Method to enable voice services over the control plane

Abstract

A method for wireless communication by a user equipment (UE) includes receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP). The method also includes transmitting, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

Description

METHOD TO ENABLE VOICE SERVICES OVER THE CONTROL PLANECROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Greece Patent Application No. 20240100168, filed on March 8, 2024. and titled "METHOD TO ENABLE VOICE SERVICES OVER THE CONTROL PLANE,” the disclosure of which is expressly incorporated by reference in its entirety.FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to wireless communications, and more specifically to a method to enable voice services over a control plane of a wireless network.BACKGROUND

[0003] Wireless communications systems are widely deployed to provide various telecommunications services such as telephony, video, data, messaging, and broadcasts. Typical wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available system resources (e g., bandwidth, transmit power, and / or the like). Examples of such multipleaccess technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency -division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, singlecarrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE- Advanced is a set of enhancements to the universal mobile telecommunications system (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). Narrowband (NB)-Intemet of things (loT) and enhanced machine-type communications (eMTC) are a set of enhancements to LTE for machine type communications.

[0004] A wireless communications network may include a number of base stations (BSs) that can support communications for a number of user equipment (UEs). A user equipment (UE) may communicate with a base station (BS) via the downlink anduplink. The downlink (or forw ard link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail, a BS may be referred to as a Node B, an evolved Node B (eNB), a gNB, an access point (AP), a radio head, a transmit and receive point (TRP), a new radio (NR) BS, a 5G Node B, and / or the like.

[0005] The above multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. New radio (NR), which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix OFDM on the downlink (DE), using cyclic prefix OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.SUMMARY

[0006] Various aspects of the present disclosure are directed to a method for wireless communication by a UE. The method includes receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP). The method also includes transmitting, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

[0007] Other aspects of the present disclosure is directed to an apparatus including means for receiving, from a first network node, a broadcast message indicating support for voice sendees over a CP. The apparatus further includes means for transmitting, to the first netw ork node, one or more voice packets over the CP in accordance with receiving the broadcast message.

[0008] In some others aspects of the present disclosure, a non-transitory computer- readable medium with non-transitory program code recorded thereon is disclosed. The program code is executed by a processor and includes program code to receive, from afirst network node, a broadcast message indicating support for voice services over a CP. The program code further includes program code to transmit, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

[0009] Some other aspects of the present disclosure is directed to UE having one or more processors; and one or more memories coupled with the one or more processors and storing processor-executable code that, when executed by the one or more processors, is configured to cause the UE to receive, from a first network node, a broadcast message indicating support for voice services over a CP. The execution of the processor-executable code further causes the UE to transmit, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

[0010] Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and processing system as substantially described with reference to and as illustrated by the accompanying drawings and specification.

[0011] The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] So that features of the present disclosure can be understood in detail, a particular description may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawingsillustrate only certain aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.

[0013] FIGURE 1 is a block diagram conceptually illustrating an example of a wireless communications network, in accordance with various aspects of the present disclosure.

[0014] FIGURE 2 is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communications network, in accordance with various aspects of the present disclosure.

[0015] FIGURE 3 is a block diagram illustrating an example disaggregated base station architecture, in accordance with various aspects of the present disclosure.

[0016] FIGURE 4 is a timing diagram illustrating an example of signaling between a first network node and a UE to facilitate voice services over a control plane, in accordance with various aspects of the present disclosure.

[0017] FIGURE 5 is a flow diagram illustrating an example process performed, for example, by a user equipment (UE), in accordance with various aspects of the present disclosure.DETAILED DESCRIPTION

[0018] Various aspects of the disclosure are described more fully below with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings, one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth. In addition, the scope of the disclosure is intended to cover such an apparatus or method, which is practiced usingother structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth. It should be understood that any aspect of the disclosure disclosed may be embodied by one or more elements of a claim.

[0019] Several aspects of telecommunications systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and / or the like (collectively referred to as “elements"’). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0020] It should be noted that while aspects may be described using terminology commonly associated with 5G and later wireless technologies, aspects of the present disclosure can be applied in other generation-based communications systems, such as and including 3G and / or 4G technologies.

