WO2024120741A1

WO2024120741A1 - Admission control enhancement for prioritized users

Info

Publication number: WO2024120741A1
Application number: PCT/EP2023/081397
Authority: WO
Inventors: Pawel MACKOWIAK; Jussi-Pekka Koskinen; Samuli Heikki TURTINEN; Andres ARJONA
Original assignee: Nokia Solutions and Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2022-12-08
Filing date: 2023-11-10
Publication date: 2024-06-13
Anticipated expiration: 2025-06-08
Also published as: CN120304005A; GB202218447D0; GB2625132A

Abstract

Embodiments of the present disclosure relate to an admission control enhancement for prioritized users. In the embodiments, a distributed unit (DU) of a network device transmits, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device. The DU receives, from the CU, a message associated with a second admission control for the connection at the DU. Then, the DU performs the second admission control for the connection based on receiving the message. Moreover, the DU transmits, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection. In this way, the RRC connection can be optimized.

Description

ADMISSION CONTROL ENHANCEMENT FOR PRIORITIZED USERS

FIELD

[0001] Various example embodiments relate to the field of telecommunication and in particular, to methods, devices, apparatuses, and computer readable storage media for an admission control enhancement for prioritized users.

BACKGROUND

[0002] In communication technologies, there is a constant evolution ongoing in order to provide efficient and reliable solutions for utilizing wireless communication networks. Currently, efforts have been made to develop 5th generation (5G) or 5G advance wireless system. The new wireless systems can support various types of service applications for terminal devices.

[0003] In the current wireless system, a user equipment (UE) in a radio resource control (RRC) idle state (also denoted as an RRC_idle state) may initiate, to a network device, a setup procedure to request to be brought into an RRC connected state (also denoted as an RRC connected state) to enable normal data transmission, or to request small data transmission. A UE in the RRC_connected state may initiate, to a network device, a re-establishment procedure to continue the RRC connection when a failure condition occurs (for example, radio link failure, reconfiguration failure, integrity check failure, etc.). A UE in an RRC inactive state (also denoted as an RRC_inactive state) may initiate, to a network device, a resume procedure to request to be brought into the RRC_connected state to enable normal data transmission, or to request small data transmission. However, enhancements on the RRC connection are still in further investigation.

SUMMARY

[0004] In general, example embodiments of the present disclosure provide a solution related to an admission control enhancement for prioritized users.

[0005] In a first aspect, there is provided a distributed unit (DU) of a network device. The DU comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the DU at least to: transmit, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; receive, from the CU, a message associated with a second admission control for the connection at the DU; perform the second admission control for the connection based on receiving the message; and transmit, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[0006] In a second aspect, there is provided a centralized unit (CU) of a network device. The CU comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: receive, from a distributed unit (DU) of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; transmit, to the DU, a message associated with a second admission control for the connection at the DU; and receive, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

[0007] In a third aspect, there is provided a method implemented at a distributed unit (DU) of a network device. The method comprises transmitting, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; receiving, from the CU, a message associated with a second admission control for the connection at the DU; performing the second admission control for the connection based on receiving the message; and transmitting, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[0008] In a fourth aspect, there is provided a method implemented at a centralized unit (CU) of a network device. The method comprises receiving, from a distributed unit (DU) of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; transmitting, to the DU, a message associated with a second admission control for the connection at the DU; and receiving, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

[0009] In a fifth aspect, there is provided an apparatus. The apparatus comprises means for transmitting at a distributed unit (DU) of a network device, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; means for receiving, from the CU, a message associated with a second admission control for the connection at the DU; means for performing the second admission control for the connection based on receiving the message; and means for transmitting, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[0010] In a sixth aspect, there is provided an apparatus. The apparatus comprises means for receiving at a centralized unit (CU) of a network device, from a distributed unit (DU) of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; means for transmitting, to the DU, a message associated with a second admission control for the connection at the DU; and means for receiving, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

[0011] In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above third to fourth aspect.

[0012] In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to perform at least the method according to any one of the above third to fourth aspect.

[0013] In a ninth aspect, there is provided a distributed unit (DU) of a network device. The DU comprises transmitting circuitry configured to transmit, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; receiving circuitry configured to receive, from the CU, a message associated with a second admission control for the connection at the DU; performing circuitry configured to perform the second admission control for the connection based on receiving the message; and circuitry configured to transmit, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[0014] In a tenth aspect, there is provided a centralized unit (CU) of a network device. The CU comprises receiving circuitry configured to receive, from a distributed unit (DU) of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; transmitting circuitry configured to transmit, to the DU, a message associated with a second admission control for the connection at the DU; and receiving circuitry configured to receive, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

[0015] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0017] FIG. 1 illustrates an example environment in which example embodiments of the present disclosure can be implemented;

[0018] FIG. 2 illustrates a signaling flow between the DU and CU of the network device according to some example embodiments of the present disclosure;

[0019] FIG. 3 illustrates a first example communication process between the terminal device and the network device according to some example embodiments of the present disclosure;

[0020] FIG. 4 illustrates a second example communication process between the terminal device and the network device according to some example embodiments of the present disclosure;

[0021] FIG. 5 illustrates a third example communication process between the terminal device and the network device according to some example embodiments of the present disclosure;

[0022] FIG. 6 illustrates a fourth example communication process between the terminal device and the network device according to some example embodiments of the present disclosure;

[0023] FIG. 7 illustrates a flowchart of a method implemented at a DU of a network device according to some embodiments of the present disclosure;

[0024] FIG. 8 illustrates a flowchart of a method implemented at a CU of a network device according to some embodiments of the present disclosure;

[0025] FIG. 9 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and [0026] FIG. 10 illustrates a block diagram of an example of a computer readable medium in accordance with some example embodiments of the present disclosure.

[0027] Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

[0028] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

[0029] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0030] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0031] It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and/or “including”, when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof. As used herein, “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.

[0033] As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable):

(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor s) or a portion of a microprocessor s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0034] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0035] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE), LTE- Advanced (LTE- A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0036] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a New Radio (NR) NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0037] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably. [0038] As described above, A UE in the RRC connected state may initiate the reestablishment procedure to continue the RRC connection when a failure condition (for example, radio link failure, reconfiguration failure, integrity check failure, etc.) occurs. The reestablishment procedure succeeds if the network is able to find and verify a valid UE context. Otherwise, if the UE context cannot be retrieved, the network may determine to fall back to the setup procedure and respond with an RRCSetup message, instead of an RRCReestablishment message.

