WO2022061652A1 - Retransmission rapide d'une demande de session d'unité de données de protocole - Google Patents

Retransmission rapide d'une demande de session d'unité de données de protocole Download PDF

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Publication number
WO2022061652A1
WO2022061652A1 PCT/CN2020/117453 CN2020117453W WO2022061652A1 WO 2022061652 A1 WO2022061652 A1 WO 2022061652A1 CN 2020117453 W CN2020117453 W CN 2020117453W WO 2022061652 A1 WO2022061652 A1 WO 2022061652A1
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WIPO (PCT)
Prior art keywords
pdu session
session request
state
request
response
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PCT/CN2020/117453
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English (en)
Inventor
Hao Zhang
Tianya LIN
Jian Li
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Qualcomm Incorporated
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Publication date
Application filed by Qualcomm Incorporated filed Critical Qualcomm Incorporated
Priority to PCT/CN2020/117453 priority Critical patent/WO2022061652A1/fr
Publication of WO2022061652A1 publication Critical patent/WO2022061652A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/12—Setup of transport tunnels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H04W76/27—Transitions between radio resource control [RRC] states
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H04W76/22—Manipulation of transport tunnels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/30—Connection release

Definitions

  • the present disclosure relates generally to communication systems, and more particularly, to a fast resend of a protocol data unit (PDU) session request, such as when a user equipment (UE) is in a wrong state.
  • PDU protocol data unit
  • Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts.
  • Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • 5G New Radio is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements.
  • 3GPP Third Generation Partnership Project
  • 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communications (URLLC) .
  • eMBB enhanced mobile broadband
  • mMTC massive machine type communications
  • URLLC ultra-reliable low latency communications
  • Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard.
  • Wireless communication may involve the transmission of protocol data unit (PDU) session requests that may fail due to a lower-level protocol layer being in a wrong state. Improvements are presented herein. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
  • PDU protocol data unit
  • An example implementation includes a method of wireless communication to be performed by a user equipment (UE) , comprising generating a protocol data unit (PDU) session request.
  • the method further includes determining that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state. Additionally, the method further includes identifying a state change indicating that the UE is in a correct state. Additionally, the method further includes transmitting the PDU session request in response to identifying the state change.
  • PDU protocol data unit
  • Another example implementation includes an apparatus for wireless communication to be performed by a user equipment (UE) , comprising a memory and a processor communicatively coupled with the memory.
  • the processor is configured to generate a protocol data unit (PDU) session request.
  • the processor is further configured to determine that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state. Additionally, the processor further configured to identify a state change indicating that the UE is in a correct state. Additionally, the processor further configured to transmit the PDU session request in response to identifying the state change.
  • PDU protocol data unit
  • Another example implementation includes an apparatus for wireless communication to be performed by a user equipment (UE) , comprising means for generating a protocol data unit (PDU) session request.
  • the apparatus further includes means for determining that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state. Additionally, the apparatus further includes means for identifying a state change indicating that the UE is in a correct state. Additionally, the apparatus further includes means for transmitting the PDU session request in response to identifying the state change.
  • PDU protocol data unit
  • Another example implementation includes a computer-readable medium comprising stored instructions for wireless communication to be performed by a user equipment (UE) , executable by a processor to generate a protocol data unit (PDU) session request.
  • the instructions are further executable to determine that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state. Additionally, the instructions are further executable to identify a state change indicating that the UE is in a correct state. Additionally, the instructions are further executable to transmit the PDU session request in response to identifying the state change.
  • UE user equipment
  • PDU protocol data unit
  • the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims.
  • the following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.
  • FIG. 2A is a diagram illustrating an example of a first frame, in accordance with various aspects of the present disclosure.
  • FIG. 2B is a diagram illustrating an example of DL channels within a subframe, in accordance with various aspects of the present disclosure.
  • FIG. 2C is a diagram illustrating an example of a second frame, in accordance with various aspects of the present disclosure.
  • FIG. 2D is a diagram illustrating an example of UL channels within a subframe, in accordance with various aspects of the present disclosure.
  • FIG. 3 is a diagram illustrating an example of hardware components of the base station and the user equipment (UE) in the access network.
  • FIG. 4 is a call flow diagram illustrating communications between a UE and a base station in accordance with various aspects of the present disclosure.
  • FIG. 5 is a diagram illustrating an example UE in accordance with various aspects of the present disclosure.
  • FIG. 6 is a flowchart of a method of wireless communication to be performed by a UE in accordance with various aspects of the present disclosure.
  • FIG. 7 is a flowchart of additional or optional steps for a method of wireless communication to be performed by a UE in accordance with various aspects of the present disclosure.
  • FIG. 8 is a flowchart of additional or optional steps for a method of wireless communication to be performed by a UE in accordance with various aspects of the present disclosure.
  • FIG. 9 is a flowchart of additional or optional steps for a method of wireless communication to be performed by a UE in accordance with various aspects of the present disclosure.
