WO2020024262A1 - Génération de signal de référence de démodulation dans des systèmes d'accès multiple non orthogonal de liaison montante sans autorisation - Google Patents

Génération de signal de référence de démodulation dans des systèmes d'accès multiple non orthogonal de liaison montante sans autorisation Download PDF

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Publication number
WO2020024262A1
WO2020024262A1 PCT/CN2018/098531 CN2018098531W WO2020024262A1 WO 2020024262 A1 WO2020024262 A1 WO 2020024262A1 CN 2018098531 W CN2018098531 W CN 2018098531W WO 2020024262 A1 WO2020024262 A1 WO 2020024262A1
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Prior art keywords
pool
dmrs
random
sequence
zadoff
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PCT/CN2018/098531
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English (en)
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Qiaoyu Li
Chao Wei
Hao Xu
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Qualcomm Incorporated
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Priority to PCT/CN2018/098531 priority Critical patent/WO2020024262A1/fr
Publication of WO2020024262A1 publication Critical patent/WO2020024262A1/fr

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    • 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
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency

Definitions

  • aspects of the present disclosure generally relate to wireless communication, and more particularly to techniques and apparatuses for demodulation reference signal (DMRS) generation in grant-free uplink non-orthogonal multiple access (NOMA) systems.
  • DMRS demodulation reference signal
  • Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts.
  • Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) .
  • multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) .
  • LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP) .
  • UMTS Universal Mobile Telecommunications System
  • a wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs) .
  • a user equipment (UE) may communicate with a base station (BS) via the downlink and uplink.
  • the downlink (or forward link) refers to the communication link from the BS to the UE
  • the uplink (or reverse link) refers to the communication link from the UE to the BS.
  • a BS may be referred to as a Node B, a gNB, an access point (AP) , a radio head, a transmit receive point (TRP) , a new radio (NR) BS, a 5G Node B, and/or the like.
  • New radio which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP) .
  • NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL) , using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM) ) on the uplink (UL) , as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.
  • OFDM orthogonal frequency division multiplexing
  • SC-FDM e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)
  • DFT-s-OFDM discrete Fourier transform spread OFDM
  • MIMO multiple-input multiple-output
  • a method for wireless communication may include generating a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission; and transmitting the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a UE for wireless communication may include a memory and one or more processors configured to generate a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission; and transmit the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a non-transitory computer-readable medium may store one or more instructions for wireless communication.
  • the one or more instructions when executed by one or more processors of a UE, may cause the one or more processors to generate a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission; and transmit the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • an apparatus for wireless communication may include means for generating a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission; and means for transmitting the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a method for wireless communication may include generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; generating the DMRS based at least in part on the random sequence; and transmitting the DMRS in a set of resource elements.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a UE for wireless communication may include a memory and one or more processors configured to generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; generate the DMRS based at least in part on the random sequence; and transmit the DMRS in a set of resource elements.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a non-transitory computer-readable medium may store one or more instructions for wireless communication.
  • the one or more instructions when executed by one or more processors of a UE, may cause the one or more processors to generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; generate the DMRS based at least in part on the random sequence; and transmit the DMRS in a set of resource elements.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • an apparatus for wireless communication may include means for generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; means for generating the DMRS based at least in part on the random sequence; and means for transmitting the DMRS in a set of resource elements.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a method for wireless communication may include generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; and generating or transmitting the DMRS based at least in part on the random sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a UE for wireless communication may include a memory and one or more processors configured to generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; and generate or transmit the DMRS based at least in part on the random sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • a non-transitory computer-readable medium may store one or more instructions for wireless communication.
  • the one or more instructions when executed by one or more processors of a UE, may cause the one or more processors to generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; and generate or transmit the DMRS based at least in part on the random sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • an apparatus for wireless communication may include means for generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; and means for generating or transmitting the DMRS based at least in part on the random sequence.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with various aspects of the present disclosure.
  • Fig. 2 is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communication network, in accordance with various aspects of the present disclosure.
  • UE user equipment
  • Fig. 3 is a block diagram conceptually illustrating an example slot format with a normal cyclic prefix, in accordance with various aspects of the present disclosure.
  • Figs. 4-7 are diagrams illustrating examples of demodulation reference signal (DMRS) generation in grant-free uplink non-orthogonal multiple access (NOMA) systems, in accordance with various aspects of the present disclosure.
  • DMRS demodulation reference signal
  • Figs. 8-10 are diagrams illustrating example processes performed, for example, by a user equipment, in accordance with various aspects of the present disclosure.
  • a UE may transmit an uplink communication without first receiving an uplink grant that schedules transmission of the uplink communication.
  • the UE may transmit a demodulation reference signal (DMRS) to the base station.
  • DMRS demodulation reference signal
  • each UE may randomly select or generate a DMRS for transmission to the base station.
  • Some communication system designs support a fixed DMRS that is indicated to a UE by the base station, and the UE uses this fixed DMRS. In this case, the UE does not have the ability to randomly select and/or generate a DMRS, thereby leading to incapability of the UE and the base station to support grant-free NOMA transmission.
