Performing random access procedure in wireless communication system

Abstract

A method is disclosed that includes initiating a random access (RA) procedure for a bandwidth portion (BWP) by reconfiguration with synchronization, initiating reconfiguration with synchronization for recovery without using a low layer triggered mobility (LTM) candidate configuration, performing the 4-step RA when dedicated contention-free RA resources for the 4-step RA are configured at the BWP, and performing the 4-step RA when dedicated contention-free RA resources for the 4-step RA are configured at the BWP. When the BWP is not configured with the special competition-free RA resource of the four-step RA, executing the two-step RA when the BWP is configured with the special competition-free RA resource of the two-step RA, and executing the four-step RA when the BWP is not configured with the special competition-free RA resource of the two-step RA; when the LTM candidate configuration is used to initiate reconfiguration with synchronization for recovery: when the BWP configures the RA resource of the two-step RA: when the BWP does not configure the RA resource of the four-step RA, the two-step RA is performed, when the BWP configures the RA resource of the four-step RA: when the measurement RSRP of the downlink path loss reference is higher than the message A threshold, the two-step RA is performed, and when the measurement RSRP of the downlink path loss reference is not higher than the message A threshold, the RA resource of the four-step RA is performed. And executing the step 4 RA.

Description

Technical Field

[0001] The present disclosure generally relates to performing a random access procedure. Background Art

[0002] As wireless systems evolve, there are more and more scenarios in which performing a random access (RA) procedure for a user equipment (UE) is desirable. However, many of the scenarios involving random access procedures have different requirements and priorities. Furthermore, there are various ways in which random access can be performed, such as a two-step RA-type procedure, a four-step RA-type procedure, a contention-based RA procedure, a contention-free RA procedure, and so on. It is important for a UE to be able to select the correct type of RA procedure and the correct resources to use for the RA procedure based on the purpose of initiating the RA procedure. Summary of the Invention

[0003] Various aspects of examples of the invention are set out in the claims.

[0004] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for initiating a random access (RA) procedure for a bandwidth part (BWP) by reconfiguration with synchronization, determining whether to initiate reconfiguration with synchronization for recovery using a lower layer triggered mobility (LTM) candidate without using an LTM candidate configuration, determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, performing a 4-step RA if the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, and, if an active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type: determining whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, performing a 2-step RA if the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. , in case the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, perform a 4-step RA, in case reconfiguration with synchronization is initiated for recovery using LTM candidate configuration: determine whether the BWP is configured with RA resources for the 2-step RA type, in case the BWP is configured with RA resources for the 2-step RA type: determine whether the BWP is configured with RA resources for the 4-step RA type, in case the BWP is not configured with RA resources for the 4-step RA type random access, perform a 2-step RA, in case the BWP is configured with RA resources for the 4-step RA type: determine whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold, in case the measured RSRP of the downlink path loss reference is higher than the message A threshold, perform a 2-step RA, and in case the measured RSRP of the downlink path loss reference is not higher than the message A threshold, perform a 4-step RA.

[0005] In at least one example embodiment, the dedicated contention-free RA resources are received in a rach-configDedicated information element.

[0006] In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with common RA resources for the 2-step RA type.

[0007] In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for the 4-step RA type.

[0008] In at least one example embodiment, cases where reconfiguration with synchronization is initiated for recovery using the LTM candidate configuration include cases where a previous reconfiguration with synchronization failed and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

[0009] In at least one example embodiment, performing the 2-step RA includes setting the RA type to be performed to a 2-step RA type, and performing the RA procedure based on the set RA type.

[0010] In at least one example embodiment, performing a 2-step RA includes selecting an RA resource set and performing an RA procedure based on an RA type specified by the selected RA resource set.

[0011] In at least one example embodiment, performing the 4-step RA includes setting the RA type to be performed to the 4-step RA type, and performing the RA procedure based on the set RA type.

[0012] In at least one example embodiment, performing a 4-step RA includes selecting an RA resource set and performing an RA procedure based on an RA type specified by the selected RA resource set.

[0013] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for initiating a random access (RA) procedure for a bandwidth part (BWP), determining whether the RA procedure is initiated by a PDCCH command, and if the RA procedure is initiated by the PDCCH command, performing a 4-step RA using the RA resources indicated by the PDCCH command, and if the RA procedure is not initiated by the PDCCH command: determining that the RA procedure is initiated by a reconfiguration with synchronization, determining whether to use a low layer triggered mobility (LTM) candidate to initiate the reconfiguration with synchronization for recovery, and if the reconfiguration with synchronization for recovery is not initiated using an LTM candidate configuration: determining whether the BWP is configured with a dedicated contention-free RA resource for a 4-step RA type, and if the BWP is configured with a dedicated contention-free RA resource for a 4-step RA type, performing a 4-step RA, and if the active BWP is not configured with a dedicated contention-free RA resource for a 4-step RA type: determining whether the BWP is configured for a 2-step RA type dedicated contention-free RA resources for the 2-step RA type, in case the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, perform 2-step RA, in case the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, perform 4-step RA, in case reconfiguration with synchronization is initiated for recovery using LTM candidate configuration: determine whether the BWP is configured with RA resources for the 2-step RA type, in case the BWP is configured with RA resources for the 2-step RA type: determine whether the BWP is configured with RA resources for the 4-step RA type, in case the BWP is not configured with RA resources for the 4-step RA type random access, perform 2-step RA, in case the BWP is configured with RA resources for the 4-step RA type: determine whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold, in case the measured RSRP of the downlink path loss reference is higher than the message A threshold, perform 2-step RA, and in case the measured RSRP of the downlink path loss reference is not higher than the message A threshold, perform 4-step RA.

[0014] In at least one example embodiment, the PDCCH order is downlink control information (DCI).

[0015] In at least one example embodiment, the downlink control information is DCI scrambled by a cell radio network temporary identifier (C-RNTI), and the DCI includes a frequency domain resource allocation field with each bit set to a value of 1.

[0016] In at least one exemplary embodiment, scrambling the DCI with the C-RNTI and setting each bit of the frequency domain allocation field to a value of 1 signifies that the DCI is initiating an RA procedure via a PDCCH command.

[0017] In at least one example embodiment, the DCI includes a cell indicator field.

[0018] In at least one example embodiment, the DCI is DCI format 1_0.

[0019] In at least one example embodiment, where the RA procedure is initiated by a PDCCH order, performing the 4-step RA using the RA resources indicated by the PDCCH order includes selecting a set of RA resources configured in an early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field, and performing the 4-step RA includes performing the 4-step RA using the selected RA resources.

[0020] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for initiating a random access (RA) procedure for a bandwidth part (BWP), determining whether the RA procedure is initiated by a reconfiguration with synchronization, and in a case where the RA procedure is initiated by a reconfiguration with synchronization: determining whether the reconfiguration with synchronization for recovery is initiated using a lower layer triggered mobility (LTM) candidate, and in a case where the reconfiguration with synchronization for recovery is not initiated using an LTM candidate configuration: determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, and in a case where the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, performing a 4-step RA, and in a case where an active BWP is not configured with dedicated contention-free RA resources for a 4-step RA type: determining whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, and in a case where the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, performing a 2-step RA, and in a case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type In case of dedicated contention-free RA resources, perform 4-step RA. In case of initiating reconfiguration with synchronization for recovery using LTM candidate configuration: determine whether the BWP is configured with RA resources for 2-step RA type. In case the BWP is configured with RA resources for 2-step RA type: determine whether the BWP is configured with RA resources for 4-step RA type. In case the BWP is not configured with RA resources for 4-step RA type random access, perform 2-step RA. In case the BWP is configured with RA resources for 4-step RA type: determine whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold. In case the measured RSRP of the downlink path loss reference is higher than the message A threshold, perform 2-step RA. In case the measured RSRP of the downlink path loss reference is not higher than the message A threshold, perform 4-step RA. In case the RA procedure is not initiated by reconfiguration with synchronization: determine whether the RA procedure is initiated by the LTM cell handover media access control (MAC) control element (CE). Determine the LTM cell handover MAC. Whether the CE indicates contention-free random access resources. If the LTM cell handover MAC CE indicates contention-free random access resources, perform 4-step RA using the contention-free resources indicated by the LTM cell handover MAC CE. If the LTM cell handover MAC CE does not indicate contention-free random access resources: determine whether the BWP is configured with RA resources for 2-step RA type. If the BWP is configured with RA resources for 2-step RA type: determine whether the BWP is configured with RA resources for 4-step RA type. If the BWP is not configured with RA resources for 4-step RA type random access, perform 2-step RA.In case the BWP is configured with RA resources for a 4-step RA type: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is higher than a Message A threshold, performing a 2-step RA if the measured RSRP of the downlink path loss reference is higher than the Message A threshold, and performing a 4-step RA if the measured RSRP of the downlink path loss reference is not higher than the Message A threshold.

