, for example, each OFDM symbol is spaced at an OFDM symbol time T sym 1910 is transmitted using different beams covering different angular regions. Using this basic framework, the WTRU can additionally scan the beam set and ultimately decide on the beam pair for subsequent communications. Thus, for any time T p seconds, possibly cycling through and testing multiple beams during the initial synchronization. This can provide significant performance improvements over performing additional tests after synchronization.

[0198] Designed for use Fig.19 A straightforward approach to the full beam scanning process of the framework defined in is to perform an exhaustive search of all available beam pairs at the TRP and WTRU, such as Fig. 20 shown.

[0199] Fig. 20An example single-stage exhaustive search beam scanning process 2000 is shown. Fig. 20 In the figure, each SS burst 2002, 2004, 2006 can be composed of N OFDM symbols, where each symbol transmits a single beam and the N beams cover the entire angular area of ​​​​TRP2008. As also shown in the figure, the WTRU 2010 receives from a single beam throughout the SS burst, so a full beam scan requires M SS bursts 2012, 2014, 2016 to test all possible beam pairs. It should be noted that in order to take into account signal blocking at the WTRU2010, it is possible to have more than one receiving array. In one example, the array can be on each side of a rectangular device. In this case, each array supports M beams, which is the total number of WTRU beams, so the total number of SS bursts used for full beam scanning is 4M. As described, system overhead, access latency, and total power consumption are issues for the initial access process. The present application solves these problems regarding overhead, latency, and power consumption. In terms of overhead, each OFDM symbol used for synchronization can not be used for other purposes, such as data transmission. This is a problem for large N. The duration of the entire process can also be considered as an additional overhead relative to the reduced time that can be used for communication. Regarding latency, one thing that provides an enhanced user experience is the ability to quickly establish a communication link. In this case, a large M that is further coupled with more than one array to combat blocking can significantly increase the access time. Power consumption is another issue, and in general, low power consumption is desired. Low power consumption is especially desired in the WTRU because the WTRU is typically a battery-powered device. Each beam pair measurement requires WTRU power, so limiting the number of beam pair measurements can be used to reduce power consumption.

[0200] Fig.21 is an example of multi-stage WTRU hierarchical beam scanning 2100. Fig. 20 An alternative to the single-stage exhaustive beam scanning method shown in is a multi-stage hierarchical method 2100. The search may start with a wide beam covering a relatively large angular area in the first stage and then gradually reduce the beam width and angular search space used in subsequent stages. This gradual reduction may be applied only at the TRP, only at the WTRU, or at both the TRP and the WTRU. For illustration purposes, Fig.21An example of a three-stage hierarchical WTRU beam scanning is shown. In this example, the WTRU 2102 uses four arrays, each of which uses 12 beams to cover its angular area. From a latency perspective, an exhaustive beam scanning process may require 4*12=48 SS bursts. The three-stage 2104-2108 process shown may require only 4+4+3=11 SS bursts 2110-2120. In addition, from a power consumption perspective, the exhaustive beam scanning process requires 48N measurements, but the current three-stage process only needs to perform 11N measurements. In both cases, approximately 77% is saved. The following disclosure describes the process in more detail. For all stages 2104-2108, the TRP 2122 transmits N beams per SS burst 2110-2120 on N OFDM symbols. On the other hand, the WTRU 2102 performs different operations over time. In the first stage 2104, the WTRU 2102 receives using a single quasi-omni beam per SS burst per array 2124. In the second stage 2106, the WTRU 2102 receives from the four wide beams 2126 from the array that yielded the maximum SINR from stage 1 2104. In the third stage 2108, the WTRU 2102 receives from the three narrow beams 2128 that are partially contained within the wide beam that yielded the maximum SINR from stage 2 2106.

[0201] Fig. 22 Another example of using multi-stage TRP graded beam scanning is shown. It should be noted that Fig. 22Also shown are implementations where the WTRU may be hierarchical whereby multi-stage TRP / WTRU hierarchical beam scanning is possible. For these cases, the schematic process is as follows. In the first stage 2202, the TRP 2204 transmits from four wide beams for each SS burst 2208-2210 on 4 OFDM symbols. At the same time, in the first stage 2202, the WTRU 2206 receives from M beams using a single beam per SS burst 2208-2210. In the second stage 2212, the TRP transmits from N narrow beams per SS burst 2214-2216 on N OFDM symbols. In the second stage 2212, the WTRU 2206 has three options 2214-2218. In the first option 2214, the WTRU 2206 receives from the M beams using one beam per SS burst, but the WTRU 2206 may measure only the TRP narrow beams that are partially contained within the TRP wide beam detected in the first stage 2202. In the second option 2216, to further reduce power consumption, the WTRU 2206 may receive from only one WTRU beam that produced the maximum SINR measurement from the first stage 2202. In the third option 2218, to increase the SINR from the directional gain, the WTRU may use a hierarchical approach and receive from a set of narrow beams that are partially contained within the detected WTRU 2206 wide beam from the first stage 2202.