  • Some techniques and apparatuses described herein enable grant-free NOMA transmission by permitting a UE to randomly generate and/or transmit DMRS to the base station. For example, some techniques and apparatuses described herein permit a UE to generate a random sequence using a randomly selected parameter from a pool of parameters (e.g., a pool of seeds, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, a pool of cyclic shift values, and/or the like) , and to generate and/or transmit DMRS based at least in part on the random sequence. In this way, DMRS collisions may be reduced and CSI estimation may be improved, thereby leading to more accurate CSI estimations and improving network performance.
  • a pool of parameters e.g., a pool of seeds, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, a pool of cyclic shift values, and/or the like
  • aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.
  • Fig. 1 is a diagram illustrating a network 100 in which aspects of the present disclosure may be practiced.
  • the network 100 may be an LTE network or some other wireless network, such as a 5G or NR network.
  • Wireless network 100 may include a number of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities.
  • a BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, a NR BS, a Node B, a gNB, a 5G node B (NB) , an access point, a transmit receive point (TRP) , and/or the like.
  • Each BS may provide communication coverage for a particular geographic area.
  • the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.
  • a BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell.
  • a macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription.
  • a pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription.
  • a femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG) ) .
  • a BS for a macro cell may be referred to as a macro BS.
  • a BS for a pico cell may be referred to as a pico BS.
  • a BS for a femto cell may be referred to as a femto BS or a home BS.
  • a BS 110a may be a macro BS for a macro cell 102a
  • a BS 110b may be a pico BS for a pico cell 102b
  • a BS 110c may be a femto BS for a femto cell 102c.
  • a BS may support one or multiple (e.g., three) cells.
  • eNB base station
  • NR BS NR BS
  • gNB gNode B
  • AP AP
  • node B node B
  • 5G NB 5G NB
  • cell may be used interchangeably herein.
  • a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS.
  • the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the access network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and/or the like using any suitable transport network.
  • Wireless network 100 may also include relay stations.
  • a relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS) .
  • a relay station may also be a UE that can relay transmissions for other UEs.
  • a relay station 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d.
  • a relay station may also be referred to as a relay BS, a relay base station, a relay, etc.
  • Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in wireless network 100.
  • macro BSs may have a high transmit power level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 Watts) .
  • a network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs.
  • Network controller 130 may communicate with the BSs via a backhaul.
  • the BSs may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.
  • UEs 120 may be dispersed throughout wireless network 100, and each UE may be stationary or mobile.
  • a UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, etc.
  • a UE may be a cellular phone (e.g., a smart phone) , a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet) ) , an entertainment device (e.g., a music or video device, or a satellite radio) , a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.
  • PDA personal digital assistant
  • WLL wireless local loop
  • MTC and eMTC UEs include, for example, robots, drones, remote devices, such as sensors, meters, monitors, location tags, etc., that may communicate with a base station, another device (e.g., remote device) , or some other entity.
  • a wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link.
  • Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE) .
  • UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and/or the like.
  • any number of wireless networks may be deployed in a given geographic area.
  • Each wireless network may support a particular RAT and may operate on one or more frequencies.
  • a RAT may also be referred to as a radio technology, an air interface, etc.
  • a frequency may also be referred to as a carrier, a frequency channel, etc.
  • Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs.
  • NR or 5G RAT networks may be deployed.
  • a scheduling entity e.g., a base station
  • the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity.
  • Base stations are not the only entities that may function as a scheduling entity. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs) . In this example, the UE is functioning as a scheduling entity, and other UEs utilize resources scheduled by the UE for wireless communication.
  • a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may optionally communicate directly with one another in addition to communicating with the scheduling entity.
  • P2P peer-to-peer
  • mesh network UEs may optionally communicate directly with one another in addition to communicating with the scheduling entity.
  • a scheduling entity and one or more subordinate entities may communicate utilizing the scheduled resources.
  • two or more UEs 120 may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another) .
  • the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like.
  • V2X vehicle-to-everything
  • the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.
  • Fig. 1 is provided merely as an example. Other examples are possible and may differ from what was described with regard to Fig. 1.
  • Fig. 2 shows a block diagram of a design 200 of base station 110 and UE 120, which may be one of the base stations and one of the UEs in Fig. 1.
  • Base station 110 may be equipped with T antennas 234a through 234t
  • UE 120 may be equipped with R antennas 252a through 252r, where in general T ⁇ 1 and R ⁇ 1.
  • a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS (s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) , etc. ) and control information (e.g., CQI requests, grants, upper layer signaling, etc. ) and provide overhead symbols and control symbols.
  • MCS modulation and coding schemes
  • Transmit processor 220 may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS) ) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS) ) .
  • a transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream.
  • TX transmit
  • MIMO multiple-input multiple-output
  • Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream.
  • Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal.
  • T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.
  • the synchronization signals can be generated with location encoding to convey additional information.
  • antennas 252a through 252r may receive the downlink signals from base station 110 and/or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively.
  • Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples.
  • Each demodulator 254 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols.
  • a MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols.
  • a receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280.
  • a channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , etc.
  • RSRP reference signal received power
  • RSSI received signal strength indicator
  • RSRQ reference signal received quality
  • CQI channel quality indicator
  • one or more components of UE 120 may be included in a housing.
