WO2021223091A1 - Sélection de ressources de procédure d'accès aléatoire - Google Patents

Sélection de ressources de procédure d'accès aléatoire Download PDF

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Publication number
WO2021223091A1
WO2021223091A1 PCT/CN2020/088711 CN2020088711W WO2021223091A1 WO 2021223091 A1 WO2021223091 A1 WO 2021223091A1 CN 2020088711 W CN2020088711 W CN 2020088711W WO 2021223091 A1 WO2021223091 A1 WO 2021223091A1
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WO
WIPO (PCT)
Prior art keywords
random access
access procedure
synchronization signal
resource
contention
Prior art date
Application number
PCT/CN2020/088711
Other languages
English (en)
Inventor
Jinglin Zhang
Haojun WANG
Yi Liu
Zhenqing CUI
Jingming CHANG
Hong Wei
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Qualcomm Incorporated
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Publication date
Application filed by Qualcomm Incorporated filed Critical Qualcomm Incorporated
Priority to PCT/CN2020/088711 priority Critical patent/WO2021223091A1/fr
Publication of WO2021223091A1 publication Critical patent/WO2021223091A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0695—Hybrid systems, i.e. switching and simultaneous transmission using beam selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H04W74/006—Transmission of channel access control information in the downlink, i.e. towards the terminal

Definitions

  • the following relates generally to wireless communications and more specifically to random access procedure resource selection.
  • Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) .
  • Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems.
  • 4G systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems
  • 5G systems which may be referred to as New Radio (NR) systems.
  • a wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .
  • UE user equipment
  • a UE may perform random access procedures to communicate with a base station in a wireless communications system.
  • the UE may perform contention based random access (CBRA) or contention-free random access (CFRA) procedures.
  • CBRA contention based random access
  • CFRA contention-free random access
  • the described techniques relate to improved methods, systems, devices, and apparatuses that support random access procedure resource selection.
  • the described techniques provide for a user equipment (UE) performing a random access procedure in communication with a base station in a wireless communications system.
  • the UE may receive control signaling indicating a first synchronization signal index associated with performing a contention-free random access procedure.
  • the UE may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the UE may then perform the random access procedure using the selected resource.
  • a method of wireless communications at a UE may include receiving control signaling indicating a first synchronization signal index associated with performing a contention-free random access procedure, selecting a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and performing a random access procedure using the selected resource.
  • the apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory.
  • the instructions may be executable by the processor to cause the apparatus to receive control signaling indicating a first synchronization signal index associated with performing a contention-free random access procedure, select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and perform a random access procedure using the selected resource.
  • the apparatus may include means for receiving control signaling indicating a first synchronization signal index associated with performing a contention-free random access procedure, selecting a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and performing a random access procedure using the selected resource.
  • a non-transitory computer-readable medium storing code for wireless communications at a UE is described.
  • the code may include instructions executable by a processor to receive control signaling indicating a first synchronization signal index associated with performing a contention-free random access procedure, select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and perform a random access procedure using the selected resource.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving configuration signaling indicating a set of contention-free random access (CFRA) resources associated with a beam failure recovery (BFR) random access procedure.
  • CFRA contention-free random access
  • BFR beam failure recovery
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining one or more available resources from the set of CFRA resources associated with the BFR random access procedure based on a power measurement associated with the set of resources.
  • the random access procedure includes a contention free random access procedure
  • the selected resource includes a resource from the one or more available CFRA resources.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining all resources from the set of CFRA resources associated with the BFR random access procedure may be unavailable based on a power measurement associated with the set of resources.
  • the random access procedure includes a contention based random access (CBRA) procedure
  • the selected resource includes a resource selected based on the CBRA procedure.
  • CBRA contention based random access
  • the configuration signaling includes radio resource control signaling.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that CFRA resources associated with a BFR random access procedure may be not configured.
  • the random access procedure includes a CBRA procedure
  • the selected resource includes a resource selected based on the CBRA procedure
  • control signaling includes a physical downlink control channel order command.
  • the first synchronization signal index includes a synchronization signal block (SSB) index.
  • SSB synchronization signal block
  • the selected resource other than the indicated first synchronization signal index for transmitting the first message of a random access procedure includes a random access occasion for transmitting a random access preamble message.
  • a method of wireless communications at a base station may include transmitting control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receiving a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory.
  • the instructions may be executable by the processor to cause the apparatus to transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the apparatus may include means for transmitting control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receiving a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • a non-transitory computer-readable medium storing code for wireless communications at a base station is described.
  • the code may include instructions executable by a processor to transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting configuration signaling indicating a set of resources associated with a BFR random access procedure.
  • the random access procedure includes a contention free random access procedure
  • the selected resource includes a resource from the set of CFRA resources.
  • the configuration signaling includes radio resource control signaling.
  • the random access procedure includes a CBRA procedure
  • the selected resource includes a resource selected based on the CBRA procedure
  • control signaling includes a physical downlink control channel order command.
  • the first synchronization signal index includes a SSB index.
  • the selected resource other than the indicated first synchronization signal index for transmitting the first message of a random access procedure includes a random access occasion for transmitting a random access preamble message.
