Method for causing a ue to acquire service using a preferred rat after detecting no service

Abstract

This disclosure relates to a method for enabling a UE to obtain service using a priority RAT after detecting no service. Techniques are provided for implementing a cell selection procedure after detecting no service to enable a user equipment (UE) to obtain service using a priority RAT. For example, some aspects of this disclosure relate to a method comprising determining, by the user equipment (UE), whether the UE has lost service, and in response to determining that the UE has lost service, initiating an initial cell selection (ICS) and starting a timer. The method further comprises determining whether a suitable cell has been identified during the ICS and determining whether the timer has expired. The method further comprises, in response to determining that no suitable cell has been identified during the ICS and that the timer has expired, suspending the ICS and performing intermediate stored information cell selection (ISICS) to identify a suitable cell.

Description

TECHNICAL FIELD

[0001] Aspects described herein generally relate to mechanisms for cell selection in wireless communications. BACKGROUND

[0002] After detecting no service, a user equipment (UE) performs a cell selection procedure to find a suitable cell to camp on. In some examples, the UE first attempts to find a suitable cell to camp on by performing a search on a stored list of carrier frequencies. In some examples, the UE attempts to find a suitable cell to camp on by performing a search on all carrier frequencies corresponding to each RAT that it supports. SUMMARY

[0003] Some aspects of the disclosure relate to apparatuses and methods for causing a UE to acquire service using a prioritized radio access technology (RAT) after detecting no service. For example, some aspects of the disclosure relate to apparatuses and methods for performing a cell selection on a list of frequencies corresponding to multiple prioritized RATs after a UE loses service.

[0004] Some aspects of the disclosure relate to a UE having a transceiver configured to enable wireless communication with a current serving cell and one or more potential serving cells, and a processor communicatively coupled to the transceiver. The processor is configured to determine whether the UE loses service and, in response to determining that the UE loses service, perform a stored information cell selection (SICS). The processor is further configured to determine whether a suitable cell is identified during the SICS and, in response to determining that a suitable cell is not identified during the SICS, initiate an initial cell selection (ICS) and start a timer. The processor is further configured to determine whether a suitable cell is identified during the ICS and determine whether the timer has expired. In response to determining that a suitable cell is not identified during the ICS and that the timer has expired, the processor is configured to suspend the ICS and perform an intermediate stored information cell selection (ISICS) to identify a suitable cell.

[0005] The processor can be further configured to determine whether a suitable cell is identified during the ISICS and, in response to determining that a suitable cell is not identified during the ISICS, the processor resumes the ICS and starts a second timer. The SICS includes performing a search on a stored list of frequencies associated with one or more previously used suitable cells. According to some aspects, the ICS includes performing a search on a plurality of frequencies corresponding to a plurality of RATs. According to some aspects, the ISICS includes performing a search on a stored list of frequencies corresponding to a plurality of prioritized RATs. According to some aspects, the ISICS includes performing a search on a plurality of frequencies corresponding to a last connected RAT, the last connected RAT corresponding to a last registered public land mobile network (PLMN).

[0006] Some aspects of the disclosure relate to a method that includes determining whether a UE loses service and performing a stored information cell selection (SICS) in response to determining that the UE loses service. The method further includes determining whether a suitable cell is identified during the SICS and initiating an initial cell selection (ICS) and starting a timer in response to determining that a suitable cell is not identified during the SICS. The method further includes determining whether a suitable cell is identified during the ICS and determining whether the timer has expired. In response to determining that a suitable cell is not identified during the ICS and in response to determining that the timer has expired, the method further includes suspending the ICS and performing an intermediate stored information cell selection (ISICS) to identify a suitable cell.

[0007] The method can further include determining whether a suitable cell is identified during the ISICS and resuming the ICS and starting a second timer in response to determining that a suitable cell is not identified during the ISICS. According to some aspects, the SICS includes performing a search of a stored list of frequencies associated with one or more previously used suitable cells. According to some aspects, the ICS includes performing a search of a plurality of frequencies corresponding to a plurality of RATs. According to some aspects, the ISICS includes performing a search of a stored list of frequencies corresponding to a plurality of prioritized RATs.

[0008] Some aspects of the disclosure relate to a non-transitory computer-readable medium storing instructions that, when executed by a processor of a UE, cause the processor to perform operations including determining whether the UE loses service and performing a stored information cell selection (SICS) in response to determining that the UE loses service. The operations further include determining whether a suitable cell is identified during the SICS and initiating an initial cell selection (ICS) and starting a timer in response to determining that a suitable cell is not identified during the SICS. The operations further include determining whether a suitable cell is identified during the ICS and determining whether the timer has expired and suspending the ICS and performing an intermediate stored information cell selection (ISICS) to identify a suitable cell in response to determining that a suitable cell is not identified during the ICS and determining that the timer has expired. According to some aspects, the SICS includes performing a search of a stored list of frequencies associated with one or more previously used suitable cells. According to some aspects, the ICS includes performing a search of a plurality of frequencies corresponding to a plurality of RATs. According to some aspects, the ISICS includes performing a search of a stored list of frequencies corresponding to a plurality of prioritized RATs.

[0009] The content of this invention is provided for illustrative purposes only, to provide an understanding of the subject matter described herein. Therefore, the features described above are merely illustrative and should not be construed as narrowing the scope or substance of the subject matter of this disclosure. Other features, aspects, and advantages of this disclosure will become apparent from the following detailed description, the accompanying drawings, and the claims. Attached Figure Description

[0010] The accompanying drawings, which are incorporated herein and form part of this specification, illustrate the present disclosure and, together with the specification, further serve to explain the principles of the disclosure and enable those skilled in the art to make and use the disclosure.

[0011] Figure 1 An exemplary system is shown that, according to some aspects of this disclosure, implements a cell selection procedure after detecting no service to enable the UE to obtain service using a priority RAT.

[0012] Figure 2 A block diagram of an exemplary system is shown that implements a cell selection procedure according to some aspects of this disclosure to enable a UE to obtain service using a preferred RAT.

[0013] Figure 3 An exemplary cell selection procedure following a UE loss of service is shown in accordance with some aspects of this disclosure.

[0014] Figure 4 An exemplary service recovery process using cell selection with intermediate storage information cell selection (ISICS) according to some aspects of this disclosure is shown.

