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] With the development of wireless systems, there are more and more scenarios in which it is desirable to perform a random access (RA) procedure for a user equipment (UE). However, many of the scenarios involving random access procedures have different requirements and priorities. In addition, 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, etc. For a UE, it is important to be able to select the correct type of RA procedure and the correct resources for the RA procedure based on the purpose of initiating the RA procedure. Summary of the Invention

[0003] The various aspects of the examples of the present invention are set forth 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) process with a synchronized reconfiguration to a bandwidth part (BWP) by determining whether to use a low layer triggered mobility (LTM) candidate to initiate a synchronized reconfiguration for recovery in a case where the synchronized reconfiguration is not initiated using the LTM candidate configuration, determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, performing 4-step RA in a case where the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, and in a case where the 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, performing 2-step RA in a case where the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, and performing 4-step RA in a case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type, and in a case where a synchronized reconfiguration for recovery is initiated using the LTM candidate configuration: determining whether the BWP is configured with RA resources for a 2-step RA type, and in a case where 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, performing 2-step RA in a case where the BWP is not configured with RA resources for a 4-step RA type random access, and in a case where the BWP is configured with RA resources for a 4-step RA type: determining whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than a message A threshold, performing 2-step RA in a case where the measured RSRP of the downlink path loss reference is higher than the message A threshold, and performing 4-step RA in a case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold.

[0005] In at least one example embodiment, 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 a 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 a 4-step RA type.

[0008] In at least one exemplary embodiment, the case where a reconfiguration with synchronization is initiated using an LTM candidate configuration for recovery includes the case where a previous reconfiguration with synchronization fails and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

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

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

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

[0012] In at least one exemplary embodiment, performing four-step RA includes selecting an RA resource set and performing the RA procedure based on the 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, in the case where the RA procedure is initiated by a PDCCH command, performing a 4-step RA using the RA resources indicated by the PDCCH command, and in the case where the RA procedure is not initiated by a 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 in the 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, in the 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 the case where the 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, in the 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 the case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type, performing a 4-step RA, and in the case where the reconfiguration with synchronization for recovery is initiated using an LTM candidate configuration: determining whether the BWP is configured with RA resources for a 2-step RA type, and in the case where 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 the case where the BWP is not configured with RA resources for a 4-step RA type random access, performing a 2-step RA, and in the case where the BWP is configured with RA resources for a 4-step RA type: determining whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold, in the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold, performing a 2-step RA, and in the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold, performing a 4-step RA.

[0014] In at least one example embodiment, the PDCCH command 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 by the C-RNTI and a frequency-domain allocation field with each bit set to a value of 1 indicates that the DCI is initiating a 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, when the RA procedure is initiated by a PDCCH command, performing a 4-step RA using the RA resources indicated by the PDCCH command 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 including 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 the case where the RA procedure is initiated by a reconfiguration with synchronization: determining whether the reconfiguration with synchronization is initiated using a low layer triggered mobility (LTM) candidate for recovery, and in the case where the reconfiguration with synchronization is not initiated using an LTM candidate configuration for recovery: determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, and in the 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 the case where the 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 the 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 the case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type, performing a 4-step RA, and in the case where the reconfiguration with synchronization is initiated using an LTM candidate configuration for recovery: determining whether the BWP is configured with RA resources for a 2-step RA type, and in the case where 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, and in the case where the BWP is not configured with RA resources for a 4-step RA type random access, performing a 2-step RA, and in the case where the BWP is configured with RA resources for a 4-step RA type: determining whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold, and in the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold, performing a 2-step RA, and in the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold, performing a 4-step RA, and in the 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 contention-free random access resources, and in the case where the LTM cell handover MAC CE indicates contention-free random access resources, performing a 4-step RA using the contention-free resources indicated by the LTM cell handover MAC CE, and in the case where the LTM cell handover MAC CE does not indicate contention-free random access resources: determining whether the BWP is configured with RA resources for a 2-step RA type, and in the case where 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, and in the case where the BWP is not configured with RA resources for a 4-step RA type random access, performing a 2-step RA,In the case where 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 the case where the measured RSRP of the downlink path loss reference is higher than the Message A threshold, perform 2-step RA, and in the case where the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, perform 4-step RA.

[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, in the case where the RA procedure is initiated by a PDCCH command, performing a 4-step RA using the RA resources indicated by the PDCCH command, in the case where the RA procedure is not initiated by a PDCCH command: determining whether the RA procedure is initiated by a reconfiguration with synchronization, in the case where the RA procedure is initiated by a reconfiguration with synchronization: determining whether the reconfiguration with synchronization is initiated using a low layer triggered mobility (LTM) candidate for recovery, in the 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, in the case where the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, performing a 4-step RA, in the case where the 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, in the case where the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, performing a 2-step RA, in the case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type, performing a 4-step RA, in the case where the reconfiguration with synchronization for recovery is initiated using an LTM candidate configuration: determining whether the BWP is configured with RA resources for a 2-step RA type, in the case where 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 the case where the BWP is not configured with RA resources for a 4-step RA type random access, performing a 2-step RA, in the case where the BWP is configured with RA resources for a 4-step RA type: determining whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold, in the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold, performing a 2-step RA, in the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold, performing a 4-step RA, in the 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 contention-free random access resources, in the case where the LTM cell handover MAC CE indicates contention-free random access resources, performing a 4-step RA using the contention-free resources indicated by the LTM cell handover MAC CE, in the case where the LTM cell handover MAC CE does not indicate contention-free random access resources: determining whether the BWP is configured with RA resources for a 2-step RA type,When 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. If the BWP is not configured with RA resources for the 4-step RA type, perform 2-step RA. When 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. If the measured RSRP of the downlink path loss reference is higher than the message A threshold, perform 2-step RA, and if the measured RSRP of the downlink path loss reference is not higher than the message A threshold, perform 4-step RA. Description of the Drawings

[0022] To more fully understand the embodiments of the present invention, reference is now made to the following description 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] Figures 4A - 4B is a diagram illustrating a random access procedure according to at least one example embodiment,

[0027] Figures 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 flowchart illustrating activities associated with a random access procedure according to at least one example embodiment. Detailed Description

[0029] By referring to the Figures 1 to 10 in the accompanying drawings, the embodiments of the present invention and their potential advantages can be understood.

[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 always refer to like elements. 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 according to embodiments of the present invention. Thus, the use of any such term should not be regarded as limiting the spirit and scope of the embodiments of the present invention.

