CN111556480A

CN111556480A - Method and system for sharing distributed network elements by multiple operators

Info

Publication number: CN111556480A
Application number: CN202010078459.9A
Authority: CN
Inventors: 王俊; 刘斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-01-31
Filing date: 2020-02-03
Publication date: 2020-08-18
Anticipated expiration: 2040-02-03
Also published as: CN111556480B

Abstract

The invention provides a method and a system for sharing a distributed network unit by a plurality of operators, wherein each operator in the plurality of operators is configured with a corresponding centralized network unit, and UE is connected to a core network through the distributed network unit and the centralized network unit, and the method comprises the following steps: broadcasting, by the distributed network element, a PLMN ID list of the plurality of operators; and determining, by the distributed network element, a PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE. The invention provides high-speed and high-capacity service for the UE with less investment and can realize airplane communication of seamless switching between the ground and the airplane.

Description

Method and system for sharing distributed network elements by multiple operators

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method and a system for sharing a distributed network element by multiple operators.

Background

Currently, there are two main implementation ways for aircraft communication: the Ka/Ku frequency band satellite is switched by airborne communication equipment and then is connected to a ground communication network; or the ground-air data transmission is realized by using 3G or 4G technology through connecting the airborne communication equipment with the ATG base station on the ground. The two methods have the common problems of high cost, low access data rate and large time delay.

Disclosure of Invention

To address the problems in the prior art, according to one embodiment of the present invention, a method for sharing a distributed network element by multiple operators is provided. Wherein each of the plurality of operators is configured with a corresponding centralized network element through which the UE connects to a core network, the method comprising: broadcasting, by the distributed network element, a PLMN ID list of the plurality of operators; and determining, by the distributed network element, a PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE.

In the above method, determining, by the distributed network element, a PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE may include: acquiring, by the distributed network element, information of a PLMN selected by the UE from an RRC setup request message or a random access message from the UE, thereby determining an operator selected by the UE; and sending, by the distributed network element, an initial UL RRC messaging message to a centralized network element corresponding to the operator selected by the UE.

In the above method, the PLMN information may be a PLMN ID or an index of a PLMN ID in the PLMN ID list.

The method may further include broadcasting, by the distributed network element, a PRACH partition configuration corresponding to a PLMN. Wherein determining, by the distributed network element, the PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE may include: and the distributed network unit determines the PLMN selected by the UE according to the PRACH partition of the random access message sent by the UE so as to determine the operator selected by the UE, and sends an initial UL RRC message transmission message to a centralized network unit corresponding to the operator selected by the UE.

In the above method, determining, by the distributed network element, a PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE may include: acquiring, by the distributed network element, information of a PLMN selected by the UE from an RRC setup complete message from the UE, thereby determining an operator selected by the UE; sending, by the distributed network element, an initial UL RRC messaging message to a target centralized network element, wherein the target centralized network element is a centralized network element corresponding to an operator selected by the UE; sending, by the target centralized network element, a DL RRC messaging message and SRB1 configuration to the distributed network element; sending, by the distributed network element, a UE context release message to a source centralized network element with which a connection is established in an RRC establishment phase; and correcting, by the distributed network element, the SRB1 configuration in an RRC reconfiguration message.

The above method may further comprise: when receiving the RRC establishment request message from the UE, the distributed network unit searches for a centralized network unit corresponding to an operator of the PLMN selected by the UE, and if not found, rejects the RRC establishment request of the UE and does not broadcast the PLMN ID of the operator any more.

The above method may further comprise: starting a timer by a distributed network element when all UEs connected to a centralized network element corresponding to an operator disconnect from the distributed network element; disconnecting, by the distributed network element, the centralized network element corresponding to the operator after the timer expires.

In the above method, the distributed network unit may be a DU of a 5G base station or an IAB node; and the centralized network element may be a CU of a 5G base station or a home IAB base station.

In the above method, the distributed network unit and the centralized network unit are connected through an F1 interface.

In the above method, the UE is located on an airplane, the distributed network element is deployed on the airplane, and the centralized network element is deployed on the ground.

