Random access repetitions in user equipment mobility

Abstract

A method is provided that includes sending a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions, The method includes receiving a measurement report from the user equipment. The method includes making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report. And based on the determination, the method includes sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions. A corresponding apparatus is also provided.

Description

RANDOM ACCESS REPETITIONS IN USER EQUIPMENT MOBILITYTECHNOLOGICAL FIELD

[0001] The present disclosure relates generally to telecommunications and, in particular, to mobility in a telecommunications system.BACKGROUND

[0002] A telecommunications system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and / or other nodes by providing carriers between the various entities involved in the communications path. A telecommunications system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and / or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

[0003] In a wireless telecommunications system at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems.

[0004] A user can access the telecommunications system by means of an appropriate communication device or terminal. A communication device of a user may be referred to as user equipment (UE) or user device. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly withother users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and / or receive communications on the carrier.

[0005] The telecommunications system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and / or parameters which shall be used for the connection are also typically defined. One example of a telecommunications system is the Universal Mobile Telecommunications System (UMTS). Other examples of telecommunications systems are Long-Term Evolution (LTE), LTE Advanced and the so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3 GPP).BRIEF SUMMARY

[0006] Example implementations of the present disclosure are directed generally to telecommunications and, in particular, to mobility in a telecommunications system. More particularly, example implementations relate to physical random access channel repetitions for early timing advance acquisition in lower-layer triggered mobility (LTM) early synchronization. The present disclosure includes, without limitation, the following example implementations.

[0007] Some example implementations provide an apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: send a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a measurement report from the user equipment; make a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, send a control command to the user equipment to cause the user equipment to perform the random access procedure based onthe candidate cell configuration and the configuration of the random access preamble repetitions.

[0008] Some example implementations provide an apparatus comprising: means for sending a radio resource control reconfiguration message to an user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; means for receiving a measurement report from the user equipment; means for making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, means for sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0009] Some example implementations provide a method comprising: sending a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a measurement report from the user equipment; making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0010] Some example implementations provide a computer-readable storage medium that is non-transitory and has instructions stored therein that, in response to execution by at least one processing circuitry, causes an apparatus to at least: send a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a measurement report from the user equipment; make a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, send a control command to the user equipment to causethe user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0011] Some example implementations provide an apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0012] Some example implementations provide an apparatus comprising: means for receiving a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; means for receiving a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, means for performing the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0013] Some example implementations provide a method comprising: receiving a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, performing the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0014] Some example implementations provide a computer-readable storage medium that is non-transitory and has instructions stored therein that, in response to execution by at least one processing circuitry, causes an apparatus to at least: receive a radio resourcecontrol reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0015] These and other features, aspects, and advantages of the present disclosure will be apparent from a reading of the following detailed description together with the accompanying figures, which are briefly described below. The present disclosure includes any combination of two, three, four or more features or elements set forth in this disclosure, regardless of whether such features or elements are expressly combined or otherwise recited in a specific example implementation described herein. This disclosure is intended to be read holistically such that any separable features or elements of the disclosure, in any of its aspects and example implementations, should be viewed as combinable unless the context of the disclosure clearly dictates otherwise.

[0016] It will therefore be appreciated that this Brief Summary is provided merely for purposes of summarizing some example implementations so as to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above described example implementations are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. Other example implementations, aspects and advantages will become apparent from the following detailed description taken in conjunction with the accompanying figures which illustrate, by way of example, the principles of some described example implementations.BRIEF DESCRIPTION OF THE FIGURE(S)

[0017] Having thus described example implementations of the disclosure in general terms, reference will now be made to the accompanying figures, which are not necessarily drawn to scale, and wherein:

[0018] FIG. 1 illustrates a telecommunications system that includes one or more public land mobile networks (PLMNs) coupled to one or more external data networks, according to some example implementations of the present disclosure;

[0019] FIG. 2 illustrates a 5G deployment of a PLMN, according to some example implementations;

[0020] FIG. 3 illustrates a signaling chart for a lower-layer triggered mobility (LTM) procedure;

[0021] FIGS. 4A, 4B, 4C and 4D illustrate a signaling chart for an LTM procedure in a CU-DU split architecture, according to some example implementations;

[0022] FIGS. 5Aand 5B are flowcharts illustrating various steps in methods according to various example implementations;

[0023] FIGS. 6A, 6B, 6C, 6D and 6E are flowcharts illustrating various steps in methods according to various example implementations; and

[0024] FIG. 7 illustrates an apparatus according to some example implementations.DETAILED DESCRIPTION

[0025] Some implementations of the present disclosure will now be described more fully hereinafter with reference to the accompanying figures, in which some, but not all implementations of the disclosure are shown. Indeed, various implementations of the disclosure may be embodied in many different forms and should not be construed as limited to the implementations set forth herein; rather, these example implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like elements throughout.

[0026] Unless specified otherwise or clear from context, references to first, second or the like should not be construed to imply a particular order. A feature described as being above another feature (unless specified otherwise or clear from context) may instead bebelow, and vice versa; and similarly, features described as being to the left of another feature else may instead be to the right, and vice versa. Also, while reference may be made herein to quantitative measures, values, geometric relationships or the like, unless otherwise stated, any one or more if not all of these may be absolute or approximate to account for acceptable variations that may occur, such as those due to engineering tolerances or the like.

[0027] As used herein, unless specified otherwise or clear from context, the “or” of a set of operands is the “inclusive or” and thereby true if and only if one or more of the operands is true, as opposed to the “exclusive or” which is false when all of the operands are true. Thus, for example, “[A] or [B]” is true if [A] is true, or if [B] is true, or if both [A] and [B] are true. Further, the articles “a” and “an” mean “one or more,” unless specified otherwise or clear from context to be directed to a singular form. Furthermore, it should be understood that unless otherwise specified, the terms “data,” “content,” “digital content,” “information,” and similar terms may be at times used interchangeably. The term “network” may refer to a group of interconnected computers including clients and servers; and within a network, these computers may be interconnected directly or indirectly by various means including via one or more switches, routers, gateways, access points or the like.

[0028] Reference may be made herein to terms specific to a particular system, architecture or the like, but it should be understood that example implementations of the present disclosure may be equally applicable to any of a number of systems, architectures and the like. For example, reference may be made to 3 GPP technologies such as Global System for Mobile Communications (GSM), UMTS, LTE, LTE Advanced, 5GNR, 5G Advanced and 6G; however, it should be understood that example implementations of the present disclosure may be equally applicable to non-3GPP technologies such as IEEE 802, Bluetooth and Bluetooth Low Energy.

[0029] Further, as used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s)with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); or (c) hardware circuit(s) and / or processor(s), such as a microprocessor s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0030] The above definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0031] FIG. 1 illustrates a telecommunications system 100 according to various example implementations of the present disclosure. The telecommunications system generally includes one or more telecommunications networks. As shown, for example, the system includes one or more public land mobile networks (PLMNs) 102 coupled to one or more other external data networks 104 - notably including a wide area network (WAN) such as the Internet. Each of the PLMNs includes a core network(CN) 106 backbone such as the Evolved Packet Core (EPC) of LTE, the 5G core network (5GC) or the like; and each of the core networks and the Internet are coupled to one or more radio access networks (RANs) 108, air interfaces or the like that implement one or more radio access technologies (RATs). As used herein, a “network device” refers to any suitable device at a network side of a telecommunications network. Examples of suitable network devices are described in greater detail below.

