Handover messages comprising information for an early acquisition of a timing advance

Abstract

An apparatus for a network device, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to: transmit a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receive an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance.

Description

[0001] HANDOVER MESSAGES COMPRISING INFORMATION FOR AN EARLY ACQUISITION OF A TIMING ADVANCE

[0002] Field of the Disclosure

[0003] Various example embodiments relate to an apparatus for a network device.

[0004] Further example embodiments relate to a method for a network device.

[0005] Background

[0006] Communication systems such as, e.g., wireless communication systems may be used for wireless exchange of information between two or more entities, e.g., comprising one or more terminal device, e.g., user equipment (UE), and one or more network devices such as, e.g., base stations.

[0007] In some communication systems, handover procedures are proposed, wherein terminal devices may transition from one cell or network device, e.g., source network device, respectively, to another cell or network device, e.g., target network device, e.g., to enable mobility of users.

[0008] Summary

[0009] Various example embodiments of the disclosure are set out by the independent claims. The example embodiments and features, if any, described in this specification, that do not fall under the scope of the independent claims, are to be interpreted as examples useful for understanding various example embodiments of the disclosure.

[0010] Some examples relate to an apparatus for a network device, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to: transmit a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receive an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance. In some examples, this may enable an early acquisition of the timing advance, thus e.g. reducing latencies that may be associated with the handover.

[0011] In some examples, at least one of the network device or the further network device may adhere to and / or may be based on some accepted (and / or planned) specification, e.g., standard, such as, e.g. 3G, 4G, 5G, 6G, or some other wireless communication standard.

[0012] In some examples, at least one of the network device and the further network device may, e.g., be a base station, e.g., gNB.

[0013] In some examples, the network device may at least temporarily act, e.g., assume a role of, a source node, e.g., source gNB, for a handover. In some examples, the further network device may at least temporarily act, e.g., assume a role of, a target node, e.g., target gNB, for a handover.

[0014] In some examples, the acknowledgement further comprises at least one of: a) a physical random access channel configuration, or b) a bandwidth configuration, or c) a carrier information.

[0015] In some examples, the instructions, when executed by the at least one processor, cause the network device to: receive a measurement report from a terminal device, determine whether a handover with an early acquisition of a timing advance should be prepared based on at least one of: a) the measurement report, or b) at least one requirement of the terminal device.

[0016] In some examples, the instructions, when executed by the at least one processor, cause the network device to: transmit first information to the terminal device, the first information characterizing at least one of: a) the set of one or more preambles, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, receive second information from the further network device, the second information comprising at least one of: aa) timing advance information associated with the terminal device, or bb) a target radio resource control configuration for the terminal device. In some examples, the instructions, when executed by the at least one processor, cause the network device to: complete radio resource control reconfiguration information by including the timing advance information associated with the terminal device, transmit the radio resource control reconfiguration information to the terminal device.

[0017] Some examples relate to an apparatus for a network device, the apparatus comprising means for: transmitting a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receiving an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance.

[0018] In some examples, the means for transmitting the handover request or for receiving the acknowledgement may, e.g., comprise at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to perform at least one of the aforementioned aspects of transmitting the handover request or receiving the acknowledgement.

[0019] In some examples, the means for transmitting the handover request or for receiving the acknowledgement may, e.g., comprise circuitry configured to perform at least one of the aforementioned aspects of transmitting and / or receiving.

[0020] Some examples relate to a method for a network device, comprising: transmitting a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receiving an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance.

[0021] Some examples relate to an apparatus for a network device (e.g., for a network device at least temporarily acting as a target node for a handover), the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to: receive a handover request from a further network device (e.g., a source network device), the handover request comprising a request for an early acquisition of a timing advance, determine a set of one or more preambles for the acquisition of the timing advance, transmit an acknowledgement of the handover request to the further network device, the acknowledgement comprising the set of one or more preambles.

[0022] In some examples, the instructions, when executed by the at least one processor, cause the network device to: receive a preamble of the set of one or more preambles from a terminal device, determine second information, the second information comprising at least one of: aa) timing advance information associated with the terminal device, or bb) a target radio resource control configuration for the terminal device, transmit the second information to the further network device.

[0023] In some examples, the instructions, when executed by the at least one processor, cause the network device to perform at least one of: a) perform admission control for a potential handover of a or the terminal device from the further network device to the network device prior to transmitting the acknowledgement, or b) perform admission control for a potential handover of a or the terminal device from the further network device to the network device after receiving the preamble from the terminal device.

[0024] Some examples relate to an apparatus for a network device, the apparatus comprising means for: receiving a handover request from a further network device, the handover request comprising a request for an early acquisition of a timing advance, determining a set of one or more preambles for the acquisition of the timing advance, transmitting an acknowledgement of the handover request to the further network device, the acknowledgement comprising the set of one or more preambles.

