Patent Description:
The wireless access nodes comprise Radio Units (RUs), Distributed Units (DUs) and Centralized Units (CUs). The RUs are mounted at elevation and have antennas, modulators, signal processor, and the like. The RUs are connected to the DUs which are usually nearby network computers. The DUs handle lower wireless network layers like the Physical Layer (PHY) and Media Access Control (MAC). The DUs are connected to the CUs which are larger computer centers that are closer to the network cores. The CUs handle higher wireless network layers like the Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP). The CUs are coupled to network elements in the network cores like Access and Mobility Management Functions (AMFs) and User Plane Functions (UPFs).

The wireless user devices and the RUs wirelessly exchange data. The RUs and the DUs exchange the data, and the DUs and the CUs exchange the data. The CUs and the UPFs exchange the data, and the UPFs exchange the data with external systems like the internet. The AMFs and the CUs exchange signaling to control the CUs, DUs, RUs, and wireless user devices. The SMFs and the UPFs exchange signaling to control the UPFs. The AMFs and SMFs control the Quality-of-Service (QoS) for the data sessions. The CUs control handovers of the wireless user devices among the RUs as the wireless user devices move about.

The wireless network cores have Network Repository Functions (NRFs) that serve the network functions like the SMFs, AMFs, and UPFs. The NRFs host network function registries that allow the network functions to discover and contact one another in an efficient and secure manner. The NRFs also serve event registrations and subscriptions where some network functions post events, and other network functions subscribe to the postings. Unfortunately, the NRFs and the CUs do not interact. Moreover, the network functions like the SMF and the UPF do not effectively optimize their data sessions based on handover events in the CUs. <NUM>rd Generation Partnership Project (3GPP), Technical Specification Group Services and System Aspects, "<NPL>), specifies the security architecture, i.e., the security features and the security mechanisms for the <NUM> System and the <NUM> Core, and the security procedures performed within the <NUM> System including the <NUM> Core and the <NUM> New Radio, including procedures for security algorithm selection in intra-gNB-CU handover/ intra-ng-eNB handover. 3GPP, Technical Specification Group Services and System Aspects, "<NPL>), investigates and identifies the security key issues for meeting the (ultra) low latency requirement and provides potential security requirements to address the identified security issues and to support URLLC services, including retaining AS security keys for redundant data transmission in user plane. 3GPP, Technical Specification Group Radio Access Network, "<NPL>), provides an overview and overall description of the NG-RAN and focuses on the radio interface protocol architecture of NR connected to 5GC, including state transitions and mobility aspects of security.

The present invention is set forth in the appended claims. A wireless communication system delivers a wireless data service to User Equipment (UE) responsive to a handover. In a Radio Access Network (RAN), a RAN Centralized Unit (CU) transfers a handover registration to a Network Repository Function (NRF). A Session Management Function (SMF) transfers a handover subscription for the UE to the NRF. The RAN CU detects a handover of the UE and responsively transfers a handover notice for the UE to the NRF. In response to the handover subscription for the UE from the SMF, the NRF transfers the handover notice for the UE to the SMF. The SMF modifies the wireless data service for the UE responsive to the handover notice for the UE. For example, the SMF may implement data encryption for the UE responsive to the handover.

<FIG> illustrates wireless communication network <NUM> to deliver a wireless data service to User Equipment (UE) <NUM> responsive to a handover. Wireless communication network <NUM> comprises wireless UE <NUM>, Radio Access Network (RAN) <NUM>, and wireless network core <NUM>. RAN <NUM> comprises Radio Units (RUs) <NUM>-<NUM>, Distributed Unit (DU) <NUM>, and Centralized Unit (CU) <NUM>. Wireless network core <NUM> comprises User Plane Function (UPF) <NUM>, Session Management Function (SMF) <NUM>, and Network Repository Function (NRF) <NUM>. The number of UEs, RANs, and cores that are depicted on <FIG> has been restricted for clarity, and wireless communication network <NUM> may comprise many more UEs, RANs, cores, and other functions.

Various examples of network operation and configuration are described herein. In some examples, CU <NUM> registers with NRF <NUM> to report handover events for RUs and UEs. Initially, UE <NUM> communicates with external systems over RU <NUM>, DU <NUM>, CU <NUM>, and UPF <NUM>. In network core <NUM>, SMF <NUM> controls UPF <NUM> to serve UE <NUM>, and in response, SMF <NUM> transfers a handover subscription for UE <NUM> to NRF <NUM>. Possibly due to UE mobility, RU <NUM> hands UE <NUM> over to RU <NUM>. After the handover, UE <NUM> communicates over RU <NUM>, DU <NUM>, CU <NUM>, and UPF <NUM>. CU <NUM> detects the handover of UE <NUM> to RU <NUM> and responsively transfers a handover notice for UE <NUM> and RU <NUM> to NRF <NUM>. In response to the handover subscription for UE <NUM>, NRF <NUM> transfers the handover notice for UE <NUM> and RU <NUM> to SMF <NUM>. SMF <NUM> modifies the wireless data service for UE <NUM> responsive to the handover notice to RU <NUM>. For example, SMF <NUM> may direct UPF <NUM> to encrypt user data for UE <NUM> after the handover to RU <NUM>. SMF <NUM> may initiate a policy change by modifying the Quality-of-Service (QoS) through a (Protocol Data Unit (PDU) session modification in another example.

