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After accessing the 5GC via non3GPP WALN, the terminal (UE) starts PDU session establishment after completing registration, authentication and authorization, during which user data, uplink and downlink traffic and QoS are defined as follows;   I. User plane After completing the PDU session establishment and establishing the user plane IPsec sub-SA between the UE and the N3IWF, the UE can use the established IPsec sub-SA and the associated GTPU tunnels between the N3IWF and the UPF to send upstream and downstream traffic with various QoS flows for the session over the untrusted WLAN network.   II.When the UE has to transmit a UL PDU, it shall determine the QFI associated with the PDU using the QoS rules of the corresponding PDU session and encapsulate the PDU in a GRE packet, with the QFI value located in the header of the GRE packet.The UE shall forward the GRE packet to the N3IWF via the IPsec sub-SA associated with the QFI by encapsulated into an IPsec packet in tunnel mode, with the source address being the UE IP address and the destination address being the UP IP address associated with the sub-SA.   When the N3IWF receives a UL PDU, it shall decapsulate the IPsec header and the GRE header and determine the GTPU tunnel ID corresponding to the PDU session.The N3IWF shall encapsulate the UL PDU in a GTPU packet and place the QFI value in the header of the GTPY packet and forward the GTPU packet to the UPF via the N3. III.Downstream Traffic When the N3IWF receives a DL PDU from the UPF via the N3, the N3IWF shall decapsulate the GTPU header and use the QFI and the PDU session identifier in the GTPU header to determine the IPsec Child SA to be used to send the DL PDU to the UE via the NWu.   The N3IWF shall encapsulate the DL PDU within a GRE packet and place the QFI value in the header of the GRE packet.The N3IWF may also include a Reflected QoS Indicator (RQI) in the GRE header, which shall be used by the UE to enable Reflected QoS.The N3IWF shall forward the GRE packet, along with the DL PDU, through the IPsec Child SA associated with the QFI to the UE by encapsulating the GRE packet into an IP packet in tunnel mode, where the source address is the UP IP address associated with the sub-SA and the destination address is the address of the UE.   IV.QoS For UEs accessing the 5GCN over untrusted WLANs, the N3IWF supports QoS differentiation and mapping of QoS flows to non 3GPP access resources.The QoS flows are controlled by the SMF and can be pre-configured or established through the PDU session establishment or modification process requested by the UE.The N3IWF shall determine the user plane to be established based on the local policy, configuration, and QoS profile received from the network. profile to determine the number of user plane IPsec sub-SAs to be established and the QoS profile associated with each sub-SA. The N3IWF shall then initiate an IPsec SA creation process to the UE to establish the sub-SAs associated with the QoS flows of the PDU session.The QoS functions of the UE, the N3IWF, and the UPF are specified in figure (1) below.   Figure 1.QoS for ungranted WLAN access to 5GCNs   Non-granted non 3GPP access essentially corresponds to a WLAN interworking with 5GCN, which is served over N3IWF. However, unlike earlier architectures in which the WLAN pass-through network elements (PDG/ePDG) were part of the 3GPP core network, the N3IWF acts as an access network similar to the 3GPP access. This allows common procedures for registration, authentication and session handling in both 3GPP Access and non 3GPP Access. Paging, mobile registration, and periodic registration are not supported in non-granted WLANs. Multiple PDU sessions can be established on both 3GPP access and non-granted WLANs, and PDU sessions can be switched between them. It is also possible to establish multiple access PDU sessions on 3GPP Access and Ungranted WLANs that support ATSSS.  