  • FIG. 10 is a flowchart of additional or optional steps for a method of wireless communication to be performed by a UE in accordance with various aspects of the present disclosure.
  • a user equipment (UE) in a wireless communications system may determine that a protocol data unit (PDU) session request needs to be sent to a base station.
  • a current state of a lower-level protocol layer e.g., at a radio resource control (RRC) layer or at a non-access stratum (NAS) layer
  • RRC radio resource control
  • NAS non-access stratum
  • the UE may be configured to initiate a retransmission timer having a fixed duration (e.g., 16 seconds) for retransmitting the PDU session request based on a determination that the current state of the lower-level protocol layer may not support transmitting the PDU session request.
  • the retransmission timer duration may be longer than an amount of time needed for the lower-level protocol layer state to change into a state that may allow for transmission of the PDU session request.
  • increased latency may be introduced as a result of the fixed retransmission timer duration.
  • user experience may be negatively affected as a result.
  • aspects presented herein provide for transmission of the PDU session request based on an indication that the state of the lower-level protocol layer has changed into a state that may allow for transmission of the PDU session request.
  • the UE may not transmit the PDU session request to the base station when the lower-level protocol layer state is in a wrong state, however the lower-level protocol layer state may change into a correct state prior to expiration of the fixed retransmission timer duration.
  • Some aspects presented herein enable the UE to transmit the PDU session request while the retransmission timer is still running. Thus, aspects presented herein may reduce an amount of latency introduced by retransmission of the PDU session request and may improve user experience.
  • processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure.
  • processors in the processing system may execute software.
  • Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer.
  • such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • optical disk storage magnetic disk storage
  • magnetic disk storage other magnetic storage devices
  • combinations of the aforementioned types of computer-readable media or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100.
  • the wireless communications system also referred to as a wireless wide area network (WWAN)
  • WWAN wireless wide area network
  • EPC Evolved Packet Core
  • 5GC 5G Core
  • the UE 104 may be configured to communicate with the core network 190 to establish, modify, or release PDU sessions for exchanging data units (e.g., Internet protocol (IP) packets, Ethernet data frames, unstructured data, and the like) between the UE 104 and the access network 100.
  • data units e.g., Internet protocol (IP) packets, Ethernet data frames, unstructured data, and the like
  • the core network 190 may exchange signaling messages with the UE 104 and the base station 102 to perform PDU session management functions, such as establishment, modification, and release.
  • the UE 104 may include a fast resend component 198 configured to generate a PDU session request, determine that the PDU session request is not to be transmitted by the UE based at least on a determination that a lower-level protocol layer of the UE is in a wrong state, and transmit the PDU session request in response to identifying that the lower-level protocol layer of the UE is in a correct state.
  • the fast resend component may transmit the PDU session request prior to the expiration of a retransmission timer that was started in response to generating the PDU session request.
  • the base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) .
  • the macrocells include base stations.
  • the small cells include femtocells, picocells, and microcells.
  • the base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., S1 interface) .
  • the base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through second backhaul links 184.
  • NG-RAN Next Generation RAN
  • the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages.
  • NAS non-access stratum
  • RAN radio access network
  • MBMS multimedia broadcast multicast service
  • RIM RAN information management
  • the base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface) .
  • the first backhaul links 132, the second backhaul links 184, and the third backhaul links 134 may be wired or wireless.
  • the base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102.
  • a network that includes both small cell and macrocells may be known as a heterogeneous network.
  • a heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) .
  • eNBs Home Evolved Node Bs
  • HeNBs Home Evolved Node Bs
  • CSG closed subscriber group
  • the communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104.
  • the communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity.
  • the communication links may be through one or more carriers.
  • the base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc.
  • the component carriers may include a primary component carrier and one or more secondary component carriers.
  • a primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .
  • D2D communication link 158 may use the DL/UL WWAN spectrum.
  • the D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • sidelink channels such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) .
  • D2D communication may be through a variety of wireless D2D communications systems, such as for example, WiMedia, Bluetooth, ZigBe
  • the wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154, e.g., in a 5 GHz unlicensed frequency spectrum or the like.
  • AP Wi-Fi access point
  • STAs Wi-Fi stations
  • communication links 154 e.g., in a 5 GHz unlicensed frequency spectrum or the like.
  • the STAs 152/AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.
  • CCA clear channel assessment
  • the small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same unlicensed frequency spectrum (e.g., 5 GHz, or the like) as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.
  • the small cell 102' employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.
  • the electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc.
  • two initial operating bands have been identified as frequency range designations FR1 (410 MHz –7.125 GHz) and FR2 (24.25 GHz –52.6 GHz) .
  • the frequencies between FR1 and FR2 are often referred to as mid-band frequencies.
  • FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles.
  • FR2 which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz –300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.