[0032] In addition, the system includes one or more radio units that may be varyingly known as user equipment (UE) 110, terminal device, terminal equipment, mobile station or the like. The UE is generally a device configured to communicate with a network device or a further UE in a telecommunication network. The UE may be a portable computer (e.g., laptop, notebook, tablet computer), mobile phone (e.g., cell phone, smartphone), wearable computer (e.g., smartwatch), or the like. In other examples, theUE may be an Internet of things (loT) device, an industrial loT (IIoT device), a vehicle equipped with a vehicle-to-everything (V2X) communication technology, or the like. In operation, these UEs may be configured to connect to one or more of theRANs 108 according to their particular radio access technologies to thereby access a particular CN 106 of a PLMN 102, or to access one or more of the external data networks 104 (e.g., the Internet). The external data network may be configured to provide Internet access, operator services, 3rd party services, etc. For example, the International Telecommunication Union (ITU) has classified 5G mobile network services into three categories: enhanced mobile broadband (eMBB), ultra- reliable and low-latency communications (URLLC), and massive machine type communications (mMTC) or massive internet of things (MIoT).

[0033] Examples of radio access technologies include 3 GPP radio access technologies such as GSM, UMTS, LTE, LTE Advanced, 5GNR, 5G Advanced, and 6G. Other examples of radio access technologies include IEEE 802 technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.15 (including 802.15.1 (WPAN / Bluetooth), 802.15.4 (Zigbee) and 802.15.6 (WBAN)), Bluetooth, Bluetooth Low Energy (BLE), ultra wideband (UWB), and the like. Generally, a radio access technology may refer to any 2G, 3G, 4G, 5G, 6G or higher generation mobile communication technology and their different versions, as well as to any other wireless radio access technology that may be arranged to interwork with such a mobile communication technology to provide access to the CN 106 of a mobile network operator (MNO).

[0034] In various examples, a RAN 108 may be configured as one or more macrocells, microcells, picocells, femtocells or the like. The RAN may generally include one or more radio access nodes that are configured to interact with UEs 110. In various examples, a radio access node may be referred to as a base station (BS), access point (AP), base transceiver station (BTS), Node B (NB), evolved NB (eNB), macro BS, NB (MNB) or eNB (MeNB), home BS, NB (HNB) or eNB (HeNB), next generation NB (gNB), enhanced gNB (en-gNB), next generation eNB (ng-eNB), or the like. The RAN may include some type of network controlling / governing entity responsible for control of the radio access nodes. The network controlling / governing entity and radio access node may be separate or integrated into a single apparatus. The network controlling / governingentity may include processing circuity configured to carry out various management functions, etc. The processing circuity may be associated with a memory, computer- readable storage medium or database for maintaining information required in the management functions.

[0035] A RAN 108 may be centralized or distributed. In various examples, components of a RAN may be interconnected by Ethernet, Gigabit Ethernet, Asynchronous Transfer Mode (ATM), optical fiber, dark fiber, passive wavelength division multiplexing (WDM), WDM passive optical network (WDM-PON), optical transport network (OTN), time sensitive networking (TSN) and / or any other data link layer network, possibly including radio links. The RAN may be connected to a CN 106 through one or more gateways, network functions or the like.

[0036] As will be appreciated, a PLMN 102 may be deployed in a number of different manners. In a 4GLTE deployment, the EPC is the CN 106, and the evolved UMTS terrestrial radio access network (E-UTRAN) is the RAN 108; and the E-UTRAN includes one or more eNBs (radio access nodes) configured to connect UEs 110 to the E- UTRAN to thereby access the EPC. As shown in FIG. 2, in a 5G deployment 200, the 5GC 202 is the CN, and the next generation (NG) radio access network (NG-RAN) 204 is the RAN; and the NG-RAN includes one or more gNBs 206 (radio access nodes) configured to connect UEs 208 to the NG-RAN to thereby access the 5GC. The term ‘gNB’ in 5G may correspond to the eNB in 4G LTE.

[0037] Some deployments of 4G LTE and 5G in particular are considered standalone (SA) deployments. Other deployments combine 4G LTE and 5G technologies, and are referred to as non-standalone (NSA) deployments. In some deployments, the E-UTRAN includes one or more ng-eNBs that are configured to communicate with the 5GC, and that may also be configured to communicate with one or more gNBs. Similarly, in another deployment, the NG-RAN may include one or more en-gNBs that are configured to communicate with the EPC, and that may also be configured to communicate with one or more eNBs. In various instances, a single UE 110, 208 a dual-mode or multimode UE, may support multiple (two or more) RANs — thereby being configured to connect to multiple RANs, such as 4G LTE and 5G.

[0038] In various instances, a single UE 110, 208 a dual-mode or multimode UE, may support multiple (two or more) RANs — thereby being configured to connect to multiple RANs. For example, a particular UE may support both LTE and 5G NR radio access technologies. In this regard, a number of deployments support dual connectivity (DC), and in some particular examples multi-radio dual connectivity (MR-DC), in which a UE may be configured to connect to two different radio access nodes connected via a nonideal backhaul, one of the radio access nodes providing NR access and the other radio access node providing either E-UTRA or NR access. In these deployments, one radio access node may act as a master node (MN) and the other may act as a secondary node (SN).

[0039] In deployments such as the 5G deployment 200, node operations may be carried out, at least partly, in a central / centralized unit (CU) 210, such as a server, host or node, operationally coupled to a distributed unit (DU) 212, such as a radio head / node. It is also possible that node operations may be distributed among a plurality of servers, hosts or nodes. It should also be understood that the distribution of work between the 5GC 202 operations and gNB 204 operations may vary depending on implementation. Thus, a 5G network architecture may be based on a so-called CU-DU split. One gNB-CU (central node) may control one or more gNB-DUs. The gNB-CU may control a plurality of spatially separated gNB-DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some example implementations, however, the gNB-DUs (also called DU) may include, for example, the radio link control (RLC), medium access control (MAC) and physical (PHY) layers, whereas the gNB-CU (also called a CU) may include the layers above RLC, such as packet data convergence protocol (PDCP), radio resource control (RRC), and an internet protocol (IP) layer. Other functional splits are also possible. It is considered that a skilled person is familiar with the open systems interconnection (OSI) model and the functionalities within each layer.

[0040] In some example implementations, the server or CU 210 may generate a virtual network through which the server communicates with the radio node. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Such virtual network may provide flexible distribution of operationsbetween the server and the radio head / node. In practice, any digital signal processing task may be performed in either the CU or the DU 212, and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation.

[0041] Currently in 3 GPP, mainstream mobility has been conducted using higher layer (layer 3, L3 or RRC controlled) mobility. In this regard, L3 handover based mobility is a well-known and proven method for ensuring a robust way of handing over the UE 208 from one serving cell (source cell) of a radio access node (e.g., gNB 206) to a new serving cell (target cell) of the same or another radio access node. The method has been used at least since GSM and is still in use in 5G NR. It is expected that L3 mobility (legacy handover) will also be commonly used in the future.

