Resource Cell Midhaul Link Reconstruction Method Based on CU-DU Separation

Abstract

This invention discloses a resource cell midhaul link reconfiguration method based on CU-DU separation, primarily addressing the difficulty of adaptive disassembly and reconfiguration of midhaul links according to service distribution and network environment conditions in existing technologies. The implementation scheme involves extending a Network Structure Orchestration (NSO) module to the existing 5G network core network side. The distributed unit collects measurement information and reports it to the centralized unit; the centralized unit makes a decision and triggers a midhaul link reconfiguration request; the NSO module and the centralized unit respond to the midhaul link reconfiguration request and release the bearer; the NSO module establishes a bit channel between the destination node's centralized unit and the distributed unit, completing the midhaul link reconfiguration. The complete resource cell midhaul link reconfiguration protocol designed in this invention overcomes the problem of adaptive reconfiguration in existing technologies, enhances network coverage, meets the QoS requirements of mobile terminals, and can be used for matching resource cell coverage structure with service distribution.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and further relates to a midhaul link reconfiguration method, which can be used to match the coverage structure of resource cells with the distribution of services. Background Technology

[0002] In recent years, with the increasing broadband access and media diversification of user services, new business scenarios such as the Internet of Things, digital twins, and ubiquitous intelligence have emerged. The three typical service categories defined by 5G—enhanced Mobile Broadband (eMBB), massive machine-type communications (mMTC) supporting massive user connections, and ultra-reliable, low-latency industrial IoT (uRLLC)—are insufficient to meet the demands of these new services. Therefore, there is a desire for 6G mobile communication networks to increase peak speeds by 50 times, throughput density by 100 times, and connection density by 100-10000 times. One of the key factors in comprehensively improving network performance is the change in network architecture. From 1G to 5G, the network architecture has transitioned from a homogeneous network composed of independently deployed traditional terrestrial macrocell base stations to a heterogeneous, dense network formed by the collaborative coverage of terrestrial macrocell base stations and terrestrial small cell base stations, and then to a three-dimensional, dense network with airborne base stations assisting terrestrial base stations in coverage. In 2009, China Mobile first proposed the concept of Centralized Cloud Radio Access Network (C-RAN), a new cellular network architecture for future mobile communication systems. For over a decade, China Mobile has continued to promote the application of this architecture in its existing networks. With the emergence of 5G and B5G concepts, the C-RAN concept is also constantly evolving. Addressing the demands of 5G such as high-frequency bands, large bandwidth, multiple antennas, massive connectivity, and low latency, C-RAN has undergone functional restructuring of centralized units (CUs) and distributed units (DUs), and introduced the next-generation fronthaul network interface (NGFI) fronthaul architecture. This continuous evolution of network architecture has improved network coverage, greatly satisfying users' needs for network coverage. However, in the existing C-RAN architecture, the separate deployment of CUs and DUs still has certain limitations. The fixed functions of network units under the C-RAN architecture mean that when radio unit AAUs (Automatic Active Units) perform cooperative transmission, the network structure cannot be flexibly adjusted according to changes in network conditions, leading to network capacity limitations. Resource cells are a wireless coverage structure proposed under the above background. This architecture innovatively couples cellular network self-organization technology with resource management technology in ultra-dense networks. Specifically, the network management module centrally orchestrates the coverage structure based on user needs, real-time network interference, and coverage monitoring information to achieve microcell base station clustering in ultra-dense networks, forming the basic spatial unit of resource cells. On this basis, the network management module performs fine-grained resource management, allocating network resources to users as needed, effectively reducing complex interference caused by network resource usage conflicts, eliminating capacity coverage holes, and improving spectrum efficiency.

