PRIORITY APPLICATION

[001] This application claims the benefit of priority to India Application No. 201641042578, filed 14 December 2016, which is incorporated herein by reference in its entirety.

Background

[002] Technical Field

[003] Aspects of the present disclosure relate generally to wireless mobile devices, and more specifically to communication operations in multi-SIM wireless devices.

[004] Related Art

[005] Wireless devices such as mobile phones are widely used for communicating signals representing voice, data, text, video, etc., to/from cellular networks. Wirelesses devices are often equipped with multiple subscriber identity modules (SIMs), for example, when the same wireless device is to be used by two subscribers (even if the two subscribers correspond to the same person). Aspects of the present disclosure relate to communication operations in such multi-SIM wireless devices.

Brief Description of the views of Drawings

[006] Example aspects of the present disclosure will be described with reference to the accompanying drawings briefly described below.

[007] Figure 1A is a block diagram of an example environment in which several aspects of the present disclosure can be implemented.

[008] Figure IB is a block diagram showing more details of a wireless device (WD) of the example block diagram of Figure 1 A, according to an aspect of the present disclosure.

[009] Figure 2A is a flowchart illustrating an exemplary manner in which uplink data from one of a pair of SIMs is handled by a WD, according to an aspect of the present disclosure.

[010] Figure 2B is a flowchart illustrating an exemplary manner in which downlink data for one of a pair of SIMs is handled by a WD, according to an aspect of the present disclosure.

[011] Figure 3 a block diagram representing an exemplary wireless device (WD) in which several aspects of the present disclosure can be implemented.

[012] Figure 4 is a block diagram illustrating an exemplary manner in which packets associated with a pair of SIMs are handled, according to an aspect of the present disclosure.

[013] Figure 5 is a timing sequence illustrating an exemplary sequence of operations involved in operating one SIM as a remoteUE in a WD with multiple SIMs, according to an aspect of the present disclosure.

[014] Figure 6 is a timing diagram showing exemplary transmissions from a WD for a pair of SIMs, according to an aspect of the present disclosure.

[015] 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

[016] 1. Overview

[017] According to an aspect of the present disclosure, a wireless device generates packets for a subscriber specified by a first SIM and transmits the formed packets using a second SIM. According to another aspect, the wireless device receives packets destined for the second SIM on a wireless medium according to a wireless communication network standard, and forwards at least some of the data in the packet to the subscriber specified by the first SIM.

[018] Several aspects of the present 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 invention. One skilled in the relevant arts, however, will readily recognize that the invention 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 disclosure.

[019] 2. Example Environment

[020] Figure 1A is a block diagram representing an exemplary 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 contain more systems/devices. Figure 1A shows a cell 100 comprises base station (BS) 110 and wireless device (WD) 120, 130 and 140.

[021] In the context of LTE (Long Term Evolution), BS 110 is referred to as an eNodeB. The term 'base station' as used herein covers base stations as well as eNodeBs. Further, although noted as covering corresponding normal cell areas, BS 110 can also be designed to cover a much smaller area such as, for example, a macrocell, a microcell, a picocell, a femtocell, a home eNodeB, small cell as well. Macro/micro/femtocells/picocells/home eNodeB 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.

[022] WDs 120, 130 and 140 represent example user equipment (UE) such as mobile phones, tablets, vehicles, mobile devices, personal computers, etc., and may be used for wireless communication such as voice calls, data services such as web browsing, receiving and sending emails, etc., and are all serviced by BS 110. The area representing cell 100 may include other UEs serviced by other base stations, but not shown in Figure 1A in the interest of simplicity. In a common scenario, a UE (or a wireless device/WD in general) interfaces with a base station of a mobile cellular network providing the corresponding user the facility of voice and data based services. From the perspective of the mobile network, the user is referred to as a subscriber and generally has a unique identity/ account with the mobile cellular network operator.

[023] BS 110 is a fixed communications unit of a mobile network deployed by a cellular network operator and provides the last-mile (or last hop) communications link to wireless devices, that are within communications range (i.e., within the coverage area) of BS 110. BS 110 has a coverage area represented by cell 100. Although not shown in Figure 1A, BS 110 may be connected to other devices/systems in the corresponding wireless network infrastructure to enable UEs in coverage range to communicate with devices (e.g., other UEs), with landline communications equipment in a conventional PSTN (Public Switched Telephone Network), public data networks such as the internet etc.

