Maintaining a PDU session at an inter-system change between 4g and 5g mobile networks

Abstract

An apparatus of a user equipment (UE) configured to: transmit a PDU session establishment request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a UE Session management capability information element and receive a PDU session establishment accept request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a Session management network feature support information element.

Description

MAINTAINING A PDU SESSION AT AN INTER-SYSTEM CHANGE BETWEEN 4G AND 5G MOBILE NETWORKSFIELD

[0001] Embodiments of the invention relate to wireless communications, including apparatuses, systems, and methods for maintaining a PDU session at an inter-system change between 4G and 5G mobile networks.DESCRIPTION OF THE RELATED ART

[0002] Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS) and are capable of operating sophisticated applications that utilize these functionalities.

[0003] Long Term Evolution (LTE) has been the technology of choice for the majority of wireless network operators worldwide, providing mobile broadband data and high-speed Internet access to their subscriber base. LTE was first proposed in 2004 and was first standardized in 2008. Since then, as usage of wireless communication systems has expanded exponentially, demand has risen for wireless network operators to support a higher capacity for a higher density of mobile broadband users. In 2015, a study of a new radio access technology began and, in 2017, a first release of Fifth Generation New Radio (5G NR) was standardized.

[0004] 5G-NR, also simply referred to as NR, provides, as compared to LTE, a higher capacity for a higher density of mobile broadband users, while also supporting device-to-device, ultra-reliable, and massive machine type communications with lower latency and / or lower battery consumption. Further, NR may allow for more flexible UE scheduling as compared to current LTE.Consequently, efforts are being made in ongoing developments of 5G-NR to take advantage of higher throughputs possible at higher frequencies.SUMMARY

[0005] Embodiments relate to wireless communications, and more particularly to apparatuses, systems, and methods for an apparatus of a user equipment (UE) comprising one or more processors, coupled to a memory, configured to: transmit a PDU session establishment request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a Session Management (SM) capability information element; and receive a PDU session establishment accept request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a SM network feature support information element.

[0006] Other embodiments relate to an apparatuses, systems, and methods for an apparatus of a user equipment (UE) comprising one or more processors, coupled to a memory, configured to: transmit a PDN connectivity request including a requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network; and receive an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is accepted in a Protocol configuration options (PCO).

[0007] Other embodiments relate to an apparatuses, systems, and methods for an apparatus of a user equipment (UE) comprising one or more processors, coupled to a memory, configured to: transmit a PDN connectivity request including a first requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network; receiving an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is not accepted in a Protocol configuration options (PCO); and transmitting a PDN connectivity request including a second requested Session and Service Continuity(SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network.

[0008] Other embodiments relate to an apparatuses, systems, and methods for an apparatus of a user equipment (UE) comprising one or more processors, coupled to a memory, configured to: transmit a PDU session modification request including a requested Session and Service Continuity (SSC) mode to a 5G or 6G core network; and receive a PDU session modification accept indicating that the requested SSC mode is accepted.

[0009] Other embodiments relate to an apparatuses, systems, and methods for an apparatus comprising one or more processors, coupled to a memory, configured to: receive a PDU session establishment request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a Session Management (SM) capability information element; and transmit a PDU session establishment accept request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a SM network feature support information element.

[0010] Other embodiments relate to an apparatuses, systems, and methods for an apparatus comprising one or more processors, coupled to a memory, configured to: receive a PDN connectivity request including a requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element; and transmit an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is accepted in a Protocol configuration options (PCO).

[0011] Other embodiments relate to an apparatuses, systems, and methods for an apparatus comprising one or more processors, coupled to a memory, configured to: receive a PDN connectivity request including a first requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element; transmit an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is not accepted in a Protocol configuration options (PCO); and receivea PDN connectivity request including a second requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element.

[0012] Other embodiments relate to an apparatuses, systems, and methods for an apparatus comprising one or more processors, coupled to a memory, configured to: receive a PDU session modification request including a requested Session and Service Continuity (SSC) mode; and transmit a PDU session modification accept indicating that the requested SSC mode is accepted.

[0013] The techniques described herein may be implemented in and / or used with a number of different types of devices, including but not limited to unmanned aerial vehicles (UAVs), unmanned aerial controllers (UACs), base stations, access points, cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

[0014] This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following Detailed Description, Figures, and Claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A better understanding of the present subject matter can be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0016] FIG. 1 A illustrates an example wireless communication system according to some embodiments.

[0017] FIG. 1 B illustrates an example of a base station and an access point in communication with a user equipment (UE) device, according to some embodiments.

[0018] FIG. 2 illustrates an example block diagram of a base station, according to some embodiments.

[0019] FIG. 3 illustrates an example block diagram of a server according to some embodiments.

[0020] FIG. 4 illustrates an example block diagram of a UE according to some embodiments.

[0021] FIG. 5 illustrates an example block diagram of cellular communication circuitry, according to some embodiments.

[0022] FIG. 6 illustrates an example of a baseband processor architecture for a UE, according to some embodiments.

[0023] FIG. 7 illustrates an example block diagram of an interface of baseband circuitry according to some embodiments.

[0024] FIG. 8 illustrates an example of a control plane protocol stack in accordance with some embodiments.

[0025] FIG. 9 illustrates an example of a user plane protocol stack in accordance with some embodiments.

[0026] FIG. 10 illustrates an example architecture of a system including a core network (CN) in accordance with some embodiments.

[0027] FIG. 11 illustrates an example architecture of a system including a core network (CN) in accordance with some embodiments.

[0028] FIG. 12 illustrates an example diagram showing PDN connectivity communication between user equipment and an EPC and PDU session communication between user equipment and a 5GS according to some embodiments.

[0029] FIG. 13 illustrates an example diagram showing PDN connectivity communication between user equipment and an EPC and PDU session communication between user equipment and a 5GS according to some embodiments.

[0030] FIG. 14 illustrates an example of a 5G SM capability information element according to some embodiments.

[0031] FIG. 15 illustrates an example of a 5G SM capability information element according to some embodiments.

[0032] FIG. 16 illustrates an example of a 5G SM network feature support information element according to some embodiments.

[0033] FIG. 17 illustrates an example diagram showing PDU session communication between user equipment and a 5GS and PDN connectivity communication between user equipment and an EPC according to some embodiments.

[0034] FIG. 18 illustrates an example diagram showing PDU session communication between user equipment and a 5GS according to some embodiments.

[0035] FIG. 19 illustrates an example diagram showing PDU session communication between user equipment and a 5GS and PDN connectivity communication between user equipment and an EPC according to some embodiments.

[0036] FIG. 20 illustrates a flow chart of a method for establishing a Packet Data Unit (PDU) session, according to some embodiments.

[0037] While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.DETAILED DESCRIPTIONTerms

[0038] The following is a glossary of terms used in this disclosure:

[0039] Memory Medium - Any of various types of non-transitory memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device; a computer system memory or random-access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash, magnetic media, e.g., a hard drive, or optical storage; registers, or other similar types of memory elements, etc. The memory medium may include other types of non- transitory memory as well or combinations thereof. In addition, the memory medium may be located in a first computer system in which the programs are executed, or may be located in a second different computer system which connects to the first computer system over a network, such as the Internet. In the latter instance, the second computer system may provide program instructions to the first computer for execution. The term “memory medium” may include two or more memory mediums which may reside in different locations, e.g., in different computer systems that are connected over a network. The memory medium may store program instructions (e.g., embodied as computer programs) that may be executed by one or more processors.

[0040] Carrier Medium - a memory medium as described above, as well as a physical transmission medium, such as a bus, network, and / or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

[0041] Programmable Hardware Element includes various hardware devices comprising multiple programmable function blocks connected via a programmable interconnect. Examples include FPGAs (Field Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs (Field Programmable Object Arrays), and CPLDs (Complex PLDs). The programmable function blocks may range from fine grained (combinatorial logic or look up tables) to coarse grained (arithmetic logic units or processor cores). A programmable hardware element may also be referred to as "reconfigurable logic”.

[0042] Computer System (or Computer) - any of various types of computing or processing systems, including a personal computer system (PC), mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing system, or other device or combinations of devices. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0043] User Equipment (UE) (or “UE Device”) - any of various types of computer systems devices which are mobile or portable and which performs wireless communications. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone™, Android™-based phones), portable gaming devices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™, iPhone™), laptops, wearable devices (e.g., smart watch, smart glasses), PDAs, portable Internet devices, music players, data storage devices, other handheld devices, unmanned aerial vehicles (UAVs) (e.g., drones), UAV controllers (UACs), and so forth. In general, the term “UE” or “UE device” can be broadly defined to encompass any electronic, computing, and / or telecommunications device (or combination of devices) which is easily transported by a user and capable of wireless communication.

[0044] Base Station - The term "Base Station" has the full breadth of its ordinary meaning, and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

[0045] Processing Element (or Processor) - refers to various elements or combinations of elements that are capable of performing a function in a device, such as a user equipment or a cellular network device. Processing elements may include, for example: processors and associated memory, portions or circuits of individual processor cores, entire processor cores, processor arrays, circuits such as an ASIC (Application Specific Integrated Circuit), programmable hardware elements such as a field programmable gate array (FPGA), as well any of various combinations of the above.

[0046] Channel - a medium used to convey information from a sender (transmitter) to a receiver. It should be noted that since characteristics of the term “channel” may differ according to different wireless protocols, the term “channel” as used herein may be considered as being used in a manner that is consistent with the standard of the type of device with reference to which the term is used. In some standards, channel widths may be variable (e.g., depending on device capability, band conditions, etc.). For example, LTE may support scalable channel bandwidths from 1.4 MHz to 20MHz. 5G NR can support scalable channel bandwidths from 5 MHz to 100 MHz in Frequency Range 1 (FR1 ) and up to 400 MHz in FR2. In other radio access technologies, WLAN channels may be 22 MHz wide while Bluetooth channels may be 1 MHz wide. Other protocols and standards may include different definitions of channels. Furthermore, some standards may define and use multiple types of channels, e.g., different channels for uplink or downlink and / or different channels for different uses such as data, control information, etc.

[0047] Band - The term "band" has the full breadth of its ordinary meaning, and at least includes a section of spectrum (e.g., radio frequency spectrum) in which channels are used or set aside for the same purpose.

[0048] Automatically - refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuitry, programmable hardware elements, ASICs, etc.), without user input directly specifying or performing the action or operation. Thus, the term "automatically" is in contrast to an operation being manually performed or specified by the user, where the user provides input to directly perform the operation. An automatic procedure may be initiated by input provided by the user, but the subsequent actions that are performed “automatically” are not specified by the user, i.e., are not performed “manually”, where the user specifies each action to perform. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting check boxes, radio selections, etc.) is filling out the form manually, even though the computer system will update the form in response to the user actions. The formmay be automatically filled out by the computer system where the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user input specifying the answers to the fields. As indicated above, the user may invoke the automatic filling of the form, but is not involved in the actual filling of the form (e.g., the user is not manually specifying answers to fields but rather they are being automatically completed). The present specification provides various examples of operations being automatically performed in response to actions the user has taken.

[0049] Approximately - refers to a value that is almost correct or exact. For example, approximately may refer to a value that is within 1 to 10 percent of the exact (or desired) value. It should be noted, however, that the actual threshold value (or tolerance) may be application dependent. For example, in some embodiments, “approximately” may mean within 0.1 % of some specified or desired value, while in various other embodiments, the threshold may be, for example, 2%, 3%, 5%, and so forth, as desired or as set by the particular application.

[0050] Concurrent - refers to parallel execution or performance, where tasks, processes, or programs are performed in an at least partially overlapping manner. For example, concurrency may be implemented using “strong” or strict parallelism, where tasks are performed (at least partially) in parallel on respective computational elements, or using “weak parallelism”, where the tasks are performed in an interleaved manner, e.g., by time multiplexing of execution threads.

[0051] Legacy - The 3rd Generation Partnership Project (3GPP) produces specifications that define 3GPP technologies. 3GPP specifications cover cellular telecommunications technologies, including radio access, core network and service capabilities, which provide a complete system description for mobile telecommunications. 3GPP uses a system of parallel “Releases” that provide developers with a stable platform for the implementation of features at a given point and then allow for the addition of new functionality in subsequent releases. Release 17 was released in 2022. Release 18 (Rel-18), at the time of this disclosure, is nearing release as its specifications have been largely defined. Accordingly,implementations and concepts compatible with Rel-18, or previous Releases, are sometimes referred to herein as “Legacy.” One or more embodiments of the present disclosure may be adopted in future Releases, e.g., Release 19.

[0052] rN - As used herein rN, when used in conjunction with an Information Element (IE) refers to a UE that is capable of supporting 3GPP Release N. For example, r18 denotes a UE capable of supporting 3GPP release 18. A UE that is capable of supporting a release greater than N may also be capable of supporting 3GPP Release N. A UE that is not capable of supporting 3GPP Release N may not be capable of supporting the lEs that include rN.

[0053] Various components may be described as “configured to” perform a task or tasks. In such contexts, “configured to” is a broad recitation generally meaning “having structure that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently performing that task (e.g., a set of electrical conductors may be configured to electrically connect a module to another module, even when the two modules are not connected). In some contexts, “configured to” may be a broad recitation of structure generally meaning “having circuitry that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently on. In general, the circuitry that forms the structure corresponding to “configured to” may include hardware circuits.