[0021] A narrowband Intemet-of-things (NB-IoT) device, such as an NB-IoT user equipment (UE), may be specified to support control plane cellular loT (CP CIoT) communication. CP CIoT is designed to transmit minimal data pay loads by forgoing application security. In such cases, data may be transmitted using a signaling radio bearer (SRB), specifically SRBlbis. SRBlbis may be reserved for control plane communications between a UE (e.g., NB-IoT UE) and a network node. The control plane communications may be used for one or more operations, such as, but not limited to, UE registration, mobility updates, and security procedures. The one or more operations may be functions of a non-access stratum (NAS) protocol.

[0022] In some cases, the control plane (e.g., CP CIoT) may transmit small data packets, such as a single 20-byte packet. In such cases, using the control plane eliminates the need to establish user plane (UP) bearers, which may be a complex and signal-intensive process. When using the control plane, data is encapsulated within a container that is then incorporated into a NAS message, for example, an evolved session management (ESM) data transport message. This encapsulation and transmission process may reduce resource use and may also reduce signaling overhead.

[0023] Due to its tow complexity and cost-effectiveness, NB-IoT has emerged as a preferred technology for non-terrestrial networks (NTNs). However, NB-IoT inherently lacks the capability to provide voice services. Thus, it may be desirable to enable voice sendees overNB-IoT within a non-terrestrial network. In some examples, voice data may be transmitted over a control plane, utilizing NAS messaging. Various aspects of the present disclosure are directed to modifying an access stratum (AS) layer to facilitate low overhead control plane data transmissions, over the air. In some examples, signaling may be specified to enable voice communications over the control plane. As an example, a UE may indicate its intent to use voice services over the control plan via a radio resource control (RRC) connection request message (e.g., Msg3). Additionally, or alternatively, a network node may broadcast a message indicating its support of voice sen ices over the control plane. In such examples, the AS layer may be modified to accommodate signaling from the UE and / or network node in order to support voice data encapsulation and delivery via the control plane.

[0024] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, the described technique of refining the AS layer may reduce the complexity and overhead associated with conventional voice data transmissions. By reducing the complexity' and overhead associated with conventional voice data transmissions, voice sendees may be implemented over NB-IoT networks, such as NB-IoT networks used by non-terrestrial networks, thereby, extending the capabilities of NB-IoT.

[0025] FIGURE 1 is a diagram illustrating a network 100 in which aspects of the present disclosure may be practiced. The network 100 may be a 5G or NR network or some other wireless network, such as an LTE network. The wireless network 100 may include a number of BSs 110 (shown as BS 110a, BS 110b. BS 110c. and BS 1 lOd) and other network entities. A BS is an entity' that communicates with user equipment (UEs) and may also be referred to as a base station, an NR BS, a Node B, a gNB, a 5GNode B, an access point, a transmit and receive point (TRP), a network node, a network entity, and / or the like. A base station can be implemented as an aggregated base station, as a disaggregated base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, etc. The base station can be implemented in an aggregated or monolithic base station architecture, or alternatively, in a disaggregated base stationarchitecture, and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near-real time (near-RT) RAN intelligent controller (RIC), or a non-real time (non-RT) RIC.

[0026] Each BS may provide communications coverage for a particular geographic area. In 3GPP, the term "‘cell” can refer to a coverage area of a BS and / or a BS subsystem serving this coverage area, depending on the context in which the term is used.

[0027] A BS may provide communications coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIGURE 1 , a BS 1 10a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB,” “base station / ’ “NR BS,” “gNB,” “AP,” “Node B.” “5GNB,” “TRP,” and “cell” may be used interchangeably.

[0028] In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and / or to one or more other BSs or network nodes (not shown) in the wireless netw ork 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and / or the like using any suitable transport network.

[0029] The wireless network 100 may also include relay stations. A relay station is an entity7that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. In theexample shown in FIGURE 1. a relay station 1 lOd may communicate with macro BS 110a and a UE 120d in order to facilitate communications between the BS 110a and UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, and / or the like.

[0030] The wireless network 100 may be a heterogeneous network that includes BSs of different types (e.g., macro BSs, pico BSs, femto BSs, relay BSs, and / or the like). These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0. 1 to 2 watts).

[0031] As an example, the BSs 110 (shown as BS 110a, BS 1 10b, BS 1 10c, and BS 1 lOd) and the core network 130 may exchange communications via backhaul links 132 (e.g., SI, etc.). Base stations 110 may communicate with one another over other backhaul links (e g., X2, etc.) either directly or indirectly (e.g., through core network 130).

[0032] The core network 130 may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may be the control node that processes the signaling between the UEs 120 and the EPC. All user IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operator's IP services. The operator's IP services may include the Internet, the Intranet, an IP multimedia subsystem (IMS), and a packet-switched (PS) streaming service.