There is also provided, in accordance with an embodiment of the present invention, a system for sharing a distributed network element by a plurality of operators, including: a distributed network unit, configured to broadcast PLMN ID lists of the multiple operators, determine a PLMN selected by the UE, and connect the UE to a centralized network unit corresponding to an operator of the PLMN selected by the UE, so that the UE is connected to a core network through the distributed network unit and the centralized network unit; and a centralized network unit corresponding to each of the plurality of operators.

The embodiment of the invention provides the following beneficial effects:

the method provides high-speed and high-capacity services for the UE with less investment, and realizes airplane communication of seamless switching between the ground and the airplane. In addition to aircraft communications, the present invention is also applicable to user communications in other vehicles (e.g., ordinary trains, motor cars, high-speed rails, etc.) as well as user communications in non-moving spaces (e.g., buildings, etc.). In other words, the present invention is applicable to any network structure of non-integrated base stations (i.e. RAN between CU and multiple DUs).

Drawings

Example embodiments will be described in detail with reference to the accompanying drawings, which are intended to depict example embodiments and should not be construed as limiting the intended scope of the claims. The drawings are not to be considered as drawn to scale unless explicitly indicated.

Fig. 1 schematically shows a block diagram of a 5G distributed RAN architecture according to one embodiment of the invention;

FIG. 2 schematically shows a block diagram of a system for operator specific CU sharing DUs for implementing airplane communication according to an embodiment of the present invention;

FIG. 3 schematically shows a schematic diagram of a system for operator specific CU DU sharing for aircraft communication implementation according to one embodiment of the present invention;

fig. 4 schematically shows a flow chart of a UE initial access procedure in a 5G distributed RAN architecture according to an embodiment of the present invention;

FIG. 5 schematically shows a flow diagram of a method of sharing a distributed network element by multiple operators according to one embodiment of the invention;

FIG. 6 schematically illustrates a block diagram of an IAB architecture in accordance with one embodiment of the present invention;

fig. 7 schematically shows a schematic diagram of a system for sharing IAB nodes by operator-specific dgnbs for aircraft communication according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by embodiments with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Similar to airplane communication, there is subway communication, in which an antenna or a Remote Radio Unit (RRU) is pre-installed in a current subway and some buildings, and an operator (MNO, such as china unicom, china mobile, china telecom, etc.) uses the antenna or the RRU by paying a fee to an owner of the subway or the building. Seamless access services are provided to user terminals (UEs) within a subway or building by sharing these antennas or RRUs by the base stations of all operators. The antenna or RRU is usually connected to a base station of an operator through an optical fiber, and the optical fiber has the characteristics of large capacity, high speed and the like, so that the communication quality is high. On the basis, the scheme that the operator shares the network unit can be applied to aircraft communication to realize seamless switching aircraft communication. However, the above-mentioned solution in which operators share antennas/RRUs of subways/buildings cannot be directly applied to aircraft communication, which generally requires connection to be established through an air interface, and if the capacity is too small, there may be a problem that the antennas or the RRUs cannot be directly connected, thereby affecting the aircraft communication.

To implement airplane communication, a distributed network unit may be deployed on an airplane and respective centralized network units of operators may be deployed on the ground, the distributed network units on the airplane are shared by a plurality of centralized network units on the ground (in other words, the distributed network units on the airplane are shared by a plurality of operators), and the UE on the airplane is connected to the core network through the distributed network units and the centralized network units of a particular operator, thereby implementing airplane communication for seamless handover between the ground and the airplane. The distributed Network unit broadcasts, to the UE on the airplane, an identification list (hereinafter, referred to as PLMN ID list) of Public Land Mobile networks (PLMNs for short) of all operators supported by the distributed Network unit; the UE selects a PLMN from the received PLMN ID list and passes information of the selected PLMN to the distributed network element, so that the distributed network element can thereby determine the PLMN selected by the UE, i.e. determine the operator of the PLMN; the distributed network element may then connect the UE to the operator-specific (corresponding) centralized network element, thereby connecting to the core network for airplane communication.