  • a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, etc. ) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc. ) , and transmitted to base station 110.
  • modulators 254a through 254r e.g., for DFT-s-OFDM, CP-OFDM, etc.
  • the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120.
  • Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240.
  • Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244.
  • Network controller 130 may include communication unit 294, controller/processor 290, and memory 292.
  • Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform one or more techniques associated with DMRS generation in grant-free uplink NOMA systems, as described in more detail elsewhere herein.
  • controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform or direct operations of, for example, process 800 of Fig. 8, process 900 of Fig. 9, process 1000 of Fig. 10, and/or other processes as described herein.
  • Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively.
  • a scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.
  • the stored program codes when executed by processor 280 and/or other processors and modules at UE 120, may cause the UE 120 to perform operations described with respect to process 800 of Fig. 8, process 900 of Fig. 9, process 1000 of Fig. 10, and/or other processes as described herein.
  • a scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.
  • UE 120 may include means for generating a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission; means for transmitting the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence; and/or the like.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • UE 120 may include means for generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; means for generating the DMRS based at least in part on the random sequence; means for transmitting the DMRS in a set of resource elements; and/or the like.
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • UE 120 may include means for generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values; means for generating or transmitting the DMRS based at least in part on the random sequence; and/or the like.
  • such means may include one or more components of UE 120 described in connection with Fig. 2.
  • While blocks in Fig. 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components.
  • the functions described with respect to the transmit processor 264, the receive processor 258, and/or the TX MIMO processor 266 may be performed by or under the control of processor 280.
  • Fig. 2 is provided merely as an example. Other examples are possible and may differ from what was described with regard to Fig. 2.
  • Fig. 3 shows an example slot format 310 with a normal cyclic prefix.
  • the available time frequency resources may be partitioned into resource blocks.
  • Each resource block may cover a set to of subcarriers (e.g., 12 subcarriers) in one slot and may include a number of resource elements.
  • Each resource element may cover one subcarrier in one symbol period (e.g., in time) and may be used to send one modulation symbol, which may be a real or complex value.
  • New radio may refer to radios configured to operate according to a new air interface (e.g., other than Orthogonal Frequency Divisional Multiple Access (OFDMA) -based air interfaces) or fixed transport layer (e.g., other than Internet Protocol (IP) ) .
  • NR may utilize OFDM with a CP (herein referred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDM on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD.
  • OFDM Orthogonal Frequency Divisional Multiple Access
  • IP Internet Protocol
  • NR may, for example, utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD.
  • CP-OFDM OFDM with a CP
  • DFT-s-OFDM discrete Fourier transform spread orthogonal frequency-division multiplexing
  • NR may include Enhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g., 80 megahertz (MHz) and beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 60 gigahertz (GHz) ) , massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra reliable low latency communications (URLLC) service.
  • eMBB Enhanced Mobile Broadband
  • mmW millimeter wave
  • mMTC massive MTC
  • URLLC ultra reliable low latency communications
  • NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 60 or 120 kilohertz (kHz) over a 0.1 millisecond (ms) duration.
  • Each radio frame may include 40 slots and may have a length of 10 ms. Consequently, each slot may have a length of 0.25 ms.
  • Each slot may indicate a link direction (e.g., DL or UL) for data transmission and the link direction for each slot may be dynamically switched.
  • Each slot may include DL/UL data as well as DL/UL control data.
  • NR may support a different air interface, other than an OFDM-based interface.
  • NR networks may include entities such central units or distributed units.
  • Fig. 3 is provided as an example. Other examples are possible and may differ from what was described with regard to Fig. 3.
  • a UE 120 may transmit an uplink communication without first receiving an uplink grant that schedules transmission of the uplink communication.
  • the UE 120 may transmit a demodulation reference signal (DMRS) to the base station 110.
  • DMRS demodulation reference signal
  • each UE 120 may randomly select or generate a DMRS for transmission to the base station 110.
  • Some communication system designs support a fixed DMRS that is indicated to a UE 120 by the base station 110, and the UE 120 uses this fixed DMRS. In this case, the UE 120 does not have the ability to randomly select and/or generate a DMRS, thereby leading to incapability of the UE 120 and the base station 110 to support grant-free NOMA transmission.
  • Some techniques and apparatuses described herein enable grant-free NOMA transmission by permitting a UE 120 to randomly generate and/or transmit DMRS to the base station 110.
  • some techniques and apparatuses described herein permit a UE 120 to generate a random sequence using a randomly selected parameter from a pool of parameters (e.g., a pool of seeds, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, a pool of cyclic shift values, and/or the like) , and to generate and/or transmit DMRS based at least in part on the random sequence.
  • a pool of parameters e.g., a pool of seeds, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, a pool of cyclic shift values, and/or the like
  • DMRS collisions may be reduced and CSI estimation may be improved, thereby leading to more accurate CSI estimations and improving network performance. Additional details are described below.
  • Fig. 4 is a diagram illustrating an example 400 of DMRS generation in grant-free uplink NOMA systems, in accordance with various aspects of the present disclosure.
  • a base station 110 may broadcast information for obtaining a pool of parameters.
  • the pool of parameters may be associated with generating and/or transmitting a DMRS for a grant-free uplink NOMA transmission, as described in more detail below.