[0033] The core network 130 may provide user authentication, access authorization, tracking, IP connectivity, and other access, routing, or mobility functions. One or more of the base stations 110 or access node controllers (ANCs) may interface with the core network 130 through backhaul links 132 (e.g., SI, S2, etc.) and may perform radio configuration and scheduling for communications with the UEs 120. In some configurations, various functions of each access network entity or base station 110 maybe distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 110).

[0034] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100. and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, and / or the like. A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors / devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jew elry' (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicular component or sensor, smart meters / sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

[0035] One or more UEs 120 may establish a protocol data unit (PDU) session for a network slice. In some cases, the UE 120 may select a netw ork slice based on an application or subscription service. By having different netw ork slices serving different applications or subscriptions, the UE 120 may improve its resource utilization in the wireless network 100, while also satisfying performance specifications of individual applications of the UE 120. In some cases, the netw ork slices used by UE 120 may be served by an AMF (not shown in FIGURE 1) associated with one or both of the base station 110 or core network 130. In addition, session management of the network slices may be performed by an access and mobility management function (AMF).

[0036] The UEs 120 may include a voice over control plane (CP) module 140. For brevity7, only one UE 120d is shown as including the voice over CP module 140. The voice over CP module 140 may perform one or more operations, such as one or more operations associated with the process 500 described with reference to FIGURE 5.

[0037] Some UEs may be considered machine-type communications (MTC) or evolved or enhanced machine-type communications (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors.location tags, and / or the like, that may communicate with a base station, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Intemet-of-Things (loT) devices, and / or may be implemented as NB-IoT (narrow band internet of things) devices. Some UEs may be considered a customer premises equipment (CPE). UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and / or the like.

[0038] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, and / or the like. A frequency may also be referred to as a carrier, a frequency channel, and / or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless netw orks of different RATs. In some cases, NR or 5G RAT netw orks may be deployed.

[0039] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another). For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and / or the like), a mesh netw ork, and / or the like. In this case, the UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere as being performed by the base station 110. For example, the base station 110 may configure a UE 120 via downlink control information (DCI), radio resource control (RRC) signaling, a media access control-control element (MAC-CE) or via system information (e.g., a system information block (SIB).

[0040] As indicated above, FIGURE 1 is provided merely as an example. Other examples may differ from what is described with regard to FIGURE 1.

[0041] FIGURE 2 shows a block diagram of a design 200 of the base station 110 and UE 120, which may be one of the base stations and one of the UEs in FIGURE 1. The base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T > 1 and R > 1.

[0042] At the base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs. Decreasing the MCS lowers throughput but increases reliability7of the transmission. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) and / or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and / or the like) and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS)) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondarysynchronization signal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and / or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for orthogonal frequency division multiplexing (OFDM) and / or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t. respectively. According to various aspects described in more detail below, the synchronization signals can be generated with location encoding to convey additional information.

[0043] At the UE 120, antennas 252a through 252r may receive the downlink signals from the base station 110 and / or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) areceived signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM and / or the like) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. A channel processor may determine reference signal received power (RSRP), received signal strength indicator (RS SI), reference signal received quality (RSRQ), channel quality indicator (CQI), and / or the like. In some aspects, one or more components of the UE 120 may be included in a housing.

[0044] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g.. for reports comprising RSRP, RSSI, RSRQ, CQI, and / or the like) from the controller / processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for discrete Fourier transform spread OFDM (DFT-s-OFDM), CP-OFDM, and / or the like), and transmitted to the base station 110. At the base station 110, the uplink signals from the UE 120 and other UEs may be received by the antennas 234, processed by the demodulators 254, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to a controller / processor 240. The base station 110 may include communications unit 244 and communicate to the core network 130 via the communications unit 244. The core network 130 may include a communications unit 294, a controller / processor 290, and a memory 292.

