Patent Publication Number: US-11641641-B2

Title: Primary component carrier control in a wireless access node that uses multiple radio frequency bands

Description:
RELATED CASES 
     This United States patent application is a continuation of U.S. patent application Ser. No. 16/707,558 that was filed on Dec. 9, 2019 and is entitled “PRIMARY COMPONENT CARRIER CONTROL IN A WIRELESS ACCESS NODE THAT USES MULTIPLE RADIO FREQUENCY BANDS.” U.S. patent application Ser. No. 16/707,558 is hereby incorporated by reference into this United States patent application. 
    
    
     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). 
     The wireless access nodes use radio frequency bands to exchange the wireless signals over the air with the wireless user devices. An exemplary radio frequency band might be centered at one gigahertz and be 100 megahertz wide. The radio frequency bands are often licensed from the Federal Communication Commission (FCC). The radio frequency bands are usually subdivided into frequency channels. Some wireless user devices can use multiple radio frequency bands at the same time. When using multiple frequency bands simultaneously, a bi-directional wireless link called a Primary Component Carrier (PCC) is established over one of the frequency bands. Additional Secondary Component Carriers (SCCs) are then established over the frequency bands. The wireless user device uses the PCC to signal the wireless communication network, transfer uplink data, and receive downlink data. The wireless user device uses the SCCs to receive additional downlink data. In some scenarios, an LTE eNodeB serves the PCC to the wireless user device, and multiple 5GNR gNodeBs serve the SCCs to the wireless user device. Thus, the wireless user device uses the LTE PCC to establish multiple 5GNR downlink SCCs. For the PCC, the LTE eNodeB typically selects the radio frequency that has the strongest signal at the wireless user device. 
     Unfortunately, the wireless access nodes do not efficiently serve the wireless UEs over the PCCs and the SCCs. Moreover, the wireless access nodes do not effectively select radio frequencies for the PCCs. 
     Technical Overview 
     A wireless access node serves a wireless User Equipment (UE) over radio frequency bands that comprise layers. The layers comprise parallel signals that share individual resource blocks in the radio frequency bands. In the wireless access node, radio circuitry wirelessly receives information from the wireless UE that indicates received signal strengths for the radio frequency bands. In the wireless access node, processing circuitry determines layer amounts for the radio frequency bands. The processing circuitry selects one of the radio frequency bands that has an adequate one of the received signal strengths and a higher one of the layer amounts. The radio circuitry wirelessly exchanges user data with the wireless UE over the selected one of the radio frequency bands to serve the wireless UE. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a wireless communication system comprising a wireless access node to serve wireless UEs over Primary Component Carriers (PCCs) and Secondary Component Carriers (SCCs). 
         FIG.  2    illustrates the operation of the wireless access node to serve the wireless UEs over the PCCs and SCCs. 
         FIG.  3    illustrates Multiple Input Multiple Output (MIMO) layers for the frequency band in the sector of the wireless communication system. 
         FIG.  4    illustrates UE centrality angles for the frequency band in the sector of the wireless communication system. 
         FIG.  5    illustrates available sector proportions for the frequency band in the sector of the wireless communication system. 
         FIG.  6    illustrates an electrical down-tilt angle for a frequency band in a sector of the wireless communication system. 
         FIG.  7    illustrates a wireless communication system comprising an Evolved Universal Terrestrial Radio Access New Radio Dual Connectivity (EN-DC) access node to serve wireless UEs over PCCs and SCCs. 
         FIG.  8    illustrates the EN-DC access node to serve the wireless UEs over PCCs and SCCs. 
         FIG.  9    illustrates the operation of the EN-DC access node to serve the wireless UEs over the PCCs and SCCs. 
         FIG.  10    illustrates the wireless UE that is served by the EN-DC access node over the PCCs and SCCs. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    illustrates wireless communication system  100  comprising wireless access node  110  to serve wireless User Equipment (UEs)  101 - 103  over Primary Component Carriers (PCCs) and Secondary Component Carriers (SCCs). Wireless access node  110  comprises radio circuitry  111  and processing circuitry  112 . UEs  101 - 103  might be phones, computers, robots, vehicles, or some other data appliances with wireless communication circuitry. Radio circuitry  111  is wirelessly linked to UEs  101 - 103  over the PCCs and SCCs. Radio circuitry  111  and processing circuitry  112  are coupled over data links. Processing circuitry  112  is linked to other wireless access nodes and network elements over backhaul links. 
