Patent Publication Number: US-2021168621-A1

Title: Dynamic port allocation for ng-ran control plane interfaces

Description:
PRIORITY CLAIM 
     This application claims the benefit of priority under 35 U.S.C. 119(e) to the following United States Provisional Patent Applications: 
     U.S. Provisional Patent Application Ser. No. 62/976,765, filed Feb. 14, 2020, and entitled “DYNAMIC PORT ALLOCATION FOR NG-RAN CONTROL PLANE INTERFACES;” and 
     U.S. Provisional Patent Application Ser. No. 63/007,253, filed Apr. 8, 2020, and entitled “DYNAMIC PORT ALLOCATION FOR NG-RAN CONTROL PLANE INTERFACES.” 
     Each of the above-listed provisional patent applications is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Aspects pertain to wireless communications. Some aspects relate to wireless networks including 3GPP (Third Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, 3GPP LTE-A (LTE Advanced) networks, and fifth-generation (5G) networks including 5G new radio (NR) (or 5G-NR) networks and 5G-LTE networks such as 5G NR unlicensed spectrum (NR-U) networks. Other aspects are directed to systems and methods for dynamic port allocation for NG-RAN control plane interfaces. 
     BACKGROUND 
     Mobile communications have evolved significantly from early voice systems to today&#39;s highly sophisticated integrated communication platform. With the increase in different types of devices communicating with various network devices, usage of 3GPP LTE systems has increased. The penetration of mobile devices (user equipment or UEs) in modern society has continued to drive demand for a wide variety of networked devices in many disparate environments. Fifth-generation (5G) wireless systems are forthcoming and are expected to enable even greater speed, connectivity, and usability. Next generation 5G networks (or NR networks) are expected to increase throughput, coverage, and robustness and reduce latency and operational and capital expenditures. 5G-NR networks will continue to evolve based on 3GPP LTE-Advanced with additional potential new radio access technologies (RATs) to enrich people&#39;s lives with seamless wireless connectivity solutions delivering fast, rich content and services. As current cellular network frequency is saturated, higher frequencies, such as millimeter wave (mmWave) frequency, can be beneficial due to their high bandwidth. 
     Potential LTE operation in the unlicensed spectrum includes (and is not limited to) the LTE operation in the unlicensed spectrum via dual connectivity (DC), or DC-based LAA, and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in the unlicensed spectrum without requiring an “anchor” in the licensed spectrum, called MulteFire. MulteFire combines the performance benefits of LTE technology with the simplicity of Wi-Fi-like deployments. 
     Further enhanced operation of LTE systems in the licensed, as well as unlicensed spectrum, is expected in future releases and 5G systems. Such enhanced operations can include techniques for dynamic port allocation for NG-RAN control plane interfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       In the figures, which are not necessarily drawn to scale, like numerals may describe similar components indifferent views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various aspects discussed in the present document. 
         FIG. 1A  illustrates an architecture of a network, in accordance with some aspects. 
         FIG. 1B  and  FIG. 1C  illustrate a non-roaming 5G system architecture in accordance with some aspects. 
         FIG. 2  illustrates a block diagram of a communication device such as an evolved Node-B (eNB), a new generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), in accordance with some aspects. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate aspects to enable those skilled in the art to practice them. Other aspects may incorporate structural, logical, electrical, process, and other changes. Portions and features of some aspects may be included in or substituted for, those of other aspects. Aspects outlined in the claims encompass all available equivalents of those claims. 
       FIG. 1A  illustrates an architecture of a network in accordance with some aspects. The network  140 A is shown to include user equipment (UE)  101  and UE  102 . The UEs  101  and  102  are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but may also include any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, drones, or any other computing device including a wired and/or wireless communications interface. The UEs  101  and  102  can be collectively referred to herein as UE  101 , and UE  101  can be used to perform one or more of the techniques disclosed herein. 
     Any of the radio links described herein (e.g., as used in the network  140 A or any other illustrated network) may operate according to any exemplary radio communication technology and/or standard. 
     LTE and LTE-Advanced are standards for wireless communications of high-speed data for UE such as mobile telephones. In LTE-Advanced and various wireless systems, carrier aggregation is a technology according to which multiple carrier signals operating on different frequencies may be used to carry communications for a single UE, thus increasing the bandwidth available to a single device. In some aspects, carrier aggregation may be used where one or more component carriers operate on unlicensed frequencies. 