  • FIG. 1 illustrates an example of a wireless communications system that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 2 illustrates an example of a wireless communications system that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 3 illustrates an example of a decision tree that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 4 illustrates an example of a process flow that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIGs. 5 and 6 show block diagrams of devices that support random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 7 shows a block diagram of a communications manager that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 8 shows a diagram of a system including a device that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIGs. 9 and 10 show block diagrams of devices that support random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 11 shows a block diagram of a communications manager that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIG. 12 shows a diagram of a system including a device that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • FIGs. 13 through 16 show flowcharts illustrating methods that support random access procedure resource selection in accordance with aspects of the present disclosure.
  • a user equipment may communicate with a base station in a wireless communications system.
  • the UE may perform random access procedures to obtain access to a serving base station.
  • the random access procedure may include an initial first random access message transmitted by the UE to the base station.
  • the first initial random access message may include a physical random access channel (PRACH) preamble.
  • PRACH physical random access channel
  • Random access procedures may include both contention based random access (CBRA) and contention-free random access (CFRA) .
  • CBRA may include cases where multiple UEs randomly select PRACH preambles and transmit the PRACH preamble message.
  • CFRA may include cases where the network, via a base station, assigns a PRACH preamble to a UE. Further, in CFRA procedures, a base station may transmit a physical downlink control channel (PDCCH) order command to a UE. This order command may indicate a synchronization signal block (SSB) index, and the UE may then use the indicated SSB index for a CFRA procedure.
  • PDCCH physical downlink control channel
  • the UE may not be able to detect the indicated SSB index.
  • the CFRA procedure may cause inefficiencies.
  • the base station may transmit a second downlink message of the random access procedure using the indicated SSB, which the UE is unable to detect. These detection errors may lead to increased retransmissions and latency.
  • the UE may determine to use an alternative random access resource or an alternative random access procedure. If the UE is unable to detect the SSB indicated in the control signaling from the base station, the UE may determine to perform CBRA, or the UE may perform CFRA using resources that were previously configured for beam failure recovery (BFR) random access procedures, in cases where the BFR random access resources are available.
  • BFR beam failure recovery
  • aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are then described in the context of a decision tree and a process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to random access procedure resource selection.
  • FIG. 1 illustrates an example of a wireless communications system 100 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130.
  • the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network.
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • LTE-A Pro LTE-A Pro
  • NR New Radio
  • the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.
  • ultra-reliable e.g., mission critical
  • the base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities.
  • the base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125.
  • Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125.
  • the coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.
  • the UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times.
  • the UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1.
  • the UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment) , as shown in FIG. 1.
  • network equipment e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment
  • the base stations 105 may communicate with the core network 130, or with one another, or both.
  • the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) .
  • the base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both.
  • the backhaul links 120 may be or include one or more wireless links.
  • One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.
  • a base transceiver station a radio base station
  • an access point a radio transceiver
  • a NodeB an eNodeB (eNB)
  • eNB eNodeB
  • a next-generation NodeB or a giga-NodeB either of which may be referred to as a gNB
  • gNB giga-NodeB
  • a UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples.
  • a UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer.
  • PDA personal digital assistant
  • a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.
  • WLL wireless local loop
  • IoT Internet of Things
  • IoE Internet of Everything
  • MTC machine type communications
  • the UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.
  • devices such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.
  • the UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers.
  • the term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125.
  • a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) .
  • BWP bandwidth part
  • Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling.
  • the wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation.
  • a UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration.
  • Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.
  • FDD frequency division duplexing
  • TDD time division duplexing
  • a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.
  • a carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) and may be positioned according to a channel raster for discovery by the UEs 115.
  • E-UTRA evolved universal mobile telecommunication system terrestrial radio access
  • a carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology) .
  • the communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115.
  • Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode) .
  • a carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100.
  • the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz) ) .
  • Devices of the wireless communications system 100 e.g., the base stations 105, the UEs 115, or both
  • the wireless communications system 100 may include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths.
  • each served UE 115 may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth.
  • Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .
  • MCM multi-carrier modulation
  • OFDM orthogonal frequency division multiplexing
  • DFT-S-OFDM discrete Fourier transform spread OFDM
  • a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related.
  • the number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) .
  • a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.
  • One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing ( ⁇ f) and a cyclic prefix.
  • a carrier may be divided into one or more BWPs having the same or different numerologies.
  • a UE 115 may be configured with multiple BWPs.
  • a single BWP for a carrier may be active at a given time and communications for the UE 115 may be restricted to one or more active BWPs.
  • Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) .
  • Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .
  • SFN system frame number
  • Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration.
  • a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots.
  • each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing.
  • Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) .
  • a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.
  • a subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) .
  • TTI duration e.g., the number of symbol periods in a TTI
  • the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .
  • Physical channels may be multiplexed on a carrier according to various techniques.
  • a physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques.
  • a control region e.g., a control resource set (CORESET)
  • CORESET control resource set
  • a control region for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier.
  • One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115.
  • one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner.
  • An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size.
  • Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.
  • Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof.
  • the term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) .
  • a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates.
  • Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105.
  • a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.
  • a macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell.
  • a small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells.
  • Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) .
  • a base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.
  • a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.
  • protocol types e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB)
  • NB-IoT narrowband IoT
  • eMBB enhanced mobile broadband
  • a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110.
  • different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105.
  • the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105.
  • the wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.
