WO2020069207A1 - Conception de signal de référence pour v2x - Google Patents

Conception de signal de référence pour v2x Download PDF

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Publication number
WO2020069207A1
WO2020069207A1 PCT/US2019/053284 US2019053284W WO2020069207A1 WO 2020069207 A1 WO2020069207 A1 WO 2020069207A1 US 2019053284 W US2019053284 W US 2019053284W WO 2020069207 A1 WO2020069207 A1 WO 2020069207A1
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WO
WIPO (PCT)
Prior art keywords
wtru
dmrs
configuration
transmission
wtrus
Prior art date
Application number
PCT/US2019/053284
Other languages
English (en)
Inventor
Erdem Bala
Fengjun Xi
Kyle Jung-Lin Pan
Chunxuan Ye
Original Assignee
Idac Holdings, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Idac Holdings, Inc. filed Critical Idac Holdings, Inc.
Publication of WO2020069207A1 publication Critical patent/WO2020069207A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/14—Direct-mode setup

Definitions

  • a wireless transmit receive unit may receive a configuration of one or more resource pools. Each resource pool may be associated with a set demodulation reference signals (DMRSs) configurations. Each DMRS configuration may be associated with a DMRS pattern.
  • the WTRU may receive information associated with a traffic type from a higher layer, and based on that information determine a DMRS pattern from the set of DMRS configurations to use for transmission.
  • the WTRU may transmit an indication of this determined DMRS pattern in a control channel (e.g., sidelink control information).
  • the WTRU may then proceed to use this DMRS pattern for data transmission.
  • the WTRU may receive a response to the data transmission, where a response is transmitted using the DMRS pattern.
  • the WTRU may update the DMRS configuration if necessary.
  • FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented
  • FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;
  • WTRU wireless transmit/receive unit
  • FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;
  • RAN radio access network
  • CN core network
  • FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment
  • FIG. 2 is a collection of resource diagrams illustrating examples of sparse reference signal (RS);
  • FIG. 3 is a resource diagram illustrating an example of third and second zero-power resource elements
  • FIG. 4 is a collection of power level diagrams illustrating examples of lower power resource elements
  • FIG. 5 is a flow chart illustrating an example process of transmission mode selection
  • FIG. 6 is a resource diagram illustrating an example of the structure of the discovery signal using beamforming
  • FIG. 7 is a resource diagram illustrating an example of a physical shared feedback channel (PSFCH) transmission
  • FIG. 8 a transmission diagram illustrating an example of robust ACK/NACK transmission
  • FIG. 9 is a resource diagram illustrating an example pattern of robust data transmission where every other RE is set to zero power
  • FIG. 10 is a resource diagram illustrating an example of reference signal multiplexing with two RSs associated with two ports
  • FIG. 1 1 is a signal processing diagram illustrating an example of pre-DFT RS and data multiplexing in a uniform pattern
  • FIG. 12 is a diagram illustrating an example of pre-DFT RS and data multiplexing
  • FIG. 13 is a flow chart illustrating an example process of reference signal configuration update
  • FIG. 14 is a resource diagram illustrating an example of resource units
  • FIG. 15 is a diagram illustrating one or more candidate resource units (RUs) organized in resource pools
  • FIG. 16 is a flow chart illustrating an example process for avoiding unnecessary demodulation reference signal (DMRS) overhead
  • FIG. 17 is a flow chart illustrating an example process of reference signal configuration adaption for platooning
  • FIG. 18 is a resource diagram illustrating an example of zero-power adjacent resource elements based DRMS and phase-tracking reference signal (PTRS) pattern;
  • PTRS phase-tracking reference signal
  • FIG. 19 is a collection of transmission diagrams illustrating an example of reservation signals.
  • FIG. 20 is a transmission diagram illustrating an example of a reservation signal DMRS.
  • FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented.
  • the communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users.
  • the communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth.
  • the communications systems 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 discrete Fourier transform Spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal FDMA
  • SC-FDMA single-carrier FDMA
  • ZT-UW-DFT-S-OFDM zero-tail unique-word discrete Fourier transform Spread OFDM
  • UW-OFDM unique word OFDM
  • FBMC filter bank multicarrier
  • the communications system 100 may include wireless/wired transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, a public switched telephone network (PSTN) 108, the Internet 1 10, and other networks 1 12, though 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.
  • the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and/or receive wireless signals, or a wired signal, and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like.
  • UE user equipment
  • PDA personal digital assistant
  • HMD head-mounted display
  • any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.
  • a WTRU may be associated with, permanently attached, removably attached, or integrated with a vehicle, such as an air, land, or water vehicle. Reference to a vehicle, as disclosed herein, may be substituted for a WTRU unless otherwise explained. Further, reference herein to a transmitter or a receiver may refer to a receiving WTRU or a transmitting/sending WTRU.
  • the communications systems 100 may also include a base station 114a and/or a base station 1 14b.
  • Each of the base stations 1 14a, 1 14b 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, the Internet 1 10, and/or the other networks 112.
  • the base stations 1 14a, 1 14b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 1 14a, 1 14b are each depicted as a single element, it will be appreciated that the base stations 1 14a, 114b may include any number of interconnected base stations and/or network elements.
  • the base station 114a may be part of the RAN 104, 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, and the like.
  • the base station 1 14a and/or the base station 1 14b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum.
  • a cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors.
  • the cell associated with the base station 1 14a may be divided into three sectors.
  • the base station 1 14a may include three transceivers, i.e., one for each sector of the cell.
  • the base station 1 14a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell.
  • MIMO multiple-input multiple output
  • beamforming may be used to transmit and/or receive signals in desired spatial directions.
  • the base stations 1 14a, 1 14b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 1 16, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.).
  • the air interface 1 16 may be established using any suitable radio access technology (RAT).
  • RAT radio access technology
  • the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like.
  • the base station 1 14a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA).
  • WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (FISPA+).
  • HSPA may include High-Speed Downlink (DL) Packet Access (FISDPA) and/or High-Speed Uplink (UL) Packet Access (HSUPA).
  • the base station 1 14a 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 1 16 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).
  • E-UTRA Evolved UMTS Terrestrial Radio Access
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • LTE-A Pro LTE-Advanced Pro
  • the base station 1 14a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 1 16 using NR.
  • a radio technology such as NR Radio Access
  • the base station 1 14a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies.
  • the base station 1 14a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles.
  • DC dual connectivity
  • the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., an eNB and a gNB).
  • the base station 1 14a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.
  • IEEE 802.11 i.e., Wireless Fidelity (WiFi)
  • IEEE 802.16 i.e., Worldwide Interoperability for Microwave Access (WiMAX)
  • CDMA2000, CDMA2000 1X, CDMA2000 EV-DO Code Division Multiple Access 2000
  • IS-95 Interim Standard 95
  • IS-856 Interim Standard 856
  • GSM Global System for
  • the base station 1 14b in FIG. 1 A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like.
  • the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.1 1 to establish a wireless local area network (WLAN).
  • WLAN wireless local area network
  • the base station 1 14b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN).
  • the base station 1 14b 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.
  • the base station 1 14b may have a direct connection to the Internet 1 10.
  • the base station 1 14b may not be required to access the Internet 1 10 via the CN 106.
  • the RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d.
  • the data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like.
  • QoS quality of service
  • the CN 106 may provide call control, billing services, mobile location- based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high- level security functions, such as user authentication.
  • the RAN 104 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT.
  • the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.
  • the CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 1 12.
  • the PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS).
