User equipment (UE) parallel search in connected mode

Abstract

The invention relates to user equipment (UE) parallel search in connected mode. Methods, systems, and computer readable media are disclosed for performing operations including: receiving, by an access stratum (AS) layer of a user equipment (UE), a public land mobile network (PLMN) search request from a non-access stratum (NAS) layer of the UE; determining, by the AS layer, that the first connection instance is in a radio resource control (RRC) connection mode; responsively determining, by the AS layer, whether a second connection instance is available; and in response to determining that the second connection instance is available, triggering, by the AS layer, a PLMN search on the second connection instance, where the PLMN search includes one or more frequency scans.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 532,843, filed on August 15, 2023, which is incorporated herein by reference in its entirety. Background Art

[0003] Wireless communication networks provide integrated communication platforms and telecommunication services to wireless user devices. Example telecommunication services include telephone, data (e.g., voice, audio and / or video data), messaging and / or other services. Wireless communication networks have wireless access nodes that exchange wireless signals with wireless user devices using wireless network protocols (such as protocols described in various telecommunication standards promulgated by the Third Generation Partnership Project (3GPP)). Example wireless communication networks include time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal frequency division multiple access (OFDMA) networks, long term evolution (LTE) and fifth generation new radio (5G NR). Wireless communication networks use technologies such as OFDM, multiple input multiple output (MIMO), advanced channel coding, massive MIMO, beamforming and / or other features to facilitate mobile broadband services.

[0004] A Public Land Mobile Network (PLMN) refers to a network provided by an operator in a specific geographic area. A user equipment (UE) may perform a PLMN search when the UE is turned on or when it moves to a new location. A PLMN search may be automatically triggered by the UE or may be manually triggered, for example, in response to user input. During a PLMN search, the UE signals nearby base stations to identify accessible networks. In particular, the UE may "scan" frequency bands by transmitting signals on those frequency bands to determine the PLMNs available on those frequency bands.

[0005] In certain search processes, the frequency scan is divided into a short list search (SLS) scan (also known as a stored list search), a derived band search (DBS) scan, a DBS_MCC scan, and a remaining band search (RBS) scan. The SLS scan may include the most recently used frequencies stored in the UE. The SLS scan may have a shorter duration than the DBS scan and may therefore be performed at a faster rate. The DBS scan may be performed on a frequency band corresponding to the SLS frequency. The DBS scan may have a shorter duration than the RBS scan. In the DBS_MCC scan, the UE searches for the remainder of the country, the mobile country code (MCC), that was not searched in the DBS scan. The DBS_MCC scan is always scheduled after the DBS scan. The RBS scan may be performed every "x" DBS scans or when no suitable cell is found using the SLS scan or the DBS scan. The RBS scan may include all remaining frequencies of all frequency bands of a specific RAT. Summary of the invention

[0006] In an example implementation, a method to be performed by a user equipment (UE) involves: receiving, by an access stratum (AS) layer of the UE, a public land mobile network (PLMN) search request from a non-access stratum (NAS) layer of the UE; determining, by the AS layer, that a first connection instance is in a radio resource control (RRC) connection mode; responsively determining, by the AS layer, whether a second connection instance is available; and in response to determining that the second connection instance is available, triggering, by the AS layer, a PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0007] In aspects combinable with this example implementation, the one or more frequency scans include at least one of a short list search (SLS) scan, a derived band search (DBS) scan, or a residual band search (RBS) scan.

[0008] In another aspect that can be combined with any one of the preceding aspects, the method also includes: the AS layer uses the second connection instance to perform the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and the AS layer provides the NAS layer with a first set of PLMN search results detected on the available frequency band.

[0009] In another aspect that can be combined with any one of the preceding aspects, the method also includes: determining, by the AS layer, that the first connection instance has been switched to RRC idle mode; responsively, by the AS layer, performing the PLMN search on the remaining frequency band set using the first connection instance or the second connection instance; and providing, by the AS layer, to the NAS layer, a second set of PLMN search results detected on the remaining frequency band set.

[0010] In another aspect that can be combined with any of the preceding aspects, the method also includes: determining, by the AS layer, that the first connection instance has been transitioned to RRC idle mode during the PLMN search; and responsively triggering, by the AS layer, at least one remaining frequency scan using the first connection instance.

[0011] In another aspect which may be combined with any of the preceding aspects, the method further comprises: detecting, by the AS layer, activity on the second connection instance different from the PLMN search; and responsively terminating the PLMN search on the second connection instance.

[0012] In another aspect that may be combined with any of the preceding aspects, the method further includes: transmitting, by the AS layer to the NAS layer, a message comprising: (i) an indication of a frequency band searched before terminating the PLMN search, and (ii) a list of PLMNs identified on the searched frequency band.

[0013] In another aspect which may be combined with any of the preceding aspects, the method further comprises: resuming the PLMN search on the first connection instance.

[0014] In another aspect which may be combined with any of the preceding aspects, the first connection instance is for a first radio access technology (RAT) and the second connection instance is for a second RAT.

[0015] In another aspect which may be combined with any of the preceding aspects, the UE is a Multiple Subscriber Identity Module (MSIM) UE.

[0016] In another aspect which may be combined with any of the preceding aspects, the first connection instance is provided by a first SIM and the second connection instance is provided by a second SIM.

[0017] In another example implementation, a method to be performed by a user equipment (UE) involves: determining to perform a public land mobile network (PLMN) search on a first connection instance; determining that the first connection instance is in a radio resource control (RRC) connection mode; determining whether a second connection instance is available for the PLMN search; and in response to determining that the second connection instance is available, performing the PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0018] In one aspect that may be combined with this example implementation, the method further involves: performing the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and identifying a first subset of PLMN search results detected on the available frequency band.

[0019] In another aspect that can be combined with any of the preceding aspects, the method also includes: determining that the first connection instance is in RRC idle mode; responsively using the first connection instance or the second connection instance to perform the PLMN search on the remaining frequency band set; and identifying a second subset of PLMN search results detected on the remaining frequency band set.

[0020] In another aspect which may be combined with any of the preceding aspects, the method further comprises: determining that the first connection instance is in RRC idle mode; and responsively performing at least one remaining frequency scan on the first connection instance.

[0021] In another aspect which may be combined with any of the preceding aspects, the method further comprises: determining that the second connection instance is unavailable for the PLMN search; and responsively aborting the PLMN search on the second connection instance.

[0022] In another aspect which may be combined with any of the preceding aspects, the method further comprises identifying a PLMN found on the searched frequency band before aborting the PLMN search.

[0023] In another aspect which may be combined with any of the preceding aspects, the method further comprises: resuming the PLMN search on the first connection instance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A wireless network according to some implementations is illustrated.

