Reference signal design for wireless communication systems

Abstract

To provide a system, a method, and means for transmitting a Phase Noise Reference Signal (PNRS).SOLUTION: A method includes, in a wireless transmission / reception unit (WTRU), steps of receiving scheduling information for physical uplink shared channel (PUSCH) transmission, the scheduling information including displaying a set of a physical resource block (PRB) and a modulation coding scheme (MCS) level, determining density for PNRS transmission on the basis of at least one of an MCS level, a frequency band for the PUSCH transmission, and subcarrier spacing for PUSCH transmission, and transmitting the PUSCH in a scheduled set of the PRBs using the determined PNRS density.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to reference signal design for a wireless communication system.

Background Art

[0002] Cross-reference to Related Applications This application claims priority and benefit of U.S. Patent Application No. 62 / 400,925, filed Sep. 28, 2016; U.S. Patent Application No. 62 / 454,617, filed Feb. 3, 2017; U.S. Patent Application No. 62 / 519,424, filed Jun. 14, 2017; and U.S. Patent Application No. 62 / 556,146, filed Sep. 8, 2017, which are hereby incorporated by reference in their entirety as if fully set forth herein.

[0003] 3GPP is working on an advanced wireless communication system sometimes called New Radio (NR). NR use cases can be summarized under one or more of several categories including enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), or / and ultra-reliable-and-low-latency communications (URLLC). Under the categories, there can be a wide set of use cases considered for various needs and deployment scenarios that may require specific performance requirements. For example, mMTC and URLLC use cases can span from the automotive industry to the health, agriculture, utility, and logistics industries.

[0004] In mMTC use cases, the system is Km with extended coverage, low power consumption, and / or low device complexity 2It is expected that it may be possible to support up to 1,000,000 mMTC devices per cell. To support high connection density, non-orthogonal multiple access techniques may be proposed for NR. In URLLC applications, the WTRU density per cell can be (e.g., significantly) lower. In URLLC, target delays shorter than 1 ms and / or 10 -5 High reliability in bit error rate could be a target. [Overview of the project]

[0005] A system, method, and means for transmitting a phase noise reference signal (PNRS) is disclosed, comprising: receiving scheduling information for a physical uplink shared channel (PUSCH) transmission in a wireless transceiver unit (WTRU), wherein the scheduling information includes an indication of a set of physical resource blocks (PRBs) and modulation coding scheme (MCS) levels; determining a density for a PNRS transmission based on at least one of the MCS levels, a frequency band for the PUSCH transmission, or a subcarrier spacing for the PUSCH transmission; and transmitting the PUSCH in a scheduled set of PRBs using the determined density of the PNRS. [Brief explanation of the drawing]

[0006] A more detailed understanding can be obtained from the following explanation, which is provided as an example along with the attached drawings.

[0007] [Figure 1A] This is a system diagram showing an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] Figure 1A is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used in the communication system shown. [Figure 1C] Figure 1A is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used within the communication system shown. [Figure 1D]Figure 1A is a system diagram showing further exemplary RAN and further exemplary CN that may be used within the communication system shown. [Figure 2] This shows an example of PNRS that uses the same subcarrier location across consecutive OFDM symbols. [Figure 3] An example of a PNRS with unused adjacent subcarriers is shown. [Figure 4] An example of a lower density PNRS pattern is shown. [Figure 5] This shows an example of pre-DFT PNRS insertion via puncturing. [Figure 6] An example of pre-DFT PNRS insertion via multiplexing is shown. [Figure 7] An example of pre-DFT PNRS insertion via multiplexing is shown. [Figure 8] An exemplary base PTRS pattern is shown along with the cyclic shift (CS) value. [Figure 9] Exemplary WTRU-specific zero-power and non-zero-power PTRS patterns with different CS values ​​are shown. [Figure 10] This shows an example of WTRU-specific OCC for PTRS tones within a PTRS chunk. [Figure 11] This shows an example of PNRS insertion after DFT via puncturing. [Figure 12] An example of PNRS insertion after DFT via multiplexing is shown. [Figure 13] An example of PNRS insertion after DFT via multiplexing is shown. [Figure 14] This shows an example of puncturing in OFDM for PNRS insertion. [Figure 15] An example of associating PNRS and EPDCCH resource sets is shown. [Figure 16] An example of the association between PNRS and PRB sets is shown. [Figure 17] An example of a distributed DM-RS mapped to the control / data portion of a subframe is shown. [Figure 18]An example of a WTRU transmitting the same SRS while the eNB sweeps its receive beam is shown. [Figure 19] An example of a WTRU sweeping its SRS is shown. [Figure 20] An example of SRS transmission for beam measurement is shown. [Figure 21] An example of SRS transmission using sub-band hopping is shown. [Figure 22] An example of SRS transmission and RE mute is shown. [Figure 23] An example of port multiplexing using IFDMA with orthogonal sequences and repetition is shown. [Figure 24] An example of FDM of DM-RS symbols without using time-domain cover codes is shown. [Figure 25] An example of FDM of DM-RS symbols using time-domain cover codes is shown. [Figure 26] An example of PNRS frequency density is shown. [Figure 26A] An example of PNRS frequency density is shown. [Figure 27] An example of determining the frequency density for PNRS transmission is shown.

Best Mode for Carrying Out the Invention

[0008] Figure 1A shows an exemplary 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, and broadcast to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), quadrature 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, and filter bank multicarrier (FBMC).

[0009] As shown in Figure 1A, 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, the internet 110, and other networks 112, but it should be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRU102a, 102b, 102c, and 102d, any of which may be called “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronics devices, and devices operating on commercial and / or industrial wireless networks. Any of WTRU102a, 102b, 102c, and 102d may interchangeably be called UE.

[0010] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be a transceiver base station (BTS), node B, enode B, home node B, home enode B, gNB, NR node B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are shown as single elements, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0011] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown) such as base station controllers (BSCs), radio network controllers (RNCs), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be called cells (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectrum. A cell may provide coverage for wireless service to a particular geographic area that may be relatively fixed or change over time. A cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers per sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0012] Base stations 114a, 114b may communicate with one or more WTRUs 102a, 102b, 102c, 102d via an air interface 116 which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0013] More specifically, as described above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 may implement radio technologies such as Universal Mobile (Telephone) Communication System (UMTS) Terrestrial Radio Access (UTRA) which can establish air interfaces 115 / 116 / 117 using broadband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Advanced HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0014] In one embodiment, base stations 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as Advanced UMTS Terrestrial Radio Access (E-UTRA) that can establish an air interface 116 using Long-Term Evolution (LTE) and / or LTE Advanced (LTE-A) and / or LTE Advanced Pro (LTE-A Pro).

[0015] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as NR radio access, which can establish an air interface 116 using New Radio (NR).

[0016] In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRU 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Thus, the air interface utilized by WTRU 102a, 102b, 102c may be characterized by transmissions made to and from multiple types of radio access technologies and / or multiple types of base stations (e.g., eNB and gNB).

[0017] In other embodiments, base stations 114a and WTRUs 102a, 102b, and 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi®)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Advanced High Speed ​​Data Rate (EDGE), and GSM EDGE (GERAN).

[0018] In Figure 1A, base station 114b could be, for example, a wireless router, home node B, home enode B, or access point, and could utilize any suitable RAT to facilitate wireless connectivity in localized areas such as workplaces, homes, vehicles, premises, industrial facilities, aerial corridors (for use by drones), roads, etc. In one embodiment, base station 114b and WTRU 102c, 102d could implement radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRU 102c, 102d could implement radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRU 102c, 102d could utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. As shown in Figure 1A, base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not need to access the internet 110 via CN 106 / 115.

[0019] RAN104 / 113 may communicate with CN106 / 115, which may be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU102a, 102b, 102c, and 102d. The data may have varying Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, internet connectivity, video distribution, and / or perform high-level security functions such as user authentication. Although not shown in Figure 1A, it should be understood that RAN104 / 113 and / or CN106 / 115 may communicate directly or indirectly with other RANs employing the same or different RATs as RAN104 / 113. For example, in addition to connecting to RAN104 / 113, which may utilize NR radio technology, CN106 / 115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0020] CN106 / 115 may also act as a gateway for WTRU102a, 102b, 102c, 102d to access PSTN108, the Internet 110, and / or other networks 112. PSTN108 may include a circuit-switched telephone network providing simple telephone services (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) within the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs that may employ the same RAT as RAN104 / 113 or a different RAT.

[0021] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multimode capability (for example, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a which may employ cellular-based radio technology and with base station 114b which may employ IEEE 802 radio technology.

[0022] Figure 1B is a system diagram showing an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 may include, in particular, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any partial combination of the above elements while remaining consistent with the embodiment.

[0023] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, another type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 that can be coupled to the transmit / receive element 122. Although the processor 118 and transceiver 120 are shown as separate components in Figure 1B, it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0024] The transmit / receive element 122 may be configured to transmit and / or receive signals from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It should be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0025] Although the transmit / receive element 122 is shown as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0026] The transceiver 120 may be configured to modulate the signal to be transmitted by the transmit / receive element 122 and to demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capability. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate over multiple RATs, such as NR and IEEE 802.11.

[0027] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (for example, a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input data from them. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132, and store data therein. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or other types of memory storage devices. The removable memory 132 may include a subscriber identification module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from memory not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data therein.

[0028] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0029] The processor 118 may also be coupled to a GPS chipset 136 which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (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 understood that the WTRU 102 may acquire location information by any preferred location determination method while remaining consistent with the embodiment.

[0030] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, e-compass, satellite transceiver, digital camera (for photos and / or video), Universal Serial Bus (USB) port, vibration device, television transceiver, hands-free headset, Bluetooth® module, frequency modulation (FM) radio unit, digital music player, media player, video game player module, internet browser, virtual reality and / or augmented reality (VR / AR) device, activity tracker, etc. Peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biosensor, and / or humidity sensor.

[0031] WTRU102 may include a full-duplex radio (for example, one relating to a particular subframe for both UL (for example, transmission) and downlink (for example, reception)) where the transmission and reception of some or all of the signal may be in parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference through signal processing either through hardware (e.g., chokes) or a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU102 may include a half-duplex radio (for example, one relating to a particular subframe for either UL (for example, transmission) or downlink (for example, reception)).

[0032] Figure 1C is a system diagram showing RAN104 and CN106 according to one embodiment. As described above, RAN104 may employ E-UTRA radio technology to communicate with WTRU102a, 102b, and 102c via the air interface 116. RAN104 may also communicate with CN106.

[0033] RAN104 may include enodes B160a, 160b, and 160c, but it should be understood that RAN104 may include any number of enodes B while remaining consistent with the embodiment. Each of enodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, enodes B160a, 160b, and 160c may implement MIMO technology. Thus, enode B160a may, for example, use multiple antennas to transmit and / or receive wireless signals from WTRU102a.

[0034] Each of the e-nodes B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. As shown in Figure 1C, the e-nodes B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0035] The CN106 shown in Figure 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the above elements is shown as part of CN106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0036] The MME162 can be connected to each of the e-nodes B162a, 162b, and 162c in RAN104 via the S1 interface and can function as a control node. For example, the MME162 may be responsible for authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting a specific serving gateway during the initial attach of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0037] The SGW164 can be connected to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions such as anchoring the user plane during handover between e-nodes B, triggering paging when DL data is available for WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0038] SGW164 may be connected to PGW166, which can provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0039] CN106 can facilitate communication with other networks. For example, CN106 can give WTRU102a, 102b, and 102c access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional fixed communication devices. For example, CN106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. Furthermore, CN106 can give WTRU102a, 102b, and 102c access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0040] Although the WTRU is shown as a wireless terminal in Figures 1A to 1D, in some typical embodiments where such a terminal may be used (for example, temporarily or permanently), wired communication is intended to interface with a communication network.

[0041] In a typical embodiment, the other network 112 may be a WLAN.

[0042] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interfaces with a distribution system (DS) or another type of wired / wireless network that carries traffic entering and leaving the BSS. Traffic originating from outside the BSS to an STA may arrive through the AP and be sent to the STA. Traffic originating from an STA to a destination outside the BSS may be sent to the AP for delivery to its respective destination. Traffic between STAs within the BSS may be sent through the AP, for example, here, a source STA may send traffic to the AP, and the AP may send traffic to the destination STA. Traffic between STAs within the BSS is considered and / or sometimes referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between a source STA and a destination STA (for example, directly between them) using a Direct Link Setup (DLS). In some typical embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with each other. The IBSS communication mode is sometimes referred to herein as the “ad hoc” communication mode.

[0043] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In some typical embodiments, Carrier Sensitivity Multiple Access / Collision Avoidance (CSMA / CA) may be implemented, for example, in the 802.11 system. In CSMA / CA, an STA, including the AP (e.g., any STA), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that particular STA may backoff. One STA (e.g., just one station) may transmit at a given time in a given BSS.

[0044] A high-throughput (HT) STA may use a 40MHz wide channel for communication via a combination of primary 20MHz channels, for example, with adjacent or non-adjacent 20MHz channels, in order to form a 40MHz wide channel.