[0003] China Mobile Communications Group Co., Ltd. disclosed a "C-RAN network planning method and apparatus" in its patent application CN 201711477598.3. The implementation steps are: (1) obtaining the overlap coverage of each RRU in the RRU set with other RRUs; (2) marking other RRUs with overlap coverage higher than a preset coverage threshold as adjacent RRUs; (3) selecting one RRU from the RRU set as the master RRU; (4) if the master RRU and adjacent RRUs in the RRU set, as well as any two adjacent RRUs, satisfy the preset distance threshold, they are combined into a sub-cluster; (5) removing the RRUs in the sub-cluster from the RRU set, and then selecting the next RRU from the remaining RRUs in the RRU set as the master RRU, until none of the remaining RRUs in the RRU set are adjacent to other RRUs. Although this method can achieve system-level management of resources, improve spectrum efficiency, reduce interference, and increase capacity through the 5G new wireless access network architecture C-RAN. However, this method still has two shortcomings: First, because the deployment of BBU and RRU in the C-RAN structure is fixed and the topology is fixed, it is difficult to adjust the network structure according to changes in service requirements to achieve network coverage enhancement; Second, a large number of RRUs in the C-RAN cell coverage area need to transmit uplink and downlink data or receive control information from higher layers through the mid-haul link to the BBU resource pool. The limited link resources are difficult to meet the massive information transmission, resulting in extremely high latency.

[0004] In their paper "Cell-free massive MIMO versus small cells," NGO et al. proposed a cellular-free massive MIMO coverage structure, which is an evolution of DAS and CoMP technologies. This structure consists of a massive number of access points (APs) over a large area, a central processing unit (CPU), and backhaul links. APs connect to the CPU via backhaul links. The CPU processes local channel state information collected by the APs and allocates radio resources to users based on channel conditions. Unlike cellular systems, the cellular-free massive MIMO coverage structure does not have the concept of cells. The number of users served by the system is far less than the number of antennas provided. The CPU generates flexible AP cooperative clusters based on the distribution of user traffic, equivalent to a multi-antenna transmission model, forming MISO channels to provide diversity gain for users. Compared to cellular networks, the distance from the access point to the user is significantly reduced, path loss is low, channel gain is high, and the quality of service for users can be effectively guaranteed. However, a drawback of this structure is that the massive number of APs reporting multi-dimensional network situational awareness information and channel charts to the CPU faces significant load due to limited backhaul links, resulting in a large volume of information flow.

[0005] Xi'an University of Electronic Science and Technology disclosed a "Network Coverage Enhancement Method Based on Adaptive Generation of Resource Cells" in its patent application CN 202110989309.8. The method is as follows: (1) taking traditional cells in the network as the initial state of the network; (2) generating a correlation matrix under the current network state; (3) determining whether a threshold has been reached; (4) dividing each access point into resource cells; (5) generating a network CU-DU mapping table; (6) constructing the midhaul links of each resource cell according to the CU-DU mapping table. This method solves the problem of network capacity rapidly deteriorating with the increase of user terminal density caused by low resource utilization efficiency and the problem of network resources being difficult to efficiently flow due to the static deployment of cellular cell coverage structure by dynamically merging access points to form a resource cell coverage structure and flexibly adjusting it according to changes in network conditions. However, since the adjustment of the network structure in the coverage structure of this method depends on the disassembly and connection of midhaul links between different network elements, the shape of the resource cells is difficult to adaptively reconstruct. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the existing technology by proposing a resource cell midhaul link reconfiguration method based on a CU-DU separation architecture, so as to improve the coverage of mobile communication networks, alleviate the transmission pressure of backhaul links, reduce data transmission latency, and ensure the service needs of mobile terminals.

[0007] To achieve the above objectives, the technical approach of this invention is to design a midhaul link reconfiguration protocol for resource cells based on the existing 5G centralized unit gNB-CU and distributed unit gNB-DU separation structure. This involves extending the network structure orchestration module (NSO) in the 5G core network to execute the midhaul link reconfiguration protocol. Through signaling transmission and data interaction between the distributed unit gNB-DU, the centralized unit user plane gNB-CU-UP, the centralized unit control plane gNB-CU-CP, and the network structure orchestration module (NSO), the protocol is executed to disassemble and reconnect links, thereby achieving midhaul link reconfiguration and supporting adaptive adjustment of the resource cell network structure.