     Aspects described herein can be used in the context of any spectrum management scheme including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz, and further frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and further frequencies). 
     Aspects described herein can also be applied to different Single Carrier or OFDM flavors (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.) and in particular 3GPP NR (New Radio) by allocating the OFDM carrier data bit vectors to the corresponding symbol resources. 
     In some aspects, any of the UEs  101  and  102  can comprise an Internet-of-Things (IoT) UE or a Cellular IoT (CIoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. In some aspects, any of the UEs  101  and  102  can include a narrowband (NB) IoT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity-Based Service (ProSe), or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network includes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network. 
     In some aspects, any of the UEs  101  and  102  can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs. 
     The UEs  101  and  102  may be configured to connect, e.g., communicatively couple, with a radio access network (RAN)  110 . The RAN  110  may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. The UEs  101  and  102  utilize connections  103  and  104 , respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections  103  and  104  are illustrated as an air interface to enable communicative coupling and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth-generation (5G) protocol, a New Radio (NR) protocol, and the like. 
     In an aspect, the UEs  101  and  102  may further directly exchange communication data via a ProSe interface  105 . The ProSe interface  105  may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH). 
     The UE  102  is shown to be configured to access an access point (AP)  106  via connection  107 . The connection  107  can comprise a local wireless connection, such as, for example, a connection consistent with any IEEE 802.11 protocol, according to which the AP  106  can comprise a wireless fidelity (WiFi®) router. In this example, the AP  106  is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). 
     The RAN  110  can include one or more access nodes that enable connections  103  and  104 . These access nodes (ANs) can be referred to as base stations (BSs). NodeBs, evolved NodeBs (eNBs), Next Generation NodeBs (gNBs), RAN network nodes, and the like, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). In some aspects, the communication nodes  111  and  112  can be transmission/reception points (TRPs). In instances when the communication nodes  111  and  112  are NodeBs (e.g., eNBs or gNBs), one or more TRPs can function within the communication cell of the NodeBs. The RAN  110  may include one or more RAN nodes for providing macrocells, e.g., macro RAN node  111 , and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node  112 . 
     Any of the RAN nodes  111  and  112  can terminate the air interface protocol and can be the first point of contact for the UEs  101  and  102 . In some aspects, any of the RAN nodes  111  and  112  can fulfill various logical functions for the RAN  110  including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management, and data packet scheduling, and mobility management. In an example, any of the nodes  111  and/or  112  can be a new generation Node-B (gNB), an evolved node-B (eNB), or another type of RAN node. 
     The RAN  110  is shown to be communicatively coupled to a core network (CN)  120  via an S1 interface  113 . In aspects, the CN  120  may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to  FIGS. 1B-1C ). In this aspect, the S1 interface  113  is split into two parts: the S1-U interface  114 , which carries traffic data between the RAN nodes  111  and  112  and the serving gateway (S-GW)  122 , and the S1-mobility management entity (MME) interface  115 , which is a signaling interface between the RAN nodes  111  and  112  and MMEs  121 . 
     In this aspect, the CN  120  comprises the MMEs  121 , the S-GW  122 , the Packet Data Network (PDN) Gateway (P-GW)  123 , and a home subscriber server (HSS)  124 . The MMEs  121  may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs  121  may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS  124  may comprise a database for network users, including subscription-related information to support the network entities&#39; handling of communication sessions. The CN  120  may comprise one or several HSSs  124 , depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS  124  can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc. 
     The S-GW  122  may terminate the S1 interface  113  towards the RAN  110 , and routes data packets between the RAN  110  and the CN  120 . In addition, the S-GW  122  may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW  122  may include a lawful intercept, charging, and some policy enforcement. 
     The P-GW  123  may terminate an SGi interface toward a PDN. The P-GW  123  may route data packets between the EPC network  120  and external networks such as a network including the application server  184  (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface  125 . The P-GW  123  can also communicate data to other external networks  131 A, which can include the Internet, IP multimedia subsystem (IPS) network, and other networks. Generally, the application server  184  may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this aspect, the P-GW  123  is shown to be communicatively coupled to an application server  184  via an IP interface  125 . The application server  184  can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs  101  and  102  via the CN  120 . 
     The P-GW  123  may further be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF)  126  is the policy and charging control element of the CN  120 . In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE&#39;s Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with a local breakout of traffic, there may be two PCRFs associated with a UE&#39;s IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF  126  may be communicatively coupled to the application server  184  via the P-GW  123 . 