[0042] As the wireless generations evolve, however, so does the need for new and different solutions enabling more flexible, more efficient and sometimes faster procedures making the system seem more agile. One such enhancement includes moving the execution of the ‘handover’ from one cell to another from higher layers (L3), such as RRC, to lower layers. These lower layers may be either PHY (or layer 1, LI) or MAC (or layer 2, L2). This feature is currently referred to as L1 / L2- triggered mobility, or lower- layer triggered mobility (LTM), which may reduce latency, overhead and interruption time when compared to L3 handover based mobility. In a CU-DU split architecture, LTM may support one or more of intra-DU mobility, intra-CU inter-DU mobility, or inter-CU inter-DU mobility.

[0043] FIG. 3 illustrates a signaling chart 300 for an LTM procedure of a UE 208 in a RRC connected state with a gNB 206, which has been proposed. During LTM preparation, as shown at step 301, the UE sends a L3 measurement report to the gNB, which decides to use LTM and initiate LTM candidate preparation. The gNB at step 302 transmits a RRC reconfiguration message to the UE, including the RRC configuration of one or more candidate target cells. The RRC configuration of a candidate target cell may be provided by an LTM candidate configuration information element (IE) (flin- CandidateConfig) within an LTM candidate IE (LTM-Candidate). The RRC reconfiguration message may also include a configuration of LI measurement reportingfor LTM execution. The UE stores the configurations, and the UE at step 303 transmits a RRC reconfiguration complete message to the gNB.

[0044] An early synchronization of the UE 208 with the candidate target cell(s) follows LTM preparation. As shown at steps 304A, 304B the UE 208 performs early downlink (DL) / uplink (UL) synchronization with the candidate target cell(s). During early UL synchronization, the UE may perform early timing advance (TA) acquisition with the candidate target cell(s) as requested by the gNB 206 before receiving a cell switch command. This early synchronization may reduce interruption during LTM execution, as compared to L3 handover based mobility. In this regard, the TA may be used to control the timing of uplink transmissions of a UE toward the candidate target cell(s). The UE may likewise have an acquired TA of the cell of the gNB to control the timing of uplink transmissions toward the gNB.

[0045] During early UL synchronization at step 304B, the gNB 206 may request that the UE perform early TA acquisition via contention free random access (CFRA) triggered by a physical downlink control channel (PDCCH) order (using downlink control information (DCI) format 1 0), following which the UE 208 sends a random access (RA) preamble on the physical random access channel (PRACH) towards an indicated candidate target cell. In 3GPP, the RA preamble is sent as a first message (msgl) as part of a RA procedure; and accordingly, the RA preamble may at times be referred to as msgl. In order to minimize the data interruption of the gNB due to CFRA towards the candidate target cell(s), the UE may not receive a random access response (RAR) from the network for the purpose of TA value acquisition, and the TA value of the candidate target cell may be indicated in a subsequent cell switch command.

[0046] During LTM execution, the UE 208 performs LI measurements on the configured candidate target cell(s), and the UE at step 305 transmits LI measurement reports to the gNB 206. In some examples, the LI measurements include LI reference signal received power (RSRP) measurements. In some of these examples, the LI measurement reports may be referred to as LI RSRP measurement reports.

[0047] The gNB 206 decides to execute a cell switch, and selects one of the candidate target cell(s) as a target cell for the cell switch. The gNB then at step 306 transmits a cell switch command (e.g., MAC-CE), to trigger cell switch. The UE 208 switches to theconfiguration of the target cell; and if the TA of the target cell (from step 304B) is no longer available, the UE at step 307 initiates a random access channel (RACH) procedure with the target cell to acquire the TA of the target cell. The UE then at step 308 indicates successful completion of the cell switch.

[0048] As described above, at step 304B, the UE 208 may perform a RA preamble transmission towards a candidate target cell after receiving a PDCCH order. For this RA preamble transmission, the UE may use a configuration for early UL synchronization over a UL or supplementary UL (SUL) carrier, which may be provided in one or more IES Itm-EarlyUL-SyncConfig, Itm-EarlyUL-SyncConfigSUL) within the LTM-candidate IE. Notably, the configuration for early UL synchronization (Itm-EarlyUL-SyncConfig) with the candidate target cell is provided separately from the RRC configuration (Itm- CandidateConfig) for the candidate target cell (both in the LTM-Candidate IE). The UE therefore need not process the entire RRC configuration for the candidate target cell in order to perform early TA acquisition using the configuration for early UL synchronization.

[0049] In 5G Advanced Release 18 (Rel-18), msgl repetitions with the same beam is supported on both normal uplink (NUL) and SUL for 4-step RAtype. For contention based random access (CBRA), the gNB 206 broadcasts separate RSRP thresholds for different numbers of repetitions. The UE 208 performs msgl repetition via random access channel (RACH) resources that are different from RACH resources without msgl repetition. In CFRA, msgl repetition is supported for synchronous reconfiguration (ReconfigurationWithSync), and the gNB signals the msgl repetition number explicitly. Fallback from a lower number to a higher number of msgl repetitions is also supported among the set(s) of RACH resources associated with same feature(s). Likewise, fallback from CFRA with msgl repetition to 4-step CBRA with msgl repetition using the same msgl repetition number as the one used for CFRA is also supported.

[0050] In Rel-18, msgl repetitions may be configured in the RRC layer using a number of parameters, such as the FeatureCombinationPreambles IE that associates a set of preambles with a feature combination. These parameters may be configured within ReconfigurationWithSync within the RRC reconfiguration.

[0051] It has been proposed to indicate the number of msgl repetitions in the LTM cell switch command MAC-CE. This proposal addresses the number of msgl repetitions for the RA procedure that the UE performs after receiving the cell switch command, but the proposal does not address the number of msgl repetitions for early TA acquisition (before cell switch). A proposal has also been made to indicate the number of msgl repetitions for early TA acquisition in the PDCCH order. But providing an absolute number of repetitions in the PDCCH order (DCI format 1 0) may be too costly in terms of the number of number of DCI bits needed.

[0052] In a CU-DU split architecture, early TA acquisition may be triggered by the source cell / DU 212 for a candidate target cell based on measurements reported by the UE 208. As early TA acquisition is typically triggered before cell switch, the threshold on the RSRP of the candidate target cell for triggering early TA acquisition is also typically lower than that for triggering cell switch. Consequently, the UE-candidate target cell link quality is typically lower at the time of early TA acquisition. To increase success rate of TA acquisition and / or improve TA estimation performance, then, the early TA acquisition process can benefit from msgl (i.e., RA preamble) repetitions.

[0053] As discussed above, the Itm-EarlyUL-SyncConfig and Itm-EarlyUL- SyncConfigSUL IE within the LTM-candidate IE include the configuration used to perform the early UL synchronization procedure over a UL or SUL carrier, but this IE (also including the RACH-ConfigGeneric IE) does not provide any configuration regarding the number of msgl repetitions.

[0054] The configuration of msgl repetitions is provided in the RRC configuration of the candidate target cell, namely, the LTM candidate configuration IE (Itm- CandidateConfig . The UE 208 typically does not access (e.g., decode) this IE until the UE receives a cell switch command indicating the candidate target cell as the target cell for cell switch, to avoid the unnecessary computational overhead for processing a configuration that may not be used.

[0055] Furthermore, a configuration of the number of msgl repetitions in the RRC reconfiguration message can only be based on the L3 measurements that triggered the handover preparation decision (steps 301-302 in FIG. 3). But until a decision for early TA acquisition is made, the link quality between the candidate target cell and the UE 208may have changed. LI measurements that are provided by the UE after handover preparation would allow the source cell / DU 212 to make a more informed decision about the number of repetitions.