  • the wireless communications system 100 may support synchronous or asynchronous operation.
  • the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time.
  • the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time.
  • the techniques described herein may be used for either synchronous or asynchronous operations.
  • Some UEs 115 may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) .
  • M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention.
  • M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program.
  • Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.
  • Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) .
  • half-duplex communications may be performed at a reduced peak rate.
  • Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications) , or a combination of these techniques.
  • some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.
  • a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.
  • the wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof.
  • the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications.
  • the UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) .
  • Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) .
  • MCPTT mission critical push-to-talk
  • MCVideo mission critical video
  • MCData mission critical data
  • Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications.
  • the terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.
  • a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) .
  • D2D device-to-device
  • P2P peer-to-peer
  • One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105.
  • Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105.
  • groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group.
  • a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.
  • the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115) .
  • vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these.
  • V2X vehicle-to-everything
  • V2V vehicle-to-vehicle
  • a vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system.
  • vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or with both.
  • V2N vehicle-to-network
  • the core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions.
  • the core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) .
  • EPC evolved packet core
  • 5GC 5G core
  • MME mobility management entity
  • AMF access and mobility management function
  • S-GW serving gateway
  • PDN Packet Data Network gateway
  • UPF user plane function
  • the control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130.
  • NAS non-access stratum
  • User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions.
  • the user plane entity may be connected to the network operators IP services 150.
  • the operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.
  • Some of the network devices may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) .
  • Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) .
  • Each access network transmission entity 145 may include one or more antenna panels.
  • various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .
  • the wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) .
  • the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length.
  • UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors.
  • the transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.
  • HF high frequency
  • VHF very high frequency
  • the wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band.
  • SHF super high frequency
  • EHF extremely high frequency
  • the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device.
  • mmW millimeter wave
  • the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions.
  • the techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.
  • the wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands.
  • the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band.
  • LAA License Assisted Access
  • LTE-U LTE-Unlicensed
  • NR NR technology
  • an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band.
  • devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance.
  • operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) .
  • Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.
  • a base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming.
  • the antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming.
  • one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower.
  • antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations.
  • a base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115.
  • a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.
  • an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.
  • the base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing.
  • the multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas.
  • Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) .
  • Different spatial layers may be associated with different antenna ports used for channel measurement and reporting.
  • MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.
  • SU-MIMO single-user MIMO
  • Beamforming which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device.
  • Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference.
  • the adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device.
  • the adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .
  • a base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations.
  • a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115.
  • Some signals e.g., synchronization signals, reference signals, beam selection signals, or other control signals
  • the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission.
  • Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.
  • a transmitting device such as a base station 105
  • a receiving device such as a UE 115
  • Some signals may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) .
  • the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions.
  • a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.
  • transmissions by a device may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115) .
  • the UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands.
  • the base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS) , a channel state information reference signal (CSI-RS) ) , which may be precoded or unprecoded.
  • a reference signal e.g., a cell-specific reference signal (CRS) , a channel state information reference signal (CSI-RS)
  • CRS cell-specific reference signal
  • CSI-RS channel state information reference signal
  • the UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook) .
  • PMI precoding matrix indicator
  • codebook-based feedback e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook
  • a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .
  • a receiving device may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals.
  • receive configurations e.g., directional listening
  • a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions.
  • receive beamforming weight sets e.g., different directional listening weight sets
  • a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal) .
  • the single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR) , or otherwise acceptable signal quality based on listening according to multiple beam directions) .
  • SNR signal-to-noise ratio
  • the wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack.
  • communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based.
  • a Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels.
  • RLC Radio Link Control
  • a Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels.
  • the MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency.
  • the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data.
  • RRC Radio Resource Control
  • transport channels may be mapped to physical channels.
  • the UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully.
  • Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125.
  • HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) .
  • FEC forward error correction
  • ARQ automatic repeat request
  • HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) .
  • a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.
  • a UE 115 may perform a random access procedure in communication with a base station 105 in a wireless communications system.
  • the UE 115 may receive control signaling, from a base station 105 indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the UE 115 may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the UE 115 may randomly select a resource for transmitting a first message of a random access procedure based on a CBRA procedure.
  • the UE may select a resource associated with contention free random access BFR resources, if such resources were previously configured for the UE 115 and are available at the time of selection.
  • the UE 115 may then perform the random access procedure using the selected resource. For example, the UE 115 may transmit a first random access message to a base station 105.
  • FIG. 2 illustrates an example of a wireless communications system 200 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • wireless communications system 200 may implement aspects of wireless communication system 100.
  • Base station 105-a may serve one or more UEs 115, including UE 115-a, in a coverage area 110-a.
  • UE 115-a and base station 105-a may communicate over a communication channel 205.
  • the UE 115-a and base station 105-a may initiate communication based on a random access procedure 215.
  • the random access procedure 215 may be a CFRA or a CBRA, depending on a communication configuration.
  • the random access procedure 215 may be an example of a two-step random access procedure or a four-step random access procedure.
  • a two-step random access procedure may include two messages between UE 15-a and base station 105-a, after which the UE 115-a may have the RRC connection established with the base station 105-a.
  • the first random access message (e.g., referred to as Message A) , may correspond to the first and third messages of a four-step random access procedure, and the second random access message (e.g., referred to as Message B) , may correspond to the second and fourth message of a four-step random access procedure.