[0039] However, a problem occurs when the failure condition occurs during a high priority connection such as emergency or priority calls, and an RRC reestablishment procedure is initiated by the UE by transmitting an RRCReestablishmentRequest message which contains no indication of the priority status of the previous connection where failure condition occurred. In other words, in the RRCReestablishmentRequest message, there is no information element (IE) that could indicate the priority of the call. A distributed unit (DU) of the gNB admits the UE and provides the corresponding low layer configuration without the ability to recognize the priority of the request. In case of congestion, non-prioritized RRC re-establishment requests may be not admitted by DU of the gNB due to lack of normal resources, while in fact, prioritized resources could still be available, but unfortunately, the information on priority status is not known at this procedure stage. Similar problems occur in RRC setup or resume procedures, if DU does not decode and inspect the RRC message content that contains establishment cause or resume cause that could be used to recognize priority status of the connection.

[0040] In view of the above, enhancements on a priority indication in the RRC connections shall be considered. Therefore, there is a need for improved RRC connection with the consideration of the priority status information.

[0041] According to embodiments of the present disclosure, there is provided a scheme for an admission control enhancement for prioritized users. With this scheme, a distributed unit (DU) of a network device transmits, to a centralized unit (CU) of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device. The DU receives, from the CU, a message associated with a second admission control for the connection at the DU. The message may indicate priority status information of the connection. Then, the DU performs the second admission control for the connection based on receiving the message. Further, the DU transmits, to the CU, configuration information obtained from the second admission control. The configuration information is associated with the connection. [0042] This scheme optimizes the admission control by indicating the priority status information of the connection and this scheme also applies to the cases where the priority status information is unable to be retrieved and then fallback to the RRC setup procedure. In this way, the network device can prioritize high priority connections (for example, emergency calls or high priority calls) based on the priority status information for example fetched from the old UE context. Thus, the setup procedure, resume procedure, or re-establishment procedure of the emergency calls or high priority calls can be admitted timely.

[0043] Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is first made to FIG. 1, which illustrates an example environment 100 in which example embodiments of the present disclosure can be implemented.

[0044] The environment 100, which may be a part of a communication network, comprises a terminal device 110 and a network device 120 communicating with each other or with other devices via each other.

[0045] The network device 120 may comprise a DU 130 and a CU 140. For example, the DU 130 may be under the control of the CU 140. Some functions of the network device 120 may be deployed on the CU 140, and other functions may be deployed on the DU 130. For example, the CU 140 may be responsible for some higher-layer protocol stack functions and the DU 130 may be responsible for the lower-layer protocol stack functions.

[0046] In the environment 100, the terminal device 110 and the network device 120 can communicate data and control information with each other. A link from the network device 120 to the terminal device 110 is referred to as a downlink (DL), while a link from the terminal device 110 to the network device 120 is referred to as an uplink (UL).

[0047] It is to be understood that the environment 100 shown in FIG. 1 is only for the purpose of illustration without suggesting any limitation as to the scope of the disclosure. F or example, while FIG. 1 depicts the terminal device 110 as a mobile phone, the terminal device 110 may be any type of user equipment.

[0048] It is to be understood that the number of devices and their connection relationships, structures and types as shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The environment 100 may include any suitable number of devices adapted for implementing embodiments of the present disclosure.

[0049] The communications in the environment 100 may follow any suitable communication standards or protocols, which are already in existence or to be developed in the future, such as Universal Mobile Telecommunications System (UMTS), long term evolution (LTE), LTE- Advanced (LTE-A), the fifth generation (5G) New Radio (NR), Wireless Fidelity (Wi-Fi) and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee, and machine type communication (MTC), enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra-reliable low latency communication (URLLC), Carrier Aggregation (CA), Dual Connectivity (DC), and New Radio Unlicensed (NR-U) technologies.

[0050] FIG. 2 illustrates a signaling flow 200 between the DU and CU of the network device according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 200 will be described with reference to FIG. 1.

[0051] As shown in FIG. 2, the DU 130 of the network device 120 transmits (205), to the CU 140 of the network device 120, an admission control indication indicating status of a first admission control at the DU 130 for a connection between the terminal device 110 and the network device 120. For example, the admission control may be referred to as a radio admission control (RAC). Accordingly, the CU 140 receives (210) the admission control indication from the DU 130. By using the admission control indication, the DU 130 may signal to the CU 140 whether the first admission control has been carried out or the result of the first admission control.

[0052] For example, the connection may be a connection to be set up between the terminal device 110 and the network device 120. As another example, the connection may be a connection to be reestablished between the terminal device 110 and the network device 120. As a further example, the connection may be a connection to be resumed between the terminal device 110 and the network device 120.

[0053] In some example embodiments, the DU 140 may perform no admission control. In this case, the admission control indication may indicate ignorance of the first admission control at the DU 130. As an example, the admission control indication may be transmitted in an initial uplink RRC message transfer message. For example, the initial uplink RRC message transfer message may comprise a new IE for example called “No RAC” to be used for the admission control indication. Moreover, in this case, no configuration information, such as lower layer resource allocation, may be generated, and thus no such configuration information may be carried in the initial uplink RRC message transfer message.

[0054] In some other example embodiments, the DU 140 may try to perform the first admission control but it may fail. In this case, the admission control indication may indicate failure of the first admission control at the DU 130. As an example, the admission control indication may be transmitted in an initial uplink RRC message transfer message. For example, the initial uplink RRC message transfer message may comprise a new IE for example called “Failed RAC” to be used for the admission control indication. Similarly, in this case, no configuration information, such as lower layer resource allocation, may be generated, and thus no such configuration information may be carried in the initial uplink RRC message transfer message.

[0055] Then, after receiving the admission control indication from the DU 130, the CU 140 transmits (215), to the DU 130, a message associated with a second admission control for the connection at the DU 130. On the receiving side, the DU 130 receives (220) the message from the CU 140. Then, the DU 130 performs (225) the second admission control for the connection based on receiving the message.