[0025] Figure 2 An example protocol stack according to some specific implementations is illustrated.

[0026] Figure 3A and Figure 3B An example scenario of triggering a PLMN search when the UE is in RRC connected mode according to some implementations is illustrated.

[0027] Figure 4A , Figure 4B and Figure 4C A scenario of UE parallel search when in connected mode according to some specific implementations is illustrated.

[0028] Figure 5A Flowcharts illustrating example methods according to some implementations are shown.

[0029] Figure 5B A flow chart illustrating another example method according to some implementations is shown.

[0030] Figure 6An example user equipment (UE) according to some implementations is illustrated.

[0031] Figure 7 Example access nodes according to some implementations are illustrated. DETAILED DESCRIPTION

[0032] In existing wireless communication systems, when a manual or automatic public land mobile network (PLMN) search (e.g., a high priority PLMN search) is triggered while a user equipment (UE) is in a radio resource control (RRC) connected mode, the search is rejected or suspended until the RRC connection is released (e.g., the RRC connection moves to idle). This rejection may cause unnecessary delays, and in the worst case, the UE may not perform the search at all.

[0033] With the introduction of Multiple Subscriber Identity Module (MSIM) and Dual Receive Dual SIM Dual Standby (DR-DSDS), a UE can support connections to multiple access nodes. The multiple access nodes can have the same or different radio access technologies (RATs), such as Bluetooth. TM , Wi-Fi, Long Term Evolution (LTE), New Radio (NR). Under MSIM and DR-DSDS, the UE may include multiple connection instances, for example in the access stratum (AS) layer and the non-access stratum (NAS) layer, which allows the UE to support connections to multiple access nodes. In some examples, each connection instance is facilitated using a corresponding user identity module (SIM). In these examples, each connection instance is referred to as a SIM instance. In the AS layer, each connection instance may be connected to a different access node. For example, in the context of DR-DSDS, the UE may have two connection instances, for example, a first connection instance for connecting to an NR RAT and a second connection instance for connecting to an LTE RAT.

[0034] The present disclosure describes a system and method for a UE to perform parallel searches in connected mode. In order to perform parallel searches in connected mode, the UE may utilize MSIM and DR-DSDS features to perform a PLMN search while in RRC connected mode. In one embodiment, when the UE is in RRC connected mode in a current connection instance, the UE may use another connection instance to perform a PLMN search. To this end, in the AS layer, when the current connection instance is unavailable, the UE uses an available connection instance to perform a PLMN search. By performing a search using a second connection instance when the first connection instance is unavailable, the UE avoids search delays or failures that occur in existing devices when attempting a PLMN search while in RRC connected mode.

[0035] Figure 1A wireless network 100 is shown according to some implementations. The wireless network 100 includes UEs 102 and base stations 104 connected via one or more channels 106A, 106B across an air interface 108. The UEs 102 and base stations 104 communicate using a system that supports control for managing access of the UEs 102 via the base stations 104 to the network.

[0036] In some embodiments, the wireless network 100 is a standalone (SA) network in combination with a fifth generation (5G) new radio (NR) communication standard as defined by the third generation partnership project (3GPP) technical specification. In other embodiments, the wireless network 100 is a non-standalone (NSA) network in combination with long term evolution (LTE) and 5G NR communication standards. For example, the wireless network 100 can be an E-UTRA (Evolved Universal Terrestrial Radio Access)-NR dual connection (EN-DC) network or an NR-E-UTRA dual connection (NE-DC) network. In addition, other types of communication standards are possible, including future 3GPP systems (e.g., the sixth generation (6G)), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 technology, and the like. Although various aspects may be described herein using terms commonly associated with 5G NR, various aspects of the present disclosure may be applied to other systems, such as systems after 5G.

[0037] In the wireless network 100, the UE 102 and any other UE in the system may be, for example, any of a laptop computer, a smart phone, a tablet computer, a machine type device (such as a smart meter or a dedicated device for healthcare), an intelligent transportation system, or any other wireless device. In the wireless network 100, the base station 104 provides a network connection to the UE 102 to a wider network (not shown). The UE 102 connection is provided via an air interface 108 in a base station service area provided by the base station 104. In some specific implementations, this wider network may be a wide area network operated by a cellular network provider, or may be the Internet. Each base station service area associated with the base station 104 is supported by one or more antennas integrated with the base station 104. The service area may be divided into several sectors associated with one or more specific antennas. Such sectors may be physically associated with one or more fixed antennas, or may be assigned to a physical area with one or more tunable antennas or antenna settings, which may be adjusted in a beamforming process for directing signals to a specific sector.

[0038] UE 102 includes control circuitry 110 coupled to transmit circuitry 112 and receive circuitry 114. Transmit circuitry 112 and receive circuitry 114 may each be coupled to one or more antennas. Control circuitry 110 may include various combinations of dedicated circuitry and baseband circuitry. Transmit circuitry 112 and receive circuitry 114 may be adapted to transmit and receive data, respectively, and may include radio frequency (RF) circuitry and / or front end module (FEM) circuitry.

[0039] In various implementations, aspects of the transmit circuit 112, receive circuit 114, and control circuit 110 may be integrated in various ways to implement the operations described herein. The control circuit 110 may be adapted or configured to perform various operations, such as various operations related to the UE described elsewhere in this disclosure.

[0040] The transmission circuit 112 may perform various operations described in this specification. Additionally, the transmission circuit 112 may use multiple multiplexed uplink physical channels for transmission. The multiple uplink physical channels may be multiplexed, for example, according to time division multiplexing (TDM) or frequency division multiplexing (FDM) and carrier aggregation. The transmission circuit 112 may be configured to receive block data from the control circuit 110 to be transmitted across the air interface 108.

[0041] The receiving circuit 114 may perform various operations described in this specification. In addition, the receiving circuit 114 may receive a plurality of multiplexed downlink physical channels from the air interface 108 and relay these physical channels to the control circuit 110. The plurality of downlink physical channels may be multiplexed, for example, according to TDM or FDM and carrier aggregation. The transmitting circuit 112 and the receiving circuit 114 may respectively transmit and receive control data and content data (e.g., messages, images, videos, etc.) structured within data blocks carried by the physical channels.

[0042] Figure 1 A base station 104 is also shown. In some implementations, the base station 104 may be a 5G radio access network (RAN) or a next-generation RAN, an E-UTRAN, a non-terrestrial cell, or a traditional RAN such as a UTRAN. As used herein, the term "5G RAN" or the like may refer to a base station 104 operating in an NR or 5G wireless network 100, and the term "E-UTRAN" or the like may refer to a base station 104 operating in an LTE or 4G wireless network 100. The UE 102 utilizes connections (or channels) 106A, 106B, each connection comprising a physical communication interface or layer.