  • the UE 115-a may send a first random access message to the base station 105-a.
  • the first random access message may include a random access preamble and uplink data, which indicates to the base station 105-a that the UE 115-a is requesting to establish the RRC connection.
  • base station 105-a may indicate preamble for UE 115-a to use for the first random access message.
  • UE 115-a may select a preamble from a group of preambles.
  • the base station 105-a may receive the first random access message and transmit a second random access message, including a random access response and an RRC contention resolution, to the UE 115-a.
  • the second random access message may indicate contention resolution and completion of the random access procedure if the first random access message is successful.
  • Base station 105-a may transmit control signaling 210 to UE 115-a.
  • the control signaling 210 may include an indication of a first synchronization signal index for performing a CFRA.
  • the synchronization signal index may be a SSB index (e.g., SSB i ) .
  • the control signaling 210 may be a PDCCH order command or some other signaling that indicates the synchronization signal index.
  • the control signaling 210 may be transmitted by base station 105-a to trigger the CFRA process at UE 115-a.
  • the PDCCH order command may be of a particular downlink control information (DCI) format (e.g., DCI 1_0) .
  • the cyclic redundancy check (CRC) of the DCI may be scrambled by a cell radio network temporary identifier (C-RNTI) , which may indicate that the DCI is for a random access procedure initiated by the control signaling 210.
  • DCI downlink control information
  • the control signaling 210 may include a specific preamble for UE 115-a to use for the random access procedure. This may indicate a CFRA procedure.
  • UE 115-a may be configured to use the first synchronization signal index (e.g., the SSB i ) that is indicated in the control signaling 210.
  • the first synchronization signal index e.g., the SSB i
  • UE 115-a may not be able to detect the first synchronization signal index.
  • the UE 115-a may have moved or there may be a blockage that prevents the successful reception and/or decoding of the synchronization signal.
  • UE 115-a may not be able to receive subsequent random access messages from base station 105-a, as the subsequent random access message (e.g., a second random access message, random access Msg2) may be transmitted by base station 105-a using the first synchronization signal index.
  • the subsequent random access message e.g., a second random access message, random access Msg2
  • UE 115-a may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure 215.
  • a resource that UE 115-a may select include but are not limited to a random access preamble, time resources, frequency resources, directional beams, or code resources.
  • UE 115-a may either trigger a CFRA procedure using a different resource, or may trigger a CBRA procedure instead.
  • UE 115-a may determine to trigger a CFRA procedure using a different resource, based on UE 115-a previously receiving a CFRA BFR resource.
  • base station 105-a may transmit RRC signaling indicating a set of CFRA resources associated with a BFR random access procedure.
  • This set of CFRA resources may include synchronization signal index resources (e.g., a set of SSB resources) for a BFR random access request procedure by UE 115-a.
  • UE 115-a my perform reference signal receive power (RSRP) measurements on the set of BFR random access resources.
  • the set of SSBs corresponding o the random access resource may be indicated in a candidate beam list (e.g., candidateBeamRSList) .
  • UE 115-a may identify a random access resource, such as an SSB, with a RSRP above a RSRP threshold (e.g., rsrp-ThresholdCSI-RS) . Or, UE 115-a may identify a random access resource, such as a CSI-RS, with a CSI-RSRP above the RSRP threshold amongst CSI-RSs in the candidate beam list. In either case, UE 115-a may select either the SSB or the CSI-RS satisfying the threshold, and may use the selected synchronization signal resource for the CFRA random access procedure 215. The selected resource for the random access procedure 215 may thus be different from the first synchronization signal resource indicated in control signaling 210.
  • a RSRP threshold e.g., rsrp-ThresholdCSI-RS
  • UE 115-a may set the preamble index (e.g., PREAMBLE_INDEX) to a random access preamble index corresponding to the selected SSB in the candidate beam list, which is quasi-located with the selected CSI-RS.
  • UE 115-a may set the preamble index to a random access preamble index corresponding to the selected SSB or CSI-RS from the set of random access preambles for BFR requests.
  • This CFRA BFR resource selection may also be based on a corresponding BFR timer (e.g., beamFailureRecoveryTimer) . If the BFR timer is either running or not configured, and the CFRA resources for the BFR request is associated with a synchronization signal index (e.g., a SSB index) , UE 115-a may use the BFR resource indicated in the RRC signaling.
  • a synchronization signal index e.g., a SSB index
  • UE 115-a may determine to trigger a CBRA procedure using a different resource than the first synchronization signal resource, based on UE 115-a not detecting the first synchronization signal resource indicated in control signaling 210, and UE 115-a not receiving RRC signaling for a BFR resource. In these cases, UE 115-a may initiate a CBRA procedure, rather than a CFRA procedure. UE 115-a may measure RSRP of random access resources (e.g., SSBs) indicated in a candidate beam list.
  • RSRP random access resources
  • UE 115-a may use one of the random access resources with a RSRP above the threshold for performing random access procedure 215 as a CBRA procedure. If there is not a random access resource with a RSRP satisfying a threshold RSRP, UE 115-a may select any random access resource of candidate random access resources for the CBRA procedure.
  • UE 115-a may determine a preamble to use for the random access procedure.