[0054] Various components may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase “configured to.” Reciting a component that is configured to perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f) interpretation for that component.

[0055] The example embodiments may be further understood with reference to the following description and the related appended drawings, wherein like elements are provided with the same reference numerals. The example embodiments relate to user equipment (UE)-initiated beam reporting (UIBR) using configured grant (UL) resources by a UE for frequency range two (FR2).

[0056] The example embodiments are described with regard to communication between a base station (e.g., next generation Node B (gNB)) and a user equipment (UE). However, reference to a gNB or a UE is merely provided for illustrative purposes. The example embodiments may be utilized with any electronic component that may establish a connection to a network and is configured with the hardware, software, and / or firmware to provide and support for performing interradio access technology (INTER-RAT) Long-Term Evolution (LTE) measurements without measurement gap by a user equipment (UE). Therefore, the gNB or UE as described herein is used to represent any appropriate type of electronic component.

[0057] The example embodiments are also described with regard to a fifth generation (5G) New Radio (NR) network that may configure a UE to perform INTER-RAT LTE measurements without measurement gap. However, reference to a 5G NR network is merely provided for illustrative purposes. The example embodiments may be utilized with any appropriate type of network.

[0058] Throughout this description various information elements (lEs) are referred to by specific names. It should be understood that these names are only examples and the lEs carrying the information referred to throughout this description may be referred to by other names by various entities.Figures 1 A and 1 B: Communication Systems

[0059] FIG. 1 A illustrates a simplified example wireless communication system, according to some embodiments. It is noted that the system of FIG. 1 A is merely one example of a possible system, and that features of this disclosure may be implemented in any of various systems, as desired.

[0060] As shown, the example wireless communication system includes a base station 102A which communicates over a transmission medium with one or more user devices 106A, 106B, etc., through 106N. Each of the user devices may be referred to herein as a “user equipment” (UE). Thus, the user devices 106 are referred to as UEs or UE devices.

[0061] The base station (BS) 102A may be a base transceiver station (BTS) or cell site (a “cellular base station”) and may include hardware that enables wireless communication with the UEs 106A through 106N.

[0062] The communication area (or coverage area) of the base station may be referred to as a “cell.” The base station 102A and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), 5G new radio (5G NR), HSPA, 3GPP2 CDMA2000 (e.g., 1 xRTT, 1 xEV-DO, HRPD, eHRPD), etc. Note that if the base station 102A is implemented in the context of LTE, also referred to as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN, it may alternately be referred to as an 'eNodeB' or ‘eNB’. Note that if the base station 102A is implemented in the context of 5G NR, it may alternately be referred to as ‘gNodeB’ or ‘gNB’.

[0063] As shown, the base station 102A may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), and / or the Internet, among various possibilities). Thus, the base station 102A may facilitate communication between the user devices and / or between the user devices and the network 100. In particular, the cellular base station 102A may provide UEs 106 with various telecommunication capabilities, such as voice, SMS and / or data services.

[0064] Base station 102A and other similar base stations (such as base stations 102B...102N) operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 106A-N and similar devices over a geographic area via one or more cellular communication standards.

[0065] Thus, while base station 102A may act as a “serving cell” for UEs 106A-N as illustrated in FIG. 1A, each UE 106 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which might be provided by base stations 102B-N and / or any other base stations), which may be referred to as “neighboring cells”. Such cells may also be capable of facilitating communication between user devices and / or between user devices and the network 100. Such cells may include “macro” cells, “micro” cells, “pico” cells, and / or cells which provide any of various other granularities of service area size. For example, base stations 102A-B illustrated in FIG. 1 A might be macro cells, while base station 102N might be a micro cell. Other configurations are also possible.

[0066] In some embodiments, base station 102A may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and / or to a NR core (NRC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs.

[0067] Note that a UE 106 may be capable of communicating using multiple wireless communication standards. For example, the UE 106 may be configured to communicate using a wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE- A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g., 1 xRTT, 1 xEV-DO, HRPD, eHRPD), etc.). The UE 106 may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M / H or DVB- H), and / or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0068] FIG. 1 B illustrates user equipment 106 (e.g., one of the devices 106Athrough 106N) in communication with a base station 102 and an access point 112, according to some embodiments. The UE 106 may be a device with both cellular communication capability and non-cellular communication capability (e.g., Bluetooth, Wi-Fi, and so forth) such as a mobile phone, a hand-held device, a computer or a tablet, or virtually any type of wireless device.

[0069] The UE 106 may include a processor that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 may include a programmable hardware element such as an FPGA (field-programmable gate array) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

[0070] The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE 106 may be configured to communicate using, for example, CDMA2000 (1 xRTT / 1 xEV-DO I HRPD I eHRPD), LTE / LTE- Advanced, or 5G NR using a single shared radio and / or GSM, LTE, LTE-Advanced, or 5G NR using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 106 may share one or more parts of a receive and / or transmit chain between multiple wireless communication technologies, such as those discussed above.

[0071] In some embodiments, the UE 106 may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 106 may include one or more radios which areshared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 106 might include a shared radio for communicating using either of LTE or 5G NR (or LTE or IxRTTor LTE or GSM), and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.FIG. 2: Block Diagram of a Base Station

[0072] FIG. 2 illustrates an example block diagram of a base station 102, according to some embodiments. It is noted that the base station of FIG. 2 is merely one example of a possible base station. As shown, the base station 102 may include processor(s) 204 which may execute program instructions for the base station 102. The processor(s) 204 may also be coupled to memory management unit (MMU) 240, which may be configured to receive addresses from the processor(s) 204 and translate those addresses to locations in memory (e.g., memory 260 and read only memory (ROM) 250) or to other circuits or devices.

[0073] The base station 102 may include at least one network port 270. The network port 270 may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices 106, access to the telephone network as described above in Figures 1 and 2.

[0074] The network port 270 (or an additional network port) may also or alternatively be configured to couple to a cellular network, e.g., a core network of a cellular service provider. The core network may provide mobility related services and / or other services to a plurality of devices, such as UE devices 106. In some cases, the network port 270 may couple to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider).

[0075] In some embodiments, base station 102 may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In such embodiments, base station 102 may be connected to a legacy evolved packet core(EPC) network and / or to a NR core (NRC) network. In addition, base station 102 may be considered a 5G NR cell and may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs.

[0076] The base station 102 may include at least one antenna 234, and possibly multiple antennas. The at least one antenna 234 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE devices 106 via radio 230. The antenna 234 communicates with the radio 230 via communication chain 232. Communication chain 232 may be a receive chain, a transmit chain or both. The radio 230 may be configured to communicate via various wireless communication standards, including, but not limited to, 5G NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0077] The base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some instances, the base station 102 may include multiple radios, which may enable the base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, the base station 102 may include an LTE radio for performing communication according to LTE as well as a 5G NR radio for performing communication according to 5G NR. In such a case, the base station 102 may be capable of operating as both an LTE base station and a 5G NR base station. As another possibility, the base station 102 may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0078] As described further subsequently herein, the BS 102 may include hardware and software components for implementing or supporting implementation of features described herein. The processor 204 of the base station 102 may be configured to implement or support implementation of part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 204 may be configured as a programmable hardwareelement, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit), or a combination thereof. Alternatively (or in addition) the processor 204 of the BS 102, in conjunction with one or more of the other components 230, 232, 234, 240, 250, 260, 270 may be configured to implement or support implementation of part or all of the features described herein.

[0079] In addition, as described herein, processor(s) 204 may be comprised of one or more processing elements. In other words, one or more processing elements may be included in processor(s) 204. Thus, processor(s) 204 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor(s) 204. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 204.

[0080] Further, as described herein, radio 230 may be comprised of one or more processing elements. In other words, one or more processing elements may be included in radio 230. Thus, radio 230 may include one or more integrated circuits (ICs) that are configured to perform the functions of radio 230. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of radio 230.

[0081] In some embodiments, the base station or gNB 102, and / or processors 204 thereof, can be capable of and configured to encode, for transmission to a user equipment (UE) using radio resource control signaling, configuration information for allocating configured-grant physical uplink shared channel resources (CG- PUSCH) to notify a UIBR procedure is triggered at the UE side to enable the UE to: select, at the UE, a reference signal (RS) resource to be monitored by the UE to identify whether the UIBR is triggered at the UE; monitor, by the UE, a signal quality of the selected RS resource; determine, by the UE, the signal quality is less than a signal quality threshold; and measure a channel state information reference signal (RS) resource set based on determining the signal quality is less than a signal quality threshold; and decode, from the UE, beam management reports to notify the UIBR procedure is triggered using the CG-PUSCH resource based on based on the measurements of the CSI resource sets.FIG. 3: Block Diagram of a Server

[0082] FIG. 3 illustrates an example block diagram of a server 104, according to some embodiments. It is noted that the server of FIG. 3 is merely one example of a possible server. As shown, the server 104 may include processor(s) 344 which may execute program instructions for the server 104. The processor(s) 344 may also be coupled to memory management unit (MMU) 374, which may be configured to receive addresses from the processor(s) 344 and translate those addresses to locations in memory (e.g., memory 364 and read only memory (ROM) 354) or to other circuits or devices.

[0083] The server 104 may be configured to provide a plurality of devices, such as base station 102, and UE devices 106 access to network functions, e.g., as further described herein.

[0084] In some embodiments, the server 104 may be part of a radio access network, such as a 5G New Radio (5G NR) radio access network. In some embodiments, the server 104 may be connected to a legacy evolved packet core (EPC) network and / or to a NR core (NRC) network.

[0085] As described herein, the server 104 may include hardware and software components for implementing or supporting implementation of features described herein. The processor 344 of the server 104 may be configured to implement or support implementation of part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 344 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit), or a combination thereof. Alternatively (or in addition) the processor 344 of the server 104, in conjunction with one or more of the other components 354, 364, and / or 374 may be configured to implement or support implementation of part or all of the features described herein.

[0086] In addition, as described herein, processor(s) 344 may be comprised ofone or more processing elements. In other words, one or more processing elements may be included in processor(s) 344. Thus, processor(s) 344 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor(s) 344. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 344.FIG. 4: Block Diagram of a User Equipment

[0087] FIG. 4 illustrates an example simplified block diagram of a communication device 106, according to some embodiments. It is noted that the block diagram of the communication device of FIG. 4 is only one example of a possible communication device. According to embodiments, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, an unmanned aerial vehicle (UAV), a UAV controller (UAC) and / or a combination of devices, among other devices. As shown, the communication device 106 may include a set of components 400 configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOO), which may include portions for various purposes. Alternatively, this set of components 400 may be implemented as separate components or groups of components for the various purposes. The set of components 400 may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device 106.

[0088] For example, the communication device 106 may include various types of memory (e.g., including NAND flash 410), an input / output interface such as connector l / F 420 (e.g., for connecting to a computer system; dock; charging station; input devices, such as a microphone, camera, keyboard; output devices, such as speakers; etc.), the display 460, which may be integrated with or external to the communication device 106, and cellular communication circuitry 430 such asfor 5G NR, LTE, GSM, etc., and short to medium range wireless communication circuitry 429 (e.g., Bluetooth™ and WLAN circuitry). In some embodiments, communication device 106 may include wired communication circuitry (not shown), such as a network interface card, e.g., for Ethernet.

[0089] The cellular communication circuitry 430 may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 435 and 436 as shown. The short to medium range wireless communication circuitry 429 may also couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 437 and 438 as shown. Alternatively, the short to medium range wireless communication circuitry 429 may couple (e.g., communicatively; directly or indirectly) to the antennas 435 and 436 in addition to, or instead of, coupling (e.g., communicatively; directly or indirectly) to the antennas 437 and 438. The short to medium range wireless communication circuitry 429 and / or cellular communication circuitry 430 may include multiple receive chains and / or multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a multiple-input multiple output (MIMO) configuration.

[0090] In some embodiments, as further described below, cellular communication circuitry 430 may include dedicated receive chains (including and / or coupled to, e.g., communicatively; directly or indirectly, dedicated processors and / or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR). In addition, in some embodiments, cellular communication circuitry 430 may include a single transmit chain that may be switched between radios dedicated to specific RATs. For example, a first radio may be dedicated to a first RAT, e.g., LTE, and may be in communication with a dedicated receive chain and a transmit chain shared with an additional radio, e.g., a second radio that may be dedicated to a second RAT, e.g., 5G NR, and may be in communication with a dedicated receive chain and the shared transmit chain.

[0091] The communication device 106 may also include and / or be configured for use with one or more user interface elements. The user interface elements may include any of various elements, such as display 460 (which may be a touchscreen display), a keyboard (which may be a discrete keyboard or may be implemented aspart of a touchscreen display), a mouse, a microphone and / or speakers, one or more cameras, one or more buttons, and / or any of various other elements capable of providing information to a user and / or receiving or interpreting user input.