[024] BS 110 and WDs (120, 130 and 140) within cell 100 may operate according to any of cellular network standards/specifications for wireless mobile communications such as, for example, GSM (Global System for Mobile Communications), LTE (Long Term Evolution, including frequency division duplex (FDD) and/or time division duplex (TDD) modes), UMTS (Universal Mobile Telecommunications System), CDMA (Code Division Multiple Access), W- CDMA (Wideband CDMA), 5G, etc.

[025] According to an aspect of the present disclosure, one or more of WDs 120, 130 and 140 are multi-SIM devices, with each SIM configured to represent a corresponding subscriber. For example WD 120 is a multi-SIM device, and is shown in Figure IB as containing two SIMs, namely SIMl (111) and SIM2 (112). Other UEs are not shown in Figure IB in the interest of clarity. Wireless communication between WD 120 and BS 110 is indicated by double-sided arrow 121, which represents an over-the-air transmission path (wireless path). Path 115 indicates the communication between the hardware and software components operational to support the two SIMs. WD 120 may contain more SIMs also, though not shown. Although several aspects of the present disclosure can be directed in general to a WD with multiple SIMs, to simplify description, the description below assumes that the WD has only two SIMs. [026] In one prior approach, the scheduling of sending (transmitting) from each of the two SIMs is generally not coordinated, and as a result the corresponding transmissions can occur in overlapping time intervals. Support for such overlapping (or simultaneous) transmissions for the two SIMs (from two corresponding transmitters) may present problems. One problem is that the maximum (instantaneous) transmit power that WD 120 is permitted to use may be subject to a limit. For example, clause 6.2.2 of 36.101 3GPP (3 ^rd Generation Partnership Project) specification, restricts the maximum output power of a WD to 23dBm +2dB measured over at least 1ms.

[027] One way of overcoming such transmit power limit is for WD 120 to reduce the transmit power of one or both of the two transmitters, so that the total transmit power (sum of powers of the two transmitters) lies within the maximum limit. Such transmit power reduction may, however, degrade the signal quality and/or range for the SIM(s) whose transmit power has been reduced.

[028] Another problem is one of limited number of transmitters and receivers in WD 120. To support multiple simultaneously-executing applications and/or other operations such as making neighbor-channel measurements, WD 120 may, at least at times, need to share a same transmitter and/or receiver for transmission and reception for the two SIMs. Such sharing may translate to interruptions in the transmission and/or reception for one SIM, when the shared transmitter/ receiver is being used for the other SIM.

[029] Yet another problem is restriction in the specific frequency bands that transmitters and receivers of WD 120 can operate in, even when multiple transmitters and receivers are present in WD 120. To illustrate, one SIM may require transmissions in frequency band A, while the other SIM may require transmissions in frequency band B. However, WD 120 may be designed such that transmitters in WD 120 can operate only in one of the two bands A and B. A similar problem might present itself for reception as well.

[030] Several aspects of the present disclosure can overcome one or more of the problems noted above, as described next.

[031] 3. Communication Operations in a Dual-SIM WD

[032] Figures 2A and 2B are exemplary flowcharts illustrating the manner in which communication operations are performed in a dual-SIM WD, according to aspects of the present disclosure. Figure 2A illustrates the manner in which uplink data from one of the two SIMs is handled by WD 120, while Figure 2B illustrates the manner in which downlink data for one of the two SIMs is handled. The flowcharts are described with respect to WD 120 of Figure 1A, 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 of Figure 2A starts in step 201, in which control passes immediately to step 210.

[033] In step 210, WD 120 generates a packet for a first subscriber specified by a first SIM. As used in the description herein, the first SIM corresponds to SIMl (111), which would store a unique identification number identifying a subscriber (e.g., International Mobile Subscriber Identity (IMSI) number or commonly referred to as a phone number). Forming a packet for such a subscriber implies that the packet contains data corresponding to services serving the first subscriber. Such services may include voice calls (packet-switched and/or circuit switched) and data transfer forming the basis for various applications (e.g., web browsing, receiving and sending emails, video, mobile applications related information, etc.). Control then passes to step 220.

