CN109587756B

CN109587756B - Method and apparatus for network access

Info

Publication number: CN109587756B
Application number: CN201711120988.5A
Authority: CN
Inventors: 汪巍崴; 柯小婉; 王弘; 许丽香
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-09-28
Filing date: 2017-11-13
Publication date: 2022-07-29
Anticipated expiration: 2037-11-13
Also published as: CN109587756B9; CN109587756A

Abstract

The embodiment of the invention provides a method and equipment for network access. The method comprises the steps of receiving a first request message forwarded by a distribution unit in a base station and indication information of the distribution unit aiming at the first request message, wherein the first request message requests to connect user equipment to a network; determining processing of the first request message based on the indication information; and sending an indication for the determined processing to the distribution unit.

Description

Method and apparatus for network access

Technical Field

The embodiment of the invention relates to a wireless communication technology, in particular to a method and equipment for network access.

Background

In a New Radio access (NR) network or a fifth generation (5G) network, a base station (e.g., gNB) providing a wireless network interface for a terminal (UE) may be further divided into a central unit cu and a distributed unit du (distributed unit) in order to support network function virtualization, more efficient resource management and scheduling. The CU has at least Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP) Protocol layers, and the like, and may also include a Service Data Adaptation Protocol (SDAP). The DU has a radio link control protocol, protocol (RLC), Medium Access Control (MAC), and physical layer, etc. Between CU and DU is a standardized public interface F1. The F1 interface is divided into a control plane F1-C and a user plane F1-U. The transport network layer of F1-C is based on IP transport. For more reliable transport signaling, the SCTP protocol is added on top of IP. The protocol of the application layer is F1 AP. SCTP can provide reliable application layer message transport. The transport layer of F1-U is UDP/IP, and GTP-U is used to carry user plane protocol data units PDU on top of UDP/IP.

In the existing system, a user needs to access a base station, and possible flows include an RRC connection setup flow (RRC connection setup procedure), an RRC connection restart flow (RRC connection resume procedure), and an RRC connection reestablishment flow (RRC connection reestablishment procedure). These procedures may result in the user not being able to successfully connect to the network due to insufficient resources on the base station side or other reasons. However, the prior art does not consider the handling of the case where the user cannot successfully connect to the network in the case where the base station comprises a centralized unit and a distributed unit.

Therefore, a technical solution is required to cope with such a situation.

Disclosure of Invention

According to an aspect of an embodiment of the present invention, there is provided a method for network access, the method including:

receiving a first request message forwarded by a distribution unit in a base station and indication information of the distribution unit aiming at the first request message, wherein the first request message requests to connect user equipment to a network;

determining processing of the first request message based on the indication information; and

sending an indication of the determined processing to the distribution unit.

For example, processing the first request message may include one of: generating a connection establishment message or a connection restart message or a connection reestablishment message; starting a process of establishing user context to trigger the resource allocation of the distribution unit to the user; and generating a rejection message for the first request message.

For example, the rejection message indicates a rejection of connecting the user equipment to the network, and generating the rejection message may include: generating the rejection message based on not accepting the request to connect the user device to a network; or generating a rejection message for the first request message based on a response message indicating that the user context establishment fails, wherein the response message is a response message for a second request message for establishing the user context, which is transmitted to the distribution unit.

For example, determining processing of the first request message further comprises generating a permission message for the first request message, the permission message indicating permission to connect the user equipment to a network. In this case, the method may further include: sending the allowance message to the distribution unit in addition to the rejection message.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The method may further comprise: receiving the reason of the user access network forwarded by the distribution unit; determining processing of the first request message based on the forwarded reason for the user to access the network and the reason for the user to access the network, which is acceptable to the distribution unit, included in the indication information.

forwarding a first request message received from a user equipment and indication information for the first request message to a concentration unit in a base station, the first request message requesting to connect the user equipment to a network;

receiving an indication of processing of the first request message from the central unit; and

processing the first request message based on the indication.

For example, the indication of processing of the first request message comprises an indication of one of: receiving and forwarding a connection establishment message or a connection restart message or a connection reestablishment message; triggering resource allocation to the user based on a flow established by the user context; and receiving and forwarding a rejection message for the first request message.

For example, the method may further comprise: after transmitting the first request message to the concentration unit, receiving a second request message for establishing a user context from the concentration unit in the base station, generating a response message indicating a user context establishment failure based on not accepting a request to connect the user equipment to a network, and transmitting the response message to the concentration unit in the base station. Alternatively, the method may further comprise: receiving an allowance message from the central unit indicating allowance of connection of the user equipment to the network, and selecting one of the rejection message and the allowance message to send to the user equipment based on whether the user equipment can be connected to the network.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The method may further comprise: forwarding a reason for accessing the network by the user to the concentration unit, so that the concentration unit determines the processing of the first request message based on the forwarded reason for accessing the network by the user and the reason for accessing the network by the user, which is acceptable by the distribution unit and is included in the indication information.

According to an aspect of the embodiments of the present invention, there is provided a central unit device in a base station for network access, including:

a message receiving module, configured to receive a first request message forwarded by a distribution unit in a base station and indication information of the distribution unit for the first request message, where the first request message requests a user equipment to connect to a network;

a message processing module to determine processing of the first request message based on the indication information; and

a message sending module to send an indication of the determined processing to the distribution unit.

For example, processing of the first request message may include one of: generating a connection establishment message or a connection restart message or a connection reestablishment message; starting a process of establishing user context to trigger the resource allocation of the distribution unit to the user; and generating a rejection message for the first request message.

For example, the rejection message indicates a rejection of connecting the user equipment to a network, the message processing module may be operable to: generating the rejection message based on not accepting the request to connect the user device to a network; or generating a rejection message for the first request message based on a response message indicating that the user context establishment fails, wherein the response message is a response message for a second request message for establishing the user context, which is transmitted to the distribution unit.

For example, the message processing module may be configured to generate a permission message for the first request message, the permission message indicating permission to connect the user equipment to a network. In this case, the message sending module is configured to: sending the allowance message to the distribution unit in addition to the rejection message.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The message receiving module is used for: and receiving the reason for the user to access the network forwarded by the distribution unit. The message processing module may be configured to determine processing of the first request message based on a reason for the forwarded user to access the network and a reason for the user to access the network, which is acceptable to the distribution unit, included in the indication information.

According to another aspect of the embodiments of the present invention, there is provided a distribution unit device of a base station for network access, including:

a first message receiving module for receiving a first request message from a user equipment, the first request message requesting to connect the user equipment to a network;

a first message sending module, configured to forward the first request message and indication information for the first request message to a central unit in a base station;

a second message receiving module for receiving an indication of processing of the first request message from the central unit; and

a message processing module to process the first request message based on the indication.

For example, the second message receiving module is configured to: after sending the first request message to the concentration unit, receiving a second request message for establishing a user context from the concentration unit in the base stations. The message processing module is used for: generating a response message indicating a user context setup failure based on not accepting the request to connect the user device to the network. The first message sending module is configured to send the response message to the central unit in the base station. Or, the second message receiving module is configured to: receiving a permission message from the central unit indicating permission to connect the user equipment to a network. The message determination module is to: selecting one of the rejection message and the allowance message to send to the user equipment based on whether the user equipment can be connected to a network.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The first message sending module is further configured to: forwarding a reason for accessing the network by the user to the concentration unit, so that the concentration unit determines the processing of the first request message based on the forwarded reason for accessing the network by the user and the reason for accessing the network by the user, which is acceptable by the distribution unit and is included in the indication information.

According to another aspect of the embodiments of the present invention, there is provided an apparatus for network access, including:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the one processor to be executed by the at least one processor to enable the at least one processor to perform a method according to an embodiment of the invention.

Depending on the embodiment performed, the above-mentioned devices may be distributed units or centralized units in the base station.

According to another aspect of embodiments of the present invention, there is provided a computer-readable storage medium having stored thereon executable instructions that, when executed by a processor, cause the processor to perform a method according to embodiments of the present invention.

According to the technical scheme of the embodiment of the invention, when the resources at the base station side are insufficient and the user cannot be successfully connected to the network, the rejection of the user connection request by the centralized unit or the distributed unit is completed through the message interaction between the centralized unit and the distributed unit.

Drawings

Fig. 1 is a diagram illustrating a connection relationship between a CU and a DU according to an embodiment of the present invention;

fig. 2 shows a flow diagram of a method for network access implemented in a centralized unit according to an embodiment of the invention;

fig. 3 shows a flow diagram of a method for network access implemented in a distribution unit according to an embodiment of the invention;

fig. 4 shows a schematic block diagram of an apparatus for network access corresponding to the method of fig. 2;

fig. 5 shows a schematic block diagram of an apparatus for network access corresponding to the method of fig. 3;

FIG. 6 is a diagram illustrating one example of a connection request of a user being rejected by a concentration unit according to an embodiment of the present invention;

fig. 7 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 6, according to an embodiment of the present invention;

FIG. 8 is a diagram illustrating another example of a hub unit rejecting a user's connection request in accordance with an embodiment of the present invention;

FIG. 9 illustrates a timing diagram of a user connection request rejection method of the scenario illustrated in FIG. 8, in accordance with an embodiment of the present invention;

FIG. 10 is a diagram illustrating one example of a distribution unit rejecting a user's connection request, according to an embodiment of the present invention;

FIG. 11 illustrates a timing diagram of a user connection request rejection method of the scenario illustrated in FIG. 10, in accordance with an embodiment of the present invention;

FIG. 12 shows a schematic diagram of another example of a distribution unit rejecting a connection request of a user according to an embodiment of the invention;

fig. 13 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 12, according to an embodiment of the present invention;

FIG. 14 shows a schematic diagram of another example of a distribution unit rejecting a connection request of a user according to an embodiment of the invention;

FIG. 15 is a timing diagram illustrating a user connection request rejection method of the scenario of FIG. 14, in accordance with an embodiment of the present invention;

15-1 through 15-6 illustrate schematic flow diagrams for processing connection request messages based on indications of a central unit in accordance with embodiments of the present invention; and

fig. 16 schematically shows a block diagram of a base station according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below with reference to the accompanying drawings. It should be noted that the following description is intended for illustration only and is not intended to limit the present disclosure. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that: these specific details need not be employed to practice the present disclosure. In other instances, well-known circuits, materials, or methods have not been described in detail in order to avoid obscuring the present disclosure.

Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Furthermore, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The names of the messages involved in the present invention are examples only, and other names may be adopted.

Fig. 1 shows a schematic diagram of a connection relationship between a CU and a DU according to an embodiment of the present invention. As shown in FIG. 1, the CUs and DUs communicate via a control plane interface F1-C and a user plane interface F1-U.

It is to be noted that the connection relationship shown in fig. 1 is merely an example. In other examples, one CU may also be connected to multiple DUs. In some examples, the CU and DU may be physically co-located, e.g., in the same room, on the same rack, or even on the same circuit board. However, in other examples, the CU and the DU may be far away from each other. Embodiments of the present invention are not limited to the connection shown in fig. 1.

When the base station includes the central unit and the distribution unit as shown in fig. 1, the RRC connection establishment procedure, the RRC connection restart procedure, the RRC connection reestablishment procedure, and the like need to be completed by the central unit and the distribution unit together. If a user is not successfully connected to the network, either because the centralized unit cannot accommodate the user or the distributed unit cannot accommodate the user. The prior art does not consider the case where the base station comprises a concentration unit and a distribution unit. The reason for the inability of the hub to accommodate the user (or the inability to connect the user device to the network) as described herein may be that there are insufficient resources at the hub to accommodate the user, congestion at the hub occurs, the hub is unable to obtain a user context, or any other reason that may cause the inability of the user device of the user to connect to the network at the hub. The reason for the inability of the distribution unit to accommodate the user (or to connect the user device to the network) described herein may be that the resources at the distribution unit are insufficient to accommodate the user, congestion occurs at the distribution unit, or any other reason that may cause the user device of the user to be unable to connect to the network at the distribution unit. Furthermore, the concentration unit and the distribution unit may also be able to accommodate a user, but may be reluctant to accept connection of the user's user equipment to the network for some reason (e.g., the respective load policies of the concentration unit and the distribution unit, etc.). The technical solution of the embodiment of the present invention is also applicable to such a case. Therefore, unless explicitly stated otherwise, in the following description of the embodiments of the present invention, the cases such as "unable to accept", "unable to connect", and "unable to access" may also include the cases such as "unwilling to accept", "unwilling to connect", and "unwilling to access".

For this purpose, the solutions according to fig. 2 and 3 are made. Fig. 2 illustrates a method 200 for network access implemented in a centralized unit in accordance with an embodiment of the invention. As shown in fig. 2, in step S210, a first request message forwarded by a distribution unit in a base station and indication information of the distribution unit for the first request message are received, where the first request message requests to connect a user equipment to a network.

According to a specific embodiment of the present invention, the first request message may be one of a connection setup request message, a connection restart request message, and a connection reestablishment request message. Of course, the first request message may also be any message currently used in the art or used in the future for requesting the user equipment to connect to the network.

In step S220, processing of the first request message is determined based on the indication information.

The processing of the first request message according to the above steps may include one of:

generating a connection establishment message or a connection restart message or a connection reestablishment message;

starting a process of establishing user context to trigger the resource allocation of the distribution unit to the user; and

generating a rejection message for the first request message.

The rejection message may be a connection rejection message or a connection reestablishment rejection message, or any other message having a corresponding form, corresponding to the specific form of the first request message. For example, if the first request message is a connection setup request message/connection restart request message, the reject message is a connection reject message, and if the first request message is a connection reestablishment request message, the reject message is a connection reestablishment reject message. Of course, in some embodiments, the message may also include the above-mentioned rejection message.

As described above, the connection request of the user may be rejected due to the centralized unit or due to the distributed unit. In the former case, the rejection message may be generated based on the central unit not accepting the request to connect the user equipment to the network. In the latter case, the rejection message may be generated based on the feedback from the distribution unit, or the rejection message may be directly generated and sent to the distribution unit, and the distribution unit itself may decide whether or not to adopt the rejection message. For example, a second request message for establishing the user context may be sent to the distribution unit, and a response message indicating that the user context establishment fails and sent by the distribution unit may be received, and a rejection message for the first request message may be generated based on the response message. For example, information may be received from the distribution unit indicating that the distribution unit refuses to connect the user equipment to the network, and a refusal message may be generated based on the information.

The indication information also includes the reason for the user to access the network, which is acceptable to the distribution unit. In this case, the method shown in fig. 2 may further include: receiving a reason for accessing the network by the user forwarded by the distribution unit (the reason information may be included in the first request message or may be obtained by the distribution unit through the first request message); determining processing of the first request message based on the forwarded reason for the user to access the network and the reason for the user to access the network, which is acceptable to the distribution unit, included in the indication information.

Then, in step S230, an instruction for the determined process is transmitted to the distribution unit.

Fig. 3 illustrates a method 300 implemented in a distribution unit for network access, in accordance with an embodiment of the invention. As shown in fig. 3, in step S310, a first request message received from a user equipment, which requests to connect the user equipment to a network, and indication information for the first request message are forwarded to a concentration unit.

In step S320, an indication of processing of the first request message is received from the central unit.

The indication of the processing of the first request message may comprise one of:

receiving and forwarding a connection establishment message or a connection restart message or a connection reestablishment message;

triggering resource allocation to the user based on a flow established by the user context; and

receiving and forwarding a rejection message for the first request message.

In particular embodiments, for example, a response message indicating a failure in establishing the user context may be generated based on the distribution unit not accepting the request to connect the user device to the network after receiving the second request message for establishing the user context from the concentration unit and sent to the concentration unit for generating a rejection message by the concentration unit based on the response message. For example, information indicating that the distribution unit rejects connecting the user equipment to the network may be generated and sent to the concentration unit based on the distribution unit not accepting the request to connect the user equipment to the network, so that the concentration unit can generate a rejection message based on the information. For example, the distribution unit may not feedback to the concentration unit whether it is able to connect the user equipment to the network, but receive from the concentration unit both the rejection message and an allowance message indicating allowance to connect the user equipment to the network, and select one of the rejection message and the allowance message based on whether the distribution unit is able to connect the user equipment to the network. The permission message described herein also takes a form corresponding to the first request message, for example, if the first request message is a connection setup request message, the permission message is a connection setup message, if the first request message is a connection restart request message, the permission message is a connection restart message or a connection setup message, and if the first request message is a connection reestablishment request message, the permission message is a connection reestablishment message.

The indication information may further include a reason why the user that is acceptable to the distribution unit accesses the network. The method shown in fig. 3 may further include: and forwarding a reason for accessing the network by the user (the reason information may be included in the first request message or obtained by the distribution unit through the first request message) to the concentration unit, so that the concentration unit determines to process the first request message based on the reason for accessing the network by the forwarded user and the reason for accessing the network by the user acceptable to the distribution unit, which are included in the indication information.

Then, in step S330, the first request message is processed based on the indication.

Fig. 4 and 5 also show block diagrams of devices corresponding to the methods shown in fig. 2 and 3. Fig. 4 shows a schematic block diagram of an apparatus 400 for network access corresponding to the method of fig. 2. As shown in fig. 4, the apparatus 400 includes a message receiving module 410, a message processing module 420, and a message transmitting module 430. The message receiving module 410 is configured to receive a first request message forwarded by a distribution unit, the first request message requesting to connect the user equipment to a network, and indication information of the distribution unit for the first request message. Message processing module 420 is configured to determine processing of the first request message based on the indication information. A message sending module is to send an indication of the determined processing to the distribution unit.

For example, the rejection message indicates a rejection of connecting the user equipment to the network. The message processing module 420 is further configured to: the rejection message is generated based on the device 400 not accepting a request to connect the user device to the network.

The message sending module 430 is further configured to send a second request message for establishing a user context to the distribution unit, for example. The message receiving module 410 is further configured to receive a response message sent by the distribution unit and indicating that the user context setup fails. The message processing module 420 is further configured to generate a reject message for the first request message based on the response message.

For example, the message processing module 420 is further configured to generate an allowance message for the first request message, the allowance message indicating that the user equipment is allowed to connect to the network. The message sending module 430 is further configured to: the grant message is sent to the distribution unit in addition to the rejection message.

As described above, the response message and the permission message may respectively take a form corresponding to the first request message.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The message receiving module 410 is further configured to receive a reason for the user to access the network forwarded by the distribution unit (the reason information may be included in the first request message or obtained by the distribution unit through the first request message). In this case, the message processing module 420 is further configured to determine processing of the first request message based on the forwarded reason for accessing the network by the user and the reason for accessing the network by the user, which is acceptable to the distribution unit, included in the indication information.

The device 400 shown in fig. 4 may also include a memory 440 for storing data used in denying user access. The data may, for example, include user-related information, such as identification information of the user, and/or cell identification information of the user, and/or RRC messages of the user, etc. Such user-related information may be deleted from memory 440 before (e.g., after having determined to send) or after the rejection message is sent to the distribution unit. The memory 440 may be implemented in any form commonly used in the art and will not be described herein.

