PRIORITY APPLICATION

[001] This application claims the benefit of priority to India Application No. 201641042648, 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 devices, and more specifically to camping in the context of device-to-device communication capability in a wireless device.

[004] Related Art

[005] Wireless devices refer to devices such as mobile phones, tablets, etc., which are operable as user equipment (UE) according to cellular wireless standards. In a common scenario, a wireless device interfaces directly with a base station to communicate with other devices. The communication range of such a base station is said to define the boundaries of a cell, and the wireless device is physically located within the cell to communicate with the base station.

[006] Wireless devices are often provided the capability to communicate directly with other wireless devices, without the base station operating as a switching device. Such communication is referred to as device-to-device communication. LTE-D2D standard of 3GPP Release 12 or later, is one standard that specifies the requirements for such device to device communication.

[007] A wireless device needs to be camped on a cell for communicating to other devices (in the same or different cells) according to the cellular wireless standards. Camping refers to associating with a base station, which thereafter operates as a switching device for communications to and from the wireless device. In addition, the base station coordinates the transmission durations of all associated wireless devices by allocating shared wireless resources (e.g., frequency band and time slot).

[008] Aspects of the present disclosure are directed to camping in the context of device-to-device communication capability in a wireless device.

Brief Description of the views of Drawings

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

[010] Figure 1 is a block diagram of an exemplary environment in which several aspects of the present disclosure can be implemented. [Oil] Figure 2 is a flowchart illustrating the manner in which camping is performed in the context of device-to-device communication capability in a wireless device, according to aspects of the present disclosure

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

[013] Figure 4 is a diagram illustrating an exemplary multi-SIM scenario in which one of the SIMs is camped on a suitable cell when another SIM is configured for D2D communication.

[014] Figure 5 is a diagram illustrating an exemplary multi-SIM scenario in which one of the SIMs is camped on an acceptable cell when another SIM is configured for D2D communication.

[015] Figure 6 is an exemplary block diagram illustrating a scenario in which an out-of-coverage SIMs is camped on an acceptable cell when the SIM is also configured for D2D communication.

[016] 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

[017] 1. Overview

[018] A wireless device identifies multiple base stations within its communication range. The wireless device determines a first base station of the multiple base stations that is allocating resources for device-to-device (D2D) communication between the wireless device and another wireless device. The wireless device camps on a first cell defined by the first base station.

[019] 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.

[020] 2. Example Environment

[021] Figure 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 contain more systems/devices. Figure 1 shows base station (BS) 130, 140 and 150, and wireless devices (WD) 120 and 160.

[022] Each of BS 130, BS 140 and BS 150 is a fixed communications unit of a corresponding 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 the corresponding BS, and that have subscribed to services from the corresponding cellular network operator. BS 130 is shown as deployed by one cellular network operator PLMN-A (Public Land Mobile Network A). Each of BS 140 and BS 150 is shown as deployed by another cellular network operator PLMN-B (Public Land Mobile Network B).

[023] Although not shown in Figure 1, each of BS 130, BS 140 and BS 150 may be coupled to other devices/systems in the corresponding cellular network infrastructure to enable wireless devices in their coverage range to communicate with devices, with landline communications equipment in a conventional PSTN (Public Switched Telephone Network), public data networks such as the Internet, etc.

[024] The base stations and the wireless devices of Figure 1 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] In the context of LTE (Long Term Evolution), a BS 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, the base stations of Figure 1 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.

[026] Wireless devices 120 and 160 represent devices such as mobile phones, tablets, etc., and may be used for wireless communication such as voice calls, data services such as web browsing, receiving and sending emails, etc. In a common scenario, a wireless device located within the boundaries of a geographical area termed a 'cell' served by a base station of a mobile network, interfaces with the base station, which provides the corresponding user the facility of voice and data based services. The wireless device is said to 'be camped' on the cell covered by the base station. 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 network operator.

[027] With respect to Figure 1, wireless device 160 is assumed to be camped on the cell covered by BS 150. Although, wireless device 160 is assumed herein to be a single-SIM device, wireless device 160 can also be a multi-SIM device. For example, if wireless device 160 is a dual-SIM device, one SIM is camped on the cell corresponding to BS 150, while the other SIM can be camped on a cell corresponding to another base station, not shown.