According to one embodiment of the invention, a method of sharing a distributed network element by a plurality of operators is provided. With reference to the 5G Distributed RAN architecture shown in fig. 1, a Distributed Unit (DU) of a 5G base station (see gb-DU in fig. 1) is used as a Distributed network Unit deployed on an airplane, a Centralized Unit (CU) of the 5G base station is used as a centralized network Unit deployed on the ground, a specific CU is configured for each operator, and the DU and the CU are connected by using an F1 interface (see 3GPP TS 38.473). Fig. 2-3 schematically illustrate a deployed system in which User Plane Functions (UPF) connected to the internet and the operator service network can be integrated into the CU, and network slicing functions (see 3GPP TS23.501) are provided mainly by the CU and the core network.

In summary, the method for sharing a distributed network unit by a plurality of operators of the embodiment includes: broadcasting, by the DU, PLMN ID lists of all operators supported by the DU, determining a PLMN selected by the UE, and connecting the UE to a CU corresponding to the operator of the PLMN. For the 5G distributed RAN architecture, section 8.1 of 3GPP TS 38.401 defines an initial access procedure of the UE, that is, a procedure of establishing an RRC connection between the UE and the 5G base station (gNB) in an RRC _ IDLE state, and fig. 4 schematically illustrates an overall initial access procedure of the UE, in which the UE establishes a connection with the DU (see gNB-DU in fig. 4) first and then establishes a connection with the CU (see gNB-CU in fig. 4). To implement the sharing of DUs by multiple operators and further implement airplane communication based on the INITIAL access procedure shown in fig. 4, the DU needs to determine the PLMN selected by the UE, i.e. the CU to be connected, before sending an INITIAL UL RRC message transmission (see step 2 in fig. 4, i.e. 2.INITIAL UL RRCMESSAGE TRANSFER) message to the CU. In view of this, referring to fig. 5, the method for sharing a distributed network element by multiple operators of the present embodiment may include the following steps:

step s11. the DU broadcasts system information, wherein the system information includes a PLMN ID list of operators supported by the DU.

Specifically, system information is broadcast by a DU deployed onboard the aircraft to UEs onboard the aircraft. The system information is used to provide main information of the wireless side, including a small amount of NAS and core network information (such as, but not limited to, system bandwidth, configuration and system frame number of physical channel, cell access and reselection related information, etc.), so that the UE can establish a radio connection and use various functions provided by the network. In addition, the system information further includes a PLMN ID list of operators supported by the DU, and the PLMN ID list is formed by sequentially arranging PLMN IDs of all operators supported by the DU.

Step s12. the ue selects a PLMN from the received PLMN ID list, adds information of the selected PLMN to an RRC Setup Request (see 1.RRC Setup Request in fig. 4) message and transmits the RRC Setup Request message to the DU.

As known from step S12, the embodiment needs to be further modified based on the 3GPP standard, that is, information of the PLMN selected by the UE is added in the RRC setup request message. In addition, referring to fig. 4, the UE initiates a random Access procedure before sending the RRC setup request message, wherein resources for sending the RRC setup request message are allocated to the UE in a random Access Response (see b.random Access Response in fig. 4) message. Generally, the resources allocated to the RRC setup request message are small, and there are no extra bits to transmit more information (e.g., information of the PLMN selected by the UE). In this regard, the DU may be configured to allocate more resources to the UE in the random access response message to enable the UE to send a larger RRC setup request message with information of the PLMN selected by the UE.

In one embodiment of the present invention, the information of the PLMN added to the RRC setup request message may be a PLMN ID of the PLMN selected by the UE.

In a preferred embodiment of the present invention, in order to save the number of bits of Uplink (UL) transmission, the information added to the PLMN in the RRC establishment request message may be an index of the PLMN ID selected by the UE in the PLMN ID list. For example, if the PLMN ID selected by the UE is the first PLMN ID in the PLMN ID list broadcasted by the DU, the information of the PLMN added to the RRC establishment request message may be 1; if the PLMN ID selected by the UE is the second PLMN ID in the PLMN ID list, the information added to the PLMN in the RRC establishment request message may be 2; and so on.