[0043] The base station 104 circuitry may include control circuitry 116 coupled to transmit circuitry 118 and receive circuitry 120. The transmit circuitry 118 and receive circuitry 120 may each be coupled to one or more antennas that may be used to enable communications via the air interface 108. The transmit circuitry 118 and receive circuitry 120 may be adapted to transmit and receive data, respectively, to any UE connected to the base station 104. The receive circuitry 120 may receive a plurality of uplink physical channels from one or more UEs including the UE 102.

[0044] exist Figure 1 In the figure, one or more channels 106A, 106B are shown as air interfaces to achieve communication coupling, and may comply with cellular communication protocols, such as 3GPP LTE protocol, advanced long term evolution (LTE-A) protocol, LTE-based unlicensed spectrum access (LTE-U), 5G protocol, NR protocol, NR-based unlicensed spectrum access (NR-U) protocol and / or any other communication protocol. In a specific implementation, UE 102 may directly exchange communication data via the ProSe interface. The ProSe interface may alternatively be referred to as a sidelink (SL) interface and may include one or more logical channels, including but not limited to a physical sidelink control channel (PSCCH), a physical sidelink discovery channel (PSDCH), and a physical sidelink broadcast channel (PSBCH).

[0045] Figure 2 An example protocol stack 200 according to some specific implementations is illustrated. The protocol stack 200 may be implemented by a UE such as UE 102. Figure 2 As shown, the protocol stack 200 may include a transport (TCP) layer 202, an IP layer 204, a non-access stratum (NAS) layer 206, an access stratum (AS) layer 208, and other layers. The NAS layer 206 may include an access point (AP) manager 210 and a mobility manager (MM) 212. In addition, the AP manager 210 is responsible for initiating a PLMN search (e.g., automatically or in response to user input). In addition, each MM 212 is responsible for mobility-related actions for a UE on a specific connection instance, such as PLMN selection. Specifically, the first MM is responsible for mobility-related actions for the first connection instance, the second MM is responsible for mobility-related actions for the second connection instance, and so on. Note that different MMs may be numbered. For example, the first MM may be labeled "MM0", the second MM may be labeled "MM1", and so on.

[0046] like Figure 2As also shown in the figure, the AS layer 208 includes an access layer manager 214, which is responsible for managing the RRC protocols (XRRC 216) for different connection instances, etc. For example, the RRC layer for the first connection instance, referred to as NR RRC (NRRC), can be used to connect to an NR access node, and the RRC layer for the second connection instance, referred to as LTE RRC (LRRC), can be used to connect to an LTE access node. Note that different connection instances can be numbered. For example, the RRC layer of the first connection instance can be represented as XRRC0, the RRC layer of the second connection instance can be represented as XRRC1, and so on. In the present disclosure, a connection instance associated with a specific radio access technology (RAT) is referred to as a connection instance of the RAT. In addition, the corresponding layers and / or protocols associated with a specific connection instance are numbered with the same number as the connection instance. For example, MM0 and XRRC0 are both associated with a first connection instance (e.g., SIM instance 0).

[0047] Consistent with the above discussion, when a PLMN search is triggered in an existing UE while the UE is in RRC connected mode (e.g., for communicating packet switched (PS) data), the search is rejected or suspended until the existing RRC connection is released. This rejection or suspension may cause unnecessary delays, and in the worst case, the PLMN search may not be performed at all.

[0048] Figure 3A and Figure 3B Example scenarios of triggering PLMN search when the UE is in RRC connected mode according to some specific implementations are illustrated. The entities involved in these scenarios include AP manager 302 (NAS layer), MM 304 (NAS layer), ASM 306 (AS layer). The RRC layer (AS layer) is represented as XRRC0.

[0049] by Figure 3A300, the UE is in RRC connected mode, as shown in block 308. While in RRC connected mode, MM 304 receives a PLMN list request 310 from AP manager 302. In response to receiving the request, MM 304 initiates a PLMN protection timer 312, which acts as an upper time threshold for attempting a PLMN search. MM 304 then transmits a PLMN request 314 to ASM 306. ASM 306 forwards PLMN request 316 to XRRC0. Because XRRC0 is in RRC connected mode, XRRC0 responds with a PLMN search suspend message 318. In response to receiving the PLMN search suspend message 318, ASM 306 transmits a PLMN suspend message 320 to MM0. MM0 then initiates an abort procedure 322. PLMN protection timer 312 then expires at 324 without performing a PLMN search. Because the PLMN protection timer 312 expires without performing a PLMN search, the MM 304 transmits a PLMN list reject message 326 to the AP manager 302 .

[0050] Go to Figure 3B In the scenario 340, the AP manager 302 initiates a PLMN search before the UE is in RRC connected mode. After initiating the PLMN search, in step 342, an SLS scan is performed and the results are provided to the AP manager 302. Then, a DBS scan is initiated in step 344. However, before the DBS scan is completed, the UE moves to RRC connected mode. Therefore, the DBS search is suspended and the PLMN search is aborted, as shown in message 346. The MM 304 provides a partial list 348 of PLMN search results (e.g., from the SLS scan and / or the partial DBS scan) to the AP manager 302.

[0051] As illustrated by these scenarios, when a PLMN search is triggered or performed while the UE is in RRC connected mode, the search is rejected or suspended until the existing RRC connection is released. The present disclosure describes systems and methods that enable a UE to perform parallel searches in connected mode, particularly in scenarios where the UE has more than one connected instance (e.g., more than one SIM instance facilitated by multiple SIMs).

[0052] In some specific implementations, when a PLMN search is triggered while the UE is in RRC connected mode in a first connection instance, the UE is configured to initiate a PLMN search using a second connection instance. More specifically, when a PLMN search is triggered while the first instance is in RRC connected mode, the UE is configured to perform a PLMN search using a radio frequency (RF) resource allocation of the second instance. The RF allocation of the second instance may be different from the RF allocation of the first instance. When the UE detects that a PLMN search is triggered on a first connection instance in RRC connected mode, the UE is configured to trigger a PLMN search on a second connection instance that has no ongoing activity (e.g., in RRC idle mode). The second connection instance then provides the results of the PLMN search to the first connection instance for further processing (e.g., MM0). However, if the second connection instance has ongoing activity, the UE is configured to perform a search using the first connection instance (or possibly another connection instance) based on an opportunity.