[0015] Figure 5 An exemplary ISICS during the initial cell selection procedure is shown in accordance with some aspects of this disclosure.

[0016] Figure 6 An exemplary search cycle of a cell selection procedure that does not have ISICS features according to some aspects of this disclosure is shown.

[0017] Figure 7 An exemplary search cycle of a cell selection procedure with ISICS features according to some aspects of this disclosure is shown.

[0018] Figure 8 Exemplary methods for a system (e.g., a UE) to perform cell selection in accordance with some aspects of this disclosure so that the UE can obtain services using a preferred RAT are shown.

[0019] Figure 9 Exemplary methods for a system (e.g., a UE) to perform cell selection in accordance with some aspects of this disclosure so that the UE can obtain services using a preferred RAT are shown.

[0020] Figure 10 It is an exemplary computer system for implementing some aspects or parts thereof.

[0021] This disclosure is described with reference to the accompanying drawings. In the drawings, the same reference numerals generally denote the same or similarly functional elements. Additionally, the leftmost numeral of the reference numerals generally appears first in the drawings. Detailed Implementation

[0022] Some aspects of this disclosure relate to apparatus and methods for enabling a user equipment (UE) to obtain service using a priority RAT after no service is detected. For example, some aspects of this disclosure relate to apparatus and methods for performing cell selection after a UE loses service. According to some aspects, the UE performs a cell selection search using a priority RAT.

[0023] In some examples, aspects of this disclosure may be implemented by networks and / or UEs operating under Release 17 (Rel-17) and / or Rel-17 New Radio (NR) of fifth-generation (5G) radio technology for digital cellular networks as defined in the 3rd Generation Partnership Project (3GPP). Alternatively, aspects of this disclosure may be implemented by networks and / or UEs operating under Release 15 (Rel-15), Release 16 (Rel-16), etc. However, aspects of this disclosure are not limited to these examples, and one or more mechanisms of this disclosure may be implemented by other networks and / or UEs for cell selection procedures to enable the UE to obtain service using a preferred RAT.

[0024] Figure 1 An exemplary system 100 implementing a cell selection procedure according to some aspects of this disclosure is shown. The exemplary system 100 is provided for illustrative purposes only and is not intended to limit the aspects disclosed.

[0025] System 100 may include, but is not limited to, base stations 101 and 107 and user equipment 103. User equipment 103 may be configured to operate based on various wireless communication technologies. These technologies may include, but are not limited to, technologies based on the 3rd Generation Partnership Project (3GPP) standards. For example, UE 103 may be configured to operate using Rel-17 or other versions. UE 103 may include, but is not limited to, wireless communication devices, smartphones, laptops, desktop computers, tablets, personal assistants, monitors, televisions, wearable devices, Internet of Things (IoT) devices, vehicle communication devices, etc. Base stations 101 and 107 may include one or more nodes configured to operate based on various wireless communication technologies, such as, but not limited to, technologies based on 3GPP standards. For example, base stations 101 and 107 may include one or more nodes configured to operate using Rel-17 or other versions. Furthermore, base station 101 is associated with and provides services to cell 111. Similarly, base station 107 is associated with and provides services to cell 109. In some respects, even though both cells 111 and 109 can be used to provide radio services to UE 103, cell 111 may be preferred over cell 109 for various performance inferences (e.g., different available RATs), as those skilled in the art will understand.

[0026] Depending on some aspects, UE 103 may lose service from base station 101 to the currently serving cell 111. In order to obtain service, UE 103 attempts to associate with a suitable cell (such as cell 109) from multiple potential cells by scanning all supported radio bands.

[0027] According to some aspects, base stations 101 and 107 periodically broadcast a series of system information required for initial access at regular intervals. UE 103 can use the broadcast system information to perform initial access and initial connection to base station 101 or base station 107. Initial access can be performed using carrier signal 105, which may include one or more component carriers (CCs). In other words, UE 105 can use multiple carriers used for communication with base station 101 to implement carrier aggregation (CA).

[0028] According to some aspects, base station 107 implements NR radio access technology and periodically transmits Minimum System Information (MSI). The broadcast MSI includes the Master Information Block (MIB) and System Information Block 1 (SIB1). The MIB includes a limited number of most frequently transmitted parameters, which are essential for initial access to the network. The SIB includes parameters required to determine whether a cell is suitable for cell selection and information on the time-domain scheduling of other System Information Blocks.

[0029] According to some aspects, UE 103 performs a co-frequency search to scan cells using different scrambling codes at the same frequency. According to some aspects, UE 103 performs an inter-frequency search to scan cells using different frequencies. According to some aspects, UE 103 performs an inter-RAT search to find cells using different radio access technologies (RATs). Various RATs may include NR, E-UTRAN, UTRAN TDD, UTRAN FDD, CDMA2000, and GSM / EDGE.

[0030] Depending on some aspects, UE 103 performs the Initial Cell Selection (ICS) procedure or the Stored Information Cell Selection (SICS) procedure, for example, as described in Section 5.2.3 of 3GPP Technical Specification (TS) 38.304.

[0031] During the ICS procedure, UE 103 scans all RF frequencies corresponding to each RAT it supports. During the SICS procedure, UE 103 uses stored measurement information of the carrier frequency from previous carrier measurements, and optionally also uses cell parameter-related information from previously received measurement control information elements or from previously detected cells. Once the UE finds a suitable cell, it selects and pre-occupies that cell.

[0032] According to some aspects, UE 103 searches for the strongest cell on each carrier frequency, wherein the strongest cell on each carrier frequency may be determined based on one or more signal strength metrics or signal quality metrics obtained by UE 103. According to some aspects, signal strength metrics include Received Signal Strength Indication (RSSI), Received Signal Code Power (RSCP), and Reference Received Power (RSRP). According to some aspects, signal quality metrics include Signal-to-Interference-plus-Noise Ratio (SINR) and Reference Received Quality (RSRQ).