[0021] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for initiating a random access (RA) procedure for a bandwidth part (BWP), determining whether the RA procedure is initiated by a PDCCH command, and if the RA procedure is initiated by the PDCCH command, performing a four-step RA using RA resources indicated by the PDCCH command, and if the RA procedure is not initiated by the PDCCH command: determining whether the RA procedure is initiated by a reconfiguration with synchronization, and if the RA procedure is initiated by a reconfiguration with synchronization: Determine whether a reconfiguration with synchronization for recovery was initiated using a Low Layer Triggered Mobility (LTM) candidate. In case a reconfiguration with synchronization for recovery was not initiated using an LTM candidate configuration: Determine whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type. In case the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, perform a 4-step RA. In case the active BWP is not configured with dedicated contention-free RA resources for a 4-step RA type: Determine whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type. In case the BWP is configured with dedicated contention-free RA resources for a 2-step RA type In case of dedicated contention-free RA resources of type A, perform 2-step RA. In case the BWP is not configured with dedicated contention-free RA resources for 2-step RA type, perform 4-step RA. In case reconfiguration with synchronization for recovery is initiated using LTM candidate configuration: determine whether the BWP is configured with RA resources for 2-step RA type. In case the BWP is configured with RA resources for 2-step RA type: determine whether the BWP is configured with RA resources for 4-step RA type. In case the BWP is not configured with RA resources for 4-step RA type random access, perform 2-step RA. In case the BWP In a case where RA resources for a 4-step RA type are configured: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is higher than a message A threshold; if the measured RSRP of the downlink path loss reference is higher than the message A threshold, performing a 2-step RA; if the measured RSRP of the downlink path loss reference is not higher than the message A threshold, performing a 4-step RA; in a case where the RA procedure is not initiated by a reconfiguration with synchronization: determining whether the RA procedure is initiated by an LTM cell handover media access control (MAC) control element (CE); determining whether the LTM cell handover MAC CE indicates a contention-free random access resource; if the LTM cell handover MAC CE indicates a contention-free random access resource, performing a 4-step RA using the contention-free resource indicated by the LTM cell handover MAC CE; in a case where the LTM cell handover MAC CE does not indicate a contention-free random access resource: determining whether the BWP is configured with RA resources for a 2-step RA type;In case the BWP is configured with RA resources for a 2-step RA type: determining whether the BWP is configured with RA resources for a 4-step RA type, in case the BWP is not configured with RA resources for a 4-step RA type random access, performing a 2-step RA, in case the BWP is configured with RA resources for a 4-step RA type: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is higher than a Message A threshold, in case the measured RSRP of the downlink path loss reference is higher than the Message A threshold, performing a 2-step RA, and in case the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, performing a 4-step RA. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a more complete understanding of embodiments of the present invention, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 is a block diagram illustrating an apparatus according to at least one example embodiment,

[0024] Figure 2 is a block diagram illustrating a wireless communication system according to at least one example embodiment,

[0025] Figure 3 is a diagram illustrating a protocol stack according to at least one example embodiment,

[0026] Figure 4A-4B is a diagram illustrating a random access procedure according to at least one example embodiment,

[0027] Figure 5A-5B is a flowchart illustrating activities associated with performing random access according to at least one example embodiment, and

[0028] Figures 6-10 is a flow diagram illustrating activities associated with a random access procedure according to at least one example embodiment. DETAILED DESCRIPTION

[0029] By referring to the accompanying drawings Figures 1 to 10 , you can understand the embodiments of the present invention and its potential advantages.

[0030] Some embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. The various embodiments of the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. As used herein, the terms "data," "content," "information," and similar terms may be used interchangeably to refer to data capable of being transmitted, received, and / or stored in accordance with embodiments of the present invention. Accordingly, the use of any such terms should not be taken as limiting the spirit and scope of embodiments of the present invention.

[0031] Additionally, as used herein, the term "circuitry" refers to (a) hardware-only circuit implementations (e.g., implementations in analog circuitry and / or digital circuitry); (b) a combination of circuitry and (one or more) computer program products, the (one or more) computer program products comprising software and / or firmware instructions stored on one or more computer-readable memories that work together to cause the device to perform one or more functions described herein; and (c) circuitry, such as, for example, microprocessor(s) or a portion of a microprocessor(s), that requires software or firmware for operation even if the software or firmware is not physically present. This definition of "circuitry" applies to all uses of the term herein, including in any claims. As a further example, as used herein, the term "circuitry" also includes implementations comprising one or more processors and / or portion(s) thereof and accompanying software and / or firmware. As another example, as used herein, the term "circuitry" also includes, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone, or similar integrated circuits in servers, cellular network devices, other network devices, and / or other computing devices.

[0032] As defined herein, "non-transitory computer-readable media," which refers to physical media (eg, volatile or non-volatile memory devices), can be distinguished from "transitory computer-readable media," which refers to electromagnetic signals.

[0033] Figure 11 is a block diagram illustrating an apparatus (such as electronic apparatus 100) according to at least one example embodiment. However, it should be understood that the electronic apparatus illustrated and described below is merely illustrative of an electronic apparatus that may benefit from embodiments of the present invention and, therefore, should not be used to limit the scope of the present invention. Although electronic apparatus 100 is illustrated and will be described below for purposes of example, other types of electronic apparatuses may readily employ embodiments of the present invention. Electronic apparatus 100 may be a network node (such as a user equipment (UE) or a base station) and / or may be a personal digital assistant (PDA), a pager, a mobile computer, a desktop computer, a television, a gaming device, a laptop computer, a tablet computer, a media player, a camera, a video recorder, a mobile phone, a global positioning system (GPS) device, a car, a phone booth, an electronic table, and / or any other type of electronic system. In addition, the apparatus of at least one example embodiment need not be an entire electronic apparatus, but may be a component or group of components of an electronic apparatus in other example embodiments. For example, the apparatus may be an integrated circuit, a collection of integrated circuits, and / or the like.

[0034] Furthermore, devices can readily employ embodiments of the present invention regardless of their intent to provide mobility. In this regard, even though embodiments of the present invention may be described in conjunction with mobile applications, it should be understood that embodiments of the present invention may be utilized in conjunction with a wide variety of other applications both within the mobile communications industry and outside of the mobile communications industry. For example, the device may be at least a portion of a non-portable device such as a large-screen television, an electronic table, a telephone booth, an automobile, and / or the like.

[0035] In at least one example embodiment, the electronic device 100 includes a processor 110 and a memory 140. The processor 110 can be any type of processor, controller, embedded controller, processor core, and / or the like. In at least one example embodiment, the processor 110 utilizes computer program code to cause the device to perform one or more actions. The memory 140 can include volatile memory, such as volatile random access memory (RAM) including a cache area for temporarily storing data, and / or other memory, such as non-volatile memory, which can be embedded and / or removable. The non-volatile memory can include EEPROM, flash memory, and / or the like. The memory 140 can store any of a number of pieces of information and data. The electronic device 100 can use this information and data to implement one or more functions of the electronic device 100, such as the functions described herein. In at least one example embodiment, the memory 140 includes computer program code such that the memory and the computer program code are configured to work together with the processor to cause the device to perform one or more actions described herein.

[0036] The electronic device 100 may also include a transceiver 120. In at least one example embodiment, the transceiver 120 is coupled to one or more antennas 130. In at least one example embodiment, the processor 110 provides signals to and / or receives signals from the transceiver 120. The signals may include signaling information according to a communication interface standard, user speech, received data, user-generated data, and / or the like. The transceiver 120 may operate using one or more air interface standards, communication protocols, modulation types, and access types. By way of illustration, the electronic transceiver 120 may operate in accordance with second generation (2G) wireless communication protocols IS-136 (Time Division Multiple Access (TDMA)), Global System for Mobile Communications (GSM), and IS-95 (Code Division Multiple Access (CDMA)), in accordance with third generation (3G) wireless communication protocols such as Universal Mobile Telecommunications System (UMTS), CDMA2000, Wideband CDMA (WCDMA), and Time Division Synchronous CDMA (TD-SCDMA), and / or in accordance with fourth generation (4G) wireless communication protocols such as LTE, fifth generation (5G) protocols such as New Radio (NR) wireless networking protocols such as 802.11, short range wireless protocols such as Bluetooth, and / or the like.

[0037] The processor 110 may include components (such as circuits) for implementing audio, video, communication, navigation, logic functions, and / or the like, as well as for implementing embodiments of the present invention, including, for example, one or more of the functions described herein. For example, the processor 110 may include components such as a digital signal processor device, a microprocessor device, various analog-to-digital converters, digital-to-analog converters, processing circuits, and other supporting circuitry for performing various functions, including, for example, one or more of the functions described herein. The device may perform control and signal processing functions for the electronic device 100 between these devices based on their respective capabilities. Thus, the processor 110 may include functionality for encoding and interleaving messages and data prior to modulation and transmission. The processor 110 may additionally include an internal voice encoder and may include an internal data modem. Further, the processor 110 may include functionality for operating one or more software programs, which may be stored in memory and, among other things, enable the processor 110 to implement at least a portion of an embodiment, including, for example, one or more of the functions described herein. For example, the processor 110 may operate a connectivity program, such as a conventional internet browser. For example, the connectivity program may allow the electronic device 100 to transmit and receive Internet content, such as location-based content and / or other web content, in accordance with: Transmission Control Protocol (TCP), Internet Protocol (IP), User Datagram Protocol (UDP), Internet Message Access Protocol (IMAP), Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), Wireless Application Protocol (WAP), Hypertext Transfer Protocol (HTTP), and / or the like.

