WO2020032530A1 - Method of transmitting uplink signals, and device therefor - Google Patents

Method of transmitting uplink signals, and device therefor Download PDF

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Publication number
WO2020032530A1
WO2020032530A1 PCT/KR2019/009779 KR2019009779W WO2020032530A1 WO 2020032530 A1 WO2020032530 A1 WO 2020032530A1 KR 2019009779 W KR2019009779 W KR 2019009779W WO 2020032530 A1 WO2020032530 A1 WO 2020032530A1
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WO
WIPO (PCT)
Prior art keywords
configured grant
random access
transmission
access procedure
harq process
Prior art date
Application number
PCT/KR2019/009779
Other languages
French (fr)
Inventor
Jeonggu LEE
Sunyoung Lee
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Lg Electronics Inc.
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Publication date
Application filed by Lg Electronics Inc. filed Critical Lg Electronics Inc.
Publication of WO2020032530A1 publication Critical patent/WO2020032530A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/1874—Buffer management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/188—Time-out mechanisms
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/1887—Scheduling and prioritising arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access

Definitions

  • the present invention relates to a wireless communication system.
  • Various types of signals including data signals and control signals, are communicated via the UL and DL. Scheduling of such communications is typically performed, to achieve improved efficiency, latency, and/or reliability. Overcoming delay or latency has become an important challenge in applications whose performance critically depends on delay/latency.
  • a method for transmitting uplink signals by a user equipment in a wireless communication system comprises: determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure; skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and performing the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process.
  • HARQ hybrid automatic retransmission request
  • a device for a user equipment of transmitting uplink signals in a wireless communication system comprises: at least one processor; and at least one computer memory that is operably connectable to the at least one processor and that has stored thereon instructions which, when executed, cause the at least one processor to perform operations.
  • the operations comprises: determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure; skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and performing, via a transceiver of the user equipment, the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process.
  • HARQ hybrid automatic retransmission request
  • the method or operations may further comprise: starting a configured grant timer for the HARQ process when transmitting a random access preamble (Msg1) of the random access procedure.
  • Msg1 random access preamble
  • skipping the uplink transmission on the first configured grant may comprise: generating no MAC PDU for the first configured grant.
  • skipping the uplink transmission on the first configured grant may comprise: skipping transmitting a MAC PDU stored in a HARQ buffer of the HARQ process associated with the first configured grant.
  • the method or operations may further comprise: performing, via the transceiver of the user equipment, uplink transmission on a second configured grant.
  • the second configured grant may occur while the random access procedure is not on-going.
  • skipping the uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process may comprise: skipping the uplink transmission on the first configured grant irrespective of whether a configured grant timer for the HARQ process is running.
  • the first configured grant may comprise a configured grant occurring after transmission of a random access preamble of the random access procedure and before completion of the random access procedure.
  • the user equipment is an autonomous vehicle that communicates with at least a mobile terminal, a network, and another autonomous vehicle other than the user equipment.
  • implementations of the present disclosure may provide one or more of the following advantages.
  • radio communication signals can be more efficiently transmitted and/or received. Therefore, overall throughput of a radio communication system can be improved.
  • delay/latency occurring during communication between a user equipment and a BS may be reduced.
  • signals in a new radio access technology system can be transmitted and/or received more effectively.
  • transmission via a configured grant can have enough retransmission opportunities even when the transmission occurs during a random access procedure.
  • a random access procedure can be performed without being interrupted by a configured grant throughout the whole random access procedure.
  • FIG. 1 illustrates an example of a communication system 1 to which implementations of the present disclosure is applied;
  • FIG. 2 is a block diagram illustrating examples of communication devices which can perform a method according to the present disclosure
  • FIG. 3 illustrates another example of a wireless device which can perform implementations of the present invention
  • FIG. 4 illustrates an example of protocol stacks in a third generation partnership project (3GPP) based wireless communication system
  • FIG. 5 illustrates an example of a frame structure in a 3GPP based wireless communication system
  • FIG. 6 illustrates a data flow example in the 3GPP new radio (NR) system
  • FIG. 7 illustrates an example showing a case where UE cannot perform retransmission for PDU via a configured grant during the random access procedure
  • FIG. 8 illustrates an example of a flow diagram for UL transmission according to an implementation of the present disclosure
  • FIG. 9 illustrates examples of UL transmission on a configured grant considering a random access procedure according to the implementations of the present disclosure.
  • FIG. 10 illustrates an example of UL transmission on a configured grant considering a random access procedure and a timer according to an implementation of the present disclosure.
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • MC-FDMA multicarrier frequency division multiple access
  • CDMA may be embodied through radio technology such as universal terrestrial radio access (UTRA) or CDMA2000.
  • TDMA may be embodied through radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE).
  • GSM global system for mobile communications
  • GPRS general packet radio service
  • EDGE enhanced data rates for GSM evolution
  • OFDMA may be embodied through radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA).
  • IEEE institute of electrical and electronics engineers
  • Wi-Fi Wi-Fi
  • WiMAX IEEE 802.16
  • E-UTRA evolved UTRA
  • UTRA is a part of a universal mobile telecommunications system (UMTS).
  • 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA.
  • 3GPP LTE employs OFDMA in DL and SC-FDMA in UL.
  • LTE-advanced (LTE-A) is an evolved version of 3GPP LTE.
  • implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system.
  • the technical features of the present disclosure are not limited thereto.
  • the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.
  • UE User Equipment
  • PDCP Packet Data Convergence Protocol
  • RRC Radio Resource Control
  • 3GPP NR e.g. 5G
  • UE User Equipment
  • PDCP Packet Data Convergence Protocol
  • RRC Radio Resource Control
  • SDAP Service Data Adaptation Protocol
  • a user equipment may be a fixed or mobile device.
  • the UE include various devices that transmit and receive user data and/or various kinds of control information to and from a base station (BS).
  • a BS generally refers to a fixed station that performs communication with a UE and/or another BS, and exchanges various kinds of data and control information with the UE and another BS.
  • the BS may be referred to as an advanced base station (ABS), a node-B (NB), an evolved node-B (eNB), a base transceiver system (BTS), an access point (AP), a processing server (PS), etc.
  • ABS advanced base station
  • NB node-B
  • eNB evolved node-B
  • BTS base transceiver system
  • AP access point
  • PS processing server
  • a BS of the UMTS is referred to as a NB
  • a BS of the enhanced packet core (EPC) / long term evolution (LTE) system is referred to as an eNB
  • a BS of the new radio (NR) system is referred to as a gNB.
  • a node refers to a point capable of transmitting/receiving a radio signal through communication with a UE.
  • Various types of BSs may be used as nodes irrespective of the terms thereof.
  • a BS, a node B (NB), an e-node B (eNB), a pico-cell eNB (PeNB), a home eNB (HeNB), a relay, a repeater, etc. may be a node.
  • the node may not be a BS.
  • the node may be a radio remote head (RRH) or a radio remote unit (RRU).
  • the RRH or RRU generally has a lower power level than a power level of a BS.
  • RRH/RRU Since the RRH or RRU (hereinafter, RRH/RRU) is generally connected to the BS through a dedicated line such as an optical cable, cooperative communication between RRH/RRU and the BS can be smoothly performed in comparison with cooperative communication between BSs connected by a radio line.
  • At least one antenna is installed per node.
  • the antenna may include a physical antenna or an antenna port or a virtual antenna.
  • the term "cell” may refer to a geographic area to which one or more nodes provide a communication system, or refer to radio resources.
  • a “cell” of a geographic area may be understood as coverage within which a node can provide service using a carrier and a "cell” as radio resources (e.g. time-frequency resources) is associated with bandwidth (BW) which is a frequency range configured by the carrier.
  • the "cell” associated with the radio resources is defined by a combination of downlink resources and uplink resources, for example, a combination of a downlink (DL) component carrier (CC) and an uplink (UL) CC.
  • the cell may be configured by downlink resources only, or may be configured by downlink resources and uplink resources.
  • the coverage of the node may be associated with coverage of the "cell" of radio resources used by the node. Accordingly, the term "cell" may be used to represent service coverage of the node sometimes, radio resources at other times, or a range that signals using the radio resources can reach with valid strength at other times.
  • a physical downlink control channel (PDCCH), and a physical downlink shared channel (PDSCH) refer to a set of time-frequency resources or resource elements (REs) carrying downlink control information (DCI), and a set of time-frequency resources or REs carrying downlink data, respectively.
  • a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH) and a physical random access channel (PRACH) refer to a set of time-frequency resources or REs carrying uplink control information (UCI), a set of time-frequency resources or REs carrying uplink data and a set of time-frequency resources or REs carrying random access signals, respectively.
  • CA carrier aggregation
  • a UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities.
  • CA is supported for both contiguous and non-contiguous CCs.
  • RRC radio resource control
  • one serving cell provides the non-access stratum (NAS) mobility information
  • NAS non-access stratum
  • RRC connection re-establishment/handover one serving cell provides the security input.
  • This cell is referred to as the Primary Cell (PCell).
  • the PCell is a cell, operating on the primary frequency, in which the UE either performs the initial connection establishment procedure or initiates the connection re-establishment procedure.
  • SCells can be configured to form together with the PCell a set of serving cells.
  • An SCell is a cell providing additional radio resources on top of Special Cell.
  • the configured set of serving cells for a UE therefore always consists of one PCell and one or more SCells.
  • special Cell refers to the PCell of the master cell group (MCG) or the PSCell of the secondary cell group (SCG), and otherwise the term Special Cell refers to the PCell.
  • MCG master cell group
  • SCG secondary cell group
  • An SpCell supports physical uplink control channel (PUCCH) transmission and contention-based random access, and is always activated.
  • PUCCH physical uplink control channel
  • the MCG is a group of serving cells associated with a master node, comprising of the SpCell (PCell) and optionally one or more SCells.
  • the SCG is the subset of serving cells associated with a secondary node, comprising of the PSCell and zero or more SCells, for a UE configured with DC.
  • serving cells is used to denote the set of cells comprising of the SpCell(s) and all SCells.
  • the MCG is a group of serving cells associated with a master BS which terminates at least S1-MME
  • the SCG is a group of serving cells associated with a secondary BS that is providing additional radio resources for the UE but is not the master BS.
  • the SCG includes a primary SCell (PSCell) and optionally one or more SCells.
  • PSCell primary SCell
  • two MAC entities are configured in the UE: one for the MCG and one for the SCG.
  • Each MAC entity is configured by RRC with a serving cell supporting PUCCH transmission and contention based Random Access.
  • the term SpCell refers to such cell
  • SCell refers to other serving cells.
  • the term SpCell either refers to the PCell of the MCG or the PSCell of the SCG depending on if the MAC entity is associated to the MCG or the SCG, respectively.
  • monitoring a channel refers to attempting to decode the channel.
  • monitoring a physical downlink control channel refers to attempting to decode PDCCH(s) (or PDCCH candidates).
  • C-RNTI refers to a cell RNTI
  • SI-RNTI refers to a system information RNTI
  • P-RNTI refers to a paging RNTI
  • RA-RNTI refers to a random access RNTI
  • SC-RNTI refers to a single cell RNTI
  • SPS C-RNTI refers to a semi-persistent scheduling C-RNTI
  • CS-RNTI refers to a configured scheduling RNTI.
  • FIG. 1 illustrates an example of a communication system 1 to which implementations of the present disclosure is applied.
  • Three main requirement categories for 5G include (1) a category of enhanced mobile broadband (eMBB), (2) a category of massive machine type communication (mMTC), and (3) a category of ultra-reliable and low latency communications (URLLC).
  • eMBB enhanced mobile broadband
  • mMTC massive machine type communication
  • URLLC ultra-reliable and low latency communications
  • Partial use cases may require a plurality of categories for optimization and other use cases may focus only upon one key performance indicator (KPI).
  • KPI key performance indicator
  • eMBB far surpasses basic mobile Internet access and covers abundant bidirectional work and media and entertainment applications in cloud and augmented reality.
  • Data is one of 5G core motive forces and, in a 5G era, a dedicated voice service may not be provided for the first time.
  • voice will be simply processed as an application program using data connection provided by a communication system.
  • Main causes for increased traffic volume are due to an increase in the size of content and an increase in the number of applications requiring high data transmission rate.
  • a streaming service (of audio and video), conversational video, and mobile Internet access will be more widely used as more devices are connected to the Internet.
  • Cloud storage and applications are rapidly increasing in a mobile communication platform and may be applied to both work and entertainment.
  • the cloud storage is a special use case which accelerates growth of uplink data transmission rate.
  • 5G is also used for remote work of cloud. When a tactile interface is used, 5G demands much lower end-to-end latency to maintain user good experience.
  • Entertainment for example, cloud gaming and video streaming, is another core element which increases demand for mobile broadband capability. Entertainment is essential for a smartphone and a tablet in any place including high mobility environments such as a train, a vehicle, and an airplane.
  • Other use cases are augmented reality for entertainment and information search. In this case, the augmented reality requires very low latency and instantaneous data volume.
  • one of the most expected 5G use cases relates a function capable of smoothly connecting embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential IoT devices will reach 204 hundred million up to the year of 2020.
  • An industrial IoT is one of categories of performing a main role enabling a smart city, asset tracking, smart utility, agriculture, and security infrastructure through 5G.
  • URLLC includes a new service that will change industry through remote control of main infrastructure and an ultra-reliable/available low-latency link such as a self-driving vehicle.
  • a level of reliability and latency is essential to control a smart grid, automatize industry, achieve robotics, and control and adjust a drone.
  • 5G is a means of providing streaming evaluated as a few hundred megabits per second to gigabits per second and may complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such fast speed is needed to deliver TV in resolution of 4K or more (6K, 8K, and more), as well as virtual reality and augmented reality.
  • Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games.
  • a specific application program may require a special network configuration. For example, for VR games, gaming companies need to incorporate a core server into an edge network server of a network operator in order to minimize latency.
  • Automotive is expected to be a new important motivated force in 5G together with many use cases for mobile communication for vehicles. For example, entertainment for passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect connection of high quality regardless of their locations and speeds.
  • Another use case of an automotive field is an AR dashboard.
  • the AR dashboard causes a driver to identify an object in the dark in addition to an object seen from a front window and displays a distance from the object and a movement of the object by overlapping information talking to the driver.
  • a wireless module enables communication between vehicles, information exchange between a vehicle and supporting infrastructure, and information exchange between a vehicle and other connected devices (e.g., devices accompanied by a pedestrian).
  • a safety system guides alternative courses of a behavior so that a driver may drive more safely drive, thereby lowering the danger of an accident.
  • the next stage will be a remotely controlled or self-driven vehicle. This requires very high reliability and very fast communication between different self-driven vehicles and between a vehicle and infrastructure. In the future, a self-driven vehicle will perform all driving activities and a driver will focus only upon abnormal traffic that the vehicle cannot identify.
  • Technical requirements of a self-driven vehicle demand ultra-low latency and ultra-high reliability so that traffic safety is increased to a level that cannot be achieved by human being.
  • a smart city and a smart home/building mentioned as a smart society will be embedded in a high-density wireless sensor network.
  • a distributed network of an intelligent sensor will identify conditions for costs and energy-efficient maintenance of a city or a home. Similar configurations may be performed for respective households. All of temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, real-time HD video may be demanded by a specific type of device to perform monitoring.
  • the smart grid collects information and connects the sensors to each other using digital information and communication technology so as to act according to the collected information. Since this information may include behaviors of a supply company and a consumer, the smart grid may improve distribution of fuels such as electricity by a method having efficiency, reliability, economic feasibility, production sustainability, and automation.
  • the smart grid may also be regarded as another sensor network having low latency.
  • Mission critical application is one of 5G use scenarios.
  • a health part contains many application programs capable of enjoying benefit of mobile communication.
  • a communication system may support remote treatment that provides clinical treatment in a faraway place. Remote treatment may aid in reducing a barrier against distance and improve access to medical services that cannot be continuously available in a faraway rural area. Remote treatment is also used to perform important treatment and save lives in an emergency situation.
  • the wireless sensor network based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.
  • Wireless and mobile communication gradually becomes important in the field of an industrial application.