Step s13. the du acquires information of the PLMN selected by the UE from the RRC setup request message from the UE, determines an operator of the PLMN selected by the UE, and sends an INITIAL UL RRC message transmission (see 2.INITIAL UL RRC MESSAGE TRANSFER in fig. 4) message to a CU corresponding to the operator selected by the UE through an F1 interface, so as to complete an access procedure of the UE.

In the above embodiments, the 5G distributed RAN architecture is utilized to save deployment cost; the DU is shared by a plurality of operator-specific CUs to realize airplane communication, so that users on the airplane can seamlessly enjoy 5G service; the F1 interface is used between the DU and CU to provide high-rate, high-capacity communication services to the users onboard the aircraft. In addition to aircraft communications, the method of sharing a distributed network element by multiple operators in the above embodiments is also applicable to communications for users in other vehicles as well as communications for users in non-moving spaces. In addition, the F1 interface between the DU and the CU may be carried over various links, for example, over wired links, thereby enabling high-rate, high-capacity data transmission.

The above embodiment is to transmit the information of the PLMN selected by the UE through an RRC setup request message. Referring to fig. 4, before the DU sends an initial UL RRC message transmission (see step 2 in fig. 4) message to the CU, information of the PLMN selected by the UE may also be delivered in the UE random access procedure. Based on this, according to an embodiment of the present invention, there is also provided a method for sharing a distributed network element by a plurality of operators, the method being applicable to a random access procedure defined in 3GPP release 15, i.e., 4-step RACH, the method including the steps of:

step s21. the DU broadcasts system information, where the system information includes a PLMN ID list of operators supported by the DU. In addition, the system information is further extended, that is, the system information defines the resources of a Physical Random Access Channel (PRACH) specific to the PLMN. For example, PLMN 1 is allocated PRACH partition 1(PRACH 1), PLMN 2 is allocated PRACH partition 2(PRACH 2), and so on.

Step s22. the ue selects a PLMN from the received PLMN ID list, and transmits information of its selected PLMN to the DU through Random Access (see a. prach: Random Access in fig. 4).

Specifically, the UE acquires PRACH configuration corresponding to the selected PLMN from the system information, that is, acquires a specific PRACH partition allocated to the selected PLMN; the UE then transmits a random access message via this particular PRACH partition, whereby the DU may determine the UE-selected PLMN according to the PRACH partition in which the UE transmits the random access message. For example, if the UE selects PLMN 1, the random access message may be sent via PRACH partition PRACH 1 allocated to PLMN 1; if the UE selects PLMN 2, the random access message may be sent via PRACH partition PRACH 2 allocated to PLMN 2, as follows:

PLMN 1: PRACH 1 (preamble set 1, time/frequency resource 1.)

PLMN 2: PRACH 2 (preamble group 2, time/frequency resource 2.)

PLMN 3: PRACH 3 (preamble group 3, time/frequency resource 3.)

……

And S23. the DU acquires the information of the PLMN selected by the UE according to the random access of the UE, thereby determining the operator of the PLMN selected by the UE.

As described above, the DU may determine, according to the PRACH partition where the UE sends the Random Access message (see, a.prach: Random Access in fig. 4), the PLMN corresponding to the PRACH partition, that is, obtain the PLMN selected by the UE.

The DU returns a random Access Response (see b.random Access Response in fig. 4) message to the UE after receiving the random Access message from the UE. Subsequently, an RRC setup request message is sent by the UE to the DU (see step 1 in fig. 4).

Step s24. after receiving the RRC setup request message from the UE, the DU sends an INITIAL UL RRC message transmission (see 2.INITIAL UL RRC MESSAGE TRANSFER in fig. 4) message to the CU corresponding to the operator selected by the UE through the F1 interface, so as to complete the access procedure of the UE.

There is also provided, in accordance with an embodiment of the present invention, a method for sharing a distributed network element by a plurality of operators, the method being applicable to a random access procedure defined in 3GPP release 16, i.e., a two-step RACH, the method including the steps of:

step s31. the DU broadcasts system information, where the system information includes a PLMN ID list of operators supported by the DU.