[0008] Based on the above ideas, the technical solution of the present invention includes the following steps:

[0009] (1) Triggering a mid-transmission link reconfiguration request:

[0010] (1a) Expanding the network structure orchestration module NSO on the existing 5G core network side;

[0011] (1b) The distributed unit gNB-DU collects the measurement information reported by user equipment in the resource cell and forwards it to the source node centralized unit user plane gNB-CU-UP;

[0012] (1c) After receiving the measurement information, the user plane gNB-CU-UP of the source node centralized unit sends uplink radio resource control information to the control plane gNB-CU-CP of the source node centralized unit.

[0013] (1d) After receiving the uplink radio resource control information, the source node centralized unit control plane gNB-CU-CP decides whether to perform midhaul link reconstruction:

[0014] If so, a midhaul link reconfiguration request is sent to the Network Structure Orchestration Module (NSO), and step (2) is executed:

[0015] Otherwise, no request is sent, and the system waits for the next transmission of radio resource control information from the user plane gNB-CU-UP of the source node.

[0016] (2) Responding to the request for reconfiguration of the transmission link:

[0017] (2a) After receiving the mid-transmission link reconfiguration request, the Network Structure Orchestration Module (NSO) sends a bearer context establishment request to the central unit control plane (gNB-CU-CP) of the destination node.

[0018] (2b) After receiving the bearer context establishment request, the destination node centralized unit control plane gNB-CU-CP first sends a response frame to the network structure orchestration module NSO, and then sends a bearer context establishment message to its user plane gNB-CU-UP.

[0019] (2c) The user plane gNB-CU-UP of the destination node centralized unit receives the bearer context establishment request and sends a response frame to the control plane gNB-CU-CP of the destination node centralized unit;

[0020] (2d) The Network Structure Orchestration Module (NSO) sends a bearer context modification request to the source node centralized unit control plane (gNB-CU-CP);

[0021] (2e) After receiving the bearer context modification request, the source node centralized unit control plane gNB-CU-CP sends a response frame to the network structure orchestration module NSO and sends the bearer context modification request to the source node centralized unit user plane gNB-CU-UP.

[0022] (2f) The source node centralized unit user plane gNB-CU-UP receives the bearer context modification request and sends a response frame to the source node centralized unit control plane gNB-CU-CP;

[0023] (3) Establish a mid-haul link:

[0024] (3a) The Network Structure Orchestration Module (NSO) sends a data forwarding command to the user plane gNB-CU-UP of the source node centralized unit.

[0025] (3b) The source node centralized unit user plane gNB-CU-UP receives the data forwarding instruction and forwards the data unit to the destination node centralized unit user plane gNB-CU-UP.

[0026] (3c) The Network Structure Orchestration Module (NSO) sends an end marker packet to the user plane gNB-CU-UP of the source node centralized unit;

[0027] (3d) After receiving the end marker packet, the source node centralized unit user plane gNB-CU-UP stops forwarding data units to the destination node centralized unit user plane gNB-CU-UP, and at the same time forwards the end marker packet to the destination node centralized unit user plane gNB-CU-UP.

[0028] (3e) The source node centralized unit control plane gNB-CU-CP sends a bearer release request to the source node centralized unit user plane gNB-CU-UP;

[0029] (3f) The user plane gNB-CU-UP of the source node centralized unit releases the bearer and sends a bearer release completion message to the control plane gNB-CU-CP of the source node centralized unit. At the same time, the bearer release completion message is forwarded to the network structure orchestration module NSO.

[0030] (3g) After receiving the bearer release completion message, the Network Structure Orchestration Module (NSO) establishes a data path from the destination node centralized unit gNB-CU to the distributed unit gNB-DU, thus completing the reconstruction of the mid-transmission link.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] First, this invention extends the existing 5G core network functions by adding a Network Structure Orchestration (NSO) module. This module can receive midhaul link reconfiguration requests reported by the centralized unit control plane (gNB-CU-CP), execute midhaul link reconfiguration procedures, and realize the reconfiguration and adjustment of midhaul links in resource cells through data interaction and signaling transmission with the centralized unit (gNB-CU) and distributed unit (gNB-DU) on the access network side. Compared with existing resource cell adaptive methods, this invention virtualizes, modularizes, and centralizes some functions of the Network Resource Orchestrator (OMC) to the core network, which facilitates the establishment, modification, and maintenance of midhaul links.

