Synchronized data communications over multiple wireless links and access nodes

In a wireless access node, a Protocol Data Convergence Protocol (PDCP) separates data into direct data and indirect data. The wireless access node wirelessly transfers the direct data to User Equipment (UE) and transfers the indirect data to a wireless support node. The wireless support node wirelessly transfers the indirect data to the UE. The PDCP estimates a transmission time difference between the direct data and the indirect data. The PDCP separates additional data into direct data and indirect data. The PDCP delays the additional direct and/or indirect data based on the time difference to synchronize delivery. The wireless access node wirelessly transfers the direct data to the UE and transfers the indirect data to the wireless support node. The wireless support node wirelessly transfers the indirect data to the UE.

TECHNICAL BACKGROUND

Wireless communication networks provide wireless data services to wireless user devices. Exemplary wireless data services include machine-control, Internet-access, media-streaming, and social-networking. Exemplary wireless user devices comprise phones, computers, vehicles, robots, and sensors. The wireless communication networks have wireless access nodes that exchange wireless signals with the wireless user devices using wireless network protocols. Exemplary wireless network protocols include Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WIFI), Long Term Evolution (LTE), Fifth Generation New Radio (5GNR), and Low-Power Wide Area Network (LP-WAN). In some examples, both LTE and 5GNR networks serve the same wireless user device at the same time with an integrated data service called dual-connectivity.

The wireless communication networks receive user data from external systems for delivery to the wireless user devices. The wireless communication networks transfer the user data to the wireless access nodes. For dual-connectivity, Packet Data Convergence Protocols (PDCPs) in the wireless access nodes separate the user data into a direct data portion and an indirect data portion. The wireless access nodes wirelessly transfer the direct data portion to the wireless user devices. The wireless access nodes transfer the indirect data portion to wireless support nodes. The wireless support nodes wirelessly transfer the indirect data portion to the wireless user devices. Unfortunately, the delivery of the indirect data portion usually takes longer than the delivery of the direct data portion. The wireless user devices receive their direct and indirect data portions in an unsynchronized manner due to the time difference between the direct delivery and the indirect delivery. The wireless user devices may have to re-sequence or request a re-transmission of their unsynchronized user data.

TECHNICAL OVERVIEW

In a wireless access node, a Protocol Data Convergence Protocol (PDCP) separates user data into direct data and indirect data. The wireless access node wirelessly transfers the direct data to User Equipment (UE) and transfers the indirect data to a wireless support node. The wireless support node wirelessly transfers the indirect data to the UE. The PDCP estimates a transmission time difference between the direct data and the indirect data. The PDCP separates additional user data into direct data and indirect data. The PDCP delays the additional direct and/or indirect data based on the time difference to synchronize delivery to the UE. The wireless access node wirelessly transfers the direct data to the UE and transfers the indirect data to the wireless support node. The wireless support node wirelessly transfers the indirect data to the UE.

DETAILED DESCRIPTION

FIG. 1illustrates wireless communication network100to serve wireless User Equipment (UEs)111-113with a synchronized data service over wireless links101-106and wireless nodes121-122. Wireless communication network100comprises wireless UEs111-113, wireless access node121, wireless support node122, and network elements130. Although UEs111-113are depicted as smartphones operated by humans, UEs111-113might instead comprise wearable computers, robots, vehicles, or some other data appliances with wireless communication circuitry that may or may not be operated by humans. Wireless nodes121-122are depicted as radio towers, but nodes121-122may use other mounting structures or no mounting structure at all. Wireless access node121executes Protocol Data Convergence Protocol (PDCP)123.

Various examples of network operation and configuration are described herein. In one example, network elements130receive user data over external link109and transfer the user data to wireless access node121over network link108for delivery to wireless UEs111-113. Wireless access node121receives the user data over network link108. Wireless access node121transfers the user data to PDCP123. PDCP123separates the user data into a direct portion and an indirect portion. The direct portion will be transferred directly to wireless UEs111-113from wireless access node121, and the indirect portion will be transferred indirectly to wireless UEs111-113over wireless support node122. PDCP123routes the direct portion toward wireless UEs111-113and routes the indirect portion toward wireless support node122. Wireless access node121receives the routed user data from PDCP123. Wireless access node121wirelessly transfers the direct portion to wireless UEs111-113over wireless links101-103. Wireless access node121transfers the indirect portion to wireless support node122over network links107. Wireless support node122receives the indirect data over network links107and wirelessly transfers the indirect data to wireless UEs111-113over wireless links104-106.