[0092] The communication device 106 may further include one or more smart cards 445 that include SIM (Subscriber Identity Module) functionality, such as one or more UICC(s) (Universal Integrated Circuit Card(s)) cards 445. Note that the term “SIM” or “SIM entity” is intended to include any of various types of SIM implementations or SIM functionality, such as the one or more UICC(s) cards 445, one or more eUlCCs, one or more eSIMs, either removable or embedded, etc. In some embodiments, the UE 106 may include at least two SIMs. Each SIM may execute one or more SIM applications and / or otherwise implement SIM functionality. Thus, each SIM may be a single smart card that may be embedded, e.g., may be soldered onto a circuit board in the UE 106, or each SIM 410 may be implemented as a removable smart card. Thus, the SIM(s) may be one or more removable smart cards (such as UICC cards, which are sometimes referred to as “SIM cards”), and / or the SIMs 410 may be one or more embedded cards (such as embedded UICCs (eUlCCs), which are sometimes referred to as “eSIMs” or “eSIM cards”). In some embodiments (such as when the SIM(s) include an eUlCC), one or more of the SIM(s) may implement embedded SIM (eSIM) functionality; in such an embodiment, a single one of the SIM(s) may execute multiple SIM applications. Each of the SIMs may include components such as a processor and / or a memory; instructions for performing SIM / eSIM functionality may be stored in the memory and executed by the processor. In some embodiments, the UE 106 may include a combination of removable smart cards and fixed / non-removable smart cards (such as one or more eUlCC cards that implement eSIM functionality), as desired. For example, the UE 106 may comprise two embedded SIMs, two removable SIMs, or a combination of one embedded SIMs and one removable SIMs. Various other SIM configurations are also contemplated.

[0093] As noted above, in some embodiments, the UE 106 may include two or more SIMs. The inclusion of two or more SIMs in the UE 106 may allow the UE 106 to support two different telephone numbers and may allow the UE 106 tocommunicate on corresponding two or more respective networks. For example, a first SIM may support a first RAT such as LTE, and a second SIM 410 support a second RAT such as 5G NR. Other implementations and RATs are of course possible. In some embodiments, when the UE 106 comprises two SIMs, the UE 106 may support Dual SIM Dual Active (DSDA) functionality. The DSDA functionality may allow the UE 106 to be simultaneously connected to two networks (and use two different RATs) at the same time, or to simultaneously maintain two connections supported by two different SIMs using the same or different RATs on the same or different networks. The DSDA functionality may also allow the UE 106 to simultaneously receive voice calls or data traffic on either phone number. In certain embodiments the voice call may be a packet switched communication. In other words, the voice call may be received using voice over LTE (VoLTE) technology and / or voice over NR (VoNR) technology. In some embodiments, the UE 106 may support Dual SIM Dual Standby (DSDS) functionality. The DSDS functionality may allow either of the two SIMs in the UE 106 to be on standby waiting for a voice call and / or data connection. In DSDS, when a call / data is established on one SIM, the other SIM is no longer active. In some embodiments, DSDx functionality (either DSDA or DSDS functionality) may be implemented with a single SIM (e.g., a eUlCC) that executes multiple SIM applications for different carriers and / or RATs.

[0094] As shown, the SOC 400 may include processor(s) 402, which may execute program instructions for the communication device 106 and display circuitry 404, which may perform graphics processing and provide display signals to the display 460. The processor(s) 402 may also be coupled to memory management unit (MMU) 440, which may be configured to receive addresses from the processor(s) 402 and translate those addresses to locations in memory (e.g., memory 406, read only memory (ROM) 450, NAND flash memory 410) and / or to other circuits or devices, such as the display circuitry 404, short to medium range wireless communication circuitry 429, cellular communication circuitry 430, connector l / F 420, and / or display 460. The MMU 440 may be configured to perform memory protection and page table translation or set up. In some embodiments, theMMU 440 may be included as a portion of the processor(s) 402.

[0095] As described herein, the communication device 106 may include hardware and software components for implementing the above features for a communication device 106 to communicate a scheduling profile for power savings to a network. The processor 402 of the communication device 106 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 402 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 402 of the communication device 106, in conjunction with one or more of the other components 400, 404, 406, 410, 420, 429, 430, 440, 445, 450, 460 may be configured to implement part or all of the features described herein.

[0096] In addition, as described herein, processor 402 may include one or more processing elements. Thus, processor 402 may include one or more integrated circuits (ICs) that are configured to perform the functions of processor 402. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processor(s) 402.

[0097] Further, as described herein, cellular communication circuitry 430 and short to medium range wireless communication circuitry 429 may each include one or more processing elements. In other words, one or more processing elements may be included in cellular communication circuitry 430 and, similarly, one or more processing elements may be included in short to medium range wireless communication circuitry 429. Thus, cellular communication circuitry 430 may include one or more integrated circuits (ICs) that are configured to perform the functions of cellular communication circuitry 430. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of cellular communication circuitry 430. Similarly, the short to medium range wireless communication circuitry 429 may include one or more ICs that are configured to perform the functions of short to medium range wirelesscommunication circuitry 429. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of short to medium range wireless communication circuitry 429.FIG. 5: Block Diagram of Cellular Communication Circuitry

[0098] FIG. 5 illustrates an example simplified block diagram of cellular communication circuitry, according to some embodiments. It is noted that the block diagram of the cellular communication circuitry of FIG. 5 is only one example of a possible cellular communication circuit. According to embodiments, cellular communication circuitry 530, which may be cellular communication circuitry 430, may be included in a communication device, such as communication device 106 described above. As noted above, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and / or a combination of devices, among other devices.

[0099] The cellular communication circuitry 530 may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 435a-b and 436 as shown (in FIG. 4). In some embodiments, cellular communication circuitry 530 may include dedicated receive chains (including and / or coupled to, e.g., communicatively; directly or indirectly, dedicated processors and / or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR). For example, as shown in FIG. 5, cellular communication circuitry 530 may include a modem 510 and a modem 520. Modem 510 may be configured for communications according to a first RAT, e.g., such as LTE or LTE-A, and modem 520 may be configured for communications according to a second RAT, e.g., such as 5G NR.

[0100] As shown, modem 510 may include one or more processors 512 and a memory 516 in communication with processors 512. Modem 510 may be in communication with a radio frequency (RF) front end 535. RF front end 535 mayinclude circuitry for transmitting and receiving radio signals. For example, RF front end 535 may include receive circuitry (RX) 532 and transmit circuitry (TX) 534. In some embodiments, receive circuitry 532 may be in communication with downlink (DL) front end 550, which may include circuitry for receiving radio signals via antenna 335a.

[0101] Similarly, modem 520 may include one or more processors 522 and a memory 526 in communication with processors 522. Modem 520 may be in communication with an RF front end 540. RF front end 540 may include circuitry for transmitting and receiving radio signals. For example, RF front end 540 may include receive circuitry 542 and transmit circuitry 544. In some embodiments, receive circuitry 542 may be in communication with DL front end 560, which may include circuitry for receiving radio signals via antenna 335b.

[0102] In some embodiments, a switch 570 may couple transmit circuitry 534 to uplink (UL) front end 572. In addition, switch 570 may couple transmit circuitry 544 to UL front end 572. UL front end 572 may include circuitry for transmitting radio signals via antenna 336. Thus, when cellular communication circuitry 530 receives instructions to transmit according to the first RAT (e.g., as supported via modem 510), switch 570 may be switched to a first state that allows modem 510 to transmit signals according to the first RAT (e.g., via a transmit chain that includes transmit circuitry 534 and UL front end 572). Similarly, when cellular communication circuitry 530 receives instructions to transmit according to the second RAT (e.g., as supported via modem 520), switch 570 may be switched to a second state that allows modem 520 to transmit signals according to the second RAT (e.g., via a transmit chain that includes transmit circuitry 544 and UL front end 572).

[0103] As described herein, the modem 510 may include hardware and software components for implementing the above features or for time division multiplexing UL data for NSA NR operations, as well as the various other techniques described herein. The processors 512 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 512 may be configured as aprogrammable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 512, in conjunction with one or more of the other components 530, 532, 534, 535, 550, 570, 572, 335a, 335b, and 336 may be configured to implement part or all of the features described herein.

[0104] In addition, as described herein, processors 512 may include one or more processing elements. Thus, processors 512 may include one or more integrated circuits (ICs) that are configured to perform the functions of processors 512. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processors 512.

[0105] The processors 522 may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor 522 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor 522, in conjunction with one or more of the other components 540, 542, 544, 550, 570, 572, 335a, 335b, and 336 may be configured to implement part or all of the features described herein.

[0106] In addition, as described herein, processors 522 may include one or more processing elements. Thus, processors 522 may include one or more integrated circuits (ICs) that are configured to perform the functions of processors 522. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processors 522.

[0107] In some embodiments, the processors 512, 522 can be configured for performing INTER-RAT LTE measurements without measurement gap, as further described herein.FIG. 6: Block Diagram of a Baseband Processor Architecture for a UE

[0108] FIG. 6 illustrates example components of a device 600 in accordancewith some embodiments. It is noted that the device of FIG. 6 is merely one example of a possible system, and that features of this disclosure may be implemented in any of various UEs, as desired.

[0109] In some embodiments, the device 600 may include application circuitry 602, baseband circuitry 604, Radio Frequency (RF) circuitry 606, front-end module (FEM) circuitry 608, one or more antennas 610, and power management circuitry (PMC) 612 coupled together at least as shown. The components of the illustrated device 600 may be included in a UE 106 or a RAN node 102A. In some embodiments, the device 600 may include less elements (e.g., a RAN node may not utilize application circuitry 602, and instead include a processor / controller to process IP data received from an EPC). In some embodiments, the device 600 may include additional elements such as, for example, memory / storage, display, camera, sensor, or input / output (I / O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C- RAN) implementations).

[0110] The application circuitry 602 may include one or more application processors. For example, the application circuitry 602 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory / storage and may be configured to execute instructions stored in the memory / storage to enable various applications or operating systems to run on the device 600. In some embodiments, processors of application circuitry 602 may process IP data packets received from an EPC.

[0111] The baseband circuitry 604 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 604 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 606 and to generate baseband signals for a transmit signal path of the RF circuitry 606.Baseband processing circuity 604 may interface with the application circuitry 602 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 606. For example, in some embodiments, the baseband circuitry 604 may include a third generation (3G) baseband processor 604A, a fourth generation (4G) baseband processor 604B, a fifth generation (5G) baseband processor 604C, or other baseband processor(s) 604D for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry 604 (e.g., one or more of baseband processors 604A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 606. In other embodiments, some or all of the functionality of baseband processors 604A-D may be included in modules stored in the memory 604G and executed via a Central Processing Unit (CPU) 604E. The radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some embodiments, modulation / demodulation circuitry of the baseband circuitry 604 may include Fast- Fourier Transform (FFT), precoding, or constellation mapping / demapping functionality. In some embodiments, encoding / decoding circuitry of the baseband circuitry 604 may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder / decoder functionality. Embodiments of modulation / demodulation and encoder / decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[0112] In some embodiments, the baseband circuitry 604 may include one or more audio digital signal processor(s) (DSP) 604F. The audio DSP(s) 604F may be include elements for compression / decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 604 and the application circuitry 602 may be implemented together such as, for example, on a system on a chip (SOC).

[0113] In some embodiments, the baseband circuitry 604 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 604 may support communication with an evolved universal terrestrial radio access network (EUTRAN) or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 604 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[0114] RF circuitry 606 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 606 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 606 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 608 and provide baseband signals to the baseband circuitry 604. RF circuitry 606 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 604 and provide RF output signals to the FEM circuitry 608 for transmission.

[0115] In some embodiments, the receive signal path of the RF circuitry 606 may include mixer circuitry 606a, amplifier circuitry 606b and filter circuitry 606c. In some embodiments, the transmit signal path of the RF circuitry 606 may include filter circuitry 606c and mixer circuitry 606a. RF circuitry 606 may also include synthesizer circuitry 606d for synthesizing a frequency for use by the mixer circuitry 606a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 606a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 608 based on the synthesized frequency provided by synthesizer circuitry 606d. The amplifier circuitry 606b may be configured to amplify the down-converted signals and the filter circuitry 606c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided tothe baseband circuitry 604 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a necessity. In some embodiments, mixer circuitry 606a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0116] In some embodiments, the mixer circuitry 606a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 606d to generate RF output signals for the FEM circuitry 608. The baseband signals may be provided by the baseband circuitry 604 and may be filtered by filter circuitry 606c.

[0117] In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may be configured for super-heterodyne operation.

[0118] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 606 may include analog- to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 604 may include a digital baseband interface to communicate with the RF circuitry 606.

[0119] In some dual-mode embodiments, a separate radio IC circuitry may beprovided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[0120] In some embodiments, the synthesizer circuitry 606d may be a fractional-N synthesizer or a fractional N / N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 606d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0121] The synthesizer circuitry 606d may be configured to synthesize an output frequency for use by the mixer circuitry 606a of the RF circuitry 606 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 606d may be a fractional N / N+1 synthesizer.

[0122] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a necessity. Divider control input may be provided by either the baseband circuitry 604 or the applications processor 602 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 602.

[0123] Synthesizer circuitry 606d of the RF circuitry 606 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0124] In some embodiments, synthesizer circuitry 606d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 606 may include an IQ / polar converter.

[0125] FEM circuitry 608 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 610, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 606 for further processing. FEM circuitry 608 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 606 for transmission by one or more of the one or more antennas 610. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry 606, solely in the FEM 608, or in both the RF circuitry 606 and the FEM 608.

[0126] In some embodiments, the FEM circuitry 608 may include a TX / RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 606). The transmit signal path of the FEM circuitry 608 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 606), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 610).

[0127] In some embodiments, the PMC 612 may manage power provided to the baseband circuitry 604. In particular, the PMC 612 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC 612 may often be included when the device 600 is capable of being powered by abattery, for example, when the device is included in a UE. The PMC 612 may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics.