[034] In step 220, WD 120 transmits the packet (formed in step 210) using a second SIM specifying a second subscriber. The second SIM corresponds to SIM2 (112), which is assumed to store a corresponding unique identifier for a second subscriber (different from the first subscriber noted above, even if both subscribers refer to the same person). The packet is transmitted using the second SIM, implying that the packet transmitted on the wireless medium (in cell 100) has transmission characteristics indicating that the packet originated on behalf of the subscriber of the second SIM in accordance with the cellular wireless standard (E.g., LTE). Control then passes to step 249, in which the flowchart ends.

[035] Thus, WD 120 serves a subscriber specified by the first SIM by transmitting packets associated with the first SIM using the second SIM. To illustrate with an example, assuming a video needs to be downloaded for SIMl, WD 120 would forward the request for the video download using SIM2 to BS 120. The request would contain a suitable mechanism for indicating to BS 110 that the video data is for the subscriber of SIMl (rather than that of SIM2), as described in sections below with examples. Logical path 115 of Figure IB symbolically represents that the application(s) generating the packet (formed in step 210) for SIMl transfer the packet to corresponding application(s) executing for SIM2. Example implementation details of such a symbolic communication path are noted in sections below.

[036] With respect to Figure 2B, the flowchart starts in step 251, in which control passes immediately to step 260.

[037] In step 260, WD 120 receives a packet destined to a second SIM according to a wireless network standard. The second SIM refers to SIM2 (112). The electrical and protocol characteristics of the packet are according to a wireless network standard, such as, for example LTE. The packet being 'destined' to the second SIM according to the cellular network standard implies that the packet contains information that indicates to the second SIM to receive and process the packet. The packet also contains additional information according to a suitable convention to indicate that the packet is for consumption by a first SIM, as noted in sections below with corresponding examples. Control then passes to step 270.

[038] In step 270, WD 120 forwards the packet to a first subscriber specified by a first SIM. The first SIM and first subscriber are the same as noted above with respect to the flowchart of Figure 2 A. WD 120 determines that the packet needs to be forwarded to the first SIM by inspecting corresponding field entry according to a suitable convention, as noted in sections below. Control then passes to step 299, in which the flowchart ends.

[039] Thus, WD 120 receives and transmits downlink and uplink data respectively for SIM1 using SIM2. In addition, WD 120 may transmit/receive uplink/downlink data for SIM2 in the conventional manner in which a single-SIM WD would operate according to corresponding cellular network standards. In an aspect, both the first SIM and the second SIM are designed to subscribe to services from a same operator and are serviced by the same base station (BS 110 of cell 100). However, according to another aspect, the first SIM can subscribe to a first service provider via a first cell, while the second SIM can subscribe to a second (different) service provider via the first cell or via another cell.

[040] According to an aspect of the present disclosure, WD 120 may perform the operations noted above with respect to the flowcharts of Figure 2A and Figure 2B only when one or more conditions are satisfied.

[041] One condition for WD 120 to transmit the first packet (generated for the first subscriber) using the second SIM is satisfied when WD 120 is already transmitting packets using the second SIM, and determines that transmission of the first packet using the first SIM at a power level requested by the base station corresponding to the first SIM would result in the total transmitted power (for first SIM and second SIM simultaneously) exceeding the maximum (instantaneous) transmit power allowed for WD 120.

[042] Specifically, it may be appreciated that base station 110 specifies the transmit power level for each connection (SIM Card). Thus, if there is an active transmission/connection already on the second SIM (with packets being transmitted at a second power level) and if a new connection is required to be established for the subscriber specified by the first SIM at a first power level (as specified by the base station for the new connection), WD 120 determines whether the sum of the first power level and the second power level exceeds a pre-specified threshold (e.g., maximum power rating of WD 120 or maximum transmit power allowed per device). Only when the threshold is exceeded, the packets may be transmitted/received in accordance with Figures 2A and 2B. [043] Another condition for WD 120 to transmit the first packet using the second SIM is satisfied if WD 120 determines that transmission of the first packet using the first SIM is required (based on such indication by the corresponding base station) to be in a frequency band that is not supported by any of the transmitters in WD 120.

[044] Operation by WD 120 according to the flowchart of Figure 2B may also be based on certain conditions, one of which is when WD 120 determines that reception of packets for the first SIM is specified by the corresponding base station to be in a frequency band that is not supported by any of the receivers in WD 120.

[045] Thus, the sidelink communication between SIM1 and SIM2 may be performed only upon the relevant condition(s) as noted above are satisfied. Once the relevant condition is satisfied, WD 120 may maintain such mode/technique of communication until the relevant condition(s) are no longer satisfied.