     The PCCs transfer uplink and downlink data between wireless UEs  101 - 103  and wireless access node  110 . The SCCs transfer downlink data from wireless access node  110  to wireless UEs  101 - 103 . The PCCs and SCCs use Fifth Generation New Radio (5GNR), Long Term Evolution (LTE), Low-Power Wide Area Network (LP-WAN), or some other wireless communication protocol. The PCCs and SCCs use frequencies in the low-band, mid-band, high-band, or some other part of the electromagnetic spectrum. The PCCs and SCCs use radio frequency bands that may comprise radio frequency channels in licensed Federal Communication Commission (FCC) spectrum. The backhaul links use Institute of Electrical and Electronic Engineers (IEEE) 802.3 (Ethernet), Time Division Multiplex (TDM), Data Over Cable System Interface Specification (DOCSIS), Internet Protocol (IP), 5GNR, IEEE 802.11 (WIFI), LTE, or some other data communication protocol. 
     In wireless access node  110 , radio circuitry  111  comprises antennas, filters, amplifiers, analog-to-digital interfaces, microprocessors, memory, software, transceivers, bus circuitry, and the like. Processing circuitry  112  comprises microprocessors, memory, software, transceivers, and bus circuitry, and the like. The microprocessors comprise Digital Signal Processors (DSP), Central Processing Units (CPU), Central Processing Units (CPUs), Graphical Processing Units (GPUs), Application-Specific Integrated Circuits (ASICs), 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 and network applications. In some examples, processing circuitry  112  comprises a Radio Resource Control (RRC) in a Long Term Evolution (LTE) evolved NodeB. In some examples, wireless access node  110  comprises an Evolved Universal Terrestrial Radio Access New Radio Dual Connectivity (EN-DC) access node. 
     In operation, UE  101  detects various radio frequency bands and their received signal strengths. Each frequency band serves its own sector, and UE  101  is located in multiple overlapping sectors. Radio circuitry  111  wirelessly receives a report from wireless UE  101  indicating the detected radio frequency bands and their received signal strengths. Radio circuitry  111  transfers the report to processing circuitry  112 . Processing circuitry  112  processes the report to identify the radio frequency bands that have adequate received signal strength. For example, processing circuitry  112  may compare the received signal strengths to a signal strength threshold to determine “adequate” signal strength. 
     Processing circuitry  112  determines Multiple Input Multiple Output (MIMO) layers for the radio frequency bands. MIMO layers represent parallel radio signals that use the same time and frequency resources but that use beamforming to isolate the different signals. The MIMO layers for a radio frequency band indicate the maximum number of different isolated signals that are supported by the frequency band for all UEs in the sector. Processing circuitry  112  selects one of the identified radio frequency bands that has adequate received signal strength and that also has a larger amount of MIMO layers. In this context, a “larger” amount of MIMO layers is an amount that is more than the average of the MIMO layers for all of the frequency bands. 
     Radio circuitry  111  wirelessly exchanges user data and network signaling with wireless UE  101  over the selected frequency band to serve the PCC to UE  101 . Radio circuitry  111  wirelessly transfers additional user data to UE  101  over some of the radio frequency bands to serve the SCCs to UE  101 . Radio circuitry  111  and processing circuitry  112  exchange the user data, and processing circuitry  112  exchanges the user data with other wireless access nodes and/or network elements. 
     In some examples, processing circuitry  112  also determines UE centrality angles for the radio frequency bands. A UE centrality angle indicates the angle between the mid-sector azimuth and the UE azimuth. The centrality angle indicates UE proximity to the middle azimuth of the sector. Processing circuitry  112  selects the identified radio frequency bands having a larger amount of MIMO layers and a smaller UE centrality angle. In this context, a “smaller” UE centrality angle is an angle that is less than the average of the UE centrality angles for all of the frequency bands. 
     In some examples, processing circuitry  112  also determines available sector proportions for the radio frequency bands. An available sector proportion indicates the percentage of the sector between UE  101  and the sector edge. The available sector proportion indicates UE proximity to the front of the sector irrespective of sector size. Processing circuitry  112  selects the identified radio frequency bands having a larger amount of MIMO layers, a smaller UE centrality angle, and a larger available sector proportion. In this context, a “larger” available sector proportion is a proportion that is more than the average of the available sector proportion for all of the frequency bands. 
