Multi-subscriber identity module (SIM) selection of primary SIM for wakeup signal detection

Certain aspects of the present disclosure provide techniques for a user equipment (UE) to select a primary subscriber identity module (SIM) for wakeup signal detection and decoding. One example method for wireless communication by a UE having a first SIM and a second SIM includes selecting, from the first SIM and the second SIM, a primary SIM and a secondary SIM; decoding, by the primary SIM, downlink control information (DCI); indicating, by the primary SIM to the secondary SIM, a wakeup grant based on the DCI; and taking one or more actions, by at least one of the primary SIM or the secondary SIM, in response to the indication of the wakeup grant.

INTRODUCTION

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for selecting a primary subscriber identity module (SIM) for wakeup signal detection.

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources with those users (e.g., bandwidth, transmit power, or other resources). Multiple-access technologies can rely on any of code division, time division, frequency division orthogonal frequency division, single-carrier frequency division, or time division synchronous code division, to name a few. These and other multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level.

Although wireless communication systems have made great technological advancements over many years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers, undermining various established wireless channel measuring and reporting mechanisms, which are used to manage and optimize the use of finite wireless channel resources. Consequently, there exists a need for further improvements in wireless communications systems to overcome various challenges.

SUMMARY

One aspect provides a method of wireless communications by a user equipment (UE) having a first subscriber identity module (SIM) and a second SIM. The method generally includes: selecting, from the first SIM and the second SIM, a primary SIM and a secondary SIM; decoding, by the primary SIM, downlink control information (DCI); indicating, by the primary SIM to the secondary SIM, a wakeup grant based on the DCI; and taking one or more actions, by at least one of the primary SIM or the secondary SIM, in response to the indication of the wakeup grant.

Other aspects provide: an apparatus operable, configured, or otherwise adapted to perform the aforementioned methods as well as those described elsewhere herein; a non-transitory, computer-readable media comprising instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform the aforementioned methods as well as those described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising code for performing the aforementioned methods as well as those described elsewhere herein; and an apparatus comprising means for performing the aforementioned methods as well as those described elsewhere herein. By way of example, an apparatus may comprise a processing system, a device with a processing system, or processing systems cooperating over one or more networks.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable mediums for a multi-subscriber identity module (SIM) user equipment (UE) to select a primary SIM for wakeup signal detection.

In some wireless communications networks, a network (e.g., a network entity, such as a BS) may configure a UE to perform connected mode discontinuous reception (C-DRX), wherein a receiver(s) of the UE is activated (e.g., powered up or tuned to the network's frequency band) during C-DRX on-durations at regular intervals and deactivated (e.g., powered down or tuned to another frequency band) during C-DRX off-durations between those intervals. If the network has data to transmit to the UE, then the network delays that transmission until an on-duration when the UE's receiver will be active. Upon beginning to receive a transmission from the network, the UE keeps its receiver active until the network has stopped transmitting to the UE for a period. By using C-DRX, a UE may save power as compared to having a receiver of the UE continually active. However, some UEs that have multiple SIMs, are experiencing relatively high mobility (e.g., mobility that is high enough to cause an increase in synchronization errors, such as walking speed with mmWave communications, automobile speeds for lower frequencies, or lower speeds for lower frequency communications in dense, urban environments) or are running applications communicating (e.g., transmitting or receiving) critical data (e.g., data of ultra-reliable low-latency communications (URLLC), data for applications with low-latency quality of service (QoS) characteristics, or data for applications with high reliability QoS characteristics) may have the reliability or performance of the connection to the network negatively impacted by being configured with some C-DRX parameters.