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

[0032] As defined herein, a "non-transitory computer-readable medium" refers to a physical medium (e.g., a volatile or non-volatile memory device) and can be distinguished from a "transitory computer-readable medium" that refers to an electromagnetic signal.

[0033] Figure 1FIG. is a block diagram showing an apparatus (such as electronic apparatus 100) according to at least one example embodiment. However, it should be understood that the illustrated and hereinafter described electronic apparatus is merely an illustration of an electronic apparatus that can benefit from the embodiments of the present invention, and thus, should not be used to limit the scope of the present invention. Although electronic apparatus 100 is illustrated and will be described hereinafter for purposes of example, other types of electronic apparatus can readily adopt the embodiments of the present invention. Electronic apparatus 100 can be a network node (such as a user equipment (UE) or a base station), and / or can be a personal digital assistant (PDA), pager, mobile computer, desktop computer, television, gaming apparatus, laptop computer, tablet computer, media player, camera, video recorder, mobile phone, global positioning system (GPS) apparatus, automobile, telephone booth, electronic desk, and / or any other type of electronic system. In addition, the apparatus of at least one example embodiment does not have to be the entire electronic apparatus, but can be a component or group of components of the electronic apparatus in other example embodiments. For example, the apparatus can be an integrated circuit, an integrated circuit set, and / or the like.

[0034] Furthermore, the apparatus can readily adopt the embodiments of the present invention regardless of its intention to provide mobility. In this regard, even though the embodiments of the present invention can be described in connection with mobile applications, it should be understood that the embodiments of the present invention can be utilized in connection with a wide variety of other applications both in and outside the mobile communication industry. For example, the apparatus can be at least a part of a non-portable apparatus (such as a large screen television, an electronic desk, a telephone booth, an automobile, and / or the like).

[0035] In at least one example embodiment, electronic apparatus 100 includes a processor 110 and a memory 140. Processor 110 can be any type of processor, controller, embedded controller, processor core, and / or the like. In at least one example embodiment, processor 110 utilizes computer program code to cause the apparatus to perform one or more actions. 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. Non-volatile memory can include EEPROM, flash memory, and / or the like. Memory 140 can store any one of several pieces of information as well as data. Electronic apparatus 100 can use this information and data to implement one or more functions of electronic apparatus 100, such as the functions described herein. In at least one example embodiment, memory 140 includes computer program code such that the memory and the computer program code are configured to work with the processor to cause the apparatus to perform one or more actions described herein.

[0036] The electronic device 100 may further include a transceiver 120. In at least one exemplary embodiment, the transceiver 120 is coupled to one or more antennas 130. In at least one exemplary embodiment, the processor 110 provides signals to and / or receives signals from the transceiver 120. The signals may include signaling information according to communication interface standards, user voice, 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 according to second-generation (2G) wireless communication protocols such as IS-136 (Time Division Multiple Access (TDMA)), Global System for Mobile Communications (GSM), and IS-95 (Code Division Multiple Access (CDMA)), according to 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 according to 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 circuitry, for implementing audio, video, communication, navigation, logic functions, and / or the like, and for implementing embodiments of the present invention, which embodiments include, for example, one or more of the functions described herein. For example, the processor 110 may include components such as digital signal processor devices, microprocessor devices, various analog-to-digital converters, digital-to-analog converters, processing circuitry, and other support circuitry for performing various functions, which functions include, for example, one or more of the functions described herein. The apparatus may perform control and signal processing functions of the electronic device 100 among these devices according to the respective capabilities of these devices. Thus, the processor 110 may include functions 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 functions for operating one or more software programs that may be stored in a memory and that, among other things, may cause the processor 110 to implement at least a portion of an embodiment, at least a portion of which embodiment includes, 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 page content, according to: 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 output devices, which may include audio output devices (such as ringers, headphones, speakers), haptic output devices (such as vibration transducers, electronically deformable surfaces, electronically deformable structures), visual output devices (such as displays and / or lights). The electronic device may include input devices, such as light sensors, proximity sensors, microphones, touch sensors, force sensors, buttons, keyboards, motion sensors, magnetic field sensors, cameras, and / or the like. In at least one example embodiment, the apparatus receives an indication of an input. The apparatus may receive the indication from sensors, drivers, separate devices, and / or the like. Information indicating the input may include information conveying information such as: an indication of the input, an aspect of the indication of the input, an occurrence of the indication of the input, and / or the like.

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

[0040] One or more base stations 202 may communicate wirelessly with one or more UEs (e.g., UE 201 or UE 204) via one or more base station antennas. Each base station 202 may provide communication coverage for a corresponding geographic coverage area. Communication links in the wireless communication system 200 may include an uplink transmission from a UE to a base station 202, or a downlink transmission from a base station 202 to a UE. According to various techniques, control information and data may be multiplexed on an uplink channel or a downlink channel. For example, time-division multiplexing (TDM) techniques, frequency-division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques may be used to multiplex control information and data on a downlink channel. In some examples, control information transmitted during a transmission time interval (TTI) of a downlink channel may 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 can be dispersed, and each UE can be fixed or mobile. A UE can also be referred to as a mobile station, user station, mobile unit, user unit, radio unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, cellular phone, user agent, mobile client, client, or some other suitable term. A UE can also be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, personal electronic device, handheld device, personal computer, wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, machine type communication (MTC) device, electrical appliance, automobile, etc.

[0042] In some cases, a UE may also be able to communicate directly with other UEs using sidelink communication (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). For example, Figure 2 An example of such communication between UE 201 and UE 204 is provided. One or more of the UEs in a group that utilizes 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 the base station 202. In some cases, a group of UEs communicating via sidelink communication can utilize a one-to-many (1:M) system, where each UE transmits to all other UEs in the group. In some cases, the base station 202 facilitates the scheduling of resources for sidelink communication. In other cases, sidelink communication is implemented independently of the base station 202.