[0053] In some specific implementations, the ASM is configured to monitor a PLMN search triggered on the current connection instance. In particular, the AP manager transmits a PLMN search request to the MM (e.g., MM0) of the current connection instance, which in turn transmits a request to the ASM. In response to determining that the PLMN search has been triggered, the ASM checks the connection status of the current instance (e.g., XRRC0). If the current instance is in RRC idle mode, the ASM triggers a PLMN search on the current connection instance. Conversely, if the current connection instance is in RRC connection mode, the ASM is configured to check the status of a second connection instance. If there is no ongoing process on XRRC1 (e.g., the connection instance is in RRC idle mode or there is no ongoing activity, etc.), the ASM is configured to trigger a PLMN search on XRRC1.

[0054] In some implementations, once a PLMN search is triggered on XRRC1, the UE uses XRRC1 to perform a frequency scan. In particular, the UE scans the frequency bands allocated by the RF of XRRC1. Once XRRC1 performs the frequency scan, XRRC1 reports the results to the ASM, which in turn reports the results to the first connection instance, such as MM0. MM0 then provides a list of PLMN search results to the AP manager.

[0055] Although the UE can scan the frequency bands of the RF allocation of XRRC1, the UE cannot scan the frequency bands of the RF allocation of XRRC0 because the RF allocation is currently in use. For such frequency bands, XRRC1 returns an incomplete PLMN list to the ASM. Later, once XRRC0 stops using these frequency bands, the ASM can instruct XRRC0 or XRRC1 to scan these frequency bands.

[0056] In some implementations, if XRRC0 switches to RRC idle mode while XRRC1 is still performing a PLMN search, the ASM is configured to trigger the remaining unfinished frequency scans on XRRC0. Specifically, once XRRC1 reports the results of the current frequency scan, the ASM instructs XRRC0 to perform the remaining frequency scans (if any) not performed by XRRC1.

[0057] In some implementations, if a request is triggered while XRRC1 is performing a PLMN search, the ASM is configured to instruct XRRC1 to abort the PLMN search. The ASM then reports to MM0 the searched frequency bands and the PLMNs that have been found. The ASM then falls back to conventional behavior (e.g., performing a PLMN search using XRRC0 once the ongoing process is completed).

[0058] Note that in existing systems, if the first connection instance (XRRC0) is in PS connection mode and a manual PLMN search is initiated on the second connection instance (XRRC1), the ASM suspends data on XRRC0 because the manual PLMN search has a higher priority. The ASM then causes the UE to transition to a single receive dual SIM dual standby (SR-DSDS) operation mode instead of DR-DSDS. Note that SR-DSDS is a more restricted operation mode than DR-DSDS.

[0059] In some implementations, as part of the disclosed methods and systems, when a manual PLMN is triggered on the second connection instance, the ASM is configured to perform an exception to the existing configuration. Therefore, the UE can continue to operate in DR-DSDS mode.

[0060] Figure 4A , Figure 4B and Figure 4C Scenarios of parallel search of UEs in connected mode according to some specific implementations, such as scenario 400, scenario 420, and scenario 440, are illustrated. Sequence diagrams are used to describe these scenarios. The actions in these scenarios can be performed by a protocol stack of the UE, which includes: an AP manager 402, a first MM 404 (also referred to as MM0) for a first connection instance, a second MM 406 (also referred to as MM1) for a second connection instance, and an ASM 408. The RRC layer of the first connection instance is represented as XRRC0, and the RRC layer of the second connection instance is represented as XRRC1. The first connection instance can be connected to a first RAT (e.g., NR RAT), and the second connection instance can be connected to a second RAT (e.g., LTE RAT). Alternatively, different connections can be connected to access nodes of the same RAT.

[0061] In the following scenario, the frequency scan for PLMN search is performed in the following order: SLS scan, DBS scan, DBS_MCC scan and RBS scan. A different order of frequency scan is also possible.

[0062] Steering Figure 4A , scenario 400 involves the AP manager 402 determining to perform a PLMN search in a first connection instance. The AP manager 402 transmits a PLMN search request to MM0. In response to receiving the search request, MM0 starts a PLMN protection timer. Then, MM0 transmits a request to ASM 408 to perform an SLS scan in conjunction with the PLMN search. In response to receiving the request, ASM 408 determines the status of the current connection instance (first connection instance). In this scenario, the current instance is in RRC connection mode. In response to determining that the current instance is in RRC connection mode, ASM 408 checks the status of a second connection instance. If there is no ongoing process on the second connection instance, ASM 408 triggers a PLMN search on the second connection instance XRRC1.

[0063] More specifically, ASM 408 performs SLS scan, DBS scan, DBS_MCC scan and RBS scan. Figure 4A As shown, the results of the DBS_MCC scan and the RBS scan are incomplete. This is because these scans involve scanning the frequency band on which XRRC0 is operating. Therefore, as shown in boxes 410 and 412, the results of the DBS_MCC scan and the RBS scan are marked as incomplete. In particular, the DBS_MCC scan and the RBS scan are performed on a non-conflicting dual reception (NCDR) band. In the case of dual SIM, when one SIM instance is performing any action (e.g., PS data TX-RX in one scenario), the other SIM instance is allowed to perform scans only on non-conflicting bands to avoid TX-RX, RX-RX conflict scenarios. As shown in messages 414 and 416, the results of the DBS scan and the RBS scan include the NCDR band.

[0064] like Figure 4A As shown, the result of the DBS_MCC scan includes a "No allowed band" message 418. In the case where the AS cannot perform a scan on some bands supported by the UE due to NCDR restrictions, the AS provides the reason for no allowed bands using the searched band information and the found PLMN (if any).

[0065] At some point, operations on XRRC0 cease, for example, by XRRC0 moving to RRC idle mode. In response, MM0 provides a request to ASM 408 to complete previously uncompleted scans, for example, DBS_MCC scans and RBS scans. ASM 408 instructs XRRC0 or XRRC1 to complete the scans. In scenario 400, ASM 408 instructs XRRC0 to perform uncompleted scans. Thus, Figure 4A As shown, XRRC0 is used to perform DBS_MCC scanning and RBS scanning.

[0066] Move to Figure 4B As in scenario 400, in response to determining that XRRC0 has ongoing activity and XRRC1 has no ongoing activity, the UE in scenario 420 performs a PLMN search using XRRC1. However, in scenario 420, after XRRC1 performs one or more scans, a request is triggered on a second connection instance. As shown in box 422, MM1 transmits a message related to the new request to ASM 408. As shown in the same box, in response to receiving the message, ASM 408 terminates the PLMN search performed on XRRC1. ASM 408 transmits a message to MM0 indicating that the latest scan is incomplete. In turn, MM0 provides incomplete PLMN results (e.g., a list of PLMNs that have been found) to AP manager 402. In addition, ASM 408 transmits a message to XRRC1 to perform an action related to the new request.