[0056] In some example embodiments, the message may indicate priority status information of the connection. In this case, the second admission control may be performed based on the priority status information. In other words, the DU 130 may accept or reject the connection attempt from the terminal device 110 based on the priority status information. This allows ensuring high priority connections are treated accordingly at the DU 130 over lower priority ones.

[0057] For example, the priority status information may comprise at least one of the following: normal, emergency, highPriority Access, multimedia priority service (mps)-Priority Access, or mission critical service (mcs)-Priority Access. As an example, the priority status information may indicate a priority level of the connection. In this case, different priority levels in a form (PrioLevell, PrioLevel2, etc.) may be supported for further flexibility. As another example, in the example embodiments where the connection is to be reestablished or resumed, the priority status information may indicate a priority level of a connection previously set up for the terminal device 110.

[0058] Alternatively or in addition, the CU 140 may always signal high priority status information to the DU 130 in case previous connection priority status information is not known if the connection is to be reestablished or resumed. In this way, the DU 130 may use available resources, including those dedicated to a prioritized user, to accept the connection attempt, such as the RRC re-establishment request or an RRC resume request, coming from the terminal device 110.

[0059] In some example embodiments, the message may comprise a downlink RRC message transfer message. As an example, the downlink RRC message transfer message may comprise a “priority status” IE to carry the priority status information. Alternatively or in addition, the message may comprise a message requesting the DU 130 to perform the second admission control.

[0060] In the example embodiments where the connection is to be reestablished or resumed between the terminal device 110 and the network device 120, the CU 140 may retrieve a context of the terminal device 110 based at least on receiving the admission control indication. For example, the context may be locally available. As another example, the CU 140 may request the last serving network device to provide the context. The context of the terminal device 110 may comprise previous connection priority status information, such as establishment/resume cause. The previous connection priority status information may be transmitted to the network device 120 by the terminal device 110 during the connection establishment or connection resumption of the previous connection. Then, the CU 140 may transmit the message based on a result of the retrieving of the context. For example, if the context is retrieved successfully, the CU 140 may determine the priority status information based on the retrieved context of the terminal device 110 or resume cause received from the terminal device 110 together with the admission control information and comprise the priority status information in the message. Alternatively, if the CU 140 fails to retrieve the context, the CU 140 may determine to fall back to the RRC setup procedure.

[0061] In the example embodiments where the connection is to be set up between the terminal device 110 and the network device 120, the CU 140 may perform admission control for the connection based at least on receiving the admission control indication. Then, the CU 140 may transmit the message based on a result of the admission control. For example, the CU 140 may determine the priority information for the connection with the terminal device 110 based on the result of the admission control and the establishment cause received from the terminal device 110 together with the admission control information, or the CU 140 may determine to reject the setup of the connection if the admission control fails.

[0062] The DU 130 may obtain configuration information associated with the connection from the second admission control. For example, the configuration information may comprise a resource configuration. As shown in FIG. 2, the DU 130 transmits (230), to the CU 140 the configuration information obtained from the second admission control configuration information. Accordingly, the CU receives (235) the configuration information from the DU 130.

[0063] In some example embodiments, the configuration information may be transmitted to the CU 140 in an uplink RRC message transfer message. As an example, the uplink RRC message transfer message may comprise a “DU to CU RRC Container” IE to carry the configuration information.

[0064] In the example embodiments where the message comprises the message requesting the DU 130 to perform the second admission control, the configuration information may be transmitted to the CU 140 in a message as a response to the request for the DU 130 to perform the second admission control. In the example embodiments where the CU 140 determines to fall back to the RRC setup procedure, the configuration information, such as a lower layer resource configuration, may be transmitted to the CU 140 in the message as the response, and the configuration information may be next used by the CU 140 to prepare an RRC Setup message which is then sent to the DU 130 using, for example, a downlink RRC message transfer message.

[0065] In the example embodiments where the connection is to be reestablished or resumed, and the message is the downlink RRC message transfer message, the downlink RRC message transfer message may comprise an RRC message to be transmitted to the terminal device 110, and may not comprise an identifier (ID) associated with the terminal device 110 allocated by the DU 130 for a connection previously set up for the terminal device 110. In this case, the RRC message may indicate a configuration associated with the connection. And, in this case, if the DU performs the second admission control successfully, the DU 130 may before sending the RRC message to the terminal device 110, update, in the RRC message, the configuration based on the configuration information obtained from the second admission control.

[0066] In some example embodiments, the CU 140 may determine a configuration associated with the connection of the terminal device 110 based on the configuration information received from the DU 130. Then, the CU 140 may transmit to the DU 130, a downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device 110. In this case, the RRC message may indicate the determined configuration. As an example, the RRC message may be an RRCSetup message. As another example, the RRC message may be an RRCResume message. Alternatively or in addition, the RRC message may be an RRCReconfiguration message.

[0067] FIG. 3 illustrates a first example communication process 300 between the terminal device and the network device according to some example embodiments of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to FIG. 1. It would be appreciated that although the process 300 has been described in the network environment 100 of FIG. 1, this process flow may be likewise applied to other communication scenarios. In this case, the terminal device 110 is implemented by a UE 301, the DU 130 of network device 120 is implemented by a gNB-DU 303, and the CU 140 of network device 120 is implemented by a gNB-CU 305.

[0068] As shown in FIG. 3, at 306, the UE 301 transmits a preamble to the gNB-DU 303. At 308, the gNB-DU 303 allocates a new cell radio network temporary identifier (C-RNTI) and a signaling radio bearer 1 (SRB1) configuration, and then, at 310, responds to the UE 301 with a random access response (RAR).

[0069] At 312, the UE 301 transmits an RRCReestablishmentRequest message to the gNB- DU 303, which contains the old C-RNTI and old physical cell identifier (PCI). In this case, the gNB-DU 303 performs no RAC, for example, the RAC refers to the first admission control. At 314, the gNB-DU 303 includes the RRCReesablishmentRequest message in the initial UL RRC message transfer message and transfers the initial UL RRC message transfer message to the gNB-CU 305. The initial UL RRC message transfer message includes the new C-RNTI. Due to the reason that no RAC is performed, no lower layer resource allocation is performed. Thus, the initial UL RRC message transfer message does not comprise the corresponding low layer configuration for the UE 301. The initial UL RRC message transfer message further comprises a new “No RAC” IE to indicate that no RAC is performed, for example the new “No RAC” IE refers to the admission control indication and indicates the ignorance of the first admission control.