[0043] In some cases, UE 204 can operate as a relay UE for UE 201. For example, instead of the UE communicating directly with the base station 202, UE 204 can be configured to operate as a relay such that UE 201 communicates with the base station 202 via communication that directly passes through UE 204. For example, UE 204 can 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 can refer to data communication technologies that allow devices to communicate with each other or with a base station without human intervention. For example, M2M or MTC can refer to communication from a device integrated with sensors or meters to measure or capture information and relay that information to a central server or application, which can utilize the information or present the information to a human interacting with the program or application. Some UEs can be designed to collect information or implement automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, health 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 reduced peak rates using half-duplex (one-way) communication. MTC devices can also be configured to enter a power-saving "deep sleep" mode when not participating in active communication. 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 interface with core network 203 via a backhaul link (e.g., S1, etc.). The base stations can communicate with each other directly or indirectly (e.g., via core network 203) via other backhaul links (e.g., X2, etc.). The base station can perform radio configuration and scheduling for communicating with UEs, or can operate under the control of a base station controller (not shown). In some examples, base station 202 can be a macro cell, small cell, hot spot, and / or the like. The base station can also be referred to as an evolved NodeB (NB), such as eNB, gNB, and / or the like.

[0047] The base station 202 can be connected to the core network 203 via the 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 processes signaling between the UE 201 and the EPC. All user Internet protocol (IP) packets can be transmitted via the S-GW, which can itself 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 can provide user authentication, access authorization, tracing, IP connectivity, and other access, routing, or mobility functions. At least some of the network devices (such as the base station 202) can include subcomponents such as access network entities, which can be examples of access node controllers (ANCs). Each access network entity can communicate with several UEs via several other access network transmission entities, and each of the other access network transmission entities can be an example of a smart radio head or a transmit / receive point (TRP). In some configurations, the various functions of each access network entity or base station can be distributed across various network devices (e.g., radio heads and access network controllers), or combined into a single network device (e.g., the base station 202).

[0049] The wireless communication system 200 may operate in the ultra-high frequency (UHF) frequency band using a frequency band from 700 MHz to 2600 MHz (2.6 GHz), although some networks (e.g., wireless local area network (WLAN)) may use frequencies up to 4 GHz. This band may also be referred to as the decimeter band because the wavelengths range in length from approximately one decimeter to one meter. UHF waves may primarily propagate through 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 smaller frequencies (and longer waves) in the high frequency (HF) or very high frequency (VHF) portions of the spectrum, transmissions of UHF waves are characterized by smaller antennas and shorter ranges (e.g., less than 100 km). In some cases, the wireless communication system 200 may also utilize the extremely high frequency (EHF) portion of the spectrum (e.g., from 30 GHz to 300 GHz). This band may also be referred to as the millimeter band because the wavelengths range in length from approximately one millimeter to one centimeter. Thus, EHF antennas may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate the use of antenna arrays within the UE 201 (e.g., for directional beamforming). However, compared to UHF transmissions, EHF transmissions may experience even greater atmospheric attenuation and shorter ranges.

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

[0051] A cell can operate within the 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 the cell to be common within a BWP and different across different BWPs. For example, it may be desirable for a cell to have 2 BWPs such that time-frequency resources are configured differently between the two BWPs. Additionally, such a structure allows for a smooth transition between the configuration for a BWP and the configuration for different BWPs by simply indexing the correct BWP and referring to 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), where both the transmitter and the receiver are equipped with multiple antennas. Some parts of the wireless communication system 200 can use beamforming. For example, the base station 202 can have an antenna array that has a number of rows and columns of antenna ports, and the base station can use these antenna ports for beamforming in its communication with the UE 201. Signals can be transmitted multiple times in different directions (e.g., each transmission can be beamformed differently). A mmW receiver (e.g., a UE) can attempt multiple beams (e.g., antenna subarrays) while receiving a synchronization signal.

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

[0054] In some cases, the wireless communication system 200 may be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer layer or the PDCP layer may be IP-based. In some cases, the RLC layer may perform packet segmentation and reassembly for communication over logical channels. The Medium Access Control (MAC) layer may perform priority handling and multiplex logical channels into transport channels. The MAC layer may also use Hybrid Automatic Repeat reQuest (HARQ) to provide retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide the establishment, configuration, and maintenance of an RRC connection between the UE 201 and a network device or core network 203 that supports radio bearers for user plane data. At the Physical (PHY) layer, transport channels may be mapped to physical channels.

[0055] Time intervals in LTE or NR may be expressed as multiples of a basic time unit (which may be a sampling period of Ts = 1 / 30,720,000 seconds). Time resources may be organized according to radio frames of length 10 ms (Tf = 307200Ts), which may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include ten 1-ms subframes numbered from zero to nine. A subframe may 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-added to each symbol). Except for the cyclic prefix, each symbol contains 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit, also referred to as a TTI. In other cases, the TTI may be shorter than a subframe or may be dynamically selected (e.g., in a short TTI burst or in a selected component carrier using short TTI).

[0056] A resource element may consist of a symbol period and a 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 time 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). Thus, the more resource blocks the 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, and this feature 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 may utilize both licensed radio spectrum bands and unlicensed radio spectrum bands. For example, the wireless system 200 may adopt LTE licensed-assisted access (LTE-LAA) or LTE unlicensed (LTE U) radio access technologies or NR technologies in unlicensed bands such as the 5Ghz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio spectrum band, wireless devices such as the base station 202 and the UE 201 may adopt a listen-before-talk (LBT) procedure to ensure that the channel is unoccupied before transmitting data. In some cases, operation in the unlicensed band may be based on a CA configuration combined with CCs operating in the licensed band. Operation in the unlicensed spectrum may include downlink transmission, uplink transmission, or both. Duplexing in the unlicensed spectrum may be based on FDD, TDD, or a combination of both.

[0059] Figure 3 FIG. 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 uses physical channels to provide an information transfer service to higher layers. The PHY layer 304 may be connected to the media access control (MAC) layer 303 located at a higher layer via a transport channel. Data may be conveyed between the MAC layer 303 and the PHY layer 304 via the transport channel. Data may be conveyed between the physical layer on the transmission side and the physical layer on the receiving side via a physical channel. Physical channels use time and frequency as radio resources. In some cases, the orthogonal frequency division multiple access (OFDMA) scheme is used to modulate physical channels in the downlink, and the single carrier frequency division multiple access (SC-FDMA) scheme is used to modulate physical channels in the uplink.

[0061] In at least one exemplary embodiment, the MAC layer 303 provides services to the radio link control (RLC) layer 302 of a higher layer via a logical channel. 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 for efficient transmission of Internet protocol (IP) packets, such as IP version 4 (IPv4) packets or IP version 6 (IPv6) packets, over a radio interface with a relatively small bandwidth.