[0045] Extremely high throughput (VHT) STAs may support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels may be formed by combining consecutive 20 MHz channels. 160 MHz channels may be formed by combining eight consecutive 20 MHz channels, or by combining two discontinuous 80 MHz channels, sometimes referred to as an 80+80 configuration. In an 80+80 configuration, data may be passed through a segment parser that can split the data into two streams after channel coding. Inverse fast Fourier transform (IFFT) processing and time-domain processing may be performed separately for each stream. Streams may be mapped onto two 80 MHz channels, and data may be transmitted by a transmitting STA. At the receiver of a receiving STA, the operation described above for the 80+80 configuration may be reversed, and the combined data may be sent to a media access control (MAC).

[0046] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications, such as MTC devices in a macro coverage area. The MTC device may have some capabilities, including limited capabilities, such as support for some and / or limited bandwidths (e.g., support for only that much). The MTC device may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0047] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the primary channel. 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 the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In the 802.11ah example, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes, the primary channel may be 1MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1MHz mode. Carrier detection and / or network allocation vector (NAV) settings may depend on the status of the primary channel. For example, if the primary channel is busy for an STA (which only supports 1MHz operating mode), a large portion of the frequency band remains idle, and transmitting the entire available frequency band to the AP may be considered busy, even if it could be available.

[0048] In the United States, the available frequency band that can be used by 802.11ah ranges from 902 MHz to 928 MHz. In South Korea, the available frequency band ranges from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band ranges from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah ranges from 6 MHz to 26 MHz, depending on the country code.

[0049] Figure 1D is a system diagram showing RAN113 and CN115 according to one embodiment. As described above, RAN113 may employ NR radio technology to communicate with WTRU102a, 102b, and 102c via air interface 116. RAN113 may also communicate with CN115.

[0050] RAN113 may include gNB180a, 180b, and 180c, but it should be understood that RAN113 may include any number of gNBs while remaining consistent with the embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 108b may utilize beamforming to transmit and / or receive signals from gNB180a, 180b, and 180c. Thus, gNB180a may use multiple antennas to transmit and / or receive wireless signals from, for example, WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple component carriers to WTRU102a (not shown). A subset of these component carriers may be on the unlicensed spectrum, while the remaining component carriers may be on the licensed spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multipoint (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0051] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions related to scalable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, cells, and / or parts of the wireless transmission spectrum. WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or lasting for varying lengths of absolute time).

[0052] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unlicensed bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with / connect to gNB180a, 180b, and 180c while also communicating with / connecting to other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNB180a, 180b, and 180c and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, enodes B160a, 160b, and 160c can act as mobility anchors for WTRU102a, 102b, and 102c, and gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0053] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interconnection between NR and E-UTRA, routing of user plane data to user plane functions (UPF) 184a and 184b, and routing of control plane information to access and mobility management functions (AMF) 182a and 182b. As shown in Figure 1D, the gNB180a, 180b, and 180c may communicate with each other via the Xn interface.

[0054] The CN115 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and optionally a Data Network (DN)185a, 185b. While each of the above elements is shown as part of CN115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0055] AMF182a and 182b may be connected to one or more of gNB180a, 180b, and 180c in RAN113 via the N2 interface and may function as control nodes. For example, AMF182a and 182b may be responsible for authenticating users of WTRU102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF183a and 183b, managing registration areas, terminating NAS signaling, and mobility management. Network slicing may be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of services utilized by WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services relying on high-reliability, low-latency (URLLC) access, services relying on extended large-scale mobile broadband (eMBB) access, and services using machine-type communications (MTC) access. The AMF162 may provide control plane functionality for switching between RAN113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0056] SMF183a and 183b can be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure traffic routing through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating IP addresses for WTRUs, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0057] UPF184a, 184b may be connected to one or more of the gNB180a, 180b, 180c in RAN113 via an N3 interface that can give WTRU102a, 102b, 102c access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, 102c and IP-enabled devices. UPF184, 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, and providing mobility anchoring.

[0058] CN115 can facilitate communication with other networks. For example, CN115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN115 and PSTN108. Furthermore, CN115 may grant WTRU102a,102b,102c 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, WTRU102a,102b,102c may be connected to the local data network (DN) 185a,185b through UPF184a,184b via an N3 interface to UPF184a,184b and an N6 interface between UPF184a,184b and DN185a,185b.

[0059] In view of Figures 1A-1D and the corresponding descriptions thereof, one or more or all of the functions described herein with respect to one or more of the WTRU102a-d, base stations 114a-b, enodes B160a-c, MME162, SGW164, PGW166, gNB180a-c, AMF182a-ab, UPF184a-b, SMF183a-b, DN185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). 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 to simulate network and / or WTRU functions.

[0060] Emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one, more or all of their functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communications network to test other devices in a communications network. One or more emulation devices may perform one, more or all of their functions while being temporarily implemented / deployed as part of a wired and / or wireless communications network. Emulation devices may be directly coupled to another device to be tested and / or to perform tests using over-the-air wireless communications.

[0061] One or more emulation devices may perform one or more functions, including all of the above, without being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test scenario in a test laboratory and / or an undeployed (e.g., for test) wired and / or wireless communication network to perform testing of one or more components. One or more emulation devices may be test equipment. To transmit and / or receive data, the emulation device may use direct RF coupling and / or wireless communication via RF circuitry (which may include, for example, one or more antennas).

[0062] In LTE, for example, orthogonal frequency division multiplexing (OFDM) may be used for downlink (DL) transmission, and / or discrete Fourier transform spread OFDM (DFT-s-OFDM) may be used for uplink (UL) transmission. In cyclic prefix (CP) DFT-s-OFDM (sometimes called single-carrier (SC) SC-FDMA with multiple access), data symbols may first be spread using DFT blocks and then mapped to the corresponding inputs of IDFT blocks. CP may be prepended at the beginning of symbols to avoid inter-symbol interference (ISI) and to enable one-tap frequency-domain equalization (FDE) at the receiver.

[0063] In downlink transmissions, reference symbols may be scattered across specific subcarriers; for example, one OFDM symbol may have a subcarrier loaded with data and the reference symbol. Common reference symbols may be transmitted over subcarriers distributed across the system bandwidth, and / or WTRU-specific reference signals may be distributed across subbands allocated to a particular WTRU.

[0064] Next-generation wireless communication systems may require reference signal designs to address phase noise issues that can arise when operating in high-frequency bands. In high-mobility scenarios, extensions to RS designs may be necessary, for example, to estimate and compensate for Doppler shifts. Having a common uplink / downlink / sidelink RS design with low overhead may be desirable.

[0065] For example, a system, method, and means for transmitting DL signals from multiple TRPs using a phase noise reference signal (PNRS) are disclosed. PNRS design / configuration, use of a PNRS with multiple TRPs, and a PNRS for UL transmission are disclosed.

[0066] If x is the OFDM symbol after IFFT (e.g., without CP), then θt is the transmitter's phase noise vector, and the received signal after CP rejection is:

[0067]

number

[0068] It may be described as follows.

[0069] After the DFT operation in the receiver,

[0070]

number

[0071] Thus, Θt=Fθt and H=Fh. This means that the data vector can be cyclically convolved with the phase noise spectrum, and the result can be scaled by the channel response. Depending on the phase noise spectrum, the data symbols for each subcarrier can be rotated with a common phase error and contaminated by intercarrier interference. The PSD of the phase noise can attenuate quickly, and the ICI contribution can be largely from adjacent subcarriers. If there is phase noise in the receiver,

[0072]

number

[0073] Here, Θr is the spectrum of the receiver's phase noise.

[0074] A reference signal may be used to compensate for phase noise, and the reference signal may be transmitted across consecutive OFDM symbols in a subframe (or TTI), which may allow for an accurate estimation of time-varying phase noise. The reference signal used to compensate for phase noise may be called a phase noise reference signal (PNRS) (PNRS may be used interchangeably with, for example, a phase tracking reference signal (PTRS), a phase noise compensation reference signal (PNCRS), and a phase error tracking reference signal (PETRS), the phase noise reference signal may be used to estimate phase noise, which may be used for other purposes including one or more of time and / or frequency offset tracking, synchronization, measurement (e.g., RSRP), CSI estimation (e.g., CQI, PMI), or demodulation of the downlink signal, or the PNRS may be transmitted across one or more subcarriers in an OFDM symbol, and the same subcarrier may be used across consecutive OFDM symbols in a time window (see, for example, Figures 2 and 3).

[0075] If PNRS is transmitted on one or more subcarriers in an OFDM symbol, and the same subcarrier may be used in consecutive OFDM symbols within a time window, then one or more of the following may apply: One or more subcarrier indices that may be used for PNRS transmission may be determined based on at least one system parameter (e.g., physical cell ID, virtual cell ID, TRP ID, subframe number, and / or radio frame number) to avoid PNRS collisions between adjacent cells. One or more time / frequency resources for PNRS that may be associated with another cell or TRP may be muted, reserved, or not used for downlink signal transmission. A subband (e.g., 12 subcarriers) may be reserved for PNRS transmission, and at least one subcarrier in the subband may be selected, determined, or used for PNRS transmission based on at least one system parameter. The subband may not be used for other downlink signal transmissions (e.g., control, data, and / or broadcast). One or more subcarrier indices that may be used for PNRS transmission may be predetermined. For example, a central subcarrier in the system bandwidth may be used for PNRS transmission. The number of subcarriers used for PNRS transmission may be indicated from the broadcast signal. One or more subcarrier indices may be one of the scheduled PRBs and subcarrier indices within a PRB that can carry PNRS.

[0076] Figure 2 shows an example of a PNRS that uses the same subcarrier location across consecutive OFDM symbols. Figure 3 shows an example of a PNRS with unused adjacent subcarriers.

[0077] Lower density PNRS patterns can be defined. For example, if the correlation time of phase noise is longer than the OFDM symbol length, these lower density PNRS patterns can be constructed by eNBs. An example of a lower density PNRS pattern is shown in Figure 4. The density of PNRS can be determined based on the density in the time domain (e.g., the number of OFDM symbols containing PNRS within a time window (e.g., slots, subframes, TTIs)) and / or the density in the frequency domain (e.g., the number of subcarriers used for PNRS within a system bandwidth, PRB, PRB pairs, or scheduled bandwidth)). Figure 3 shows an example of a high-density PNRS (e.g., in the time domain). Figure 4 shows an example of a low-density PNRS (e.g., in the time domain), where the lower density PNRS may use a subset of PNRS transmitted or used for higher density PNRS.

[0078] PNRS can be configured for lower or higher density patterns depending on the numerology (e.g., subcarrier spacing and OFDM symbol duration). For example, in a system operating with short OFDM symbol durations, a lower density PNRS pattern may be used, for example, when the correlation time of phase noise is longer than the OFDM symbol duration. The PNRS density (or density pattern) may be determined based on one or more of the subcarrier spacing, scheduled bandwidth, TTI length, presence of additional DM-RS, resource allocation type, or number of layers used or configured for unicast traffic (e.g., PDSCH, PUSCH).

[0079] Subcarrier spacing can be used or configured for unicast traffic (e.g., PDSCH, PUSCH). A set of subcarrier spacings can be used for unicast traffic, and one of the subcarrier spacings can be configured or used for PDSCH or PUSCH transmissions. For example, PNRS density can be determined based on the subcarrier spacing used or configured. For example, a set of subcarrier spacings {15, 30, 60, 120, 240} kHz can be used, and if the WTRU is configured with subcarrier spacing {15} kHz, no PNRS may be transmitted (e.g., zero PNRS density), and if the WTRU is configured with subcarrier spacing {240} kHz, a high-density PNRS may be used. A set of PNRS densities can be used, and a subset of PNRS densities can be determined based on the subcarrier spacing used. One PNRS density within a subset can be determined based on other scheduling parameters (e.g., modulation order, MCS level, scheduling bandwidth, number of layers, etc.). For example, Nd PNRS densities may be used as {PNRS-1, PNRS-2, ..., PNRS-Nd}, and each subcarrier interval may be associated with a subset of PNRS densities. For example, the first subcarrier interval (e.g., 15 kHz) may be associated with the subset of PNRS densities {PNRS-1}, the second subcarrier interval (e.g., 30 kHz) may be associated with the subset of PNRS densities {PNRS-1, PNRS-2}, the third subcarrier interval (e.g., 240 kHz) may be associated with the subset of PNRS densities {PNRS-Nd-1, PNRS-Nd}, and so on. PNRS density subsets may be determined based on the determined subcarrier intervals. Within a subset of PNRS densities, one PNRS density may be determined for PDSCH or PUSCH transmissions based, for example, on one or more scheduling parameters. PNRS-1 may be a zero PNRS density with no PNRS within the scheduled bandwidth.

[0080] PNRS density can be determined based on the bandwidth scheduled for a PDSCH or PUSCH. For example, the number of subcarriers used for PNRS within a scheduled bandwidth can be determined based on the number of PRBs or PRB pairs allocated within the scheduled bandwidth. One or more subcarriers per scheduled PRB can be used for PNRS transmission or reception, for example, when the number of scheduled PRBs is less than a first threshold. A subset of PRBs within a scheduled resource can be used for PNRS transmission or reception when the number of scheduled PRBs is greater than or equal to a first threshold. A subset of PNRS density can be determined based on subcarrier spacing, and the PNRS density within a subset of PNRS density can be determined based on the number of scheduled PRBs (e.g., scheduled bandwidth). Scheduled bandwidth can be used interchangeably with the number of scheduled PRBs.