[0202] For the first two options 2214-2216, if it is assumed that there are three narrow TRP beams per wide beam, the number of beam pair measurements required is 4M+3M for option 1 and 4M+3 for option 2. This is compared to the multiplication of the number of measurements required in the single-stage exhaustive process, where the number of measurements required is 12M. This yields approximately 42% and 60% savings, respectively. The third option 2218 combines TRP 2204 and WTRU 2206 hierarchical beam scanning. In this case, the number of measurements required is 4M+3M. 窄 In this case, if we assume that M = 4 and M 窄 =3, then the number of measurements required is 25. It should be noted that this case uses a narrower beam in stage 2 2212 and thus additional array gain associated with narrow beams can be seen compared to option 1 2214 and option 2 2216. A single stage exhaustive comparison for this option requires 12*12=144 measurements, thus this third option 2218 results in a savings of approximately 83%.

[0203] Another aspect of the initial access procedure to consider is the amount of interference observed at the WTRU from other TRPs. The multi-stage procedure, which is primarily intended to reduce latency, power consumption, and overhead, can be further modified to also address interference issues. The main idea behind reducing interference is to exploit the use of multiple stages whereby information from earlier stages can be used in later stages to potentially "turn off" by filtering out certain TRP beams.

[0204] Fig.23 An example of this approach, referred to as selective beam scanning, is shown in conjunction with a multi-stage TRP / WTRU hierarchical beam scanning process. A general description of this process is detailed below. In the first stage 2302, the TRP 2304 w OFDM symbols for each SS burst 2308-2310 from N w In the same phase 2302, the WTRU 2312 transmits from M using one beam per SS burst. w In the second stage 2316, TRP2304 receives only the selected LN N N narrow beams 2318 are transmitted, where L is the total number of wide beams detected from all WTRUs and N N is the number of narrow beams within each wide beam. TRP 2304 may be transmitted repeatedly for each SS burst 2318-2322.

[0205] The TRP may know or obtain information about the detected wide beam from the WTRU directly via uplink or indirectly from the anchor TRP to which the WTRU is already attached using the beam pair from the first stage. The WTRU may obtain information about the detected wide beam from the N spatially contained within the WTRU wide beam detected in the first stage. N A narrow beam is used for reception.

[0206] Fig.23 The process shown combines TRP hierarchical beam scanning, WTRU hierarchical beam scanning, and TRP selective beam scanning to minimize SINR while reducing power consumption, latency, and overhead. With respect to SIRN improvement, since interference from "other" TRPs in the WTRU is reduced, it should be noted that this approach has advantages when the WTRU density is low and / or the WTRUs are not evenly distributed. For example, consider a situation where all WTRUs are collected in a certain geographic area within the coverage area of ​​a TRP. This could be the case, for example, when watching a sporting event or a concert. In this case, each WTRU can access the TRP using a similarly directional TRP beam, thereby eliminating the need for the TRP to transmit on certain beams once the TRP is aware of this situation. It should also be noted that in addition to reducing interference, this embodiment can also provide power consumption savings at the TRP.

[0207] The advantages of the above process can also be seen empirically through system simulation. Fig.24 SINR results 2400 from four different beam scanning processes are shown, three of which are repeated for non-uniform WTRU distribution to show the TRP selective scanning performance gain. The results of the simulation process are summarized as follows. One result shown includes a single-stage beam scanning 2402. This single-stage beam scanning can be a single-stage simulation run for uniform WTRU distribution only, because a second stage is required to activate TRP selective beam scanning. The performance of the single-stage beam scanning 2402 is almost the same as the two-stage TRP selective beam scanning process for uniform WTRU distribution. Therefore, they are both labeled 2402.

[0208] There is no hierarchical scanning in the two-stage TRP selective beam scanning 2402, so when the WTRUs are uniformly distributed, the performance is almost the same as the above single-stage process as described above. When the WTRUs are non-uniformly distributed, SINR gains based on interference level reduction can be achieved. For comparison, the case of two-stage selective non-uniform 2408 is shown.

[0209] Another result shown is two-stage TRP grading selective beam scanning 2404. There is an overall gain with respect to the above process based on the TRP grading approach using narrower beams in the second stage. There is also a gain based on the interference reduction from TRPs being "turned off" when the WTRUs are again non-uniformly distributed. For comparison, the case of two-stage selective TRP grading non-uniform 2410 is shown.

[0210] Another result is the two-stage TRP / WTRU hierarchical selective beam scanning 2406. There is additional gain based on adding WTRU hierarchical approach using narrower beams again in the second stage. There is also gain based on interference reduction from TRP beams being "turned off" when the WTRUs are again non-uniformly distributed. For comparison, the two-stage selective non-uniform 2412 case is shown.

[0211] Fig.25 Shows Fig.19 An alternative form 2500 of the TRP transmission structure shown in FIG. Fig.25 As shown, the defined SS bursts 2502-2508 and SS period 2510 are still maintained. In this case, a single SS burst 2502-2508 that still occupies more than one OFDM symbol is considered to be transmitted in a single beam direction. The SS bursts 2502-2508 shown above are transmitted in the SS period T P 2510 per ton PThe WTRU may perform a full beam scan in this case, which may take a minimum of N SS bursts, depending on how the WTRU beam scan is implemented.

[0212] use Fig.25 The straightforward full-beam scanning process of the framework defined in can be performed by performing an exhaustive search over all available TRP and WTRU beam pairs. Fig.26 The process 2600 shown is similar to Fig. 20 The process is shown, except that the roles of the WTRU and TRP are swapped regarding the beam scanning sequence. The TRP 2602 transmits one of the N beam directions during the SS burst 2604-2608, and the WTRU 2610 sequentially passes through all M beam directions during each SS burst 2604-2608. Using this process, a full beam scan needs to be completed N SS burst times.

