Method and system for camping a ue in 4g and 5g overlapping areas

Abstract

Various embodiments herein disclose a method of camping a user equipment (UE) on a cell, the method comprising: creating a combined most recently used (MRU) list by merging a list of 4G MRU frequencies with a public land mobile network (PLMN) having a 5GC and a list of 5G MRU frequencies; determining whether one of a 4G cell and a 5G cell with a 5G core (5GC) is available for camping by performing a MRU scan on the combined MRU list; performing at least one of the following: camping on one of the 4G cell with a 5G core and the 5G cell in response to determining that one of the 5G cell and the 4G cell with a 5G core is available, and performing a 4G MRU frequency scan on a list of 4G MRU frequencies without a 5GC in response to determining that one of the 4G cell with a 5G core and the 5G cell is not available.

Description

Technical Field

[0001] This disclosure relates to camping a user equipment (UE) on a cell when the UE is located in an overlapping area of ​​5G Standalone (SA), 5G Non-Standalone (NSA), and Long Term Evolution (LTE). For example, this disclosure relates to a method and system for rapid camping in an overlapping area of ​​4G and 5G. Background Technology

[0002] User equipment (UE) can exist in the overlapping area of ​​5G and 4G, where in non-standalone (NSA) devices, LTE cells can connect to the 5G core (5GC), which can be referred to as architecture option 7 according to the 3GPP connectivity standard. For 5G standalone (SA) networking, the gNodeB (gNB) connects directly to the 5GC network, which can be referred to as architecture option 2 according to the 3GPP connectivity standard. Summary of the Invention

[0003] Technical issues

[0004] When the UE is powered on, or when the UE is recovering from Out of Service (OOS), or when a higher priority scan is triggered, the device needs a long time to camp on the best available cell because there is a delay in finding a cell to camp on.

[0005] Figure 1 This illustrates the standard method for a UE to camp on a cell when it is in a power-on state or out-of-service (OOS) recovery state. For example... Figure 1 At point 102, the UE is powered on or recovering from OOS mode. At point 104, the 5G MRU (most recently used) frequency is being scanned to find a cell. At point 106, the method includes determining whether a cell has been found. At point 108, if a 5G cell is found, the UE camps on the 5G cell. At point 110, if no cell is found, the method includes performing a scan on the 4G MRU frequency. At point 112, the method includes determining whether a cell for camping the UE has been found after scanning the 4G MRU frequency. If a cell is found, the UE camps on a 4G cell with 5GC at point 114. If no cell is found at point 112, a 5G full-band scan is performed at point 116, and then if no cell is found at point 118 after performing the 5G full-band scan, a 4G full-band scan is performed at point 120.

[0006] As mentioned above, scanning the entire 5G frequency band and then scanning the entire 4G frequency band if no cells are found will cause delays and increase latency.

[0007] Figure 2 This illustrates a common method for keeping the UE hosted when it is in connected mode. For example... Figure 2 As shown, at 202, the UE connects to 5G. At 204, a higher-priority PLMN (Public Land Mobile Network) search is performed. At 206, the method includes determining whether the UE is connected in 5G mode. At 210, if the UE is connected to the 5G stack, a 5G full-band scan is performed in the background, followed by a 4G MRU scan and a 4G full-band scan at 212. If the UE is not connected to 5G, a 5G full-band scan is performed in the foreground at 208, followed by a 4G MRU scan and a 4G full-band scan at 214. At 216, the PLMN is reported to the upper layer. This results in a delay in reporting the PLMN to the upper layer.

[0008] Therefore, it is necessary to address the aforementioned drawbacks or other shortcomings, or at least provide useful alternatives.

[0009] Embodiments of this disclosure provide a method and system for enabling a UE to camp on a cell in a 5G and 4G overlap area without delay.

[0010] Embodiments of this disclosure improve the latency of searching for and reporting higher-priority PLMNs to higher layers during higher-priority PLMN searches.

[0011] Embodiments of this disclosure provide a method and system for keeping a UE in an optimal availability state when the UE is powered on or recovering from OOS mode.

[0012] Embodiments of this disclosure prepare a combined MRU list for reducing cell location latency.

[0013] The embodiments of this disclosure perform 5G scanning in parallel with 4G scanning.

[0014] Embodiments of this disclosure utilize transceiver groups available in 5G-enabled UEs to reduce UE dwell time.

[0015] Embodiments of this disclosure optimize the storage of frequency information for eLTE and 5G cells connected to the 5G core network.

[0016] Solution to the problem

[0017] This document discloses an example embodiment of a method for camping a user equipment (UE) on a cell when the UE is located in an overlapping area of ​​5G Standalone (SA), 5G Non-Standalone (NSA), and Long Term Evolution (LTE). The method includes: creating a combined MRU list by merging a list of 4G Most Recently Used (MRU) frequencies with a Public Land Mobile Network (PLMN) having a 5G core and a list of 5G MRU frequencies; and performing an MRU scan on the combined MRU list to determine whether one of a 4G cell with a 5G core and a 5G cell is available for camping the UE.

[0018] In an example embodiment, performing an MRU scan includes performing a scan of the list of 5G MRU frequencies in parallel with a scan of the list of 4G MRU frequencies with 5GC.

[0019] In an example embodiment, in response to an MRU scan based on a combined MRU list to determine that one of a 5G cell and a 4G cell with a 5G core is available for UE camping, the UE camps on one of the 4G cell with a 5G core and the 5G cell.

[0020] In an example embodiment, in response to determining that either a 4G cell with a 5G core or a 5G cell cannot be used for UE camping based on an MRU scan of the combined MRU list, the UE performs a 4G MRU frequency scan on the list of 4G MRU frequencies without a 5G core, and camps the UE based on the 4G MRU frequency scan.