     In some aspects, the communication network  140 A can be an IoT network or a 5G network, including a 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5G NR-U) spectrum. One of the current enablers of IoT is the narrowband-IoT (NB-IoT). 
     An NG system architecture can include the RAN  110  and a 5G network core (5GC)  120 . The NG-RAN  110  can include a plurality of nodes, such as gNBs and NG-eNBs. The core network  120  (e.g., a 5G core network or 5GC) can include an access and mobility function (AMF) and/or a user plane function (UPF). The AMF and the UPF can be communicatively coupled to the gNBs and the NG-eNBs via NG interfaces. More specifically, in some aspects, the gNBs and the NG-eNBs can be connected to the AMF by NG-C interfaces, and to the UPF by NG-U interfaces. The gNBs and the NG-eNBs can be coupled to each other via Xn interfaces. 
     In some aspects, the NG system architecture can use reference points between various nodes as provided by 3GPP Technical Specification (TS) 23.501 (e.g., V15.4.0, 2018-12). In some aspects, each of the gNBs and the NG-eNBs can be implemented as a base station, a mobile edge server, a small cell, a home eNB, a RAN network node, and so forth. In some aspects, a gNB can be a master node (MN) and NG-eNB can be a secondary node (SN) in a 5G architecture. 
       FIG. 1B  illustrates a non-roaming 5G system architecture in accordance with some aspects. Referring to  FIG. 1B , there is illustrated a 5G system architecture  140 B in a reference point representation. More specifically, UE  102  can be in communication with RAN  110  as well as one or more other 5G core (5GC) network entities. The 5G system architecture  140 B includes a plurality of network functions (NFs), such as access and mobility management function (AMF)  132 , session management function (SMF)  136 , policy control function (PCF)  148 , application function (AF)  150 , user plane function (UPF)  134 , network slice selection function (NSSF)  142 , authentication server function (AUSF)  144 , and unified data management (UDM)/home subscriber server (HSS)  146 . The UPF  134  can provide a connection to a data network (DN)  152 , which can include, for example, operator services. Internet access, or third-party services. The AMF  132  can be used to manage access control and mobility and can also include network slice selection functionality. The SMF  136  can be configured to set up and manage various sessions according to network policy. The UPF  134  can be deployed in one or more configurations according to the desired service type. The PCF  148  can be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in a 4G communication system). The UDM can be configured to store subscriber profiles and data (similar to an HSS in a 4G communication system). 
     In some aspects, the 5G system architecture  140 B includes an IP multimedia subsystem (IMS)  168 B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS  168 B includes a CSCF, which can act as a proxy CSCF (P-CSCF)  162 BE, a serving CSCF (S-CSCF)  164 B, an emergency CSCF (E-CSCF) (not illustrated in  FIG. 1B ), or interrogating CSCF (I-CSCF)  166 B. The P-CSCF  162 B can be configured to be the first contact point for the UE  102  within the IM subsystem (IMS)  168 B. The S-CSCF  164 B can be configured to handle the session states in the network, and the E-CSCF can be configured to handle certain aspects of emergency sessions such as routing an emergency request to the correct emergency center or PSAP. The I-CSCF  166 B can be configured to function as the contact point within an operator&#39;s network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator&#39;s service area. In some aspects, the I-CSCF  166 B can be connected to another IP multimedia network  170 E, e.g. an IMS operated by a different network operator. 
     In some aspects, the UDM/HSS  146  can be coupled to an application server  160 E, which can include a telephony application server (TAS) or another application server (AS). The AS  160 B can be coupled to the IMS  168 B via the S-CSCF  164 B or the I-CSCF  166 B. 
     A reference point representation shows that interaction can exist between corresponding NF services. For example,  FIG. 1B  illustrates the following reference points: N 1  (between the UE  102  and the AMF  132 ), N 2  (between the RAN  110  and the AMF  132 ), N 3  (between the RAN  110  and the UPF  134 ). N 4  (between the SMF  136  and the UPF  134 ), N 5  (between the PCF  148  and the AF  150 , not shown), N 6  (between the UPF  134  and the DN  152 ), N 7  (between the SMF  136  and the PCF  148 , not shown), N 8  (between the UDM  146  and the AMF  132 , not shown), N 9  (between two UPFs  134 , not shown), N 10  (between the UDM  146  and the SMF  136 , not shown), N 11  (between the AMF  132  and the SMF  136 , not shown), N 12  (between the AUSF  144  and the AMF  132 , not shown), N 13  (between the AUSF  144  and the UDM  146 , not shown), N 14  (between two AMFs  132 , not shown), N 15  (between the PCF  148  and the AMF  132  in case of a non-roaming scenario, or between the PCF  148  and a visited network and AMF  132  in case of a roaming scenario, not shown), N 16  (between two SMFs, not shown), and N 22  (between AMF  132  and NSSF  142 , not shown). Other reference point representations not shown in  FIG. 1B  can also be used. 