[0213] The general observation can be applied to the cell center WTRU. In general, it is possible that the cell center WTRU may require less antenna gain than the cell edge WTRU. This may be true during and before the initial access procedure is completed and in order to achieve successful data transmission. In addition, it should be noted that multiple RF chain transmissions are more feasible at the TRP than at the WTRU due to things like cost and power. In view of this, it may be possible to base the transmission on the TRP. Fig.25 The transmission structure shown implements a beam scanning process that can reduce access latency and save processing power in cell-center WTRUs while allowing cell-edge WTRUs to gain access. Fig. 27 The process is shown.

[0214] Fig. 27 is an example of a single-stage multi-RF chain TRP beam scan 2700. Fig. 27 In the example shown, two RF chains 2702-2704 are used for the initial access process at the TRP. The first RF chain 2702 uses N N N narrow beams 2706 cover the TRP service area, while the second RF chain 2704 uses N N Wide beams 2708 cover the same TRP service area, where N W <N N One or more WTRUs 2710 may then receive from all M beams during each SS burst 2712-2722. This configuration enables a cell center WTRU to complete the initial access procedure with reduced latency compared to a cell edge WTRU. This process is described in more detail below. The first TRP RF chain 2702 transmits N SS bursts 2712-2716.N One of the beams. The beam scanning period is N N bursts. The second RF chain 2704 transmits one of the N W beams per SS burst 2718 - 2722. The beam scanning period is N W bursts. In one embodiment, N W < N N. . RF chains 1 and 2 may use the same, partially overlapping, or completely different circuitry. Regarding the WTRU side, the WTRU cycles through all M beams during each SS burst 2724 - 2730. The cell - center WTRU may decide on a beam pair after N W SS bursts. The cell - edge WTRU may decide on a beam pair after N N SS bursts. The WTRU may decide to search for wide or narrow TRP beams based on various criteria (e.g., information from an anchor TRP, initial signal power measurements, etc.).

[0215] MIMO and multi - beam transmission may be implemented for initial access and, in one embodiment, license - free transmission may be implemented for beamforming of MIMO and PBCH and subsequent DL transmissions. At least one set of beamforming parameters may be provided, determined, configured, and / or known according to a specification. The configuration may be provided and / or transmitted, for example, by the gNB via signaling such as broadcast or dedicated signaling. The WTRU may receive the configuration.

[0216] Here, the precoder may be used as a non - limiting example of a beamforming parameter. Some other examples include antenna ports, such as CSI - RS ports, sets of antenna ports, beam IDs, sets of beam IDs, etc. In the embodiments and examples described herein, any other beamforming parameter may be substituted for the precoder and still be consistent with one or more of the embodiments herein.

[0217] The WTRU may select at least one precoder from a set of precoders, e.g., W 1 or w 2 . The WTRU may select a first precoder from a first set of precoders. The WTRU may select a second precoder from a second set of precoders. The first and second sets may be the same or different. The WTRU may select a precoder that may be a preferred or recommended precoder. The WTRU may signal or indicate at least one precoder it has selected, e.g., send or indicate it to the gNB.

[0218] The WTRU may select a precoder for a broadcast transmission, such as for a broadcast channel, such as PBCH. The WTRU may use a first precoder for a first reception of a broadcast channel. The WTRU may determine or may know the first precoder prior to use. The first precoder may be a default precoder known to the WTRU.

[0219] The WTRU may determine a first precoder from at least one synchronization channel, for example, based on at least one of: a time and / or frequency position, such as a relative position of first and second synchronization channels; a payload associated with the synchronization channel; or a synchronization channel sequence.

[0220] The WTRU may use a first precoder, for example until instructed to use another precoder. The WTRU may indicate a precoder, for example a preferred precoder, for example for a broadcast channel. The WTRU may indicate a precoder to the gNB. The WTRU may indicate a precoder in an unlicensed access that the WTRU may perform, for example before or without establishing an RRC connection. The WTRU may indicate a precoder in an unlicensed access that the WTRU may perform, for example before or without establishing an RRC connection with the gNB.

[0221] Unlicensed access may be a transmission using resources in time and / or frequency without a license (e.g., without an explicit license). Unlicensed access may be or include random access, such as a 2-step or 4-step random access. Unlicensed access may be or include a 1-step transmission or a 1-step random access, such as message 1 or only message 1 of a random access procedure.

[0222] The resources and / or preambles that may be used for unlicensed access may be configured via a broadcast channel or system information. Unlicensed access may include transmission of at least one of: a preamble, control information, and / or a data payload. The WTRU may use the preamble, control information, and / or data payload to indicate a selected precoder. The WTRU may expect a response or acknowledgement for unlicensed access and / or information communicated by the unlicensed access. Alternatively, the WTRU may not expect a response or acknowledgement for an unlicensed access (e.g., an unlicensed access that may be used to indicate beamforming parameters).

[0223] The gNB may receive a precoder indication, for example, from a WTRU. The gNB may receive the precoder indication via unlicensed access. The gNB may receive a precoder indication for a broadcast channel. The gNB may use a precoder for semi-open-loop MIMO applied to the broadcast channel.

[0224] The gNB may receive a first precoder indication from a first WTRU and a second precoder indication from a second WTRU. The gNB may determine a precoder to be used, for example, for a broadcast channel based on the first precoder indication and the second precoder indication. The gNB may use the determined precoder, for example, for transmission of the broadcast channel.