In aspects of the present disclosure, a UE may detect a condition which may cause some C-DRX parameters to negatively impact reliability or performance of a connection to a wireless network, and in response the UE may transmit a request to change the C-DRX parameters. For example, a UE that has multiple SIMs (e.g., a multi-SIM UE) supporting multiple network subscriptions may be configured such that C-DRX on-durations on a first subscription consistently conflict with (e.g., overlap in time) paging opportunities (POs) of a second subscription. In the example, the UE can transmit a request to change an offset or length of the C-DRX on-durations so that the on-durations do not consistently conflict with the POs of the other subscription, and the UE is less likely to miss pages from the network of the other subscription. In another example, a multi-SIM UE may be configured such that C-DRX on-durations of a first subscription consistently conflict with C-DRX on-durations of a second subscription, and the UE may request to change an offset or length of one or both of the C-DRX configurations to that the on-durations of the two subscriptions conflict less often. In still another example, a UE may be experiencing high mobility, which is causing the UE to have frequent changes to a timing advance (TA) parameter of the UE. In this example, the UE can request to shorten intervals between on-durations so that the UE can receive the more frequent TA changes from the network. In yet another example, a UE may be running an application that communicates critical data, and the UE may request to shorten intervals between on-durations so that the UE can transmit or receive the critical data more often.

By requesting a change to C-DRX parameters, a UE can notify the network to change the C-DRX parameters, and, if the network makes the requested change, then reliability or performance of the connection to the wireless network can be improved. This may improve overall reliability of the wireless communications system.

Introduction to Wireless Communication Networks

FIG.1depicts an example of a wireless communication network100, in which aspects described herein may be implemented.

Generally, wireless communication network100includes base stations (BSs)102, user equipments (UEs)104, and one or more core networks, such as an Evolved Packet Core (EPC)160and 5G Core (5GC) network190, which interoperate to provide wireless communications services.

BSs102may provide an access point to the EPC160and/or 5GC190for a UE104, and may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, delivery of warning messages, among other functions. Base stations may include and/or be referred to as a gNB, NodeB, eNB, ng-eNB (e.g., an eNB that has been enhanced to provide connection to both EPC160and 5GC190), an access point, a base transceiver station, a radio base station, a radio transceiver, or a transceiver function, or a transmission reception point in various contexts.

A base station, such as BS102, may include components that are located at a single physical location or components located at various physical locations. In examples in which the base station includes components that are located at various physical locations, the various components may each perform various functions such that, collectively, the various components achieve functionality that is similar to a base station that is located at a single physical location. As such, a base station may equivalently refer to a standalone base station or a base station including components that are located at various physical locations or virtualized locations. In some implementations, a base station including components that are located at various physical locations may be referred to as or may be associated with a disaggregated radio access network (RAN) architecture, such as an Open RAN (O-RAN) or Virtualized RAN (VRAN) architecture. In some implementations, such components of a base station may include or refer to one or more of a central unit (CU), a distributed unit (DU), or a radio unit (RU).

BSs102wirelessly communicate with UEs104via communications links120. Each of BSs102may provide communication coverage for a respective geographic coverage area110, which may overlap in some cases. For example, small cell102′ (e.g., a low-power base station) may have a coverage area110′ that overlaps the coverage area110of one or more macrocells (e.g., high-power base stations).

The communication links120between BSs102and UEs104may include uplink (UL) (also referred to as reverse link) transmissions from a UE104to a BS102and/or downlink (DL) (also referred to as forward link) transmissions from a BS102to a UE104. The communication links120may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity in various aspects.

Examples of UEs104include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player, a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or other similar devices. Some of UEs104may be internet of things (IoT) devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, or other IoT devices), always on (AON) devices, or edge processing devices. UEs104may also be referred to more generally as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, or a client.

Communications using higher frequency bands may have higher path loss and a shorter range compared to lower frequency communications. Accordingly, certain base stations (e.g.,180inFIG.1) may utilize beamforming182with a UE104to improve path loss and range. For example, base station180and the UE104may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

In some cases, base station180may transmit a beamformed signal to UE104in one or more transmit directions182′. UE104may receive the beamformed signal from the base station180in one or more receive directions182″. UE104may also transmit a beamformed signal to the base station180in one or more transmit directions182″. Base station180may also receive the beamformed signal from UE104in one or more receive directions182′. Base station180and UE104may then perform beam training to determine the best receive and transmit directions for each of base station180and UE104. Notably, the transmit and receive directions for base station180may or may not be the same. Similarly, the transmit and receive directions for UE104may or may not be the same.

Wireless communication network100further includes Primary Subscription Selection Component198, which may be used configured to select a primary SIM for wakeup signal detection.