[0128] While FIG. 6 shows the PMC 612 coupled only with the baseband circuitry 604, in other embodiments the PMC 612 may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry 602, RF circuitry 606, or FEM 608.

[0129] In some embodiments, the PMC 612 may control, or otherwise be part of, various power saving mechanisms of the device 600. For example, if the device 600 is in a radio resource control_Connected (RRC_Connected) state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device 600 may power down for brief intervals of time and thus save power.

[0130] If there is no data traffic activity for an extended period of time, then the device 600 may transition off to an RRCJdle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device 600 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device 600 may not receive data in this state, in order to receive data, it will transition back to RRCJDonnected state.

[0131] An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

[0132] Processors of the application circuitry 602 and processors of the baseband circuitry 604 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 604, aloneor in combination, may be used execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry 604 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 (L3) may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 (L2) may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 (L1 ) may comprise a physical (PHY) layer of a UE / RAN node, described in further detail below. Accordingly, the baseband circuitry 604 can be used to encode a message for transmission between a UE and a gNB, or decode a message received between a UE and a gNB.FIG. 7: Block Diagram of an Interface of Baseband Circuitry

[0133] FIG. 7 illustrates example interfaces of baseband circuitry in accordance with some embodiments. It is noted that the baseband circuitry of FIG. 7 is merely one example of a possible circuitry, and that features of this disclosure may be implemented in any of various systems, as desired.

[0134] As discussed above, the baseband circuitry 604 of FIG. 6 may comprise processors 604A-604E and a memory 604G utilized by said processors. Each of the processors 604A-604E may include a memory interface, 704A-704E, respectively, to send / receive data to / from the memory 604G.

[0135] The baseband circuitry 604 may further include one or more interfaces to communicatively couple to other circuitries / devices, such as a memory interface 712 (e.g., an interface to send / receive data to / from memory external to the baseband circuitry 604), an application circuitry interface 714 (e.g., an interface to send / receive data to / from the application circuitry 602 of FIG. 6), an RF circuitry interface 716 (e.g., an interface to send / receive data to / from RF circuitry 606 of FIG. 6), a wireless hardware connectivity interface 718 (e.g., an interface tosend / receive data to / from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface 720 (e.g., an interface to send / receive power or control signals to / from the PMC 612.FIG. 8: Control Plane Protocol Stack

[0136] FIG. 8 is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane 800 is shown as a communications protocol stack between the UE 106a (or alternatively, the UE 106b), the RAN node 102A (or alternatively, the RAN node 102B), and the mobility management entity (MME) 621 .

[0137] The PHY layer 801 may transmit or receive information used by the MAC layer 802 over one or more air interfaces. The PHY layer 801 may further perform link adaptation or adaptive modulation and coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers, such as the RRC layer 805. The PHY layer 801 may still further perform error detection on the transport channels, forward error correction (FEC) coding / decoding of the transport channels, modulation / demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and Multiple Input Multiple Output (MIMO) antenna processing.

[0138] The MAC layer 802 may perform mapping between logical channels and transport channels, multiplexing of MAC service data units (SDUs) from one or more logical channels onto transport blocks (TB) to be delivered to PHY via transport channels, de-multiplexing MAC SDUs to one or more logical channels from transport blocks (TB) delivered from the PHY via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), and logical channel prioritization.

[0139] The RLC layer 803 may operate in a plurality of modes of operation,including: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer 803 may execute transfer of upper layer protocol data units (PDUs), error correction through automatic repeat request (ARQ) for AM data transfers, and concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC layer 803 may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment.

[0140] The PDCP layer 804 may execute header compression and decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform insequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re-establishment of lower layers for radio bearers mapped on RLC AM, cipher and decipher control plane data, perform integrity protection and integrity verification of control plane data, control timerbased discard of data, and perform security operations (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.).

[0141] The main services and functions of the RRC layer 805 may include broadcast of system information (e.g., included in Master Information Blocks (MIBs) or System Information Blocks (SIBs) related to the non-access stratum (NAS)), broadcast of system information related to the access stratum (AS), paging, establishment, maintenance and release of an RRC connection between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point Radio Bearers, security functions including key management, inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting. Said MIBs and SIBs may comprise one or more information elements (lEs), which may each comprise individual data fields or data structures.

[0142] The UE 601 and the RAN node 102A may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack comprisingthe PHY layer 801 , the MAC layer 802, the RLC layer 803, the PDCP layer 804, and the RRC layer 805.

[0143] The non-access stratum (NAS) protocols 806 form the highest stratum of the control plane between the UE 601 and the MME 621. The NAS protocols 806 support the mobility of the UE 601 and the session management procedures to establish and maintain IP connectivity between the UE 601 and the P-GW 623 (shown in FIG. 9).

[0144] The S1 Application Protocol (S1 -AP) layer 815 may support the functions of the S1 interface and comprise Elementary Procedures (EPs). An EP is a unit of interaction between the RAN node 102A and the CN 1020 (shown in FIG. 10). The S1 -AP layer services may comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN Information Management (RIM), and configuration transfer.

[0145] The Stream Control Transmission Protocol (SCTP) layer (alternatively referred to as the SCTP / IP layer) 814 may ensure reliable delivery of signaling messages between the RAN node 102A and the MME 621 based, in part, on the IP protocol, supported by the IP layer 813. The L2 layer 812 and the L1 layer 81 1 may refer to communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information.

[0146] The RAN node 102A and the MME 621 may utilize an S1 -MME interface to exchange control plane data via a protocol stack comprising the L1 layer 81 1 , the L2 layer 812, the IP layer 813, the SCTP layer 814, and the S1 -AP layer 815.FIG. 9: User Plane Protocol Stack

[0147] FIG. 9 is an illustration of an example of a user plane protocol stack in accordance with some embodiments. In this embodiment, a user plane 900 is shown as a communications protocol stack between the UE 106A (or alternatively, the UE 106B or 106N), the RAN node 102A (or alternatively, the RAN node 102B),the S-GW 622, and the P-GW 623. The user plane 900 may utilize at least some of the same protocol layers as the control plane 800. For example, the UE 601 and the RAN node 102A may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange user plane data via a protocol stack comprising the PHY layer 801 , the MAC layer 802, the RLC layer 803, the PDCP layer 804.

[0148] The General Packet Radio Service (GPRS) Tunneling Protocol for the user plane (GTP-U) layer 904 may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats, for example. The UDP and IP security (UDP / IP) layer 903 may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN node 102A and the S-GW 622 may utilize an S1 -U interface to exchange user plane data via a protocol stack comprising the L1 layer 81 1 , the L2 layer 812, the UDP / IP layer 903, and the GTP-U layer 904. The S-GW 622 and the P-GW 623 may utilize an S5 / S8a interface to exchange user plane data via a protocol stack comprising the L1 layer 811 , the L2 layer 812, the UDP / IP layer 903, and the GTP- U layer 904. As discussed above with respect to FIG. 8, NAS protocols support the mobility of the UE 106 and the session management procedures to establish and maintain IP 913 connectivity between the UE 106 and the P-GW 623.FIG. 10: Core Network

[0149] FIG. 10 illustrates an example architecture of a 5G system 1000 including a 5G core network (CN) 1020, also referred to as 5GC, in accordance with various embodiments. The CN 1020 may be a core network for a 5G System (which may be referred to as a 5GS). The 5G system 1000 is shown to include a UE 1001 , which may be the same or similar to the UEs 106A, 106B, or 106N discussed previously; a (R)AN 1010, which may be the same or similar to the BSs 102A or 102N discussed previously; and a data network (DN) 1003, which may be, for example, operator services, Internet access, or 3rd party services; and a CN1020. The CN 1020 may include a number of network functions including an Authentication Server Function (AUSF) 1022; an Access and Mobility Management Function (AMF) 1021 ; a Session Management Function (SMF) 1024; a Network Exposure Function (NEF) 1023; a Policy Control Function (PCF) 1026; a Network Repository Function (NRF) 1025; a Unified Data Management (UDM) 1027; an Application Function (AF) 1028; a User Plane Function (UPF) 1002; and a Network Slice Selection Function (NSSF) 1029. These network functions may be implemented, in some cases, as virtualized software-based functions / services.

[0150] The UPF 1002 may act as an anchor point for intra-RAT and inter-RAT mobility, an external packet data unit (PDU) session point of interconnect to DN 1003, and a branching point to support mufti-homed PDU session. A PDU session is a logical connection between the UE and the DN. The UPF 1002 may also perform packet routing and forwarding, perform packet inspection, enforce the user plane part of policy rules, lawfully intercept packets (user plane (UP) collection), perform traffic usage reporting, perform quality of service (QoS) handling for a user plane (e.g., packet filtering, gating, UL / DL rate enforcement), perform Uplink Traffic verification (e.g., Service Data Flows (SDF) to QoS flow mapping), transport level packet marking in the uplink and downlink, and perform downlink packet buffering and downlink data notification triggering. UPF 1002 may include an uplink classifier to support routing traffic flows to a data network, The DN 1003 may represent various network operator services, Internet access, or third-party services. DN 1003 may include, or be similar to, application server 104 discussed previously. The UPF 1002 may interact with the SMF 1024 via an N4 reference point between the SMF 1024 and the UPF 1002.

[0151] The AUSF 1022 may store data for authentication of UE 1001 and handle authentication-related functionality, The AUSF 1022 may facilitate a common authentication frame work for various access types. The AUSF 1022 may communicate with the AMF 1021 via an N12 reference point between the AMF 1021 and the AUSF 1022; and may communicate with the UDM 1027 via an N13 reference point between the UDM 1027 and the AUSF 1022. Additionally, the AUSF 1022 may exhibit an Nausf service-based interface.

[0152] The AMF 1021 may be responsible for registration management (e.g., for registering UE 1001 , etc.), connection management, reachability management, mobility management, and lawful interception of A MF- related events, and access authentication and authorization. The AMF 1021 may be a termination point for an N1 1 reference point between the AMF 1021 and the SMF 1024. The AMF 1021 may provide transport for SM messages between the UE 1001 and the SMF 1024, and act as a transparent proxy for routing SM messages. AMF 1021 may also provide transport for Short Message Service (SMS) messages between UE 1001 and an SMSF (not shown by FIG. 10). AMF 1021 may act as a security anchor function (SEAF), which may include interaction with the AUSF 1022 and the UE 1001 , receipt of an intermediate key that was established as a result of the UE 1001 authentication process. Where Universal Subscriber Identity Module (USIM) based authentication is used, the AMF 1021 may retrieve the security material from the AUSF 1022. AMF 1021 may also include a Security Context Management (SCM) function, which receives a key from the SEAF that it uses to derive accessnetwork specific keys. Furthermore, AMF 1021 may be a termination point of a RAN control plane (CP) interface, which may include or be an N2 reference point between the (R)AN 1010 and the AMF 1021 ; and the AMF 1021 may be a termination point of NAS (Nl) signaling and perform NAS ciphering and integrity protection.

[0153] AMF 1021 may also support NAS signaling with a UE 1001 over a non- 3GPP Inter-Working Function (N3IWF) interface. The N3IWF may be used to provide access to untrusted entities. N3IWF may be a termination point for the N2 interface between the (R)AN 1010 and the AMF 1021 for the control plane and may be a termination point for the N3 reference point between the (R)AN 1010 and the UPF 1002 for the user plane. As such, the AMF 1021 may handle N2 signaling from the SMF 1024 and the AMF 1021 for PDU sessions and encapsulate / de- encapsulate packets for IPSec and N3 tunneling, mark N3 user-plane packets in the uplink, and enforce QoS corresponding to N3 packet marking while considering QoS requirements associated with such marking received over N2. N3IWF may also relay uplink and downlink control plane non-access stratum (NAS) signalingbetween the UE 1001 and AMF 1021 via an N1 reference point between the UE 1001 and the AMF 1021 , and relay uplink and downlink user-plane packets between the UE 1001 and UPF 1002. The N3IWF also provides mechanisms for internet protocol security (IPsec) tunnel establishment with the UE 1001 . The AMF 1021 may exhibit an Namf service based interface and may be a termination point for an N14 reference point between two AMFs 1021 and an N17 reference point between the AMF 1021 and a 5G Equipment Identity Register (5G-EIR) (not shown by FIG. 10).

[0154] The UE 1001 may need to register with the AMF 1021 in order to receive network services. Registration Management (RM) is used to register or deregister the UE 1001 with the network (e.g., AMF 1021 ), and establish a UE context in the network (e.g., AMF 1021 ). The UE 1001 may operate in an RM-REGISTERED state or an RM-DEREGISTERED state. In the RM-DEREGISTERED state, the UE 1001 is not registered with the network, and the UE context in AMF 1021 holds no valid location or routing information for the UE 1001 so the UE 1001 is not reachable by the AMF 1021. In the RM REGISTERED state, the UE 1001 is registered with the network, and the UE context in AMF 1021 may hold a valid location or routing information for the UE 1001 so the UE 1001 is reachable by the AMF 1021. In the RM-REGISTERED state, the UE 1001 may perform mobility registration update procedures, perform periodic registration update procedures triggered by expiration of the periodic update timer (e.g., to notify the network that the UE 1001 is still active), and perform a Registration Update procedure to update UE capability information or to re-negotiate protocol parameters with the network, among others.