Step s32. the ue selects a PLMN from the received PLMN ID list, directly adds information of its selected PLMN to a Random Access (see a. prach: Random Access in fig. 4) message, and transmits the Random Access message to the DU.

The information added to the PLMN in the random access message may be a PLMN ID, or may be an index of the selected PLMN ID in a PLMN ID list.

Step s33. the du acquires information of the PLMN selected by the UE from the random access message from the UE, thereby determining the operator of the PLMN selected by the UE.

After receiving the random access message from the UE, the DU returns a random access response message to the UE; subsequently, an RRC setup request message is sent by the UE to the DU.

Step s34. after receiving the RRC setup request message from the UE, the DU sends an INITIAL UL RRC message transmission (see 2.INITIAL UL RRC MESSAGE TRANSFER in fig. 4) message to the CU corresponding to the operator selected by the UE through the F1 interface, so as to complete the access procedure of the UE.

The above embodiments all need to be modified based on the 3GPP standard, and need to extend system information, even if the release after 3GPP release 16 accepts the solution described in the above embodiments, the case that the UE does not support PRACH partition still needs to be considered. For a UE that does not support PRACH partition, according to an embodiment of the present invention, there is also provided a method for sharing a distributed network element by multiple operators. Wherein, after the UE sends an RRC Setup Complete (see 5.RRC Setup Complete in fig. 4) message to the DU, the DU redirects the UE to the CU corresponding to the operator of the PLMN selected by the UE. It should be noted that, the current 3GPP standard has adopted the UE redirection procedure, and the method for sharing distributed network elements by multiple operators includes the following steps:

step s41.DU broadcasts system information, wherein the system information includes PLMN ID list of operators supported by the DU.

Step s42. the ue selects a PLMN from the received PLMN ID list, adds information of the selected PLMN to an RRC Setup Complete (see 5.RRC Setup Complete in fig. 4) message, and transmits the RRC Setup Complete message to the DU. The information of the PLMN added to the RRC setup complete message may be a PLMN ID, or may be an index of the selected PLMN ID in a PLMN ID list.

The UE may select a PLMN from the PLMN ID list based on rules defined in GPP TS 23.122, that is, select an operator; the information of the selected PLMN is then added to the RRC setup complete message and the RRC setup complete message is transmitted to the DU. It should be understood that the DU directs the UE to one CU before sending the RRC setup complete message (referred to as source CU, see steps 1-4 in fig. 4).

And S43. the DU acquires the information of the PLMN selected by the UE from the RRC establishment completion message from the UE, determines the operator of the PLMN selected by the UE, and redirects the UE to the CU corresponding to the operator selected by the UE through an F1 interface. In one embodiment, step S43 includes the following sub-steps:

and a substep S431. the DU acquires the information of the PLMN selected by the UE from the RRC establishment completion message from the UE so as to determine the operator of the PLMN selected by the UE, and sends an INITIAL UL RRC message transmission (INITIAL UL RRCMESSAGE TRANSFER) message to a CU (central office) corresponding to the operator selected by the UE, namely a target CU (central office) through an F1 interface. Wherein the initial ULRRC messaging message includes a low-level configuration of the UE.

Substep s432. a DL RRC messaging (DL RRC MESSAGETRANSFER) message is sent by the target CU to the DU over the F1 interface. Where the DL RRC messaging message sends the lower layer configuration back to the DU, and the target CU sends its SRB1 configuration to the DU.

The SRB1 configuration for different operators should generally be the same, but differ in the setting of a time reordering timer, which is valid only if the RLC layer cannot correct transmission failures in time. In case the SRB1 configurations of different operators are different, the UE should still use the old SRB1 configuration received in the RRC Setup (see 4.RRC Setup in fig. 4) message for a short time. Subsequently, the DU may correct the SRB1 configuration in an RRC Reconfiguration (see 15.RRC Reconfiguration in fig. 4) message, where the operator specific CUs sharing the DU should resend their SRB1 configuration.

