Distributed configuration signaling

Abstract

Example embodiments of the present disclosure relate to methods, apparatuses, and a computer readable storage medium for enabling distributed configuration signaling. In some embodiments, the present disclosure may include a partial radio resource control (RRC) configuration that is transmitted by a central apparatus and received by a user equipment. The partial RRC configuration may include at least a first configuration part associated with the central apparatus and a second configuration part having at least one placeholder associated with a distributed apparatus. The first configuration part may include parameters configured by the central apparatus. The at least one placeholder may designate the second configuration part for parameters configured by the distributed apparatus.

Description

DISTRIBUTED CONFIGURATION SIGNALINGFIELD:

[0001] Example embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, apparatuses, and computer readable storage media for performing distributed configuration signaling within a wireless network environment.BACKGROUND:

[0002] Examples of mobile or wireless telecommunication systems may include the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE- Advanced (LTE- A), MulteFire, LTE-A Pro, fifth generation (5G) radio access technology or new radio (NR) access technology, sixth generation (6G) radio access technology, and / or beyond.

[0003] With respect to 5G, network enhancements were driven with respect to latency, throughput, and spectral efficiency. With the advent of 6G and beyond, network enhancements may be pushed even further, so there is a need to facilitate gains in network performance.SUMMARY:

[0004] According to a first embodiment, a central apparatus of a network node is provided. The central apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the central apparatus at least to transmit, to a user equipment, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus of the network node, the second configuration part including a placeholder for the distributed apparatus; and transmit, to the distributed apparatus, information relating to the placeholder of the second configuration part.

[0005] In a variant, the information relating to the placeholder may include one or more of an identifier of the placeholder, a size of the placeholder, a parameter for the placeholder to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder, an indication of one or more parametersconfigured by the central apparatus to be transmitted to the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, or an indication that the distributed apparatus should expect an acknowledgement from the user equipment

[0006] In a variant, the central apparatus may further be caused to transmit, to the user equipment with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

[0007] In another variant, the placeholder may be configured for one or more lower layer parameters to be provided by the distributed apparatus.

[0008] In another variant, the partial RRC configuration may be transmitted to the user equipment in separate RRC messages, the first configuration part being transmitted in a first RRC message and the second configuration part being transmitted in a second RRC message.

[0009] In another variant, the first configuration part and the second configuration part of the partial RRC configuration may be interleaved in a single RRC message and transmitted to the user equipment.

[0010] In another variant, the information relating to the placeholder may indicate one or more configuration elements within the second configuration part to be updated by the distributed apparatus

[0011] In another variant, the second configuration part may include a transaction identifier for tracing configuration signaling errors associated with the distributed apparatus.

[0012] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0013] In another variant, the central apparatus may further be caused to determine whether the user equipment supports partial RRC configurations prior to transmitting the partial RRC configuration.

[0014] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0015] In another variant, the central apparatus may further be caused to transmit, to the distributed apparatus, a query relating to the second configuration part.

[0016] In another variant, the central apparatus may further be caused to receive, from the distributed apparatus, an update relating to the second configuration part.

[0017] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of a complete RRC configuration including the first configuration part and the second configuration part.

[0018] According to a second embodiment, a distributed apparatus of a network node is provided. The distributed apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the distributed apparatus at least to receive, from a central apparatus of the network node, information relating to a partial radio resource control (RRC) configuration for a user equipment, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with the distributed apparatus, the second configuration part including a placeholder for the distributed apparatus; determine one or more parameters to be used by the user equipment for the placeholder of the second configuration part; transmit, to the user equipment, the one or more parameters; and receive, from the user equipment, a message acknowledging receipt of the one or more parameters.

[0019] In a variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, the one or more parameters for the placeholder to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder, an indication of one or more parameters configured by the central apparatus to be transmitted to the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, or an indication that the distributed apparatus should expect an acknowledgement from the user equipment.

[0020] In another variant, the one or more parameters may include lower layer parameters configured for the user equipment.

[0021] In another variant, the information relating to the partial RRC configuration may indicate one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

[0022] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0023] In another variant, the distributed apparatus may further be caused to receive, from the central apparatus, a query relating to the second configuration part.

[0024] In another variant, the distributed apparatus may further be caused to transmit, to the central apparatus, an update relating to the second configuration part.

[0025] In another variant, the distributed apparatus may further be caused to transmit, to the user equipment with the one or more parameters, an identifier of the distributed apparatus, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

[0026] In another variant, the distributed apparatus may further be caused to transmit, to the user equipment, one or more further parameters to be used for updating the second configuration part; and receive, from the user equipment, a message acknowledging receipt of the one or more further parameters.

[0027] According to a third embodiment, a user equipment is provided. The user equipment may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment at least to receive, from a central apparatus of a network node, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus of the network node, the second configuration part including a placeholder for the distributed apparatus; receive, from the distributed apparatus, one or more parameters to be used for the placeholder of the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the one or more parameters.

[0028] In a variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, the one or more parameters for the placeholder to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder.

[0029] In another variant, the placeholder may be configured for one or more lower layer parameters configured for the user equipment.

[0030] In another variant, the partial RRC configuration may be received from the central apparatus in separate RRC messages, the first configuration part being received in a first RRC message and the second configuration part being received in a second RRC message.

[0031] In another variant, the first configuration part and the second configuration part of the partial RRC configuration may be interleaved in a single RRC message received from the central apparatus.

[0032] In another variant, the partial RRC configuration may include an indication of one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

[0033] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder; receive, from the distributed apparatus with the one or more parameters, an identifier of the distributed apparatus; and update the second configuration part of the partial RRC configuration based on a determination that the identifier received from the distributed apparatus corresponds to the identifier received from the central apparatus.

[0034] In another variant, the user equipment may further caused to receive, from the distributed apparatus, one or more further parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more further parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the one or more further parameters.

[0035] In another variant, the user equipment may further be caused to receive, from a further distributed apparatus, one or more further parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more further parameters and the placeholder; transmit, to the further distributed apparatus, a message acknowledging receipt of the one or more further parameters.

[0036] In another variant, the second configuration part may include a further placeholder for the further distributed apparatus.

[0037] In another variant, the second configuration part may include a transaction identifier for tracing configuration signaling errors associated with the distributed apparatus.

[0038] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0039] In another variant, the user equipment may further be caused to indicate, to the central apparatus, whether the user equipment supports partial RRC configurations prior to receiving the partial RRC configuration.

[0040] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0041] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of a complete RRC configuration including the first configuration part and the second configuration part.

[0042] According to a fourth embodiment, a central apparatus of a network node is provided. The central apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the central apparatus at least to transmit, to a distributed apparatus of the network node, a request for configuring a partial radio resource control (RRC) configuration with at least a first configuration part and a second configuration part for a user equipment, the first configuration part being designated for a first set of parameters and the second configuration part being designated for a second set of parameters by a placeholder; receive, from the distributed apparatus, a response to the request for configuring the partial RRC configuration; determine the first set of parameters to be used for the first configuration part; and transmit, to the user equipment, the partial RRC configuration including the first set of parameters to be used for the first configuration part and the placeholder of the second configuration part.

[0043] In a variant, the request for configuring the partial RRC configuration may indicate at least an initial arrangement for the placeholder of the second configuration part.

[0044] In another variant, the request for configuring the partial RRC configuration may propose an arrangement for splitting the partial RRC configuration into the first configuration part and the second configuration part, and wherein the response to the request for configuring the partial RRC configuration includes an acknowledgement of the arrangement.

[0045] In another variant, the response to the request for configuring the partial RRC configuration may propose an arrangement for splitting for splitting the partial RRC configuration into the first configuration part and the second configuration part.

[0046] In another variant, the first set of parameters may be determined based on a subset of parameters indicated by the distributed apparatus.

[0047] In another variant, the central apparatus may further be caused to indicate, to the distributed apparatus, the first set of parameters to be used for the first configuration part.

[0048] In another variant, the first set of parameters may include upper layer parameters and the second set of parameters include lower layer parameters.

[0049] In another variant, the central apparatus may further be caused to transmit, to the distributed apparatus, one or more of an indication of the first set of parameters configured by the central apparatus for the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, an identifier associating the placeholder with the distributed apparatus, or an indication that the distributed apparatus should expect an acknowledgement from the user equipment.

[0050] In another variant, the central apparatus may further be caused to transmit, to the user equipment with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

[0051] In another variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, a parameter to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder.

[0052] In another variant, the partial RRC configuration may be transmitted to the user equipment in separate RRC messages, the first configuration part being transmitted in a first RRC message and the second configuration part being transmitted in a second RRC message.

[0053] In another variant, the first configuration part and the second configuration part of the partial RRC configuration may be interleaved in a single RRC message and transmitted to the user equipment.

[0054] In another variant, the placeholder may indicate one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

[0055] In another variant, the second configuration part may include a transaction identifier for tracing configuration signaling errors associated with the distributed apparatus.

[0056] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0057] In another variant, the central apparatus may further be caused to determine whether the user equipment supports partial RRC configurations prior to transmitting the partial RRC configuration.

[0058] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0059] In another variant, the central apparatus may further be caused to transmit, to the distributed apparatus, a query relating to the second configuration part.

[0060] In another variant, the central apparatus may further be caused to receive, from the distributed apparatus, an update relating to the second configuration part.

[0061] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of a complete RRC configuration including the first configuration part and the second configuration part.

[0062] According to a fifth embodiment, a distributed apparatus of a network node is provided. The distributed apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the distributed apparatus at least to receive, from a central apparatus of the network node, a request for configuring a partial radio resource control (RRC) configuration with at least a first configuration part and a second configuration part for a user equipment, the first configuration part being designated for a first set of parameters and the second configuration part being designated for a second set of parameters by a placeholder; transmit, to the central apparatus, a response to the request for configuring the partial RRC configuration; determine the second set of parameters to be used by the user equipment for the placeholder of the second configuration part; transmit, to the user equipment, the second set of parameters; and receive, from the user equipment, a message acknowledging receipt of the second set of parameters.

[0063] In a variant, the request for configuring the partial RRC configuration may indicate at least an initial arrangement for the placeholder of the second configuration part.

[0064] In another variant, the request for configuring the partial RRC configuration may propose an arrangement for splitting the partial RRC configuration into the first configuration part and the second configuration part, and wherein the response to the request for configuring the partial RRC configuration includes an acknowledgement of the arrangement.

[0065] In another variant, the response to the request for configuring the partial RRC configuration may propose an arrangement for splitting the partial RRC configuration into the first configuration part and the second configuration part.

[0066] In another variant, the distributed apparatus may further be caused to at least partially indicate, to the central apparatus, the first set of parameters to be used for the first configuration part.

[0067] In another variant, the distributed apparatus may further be caused to receive, from the central apparatus, an indication of the first set of parameters to be used for the first configuration part.

[0068] In another variant, the first set of parameters may include upper layer parameters and the second set of parameters include lower layer parameters.

[0069] In another variant, the second set of parameters may include parameters relating to one or more of measurement configurations or initial access for the user equipment.

[0070] In another variant, the distributed apparatus may further caused to receive, from the central apparatus, one or more of an indication of the first set of parameters configured by the central apparatus for the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, an identifier associating the placeholder with the distributed apparatus, or an indication that the distributed apparatus should expect an acknowledgement from the user equipment.

[0071] In another variant, the distributed apparatus may further caused to receive, from the user equipment, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0072] In another variant, the second set of parameters may be transmitted to the user equipment via medium access control (MAC) signaling.

[0073] In another variant, information relating to the placeholder may be provided in the MAC signaling.

[0074] In another variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, a parameter to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder.

[0075] In another variant, the placeholder may indicate one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

[0076] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0077] In another variant, the distributed apparatus may further be caused to receive, from the central apparatus, a query relating to the second configuration part.

[0078] In another variant, the distributed apparatus may further be caused to transmit, to the central apparatus, an update relating to the second configuration part.

[0079] In another variant, the distributed apparatus may further be caused to transmit, to the user equipment with the second set of parameters, an identifier of the distributed apparatus, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

[0080] In another variant, the distributed apparatus may further be caused to transmit, to the user equipment, a further set of parameters to be used for updating the second configuration part; and receive, from the user equipment, a message acknowledging receipt of the further set of parameters.

[0081] According to a sixth embodiment, a user equipment is provided. The user equipment may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment at least to receive, from a central apparatus of a network node, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part configured for a first set of parameters and a second configuration part configured for a second set of parameters, the second configuration part including a placeholder for the second set of parameters; receive, from a distributed apparatus of the network node, the second set of parameters to be used for the placeholder of the second configuration part; update the second configuration part of the partial RRC configuration based on the second set of parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the second set of parameters.

[0082] In a variant, the first set of parameters may include upper layer parameters and the second set of parameters include lower layer parameters.

[0083] In another variant, the second set of parameters may include parameters relating to one or more of measurement configurations or initial access for the user equipment.

[0084] In another variant, the second set of parameters may be received from the distributed apparatus via medium access control (MAC) signaling.

[0085] In another variant, information relating to the placeholder may be provided in the MAC signaling.

[0086] In another variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, a parameter to be provided by the distributedapparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder.

[0087] In another variant, the partial RRC configuration may be received from the central apparatus in separate RRC messages, the first configuration part being received in a first RRC message and the second configuration part being received in a second RRC message.

[0088] In another variant, the first configuration part and the second configuration part of the partial RRC configuration may be interleaved in a single RRC message received from the central apparatus.

[0089] In another variant, the placeholder may indicate one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

[0090] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder; receive, from the distributed apparatus with the second set of parameters, an identifier of the distributed apparatus; and update the second configuration part of the partial RRC configuration based on a determination that the identifier received from the distributed apparatus corresponds to the identifier received from the central apparatus.

[0091] In another variant, the user equipment may further be caused to receive, from the distributed apparatus, a further set of parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the further set of parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the one or more further parameters.

[0092] In another variant, the user equipment may further be caused to receive, from a further distributed apparatus, a further set of parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the further set of parameters and the placeholder; transmit, to the further distributed apparatus, a message acknowledging receipt of the further set of parameters.

[0093] In another variant, the second configuration part may include a further placeholder for the further distributed apparatus.

[0094] In another variant, the second configuration part may include a transaction identifier for tracing configuration signaling errors associated with the distributed apparatus.

[0095] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the distributed apparatus.

[0096] In another variant, the user equipment may further be caused to indicate, to the central apparatus, whether the user equipment supports partial RRC configurations prior to receiving the partial RRC configuration.

[0097] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0098] In another variant, the user equipment may further be caused to transmit, to the distributed apparatus, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0099] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of a complete RRC configuration including the first configuration part and the second configuration part.