[028] BS 150 supports device-to-device (D2) mode of operation between wireless device 160 and another wireless device (e.g., wireless device 120) as specified in section 5.10 (Sidelink) of Release 13 of 3GPP (3rd Generation Partnership Project) technical specification document TS 36.331 V13.1.0 (2016-03) . In D2D mode, a pair of wireless devices can communicate with each other (such communication path termed a sidelink) without the switching action of a base station for delivering individual information packets. However, the resources (e.g., frequency bands, time slots) that are required for the D2D communication need to be obtained from the corresponding base station before the D2D communication can start. BS 150 is therefore capable of allocating resources for D2D communication between wireless device 160 and another wireless device such as wireless device 120.

[029] Wireless device 120 may be a single-SIM or a multi-SIM device, and needs to select corresponding cell(s) to camp the SIM(s) on for accessing network services. Wireless device 120 also needs to access D2D communication service for direct communication with wireless device 160. The manner in which wireless device 120 selects a cell to camp for one or more SIMs in wireless device 120, when D2D communication is desired for a SIM in wireless device 120, is described next with respect to a flowchart.

[030] 3. Camping Approach

[031] Figure 2 is a flowchart illustrating the manner in which camping is performed in the context of device-to-device communication capability in a wireless device, according to aspects of the present disclosure. The flowchart is described with respect to wireless device 120 of Figure 1, 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.

[032] In step 210, wireless device 120 identifies cells that cover the location of wireless device 120. Thus, wireless device 120 may search for carrier signal power in various frequency bands allocated for wireless communication by the corresponding standard (e.g., LTE). The presence of carrier signal power from a base station above a threshold indicates that the coverage area of the cell corresponding to the base station covers the location of the wireless device. Thus, wireless device 120 identifies the presence of BS 130, BS 140 and BS 150 within its communication range. In addition to identification of presence of the base stations (of the covering cells), wireless device 120 may also identify (from signals received from the base stations) the corresponding cellular network operator (e.g., whether PLMN-A, PLMN-B etc.) of the base station. Control then passes to step 230.

[033] In step 230, wireless device 120 checks if any of the base stations (identified in step 210) has the current role of allocating resources for D2D communication between wireless device 120 and another wireless device. Thus, wireless device 120 checks whether there is a D2D communication session established with another wireless device, and the specific base station allocating the resources (i.e., time slot and frequency band) for the D2D communication. In one example embodiment described below, wireless device 120 maintains internal state information indicating the current active D2D sessions for any SIM, and the specific base stations which are allocating the resources for such D2D sessions. The state information is examined to determine the specific base station which has the current role of allocating resources for D2Dcommunication in step 230. If wireless device 120 finds such a base station, control passes to step 240. If wireless device 120 does not find any such base station, control passes to step 260.

[034] In step 240, wireless device 120 camps (a SIM) on the cell corresponding to the base station identified in step 230. Control then passes to step 299, in which the flowchart ends.

[035] In step 260, wireless device 120 camps (a SIM) on any one of the identified cells. Which of the identified cells wireless device 120 picks for camping may be based on other considerations such as, for example, signal strength of the corresponding base station as received at wireless device 120, whether the base station is deployed by the operator that the SIM is configured for, etc. Control then passes to step 299, in which the flowchart ends.

[036] By camping on a cell currently allocating resources for D2D communications (if such a cell is available and identified), wireless device 120 can obtain several benefits as illustrated below with respect to example scenarios. However, a description of the implementation details of wireless device 120 according to an aspect of the present disclosure is provided next.