[0056] In view of the foregoing, example implementations of the present disclosure provide a solution to enable msgl repetitions for early TA acquisition with minimal signaling overhead. Some example implementations provide a configuration of RA preamble (also referred to as msgl or PRACH) repetitions, and indication in case of mobility with early TA acquisition. As described in greater detail below, some example implementations provide various configurations and indications, and for UE adaptation of repetitions in case of failed random access with early TA acquisition.

[0057] According to some example implementations, an indication of a msgl repetition number / factor may be provided in the configuration for early UL synchronization. In this case, the preamble index may be provided to the UE, and the msgl repetition number / factor may be sufficient for the UE to perform msgl repetitions.

[0058] In some examples, the PDCCH order may include a flag or other indicator of activation or de-activation of msgl repetitions. In some of these examples, a msgl repetition number may be configured in the configuration for early UL synchronization, and then the gNB 206 may provide (de)activation of the msgl repetitions via a flag in the PDCCH order. In other examples, a msgl repetition number may be preconfigured at the UE (via standard specifications), and then the gNB may provide (de)activation of the msgl repetitions via a flag in the PDCCH order.

[0059] In some examples, the PDCCH order may include a field or other indicator to increase or decrease the configured number of PRACH repetitions. In some of these examples, the DCI of the PDCCH order may include a one-bit field that indicates to the UE 208 whether to increase or decrease to the next / previous supported repetition factor among a set of configured supported values (e.g., 1, 2, 4, 8). In other examples, the DCI of the PDCCH order may include a one-bit field that indicates to the UE whether to increase to the next supported repetition factor or to continue with the same number of repetitions.

[0060] In some examples, UE repetition adaptation may be provided based on failed attempt(s) of preamble transmissions. In this case, the UE 208 may increase the number of msgl repetitions after a configured number of failed RACH attempts.

[0061] Some example implementations of the present disclosure therefore provide a gNB 206 or other radio access node.

[0062] Some example implementations of the present disclosure therefore provide a gNB 206 or other radio access node that may configure a UE 208 for RA preamble repetitions. In some examples, the gNB (e.g., gNB-CU 210) may receive a configuration of RA preamble repetitions from at least one candidate target cell. The gNB may generate an LTM candidate cell configuration associated with the candidate target cell(s), and prepare a RRC reconfiguration message including the LTM candidate cell configuration and the configuration of the RA preamble repetitions.

[0063] The gNB 206 (e.g., gNB-DU 212) may send the RRC reconfiguration message to a UE 208 (at which the RRC reconfiguration message is received). The gNB may receive a measurement report (e.g., LI measurement report) from the UE, and make a determination to trigger a RA procedure of the UE towards the candidate target cell(s) based on the measurement report. Based on the determination, then, the gNB may send a control command to the UE to cause the UE to perform the RA procedure based on the LTM candidate cell configuration and the configuration of the RA preamble repetitions. In some examples, the determination is made to trigger the RA procedure for an early uplink synchronization with the candidate target cell(s), and the control command is a PDCCH order for early uplink TA acquisition. In other examples, the determination is made to trigger the RA procedure for a RA-based LTM cell switch to the candidate target cell(s), and the control command is a cell switch command

[0064] The UE 208 may receive the control command; and based on the control command, the UE may perform the RA procedure based on the LTM candidate cell configuration and the configuration of the RA preamble repetitions. In the RA procedure, the UE may send at least one RA preamble. In some examples, the control command includes an indication to activate or deactivate the RA preamble repetitions for the RA procedure. In some of these examples, the UE may send the at least one RA preamble with the RA preamble repetitions activated or deactivated based on the indication.

[0065] In some examples, the configuration of the RA preamble repetitions indicates a number of repetitions, and the control command includes an indication to increase or decrease the number of repetitions for the RA procedure. In some of these examples, the UE 208 may send the at least one RA preamble with an increase or decrease in the number of repetitions based on the indication.

[0066] In some examples, the configuration of the RA preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, and the control command (e.g., PDCCH order) indicates retransmission of at least one RA preamble. In some of these examples, the UE may determine that the maximum number of retransmissions for the number of repetitions for the at least one RA preamble has been reached. The UE may then increase the number of repetitions to an increased number of repetitions, and send the at least one RA preamble in a retransmission with the increased number of repetitions.

[0067] In some examples, the configuration of the RA preamble repetitions indicates LI measurement thresholds associated with respective numbers of repetitions. In some of these examples, the UE 208 may perform one or more LI measurements, and determine a number of repetitions based on the LI measurement thresholds and the one or more LI measurements. The UE may then send the at least one RA preamble in a retransmission with the number of repetitions as determined.

[0068] To further illustrate example implementations of the present disclosure, FIGS. 4A, 4B, 4C and 4D illustrate a signaling chart 400 for an LTM procedure in a CU-DU split architecture, according to some example implementations. As shown, the CU-DU split architecture including a CU 210, a source DU (S-DU) 212Afor a serving cell, and a target DU (T-DU) 212B for a target cell. In some examples, the UE 208 may indicate its capability of supporting msgl (RA preamble) repetitions for early TA acquisition and / or RA-based LTM cell switch. During preparation for LTM, as shown at steps 401 and 402, the UE 208 sends a L3 measurement report to the CU via the S-DU, and the CU at step 403 decides prepare one or more candidate target cells (DUs) for LTM.

[0069] As shown at steps 404, 405, 406 and 407, the CU proceeds with the UE context setup / modification procedures. The T-DU 212B may at step 405 provide a configuration of msgl repetitions (e.g., as a part of a configuration for early ULsynchronization) to the CU 210. In one example, the CU may indicate a need for the configuration of msgl repetitions to the T-DU at step 404, such as based on UE capability. And in some examples, at step 406, the configuration of msgl repetitions (e.g., as a part of the configuration for early UL synchronization) for the T-DU may be provided to the S-DU 212A.

[0070] At step 408, the CU generates RRC configuration(s) for the configured candidate target cell(s). The CU also configures the UE 208 with LI measurement reporting for LTM execution. The CU provides the S-DU 212A with TA acquisition triggering criteria and configuration(s), as well as cell switch triggering criteria and configuration(s). The triggering criteria for TA acquisition and cell switch may be similar to measurement event report triggering conditions, e.g., A3, A4 or A5 event conditions or validity of acquired TA. The triggering conditions may include, for example, a filter configuration (for LI measurements), trigger offsets, cell individual offsets, or the like.

[0071] Also at step 408, the CU 210 includes the configuration of msgl repetitions for one or more RA preambles separately from the RRC configuration(s) for the configured candidate target cell(s), such as in the configuration of early UL synchronization (Itm-EarlyUL-SyncConfig) .

[0072] In some examples, the configuration of msgl repetitions may include one or more numbers of repetitions. In some of these examples, among the number(s) of repetitions, the CU may configure a default number of repetitions to be used if no further indication is received. Additionally or alternatively, in some of these examples, one or more featureCombinationPreambles IES may include the configuration of msgl repetitions for one or more RA preambles, where sets of RA preambles configured in different featureCombinationPreambles IEs may overlap. Even further, in some examples, the configuration of msgl repetitions may indicate a maximum number of retransmissions for a given number of msgl repetitions is provided.