[0225] In an example, the determined precoder may be a compromise between a first precoder and a second precoder. In another example, the first precoder may be used at times and the second precoder may be used at other times. For example, the gNB may cycle through a set of indicated precoders that it receives from a set of WTRUs that may provide indications for the same beam or set of beams or provide indications from the same or similar directions. The gNB may alternate between the first and second indicated precoders.

[0226] The gNB may indicate beamforming parameters, such as precoder, in response to unlicensed access. The response may be via DL Control Information (DCI) or a DL data channel, which may have an associated DCI that may indicate the resources of the DL data channel. The DCI may use a common RNTI. The WTRU may monitor the common RNTI to receive DCI and / or DL ​​data.

[0227] A synchronization channel or a set of synchronization channels may be used to indicate a precoder that may be used for a broadcast channel. The gNB may modify a synchronization channel or a set of synchronization channels when it modifies the precoder used for a broadcast channel. The modification may be to the synchronization channel sequence, time and / or frequency position, such as using the relative position of a first and a second synchronization channel, and / or the payload associated with the synchronization channel.

[0228] The first broadcast channel may be used to indicate a precoder and / or precoder cycling pattern that may be used for the second broadcast channel. The indication may be provided in a payload carried by the first broadcast channel.

[0229] The WTRU may use the indicated precoder and / or precoder cycling pattern for reception of a channel (e.g., a secondary broadcast channel). The indication may be provided by the gNB. The WTRU may use the selected precoder for reception of a channel (e.g., a broadcast channel or a secondary broadcast channel). The selected precoder or precoder cycling pattern may be one indicated by the WTRU, e.g., in unlicensed access. The selected precoder or precoder cycling pattern may be one indicated by the WTRU, e.g., to the gNB.

[0230] In an example, the WTRU may receive a channel such as a broadcast channel using a first precoder. The WTRU may receive the channel using a second precoder, for example, when reception of the first precoder is unsuccessful or to receive a secondary broadcast channel.

[0231] The first precoder or the second precoder may be a precoder selected by the WTRU. The WTRU may use the first or second precoder after indicating the first or second precoder (e.g., to the gNB and / or in unlicensed access). The second or first precoder may be an initial precoder, a default precoder, a configured precoder, or an indicated precoder. The WTRU may use unlicensed transmission to feedback at least one of the following: a precoder, e.g., a w 1 ; Precoder, such as W for short-term statistics 2 or instantaneous channel conditions; simulated beamformer, such as beam ID or beam ID set; beam to link or beam to link set; antenna port or virtual antenna port, such as CSI-RS port or CSI-RS port set; beam position profile (one or more); ACK / NACK in response to beam (one or more); WTRU beam correspondence or reciprocity; and the like.

[0232] In the case of a time duplex sequence DMRS, a DMRS sequence of length 72 can be generated. The sequence can be mapped to 72 RE DMRS of the first OFDM symbol and then copied to the second OFDM symbol. If QPSK modulation is used, a length 144 sequence is generated, converted into 72 QPSK symbols and mapped to all REs of each OFDM symbol. If BPSK modulation is used, a length 72 sequence can be generated and mapped to all REs of each OFDM symbol. In this configuration, since only one sequence is generated, it can carry an SS block time index (SBTI). The terms SS block ID, SS block index, and SS block time index can be used interchangeably. Different ways of SBIT indication are disclosed. Since each DMRS RE for the second OFDM symbol is repeated in time, the remaining CFO estimate can be performed and corrected. However, the sequence of reduced length can reduce the detection performance of SBTI. It is difficult to perform pre-balancing of these symbols outside the NR-PSS / NR-SSS bandwidth similar to using channel estimation. This can cause the receiver to perform incoherent detection and thereby reduce performance.

[0233] For example, in a frequency duplex sequence DMRS configuration, a DMRS sequence of length 72 (S(1:72)) can be generated. This then maps the center 12 RBs onto two OFDM symbols of the NR-PBCH. The same sequence is also replicated to the remaining 12 RBs (outside the SS bandwidth). This can be done in a number of different ways.

[0234] Fig.28 and 29 Frequency repetition or frequency swap repetition 2800, 2900 is shown. Fig.28In , on PBCH1, bits S(19:36) 2802-2804 are found twice. This is also true for bits S(1:18) 2808-2810. On PBCH2, a similar ordering can be found. In this example, bits S(55:72) 2814-2816 are repeated twice along with bits S(37:54) 2818-2820. Fig.28 Repetition in the frequency domain rather than the time domain is provided.

[0235] Fig.29 is another example of frequency repetition 2900. Fig.29 , PBCH1 2902 conveys bit S(19:36) 2906 between bit S(1:18) 2904 and bit S(1:18) 2908. Adjacent bit S(1:18) 2908 is another instance of bit S(19:36) 1910. On PBCH2 2912, bit S(55:72) 2916 is found between bit S(37:54) 2914 and bit S(37:54) 2918. Adjacent bit S(37:54) 2918 is bit S(55:72) 2920. Frequency swapping can generate more diversity. It is also possible to perform frequency and / or time swapping repetitions in different ways.