Fig. 5 shows a schematic block diagram of an apparatus 500 for network access corresponding to the method of fig. 3. The apparatus 500 shown in fig. 5 includes a first message receiving module 510, a first message transmitting module 520, a second message receiving module 530, and a message processing module 550. The first message receiving module 510 is configured to receive a first request message from a user equipment, the first request message requesting to connect the user equipment to a network. The first message sending module 520 is configured to forward the first request message and indication information for the first request message to the central unit. The second message receiving module 530 is configured to receive an indication of processing of the first request message from the central unit. Message processing module 550 is configured to process the first request message based on the indication.

The indication of processing of the first request message comprises an indication of one of: receiving and forwarding a connection establishment message or a connection restart message or a connection reestablishment message; triggering resource allocation to the user based on a flow established by the user context; and receiving and forwarding a rejection message for the first request message.

For example, the second message receiving module 530 is further configured to receive a second request message for establishing a user context from the central unit after sending the first request message to the central unit. The message processing module 550 is configured to generate a response message indicating a failure of the user context setup based on the device 500 not accepting the request to connect the user device to the network. The first message sending module 520 is further configured to send the response message to the central unit.

The second message receiving module 530 is further configured to receive a permission message from the central unit indicating permission to connect the user equipment to the network, for example. The apparatus 500 shown in fig. 5 may further include a message determination module 560 for selecting one of a reject message and an allow message for transmission to the user equipment based on whether the apparatus 500 is capable of connecting the user equipment to the network.

For example, the indication information further includes a reason why the user that is acceptable for the distribution unit accesses the network. The first message sending module 520 is further configured to forward a reason for accessing the network by the user (the reason information may be included in the first request message or obtained by the distribution unit through the first request message) to the central unit, so that the central unit determines to process the first request message based on the forwarded reason for accessing the network by the user and the reason for accessing the network by the user, which is acceptable by the distribution unit and included in the indication information.

The apparatus shown in fig. 5 may further comprise a second message sending module 540 for sending a rejection message or various other information, e.g. received from the central unit, to the user.

Similar to the device shown in fig. 4, the device 500 shown in fig. 5 may further include a memory 570 for storing data used in denying user access. The data may, for example, include user-related information, such as identification information of the user, and/or cell identification information of the user, and/or RRC messages of the user, etc. Such user-related information may be deleted from the memory 570 before (e.g., after having determined to send) or after the rejection message is sent to the user device. The memory 570 may be implemented in any form commonly used in the art and will not be described in detail herein.

By adopting the technical scheme, the centralized unit or the distributed unit can reject the user connection request.

Various implementation details according to embodiments of the invention will be set forth below with reference to fig. 6-15. It is noted that the following description is set forth with the base station including a concentration unit and a distribution unit. The base station may be a base station of NR (gNB), a base station of LTE (eNB), or any other base station that includes a centralized unit and a distributed unit or that can implement the functions of a base station. Further, the following messages are referred to in the following description, however, these message names are only examples, and any other names may be adopted:

connection rejection message (e.g. RRCConnectionReject)

Connection reestablishment reject message (e.g., RRCConnectionReestabilishment reject)

Connection establishment request message (e.g. RRCConnectionRequest)

Connection restart request message (e.g. RRCConnectionResumRequest)

Connection reestablishment request message (e.g. RRCConnectionReestabilishment request)

Connection setup message (e.g. RRCConnectionSetup)

Connection restart message (e.g. RRCConnectionResume)

Connection reestablishment message (e.g. RRCConnectionReestablistment)

In addition, the names of the messages referred to below are merely examples, and any other names may be used.

Depending on the specific situation, the connection request of the user may be rejected due to the centralized unit or due to the distributed unit. In the following description, the technical solutions of the embodiments of the present invention will be specifically explained for these two cases.

In the first case: connection establishment request/connection restart request/connection reestablishment request refused by centralized unit

In this case, the concentration unit may send a connection establishment rejection message/connection re-establishment rejection message to the distribution unit. The message may be sent in two ways:

the method comprises the following steps: the central unit sends to the distribution unit via a non-UE associated F1AP message, such as a Final downlink RRC message transfer (Final DL RRC message). Fig. 6 shows a schematic diagram of this case. At least one of the following information may be included in the message:

■ RRC message generated by centralized unit, such as connection rejection message or connection reestablishment rejection message

■ identification information of the user, e.g. C-RNTI

■ user identification information assigned by the central unit for use on the interface between the central unit and the distribution units, e.g. CU UE F1AP ID

■ user identification information distributed by the distribution unit for use on the interface between the concentration unit and the distribution unit, e.g. DU UE F1AP ID

■ Cell identification information, such as pci (physical Cell Identity), nci (NR Cell Identity), NR CGI (NR Cell Global Identity), etc., the Cell identification information is the identification of the Cell where the user is located

After receiving the non-user-related message, the distribution unit may consider that an RRC message (such as a connection reject message or a connection reestablishment reject message) included in the message indicates rejection of the connection request of the user, and send the connection request to the user. The related information of the user, such as the identification information of the user, and/or the cell identification information of the user, and/or the RRC message of the user, etc., may be deleted before or after sending the RRC message to the user.

Similarly, the central unit may delete the user related information, such as the user identification information, and/or the user cell identification information, and/or the user RRC message, before or after sending the non-user related message to the distribution unit.

Fig. 7 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 6, according to an embodiment of the present invention. As shown in fig. 7:

step 1: a user sends a connection establishment request message/a connection restart request message/a connection reestablishment request message to a distribution unit;

step 2: the distribution unit sends a non-UE associated message (non-UE associated F1AP message), such as an Initial UL RRC message transfer, to the central unit, which may include at least one of the following information:

■ connection setup request message/connection restart request message/connection re-establishment request message received in step 1

■ identification information of the user, e.g. C-RNTI

■ Cell identification information, such as PCI (physical Cell Identity), NCI (NR Cell Identity), NR CGI (NR Cell Global Identity), etc., indicating that the user is in the Cell to send the message in step 1

And step 3: the central unit sends a non-UE associated message (non-UE associated F1AP message), such as a Final DL RRC message transfer, to the distribution unit, which may contain at least one of the following information:

■ the central unit generates a connection rejection message or a connection reestablishment rejection message. For example, if the connection establishment request message/connection restart request message is received in step 2, the message sent in step 3 is a connection rejection message, and if the connection reestablishment request message is received in step 2, the message sent in step 3 is a connection reestablishment rejection message;

■ identification information of the user, e.g. C-RNTI

■ Cell id information, such as pci (physical Cell Identity), nci (NR Cell Identity), NR CGI (NR Cell Global Identity), etc., which is the same as the Cell id information received by the central unit in step 2

And 4, step 4: the distribution unit sends the message received in step 3 (i.e. the connection rejection message or the connection re-establishment rejection message) to the user.

In the above procedure, the central unit may release the information related to the user before or after step 3, such as the user identification information (e.g. CU UE F1AP ID) allocated by the central unit and used on the interface between the central unit and the distribution unit, and/or the user identification information (e.g. DU UE F1AP ID) allocated by the distribution unit and used on the interface between the central unit and the distribution unit, and/or the identity of the user (e.g. C-RNTI), and/or the cell identity of the cell where the user is located, and/or the information related to the user (e.g. connection establishment request message/connection restart request message/connection re-establishment request message/connection reject message/connection re-establishment reject message, etc.). After step 3, the distribution unit may release user related information, such as user identification information (e.g. CU UE F1AP ID) allocated by the concentration unit for use on the interface between the concentration unit and the distribution unit, and/or user identification information (e.g. DU UE F1AP ID) allocated by the distribution unit for use on the interface between the concentration unit and the distribution unit, and/or an identification of the user (e.g. C-RNTI), and/or the cell where the user is located, and/or user related information (e.g. connection establishment request message/connection restart request message/connection re-establishment request message/connection reject message/connection re-establishment reject message, etc.) before or after sending the connection reject message/connection re-establishment reject message to the user.

The method 2 comprises the following steps: the message is sent to the user through a user-associated message (UE-associated F1AP message), such as downlink RRC message transfer (DL RRC message). Fig. 8 shows a schematic diagram of this case. At least one of the following information may be included in the message:

■ connection rejection message or connection reestablishment rejection message generated by centralized unit

■ identification information of the user, e.g. C-RNTI

■ configuration information (such as identification of Signaling Radio Bearer, and/or configuration information of RLC layer, and/or configuration information of logical channel, etc.) of Signaling Radio Bearer (SRB: Signaling Radio Bearer), which may be the first Signaling Radio Bearer (SRB 1 in TS36.331 or TS38.331)

After receiving the user-related message, the distribution unit sends an RRC message (e.g., a connection reject message or a connection reestablishment reject message) included in the message to the user, and deletes user-related information before or after sending the RRC message to the user, such as user identification information (e.g., CU UE F1AP ID) allocated by the concentration unit and used on an interface between the concentration unit and the distribution unit, and/or user identification information (e.g., C-RNTI) allocated by the distribution unit and used on an interface between the concentration unit and the distribution unit, such as DU UE F1AP ID, and/or user identification information (e.g., C-RNTI), and/or cell identification information of the user, and/or an RRC message of the user, and/or configuration information of a signaling radio bearer. The distribution unit may decide whether to delete the related information of the user before or after sending the RRC message to the user according to the content in the user-related message. If the content in the user-related message is one of the following situations, the distribution unit may determine that the user-related message includes a connection rejection message or a connection reestablishment rejection message:

case 1: the subscriber-related message does not contain subscriber identity information assigned by the concentrator unit for use at the interface between the concentrator unit and the distribution unit, such as the CU UE F1AP ID

Case 2: the subscriber-related message does not contain subscriber identity information assigned by the distribution unit for use at the interface between the concentration unit and the distribution unit, e.g. the DU UE F1AP ID

Case 3: the user-related message does not contain the configuration information of the signaling radio bearer

Case 4: any combination of the above three conditions

The distribution unit may delete the user's related information before or after sending the RRC message to the user.