Advantageously, NRF <NUM> effectively interacts with CU <NUM> and SMF <NUM> to establish handover event reporting for UE <NUM> from CU <NUM> to SMF <NUM>. Moreover, SMF <NUM> and UPF <NUM> efficiently optimize the data session for UE <NUM> based on handover events detected by CU <NUM>. SMF <NUM> may interact with a Policy Control Function (PCF) to implement new policies for UE <NUM> responsive to the handover to RU <NUM>. For example, the PCF may direct SMF <NUM> to burst user data for a time period. CU <NUM> may detect and report handovers for specific RUs or sets of RUs. Likewise, NRF <NUM> may report handovers for specific UEs or sets of UEs.

UE <NUM> and RUs <NUM>-<NUM> wirelessly communicate over wireless links using Radio Access Technologies (RATs) like Fifth Generation New Radio (5GNR), Long Term Evolution (LTE), Institute of Electrical and Electronic Engineers (IEEE) <NUM> (WIFI), Low-Power Wide Area Network (LP-WAN), and/or some other wireless protocol. The RATs use electromagnetic frequencies in the low-band, mid-band, high-band, or some other portion of the electromagnetic spectrum. RUs <NUM>-<NUM> and DU <NUM> communicate over fronthaul links. DU <NUM> and CU <NUM> communicate over mid-haul links. CU <NUM> and UPF <NUM> communicate over backhaul links. UPF <NUM> and external systems communicate over external links. These links use metallic links, glass fibers, radio channels, or some other communication media. The links use IEEE <NUM> (Ethernet), Time Division Multiplex (TDM), Data Over Cable System Interface Specification (DOCSIS), Internet Protocol (IP), General Packet Radio Service Transfer Protocol (GTP), 5GNR, LTE, WIFI, virtual switching, inter-processor communication, bus interfaces, and/or some other data communication protocols.

Although UE <NUM> is depicted as a smartphone, UE <NUM> might instead comprise a vehicle, sensor, robot, computer, or some other data appliance with wireless communication circuitry. RUs <NUM>-<NUM> are depicted as towers but RUs <NUM>-<NUM> may use other mounting structures or no mounting structure at all. RAN <NUM> may comprise gNodeBs, eNodeBs, NB-IoT access nodes, LP-WAN base stations, wireless relays, and/or some other wireless network transceivers. UE <NUM> and RUs <NUM>-<NUM> comprise antennas, amplifiers, filters, modulation, and analog/digital interfaces. UE <NUM>, RAN <NUM>, and network core <NUM> comprise microprocessors, software, memories, transceivers, bus circuitry, and the like. The microprocessors comprise Digital Signal Processors (DSP), Central Processing Units (CPU), Graphical Processing Units (GPU), Application-Specific Integrated Circuits (ASIC), and/or the like. The memories comprise Random Access Memory (RAM), flash circuitry, disk drives, and/or the like. The memories store software like operating systems, user applications, radio applications, and network functions. The microprocessors retrieve the software from the memories and execute the software to drive the operation of wireless communication network <NUM> as described herein.

<FIG> illustrates the operation of wireless communication network <NUM> to deliver the wireless data service to UE <NUM> responsive to the handover of UE <NUM>. This particular operation is exemplary and may vary in other examples. CU <NUM> registers with NRF <NUM> to report handover events for RU <NUM> (<NUM>). SMF <NUM> transfers a handover subscription for UE <NUM> to NRF <NUM> (<NUM>). When RU <NUM> accepts a handover (<NUM>), CU <NUM> detects the handover and transfers a handover notice for RU <NUM> to NRF <NUM> - and the handover notices identifies UE <NUM> (<NUM>). In response to the handover subscription for UE <NUM> and the handover notice, NRF <NUM> transfers the handover notice for UE <NUM> and RU <NUM> to SMF <NUM> (<NUM>). SMF <NUM> modifies the wireless data service for UE <NUM> responsive to the handover notice (<NUM>). For example, SMF <NUM> may interact with a Policy Control Function (PCF) to identify a new encryption policy for UE <NUM> responsive to a handover to RU <NUM>, and SMF <NUM> would then instruct UPF <NUM> to encrypt/decrypt user data for UE <NUM> per the new policy.

<FIG> illustrates the operation of wireless communication network <NUM> to deliver the wireless data service to UE <NUM> responsive to the handover of UE <NUM>. This particular operation is exemplary and may vary in other examples. In this example, Access and Mobility Management Function (AMF) <NUM> and Policy Control Function (PCF) <NUM> are included but are not required in other examples.