[0033] Figure 2 A block diagram of an exemplary system 200 is shown, which implements a cell selection procedure after detecting no service, according to some aspects of this disclosure, to enable a UE to obtain service using a preferred RAT. System 200 may be any of base station 101 or 107 of system 100 and / or UE 103. System 200 includes a processor 210, one or more transceivers 220a-220n, communication infrastructure 240, memory 250, operating system 252, application program 254, and antenna 260. The illustrated system is provided as an exemplary part of system 200, and system 200 may include other circuitry and subsystems. Furthermore, although the system of system 200 is shown as separate components, aspects of this disclosure may include any combination of these components, fewer components, or more components.

[0034] Memory 250 may include random access memory (RAM) and / or cache, and may include control logic (e.g., computer software) and / or data. Memory 250 may include other storage devices or memories, such as, but not limited to, hard disk drives and / or removable storage devices / cells. According to some examples, operating system 252 may be stored in memory 250. Operating system 252 may manage data transfer from memory 250 and / or one or more applications 254 to processor 210 and / or one or more transceivers 220a-220n. In some examples, operating system 252 may hold one or more network protocol stacks (e.g., Internet Protocol stack, cellular protocol stack, etc.) that may include multiple logical layers. At the corresponding layer of the protocol stack, operating system 252 includes control mechanisms and data structures to perform the functions associated with that layer.

[0035] According to some examples, application 254 may be stored in memory 250. Application 254 may include applications used by users of wireless system 200 (e.g., user applications). Applications in application 254 may include, but are not limited to, applications such as, but not limited to, wireless streams, video streams, remote control, and / or other user applications.

[0036] System 200 may also include communication infrastructure 240. Communication infrastructure 240 provides communication between, for example, processor 210, one or more transceivers 220a-220n, and memory 250. In some implementations, communication infrastructure 240 may be a bus. Processor 210, together with instructions stored in memory 250, performs operations such that system 200 of system 100 can implement a cell selection procedure to enable the UE to obtain service using the preferred RAT, as described herein, after detecting no service.

[0037] One or more transceivers 220a-220n transmit and receive communication signals that enable UE 103 to obtain service using a priority RAT after no service is detected, and may be coupled to antenna 260. Antenna 260 may include one or more antennas that may be the same or different types. One or more transceivers 220a-220n allow system 200 to communicate with other devices that may be wired and / or wireless. In some examples, one or more transceivers 220a-220n may include processors, controllers, radio components, sockets, plugs, amplifiers, filters, buffers, and similar circuitry / devices for connecting to and communicating over a network. According to some examples, one or more transceivers 220a-220n may include one or more circuitry for connecting to and communicating over wired and / or wireless networks.

[0038] According to some aspects, one or more transceivers 220a-220n may include a cellular subsystem, a WLAN subsystem, and / or Bluetooth. ™ The subsystems each include their own radio transceivers and protocols, as those skilled in the art will understand based on the discussion provided herein. In some specific implementations, one or more transceivers 220a-220n may include more or fewer systems for communicating with other devices.

[0039] In some examples, one or more transceivers 220a-220n may include one or more circuits (including a WLAN transceiver) for enabling connectivity and communication via a WLAN network (such as, but not limited to, networks based on the standards described in IEEE 802.11). Alternatively, one or more transceivers 220a-220n may include circuits for enabling, for example, Bluetooth-based... ™ Protocol, Bluetooth ™ Low power protocol or Bluetooth ™ One or more circuits for low-power remote protocol connectivity and communication (including Bluetooth) ™ (Transceiver). For example, transceiver 220n may include Bluetooth. ™ Transceiver.

[0040] Additionally, one or more transceivers 220a-220n may include one or more circuits (including cellular transceivers) for connecting to and communicating over a cellular network. Cellular networks may include, but are not limited to, 3G / 4G / 5G networks, such as Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), etc. For example, one or more transceivers 220a-220n may be configured to operate according to one or more of the 3GPP standards Rel-15, Rel-16, Rel-17, or other versions.

[0041] According to some aspects, processor 210, alone or in combination with computer instructions stored in memory 250 and / or one or more transceivers 220a-220n, implements a cell selection procedure after detecting no service to enable the UE to obtain service using the preferred RAT, as discussed herein.

[0042] Figure 3An exemplary service recovery procedure is illustrated when UE 103 loses service, according to some aspects of this disclosure. In this example, at 301, UE 103 acquires service from an LTE cell and connects to the LTE network. Subsequently, at 303, UE 103 temporarily loses service from the currently serving LTE cell 111. According to some aspects, UE 103 loses service from the serving cell when the quality of the LTE cell signal received by the UE deteriorates below the signal quality required for cell suitability. For example, when the UE enters an elevator or passes through a tunnel, causing radio signals to be blocked or attenuated, the UE temporarily loses service from the serving cell.

[0043] According to some sources, when a UE loses service, it can enter an idle state and not belong to a specific cell. As specified in 3GPP TS 38.304, the UE idle mode procedure includes Public Land Mobile Network (PLMN) selection, cell selection and reselection, and location registration.

[0044] Depending on several factors, the Non-Access Stratum (NAS) of UE 103 can select a PLMN. After selecting a PLMN, UE 103 can pre-occupy cells within the selected PLMN. At point 301, if UE 103 is not within the coverage area of ​​a registered PLMN, either a new PLMN will be automatically selected in automatic mode, or an indication of an available PLMN will be provided to the user of UE 103, allowing manual selection to be performed in manual mode.

[0045] According to some aspects, once UE 103 selects a PLMN, NAS can perform a cell selection procedure to select a suitable cell for that PLMN and pre-occupy it. UE 103 can perform cell selection by searching all supported carrier frequencies for each supporting RAT until it finds a suitable cell. According to some aspects, NAS controls the RAT used by UE 103 to perform cell selection. NAS indicates the RAT associated with the selected PLMN and maintains a list of prohibited registration areas and a list of equivalent PLMNs.

[0046] According to some aspects, UE 103 may select a suitable cell based on RRC_IDLE or RRC_INACTIVE state measurements and cell selection criteria. Section 4.5 of 3GPP TS 38.304 specifies the conditions that can be met to consider a cell as a suitable cell, wherein a suitable cell is part of a PLMN in the list of selected PLMNs, registered PLMNs, or equivalent PLMNs. According to some aspects, a suitable cell is not part of a tracking area that is in the list of prohibited roaming tracking areas and does not have a prohibited state.