Before or after the central unit sends the user-related message to the distribution unit, the central unit may delete the user-related information, such as user identification information (e.g. CU UE F1AP ID) allocated by the central unit and used on the interface between the central unit and the distribution unit, and/or user identification information (e.g. DU UE F1AP ID) allocated by the distribution unit and used on the interface between the central unit and the distribution unit, and/or user identification information (e.g. C-RNTI), and/or user cell identification information, and/or user RRC message, and/or configuration information of signaling radio bearer, etc

Fig. 9 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 8, according to an embodiment of the present invention. As shown in fig. 9:

step 2: the distribution unit sends a non-user related message (e.g., Initial UL RRC message transfer) to the central unit, where the message may include at least one of the following information:

■ user ID information, e.g. user ID information assigned by C-RNTI concentration unit and used on the interface between concentration unit and distribution unit, e.g. CU UE F1AP ID

And step 3: the central unit sends a user-related message (e.g., DL RRC message transfer) to the distribution unit, where the message may include at least one of the following information:

■ identification information of the user, e.g. C-RNTI

■ configuration information of Signaling Radio Bearer (Signaling Radio Bearer), such as identification of Signaling Radio Bearer, and/or configuration information of RLC layer, and/or configuration information of logical channel, etc

In the above procedure, the central unit may release the information related to the user before or after step 3, such as the user identification information allocated by the central unit and used on the interface between the central unit and the distribution unit (e.g. CU UE F1AP ID), and/or the user identification information allocated by the distribution unit and used on the interface between the central unit and the distribution unit, such as DU UE F1AP ID, and/or the identity of the user (e.g. C-RNTI), and/or the cell where the user is located, and/or the information related to the user (e.g. connection establishment request message/connection restart request message/connection re-establishment request message/connection reject message/connection re-establishment reject message, etc.), and/or the configuration information of the Signaling Radio Bearer (Signaling Radio Bearer). After receiving the message related to the user in step 3, the distribution unit determines whether to release the information related to the user according to the content in the message related to the user. If the release is decided, the distribution unit may release the information related to the user before or after sending the RRC message included in step 3 to the user, such as user identification information (e.g. CU UE F1AP ID) allocated by the central unit and used on the interface between the central unit and the distribution unit, and/or the identification of the user (e.g. C-RNTI), and/or the cell where the user is located, and/or the information related to the user (e.g. connection establishment request message/connection restart request message/connection reestablishment request message/connection rejection message/connection reestablishment rejection message, etc.), and/or the configuration information of the Signaling Radio Bearer (Signaling Radio Bearer).

In some examples, neither the user-related messages nor the non-user-related messages described above may have corresponding messages that are fed back by the receiving node. Such messages are referred to in the protocol (e.g., TS36.423, TS38.423, TS38.473) as second type messages (Class2 messages). In yet other examples, there may also be feedback messages for user-related messages or non-user-related messages.

In the second case: connection establishment request/connection restart request/connection reestablishment request refused by distribution unit

In this case, one of the following three methods may be employed to reject the connection establishment request/connection restart request/connection reestablishment request of the user:

the method comprises the following steps: sending connection establishment rejection/connection reestablishment rejection only after user context establishment fails

Fig. 10 shows a schematic diagram of this case. As shown in fig. 10, the method defines a non-user related message or a user related message that the central unit sends to the distribution unit. If the message is a non-user related message (e.g. Final downlink RRC message transfer), the content of the message, the sending of the message, and the operation of the central unit and the distribution unit may be referred to as method 1 in the first case; in case of a user-related message (e.g. a DL RRC message transfer), the content of the message, the transmission of the message, and the operation of the central unit and the distribution unit may be referred to as method 2 in the first case.

Fig. 11 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 10, according to an embodiment of the present invention. As shown in fig. 11:

■ identification information of the user, e.g. C-RNTI

■ resource allocation related information of the distribution unit, comprising at least one of the following information:

configuration information of Signaling Radio Bearer (Signaling Radio Bearer), such as identification of Signaling Radio Bearer, and/or configuration information of RLC layer, and/or configuration information of logical channel, etc., the Signaling Radio Bearer may be the first Signaling Radio Bearer (SRB 1 in TS36.331 or TS38.331)

Parameter configuration information related to MAC layer and physical layer

The resource allocation related information of the distribution unit may be within one information element (e.g. radioResourceConfigDedicated in 36.331) or within multiple information elements

And step 3: the central unit sends a user context setup request message to the distribution unit, which may contain at least one of the following information:

■ centralize the RRC messages generated by the elements. If the step 2 receives the connection establishment request message, the step 3 contains the connection establishment message, if the step 2 receives the connection restart request message, the step 3 contains the connection restart message or the connection establishment message, if the step 2 receives the connection restart request message, the step 3 contains the connection reestablishment message, if the step 2 receives the connection reestablishment request message, the step 3 contains the connection reestablishment message

■ identification information of the user, e.g. C-RNTI

■ cause information for the user to establish or restart or reestablish the connection, such as cause information included in the connection establishment request message sent by the user in step 1 (e.g. emergency occurrence, high priority Access highpriority Access, data needed to send mt-Access to the user, user-initiated signaling mo-signaling, user-initiated data sending mo-data, delay tolerant Access delaytraceccess, user-initiated voice mo-VoiceCall, etc.), or cause information included in the connection restart request message sent by the user in step 1 (e.g. emergency occurrence, high priority Access highpriority Access, data needed to send mt-Access to the user, user-initiated signaling mo-naling, user-initiated data sending mo-data, delay tolerant Access taygonanceto the user, user-initiated voice-signaling, etc.), cause information included in the connection reestablishment request message sent by the user in step 1 (e.g. call failure reason information, etc.), handover failure, other failure otherFailure, etc.). The above reason information can be found in TS36.331 and TS 38.331.

■ configuration information of Signaling Radio Bearer (Signaling Radio Bearer), such as identification of Signaling Radio Bearer, and/or configuration information of RLC layer, and/or configuration information of logical channel, etc., the Signaling Radio Bearer can be the first Signaling Radio Bearer (SRB 1 in TS36.331 or TS38.331)

And 4, step 4: the distribution unit sends a user context setup failure message to the central unit, the message indicating that the distribution unit does not accept (cannot or is unwilling) the connection request of the user, and the message may contain at least one of the following information:

■ identification information of the user, e.g. C-RNTI

■ the distribution unit does not accept (cannot or is not willing to) an indication message of the user who sent the message to the distribution unit in step 1, such as a rejection indication message, a congestion indication message, etc

■ reject reason information for establishing user context, such as insufficient resources, resource congestion, etc

And 5: the central unit sends non-user related messages (e.g., final downlink RRC messaging) or user related messages (e.g., downlink RRC messaging) to the distribution units. If the Final downlink RRC message transmission message (Final DL RRC message transfer) is sent, the content of the message, the sending of the message, and the operation of the central unit and the distribution unit may be referred to as method 1 in the first case, where the message includes a connection setup rejection message/a connection reestablishment rejection message. If a downlink RRC message transmission message (DL RRC message transfer) is sent, the content of the message, the sending of the message, and the operations of the central unit and the distribution unit may refer to method 2 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message;

step 6: the distribution unit sends the received connection establishment rejection message/connection reestablishment rejection message to the user

The user context setup request message and the user context setup failure message in step 3 and step 4 are only examples, and may also be messages with other names, where the message with other names may be a message that does not need to be replied by the receiving node (referred to as a second type message (Class2 message) in the protocol (e.g. TS36.423, TS38.423, TS38.473, etc.), or may also be a message that needs to be replied by the receiving node (referred to as a first type message (Class 1 message) in the protocol (e.g. TS36.423, TS38.423, TS38.473), and the above user context setup request message is a Class1 message because it needs to receive a user context setup response message or a user context setup failure message fed back by the distribution unit). If step 3 can be a message that does not require the distribution unit to feed back a reply, step 4 can be any other message than the message sent by the central unit. Or in step 3a message to be replied to by the distribution unit, the distribution unit replies in step 4 to the message received in step 3.

In this embodiment, for the case that the context is successfully established, after step 3, if the distribution unit considers that the user context establishment request of the central unit can be accepted, before feeding back the user context establishment response message to the central unit, the distribution unit may send an RRC message included in the user context establishment request message (if the connection establishment request message is received in step 2, the connection establishment message is included in step 3, if the connection restart request message is received in step 2, the connection restart message or the connection establishment message is included in step 3, if the connection reestablishment request message is received in step 2, the connection reestablishment message is included in step 3) to the user, and then the distribution unit sends the user context establishment response message to the central unit.