CU <NUM> registers with NRF <NUM> to report handover events for RU <NUM>. UE <NUM> transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to DU <NUM>. DU <NUM> transfers corresponding attachment signaling to CU <NUM>. CU <NUM> transfers corresponding attachment signaling to AMF <NUM>. AMF <NUM> and SMF <NUM> exchange UE context and SMF <NUM> typically adds UPF selections and network addresses. SMF <NUM> queries PCF <NUM> for policies for UE <NUM>, and PCF <NUM> returns policies for UE <NUM> to SMF <NUM>. SMF <NUM> and AMF <NUM> process the policies to further develop the UE context for UE <NUM> like adding Quality-of-Service (QoS), network names, and network slices. In response to the UE context for UE <NUM>, SMF <NUM> subscribes to handover events for UE <NUM> from NRF <NUM>. SMF <NUM> transfers UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers UE context for UE <NUM> to CU <NUM>. CU <NUM> transfers UE context for UE <NUM> to DU <NUM> which transfers UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers UE context to UE <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the UE context. RU <NUM> and DU <NUM> exchange the data responsive to the UE context. DU <NUM> and CU <NUM> exchange the data responsive to the UE context. CU <NUM> and UPF <NUM> exchange the data responsive to the UE context. UPF <NUM> exchanges the data with external systems responsive to the UE context.

In response to UE mobility, RU <NUM> hands UE <NUM> over to RU <NUM>. UE <NUM> now transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to DU <NUM>. DU <NUM> transfers corresponding attachment signaling to CU <NUM>. CU <NUM> detects the handover for RU <NUM> and transfers a corresponding handover event to NRF <NUM>. In response to the handover subscription for UE <NUM>, NRF <NUM> transfers a corresponding handover event notice for UE <NUM> and RU <NUM> to SMF <NUM>. SMF <NUM> transfers a corresponding handover notice to PCF <NUM>. PCF <NUM> identifies new policies for UE <NUM> after the handover to RU <NUM> and transfers the new policies to SMF <NUM>. SMF <NUM> processes the new policies to develop new UE context for UE <NUM> like a new QoS level. AMF <NUM> and SMF <NUM> exchange new UE context. AMF <NUM> transfers new UE context for UE <NUM> to CU <NUM>. CU <NUM> transfers new UE context for UE <NUM> to DU <NUM> which transfers new UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers new UE context like the QoS level to UE <NUM>. SMF <NUM> transfers new UE context for UE <NUM> - like a new QoS level - to UPF <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the new UE context. RU <NUM> and DU <NUM> exchange the data responsive to the new UE context. DU <NUM> and CU <NUM> exchange the data responsive to the new UE context. CU <NUM> and UPF <NUM> exchange the data responsive to the new UE context. UPF <NUM> exchanges the data with external systems responsive to the new UE context.

<FIG> illustrates Fifth Generation (<NUM>) wireless communication network <NUM> to deliver a wireless data service responsive to a UE handover. <NUM> wireless communication network <NUM> comprises UE <NUM>, Radio Access Network (RAN) <NUM>, and network core <NUM>. RAN <NUM> comprises RAN Radio Units (RUs) <NUM>-<NUM>, RAN Distributed Unit (DU) <NUM>, and RAN Centralized Unit (CU) <NUM>. Network core <NUM> comprises User Plane Function (UPF) <NUM>, Session Management Function (SMF) <NUM>, Network Repository Function (NRF) <NUM>, Access and Mobility Management Function (AMF) <NUM>, and Policy Control Function (PCF) <NUM>.

RAN CU <NUM> registers with NRF <NUM> to report handover events for RUs <NUM>-<NUM> on a per-UE basis. UE <NUM> transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to DU <NUM>, and DU <NUM> transfers corresponding attachment signaling to CU <NUM>. CU <NUM> transfers corresponding attachment signaling to AMF <NUM>. AMF <NUM> authenticates UE <NUM> and selects network names and slices for UE <NUM>. AMF <NUM> queries PCF <NUM> for policies for UE <NUM>, and PCF <NUM> returns policies for UE <NUM> to AMF <NUM>. AMF <NUM> processes the policies to develop UE context for UE <NUM>. AMF <NUM> and SMF <NUM> exchange UE context and SMF <NUM> typically adds UPF selections and network addresses. In response to the UE context for UE <NUM>, SMF <NUM> subscribes to handover events for UE <NUM> from NRF <NUM>. In response to the CU <NUM> registration for RU <NUM> handover reporting, NRF <NUM> requests handover events for UE <NUM> from CU <NUM>.

SMF <NUM> transfers UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers UE context for UE <NUM> to CU <NUM>. CU <NUM> transfers UE context for UE <NUM> to DU <NUM> which transfers UE context for UE <NUM> to RU <NUM>. RU <NUM> transfers UE context to UE <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the UE context. RU <NUM> and DU <NUM> exchange the data responsive to the UE context. DU <NUM> and CU <NUM> exchange the data responsive to the UE context. CU <NUM> and UPF <NUM> exchange the data responsive to the UE context. UPF <NUM> exchanges the data with external systems responsive to the UE context.