[0033] Secondly, this invention employs a complete midhaul link reconfiguration protocol for resource cells. This protocol can be triggered either by the distributed unit (gNB-DU) on the access network side based on local network state information, or by the network structure orchestration module (NSO) on the core network side based on global network state information. Furthermore, since the complexity of executing this protocol does not increase superlinearly with network expansion and complexity, it effectively alleviates the transmission pressure on backhaul links and reduces data transmission latency. Therefore, it solves the problem of existing resource cell adaptive methods lacking a midhaul link reconfiguration protocol and meets the needs of flexible network structure changes.

[0034] Third, based on the 5G network architecture, this invention designs the interaction signaling and interaction process of the destination node centralized unit, the source node centralized unit, the network structure orchestration module, and the distribution unit. This solves the problem that resource cells are difficult to adaptively disassemble and reconstruct the midhaul link according to the distribution of services in the network and the network environment status. It supports the elastic matching of resource cell coverage structure and service distribution, realizes enhanced network coverage capability, and meets the QoS requirements of mobile terminals. Attached Figure Description

[0035] Figure 1 This is the overall flowchart of the implementation of this invention;

[0036] Figure 2 This is a sub-flowchart of the response to the transmission link reconfiguration request in this invention;

[0037] Figure 3 This is a sub-flowchart for establishing a transmission link in this invention;

[0038] Figure 4 This is a schematic diagram of the AAU-CU-DU three-level separation architecture used in the micro base station in this embodiment of the invention;

[0039] Figure 5 This is a schematic diagram of the extended 5G network structure in an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the network structure used in the embodiments of the present invention. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0042] In the initial state, the present invention assumes that there is a mid-haul link between the distributed unit gNB-DU and the source node centralized unit user plane gNB-CU-UP, and uplink and downlink information are transmitted through this mid-haul link. The source node centralized unit user plane gNB-CU-UP and the source node centralized unit control plane gNB-CU-CP interact with each other through the E1 interface. gNB-CU-CP interacts with the network structure orchestration module NSO through the interface of the control plane.

[0043] Reference Figure 1 The implementation steps for mid-haul link reconfiguration in the above-mentioned scenario are as follows:

[0044] Step 1: Trigger mid-transmission link reconfiguration.

[0045] 1.1) Expand the network structure orchestration module (NSO) on the existing 5G core network side;

[0046] 1.2) The distribution unit gNB-DU collects the measurement information reported by user equipment in the resource cell and forwards it to the source node centralized unit user plane gNB-CU-UP. The measurement information includes the channel gain between the user and the base station, the user's service requirements and the user's IP.

[0047] 1.3) After receiving the measurement information, the user plane gNB-CU-UP of the source node centralized unit sends uplink radio resource control information to the control plane gNB-CU-CP of the source node centralized unit. The uplink radio resource control information mainly includes connection establishment and release information, system information broadcast information, radio bearer establishment information, reconfiguration and release information, connection mobility process information, paging notification and release information, and power control information.

[0048] 1.4) After receiving uplink radio resource control information, the source node centralized unit control plane gNB-CU-CP decides whether to perform midhaul link reconstruction:

[0049] If a retransmission is decided, a midhaul link reconfiguration request is sent to the Network Structure Orchestration Module (NSO), and step 2 is executed:

[0050] Otherwise, no request is sent, and the system waits for the next transmission of radio resource control information from the user plane gNB-CU-UP of the source node.

[0051] Step 2: The network structure orchestration module and the centralized unit respond to the transmission link reconfiguration request.

[0052] Reference Figure 2 The specific implementation of this step is as follows:

[0053] 2.1) After receiving the mid-transmission link reconfiguration request, the Network Structure Orchestration Module (NSO) sends a bearer context establishment request to the central unit control plane (gNB-CU-CP) of the destination node. The bearer context establishment request is a request to establish an information transmission channel between the central unit (gNB-CU) and the distributed unit (gNB-DU). Its context content includes signaling information and service data between the central unit (gNB-CU) and the distributed unit (gNB-DU).

[0054] 2.2) After receiving the bearer context establishment request, the destination node centralized unit control plane gNB-CU-CP first sends a response frame to the network structure orchestration module NSO, and then sends a bearer context establishment message to its user plane gNB-CU-UP.