After accessing 5GC via non 3GPP, the terminal (UE) will start PDU session establishment after completing registration, authentication and authorization, and the specific processes are as follows; I. PDU Session Establishment After the terminal (UE) accesses the 5GC via WLAN, the PDU session establishment involves N31WF, AMF, SMF, and UPFF, etc., and the flow is shown in Figure (1) below;   Fig. 1.PDU session establishment of 5GCN terminal (UE) accessed via WLAN   II. PDU session establishment steps The UE sends a PDU session establishment request using NAS signaling IPsec SA to the N3IWF, which transparently forwards it to the AMF in a NAS UL message. A process similar to the PDU session establishment in 3GPP access is performed in the 5GCN (shown in Figure 1 above). The AMF sends an N2 PDU Session Resource Setup Request message to the N3IWF to establish the WLAN resources for this PDU session. This message includes the QoS profile and associated QFI, PDU session ID, UL GTPU tunnel information, and NAS PDU session establishment acceptance. The N3IWF determines the number of IPsec sub-SAs to be established and the QoS profile associated with each IPsec sub-SA based on its own policy, configuration, and QoS profile received. The N3IWF sends an IKE Create Sub-SA request to establish the first IPsec sub-SA of the PDU session. which includes the QFI, PDU session ID, and UP IP address associated with the sub-SA, as well as an optional DSCP value and default sub-SA indication. The UE sends an IKE Create Sub-SA response when it accepts an IKE Create Sub-SA request. The N3IWF establishes determines other IPsec sub-SAs, each associated with one or more QFIs and a UP IP address. After all IP sub-SAs are established, the N3IWF forwards a PDU Session Establishment Acceptance message to the UE via the signaling IPsec SA to initiate UL data. The N3IWF also sends an N2 PDU Session Resource Setup Response to the AMF that includes the DL GTPU Tunnel information, which further performs a process similar to the PDU Session Establishment process in 3GPP Access (as shown in Figure 1) and enables the initiation of D Data.   The PDU session for 3GPP access may be serviced by a different SMF than the one that serves the PDU session for non3GPP access.   III. PDU session deactivation The deactivation of an existing PDU session UP connection results in the deactivation of the corresponding NWu connection (i.e., IPsec sub-SA and N3 tunnel). When the UE is in the CM-CONNECTED state, it can independently deactivate the UP connections of different PDU sessions. If the PDU session is an always-on PDU session, the SMF shall not deactivate the UP connection for this PDU session due to inactivity. Release of a PDU session via non3GPP access does not imply release of the N2 connection.   IV. Paging Issues The non-granting WLAN does not support paging; therefore, when the AMF receives a message corresponding to the PDU session of the UE in CM-IDLE state in non3GPP access, it may perform the network-triggered service request procedure over 3GPP access regardless of the 3GPP access UE state. The network-triggered service request procedure for non3GPP access can also be executed in the AMF for the UE in CM-IDLE state in 3GPP access and for the UE in CM-CONNECTED state in non 3GPP access when 3GPP access paging is not performed.   V. 3GPP and non 3GPP Access Multiple PDU Sessions A UE registered over both 3GPP access and non-granted WLAN may have multiple PDU sessions on both accesses, with each PDU session being active in only one of the accesses. When the UE switches to CM-IDLE in either access, the UE may move the PDU session in the corresponding access to the target access according to the UE policy.The UE may need to initiate the registration procedure for the switchover in the target access, and then initiate the PDU session to establish and move the PDU session ID of the session; the core network maintains the PDU session but deactivates the N3 user-plane connection for such PDU session; Depending on the implementation the UE may initiate the logout procedure in the absence of PDU session access.   VI. Multiple Access PDU Sessions 3GPP Release16 supports Access Traffic Control, Switching and Splitting (ATSSS), which allows PDU sessions with multiple packet flows in a multiple access PDU session to be able to select either a 3GPP access or an untrusted WLAN for each of the packet flows or the packet flows to be able to switch between a 3GPP access and an ungranted WLAN or the packet flows to be able to split between 3GPP access and untrusted WLAN; the PDU session establishment process contains additional information and user plane establishment for the same purpose.