[0021] In the example embodiment, the UE determines whether an SIB24 message providing details about the NR radio exists. Based on the presence of NR information, the UE searches for neighboring 5G cells for camping. If NR information does not exist, the UE camps on a 4G cell that does not have a 5G GC.

[0022] In an example embodiment, camping a UE based on a 4G MRU frequency scan includes performing a 4G MRU frequency scan on a list of 4G MRU frequencies that do not have a 5GC to determine whether a 4G cell without a 5GC is available for UE camping. Camping based on a 4G MRU scan includes camping the UE on a 4G cell without a 5GC in response to determining that a 4G cell without a 5GC is available for UE camping based on a 4G MRU frequency scan on a list of 4G MRU frequencies that do not have a 5GC. In an example embodiment, the UE performs a 5G full-band scan of the list of 5G frequencies and a 4G full-band scan of the list of 4G frequencies in parallel, and camps the UE based on either the 5G full-band scan or the 4G full-band scan.

[0023] In an example embodiment, camping a UE based on either a 5G full-band scan or a 4G full-band scan includes: determining whether a 4G cell is available based on a 4G full-band scan of a list of 4G frequencies, or determining whether a 5G cell is available based on a 5G full-band scan of a list of 5G frequencies, or determining whether both 4G and 5G cells are available. In an example embodiment, the UE camps on a 4G cell, and in response to determining that a 4G cell is available based on a 4G full-band scan, terminates the 5G full-band scan. When camping a UE on a 4G cell, 4G cells with a 5G core are given higher priority than 4G cells without a 5G core.

[0024] In the example embodiment, the UE camps on a 5G cell and terminates the 4G full-band scanning in response to determining that the 5G cell is available based on the 5G full-band scanning. In the example embodiment, in response to determining that the 5G cell is available based on the 5G full-band scanning and that the 4G cell is available based on the 4G full-band scanning, the UE camps on the 5G cell and terminates the 4G full-band scanning.

[0025] In the example embodiment, based on the UE camping on a 4G cell without a 5GC, the UE determines whether an SIB24 message providing details about the NR radio exists. If the NR information exists, the UE searches for neighboring 5G cells to camp on. If the NR information does not exist, the UE camps on a 4G cell without a 5GC.

[0026] Therefore, various embodiments herein disclose a method for keeping a UE camped on a cell based on the UE being in a connected state. The method includes: when the UE is in connected mode, the UE detects a higher-priority PLMN scan and determines whether an Rx chain is available; in response to detecting an available Rx chain, the UE performs a 5G full-band scan of a list of 5G frequencies and a 4G full-band scan of a list of 4G frequencies in parallel; and camps the UE based on either the 5G full-band scan or the 4G full-band scan.

[0027] In an example embodiment, UE camping based on 5G full-band scanning or 4G full-band scanning includes: determining whether a 4G cell is available based on a 4G full-band scan of a list of 4G GMRU frequencies, or based on a 5G full-band scan of a list of 4G GMRU frequencies. The 5G full-band scan of the MRU frequency list determines whether a 5G cell is available, or whether both 4G and 5G cells are available; and in response to determining that a 4G cell is available based on the 4G full-band scan: the UE is camped on the 4G cell, the 5G full-band scan is terminated, and the scanned cell list obtained based on the 4G full-band scan is reported; or in response to determining that a 5G cell is available based on the 5G full-band scan: the UE is camped on the 5G cell, the 4G full-band scan is terminated, and the scanned cell list obtained based on the 5G full-band scan is reported; or in response to determining that a 5G cell is available based on both the 5G full-band scan and the 4G full-band scan: the UE is camped on the 5G cell, the 4G full-band scan is terminated, and the scanned cell list obtained based on the 4G full-band scan and the scanned cell list obtained based on the 5G full-band scan are reported. In the example embodiment, a 4G cell with 5GC is preferred over a 4G cell without 5GC.

[0028] In an example embodiment, the UE performing a 5G full-band scan of the 5G frequency list and a 4G full-band scan of the 5G frequency list in parallel includes: the UE detecting whether the UE is in 5G connection mode; and in response to determining that the UE is in 5G connection mode, triggering a background 5G full-band scan of the 5G frequency list and a foreground 4G full-band scan of the 4G frequency list, or in response to determining that the UE is not in 5G connection mode, triggering a foreground 5G full-band scan of the 5G frequency list and a 4G full-band scan of the 5G frequency list.

[0029] Therefore, various embodiments herein disclose methods for camping a UE on a cell based on the UE's presence in an overlapping area of ​​5G Standalone (SA), 5G Non-Standalone (NSA), and Long Term Evolution (LTE) networks. The UE includes a memory and a processor coupled to a communicator including communication circuitry. The UE is configured to: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] The MRU frequency lists are merged to create a combined MRU list; an MRU scan is performed on the combined MRU list to determine whether one of a 4G cell with a 5G core and a 5G cell can be used to camp the UE; in response to determining that one of a 5G cell and a 4G cell with a 5G core can be used to camp the UE based on the MRU scan of the combined MRU list, the UE is camped on one of the 4G cell with a 5G core and the 5G cell; or in response to determining that one of a 4G cell with a 5G core and a 5G cell cannot be used to camp the UE based on the MRU scan of the combined MRU list, a 4G MRU frequency scan is performed on the list of 4G MRU frequencies without 5GC, and the UE is camped based on the 4G MRU frequency scan.