  • POTS plain old telephone service
  • the Internet 1 10 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite.
  • the networks 1 12 may include wired and/or wireless communications networks owned and/or operated by other service providers.
  • the networks 1 12 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.
  • 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).
  • the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 1 14b, which may employ an IEEE 802 radio technology.
  • FIG. 1 B is a system diagram illustrating an example WTRU 102.
  • the WTRU 102 may include 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, among others.
  • GPS global positioning system
  • the processor 1 18 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of integrated circuit (IC), a state machine, and the like.
  • the processor 1 18 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 1 18 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 1 18 and the transceiver 120 as separate components, it will be appreciated that the processor 1 18 and the transceiver 120 may be integrated together in an electronic package or chip.
  • the transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 1 14a) over the air interface 1 16.
  • a base station e.g., the base station 1 14a
  • the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals.
  • the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example.
  • 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.
  • the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 1 16.
  • the transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122.
  • the WTRU 102 may have multi-mode capabilities.
  • the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.1 1 , for example.
  • the processor 118 of the WTRU 102 may be coupled to, and may 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 organic light-emitting diode (OLED) display unit).
  • the processor 1 18 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128.
  • the processor 1 18 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132.
  • the non-removable memory 130 may include random-access memory (RAM), readonly memory (ROM), a hard disk, or any other type of memory storage device.
  • the removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like.
  • SIM subscriber identity module
  • SD secure digital
  • the processor 1 18 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).
  • the processor 1 18 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102.
  • the power source 134 may be any suitable device for powering the WTRU 102.
  • 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, and the like.
  • the processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102.
  • location information e.g., longitude and latitude
  • the WTRU 102 may receive location information over the air interface 1 16 from a base station (e.g., base stations 1 14a, 1 14b) and/or determine its location based on the timing of the signals being 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.
  • 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.
  • the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (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 the like.
  • FM frequency modulated
  • the peripherals 138 may include one or more sensors.
  • the sensors 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, a humidity sensor and the like.
  • the WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and/or simultaneous.
  • the full duplex radio may include an interference management unit to reduce and or substantially eliminate selfinterference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 1 18).
  • the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the DL (e.g., for reception)).
  • a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the DL (e.g., for reception)).
  • FIG. 1 C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment.
  • the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116.
  • the RAN 104 may also be in communication with the CN 106.
  • the RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment.
  • the eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 1 16.
  • the eNode-Bs 160a, 160b, 160c may implement MIMO technology.
  • the eNode-B 160a for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.
  • Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.
  • the CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are depicted 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.
  • MME mobility management entity
  • SGW serving gateway
  • PGW packet data network gateway
  • PGW packet data network gateway
  • the MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node.
  • the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like.
  • the MME 162 may 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.
  • the SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface.
  • the SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c.
  • the SGW 164 may perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.
  • the SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • packet-switched networks such as the Internet 1 10
  • the CN 106 may facilitate communications with other networks.
  • 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 landline communications devices.
  • the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108.
  • IMS IP multimedia subsystem
  • the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.
  • the WTRU is described in FIGS. 1 A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.
  • the other network 1 12 may be a WLAN.
  • 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 an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS.
  • Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs.
  • Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations.
  • Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA.
  • the traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic.
  • the peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS).
  • the DLS may use an 802.1 1 e DLS or an 802.11 z tunneled DLS (TDLS).
  • a WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other.
  • the IBSS mode of communication may sometimes be referred to herein as an“ad-hoc” mode of communication.
  • the AP may transmit a beacon on a fixed channel, such as a primary channel.
  • the primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width.
  • the primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP.
  • Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in 802.11 systems.
  • the STAs e.g., every STA, including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off.
  • One STA (e.g., only one station) may transmit at any given time in a given BSS.
  • High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.
  • V HT STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels.
  • the 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels.
  • a 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration.
  • the data, after channel encoding may be passed through a segment parser that may divide the data into two streams.
  • Inverse Fast Fourier Transform (IFFT) processing, and time domain processing may be done on each stream separately.
  • IFFT Inverse Fast Fourier Transform
  • the streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA.
  • the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).
  • MAC Medium Access Control
  • Sub 1 GHz modes of operation are supported by 802.1 1 af and 802.1 1 ah.
  • the channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.1 1 ah relative to those used in 802.1 1 h, and 802.1 1 ac.
  • 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum
  • 802.1 1 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum.
  • 802.1 1 ah may support Meter Type Control/Machine-Type Communications (MTC), such as MTC devices in a macro coverage area.
  • MTC Meter Type Control/Machine-Type Communications
  • MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths.
  • the MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).
  • WLAN systems which may support multiple channels, and channel bandwidths, such as 802.1 1 h, 802.1 1 ac, 802.1 1 af, and 802.1 1 ah, include a channel which may be designated as the 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 a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode.
  • the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.
  • Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.
  • STAs e.g., MTC type devices
  • NAV Network Allocation Vector
  • the available frequency bands which may be used by 802.1 1 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.
  • FIG. 1D is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment.
  • the RAN 104 may employ an NR 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.
  • the RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 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.
  • the gNBs 180a, 180b, 180c may implement MIMO technology.
  • gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c.
  • the gNB 180a may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.
  • the gNBs 180a, 180b, 180c may implement carrier aggregation technology.
  • the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum.
  • the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology.
  • WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).
  • CoMP Coordinated Multi-Point
  • the WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum.
  • the WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and/or lasting varying lengths of absolute time).
  • TTIs subframe or transmission time intervals
  • 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.
  • WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c).
  • WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point.
  • WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band.
  • WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c.
  • WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously.
  • eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.
  • 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 of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.
  • UPF User Plane Function
  • AMF Access and Mobility Management Function
  • the CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are depicted 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.
  • SMF Session Management Function
  • the AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node.
  • the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like.
  • PDU protocol data unit
  • Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c.
  • different network slices may be established for different use cases such as services relying on ultrareliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like.
  • URLLC ultrareliable low latency
  • eMBB enhanced massive mobile broadband
  • the AMF 182a, 182b may provide a control plane function for switching between the RAN 104 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.
  • the SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N1 1 interface.
  • the SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface.
  • the SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b.
  • the SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like.
  • a PDU session type may be IP- based, non-IP based, Ethernet-based, and the like.
  • the UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • the UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.
  • the CN 106 may facilitate communications with other networks.
  • the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108.
  • IMS IP multimedia subsystem
  • the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 1 12, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.
  • the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.
  • one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 1 14a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) 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.
  • the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.
  • the emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment.
  • the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network.
  • the one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network.
  • the emulation device may be directly coupled to another device for purposes of testing and/or performing testing using over-the-air wireless communications.
  • the one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network.
  • the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components.
  • the one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.
  • RF circuitry e.g., which may include one or more antennas
  • LTE has supported WTRU to WTRU communication for some uses cases, such as public safety and/or vehicle to everything (V2X)
  • the LTE-based approach may not be compatible for some use cases that use NR.
  • NR may need to support WTRU to WTRU communication in an approach different than LTE.
  • WTRU to WTRU communication i.e., PC5 interface
  • D2D or vehicle to everything (V2X) may be based on NR frame structure and channels.
  • NR V2X use cases such as vehicles platooning, extended sensors, advanced driving, and remote driving may have additional requirements.
  • each of these use cases may be represent a group of use cases and may be representative of latency, reliability and data rate requirements associated with that group, as seen in Table 1.