[0045] The controller / processor 240 of the base station 110. the controller / processor 280 of the UE 120. and / or any other component(s) of FIGURE 2 may perform one or more techniques associated with enabling voice services over a control plane as described in more detail elsewhere. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or any othercomponent(s) of FIGURE 2 may perform or direct operations of. for example, the process 500 of FIGURE 5 and / or other processes as described. Memories 242 and 282 may store data and program codes for the base station 110 and UE 120, respectively. A scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0046] In some aspects, the UE 120 and / or base station 110 may include means for receiving, means for receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP), means for transmitting, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message, means for receiving, from the first network node, a message indicating a list of neighbor cells that support the voice services over the CP, means for transmitting, to the first network node, a radio resource control (RRC) connection request message indicating the UE intends to use the voice services over the CP. and means for transmitting, to a second network node, a UE capability message indicating the UE is capable of supporting the voice services over the CP. Such means may include one or more components of the UE 120 or base station 110 described in connection with FIGURE 2.

[0047] As indicated above, FIGURE 2 is provided merely as an example. Other examples may differ from what is described with regard to FIGURE 2.

[0048] Deployment of communication systems, such as 5G new radio (NR) systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS), or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, 5GNB, an access point (AP), a transmit and receive point (TRP), or a cell, etc.) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

[0049] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregatedbase station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs)). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU also can be implemented as virtual units (e.g., a virtual central unit (VCU), a virtual distributed unit (VDU). or a virtual radio unit (VRU)).

[0050] Base station-type operations or network designs may consider aggregation characteristics of base station functionality'. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

[0051] In some cases, different types of devices supporting different types of applications and / or services may coexist in a cell. Examples of different types of devices include UE handsets, customer premises equipment (CPEs), vehicles, Internet of Things (loT) devices, and / or the like. Examples of different types of applications include ultra-reliable low -latency’ communications (URLLC) applications, massive machine-type communications (mMTC) applications, enhanced mobile broadband (eMBB) applications, vehicle-to-any'thing (V2X) applications, and / or the like. Furthermore, in some cases, a single device may support different applications or services simultaneously.

[0052] FIGURE 3 shows a diagram illustrating an example disaggregated base station 300 architecture. The disaggregated base station 300 architecture may include one or more central units (CUs) 310 that can communicate directly w ith a core network 320 via a backhaul link, or indirectly with the core network 320 through one or moredisaggregated base station units (such as a near-real time (near-RT) RAN intelligent controller (RIC) 325 via an E2 link, or anon-real time (non-RT) RIC 315 associated with a service management and orchestration (SMO) framework 305, or both). A CU 310 may communicate with one or more distributed units (DUs) 330 via respective midhaul links, such as an Fl interface. The DUs 330 may communicate with one or more radio units (RUs) 340 via respective fronthaul links. The RUs 340 may communicate with respective UEs 120 via one or more radio frequency (RF) access links. In some implementations, the UE 120 may be simultaneously served by multiple RUs 340.

[0053] Each of the units (e.g., the CUs 310, the DUs 330, the RUs 340, as well as the near-RT RICs 325, the non-RT RICs 315, and the SMO framework 305) may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units.Additionally, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver), configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

[0054] In some aspects, the CU 310 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP). service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 310. The CU 310 may be configured to handle user plane functionality (e.g., central unit - user plane (CU-UP)), control plane functionality (e.g., central unit - control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 310 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the El interface whenimplemented in an O-RAN configuration. The CU 310 can be implemented to communicate with the DU 330, as necessary, for network control and signaling.

[0055] The DU 330 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 340. In some aspects, the DU 330 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the Third Generation Partnership Project (3GPP). In some aspects, the DU 330 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 330, or with the control functions hosted by the CU 310.

[0056] Lower-layer functionality can be implemented by one or more RUs 340. In some deployments, an RU 340, controlled by a DU 330, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 340 can be implemented to handle over the air (OTA) communication with one or more UEs 120. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 340 can be controlled by the corresponding DU 330. In some scenarios, this configuration can enable the DU(s) 330 and the CU 310 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0057] The SMO framework 305 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO framework 305 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operations and maintenance interface (such as an 01 interface). For virtualized network elements, the SMO framework 305 may be configured to interact with a cloud computing platform (such as an open cloud (O-cloud) 390) toperform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 02 interface). Such virtualized network elements can include, but are not limited to, CUs 310, DUs 330, RUs 340, and near-RT RICs 325. In some implementations, the SMO framework 305 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O- eNB) 311, via an 01 interface. Additionally, in some implementations, the SMO framework 305 can communicate directly with one or more RUs 340 via an 01 interface. The SMO framework 305 also may include a non-RT RIC 315 configured to support functionality of the SMO framework 305.