  • EHF extremely high frequency
  • ITU International Telecommunications Union
  • sub-6 GHz or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies.
  • millimeter wave or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band.
  • a base station 102 may include and/or be referred to as an eNB, gNodeB (gNB) , or another type of base station.
  • Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave frequencies, and/or near millimeter wave frequencies in communication with the UE 104.
  • the gNB 180 may be referred to as a millimeter wave base station.
  • the millimeter wave base station 180 may utilize beamforming 182 with the UE 104 to compensate for the path loss and short range.
  • the base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.
  • the base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'.
  • the UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182”.
  • the UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions.
  • the base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions.
  • the base station 180/UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180/UE 104.
  • the transmit and receive directions for the base station 180 may or may not be the same.
  • the transmit and receive directions for the UE 104 may or may not be the same.
  • the EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172.
  • MME Mobility Management Entity
  • MBMS Multimedia Broadcast Multicast Service
  • BM-SC Broadcast Multicast Service Center
  • PDN Packet Data Network
  • the MME 162 may be in communication with a Home Subscriber Server (HSS) 174.
  • HSS Home Subscriber Server
  • the MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160.
  • the MME 162 provides bearer and connection management. All user IP packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172.
  • the PDN Gateway 172 provides UE IP address allocation as well as other functions.
  • the PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176.
  • the IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.
  • the BM-SC 170 may provide functions for MBMS user service provisioning and delivery.
  • the BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions.
  • PLMN public land mobile network
  • the MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.
  • MMSFN Multicast Broadcast Single Frequency Network
  • the core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195.
  • the AMF 192 may be in communication with a Unified Data Management (UDM) 196.
  • the AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190.
  • the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195.
  • the UPF 195 provides UE IP address allocation as well as other functions.
  • the UPF 195 is connected to the IP Services 197.
  • the IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a Packet Switch (PS) Streaming (PSS) Service, and/or other IP services.
  • IMS IP Multimedia Subsystem
  • PS Packet Switch
  • PSS Packe
  • the base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology.
  • the base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104.
  • Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device.
  • SIP session initiation protocol
  • PDA personal digital assistant
  • the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) .
  • the UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.
  • the diagrams illustrate examples of different resources that may be used for communications between network elements (e.g., base station 102, UE 104) of the wireless communications system and the access network 100 described above in FIG. 1.
  • the resources may be time-based, frequency-based, or both on time and frequency.
  • FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure.
  • FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe.
  • FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure.
  • FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G NR subframe.
  • the 5G NR frame structure may be frequency division duplexed (FDD) in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be time division duplexed (TDD) in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL.
  • FDD frequency division duplexed
  • TDD time division duplexed
  • the 5G NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and F is flexible for use between DL/UL, and subframe 3 being configured with slot format 1 (with all UL) . While subframes 3, 4 are shown with slot formats 1, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols.
  • UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) .
  • DCI DL control information
  • RRC radio resource control
  • SFI received slot format indicator
  • a frame (10 ms) may be divided into 10 equally sized subframes (1 ms) .
  • Each subframe may include one or more time slots.
  • Subframes may also include mini-slots, which may include 7, 4, or 2 symbols.
  • Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols.
  • the symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols.
  • the symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) .
  • the number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies ⁇ 0 to 4 allow for 1, 2, 4, 8, and 16 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology ⁇ , there are 14 symbols/slot and 2 ⁇ slots/subframe.
  • the subcarrier spacing and symbol length/duration are a function of the numerology.
  • the subcarrier spacing may be equal to 2 ⁇ *15 kHz, where ⁇ is the numerology 0 to 4.
  • the symbol length/duration is inversely related to the subcarrier spacing.
  • the slot duration is 0.25 ms
  • the subcarrier spacing is 60 kHz
  • the symbol duration is approximately 16.67 ⁇ s.
  • Each BWP may have a particular numerology.
  • a resource grid may be used to represent the frame structure.
  • Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers.
  • RB resource block
  • PRBs physical RBs
  • the resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.
  • the RS may include demodulation RS (DM-RS) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE.
  • DM-RS demodulation RS
  • CSI-RS channel state information reference signals
  • the RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .
  • BRS beam measurement RS
  • BRRS beam refinement RS
  • PT-RS phase tracking RS
  • FIG. 2B illustrates an example of various DL channels within a subframe of a frame.
  • the physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs) , each CCE including six RE groups (REGs) , each REG including 12 consecutive REs in an OFDM symbol of an RB.
  • CCEs control channel elements
  • REGs RE groups
  • a PDCCH within one BWP may be referred to as a control resource set (CORESET) .
  • CORESET control resource set
  • a UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth.
  • a primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity.
  • a secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing.
  • the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS.
  • the physical broadcast channel (PBCH) which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block (also referred to as SS block (SSB) ) .
  • the MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) .
  • the physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.
  • SIBs system information blocks
  • some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station.
  • the UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) .