[0030] These and other aspects of the various exemplary embodiments herein will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. However, it should be understood that the following description is given as illustrative rather than limiting, although it indicates various exemplary embodiments and their many specific details. Many changes and modifications can be made within the scope of the various exemplary embodiments herein without departing from their true spirit, and the embodiments herein include all such modifications. Attached Figure Description

[0031] The above and other aspects, features, and advantages of certain embodiments of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0032] Figure 1 This is a flowchart illustrating a conventional method for retaining a UE when it exists in an overlapping area of ​​5G and 4G, according to existing technology;

[0033] Figure 2 This is a flowchart illustrating a conventional method for searching for and reporting the PLMN to the upper layer when the UE is in connected mode, according to the prior art;

[0034] Figure 3A This is a block diagram illustrating example configurations of a UE for a camped cell according to various embodiments;

[0035] Figure 3B This is a block diagram illustrating various components of a cell selector for a UE according to various embodiments;

[0036] Figure 4 This is a diagram illustrating example dwell times of a UE based on a combined MRU scan according to various embodiments;

[0037] Figure 5 This is a diagram illustrating example new interfaces between 5G NAS and 4G according to various embodiments;

[0038] Figure 6 This is a flowchart illustrating example methods for residing a UE when it is present in an overlapping area of ​​4G and 5G, according to various embodiments;

[0039] Figure 7 This is a flowchart illustrating example methods for reporting higher-order PLMNs to upper layers when the UE is in connected mode, according to various embodiments;

[0040] Figure 8 This is a signal flow diagram illustrating example sequences for camping a UE when the UE is present in a 4G and 5G overlap area according to various embodiments;

[0041] Figure 9 This is a signal flow diagram illustrating example sequences for reporting higher-order PLMNs to upper layers when the UE is in connected mode, according to various embodiments; and

[0042] Figure 10A , 10B Figures 1 and 10C are illustrations of example implementations and example methods of the prior art according to various embodiments. Detailed Implementation

[0043] The various exemplary embodiments disclosed herein, along with their various features and advantageous details, are explained with reference to the non-limiting exemplary embodiments illustrated in the accompanying drawings and described in the following disclosure. Descriptions of well-known components and processing techniques may be omitted to avoid unnecessarily obscuring the embodiments herein. The various exemplary embodiments disclosed herein are not necessarily mutually exclusive, as some embodiments may be combined with one or more other embodiments to form new embodiments. The term "or" as used herein means non-exclusive, or unless otherwise specified. The examples used herein are merely to facilitate understanding of how the embodiments herein can be practiced, and further to enable those skilled in the art to practice the various exemplary embodiments herein. Therefore, these examples should not be construed as limiting the scope of the embodiments herein.

[0044] As is conventional in the art, embodiments can be described and illustrated based on blocks that perform one or more described functions. These blocks, referred to herein as managers, units, modules, hardware components, etc., are physically implemented by analog and / or digital circuitry (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuitry, etc.) and may optionally be driven by firmware. The circuitry may be embodied, for example, in one or more semiconductor chips or on a substrate support such as a printed circuit board. The circuitry of a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmable microprocessors and associated circuitry), or by a combination of dedicated hardware for performing some functions of the block and a processor for performing other functions of the block. Without departing from the scope of this disclosure, each block of an embodiment may be physically divided into two or more interacting discrete blocks. Similarly, without departing from the scope of this disclosure, the blocks of an embodiment may be physically combined into more complex blocks.

[0045] The accompanying drawings are provided to aid in understanding the various technical features, and it should be understood that the various exemplary embodiments presented herein are not limited to the drawings. Therefore, this disclosure should be construed as extending to any changes, equivalents, and substitutions other than those specifically listed in the drawings. While the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another.

[0046] The various example embodiments disclosed herein provide a method and system for improving latency when a UE is camped in an area where 4G and 5G overlap. Unlike conventional techniques, in these example embodiments, the combined MRU list is created by an MRU list creator by merging 5G MRU frequencies with 4G MRU frequencies having a PLMN supported by a 5G core (5GC). A cell selector scans the combined MRU list to find a cell for camping the UE. If the UE is still not camped, the cell selector performs a 5G full-band scan using the UE's first transceiver and a 4G full-band scan in parallel using the UE's other transceiver.

[0047] Therefore, scanning the combined MRU list and / or performing parallel 5G full-band scanning and 4G full-band scanning helps reduce the latency of the UE, thereby enabling fast UE dwell.

[0048] Unlike conventional technologies, the example embodiments exhibit less latency when camped in a cell, whether resuming from OOS mode, when powered on, or when in connected mode. Various embodiments also reduce latency when reporting higher-order PLMNs.

[0049] Now refer to the attached diagram, and more specifically to... Figure 3A , 3B , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 9 In all the accompanying drawings, similar reference numerals always denote corresponding features, illustrating various exemplary embodiments.

[0050] Figure 3A This is a block diagram illustrating an example UE 300, where, according to various embodiments, UE 300 exists in a 5G and 4G overlapping area. UE 300 can be in a connected state or an idle state. The overlapping area can refer to, for example, an area where a 4G cell connected to an EPC or 5G core exists.

[0051] UE 300 may include, for example, but not limited to, intelligent social robots, smartwatches, cellular phones, smartphones, personal digital assistants (PDAs), tablet computers, laptop computers, music players, video players, Internet of Things (IoT) devices, smart speakers, artificial intelligence (AI) devices, etc. UE 300 includes memory 310, a processor (e.g., including processing circuitry) 320, a communicator (e.g., including communication circuitry) 330, and a cell selector (e.g., including processing circuitry and / or executable program elements) 340.

[0052] Processor 320 is coupled to memory 310 and communicator 330. Processor 320 may include various processing circuitry, such as, but not limited to, general-purpose processors, such as central processing unit (CPU), application processor (AP), pure graphics processing unit such as graphics processing unit (GPU), visual processing unit (VPU), etc. Processor 320 may include multiple cores or may have a single core. Processor 320 is coupled to cell selector 340, memory 310 and communicator 330. Processor 320 may include various processing circuitry and may be configured to execute instructions stored in memory 310 and perform various other processes.