[0073] In some examples, the configuration of msgl repetitions may include LI RSRP measurement thresholds for each configured number of repetitions. In some of these examples, the LI RSRP measurement thresholds may be used by the UE 208 to determine an appropriate number of repetitions based on its latest LI RSRP measurements.

[0074] The CU 210 at steps 409 and 410 provides the configurations to the UE 208 via the S-DU 212A. And at steps 411 and 412, the UE sends a RRC reconfiguration complete to the CU via the S-DU.

[0075] As shown in FIG. 4B, during early synchronization, the UE 208 at step 413 performs early DL synchronization with the candidate target cell(s). The UE 208 performs LI measurements on the configured candidate target cell(s), and the UE at step 414 transmits a LI measurement report to the S-DU 212A. Based on the LI measurement report, the S-DU at step 415 decides to trigger early TA acquisition.

[0076] In steps 416-428, the S-DU 212A issues a PDCCH order for early TA acquisition to the UE 208, and the UE performs msgl transmission to the T-DU 212B. In a first option (Option 1), at steps 416 and 417, the S-DU 212A includes a msgl repetitions (de)activation flag in the PDCCH order. Based on this flag, the UE (de)activates repetition of msgl transmissions to the T-DU. If repetitions are activated, the UE uses the value configured in the configuration of early UL synchronization received in step 410.

[0077] The UE 208 at step 417 transmits msgl (RA preamble) with (de)activated repetitions to the candidate target cell(s) (T-DU 212B / cell) to signal the candidate target cell(s) to estimate the TA between the UE and the candidate target cell(s). Although not separately shown, the S-DU 212A / cell may receive a RAR from respective ones of the candidate target cell(s) indirectly via the CU 210. Alternatively, the UE may receive the RAR of respective ones of the candidate target cell(s), indirectly via the CU and the S- DU.

[0078] In a second option (Option 2), at steps 418 and 419, the S-DU 212A uses a flag in the PDCCH order to indicate to the UE 208 to increase or decrease the configured number of PRACH repetitions via a field in the PDCCH order. In some examples, the flag being set indicates to the UE to increase the number of repetitions, and the flag not being set indicates to the UE to continue using the same number of repetitions. In other examples, the flag being set indicates to the UE to decrease the number of repetitions, and the flag not being set indicates to the UE to continue using the same number of repetitions. In these examples, in case the PDCCH order is the first PDCCH order issuedto the UE, the UE may use the (default) value configured in the configuration of early UL synchronization as the reference value.

[0079] In other examples, a two-bit flag may be used to indicate to the UE 208 to use the same number of repetitions (e.g., bit field value = 00), increase the number of repetitions (e.g., bit field value = 01), or decrease the number of repetitions (e.g., bit file value = 10).

[0080] In yet other examples, the repetitions flag may be used together with a retransmission flag in the PDCCH order that indicates retransmission of RA preamble(s), which may be set in case of failed random access with early TA acquisition. The repetitions flag and retransmission flag, then, may jointly indicate a number of repetitions and whether this is an order for retransmission. In some of these examples, the flags and their meaning may be interpreted by the UE as follows:

[0081] The power ramping behavior of the UE 208 may follow a legacy approach when the number of repetitions stays the same. When the number of repetitions changes, the UE may adapt is behavior accordingly. In some examples, the UE may reset a power ramping counter when the number of repetitions changes. In other examples, the UE does not reset the power ramping counter when the number of repetitions changes.

[0082] As shown in FIG. 4C, in a third option (Option 3), at steps 420, 421, 422 and 423, the S-DU 212A issues a PDCCH order for early TA acquisition with the retransmission flag set. The UE 208 determines that the maximum number of retransmissions for this number of msgl repetitions has been reached, as configured insteps 408-410, and the UE increases the number of msgl repetitions (e.g., to the next configured value).

[0083] In a fourth option (Option 4), at steps 424, 425 and 426, the S-DU 212A issues a PDCCH order for early TA acquisition. The UE 208 determines the number of repetitions based on the LI RSRP thresholds corresponding to each configured number of repetitions and its latest LI RSRP measurements for the candidate target cell. The thresholds and the measurements may be used to determine the number of msgl repetitions, such as in a manner similar to that currently defined for CBRA. In some of these examples, numbers of repetitions may be provided by value_N, ... , value_l, which may be in decreasing order. If LI RSRP measurement(s) < LI RSRP threshold for number of repetitions value N, the number of repetitions = value N. If LI RSRP measurement(s) < LI RSRP threshold for number of repetitions value (N-l), the number of repetitions = value_(N-l). The same may apply for other repetition number values to the lowest, where if LI RSRP measurement(s) < LI RSRP threshold for number of repetitions value l , the number of repetitions = value l .

[0084] As shown in FIG. 4D, during execution, the candidate target cell at step 427 estimates the TA and provides the TA to the S-DU 212A (via the CU 210) or the UE 208 (directly or via the CU and the S-DU). Then, at step 428 onwards, the UE 208 performs LI measurements on the configured candidate target cell(s), and transmits LI measurement reports to the S-DU 212A. The S-DU at steps 429 and 430 decides to initiate a cell change to the T-DU 212B / cell, and transmits a cell switch command (e.g., MAC-GE) to trigger the cell switch / change. In examples in which the RAR is earlier received at the S-DU (instead of the UE), the S-DU provides the TA of the T-DU / cell to the UE. If the TA of the T-DU / cell is still valid, the UE may skip the RACH procedure at steps 431 and 432 when executing the cell switch. And at steps 433, 434, 435, 436 and 437, the UE, S-DU, T-DU and CU proceed with completion of the LTM procedure.

[0085] FIGS. 5 A and 5B are flowcharts illustrating various steps in a method 500 according to various example implementations. The method includes sending a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration (e.g., LTM candidate cell configuration) associated with at least one candidate target cell, and a configuration of random access preamble repetitions, asshown at block 502 of FIG. 5 A. The method includes receiving a measurement report from the user equipment, as shown at block 504. The method includes making at block 506 a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, sending at block 508 a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0086] In some examples, the method 500 further includes receiving the configuration of the random access preamble repetitions from the at least one candidate target cell, as shown at block 510 of FIG. 5B. In some of these examples, the method includes generating the candidate cell configuration associated with the at least one candidate target cell, as shown at block 512. And the method includes preparing the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions, as shown at block 514.

[0087] In some examples, the determination is made at block 506 to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the control command sent to the user equipment is a PDCCH order for early uplink timing advance acquisition.

[0088] In some examples, the determination is made at block 506 to trigger the random access procedure for a random access-based cell switch (e.g., random accessbased LTM cell switch) to the at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

[0089] In some examples, the control command sent to the user equipment at block 508 includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

[0090] In some examples, the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment at block 508 includes an indication to increase or decrease the number of repetitions for the random access procedure.

[0091] FIGS. 6A - 6E are flowcharts illustrating various steps in a method 600 according to various example implementations. The method includes receiving a radioresource control reconfiguration message from a radio access node that includes a candidate cell configuration (e.g., LTM candidate cell configuration) associated with at least one candidate target cell, and a configuration of random access preamble repetitions, as shown at block 602 of FIG. 6A. The method includes receiving at block 604 a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, performing at block 606 the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0092] In some examples, the control command received from the radio access node at block 604 is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

[0093] In some examples, the control command received from the radio access node at block 604 is a cell switch command to trigger the random access procedure for a random access-based cell switch (e.g., random access-based LTM cell switch) to the at least one candidate target cell.