[0067] Later, MM0 transmits a request to perform one or more searches that were not previously completed to ASM 408. Upon receiving the request, ASM 408 falls back to the traditional process, for example, performing the search on XRRC0.

[0068] Go to Figure 4C , as in scenarios 400 and 420, in response to determining that XRRC0 has ongoing activity and XRRC1 has no ongoing activity, the UE in scenario 440 performs a PLMN search using XRRC1. In this scenario, XRRC1 performs an SLS scan and a DBS scan. During or after the DBS scan is completed, the first connection instance moves to RRC idle mode, as shown in box 442. ASM 408 detects that the first connection instance has moved to RRC idle mode. In response, ASM 408 instructs XRRC0 to perform the remaining scans. In scenario 440, the remaining scans include DBS_MCC and RBS. Therefore, ASM 408 instructs XRRC0 to perform these scans, as shown in box 442.

[0069] Figure 5AA flowchart of an example method 500 according to some specific implementations is illustrated. For clarity of presentation, the following description generally describes the method 500 in the context of other figures in this specification. For example, the method 500 may be performed by Figure 1 UE 102 of the present invention is executed. UE 102 may be an MSIM UE. It should be understood that method 500 may be executed by any suitable system, environment, software, hardware, or a combination of systems, environments, software, and hardware, as appropriate. In some specific implementations, the steps of method 500 may be executed in parallel, in combination, in a loop, or in any order.

[0070] At step 502, method 500 involves receiving, by an access stratum (AS) layer of the UE, a public land mobile network (PLMN) search request from a non-access stratum (NAS) layer of the UE.

[0071] At step 504 , the method 500 involves: determining, by the AS layer, that the first connection instance is in a radio resource control (RRC) connected mode.

[0072] At step 506 , method 500 involves: responsively determining, by the AS layer, whether the second connection instance is available.

[0073] In step 508 , in response to determining that the second connection instance is available, the method 500 triggers, by the AS layer, a PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0074] In some implementations, the one or more frequency scans include at least one of a short list search (SLS) scan, a derived band search (DBS) scan, or a residual band search (RBS) scan.

[0075] In some specific implementations, the method also involves: the AS layer uses the second connection instance to perform the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and the AS layer provides the NAS layer with a first set of PLMN search results detected on the available frequency band.

[0076] In some specific implementations, the method also involves: the AS layer determines that the first connection instance has been switched to RRC idle mode; the AS layer responsively uses the first connection instance or the second connection instance to perform the PLMN search on the remaining frequency band set; and the AS layer provides the NAS layer with a second set of PLMN search results detected on the remaining frequency band set.

[0077] In some specific implementations, the method further involves: determining, by the AS layer, that the first connection instance has been transitioned to RRC idle mode during the PLMN search; and responsively triggering, by the AS layer, at least one remaining frequency scan using the first connection instance.

[0078] In some specific implementations, the method further involves: detecting, by the AS layer, an activity on the second connection instance that is different from the PLMN search; and responsively terminating the PLMN search on the second connection instance.

[0079] In some specific implementations, the method further involves: transmitting, by the AS layer to the NAS layer, a message comprising: (i) an indication of a frequency band searched before terminating the PLMN search, and (ii) a list of PLMNs identified on the searched frequency band.

[0080] In some specific implementations, the method further involves: resuming the PLMN search on the first connection instance.

[0081] In some implementations, the first connection instance is for a first radio access technology (RAT) and the second connection instance is for a second RAT.

[0082] In some implementations, the UE is a Multiple Subscriber Identity Module (MSIM) UE.

[0083] In some implementations, the first connection instance is provided by a first SIM, and the second connection instance is provided by a second SIM.

[0084] Figure 5B A flowchart of an example method 510 according to some specific implementations is illustrated. For clarity of presentation, the following description generally describes the method 510 in the context of other figures in this specification. For example, the method 510 can be performed by Figure 1 UE 102 of the present invention may be executed. UE 102 may be an MSIM UE. It should be understood that method 510 may be executed by any suitable system, environment, software, hardware, or a combination of systems, environments, software, and hardware, as appropriate. In some specific implementations, the steps of method 510 may be executed in parallel, in combination, in a loop, or in any order.

[0085] At step 512, method 510 involves determining to perform a public land mobile network (PLMN) search on the first connection instance.

[0086] At step 514, method 510 involves determining that the first connection instance is in a radio resource control (RRC) connected mode.

[0087] At step 516, method 510 involves determining whether a second connection instance is available for the PLMN search.

[0088] At step 518 , method 510 involves: in response to determining that the second connection instance is available, performing the PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0089] In some specific implementations, the method further involves: performing the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and identifying a first subset of PLMN search results detected on the available frequency band.

[0090] In some specific implementations, the method also involves: determining that the first connection instance is in RRC idle mode; responsively using the first connection instance or the second connection instance to perform the PLMN search on the remaining frequency band set; and identifying a second subset of PLMN search results detected on the remaining frequency band set.

[0091] In some specific implementations, the method further involves: determining that the first connection instance is in RRC idle mode; and responsively performing at least one remaining frequency scan on the first connection instance.

[0092] In some specific implementations, the method further involves: determining that the second connection instance is not available for the PLMN search; and responsively terminating the PLMN search on the second connection instance.

[0093] In some implementations, the method further involves identifying a PLMN found on the searched frequency band before terminating the PLMN search.

[0094] In some specific implementations, the method further involves: resuming the PLMN search on the first connection instance.

[0095] In some implementations, the apparatus is a user equipment (UE) or a baseband processor.

[0096] Figure 6 An example UE 600 according to some implementations is illustrated. The UE 600 may be similar to Figure 1 UE 102 and is substantially interchangeable therewith.

[0097] UE 600 may be any mobile or non-mobile computing device, such as, for example, a mobile phone, a computer, a tablet computer, a wearable device (eg, a smart watch), a slack IoT device.

[0098] UE 600 may include a processor 602, an RF interface circuit 604, a memory / storage 606, a user interface 608, a sensor 610, a driver circuit 612, a power management integrated circuit (PMIC) 614, one or more antennas 616, and a battery 618. The components of UE 600 may be implemented as an integrated circuit (IC), a portion of an integrated circuit, a discrete electronic device or other module, logic component, hardware, software, firmware, or a combination thereof. Figure 6 The block diagram of UE 600 is intended to show a high-level view of certain of the components of UE 600. However, some of the components shown may be omitted, additional components may be present, and different arrangements of the components shown may occur in other implementations.

[0099] Components of UE 600 may be coupled to various other components via one or more interconnects 620, which may represent any type of interface, input / output, bus (local, system, or extension), transmission line, trace, optical connection, etc., which allows various circuit components (on a common or different chip or chipset) to interact with each other.