[0053] Memory 310 stores instructions to be executed by processor 320. Memory (310) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or various forms of erasable programmable read-only memory (EPROM) or electrically erasable programmable read-only memory (EEPROM). Additionally, in some examples, memory 310 may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" should not be interpreted as immovable. In some examples, memory 310 may be configured to store more information than is currently stored. In some examples, a non-transitory storage medium may store data that changes over time (e.g., in random access memory (RAM) or a cache).

[0054] The communicator 330 may include various communication circuits and can be configured for internal communication between internal hardware components and for communication with external devices via one or more networks. The communicator 330 may include standard-specific electronic circuitry that enables communication between internal hardware components and communication with external devices via one or more networks.

[0055] Cell selector 340 may include various processing circuitry and / or executable program elements and can be configured to search for the best available cell for the UE 300 to camp on. Cell selector 340 can select a cell when the UE is in a connected or idle state, and when the UE 300 is in any of Options 1, 2, and 7 of the 3GPP communication standard. According to 3GPP, Option 1 indicates that the UE 300 is in 4G standalone mode, where the UE 300 is connected to the eLTE radio and EPC (Evolved Packet Core). Option 2 indicates that the UE 300 is in 5G standalone mode, where the UE 300 is connected to the NR radio and 5G core. Option 3 indicates that the UE 300 is in 4G+5G mode, where the UE 300 is connected to the eLTE radio and 5G core.

[0056] In this embodiment, when UE 300 is powered on or in an idle state, the UE needs to camp on the cell for communication. The time spent by UE 300 should be very short. The method described below ensures minimal and / or reduced latency for UE 300, thereby improving latency.

[0057] In this embodiment, when searching for a cell to camp on, the cell selector 340 can create a combined MRU (Recently Used) list by merging a list of 4G MRU frequencies with a Public Land Mobile Network (PLMN) having a 5GC and a list of 5G MRU frequencies. The 4G MRU frequencies with a PLMN having a 5GC include 4G frequencies recently used by the UE 300 that also have a 5G core. The 5G MRU frequencies are the 5G frequencies recently used by the UE 300.

[0058] Cell selector 340 can perform a scan of the combined MRU list to determine whether either a 4G cell or a 5G cell with a 5G core is available for camping UE 300. A 4G cell is a cell that supports 4G radio and is connected to either the EPC or the 5G core. A 5G cell is a cell that supports 5G radio and is connected to the 5G core.

[0059] If a 4G cell with a 5G core is available, the UE 300 camps on the 4G cell with the 5G core. In one embodiment, if a 5G cell is available, the UE 300 camps on the 5G cell. In another embodiment, if both a 4G cell with a 5G core and a 5G cell are available, the cell selector 340 selects the 5G cell to camp on.

[0060] If neither a 4G cell with a 5G core nor a 5G cell is available, the cell selector 340 performs a 4G MRU frequency scan. A 4G MRU frequency scan is performed on a list of 4G MRU frequencies that do not have a 5G core. If a 4G cell with an EPC core is found, the UE 300 camps on that 4G cell. In this embodiment, after camping on a 4G cell with an EPC core, the UE determines whether a SIB (System Information Block) 24 message providing details about the NR radio exists. If the NR information exists, the UE searches for neighboring 5G cells to camp on. If the NR information does not exist, the UE 300 camps on a 4G cell that does not have a 5G core.

[0061] In this embodiment, if no cell is found in the 4G MRU scan, the cell selector 340 performs a 4G full-band scan and a 5G full-band scan in parallel. The 4G full-band scan includes scanning all available 4G frequencies in the 4G list, both with and without a 5G core, to find a 4G cell with or without a 5G core for camping the UE 300. The 5G full-band scan includes scanning all available 5G frequencies in the 5G list to find a 5G cell for camping the UE 300.

[0062] During parallel scanning of the 4G and 5G full-band frequencies, UE 300 can camp on either a 4G or 5G cell. If a 4G cell is found before a 5G cell, UE 300 camps on the 4G cell. The 4G cell camped by UE 300 during parallel scanning can have a PLMN supported by a 5GC or EPC. In this embodiment, the UE determines whether an SIB24 message providing details about the NR radio exists. If the NR information exists, the UE searches for neighboring 5G cells for camping. If the NR information does not exist, UE 300 camps on a 4G cell that does not have a 5GC.

[0063] If a 5G cell is found before a 4G cell, the UE 300 camps on the 5G cell. In this embodiment, if both a 4G cell and a 5C cell are found simultaneously, the UE 300 camps on the 5G cell.

[0064] If, during parallel scanning of the 4G and 5G full-band frequencies, UE 300 does not camp on any cell due to cell unavailability, UE 300 performs a conventional scan. A conventional scan involves scanning 3G frequencies, followed by 2G frequencies, to find a cell for UE 300 to camp on.

[0065] In this embodiment, when UE 300 is in a connected state, UE 300 performs a higher-priority PLMN search. The search for a higher-priority PLMN is explained in the 3GPP specification 3GPP SPTS 23.122 during the automatic network selection process.

[0066] UE 300 also determines the cell it is connected to. UE 300 performs 5G full-band scanning and 4G full-band scanning in parallel. If UE 300 determines that the cell it is connected to is a 5G cell, it performs a 5G full-band scan in the background. A 5G full-band scan is performed on the list of 5G frequencies, and a 4G full-band scan is performed on the list of 4G frequencies.

[0067] Cells found during the scan are reported to the upper layers. The upper layers are the mobile management layer and the application layer. Figure 3A A limited schematic diagram of UE300 is shown, but it should be understood that other embodiments are not limited thereto.