  • Wiring is high in installation and maintenance cost. Therefore, a possibility of replacing a cable with reconstructible wireless links is an attractive opportunity in many industrial fields.
  • it is necessary for wireless connection to be established with latency, reliability, and capacity similar to those of the cable and management of wireless connection needs to be simplified. Low latency and a very low error probability are new requirements when connection to 5G is needed.
  • Logistics and freight tracking are important use cases for mobile communication that enables inventory and package tracking anywhere using a location-based information system.
  • the use cases of logistics and freight typically demand low data rate but require location information with a wide range and reliability.
  • the communication system 1 includes wireless devices, base stations (BSs), and a network.
  • FIG. 1 illustrates a 5G network as an example of the network of the communication system 1, the implementations of the present disclosure are not limited to the 5G system, and can be applied to the future communication system beyond the 5G system.
  • the BSs and the network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS/network node with respect to other wireless devices.
  • the wireless devices represent devices performing communication using radio access technology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE)) and may be referred to as communication/radio/5G devices.
  • RAT radio access technology
  • the wireless devices may include, without being limited to, a robot 100a, vehicles 100b-1 and 100b-2, an eXtended Reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an Artificial Intelligence (AI) device/server 400.
  • the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles.
  • the vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone).
  • UAV Unmanned Aerial Vehicle
  • the XR device may include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) device and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc.
  • the hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook).
  • the home appliance may include a TV, a refrigerator, and a washing machine.
  • the IoT device may include a sensor and a smartmeter.
  • the wireless devices 100a to 100f may be called user equipments (UEs).
  • a user equipment (UE) may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an unmanned aerial vehicle (UAV), an artificial intelligence (AI) module, a robot, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or a financial device), a security device, a weather/environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field.
  • PDA personal digital assistant
  • PMP portable multimedia player
  • PC
  • the unmanned aerial vehicle may be, for example, an aircraft aviated by a wireless control signal without a human being onboard.
  • the VR device may include, for example, a device for implementing an object or a background of the virtual world.
  • the AR device may include, for example, a device implemented by connecting an object or a background of the virtual world to an object or a background of the real world.
  • the MR device may include, for example, a device implemented by merging an object or a background of the virtual world into an object or a background of the real world.
  • the hologram device may include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information, using an interference phenomenon of light generated when two laser lights called holography meet.
  • the public safety device may include, for example, an image relay device or an image device that is wearable on the body of a user.
  • the MTC device and the IoT device may be, for example, devices that do not require direct human intervention or manipulation.
  • the MTC device and the IoT device may include smartmeters, vending machines, thermometers, smartbulbs, door locks, or various sensors.
  • the medical device may be, for example, a device used for the purpose of diagnosing, treating, relieving, curing, or preventing disease.
  • the medical device may be a device used for the purpose of diagnosing, treating, relieving, or correcting injury or impairment.
  • the medical device may be a device used for the purpose of inspecting, replacing, or modifying a structure or a function.
  • the medical device may be a device used for the purpose of adjusting pregnancy.
  • the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for procedure.
  • the security device may be, for example, a device installed to prevent a danger that may arise and to maintain safety.
  • the security device may be a camera, a CCTV, a recorder, or a black box.
  • the FinTech device may be, for example, a device capable of providing a financial service such as mobile payment.
  • the FinTech device may include a payment device or a point of sales (POS) system.
  • the weather/environment device may include, for example, a device for monitoring or predicting a weather/environment.
  • the wireless devices 100a to 100f may be connected to the network 300 via the BSs 200.
  • An AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300.
  • the network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network.
  • the wireless devices 100a to 100f may communicate with each other through the BSs 200/network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs/network.
  • the vehicles 100b-1 and 100b-2 may perform direct communication (e.g.
  • V2V Vehicle-to-Vehicle
  • V2X Vehicle-to-everything
  • Wireless communication/connections 150a and 150b may be established between the wireless devices 100a to 100f/BS 200-BS 200.
  • the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as uplink/downlink communication 150a and sidelink communication 150b (or D2D communication).
  • the wireless devices and the BSs/the wireless devices may transmit/receive radio signals to/from each other through the wireless communication/connections 150a and 150b.
  • the wireless communication/connections 150a and 150b may transmit/receive signals through various physical channels.
  • various configuration information configuring processes various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.
  • various signal processing processes e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping
  • resource allocating processes for transmitting/receiving radio signals
  • FIG. 2 is a block diagram illustrating examples of communication devices which can perform a method according to the present disclosure.
  • a first wireless device 100 and a second wireless device 200 may transmit/receive radio signals to/from an external device through a variety of RATs (e.g., LTE and NR).
  • RATs e.g., LTE and NR
  • ⁇ the first wireless device 100 and the second wireless device 200 ⁇ may correspond to ⁇ the wireless device 100a to 100f and the BS 200 ⁇ and/or ⁇ the wireless device 100a to 100f and the wireless device 100a to 100f ⁇ of FIG. 1.
  • the first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally further include one or more transceivers 106 and/or one or more antennas 108.
  • the processor(s) 102 may control the memory(s) 104 and/or the transceiver(s) 106 and may be configured to implement the functions, procedures, and/or methods described in the present disclosure.
  • the processor(s) 102 may process information within the memory(s) 104 to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s) 106.
  • the processor(s) 102 may receive radio signals including second information/signals through the transceiver 106 and then store information obtained by processing the second information/signals in the memory(s) 104.
  • the memory(s) 104 may be connected to the processor(s) 102 and may store a variety of information related to operations of the processor(s) 102.
  • the memory(s) 104 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 102 or for performing the procedures and/or methods described in the present disclosure.
  • the processor(s) 102 and the memory(s) 104 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR).
  • RAT e.g., LTE or NR
  • the transceiver(s) 106 may be connected to the processor(s) 102 and transmit and/or receive radio signals through one or more antennas 108. Each of the transceiver(s) 106 may include a transmitter and/or a receiver. The transceiver(s) 106 may be interchangeably used with radio frequency (RF) unit(s). In the present invention, the wireless device may represent a communication modem/circuit/chip.
  • RF radio frequency
  • the second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally further include one or more transceivers 206 and/or one or more antennas 208.
  • the processor(s) 202 may control the memory(s) 204 and/or the transceiver(s) 206 and may be configured to implement the functions, procedures, and/or methods described in the present disclosure.
  • the processor(s) 202 may process information within the memory(s) 204 to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s) 206.
  • the processor(s) 202 may receive radio signals including fourth information/signals through the transceiver(s) 106 and then store information obtained by processing the fourth information/signals in the memory(s) 204.
  • the memory(s) 204 may be connected to the processor(s) 202 and may store a variety of information related to operations of the processor(s) 202.
  • the memory(s) 204 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 202 or for performing the procedures and/or methods described in the present disclosure.
  • the processor(s) 202 and the memory(s) 204 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR).
  • RAT e.g., LTE or NR
  • the transceiver(s) 206 may be connected to the processor(s) 202 and transmit and/or receive radio signals through one or more antennas 208. Each of the transceiver(s) 206 may include a transmitter and/or a receiver. The transceiver(s) 206 may be interchangeably used with RF unit(s). In the present invention, the wireless device may represent a communication modem/circuit/chip.
  • One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202.
  • the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP).
  • the one or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Unit (SDUs) according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure.
  • PDUs Protocol Data Units
  • SDUs Service Data Unit
  • the one or more processors 102 and 202 may generate messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure.
  • the one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206.
  • the one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure.
  • signals e.g., baseband signals
  • the one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers.
  • the one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof.
  • ASICs Application Specific Integrated Circuits
  • DSPs Digital Signal Processors
  • DSPDs Digital Signal Processing Devices
  • PLDs Programmable Logic Devices
  • FPGAs Field Programmable Gate Arrays
  • the functions, procedures, proposals, and/or methods disclosed in the present disclosure may be implemented using firmware or software and the firmware or software may be configured to include the modules, procedures, or functions.
  • Firmware or software configured to perform the functions, procedures, proposals, and/or methods disclosed in the present disclosure may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202.
  • the functions, procedures, proposals, and/or methods disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and/or a set of commands.
  • the one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands.
  • the one or more memories 104 and 204 may be configured by Read-Only Memories (ROMs), Random Access Memories (RAMs), Electrically Erasable Programmable Read-Only Memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof.
  • the one or more memories 104 and 204 may be located at the interior and/or exterior of the one or more processors 102 and 202.
  • the one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.
  • the one or more transceivers 106 and 206 may transmit user data, control information, and/or radio signals/channels, mentioned in the methods and/or operational flowcharts of the present disclosure, to one or more other devices.
  • the one or more transceivers 106 and 206 may receive user data, control information, and/or radio signals/channels, mentioned in the functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure, from one or more other devices.
  • the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals.
  • the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices.
  • the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.
  • the one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208.
  • the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).
  • the one or more transceivers 106 and 206 may convert received radio signals/channels etc.
  • the one or more transceivers 106 and 206 may convert the user data, control information, radio signals/channels, etc. processed using the one or more processors 102 and 202 from the base band signals into the RF band signals.
  • the one or more transceivers 106 and 206 may include (analog) oscillators and/or filters.
  • the transceivers 106 and 206 can up-convert OFDM baseband signals to a carrier frequency by their (analog) oscillators and/or filters under the control of the processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency.
  • the transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and/or filters under the control of the transceivers 102 and 202.
  • a UE may operate as a transmitting device in uplink (UL) and as a receiving device in downlink (DL).
  • a BS may operate as a receiving device in UL and as a transmitting device in DL.
  • the processor(s) 102 connected to, mounted on or launched in the first wireless device 100 may be configured to perform the UE behaviour according to an implementation of the present disclosure or control the transceiver(s) 106 to perform the UE behaviour according to an implementation of the present disclosure.
  • the processor(s) 202 connected to, mounted on or launched in the second wireless device 200 may be configured to perform the BS behaviour according to an implementation of the present disclosure or control the transceiver(s) 206 to perform the BS behaviour according to an implementation of the present disclosure.
  • FIG. 3 illustrates another example of a wireless device which can perform implementations of the present invention.
  • the wireless device may be implemented in various forms according to a use-case/service (refer to FIG. 1).
  • wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 2 and may be configured by various elements, components, units/portions, and/or modules.
  • each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140.
  • the communication unit may include a communication circuit 112 and transceiver(s) 114.
  • the communication circuit 112 may include the one or more processors 102 and 202 of FIG. 2 and/or the one or more memories 104 and 204 of FIG. 2.
  • the transceiver(s) 114 may include the one or more transceivers 106 and 206 of FIG.
  • the control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls overall operation of the wireless devices. For example, the control unit 120 may control an electric/mechanical operation of the wireless device based on programs/code/commands/information stored in the memory unit 130.
  • the control unit 120 may transmit the information stored in the memory unit 130 to the exterior (e.g., other communication devices) via the communication unit 110 through a wireless/wired interface or store, in the memory unit 130, information received through the wireless/wired interface from the exterior (e.g., other communication devices) via the communication unit 110.
  • the additional components 140 may be variously configured according to types of wireless devices.
  • the additional components 140 may include at least one of a power unit/battery, input/output (I/O) unit (e.g. audio I/O port, video I/O port), a driving unit, and a computing unit.
  • I/O input/output
  • the wireless device may be implemented in the form of, without being limited to, the robot (100a of FIG. 1), the vehicles (100b-1 and 100b-2 of FIG. 1), the XR device (100c of FIG. 1), the hand-held device (100d of FIG. 1), the home appliance (100e of FIG. 1), the IoT device (100f of FIG.
  • the wireless device may be used in a mobile or fixed place according to a use-example/service.
  • the entirety of the various elements, components, units/portions, and/or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110.
  • the control unit 120 and the communication unit 110 may be connected by wire and the control unit 120 and first units (e.g., 130 and 140) may be wirelessly connected through the communication unit 110.
  • Each element, component, unit/portion, and/or module within the wireless devices 100 and 200 may further include one or more elements.
  • the control unit 120 may be configured by a set of one or more processors.
  • control unit 120 may be configured by a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphical processing unit, and a memory control processor.
  • memory 130 may be configured by a random access memory (RAM), a dynamic RAM (DRAM), a read only memory (ROM)), a flash memory, a volatile memory, a non-volatile memory, and/or a combination thereof.
  • FIG. 4 illustrates an example of protocol stacks in a 3GPP based wireless communication system.
  • FIG. 4(a) illustrates an example of a radio interface user plane protocol stack between a UE and a base station (BS)
  • FIG. 4(b) illustrates an example of a radio interface control plane protocol stack between a UE and a BS.
  • the control plane refers to a path through which control messages used to manage call by a UE and a network are transported.
  • the user plane refers to a path through which data generated in an application layer, for example, voice data or Internet packet data are transported.
  • the user plane protocol stack may be divided into a first layer (Layer 1) (i.e., a physical (PHY) layer) and a second layer (Layer 2).
  • Layer 1 i.e., a physical (PHY) layer
  • the control plane protocol stack may be divided into Layer 1 (i.e., a PHY layer), Layer 2, Layer 3 (e.g., a radio resource control (RRC) layer), and a non-access stratum (NAS) layer.
  • Layer 1 i.e., a PHY layer
  • Layer 2 e.g., a radio resource control (RRC) layer
  • NAS non-access stratum
  • Layer 1 and Layer 3 are referred to as an access stratum (AS).
  • the NAS control protocol is terminated in an access management function (AMF) on the network side, and performs functions such as authentication, mobility management, security control and etc.
  • AMF access management function
  • the layer 2 is split into the following sublayers: medium access control (MAC), radio link control (RLC), and packet data convergence protocol (PDCP).
  • MAC medium access control
  • RLC radio link control
  • PDCP packet data convergence protocol
  • the layer 2 is split into the following sublayers: MAC, RLC, PDCP and SDAP.
  • the PHY layer offers to the MAC sublayer transport channels, the MAC sublayer offers to the RLC sublayer logical channels, the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAP sublayer radio bearers.
  • the SDAP sublayer offers to 5G Core Network quality of service (QoS) flows.
  • QoS 5G Core Network quality of service
  • the main services and functions of SDAP include: mapping between a QoS flow and a data radio bearer; marking QoS flow ID (QFI) in both DL and UL packets.
  • QFI QoS flow ID
  • a single protocol entity of SDAP is configured for each individual PDU session.
  • the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5G core (5GC) or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signalling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer; UE cell selection and reselection and control of cell selection and reselection; Inter-RAT mobility); QoS management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; NAS message transfer to/from NAS from/to UE.
  • 5GC 5G core
  • NG-RAN paging initiated by 5G core
  • NG-RAN paging initiated by 5G core
  • security functions including key management
  • SRBs signalling radio bearers
  • DRBs data radio bearers
  • mobility functions including: handover and context transfer; UE cell selection and res
  • the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression: ROHC only; transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers.
  • the main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.
  • the RLC sublayer supports three transmission modes: Transparent Mode (TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM).
  • the RLC configuration is per logical channel with no dependency on numerologies and/or transmission durations.
  • the main services and functions of the RLC sublayer depend on the transmission mode and include: Transfer of upper layer PDUs; sequence numbering independent of the one in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).
  • the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels; scheduling information reporting; error correction through HARQ (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs by means of dynamic scheduling; priority handling between logical channels of one UE by means of logical channel prioritization; padding.
  • a single MAC entity may support multiple numerologies, transmission timings and cells. Mapping restrictions in logical channel prioritization control which numerology(ies), cell(s), and transmission timing(s) a logical channel can use.
  • MAC Different kinds of data transfer services are offered by MAC.
  • multiple types of logical channels are defined i.e. each supporting transfer of a particular type of information.
  • Each logical channel type is defined by what type of information is transferred.
  • Logical channels are classified into two groups: Control Channels and Traffic Channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only.
  • Broadcast Control Channel is a downlink logical channel for broadcasting system control information
  • PCCH paging Control Channel
  • PCCH is a downlink logical channel that transfers paging information
  • Common Control Channel is a logical channel for transmitting control information between UEs and network and used for UEs having no RRC connection with the network
  • DCCH Dedicated Control Channel
  • DTCH Dedicated Traffic Channel
  • a DTCH can exist in both uplink and downlink.