[0070] At 316, the gNB-CU 305 retrieves the old UE context. Then, the gNB-CU 305 derives priority status information based on the retrieved old UE context. At 318, the gNB- CU 305 includes an RRCReestablishment message in the DL RRC message transfer message and transfers the DL RRC message transfer message to the gNB-DU 303. For example, the DL RRC message transfer message refers to the message associated with a second admission control for the connection at the gNB-DU 303. If the UE requests to re-establish the RRC connection in the last serving gNB-DU, the DL RRC message transfer message includes the old gNB-DU UE F1AP ID. Then, the DL RRC message transfer message also includes a new “Priority Status” IE to indicate the priority status information of the conneciton.

[0071] At 320, the gNB-DU 303 performs RAC based on the priority status information obtained from the DL RRC message transfer message. For example, the RAC refers to the second admission control and the gNB-DU 303 performs the second admission control based on the priority status information. In case the admission control fails at the gNB-DU 303, RRCReestablishment may not be sent to the UE 301, and the gNB-DU 303 may initiate a context removal request to release the resources also at the gNB-CU 305. Otherwise, if the admission control is successful at the gNB-DU 303, at 322, the gNB-DU 303 retrieves the UE context based on the old gNB-DU UE Fl AP ID, and replaces the old C-RNTI/PCI with the new C-RNTI/PCI. At 324, the gNB-DU 303 transmits the RRCReestablishment message to the UE 301.

[0072] At 326, the UE 301 transmits an RRCReestablishmentComplete message to the gNB- DU 303. At 328, the gNB-DU 303 encapsulates the RRCReestablishmentComplete message in the UL RRC message transfer message and transmits it to the gNB-CU 305. In this case, the UL RRC message transfer message comprises a new “DU to CU RRC Container” IE to carry the configuration information (such as lower layer resource configuration) obtained from the RAC performed at 320, together with the RRCReestablishmentComplete message. The configuration information could be used by the gNB-CU 305 when preparing the RRCReconfiguration message.

[0073] Operations 330-332 and Operations 334-336 are optional. At 330, the gNB-CU 305 triggers a UE context modification procedure by sending the UE context modification request message, which may include data radio bearers (DRBs) to be modified and/or released. At 332, the gNB-DU 303 responses with the UE context modification response message. Alternatively, at 334, the gNB-DU 303 triggers a UE Context modification procedure by sending the UE context modification required message, which may include DRBs to be modified and/or released. At 336, the gNB-CU 305 responses with the UE context modification confirm message.

[0074] It is to be understood that it is assumed that the UE 301 accessed the original gNB-DU where the UE context is available for that UE 301, and either operations 330-332 or operations 334-336 may be executed or both could be skipped. It is also to be understood that if the UE 301 accessed from a gNB-DU other than the original one, the gNB-CU 305 should trigger the UE context setup procedure toward this new gNB-DU 303. [0075] At 338, the gNB-CU 305 includes an RRCReconfiguration message into the DL RRC message transfer message and transfers the DL RRC message transfer message to the gNB-DU 303. For example, the RRCReconfiguraiton may comprise the configuration for the connection based on the configuration information received from the gNB-DU 303, i.e. DU to CU RRC Container” in the UL RRC message transfer message. At 340, the gNB-DU 303 forwards the RRCReconfiguration message to the UE 301.

[0076] At 342, the UE 301 transmits an RRCReconfigurationComplete message to the gNB- DU 303, and at 344, the gNB-DU 303 forwards it in the UL RRC message transfer message to the gNB-CU 305.

[0077] All operations and features as described above with reference to FIG. 2 are likewise applicable to the process 300 and have similar effects. For the purpose of simplification, the details will be omitted.

[0078] FIG. 4 illustrates a second example communication process 400 between the terminal device and the network device according to some example embodiments of the present disclosure. For the purpose of discussion, the process 400 will be described with reference to FIG. 1. It would be appreciated that although the process 400 has been described in the network environment 100 of FIG. 1, this process flow may be likewise applied to other communication scenarios. In this case, the terminal device 400 is implemented by a UE 401, the DU 130 of network device 120 is implemented by a gNB-DU 403, and the CU 140 of network device 120 is implemented by a gNB-CU 405.

[0079] As shown in FIG. 4, at 406, the UE 401 transmits a preamble to the gNB-DU 403. At 408, the gNB-DU 403 allocates a new C-RNTI and an SRB1 configuration, and then, at 410, responds to the UE 401 with a RAR.

[0080] At 412, the UE 401 transmits an RRCReestablishmentRequest message to the gNB- DU 403, which contains the old C-RNTI and old physical cell identifier (PCI). In this case, the gNB-DU 403 performs no RAC, for example, the RAC refers to the first admission control. At 414, the gNB-DU 403 includes the RRCReestablishmentRequest message in the initial UL RRC message transfer message and transfers the initial UL RRC message transfer message to the gNB-CU 405. The initial UL RRC message transfer message includes the new C-RNTI. Due to the reason that no RAC is performed, no lower layer resource allocation is performed. Thus, the initial UL RRC message transfer message does not comprise the corresponding low layer configuration for the UE 401 The initial UL RRC message transfer message further comprises a new “No RAC” IE to indicate that no RAC is performed, for example, the new “No RAC” IE refers to the admission control indication and indicates the ignorance of the first admission control.

[0081] At 416, the gNB-CU 405 determines to fall back to the RRC setup procedure for example for the reason that the old UE context fails to be retrieved successfully. Then, at 418, the gNB-CU 405 transmits a DL RRC message transfer message to the gNB-DU 403. For example, the DL RRC message transfer message refers to the message associated with a second admission control for the connection at the gNB-DU 403. The DL RRC message transfer message includes an RRCSetup message and does not include the old gNB-DU UE F1AP ID, and then the gNB-DU 403 detects the fallback based on the absence of the “old gNB-DU UE F I AP ID” IE.