[0068] Figure 3B This is a block diagram illustrating an example configuration of a cell selector 340 according to various embodiments, which shows various components for selecting a cell for camping the UE 300 when the UE is present in an overlapping area of ​​5G SA, 5G non-SA and LTE.

[0069] Cell selector 340 includes a combined MRU list creator (e.g., including various processing circuits and / or executable program elements) 342, a 4G cell selector (e.g., including various processing circuits and / or executable program elements) 344, a 5G cell selector (e.g., including various processing circuits and / or executable program elements) 346, and a higher priority PLMN identifier (e.g., including various processing circuits and / or executable program elements) 348. When UE 300 is in idle mode, is powered on, or is recovering from out-of-service mode, UE 300 needs to camp on a cell for communication. Based on availability, the cell camped by UE 300 can be a 5G cell or a 4G cell.

[0070] As described above, existing methods first perform a 5G MRU scan, then a 4G MRU scan. If the cell is not found in the MRU frequency, the UE 300 performs a 5G full-band scan. If the cell is not found in the 5G full-band scan, the UE 300 performs a 4G full-band scan, due to significant (e.g., relatively long) latency. The current method reduces the latency in searching for cells to camp on the UE 300. The combined MRU list creator 342 may include various processing circuitry and / or executable program elements, and creates a combined MRU list by merging a list of 4G MRU frequencies with a PLMN supported by a 5GC and a list of 5G MRU frequencies. The 4G cell selector 344 and the 5G cell selector 346 may include various processing circuitry and / or executable program elements, and perform a scan on the combined MRU list to find 4G cells with a 5G core and 5G cells, respectively, for camping on the UE 300. If a 4G cell with a 5G core is found first, the UE 300 camps on the 4G cell with the 5G core, or if a 5G cell is found first, the UE camps on the 5G cell.

[0071] In an embodiment, if no cell for camping is found in the combined MRU list, the 4G cell selector 344 performs a scan of 4G MRU frequencies without a 5GC (with an EPC) to find a cell for camping UE 300. If a 4G cell with an EPC is found, UE 300 camps. In an embodiment, the UE (e.g., a higher-priority PLMN identifier 348) determines whether a SIB24 message providing details about the NR radio exists. If the NR information exists, the UE (e.g., a higher-priority PLMN identifier 348) searches for neighboring 5G cells for camping. If the NR information does not exist, UE 300 camps on a 4G cell without a 5GC.

[0072] If no 4G cell with an EPC is found in the list of 4G MRU frequencies with an EPC, then in parallel, the 5G cell selector 346 performs a 5G full-band scan and the 4G cell selector 344 performs a 4G full-band scan. A 4G full-band scan is performed on a list including all 4G frequencies with 5GC and EPC. A 5G full-band scan is performed on a list including all 5G frequencies. If the 5G cell selector 346 finds a 5G cell during the 5G full-band scan, then the UE 300 camps on the 5G cell found during the full-band scan and the 4G full-band scan is terminated. Similarly, if the 4G cell selector 344 finds a 4G cell during the 4G full-band scan, then the UE 300 camps on the 4G cell found during the full-band scan and the 5G full-band scan is terminated. In this embodiment, during a 4G full-band scan, the 4G cell selector 344 first searches for 4G cells with a 5GC, and if no 4G cell with a 5GC is found, the 4G cell selector 344 searches for 4G cells without a 5GC. In this embodiment, the UE determines whether an SIB24 message providing details about the NR radio exists. If the NR information exists, the UE searches for neighboring 5G cells to camp on. If the NR information does not exist, the UE 300 camps on a 4G cell without a 5GC.

[0073] If no cell for UE 300 is found after 4G full-band scanning and 5G full-band scanning, cell selector 340 performs a conventional scan.

[0074] When UE 300 is in connected mode, cell selector 340 uses higher priority PLMN identifier 348 to perform high priority PLMN scan.

[0075] Figure 4 This is a diagram created as an example of a list of MRUs according to various embodiments.

[0076] The 4G MRU frequencies include the 4G frequencies recently used by UE 300. The 4G MRU frequencies include two types of frequencies: 4G frequencies with a PLMN supporting 5GC (based on LTE cell indication, using IE:Cell AccessRelatedInfoList-5GC to support the 5G core network in SIB1) and 4G frequencies with a PLMN that does not support 5GC. The 5G MRU frequencies include the 5G frequencies recently used by UE 300.

[0077] At 402, the combined MRU list creator 342 merges a list including 5G MRU frequencies and a list including 4G MRU frequencies with PLMNs supported by 5GC. The 4G cell selector 344 and the 5G cell selector store 404 and scan 406 of the combined MRU list to select either a 4G cell or a 5G cell, respectively. The UE 300 camps 410 on the best available cell found after the combined MRU scan. If no cell is found after the combined MRU scan, a scan is performed on the list of 4G MRU frequencies, including those without 5GC.

[0078] Therefore, scanning two frequency lists together, namely the 5G MRU frequency list and the 4G MRU frequency list with PLMNs supported by 5GC, saves time compared to existing technologies, which first scan the 5G MRU frequencies, then scan the 4G MRU frequencies with 5GC, and then scan the 4G MRU frequencies without 5GC.

[0079] Figure 5 This is a diagram illustrating example interfaces for parallel scanning of 4G full-band scanning and 5G full-band scanning according to various embodiments.

[0080] like Figure 5 As shown, 502 indicates the 5G NAS communicating with 5G AS 504. Similarly, 506 indicates the 4G NAS communicating with 4G AS 508. A new interface has been introduced between 5G NAS 502 and 4G AS 508, which enables communication while simultaneously scanning the full 4G and 5G frequency bands.