The method 2 comprises the following steps: including a connection establishment rejection message/a connection reestablishment rejection message in the user context establishment request message

Fig. 12 shows a schematic diagram of this case. The method defines the following process for establishing the user context between the centralized unit and the distributed unit:

step 1: the central unit sends a user context setup request message to the distribution unit, which may contain at least one of the following information:

■ RRC messages generated by the central unit, such as connection setup messages and/or connection setup rejection messages, connection restart request messages and/or connection setup rejection messages, connection re-establishment messages and/or connection re-establishment rejection messages

■ identification information of the user, e.g. C-RNTI

Step 2: the distribution unit sends a user context setup failure message to the central unit indicating that the distribution unit does not accept (cannot or is unwilling) the user's connection request, which may contain at least one of the following information:

■ identification information of the user, e.g. C-RNTI

■ the distribution unit does not accept (cannot or is not willing to) indication messages of users sending messages to the distribution unit, such as rejection indication messages, congestion indication messages, etc

The user context setup message and the user context setup failure message in step 1 and step 2 are only examples, and may also be messages with other names, where the message with other names may be a message that does not need to be replied by the receiving node (in the protocol (e.g. TS36.423, TS38.423, TS38.473, etc.) is called a second type message (Class2 message)), or a message that needs to be replied by the receiving node (in the protocol (e.g. TS36.423, TS38.423, TS38.473) is called a first type message (Class 1 message), or if the message in step 1 does not need to be replied by the distribution unit, the message in step 2 may not be a feedback to the message sent by the central unit, but may be any other message, or if the message in step 1 needs to be replied by the distribution unit, the distribution unit replies to the message in step 1 in step 2

Fig. 13 is a sequence diagram illustrating a user connection request rejection method of the case illustrated in fig. 12, according to an embodiment of the present invention. As shown in fig. 13:

■ identification information of the user, e.g. C-RNTI

And 3, step 3: the central unit sends a user context setup request message to the distribution unit, which may contain at least one of the following information:

■ centralize the RRC messages generated by the elements. If the connection establishment request message is received in step 2, step 3 includes a connection establishment message and/or a connection establishment rejection message, if the connection restart request message is received in step 2, step 3 includes a connection restart message (or a connection establishment message) and/or a connection establishment rejection message, and if the connection reestablishment request message is received in step 2, step 3 includes a connection reestablishment message and/or a connection reestablishment rejection message. Optionally, the type of the RRC message is indicated in the user context setup request message (e.g., a connection setup message, a connection setup rejection message, a connection restart message, a connection reestablishment rejection message, etc.)

■ identification information of the user, e.g. C-RNTI

■ configuration information of Signaling Radio Bearer (Signaling Radio Bearer), such as identification of Signaling Radio Bearer, and/or configuration information of RLC layer, and/or configuration information of logical channel. The signaling radio bearer may be a first signaling radio bearer (SRB 1 in TS36.331 or TS38.331)

And 4, step 4: when the distribution unit does not accept (cannot or does not want) the connection request of the user, it sends the connection setup rejection message or the connection re-establishment rejection message received in step 3 to the user

And 5: the distribution unit sends a user context setup failure message to the central unit, the message indicating that the distribution unit does not accept (cannot or is unwilling) the connection request of the user, and the message may contain at least one of the following information:

subscriber identity information, such as CU UE F1AP ID, assigned by the central unit and used on the interface between the central unit and the distribution unit

■ identification information of the user, e.g. C-RNTI

The user context setup message and the user context setup failure message in step 3 and step 5 are only examples, and may also be messages with other names, where the message with other names may be a message that does not need to be replied by the receiving node (in the protocol (e.g. TS36.423, TS38.423, TS38.473, etc.) is called a second type message (Class2 message)), or a message that needs to be replied by the receiving node (in the protocol (e.g. TS36.423, TS38.423, TS38.473) is called a first type message (Class 1 message), or a message that does not need to be replied by the distribution unit in step 3, then the message that does not need to be replied by the distribution unit in step 5 may be not a feedback to the message sent by the central unit, but may be any other message, or a message that needs to be replied by the distribution unit in step 3, then the distribution unit replies to the message received in step 3 in step 5.

The method 3 comprises the following steps: refusing to establish a connection for a subscriber by a distribution unit sending a refusal indication message

Fig. 14 shows a schematic diagram of this case. The method defines a method for sending RRC messages between a distribution unit and a collection unit:

step 1: the distribution unit sends a non-user related message (such as Initial UL RRC message transfer) or a user related message (such as UL RRC message transfer) to the central unit, which may include at least one of the following information:

■ connection setup request message/connection restart request message/connection re-establishment request message received from user

■ identification information of the user, e.g. C-RNTI

Parameter configuration information related to MAC layer and physical layer

The resource allocation related information of the distribution unit may be in one information element (e.g. radioResourceConfigDedicated in 36.331) or in multiple information elements

■ indicating information about the user's access by the distribution unit, with which the concentration unit can determine whether the distribution unit can accept the user, which may be in the form of one of:

→ form 1: indicating access to the user using information on whether the resource allocation of the distribution unit is included:

■ if it contains the information related to the resource allocation of the above-mentioned distribution unit, it indicates that the distribution unit can accept the user's access, or it indicates that the distribution unit can accept the user's access due to some reasons, for example, the part of reasons is emergency, and/or highpriorityAccess, and/or mo-signaling, and the part of reasons is predefined or default, or indicated by indication information (the indication information indicates which reasons the distribution unit can accept the user's access), and it can be one or more of the reason information allowed to be included in any one or two or three of the three messages connection establishment request/connection restart request/connection reestablishment request;

■, if it does not contain the information related to the resource allocation of the distribution unit, it indicates that the distribution unit does not accept the user's Access, or indicates that the distribution unit does not accept the user's Access due to a part of reasons, for example, mt-Access or mo-Data or delaytorantaccess or mo-VoiceCall or reconfiguration failure or handoverFailure or other failure, the part of reasons being predefined or default or indicated by indication information (the indication information indicates which reasons the distribution unit does not accept the user's Access due to), which may be one or more of the reason information allowed to be included in any one or two or three of the three messages connection establishment request/connection restart request/connection re-establishment request;

→ form 2: indicating access to the user by using information on whether the resource allocation of the distribution unit is included and indication information (such as rejection indication information and congestion indication information) for rejecting user access:

■, if it contains the information related to the resource allocation of the distribution unit, it indicates that the distribution unit can accept the user's access

■, if it contains the information related to the resource allocation of the distribution unit and the indication information of rejecting the user access, it indicates that the distribution unit can accept the user access due to part of the reasons, which are predefined and can be one or more of the reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information related to user access are included, it indicates that the distribution unit can accept user access caused by authentication, high priority access, or mo-signaling, and user access caused by other reasons is not accepted by the distribution unit. Another embodiment is that, the indication information of access denial indicates that the distribution unit denies access to the user due to which reasons, and then, after receiving the connection establishment request/connection restart request/connection reestablishment request message, the central unit indicates that the distribution unit cannot accept the user if the reason information included in the message is the reason information indicated in the indication information of access denial. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the indication information of rejecting Access indicates that the distribution unit cannot accept the user if the Access reason of the user is mt-Access or mo-Data or delaytearanccess or delaytearanceaccess or mo-VoiceCall or recycling failure or handlerfailure or otherFailure.

■, if it contains neither the information relating to the resource allocation of the distribution unit, nor the indication information of refusing the user access, it means that the distribution unit can not accept the user access

→ form 3: and indicating access to the user by using information on whether the resource allocation of the distribution unit is included and indication information for allowing the user to access:

■, if it contains the above-mentioned information related to resource allocation of the distribution unit and the indication information of the allowed user access, it indicates that the distribution unit can accept the user access due to some reasons, which are predefined and can be one or more of the reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information for allowing the user access are included, it indicates that the distribution unit can accept the user access caused by authentication, high priority access, or mo-signaling, and the user access caused by other reasons is not accepted by the distribution unit. Another embodiment is that the indication information of allowed access indicates that the distribution unit allows the user access due to which reasons, and after receiving the connection establishment request/connection restart request/connection re-establishment request message, the central unit indicates that the distribution unit can accommodate the user if the reason information included in the message is the reason information indicated in the indication information of allowed access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user can be admitted by the distribution unit if the Access reason of the user is authentication or highcorrelation Access or mo-Signalling. If the information related to the resource allocation of the distribution unit is not included, and the indication information for allowing the user to access is not included, the distribution unit can not accept the access of the user

→ form 4: indicating the access of the distribution unit to the user by using the indication information of rejecting the access of the user:

■ contains an indication that the user is denied access, indicating that the distribution unit is not accepting the user. In another embodiment, if the indication information for rejecting the user access is included, it indicates that the distribution unit does not accept the access due to a part of reasons (e.g. one or more of the reason information allowed to be included in any one or two or three of the three messages of the connection establishment request, the connection restart request, and the connection reestablishment request), and the part of reasons is predefined; another embodiment is that the indication information of access rejection indicates that the distribution unit rejects the user access caused by which reasons, and then after receiving the connection establishment request/connection restart request/connection re-establishment request message, the central unit indicates that the distribution unit cannot accept the user if the reason information included in the message is the reason information indicated in the indication information of access rejection. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user Access rejection indication information indicates that the distribution unit cannot accept the user if the Access reason of the user is mt-Access or mo-Data or delaytearanceacess or delayteareacess or mo-VoiceCall or recycling failure or handlerfailure or otherFailure.

■, which contains no indication of denial of access to the user, indicates that the distribution unit may accept the user

→ form 5: indicating access of the distribution unit to the user by using indication information allowing user access:

■ contains the indication information of the user access, it indicates that the distribution unit accepts the user access; in another embodiment, if the indication information for allowing the user to access is included, it indicates that the distribution unit allows the access due to some reasons (e.g. one or more of the reason information allowed to be included in any one or two or three of the three messages of the connection establishment request, the connection restart request and the connection reestablishment request); another embodiment is that the indication information of allowed access indicates that the distribution unit allows the user access due to which reasons, and after receiving the connection establishment request/connection restart request/connection re-establishment request message, the central unit indicates that the distribution unit can accommodate the user if the reason information included in the message is the reason information indicated in the indication information of allowed access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user can be admitted by the distribution unit if the Access reason of the user is authentication or highcorrelation Access or mo-Signalling.