In response to UE mobility, RU <NUM> hands UE <NUM> over to RU <NUM>. UE <NUM> now transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to DU <NUM>. DU <NUM> transfers corresponding attachment signaling to CU <NUM>. CU <NUM> detects the handover for UE <NUM> from RU <NUM> to RU <NUM>. In response to the NRF registration and UE request, CU <NUM> transfers a corresponding handover event for UE <NUM> from RU <NUM> to RU <NUM> to NRF <NUM>. In response to the handover subscription for UE <NUM>, NRF <NUM> transfers a corresponding handover event notice (UE <NUM> from RU <NUM> to RU <NUM>) to SMF <NUM>. SMF <NUM> transfers a corresponding handover notice (UE <NUM> from RU <NUM> to RU <NUM>) to PCF <NUM>. PCF <NUM> identifies new policies for UE <NUM> after the handover from RU <NUM> to RU <NUM> and transfers the new policies for UE <NUM> to SMF <NUM>. SMF <NUM> processes the new policies to develop new UE context for UE <NUM> like new QoS signaling.

SMF <NUM> transfers new UE context for UE <NUM> to UPF <NUM>. SMF <NUM> and AMF <NUM> exchange new UE context for UE <NUM>. AMF <NUM> transfers new UE context for UE <NUM> to CU <NUM>. CU <NUM> transfers new UE context for UE <NUM> to DU <NUM> which transfers new UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers new UE context for UE <NUM> to UE <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the new UE context. RU <NUM> and DU <NUM> exchange the data responsive to the new UE context. DU <NUM> and CU <NUM> exchange the data responsive to the new UE context. CU <NUM> and UPF <NUM> exchange the data responsive to the new UE context. UPF <NUM> exchanges the data with external systems responsive to the new UE context. For example, UE <NUM> and UPF <NUM> may start downlink encryption for a downlink data burst in response to the handover to RU <NUM>.

<FIG> illustrates Radio Access Network (RAN) <NUM> in <NUM> wireless communication network <NUM> that delivers the wireless data service responsive to the UE handover. RAN <NUM> comprises an example of RAN <NUM> on <FIG>, although RAN <NUM> may differ. RAN <NUM> comprises Radio Units (RUs) <NUM>-<NUM>, Distributed Unit (DU) <NUM>, and Centralized Unit (CU) <NUM>. RUs <NUM>-<NUM> comprise antennas, amplifiers, filters, modulation, analog-to-digital interfaces, DSP, memory, and transceivers (XCVRs) that are coupled over bus circuitry. DU <NUM> comprises memory, CPU, and transceivers that are coupled over bus circuitry. The memory in DU <NUM> stores an operating system and 5GNR network applications like Physical Layer (PHY), Media Access Control (MAC), and Radio Link Control (RLC). CU <NUM> comprises memory, CPU, and transceivers that are coupled over bus circuitry. The memory in CU <NUM> stores an operating system and network applications like Packet Data Convergence Protocol (PDCP), Service Data Adaptation Protocol (SDAP), and Radio Resource Control (RRC).

In DU <NUM>, RLC functions comprise Automatic Repeat Request (ARQ), sequence numbering and resequencing, segmentation and resegmentation. MAC functions comprise buffer status, power control, channel quality, Hybrid Automatic Repeat Request (HARQ), user identification, random access, user scheduling, and QoS. PHY functions comprise packet formation/deformation, guard-insertion/guard-deletion, parsing/de-parsing, control insertion/removal, interleaving/de-interleaving, Forward Error Correction (FEC) encoding/decoding, channel coding/decoding, channel estimation/equalization, and rate matching/de-matching, scrambling/descrambling, modulation mapping/de-mapping, layer mapping/de-mapping, precoding, Resource Element (RE) mapping/de-mapping, Fast Fourier Transforms (FFTs)/Inverse FFTs (IFFTs), and Discrete Fourier Transforms (DFTs)/Inverse DFTs (IDFTs).

In CU <NUM>, PDCP functions include security ciphering, header compression and decompression, sequence numbering and re-sequencing, de-duplication. SDAP functions include QoS marking and flow control. RRC functions include authentication, security, handover control, status reporting, QoS, network broadcasts and pages, and network selection.

UE <NUM> is wirelessly coupled to the antennas in RUs <NUM>-<NUM> over 5GNR links. Transceivers in RUs <NUM>-<NUM> are coupled to transceivers in DU <NUM> over fronthaul links like enhanced Common Public Radio Interface (eCPRI). Transceivers in DU <NUM> are coupled to transceivers in CU <NUM> over mid-haul links. Transceivers in CU <NUM> are coupled to network core <NUM> over backhaul links. The DSP and CPU in RUs <NUM>-<NUM>, DU <NUM>, and CU <NUM> execute their operating systems, radio applications, PHY, MAC, RLC, PDCP, SDAP, and RRC to exchange 5GNR signals with UE <NUM>, exchange 5GC signaling and data with network core <NUM>, and exchange X2 signaling and data with other CUs.