[037] 4. Wireless Device

[038] Figure 3 is a block diagram representing an example wireless device in which several aspects of the present disclosure can be implemented. Wireless device 120 is shown containing processing circuitry or block 310, non-volatile memory 320, input/output (I/O) block 330, random access memory (RAM) 340, real-time clock (RTC) 350, SIM1 module 360 A, SIM2 module 360B, transmit (Tx) block 370, receive (Rx) block 380, switch 390, and antenna 395. Some or all units of wireless device 120 may be powered by a battery (not shown). In another aspect of the present disclosure, wireless device 120 is mains-powered and comprises corresponding components such as regulators, filters, etc. The specific blocks of wireless device 120 are shown by way of illustration only, and wireless device 120 may contain more or fewer blocks depending on specific requirements. SIMl and SIM2 share a same receiver (Rx Block 380) and a same transmitter (Tx Block 370). However, wireless device 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. 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.

[039] Each of SIMl 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 (SIM), such as SIMl or SIM2, can be inserted) and electrical/electronic circuits which together retrieve various data parameters stored on the inserted SIM cards. 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. 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 an alternative embodiment, '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.

[040] 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. SIMl 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.).

[041] 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 wireless device 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.

[042] 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.

[043] 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).

[044] 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.

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

[046] RAM 340 is a volatile random access memory, and may be used for storing instructions and data. RAM 340 may store state information indicating the presently active D2D communications provided for SIMs of wireless device 120. In the illustrative example(s) described in other sections, the state information would indicate that SIMl is currently engaged in D2D communication with wireless device 160 and that base station 580 is allocating the requisite resources on the shared wireless medium for such D2D communication. The state information can be stored in other memories (e.g., in registers) in alternative embodiments. As noted above in step 230, the state information thus maintained is examined to identify any base stations currently allocating resources for D2D communications between wireless device 120 and another wireless device.

[047] RAM 340 and non-volatile memory 320 (which may be implemented in the form of readonly 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 applications executing for SIM1 and SIM2.

[048] Processing block 310 (or processor 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 a SIM (e.g., SIM1 or SIM2) is noted as performing actions, such reference is to the corresponding processing core or execution thread performing such actions in relation to the corresponding SIM. In general, processing block 310 executes instructions stored in non-volatile memory 350 or RAM 340 to enable wireless device 120 to operate according to several aspects of the present disclosure, described in detail herein.

[049] The description is continued with illustrations of example scenarios of a wireless device selecting (or reselecting) a cell in the context of device-to-device communication capability in the wireless device.

[050] 5. Multi-SIM Scenarios

[051] Figure 4 illustrates a scenario in which SIM1 (of module 360A) of WD 120 is configured for D2D communication, and SIM2 (360B) is in the RRC (Radio Resource Control) Idle State. RRC idle state implies that SIM2 has not established a connection with a base station deployed by the network operator that SIM2 is configured for. In LTE technology, a cell corresponding to a base station deployed by network operator that a SIM is configured to subscribe to for services such as voice and data, is termed a suitable cell. WD 120 thus needs to select a cell to camp SIM2 on. The network operator for which SIM2 is configured is assumed to be PLMN-B.

[052] WD 120 is assumed to have camped SIM1 on a suitable cell (BS 130) deployed by the network operator (PLMN-A) that SIM1 is configured for, and the corresponding connection is shown by arrow 410. The set of uplink and downlink frequency bands for connection 410 is represented by Fl.

[053] WD 160 may be a single-SIM or multi-SIM device, and is assumed to have camped a SIM on a suitable cell (BS 150) deployed by the network operator (PLMN-B) that the SIM is configured for, and the corresponding connection is shown by arrow 460. The set of uplink and downlink frequency bands for connection 460 is represented by F3.

[054] Additionally, SIM1 of WD 120 is configured for D2D communication with another wireless device, assumed herein to be WD 160. Prior to D2D communication with WD 160, WD 120 would have discovered the presence of WD 160, and obtained the necessary resources for D2D communication with WD 160. The obtaining of the resources for D2D communication may be periodically performed, and may thus be a continuing process. The discovery is enabled by BS 130, which transmits SIBs (System Information Blocks) that contain relevant information that enable SIM1 to access a cell, perform cell re-selection, D2D communication, etc.