       FIG. 1C  illustrates a 5G system architecture  140 C and a service-based representation. In addition to the network entities illustrated in  FIG. 1B , system architecture  140 C can also include a network exposure function (NEF)  154  and a network repository function (NRF)  156 . In some aspects, 5G system architectures can be service-based and interaction between network functions can be represented by corresponding point-to-point reference points Ni or as service-based interfaces. 
     In some aspects, as illustrated in  FIG. 1C , service-based representations can be used to represent network functions within the control plane that enable other authorized network functions to access their services. In this regard, 5G system architecture  140 C can include the following service-based interfaces: Namf  158 H (a service-based interface exhibited by the AMF  132 ), Nsmf  158 I (a service-based interface exhibited by the SMF  136 ), Nnef  158 B (a service-based interface exhibited by the NEF  154 ), Npcf  158 D (a service-based interface exhibited by the PCF  148 ), a Nudm  158 E (a service-based interface exhibited by the UDM  146 ), Naf  158 F (a service-based interface exhibited by the AF  150 ), Nnrf  158 C (a service-based interface exhibited by the NRF  156 ), Nnssf  158 A (a service-based interface exhibited by the NSSF  142 ), Nausf  158 G (a service-based interface exhibited by the AUSF  144 ). Other service-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in  FIG. 1C  can also be used. 
     In example embodiments, any of the UEs or RAN network nodes discussed in connection with  FIG. 1A - FIG. 1C  can be configured to operate using the techniques discussed herein associated with dynamic port allocation for NG-RAN control plane interfaces. 
     In some aspects, well-known port numbers for all control plane interfaces (e.g. NG, Xn, F1, etc) may be allocated by the Internet Assigned Numbers Authority (IANA). As port numbers are a scarce resource, it has become increasingly difficult to get new ports from TANA, especially based on requests to allocate a well-known port number for the W1 control interface (used in a split eNB architecture). 
     Disclosed techniques may be used for obtaining port numbers such as port numbers for NG-RAN interfaces. In the disclosed aspects, the W1 interface is used as an example, but the disclosure is not limited in this regard and the disclosed techniques can be used on all other (existing and to-be-defined) network interfaces, (e.g., Xn, F1, E1, X2, etc.). 
     In some embodiments, Stream Control Transmission Protocol (SCTP) is used as the transport protocol for W1-Control Plane (W1-C) interface. If a well-known port number (e.g., as assigned by IANA) is to be used, the ng-eNB Distributed Unit (ng-eNB-DU) would establish an SCTP connection to the well-known port number in ng-eNB-CU. After that, a W1-AP initialization procedure (i.e., W1 SETUP REQUEST) would take place. In the absence of the well-known port number, consideration may be to ensure that both ng-eNB-DU and ng-eNB-CU know on which port number the ng-eNB-DU would attempt to establish the SCTP connection. The following embodiments may be used for configuring port numbers for interfaces. 
     Embodiment 1—Using Operation, Administration, and Maintenance (OAM) Node 
     In some aspects, any port number can be used as the destination port number for the W1-C SCTP connection establishment. In some embodiments, before the W1-C connection establishment, the OAM node configures the port number to be used for W1 in both the ng-eNB-DU and the ng-eNB-CU. 
     In some aspects, both network nodes on both sides of the interface may be controlled by the same OAM node. While in the case of W1 it is likely to be the case, a single OAM node arrangement may not be assumed in all cases. For example, oftentimes NG-RAN and 5G Core network (5GC) are controlled by different OAM nodes (often from different vendors) and therefore this option would incur additional manual configuration burden. 
     Embodiment 2—Using a Domain Name System (DNS) Server 
     In some aspects, DNS discovery may be used in the core network (both EPC and 5GC) and NG-RAN. 
     This embodiment relies on procedures for DNS-based service discovery as defined in IETF RFC 6763, which specifies how DNS can be used for service discovery. 