  • the PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH.
  • the PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used.
  • the UE may transmit sounding reference signals (SRS) .
  • the SRS may be transmitted in the last symbol of a subframe.
  • the SRS may have a comb structure, and a UE may transmit SRS on one of the combs.
  • the SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.
  • FIG. 2D illustrates an example of various UL channels within a subframe of a frame.
  • the PUCCH may be located as indicated in one configuration.
  • the PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and hybrid automatic repeat request (HARQ) ACK/NACK feedback.
  • UCI uplink control information
  • the PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.
  • BSR buffer status report
  • PHR power headroom report
  • FIG. 3 is a block diagram of example hardware components of a base station 102 in communication with a UE 104 in an access network.
  • IP packets from the EPC 160 may be provided to a controller/processor 375.
  • the controller/processor 375 implements layer 3 and layer 2 functionality.
  • Layer 3 includes a radio resource control (RRC) layer
  • layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.
  • RRC radio resource control
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC medium access control
  • the controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling
  • the transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions.
  • Layer 1 which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing.
  • the TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) .
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase-shift keying
  • M-QAM M-quadrature amplitude modulation
  • the coded and modulated symbols may then be split into parallel streams.
  • Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream.
  • IFFT Inverse Fast Fourier Transform
  • the OFDM stream is spatially precoded to produce multiple spatial streams.
  • Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing.
  • the channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 104.
  • Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318 TX.
  • Each transmitter 318 TX may modulate an RF carrier with a respective spatial stream for transmission.
  • each receiver 354 RX receives a signal through its respective antenna 352.
  • Each receiver 354 RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356.
  • the TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions.
  • the RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 104. If multiple spatial streams are destined for the UE 104, they may be combined by the RX processor 356 into a single OFDM symbol stream.
  • the RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) .
  • FFT Fast Fourier Transform
  • the frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal.
  • the symbols on each subcarrier, and the reference signal are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 102. These soft decisions may be based on channel estimates computed by the channel estimator 358.
  • the soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 102 on the physical channel.
  • the data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.
  • the controller/processor 359 can be associated with a memory 360 that stores program codes and data.
  • the memory 360 may be referred to as a computer-readable medium.
  • the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160.
  • the controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
  • the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.
  • RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting
  • PDCP layer functionality associated with header
  • Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 102 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing.
  • the spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.
  • the UL transmission is processed at the base station 102 in a manner similar to that described in connection with the receiver function at the UE 104.
  • Each receiver 318RX receives a signal through its respective antenna 320.
  • Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.
  • the controller/processor 375 can be associated with a memory 376 that stores program codes and data.
  • the memory 376 may be referred to as a computer-readable medium.
  • the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 104. IP packets from the controller/processor 375 may be provided to the EPC 160.
  • the controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
  • At the UE 104, least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with the fast resend component 198 of FIG. 1.
  • Wireless communication systems may be configured to share available system resources and provide various telecommunication services (e.g., telephony, video, data, messaging, broadcasts, etc. ) based on multiple-access technologies such as CDMA systems, TDMA systems, FDMA systems, OFDMA systems, SC-FDMA systems, TD-SCDMA systems, etc. that support communication with multiple users.
  • multiple-access technologies such as CDMA systems, TDMA systems, FDMA systems, OFDMA systems, SC-FDMA systems, TD-SCDMA systems, etc.
  • common protocols that facilitate communications with wireless devices are adopted in various telecommunication standards.
  • communication methods associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communication (URLLC) may be incorporated in the 5G NR telecommunication standard, while other aspects may be incorporated in the 4G LTE standard.
  • eMBB enhanced mobile broadband
  • mMTC massive machine type communications
  • URLLC ultra-reliable low late
  • FIG. 4 is a call flow diagram 400 illustrating actions and messaging associated with a fast resend of a PDU session request in communications between UE 104 and a base station 102.
  • UE 104 may include one or more protocol layer entities for implementing the fast resend of the PDU session request, such as a 5G session management (5GSM) sublayer 401 that may provide PDU session handling capabilities to the UE 104, and a 5G mobility management (5GMM) sublayer 402 that may provide network connection capabilities to the UE 104.
  • 5GSM 5G session management
  • 5GMM 5G mobility management
  • the UE 104 and/or 5GSM sublayer 401 may generate a PDU session request and may provide, at 405, the PDU session request to the 5GMM sublayer 402.
  • the 5GSM sublayer 401 may provide the PDU session request by sending a first NAS 5GMM DATA REQ message carrying the PDU session request.
  • the PDU session request may be a request to establish a PDU session (e.g., PDU SESSION ESTABLISHMENT REQUEST in 5GS) , a request to modify an existing PDU session (e.g., PDU SESSION MODIFICATION REQUEST in 5GS) , or a request to release an existing PDU session (e.g., PDU SESSION RELEASE REQUEST in 5GS) .