[046] When the conditions are not satisfied, WD 120 may use one pair of transmitter and receiver for transmissions and receptions for SIM1 and another pair of transmitter and receiver for transmissions and receptions for SIM2, rather than employ the sidelink technique.

[047] According to an aspect, operation according to the flowcharts of Figure 2A and Figure 2B for transmitting and receiving data for SIM1 by using SIM2 is achieved by treating one SIM (e.g., SIM1) as being the equivalent of a remoteUE and the other SIM (e.g., SIM2) as being equivalent of a relayUE according to the device-to-device (D2) mode of operation as specified in wireless communication network standards, for example section 5.10 (Sidelink) of Release 13 of 3GPP (3 ^rd Generation Partnership Project) technical specification document TS 36.331 V13.1.0 (2016-03). Accordingly, communication on symbolic path 115 (Figure IB) is termed sidelink communication. References to the term relaySIM herein refer to hardware/software units/modules that are operative to process data corresponding to SIM2, while references to the term remoteSIM herein refer to hardware/software units/modules that are operative to process data corresponding to SIM1.

[048] According to the specification noted above, WD 120 indicates to BS 110 that one of the two SIMs (e.g., SIM1) will be operated as the remoteUE, while the other SIM (e.g., SIM2) will be operated as a relayUE. Due to such an operation, uplink and downlink data for the two SIMs get scheduled by a same BS (BS 110) through SIM2 referred to as relayUE herein. As a result, only one transmitter of WD 120 will have to be operated (to transmit) to accommodate both SIMs data, with the result that the transmitter can be operated at the maximum power permitted by the applicable technology/standard.

[049] Another benefit of the above approach is that only one transmitter and one receiver may be required in WD 120 to support both of SIM1 and SIM2, since BS 110 schedules transmissions to, and expects transmission from, only one of the SIMs, SIM2 (relayUE) in this case.

[050] Yet another benefit is that the transmitter in WD 120 now needs to be able to operate only in a limited number of frequency bands, namely the bands in which communication between SIM2 and BS 110 needs to take place.

[051] The description is continued with an illustration of example implementation details of WD 120.

[052] 4. Wireless Device

[053] Figure 3 is a block diagram representing an example wireless device (WD) in which several aspects of the present disclosure can be implemented. WD 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 module 360A, SIM2 module 360B, transmit (Tx) block 370, receive (Rx) block 380, switch 390, and antenna 395. The combination of processing block (or circuitry) 310, non- volatile memory 320, input/output (I/O) block 330, random access memory (RAM) 340, real-time clock (RTC) 350, Tx block 370 and Rx block 380 may be implemented in integrated circuit (IC) form.

[054] Some or all units of WD 120 may be powered by a battery (not shown). In another aspect of the present disclosure, WD 120 is mains-powered and contains corresponding components such regulators, filters, etc. The specific blocks of WD 120 are shown by way of illustration only, and WD 120 may contain more or fewer blocks depending on specific requirements. In an aspect of the present disclosure, WD 120 corresponds to a mobile phone supporting dual-SIM.

[055] Furthermore, it is assumed herein that the two SIMs share a same receiver (Rx Block 380) and a same transmitter (Tx Block 370). However, WD 120 may contain other receivers and transmitters also. When such additional transmitters and receivers are present, one set of transmitter and receiver may be dedicated for use by one SIM, while another set of transmitter and receiver may be dedicated for use by the second SIM. However, even when such multiple transmitter/receiver sets are available, WD 120 may still share a same transmitter/receiver set for transmissions/receptions for both SIMs.

[056] Each of SIM1 module 360A and SIM2 module 360B is designed to identify the specific subscribers and related parameters to facilitate the subscriber to access various services provided via the wireless communication network. In an embodiment, each module contains a physical holder (into which a SIM card can be inserted) and electrical/electronic circuits which together retrieve various data parameters stored on the inserted SIM cards. SIM card (or simply SIM1) (111) is inserted in SIM1 module 360A, and SIM2 112 is inserted in SIM2 module 360B. A SIM card may provide the international mobile subscriber identity (IMSI) number (also the phone number) used by a network operator to identify and authenticate a subscriber.