[0082] At 420, the gNB-DU 403 performs RAC. For example, the RAC refers to the second admission control, and the gNB-DU 403 allocates a new configuration from the RAC. For example, the newly allocated configuration refers to the configuration information. After successful admission control, the gNB-DU 403 updates the lower layer resource configuration provided by the gNB-CU 405 in the RRCSetup message with the newly allocated configuration. At 422, the gNB-DU 403 transmits the RRCSetup message with the updated lower layer resource configuration to the UE 401 . At 424, the UE 401 transmits an RRCSetupComplete message to the gNB-DU 403. At 426, the gNB-DU 403 includes the RRCSetupComplete message in the UL RRC message transfer message together with the newly allocated configuration for example in a new “DU to CU RRC Container” IE for further usage, and transmits the UL RRC message transfer message to the gNB-DU 403. Then, the process 400 continues accordingly.

[0083] All operations and features as described above with reference to FIG. 2 are likewise applicable to the process 400 and have similar effects. For the purpose of simplification, the details will be omitted.

[0084] FIG. 5 illustrates a third example communication process 500 between the terminal device and the network device according to some example embodiments of the present disclosure. For the purpose of discussion, the process 500 will be described with reference to FIG. 1 . It would be appreciated that although the process 500 has been described in the network environment 100 of FIG. 1, this process flow may be likewise applied to other communication scenarios. In this case, the terminal device 500 is implemented by a UE 501, the DU 130 of network device 120 is implemented by a gNB-DU 503, and the CU 140 of network device 120 is implemented by a gNB-CU 505.

[0085] As shown in FIG. 5, at 506, the UE 501 transmits a preamble to the gNB-DU 503. At 508, the gNB-DU 503 allocates a new C-RNTI and an SRB1 configuration, and then, at 510, responds to the UE 501 with a RAR.

[0086] At 512, the UE 501 transmits an RRCReestablishmentRequest message to the gNB- DU 503, which contains old C-RNTI and old physical cell identifier (PCI). In this case, the gNB-DU 503 performs no RAC, for example, the RAC refers to the first admission control. At 514, the gNB-DU 503 includes the RRCReestablishmentReques message in the initial UL RRC message transfer message and transfers the initial UL RRC message transfer message to the gNB-CU 505. The initial UL RRC message transfer message includes the new C-RNTI. Due to the reason that no RAC is performed, no lower layer resource allocation is performed. Thus, the initial UL RRC message transfer message does not comprise the corresponding low layer configuration for the UE 501. The initial UL RRC message transfer message further comprises a new “No RAC” IE to indicate that no RAC is performed, for example, the new “No RAC” IE refers to the admission control indication and indicates the ignorance of the first admission control.

[0087] At 516, the gNB-CU 505 determines to fall back to the RRC setup procedure for example for the reason that the old UE context fails to be retrieved successfully. Then, at 518, the gNB-CU 505 transmits a RAC request to request the gNB-DU 503 to perform the RAC. For example, the RAC refers to a second admission control for the connection at the DU. At 520, the gNB-DU 503 performs the RAC. The gNB-DU 503 may allocate new configuration from the RAC and the newly allocated configuration refers to the configuration information. As an example, the newly allocated configuration comprises the lower layer resource configuration for the connection. After successful admission control, at 522, the gNB-DU 503 transmits a RAC response as a response to the RAC request. The RAC response comprises a “DU to CU RRC Container” IE to carry the allocated lower layer resource configuration. Then, the gNB-CU 505 prepares the RRCSetup message based on the lower layer resource configuration, For example, the RRCSetup may comprise the configuration for the connection based on the lower layer resource configuration received from the gNB-DU 503, i.e. DU to CU RRC Container” in the RAC response.

[0088] The gNB-CU 505 includes the RRCSetup message in the DL RRC message transfer message, and at 524, the gNB-CU 505 transmits the DL RRC message transfer message to the gNB-DU 503. At 526, the gNB-DU 503 transmits the RRCSetup message to the UE 501. [0089] At 528, the UE 501 transmits an RRCSetupComplete message to the gNB-DU 503. At 530, the gNB-DU 503 includes the RRCSetupComplete message in the UL RRC message transfer message, and transmits the UL RRC message transfer message to the gNB-DU 503. Then, the process 500 continues accordingly.

[0090] All operations and features as described above with reference to FIG. 2 are likewise applicable to the process 500 and have similar effects. For the purpose of simplification, the details will be omitted.

[0091] FIG. 6 illustrates a fourth example communication process 600 between the terminal device and the network device according to some example embodiments of the present disclosure. For the purpose of discussion, the process 600 will be described with reference to FIG. 1. It would be appreciated that although the process 600 has been described in the network environment 100 of FIG. 1, this process flow may be likewise applied to other communication scenarios. In this case, the terminal device 110 is implemented by a UE 601, the DU 130 of network device 120 is implemented by a gNB-DU 603, and the CU 140 of network device 120 is implemented by a gNB-CU 605.

[0092] As shown in FIG. 6, at 606, the UE 601 transmits a preamble to the gNB-DU 603. At 608, the gNB-DU 603 allocates a new C-RNTI and an SRB1 configuration, and then, at 610, responds to the UE 601 with a random access response (RAR).

[0093] At 612, the UE 601 transmits an RRCReestablishmentRequest message to the gNB- DU 603, which contains the old C-RNTI and old physical cell identifier (PCI). At 614, the gNB-DU 603 performs preliminary RAC, for example, the preliminary RAC refers to the first admission control. The preliminary RAC may be performed unsuccessfully for example because there are not enough resources. Then, at 616, the gNB-DU 603 includes the RRCReestablishmentRequest message in the initial UL RRC message transfer message and transfers the initial UL RRC message transfer message to the gNB-CU 605. The initial UL RRC message transfer message includes the new C-RNTI. Due to the reason that RAC performed unsuccessfully, no lower layer resource allocation is performed. Thus, the initial UL RRC message transfer message does not comprise the corresponding low layer configuration for the UE 601. The initial UL RRC message transfer message further comprises a new “Failed RAC” IE to indicate that the preliminary RAC is failed, for example, the new “Failed RAC” IE refers to the admission control indication and indicates the failure of the first admission control. [0094] At 618, the gNB-CU 605 retrieves the old UE context. Then, the gNB-CU 605 derives priority status information based on the retrieved old UE context. At 620, the gNB- CU 605 transmits a RAC request to the gNB-DU 603 to request the gNB-DU 603 to reattempt the RAC, and provides the priority status information in the RAC request for example in a “priority status” IE. For example, the RAC refers to a second admission control for the connection at the DU. At 622, the gNB-DU 603 performs the RAC based on the priority status information. For example, the gNB-DU 603 may allocate a new configuration from the RAC and the newly allocated configuration refers to the configuration information. As an example, the newly allocated configuration comprises the lower layer resource configuration for the connection. After successful admission, at 624, the gNB-DU 603 transmits a RAC response as a response to the RAC request. The RAC response comprises a “DU to CU RRC Container” IE to carry the allocated lower layer resource configuration.

