PATENT DOCUMENT

Publication Number: US-10827376-B2
Application Number: US-201916546334-A
Country: US
Kind Code: B2

Title: Processing requests for measurement of signal quality at the location of a user equipment with multiple subscriptions

Abstract:
Methods and apparatus for processing requests for signal quality measurement are provided herein. According to at least one aspect, a communication device, which has a plurality of subscriptions, maintains first state parameter information for one or more subscriptions of the plurality of subscriptions to indicate whether a call is ongoing for each subscription of the one or more subscriptions. The communication device receives, for a further subscription of the plurality of subscriptions, a request to measure a channel condition of one or more signals. The communication device responds to the request to measure the channel condition of the one or more signals based on a determination that the first state parameter information for the one or more subscriptions indicates no call is ongoing for each subscription of the one or more subscriptions.

Claims:
We claim: 
     
       1. A communication device comprising:
 a plurality of subscriptions including:
 a first subscription to a first wireless network, and 
 a second subscription a second wireless network; 
 
 a transceiver including a transmission chain common to both the first subscription and the second subscription; and 
 one or more processors configured to:
 maintain first state parameter information for the first subscription to indicate whether a call is ongoing for the first subscription, 
 receive, for the second subscription, a request to measure a channel condition of one or more signals, and 
 respond to the request to measure the channel condition of the one or more signals based on a determination that the first state parameter information for the first subscription indicates no call is ongoing for the first subscription. 
 
 
     
     
       2. The communication device of  claim 1 ,
 wherein the first subscription is associated with a first subscriber identity module (SIM), and 
 wherein the second subscription is associated with a second SIM. 
 
     
     
       3. The communication device of  claim 1 ,
 wherein the first wireless network is different from the second wireless network. 
 
     
     
       4. The communication device of  claim 1 ,
 wherein the first wireless network is the same as the second wireless network. 
 
     
     
       5. The communication device of  claim 1 ,
 wherein the channel condition is a received signal strength indicator (RSSI). 
 
     
     
       6. The communication device of  claim 1 ,
 wherein the plurality of subscriptions further includes a third subscription to a third wireless network; and 
 wherein the one or more processors are further configured to:
 maintain first state parameter information for the third subscription to indicate whether a call is ongoing for the third subscription, and 
 respond to the request to measure the channel condition of the one or more signals further based on a determination that the first state parameter information for the third subscription indicates no call is ongoing for the third subscription. 
 
 
     
     
       7. The communication device of  claim 1 ,
 wherein the call is a voice over long term evolution (VoLTE) call. 
 
     
     
       8. The communication device of  claim 1 ,
 wherein the request to measure the channel condition of the one or more signals is included in a radio resource control (RRC) connection reconfiguration message. 
 
     
     
       9. The communication device of  claim 1 ,
 wherein the one or more processors are further configured to:
 maintain second state parameter information for the first subscription to indicate whether an RRC connection is established for the first subscription, and 
 respond to the request to measure the channel condition of the one or more signals further based on a determination that the second state parameter information for the first subscription indicates no RRC connection is established for the first subscription. 
 
 
     
     
       10. The communication device of  claim 1 ,
 wherein the one or more processors are further configured to:
 maintain third state parameter information for the first subscription to indicate whether a default radio bearer connection is established for the first subscription, and 
 respond to the request to measure the channel condition of the one or more signals further based on a determination that the third state parameter information for the first subscription indicates no default radio bearer connection is established for the first subscription. 
 
 
     
     
       11. A method of a communication device having a plurality of subscriptions, the method comprising:
 maintaining first state parameter information for one or more subscriptions of the plurality of subscriptions to indicate whether a call is ongoing for each subscription of the one or more subscriptions; 
 receiving, for a further subscription of the plurality of subscriptions, a request to measure a channel condition of one or more signals; and 
 responding to the request to measure the channel condition of the one or more signals based on a determination that the first state parameter information for the one or more subscriptions indicates no call is ongoing for each subscription of the one or more subscriptions. 
 
     
     
       12. The method of  claim 11 ,
 wherein at least one subscription of the one or more subscriptions is associated with an operation of the communication device according to a first radio access technology (RAT), and 
 wherein the further subscription is associated with an operation of the communication device according to a second RAT. 
 
     
     
       13. The method of  claim 12 ,
 wherein the first RAT and the second RAT are the same. 
 
     
     
       14. The method of  claim 12 ,
 wherein the first RAT and the second RAT are different. 
 
     
     
       15. The method of  claim 11 ,
 wherein receiving, for the further subscription, the request to measure the channel condition of the one or more signals comprises:
 receiving, for the further subscription, a request to measure a signal quality of a carrier signal of neighboring network access node within communication range of the communication device. 
 
 
     
     
       16. The method of  claim 11 ,
 wherein receiving, for the further subscription, the request to measure the channel condition of the one or more signals comprises:
 receiving, for the further subscription, a request to measure a signal quality of a carrier signal of an access point (AP) of a wireless local area network (WLAN) within communication range of the communication device. 
 
 
     
     
       17. The method of  claim 11 , further comprising:
 measuring the channel condition of the one or more signals based on the determination that the first state parameter information for the one or more subscriptions indicates no call is ongoing for each subscription of the one or more subscriptions; and 
 encoding at least one measured value of the channel condition of the one or more signals into a packet for transmission. 
 