In wireless access node121, PDCP123estimates a transmission time difference between the delivery of the direct data and the delivery of the indirect data. The transmission time may comprise the elapsed time from data arrival over external link109to data transfer over wireless links101-106. The transmission time may comprise the elapsed time from data arrival over network link108to data transfer over wireless links101-106. PDCP123may estimate the transmission time difference based on metrics like data throughput and buffer fill. For example, PDCP123may multiply the data throughput for wireless access node121by the buffer fill for wireless access node121to estimate a time amount for direct delivery. Likewise, PDCP123may multiply the data throughput for wireless support node122by the buffer fill for wireless support node122to estimate another time amount for indirect delivery. PDCP123could estimate the transmission time difference by based on the difference between these two time amounts.

Network elements130receive additional user data over external links109and transfer the additional data to wireless access node121over network links108for delivery to wireless UEs111-113. Wireless access node121receives the additional data over network links108and transfers the additional data to PDCP123. PDCP123separates the additional data into a direct portion and an indirect portion. PDCP123delays the direct portion and/or the indirect portion based on the estimated transmission time difference to synchronize delivery of the additional user data to UEs111-113over wireless nodes121-122. Typically, the direct transmission time is shorter, so the direct portion is delayed by the estimated transmission time difference. PDCP123routes the indirect portion toward wireless support node122, and wireless access node121transfers the indirect portion to wireless support node over network links107. PDCP123routes the direct portion toward wireless UEs111-113, and wireless access node121wirelessly transfers the direct portion to wireless UEs111-113over wireless links101-103. Wireless support node122receives the indirect portion over network links107and wirelessly transfers the indirect portion to wireless UEs111-113over wireless links104-106.

Wireless UE111initially receives user data in an unsynchronized manner over wireless links101and104due to the significant transmission time difference between the direct delivery and the indirect delivery. When PDCP123estimates the time difference and applies the corresponding time delay, wireless UE111subsequently receives user data in a synchronized manner over wireless links101and104due to the equalized transmission time difference between the direct and the indirect delivery. Wireless UE112initially receives user data in an unsynchronized manner over wireless links102and105, but when PDCP123estimates the time difference and applies the corresponding time delay, wireless UE112receives user data in a synchronized manner over wireless links102and105. Likewise, wireless UE113initially receives user data in an unsynchronized manner over wireless links103and106, but when PDCP123estimates the time difference and applies the corresponding time delay, wireless UE113receives user data in a synchronized manner over wireless links103and106.

Wireless nodes121-122comprise Fifth Generation New Radio (5GNR) gNodeBs, Long Term Evolution (LTE) eNodeBs, Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WIFI) hotspots, Low-Power Wide Area Network (LP-WAN) access points, and/or some other wireless network apparatus. In some examples, wireless access node121comprises a 5GNR gNodeB and wireless support node122comprises an LTE eNodeB. Together, this 5GNR gNodeB and this LTE eNodeB may comprise an Evolved Universal Terrestrial Radio Access Network Dual Connectivity (EN-DC) access node. Network elements130may comprise Mobility Management Entities (MMEs), Serving Gateways (SGWs), Packet Data Network Gateways (PGWs), Home Subscriber Systems (HSS), Policy Charging Rules Functions (PCRFs), and/or some other network controllers, databases, and gateways—including Fifth Generation Core (5GC) network functions.

Wireless communication network100may comprise a Central Unit (CU) and Distributed Unit (DU). The CU might comprise the portion of wireless access node121that includes a 5GNR version of PDCP123. The CU also comprises the portion of wireless support node122that includes an LTE Radio Resource Control (RRC), LTE PDCP, LTE Radio Link Control (RLC), LTE Media Access Control (MAC), and LTE Physical Layer (PHY). The DU comprises the portion of wireless access node121that includes a 5GNR RLC, 5GNR MAC, and 5GNR PHY.

Wireless links101-106use over-the-air air electromagnetic frequencies in the low-band, mid-band, high-band, or some other portion of the electromagnetic spectrum. Wireless links101-106use protocols like 5GNR, LTE, WIFI, LP-WAN, and/or some other wireless format. Links107-109use metal, glass, air, or some other media. Links107-109use IEEE 802.3 (Ethernet), Time Division Multiplex (TDM), Data Over Cable System Interface Specification (DOCSIS), Internet Protocol (IP), Hypertext Transfer Protocol (HTTP), 5GC, 5GNR, LTE, WIFI, virtual switching, inter-processor communication, bus interfaces, and/or some other data communication protocols. Links107-109may comprise intermediate network elements like relays, routers, and controllers.