[0100] In another variant, the user equipment may further be caused to apply the complete RRC configuration based on an indication received from the distributed apparatus

[0101] According to a seventh embodiment, a central apparatus of a network node is provided. The central apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the central apparatus at least to transmit, to a user equipment, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a central unit (CU) configuration part associated with the central apparatus and a distributed unit (DU) configuration part associated with one or more distributed apparatuses of the network node, the DU configuration part including a placeholder for the one or more distributed apparatuses; and transmit, to the one or more distributed apparatuses, information relating to the placeholder of the DU configuration part.

[0102] In a variant, the information relating to the placeholder may include one or more of an identifier of the placeholder, a size of the placeholder, a parameter for the placeholder to be provided by the one or more distributed apparatuses, a null element, a type definition, an identifier of the one or more distributed apparatuses, an indication of one or more parameters configured by the central apparatus to be transmitted to the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, or an indication that the one or more distributed apparatuses should expect an acknowledgement from the user equipment.

[0103] In another variant, the central apparatus may further be caused to transmit, to the user equipment with the partial RRC configuration, one or more identifiers of the one or more distributed apparatuses associated with the placeholder, the one or more identifiers enabling the user equipment to authenticate the one or more distributed apparatuses for the placeholder.

[0104] In another variant, each of the one or more identifiers may be associated with a unique distributed apparatus.

[0105] In another variant, a single identifier may be associated with the one or more distributed apparatuses.

[0106] In another variant, the placeholder may be configured for one or more lower layer parameters to be provided by the one or more distributed apparatuses.

[0107] In another variant, the partial RRC configuration may be transmitted to the user equipment in separate RRC messages, the CU configuration part being transmitted in a first RRC message and the DU configuration part being transmitted in a second RRC message.

[0108] In another variant, the CU configuration part and the DU configuration part of the partial RRC configuration may be interleaved in a single RRC message and transmitted to the user equipment.

[0109] In another variant, the information relating to the placeholder may indicate one or more configuration elements within the DU configuration part to be updated by the one or more distributed apparatuses.

[0110] In another variant, the DU configuration part may include a transaction identifier for tracing configuration signaling errors associated with the one or more distributed apparatuses, [oni] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the one or more distributed apparatuses.

[0112] In another variant, the central apparatus may further be caused to determine whether the user equipment supports partial RRC configurations prior to transmitting the partial RRC configuration.

[0113] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of the partial RRC configuration and the placeholder of the second configuration part.

[0114] In another variant, an arrangement for splitting the partial RRC configuration into the CU configuration part and the DU configuration part may be preconfigured.

[0115] In another variant, the central apparatus may further be caused to confirm, with the one or more distributed apparatuses, an arrangement for splitting the partial RRC configuration into the CU configuration part and the DU configuration part.

[0116] In another variant, the central apparatus may further be caused to transmit, to the one or more distributed apparatuses, a query relating to the DU configuration part.

[0117] In another variant, the central apparatus may further be caused to receive, from the one or more distributed apparatuses, an update relating to the DU configuration part.

[0118] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of a complete RRC configuration including the CU configuration part and the DU configuration part.

[0119] According to an eighth embodiment, a user equipment is provided. The user equipment may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment at least to receive, from a central apparatus of a network node, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a central unit (CU) configuration part associated with the central apparatus and a distributed unit (DU) configuration part associated with one or more distributed apparatuses of the network node, the DU configuration part including a placeholder for the one or more distributed apparatuses; receive, from a first distributed apparatus, a first set of parameters to be used for the DU configuration part; update the DU configuration part of the partial RRC configuration based on the first set of parameters and the placeholder; and transmit, to the first distributed apparatus, a message acknowledging receipt of the first set of parameters.

[0120] In a variant, the user equipment may further be caused to generate a complete RRC configuration based on the CU configuration part provided by the central apparatus and the DU configuration part provided by the one or more distributed apparatuses.

[0121] In another variant, the user equipment may further be caused to apply the complete RRC configuration based on an indication received from the one or more distributed apparatuses.

[0122] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, an identifier the first distributed apparatus associated with the placeholder; receive, from the first distributed apparatus with the first set of parameters, an identifier of the first distributed apparatus; and update the DUconfiguration part of the partial RRC configuration based on a determination that the identifier received from the first distributed apparatus corresponds to the identifier received from the central apparatus.

[0123] In another variant, the user equipment may further be caused to perform a cell change from a first cell associated with the first distributed apparatus to a second cell associated with a second distributed apparatus of the network node; receive, from the second distributed apparatus, a second set of parameters to be used for the DU configuration part; update the DU configuration part of the partial RRC configuration based on the second set of parameters and the placeholder; and transmit, to the second distributed apparatus, a message acknowledging receipt of the second set of parameters.

[0124] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, an identifier of the second distributed apparatus associated with the placeholder; receive, from the second distributed apparatus with the second set of parameters, an identifier of the second distributed apparatus; and update the DU configuration part of the partial RRC configuration based on a determination that the identifier received from the second distributed apparatus corresponds to the identifier received from the central apparatus.

[0125] In another variant, the placeholder may be indicated using one or more of an identifier of the placeholder, a size of the placeholder, one or more parameters for the placeholder to be provided by the one or more distributed apparatuses, a null element, a type definition, or an identifier of the one or more distributed apparatuses associated with the placeholder.

[0126] In another variant, the placeholder may be configured for one or more lower layer parameters configured for the user equipment.

[0127] In another variant, the partial RRC configuration may be received from the central apparatus in separate RRC messages, the CU configuration part being received in a first RRC message and the DU configuration part being received in a second RRC message.

[0128] In another variant, the CU configuration part and the DU configuration part of the partial RRC configuration may be interleaved in a single RRC message received from the central apparatus.

[0129] In another variant, the information relating to the placeholder may indicate one or more configuration elements within the DU configuration part to be updated by the one or more distributed apparatuses.

[0130] In another variant, the DU configuration part may include a transaction identifier for tracing configuration signaling errors associated with the one or more distributed apparatuses.

[0131] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus or the one or more distributed apparatuses.

[0132] In another variant, the user equipment may further be caused to indicate, to the central apparatus, whether the user equipment supports partial RRC configurations prior to receiving the partial RRC configuration.

[0133] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of the partial RRC configuration and the placeholder of the DU configuration part.

[0134] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of a complete RRC configuration including the CU configuration part and the DU configuration part.

[0135] According to a ninth embodiment, a central apparatus of a network node is provided. The central apparatus may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the central apparatus at least to transmit, to a user equipment, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a central unit (CU) configuration part associated with the central apparatus, a first distributed unit (DU) configuration part associated with a first distributed apparatus of the network node, and a second DU configuration part associated with a second distributed apparatus of the network node, the first DU configuration part including a first placeholder for the first distributed apparatus, and the second DU configuration part including a second placeholder for the second distributed apparatus; transmit, to the first distributed apparatus, information relating to the first placeholder of the first DU configuration part; and transmit, to the second distributed apparatus, information relating to the second placeholder of the second DU configuration part.

[0136] In a variant, the information relating to each of the first placeholder and the second placeholder may include one or more of an identifier of the respective placeholder, a size of the respective placeholder, a parameter for the respective placeholder to be provided by the respective distributed apparatus, a null element, a type definition, an identifier of the respective distributed apparatus, an indication of one or more parameters configured by the centralapparatus to be transmitted to the user equipment, an acknowledgement that the respective placeholder has been configured for the user equipment, or an indication that the respective distributed apparatus should expect an acknowledgement from the user equipment.

[0137] In another variant, the central apparatus may further be caused to transmit, to the user equipment with the partial RRC configuration, a first identifier of the first distributed apparatus associated with the first placeholder and a second identifier of the second distributed apparatus associated with the second placeholder, the first identifier enabling the user equipment to authenticate the first distributed apparatus for the first placeholder, and the second identifier enabling the user equipment to authenticate the second distributed apparatus for the second placeholder.

[0138] In another variant, each of the first placeholder and the second placeholder may be configured for a respective set of lower layer parameters to be provided by the respective distributed apparatus.

[0139] In another variant, the partial RRC configuration may be transmitted to the user equipment in separate RRC messages, the CU configuration part being transmitted in a first RRC message, the first DU configuration part being transmitted in a second RRC message, and the second DU configuration part being transmitted in a third RRC message.

[0140] In another variant, the CU configuration part, the first DU configuration part, and the second DU configuration part of the partial RRC configuration may be interleaved in a single RRC message and transmitted to the user equipment.

[0141] In another variant, the CU configuration part and the first DU configuration part may be transmitted to the user equipment in a single RRC message, and the second DU configuration part of the partial RRC configuration may be transmitted to the user equipment in a separate RRC message.

[0142] In another variant, the information relating to the each of the first placeholder and the second placeholder may indicate a respective set of configuration elements within the respective DU configuration part to be updated by the respective distributed apparatus.

[0143] In another variant, each of the first DU configuration part and the second DU configuration part may include a respective transaction identifier for tracing configuration signaling errors associated with the respective distributed apparatus.

[0144] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus, the first distributed apparatus, or the second distributed apparatus.

[0145] In another variant, the central apparatus may further be caused to determine whether the user equipment supports partial RRC configurations prior to transmitting the partial RRC configuration.

[0146] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of the partial RRC configuration, the first placeholder of the first DU configuration part, and the second placeholder of the second DU configuration part.

[0147] In another variant, an arrangement for splitting the partial RRC configuration into the CU configuration part, the first DU configuration part, and the second DU configuration part may be preconfigured.

[0148] In another variant, the central apparatus may further be caused to confirm, with the first distributed apparatus and the second distributed apparatus, an arrangement for splitting the partial RRC configuration into the CU configuration part, the first DU configuration part, and the second DU configuration part.

[0149] In another variant, the central apparatus may further be caused to at least one of transmit, to the first distributed apparatus, a query relating to the first DU configuration part; or transmit, to the second distributed apparatus, a query relating to the second DU configuration.

[0150] In another variant, the central apparatus may further be caused to at least one of receive, from the first distributed apparatus, an update relating to the first DU configuration part; or receive, from the second distributed apparatus, an update relating to the second DU configuration part.

[0151] In another variant, the central apparatus may further be caused to receive, from the user equipment, a message acknowledging receipt of a complete RRC configuration including the CU configuration part and one of the first DU configuration part or the second DU configuration part

[0152] According to a tenth embodiment, a user equipment is provided. The user equipment may include at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment at least to receive, from a central apparatus of a network node, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a central unit (CU) configuration part associated with the central apparatus, a first distributed unit (DU) configuration part associated with a firstdistributed apparatus of the network node, and a second DU configuration part associated with a second distributed apparatus of the network node, the first DU configuration part including a first placeholder for the first distributed apparatus, and the second DU configuration part including a second placeholder for the second distributed apparatus; receive, from the first distributed apparatus, a first set of parameters to be used for the first DU configuration part; update the first DU configuration part of the partial RRC configuration based on the first set of parameters and the first placeholder; and transmit, to the first distributed apparatus, a message acknowledging receipt of the first set of parameters.

[0153] In a variant, the user equipment may further be caused to generate a complete RRC configuration based on the CU configuration part provided by the central apparatus and the first DU configuration part provided by the first distributed apparatus.

[0154] In another variant, the user equipment may further be caused to apply the complete RRC configuration based on an indication received from the first distributed apparatus.

[0155] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, a first identifier of the first distributed apparatus associated with the first placeholder; receive, from the first distributed apparatus with the first set of parameters, an identifier of the first distributed apparatus; and update the first DU configuration part of the partial RRC configuration based on a determination that the identifier received from the first distributed apparatus corresponds to the first identifier received from the central apparatus.

[0156] In another variant, the user equipment may further be caused to perform a cell change from a first cell associated with the first distributed apparatus to a second cell associated with the second distributed apparatus; receive, from the second distributed apparatus, a second set of parameters to be used for the second DU configuration part; update the second DU configuration part of the partial RRC configuration based on the second set of parameters and the second placeholder; and transmit, to the second distributed apparatus, a message acknowledging receipt of the second set of parameters.

[0157] In another variant, the user equipment may further be caused to receive, from the central apparatus and with the partial RRC configuration, a second identifier of the second distributed apparatus associated with the second placeholder; receive, from the second distributed apparatus with the second set of parameters, an identifier of the second distributed apparatus; and update the second DU configuration part of the partial RRC configuration basedon a determination that the identifier received from the second distributed apparatus corresponds to the second identifier received from the central apparatus.

[0158] In another variant, each of the first placeholder and the second placeholder may be indicated using one or more of an identifier of the respective placeholder, a size of the respective placeholder, a parameter for the respective placeholder to be provided by the respective distributed apparatus, a null element, a type definition, or an identifier of the respective distributed apparatus.

[0159] In another variant, each of the first placeholder and the second placeholder may be configured for a respective set of lower layer parameters to be provided by the respective distributed apparatus.

[0160] In another variant, the partial RRC configuration may be received from the central apparatus in separate RRC messages, the CU configuration part being received in a first RRC message, the first DU configuration part being received in a second RRC message, and the second DU configuration part being received in a third RRC message.

[0161] In another variant, the CU configuration part, the first DU configuration part, and the third DU configuration part of the partial RRC configuration may be interleaved in a single RRC message received from the central apparatus.

[0162] In another variant, the CU configuration part and the first DU configuration part may be received from the central apparatus in a single RRC message, and the second DU configuration part of the partial RRC configuration may be received from the central apparatus in a separate RRC message.

[0163] In another variant, the information relating to each of the first placeholder and the second placeholder may indicate a respective set of configuration elements within the respective DU configuration part to be updated by the respective distributed apparatus.

[0164] In another variant, each of the first DU configuration part and the second configuration part may include a respective transaction identifier for tracing configuration signaling errors associated with the respective distributed apparatus.

[0165] In another variant, the partial RRC configuration may be associated with a version identifier identifying one or more of the central apparatus, the first distributed apparatus, or the second distributed apparatus.

[0166] In another variant, the user equipment may further be caused to indicate, to the central apparatus, whether the user equipment supports partial RRC configurations prior to receiving the partial RRC configuration.

[0167] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of the partial RRC configuration, the first placeholder of the first DU configuration part, and the second placeholder of the second DU configuration part.