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

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

[0064] In at least one example embodiment, the MAC layer 303 is implemented by means of MAC entities that perform various MAC layer actions. In this way, an operating network node includes one or more MAC entities for performing MAC layer activities. In operation, a MAC entity receives data from a higher layer in a MAC SDU for transmission. The MAC entity performs various operations on the MAC SDU received from the higher layer for transmission, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The MAC entity performs these operations on the received MAC SDU to generate a MAC PDU, which is transmitted in a manner that the MAC entity sends the MAC SDU to a lower layer 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. A UE may use a random access procedure to initiate communication or synchronization for various purposes. A 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, the random access procedure may avoid a contention resolution. In at least one example embodiment, random access resources refer to any resources that may be configurable for a UE to perform a random access procedure, such as one or more random access preambles, time-frequency resources for performing a random access procedure, etc.

[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] Figures 4A - 4B is a diagram illustrating a random access (RA) procedure according to at least one example embodiment. Figures 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, the UE 401 sends Message 1 to the 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 the 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 Message 3 transmission.

[0071] At communication 405, the UE sends Message 3 to the base station 402 using the resources indicated by Message 2. Message 3 may be referred to as 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 two-step random access procedure.

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

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

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

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

[0077] Although the two-step RA process can reduce latency, initiating a four-step RA process may be more reliable. Thus, depending on the situation, sometimes the two-step RA type is preferred compared to the four-step RA type, and at other times the four-step RA type may be preferred compared to the two-step RA type. For example, in some cases, it may be desirable to measure the reference signal received power (RSRP) of a downlink path loss reference to determine whether to initiate the two-step RA type. In some cases, it may be desirable to condition the performance of the two-step RA type process on the measured RSRP of the downlink path loss reference being 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 above the message A threshold. In at least one example embodiment, in the case where the measured RSRP of the downlink path loss reference is above the message A threshold, the UE performs the two-step RA. In at least one example embodiment, in the case where the measured RSRP of the downlink path loss reference is not above the message A threshold, the UE performs the four-step RA.

[0078] In at least one example embodiment, the UE receives configuration information for performing the RA process. In at least one example embodiment, the UE receives BWP configuration information that includes the configuration information for performing the RA process. In this way, the configuration information for the RA process can be specific to a particular BWP. For example, the UE may receive BWP uplink configuration information that includes RA configuration information.

[0079] In at least one example embodiment, the 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 the UE can share with other UEs. For example, the 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 two-step RA common configuration element, and / or the like. The 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 that are specifically allocated to the UE. For example, the 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., the rach-configDedicated information element). The 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, the 2-step RA resources are configured differently from the 4-step RA resources. The term 2-step RA resources may refer to the RA resources for performing the 2-step RA type. In at least one example embodiment, due to the differences in the relevant parameters of each of these configurations, the information elements for configuring the 2-step RA resources are different from the information elements for configuring the 4-step RA resources. For example, dedicated 4-step RA resources may be included in the CFRA information element, and dedicated 2-step RA resources may be included in the 2-step SFRA information element. In another example, common 4-step RA resources may be included in the common RACH configuration information element, and common 2-step RA resources may be included in the common RACH 2-step configuration information element. In at least one example embodiment, in the absence of any other qualifying terms, the term 4-step RA resources and the RA resources for the 4-step RA type refer to dedicated 4-step RA resources and / or common 4-step RA resources. In at least one example embodiment, in the absence of any other qualifying terms, the term 2-step RA resources and the RA resources for the 2-step RA type refer to dedicated 2-step RA resources and / or common 2-step RA resources.

[0081] In at least one example embodiment, the RA resource configuration information includes parameters specifying a particular resource and parameters for managing the use of such a resource. For example, the RA resource configuration information may include parameters specifying time-frequency resources, RA preambles, and / or the like. In addition, 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 a UE and a 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, a 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 an RA procedure as part of a reconfiguration with synchronization. In at least one example embodiment, the RA procedure is initiated by a reconfiguration with synchronization. In such an example, the UE initiates the RA procedure in order to complete the reconfiguration with synchronization procedure.

[0083] A reconfiguration with synchronization can be initiated by the base station or can be initiated by the UE. In at least one example embodiment, the UE receives an RRC reconfiguration message that includes an indication for performing a reconfiguration with synchronization. In this way, the reconfiguration with synchronization is initiated by the base station, and the UE performs the reconfiguration with synchronization in response to receiving the RRC message. In some cases, it may be desirable for the UE to store on the UE the configuration information that is to be used for RRC reconfiguration in certain cases. For example, in cases such as when the RRC reconfiguration fails, a radio link fails, and / or the like, it may be desirable for the UE to use this configuration information to perform a 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 case where a previous reconfiguration with synchronization has failed, the UE uses the stored conditional RRC reconfiguration to perform a reconfiguration with synchronization. In at least one example embodiment, the conditional RRC reconfiguration includes a cell candidate configuration for the reconfiguration. In at least one example embodiment, in the case where a previous reconfiguration with synchronization has failed and the UE is configured with the stored conditional RRC reconfiguration associated with the cell candidate configuration, the UE uses the cell candidate configuration to initiate a reconfiguration with synchronization for recovery.

[0084] Low layer triggered mobility (LTM) uses low layer signaling to achieve reconfiguration while maintaining the configuration of the upper layer. In some cases, it is desirable for LTM to reduce the latency and signaling overhead during reconfiguration. During LTM, the user plane can continue whenever possible without the need for reset, enabling the candidate cell to avoid additional delays in data loss and data recovery. Further, security updates can be avoided in LTM. In at least one example embodiment, LTM is used to perform a 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 a reconfiguration with synchronization for recovery. In such an example, the RA procedure is initiated by the reconfiguration with synchronization using the LTM candidate.

[0085] The UE can configure a large number of RA resources for a BWP. When initiating an RA procedure, the UE must determine which type of RA 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 an RA procedure of a specific RA type based on the RA resources configured for the BWP and based on the way the RA procedure is initiated.

[0086] In some cases, depending on the reason for initiating the RA process, it may be desirable to prefer dedicated RA resources over common RA resources, common RA resources over dedicated RA resources, 4-step RA types over 2-step RA types, 2-step RA types over 4-step RA types, and / or the like. For example, in the case where the RA process is initiated by a reconfiguration with synchronization, by preferring dedicated RA resources over common RA resources, it may be desirable to avoid the long latency associated with competing solutions for RA processes initiated by a reconfiguration with synchronization. Further, in the case where the RA process is initiated by a reconfiguration with synchronization that uses dedicated RA resources, it may be desirable to prioritize reliability by preferring 4-step RA types over 2-step RA types. Conversely, in the case where the RA process is initiated by a reconfiguration with synchronization that uses common RA resources, it may be desirable to prioritize reducing overhead and latency by preferring 2-step RA types over 4-step RA types.

