Reference signal design for wireless communication system

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 wireless communication systems. [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 400,925, filed September 28, 2016, U.S. Provisional Patent Application No. 62 / 454,617, filed February 3, 2017, U.S. Provisional Patent Application No. 62 / 519,424, filed June 14, 2017, and U.S. Provisional Patent Application No. 62 / 556,146, filed September 8, 2017, which are incorporated by reference herein as if reproduced in their entireties.

[0003] 3GPP is working on an advanced wireless communication system, sometimes called New Radio (NR). NR applications can be summarized under several categories, which may include one or more of Enhanced mobile broadband (eMBB), Massive machine-type communications (mMTC), or / and Ultra-reliable-and-low-latency communications (URLLC). Under a category, there may be a broad set of applications considered for various needs and deployment scenarios that may require specific performance requirements. For example, mMTC and URLLC applications may range from the automotive industry to health, agriculture, utilities, and logistics industries.

[0004] In mMTC applications, the system provides up to 1000 km of coverage 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 may be lower (e.g., significantly lower). In URLLC, target delays of less than 1 ms and / or 10 -5 A high reliability of bit error rate of 0.01 can be a target. Summary of the Invention

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

[0006] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which:

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

[0008] 1A illustrates an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides multiple wireless users with content, such as voice, data, video, messaging, broadcasts, etc. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), etc.

[0009] 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, 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 industrial and / or automated processing chain contexts), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c and 102d may be referred to interchangeably as a UE.

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

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

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

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

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

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

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

[0017] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi®)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0018] The base station 114b in FIG. 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a workplace, a home, a vehicle, a premises, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0019] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, error resilience requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, charging services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0020] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs that may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0021] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based radio technology, and with a base station 114b, which may employ an IEEE 802 radio technology.

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

[0023] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, other types of integrated circuits (ICs), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although FIG. 1B illustrates the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

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

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

[0026] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

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

[0028] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, 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) regarding 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 over the air interface 116 from base stations (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location determination method while remaining consistent with an embodiment.

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

[0031] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference either through hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception).

[0032] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As mentioned above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0033] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be appreciated that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0034] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG 1C, the eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0035] 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the above elements is shown as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0036] The MME 162 may be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0037] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during handover between eNodeBs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0038] The SGW 164 may be connected to a PGW 166 that may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0039] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional fixed communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0040] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, it is contemplated that in some representative embodiments such a terminal may use (e.g., temporarily or permanently) a wired communications interface with the communications network.

[0041] In an exemplary 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 or interface to a distribution system (DS) or another type of wired / wireless network that carries traffic into and out of the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be sent to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to the respective destination. Traffic between STAs within a BSS may be sent through the AP, e.g., where a source STA may send traffic to the AP and the AP may send traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) a source STA and a destination STA using a direct link setup (DLS). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all of the STAs) in or using an IBSS may communicate directly with each other. The IBSS communication mode is sometimes referred to herein as an "ad-hoc" communication mode.

[0043] When using an 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In some representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In CSMA / CA, STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back off. One STA (e.g., only one station) may transmit at a given time in a given BSS.

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

[0045] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, sometimes referred to as an 80+80 configuration. In the 80+80 configuration, the data may be passed through a segment parser that may split the data into two streams after channel encoding. Inverse Fast Fourier Transform (IFFT) processing and time domain processing may be performed separately for each stream. The streams may be mapped onto two 80 MHz channels and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be sent to the Medium Access Control (MAC).

[0046] Sub-1 GHz operation modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter-type control / machine-type communication such as MTC devices in macro coverage areas. MTC devices may have some capabilities, for example, limited capabilities including support of some and / or limited bandwidths (e.g., only support). MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0047] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In an 802.11ah example, the primary channel may be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only support) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. The setting of the carrier sense and / or network allocation vector (NAV) may depend on the status of the primary channel. For example, if the primary channel is busy for a STA (that only supports a 1 MHz mode of operation), it may be considered busy to transmit the entire available frequency band to the AP even if most of the frequency band remains idle and may be available for use.

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

[0049] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to one embodiment. As mentioned above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0050] The RAN 113 may include gNBs 180a, 180b, 180c, although it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from, for example, the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multipoint (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or gNB 180c).

[0051] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions related to a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, cells, and / or portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including various numbers of OFDM symbols and / or lasting for varying lengths of absolute time).

[0052] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with / connect to a gNB 180a, 180b, 180c while also communicating with / connecting to another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0053] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interconnection between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another via an Xn interface.

[0054] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the above elements is shown as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0055] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on highly reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services with machine-type communications (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0056] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 115 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and allocating IP addresses for WTRUs, managing PDU sessions, controlling policy enforcement and QoS, providing notification of downlink data, etc. The type of PDU session may be IP-based, non-IP-based, Ethernet-based, etc.

[0057] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks such as the Internet 110 to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0058] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In an embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0059] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-ab, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

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

[0061] The emulation device or devices may perform one or more functions, inclusive, without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation device may be utilized in a test lab and / or in a test scenario in an undeployed (e.g., test) wired and / or wireless communication network to perform tests of one or more components. The emulation device or devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, e.g., one or more antennas) may be used by the emulation device to transmit and / or receive data.

[0062] In LTE, as an 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 with a DFT block and then mapped to corresponding inputs of an IDFT block. The CP may be prepended to the beginning of a symbol to avoid inter-symbol interference (ISI) and enable one-tap frequency domain equalization (FDE) at the receiver.

[0063] In a downlink transmission, reference symbols may be scattered on specific subcarriers, e.g., one OFDM symbol has subcarriers loaded with data and reference symbols. Common reference symbols may be transmitted on subcarriers distributed across the system bandwidth, and / or WTRU-specific reference signals may be distributed on subbands allocated to specific WTRUs.

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

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

[0066] If x is the OFDM symbol after IFFT (e.g., without CP), θt is the phase noise vector of the transmitter, and the received signal after CP removal is

[0067]

number

[0068] It can be written as:

[0069] After the DFT operation in the receiver,

[0070]

number

[0071] where Θt=Fθt and H=Fh. This means that the data vector can be circularly convolved with the phase noise spectrum and the result can be scaled by the channel response. Depending on the spectrum of the phase noise, the data symbols per subcarrier can be rotated with a common phase error and contaminated by inter-carrier interference. The PSD of the phase noise can decay fast and the ICI contributions can be mostly from adjacent subcarriers. In the presence of receiver phase noise,

[0072]

number

[0073] where Θr is the receiver phase noise spectrum.

[0074] A reference signal may be used to compensate for phase noise, and the reference signal may be transmitted over consecutive OFDM symbols in a subframe (or TTI), which may accurately estimate the time-varying phase noise. One or more of the following may apply: the reference signal used to compensate for phase noise may be referred to as 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 downlink signals; or the PNRS may be transmitted in one or more subcarriers in an OFDM symbol, and the same subcarrier may be used in consecutive OFDM symbols within a time window (e.g., see FIG. 2 and FIG. 3 for examples).