     
     
       18. The method of  claim 17 ,
 wherein responding to the request to measure the channel condition of the one or more signals comprises:
 transmitting the packet to an evolved node B (eNodeB) using a transmission chain of the communication device; and 
 
 wherein the transmission chain is common to the plurality of subscriptions. 
 
     
     
       19. The method of  claim 11 , further comprising:
 maintaining second state parameter information for the one or more subscriptions to indicate whether an RRC connection is established for each subscription of the one or more subscriptions, 
 wherein responding to the request to measure the channel condition of the one or more signals comprises:
 responding to the request to measure the channel condition of the one or more signals further based on a determination that the second state parameter information for the one or more subscriptions indicates no RRC connection is established for each subscription of the one or more subscriptions. 
 
 
     
     
       20. One or more non-transitory computer-readable media storing instructions thereon, which when executed by at least one processor of a communication device, direct the communication device to:
 maintain first state parameter information for a plurality of subscriptions of the communication device to indicate whether a voice call is ongoing for each subscription of the plurality of subscriptions; 
 receive, for a subscription of the plurality of subscriptions, a request to measure a channel condition of one or more signals; and 
 respond to the request to measure the channel condition of the one or more signals based on a determination that the first state parameter information for the plurality of subscriptions indicates that no voice call is ongoing for each subscription of the plurality of subscriptions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/688,910, filed Aug. 29, 2017, which claims priority to Indian Patent Application Serial No. 201641033551, filed Sep. 30, 2016. The disclosures of each of the foregoing documents are incorporated herein by reference in their entirety and for all purposes. 
    
    
     BACKGROUND 
     Technical Field 
     Aspects of the present disclosure relate generally to user equipment used in wireless telephone networks, and more specifically to processing requests for measurement of signal quality at the location of a user equipment with multiple SIMs. 
     Related Art 
     Wireless user equipment (UE), or a wireless device in general, refers to instruments such as mobile phones using which users connect with mobile telephone networks on a wireless medium, as is well known in the relevant arts. In a common scenario, a UE interfaces with an eNodeB of a mobile telephone network providing the corresponding user the facility of voice and data based services. 
     UEs are provided with subscriber identity modules (SIMs). A SIM typically stores various information such as telephone number of the UE, the international mobile subscriber identity (IMSI) number (also the phone number) used by a service provider to identify and authenticate a subscriber, security keys, temporary information related to the local network, a list of the services provided by the service provider, etc. 
     A UE (or specific SIM thereon) may receive requests for measurement of signal quality at the location at which the UE is present. In response, the UE may measure the signal quality (e.g., strength of signals received from corresponding eNodeB) on various frequency bands of the cell on which the UE SIM is currently camped. Similar information may be provided with respect to other cells also covering the location of the UE. Such information may be used by the telephone network for purposes such as carrier aggregation (i.e., for sending data simultaneously on multiple channels for enhanced throughput) and hand-over the present call to a more suitable cell/eNodeB. 
     A single UE may be provided with multiple SIMs, for example, to facilitate the UE to communicate with two different telephone networks (service providers) or even the same telephone network as two different users (e.g., one as an office user and another as a personal user). Aspects of the present disclosure are directed to processing of the above noted measurement requests in such multi-SIM UEs. 
    
    
     
       BRIEF DESCRIPTION OF THE VIEWS OF DRAWINGS 
       Example aspects of the present disclosure will be described with reference to the accompanying drawings briefly described below. 
         FIG. 1  is a block diagram of an example environment in which several aspects of the present disclosure can be implemented. 
         FIG. 2  is a flow-chart illustrating the manner in which measurement requests are processed according to an aspect of the present disclosure. 
         FIG. 3  is a block diagram illustrating the details of a user equipment (UE) according to an aspect of the present disclosure. 
         FIG. 4  is a block diagram depicting a protocol stack implemented by a UE according to an aspect of the present disclosure. 
         FIGS. 5A-5D  depict entries in a table at respective time instances, representing the data structures maintained and examined by a UE in processing the measurement requests, according to an aspect of the present disclosure. 
         FIG. 6  is a timing diagram depicting the processing of a call setup request, including a measurement request, received on a second SIM when a VoLTE call is ongoing on a first SIM, according to an aspect of the present disclosure. 
     
    
    