FIG.2depicts aspects of an example BS102and a UE104. Generally, BS102includes various processors (e.g.,220,230,238, and240), antennas234a-t(collectively234), transceivers232a-t(collectively232), which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source212) and wireless reception of data (e.g., data sink239). For example, BS102may send and receive data between itself and UE104.

BS102includes controller/processor240, which may be configured to implement various functions related to wireless communications.

Generally, UE104includes various processors (e.g.,258,264,266, and280), antennas252a-r(collectively252), transceivers254a-r(collectively254), which include modulators and demodulators, and other aspects, which enable wireless transmission of data (e.g., data source262) and wireless reception of data (e.g., data sink260).

UE104includes controller/processor280, which may be configured to implement various functions related to wireless communications. In the depicted example, controller/processor280includes Primary Subscription Selection Component281, which may be representative of Primary Subscription Selection Component198ofFIG.1. Notably, while depicted as an aspect of controller/processor280, Primary Subscription Selection Component281may be implemented additionally or alternatively in various other aspects of UE104in other implementations.

FIGS.3A,3B,3C, and3Ddepict aspects of data structures for a wireless communication network, such as wireless communication network100ofFIG.1. In particular,FIG.3Ais a diagram300illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure,FIG.3Bis a diagram330illustrating an example of DL channels within a 5G subframe,FIG.3Cis a diagram350illustrating an example of a second subframe within a 5G frame structure, andFIG.3Dis a diagram380illustrating an example of UL channels within a 5G subframe.

Further discussions regardingFIG.1,FIG.2, andFIGS.3A,3B,3C, and3Dare provided later in this disclosure.

Introduction to Connected Mode Discontinuous Reception

As illustrated in an example timing diagram400ofFIG.4, during periods of traffic inactivity, a user equipment (UE) may switch to a connected discontinuous reception (C-DRX) operation for power saving. A UE may be configured for C-DRX according to various configuration parameters, such as an inactivity timer, a short DRX timer, a short DRX cycle, and a long DRX cycle.

Based on configured cycles, the UE wakes up occasionally for ON durations and monitors for physical downlink control channel (PDCCH) transmissions. Except for ON durations, the UE may remain in a low power (sleep) state referred to as an OFF duration, for the rest of C-DRX cycle. During the OFF duration, the UE is not expected to transmit and receive any signal.

In a C-DRX mode, a UE wakes up and transmits and/or receives (TX/RX) data packets following C-DRX cycle (during a C-DRX ON period). In some cases, if the UE detects a PDCCH scheduling data during ON duration, the UE remains ON to transmit and receive data. Otherwise, the UE goes back to sleep at the end of the ON duration. This type of C-DRX mode has been used many years and is still default behavior of some new radio (NR) networks and UEs.

In some cases, with periodic C-DRX cycles, a UE may wake up frequently even when the UE has no data to transmit and/or to monitor for data (e.g., indicated by a page), which wastes UE power. Enlarging a C-DRX cycle may cause UEs to wake up less often, but this may also lead to increased data service latency (e.g., if a UE has packets to transmit well before the next C-DRX on duration).

Example Disaggregated Base Station Architecture

FIG.5depicts an example disaggregated base station500architecture. The disaggregated base station500architecture may include one or more central units (CUs)510that can communicate directly with a core network520via a backhaul link, or indirectly with the core network520through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC)525via an E2 link, or a Non-Real Time (Non-RT) RIC515associated with a Service Management and Orchestration (SMO) Framework505, or both). A CU510may communicate with one or more distributed units (DUs)530via respective midhaul links, such as an F1 interface. The DUs530may communicate with one or more radio units (RUs)540via respective fronthaul links. The RUs540may communicate with respective UEs104via one or more radio frequency (RF) access links. In some implementations, the UE104may be simultaneously served by multiple RUs540.

Lower-layer functionality can be implemented by one or more RUs540. In some deployments, an RU540, controlled by a DU530, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s)540can be implemented to handle over the air (OTA) communication with one or more UEs104. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s)540can be controlled by the corresponding DU530. In some scenarios, this configuration can enable the DU(s)530and the CU510to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework505may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework505may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO Framework505may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud)590) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements can include, but are not limited to, CUs510, DUs530, RUs540and Near-RT RICs525. In some implementations, the SMO Framework505can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB)511, via an O1 interface. Additionally, in some implementations, the SMO Framework505can communicate directly with one or more RUs540via an O1 interface. The SMO Framework505also may include a Non-RT RIC515configured to support functionality of the SMO Framework505.