In RUs <NUM>-<NUM>, the antennas receive wireless 5GNR signals from UE <NUM> that transport uplink 5GNR signaling and data. The antennas transfer corresponding electrical uplink signals through duplexers to the amplifiers. The amplifiers boost the electrical uplink signals for filters which attenuate unwanted energy. Demodulators down-convert the filtered uplink signals from their carrier frequency. The analog/digital interfaces convert the demodulated analog uplink signals into digital uplink signals for the DSPs. The DSPs recover uplink 5GNR symbols from the uplink digital signals and transfer the uplink 5GNR symbols to DU <NUM>. In DU <NUM>, the CPU executes the network applications (PHY, MAC, and RLC) to process the uplink 5GNR symbols and recover the uplink 5GNR signaling and data. The RLC in DU <NUM> transfers UL data units to the PDCP in CU <NUM>. In CU <NUM>, the CPU executes the network applications (PDCP, SDAP, and RRC) to process the uplink data units and recover the uplink 5GNR signaling and data. The RRC processes the uplink 5GNR signaling, downlink N2 signaling, and X2 signaling to generate new downlink 5GNR signaling, new uplink N2 signaling, and new X2 signaling. The RRC transfers the new uplink N2 signaling to network core <NUM> and the X2 signaling to other CUs. The SDAP exchanges N3 data to network core <NUM>.

In CU <NUM>, the RRC receives N2 signaling from network core <NUM> and X2 signaling from the other CUs. The SDAP receives downlink data from network core <NUM> and X2 data from other CUs. The 5GNR network applications (RRC, SDAP, PDCP) process the new downlink 5GNR signaling and data to generate corresponding downlink data units. The PDCP in CU <NUM> transfers the downlink data units to the RLC in DU <NUM>. The 5GNR network applications (RLC, MAC, PHY) in DU <NUM> process the downlink data units to generate corresponding 5GNR symbols. DU <NUM> transfers the downlink 5GNR symbols to RUs <NUM>-<NUM>. In RUs <NUM>-<NUM>, the DSP processes the downlink 5GNR symbols to generate corresponding digital signals for the analog-to-digital interfaces. The analog-to-digital interfaces convert the digital signals into analog signals for modulation. Modulation up-converts the analog signals to their carrier frequency. The amplifiers boost the modulated signals for the filters which attenuate unwanted out-of-band energy. The filters transfer the filtered electrical signals through duplexers to the antennas. The filtered electrical signals drive the antennas to emit corresponding wireless signals to 5GNR UE <NUM> that transport the downlink 5GNR signaling and data.

The RRC in CU <NUM> registers with NRF <NUM> in network core <NUM> to report handover events for RUs <NUM>-<NUM> on a per-UE basis. UE <NUM> transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to the PHY in DU <NUM>. The PHY interacts with the MAC which interacts with the RLC. The RLC in DU <NUM> transfers corresponding attachment signaling to the PDCP in CU <NUM>. The PDCP interacts with the RRC and the SDAP. The RRC in CU <NUM> transfers corresponding N2 signaling for UE <NUM> to AMF <NUM> in network core <NUM>. The SDAP in CU <NUM> exchanges N3 data for UE <NUM> with UPF <NUM> in network core <NUM>. The RRC in CU <NUM> receives a request for handover events for UE <NUM> from NRF <NUM> in network core <NUM>.

The RRC in CU <NUM> receives UE context for UE <NUM> from AMF <NUM> in network core <NUM>. The AMF interacts with the PDCP. The PDCP in CU <NUM> transfers UE context for UE <NUM> to the RLC in DU <NUM>, and the RLC interacts with the MAC which interacts with the PHY. The PHY in DU <NUM> transfers UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers UE context to UE <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the UE context. RU <NUM> and the PHY in DU <NUM> exchange the data responsive to the UE context. The PHY interacts with the MAC which interacts with the RLC. The RLC in DU <NUM> and the PDCP in CU <NUM> exchange the data responsive to the UE context. The PDCP interacts with the SDAP. The SDAP in CU <NUM> and UPF <NUM> in network core <NUM> exchange the data responsive to the UE context.

In response to UE mobility, the RRC in CU <NUM> hands UE <NUM> over from RU <NUM> to RU <NUM>. UE <NUM> now transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to the PHY in DU <NUM>. The PHY interacts with the MAC which interacts with the RLC. The RLC in DU <NUM> transfers corresponding attachment signaling to the PDCP in CU <NUM>. The PDCP interacts with the RRC. In response to the NRF registration and the NRF request, the RRC in CU <NUM> transfers a corresponding handover event (UE <NUM> from RU <NUM> to RU <NUM>) to NRF <NUM>. The RRC in CU <NUM> receives new UE context for UE <NUM> from AMF <NUM> in network core <NUM>. The RRC interacts with the PDCP. The PDCP in CU <NUM> transfers new UE context for UE <NUM> to the RLC in DU <NUM>. The RLC interacts with the MAC which interacts with the PHY. The PHY in DU <NUM> transfers new UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers new UE context for UE <NUM> to UE <NUM>. UE <NUM> and RU <NUM> wirelessly exchange data responsive to the new UE context. RU <NUM> and the PHY in DU <NUM> exchange the data responsive to the new UE context. The PHY interacts with the MAC which interacts with the RLC. The RLC in DU <NUM> and the PDCP in CU <NUM> exchange the data responsive to the new UE context. The PDCP interacts with the SDAP. The SDAP in CU <NUM> and UPF <NUM> in network core <NUM> exchange the data responsive to the new UE context.