[0038] The electronic device 100 may include a user interface for providing output and / or receiving input. The electronic device 100 may include an output device, which may include an audio output device (such as a ringer, headphones, or a speaker), a tactile output device (such as a vibration transducer, an electronic deformable surface, or an electronic deformable structure), or a visual output device (such as a display and / or a light). The electronic device may include an input device such as a light sensor, a proximity sensor, a microphone, a touch sensor, a force sensor, a button, a keyboard, a motion sensor, a magnetic field sensor, a camera, and / or the like. In at least one example embodiment, the device receives an indication of an input. The device may receive the indication from a sensor, a driver, a separate device, and / or the like. The information indicative of the input may include information conveying the following information: indicating the input, indicating an aspect of the input, indicating the occurrence of the input, and / or the like.

[0039] Figure 2An example of a wireless communication system 200 according to at least one example embodiment is illustrated. The wireless communication system 200 includes one or more base stations 202, a core network 203, and one or more user equipment (UEs), such as UE 201 and / or UE 204. In some examples, the wireless communication system 200 may be a Long Term Evolution (LTE), an Advanced LTE (LTE-A) network, a New Radio (NR) network, or the like. In some cases, the wireless communication system 200 may support enhanced broadband communications, ultra-reliable (i.e., mission-critical) communications, low-latency communications, and communications with low-cost and low-complexity devices. To improve the reliability of some communications (e.g., ultra-reliable low-latency communications (URLLC) packets), the wireless communication system 200 may be configured to generate and transmit duplicate packets. In such a duplicate system, a transmitting device (e.g., base station 202, UE 201, or UE 204) may duplicate packets. The original packet and the duplicated packet may be transmitted to a receiving device (e.g., base station 202, UE 201, or UE 204). Transmitting multiple packets including the same information may improve the likelihood that a receiving device will receive the information included in the multiple packets.

[0040] One or more base stations 202 can wirelessly communicate with one or more UEs (e.g., UE 201 or UE 204) via one or more base station antennas. Each base station 202 provides communication coverage for a corresponding geographic coverage area. The communication link in the wireless communication system 200 can include an uplink transmission from the UE to the base station 202, or a downlink transmission from the base station 202 to the UE. According to various techniques, control information and data can be multiplexed on an uplink channel or a downlink. For example, time division multiplexing (TDM) technology, frequency division multiplexing (FDM) technology, or a hybrid TDM-FDM technology can be used to multiplex control information and data on a downlink channel. In some examples, the control information transmitted during a transmission time interval (TTI) of the downlink channel can be distributed in a cascaded manner between different control regions (e.g., between a common control region and one or more UE-specific control regions).

[0041] Throughout the wireless communication system 200, multiple UEs may be dispersed, and each UE may be fixed or mobile. A UE may also be referred to as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE may also be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a personal electronic device, a handheld device, a personal computer, a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, a machine type communication (MTC) device, an appliance, an automobile, etc.

[0042] In some cases, a UE may also be able to communicate directly with other UEs using sidelink communications (e.g., using a point-to-point (P2P) or device-to-device (D2D) protocol). Figure 2 An example of such communication between UE 201 and UE 204 is provided. One or more of the UEs in the group utilizing sidelink communication may be within the coverage area of ​​a cell. Other UEs in such a group may be outside the coverage area of ​​the cell or otherwise unable to receive transmissions from base station 202. In some cases, the group of UEs communicating via sidelink communication may utilize a one-to-many (1:M) system, where each UE transmits to all other UEs in the group. In some cases, base station 202 facilitates scheduling of resources for sidelink communication. In other cases, sidelink communication is implemented independently of base station 202.

[0043] In some cases, UE 204 may operate as a relay UE for UE 201. For example, instead of the UE communicating directly with base station 202, UE 204 may be configured to operate as a relay such that UE 201 communicates with base station 202 via communications that pass directly through UE 204. For example, UE 204 may operate as a Layer 2 (L2) UE-to-Network (U2N) relay.

[0044] Some UEs, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines, i.e., machine-to-machine (M2M) communication. M2M or MTC may refer to data communication technologies that allow devices to communicate with each other or with base stations without human intervention. For example, M2M or MTC may refer to communications from devices that have integrated sensors or meters to measure or capture information and relay that information to a central server or application that can utilize the information or present it to humans interacting with the program or application. Some UEs may be designed to collect information or enable automated behavior of machines. 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 service charging.

[0045] In some cases, MTC devices can operate at a reduced peak rate using half-duplex (one-way) communication. MTC devices can also be configured to enter a power-saving "deep sleep" mode when not engaged in active communications. In some cases, MTC or IoT devices can be designed to support mission-critical functions, and the wireless communication system can be configured to provide ultra-reliable communication for these functions.

[0046] Base station 202 can communicate with core network 203 and one or more other base stations. For example, the base station can be connected to core network 203 via an incoming backhaul link (e.g., S1, etc.). The base stations can communicate with each other directly or indirectly (e.g., through core network 203) via other backhaul links (e.g., X2, etc.). The base station can perform radio configuration and scheduling for communicating with the UE, or can operate under the control of a base station controller (not shown). In some examples, base station 202 can be a macro cell, a small cell, a hotspot, and / or the like. The base station can also be referred to as an evolved NodeB (NB), such as an eNB, gNB, and / or the like.

[0047] The base station 202 can be connected to the core network 203 via an S1 interface. The core network can be an evolved packet core (EPC), which can include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME can be a control node that handles signaling between the UE 201 and the EPC. All user Internet Protocol (IP) packets can be transmitted through the S-GW, which itself can be connected to the P-GW. The P-GW can provide IP address allocation and other functions. The P-GW can be connected to the network operator's IP services. The operator's IP services can include the Internet, intranet, IP multimedia subsystem (IMS), and packet switched (PS) streaming services.

[0048] The core network 203 may provide user authentication, access authorization, tracking, IP connectivity, and other access, routing, or mobility functions. At least some of the network devices, such as the base station 202, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC). Each access network entity may communicate with a number of UEs via a number of other access network transport entities, each of which may be an example of a smart radio head or a transmission / reception point (TRP). In some configurations, the various functions of each access network entity or base station may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., the base station 202).

[0049] The wireless communication system 200 can operate in the ultra-high frequency (UHF) frequency region, using a frequency band from 700 MHz to 2600 MHz (2.6 GHz), although some networks (e.g., wireless local area networks (WLANs)) can use frequencies up to 4 GHz. This region can also be referred to as the decimeter band, as wavelengths range in length from approximately one decimeter to one meter. UHF waves may primarily propagate via line of sight and may be blocked by buildings and environmental features. However, the waves can penetrate walls sufficiently to provide service to UEs located indoors. Compared to transmissions using the lower frequencies (and longer waves) in the high frequency (HF) or very high frequency (VHF) portions of the spectrum, UHF wave transmissions are characterized by smaller antennas and a shorter range (e.g., less than 100 km). In some cases, the wireless communication system 200 can also utilize the extremely high frequency (EHF) portion of the spectrum (e.g., from 30 GHz to 300 GHz). This region can also be referred to as the millimeter band, as wavelengths range in length from approximately one millimeter to one centimeter. Consequently, EHF antennas can be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate the use of an antenna array within the UE 201 (eg, for directional beamforming).However, EHF transmissions may be subject to even greater atmospheric attenuation and a shorter range than UHF transmissions.

[0050] Thus, the wireless communication system 200 can support millimeter wave (mmW) communications between UEs and base stations. Devices operating in the mmW or EHF bands can have multiple antennas to allow beamforming. That is, the base station 202 can use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE 201. Beamforming (which may also be referred to as spatial filtering or directional transmission) is a signal processing technique that can be used at a transmitter (e.g., a base station) to shape and / or steer the total antenna beam in the direction of a target receiver (e.g., a UE). This can be achieved by combining elements in the antenna array in such a way that signals transmitted at a specific angle experience constructive interference, while other signals experience destructive interference.

[0051] A cell can operate within a total channel bandwidth. In some cases, it may be desirable for a cell to have a structure that refers to different parts of the total channel bandwidth, such as bandwidth parts (BWPs). Such a structure allows the configuration information of a cell to be common within a BWP and different across different BWPs. For example, it may be desirable for a cell to have two BWPs so that time-frequency resources are configured differently between the two BWPs. In addition, such a structure allows for a smooth transition between the configuration for a BWP and the configuration for a different BWP simply by indexing the correct BWP and referencing the configuration information of the indexed BWP. In this way, each BWP can have its own configuration information for managing multiple aspects of communication, such as physical layer resources, MAC resources, RRC resources, etc.