[0236] Fig.30 and 31 Some exemplary embodiments 3000, 3100 are shown. Fig.30 In the example, on PBCH1 3002, bit S(19:36) 3006 is located between bit S(55:72) 3004 and bit S(1:18) 3008. Adjacent to bit S(1:18) 3008 is bit S(37:54) 3010. PBCH2 3012 consists of bit S(55:72) 3016 located between bit S(19:36) 3014 and bit S(37:54) 3018. Bit S(37:54) 3018 is adjacent to bit S(1:18) 3020. In this way, redundancy is provided in the time domain and frequency interleaving is applied.

[0237] Fig.31 is similar to Fig.30 Example. Fig.31In PBCH1 3102, bit S(19:36) 3106 is located between bit S(37:54) 3104 and bit S(1:18) 3108. Adjacent to bit S(1:18) 3108 is bit S(55:72) 3110. PBCH2 3112 consists of bit S(55:72) 3116 located between bit S(1:18) 3014 and bit S(37:54) 3118. Bit S(37:54) 3118 is adjacent to bit S(19:36) 3120. Fig.31 The bit ordering of Fig.30 On the contrary, Fig.30 The higher numbered bits 3004 and 3014 are moved to Fig.31 The opposite frequency ends 3110, 3120. Fig.30 The bits S(37:54)3002 and S(1:18)3020 are Fig.31 S(37:54)3104 and S(1:18)3114 are similar.

[0238] A potential feature of these configurations is that only the center REs need to be decoded to find the SBTI. These configurations can reduce the SBTI detection complexity if the channel conditions are known to be good based on NR-PSS / NR-SSS detection. In this configuration, NR-PSS / NR-SSS can be used for pre-balancing of coherent detection of sequences carried on the center RBs. For RBs outside the NR-SS bandwidth, non-coherent detection must be performed. They can be combined with coherent detection of the center RBs.

[0239] NR-PSS and NR-SSS may occupy only the center N REs, e.g. N=127 REs, instead of all 144 REs for 12 RBs. Therefore, a good channel estimation may be performed for only 31 REs in one OFDM symbol or for a total of 62 REs in two OFDM symbols. The channel estimation inference may not be performed very well. Furthermore, the method may not allow subcarriers to repeat in time and thus residual CFO estimation is not possible. Therefore, a modified method may be used additionally or in combination.

[0240] In one embodiment, a DMRS sequence of length 62 may be mapped to the center 12 RBs on the subcarriers overlapping with the NR-PSS / NR-SSS, and the repeated sequence may be mapped to the remaining 12 RBs. Fig.32 A sequence of length 62 is shown repeating in frequency. A schematic diagram of PBCH1 3202 and PBCH2 is shown. The areas marked with x3204-3216 are areas where payload can be transmitted. Fig.32The shaded area represents the sequence of REs and PBCH DMRS, but not the payload. DMRS subcarriers 3204-3216 are filled with symbols repeated in the second OFDM symbol of NR-PBCH on DMRS REs. Due to the asymmetry, in each OFDM symbol, the higher band (outside the SS bandwidth) has 2 such REs and the lower band (outside the SS bandwidth) has 3 such REs. They can be used for CFO compensation and channel estimation. In the area outside the NR-SS bandwidth, these subcarriers are more evenly distributed. This length 62 scheme can also have different configurations, such as time and frequency swapping, such as Figure 28-31 As shown in Fig.32 As shown, the shaded area 3218-3236 may carry the sequence for the PBCH DMRS. PBCH2 includes payload elements 3240-3252 and bits for DMRS 3254-3270. In this way, the payload elements may be interleaved with the DMRS.

[0241] All the above schemes only have a single sequence containing information about the SBTI. Therefore, channel estimation using these DMRS is only possible after decoding the SBTI. Therefore, in order to coherently decode the SBTI, only information within the SS bandwidth can be used. To overcome this problem, another design is disclosed. In this design, two sequences are used. The first sequence is mapped on the DMRS RE of the first OFDM symbol of the NR-PBCH. The second sequence is mapped on the DMRS RE of the second OFDM symbol of the NR-PBCH.

[0242] A first sequence is generated using the cell ID. For convenience, this is called the reference DMRS. The cell ID can be determined from the detection of the NR-PSS / NR-SSS. Using the cell ID, the first sequence can be determined. Knowledge of the sequence can be used to perform channel estimation on these REs. These channel estimates can be used to pre-balance the DMRS REs or subcarriers. The second sequence depends on only the SBTI or on both the cell ID and the SBTI. Since the sequence is used to indicate the SBTI, the term indicating DMRS used here is used to refer to the sequence. After coherent detection of the second sequence, the SBTI can be decoded. The sequence can be a function of multiple numbers of variables.

[0243] In another variation of a similar concept, a known base sequence can be generated. The base is modified using the cell ID to generate a sequence for the reference DMRS. The sequence can also be modified using the SBTI to generate a sequence for the indication DMRS. The reference DMRS is used for pre-balancing and coherent estimation of the indication DMRS and thereby detecting the SBTI.

[0244] These modifications according to SBTI can be performed using some of the following methods: different initialization of the linear feedback shift register (LFSR) for the M-sequence of the gold code; frequency or cyclic shift of the M-sequence of the gold code; frequency or cyclic shift of the gold sequence; cyclic shift; and performing scrambling on the initial sequence.