[0100] The processor 602 may include processor circuits such as a baseband processor circuit (BB) 622A, a central processor unit circuit (CPU) 622B, and a graphics processor unit circuit (GPU) 622C. The processor 602 may include any type of circuit or processor circuit that executes or otherwise operates computer-executable instructions (such as program codes, software modules, or functional processes from the memory / storage device 606) to cause the UE 600 to perform operations as described herein.

[0101] In some implementations, the baseband processor circuit 622A may access a communication protocol stack 624 in the memory / storage device 606 to communicate over a 3GPP compatible network. Generally speaking, the baseband processor circuit 622A may access the communication protocol stack to: perform user plane functions at the physical (PHY) layer, the medium access control (MAC) layer, the radio link control (RLC) layer, the packet data convergence protocol (PDCP) layer, the service data adaptation protocol (SDAP) layer, and the PDU layer; and perform control plane functions at the PHY layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer, and the non-access layer. In some implementations, the PHY layer operations may be additionally / alternatively performed by components of the RF interface circuit 604. The baseband processor circuit 622A may generate or process baseband signals or waveforms that carry information in a 3GPP compatible network. In some implementations, the waveform used for NR can be based on cyclic prefix orthogonal frequency division multiplexing (OFDM) "CP-OFDM" in uplink or downlink, and discrete Fourier transform spread OFDM "DFT-S-OFDM" in uplink.

[0102] The memory / storage 606 may include one or more non-transitory computer-readable media including instructions (e.g., the communication protocol stack 624) that may be executed by one or more of the processors 602 to cause the UE 600 to perform various operations described herein. The memory / storage 606 includes any type of volatile or non-volatile memory that may be distributed throughout the UE 600. In some implementations, some of the memory / storage 606 may be located on the processor 602 itself (e.g., L1 cache and L2 cache), while other memory / storage 606 are located external to the processor 602 but can be accessed via a memory interface. The memory / storage 606 may include any suitable volatile or non-volatile memory, such as, but not limited to, dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory, or any other type of memory device technology.

[0103] The RF interface circuit 604 may include a transceiver circuit and a radio frequency front end module (RFEM), which allows the UE 600 to communicate with other devices through a radio access network. The RF interface circuit 604 may include various elements arranged in a transmit path or a receive path. These elements may include, for example, switches, mixers, amplifiers, filters, synthesizer circuits, control circuits, etc.

[0104] In the receive path, the RFEM may receive the radiated signal from the air interface via antenna 616 and proceed to filter and amplify the signal (using a low noise amplifier). The signal may be provided to the transceiver's receiver, which down-converts the RF signal to a baseband signal provided to the baseband processor of processor 602.

[0105] In the transmit path, the transmitter of the transceiver up-converts the baseband signal received from the baseband processor and provides the RF signal to the RFEM. The RFEM may amplify the RF signal through a power amplifier before the signal is radiated across the air interface via the antenna 616. In various specific implementations, the RF interface circuit 604 may be configured to transmit / receive signals in a manner compatible with the NR access technology.

[0106] Antenna 616 may include one or more antenna elements to convert electrical signals into radio waves to travel through the air and convert received radio waves into electrical signals. These antenna elements may be arranged into one or more antenna panels. Antenna 616 may have an antenna panel that is omnidirectional, directional, or a combination thereof to achieve beamforming and multiple-input / multiple-output communications. Antenna 616 may include a microstrip antenna, a printed antenna made on the surface of one or more printed circuit boards, a patch antenna, a phased array antenna, etc. Antenna 616 may have one or more panels designed for a specific frequency band including a band in FR1 or FR2.

[0107] The user interface 608 includes various input / output (I / O) devices designed to enable a user to interact with the UE 600. The user interface 608 includes input device circuits and output device circuits. The input device circuit includes any physical or virtual components for accepting input, including in particular one or more physical or virtual buttons (e.g., reset button), physical keyboards, keypads, mice, touch pads, touch screens, microphones, scanners, headphones, etc. The output device circuit includes any physical or virtual components for displaying information or otherwise conveying information (such as sensor readings, actuator positions, or other similar information). The output device circuit may include any number or combination of audio or visual displays, including in particular one or more simple visual outputs / indicators (e.g., binary state indicators, such as light emitting diodes (LEDs)) and multi-character visual outputs, or more complex outputs, such as display devices or touch screens (e.g., liquid crystal displays "LCDs", LED displays, quantum dot displays, projectors, etc.), where the output of characters, graphics, multimedia objects, etc. is generated or produced by the operation of the UE 600.

[0108] Sensor 610 may include a device, module, or subsystem that is designed to detect events or changes in its environment and to communicate information about the detected events (sensor data) to some other device, module, subsystem, etc. Examples of such sensors include, among others: an inertial measurement unit including an accelerometer, gyroscope, or magnetometer; a microelectromechanical system or nanoelectromechanical system including a three-axis accelerometer, three-axis gyroscope, or magnetometer; a fluid level sensor; a temperature sensor (e.g., a thermistor); a pressure sensor; an image capture device (e.g., a camera or a lensless aperture); a light detection and ranging sensor; a proximity sensor (e.g., an infrared radiation detector, etc.); a depth sensor; an ambient light sensor; an ultrasonic transceiver; a microphone or other similar audio capture device; and the like.

[0109] The driver circuit 612 may include software and hardware elements that operate to control specific devices embedded in, attached to, or otherwise communicatively coupled to the UE 600. The driver circuit 612 may include separate drivers to allow other components to interact with or control various input / output (I / O) devices that may be present in or connected to the UE 600. For example, the driver circuit 612 may include: a display driver for controlling and allowing access to a display device, a touch screen driver for controlling and allowing access to a touch screen interface, a sensor driver for obtaining sensor readings of the sensor 610 and controlling and allowing access to the sensor 610, a driver for obtaining an actuator position of an electromechanical component or controlling and allowing access to an electromechanical component, a camera driver for controlling and allowing access to an embedded image capture device, and an audio driver for controlling and allowing access to one or more audio devices.

[0110] The PMIC 614 may manage the power provided to various components of the UE 600. In particular, with respect to the processor 602, the PMIC 614 may control power source selection, voltage scaling, battery charging, or DC to DC conversion.

[0111] In some implementations, the PMIC 614 may control or otherwise function as part of various power saving mechanisms of the UE 600. The battery 618 may power the UE 600, but in some examples, the UE 600 may be installed or deployed in a fixed location and may have a power source coupled to a power grid. The battery 618 may be a lithium-ion battery, a metal-air battery such as a zinc-air battery, an aluminum-air battery, a lithium-air battery, etc. In some implementations, such as in vehicle-based applications, the battery 618 may be a typical lead-acid automotive battery.