  • BCCH can be mapped to BCH; BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH.
  • CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.
  • FIG. 5 illustrates an example of a frame structure in a 3GPP based wireless communication system.
  • OFDM numerologies e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration
  • SCCS subcarrier spacing
  • TTI transmission time interval
  • symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbols).
  • Each frame is divided into two half-frames, where each of the half-frames has 5 ms duration.
  • Each half-frame consists of 5 subframes, where the duration T sf per subframe is 1 ms.
  • Each subframe is divided into slots and the number of slots in a subframe depends on a subcarrier spacing.
  • Each slot includes 14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP, each slot includes 14 OFDM symbols and, in an extended CP, each slot includes 12 OFDM symbols.
  • a slot includes plural symbols (e.g., 14 or 12 symbols) in the time domain.
  • a resource grid of N size,u grid,x * N RB sc subcarriers and N subframe,u symb OFDM symbols is defined, starting at common resource block (CRB) N start,u grid indicated by higher-layer signaling (e.g. radio resource control (RRC) signaling), where N size,u grid,x is the number of resource blocks in the resource grid and the subscript x is DL for downlink and UL for uplink.
  • RRC radio resource control
  • N RB sc is the number of subcarriers per resource blocks. In the 3GPP based wireless communication system, N RB sc is 12 generally.
  • Each element in the resource grid for the antenna port p and the subcarrier spacing configuration u is referred to as a resource element (RE) and one complex symbol may be mapped to each RE.
  • Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l representing a symbol location relative to a reference point in the time domain.
  • a resource block is defined by 12 consecutive subcarriers in the frequency domain.
  • resource blocks are classified into CRBs and physical resource blocks (PRBs).
  • CRBs are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration u .
  • the center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with 'point A' which serves as a common reference point for resource block grids.
  • PRBs are defined within a bandwidth part (BWP) and numbered from 0 to N size BWP,i -1, where i is the number of the bandwidth part.
  • n PRB n CRB + N size BWP,i , where N size BWP,i is the common resource block where bandwidth part starts relative to CRB 0.
  • the BWP includes a plurality of consecutive resource blocks.
  • a carrier may include a maximum of N (e.g., 5) BWPs.
  • a UE may be configured with one or more BWPs on a given component carrier. Only one BWP among BWPs configured to the UE can active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.
  • FIG. 6 illustrates a data flow example in the 3GPP NR system.
  • Radio bearers are categorized into two groups: data radio bearers (DRB) for user plane data and signalling radio bearers (SRB) for control plane data.
  • DRB data radio bearers
  • SRB signalling radio bearers
  • the MAC PDU is transmitted/received using radio resources through the PHY layer to/from an external device.
  • the MAC PDU arrives to the PHY layer in the form of a transport block.
  • the uplink transport channels UL-SCH and RACH are mapped to physical uplink shared channel (PUSCH) and physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to physical downlink shared channel (PDSCH), physical broad cast channel (PBCH) and PDSCH, respectively.
  • uplink control information (UCI) is mapped to PUCCH
  • downlink control information (DCI) is mapped to PDCCH.
  • a MAC PDU related to UL-SCH is transmitted by a UE via a PUSCH based on an UL grant
  • a MAC PDU related to DL-SCH is transmitted by a BS via a PDSCH based on a DL assignment.
  • the UE performs an initial cell search procedure of acquiring time and frequency synchronization with the cell and detecting a physical cell identity N cell ID of the cell.
  • the UE may obtain (time and/or frequency) synchronization with a cell of the BS by receiving synchronization signals of the cell, e.g. a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the BS and obtain information such as a cell identity (ID).
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • ID cell identity
  • the UE having finished initial cell search may perform the random access procedure to complete access to the BS.
  • the UE may transmit a preamble through a physical random access channel (PRACH), and receive a response message which is a response to the preamble through a PDCCH and PDSCH.
  • PRACH physical random access channel
  • transmission of an additional PRACH and a contention resolution procedure for the PDCCH and a PDSCH corresponding to the PDCCH may be performed.
  • the UE may perform PDCCH/PDSCH reception and PUSCH/PUCCH transmission as a typical procedure of transmission of an uplink/downlink signal.
  • the random access procedure is used for various purposes including initial access, adjustment of uplink synchronization, resource assignment, and handover.
  • the random access procedure takes two distinct forms: a contention-based random access (CBRA) procedure and a contention-free random access (CFRA) procedure.
  • CBRA contention-based random access
  • CFRA contention-free random access
  • the CFRA procedure is used for general operations including initial access, while the CFRA procedure is used for limited operations such as handover, random access triggered by PDCCH order, BFR, request for other SI and etc.
  • the CBRA procedure may include the following four steps. Messages/transmissions in Steps 1 to 4 given below may be referred to as Msg1 to Msg4, respectively.
  • Step 1 Random Access Preamble on RACH in uplink (Msg1 from UE to BS);
  • Step 2 Random Access Response on DL-SCH (Msg2 from BS to UE);
  • Step 3 First scheduled UL transmission on UL-SCH (Msg3 from UE to BS).
  • Step 4 Contention Resolution on DL (Msg4 from BS to UE).
  • the CFRA procedure may include the following three steps.
  • Step 0 Random Access Preamble assignment (from BS to UE);
  • Step 1 Random Access Preamble on RACH in uplink (Msg1 from UE to BS);
  • Step 2 Random Access Response on DL-SCH (Msg2 from BS to UE).
  • the random access procedure is initiated by a PDCCH order, by a MAC entity itself, or by RRC. There is only one random access procedure on-going at any point in time in a MAC entity.
  • a random access procedure is triggered by various events.
  • the events triggering the random access procedure may comprise: initial access from RRC_IDLE; RRC connection re-establishment; DL or UL data arrival during RRC_CONNECTED when UL synchronization status is "non-synchronized"; UL data arrival during RRC_CONNECTED when there is no PUCCH resources for scheduling request (SR) available; SR failure; request by RRC upon synchronization reconfiguration (e.g.
  • SI system information
  • SIBs system information blocks
  • the network configures the UE with the parameters for the Random Access procedure via RRC signaling.
  • the parameters for the Random Access procedure may comprise:
  • preambleReceivedTargetPower initial Random Access Preamble power
  • preambleTransMax the maximum number of Random Access Preamble transmission
  • the following UE variables may be used for the Random Access procedure: PREAMBLE_INDEX ; PREAMBLE_TRANSMISSION_COUNTER ; PREAMBLE_POWER_RAMPING_COUNTER ; PREAMBLE_POWER_RAMPING_STEP ; PREAMBLE_RECEIVED_TARGET_POWER ; PREAMBLE_BACKOFF ; PCMAX ; SCALING_FACTOR_BI ; TEMPORARY_C-RNTI .
  • a MAC entity for the serving cell When a Random Access procedure is initiated on a serving cell, a MAC entity for the serving cell performs a Random Access Resource selection procedure to select a Random Access Preamble with a ra-PreambleIndex and a PRACH occasion, sets PREAMBLE_INDEX to the ra-PreambleIndex , and transmits the Random Access Preamble using the PRACH occasion.
  • the MAC entity monitors a PDCCH for a random access response(s) identified by an RA-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted (in case of CBRA procedure), or a PDCCH identified by the C-RNTI (in case of CFRA procedure), during a random access response window (e.g. while ra-ResponseWindow configured for the Random Access Procedure is running). For example, once the Random Access Preamble is transmitted on the serving cell, the MAC entity:
  • 3>>> sets the PREAMBLE_BACKOFF to value of the BI field of the MAC subPDU using Table 7.2-1 of 3GPP TS 38.321, multiplied with SCALING_FACTOR_B I.
  • Random Access Response contains a MAC subPDU with Random Access Preamble identifier (RAP ID) corresponding to the transmitted PREAMBLE_INDEX :
  • Random Access Response includes a MAC subPDU with RAPID only:
  • 4>>>> indicates a Random Access problem to upper layers (e.g. RRC);
  • Random Access Preamble was selected by MAC among the contention-based Random Access Preambles:
  • the MAC entity may stop ra-ResponseWindow (and hence monitoring for Random Access Response(s)) after successful reception of a Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX .
  • Contention Resolution is based on either C-RNTI on PDCCH of the SpCell or UE Contention Resolution Identity on DL-SCH.
  • 3>>> indicates a Random Access problem to upper layers.
  • 3>>> selects a random back-off time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF ;
  • the MAC entity flushes the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer.
  • a UE In order to transmit data on UL-SCH, a UE shall have uplink resources available to the UE. In order to receive data on DL-SCH, a UE shall have downlink resources available to the UE.
  • the resource allocation includes time domain resource allocation and frequency domain resource allocation.
  • uplink resource allocation is also referred to as uplink grant
  • downlink resource allocation is also referred to as downlink assignment.
  • An uplink grant is either received by the UE dynamically on PDCCH, in a Random Access Response, or configured to the UE semi-persistently by RRC.
  • Downlink assignment is either received by the UE dynamically on the PDCCH, or configured to the UE semi-persistently by RRC signaling from the BS.
  • a UL grant that is configured semi-persistently and DL assignment that is configured semi-persistently are referred to as a configured UL grant and a configured DL assignment, respectively.
  • Type 1 where an uplink grant is provided by RRC, and stored as configured grant
  • configured grant Type 2 where an uplink grant is provided by PDCCH, and stored or cleared as configured uplink grant based on L1 signaling indicating configured uplink grant activation or deactivation.
  • Type 1 and Type 2 are configured by RRC per serving cell and per BWP. Multiple configurations can be active simultaneously only on different serving cells. For Type 2, activation and deactivation are independent among the serving cells. For the same serving cell, the MAC entity is configured with either Type 1 or Type 2.
  • a UE is provided with at least the following parameters via RRC signaling from a BS when the configured grant type 1 is configured:
  • timeDomainAllocation value m which provides a row index m+1 pointing to an allocation table, indicating a combination of a start symbol S and length L and PUSCH mapping type
  • the UE Upon configuration of a configured grant Type 1 for a serving cell by RRC, the UE stores the uplink grant provided by RRC as a configured uplink grant for the indicated serving cell, and initialise or re-initialise the configured uplink grant to start in the symbol according to timeDomainOffset and S (derived from SLIV ), and to reoccur with periodicity .
  • a UE is provided with at least the following parameters via RRC signaling from a BS when the configured gran Type 2 is configured:
  • - cs-RNTI which is CS-RNTI for activation, deactivation, and retransmission
  • the actual uplink grant is provided to the UE by the PDCCH (addressed to CS-RNTI).
  • the HARQ Process ID associated with the first symbol of a UL transmission is derived from the following equation:
  • HARQ Process ID [floor(CURRENT_symbol/ periodicity )] modulo nrofHARQ-Processes ,
  • CURRENT_symbol (SFN ⁇ numberOfSlotsPerFrame ⁇ numberOfSymbolsPerSlot + slot number in the frame ⁇ numberOfSymbolsPerSlot + symbol number in the slot), and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively as specified in TS 38.211.
  • CURRENT_symbol refers to the symbol index of the first transmission occasion of a repetition bundle that takes place.
  • a HARQ process is configured for a configured uplink grant if the configured uplink grant is activated and the associated HARQ process ID is less than nrofHARQ-Processes .
  • configuredGrantTimer may be configured to a UE by a network.
  • Hybrid automatic retransmission request is a method used for error control.
  • HARQ-acknowledgement (ACK) transmitted on DL is used for error control regarding UL data and HARQ-ACK transmitted on UL is used for error control regarding DL data.
  • a BS schedules one or more resource blocks for a UE selected according to a predetermined scheduling rule and transmits data to the UE using the scheduled resource blocks.
  • the BS schedules one or more resource blocks for a UE selected according to a predetermined scheduling rule and the UE transmits data using allocated resources on UL.
  • a transmitting device performing a HARQ operation waits for an ACK signal after transmitting data (e.g., transport block, codeword).
  • a receiving device performing the HARQ operation transmits the ACK signal only when the data has been correctly received and transmits a negative-ACK (NACK) signal when there is an error in the received data.
  • NACK negative-ACK
  • the transmitting device Upon receiving the ACK signal, the transmitting device transmits subsequent (new) data while, upon receiving the NACK signal, the transmitting device retransmits data.
  • error data is stored in a HARQ buffer and initial data is combined with subsequent retransmission data in order to raise reception success rate.
  • the HARQ scheme is categorized as synchronous HARQ and asynchronous HARQ according to retransmission timing and as adaptive HARQ and non-adaptive HARQ depending on whether a channel state is considered during determination of retransmission resources.
  • the retransmission timing is determined by new scheduling or additional signaling. That is, the retransmission timing for error data may be changed by various factors such as channel state.
  • a modulation and coding scheme MCS
  • the number of resource blocks, etc. which are needed for retransmission
  • the MCS, the number of resource blocks, etc. for retransmission are changed according to channel state.
  • retransmission is also performed using 6 resource blocks.
  • retransmission may be performed using resource blocks less or greater in number than 6 according to channel state.
  • a combination of the four HARQ schemes may be considered but an asynchronous adaptive HARQ scheme and a synchronous non-adaptive HARQ scheme are mainly used.
  • the asynchronous adaptive HARQ scheme the retransmission timing and retransmitted resources are adaptively changed according to channel state so as to maximize retransmission efficiency.
  • overhead is increased.
  • the synchronous non-adaptive HARQ scheme since the retransmission timing and retransmission resource allocation are determined by the system, almost no overhead occurs but retransmission efficiency is very low if this scheme is used in an environment in which the channel state is considerably changed.
  • a time delay occurs until the BS receives HARQ-ACK from the UE and transmits retransmission data after transmitting scheduling information and data according to the scheduling information.
  • the time delay occurs due to a channel propagation delay or a time consumed for data decoding/encoding. Accordingly, if new data is transmitted after a HARQ process which is currently in progress is ended, a gap in data transmission occurs due to a time delay.
  • a plurality of independent HARQ processes is used. For example, when an interval between initial transmission and retransmission is 7 time units, 7 independent HARQ processes may be performed to transmit data without a gap.
  • a plurality of parallel HARQ processes enables successive UL/DL transmission while the BS awaits HARQ feedback for previous UL/DL transmission.
  • Each HARQ process is associated with a HARQ buffer of a MAC layer.
  • Each HARQ process manages state variables regarding the number of transmissions of a MAC PDU in the buffer, HARQ feedback for the MAC PDU in the buffer, a current redundancy version, etc.
  • the MAC layer receives HARQ information from lower layers (e.g. PHY).
  • HARQ information may include New Data Indicator (NDI), Transport Block size (TBS), Redundancy Version (RV), and HARQ process identifier (ID).
  • NDI New Data Indicator
  • TBS Transport Block size
  • RV Redundancy Version
  • ID HARQ process identifier
  • a MAC entity includes a HARQ entity for each serving cell with configured uplink, which maintains a number of parallel HARQ processes. Each HARQ process supports one transport block. Each HARQ process is associated with a HARQ process ID.
  • a HARQ entity of a MAC entity shall:
  • the uplink grant is part of a bundle of the configured uplink grant, and may be used for initial transmission, and if no MAC PDU has been obtained for this bundle:
  • uplink grant is addressed to C-RNTI, and the identified HARQ process is configured for a configured uplink grant:
  • uplink grant is part of a bundle of the configured uplink grant, and the PUSCH of the uplink grant overlaps with a PUSCH of another uplink grant received on the PDCCH for this Serving Cell:
  • uplink grant is addressed to C-RNTI, and the identified HARQ process is configured for a configured uplink grant:
  • New transmissions are performed on the resource and with the modulation and coding scheme (MCS) indicated on either PDCCH, Random Access Response, or RRC.
  • MCS modulation and coding scheme
  • Retransmissions are performed on the resource and, if provided, with the MCS indicated on PDCCH, or on the same resource and with the same MCS as was used for last made transmission attempt within a bundle. If the HARQ entity requests a new transmission for a TB, the HARQ process shall:
  • the HARQ process shall:
  • the HARQ process shall:
  • Msg3 is a message transmitted on UL-SCH containing a C-RNTI MAC CE or CCCH SDU, submitted from upper layer and associated with the UE Contention Resolution Identity, as part of a Random Access procedure.