[0245] Once NR-PSS and NR-SSS are detected, they can be used as known sequences for channel estimation and pre-balancing of the center RB, and it is possible to use reference DMRS only on RBs (or subcarriers) that are not occupied by NR-PSS / NR-SSS. Thus, the indication DMRS is mapped to the first and second OFDM symbols of the NR-PBCH for the bandwidth overlapping with NR-PSS and NR-SSS. This can increase the length of the sequence used to indicate the DMRS and can improve the performance of the indication DMRS.

[0246] In the above design, the first sequence is mapped to the first OFDM symbol of NR-PPBCH, and the second sequence is mapped to the second OFDM symbol. It is also possible to alternate the two sequences within one OFDM symbol. The sequences are thus mapped to the DMRS REs of alternating OFDM symbols of NR-PBCH. This can improve the channel estimation performance using one of the sequences. It also improves the diversity of the second sequence and thereby improves the detection performance of SBTI. Fig.33 This pattern is illustrated in Figure 2, which shows the NR-PBCH DMRS distribution for two sequences of a comb pattern.

[0247] Fig.33 3300 is an example of NR-PBCH DMRS distribution for two sequences of comb pattern. Fig.33 In the embodiment, r1 3304-3310 shows REs where reference DMRS is mapped and r2 3312-3316 shows REs where indication DMRS is mapped. With reference to NR-PBCH1 3302, r1 3304-3310 are scattered between r2 3312-3316. With reference to NR-PBCH2 3318, r1 3320-3324 are scattered between r2 3326-3332.

[0248] This comb pattern may be used to transmit both reference DMRS and indication DMRS. In one design, the reference DMRS sequence may be generated using only the cell ID. This may then be modified using SBIT to generate the indication DMRS sequence.

[0249] In another option, a known base sequence is generated. The sequence is modified using the cell ID to generate a sequence for reference DMRS. The base sequence is also modified using the SBTI to generate a sequence for indicating DMRS.

[0250] Like the simple mode case, different modifications can be performed based on the SBTI using one or more of the following: different initialization of the linear feedback shift register (LFSR) for the M-sequence of the gold code; frequency or cyclic shift of the M-sequence of the gold code; frequency or cyclic shift of the gold sequence; cyclic shift; and / or scrambling on one or more of the original sequences.

[0251] Like the simple mode case, NR-PSS and NR-SSS can be used for channel estimation and pre-balancing of the center RB. The reference DMRS can be used only on RBs (or subcarriers) that are not occupied by NR-PSS / NR-SSS. The DMRS is thereby indicated to be mapped on the first and second OFDM symbols of the NR-PBCH for the bandwidth overlapping with the NR-PSS and NR-SSS. This can increase the length of the sequence used to indicate the DMRS and thus can improve the performance of indicating the DMRS.

[0252] A short LFSR golden sequence can be implemented using a shift register. Thus, shift registers of different lengths can be used to generate the golden sequence. For example, if a short length LSFR of length 7 is used:

[0253] c(n)=(x 1 (n)+x 2 (n))mod2

[0254] x 1 (n+7)=(x 1 (n+4)+x 1 (n))mod2

[0255] x 2 (n+7)=(x 2 (n+1)+x 2 (n))mod2

[0256] One or both m-sequences may be initialized with states x(0) = 0, x(1) = 0, x(2) = 0, ..., x(5) = 0 x(6) = 1. If only one LSFR is initialized to

[00001] , the other LFSR may be initialized using the SS block time index or the cell ID or a combination of both.

[0257] Additionally or in combination, long LFSR golden sequences may be used.Long LFSR golden sequences may also be generated via longer shift registers and shifting (Nc) while selecting the portion of the output that may be used to select the golden sequence of the desired length.

[0258] c(n)=(x 1 (n+N C )+x 2 (n+NC ))mod2

[0259] x 1 (n+31)=(x 1 (n+3)+x 1 (n))mod2

[0260] x 2 (n+31)=(x 2 (n+3)+x 2 (n+2)+x 2 (n+1)+x 2 (n))mod2

[0261] Nc can be defined as an integer. For example, N C =1600.

[0262] Very long LFSR golden sequences, for example length 64 can also be generated by longer shift registers and shifting (Nc), while selecting this output can be used to select the portion of the golden sequence of the desired length.

[0263] c(n)=(x 1 (n+N C )+x 2 (n+N C ))mod2

[0264] x 1 (n+63)=(x 1 (n+1)+x 1 (n))mod2

[0265] x 2 (n+63)=(x 2 (n+38)+x 2 (n+13)+x 2 (n+1)+x 2 (n))mod2

[0266] In this example, Here, N c can be a much larger integer and can be found empirically to find good correlation sequences.

[0267] Any of the above sequences may have scrambling applied prior to modulation (BPSK / QPSK). The scrambling code may be generated from a LFSR of similar length.

[0268] After modulation (BPSK / QPSK) a cyclic shift can be applied to any golden sequence.

[0269] The cyclic shift can be of the form Where m = 0, 1, ... M-1 and i is the shift index. In this example, seq is the original modulation sequence and seq cs is a sequence with cyclic shifts.

[0270] Modulation is used for the sequences and all the above sequences can be BPSK or QPSK modulated.

[0271] Using BPSK, r(m) = (1-2·c(m))

[0272] Using QPSK, every two bits can be combined into one symbol.

[0273] interval The bits of distance can be combined into a symbol,

[0274] In an embodiment, NR-PBCH DMRS time block ID indication / detection may be implemented. Different initializations of the M-sequence LFSR may be performed.