  • use case(s) i.e., sub-use case
  • use case(s) i.e., sub-use case
  • a“Higher degree of automation” in a sensor information sharing scenario of the extended sensors group between WTRUs supporting V2X applications may have a latency requirement of 3 ms, reliability requirement of 99.999%, and a data rate requirement of 25 Mbps.
  • D2D and V2X may support LTE sidelink.
  • the following physical channels may be used for sidelink transmissions: sidelink primary sync signal (SPSS) and sidelink secondary sync signal (SSSS); physical sidelink broadcasting channel (PSBCH); physical sidelink control channel (PSCCFI); physical sidelink shared channel (PSSCH); and/or physical sidelink discovery channel (PSDCH).
  • SPSS sidelink primary sync signal
  • SSSS sidelink secondary sync signal
  • PSBCH physical sidelink broadcasting channel
  • PSCCFI physical sidelink control channel
  • PSSCH physical sidelink shared channel
  • PSDCH physical sidelink discovery channel
  • Mode 1 and Mode 2 may be designed for D2D communication that has requirements of being power-efficient, high reliability, delay-tolerant, and low mobility.
  • Mode 1 may be based on eNB scheduling for sidelink transmission, where the resource for a sidelink transmission may be scheduled by an eNB via a DCI. Further, Mode 1 may be used when WTRUs for sidelink transmission are located under eNB coverage so that WTRUs may be able to receive the control signal from the eNB.
  • Mode 2 may be based on WTRU autonomous resource selection within a resource pool. Further, Mode 2 may be used when WTRUs for sidelink transmission are out of the eNB coverage and also for in the eNB coverage cases.
  • Mode 3 and 4 may be for V2X communication and support high mobility as well as low latency from the Mode 1 and Mode 2.
  • a WTRU using sidelink may receive a resource grant for sidelink transmission and the resource grant may be monitored in a search space configured for a Uu interface.
  • a structure and design different than that which is used in LTE may be adopted for the physical downlink control channel (PDCCH), as well as the physical downlink shared channel (PDSCH). Also, slot-based and non-slot-based transmissions and different rates of monitoring for PDCCH may be defined.
  • PDCCH physical downlink control channel
  • PDSCH physical downlink shared channel
  • a Resource Element Group may be the smallest building block for transmission in a PDCCH.
  • Each REG may comprise of 12 resource elements (REs) on one OFDM symbol in time and one resource block (RB) in frequency.
  • REs resource elements
  • RB resource block
  • 9 REs may be used for control information and 3 REs may be used for a demodulation reference signal demodulation reference signals (DMRS) .
  • DMRS demodulation reference signal demodulation reference signals
  • Multiple REGs e.g., 2, 3, or 6
  • adjacent in time or frequency may form a REG bundle that may be used with the same precoder and their DMRSs may be used together for channel estimation.
  • Each PDCCFI transmission may comprise of one or multiple CCEs (i.e., 1 , 2, 4, 8, or 16 CCEs) and the number of CCEs for a PDCCFI transmission may be its aggregation level (AL).
  • CCE Control Channel Element
  • a Control Resource Set may be configured by its frequency assignment (i.e., as chunks of 6 RBs), the length in time (i.e., 1 -3 OFDM symbols), the type of REG bundle, and the type of mapping from REG bundles to CCEs (i.e., whether it is interleaving or non-interleaving).
  • the frequency assignment i.e., as chunks of 6 RBs
  • the length in time i.e., 1 -3 OFDM symbols
  • the type of REG bundle i.e., whether it is interleaving or non-interleaving
  • mapping from REG bundles to CCEs i.e., whether it is interleaving or non-interleaving.
  • BWP bandwidth part
  • Each WTRU may be assigned with a set of PDCCFI candidates to be monitored during the blind detection of PDCCFI transmission, which is called a search space or a set of search spaces (i.e., for multiple aggregation levels).
  • Each set of search spaces may be configured by its associated CORESET, the number of candidates with each aggregation level, and the monitoring occasions.
  • the monitoring occasions may be determined by monitoring periodicity (e.g., in terms of slots), monitoring offset, and/or monitoring pattern (e.g., as 14 bits corresponding to all possible patterns of symbols inside a slot).
  • DMRSs may be generated by QPSK modulation of a PN sequence.
  • the reference-signal sequence r ⁇ > may be generated according to:
  • each coefficient of the sequence mapped to one subcarrier in one OFDM symbol may be referred to as a pilot symbol.
  • NR may support two DMRS configurations for OFDM waveform to multiplex multiple antenna ports.
  • each layer of each transmitting WTRU may be considered as one antenna port, so the same multiplexing concept may be used.
  • the DMRS corresponding to one antenna port may be transmitted in every other subcarrier.
  • the DMRS corresponding to another antenna port may be transmitted on the same subcarriers but the two DMRS sharing the subcarriers may be generated by applying different cyclic shifts to one same mother sequence. If there is an additional OFDM symbol, then the time domain spreading may be used to increase the number of antenna ports to 4.
  • up to 4 antenna ports may be multiplexed on two adjacent subcarriers and two OFDM symbols using time and frequency domain spreading.
  • cyclic shifts of sequences may not be used.
  • DMRS DM-RNTI phase noise tracking reference signals
  • Doppler shift may occur due to high-velocity results in inter-carrier interference (ICI) in OFDM and OFDM-like modulation schemes such as DFT-s- OFDM.
  • ICI may impact channel estimation accuracy, and/or phase tracking accuracy, resulting in degraded performance.
  • Very high-velocity situations such as up to 250km/h absolute velocity or up to 500km/h relative velocity may be expected to be supported in NR V2X due to vehicle (e.g., air vehicles) related use cases.
  • ICI may impact the performance using sidelink channels such as a control channel and a shared data channel. Therefore, there is a need to address the issues that may arise as a result of the ICI with methods, systems, and devices that implement a robust reference signal design.
  • ICI intercarrier interference
  • a reference signal may be mapped to the allocated to interleaved subcarriers.
  • Interleaving in frequency means two consecutive pilot symbols are separated with at least one resource element (RE), where a RE may also be referred to as subcarrier, which may be a zero power RE. Reference signals may be mapped to non-adjacent REs.
  • RE resource element
  • FIG. 2 is a collection of diagrams illustrating examples of sparse reference signal resource mapping.
  • the number of zero power REs (i.e., blank boxes) between two consecutive subcarriers loaded with reference signals (i.e., RS 204) is one as shown in example 200, and is three (i.e., RS 224) as shown in example 220.
  • time is shown in OFDM symbols on the horizontal axis (e.g., 201 or 221 ) and frequency is shown in REs on the vertical axis (e.g., 202 or 222).
  • An RS is shown with a dark shaded block (e.g., 204 or 224) and data is shown in a lighter shaded block (e.g., 203 or 223).
  • these examples 200 and 220 show only one OFDM symbol with reference signals (RSs), at 213 and 233 respectively, for the length of time from 21 1 to 212, or 231 to 232 (i.e., per slot ) for illustration purposes, but RS may be mapped to resources on several OFDM symbols within a slot to better track the time-varying channel generally.
  • the first OFDM symbol may be reserved for Automatic Gain Control (AGO) 211 or 231 , and the last OFDM symbol may be used as Guard Period (GP) 212 or 232.
  • AGO Automatic Gain Control
  • GP Guard Period
  • pilot symbols and other types of symbols may be multiplexed over the REs of the same OFDM symbol.
  • phase noise tracking reference signal PTRS
  • additional data demodulation reference signal may also be transmitted on the shared data channel, or on the control channel.
  • one or more REs adjacent to the RE loaded with the reference signal may be left empty (i.e., it may be zero power).