[0081] The PNRS frequency density can be determined based on the TTI length. The TTI length can be the number of OFDM or DFT-s-OFDM symbols used for PDSCH or PUSCH transmission or reception, where the default TTI length can be defined as slots (e.g., 14 OFDM symbols for a slot), and shorter TTI lengths can be defined as minislots (e.g., the number of OFDM symbols for a minislot can be 1 to 7 OFDM symbols). For example, the PNRS time density can be determined based on the TTI length. A higher frequency density PNRS can be used for a shorter TTI length. A lower frequency density PNRS can be used for a longer TTI length.

[0082] The DM-RS density may be determined based on the presence of additional DM-RSs, which may be transmitted if configured and / or determined based on one or more scheduling parameters. If additional DM-RSs exist, a lower density of PNRSs may be used, where the lower density of PNRSs may not include any PNRSs (e.g., zero PNRS density). The default DM-RS may be located in the first part of the slot (e.g., the first one or two OFDM symbols in the slot) and may be called a front-loaded DM-RS, while additional DM-RS may be located in the later part of the slot (e.g., at the end of the OFDM symbols in the downlink portion of the slot).

[0083] A first PNRS density may be used for a first resource allocation type (e.g., continuous frequency resource allocation), and a second PNRS density may be used for a second resource allocation type (e.g., discontinuous frequency resource allocation).

[0084] The PNRS density may be determined based on the number of layers used, where a layer can be a data stream, and the number of layers may be used interchangeably with the transmission rank. A higher density may be used for a larger number of layers, and a lower density may be used for a smaller number of layers.

[0085] PNRS can be inserted as input to an IFFT block (for example, when OFDM is used for transmission), and it can be transmitted over reserved subcarriers, for example, as shown in Figures 2 and 3. In Figure 3, the subcarriers adjacent to the PNRS are left blank, which may minimize interference with the PNRS. PNRS can be inserted as input to a DFT block along with data symbols (for example, when DFT-s-OFDM is used for transmission). PNRS can be inserted in the time domain after an IFFT by, for example, puncturing some of the time domain samples and replacing them with pilot symbols. Adjacent subcarriers (for example, the subcarrier following the subcarrier containing the PNRS) may be blank, unused, and / or muted. WTRU can be scheduled in a subband that may contain the PNRS and its adjacent subcarriers. WTRU may assume that adjacent subcarriers are muted, and WTRU may rate match around adjacent subcarriers for its scheduled downlink transmission, or it may puncture them.

[0086] Puncturing and / or multiplexing of the PNRS may be provided. Below, the phase noise reference signal (PNRS) and the phase tracking reference signal (PTRS) may be used interchangeably.

[0087] A pre-DFT PTRS may be provided. A phase noise reference signal may be inserted into the DFT block in a system that transmits using a DFT-s-OFDM waveform. One or more of the following features (for example, those related to those shown in Figures 5 and 6) may be applied.

[0088] In the example, puncturing may be provided. Figure 5 shows an example of pre-DFT PNRS insertion via puncturing. The number of data symbols may correspond to the number of DFT inputs. Some of these data symbols may be punctured and / or replaced with reference symbols, for example, before they are mapped to the corresponding inputs of the DFT blocks. As an example, suppose one subframe has 14 OFDM symbols and 24 subcarriers are allocated for data transmission, and therefore the size of the DFT is set to 24. If QPSK is used, 24 × 14 = 336 QPSK symbols may be transmitted in the subframe. At a coding rate of 1 / 2, this may correspond to 336 information bits. If four reference symbols are transmitted for each OFDM symbol, 20 QPSK symbols (e.g., only 20 QPSK symbols) may be mapped to the DFT blocks. The remaining four QPSK symbols may be replaced with reference symbols.

[0089] In the example, multiplexing may be provided. Figure 6 shows an example of pre-DFT PNRS insertion via multiplexing. The number of data symbols to be transmitted in the OFDM symbols may be less than the DFT size. After the data symbols have been mapped to the corresponding inputs of the DFT, it may still be possible to insert additional symbols into the DFT block. These additional symbols may be selected to become reference symbols. Using the same example above, with multiplexing, the number of information bits transmitted in the subframe may be 280 bits. After 1 / 2 rate coding and QPSK modulation, each OFDM block may transmit 20 QPSK symbols. For example, since the DFT size is 24, the remaining 4 inputs of the DFT block may be used by PNRS.

[0090] The PNRS density in a DFT-s-OFDM using pre-DFT PNRS insertion may be determined based on the number of DFT-s-OFDM symbols containing PTRS, sometimes called the PNRS time density, and may be determined based on the number of symbols in the data symbols (or data symbol vector) for the DFT input, sometimes called the PNRS frequency density. The PNRS density may be determined based on one or more of the DFT size or the number of DFT blocks. For example, the DFT size of a DFT-s-OFDM for push transmission may be used to determine the PNRS frequency density (e.g., the number of symbols used for PNRS in the data symbol vector). One or more DFT blocks may be used for push transmission, and the PNRS density may be determined based on the number of DFT blocks. A higher PNRS density may be used when the number of DFT blocks is greater than 1, while a lower PNRS density may be used when the number of DFT blocks is 1. The number of DFT blocks may be greater than 1 if the scheduled uplink resources are not contiguous in the frequency domain.

[0091] Chunk-based pre-DFT PTRS insertion can be performed. The PTRS pattern for chunk-based pre-DFT PTRS insertion can be determined based on at least one of the following: the number of PTRS chunks (Nc), the chunk size (Ns), or the location of Nc chunks within the DFT input (or DFT input signal). Figure 7 shows an example of a PTRS pattern with Nc and Ns values, where Nc=N chunks with Ns=3 are used. The chunk size (Ns) can be the number of PTRS tones within a chunk. PTRS tones can be interchangeable with PTRS samples, PTRS REs, and / or PTRS subcarriers.

[0092] A group of PTRS patterns that may have the same density is sometimes called a PTRS type. PTRS patterns within the same PTRS type may have different Ns and / or Nc values, but the total number of PTRS tones (e.g., Ns × Nc) will be the same. The total number of PTRS tones can be used interchangeably with PTRS density.

[0093] In the example, the first PTRS type (e.g., PTRS type-1) may be based on a PTRS density of 4. The first PTRS pattern in PTRS type-1 may be Nc=2 and Ns=2, and the second PTRS pattern in PTRS type-1 may be Nc=4 and Ns=1.

[0094] In the example, the first PTRS type (e.g., PTRS type-1) may be based on a PTRS density of 4. PTRS patterns in PTRS type-1 may have the same Nc and Ns values, but the locations of the Nc chunks may differ. For example, if Nc=2, the first PTRS pattern may have PTRS chunks before and after the DFT input. The second PTRS pattern may have PTRS chunks in the middle and at the end of the DFT input. The third PTRS pattern may have PTRS chunks at the beginning and in the middle.

[0095] The locations of Nc chunks in the DFT input may be determined based on the cyclic shift values ​​of the DFT input signal and / or the IDFT output signal. A base PTRS pattern may be defined, determined, or constructed, and its cyclic shifted versions may be considered, or referred to as, different PTRS patterns within the same PTRS type. For example, a base PTRS pattern may be called a PTRS pattern with a cyclic shift value of 0 (e.g., CS=0), and a cyclic shifted version of the base PTRS pattern may be called a PTRS pattern with a cyclic shift value (e.g., CS=1). A cyclic shifted version of the base PTRS pattern may be called a PTRS pattern within the same PTRS type.

[0096] PTRS density can vary based on the PTRS pattern and / or PTRS type. For example, a first PTRS pattern (or PTRS type) may have a first PTRS density, and a second PTRS pattern (or PTRS type) may have a second PTRS density, where the first PTRS density may be higher than the second PTRS density. PTRS density is sometimes referred to as the number of PTRS tones for the DFT input and / or the number of DFT-s-OFDM symbols containing PTRS during PUSCH transmission. PTRS density is sometimes referred to as the number of PTRS subcarriers within a scheduled bandwidth and / or the number of OFDM symbols containing PTRS in PUSCH or PDSCH. The PTRS density (in the frequency domain, sometimes referred to as PTRS subcarriers) is used for every Np scheduled PRBs, where the starting PRB can be determined based on at least one of a fixed number (e.g., the first PRB of the scheduled PRBs), a configured number (e.g., parameters configured in the upper layers), a number determined based on WTRU-specific parameters (e.g., WTRU-ID, scrambling ID), and a cell-specific parameter (e.g., cell ID). The allocated PRBs can be ordered from 0 to Nprb-1 regardless of PRB location, where Nprb is sometimes referred to as the number of PRBs allocated for the WTRU.

[0097] The PTRS density, PTRS pattern, chunk size of the PTRS pattern, number of chunks in the PTRS pattern, and / or PTRS type for push transmission may be determined based on at least one of the scheduled bandwidth, modulation order or modulation and coding scheme (MCS) level, numerology, transport block size (TBS), and / or DM-RS configuration for scheduled push transmission. The numerology may include at least one of the subcarrier spacing, slot length, TTI length, and CP length.

[0098] In the example, a first PTRS pattern may be used if the scheduled bandwidth for push transmission is less than or equal to a first threshold, and a second PTRS pattern may be used if the scheduled bandwidth for push transmission is greater than the first threshold but less than or equal to a second threshold. The scheduled bandwidth may be used in compatibility with the DFT input size.

[0099] In the example, a first PTRS pattern may be used if the scheduled modulation order or MCS level is less than or equal to a first threshold, and a second PTRS pattern may be used if the scheduled modulation order or MCS level is greater than the first threshold but less than or equal to a second threshold.

[0100] A DM-RS configuration may be based on the number of DM-RS symbols (for example, DFT-s-OFDM symbols or CP-OFDM symbols used for DM-RS transmission) and / or the location of the DM-RS symbols. For example, a first DM-RS configuration may have two DM-RS symbols that may be located between the first two DFT-s-OFDM symbols or CP-OFDM symbols, and a second DM-RS configuration may have two DM-RS symbols that may be located between the first DFT-s-OFDM symbols or CP-OFDM symbols and the last DFT-s-OFDM symbol or CP-OFDM symbol.

[0101] Pre-DFT PTRS insertion may be performed for multi-user transmission. A base PTRS pattern with cyclically shifted values ​​may be used, where the base PTRS pattern may be determined based on the locations of Ns, Nc, or Nc chunks, and its cyclically shifted version may have the same Ns and Nc, but the locations of Nc chunks may have an offset (e.g., a time offset) from the base PTRS pattern. Figure 8 shows an example of a base PTRS pattern (e.g., CS=0) and a cyclically shifted version of that base PTRS pattern.

[0102] A base PTRS pattern and a cyclically shifted version of that base PTRS pattern may be used. The base PTRS pattern may be used, configured, or determined based on one or more scheduling parameters, including at least one of the scheduled bandwidth, number of PRBs, TTI length, DM-RS configuration, MCS level, and transport block size. The cyclic shift value may be determined based on WTRU-specific parameters or indicators in the associated DCI.

[0103] The set of cyclic shift values ​​may be constructed via upper-layer signaling. Alternatively, the set of cyclic shift values ​​may be determined based on one or more of the following: the base PTRS pattern, the scheduled bandwidth, and / or the frequency locations of the scheduled bandwidth.

[0104] WTRU-specific parameters may include at least one of the following: WTRU capability, WTRU category, and WTRU-ID (e.g., C-RNTI, IMSI modulo X). The WTRU-ID modulo Ncs may be used to determine the cyclic shift value. Ncs may be the maximum number of cyclic shift values ​​or the total number of cyclic shift values. The DM-RS configuration may include at least one of the following: the number of symbols used for DM-RS transmission, the time / frequency location of the DM-RS symbols, and / or the number of DM-RS antenna ports indicated for PUSCH transmission.

[0105] Zero-power PTRS may be used. For example, if a WTRU is scheduled for a push transmission, the WTRU may be instructed to transmit one or more zero-power PTRS. The zero-power PTRS pattern may be determined based on the base PTRS pattern and its cyclically shifted version. The WTRU may avoid signaling over the RE for the zero-power PTRS.

[0106] Figure 9 shows exemplary WTRU-specific zero-power and non-zero-power PTRS patterns with different CS values. The PUSCH RE for zero-power PTRS may be punctured or rate-matched around it. The reference signal sequence for zero-power PTRS may all be zero values. The base PTRS pattern for zero-power PTRS may be the same as the non-zero-power PTRS pattern, and the cyclic shift values ​​may differ between the zero-power and non-zero-power PTRS patterns. The cyclic shift values ​​for zero-power PTRS patterns may be shown as part of the scheduling parameters. The cyclic shift values ​​for zero-power PTRS patterns may be determined based on the cyclic shift values ​​of non-zero-power PTRS patterns. The cyclic shift values ​​for zero-power PTRS patterns may be determined based on the DM-RS port number allocated for PUSCH transmission. The base PTRS pattern for zero-power PTRS and its cyclically shifted version may be configured separately, for example, via upper-layer signaling.