UEs111-113and wireless nodes121-122comprise antennas, amplifiers, filters, modulation, analog/digital interfaces, microprocessors, software, memories, transceivers, bus circuitry, and the like. Network elements130comprise 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 applications. The microprocessors retrieve the software from the memories and execute the software to drive the operation of wireless communication network100as described herein.

FIG. 2illustrates another exemplary operation of wireless communication network100to serve wireless UEs111-113with the synchronized data service over wireless links101-106and nodes121-122. Wireless access node121executes a PDCP (201). Wireless access node121receives user data from wireless communication network100and transfers the user data to PDCP123(202). In wireless access node121, PDCP123separates the user data into direct data and indirect data (203). PDCP123routes the direct data toward wireless UEs111-113and routes the indirect data toward wireless support node122(203). Wireless access node121wirelessly transfers the direct data to wireless UEs111-113over wireless links101-103(204). Wireless access node121transfers the indirect data to wireless support node122over network links107(204). Wireless support node122receives the indirect data over network links107(205). Wireless support node122wirelessly transfers the indirect data to wireless UEs111-113over wireless links104-106(205). Wireless UEs111-113usually receive their user data from wireless nodes121-122in an unsynchronized manner due to the significant transmission time difference between the direct delivery and the indirect delivery.

In wireless access node121, PDCP123estimates a transmission time difference between the delivery of the direct data and the indirect data (206). PDCP123may estimate the transmission time difference by: 1) multiplying direct throughput by direct buffer fill to estimate direct delivery time, 2) multiplying indirect throughput by indirect buffer fill to estimate indirect delivery time, and 3) and subtracting the shorter delivery time from the longer delivery time. Wireless access node121receives additional data from wireless communication network100and transfers the additional data to PDCP123(207). In wireless access node121, PDCP123separates the additional data into additional direct data and additional indirect data (208). PDCP123delays the direct data and/or the indirect data based on the transmission time difference to synchronize delivery of the additional data (208). Typically, the direct transmission time is shorter and is delayed by the estimated transmission time difference. PDCP123routes the direct data toward wireless UEs111-113. PDCP123routes the indirect data toward wireless support node122for delivery to wireless UEs111-113(208). Wireless access node121wirelessly transfers the direct data to wireless UEs111-113over wireless links101-103(209). Wireless access node121transfers the indirect data to wireless support node122over network links107(209). Wireless support node122receives the indirect data over network links107(210). Wireless support node122wirelessly transfers the indirect data to wireless UEs111-113over wireless links104-106(210). Wireless UEs111-113now receive their user data from wireless nodes121-122in a synchronized manner due to the insignificant transmission time difference between the direct delivery and the indirect delivery.

FIG. 3illustrates another exemplary operation of wireless communication network100to serve wireless UEs111-113with the synchronized data service over wireless links101-106and wireless nodes121-122. Wireless access node121executes PDCP123. Network elements130receive user data and transfer the user data to wireless access node121for delivery to wireless UEs111-113. Wireless access node121transfers the user data to PDCP123. PDCP123separates the user data into direct data and indirect data. PDCP123routes the direct data toward wireless UEs111-113and routes the indirect data toward wireless support node122. Wireless access node121receives the routed data from PDCP123. Wireless access node121transfers the indirect data to wireless support node122. Wireless access node121wirelessly transfers the direct data to wireless UEs111-113. Wireless support node122wirelessly transfers the indirect data to wireless UEs111-113. Wireless UEs111-113usually receive their user data from wireless nodes121-122in an unsynchronized manner due to the significant transmission time difference between direct and indirect delivery.

PDCP123estimates the transmission time difference between the delivery of the direct data and the indirect data—typically based on data throughput and buffer fill for the direct delivery versus the indirect delivery. Network elements130receive additional user data and transfer the additional user data to wireless access node121for delivery to wireless UEs111-113. Wireless access node121transfers the additional user data to PDCP123. PDCP123separates the additional user data into direct data and indirect data. PDCP123delays the direct data and/or the indirect data based on the estimated transmission time difference to synchronize delivery of the additional user data to UEs111-113over wireless nodes121-122. Typically, the direct transmission time is shorter, so the direct data is delayed. PDCP123routes the indirect data toward wireless support node122, and wireless access node121transfers the indirect data to wireless support node122. Wireless support node122wirelessly transfers the indirect data to wireless UEs111-113. PDCP123routes the direct data toward UEs111-113, and wireless access node121wirelessly transfers the direct data to wireless UEs111-113. Wireless UEs111-113receive their additional user data from wireless nodes121-122in a synchronized manner due to the insignificant transmission time difference between direct delivery and indirect delivery.