[0087] However, in the case where a reconfiguration with synchronization is initiated using an LTM candidate configuration for recovery, it may be desirable to use a different order of preference. For example, in such a case, it may be desirable to avoid using dedicated RA resources rather than prioritize them. Therefore, determining which RA type process to perform must consider not only whether the RA process is initiated by a reconfiguration with synchronization, but also whether a reconfiguration with synchronization has been initiated using an LTM candidate configuration for recovery when determining which RA type process to perform.

[0088] After the UE applies an appropriate order of preference based on the way the RA process is initiated, the UE has several ways to perform the appropriate RA type process.

[0089] For example, each set of RA resources can have a different RA resource set identifier that uniquely specifies the RA resource set for a BWP. In such a case, it may be desirable to perform the RA type process by selecting an RA resource set identifier based on the RA configuration information and the way the RA process is initiated, and then using the RA type associated with the RA resource set identifier to determine which RA type process to perform. This type of solution necessarily requires an RA resource set identifier. In such a 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, common 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 that can be used to select and specify the RA resource set for use in the RA process.

[0090] In another example, the UE can set the RA type of the RA procedure based on the RA configuration information and the way the RA procedure is 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 required. This type of solution may be necessary when there is no specified RA resource set identifier, or when there are multiple different information elements specifying available RA resource sets for a BWP.

[0091] Figure 5A is a flowchart illustrating activities associated with performing random access according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 5A activities. A device (such as Figure 1 the electronic device 100) or a part of the device can utilize this set of operations. The device may include components for performing such operations, including for example Figure 1 the processor 110. In an example embodiment, the device (such as Figure 1 the electronic device 100) is transformed by causing a memory (such as Figure 1 the memory 140) to include computer code that is configured to work with a processor (such as Figure 1 the processor 110) such that the device performs Figure 5A the set of operations.

[0092] At block 501, the device sets the RA type. For example, the setting of the RA type can be based on the RA configuration information for the BWP and the way the RA procedure is initiated.

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

[0094] Figure 5B is a flowchart illustrating activities associated with performing random access according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 5B activities. A device (such as Figure 1 the electronic device 100) or a part of the device can utilize this set of operations. The device may include components for performing such operations, including for example Figure 1 the processor 110. In an example embodiment, the device (such as Figure 1The memory 140) includes computer code to transform a device (e.g., Figure 1 the electronic device 100), and the computer code is configured to work with a processor (e.g., Figure 1 the processor 110) such that the device performs Figure 5B a set of operations.

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

[0096] At block 522, the device performs an RA procedure based on the RA type included in the selected set of RA resources. For example, if the selected set of RA resources indicates that the RA resources are applicable to a two-step RA type, the UE performs a two-step RA procedure. In another example, if the selected set of RA resources indicates that the RA resources are applicable to a four-step RA type, the UE performs a four-step RA procedure.

[0097] Figure 6 is a flowchart illustrating activities associated with a random access procedure according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to Figure 6 the activities. A device (e.g., Figure 1 the electronic device 100) or a part of the device may utilize the set of operations. The device may include components for performing such operations, including, for example, Figure 1 the processor 110. In an example embodiment, by causing a memory (e.g., Figure 1 the memory 140) to include computer code to transform a device (e.g., Figure 1 the electronic device 100), the computer code is configured to work with a processor (e.g., Figure 1 the processor 110) such that the device performs Figure 6 a set of operations.

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

[0099] At block 602, the device determines whether the synchronized reconfiguration was initiated with the use of an LTM candidate for recovery. If the synchronized reconfiguration was not initiated with the use of an LTM candidate configuration for recovery, the flow proceeds to block 610. If the synchronized reconfiguration was initiated with the use of an LTM candidate configuration for recovery, the flow proceeds to block 603.

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

[0101] At block 604, the device performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B what is described.

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

[0103] At block 606, the device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold. If the measured RSRP of the downlink path loss reference is higher than the message A threshold, the process proceeds to block 607. If the measured RSRP of the downlink path loss reference is not higher than the message A threshold, the process proceeds to block 608.

[0104] At block 607, the device performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B what is described.

[0105] At block 608, the device performs a four-step RA type. The performance of the four-step RA type can be similar to that described with respect to Figures 5A - 5B what is described.

[0106] At block 609, the device performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B what is described.

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

[0108] At block 611, the device performs the 4 - step RA type. The performance of the 4 - step RA type can be similar to the performance described with respect to Figures 5A - 5B that which is described.

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

[0110] At block 613, the device performs the 2 - step RA type. The performance of the 2 - step RA type can be similar to the performance described with respect to Figures 5A - 5B that which is described.

[0111] At block 614, the device performs the 4 - step RA type. The performance of the 4 - step RA type can be similar to the performance described with respect to Figures 5A - 5B that which is described.

[0112] Figure 7 FIG. is a flowchart illustrating activities associated with a random access procedure according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 7 activities of. A device (such as Figure 1 electronic device 100 of ) or a portion of the device can utilize the set of operations. The device can include components for performing such operations, including for example Figure 1 processor 110 of. In an example embodiment, the device (such as Figure 1 electronic device 100 of ) is transformed by causing a memory (such as Figure 1 memory 140 of ) to include computer code configured to work with a processor (such as Figure 1 processor 110 of ) such that the device performs the Figure 7 set of operations of.

[0113] At block 701, the device initiates an RA procedure by having a synchronized re - configuration to the BWP.

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

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

[0116] At block 704, the device performs setting the RA type to a two-step RA type, similar to that described regarding Figure 5A as described.

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

[0118] At block 706, the device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the message A threshold. In the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold, the process proceeds to block 707. In the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold, the process proceeds to block 708.

[0119] At block 707, the device performs setting the RA type to a two-step RA type, similar to that described regarding Figure 5A as described.

[0120] At block 708, the device performs setting the RA type to a four-step RA type, similar to that described regarding Figure 5A as described.

[0121] At block 709, the device performs setting the RA type to a two-step RA type, similar to that described regarding Figure 5Aas described.

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

[0123] At block 711, the apparatus performs setting the RA type to the 4 - step RA type, similar to that described regarding Figure 5A as described.

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

[0125] At block 713, the apparatus performs setting the RA type to the 2 - step RA type, similar to that described regarding Figure �A as described.