[0168] In another variant, the user equipment may further be caused to transmit, to the central apparatus, a message acknowledging receipt of a complete RRC configuration including the CU configuration part and one of the first DU configuration part or the second DU configuration part.BRIEF DESCRIPTION OF THE DRAWINGS:

[0169] For proper understanding of example embodiments, reference should be made to the accompanying drawings, wherein:

[0170] Fig. 1 illustrates a schematic example of a system within a network environment;

[0171] Fig. 2 illustrates a schematic example of a split architecture of a network node;

[0172] Fig. 3 illustrates a diagram of an example lower layer triggered mobility (LTM) procedure;

[0173] Fig. 4 illustrates a schematic example of a radio resource control (RRC) configuration;

[0174] Fig. 5 illustrates a schematic of an example partial RRC configuration of the present disclosure;

[0175] Fig. 6 illustrates a schematic of an exemplary process for enabling distributed signaling according to the present disclosure;

[0176] Figs. 7A-7F illustrate example RRC information element (IE) definitions of the present disclosure;

[0177] Fig. 8 illustrates a diagram of an example embodiment of the present disclosure;

[0178] Fig. 9 illustrates a diagram of an example embodiment of the present disclosure;

[0179] Fig. 10 illustrates a diagram of an example embodiment of the present disclosure;

[0180] Fig. 11 illustrates a schematic of an example partial RRC configuration of the present disclosure;

[0181] Fig. 12 illustrates a schematic of an example partial RRC configuration of the present disclosure;

[0182] Fig. 13 illustrates a schematic of an example partial RRC configuration of the present disclosure;

[0183] Fig. 14 illustrates an example RRC IE definition of the present disclosure;

[0184] Fig. 15 illustrates a diagram of an example method of the present disclosure;

[0185] Fig. 16 illustrates a diagram of an example method of the present disclosure;

[0186] Fig. 17 illustrates a diagram of an example method of the present disclosure;

[0187] Fig. 18 illustrates a diagram of an example method of the present disclosure;

[0188] Fig. 19 illustrates a diagram of an example method of the present disclosure;

[0189] Fig. 20 illustrates a diagram of an example method of the present disclosure;

[0190] Fig. 21 illustrates a diagram of an example method of the present disclosure;

[0191] Fig. 22 illustrates a diagram of an example method of the present disclosure;

[0192] Fig. 23 illustrates a diagram of an example method of the present disclosure;

[0193] Fig. 24 illustrates a diagram of an example method of the present disclosure;

[0194] Fig. 25 illustrates a schematic block diagram of an example apparatus according to aspects of the present disclosure; and

[0195] Fig. 26 illustrates schematic examples of (tangible and / or non-transitory) computer- readable storage media.DETAILED DESCRIPTION:

[0196] It will be readily understood that the components of certain example embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of some example embodiments of systems, methods, apparatuses, and computer program products for sensing and localization enhancements is not intended to limit the scope of certain embodiments but is representative of selected example embodiments.

[0197] The features, structures, or characteristics of example embodiments described throughout this specification may be combined in any suitable manner in one or more example embodiments. For example, the usage of the phrases “certain embodiments,” “some embodiments,” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Thus, appearances of the phrases “in certain embodiments,” “in some embodiments,” “in other embodiments,” or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. In addition, the phrase “set of’ refers to a set that includes one or more of the referenced set members. As such, the phrases “set of,” “one ormore of,” and “at least one of,” or equivalent phrases, may be used interchangeably. Further, “or” is intended to mean “and / or,” unless explicitly stated otherwise.

[0198] Additionally, if desired, the different functions or operations discussed below may be performed in a different order and / or concurrently with each other. Furthermore, if desired, one or more of the described functions or operations may be optional or may be combined. As such, the following description should be considered as merely illustrative of the principles and teachings of certain example embodiments, and not in limitation thereof.

[0199] Example embodiments described may be implemented in a radio system. Some examples of a suitable communication networks include a 5G network and / or a 6G network. The 3rd Generation Partnership Project (3GPP) solution to 5G is referred to as New Radio (NR). 6G is envisaged to be a further development of 5G. NR has been envisaged to use multiple-input-multiple-output (MIMO) multi-antenna transmission techniques, more base stations or nodes than the current network deployments of LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller local area access nodes and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates. 5G will likely be comprised of more than one radio access technology / radio access network (RAT / RAN), each optimized for certain use cases and / or spectrum. 5G mobile communications may have a wider range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications, including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and being integrable with existing legacy radio access technologies, such as the LTE.

[0200] The current architecture in LTE networks is distributed in the radio and centralized in the core network. The low latency applications and services in 5G may require bringing the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach may require leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. Edge computing provides a distributed computing environment for application and service hosting. Edge computing also has the ability to store and process content in close proximity to cellular subscribers for faster response time.

[0201] Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud / fog computing and grid / mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications). Edge cloud may be brought into RAN by utilizing network function virtualization (NVF) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. Network slicing allows multiple virtual networks to be created on top of a common shared physical infrastructure. The virtual networks are then customized to meet the specific needs of applications, services, devices, customers, or operators.

[0202] Fig. 1 discloses a schematic of an example system 100 within a network environment illustrating a handover. As shown, the system 100 may generally include a network node 102 and a user equipment (UE) 104. The network node 102 may represent a base station, a TRP, and / or another access point, network entity, and / or the like. The UE 104 may represent a terminal, a user device, a mobile device, a mobile unit, an Internet of Things (loT) device, a smart device, and / or the like. The network node 102 may provide a (current) serving cell 106 and a (candidate) target cell 108 to the UE 104. When the UE 104 moves 110 and transmits measurement reports (e.g. on the serving cell 106 and the target cell 108), the network node 102 may send an indication of a handover configuration for a handover of the UE 104 to the target cell 108. Subsequently, the UE 104 may perform a handover to the target cell 108.

[0203] Although shown with only one network node 102 and only one UE 104, it will be understood that the system 100 may include a plurality of network nodes 102 and / or a plurality of UEs 104. A plurality of network nodes 102 (e.g., gNBs) may be connected to or in communication with each other via an Xn interface over which the network nodes 102 may negotiate. The network nodes 102 may also be connected over next generation (NG) interfaces to a 5G core network (5GC), which may be a 5G equivalent for the core network of LTE. In some applications, the network node 102 (e.g., gNB) may be implemented in a split architecture, each network node 102 having at least one central unit (CU) or central apparatus and one or more distributed units (DUs) or distributed apparatuses.

[0204] Fig. 2 discloses a schematic illustration of a split architecture 200 of a network node 102. As shown, a network node 102 (e.g., a gNB) may be split into a central apparatus 202(e.g., gNB-CU acting as server or host of the gNB) and a plurality of distributed apparatuses 204 (e.g., gNB-DUs acting as radio heads of the gNB). The central apparatus 202 may at least partly control a plurality of spatially separated distributed apparatuses 204 acting at least as transmit / receive (Tx / Rx) nodes for the network node 102. The central apparatus 202 may further be split into a control plane part 202-1 (e.g., gNB-CU-CP) and a user plane part 202-2 (e.g., gNB-CU-UP). The central apparatus 202 may communicate with the distributed apparatuses 204 via an Fl interface (e.g., Fl-C for control plane exchanges and Fl-U for user plane exchanges). The control plane part 202-1 of the central apparatus 202 may further communicate with the user plane part 202-2 of the central apparatus 202 via an El interface. Network node operations may be carried out at least partly in the central apparatus 202 or distributed among a plurality of central apparatuses 202. The distribution of work between core network operations and base station operations may vary depending on implementation.

[0205] The central apparatus 202 may comprise or host higher or upper protocol layers, such as a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and an internet protocol (IP) layer. The distributed apparatus 204 may comprise or host lower protocol layers, such as a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. Such 5G CU-DU split architecture may be implemented using cloud / server so that the central apparatus 202 handling upper layers is disposed in a cloud and the distributed apparatuses 204 handling lower layers are closer to or comprise actual radio and antenna units. Further, a single distributed apparatus 204 may be configured to host a plurality of cells. Such split architectures can be particularly beneficial in dense networks.

[0206] Referring back to Fig. 1, a handover from a serving cell to a candidate or target cell can be performed in a number of different ways. Until recently (e.g., until Release 17 3GPP standards), all types of handovers were triggered by layer 3 (L3) measurements and executed via RRC signaling (e.g., reconfiguration and synchronization). Such handovers involved reconfiguration of higher or upper layers (e.g., RRC or PDCP) and / or resetting of lower layers (e.g., MAC and / or PHY) which led to longer latency, larger overhead, and longer interruption times than beam level mobility. More recent developments (e.g., Release 18 3GPP standards) have introduced layer 1 (Ll) / layer 2 (L2) based mobility also known as lower layer triggered mobility (LTM) to enable a serving cell change via L1 / L2 signaling. With LTM, it may be possible to maintain the configurations of the upper layers and / or minimize reconfigurationsof the lower layers. LTM thereby aids in reducing latency, overhead, and / or interruption time associated with handovers.

[0207] Fig. 3 discloses a diagram of an example LTM procedure 300. As shown, the LTM procedure 300 is generally comprised of four phases including a preparation phase 302, an early synchronization phase 304, an execution phase 306, and a completion phase 308. During the preparation phase 302, a central apparatus 202 of a serving cell (e.g., serving CU) identifies candidate target cells based on L3 measurement reports, prepares the target cells, and shares the target cell configurations with the UE 104. During the early synchronization phase 304, the distributed apparatus 204 of the serving cell (e.g., serving DU) asks (considering LI measurements) the UE 104 to perform timing advance (TA) acquisition for a specific target cell. During the execution phase 306, the distributed apparatus 204-1 of the serving cell (e.g., serving DU) decides (considering LI measurements) on the target cell and asks the UE 104 to switch to the target cell, and the UE 104 switches to the target cell. During the completion phase 308, UE context may be released from the other unselected cells. In some cases, the UE context may be maintained by the other unselected cells for a period of time as determined by the central apparatus 202. In cases where the UE 104 maintains the configurations of the target cell, the UE 104 may perform multiple / subsequent LTM operations (e.g., subsequent LTM).

[0208] Fig. 4 discloses a schematic example of a RRC configuration (or reconfiguration) 400 in a CU-DU split architecture. The RRC configuration 400 may be needed for configuring a UE 104 for a L3 handover, for configuring a UE 104 for a LTM procedure 300, or for configuring a UE 104 for new measurement reports, etc. As shown in Fig. 4 and with further reference to Fig. 3, the distributed apparatus 204 may be responsible for configuring the lower layer parameters for the UE 104. If the central apparatus 202 decides to configure LTM (e.g., Step 3 of Fig. 3), the central apparatus 202 may request the lower layer parameters from the distributed apparatus 204 (e.g., Steps 4-7 of Fig. 3). In turn, the central apparatus 202 may pack the lower layer parameters provided by the distributed apparatus 204 together with upper layer parameters or configurations in a RRC reconfiguration message (e.g., Step 8 of Fig. 3) to be transmitted in downlink (DL) to the UE 104 via the distributed apparatus 204 (e.g., Steps 9- 10 of Fig. 3).

[0209] In 6G, dense networks may be highly likely or common. In a dense network, each central unit (e.g., central apparatus 202) may manage several distributed units (e.g., distributed apparatuses 204), and each distributed unit may host several cells. Given such a dense network, the number of possible handovers needed could be quite significant, for instance, between cellsof a single distributed unit, between cells across different distributed units, and / or between cells across different distributed units managed by different central units. Since a central unit needs to receive lower layer parameters from the distributed unit and compile RRC configurations for each handover, a central unit in a dense network may be subject to extra processing loads and extra traffic therethrough. Also since configuration elements created at the distributed unit need to travel through the central unit for each handover, this can cause extra delays for user equipment awaiting to receive the necessary lower layer configurations.

[0210] Accordingly, given these observations, there is a need for a solution that can sufficiently support dense networks while reducing unnecessary burdens on the network and / or user equipment. The present disclosure presents such solutions. In particular, the present disclosure provides solutions which enable one or more portions of a RRC configuration or reconfiguration to be essentially set aside and designated for a distributed unit (e.g., distributed apparatus 204). The designated portions of the RRC configuration or reconfiguration can be updated by a respective distributed unit separately or with reduced involvement by a central unit managing the distributed unit. In this way, solutions provided by the present disclosure enable distributed configuration signaling that can help reduce unnecessary exchanges or signaling between the central unit and either of the distributed units or user equipment, thereby reducing processing loads of the central unit, reducing traffic passing through the central unit, as well as reducing delays to the user equipment or network.

[0211] Fig. 5 discloses a schematic of an exemplary embodiment 500 of the present disclosure for generating a RRC configuration (or reconfiguration) with distributed signaling as compared with a legacy approach 400 (also as shown in Fig. 4) for generating a RRC configuration. As shown, according to the legacy approach 400, a central apparatus 202 generates upper layer parameters (C l) for a UE 104, and a distributed apparatus 204 generates lower layer parameters (C_2) for the UE 104. The central apparatus 202 then receives the lower layer parameters (C_2) from the distributed apparatus 204, and merges the upper layer parameters (C l) with the lower layer parameters (C_2) to generate the complete RRC configuration (C) for the UE 104. The central apparatus 202 then transmits the complete RRC configuration (C) to the UE 104. In the legacy approach 400, all signaling with respect to the RRC configuration for the UE 104 are passed through the central apparatus 202, thereby introducing more processing load and more traffic through the central apparatus 202 and adding more communication delays overall.

[0212] In contrast, in the embodiment 500 of Fig. 5, distributed signaling is used. For instance, the RRC configuration (C) is split into different portions, sections, or parts, and the signaling for the respective parts of the RRC configuration is distributed amongst the central apparatus 202 and the distributed apparatus 204. More specifically, the central apparatus 202 generates and transmits to the UE 104 a partial RRC configuration (C_lp) with the upper layer parameters, and the distributed apparatus 204 generates and transmits to the UE 104 the lower layer parameters (C_2). The UE 104 can then merge, compile, update, and / or otherwise use the parts to generate the complete RRC configuration (C). In some examples, as will be discussed in more detail below, the UE 104 may merge or update the partial RRC configuration (C_lp) with the lower layer parameters (C_2). In other examples, it may be possible to merge or update the lower layer parameters (C_2) with the upper layer parameters of the partial RRC configuration (C_lp) in order to generate the complete RRC configuration (C). Such distributed signaling aids to offload some of the extra processing load and extra traffic through the central apparatus 202 onto the distributed apparatus 204, which may be nearer to the UE 104 or otherwise more suited to provide at least the lower layer parameters (C_2).

[0213] Fig. 6 discloses a schematic of an exemplary process 600 by which a RRC configuration can be split into parts, and by which the parts can be merged, compiled, or updated in order to generate or reconstruct the complete RRC configuration. As shown, such a partial RRC configuration can be split into a first configuration part 602 and a second configuration part 604. Although referred to as a partial RRC configuration herein, the partial RRC configuration may also be referred to as a split RRC configuration, a distributed RRC configuration, a divided RRC configuration, a placeholder RRC configuration, and / or the like. As will be discussed in more detail further below, the structure and / or contents of the partial RRC configuration or the arrangement of the split may be predefined, initially negotiated, and / or otherwise agreed upon between a central apparatus 202 (Block Al) and a distributed apparatus 204 (Block Bl). As also will be discussed further below, a partial RRC configuration can further be split into more than two parts in some cases.