FIG. 4illustrates Fifth Generation New Radio (5GNR) Long Term Evolution (LTE) network400to serve 5GNR/LTE UE410with a synchronized data service over 5GNR/LTE links401-402. 5GNR/LTE network400is an example of wireless communication network100, although network100may differ. 5GNR/LTE network400comprises 5GNR/LTE UE410, Evolved Universal Terrestrial Radio Access Network Dual Connectivity (EN-DC) node420, and Network Function Virtualization Infrastructure (NFVI)430. EN-DC node420comprises 5GNR radio421, LTE radio422, Distributed Unit (DU)423, and Central Unit (CU)424. NFVI430comprises Mobility Management Entity (MME)431, Home Subscriber System (HSS)432, Serving Gateway (SGW)433, Packet Data Network Gateway (PGW)434, and Policy Charging Rules Function (PCRF)435.

PGW434exchanges user data for UE410with external systems over SGi links406. PGW434exchanges the user data with SGW433which exchanges the user data with EN-DC node420over backhaul links405. EN-DC node420wirelessly exchanges the user data with 5GNR/LTE UE410over LTE radio422and LTE link402.

PGW434continues to exchange user data for UE410with external systems over SGi links406. PGW434exchanges the user data with SGW433which exchanges the user data with EN-DC node420over backhaul links405. EN-DC node420wirelessly exchanges the user data with UE410over 5GNR/LTE links401-402. In particular, the 5GNR PDCP in CU424splits its downlink user data into a direct portion of 5GNR data and an indirect portion of LTE data. EN-DC node420wirelessly transfers the direct 5GNR data to 5GNR/LTE UE410over 5GNR link401. EN-DC node420wirelessly transfers the indirect LTE data to 5GNR/LTE UE410over LTE link402. UE410receives the user data in an unsynchronized manner over 5GNR link401and LTE link402due to the significant transmission time difference between the 5GNR delivery and the LTE delivery.

In CU424, the 5GNR PDCP estimates a downlink transmission time difference between the 5GNR data delivery and the LTE data delivery. The 5GNR downlink time may be estimated by multiplying the downlink throughput over 5GNR link401by the 5GNR RLC buffer fill in DU423. The LTE downlink time may be estimated by multiplying the downlink throughput over LTE link402by the LTE RLC buffer fill in CU424. The downlink transmission time difference may then be estimated by subtracting the 5GNR transmission time from the LTE transmission time. The transmission time difference may be designated in microseconds, milliseconds, or some other increment.

PGW434continues to exchange user data for UE410with external systems over SGi links406. PGW434exchanges the user data with SGW433which exchanges the user data with EN-DC node420over backhaul links405. EN-DC node420wirelessly exchanges the user data with UE110over 5GNR/LTE links401-402. In particular, the 5GNR PDCP in CU424splits the downlink user data into direct 5GNR data and indirect LTE data. The 5GNR PDCP delays the direct 5GNR data and/or the indirect LTE data based on the transmission time difference to synchronize data delivery to 5GNR/LTE UE410over 5GNR link401and LTE link402. Typically, the 5GNR transmission time is shorter, so the direct 5GNR data is delayed by the estimated transmission time difference. UE410now receives the user data in a synchronized manner over 5GNR link401and LTE link402due to the equalized transmission times for the 5GNR delivery and the LTE delivery.

FIG. 5illustrates Evolved Universal Terrestrial Radio Access Network Dual Connectivity (EN-DC) access node420to serve 5GNR/LTE UE410with the synchronized data service over the 5GNR/LTE links401-402. EN-DC access node420is an example of wireless nodes121-122, although nodes121-122may differ. EN-DC access node420comprises 5GNR radio421, LTE radio422, DU423, and CU424. Radios421-422comprise antennas, amplifiers, filters, modulation, analog-to-digital interfaces, DSP, memory, and transceivers (XCVR) that are coupled over bus circuitry. DU423and CU424comprise memory, CPU, and transceivers that are coupled over bus circuitry. The memory in CU424stores an operating system (OS), 5GNR PDCP, LTE PHY, LTE MAC, LTE RLC, LTE PDCP, and LTE RRC. The memory in DU423stores an operating system, 5GNR PHY, 5GNR MAC, and 5GNR RLC. The 5GNR RLC in DU423and the LTE RLC in CU424have RLC buffers for downlink user data. The CPUs in DU423and CU424execute the operating systems, PHYs, MACs, RLCs, PDCPs, and RRCs to exchange network signaling with UE410and MME431and to exchange user data between UE410and SGW433.