[0275] For example, consider the golden code defined by:

[0276] c(n)=(x 1 (n)+x 2 (n))mod2

[0277] x 1 (n+7)=(x 1 (n+4)+x 1 (n))mod2

[0278] x 2 (n+7)=(x 2 (n+1)+x 2 (n))mod2

[0279] x1 is the first m-sequence and x2 is the second m-sequence for generating the gold code. The LFSR for generating one or two m-sequences x1, x2 of the gold code can be initialized using SBTI or cell ID or a combination of the two or even more variables (e.g., RNTI, slot number, cell ID, half frame).

[0280] Different examples of these initializations are listed below:

[0281] Option 1: Option 2: Where x is a known integer. Option 3: (x is an integer <L lfsr-1-10), 10 bits are used to indicate Option 4: Option 5 may be a more general option, option 5: where x1 to x5 can be empirically determined to have the best correlation properties. More options are also possible.

[0282] It is also possible to generate two different golden sequences using two different initializations.For example, a first shift to obtain a reference DMRS may be used for pre-balancing and another shift to obtain an indication DMRS may be used to indicate SBTI.

[0283] If only one sequence is used, partially coherent / partially incoherent detection can be performed.Different hypotheses of the golden sequence are generated at the receiver (using different initializations of the M sequence) to detect SBTI.

[0284] Frequency or cyclic shifts of the individual M sequences may be applied.

[0285]

[0286] The cell ID and / or SBTI jointly or separately determine the cyclic shift values ​​m0, m1. Knowing the relationship between the cell ID SBTI and m0, m1, and knowing the cell ID from the detection of the PSS / SSS, a hypothesis can be generated for the SBTI, and it can be used to detect which SBTI is indicated in the gold code.

[0287] It is possible to use two different cyclic shifts in the M sequence to generate two different golden sequences. The first shift results in a reference DMRS for pre-balancing and the other shift results in an indication DMRS for indicating STBI. If only one sequence is used, partially coherent / partially incoherent detection can be performed. Different hypotheses are generated at the receiver (e.g., using different frequency shifts of a separate M sequence) to detect STBI.

[0288] The frequency or cyclic shift of the golden sequence can be:

[0289] r=c((n+m0)modL)

[0290] c(n)=(x 1 (n)+x 2 (n))mod2

[0291] x 1 (n+7)=(x 1 (n+4)+x 1 (n))mod2

[0292] x 2 (n+7)=(x 2 (n+1)+x2 (n))mod2

[0293] The cell ID and / or SBTI can determine the cyclic shift value m0. Knowing the relationship between the cell ID SBTI and m0, and knowing the cell ID from the detection of the PSS / SSS, a hypothesis can be generated for the SBTI. And detecting which SBTI the golden code indicates. This is especially the case of 'cyclic shift of separate M sequences', where both sequences have the same shift (m0=m1).

[0294] It is possible to generate two different golden sequences using two different cyclic shifts in frequency: one for pre-balancing and another for indicating SBTI.

[0295] If only one sequence is used, partially coherent / partially incoherent detection can be performed.Different hypotheses can be generated, for example at the receiver, using different frequency shifts of the golden sequence to detect STBI.

[0296] Fig.34 is an example 3400 of using cyclically shifted DMRS and STBI indication. Fig.35 is an example 3500 of using cyclically shifted DMRS and STBI indication in a comb pattern. Cyclic shift techniques can be used and some examples are shown here. The first sequence (reference DMRS) is generated using the following process: Initial value c init Can be used to generate length The demodulation reference signal r of the first OFDM symbol used for NR-PBCH 1 pbch (m) is QPSK modulated and is defined by:

[0297]

[0298] In the above equation, represents the bandwidth assigned in the resource block of the NR-PBCH transmission. A pseudo-random sequence c(i) may be defined according to one or more embodiments described herein.

[0299] The second sequence (indicative of DMRS) is generated using the following process: A demodulation reference signal for the second OFDM symbol of the NR-PBCH is generated using a cyclic shift of the sequence of the first symbol.

[0300]

[0301] In this example, k=2 or 3 depends on how many bits need to be indicated for the SS block timing index. These sequences can be mapped in a simple pattern of comb patterns. Due to the cyclic nature of the cyclic shift, every 8th tone of the reference DMRS and the indication DMRS is the same. This property is used to estimate CFO at the receiver and the cyclic shift can be used to estimate SBTI.

[0302] CFO estimation can be performed using:

[0303] Where fc is the carrier frequency and ΔnOFDM=2 (the distance between two OFDM symbols). This property is shown below.

[0304] For example, Table 1 shows an example for m=0:17

[0305] The 8 rows (rows 0-8) shown in Table 1 represent different cyclic shifts for indicating different SBTIs. Different columns are used to show the values ​​of the multipliers for DMRS REs. These cyclic shifts are orthogonal to each other.

[0306] It is also possible to use cyclically shifted DMRS in the time domain. The phase shift in the frequency domain is converted into a time index offset in the time domain. This can result in faster detection of SBTI (without multiple hypothesis testing).

[0307] Therefore (DMRS pbch2 / DMRS pbch1 ) is a difference estimate that is independent of the channel (if the channel does not change much from one symbol to another). The IFFT of these ratios for each STBI are time-shifted versions of each other. This allows coherent detection of the SBTI to be performed quickly and with lower complexity.