[0055] 2.3) The user plane gNB-CU-UP of the destination node centralized unit receives the bearer context establishment request and sends a response frame to the control plane gNB-CU-CP of the destination node centralized unit;

[0056] 2.4) The Network Structure Orchestration Module (NSO) sends a bearer context modification request to the source node centralized unit control plane gNB-CU-CP, which is a request to modify the information transmission channel between the centralized unit gNB-CU and the distributed unit gNB-DU.

[0057] 2.5) After receiving the bearer context modification request, the source node centralized unit control plane gNB-CU-CP sends a response frame to the network structure orchestration module NSO and sends the bearer context modification request to the source node centralized unit user plane gNB-CU-UP.

[0058] 2.6) The source node centralized unit user plane gNB-CU-UP receives the bearer context modification request and sends a response frame to the source node centralized unit control plane gNB-CU-CP.

[0059] Step 3: Establish the mid-transmission link.

[0060] Reference Figure 3 The specific implementation of this step is as follows:

[0061] 3.1) The Network Structure Orchestration Module (NSO) sends a data forwarding instruction to the source node centralized unit user plane gNB-CU-UP, that is, instructs the source node centralized unit user plane gNB-CU-UP to forward the data unit to the destination node centralized unit user plane gNB-CU-UP.

[0062] 3.2) After receiving the data forwarding instruction, the source node centralized unit user plane gNB-CU-UP forwards the data unit to the destination node centralized unit user plane gNB-CU-UP, that is, the user information and distribution unit gNB-DU information cached by the centralized unit user plane gNB-CU-UP.

[0063] 3.3) The Network Structure Orchestration Module (NSO) sends an end marker packet to the user plane gNB-CU-UP of the source node's centralized unit;

[0064] 3.4) After receiving the end marker packet, the source node centralized unit user plane gNB-CU-UP stops forwarding data units to the destination node centralized unit user plane gNB-CU-UP, and at the same time forwards the end marker packet to the destination node centralized unit user plane gNB-CU-UP.

[0065] 3.5) The source node centralized unit control plane gNB-CU-CP sends a bearer release request to the source node centralized unit user plane gNB-CU-UP. This bearer release request refers to the request to disconnect the data path between the source node centralized unit control plane gNB-CU-UP and the destination node centralized unit user plane gNB-CU-UP.

[0066] 3.6) The source node centralized unit user plane gNB-CU-UP releases the bearer and sends a bearer release completion message to the source node centralized unit control plane gNB-CU-CP, and forwards the bearer release completion message to the network structure orchestration module NSO.

[0067] 3.7) After receiving the bearer release completion message, the Network Structure Orchestration Module (NSO) establishes a bit channel between the destination node centralized unit gNB-CU and the distributed unit gNB-DU to carry uplink and downlink service information and control information, thus completing the reconstruction of the mid-transmission link.

[0068] Example:

[0069] To facilitate understanding of this invention, the following embodiment will be described using two resource cells and a network structure orchestration module (NSO) deployed in a network as an example.

[0070] The base station in the network adopts a 5G RAN AAU-DU-CU separated physical and logical structure, in which:

[0071] Physical structure such as Figure 4 As shown in (a), it includes a centralized unit gNB-CU, a distributed unit gNB-DU, and three active antenna units AAU. The centralized unit gNB-CU handles non-real-time services and is deployed in a centralized and virtualized manner. The distributed unit gNB-DU handles real-time services. The active antenna units AAU are deployed at remote locations to provide signal coverage. The centralized unit gNB-CU and the distributed unit gNB-DU are connected via a midhaul link, and the distributed unit gNB-DU and the active antenna units AAU are connected via a fronthaul link.

[0072] Logical structure such as Figure 4As shown in (b), it includes a centralized unit control plane gNB-CU-CP and several centralized unit user planes gNB-CU-UP. The control plane gNB-CU-CP is mainly responsible for signaling interaction, while the user plane gNB-CU-UP is mainly responsible for processing uplink and downlink service data. The F1-C interface establishes the connection between the control panel gNB-CU-CP and the distributed unit gNB-DU. The E1 interface is responsible for the interaction between the control panel gNB-CU-CP and the user panel gNB-CU-UP. The user panel gNB-CU-UP then handles the uplink and downlink service data processing of one or more distributed units gNB-DU through the F1-U interface.