[0025] In some examples, the means for receiving the handover request, determining a set of one or more preambles, and for transmitting the acknowledgement of the handover request may, e.g., comprise at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the network device to perform at least one of the aforementioned aspects of receiving the handover request and transmitting the acknowledgement of the handover request. In some examples, the means for receiving the handover request, determining the set of one or more preambles and for transmitting the acknowledgement of the handover request may, e.g., comprise circuitry configured to perform at least one of the aforementioned aspects of receiving the handover request and transmitting the acknowledgement.

[0026] Some examples relate to a method for a network device, comprising: receiving a handover request from a further network device, the handover request comprising a request for an early acquisition of a timing advance, determining a set of one or more preambles for the acquisition of the timing advance, transmitting an acknowledgement of the handover request to the further network device, the acknowledgement comprising the set of one or more preambles.

[0027] Some examples relate to an apparatus for a terminal device, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device to: receive first information from a network device, the first information characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmit a preamble of the set of one or more preambles to a further network device.

[0028] In some examples, the terminal device may adhere to and / or may be based on some accepted (and / or planned) specification, e.g., standard, such as, e.g. 3G, 4G, 5G, 6G, or some other wireless communication standard.

[0029] In some examples, the terminal device may be suitable for use with a wireless, e.g., cellular, communication system. In some examples, the terminal device may, for example, be a user equipment (UE) for a wireless communication system.

[0030] In some examples, the instructions, when executed by the at least one processor, cause the terminal device to: receive radio resource control reconfiguration information comprising timing advance information associated with the terminal device, execute a handover based on the radio resource control reconfiguration information.

[0031] Some examples relate to an apparatus for a terminal device, the apparatus comprising means for: receiving first information from a network device, the first information characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmitting a preamble of the set of one or more preambles to a further network device.

[0032] In some examples, the means for receiving the first information and for transmitting the preamble may, e.g., comprise at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device to perform at least one of the aforementioned aspects of receiving the first information and transmitting the preamble.

[0033] In some examples, the means for receiving the first information and for transmitting the preamble may, e.g., comprise circuitry configured to perform at least one of the aforementioned aspects of receiving the first information and transmitting the preamble.

[0034] Some examples relate to a method for a terminal device, comprising receiving first information from a network device, the first information characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmitting a preamble of the set of one or more preambles to a further network device.

[0035] Some examples relate to a network device comprising at least one apparatus according to the examples.

[0036] Some examples relate to a terminal device comprising at least one apparatus according to the examples. Some examples relate to a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least some aspects of the method according to the examples.

[0037] In some examples, the computer program may be provided on a computer readable storage medium, e.g., a non-transitory computer readable medium.

[0038] Some examples relate to a data carrier signal carrying and / or characterizing the computer program according to the example embodiments.

[0039] Brief description of the Figures

[0040] Fig. 1A schematically depicts a simplified block diagram according to some examples,

[0041] Fig. IB schematically depicts a simplified block diagram according to some examples,

[0042] Fig. 2 schematically depicts a simplified block diagram according to some examples,

[0043] Fig. 3 schematically depicts a simplified flow chart according to some examples,

[0044] Fig. 4A schematically depicts a simplified block diagram according to some examples,

[0045] Fig. 4B schematically depicts a simplified block diagram according to some examples,

[0046] Fig. 5 schematically depicts a simplified flow chart according to some examples,

[0047] Fig. 6 schematically depicts a simplified flow chart according to some examples, Fig. 7 A schematically depicts a simplified block diagram according to some examples,

[0048] Fig. 7B schematically depicts a simplified block diagram according to some examples,

[0049] Fig. 8A schematically depicts a simplified block diagram according to some examples,

[0050] Fig. 8B schematically depicts a simplified block diagram according to some examples,

[0051] Fig. 9 schematically depicts a simplified flow chart according to some examples,

[0052] Fig. 10 schematically depicts a simplified flow chart according to some examples,

[0053] Fig. 11 schematically depicts a simplified block diagram according to some examples,

[0054] Fig. 12A schematically depicts a simplified block diagram according to some examples,

[0055] Fig. 12B schematically depicts a simplified block diagram according to some examples,

[0056] Fig. 13 schematically depicts a simplified flow chart according to some examples,

[0057] Fig. 14 schematically depicts a simplified signaling diagram according to some examples,

[0058] Fig. 15 schematically depicts a simplified block diagram according to some examples. Description of some Example Embodiments

[0059] Some examples, Fig. 1A, 2, 3, relate to an apparatus 100 for a network device 10, the apparatus 100 comprising at least one processor 102, and at least one memory 104 storing instructions 106 that, when executed by the at least one processor 102, cause the network device 10 to: transmit 400 a handover request REQ-HO to a further network device 20, the handover request REQ-HO comprising a request REQ-E-TA for an early acquisition of a timing advance (e.g., for a future handover HO-E-TA of a terminal device 30 from the network device 10 to the further network device 20), receive 402 an acknowledgement ACK- HO of the handover request REQ-HO from the further network device 20, the acknowledgement ACK-HO comprising a set SET-PRE-TA of one or more preambles for the acquisition of the timing advance. In some examples, this may enable an early acquisition of the timing advance, thus e.g. reducing latencies that may be associated with the handover HO-E-TA.