The Non-RT RIC515may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC525. The Non-RT RIC515may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC525. The Near-RT RIC525may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs510, one or more DUs530, or both, as well as an O-eNB, with the Near-RT RIC525.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC525, the Non-RT RIC515may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC525and may be received at the SMO Framework505or the Non-RT RIC515from non-network data sources or from network functions. In some examples, the Non-RT RIC515or the Near-RT RIC525may be configured to tune RAN behavior or performance. For example, the Non-RT RIC515may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework505(such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies).

Example Multiple Subscriber Identity Module (Multi-SIM) Device

FIG.6illustrates an example multi-subscriber identity module (multi-SIM) deployment600, in which a UE604supports multiple SIMs, SIM1606and SIM2608, which may support the same or different radio access technologies (RATs). The UE604may be an example of UE104, shown inFIGS.1and2. SIM1 may have a subscription to a first network. The UE may communicate with that first network via a BS610. SIM2 may have a subscription to a second network. The UE may communicate with that second network via a BS620. Each of BS610and620may be examples of BS102, shown inFIGS.1and2. At any given time, the SIMs606and608may concurrently be in an idle state and may support different modes of operation. For example, if the UE has a single receiver, then the UE may support a Single Receive Dual SIM Dual Standby (SR-DSDS) mode, where only one RAT is received at a time. In another example, if the UE has two receivers, then the UE may support a Dual Receive Dual SIM Dual Standby (DR-DSDS) mode, wherein the UE may simultaneously receive multiple RATs.

Aspects Related to Selecting a Primary SIM For Wakeup Signal Detection

New radio (NR) wakeup signaling provides user equipments (UEs) with a means for saving power.FIG.7Aillustrates an example timeline700A for wakeup signal decoding and sharing by both SIMs in a multi-SIM UE. As shown, in a multi-SIM device, such as a dual subscriber identity module (SIM) dual active (DSDA) UE, when both SIMs are in connected mode, both SIMs may wake up during an ON duration to monitor for a wakeup signal and to decode control information (e.g., control information with a DCI_2_6 format) in PDCCH each time that a wakeup signal is sent, whether or not a grant is present. Waking up both SIMs for wakeup signal detection and decoding requires increased battery power of mobile semiconductor devices.

Accordingly, in cases where both subscriptions have same public land mobile network (PLMN), instead of waking up both SIMs (e.g., subscriptions), it may be desirable for only one of the SIMs to wake up and decode the grant on behalf of both SIMs in order to save power. The SIM that is selected to perform the wakeup signal monitoring and decoding may be referred to as the primary SIM, and the other SIM may be referred to as the secondary SIM. The primary SIM may also perform wakeup signal sharing upon detection and decoding of a wakeup signal. Wakeup signal sharing may allow the primary SIM to help make the secondary SIM aware of the wakeup signal before the secondary SIM would have detected and decoded the grant.

In aspects of the present disclosure, a multi-SIM device (e.g., a UE having a first SIM and a second SIM) may select, from the first SIM and the second SIM, a primary SIM and a secondary SIM. The primary SIM may monitor for a wakeup signal on behalf of both SIMs. The primary SIM may decode downlink control information (DCI) which includes a wakeup grant. The primary SIM may then indicate the wakeup grant to the second SIM based on the DCI. In response to the indication of the wakeup grant, at least one of the primary SIM and the secondary SIM may take one or more actions. For example, the secondary SIM may be configured to exit a sleep mode (e.g., wake up) in response to the indication of the wakeup grant. The secondary SIM may also be configured to monitor for one or more signals in response to the indication of the wakeup grant.

FIG.7Billustrates an example timeline700B for wakeup signal decoding and sharing by a primary SIM. In this case, a first SIM (e.g., Sub1) may be selected as the primary SIM. As illustrated, instead of waking up both SIMs for wakeup detection and decoding, Sub1 performs wakeup signal detection, while a second SIM (e.g., Sub2) does not (e.g., as illustrated by the “X” over Sub2). That is, in some cases, only the primary SIM decodes DCI. Sub1 may then indicate (e.g., share) the wakeup signal with Sub2 (e.g., as illustrated by the arrow from Sub1 to Sub2).