[057] Typically, the SIM is 'inserted' into such holder before wireless device 120 can access the services provided by the network operator for the subscriber configured on the SIM. 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 network operator, etc. However, in alternative embodiments, 'virtual SIMs' can be used instead of physical SIM cards, and each SIM module may accordingly be implemented to support virtual SIMs. In yet another alternative embodiment, a physical SIM may be supported in combination with one or more virtual SIMs within the wireless device. The modules may be implemented to support such alternative embodiments as well.

[058] Processing block 310 may read the IMSI number, security keys etc., in transmitting and receiving voice/data via Tx block 370 and Rx block 380 respectively. SIM1 and SIM2 may subscribe to data and voice services according to one of several radio access technologies such as GSM, LTE (FDD as well as TDD), CDMA, WCDMA, 5G, etc., as also noted above. Further, the type of radio access technology available to the two SIMs can be the same (e.g., LTE on both SIMs), or different (e.g., LTE on one SIM and 3G on the other SIM, LTE on one SIM and CDMA on the other SIM, etc.).

[059] 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 WD 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.

[060] 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 as desired, depending on whether transmission or reception of wireless signals is required. Switch 390, antenna 395 and the corresponding connections of Figure 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.

[061] Tx block 370 receives, from processing block 310, digital signals representing information (voice, 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).

[062] Rx block 380 represents a receiver that receives a wireless (RF) signal bearing voice/data and/or control information via switch 390, and antenna 395, demodulates the RF signal, and provides the extracted voice/data or control information to processing block 310. Rx block 380 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 block 380 (the receive chain) may contain only the RF circuitry, with processing block 310 performing the baseband operations in conjunction with the RF circuitry.

[063] Although only, one transmitter (Tx block 370) and one receiver (Rx block 380) are shown in Figure 3, WD 120 may contain multiple transmitters and receivers, each pair of transmitter and receiver connected to a same antenna or separate antennas. Thus, WD 120 can use one pair of transmitter and receiver for transmission to and reception from a first base station for SIM1, and another pair of transmitter and receiver for transmission to and reception from either the first base station or another base station for SIM2. WD 120 may use such separate pairs of transmitters and receivers for SIM1 and SIM2 if conditions necessary for operation according to flowcharts of Figure 2A and/or Figure 2B are not satisfied.

[064] Non-volatile memory 320 is a non-transitory machine readable medium, and stores instructions, which when executed by processing block 310, causes WD 120 to operate as described herein. In particular, the instructions enable WD 120 to operate as described with respect to the flowcharts of Figures 2A and 2B. The instructions may either be executed directly from non- volatile memory 320 or be copied to RAM 340 for execution.

[065] 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) 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. At least some portion of RAM 340 may be used to serve as a shared memory for the passing of data between remoteSIM and relaySIM. However, it is understood that other techniques for message exchange between remoteSIM and relaySIM are also possible.

[066] Processing block 310 (or processor or processing circuitry in general) may contain multiple processing units internally, with each processing unit potentially being designed for a specific task. Thus, processing block 310 may be implemented as multiple separate processing cores, one each for handling operations required for each of multiple SIMs (e.g., SIM1 and SIM2). Alternatively, processing block 310 may represent a single processing unit executing multiple execution threads in software, each execution thread for handling operations required for a corresponding one of multiple SIMs. In the description below, when relaySIM and remoteSIM are noted as performing actions, such reference is to the corresponding processing core or execution thread, as also noted above. In general, processing block 310 executes instructions stored in non-volatile memory 320 or RAM 340 to enable WD 120 to operate according to several aspects of the present disclosure, described in detail herein.

[067] Figure 4 illustrates the manner in which packets corresponding to SIM1 and SIM2 are processed, according to an aspect of the present disclosure. In Figure 4, applications (Subscriber- 1 -Applications 41 OA) executing for the subscriber of SIM1 send/receive data on path 412A to/from SIMl-Packet_Handler 420A. SIMl-Packet_Handler 420A forms one or more IP packets from data received on path 412A, formats the IP packets into portions of time for transmission, for example, sub-frames according to the corresponding wireless network standard (e.g., LTE), and forwards the sub-frames to Tx Block 370 for transmission on a wireless medium.

[068] SIMl-Packet_Handler 420 A receives sub-frames from Rx Block 380, and extracts one or more IP packets in the sub-frames, and forwards the extracted IP packets to Subscriber- 1- applications 410A.