  • the information may be broadcast in system information (e.g., in a system information block (SIB) , a master information block (MIB) , and/or the like) , in a radio resource control (RRC) message, and/or the like.
  • the information may identify the pool of parameters (e.g., in a list and/or the like) . Additionally, or alternatively, the information may be used to generate the pool of parameters (e.g., by applying one or more calculations to the information) .
  • the pool of parameters may be cell-specific, and different cells may be associated with different pools of parameters.
  • a UE 120 may determine a pool of parameters associated with generating and/or transmitting grant-free uplink NOMA DMRS. In some aspects, the UE 120 may determine the pool of parameters based at least in part on the information broadcast by the base station 110, as described above.
  • the pool of parameters may include a pool of seeds (e.g., to be used for resource element phase rotation, as described elsewhere herein) , a pool of scrambling identifiers, a pool of Zadoff-Chu (ZC) group identifiers, a pool of cyclic shift values, and/or the like.
  • the UE 120 may randomly select a parameter from the pool of parameters. For example, the UE 120 may randomly select a seed, a scrambling identifier, a ZC group identifier, a cyclic shift value, and/or the like. Additional details regarding these parameters are described below in connection with Figs. 5-7.
  • the UE 120 may generate a random sequence using the randomly selected parameter. For example, the UE 120 may generate a random binary sequence based at least in part on a randomly selected seed. As another example, the UE 120 may generate a random binary sequence based at least in part on a randomly selected scrambling identifier. As another example, the UE 120 may generate a random ZC sequence based at least in part on a randomly selected ZC group identifier and/or a randomly selected cyclic shift value. Additional details regarding random sequence generation are described below in connection with Figs. 5-7.
  • the UE 120 may generate and/or transmit a DMRS (e.g., a single DMRS or multiple DMRS) based at least in part on the random sequence. Additional details regarding DMRS generation and/or transmission using random sequences are described below in connection with Figs. 5-7.
  • a DMRS e.g., a single DMRS or multiple DMRS
  • the base station 110 may receive the DMRS, and may communicate with the UE 120 based at least in part on the DMRS.
  • the base station 110 may use the DMRS for coherent demodulation of communications (e.g., NOMA communications, grant-free uplink NOMA communications, and/or the like) received from the UE 120.
  • the base station 110 may use the DMRS to estimate channel state information (CSI) for the UE 120, and may configure communications with or by the UE 120 based at least in part on the CSI.
  • CSI channel state information
  • the UE 120 may reduce a likelihood of DMRS collisions with other UEs, thereby improving CSI estimation at the base station 110 and improving network performance.
  • a pool of parameters e.g., a pool of seeds, a pool of scrambling identifiers, a pool of ZC group identifiers, a pool of cyclic shift values, and/or the like.
  • Fig. 4 is provided as an example. Other examples are possible and may differ from what was described with respect to Fig. 4.
  • Fig. 5 is a diagram illustrating another example 500 of DMRS generation in grant-free uplink NOMA systems, in accordance with various aspects of the present disclosure.
  • a base station 110 may broadcast information for obtaining a pool of parameters associated with generating and/or transmitting DMRS for grant-free uplink NOMA communications, as described above in connection with Fig. 4.
  • a UE 120 may determine the pool of parameters, as described above in connection with Fig. 4. In some aspects, the UE 120 may determine the pool of parameters based at least in part on the information broadcast by the base station 110.
  • the pool of parameters may include a pool of seeds to be used for resource element phase rotation.
  • the UE 120 may randomly select a seed from the pool of seeds.
  • the pool of seeds may be cell-specific, and different cells may be associated with different pools of seeds, thereby reducing a likelihood of inter-cell interference for DMRS transmissions.
  • the UE 120 may generate a random binary sequence, associated with transmission of the DMRS, using the randomly selected seed.
  • the UE 120 may generate the random binary sequence based at least in part on the randomly selected seed and a subframe index of a subframe in which the DMRS is to be transmitted.
  • the UE 120 may generate an initial binary sequence c init as follows, where o represents a value of the random seed, N represents the subframe index of the subframe in which the DMRS is to be transmitted, and represents a cell identity of a cell on which the UE 120 is camped:
  • the UE 120 may then generate the random binary sequence c (n) (e.g., a generic pseudo-random sequence) using the initial binary sequence c init and a Gold sequence (e.g., a length-31 Gold sequence) , such as by using c init as input to generate a pseudo-random sequence according to a telecommunication standard (e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like) .
  • a telecommunication standard e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like
  • the UE 120 may generate and/or transmit a DMRS (e.g., a single DMRS or multiple DMRS) based at least in part on the random binary sequence.
  • a DMRS e.g., a single DMRS or multiple DMRS
  • the UE 120 may transmit the DMRS in a set of resource elements, and the UE 120 may rotate a phase of one or more of those resources elements (e.g., at least one resource element in the set, multiple resource elements in the set, or all resource elements in the set) based at least in part on the random binary sequence.
  • a set of bits (e.g., a set of consecutive bits) included in the random binary sequence may correspond to a resource element in the set of resource elements, and the value (s) of the set of bits may be used by the UE 120 to determine a phase rotation to be applied to the resource element.