[0052] A multiple-input, multiple-output (MIMO) wireless system uses a transmission scheme between a transmitter (e.g., a base station) and a receiver (e.g., a UE) in which both the transmitter and the receiver are equipped with multiple antennas. Some portions of the wireless communication system 200 may use beamforming. For example, the base station 202 may have an antenna array having rows and columns of antenna ports that the base station may use for beamforming in its communication with the UE 201. The signal may be transmitted multiple times in different directions (e.g., each transmission may be beamformed differently). The mmW receiver (e.g., a UE) may attempt multiple beams (e.g., antenna subarrays) while receiving synchronization signals.

[0053] In some cases, the antennas of base station 202 or UE 201 may be located within one or more antenna arrays that may support beamforming or MIMO operations. One or more base station antennas or antenna arrays may be collocated at an antenna assembly, such as an antenna tower. In some cases, the antennas or antenna arrays associated with base station 202 may be located at different geographic locations. Base station 202 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with UE 201.

[0054] In some cases, the wireless communication system 200 can be a packet-based network operating according to a layered protocol stack. In the user plane, the communication at the bearer layer or PDCP layer can be IP-based. In some cases, the RLC layer can perform packet segmentation and reassembly to communicate through logical channels. The media access control (MAC) layer can perform priority processing and multiplex logical channels into transport channels. The MAC layer can also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the UE 201 and the network equipment or core network 203 that supports the radio bearer of user plane data. At the physical (PHY) layer, the transport channel can be mapped to the physical channel.

[0055] Time intervals in LTE or NR can be expressed in multiples of a basic time unit (which can be a sampling period of Ts = 1 / 30,720,000 seconds). Time resources can be organized according to radio frames of length 10 ms (Tf = 307200Ts), which can be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame can include ten 1 ms subframes numbered from zero to nine. The subframe can also be divided into two 0.5 ms time slots, each of which contains six or seven modulation symbol periods (depending on the length of the cyclic prefix pre-appended to each symbol). In addition to the cyclic prefix, each symbol contains 2048 sampling periods. In some cases, the subframe can be the smallest scheduling unit, also known as TTI. In other cases, the TTI can be shorter than the subframe or can be dynamically selected (for example, in a short TTI burst or in a selected component carrier using a short TTI).

[0056] A resource element may consist of one symbol period and one subcarrier (e.g., a 15 kHz frequency range). A resource block may contain twelve consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each orthogonal frequency division multiplexing (OFDM) symbol, may contain seven consecutive OFDM symbols in the time domain (one slot), or 84 resource elements. The number of bits carried by each resource element may depend on the modulation scheme (the configuration of symbols that may be selected during each symbol period). Therefore, the more resource blocks a UE receives and the higher the modulation scheme, the higher the data rate may be.

[0057] The wireless communication system 200 may support operation on multiple cells or carriers, a feature that may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), layer, channel, etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably herein. The UE 201 may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation. Carrier aggregation may be used with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers.

[0058] In some cases, the wireless system 200 can utilize both licensed radio spectrum bands and unlicensed radio spectrum bands. For example, the wireless system 200 can adopt LTE license-assisted access (LTE-LAA) or LTE unlicensed (LTE U) radio access technology or NR technology in an unlicensed band such as the 5Ghz industrial, scientific and medical (ISM) band. When operating in an unlicensed radio spectrum band, wireless devices such as base station 202 and UE 201 can adopt a listen-before-talk (LBT) process to ensure that the channel is unoccupied before transmitting data. In some cases, operations in the unlicensed band can be based on a CA configuration in combination with CCs operating in the licensed band. Operations in the unlicensed spectrum can include downlink transmissions, uplink transmissions, or both. The duplexing in the unlicensed spectrum can be based on FDD, TDD, or a combination of the two.

[0059] Figure 3 is a diagram illustrating a protocol stack 300 according to at least one example embodiment. Figure 3 The examples are merely examples and do not necessarily limit the scope of the claims.

[0060] In at least one example embodiment, the physical (PHY) layer 304 provides information transfer services to higher layers using physical channels. The PHY layer 304 can be connected to the media access control (MAC) layer 303 located on the higher layer via a transport channel. Data can be transported between the MAC layer 303 and the PHY layer 304 via the transport channel. Data can be transported between the physical layer on the transmission side and the physical layer on the reception side via the physical channel. The physical channel uses time and frequency as radio resources. In some cases, the physical channel is modulated using an orthogonal frequency division multiple access (OFDMA) scheme in the downlink and a single carrier frequency division multiple access (SC-FDMA) scheme in the uplink.

[0061] In at least one exemplary embodiment, the MAC layer 303 provides services to the higher-layer radio link control (RLC) layer 302 via logical channels. The RLC layer 302 of the second layer supports reliable data transmission. The functions of the RLC layer 302 can be implemented by the functional blocks of the MAC layer 303. The packet data convergence protocol (PDCP) layer 301 performs a header compression function to reduce unnecessary control information in order to efficiently transmit Internet Protocol (IP) packets, such as IP version 4 (IPv4) packets or IP version 6 (IPv6) packets, over a radio interface having a relatively small bandwidth.

[0062] In at least one exemplary embodiment, the PDCP layer 301 is implemented by way of a PDCP entity that performs various actions of the PDCP layer. In this manner, an operating network node includes one or more PDCP entities for performing PDCP layer activities. In operation, the PDCP entity receives data from higher layers for transmission in PDCP service data units (SDUs). The PDCP entity performs various operations, such as header compression, uplink data compression, integrity protection, ciphering, and / or the like, on the PDCP SDUs it receives for transmission from higher layers. The PDCP entity performs these operations on the received PDCP SDUs to generate PDCP packet data units (PDUs), which are transmitted by way of the PDCP entity sending the PDCP SDUs to lower layers for transmission.

[0063] In at least one exemplary embodiment, the RLC layer 302 is implemented as an RLC entity that performs various RLC layer actions. In this manner, an operating network node includes one or more RLC entities for performing RLC layer activities. In operation, an RLC entity receives data from a higher layer in an RLC SDU for transmission. The RLC entity performs various operations on the RLC SDUs it receives for transmission from a higher layer, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The RLC entity performs these operations on the received RLC SDUs to generate an RLC PDU, which is transmitted by the RLC entity sending the RLC SDUs to a lower layer for transmission.

[0064] In at least one example embodiment, the MAC layer 303 is implemented by way of a MAC entity that performs various MAC layer actions. In this manner, an operating network node includes one or more MAC entities for performing MAC layer activities. In operation, the MAC entity receives data for transmission from higher layers in MAC SDUs. The MAC entity performs various operations on the MAC SDUs it receives for transmission from higher layers, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The MAC entity performs these operations on the received MAC SDUs to generate a MAC PDU, which is transmitted by the MAC entity sending the MAC SDUs to lower layers for transmission.

[0065] In many cases, it may be desirable for a UE to initiate communication or synchronization with a base station using a random access procedure. The UE may use a random access procedure to initiate communication or synchronization for various purposes. The UE may use contention-based random access or contention-free random access. In at least one example embodiment, contention-based random access refers to a random access procedure in which a UE uses resources shared across multiple UEs, such that contention for the same resources may occur. In this case, a contention resolution may be part of the random access procedure. In at least one example embodiment, contention-free random access refers to a random access procedure in which a UE uses resources dedicated to that UE. In this case, a contention resolution may be avoided in the random access procedure. In at least one example embodiment, a random access resource refers to any resource that a UE may configure for performing a random access procedure, such as one or more random access preambles, time-frequency resources for performing a random access procedure, and the like.

[0066] In addition, there are two different types of random access procedures, a 4-step random access type and a 2-step random access type.

[0067] Figure 4A-4B is a diagram illustrating a random access (RA) procedure according to at least one example embodiment. Figure 4A-4B The examples are merely examples and do not necessarily limit the scope of the claims.

[0068] Figure 4A is a diagram illustrating a 4-step random access procedure between a UE 401 and a base station 402 according to at least one example embodiment.

[0069] At communication 403, UE 401 sends Message 1 to a base station. In at least one example embodiment, Message 1 is a random access request. In at least one example embodiment, Message 1 includes a random access preamble. In at least one example embodiment, Message 1 is sent on a random access channel (RACH) using random access resources.

[0070] At communication 404, the UE receives Message 2 from base station 402. In at least one example embodiment, Message 2 is a random access response. In at least one example embodiment, the random access response indicates resources for the UE to use for transmission of Message 3.

[0071] At communication 405, the UE sends message 3 to base station 402 using the resources indicated by message 2. Message 3 may be referred to as a data transmission. In at least one example embodiment, message 3 is a physical uplink shared channel (PUSCH) transmission using the PUSCH resources indicated by message 2.