     In some examples, processing circuitry  112  determines electrical down-tilt angles for the individual radio frequency bands. An electrical down-tilt angle is the result of beamforming by radio circuitry  111  to direct (tilt) radio transmissions down toward the ground. Increasing the electrical down-tilt shrinks the radio coverage of a sector and decreasing the electrical down-tilt increases the radio coverage of the sector. The electrical down-tilt angles may comprise Massive-MIMO (M-MIMO) beamforming angles. Processing circuitry  112  selects one of the identified radio frequency bands that has adequate received signal strength and that also has a larger amount of MIMO layers, a smaller UE centrality angle, a larger available sector proportion, and a smaller one of the electrical down-tilt angles. In this context, a “smaller” electrical down-tilt angle is an angle that is less than the average of the down-tilt angles for all of the frequency bands. 
     In some examples, processing circuitry  112  scores the received signal strengths, the MIMO layers, the UE centrality angles, the available sector proportions and/or the electrical down-tilt angles. Processing circuitry  112  aggregates the scores for an individual radio frequency band into a common score for that frequency band. Processing circuitry  112  selects the identified radio frequency band that has the best common score. For a given radio frequency band, the received signal strength, amount of MIMO layers, UE centrality angle, available sector proportion, and electrical down-tilt angle may each be normalized with a scaling factor. The normalized values are then summed to obtain the score for the radio frequency band. 
     Wireless access node  110  selects the radio frequency band for the PCC for UE  101  based on the received signal strengths and one or more of the amounts of MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles for UE  101 . Wireless access node  110  serves UEs  102 - 103  in a similar manner. Thus, wireless access node  110  selects the radio frequency band for the PCC for UE  102  based on received signal strengths and one or more of the amounts of MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles for UE  102 . Wireless access node  110  selects the radio frequency band for the PCC for UE  103  based on received signal strengths and one or more of the amounts of MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles for UE  103 . 
     Advantageously, wireless access node  110  effectively serves wireless UEs  101 - 103  over the PCCs and SCCs. Moreover, wireless access node  110  effectively selects the radio frequency bands for the PCCs. 
       FIG.  2    illustrates the operation of wireless access node  110  to serve wireless UE  101  over the PCC and SCCs. UE  101  detects radio frequency bands and their received signal strengths ( 201 ). Each of the radio frequency bands serves its own sector, and UE  101  is located in multiple overlapping sectors. Radio circuitry  111  wirelessly receives a report from wireless UE  101  indicating the radio frequency bands and their received signal strengths ( 202 ). Radio circuitry  111  transfers the report to processing circuitry  112 . 
     Processing circuitry  112  processes the report to identify the radio frequency bands that have adequate received signal strength ( 203 ). Processing circuitry  112  determines Multiple Input Multiple Output (MIMO) layers for the individual radio frequency bands. In a given sector, radio circuitry  111  can transmit different signals over multiple antennas to the UEs in the sector (including UEs  101 - 103 ) using the same time and frequency. The UEs use beamforming techniques to isolate the different signals that share the same time and frequency. The amount of MIMO layers for a radio frequency band in a sector is the number of different signals (for all UEs) that can share the same time and frequency and still be isolated. Processing circuitry  112  selects the identified radio frequency band that has both adequate received signal strength and a larger or above average amount of MIMO layers ( 204 ). 
     Processing circuitry  112  exchanges user data with other wireless access nodes and network elements. Processing circuitry  112  and radio circuitry  111  exchange the user data. Radio circuitry  111  wirelessly exchanges the user data with wireless UE  101  over the selected frequency band to serve the PCC to UE  101 . Radio circuitry  111  wirelessly transfers user data to UE  101  over some of the radio frequency bands to serve the SCCs to UE  101 . 