[0047] According to some aspects, for example, a suitable cell satisfies cell selection criteria as specified in Section 5.2.3.2 of 3GPP TS 38.304 or Section 5.2.3.2 of 3GPP TS 36.304. According to some aspects, cell selection criterion S is satisfied when the cell selection reception level and quality level are both above a given value: Srxlev > 0 and Squal > 0, where Srxlev is the cell selection reception level and Squal is the cell selection quality level in decibels.

[0048] According to some aspects, if UE 103 cannot find a suitable cell using any frequency or RAT, UE 103 may attempt to find an acceptable cell. An acceptable cell is one that the UE can reserve to obtain less service than that provided by a suitable cell. According to some aspects, an acceptable cell meets cell selection criteria and is not in a prohibited state.

[0049] According to some aspects, UE 103 can select a PLMN associated with multiple RATs. At 303, UE 103 can initiate a Stored Information Cell Selection (SICS) procedure. According to some aspects, the SICS procedure utilizes stored information of previously used carrier frequencies and optional cell parameter information from previously received measurement control information elements or from previously detected cells. During the SICS procedure, UE 103 can perform a search on a list of stored frequencies associated with one or more previously used suitable cells.

[0050] At point 305, UE 103 completes the SICS procedure. If UE 103 finds a suitable cell during the SICS procedure, it selects that cell for pre-occupancy. If UE 103 does not find a suitable cell during the SICS procedure, it may initiate the Initial Cell Selection (ICS) procedure. According to some aspects, during the ICS procedure, UE 103 may scan all RF frequencies in the carrier band based on its ability to find a suitable cell. UE 103 may scan each carrier frequency to identify the strongest cell transmitting on that carrier frequency.

[0051] At 305, assuming no suitable cell is found through the SICS procedure, UE 103 initiates the initial cell search procedure. In this example, UE 103 initiates ICS by scanning the RF frequencies corresponding to the LTE RAT associated with the previously serving cell. At 307, UE 103 completes the scan of the RF frequencies corresponding to the LTE RAT. However, at 307, UE 103 still has no service relative to the last serving LTE cell 111. Furthermore, in this example, UE 103 did not find a suitable cell through the LTE RAT and subsequently continued scanning RF frequencies for other RATs in the previously serving PLMN.

[0052] At 309, LTE cell 111, the last serving cell previously reserved by UE 103, can be used again by UE 103. However, UE 103 cannot resume service of the now available LTE cell 111 because it is performing the initial cell search procedure using a non-LTEAT. In this example, UE 103 scans all RF frequencies corresponding to each supported RAT. At 311, UE 103 completes the ICS procedure without finding a suitable cell.

[0053] Depending on several aspects, the cell selection search cycle may include one round of SICS procedure and one round of initial cell search procedure, followed by a sleep phase of a predetermined duration. After completing the search cycle, UE 103 may enter a sleep state for a predetermined amount of time. After the predetermined sleep duration, UE 103 may exit the sleep state and initiate the next search cycle.

[0054] At point 313, UE 103 exits sleep mode and begins a new search cycle by initiating a SICS procedure. During the SICS procedure, UE 103 uses a stored list of frequencies, including the frequency band corresponding to cell 111. In this example, since LTE cell 111 is now available, UE 103 selects cell 111 and reacquires service. Figure 3 In the example shown, the UE remains without service until a new search cycle begins, even when previously pre-occupied cells become connectable and service is restored. Furthermore, because UE 103 supports multiple RATs, each search cycle involves scanning a large number of frequencies. Therefore, the time without service experienced by UE 103 is significantly prolonged.

[0055] Figure 4 An exemplary service recovery procedure with Intermediate Stored Information Cell Selection (SICS) features is illustrated according to some aspects of this disclosure. According to some aspects, after a UE loses service to its current serving cell, performing a cell selection procedure using Intermediate Stored Information Cell Selection (ISICS) to identify a suitable cell can reduce the UE's service outage time. According to some aspects, the ISICS procedure can enable the UE to obtain service using a preferred RAT after service outage is detected.

[0056] In this example, at point 401, UE 103 acquires service from an LTE cell connected to the LTE network. Subsequently, at point 403, the UE detects that it has lost service from the current serving cell. Depending on some aspects, a UE may lose service from its current serving cell when the signal quality received by the UE falls below a certain threshold.

[0057] According to some aspects, in response to the detection of service loss, the UE initiates a cell selection procedure. At 403, the UE performs a SICS procedure to identify a suitable cell. According to some aspects, during the SICS procedure, the UE may scan a previously used list of stored carrier frequencies. Additionally, during SICS, the UE may optionally use cell parameters from previously received measurement control information or related information from cell parameters of previously detected cells.

[0058] Depending on several aspects, if UE 103 fails to find a suitable cell during the SICS procedure, it may initiate an Initial Cell Search (ICS) procedure and start an Intermediate Stored Information Cell Selection (ISICS) timer. During the ICS procedure, the UE may scan all carrier frequencies in each of its supported RATs. The UE may scan each carrier frequency to identify the strongest cell transmitting on that carrier frequency.

[0059] At 405, in response to determining that no suitable cell was identified during the SICS procedure, UE 103 initiates the ICS procedure and starts the Intermediate Stored Information Cell Selection (ISICS) timer. At 407, the previously serving cell becomes available to the UE. As a non-limiting example, a previously serving cell may become available to the UE after a temporary loss of service, such as when the UE leaves a tunnel after passing through it, when the UE leaves an elevator, or when the UE clears some other signal obstruction. In this example, at 407, the UE cannot resume service on the LTE cell because the UE has completed the LTE band scan as part of the ICS procedure before the LTE cell becomes available at 407. Therefore, in this example, even when the previously reserved cell becomes available, the UE cannot resume service.

[0060] According to some sources, when the ISICS timer expires, UE 103 can pause the ongoing ICS procedure and initiate an ISICS procedure.

[0061] According to some aspects, UE 103 may maintain a priority RAT list by storing priority RATs and their corresponding frequencies in a memory such as memory 250. During intermediate SICS procedures, UE 103 scans all RF frequencies corresponding to each priority RAT. According to some aspects, the priority RAT list may include RATs corresponding to the nearest cell previously reserved by UE 103. According to some aspects, the priority RAT list may include the last registered RAT.