  • the 5GSM sublayer 401 may generate a PDU session request based on receiving instructions from a data service and/or application on the UE 104, wherein the instructions request the establishment of a PDU session, the modification of an existing PDU session, or the release of an existing PDU session.
  • the UE 104 and/or the 5GSM sublayer 401 may additionally start a retransmission timer (e.g., timer T3580 for an establishment request, timer T3581 for a modification request, or timer T3582 for a release request in 5GS) in association with providing the PDU session request to the 5GMM sublayer 402.
  • the retransmission timer may be configured to run for a predetermined time duration (e.g., 16 seconds) and to expire after completion of the predetermined time duration.
  • a NAS protocol may trigger retransmission of the PDU session request after expiration of the retransmission timer.
  • a timer duration of 16 seconds may be too long for requests associated with an IMS core, a URLLC service, or an eMBB service.
  • the UE 104 and/or the 5GMM sublayer 402 may determine that a current state of the 5GMM sublayer 402 may be a wrong state for transmitting the PDU session request to the base station 102.
  • the wrong state of the 5GMM sublayer 402 may comprise a deregistered state (e.g., 5GMM-DEREGISTERED in 5GS) , a network search state, a PLMN search state, a no cell available state, an RRC layer idle or out-of-service state, or the like.
  • the wrong state of the UE 104 may be a state in which the UE 104 is not currently capable of transmitting the PDU session request to the base station 102.
  • a UE 104 comprising a Dual-Subscriber Identity Module (SIM) Dual Standby (DSDS) capability may have an increased likelihood of encountering the aforementioned wrong state scenario as such a UE may share transmission resources between multiple subscriptions and thereby may be more likely to be in a state in which the UE is unable transmit the PDU session request.
  • SIM Dual-Subscriber Identity Module
  • DSDS Dual Standby
  • the 5GMM sublayer 402 may reject, at 415, the PDU session request.
  • the 5GMM sublayer 402 may send to the 5GSM sublayer 401 a NAS 5GMM DATA REJ RSP message indicating that the PDU session request has been rejected.
  • the NAS 5GMM DATA REJ RSP message may further carry an indication of the wrong state.
  • the UE 104 and/or the 5GMM sublayer 402 may change to a new correct state faster (e.g., 1 second) than the retransmission timer duration (e.g., 16 seconds) .
  • a PDU session request that is retransmitted based on expiration of the retransmission timer, rather than based on a state change of the 5GMM sublayer 402 may cause a decreased user experience as the extra waiting time increases latency and causes delays.
  • the UE 104 may be configured to transmit a message corresponding to the PDU session request based on a state change of the 5GMM sublayer 402 to a correct state.
  • the UE 104 and/or the 5GSM 401 and 5GMM 402 may operate to generate and transmit the PDU session request immediately after identifying a state change of the 5GMM sublayer 402, e.g., into the correct state, and while the retransmission timer may still be running) .
  • the state of the 5GMM sublayer 402 may change, at 420, to a new state that is a correct state for transmitting a PDU session request.
  • the correct state of the 5GMM sublayer 402 may comprise a registered state (e.g., 5GMM-REGISTERED in 5GS) , a network search complete state, a PLMN search complete state, an RRC layer connected state, or the like.
  • the 5GMM sublayer 402 may identify the new state to the 5GSM sublayer 401 by sending a STATE CHANGE IND message.
  • the STATE CHANGE IND message may comprise an identification of the correct state.
  • the 5GSM sublayer 401 may, at 430, send a second NAS 5GMM DATA REQ message carrying the PDU session request to the 5GMM sublayer 402 prior to expiration of the retransmission timer started in association with sending the PDU session request at 405.
  • the 5GSM sublayer 401 may additionally restart the retransmission timer in association with providing the PDU session request to the 5GMM sublayer 402 for a second time.
  • the 5GSM sublayer 401 may maintain a current value of a counter in response to providing the PDU session request for a second time due to a wrong state of the 5GMM sublayer 402.
  • the counter may indicate a number of times that the retransmission timer has expired.
  • the value of the timer is not increased based on sending the second PDU session request prior to expiration of the timer, as the timer did not reach its expiration.
  • this fast resend of the PDU session requests avoids increasing the counter, and thus prolongs subsequent, more drastic procedures (e.g., further delaying the PDU session request) that may occur when the counter reaches a counter threshold.
  • the 5GMM sublayer 402 may transmit the PDU session request to the base station 102. If or when the base station 102 receives the transmitted PDU session request, the base station may transmit, at 430, a response to the PDU session request.
  • the response to the PDU session request may be a PDU acceptance message indicating acceptance of the PDU session request (e.g., PDU SESSION ESTABLISHMENT ACCEPT, PDU SESSION MODIFICATION COMMAND, or PDU SESSION RELEASE COMMAND in 5GS) .
  • the 5GMM sublayer 402 may indicate to the 5GSM sublayer 401 that the PDU session request has been accepted.