<FIG> illustrates wireless network core <NUM> in <NUM> wireless communication network <NUM> that delivers the wireless data service responsive to the UE handover. Wireless network core <NUM> comprises an example of network core <NUM> on <FIG>, although core <NUM> may differ. Wireless network core <NUM> comprises Network Function Virtualization Infrastructure (NFVI) hardware <NUM>, NFVI hardware drivers <NUM>, NFVI operating systems <NUM>, NFVI virtual layer <NUM>, and NFVI Virtual Network Functions (VNFs) <NUM>. NFVI hardware <NUM> comprises Network Interface Cards (NICs), CPU, RAM, Flash/Disk Drives (DRIVE), and Data Switches (SW). NFVI hardware drivers <NUM> comprise software that is resident in the NIC, CPU, RAM, DRIVE, and SW. NFVI operating systems <NUM> comprise kernels, modules, applications, containers, hypervisors, and the like. NFVI virtual layer <NUM> comprises vNIC, vCPU, vRAM, vDRIVE, and vSW. NFVI VNFs <NUM> comprise UPF <NUM>, SMF <NUM>, NRF <NUM>, AMF <NUM>, and PCF <NUM>. Other VNFs like Authentication Server Function (AUSF), Unified Data Manager (UDM), Network Exposure Function (NEF), Network Slice Selection Function (NSSF), are typically present but are omitted for clarity. Wireless network core <NUM> may be located at a single site or be distributed across multiple geographic locations. The NIC are coupled to CU <NUM> in RAN <NUM> and external systems. NFVI hardware <NUM> executes NFVI hardware drivers <NUM>, NFVI operating systems <NUM>, NFVI virtual layer <NUM>, and NFVI VNFs <NUM> to serve UE <NUM> over RAN <NUM>.

<FIG> further illustrates wireless network core <NUM> in <NUM> wireless communication network <NUM> that delivers the wireless data service responsive to the UE handover. UPF <NUM> performs packet routing & forwarding, packet inspection, QoS handling, PDU interconnection, and mobility anchoring. SMF <NUM> performs session establishment/management, network address allocation, N1 termination, downlink data notification, and traffic steering and routing. NRF <NUM> performs network function authentication and authorization, selection, security, and event registration/subscriptions. AMF <NUM> performs N2/N1 termination, N1 ciphering & integrity protection, UE registration, SMF/PCF selection, UE connection/mobility management, UE authentication and authorization, UE security management, and tracking area updates. PCF <NUM> performs policy framework implementation for slices and roaming, policy control-plane distribution, and handover policy insertion. Although not shown for clarity, an AUSF performs UE authentication with Authentication and Key Agreement (AKA) credentials and handles UE authorizations. A UDM handles UE context, UE subscription data, and UE authentication keys. An NSSF performs network slice selection per UE, network slice authorization per UE, and AMF reselection per UE.

In operation, NRF <NUM> receives a registration from the RRC in CU <NUM> to report handover events for RUs <NUM>-<NUM> on a per-UE basis. AMF <NUM> receives N2 attachment signaling from CU <NUM> for UE <NUM>. AMF <NUM> authenticates UE <NUM> and selects network names and slices for UE <NUM>. AMF <NUM> queries PCF <NUM> for policies for UE <NUM>, and PCF <NUM> returns policies for UE <NUM> to AMF <NUM>. AMF <NUM> processes the policies to develop UE context for UE <NUM> like QoS parameters. AMF <NUM> and SMF <NUM> exchange UE context, and SMF <NUM> adds a UPF <NUM> selection and network addresses. In response to the UE context for UE <NUM>, SMF <NUM> subscribes to handover events for UE <NUM> from NRF <NUM>. In response to the CU <NUM> registration for handover reporting, NRF <NUM> requests handover events for UE <NUM> from CU <NUM>. SMF <NUM> transfers UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers UE context for UE <NUM> to the RRC in CU <NUM>. The SDAP in CU <NUM> and UPF <NUM> exchange the data responsive to the UE context. UPF <NUM> exchanges the data with external systems responsive to the UE context.