  • FIG. 3 is a diagram illustrating an example of third and second zero-power REs. Time is shown in OFDM symbols on the horizontal axis 301 , and frequency is shown in REs on the vertical axis 302. The first OFDM symbol may be reserved for AGO 31 1 , and the last OFDM symbol may be used as GP 312. DMRS 304, Data 303, and PTRS 305 may be shown using blocks with different patterns. In this example, the 2 nd and 3 rd OFDM symbols 313 carry DMRS, and also PTRSs are transmitted on two REs within the slot at 314. Also, the REs adjacent in frequency to the pilot symbols (e.g., DMRS 304) are zero power (i.e., blank boxes).
  • data may be encoded and rate matched assuming all of the REs in these OFDM symbols are available, except those REs that are already allocated to the RSs and other signals not allocated for data transmission. After encoding and rate matching, the data symbols corresponding to the REs that are desired to be zero power are punctured.
  • data may be encoded and rate matched assuming that the REs that are desired to be zero power are not available to begin with.
  • the REs in the vicinity of the RE carrying RS may not be zero power but the symbols loaded on these REs may have less power than the symbols loaded on the other REs not in the vicinity of the RS subcarrier.
  • a group of REs in the vicinity of the RS subcarrier may be identified. This group may contain at least one subcarrier from the group ⁇ k - M, k - M + 1, ... k - 1, k + 1, ... k + N ⁇ where k is the index of the subcarrier carrying the reference signal (RS subcarrier) and M, N are parameters to define the vicinity of the RS subcarrier.
  • FIG. 4 is a collection of power level diagrams illustrating examples of lower power REs.
  • 410a and 410b with power levels shown vertically (e.g., 402a and 402b) above the subcarriers shown horizontally (e.g., 401 a and 401 b).
  • RS 404 and data 403 may be represented by patterned blocks as shown.
  • the subcarriers (i.e., each block) in the group may be loaded with less power.
  • all these REs may have equal power but less than the power of the RS.
  • power may be a function of the RE index, where the REs closest to the RS may have the least power and the power increases as the distance to the RS increases.
  • the power of the RS may be boosted and the additional power may be taken from the REs with less power.
  • the power of the subcarriers in the vicinity of the RS subcarriers may be determined by the receiver using at least one or more transmission parameters.
  • Traffic type or application type may be a kind of transmission parameter.
  • the transmitter may choose zero-power for certain REs, transmit those REs with less power than maximum power, or transmit those REs with normal power.
  • those REs in the vicinity of the RS subcarriers may be set to zero power.
  • the traffic/application type and RE power association may have to be configured.
  • the variation in speed among vehicles in the same platoon is very small or zero.
  • the intervehicle distance is fixed to a small value, and hence, the relative speed between any two vehicles in the same platoon is 0.
  • data may be transmitted with normal power on the subcarriers in the vicinity to the RS subcarrier.
  • CORESET may be a kind of transmission parameter.
  • the CORESET used for control data transmission may indicate the power of those REs.
  • CORESET aggregation level may be a kind of transmission parameter.
  • the aggregation level of the CORESET may indicate the power of those REs.
  • an aggregation level above a threshold may indicate robust transmission which may be interpreted as those REs on the associated shared data channel having zero power. The same rule may also apply to those REs on the control channel.
  • a resource unit may be a kind of transmission parameter.
  • the RU used for data transmission may indicate the power of those REs.
  • Bandwidth part may be a kind of transmission parameter.
  • the active BWP used for data transmission may indicate the power of those REs (i.e., there may be an association with a BWP and the power of those REs).
  • one BWP may be associated with robust transmission, while another one may be associated with regular transmission.
  • Control information contents may be a kind of transmission parameter.
  • the power of those REs may be signaled dynamically in the control information. For example, if one bit is used for this indication, control information may indicate“zero power” or“non-zero power”.
  • PHY layer measurements may be a kind of transmission parameter.
  • the transmitter and/or receiver may perform certain measurements, and the power of those REs may depend on the outcome of the measurements.
  • a node may measure relative Doppler by using the reference signals on the discovery channel, where a node may be a WTRU or other infrastructure point on a network as disclosed herein. Since every node may need to transmit on the discovery channel, such measurements may be performed by all nodes receiving on the discovery channel. From these measurements, nodes may have an estimate of the relative Doppler between them.
  • an appropriate transmission mode may be selected (e.g., robust or regular configuration) and informed.
  • FIG. 5 is a flow chart illustrating an example process of transmission mode selection.
  • a first WTRU may receive a discovery channel of a second WTRU.
  • the first WTRU may measure the quality of the link (i.e., between the first WTRU and second WTRU).
  • the first WTRU may use a known signal with the discovery channel (e.g., a reference signal).
  • the first WTRU may determine a reference signal configuration (i.e., transmission mode) to be used for the PSSCH and/or PSCCH transmission from the first WTRU to the second WTRU.
  • a reference signal configuration i.e., transmission mode
  • connection may be set-up, where the determined RS configuration may be indicated by the first WTRU to the second WTRU in the PSCCH. Additionally/alternatively, measurements based on CSI-RS or other types of reference signals may be used while transmission is ongoing. Based on these measurements, one WTRU may feedback information pertaining to the quality of the channel and/or transmission parameters.
  • FIG. 6 is a diagram illustrating an example of the structure of the discovery signal using beamforming. Time is shown on the horizontal axis 601 and frequency is shown on the vertical axis 602.
  • the discovery signal may need to be transmitted with different beams for beam training purposes.
  • the receiving nodes may measure the best beam and at the time of connection set up, the selected beam may be used.
  • the discovery signal may comprise blocks of OFDM symbols where each block may be transmitted with a specific first beam (i.e., Beam 1 ).
  • Each block i.e., beam
  • Each block may comprise at least one OFDM symbol that may be used for automatic gain control (AGC) 605 purposes at the receiver, at least one OFDM symbol with a reference signal (RS) 604, and at least one OFDM symbol with data 603.
  • AGC automatic gain control
  • RS reference signal
  • the last symbol of the discovery signal (e.g., in the last block, Beam N) may be left as a guard period (GP) 606.
  • GP guard period 606. Note that the exact number of AGC, RS, and data symbols in a block and their placement may be different than what is shown in the example of FIG. 6.
  • robust transmission with zero power REs may be applicable to other sequences and/or channels as well.
  • control channel(s) and shared data channel(s) may make use of this scheme.
  • FIG. 7 is a diagram illustrating an example of a physical shared feedback channel (PSFCH) transmission that may be used to transmit ACK/NACK and/or channel state information and/or other types of feedback.
  • Time may be shown in the horizontal axis 701 and frequency may be shown in the vertical axis.
  • WTRU1 may send a physical sidelink shared channel (PSSCH) to a WTRU2 in a frequency range of F1 to F2.
  • PSSCH physical sidelink shared channel
  • WTRU1 may send an ACK/NACK in the PSFCH to WTRU2 in frequency range F1 to F2.
  • FIG. 8 is a transmission diagram illustrating an example of robust ACK/NACK transmission.
  • ACK/NACK feedback from the receiver may be transmitted on an uplink control channel by transmitting a known sequence 802 within a set of sequences on a single OFDM symbol (e.g., this may be known as Format 0 PUCCH).
  • the length of the sequence 802 may be 12, and the sequence 802 that is used to provide ACK/NACK and/or SR feedback may first be upsampled 804 by a factor L.
  • upsampling by a factor L may insert L-1 zeros between each consecutive element of the sequence 802, as shown at 806.