[0072] At communication 406, if necessary, the UE receives message 4. In at least one example embodiment, message 4 is a contention resolution message. In this case, it may be desirable for the UE to perform a 2-step random access procedure.

[0073] In some cases, it may be desirable for the UE to perform a random access procedure with a latency reduced from that of a 4-step random access procedure.

[0074] Figure 4B is a diagram illustrating a 2-step random access procedure between a UE 401 and a base station 402 according to at least one example embodiment.

[0075] At communication 423, UE 401 sends message A to base station 402. In at least one example embodiment, message A includes a random access request and a data transmission. In at least one example embodiment, message A includes an RA preamble transmitted on the RACH and a data transmission on the PUSCH.

[0076] At communication 424, UE 401 receives message B from base station 402. In at least one example embodiment, message B includes a random access response and any necessary contention resolution messages.

[0077] Although the 2-step RA procedure can reduce latency, initiating a 4-step RA procedure may be more reliable. Therefore, depending on the situation, the 2-step RA type may be preferred over the 4-step RA type at times, and the 4-step RA type may be preferred over the 2-step RA type at other times. For example, in some cases, it may be desirable to measure the Reference Signal Received Power (RSRP) of the downlink path loss reference to determine whether to initiate a 2-step RA type. In some cases, it may be desirable to condition the performance of the 2-step RA type procedure on whether the measured RSRP of the downlink path loss reference is greater than a configured Message-A threshold. In at least one example embodiment, the UE measures the RSRP of the downlink path loss reference. In at least one example embodiment, the UE determines whether the measured Reference Signal Received Power (RSRP) of the downlink path loss reference is greater than the Message-A threshold. In at least one example embodiment, if the measured RSRP of the downlink path loss reference is greater than the Message-A threshold, the UE performs a 2-step RA. In at least one example embodiment, if the measured RSRP of the downlink path loss reference is not greater than the Message-A threshold, the UE performs a 4-step RA.

[0078] In at least one example embodiment, the UE receives configuration information for performing an RA procedure. In at least one example embodiment, the UE receives BWP configuration information, which includes configuration information for performing an RA procedure. In this manner, the configuration information for the RA procedure can be specific to a particular BWP. For example, the UE can receive BWP uplink configuration information including RA configuration information.

[0079] In at least one example embodiment, a BWP is configured with common RA resources and / or dedicated RA resources. In at least one example embodiment, the term common RA resources refers to resources that a UE can share with other UEs. For example, a UE may receive a BWP configuration that includes the configuration of RA resources in a common configuration information element, such as a RACH common configuration information element, a RACH 2-step RA common configuration information element, and / or the like. Common RA resources may also be referred to as contention-based RA (CBRA) resources. In at least one example embodiment, the term dedicated RA resources refers to resources specifically allocated to a UE. For example, a UE may receive a BWP configuration that includes the configuration of RA resources in a dedicated configuration information element, such as a RACH dedicated configuration information element (e.g., a rach-configDedicated information element). Dedicated RA resources may also be referred to as contention-free RA (CFRA) resources, dedicated contention-free RA resources, and / or the like. In at least one example embodiment, in the absence of any other qualifying terms, the term RA resources refers to dedicated RA resources and / or common RA resources.

[0080] In at least one example embodiment, 2-step RA resources are configured differently from 4-step RA resources. The term 2-step RA resources may refer to RA resources used to perform a 2-step RA type. In at least one example embodiment, due to differences in the parameters associated with each of these configurations, the information elements used to configure 2-step RA resources differ from the information elements used to configure 4-step RA resources. For example, dedicated 4-step RA resources may be included in a CFRA information element, and dedicated 2-step RA resources may be included in a 2-step SFRA information element. In another example, public 4-step RA resources may be included in a public RACH configuration information element, and public 2-step RA resources may be included in a public RACH 2-step configuration information element. In at least one example embodiment, in the absence of any other qualifying terms, the terms 4-step RA resources and RA resources for a 4-step RA type refer to dedicated 4-step RA resources and / or public 4-step RA resources. In at least one example embodiment, in the absence of any other qualifying terms, the terms 2-step RA resources and RA resources for a 2-step RA type refer to dedicated 2-step RA resources and / or public 2-step RA resources.

[0081] In at least one example embodiment, the RA resource configuration information includes parameters specifying particular resources and parameters governing the use of such resources. For example, the RA resource configuration information may include parameters specifying time-frequency resources, RA preambles, and / or the like. Additionally, the 2-step RA resource configuration information may include threshold information, such as a Message A threshold.

[0082] There are many reasons for initiating a random access procedure. For example, based on an indication from a base station, or as part of a reconfiguration, it may be desirable to perform an RA procedure for handover for a UE initiating data communication. In at least one example embodiment, reconfiguration refers to an RRC reconfiguration procedure used to establish a radio connection between the UE and the base station. In some cases, it may be desirable for the UE to perform a reconfiguration with synchronization (also referred to as a reconfiguration with synchronization). For example, reconfiguration with synchronization may be useful for handover, handling RRC reconfiguration failures, radio link failure recovery, and / or the like. In at least one example embodiment, the UE performs a RA procedure as part of the reconfiguration with synchronization. In at least one example embodiment, the RA procedure is initiated by the reconfiguration with synchronization. In such an example, the UE initiates the RA procedure in order to complete the reconfiguration procedure with synchronization.

[0083] Reconfiguration with synchronization can be initiated by the base station or by the UE. In at least one example embodiment, the UE receives an RRC reconfiguration message that includes an instruction to perform reconfiguration with synchronization. In this way, reconfiguration with synchronization is initiated by the base station, and the UE performs reconfiguration with synchronization in response to receiving the RRC message. In some cases, it may be desirable for the UE to store configuration information to be used for RRC reconfiguration in certain situations on the UE. For example, in the event of RRC reconfiguration failure, radio link failure, and / or the like, it may be desirable for the UE to use such configuration information to perform reconfiguration with synchronization. In at least one example embodiment, the UE receives conditional RRC reconfiguration information and stores the conditional RRC reconfiguration. In at least one example embodiment, in the event that a previous reconfiguration with synchronization has failed, the UE uses the stored conditional RRC reconfiguration to perform reconfiguration with synchronization. In at least one example embodiment, the conditional RRC reconfiguration includes a cell candidate configuration for reconfiguration. In at least one example embodiment, where a previous reconfiguration with synchronization failed and the UE is configured with a stored conditional RRC reconfiguration associated with a cell candidate configuration, the UE initiates a reconfiguration with synchronization using the cell candidate configuration to recover.

[0084] Low Layer Triggered Mobility (LTM) uses low layer signaling to implement reconfiguration while maintaining the configuration of the upper layers. In some cases, it is desirable that LTM reduce latency and signaling overhead during reconfiguration. During LTM, the user plane can continue whenever possible without being reset, allowing candidate cells to avoid data loss and additional delays in data recovery. Further, security updates can be avoided in LTM. In at least one example embodiment, LTM is used to perform reconfiguration with synchronization. In at least one example embodiment, a cell candidate can indicate that the cell candidate supports LTM. In at least one example embodiment, an LTM candidate refers to a cell candidate configured for LTM. In at least one example embodiment, the UE uses a Low Layer Triggered Mobility (LTM) candidate to initiate reconfiguration with synchronization for recovery. In such an example, the RA process is initiated by the reconfiguration with synchronization using the LTM candidate.

[0085] A UE can be configured with a number of RA resources for a BWP. When initiating an RA procedure, the UE must determine which RA type to perform based on the RA resources configured for the BWP and the purpose of the RA procedure. In at least one example embodiment, the UE performs a specific RA type based on the RA resources configured for the BWP and the manner in which the RA procedure was initiated.

[0086] In some cases, depending on the reason for initiation of the RA procedure, it may be desirable to prefer dedicated RA resources over common RA resources, public RA resources over dedicated RA resources, 4-step RA type over 2-step RA type, 2-step RA type over 4-step RA type, and / or the like. For example, in the case where the RA procedure is initiated by a reconfiguration with synchronization, it may be desirable to avoid the long latency associated with contention resolution of the RA procedure initiated by the reconfiguration with synchronization by preferring dedicated RA resources over public RA resources. Furthermore, in the case where the RA procedure is initiated by a reconfiguration with synchronization using dedicated RA resources, it may be desirable to prioritize reliability by preferring 4-step RA type over 2-step RA type. Conversely, in the case where the RA procedure is initiated by a reconfiguration with synchronization using common RA resources, it may be desirable to prioritize reducing overhead and latency by preferring 2-step RA type over 4-step RA type.

[0087] However, in the case of initiating a reconfiguration with synchronization for recovery using an LTM candidate configuration, it may be desirable to use a different prioritization. For example, in this case, it may be desirable to avoid using dedicated RA resources rather than prioritizing them. Therefore, determining which RA type procedure to perform must not only consider whether the RA procedure was initiated by a reconfiguration with synchronization, but also whether a reconfiguration with synchronization for recovery was initiated using an LTM candidate configuration when determining which RA type procedure to perform.