  • a first set of two consecutive bits may be used to determine a phase rotation for a first resource element in the set of resource elements, shown as RE1.
  • the first value of 00 may correspond to a first phase rotation of 1
  • the UE 120 may apply this first phase rotation to the first resource element (e.g., by transmitting the DMRS in RE1 on a rotated modulation constellation) .
  • a second set of two consecutive bits shown as 01
  • the second value of 01 may correspond to a second phase rotation of -1, and the UE 120 may apply this second phase rotation to the second resource element.
  • a third set of two consecutive bits may be used to determine a phase rotation for a third resource element in the set of resource elements, shown as RE3.
  • the third value of 10 may correspond to a third phase rotation of j, and the UE 120 may apply this third phase rotation to the third resource element.
  • a fourth set of two consecutive bits, shown as 11, may be used to determine a phase rotation for a fourth resource element in the set of resource elements, shown as RE4.
  • the fourth value of 11 may correspond to a fourth phase rotation of -j, and the UE 120 may apply this fourth phase rotation to the fourth resource element.
  • the UE 120 may rotate a respective phase of each resource element, in the set of resource elements, in a similar manner.
  • a length of the random binary sequence (e.g., a number of bits) may depend on a number of resource elements in which the DMRS is transmitted.
  • the UE 120 uses a set of two consecutive bits to determine a phase rotation for a resource element corresponding to the set of two consecutive bits (e.g., for quadrate phase shift keying (QPSK) modulation) .
  • QPSK quadrate phase shift keying
  • phase rotations may be indicated using two bits.
  • a different number of bits may be used to determine a phase rotation for a resource element, such as 1 bit (e.g., for binary phase shift keying (BPSK) , to represent two possible phase rotations) , 3 bits (e.g., for 8-PSK, to represent 8 possible phase rotations) , 4 bits (e.g., for 16-quadrature amplitude modulation (16-PSK) , to represent 16 possible phase rotations) , and/or the like.
  • the set of bits corresponding to a resource element may be non-consecutive.
  • the base station 110 may receive the DMRS, and may communicate with the UE 120 based at least in part on the DMRS, as described above in connection with Fig. 4.
  • different UEs that transmit DMRS and/or NOMA communications over the same frequency and time resources may use a same root DMRS sequence (e.g., indicated by the base station 110) .
  • the base station 110 may be capable of differentiating between DMRS from different UEs 120.
  • a likelihood of DMRS collisions may be reduced, thereby improving CSI estimation at the base station 110 and improving network performance.
  • a number of available DMRS sequences may be increased via RE phase rotation, thereby reducing the likelihood of DMRS collision.
  • degradations to cross-correlation performance and/or peak-to-average-power ratio (PAPR) performance may be mitigated by selecting RE rotation patterns that have good cross-correlation performance and/or by reducing (e.g., minimizing) a phase shift between consecutive REs in association with root sequences.
  • PAPR peak-to-average-power ratio
  • the seeds to be included in the pool of random seeds may be selected and/or configured such that those seeds result in generation of respective binary sequences that leads to RE rotation patterns with good cross-correlation performance, and/or such that those seeds result in generation of respective binary sequences that reduce or minimize a phase shift between consecutive REs with respect to a root DMRS sequence.
  • Fig. 5 is provided as an example. Other examples are possible and may differ from what was described with respect to Fig. 5.
  • Fig. 6 is a diagram illustrating another example 600 of DMRS generation in grant-free uplink NOMA systems, in accordance with various aspects of the present disclosure.
  • a base station 110 may broadcast information for obtaining a pool of parameters associated with generating and/or transmitting DMRS for grant-free uplink NOMA communications, as described above in connection with Figs. 4-5.
  • a UE 120 may determine the pool of parameters, as described above in connection with Figs. 4-5. In some aspects, the UE 120 may determine the pool of parameters based at least in part on the information broadcast by the base station 110.
  • the pool of parameters may include a pool of scrambling identifiers.
  • the UE 120 may randomly select a scrambling identifier from the pool of scrambling identifiers.
  • the pool of scrambling identifiers may be cell-specific, and different cells may be associated with different pools of scrambling identifiers, thereby reducing a likelihood of inter-cell interference for DMRS transmissions.
  • the UE 120 may randomly select a scrambling identifier when transform precoding is disabled for the UE 120.
  • the UE 120 may randomly select a ZC group identifier and/or cyclic shift value, as described in more detail in connection with Fig. 7.
  • the pool of parameters used by the UE 120 to generate and/or transmit the DMRS may depend on a configuration of the UE 120.
  • the base station 110 may broadcast information that can be used to obtain multiple pools of parameters, and the UE 120 may select a pool of parameters based at least in part on the configuration of the UE 120.
  • the UE 120 may generate a random binary sequence c (n) using the randomly selected scrambling identifier.
  • the UE 120 may generate the random binary sequence based at least in part on the randomly selected scrambling identifier and a subframe index of a subframe in which the DMRS is to be transmitted.
  • the UE 120 may generate an initial binary sequence c init as follows, where represents a value of the random scrambling identifier, and where N represents the subframe index of the subframe in which the DMRS is to be transmitted:
  • the UE 120 may then generate the random binary sequence c (n) (e.g., a generic pseudo-random sequence) using the initial binary sequence c init and a Gold sequence (e.g., a length-31 Gold sequence) , such as by using c init as input to generate a pseudo-random sequence according to a telecommunication standard (e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like) .