[0075] When PNRS is transmitted in one or more subcarriers in an OFDM symbol, and the same subcarrier may be used in consecutive OFDM symbols within a time window, one or more of the following may apply: One or more subcarrier indexes 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), and PNRS collision between adjacent cells may be avoided. 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 transmission (e.g., control, data, and / or broadcast). One or more subcarrier indexes that may be used for PNRS transmission may be predetermined. For example, a center subcarrier in the system bandwidth may be used for PNRS transmission. The number of subcarriers used for PNRS transmission may be indicated from a broadcast signal. The one or more subcarrier indices may be one of the scheduled PRBs and may be a subcarrier index within the PRB that may carry PNRS.

[0076] An example of a PNRS using the same subcarrier locations across consecutive OFDM symbols is shown in Figure 2. An example of a PNRS with unused adjacent subcarriers is shown in Figure 3.

[0077] Lower density PNRS patterns may be defined. For example, these lower density PNRS patterns may be configured by the eNB when the correlation time of the phase noise is longer than the OFDM symbol length. An example of a lower density PNRS pattern is shown in FIG. 4. The density of the PNRS may be determined based on the density in the time domain (e.g., the number of OFDM symbols containing the PNRS in a time window (e.g., slot, subframe, TTI) and / or the density in the frequency domain (e.g., the number of subcarriers used for the PNRS in a system bandwidth, PRB, PRB pair, or scheduled bandwidth)). FIG. 3 shows an example of a PNRS with high density (e.g., in the time domain). FIG. 4 shows an example of a PNRS with low density (e.g., in the time domain), where the lower density PNRS may use a subset of the PNRS transmitted or used for the higher density PNRS.

[0078] The PNRS may be configured for lower or higher density patterns depending on, for example, the numerology (e.g., subcarrier spacing and OFDM symbol duration). For example, in a system operating with a short OFDM symbol duration, a lower density PNRS pattern may be used, for example, when the correlation time of the 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] The subcarrier spacing may be used or configured for unicast traffic (e.g., PDSCH, PUSCH). A set of subcarrier spacings may be used for unicast traffic and one of the subcarrier spacings may be configured or used for PDSCH or PUSCH transmission, for example, the PNRS density may be determined based on the used or configured subcarrier spacing. For example, a set of subcarrier spacings {15, 30, 60, 120, 240} kHz may be used and if the WTRU is configured with subcarrier spacing {15} kHz, PNRS may not be transmitted (e.g., zero PNRS density), and if the WTRU is configured with subcarrier spacing {240} kHz, PNRS with a high density may be used. A set of PNRS densities may be used and a subset of the PNRS densities may be determined based on the used subcarrier spacing. One PNRS density within the subset may 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 spacing may be associated with a subset of PNRS densities. For example, a first subcarrier spacing (e.g., 15 kHz) may be associated with the subset of PNRS densities {PNRS-1}, a second subcarrier spacing (e.g., 30 kHz) may be associated with the subset of PNRS densities {PNRS-1, PNRS-2}, a third subcarrier spacing (e.g., 240 kHz) may be associated with the subset of PNRS densities {PNRS-Nd-1, PNRS-Nd}, etc. The PNRS density subset may be determined based on the determined subcarrier spacing. Within the subset of PNRS densities, one PNRS density may be determined for PDSCH or PUSCH transmission, for example, based on one or more of the scheduling parameters. PNRS-1 may be a zero PNRS density with no PNRS in the scheduled bandwidth.

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

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

[0082] The DM-RS density may be determined based on the presence of additional DM-RS, where the additional DM-RS may be transmitted if configured and / or determined based on one or more of the scheduling parameters. If additional DM-RS are present, a lower density of PNRS may be used, where the lower density of PNRS may not include PNRS (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 referred to as a front-loaded DM-RS, and the additional DM-RS may be located during a 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., a contiguous frequency resource allocation) and a second PNRS density may be used for a second resource allocation type (e.g., a non-contiguous frequency resource allocation).

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

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

[0086] It may be provided to puncture and / or multiplex the PNRS. In the following, 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 systems transmitting using a DFT-s-OFDM waveform. One or more of the following (e.g., features related to those shown in Figures 5 and 6) may apply.

[0088] In an example, puncturing may be provided. FIG. 5 shows an example of pre-DFT PNRS insertion via puncturing. The number of data symbols may match the number of inputs of the DFT. 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 block. As an example, assume that a subframe has 14 OFDM symbols and 24 subcarriers are allocated for data transmission, and thus 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 ½, this may correspond to 336 information bits. If four reference symbols are transmitted per OFDM symbol, 20 QPSK symbols (e.g., only 20 QPSK symbols) may be mapped to the DFT block. The remaining four QPSK symbols may be replaced by reference symbols.

[0089] In an 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 an OFDM symbol may be smaller than the DFT size. After the data symbols are 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 a 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 four inputs of the DFT block may be used by the PNRS.

[0090] The density of PNRS in DFT-s-OFDM using pre-DFT PNRS insertion may be determined based on the number of DFT-s-OFDM symbols containing PTRS, which may be referred to as PNRS time density, and may be determined based on the number of symbols in the data symbol (or data symbol vector) for the DFT input, which may be referred to as 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 DFT-s-OFDM for PUSCH 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 PUSCH 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 one, while a smaller PNRS density may be used when the number of DFT blocks is one. If the scheduled uplink resources are not contiguous in the frequency domain, the number of DFT blocks may be greater than one.

[0091] Chunk-based pre-DFT PTRS insertion may be performed. A PTRS pattern for chunk-based pre-DFT PTRS insertion may be determined based on at least one of the number of PTRS chunks (Nc), the chunk size (Ns), or the location of the Nc chunks in the DFT input (or DFT input signal). FIG. 7 shows an example of a PTRS pattern with Nc and Ns values ​​of the PTRS pattern, where Nc=N chunks with Ns=3 are used. The chunk size (Ns) may be the number of PTRS tones in a chunk. A PTRS tone may be used interchangeably with a PTRS sample, a PTRS RE, and / or a PTRS subcarrier.

[0092] A group of PTRS patterns that may have the same density may be referred to as a PTRS type. PTRS patterns in the same PTRS type may have different Ns and / or Nc values, but the total number of PTRS tones (e.g., Ns x Nc) will be the same. The total number of PTRS tones may be used interchangeably with PTRS density.

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

[0094] In an example, a first PTRS type (e.g., PTRS type-1) may be based on a PTRS density=4. The 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 middle.