[0308] A scrambling sequence, which may be a function of the SBTI, may be applied to the reference DMRS to generate the indication DMRS. Using the scrambling pattern known at the receiver, a hypothesis for finding the SBTI may be generated and thus the SBTI may be detected.

[0309] The transmit power of REs used for PBCH DMRS may be higher than the transmit power of REs used for PBCH data. To achieve this, a power boost of a known factor may be applied to the PBCH DMRS transmission. It is important to know this factor at the receiver.

[0310] Although features and elements of the present invention are described in particular combinations in the preferred embodiments, each feature or element may be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. Although each of the beams shown in the figures are shown as a particular direction, it should be understood that this is for illustration purposes and is not intended to limit a particular beam format, width, or orientation.

[0311] Although the embodiments described in this application take into account LTE, LTE-A, New Radio (NR) or 5G specific protocols, it will be understood that the embodiments described in this application are not limited to this scenario and may also be applied to other wireless systems.

[0312] Although the features and elements are described above in specific combinations, it will be recognized by those skilled in the art that each feature or element can be used alone or in any combination with other features and elements. In addition, the methods described herein can be implemented in a computer program, software, or firmware that is introduced into a computer-readable medium for operation by a computer or processor. Examples of computer-readable media include electrical signals (transmitted via a wired or wireless connection) 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, buffer memory, semiconductor storage devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor associated with the software can be used to implement a radio frequency transceiver used in a WTRU, UE, terminal, base station, RNC, or any computer host.

Claims

1. A method performed by a wireless transmit / receive unit (WTRU), the method include: receiving at least one symbol of a synchronization signal block (SSB) comprising four symbols; wherein a first time symbol of the four symbols comprises a primary synchronization signal (PSS); The second time symbol of the four symbols includes a first physical broadcast channel (PBCH) signal and a first demodulation reference signal (DMRS); wherein a third time symbol of the four symbols comprises a secondary synchronization signal (SSS); and The fourth time symbol among the four symbols includes a second PBCH signal and a second DMRS. 2 . The method according to claim 1 , wherein the first DMRS and the second DMRS are located in the same subcarrier. 3 . The method according to claim 1 , wherein the first DMRS and the second DMRS are located at the same frequency position. 4 . The method of claim 1 , wherein the first DMRS is located in a subcarrier according to a cell identification (ID). The method of claim 1 , wherein the PSS and the SSS occupy the same frequency spectrum. The method of claim 1 , wherein the PBCH occupies a larger spectrum than the PSS and the SSS.

7. The method of claim 1, wherein the PBCH occupies a wider frequency spectrum than the PSS and the SSS.

8. The method according to claim 1, further comprising: include: An SSB time index is determined based on the first DMRS.

9. A wireless transmit / receive unit (WTRU), the WTRU include: a receiver configured to receive at least one symbol of a synchronization signal block (SSB) comprising four symbols; wherein a first time symbol of the four symbols comprises a primary synchronization signal (PSS); The second time symbol of the four symbols includes a first physical broadcast channel (PBCH) signal and a first demodulation reference signal (DMRS); wherein a third time symbol of the four symbols comprises a secondary synchronization signal (SSS); and The fourth time symbol among the four symbols includes a second PBCH signal and a second DMRS.

10. The WTRU of claim 9, wherein the first DMRS and the second DMRS are located in the same subcarrier.

11. The WTRU of claim 9, wherein the first DMRS and the second DMRS are located at the same frequency position.

12. The WTRU of claim 9, wherein the first DMRS is positioned in a subcarrier according to a cell identity (ID).

13. The WTRU of claim 9, wherein the PSS and the SSS occupy the same spectrum, and the PBCH occupies a larger spectrum than the PSS and the SSS.

14. The WTRU of claim 9, wherein the PBCH occupies a wider spectrum than the PSS and the SSS.

15. The WTRU of claim 9, further comprising: include: Circuitry configured to determine an SSB time index based on the first DMRS.

16. A network device, include: a transmitter configured to transmit at least one symbol of a synchronization signal block (SSB) comprising four symbols; wherein a first time symbol of the four symbols comprises a primary synchronization signal (PSS); The second time symbol of the four symbols includes a first physical broadcast channel (PBCH) signal and a first demodulation reference signal (DMRS); wherein a third time symbol of the four symbols comprises a secondary synchronization signal (SSS); and The fourth time symbol among the four symbols includes a second PBCH signal and a second DMRS. 17 . The network device of claim 16 , wherein the first DMRS and the second DMRS are located in the same subcarrier.

18. The network device of claim 16, wherein the first DMRS and the second DMRS are located at the same frequency position.

19. The network device according to claim 16, wherein the network device comprises a G Node B (gNB) and / or a transmission point (TRP).

20. The network device of claim 16, wherein the PSS and the SSS occupy the same frequency spectrum, and the PBCH occupies a larger frequency spectrum than the PSS and the SSS.

21. A method for demodulating a new radio physical broadcast channel NR-PBCH, the method include: Searching, by a wireless transmit / receive unit WTRU, for a new radio synchronization channel NR-SS signal; Check the quasi-collocated QCL indicator; If the value of the QCL indicator indicates a first configuration, performing channel estimation using both the NR-SS signal and the NR-PBCH demodulation reference signal NR-PBCH-DMRS; If the value of the QCL indicator indicates the second configuration, performing channel estimation using only the NR-PBCH-DMRS; and The NR-PBCH is demodulated using the estimated channel response.

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