[0094] In some examples, the control command received from the radio access node at block 604 includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, as shown in FIG. 6B. In some of these examples, performing the random access procedure at block 606 includes sending at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication, as shown at block 608.

[0095] In some examples, the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node at block 604 includes an indication to increase or decrease the number of repetitions for the random access procedure, as shown in FIG. 6C. In some of these examples, performing the random access procedure at block 606 includes sending at least one random access preamble with an increase or decrease in the number of repetitions based on the indication, as shown at block 610.

[0096] In some examples, the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions.In some of these examples, the control command received from the radio access node at block 604 indicates retransmission of at least one random access preamble, as shown in FIG. 6D. Also in some of these examples, the method 600 further includes determining that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached, as shown at block 612. Tthe method includes increasing the number of repetitions to an increased number of repetitions, as shown at block 614. And performing the random access procedure at block 606 includes sending the at least one random access preamble in a retransmission with the increased number of repetitions, as shown at block 616.

[0097] In some examples, the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions. In some of these examples, the method 600 further includes performing one or more LI measurements, as shown at block 618 of FIG. 6E. The method includes determining a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, as shown at block 620. And performing the random access procedure at block 606 includes sending the at least one random access preamble in a retransmission with the number of repetitions as determined, as shown at block 622.

[0098] According to example implementations of the present disclosure, a telecommunications system 100 or PLMN 102, and its components such as a UE 110, gNB 206, UE 208, CU 210, DU 212, S-DU 212A and / or T-DU 212B may be implemented by various means. Means for implementing the system and its components may include hardware, firmware, software, or combinations thereof. In some examples, one or more apparatuses may be configured to function as or otherwise implement the system and its components shown and described herein. In examples involving more than one apparatus, the respective apparatuses may be connected to or otherwise in communication with one another in a number of different manners, such as directly or indirectly via a wired or wireless network or the like.

[0099] According to some example implementations, at least some of the method 500 described with respect to FIGS. 5 A and 5B may be carried out by an apparatus comprising means for performing functions corresponding steps of the method. Similarly,at least some of the method 600 described with respect to FIGS. 6A-6E may be carried out by an apparatus comprising means for performing functions corresponding steps of the method. Examples of a suitable apparatus may include a gNB (e.g., gNB-CU, gNB- DU), ng-eNB, S-DU, T-DU, CU or any suitable apparatus, such as a server, host or node. Other examples of a suitable apparatus may include a user equipment, user device, user terminal or the like.

[0100] FIG. 7 illustrates an apparatus 700 in which means for performing various functions includes hardware, alone or under direction of one or more computer programs from a computer-readable storage medium or other memory, such as computer memory, according to some example implementations of the present disclosure. Generally, an apparatus of example implementations of the present disclosure may comprise, include or be embodied in one or more fixed or portable electronic devices. Examples of suitable electronic devices include a wearable computer, mobile phone, portable computer, desktop computer, workstation computer, server (server computer) or the like. The apparatus may include one or more of each of a number of components such as, for example, processing circuitry 702 connected to computer- readable storage medium or other memory 704.

[0101] The processing circuitry 702 may be composed of one or more processors alone or in combination with one or more computer-readable storage media. The processing circuitry is generally any piece of computer hardware that is capable of processing information such as, for example, data, computer programs and / or other suitable electronic information. The processing circuitry is composed of a collection of electronic circuits some of which may be packaged as an integrated circuit or multiple interconnected integrated circuits (an integrated circuit at times more commonly referred to as a “chip”). The processing circuitry may be configured to execute computer programs, which may be stored onboard the processing circuitry or otherwise stored in the memory 704 (of the same or another apparatus).

[0102] The processing circuitry 702 may be a number of processors, a multi-core processor or some other type of processor, depending on the particular implementation. Further, the processing circuitry may be implemented using a number of heterogeneous processor systems in which a main processor is present with one or more secondaryprocessors on a single chip. As another illustrative example, the processing circuitry may be a symmetric multi-processor system containing multiple processors of the same type. In yet another example, the processing circuitry may be embodied as or otherwise include one or more ASICs, FPGAs or the like. Thus, although the processing circuitry may be capable of executing a computer program to perform one or more functions, the processing circuitry of various examples may be capable of performing one or more functions without the aid of a computer program. In either instance, the processing circuitry may be appropriately programmed to perform functions or operations according to example implementations of the present disclosure.

[0103] The memory 704 is generally any piece of computer hardware that is capable of storing information such as, for example, data, computer programs, instructions 706 (e.g., computer-readable program code) and / or other suitable information either on a temporary basis and / or a permanent basis. The memory may include volatile and / or nonvolatile memory, and may be fixed or removable. Examples of suitable memory include recording media, random access memory (RAM), read-only memory (ROM), a hard drive, a flash memory, a thumb drive, a removable computer diskette, an optical disk or some combination thereof.

[0104] The memory 704 is a non- transitory device capable of storing information.One example of a suitable memory is a computer-readable storage medium, which is distinguishable from a computer-readable transmission medium capable of carrying information from one location to another. Examples of suitable computer-readable transmission media comprise electronic carrier signals, telecommunications signals, software distribution packages, or some combination thereof. As used herein, the term “non- transitory” is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM versus ROM). A computer-readable medium as described herein generally refers to a computer-readable storage medium or computer-readable transmission medium. A computer-readable medium is any entity or device capable in which information, such as one or more computer programs or portions thereof, may be stored and carried.

[0105] In addition to the memory 704 (e.g., computer-readable storage medium), the processing circuitry 702 may also be connected to one or more interfaces for displaying,transmitting and / or receiving information. The interfaces may include a communications interface 708 and / or one or more user interfaces. The communications interface may be configured to transmit and / or receive information, such as to and / or from other apparatus(es), network(s) or the like. The communications interface may be configured to transmit and / or receive information by physical (wired) and / or wireless communications links. Examples of suitable communication interfaces include a network interface controller (NIC), wireless NIC (WNIC) or the like.

[0106] The user interfaces may include a display 710 and / or one or more user input interfaces 712. The display may be configured to present or otherwise display information to a user, suitable examples of which include a liquid crystal display (LCD), light-emitting diode (LED) display, organic LED (OLED) display, active-matrix OLED (AMOLED) or the like. The user input interfaces may be wired or wireless, and may be configured to receive information from a user into the apparatus, such as for processing, storage and / or display. Suitable examples of user input interfaces include a microphone, image or video capture device, keyboard or keypad, joystick, touch-sensitive surface (separate from or integrated into a touchscreen), biometric sensor or the like. The user interfaces may further include one or more interfaces for communicating with peripherals such as printers, scanners or the like.

[0107] Execution of the instructions 706 by the processing circuitry 702, or storage of the instructions in the memory 704, supports combinations of operations for implementing example implementations of the present disclosure. In this manner, an apparatus 700 may comprise at least one processing circuitry and at least one memory coupled to the at least one processing circuitry, where the at least one processing circuitry is configured to execute instructions stored in the at least one memory. It will also be understood that one or more functions, and combinations of functions, may be implemented by special purpose hardware-based computer systems and / or processing circuitry which perform the specified functions, or combinations of special purpose hardware and program code instructions.