  • UE 115-a may send a first random access message to base station 105-a, and may receive a second message of a random access procedure from base station 105-a.
  • UE 115-a may select the particular random access preamble group (e.g., random access preambles group B) for the CBRA random access procedure.
  • a particular group of random access preambles is configured (e.g., random access preambles group B) , and if the third random access message size satisfies a third random access message size threshold (e.g., ra-Msg3SizeGroupA) , and the pathloss of the third random access message is less than a threshold pathloss message (e.g., PCMAX) of the serving cell performing the random access procedure
  • UE 115-a may select the particular random access preamble group (e.g., random access preambles group B) for the CBRA random access procedure.
  • UE 115-a may select the preamble from the particular random access preambles group (e.g., random access preamble group B) . Otherwise, UE 115-a may select the preamble from a second random access preamble group (e.g., random access preamble Group A) .
  • SDU control channel satellite data unit
  • UE 115-a may select the preamble from a second random access preamble group (e.g., random access preamble Group A) .
  • UE 115-a may retransmit the third random access message. In this case, UE 115-a may select the same group of random access preambles that UE 115-a used for the first message transmission (e.g., the random access preamble transmission) .
  • UE 115-a may randomly select a random access preamble from a set of random access preambles associated with the selected SSB and the select random access preamble group. UE 115-a may also set the preamble index to the selected random access preamble.
  • UE 115-a may perform random access procedure 215 using a CFRA or CBRA procedure, and using a resource other than the resource indicated in control signaling 210 in cases where UE 115-a is unable to detect the first synchronization signal resource indicated in control signaling 210. This process may improve efficiency and decrease retransmissions, as UE 115-a may be able to receive subsequent random access messages from base station 105-a, thereby completing the random access procedure more efficiently.
  • FIG. 3 illustrates an example of a decision tree 300 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • a UE 115 may use decision tree 300 to implement aspects of wireless communication systems 100 and 200.
  • the UE 115 may step through decision tree 300 to determine what type of random access procedure to use, including whether to use a CFRA or a CBRA.
  • a UE 115 may receive control signaling from a base station 105 indicating a first synchronization signal resource for the UE 115 to use for a CFRA random access procedure.
  • the control signaling may be a PDCCH order command.
  • a UE 115 may determine whether the first synchronization signal index (e.g., a SSB) for the CFRA indicated in the control signaling is not detected. If the UE 115 is unable to detect the CFRA synchronization signal index, then the UE 115 may move to decision 310. If the UE 115 is able to detect the first synchronization signal index for CFRA, the UE 115 may determine, at 315, to use the CFRA procedure based on the first synchronization signal index indicated in the PDCCH order. The UE 115 may then initiate the random access procedure by transmitting a first random access message.
  • the first synchronization signal index e.g., a SSB
  • the UE 115 may determine whether the CFRA resource for BFR that was previously configured in RRC is available. The UE 115 may determine whether the UE 115 received a RRC message indicating a CFRA resource for BFR, and the UE 115 may determine whether the resource is available. In cases where the UE 115 receives the RRC message indicating a CFRA resource for BFR, and the UE 115 determines that the CFRA resource for BFR is available, then the UE may trigger, at 325, the CFRA procedure, based on and using the CFRA resource for BFR. The UE 115 may then initiate the random access procedure by transmitting a first random access message.
  • the UE 115 may either not receive and RRC indicating the CFRA resource for BFR, or the UE 115 may receive the RRC message, but the UE 115 may determine that the CFRA resource for BFR is unavailable. In these cases, at 320, the UE 115 may trigger a CBRA procedure. The UE 115 may then initiate the random access procedure by transmitting a first random access message.
  • FIG. 4 illustrates an example of a process flow 400 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • process flow 400 may implement aspects of wireless communication systems 100 and 200.
  • Process flow 400 includes UE 115-b which may be an example of a UE 115 as described herein.
  • Process flow 400 also include base station 105 which may be an example of a base station 105 as described herein.
  • UE 115-b and base station 105-b may communicate in a wireless communications system.
  • UE 115-b may receive, from base station 105-b, control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the control signaling may be a PDCCH order command.
  • the first synchronization signal index may be a SSB index.
  • UE 115-b may also receive, from base station 105-b, configuration signaling indicating a set of CFRA resources associated with a BFR random access procedure.
  • the configuration signaling may be RRC signaling.
  • UE 115-b may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the selected resource other than the indicated first synchronization signal index for transmitting the first message of the random access procedure may be a random access occasion for transmitting a random access preamble message.
  • UE 115-b may determine one or more available resources from the set of CFRA resources associated with the BFR random access procedure based on a power measurement associated with the set of resources.
  • the random access procedure at 415 may be a CFRA resource
  • the selected resource may be a resource from the one or more available CFRA resources.
  • UE 115-b may determine that all resources from the set of CFRA resources associated with the BFR random access procedure are unavailable based on a power measurement associated with the set of resources.
  • the random access procedure at 415 may include a CBRA procedure, and the selected resource may be a resources selected based on the CBRA procedure (e.g., a randomly selected resource) .
  • UE 115-b may determine that CFRA resources associated with a BFR random access procedure are not configured.
  • the random access procedure at 415 may be a CBRA procedure, and the selected resource may be a resource selected based on the CBRA procedure.
  • UE 115-b may perform a random access procedure using the selected resource.