[0107] Figure 10 shows an exemplary WTRU-specific OCC for PTRS tones within a PTRS chunk. An orthogonal cover code (OCC) can be used for PTRS. For example, an OCC can be used for PTRS tones within a chunk. The OCC can be used interchangeably with orthogonal sequences, random sequences, PN sequences, Zadoff-Chu sequences, scramble sequences, and / or Gorey sequences. The OCC can be determined based on the chunk size and one or more WTRU-specific parameters. For example, if WTRU-ID modulo 2 is "0", a first OCC (e.g.,

[0011] ) may be used for PTRS tones in each chunk, and if WTRU-ID modulo 2 is "1", a second OCC (e.g., [1-1]) may be used for PTRS tones in each chunk. OCC parameters may be shown in the associated DCI. OCC parameters can be determined based on one or more scheduling parameters. For example, the OCC parameter for PTRS can be determined based on the DM-RS configuration (e.g., DM-RS ports). If the WTRU is configured on DM-RS port 0, the WTRU may use a first OCC (e.g.,

[0011] ), and if the WTRU is configured on DM-RS port 1, the WTRU may use a second OCC (e.g., [1-1]). If the OCC is based on a scramble sequence, the initialization of the scramble sequence may be based on the WTRU-ID.

[0108] A pre-DFT PTRS may be provided. A phase noise reference signal may be inserted into the IDFT block in a system that transmits using a DFT-s-OFDM waveform. One or more of the following features (for example, those related to those shown in Figures 11 and 12) may be applied.

[0109] In the example, puncturing may be provided. Figure 11 shows an example of post-DFT PNRS insertion via puncturing. Some outputs of the DFT block are punctured and replaced with reference symbols.

[0110] In the example, multiplexing may be provided. Figure 12 shows an example of post-DFT PNRS insertion via multiplexing. The outputs of the DFT block and reference symbol can be multiplexed and mapped to the corresponding subcarriers.

[0111] The locations of the phase noise reference symbols shown in the figure are illustrative locations, and they may be mapped to inputs different from those shown. For example, PNRS may be mapped to IDFT as shown in Figure 13, which illustrates an example of DFT-post PNRS insertion via multiplexing. Subcarriers used for PNRS transmission by one WTRU may similarly be used by other WTRUs to transmit PNRS. In such cases, PNRS from different WTRUs may need to be orthogonalized in the time domain by using spread and / or orthogonal cover codes (e.g., via consecutive OFDM symbols).

[0112] In the example, one or more PNRS types may be used for DFT-s-OFDM. For example, a first PNRS type may be used when single-user MIMO transmission is used, and a second PNRS type may be used when multi-user MIMO transmission is used, where the first PNRS type may be a post-DFT PNRS and the second PNRS type may be a pre-DFT PNRS.

[0113] The PNRS type (e.g., pre-DFT PNRS or post-DFT PNRS) or PNRS scheme (e.g., multiplexing or puncturing) for DFT-s-OFDM transmission may be determined based on one or more of the following: the uplink MIMO transmission mode or scheme used, the modulation order used, the channel coding scheme used, the scheduled transport block size, the number of scheduled resource blocks, or the number of DFT-s-OFDM symbols used in a slot or minislot.

[0114] Uplink MIMO transmission modes or schemes may be used. For example, a closed-loop transmission scheme may use a first PNRS type / scheme, and an open-loop transmission scheme may use a second PNRS type / scheme.

[0115] Modulation order may be used. For example, lower modulation orders (e.g., QPSK and 16QAM) may use a first PNRS type / scheme, while higher modulation orders (e.g., 64QAM) may use a second PNRS type / scheme.

[0116] A channel coding scheme may be used. For example, a first channel coding scheme (e.g., LDPC) may use a first PNRS type / scheme, and a second channel coding scheme (e.g., pole) may use a second PNRS type / scheme.

[0117] The transport block size can be scheduled. For example, if the transport block size is greater than a predetermined threshold, the first PNRS type / method may be used; otherwise, the second PNRS type / method may be used.

[0118] PNRS can be provided using OFDM. PNRS transmission can be turned on and off on a user basis. The number of PNRS can vary adaptively depending on the modulation order and / or other parameters. The number of subcarriers allocated to PNRS can vary, which may necessitate an adaptive change in the transport block size. For example, the transport block size can remain constant even when PNRS is turned on or when the number of PNRS is changed. Puncturing can be introduced to map data symbols to available data subcarriers. An example is shown in Figure 14, which illustrates exemplary puncturing in OFDM for PNRS insertion. Data symbols planned to be transmitted on a subcarrier carrying a PNRS can be punctured and replaced with the PNRS, for example, when a PNRS must be transmitted.

[0119] Configuration of puncturing and / or multiplexing patterns may be provided. PNRS multiplexing and / or puncturing patterns (e.g., the number of PNRS symbols in OFDM symbols, which inputs of DFT and / or IDFT are used to feed into the PNRS, and which OFDM symbols have PNRS) may be configured by a central controller. The number of PNRS symbols in OFDM symbols may be referred to as the frequency density (or frequency pattern) of PNRS, and the number of OFDM symbols having PNRS may be referred to as the time density (or time pattern) of PNRS. For example, one or more of the following may be applied for configuring puncturing and / or multiplexing patterns:

[0120] The PNRS pattern or pattern subset may be determined based on one or more of the following: operating frequency bandwidth, MCS level (e.g., modulation order and / or coding rate), numerology (e.g., subcarrier spacing and / or system bandwidth), upper layer signaling, scheduled bandwidth (or number of scheduled PRBs), number of layers for SU-MIMO transmission (e.g., transmit rank), MIMO operating mode (e.g., SU-MIMO or MU-MIMO), waveform used (e.g., CP-OFDM or DFT-s-OFDM), and / or DM-RS density (e.g., front-loaded DM-RS only or front-loaded DM-RS with additional DM-RS, number of OFDM or DFT-s-OFDM symbols used for DM-RS).

[0121] All or a subset of PRBs may be used for PNRS transmission. If a subset of PRBs carries PNRS, the subset of PRBs that carry PNRS may be determined based on one or more of the DM-RS ports or sets of DM-RS ports indicated in the allocated or associated DCI or WTRU-specific parameters. For example, the DM-RS ports or sets of DM-RS ports may be allocated or indicated in the associated DCI for MU-MIMO operation, and the set of PRBs that can carry PNRS may be determined based on the allocated DM-RS ports or sets of DM-RS ports. If a first DM-RS port (or a first set of DM-RS ports) is indicated, every other PRB with PRB offset = 0 may contain PNRS, and if a second DM-RS port (or a second set of DM-RS ports) is indicated, every other PRB with PRB offset = 1 may contain PNRS. WTRU-specific parameters (e.g., WTRU ID, C-RNTI, scrambling identifier, PNRS scrambling identifier, etc.) may be provided. For example, a first WTRU may transmit (or receive) every other scheduled PRB with PRB offset = 0, while a second WTRU may transmit (or receive) every other scheduled PRB with PRB offset = 1, where the PRB offset may be determined based on WTRU-specific parameters.

[0122] For scheduled UL transmissions, the eNB may signal to the WTRU which PNRS pattern to use. The eNB may signal this information to the WTRU, for example, along with the UL authorization. One or more of the following may apply: all RBs allocated for a UL transmission (e.g., all RBs allocated for a UL transmission) may be configured to carry at least one PNRS (e.g., when PNRS are supplied to the IDFT); possible patterns may be predetermined, for example, the eNB may signal to the WTRU the index of the desired pattern; the PNRS pattern to use may be determined (e.g. implicitly) based on the number of allocated PRBs; and / or the PNRS pattern to use may be determined (e.g. implicitly) based on the MCS level indicated in the UL authorization.

[0123] In a scheduled DL transmission, the eNB may signal to the WTRU that a PNRS pattern will be used during the transmission. The eNB may signal this information to the WTRU, for example, along with the DL authorization. One or more of the following may apply: the RB allocated for the DL transmission (e.g., all RBs allocated for the DL transmission) may be configured to carry at least one PNRS (e.g., when PNRS are supplied to the IDFT); possible patterns may be predetermined, for example, the eNB may signal to the WTRU an index of a desired pattern; the PNRS pattern to be used may be determined (e.g. implicitly) based on the number of allocated PRBs; and / or the PNRS pattern to be used may be determined (e.g. implicitly) based on the MCS level indicated in the UL authorization.

[0124] In UL transmission using DFT-s-OFDM, when the PNRS is supplied to the DFT block, one or more of the following may apply: A contiguous set of DFT inputs may be used to transmit the PNRS, for example, starting from the smallest index. A contiguous set of DFT inputs may be used to transmit the PNRS, starting from the largest index. A set of DFT inputs may be used to transmit the PNRS, for example, here the set of inputs may be determined based on one or more of a given location, WTRU parameters (e.g., WTRU-ID), service type (e.g., URLLC, eMBB, and mMTC), or system parameters (e.g., subframe number, radio frame number, cell ID).

[0125] In UL transmission using OFDM, when the PNRS is supplied to the IDFT block by puncturing or multiplexing, one or more of the following may apply: The first PRB of a scheduled PRB for uplink transmission may be used to transmit the UL PNRS, for example, here the first PRB may be the PRB with the smallest index among the PRBs scheduled for the WTRU. In the example, the first PRB may be the PRB with the highest index among the PRBs scheduled for the WTRU. A PRB of a scheduled PRB for uplink transmission may be used to transmit the UL PNRS, for example, here a PRB may be determined based on one or more of the following: a given location (e.g., the first or last PRB in a scheduled PRB), WTRU-specific parameters (e.g., WTRU-ID), service type (e.g., URLLC, eMBB, and mMTC), or system parameters (e.g., subframe number, radio frame number, cell ID). The first N subcarriers of the first PRB in a scheduled PRB may be used to transmit the UL PNRS. The first N subcarriers of the last PRB in a scheduled PRB may be used to transmit UL PNRS.

[0126] The multiplexing and / or puncturing pattern for PNRS may be implicitly determined, for example, from resource allocation. For example, the number of allocated subcarriers, modulation order, and / or transport block size may be determined based on how many inputs of the DFT and / or IDFT do not need to be used for data transmission. These inputs may then be used for PNRS transmission. The location of the PNRS (e.g., which inputs of the DFT and / or IDFT should be supplied during the PNRS) may not be implicitly known and may be pre-configured. For example, the first / last N inputs may be used to transmit the PNRS. The PNRS may be distributed to allocated resources using a predetermined rule (e.g., uniformly starting from resource index = 0).

[0127] For example, when data and PNRS multiplexing is used, the transport block size (e.g., of the data blocks to be transmitted) may vary based on the number of resources allocated for PNRS. The WTRU may determine the actual transport block size used for transmission from the nominal transport block size signaled by the eNB and / or the PNRS configuration. As an example, assuming the eNB signals the WTRU to transmit a block size of N information bits using 16QAM modulation and a coding rate of 1 / 2, this results in {(N×2) / log2(16)} = N / 2 subcarriers being used for transmission (e.g., N / 2 DFT size if DFT-s-OFDM is used). If K resources (e.g., subcarriers) are reserved for PNRS over the duration of the subframe, the actual transport block size could be N-2K information bits. The same can be applied to determining the transport block size in DL transmissions.

[0128] PNRS can be used with multiple TRPs. One or more types of PNRS can be used. For example, a first type of PNRS may be common to (or shared by (e.g., all) WTRUs in a cell), while a second type of PNRS may be specific to a WTRU or a group of WTRUs. A first type of PNRS may be transmitted in a predetermined or given location, while a second type of PNRS may be transmitted through a scheduled resource. A first type of PNRS may be used as a default PNRS. A second type of PNRS may be used as a supplementary PNRS. A second type of PNRS may be transmitted or presented based on one or more conditions. For example, a second type of PNRS may exist in (or be transmitted within) a scheduled resource based on one or more scheduling parameters. One or more of the following may apply: if the modulation order is higher than a predetermined threshold, a second type of PNRS may exist; for example, if the modulation order is higher than QPSK (e.g., 16QAM or 64QAM), a second type of PNRS may exist; or if the transmission rank is higher than a predetermined threshold, a second type of PNRS may exist.

[0129] One or more PNRS configurations may be transmitted or used. The associated PNRS for demodulation may be determined based on the downlink channel type. For example, two PNRS configurations may be used, with the first PNRS configuration associated with the downlink control channel and the second PNRS configuration associated with the downlink data channel. A PNRS configuration may include one or more of the following: time / frequency location, associated transmit / receive point (TRP), reference signal power, scrambling code, scrambling ID, or periodicity. The first PNRS configuration may be associated with the downlink control channel (e.g., PDCCH), and the second PNRS configuration may be associated with the downlink data channel (e.g., PDSCH). The association between PNRS configurations and downlink channels may be predetermined, configured via higher layers, or dynamically indicated. The first PNRS configuration may be associated with the downlink control channel, and one or more PNRS configurations may be associated with the downlink data channels.

[0130] The downlink control channel, PDCCH, and extended PDCCH (EPDCCH) can be used interchangeably.

[0131] One or more PNRS configurations may be transmitted or used for downlink signal transmission, and herein, one or more PNRS may be used for downlink signal demodulation. The associated PNRS may be indicated to the WTRU for downlink signal demodulation. For example, multiple PNRS configurations may be transmitted or used, and one of the PNRS configurations may be associated for a physical downlink shared data channel (PDSCH) that can be scheduled for the WTRU. For PDSCH demodulation, the WTRU may be indicated which of the multiple PNRS configurations should be used. One or more of the following may apply: the associated PNRS configuration for the downlink data channel may be indicated, or the associated PNRS configuration for the control channel may be determined.