[0108] Some example implementations of the present disclosure may also be carried out in the form of a computer process defined by one or more computer programs or portions thereof. Example implementations of the present disclosure may be carried outby executing at least one portion of a computer program comprising instructions. The computer program may be in source code form, object code form, or in some intermediate form. The computer program may be stored in a computer-readable medium that is readable by a computer, processing circuitry or other suitable apparatus. As indicated above, for example, the computer program may be stored in a memory, such as a computer-readable storage medium. Additionally or alternatively, for example, the computer program may be stored in a computer-readable transmission medium. The coding of software for carrying out example implementations of the present disclosure is well within the scope of a person of ordinary skill in the art.

[0109] As will be appreciated, any suitable instructions may be loaded onto a computer, a processing circuitry or other programmable apparatus from a memory or a computer-readable medium (e.g., computer-readable storage medium, computer-readable transmission medium) to produce a particular machine, such that the particular machine becomes a means for implementing the functions specified herein. The instructions may also be stored in a computer-readable medium that can direct a computer, a processing circuitry or other programmable apparatus to function in a particular manner to thereby generate a particular machine or particular article of manufacture. In some examples, the instructions stored in the computer-readable medium may produce an article of manufacture, where the article of manufacture becomes a means for implementing functions described herein. The instructions may be retrieved from a computer-readable medium and loaded into a computer, processing circuitry or other programmable apparatus to configure the computer, processing circuitry or other programmable apparatus to execute operations to be performed on or by the computer, processing circuitry or other programmable apparatus.

[0110] Retrieval, loading and execution of instructions comprising program code instructions may be performed sequentially such that one instruction is retrieved, loaded and executed at a time. In some example implementations, retrieval, loading and / or execution may be performed in parallel such that multiple instructions are retrieved, loaded, and / or executed together. Execution of the program code instructions may produce a computer-implemented process such that the instructions executed by thecomputer, processing circuitry or other programmable apparatus provide operations for implementing functions described herein.

[0111] As explained above and reiterated below, the present disclosure includes, without limitation, the following example implementations.

[0112] Clause 1. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: send a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a measurement report from the user equipment; make a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, send a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0113] Clause 2. The apparatus of clause 1 , wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: receive the configuration of the random access preamble repetitions from the at least one candidate target cell; generate the candidate cell configuration associated with the at least one candidate target cell; and prepare the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

[0114] Clause 3. The apparatus of clause 1 or clause 2, wherein the determination is made to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the control command sent to the user equipment is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition.

[0115] Clause 4. The apparatus of any of clauses 1 to 3, wherein the determination is made to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

[0116] Clause 5. The apparatus of any of clauses 1 to 4, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

[0117] Clause 6. The apparatus of any of clauses 1 to 5, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

[0118] Clause 7. An apparatus comprising: means for sending a radio resource control reconfiguration message to an user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; means for receiving a measurement report from the user equipment; means for making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, means for sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0119] Clause 8. The apparatus of clause 7, wherein the apparatus further comprises: means for receiving the configuration of the random access preamble repetitions from the at least one candidate target cell; means for generating the candidate cell configuration associated with the at least one candidate target cell; and means for preparing the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

[0120] Clause 9. The apparatus of clause 7 or clause 8, wherein the determination is made to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the control command sent to the user equipment is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition.

[0121] Clause 10. The apparatus of any of clauses 7 to 9, wherein the determination is made to trigger the random access procedure for a random access-based cell switch tothe at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

[0122] Clause 11. The apparatus of any of clauses 7 to 10, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

[0123] Clause 12. The apparatus of any of clauses 7 to 11, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

[0124] Clause 13. A method comprising: sending a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a measurement report from the user equipment; making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0125] Clause 14. The method of clause 13, wherein the method further comprises: receiving the configuration of the random access preamble repetitions from the at least one candidate target cell; generating the candidate cell configuration associated with the at least one candidate target cell; and preparing the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

[0126] Clause 15. The method of clause 13 or clause 14, wherein the determination is made to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the control command sent to the user equipment is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition.

[0127] Clause 16. The method of any of clauses 13 to 15, wherein the determination is made to trigger the random access procedure for a random access-based cell switch tothe at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

[0128] Clause 17. The method of any of clauses 13 to 16, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

[0129] Clause 18. The method of any of clauses 13 to 17, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

[0130] Clause 19. A computer-readable storage medium that is non- transitory and has instructions stored therein that, in response to execution by at least one processing circuitry, causes an apparatus to at least: send a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a measurement report from the user equipment; make a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, send a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0131] Clause 20. The computer-readable storage medium of clause 19, wherein the computer-readable storage medium has further instructions stored therein that, in response to execution by the at least one processing circuitry, causes the apparatus to further at least: receive the configuration of the random access preamble repetitions from the at least one candidate target cell; generate the candidate cell configuration associated with the at least one candidate target cell; and prepare the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

[0132] Clause 21. The computer-readable storage medium of clause 19 or clause 20, wherein the determination is made to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the controlcommand sent to the user equipment is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition.

[0133] Clause 22. The computer-readable storage medium of any of clauses 19 to 21, wherein the determination is made to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

[0134] Clause 23. The computer-readable storage medium of any of clauses 19 to 22, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

[0135] Clause 24. The computer-readable storage medium of any of clauses 19 to 23, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

[0136] Clause 25. An apparatus comprising means for performing the method of any of clauses 13 to 18.

[0137] Clause 26. A computer-readable medium comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 13 to 18.

[0138] Clause 27. A computer-readable storage medium comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 13 to 18.

[0139] Clause 28. A computer program comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 13 to 18.

[0140] Clause 29. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a control command fromthe radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0141] Clause 30. The apparatus of clause 29, wherein the control command received from the radio access node is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

[0142] Clause 31. The apparatus of clause 29 or clause 30, wherein the control command received from the radio access node is a cell switch command to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell.

[0143] Clause 32. The apparatus of any of clauses 29 to 31, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

[0144] Clause 33. The apparatus of any of clauses 29 to 32, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

[0145] Clause 34. The apparatus of any of clauses 29 to 33, wherein the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: determine that the maximum number ofretransmissions for the number of repetitions for the at least one random access preamble has been reached; and increase the number of repetitions to an increased number of repetitions, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the increased number of repetitions.

[0146] Clause 35. The apparatus of any of clauses 29 to 34, wherein the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions, and wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: perform one or more LI measurements; and determine a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the number of repetitions as determined.

[0147] Clause 36. An apparatus comprising: means for receiving a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; means for receiving a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, means for performing the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0148] Clause 37. The apparatus of clause 36, wherein the control command received from the radio access node is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

[0149] Clause 38. The apparatus of clause 36 or clause 37, wherein the control command received from the radio access node is a cell switch command to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell.

[0150] Clause 39. The apparatus of any of clauses 36 to 38, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein the means for performing the random access procedure includes means for sending at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

[0151] Clause 40. The apparatus of any of clauses 36 to 39, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein the means for performing the random access procedure includes means for sending at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

[0152] Clause 41. The apparatus of any of clauses 36 to 40, wherein the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the apparatus further comprises: means for determining that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached; and means for increasing the number of repetitions to an increased number of repetitions, and wherein the means for performing the random access procedure includes means for sending the at least one random access preamble in a retransmission with the increased number of repetitions.