  • the 5GMM sublayer 402 may send to the 5GSM sublayer 401 a NAS 5GMM DATA ACCEPT RSP message.
  • the NAS 5GMM DATA ACCEPT RSP message may comprise the PDU acceptance message from the base station 102.
  • the NAS 5GMM DATA ACCEPT RSP message may carry the acceptance response message from the base station 102.
  • the 5GSM sublayer 401 may additionally stop the retransmission timer in association with receiving acceptance of the PDU session request.
  • a PDU session may be established based on receiving a PDU acceptance message to a PDU session request (e.g., PDU SESSION ESTABLISHMENT ACCEPT in 5GS) .
  • a PDU session request e.g., PDU SESSION ESTABLISHMENT ACCEPT in 5GS
  • an existing PDU session may be modified based on receiving a PDU acceptance message to a PDU session modification request (e.g., PDU SESSION MODIFICATION COMMAND in 5GS) .
  • an existing PDU session may be released based on receiving a PDU acceptance message to a PDU session release request (e.g., PDU SESSION RELEASE COMMAND in 5GS) .
  • the call flow diagram 400 may end, at 450, subsequent thereto.
  • UE 104 may perform a method 600 of wireless communication, by such as via execution of fast resend component 198 by processor 505 and/or memory 510.
  • Processor 505 may include or may be similar in many respects to at least one of the TX processor 368, the RX processor 356, and the controller/processor 359 described above with reference to FIG. 3 and may include additional features not mentioned above.
  • memory 510 may include or may be similar in many respects to memory 360 described above with reference to FIG. 3 and may include additional features not mentioned above.
  • the method 600 includes generating a PDU session request.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or generating component 520 may be configured to or may comprise means for generating the PDU session request.
  • the generating at block 602 may include generating a PDU session request and providing the PDU session request to a 5GMM protocol layer.
  • the PDU session request may be a request to establish a PDU session (e.g., PDU SESSION ESTABLISHMENT REQUEST in 5GS) , a request to modify an existing PDU session (e.g., PDU SESSION MODIFICATION REQUEST in 5GS) , or a request to release an existing PDU session (e.g., PDU SESSION RELEASE REQUEST in 5GS) .
  • the generating at block 602 may further include sending a first NAS 5GMM DATA REQ message carrying the PDU session request.
  • the generating at block 602 may be performed in response to a request from a data service entity (e.g., an IMS, a PS Streaming Service, and/or other IP services) or from an application executing in the UE to initiate a PDU session procedure.
  • the PDU session procedures may establish a PDU session, transfer an existing PDU session from one network access type to another (e.g., from non-3GPP access to 3GPP access) , modify an existing PDU session (e.g., request specific quality-of-service (QoS) handling, segregate service data flows, or indicate certain relevant parameters and capabilities like packet filter support, maximum data rate and the like) , or terminate or release an existing PDU session.
  • QoS quality-of-service
  • the method 600 includes determining that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or determining component 525 may be configured to or may comprise means for determining that the PDU session request is not to be transmitted by the UE based at least on a determination that the UE is in a wrong state.
  • the determining at block 604 may include determining that a current state of the 5GMM protocol layer is in a wrong state for transmitting the PDU session request to the base station 102. That is, the current state of the 5GMM protocol layer may not support transmitting the PDU session request to the base station 102.
  • the wrong state of the 5GMM protocol layer may comprise a deregistered state (e.g., 5GMM-DEREGISTERED in 5GS) , a network search state, a PLMN search state, a no cell available state, an RRC layer idle or out-of-service state, or the like.
  • the determining at block 604 may further include rejecting the PDU session request based at least in part on the determination that the 5GMM protocol layer is in a wrong state.
  • a NAS 5GMM DATA REJ RSP message may be sent in response to the first NAS 5GMM DATA REQ message.
  • the NAS 5GMM DATA REJ RSP message may indicate that the PDU session request has been rejected.
  • the NAS 5GMM DATA REJ RSP message may further carry an indication of the wrong state.
  • the determining at block 604 may be performed to identify that the PDU session request failed based at least on the current state of the 5GMM protocol layer not supporting transmission of the PDU session request to the base station 102 (i.e., the wrong state) .
  • the method 600 includes identifying a state change indicating that the UE is in a correct state.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or identifying component 530 may be configured to or may comprise means for identifying a state change indicating that the UE is in a correct state.
  • the identifying at block 606 may include detecting a state change of the 5GMM protocol layer to a new state and determining that the new state of the 5GMM protocol layer is a correct state that supports transmitting the PDU session request to the base station 102.
  • the correct state of the 5GMM protocol layer may comprise a registered state (e.g., 5GMM-REGISTERED in 5GS) , a network search complete state, a PLMN search complete state, an RRC layer connected state, or the like.
  • the identifying at block 606 may further include sending a STATE CHANGE IND message indicating a state change of the 5GMM protocol layer.