     In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. 
     DETAILED DESCRIPTION 
     1. Overview 
     A multi-SIM wireless user equipment (UE) receives, on a second SIM, a first request to measure signal quality at a location of the UE. The UE checks whether a call is ongoing on a first SIM. The UE sends a response to the first request only if there is no call ongoing on the first SIM. 
     Several aspects of the disclosure are described below with reference to examples for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the disclosure. One skilled in the relevant arts, however, will readily recognize that the several features of the present disclosure can be practiced without one or more of the specific details, or with other methods, etc. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the features of the disclosures. 
     2. Example Environment 
       FIG. 1  is a block diagram representing an example environment in which several aspects of the present disclosure can be implemented. The example environment is shown containing only representative devices and systems for illustration. However, real world environments may contain more or fewer systems/devices.  FIG. 1  is shown containing Evolved NodeBs (eNodeB or eNB)  130  and  140 , and user equipment (UE)  120 . eNodeB  130  is assumed to have a coverage area represented by cell  100 . eNodeB  140  is also associated with a corresponding coverage area, but not shown in  FIG. 1 . eNodeB  130 , eNodeB  140  and UE  120  may operate according to any of well known standards/specifications for wireless mobile communications such as, for example, GSM (Global System for Mobile Communications), LTE (Long Term Evolution), UMTS (Universal Mobile Telecommunications System), CDMA (Code Division Multiple Access), W-CDMA (Wideband CMA), 5G, etc. Further, cell  100  and the devices therein may operate according to frequency division duplex (FDD) and/or time division duplex (TDD) modes specified by LTE also. 
     Each of eNodeB  130  and eNodeB  140  is a fixed communications unit and provides the last-mile (or last hop) communications link to UEs in the cell. Although not shown in  FIG. 1 , each of eNodeB  130  and eNodeB  140  may be connected to other devices/systems in the cellular network infrastructure to enable UEs within corresponding coverage ranges to communicate with devices (e.g., other UEs) in other cells, with landline communications equipment in a conventional PSTN, public data networks such as the internet etc., as is well known in the relevant arts. When used in other contexts such 2G and 3G technologies eNodeBs  130  and  140  may be referred to generally as base stations. The term ‘base station’ as used herein covers base stations as well as eNodeBs. Further, although noted as covering corresponding normal cell areas, each of eNodeB  130  and eNodeB  140  can also be designed to cover a much smaller area such as, for example, a macrocell, microcell or a femtocell. Macro/micro/femtocells are special cellular base stations (operating over smaller cell areas than normal cells) that are often deployed in small areas to add extra cell capacity. For example, such small cells can be deployed temporarily during sporting events and other occasions where a large number of cell phone users are expected to be concentrated in one spot. 
     UE  120  represents a wireless device such as a mobile phone, and may be used for wireless communication such as voice calls, data exchange such as web browsing, receiving and sending emails, etc. UE  120  may be equipped with multiple SIMs, each for subscription to a same or corresponding mobile network operator (e.g., AT&amp;T Mobility, Sprint, Verizon, etc.). Thus, for example, UE  120  may be equipped with one SIM for accessing services (voice and data) provided by a first mobile network operator via eNodeB  130 , and another SIM for accessing services provided by a second mobile network operator via eNodeB  140 . It is noted however that, both the first and second SIMs may designed for accessing services by a same mobile network operator also (via a same eNodeB). 
     UE  120  may receive requests for measurement of signal quality at the location at which UE  120  is present. As noted above, such measurements may be designed to enable the corresponding mobile network operator to provide higher throughput through carrier aggregation, for purposes of handover of UE  120  from a currently serviced cell to another cell, etc. Thus, for example, UE  120  may receive a measurement request from eNodeB  140  to enable eNodeB  140  to make decisions such as those noted above. The manner in which UE  120  processes such measurement requests is described next with respect to a flowchart. 
     3. Processing Measurement Requests 
       FIG. 2  is a flowchart illustrating the manner in which measurement requests are processed in a UE according to an aspect of the present disclosure. The flowchart is described with respect to the environment of  FIG. 1 , and in relation to UE  120 , merely for illustration. However, various features described herein can be implemented in other environments and using other components as well, as will be apparent to one skilled in the relevant arts by reading the disclosure provided herein. The flowchart starts in step  201 , in which control passes immediately to step  210 . 
     In step  210 , UE  120  receives, on a second SIM, a request to measure signal quality at a location of UE  120 . The signal whose quality is to be measured can be the carrier signal in corresponding frequency bands allocated for use by the mobile telephone network in the same cell as UE  120  is located currently, and/or carrier signals in neighboring cells. Generally, a higher carrier signal strength implies that the signal quality is good and can be used for reliable communication between UE  120  (using the second SIM) and the corresponding base station that serves the cell. The request can be received as part of an RRC Connection Reconfiguration message on the second SIM. Control then passes to step  220 . 
     In step  220 , UE  120  checks whether a call is ongoing on a first SIM. A call would be said to be ongoing if there are signals bearing information are being received and/or transmitted on a corresponding connection (to/from base station) for the subscriber configured on the first SIM. For illustration, it is assumed that the call is a voice call, for which uninterrupted transmission support is generally desirable for a superior user experience. However, features of the present disclosure can be applied to other types of calls for which such disruption is desirable to be avoided. Control then passes to step  230 . 