[055] In particular SIB 19 (according to LTE) contains a list of frequencies (along with PLMN IDs, such as PLMN-B, PLMN-C, etc.) on which WD 120 may monitor for the presence of another wireless device with which D2D communication can be performed. Thus, based on the information in SIB 19 transmitted by BS 130, WD 120 discovers WD 160 and requests BS 150 for resources to enable D2D communication with WD 160. The resources include frequency band for two-way communication with WD 160, and both transmit and receive are performed on the same band as the uplink band in F3. The D2D communication between SIM1 and WD 160 is indicated by arrow 450.

[056] With respect to camping SIM2 of WD 120 on a cell, WD 120 can choose either of BS 140 or BS 150 (both of operator PLMN-B), each of which is assumed to be within communication range of WD 120 (step 210 of the flowchart of Figure 2). The set of uplink and downlink frequency bands employed by BS 140 is denoted as F2.

[057] According to an aspect of the present disclosure, WD 120 camps SIM2 on BS 150 (step 230 and 240), rather than BS140, even if BS 140 provides a stronger carrier signal than BS 150), and the connection is indicated as 430 in Figure 4. WD 120 (in the form of processing block 310) stores information regarding the camping status of SIM1 as well as the status of D2D communication of SIM1 in RAM 340 or non-volatile memory 320. Therefore, when processing block 310 needs to make a decision on which of multiple available suitable cells for SIM2 to camp on, processing block 310 inspects the stored status for SIM1, and decides based on the stored status information.

[058] The camping approach for SIM2 as noted above may provide several benefits. Firstly, WD 120 needs to receive and decode SIBs from BS 150 alone for both camping of SIM2 on the cell corresponding to BS 150 (including subsequent operations to communicate with other devices or, in general, access services) as well as for obtaining resources for D2D communication of SIMl with WD 160. Had WD 120 camped SIM2 on BS 140 instead, WD 120 would have needed to receive and process SIBs from both BS 140 (for SIM2) and BS 150 (for D2D communication using SIMl), which would have been wasteful of power.

[059] Secondly, WD 120 needs to multiplex a shared receiver and transmitter only between Fl and F2, rather than Fl, F2 and F3. Therefore there are fewer number of times that a shared transmitter and receiver are switched between frequencies, thereby potentially improving throughput for the corresponding operations.

[060] While the description above with respect to Figure 4 has been provided with respect to selection of a cell for SIM2, according to an aspect of the present disclosure, a similar approach is used when a cell has to be reselected for SIM2. In the absence of BS 150 and absence of D2D communication by SIMl, WD 120 camps SIM2 on the cell corresponding to BS 140, or any other suitable cell if present (step 260 of the flowchart of Figure 2). Assuming multiple other suitable cells are present (in addition to cell corresponding to BS 140), WD 120 may camp SIM2 on that suitable cell that has the strongest signal (as received at WD 120).

[061] Another multi-SIM scenario in which aspects of the present disclosure operate is illustrated next with respect to Figure 5. The details of Figure 5 are identical to those of Figure 4 except for the following differences. BS 570 and BS 580 are shown in place of BS 140 and BS 150 respectively of Figure 4. The set of uplink and downlink frequency bands employed by BS 570 and BS 580 are respectively denoted by F4 and F5. F4 and F5 are different from F2 and F3 of Figure 4. BS 570 and BS 580 are deployed by a network operator (PLMN-C) for which SIM2 of WD 120 is not configured for. WD 120 camps SIMl on the cell corresponding to BS 130. SIMl is in D2D communication with WD 160, which is camped on BS 580. Arrow 550 represents D2D communication path between SIMl of WD 120 and WD 160. Arrow 560 represents the communication path between WD 160 and BS 580. Arrow 540 represents the communication path between SIMl of WD 120 and BS 580 for obtaining resources for D2D communication with WD 160.

[062] Figure 5 represents a scenario in which WD 120 is unable to find a suitable cell to camp SIM2 on (termed as an out-of-coverage situation), and therefore wishes to camp SIM2 on an acceptable cell to access limited services (e.g., emergency calls, disaster alerts, etc.). In LTE technology, a cell corresponding to a base station that is not deployed by the network operator that a SIM is configured to subscribe to for services, but which can provide limited services, is termed an acceptable cell. Each of BS 570 and BS 580 are assumed to be within communication range of WD 120, and therefore WD 120 can camp SIM2 for access to limited services on either BS 570 or BS 580.