[0088] After the UE applies the appropriate priorities based on how the RA procedure was initiated, there are several ways that the UE can perform the appropriate RA type procedure.

[0089] For example, each set of RA resources may have a different RA resource set identifier that uniquely specifies the RA resource set for the BWP. In this case, it may be desirable to perform an RA type procedure by selecting an RA resource set identifier based on the RA configuration information and the manner in which the RA procedure is initiated, and then use the RA type associated with the RA resource set identifier to determine which RA type procedure to perform. This type of solution necessarily requires an RA resource set identifier. In this case, a unified RA resource set structure may also be needed that can include parameters for each different type of RA resource, such as dedicated RA resources, public RA resources, 2-step RA type resources, 4-step RA type resources, and so on. In this way, each RA resource set can generally be indexed by an RA resource set identifier, which can be used to select and specify the RA resource set for use in the RA procedure.

[0090] In another example, the UE can set the RA type of the RA procedure based on the RA configuration information and the manner in which the RA procedure was initiated, and then use the set RA type to determine which RA type procedure to perform. This type of operation may be desirable in the absence of an RA resource set identifier. For example, based on the absence of an RA resource set identifier, it may be desirable to perform the determination of the applicable RA resource set each time specific parameters are needed. This type of solution may be necessary when there is no designated RA resource set identifier, or when there are multiple different information elements that specify the available RA resource sets for the BWP.

[0091] Figure 5A is a flow chart illustrating activities associated with performing random access according to at least one example embodiment. Figure 5A The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 5A A collection of operations.

[0092] At block 501, the apparatus sets the RA type. For example, the setting of the RA type may be based on the RA configuration information for the BWP and the way of initiating the RA procedure.

[0093] At block 502, the apparatus performs an RA procedure based on the set RA type. For example, if the set RA type is a 4-step RA type, the UE performs a 4-step RA procedure. In another example, if the set RA type is a 2-step RA type, the UE performs a 2-step RA procedure.

[0094] Figure 5B is a flow chart illustrating activities associated with performing random access according to at least one example embodiment. Figure 5B The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 5B A collection of operations.

[0095] At block 521, the apparatus selects an RA resource set. For example, the selection of the RA resource set may be based on RA configuration information for the BWP and the manner in which the RA procedure is initiated.

[0096] At block 522, the apparatus performs an RA procedure based on the RA type included in the selected RA resource set. For example, if the selected RA resource set indicates that the RA resources are applied to a 2-step RA type, the UE performs a 2-step RA procedure. In another example, if the selected RA resource set indicates that the RA resources are applied to a 4-step RA type, the UE performs a 4-step RA procedure.

[0097] Figure 6 is a flow chart illustrating activities associated with a random access procedure according to at least one example embodiment. Figure 6 The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 6 A collection of operations.

[0098] At block 601 , the device initiates a RA procedure for a BWP by having a synchronized reconfiguration.

[0099] At block 602, the device determines whether a reconfiguration with synchronization for recovery has been initiated using an LTM candidate configuration. If a reconfiguration with synchronization for recovery has not been initiated using an LTM candidate configuration, the flow proceeds to block 610. If a reconfiguration with synchronization for recovery has been initiated using an LTM candidate configuration, the flow proceeds to block 603.

[0100] At block 603, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with common RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the process proceeds to block 604. If the BWP is not configured with RA resources for a 2-step RA type, the process proceeds to block 605.

[0101] At block 604, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0102] At block 605, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 609. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 606.

[0103] At block 606, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 607. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 608.

[0104] At block 607, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0105] At block 608, the apparatus performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0106] At block 609, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0107] At block 610, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 611. If the active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 612.

[0108] At block 611, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0109] At block 612, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 613. If the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 614.

[0110] At block 613, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0111] At block 614, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0112] Figure 7 is a flow chart illustrating activities associated with a random access procedure according to at least one example embodiment. Figure 7 The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 7 A collection of operations.

[0113] At block 701 , the device initiates a RA procedure for a BWP by reconfiguring with synchronization.

[0114] At block 702, the device determines whether a reconfiguration with synchronization for recovery has been initiated using an LTM candidate configuration. If a reconfiguration with synchronization for recovery has not been initiated using an LTM candidate configuration, the flow proceeds to block 710. If a reconfiguration with synchronization for recovery has been initiated using an LTM candidate configuration, the flow proceeds to block 703.

[0115] At block 703, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with public RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the process proceeds to block 704. If the BWP is not configured with RA resources for a 2-step RA type, the process proceeds to block 705.

[0116] At block 704, the apparatus performs setting the RA type to a 2-step RA type, similar to the Figure 5A described.

[0117] At block 705, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 709. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 706.

[0118] At block 706, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 707. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 708.

[0119] At block 707, the device performs a step RA type setting to a 2-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5A described.

[0120] At block 708, the device performs a step RA type setting to a 4-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5A described.

[0121] At block 709, the device performs a step RA type setting to a 2-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5Adescribed.

[0122] At block 710, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 711. If the active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 712.

[0123] At block 711, the device performs a step RA type setting to a 4-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5A described.

[0124] At block 712, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 713. If the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 714.

[0125] At block 713, the device performs a step RA type setting to a 2-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5A described.

[0126] At block 714, the device performs a step RA type setting to a 4-step RA type, similar to the step RA type setting described in relation to FIG. Figure 5A described.

[0127] At block 715, the device performs an RA procedure based on the set RA type, similar to the Figure 5A described.

[0128] In some cases, it may be desirable for the base station to instruct the UE to perform synchronization by means of a fast RA procedure. For example, it may be desirable for the UE to synchronize quickly with another cell. In this case, the RA procedure may be initiated by a PDCCH command from the base station. In at least one example embodiment, the PDCCH command refers to a PDCCH transmission that is configured to cause the UE to perform the RA procedure specified by the PDCCH transmission. In at least one example embodiment, the PDCCH command indicates the RA resources to be used for the RA procedure. In at least one example embodiment, the PDCCH command is downlink control information (DCI). In at least one example embodiment, the DCI is DCI format 1_0. In at least one example embodiment, the DCI is scrambled by a cell radio network temporary identifier (C-RNTI). In at least one example embodiment, the DCI includes a frequency domain resource allocation field. In at least one example embodiment, the scrambling of the DCI by the C-RNTI and the frequency domain allocation field with each bit set to a value of 1 indicate that the DCI is initiating the RA procedure in accordance with the PDCCH command. For example, when the UE receives DCI scrambled by the C-RNTI, in the case where the frequency domain allocation field sets each bit to a value of 1, the UE may determine that the DCI is initiating an RA procedure according to a PDCCH command.

[0129] In at least one example embodiment, the DCI includes a cell indicator field. In at least one example embodiment, the cell indicator field indicates a cell for performing the RA procedure. In at least one example embodiment, the UE selects a set of RA resources configured corresponding to the cell indicated by the cell indicator field. In at least one example embodiment, the UE selects a set of RA resources configured in an early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field. In at least one example embodiment, the early uplink synchronization configuration is an information element that specifies a set of RA resources to be used for low-latency synchronization. Due to the fact that the PDCCH command is intended for fast UE synchronization, it may be desirable to utilize a 4-step RA type procedure to avoid possible delays due to reliability issues associated with a 2-step RA type procedure. In at least one example embodiment, in response to receiving the PDCCH command, the UE performs a 4-step RA procedure.

[0130] Figure 8 is a flow chart illustrating activities associated with a random access procedure according to at least one example embodiment. Figure 8 The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 8 A collection of operations.

[0131] At block 801 , the device initiates a RA procedure for a BWP by having a synchronized reconfiguration.

[0132] At block 802, the apparatus determines whether the RA procedure is initiated by a PDCCH command. If the RA procedure is initiated by a PDCCH command, the flow proceeds to block 803. If the RA procedure is not initiated by a PDCCH command, the flow proceeds to block 804.

[0133] At block 803, the apparatus performs a 4-step RA using the RA resources indicated by the PDCCH command. In at least one example embodiment, the UE selects a set of RA resources configured in the early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field, and performs the 4-step RA using the selected RA resources.

[0134] At block 804, the apparatus determines whether the RA procedure is initiated by reconfiguration with synchronization. If the UE determines that the RA procedure is initiated by reconfiguration with synchronization, the flow proceeds to block 805. If the UE determines that the RA procedure is not initiated by reconfiguration with synchronization, the flow proceeds to block 818.

[0135] At block 805, the device determines whether a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration. If a reconfiguration with synchronization for recovery was not initiated using the LTM candidate configuration, the flow proceeds to block 813. If a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration, the flow proceeds to block 806.

[0136] At block 806, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with common RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the flow proceeds to block 807. If the BWP is not configured with RA resources for a 2-step RA type, the flow proceeds to block 808.

[0137] At block 807, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0138] At block 808, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 812. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 809.

[0139] At block 809, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 810. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 811.