[0062] According to some aspects, UE 103 can scan the RF frequencies corresponding to the priority RAT according to a predefined priority order. According to some aspects, the NR RAT can be a RAT with higher priority than LTE. According to some aspects, the LTE RAT can be a RAT with higher priority than UMTS RAT. According to some aspects, the UMTS RAT can be a RAT with higher priority than GSM RAT. According to some aspects, the last registered RAT can be a RAT with higher priority than LTE.

[0063] At 409, in response to the expiration of the ISICS timer, the UE executes the ISICS procedure. As a non-limiting example, the priority RAT list includes the LTE RATs corresponding to the most recent cells previously pre-occupied by UE 103. As a non-limiting example, during the ISICS procedure, the UE scans for frequencies corresponding to the LTE RATs. In this example, the UE identifies the currently available previously serving cells as suitable cells, selects the suitable cell, and pre-occupies it to restore service.

[0064] According to some aspects, the ISICS timer duration is configurable and can be set to be less than the time that UE 103 might take to complete the initial cell selection search. In other words, refer to Figure 4 409 occurs before the end of the ICS that begins at 405. According to some aspects, the duration of the intermediate SICS timer may be less than the time it might take for UE 103 to complete scanning of frequencies corresponding to the NR band. According to some aspects, the duration of the intermediate SICS timer may be less than the time it might take for UE 103 to complete scanning of frequencies corresponding to the LTE or UMTS band. According to some aspects, the duration of the ISICS timer may depend on the number of RATs supported by the UE.

[0065] At point 411, the UE preempts the previously served LTE cell and resumes service. In this example, because the timer duration is less than the duration required for the UE to complete the ICS search cycle, the UE resumes service before completing the entire ICS search cycle. Therefore, in this example, the UE experiences less service time due to the ISICS procedure.

[0066] Figure 5 An exemplary ISICS phase during the initial cell selection procedure is illustrated according to some aspects of this disclosure. In this example, the UE fails to find a suitable cell even after the ISICS search cycle is completed. According to some aspects, if the UE fails to identify a suitable cell during the ISICS procedure, it may resume the suspended ICS procedure. According to some aspects, the UE resumes the ICS procedure and continues scanning frequencies corresponding to its supported RATs. According to some aspects, the UE may resume the ICS procedure and start another ISICS timer.

[0067] In this example, at 501, UE 103 acquires service from an LTE cell connected to the LTE network. At 503, the UE loses service and executes a SICS procedure to identify a suitable cell. At 505, in response to determining that no suitable cell was found during the SICS procedure, the UE initiates an ICS procedure and starts an ISICS timer. At 507, based on the expiration of the ISICS timer, the UE pauses the ICS procedure and executes an ISICS procedure. At 509, based on determining that no suitable cell was identified during the ISICS procedure, the UE resumes the paused ICS and starts a second ISICS timer. Subsequently, at 511, the UE completes the ICS procedure. At 511, based on determining that no suitable cell was identified after completing the search cycle, the UE enters sleep mode for a predetermined duration. At 513, the UE initiates another round of the SICS procedure to find a suitable cell. At 515, based on determining that no suitable cell was identified during the SICS procedure, the UE starts another round of the ICS procedure and starts an ISICS timer.

[0068] Figure 6 An exemplary search cycle of a cell selection procedure without the Intermediate Stored Information Cell Selection (ISICS) feature according to some aspects of this disclosure is shown. As a non-limiting example, each search cycle 610 and 620 includes a SICS phase and an ICS phase, followed by a sleep period 630 of predetermined duration. According to some aspects, the UE performs a search on a stored list of frequencies corresponding to its supported RATs. As a non-limiting example, the UE supports 5G, 4G, 3G, and 2G RATs. Based on the determination that no suitable cell was identified during the SICS phase, the UE may initiate an ICS procedure. During the ICS procedure, the UE scans all frequencies for each of its supported RATs.

[0069] At 601, the UE initiates the SICS phase and scans the stored frequency list corresponding to the 4G RAT. At 603, 605, and 607, the UE scans the stored frequency lists corresponding to the 5G RAT, 3G RAT, and 2G RAT, respectively, with the SICS phase extending from 601 to 607. At 609, based on the fact that no suitable RAT was found during the SICS phase, the UE initiates ICS and scans all frequencies corresponding to the 4G RAT. At 611, 613, and 615, the UE scans all frequencies corresponding to the 5G RAT, 3G RAT, and 2G RAT, respectively. In this non-limiting example, the ICS phase extends from 609 to 615. According to some aspects, the UE may enter a sleep mode for a predetermined duration at the end of the ICS phase. At 617, the UE exits the sleep mode and initiates another SICS phase for another search cycle.

[0070] Figure 7 An exemplary search cycle of a cell selection procedure with ISICS features according to some aspects of this disclosure is shown. According to some aspects, each search cycle 710 and 720 includes a SICS phase and an ICS phase, followed by a sleep period 730 of predetermined duration. According to some aspects, the UE can perform a search on a stored list of frequencies corresponding to its supported RATs. As a non-limiting example, the UE supports 5G, 4G, 3G, and 2G RATs. Based on the determination that no suitable cell is identified during the SICS phase, the UE initiates an initial cell search procedure and starts an ISICS timer. During the ICS phase, the UE can scan all frequencies for each supported RAT. When the ISICS timer expires, the UE pauses the ongoing ICS procedure and executes an ISICS procedure. Based on the determination that no suitable cell is found during the ISICS procedure, the UE can resume the paused ICS procedure and start a second timer for the next ISICS procedure.

[0071] At 701, UE 103 initiates the SICS phase and scans the stored frequency list corresponding to the 4G RAT. At 703, 705, and 707, the UE scans the stored frequency lists corresponding to the 5G RAT, 3G RAT, and 2G RAT, respectively. In this non-limiting example, the SICS phase extends from 701 to 707. Based on the determination that no suitable cell was identified during the SICS phase, the UE initiates the ICS phase and starts an ISICS timer. At 709, the UE performs ICS by scanning a portion of the frequencies corresponding to the 4G RAT. At 711, in response to the ISICS timer expiring, the UE suspends the ICS scan of the 4G band and performs the ISICS procedure. At 713, based on the determination that no suitable cell was identified during the ISICS procedure, the UE resumes the ICS scan and starts a configurable timer for the next ISICS procedure. At 715, in response to the ISICS timer expiring, the UE may suspend the ICS scan and perform the ISICS procedure. At 717 and 721, the UE scans the frequencies corresponding to the 5G RAT. At positions 725 and 729, the UE scan corresponds to the frequencies of the 3G RAT. At positions 733 and 737, the UE scan corresponds to the frequencies of the 2G RAT.