[063] However, according to an aspect of the present disclosure, WD 120 camps SIM2 on BS 580 for limited services, since SIM1 has already established a connection (540) with BS 580 for requesting resources for D2D communications with WD 160. Camping SIM2 on BS 570 via connection 520 would be wasteful in terms of power in WD 120. The approach illustrated with respect to Figure 5 provides the same benefits as noted above with respect to Figure 4.

[064] 6. Single-SIM Scenario

[065] Figure 6 is a diagram illustrating a camping approach when WD 120 needs to support only one SIM (assumed to be SIM1), although having the capability to support two SIMs. WD 120 is assumed to have camped SIM1 on the cell corresponding to BS 130, and also to be currently communicating with WD 160 using D2D communication. WD 120 is assumed to have obtained the resources necessary for the D2D communication from BS 580 via connection indicated by arrow 640. The connection between WD 120 and WD 160 is denoted by arrow 650 and uses the uplink frequency band of BS 580. The set of uplink and downlink frequencies of BS 580 are denoted by F5. WD 160 is camped on BS 580, and the connection is indicated by arrow 660.

[066] Assuming WD 120 moves out of coverage range of BS 130, or if the signals from BS 130 were to drop below a predetermined threshold such that reliable communication is not possible between SIM1 and BS 130, WD 120 may wish to camp SIM1 on an acceptable cell to access limited services. Assuming both BS 570 and BS 580 are within coverage range of WD 120, WD 120 camps SIM1 on BS 580 (even if BS 570 provides stronger signals). The resulting benefits are similar to those noted above with respect to Figure 5 and Figure 6.

[067] 7. Conclusion

[068] 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.

[069] Example 1 corresponds to a wireless device containing a processing block which identifies base stations in communication range with the wireless device. The processing block operates to camp the wireless device on a first cell of one (first base station) of the base stations which allocates resources for D2D communication between the wireless device and another wireless device.

[070] Example 2 corresponds to the wireless device of example 1 in which the processing block operates to camp the wireless device on the first cell even though there is higher signal power from another base station in view of the first base station allocating resources for the D2D communication.

[071] Example 3 correspond to any of the wireless devices of example 1 and 2, wherein the wireless device contains a first holder for housing a first subscriber identity module (SIM); and a second holder for housing a second SIM, wherein the D2D communication is provided between the first SIM and the another wireless device, and wherein the second SIM is camped on the first cell defined by the first base station.

[072] Example 4 corresponds to any of the wireless devices of examples 1-3, wherein the first SIM is camped on a second cell as a suitable cell prior to the processing block identifying the base stations, wherein the processing block is further configured to receive, from the second cell, using the first SIM, a first set of System Information Blocks (SIB) that specify that the first base station supports D2D communication using a first frequency band, wherein the wireless device communicates on the first frequency band with the first base station to obtain a second set of SIBs specifying resources for the first SIM to communicate with the another wireless device, wherein the second set of SIBs also specify resources for the second SIM to access services via the first base station.

[073] Example 5 corresponds to any of the wireless devices of examples 1-4, wherein the first cell is a suitable cell with respect to the second SIM.

[074] Example 6 corresponds to any of the wireless devices of examples 1-4, wherein the first cell is an acceptable cell with respect to the second SIM.

[075] Example 7 corresponds to any of the wireless devices of examples 1-2, wherein the wireless device contains only a single SIM, wherein the processing block is further configured to find that the single SIM is unable to communicate with a second base station defining a previously camped cell, wherein the single SIM is in D2D (Device-to-Device) communication with the another wireless device prior to the finding, wherein the processing block is further configured to camp the single SIM on the first cell in response to finding that the single SIM is unable to communicate with the second base station defining the previously camped cell.

[076] Example 8 corresponds to any of the wireless devices of examples 1-2 and 7, wherein previously camped cell is a suitable cell, and the first cell is an acceptable cell.

[077] 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. [078] 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.