     In some aspects, DNS service (SRV) record (as defined in IETF RFC 2782) can be used to define service for port number assignment using the following structure “&lt;Instance&gt;.&lt;Service&gt;.&lt;Domain&gt;”. For example, the W1-C “service record” can be defined as follows: “3gpp-w1.sctp.operator.com”. That is, the “domain” part is “operator.com” which can be a name of the operator deploying the NG-RAN, the “service” part can be “sctp” as SCTP is used as the transport protocol for W1, and the “instance” part can be “3gpp-w” indicating that the record carries the information (e.g., one or more port numbers) to be used for W interface establishment. 
     In some aspects, the SRV record defined for W1 would contain, among other information, the following: 
     (a) port: the port on which the W1 interface connection should be established; and 
     (b) target: the hostname of the hosting module (e.g., ng-eNB-CU). 
     An advantage of the DNS based discovery is the flexibility (once implemented and deployed, it would allow the usage of any port for W1 (or other) interfaces). Furthermore, it would be easy to maintain and update that information, e.g. when new network nodes are added. However, this embodiment is associated with the deployment of a new service such as DNS in NG-RAN. 
     Embodiment 3—Via Another 3GPP Interface 
     This embodiment relies on two assumptions, both of which would require changes in RAN3 specification: 
     (a) The port number of an interface (e.g., W1) is known at some centralized node (e.g., an AMF node). Furthermore, it may be possible to configure (e.g., in the AMF) different port numbers for different network nodes (either specific nodes or nodes from a specific vendor or of a specific version). 
     (b) The network node establishing the (e.g., W1) interface is the one connected to the centralized node. That is, the procedure of W1 interface establishment (which is currently triggered by the ng-eNB-DU) may be modified so that it is the ng-eNB-CU that would establish a new interface. 
     In some embodiments, when a new ng-eNB-DU is introduced in the network, the information about which port it uses for the W1 interface (or any other interface) establishment is configured in a centralized node, e.g. at the AMF. The configuration can be: per network node instance, per network node version, or network node vendor. 
     In some aspects, the ng-eNB-CU would inquire (e.g., periodically) the AMF about new ng-eNB-DU nodes introduced in the network and their configuration, e.g., the W1 port number. Alternatively, the AMF may “push” that information to the ng-eNB-CU (e.g., using AMF CONFIGURATION UPDATE procedure). Once the ng-eNB-CU knows the address and the port number of the newly introduced ng-eNB-DU node, it would establish the W1 connection to that address and port. 
     Embodiment 4—Using a“Local” Port Number 
     This embodiment may be considered as a “violation” of port usage principles. However, it is still a feasible solution because, unlike the Internet, NG-RAN is a closed network fully controlled by an operator. Therefore, it may be possible to assume that all the applications and services running on that network use either well-known ports, dynamic ports, or ports configured by the operator. 
     With this understanding, it may be possible to designate a certain “unused” (or rarely used in practice) port number of the W1 interface, which would then be known to both ng-eNB-CU and ng-eNB-DU as the destination port for W1 connection establishment. 
     Embodiment 5—Using a Private Port Range 
     This is a variant of Embodiment 4, with the main difference being is that a certain range of ports can be assigned by IANA for use in private intranets, in a way analogous to how 10.0.0.0/8 and 192.168.0.0/16 IP address ranges are assigned. 
     In some aspects, port numbers in the “private range” can be self-assigned to a specific application by an organization running a private intranet (in the same way as private IP addresses are assigned). Within that private intranet, the self-assigned port number can be considered unique and well-known within the limits of that private intranet, in the sense that all applications in that intranet can assume that only the self-assigned service can run on that port. 
     In some aspects, a different organization may decide to self-allocate ports in the private range differently. There is no interoperability problem because services running on different private intranets do not communicate with each other. 
       FIG. 2  illustrates a block diagram of a communication device such as an evolved Node-B (eNB), a next generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), in accordance with some aspects and to perform one or more of the techniques disclosed herein. In alternative aspects, the communication device  200  may operate as a standalone device or may be connected (e.g., networked) to other communication devices. 
     Circuitry (e.g., processing circuitry) is a collection of circuits implemented in tangible entities of the device  200  that include hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time. Circuitries include members that may, alone or in combination, perform specified operations when operating. In an example, the hardware of the circuitry may be immutably designed to carry out a specific operation (e.g., hardwired). In an example, the hardware of the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including a machine-readable medium physically modified (e.g., magnetically, electrically, moveable placement of invariant massed particles, etc.) to encode instructions of the specific operation. 