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

[0096] PTRS density may 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 may be referred to as the number of PTRS tones for a DFT input and / or the number of DFT-s-OFDM symbols containing a PTRS in a PUSCH transmission. PTRS density may be referred to as the number of PTRS subcarriers in a scheduled bandwidth and / or the number of OFDM symbols containing a PTRS in a PUSCH or PDSCH. A PTRS density (e.g., in the frequency domain, which may be referred to as a PTRS subcarrier) is used for each N scheduled PRBs, where the starting PRB may 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., a parameter configured in a higher layer), a number determined based on a WTRU-specific parameter (e.g., a WTRU-ID, a scrambling ID), and a cell-specific parameter (e.g., a cell ID). The allocated PRBs may be ordered from 0 to Nprb-1 regardless of PRB location, where Nprb may be 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 of the PTRS pattern, and / or PTRS type for the PUSCH 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 the scheduled PUSCH transmission. The numerology may include at least one of the subcarrier spacing, slot length, TTI length, and CP length.

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

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

[0100] The DM-RS configuration may be based on the number of DM-RS symbols (e.g., 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 in 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 in the first DFT-s-OFDM symbol or CP-OFDM symbol 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 a cyclic shift value may be used, where the base PTRS pattern may be determined based on Ns, Nc, or the location of Nc chunks, and a cyclic shifted version of it may have the same Ns and Nc, but the location of the Nc chunks may have an offset (e.g., time offset) from the base PTRS pattern. Figure 8 shows an example of a base PTRS pattern (e.g., CS=0) and its cyclic shifted version of the base PTRS pattern.

[0102] A base PTRS pattern and a cyclically shifted version of the 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, the number of PRBs, the TTI length, the DM-RS configuration, the MCS level, and the transport block size. The cyclic shift value may be determined based on a WTRU-specific parameter or an indicator in the associated DCI.

[0103] The set of cyclic shift values ​​may be configured via higher layer signaling. Additionally or alternatively, the set of cyclic shift values ​​may be determined based on one or more of a base PTRS pattern, a scheduled bandwidth, and / or a frequency location of the scheduled bandwidth.

[0104] The WTRU-specific parameters may include at least one of WTRU capabilities, WTRU category, 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 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] A zero-power PTRS may be used. For example, if the WTRU is scheduled for PUSCH transmission, the WTRU may be indicated to transmit one or more zero-power PTRS. The zero-power PTRS pattern may be determined based on a base PTRS pattern and a cyclic-shifted version thereof. The WTRU may avoid signaling on the RE for the zero-power PTRS.

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

[0107] FIG. 10 illustrates an exemplary WTRU-specific OCC for PTRS tones in a PTRS chunk. An orthogonal cover code (OCC) may be used for the PTRS. For example, an OCC may be used for the PTRS tones in the chunk. The OCC may be used interchangeably with an orthogonal sequence, a random sequence, a PN sequence, a Zadoff-Chu sequence, a scrambling sequence, and / or a Golay sequence. The OCC may be determined based on the chunk size and one or more WTRU-specific parameters. For example, if the WTRU-ID modulo 2 is “0”, a first OCC (e.g.,

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

[0011] ), and if the WTRU is configured with DM-RS port-1, the WTRU may use the second OCC (e.g., [1 -1]). If the OCC is based on the scrambling sequence, initialization of the scrambling 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 systems transmitting using a DFT-s-OFDM waveform. One or more of the following (e.g., features related to those shown in Figures 11 and 12) may apply.

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

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

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

[0112] In an 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 a DFT-s-OFDM transmission may be determined based on one or more of 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] An uplink MIMO transmission mode or scheme 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] The modulation orders may be used. For example, lower modulation orders (e.g., QPSK and 16QAM) may use a first PNRS type / scheme, and 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., polar) may use a second PNRS type / scheme.

[0117] A transport block size may be scheduled, e.g., if the transport block size is greater than a predetermined threshold, a first PNRS type / scheme may be used, and otherwise a second PNRS type / scheme may be used.

[0118] PNRS using OFDM may be provided. Transmission of PNRS may be turned on and off on a user basis. The number of PNRS may be adaptively changed by modulation order and / or other parameters. The number of subcarriers allocated to PNRS may change, which may create a need to adaptively change the transport block size. In an example, the transport block size may be kept constant, for example, when PNRS is turned on or when the number of PNRS is changed. Puncturing may be introduced to map data symbols to available data subcarriers. An example is shown in FIG. 14, which shows an exemplary puncturing in OFDM for PNRS insertion. Data symbols planned to be transmitted on subcarriers carrying PNRS may be punctured and replaced with PNRS, for example, when PNRS has to 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 an OFDM symbol, which inputs of the DFT and / or IDFT are used to feed into PNRS, which OFDM symbols have PNRS) may be configured by a central controller. The number of PNRS symbols in an OFDM symbol may be referred to as the frequency density of PNRS (or the frequency pattern of PNRS), and the number of OFDM symbols having PNRS may be referred to as the time density of PNRS (or the time pattern of PNRS). For example, one or more of the following may be applied for configuration of 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 band, MCS level (e.g., modulation order and / or coding rate), numerology (e.g., subcarrier spacing and / or system bandwidth), higher layer signaling, scheduled bandwidth (or number of scheduled PRBs), number of layers for SU-MIMO transmission (e.g., transmission 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 the PRBs may be used for PNRS transmission. If a subset of the PRBs carries the PNRS, the subset of PRBs carrying the PNRS may be determined based on one or more of a set of DM-RS ports or DM-RS ports allocated or indicated in an associated DCI or WTRU-specific parameters. For example, a set of DM-RS ports or DM-RS ports may be allocated or indicated in an associated DCI for MU-MIMO operation, and the set of PRBs that may carry the PNRS may be determined based on the set of allocated DM-RS ports or 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 include the 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 include the PNRS. WTRU-specific parameters (e.g., WTRU ID, C-RNTI, scrambling identity, scrambling identity of PNRS, etc.) may be provided. For example, a first WTRU may transmit (or receive) every other one of the scheduled PRBs with PRB offset=0, while a second WTRU may transmit (or receive) every other one of the scheduled PRBs with PRB offset=1, where the PRB offsets may be determined based on the WTRU-specific parameters.

[0122] For a scheduled UL transmission, 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 a UL grant. One or more of the following may apply: all RBs allocated for UL transmission (e.g., all RBs allocated for UL transmission) may be configured to carry at least one PNRS (e.g., in the case where PNRS is provided to IDFT); possible patterns may be predefined, e.g., the eNB may signal an index of a desired pattern to the WTRU; 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 grant.

[0123] For scheduled DL transmission, the eNB may signal to the WTRU that a PNRS pattern is to be used during transmission. The eNB may, for example, signal this information to the WTRU along with a DL grant. One or more of the following may apply: RBs allocated for DL ​​transmission (e.g., all RBs allocated for DL ​​transmission) may be configured to carry at least one PNRS (e.g., in the case where PNRS is provided for IDFT); possible patterns may be predefined; for example, the eNB may signal an index of a desired pattern to the WTRU; 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 grant.