The RRC in CU <NUM> detects the handover for UE <NUM> from RU <NUM> to RU <NUM>. In response to the NRF registration and request, the RRC in CU <NUM> transfers a corresponding handover event to NRF <NUM> that characterizes the handover of UE <NUM> from RU <NUM> to RU <NUM>. In response to the handover subscription for UE <NUM>, NRF <NUM> transfers a corresponding handover event notice for UE <NUM> to SMF <NUM>. SMF <NUM> transfers a corresponding handover notice to PCF <NUM>. PCF <NUM> identifies new policies for UE <NUM> responsive to the handover of UE <NUM> from RU <NUM> to RU <NUM>. PCF <NUM> transfers the new policies for UE <NUM> to SMF <NUM>. SMF <NUM> processes the new policies to develop new UE context for UE <NUM> like new QoS signaling. SMF <NUM> and AMF <NUM> exchange new UE context. SMF <NUM> transfers new UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers new UE context for UE <NUM> to the RRC in CU <NUM>. The SDAP in CU <NUM> and UPF <NUM> exchange the data responsive to the new UE context. UPF <NUM> exchanges the data with external systems responsive to the new UE context.

<FIG> illustrates UE <NUM> that receives the wireless data service from <NUM> wireless communication network <NUM> responsive to the UE handover. UE <NUM> comprises an example of UE <NUM>, although UE <NUM> may differ. UE <NUM> comprises 5GNR radio <NUM> and user circuitry <NUM>. 5GNR radio <NUM> comprises antennas, amplifiers, filters, modulation, analog-to-digital interfaces, DSP, memory, and transceivers that are coupled over bus circuitry. User circuitry <NUM> comprises memory, CPU, user interfaces, and transceivers that are coupled over bus circuitry. The memory in user circuitry <NUM> stores an operating system, user applications (USER), and 5GNR network applications for PHY, MAC, RLC, PDCP, SDAP, and RRC. The antennas in 5GNR radio <NUM> are wirelessly coupled to RAN <NUM> over 5GNR links. Transceivers in 5GNR radio <NUM> are coupled to a transceiver in user circuitry <NUM>. A transceiver in user circuitry <NUM> is typically coupled to the user interfaces like displays, controllers, memory, and the like. The CPU in user circuitry <NUM> executes the operating system, PHY, MAC, RLC, PDCP, SDAP, and RRC to exchange 5GNR signaling and data with RAN <NUM> over 5GNR radio <NUM>.

<FIG> illustrates the operation of <NUM> wireless communication network <NUM> to deliver the wireless data service responsive to the UE handover. The operation is exemplary and may differ in other examples. The RRC in CU <NUM> registers with NRF <NUM> to report handover events for RUs <NUM>-<NUM> on a per-UE basis. The RRC in UE <NUM> transfers attachment signaling to RU <NUM> over the PDCP, RLC, MAC, and PHY in UE <NUM>. RU <NUM> transfers corresponding attachment signaling to the PHY in DU <NUM> which interacts with the MAC which interacts with the RLC. The RLC in DU <NUM> transfers corresponding attachment signaling to the PDCP in CU <NUM> which interacts with the RRC. The RRC in CU <NUM> transfers corresponding attachment signaling to AMF <NUM>.

AMF <NUM> authenticates UE <NUM> and selects network names and slices for UE <NUM>. AMF <NUM> queries PCF <NUM> for policies for UE <NUM>, and PCF <NUM> returns policies for UE <NUM> to AMF <NUM>. AMF <NUM> processes the policies to develop UE context for UE <NUM> like QoS levels. AMF <NUM> and SMF <NUM> exchange UE context, and SMF <NUM> adds a UPF <NUM> selection and network addresses. In response to the UE context for UE <NUM>, SMF <NUM> subscribes to handover events for UE <NUM> from NRF <NUM>. In response to the CU <NUM> registration for handover reporting, NRF <NUM> requests handover events for UE <NUM> from the RRC in CU <NUM>.

SMF <NUM> transfers UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers UE context for UE <NUM> to the RRC in CU <NUM>. The RRC in CU <NUM> transfers UE context for UE <NUM> to the PDCP which transfers UE context to the RLC in DU <NUM>. The RLC in DU <NUM> interacts with the MAC which interacts with the PHY. The PHY in DU <NUM> transfers UE context for UE <NUM> to RU <NUM>. RU <NUM> wirelessly transfers UE context to the RRC in UE <NUM> over the PHY, MAC, RLC, and PDCP in UE <NUM>.

The SDAP in UE <NUM> and RU <NUM> wirelessly exchange data responsive to the UE context over the PDCP, RLC, MAC, and PHY in UE <NUM>. RU <NUM> and the PHY in DU <NUM> exchange the data responsive to the UE context, and the PHY exchanges the data with the MAC which exchanges the data with the RLC. The RLC in DU <NUM> and the PDCP on CU <NUM> exchange the data responsive to the UE context. In CU <NUM>, the PDCP in exchanges the data with the SDAP, and the SDAP exchange the data with UPF <NUM> responsive to the UE context. UPF <NUM> exchanges the data with external systems responsive to the UE context. In some examples, the SDAP is omitted from CU <NUM>, and the PDCP in exchanges the N3 data with UPF <NUM> responsive to the UE context.