       FIG.  3    illustrates Multiple Input Multiple Output (MIMO) layers for a frequency band in a sector of wireless communication system  100 . Radio circuitry  111  uses the radio frequency band to serve the sector. The MIMO layers for UE  101  comprise the number of isolated radio signals between UE  101  and radio circuitry  111  that use the same time and frequency—like the same resource block. The MIMO layers for UEs  102 - 103  comprise the number of isolated radio signals between UEs  102 - 103  and radio circuitry  111  that use the same time and frequency. The MIMO layers are formed by using multiple antennas and beamforming to isolate the different radio signals based on their different antenna signatures. For the specific radio frequency band and sector, the amount of MIMO layers comprises the total number of MIMO layers that are available for all UEs in the sector. When the signal strength for the specific radio frequency band is adequate for UE  101  and when the amount of MIMO layers for the radio frequency band is above-average, wireless access node  110  may select the specific radio frequency band for the PCC for UE  101 . UEs  102 - 103  could be served in a similar manner. 
       FIG.  4    illustrates a UE centrality angle for a radio frequency band in a sector of wireless communication system  100 . Radio circuitry  111  uses the radio frequency band to serve the sector. The sector has a “pizza slice” shape, but other sector configurations could be used. For the specific radio frequency band and sector, the centrality angle is between a mid-sector azimuth and a UE azimuth. The centrality angle is formed by the UE location in the sector as viewed from above. When the signal strength for the specific radio frequency band is adequate for UE  101  and when the centrality angle for the radio frequency band is below-average, wireless access node  110  may select the specific radio frequency band for the PCC for UE  101 . UEs  102 - 103  could be served in a similar manner. 
       FIG.  5    illustrates available sector proportions for the radio frequency band in the sector of wireless communication system  100 . Radio circuitry  111  uses the radio frequency band to serve the sector. The sector has the pizza slice shape, but other sector configurations could be used. For the specific radio frequency band and sector, the available sector portion for UE  101  is a ratio of a distance and a length. The distance is between UE  101  and the sector edge, and the length is the total distance of the sector. The available sector portion is formed by the UE location in the sector as viewed from above. The available sector portion shrinks as UE  101  approaches the far edge of the sector. When the signal strength for the specific radio frequency band is adequate for UE  101  and when the available sector portion for the radio frequency band is above-average, wireless access node  110  may select the specific radio frequency band for the PCC for UE  101 . UEs  102 - 103  could be served in a similar manner. 
       FIG.  6    illustrates an electrical down-tilt angle for the radio frequency band in the sector of wireless communication system  100 . For illustrative purposes, a portion of radio circuitry  111  is shown mounted on a tower but other mounting locations could be used. Other portions of radio circuitry  111  are located elsewhere and are not shown on  FIG.  3   . The portion of radio circuitry  111  that is shown on  FIG.  3    uses a specific radio frequency band to serve its sector. For the specific radio frequency band and sector, the electrical down-tilt angle is between a ground parallel and a null ceiling. The null ceiling is formed by beamforming transmit signals to null the signal energy above the ceiling. When the signal strength for the specific radio frequency band is adequate for UE  101  and when the electrical down-tilt for the radio frequency band is below-average, wireless access node  110  selects the specific radio frequency band for the PCC for UE  101 . UEs  102 - 103  could be served in a similar manner. 
       FIG.  7    illustrates wireless communication system  700  comprising an Evolved Universal Terrestrial Radio Access New Radio Dual Connectivity (EN-DC) access node  710  to serve wireless UE  701  over a Primary Component Carrier (PCC) and Secondary Component Carriers (SCCs). Wireless communication system  700  is an example of communication system  100 , although system  100  may differ. EN-DC access node  710  comprises Distributed Units (DUs)  711 - 714  and Centralized Unit (CU)  715 . DU  711  uses a first radio frequency band (F1) to serve a sector “A”. DU  712  uses a second radio frequency band (F2) to serve a sector “B”. DU  713  uses a third radio frequency band (F3) to serve a sector “C”. DU  714  uses a fourth radio frequency band (F4) to serve a sector “D”. Sectors A-D partially overlap, and UE  701  is present in the overlapping portions sectors A-D. 
     UE  701  detects F1-F4 and their received signal strengths. One of DUs  711 - 714  wirelessly receives a report from wireless UE  701  indicating F1-F4 and received signal strengths. The DU transfers the report to CU  715 . CU  715  processes the report to identify which of F1-F4 have received signal strength above a threshold. For example, CU  715  may determine that F4 does not have adequate received signal strength at UE  701 . 