[0060] In some examples, Fig. 2, at least one of the network device 10 or the further network device 20 may adhere to and / or may be based on some accepted (and / or planned) specification, e.g., standard, such as, e.g. 3G, 4G, 5G, 6G, or some other wireless communication standard.

[0061] In some examples, Fig. 2, at least one of the network device 10 and the further network device 20 may, e.g., be a base station, e.g., gNB, e.g., for a wireless communication system 1000.

[0062] In some examples, Fig. 2, the network device 10 may at least temporarily act, e.g., assume a role of, a source node, e.g., source gNB, for a handover HO-E-TA. In some examples, the further network device 20 may at least temporarily act, e.g., assume a role of, a target node, e.g., target gNB, for a handover HO-E-TA.

[0063] In some examples, Fig. 4A, the handover request REQ-HO further comprises, e.g., in addition to the request REQ-E-TA for the early acquisition of the timing advance, at least one of: a) an identifier SCID associated with a serving cell, e.g., Serving Cell ID, or b) a source configuration SRC-CFG associated with a terminal device, e.g., a UE source configuration. In some examples, Fig. 4B, the acknowledgement ACK-HO further comprises at least one of: a) a physical random access channel configuration PRACH-CFG (e.g., associated with, e.g., to be potentially used for, the early timing advance acquisition), or b) a bandwidth configuration BW-CFG, or c) a carrier information C-INF.

[0064] In some examples, Fig. 5, the instructions 106, when executed by the at least one processor 102, cause the network device 10 to: receive 410 a measurement report M- REP from a terminal device 30, determine 412 whether a handover HO-E-TA with an early acquisition of a timing advance should be prepared based on at least one of: a) the measurement report M-REP, or b) at least one requirement UE-REQ of the terminal device 30.

[0065] In some examples, the measurement report M-REP may trigger the network device 10 to transmit the handover request, see block 400 of Fig. 3.

[0066] In some examples, Fig. 5, the handover HO-E-TA may be prepared 414 based on the determination DET-HO as obtained by block 412.

[0067] In some examples, the at least one requirement UE-REQ of the terminal device 30 may, e.g., indicate one or more services associated with the terminal device 30 which may benefit from, e.g. require, comparatively low interruption times (e.g., as may be introduced by a handover), such as, e.g., augmented reality (AR) or extended reality (XR).

[0068] In some examples, the at least one requirement UE-REQ may, e.g., be derived or determined from a quality of service, QoS, e.g., of the terminal device 30, or based on a service level agreement, e.g., as configured by Operations, Administration and Maintenance (0AM), e.g., to the network device 10.

[0069] In some examples, Fig. 6, 7A, the instructions 106, when executed by the at least one processor 102, cause the network device 10 to: transmit 422 first information 1-1 to the terminal device 30, the first information 1-1 characterizing at least one of: a) the set SET-PRE-TA of one or more preambles, or b) a physical random access channel configuration PRACH-CFG, or c) a bandwidth configuration BW-CFG, or d) a carrier information C-INF, or e) a grant GR-E-TA for the early acquisition of the timing advance, receive 424 second information 1-2 from the further network device 20, the second information 1-2, Fig. 7B, comprising at least one of: aa) timing advance information I-TA-UE associated with the terminal device 30 (e.g., as determined by the further network device 20), or bb) a target radio resource control configuration T-RRC- CFG for the terminal device 30.

[0070] In some examples, Fig. 6, the instructions 106, when executed by the at least one processor 102, cause the network device 10 to: complete 426 radio resource control reconfiguration information I-RECFG by including the timing advance information I- TA-UE associated with the terminal device 30, transmit 428 the radio resource control reconfiguration information I-RECFG to the terminal device 30, e.g., in the form of a handover command.

[0071] In some examples, Fig. 6, the instructions 106, when executed by the at least one processor 102, cause the network device 10 to prepare 420 a radio resource control reconfiguration, e.g., prior to transmitting 422 the first information 1-1 to the terminal device 30. In some other examples, preamble resources, e.g., only preamble resources, may be prepared by the network device 10.

[0072] Some examples, Fig. IB, relate to an apparatus 100' for a network device 10 (Fig. 2), the apparatus 100' comprising means 102' for: transmitting 400 (Fig. 3) a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receiving 402 an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance.

[0073] In some examples, Fig. IB, the means 102' for transmitting the handover request or for receiving the acknowledgement may, e.g., comprise at least one processor 102 (Fig. 1A), and at least one memory 104 storing instructions 106 that, when executed by the at least one processor 102, cause the network device 10 to perform at least one of the aforementioned aspects of transmitting 400 the handover request or receiving 402 the acknowledgement.

[0074] In some examples, Fig. IB, the means 102' for transmitting the handover request or for receiving the acknowledgement may, e.g., comprise circuitry 104' configured to perform at least one of the aforementioned aspects of transmitting 400 and / or receiving 402.