[0153] Clause 42. The apparatus of any of clauses 36 to 41, wherein the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions, and wherein the apparatus further comprises: means for performing one or more LI measurements; and means for determining a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein the means for performing the random access procedure includes means for sending the at least one random access preamble in a retransmission with the number of repetitions as determined.

[0154] Clause 43. A method comprising: receiving a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, performing the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0155] Clause 44. The method of clause 43, wherein the control command received from the radio access node is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

[0156] Clause 45. The method of clause 43 or clause 44, wherein the control command received from the radio access node is a cell switch command to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell.

[0157] Clause 46. The method of any of clauses 43 to 45, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein performing the random access procedure includes sending at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

[0158] Clause 47. The method of any of clauses 43 to 46, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein performing the random access procedure includes sending at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

[0159] Clause 48. The method of any of clauses 43 to 47, wherein the configuration of the random access preamble repetitions indicates a maximum number ofretransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the method further comprises: determining that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached; and increasing the number of repetitions to an increased number of repetitions, and wherein performing the random access procedure includes sending the at least one random access preamble in a retransmission with the increased number of repetitions.

[0160] Clause 49. The method of any of clauses 43 to 48, wherein the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions, and wherein the method further comprises: performing one or more LI measurements; and determining a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein performing the random access procedure includes sending the at least one random access preamble in a retransmission with the number of repetitions as determined.

[0161] Clause 50. A computer-readable storage medium that is non-transitory and has instructions stored therein that, in response to execution by at least one processing circuitry, causes an apparatus to at least: receive a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

[0162] Clause 51. The computer-readable storage medium of clause 50, wherein the control command received from the radio access node is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

[0163] Clause 52. The computer-readable storage medium of clause 50 or clause 51, wherein the control command received from the radio access node is a cell switch command to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell.

[0164] Clause 53. The computer-readable storage medium of any of clauses 50 to 52, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

[0165] Clause 54. The computer-readable storage medium of any of clauses 50 to 53, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

[0166] Clause 55. The computer-readable storage medium of any of clauses 50 to 54, wherein the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the computer-readable storage medium has further instructions stored therein that, in response to execution by the at least one processing circuitry, causes the apparatus to further at least: determine that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached; and increase the number of repetitions to an increased number of repetitions, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the increased number of repetitions.

[0167] Clause 56. The computer-readable storage medium of any of clauses 50 to 55, wherein the configuration of the random access preamble repetitions indicates layer 1(LI) measurement thresholds associated with respective numbers of repetitions, and wherein the computer-readable storage medium has further instructions stored therein that, in response to execution by the at least one processing circuitry, causes the apparatus to further at least: perform one or more LI measurements; and determine a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the number of repetitions as determined.

[0168] Clause 57. An apparatus comprising means for performing the method of any of clauses 43 to 49.

[0169] Clause 58. A computer-readable medium comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 43 to 49.

[0170] Clause 59. A computer-readable storage medium comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 43 to 49.

[0171] Clause 60. A computer program comprising instructions that, in response to execution by at least one processing circuitry, causes an apparatus to perform the method of any of clauses 43 to 49.

[0172] Many modifications and other implementations of the disclosure set forth herein will come to mind to one skilled in the art to which the disclosure pertains having the benefit of the teachings presented in the foregoing description and the associated figures. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated figures describe example implementations in the context of certain example combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative implementations without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and / or functions than those explicitly described above are also contemplated as may be set forth in some of theappended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: send a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a measurement report from the user equipment; make a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, send a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

2. The apparatus of claim 1, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: receive the configuration of the random access preamble repetitions from the at least one candidate target cell; generate the candidate cell configuration associated with the at least one candidate target cell; and prepare the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

3. The apparatus of claim 1, wherein the determination is made to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell, and the control command sent to the user equipment is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition.

4. The apparatus of claim 1, wherein the determination is made to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell, and the control command sent to the user equipment is a cell switch command.

5. The apparatus of claim 1, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

6. The apparatus of claim 1, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

7. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receive a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

8. The apparatus of claim 7, wherein the control command received from the radio access node is a physical downlink control channel (PDCCH) order for early uplink timing advance acquisition to trigger the random access procedure for an early uplink synchronization with the at least one candidate target cell.

9. The apparatus of claim 7, wherein the control command received from the radio access node is a cell switch command to trigger the random access procedure for a random access-based cell switch to the at least one candidate target cell.

10. The apparatus of claim 7, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

11. The apparatus of claim 7, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

12. The apparatus of claim 7, wherein the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: determine that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached; and increase the number of repetitions to an increased number of repetitions, andwherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the increased number of repetitions.

13. The apparatus of claim 7, wherein the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions, and wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further at least: perform one or more LI measurements; and determine a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein the apparatus caused to perform the random access procedure includes the apparatus caused to send the at least one random access preamble in a retransmission with the number of repetitions as determined.

14. A method comprising: sending a radio resource control reconfiguration message to a user equipment that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a measurement report from the user equipment; making a determination to trigger a random access procedure of the user equipment towards the at least one candidate target cell based on the measurement report; and based on the determination, sending a control command to the user equipment to cause the user equipment to perform the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

15. The method of claim 14, wherein the method further comprises: receiving the configuration of the random access preamble repetitions from the at least one candidate target cell;generating the candidate cell configuration associated with the at least one candidate target cell; and preparing the radio resource control reconfiguration message including the candidate cell configuration and the configuration of the random access preamble repetitions.

16. The method of claim 14, wherein the control command sent to the user equipment includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure.

17. The method of claim 14, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command sent to the user equipment includes an indication to increase or decrease the number of repetitions for the random access procedure.

18. A method comprising: receiving a radio resource control reconfiguration message from a radio access node that includes a candidate cell configuration associated with at least one candidate target cell, and a configuration of random access preamble repetitions; receiving a control command from the radio access node to trigger a random access procedure towards the at least one candidate target cell; and based on the control command, performing the random access procedure based on the candidate cell configuration and the configuration of the random access preamble repetitions.

19. The method of claim 18, wherein the control command received from the radio access node includes an indication to activate or deactivate the random access preamble repetitions for the random access procedure, and wherein performing the random access procedure includes sending at least one random access preamble with the random access preamble repetitions activated or deactivated based on the indication.

20. The method of claim 18, wherein the configuration of the random access preamble repetitions indicates a number of repetitions, and the control command received from the radio access node includes an indication to increase or decrease the number of repetitions for the random access procedure, and wherein performing the random access procedure includes sending at least one random access preamble with an increase or decrease in the number of repetitions based on the indication.

21. The method of claim 18, wherein the configuration of the random access preamble repetitions indicates a maximum number of retransmissions for a number of repetitions, wherein the control command received from the radio access node indicates retransmission of at least one random access preamble, wherein the method further comprises: determining that the maximum number of retransmissions for the number of repetitions for the at least one random access preamble has been reached; and increasing the number of repetitions to an increased number of repetitions, and wherein performing the random access procedure includes sending the at least one random access preamble in a retransmission with the increased number of repetitions.

22. The method of claim 18, wherein the configuration of the random access preamble repetitions indicates layer 1 (LI) measurement thresholds associated with respective numbers of repetitions, and wherein the method further comprises: performing one or more LI measurements; and determining a number of repetitions based on the LI measurement thresholds and the one or more LI measurements, and wherein performing the random access procedure includes sending the at least one random access preamble in a retransmission with the number of repetitions as determined.

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