[0155] The AMF 1021 may store one or more RM contexts for the UE 1001 , where each RM context is associated with a specific access to the network. The RM context may be a data structure, database object, etc. that indicates or stores, inter glia, a registration state per access type and the periodic update timer. The AMF 1021 may also store a 5GC mobility management (MM) context that may be the same or similar to the evolved packet services (EPS) Mobility Management (E)MM context discussed previously. In variousembodiments, the AMF 1021 may store a CE mode B Restriction parameter of the UE 1001 in an associated MM context or registration management (RM) context. The AMF 1021 may also derive the value, when needed, from the UE's usage setting parameter already stored in the UE context (and / or MM / RM context).

[0156] Connection Management (CM) may be used to establish and release a signaling connection between the UE 1001 and the AMF 1021 over the N1 interface. The signaling connection is used to enable NAS signaling exchange between the UE 1001 and the CN 1020 and comprises both the signaling connection between the UE and the AN (e.g., RRC connection or UE-N3IWF connection for non-3GPP access) and the N2 connection for the UE 1001 between the AN (e.g., AN 1010) and the AMF 1021. The UE 1001 may operate in one of two CM states, CM-IDLE mode or CM-CONNECTED mode. When the UE 1001 is operating in the CM-IDLE state / mode, the UE 1001 may have no NAS signaling connection established with the AMF 1021 over the N1 interface, and there may be (R)AN 1010 signaling connection (e.g., N2 and / or N3 connections) for the UE 1001. When the UE 1001 is operating in the CM-CONNECTED state / mode, the UE 1001 may have an established NAS signaling connection with the AMF 1021 over the Nl interface, and there may be a (R)AN 1010 signaling connection (e.g., N2 and / or N3 connections) for the UE 1001. Establishment of an N2 connection between the (R)AN 1010 and the AMF 1021 may cause the UE 1001 to transition from CM-IDLE mode to CM-CONNECTED mode, and the UE 1001 may transition from the CM-CONNECTED mode to the CM-IDLE mode when N2 signaling between the (R)AN 1010 and the AMF 1021 is released.

[0157] The SMF 1024 may be responsible for session management (SM) session establishment, modify and release, including tunnel maintain between UPF and AN node); UE IP address allocation and management (including optional authorization); selection and control of UP function; configuring traffic steering at UPF to route traffic to proper destination; termination of interfaces toward policy control functions; controlling part of policy enforcement and QoS; lawful intercept (for SM events and interface to LI system); termination of SM parts of NAS messages; downlink data notification; initiating AN specific SM information, sentvia AMF over N2 to AN; and determining SSC mode of a session. SM may refer to management of a PDU session, and a PDU session or "session" may refer to a PDU connectivity service that provides or enables the exchange of PDUs between a UE 1001 and a data network (DN) 1003 identified by a Data Network Name (DNN). PDU sessions may be established upon UE 1001 request, modified upon UE 1001 and CN 1020 request, and released upon UE 1001 and CN 1020 request using NAS SM signaling exchanged over the N1 reference point between the UE 1001 and the SMF 1024. Upon request from an application server, the CN 1020 may trigger a specific application in the UE 1001. In response to receipt of the trigger message, the UE 1001 may pass the trigger message (or relevant parts / information of the trigger message) to one or more identified applications in the UE 1001. The identified application(s) in the UE 1001 may establish a PDU session to a specific data network name (DNN). The SMF 1024 may check whether the UE 1001 requests are compliant with user subscription information associated with the UE 1001. In this regard, the SMF 1024 may retrieve and / or request to receive update notifications on SMF 1024 level subscription data from the UDM 1027.

[0158] The SMF 1024 may include the following roaming functionality: handling local enforcement to apply QoS SLAB virtual Public Land Mobile Network (VPLMN); charging data collection and charging interface (VPLMN); lawful intercept (in VPLMN for SM events and interface to LI system); and support for interaction with external DN for transport of signaling for PDU session authorization / authentication by external DN. An N16 reference point between two SMFs 1024 may be included in the system 1000, which may be between another SMF 1024 in a visited network and the SMF 1024 in the home network in roaming scenarios. Additionally, the SMF 1024 may exhibit the Nsmf service-based interface.

[0159] The NEF 1023 may provide means for securely exposing the services and capabilities provided by 3GPP network functions for third party, internal exposure / re-exposure, Application Functions (e.g., AF 1028), edge computing or fog computing systems, etc. In such embodiments, the NEF 1023 mayauthenticate, authorize, and / or throttle the AFS. NEF 1023 may also translate information exchanged with the AF 1028 and information exchanged with internal network functions. For example, the NEF 1023 may translate between an AF- Service-ldentifier and an internal SCC information. NEF 1023 may also receive information from other network functions (NFs) based on exposed capabilities of other network functions. This information may be stored at the NEF 1023 as structured data, or at a data storage NF using standardized interfaces. The stored information can then be re-exposed by the NEF 1023 to other NFs and AFs, and / or used for other purposes such as analytics. Additionally, the NEF 1023 may exhibit an Nnef service-based interface.

[0160] The NRF 1025 may support service discovery functions, receive NF discovery requests from NF instances, and provide the information of the discovered NF instances to the NF instances. NRF 1025 also maintains information of available NF instances and their supported services. As used herein, the terms "instantiate," "instantiation," and the like may refer to the creation of an instance, and an "instance" may refer to a concrete occurrence of an object, which may occur, for example, during execution of program code. Additionally, the NRF 1025 may exhibit the Nnrf service-based interface.

[0161] The PCF 1026 may provide policy rules to control plane function(s) to enforce them and may also support unified policy framework to govern network behavior, The PCF 1026 may also implement a front end (FE) to access subscription information relevant for policy decisions in a UDR of the UDM 1027. The PCF 1026 may communicate with the AMF 1021 via an N15 reference point between the PCF 1026 and the AMF 1021 , which may include a PCF 1026 in a visited network and the AMF 1021 in case of roaming scenarios. The PCF 1026 may communicate with the AF 1028 via an NS reference point between the PCF 1026 and the AF 1028; and with the SMF 1024 via an N7 reference point between the PCF 1026 and the SMF 1024, The system 1000 and / or CN 1020 may also include an N24 reference point between the PCF 1026 (in the home network) and a PCF 1026 in a visited network, Additionally, the PCF 1026 may exhibit an Npcf service-based interface.

[0162] The UDM 1027 may handle subscription-related information to support the network entities' handling of communication sessions, and may store subscription data of UE 1001. For example, subscription data may be communicated between the UDM 1027 and the AMF 1021 via an NS reference point between the UDM 1027 and the AMF. The UDM 1027 may include two parts, an application FE and a UDR (the FE and UDR are not shown by FIG. 10). The UDR may store subscription data and policy data for the UDM 1027 and the PCF 1026, and / or structured data for exposure and application data (including PFDs for application detection, application request information for multiple UEs 1001 ) for the NEF 1023. The Nadr service-based interface may be exhibited by the UDR 221 to allow the UDM 1027, PCF 1026, and NEF 1023 to access a particular set of the stored data, as well as to read, update (e.g., add, modify), delete, and subscribe to notification of relevant data changes in the UDR. The UDM may include a UDM- FE, which is in charge of processing credentials, location management, subscription management and so on. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing, user identification handling, access authorization, registration / mobility management, and subscription management. The UDR may interact with the SMF 1024 via an NI0 reference point between the UDM 1027 and the SMF 1024. UDM 1027 may also support SMS management, wherein an SMS-FE implements the similar application logic as discussed previously. Additionally, the UDM 1027 may exhibit the Nudm service based interface.

[0163] The AF 1028 may provide application influence on traffic routing, provide access to the NCE, and interact with the policy framework for policy control. The NOE may be a mechanism that allows the CN 1020 and AF 1028 to provide information to each other via NEF 1023, which may be used for edge computing implementations. In such implementations, the network operator and third party services may be hosted close to the UE 1001 access point of attachment to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. For edge computing implementations, the 5GC may selecta UPF 1002 close to the UE 1001 and execute traffic steering from the UPF 1002 to DN 1003 via the N6 interface. This may be based on the UE subscription data, UE location, and information provided by the AF 1028. In this way, the AF 1028 may influence UPF (re)selection and traffic routing. Based on operator deployment, when AF 1028 is considered to be a trusted entity, the network operator may permit AF 1028 to interact directly with relevant NFs. Additionally, the AF 1028 may exhibit an Naf service-based interface.

[0164] The NSSF 1029 may select a set of network slice instances serving the UE 1001. The NSSF 1029 may also determine allowed Network Slice Selection Assistance Information (NSSAI) and the mapping to the subscribed single NSSAI (S-NSSAI) is, if needed. The NSSF 1029 may also determine the AMF set to be used to serve the UE 1001 , or a list of candidate AMF(s) 1021 based on a suitable configuration and possibly by querying the NRF 1025. The selection of a set of network slice instances for the UE 1001 may be triggered by the AMF 1021 with which the UE 1001 is registered by interacting with the NSSF 1029, which may lead to a change of AMF 1021. The NSSF 1029 may interact with the AMF 1021 via an N22 reference point between AMF 1021 and NSSF 1029; and may communicate with another NSSF 1029 in a visited network via an N31 reference point (not shown by FIG. 10). Additionally, the NSSF 1029 may exhibit an Nnssf service-based interface.

[0165] As discussed previously, the CN 1020 may include a short message service function (SMSF), which may be responsible for SMS subscription checking and verification, and relaying SM messages to / from the UE 1001 to / from other entities, such as an SMS-GMSG / IWMSC / SMS-router. The SMS may also interact with AMF 1021 and UDM 1027 for a notification procedure that the UE 1001 is available for SMS transfer (e.g., set a UE not reachable flag, and notifying UDM 1027 when UE 1001 is available for SMS).

[0166] The CN 1020 may also include other elements that are not shown by FIG. 10, such as a Data Storage system / architecture, a 5G-EIR, a Security Edge Protection Proxy (SEPP), and the like. The Data Storage system may include a Structured Data Storage Network Function (SDSF), air Unstructured Data StorageFunction (UDSF), and / or the like. Any network function (NF) may store and retrieve unstructured data into / from the UDSF (e.g., UE contexts), via N18 reference point between any NF and the UDSF (not shown by FIG. 10), Individual NFs may share a UDSF for storing their respective unstructured data or individual NFs may each have their own UDSF located at or near the individual NFs. Addition- ally, the UDSF may exhibit an Nudsf service-based interface (not shown by FIG. 10). The 5G-EIR may be an NF that checks the status of permanent equipment identifier (PEI) for determining whether particular equipment / entities are blacklisted from the network; and the SEPP may be a non-transparent proxy that performs topology hiding, message filtering, and policing on inter-PLMN control plane interfaces.

[0167] Additionally, there may be many more reference points and / or servicebased interfaces between the NF services in the NFs; however, these interfaces and reference points have been omitted from FIG. 10 for clarity. In one example, the CN 1020 may include an Nx interface, which is an inter-CN interface between a mobility management entity (MME) and the AMF 1021 in order to enable interworking between CN 1020 and a CN in a 4G system. Other example interfaces / reference points may include an N5G-EIR service-based interface exhibited by a 5G-EIR, an N27 reference point between the NRF in the visited network and the NRF in the home network; and an N31 reference point between the NSSF in the visited network and the NSSF in the home network.FIG. 1 1 : Core Network

[0168] FIG. 1 1 illustrates an example architecture of a system 1100 including a core network (CN) 1120 in accordance with various embodiments. The CN 1 120 may be a core network for a 4G Evolved Packet Core System (which may be referred to as an EPS or EUTRA). The system 1100 is shown to include a UE 1001 , which is described above; a (R)AN 11 10, which may be the same or similar to the BSs 102A or 102N described above; and a data network (DN) 1003, which is described above; and a CN 1120. The CN 1 120 may include a number of network functions including an Home Subscriber Server Function (HSS) 1 122; an MobilityManagement Entity Function (MME) 1121 which may be the same or similar to the MME 621 described above; a Serving Gateway Function (S-GW) 1124, which may be the same or similar to the S-GW 622 described above; a Policy and Charging Rules Function (PCRF) 1 104; and a Packet Data Network Gateway Function (PDN-GW) 1 102, which may be referred to as a P-GW and which may be the same or similar to the P-GW 623 described above. These network functions may be implemented, in some cases, as virtualized software-based functions / services.

[0169] The PDN-GW 1 102 may act as interconnect to DN 1003. A PDN connection is a logical connection between the UE and the DN. The PDN-GW 1 102 may also perform packet routing, packet filtering, and allocate an IP address to UEs. PDN-GW 1 102 may perform functions similar to those described above performed by SMF 1024 and UDP 1002. PCRF 1 104 may define quality policy rules and ensure the competent application of real-time charging for user data. PCRF 1 104 may perform functions similar to those described above performed by PCF 1026. PDN-GW 1102 and PCRF 1 104 may utilize an Gx interface to exchange data for policy enforcement and the like. S-GW 1124 may handle user data traffic and route incoming and outgoing IP packets. S-GW 1124 may perform functions similar to those described above performed by UDP 1002. The S-GW 1124 and the PDN-GW 1102 may utilize an S5 / S8a interface to exchange user plane data via a protocol stack, for example, as described above with respect to FIG. 9.