[0075] Some examples, Fig. 3, relate to a method for a network device 10, comprising: transmitting 400 a handover request to a further network device, the handover request comprising a request for an early acquisition of a timing advance, receiving 402 an acknowledgement of the handover request from the further network device, the acknowledgement comprising a set of one or more preambles for the acquisition of the timing advance.

[0076] Some examples, Fig. 2, 8 A, 9 relate to an apparatus 200 for a network device 20 (e.g., for a network device 20 at least temporarily acting as a target node for a handover), the apparatus 200 comprising at least one processor 202, and at least one memory 204 storing instructions 206 that, when executed by the at least one processor 202, cause the network device 20 to: receive 450 a handover request REQ-HO from a further network device (e.g., a source network device) 10, the handover request REQ-HO comprising a request REQ-E-TA for an early acquisition of a timing advance, determine 452 a set SET-PRE-TA of one or more preambles for the acquisition of the timing advance, transmit 454 an acknowledgement ACK-HO of the handover request REQ-HO to the further network device 10, the acknowledgement ACK-HO comprising the set SET- PRE-TA of one or more preambles.

[0077] In some examples, Fig. 10, the instructions 206, when executed by the at least one processor 202, cause the network device 20 to: receive 460 a preamble UE-PRE of the set SET-PRE-TA of one or more preambles from a terminal device 30, determine 462 second information 1-2 (also see Fig. 7B), the second information 1-2 comprising at least one of: aa) timing advance information associated with the terminal device, or bb) a target radio resource control configuration for the terminal device, transmit 464 the second information 1-2 to the further network device 10.

[0078] In some examples, Fig. 11 , the instructions 206, when executed by the at least one processor 202, cause the network device 20 to perform at least one of: a) perform 470 admission control for a potential handover of a or the terminal device 30 from the further network device 10 to the network device 20 prior to transmitting 454 the acknowledgement ACK-HO (Fig. 9), or b) perform 472 (Fig. 11) admission control for a potential handover of the terminal device 30 from the further network device 10 to the network device 20 after receiving 460 (Fig. 10) the preamble UE-PRE from the terminal device 30.

[0079] Some examples, Fig. 8B, relate to an apparatus 200' for a network device 20, the apparatus 200' comprising means 202' for: receiving 450 a handover request from a further network device, the handover request comprising a request for an early acquisition of a timing advance, determining 452 a set of one or more preambles for the acquisition of the timing advance, transmitting 454 an acknowledgement of the handover request to the further network device, the acknowledgement comprising the set of one or more preambles.

[0080] In some examples, Fig. 8B, the means 202' for receiving 450, determining 452 and transmitting 454 may, e.g., comprise at least one processor 202 (Fig. 8A), and at least one memory 204 storing instructions 206 that, when executed by the at least one processor 202, cause the network device 20 to perform at least one of the aforementioned aspects of receiving 450, determining 452 and transmitting 454.

[0081] In some examples, Fig. 8B, the means 202' for receiving 450, determining 452 and transmitting 454 may, e.g., comprise circuitry 204' configured to perform at least one of the aforementioned aspects of receiving 450, determining 452, transmitting 454.

[0082] Some examples, Fig. 9, relate to a method for a network device 20, comprising: receiving 450 a handover request from a further network device, the handover request comprising a request for an early acquisition of a timing advance, determining 452 a set of one or more preambles for the acquisition of the timing advance, transmitting 454 an acknowledgement of the handover request to the further network device, the acknowledgement comprising the set of one or more preambles.

[0083] Some examples, 2, Fig. 12A, 13, relate to an apparatus 300 for a terminal device 30, the apparatus 300 comprising at least one processor 302, and at least one memory 304 storing instructions 306 that, when executed by the at least one processor 302, cause the terminal device 30 to: receive 490 first information 1-1 from a network device 10, the first information 1-1 (see, for example, also Fig, 7A) characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmit 492 a preamble UE-PRE of the set of one or more preambles to a further network device 20.

[0084] In some examples, the transmission 492 of the preamble UE-PRE towards the further network device 20 is triggered by the receipt 490 of the first information 1-1.

[0085] In some examples the transmission of the preamble UE-PRE is triggered by at least one of: a) a measurement the terminal device, e.g., UE, 30 monitors, or b) through a, for example separate, indication, e.g., coming from the further network device 20.

[0086] In some examples, Fig. 2, the terminal device 30 may adhere to and / or may be based on some accepted (and / or planned) specification, e.g., standard, such as, e.g. 3G, 4G, 5G, 6G, or some other wireless communication standard.

[0087] In some examples, the terminal device 30 may be suitable for use with a wireless, e.g., cellular, communication system 1000. In some examples, the terminal device 30 may, for example, be a user equipment (UE) for a wireless communication system.

[0088] In some examples, Fig. 13, the instructions 306, when executed by the at least one processor 302, cause the terminal device 30 to: receive 494 radio resource control reconfiguration information I-RECFG comprising timing advance information associated with the terminal device 30, execute 496 a handover HO-E-TA, e.g., from the network device 10 to the network device 20, based on the radio resource control reconfiguration information I-RECFG.