The UE may consider several factors when determining which SIM to select as the primary SIM. In one example aspect, one of the SIMs may be operating in a connected mode and the other SIM may be operating in a connected discontinuous repetition (DRX) mode. The connected mode may be a mode in which the SIM is continuously connected to the network (e.g., no DRX is performed). In this case, because the SIM in connected DRX mode is in an idle mode and only periodically wakes up, power saving may be achieved by keeping the connected DRX SIM in the idle mode. Accordingly, the SIM in connected mode may be selected as the primary SIM to decode the wakeup signal (e.g., obtain control information in a DCI_2_6 format) for the other SIM whenever a grant is received. As a result, the connected DRX SIM does not use power to wake up, thereby saving battery power.

In one example aspect, both SIMs may operate in the connected DRX mode. Additionally, one of the SIMs may have a higher DRX cycle periodicity than the other (e.g., one SIM may enter an ON duration to monitor for a wakeup signal more frequently than the other SIM). In this case, it may be desirable to select the SIM with a higher DRX cycle periodicity as the primary SIM. For example, if a first SIM performs a DRX check every 80 ms and a second SIM performs DRX check every 160 ms then the first SIM should be selected since it will check for the wakeup signal more frequently. The UE may skip waking up the secondary SIM since the primary SIM is configured to check for wakeup signals more frequently than the secondary SIM, and therefore has a higher likelihood of detecting a wakeup signal during a given DRX cycle. This allows the UE to improve power savings without impacting performance (e.g., without creating latency issues).

In another example aspect, if both SIMs have the same DRX cycle periodicity, then the SIM with better signal strength may be chosen to perform the wakeup signal detecting and decoding. The UE with better signal strength may be more reliable and have a higher likelihood of detecting a grant. In determining signal strength, the UE may measure the signal-to-noise ratio (SNR) for each of the SIMs. In some cases, the UE may prioritize the SIM with the better signal strength over the SIM with the higher periodicity. The UE may reevaluate the signal strength when it moves to another area, for example, when entering a new cell.

In some examples, the UE may consider historical transmission data when selecting a primary SIM. For example, the UE may select the SIM that has had more transmissions and receptions in a recent time period as the primary SIM.

In some cases, the UE may determine to not select a primary SIM when both SIMs have very low DRX cycle periodicity (e.g., greater than 160 ms) to avoid latency issue. For example, if both SIMs perform DRX check every 320 ms, then the UE may have both SIMs wake up for decoding WUS. The threshold for DRX cycle periodicity may be selected based on whether the secondary SIM would receive the wakeup signal from the primary SIM and wake up in time to receive and act on the corresponding grant.

Example Wireless Methods

FIG.8illustrates example operations800for wireless communications by a UE, in accordance with certain aspects of the present disclosure. For example, operations800may be performed by a user equipment (UE)104ofFIG.1for selecting a primary subscriber identity module (SIM) for wakeup signal detection.

Operations800begin at810, with the UE selecting, from a first SIM and a second SIM, a primary SIM and a secondary SIM. At820, the primary SIM may decode downlink control information (DCI). In some cases, only the primary SIM (and not the secondary SIM) decodes the DCI.

At830, the primary SIM may indicate to the secondary SIM a wakeup grant based on the DCI. In some examples, the secondary SIM may be configured to remain in a sleep mode until the primary SIM indicates the wakeup grant. At840, at least one of the primary SIM or the secondary SIM may take one or more actions in response to the indication of the wakeup grant.

In some examples, selecting the primary SIM involves determining that one of the first SIM and the second SIM is in a connected mode; determining that another one of the first SIM or the second SIM is in a connected discontinuous reception (DRX) mode; and selecting, as the primary SIM, the SIM that is in the connected mode.