  • the STATE CHANGE IND message may further comprise an identification of the correct state.
  • the identifying at block 606 may be performed to trigger a transmission of the PDU session request based on a state change of the 5GMM protocol layer.
  • the PDU session request may be transmitted immediately after a state change of the 5GMM protocol layer and while a retransmission timer associated with the PDU session request may still be running.
  • the method 600 includes transmitting the PDU session request in response to identifying the state change.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or transmitting component 535 may be configured to or may comprise means for transmitting the PDU session request in response to identifying the state change.
  • the transmitting at block 608 may include transmitting the PDU session request to the base station 102 in response to identifying the state change.
  • the state change indicating that the 5GMM protocol layer is in a correct state for transmitting the PDU session request to the base station 102.
  • the transmitting at block 608 may be performed to initiate a PDU session procedure to establish, modify, or release a PDU session.
  • the method 600 may further include starting, in response to generating the PDU session request, a PDU session request retransmission timer configured to run a time duration before an expiration.
  • a PDU session request retransmission timer configured to run a time duration before an expiration.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or starting component 540 may be configured to or may comprise means for starting, in response to generating the PDU session request, a PDU session request retransmission timer configured to run a time duration before an expiration.
  • the starting at block 702 may include starting a PDU session request retransmission timer in response to generating the PDU session request.
  • the PDU session request retransmission timer may be configured to run for a predetermined time duration (e.g., 16 seconds) and to expire after completion of the predetermined time duration. If or when the PDU session request is a request to establish a PDU session (e.g., PDU SESSION ESTABLISHMENT REQUEST in 5GS) , the PDU session request retransmission timer may correspond to a T3580 timer in 5GS.
  • the PDU session request retransmission timer may correspond to a T3581 timer in 5GS. If or when the PDU session request is a request to release a PDU session (e.g., PDU SESSION RELEASE REQUEST in 5GS) , the PDU session request retransmission timer may correspond to a T3582 timer in 5GS.
  • the starting at block 602 may be performed to trigger transmission of the PDU session request after expiration of the PDU session request retransmission timer.
  • the transmitting at block 608 of the PDU session request comprises transmitting the PDU session request prior to the expiration of the PDU session request retransmission timer.
  • the transmitting at block 704 may include transmitting the PDU session request to the base station 102 while the PDU session request retransmission timer is still running. Further, for example, the transmitting at block 704 may be performed based on the identifying the state change instead of the expiration of the PDU session request retransmission timer.
  • the state change may occur faster (e.g., 1 second) than the PDU session request retransmission timer duration (e.g., 16 seconds) .
  • the PDU session request retransmission timer duration of 16 seconds may be too long for PDU session requests associated with an IMS core, a URLLC service, or an eMBB service.
  • retransmission of PDU session requests based on expiration of the PDU session request retransmission timer instead of based on a state change of the 5GMM protocol layer, may result in a decreased user experience.
  • the method 600 may further include restarting the PDU session request retransmission timer in response to transmitting the PDU session request.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or restarting component 545 may be configured to or may comprise means for restarting the PDU session request retransmission timer in response to transmitting the PDU session request.
  • the restarting at block 802 may include restarting the PDU session request retransmission timer in response to transmitting the PDU session request based on a state change of the 5GMM protocol layer.
  • the restarting at block 802 may further include restarting the PDU session request retransmission timer prior to the expiration of the PDU session request retransmission timer.
  • the restarting at block 802 may further include restarting the PDU session request retransmission timer if or when the PDU session request retransmission timer expires prior to identifying the state change of the 5GMM protocol layer and prior to receiving a response to the PDU session request from the base station 102.
  • the PDU session request retransmission timer may be restarted based on a counter not exceeding a threshold of PDU session request retransmission timer expirations.
  • the threshold may be preconfigured to a maximum number of five (5) PDU session request retransmission timer expirations.
  • the restarting at block 802 may be performed to restart the predetermined time period allocated for the base station 102 to respond to the PDU session request.
  • the method 600 may further include maintaining a current value of a counter in response to transmitting the PDU session request based on the state change and prior to an expiration of a PDU session request retransmission timer associated with generating the PDU session request, the counter indicating a number of times that the PDU session request retransmission timer has expired.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or maintaining component 550 may be configured to or may comprise means for maintaining a current value of a counter, in response to transmitting the PDU session request based on the state change and prior to an expiration of a PDU session request retransmission timer associated with generating the PDU session request, the counter indicating a number of times that the PDU session request retransmission timer has expired.
  • the maintaining at block 902 may include abstaining from incrementing the counter when restarting the PDU session request retransmission timer in response to transmitting the PDU session request based on a state change of the 5GMM protocol layer. That is, instead of increasing the counter value, which is may be what normally happens when sending the second PDU session request based on expiration of the PDU session request retransmission timer, the value of the counter in this case may remain unchanged by the PDU session request retransmission timer restarting operation even though a second PDU session request has been sent. This avoids the counter from incrementing closer to or reaching a counter threshold, which may then trigger other operations that would further delay transmission of subsequent PDU session requests.