  • a telecommunication standard e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like
  • the UE 120 may generate a DMRS (e.g., a single DMRS or multiple DMRS) based at least in part on the random binary sequence c (n) .
  • a DMRS e.g., a single DMRS or multiple DMRS
  • the UE 120 may generate the DMRS as follows, where a real part and/or an imaginary part of a resource element, in which the DMRS is to be transmitted, are determined based at least in part on the random binary sequence c (n) :
  • the UE 120 may transmit the DMRS in a set of resource elements, and the UE 120 may determine a real part and/or imaginary part of one or more of those resources elements (e.g., at least one resource element in the set, multiple resource elements in the set, or all resource elements in the set) based at least in part on the random binary sequence.
  • a set of bits e.g., a set of consecutive bits included in the random binary sequence may correspond to a resource element in the set of resource elements, and the value (s) of the set of bits may be used by the UE 120 to determine the real part and/or the imaginary part of the resource element.
  • a set of two consecutive bits may correspond to a resource element, and a value of the two consecutive bits may be used to determine the real part and/or the imaginary part of the resource element.
  • different bit values may correspond to different values for the real part and/or the imaginary part.
  • the UE 120 may determine a respective real part and/or imaginary part of each resource element, in the set of resource elements in which the DMRS is to be transmitted, using a respective set of consecutive bits.
  • a different number of bits e.g., other than two
  • the set of bits corresponding to a resource element may be non-consecutive.
  • the UE 120 may generate and/or transmit the DMRS based at least in part on the random binary sequence. For example, the UE 120 may generate the DMRS as described above, where a real and imaginary part of resource elements in which the DMRS is to be transmitted depend on the random binary sequence. The UE 120 may then transmit the DMRS, to the base station 110, in the resource elements.
  • the base station 110 may receive the DMRS, and may communicate with the UE 120 based at least in part on the DMRS, as described above in connection with Figs. 4-5.
  • different UEs that transmit DMRS and/or NOMA communications over the same frequency and time resources may use different root DMRS sequences (e.g., generated using different random binary sequences) because the UEs 120 use randomly selected scrambling identifiers rather than all using a same scrambling identifier indicated by the base station 110.
  • the base station 110 may be capable of differentiating between DMRS from different UEs 120, and a likelihood of DMRS collisions may be reduced, thereby improving CSI estimation at the base station 110 and improving network performance.
  • Fig. 6 is provided as an example. Other examples are possible and may differ from what was described with respect to Fig. 6.
  • Fig. 7 is a diagram illustrating another example 700 of DMRS generation in grant-free uplink NOMA systems, in accordance with various aspects of the present disclosure.
  • a base station 110 may broadcast information for obtaining one or more pools of parameters associated with generating and/or transmitting DMRS for grant-free uplink NOMA communications, in a similar manner as described above in connection with Figs. 4-6.
  • a UE 120 may determine the one or more pools of parameters, in a similar manner as described above in connection with Figs. 4-6. In some aspects, the UE 120 may determine the one or more pools of parameters based at least in part on the information broadcast by the base station 110.
  • the one or more pools of parameters may include a first pool of Zadoff-Chu (ZC) group identifiers and/or a second pool of cyclic shift values.
  • the one or more pools of parameters may include only the first pool of ZC group identifiers, and the UE 120 may determine a preconfigured cyclic shift value (e.g., indicated by the base station 110) .
  • the one or more pools of parameters may include only the second pool of cyclic shift values, and the UE 120 may determine a preconfigured ZC group identifier (e.g., indicated by the base station 110) .
  • the one or more pools may include both the first pool and the second pool, thereby increasing randomization and an available number of random DMRS sequences.
  • the UE 120 may randomly select a ZC group identifier from the first pool, and/or may randomly select a cyclic shift value from the second pool.
  • the first pool and/or the second pool may be cell-specific, and different cells may be associated with different pools of ZC group identifiers and/or different pools of cyclic shift values, thereby reducing a likelihood of inter-cell interference for DMRS transmissions.
  • different ZC group identifiers, in the first pool may be associated with different pools of cyclic shift values, which may reduce interference (e.g., inter-cell interference and/or the like) .
  • a first ZC group identifier may be associated with a first sub-pool of cyclic shift values
  • a second ZC group identifier may be associated with a second sub-pool of cyclic shift values
  • the first sub-pool of cyclic shift values and the second sub-pool of cyclic shift values may be mutually exclusive, or may partially overlap.
  • the UE 120 may randomly select a ZC group identifier and/or cyclic shift value when transform precoding is enabled for the UE 120.
  • the UE 120 may randomly select a scrambling identifier, as described above in connection with Fig. 6.
  • the pool of parameters used by the UE 120 to generate and/or transmit the DMRS may depend on a configuration of the UE 120.
  • the base station 110 may broadcast information that can be used to obtain multiple pools of parameters, and the UE 120 may select a pool of parameters based at least in part on the configuration of the UE 120.