■, if it does not contain any indication that the user is allowed access, it indicates that the distribution unit does not accept the user's access

→ form 6: the distribution unit indicates the access of the distribution unit to this user by using whether the user identification information (e.g. DU UE F1AP ID) used on the interface between the concentration unit and the distribution unit is allocated:

■ if it contains the identification information, it indicates that the user's access is accepted

■ if it does not contain the identification information, it indicates that the user's access cannot be accepted

Step 2: the central unit sends non-user related messages (e.g., final downlink RRC message transfer messages) or user related messages (e.g., downlink RRC message transfer messages) to the distribution unit. If the final downlink RRC message transmission message is sent, the content of the message, the sending of the message, and the operations of the central unit and the distribution unit may refer to method 1 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message; if the sent message is a downlink RRC message transmission message, the content of the message, the sending of the message, and the operations of the central unit and the distribution unit may refer to method 2 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message;

the messages in step 1 and step 2 may be messages that do not require feedback from the receiving node, so step 1 and step 2 may be referred to as independent steps, that is, step 1 may become an independent step, as follows:

the distribution unit sends a non-user related message (such as Initial UL RRC message transfer) or a user related message (such as UL RRC message transfer) to the central unit, which may include at least one of the following information:

■ user ID information, such as C-RNTI, and/or user ID information assigned by the central unit for use at the interface between the central unit and the distribution units (e.g. CU UE F1AP ID), and user ID information assigned by the distribution units for use at the interface between the central unit and the distribution units (e.g. DU UE F1AP ID)

Parameter configuration information related to MAC layer and physical layer the resource allocation related information of the distribution unit may be within one information element (e.g. radioresourceconfigdetermined in 36.331) or within multiple information elements

■, if it contains the information related to the resource allocation of the distribution unit and the indication information of rejecting the user access, it indicates that the distribution unit can accept the user access due to part of the reasons, which are predefined and can be one or more of the reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information related to user access are included, it indicates that the distribution unit can accept user access caused by authentication, high priority access, or mo-signaling, and user access caused by other reasons is not accepted by the distribution unit. In another embodiment, the indication information of access denial indicates that the distribution unit denies access to the user due to which reasons, and after receiving the connection establishment request/connection restart request/connection reestablishment request message, the central unit indicates that the distribution unit cannot accept the user if the reason information included in the message is the reason information indicated in the indication information of access denial. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the indication information of rejecting Access indicates that the distribution unit cannot accept the user if the Access reason of the user is mt-Access or mo-Data or delaytearanccess or delaytearanceaccess or mo-VoiceCall or recycling failure or handlerfailure or otherFailure.

■, if it contains neither the information relating to the resource allocation of the distribution unit, nor the indication information of the user access rejection, it means that the distribution unit cannot accept the user's access

■, if it contains the above-mentioned information related to resource allocation of the distribution unit and the indication information of the allowed user access, it indicates that the distribution unit can accept the user access due to some reasons, which are predefined and can be one or more of the reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information for allowing the user access are included, it indicates that the distribution unit may accept the user access caused by authentication, high priority access, or mo-signaling, and the user access caused by other reasons is not accepted by the distribution unit. Another embodiment is that the indication information of allowed access indicates that the distribution unit allows the user access due to which reasons, and after receiving the connection establishment request/connection restart request/connection re-establishment request message, the central unit indicates that the distribution unit can admit the user if the reason information included in the message is the reason information indicated in the indication information of allowed access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user can be admitted by the distribution unit if the Access reason of the user is authentication or highcorrelation Access or mo-Signalling. If the information related to the resource allocation of the distribution unit is not included, and the indication information for allowing the user to access is not included, the distribution unit can not accept the access of the user

■ if it contains the identification information, it indicates that the user's access is admitted

After the central unit receives the message, the central unit determines that the distribution unit does not accept (cannot or is unwilling) the access subscriber. The subsequent operation of the concentration unit may be to generate a connection establishment rejection message/connection re-establishment rejection message and send it to the distribution unit.

Likewise, step 2 becomes an independent step as follows:

the central unit sends non-user related messages (e.g., final downlink RRC message transfer messages) or user related messages (e.g., downlink RRC message transfer messages) to the distribution unit. If the final downlink RRC message transmission message is sent, the content of the message, the sending of the message, and the operations of the central unit and the distribution unit may refer to method 1 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message; if the sent message is a downlink RRC message transmission message, the content of the message, the sending of the message, and the operations of the central unit and the distribution unit may refer to method 2 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message;

fig. 15 is a sequence diagram illustrating a user connection request rejection method of the case shown in fig. 14 according to an embodiment of the present invention. As shown in fig. 15:

step 2: the distribution unit sends a non-user related message (e.g. Initial UL RRC message transfer) or a user related message (UL RRC message transfer) to the central unit, where the message may include at least one of the following information:

■ user identification information, such as C-RNTI and/or user identification information assigned by the central unit for use at the interface between the central unit and the distribution units (e.g. CU UE F1AP ID) and/or user identification information assigned by the distribution units for use at the interface between the central unit and the distribution units (e.g. DU UE F1AP ID)

Parameters related to MAC layer and physical layerConfiguration information

form 1: indicating access to the user using information on whether the resource allocation of the distribution unit is included:

Form 4: indicating the access of the distribution unit to the user by using the indication information of rejecting the access of the user:

And step 3: and the centralized unit sends the final downlink RRC message transmission message or the downlink RRC message transmission message to the distribution unit. If the final downlink RRC message transmission message is sent, the sending of the message and the operations of the central unit and the distribution unit may refer to method 1 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message; if the sent message is a downlink RRC message transmission message, the sending of the message and the operation of the central unit and the distribution unit may refer to method 2 in the first case, where the message includes a connection establishment rejection message/a connection reestablishment rejection message;

and 4, step 4: the distribution unit sends the received connection establishment rejection message/connection reestablishment rejection message to the user

It should be noted that the order of steps shown in any of figures 6-15 above need not necessarily be performed in the order shown, but may be performed in any other suitable order, unless explicitly indicated or otherwise determined by the inherent logic of the steps. For example, the order of step 4 and step 5 shown in fig. 13 may be switched, or the two steps may be performed in parallel.

In one embodiment, the non-user related message (e.g. the final downlink RRC message transmission message) and the user related message (e.g. the downlink RRC message transmission message) are different in that one or both of the following information are included in the user related message:

When one of the above-mentioned information is included in the user-related message, the non-user-related message does not include the above-mentioned information, and when the two above-mentioned information are included in the user-related message, the non-user-related message may include one of the above-mentioned information.

A specific example of handling a user's request for access to the network based on an indication of the user's access by the distribution unit will be described in detail below.

Example a

Based on the above description (case 1 and case 2), a distribution unit may be defined to send a non-user related message (such as Initial UL RRC message transfer) or a user related message (such as UL RRC message transfer) to the central unit, as shown in fig. 15-1, where the message may include at least one of the following information:

identification information of the user sending the connection establishment request message/connection restart request message/connection re-establishment request message to the distribution unit, such as the C-RNTI, and/or user identification information allocated by the concentration unit for use on the interface between the concentration unit and the distribution unit (such as CU UE F1AP ID), and/or user identification information allocated by the distribution unit for use on the interface between the concentration unit and the distribution unit (DU UE F1AP ID)

Cell Identity information, such as pci (physical Cell Identity), and/or nci (NR Cell Identity), and/or NR CGI (NR Cell Global Identity), etc., indicating that the user is sending a message to the distribution unit in the Cell.

Information related to the resource allocation of the distribution unit, comprising at least one of the following information:

Parameter configuration information related to MAC layer and physical layer

Indication information of the distribution unit about the user access, with which the concentration unit can determine whether the distribution unit can accept the user, which may be in the form of one of the following:

form 2: indicating access to the user by using information on whether the resource allocation of the distribution unit is included and indication information (such as rejection indication information and congestion indication information) for rejecting user access:

■, if it contains the above-mentioned information related to resource allocation of the distribution unit and the indication information of refusing user access, it indicates that the distribution unit can accept user access due to part of reasons, which are predefined or default, and can be one or more of reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information for rejecting user access are included, it indicates that the distribution unit can accept user access caused by authentication, highpriorityAccess, and mo-signaling (that is, cause information included in the connection establishment request, the connection restart request, or the connection reestablishment request is authentication, highpriorityAccess, or mo-signaling), and user access caused by other causes is not accepted by the distribution unit. In another embodiment, the indication information for rejecting the user access indicates that the distribution unit rejects the user access caused by which reasons, and after receiving the connection establishment request/connection restart request/connection reestablishment request message, the central unit indicates that the distribution unit cannot accept the user if the reason information included in the message is the reason information indicated in the indication information for rejecting the user access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the indication information for rejecting the user Access indicates that the distribution unit cannot accept the user if the Access reason of the user is mt-Access or mo-Data or delaytorantaccess or mo-VoiceCall or recycling failure or handlerfailure or otherFailure.