Note that a 5GNR gNodeB is comprised of 5GNR radio421, DU423, and the portion of CU424used by the 5GNR PDCP. An LTE eNodeB is comprised of LTE radio422and the portion of CU424used by the LTE RRC, PDCP, RLC, MAC, and PHY. For clarity, the 5GNR gNodeB and LTE eNodeB designations are omitted fromFIG. 5.

5GNR/LTE UE410is wirelessly coupled to the antennas in 5GNR radio421over 5GNR link401. 5GNR/LTE UE410is wirelessly coupled to the antennas in LTE radio422over LTE link402. A transceiver in 5GNR radio421is coupled to a transceiver in DU423over CPRI links403. A transceiver in LTE radio422is coupled to a transceiver in CU424over CPRI links403. Transceivers in DU423and CU424are coupled together over fronthaul links404. At least one transceiver in CU424is coupled to MME431and SGW433over backhaul links405. In CU424, the LTE RRC and the 5GNR PDCP are coupled over virtualized X2 links.

In LTE radio422, the antennas receive wireless LTE signals from 5GNR/LTE UE410that transport Uplink (UL) LTE signaling and UL LTE data. The antennas transfer corresponding electrical UL signals through duplexers to the amplifiers. The amplifiers boost the received UL signals for filters which attenuate unwanted energy. Demodulators down-convert the UL signals from their carrier frequency. The analog/digital interfaces convert the analog UL signals into digital UL signals for the DSP. The DSP recovers UL LTE symbols from the UL digital signals. The CPUs execute the network applications to process the UL LTE symbols and recover the UL LTE signaling and the UL LTE data. The LTE RRC processes the UL LTE signaling and Downlink (DL) S1-MME signaling to generate new UL S1-MME signaling and new DL LTE signaling. The LTE RRC transfers the new UL S1-MME signaling to MME431over the backhaul links. The LTE PDCP transfers the UL LTE data to LTE SGW433over backhaul links405.

In CU424, the LTE RRC receives the DL S1-MME signaling from MME431, and the LTE PDCP receives DL LTE data from SGW433. The LTE RRC, PDCP, RLC, MAC and PHY process the new DL LTE signaling and the DL LTE data to generate corresponding DL LTE symbols that carry the DL LTE signaling and DL LTE data. In LTE radio422, the DSP processes the DL LTE symbols to generate corresponding digital signals for the analog-to-digital interfaces. The analog-to-digital interfaces convert the digital DL signals into analog DL signals for modulation. Modulation up-converts the DL signals to their carrier frequency. The amplifiers boost the modulated DL signals for the filters which attenuate unwanted out-of-band energy. The filters transfer the filtered DL signals through duplexers to the antennas. The electrical DL signals drive the antennas to emit corresponding wireless LTE signals that transport the DL LTE signaling and DL LTE data to UE410.

In 5GNR radio501, the antennas receive wireless 5GNR signals from 5GNR/LTE UE410that transport Uplink (UL) 5GNR signaling and UL 5GNR data. The antennas transfer corresponding electrical UL signals through duplexers to the amplifiers. The amplifiers boost the received UL signals for filters which attenuate unwanted energy. Demodulators down-convert the UL signals from their carrier frequency. The analog/digital interfaces convert the analog UL signals into digital UL signals for the DSP. The DSP recovers UL 5GNR symbols from the UL digital signals. The CPUs execute the network applications to process the UL 5GNR symbols and recover the UL 5GNR signaling and the UL 5GNR data. The 5GNR PDCP processes the UL 5GNR signaling and DL X2 signaling from the LTE RRC to generate new UL X2 signaling and new DL 5GNR signaling. The 5GNR PDCP transfers the new UL X2 signaling to the LTE RRC in CU424. The 5GNR PDCP transfers the UL 5GNR data to SGW433over backhaul links405.