[0073] This example extends the Network Structure Orchestration Module (NSO) into an existing 5G network architecture to execute midhaul link reconfiguration procedures. The extended 5G network architecture is as follows: Figure 5 As shown, Figure 5 The area inside the dashed box is the core network, and the area outside the dashed box is the access network. The core network contains NEF, NRF, PCF, UDM, AF, AUSF, AMF, SMF, UPF, and NSO modules. The access network contains UE network elements, RAN network elements, and DN network elements. The network structure orchestration module NSO can communicate with the central unit via the backhaul link for uplink and downlink signaling and data exchange. For example, it can receive midhaul link reconfiguration requests reported by the central unit and send context bearer establishment requests, context bearer modification requests, data forwarding instructions, and other control information.

[0074] The extended 5G network is used to perform signaling interaction and data transmission with centralized and distributed units within the resource cell, thereby achieving midhaul link reconfiguration. The specific process is as follows:

[0075] The initial state of the network is as follows: Figure 6 As shown in (a), there is a mid-haul link between the distributed unit gNB-DU-0 and the source node centralized unit SourcegNB-CU, and uplink and downlink information are transmitted through this mid-haul link. This mid-haul link is as follows: Figure 6 As shown by the solid double-headed arrow in (a), the source node user plane Source gNB-CU-UP and the source node centralized unit control plane Source gNB-CU-CP exchange information through the E1 interface. The source node centralized unit control plane Source gNB-CU-CP exchanges information with the network structure orchestration module NSO through the control plane interface. The distribution unit gNB-DU-0 collects the measurement information reported by user equipment UE1, UE2 and UE3 and forwards it to the source node centralized unit user plane Source gNB-CU-UP. The measurement information is the collected network multidimensional perception information, such as the channel gain between the user and the antenna, the user's service requirements and the distribution of the user.

[0076] When the network environment changes, the distributed unit gNB-DU-0 cannot guarantee the service requirements of mobile terminals UE1, UE2, and UE3. At this time, the source node central unit gNB-CU reports a midhaul link reconfiguration request to the network structure orchestration module NSO. Upon receiving the request, the network structure orchestration module immediately responds, releasing the midhaul link between the source node central unit gNB-CU and the distributed unit gNB-DU-0, and reserving a bit channel between the destination node central unit gNB-CU and the distributed unit gNB-DU-0. The network status at this time is as follows: Figure 6 As shown in (b) in the figure, the cross indicates that the link is broken, and the dashed line indicates that the target node centralized unit gNB-CU is a transmission channel reserved for gNB-DU-0.