[0058] The non-RT RIC 315 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updates, or policy-based guidance of applications / features in the near-RT RIC 325. The non-RT RIC 315 may be coupled to or communicate with (such as via an Al interface) the near-RT RIC 325. The near-RT RIC 325 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 310, one or more DUs 330, or both, as well as the O-eNB 311, with the near-RT RIC 325.

[0059] In some implementations, to generate AI / ML models to be deployed in the near-RT RIC 325, the non-RT RIC 315 may receive parameters or external enrichment information from external servers. Such information may be utilized by the near-RT RIC 325 and may be received at the SMO framework 305 or the non-RT RIC 315 from non-network data sources or from network functions. In some examples, the non-RT RIC 315 or the near-RT RIC 325 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 315 may monitor long-term trends and patterns for performance and employ AI / ML models to perform corrective actions through the SMO framework 305 (such as reconfiguration via 01) or via creation of RAN management policies (such as Al policies).

[0060] As discussed, a narrowband Intemet-of-things (NB-IoT) device, such as an NB-IoT UE, may support control plane cellular loT (CP CIoT) communication. CP CIoT is designed to transmit minimal data payloads by forgoing application security. Insuch cases, data may be transmited using a signaling radio bearer (SRB). specifically SRBlbis. SRBlbis may be reserved for control plane communications between a UE (e.g., NB-IoT UE) and a network node. The control plane communications may be used for one or more operations, such as, but not limited to, UE registration, mobility updates, and security procedures. The one or more operations may be functions of a non-access stratum (NAS) protocol.

[0061] In some cases, the control plane (e.g., CP CIoT) may transmit small data packets, such as a single 20-byte packet. In such cases, using the control plane eliminates the need to establish user plane (UP) bearers, which may be a complex and signal-intensive process. When using the control plane, data is encapsulated within a container that is then incorporated into a NAS message, for example, an evolved session management (ESM) data transport message. This encapsulation and transmission process may reduce resource use and may also reduce signaling overhead.

[0062] Due to its low complexity' and cost-effectiveness, NB-IoT has emerged as a preferred technology for non-terrestrial networks (NTNs). In non-terrestrial networks, communication may be facilitated via geostationary Earth orbit (GEO) satellites. In such networks, the data rate may be reduced due to complex radio conditions inherent to satellite communications and the large coverage area that each satellite beam serves. For example, each satellite beam may service a large number of UEs within an area spanning hundreds of miles in radius. In some examples, the data rates may be limited to 1.5 or 2.0 kilobits per second (kbps), which effectively translates to transmiting a packet of approximately 15-20 bytes every 80 milliseconds (ms).

[0063] In most cases, voice data may be periodically transmited, such as once every 20 ms. In conventional systems, voice data may be carried over an Internet protocol (IP) network using a protocol stack. The protocol stack may combine a real-time transport protocol (RTP) with a transmission control protocol / IP (TCP / IP). However, this protocol stack introduces overhead (e.g., IP overhead. TCP overhead, and RTP overhead). Such overhead is counterproductive with respect to the necessity for low data rates in NTN scenarios. Therefore, it may be desirable to provide an alternative to the protocol stack, such that voice services may be delivered via a non-terrestrial network without exceeding the aforementioned data constraints.

[0064] In some cases, the overhead introduced by the protocol stack may be mitigated by transmitting data over an NB-IoT network, such as an NB-IoT nonterrestrial network. However, NB-IoT networks inherently lack the capability to provide voice services. Thus, it may be desirable to enable voice sendees overNB-IoT within a non-terrestrial network.

[0065] In some cases, voice data may transmit over the control plane, specifically through NAS messages, to satisfy data constraints of some networks, such as nonterrestrial networks. As discussed, the NAS protocol operates at a higher level in the communication protocol hierarchy and is designed to convey signaling and other control-related information between a UE and a core network. By using the control plane, via NAS messages, for voice services (e.g., voice data), the voice packets may be transmitted without headers and control information associated with the IP protocol stack. As such, the overhead associated with the IP protocol stack may be eliminated or reduced. This reduction in overhead satisfies the low data rate specifications of certain communication networks, such as non-terrestrial networks.

[0066] Still, an access stratum (AS) layer may add overhead when receiving control plane (CP) data, such as non-access stratum (NAS) messages. This overhead may be protocol overhead introduced by various sub-layers. For example, an RRC layer may add two bytes, a radio link control (RLC) layer may also add two bytes, and a medium access control (MAC) layer appends an additional two bytes, which includes a length field. Cumulatively, these layers may contribute an additional six bytes of overhead to each voice packet.