[0089] In some examples, the terminal device 30 may send or transmit a preamble UE-PRE according to a pre-configuration, e.g., to initiate a handover procedure towards a target cell, e.g., associated with the further network device 20. In some examples, the preconfiguration for the preamble UE-PRE may be effected by or determined based on the received first information 1-1, see, for example, block 490 of Fig. 13. In some other examples, the pre-configuration may be effected in another way, e.g., not necessarily involving reception of the first information 1-1.

[0090] Some examples, Fig. 12B, relate to an apparatus 300' for a terminal device 30, the apparatus 300' comprising means 302' for: receiving 490 first information from a network device, the first information characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmitting 492 a preamble of the set of one or more preambles to a further network device.

[0091] In some examples, Fig. 12B, the means 302' for receiving the first information and for transmitting the preamble may, e.g., comprise at least one processor 320 (see, for example, Fig. 12A), and at least one memory 304 storing instructions 306 that, when executed by the at least one processor 302, cause the terminal device 30 to perform at least one of the aforementioned aspects of receiving 490 the first information and transmitting 492 the preamble.

[0092] In some examples, Fig. 12B, the means 302' for receiving the first information and for transmitting the preamble may, e.g., comprise circuitry 304' configured to perform at least one of the aforementioned aspects of receiving the first information and transmitting the preamble. Some examples, Fig. 13, relate to a method for a terminal device 30, comprising receiving 490 first information from a network device, the first information characterizing at least one of: a) a set of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration, or c) a bandwidth configuration, or d) a carrier information, or e) a grant for the early acquisition of the timing advance, transmitting 492 a preamble of the set of one or more preambles to a further network device.

[0093] Some examples, Fig. 2, relate to a network device 10, 20 comprising at least one apparatus 100, 100', 200, 200' according to the examples.

[0094] Some examples, Fig. 2, relate to a terminal device 30 comprising at least one apparatus 300, 300' according to the examples.

[0095] Fig. 14 schematically depicts a simplified signaling diagram according to some examples. Element El symbolizes a terminal device, e.g., UE. Element E2 symbolizes a source node, e.g., source gNB. Element E3 symbolizes a target node, e.g., target gNB. Element E4 symbolizes user plane function(s) (UPF). Element E5 symbolizes an Access and Mobility Management Function (AMF).

[0096] In some examples, at least some aspects of Fig. 14 can be used for a, for example RACH-less, baseline handover of the UE El from source node E2 to target node E3 with an early timing advance acquisition.

[0097] In some examples, the UE El may be served by source node E2 and may measure a channel quality for neighbor cells such as, e.g., provided by potential target node E3. In some examples, the UE El may get triggered, see element E10, to send a measurement report, see arrow al, by e.g., an A3 threshold -3dB measurement difference between source node and target node.

[0098] In some examples, e.g., based on received measurements and, optionally, based on one or more UE requirements (such as, e.g., low interruption time requiring services such as AR / XR, e.g., known from the QoS of the UE El or SLA(s) configured, e.g., by 0AM to the source node e2), the source node E2 may trigger, see element Ell, a, for example baseline, handover, e.g., with early timing advance (TA) acquisition.

[0099] In some examples, the source node E2 may send a handover request, see arrow a2, to the target node E3, e.g., via an Xn interface, e.g., including serving cell ID(s) and a source configuration of the UE El.

[0100] In some examples, such source configuration of the UE may be treated as a reference configuration, e.g., by the target node E3, e.g., when it prepares a Radio Resource Control (RRC) Reconfig configuration, see, for example, element E13 of Fig. 14, e.g., to admit the UE El, e.g., at a later point in time.

[0101] In some examples, the receipt of the measurement report al may trigger the source node E2 to transmit the handover request a2.

[0102] In some examples, Fig. 14, the handover request a2 also contains an early TA acquisition request, see, for example, element REQ-E-TA of Fig. 4A. In some examples, Fig. 14, e.g., since it has been decided to perform early TA acquisition, the handover request a2 does not directly trigger handover. Instead, in some examples, based on such handover request a2, the target node E3 may infer that a, for example fresh, TA value is to be acquired, e.g., for the UE El, e.g., to conduct RACH-less baseline handover. In some examples, for such early acquisition of a TA value, the target node E3 may allocate at least one preamble for executing the TA acquisition, see block E12 of Fig. 14.