1、Self-healing is the ability of a wireless network in a SON to automatically detect and localize most faults and apply self-healing mechanisms to resolve many types of faults; for example, reducing output power or automatically reverting to a previous software version in the event of a temperature fault.   2、All areas of the existing network may fail from time to time, and many of these failures can be overcome by self-healing without major problems and in many cases spare hardware can be used. Self-healing of wireless networks mainly involves the following areas:   software self-recovery - the ability to revert to a previous version of software when a problem occurs. circuit failure self-healing - usually involves redundant circuits that can be switched over to spare circuits. unit interrupt detection-identifying problems by remotely inspecting a specific unit. unit outage recovery - routines to assist in unit recovery, which may include detection and diagnosis as well as automated recovery solutions and reporting of operational results. cell outage compensation - A method of providing optimal service to users during maintenance.   3、Fault Management and Self-Repair Wireless cells shall be able to easily return to a pre-failure state through self-repair, thus eliminating any compensation operations that may have been initiated; network fault management and correction requires significant human intervention, automated wherever possible; therefore, fault identification and self-repair is an important solution, and the following points are important components of the solution: Automatic Fault Recognition Equipment faults are usually detected automatically by the equipment itself. However, fault detection messages are not always generated or transmitted when the detection system itself is damaged. eNodeB Such unrecognized faults are often referred to as dormant cells, and they are detected through performance statistics. Cell Outage Compensation When a device failure is detected, the SON analyzes the device's internal logs to identify the root cause and takes some recovery actions, such as reverting to a previous software version or switching to a standby cell. When an equipment failure cannot be resolved by these measures, the affected and neighboring cells will take collaborative measures to minimize the quality degradation perceived by users. For example, in urban areas covered by multiple microcells, it is effective to relocate users from a faulty cell to a normal cell by collaboratively adjusting coverage and switching related parameters in nearby cells. This can shorten the fault recovery time and assign maintenance staff more efficiently.

In the 5G(NR) system, two types of data units, PDU and SDU, are passed between the terminal and the network respectively, and usually the terminal (UE) provides end-to-end user-plane connectivity between the UPF (User-Place Function) and the DN (Specific Data Network) through the PDUSession; this is because the SDU is passed from the OSI layer or sublayer to the lower layer in the OSI-based (Open System Interconnection) system, and the SDU has not been encapsulated into the PDU (Protocol Data Unit) by the lower layer. OSI (Open System Interconnection) based systems SDUs are data units passed from the OSI layer or sub-layer to the lower layers, which have not yet been encapsulated into PDUs (Protocol Data Units) by the lower layers, whereas the SDUs are encapsulated into the lower layer's PDUs and the process continues until the PHY (Physical Layer) of the OSI stack. Regarding SDU and PDU in 5G(NR), 3GPP defines them as follows;     1、 SDU(Service Data Unit) Definition:A Service Data Unit (SDU) is a unit of data that is passed from the upper layer to the lower layer in the network protocol stack; the SDU contains the payload or the data that needs to be transmitted, and the upper layer expects the lower layer to be able to transmit this data. Role:SDUs are essentially data that a service (application or process) wishes to transmit using the underlying network. When the SDU is passed to the lower protocol layer for transmission, it may be combined with other information (e.g., header or tail) to convert it into a Protocol Data Unit (PDU) appropriate for that layer. 2、The PDU (protocol data unit) Definition:A PDU (Protocol Data Unit) is a combination of SDUs and protocol-specific control information (e.g., header and tail). Each layer in the network can add or remove its own PDU header or tail, thus encapsulating or decapsulating the SDU as it passes through the layers. Role:A PDU represents a packet with SDUs (raw service data) and control information required for the network to process the data correctly. This control information can include error checking, segmentation, identification, and other control mechanisms to ensure that the data can be properly routed and transmitted. 3、SDUs and PDUs The use of SDUs and PDUs in 5G(NR) networks is critical to ensure that data is properly formatted and processed at different layers, where Layer2 in 5G(NR) handles PDUs and SDUs as follows: PDCP Layer:Handles PDCP PDUs, which encapsulate upper layer SDUs (from RRC or user data) with control information (e.g., sequence numbers and header compression) for efficient transmission. RLC Layer:Manages RLC PDUs, segments and reorganizes RLC SDUs to ensure reliable transmission of data over the network. MAC Layer:Utilizes the MAC PDU aspect of formatted data units containing primarily MAC headers and payloads to ensure that data is efficiently scheduled and transmitted by the physical layer. 4、The data processing process 5G (NR) system data processing specific process is shown in the following figure:

One of the new protocols introduced in the 5G(NR) stack is the CUPS (Control and User Plane Separation) architecture; a form of architecture that allows for the separation of control-plane functionality from user-plane functionality, thus providing greater flexibility and efficiency in managing network traffic and resources.CUPS, an important feature in 5G, enables more dynamic and efficient network operations.   Ⅰ、Definition of CUPS This is an architectural concept introduced in 5G(NR), which divides the network functions into two different planes: the control plane and the user plane, and each of these planes has a specific purpose in the network, where.   1.1 The Control Plane is responsible for managing the signaling and control functions of the network; it handles tasks such as network setup, resource allocation, mobility management, and session establishment. Functions in the Control Plane are typically more sensitive to latency and require real-time processing.   1.2 The User Plane handles the actual user data traffic, which carries user-generated content such as web pages, videos, and other application data. Functions in the User Plane focus on providing high throughput and low latency for data transfer.   Ⅱ、The CUPS architecture benefits mainly in; Flexibility:CUPS provides network operators with the flexibility to independently extend and manage control and user plane functions. This means they can allocate resources more efficiently based on traffic demand. Network Optimization: With separate control and user planes, operators can allocate workloads as needed to optimize network performance. Resource Efficiency:CUPS allows dynamic resource allocation, ensuring that control plane tasks do not impact user plane performance and vice versa. Service Innovation: It supports the creation of innovative services and applications that require low latency, high bandwidth and efficient resource management.   Ⅲ、Implementing Use Cases CUPS is particularly beneficial for applications such as IoT (Internet of Things) that require efficient management of many devices. It is also critical for low-latency services such as AR (Augmented Reality), VR (Virtual Reality), and V2X (Self-Driving Cars), where minimal latency in data processing is critical.   Ⅳ、CUPS Implementation The network infrastructure needs to be upgraded to support the separation of these planes. This typically involves the use of SDN (Software Defined Networking) and NFV (Network Functions Virtualization) technologies.CUPS (Control and User Plane Separation) is a fundamental architectural feature introduced in the 5G (NR) stack that enhances network agility, efficiency, and performance by separating control and user-plane functions to enable dynamic resource allocation and enable innovative services with low latency requirements.  

In addition to the 2G~5G mobile communication technologies defined by 3GPP, there are also wireless communication supported by non 3GPP such as Wi-Fi, Bluetooth and NTN (satellite communication) in the wireless communication system; 3GPP has introduced the support for non 3GPP in the 5G core network since Release17, which means that NTN and others can also access 5GC defined by 3GPP, and terminals can realize the mobility between 3GPP and non 3GPP; i. Interworking with non 3GPP This is to realize the interaction between the non-granted non 3GPP network and the 5G core network (5GC). The terminal can realize the movement between 3GPP and non 3GPP;   1、Interworking with non3GPP This is to realize the interworking between the non-granted non 3GPP network and the 5G core network (5GCN); during this period, the N3IWF will act as a gateway to the 5GCN and support the N2 and N3 interfaces to the 5GCN; the N3IWF will also provide a secure connection for the terminals (UEs) that are accessing the 5GCN through the non 3GPP network, and support IPsec between the UEs and the N3IWF. ii. IPsec between UE and N3IWF.   2、The interfaces, agreements and procedures, and QoS in the architecture for non-credit non 3GPP network interworking with the 5G core support control plane (CP) functionality, including registration and PDU session establishment, as well as user plane (UP) functionality, including non-credit non 3GPP access and QoS in N3IWF. Currently, the 3GPP specification only supports WLAN (Wireless Local Area Network (Wi-Fi) Access Network) as a non 3GPP access network;   3、Why do we need non 3GPP? Non-credit WLANs include public hotspots, home Wi-Fi, enterprise Wi-Fi, etc. that are not traditionally under the control of the mobile network operator By enabling convergence with individual 5GCNs that provide a variety of IP-based services, these non-credit non3GPP/WLANs can complement 3GPP radio access network coverage and address the following issues: Increased capacity and intelligent traffic offloading to avoid data congestion and reduce backhaul costs; Providing better coverage and connectivity in high-density traffic environments and indoor environments; Value-added services, innovative mobile solutions and mobile engagement creating new business opportunities; Increased capacity and unified management reducing capital and operating costs for operators; Providing enhanced services to customers in a cost-effective manner. 4、WLAN and 3GPP As shown in Figure (1) below untrusted WLAN and 3GPP mobile network can access 3GPP network before 4G/5G from untrusted WLAN through WAG (Wireless Access Gateway) and PDG (Packet Data Gateway). Wherein:The PDG comprises a subset of TTG (Tunnel Terminal Gateway) and GGSN functionality that works in concert with the TTG.The AAA server is used to authenticate the UE through the WAG using EAP-AKA/EAP-SIM authentication over the untrusted WLAN. CP (control) signaling between the TTG and the GGSN uses the GTPC agreement and establishes a PDP context for the user session. For each established UE session the IPsec tunnel terminates at the TTG and establishes the corresponding GTPU tunnel to the GGSN.   5、The 4G network can be accessed from untrusted WLANs through the ePDG (Evolved Packet Data Gateway) using EAP-AKA/EAP-AKA authentication and AAA server. the CP signaling between the ePDG and the PGW uses the GTPC/PMIP agreement and establishes the bearer for the user session. For each UE session established over the untrusted WLAN. the IPsec tunnel terminates at the ePDG and establishes the corresponding GTPU/GRE tunnel to the PGW. The dual-stack MIPv6 agreement can also be used to establish IPsec between the UE and the ePDG for CP signaling, and to establish a tunnel between the UE and the PGW for user-plane (UP) messaging.