[0072] In this non-limiting example, the ICS phase extends from 709 to 737. Additionally, ICS scanning is optionally paused at regular intervals to perform ISICS procedures at 711, 715, 719, 723, 727, 731, and 735. According to some aspects, if the UE fails to identify a suitable cell after completing the ICS procedure, the UE may enter sleep mode 730 for a predetermined amount of time. At 739, the UE exits sleep mode and initiates the SICS phase of search cycle 720. In this non-limiting example, the duration of the ISICS timer is less than the duration taken by the UE 103 to complete scanning of frequencies corresponding to the 5G RAT, 4G RAT, 3G RAT, or 2G RAT. The time taken by the UE to scan frequencies corresponding to a RAT during the ICS procedure may vary depending on the RAT. Therefore, for some RATs, more than one ISICS procedure may be performed per search cycle.

[0073] Figure 8 An exemplary method 800 is shown, according to some aspects of this disclosure, for a system (e.g., a UE) to perform cell selection after detecting no service, so that the UE can obtain service using a preferred RAT. For convenience, and not limitation, please contact Figures 1-7 Element description Figure 8 Method 800 can represent Figure 1 After detecting no service, UE 103 performs a cell selection procedure to enable the UE to obtain service using the preferred RAT. Method 800 can also be... Figure 2 System 200 and / or Figure 10 The method is executed by computer system 1000. However, method 800 is not limited to the specific aspects depicted in the figures, and other systems may be used to execute the method, as those skilled in the art will understand. It should be understood that not all operations may be necessary, and these operations may not be compatible with... Figure 8 Execute in the same order as shown.

[0074] At point 802, the UE detects the loss of service from its current serving cell. For example, the UE loses service when the signal quality received by the UE deteriorates below the signal quality required for cell suitability. Depending on some aspects, in response to the detection of service loss, the UE initiates a cell selection procedure to identify and select a suitable cell to pre-occupy.

[0075] At 804, the Non-Access Stratum (NAS) at the UE performs a Stored Information Cell Selection (SICS) procedure to identify a suitable cell. However, the SICS procedure can be an optional step. For example, based on the determination that the UE has lost service from the current serving cell, the UE can proceed directly to initiating an ICS procedure without performing the SICS procedure. According to some aspects, the SICS procedure may include performing a search on a stored list of frequencies associated with one or more previously used suitable cells. The SICS procedure may include performing a search on the stored list of frequencies, wherein the stored list of frequencies scanned by the UE during SICS may correspond to multiple Radio Access Technologies (RATs) supported by the UE. For example, the multiple RATs supported by the UE may include New Radio (NR), Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS), and Global System for Mobile Communications (GSM).

[0076] At 806, the UE determines whether a suitable cell has been identified during the SICS procedure. According to some aspects, a suitable cell meets cell selection criteria, which can be satisfied when the cell selection reception level and / or quality level is higher than a given value, i.e., Srxlev > 0 and Squal > 0. According to some aspects, a suitable cell can be part of a PLMN in the selected PLMN, registered PLMN, or equivalent PLMN list. According to some aspects, a suitable cell is not part of a tracking area that is in the list of prohibited roaming tracking areas and is not in a prohibited state. At 808, if a suitable cell is identified during the SICS procedure, the UE may pre-claim that cell.

[0077] At point 810, if no suitable cell is identified during the SICS procedure, the UE initiates an Initial Cell Search (ICS) procedure and starts an Intermediate Stored Information Cell Selection (ISICS) timer. According to some aspects, the NAS layer at the UE can start the ISICS timer. According to some aspects, the ISICS timer duration is configurable and can be set to be less than the time the UE might take to complete the ICS. According to some aspects, the ISICS timer duration can be less than the time the UE might take to complete scanning frequencies corresponding to NR bands. According to some aspects, the ISICS timer duration can be less than the time the UE might take to complete scanning frequencies corresponding to LTE or UMTS bands. According to some aspects, the ISICS timer duration can depend on the number of RATs supported by the UE.

[0078] At 812, the UE begins executing the ICS procedure. During the ICS phase, the UE can scan all frequencies for each RAT it supports. For example, during ICS, the UE can scan all frequencies corresponding to the 5G RAT, 4G RAT, 3G RAT, and 2G RAT. Depending on some aspects, the UE can scan each carrier frequency to identify the strongest cell transmitting on that carrier frequency. At 814, the UE determines whether a suitable cell has been identified during the ongoing ICS procedure. If the UE identifies a suitable cell during the ICS procedure, the UE can pre-claim the identified suitable cell.

[0079] At point 816, the UE determines whether the ISICS timer has expired. If the UE has not yet identified a suitable cell and the ISICS timer has not expired, the UE continues to execute the ICS procedure. However, if the UE has not yet identified a suitable cell but the ISICS timer has expired, the UE suspends the ICS procedure and executes the ISICS procedure.

[0080] At point 818, in response to determining that the timer has expired, the UE suspends the ongoing ICS scan and executes the ISICS procedure to identify a suitable cell using a priority RAT. According to some aspects, during the intermediate SICS procedure, the UE may scan frequencies corresponding to multiple priority RATs. According to some aspects, the priority RAT list may include the RAT corresponding to the last serving cell. According to some aspects, the priority RAT list includes the last registered RAT. According to some aspects, during the ISICS procedure, the UE scans the RF frequencies corresponding to the priority RATs according to a predetermined priority order. According to some aspects, the NR RAT may be a RAT with higher priority than LTE. According to some aspects, the LTE RAT may be a RAT with higher priority than UMTS. According to some aspects, the UMTS RAT may be a RAT with higher priority than GSM. According to some aspects, the last registered RAT may be a RAT with higher priority than LTE. According to some aspects, the last registered RAT may be a RAT with higher priority than LTE.