  • FIG. 7 illustrates an example showing a case where UE cannot perform retransmission for PDU via a configured grant during the random access procedure.
  • a UE configured with configured grant it is possible for a UE configured with configured grant to perform a random access procedure (e.g. for beam failure recovery, or when the number of SR transmissions reaches sr-TransMax configured by the network).
  • a random access procedure e.g. for beam failure recovery, or when the number of SR transmissions reaches sr-TransMax configured by the network.
  • HARQ process ID 0 it has been regulated that, for UL transmission with UL grant in Random Access Response, HARQ process ID 0 is used.
  • the PDU A transmitted via the configured resource will be overwritten by PDU B for Msg3 transmission.
  • the UE replaces the PDU A transmitted via the configured resource in the HARQ buffer of HARQ process ID 0 by the PDU B for Msg3 transmission, the UE cannot perform retransmission for the PDU A transmitted via the configured resource.
  • the network may order retransmission of the PDU A stored in HARQ process ID 0. In this case, as the UE already replace the PDU A in the HARQ process ID 0 by the PDU B for Msg3, the network would fail at decoding.
  • the UE if the UE performs new transmission using configured grant associated with HARQ PID 0 after the Msg3 is transmitted, the UE will replace the PDU for Msg3 by the PDU transmitted via configured grant prior to completion of the Random Access procedure. Therefore, the UE may not successfully complete the Random Access procedure as the UE may not perform retransmission of the Msg3.
  • the network is not be able to order retransmission because it does not know which HARQ process ID is used in the UE side, which would cause more significant problem in the system.
  • splitting the HARQ PID for Msg3 transmission and CG so that HARQ process ID collision never happens. For example, changing a HARQ process ID from 0 to N for the Msg3 transmission might be considered. For another example, shifting the HARQ process ID by 1 for CG.
  • these options may have an impact on PHY and RRC as well as MAC since the range of HARQ process IDs should change from [0, N-1] to [0, N].
  • the UE starts or restarts configuredGrantTimer for the corresponding HARQ process ID 0 upon reception of an uplink grant in a random access response or transmission of Msg3.
  • starting configuredGrantTimer may not be sufficient if the length of configuredGrantTimer is not long enough to cover the whole random access procedure.
  • timer based approach As an alternative of the timer based approach, one might consider using a contention resolution timer to prevent use of HARQ process ID 0 after Msg3 transmission or to specify the duration from Msg3 to Msg4 without a timer where HARQ process ID 0 is not to be used. However, this solution cannot prevent the HARQ process ID collision from occurring during the whole random access procedure.
  • the present disclosure proposes the following solution in order to ensure that a random access procedure is performed without being interrupted by a configured grant throughout the whole random access procedure and that transmission (Tx) via a configured grant has enough retransmission opportunities even when the transmission is performed during a random access procedure.
  • FIG. 8 illustrates an example of a flow diagram for UL transmission according to an implementation of the present disclosure.
  • the UE configured with a configured grant skips uplink transmission on the configured grant during a random access procedure (S803) if the configured grant is associated with a HARQ process that is to be used for an Msg3 transmission and of the configured grant occurs after initiating a random access procedure (S801, Yes).
  • the UE when the configured grant occurs after initiating the random access procedure, the UE is allowed to perform uplink transmission on the configured grant (S805) only if the configured grant is associated with a HARQ process that is not to be used for the Msg3 transmission (S801, No).
  • S805 when the configured grant occurs after initiating the random access procedure, the UE is allowed to perform uplink transmission on the configured grant (S805) only if the configured grant is associated with a HARQ process that is not to be used for the Msg3 transmission (S801, No).
  • a HARQ process having HARQ process ID 0 is used for the Msg3 transmission.
  • skipping uplink transmission on a configured grant may comprise generating no MAC PDU for the configured grant even if there is uplink data to be transmitted and/or not transmitting, via the configured grant, a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the random access procedure may be CBRA or CFRA procedure.
  • the UE may switch to a CBRA procedure according to the conditions specified in MAC specification (see 3GPP TS 38.321, for example).
  • a UE of the present disclosure skips uplink transmission on a configured grant if the configured grant is associated with a HARQ process that is to be used for Msg3 transmission and the configured grant occurs between Time Point 1 and Time Point 2.
  • Time Point 1 may be one of the followings: initiation of a random access procedure; or selection of a random access resource; or transmission of a random access preamble.
  • Time Point 2 may be one of the followings: upon successful transmission of an Msg3; or upon successful reception of an Msg4; or upon completion of the random access procedure, which can be either successful or unsuccessful.
  • the UE skips uplink transmission on a configured grant which is associated with a HARQ process ID used for Msg3 transmission and occurs between Time Point 1 and Time Point 2, even if there is uplink data to be transmitted in the UE side.
  • a configured grant which is associated with a HARQ process ID used for Msg3 transmission and occurs between Time Point 1 and Time Point 2 the UE does not generate a MAC PDU even if there is uplink data to be transmitted.
  • the UE does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • a UE is allowed to perform uplink transmission on a configured grant if the configured grant is not associated with a HARQ process which is to be used for a Msg3 transmission; or if the configured grant is associated with a HARQ process which is to be used for a Msg3 transmission but the configured grant occurs out of Time Point 1 and Time Point 2.
  • the UE may perform uplink transmission only when there is uplink data to be transmitted.
  • a UE can operate a timer, for instance, configuredGrantTimer .
  • the UE starts/restarts the timer for a HARQ process which is to be used for the Msg3 transmission when the UE initiates a random access procedure, and/or when the UE selects a random access resource, and/or the UE transmits a random access preamble.
  • the timer is running, the UE skips uplink transmission on a configured grant associated with a HARQ process (e.g., HARQ process ID 0) which is used for the Msg3 transmission.
  • a HARQ process e.g., HARQ process ID 0
  • FIG. 9 illustrates examples of UL transmission on a configured grant considering a random access procedure according to the implementations of the present disclosure.
  • the UE is configured with configured grant by a network.
  • the UE generates configured grants.
  • the UE determines the HARQ process ID associated with the configured grant.
  • the UE transmits a Random Access Preamble (i.e., Msg1) at T1.
  • Msg1 a Random Access Preamble
  • T2 T3 and T4
  • the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the UE when there is a configured grant associated with the HP ID 0 that is used for an Msg3 transmission out of a random access procedure (e.g., while the random access procedure is not on-going, i.e., while there is no on-going random access procedure), the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits, via the configured grant, a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the UE transmits a Random Access Preamble (i.e., Msg1) at T1.
  • Msg1 a Random Access Preamble
  • the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the UE when there is a configured grant associated with the HP ID 1 that is not used for a Msg3 transmission during the random access procedure, the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the UE After completion of the random access procedure, when there is a configured grant associated with the HP ID 1 out of a random access procedure (e.g., while the random access procedure is not on-going), the UE transmits the UL data using the configured grant.
  • the UE after completion of the random access procedure, when there is a configured grant associated with the HP ID 0 out of a random access procedure, the UE transmits the UL data using the configured grant.
  • the UL transmission on the configured grant may be skipped irrespective of whether a configured grant timer for the HARQ process used for an Msg3 transmission is running.
  • FIG. 10 illustrates an example of UL transmission on a configured grant considering a random access procedure and a timer according to an implementation of the present disclosure.
  • the UE is configured with configured grant by a network.
  • the UE generates configured grants.
  • the UE determines the HARQ process ID associated with the configured grant.
  • the UE transmits a contention-based Random Access Preamble (Msg1) at T1
  • the UE starts a timer for a HARQ process which is to be used for the Msg3 transmission.
  • T2 and T4 when there is a configured grant associated with the HP ID 0 which is to be used for the Msg3 transmission while the timer is running, the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the UE when there is a configured grant associated with the HP ID 0 which is to be used for the Msg3 transmission while the timer is not running, the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
  • the random access procedure can be performed without being interrupted by a configured grant throughout the whole random access procedure, and transmission via a configured grant can have enough retransmission chances even when the transmission is performed during a random access procedure.
  • the implementations of the present disclosure are applicable to a network node (e.g., BS), a UE, or other devices in a wireless communication system.
  • a network node e.g., BS
  • UE User Equipment

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Abstract

In the present disclosure, for a configured grant occurring while a random access procedure is on-going, the user equipment skips uplink transmission on the configured grant if the configured grant is associated with a HARQ process used for a Msg3 transmission of the random access procedure, and performs the uplink transmission on the configured grant if the configured grant is not associated with the HARQ process used for the Msg3 transmission.

Description

METHOD OF TRANSMITTING UPLINK SIGNALS, AND DEVICE THEREFOR
The present invention relates to a wireless communication system.
Introduction of new radio communication technologies has led to increases in the number of user equipments (UEs) to which a base station (BS) provides services in a prescribed resource region, and has also led to increases in the amount of data and control information that the BS transmits to the UEs. Due to typically limited resources available to the BS for communication with the UE(s), new techniques are needed by which the BS utilizes the limited radio resources to efficiently receive/transmit uplink/downlink data and/or uplink/downlink control information.
Various types of signals, including data signals and control signals, are communicated via the UL and DL. Scheduling of such communications is typically performed, to achieve improved efficiency, latency, and/or reliability. Overcoming delay or latency has become an important challenge in applications whose performance critically depends on delay/latency.
The technical objects that can be achieved through the present invention are not limited to what has been particularly described hereinabove and other technical objects not described herein will be more clearly understood by persons skilled in the art from the following detailed description.
As an aspect of the present disclosure, provided herein is a method for transmitting uplink signals by a user equipment in a wireless communication system. The method comprises: determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure; skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and performing the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process.
As another aspect of the present disclosure, provided herein is a device for a user equipment of transmitting uplink signals in a wireless communication system. The device comprises: at least one processor; and at least one computer memory that is operably connectable to the at least one processor and that has stored thereon instructions which, when executed, cause the at least one processor to perform operations. The operations comprises: determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure; skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and performing, via a transceiver of the user equipment, the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process..
In each aspect of the present disclosure, the method or operations may further comprise: starting a configured grant timer for the HARQ process when transmitting a random access preamble (Msg1) of the random access procedure.
In each aspect of the present disclosure, skipping the uplink transmission on the first configured grant may comprise: generating no MAC PDU for the first configured grant.
In each aspect of the present disclosure, skipping the uplink transmission on the first configured grant may comprise: skipping transmitting a MAC PDU stored in a HARQ buffer of the HARQ process associated with the first configured grant.
In each aspect of the present disclosure, the method or operations may further comprise: performing, via the transceiver of the user equipment, uplink transmission on a second configured grant. The second configured grant may occur while the random access procedure is not on-going.
In each aspect of the present disclosure, skipping the uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process may comprise: skipping the uplink transmission on the first configured grant irrespective of whether a configured grant timer for the HARQ process is running.
In each aspect of the present disclosure, the first configured grant may comprise a configured grant occurring after transmission of a random access preamble of the random access procedure and before completion of the random access procedure.
In each aspect of the present disclosure, the user equipment is an autonomous vehicle that communicates with at least a mobile terminal, a network, and another autonomous vehicle other than the user equipment.
The above technical solutions are merely some parts of the implementations of the present disclosure and various implementations into which the technical features of the present disclosure are incorporated can be derived and understood by persons skilled in the art from the following detailed description of the present disclosure.
In some scenarios, implementations of the present disclosure may provide one or more of the following advantages. In some scenarios, radio communication signals can be more efficiently transmitted and/or received. Therefore, overall throughput of a radio communication system can be improved.
According to some implementations of the present disclosure, delay/latency occurring during communication between a user equipment and a BS may be reduced.
Also, signals in a new radio access technology system can be transmitted and/or received more effectively.
Also, transmission via a configured grant can have enough retransmission opportunities even when the transmission occurs during a random access procedure.
Also, a random access procedure can be performed without being interrupted by a configured grant throughout the whole random access procedure.
It will be appreciated by persons skilled in the art that the effects that can be achieved through the present disclosure are not limited to what has been particularly described hereinabove and other advantages of the present disclosure will be more clearly understood from the following detailed description.
The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention:
FIG. 1 illustrates an example of a communication system 1 to which implementations of the present disclosure is applied;
FIG. 2 is a block diagram illustrating examples of communication devices which can perform a method according to the present disclosure;
FIG. 3 illustrates another example of a wireless device which can perform implementations of the present invention;
FIG. 4 illustrates an example of protocol stacks in a third generation partnership project (3GPP) based wireless communication system;
FIG. 5 illustrates an example of a frame structure in a 3GPP based wireless communication system;
FIG. 6 illustrates a data flow example in the 3GPP new radio (NR) system;
FIG. 7 illustrates an example showing a case where UE cannot perform retransmission for PDU via a configured grant during the random access procedure;
FIG. 8 illustrates an example of a flow diagram for UL transmission according to an implementation of the present disclosure;
FIG. 9 illustrates examples of UL transmission on a configured grant considering a random access procedure according to the implementations of the present disclosure; and
FIG. 10 illustrates an example of UL transmission on a configured grant considering a random access procedure and a timer according to an implementation of the present disclosure.
Reference will now be made in detail to the exemplary implementations of the present disclosure, examples of which are illustrated in the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary implementations of the present disclosure, rather than to show the only implementations that can be implemented according to the disclosure. The following detailed description includes specific details in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without such specific details.
The following techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of the multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, and a multicarrier frequency division multiple access (MC-FDMA) system. CDMA may be embodied through radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be embodied through radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA may be embodied through radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is a part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolved version of 3GPP LTE.
For convenience of description, implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.
For terms and technologies which are not specifically described among the terms of and technologies employed in the present disclosure, the wireless communication standard documents published before the present disclosure may be referenced. For example, the following documents may be referenced.
3GPP LTE
- 3GPP TS 36.211: Physical channels and modulation
- 3GPP TS 36.212: Multiplexing and channel coding
- 3GPP TS 36.213: Physical layer procedures
- 3GPP TS 36.214: Physical layer; Measurements
- 3GPP TS 36.300: Overall description
- 3GPP TS 36.304: User Equipment (UE) procedures in idle mode
- 3GPP TS 36.314: Layer 2 - Measurements
- 3GPP TS 36.321: Medium Access Control (MAC) protocol
- 3GPP TS 36.322: Radio Link Control (RLC) protocol
- 3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)
- 3GPP TS 36.331: Radio Resource Control (RRC) protocol
3GPP NR (e.g. 5G)
- 3GPP TS 38.211: Physical channels and modulation
- 3GPP TS 38.212: Multiplexing and channel coding
- 3GPP TS 38.213: Physical layer procedures for control
- 3GPP TS 38.214: Physical layer procedures for data
- 3GPP TS 38.215: Physical layer measurements
- 3GPP TS 38.300: Overall description
- 3GPP TS 38.304: User Equipment (UE) procedures in idle mode and in RRC inactive state
- 3GPP TS 38.321: Medium Access Control (MAC) protocol
- 3GPP TS 38.322: Radio Link Control (RLC) protocol
- 3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)
- 3GPP TS 38.331: Radio Resource Control (RRC) protocol
- 3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)
- 3GPP TS 37.340: Multi-connectivity; Overall description
In the present disclosure, a user equipment (UE) may be a fixed or mobile device. Examples of the UE include various devices that transmit and receive user data and/or various kinds of control information to and from a base station (BS). In the present disclosure, a BS generally refers to a fixed station that performs communication with a UE and/or another BS, and exchanges various kinds of data and control information with the UE and another BS. The BS may be referred to as an advanced base station (ABS), a node-B (NB), an evolved node-B (eNB), a base transceiver system (BTS), an access point (AP), a processing server (PS), etc. Especially, a BS of the UMTS is referred to as a NB, a BS of the enhanced packet core (EPC) / long term evolution (LTE) system is referred to as an eNB, and a BS of the new radio (NR) system is referred to as a gNB.