[0126] At block 714, the apparatus performs setting the RA type to the 4 - step RA type, similar to that described regarding Figure 5A as described.

[0127] At block 715, the apparatus performs the RA procedure based on the set RA type, similar to that described regarding Figure 5A as described.

[0128] In some cases, it may be desirable for the base station to indicate to the UE to perform synchronization by way of a fast RA process. For example, it may be desirable for the UE to synchronize quickly with another cell. In this case, the RA process 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 process specified by the PDCCH transmission. In at least one example embodiment, the PDCCH command indicates the RA resources to be used for the RA process. 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 that sets each bit to the value 1 indicate that the DCI is initiating an RA process according to the PDCCH command. For example, when the UE receives the DCI scrambled by the C-RNTI and in the case where each bit in the frequency domain allocation field is set to the value 1, the UE may determine that the DCI is initiating an RA process according to the 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 the cell for performing the RA process. 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 that corresponds 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 use a 4-step RA type process to avoid possible delays due to reliability issues associated with the 2-step RA type process. In at least one example embodiment, in response to receiving the PDCCH command, the UE performs a 4-step RA process.

[0130] Figure 8 is a flowchart illustrating activities associated with a random access process according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 8 activities. A device (e.g., Figure 1 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 1processor 110. In an example embodiment, by causing a memory (e.g., Figure 1 memory 140) to include computer code to transform a device (e.g., Figure 1 electronic device 100), the computer code is configured to work with a processor (e.g., Figure 1 processor 110) such that the device performs Figure 8 set of operations.

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

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

[0133] At block 803, the device 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 an early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field, and performs a 4-step RA using the selected RA resources.

[0134] At block 804, the device determines whether the RA procedure is initiated by a synchronized reconfiguration. If the UE determines that the RA procedure is initiated by a synchronized reconfiguration, the process continues to block 805. If the UE determines that the RA procedure is not initiated by a synchronized reconfiguration, the process continues to block 818.

[0135] At block 805, the device determines whether a synchronized reconfiguration was initiated using an LTM candidate for recovery. If a synchronized reconfiguration was not initiated using an LTM candidate configuration for recovery, the process continues to block 813. If a synchronized reconfiguration was initiated using an LTM candidate configuration for recovery, the process continues to block 806.

[0136] At block 806, the device 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 continues to block 807. If the BWP is not configured with RA resources for a 2-step RA type, the process continues to block 808.

[0137] At block 807, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B The described performance.

[0138] At block 808, the apparatus determines whether the BWP is configured with RA resources for a four-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for a four-step RA type includes determining whether the BWP is configured with common RA resources for a four-step RA type. If the BWP is not configured with RA resources for four-step RA type random access, the process proceeds to block 812. If the BWP is configured with RA resources for a four-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 higher than the Message A threshold. If the measured RSRP of the downlink path loss reference is higher than the Message A threshold, the process proceeds to block 810. If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, the process proceeds to block 811.

[0140] At block 810, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B The described performance.

[0141] At block 811, the apparatus performs a four-step RA type. The performance of the four-step RA type can be similar to that described with respect to Figures 5A - 5B The described performance.

[0142] At block 812, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B The described performance.

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

[0144] At block 814, the apparatus performs a four-step RA type. The performance of the four-step RA type can be similar to that described with respect to Figures 5A - 5B The described performance.

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

[0146] At block 816, the device performs the two - step RA type. The performance of the two - step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0147] At block 817, the device performs the four - step RA type. The performance of the four - step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0148] At block 818, the device performs RA based on the RA type determined by other criteria. For example, the device can determine the RA type based on criteria different from those discussed with respect to Figure 8 the criteria discussed.

[0149] As previously discussed, LTM uses lower - layer signaling to achieve reconfiguration while maintaining the upper - layer configuration. To avoid higher - layer signaling, it may be desirable for the base station to invoke the RA process of LTM by means of an LTM cell - handover media access control (MAC) control element (CE). In at least one example embodiment, the LTM cell - handover MAC CE is the CE that commands the UE to perform an LTM cell - handover. In at least one example embodiment, the LTM cell - handover involves the UE performing an RA process. Due to the fact that the LTM cell - handover MAC CE is intended for fast UE synchronization, it may be desirable to use the four - step RA type process to avoid possible delays due to the reliability issues associated with the two - step RA type process. However, the LTM cell - handover MAC CE may or may not indicate contention - free resources for the associated RA process. In at least one example embodiment, in the case where the LTM cell - handover MAC CE indicates contention - free random access resources, the UE uses the contention - free resources indicated by the LTM cell - handover MAC CE to perform the four - step RA. However, in the case where the LTM cell - handover MAC CE does not indicate contention - free random access resources, the UE determines the RA type based on the RA resource configuration information external to the LTM cell - handover MAC CE.

[0150] Figure 9 is a flowchart illustrating activities associated with a random access process according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 9 activities of. The device (e.g., Figure 1The electronic device 100) or a part of the device may utilize the set of operations. The device may include components for performing such operations, including, for example Figure 1 processor 110. In an example embodiment, by causing a memory (such as Figure 1 memory 140) to include computer code to transform the device (such as Figure 1 electronic device 100), the computer code is configured to work with a processor (such as Figure 1 processor 110) such that the device performs Figure 9 the set of operations.

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

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

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

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

[0155] At block 905, the device performs a two-step RA type. The performance of the two-step RA type may be similar to that described with respect to Figures 5A - 5B that.

[0156] At block 906, the device 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 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 device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the Message A threshold. If the measured RSRP of the downlink path loss reference is higher than the Message A threshold, the process proceeds to block 908. If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, the process proceeds to block 909.

[0158] At block 908, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that Figures 5A - 5B described.

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

[0160] At block 910, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that Figures 5A - 5B described.

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

[0162] At block 912, the device performs a 4-step RA type. The performance of the 4-step RA type can be similar to that Figures 5A - 5B described.

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

[0164] At block 914, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0165] At block 915, the apparatus performs a four-step RA type. The performance of the four-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0166] At block 916, the apparatus determines whether the RA procedure is initiated by a long-term mobility (LTM) cell handover medium access control (MAC) control element (CE). If the apparatus determines that the RA procedure is initiated by an LTM cell handover media access control (MAC) control element (CE), the process proceeds to block 917. If the apparatus determines that the RA procedure is not initiated by an LTM cell handover media access control (MAC) control element (CE), the process 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 four-step RA using the contention-free resources indicated by the LTM cell handover MAC CE.