[0112] Figure 7 An example access node 700 (e.g., a base station or gNB) is illustrated according to some implementations. Access node 700 may be similar to base station 104 and substantially interchangeable therewith. Access node 700 may include a processor 702, RF interface circuitry 704, core network (CN) interface circuitry 706, memory / storage circuitry 708, and one or more antennas 710.

[0113] The components of access node 700 may be coupled to various other components via one or more interconnects 712. Processor 702, RF interface circuitry 704, memory / storage circuitry 708 (including communication protocol stack 714), antenna 710, and interconnects 712 may be similar to those of reference 700. Figure 6Like-named elements are shown and described.For example, processor 702 may include processor circuits such as, for example, baseband processor circuit (BB) 716A, central processor unit circuit (CPU) 716B, and graphics processor unit circuit (GPU) 716C.

[0114] The CN interface circuit 706 may provide connectivity to a core network (e.g., a 5GC using a 5th Generation Core Network (5GC) compatible network interface protocol such as a Carrier Ethernet protocol or some other suitable protocol). Network connectivity may be provided to / from the access node 700 via optical fiber or wireless backhaul. The CN interface circuit 706 may include one or more dedicated processors or FPGAs for communicating using one or more of the aforementioned protocols. In some implementations, the CN interface circuit 706 may include multiple controllers for providing connectivity to other networks using the same or different protocols.

[0115] As used herein, the terms "access node", "access point", etc. may be described as equipment that provides radio baseband functionality for data and / or voice connections between a network and one or more users. These access nodes may be referred to as BS, gNB, RAN node, eNB, NodeB, RSU, TRxP or TRP, etc., and may include ground stations (e.g., terrestrial access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). As used herein, the terms "NG RAN node", etc. may refer to an access node 700 (e.g., a gNB) operating in an NR or 5G system, and the terms "E-UTRAN node", etc. may refer to an access node 700 (e.g., an eNB) operating in an LTE or 4G system. According to various specific implementations, the access node 700 may be implemented as one or more of a dedicated physical device such as a macrocell base station and / or a low power (LP) base station for providing a femtocell, picocell or other similar cell with a smaller coverage area, smaller user capacity or higher bandwidth than a macrocell.

[0116] In some implementations, all or part of the access node 700 may be implemented as one or more software entities running on a server computer as part of a virtual network that may be referred to as a CRAN and / or a virtual baseband unit pool (vBBUP). In a V2X scenario, the access node 700 may be or act as a "road side unit". The term "road side unit" or "RSU" may refer to any traffic infrastructure entity used for V2X communications. The RSU may be implemented in or by a suitable RAN node or a stationed (or relatively stationed) UE, where an RSU implemented in or by a UE may be referred to as a "UE-type RSU", an RSU implemented in or by an eNB may be referred to as an "eNB-type RSU", an RSU implemented in or by a gNB may be referred to as a "gNB-type RSU", and so on.

[0117] For ease of description, various components may be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to". Representing a component configured to perform one or more tasks expressly intends that the component does not invoke the interpretation of 35 U.S.C. §112(f).

[0118] Embodiment 1 is a user equipment (UE), which includes: one or more processors; and a memory, wherein the memory stores instructions, which, when executed by the one or more processors, cause the UE to perform operations including the following items: receiving, by an access stratum (AS) layer of the UE, a public land mobile network (PLMN) search request from a non-access stratum (NAS) layer of the UE; determining, by the AS layer, that a first connection instance is in a radio resource control (RRC) connection mode; responsively determining, by the AS layer, whether a second connection instance is available; and in response to determining that the second connection instance is available, triggering, by the AS layer, a PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0119] Embodiment 2 is the UE of embodiment 1, wherein the one or more frequency scans include at least one of a short list search (SLS) scan, a derived band search (DBS) scan, or a residual band search (RBS) scan.

[0120] Embodiment 3 is the UE described in Embodiment 1, and the operation further includes: the AS layer uses the second connection instance to perform the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and the AS layer provides the NAS layer with a first set of PLMN search results detected on the available frequency band.

[0121] Embodiment 4 is the UE described in Embodiment 3, and the operation further includes: determining, by the AS layer, that the first connection instance has been converted to RRC idle mode; responsively, by the AS layer, using the first connection instance or the second connection instance to perform the PLMN search on the remaining frequency band set; and providing, by the AS layer, to the NAS layer, a second set of PLMN search results detected on the remaining frequency band set.

[0122] Embodiment 5 is the UE described in Embodiment 1, and the operation further includes: determining by the AS layer during the PLMN search that the first connection instance has been converted to RRC idle mode; and responsively triggering by the AS layer at least one remaining frequency scan using the first connection instance.

[0123] Embodiment 6 is the UE described in Embodiment 1, and the operation further includes: detecting, by the AS layer, an activity on the second connection instance that is different from the PLMN search; and responsively terminating the PLMN search on the second connection instance.

[0124] Embodiment 7 is the UE described in Embodiment 6, and the operation further includes: the AS layer transmits a message to the NAS layer, the message including: (i) an indication of the frequency band searched before terminating the PLMN search, and (ii) a list of PLMNs identified on the searched frequency band.

[0125] Embodiment 8 is the UE described in Embodiment 6, and the operation further includes: resuming the PLMN search on the first connection instance.

[0126] Embodiment 9 is the UE of embodiment 1, wherein the first connection instance is for a first radio access technology (RAT), and the second connection instance is for a second RAT.

[0127] Embodiment 10 is the UE described in embodiment 1, wherein the UE is a multi-subscriber identity module (MSIM) UE.

[0128] Embodiment 11 is the UE described in embodiment 1, wherein the first connection instance is provided by a first SIM, and the second connection instance is provided by a second SIM.

[0129] Embodiment 12 is a device comprising: a processing circuit configured to perform operations including: determining to perform a public land mobile network (PLMN) search on a first connection instance; determining that the first connection instance is in a radio resource control (RRC) connection mode; determining whether a second connection instance is available for the PLMN search; and in response to determining that the second connection instance is available, performing the PLMN search on the second connection instance, wherein the PLMN search includes one or more frequency scans.

[0130] Embodiment 13 is the apparatus described in Embodiment 12, wherein the operation further includes: performing the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not have a frequency band conflict with the first connection instance; and identifying a first subset of PLMN search results detected on the available frequency band.

[0131] Embodiment 14 is the apparatus described in embodiment 12, wherein the operation further includes: determining that the first connection instance is in RRC idle mode; responsively performing the PLMN search on the remaining frequency band set using the first connection instance or the second connection instance; and identifying a second subset of PLMN search results detected on the remaining frequency band set.