     CU  715  may determine MIMO layers for F1-F4 and sectors A-D. CU  715  may then select one of F1-F4 that has adequate received signal strength and that also has a larger or above-average amount of MIMO layers. For example, F1-F3 may have adequate received signal strength, and CU  715  may select F3 over F1-F2 because F3 has the highest amount of MIMO layers. 
     CU  715  may determine UE centrality angles for F1-F4 and sectors A-D. CU  715  may then select one of F1-F4 that has adequate received signal strength and that also has a smaller or below-average UE centrality angle. For example, F1-F3 may have adequate received signal strength, and CU  715  may select F3 over F1-F2 because F3 has the lowest UE centrality angle. 
     CU  715  may determine available sector proportions for F1-F4 and sectors A-D. CU  715  may then select one of F1-F4 that has adequate received signal strength and that also has a larger or above-average available sector proportion. For example, F1-F3 may have adequate received signal strength, and CU  715  may select F3 over F1-F2 because F3 has the largest available sector proportion for UE  701 . 
     CU  715  may determine electrical down-tilt angles for F1-F4 and sectors A-D. CU  715  may then select one of F1-F4 that has adequate received signal strength and that also has a smaller or below-average electrical down-tilt angle. For example, F1-F3 may have adequate received signal strength, and CU  715  may select F3 over F1-F2 because F3 has the lowest electrical down-tilt angle. 
     When DU  711 , F1, and sector A are selected for UE  701 , DU  711  wirelessly exchanges user data and network signaling with UE  701  over F1 to serve the PCC. When DU  712 , F2, and sector B are selected for UE  701 , DU  712  wirelessly exchanges user data and network signaling with UE  701  over F2 to serve the PCC. When DU  713 , F3, and sector C are selected for UE  701 , DU  713  wirelessly exchanges user data and network signaling with UE  701  over F3 to serve the PCC. When DU  714 , F4, and sector D are selected for UE  701 , DU  714  wirelessly exchanges user data and network signaling with UE  701  over F4 to serve the PCC. DUs  711 - 714  wirelessly transfer additional user data to UE  701  over F1-F4 to serve SCCs. DUs  711 - 714  and CU  715  exchange the user data. CU  715  exchanges the user data with other CUs and/or network elements. 
     CU  715  may process a combination of the above factors (MIMO layer, UE centrality angle, available sector proportion, and electrical down-tilt angle) to select one of F1-F4 for the PCC for UE  701 . CU  715  may score F1-F4 by normalizing and summing the factors to select the one of F1-F4 that has adequate received signal strength and the best score. CU  715  may score F1-F4 by normalizing and summing received signal strength along with at least some of the other factors to select one of F1-F4 that has and the best score. 
       FIG.  8    illustrates EN-DC access node  710  to serve wireless UE  701  over the PCCs and the SCCs. EN-DC access node  710  is an example of wireless access node  110 , although access node  110  may differ. EN-DC access node  710  comprises Distributed Units (DUs)  711 - 714  and Centralized Unit (CU)  715 . DU  711  comprises radio circuitry  721 , memory  722 , Central Processing Units (CPU)  723 , and DU XCVR  724  that are coupled over bus circuitry. Radio circuitry  721  comprises antennas, amplifiers (AMPS), filters, modulation, analog-to-digital interfaces, Digital Signal Processors (DSP), and memory that are coupled over bus circuitry. DUs  712 - 714  are similar to DU  711  but use different frequency bands. CU circuitry  715  comprises CU XCVR  725 , memory  726 , CPU  727 , and network XCVR  728  that are coupled over bus circuitry. 
     UE  701  is wirelessly coupled to the antennas in DUs  711 - 714 . DU XCVR  724  is coupled to CU XCVR  725  over fronthaul links. Network XCVR  728  is coupled to other CUs and network elements over backhaul network links. In DU  711 , memory  722  stores operating system (OS), Physical Layer (PHY), Media Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP). In CU  715 , memory  726  stores an operating system, virtual layer, PHY, MAC, RLC, PDCP, Radio Resource Control (RRC), and Service Data Adaptation Protocol (SDAP). The virtual layer comprises hypervisor modules, virtual switches, virtual CPUs, and/or the like. CPU  727  in CU  715  executes some of the network applications (PHY, MAC, RLC, PDCP, RRC, SDAP) to drive the exchange of user data and network signaling between external systems and DUs  711 - 714 . The CPUs in DUs  711 - 714  execute some or all of the network applications (PHY, MAC, RLC, PDCP) to drive the transfer of user data and network signaling between CU  715  and UE  701 . The functionality split of the network applications (PHY, MAC, RLC, PDCP) between DUs  711 - 714  and CU  715  may vary. 