[0095] At 626, the gNB-CU 605 includes an RRCReconfiguration message into the DL RRC message transfer message and transfers the DL RRC message transfer message to the gNB-DU 603. For example, the RRCReconfiguraiton may comprise the configuration for the connection based on the configuration information received from the gNB-DU 603, i.e. “DU to CU RRC Container” in the RAC response. At 628, the gNB-DU 603 forwards the RRCReconfiguration message to the UE 601.

[0096] At 630, the UE 601 transmits an RRCReconfigurationComplete message to the gNB- DU 603, and at 632, the gNB-DU 603 forwards it in the UL RRC message transfer message to the gNB-CU 605.

[0097] This example communication process 600 does not require the gNB-DU 603 to decode the received RRC message in order to provide proper resource allocation prioritization.

[0098] All operations and features as described above with reference to FIG. 2 are likewise applicable to the process 600 and have similar effects. For the purpose of simplification, the details will be omitted.

[0099] FIG. 7 illustrates a flowchart 700 of a method implemented at a DU of a network device according to some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the DU 130 of the network device 120 with reference to FIG. 1.

[00100] At block 710, the DU 130 transmits, to the CU 140, of the network device 120, an admission control indication indicating status of a first admission control at the DU 130 for a connection between a terminal device 110 and the network device 120. At block 720, the DU 130 receives, from the CU 140, a message associated with a second admission control for the connection at the DU 130. At block 730, the DU 130 performs the second admission control for the connection based on receiving the message. At block 740, the DU 130 transmits, to the CU 140, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[00101] In some example embodiments, the connection may be a connection to be set up between the terminal device 110 and the network device 120, a connection to be reestablished between the terminal device 110 and the network device 120, a connection to be resumed between the terminal device 110 and the network device 120, or any combination of the listed items.

[00102] In some example embodiments, the admission control indication can be indicative of ignorance of the first admission control at the DU 130, failure of the first admission control at the DU 130, or any combination of the listed items.

[00103] In some example embodiments, the message may comprise a downlink RRC message transfer message, a message requesting the DU 130 to perform the second admission control, or any combination of the listed items.

[00104] In some example embodiments, the message can be indicative of priority status information of the connection, and the second admission control can be performed based on the priority status information.

[00105] In some example embodiments, the priority status information may comprise normal, emergency, highPriorityAccess, multimedia priority service (mps)-PriorityAccess, mission critical service (mcs)-Priority Access, or any combination of the listed items.

[00106] In some example embodiments, the priority status information may indicate a priority level of the connection.

[00107] In some example embodiments, the connection is to be reestablished or resumed, and the priority status information may indicate a priority level of a connection previously set up for the terminal device 110.

[00108] In some example embodiments, the connection is to be reestablished or resumed, and the message is the downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device 110, and not comprising an identifier associated with the terminal device 110 allocated by the DU 130 for a connection previously set up for the terminal device 110, and the RRC message is indicative of a configuration associated with the connection, and the DU 130 may further, subsequent to successfully performing the second admission control, update, in the RRC message, the configuration based on the configuration information obtained from the second admission control.

[00109] In some example embodiments, the configuration information may be transmitted to the CU 140 in an uplink RRC message transfer message, a message as a response to a request for the DU 130 to perform the second admission control, or any combination of the listed items.

[00110] In some example embodiments, the admission control indication may be transmitted in an initial uplink RRC message transfer message.

[00111] FIG. 8 illustrates a flowchart 800 of a method implemented at a CU of a network device according to some embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the CU 140 of the network device 120 with reference to FIG. 1.

[00112] At block 810, the CU 140 receives, from the DU 130, of the network device 120, an admission control indication indicating status of a first admission control for a connection between a terminal device 110 and the network device 120. At block 820, the CU 140 transmits, to the DU 130, a message associated with a second admission control for the connection at the DU 130. At block 830, the CU 140 receives, from the DU 130, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU 130.

[00113] In some example embodiments, the connection may be a connection to be set up between the terminal device 110 and the network device 120, a connection to be reestablished between the terminal device 110 and the network device 120, or a connection to be resumed between the terminal device 110 and the network device 120, or any combination of the listed items.

[00114] In some example embodiments, the admission control indication can be indicative of ignorance of the first admission control at the DU 130, or failure of the first admission control at the DU 130, or any combination of the listed items.

[00115] In some example embodiments, the message may comprise a downlink RRC message transfer message, or a message requesting the DU 130 to perform the second admission control, or any combination of the listed items.

[00116] In some example embodiments, the connection is to be set up between the terminal device 110 and the network device 120, and the CU 140 may further transmit to the DU 130 the message by: performing an admission control for the connection based at least on receiving the admission control indication; and transmitting the message based on a result of the admission control.

[00117] In some example embodiments, the connection is to be reestablished or resumed between the terminal device 110 and the network device 120, and the CU 140 may further transmit to the DU 130 the message by: retrieving a context of the terminal device 110 based at least on receiving the admission control indication; and transmitting the message based on a result of the retrieving of the context.

[00118] In some example embodiments, the message can be indicative of priority status information of the connection. In some example embodiments, the priority status information may comprise normal, emergency, highPriorityAccess, multimedia priority service (mps)- Priority Access, or mission critical service (mcs)-Priority Access, or any combination of the listed items. In some example embodiments, the priority status information may indicate a priority level of the connection. In some example embodiments, the connection is to be reestablished or resumed, and the priority status information may indicate a priority level of a connection previously set up for the terminal device 110, where the priority status information is determined based on a context retrieved for the terminal device 110.

[00119] In some example embodiments, the configuration information may be received in an uplink RRC message transfer message, or a message as a response to a request for the DU 130 to perform the second admission control, or any combination of the listed items.