     In connecting the physical components, the underlying electrical properties of a hardware constituent are changed, for example, from an insulator to a conductor or vice versa. The instructions enable embedded hardware (e.g., the execution units or a loading mechanism) to create members of the circuitry in hardware via the variable connections to carry out portions of the specific operation when in operation. Accordingly, in an example, the machine-readable medium elements are part of the circuitry or are communicatively coupled to the other components of the circuitry when the device is operating. In an example, any of the physical components may be used in more than one member of more than one circuitry. For example, under operation, execution units may be used in a first circuit of a first circuitry at one point in time and reused by a second circuit in the first circuitry, or by a third circuit in a second circuitry at a different time. Additional examples of these components with respect to the device  200  follow. 
     In some aspects, the device  200  may operate as a standalone device or may be connected (e.g., networked) to other devices. In a networked deployment, the communication device  200  may operate in the capacity of a server communication device, a client communication device, or both in server-client network environments. In an example, the communication device  200  may act as a peer communication device in a peer-to-peer (P2P) (or other distributed) network environment. The communication device  200  may be a UE, eNB, PC, a tablet PC, an STB, a PDA, a mobile telephone, a smartphone, a web appliance, a network router, switch or bridge, or any communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by that communication device. Further, while only a single communication device is illustrated, the term “communication device” shall also be taken to include any collection of communication devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), and other computer cluster configurations. 
     Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client, or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a communication device-readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. 
     Accordingly, the term “module” is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using the software, the general-purpose hardware processor may be configured as respective different modules at different times. The software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time. 
     The communication device (e.g., UE)  200  may include a hardware processor  202  (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory  204 , a static memory  206 , and mass storage  207  (e.g., hard drive, tape drive, flash storage, or other block or storage devices), some or all of which may communicate with each other via an interlink (e.g., bus)  208 . 
     The communication device  200  may further include a display device  210 , an alphanumeric input device  212  (e.g., a keyboard), and a user interface (UI) navigation device  214  (e.g., a mouse). In an example, the display device  210 , input device  212 , and UI navigation device  214  may be a touchscreen display. The communication device  200  may additionally include a signal generation device  218  (e.g., a speaker), a network interface device  220 , and one or more sensors  221 , such as a global positioning system (GPS) sensor, compass, accelerometer, or another sensor. The communication device  200  may include an output controller  228 , such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). 
     The storage device  207  may include a communication device-readable medium  222 , on which is stored one or more sets of data structures or instructions  224  (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. In some aspects, registers of the processor  202 , the main memory  204 , the static memory  206 , and/or the mass storage  207  may be, or include (completely or at least partially), the device-readable medium  222 , on which is stored the one or more sets of data structures or instructions  224 , embodying or utilized by any one or more of the techniques or functions described herein. In an example, one or any combination of the hardware processor  202 , the main memory  204 , the static memory  206 , or the mass storage  216  may constitute the device-readable medium  222 . 
     As used herein, the term “device-readable medium” is interchangeable with “computer-readable medium” or “machine-readable medium”. While the communication device-readable medium  222  is illustrated as a single medium, the term “communication device-readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions  224 . The term “communication device-readable medium” is inclusive of the terms “machine-readable medium” or “computer-readable medium”, and may include any medium that is capable of storing, encoding, or carrying instructions (e.g., instructions  224 ) for execution by the communication device  200  and that cause the communication device  200  to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting communication device-readable medium examples may include solid-state memories and optical and magnetic media. Specific examples of communication device-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, communication device-readable media may include non-transitory communication device-readable media. In some examples, communication device-readable media may include communication device-readable media that is not a transitory propagating signal. 
     Instructions  224  may further be transmitted or received over a communications network  226  using a transmission medium via the network interface device  220  utilizing any one of a number of transfer protocols. In an example, the network interface device  220  may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network  226 . In an example, the network interface device  220  may include a plurality of antennas to wirelessly communicate using at least one of single-input-multiple-output (SIMO), MIMO, or multiple-input-single-output (MISO) techniques. In some examples, the network interface device  220  may wirelessly communicate using Multiple User MIMO techniques. 
     The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device  200 , and includes digital or analog communications signals or another intangible medium to facilitate communication of such software. In this regard, a transmission medium in the context of this disclosure is a device-readable medium. 
     Although an aspect has been described with reference to specific exemplary aspects, it will be evident that various modifications and changes may be made to these aspects without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various aspects is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.