[0124] For UL transmission with DFT-s-OFDM, when the PNRS is fed into the DFT block, one or more of the following may apply: A consecutive set of inputs of the DFT may be used to transmit the PNRS, e.g., starting from the smallest index. A consecutive set of inputs of the DFT may be used to transmit the PNRS, starting from the largest index. A set of inputs of the DFT may be used to transmit the PNRS, e.g., where the set of inputs may be determined based on one or more of a predefined location, a WTRU parameter (e.g., WTRU-ID), a service type (e.g., URLLC, eMBB, and mMTC), etc., or a system parameter (e.g., subframe number, radio frame number, cell ID).

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

[0126] The multiplexing and / or puncturing pattern for the PNRS may be determined, for example, implicitly from the 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 (e.g., then) be used for PNRS transmission. The location of the PNRS (e.g., which inputs of the DFT and / or IDFT should be provided during the PNRS) may not be implicitly known and may be preconfigured. For example, the first / last N inputs may be used to transmit the PNRS. The PNRS may be distributed to the allocated resources using a predefined rule (e.g., uniformly, starting from resource index=0).

[0127] For example, if multiplexing of data and PNRS is used, the transport block size (e.g., of a data block 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 and / or PNRS configuration signaled by the eNB. As an example, assuming that 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., a DFT size of N / 2 if DFT-s-OFDM is used). If K resources (e.g., subcarriers) are reserved for PNRS over the duration of a subframe, the actual transport block size may be N−2K information bits. The same may apply to the determination of the transport block size in DL transmission.

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

[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, where a first PNRS configuration may be associated with a downlink control channel and a second PNRS configuration may be associated with a downlink data channel. The PNRS configuration may include one or more of a time / frequency location, an associated transmit / receive point (TRP), a reference signal power, a scrambling code, a scrambling ID, or a periodicity. The first PNRS configuration may be associated with a downlink control channel (e.g., PDCCH) and the second PNRS configuration may be associated with a downlink data channel (e.g., PDSCH). The association between the PNRS configurations and the 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 channel.

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

[0131] One or more PNRS configurations may be transmitted or used for downlink signal transmission, where one or more PNRS may be used to demodulate the downlink signal. An 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 may be scheduled for the WTRU. For PDSCH demodulation, the WTRU may be indicated which PNRS configuration among the multiple PNRS configurations to use. One or more of the following may apply: an associated PNRS configuration for a downlink data channel may be indicated, or an associated PNRS configuration for a control channel may be determined.

[0132] An associated PNRS configuration for a downlink data channel may be indicated by one or more of: an associated DCI that may be used to schedule the PDSCH; a location of the scheduled PDSCH, e.g., a time and / or frequency location of the scheduled PDSCH, may determine the associated PNRS configuration; a location of the DL control channel search space at which the associated DCI is received (e.g., the DL control channel search space (SS) may be partitioned and each partitioned DL control channel search space may be associated with a PNRS configuration, and / or if the WTRU receives a DCI in a partitioned 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 particular PNRS configuration.

[0133] The associated PNRS configuration for the control channel may be determined based on one or more of the following: A DL control search space (SS) may be partitioned, and each partition of the DL control SS may be associated with a particular PNRS configuration. For example, if the WTRU monitors a partitioned DL control SS, the WTRU may use an 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 the (e.g., each) DL control decoding candidate may be associated with a particular PNRS configuration. The associated PNRS for the (e.g., each) DL control decoding candidate may be predetermined, configured, or signaled. The time and / or frequency resources 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. The time / frequency resources for the DL control channel may be referred to as an (E)PDCCH resource set. (E.g., each) (E)PDCCH resource set may be associated with a particular PNRS configuration. The association between the (E)PDCCH resource set and the PNRS configuration may be signaled, configured, or indicated in the (E)PDCCH resource configuration. The PNRS configuration may be pre-configured via higher layer signaling. (E.g., each) PNRS configuration may be associated with an index.

[0134] FIG. 15 shows an example of association of PNRS and EPDCCH resource sets.

[0135] One or more operation modes may be used for demodulation of downlink signals using PNRS. For example, a WTRU may demodulate downlink signals using phase noise compensation based on a cell-specific PNRS in a first operation mode, and the WTRU may demodulate the downlink using phase noise compensation based on the WTRU-specific PNRS. When the WTRU is configured in the first operation mode, the WTRU may use a cell-specific PNRS for downlink signal demodulation, where the cell-specific PNRS may be located in a predefined location. When the WTRU is configured in the second operation mode, the WTRU 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 the PDSCH, and one or more PRBs may be associated with one or more PNRS configurations. In an 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 the phase noise, and a second reference signal (e.g., DM-RS) may be used to estimate the channel, and the estimated phase noise and / or the 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 be different. For example, a single antenna port may be used for the PNRS regardless of the transmission rank (e.g., the number of layers for the downlink signal transmission), and the number of antenna ports for the DM-RS may be determined based on the transmission rank (e.g., the number of layers for the associated downlink transmission). The number of PRBs associated with a PNRS configuration may be indicated, determined, or configured, for example, via higher layer signaling. For example, the WTRU may be configured such that three PRBs may be associated with the PNRS, the WTRU may assume that the PNRS may be transmitted in at least one of the three PRBs associated with the same PNRS, and the WTRU may assume that the PNRS may be transmitted in a subset of the PRBs associated with the same PNRS.

[0137] FIG. 16 shows an example of association of PNRS and PRB sets.

[0138] One or more PRB groups (PRGs) may be used to determine the association between the PRBs and the PNRS. A PRG may be defined as a set of consecutive PRBs in a subframe, and the number 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 include a PNRS. For example, the first PRB in a PRG may include a PNRS. A WTRU may be scheduled on one or more PRBs in a subframe. A WTRU may use a PNRS located in a first PRB of a PRG for demodulation of the PRBs located in the PRG. A PRG may be associated with a TRP (or cell), and (e.g., each) PRG may be associated with a particular TRP (or cell). The number of PRBs for a PRG may be configurable. A PRG size may be the same as the total number of PRBs (e.g., a single TRP is used).

[0139] PNRS transmission may be dynamically turned on and off by the eNB. The WTRU may request transmission of PNRS. PNRS transmission may 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 the PNRS transmission to the WTRU.

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

[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 the PNRS (e.g., one subcarrier, two subcarriers, etc.) may be determined; the UL PNRS may be transmitted in one or more subcarriers within a scheduled uplink resource (e.g., a PRB); the UL PNRS may be transmitted in one or more subcarriers of an OFDM symbol (and in consecutive OFDM symbols of an RB); an index of the subcarrier 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 RBs may carry the PNRS.