Into the 5G era often heard about non 3GPP access to 5G (NR) system discussion; then 3GPP and non 3GPP what is the difference?   1、3GPP and non 3GPP 3GPP (Third Generation Partnership Project) is a cooperation between various telecommunication standard organizations, which defines the cellular network technology standards include: 2G (GSM), 3G (UMTS), 4G (LTE) and 5G (NR). non 3GPP refers to other network technologies and standards outside the scope of 3GPP, such as Wi-Fi, Bluetooth and satellite networks. These non 3GPP technologies are typically used to complement 3GPP-defined cellular network communications. 2、3GPP and non 3GPP differ in that they manage different standards and specifications for communications networks, among others: 3GPP (Third Generation Partnership Project) is an organization that develops and maintains global standards for mobile telecommunications, including 2G, 3G, 4G and 5G technologies. non 3GPP, on the other hand, refers to other communication technologies or standards not defined by 3GPP, such as Wi-Fi, Bluetooth or NTN (satellite communications), which may use different agreements and standards. 3、3GPP stands for the Third Generation Partnership Project, an international body responsible for developing and maintaining technical standards for mobile telecommunications, which defines technical standards, including 2G, 3G, 4G and 5G, to ensure mobile network and device interoperability and global compatibility.   4、3GPP and non 3GPP interoperability 3GPP and non 3GPP through the GID (Global Identifier) to identify each other access to the mobile communications network, in the common identifier GID includes: IMSI (International Mobile Subscriber Identity) and IMEI (International Mobile Equipment Identity) and other identifiers. These identifiers are used to manage and verify different types of network access users and devices.   5、LTE and 3GPP LTE (Long-Term Evolution) is a specific technology developed and standardized by 3GPP as part of its 4G network specification; and the range of standards and technologies covered by 3GPP is not limited to LTE, but also includes earlier technologies such as 2G, 3G, and future technologies such as 5G. Thus, while LTE is a product of 3GPP's work, 3GPP itself represents a broader range of mobile network standards and specifications.

3GPP (Third Generation Partnership Project) is an international collaboration among seven telecommunication standards development organizations (ARIB, ATIS, CCSA, ETSI, TSG, ITU, and TTA); this organization works together to develop and maintain technical specifications for 2G, 3G, 4G, LTE-Advanced, and 5G mobile networks. 3GPP also works together with other service providers (e.g., handset manufacturers, mobile network operators, software vendors, and telecommunications companies) to ensure the latest technological developments. 3GPP also works with other service providers (such as handset manufacturers, mobile network operators, software vendors, and telecommunications companies) to ensure that the latest technologies are developed.   I. History of 3GPP 3GPP was established in December 1998 as a result of the merger of 3GPP (Third Generation Partnership Project) and 3GPP2 (Third Generation Partnership Project 2). 3GPP is the successor to the GSM Technical Specification Group (GSM/GPRS) and the IMT-2000 Technical Specification Group (UMTS/HSPA). The merger was a response to the telecommunications industry's growing demand for global standards and the need for a single unified standards body.   II. 3GPP RESPONSIBILITIES 3GPP plays an important role in setting global standards for mobile communications and is responsible for the development of core networks, radio access networks, and a wide range of other related technologies. 3GPP standards provide the foundation for the development of new technologies such as 5G, IoT (Internet of Things), and mobile broadband. These standards also ensure interoperability and seamless roaming between different mobile networks around the world.   III.3GPP Technical Standards 3GPP has published technical standards from GSM to NR. The following are some of the key standards in mobile communications: GSM (Global System for Mobile Communications) EDGE (Enhanced Data Rate - GSM Evolution) UMTS (Universal Mobile Telecommunications System) HSPA (High Speed Packet Access) EPC (Evolved Packet Core) SAE (System Architecture Evolution) LTE (Long Term Evolution) NR (5G-New Radio) MBS (Mobile Broadcast Service) VoIP (Voice over IP) MBMS (Multimedia Broadcast Multicast Service) IMS (IP Multimedia Subsystem)   IV.3GPP and 5G The 3GPP standard regarding 5G is Release 16, which was released in March 2020. A number of new features and technologies have been introduced in Release 16 that will help to improve the performance and speed of 5G networks and improve the security of 5G communications. These features include support for wireless technologies such as Mobile Edge Computing (MEC) and network slicing, as well as improved Vehicular Networking (V2X) communication capabilities. In addition, Release 16 provides the necessary specifications and tools to support the deployment of 5G networks in a wide range of connectivity scenarios, from home broadband and enterprise applications to public safety and industrial IoT.