     UE  701  and the RRC in CU  715  exchange Non-Access Stratum (NAS) signaling and RRC signaling over one of DUs  711 - 714 . The RRC in CU  715  exchanges S1-MME signaling and the NAS signaling with a Mobility Management Entity (MME) over network transceiver  728 . The RRC in CU  715  processes the uplink RRC signaling and the downlink S1-MME signaling to generate new downlink RRC signaling and new uplink S1-MME signaling. 
     To establish a PCC and at least one SCC, the RRC in CU  715  processes the UE measurement report to identify F1-F4 and their Received Signal Strengths Indicators (RSSIs). The RRC selects the individual frequency bands F1-F4 that have RSSIs above a PCC strength threshold. The RRC also determines factors like MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles for the frequency bands F1-F4 that have adequate signal strength. The RRC applies normalizing factors to the factors (MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles) so each of the normalized factors has a value between 0-25 based on quality. The RRC sums the normalized factors into scores for each of F1-F4 that are between 0-100. The RRC selects the frequency band that has the best score for the PCC for UE  701 . 
     The RRC in CU  715  and the DU that uses the selected frequency band exchange signaling to establish the PCC. The RRC in CU  715  and DUs  711 - 714  exchange additional signaling to establish the SCCs. For example, the RRC in CU  715  may select F1 for the PCC and exchange RRC signaling with a PDCP in DU  711  to establish a Long Term Evolution eNodeB that serves UE  701  with uplink/downlink data. The RRC in CU  715  may also select F2-F4 for the SCCs and exchange RRC signaling with the PDCPs in DUs  712 - 714  to establish Fifth Generation New Radio (SGNR) gNodeBs that serve UE  701  with downlink data. The PDCP in DU  711  then exchanges S1-U data with one or more Serving Gateways (S-GWs) over DU transceiver  724  and possibly CU  715 . The PDCPs in DUs  712 - 714  receive S1-U data from one or more S-GWs. The PDCPs interwork between the S1-U data and RRC data. DU  711  wirelessly exchanges RRC data with UE  701 . DUs  712 - 714  wirelessly transfer user data to UE  701 . 
     In radio circuitry  721  of DU  711 , the antennas receive wireless LTE signals from UE  701  that transport the Uplink (UL) RRC signaling and 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. In modulation, demodulators down-convert the UL signals from their carrier frequency (F1). 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. In DU  711  and CU  715 , CPUs  723 / 726  execute the network applications to process the UL LTE symbols and recover the UL RRC signaling and data. In DU  711  and/or CU  715 , CPUs  723 / 726  execute the network applications to generate new UL S1-MME signaling and UL S1-U data. In CU  715 , network XCVR  728  transfers the new UL MME signaling to MMEs and the new UL 51-U data to the SGWs. 
     In CU  715 , network XCVR  728  receives Downlink (DL) S1-MME signaling from the MMEs and DL S1-U data from the SGWs. In DU  711  and CU  715 , CPUs  723 / 726  execute the network applications to generate corresponding DL RRC signaling and data. In DU  711  and CU  715 , CPUs  723 / 726  execute the network applications to process the DL RRC signaling and data to generate DL LTE symbols that carry the DL RRC signaling and data. In DU  711 , 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 (F1). 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 RRC signaling and data to UE  701  over F1. 
     DUs  712 - 714  receive DL S1-U data from the SGWs. DUs  712 - 714  generate corresponding DL RRC data. DU  711 - 714  process the DL RRC data to generate DL 5GNR symbols that carry the DL RRC data. In the DUs, the DSPs process 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 frequencies (F2-F4). 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 RRC data to UE  701  over F2-F4. 