  • the UE 120 may generate a random Zadoff-Chu (ZC) sequence using the randomly selected ZC group identifier and/or the randomly selected cyclic shift value.
  • ZC Zadoff-Chu
  • the UE 120 may generate the random ZC sequence based at least in part on a subframe index of a subframe in which the DMRS is to be transmitted and at least one of the randomly selected ZC group identifier or the randomly selected cyclic shift value.
  • UE 120 may use the subframe index the randomly selected ZC group identifier, and the randomly selected cyclic shift value to generate the ZC sequence, and may use the generated ZC sequence to generate the DMRS, such as according to a telecommunication standard (e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like) .
  • a telecommunication standard e.g., a 3GPP standard, such as 3GPP TS 38.211 and/or the like.
  • the UE 120 may generate and/or transmit the DMRS based at least in part on the random ZC sequence. For example, the UE 120 may generate the DMRS as described above, where the DMRS is generated using a random ZC sequence. The UE 120 may then transmit the DMRS, to the base station 110, in a set of resource elements.
  • the base station 110 may receive the DMRS, and may communicate with the UE 120 based at least in part on the DMRS, as described above in connection with Figs. 4-6.
  • different UEs that transmit DMRS and/or NOMA communications over the same frequency and time resources may use different root ZC sequences and/or different cyclic shifted versions of a same ZC sequence to generate respective DMRS because the UEs 120 use randomly selected ZC group identifiers and/or cyclic shift values rather than all using a same ZC group identifier and/or cyclic shift value indicated by the base station 110.
  • the base station 110 may be capable of differentiating between DMRS from different UEs 120, and a likelihood of DMRS collisions may be reduced, thereby improving CSI estimation at the base station 110 and improving network performance.
  • Fig. 7 is provided as an example. Other examples are possible and may differ from what was described with respect to Fig. 7.
  • Fig. 8 is a diagram illustrating an example process 800 performed, for example, by a UE, in accordance with various aspects of the present disclosure.
  • Example process 800 is an example where a UE (e.g., UE 120 and/or the like) performs operations associated with DMRS generation in grant-free uplink NOMA systems.
  • a UE e.g., UE 120 and/or the like
  • process 800 may include generating a random binary sequence associated with transmission of a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission (block 810) .
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • the UE e.g., using controller/processor 280 and/or the like
  • process 800 may include transmitting the DMRS in a set of resource elements, wherein a phase of at least one resource element, in the set of resource elements, is rotated based at least in part on the random binary sequence (block 820) .
  • the UE e.g., using controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, and/or the like
  • Process 800 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.
  • the random binary sequence is generated based at least in part on a random seed and a subframe index of a subframe in which the DMRS is to be transmitted.
  • the random seed is randomly selected from a pool of seeds.
  • the pool of seeds is determined by the UE based at least in part on information broadcast by a base station.
  • the pool of seeds is cell-specific.
  • different cells are associated with different pools of seeds.
  • a respective phase of each resource element, in the set of resource elements is rotated based at least in part on the random binary sequence.
  • each set of at least two consecutive bits in the random binary sequence indicates a phase rotation for a corresponding resource element in the set of resource elements.
  • different UEs transmitting NOMA communications over the same frequency and time resources use a same root DMRS sequence prior to rotating the phase of the at least one resource element.
  • process 800 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 8. Additionally, or alternatively, two or more of the blocks of process 800 may be performed in parallel.
  • Fig. 9 is a diagram illustrating an example process 900 performed, for example, by a UE, in accordance with various aspects of the present disclosure.
  • Example process 900 is an example where a UE (e.g., UE 120 and/or the like) performs operations associated with DMRS generation in grant-free uplink NOMA systems.
  • a UE e.g., UE 120 and/or the like
  • process 900 may include generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values (block 910) .
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • the UE may generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating a DMRS for a grant-free uplink NOMA transmission, as described above in connection with Figs. 4-7.
  • the pool of parameters includes at least one of: a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values.
  • process 900 may include generating the DMRS based at least in part on the random sequence (block 920) .
  • the UE e.g., using controller/processor 280 and/or the like
  • process 900 may include transmitting the DMRS in a set of resource elements (block 930) .
  • the UE e.g., using controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, and/or the like
  • Process 900 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.
  • the pool of parameters includes the pool of scrambling identifiers, and the randomly selected parameter is a randomly selected scrambling identifier.
  • the random sequence is a random binary sequence generated based at least in part on the random scrambling identifier and a subframe index of a subframe in which the DMRS is to be transmitted.
  • a real part and an imaginary part of at least one resource element, in the set of resource elements are determined based at least in part on the random sequence. In some aspects, a real part and an imaginary part of each resource element, in the set of resource elements, are determined based at least in part on the random sequence. In some aspects, each set of two consecutive bits in the random sequence is used to determine a real part and an imaginary part for a corresponding resource element in the set of resource elements. In some aspects, different UEs transmitting NOMA communications over the same frequency and time resources use different root DMRS sequences generated using different random sequences.
  • the pool of parameters includes at least one of the pool of Zadoff-Chu group identifiers or the pool of cyclic shift values
  • the randomly selected parameter includes at least one of a randomly selected Zadoff-Chu group identifier or a randomly selected cyclic shift value.