In CU424, the 5GNR PDCP receives the DL X2 signaling from the LTE RRC. The 5GNR PDCP also receives DL 5GNR data from SGW433. The 5GNR PDCP, RLC, MAC, and PHY process the new DL 5GNR signaling and the DL 5GNR data to generate corresponding DL 5GNR symbols that carry the DL 5GNR signaling and DL 5GNR data. In 5GNR radio421, the DSP processes the DL 5GNR symbols to generate corresponding digital signals for the analog-to-digital interfaces. The analog-to-digital interfaces convert the digital DL signals into analog DL signals for modulation. Modulation up-converts the DL signals to their carrier frequency. The amplifiers boost the modulated DL signals for the filters which attenuate unwanted out-of-band energy. The filters transfer the filtered DL signals through duplexers to the antennas. The electrical DL signals drive the antennas to emit corresponding wireless 5GNR signals that transport the DL 5GNR signaling and DL 5GNR data to UE410.

In operation, 5GNR/LTE UE410attaches to the LTE RRC in CU424over LTE radio422and indicates its 5GNR UE capability. The LTE RRC requests data service for UE410from MME431and indicates the 5GNR UE capability. MME431responds to the LTE RRC with APNs, QCIs, network addresses, and 5GNR instructions for UE410. The LTE RRC transfers the APNs, QCIs, network addresses, and 5GNR instructions to UE410over the LTE RLC, LTE MAC, LTE PHY, and LTE radio422. The LTE PDCP in CU424exchanges user data with SGW433. The LTE PDCP exchanges user data with UE410over the LTE RLC, LTE MAC, LTE PHY, and LTE radio422.

In response to the 5GNR instructions, 5GNR/LTE UE410measures and reports the signal strength of 5GNR link401to the LTE RRC. Since the APNs/QCIs for UE410warrant 5GNR transmission and the signal quality over 5GNR link401is adequate, the LTE RRC directs UE410to attach to 5GNR radio421over 5GNR link401. The LTE RRC signals the 5GNR attachment to MME431. MME431directs SGW433to serve UE410over another connection in backhaul links405to the 5GNR PDCP in CU424.

SGW433exchanges user data with the 5GNR PDCP in CU424. The 5GNR PDCP exchanges the user data with UE410over radios421-422. In particular, the 5GNR PDCP in CU424splits the user data evenly (50/50) into direct 5GNR data and indirect LTE data. The 5GNR PDCP in CU424transfers the 5GNR data to 5GNR/LTE UE410over the 5GNR RLC, 5GNR MAC, 5GNR PHY, and 5GNR radio421. The 5GNR PDCP in CU424transfers the LTE data to 5GNR/LTE UE410over the LTE RLC, LTE MAC, LTE PHY, and LTE radio422.

In CU424, the 5GNR PDCP estimates a downlink transmission time difference between the 5GNR data delivery and the LTE data delivery. The 5GNR downlink time may be estimated by multiplying the downlink throughput over 5GNR link401and the 5GNR RLC buffer fill in DU423. The LTE downlink time may be estimated by multiplying the downlink throughput over LTE link402and the LTE RLC buffer fill in CU424. The downlink transmission time difference may then be estimated by subtracting the 5GNR transmission time from the LTE transmission time. The transmission time difference may be designated in microseconds, milliseconds, or some other increment.

PGW434continues to exchange user data for UE410with external systems over SGi links406. PGW434exchanges the user data with SGW433which exchanges the user data with EN-DC node420over backhauls links405. EN-DC node420wirelessly exchanges the user data with UE410over CU424, DU423, radios421-422, and links401-402. In particular, the 5GNR PDCP in CU424splits its downlink user data into 5GNR data and LTE data. The 5GNR PDCP delays the 5GNR data and/or the LTE data on the transmission time difference to synchronize data delivery to 5GNR/LTE UE410over 5GNR link401and LTE link402. Typically, the 5GNR transmission time is shorter, so the 5GNR data is delayed by the estimated transmission time difference. UE410now receives the user data in a synchronized manner over 5GNR link401and LTE link402due to the equalized transmission times for the 5GNR delivery and the LTE delivery.