     In step  230 , UE  120  sends a response to the request (of step  210 ) only if there is no call ongoing on the first SIM. The response is formed by measuring the signal quality (as requested in the request of step  210 ) and encoding the measured values in a packet forming the response. The packet is transmitted in a known way. Control then passes to step  299 , in which the flowchart ends. 
     Although not shown in  FIG. 1 , or indicated in the flowchart above, the measurement request of step  210  may also be a request to measure carrier signal quality of one or Access Points (AP) of nearby WLANs (Wireless Local Area Networks) whose AP/Controller are within communication range of UE  120 . Such measurements may be requested with the aim of enabling carrier aggregation using APs (which are within communication range of UE  120 ), solely using such APS, or in addition to other cells. 
     Thus, when equipped with two SIMs (or in general multiple SIMs), UE  120  is designed to perform measurements and report the results to the requesting base station (i.e., the eNodeB associated with the second SIM) only if no call is ongoing on another SIM. Illustration of the above steps in example situations is provided below. However, the implementation details of UE  120  are first described. 
     4. User Equipment 
       FIG. 3  is a block diagram depicting the implementation details of a UE according to an aspect of the present disclosure. UE  120  is shown containing processing block  310 , non-volatile memory  320 , input/output (I/O) block  330 , random access memory (RAM)  340 , real-time clock (RTC)  350 , SIM1  360 A, SIM2  360 B, transmit (TX) block  370 , receive (RX) blocks  380 A and  38 B, switch  390 , and antennas  395  and  396 . Some or all units of UE  120  may be powered by a battery (not shown). UE  120  may alternatively be mains-powered and contains corresponding components such as regulators, filters, etc. The specific blocks of UE  120  are shown by way of illustration only, and UE  120  may contain more or fewer blocks depending on specific requirements. 
     According to an aspect of the present disclosure, UE  120  corresponds to a mobile phone supporting dual-SIM. The respective SIMs may subscribe to data and voice services according to one of several radio access technologies such as GSM (Global System for Mobile Communication), LTE (Long Term Evolution) (Frequency Division Duplex (FDD) as well as Time Division Duplex (TDD)), CDMA (Code Division multiple Access), WCDMA (Wideband CDMA), 3G (3 rd  generation), 5G (5 th  generation), etc, as also noted above. Further, the two SIMs can be directed to operation with the same type of radio access technology (e.g., LTE on both SIMs), or respectively different radio access technologies (e.g., LTE on one SIM and 3G on the other SIM, LTE on one SIM and CDMA on the other SIM, etc.). 
     Each of SIM1  360 A and SIM2  360 B represents a subscriber identity module (SIM) that may be provided by a mobile network operator (also known as a service provider). As is well known in the relevant arts, a SIM may store the international mobile subscriber identity (IMSI) number (which is also the phone number) used by a mobile network operator to identify and authenticate a subscriber. Additionally, a SIM may store address book/telephone numbers of subscribers, security keys, temporary information related to the local network, a list of the services provided by the service provider, etc. Though not shown, the UE is equipped with two holders, each for housing a respective one of the two SIMs  360 A and  360 B. Typically, the SIM is ‘inserted’ into such housing before the UE can access the services provided by the network operator for subscriber configured on the SIM. 
     Processing block  310  may operate to read the IMSI number, security keys etc., in transmitting and receiving voice/data respectively via TX block  370  and the corresponding one of RX block  380 A and  380 B. It is assumed herein that, SIM1 uses RX block  380 A for receiving voice/data and other signals, SIM2 uses RX block  380 B for receiving voice/data and other signals, and TX block  370  is shared by SIM1 and SIM2 for transmission of corresponding signals. 
     RTC  350  operates as a clock, and provides the ‘current’ time to processing block  310 . Additionally, RTC  350  may internally contain one or more timers. I/O block  330  provides interfaces for user interaction with UE  120 , and includes input devices and output devices. The input devices may include a keypad and a pointing device (e.g., touch-pad). Output devices may include a display with touch-sensitive screen. 
     Antenna  396  operates to receive from a wireless medium, corresponding wireless signals (representing voice, data, etc.) according to one or more standards such as LTE, and provides the received wireless signals to RX block  380 A. Antenna  396  may also be connected via a switch to a transmit block (such as TX block  370  described below), but such blocks and connections are not shown in  FIG. 3  in the interest of conciseness. 
     Antenna  395  operates to receive from, and transmit to, a wireless medium, corresponding wireless signals (representing voice, data, etc.) according to one or more standards such as LTE. Switch  390  may be controlled by processing block  310  (connection not shown) to connect antenna  395  to one of blocks  370  and  380 B as desired, depending on whether transmission or reception of wireless signals is required. Switch  390 , antenna  395  and the corresponding connections of  FIG. 3  are shown merely by way of illustration. Instead of a single antenna  395 , separate antennas, one for transmission and another for reception of wireless signals, can also be used. Further, although separate antennas  395  and  396  are shown in  FIG. 3 , a single antenna can instead be used using appropriate techniques, as would be apparent to one skilled in the relevant arts. 