[00120] In some example embodiments, the CU 140 may further transmit to the DU 130, a downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device 110, and the RRC message can be indicative of a configuration associated with the connection, and the configuration may be determined based on the configuration information received from the DU 130.

[00121] In some example embodiments, the RRC message may be an RRCSetup message, an RRCResume message, or an RRCReconfiguration message, or any combination of the listed items.

[00122] In some example embodiments, the admission control indication may be received in an initial uplink RRC message transfer message.

[00123] In some example embodiments, an apparatus capable of performing the method 700 (for example, the DU 130 of the network device 120) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[00124] In some example embodiments, the apparatus comprises means for transmitting, to a centralized unit, CU, of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; means for receiving, from the CU, a message associated with a second admission control for the connection at the DU; means for performing the second admission control for the connection based on receiving the message; and means for transmitting, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

[00125] In some example embodiments, the connection is at least one of the following: a connection to be set up between the terminal device and the network device; a connection to be reestablished between the terminal device and the network device; or a connection to be resumed between the terminal device and the network device.

[00126] In some example embodiments, the admission control indication is indicative of at least one of the following: ignorance of the first admission control at the DU; or failure of the first admission control at the DU.

[00127] In some example embodiments, the message comprises at least one of the following: a downlink RRC message transfer message; or a message requesting the DU to perform the second admission control.

[00128] In some example embodiments, the message is indicative of priority status information of the connection, and the second admission control is performed based on the priority status information.

[00129] In some example embodiments, the priority status information comprises at least one of the following: normal, emergency, highPriority Access, multimedia priority service (mps)- Priority Access, or mission critical service (mcs)-Priority Access.

[00130] In some example embodiments, the priority status information indicates a priority level of the connection.

[00131] In some example embodiments, the connection is to be reestablished or resumed, and the priority status information indicates a priority level of a connection previously set up for the terminal device. [00132] In some example embodiments, the connection is to be reestablished or resumed, and the message is the downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device, and not comprising an identifier associated with the terminal device allocated by the DU for a connection previously set up for the terminal device, the RRC message being indicative of a configuration associated with the connection, and the apparatus further comprises means for, subsequent to successfully performing the second admission control, updating, in the RRC message, the configuration based on the configuration information obtained from the second admission control.

[00133] In some example embodiments, the configuration information is transmitted to the CU in at least one of the following: an uplink RRC message transfer message; or a message as a response to a request for the DU to perform the second admission control.

[00134] In some example embodiments, the admission control indication is transmitted in an initial uplink RRC message transfer message.

[00135] In some example embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause the performance of the apparatus.

[00136] In some example embodiments, an apparatus capable of performing the method 800 (for example, the CU 140 of the network device 120) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[00137] In some example embodiments, the apparatus comprises means for receiving, from a distributed unit, DU, of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; means for transmitting, to the DU, a message associated with a second admission control for the connection at the DU; and means for receiving, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

[00138] In some example embodiments, the connection is at least one of the following: a connection to be set up between the terminal device and the network device; a connection to be reestablished between the terminal device and the network device; or a connection to be resumed between the terminal device and the network device.

[00139] In some example embodiments, the admission control indication is indicative of at least one of the following: ignorance of the first admission control at the DU; or failure of the first admission control at the DU.

[00140] In some example embodiments, the message comprises at least one of the following: a downlink RRC message transfer message; or a message requesting the DU to perform the second admission control.

[00141] In some example embodiments, the connection is to be set up between the terminal device and the network device, and the means for transmitting to the DU the message comprises: means for performing an admission control for the connection based at least on receiving the admission control indication; and means for transmitting the message based on a result of the admission control.

[00142] In some example embodiments, the connection is to be reestablished or resumed between the terminal device and the network device, and the means for transmitting to the DU the message comprises: means for retrieving a context of the terminal device based at least on receiving the admission control indication; and means for transmitting the message based on a result of the retrieving of the context.

[00143] In some example embodiments, the message is indicative of priority status information of the connection. In some example embodiments, the priority status information comprises at least one of the following: normal, emergency, highPriorityAccess, multimedia priority service (mps)-PriorityAccess, or mission critical service (mcs)-Priority Access. In some example embodiments, the priority status information indicates a priority level of the connection. In some example embodiments, the connection is to be reestablished or resumed, and the priority status information indicates a priority level of a connection previously set up for the terminal device, the priority status information being determined based on a context retrieved for the terminal device.

[00144] In some example embodiments, the configuration information is received in at least one of the following: an uplink RRC message transfer message; or a message as a response to a request for the DU to perform the second admission control.

[00145] In some example embodiments, the apparatus further comprises: means for transmitting to the DU, a downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device, the RRC message being indicative of a configuration associated with the connection, and the configuration is determined based on the configuration information received from the DU. In some example embodiments, the RRC message is at least one of the following: an RRCSetup message; an RRCResume message; or an RRCReconfiguration message.

[00146] In some example embodiments, the admission control indication is received in an initial uplink RRC message transfer message.

[00147] In some example embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 800. In some embodiments, the means comprises at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause the performance of the apparatus.

[00148] FIG. 9 illustrates a simplified block diagram of a device 900 that is suitable for implementing some example embodiments of the present disclosure. The device 900 may be provided to implement the communication device, for example, the terminal device 110, or the DU 130 or the CU 140 of the network device 120 as shown in FIG. 1. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

[00149] The communication module 940 is for bidirectional communications. The communication module 940 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[00150] The processor 910 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 900 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[00151] The memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 924, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 922 and other volatile memories that will not last in the power-down duration.

[00152] A computer program 930 includes computer executable instructions that are executed by the associated processor 910. The program 930 may be stored in the ROM 924. The processor 910 may perform any suitable actions and processing by loading the program 930 into the RAM 922.

[00153] The embodiments of the present disclosure may be implemented by means of the program 930 so that the device 900 may perform any process of the disclosure as discussed with reference to FIGS. 2 to 6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[00154] In some example embodiments, the program 930 may be tangibly contained in a computer readable medium which may be included in the device 900 (such as in the memory 920) or other storage devices that are accessible by the device 900. The device 900 may load the program 930 from the computer readable medium to the RAM 922 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

[00155] FIG. 10 illustrates a block diagram of an example of a computer readable medium 1000 in accordance with some example embodiments of the present disclosure. The computer readable medium 1000 has the program 930 stored thereon. It is noted that although the computer readable medium 1000 is depicted in form of CD or DVD in FIG. 10, the computer readable medium 1000 may be in any other form suitable for carry or hold the program 930.