■, if it contains the above-mentioned information related to resource allocation of the distribution unit and the indication information of the allowed user access, it indicates that the distribution unit can accept the user access due to some reasons, which are predefined or default, and can be one or more of the reason information allowed to be included in any one or two or three of the three messages of connection establishment request/connection restart request/connection re-establishment request. The above reason information can be found in TS36.331 and TS 38.331. For example, if the information related to resource allocation of the distribution unit and the indication information for allowing the user access are included, it indicates that the distribution unit can accept the user access caused by authentication, highpriorityAccess, and mo-signaling (that is, the reason information included in the connection establishment request, the connection restart request, or the connection reestablishment request is authentication, highpriorityAccess, or mo-signaling), and the user access caused by other reasons is not accepted by the distribution unit. Another embodiment is that the indication information for allowing the user to access indicates which reasons the distribution unit allows the user to access, and after receiving the connection establishment request/connection restart request/connection re-establishment request message, the concentration unit indicates that the distribution unit can accommodate the user if the reason information included in the message is the reason information indicated in the indication information for allowing the user to access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user can be admitted by the distribution unit if the Access reason of the user is authentication or highcorrelation Access or mo-Signalling.

■, if it contains neither the information related to the resource allocation of the distribution unit, nor the indication information allowing the user to access, it means that the distribution unit cannot accommodate the user's access

→ form 4: indicating the access of the distribution unit to the user by using the indication information of rejecting the user access:

■ contains an indication that the user is denied access, indicating that the distribution unit is not accepting the user. In another embodiment, if the indication information for rejecting the user access is included, it indicates that the distribution unit does not accept the access due to a part of reasons (e.g. one or more of the reason information allowed to be included in any one or two or three of the three messages of the connection establishment request, the connection restart request, and the connection reestablishment request), and the part of reasons is predefined or default; another embodiment is that the indication information for rejecting user access indicates that the distribution unit rejects user access caused by which reasons, and then after receiving the connection establishment request/connection restart request/connection reestablishment request message, the central unit indicates that the distribution unit cannot accept the user if the reason information included in the message is the reason information indicated in the indication information for rejecting access. For example, the reason information allowed to be included in the connection establishment request/connection restart request/connection reestablishment request is: the user Access rejection indication information indicates that if the Access reason of the user is mt-Access or mo-Data or delayttorantaccess or mo-VoiceCall or reconfigurating failure or handoverFailure, the distribution unit cannot accept the user.

The message may be the message sent by the distribution unit to the concentration unit in step 2 of fig. 7, or step 2 of fig. 9, or step 2 of fig. 11, or step 2 of fig. 13, or step 2 of fig. 15

After receiving the message, the central unit determines the next action according to the content of the message. Its possible actions include:

behavior 1: generating a connection establishment message or a connection restart message or a connection reestablishment message and sending the connection establishment message or the connection restart message or the connection reestablishment message to the distribution unit;

behavior 2: starting up the process of user context establishment to trigger the resource allocation of the distribution unit to the user

Behavior 3: and generating a connection rejection or connection reestablishment rejection message and sending the message to the distribution unit.

The process of the user establishing connection based on the information sent from the distribution unit to the central unit is shown in fig. 15-2

Step 1: user sends connection establishment request message to distribution unit

Step 2: the distribution unit sends an initial uplink RRC message to the central unit, where the information included in the message is as described in embodiment a above;

for the case of successful connection establishment:

step 3 a: the central unit determines that the user can be accessed according to the information received in the step 2, and sends a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises a connection establishment message

Step 4 a: the distribution unit sends the received connection establishment message to the user

And 5: the user sends a connection establishment completion message to the distribution unit

Step 6: the distribution unit sends an uplink RRC message transmission message to the central unit, where the message at least includes the connection establishment completion message received in step 5.

For the case of a connection establishment failure:

and step 3 b: the central unit determines not to accept the user access according to the information received in step 2, and sends a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises a connection rejection message

And 4 b: the distribution unit sends the received connection rejection message to the user.

The flow of the user restarting the connection based on the information sent by the distribution unit to the central unit is shown in fig. 15-3:

step 1: user sends connection restart request message to distribution unit

for the case that the connection restart is successful:

step 3 a: the concentration unit successfully obtains the context of the user and determines that the access of the user can be accepted according to the information received in step 2. If the central unit needs to further configure the data bearer of the user according to the context of the user, it sends a user context establishment request message to the distribution unit, where the message at least contains one of the following information:

■ cause information contained in the connection restart request message in step 1

■ data bearer related information, such as bearer identification, QoS related information of the bearer, etc. step 4 a: the distribution unit feeds back a user context setup request response message to the concentration unit to indicate resource allocation information of the distribution unit, which includes at least one of the following information:

Configuration information of a Data Radio Bearer (Data Radio Bearer), such as an identifier of the Data Radio Bearer, and/or configuration information of an RLC layer, and/or configuration information of a logical channel, etc.

Information of data radio bearers admitted by the distribution unit, e.g. identification of data radio bearers

Parameter configuration information related to MAC layer and physical layer

Step 5 a: the central unit sends a downlink RRC message transmission message to the distribution unit, which at least comprises a connection restart message

Step 6 a: the distribution unit sends the received connection restart message to the user

And 7: the user sends a connection restart completion message to the distribution unit

And 8: the distribution unit sends an uplink RRC message transmission message to the central unit, where the message at least includes the connection restart completion message received in step 7.

For the case of successful connection establishment:

and step 3 b: the central unit does not obtain the context of the user, but determines to accept the access of the user according to the information received in step 2, and sends a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises a connection establishment message

And 4 b: the distribution unit sends the received connection establishment message to the user

And step 5 b: the user sends a connection establishment completion message to the distribution unit

And 6 b: the distribution unit sends an uplink RRC message transmission message to the central unit, where the message at least includes the connection establishment completion message received in step 5 b.

For the case of a connection establishment failure:

and 3 c: the central unit determines not to accept the user's access according to the information received in step 2, and sends a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises a connection rejection message

And 4 c: the distribution unit sends the received connection rejection message to the user.

The flow of the connection reestablishment of the user based on the information sent from the distribution unit to the concentration unit is shown in fig. 15-4:

step 1: user sends connection reestablishment request message to distribution unit

for the case of successful connection re-establishment 1:

step 3 a: the centralized unit and the distribution unit both store the context of the user, and determine that the user can be accessed according to the information received in step 2, and send a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises one of the following information:

■ connection reestablishment message

■ is used to obtain the user context information, such as old user identification information (e.g. old gNB-DU UE F1AP ID) used by the user on the interface between the central unit and the distribution unit at the distribution unit side, old user identification information (e.g. old gNB-CUUE F1AP ID) used by the user on the interface between the central unit and the distribution unit at the central unit side, identification information (e.g. PCI, NCI, NR CGI) of the cell where the user is located before reconstruction, identification information (e.g. C-RNTI) used by the user before the reconstruction starts, and other information (e.g. shortMAC-I, refer to TS36.331, TS38.331)

■ updating indication information of the distribution unit resource allocation information:

the indication information may indicate that the resource allocation information (referred to as first resource allocation information) of the distribution unit in step 1 is updated to the resource allocation information (referred to as second resource allocation information) of the distribution unit about the user stored in the checked user context

Or the indication information may indicate that the distribution unit resource allocation information (referred to as second resource allocation information) about the user, which is stored in the searched user context, is updated to the distribution unit resource allocation information (referred to as first resource allocation information) included in step 1

The first resource allocation information or the second resource allocation information at least includes one of the following information:

configuration information of a Signaling Radio Bearer (Signaling Radio Bearer), such as an identifier of the Signaling Radio Bearer, and/or configuration information of an RLC layer, and/or configuration information of a logical channel, etc., the Signaling Radio Bearer may be a first Signaling Radio Bearer (SRB 1 in TS36.331 or TS38.331)

Configuration information of a Data Radio Bearer (Data Radio Bearer), such as identification of the Data Radio Bearer, and/or configuration information of an RLC layer, and/or configuration information of a logical channel, etc.

Parameter configuration information about MAC layer and physical layer

The information update updates only information common to the first resource allocation information and the second resource allocation information, and does not update information common to both information. The update indication information may be explicit, that is, an information element is used to indicate the indication information, or implicit, that is, the first resource allocation information is updated to the second resource allocation information by default or predefined, or the second resource allocation information is updated to the first resource allocation information

Step 4 a: the distribution unit sends the received connection reestablishment message to the user

Step 5 a: the user sends a connection reestablishment completion message to the distribution unit

Step 6 a: the distribution unit sends an uplink RRC message transmission message to the central unit, where the message at least includes the connection reestablishment complete message received in step 5 a.

For the case of successful connection re-establishment 2:

and step 3 b: only the concentration unit has the context of the user and determines that the user can be accessed according to the information received in step 2. If the central unit needs to further configure the data bearer of the user according to the context of the user, it sends a user context establishment request message to the distribution unit, where the message at least contains one of the following information:

■ cause information contained in the connection reestablishment request message in step 1

■ data bearer related information, such as bearer identification, QoS related information of the bearer, etc. step 4 b: the distribution unit feeds back a user context setup response message to the concentration unit, which optionally includes distribution unit resource allocation information, which includes at least one of the following information:

Parameter configuration information related to MAC layer and physical layer

And step 5 b: the central unit sends a downlink RRC message transmission message to the distribution unit, which at least comprises a connection reestablishment message

Step 6 b: the distribution unit sends the received connection reestablishment message to the user

And 7 b: the user sends a connection reestablishment completion message to the distribution unit

And step 8 b: the distribution unit sends an uplink RRC message transmission message to the central unit, where the message at least includes the connection reestablishment complete message received in step 7 b.

For the case of a connection establishment failure:

and step 3 c: the concentration unit has no user context, or determines not to accept user access according to the information received in step 2, and sends downlink RRC message transmission message to the distribution unit, wherein the message at least comprises connection reestablishment refusing message

And 4 c: the distribution unit sends the received connection reestablishment refusal message to the user.