[0103] In some examples, e.g., at this point, see block E12, the target node E3 may, e.g. also, allocate radio resource(s) to the UE El, e.g., via admission control, e.g., for a potential handover. However, as, in some examples, such resource allocation (e.g., in block E12) may result in a comparatively long reservation of such resources, in some examples, e.g., alternatively, the admission control can be postponed to, e.g., performed at, a later stage, e.g., in block E15, e.g., for optimizing a resource management. Details for the admission control related to block E15 of Fig. 14 will be provided further below. In some examples, e.g., after allocation E12 of at least one TA preamble, the target node E3 may acknowledge the handover request a2, e.g., by sending a handover acknowledge message a3 to the source node E2. In some examples, the handover acknowledge message a3 may contain a set of one or more preambles for the TA acquisition, as well as, optionally, a configuration for contention-free random access, CFRA. In some examples, e.g., along with the set of one or more preambles, the target node E3 may, e.g., also, provide at least one of a, for example detailed, PRACH configuration, or bandwidth configuration, or carrier information, e.g., to be potentially used by the UE El, e.g., for early timing advance acquisition.

[0104] In some examples, the source node E2 receives the set of one or more TA preambles and, optionally, PRACH and, optionally, other related configurations, see block E13. In some examples, e.g., subsequently, the source node E2 may initiate an early acquisition of TA, as symbolized by bracket E6 of Fig 14.

[0105] In some examples, aspects of an RRC Reconfiguration preparation by the source node E2, e.g., based on the received handover acknowledge message a3, are symbolized by block El 3. In some examples, the RRC Reconfiguration preparation by the source node E2 may be continued later, e.g., at block E16, detail examples of which will be provided further below.

[0106] In some examples, the set of one or more TA preambles and, optionally, PRACH and, optionally, other related configurations may be forwarded to the UE El, see arrow a4, e.g., in the form of an RRC Reconfiguration message, e.g. containing an early TA acquisition grant.

[0107] In some examples, a reception of such RRC Reconfiguration message does not trigger the handover for the UE El, nor does it change, e.g., the UE’s current source configuration.

[0108] In some examples, the UE El, e.g., upon receiving such grant a4, may send an acknowledgement a5 to the source node E2, e.g., if the UE El can decode the information for early access as, e.g., provided within the RRC Reconfiguration message a4.

[0109] In some examples, the reception of the acknowledgement a5 by the source node E2 may trigger the handover HO-E-TA.In some examples, upon receiving the grant a4, the UE El may trigger an early TA acquisition process, see, for example block E14, e.g., by transmitting a TA preamble towards the target node E3, see arrow a6.

[0110] In some examples, see block E15, the target node E3 detects and associates the received TA preamble, e.g., with a former context, as, e.g., fixed by the receipt of the handover request a2.

[0111] In some examples, e.g., using the TA preamble received from the UE El, the target node E3 may determine, e.g., compute, a timing advance applicable for the UE El of interest.

[0112] In some examples, the target node E3 may, e.g. also, prepare an RRC configuration, see block E15 of Fig. 14, that the UE El may need to apply, e.g., while accessing the target node E3, e.g., once the handover is triggered.

[0113] In some examples, the target node E3 may prepare an RRC Reconfiguration configuration, e.g., based on a source configuration it received earlier, see, for example, arrow a2. In some examples, e.g., if the source configuration gets modified meanwhile (e.g., between arrow a2 and block E15), the source node E2 may indicate the modification to the target node E3. In some examples, the target node E3 may send the TA information, see arrow a7, e.g., along with the target RRC configuration, to the source node E2.

[0114] In some examples, e.g., as an alternative to conduct the admission control for the UE El at the target node E3 at block El 2, the admission control for the UE El may optionally be performed at block El 5. In some examples, a motivation for this alternative may be that, if the UE El fails to decode the RRC Reconfiguration message, see arrow a4, e.g., to retrieve the early TA acquisition preambles, and therefore the UE El cannot perform early TA acquisition, resources allocated at block E12 may remain unused and may therefore be wasted.

[0115] In some examples, at block El 6, an RRC Reconfiguration preparation may be concluded, e.g., by including an acquired TA metric as, e.g., obtained from the target node E3.

[0116] In some examples, e.g., after aspects a4, a5, E14, a6, E15, a7 are executed, the source node E2 may transfer the received TA information and RRC reconfiguration, e.g., in the form of a handover command, to the UE El, see arrow a8 of Fig. 14.

[0117] In some examples, the network, e.g., source node E2, may, e.g., inherently, check for validity of the TA information, e.g., before sending handover command a8. In some examples, such TA information may only be sent if the TA remains valid. Otherwise, in some examples, the source node E2 may instruct the UE El to, e.g., perform a random access, e.g., from scratch.

[0118] In some examples, the handover command a8 may act as a trigger to the UE El to execute cell switch, e.g., to perform the handover from the source node E2 to the target node E3.

[0119] In some examples, after sending the handover command a8 to the UE El, the source node E2 may stop transmi t / receive operations (tx / rx) associated with the UE El, see block El 7, and may start source node status transfer a9 and / or data forwarding alO to the target node E3.

[0120] In some examples, e.g., upon receiving the handover command a8, the UE El directly executes cell switch, e.g., a baseline handover, see block E18. In some examples, e.g., once the UE El can successfully apply the RRC Reconfiguration message, it may send an RRC Reconfiguration complete message al l, e.g., directly to the target node E3.