[0132] An associated PNRS configuration for a downlink data channel may indicate one or more of the following: an associated DCI that can be used to schedule a PDSCH; the location of the scheduled PDSCH, e.g., the time and / or frequency location of the scheduled PDSCH, which can determine the associated PNRS configuration; the location of the DL control channel search space where the associated DCI is received (e.g., the DL control channel search space (SS) may be segmented, and each segmented DL control channel search space may be associated with a PNRS configuration; and / or, if a WTRU receives a DCI in a segmented DL control channel search space, the WTRU may know which PNRS configuration to use; or an RNTI used for the associated DCI may determine the associated PNRS configuration, e.g., one or more RNTIs may be used for the DCI, and each RNTI may be associated with a specific PNRS configuration.

[0133] The associated PNRS configuration for a control channel may be determined based on one or more of the following: The DL control search space (SS) may be partitioned, and each partition of the DL control SS may be associated with a specific PNRS configuration. For example, if a WTRU monitors a partitioned DL control SS, the WTRU may use the associated PNRS configuration for the partitioned DL control SS. The associated PNRS for each partition of the DL control SS may be predetermined, configured, or signaled. One or more DL control decoding candidates may be monitored in the DL control SS, and (for example, each) DL control decoding candidate may be associated with a specific PNRS configuration. (For example, the associated PNRS for each) DL control decoding candidate may be predetermined, configured, or signaled. Time and / or frequency resources were used for the DL control channel. For example, a first time / frequency resource for the DL control channel may be associated with a first PNRS configuration, and a second time / frequency resource for the DL control channel may be associated with a second PNRS configuration. Time / frequency resources for DL ​​control channels are sometimes referred to as (E)PDCCH resource sets. (For example, each)(E)PDCCH resource set may be associated with a specific PNRS configuration. The association between an (E)PDCCH resource set and a PNRS configuration may be signaled, configured, or indicated in the configuration of the (E)PDCCH resource. PNRS configurations may be pre-configured via upper-layer signaling. (For example, each)PNRS configuration may be associated with an index.

[0134] Figure 15 shows an example of the association between PNRS and EPDCCH resource sets.

[0135] One or more operating modes may be used for demodulating downlink signals using PNRS. For example, a WTRU may demodulate a downlink signal with phase noise compensation based on a cell-specific PNRS in a first operating mode, or a WTRU may demodulate a downlink with phase noise compensation based on a WTRU-specific PNRS. When a WTRU is configured in the first operating mode, it may use a cell-specific PNRS for downlink signal demodulation, where the cell-specific PNRS may be located in a given location. When a WTRU is configured in the second operating mode, it may use a WTRU-specific PNRS for downlink signal demodulation, where the WTRU-specific PNRS may be located in a scheduled downlink resource.

[0136] One or more PRBs may be used to schedule PDSCHs, and one or more PRBs may be associated with one or more PNRS configurations. For example, each PRB may include its associated PNRS, and the WTRU may use the PNRS. The PNRS may be used for phase noise compensation. A separate reference signal for demodulation may be transmitted. For example, a first reference signal (e.g., PNRS) may be used to estimate phase noise, a second reference signal (e.g., DM-RS) may be used to estimate the channel, and the estimated phase noise and / or estimated channel may be used to demodulate the downlink signal. The number of antenna ports for the PNRS and the number of antenna ports for the DM-RS may differ. For example, a single antenna port may be used for the PNRS regardless of the transmit rank (e.g., the number of layers for downlink signal transmission), and the number of antenna ports for the DM-RS may be determined based on the transmit rank (e.g., the number of layers for associated downlink transmission). The number of PRBs associated with a PNRS configuration can be indicated, determined, or configured, for example, via upper-layer signaling. For example, a WTRU may be configured such that three PRBs can be associated with a PNRS, a WTRU may assume that a PNRS can be transmitted in at least one of the three PRBs associated with the same PNRS, or a WTRU may assume that a PNRS can be transmitted in a subset of the PRBs associated with the same PNRS.

[0137] Figure 16 shows an example of the association between PNRS and PRB sets.

[0138] One or more PRB groups (PRGs) may be used to determine the association between PRBs and PNRSs. A PRG may be defined as a set of consecutive PRBs in a subframe, and the number of PRGs in a subframe may be determined based on the total number of PRBs in the system bandwidth and the number of consecutive PRBs in the PRG. For example, if the total number of PRBs in the system bandwidth is 50 and the number of PRBs in a PRG is 5, then 10 PRGs may be used in a subframe. Each PRG may contain a PNRS. For example, the first PRB in a PRG may contain a PNRS. A WTRU may be scheduled in one or more PRBs in a subframe. A WTRU may use a PNRS located in the first PRB of the PRG for demodulation of the PRBs located in the PRG. A PRG may be associated with a TRP (or cell), and (for example, each) PRG may be associated with a specific TRP (or cell). The number of PRBs for a PRG may be configurable. The PRG size may be the same as the total number of PRBs (for example, a single TRP is used).

[0139] PNRS transmission can be dynamically turned on and off by the eNB. A WTRU may request PNRS transmission. PNRS transmission can be WTRU-specific or common. If it is common, the time / frequency resources reserved for its transmission may be configured by the eNB. If it is WTRU-specific, the eNB may signal PNRS transmission to the WTRU.

[0140] A PNRS for UL transmission may be disclosed. A WTRU may be configured for PNRS transmission in UL to allow, for example, an eNB to perform phase tracking to compensate for the phase noise of the WTRU transmitter.

[0141] In a PNRS configuration for a UL transmission, one or more of the following may apply: the presence or use of PNRS may be determined; the density of PNRS (e.g., one subcarrier, two subcarriers, etc.) may be determined; UL PNRS may be transmitted in one or more subcarriers within a scheduled uplink resource (e.g., a PRB); UL PNRS may be transmitted in one or more subcarriers within an OFDM symbol (and within consecutive OFDM symbols in an RB); the index of subcarriers within an RB used for UL PNRS transmission may be predetermined; or, in a scheduled UL transmission using multiple RBs, the eNB may signal to the WTRU which RB can carry the PNRS.

[0142] The presence or use of a PNRS may be determined based on the operating frequency band. For example, UL PNRS may not be used in lower operating frequency bands (e.g., below 6 GHz), while UL PNRS may be used in higher operating frequency bands (e.g., above 6 GHz). A WTRU may decide to use or transmit a PNRS based on the operating frequency band. The use or transmission of a PNRS may be indicated by the eNB.

[0143] The density of the PNRS (e.g., one subcarrier, two subcarriers, etc.) may be determined based on one or more of the following: the operating frequency bandwidth, the MCS level (e.g., modulation order and / or coding rate), the numerology (e.g., subcarrier spacing and / or system bandwidth), upper layer signaling (e.g., the association between PNRS density and MCS level may be determined based on upper layer signaling, the PNRS density for PDSCH or PUSCH transmission may be determined based on the MCS level indicated in the associated DCI), the scheduled bandwidth (e.g., the number of scheduled PRBs), the MIMO operating mode (e.g., SU-MIMO or MU-MIMO), and / or the number of layers (e.g., transmit rank).

[0144] UL PNRS may be transmitted in one or more subcarriers within a scheduled uplink resource (e.g., PRB). The first PRB of a scheduled PRB for uplink transmission may be used to transmit UL PNRS, wherein the first PRB may be the PRB with the smallest index among the PRBs scheduled for WTRU. The first PRB may be the PRB with the highest index among the PRBs scheduled for WTRU. A PRB of a scheduled PRB for uplink transmission may be used to transmit UL PNRS, wherein a PRB may be determined based on one or more of the following: a given location (e.g., the first or last PRB in a scheduled PRB), WTRU parameters (e.g., WTRU-ID, scramble ID, virtual ID), service type (e.g., URLLC, eMBB, and mMTC), or system parameters (e.g., subframe number, radio frame number, cell ID). The first subcarrier of the first PRB in a scheduled PRB may be used to transmit UL PNRS. The first N subcarriers of the first PRB in a scheduled PRB may be used to transmit UL PNRS.

[0145] UL PNRS may be transmitted in one or more subcarriers of an OFDM symbol and in consecutive OFDM symbols of an RB. OFDM symbols may be used interchangeably with SC-FDMA symbols, DFT-s-OFDM symbols, UW DFT-s-OFDM symbols, and ZT DFT-s-OFDM symbols.

[0146] The subcarrier index within the RB used for UL PNRS transmission can be predetermined; for example, it could be the central subcarrier of the RB. One or more of the following may be applied for UL PNRS subcarrier locations (and / or PRB locations):

[0147] In a scheduled UL transmission using multiple RBs, the eNB may signal to the WTRU which RBs can carry PNRS. Some RBs may not carry PNRS, for example, to reduce RS overhead. The eNB may signal this information to the WTRU, for example, along with UL authorization. One possibility is that RBs allocated for a UL transmission (e.g., all RBs) are configured for PNRS, or that a pattern of RBs that can be configured for PNRS is predetermined, and the eNB may need to signal an index of the desired pattern to the WTRU (e.g., only).

[0148] PNRS can be used to demodulate associated data. For example, a PNRS transmitted in one PRB can be used to demodulate data in the same PRB. One or more of the following may apply: A PNRS may be transmitted in one or more PRBs scheduled for a WTRU, and a WTRU (or eNB) may transmit a DM-RS in any PRB other than the one or more PRBs containing the PNRS (e.g., each PRB). A DM-RS may be signaled based on a first reference signal pattern (e.g., distributed within the PRB). A PNRS may be signaled based on a second reference signal pattern (e.g., localized within the PRB). A DM-RS location in one or more PRBs containing a PNRS can be used for data transmission. For example, if the transmission rank (e.g., number layer) for the data is higher than 1, a DM-RS may be transmitted in one or more PRBs containing a PNRS. PNRS may be transmitted in one or more PRBs scheduled for a WTRU, and the WTRU (or eNB) may transmit different types of DM-RS based on the presence of PNRS in the PRB. For example, if the scheduled PRB contains PNRS, a first type of DM-RS may be used; otherwise, a second type of DM-RS may be used. The reference signal pattern of the first type of DM-RS may differ from that of the second type of DM-RS. The first type of DM-RS may have a lower density (e.g., fewer REs) than the second type of DM-RS.

[0149] The eNB can estimate the rate of change of the transmitter's phase noise (for example, based on the eNB's phase offset measurement using the default PNRS settings) and configure the WTRU for alternative PNRS patterns, such as a lower density pattern (for example, shown in Figure 4).

[0150] Data demodulation reference signal (DM-RS) transmission is disclosed. In some frame structures, the DM-RS may be transmitted, for example, at the beginning of a frame / subframe / packet before data transmission begins. If the DM-RS is not transmitted in the OFDM symbol carrying the data, channel estimation accuracy may be impaired, for example, particularly in high-mobility scenarios.

[0151] Distributed DM-RS symbols may be mapped to the data portion of a frame / subframe / packet in addition to the initial DM-RS symbol of a subframe, for example, for both DL and UL transmissions to mitigate the degradation of channel estimation due to high mobility. Figure 17 shows an example of distributed DM-RS mapped to the control / data portion of a subframe. Distributed DM-RS may be dynamically signaled by the eNB or semi-statically configured.

[0152] The distributed DM-RS can be mapped, for example, to the data portion of a subframe with a reference signal of higher or lower density depending on mobility, with a higher density pattern being used in higher mobility scenarios (for example, as shown in Figure 17), while a lower density pattern is used in low to medium mobility.

[0153] The type of distributed DM-RS pattern can be dynamically configured by the eNB. For example, several distributed DM-RS patterns, e.g., "none," "low density," and / or "high density," may be defined. In DL transmissions, the pattern type may be signaled by the eNB to the WTRU within the control channel, for example in the DCI, and the pattern may be applied to the DL assignment associated with that DCI. In UL transmissions, the pattern type may be dynamically configured by the eNB via the DL control channel. In this case, the WTRU may apply the pattern to the transmission indicated by the UL authorization (e.g., subframe / TTI).

[0154] In DL and UL transmissions, the configured DM-RS pattern can be cell-specific or WTRU-specific.

[0155] When distributed DM-RS is enabled, some of the time / frequency resources may need to be taken from data transmission and allocated to DM-RS transmission. The transport block size may be kept constant regardless of the type of configured distributed DM-RS pattern, for example, to accommodate a different number of available resource elements (REs), and / or the rate matching pattern may be defined to be associated with each distributed DM-RS pattern type. For example, when configured for a high-density distributed DM-RS pattern type, the WTRU may select the corresponding rate matching pattern to apply (for example, for signaled TBS). The rate matching pattern may be kept the same (regardless of the DM-RS pattern type), and different sets of transport block sizes may be defined and associated with each distributed DM-RS pattern type. Based on the selected DM-RS pattern type, the corresponding TBS table may be used.

[0156] In a system using non-orthogonal multiple access (NOMA), where several WTRUs may be assigned for transmission within the same time / frequency resources, the same distributed DM-RS pattern type may be configured for WTRUs in the same NOMA group (e.g., all WTRUs) to prevent collisions between data and RS, for example. WTRUs in that NOMA group may be configured with the same distributed DM-RS pattern type either through individual signaling of WTRU-specific DM-RS patterns, or using a group ID (such as group RNTI) that simultaneously constitutes all WTRUs in the group (e.g., all WTRUs).

[0157] PNRS and DM-RS may be associated. One or more DM-RS ports may be used for PDSCH or PUSCH transmissions. The number of DM-RS ports used for PDSCH or PUSCH transmissions may be determined based on the number of layers used for, allocated for, or determined for, PDSCH or PUSCH transmissions, where the number of layers may be referred to as the transmission rank. One or more of the following may apply: the number of layers for PDSCH or PUSCH transmissions may be indicated in the associated DCI; the presence and / or PNRS density may be determined based on the number of layers indicated for PDSCH or PUSCH transmissions; the presence and / or PNRS density may be determined based on one or more scheduling parameters that do not include the number of layers; and / or the number of PNRS ports (or PNRS density) may be determined based on the number of codewords used for, scheduled for, or determined for, WTRUs.