SGW433exchanges user data with EN-DC node420over backhaul links405. MME431receives S1-MME signaling from EN-DC node420that request data services for UE410. MME431interacts with HSS432to authenticate and authorize UE410for wireless data services that are represented by APNs—and that include 5GNR service for UE410. MME431generates 5GNR instructions for UE410responsive to the 5GNR indication in the S1-MME signaling and the authorization. MME431transfers the APNs for UE410to PGW434over SGW433. PGW434interacts with PCRF435to select QCIs and network addresses for UE410based on the APNs. PGW434transfers the APNs, QCIs, and addresses to MME431over SGW433. MME431transfers the APNs, QCIs, network addresses, and 5GNR instructions for UE410to EN-DC node420. PGW434exchanges user data for UE410with external systems over SGi links406. PGW434exchanges the user data with SGW434which exchanges the user data with the LTE PDCP in EN-DC node420(not shown onFIG. 6). MME431receive signaling from EN-DC node420that indicates UE410is ready for the 5GNR data service. MME431directs SGW433to serve UE410over the 5GNR PDCP in EN-DC node420. As PGW434continues to exchange user data for UE410with external systems over SGi links406, SGW433exchanges some of this user data with the LTE PDCP in EN-DC node420and exchanges the rest of the user data with the 5GNR PDCP in EN-DC node420.

FIG. 7illustrates 5GNR/LTE UE400that receives the synchronized data service over 5GNR/LTE links401-402and EN-DC access node420. 5GNR/LTE UE410is an example of UEs111-113, although UEs111-113may differ. UE410comprises 5GNR radio701, LTE radio702, and user circuitry703that are coupled over bus circuitry. Radios701-702comprise antennas, amplifiers, filters, modulation, analog-to-digital interfaces, DSP, and memory that are coupled over bus circuitry. User circuitry703comprises user interfaces, CPU, and memory that are coupled over bus circuitry. The antennas in radios701-702are wirelessly coupled to EN-DC node420over links401-402. The user interfaces in user circuitry703comprise graphic displays, machine controllers, sensors, cameras, transceivers, and/or some other user components. The memory in user circuitry703stores an operating system, user applications (USER), and network applications for 5GNR and LTE (PHY, MAC, RLC, PDCP, and RRC). The CPU in user circuitry703executes the operating system and the user applications to generate and consume user data. The CPU in user circuitry703executes the operating system and the network applications to wirelessly exchange corresponding signaling and data with EN-DC node420over radios701-702.

The LTE RRC in 5GNR/LTE UE410attaches to the LTE RRC in EN-DC node420over the LTE RLC, MAC, PHY, radio702, and link402. The LTE RRC in UE410indicates its 5GNR UE capability to the LTE RRC in EN-DC node420. The LTE RRC receives APNs, QCIs, network addresses, and 5GNR instructions from the LTE RRC in EN-DC node420. EN-DC node420wirelessly exchanges user data with the LTE PDCP in 5GNR/LTE UE410over the LTE RLC, MAC, PHY, radio702, and link402. In response to the 5GNR instructions, the LTE RRC directs the 5GNR PHY to measure and report the signal strength of 5GNR link401from EN-DC node420(and typically other 5GNR links). Since the APNs/QCIs for UE410warrant 5GNR transmission and the signal quality over 5GNR link401is adequate, the LTE RRC directs the 5GNR PDCP to attach to the 5GNR PDCP in EN-DC node420over 5GNR link401. The 5GNR PDCP in UE410exchanges user data with the 5GNR PDCP in EN-DC node420over 5GNR radio701, 5GNR link401, and their 5GNR RLCs, MACs, and PHYs. In particular, the 5GNR PDCP in EN-DC node420splits the user data for delivery over 5GNR link401and over LTE link402. The 5GNR PDCP in EN-DC node420delays some of the user data to synchronize delivery over 5GNR/LTE links401-402.

FIG. 8illustrates the operation of 5GNR LTE network400to serve 5GNR/LTE UE410with the synchronized data service over EN-DC access node420. The LTE RRC in 5GNR/LTE UE410attaches to the LTE RRC in EN-DC node420over their LTE PDCPs, RLCs, MACs, and PHYs. The LTE RRC in UE410indicates its 5GNR capability. The LTE RRC in EN-DC node420requests data service for UE410from MME431and indicates the 5GNR UE capability. MME431interacts with HSS432to authenticate and authorize LTE/5GNR UE410for wireless data services that are indicated by APNs. MME431generates 5GNR instructions for UE410in response to the 5GNR UE capability and the UE authorization. MME431transfers the APNs for UE410to PGW434over SGW433. PGW434interacts with PCRF435to select QCIs and network addresses for LTE/5GNR UE410based on the APNs. PGW434transfers the APNs, QCIs, and network addresses for UE410to MME431over SGW433. MME431transfers the APNs, QCIs, network address, and 5GNR instructions for UE410to the LTE RRC in EN-DC node420. The LTE RRC in EN-DC node420transfers the selected APNs, QCIs, network addresses, and 5GNR instructions to the LTE RRC in UE410over their LTE PDCPs, RLCs, MACs, and PHYs. PGW434exchanges user data for UE410with external systems. PGW434exchanges the user data with SGW433which exchanges the user data with the LTE PDCP in EN-DC node420. The LTE PDCP in EN-DC node420wirelessly exchanges the user data with the LTE PDCP in UE410over their LTE RLCs, MACs, and PHYs.