     RRC functions comprise authentication, security, handover control, status reporting, Quality-of-Service (QoS), network broadcasts and pages, and network selection. SDAP functions comprise QoS marking and flow control. PDCP functions comprise LTE/5GNR allocations, security ciphering, header compression and decompression, sequence numbering and re-sequencing, de-duplication. 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 (HARM), user identification, random access, user scheduling, and QoS. PHY functions comprise packet formation/deformation, windowing/de-windowing, guard-insertion/guard-deletion, parsing/de-parsing, control insertion/removal, interleaving/de-interleaving, Forward Error Correction (FEC) encoding/decoding, rate matching/de-matching, scrambling/descrambling, modulation mapping/de-mapping, channel estimation/equalization, Fast Fourier Transforms (FFTs)/Inverse FFTs (IFFTs), channel coding/decoding, layer mapping/de-mapping, precoding, Discrete Fourier Transforms (DFTs)/Inverse DFTs (IDFTs), and Resource Element (RE) mapping/de-mapping. 
       FIG.  9    illustrates the operation of EN-DC access node  710  to serve wireless UE  710  over a PCC and SCCs. In UE  701 , the PHY scans for F1-F4 and reports the RSSIs to the RRC. The RRC in UE  701  transfers a measurement report indicating F1-F4 and the RSSIs to the RRC in the CU  715  (and the LTE eNodeB) over their respective PDCPs, RLCs, MACs, and PHYs. The RRC in CU  715  processes the measurement report to identify the individual frequency bands F1-F4 that have RSSIs above a threshold. The RRC determines factors like MIMO layers, UE centrality angles, available sector proportions, and electrical down-tilt angles for the individual frequency bands F1-F4 that have adequate signal strength. The RRC normalizes and sums the metrics into individual scores for F1-F4. The RRC selects one of F1-F4 that has the best score for the PCC for UE  701 . The RRC also selects ones of F1-F4 for the SCCs for UE  701 . 
     In this example, the RRC in CU  715  selects F1 for the PCC and selects F2-F4 for the SCCs. In response to the selections, the RRC in the eNodeB in CU  715  exchanges RRC signaling with the PDCP in DU  711  to extend the LTE eNodeB and serve UE  701  with UL/DL signaling and UL/DL data over their respective RLCs, MACs, and PHYs for the F1 PCC. The RRC in CU  715  also exchanges RRC signaling with the PDCPs in DUs  712 - 714  to extend the SGNR gNodeBs and serve UE  701  with DL data for the F2-F4 SCCs. The PDCP in the eNodeB in DU  711  then exchanges S1-U data with the S-GWs. The PDCPs in the gNodeBs in DUs  712 - 714  receive S1-U data from the S-GWs. The PDCPs interwork between the S1-U data and RRC data. The PDCPs in DUs  712 - 714  transfer the RRC data to the PDCP in UE  701  over their respective RLCs, MACs, and PHYs for the F2-F4 SCCs. In UE  701 , the PDCP exchanges the RRC data with the RRC which exchanges the corresponding user data with the user applications. 
       FIG.  10    illustrates wireless UE  701  that is served by EN-DC access node  710  over the PCC and SCCs. UE  701  is an example of UEs  101 - 103 , although UEs  101 - 103  may differ. UE  701  comprises radio circuitry  1031 , user interfaces  1032 , CPU  1033 , and memory  1034  which are interconnected over bus circuitry. Radio circuitry  1031  comprises antennas, amplifiers, filters, modulation, analog-to-digital interfaces, DSP, and memory that are coupled over bus circuitry. The antennas in UE  701  are coupled to EN-DC access node  710  over a PCC and SCCs that use F1-F4. User interfaces  1032  comprise graphic displays, machine controllers, sensors, cameras, transceivers, and/or some other user components. Memory  1034  stores an operating system, user applications, and network applications. The network applications comprise PHY, MAC, RLC, PDCP, and RRC. CPU  1033  executes the operating system, user applications, and network applications to exchange RRC signaling and data with EN-DC access node  710  over radio circuitry  1031 . 
     The wireless data network circuitry described above comprises computer hardware and software that form special-purpose network circuitry to serve wireless UEs with PCCs and SCCs. 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. 
     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 serve wireless UEs over PCCs and SCCs. 
     The above description and associated figures teach the best mode of the invention. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Those skilled in the art will appreciate that the features described above can be combined in various ways to form multiple variations of the invention. Thus, the invention is not limited to the specific embodiments described above, but only by the following claims and their equivalents.