[0158] The number of layers for PDSCH or PUSCH transmission may be indicated in the associated DCI. The set of DM-RS ports may be determined based on one or more of the following: the number of layers, the indication of MU-MIMO operation, the indication of the set of DM-RS ports associated with the number of layers, or the indication of the set of DM-RS ports. The number of OFDM symbols used for DM-RS may be determined based on the indicated number of layers.

[0159] The presence and / or density of PNRS may be determined based on the number of layers indicated for PDSCH or PUSCH transmission. For example, one or more of the following may apply: If the number of layers is lower than a predetermined threshold, a single PNRS port may be transmitted or used; if the number of layers is higher than a predetermined threshold, two or more PNRS ports may be transmitted or used. The number of PNRS ports may be transmitted or used as the number of DM-RS ports, a one-to-one mapping between PNRS ports and DM-RS ports, where the mapped DM-RS ports and PNRS ports may be considered quasi-collocated with respect to at least one of the QCL parameters (e.g., delay spread, Doppler spread, frequency shift, mean received power, spatial Rx parameter, etc.).

[0160] The presence and / or density of PNRS may be determined based on one or more scheduling parameters, not including the number of layers. A single PNRS port may transmit or be used. A PNRS port may be associated with (or QCLed) a certain DM-RS port. The DM-RS ports associated with a PNRS may be predetermined, predetermined, or indicated in the associated DCI. For example, the first DM-RS port in a set of DM-RS ports used for WTRU may be associated with a PNRS.

[0161] The number of PNRS ports (or PNRS density) may be determined based on the number of codewords used for, scheduled for, or determined for the WTRU. For example, if a WTRU is scheduled for a single codeword, one PNRS port may be used; on the other hand, if a WTRU is scheduled for two codewords, two PNRS ports may be used. The number of codewords may be determined based on the number of layers indicated in the DCI. The number of codewords may be determined based on the number of DCIs that a WTRU may receive. For example, a WTRU may receive one or more DCIs, and each DCI may be associated with a codeword. The presence and / or density of PNRS for each codeword may be determined based on one or more of the scheduling parameters for each codeword. A WTRU may receive two DCIs for PDSCH transmissions, and the DCIs may be associated with codewords, including the scheduling parameters for each codeword. The presence and / or density of PNRS for each codeword may be determined based on one or more of the selected MCS level, the number of scheduled PRBs, the number of layers, and the DM-RS density for each codeword. The presence and / or density (including a density of 0) of PNRS for a codeword may be determined based on the QCL status between DM-RS of one or more codewords. For example, if the DM-RS of a scheduled codeword is QCLed and PNRS may be transmitted in a subset of the codeword (e.g., only a single codeword contains PNRS), but the DM-RS of a scheduled codeword is not QCLed, the presence and / or density of PNRS may be determined based on the associated DCI or codeword scheduling parameters.

[0162] In the example, one or more PNRSs may be transmitted or received, and (for example, each) PNRS may be associated with a DM-RS port. A PNRS pattern may be used in a PRB (or PRB pair), and all or a subset of scheduled PRBs may contain a PNRS pattern. A PNRS (or PNRS pattern, PNRS port) in a PRB may be associated with (or QCLed with) a DM-RS port or a set of DM-RS ports, and which DM-RS port or set of DM-RS ports is associated with a PNRS in a PRB may be determined based on one or more of the number of layers (or the number of DM-RS ports), the number of scheduled PRBs (or the scheduled bandwidth), the number of PNRS ports (or the number of subcarriers used for PNRS in a PRB), and / or the PRB index or the PRB location (nth PRB) in the scheduled PRB.

[0163] UCI can be transmitted over PUSCH with or without data. UCI may include at least one of the following: channel status information (e.g., CQI, PMI, RI, and CRI) and HARQ-ACK information (e.g., ACK or NACK). One or more channel status information (CSI) types may be used. CSI types may be associated with CSI parameters. CSI parameters may include one or more of the following: CQI (Channel Quality Indicator), broadband CQI, subband CQI, CQI for a first codeword, and / or CQI for a second codeword; PMI (Precoding Matrix Indicator), broadband PMI, subband PMI, PMI for a first component codebook (e.g., i1), PMI for a second component codebook (e.g., i2); multicomponent codebook structure W1W2 (e.g., W1 may be a first component codebook and W2 may be a second component codebook); CRI (e.g., CSI-RS Resource Indicator); RI (Rank Indicator); and / or PTI (Precoding Type Indicator).

[0164] One or more HARQ-ACK information types may be used. A HARQ-ACK information type may be associated with several HARQ-ACK bits and / or code block groups (CBGs). For example, a HARQ-ACK information type may be associated with a single-bit HARQ-ACK. A HARQ-ACK information type may be associated with a two-bit HARQ-ACK. A HARQ-ACK information type may be associated with a code block group (CBG). A HARQ-ACK information type may be associated with a transport block. A transport block may have one or more CBGs.

[0165] One or more UCIs may be used. A UCI portion may include one or more CSI types and / or HARQ-ACK information types. UCIs may be coded separately and transmitted simultaneously. A first UCI portion may include one or more CSI types. A first UCI portion may have a constant payload size regardless of the values ​​that may be determined for one or more CSI types. For example, CRI, RI, PTI, and CQI for a first codeword may be a first UCI portion. A second UCI portion may include one or more CSI types. A second UCI portion may have a variable payload size that may depend on one or more CSI values ​​in the first UCI portion. For example, PMI and CQI for a second codeword may be a second UCI portion, and its payload size may be determined based on the RI value of the first UCI portion. A third UCI portion may include one or more HARQ-ACK information types.

[0166] One or more PTRS patterns and / or PTRS types may be used. The PTRS pattern and / or PTRS type for a PUSCH transmission may be determined based on the number of REs required for a UCI transmission or at least one of the specific UCI parts being transmitted.

[0167] The PTRS pattern and / or PTRS type for a PUSCH transmission may be determined based on the number of REs required for a UCI transmission (Nre). For example, if Nre is less than a predetermined threshold (α), a first PTRS pattern may be used; otherwise, a second PTRS pattern may be used. Two or more thresholds may be used with multiple PTRS patterns. Nre may be associated with a specific UCI portion. For example, Nre may be counted only for a subset of a UCI portion (e.g., the first or third UCI portion). The PTRS pattern may be determined based on the ratio of Nre to the available REs for a PUSCH transmission (e.g., Npusch). For example, if the Nre / Npusch ratio is less than a predetermined threshold, a first PTRS pattern may be used; otherwise, a second PTRS pattern may be used. The ratio may be determined based on Nre / Npusch or Npusch / Nre. Npusch may be the number of available REs for a PUSCH transmission. The available REs may not include one or more of the reference signals (e.g., DM-RS and SRS) and UCI Res. Npusch can be the nominal number of REs. The nominal number of REs may be determined based on the scheduled bandwidth and / or TTI length (or slot length).

[0168] Table 1 shows an example of determining the PTRS pattern based on at least one of Nre or Nre / Npusch. The determination of the PTRS pattern may be based on the number of REs required for UCI (Nre) and / or the ratio between Nre and the number of REs available for PUSCH transmission.

[0169] [Table 1]

[0170] The PTRS pattern and / or PTRS type for a PUSCH transmission may be determined based on the specific UCI portion being transmitted. For example, if a first UCI portion and / or a second UCI portion is transmitted over PUSCH, the first PTRS pattern may be used; if a third UCI portion is transmitted over PUSCH, the second PTRS pattern may be used. The PTRS pattern may differ if a set of UCI portions is transmitted over PUSCH. The PTRS pattern may be determined based on whether the UCI contains a HARQ-ACK information type. For example, if the HARQ-ACK information type is not included in the UCI, the first PTRS pattern may be used; otherwise, the second PTRS pattern may be used for the PUSCH transmission. The PTRS pattern and / or PTRS type for a PUSCH transmission may be determined based on the presence of a UCI in the PUSCH transmission. For example, if UCI is present on the PUSCH transmission, a first PTRS pattern (e.g., a first PTRS density) may be used, and if UCI is not present on the PUSCH transmission, a second PTRS pattern (e.g., a second PTRS density) may be used.

[0171] Table 2 shows an example of PTRS pattern determination based on the transmission of UCI portions over PUSCH. PTRS pattern determination may be based on the presence of one or more UCI portions within PUSCH.

[0172] [Table 2]

[0173] Sounding Reference Signal (SRS) transmissions are disclosed. Sounding Reference Signal (SRS) transmissions may include one or more of subband SRS or SRS transmissions and RE mutes for SRS.

[0174] Figures 18 and 19 show an example of a Tx / Rx beam sweep based on SRS. Figure 20 shows an example of an SRS transmission for beam measurement. Figure 21 shows an example of an SRS transmission using subband hopping.

[0175] Subband SRS is disclosed. A common design for CSI-RS and SRS may be beneficial, as the same waveform may be used for DL ​​and UL (e.g., in NR). A sounding reference signal may be used for channel quality estimation and / or beam measurement. Multishot SRS transmission may be used, as the number of transmitter and receiver beams being measured may be multiples. Multishot may mean that an SRS (e.g., a set of SRSs) may be transmitted over a set of OFDM symbols that may be a sequence of OFDM symbols and / or may follow a sequence or pattern over a time (and / or frequency) that may be composed, determined, and / or known. The SRSs transmitted within each of the OFDM symbols may be the same or different. As an example, in Figure 18, the WTRU is transmitting the same SRS, while the eNB is sweeping its received beam, and in Figure 19, the WTRU is sweeping its SRS, for example, the WTRU is sweeping the beam it uses for transmitting the SRS.

[0176] A sequence or pattern may be constructed or determined with respect to at least one of symbols, slots (e.g., time slots), and / or mini-slots. A sequence or pattern may be a function of burst time, e.g., burst time of a beam or synchronization signal, time window (e.g., beam time window), or time block (e.g., beam time block). A burst time, time block, or time window may be a time quantity (e.g., a continuous quantity of time). A burst time, time block, or time window may be a time quantity (e.g., a continuous quantity of time) over which a beam direction may be used for transmission or reception. For example, the direction may not change during a burst time, time window, or time block, except possibly for transition times at the beginning and / or end of the burst time, time window, or time block.

[0177] For example, a WTRU may transmit a multishot SRS. A multishot SRS can be a set of SRSs transmitted within one or more symbols in each of a set of burst time, time window, or time block. The transmission may follow a configuration that may be given by an eNB (e.g., a gNB, eNBs and gNBs can be used interchangeably) or other network entity.

[0178] A WTRU may not be able to transmit SRS across the entire bandwidth due to power limitations, for example. It may be preferable for a WTRU to transmit SRS over subbands during a given time interval and to time-multiplex the transmission of SRS over different subbands. For example, in Figure 20, the SRS is transmitted over the same subband to enable beam measurements, while in Figure 21, the SRS is transmitted over different subbands to sound a larger bandwidth.

[0179] The beam measurement reference signal (BRS) may be configured to be a special case of downlink CSI-RS and uplink SRS. For example, the BRS may be configured to be a CSI-RS or SRS transmitted on a particular antenna port. Resource allocation for the BRS (and / or SRS) may be defined by time and / or frequency resource allocation and may be configured by the eNB.

[0180] SRS transmission and RE mute for SRS are disclosed. Resource elements (REs) may be time and / or frequency resources or sets of time and / or frequency resources, or corresponding thereto. For example, an RE may be a set of symbols (e.g., one or more symbols) and a set of frequencies or subcarriers (e.g., N frequencies or subcarriers), or corresponding thereto. Frequencies or subcarriers may be a transmission band or a subset of frequencies or subcarriers within a bandwidth.

[0181] SRS can be transmitted, for example, in a set of REs that can be distributed across the system bandwidth or across subbands of the system bandwidth by a WTRU. SRS can be transmitted in one or more symbols that may or may not be temporally adjacent. In one example, an RE may correspond to one symbol and N subcarriers. SRS can be transmitted in a set of REs that can constitute the RE being transmitted.

[0182] For example, a WTRU may receive a configuration of one or more, e.g., S sets of REs that may be transmitted by a WTRU (e.g., a first WTRU) and / or another WTRU (e.g., a second WTRU). The configuration of a set of REs may include identification information for the set of REs in a band or subband. The configuration of a set of REs may include identification information for the set of REs in a portion of a band or subband that may be repeated in the band or subband.

[0183] A set of S REs, for example, a set of REs that can be used for SRS transmission during a time period (e.g., a subframe or TTI), such as the current or next time period; the number of symbols (e.g., consecutive symbols) that can be transmitted in an SRS (e.g., a multi-shot SRS) (e.g., the number of symbols can consist of one or more sets (e.g., for each set individually) or once for all sets or subsets of sets)); the interval (e.g., in time or symbol units) between symbols for a multi-shot transmission; the burst time between SRS transmissions or sets of SRS transmissions. Intervals in time blocks or time windows, for example, patterns of burst times, time blocks or time windows for an SRS transmission that allow a WTRU to determine burst times, time blocks and / or time windows while transmitting an SRS (for example, transmitting an SRS in one or more symbols), or at least one of the following can be configured or indicated (for example, a WTRU can receive configuration or indication of at least one of them): intervals in time blocks or time windows, for example, burst times, time blocks or / or time windows for an SRS transmission, or whether it changes its transmit beam or direction (e.g., sweeps) during an SRS transmission (e.g., during a multi-shot SRS transmission).