[0142] The presence or use of the PNRS may be determined based on the operating frequency band. For example, the UL PNRS may not be used in a lower operating frequency band (e.g., lower than 6 GHz), and the UL PNRS may be used in a higher operating frequency band (e.g., higher than 6 GHz). The WTRU may determine the use or transmission of the PNRS based on the operating frequency band. The use or transmission of the PNRS may be indicated from 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 operating frequency band, the MCS level (e.g., modulation order and / or coding rate), the numerology (e.g., subcarrier spacing and / or system bandwidth), higher layer signaling (e.g., an association between PNRS density and MCS level may be determined based on higher layer signaling and the PNRS density for a 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., transmission rank).

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

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

[0146] The index of the subcarrier within the RB used for UL PNRS transmission may be predetermined, for example, it may be the center subcarrier of the RB. One or more of the following may apply for the UL PNRS subcarrier location (and / or PRB location).

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

[0148] The PNRS may be used to demodulate associated data. For example, a PNRS transmitted in a PRB may be used to demodulate data in the same PRB. One or more of the following may apply: The PNRS may be transmitted in one or more of the PRBs scheduled for the WTRU, and the WTRU (or eNB) may transmit the DM-RS in (e.g., each) PRB, which may be other than the PRB or PRBs containing the PNRS. The DM-RS may be signaled based on a first reference signal pattern (e.g., distributed within the PRB). The PNRS may be signaled based on a second reference signal pattern (e.g., localized within the PRB). The DM-RS location in the PRB or PRBs containing the PNRS may be used for data transmission. For example, if the transmission rank (e.g., number layer) for data is higher than 1, the DM-RS may be transmitted in the PRB or PRBs containing the PNRS. The PNRS may be transmitted in one or more of the PRBs scheduled for the WTRU, and the WTRU (or eNB) may transmit a different type of DM-RS based on the presence of the PNRS in the PRB. For example, if the scheduled PRB includes the PNRS, a first type of DM-RS may be used, and if not, a second type of DM-RS may be used. The reference signal pattern of the first type of DM-RS may be different 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 may estimate the rate of change of the transmitter's phase noise (e.g., based on the eNB's phase offset measurements using default PNRS settings) and may configure the WTRU for an alternative PNRS pattern, e.g., a lower density pattern (e.g., as shown in FIG. 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 data, the channel estimation accuracy may suffer, for example, especially in high mobility scenarios.

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

[0152] The distributed DM-RS may, for example, be mapped to the data portion of a subframe with a higher or lower density of reference signals depending on the mobility, and in a higher mobility scenario a higher density pattern may be used (e.g., as shown in FIG. 17), while in low to medium mobility a lower density pattern may be used.

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

[0154] For DL ​​and UL transmissions, the configured DM-RS pattern may 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, e.g., regardless of the type of configured distributed DM-RS pattern, to account for different numbers of available resource elements (REs), and / or a rate-matching pattern may be defined to be associated with each distributed DM-RS pattern type. For example, when configured for a dense distributed DM-RS pattern type, the WTRU may select a corresponding rate-matching pattern to apply (e.g., for the signaled TBS). The rate-matching pattern may be kept the same (e.g., regardless of the DM-RS pattern type), and a different set of transport block sizes may be defined and associated with each distributed DM-RS pattern type. Based on the selected DM-RS pattern type, a corresponding TBS table may be used.

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

[0157] The PNRS and the DM-RS may be associated. One or more DM-RS ports may be used for PDSCH or PUSCH transmission. The number of DM-RS ports used for PDSCH or PUSCH transmission may be determined based on the number of layers used for, allocated for, or determined for the PDSCH or PUSCH transmission, where the number of layers may be referred to as a transmission rank. One or more of the following may apply: the number of layers for the PDSCH or PUSCH transmission may be indicated in an associated DCI, the presence and / or PNRS density may be determined based on the number of layers indicated for the PDSCH or PUSCH transmission, 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 the WTRU.

[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 number of layers, an indication of MU-MIMO operation, an indication of a set of DM-RS ports associated with the number of layers, or an indication of a set of DM-RS ports. The number of OFDM symbols used for the DM-RS may be determined based on the indicated number of layers.

[0159] The presence and / or PNRS density 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, and 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 the PNRS ports and the DM-RS ports, where the mapped DM-RS ports and the PNRS ports may be considered to be quasi-collocated with respect to at least one of the QCL parameters (e.g., delay spread, Doppler spread, frequency shift, average received power, spatial Rx parameters, etc.).

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

[0161] The number of PNRS ports (or PNRS density) may be determined based on the number of codewords used, scheduled for, or determined for the WTRU. For example, if the WTRU is scheduled with a single codeword, a single PNRS port may be used, while if the WTRU is scheduled with 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 the WTRU may receive. For example, the WTRU may receive one or more DCIs, where each DCI may be associated with a codeword. The PNRS presence and / or density of each codeword may be determined based on one or more of the scheduling parameters of each codeword. The WTRU may receive two DCIs for PDSCH transmission, where the DCIs may be associated with a codeword and include the scheduling parameters of each codeword. The PNRS presence and / or density 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 of each codeword. The presence and / or density (including zero density) of PNRS for a codeword may be determined based on the QCL status among the DM-RS of one or more codewords. For example, the DM-RS of a scheduled codeword may be QCLed and the PNRS may be transmitted in a subset of the codeword (e.g., only a single codeword includes PNRS), but if the DM-RS of a scheduled codeword is not QCLed, the presence and / or density of PNRS may be determined based on the scheduling parameters of the associated DCI or codeword.

[0162] In an example, one or more PNRS may be transmitted or received, and (e.g., 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 the scheduled PRBs may include 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 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 number of DM-RS ports), the number of scheduled PRBs (or scheduled bandwidth), the number of PNRS ports (or number of subcarriers used for PNRS in a PRB), and / or a PRB index or PRB location within the scheduled PRB (nth PRB).

[0163] The UCI may be transmitted on the PUSCH with or without data. The UCI may include at least one of channel state information (e.g., CQI, PMI, RI, CRI, etc.) and HARQ-ACK information (e.g., ACK or NACK). One or more channel state information (CSI) types may be used. The CSI types may be associated with CSI parameters. The CSI parameters may include one or more of a channel quality indicator (CQI), a wideband CQI, a subband CQI, a CQI for the first codeword and / or a CQI for the second codeword, a precoding matrix indicator (PMI), a wideband PMI, a subband PMI, a PMI for the first component codebook (e.g., i1), a PMI for the second component codebook (e.g., i2), a multi-component codebook structure W1W2 (e.g., W1 may be the first component codebook and W2 may be the second component codebook), a CRI (e.g., a CSI-RS resource indicator), a rank indicator (RI), and / or a precoding type indicator (PTI).