In response to UE mobility, RU <NUM> hands UE <NUM> over to RU <NUM> under RRC control from CU <NUM>. UE <NUM> now transfers attachment signaling to RU <NUM>. RU <NUM> transfers corresponding attachment signaling to the PHY in DU <NUM> which transfers attachment signaling to the MAC which transfers attachment signaling to the RLC. The RLC in DU <NUM> transfers corresponding attachment signaling to the PDCP in CU <NUM> which transfers corresponding attachment signaling to the RRC. The RRC in CU <NUM> detects the handover for UE <NUM> from RU <NUM> to RU <NUM>. In response to the NRF registration and NRF request for UE <NUM>, the RRC in CU <NUM> transfers a corresponding handover event to NRF <NUM> that characterizes the handover of UE <NUM> from RU <NUM> to RU <NUM>. In response to the handover subscription for UE <NUM>, NRF <NUM> transfers a corresponding handover event notice for UE <NUM> to SMF <NUM>. SMF <NUM> transfers a corresponding handover notice to PCF <NUM>. PCF <NUM> identifies new policies for UE <NUM> in response to the handover from RU <NUM> to RU <NUM>. PCF <NUM> transfers the new policies for UE <NUM> to SMF <NUM>. SMF <NUM> processes the new policies to develop new UE context for UE <NUM>.

SMF <NUM> and AMF <NUM> exchange new UE context. SMF <NUM> transfers new UE context for UE <NUM> to UPF <NUM>. AMF <NUM> transfers new UE context for UE <NUM> to the RRC in CU <NUM>. The RRC in CU <NUM> transfers new UE context for UE <NUM> to the PDCP which transfers new UE context to the RLC in DU <NUM>. The RLC in DU <NUM> transfers new UE context for UE <NUM> to the MAC which transfers new UE context to the PHY. The PHY transfers new UE context to RU <NUM>. RU <NUM> wirelessly transfers new UE context for UE <NUM> to the RRC in UE <NUM> over the PHY, MAC, RLC, and PDCP in UE <NUM>. The SDAP in UE <NUM> and RU <NUM> wirelessly exchange data responsive to the new UE context over the PDCP, RLC, MAC, and PHY in UE <NUM>. RU <NUM> and the PHY in DU <NUM> exchange the data responsive to the new UE context. The PHY exchanges the data with the MAC which exchanges the data with the RLC. The RLC in DU <NUM> and the PDCP in CU <NUM> exchange the data responsive to the new UE context. The PDCP exchanges the data with the SDAP. The SDAP in CU <NUM> and UPF <NUM> exchange the data responsive to the new UE context. UPF <NUM> exchanges the data with external systems responsive to the new UE context. In some examples, the SDAP is omitted from CU <NUM>, and the PDCP exchanges N3 data with UPF <NUM> responsive to the UE context.

The wireless data network circuitry described above comprises computer hardware and software that form special-purpose network circuitry to deliver to wireless data service responsive to UE handovers. The computer hardware comprises processing circuitry like CPUs, DSPs, GPUs, transceivers, bus circuitry, and memory. To form these computer hardware structures, semiconductors like silicon or germanium are positively and negatively doped to form transistors. The doping comprises ions like boron or phosphorus that are embedded within the semiconductor material. The transistors and other electronic structures like capacitors and resistors are arranged and metallically connected within the semiconductor to form devices like logic circuity and storage registers. The logic circuitry and storage registers are arranged to form larger structures like control units, logic units, and Random-Access Memory (RAM). In turn, the control units, logic units, and RAM are metallically connected to form CPUs, DSPs, GPUs, transceivers, bus circuitry, and memory.

In the computer hardware, the control units drive data between the RAM and the logic units, and the logic units operate on the data. The control units also drive interactions with external memory like flash drives, disk drives, and the like. The computer hardware executes machine-level software to control and move data by driving machine-level inputs like voltages and currents to the control units, logic units, and RAM. The machine-level software is typically compiled from higher-level software programs. The higher-level software programs comprise operating systems, utilities, user applications, and the like. Both the higher-level software programs and their compiled machine-level software are stored in memory and retrieved for compilation and execution. On power-up, the computer hardware automatically executes physically-embedded machine-level software that drives the compilation and execution of the other computer software components which then assert control. Due to this automated execution, the presence of the higher-level software in memory physically changes the structure of the computer hardware machines into special-purpose network circuitry to deliver to wireless data service responsive to UE handovers.

Claim 1:
A method of operating a wireless communication system to deliver a wireless data service to User Equipment, UE, responsive to a handover of the UE, the method comprising:
a Radio Access Network Centralized Unit, RAN CU, transferring (<NUM>) a handover registration to a Network Repository Function, NRF;
a Session Management Function, SMF, transferring (<NUM>) a handover subscription for the UE to the NRF;
the NRF receiving the handover registration and the handover subscription;
the RAN CU detecting a handover (<NUM>) of the UE and responsively transferring a handover notice for the UE to the NRF;
the NRF receiving (<NUM>) the handover notice for the UE, and in response to the handover subscription for the UE from the SMF, transferring the handover notice for the UE to the SMF; and
the SMF modifying (<NUM>) the wireless data service for the UE responsive to the handover notice for the UE.