     Each of RX blocks  380 A and  380 B represents a receiver (or receive chain) that receives a corresponding wireless (RF) signal bearing voice/data and/or control information via the corresponding antennas and switches, demodulates the RF signal, and provides the extracted voice/data or control information to processing block  310 . RX blocks  380 A and  380 B each may contain RF circuitry (front-end filter, low-noise amplifier, mixer/down-converter, filters) as well as baseband processing circuitry for demodulating the down-converted signal. Alternatively, RX blocks  380 A and  380 B may contain only the RF circuitry, with processing block  310  performing the baseband operations in conjunction with the RF circuitry. Data/voice for SIM1 and SIM2 are received via RX blocks  380 A and  380 B respectively. 
     TX block  370  (which represents a shared transmit chain) receives, from processing block  310 , digital signals representing information (voice, data, acknowledgements to received data, etc.) to be transmitted on a wireless medium (e.g., according to the corresponding standards/specifications), generates a modulated radio frequency (RF) signal (according to the standard), and transmits the RF signal via switch  390  and antenna  395 . TX block  370  may contain RF circuitry (mixers/up-converters, local oscillators, filters, power amplifier, etc.) as well as baseband circuitry for modulating a carrier with the baseband information signal. 
     Alternatively, TX block  370  may contain only the RF circuitry, with processing block  310  performing the modulation and other baseband operations (in conjunction with the RF circuitry). TX block  370  (or the transmit chain in general) may additionally include shared memory resources and software modules used in the transmit operations. In particular, and as described in detail below, TX block  370  is shared between SIM1 and SIM2, and therefore multiplexed by UE  120  for transmitting signals associated with operations by SIM1 and SIM2. 
     Sharing of TX block  370  (the shared transmit chain) may be achieved by processing block  310  tuning (via control signal in path  317 ) TX block  370  to the corresponding frequency band (or channel) that is desired for transmitting the respective signal (control signal or data signal). Typically, such tuning involves changing the frequency of the local oscillators and filter pass bands in the transmit chain such that the transmitted signal (at antenna  395 ) lies in the desired frequency band. 
     Thus, in the context of LTE FDD for example, for transmitting control/voice/data signals corresponding to SIM1, processing block  310  tunes the transmit chain to cause the transmitted wireless signal to lie in one (desired) frequency band, and for transmitting control/voice/data signals corresponding to SIM2, processing block  310  tunes the transmit chain to cause the transmitted wireless signal to lie in another (desired) frequency band. In the context of LTE TDD, such tuning as noted above may not be required, and processing block  310  may merely assign the transmit chain (without tuning) to the corresponding transmit operations for the respective SIM. 
     Non-volatile memory  320  is a non-transitory machine readable medium, and stores instructions, which when executed by processing block  310 , causes UE  120  to operate as described herein. In particular, the instructions enable UE  120  to operate as described with respect to the flowchart of  FIG. 2 . The instructions may either be executed directly from non-volatile memory  320  or be copied to RAM  340  for execution. 
     RAM  340  is a volatile random access memory, and may be used for storing instructions and data. RAM  340  and non-volatile memory  320  (which may be implemented in the form of read-only memory/ROM/Flash, etc.) constitute computer program products or machine (or computer) readable medium, which are means for providing instructions to processing block  310 . Processing block  310  may retrieve the instructions, and execute the instructions to provide several features of the present disclosure. 
     Processing block  310  (or processor in general) may contain multiple processing units internally, with each processing unit potentially being designed for tasks associated with a corresponding SIM. Thus, for example, processing block  310  may be implemented as separate processing cores, one each for each SIM (SIM1 and SIM2). Alternatively, processing block  310  may represent a single processing unit executing multiple execution threads in software, each execution thread handling operations for a respective SIM. In general, processing block  310  executes instructions stored in non-volatile memory  320  or RAM  340  to enable UE  120  to operate according to several aspects of the present disclosure, described in detail herein. 
       FIG. 4  illustrates an alternative view of the implementation of UE  120 , and shows example protocol stacks  400 A and  400 B implemented in UE  120  for handling operations for respective SIMs SIM1 and SIM2. All the protocols of the stack may be realized by appropriate operation of various blocks shown in  FIG. 3 , as will be apparent to a skilled practitioner based on the disclosure provided herein. 
     The various layers in the respective stacks may be implemented to generally conform to the ISO OSI (International Standards Organization Open Systems Interconnect) model, and are only briefly described below, since the corresponding implementations of the blocks would be well known to one skilled in the relevant arts on reading the disclosure herein. Further, only the relevant blocks of the protocol stack are shown in  FIG. 4 , and typically more blocks (such as transport layer etc.) according to the ISO OSI model may be present, as also would be apparent to one skilled in the relevant arts. Although it is assumed herein that UE  120  is implemented to have separate stacks for each of the two SIMs, a single/same protocol stack may also be designed to handle operations for both SIMs. Arbitration block  480  is also shown in  FIG. 4 . 
     Protocol stack  400 B, which is assumed to handle operations for SIM2  360 B, is shown containing layers L1, L2, L3 and the application layer. Layer 1 corresponds to PHY  410 , which represents the electrical and physical interface between UE  120  and a transmission medium (here a wireless medium). PHY  410  contains RX block  380 A, RX block  380 B and TX block  370 . The portion of PHY  410  that contains RX block  380 A is assumed to be part of protocol stack  400 A, while the portion that contains RX block  380 B is assumed to be part of protocol stack  400 B. The TX block  370  of PHY  410  is deemed to be part of both protocol stacks  400 A and  400 B. Whether TX block  370  (transmit portion) of PHY  410  operates for transmitting signals corresponding to SIM1 or SIM2 is controlled by arbitration block  480  (such control being effected via path  481 , and which corresponds to path  317  of  FIG. 3 ). 