[0164] One or more HARQ-ACK information types may be used. The HARQ-ACK information type may be associated with a number of HARQ-ACK bits and / or code block groups (CBGs). For example, the HARQ-ACK information type may be associated with a single-bit HARQ-ACK. The HARQ-ACK information type may be associated with a two-bit HARQ-ACK. The HARQ-ACK information type may be associated with a code block group (CBG). The 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. The UCI part may include one or more CSI types and / or HARQ-ACK information types. The UCIs may be coded separately and transmitted simultaneously. The first UCI part may include one or more CSI types. The first UCI part may have a constant payload size regardless of the values ​​that may be determined for the one or more CSI types. For example, the CRI, RI, PTI, and CQI for the first codeword may be the first UCI part. The second UCI part may include one or more CSI types. The second UCI part may have a variable payload size that may depend on one or more CSI values ​​in the first UCI part. For example, the PMI and CQI of the second codeword may be the second UCI part, the payload size of which may be determined based on the RI value of the first UCI part. The third UCI part 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 the PUSCH transmission may be determined based on at least one of the number of REs required for UCI transmission or the particular UCI portion being transmitted.

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

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

[0169] [Table 1]

[0170] The PTRS pattern and / or PTRS type for the PUSCH transmission may be determined based on the particular UCI portion being transmitted. For example, if the first and / or second UCI portion is transmitted on the PUSCH, the first PTRS pattern may be used, and if the third UCI portion is transmitted on the PUSCH, the second PTRS pattern may be used. The PTRS pattern may be different if a set of UCI portions is transmitted on the PUSCH. The PTRS pattern may be determined based on whether the UCI includes 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, and if not, the second PTRS pattern may be used for the PUSCH transmission. The PTRS pattern and / or PTRS type for the PUSCH transmission may be determined based on the presence of 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] An example of a PTRS pattern determination based on which UCI portion is transmitted on the PUSCH is shown in Table 2. The PTRS pattern determination may be based on the presence of one or more UCI portions in the PUSCH.

[0172] [Table 2]

[0173] Sounding reference signal (SRS) transmission is disclosed. The sounding reference signal (SRS) transmission may include one or more of a sub-band SRS or SRS transmission and RE muting for SRS.

[0174] An example of Tx / Rx beam sweep based on SRS is shown in Figure 18 and Figure 19. An example of SRS transmission for beam measurement is shown in Figure 20. An example of SRS transmission using subband hopping is shown in Figure 21.

[0175] Sub-band SRS is disclosed. A common design for CSI-RS and SRS may be beneficial since 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. Multi-shot SRS transmission may be used since the number of transmitter and receiver beams to be measured may be multiple. Multi-shot may mean that the SRS (e.g., a set of SRS) may be transmitted in consecutive OFDM symbols and / or over a set of OFDM symbols that may follow a sequence or pattern in time (and / or frequency) that may be configured, determined, and / or known. The SRS transmitted in each of the OFDM symbols may be the same or different. As an example, in FIG. 18, the WTRU is transmitting the same SRS while the eNB is sweeping its receive beams, and in FIG. 19, the WTRU is sweeping its SRS, e.g., the WTRU is sweeping the beam it uses for transmitting the SRS.

[0176] The sequence or pattern may be configured or determined with respect to at least one of the symbols, slots (e.g., time slots), and / or minislots. The sequence or pattern may be a function of a burst time, e.g., a burst time of a beam or synchronization signal, a time window (e.g., a beam time window), or a time block (e.g., a beam time block). The burst time, time block, or time window may be an amount of time (e.g., a continuous amount of time). The burst time, time block, or time window may be an amount of time (e.g., a continuous amount of time) during which a beam direction may be used for transmission or reception. For example, the direction may not change during the 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] In one example, the WTRU may transmit a multi-shot SRS, which may be a set of SRS transmitted in one or more symbols in each of a set of burst times, time windows, or time blocks. The transmission may be according to a configuration that may be provided by an eNB (e.g., gNB) eNB and gNB may be used interchangeably) or other network entity.

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

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

[0180] SRS transmission and RE muting for SRS are disclosed. A resource element (RE) may be or correspond to a time and / or frequency resource or a set of time and / or frequency resources. For example, a RE may be or correspond to a set of symbols (e.g., one or more symbols) and a set of frequencies or subcarriers (e.g., N frequencies or subcarriers). The frequencies or subcarriers may be a subset of frequencies or subcarriers within a transmission band or bandwidth.

[0181] The SRS may be transmitted, for example, by the WTRU in a set of REs that may be distributed across the system bandwidth or across subbands of the system bandwidth. The SRS may be transmitted in one or more symbols that may be adjacent or non-adjacent in time. In one example, an RE may correspond to one symbol and N subcarriers. The SRS may be transmitted in a set of REs in which the transmitting RE may be configured.

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

[0183] a set of S RE sets, e.g., a set of REs that may be used for SRS transmission during a time period (e.g., a subframe or TTI), such as the current or next time period; a number of symbols (e.g., consecutive symbols) over which the SRS (e.g., multi-shot SRS) may be transmitted (e.g., the number of symbols may be configured for one or more sets (e.g., for a set (e.g., individually for each set) or once for all sets or a subset of a set); an interval (e.g., in time or symbols) between symbols for multi-shot transmission; a burst time between SRS transmissions or sets of SRS transmissions; At least one of the following may be configured or indicated (e.g., the WTRU may receive a configuration or indication of at least one of): an interval in time blocks or time windows; a pattern of burst times, time blocks or time windows for SRS transmission that may enable the WTRU to determine the burst times, time blocks, and / or time windows during which it transmits the SRS (e.g., transmits the SRS in one or more symbols); or whether and / or how often it changes (e.g., sweeps) its transmit beam or direction during an SRS transmission (e.g., during a multi-shot SRS transmission).

[0184] A subframe may be used herein as an example of a time unit. Another unit 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 minislot may be replaced with a subframe and still be consistent with this disclosure.

[0185] The RE set may be configured with periodicity.

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

[0187] The WTRU may receive an indication (e.g., a trigger) to transmit an SRS (e.g., dynamically). The indication may be referred to herein as an SRS trigger. For example, the SRS trigger may be provided (e.g., by an eNB) in or with an UL grant and / or received (e.g., by the WTRU). The SRS trigger may be received in DL control information (DCI), e.g., in a DCI format that is or may include an UL grant. The WTRU may transmit the SRS based on receiving the SRS trigger. The WTRU may transmit the SRS in a time period (e.g., a subframe or TTI) in which the WTRU may transmit an UL channel (e.g., a PUSCH) in which the grant was received.