In certain other examples, the first SIM and the second SIM may both be in a connected discontinuous reception (DRX) mode. In this case, selecting the primary SIM may involve determining that the first SIM is configured to perform DRX at a first periodicity; determining that the second SIM is configured to perform DRX at a second periodicity; and selecting the primary SIM based on the first and second periodicities. In some cases, selecting the primary SIM based on the first and second periodicities involves selecting the first SIM when the first periodicity is higher than the second periodicity; and selecting the second SIM when the second periodicity is higher than the first periodicity. In some examples, the first and second periodicities are less than or equal to 1/160 ms.

In some examples, where the first SIM and the second SIM may both be in a connected DRX mode, selecting the primary SIM may involve estimating a first signal strength of the first SIM and a second signal strength of the second SIM; and selecting the primary SIM based on the first and second signal strengths. In this case, selecting the primary SIM based on the first and second signal strengths may involve selecting the first SIM when the first signal strength is greater than the second signal strength; and selecting the second SIM when the second signal strength is greater than the first signal strength.

In some examples, when the UE enters a new cell, the operations800may further involve estimating a first signal strength of the first SIM and a second signal strength of the second SIM when the UE enters a new cell. In certain examples, the first and second signal strengths may be estimated based on a signal-to-noise ratio (SNR), and wherein a higher SNR value indicates a greater signal strength.

According to certain aspects, selecting the primary SIM may involve storing data related to transmission and reception history of the first SIM and the second SIM; and selecting the primary SIM based on the stored data. In some examples, selecting the primary SIM based on the stored data may involve selecting, based on the stored data related to transmission and reception history, the SIM that receives more data. In some examples, selecting the primary SIM based on the stored data may involve selecting, based on the stored data related to transmission and reception history, the SIM that transmits more data.

Example Wireless Communication Device

FIG.9depicts an example communications device900that includes various components operable, configured, or adapted to perform operations for the techniques disclosed herein. In some examples, communication device900may be a UE104as described, for example with respect toFIGS.1and2.

Communications device900includes a processing system902coupled to a transceiver908(e.g., a transmitter and/or a receiver). Transceiver908is configured to transmit (or send) and receive signals for the communications device900via an antenna910, such as the various signals as described herein. Processing system902may be configured to perform processing functions for communications device900, including processing signals received and/or to be transmitted by communications device900.

Processing system902includes one or more processors920coupled to a computer-readable medium/memory930via a bus906. In certain aspects, computer-readable medium/memory930is configured to store instructions (e.g., computer-executable code) that when executed by the one or more processors920, cause the one or more processors920to perform the various techniques discussed herein for selecting a primary SIM for wakeup signal detection and decoding to improve power saving.

In the depicted example, computer-readable medium/memory930stores code931for selecting, from a first SIM and a second SIM, a primary SIM and a secondary SIM, code932for decoding, by the primary SIM, downlink control information (DCI), code933for indicating, by the primary SIM to the secondary SIM, a wakeup grant based on the DCI, and code934for taking one or more actions, by at least one of the primary SIM or the secondary SIM, in response to the indication of the wakeup grant.

In the depicted example, the one or more processors920include circuitry configured to implement the code stored in the computer-readable medium/memory930, including circuitry921for selecting, from the first SIM and the second SIM, a primary SIM and a secondary SIM, circuitry922for decoding, by the primary SIM, DCI, circuitry923for indicating, by the primary SIM to the secondary SIM, a wakeup grant based on the DCI, and circuitry924for taking one or more actions, by at least one of the primary SIM or the secondary SIM, in response to the indication of the wakeup grant.

Various components of communications device900may provide means for performing the methods described herein.

In some examples, means for transmitting or sending (or means for outputting for transmission) may include the transceivers254and/or antenna(s)252of the UE104illustrated inFIG.2and/or transceiver908and antenna910of the communication device900inFIG.9.

In some examples, means for receiving (or means for obtaining) may include the transceivers254and/or antenna(s)252of the UE104illustrated inFIG.2and/or transceiver908and antenna910of the communication device900inFIG.9.

In some examples, means for detecting or determining may include various processing system components, such as: the one or more processors920inFIG.9, or aspects of the UE104depicted inFIG.2, including receive processor258, transmit processor264, TX MIMO processor266, and/or controller/processor280(including Primary Subscription Selection Component281).

Notably,FIG.9is an example, and many other examples and configurations of communication device900are possible.