[00156] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[00157] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method as described above with reference to any of FIGS. 7-8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[00158] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[00159] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[00160] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a readonly memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM). [00161] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

[00162] Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A distributed unit, DU, of a network device, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the DU at least to: transmit, to a centralized unit, CU, of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; receive, from the CU, a message associated with a second admission control for the connection at the DU; perform the second admission control for the connection based on receiving the message; and transmit, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

2. The DU of claim 1, wherein the connection is at least one of the following: a connection to be set up between the terminal device and the network device; a connection to be reestablished between the terminal device and the network device; or a connection to be resumed between the terminal device and the network device.

3. The DU of claim 1 or 2, wherein the admission control indication is indicative of at least one of the following: ignorance of the first admission control at the DU; or failure of the first admission control at the DU.

4. The DU of any of claims 1-3, wherein the message comprises at least one of the following: a downlink RRC message transfer message; or a message requesting the DU to perform the second admission control.

5. The DU of any of claims 1-4, wherein: the message is indicative of priority status information of the connection, and the second admission control is performed based on the priority status information.

6. The DU of claim 5, wherein the priority status information comprises at least one of the following: normal, emergency, highPriority Access, multimedia priority service (mps)- Priority Access, or mission critical service (mcs)-Priority Access.

7. The DU of claim 5, wherein the priority status information indicates a priority level of the connection.

8. The DU of claim 5, wherein the connection is to be reestablished or resumed, and wherein the priority status information indicates a priority level of a connection previously set up for the terminal device.

9. The DU of claim 4, wherein the connection is to be reestablished or resumed, and wherein the message is the downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device, and not comprising an identifier associated with the terminal device allocated by the DU for a connection previously set up for the terminal device, the RRC message being indicative of a configuration associated with the connection, and the DU is further caused to: subsequent to successfully performing the second admission control, update, in the RRC message, the configuration based on the configuration information obtained from the second admission control.

10. The DU of any of claims 1-9, wherein the configuration information is transmitted to the CU in at least one of the following: an uplink RRC message transfer message; or a message as a response to a request for the DU to perform the second admission control.

11. The DU of any of claims 1-10, wherein the admission control indication is transmitted in an initial uplink RRC message transfer message.

12. A centralized unit, CU, of a network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the CU at least to: receive, from a distributed unit, DU, of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; transmit, to the DU, a message associated with a second admission control for the connection at the DU; and receive, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

13. The CU of claim 12, wherein the connection is at least one of the following: a connection to be set up between the terminal device and the network device; a connection to be reestablished between the terminal device and the network device; or a connection to be resumed between the terminal device and the network device.

14. The CU of claim 12 or 13, wherein the admission control indication is indicative of at least one of the following: ignorance of the first admission control at the DU; or failure of the first admission control at the DU.

15. The CU of any of claims 12-14, wherein the message comprises at least one of the following: a downlink RRC message transfer message; or a message requesting the DU to perform the second admission control.

16. The CU of any of claims 12-15, wherein the connection is to be set up between the terminal device and the network device, and wherein the CU is caused to transmit to the DU the message by: performing an admission control for the connection based at least on receiving the admission control indication; and transmitting the message based on a result of the admission control.

17. The CU of any of claims 12-15, wherein the connection is to be reestablished or resumed between the terminal device and the network device, and wherein the CU is caused to transmit to the DU the message by: retrieving a context of the terminal device based at least on receiving the admission control indication; and transmitting the message based on a result of the retrieving of the context.

18. The CU of any of claims 12-17, wherein the message is indicative of priority status information of the connection.

19. The CU of claim 18, wherein the priority status information comprises at least one of the following: normal, emergency, highPriority Access, multimedia priority service (mps)- Priority Access, or mission critical service (mcs)-Priority Access.

20. The CU of claim 18, wherein the priority status information indicates a priority level of the connection.

21 . The CU of claim 18, wherein the connection is to be reestablished or resumed, and wherein the priority status information indicates a priority level of a connection previously set up for the terminal device, the priority status information being determined based on a context retrieved for the terminal device.

22. The CU of any of claims 12-21, wherein the configuration information is received in at least one of the following: an uplink RRC message transfer message; or a message as a response to a request for the DU to perform the second admission control.

23. The CU of any of claims 12-22, wherein the CU is further caused to: transmit to the DU, a downlink RRC message transfer message comprising an RRC message to be transmitted to the terminal device, the RRC message being indicative of a configuration associated with the connection, and wherein the configuration is determined based on the configuration information received from the DU.

24. The CU of claim 23, wherein the RRC message is at least one of the following: an RRCSetup message; an RRCResume message; or an RRCReconfiguration message.

25. The CU of any of claims 12-24, wherein the admission control indication is received in an initial uplink RRC message transfer message.

26. A method comprising: transmitting, at a distributed unit, DU, of a network device, to a centralized unit, CU, of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; receiving, from the CU, a message associated with a second admission control for the connection at the DU; performing the second admission control for the connection based on receiving the message; and transmitting, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

27. A method comprising: receiving, at a centralized unit, CU, of a network device, from a distributed unit, DU, of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; transmitting, to the DU, a message associated with a second admission control for the connection at the DU; and receiving, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

28. An apparatus comprising: means for transmitting, at a distributed unit, DU, of a network device, to a centralized unit, CU, of the network device, an admission control indication indicating status of a first admission control at the DU for a connection between a terminal device and the network device; means for receiving, from the CU, a message associated with a second admission control for the connection at the DU; means for performing the second admission control for the connection based on receiving the message; and means for transmitting, to the CU, configuration information obtained from the second admission control, the configuration information being associated with the connection.

29. An apparatus comprising: means for receiving, at a centralized unit, CU, of a network device, from a distributed unit, DU, of the network device, an admission control indication indicating status of a first admission control for a connection between a terminal device and the network device; means for transmitting, to the DU, a message associated with a second admission control for the connection at the DU; and means for receiving, from the DU, configuration information associated with the connection, the configuration information being obtained from the second admission control at the DU.

30. A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 26 or 27.