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

[0189] In one example, the WTRU may receive a configuration of a set of S REs. The WTRU may receive an SRS trigger, e.g., in or with a UL grant, and receive a configuration or indication to transmit the SRS using one or more sets of REs, which may be a subset of the set of S REs. The indication may identify the set of REs by an index or other identifier for the set of S REs. The indication may explicitly identify the set of REs.

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

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

[0192] The WTRU may, for example, rate-match around the REs used for SRS in a symbol. 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 REs used for SRS. For example, the WTRU may rate-match a data channel (e.g., PUSCH) transmission or a control channel (e.g., PUCCH) transmission around the REs used for SRS transmission. PUSCH and PUCCH may be used as examples of channels the WTRU may transmit. Other channels may be used consistent with this disclosure.

[0193] The WTRU may rate-match around the REs in a set of REs that the WTRU may use for SRS transmission. In one example, for example, if the WTRU receives a UL grant and an SRS trigger together, the WTRU may transmit a PUSCH and an SRS during the same time period. When transmitting a PUSCH, the WTRU may rate-match around one or more sets of REs that it uses for SRS transmission.

[0194] Rate matching around a set of REs (e.g., rate matching a transmission) may mean not mapping coded bits (e.g., of a transmission) to a set of REs. For example, when mapping coded bits of a PUSCH to REs during a time period, the WTRU may skip REs used for SRS transmission (e.g., that the WTRU or another WTRU may use for SRS transmission) during that time period. The time period may be, for example, a symbol or a subframe.

[0195] The first WTRU may receive a configuration of a set of one or more REs that the second WTRU may use for SRS transmission during a period of time. The configuration may be provided in or with an UL grant received by the first WTRU. The configuration may be provided, for example, in DL control information (DCI) or a DL control channel. The DCI or DL ​​control information may be separate from the DCI or DL ​​control channel for the UL grant of the first WTRU.

[0196] The first WTRU may rate match around REs in a set of REs that the second WTRU may use for SRS transmission. A configuration or indication of the set of REs that may be used by the second WTRU for SRS transmission may be provided to and / or received by the first WTRU, e.g., in, together with, and / or separately from the first WTRU in an UL grant for the first WTRU.

[0197] In one example, a first WTRU may receive a UL grant 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. When transmitting a PUSCH, the WTRU may rate match around the REs that may be used by at least a second WTRU for the SRS.

[0198] The number of bits that may be transmitted per RE may affect, for example, the power that a WTRU may need or 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 may affect the power that a WTRU may need or 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 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 as REs that are unavailable (e.g., during a time period), for example, when determining available REs for transmission (e.g., during a time period) and / or when determining power for transmission (e.g., during a time period), REs that may be used for SRS transmission, REs that may be used for DMRS by the first WTRU, or REs that may be used for UL control information (UCI) transmission, for example, when a UCI transmission may be piggybacked on a PUSCH transmission.

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

[0202] The WTRU may determine the power independent of the available REs if the number of unavailable REs falls below a threshold, which may be configurable, for example.

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

[0204] The WTRU may be configured with semi-persistent scheduling (SPS), e.g., for UL transmissions. SPS may provide the WTRU with a grant or allocation of resources in the UL that it may use over multiple periods of time (e.g., multiple slots or subframes) without receiving additional grants (e.g., for new data). In some of those time periods, at least some of the resources used or allocated to the SPS transmissions may be used by the WTRU (e.g., another WTRU) for SRS.

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

[0206] A first WTRU may receive an indication indicating when another (e.g., a second) WTRU may transmit an SRS according to an SRS configuration, e.g., an SRS configuration described herein. The SRS configuration may provide, e.g., a set of symbols and / or REs. The SRS configuration may provide, e.g., a time and / or frequency pattern.

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

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

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

[0210] Activate / deactivate may be used to refer to activation and / or deactivation. Enable and activate may be used interchangeably. Disable and deactivate may be used interchangeably.

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

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

[0213] A semi-permanent SRS may be provided.

[0214] The WTRU may transmit an SRS, e.g., a multi-shot SRS, and / or may be configured to do so. The WTRU may receive a configuration for SRS transmission. The WTRU may receive activation and / or deactivation for SRS transmission.

[0215] The WTRU may, for example, transmit the SRS according to at least the received configuration. The WTRU may transmit, e.g., start transmitting, the SRS in response to receiving an activation of the SRS. The WTRU may not transmit, e.g., stop transmitting, the SRS in response to receiving a deactivation of the SRS.

[0216] In one example, the SRS activation and / or SRS deactivation may be provided in and / or received within a MAC control element (eg, a MAC-CE).

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

[0218] The WTRU may be configured with a time window or other parameters that may limit the number of SRS transmissions and / or times during which the WTRU may transmit an SRS, for example, to ensure deactivation of the SRS in the event that a deactivation request may be lost.

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

[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 an SRS activation (e.g., the last or most recent SRS activation) is transmitted (e.g., by the gNB) and / or received (e.g., by the WTRU).

[0221] For example, a WTRU may receive an activation of an SRS during time unit (e.g., subframe, slot, or minislot) n. The WTRU may start transmitting the 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 starting time (e.g., time 0) for counting time from receipt of the activation.

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

[0223] The duration parameter, which may be the maximum time window, may be configured by a broadcast signal or WTRU-specific signaling. For example, the parameter may be provided by RRC signaling. In an example, the parameter may be included in a MAC-CE, such as a MAC-CE providing activation and / or deactivation.

[0224] In one 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 may correspond to and / or result in, for example, the WTRU only using deactivation, e.g., a deactivation request, to stop SRS transmission after the SRS transmission has been activated.

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

[0226] In one example, a WTRU may be activated (e.g., to transmit an SRS) with a duration parameter such as infinity or always, which may indicate to the WTRU to transmit the SRS until receiving a deactivation (e.g., according to a configuration that may have been previously received). The WTRU may transmit the SRS in response to the activation. The WTRU may be activated or deactivated with a duration parameter such as 0, which may indicate to stop transmitting the SRS. The WTRU may stop transmitting the SRS in response to the activation or deactivation.

[0227] Demodulation reference signal (DM-RS) transmission may be provided. For example, DM-RS sequences 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 across adjacent OFDM symbols using a time-domain orthogonal cover code (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 number of subcarriers used in an OFDM symbol or DFT-s-OFDM symbol, an orthogonal cover code (OCC) in the time or frequency domain, the number of cyclic shifts of the DM-RS sequence, and / or the number of symbols (e.g., OFDM symbols or DFT-s-OFDM symbols) used for the DM-RS.