Example Clauses

Clause 1: A method for wireless communication by a user equipment (UE) having a first subscriber identity module (SIM) and a second SIM, comprising: selecting, from the first SIM and the second SIM, a primary SIM and a secondary SIM; decoding, by the primary SIM, downlink control information (DCI); indicating, by the primary SIM to the secondary SIM, a wakeup grant based on the DCI; and taking one or more actions, by at least one of the primary SIM or the secondary SIM, in response to the indication of the wakeup grant.

Clause 2: The method of clause 1, wherein only the primary SIM decodes the DCI.

Clause 3: The method of clause 2, wherein the secondary SIM is configured to remain in a sleep mode until the primary SIM indicates the wakeup grant.

Clause 4: The method of any one of clauses 1-3, wherein taking one or more actions comprises at least one of: exiting, by the second SIM, a sleep mode; or monitoring, by the second SIM, for one or more signals.

Clause 5: The method of any one of clauses 1-4, wherein selecting the primary SIM comprises: determining that one of the first SIM and the second SIM is in a connected mode; and determining that another one of the first SIM or the second SIM is in a connected discontinuous reception (DRX) mode; and selecting, as the primary SIM, the SIM that is in the connected mode.

Clause 6: The method of any one of clauses 1-5, wherein the first SIM and the second SIM are in a connected discontinuous reception (DRX) mode, and selecting the primary SIM comprises: determining that the first SIM is configured to perform DRX at a first periodicity; determining that the second SIM is configured to perform DRX at a second periodicity; and selecting the primary SIM based on the first and second periodicities.

Clause 7: The method of clause 6, wherein selecting the primary SIM based on the first and second periodicities comprises: selecting the first SIM when the first periodicity is higher than the second periodicity; and selecting the second SIM when the second periodicity is higher than the first periodicity.

Clause 8: The method of any one of clauses 6 and 7, wherein the first and second periodicities are less than or equal to 1/160 ms.

Clause 9: The method of any one of clauses 1-8, wherein the first SIM and the second SIM are in a connected discontinuous reception (DRX) mode, and selecting the primary SIM comprises: estimating a first signal strength of the first SIM and a second signal strength of the second SIM; and selecting the primary SIM based on the first and second signal strengths.

Clause 10: The method of clause 9, wherein selecting the primary SIM based on the first and second signal strengths comprises: selecting the first SIM when the first signal strength is greater than the second signal strength; and selecting the second SIM when the second signal strength is greater than the first signal strength.

Clause 11: The method of clause 10, further comprising, when the UE enters a new cell, estimating a first signal strength of the first SIM and a second signal strength of the second SIM when the UE enters a new cell.

Clause 12: The method of any one of clauses 10 and 11, wherein the first and second signal strengths are estimated based on a signal-to-noise ratio (SNR), and wherein a higher SNR value indicates a greater signal strength.

Clause 13: The method of any one of clauses 1-12, wherein selecting the primary SIM comprises: storing data related to transmission and reception history of the first SIM and the second SIM; and selecting the primary SIM based on the stored data.

Clause 14: The method of clause 13, wherein selecting the primary SIM based on the stored data comprises selecting, based on the stored data related to transmission and reception history, the SIM that receives more data.

Clause 15: The method of any one of clauses 13 and 14, wherein selecting the primary SIM based on the stored data comprises selecting, based on the stored data related to transmission and reception history, the SIM that transmits more data.

Additional Wireless Communication Network Considerations

The techniques and methods described herein may be used for various wireless communications networks (or wireless wide area network (WWAN)) and radio access technologies (RATs). While aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G (e.g., 5G new radio (NR)) wireless technologies, aspects of the present disclosure may likewise be applicable to other communication systems and standards not explicitly mentioned herein.

5G wireless communication networks may support various advanced wireless communication services, such as enhanced mobile broadband (eMBB), millimeter wave (mmWave), machine type communications (MTC), and/or mission critical targeting ultra-reliable, low-latency communications (URLLC). These services, and others, may include latency and reliability requirements.

Returning toFIG.1, various aspects of the present disclosure may be performed within the example wireless communication network100.

In 3GPP, the term “cell” can refer to a coverage area of a NodeB and/or a narrowband subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and BS, next generation NodeB (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmission reception point may be used interchangeably. A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells.