  • the random sequence is a random Zadoff-Chu sequence generated based at least in part on a subframe index of a subframe in which the DMRS is to be transmitted and at least one of the randomly selected Zadoff-Chu group identifier or the randomly selected cyclic shift value.
  • different Zadoff-Chu group identifiers in the pool of Zadoff-Chu group identifiers, are associated with different pools of cyclic shift values.
  • different UEs use different root Zadoff-Chu sequences or different cyclic shifted versions of a same Zadoff-Chu sequence to generate respective DMRS.
  • the pool of parameters is determined by the UE based at least in part on information broadcast a base station.
  • process 900 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 9. Additionally, or alternatively, two or more of the blocks of process 900 may be performed in parallel.
  • Fig. 10 is a diagram illustrating an example process 1000 performed, for example, by a UE, in accordance with various aspects of the present disclosure.
  • Example process 1000 is an example where a UE (e.g., UE 120 and/or the like) performs operations associated with DMRS generation in grant-free uplink NOMA systems.
  • a UE e.g., UE 120 and/or the like
  • process 1000 may include generating a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a demodulation reference signal (DMRS) for a grant-free uplink non-orthogonal multiple access (NOMA) transmission, wherein the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values (block 1010) .
  • DMRS demodulation reference signal
  • NOMA grant-free uplink non-orthogonal multiple access
  • the UE may generate a random sequence using a randomly selected parameter selected from a pool of parameters associated with generating or transmitting a DMRS for a grant-free uplink NOMA transmission, as described above in connection with Figs. 4-7.
  • the pool of parameters includes at least one of: a pool of seeds to be used for resource element phase rotation, a pool of scrambling identifiers, a pool of Zadoff-Chu group identifiers, or a pool of cyclic shift values.
  • process 1000 may include generating or transmitting the DMRS based at least in part on the random sequence (block 1020) .
  • the UE e.g., using controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, and/or the like
  • Process 1000 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.
  • the random sequence includes at least one of: a random binary sequence generated based at least in part on a seed randomly selected from the pool of seeds or a scrambling identifier randomly selected from the pool of scrambling identifiers, or a random Zadoff-Chu sequence generated based at least in part on a Zadoff-Chu group identifier randomly selected from the pool of Zadoff-Chu group identifiers or a cyclic shift value randomly selected from the pool of cyclic shift values.
  • the pool of parameters is determined by the UE based at least in part on information broadcast a base station.
  • process 1000 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 10. Additionally, or alternatively, two or more of the blocks of process 1000 may be performed in parallel.
  • the term component is intended to be broadly construed as hardware, firmware, or a combination of hardware and software.
  • a processor is implemented in hardware, firmware, or a combination of hardware and software.
  • satisfying a threshold may refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.
  • “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Divers aspects de la présente invention concernent de manière générale la communication sans fil. Selon certains aspects, un équipement utilisateur peut : générer une séquence aléatoire à l'aide d'un paramètre sélectionné de manière aléatoire à partir d'un pool de paramètres associés à la génération ou à la transmission d'un signal de référence de démodulation (DMRS) pour une transmission à accès multiple non orthogonal (NOMA) de liaison montante sans autorisation, le pool de paramètres comprenant au moins l'un parmi : un pool de germes devant être utilisés pour une rotation en phase d'un élément de ressource, un pool d'identifiants d'embrouillage, un pool d'identifiants de groupe de Zadoff-Chu, ou un pool de valeurs de décalage cyclique ; et générer ou transmettre le DMRS sur la base, au moins en partie, de la séquence aléatoire. L'invention se présente également sous de nombreux autres aspects.
PCT/CN2018/098531 2018-08-03 2018-08-03 Génération de signal de référence de démodulation dans des systèmes d'accès multiple non orthogonal de liaison montante sans autorisation WO2020024262A1 (fr)

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Cited By (1)

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US20220416993A1 (en) * 2021-06-23 2022-12-29 Qualcomm Incorporated Demodulator configuration based on user equipment signaling

Citations (3)

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Publication number Priority date Publication date Assignee Title
CN102413572A (zh) * 2011-09-28 2012-04-11 中兴通讯股份有限公司 Dmrs及其信令的发送方法及装置
US20160219624A1 (en) * 2015-01-23 2016-07-28 Mediatek Inc. LTE RACH Procedure Enhancement
WO2018030764A1 (fr) * 2016-08-09 2018-02-15 Samsung Electronics Co., Ltd. Appareil et procédé de retransmission dans un système de communications sans fil

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102413572A (zh) * 2011-09-28 2012-04-11 中兴通讯股份有限公司 Dmrs及其信令的发送方法及装置
US20160219624A1 (en) * 2015-01-23 2016-07-28 Mediatek Inc. LTE RACH Procedure Enhancement
WO2018030764A1 (fr) * 2016-08-09 2018-02-15 Samsung Electronics Co., Ltd. Appareil et procédé de retransmission dans un système de communications sans fil

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220416993A1 (en) * 2021-06-23 2022-12-29 Qualcomm Incorporated Demodulator configuration based on user equipment signaling
US11997185B2 (en) * 2021-06-23 2024-05-28 Qualcomm Incorporated Demodulator configuration based on user equipment signaling

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