In the present disclosure, a node refers to a point capable of transmitting/receiving a radio signal through communication with a UE. Various types of BSs may be used as nodes irrespective of the terms thereof. For example, a BS, a node B (NB), an e-node B (eNB), a pico-cell eNB (PeNB), a home eNB (HeNB), a relay, a repeater, etc. may be a node. In addition, the node may not be a BS. For example, the node may be a radio remote head (RRH) or a radio remote unit (RRU). The RRH or RRU generally has a lower power level than a power level of a BS. Since the RRH or RRU (hereinafter, RRH/RRU) is generally connected to the BS through a dedicated line such as an optical cable, cooperative communication between RRH/RRU and the BS can be smoothly performed in comparison with cooperative communication between BSs connected by a radio line. At least one antenna is installed per node. The antenna may include a physical antenna or an antenna port or a virtual antenna.
In the present disclosure, the term "cell" may refer to a geographic area to which one or more nodes provide a communication system, or refer to radio resources. A "cell" of a geographic area may be understood as coverage within which a node can provide service using a carrier and a "cell" as radio resources (e.g. time-frequency resources) is associated with bandwidth (BW) which is a frequency range configured by the carrier. The "cell" associated with the radio resources is defined by a combination of downlink resources and uplink resources, for example, a combination of a downlink (DL) component carrier (CC) and an uplink (UL) CC. The cell may be configured by downlink resources only, or may be configured by downlink resources and uplink resources. Since DL coverage, which is a range within which the node is capable of transmitting a valid signal, and UL coverage, which is a range within which the node is capable of receiving the valid signal from the UE, depends upon a carrier carrying the signal, the coverage of the node may be associated with coverage of the "cell" of radio resources used by the node. Accordingly, the term "cell" may be used to represent service coverage of the node sometimes, radio resources at other times, or a range that signals using the radio resources can reach with valid strength at other times.
In the present disclosure, a physical downlink control channel (PDCCH), and a physical downlink shared channel (PDSCH) refer to a set of time-frequency resources or resource elements (REs) carrying downlink control information (DCI), and a set of time-frequency resources or REs carrying downlink data, respectively. In addition, a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH) and a physical random access channel (PRACH) refer to a set of time-frequency resources or REs carrying uplink control information (UCI), a set of time-frequency resources or REs carrying uplink data and a set of time-frequency resources or REs carrying random access signals, respectively.
In carrier aggregation (CA), two or more CCs are aggregated. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. CA is supported for both contiguous and non-contiguous CCs. When CA is configured the UE only has one radio resource control (RRC) connection with the network. At RRC connection establishment/re-establishment/handover, one serving cell provides the non-access stratum (NAS) mobility information, and at RRC connection re-establishment/handover, one serving cell provides the security input. This cell is referred to as the Primary Cell (PCell). The PCell is a cell, operating on the primary frequency, in which the UE either performs the initial connection establishment procedure or initiates the connection re-establishment procedure. Depending on UE capabilities, Secondary Cells (SCells) can be configured to form together with the PCell a set of serving cells. An SCell is a cell providing additional radio resources on top of Special Cell. The configured set of serving cells for a UE therefore always consists of one PCell and one or more SCells. In the present disclosure, for dual connectivity (DC) operation, the term "special Cell" refers to the PCell of the master cell group (MCG) or the PSCell of the secondary cell group (SCG), and otherwise the term Special Cell refers to the PCell. An SpCell supports physical uplink control channel (PUCCH) transmission and contention-based random access, and is always activated. The MCG is a group of serving cells associated with a master node, comprising of the SpCell (PCell) and optionally one or more SCells. The SCG is the subset of serving cells associated with a secondary node, comprising of the PSCell and zero or more SCells, for a UE configured with DC. For a UE in RRC_CONNECTED not configured with CA/DC there is only one serving cell comprising of the PCell. For a UE in RRC_CONNECTED configured with CA/DC the term "serving cells" is used to denote the set of cells comprising of the SpCell(s) and all SCells.
The MCG is a group of serving cells associated with a master BS which terminates at least S1-MME, and the SCG is a group of serving cells associated with a secondary BS that is providing additional radio resources for the UE but is not the master BS. The SCG includes a primary SCell (PSCell) and optionally one or more SCells. In DC, two MAC entities are configured in the UE: one for the MCG and one for the SCG. Each MAC entity is configured by RRC with a serving cell supporting PUCCH transmission and contention based Random Access. In the present disclosure, the term SpCell refers to such cell, whereas the term SCell refers to other serving cells. The term SpCell either refers to the PCell of the MCG or the PSCell of the SCG depending on if the MAC entity is associated to the MCG or the SCG, respectively.
In the present disclosure, monitoring a channel refers to attempting to decode the channel. For example, monitoring a physical downlink control channel (PDCCH) refers to attempting to decode PDCCH(s) (or PDCCH candidates).
In the present disclosure, "C-RNTI" refers to a cell RNTI, "SI-RNTI" refers to a system information RNTI, "P-RNTI" refers to a paging RNTI, "RA-RNTI" refers to a random access RNTI, "SC-RNTI" refers to a single cell RNTI", "SL-RNTI" refers to a sidelink RNTI, "SPS C-RNTI" refers to a semi-persistent scheduling C-RNTI, and "CS-RNTI" refers to a configured scheduling RNTI.
FIG. 1 illustrates an example of a communication system 1 to which implementations of the present disclosure is applied.
Three main requirement categories for 5G include (1) a category of enhanced mobile broadband (eMBB), (2) a category of massive machine type communication (mMTC), and (3) a category of ultra-reliable and low latency communications (URLLC).
Partial use cases may require a plurality of categories for optimization and other use cases may focus only upon one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable method.
eMBB far surpasses basic mobile Internet access and covers abundant bidirectional work and media and entertainment applications in cloud and augmented reality. Data is one of 5G core motive forces and, in a 5G era, a dedicated voice service may not be provided for the first time. In 5G, it is expected that voice will be simply processed as an application program using data connection provided by a communication system. Main causes for increased traffic volume are due to an increase in the size of content and an increase in the number of applications requiring high data transmission rate. A streaming service (of audio and video), conversational video, and mobile Internet access will be more widely used as more devices are connected to the Internet. These many application programs require connectivity of an always turned-on state in order to push real-time information and alarm for users. Cloud storage and applications are rapidly increasing in a mobile communication platform and may be applied to both work and entertainment. The cloud storage is a special use case which accelerates growth of uplink data transmission rate. 5G is also used for remote work of cloud. When a tactile interface is used, 5G demands much lower end-to-end latency to maintain user good experience. Entertainment, for example, cloud gaming and video streaming, is another core element which increases demand for mobile broadband capability. Entertainment is essential for a smartphone and a tablet in any place including high mobility environments such as a train, a vehicle, and an airplane. Other use cases are augmented reality for entertainment and information search. In this case, the augmented reality requires very low latency and instantaneous data volume.
In addition, one of the most expected 5G use cases relates a function capable of smoothly connecting embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential IoT devices will reach 204 hundred million up to the year of 2020. An industrial IoT is one of categories of performing a main role enabling a smart city, asset tracking, smart utility, agriculture, and security infrastructure through 5G.
URLLC includes a new service that will change industry through remote control of main infrastructure and an ultra-reliable/available low-latency link such as a self-driving vehicle. A level of reliability and latency is essential to control a smart grid, automatize industry, achieve robotics, and control and adjust a drone.
5G is a means of providing streaming evaluated as a few hundred megabits per second to gigabits per second and may complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such fast speed is needed to deliver TV in resolution of 4K or more (6K, 8K, and more), as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games. A specific application program may require a special network configuration. For example, for VR games, gaming companies need to incorporate a core server into an edge network server of a network operator in order to minimize latency.
Automotive is expected to be a new important motivated force in 5G together with many use cases for mobile communication for vehicles. For example, entertainment for passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect connection of high quality regardless of their locations and speeds. Another use case of an automotive field is an AR dashboard. The AR dashboard causes a driver to identify an object in the dark in addition to an object seen from a front window and displays a distance from the object and a movement of the object by overlapping information talking to the driver. In the future, a wireless module enables communication between vehicles, information exchange between a vehicle and supporting infrastructure, and information exchange between a vehicle and other connected devices (e.g., devices accompanied by a pedestrian). A safety system guides alternative courses of a behavior so that a driver may drive more safely drive, thereby lowering the danger of an accident. The next stage will be a remotely controlled or self-driven vehicle. This requires very high reliability and very fast communication between different self-driven vehicles and between a vehicle and infrastructure. In the future, a self-driven vehicle will perform all driving activities and a driver will focus only upon abnormal traffic that the vehicle cannot identify. Technical requirements of a self-driven vehicle demand ultra-low latency and ultra-high reliability so that traffic safety is increased to a level that cannot be achieved by human being.
A smart city and a smart home/building mentioned as a smart society will be embedded in a high-density wireless sensor network. A distributed network of an intelligent sensor will identify conditions for costs and energy-efficient maintenance of a city or a home. Similar configurations may be performed for respective households. All of temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, real-time HD video may be demanded by a specific type of device to perform monitoring.
Consumption and distribution of energy including heat or gas is distributed at a higher level so that automated control of the distribution sensor network is demanded. The smart grid collects information and connects the sensors to each other using digital information and communication technology so as to act according to the collected information. Since this information may include behaviors of a supply company and a consumer, the smart grid may improve distribution of fuels such as electricity by a method having efficiency, reliability, economic feasibility, production sustainability, and automation. The smart grid may also be regarded as another sensor network having low latency.
Mission critical application (e.g. e-health) is one of 5G use scenarios. A health part contains many application programs capable of enjoying benefit of mobile communication. A communication system may support remote treatment that provides clinical treatment in a faraway place. Remote treatment may aid in reducing a barrier against distance and improve access to medical services that cannot be continuously available in a faraway rural area. Remote treatment is also used to perform important treatment and save lives in an emergency situation. The wireless sensor network based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.
Wireless and mobile communication gradually becomes important in the field of an industrial application. Wiring is high in installation and maintenance cost. Therefore, a possibility of replacing a cable with reconstructible wireless links is an attractive opportunity in many industrial fields. However, in order to achieve this replacement, it is necessary for wireless connection to be established with latency, reliability, and capacity similar to those of the cable and management of wireless connection needs to be simplified. Low latency and a very low error probability are new requirements when connection to 5G is needed.
Logistics and freight tracking are important use cases for mobile communication that enables inventory and package tracking anywhere using a location-based information system. The use cases of logistics and freight typically demand low data rate but require location information with a wide range and reliability.
Referring to FIG. 1, the communication system 1 includes wireless devices, base stations (BSs), and a network. Although FIG. 1 illustrates a 5G network as an example of the network of the communication system 1, the implementations of the present disclosure are not limited to the 5G system, and can be applied to the future communication system beyond the 5G system.
The BSs and the network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS/network node with respect to other wireless devices.
The wireless devices represent devices performing communication using radio access technology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE)) and may be referred to as communication/radio/5G devices. The wireless devices may include, without being limited to, a robot 100a, vehicles 100b-1 and 100b-2, an eXtended Reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an Artificial Intelligence (AI) device/server 400. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) device and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter.
In the present disclosure, the wireless devices 100a to 100f may be called user equipments (UEs). A user equipment (UE) may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an unmanned aerial vehicle (UAV), an artificial intelligence (AI) module, a robot, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or a financial device), a security device, a weather/environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field. The unmanned aerial vehicle (UAV) may be, for example, an aircraft aviated by a wireless control signal without a human being onboard. The VR device may include, for example, a device for implementing an object or a background of the virtual world. The AR device may include, for example, a device implemented by connecting an object or a background of the virtual world to an object or a background of the real world. The MR device may include, for example, a device implemented by merging an object or a background of the virtual world into an object or a background of the real world. The hologram device may include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information, using an interference phenomenon of light generated when two laser lights called holography meet. The public safety device may include, for example, an image relay device or an image device that is wearable on the body of a user. The MTC device and the IoT device may be, for example, devices that do not require direct human intervention or manipulation. For example, the MTC device and the IoT device may include smartmeters, vending machines, thermometers, smartbulbs, door locks, or various sensors. The medical device may be, for example, a device used for the purpose of diagnosing, treating, relieving, curing, or preventing disease. For example, the medical device may be a device used for the purpose of diagnosing, treating, relieving, or correcting injury or impairment. For example, the medical device may be a device used for the purpose of inspecting, replacing, or modifying a structure or a function. For example, the medical device may be a device used for the purpose of adjusting pregnancy. For example, the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for procedure. The security device may be, for example, a device installed to prevent a danger that may arise and to maintain safety. For example, the security device may be a camera, a CCTV, a recorder, or a black box. The FinTech device may be, for example, a device capable of providing a financial service such as mobile payment. For example, the FinTech device may include a payment device or a point of sales (POS) system. The weather/environment device may include, for example, a device for monitoring or predicting a weather/environment.
The wireless devices 100a to 100f may be connected to the network 300 via the BSs 200. An AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network. Although the wireless devices 100a to 100f may communicate with each other through the BSs 200/network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs/network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g. Vehicle-to-Vehicle (V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.
Wireless communication/ connections 150a and 150b may be established between the wireless devices 100a to 100f/BS 200-BS 200. Herein, the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as uplink/downlink communication 150a and sidelink communication 150b (or D2D communication). The wireless devices and the BSs/the wireless devices may transmit/receive radio signals to/from each other through the wireless communication/ connections 150a and 150b. For example, the wireless communication/ connections 150a and 150b may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.
FIG. 2 is a block diagram illustrating examples of communication devices which can perform a method according to the present disclosure.
Referring to FIG. 2, a first wireless device 100 and a second wireless device 200 may transmit/receive radio signals to/from an external device through a variety of RATs (e.g., LTE and NR). In FIG. 2, {the first wireless device 100 and the second wireless device 200} may correspond to {the wireless device 100a to 100f and the BS 200} and/or {the wireless device 100a to 100f and the wireless device 100a to 100f} of FIG. 1.
The first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally further include one or more transceivers 106 and/or one or more antennas 108. The processor(s) 102 may control the memory(s) 104 and/or the transceiver(s) 106 and may be configured to implement the functions, procedures, and/or methods described in the present disclosure. For example, the processor(s) 102 may process information within the memory(s) 104 to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s) 106. The processor(s) 102 may receive radio signals including second information/signals through the transceiver 106 and then store information obtained by processing the second information/signals in the memory(s) 104. The memory(s) 104 may be connected to the processor(s) 102 and may store a variety of information related to operations of the processor(s) 102. For example, the memory(s) 104 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 102 or for performing the procedures and/or methods described in the present disclosure. Herein, the processor(s) 102 and the memory(s) 104 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 106 may be connected to the processor(s) 102 and transmit and/or receive radio signals through one or more antennas 108. Each of the transceiver(s) 106 may include a transmitter and/or a receiver. The transceiver(s) 106 may be interchangeably used with radio frequency (RF) unit(s). In the present invention, the wireless device may represent a communication modem/circuit/chip.
The second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally further include one or more transceivers 206 and/or one or more antennas 208. The processor(s) 202 may control the memory(s) 204 and/or the transceiver(s) 206 and may be configured to implement the functions, procedures, and/or methods described in the present disclosure. For example, the processor(s) 202 may process information within the memory(s) 204 to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s) 206. The processor(s) 202 may receive radio signals including fourth information/signals through the transceiver(s) 106 and then store information obtained by processing the fourth information/signals in the memory(s) 204. The memory(s) 204 may be connected to the processor(s) 202 and may store a variety of information related to operations of the processor(s) 202. For example, the memory(s) 204 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 202 or for performing the procedures and/or methods described in the present disclosure. Herein, the processor(s) 202 and the memory(s) 204 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 206 may be connected to the processor(s) 202 and transmit and/or receive radio signals through one or more antennas 208. Each of the transceiver(s) 206 may include a transmitter and/or a receiver. The transceiver(s) 206 may be interchangeably used with RF unit(s). In the present invention, the wireless device may represent a communication modem/circuit/chip.
Hereinafter, hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). The one or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Unit (SDUs) according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed in the present disclosure.
The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors 102 and 202. The functions, procedures, proposals, and/or methods disclosed in the present disclosure may be implemented using firmware or software and the firmware or software may be configured to include the modules, procedures, or functions. Firmware or software configured to perform the functions, procedures, proposals, and/or methods disclosed in the present disclosure may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202. The functions, procedures, proposals, and/or methods disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and/or a set of commands.