  • the sequence 802 may be mapped 808 to subcarriers over L resource block(s). Note that it is also possible to introduce a circular shift operation after the upsampling operation.
  • a scheduling request (SR) may also be transmitted using a sequence in a similar example.
  • Feedback bits may be encoded and/or modulated before being mapped to the allocated subcarriers within a PSFCH.
  • One or more processes may be implemented for the transmission of PSFCH such as: the symbols corresponding to the feedback and reference signal may be multiplexed and mapped to the subcarriers, where the same set of multiplexed symbols may be repeated on at least two OFDM symbols; the multiplexed symbols may be upsampled before being mapped to the subcarriers; and/or the multiplexed symbols may be mapped to at least a first OFDM symbol and a reference signal sequence may be mapped to at least a second OFDM symbol, where the OFDM symbols with RS only may be transmitted before the OFDM symbols with data and the reference signal sequence on the RS-only OFDM symbol may be upsampled before being mapped to the subcarriers.
  • Format 1 PUCCFI may comprise multiple OFDM symbols. Some of these OFDM symbols may be used to transmit DMRS while others may be used to transmit a length-12 sequence. If the sequence per OFDM symbol is subject to upsampling by a factor of L, as described in relation to FIG. 8, then the corresponding RS sequence may also be upsampled with the same upsampling factor and transmitted over L*12 RBs.
  • the ACK/NACK information from multiple WTRUs may be combined, and instead of L zeros between two symbols, there may be the L/2-th zero replaced by another symbol from a different sequence for another ACK/NACK information.
  • FIG. 9 is a diagram illustrating an example pattern of robust data transmission where every other RE is set to zero power. Time is shown in OFDM symbols on the horizontal axis 901 and frequency is shown in REs on the vertical axis 902.
  • RS 904 and data 903 are indicated with patterned blocks as shown. At 921 data 903 and RS symbols 904 may be multiplexed within one OFDM symbol while at 922 data 903 symbols only are shown. If some REs are not used for transmission, then the power of the REs loaded with symbols may be boosted since there is less chance of interference as a result of the not used REs.
  • two or more antenna ports may be used, and one RS per antenna port may be required.
  • multiplexing the RSs associated with different antenna ports may be achieved in frequency domain with sparse RS allocation over the subcarriers (i.e., zero power REs).
  • FIG. 10 is a resource diagram illustrating an example of RS multiplexing with 2 RSs associated with two ports. Time may be shown in OFDM symbols on the horizontal axis 1001 and frequency may be shown in REs in the vertical axis 1002.
  • the RSs of the two ports, RS Port 1 1003 and RS Port 2 1004, as well as data 1005 may be shown in blocks with different shading.
  • the first OFDM symbol may be reserved for AGO 101 1 , and the last OFDM symbol may be used as GP 1012.
  • the density of an RS may be reduced and/or more OFDM symbols may be allocated to RS transmission.
  • a first OFDM symbol may be used to multiplex and transmit RS 1 and RS 2
  • a second OFDM symbol may be used to multiplex and transmit RS 3 and RS 4.
  • multiple RSs may be transmitted on the same set of RS by making these RSs orthogonal.
  • the RSs may be generated from the same mother sequence, and different cyclic shifts may be added to the sequences. Note that cyclic shift may correspond to linear phase in the frequency domain.
  • DMRS design may be taken into account during a DFT-s-OFDM signal processing.
  • the waveform is DFT-spread-OFDM
  • the symbols that are mapped to the IDFT inputs i.e., the subcarriers
  • the output of a DFT operation may be the output of a DFT operation.
  • FIG. 1 1 is a signal processing diagram illustrating an example of pre-DFT RS and data multiplexing in a uniform pattern.
  • data symbols 1 102b and pilot symbols 1 102a may be multiplexed before being subject to a discrete Fourier transform (DFT) operation 1 104.
  • the output of the DFT may be up-sampled 1106 to insert zeros between the DFT output symbols before being mapped 1 108 (e.g., IDFT) to the allocated subcarriers, and optionally have CP attached at 1 1 10.
  • data symbol and pilot symbol multiplexing may be uniform (e.g., every m ,h input of the DFT may be a pilot symbol where m is an integer).
  • FIG. 12 is a diagram illustrating an example of pre-DFT RS and data multiplexing. As shown, pilot symbols 1221 b and data 1221 a may be shown in alternating blocks at 1221 and may be multiplexed before the DFT processing in a non-uniform pattern where the pilot symbols may be grouped into blocks (i.e., 1222, 1223, 1224).
  • a block 1221 b may comprise pilot symbols and zeroes in one or more configurations: an RS block may comprise of a pilot symbol (e.g., a QPSK symbol used as a pilot symbol) and zeros around the pilot symbol as shown in configuration 1222; an RS block may comprise of several consecutive pilot symbols and zeros around the pilot symbols as shown in 1223; an RS block may comprise of several consecutive pilot symbols and a cyclic prefix (CP) and cyclic suffix (CS) around the pilot symbols as shown in 1224, where the CP and the CS are generated from the head and the tail of the group of consecutive pilot symbols. Note that when cyclic prefix and/or cyclic suffix exist, it may not be necessary to have zeros within the RS block.
  • CP cyclic prefix
  • CS cyclic suffix
  • a data block may comprise of a number of data symbols (e.g., modulation scheme).
  • Data and RS blocks may be multiplexed to create an input vector that would be an input to the DFT precoder.
  • RS blocks may be evenly distributed within the input vector as shown at 1221.
  • the number of RS blocks may be at least one and the size of the RS blocks may not have to be the same. For example, one large RS block may be placed at one end of the DFT input while a smaller RS block may be placed at another end of the DFT input. Additionally, only a subset of the DFT-s-OFDM symbols in a lot may have RS and data multiplexed; and the remaining DFT-s-OFDM symbols may have only data.
  • the methods applicable to determine the location and the density of the OFDM symbols with RS may be similarly applicable to determine the location and density of the DFT-s-OFDM symbols with RS.
  • the size of an RS block may be determined by at least one transmission attribute (e.g., the relative Doppler, the traffic type, the application type, the frequency selectivity, etc.).
  • a large RS block may result on better channel estimation accuracy while reducing the number of resources for data transmission.
  • high-reliability traffic with low to moderate throughput requirements may be associated with an RS block of a larger size.
  • DMRS configuration may be dynamically adapted.
  • Configuration of a reference signal may include at least one of time and frequency domain pattern (i.e., the mapping of the reference signal on the allocated subcarriers and OFDM symbols in a slot) the sequence type (e.g., Zadoff Chu or QPSK modulated bits, etc.), the specific sequence (e.g., a ZC with a given cyclic shift parameter; a QPSK modulated Gold sequence with a given initialization parameter, etc.), transmission power, and/or the like.
  • a set of possible DMRS configurations may be communicated between the nodes including at least one transmitter and one receiver.
  • a RS configuration may be a type of mode of operation with specific parameters.
  • transmission mode configuration may include RS configuration and/or other transmission characteristics.
  • robust transmission of shared data channel or control data channel may belong to the definition of a transmission mode.
  • an RS configuration, or transmission mode may relate, be associated with, or include a type of RS pattern.
  • RS configuration may be based on at least one of the traffic type and/or the application type.
  • Traffic type may be classified according to a set of receivers, such as unicast, multicast, or broadcast.
  • Application type may be determined by higher layers.
  • Application type may be based on the characteristics of the application supported by the higher layers. In one example use case sensor information feedback may need high throughout; or in another use case, an application may need very high reliability.
  • the WTRU may determine the RS configuration based on the traffic/application type and characteristics.