[0214] Based on the agreed split, the central apparatus 202 (Block A2) may prepare the partial RRC configuration (C_lp) having the first configuration part 602 and the second configuration part 604. The first configuration part 602 may include actual values or upper layer parameters that have been configured for a UE 104. The second configuration part 604 may not include actual values, but rather a placeholder 606 used to designate a portion (e.g., the second configuration part 604) of the partial RRC configuration to be updated by the distributedapparatus 204. In some examples, the placeholder 606 is provided with an identifier of the distributed apparatus 204 that the UE 104 can use to verify or authenticate the distributed apparatus 204 for the second configuration part 604. As will be discussed in more detail further below, the placeholder 606 may be provided in different forms, but at a minimum, includes information enabling the UE 104 to complete the RRC configuration (C). In one embodiment, the central apparatus 202 may generate a list of identifiers (e.g., one-time-use identifiers, tokens, and / or the like) and send the list of identifiers to both the distributed apparatus 204 and the UE 104. This may happen prior to sending the partial RRC configuration (C_lp) and the lower layer parameters (C_2). The identifier which may be included in the placeholder 606 may be taken from the mentioned list of identifiers (e.g., in a descending or top-to-bottom list order).

[0215] Once the partial RRC configuration (C_lp) is prepared, the central unit 202 (Block A3) may transmit, and the UE 104 (Block Cl) may receive, the first configuration part 602 and the second configuration part 604 with the placeholder 606. The distributed apparatus 204 (Block B2) may wait for a confirmation from the UE 104 and / or the central apparatus 202 acknowledging that the UE 104 is configured with the placeholder 606 and ready to receive lower layer parameters (C_2) from the distributed apparatus 204. Accordingly, the distributed apparatus 204 (Block B3) may prepare the lower layer parameters (C_2) e.g., actual values or configuration elements associated therewith to be used for the second configuration part 604. Once the lower layer parameters are prepared, the distributed unit 204 (Block B4) may transmit, and the UE 104 (Block C2) may receive, the lower layer parameters (C_2). The UE 104 (Block C3) may then form the complete RRC configuration (C) by merging or filling in the lower layer parameters (C_2) into the second configuration part 604 of the partial RRC configuration (C_lp) as indicated by the placeholder 606.

[0216] In some embodiments, the second configuration part 604 may comprise an identifier. The identifier may be taken from the aforementioned list of identifiers. If the identifier of the second configuration part 604 matches or corresponds to one of those indicated in the list of identifiers, the UE 104 may then merge the first configuration part 602 and the second configuration part 604. In some instances, for example, if the identifier is taken from a list of one-time-use identifiers, the identifier may be removed from the list. In some examples, if the list of identifiers is indexed in a descending or top-to-bottom list order, the matching or used identifier as well as any preceding identifiers in the list of identifiers may also be removed fromthe list. In some examples, an internal pointer of the distributed apparatus 204 may simply be updated to point to the next entry or identifier within the list of identifiers.

[0217] In some examples, if subsequent updates to the lower layer parameters (C_2) are needed, the distributed apparatus 204 (Block B5) may transmit, and the UE 104 (Block C4) may receive, updated lower layer parameters (C_2_u) for the UE 104. The UE 104 (Block C5) may update or generate the complete RRC configuration (C_u) by merging or filling in the updated lower layer parameters (C_2_u) into the second configuration part 604 of the partial RRC configuration (C_lp) indicated by the same placeholder 606. Furthermore, a RRC version number or identifier associated with the RRC configuration (C) may be provided to the UE 104, e.g., along with the partial RRC configurations (C_lp) and / or the placeholder 606, which may be used by the UE 104 to associate the RRC configuration (C) with the central apparatus 202 and / or the distributed apparatus 204. Using the RRC version number or identifier, the UE 104 may be able to apply updated lower layer parameters (C_2_u) without involving the central apparatus 202 or additional RRC signaling therewith. In some further examples, a given set of the lower layer parameters (C_2) may be similarly refreshed using the same placeholder 606, but with updated lower layer parameters (C_2_u) from a different distributed apparatus 204 that may be managed by the same central apparatus 202.

[0218] Although Fig. 6 depicts a RRC configuration that is split into two configuration parts, a first configuration part 602 for a central apparatus 202 and a second configuration part 604 for a distributed apparatus 204, it will be understood that other arrangements or extensions are possible. For example, in some embodiments, a RRC configuration may be split into three or more configuration parts, a first configuration part 602 for a central apparatus 202 and two or more configuration parts 604 for two or more distributed apparatuses 204 that may be managed by the same central apparatus 202. In such examples, partial RRC configurations may include two or more placeholders 606 for designating respective portions or configuration parts 604 of the RRC configuration for the two or more distributed apparatuses 204. In still further examples, a single configuration part 604 of a RRC configuration may be reused or updated by two or more distributed apparatuses 204 that may be managed by the same central apparatus 202. For instance, the same placeholder 606 for a given configuration part 604, but used by more than one distributed apparatus 204.

[0219] Figs. 7A-7F disclose example definitions, e.g., RRC information element (IE) definitions, that can be used to implement placeholders 606 and a second configuration part 604 of a partial RRC configuration. In one example, as shown in Fig. 7A, the placeholder 606may be implemented as a NULL element. In the example shown, a central apparatus 202 may choose to send to a UE 104 the NULL element in the second configuration part 604 rather than actual values (e.g., MeasConfig) to indicate to the UE 104 that the actual values or lower layer parameters will be provided later by a distributed apparatus 204. The actual values or lower layer values may then be provided by the distributed apparatus 204 as a MAC message defined with values cast into a byte array in a conventional manner, and / or the like.

[0220] In another example, as shown in Fig. 7B, the placeholder 606 may be implemented via a type definition (e.g., ValuePlaceholder) using a referenced data type (e.g., ElementTypeParam) for the lower layer parameters (e.g., MeasConfig). For instance, the central apparatus 202 may choose to send the placeholder 606 to the UE 104 by referencing the type definition to the NULL element. In the example shown, the central apparatus 202 may set measConfig as either “placeholder” defined as a NULL element or “value” defined as MeasConfig. If measConfig was set to “placeholder,” then the UE 104 may wait for the distributed apparatus 204 to provide the actual values or lower layer parameters for measConfig. If measConfig is set to “value,” the UE 104 may use the actual values or lower layer parameters provided for measConfig.

[0221] In another example, as shown in Fig. 7C, the placeholder 606 may be implemented within related messages. For instance, the RRC IE definitions shown reflect when the central apparatus 202 and the distributed apparatus 204 have already agreed to use measConfg and csi- MeasConfig as placeholders 606. In this example, if the central apparatus 202 and the distributed apparatus 204 have agreed that only c i-measConfig will be provided by the distributed apparatus 204, then the central apparatus 202 may send only the c i-measConfig in a RRC message to the UE 104 to indicate the placeholder 606 to be filled in by the distributed apparatus 204 later.

[0222] In another example, as shown in Fig. 7D, the placeholder 606 may be provided with one or more identifiers (e.g., measConfigP laceholder ID). The identifier may be identifying the distributed apparatus 204 associated with the placeholder 606. The identifier may be one of a list of one-time-use identifiers that the central apparatus 202 provided to the distributed apparatus 204 as well as the UE 104, such that the UE 104 knows that the placeholder 606 or placeholder message is valid. The central apparatus 202 may send the identifiers to the UE 104 in a RRC message to specify the specific distributed apparatus 204 the UE 104 should receive the lower layer parameters from. The distributed apparatus 204 may send its respective identifier along with the lower layer parameters to the UE 104 in a MAC message format. TheUE 104 may update the second configuration part 604 with the lower layer parameters provided by the distributed apparatus 204, but only if the identifier provided by the distributed apparatus 204 matches or corresponds to the identifier provided by the central apparatus 202. Use of such identifiers may help the UE 104 to verify or authenticate a distributed apparatus 204 before accepting the values or parameters provided by the distributed apparatus 204. In the example shown, each identifier may be unique to each placeholder 606 and / or each distributed apparatus 204. In some other examples, it may be possible to have an identifier that is associated with multiple placeholders 606 and / or multiple distributed apparatuses 204.

[0223] In a related example, as shown in Fig. 7E, the placeholder 606 may be provided with one or more identifiers (e.g., measConfigPlaceholderlD as in the example shown in Fig. 7D, but the identifiers may be provided via a type definition similar to the example shown in Fig. 7B. More specifically, the identifiers may be indicated via a type definition (e.g., ValuePlaceholde ) using a referenced data type (e.g., ElementTypeParam) for the lower layer parameters (e.g., MeasConfig). For instance, the central apparatus 202 may choose to indicate the identifier to the UE 104 by referencing the type definition to a list of identifiers (e.g., MeasConfigPlaceholderlDLisf), and the list may include the identifier (e.g., measConfigPlaceholderlD) of the authorized distributed apparatus 204 as in the example of Fig. 7D.

[0224] In another example, as shown in Fig. 7F, the placeholder 606 may be implemented within related messages when the central apparatus 202 and the distributed apparatus 204 have already agreed upon what each entity will send to the UE 104. In the example shown, the central apparatus 202 may have agreed to provide the UE 104 with a RRC message with MeasConfig with placeholders 606 for the second configuration part 604, and the distributed apparatus 204 may have agreed to provide the UE 104 with configuration elements measObj and reportConfig to be used to fill in the placeholder 606.

[0225] Fig. 8 discloses a diagram of one example embodiment 800 of distributed signaling according to the present disclosure. As shown, the distributed signaling may involve a UE 104, a central apparatus 202 of a serving cell (e.g., Serving CU), and a distributed apparatus 204 (e.g., Serving DU1, DUECelll, DUl :Cell2) that may be associated with the serving cell and one or more other candidate cells. The distributed apparatus 204 may be managed by the central apparatus 202 using a CU-DU split architecture as noted above, and communicate directly with the UE 104 via a distributed signaling. Although Fig. 8 depicts a single distributed apparatus 204, it will be understood that the central apparatus 202 may manage additionaldistributed apparatuses 204 across one or more additional cells. As will be discussed in more detail further below, the distributed signaling of the present disclosure could further be extended to additional distributed apparatuses 204.

[0226] At 800-0 of Fig. 8, initial access may be performed, during which the UE 104 may acquire a full RRC configuration (e.g., PDCP, RLC, MAC, and PHY layer parameters) of a given serving cell from the network via the serving central apparatus 202 and / or the serving distributed apparatus 204. At 800-1, the UE 104 may be connected to the serving cell and have a RRC connection with the central apparatus 202. While the UE 104 is in a RRC Connected state, the central apparatus 202 at 800-2 may optionally perform a check to determine whether the UE 104 supports a partial RRC configuration as shown for example in Fig. 6. In other embodiments, the central apparatus 202 may not need to perform the check at 800-2, for instance, if the UE 104 is already known to support partial RRC configurations (e.g., based on a prior session or exchange with the UE 104, based on a pre-configuration of the UE 104, or otherwise).

[0227] If the central apparatus 202 determines that the UE 104 does not support partial RRC configurations, the central apparatus 202 and the distributed apparatus 204 may proceed according to conventional RRC configurations. If, however, the central apparatus 202 determines that the UE 104 supports partial RRC configurations, the central apparatus 202 may proceed to negotiate with the distributed apparatus 204 on an arrangement for the partial RRC configuration. The negotiations may relate to an arrangement for splitting the partial RRC configuration into a first configuration part 602 and a second configuration part 604, an arrangement for the placeholder 606 of the second configuration part 604, and / or the like. In some examples, the negotiations may be triggered by a positive result of the check performed at 800-2, e.g., if the UE 104 is found to support partial RRC configurations. In other examples, negotiations may be triggered automatically e.g., by the UE 104 entering the cell served by the central apparatus 202, and / or by another condition.

[0228] To determine the arrangement for the partial RRC configuration, the central apparatus 202 at 800-3 of Fig. 8 may transmit to the distributed apparatus 204 a request for configuring the partial RRC configuration, and the distributed apparatus 204 at 800-4 may transmit a response to the request. In one example, the central apparatus 202 at 800-3 may propose an arrangement for splitting the partial RRC configuration into the first configuration part 602 and the second configuration part and / or an arrangement for the placeholder 606 of the second configuration part 604. In turn, the distributed apparatus 204 at 800-4 may respond with anacknowledgement of the proposed arrangement for splitting the partial RRC configuration and / or the arrangement for the placeholder 606. In another example, the central apparatus 202 at 800-3 may not include a proposed arrangement, but rather allow the distributed apparatus 204 to propose or decide on the arrangement for splitting the partial RRC configuration and / or the arrangement for the placeholder 606. In turn, the distributed apparatus 204 at 800-4 may respond with an arrangement for splitting the partial RRC configuration and / or an arrangement for the placeholder 606 for the central apparatus 202 to use.

[0229] In either example, a response by either the central apparatus 202 or the distributed apparatus 204 may finalize the arrangement for splitting the partial RRC configuration and / or the arrangement for the placeholder 606. In other embodiments, further signaling between the central apparatus 202 and the distributed apparatus 204 may be needed if a proposed arrangement is not agreed upon or needs modification by either entity. In still some other embodiments not shown here, it may be possible for the distributed apparatus 204 to transmit to the central apparatus 202 the request for configuring the partial RRC configuration, and for the central apparatus 202 to transmit a response to the request. While the arrangement or structure of partial RRC configuration may be negotiated in a number of different ways, the outcome should be at least an agreement between the central apparatus 202 and the distributed apparatus 204 of the respective parameters to be provided by the respective entities. The respective parameters may be indicated with parameter names or other identifiers and need not include actual parameter values.

[0230] At 800-5 of Fig. 8, the distributed apparatus 204 may transmit to the central apparatus 202 one or more parameters to be used by the UE 104. For instance, the one or more parameters may include only upper layer parameters that will be needed by the central apparatus 202 for RRC signaling and exclude lower layer parameters that will be provided to the UE 104 directly by the distributed apparatus 204 at a later time. In some other embodiments, the distributed apparatus 204 at 800-5 may provide the central apparatus 202 with all (e.g., upper and lower layer parameters) even if only the upper layer parameters would sent to the UE 104 via RRC signaling. This may be useful to avoid unnecessary signaling or overhead if a lower layer parameter may need to be fetched from the distributed apparatus 204 at a later time. In still further embodiments, the central apparatus 202 at 800-5 may transmit to the distributed apparatus 204 one or more upper layer parameters configured for the UE 104. This may be useful for the distributed apparatus 204 to evaluate whether retransmissions to the central apparatus 202 may be needed due to changes in the upper layer parameters.