The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands. The one or more memories 104 and 204 may be configured by Read-Only Memories (ROMs), Random Access Memories (RAMs), Electrically Erasable Programmable Read-Only Memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof. The one or more memories 104 and 204 may be located at the interior and/or exterior of the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.
The one or more transceivers 106 and 206 may transmit user data, control information, and/or radio signals/channels, mentioned in the methods and/or operational flowcharts of the present disclosure, to one or more other devices. The one or more transceivers 106 and 206 may receive user data, control information, and/or radio signals/channels, mentioned in the functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure, from one or more other devices. For example, the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices. The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208. In the present disclosure, the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). The one or more transceivers 106 and 206 may convert received radio signals/channels etc. from RF band signals into baseband signals in order to process received user data, control information, radio signals/channels, etc. using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals/channels, etc. processed using the one or more processors 102 and 202 from the base band signals into the RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and/or filters. For example, the transceivers 106 and 206 can up-convert OFDM baseband signals to a carrier frequency by their (analog) oscillators and/or filters under the control of the processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and/or filters under the control of the transceivers 102 and 202.
In the implementations of the present disclosure, a UE may operate as a transmitting device in uplink (UL) and as a receiving device in downlink (DL). In the implementations of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. Hereinafter, for convenience of description, it is mainly assumed that the first wireless device 100 acts as the UE, and the second wireless device 200 acts as the BS, unless otherwise mentioned or described. For example, the processor(s) 102 connected to, mounted on or launched in the first wireless device 100 may be configured to perform the UE behaviour according to an implementation of the present disclosure or control the transceiver(s) 106 to perform the UE behaviour according to an implementation of the present disclosure. The processor(s) 202 connected to, mounted on or launched in the second wireless device 200 may be configured to perform the BS behaviour according to an implementation of the present disclosure or control the transceiver(s) 206 to perform the BS behaviour according to an implementation of the present disclosure.
FIG. 3 illustrates another example of a wireless device which can perform implementations of the present invention. The wireless device may be implemented in various forms according to a use-case/service (refer to FIG. 1).
Referring to FIG. 3, wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 2 and may be configured by various elements, components, units/portions, and/or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit may include a communication circuit 112 and transceiver(s) 114. For example, the communication circuit 112 may include the one or more processors 102 and 202 of FIG. 2 and/or the one or more memories 104 and 204 of FIG. 2. For example, the transceiver(s) 114 may include the one or more transceivers 106 and 206 of FIG. 2 and/or the one or more antennas 108 and 208 of FIG. 2. The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls overall operation of the wireless devices. For example, the control unit 120 may control an electric/mechanical operation of the wireless device based on programs/code/commands/information stored in the memory unit 130. The control unit 120 may transmit the information stored in the memory unit 130 to the exterior (e.g., other communication devices) via the communication unit 110 through a wireless/wired interface or store, in the memory unit 130, information received through the wireless/wired interface from the exterior (e.g., other communication devices) via the communication unit 110.
The additional components 140 may be variously configured according to types of wireless devices. For example, the additional components 140 may include at least one of a power unit/battery, input/output (I/O) unit (e.g. audio I/O port, video I/O port), a driving unit, and a computing unit. The wireless device may be implemented in the form of, without being limited to, the robot (100a of FIG. 1), the vehicles (100b-1 and 100b-2 of FIG. 1), the XR device (100c of FIG. 1), the hand-held device (100d of FIG. 1), the home appliance (100e of FIG. 1), the IoT device (100f of FIG. 1), a digital broadcast terminal, a hologram device, a public safety device, an MTC device, a medicine device, a Fintech device (or a finance device), a security device, a climate/environment device, the AI server/device (400 of FIG. 1), the BSs (200 of FIG. 1), a network node, etc. The wireless device may be used in a mobile or fixed place according to a use-example/service.
In FIG. 3, the entirety of the various elements, components, units/portions, and/or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected by wire and the control unit 120 and first units (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit/portion, and/or module within the wireless devices 100 and 200 may further include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphical processing unit, and a memory control processor. As another example, the memory 130 may be configured by a random access memory (RAM), a dynamic RAM (DRAM), a read only memory (ROM)), a flash memory, a volatile memory, a non-volatile memory, and/or a combination thereof.
FIG. 4 illustrates an example of protocol stacks in a 3GPP based wireless communication system.
In particular, FIG. 4(a) illustrates an example of a radio interface user plane protocol stack between a UE and a base station (BS) and FIG. 4(b) illustrates an example of a radio interface control plane protocol stack between a UE and a BS. The control plane refers to a path through which control messages used to manage call by a UE and a network are transported. The user plane refers to a path through which data generated in an application layer, for example, voice data or Internet packet data are transported. Referring to FIG. 4(a), the user plane protocol stack may be divided into a first layer (Layer 1) (i.e., a physical (PHY) layer) and a second layer (Layer 2). Referring to FIG. 4(b), the control plane protocol stack may be divided into Layer 1 (i.e., a PHY layer), Layer 2, Layer 3 (e.g., a radio resource control (RRC) layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 and Layer 3 are referred to as an access stratum (AS).
The NAS control protocol is terminated in an access management function (AMF) on the network side, and performs functions such as authentication, mobility management, security control and etc.
In the 3GPP LTE system, the layer 2 is split into the following sublayers: medium access control (MAC), radio link control (RLC), and packet data convergence protocol (PDCP). In the 3GPP New Radio (NR) system, the layer 2 is split into the following sublayers: MAC, RLC, PDCP and SDAP. The PHY layer offers to the MAC sublayer transport channels, the MAC sublayer offers to the RLC sublayer logical channels, the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAP sublayer radio bearers. The SDAP sublayer offers to 5G Core Network quality of service (QoS) flows.
In the 3GPP NR system, the main services and functions of SDAP include: mapping between a QoS flow and a data radio bearer; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.
In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5G core (5GC) or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signalling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer; UE cell selection and reselection and control of cell selection and reselection; Inter-RAT mobility); QoS management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; NAS message transfer to/from NAS from/to UE.
In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression: ROHC only; transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.
The RLC sublayer supports three transmission modes: Transparent Mode (TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM). The RLC configuration is per logical channel with no dependency on numerologies and/or transmission durations. In the 3GPP NR system, the main services and functions of the RLC sublayer depend on the transmission mode and include: Transfer of upper layer PDUs; sequence numbering independent of the one in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).
In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels; scheduling information reporting; error correction through HARQ (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs by means of dynamic scheduling; priority handling between logical channels of one UE by means of logical channel prioritization; padding. A single MAC entity may support multiple numerologies, transmission timings and cells. Mapping restrictions in logical channel prioritization control which numerology(ies), cell(s), and transmission timing(s) a logical channel can use. Different kinds of data transfer services are offered by MAC. To accommodate different kinds of data transfer services, multiple types of logical channels are defined i.e. each supporting transfer of a particular type of information. Each logical channel type is defined by what type of information is transferred. Logical channels are classified into two groups: Control Channels and Traffic Channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only. Broadcast Control Channel (BCCH) is a downlink logical channel for broadcasting system control information, paging Control Channel (PCCH) is a downlink logical channel that transfers paging information, system information change notifications and indications of ongoing PWS broadcasts, Common Control Channel (CCCH) is a logical channel for transmitting control information between UEs and network and used for UEs having no RRC connection with the network, and Dedicated Control Channel (DCCH) is a point-to-point bi-directional logical channel that transmits dedicated control information between a UE and the network and used by UEs having an RRC connection. Dedicated Traffic Channel (DTCH) is a point-to-point logical channel, dedicated to one UE, for the transfer of user information. A DTCH can exist in both uplink and downlink. In Downlink, the following connections between logical channels and transport channels exist: BCCH can be mapped to BCH; BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In Uplink, the following connections between logical channels and transport channels exist: CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.
FIG. 5 illustrates an example of a frame structure in a 3GPP based wireless communication system.
The frame structure illustrated in FIG. 5 is purely exemplary and the number of subframes, the number of slots, and/or the number of symbols in a frame may be variously changed. In the 3GPP based wireless communication system, OFDM numerologies (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) may be differently configured between a plurality of cells aggregated for one UE. For example, if a UE is configured with different SCSs for cells aggregated for the cell, an (absolute time) duration of a time resource (e.g. a subframe, a slot, or a TTI) including the same number of symbols may be different among the aggregated cells. Herein, symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbols).
Referring to FIG. 5, downlink and uplink transmissions are organized into frames. Each frame has T f = 10 ms duration. Each frame is divided into two half-frames, where each of the half-frames has 5 ms duration. Each half-frame consists of 5 subframes, where the duration T sf per subframe is 1 ms. Each subframe is divided into slots and the number of slots in a subframe depends on a subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP, each slot includes 14 OFDM symbols and, in an extended CP, each slot includes 12 OFDM symbols. The numerology is based on exponentially scalable subcarrier spacing △f = 2 u*15 kHz. The following table shows the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per for the normal CP, according to the subcarrier spacing △f = 2 u*15 kHz.
u N slot symb N frame,u slot N subframe,u slot
0 14 10 1
1 14 20 2
2 14 40 4
3 14 80 8
4 14 160 16
The following table shows the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per for the extended CP, according to the subcarrier spacing △f = 2 u*15 kHz.
u N slot symb N frame,u slot N subframe,u slot
2 12 40 4
A slot includes plural symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g. subcarrier spacing) and carrier, a resource grid of N size,u grid,x* N RB sc subcarriers and N subframe,u symb OFDM symbols is defined, starting at common resource block (CRB) N start,u grid indicated by higher-layer signaling (e.g. radio resource control (RRC) signaling), where N size,u grid,x is the number of resource blocks in the resource grid and the subscript x is DL for downlink and UL for uplink. N RB sc is the number of subcarriers per resource blocks. In the 3GPP based wireless communication system, N RB sc is 12 generally. There is one resource grid for a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL). The carrier bandwidth N size,u grid for subcarrier spacing configuration u is given by the higher-layer parameter (e.g. RRC parameter). Each element in the resource grid for the antenna port p and the subcarrier spacing configuration u is referred to as a resource element (RE) and one complex symbol may be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l representing a symbol location relative to a reference point in the time domain. In the 3GPP based wireless communication system, a resource block is defined by 12 consecutive subcarriers in the frequency domain.
In the 3GPP NR system, resource blocks are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with 'point A' which serves as a common reference point for resource block grids. In the 3GPP NR system, PRBs are defined within a bandwidth part (BWP) and numbered from 0 to N size BWP,i-1, where i is the number of the bandwidth part. The relation between the physical resource block n PRB in the bandwidth part i and the common resource block n CRB is as follows: n PRB = n CRB + N size BWP,i, where N size BWP,i is the common resource block where bandwidth part starts relative to CRB 0. The BWP includes a plurality of consecutive resource blocks. A carrier may include a maximum of N (e.g., 5) BWPs. A UE may be configured with one or more BWPs on a given component carrier. Only one BWP among BWPs configured to the UE can active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.
FIG. 6 illustrates a data flow example in the 3GPP NR system.
In FIG. 6, "RB" denotes a radio bearer, and "H" denotes a header. Radio bearers are categorized into two groups: data radio bearers (DRB) for user plane data and signalling radio bearers (SRB) for control plane data. The MAC PDU is transmitted/received using radio resources through the PHY layer to/from an external device. The MAC PDU arrives to the PHY layer in the form of a transport block.
In the PHY layer, the uplink transport channels UL-SCH and RACH are mapped to physical uplink shared channel (PUSCH) and physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to physical downlink shared channel (PDSCH), physical broad cast channel (PBCH) and PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to PUCCH, and downlink control information (DCI) is mapped to PDCCH. A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCH is transmitted by a BS via a PDSCH based on a DL assignment.
If a UE is powered on or newly enters a cell, the UE performs an initial cell search procedure of acquiring time and frequency synchronization with the cell and detecting a physical cell identity N cell ID of the cell. To this end, the UE may obtain (time and/or frequency) synchronization with a cell of the BS by receiving synchronization signals of the cell, e.g. a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), from the BS and obtain information such as a cell identity (ID). The UE having finished initial cell search may perform the random access procedure to complete access to the BS. To this end, the UE may transmit a preamble through a physical random access channel (PRACH), and receive a response message which is a response to the preamble through a PDCCH and PDSCH. In the case of contention-based random access, transmission of an additional PRACH and a contention resolution procedure for the PDCCH and a PDSCH corresponding to the PDCCH may be performed. After performing the procedure described above, the UE may perform PDCCH/PDSCH reception and PUSCH/PUCCH transmission as a typical procedure of transmission of an uplink/downlink signal.
The random access procedure is used for various purposes including initial access, adjustment of uplink synchronization, resource assignment, and handover. The random access procedure takes two distinct forms: a contention-based random access (CBRA) procedure and a contention-free random access (CFRA) procedure. The CFRA procedure is used for general operations including initial access, while the CFRA procedure is used for limited operations such as handover, random access triggered by PDCCH order, BFR, request for other SI and etc.
The CBRA procedure may include the following four steps. Messages/transmissions in Steps 1 to 4 given below may be referred to as Msg1 to Msg4, respectively.
1) Step 1: Random Access Preamble on RACH in uplink (Msg1 from UE to BS);
2) Step 2: Random Access Response on DL-SCH (Msg2 from BS to UE);
3) Step 3: First scheduled UL transmission on UL-SCH (Msg3 from UE to BS); and
4) Step 4: Contention Resolution on DL (Msg4 from BS to UE).
The CFRA procedure may include the following three steps.
1) Step 0: Random Access Preamble assignment (from BS to UE);
2) Step 1: Random Access Preamble on RACH in uplink (Msg1 from UE to BS); and
3) Step 2: Random Access Response on DL-SCH (Msg2 from BS to UE).
The random access procedure is initiated by a PDCCH order, by a MAC entity itself, or by RRC. There is only one random access procedure on-going at any point in time in a MAC entity. A random access procedure is triggered by various events. The events triggering the random access procedure may comprise: initial access from RRC_IDLE; RRC connection re-establishment; DL or UL data arrival during RRC_CONNECTED when UL synchronization status is "non-synchronized"; UL data arrival during RRC_CONNECTED when there is no PUCCH resources for scheduling request (SR) available; SR failure; request by RRC upon synchronization reconfiguration (e.g. handover); transition from RRC_INACTIVE; to establish time alignment at SCell addition; request for other system information (SI), where the other SI encompasses all system information blocks (SIBs) not broadcast in the minimum SI required for initial access and information for acquiring any other SI; and/or beam failure recovery.
The network configures the UE with the parameters for the Random Access procedure via RRC signaling. The parameters for the Random Access procedure may comprise:
- preambleReceivedTargetPower: initial Random Access Preamble power;
- ra-PreambleIndex: Random Access Preamble;
- preambleTransMax: the maximum number of Random Access Preamble transmission;
- ra-ResponseWindow: the time window to monitor RA response(s) (SpCell only);
- ra-ContentionResolutionTimer: the Contention Resolution Timer (SpCell only).
The following UE variables may be used for the Random Access procedure: PREAMBLE_INDEX; PREAMBLE_TRANSMISSION_COUNTER; PREAMBLE_POWER_RAMPING_COUNTER; PREAMBLE_POWER_RAMPING_STEP; PREAMBLE_RECEIVED_TARGET_POWER; PREAMBLE_BACKOFF; PCMAX; SCALING_FACTOR_BI; TEMPORARY_C-RNTI.
When a Random Access procedure is initiated on a serving cell, a MAC entity for the serving cell performs a Random Access Resource selection procedure to select a Random Access Preamble with a ra-PreambleIndex and a PRACH occasion, sets PREAMBLE_INDEX to the ra-PreambleIndex, and transmits the Random Access Preamble using the PRACH occasion. Once the Random Access Preamble is transmitted on the serving cell, the MAC entity monitors a PDCCH for a random access response(s) identified by an RA-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted (in case of CBRA procedure), or a PDCCH identified by the C-RNTI (in case of CFRA procedure), during a random access response window (e.g. while ra-ResponseWindow configured for the Random Access Procedure is running). For example, once the Random Access Preamble is transmitted on the serving cell, the MAC entity:
1> if the contention-free random access preamble for beam failure recovery request was transmitted by the MAC entity:
2>> starts the ra-ResponseWindow configured in BeamFailureRecoveryConfig (see 3GPP TS 38.331) at the first PDCCH occasion from the end of the Random Access Preamble transmission;
2>> monitors the PDCCH of the SpCell for response to beam failure recovery request identified by the C-RNTI while ra-ResponseWindow is running.