     The transmit portion of PHY  410  receives data from either MAC  420 A or MAC  420 B (depending on control from arbitration block  480 ) and forwards the data to antenna  395  for transmission. RX block  380 A-portion of PHY  410  receives data from antenna  395  and forwards the data to MAC  420 A for further processing. RX block  380 B-portion of PHY  410  receives data from antenna  396  and forwards the data to MAC  420 A for further processing. 
     Layer 2 of protocol stack  400 B includes MAC (Medium Access Control layer)  420 B, Radio Link Control layer (RLC)  430 B and Packet Data Convergence Protocol (PDCP)  440 B. MAC  420 B performs operations such as mapping between logical channels and transport channels, error correction through HARQ, priority handling between logical channels, etc. RLC  430 B performs operations such as error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, duplicate detection, etc. PDCP  440 B performs operations such as header compression and decompression, ciphering and deciphering, etc. 
     Layer 3 of protocol stack  400 B includes RRC (Radio Resource Control layer)  450 B and NAS (Non-access Stratum protocol)  460 B. RRC  450 B performs operations such as paging, establishment, maintenance and release of an RRC connection between UE  120  and base station  140  ( FIG. 1 ), security functions including key management, QoS (Quality of Service) management functions, measurement reporting and control of the reporting, etc. RRC  450 B maintains data structures representing various operational states (e.g., whether SIM2 is in RRC idle mode or RRC connected mode, whether measurement request has been received from eNodeB  140 , whether a VoLTE (Voice over LTE) call is currently underway, etc), some of which are shown and described below with respect to  FIG. 6 . NAS  460 B performs operations such as support of mobility of UE  120 , support of session management procedures to establish and maintain IP connectivity between UE  120  and a packet data network gateway, etc. 
     Application layer  470 B represents a communications component that allows software applications executing in UE  120 , and associated with SIM2, to communicate with software applications in other nodes (servers, etc.) via the other blocks shown in  FIG. 4 . 
     MAC  420 A, RLC  430 A, PDCP  440 A, RRC  450 A, NAS  460 A and application layer  470 A operate similar to MAC  420 B, RLC  430 B, PDCP  440 B, RRC  450 B, NAS  460 B and application layer  470 B described above, but correspond to SIM1. Specifically, RRC  450 A maintains data structures representing various operational states (e.g., whether SIM1 is in RRC idle mode or RRC connected mode, whether measurement request has been received from eNodeB  130 , whether a VoLTE (Voice over LTE) call is currently underway, etc), some of which are shown and described below with respect to  FIG. 6 . 
     Arbitration block  480  (which represents a software module executed by processing block  310 ) retrieves various state parameters from RRC  450 A and RRC  450 B, and thus determines the activity state of both SIMs. According to an aspect of the present disclosure, arbitration block  480  allows one SIM (e.g., SIM2) to transmit measurement results (in response to a measurement request) only if there is no call ongoing in the other SIM (e.g., SIM1), as described next with combined reference to  FIG. 5  and  FIG. 6 . Merely for illustration, it is assumed in the description below that each of SIM1 and SIM2 (as well as UE  120 ) is designed for access to corresponding LTE networks. 
     5. Example Scenario 
     According to an aspect of the present disclosure, both SIM1 and SIM2 of UE  120  are designed for accessing LTE services. It is assumed that a paging message is received on SIM2 while a VoLTE (Voice over LTE) call is ongoing on SIM1. The paging message on SIM2 is an indication that there is an incoming VoLTE call or an SMS (Short Messaging Service) on SIM2. The measurement request on SIM2 of UE  120  (as noted in step  210  of the flowchart of  FIG. 2 ) is received at some time instant following the paging message, and is received as part of an RRC Connection Reconfiguration message that encapsulates a measurement request on SIM2. The events of the example scenario, including the exchange of messages between UE  120  and eNodeB  140  and the operation of arbitration block  480 , are described below with combined reference to  FIGS. 5A-5D  and  FIG. 6 . 
       FIGS. 5A-5D  show the entries of a table  500  containing status of various state parameters for SIM1 and SIM2 retrieved by arbitration block  480  from RRC  450 A and RRC  450 B, and stored in RAM  340  or non-volatile memory  320 . Column C1 lists various state parameters related to call related procedures corresponding to SIM1 and SIM2, and columns C2 and C3 respectively list the corresponding status (Yes or No) for SIM1 and SIM2. Row R1 contains the status of whether a paging message has been received. Row R2 contains the status of whether an RRC connection has been established. Row R3 contains the status of whether a default radio bearer connection has been established. Row R4 contains the status of whether an RRC connection reconfiguration message has been received (with the message containing a measurement request) from the corresponding base station. Row R5 contains the status of whether a VoLTE call is ongoing currently. 
     In  FIG. 5A , the entries in rows R2, R3 and R5 corresponding to SIM1 are all shown as ‘Yes’, reflecting the situation that a VoLTE call is currently ongoing in SIM1. The entries corresponding to row R1 and R4 for SIM1 are shown with an ‘X’, indicating that these are ‘don&#39;t care conditions, and the entries could be either Yes or No. 