[0170] HSS 1 122 may serve as the primary database repository of subscriber information. HSS 1 122 may perform functions similar to those described above performed by UDM 1027 and AUSF 1022. HSS 1 122 and MME 1121 may utilize an S6a interface to exchange subscriber information. MME 1 121 may provide mobility session management and support subscriber authentication, roaming, and handovers to other networks. MME 1 121 may perform functions similar to those described above performed by AMF 1021 and SMF 1024. As illustrated in FIG. 10 and FIG. 1 1 , each of AMF 1021 and MME 1121 include an N26 reference point. An N26 reference point is an inter-CN interface between an AMF 1021 (FIG. 10) and an MME 1121 (FIG. 1 1 ) in order to enable interworking between a 5G core network 1020 and an EPC 1 120. Interworking procedures using N26 interfaceenable the exchange of mobility management (MM) and session management (SM) states between the source and target networks. Handover procedures are supported through N26 interface. 3GPP TS 23.501 V18.4.0 (2023-12) (hereinafter “3GPP TS 23.501 ”), describes interworking with the N26 interface.

[0171] As described above, a PDU session may refer to a PDU connectivity service that provides or enables the exchange of PDUs between a UE and a data network (DN) to be identified. 3GPP TS 23.501 , clause 5.6.9.2 provides that for PDU sessions established in the 5G system (5GS), 6G system (6GS), three Session and Service Continuity (SSC) modes are defined. The support of SSC mode 1 is mandatory and the support of SSC mode 2 and 3 are optional for a UE in the 5GS or 6GS. When SSC mode 1 is used, the UPF 1002 acting as PDU Session Anchor is maintained during the lifetime of the PDU Session. If the PDU session provides internet protocol (IP) connectivity, the IP address or IPv6 prefix associated with the PDU session remains the same during the lifetime of the PDU Session. When SSC mode 2 is used, the UPF acting as PDU Session Anchor may be changed by the network. This is initiated by the network in a "break before make" manner. That is, by sending a PDU SESSION RELEASE COMMAND message with the 5GSM cause #39 "reactivation requested," the network triggers the release of the current PDU Session and requests the UE to initiate the establishment of a new PDU session. If the PDU session provides IP connectivity, then with the release of the old UPF, the existing IP address or IPv6 prefix will be released. When SSC mode 3 is used, the UPF acting as PDU Session Anchor may be changed by the network in a "make before break" manner. Here the SMF1024 initiates a PDU session modification procedure to trigger a PDU session reactivation by including the 5GSM cause #39 "reactivation requested" in the PDU SESSION MODIFICATION COMMAND message. With this, the SMF requests the UE to initiate an additional UE-requested PDU session establishment procedure with the PDU parameters (PDU session type, SSC mode, DNN, S-NSSAI) which have been used for the existing PDU session. Once the second PDU session is established, the SMF can release the first PDU session. With the change of the UPF, a new IP address or IPv6 prefix is assigned to the UE.

[0172] While the term 5GSM is used throughout, it is not intended to be limiting. A 6G Session Management IE may also be used, such as a 6GSM UE capability, with specific 6GSM causes, or a 6GSM network feature support Information Element (IE).

[0173] The support of SSC mode 2 and 3 is not indicated to the network by an SM (Session Management) UE capability. Instead the UE indicates the requested SSC mode upon establishing a PDU session. If the UE supports SSC mode 2, it shall support the reactivation of a PDU session when receiving a PDU SESSION RELEASE COMMAND with 5GSM cause #39 "reactivation requested". If the UE supports SSC mode 3, it shall support the reactivation of a PDU session when receiving a PDU SESSION MODIFICATION COMMAND messages with 5GSM cause #39 "reactivation requested". Further, according to 3GPP TS 23.501 , clause 5.6.9.2, “a SSC mode associated with a PDU Session does not change during the lifetime of a PDU Session.”

[0174] On the other hand, for PDN connections in an EPC, the concept of SSC modes is not supported. According to 3GPP TS 23.502 V18.4.0 (2023-24) (hereinafter “3GPP TS 23.502”), clause 4.11.1.1 , which provides “Interworking between EPS and 5GS is supported with IP address preservation by assuming SSC mode 1 ,” interworking between the Evolved Packet System (EPS) and 5GS is therefore limited to SSC mode 1. There may be several issues caused by interworking between the Evolved Packet System (EPS) and 5GS being limited to SSC mode 1 .

[0175] For example, when interworking with an EPC occurs (e.g., the UE moves from 5GS to EPS), session continuity for PDU sessions established with SSC mode 2 or 3 is not supported. In the case of idle-mode mobility or PS handover from NG-RAN to E-UTRAN 'with support of the N26 interface', these PDU sessions are not transferred to EPS and converted into PDN connections by the network and the UE. Instead, after the inter-system change to EPS, for each of these sessions, the UE needs to initiate a new PDN connectivity request procedure to establish them again. This results in additional signaling and possibly in longer service interruption times.

[0176] Additionally, when the UE established a PDN connection in EPS and performs idle-mode mobility or PS handover from E-UTRAN to NG-RAN, the UE and the network will always convert the PDN connection into a PDU session with SSC mode 1 . If for some reason the SSC mode 2 or 3 would be better for a specific application, then the UE will need to release the existing PDU session and reestablish it with SSC mode 2 or 3, respectively. This results in additional signaling and possibly in longer service interruption times.

[0177] Further, in principle, similar issues exist also for the interworking between the 5GS and the EPS (i.e., 5GC connected to EPC) for mobility 'without support of the N26 interface', and for the interworking between the 5GS and non- 3GPP access connected to EPC. However, for these cases, the network does not support the "automatic" transfer of the PDU session to a PDN connection or to an IP session over non-3GPP access in 4G, or the transfer back to a PDU session in the 5GS. So, even for SSC mode 1 , the UE needs to initiate explicit signaling procedures to re-establish the IP connectivity via the new radio access (e.g., a PDN connectivity request procedure with request type "handover" in E-UTRAN, for example, as described in 3GPP TS 24.301 V18.5.0 (2023-12) (hereinafter “3GPP TS 24.301 ”); a PDU session establishment request procedure with request type "existing PDU session" in NG-RAN for example, as described in 3GPP TS 24.301 ; or some non-3GPP specific procedures to establish IP connectivity in a non-3GPP RAN, for example, as described in 3GPP TS 23.402 V18.3.0 (2023-12) (hereinafter “3GPP TS 23.402”)).

[0178] Thus, for various interworking scenarios, additional signaling between UE and network may be employed for session continuity for SSC mode 2 and 3. Further, it should be noted that when the UE needs to establish a new PDU session / PDN connection, then inside the network some DL user data packets may be lost that cannot be redirected from the old PDU session to the new PDN connection or vice versa.

[0179] As described above, the concept of SSC modes is not supported in EPC. Nevertheless, similar functionality as in the 5GS for SSC mode 1 and 2 exists. That is, similar to SSC mode 1 , the EPC may maintain the PDN-GW acting as sessionanchor and thus the IP address or IPv6 prefix, if any, during the lifetime of the PDN connection. Further, similar to SSC mode 2, the network can initiate a "break before make" re-establishment of a PDN connection by triggering an EPS bearer context deactivation with ESM cause #39 "reactivation requested" for the default EPS bearer context. The support of ESM cause #39 is mandatory for UEs. It should be noted that the EPC does not support a functionality comparable to SSC mode 3. Nevertheless, as in 5GS, it is the network's decision when to initiate the signaling for the change of the PDU Session Anchor. Thus, a PDU session for which SSC mode 3 is applied in 5GS is capable of be transferred to a PDN connection in an EPC and maintained without change of the session anchor (i.e., the PDN-GW) at least for a certain time (e.g., until the UE has moved too far away from the location where it performed inter-system change from 5GS to EPS).

[0180] It should be noted, however, that as provided above, 3GPP TS 23.502, clause 4.11.1.1 , states:"Interworking between EPS and 5GS is supported with IP address preservation by assuming SSC mode 1 ."And further states:"On mobility from EPS to 5GS, the UE sets the SSC mode of the mapped PDU Session to SSC mode 1 ."

[0181] Correspondingly, in 3GPP TS 24.501 , clause 6.1 .4.1 , it is specified that for inter-system change from EPS to 5GS with N26 interface, the UE shall set:'d) the SSC mode of the PDU session to "SSC mode 1";'And in clause 6.4.1 .2:"If the UE requests transfer of an existing PDN connection in the EPS to the 5GS or the UE requests transfer of an existing PDN connection in an untrusted non-3GPP access connected to the EPC to the 5GS, the UE shall set the SSC mode IE to "SSC mode 1"."

[0182] So, even if strictly speaking there is no explicit requirement in 3GPP TS23.501 , 23.502 and 24.501 to release a PDU session of SSC mode 2 or 3 upon inter-system change from 5GS to 4G (e.g. EPS), the UE will run into a problem when it returns to 5GS and attempts to convert the PDN connection back into a PDU session, because either:- it follows the above requirements and changes the SSC mode to 1 , thus violating the rule that the "SSC mode associated with a PDU Session does not change during the lifetime of a PDU Session", or- it needs to violate the above requirements and set the SSC mode of the PDU session to the value it had during the UE's previous stay in 5GS, i.e., 2 or 3, respectively.

[0183] Further, if originally the UE established the PDN connection in EPS, there may be issues when the session is transferred to 5GC, because when establishing the PDN session in EPS, the UE cannot indicate the requested SSC mode to be used. Furthermore, when the inter-system change to 5GS is with N26 interface support, then the network will automatically convert the PDN connections to PDU sessions, i.e., without explicit Session Management signaling,, so currently 3GPP TS 24.501 does not support the option for the UE to indicate its request for an SSC mode different from 1 .

[0184] As such, as described herein, mechanisms of the illustrated embodiments provide examples for allowing session continuity for inter-system changes between EPC and 5GC and vice-versa.FIGS. 12-20: Novel PDN connectivity and PDU session communication

[0185] According to some embodiments, signaling enhancements may be added to the PDN connectivity procedure in 4G (e.g. EPS) and to the PDU session modification procedure in 5G (e.g. 5GS) or 6GS to enable a UE 1001 and a network 1020 to negotiate an SSC mode 2 or 3 for a PDU session. Further, a support indication may be added to a SM capability IE, such a 5G or 6G SM, by which the UE 1001 can indicate to the network 1020 that it supports session continuity to EPS for PDU sessions established with SSC mode 2 or 3.

[0186] Referring now to FIG. 12, in an embodiment of the present disclosure, a diagram 1200 shows an example where if the PDN connection is to be established via EPC, a UE may indicate the SSC mode in the PDN session establishment. In FIG. 12, in order to allow a session continuity between EPC 1 120 and 5GC 1020 for PDN connections for which in 5GC SSC mode 2 or 3 should be used, the UE 1001 indicates the requested SSC mode in the Protocol configuration options (PCO) IE or the Extended protocol configuration options IE in a PDN CONNECTIVITY REQUEST. That is, according to the techniques here, new parameters may be added to a Protocol configuration options IE and an Extended protocol configuration options IE to indicate the requested SSC mode and the selected SSC mode. 3GPP TS 24.008 V18.5.0 (2023-12) (hereinafter “3GPP TS 24.008”) describes a Protocol configuration options IE and an Extended protocol configuration options IE. In one example, the SSC mode may be added to a Protocol configuration options IE. In one example, the SSC mode may be added to a Extended protocol configuration options IE.

[0187] Referring again to FIG. 12, if the network supports the requested SSC mode, it allocates SM parameters (e.g., PDU session ID, S-NSSAI) and includes the selected SSC mode in the Protocol configuration options IE (or the Extended protocol configuration options IE) in the ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message.

[0188] In one example, if the indicated SSC mode is not supported the network may reject the PDN CONNECTIVITY REQUEST with SM cause #68 "not supported SSC mode". In this case, the UE 1001 can then repeat the PDN CONNECTIVITY REQUEST including a different SSC mode in the Protocol configuration options IE or the Extended protocol configuration options IE (e.g., if SSC mode 2 is not supported, the UE 1001 may include SSC mode 1 in a repeated request). It should be noted that for this purpose SM cause #68 may be introduced in the EPC (3GPP TS 24.301 ). Further, in one example, if the indicated SSC mode is not supported, the network may accept the UE requested PDN connectivity without including the SSC mode in the Protocol configuration options IE or the Extended protocol configuration options IE in the ACTIVATE DEFAULT EPSBEARER CONTEXT REQUEST message. In this case, the UE 1001 shall assume that SSC mode 1 is selected for 5GC 1020. It should be noted that this reaction will also be the reaction of a legacy network implementation, which will ignore the requested SSC mode in the Protocol configuration options IE or the Extended protocol configuration options IE as an unknown parameter.

[0189] Referring again to FIG. 12, after the UE 1001 sends the ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPT message, the UE 1001 moves from the EPC 1 120 to the 5GC 1020 and a mobility registration update in the 5GC 1020 occurs. Further, the 5GC 1020 triggers reallocation of the UPF. That is, by sending a PDU SESSION RELEASE COMMAND message with the 5GSM cause #39 "reactivation requested", the 5GC 1020 triggers the release of the current PDU Session and requests the UE to initiate the establishment of a new PDU session and a new PDU session is established. As described above, if a UE supports SSC mode 2, it shall support the reactivation of a PDU session when receiving a PDU SESSION RELEASE COMMAND with 5GSM cause #39 "reactivation requested". That is, the UE 1001 sends a PDU SESSION RELEASE COMPLETE message and a PDU SESSION ESTABLISHMENT REQUEST message with the requested SSC mode (as previously requested and accepted in the PCO or the Extended PCO IE), and the 5GC 1120 sends a PDU SESSION ESTABLISHMENT ACCEPT message with the selected SSC mode. Accordingly, the PDU session is established between the UE 1001 and the 5GC 1120 in the requested SSC mode, such as SSC mode 1 , 2 or 3.