[0081] Figure 9 An exemplary method 900 is shown, according to some aspects of this disclosure, for a system (e.g., a UE) to perform cell selection after detecting no service, so that the UE can obtain service using a preferred RAT. For convenience, and not limitation, please contact Figures 1-8 Element description Figure 9 Method 900 can represent an electronic device (e.g., Figure 1 UE 103) performs a cell selection procedure after detecting no service to enable the UE to obtain service using the preferred RAT. Method 900 can also be performed by Figure 2 System 200 and / or Figure 10The method is executed by computer system 1000. However, method 900 is not limited to the specific aspects depicted in the figures, and other systems may be used to execute the method, as those skilled in the art will understand. It should be understood that not all operations may be necessary, and these operations may not be compatible with... Figure 9 Execute in the same order as shown.

[0082] At 902, the UE executes the ISICS procedure to identify a suitable cell using the priority RAT. At 904, the UE determines whether a suitable cell was identified during the ISICS procedure. At 906, if the UE identified a suitable cell during the ICS procedure, the UE may pre-claim the identified cell. At 908, if a suitable cell was not identified during the ISICS procedure, the UE may resume the suspended ICS procedure and start a timer for the next ISICS procedure.

[0083] For example, one or more computer systems such as Figure 10 The computer system 1000 shown implements these aspects. The computer system 1000 can be any well-known computer capable of performing the functions described herein, such as… Figure 1 Devices 101, 103 and / or Figure 2 The computer system 1000 includes one or more processors (also referred to as a central processing unit or CPU), such as processor 1004. Processor 1004 is connected to communication infrastructure 1006 (e.g., a bus). The computer system 1000 also includes user input / output devices 1003, such as a monitor, keyboard, pointing device, etc., that communicate with communication infrastructure 1006 via user input / output interface 1002. The computer system 1000 also includes main memory or primary memory 1008, such as random access memory (RAM). Main memory 1008 may include one or more levels of cache. Main memory 1008 stores control logic components (e.g., computer software) and / or data.

[0084] The computer system 1000 may also include one or more auxiliary storage devices or memories 1010. Auxiliary memory 1010 may include, for example, a hard disk drive 1012 and / or a removable storage device or drive 1014. The removable storage drive 1014 may be a floppy disk drive, a magnetic tape drive, an optical disk drive, an optical storage device, a magnetic tape backup device, and / or any other storage device / drive.

[0085] Removable storage drive 1014 can interact with removable storage unit 1018. Removable storage unit 1018 includes a computer-usable or readable storage device in which computer software (control logic components) and / or data are stored. Removable storage unit 1018 can be a floppy disk, magnetic tape, optical disc, DVD, optical storage disc, and / or any other computer data storage device. Removable storage drive 1014 reads from and / or writes to removable storage unit 1018 in a well-known manner.

[0086] According to some aspects, the auxiliary storage 1010 may include other means, tools, or other methods for allowing computer system 1000 to access computer programs and / or other instructions and / or data. Such means, tools, or other methods may include, for example, removable storage unit 1022 and interface 1020. Examples of removable storage unit 1022 and interface 1020 may include program boxes and box interfaces (such as those found in video game devices), removable memory chips (such as EPROM or PROM) and associated sockets, memory sticks and USB ports, memory cards and associated memory card slots, and / or any other removable storage units and associated interfaces.

[0087] Computer system 1000 may also include a communication or network interface 1024. Communication interface 1024 enables computer system 1000 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referred to by reference numeral 1028). For example, communication interface 1024 may allow computer system 1000 to communicate with remote device 1028 via communication path 1026, which may be wired and / or wireless, and may include any combination of LAN, WAN, Internet, etc. Control logic components and / or data may be transmitted to and from computer system 1000 via communication path 1026.

[0088] The operations described in the foregoing aspects can be implemented in various configurations and architectures. Therefore, some or all of the operations described in the foregoing aspects can be performed in hardware, software, or both. In some aspects, tangible, non-transitory devices or articles of art include tangible, non-transitory computer-usable or readable media on which control logic components (software) are stored, also referred to herein as computer program products or program storage devices. This includes, but is not limited to, computer system 1000, main memory 1008, secondary memory 1010, and removable storage units 1018 and 1022, and tangible articles embodying any combination thereof. When executed by one or more data processing devices (such as computer system 1000), such control logic components cause such data processing devices to operate as described herein.

[0089] Based on the teachings contained in this disclosure, it will be apparent to those skilled in the art how to use [other methods]. Figure 10 Other data processing devices, computer systems, and / or computer architectures besides those shown may be used to make and use aspects of this disclosure. In particular, aspects may operate in conjunction with software, hardware, and / or operating system implementations other than those described herein.

[0090] It should be understood that the Detailed Description section, rather than the Summary and Abstract section, is intended to be used to interpret the claims. The Summary and Abstract section may set forth one or more, but not all, exemplary aspects of this disclosure as contemplated by the inventors, and is therefore not intended to limit this disclosure or the appended claims in any way.

[0091] Although this disclosure has been described herein with reference to exemplary aspects of exemplary fields and applications, it should be understood that this disclosure is not limited thereto. Other aspects and modifications are possible and are within the scope and spirit of this disclosure. For example, and without limiting the generality of this paragraph, the aspects are not limited to the software, hardware, firmware, and / or entities shown in the figures and / or described herein. Furthermore, the aspects (whether explicitly described herein or not) have significant utility for fields and applications beyond those illustrated herein.

[0092] The aspects have been described here using functional building blocks that illustrate specific implementations of functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries can be defined as long as the specified functions and relationships (or their equivalents) are performed appropriately. Furthermore, alternative aspects may perform functional blocks, steps, operations, methods, etc., in a different order than that described herein.

[0093] References to “an aspect,” “aspect,” “an example,” “example,” or similar phrases herein indicate that the aspect described may include a particular feature, structure, or characteristic, but each aspect may not necessarily include that particular feature, structure, or characteristic. Furthermore, such wording does not necessarily refer to the same aspect. Additionally, when a particular feature, structure, or characteristic is described in conjunction with an aspect, whether or not it is explicitly mentioned or described herein, the combination of those features, structures, or characteristics with other aspects is within the knowledge of a person skilled in the art.