  • This random access procedure may include UE 115-b transmitting the first message of the random access procedure at 420.
  • base station 105-b may receive, from UE 115-b, the first message of a random access procedure using a selected resource other than the indicated first synchronization signaling index.
  • FIG. 5 shows a block diagram 500 of a device 505 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 505 may be an example of aspects of a UE 115 as described herein.
  • the device 505 may include a receiver 510, a communications manager 515, and a transmitter 520.
  • the device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to random access procedure resource selection, etc. ) . Information may be passed on to other components of the device 505.
  • the receiver 510 may be an example of aspects of the transceiver 820 described with reference to FIG. 8.
  • the receiver 510 may utilize a single antenna or a set of antennas.
  • the communications manager 515 may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure, select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and perform a random access procedure using the selected resource.
  • the communications manager 515 may be an example of aspects of the communications manager 810 described herein.
  • the communications manager 515 may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 515, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.
  • DSP digital signal processor
  • ASIC application-specific integrated circuit
  • FPGA field-programmable gate array
  • the communications manager 515 may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components.
  • the communications manager 515, or its sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure.
  • the communications manager 515, or its sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.
  • I/O input/output
  • the transmitter 520 may transmit signals generated by other components of the device 505.
  • the transmitter 520 may be collocated with a receiver 510 in a transceiver module.
  • the transmitter 520 may be an example of aspects of the transceiver 820 described with reference to FIG. 8.
  • the transmitter 520 may utilize a single antenna or a set of antennas.
  • the communications manager 515 described herein may be implemented as a chipset of a wireless modem, and the receiver 510 and the transmitter 520 may be implemented as sets of analog components (e.g., amplifiers, filters, phase shifters, antennas, etc. )
  • the wireless modem may obtain and decode signals from the receiver 510 over a receive interface, and may output signals for transmission to the transmitter 520 over a transmit interface.
  • the actions performed by the communications manager 515 as described herein may be implemented to realize one or more potential advantages.
  • One implementation may allow a UE 115 to save power and increase battery life, as the UE 115 may improve communication reliability by selecting random access resources.
  • the UE 115 may select random access resources that increase the likelihood of a successful random access procedure completion with a base station 105, thereby decreasing the amount of retransmissions by both the base station 105 and the UE 115. This may both save power and improve communications reliability at the UE 115.
  • FIG. 6 shows a block diagram 600 of a device 605 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 605 may be an example of aspects of a device 505, or a UE 115 as described herein.
  • the device 605 may include a receiver 610, a communications manager 615, and a transmitter 635.
  • the device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to random access procedure resource selection, etc. ) . Information may be passed on to other components of the device 605.
  • the receiver 610 may be an example of aspects of the transceiver 820 described with reference to FIG. 8.
  • the receiver 610 may utilize a single antenna or a set of antennas.
  • the communications manager 615 may be an example of aspects of the communications manager 515 as described herein.
  • the communications manager 615 may include a control component 620, a resource selection component 625, and a random access component 630.
  • the communications manager 615 may be an example of aspects of the communications manager 810 described herein.
  • the control component 620 may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the resource selection component 625 may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the random access component 630 may perform a random access procedure using the selected resource.
  • the transmitter 635 may transmit signals generated by other components of the device 605.
  • the transmitter 635 may be collocated with a receiver 610 in a transceiver module.
  • the transmitter 635 may be an example of aspects of the transceiver 820 described with reference to FIG. 8.
  • the transmitter 635 may utilize a single antenna or a set of antennas.
  • a processor of a UE 115 may efficiently operate the components described herein to save power and increase battery life of the UE 115.
  • the processor of the UE 115 may determine to select a random access resource different from a configured random access resource, based on whether the UE 115 may detect the configured resource. This determination may allow the UE 115 to improve communications reliability with a base station 105 by decreasing a number of retransmissions.
  • the processor of the UE 115 may operate the transmitter 635 to transmit a first random access message on the selected resource, thereby initiating a random access procedure with a higher likelihood of success, which may further improve efficiency of the UE 115.
  • FIG. 7 shows a block diagram 700 of a communications manager 705 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the communications manager 705 may be an example of aspects of a communications manager 515, a communications manager 615, or a communications manager 810 described herein.
  • the communications manager 705 may include a control component 710, a resource selection component 715, a random access component 720, a configuration component 725, and a measurement component 730. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
  • the control component 710 may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • control signaling includes a physical downlink control channel order command.
  • the resource selection component 715 may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the first synchronization signal index includes a SSB index.
  • the selected resource other than the indicated first synchronization signal index for transmitting the first message of a random access procedure includes a random access occasion for transmitting a random access preamble message.
  • the random access component 720 may perform a random access procedure using the selected resource.
  • the random access component 720 may determine one or more available resources from the set of CFRA resources associated with the BFR random access procedure based on a power measurement associated with the set of resources.
  • the random access component 720 may determine that CFRA resources associated with a BFR random access procedure are not configured.
  • the random access procedure includes a contention free random access procedure.
  • the selected resource includes a resource from the one or more available CFRA resources.
  • the random access procedure includes a CBRA procedure.
  • the selected resource includes a resource selected based on the CBRA procedure.
  • the configuration component 725 may receive configuration signaling indicating a set of CFRA resources associated with a BFR random access procedure.