[0081] In this embodiment, the new interface provides communication between the 5G NAS (upper layer) and the 4G AS (lower layer). The 5G NAS and 4GAS can exchange commands related to frequency band and PLMN selection.

[0082] Figure 6 This is a flowchart illustrating example methods for keeping the UE 300 camped in the 4G and 5G overlap area when the UE 300 is powered on or in OOS recovery mode, according to various embodiments.

[0083] At 602, the combined MRU list creator 342 merges a list including 5G MRU frequencies and a list of 4G MRU frequencies with a PLMN having a 5GC to create a combined MRU list. At 604A and 604B, the 4G cell selector 344 and the 5G cell selector 346 scan the combined MRU list to find a cell for camping the UE 300. At 606, the 4G cell selector 344 and the 5G cell selector 346 determine whether a 5G cell or a 4G cell with a PLMN having a 5GC has been found. If the cell is not found, the method performs operation 610. In an embodiment, at 608, in response to determining that the 5G cell selector 346 has found a 5G cell after scanning the combined MRU list, the UE 300 camps on the 5G cell. In this embodiment, at 608, in response to determining that the 4G cell selector 344 has found a 4G cell with a PLMN supporting 5GC, the UE 300 camps on the 4G cell with the PLMN supporting 5GC. Once the UE 300 camps at 608, the method flow stops here.

[0084] At 610, the 4G cell selector 344 scans a list including 4G MRU frequencies that do not have a 5GC. At 612, the cell selector 344 determines whether a 4G cell without a 5GC is found. If a 4G cell without a 5GC is found, the method proceeds to 614; otherwise, it proceeds to 616. At 614, the UE 300 camps on the 4G cell without a 5GC found after scanning the list including such cells. Once the UE 300 camps at 614, the method proceeds to 628. At 628, the UE determines whether an SIB24 message providing details about the NR radio exists. If the NR information exists, at 630, the UE searches for neighboring 5G cells to camp on, and the UE 300 camps on a 5G cell.

[0085] If the NR information is not present, then in 614, UE 300 camps on a 4G cell without 5GC, and the method procedure stops. However, if UE 300 is not camped at 614, then method procedure 600 is redirected to 616 and 618.

[0086] At point 616, the 5G cell selector 346 scans a list of all 5G frequencies, which can be referred to as a 5G full-band scan. At point 618, the 4G cell selector 344 scans a list of all 4G frequencies, which can be referred to as a 4G full-band scan in parallel with the 5G full-band scan at point 616. At point 620, the 4G cell selector 344 and the 5G cell selector 346 determine whether a 4G cell or a 5G cell with or without a PLMN is found for UE 300 to camp during the parallel scans of the 4G and 5G full-band scans. If a 4G cell with a 5GC is found, method 620 proceeds to 624. If a 5G cell is found, the method proceeds to 622. If neither a 4G cell with a 5GC nor a 5G cell is found, the method proceeds to 626. In this embodiment, UE 300 camps on whichever is found first, either the 4G cell with a 5GC or the 5G cell. For example, if a 5G cell is found first during the 5G full-band scan at 616, then UE 300 will camp on the 5G cell and the 4G full-band scan at 618 will be terminated.

[0087] At 624, UE 300 is camped on a 4G cell with 5GC found during the scan at 618 and the 5G full-band scan at 616 is terminated.

[0088] At 622, UE 300 is camped on the 5G cell found during the 5G full-band scan at 616 and the 4G full-band scan at 618 is terminated.

[0089] In the embodiment at 626, UE 300 camps on a 4G cell that does not have a 5GC, found during the 4G full-band scan at 618. In this embodiment, at 626, 4G cell selector 344 determines at 628 whether a SIB24 message providing details about the NR radio exists. If the NR information exists, cell selector 340 searches for a 5G cell for camping UE 300 and camps the UE at 630. If the NR information does not exist, UE 300 camps on a 4G cell that does not have a 5GC.

[0090] If the UE 300 does not camp on any cell after parallel scanning of the 4G full-band and 5G full-band, a conventional scan is performed to find a cell for the UE 300 to camp on.

[0091] Figure 7 This is a flowchart illustrating a method for keeping UE 300 stationed in a 4G and 5G overlapping area and in a connected state, according to various embodiments.

[0092] In this embodiment, UE 300 is already camped on any cell and is in connected mode. A higher-priority PLMN search is performed to camp UE 300 on a higher-priority cell.

[0093] Operations used for searching higher priority PLMNs Figure 7 The operations explained in the text are the same or similar.

[0094] At position 702, UE 300 is in a connected state and initiates a search for higher priority PLMNs. UE 300 scans the combined MRU list and then scans for 4G MRU frequencies that do not have 5GC.

[0095] Furthermore, steps 704 and 706 are executed in parallel. At step 704, a 5G full-band scan is performed. At step 706, a 4G full-band scan is performed. In this embodiment, if the 5G stack is in connected mode, the 5G full-band scan is performed in the background.

[0096] At point 708, a list of PLMNs including available cells is reported to higher levels.

[0097] Figure 8 This is a signal flow diagram illustrating example methods for keeping UE 300 camped in the 4G and 5G overlap area when UE 300 is powered on or in OOS recovery mode, according to various embodiments.

[0098] like Figure 8 As shown, 502 indicates 5G Non-Access Layer (5G-NAS), 506 indicates 4G Non-Access Layer (4G-NAS), 504 indicates 5G Standalone Network (5G-AS), and 508 indicates 4G Access Layer (4G-AS).

[0099] At 802, UE 300 is powered on or recovering from OOS mode. At 804, a combined MRU scan is performed on the list of 5G MRU frequencies and the list of 4G MRU frequencies with 5GC. At 806a, if a 5G cell is found after scanning the combined MRU list, UE 300 camps on the 5G cell. In an embodiment of 806b, if a 4G cell with a PLMN supporting 5GC is found, UE 300 camps on the 4G cell with the PLMN supporting 5GC.