[0077] After the transmission channel is reserved, the source node centralized unit user plane (Source gNB-CU-UP) forwards the user information and RRC radio resource control information cached by the distribution unit (gNB-DU-0) to the destination node centralized unit user plane (Target gNB-CU-UP). After all the above information has been forwarded, the network structure orchestration module (NSO) establishes a data path from the destination node centralized unit (Target gNB-CU) to the distribution unit (gNB-DU-0), completing the reconfiguration of the midhaul link. The reconfigured network state is as follows: Figure 6 As shown in (c), the double-headed solid line represents the established mid-haul link between gNB-DU and the target node centralized unit gNB-CU.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reconfiguring midhaul links in resource cells based on CU-DU separation, characterized in that, Includes the following steps: (1) Trigger the mid-transmission link reconfiguration procedure: (1a) The distribution unit gNB-DU collects the measurement information reported by user equipment in the resource cell and forwards it to the source node centralized unit user plane gNB-CU-UP; (1b) After receiving the measurement information, the user plane gNB-CU-UP of the source node centralized unit sends uplink radio resource control information to the control plane gNB-CU-CP of the source node centralized unit; (1c) After receiving the uplink radio resource control information, the source node centralized unit control plane gNB-CU-CP decides whether to perform midhaul link reconstruction: If so, a midhaul link reconfiguration request is sent to the Network Structure Orchestration Module (NSO), and step (2) is executed: Otherwise, no request is sent, and the system waits for the next transmission of radio resource control information from the user plane gNB-CU-UP of the source node. (2) Responding to the request for reconfiguration of the transmission link: (2a) After receiving the mid-transmission link reconfiguration request, the Network Structure Orchestration Module (NSO) sends a bearer context establishment request to the central unit control plane (gNB-CU-CP) of the destination node. (2b) After receiving the bearer context establishment request, the destination node centralized unit control plane gNB-CU-CP first sends a response frame to the network structure orchestration module NSO, and then sends a bearer context establishment message to its user plane gNB-CU-UP. (2c) The user plane gNB-CU-UP of the destination node centralized unit receives the bearer context establishment request and sends a response frame to the control plane gNB-CU-CP of the destination node centralized unit; (2d) The Network Structure Orchestration Module (NSO) sends a bearer context modification request to the source node centralized unit control plane (gNB-CU-CP); (2e) After receiving the bearer context modification request, the source node centralized unit control plane gNB-CU-CP sends a response frame to the network structure orchestration module NSO and sends the bearer context modification request to the source node centralized unit user plane gNB-CU-UP. (2f) The source node centralized unit user plane gNB-CU-UP receives the bearer context modification request and sends a response frame to the source node centralized unit control plane gNB-CU-CP; (3) Establish a mid-haul link: (3a) The network structure orchestration module NSO sends a data forwarding command to the source node centralized unit user plane gNB-CU-UP; (3b) The source node centralized unit user plane gNB-CU-UP receives the data forwarding instruction and forwards the data unit to the destination node centralized unit user plane gNB-CU-UP; (3c) The Network Structure Orchestration Module (NSO) sends an end marker packet to the user plane gNB-CU-UP of the source node centralized unit; (3d) After receiving the end marker packet, the source node centralized unit user plane gNB-CU-UP stops forwarding data units to the destination node centralized unit user plane gNB-CU-UP, and at the same time forwards the end marker packet to the destination node centralized unit user plane gNB-CU-UP. (3e) The source node centralized unit control plane gNB-CU-CP sends a bearer release request to the source node centralized unit user plane gNB-CU-UP; (3f) The user plane gNB-CU-UP of the source node centralized unit releases the bearer and sends a bearer release completion message to the control plane gNB-CU-CP of the source node centralized unit. At the same time, the bearer release completion message is forwarded to the network structure orchestration module NSO. (3g) After receiving the bearer release completion message, the Network Structure Orchestration Module (NSO) establishes a data path from the destination node centralized unit gNB-CU to the distributed unit gNB-DU, thus completing the reconstruction of the mid-transmission link.

2. The method according to claim 1, characterized in that, The measurement information in step (1a) includes: channel gain between the user and the base station, the user's service requirements, and the user's IP address.

3. The method according to claim 1, characterized in that, The uplink radio resource control information in step (1b) includes: connection establishment and release information, system information broadcast information, radio bearer establishment information, reconfiguration and release information, connection mobility process information, paging notification and release information, and power control information.

4. The method according to claim 1, characterized in that, The bearer context establishment request in step (2a) refers to the request to establish an information transmission channel between the centralized unit gNB-CU and the distributed unit gNB-DU. Its context content includes signaling information and service data between the centralized unit gNB-CU and the distributed unit gNB-DU.

5. The method according to claim 1, characterized in that, The bearer context modification request in step (2d) refers to modifying the information transmission channel established between the centralized unit gNB-CU and the distributed unit gNB-DU.

6. The method according to claim 1, characterized in that: The data unit in step (3b) refers to the user information cached in the centralized unit user plane gNB-CU-UP and the distributed unit gNB-DU information corresponding to the centralized unit user plane gNB-CU-UP of the source node.

7. The method according to claim 1, characterized in that, The bearer release request in step (3e) refers to disconnecting the data path between the source node centralized unit control plane gNB-CU-UP and the destination node centralized unit user plane gNB-CU-UP.

8. The method according to claim 1, characterized in that, The data path established in step (3g) refers to the bit channel between the centralized unit gNB-CU and the distributed unit gNB-DU that carries uplink and downlink service information and control information.

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