  • the configuration signaling includes radio resource control signaling.
  • the measurement component 730 may determine all resources from the set of CFRA resources associated with the BFR random access procedure are unavailable based on a power measurement associated with the set of resources.
  • FIG. 8 shows a diagram of a system 800 including a device 805 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 805 may be an example of or include the components of device 505, device 605, or a UE 115 as described herein.
  • the device 805 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 810, an I/O controller 815, a transceiver 820, an antenna 825, memory 830, and a processor 840. These components may be in electronic communication via one or more buses (e.g., bus 845) .
  • buses e.g., bus 845
  • the communications manager 810 may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure, select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected, and perform a random access procedure using the selected resource.
  • the I/O controller 815 may manage input and output signals for the device 805.
  • the I/O controller 815 may also manage peripherals not integrated into the device 805.
  • the I/O controller 815 may represent a physical connection or port to an external peripheral.
  • the I/O controller 815 may utilize an operating system such as or another known operating system.
  • the I/O controller 815 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device.
  • the I/O controller 815 may be implemented as part of a processor.
  • a user may interact with the device 805 via the I/O controller 815 or via hardware components controlled by the I/O controller 815.
  • the transceiver 820 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 820 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 820 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 825. However, in some cases the device may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 830 may include RAM and ROM.
  • the memory 830 may store computer-readable, computer-executable code 835 including instructions that, when executed, cause the processor to perform various functions described herein.
  • the memory 830 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • BIOS basic I/O system
  • the processor 840 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 840 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into the processor 840.
  • the processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting random access procedure resource selection) .
  • the code 835 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 835 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory.
  • the code 835 may not be directly executable by the processor 840 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 9 shows a block diagram 900 of a device 905 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 905 may be an example of aspects of a base station 105 as described herein.
  • the device 905 may include a receiver 910, a communications manager 915, and a transmitter 920.
  • the device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to random access procedure resource selection, etc. ) . Information may be passed on to other components of the device 905.
  • the receiver 910 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12.
  • the receiver 910 may utilize a single antenna or a set of antennas.
  • the communications manager 915 may transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the communications manager 915 may be an example of aspects of the communications manager 1210 described herein.
  • the communications manager 915 may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 915, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.
  • code e.g., software or firmware
  • ASIC application-specific integrated circuit
  • the communications manager 915 may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components.
  • the communications manager 915, or its sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure.
  • the communications manager 915, or its sub-components may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.
  • I/O input/output
  • the transmitter 920 may transmit signals generated by other components of the device 905.
  • the transmitter 920 may be collocated with a receiver 910 in a transceiver module.
  • the transmitter 920 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12.
  • the transmitter 920 may utilize a single antenna or a set of antennas.
  • FIG. 10 shows a block diagram 1000 of a device 1005 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 1005 may be an example of aspects of a device 905, or a base station 105 as described herein.
  • the device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1030.
  • the device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .
  • the receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to random access procedure resource selection, etc. ) . Information may be passed on to other components of the device 1005.
  • the receiver 1010 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12.
  • the receiver 1010 may utilize a single antenna or a set of antennas.
  • the communications manager 1015 may be an example of aspects of the communications manager 915 as described herein.
  • the communications manager 1015 may include a control signaling component 1020 and a random access reception component 1025.
  • the communications manager 1015 may be an example of aspects of the communications manager 1210 described herein.
  • the control signaling component 1020 may transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure.
  • the random access reception component 1025 may receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the transmitter 1030 may transmit signals generated by other components of the device 1005.
  • the transmitter 1030 may be collocated with a receiver 1010 in a transceiver module.
  • the transmitter 1030 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12.
  • the transmitter 1030 may utilize a single antenna or a set of antennas.
  • FIG. 11 shows a block diagram 1100 of a communications manager 1105 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the communications manager 1105 may be an example of aspects of a communications manager 915, a communications manager 1015, or a communications manager 1210 described herein.
  • the communications manager 1105 may include a control signaling component 1110, a random access reception component 1115, and a configuration signaling component 1120. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
  • the control signaling component 1110 may transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure.
  • the first synchronization signal index includes a SSB index.
  • the random access reception component 1115 may receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the random access procedure includes a contention free random access procedure.
  • the selected resource includes a resource from the set of CFRA resources.
  • the random access procedure includes a CBRA procedure.
  • the selected resource includes a resource selected based on the CBRA procedure.
  • the selected resource other than the indicated first synchronization signal index for transmitting the first message of a random access procedure includes a random access occasion for transmitting a random access preamble message.
  • the configuration signaling component 1120 may transmit configuration signaling indicating a set of resources associated with a BFR random access procedure.
  • the configuration signaling includes radio resource control signaling.
  • control signaling includes a physical downlink control channel order command.
  • FIG. 12 shows a diagram of a system 1200 including a device 1205 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the device 1205 may be an example of or include the components of device 905, device 1005, or a base station 105 as described herein.
  • the device 1205 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1210, a network communications manager 1215, a transceiver 1220, an antenna 1225, memory 1230, a processor 1240, and an inter-station communications manager 1245. These components may be in electronic communication via one or more buses (e.g., bus 1250) .
  • buses e.g., bus 1250
  • the communications manager 1210 may transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure and receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the network communications manager 1215 may manage communications with the core network (e.g., via one or more wired backhaul links) .