GTP is a data tunneling mechanism, which is used in 5G(NR) networks for the transmission of user data and signaling information between the user function (UPF) and the data network (DN).GTP (GPRS Tunneling Protocol) is used in 5G(NR) architectures as a communication protocol between different network elements for tunnel establishment in order to transmit data efficiently.The specific applications of the GTP tunneling protocol in 5G are presented as follows; i. User-plane communication:GTP tunnels are mainly associated with the user-plane, which handles the transmission of user data between UPF and data network (DN), whereas the tunneling of user data between the UPF and the data network is mainly associated with the user-plane, which handles the transmission of user data between UPF and the DN. GTP tunneling protocol specific applications are presented in the following aspects;   User-plane communication:GTP tunneling is mainly associated with the user-plane, which handles user data transmission between the UPF and the data network (DN), while the user-plane is responsible for forwarding user packets while ensuring efficient and reliable communication. Tunnel Establishment:GTP tunnels are established to encapsulate user packets and create a secure and efficient communication path between the UPF and the data network. GTP tunnels provide a logical connection for the seamless transfer of data. Application Versions:There are different versions of GTP in 5G(NR), including GTPv1-U (for the user-plane GTP V1) and GTPv1-C (for the control-plane version).GTPv1-U is usually associated with GTP tunnels in the user-plane. User-Plane Functions:The UPF is the key component in the 5G network architecture responsible for handling user-plane traffic.GTP tunnels connect the UPF to the data network and enable the UPF to forward user packets efficiently. Encapsulation and Decapsulation:At the source, GTP encapsulates user packets and adds headers to facilitate transmission through the GTP tunnel. At the destination, GTP decapsulates the packet and removes the added header to retrieve the original user data. Data Network:DN is the external network to which UPF is connected, which can include various external networks such as the Internet, public or private cloud services, and other communication networks. QoS and Billing:GTP tunnels can carry Quality of Service (QoS) information and billing-related details.QoS information ensures that user data is transmitted according to specified quality parameters, while billing information is critical for billing and accounting purposes. Context Bearer: GTP tunnels are associated with bearer contexts, which represent the logical connection between the user equipment (UE) and the UPF. Each bearer context corresponds to a specific GTP tunnel, allowing the network to manage multiple user data streams simultaneously. Efficient Data Transmission:GTP tunnels improve data transmission efficiency by providing a secure and dedicated path for user data. This is critical to providing the high data rates, low latency and reliable communications required for 5G networks. 3GPP standardization:GTP and its related functions (including GTP tunnels) are standardized by the 3GPP (Third Generation Partnership Project), which ensures consistency, interoperability, and compatibility between different 5G networks and providers.   GTP tunneling in 5G is the fundamental mechanism for establishing a secure and efficient communication path between user-plane functions and external data networks. By encapsulating and de-encapsulating user packets, it enables seamless data transmission while supporting key functions such as QoS and billing information. And its standardized nature ensures the reliability and interoperability of global 5G networks.  