  • the RS configuration may be based on the channel characteristics between the transmitter and the receiver. For example, during the setup process, one or more WTRUs may determine the coverage level between them, distance between them, relative Doppler, and other information. This information may be determined by performing measurements of certain signals. For example, measurements may be made using the RS on the discovery channel, or another signal such as the synchronization signal, channel state information reference signal (CSI-RS), or the like. Based on the measurements, a WTRU may choose one type of the RS configuration. The receiving terminal may be informed of the RS configuration on the sidelink control channel. Specifically, the SCI (sidelink control information) may contain information pertaining to the RS configuration.
  • SCI sidelink control information
  • an RS configuration may be associated with a“transmission mode” or other transmission parameter configuration.
  • one RS configuration may be associated with a control channel (e.g., PSCCH), while another RS configuration may be associated with a data channel (e.g., PSSCH).
  • the same or different RS configuration may be used or configured for PSCCH and PSSCH depending on the different multiplexing of PSCCH and PSSCH.
  • PSCCH and PSSCH use frequency division multiplexing (FDM)
  • FDM frequency division multiplexing
  • TDM time division multiplexing
  • a different RS configuration may be used or configured for PSCCH and PSSCH.
  • an initial RS configuration may be determined at the time of the initial connection setup. Then, the RS configuration may be updated during the connection.
  • FIG. 13 is a flow chart illustrating an example process for an RS configuration update.
  • one or more receiving WTRUs may receive discovery signals sent by one or more transmitting WTRUs.
  • the discovery signal may be a reference signal used for measurements.
  • the receiving WTRUs that received the discovery signals from the transmitting WTRUs may perform certain measurements. For example, they may measure the relative Doppler between the transmitting and receiving WTRUs, the distance between the transmitting and receiving WTRUs, the received signal strength from the transmitting WTRU, and the like.
  • a pre-known signal I may be used. As an example, this signal could be a demodulation reference signal, or this signal could be an OFDM modulated preamble sequence.
  • the transmitting WTRU may perform the measurements, or both the receiving and the transmitting WTRUs may perform measurements.
  • certain sidelink information may also be used.
  • information from a central controller may be utilized.
  • a controller may be an infrastructure node, or in some cases another WTRU.
  • a first RS configuration may be determined by the transmitting WTRU, and the first RS configuration may be shared between the transmitting and receiving WTRUs at the establishment of a connection at 1306.
  • a transmission 1308 e.g., unicast data transmission
  • the transmitting and/or receiving WTRUs may perform measurements 1310, for example using one of the CSI-RS, DMRS, discovery signal, or the like.
  • a determination 1312 is made, by either the transmitting or receiving WTRU, whether to update the current RS configuration (e.g., transitioning from the first present RS configuration to a second RS configuration).
  • the RS configuration is updated 1314 to a second RS configuration suitable for the transmission. If the determination is negative, then the process would continue with the transmission 1308. For example, a first RS configuration may have been set to “default configuration” but during the connection relative Doppler may have increased and so the second RS configuration may have been updated to “robust configuration.” This update process (i.e., taking a measurement and determining whether to change RS configurations) may be repeated as necessary for one or more transmission(s).
  • the RS configuration may be signaled in the SCI and/or by RRC.
  • the RS configuration options may be limited. For example, 1 bit may indicate one of two DMRS resource allocation patterns (e.g., in one case, DMRS may be mapped to one OFDM symbol in a slot and in another case DMRS may be mapped to several OFDM symbols in a slot).
  • SCI and RRC based configuration may be used together to indicate an RS configuration.
  • RRC may configure a set of RS configurations and SCI may be used to choose one from this set.
  • each RU on a shared data channel may be associated with at least one RS configuration. If an RU is used for transmission, then one RS configuration associated with that RU may be used to configure the RSs within that RU.
  • FIG. 14 is a resource diagram illustrating an example of RUs. Time may be shown in slots on the horizontal axis 1401 and frequency may be shown in RBs on the vertical axis 1402. In this example, there are four RUs (i.e., 141 1 , 1412, 1413, 1414). Each RU may be associated with a specific RS configuration and/or other transmission characteristics (e.g., reference signal pattern). In general, one or more RUs may be associated with the same set of RS configurations where a set of RS configurations may contain one or more patterns.
  • the selected RS configuration may be indicated to the receiver in an SCI on the control channel where the SCI would provide the receiver with transmission parameters of the upcoming transmission in the selected RU.
  • An RU may comprise a set of resources in the time and/or frequency domain. For example, if a reference signal pattern was associated with a RU, then it may be in a reference signal of the time and/or frequency domain.
  • each RU on the control channel may be associated with an RS configuration. If an RU is used for control data transmission, then the RS configuration associated with that RU may be used to configure the RSs within that RU.
  • one or more control channel parameters may be associated with an RS configuration for the shared data channel.
  • the CORESET and/or the aggregation levels may be associated with an RS configuration. As an example, if the control information is transmitted on a first CORESET, then this may imply a first RS configuration on the shared data channel scheduled with this control information. If the control information is transmitted on a second CORESET, then this may imply a second RS configuration on the shared data channel scheduled with this control information.
  • a WTRU may be configured with one or more candidate RUs and a subset of the assigned RUs may be selected for transmission.
  • one or more candidate RUs may comprise a resource pool; as discussed herein, one or more RUs a resource pool may be interchangeable.
  • Each RU may be associated with transmission characteristics that may include traffic type, application type, reliability, quality of service requirements, latency, estimated activity within the selected RU (e.g., interference level), and the like.
  • an RU when an RU is associated with a pattern, there may be a set of subcarriers/OFDM symbols in a slot; for example, one pattern could be every other subcarrier in 1 OFDM symbol only, and one pattern could be every other subcarrier in 4 OFDM symbols in a slot.
  • FIG. 15 is a diagram illustrating one or more candidate RUs organized in resource pools.
  • Each resource pools contains a set of RUs.
  • Each RU may be associated with at least one RS configuration (e.g., mode, design, pattern).
  • RS configuration e.g., mode, design, pattern
  • RU151 1 may be similar to RU1521
  • RU1512 may be similar to RU1522
  • RU1513 may be similar to RU1523.
  • Different types of traffic may be better suited for specific subsets of RUs (i.e., a specific DMRS pattern).
  • RU151 1 , RU1521 , RU1512, RU1522, RU1513, and RU1523 may be suited for unicast with low, medium, and high speeds.
  • RU1513, RU1523, RU1514, and RU1524 may be suited for groupcast with low and high speeds.
  • RU1514 and RU1524 may be suited for broadcast with high reliability.
  • the WTRU may select one or more RUs based on transmission characteristics. It may be possible to choose two or more RUs where each RU may be used to transmit different types of data. As an example, a WTRU may have data pertaining to a high-reliability application and data pertaining to a high-throughout application. The WTRU may choose two RUs where one RU may be used to transmit the first type of data and the other RU may be used to transmit the second type of data. Depending on the RU, transmission parameters may be determined. One of the transmission parameters may be reference signal parameters (e.g. DMRS and PTRS parameters). [0157] FIG.
  • 16 is a flow chart illustrating an example process for avoiding unnecessary DMRS overhead from the perspective of a transmitting WTRU.
  • the WTRU may receive the configuration of one or more resource pools and select a resource pool (e.g., resource pool 1520).
  • the WTRU may receive information associated with a traffic type (e.g., unicast, groupcast, broadcast) from higher layers.