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

[0230] An orthogonal cover code (OCC) in the time domain or the 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., a 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., a FD-OCC may use

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

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

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

[0233] The DM-RS configurations of the one or more DM-RS configurations may be determined based on 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) and 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), the first DM-RS configuration may be used and if the associated DCI is received in the second NR-PDCCH search space (or second NR-PDCCH CORESET), the second DM-RS configuration may be used). The CORESET may be referred to as an NR-PDCCH resource set.), 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 operation mode (a first DM-RS configuration may be used when the WTRU is configured in a first MIMO operation mode (e.g., a SU-MIMO mode), a second DM-RS configuration may be used when the WTRU is configured in a second MIMO operation mode (e.g., a 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 repetition. 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 FIG. 23, the 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. The K sequences may be orthogonal. The same DM-RS symbol may be repeated on adjacent OFDM symbols. This may be designated configuration 1 for ease of explanation.

[0236] For example, a DM-RS sequence for an antenna port may be mapped to every k-1 subcarrier. As an example, in FIG. 23, the DM-RS sequence is mapped to every other subcarrier in the 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 designated configuration 2 for ease 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 an orthogonal cover code. For example, on subcarrier k (assuming two OFDM symbols), r1

[0011] and r2 [1 -1] may be transmitted on two OFDM symbols, e.g., 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 varies significantly from one OFDM symbol to another, loss of orthogonality may occur and r1 and r2 may not be completely separated at the receiver. This may be due to, for example, phase noise, as the phase noise may vary from one OFDM symbol to another. The effect of phase noise may be greater at higher frequencies. Similarly, high mobility may result in loss of orthogonality.

[0238] The configuration for DM-RS transmission may be implicitly determined by one or more of the following. The configuration may be generalized such that one configuration (Configuration 1) may be a DM-RS configuration that does not use time-domain cover spreading, while another configuration (Configuration 2) may 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 may be used; when fc < Fc, Configuration 2 may be used.

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

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

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

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

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

[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 time-domain cover codes. DM-RS ports can be multiplexed across adjacent subcarriers using frequency-domain orthogonal cover codes. On top of this, time-domain cover codes can be used to spread 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 time-domain cover codes, while another configuration (Configuration 2) can be a DM-RS configuration using time-domain cover codes 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. When the subcarrier spacing (Δf): if Δf≧F, Configuration 1 can be used; if Δf<F, Configuration 2 can be used. When the 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] FIG. 26 shows an example of PNRS frequency densities for QPSK, 16QAM, and 64QAM modulation.

[0248] An example of determining frequency density for PNRS transmission is shown in Figure 27. The subset of PRBs for PNRS transmission may be based on WTRU ID (e.g., to randomize multi-user interference). PNRS frequency density may be based on MCS level (e.g., 16QAM may have density 1 and 64QAM may have density 2).

[0249] Although the features and elements are described above in certain combinations, one skilled in the art will appreciate that each feature or element may be used alone or in any combination with other features and elements. Additionally, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, a WTRU, a terminal, a base station, an RNC, or any host computer.

[0250] It should be understood that although the features and elements herein may be considered in terms of LTE, LTE-A, New Radio (NR), or 5G specific protocols, the solutions described herein are not limited to these scenarios and may be applicable to other wireless systems.

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: Memory, receiving an indication that the WTRU will transmit one or more phase noise reference signals; receiving scheduling information including an indication of a set of uplink resources and an indication of a modulation and coding scheme, the set of uplink resources corresponding to a plurality of resource blocks (RBs); determining a phase noise reference signal density for the transmission of the one or more phase noise reference signal transmissions, the phase noise reference signal density being determined based at least on the indication of the modulation and coding scheme; determining a phase noise reference signal pattern for the transmission of the one or more phase noise reference signal transmissions, the phase noise reference signal pattern being determined based on a number of groups of phase noise reference signals to be transmitted and based on a number of phase noise reference signal samples per group; determining a first subset of the set of uplink resources and a second subset of the set of uplink resources, the first subset of the set of uplink resources being used for transmitting the one or more phase noise reference signals and the second subset of the set of uplink resources being used for transmitting data associated with an uplink transmission, the first subset of the set of uplink resources being included in a subset of the plurality of RBs, the subset of the plurality of RBs including the first subset of the set of uplink resources being determined based on at least a 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 processor for executing instructions from said memory such that A WTRU comprising:

2. The WTRU of claim 1 , wherein the number of groups of phase noise reference signals corresponds to a number of phase noise reference signal chunks.

3. 2. The WTRU of claim 1, wherein the scheduling information is received in an uplink grant message, the uplink grant message including an indication used by the WTRU to determine the subset of the plurality of RBs that includes the first subset of the set of uplink resources.

4. 2. The WTRU of claim 1, wherein the phase noise reference signal density is a time density.

5. 2. The WTRU of claim 1, wherein if the level of the modulation and coding scheme is higher than a predefined threshold, the phase noise reference signal density is determined to be a predefined density for a Physical Uplink Shared Channel (PUSCH) transmission.

6. 2. The WTRU of claim 1, wherein the uplink transmission is a Physical Uplink Shared Channel (PUSCH) transmission.

7. 7. The WTRU of claim 6, wherein the indicated modulation and coding scheme is associated with the PUSCH transmission.

8. 1. A method performed by a wireless transmit / receive unit (WTRU), comprising: receiving an indication that the WTRU is transmitting one or more phase noise reference signals; receiving scheduling information including an indication of a set of uplink resources and an indication of a modulation and coding scheme, the set of uplink resources corresponding to a plurality of resource blocks (RBs); determining a phase noise reference signal density for the transmission of the one or more phase noise reference signal transmissions, the phase noise reference signal density being determined based at least on the indication of the modulation and coding scheme; determining a phase noise reference signal pattern for the transmission of the one or more phase noise reference signal transmissions, the phase noise reference signal pattern being determined based on a number of groups of phase noise reference signals to be transmitted and based on a number of phase noise reference signal samples per group; determining a first subset of the set of uplink resources and a second subset of the set of uplink resources, wherein the first subset of the set of uplink resources is used for transmission of the one or more phase noise reference signals and the second subset of the set of uplink resources is used for transmission of data associated with an uplink transmission, the first subset of the set of uplink resources being 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 a 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 comprising:

9. 9. The method of claim 8, wherein the number of groups of phase noise reference signals corresponds to a number of phase noise reference signal chunks.

10. 9. The method of claim 8, wherein the scheduling information is received in an uplink grant message, the uplink grant message including an indication used by the WTRU to determine the subset of the plurality of RBs that comprises the first subset of the set of uplink resources.

11. 9. The method of claim 8, wherein the phase noise reference signal density is a time density.

12. 9. The method of claim 8, wherein if the level of the modulation and coding scheme is higher than a predefined threshold, the phase noise reference signal density is determined to be a predefined density for a Physical Uplink Shared Channel (PUSCH) transmission.

13. 10. The method of claim 8, wherein the uplink transmission is a Physical Uplink Shared Channel (PUSCH) transmission.

14. 14. The method of claim 13, wherein the indicated modulation and coding scheme is associated with the PUSCH transmission.

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