1、Carrier aggregation (CA) is used to increase the bandwidth of a terminal (UE) for wireless communications by combining multiple carriers, where each aggregated carrier is called a component carrier (CC). carrier aggregation (CA) for 5G (NR) systems supports up to 16 contiguous and non-contiguous component carriers with different subcarrier intervals; carrier aggregation configurations include the type of carrier aggregation (in-band, contiguous or non-contiguous, or inter-band) The carrier aggregation configuration includes the type of carrier aggregation (in-band or non-contiguous or inter-band), the number of frequency bands and the bandwidth category.   2、The aggregation bandwidth category is identified in 5G(NR) with a series of alphabetical identifiers that define the minimum and maximum bandwidth and the number of component carriers. Among them: The 5G carrier aggregation CA supports up to 16 contiguous and non-contiguous component carriers with different SCSs; CA classes from A~O in FR1 (Release17); The maximum total bandwidth allowed by the CA in FR1 band is 400MHz; CA class from A~Q in FR2 (Release17) The maximum total bandwidth allowed for FR2 band CA is 800MHz; 3、FR1 carrier aggregation bandwidth Class A:Corresponds to Wireless Channel Carrier Aggregation 5G(NR) Configuration. The maximum BWChannel (carrier band) depends on the band number and the parameter set. The parameter set defines the SCS (Sub Carrier Spacing) between subcarriers.Class A belongs to all fallback groups and allows the UE to return to the basic configuration without aggregating carriers. Class B: corresponds to the aggregation of 2 radio channels to obtain a total bandwidth between 20 and 100 MHz; Class C: corresponds to the aggregation of 2 radio channels to obtain a total bandwidth between 20 and 100 MHz. Class C: corresponds to the aggregation of 2 radio channels to obtain a total bandwidth between 100 and 200 MHz; Class D: corresponds to the aggregation of 2 radio channels to obtain a total bandwidth between 20 and 100 MHz. Class D: the total bandwidth obtained by aggregating 3 wireless channels is between 200 and 300 MHz; Class E: the total bandwidth obtained by aggregating 4 wireless channels is between 300 and 400 MHz. ---- Classes C, D and E belong to the same fallback group 1. Class G: corresponds to the aggregation of 3 wireless channels to obtain a total bandwidth between 100~150MHz. Class H: corresponds to the aggregation of 4 radio channels with a total bandwidth between 150 and 200 MHz. Class I: corresponds to 5 radio channels aggregated into a total bandwidth between 200 and 250 MHz. Class J: corresponding to 6 radio channels aggregated into a total bandwidth between 250~300MHz Class K: corresponds to 7 wireless channels aggregated into a total bandwidth between 300~350MHz. Class L: corresponds to 8 wireless channels aggregated into a total bandwidth between 350~400MHz. -----G~L class belongs to the same fallback group2     4、FR2 Carrier Aggregation Bandwidth Class A: Corresponds to the No Carrier Aggregation 5G (NR) configuration. The maximum BWChannel (carrier band) depends on the band number and the parameter set. The parameter set defines the SCS (Sub-Carrier Spacing) between subcarriers; ---- Class A belongs to all fallback groups and allows the UE to return to the basic configuration without aggregating carriers. Class B: corresponds to 2 wireless channels aggregated with a total bandwidth between 400 and 800 MHz Class C:Corresponds to 2 wireless channels aggregated with total bandwidth between 800~1200MHz. ---- Class B is the fallback group of Class C, both belong to the same fallback group 1. Class D: corresponds to 2 wireless channels with aggregated total bandwidth between 200~400MHz. Class E: corresponds to 3 wireless channels with aggregated total bandwidth between 400 and 600 MHz. Class F: corresponds to 4 wireless channels aggregated with a total bandwidth between 600 and 800 MHz. ----D, E and F classes belong to the same fallback group 2. Class G: corresponds to 2 wireless channels aggregated with total bandwidth between 100~200 MHz Class H: corresponds to 3 wireless channels aggregated with total bandwidth between 200~300 MHz Class I: corresponds to 4 wireless channels with aggregated total bandwidth between 300 and 400 MHz. Class J: corresponding to 5 wireless channels aggregated total bandwidth between 400~500MHz Class K: corresponding to 6 wireless channels aggregated with a total bandwidth of 500~600MHz Class L: corresponds to 7 wireless channels aggregated with total bandwidth between 600~700MHz Class M: corresponds to 8 wireless channels aggregated with a total bandwidth between 700 and 800 MHz. ----G, H, I, J, K, L and M classes belong to the same fallback group 3.