[069] Thus, in this example, block 420 A may be viewed as performing the functions of layer 3 and layer 2 components of the protocol stack corresponding to SIM1. Layer 3 component may include RRC (Radio Resource Control layer) and IP (Internet Protocol layer), and layer 2 component may include MAC (Medium Access Control layer), Radio Link Control layer (RLC) and Packet Data Convergence Protocol (PDCP). However, other layers may be used for implementing above functions.

[070] Subcriber-2 applications 410B and SIM2-Packet_Handler 420B operate similar to Subcriber-1 applications 41 OA and SIM2-Packet_Handler 420 A, except that they correspond to SIM2. Packet handlers 420A and 420B may be realized in the form of software instructions executed by processing block 310.

[071] In conventional operation of WD 120, SIMl-Packet_Handler 420A is operative for transmissions/receptions for subscriber of SIM1, while SIM2-Packet_Handler 420B is operative for transmissions/receptions for subscriber of SIM2.

[072] When operating according to aspects of the present disclosure, data from/to Subscriber- 1- applications 410A are sent/received on path 450 (which corresponds to path 115 of Figure IB) to/from SIM2-Packet_handler 420B, which operates instead of SIM 1 -Packet handler 420A in the manner described in detail herein. [073] Blocks 420A and 420B may be realized by corresponding processing cores within processing block 310, or by corresponding execution threads executed by processing block 310. Thus, the data exchange shown symbolically as occurring on path 115 (Figure IB) may be achieved by processing block 310 by operating as noted above. In particular, a user may configure WD 120 by specifying which of the two SIMs is to be the remoteUE and which the relayUE. Alternatively, such information may be hard-coded in the form of instructions in nonvolatile memory 320. According to an aspect, which of the two SIMs is operated as remoteUE and which as relayUE, is based on one or more of Quality of Service (QoS) requirements, data rate achievable, tariff considerations, and radio link conditions.

[074] With respect to QoS conditions and data rate, that SIM which has a less stringent QoS requirement and lower data rate requirement is selected as the remoteSIM, the other SIM being the relaySIM. With respect to tariff considerations, data subscription and D2D subscription plans of the two SIMS may be different, and if so, that SIM with lower tariff (more favorable subscription plans) may be chosen as the relaySIM, the other SIM being the remoteSIM. With respect to radio link conditions, if the two SIMs are connected to different cells (although only one cell 100 and one BS 110 are shown in Figure 1A and IB), the SIM with the lower filtered RSRP(Reference Signal Received Power) can be chosen as remoteUE, and the other as the relayUE.

[075] The manner in which WD 120 sets up the communications for SIMl according to D2D sidelink mechanism, and the subsequent communications to/from SIMl are illustrated next with respect to a timing sequence.

[076] 5. Timing Sequence

[077] Figure 5 is a timing sequence illustrating exemplary sequence of operations involved in operating one SIM as being the equivalent of a remoteUE (as specified in the 3 GPP standard noted above). In the description below, it is assumed that SIMl is operated as the equivalent of a remoteUE, while SIM2 is operated as the equivalent of a relayUE. Accordingly, SIMl is referred to below as remoteSIM, while SIM2 is referred to as relaySIM. It is further assumed that prior to time instant t50, WD 120 designates SIMl as the remoteSIM and SIM2 as the relaySIM. It may be appreciated that the identities of the remoteSIM and relaySIM can also be the reverse, i.e., WD 120 could also have designated SIMl as the relaySIM and SIM2 as the remoteSIM. It is also assumed that the remoteSIM and the relaySIM have been assigned respective ProSe IDs (identifiers of the UEs when involved in sidelink communication).

[078] At time instant t50, relaySIM transmits a 'SidelinkUEinformation' message (510) to BS 110. The SidelinkUEinformation message conforms to the D2D specification in the 3GPP standards document noted above, and includes three parameters. A first parameter is 'destinationlnfoList' , which contains the identity (ProSe ID noted above) of the remoteSIM. A second parameter is UE-Type, which would be set to a logic one to indicate to BS 110 that the SIM that transmitted the message (namely SIM1) is the relay UE. A third parameter is 'commTxResourceReqRelayUC', which contains information regarding the resources (such as for example, time slot, frequency band for transmission/reception of sidelink data, etc.) required for the sidelink communication between the relaySIM and the remoteSIM. Since the sidelink communication between remoteSIM and relaySIM is now internal communication (within WD 120), and not over the air, commTxResourceReqRelayUC is designed to indicate that no LTE resources are required for sidelink communication.