[0067] In a low data rate scenario, such as two kilobits per second (kbps), this overhead may be inefficient. For example, if a voice packet is dispatched every 40 ms, resulting in a pay load of 10 bytes, the overhead from the AS layer alone is six bytes. In such cases, the overhead accounts for sixty percent of a total packet size.

[0068] In some examples, the overhead attributed to the AS layer when transmitting control plane data may be reduced. In some such examples, the overhead is reduced when transmitting voice packets (e.g., voice data) in a non-terrestrial network. By reducing the overhead, the voice packets may satisfy low data rate specifications of the non-terrestrial network.

[0069] Various aspects of the present disclosure are directed to modifying an access stratum (AS) layer to facilitate low overhead control plane data transmissions, over the air. Aspects of the present disclosure are not limited to voice services over the control plane, as other channels are contemplated, such as a new logical channel or a signal radio bearer (SRB) channel. The non-terrestrial network may support the new logical channel.

[0070] In some examples, signaling may enable voice services (e.g., voice communications) over the control plane. Voice services over the control plane may also be referred to as voice over CP, and may be used interchangeably. FIGURE 4 is a timing diagram illustrating an example 400 of signaling between a first network node 402 and a UE 120 to facilitate voice services over a control plane, in accordance with various aspects of the present disclosure. In the example of FIGURE 4, the first network node 402 is an example of a base station 110 described with reference to FIGURES 1 and 2, or a DU 330, an RU 340, or a CU 310 described with reference to FIGURE 3. Additionally, a second network node 404 may be an example of a core network 130 described with reference to FIGURE 1, or a DU 330, an RU 340, or a CU 310 described with reference to FIGURE 3.

[0071] As show n in the example of FIGURE 4, at time tl, the UE 120 may receive, from the first network node 402, a broadcast message indicating support for voice over CP. In some examples, the broadcast message may be a master information block (MIB). For NB-IoT, the MIB may include at least six spare bits. In such examples, one or more spare bits of the MIB may indicate the support of voice over CP. For example, an information element in the MIB, such as voiceOverCP-Enabled-r!9, may indicate the support of voice over CP. The information element may be a Boolean value.

[0072] By using the MIB, the UE 120 may become aware of the support for voice sendees without acquiring a system information block (SIB), such as SIB1. If the UE 120 intends to use voice over CP, the UE 120 may try to find and select other cells if the MIB does not indicate support of voice over CP. This process of indicating support via the SIB increases the delay in finding and selecting a cell that supports voice sendees over the control plane. Some systems, such as enhanced machine type communication (eMTC) systems, may not support indicating, via the MIB, the support of voice overCP. Thus, in some other examples, the broadcast message may be a SIB. The SIB information may be as follows:SystemInformationBlockTypel-NB-vl9xy ::= SEQUENCE{ voicePverCP-NTN-rl9 ENUMERATED{supported}, -- Need OR nonCriticalExtension SEQUENCE{} OPTIONAL}

[0073] In some examples, at time t2a, the UE 120 may transmit, to the second network node 404, a UE capability message, such as an RRC message, indicating that the UE 120 supports voice services over the control plane. The UE capability message may be a UE capability container message. In some examples, at time t2b, the first network node 402 may retrieve the UE capability7for supporting voice services over the control plane from the second network node 404. The UE capability may be retrieved based on the UE identifier (ID) included in a connection request message (e.g.. Msg3). The transmission of the UE capability message (e.g., at times t2a and t2b) may be optional.

[0074] Additionally, at time t3, the UE 120 may transmit, to the first network node 402, an RRC message indicating that the UE 120 intends to use voice over CP. The RRC message may be an RRC connection message, such as Msg3. In some examples, the indication at time t3 may transmit via one or more spare bits in the RRC connection request message. For example, the indication may be included in a voiceOverCP- Support-rl9 information element. In this example, the voiceOverCP-Support-rl9 information element may be enumerated as true. Additionally, a number of spare bits in the RRC connection request message may be reduced by one, for example, from seventeen to sixteen. In some other examples, the UE 120 replaces a spare value in an establishment clause information element with a new information element to indicate the support at time t3. For example, the new information element may be voice- Signaling-vl9xy. After indicating support at time t3, the UE 120 may transmit, to the first network node 402, one or more voice packets over the control plane (time t4).