In response to the 5GNR instructions, the LTE RRC in UE410directs the 5GNR PHY in UE410to measure the 5GNR signal quality from EN-DC node420. The LTE PHY reports the 5GNR signal quality to the LTE RRC in UE410, and the LTE RRC in UE410reports the 5GNR signal quality to the LTE RRC in EN-DC node420. The LTE RRC in EN-DC node420directs the LTE RRC in UE410to attach to EN-DC node420over 5GNR. The LTE RRC in UE directs the 5GNR PDCP in UE410to attach to EN-DC node420. The 5GNR PDCP in UE410attaches to the 5GNR PDCP in EN-DC node420over their 5GNR RLCs, MACs, and PHYs. The 5GNR PDCP in EN-DC node420signals the 5GNR attachment to the LTE RRC in EN-DC node420, and the LTE RRC signals the 5GNR attachment to MME431. MME431directs SGW433to serve UE410over the 5GNR PDCP in EN-DC node420.

PGW434continues to exchange user data for UE410with external systems. PGW434exchanges the user data with SGW433which exchanges the user data with the LTE PDCP and the 5GNR PDCP in EN-DC node420. The LTE PDCP in EN-DC node420and the LTE PDCP in UE410exchange the user data over their LTE PDCPs, RLCs, MACs, and PHYs. The 5GNR PDCP in EN-DC node420and the 5GNR PDCP in UE410exchange the user data over their 5GNR PDCPs, RLCs, MACs, and PHYs.

In addition, the 5GNR PDCP in EN-DC node420splits its downlink user data into 5GNR data and LTE data. The 5GNR PDCP in EN-DC node420routes the 5GNR data to the 5GNR PDCP in UE410over their 5GNR RLCs, MACs, and PHYs. The 5GNR PDCP in EN-DC node420routes the LTE data to the LTE RLC in EN-DC420, and the LTE RLC transfers the LTE data to the LTE PDCP in UE410over the LTE RLC, MACs, and PHYs.

In EN-DC node420, the 5GNR PDCP multiplies the downlink 5GNR throughput by the downlink 5GNR RLC buffer fill to get a 5GNR delivery time. The 5GNR PDCP multiplies the downlink LTE throughput by the downlink LTE RLC buffer fill to get an LTE delivery time. The 5GNR PDCP determines the difference between the LTE delivery time and the 5GNR delivery time. When the 5GNR delivery time is shorter (typical), the 5GNR PDCP delays the downlink 5GNR data by the time difference. When the LTE delivery time is shorter (atypical), the 5GNR PDCP delays the downlink LTE data by the time difference.

PGW434continues to exchange user data for UE410with external systems. PGW434exchanges the user data with SGW433which exchanges the user data with the LTE PDCP and the 5GNR PDCP in EN-DC node420. The LTE PDCP in EN-DC node420and the LTE PDCP in UE410exchange the user data over their LTE PDCPs, RLCs, MACs, and PHYs. The 5GNR PDCP in EN-DC node420and the 5GNR PDCP in UE410exchange the user data over their 5GNR PDCPs, RLCs, MACs, and PHYs.

In addition, the 5GNR PDCP in EN-DC node420splits downlink user data into 5GNR data and LTE data. The 5GNR PDCP delays the 5GNR data and/or the LTE data by the time difference to synchronize data delivery to UE410. The 5GNR PDCP in EN-DC node420routes the 5GNR data to the 5GNR PDCP in UE410over their 5GNR RLCs, MACs, and PHYs. The 5GNR PDCP in EN-DC node420routes the LTE data to the LTE RLC in EN-DC420, and the LTE RLC transfers the LTE data to the LTE PDCP in UE410over the LTE RLC, MACs, and PHYs. UE410receives the 5GNR data and the LTE data in a synchronized manner due to the equalized delivery times.

The wireless data network circuitry described above comprises computer hardware and software that form special-purpose network circuitry to serve wireless UEs with a synchronized data service over multiple wireless links. 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 circuitry 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.