[079] Based on the receipt of the 'SidelinkUEinformation' message, BS 110 creates (and maintains) a mapping between the IP address and the corresponding PRoSelD of remoteSIM, as well as information that remoteSIM is reachable through relaySIM. BS 110 would, according to normal convention, know the IP address and identity of relaySIM. In LTE, the identity of relaySIM is a C-RNTI (Cell Radio Network Temporary Identifier), which is a unique WD identifier allocated by BS 110 to relaySIM.

[080] At t51, BS 110 transmits a message (520) specifying the resources allocated for the sidelink communication between relaySIM and remoteSIM. While such resources are not needed since communication between relaySIM and remoteSIM is now internal to WD 120 (and not over-the- air), BS 110 may still transmit message 520 and allocate the resources. Such resources are not required/used since both SIMs are part of the same wireless device with internal wired communication path. However, the allocation of such resources ensures the implementation conforms to the corresponding standard(s) noted above. Communication can then take place between remoteSIM and wireless devices or UEs in other cells, wired or wireless devices in a public data network such internet, etc., using relaySIM (SIM2).

[081] Accordingly, at t52 downlink (DL) data (530) with remoteSIM as the final recipient is shown as being transmitted from BS 110 to relaySIM. The DL data is contained in an IP (internet Protocol) packet encapsulated in a corresponding sub-frame constructed by BS 110 according to LTE protocols. BS 110 is assumed to have earlier received the IP packet from an external device. The destination IP address in the IP packet indicates to BS 110 that remoteSIM is the target recipient. Since BS 110 knows that remoteSIM is to be reached through relaySIM (in accordance with D2D protocol), BS 110 generates the sub-frame according to LTE specifications and transmits the sub-frame to relaySIM. The CRC (Cyclic Redundancy Check) value of the sub-frame is scrambled by the C-RNTI (Cell Radio Network Temporary Identifier) of relaySIM to form the content of the CRC field of the sub-frame.

[082] RelaySIM decodes the scrambled CRC in the CRC field of the sub-frame using its C-NRTI (same as that used by BS 110 to scramble the CRC noted above) and computes the CRC of the remainder of the sub-frame. If the computed CRC and the decoded CRC match, relaySIM concludes that the sub-frame is meant for processing by relaySIM according to a cellular network standard. Accordingly, relaySIM reads the destination IP address of the encapsulated IP packet in the sub-frame, and determines that the IP packet is targeted to remoteSIM.

[083] Hence, at t53, relaySIM (or specifically SIM2-Packet-Handler 420B) transfers the IP packet via an internal path (450) in WD 120 to remoteSIM. As noted above, such transfer can be achieved, for example, by SIM2-Packet-Handler 420B storing the IP packet in a shared memory (portion of RAM 340) accessible by both the remoteSIM and the relaySIM. The transfer is indicated in Figure 5 as IP packet 531.

[084] When remoteSIM wishes to transmit data to another destination device (which can be, for example, another WD in the same or different cell, or a device in internet), remoteSIM constructs an IP packet with its own IP address in the source IP address field, the IP address of the target device in the destination IP address field, and data as payload, and transfers, at t54, the IP packet (indicated as IP packet 540 in Figure 5) to relaySIM via the shared memory noted above.

[085] RelaySIM receives IP packet 540, determines that the target device for the packet is not itself. Accordingly, relaySIM constructs an LTE sub-frame which contains IP packet 540 embedded within it. RelaySIM requests BS 110 for resources (which include time slot and frequency band) for transmit the sub-frame to BS 110. On receipt of the resources, relaySIM transmits, at t55, the sub-frame (indicated as uplink (UL) data 541 in Figure 5) to BS 110.

[086] RelaySIM may use uplink traffic flow templates to select dedicated uplink bearers assigned for relaying the data to carry UL data 541 to BS 110. As is well known in the relevant arts, the traffic flow template is a set of information that is used to map a service data flows to a specific radio bearer.

[087] BS 110, on receipt of UL data 541, extracts the IP packet in the sub-frame, inspects the destination IP address field in the IP packet, and forwards the IP packet to the next-hop device in the path to the destination device of the IP packets.

[088] Data generated by, and destined to, relaySIM are communicated with BS 110 in the conventional manner specified by the corresponding cellular standards such as LTE.