[0075] In some examples, the UE 120 may prioritize its selection or reselection of a cell based on whether the cell supports voice services over the control plane. In suchexamples, the UE 120 may receive a list of neighboring cells that support voice services over the control plane (CP) (e g., voice over CP). As such, the UE 120 would know in advance which cells in the vicinity can support this feature. In conventional systems, the UE 120 may select a cell based on the received signal strength indicator (RSSI), e.g., the reference signal received power (RSRP), opting for the cell with the strongest signal. However, when considering voice over CP, the UE 120 may consider whether a cell supports voice over CP. For example, the UE 120 may determine that a first cell with the strongest RSRP does not support voice over CP, whereas a second cell with slightly weaker RSRP does support the voice over CP. In this example, the UE 120 may select the second cell based on the second cell supporting voice over CP.

[0076] Additionally, this information can extend across different radio access technologies (RATs) and be incorporated into the inter-RAT frequency list. For example, if the UE 120 is currently connected to a new radio (NR) terrestrial network cell but finds itself out of the NR terrestrial network’s coverage area, the UE 120 may use the neighbor list to make an emergency call via an NB-IoT satellite network. This capability' ensures that the UE 120 can maintain critical communication functions, such as emergency calls, even when traditional NR terrestrial network coverage is unavailable.

[0077] In some examples, the first network node 402 does not broadcast a message indicating support of voice over CP. In some such examples, the UE 120 may indicate whether it supports voice over CP via a UE capability container transmitted to the second network node 404. The UE capability container may only be reported once, unless the UE 120 switches networks (e.g., a public land mobile network (PLMN)). In such examples, after the UE 120 transmits an RRC connection request message (e.g.. Msg3) to the first network node 402. the first network node 402 may retrieve the UE capability' from the second network node 404. In this example, the RRC connection request message is not changed to indicate the support of voice services over the control plane. As discussed, the UE capability' may be retrieved based on a UE ID included in the RRC connection request message. In such examples, if the UE 120 is capable of supporting voice over CP, the first network node 402 may enable voice services over the control plane via Msg4 or another message. In some such examples, if the first network node 402 has not previously enabled the voice over CP, the first network node402 may enable such voice services via a UE-specific message, such as a downlink control information (DCI) message or a medium access channel control element (MAC- CE) message. The UE-specific message may be transmitted after the first network node 402 retrieves the UE capability from the second network node 404.

[0078] In some examples, a modified RRC connection message indicating that the UE 120 supports voice over CP may be used in conjunction with the UE capability container message. For example, the UE 120 may indicate support of voice over CP via a UE capability container transmitted to the second network node 404. In this example, the UE 120 may then indicate its intent to use voice over CP via an RRC connection request message, such as the RRC connection request message transmitted at time 13 in FIGURE 4.

[0079] As indicated above, FIGURES 3-4 are provided as examples. Other examples may differ from what is described with respect to FIGURES 3-4.

[0080] FIGURE 5 is a flow diagram illustrating an example process 500 performed, for example, by a user equipment (UE), in accordance with various aspects of the present disclosure. The example process 500 is an example of receiving signaling to enable transmission of voice packets over a control plane. The process 500 may be performed by a UE, such as a UE 120 described with reference to FIGURES 1-4. As shown in the example of FIGURE 5. the process 500 begins at block 502 by receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP). At block 504, the process 500 transmits, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

[0081] Implementation examples are described in the following numbered clauses:Clause 1. A method for wireless communication by a user equipment (UE), comprising: receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP); and transmitting, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.Clause 2. The method of Clause 1, wherein the broadcast message is a master information block (MIB) or a system information block (SIB).Clause 3. The method of any one of Clauses 1-2, further comprising receiving, from the first network node, a message indicating a list of neighbor cells that support the voice services over the CP, wherein one or more neighbor cells on the list of neighbor cells are prioritized for cell selection or reselection by the UE.Clause 4. The method of any one of Clauses 1-3, further comprising transmitting, to the first network node, a radio resource control (RRC) connection request message indicating the UE intends to use the voice services over the CP.Clause 5. The method of Clause 4, wherein one or more spare bits of the RRC connection request message indicate that the UE intends to use the voice services over the CP.Clause 6. The method of Clause 4, wherein an establishment cause information element indicates that the UE intends to use the voice services over the CP.Clause 7. The method of any one of Clauses 1-6, further comprising transmitting, to a second network node, a UE capability7message indicating the UE is capable of supporting the voice services over the CP.