Sub-step s433. a UE Context Release (UE Context Release) message is sent by the DU to the source CU over the F1 interface to Release the source CU.

The above-described embodiment uses the DU of the 5G base station as a distributed network unit deployed on an airplane and uses the CU of the 5G base station as a centralized network unit deployed on the ground. In other cases, it is also possible to use distributed network units different from DUs and to use centralized network units different from CUs. Based on this, according to one embodiment of the present invention, there is also provided a method of sharing a distributed network element by a plurality of operators. In which, an Integrated Access and Backhaul (IAB) architecture (see 3GPP TR 38.874) shown in fig. 6 is utilized, an IAB node is used as a distributed network unit on an airplane, and a home IAB base station (IAB Donor, in fig. 7, a DgNB) is used as a centralized network unit on the ground, where the IAB node includes a DU and a user Terminal (Mobile Terminal, MT), and the home IAB base station (DgNB) includes a DU and a CU. A specific home IAB base station (DgNB) is configured for each operator, and DUs in the IAB nodes and CUs of the home IAB base station (DgNB) employ an F1 interface, which F1 interface may be carried over a 5G air interface. Fig. 7 schematically illustrates a deployed system, since 3GPP release 16 has defined the protocols, functions and flows of the interfaces in the IAB architecture (where it is specified how the F1 interface is carried over the 5G air interface), better coordination and QoS support is provided between the UE air interface and the forward air interface compared to the above embodiments with DUs as distributed network elements and CUs as centralized network elements.

The various steps of a method for sharing a distributed network element (IAB node) by multiple operators is described below with reference to fig. 7:

step S51, the IAB node broadcasts system information, wherein the system information comprises a PLMNID list of operators supported by the IAB node.

Specifically, an IAB node deployed on an airplane may have one element (not shown in fig. 7) shared by multiple operators that broadcasts system information to UEs on the airplane, including a list of PLMN IDs of operators supported by the IAB node.

And S52, the IAB node dynamically establishes connection with the DgNB corresponding to the operator selected by the UE according to the information of the PLMN selected by the UE, namely, connection is established between the DU in the IAB node and the CU in the selected DgNB.

The process of selecting the PLMN by the UE may refer to the above, and is not described herein again. In one embodiment of the present invention, step S52 may include:

upon receiving an RRC Setup Request (RRC Setup Request) message from the UE, the IAB node attempts to establish a connection with a DgNB specific to an operator selected by the UE if it has not already established a connection with the DgNB corresponding to the operator. The IAB node searches for a DgNB corresponding to a suitable operator, establishes a connection if found, rejects the RRC establishment request of the UE if not found, and removes the PLMN ID of the operator from the system information broadcasted by the IAB node (i.e., does not broadcast the PLMN ID of the operator any more).

Step S53, when all the UEs connected to the DgNB corresponding to a certain operator are disconnected from the IAB node, the IAB node keeps the connection with the DgNB for the UE of the operator for a certain time, and then disconnects the connection with the DgNB.

Specifically, when all UEs connected to the DgNB corresponding to a certain operator disconnect from the IAB node, the IAB node starts a timer; after the timer expires, the IAB node disconnects the DgNB corresponding to that operator.

In the above embodiment, the IAB node deployed on the airplane has one unit shared by multiple operators. However, those skilled in the art will appreciate that in other embodiments, an IAB node deployed on an airplane may have multiple operator-specific elements, each element supporting only its corresponding operator.

It should be noted that some example methods are described as a flow of steps, and although the flow represents operations as being performed sequentially, it should be understood that many of the operations may be performed in parallel, concurrently, or synchronously. In addition, the order of the operations may be rearranged. A process may terminate when an operation is completed, but may have additional steps not included in the figure or embodiment.

The above-described methods may be implemented by hardware, software, firmware, middleware, pseudocode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or pseudo code, the program code or code segments to perform the tasks may be stored in a computer readable medium such as a storage medium, and a processor may perform the tasks.