[0231] At 800-6 of Fig. 8, the central apparatus 202 may transmit the partial RRC configuration to the UE 104. The partial RRC configuration transmitted by the central apparatus 202 and received by the UE 104 at 800-3 may include at least the first configuration part 602 and the second configuration part 604 as shown in Fig. 6. For example, the first configuration part 602 may be associated with the central apparatus 202 and include actual values or upper layer parameters that have been configured for the UE 104 by the central apparatus 202. The second configuration part 604 may be associated with the distributed apparatus 204 and include one or more placeholders 606 for lower layer parameters to be provided by the distributed apparatus 204 rather than actual values. The second configuration part 604 and / or the placeholder 606 may provide content, names, and / or other information indicative of configuration elements that will be provided to the UE 104 by the distributed apparatus 204.

[0232] In some embodiments, the second configuration part 604 and / or the placeholder 606 may include an identifier of the placeholder 606, a size of the placeholder 606, a parameter for the placeholder 606 to be provided by the distributed apparatus 204, a null element, a type definition, and / or other information that helps the UE 104 identify the information that should be received from the distributed apparatus 204 and / or the manner by which the information received from the distributed apparatus 204 should be merged with the partial RRC configuration. In still further embodiments, the second configuration part 604 and / or the placeholder 606 may be accompanied with an identifier of the distributed apparatus 204 associated with the placeholder 606 that the UE 104 can use to verify or authenticate the distributed apparatus 204 or information received therefrom as will be discussed in more detail below. In some embodiments, the first configuration part 602 and the second configuration part 604 may be transmitted by the central apparatus 202 and received by the UE 104 in a single RRC message or in separate RRC messages. In some examples, the central apparatus 202 may transmit to the UE 104 a list of identifiers (e.g., a list of one-time-use identifiers or the like) at 800-6. In some other examples, the list of identifiers may be transmitted to the UE 104 at some earlier point in time and may not necessarily be bound to the partial RRC configuration.

[0233] At 800-7 of Fig. 8, the central apparatus 202 may optionally transmit to the distributed apparatus 204 information relating to the partial RRC configuration and / or the placeholder 606 that has been sent to the UE 104. For example, the central apparatus 202 may provide an identifier of the placeholder 606 or other information that informs the distributed apparatus 204 where or how the lower layer parameters should be filled into the partial RRC configuration.The information may also include one or more of an indication of the upper layer parameters configured by the central apparatus 202 for the UE 104, an acknowledgement that the placeholder 606 has been configured for the UE 104, an identifier associating the placeholder 606 with the distributed apparatus 204, and / or an indication that the distributed apparatus 204 should expect an acknowledgement from the UE 104. In other embodiments, the exchange at 800-7 may be omitted, e.g., if the information already exchanged at 800-5 is sufficient for the distributed apparatus 204 to configure lower layer parameters for the UE 104 via distributed signaling. In some examples, the central apparatus 202 at 800-7 may also transmit to the distributed apparatus 204 a list of identifiers (e.g., such as the list of identifiers transmitted to the UE 104 at 800-6 or otherwise). In some other examples, the list of identifiers may be transmitted to the distributed apparatus 204 at some earlier point in time and independently of the partial RRC configuration signaling.

[0234] At 800-8 of Fig. 8, the UE 104 may transmit to the central apparatus 202 and / or the distributed apparatus 204 a message acknowledging receipt of the partial RRC configuration. For instance, the UE 104 may transmit the acknowledgement message directly to the distributed apparatus 204, and the distributed apparatus 204 may transmit the acknowledgement message received from the UE 104 to the central apparatus 202. At 800-9, the UE 104 may optionally transmit to the distributed apparatus 204 a separate message acknowledging receipt of the partial RRC configuration and the placeholder 606 designated for lower layer parameters to be provided by the distributed apparatus 204. The message relating to the placeholder 606 at 800-9 may be known to the central apparatus 202, and thus, the distributed apparatus 204 may not need to pass the message to the central apparatus 202. In some embodiments, such as when a one-time-use list of identifiers is in use, the acknowledgement message at 800-9 may comprise an index that indicates which is the next valid identifier entry in the list of identifiers. In some embodiments, the message at 800-9 may be omitted, e.g., if such information is already provided to the distributed apparatus 204 at 800- 8.

[0235] At 800-10, the distributed apparatus 204 may generate, determine, or configure one or more parameters to be used by the UE 104. The parameters may include lower layer parameters to be used in place of the placeholder 606 of the second configuration part 604. For example, the parameters may relate to configurations that govern the access of the UE 104 to the serving cell and / or candidate cells. The configuration may include measurement configurations (e.g., LI reference signal measurement configurations, etc.). The parametersmay also include parameters to be used for initial access (e.g., Master Information Block (MIB), Random Access Channel (RACH), Physical Downlink Control Channel (PDCCH)). In some embodiments, the parameters generated at 800-10 may be generated at an earlier stage, e.g., prior to receiving information relating to the partial RRC configuration and / or the placeholder 606 at 800-5, prior to receiving the information relating to the placeholder 606 at 800-7, prior to receiving the acknowledgement at 800-8 or 800-9, or the like.

[0236] At 800-11 of Fig. 8, the distributed apparatus 204 may transmit the lower layer parameters or configuration elements to the UE 104 using MAC signaling. In some embodiments, the distributed apparatus 204 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the distributed apparatus 204 may provide an identifier of the placeholder 606 that indicates to the UE 104 which placeholder 606 to fill or replace with the lower layer parameters. In some examples, the distributed apparatus 204 may provide an identifier unique to the distributed apparatus 204 that the UE 104 can use for verifying or authenticating the distributed apparatus 204 and / or the lower layer parameters provided therefrom. In some examples, where a list of identifiers is shared by the central apparatus 202, the unique identifier used to complete the RRC configuration may then be removed from the list of identifiers. In one example, an internal pointer of the distributed apparatus 204 may be updated to point to a subsequent identifier in the list of identifiers. The MAC signaling at 800-11 may be triggered as the UE 104 approaches neighbor cells, which may be apparent to the distributed apparatus 204 and / or the central apparatus 202 from measurement reports provided by the UE 104. In case a LTM procedure 300 as in Fig. 3 applies, lower layer parameters or configurations for a target cell should be provided by the distributed apparatus 204 as part of the execution phase 306 rather than the preparation phase 302.

[0237] At 800-12 of Fig. 8, the UE 104 may merge the lower layer parameters provided by the distributed apparatus 204 into the partial RRC configuration provided by the central apparatus 202. For instance, the UE 104 may update or replace the portion of the second configuration part 604 designated by the placeholder 606 with the lower layer parameters provided by the distributed apparatus 204 to complete the RRC configuration. In some embodiments, if the UE 104 is provided with an identifier of the distributed apparatus 204 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the distributed apparatus 204 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard orotherwise not use the lower layer parameters provided by the distributed apparatus 204. If, however, the identifiers match, the UE 104 at 800-12 may use the lower layer parameters provided by the distributed apparatus 204, and at 800-13 transmit to the distributed apparatus 204 a message acknowledging the complete RRC configuration. In some examples, such as when a one-time-use list of identifiers is used, if the identifiers match, the matching identifier may be marked as used or removed from the list. In the case where the list of identifiers is indexed in descending or top-to-bottom order, the matching identifier as well as any preceding identifiers in the list may also be marked as used or removed from the list.

[0238] At 800-14 of Fig. 8, the distributed apparatus 204 may optionally inform the central apparatus 202 that the RRC configuration for the UE 104 is complete. If information relating to the lower layer parameters was not provided to the central apparatus 202 at 800-4, such information may also be included via the indication at 800-14. In some other embodiments, at 800-14, the central apparatus 202 may query the distributed apparatus 204 of the status of the RRC configuration, to which the distributed apparatus 204 may respond and confirm the RRC configuration is complete. In still further embodiments, at 800-15, the UE 104 may also optionally inform the central apparatus 202 that the RRC configuration is complete. At SOO- 16, the UE 104 may activate or use the complete RRC configuration. In some embodiments, the activation may be triggered via the signaling from the distributed apparatus 204 at 800-8 or via separate signaling from the distributed apparatus 204 and / or the central apparatus 202. In some embodiments, the activation may be triggered implicitly e.g., if the identifier provided by the distributed apparatus 204 is verified or authenticated or some other condition.

[0239] At 800-17 of Fig. 8, the UE 104 may proceed to perform measurements of the serving cell and report the measurements to the distributed apparatus 204. Based on the measurements, the distributed apparatus 204 at 800-18 may identify a target cell among one or more candidate cells and determine that a cell change to the target cell needed. At 800-19, the distributed apparatus 204 may transmit to the UE 104 an indication via MAC-CE to activate the cell change and to trigger the UE 104 to change to the target cell. At 800-20, the UE 104 may connect to the target cell.

[0240] Fig. 9 discloses a diagram of one example embodiment 900 of distributed signaling according to the present disclosure. As shown and similar to the embodiment 800 of Fig. 8, the distributed signaling may involve a UE 104, a central apparatus 202 of a serving cell (e.g., Serving CU), and a distributed apparatus 204 (e.g., Serving DU1, DUECelll, DUl :Cell2) that may be associated with the serving cell and one or more other candidate cells. The distributedapparatus 204 may be managed by the central apparatus 202 using a CU-DU split architecture as noted above, and communicate directly with the UE 104 via a distributed signaling. In contrast to the embodiment 800 of Fig. 8, the arrangement of the split or partial RRC configuration according to the embodiment 900 of Fig. 9 may be preconfigured between at least between the central apparatus 202 and the distributed apparatus 204, and thus negotiations such as those performed at 800-3 and 800-4 of Fig. 8 may be omitted.

[0241] At 900-0 of Fig. 9, initial access may be performed, during which the UE 104 may acquire a full RRC configuration (e.g., PDCP, RLC, MAC, and PHY layer parameters) of a given serving cell from the network via the serving central apparatus 202 and / or the serving distributed apparatus 204. At 900-1, the UE 104 may be connected to the serving cell and have a RRC connection with the central apparatus 202. While the UE 104 is in a RRC Connected state, the central apparatus 202 at 900-2 may optionally perform a check to first determine whether the UE 104 supports a split or partial RRC configuration as shown for example in Fig. 6. If the central apparatus 202 determines that the UE 104 does not support partial RRC configurations, the central apparatus 202 and the distributed apparatus 204 may proceed according to conventional RRC configurations. If, however, the central apparatus 202 determines that the UE 104 supports partial RRC configurations, the central apparatus 202 at 900-3 may transmit a partial RRC configuration to the UE 104. In other embodiments, the central apparatus 202 may not need to perform the check at 900-2 prior to transmitting the partial RRC configuration for instance, if the UE 104 is already known to support partial RRC configurations.

[0242] The partial RRC configuration transmitted by the central apparatus 202 and received by the UE 104 at 900-3 may include at least a first configuration part 602 and a second configuration part 604 as shown in Fig. 6. For example, the first configuration part 602 may be associated with the central apparatus 202 and include actual values or upper layer parameters that have been configured for the UE 104 by the central apparatus 202. The second configuration part 604 may be associated with the distributed apparatus 204 and include one or more placeholders 606 for lower layer parameters to be provided by the distributed apparatus 204 rather than actual values. The second configuration part 604 and / or the placeholder 606 may provide content, names, and / or other information indicative of the configuration elements that will be provided to the UE 104 by the distributed apparatus 204.

[0243] In some embodiments, the second configuration part 604 and / or the placeholder 606 may include an identifier of the placeholder 606, a size of the placeholder 606, a parameter forthe placeholder 606 to be provided by the distributed apparatus 204, a null element, a type definition, and / or other information that helps the UE 104 identify the information that should be received from the distributed apparatus 204. In still further embodiments, the second configuration part 604 and / or the placeholder 606 may be accompanied with an identifier of the distributed apparatus 204 associated with the placeholder 606 that the UE 104 can use to verify or authenticate the distributed apparatus 204 or information received therefrom as will be discussed in more detail below. In some embodiments, the partial RRC configuration may be transmitted by the central apparatus 202 and received by the UE 104 in a single RRC message or in separate RRC messages. In some examples, the central apparatus 202 may transmit to the UE 104 a list of identifiers (e.g., a list of one-time-use identifiers or the like) at 900-3. In some other examples, the list of identifiers may be transmitted to the UE 104 at some earlier point in time and may not necessarily be bound to the partial RRC configuration. At 900-4, the UE 104 may transmit to the central apparatus 202 a message acknowledging receipt of the partial RRC configuration.

[0244] At 900-5 of Fig. 9, the central apparatus 202 may transmit to the distributed apparatus 204 information relating to the partial RRC configuration. The information may include one or more of an identifier of the placeholder 606, a size of the placeholder 606, a parameter for the placeholder 606 to be provided by the distributed apparatus 204, a null element, a type definition, or other information that enables the distributed apparatus 204 to provide the UE 104 with lower layer parameters to be used in place of the placeholder 606. In some embodiments, the information may further include an acknowledgement that the placeholder 606 has been configured for the UE 104, and / or an indication that the distributed apparatus 204 should expect an acknowledgement from the UE 104 once the RRC configuration is complete. In some embodiments, the information may also include an indication of one or more parameters that have been configured by the central apparatus 202 and transmitted to the UE 104. In some examples, the central apparatus 202 at 900-5 may also transmit to the distributed apparatus 204 a list of identifiers (e.g., such as the list of identifiers transmitted to the UE 104 at 800-3 or otherwise). In some other examples, the list of identifiers may be transmitted to the distributed apparatus 204 at some earlier point in time and independently of the partial RRC configuration signaling.

[0245] At 900-6 of Fig. 9, the distributed apparatus 204 may generate, determine, or configure one or more parameters to be used by the UE 104. For example, the one or more parameters may include lower layer parameters to be used in place of the placeholder 606 of the secondconfiguration part 604. At 900-7, the distributed apparatus 204 may transmit the lower layer parameters or configurations to the UE 104 using MAC signaling. In some embodiments, the distributed apparatus 204 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the distributed apparatus 204 may provide an identifier of the placeholder 606 that indicates to the UE 104 which placeholder 606 to fill or replace with the lower layer parameters. In some examples, the distributed apparatus 204 may provide an identifier unique to the distributed apparatus 204 that the UE 104 can use for verifying or authenticating the distributed apparatus 204 and / or the lower layer parameters provided therefrom.