1> else:
2>> starts the ra-ResponseWindow configured in RACH-ConfigCommon (see 3GPP TS 38.331) at the first PDCCH occasion from the end of the Random Access Preamble transmission;
2>> monitors the PDCCH of the SpCell for Random Access Response(s) identified by the RA-RNTI while the ra-ResponseWindow is running.
1> if notification of a reception of a PDCCH transmission is received from lower layers (e.g. PHY); and
1> if PDCCH transmission is addressed to the C-RNTI; and
1> if the contention-free Random Access Preamble for beam failure recovery request was transmitted by the MAC entity:
2>> considers the Random Access procedure successfully completed.
1> else if a downlink assignment has been received on the PDCCH for the RA-RNTI and the received TB is successfully decoded:
2>> if the Random Access Response contains a MAC subPDU with Backoff Indicator:
3>>> sets the PREAMBLE_BACKOFF to value of the BI field of the MAC subPDU using Table 7.2-1 of 3GPP TS 38.321, multiplied with SCALING_FACTOR_BI.
2>> else:
3>>> sets the PREAMBLE_BACKOFF to 0 ms.
2>> if the Random Access Response contains a MAC subPDU with Random Access Preamble identifier (RAP ID) corresponding to the transmitted PREAMBLE_INDEX:
3>>> considers this Random Access Response reception successful.
2>> if the Random Access Response reception is considered successful:
3>>> if the Random Access Response includes a MAC subPDU with RAPID only:
4>>>> considers this Random Access procedure successfully completed;
3>>> else:
4>>>> if the Random Access Preamble was not selected by the MAC entity among the contention-based Random Access Preamble(s):
5>>>>> considers the Random Access procedure successfully completed.
4>>>> else:
5>>>>> sets the TEMPORARY_C-RNTI to the value received in the Random Access Response;
5>>>>> if this is the first successfully received Random Access Response within this Random Access procedure:
6>>>>>> if the transmission is not being made for the CCCH logical channel:
7>>>>>>> indicates to the multiplexing and assembly entity to include a C-RNTI MAC control element (CE) in the subsequent uplink transmission.
6>>>>>> obtains the MAC PDU to transmit from the multiplexing and assembly entity and store it in the Msg3 buffer.
1> if ra-ResponseWindow configured in RACH-ConfigCommon (see 3GPP TS 38.331) expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received; or
1> if ra-ResponseWindow configured in BeamFailureRecoveryConfig (see 3GPP TS 38.331) expires and if the PDCCH addressed to the C-RNTI has not been received:
2>> considers the Random Access Response reception not successful;
2>> increments PREAMBLE_TRANSMISSION_COUNTER by 1;
2>> if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:
3>>> if the Random Access Preamble is transmitted on the SpCell:
4>>>> indicates a Random Access problem to upper layers (e.g. RRC);
4>>>> if this Random Access procedure was triggered for SI request:
5>>>>> considers the Random Access procedure unsuccessfully completed.
3>>> else if the Random Access Preamble is transmitted on a SCell:
4>>>> considers the Random Access procedure unsuccessfully completed.
2>> if the Random Access procedure is not completed:
3>>> if in this Random Access procedure, the Random Access Preamble was selected by MAC among the contention-based Random Access Preambles:
4>>>> selects a random back-off time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;
4>>>> delays the subsequent Random Access Preamble transmission by the back-off time.
3>>> performs the Random Access Resource selection procedure.
The MAC entity may stop ra-ResponseWindow (and hence monitoring for Random Access Response(s)) after successful reception of a Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX. Contention Resolution is based on either C-RNTI on PDCCH of the SpCell or UE Contention Resolution Identity on DL-SCH. Once Msg3 is transmitted, the MAC entity:
1> starts the ra-ContentionResolutionTimer and restarts the ra-ContentionResolutionTimer at each HARQ retransmission in the first symbol after the end of the Msg3 transmission;
1> monitors the PDCCH while the ra-ContentionResolutionTimer is running regardless of the possible occurrence of a measurement gap;
1> if notification of a reception of a PDCCH transmission is received from lower layers:
2>> if the C-RNTI MAC CE was included in Msg3:
3>>> if the Random Access procedure was initiated by the MAC sublayer itself or by the RRC sublayer and the PDCCH transmission is addressed to the C-RNTI and contains a UL grant for a new transmission; or
3>>> if the Random Access procedure was initiated by a PDCCH order and the PDCCH transmission is addressed to the C-RNTI; or
3>>> if the Random Access procedure was initiated for beam failure recovery and the PDCCH transmission is addressed to the C-RNTI:
4>>>> considers this Contention Resolution successful;
4>>>> stops ra-ContentionResolutionTimer;
4>>>> considers this Random Access procedure successfully completed.
2>> else if the CCCH SDU was included in Msg3 and the PDCCH transmission is addressed to its TEMPORARY_C-RNTI:
3>>> if the MAC PDU is successfully decoded:
4>>>> stops ra-ContentionResolutionTimer;
4>>>> if the MAC PDU contains a UE Contention Resolution Identity MAC CE; and
4>>>> if the UE Contention Resolution Identity in the MAC CE matches the CCCH SDU transmitted in Msg3:
5>>>>> considers this Contention Resolution successful and finish the disassembly and demultiplexing of the MAC PDU;
5>>>>> else:
6>>>>>> set the C-RNTI to the value of the TEMPORARY_C-RNTI;
5>>>>> consider this Random Access procedure successfully completed.
4>>>> else
5>>>>> considers this Contention Resolution not successful and discard the successfully decoded MAC PDU.
1> if ra-ContentionResolutionTimer expires:
2>> considers the Contention Resolution not successful.
1> if the Contention Resolution is considered not successful:
2>> flushes the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer;
2>> increments PREAMBLE_TRANSMISSION_COUNTER by 1;
2>> if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:
3>>> indicates a Random Access problem to upper layers.
3>>> if this Random Access procedure was triggered for SI request:
4>>>> considers the Random Access procedure unsuccessfully completed.
2>> if the Random Access procedure is not completed:
3>>> selects a random back-off time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;
3>>> delays the subsequent Random Access Preamble transmission by the back-off time;
3>>> performs the Random Access Resource selection procedure
Upon completion of the Random Access procedure, the MAC entity flushes the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer.
In order to transmit data on UL-SCH, a UE shall have uplink resources available to the UE. In order to receive data on DL-SCH, a UE shall have downlink resources available to the UE. The resource allocation includes time domain resource allocation and frequency domain resource allocation. In the present disclosure, uplink resource allocation is also referred to as uplink grant, and downlink resource allocation is also referred to as downlink assignment. An uplink grant is either received by the UE dynamically on PDCCH, in a Random Access Response, or configured to the UE semi-persistently by RRC. Downlink assignment is either received by the UE dynamically on the PDCCH, or configured to the UE semi-persistently by RRC signaling from the BS. In particular, a UL grant that is configured semi-persistently and DL assignment that is configured semi-persistently are referred to as a configured UL grant and a configured DL assignment, respectively.
In NR, for uplink, there are two types of transmission without dynamic grant: configured grant Type 1 where an uplink grant is provided by RRC, and stored as configured grant; and configured grant Type 2 where an uplink grant is provided by PDCCH, and stored or cleared as configured uplink grant based on L1 signaling indicating configured uplink grant activation or deactivation. Type 1 and Type 2 are configured by RRC per serving cell and per BWP. Multiple configurations can be active simultaneously only on different serving cells. For Type 2, activation and deactivation are independent among the serving cells. For the same serving cell, the MAC entity is configured with either Type 1 or Type 2.
A UE is provided with at least the following parameters via RRC signaling from a BS when the configured grant type 1 is configured:
- cs-RNTI which is CS-RNTI for retransmission;
- periodicity which provides periodicity of the configured grant Type 1;
- timeDomainOffset which represents offset of a resource with respect to SFN=0 in time domain;
- timeDomainAllocation value m which provides a row index m+1 pointing to an allocation table, indicating a combination of a start symbol S and length L and PUSCH mapping type;
- frequencyDomainAllocation which provides frequency domain resource allocation; and
- mcsAndTBS which provides I MCS representing the modulation order, target code rate and transport block size. Upon configuration of a configured grant Type 1 for a serving cell by RRC, the UE stores the uplink grant provided by RRC as a configured uplink grant for the indicated serving cell, and initialise or re-initialise the configured uplink grant to start in the symbol according to timeDomainOffset and S (derived from SLIV), and to reoccur with periodicity. After an uplink grant is configured for a configured grant Type 1, the UE considers that the uplink grant recurs associated with each symbol for which: [(SFN * numberOfSlotsPerFrame ( numberOfSymbolsPerSlot) + (slot number in the frame Х numberOfSymbolsPerSlot) + symbol number in the slot] = ( timeDomainOffset * numberOfSymbolsPerSlot + S + N * periodicity) modulo (1024 * numberOfSlotsPerFrame * numberOfSymbolsPerSlot), for all N >= 0.
A UE is provided with at least the following parameters via RRC signaling from a BS when the configured gran Type 2 is configured:
- cs-RNTI which is CS-RNTI for activation, deactivation, and retransmission; and
- periodicity which provides periodicity of the configured grant Type 2. The actual uplink grant is provided to the UE by the PDCCH (addressed to CS-RNTI). After an uplink grant is configured for a configured grant Type 2, the UE considers that the uplink grant recurs associated with each symbol for which: [(SFN * numberOfSlotsPerFrame * numberOfSymbolsPerSlot) + (slot number in the frame * numberOfSymbolsPerSlot) + symbol number in the slot] = [(SFN start time * numberOfSlotsPerFrame * numberOfSymbolsPerSlot + slot start time * numberOfSymbolsPerSlot + symbol start time) + N * periodicity] modulo (1024 Х numberOfSlotsPerFrame * numberOfSymbolsPerSlot), for all N >= 0, where SFN start time, slot start time, and symbol start time are the SFN, slot, and symbol, respectively, of the first transmission opportunity of PUSCH where the configured uplink grant was (re-)initialised. numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive OFDM symbols per slot, respectively (see Table 1 and Table 2).
For configured uplink grants, the HARQ Process ID associated with the first symbol of a UL transmission is derived from the following equation:
HARQ Process ID = [floor(CURRENT_symbol/ periodicity)] modulo nrofHARQ-Processes,
where CURRENT_symbol = (SFN Х numberOfSlotsPerFrame Х numberOfSymbolsPerSlot + slot number in the frame Х numberOfSymbolsPerSlot + symbol number in the slot), and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively as specified in TS 38.211. CURRENT_symbol refers to the symbol index of the first transmission occasion of a repetition bundle that takes place. A HARQ process is configured for a configured uplink grant if the configured uplink grant is activated and the associated HARQ process ID is less than nrofHARQ-Processes.
For configured uplink grant(s), configuredGrantTimer may be configured to a UE by a network.
Hybrid automatic retransmission request (HARQ) is a method used for error control. HARQ-acknowledgement (ACK) transmitted on DL is used for error control regarding UL data and HARQ-ACK transmitted on UL is used for error control regarding DL data. On DL, a BS schedules one or more resource blocks for a UE selected according to a predetermined scheduling rule and transmits data to the UE using the scheduled resource blocks. On UL, the BS schedules one or more resource blocks for a UE selected according to a predetermined scheduling rule and the UE transmits data using allocated resources on UL. A transmitting device performing a HARQ operation waits for an ACK signal after transmitting data (e.g., transport block, codeword). A receiving device performing the HARQ operation transmits the ACK signal only when the data has been correctly received and transmits a negative-ACK (NACK) signal when there is an error in the received data. Upon receiving the ACK signal, the transmitting device transmits subsequent (new) data while, upon receiving the NACK signal, the transmitting device retransmits data. In a HARQ scheme, error data is stored in a HARQ buffer and initial data is combined with subsequent retransmission data in order to raise reception success rate. The HARQ scheme is categorized as synchronous HARQ and asynchronous HARQ according to retransmission timing and as adaptive HARQ and non-adaptive HARQ depending on whether a channel state is considered during determination of retransmission resources. In the synchronous HARQ scheme, when initial transmission fails, retransmission is performed at a timing determined by a system. For example, if it is assumed that retransmission is performed in every X-th (e.g. X=4) time unit (e.g. TTI, subframe, slot, symbol) after initial transmission fails, the eNB and the UE do not need to exchange information about a retransmission timing. Therefore, upon receiving a NACK message, the transmitting device may retransmit corresponding data in every fourth time unit until an ACK message is received. In contrast, in the asynchronous HARQ scheme, the retransmission timing is determined by new scheduling or additional signaling. That is, the retransmission timing for error data may be changed by various factors such as channel state. In the non-adaptive HARQ scheme, a modulation and coding scheme (MCS), the number of resource blocks, etc., which are needed for retransmission, are determined as those during initial transmission. In contrast, in the adaptive HARQ scheme, the MCS, the number of resource blocks, etc. for retransmission are changed according to channel state. For example, in the non-adaptive HARQ scheme, when initial transmission is performed using 6 resource blocks, retransmission is also performed using 6 resource blocks. In contrast, in the non-adaptive HARQ scheme, even when initial transmission is performed using 6 resource blocks, retransmission may be performed using resource blocks less or greater in number than 6 according to channel state. Based on such classification, a combination of the four HARQ schemes may be considered but an asynchronous adaptive HARQ scheme and a synchronous non-adaptive HARQ scheme are mainly used. In the asynchronous adaptive HARQ scheme, the retransmission timing and retransmitted resources are adaptively changed according to channel state so as to maximize retransmission efficiency. However, overhead is increased. Meanwhile, in the synchronous non-adaptive HARQ scheme, since the retransmission timing and retransmission resource allocation are determined by the system, almost no overhead occurs but retransmission efficiency is very low if this scheme is used in an environment in which the channel state is considerably changed.
Meanwhile, a time delay occurs until the BS receives HARQ-ACK from the UE and transmits retransmission data after transmitting scheduling information and data according to the scheduling information. The time delay occurs due to a channel propagation delay or a time consumed for data decoding/encoding. Accordingly, if new data is transmitted after a HARQ process which is currently in progress is ended, a gap in data transmission occurs due to a time delay. In order to prevent a gap in data transmission from occurring during a time delay duration, a plurality of independent HARQ processes is used. For example, when an interval between initial transmission and retransmission is 7 time units, 7 independent HARQ processes may be performed to transmit data without a gap. A plurality of parallel HARQ processes enables successive UL/DL transmission while the BS awaits HARQ feedback for previous UL/DL transmission. Each HARQ process is associated with a HARQ buffer of a MAC layer. Each HARQ process manages state variables regarding the number of transmissions of a MAC PDU in the buffer, HARQ feedback for the MAC PDU in the buffer, a current redundancy version, etc.
To perform the requested transmissions, the MAC layer receives HARQ information from lower layers (e.g. PHY). HARQ information may include New Data Indicator (NDI), Transport Block size (TBS), Redundancy Version (RV), and HARQ process identifier (ID). A MAC entity includes a HARQ entity for each serving cell with configured uplink, which maintains a number of parallel HARQ processes. Each HARQ process supports one transport block. Each HARQ process is associated with a HARQ process ID. For each uplink grant, a HARQ entity of a MAC entity shall:
1> identify the HARQ process associated with this grant, and for each identified HARQ process:
2>> if the received grant was not addressed to a Temporary C-RNTI on PDCCH, and the new data indicator (NDI) provided in the associated HARQ information has been toggled compared to the value in the previous transmission of this transport block (TB) of this HARQ process; or
2>> if the uplink grant was received on PDCCH for the C-RNTI and the HARQ buffer of the identified process is empty; or
2>> if the uplink grant was received in a Random Access Response; or
2>> if the uplink grant is part of a bundle of the configured uplink grant, and may be used for initial transmission, and if no MAC PDU has been obtained for this bundle:
3>>> if there is a MAC PDU in the Msg3 buffer and the uplink grant was received in a Random Access Response:
4>>>> obtain the MAC PDU to transmit from the Msg3 buffer.