  • the WTRU may determine one or more RS configurations (i.e., DMRS in this example), which is associated with one or more DMRS patterns based on the information associated with the received traffic type and other parameters known or received by the WTRU (e.g., speed, reliability, priority, quality of service, etc.).
  • the WTRU may send control information (e.g., SCI) on a control channel (e.g., PSCCH) with an indication of the DMRS pattern (e.g., RU).
  • control information e.g., SCI
  • PSCCH control channel
  • the WTRU may transmit in the PSSCH using the indicated DMRS pattern. It may follow, although not shown in FIG. 16, that the WTRU may also receive transmissions that were made using the indicated DMRS pattern. Further, the WTRU may make data transmissions using the DMRS pattern.
  • the RS configuration may be updated, using techniques as disclosed herein.
  • RUs may be allocated based on a sensing procedure, a specific RU with an associated RS configuration may not be available. In this case, the RS configuration associated with a resource pool may be overwritten and the WTRU may use another RS configuration. The receiver may get a message indicating this preference on the control channel.
  • a WTRU may broadcast on the discovery channel some of its required transmission parameters. For example, an RS configuration may be one of these. Such information may be explicitly broadcasted (i.e., there is a parameter in the discovery message), or it may be implicitly broadcasted (i.e., another parameter in the discovery message may imply the associated RS configuration). For example, high reliability may be associated with time-domain denser RSs.
  • a first WTRU may choose a preferred set of time and frequency resources on which a discovery signal/message is going to be transmitted.
  • the discovery signal may comprise of information about the WTRU where this information may contain certain PHY layer configuration preferences, such as reference signal configuration. It may also be possible to deduce the RS configuration from another preference. For example, traffic type, application type and/or ID, WTRU ID, or the like within the discovery information. WTRUs receiving this information and those that initiate a communication with the first WTRU may use the preferred RS configuration within the transmission. While this procedure has been described in terms of RS, it may be applicable similarly to other PHY related configuration, such as MIMO configuration.
  • WTRUs may first exchange setup messages before starting transmission. These messages, for example, may be request-to- transmit (RTS), clear-to-transmit (CTS).
  • RTS request-to- transmit
  • CTS clear-to-transmit
  • a first WTRU may choose a preferred set of time and frequency resources on which RTS message is going to be transmitted. WTRUs receiving this information and those that want to initiate a communication with the first WTRU may send back CTS.
  • the CTS may be transmitted on the same RU as the RTS was received.
  • the CTS may contain information about preferred PHY configuration, for example, RS configuration.
  • the first WTRU may initiate data transmission with the preferred configuration in the CTS message. While this procedure has been described in terms of RS, it may be applicable similarly to other PHY related configuration, such as MIMO configuration.
  • the RS configuration may depend on the application type. For example, in the vehicle platooning use cases, target WTRUs for a groupcast may be among the platoon vehicle members, where the relative speed among those platoon vehicle members is very low. Hence, the ICI issue may no longer exist. Therefore, some legacy RS schemes may be applied. After joining a vehicle platoon, a platoon member may automatically switch to a legacy RS scheme if it is more efficient or for some other reason, such as a received indication.
  • RS design may be adapted for specific use cases, such as platooning.
  • WTRUs When WTRUs are traveling in the form of a platoon, one WTRU may be selected as a platoon leader. Other WTRUs may join or leave the platoon based on their needs.
  • a platoon leader may be selected based on configuration and/or a set of criteria. Once the platoon leader is selected, other WTRUs in the platoon may become followers. The platoon leader may have higher priority. Also, the platoon leader may manage the followers in the platoon.
  • Followers may want to communicate with the platoon leader first, unless the platoon leader is not accessible, then followers may communicate with other followers to reach the platoon leader. Since the platoon leader has higher priority, it may require more accurate and higher reliable communications with all the followers.
  • RS design may be prioritized for a platoon leader over the platoon followers.
  • the platoon leader may employ an RS configuration with higher density design while platoon followers may use a looser RS configuration with normal density. This may be done at the cost of slightly increased system overhead.
  • the RS configurations with a higher density and RS configurations with sparser density may be employed such that the total RS overhead is maintained at the same level in the system.
  • the platoon lead may use one RS configuration with higher density for enhanced performance and followers may use RS configuration with lower density.
  • RS adaptation such as for platooning, may be performed either semi-statically or dynamically.
  • FIG. 17 is a flow chart illustrating an example of RS configuration adaption for platooning.
  • a WTRU may receive RS configuration for platooning which may include transmission mode(s), RS patterns, zero-power or non-zero power settings, interleaving or non-interleaved layouts, density or sparsity, and/or the like.
  • the WTRU may join the platoon, afterwards at 1706, the WTRU may synchronize with the platoon leader or follower(s).
  • the WTRU may determine RS configuration based on the WTRU synchronization status associated with the platoon.
  • synchronization status may be synchronized platoon leader, follower, etc.
  • the WTRU may adapt RS configuration and perform channel estimation accordingly based on the determined RS configuration.
  • the WTRU may receive the data based on the channel estimation using the adapted RS configuration.
  • RS design adaptation for zero-power adjacent RE.
  • FIG. 18 is a resource diagram illustrating an example of zero-power adjacent RE based DRMS and PTRS pattern.
  • Time may be shown in OFDM symbols in the horizontal axis 1801 , and frequency may be shown in REs in the vertical axis 1802.
  • the first OFDM symbol may be reserved for AGO 181 1 , and the last OFDM symbol may be used as GP 1812.
  • the DMRS 1804 may occupy OFDM symbols 1821 with zero-power adjacent REs.
  • the data 1803 may follow, until two instances of OFDM symbols 1822 where PTRS occur with adjacent zero-power REs.
  • there there may be an RS configuration indication within a reservation signal.
  • a WTRU may transmit a reservation signal to reserve transmission resources.
  • a reservation signal may be composed of coded bits and may be used to inform listening WTRUs of the resources that the transmitting WTRU is planning to reserve in a later time for its own transmission.
  • the reservation signal may be used to reserve resources for a scheduling assignment (SA) and data transmission on the physical sidelink shared channel.
  • SA scheduling assignment
  • FIG. 19 is a collection of transmission diagrams illustrating examples of reservation signals.
  • time is shown on the horizontal axis (e.g., 1901 , 1921 ) and frequency is shown on the vertical axis (e.g., 1902, 1922).
  • Example 1900 shows a configuration where a WTRU transmits the reservation signal on a set of frequency resources in slot n.
  • the reservation signal may be transmitted on one or more OFDM symbols within slot n.
  • the SA may comprise of at least two stages (e.g., Stage-1 SA, Stage-2 SA). At least one of the stages may be decoded such that it may be decoded by listening WTRUs, and this stage may be used as a reservation signal. Each stage may be transmitted within the frequency range of F1 to F2.
  • the WTRU transmitting the reservation signal may indicate within this signal the RS configuration that is going to be used for the transmission on the reserved resources.
  • One indicated DMRS configuration may correspond to the DMRS configuration in the PSSCH, the SA (or stage 2 SA if the reservation signal is stage 1 SA) and/or for both SA (or stage 2 SA if the reservation signal is stage 1 SA) and the PSSCH.
  • traffic type may be indicated within the reservation signal and a RS configuration may be associated with a traffic type.
  • the reservation signal may reserve the resources for one of unicast traffic (i.e., RS configuration 1 ), broadcast traffic (i.e., RS configuration 2), groupcast traffic with ACK/NACK feedback (i.e., RS configuration 3), or groupcast traffic without ACK/NACK feedback (i.e., RS configuration 4).