[0246] At 900-8 of Fig. 9, the UE 104 may merge the lower layer parameters provided by the distributed apparatus 204 into the partial RRC configuration provided by the central apparatus 202. For instance, the UE 104 may update or replace the portion of the second configuration part 604 designated by the placeholder 606 with the lower layer parameters provided by the distributed apparatus 204 to complete the RRC configuration. In some embodiments, if the UE 104 is provided with an identifier of the distributed apparatus 204 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the distributed apparatus 204 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard or otherwise not use the lower layer parameters provided by the distributed apparatus 204. If, however, the identifiers match, the UE 104 at 900-8 may use the lower layer parameters provided by the distributed apparatus 204, and at 900-9 transmit to the distributed apparatus 204 a message acknowledging the complete RRC configuration. In some examples, such as when a one-time- use list of identifiers is used, if the identifiers match, the matching identifier may be marked as used or removed from the list. In the case where the list of identifiers is indexed in descending or top-to-bottom order, the matching identifier as well as any preceding identifiers in the list may also be marked as used or removed from the list. In some examples, an internal pointer of the distributed apparatus 204 may be updated to point to a subsequent identifier in the list of identifiers

[0247] At 900-10 of Fig. 9, the distributed apparatus 204 may optionally inform the central apparatus 202 that the RRC configuration for the UE 104 is complete. In some other embodiments, at 900-10, the central apparatus 202 may query the distributed apparatus 204 of the status of the RRC configuration, to which the distributed apparatus 204 may respond and confirm the RRC configuration is complete. In still further embodiments, at 900-11, the UE104 may also optionally inform the central apparatus 202 that the RRC configuration is complete. At 900-12, the UE 104 may activate or use the complete RRC configuration. In some embodiments, the activation may be triggered via the signaling from the distributed apparatus 204 at 900-7 or via separate signaling from the distributed apparatus 204 and / or the central apparatus 202. In some embodiments, the activation may be triggered implicitly e.g., if the identifier provided by the distributed apparatus 204 is verified or authenticated or some other condition.

[0248] At 900-13 of Fig. 9, the UE 104 may proceed to perform measurements of the serving cell and report the measurements to the distributed apparatus 204. Based on the measurements, the distributed apparatus 204 at 900-14 may identify a target cell among one or more candidate cells and determine that a cell change to the target cell needed. At 900-15, the distributed apparatus 204 may transmit to the UE 104 an indication via MAC-CE to activate the cell change and to trigger the UE 104 to change to the target cell. At 900-16, the UE 104 may connect to the target cell.

[0249] Fig. 10 discloses a diagram of one example embodiment 1000 of distributed signaling according to the present disclosure. As shown, the distributed signaling may involve a UE 104, a central apparatus 202 of a serving cell (e.g., Serving CU), a first distributed apparatus 204-1 (e.g., Serving DU1, DUECelll, DUl :Cell2) associated with the serving cell and one or more other candidate cells, and a second distributed apparatus 204-2 (e.g., DU2:Cell3) associated with another candidate cell. The embodiment 1000 of Fig. 10 is similar to the embodiment 800 of Fig. 8 and the embodiment 900 of Fig. 9, but further enables distributed signaling with additional network entities, such as the second distributed apparatus 204-2 shown. Many of the features discussed above similarly apply to the embodiment 1000 of Fig. 10 and thus are not all repeated below. However, it will be understood that any of the features already discussed can be similarly applied to embodiment 1000 of Fig. 10.

[0250] At 1000-0 of Fig. 10, initial access may be performed, during which the UE 104 may acquire a full RRC configuration (e.g., PDCP, RLC, MAC, and PHY layer parameters) of a given serving cell from the network via the serving central apparatus 202 and / or the serving distributed apparatus 204-1. At 1000-1, the UE 104 may be connected to the serving cell and have a RRC connection with the central apparatus 202. At 1000-2, the central apparatus 202, the first distributed apparatus 204-1, and the second distributed apparatus 204-2 may optionally agree upon an arrangement for splitting the partial RRC configuration and / or an arrangement for placeholders 606 to be used. In some embodiments, the agreement may be based onnegotiations between the central apparatus 202, the first distributed apparatus 204-1, and the second distributed apparatus 204-2 as in the embodiment 800 of Fig. 8. In other embodiments, the agreement may be predefined as in the embodiment 900 of Fig. 9, in which case the agreement at 1000-2 may be omitted.

[0251] At 1000-3 of Fig. 10, while the UE 104 is in a RRC Connected state, the central apparatus 202 may transmit a partial RRC configuration to the UE 104. The partial RRC configuration may accommodate the second distributed apparatus 204-2 in different ways. In a first example, as shown in Fig. 11, the partial RRC configuration may be comprised of a central unit (CU) configuration part 1102 for the central apparatus 202, and a distributed unit (DU) configuration part 1104 for either of the first distributed apparatus 204-1 or the second distributed apparatus 204-2. In this case, a single placeholder 1106 may be used to reserve the DU configuration part 1104 to be filled with either a first set of parameters 1108-1 provided by the first distributed apparatus 204-1 or a second set of parameters 1108-2 provided by the second distributed apparatus 204-2. As in previous examples, the placeholder 1106 may enable the UE 104 to identify the portion of the partial RRC configuration, or the DU configuration part 1104, that should be filled with lower layer parameters provided by either the first distributed apparatus 204-1 or the second distributed apparatus 204-2.

[0252] In some embodiments, the DU configuration part 1104 and / or the placeholder 1106 may include an identifier of the placeholder 1106, a size of the placeholder 1106, a parameter for the placeholder 1106 to be provided by the first distributed apparatus 204-1 or the second distributed apparatus 204-2, a null element, a type definition, and / or other information that helps the UE 104 identify the information that should be received from the first distributed apparatus 204-1 or the second distributed apparatus 204-2. In still further embodiments, the DU configuration part 1104 and / or the placeholder 1106 may be provided with identifiers of the first distributed apparatus 204-1 and the second distributed apparatus 204-2 that the UE 104 can use to verify or authenticate each of the first distributed apparatus 204-1 and the second distributed apparatus 204-2 or information received therefrom. In some examples, a single identifier may be provided that can identify both of the first distributed apparatus 204-1 and the second distributed apparatus 204-2. In other examples, separate or unique identifiers may be provided that can identify either of the first distributed apparatus 204-1 or the second distributed apparatus 204-2 independently.

[0253] In Fig. 10, the central apparatus 202 may transmit information relating to the partial RRC configuration to the first distributed apparatus 204-1 at 1000-4 and to the seconddistributed apparatus 204-2 at 1000-5. The information may include one or more of an identifier of the placeholder 1106, a size of the placeholder 1106, a parameter for the placeholder 1106 to be provided by the first distributed apparatus 204-1 or the second distributed apparatus 204-2, a null element, a type definition, or other information that enables the first distributed apparatus 204-1 or the second distributed apparatus 204-2 to provide the UE 104 with lower layer parameters to be used in place of the placeholder 1106. In some embodiments, the information may further include an acknowledgement that the placeholder 1106 has been configured for the UE 104, and / or an indication that the first distributed apparatus 204-1 or the second distributed apparatus 204-2 should expect an acknowledgement from the UE 104 once the RRC configuration is complete. In some embodiments, the information may also include an indication of one or more parameters that have been configured by the central apparatus 202 and transmitted to the UE 104

[0254] At 1000-6 of Fig. 10, the first distributed apparatus 204-1 (e.g., associated with the current serving cell) may configure a first set of parameters 1108-1 to be used by the UE 104. For example, the first set of parameters 1108-1 may include lower layer parameters to be used in place of the placeholder 1106 of the DU configuration part 1104. At 1000-7, the first distributed apparatus 204-1 may transmit the lower layer parameters or configurations to the UE 104 using MAC signaling. In some embodiments, the first distributed apparatus 204-1 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the first distributed apparatus 204-1 may provide an identifier of the placeholder 1106 that indicates to the UE 104 which placeholder 1106 to fill or replace with the lower layer parameters. In some examples, the first distributed apparatus 204-1 may provide an identifier unique to the first distributed apparatus 204-1 that the UE 104 can use for verifying or authenticating the first distributed apparatus 204-1 and / or the lower layer parameters provided therefrom.

[0255] In some embodiments, such as when a list of one-time-use identifiers in descending or top-to-bottom list order is used, the list of one-time-use identifiers provided to the UE 104, the first distributed apparatus 204-1, and the second distributed apparatus 204-2 may be identical or specific to the respective first distributed apparatus 204-1 or second distributed apparatus 204-2. In the case where an identical list of identifiers is shared with all distributed apparatuses 204-1 and 204-2, any changes to or removals from the list of identifiers made by the UE 104 should be informed to all distributed apparatuses 204-1 and 204-2. Thus, signaling of such changes (e.g., an index to the next valid identifier entry line number in the list ofidentifiers) may occur after the first distributed apparatus 204-1 sends an identifier at 1000-7, or during synchronization with the second distributed apparatus 204-2 at 1000-11.

[0256] Similar to previous examples, the UE 104 may merge the first set of parameters 1108-1 provided by the first distributed apparatus 204-1 into the partial RRC configuration. For instance, the UE 104 may update or replace the portion of the DU configuration part 1104 designated by the placeholder 1106 with the first set of parameters 1108-1 to complete the RRC configuration. In some embodiments, if the UE 104 is provided with an identifier of the first distributed apparatus 204-1 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the first distributed apparatus 204-1 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard or otherwise not use the first set of parameters 1108-1 provided by the first distributed apparatus 204-1. If, however, the identifiers match, the UE 104 may use the first set of parameters 1108-1, and optionally transmit a message acknowledging receipt of the complete RRC configuration to the first distributed apparatus 204-1 and / or the central apparatus 202.

[0257] At 1000-8 of Fig. 10, the UE 104 may proceed to perform measurements of the serving cell and report the measurements to the first distributed apparatus 204-1. Based on the measurements, the first distributed apparatus 204 at 1000-9 may identify a target cell among one or more candidate cells and determine that a cell change to the target cell needed. At 1000-10, the first distributed apparatus 204-1 may transmit to the UE 104 an indication via MAC- CE to activate the cell change and to trigger the UE 104 to change to the target cell. At 1000-11, the UE 104 may connect to the second distributed apparatus 204-2 associated with the target cell. Similar to the procedures performed by the first distributed apparatus 204-1, the second distributed apparatus 204-2 at 1000-12 may configure a second set of parameters 1108-2 to be used by the UE 104. For example, the second set of parameters 1108-2 may include lower layer parameters to be used in place of the placeholder 1106 of the DU configuration part 1104.

[0258] At 1000-13 of Fig. 10, the second distributed apparatus 204-2 may transmit the lower layer parameters or configurations to the UE 104 using MAC signaling. In some embodiments, the second distributed apparatus 204-2 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the second distributed apparatus 204-2 may provide an identifier of the placeholder 1106 that indicates to the UE 104 which placeholder 1106 to fill or replace with the lower layerparameters. In some examples, the second distributed apparatus 204-2 may provide an identifier unique to the second distributed apparatus 204-2 that the UE 104 can use for verifying or authenticating the second distributed apparatus 204-2 and / or the lower layer parameters provided therefrom.

[0259] Upon receiving the second set of parameters 1108-2 from the second distributed apparatus 204-2, the UE 104 may merge the second set of parameters 1108-2 into the partial RRC configuration initially provided by the central apparatus 202. More specifically, the UE 104 may update or replace the first set of parameters 1108-1 previously provided by the first distributed apparatus 204-1 with the second set of parameters 1108-2. If the UE 104 is provided with an identifier of the second distributed apparatus 204-2 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the second distributed apparatus 204-2 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard or otherwise not use the second set of parameters 1108-2 and retain the first set of parameters 1108-1 for instance. If, however, the identifiers match, the UE 104 may use the second set of parameters 1108-2, and optionally transmit a message acknowledging receipt of the complete RRC configuration to the second distributed apparatus 204-2 and / or the central apparatus 202.

[0260] Referring back to 1000-3 of Fig. 10, the central apparatus 202 may transmit a partial RRC configuration to the UE 104 in a different form to accommodate the second distributed apparatus 204-2. In this second example, as shown in Fig. 12, the partial RRC configuration may be comprised of three configuration parts, including a CU configuration part 1202 for the central apparatus 202, a first DU configuration part 1204-1 for the first distributed apparatus 204-1, and a second DU configuration part 1204-2 for the second distributed apparatus 204-2. In this case, a first placeholder 1206-1 may be used to reserve the first DU configuration part 1204-1 for a first set of parameters 1208-1 from the first distributed apparatus 204-1, and a second placeholder 1206-2 may be used to reserve the second DU configuration part 1204-2 for a second set of parameters 1208-2 from the second distributed apparatus 204-2. Further, the first placeholder 1206-1 may be provided with a first identifier identifying the first distributed apparatus 204-1 associated with the first placeholder 1206-1, and the second placeholder 1206-2 may be provided with a second identifier identifying the second distributed apparatus 204-2 associated with the second placeholder 1206-2 that the UE 104 can use to verify or authenticate each of the first distributed apparatus 204-1 and the second distributed apparatus 204-2 or information received therefrom.

[0261] As in previous examples, the first placeholder 1206-1 may enable the UE 104 to identify the portion of the partial RRC configuration, or the first DU configuration part 1204- 1, that should be filled with the first set of parameters 1208-1, and the second placeholder 1206- 2 may enable the UE 104 to identify the portion of the partial RRC configuration, or the second DU configuration part 1204-2, that should be filled with the second set of parameters 1208-2. The first placeholder 1206-1 and the second placeholder 1206-2 may also be provided with respective identifiers of the first placeholder 1206-1 and the second placeholder 1206-2, respective sizes of the first placeholder 1206-1 and the second placeholder 1206-2, respective parameters for the first placeholder 1206-1 and the second placeholder 1206-2 to be provided by the first distributed apparatus 204-1 and the second distributed apparatus 204-2, respective null elements, respective type definitions, and / or other information that helps the UE 104 identify the information that should be received from the first distributed apparatus 204-1 and the second distributed apparatus 204-2.

[0262] In Fig. 10, the central apparatus 202 may transmit information relating to the partial RRC configuration to the first distributed apparatus 204-1 at 1000-4 and to the second distributed apparatus 204-2 at 1000-5. The information may include one or more of respective identifiers of the first placeholder 1206-1 and the second placeholder 1206-2, respective sizes of the first placeholder 1206-1 and the second placeholder 1206-2, respective parameters to be provided by the first distributed apparatus 204-1 and the second distributed apparatus 204-2, respective null elements, respective type definitions, or other information that enables the first distributed apparatus 204-1 and the second distributed apparatus 204-2 to configure lower layer parameters for the UE 104. In some embodiments, the information may further include an acknowledgement that the first placeholder 1206-1 and the second placeholder 1206-2 have been configured for the UE 104, and / or an indication that the first distributed apparatus 204-1 and the second distributed apparatus 204-2 should expect an acknowledgement from the UE 104 once the RRC configuration is complete. In some embodiments, the information may also include an indication of one or more parameters that have been configured by the central apparatus 202 and transmitted to the UE 104.