[0140] At block 810, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0141] At block 811, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0142] At block 812, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0143] At block 813, the device determines whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 814. If the active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 815.

[0144] At block 814, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0145] At block 815, the device determines whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 816. If the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 817.

[0146] At block 816, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0147] At block 817, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0148] At block 818, the apparatus performs RA based on the RA type determined by other criteria. For example, the apparatus may perform RA based on a different RA type than that determined by other criteria. Figure 8 The criteria discussed are used to determine the type of RA.

[0149] As previously discussed, LTM uses low-layer signaling to implement reconfiguration while maintaining upper-layer configurations. To avoid higher-layer signaling, it may be desirable for the base station to invoke the LTM RA procedure via an LTM cell handover media access control (MAC) control element (CE). In at least one example embodiment, the LTM cell handover MAC CE is a CE that instructs the UE to perform an LTM cell handover. In at least one example embodiment, the LTM cell handover involves the UE performing an RA procedure. Due to the fact that the LTM cell handover MAC CE is intended for fast UE synchronization, it may be desirable to utilize a 4-step RA type procedure to avoid potential delays due to reliability issues associated with a 2-step RA type procedure. However, the LTM cell handover MAC CE may or may not indicate contention-free resources for the associated RA procedure. In at least one example embodiment, if the LTM cell handover MAC CE indicates contention-free random access resources, the UE performs a 4-step RA using the contention-free resources indicated by the LTM cell handover MAC CE. However, if the LTM cell handover MAC CE does not indicate contention-free random access resources, the UE determines the RA type based on RA resource configuration information external to the LTM cell handover MAC CE.

[0150] Figure 9 is a flow chart illustrating activities associated with a random access procedure according to at least one example embodiment. Figure 9 The set of operations corresponding to the activities of the device (e.g. Figure 1The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1 The processor 110) works together to enable the device to perform Figure 9 A collection of operations.

[0151] At block 901 , the device initiates a RA procedure for a BWP.

[0152] At block 902, the apparatus determines whether the RA procedure is initiated by a reconfiguration with synchronization. If the UE determines that the RA procedure is initiated by a reconfiguration with synchronization, the flow proceeds to block 903. If the UE determines that the RA procedure is not initiated by a reconfiguration with synchronization, the flow proceeds to block 916.

[0153] At block 903, the device determines whether a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration. If a reconfiguration with synchronization for recovery was not initiated using the LTM candidate configuration, the flow proceeds to block 915. If a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration, the flow proceeds to block 904.

[0154] At block 904, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with public RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the flow proceeds to block 905. If the BWP is not configured with RA resources for a 2-step RA type, the flow proceeds to block 906.

[0155] At block 905, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0156] At block 906, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 910. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 907.

[0157] At block 907, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 908. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 909.

[0158] At block 908, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0159] At block 909, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0160] At block 910, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0161] At block 911, the device determines whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 912. If the active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 913.

[0162] At block 912, the apparatus performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0163] At block 913, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 914. If the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 915.

[0164] At block 914, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0165] At block 915, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0166] At block 916, the device determines whether the RA procedure is initiated by the LTM cell handover medium access control (MAC) control element (CE). If the device determines that the RA procedure is initiated by the LTM cell handover medium access control (MAC) control element (CE), the flow proceeds to block 917. If the device determines that the RA procedure is not initiated by the LTM cell handover medium access control (MAC) control element (CE), the flow proceeds to block 926.

[0167] At block 917, the apparatus determines whether the LTM cell handover MAC CE indicates contention-free random access resources. If the LTM cell handover MAC CE indicates contention-free random access resources, the process proceeds to block 918. If the LTM cell handover MAC CE does not indicate contention-free random access resources, the process proceeds to block 919.

[0168] At block 918, the apparatus performs a 4-step RA using the contention-free resources indicated by the LTM cell handover MAC CE.

[0169] At block 919, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with common RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the flow proceeds to block 920. If the BWP is not configured with RA resources for a 2-step RA type, the flow proceeds to block 921.

[0170] At block 920, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0171] At block 921, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 925. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 922.

[0172] At block 922, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 923. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 924.

[0173] At block 923, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0174] At block 924, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0175] At block 925, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0176] At block 926, the apparatus performs RA based on the RA type determined by other criteria. For example, the apparatus may perform RA based on a different RA type than that determined by other criteria. Figure 9 The criteria discussed are used to determine the type of RA.

[0177] Figure 10 is a flow chart illustrating activities associated with a random access procedure according to at least one example embodiment. Figure 10 The set of operations corresponding to the activities of the device (e.g. Figure 1 The electronic device 100) or a portion of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 In an example embodiment, by making the memory (e.g. Figure 1 The memory 140) includes computer code to transform the device (e.g. Figure 1 The electronic device 100), the computer code is configured to communicate with the processor (eg Figure 1The processor 110) works together to enable the device to perform Figure 10 A collection of operations.

[0178] At block 1001 , the device initiates a RA procedure for a BWP by having a synchronized reconfiguration.

[0179] At block 1002, the apparatus determines whether the RA procedure is initiated by a PDCCH command. If the RA procedure is initiated by a PDCCH command, the flow proceeds to block 1003. If the RA procedure is not initiated by a PDCCH command, the flow proceeds to block 1004.

[0180] At block 1003, the apparatus performs a 4-step RA using the RA resources indicated by the PDCCH command. In at least one example embodiment, the UE selects a set of RA resources configured in the early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field, and performs the 4-step RA using the selected RA resources.

[0181] At block 1004, the apparatus determines whether the RA procedure is initiated by a reconfiguration with synchronization. If the UE determines that the RA procedure is initiated by a reconfiguration with synchronization, the flow proceeds to block 1005. If the UE determines that the RA procedure is not initiated by a reconfiguration with synchronization, the flow proceeds to block 1019.

[0182] At block 1005, the device determines whether a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration. If a reconfiguration with synchronization for recovery was not initiated using the LTM candidate configuration, the flow proceeds to block 1014. If a reconfiguration with synchronization for recovery was initiated using the LTM candidate configuration, the flow proceeds to block 1006.

[0183] At block 1006, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with public RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the flow proceeds to block 1008. If the BWP is not configured with RA resources for a 2-step RA type, the flow proceeds to block 1009.

[0184] At block 1008, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0185] At block 1009, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 1013. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 1010.

[0186] At block 1010, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 1011. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 1012.

[0187] At block 1011, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0188] At block 1012, the apparatus performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0189] At block 1013, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0190] At block 1014, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 1015. If the active BWP is not configured with dedicated contention-free RA resources for the 4-step RA type, the flow proceeds to block 1016.

[0191] At block 1015, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0192] At block 1016, the apparatus determines whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type. If the BWP is configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 1017. If the BWP is not configured with dedicated contention-free RA resources for the 2-step RA type, the flow proceeds to block 1018.

[0193] At block 1017, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0194] At block 1018, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0195] At block 1019, the device determines whether the RA procedure is initiated by the LTM cell handover medium access control (MAC) control element (CE). If the device determines that the RA procedure is initiated by the LTM cell handover medium access control (MAC) control element (CE), the flow proceeds to block 1020. If the device determines that the RA procedure is not initiated by the LTM cell handover medium access control (MAC) control element (CE), the flow proceeds to block 1029.

[0196] At block 1020, the apparatus determines whether the LTM cell handover MAC CE indicates contention-free random access resources. If the LTM cell handover MAC CE indicates contention-free random access resources, the process proceeds to block 1021. If the LTM cell handover MAC CE does not indicate contention-free random access resources, the process proceeds to block 1022.

[0197] At block 1021 , the apparatus performs a 4-step RA using contention-free resources indicated by the LTM cell handover MAC CE.

[0198] At block 1022, the apparatus determines whether the BWP is configured with RA resources for a 2-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 2-step RA type includes determining whether the BWP is configured with public RA resources for a 2-step RA type. If the BWP is configured with RA resources for a 2-step RA type, the flow proceeds to block 1023. If the BWP is not configured with RA resources for a 2-step RA type, the flow proceeds to block 1024.

[0199] At block 1023, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0200] At block 1024, the apparatus determines whether the BWP is configured with RA resources for a 4-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a 4-step RA type includes determining whether the BWP is configured with common RA resources for a 4-step RA type. If the BWP is not configured with RA resources for a 4-step RA type random access, the process proceeds to block 1028. If the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 1025.

[0201] At block 1025, the apparatus determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is above the Message A threshold. If the measured RSRP of the downlink path loss reference is above the Message A threshold, the flow proceeds to block 1026. If the measured RSRP of the downlink path loss reference is not above the Message A threshold, the flow proceeds to block 1027.

[0202] At block 1026, the apparatus performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0203] At block 1027, the device performs a 4-step RA type. The performance of the 4-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0204] At block 1028, the device performs a 2-step RA type. The performance of the 2-step RA type may be similar to that of Figure 5A-5B Performance as described.