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

[0170] At block 920, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0171] At block 921, the device 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. In the case where the BWP is not configured with RA resources for 4-step RA type random access, the process proceeds to block 925. In the case where the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 922.

[0172] At block 922, the device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the Message A threshold. In the case where the measured RSRP of the downlink path loss reference is higher than the Message A threshold, the process proceeds to block 923. In the case where the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, the process proceeds to block 924.

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

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

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

[0176] At block 926, the device performs RA based on the RA type determined by other criteria. For example, the device can determine the RA type based on criteria different from those Figure 9 discussed.

[0177] Figure 10 FIG. is a flowchart illustrating activities associated with a random access procedure according to at least one example embodiment. In at least one example embodiment, there is a set of operations corresponding to the Figure 10 activities. A device (such as Figure 1 electronic device 100) or a portion of the device can utilize the set of operations. The device can include components for performing such operations, including for example Figure 1 processor 110. In an example embodiment, the device (such as Figure 1 electronic device 100) is transformed by causing a memory (such as Figure 1 memory 140) to include computer code configured to cooperate with a processor (such as Figure 1works with the processor 110) such that the device performs Figure 10 a set of operations.

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

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

[0180] At block 1003, the device 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 an early uplink synchronization configuration, the set of RA resources corresponding to the cell indicated by the cell indicator field, and performs a 4-step RA using the selected RA resources.

[0181] At block 1004, the device determines whether the RA procedure is initiated by a synchronized reconfiguration. If the UE determines that the RA procedure is initiated by a synchronized reconfiguration, the process proceeds to block 1005. If the UE determines that the RA procedure is not initiated by a synchronized reconfiguration, the process proceeds to block 1019.

[0182] At block 1005, the device determines whether a synchronized reconfiguration has been initiated using an LTM candidate for recovery. If a synchronized reconfiguration has not been initiated using an LTM candidate configuration for recovery, the process proceeds to block 1014. If a synchronized reconfiguration has been initiated using an LTM candidate configuration for recovery, the process proceeds to block 1006.

[0183] At block 1006, the device 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 1008. If the BWP is not configured with RA resources for a 2-step RA type, the process proceeds to block 1009.

[0184] At block 1008, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that described regarding Figures 5A - 5B the performance.

[0185] At block 1009, the device 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. In the case where the BWP is not configured with RA resources for 4-step RA type random access, the process proceeds to block 1013. In the case where the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 1010.

[0186] At block 1010, the device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the Message A threshold. In the case where the measured RSRP of the downlink path loss reference is higher than the Message A threshold, the process proceeds to block 1011. In the case where the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, the process proceeds to block 1012.

[0187] At block 1011, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0188] At block 1012, the device performs a 4-step RA type. The performance of the 4-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0189] At block 1013, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0190] At block 1014, the device determines whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type. In the case where the BWP is configured with dedicated contention-free RA resources for a 4-step RA type, the process proceeds to block 1015. In the case where the active BWP is not configured with dedicated contention-free RA resources for a 4-step RA type, the process proceeds to block 1016.

[0191] At block 1015, the device performs a 4-step RA type. The performance of the 4-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0192] At block 1016, the device determines whether the BWP is configured with dedicated contention-free RA resources for a 2-step RA type. In the case where the BWP is configured with dedicated contention-free RA resources for a 2-step RA type, the process proceeds to block 1017. In the case where the BWP is not configured with dedicated contention-free RA resources for a 2-step RA type, the process proceeds to block 1018.

[0193] At block 1017, the apparatus performs a two-step RA type. The performance of the two-step RA type can be similar to that regarding Figures 5A - 5B as described.

[0194] At block 1018, the apparatus performs a four-step RA type. The performance of the four-step RA type can be similar to that regarding Figures 5A - 5B as described.

[0195] At block 1019, the apparatus determines whether the RA procedure is initiated by a long-term mobility (LTM) cell handover media access control (MAC) control element (CE). If the apparatus determines that the RA procedure is initiated by an LTM cell handover media access control (MAC) control element (CE), the process proceeds to block 1020. If the apparatus determines that the RA procedure is not initiated by an LTM cell handover media access control (MAC) control element (CE), the process 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 four-step RA using the contention-free resources indicated by the LTM cell handover MAC CE.

[0198] At block 1022, the apparatus determines whether the bandwidth part (BWP) is configured with RA resources for the two-step RA type. In at least one example embodiment, determining whether the BWP is configured with RA resources for the two-step RA type includes determining whether the BWP is configured with common RA resources for the two-step RA type. If the BWP is configured with RA resources for the two-step RA type, the process proceeds to block 1023. If the BWP is not configured with RA resources for the two-step RA type, the process proceeds to block 1024.

[0199] At block 1023, the apparatus performs the two-step RA type. The performance of the two-step RA type can be similar to that regarding Figures 5A - 5B as described.

[0200] At block 1024, the device 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. In the case where the BWP is not configured with RA resources for 4-step RA type random access, the process proceeds to block 1028. In the case where the BWP is configured with RA resources for a 4-step RA type, the process proceeds to block 1025.

[0201] At block 1025, the device determines whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than the Message A threshold. In the case where the measured RSRP of the downlink path loss reference is higher than the Message A threshold, the process proceeds to block 1026. In the case where the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, the process proceeds to block 1027.

[0202] At block 1026, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0203] At block 1027, the device performs a 4-step RA type. The performance of the 4-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0204] At block 1028, the device performs a 2-step RA type. The performance of the 2-step RA type can be similar to that described with respect to Figures 5A - 5B the performance described.

[0205] At block 1029, the device performs RA based on the RA type determined by other criteria. For example, the device can determine the RA type based on criteria different from those Figure 10 discussed.

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

[0207] Although various aspects of the invention are set forth in the independent claims, other aspects of the invention include other combinations of features from the described embodiments and / or the dependent claims having the features of the independent claims, and not merely the combinations explicitly recited in the claims.