[089] The transmission and/or reception of packets/sub-frames corresponding to the subscribers of SIMl and SIM2 in the conventional manner as well as according to aspects of the present disclosure are illustrated in Figure 6. In time interval t61-t62, data associated with applications of SIMl are transmitted and received on air (wireless medium) by operation and interaction of blocks 410A and 420A of Figure 4, via path 412A. In interval t61-t62, applications associated with SIM2 are assumed not to be transmitting or receiving any packets. Interval t62-t63 represents an interval in which no frames are transmitted/received by either SIMs.

[090] In time interval t63-t64, data associated with applications of SIM2 are transmitted and received on air (wireless medium) by operation and interaction of blocks 41 OB and 420B of Figure 4, via path 412B. In interval t63-t64, applications associated with SIMl are assumed not to be transmitting or receiving any packets.

[091] However, starting at time instant t64, it is assumed that the application associated with SIMl also start transmitting and receiving packets. Accordingly, SIM2 may cause message 510 of Figure 5 to be sent to cause SIM2 to operate as relaySIM and SIMl to operate as remoteSIM. Accordingly, in time interval t64-t65, data for subscriber of SIMl is sent/received using SIM2 according to aspects of the present disclosure. In addition, the data for subscriber of SIM2 is also sent/received using SIM2 in that interval but in non-overlapping durations (sub-frames). In other words, the data corresponding to SIMl and SIM2 is multiplexed into non-overlapping sub- frames. Such multiplexing can be performed even if each SIM has a corresponding transceiver.

[092] 6. Conclusion

[093] 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 of the present invention. 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. The following examples pertain to above or further embodiments.

[094] Thus, example 1 may correspond to a wireless device which generates a first packet for a first subscriber, and transmits the formed packet using a second SIM.

[095] In example 2, a wireless device checks whether a condition is satisfied requiring the first packet to be transmitted on a second SIM of the wireless device. If the condition is not satisfied, the wireless device transmits the first packet on a wireless medium using the first SIM. If the condition is satisfied, the wireless device transmits the generated packet using the second SIM.

[096] In example 3, the wireless device of any of examples 1-2, wherein the condition corresponds to a determination as to whether transmission of the first packet on the first SIM at a first requested power level, along with the power level at which packets are being transmitted on the second SIM, would exceed a threshold power level.

[097] In example 4, the condition corresponds to a determination that transmission of the first packet is mandated to be transmitted in a frequency band which is not supported by the device. [098] Example 5 may correspond to a wireless device which receives a second packet destined to a second SIM on the wireless medium according to a cellular network standard, and forwards the second packet to the first subscriber specified by a first SIM.

[099] In example 6, a wireless device in accordance with any of examples 1-5 indicates to a base station that the first SIM is operative as a remote user equipment (remoteUE) and the second SIM is operative as a relay user equipment (relayUE) of a sidelink communication, wherein the indication is provided prior to the transmitting of the first and second packets on the wireless medium.

[0100] In example 7, the subject matter of any of examples 1-6, wherein the first packet comprises a first Internet Protocol (IP) packet and the second packet comprises a second IP packet, wherein source IP address field of the first IP packet is set to an IP address of the first SIM, wherein destination IP address field of the second IP packet is set to the IP address of the first SIM, wherein the second packet is forwarded to the first subscriber in view of the destination IP address field of the second packet being set to the IP address allocated to the first SIM.

[0101] In example 8, the subject matter of any of examples 1-7, wherein the second packet contains a cyclic redundancy check (CRC) field comprising a value obtained based on the C- NTRI (Cell Radio Network Temporary Identifier) of the second SIM to be destined to the second SIM on the wireless medium according to the cellular network standard, wherein the wireless device processes the CRC field to determine that the second packet is to be processed by the second SIM.

[0102] In example 9, the subject matter of any of examples 1-8, wherein both of the first subscriber and the second subscriber are served by a same base station according to the cellular network standard.

[0103] In example 10, the subject matter of any of examples 1-9, wherein the cellular network standard comprises Long Term Evolution (LTE), wherein each of the first packet and the second packet is transmitted on the wireless medium in a corresponding LTE sub-frame.

[0104] The features of the above examples are also shown as implemented as respective apparatus/structures, methods, and also as a computer readable medium storing instructions which upon execution causes the above noted features to be operative.

[0105] 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.