A macro cell may generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area (e.g., a sports stadium) and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) and UEs for users in the home). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS, home BS, or a home NodeB.

Some base stations, such as gNB180may operate in a traditional sub-6 GHz spectrum, in millimeter wave (mmWave) frequencies, and/or near mmWave frequencies in communication with the UE104. When the gNB180operates in mmWave or near mmWave frequencies, the gNB180may be referred to as an mmWave base station.

The communication links120between base stations102and, for example, UEs104, may be through one or more carriers. For example, base stations102and UEs104may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, and other MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell).

Wireless communications system100further includes a Wi-Fi access point (AP)150in communication with Wi-Fi stations (STAs)152via communication links154in, for example, a 2.4 GHz and/or 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs152/AP150may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

EPC160may include a Mobility Management Entity (MME)162, other MMEs164, a Serving Gateway166, a Multimedia Broadcast Multicast Service (MBMS) Gateway168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway172. MME162may be in communication with a Home Subscriber Server (HSS)174. MME162is the control node that processes the signaling between the UEs104and the EPC160. Generally, MME162provides bearer and connection management.

5GC190may include an Access and Mobility Management Function (AMF)192, other AMFs193, a Session Management Function (SMF)194, and a User Plane Function (UPF)195. AMF192may be in communication with a Unified Data Management (UDM)196.

AMF192is generally the control node that processes the signaling between UEs104and 5GC190. Generally, AMF192provides QoS flow and session management.

All user Internet protocol (IP) packets are transferred through UPF195, which is connected to the IP Services197, and which provides UE IP address allocation as well as other functions for 5GC190. IP Services197may include, for example, the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services.

Returning toFIG.2, various example components of BS102and UE104(e.g., the wireless communication network100ofFIG.1) are depicted, which may be used to implement aspects of the present disclosure.

At BS102, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), and others. The data may be for the physical downlink shared channel (PDSCH), in some examples.

A medium access control (MAC)-control element (MAC-CE) is a MAC layer communication structure that may be used for control command exchange between wireless nodes. The MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel (PSSCH).

Processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor220may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), PBCH demodulation reference signal (DMRS), and channel state information reference signal (CSI-RS).

At UE104, antennas252a-252rmay receive the downlink signals from the BS102and may provide received signals to the demodulators (DEMODs) in transceivers254a-254r, respectively. Each demodulator in transceivers254a-254rmay condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM) to obtain received symbols.

MIMO detector256may obtain received symbols from all the demodulators in transceivers254a-254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor258may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE104to a data sink260, and provide decoded control information to a controller/processor280.

On the uplink, at UE104, transmit processor264may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source262and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor280. Transmit processor264may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)). The symbols from the transmit processor264may be precoded by a TX MIMO processor266if applicable, further processed by the modulators in transceivers254a-254r(e.g., for SC-FDM), and transmitted to BS102.

At BS102, the uplink signals from UE104may be received by antennas234a-t, processed by the demodulators in transceivers232a-232t, detected by a MIMO detector236if applicable, and further processed by a receive processor238to obtain decoded data and control information sent by UE104. Receive processor238may provide the decoded data to a data sink239and the decoded control information to the controller/processor240.

Memories242and282may store data and program codes for BS102and UE104, respectively.

Scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

As above,FIGS.3A-3Ddepict various example aspects of data structures for a wireless communication network, such as wireless communication network100ofFIG.1.

In various aspects, the 5G frame structure may be frequency division duplex (FDD), in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for either DL or UL. 5G frame structures may also be time division duplex (TDD), in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided byFIGS.3A and3C, the 5G frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL), where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL). While subframes 3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI), or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the description below applies also to a 5G frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. In some examples, each slot may include 7 or 14 symbols, depending on the slot configuration.

For example, for slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission).

As illustrated inFIG.3A, some of the REs carry reference (pilot) signals (RS) for a UE (e.g., UE104ofFIGS.1and2). The RS may include demodulation RS (DM-RS) (indicated as Rx for one particular configuration, where 100× is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

FIG.3Billustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol.

A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE (e.g.,104ofFIGS.1and2) to determine subframe/symbol timing and a physical layer identity.

Additional Considerations