3>>> else:
4>>>> obtain the MAC PDU to transmit from the multiplexing and assembly entity, if any;
3>>> if a MAC PDU to transmit has been obtained:
4>>>> deliver the MAC PDU and the uplink grant and the HARQ information of the TB to the identified HARQ process;
4>>>> instruct the identified HARQ process to trigger a new transmission;
4>>>> if the uplink grant is addressed to CS-RNTI; or
4>>>> if the uplink grant is a configured uplink grant; or
4>>>> if the uplink grant is addressed to C-RNTI, and the identified HARQ process is configured for a configured uplink grant:
5>>>>> start or restart the configuredGrantTimer, if configured, for the corresponding HARQ process when the transmission is performed.
3>>> else:
4>>>> flush the HARQ buffer of the identified HARQ process.
2>> else (i.e. retransmission):
3>>> if the uplink grant received on PDCCH was addressed to CS-RNTI and if the HARQ buffer of the identified process is empty; or
3>>> if the uplink grant is part of a bundle and if no MAC PDU has been obtained for this bundle; or
3>>> if the uplink grant is part of a bundle of the configured uplink grant, and the PUSCH of the uplink grant overlaps with a PUSCH of another uplink grant received on the PDCCH for this Serving Cell:
4>>>> ignore the uplink grant.
3>>> else:
4>>>> deliver the uplink grant and the HARQ information (redundancy version) of the TB to the identified HARQ process;
4>>>> instruct the identified HARQ process to trigger a retransmission;
4>>>> if the uplink grant is addressed to CS-RNTI; or
4>>>> if the uplink grant is addressed to C-RNTI, and the identified HARQ process is configured for a configured uplink grant:
5>>>>> start or restart the configuredGrantTimer, if configured, for the corresponding HARQ process when the transmission is performed.
New transmissions are performed on the resource and with the modulation and coding scheme (MCS) indicated on either PDCCH, Random Access Response, or RRC. Retransmissions are performed on the resource and, if provided, with the MCS indicated on PDCCH, or on the same resource and with the same MCS as was used for last made transmission attempt within a bundle. If the HARQ entity requests a new transmission for a TB, the HARQ process shall:
1> store the MAC PDU in the associated HARQ buffer;
1> store the uplink grant received from the HARQ entity;
1> generate a transmission as described below.
If the HARQ entity requests a retransmission for a TB, the HARQ process shall:
1> store the uplink grant received from the HARQ entity;
1> generate a transmission as described below.
To generate a transmission for a TB, the HARQ process shall:
1> if the MAC PDU was obtained from the Msg3 buffer; or
1> if there is no measurement gap at the time of the transmission and, in case of retransmission, the retransmission does not collide with a transmission for a MAC PDU obtained from the Msg3 buffer:
2>> instruct the physical layer to generate a transmission according to the stored uplink grant.
Msg3 is a message transmitted on UL-SCH containing a C-RNTI MAC CE or CCCH SDU, submitted from upper layer and associated with the UE Contention Resolution Identity, as part of a Random Access procedure.
FIG. 7 illustrates an example showing a case where UE cannot perform retransmission for PDU via a configured grant during the random access procedure.
In NR, it is possible for a UE configured with configured grant to perform a random access procedure (e.g. for beam failure recovery, or when the number of SR transmissions reaches sr-TransMax configured by the network). In the NR communication standards, it has been regulated that, for UL transmission with UL grant in Random Access Response, HARQ process ID 0 is used.
If there is a configured resource for the HARQ process ID 0 between Random Access Preamble transmission and Random Access Response reception, as shown in FIG. 7, the PDU A transmitted via the configured resource will be overwritten by PDU B for Msg3 transmission. As the UE replaces the PDU A transmitted via the configured resource in the HARQ buffer of HARQ process ID 0 by the PDU B for Msg3 transmission, the UE cannot perform retransmission for the PDU A transmitted via the configured resource. Moreover, as the network has not yet identified the UE, the network may order retransmission of the PDU A stored in HARQ process ID 0. In this case, as the UE already replace the PDU A in the HARQ process ID 0 by the PDU B for Msg3, the network would fail at decoding.
Besides, if the UE performs new transmission using configured grant associated with HARQ PID 0 after the Msg3 is transmitted, the UE will replace the PDU for Msg3 by the PDU transmitted via configured grant prior to completion of the Random Access procedure. Therefore, the UE may not successfully complete the Random Access procedure as the UE may not perform retransmission of the Msg3.
Accordingly, HARQ process ID collision should be avoided through the whole random access procedure.
As a method for ensuring that the random access procedure is performed without being interrupted by a configured grant and that transmissions via configured grants have enough retransmission opportunities, one might consider relying on the UE implementation. However, as a HARQ process ID for each configured grant (CG) is pre-defined between the UE and the network, the UE cannot change a HARQ process ID for the CG by itself. Besides, it is not allowed for a UE to use another HARQ ID for Msg3 transmission as it is regulated in the communication standards that HARQ process ID 0 is used for UL transmission with UL grant in Random Access Response. If the UE uses another HARQ process ID for Msg3 transmission or CG by itself, the network is not be able to order retransmission because it does not know which HARQ process ID is used in the UE side, which would cause more significant problem in the system.
As another method, one might consider splitting the HARQ PID for Msg3 transmission and CG so that HARQ process ID collision never happens. For example, changing a HARQ process ID from 0 to N for the Msg3 transmission might be considered. For another example, shifting the HARQ process ID by 1 for CG. However, these options may have an impact on PHY and RRC as well as MAC since the range of HARQ process IDs should change from [0, N-1] to [0, N].
As still another method, one might consider a timer based approach. For example, the UE starts or restarts configuredGrantTimer for the corresponding HARQ process ID 0 upon reception of an uplink grant in a random access response or transmission of Msg3. However, starting configuredGrantTimer may not be sufficient if the length of configuredGrantTimer is not long enough to cover the whole random access procedure.
As an alternative of the timer based approach, one might consider using a contention resolution timer to prevent use of HARQ process ID 0 after Msg3 transmission or to specify the duration from Msg3 to Msg4 without a timer where HARQ process ID 0 is not to be used. However, this solution cannot prevent the HARQ process ID collision from occurring during the whole random access procedure.
The present disclosure proposes the following solution in order to ensure that a random access procedure is performed without being interrupted by a configured grant throughout the whole random access procedure and that transmission (Tx) via a configured grant has enough retransmission opportunities even when the transmission is performed during a random access procedure.
FIG. 8 illustrates an example of a flow diagram for UL transmission according to an implementation of the present disclosure.
In the present disclosure, the UE configured with a configured grant skips uplink transmission on the configured grant during a random access procedure (S803) if the configured grant is associated with a HARQ process that is to be used for an Msg3 transmission and of the configured grant occurs after initiating a random access procedure (S801, Yes).
For example, when the configured grant occurs after initiating the random access procedure, the UE is allowed to perform uplink transmission on the configured grant (S805) only if the configured grant is associated with a HARQ process that is not to be used for the Msg3 transmission (S801, No). In the following description, it is assumed that a HARQ process having HARQ process ID 0 is used for the Msg3 transmission.
In the present disclosure, skipping uplink transmission on a configured grant may comprise generating no MAC PDU for the configured grant even if there is uplink data to be transmitted and/or not transmitting, via the configured grant, a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
In implementations of the present disclosure, the random access procedure may be CBRA or CFRA procedure. After a CFRA procedure is initiated, the UE may switch to a CBRA procedure according to the conditions specified in MAC specification (see 3GPP TS 38.321, for example).
During a random access procedure, a UE of the present disclosure skips uplink transmission on a configured grant if the configured grant is associated with a HARQ process that is to be used for Msg3 transmission and the configured grant occurs between Time Point 1 and Time Point 2. In the present disclosure, Time Point 1 may be one of the followings: initiation of a random access procedure; or selection of a random access resource; or transmission of a random access preamble. In the present disclosure, Time Point 2 may be one of the followings: upon successful transmission of an Msg3; or upon successful reception of an Msg4; or upon completion of the random access procedure, which can be either successful or unsuccessful.
In the present disclosure, the UE skips uplink transmission on a configured grant which is associated with a HARQ process ID used for Msg3 transmission and occurs between Time Point 1 and Time Point 2, even if there is uplink data to be transmitted in the UE side. In particular, for a configured grant which is associated with a HARQ process ID used for Msg3 transmission and occurs between Time Point 1 and Time Point 2, the UE does not generate a MAC PDU even if there is uplink data to be transmitted. Alternatively, for a configured grant which is associated with a HARQ process ID used for Msg3 transmission and occurs between Time Point 1 and Time Point 2, the UE does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
During a random access procedure, a UE is allowed to perform uplink transmission on a configured grant if the configured grant is not associated with a HARQ process which is to be used for a Msg3 transmission; or if the configured grant is associated with a HARQ process which is to be used for a Msg3 transmission but the configured grant occurs out of Time Point 1 and Time Point 2. The UE may perform uplink transmission only when there is uplink data to be transmitted.
In order to prohibit uplink transmission on a configured grant between Time Point 1 and Time Point 2, a UE can operate a timer, for instance, configuredGrantTimer. In specific, the UE starts/restarts the timer for a HARQ process which is to be used for the Msg3 transmission when the UE initiates a random access procedure, and/or when the UE selects a random access resource, and/or the UE transmits a random access preamble. While the timer is running, the UE skips uplink transmission on a configured grant associated with a HARQ process (e.g., HARQ process ID 0) which is used for the Msg3 transmission.
FIG. 9 illustrates examples of UL transmission on a configured grant considering a random access procedure according to the implementations of the present disclosure. In the examples of FIG. 9, the UE is configured with configured grant by a network. The UE generates configured grants. For example, the UE determines the HARQ process ID associated with the configured grant.
Referring to FIG. 9(a), after a random access procedure is initiated, the UE transmits a Random Access Preamble (i.e., Msg1) at T1. At T2, T3 and T4, when there is a configured grant associated with the HARQ process ID 0 (HP ID 0) that is used for an Msg3 transmission during the random access procedure (e.g., while the random access procedure is on-going, i.e., while there is an on-going random access procedure), the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant. At T5, when there is a configured grant associated with the HP ID 0 that is used for an Msg3 transmission out of a random access procedure (e.g., while the random access procedure is not on-going, i.e., while there is no on-going random access procedure), the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits, via the configured grant, a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
Referring to FIG. 9(b), after a random access procedure is initiated, the UE transmits a Random Access Preamble (i.e., Msg1) at T1. At T2 and T4, when there is a configured grant associated with the HP ID 0 that is used for an Msg3 transmission during the random access procedure (e.g., while the random access procedure is on-going), the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant. At T3, when there is a configured grant associated with the HP ID 1 that is not used for a Msg3 transmission during the random access procedure, the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant. At T5, after completion of the random access procedure, when there is a configured grant associated with the HP ID 1 out of a random access procedure (e.g., while the random access procedure is not on-going), the UE transmits the UL data using the configured grant. At T6, after completion of the random access procedure, when there is a configured grant associated with the HP ID 0 out of a random access procedure, the UE transmits the UL data using the configured grant.
In the examples of FIG. 9, the UL transmission on the configured grant may be skipped irrespective of whether a configured grant timer for the HARQ process used for an Msg3 transmission is running.
FIG. 10 illustrates an example of UL transmission on a configured grant considering a random access procedure and a timer according to an implementation of the present disclosure. In the example of FIG. 10, the UE is configured with configured grant by a network. The UE generates configured grants. For example, the UE determines the HARQ process ID associated with the configured grant.
Once UE transmits a contention-based Random Access Preamble (Msg1) at T1, the UE starts a timer for a HARQ process which is to be used for the Msg3 transmission. At T2, T3 and T4, when there is a configured grant associated with the HP ID 0 which is to be used for the Msg3 transmission while the timer is running, the UE does not generate a MAC PDU even if there is uplink data to be transmitted, or does not transmit a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant. At T5, when there is a configured grant associated with the HP ID 0 which is to be used for the Msg3 transmission while the timer is not running, the UE generates a MAC PDU if there is uplink data to be transmitted and transmits the generated MAC PDU via the configured grant, or transmits a MAC PDU stored in the HARQ buffer of the HARQ process associated with the configured grant.
According to the implementations of the present disclosure, the random access procedure can be performed without being interrupted by a configured grant throughout the whole random access procedure, and transmission via a configured grant can have enough retransmission chances even when the transmission is performed during a random access procedure.
As described above, the detailed description of the preferred implementations of the present disclosure has been given to enable those skilled in the art to implement and practice the disclosure. Although the disclosure has been described with reference to exemplary implementations, those skilled in the art will appreciate that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosure described in the appended claims. Accordingly, the disclosure should not be limited to the specific implementations described herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein.
The implementations of the present disclosure are applicable to a network node (e.g., BS), a UE, or other devices in a wireless communication system.

Claims (15)

  1. A method for transmitting uplink signals by a user equipment in a wireless communication system, the method comprising:
    determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure;
    skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and
    performing the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process.
  2. The method according to claim 1, further comprising:
    starting a configured grant timer for the HARQ process when transmitting a random access preamble (Msg1) of the random access procedure.
  3. The method according to claim 1, wherein skipping the uplink transmission on the first configured grant comprises:
    generating no MAC PDU for the first configured grant.
  4. The method according to claim 1, wherein skipping the uplink transmission on the first configured grant comprises:
    skipping transmitting a MAC PDU stored in a HARQ buffer of the HARQ process associated with the first configured grant.
  5. The method according to claim 1, further comprising:
    performing uplink transmission on a second configured grant,
    wherein the second configured grant occurs while the random access procedure is not on-going.
  6. The method according to claim 1, wherein skipping the uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process comprises:
    skipping the uplink transmission on the first configured grant irrespective of whether a configured grant timer for the HARQ process is running.
  7. The method according to claim 1, wherein the first configured grant comprises a configured grant occurring after transmission of a random access preamble of the random access procedure and before completion of the random access procedure.
  8. A device for a user equipment of transmitting uplink signals in a wireless communication system, the device comprising:
    at least one processor; and
    at least one computer memory that is operably connectable to the at least one processor and that has stored thereon instructions which, when executed, cause the at least one processor to perform operations comprising:
    determining whether a first configured grant occurring while a random access procedure is on-going is associated with a hybrid automatic retransmission request (HARQ) process used for a Msg3 transmission of the random access procedure;
    skipping uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process; and
    performing, via a transceiver of the user equipment, the uplink transmission on the first configured grant when the first configured grant is not associated with the HARQ process.
  9. The device according to claim 8, wherein the operations further comprise:
    starting a configured grant timer for the HARQ process when transmitting a random access preamble (Msg1) of the random access procedure.
  10. The device according to claim 8, wherein skipping the uplink transmission on the first configured grant comprises:
    generating no MAC PDU for the first configured grant.
  11. The device according to claim 8, wherein skipping the uplink transmission on the first configured grant comprises:
    skipping transmitting a MAC PDU stored in a HARQ buffer of the HARQ process associated with the first configured grant.
  12. The device according to claim 8, wherein the operations further comprise:
    performing, via the transceiver of the user equipment, uplink transmission on a second configured grant,
    wherein the second configured grant occurs while the random access procedure is not on-going.
  13. The device according to claim 8,
    wherein skipping the uplink transmission on the first configured grant when the first configured grant is associated with the HARQ process comprises:
    skipping the uplink transmission on the first configured grant irrespective of whether a configured grant timer for the HARQ process is running.
  14. The device according to claim 8,
    wherein the first configured grant comprises a configured grant occurring after transmission of a random access preamble of the random access procedure and before completion of the random access procedure.
  15. The device according to claim 8,
    wherein the user equipment is an autonomous vehicle that communicates with at least a mobile terminal, a network, and another autonomous vehicle other than the user equipment.
PCT/KR2019/009779 2018-08-08 2019-08-06 Method of transmitting uplink signals, and device therefor WO2020032530A1 (en)

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