       FIG. 6  is a message sequence diagram illustrating the sequence of messages that are exchanged between UE  120  and eNodeB  140 . For illustration, it is assumed that a call is ongoing on SIM1 at least in the duration t 6001  to t 6010 . Prior to time instant t 6001 , SIM2 of UE  120  is in an RRC Idle state after attaching with internet packet data network (PDN) and registering with IMS (IP Multimedia Subsystem) PDN via eNodeB  140  ( 601 ). RRC Idle state indicates that SIM2 is not connected to eNodeB  140  (no radio link), although eNodeB  140  (or the corresponding mobile network) knows that the SIM2 of UE  120  is present on the network and is able to reach it in case of an incoming call or SMS. 
     At time instant t 6001 , SIM2 receives a paging message ( 602 ) from eNodeB  140 . RRC  450 B stores a state variable to reflect such condition (Yes), and the status retrieved by arbitration block  480  and stored in table  500  (as shown in  FIG. 5A ) is accordingly indicated as ‘Yes’ in row R1/column C3. 
     In response to receipt of paging message  602 , and at t 6002 , UE  120  transmits, on SIM2, a service request/RRC connection request ( 603 ) to eNodeB  140 . Service request is generally generated by NAS  460 B and may be piggy-backed on the RRC connection request generated by RRC  450 B. An RRC connection is then established between UE  120  (SIM2) and eNodeB  140 . Although not shown in  FIG. 6 , the RRC connection may entail exchange of ‘RRC connection setup’ message and ‘RRC connection setup complete message’ between UE  120  and eNodeB  140 . 
     Once the RRC connection is thus setup, RRC  450 B stores a state variable to reflect RRC connection established condition as ‘Yes’, and the status retrieved by arbitration block  480  and stored in table  500  (as shown in  FIG. 5B ) is accordingly indicated as ‘Yes’ in row R2/column C3. 
     At t 6003 , eNodeB  140  transmits an RRC connection reconfiguration message ( 604 ) to UE  120 , with the message encapsulating a trigger for measurement request. The RRC connection reconfiguration message ( 604 ) is a command from eNodeB  140  to modify the RRC connection established following the establishment of an RRC connection between SIM2 and eNodeB  140 . RRC  450 B stores a state variable to reflect ‘RRC connection reconfiguration message received’ as ‘Yes’, and the status retrieved by arbitration block  480  and stored in table  500  (as shown in  FIG. 5C ) is accordingly indicated as ‘Yes’ in row R4/column C3. 
     The RRC connection reconfiguration message is aimed at (among other purposes) establishing radio bearers to connect UE  120  to a target device. In particular, and as relevant to aspects of the present disclosure, the RRC connection reconfiguration message  604  encapsulates (i.e., contains in its payload) one or more measurement objects. The measurement objects include commands from eNodeB  140  to UE  120  to perform one or more measurements, and to transmit to eNodeB  140  the measurement results, when corresponding conditions are met and/or as the context requires. 
     As an example, a measurement object may correspond to a request for measurement of signal quality in a neighboring cell (with respect to the current serving cell of eNodeB  140 ) in the event the carrier signal quality in the current serving cell (of eNodeB  140 ) falls below a predetermined threshold. As another example, a measurement object may correspond to a request for measurement of a carrier signal in an adjacent cell (termed a secondary cell) to enable carrier aggregation. Alternatively, or in addition, the request may be for signal quality of carriers used by an access point (AP) in a nearby WLAN (Wireless Local Area Network) for LWA (LTE WiFi Carrier Aggregation). Such measurements requests may be aimed at enabling carrier aggregation to enable higher data throughput between UE  120  (on SIM2) and a corresponding device. Another example is a measurement object corresponding to a request for measurement of carrier signal quality in nearby cells to enable eNodeB  140  in determining which other cell to handover UE  120  to (when UE  120  is moving). 
     However, according to an aspect of the present disclosure, UE  120  does not respond to any measurement objects (which may, in general, be viewed as measurement requests) in the RRC reconfiguration message ( 604 ). That is, UE  120  may not perform any measurements (noted above), and does not transmit any results of the measurements to eNodeB  140  (even if such measurements are made). In particular, arbitration block  480  checks the corresponding entries (specifically R5/C2) of table  500  to determine if a VoLTE call is ongoing in SIM1. Since a VoLTE call is ongoing in SIM1, arbitration block instructs RRC  450 B not to perform any measurements or to transmit any measurement results (noted in  FIG. 6  as state  605 ), and does not allocate the transmit chain to SIM2. As a result, SIM2 does not perform any measurements or transmit any measurement results. Therefore, any disruption to the ongoing VoLTE call on SIM1 that might otherwise have happened (if the shared transmit chain is allocated to SIM2 to send measurement results) is avoided. 
     Between t 6004  and t 6005 , a default bearer is reconfigured for SIP (Session Initiation Protocol) signaling ( 606 ). SIP protocol is described in detail in RFC 3261 published by the Internet Engineering Task Force (IETF). RRC  450 B stores a state variable to reflect ‘default radio bearer established’ condition as ‘Yes’, and the status retrieved by arbitration block  480  and stored in table  500  (as shown in  FIG. 5D ) is accordingly indicated as ‘Yes’ in row R3/column C3. 
     At t 6006 , eNodeB  140  transmits a SIP: INVITE message (assuming the paging message  602  was in response to a request by another device for a VoLTE call with SIM2 of UE  120 ) or a SIP:MESSAGE (assuming the paging message  602  was in response to an SMS message waiting to be transmitted to SIM2 of UE  120 ), as indicated by message  607 . 
     In interval t 6007 -t 6008 , IMS client (here SIM2 of UE  120 ) extracts the caller-ID of the originator of the VoLTE call intended for SIM2 from the SIP: INVITE message, assuming that the paging message ( 602 ) was for VoLTE call, as indicated in message  608 . If the paging message  602  was for an SMS, SIM2 extracts the caller-ID of the originator of the SMS from the SIP: MESSAGE containing the text in the SMS over LTE. 
     At t 6009 , UE  120  transmits either a SIP: REJECT message (if the paging message  602  was for a VoLTE call) or a “200 OK” message (if the paging message  602  was for an SMS), as indicated by message  609 . 