  • the maintaining at block 902 may be performed to indicate that the PDU session request retransmission timer was restarted based on a state change of the 5GMM protocol layer and not based on an expiration of the PDU session request retransmission timer.
  • the method 600 may further includes receiving, from a network device, a response to the PDU session request, the response indicating an acceptance of the PDU session request.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or receiving component 555 may be configured to or may comprise means for receiving, from a network device, a response to the PDU session request, the response indicating an acceptance of the PDU session request.
  • the receiving at block 1002 may include receiving, from the base station 102, a PDU acceptance message if or when the base station 102 received the transmitted PDU session request.
  • the PDU acceptance message may be a PDU SESSION ESTABLISHMENT ACCEPT in 5GS.
  • the PDU acceptance message may be a PDU SESSION MODIFICATION COMMAND in 5GS.
  • the PDU acceptance message may be a PDU SESSION MODIFICATION COMMAND in 5GS.
  • the receiving at block 1002 may further include stopping the PDU session request retransmission timer.
  • the receiving at block 1002 may be performed to determine that the transmitted PDU session request was accepted and to stop the PDU session request retransmission timer.
  • the method 600 may further include establishing, modifying, or releasing the PDU session based on the acceptance.
  • UE 104, processor 505, memory 510, fast resend component 198, and/or establishing component 560 may be configured to or may comprise means for establishing, modifying, or releasing the PDU session based on the acceptance.
  • the establishing at block 1004 may include establishing a PDU session based on receiving a PDU session establishment acceptance message (e.g., PDU SESSION ESTABLISHMENT ACCEPT in 5GS) .
  • the establishing at block 1004 may further include modifying an existing PDU session based on receiving a PDU session modification command (e.g., PDU SESSION MODIFICATION COMMAND in 5GS) .
  • the establishing at block 1004 may further include releasing an existing PDU session based on receiving a PDU session release command (e.g., PDU SESSION RELEASE COMMAND in 5GS) .
  • the establishing at block 1004 may be performed to continue a particular PDU session procedure initiated by the transmission of the PDU session request.
  • a UE 104 may be triggered to perform a PLMN search based at least on a decrease of cell power. As such, the UE 104 may enter a wrong state in which the UE 104 is unable to transmit a PDU session request. While the UE 104 is performing the PLMN search, the UE 104 may generate a PDU session request, for example, based on a request from a data service or an application. Based at least on a determination that the UE 104 is in the wrong state, the UE 104 may omit transmitting the PDU session request and may initiate a retransmission timer with a fixed predetermined duration.
  • the retransmission timer may be a T3580 timer with a 16 second duration.
  • the UE 104 may send the PDU session request (e.g., a PDU session establishment request) before the retransmission timer expires, based at least on an indication that the UE 104 has transitioned into a correct state.
  • Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C.
  • combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C.

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

Abstract

Des modes de réalisation illustratifs comprennent un procédé, un appareil et un support lisible par ordinateur destinés à une communication sans fil à effectuer par un équipement utilisateur (UE), comprenant la génération d'une demande de session d'unité de données de protocole (PDU). Les modes de réalisation consistent en outre à déterminer que la demande de session PDU n'est pas à transmettre par l'UE sur la base au moins d'une détermination que l'UE est dans un mauvais état. De plus, les modes de réalisation consistent en outre à identifier un changement d'état indiquant que l'UE est dans un état correct. De plus, les modes de réalisation consistent en outre à transmettre la demande de session PDU en réponse à l'identification du changement d'état.
PCT/CN2020/117453 2020-09-24 2020-09-24 Retransmission rapide d'une demande de session d'unité de données de protocole WO2022061652A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018169341A1 (fr) * 2017-03-16 2018-09-20 Samsung Electronics Co., Ltd. Procédé de mise à jour de connexion de session pdu initiée par un réseau entre un terminal et un réseau
CN109661039A (zh) * 2019-01-15 2019-04-19 北京泰德东腾通信技术有限公司 5g会话建立方法及会话释放的协议一致性测试方法
US20190349742A1 (en) * 2018-05-11 2019-11-14 Lg Electronics Inc. Method and apparatus for utilizing ladn in wireless communication system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018169341A1 (fr) * 2017-03-16 2018-09-20 Samsung Electronics Co., Ltd. Procédé de mise à jour de connexion de session pdu initiée par un réseau entre un terminal et un réseau
US20190349742A1 (en) * 2018-05-11 2019-11-14 Lg Electronics Inc. Method and apparatus for utilizing ladn in wireless communication system
CN109661039A (zh) * 2019-01-15 2019-04-19 北京泰德东腾通信技术有限公司 5g会话建立方法及会话释放的协议一致性测试方法

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