[0263] At 1000-6 of Fig. 10, the first distributed apparatus 204-1 (e.g., associated with the current serving cell) may configure a first set of parameters 1208-1 to be used by the UE 104. For example, the first set of parameters 1208-1 may include lower layer parameters to be used in place of the first placeholder 1206-1 of the first DU configuration part 1204-1. At 1000-7, the first distributed apparatus 204-1 may transmit the lower layer parameters or configurationsto the UE 104 using MAC signaling. In some embodiments, the first distributed apparatus 204- 1 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the first distributed apparatus 204-1 may provide an identifier of the first placeholder 1206-1 that indicates to the UE 104 which portion of the first DU configuration part 1204-1 to fill or replace with the lower layer parameters. In some examples, the first distributed apparatus 204-1 may provide an identifier unique to the first distributed apparatus 204-1 that the UE 104 can use for verifying or authenticating the first distributed apparatus 204-1 and / or the lower layer parameters provided therefrom.

[0264] Similar to previous examples, the UE 104 may merge the first set of parameters 1208-1 provided by the first distributed apparatus 204-1 into the partial RRC configuration. For instance, the UE 104 may update or replace the portion of the first DU configuration part 1204 designated by the first placeholder 1206-1 with the first set of parameters 1208-1 to complete the RRC configuration. In some embodiments, if the UE 104 is provided with an identifier of the first distributed apparatus 204-1 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the first distributed apparatus 204-1 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard or otherwise not use the first set of parameters 1208-1 provided by the first distributed apparatus 204-1. If, however, the identifiers match, the UE 104 may use the first set of parameters 1208-1, and optionally transmit a message acknowledging receipt of the complete RRC configuration to the first distributed apparatus 204-1 and / or the central apparatus 202.

[0265] At 1000-8 of Fig. 10, the UE 104 may proceed to perform measurements of the serving cell and report the measurements to the first distributed apparatus 204-1. Based on the measurements, the first distributed apparatus 204 at 1000-9 may identify a target cell among one or more candidate cells and determine that a cell change to the target cell needed. At 1000-10, the first distributed apparatus 204-1 may transmit to the UE 104 an indication via MAC- CE to activate the cell change and to trigger the UE 104 to change to the target cell. At 1000-11, the UE 104 may connect to the second distributed apparatus 204-2 associated with the target cell. Similar to the procedures performed by the first distributed apparatus 204-1, the second distributed apparatus 204-2 at 1000-12 may configure a second set of parameters 1208-2 to be used by the UE 104. For example, the second set of parameters 1208-2 may includelower layer parameters to be used in place of the second placeholder 1206-2 of the second DU configuration part 1204-2.

[0266] At 1000-13 of Fig. 10, the second distributed apparatus 204-2 may transmit the lower layer parameters or configurations to the UE 104 using MAC signaling. In some embodiments, the second distributed apparatus 204-2 may further indicate to the UE 104 to activate, apply, or otherwise use the lower layer parameters to complete the RRC configuration. In some examples, the second distributed apparatus 204-2 may provide an identifier of the second placeholder 1206-2 that indicates to the UE 104 which portion of the second DU configuration part 1204-2 to fill or replace with the lower layer parameters. In some examples, the second distributed apparatus 204-2 may provide an identifier unique to the second distributed apparatus 204-2 that the UE 104 can use for verifying or authenticating the second distributed apparatus 204-2 and / or the lower layer parameters provided therefrom.

[0267] Upon receiving the second set of parameters 1208-2 from the second distributed apparatus 204-2, the UE 104 may merge the second set of parameters 1208-2 into the partial RRC configuration initially provided by the central apparatus 202. For instance, the UE 104 may update or replace the portion of the second DU configuration part 1204-2 designated by the second placeholder 1206-2 with the second set of parameters 1208-2 to complete the RRC configuration. In contrast to previous examples, since the second DU configuration part 1204- 2 is specific to the second set of parameters 1208-2, the first set of parameters 1208-1 of the first DU configuration part 1204-1 may be retained and need not be replaced or overwritten. Furthermore, if the UE 104 is provided with an identifier of the second distributed apparatus 204-2 for verification or authentication purposes, the UE 104 may first determine whether the identifier provided by the second distributed apparatus 204-2 matches or corresponds with an identifier provided by the central apparatus 202. If the identifiers do not match, the UE 104 may discard or otherwise not use the second set of parameters 1208-2. If, however, the identifiers match, the UE 104 may use the second set of parameters 1208-2, and optionally transmit a message acknowledging receipt of the complete RRC configuration to the second distributed apparatus 204-2 and / or the central apparatus 202.

[0268] Although only some example embodiments are provided above, it will be apparent to those of ordinary skill in the relevant art that certain aspects of the above embodiments may be altered and still provide similar effects. Some such further refinements are disclosed below, but the scope of the present disclosure should not be limited thereto.

[0269] In some refinements, a first configuration part and a placeholder of a second configuration part may be provided in a single RRC message or in separate RRC messages. Fig. 13 discloses schematics of exemplary embodiments 1300 for structuring the partial RRC configuration. In a first arrangement, similar to the arrangement referenced in Fig. 6, the partial RRC configuration (C_lp) may be configured to include a first configuration part for upper layer parameters and a second configuration part having a placeholder in a single RRC message 1302. For example, the first configuration part and the second configuration part may be interleaved or otherwise transmitted together in the same RRC message 1302. In a second arrangement, the partial RRC configuration may be configured to be transmitted in separate RRC messages. For example, the first configuration part for upper layer parameters (C l p l) may be transmitted in a first RRC message 1304, and the second configuration part for the placeholder (C_lp_2) may be transmitted in a second RRC message 1306. Using a separate RRC message 1306 for the placeholder may allow for more flexibility in signaling the placeholder to a UE and without altering or impacting the upper layer parameters or configuration elements thereof.

[0270] In some refinements, a UE may be preconfigured with a predefined structure for the partial RRC configuration. For instance, the UE may already expect upper layer parameters for the first configuration part from a central apparatus and expect lower layer parameters for the second configuration part from a distributed apparatus. In such cases, placeholders, or any separate RRC messages therefor, may be omitted. Furthermore, in such cases, each of the central apparatus and the distributed apparatus may exchange or inform one another of the respective configuration parts in order to track the contents of the complete RRC configuration for the UE.

[0271] In some refinements, the second configuration part and / or the placeholder may also indicate which configuration elements of the RRC configuration can be overwritten, updated, or otherwise modified by one or more distributed apparatuses. For instance, the second configuration part may include some actual values that are initially provided by a central apparatus, but can be updated later directly by a distributed apparatus via distributed signaling. In such cases, the central apparatus may provide to a UE an indication of which of those values can be updated by the distributed apparatus. In some embodiments, the indication may be explicit and provided via an additional field of the partial RRC configuration or implicit via an agreement that any RRC value of the second configuration part can be updated by the distributed apparatus. In still further embodiments, the indication may be specific to differentdistributed apparatuses, e.g., indicating specific RRC values that can be modified by specific distributed apparatuses.

[0272] In some refinements, a distributed apparatus may provide a UE with a transaction identifier (e.g., similar to a RRC transaction identifier) along with the lower layer parameters. The transaction identifier may be useful for tracing errors in configuration signaling if errors occur. For instance, and as shown in the RRC IE definition of Fig. 14, the distributed apparatus may wrap a normal RRC configuration into an information element (e.g., element- Transactionldentifier') comprising a transaction identifier that is specific to the distributed apparatus. The RRC transaction identifier may then take on a value of the first configuration part and / or the placeholder provided by a central apparatus. The distributed apparatus may provide the UE the transaction identifier with the lower layer parameters and / or as a separate message (e.g., ElementReconfiguration) as shown in Fig. 14.

[0273] In some refinements, the partial RRC configuration, or one or more of the first configuration part and the second configuration part, may be associated with a version identifier. For instance, the version identifier may comprise a running number that is specific to an entity identifier (e.g., an identifier of a distributed apparatus and / or an identifier of a central apparatus). The version identifier may be used by the network to track different versions or contents of the RRC configuration that may have been changed or updated by different entities at different times. For example, the central apparatus may apply a version identifier corresponding to the second configuration part to the partial RRC configuration transmitted to the UE to enable the UE to identify and pair the partial RRC configuration with subsequent lower layer parameters and configurations from the distributed apparatus.

[0274] Fig. 15 discloses a diagram of one example method 1500 according to some aspects of the present disclosure. The method 1500 may illustrate example operations of a central unit (e.g., a central apparatus 202). Some of the operations illustrated in Fig. 15 may be similar to some operations shown in and described with respect to Fig. 8.

[0275] In an embodiment, the method 1500 may include, at 1502, transmitting, to a user equipment, a partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus including a placeholder for the distributed apparatus; and at 1504, transmitting, to the distributed apparatus, information relating to the placeholder of the second configuration part.

[0276] Fig. 16 discloses a diagram of another example method 1600 according to some aspects of the present disclosure. The method 1600 may illustrate example operations of a distributed unit (e.g., a distributed apparatus 204). Some of the operations illustrated in Fig. 16 may be similar to some operations shown in and described with respect to Fig. 8.

[0277] In an embodiment, the method 1600 may include, at 1602, receiving, from a central apparatus, information relating to a partial RRC configuration for a user equipment including at least a first configuration part associated with the central apparatus and a second configuration part associated with the distributed apparatus including a placeholder for the distributed apparatus; at 1604, determining one or more parameters to be used by the user equipment for the placeholder of the second configuration part; at 1606, transmitting, to the user equipment, the one or more parameters; and at 1608, receiving, from the user equipment, a message acknowledging receipt of the one or more parameters.

[0278] Fig. 17 discloses a diagram of another example method 1700 according to some aspects of the present disclosure. The method 1700 may illustrate example operations of a user equipment (e.g., a UE 104). Some of the operations illustrated in Fig. 17 may be similar to some operations shown in and described with respect to Fig. 8.

[0279] In an embodiment, the method 1700 may include, at 1702, receiving, from a central apparatus, a partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus including a placeholder for the distributed apparatus; at 1704, receiving, from the distributed apparatus, one or more parameters to be used for the placeholder of the second configuration part; at 1706, updating the second configuration part of the partial RRC configuration based on the one or more parameters and the placeholder; and at 1708, transmitting, to the distributed apparatus, a message acknowledging receipt of the one or more parameters.

[0280] Fig. 18 discloses a diagram of another example method 1800 according to some aspects of the present disclosure. The method 1800 may illustrate example operations of a central unit (e.g., a central apparatus 202). Some of the operations illustrated in Fig. 18 may be similar to some operations shown in and described with respect to Fig. 9.

[0281] In an embodiment, the method 1800 may include, at 1802, transmitting, to a distributed apparatus, a request for configuring a partial RRC configuration with at least a first configuration part and a second configuration part for a user equipment, wherein the first configuration part is designated for a first set of parameters and the second configuration partis designated for a second set of parameters by a placeholder; at 1804, receiving, from the distributed apparatus, a response to the request for configuring the partial RRC configuration; at 1806, determining the first set of parameters to be used for the first configuration part; and at 1808, transmitting, to the user equipment, the partial RRC configuration including the first set of parameters to be used for the first configuration part and the placeholder of the second configuration part.

[0282] Fig. 19 discloses a diagram of another example method 1900 according to some aspects of the present disclosure. The method 1900 may illustrate example operations of a distributed unit (e.g., a distributed apparatus 204). Some of the operations illustrated in Fig. 19 may be similar to some operations shown in and described with respect to Fig. 9.

[0283] In an embodiment, the method 1900 may include, at 1902, receiving, from a central apparatus, a request for configuring a partial RRC configuration with at least a first configuration part and a second configuration part for a user equipment, wherein the first configuration part is designated for a first set of parameters and the second configuration part is designated for a second set of parameters by a placeholder; at 1904, transmitting, to the central apparatus, a response to the request for configuring the partial RRC configuration; at 1906, determining the second set of parameters to be used by the user equipment for the placeholder of the second configuration part; at 1908, transmitting, to the user equipment, the second set of parameters; and at 1910, receiving, from the user equipment, a message acknowledging receipt of the second set of parameters.

[0284] Fig. 20 discloses a diagram of another example method 2000 according to some aspects of the present disclosure. The method 2000 may illustrate example operations of a user equipment (e.g., a UE 104). Some of the operations illustrated in Fig. 20 may be similar to some operations shown in and described with respect to Fig. 9.

[0285] In an embodiment, the method 2000 may include, at 2002, receiving, from a central apparatus, a partial RRC configuration including at least a first configuration part configured for a first set of parameters and a second configuration part configured for a second set of parameters including a placeholder for the second set of parameters; at 2004, receiving, from a distributed apparatus, the second set of parameters to be used for the placeholder of the second configuration part; at 2006, updating the second configuration part of the partial RRC configuration based on the second set of parameters and the placeholder; and at 2008, transmitting, to the distributed apparatus, a message acknowledging receipt of the second set of parameters.

[0286] Fig. 21 discloses a diagram of another example method 2100 according to some aspects of the present disclosure. The method 2100 may illustrate example operations of a central unit (e.g., a central apparatus 202). Some of the operations illustrated in Fig. 21 may be similar to some operations shown in and described with respect to Figs. 10 and 11.

[0287] In an embodiment, the method 2100 may include, at 2102, transmitting, to a user equipment, a partial RRC configuration including at least a CU configuration part associated with the central apparatus and a DU configuration part associated with one or more distributed apparatuses including a placeholder for the one or more distributed apparatuses; and at 2104, transmitting, to the one or more distributed apparatuses, information relating to the placeholder of the DU configuration part.

[0288] Fig. 22 discloses a diagram of another example method 2200 according to some aspects of the present disclosure. The method 2200 may illustrate example operations of a user equipment (e.g., a UE 104). Some of the operations illustrated in Fig. 22 may be similar to some operations shown in and described with respect to Figs. 10 and 11.

[0289] In an embodiment, the method 2200 may include, at 2202, receiving, from a central apparatus, a partial RRC configuration including at least a CU configuration part associated with the central apparatus and a DU configuration part associated with one or more distributed apparatuses including a placeholder for the one or more distributed apparatuses; at 2204, receiving, from a first distributed apparatus, a first set of parameters to be used for the DU configuration part; at 2206, updating the DU configuration part of the partial RRC configuration based on the first set of parameters and the placeholder; and at 2208, transmitting, to the first distributed apparatus, a message acknowledging receipt of the first set of parameters.