     Having thus extracted the caller-ID (which was a reason for responding to paging request  602 ), UE  120  transmits, at t 6010 , an RRC connection release message ( 610 ), and the RRC connection between UE  120  and eNodeB  140  is disconnected. 
     Thus, UE  120  is able to obtain the caller-ID of the originator of a VoLTE call or SMS without performing any measurements or transmitting the measurement results, and thereby without disrupting the ongoing VoLTE call on SIM1. UE  120  may operate similarly if there had been an ongoing VoLTE call on SIM2 when a measurement request is received on SIM1. 
     Thus, disruption of an ongoing call is prevented, as well as potential power savings (by not performing measurements or transmitting the measurement results) obtained by operating UE  120  in the manner noted above, when multiple SIMs share a same transmit chain. It is noted here that had UE  120  performed the measurements and transmitted the results, eNodeB  140  could potentially have responded with a WT (WLAN termination) Add request or SCell (secondary cell) Add request to enable carrier aggregation. Such ADD requests would have required UE  120  to transmit corresponding responses, and thereby further disrupt the ongoing VoLTE call on SIM1, with the possibility of the VoLTE call on SIM even being dropped. By not sending any measurement results at all, UE  120  prevents further requirement of use of the transmit chain for SIM2 when a VoLTE call is ongoing on SIM1. 
     If a VoLTE call had not been ongoing in SIM1, then arbitration block  480  would have responded to the measurement requests on SIM2 by making the measurements of carrier signals (of neighboring cells, other bands in the same cell (i.e., cell served by eNodeB  140 ), and/or APs of nearby WLANs. UE  120  would then have transmitted the measurement results (indicating the frequency bands, cells or APs that have acceptable signal quality) using the shared transmit chain, and responded to further requests such as adding a secondary cell, etc., to enable carrier aggregation (whereby SIM2 receives data units additionally (i.e., in parallel to those received via eNodeB  140 ) via the frequency bands/cell/APs indicated as having good carrier signal quality), and/or handover to a different cell served by the network operator corresponding to SIM2. Thus, if UE  120  is moving, and the measurement response by UE  120  indicates that a neighbor cell of the cell served by eNodeB  140  has acceptable signal quality, SIM2 may receive data from eNodeB  140  indicating that SIM2 has been handed over to such neighbor cell or base station. 
     6. Conclusion with Examples 
     References throughout this specification to “one aspect of the present disclosure”, “an aspect of the present disclosure”, or similar language means that a particular feature, structure, or characteristic described in connection with the aspect of the present disclosure is included in at least one aspect of the present disclosure. Thus, appearances of the phrases “in one aspect of the present disclosure”, “in an aspect of the present disclosure” and similar language throughout this specification may, but do not necessarily, all refer to the same aspect of the present disclosure. 
     Thus Example 1 may correspond to a wireless device with two holders for housing respective SIMs. The wireless device may also contain a processing block for executing instructions which cause the wireless device to receive a first request on the second SIM to measure a signal quality at a location of the wireless device. The wireless device sends a response to the first request only if there is no call ongoing on the first SIM. 
     In example 2, the wireless device of example 1 can optionally maintain status data indicating whether any calls are ongoing in any of a set of SIMs provided on the wireless device, and the status data may be examined to determine whether any call is ongoing on the first SIM. 
     In example 3, the wireless device of any of examples 1 and 2 may contain a transceiver with a common transmission chain shared by both of the first SIM and the second SIM. In such an example, the second SIM receives a paging request to setup a second call, with the first request being received following the paging request. The wireless device communicates with the base station (from which both of the first request and the paging request are received) to extract a caller-ID of a calling station which caused the base station to send the paging request. The wireless device disconnects the second call soon after extracting the caller-ID. 
     In example 4, the wireless device of any of examples 1, 2 and 3, is assumed to be physically located in a location covered by a first cell of a first base station, and the response indicates a first set of frequency bands as having acceptable signal quality. The wireless device may thereafter receive additional data units using the first set of frequency bands. Such a feature may support carrier aggregation (for higher bandwidth) or switching to a different cell with stronger carrier signals at that location. 
     In example 5, the wireless device of any of examples 1, 2, 3 and 4, conducts a VoLTE call on SIM1 (as the ongoing call) and receives the paging request to transfer a SMS (short messaging service) on SIM2. The wireless device extracts the SMS from the calling station, with the caller-ID being contained in the SMS message. 
     The features of the above examples are also shown as implemented as respective methods, and also as a computer readable medium storing instructions which upon execution causes the above noted features to be operative. 
     While various aspects of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described aspects, but should be defined only in accordance with the following claims and their equivalents.

Metadata:
Filing Date: 20190821
Publication Date: 20201103
Grant Date: 20201103
Priority Date: 20160930
Inventors: SAXENA, ALOK
DEV, Rishav
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/542", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/183", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W24/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/183", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/0066", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/183", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0066", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/085", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 61757406