[0121] In some examples, after receiving the RRC Reconfiguration complete message al l, the target node E3 sends a NGAP path switch request al3 to the core, e.g., element E5, which is duly acknowledged, see arrow al4, e.g., marking a success of the handover. In some examples, meanwhile, the UE El may start sending uplink packets al2 to the target node E3. However, in some examples, the uplink packets al 2 to the target node E3 may be buffered at target node E3, e.g., until receipt of the NGAP path request acknowledgement al4, before being delivered to the user plane function E4, see arrow al5.

[0122] In some examples, the target node E3 may provide a UE context release message al 6 to the source node, e.g., indicating that the handover was successful and the path switch has been done, wherein the source node E2 may stop data forwarding.

[0123] In some examples, e.g., in one alternative implementation, the target node E3 can provide a full RRC configuration, e.g., at elements E12, a3, E13, a4, and, for example only, the TA value via elements E15, a7, E16, a8. In that case, in some examples, message a8 may be an RRC message containing, for example, only a TA value for the cell change.

[0124] Some examples, Fig. 15, relate to a computer program PRG comprising instructions INSTR which, when executed by an apparatus, e.g., at least one of apparatus 100, or 100', or 200, or 200', or 300, or 300', cause the apparatus to perform at least some aspects of the method according to the example embodiments.

[0125] In some examples, Fig. 15, the computer program PRG may be provided on a computer readable storage medium SM, e.g., a non-transitory computer readable medium.

[0126] Some examples, Fig. 19, relate to a data carrier signal DCS carrying and / or characterizing the computer program PRG according to the example embodiments.

[0127] In some conventional systems, mobility procedures due to re-configuration of a user equipment from a configuration of a source cell to a configuration of the target cell, may involve interruptions, e.g., until the target cell configuration is fully applied and the link is established. In some conventional approaches, one part of such configuration change is to obtain and use a timing advance of the target cell. In some conventional approaches, this procedure related to obtaining the timing advance may result in additional interruption time ranging, e.g., from 10s of ms (millisecond) delay to 100s of ms, depending, e.g., on at least one of radio conditions, or random access channel load, or random access channel configurations. In some approaches, such comparatively long interruption time is not acceptable, e.g., for some latency critical applications. Thus, in some examples, a reduced interruption time may be attained by determining the timing advance between the UE and the target node prior to the cell switch.

Claims

Claims1. An apparatus (100) for a network device (10), the apparatus (100) comprising at least one processor (102), and at least one memory (104) storing instructions (106) that, when executed by the at least one processor (102), cause the network device (10) to: transmit (400) a handover request (REQ-HO) to a further network device (20), the handover request (REQ-HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, receive (402) an acknowledgement (ACK-HO) of the handover request (REQ-HO) from the further network device (20), the acknowledgement (ACK-HO) comprising a set (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance.

2. The apparatus (100) according to claim 1, wherein the acknowledgement (ACK- HO) further comprises at least one of: a) a physical random access channel configuration (PRACH-CFG), or b) a bandwidth configuration (BW-CFG), or c) a carrier information (C-INF).

3. The apparatus (100) according to any of the preceding claims, wherein the instructions (106), when executed by the at least one processor (102), cause the network device (10) to: receive (410) a measurement report (M-REP) from a terminal device (30), determine (412) whether a handover (HO-E-TA) with an early acquisition of a timing advance should be prepared based on at least one of: a) the measurement report (M-REP), or b) at least one requirement (UE- REQ) of the terminal device (30).

4. The apparatus (100) according to any of the preceding claims, wherein the instructions (106), when executed by the at least one processor (102), cause the network device (10) to: transmit (422) first information (1-1) to the terminal device (30), the first information (1-1) characterizing at least one of: a) the set (SET-PRE-TA) of one or more preambles, or b) a physical random access channel configuration (PRACH-CFG), or c) a bandwidth configuration (BW-CFG), or d) a carrier information (C-INF), or e) a grant (GR-E-TA) for the early acquisition of the timing advance, receive (424) second information (1-2) from the further network device (20), the second information (1-2) comprising at least one of: aa) timing advance information (I-TA-UE) associated with the terminal device (30), or bb) a target radio resource control configuration (T-RRC-CFG) for the terminal device (30).

5. The apparatus (100) according to claim 4, wherein the instructions (106), when executed by the at least one processor (102), cause the network device (10) to: complete (426) radio resource control reconfiguration information (I-RECFG) by including the timing advance information (I-TA-UE) associated with the terminal device (30), transmit (428) the radio resource control reconfiguration information (I-RECFG) to the terminal device (30).

6. An apparatus (100') for a network device (10), the apparatus (100') comprising means (102') for: transmitting (400) a handover request (REQ-HO) to a further network device (20), the handover request (REQ-HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, receiving (402) an acknowledgement (ACK-HO) of the handover request (REQ-HO) from the further network device (20), the acknowledgement (ACK-HO) comprising a set (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance.