[0184] A subframe may be used herein as an example of a unit of time. Other units may be used and still be consistent with this disclosure. For example, in the examples described herein, a slot (e.g., a time slot) or mini-slot may be replaced with a subframe and still be consistent with this disclosure.

[0185] RE sets can be constructed with periodicity.

[0186] Configuration or indication may be given semi-statically by physical layer signaling (e.g., via higher layer signaling such as RRC signaling), or dynamically (e.g., by eNB) and / or received (e.g., by WTRU), for example, in DL control information (DCI) or with authorization such as UL authorization.

[0187] A WTRU may receive an indication (e.g., a trigger) to send an SRS (e.g., dynamically). An indication is sometimes referred to herein as an SRS trigger. For example, an SRS trigger may be given and / or received (e.g., by an eNB) in or using a UL authorization. An SRS trigger may be received in DL control information (DCI), for example, a UL authorization or in a DCI format that may contain one. A WTRU may transmit an SRS based on the receipt of an SRS trigger. A WTRU may transmit an SRS on the UL channel (e.g., PUSCH) on which the authorization was received during a time period (e.g., a subframe or TTI) during which the WTRU can transmit.

[0188] A WTRU may receive an indication of at least one set of REs that transmit SRS. The indication of a set may identify which of the S configured sets to use. A WTRU may transmit an SRS on a set of REs based, for example, on the receipt of an SRS trigger and the receipt of a set of REs that transmit SRS. A WTRU may transmit an SRS in a configured or indicated symbol.

[0189] For example, a WTRU may receive a configuration of a set of S REs. A WTRU may receive a configuration or indication, for example, in or using a UL authorization, that receives an SRS trigger and transmits an SRS using one or more sets of REs, which may be subsets of the set of S REs. An indication may identify a set of REs by an index or other identifier relating to the set of S REs. An indication may explicitly identify a set of REs.

[0190] A WTRU may receive a UL authorization and / or an SRS trigger during time period n. A WTRU may transmit a PUSCH and / or SRS during time period n+k based on the receipt of a UL authorization and / or SRS trigger during time period n, for example. A WTRU may transmit an SRS on one or more sets of REs when transmitting an SRS during time period n+k, for example. A WTRU may transmit an SRS on one or more sets of REs over multiple symbols (or other time periods), for example, when multi-shot SRS transmissions are used. A hopping pattern may be used such that, for example, when multi-shot SRS transmissions are used, a first set of REs may be used for SRS transmissions over a first symbol or other time period, and a second set of REs may be used for SRS transmissions over a second symbol or other time period. The delay from receiving an SRS trigger for an SRS transmission and the delay from receiving a UL authorization for a PUSCH transmission may be the same or different.

[0191] If an SRS transmits (e.g., a signal or channel) during the time period in which it is transmitted, the WTRU may mute its transmission in the RE that may be used for the SRS transmission. The WTRU may mute its transmission by rate matching around the RE that may be used for the SRS transmission.

[0192] A WTRU may rate match around a RE used for SRS in a symbol, for example. For example, if a WTRU transmits (e.g., a channel or signal) in a symbol used for SRS by that WTRU or another WTRU, the WTRU may rate match its transmission around the RE used for SRS. For example, a WTRU may rate match a data channel (e.g., PUSCH) transmission or a control channel (e.g., PUCCH) transmission around an RE used for SRS transmission. PUSCH and PUCCH may be used as examples of channels that a WTRU may transmit. Another channel may be used in accordance with this disclosure.

[0193] A WTRU can rate-match around REs in a set of REs that it may use for SRS transmission. For example, if a WTRU receives both a UL authorization and an SRS trigger, it may transmit a PUSCH and an SRS within the same time period. If it transmits a PUSCH, the WTRU may rate-match around one or more sets of REs that it may use for SRS transmission.

[0194] Rate matching around a set of REs (e.g., rate matching transmits) may mean not mapping coded bits (e.g., of a transmit) to a set of REs. For example, if coded bits of a PUSCH are mapped to an RE during a certain time period, a WTRU may skip REs that are used for SRS transmits during that time period (e.g., a WTRU or another WTRU might use for an SRS transmit). The time period could be, for example, a symbol or a subframe.

[0195] The first WTRU may receive a configuration of one or more RE sets that the second WTRU may use for SRS transmission during a certain period of time. The configuration may be given in or using the UL authorization received by the first WTRU. The configuration may be given, for example, in DL control information (DCI) or DL ​​control channel. The DCI or DL ​​control information may be separate from the DCI or DL ​​control channel for the UL authorization of the first WTRU.

[0196] The first WTRU may rate match around REs in the set of REs that the second WTRU may use for SRS transmission. The configuration or representation of the set of REs that the second WTRU may use for SRS transmission may be given to and / or received by the first WTRU, for example, in a UL authorization for the first WTRU, together with and / or separately from it.

[0197] In one example, a first WTRU may receive UL authorization to transmit a PUSCH during a time period. The WTRU may receive an indication that at least a second WTRU may transmit an SRS during the same time period. The WTRU may receive a configuration or indication of a set of REs on which at least a second WTRU may transmit an SRS. If a PUSCH is transmitted, the WTRU may rate match around REs that can be used by at least a second WTRU for the SRS.

[0198] The number of bits that can be transmitted per RE can affect, for example, the power that a WTRU may need or can use to transmit a channel or signal such as a PUSCH to achieve a certain or desired performance. The number of REs available for transmission can affect the power that a WTRU may need or can use.

[0199] The first WTRU may determine or adjust its transmit power for a channel or signal (e.g., PUSCH, PUCCH, SRS, transmit power) or for a set of channels and / or signals based on the REs available for transmission. The WTRU may determine the number of available REs and set or adjust the power based on at least the number of available REs.

[0200] One or more of the following REs may be considered, for example, by the first WTRU when determining which REs are available for transmission (for example, during a time period) and / or when determining which REs are available for transmission (for example, during a time period), which REs are unavailable (for example, during a time period), which REs may be used for SRS transmissions, which REs may be used for DMRS by the first WTRU, which REs may be used for UL Control Information (UCI) transmissions when UCI transmissions may be piggybacked over PUSCH transmissions.

[0201] A set of REs that may be deemed unavailable by the first WTRU could, for example, be a set of REs that may be used by the first or second WTRU for another channel or signal.

[0202] WTRU can determine power independently of available REs if, for example, the number of unavailable REs falls below a configured threshold.

[0203] When determining SRS power, the determination may be based on at least the number of REs that can be used for SRS transmission.

[0204] A WTRU may consist of, for example, semi-persistent scheduling (SPS) for UL transmissions. SPS may grant a WTRU permission or allocation of resources within the UL that it can use over multiple periods of time (e.g., multiple slots or subframes) without receiving additional permission (e.g., for new data). During some of those time periods, at least some of the resources used for or allocated to the SPS transmission may be used by a WTRU (e.g., another WTRU) for SRS.

[0205] An example of SRS transmission and RE-mute is shown in Figure 22. The first WTRU may receive an SRS configuration that can be used for SRS transmission by the first WTRU or the second WTRU.

[0206] A first WTRU may receive an indication that another (for example, a second) WTRU may transmit SRS according to an SRS configuration, such as the SRS configuration described herein. The SRS configuration may, for example, provide a set of symbols and / or REs. The SRS configuration may, for example, provide a time and / or frequency pattern.

[0207] The first WTRU may transmit over a UL (e.g., a UL data channel such as PUSCH). The first WTRU may, for example, mute (e.g., blank) one or more REs and / or symbols that another WTRU may transmit SRS to, according to a configuration that the first WTRU may receive, e.g., an SRS configuration, and / or rate match around them.

[0208] The first WTRU may receive indications that may indicate when SRS configuration, mute, and / or rate matching may be activated and / or deactivated. The first WTRU may receive indications that may indicate when it should perform mute or rate matching, and / or when it should not perform mute and / or rate matching. These indications may be received in at least one of RRC signaling, MAC signaling, or physical layer signaling.

[0209] SRS configurations, mutes, and / or rate matching may be activated and / or deactivated, for example, based on received indications. SRS configurations, mutes, and / or rate matching may be for a particular UL transmission (e.g., an SPS configuration), for a duration, for a time window, and / or until deactivated. A particular UL transmission, duration, and / or time window may relate to when the activation request was received, for example, to a time unit n+k for an activation request received during time unit n.

[0210] Activate / Deactivate can be used to represent activation and / or deactivation. Enable and activate can be used interchangeably. Disable and deactivate can be used interchangeably.

[0211] In the example, SRS configuration, mute, and / or rate matching activation / deactivation may be given during MAC-CE. In the example, SRS configuration, mute, and / or rate matching activation / deactivation may be given during physical layer signaling, such as during a DCI format configured for and / or associated with an SPS configuration or transmission, (for example, its CRC may be scrambled) using C-RNTI (e.g., SPS C-RNTI).

[0212] WTRU may mute one or more resources (e.g., RE and / or symbols) and / or rate match around them based on or in response to receiving an activation or indication for at least one of SRS configuration, resource mute, and / or SRS rate matching around.

[0213] Semi-permanent SRS may be offered.

[0214] A WTRU may transmit SRS, for example, multi-shot SRS, and / or be configured to do so. A WTRU may receive configurations for SRS transmission. A WTRU may receive activations and / or deactivations for SRS transmission.

[0215] A WTRU may, for example, transmit an SRS according to at least the configuration it has received. A WTRU may transmit an SRS in response to receiving an SRS activation, for example, by starting to transmit it. A WTRU may not transmit an SRS in response to receiving an SRS deactivation, for example, by stopping to transmit it.

[0216] In one example, SRS activation and / or SRS deactivation may be given and / or received within a MAC control element (e.g., MAC-CE).

[0217] MAC-CE can be received in the PDSCH. A WTRU that fails to detect a MAC-CE that deactivates SRS transmission may continue transmitting SRS until the gNB recognizes the detection failure and sends another deactivation that can be successfully received, for example, by a WTRU that deactivates SRS transmission.

[0218] The WTRU may consist of a time window or other parameters and / or a time frame during which the WTRU can transmit SRS, for example, to ensure SRS deactivation in cases where deactivation requests may be lost.

[0219] In one example, a WTRU may consist of a duration parameter for SRS transmissions, e.g., D. A WTRU may receive an activation request in, for example, DCI or MAC-CE. A WTRU may transmit SRS until it successfully receives a deactivation request. A WTRU may transmit SRS until a time (e.g., a timer) expires, where the time is based on D. In the example, a WTRU may transmit SRS until it has performed, for example, D (or a function of D) SRS transmissions or a set of SRS transmissions since receiving an activation. A WTRU may stop transmitting SRS after D (or a function of D) SRS transmissions. In the example, a WTRU may stop transmitting SRS after, for example, D (or a function of D) since receiving an activation. D can be a unit of time such as a symbol, slot, minislot, subframe, frame, time burst, or time block.

[0220] The starting point for determining the time window or number of transmissions may be the time or time unit (e.g., subframe, slot, minislot, etc.) at which the SRS activation (e.g., the last or most recent SRS activation) is transmitted (e.g., by a gNB) and / or received (e.g., by a WTRU).

[0221] For example, a WTRU may receive an SRS activation during time unit n (e.g., a subframe, slot, or minislot). The WTRU may begin transmitting SRS during time unit n+k. The SRS during time unit n+k may be considered the first SRS transmission for counting SRS transmissions. Time unit n or n+k may be considered the start time (e.g., time 0) for counting time from the reception of the activation.

[0222] A WTRU may restart its count (e.g., transmission or time) if it receives an activation (e.g., reactivation) request before it stops transmitting an SRS that may have been initiated by a previous activation request. A WTRU may ignore activations (e.g., reactivations) it may receive before it stops transmitting an SRS that may have been initiated by a previous activation request, for example, to avoid the possibility of continuing to transmit due to a misunderstanding of deactivation as activation.

[0223] The duration parameter, which may represent the maximum time window, can be comprised of a broadcast signal or WTRU-specific signaling. For example, the parameter could be provided by RRC signaling. In the example, the parameter could be contained within a MAC-CE, such as a MAC-CE that provides activation and / or deactivation.

[0224] For example, there may be a set of duration parameters, and the configuration may indicate which of the duration parameters in the set to use. One of the duration parameters may indicate infinity or always, which corresponds to, and / or may result in, the WTRU using only deactivation requests to stop SRS transmission after SRS transmission has been activated.

[0225] In the example, deactivation may be indicated by a duration parameter such as 0 (e.g., an activation duration parameter) in MAC-CE or DCI.

[0226] For example, a WTRU may be activated (for example, to transmit an SRS) using a duration parameter such as infinity or always, which can indicate to the WTRU that it will transmit an SRS until it receives deactivation (for example, according to a configuration that may have been received previously). The WTRU may transmit an SRS in response to activation. A WTRU may be activated or deactivated using a duration parameter such as 0, which can indicate that it will stop transmitting an SRS. The WTRU may stop transmitting an SRS in response to activation or deactivation.