[0082] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

[0083] As used, the term “component’’ is intended to be broadly construed as hardware, firmware, and / or a combination of hardware and software. As used, a processor is implemented in hardware, firmware, and / or a combination of hardware and software.

[0084] Some aspects are described in connection with thresholds. As used, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and / or the like.

[0085] It will be apparent that systems and / or methods described may be implemented in different forms of hardware, firmware, and / or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and / or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and / or methods were described without reference to specific software code — it being understood that software and hardware can be designed to implement the systems and / or methods based, at least in part, on the description.

[0086] Even though particular combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every7other claim in the claim set. A phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c- c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0087] No element, act, or instruction used should be construed as critical or essential unless explicitly described as such. Also, as used, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Furthermore, as used, the terms “set” and “group” are intended to include one or more items (e.g.. related items, unrelated items, a combination of related and unrelated items, and / or the like), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used, the terms “has,” “have.” “having,” and / or the like are intended to be open-endedterms. Further, the phrase "based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A method for wireless communication by a user equipment (UE), comprising: receiving, from a first network node, a broadcast message indicating support for voice services over a control plane (CP); and transmitting, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

2. The method of claim 1, wherein the broadcast message is a master information block (MIB) or a system information block (SIB).

3. The method of claim 1, further comprising receiving, from the first network node, a message indicating a list of neighbor cells that support the voice services over the CP. wherein one or more neighbor cells on the list of neighbor cells are prioritized for cell selection or reselection by the UE.

4. The method of claim 1, further comprising transmitting, to the first network node, a radio resource control (RRC) connection request message indicating the UE intends to use the voice services over the CP.

5. The method of claim 4. wherein one or more spare bits of the RRC connection request message indicate that the UE intends to use the voice sendees over the CP.

6. The method of claim 4, wherein an establishment cause information element indicates that the UE intends to use the voice services over the CP.

7. The method of claim 1. further comprising transmitting, to a second network node, a UE capability message indicating the UE is capable of supporting the voice services over the CP.

8. A user equipment (UE), comprising: one or more processors; and one or more memories coupled with the one or more processors and storing processor-executable code that, when executed by the one or more processors, is configured to cause the UE to: receive, from a first network node, a broadcast message indicating support for voice services over a control plane (CP); and transmit, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

9. The UE of claim 8. wherein the broadcast message is a master information block (MIB) or a system information block (SIB).

10. The UE of claim 8, wherein execution of the processor-executable code further causes the UE to receive, from the first network node, a message indicating a list of neighbor cells that support the voice services over the CP. wherein one or more neighbor cells on the list of neighbor cells are prioritized for cell selection or reselection by the UE.

11. The UE of claim 8, wherein execution of the processor-executable code further causes the UE to transmit, to the first network node, a radio resource control (RRC) connection request message indicating the UE intends to use the voice services over the CP.

12. The UE of claim 11, wherein one or more spare bits of the RRC connection request message indicate that the UE intends to use the voice services over the CP.

13. The UE of claim 11, wherein an establishment cause information element indicates that the UE intends to use the voice services over the CP.

14. The UE of claim 8, wherein execution of the processor-executable code further causes the UE to transmit, to a second network node, a UE capability message indicating the UE is capable of supporting the voice services over the CP.

15. A non-transitory computer-readable medium having program code recorded thereon for wireless communication by a user equipment (UE), the program code executed by one or more processors and comprising: program code to receive, from a first network node, a broadcast message indicating support for voice services over a control plane (CP); and program code to transmit, to the first network node, one or more voice packets over the CP in accordance with receiving the broadcast message.

16. The non-transitory computer-readable medium of claim 15, wherein the broadcast message is a master information block (MIB) or a system information block (SIB).

17. The non-transitory computer-readable medium of claim 15, wherein the program code further comprises program code to receive, from the first network node, a message indicating a list of neighbor cells that support the voice services over the CP, wherein one or more neighbor cells on the list of neighbor cells are prioritized for cell selection or reselection by the UE.

18. The non-transitory computer-readable medium of claim 15, wherein the program code further comprises program code to transmit, to the first network node, a radio resource control (RRC) connection request message indicating the UE intends to use the voice services over the CP.

19. The non-transitory computer-readable medium of claim 18, wherein one or more spare bits of the RRC connection request message indicate that the UE intends to use the voice services over the CP.

20. The non-transitory computer-readable medium of claim 18, wherein an establishment cause information element indicates that the UE intends to use the voice services over the CP.

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