7. A method for a network device (10), comprising: transmitting (400) a handover request (REQ-HO) to a further network device (20), the handover request (REQ- HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, receiving (402) an acknowledgement (ACK-HO) of the handover request (REQ-HO) from the further network device (20), the acknowledgement (ACK-HO) comprising a set (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance.

8. An apparatus (200) for a network device (20), the apparatus (200) comprising at least one processor (202), and at least one memory (204) storing instructions(206) that, when executed by the at least one processor (202), cause the network device (20) to: receive (450) a handover request (REQ-HO) from a further network device (10), the handover request (REQ-HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, determine (452) a set (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance, transmit (454) an acknowledgement (ACK-HO) of the handover request (REQ-HO) to the further network device (20), the acknowledgement (ACK-HO) comprising the set (SET-PRE-TA) of one or more preambles.

9. The apparatus (200) according to claim 8, wherein the instructions (206), when executed by the at least one processor (202), cause the network device (20) to: receive (460) a preamble (UE-PRE) of the set (SET-PRE-TA) of one or more preambles from a terminal device (30), determine (462) second information (I- 2), the second information (1-2) comprising at least one of: aa) timing advance information (I-TA-UE) associated with the terminal device (30), or bb) a target radio resource control configuration (T-RRC-CFG) for the terminal device (30), transmit (464) the second information (1-2) to the further network device (10).

10. The apparatus (200) according to any of the claims 8 to 9, wherein the instructions (206), when executed by the at least one processor (202), cause the network device (20) to perform at least one of: a) perform (470) admission control for a potential handover of a or the terminal device (30) from the further network device (10) to the network device (20) prior to transmitting (454) the acknowledgement (ACK-HO), or b) perform (472) admission control for a potential handover of a terminal device (30) from the further network device (10) to the network device (20) after receiving (460) the preamble (UE-PRE) from the terminal device (30).

11. An apparatus (200') for a network device (20), the apparatus (200') comprising means (202') for: receiving (450) a handover request (REQ-HO) from a further network device (10), the handover request (REQ-HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, determining (452) aset (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance, transmitting (454) an acknowledgement (ACK-HO) of the handover request (REQ-HO) to the further network device (20), the acknowledgement (ACK-HO) comprising the set (SET-PRE-TA) of one or more preambles.

12. A method for a network device (20), comprising: receiving (450) a handover request (REQ-HO) from a further network device (10), the handover request (REQ-HO) comprising a request (REQ-E-TA) for an early acquisition of a timing advance, determining (452) a set (SET-PRE-TA) of one or more preambles for the acquisition of the timing advance, transmitting (454) an acknowledgement (ACK-HO) of the handover request (REQ-HO) to the further network device (20), the acknowledgement (ACK-HO) comprising the set (SET- PRE-TA) of one or more preambles.

13. An apparatus (300) for a terminal device (30), the apparatus (300) comprising at least one processor (302), and at least one memory (304) storing instructions (306) that, when executed by the at least one processor (302), cause the terminal device (30) to: receive (490) first information (1-1) from a network device (10), the first information (1-1) characterizing at least one of: a) a set (SET-PRE-TA) of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration (PRACH-CFG), or c) a bandwidth configuration (BW-CFG), or d) a carrier information (C-INF), or e) a grant (GR-E-TA) for the early acquisition of the timing advance, transmit (492) a preamble (UE-PRE) of the set (SET-PRE-TA) of one or more preambles to a further network device (20).

14. The apparatus (300) according to claim 13, wherein the instructions (306), when executed by the at least one processor (302), cause the terminal device (30) to: receive (494) radio resource control reconfiguration information (I-RECFG) comprising timing advance information (I-TA-UE) associated with the terminal device (30), execute (496) a handover based on the radio resource control reconfiguration information (I-RECFG).

15. An apparatus (300') for a terminal device (30), the apparatus (300') comprising means (302') for: receiving (490) first information (1-1) from a network device (10), the first information (1-1) characterizing at least one of: a) a set (SET-PRE- TA) of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration (PRACH-CFG), or c) a bandwidth configuration (BW-CFG), or d) a carrier information (C-INF), or e) a grant (GR-E-TA) for the early acquisition of the timing advance, transmitting (492) a preamble (UE-PRE) of the set (SET-PRE-TA) of one or more preambles to a further network device (20).

16. A method for a terminal device (30), comprising receiving (490) first information (1-1) from a network device (10), the first information (1-1) characterizing at least one of: a) a set (SET-PRE-TA) of one or more preambles for an early acquisition of a timing advance, or b) a physical random access channel configuration (PRACH-CFG), or c) a bandwidth configuration (BW- CFG), or d) a carrier information (C-INF), or e) a grant (GR-E-TA) for the early acquisition of the timing advance, transmitting (492) a preamble (UE-PRE) of the set (SET-PRE-TA) of one or more preambles to a further network device (20).

17. A network device (10, 20) comprising at least one apparatus (100; 100'; 200; 200') according to at least one of the claims 1 to 6 or 8 to 11.

18. A terminal device (30) comprising at least one apparatus (300; 300') according to at least one of the claims 13 to 15.

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