[0100] If the UE 300 is not camped on any cell after the combined MRU scan, a full-band 5G scan is performed at 808 in parallel with the full-band 4G scan. In this embodiment, a scan of 4GMRU frequencies without 5GC is performed before the full-band scan is performed at 808.

[0101] In 810a, if a 5G cell is found during the full-band scan, UE 300 is camped on the 5G cell and the 4G full-band scan is terminated. In 810b, if a 4G cell with a 5G core is found first, UE 300 is camped on the 4G cell with the 5G core and the 5G full-band scan is terminated.

[0102] Figure 9 This is a signal flow diagram illustrating an example method for performing a higher-priority PLMN search for a resident UE 300 according to various embodiments.

[0103] like Figure 9 As shown, at 902, a higher-priority PLMN scan is performed. UE 300 can be in 5G connectivity mode, or it can be disconnected from the 5G stack. At 904, a 5G full-band scan is performed in parallel with the 4G full-band scan. If UE 300 is already connected to the 5G stack, the 5G full-band scan is performed in the background.

[0104] At step 906a, a 5G cell is found and the 4G full-band scan is terminated. At step 908a, UE 300 camps on the 5G cell. In this embodiment, if a 4G cell with 5GC is found at step 906b, the 5G full-band scan is terminated. At step 908b, UE 300 camps on the 4G cell with 5GC.

[0105] Figure 10A The diagram illustrates a conventional implementation according to the prior art, which indicates the latency of the UE camping on 4G when there is no stored frequency due to 5G scanning.

[0106] like Figure 10A As shown, UE 300 is located at location A and registered on 5G. UE 300 moves to another city at location B via airplane. During the journey, UE 300 is in airplane mode. Once it arrives at location B, airplane mode is turned off, and UE 300 scans for 5G MRU frequencies. If no cell is found, the UE performs a scan for 4G MRU frequencies. In this embodiment, if no cell is available in the 4G MRU scan, UE 300 performs a 5G full-band scan, and then a 4G full-band scan. If the 5G frequency is unavailable, UE 300 camps on a cell available in the 4G frequency. Therefore, as shown, there is a significant latency when UE 300 camps on a 4G cell.

[0107] Figure 10B This is a diagram illustrating example methods according to various embodiments.

[0108] like Figure 10BAs shown, UE 300 is located at location A and registered on 5G. UE 300 moves to another city at location B via aircraft. During the journey, UE 300 is in airplane mode. Once it arrives at location B, airplane mode is turned off, and UE 300 scans for 5G MRU frequencies in parallel with the 4G MRU frequencies, which is an MRU scan on the combined MRU list as described above. UE 300 camps on any cells found in the combined MRU scan, thus saving camping time.

[0109] However, if no cells are available in the combined MRU scan, UE 300 performs a 5G full-band scan in parallel with the 4G full-band scan. If the 5G frequency is unavailable, UE 300 camps on a cell available in the 4G frequency. Therefore, as shown in the figure, the latency of camping UE 300 is reduced.

[0110] Figure 10C This is a diagram illustrating example methods according to various embodiments.

[0111] like Figure 10C As shown, UE 300 is located at location A and registered on 5G. UE 300 moves to another city at location B via aircraft. During the journey, UE 300 is in airplane mode. Once it arrives at location B, airplane mode is turned off, and UE 300 scans for 5G MRU frequencies in parallel with the 4G MRU frequencies, which is an MRU scan on the combined MRU list as described above. UE 300 camps on any cells found in the combined MRU scan, thus saving camping time.

[0112] However, if no cell is available in the combined MRU scan, UE 300 performs a 5G full-band scan in parallel with the 4G full-band scan. UE 300 finds a 4G cell. Here, UE 300 finds the SIB24 message and reads the information about neighboring 5G cells from the SIB24 message. Therefore, UE 300 camps on the 5G cell based on the information present in the SIB24 message. Thus, as shown in the figure, the latency of camping UE 300 is reduced.

[0113] In an embodiment, if the UE 300 does not camp on any cell after parallel scanning of the 4G full-band and 5G full-band, a conventional scan is performed to find a cell for the UE 300 to camp on.

[0114] The embodiments disclosed herein can be implemented by at least one software program that runs on at least one hardware device and performs network management functions to control the elements.

[0115] The foregoing description of various example embodiments discloses the general nature of the embodiments herein. Others can readily modify various applications and / or adapt such specific embodiments to various applications by applying present knowledge without departing from the disclosed concept, and therefore, such adaptations and modifications should and are intended to be understood within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology used herein is for descriptive purposes and not for limitation.

[0116] While this disclosure has been illustrated and described with reference to various exemplary embodiments, it will be understood that these exemplary embodiments are intended to be illustrative and not restrictive. Those skilled in the art will further understand that various changes in form and detail, including the appended claims and their equivalents, may be made without departing from the true spirit and full scope of this disclosure.

Claims

1. A method for keeping a user equipment (UE) camped on a cell, based on the UE existing in an overlapping 5G and 4G region, the method comprising: The UE creates a combined MRU list by merging a list of recently used 4G MRU frequencies with 5G core 5GC and a list of 5G MRU frequencies. The UE determines whether one of the 4G cells and 5G cells with 5GC can be used to camp the UE by performing an MRU scan on the combined MRU list; as well as In response to determining, based on the MRU scan, that either the 4G cell with 5GC or the 5G cell is unavailable for camping the UE, a 4G MRU frequency scan is performed on the list of 4G MRU frequencies without 5GC. In response to the determination based on the 4G MRU frequency scan that a 4G cell without 5GC can be used to camp the UE, the UE camps on the 4G cell without 5GC. The MRU scan performed on the combined MRU list includes performing a 5G MRU frequency scan on the list of 5G MRU frequencies in parallel with performing a 4G MRU frequency scan on the list of 4G MRU frequencies with 5GC.