[0190] Referring now to FIG. 13, in an embodiment of the present disclosure, a diagram 1300 shows an example where if the PDN connection is to be established via an EPC 1 120, a UE 1001 may indicate the SSC mode with a PDU session modification procedure when entering the 5GC 1020. In FIG. 13, a PDN connection is established between the UE 1001 and the EPC 1120. That is, the UE 1001 sends a PDN CONNECTIVITY REQUEST, the PDN-GW 1102 of the EPC 1120 accepts the request to establish a PDN session and allocates the 5GSM parameters, the EPC 1120 sends an ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message with the 5GSM parameters, and the UE 1001 sends an ACTIVATEDEFAULT EPS BEARER CONTEXT ACCEPT message.

[0191] Referring again to FIG. 13, after the UE 1001 sends the ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPT message, the UE 1001 moves from the EPC 1120 to the 5GC 1020. In FIG. 13, in order to allow a session continuity between the EPC 1 120 and the 5GC 1020 for PDN connections for which 5GC SSC mode 2 or 3 should be used, the UE 1001 indicates the requested SSC mode in a PDU SESSION MODIFICATION REQUEST message and if the network supports the requested SSC mode, it includes the selected SSC mode in the PDU SESSION MODIFICATION ACCEPT message. That is, according to the techniques here, new parameters may be added to a PDU SESSION MODIFICATION REQUEST message and a PDU SESSION MODIFICATION ACCEPT message to indicate the requested SSC mode and the selected SSC mode. 3GPP TS 24.501 describes a PDU SESSION MODIFICATION REQUEST message and a PDU SESSION MODIFICATION ACCEPT message.

[0192] In one example, if the 5GC network 1020 supports the requested SSC mode, it shall include the Selected SSC mode IE in the PDU SESSION MODIFICATION ACCEPT message, which may be added to this message, according to the techniques herein. In one example, if the indicated SSC mode is not accepted by the 5GC 1020, it may reject the PDU session modification with an SM cause "#68 not supported SSC mode" and indicate the allowed SSC modes with an Allowed SSC mode IE. In this case, according to the techniques herein, an Allowed SSC mode IE may be added in a PDU SESSION MODIFICATION REJECT message. 3GPP TS 24.501 describes a PDU SESSION MODIFICATION REJECT message.

[0193] In one example, according to the techniques herein, the process for sending a PDU SESSION MODIFICATION REQUEST message may be based on the following:The SMF shall set the selected SSC mode IE of the PDU SESSION MODIFICATION COMMAND message to:a) the received SSC mode in the SSC mode IE included in the PDU SESSION MODIFICATION REQUEST message based on one or more of the PDU session type, the subscription and the SMF configuration; b) either the default SSC mode for the data network listed in the subscription or the SSC mode associated with the SMF configuration, if the SSC mode IE is not included in the PDU SESSION MODIFICATION REQUEST message.NOTE: For bullet b), to avoid issues for UEs not supporting all SSC modes, the network operator can, in the subscription data and local configuration, include at least SSC mode 1 in the allowed SSC modes, and set the default SSC mode to "SSC mode 1" as per 3GPP TS 23.501 .If the PDU session is an emergency PDU session, the SMF shall set the Selected SSC mode IE of the PDU SESSION MODIFICATION COMAND message to "SSC mode 1". If the PDU session is a non-emergency PDU session of "Ethernet" or "Unstructured" PDU session type, the SMF shall set the Selected SSC mode IE to "SSC mode 1" or "SSC mode 2". If the PDU session is a non-emergency PDU session of "IPv4", "IPv6" or "IPv4v6" PDU session type, the SMF shall set the selected SSC mode IE to "SSC mode 1", "SSC mode 2", or "SSC mode 3".

[0194] Referring again to FIG. 13, after sending the PDU SESSION MODIFICATION ACCEPT message, the 5GC 1020 triggers reallocation of the UPF. That is, by sending a PDU SESSION RELEASE COMMAND message with the 5GSM cause #39 "reactivation requested", the 5GC 1020 triggers the release of the current PDU Session and requests the UE 1001 to initiate the establishment of a new PDU session and a new PDU session is established with the selected SSC mode, for example as described above with respect to FIG. 12. Accordingly, the PDU session is established between the UE 1001 and the 5GC 1020 in the requested SSC mode.

[0195] As described in further detail below, according to the techniques herein, there may be cases where the PDN connection was originally established as aPDU session via 5GS, the network provided session continuity at the inter-system change from 5GC 1020 to EPC 1 120, and the UE 1001 did not perform any PDN connection re-establishment after the PDU session was transferred to the EPC 1120. In this case, the combined PDN-GW and SMF serving the PDN connection is still the same as at the time when the inter-system change from 5GC to EPC took place and the combined PDN-GW and SMF is still aware of the SSC mode with which the original PDU session was established. Therefore, when the above conditions are fulfilled and the UE performs inter-system mobility back from EPS to 5GS with N26 interface, the UE 1001 and the network 1020 only need to maintain the originally selected SSC mode. That is, there is no need to signal the SSC mode again. However, if the conditions are not fulfilled, because the UE 1001 performed a PDN connection re-establishment after the PDU session was transferred to the EPC 1 120, the UE 1001 can use the process illustrated in FIG 12. during the re-establishment of the PDN connection or the process illustrated in FIG. 13 when it performs the inter-system change to the 5GC 1020.

[0196] It should be noted that the UE 1001 indicating the selected SSC mode in the UE-requested PDU session modification performed after an inter-system change from S1 mode to N1 mode is similar to the indication of the support of multihomed IPv6 PDU session. Further, it should be noted that the number of bytes exchanged to indicate the requested and selected SSC mode parameter is similar for 1200 and 1300, but there can be cases where the UE 1001 would need to perform the PDU session modification in 1300 after the inter-system change from EPS to 5GS only for the purpose of signaling the requested SSC mode.

[0197] It should be noted that if a PDU session is established in a 5GC 1020 with SSC mode 2, a transfer to an EPC 1120 is, in principle, technically possible, as in the EPC 1 120, the support of the reject ESM cause #39 "reactivation requested" in the EPS bearer context deactivation is mandatory for the UE 1001. Further, if a PDU session is established in the 5GC 1020 with SSC mode 3, a transfer to the EPC 1120 is in principle technically possible, with the constraint that the Packet Data Network gateway (PDN-GW) 1 102 cannot be changed while the UE 1001 is operating in the EPC 1 120.

[0198] Although a transfer to the EPC 1120 is in principle possible, there may be UE 1001 implementations not supporting this functionality as it was described as not supported in the 3GPP standard up to Rel-18. For example, such a UE implementation could perform a local release of the respective PDU sessions when performing inter-system change to EPS. It should be noted, however, the SMF 1024 in the 5GS 1000 needs to perform certain resource reservations to be able to support session continuity to the EPS 1100. For example, during the establishment of the PDU session the SMF 1024 needs to exchange signaling with the AMF 1021 to get an EPS bearer ID assigned for the PDU session. Furthermore, the SMF 1024 needs to define a Mapped EPS bearer context for the PDU session and signal it to the UE in the PDU SESSION ESTABLISHMENT ACCEPT message together with the EPS bearer ID.

[0199] According to the techniques herein, in order to avoid a PDU session being lost at inter-system change to EPS 1 100, because a UE 1001 does not support session continuity, and to avoid that the SMF 1024 performs unnecessary resource reservations, a UE 1001 may indicate during the PDU session establishment, for example, in the 5GSM capability IE included in the PDU SESSION ESTABLISHMENT REQUEST message (or in the PDU SESSION MODIFICATION REQUEST message, as described above with respect to FIG. 13) whether it supports transfer of a PDU session with SSC mode 2 or 3 to the EPC. Further, a network receiving a PDU SESSION ESTABLISHMENT REQUEST message indicating whether it supports transfer of a PDU session with SSC mode 2 or 3 to the EPC may respond with a PDU SESSION ESTABLISHMENT REQUEST message including a 5GSM network feature support IEI indicating whether an inter-system change for SSC mode 2 or 3 are supported by the network.

[0200] A 5GSM capability IE is described in 3GPP TS 24.501 . FIG. 14 and FIG. 15 illustrate examples of a 5GSM capability IE enabling a UE to indicate whether it supports transfer of a PDU session with SSC mode 2 or 3 to the EPC, according to the techniques herein.

[0201] With respect to FIG. 14, in one example, bit values may be defined asfollows:RqoS (octet 3, bit 1) indicates the 5GSM capability to support reflective QoS, as follows:0 Reflective QoS not supported1 Reflective QoS supportedMulti-homed IPv6 PDU session (MH6-PDU) (octet 3, bit 2) indicates the 5GSM capability for Multi-homed IPv6 PDU session, as follows:0 Multi-homed IPv6 PDU session not supported1 Multi-homed IPv6 PDU session supportedSupported ATSSS steering functionalities and steering modes (ATSSS-ST) (octet 3, bits 4 to 7) indicates the 5GSM capability of ATSSS steering functionalities and steering modes, as follows:0 0 0 0 ATSSS not supported0 0 0 1 ATSSS Low-Layer functionality with any steering mode allowed for ATSSS-LL supported0 0 1 0 MPTCP functionality with any steering mode and ATSSS-LL functionality with only active-standby steering mode supported0 0 1 1 MPTCP functionality with any steering mode and ATSSS-LL functionality with any steering mode allowed for ATSSS-LL supported0 1 0 0 MPQUIC functionality with any steering mode and ATSSS-LL functionality with only active-standby steering mode supported0 1 0 1 MPQUIC functionality with any steering mode and ATSSS-LL functionality with any steering mode supported0 1 1 0 MPTCP functionality with any steering mode, MPQUIC functionality with any steering mode and ATSSS-LL functionality with only active-standby steering mode supported0 1 1 1 MPTCP functionality with any steering mode, MPQUIC functionality withany steering mode and ATSSS-LL functionality with any steering mode supportedAll other values are reserved.Transfer of port management information containers (TPMIC) (octet 3, bit 8)This bit indicates the 5GSM capability to support transfer of port management information containers, as follows:0 Transfer of port management information containers not supported1 Transfer of port management information containers supportedAccess performance measurements per QoS flow rule (APMQF) (octet 4, bitl ) indicates the 5GSM capability to support access performance measurements using the QoS flow of the non default QoS rule, that is used by the service data flow (SDF) traffic, as follows:0 Access performance measurements per QoS flow not supported.1 Access performance measurements per QoS flow supported.Secondary DN authentication and authorization over EPC (SDNAEPC) (octet4, bit 2) indicates the 5GSM capability to support secondary DN authentication and authorization over EPC, as follows:0 Secondary DN authentication and authorization over EPC not supported1 Secondary DN authentication and authorization over EPC supportedSSC support for inter-system change to EPC (SSC-EPC) (octet 4, bit 3) indicates the 5GSM capability to perform inter-system change to EPC for a PDU session associated with SSC mode 2 or 30 Inter-system change for SSC mode 2 or 3 not supported1 Inter-system change for SSC mode 2 or 3 supportedAll other bits in octet 4 to 15 are spare and shall be coded as zero, if the respective octet is included in the information element.

[0202] As illustrated in FIG. 14 and described above, a single bit (e.g., octet 4bit 3) is used to indicate support for SSC mode 2 or 3, i.e. , whichever is applicable for the PDU session for which the signaling is sent.

[0203] FIG. 15 illustrates an example where 2 bits are used in a 5GSM capability IE enabling a UE to indicate the support for SSC mode 2 and mode 3 separately. With respect to FIG. 15, in one example, bit values may be defined as provided above with respect to FIG. 14 with octet 4, bit 3 and octet 4, bit 4 defined as follows:SSC mode 2 support for inter-system change to EPC (SSC-EPC) (octet 4, bit3) indicates the 5GSM capability to perform inter-system change to EPC for a PDU session associated with SSC mode 20 Inter-system change for SSC mode 2 not supported1 Inter-system change for SSC mode 2 supportedSSC mode 3 support for inter-system change to EPC (SSC-EPC) (octet 4, bit4) indicates the 5GSM capability to perform inter-system change to EPC for a PDU session associated with SSC mode 30 Inter-system change for SSC mode 3 not supported1 Inter-system change for SSC mode 3 supported

[0204] A 5GSM network feature support IEI is described in 3GPP TS 24.501 . FIG. 16 illustrate examples of a 5GSM network feature support IEI enabling a network to indicate whether it supports transfer of a PDU session with SSC mode2 or 3 to the EPC 1 120. With respect to FIG. 16, in one example, bit values may be defined as follows:Ethernet PDN type in S1 mode (IEPT-S1) (octet 3, bit 1)This bit indicates network's capability for Ethernet PDN type in S1 mode, as follows:0 Ethernet PDN type in S1 mode not supported1 Ethernet PDN type in S1 mode supportedNon-3GPP access path switching (NAPS) (octet 3, bit 2)This bit indicates whether non-3GPP access path switching is supported, as follows:0 non-3GPP access path switching not supported1 non-3GPP access path switching supportedSSC support for inter-system change to EPC (SSC-EPC) (octet 3, bit 3)This bit indicates the network's capability to perform inter-system change to EPC for a PDU session associated with SSC mode 2 or 3, as follows:0 Inter-system change for SSC mode 2 or 3 not supported1 Inter-system change for SSC mode 2 or 3 supportedAll other bits in octet 3 to 15 are spare and shall be coded as zero, if the respective octet is included in the information element.