  • the network communications manager 1215 may manage the transfer of data communications for client devices, such as one or more UEs 115.
  • the transceiver 1220 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above.
  • the transceiver 1220 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver.
  • the transceiver 1220 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.
  • the wireless device may include a single antenna 1225. However, in some cases the device may have more than one antenna 1225, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.
  • the memory 1230 may include RAM, ROM, or a combination thereof.
  • the memory 1230 may store computer-readable code 1235 including instructions that, when executed by a processor (e.g., the processor 1240) cause the device to perform various functions described herein.
  • a processor e.g., the processor 1240
  • the memory 1230 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.
  • the processor 1240 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) .
  • the processor 1240 may be configured to operate a memory array using a memory controller.
  • a memory controller may be integrated into processor 1240.
  • the processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting random access procedure resource selection) .
  • the inter-station communications manager 1245 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1245 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1245 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.
  • the code 1235 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications.
  • the code 1235 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1235 may not be directly executable by the processor 1240 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.
  • FIG. 13 shows a flowchart illustrating a method 1300 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the operations of method 1300 may be implemented by a UE 115 or its components as described herein.
  • the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 5 through 8.
  • a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.
  • the UE may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a control component as described with reference to FIGs. 5 through 8.
  • the UE may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a resource selection component as described with reference to FIGs. 5 through 8.
  • the UE may perform a random access procedure using the selected resource.
  • the operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a random access component as described with reference to FIGs. 5 through 8.
  • FIG. 14 shows a flowchart illustrating a method 1400 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the operations of method 1400 may be implemented by a UE 115 or its components as described herein.
  • the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 5 through 8.
  • a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.
  • the UE may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a control component as described with reference to FIGs. 5 through 8.
  • the UE may receive configuration signaling indicating a set of CFRA resources associated with a BFR random access procedure.
  • the operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a configuration component as described with reference to FIGs. 5 through 8.
  • the UE may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a resource selection component as described with reference to FIGs. 5 through 8.
  • the UE may perform a random access procedure using the selected resource.
  • the operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a random access component as described with reference to FIGs. 5 through 8.
  • FIG. 15 shows a flowchart illustrating a method 1500 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the operations of method 1500 may be implemented by a UE 115 or its components as described herein.
  • the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 5 through 8.
  • a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.
  • the UE may receive control signaling indicating a first synchronization signal index associated with performing a CFRA procedure.
  • the operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a control component as described with reference to FIGs. 5 through 8.
  • the UE may determine that CFRA resources associated with a BFR random access procedure are not configured.
  • the operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by a random access component as described with reference to FIGs. 5 through 8.
  • the UE may select a resource other than the indicated first synchronization signal index for transmitting a first message of a random access procedure based on a synchronization signal associated with the first synchronization signal index being undetected.
  • the operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by a resource selection component as described with reference to FIGs. 5 through 8.
  • the UE may perform a random access procedure using the selected resource.
  • the operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a random access component as described with reference to FIGs. 5 through 8.
  • FIG. 16 shows a flowchart illustrating a method 1600 that supports random access procedure resource selection in accordance with aspects of the present disclosure.
  • the operations of method 1600 may be implemented by a base station 105 or its components as described herein.
  • the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 9 through 12.
  • a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.
  • the base station may transmit control signaling indicating a first synchronization signal index associated with transmitting a first message of a CFRA procedure.
  • the operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a control signaling component as described with reference to FIGs. 9 through 12.
  • the base station may receive a first message of a random access procedure using a selected resource other than the indicated first synchronization signal index.
  • the operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a random access reception component as described with reference to FIGs. 9 through 12.
  • LTE, LTE-A, LTE-A Pro, or NR may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks.
  • the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.
  • UMB Ultra Mobile Broadband
  • IEEE Institute of Electrical and Electronics Engineers
  • Wi-Fi Institute of Electrical and Electronics Engineers
  • WiMAX IEEE 802.16
  • IEEE 802.20 Flash-OFDM
  • Information and signals described herein may be represented using any of a variety of different technologies and techniques.
  • data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine.
  • a processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .
  • the functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
  • Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • a non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.
  • non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • flash memory compact disk (CD) ROM or other optical disk storage
  • CD compact disk
  • magnetic disk storage or other magnetic storage devices or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer,
  • Disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

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Abstract

L'invention concerne des procédés, des systèmes et des dispositifs de communication sans fil. Un équipement utilisateur (UE) peut communiquer avec une station de base dans un système de communication sans fil. L'UE peut effectuer une procédure d'accès aléatoire pour communiquer avec la station de base. L'UE peut recevoir une signalisation de commande indiquant un premier indice de signal de synchronisation associé à la réalisation d'une procédure d'accès aléatoire sans contention. L'UE peut sélectionner une ressource autre que le premier indice de signal de synchronisation indiqué pour transmettre un premier message d'une procédure d'accès aléatoire d'après un signal de synchronisation associé au premier indice de signal de synchronisation qui n'est pas détecté. L'UE peut ensuite réaliser la procédure d'accès aléatoire à l'aide de la ressource sélectionnée.
PCT/CN2020/088711 2020-05-06 2020-05-06 Sélection de ressources de procédure d'accès aléatoire WO2021223091A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
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