2. The method of claim 1, further comprising: In response to determining, based on the MRU scan, that one of the 5G cell and the 4G cell with 5GC can be used to camp the UE, the UE camps on the 4G cell with 5GC and the 5G cell.

3. The method of claim 1, further comprising: The system performs a 5G full-band scan of the list of 5G frequencies and a 4G full-band scan of the list of 4G frequencies in parallel, and camps the UE based on either the 5G full-band scan or the 4G full-band scan.

4. The method of claim 3, wherein camping the UE based on the 5G full-band scan or the 4G full-band scan comprises: The availability of a 4G cell is determined based on a full-band scan of the list of 4G frequencies, or the availability of a 5G cell is determined based on a full-band scan of the list of 5G frequencies, or both 4G and 5G cells are determined to be available; and The UE performs at least one of the following operations: In response to determining that the 4G cell is available based on the 4G full-band scan, the UE is kept camped on the 4G cell and the 5G full-band scan is terminated. In response to determining that the 5G cell is available based on the 5G full-band scan, the UE is camped on the 5G cell and the 4G full-band scan is terminated, or In response to determining that the 5G cell is available based on the 5G full-band scan and that the 4G cell is available based on the 4G full-band scan, the UE is camped on the 5G cell and the 4G full-band scan is terminated.

5. The method of claim 4, wherein in response to determining that the 4G cell is available based on the 4G full-band scan, the UE is camped on the 4G cell and the 5G full-band scan is terminated, further comprising: After camping on the 4G cell, the UE determines that the System Information Block 24 (SIB24) message includes information associated with the 5G cell; The UE searches for the 5G cell for camping on the UE based on SIB24 messages; and The UE will camp on the 5G cell found in the search.

6. The method of claim 1, wherein in response to determining, based on the 4G MRU frequency scan, that the 4G cell without 5GC is available for camping the UE, and camping on the 4G cell without 5GC, the method further comprises: After camping on the 4G cell that does not have 5GC, the UE determines that the SIB24 message includes information associated with the 5G cell; The UE searches for the 5G cell for camping on the UE based on the SIB24 message; and The UE will camp on the 5G cell found in the search.

7. The method of claim 4, wherein in response to determining that the 4G cell is available based on the 4G full-band scan, camping the UE on the 4G cell and terminating the 5G full-band scan includes making a 4G cell with 5GC prioritize camping the UE over a 4G cell without 5GC.

8. The method as described in claim 1, wherein the 5G and 4G overlapping area includes a 5G standalone network area, a 5G non-standalone network area, and a 4G area.

9. A user equipment (UE) configured to camp on a cell based on the UE's presence in an overlapping area of ​​5G and 4G, the UE comprising: Memory; A processor, coupled to a communicator including communication circuitry, is configured to control the UE for: A combined MRU list is created by merging a list of recently used 4G MRU frequencies with a Public Land Mobile Network (PLMN) featuring a 5G core 5GC and a list of 5G MRU frequencies. An MRU scan is performed on the combined MRU list to determine whether one of the 4G cells and the 5G cells with 5GC can be used to camp the UE. In response to the determination, based on the MRU scan of the combined MRU list, that one of the 4G cells with 5GC and the 5G cells is unavailable for camping the UE, a 4G MRU frequency scan is performed on the list of 4G MRU frequencies without 5GC, and In response to the determination based on the 4G MRU frequency scan that a 4G cell without 5GC can be used to camp the UE, the UE camps on the 4G cell without 5GC. The MRU scan performed on the combined MRU list includes: performing a 5G MRU frequency scan on the list of 5G MRU frequencies in parallel with performing a 4G MRU frequency scan on the list of 4G MRU frequencies with the 5GC.

10. The UE of claim 9, wherein the processor is configured to control the UE to: In response to determining, based on the MRU scan, that one of the 5G cell and the 4G cell with 5GC can be used to camp the UE, the UE camps on the 4G cell with 5GC and the 5G cell.

11. The UE of claim 9, wherein the processor is configured to control the UE to: The system performs a 5G full-band scan of the list of 5G frequencies and a 4G full-band scan of the list of 4G frequencies in parallel, and camps the UE based on either the 5G full-band scan or the 4G full-band scan.

12. The UE of claim 11, wherein camping the UE based on the 5G full-band scan or the 4G full-band scan comprises: Based on the 4G full-band scan of the list of 4G MRU frequencies or the 5G full-band scan of the list of 5G MRU frequencies, determine whether at least one of the 4G cells and 5G cells is available; and The UE performs at least one of the following operations: In response to the determination that the 4G cell is available based on 4G full-band scanning, the UE is kept camped on the 4G cell and the 5G full-band scanning is terminated. In response to determining that the 5G cell is available based on the 5G full-band scan, the UE is camped on the 5G cell and the 4G full-band scan is terminated, or In response to determining that the 5G cell is available based on the 5G full-band scan and that the 4G cell is available based on the 4G full-band scan, the UE is camped on the 5G cell and the 4G full-band scan is terminated.

13. The UE of claim 12, wherein responding to determining that the 4G cell is available based on the 4G full-band scan, camping the UE on the 4G cell and terminating the 5G full-band scan, further comprising: After camping on the 4G cell, the UE determines that the SIB24 message includes information associated with the 5G cell; The UE searches for the 5G cell for camping on the UE based on the SIB24 message; and The UE will camp on the 5G cell found in the search.

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