[0094] The breadth and scope of this disclosure should not be limited by any of the foregoing exemplary aspects, but should be defined solely by the following claims and their equivalents.

[0095] This disclosure assumes that entities responsible for collecting, analyzing, disclosing, transmitting, storing, or otherwise using such personal information data will comply with established privacy policies and / or privacy practices. Specifically, such entities should implement and adhere to privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy and security of personal information data. Such policies should be easily accessible to users and should be updated as data collection and / or use change. Personal information from users should be collected for the entity's lawful and reasonable purposes and not shared or sold outside of these lawful uses. Furthermore, such collection / sharing should only occur upon receipt of the user's informed consent. In addition, such entities should consider taking any necessary steps to protect and safeguard access to such personal information data and ensure that others with access to such personal information data comply with their privacy policies and processes. Additionally, such entities may be subject to third-party evaluations to demonstrate their compliance with widely accepted privacy policies and practices. Furthermore, policies and practices should be adapted to the specific types of personal information data collected and / or accessed, and to applicable laws and standards, including specific considerations regarding jurisdiction. For example, in the United States, the collection or access to certain health data may be governed by federal and / or state laws, such as the Health Insurance Transfer and Accountability Act (HIPAA); while in other countries, health data may be subject to other regulations and policies and should be handled accordingly. Therefore, different privacy practices should be maintained for different types of personal data in each country.

Claims

1. A user equipment (UE), comprising: A transceiver configured to enable wireless communication with the current serving cell and one or more potential serving cells; and A processor, communicatively coupled to the transceiver and configured to: Determine whether the UE has lost service from the current serving cell; In response to determining that the UE has lost service from the current serving cell, an Initial Cell Selection (ICS) is initiated and an Intermediate Stored Information Cell Selection (ISICS) timer is started, wherein the ICS performs a search for multiple frequencies corresponding to multiple Radio Access Technologies (RATs), and wherein the duration of the ISICS timer is less than the time required to search for all of the multiple frequencies during the ICS. Determine whether a suitable cell was identified during the ICS period and whether the ISICS timer has expired; as well as In response to determining that no suitable cell was identified during the ICS and that the ISICS timer has expired, the ICS is paused and an ISICS is performed to identify a suitable cell, wherein the ISICS performs a search on a stored list of frequencies corresponding to a plurality of priority RATs, which are subsets of the plurality of RATs, during the pause of the ICS.

2. The UE according to claim 1, wherein the processor is further configured to: Determine whether a suitable cell was identified during the ISICS process; and In response to the determination that no suitable cell was identified during the ISICS, the ICS is restored and a second timer is started.

3. The UE according to claim 1, wherein the processor is further configured to: In response to determining that the UE has lost service from the current serving cell, a stored information cell selection (SICS) is performed and it is determined whether a suitable cell has been identified during the SICS; and In response to determining that no suitable cell was identified during the SICS, the ICS was initiated and the ISICS timer was started.

4. The UE of claim 3, wherein the SICS includes performing a search on a stored list of frequencies associated with one or more previously used suitable cells.

5. The UE of claim 1, wherein the ISICS includes performing a search for a plurality of frequencies corresponding to the last connected radio access technology (RAT) and the last registered public land mobile network (PLMN).

6. The UE of claim 1, wherein the duration of the ISICS is less than the duration of executing the ICS.

7. The UE of claim 1, wherein the suitable cell is a cell that meets the cell selection criteria and is part of a list of selected public land mobile network (PLMN), registered PLMN, or equivalent PLMN.

8. The UE of claim 1, wherein the processor is further configured to put the UE into a sleep mode for a predetermined duration after executing the ICS.

9. The UE of claim 1, wherein the UE supports one or more Radio Access Technologies (RATs), wherein the one or more RATs include New Radio (NR), Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS), and Global System for Mobile Communications (GSM).

10. A method performed by a user equipment (UE), comprising: Determine whether the UE has lost service; In response to determining that the UE has lost service, an Initial Cell Selection (ICS) is initiated and an Intermediate Storage Information Cell Selection (ISICS) timer is started, wherein the ICS performs a search for multiple frequencies corresponding to multiple Radio Access Technologies (RATs), and wherein the duration of the ISICS timer is less than the time required to search for all of the multiple frequencies during the ICS. as well as In response to determining that no suitable cell was identified during the ICS and that the ISICS timer has expired, the ICS is paused and an ISICS is performed to identify a suitable cell, wherein during the pause of the ICS, the ISICS performs a search on a stored list of frequencies corresponding to a plurality of priority RATs, the plurality of priority RATs being a subset of the plurality of RATs.

11. The method of claim 10, further comprising: In response to the determination that no suitable cell was identified during the ISICS, the ICS is resumed and a timer is started.

12. The method of claim 10, further comprising: In response to determining that the UE has lost service, the Stored Information Cell Selection (SICS) is performed.

13. The method of claim 12, wherein the SICS includes performing a search on a stored list of frequencies associated with one or more previously used suitable cells.

14. The method of claim 10, wherein the ISICS includes performing a search for a plurality of frequencies corresponding to the last connected radio access technology (RAT) and the last registered public land mobile network (PLMN).

15. A non-transitory computer-readable medium (CRM) storing instructions, said instructions causing the processor to perform operations when executed by a processor of a user equipment (UE), said operations including: In response to determining that the UE has lost service, an Initial Cell Selection (ICS) is initiated and an Intermediate Storage Information Cell Selection (ISICS) timer is started, wherein the ICS performs a search for multiple frequencies corresponding to multiple Radio Access Technologies (RATs), and wherein the duration of the ISICS timer is less than the time required to search for all of the multiple frequencies during the ICS. as well as In response to determining that no suitable cell was identified during the ICS and that the ISICS timer has expired, the ICS is paused and an ISICS is performed to identify a suitable cell, wherein during the pause of the ICS, the ISICS performs a search on a stored list of frequencies corresponding to a plurality of priority RATs, the plurality of priority RATs being a subset of the plurality of RATs.

16. The non-transient CRM of claim 15, wherein the ISICS includes performing a search for a plurality of frequencies corresponding to the last connected radio access technology (RAT) and the last registered public land mobile network (PLMN).

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