[0227] Demodulated reference signal (DM-RS) transmission may be provided. For example, a DM-RS sequence may be mapped to interleaved subcarriers. DM-RS sequences associated with different antenna ports may be multiplexed using orthogonal sequences (e.g., one per antenna port) and / or by spreading them across adjacent OFDM symbols using time-domain orthogonal cover codes (TD-OCC).

[0228] For example, one or more DM-RS configurations may be used, where the DM-RS configuration may be determined based on one or more of the following: the number of subcarriers used in OFDM symbols or DFT-s-OFDM symbols, the orthogonal cover codes (OCCs) in the time domain or frequency domain, the number of cyclic shifts in the DM-RS sequence, and / or the number of symbols (e.g., OFDM symbols or DFT-s-OFDM symbols) used for DM-RS.

[0229] The number of subcarriers used in an OFDM symbol or DFT-s-OFDM symbol can be used to determine the DM-RS configuration. For example, a subset of subcarriers in a PRB may be used, and this subset of subcarriers may be uniformly located within the PRB. For example, a PRB may have 12 subcarriers in an OFDM symbol or DFT-s-OFDM symbol, and a first configuration may use 6 of the 12 subcarriers, located every other subcarrier (e.g., even-numbered or odd-numbered subcarriers), and a second configuration may use 4 of the 12 subcarriers, located every two subcarriers. A subset of subcarriers in a PRB may be used, and this subset of subcarriers may be non-uniformly located within the PRB.

[0230] Orthogonal cover codes (OCCs) in the time domain or frequency domain may be used to determine the DM-RS configuration. For example, an OCC in the time domain (TD-OCC) may be used with two consecutive subcarriers in the time domain (e.g., TD-OCC may use

[0011] and another TD-OCC may use [1-1]), an OCC in the frequency domain (FD-OCC) may be used with two consecutive subcarriers in the frequency domain (e.g., FD-OCC may use

[0011] and another FD-OCC may use [1-1]), a first configuration may use TD-OCC, and a second configuration may use FD-OCC.

[0231] The number of cyclic shifts in the DM-RS sequence can be used to determine the DM-RS configuration. For example, the first configuration may use a cyclic shift of N1, and the second configuration may use a cyclic shift of N2.

[0232] The combinations can be used to determine the DM-RS configuration. For example, a first DM-RS configuration may use K1 (e.g., K1=6) subcarriers, TD-OCCs, and N1 (e.g., N1=4) cyclic shifts in the PRB; a second DM-RS configuration may use K2 (e.g., K2=4) subcarriers, TD-OCCs, and N2 (e.g., N2=2) cyclic shifts in the PRB; a third DM-RS configuration may use K1 (e.g., K1=6) subcarriers, FD-OCCs, and N3 (e.g., N3=0) cyclic shifts, and so on.

[0233] One or more DM-RS configurations, the DM-RS configurations include: subcarrier spacing (if the subcarrier spacing is below a threshold, a first DM-RS configuration may be used (e.g., the DM-RS configuration uses TD-OCC); if the subcarrier spacing is above a threshold, a second DM-RS configuration may be used (e.g., the DM-RS configuration uses FD-OCC)); carrier frequency; NR-PDCCH search space (or NR-PDCCH CORESET) (if the associated DCI is received in the first NR-PDCCH search space (or first NR-PDCCH CORESET), a first DM-RS configuration may be used; if the associated DCI is received in the second NR-PDCCH search space (or second NR-PDCCH CORESET), a second DM-RS configuration may be used. The CORESET may be determined based on one or more of the following: the RNTI of the received DCI (one or more RNTIs may be used for the associated DCI, and the DM-RS configuration may be determined based on the RNTI used for the DCI), the MIMO operating mode (a first DM-RS configuration may be used when the WTRU is configured in a first MIMO operating mode (e.g., SU-MIMO mode), a second DM-RS configuration may be used when the WTRU is configured in a second MIMO operating mode (e.g., MU-MIMO mode), and the MIMO mode operation may be determined based on the associated DCI type), and / or the mobility of the WTRU (e.g., the speed of the WTRU).

[0234] An implicit DM-RS configuration determination for IFDMA-based DM-RS may be provided. Figure 23 shows an example of port multiplexing using IFDMA with orthogonal sequences and repetitions. Two exemplary configurations may be as follows:

[0235] For example, a DM-RS sequence for an antenna port may be mapped to every k-1 subcarriers. As an example, in Figure 23, a DM-RS sequence is mapped to every other subcarrier in an OFDM symbol. To multiplex multiple ports on the same resource, up to K different sequences may be mapped onto the same subcarrier. These K sequences may be orthogonal. The same DM-RS symbol may be repeated on adjacent OFDM symbols. This may be the specified configuration 1 for simplicity of explanation.

[0236] For example, a DM-RS sequence for an antenna port may be mapped to every k-1 subcarriers. As an example, in Figure 23, a DM-RS sequence is mapped to every other subcarrier in an OFDM symbol. To multiplex multiple ports on the same resource, up to M different sequences may be mapped onto the same subcarrier. The M sequences may be orthogonal. This may be the given configuration 2 for simplicity of explanation. In this option, symbols from two different DM-RS sequences may be transmitted on the same subcarrier across several adjacent OFDM symbols using orthogonal cover codes. For example, (assuming two OFDM symbols,) on subcarrier k, r1

[0011] and r2[1-1] may be transmitted across the two OFDM symbols, for example, subcarrier k on the first OFDM symbol is loaded with r1+r2, and the same subcarrier on the second OFDM symbol is loaded with r1-r2. In this example, r1 and r2 may be coefficients of the DM-RS sequence.

[0237] If the channel on subcarrier k changes significantly from one OFDM symbol to another, orthogonality loss can occur, and r1 and r2 may not be completely separated in the receiver. This could be due to phase noise, for example, since phase noise can change from one OFDM symbol to another. The effect of phase noise can be greater at higher frequencies. Similarly, high mobility can result in orthogonality loss.

[0238] The configuration for DM-RS transmission may be implicitly determined by one or more of the following. The configuration can be generalized such that one configuration (Configuration 1) can be a DM-RS configuration that does not use time-domain cover spreading, while another configuration (Configuration 2) can be a DM-RS configuration that uses a time-domain cover code applied over several adjacent OFDM symbols.

[0239] Carrier frequency (fc): When fc ≥ Fc, Configuration 1 can be used; when fc < Fc, Configuration 2 can be used.

[0240] Subcarrier spacing (Δf): When Δf ≥ F, Configuration 1 can be used; when Δf < F, Configuration 2 can be used.

[0241] Speed (v): When v ≥ V, Configuration 1 can be used; when v < V, Configuration 2 can be used.

[0242] The parameters Fc, F, and V can be configured by the gNB or the network.

[0243] An implicit determination of the DM-RS configuration for FDMA-based DM-RS can be provided. In a possible DM-RS configuration, DM-RS ports can be multiplexed over adjacent subcarriers using frequency-domain orthogonal cover codes. Two exemplary configurations, one using and one not using a time-domain cover code, can be as follows.

[0244] FIG. 24 shows an example of FDM of DM-RS symbols without using a time-domain cover code. The DM-RS ports can be multiplexed across adjacent subcarriers using frequency-domain orthogonal cover codes, such as

[0011] and [1 -1]. Adjacent OFDM symbols can be used to transmit different DM-RS symbols of different DM-RS ports. For example, if the DM-RS symbols for four ports are a, b, c, d, the transmitted symbols are shown in FIG. 24. This can be the specified configuration 1 for simplicity of explanation.

[0245] FIG. 25 shows an example of FDM of DM-RS symbols using a time-domain cover code. The DM-RS ports can be multiplexed across adjacent subcarriers using a frequency-domain orthogonal cover code. On top of this, the time-domain cover code can be used to spread the reference symbols across adjacent OFDM symbols. For example, if the DM-RS symbols for four ports are a, b, c, d, the transmitted symbols are shown in FIG. 25. This can be the specified configuration 2 for simplicity of explanation.

[0246] The configuration for DM-RS transmission can be implicitly determined by one or more of the following methods. These options can be generalized such that one configuration (configuration 1) can be a DM-RS configuration without using a time-domain cover code, while another configuration (configuration 2) can be a DM-RS configuration using a time-domain cover code applied across several adjacent OFDM symbols. When the carrier frequency (fc): if fc≧Fc, configuration 1 can be used; if fc<Fc, configuration 2 can be used. Subcarrier spacing (Δf): if Δf≧F, configuration 1 can be used; if Δf<F, configuration 2 can be used. Speed (v): if v≧V, configuration 1 can be used; if v<V, configuration 2 can be used. The parameters Fc, F, V can be configured by the gNB or the network.

[0247] Figure 26 shows an example of PNRS frequency density for QPSK, 16QAM, and 64QAM modulation.

[0248] Figure 27 shows an example of determining the frequency density for PNRS transmission. A subset of PRBs for PNRS transmission may be based on WTRU ID (for example, to randomize multi-user interference). The PNRS frequency density may be based on the MCS level (for example, 16QAM may have a density of 1, 64QAM may have a density of 2).

[0249] While features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multipurpose disks (DVDs). Processors related to software may be used to implement radio frequency transceivers for use in WTRUs, WTRU terminals, base stations, RNCs, or any host computer.

[0250] While the features and elements of this specification may be considered specific to protocols such as LTE, LTE-A, New Radio (NR), or 5G, it should be understood that the solutions described herein are not limited to these scenarios and may be applicable to other wireless systems as well.

Claims

1. A wireless transceiver unit (WTRU), Memory and Upon receiving an indication that the WTRU is transmitting one or more phase noise reference signals, The system receives scheduling information including a display of the set of uplink resources and a display of the modulation coding scheme, and the set of uplink resources corresponds to a plurality of resource blocks (RBs), The phase noise reference signal density for the transmission of one or more phase noise reference signals is determined, and the phase noise reference signal density is determined at least based on the representation of the modulation coding scheme. The phase noise reference signal pattern for the transmission of one or more phase noise reference signals is determined, and the phase noise reference signal pattern is determined based on the number of groups of phase noise reference signals to be transmitted and the number of phase noise reference signal samples for each group. A first subset and a second subset of the set of uplink resources are determined, the first subset of the set of uplink resources is used for transmitting the one or more phase noise reference signals, the second subset of the set of uplink resources is used for transmitting data associated with uplink transmissions, the first subset of the set of uplink resources is included in a subset of the plurality of RBs, and the subset of the plurality of RBs including the first subset of the set of uplink resources is determined based on at least the WTRU-ID. Uplink transmission is transmitted using the first subset of the set of uplink resources and the second subset of the set of uplink resources. A processor that executes instructions from the memory A WTRU characterized by having the following features.

2. The WTRU according to claim 1, characterized in that the number of groups of phase noise reference signals corresponds to the number of chunks of phase noise reference signals.

3. The WTRU according to claim 1, wherein the scheduling information is received in an uplink permission message, and the uplink permission message includes a representation used by the WTRU to determine the subset of the plurality of RBs, which includes the first subset of the set of uplink resources.

4. The WTRU according to claim 1, characterized in that the phase noise reference signal density is a time density.

5. The WTRU according to claim 1, characterized in that if the level of the modulation coding scheme is greater than a first threshold, the phase noise reference signal density is determined to be a first density for the uplink transmission.

6. The WTRU according to claim 1, characterized in that the uplink transmission is a physical uplink shared channel (PUSCH) transmission.

7. The WTRU according to claim 6, characterized in that the modulation coding scheme of the display is associated with the PUSCH transmission.

8. A method performed by a Wireless Transceiver Unit (WTRU), The WTRU receives an indication that it is transmitting one or more phase noise reference signals, Receiving scheduling information including a display of a set of uplink resources and a display of a modulation coding scheme, wherein the set of uplink resources corresponds to a plurality of resource blocks (RBs). Determining the phase noise reference signal density for the transmission of one or more phase noise reference signals, wherein the phase noise reference signal density is determined at least based on the representation of the modulation coding scheme. Determining a phase noise reference signal pattern for the transmission of one or more phase noise reference signals, wherein the phase noise reference signal pattern is determined based on the number of groups of phase noise reference signals to be transmitted and the number of phase noise reference signal samples for each group. Determining a first subset and a second subset of the set of uplink resources, wherein the first subset of the set of uplink resources is used for transmitting the one or more phase noise reference signals, the second subset of the set of uplink resources is used for transmitting data associated with uplink transmissions, the first subset of the set of uplink resources is included in a subset of the plurality of RBs, and the subset of the plurality of RBs including the first subset of the set of uplink resources is determined based on at least the WTRU-ID. Transmitting an uplink transmission using the first subset of the set of uplink resources and the second subset of the set of uplink resources. A method characterized by comprising:

9. The method according to 8, characterized in that the number of groups of phase noise reference signals corresponds to the number of chunks of phase noise reference signals.

10. The method according to 8, wherein the scheduling information is received in an uplink permission message, and the uplink permission message includes a representation used by the WTRU to determine the subset of the plurality of RBs, which includes the first subset of the set of uplink resources.

11. The method according to 8, characterized in that the phase noise reference signal density is a time density.

12. The method according to 8, characterized in that if the level of the modulation coding scheme is greater than a first threshold, the phase noise reference signal density is determined to be a first density for the uplink transmission.

13. The method according to 8, characterized in that the uplink transmission is a physical uplink shared channel (PUSCH) transmission.

14. The method according to 13, characterized in that the modulation coding scheme of the display is associated with the PUSCH transmission.

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