[0205] At block 1029, the apparatus performs RA based on the RA type determined by other criteria. For example, the apparatus may perform RA based on a different RA type than that determined by other criteria. Figure 10 Discuss the standard criteria for determining RA type.

[0206] Embodiments of the present invention may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware may reside on an apparatus, a separate device, or multiple separate devices. As desired, a portion of the software, application logic, and / or hardware may reside on the apparatus, a portion of the software, application logic, and / or hardware may reside on a separate device, or a portion of the software, application logic, and / or hardware may reside on multiple separate devices. In example embodiments, the application logic, software, or instruction set is maintained on any of various conventional computer-readable media.

[0207] Although various aspects of the invention are set out in the independent claims, further aspects of the invention comprise other combinations of features from the described embodiments and / or dependent claims having features of the independent claims, and not only the combinations explicitly set out in the claims.

[0208] It is also noted herein that, although the above describes example embodiments of the present invention, these descriptions should not be viewed in a limiting sense. Rather, various changes and modifications may be made without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method performed by a UE, the method comprising: Initiate a random access (RA) procedure for the bandwidth part (BWP); confirming whether the RA procedure is initiated by reconfiguration with synchronization; In case the RA procedure is initiated by the reconfiguration with synchronization: determining whether to initiate the reconfiguration with synchronization for recovery using a low layer triggered mobility (LTM) candidate configuration; In case the reconfiguration with synchronization for recovery is initiated without using the LTM candidate configuration: determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type; In case the BWP is configured with the dedicated contention-free RA resources for the 4-step RA type, performing a 4-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 4-step RA type: determining whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type; In case the BWP is configured with the dedicated contention-free RA resource for the 2-step RA type, performing a 2-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 2-step RA type, performing a 4-step RA; as well as In case the reconfiguration with synchronization is initiated for recovery using the LTM candidate configuration: determining that the BWP is configured with RA resources for a 2-step RA type; determining whether the BWP is configured with RA resources for a 4-step RA type; If the BWP is not configured with RA resources for 4-step RA type random access, performing 2-step RA; In case the BWP is configured with RA resources for 4-step RA type: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is above a Message A threshold; performing a 2-step RA if the measured RSRP of the downlink path loss reference is above the Message A threshold; as well as If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, performing a 4-step RA; as well as In case the RA procedure is not initiated by the reconfiguration with synchronization: determining that an LTM cell handover medium access control (MAC) control element (CE) indicates contention-free random access resources; and Perform the 4-step RA.

2. The method of claim 1 , wherein the dedicated contention-free RA resources are received in a rach-configDedicated information element. 3 . The method of claim 1 , wherein determining whether the BWP is configured with RA resources for the 2-step RA type comprises determining whether the BWP is configured with common RA resources for the 2-step RA type. 4 . The method of claim 1 , wherein determining whether the BWP is configured with RA resources for the 4-step RA type comprises determining whether the BWP is configured with common RA resources for the 4-step RA type.

5. The method of claim 1 , wherein initiating the reconfiguration with synchronization for recovery using an LTM candidate configuration comprises: A situation where a previous reconfiguration with synchronization failed and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

6. The method of claim 1 , wherein performing 2-step RA comprises setting a RA type to be performed as a 2-step RA type and performing the RA procedure based on the set RA type to be performed, and wherein performing 4-step RA comprises setting the RA type to be performed as a 4-step RA type and performing the RA procedure based on the set RA type to be performed.

7. The method of claim 1 , wherein performing 2-step RA comprises selecting an RA resource set and performing the RA procedure based on the RA type specified by the selected RA resource set, and wherein performing 4-step RA comprises selecting different RA resource sets and performing the RA procedure based on the RA type specified by the selected different RA resource sets.

8. A UE, comprising: at least one processor, and at least one memory, the memory comprising machine-readable instructions that, when executed by the processor, cause the UE to: Initiate a random access (RA) procedure for the bandwidth part (BWP); confirming whether the RA procedure is initiated by reconfiguration with synchronization; In case the RA procedure is initiated by the reconfiguration with synchronization: determining whether the reconfiguration with synchronization for recovery was initiated using a low layer triggered mobility (LTM) candidate configuration; In case the reconfiguration with synchronization for recovery is initiated without using the LTM candidate configuration: determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type; In case the BWP is configured with the dedicated contention-free RA resources for the 4-step RA type, performing a 4-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 4-step RA type: determining whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type; In case the BWP is configured with the dedicated contention-free RA resource for the 2-step RA type, performing a 2-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 2-step RA type, performing a 4-step RA; as well as In case the reconfiguration with synchronization is initiated for recovery using the LTM candidate configuration: determining that the BWP is configured with RA resources for a 2-step RA type; determining whether the BWP is configured with RA resources for a 4-step RA type; If the BWP is not configured with RA resources for 4-step RA type random access, performing 2-step RA; In case the BWP is configured with RA resources for 4-step RA type: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is above a Message A threshold; performing a 2-step RA if the measured RSRP of the downlink path loss reference is above the Message A threshold; as well as If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, performing a 4-step RA; as well as In case the RA procedure is not initiated by the reconfiguration with synchronization: determining that an LTM cell handover medium access control (MAC) control element (CE) indicates contention-free random access resources; and Perform the 4-step RA.

9. The UE of claim 8, wherein the dedicated contention-free RA resources are received in a rach-configDedicated information element. 10 . The UE of claim 8 , wherein determining whether the BWP is configured with RA resources for the 2-step RA type comprises determining whether the BWP is configured with common RA resources for the 2-step RA type. 11 . The UE of claim 8 , wherein determining whether the BWP is configured with RA resources for the 4-step RA type comprises determining whether the BWP is configured with common RA resources for the 4-step RA type.

12. The UE according to claim 8, wherein the case of initiating the reconfiguration with synchronization for recovery using the LTM candidate configuration comprises: A situation where a previous reconfiguration with synchronization failed and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

13. The UE according to claim 8, wherein performing 2-step RA includes setting an RA type to be performed as a 2-step RA type and performing the RA procedure based on the set RA type to be performed, and wherein performing 4-step RA includes setting the RA type to be performed as a 4-step RA type and performing the RA procedure based on the set RA type to be performed.

14. The UE of claim 8, wherein performing 2-step RA comprises selecting an RA resource set and performing the RA procedure based on the RA type specified by the selected RA resource set, and wherein performing 4-step RA comprises selecting different RA resource sets and performing the RA procedure based on the RA type specified by the selected different RA resource sets.

15. At least one non-transitory computer-readable medium comprising instructions that, when executed by a UE, perform: Initiate a random access (RA) procedure for the bandwidth part (BWP); confirming whether the RA procedure is initiated by reconfiguration with synchronization; In case the RA procedure is initiated by the reconfiguration with synchronization: determining whether the reconfiguration with synchronization for recovery was initiated using a low layer triggered mobility (LTM) candidate configuration; In case the reconfiguration with synchronization for recovery is initiated without using the LTM candidate configuration: determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type; In case the BWP is configured with the dedicated contention-free RA resources for the 4-step RA type, performing a 4-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 4-step RA type: determining whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type; In case the BWP is configured with the dedicated contention-free RA resource for the 2-step RA type, performing a 2-step RA; In case the BWP is not configured with the dedicated contention-free RA resources for the 2-step RA type, performing a 4-step RA; as well as In case the reconfiguration with synchronization is initiated for recovery using the LTM candidate configuration: determining that the BWP is configured with RA resources for a 2-step RA type; determining whether the BWP is configured with RA resources for a 4-step RA type; If the BWP is not configured with RA resources for 4-step RA type random access, performing 2-step RA; In case the BWP is configured with RA resources for 4-step RA type: determining whether a measured reference signal received power (RSRP) of a downlink path loss reference is above a Message A threshold; performing a 2-step RA if the measured RSRP of the downlink path loss reference is above the Message A threshold; as well as If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, performing a 4-step RA; as well as In case the RA procedure is not initiated by the reconfiguration with synchronization: determining that an LTM cell handover medium access control (MAC) control element (CE) indicates contention-free random access resources; and Perform the 4-step RA.

16. The medium of claim 15, wherein the dedicated contention-free RA resources are received in a rach-configDedicated information element. 17 . The medium of claim 15 , wherein determining whether the BWP is configured with RA resources for the 2-step RA type comprises determining whether the BWP is configured with common RA resources for the 2-step RA type.

18. The medium of claim 15, wherein determining whether the BWP is configured with RA resources for the 4-step RA type comprises determining whether the BWP is configured with common RA resources for the 4-step RA type.

19. The medium of claim 15, wherein the circumstances in which the reconfiguration with synchronization for recovery is initiated using an LTM candidate configuration include: A situation where a previous reconfiguration with synchronization failed and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

20. The medium of claim 15, wherein performing 2-step RA comprises selecting an RA resource set and performing the RA procedure based on the RA type specified by the selected RA resource set, and wherein performing 4-step RA comprises selecting a different RA resource set and performing the RA procedure based on the RA type specified by the selected different RA resource set.

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