  • broadcast traffic may be associated with an RS configuration that requires dense RS pattern in time and/or frequency and unicast traffic may be associated with less dense RS pattern in time and/or frequency (e.g., dense pattern: reference signal is mapped to every other subcarrier over 4 OFDM symbols; sparse pattern: reference signal is mapped to every other subcarrier in one OFDM symbol).
  • WTRUs that detect and decode the reservation signals may perform the necessary receive algorithms based on the indicated RS configuration. For example, they may perform channel estimation, channel state information computation, and/or interference measurements using the indicated RS configuration.
  • Each RS configuration may be associated with a specific time/frequency pattern for the RS; so WTRUs receiving this indication would be aware of the REs carrying RS in a slot.
  • Information carried in signals such as a reservation signal, discovery signals, or the like may have to be detected and decoded by numerous WTRUs listening to these signals. Therefore, WTRUs may also be able to know the DMRS transmitted together with these signals so that they can estimate the channel and perform equalization.
  • FIG. 20 illustrates a set of resource pools and example time/frequency locations of potential reservation and/or discovery signals.
  • Time may be shown on the horizontal axis 2001 and frequency may be shown on the vertical axis 2002.
  • each instance of the reservation signal 2003 may comprise three (3) OFDM symbols, where the first of the OFDM symbols may be used for DMRS 2004.
  • the reference signal may be generated by modulating a pseudo-random sequence as discussed herein.
  • the pseudo-random bit sequence may be generated as a function of the resource pool in which the corresponding DMRS is transmitted, for example the resource pool index.
  • the resource pool index may be pre-determined or may be computed from known parameters (e.g., the time and frequency resources of the resource pool).
  • the bit sequence may, in general, be a function one or more of parameters, such as the ID, the slot ID, and/or the frequency resources of the resource pool in which the corresponding DMRS is transmitted.
  • channel station information reference signals may be used.
  • CSI-RS channel station information reference signals
  • the second WTRU may be expected to perform measurements and feedback some type of CSI to the first WTRU.
  • the second WTRU may perform measurements and may determine the quality of the channel from the first WTRU to the second WTRU based on these measurements.
  • the configuration of the CSI-RS may be determined by the traffic type and/or the application type, where the configuration may include at least one of time/frequency density and location, transmit power, or the like.
  • the traffic and/or the application type may be determined during the connection set-up and the associated CSI-RS may be used during the PSSCH transmission.
  • a very high throughput real-time traffic type may be associated with denser CSI-RS rather than a low throughput traffic type.
  • each resource unit, or resource pool may be associated with a CSI- RS configuration.
  • the associated CSI-RS may be used.
  • the CSI-RS may be mapped to the subcarriers of an OFDM symbol in an interleaved fashion.
  • the CSI-RS may be mapped to every m ,h subcarrier where m, also referred to as the interleaving coefficient, may be an integer larger than one.
  • the interleaving coefficient may be determined by at least one physical layer attribute (e.g., the subcarrier spacing). For example, for smaller subcarrier spacing, a higher interleaving coefficient may be utilized while for larger subcarrier spacing a lower interleaving coefficient may be utilized.
  • An interleaved mapping into the IDFT of an OFDM modulator generates a repeated time domain signal where the number of repetitions is equal to the interleaving factor. A high interleaving factor may result in a more efficient CSI and beam measurement for lower subcarrier spacing.
  • the discovery channel may comprise a set of OFDM symbols where the information carried by the set of OFDM symbols may be the same. For example, as shown in FIG. 6, one set may comprise four OFDM symbols.
  • signals in the sets of OFDM symbols may also be identical (e.g., the reference signals).
  • Each set of the OFDM symbols may be transmitted with a different beam.
  • the preferred beam may be determined based on certain measurements. For example, assume WTRU 1 transmits the discovery channel with M different beams and WTRU 2 receives and measures the quality of these beams, and determines at least one preferred beam.
  • WTRU 2 initiates a connection to WTRU 1 , it may use the preferred beam, or one of the preferred beams, determined during the discovery channel reception. For example, the initial PSCCH and/or the PSSCH may be transmitted using the preferred beam.
  • the initially preferred beam may be updated based on the CSI-RS measurements performed within the PSSCH.
  • several different CSI-RS may be transmitted within the PSSCH where each one may be precoded with a different beamforming vector. Then, the preferred beam may be fed back (i.e., feedback) by the receiver.
  • WTRU Wireless Fidelity
  • UE User Equipment
  • terminal terminal

Abstract

La présente invention concerne des procédés, des systèmes et des dispositifs pour réduire des interférences entre porteuses sur la base de la conception et de paramètres d'un signal de référence (RS). Une unité d'émission-réception sans fil (WTRU) peut recevoir une configuration d'un ou de plusieurs groupes de ressources. Chaque groupe de ressources peut être associé à un ensemble de configurations de signaux de référence de démodulation (DMRS). Chaque configuration de DMRS peut être associée à un modèle de DMRS. La WTRU peut recevoir, en provenance d'une couche supérieure, des informations associées à un type de trafic et, sur la base de ces informations, déterminer, d'après l'ensemble de configurations de DMRS, un modèle de DMRS à utiliser aux fins d'émission. La WTRU peut émettre une indication de ce modèle de DMRS déterminé sur un canal de commande (par exemple, des informations de commande de liaison latérale). La WTRU peut ensuite procéder à l'utilisation de ce modèle de DMRS pour une émission de données. La WTRU peut recevoir une réponse à l'émission de données, une réponse étant émise à l'aide du modèle de DMRS. La WTRU peut mettre à jour la configuration de DMRS si nécessaire.
PCT/US2019/053284 2018-09-26 2019-09-26 Conception de signal de référence pour v2x WO2020069207A1 (fr)

Applications Claiming Priority (6)

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US201862736829P 2018-09-26 2018-09-26
US62/736,829 2018-09-26
US201862753382P 2018-10-31 2018-10-31
US62/753,382 2018-10-31
US201962790399P 2019-01-09 2019-01-09
US62/790,399 2019-01-09

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US11425690B2 (en) * 2019-08-14 2022-08-23 Qualcomm Incorporated Spatial resource pool techniques for multiple concurrent transmissions in sidelink wireless communications
US11569961B2 (en) 2019-08-30 2023-01-31 Huawei Technologies Co., Ltd. Reference signaling overhead reduction apparatus and methods
WO2023075976A1 (fr) * 2021-10-29 2023-05-04 Qualcomm Incorporated Groupes de ressources comportant des ressources de signal de référence
WO2024011030A1 (fr) * 2022-07-07 2024-01-11 Qualcomm Incorporated Motifs de signal de référence de démodulation modifiés pour multiplexage par répartition orthogonale de la fréquence

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11425690B2 (en) * 2019-08-14 2022-08-23 Qualcomm Incorporated Spatial resource pool techniques for multiple concurrent transmissions in sidelink wireless communications
US11258565B2 (en) * 2019-08-30 2022-02-22 Huawei Technologies Co., Ltd. Sparse reference signal-related signaling apparatus and methods
US11569961B2 (en) 2019-08-30 2023-01-31 Huawei Technologies Co., Ltd. Reference signaling overhead reduction apparatus and methods
WO2023075976A1 (fr) * 2021-10-29 2023-05-04 Qualcomm Incorporated Groupes de ressources comportant des ressources de signal de référence
WO2024011030A1 (fr) * 2022-07-07 2024-01-11 Qualcomm Incorporated Motifs de signal de référence de démodulation modifiés pour multiplexage par répartition orthogonale de la fréquence

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