[0208] It is also noted herein that while example embodiments of the invention have been described above, these descriptions should not be taken in a limiting sense. On the contrary, various changes and modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. A method performed by a UE, the method comprising: Initiating a random access (RA) procedure for a bandwidth part (BWP) with a synchronized reconfiguration; Determining whether to initiate the synchronized reconfiguration for recovery using a low layer triggered mobility (LTM) candidate configuration; In the case where the synchronized reconfiguration for recovery is not initiated using the LTM candidate configuration: Determining whether the BWP is configured with dedicated contention-free RA resources for a 4-step RA type; Performing 4-step RA in the case where the BWP is configured with the dedicated contention-free RA resources for the 4-step RA type; In the case where 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; Performing 2-step RA in the case where the BWP is configured with the dedicated contention-free RA resources for the 2-step RA type; Performing 4-step RA in the case where the BWP is not configured with the dedicated contention-free RA resources for the 2-step RA type; And In the case where the synchronized reconfiguration for recovery is initiated 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; performing 2-step RA in the case where the BWP is not configured with RA resources for 4-step RA type random access; In the case where the BWP is configured with RA resources for a 4-step RA type: Determining whether the measured reference signal received power (RSRP) of the downlink path loss reference is higher than a message A threshold; Performing 2-step RA in the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold; And Performing 4-step RA in the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold.

2. The method according to claim 1, wherein the dedicated contention-free RA resources are received in a rach-configDedicated information element.

3. The method according to claim 1, wherein determining whether the BWP is configured with RA resources for the 2-step RA type includes determining whether the BWP is configured with common RA resources for the 2-step RA type.

4. The method according to claim 1, wherein determining whether the BWP is configured with RA resources for the 4-step RA type includes determining whether the BWP is configured with common RA resources for the 4-step RA type.

5. The method according to claim 1, wherein the case of initiating the reconfiguration with synchronization for recovery using the LTM candidate configuration includes: The case where a previous synchronized reconfiguration fails and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

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

7. The method according to claim 1, wherein performing 2-step RA includes 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 includes selecting an RA resource set and performing the RA procedure based on the RA type specified by the selected RA resource set.

8. A UE, comprising: at least one processor, and at least one memory including machine-readable instructions that, when executed by the processor, cause the UE to perform: initiate a random access (RA) procedure for a bandwidth part (BWP) with synchronized reconfiguration; determine whether the synchronized reconfiguration has been initiated using a low layer-triggered mobility (LTM) candidate configuration for recovery; in the case where the synchronized reconfiguration has not been initiated using the LTM candidate configuration for recovery: determine whether the BWP is configured with dedicated contention-free RA resources for the 4-step RA type; perform 4-step RA in the case where the BWP is configured with the dedicated contention-free RA resources for the 4-step RA type; in the case where the BWP is not configured with the dedicated contention-free RA resources for the 4-step RA type: determine whether the BWP is configured with dedicated contention-free RA resources for the 2-step RA type; perform 2-step RA in the case where the BWP is configured with the dedicated contention-free RA resources for the 2-step RA type; perform 4-step RA in the case where the BWP is not configured with the dedicated contention-free RA resources for the 2-step RA type; and in the case where the synchronized reconfiguration has been initiated using the LTM candidate configuration for recovery: determine that 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; perform 2-step RA in the case where the BWP is not configured with RA resources for 4-step random access; in the case where 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; perform 2-step RA in the case where the measured RSRP of the downlink path loss reference is higher than the message A threshold; and perform 4-step RA in the case where the measured RSRP of the downlink path loss reference is not higher than the message A threshold.

9. The UE according to claim 8, wherein the dedicated contention-free RA resource is received in the rach-configDedicated information element.

10. The UE according to claim 8, wherein determining whether the BWP is configured with an RA resource for the type 2-step RA includes determining whether the BWP is configured with a common RA resource for the type 2-step RA.

11. The UE according to claim 8, wherein determining whether the BWP is configured with an RA resource for the type 4-step RA includes determining whether the BWP is configured with a common RA resource for the type 4-step RA.

12. The UE according to claim 8, wherein the case of initiating the reconfiguration with synchronization for recovery using the LTM candidate configuration includes: The case where a previous reconfiguration with synchronization fails 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 the type 2-step RA includes setting the type of RA to be performed to the type 2-step RA and performing the RA procedure based on the set type of RA, and wherein performing the type 4-step RA includes setting the type of RA to be performed to the type 4-step RA and performing the RA procedure based on the set type of RA.

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

15. At least one non-transitory computer-readable medium, the non-transitory computer-readable medium including instructions that, when executed by a UE, perform: Initiating a random access (RA) procedure for a bandwidth part (BWP) through a reconfiguration with synchronization; Determining whether the reconfiguration with synchronization has been initiated using a low-layer-triggered mobility (LTM) candidate configuration for recovery; In the case where the reconfiguration with synchronization has not been initiated using the LTM candidate configuration for recovery: Determining whether the BWP is configured with a dedicated contention-free RA resource for the type 4-step RA; In the case where the BWP is configured with the dedicated contention-free RA resource for the type 4-step RA, performing the type 4-step RA; In the case where the BWP is not configured with the dedicated contention-free RA resource for the type 4-step RA: Determining whether the BWP is configured with a dedicated contention-free RA resource for the type 2-step RA; In the case where the BWP is configured with the dedicated contention-free RA resource for the type 2-step RA, performing the type 2-step RA; In the case where the BWP is not configured with the dedicated contention-free RA resource for the type 2-step RA, performing the type 4-step RA; And In the case where the reconfiguration with synchronization has been initiated using the LTM candidate configuration for recovery: Determine that 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; perform 2-step RA if the BWP is not configured with RA resources for random access of the 4-step RA type. If 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. If the measured RSRP of the downlink path loss reference is higher than the Message A threshold, perform 2-step RA. And If the measured RSRP of the downlink path loss reference is not higher than the Message A threshold, perform 4-step RA.

16. The medium according to claim 15, wherein the dedicated contention-free RA resources are received in the rach-configDedicated information element.

17. The medium according to claim 15, wherein determining whether the BWP is configured with RA resources for the 2-step RA type includes determining whether the BWP is configured with public RA resources for the 2-step RA type.

18. The medium according to claim 15, wherein determining whether the BWP is configured with RA resources for the 4-step RA type includes determining whether the BWP is configured with public RA resources for the 4-step RA type.

19. The medium according to claim 15, wherein the case of initiating the reconfiguration with synchronization for recovery using the LTM candidate configuration includes: The case where a previous reconfiguration with synchronization fails and the UE is configured with a stored conditional RRC reconfiguration associated with the LTM candidate configuration.

20. The medium according to claim 15, wherein performing 2-step RA includes selecting a set of RA resources and performing the RA procedure based on the RA type specified by the selected set of RA resources, and wherein performing 4-step RA includes selecting a set of RA resources and performing the RA procedure based on the RA type specified by the selected set of RA resources.

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