[0132] Embodiment 15 is the apparatus of embodiment 12, wherein the operation further comprises: determining that the first connection instance is in RRC idle mode; and responsively performing at least one remaining frequency scan on the first connection instance.

[0133] Embodiment 16 is the apparatus of embodiment 12, wherein the operation further comprises: determining that the second connection instance is not available for the PLMN search; and responsively terminating the PLMN search on the second connection instance.

[0134] Embodiment 17 is the apparatus of embodiment 16, wherein the operation further comprises: identifying a PLMN found on the searched frequency band before terminating the PLMN search.

[0135] Embodiment 18 is the apparatus described in Embodiment 16, wherein the operation further includes: resuming the PLMN search on the first connection instance.

[0136] Embodiment 19 is the apparatus of embodiment 12, wherein the apparatus is a user equipment (UE) or a baseband processor.

[0137] Embodiment 20 may include one or more non-transitory computer-readable media, which include instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform operations described in or related to any one of Embodiments 1 to 19 or one or more elements of any other method or process described herein.

[0138] Embodiment 21 may include a device comprising logical components, modules and / or circuits (e.g., processing circuits) for performing one or more elements of operations described in or related to any of Embodiments 1 to 19 or any other method or process described herein.

[0139] Example 22 may include methods, techniques or processes described or related to any one of Examples 1 to 19, or parts or components thereof.

[0140] Embodiment 23 may include a device comprising: one or more processors and one or more computer-readable media, wherein the one or more computer-readable media include instructions that, when executed by the one or more processors, cause the one or more processors to perform operations, techniques, or processes, or portions thereof, described in or related to any one of Embodiments 1 to 19.

[0141] Embodiment 24 may include a method of communicating in a wireless network as shown and described herein.

[0142] Embodiment 25 may include a system for providing wireless communications as shown and described herein.

[0143] Embodiment 26 may include an apparatus for providing wireless communication as shown and described herein. The operations or actions performed by the apparatus may include operations according to any one of Embodiments 1 to 19.

[0144] Unless explicitly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. Modifications and variations are possible in view of the above teachings or may be obtained from the practice of various embodiments.

[0145] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to include all such variations and modifications.

[0146] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

Claims

1. A user equipment UE, the UE comprising: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the UE to perform operations including: Receiving, by the access stratum AS layer of the UE, a public land mobile network PLMN search request from the non-access stratum NAS layer of the UE; The AS layer determines that the first connection instance is in a radio resource control RRC connection mode; Responsively determining, by the AS layer, whether the second connection instance is available; as well as In response to determining that the second connection instance is available, a PLMN search on the second connection instance is triggered by the AS layer, wherein the PLMN search includes one or more frequency scans.

2. The UE according to claim 1, wherein the one or more frequency scans comprise at least one of a short list search (SLS) scan, a derived band search (DBS) scan, or a remaining band search (RBS) scan.

3. The UE according to claim 1, wherein the operation further comprises: The AS layer uses the second connection instance to perform the PLMN search on an available frequency band that is not currently used by the first connection instance or does not conflict with the first connection instance; as well as The AS layer provides the NAS layer with a first set of PLMN search results detected on the available frequency band.

4. The UE according to claim 3, wherein the operation further comprises: Determining, by the AS layer, that the first connection instance has been switched to an RRC idle mode; The AS layer responsively uses the first connection instance or the second connection instance to perform the PLMN search on the remaining frequency band set; as well as A second set of PLMN search results detected on the remaining frequency band set is provided by the AS layer to the NAS layer.

5. The UE according to claim 1, wherein the operation further comprises: Determining, by the AS layer during the PLMN search, that the first connection instance has been transitioned to an RRC idle mode; as well as At least one remaining frequency scan using the first connection instance is responsively triggered by the AS layer.

6. The UE according to claim 1, wherein the operation further comprises: detecting, by the AS layer, an activity on the second connection instance different from the PLMN search; as well as Responsively terminating the PLMN search on the second connection instance.

7. The UE according to claim 6, the operation further comprising: A message is transmitted by the AS layer to the NAS layer, the message including: (i) an indication of a frequency band searched before terminating the PLMN search, and (ii) a list of PLMNs identified on the searched frequency band.

8. The UE according to claim 6, the operation further comprising: Resume the PLMN search on the first connection instance. 9 . The UE of claim 1 , wherein the first connection instance is for a first radio access technology (RAT) and the second connection instance is for a second RAT.

10. The UE of claim 1, wherein the UE is a Multiple Subscriber Identity Module (MSIM) UE.

11. The UE of claim 1, wherein the first connection instance is provided by a first SIM and the second connection instance is provided by a second SIM.

12. A device, comprising: A processing circuit configured to perform operations including: Determining to perform a public land mobile network PLMN search on the first connection instance; Determining that the first connection instance is in a radio resource control RRC connected mode; determining whether a second connection instance is available for the PLMN search; as well as In response to determining that the second connection instance is available, the PLMN search is performed on the second connection instance, wherein the PLMN search includes one or more frequency scans.

13. The apparatus of claim 12, wherein the operations further comprise: Performing the PLMN search on an available frequency band that is not currently used by the first connection instance or that does not conflict with the first connection instance; as well as A first subset of PLMN search results detected on the available frequency band is identified.

14. The apparatus of claim 12, wherein the operations further comprise: Determining that the first connection instance is in RRC idle mode; Responsively performing the PLMN search on a remaining set of frequency bands using the first connection instance or the second connection instance; as well as A second subset of PLMN search results detected on the remaining set of frequency bands is identified.

15. The apparatus of claim 12, wherein the operations further comprise: Determining that the first connection instance is in RRC idle mode; as well as Responsively, at least one remaining frequency scan is performed on the first connection instance.

16. The apparatus of claim 12, wherein the operations further comprise: determining that the second connection instance is not available for the PLMN search; as well as Responsively terminating the PLMN search on the second connection instance.

17. The apparatus of claim 16, wherein the operations further comprise: Before terminating the PLMN search, a PLMN found on the searched frequency band is identified.

18. The apparatus of claim 16, wherein the operations further comprise: Resume the PLMN search on the first connection instance.

19. The apparatus of claim 12, wherein the apparatus is a user equipment (UE) or a baseband processor.

20. A method comprising: Determining to perform a public land mobile network PLMN search on the first connection instance; Determining that the connection instance is in a radio resource control (RRC) connected mode; determining whether a second connection instance is available for the PLMN search; as well as In response to determining that the second connection instance is available, the PLMN search is performed on the second connection instance, wherein the PLMN search includes one or more frequency scans.

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