In the above embodiment, the central unit may determine whether to start a procedure of user context establishment (see three defined behaviors) according to, for example, a "non-user-related message (such as Initial UL RRC message transfer) or a user-related message (such as UL RRC message transfer) sent by the distribution unit, so as to effectively reduce access delay of the user and reduce signaling overhead between the distribution unit and the central unit.

A specific example of processing in the case where the access reason is included in the access request of the user will be described in detail below.

Example b

According to the above description, a process for establishing a user context is defined between the distribution unit and the concentration unit, as shown in fig. 15-5, which includes the following steps:

step 1: the centralized unit sends a user context establishment request message to the distribution unit, wherein the message at least comprises one of the following information:

■ centralize the RRC messages generated by the unit. Such as a connection setup message and/or a connection reject message, or a connection restart message (or a connection setup message) and/or a connection reject message, or a connection re-establishment message and/or a connection re-establishment reject message.

■ identification information of the user, e.g. C-RNTI

■ Cell identification information, such as PCI (physical Cell Identity), NCI (NR Cell Identity), NR CGI (NR Cell Global Identity), etc., the Cell identification information of the Cell where the user is located

■ related information of data bearer, such as identification of bearer, QoS related information of bearer, etc

■ cause information for the user to establish or restart or re-establish a connection, the cause information is the cause information contained in the connection establishment request message/connection re-establishment request message sent by the user (the message is sent by the user to the distribution unit and forwarded by the distribution unit to the central unit), such as the cause information contained in the connection establishment request message (e.g. emergency occurrence, high priority Access, data needed to send mt-Access to the user, user initiated signaling mo-signaling, user initiated data sending mo-data, delay tolerable Access delay, user initiated voice mo-VoiceCall, etc.), or the cause information contained in the connection re-start request message (e.g. emergency occurrence, high priority Access, data needed to send user-mt, user initiated signaling, the method includes sending mo-data by user initiated data, accessing delaytileranteacess with tolerable time delay, voice mo-VoiceCall initiated by user, etc.), or reason information included in connection reestablishment request message (such as reconfiguration failure, handover failure, other failure other failures, etc.). The above reason information can be found in TS36.331 and TS 38.331.

The establishment is successful:

step 2 a: if the distribution unit can successfully establish the user context, the distribution unit feeds back a corresponding message for establishing the user context to the concentration unit, wherein the message optionally comprises the following information:

■ distributing unit resource allocation information including at least one of:

Parameter configuration information related to MAC layer and physical layer

Establishment failure

And step 2 b: if the distribution unit can not establish the user context, the distribution unit feeds back a user context establishment failure message to the concentration unit

This flow may be applied to step 3 and step 4 of fig. 11, or step 4 and step 5 of fig. 13, and also to the flows shown in fig. 15-6:

step 1: the user sends a connection establishment request or a connection restart request or a connection reestablishment request message to the distribution unit

Step 2: the distribution unit sends an initial uplink RRC message to the central unit, the message including the content as described in embodiment a

Situation of success

Step 3 a: the concentration unit sends a user context establishment request message to the distribution unit, the content of which is as described in step 1 of embodiment b

Step 4 a: the distribution unit sends a user context setup response message to the concentration unit, the message comprising the content as described in step 2a of embodiment b

Step 5 a: the central unit sends a connection establishment or connection restart or connection re-establishment message to the distribution unit

Step 6 a: the distribution unit sends a connection setup or connection restart or connection re-establishment message to the user

And 7: the user sends a connection establishment completion message, a connection restart completion message or a connection reestablishment completion message to the distribution unit;

and 8: the distribution unit sends an uplink RRC message transmission message to the central unit, which at least includes the connection setup complete or connection restart complete or connection reestablishment complete message received in step 7.

Case of failure:

and step 3 b: the concentration unit sends a user context establishment request message to the distribution unit, wherein the content included in the message is the content described in step 1 of embodiment b;

and 4 b: the distribution unit sends a user context establishment failure message to the concentration unit, the content of which is as described in step 2b of embodiment b

And step 5 b: the central unit sends a downlink RRC message transmission message to the distribution unit, wherein the message at least comprises a connection establishment failure or connection reconstruction failure message;

step 6 b: the distribution unit sends the connection establishment failure or connection reestablishment failure message received in step 5b to the user.

In the above scheme, the distribution unit may be assisted to effectively perform access control for the user by processing the user access request based on the intention of the user to access the network (for example, some services are relatively urgent services or transmission of some signaling, such services have low bandwidth requirements, and in the case that the capacity of the distribution unit is limited, the access of such user may also be allowed).

Fig. 16 schematically shows a block diagram of a base station 1600 according to an embodiment of the present disclosure. The base station 1600 includes a processor 1610, e.g., a Digital Signal Processor (DSP). Processor 1610 may be a single device or multiple devices for performing different acts according to embodiments of the invention. Base station 1600 may also include input/output (I/O) devices 1630 for receiving signals from, or transmitting signals to, other entities.

Further, the base station 1600 includes a memory 1620, the memory 1620 may have the form: non-volatile or volatile memory, such as electrically erasable programmable read-only memory (EEPROM), flash memory, and the like. Memory 1620 stores computer readable instructions that, when executed by processor 1610, cause the processor to perform a method according to an embodiment of the invention.

Those skilled in the art will appreciate that embodiments of the present invention include apparatuses for performing one or more of the operations described in the present application. These devices may be specially designed and manufactured for the required purposes, or they may comprise known devices in general-purpose computers. These devices have stored therein computer programs that are selectively activated or reconfigured. Such a computer program may be stored in a device (e.g., computer) readable medium, including, but not limited to, any type of disk including floppy disks, hard disks, optical disks, CD-ROMs, and magnetic-optical disks, ROMs (Read-Only memories), RAMs (Random Access memories), EPROMs (Erasable Programmable Read-Only memories), EEPROMs (Electrically Erasable Programmable Read-Only memories), flash memories, magnetic cards, or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a bus. That is, a readable medium includes any medium that stores or transmits information in a form readable by a device (e.g., a computer).

It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions may be implemented by a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the features specified in the block or blocks of the block diagrams and/or flowchart illustrations of the present disclosure.

Those of skill in the art will appreciate that various operations, methods, steps in the processes, acts, or solutions discussed in the present application may be alternated, modified, combined, or deleted. Further, various operations, methods, steps in the flows, which have been discussed in the present disclosure, may also be alternated, modified, rearranged, split, combined, or deleted. Further, steps, measures, schemes in the various operations, methods, procedures disclosed in the prior art and the present invention can also be alternated, changed, rearranged, decomposed, combined, or deleted.

The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method performed by a central unit, CU, node, the method comprising:

receiving an initial uplink, UL, radio resource control, RRC, message from a distribution unit, DU, node, the initial UL RRC message comprising information of a cell radio network temporary identifier, C-RNTI, associated with a user equipment, UE; and

determining that the DU node cannot provide service for the UE and rejecting the UE, in case the initial UL RRC message does not include information related to resource allocation of the DU node.

2. The method of claim 1, wherein the initial UL RRC message further comprises: information of said DU node relating to UE F1 application identification UE F1APID, and information relating to a new radio cell global identifier NR CGI.

3. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein the CU nodes are associated with RRC, packet data Convergence protocol PDCP, and service data Adaptation protocol SDAP, and the DU nodes are associated with a radio Link control protocol RLC layer, a Medium Access control MAC layer, and a physical PHY layer;

and/or

The information related to resource allocation of the DU node includes at least one of:

configuration information of the first signaling radio bearer SRB 1;

configuration information of the RLC layer;

configuration information of the MAC layer; and

configuration information of the PHY layer.

4. The method of claim 1, further comprising:

determining that the DU node is capable of providing a service for the UE in a case that the initial UL RRC message includes information related to resource allocation of the DU node.

5. The method of claim 1, wherein the initial UL RRC message is received based on non-UE associated signaling, an

Wherein the initial UL RRC message is received via an F1 interface.

6. A method performed by a distribution unit, DU, node, the method comprising:

generating an initial Uplink (UL) Radio Resource Control (RRC) message by not including information related to resource allocation of the DU node in the initial UL RRC message based on the determination that the DU node cannot provide service for the User Equipment (UE); and

transmitting the initial UL RRC message to a Central Unit (CU) node, the initial UL RRC message including information of a cell radio network temporary identifier (C-RNTI) associated with the UE.

7. The method of claim 6, wherein the initial UL RRC message further comprises: information of the DU node relating to the UE F1 application identity UE F1APID, and information relating to the new radio cell global identifier NR CGI.

8. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

and/or

configuration information of the first signaling radio bearer SRB 1;

configuration information of the RLC layer;

configuration information of the MAC layer; and

configuration information of PHY layer, and/or

Wherein the initial UL RRC message is received based on non-UE associated signaling and the initial UL RRC message is received via an F1 interface.

9. The method of claim 6, further comprising:

generating the initial UL RRC message by including information related to resource allocation of the DU node in the initial UL RRC message based on the determination that the DU node is capable of serving the user equipment UE.

10. An apparatus for network access, comprising:

at least one processor; and the number of the first and second groups,

the memory stores instructions executable by the one processor to cause the at least one processor to perform the method of any one of claims 1-5 or 6-9.

11. The apparatus of claim 10, wherein the apparatus is a centralized unit in a base station when the at least one processor performs the method of any of claims 1-5, and the apparatus is a distributed unit in a base station when the at least one processor performs the method of any of claims 6-9.

12. A computer-readable storage medium having stored thereon executable instructions that, when executed by a processor, cause the processor to perform the method of any of claims 1-5 or 6-9.