[0205] In one example, according to the techniques herein, when an SMF (e.g., SMF 1024) receives a PDU SESSION ESTABLISHMENT REQUEST message and, based on the SSC mode requested by the UE and on subscription data of the user, the SMF determines whether the SSC mode of the PDU session is 2 or 3. Then the SMF may check whether inter-system change for SSC mode 2 or 3 is supported. For example, as indicated in the example 5GSM capability IEI in FIG. 14 or FIG. 15. If both the UE and the network support inter-system change to EPS for a PDU session associated with SSC mode 2 or 3, the SMF may prepare for a possible later inter-system change to E-UTRAN 11 10 connected to EPC 1 120 "with support of N26 interface". That is, the SMF may trigger the allocation of an EPS bearer ID as specified in 3GPP TS 23.502, clause 4.1 1.1.4, and signal this EPS bearer ID together with some quality of service (QoS) related parameters in the Mapped EPS bearer contexts IE included in the PDU SESSION ESTABLISHMENT ACCEPT message to the UE. It should be noted that from the presence of the Mapped EPS bearer contexts IE in the PDU SESSION ESTABLISHMENT ACCEPT message, the UE can determine that the network is supporting session continuity to EPS for the respective PDU session with SSC mode 2 or 3. In oneexample, the SMF may indicate its support of session continuity in the 5GSM network feature support IE included in the response message PDU SESSION ESTABLISHMENT ACCEPT. For example, as described above, and as indicated in the example 5GSM network feature support IEI in FIG. 16. If both UE and network support inter-system change to EPS for a PDU session associated with SSC mode 2 or 3, the UE and the SMF memorize the selected SSC mode when the UE performs inter-system mobility from 5GS to EPC to use it again when later the UE reverts to 5GS.

[0206] Referring now to FIG. 17, in an embodiment of the present disclosure, a diagram 1700 shows an example where a PDU session is established via a 5GS 1000 and a UE 1001 indicates support for an inter-system change to an EPS 1 100 for a PDU session associated with SSC mode 2 or 3. In FIG. 17, a PDU session is established between the UE and the 5GS. That is, UE 1001 sends a PDU SESSION ESTABLISHMENT REQUEST message with a requested SSC mode and an indication whether support for an inter-system change to EPS for a PDU session associated with SSC mode 2 or 3 is supported, for example as described above. The SMF 1024 of the 5GC 1020 allocates EPS-SM parameters and checks whether the UE 1001 has indicated that inter-system change for SSC mode 2 or 3 is supported. In response to determining that the UE 1001 has indicated that intersystem change for SSC mode 2 or 3 is supported, the SMF 1024 may indicate its support of session continuity in the 5GSM network feature support IE included in the response message PDU SESSION ESTABLISHMENT ACCEPT, as described above.

[0207] As illustrated in FIG. 17, after PDU session establishment, the UE 1 101 moves from a 5GC 1020 to an EPC 1 120 and a PDU session with SSC mode 2 or 3 is handed over or converted into a PDN connection. That is, the PDN connection was originally established as a PDU session via 5GS, the network provided session continuity at the inter-system change from 5GS to EPC, and the UE did not perform any PDN connection re-establishment after the PDU session was transferred to EPC. In this case, the combined PDN-GW 1102 and SMF 1024 serving the PDN connection is still the same as at the time when the inter-system change from 5GS1000 to EPS 1 100 took place and the combined PDN-GW and SMF is still aware of the SSC mode with which the original PDU session was established. Therefore, when the UE 1001 performs an inter-system mobility back from the EPS 1100 to the 5GS 1000 with an N26 interface, the UE 1001 and the network only need to maintain the originally selected SSC mode. That is, there is no need to signal the SSC mode again. This can result in shorter service interruption times.

[0208] Referring now to FIG. 18, in an embodiment of the present disclosure, a diagram 1800 shows an example where a PDU session is established via 5GS 1000 and a UE 1001 indicates support for an inter-system change to EPS 1100 for a PDU session associated with SSC mode 2 or 3. In FIG. 18, similar to the example FIG. 17, a PDU session is established between the UE 1001 and the 5GS and after PDU session establishment, the UE 1001 moves from a 5GC 1020 to an EPC 1120. In the example, in FIG. 18 there is no re-establishment of the PDN connection in the EPC 1 120 and the UE 1001 moves from the EPC 1120 to the 5GC 1020. As there is no re-establishment of the PDN connection, the SSC mode is still know in the combined SMF 1024 and PDN-GW 1 102. As such, in this case, the UE 1001 can skip indicating the SSC mode to the 5GC 1020, upon the moving back to the 5GC 1020.

[0209] Referring now to FIG. 19, in an embodiment of the present disclosure, a diagram 1900 shows an example where a PDU session is established via 5GS1000 and UE 1001 indicates support for an inter-system change to EPS 1 100 for a PDU session associated with SSC mode 2 or 3. In FIG. 19, similar to the example in FIG. 17 and FIG. 18, a PDU session is established between the UE 1000 and the 5GS 1001 and after PDU session establishment, the UE moves from a 5GC 1020 to a EPC 1 120. Further, in FIG. 19, the EPC 1020 initiates a "break before make" re-establishment of a PDN connection by triggering an EPS bearer context deactivation with ESM cause #39 "reactivation requested" for the default EPS bearer context in a DEACTIVATE EPS BEARER CONTEXT REQUEST. The UE1001 accepts DEACTIVATE EPS BEARER CONTEXT REQUEST and establishes a PDN connection. That is, in a manner similar to that described with respect to the example illustrated in FIG. 12. It should be noted that because re-establishment ofthe PDN connection in EPC 1 120 happens, the UE 1001 is configured to indicate the requested SSC mode again. Further, in another example, the UE 1001 may indicate the requested SSC mode according to the example illustrated in FIG. 13. Finally, in FIG. 19, the UE 1001 may move from the EPC 1 120 back to the 5GC 1020, for example, as described above.FIG. 20: Flow Chart for a Method for establishing a Packet Data Unit (PDU) session

[0210] FIG. 20 illustrates a flow chart of establishing a Packet Data Unit (PDU) session, according to some embodiments. The method shown in FIG. 20 may be used in conjunction with any of the systems, methods, or devices illustrated in the Figures, among other devices. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Additional method elements may also be performed as desired.

[0211] In accordance with an embodiment, a method 2000 may transmit a PDU session establishment request including an indication in a 5GSM capability information element that an inter-system change for a SSC mode 2 or 3 is supported by the UE, as in block 2010. That is, for example, as described above, a UE may transmit a 5GSM capability information element including one or more bits indicating whether inter-system change for SSC mode 2 or 3 is supported.

[0212] In accordance with an embodiment method 2000 may receive a PDU session establishment accept request including an indication that an inter-system change for a SSC mode 2 or 3 is supported in a 5GSM network feature support information element, as in block 2020. That is, for example, as described above, a UE may receive a 5GSM network feature support information element including a bit indicating whether inter-system change for SSC mode 2 or 3 is supported.

[0213] In some embodiments, the indication in the 5GSM capability information element includes one bit having a value indicating whether SSC mode 2 or SSC mode 3 are supported.

[0214] In some embodiments, the one bit is located at a third bit of a fourth octet of the 5GSM capability information element.

[0215] In some embodiments, the indication in the 5GSM capability information element includes a first bit having a value indicating whether SSC mode 2 is supported and a second bit having a value indicating whether SSC mode 3 is supported.

[0216] In some embodiments, the first bit is located at a third bit of a fourth octet of the 5GSM capability information element and wherein the second bit is located at a fourth bit of the fourth octet.

[0217] In some embodiments, the indication in the 5GSM network feature support information element is located at a third bit of a third octet of the 5GSM network feature support information element.

[0218] In some embodiments, an apparatus is disclosed that is configured to cause a user equipment (UE) to perform any of the operations of the method 2000.

[0219] In some embodiments, an apparatus is disclosed that is configured to cause a base station to perform any of the operations of the method 2000.

[0220] In some embodiments, an apparatus is disclosed that is configured to cause a user equipment (UE) to perform any of the operations of the method 2000 and / or method 2000.

[0221] In some embodiments, a UE may be configured to transmit a PDN connectivity request including a requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network and receive an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is accepted in a Protocol configuration options (PCO).

[0222] In some embodiments, a UE may be configured to transmit a PDN connectivity request including a first requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network, receive an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is not supported in a Protocol configuration options (PCO), for example, by not including the SSC mode in the PCO, and transmit a PDNconnectivity request including a second requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network.

[0223] In some embodiments, a UE may be configured to transmit a PDU session modification request including a requested Session and Service Continuity (SSC) mode to a 5G core network and receive a PDU session modification accept indicating that the requested SSC mode is accepted.

[0224] Embodiments of the present disclosure may be realized in any of various forms. For example, some embodiments may be realized as a computer- implemented method, a computer readable memory medium, or a computer system. Other embodiments may be realized using one or more custom-designed hardware devices such as ASICs. Still other embodiments may be realized using one or more programmable hardware elements such as FPGAs.

[0225] In some embodiments, a non-transitory computer-readable memory medium may be configured so that it stores program instructions and / or data, where the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of the method embodiments described herein, or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets.

[0226] In some embodiments, a device (e.g., a UE 106) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets). The device may be realized in any of various forms.

[0227] Any of the methods described herein for operating a user equipment (UE)may be the basis of a corresponding method for operating a base station, by interpreting each message / signal X received by the UE in the downlink as message / signal X transmitted by the base station, and each message / signal Y transmitted in the uplink by the UE as a message / signal Y received by the base station.

[0228] Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

CLAIMSWhat is claimed is:1 . A method of establishing a Packet Data Unit (PDU) session by a user equipment (UE), the method comprising: transmitting a PDU session establishment request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a UE Session management capability information element; and receiving a PDU session establishment accept request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a Session management network feature support information element.

2. The method of claim 1 , wherein the indication in the UE Session management capability information element includes one bit having a value indicating whether an inter-system change for SSC mode 2 or SSC mode 3 is supported.

3. The method of claim 1 , wherein the indication in the UE Session management capability information element includes a first bit having a value indicating whether an inter-system change for SSC mode 2 is supported and a second bit having a value indicating whether an inter-system change for SSC mode 3 is supported.

4. The method of claim 1 , wherein the indication in the Session management network feature support information element is located at a third bit of a third octet of the Session management network feature support information element.

5. The method of claim 1 , wherein the UE Session management capability information element includes a 5GSM capability information element or a 6GSMcapability information element.

6. The method of claim 1 , wherein the Session management network feature support information element includes a 5GSM network feature support information element or a 6GSM network feature support information element.

7. A method of establishing a Packet Data Network (PDN) connection by a user equipment (UE), the method comprising: transmitting a PDN connectivity request including a requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network; and receiving an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is accepted in a Protocol configuration options (PCO).

8. A method of establishing a Packet Data Network (PDN) connection by a user equipment (UE), the method comprising: transmitting a PDN connectivity request including a first requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network; receiving an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is not accepted in a Protocol configuration options (PCO); and transmitting a PDN connectivity request including a second requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element to an evolved packet core (EPC) network.

9. A method of establishing a Packet Data Unit (PDU) session by a user equipment (UE), the method comprising: transmitting a PDU session modification request including a requestedSession and Service Continuity (SSC) mode to a core network; and receiving a PDU session modification accept indicating that the requestedSSC mode is accepted.

10. A method of establishing a Packet Data Unit (PDU) session, the method comprising: receiving a PDU session establishment request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a UE Session management capability information element; and transmitting a PDU session establishment accept request including an indication that an inter-system change for a Session and Service Continuity (SSC) mode 2 or 3 is supported in a Session management network feature support information element.

11. A method of establishing a Packet Data Network (PDN) connection, the method comprising: receiving a PDN connectivity request including a requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element; and transmitting an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is accepted in a Protocol configuration options (PCO).

12. A method of establishing a Packet Data Network (PDN) connection, the method comprising: receiving a PDN connectivity request including a first requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element; transmitting an activate default evolved packet core system (EPS) bearer context request including an indication that the requested SSC mode is not accepted in a Protocol configuration options (PCO); and receiving a PDN connectivity request including a second requested Session and Service Continuity (SSC) mode in a Protocol configuration options (PCO) information element.

13. A method of establishing a Packet Data Unit (PDU) session, the method comprising: receiving a PDU session modification request including a requestedSession and Service Continuity (SSC) mode; and transmitting a PDU session modification accept indicating that the requested SSC mode is accepted.

14. A user equipment (UE) comprising: one or more processors, coupled to a memory, configured to perform one or more of the methods of claims 1 to 13.

15. A device comprising: one or more processors, coupled to a memory, configured to perform one or more of the methods of claims 1 to 13.

16. A baseband processor configured to perform one or more of the method claims 1 to 13.

17. A baseband processor configured to cause a user equipment (UE) to perform one or more of the method claims 1 to 13.

18. A user equipment (UE) configured to perform any of the operations described herein.

19. A base station configured to perform any of the operations described herein.

20. A computer program product, comprising computer instructions which, when executed by one or more processors, perform any of the operations described herein.

Images