It should be appreciated that the software-implemented exemplary embodiment is typically encoded on some form of program storage medium or implemented over some type of transmission medium. The program storage medium may be any non-transitory storage medium such as a magnetic disk (e.g., a floppy disk or a hard drive) or an optical disk (e.g., a compact disk read only memory or "CD ROM"), and may be read only or random access. Similarly, the transmission medium may be twisted wire pairs, coaxial cable, optical fiber, or some other suitable transmission medium known to the art.

Although the present invention has been described by way of preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the present invention.

Claims

1. A method of sharing a distributed network element by a plurality of operators, wherein each operator of the plurality of operators is configured with a corresponding centralized network element through which a UE connects to a core network, the method comprising:

broadcasting, by the distributed network element, a list of PLMNIDs for the plurality of operators; and

determining, by the distributed network element, a PLMN selected by the UE, and connecting the UE to a centralized network element corresponding to an operator of the PLMN selected by the UE.

2. The method of claim 1, wherein determining, by the distributed network element, a UE-selected PLMN, and connecting the UE to an operator-corresponding centralized network element of the UE-selected PLMN comprises:

acquiring, by the distributed network element, information of a PLMN selected by the UE from an RRC setup request message or a random access message from the UE, thereby determining an operator selected by the UE; and

sending, by the distributed network element, an initial UL RRC messaging message to a centralized network element corresponding to an operator selected by the UE.

3. The method of claim 2, wherein the information of the PLMN is a PLMN ID or an index of a PLMN ID in the PLMN ID list.

4. The method of claim 1, wherein the method further comprises broadcasting, by the distributed network element, a PRACH partition configuration corresponding to a PLMN; and

determining, by the distributed network element, a UE-selected PLMN, and connecting the UE to a centralized network element corresponding to an operator of the UE-selected PLMN comprises:

determining, by the distributed network element, a PLMN selected by the UE according to a PRACH partition in which the UE sends a random access message, thereby determining an operator selected by the UE,

5. The method of claim 1, wherein determining, by the distributed network element, a UE-selected PLMN, and connecting the UE to an operator-corresponding centralized network element of the UE-selected PLMN comprises:

acquiring, by the distributed network element, information of a PLMN selected by the UE from an RRC setup complete message from the UE, thereby determining an operator selected by the UE;

sending, by the distributed network element, an initial UL RRC messaging message to a target centralized network element, wherein the target centralized network element is a centralized network element corresponding to an operator selected by the UE;

sending, by the target centralized network element, a DL RRC messaging message and SRB1 configuration to the distributed network element;

sending, by the distributed network element, a UE context release message to a source centralized network element with which a connection is established in an RRC establishment phase; and

correcting, by the distributed network element, the SRB1 configuration in an RRC reconfiguration message.

6. The method according to any one of claims 1-5, wherein the method further comprises:

when receiving the RRC establishment request message from the UE, the distributed network unit searches for a centralized network unit corresponding to an operator of the PLMN selected by the UE, and if not found, rejects the RRC establishment request of the UE and does not broadcast the PLMN ID of the operator any more.

7. The method according to any one of claims 1-5, wherein the method further comprises:

starting a timer by a distributed network element when all UEs connected to a centralized network element corresponding to an operator disconnect from the distributed network element;

disconnecting, by the distributed network element, the centralized network element corresponding to the operator after the timer expires.

8. The method according to any of claims 1-5, wherein the distributed network element is a DU or IAB node of a 5G base station; the centralized network element is a CU of a 5G base station or a home IAB base station.

9. The method of any of claims 1-5, wherein the distributed network element and the centralized network element are connected by an F1 interface.

10. The method of any of claims 1-5, wherein the UE is located onboard an aircraft, the distributed network element is deployed onboard an aircraft, and the centralized network element is deployed on the ground.

11. A system for sharing a distributed network element by a plurality of operators, wherein the system comprises:

a distributed network unit, configured to broadcast PLMN ID lists of the multiple operators, determine a PLMN selected by the UE, and connect the UE to a centralized network unit corresponding to an operator of the PLMN selected by the UE, so that the UE is connected to a core network through the distributed network unit and the centralized network unit; and

a centralized network element corresponding to each of the plurality of operators.