[0290] Fig. 23 discloses a diagram of another example method 2300 according to some aspects of the present disclosure. The method 2300 may illustrate example operations of a central unit (e.g., a central apparatus 202). Some of the operations illustrated in Fig. 23 may be similar to some operations shown in and described with respect to Figs. 10 and 12.

[0291] In an embodiment, the method 2300 may include, at 2302, transmitting, to a user equipment, a partial RRC configuration including at least a CU configuration part associated with the central apparatus, a first DU configuration part associated with a first distributed apparatus, and a second DU configuration part associated with a second distributed apparatus, wherein the first DU configuration part includes a first placeholder for the first distributed apparatus, and the second DU configuration part includes a second placeholder for the second distributed apparatus; at 2304, transmitting, to the first distributed apparatus, informationrelating to the first placeholder of the first DU configuration part; and at 2306, transmitting, to the second distributed apparatus, information relating to the second placeholder of the second DU configuration part.

[0292] Fig. 24 discloses a diagram of another example method 2400 according to some aspects of the present disclosure. The method 2400 may illustrate example operations of a user equipment (e.g., a UE 104). Some of the operations illustrated in Fig. 24 may be similar to some operations shown in and described with respect to Figs. 10 and 12.

[0293] In an embodiment, the method 2400 may include, at 2402, receiving, from a central apparatus, a partial RRC configuration including at least a CU configuration part associated with the central apparatus, a first DU configuration part associated with a first distributed apparatus, and a second DU configuration part associated with a second distributed apparatus, wherein the first DU configuration part includes a first placeholder for the first distributed apparatus, and the second DU configuration part includes a second placeholder for the second distributed apparatus; at 2404, receiving, from the first distributed apparatus, a first set of parameters to be used for the first DU configuration part; at 2406, updating the first DU configuration part of the partial RRC configuration based on the first set of parameters and the first placeholder; and at 2408, transmitting, to the first distributed apparatus, a message acknowledging receipt of the first set of parameters.

[0294] Fig. 25 is a schematic block diagram of an example embodiment of an apparatus 2500 according to aspects of the present disclosure. The apparatus 2500 may be comprised in or comprised of, for instance, a network node (e.g., network node 102), a user equipment (e.g., UE 104), a central unit (e.g., central apparatus 202), a distributed unit (e.g., distributed apparatus 204), and / or another network entity. As shown, the apparatus 2500 may include at least one or more of a processor 2502, a program memory 2504, a working or main memory 2506, a communication interface 2508, and an optional user interface 2510. Some or all of the components of the apparatus 2500 may for instance be connected via a bus. Some or all of the components of the apparatus 2500 may for instance be combined into one or more modules.

[0295] In some embodiments, the apparatus 2500 (e.g., a network node, a user equipment, a central unit, a distributed unit, or another network entity) may comprise at least one processor 2502, and at least one memory 2504 storing instructions that, when executed by the at least one processor 2502, cause the apparatus 2500 to at least perform and / or control any one of the methods 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400 discussed above. The processor 2502 may for instance further control the memories 2504, 2506, the communicationinterface 2508, and / or the optional user interface 2510. The processor 2502 may execute program code stored in the program memory 2504, which may for instance represent a readable storage medium comprising program code that, when executed by the processor 2502, causes the processor 2502 to perform any one of the methods 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400 discussed above.

[0296] In some embodiments, the apparatus 2500 (e.g., a network node, a user equipment, a central unit, a distributed unit, or another network entity) may be configured to perform and / or control or comprise respective means (e.g., one or more of the processor 2502, the program memory 2504, the working or main memory 2506, the communication interface 2508, and the optional user interface 2510) for performing and / or controlling any one of the methods 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400 discussed above.

[0297] The processor 2502 may be a processor of any suitable type. The processor 2502 may comprise, but is not limited to, one or more microprocessors, one or more processors with accompanying one or more digital signal processors, one or more processors without accompanying digital signal processors, one or more special-purpose computer chips, one or more field-programmable gate arrays (FPGAs), one or more controllers, one or more application-specific integrated circuits (ASICs), one or more computers / servers, or other types of relevant structure / hardware that may be programmed in such a way to perform any one of the methods 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400 discussed above. In some examples, the processor 2502 may be or include an application processor that runs an operating system.

[0298] The program memory 2504 may also be included in the processor 2502. The program memory 2504 may for instance be fixedly connected to the processor 2502, or be at least partially removable from the processor 2502, for instance in the form of a memory card or stick. The program memory 2504 may for instance be non-volatile memory. The program memory 2504 may for instance be or at least partially include a flash memory, a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a hard disc, and / or the like. The program memory 2504 may also comprise an operating system for the processor 2502. The program memory 2504 may also comprise a firmware for the apparatus 2500.

[0299] The communication interface 2508 may enable the apparatus 2500 to communicate with other apparatuses 2500 (e.g., another network node, another user equipment, anothercentral unit, another distributed unit, and / or another network entity). The communication interface 2508 may for instance comprise a wireless interface, e.g. a cellular radio communication interface and / or a WLAN interface) and / or wire-bound interface, e.g. an Internet Protocol (IP)-based interface, for instance, to communicate with entities via the Internet. The communication interface 2508 may enable the apparatus 2500 to communicate with other network entities, for instance, one or more network entities as comprised in a mobile communication network. The user interface 2510 is optional and may comprise a display for displaying information to a user and / or an input device (e.g., a keyboard, a keypad, a touchpad, a mouse, etc.) for receiving information from a user.

[0300] Fig. 26 is a schematic illustration of examples of (tangible and / or non-transitory) computer-readable storage media according to the present disclosure that may for instance be used to implement the program memory 2504 and / or the main memory 2506 of Fig. 25. As shown, the program memory 2504 and / or the main memory 2506 may be implemented using a flash memory 2602, which may for instance be soldered or bonded to a printed circuit board, a solid-state drive 2604 comprising a plurality of memory chips (e.g., flash memory chips), a magnetic hard drive 2606, a Secure Digital (SD) card 2608, a Universal Serial Bus (USB) memory stick 2610, an optical storage medium 2612 (such as for instance a CD-ROM or DVD), a magnetic storage medium 2614, and / or the like.

[0301] In the present disclosure, any presented connection in the described embodiments is to be understood in a way that the involved components are operationally coupled. Thus, the connections can be direct or indirect with any number or combination of intervening elements, and there may be merely a functional relationship between the components.

[0302] Moreover, any of the methods, processes, or actions described or illustrated herein may be implemented using executable instructions in a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, and / or the like) to be executed by such a processor. References to a “computer-readable storage medium” should be understood to encompass specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices.

[0303] The expression “A and / or B” is considered to comprise any one of the following three scenarios: (i) A, (ii) B, (iii) A and B. Furthermore, the article “a” is not to be understood as “one,” i.e., use of the expression “an element” does not preclude that also further elements are present. The term “comprising” is to be understood in an open sense, i.e., in a way that an object that “comprises an element A” may also comprise further elements in addition toelement A. Further, the term “comprising” may be limited to “consisting of,” i.e., consisting of only the specified elements.

[0304] The expression “at least one of the following: (a list of two or more elements)” and “at least one of (a list of two or more elements)” and similar wording, where the list of two or more elements are joined by “and” or “or,” mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0305] It will be understood that all presented embodiments are only examples, and that any feature presented for a particular example embodiment may be used with any aspect on its own or in combination with any feature presented for the same or another particular example embodiment and / or in combination with any other feature not mentioned. In particular, the example embodiments presented in this disclosure shall also be understood to be disclosed in all possible combinations with each other, as far as it is technically reasonable and the example embodiments are not necessarily alternatives with respect to each other. It will further be understood that any feature presented for an example embodiment in a particular category (method / apparatus / computer program / system) may also be used in a corresponding manner in an example embodiment of any other category. It should also be understood that presence of a feature in the presented example embodiments shall not necessarily mean that this feature forms an essential feature and cannot be omitted or substituted.

[0306] The statement of a feature comprises at least one of the subsequently enumerated features is not mandatory in the way that the feature comprises all subsequently enumerated features, or at least one feature of the plurality of the subsequently enumerated features. Also, a selection of the enumerated features in any combination or a selection of only one of the enumerated features is possible. The specific combination of all subsequently enumerated features may as well be considered. Also, a plurality of only one of the enumerated features may be possible.

[0307] The sequence of all method steps presented above is not mandatory, also alternative sequences may be possible. Nevertheless, the specific sequence of method steps exemplarily shown in the drawings shall be considered as one possible sequence of method steps for the respective embodiment described by the respective drawing.

[0308] The subject-matter has been described above by means of examples. It should be noted that there are alternative ways and variations which are obvious to a skilled person in the art and can be implemented without deviating from the scope of the appended claims.PARTIAL GLOSSARY

[0309] C-RNTI Cell Radio Network Temporary Identifier

[0310] CU Central Unit

[0311] DL Downlink

[0312] DU Distributed Unit

[0313] gNB 5G Base Station

[0314] IE Information Elementn

[0315] HO Handover

[0316] LTM L1 / L2 Triggered Mobility

[0317] MAC Medium Access Control

[0318] MAC-CE Medium Access Control-Control Element

[0319] MIB Master Information Block

[0320] NR New Radio (5G)

[0321] NW Network

[0322] PDCCH Physical Downlink Control Channel

[0323] PDCP Packet Data Convergence Protocol

[0324] PHY Physical Layer

[0325] PRS Positioning Reference Signal

[0326] RACH Random Access Channel

[0327] RLC Radio Link Control

[0328] RRC Radio Resource Control

[0329] RS Reference Signal

[0330] RSRP Reference Signal Received Power

[0331] SDAP Service Data Application Protocol

[0332] SCS Subcarrier Spacing

[0333] SRS Sounding Reference Signal

[0334] TA Timing Advance

[0335] TMSI Temporary Mobile Subscriber Identity

[0336] UE User Equipment

[0337] UL Uplink

Claims

CLAIMS:

1. A central apparatus of a network node, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the central apparatus at least to: transmit, to a user equipment, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus of the network node, the second configuration part including a placeholder for the distributed apparatus; and transmit, to the distributed apparatus, information relating to the placeholder of the second configuration part.

2. The central apparatus of claim 1, wherein the information relating to the placeholder includes one or more of an identifier of the placeholder, a size of the placeholder, a parameter for the placeholder to be provided by the distributed apparatus, a null element, a type definition, an identifier of the distributed apparatus associated with the placeholder, an indication of one or more parameters configured by the central apparatus to be transmitted to the user equipment, an acknowledgement that the placeholder has been configured for the user equipment, or an indication that the distributed apparatus should expect an acknowledgement from the user equipment.

3. The central apparatus of any of claims 1-2, further caused to: transmit, to the user equipment with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

4. A distributed apparatus of a network node, comprising: at least one processor; and at least one memory including computer program code, the at least one memory andthe computer program code being configured to, with the at least one processor, cause the distributed apparatus at least to: receive, from a central apparatus of the network node, information relating to a partial radio resource control (RRC) configuration for a user equipment, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with the distributed apparatus, the second configuration part including a placeholder for the distributed apparatus; determine one or more parameters to be used by the user equipment for the placeholder of the second configuration part; transmit, to the user equipment, the one or more parameters; and receive, from the user equipment, a message acknowledging receipt of the one or more parameters.

5. The distributed apparatus of claim 4, wherein the information relating to the partial RRC configuration indicates one or more configuration elements within the second configuration part to be updated by the distributed apparatus.

6. The distributed apparatus of any of claims 4-5, further caused to: transmit, to the user equipment with the one or more parameters, an identifier of the distributed apparatus, the identifier enabling the user equipment to authenticate the distributed apparatus for the placeholder.

7. The distributed apparatus of any of claims 4-6, further caused to: transmit, to the user equipment, one or more further parameters to be used for updating the second configuration part; and receive, from the user equipment, a message acknowledging receipt of the one or more further parameters.

8. A user equipment, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the userequipment at least to: receive, from a central apparatus of a network node, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus of the network node, the second configuration part including a placeholder for the distributed apparatus; receive, from the distributed apparatus, one or more parameters to be used for the placeholder of the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the one or more parameters.

9. The user equipment of claim 8, wherein the placeholder is indicated using one or more of an identifier of the placeholder, a size of the placeholder, the one or more parameters for the placeholder to be provided by the distributed apparatus, a null element, a type definition, or an identifier of the distributed apparatus associated with the placeholder.

10. The user equipment of any of claims 8-9, further caused to: receive, from the central apparatus and with the partial RRC configuration, an identifier of the distributed apparatus associated with the placeholder; receive, from the distributed apparatus with the one or more parameters, an identifier of the distributed apparatus; and update the second configuration part of the partial RRC configuration based on a determination that the identifier received from the distributed apparatus corresponds to the identifier received from the central apparatus.

11. The user equipment of any of claims 8-10, further caused to: receive, from the distributed apparatus, one or more further parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more further parameters and the placeholder; and transmit, to the distributed apparatus, a message acknowledging receipt of the one ormore further parameters.

12. The user equipment of any of claims 8-11, further caused to: receive, from a further distributed apparatus, one or more further parameters to be used for the second configuration part; update the second configuration part of the partial RRC configuration based on the one or more further parameters and the placeholder; transmit, to the further distributed apparatus, a message acknowledging receipt of the one or more further parameters.

13. A method performed by a central apparatus, comprising: transmitting, to a user equipment, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with a distributed apparatus, the second configuration part including a placeholder for the distributed apparatus; and transmitting, to the distributed apparatus, information relating to the placeholder of the second configuration part.

14. A method performed by a distributed apparatus, comprising: receiving, from a central apparatus, information relating to a partial radio resource control (RRC) configuration for a user equipment, the partial RRC configuration including at least a first configuration part associated with the central apparatus and a second configuration part associated with the distributed apparatus, the second configuration part including a placeholder for the distributed apparatus; determining one or more parameters to be used by the user equipment for the placeholder of the second configuration part; transmitting, to the user equipment, the one or more parameters; and receiving, from the user equipment, a message acknowledging receipt of the one or more parameters.

15. A method performed by a user equipment, comprising: receiving, from a central apparatus, a partial radio resource control (RRC) configuration, the partial RRC configuration including at least a first configuration part associated with thecentral apparatus and a second configuration part associated with a distributed apparatus, the second configuration part including a placeholder for the distributed apparatus; receiving, from the distributed apparatus, one or more parameters to be used for the placeholder of the second configuration part; updating the second configuration part of the partial RRC configuration based on the one or more parameters and the placeholder; and transmitting, to the distributed apparatus, a message acknowledging receipt of the one or more parameters.

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