DESC:FORM 2
THE PATENTS ACT, 1970
[39 of 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10; Rule 13)

SLOTTED CELL SEARCH IN HYBRID DATA IN MULTI-SIM DEVICES

SAMSUNG R&D INSTITUTE INDIA – BANGALORE Pvt. Ltd.
# 2870, ORION Building, Bagmane Constellation Business Park,
Outer Ring Road, Doddanakundi Circle,
Marathahalli Post,
Bangalore -560037, Karnataka, India
Indian Company

The following Specification particularly describes the invention and the method it is being performed

RELATED APPLICATION

The present invention claims benefit of the Indian Provisional Application No. 5369/CHE/2014 titled “SLOTTED CELL SEARCH IN HYBRID DATA IN MULTI-SIM DEVICES” by Samsung R&D Institute India – Bangalore Private Limited, filed on 28th October 2014, which is herein incorporated in its entirety by reference for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to wireless communications systems. The present invention more particularly relates to Wireless Wide Area Network (WWAN) devices supporting standby receive mode for multiple subscriptions/subscriber identification modules (SIMs) with single Radio Frequency (RF) transceiver, for instance, Dual SIM and Triple SIM cellphones.

BACKGROUND OF THE INVENTION

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

A multi-SIM multi-standby device supporting hybrid data allows packet data operation on one subscription (say SIM 1) and, in parallel, idle mode operations like Page monitoring, System Information reading, Cell search, Measurements on other subscription (say SIM 2). Each occurrence of idle mode operation on other subscription results in temporary pause of data operation on the first subscription as RF transceiver is single and shared across all subscriptions. Typically, idle mode operations are short duration so the temporary drop in first subscription’s data throughput is not perceivable by user at the application level.

However, cell search operation can take multiple seconds or minutes causing disruption to the User data session. The conventional way of doing cell search operation is one-shot approach where all the required frequencies (across one or more bands) are scanned and searched in contiguous manner. The amount of time taken by this search depends on the number of frequencies scanned, RF conditions/pollution, type of search, etc. Given that today’s WWAN devices support multiple bands for each technology, the cell search time can easily run into minutes in dense RF conditions (multiple operators transmitting on multiple frequencies in different bands and for different technologies/RATs). The discontinuity in data session on first subscription due to this cell search duration is long enough to cause data disruption for user at application level and degrade user experience.

In view of the foregoing, there exists the need for an improved cell search scheme for hybrid data to avoid disruption of user data session.

The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

SUMMARY OF THE INVENTION

The various embodiments of the present invention disclose a Dual-Subscriber Identity Module (Dual-SIM) device and a method of optimizing slotted cell search by a Dual-SIM device. The method comprises of performing a packet-based activity on a first SIM of the dual-SIM device for a first timeslot provided by a first timer, performing a cell-search activity on a second SIM of the dual-SIM device for a second timeslot provided by the second timer and alternately performing the packet-based activity for the first timeslot and the cell-search activity for the second timeslot by switching between the first timer and the second timer.

According to an embodiment herein, a Radio Frequency resource is shared between the first SIM during the first time slot and the second SIM during the second time slot.

According to an embodiment herein, the duration of the first time slot and a duration of the second time slot are dynamically adjustable to control the cell search operation.

Embodiments herein further disclose a Dual-Subscriber Identity Module (Dual-SIM) device, comprising a first SI, a second SIM, a first timer, a second timer and a controller adapted for performing a packet-based activity on the first SIM for a first timeslot provided by the first timer, performing a cell-search activity on the second SIM for a second timeslot provided by the second timer; and switching between the first timer and the second timer to alternatively perform the packet-based activity for the first timeslot and the cell-search activity for the second timeslot.

The foregoing has outlined, in general, the various aspects of the invention and is to serve as an aid to better understanding the more complete detailed description which is to follow. In reference to such, there is to be a clear understanding that the present invention is not limited to the method or application of use described and illustrated herein. It is intended that any other advantages and objects of the present invention that become apparent or obvious from the detailed description or illustrations contained herein are within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS
The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

Figure 1 is a schematic flow diagram illustrating slotted cell search in a dual-SIM device, according to an embodiment of the present invention.

Figure 2 is a system diagram of a Dual-SIM device according to an embodiment of the present invention.

Figure 3 is a flow chart illustrating a method of optimizing cell search by a Dual-SIM device, according to an embodiment of the present invention.

Although specific features of the present invention are shown in some drawings and not in others, this is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention discloses a method of optimizing slotted cell search in hybrid data in devices supporting standby receive mode for multiple subscriptions with single RF transceiver, such as dual-SIM and Multi-SIM devices. In the following detailed description of the embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

According to an embodiment herein, the slotted cell search is implemented using two timers in Radio Resource Control (RRC) which is Layer 3 in wireless protocol stack and also known by other names as Radio Resource (RR), Radio Resource Management (RRM), etc. The first timer is initiated for a first time slot, TsearchOn and the second timer is activated for a second time slot, Tsearch off. The radio frequency is shared between the packet data on first SIM for the first time slot and cell search on the second SIM for the second time slot. The RRC layer runs the first timer

RF is shared between Packet Data on first subscription (for TsearchOff duration) and cell search on other subscription (for TsearchOn duration). The Radio Resource layer runs these 2 timers in alternate fashion, i.e. TsearchOn followed by TsearchOff followed by TsearchOn, and so on. Association of these timers to a specific layer in stack is implementation dependent and can be different in different implementations

Figure 1 is a schematic flow diagram illustrating slotted cell search in hybrid data in dual-SIM device, according to the present invention. The embodiments of the present invention, the slotted cell search scheme is described in view of the first SIM 102 being in the packet data reception mode and the second SIM 104 needing the Radio Frequency layer temporarily for the idle mode operation. This means that the cell search happens for the second SIM when data activity happens in the first SIM.

The cell search operation herein is divided into periodic fixed duration search slots. The first SIM 102 uses the RF resource, which is the RF transceiver, the time between consecutive search slots of the second SIM 104 for reception of data packets. This approach ensures that RF transceiver is not taken away from the first SIM 102, for a long time, thereby ensuring hybrid data throughput and good user data experience.

According to Figure.1, the slotted cell search is implemented using a first Timer , TsearchOn and a second Timer TsearchOff, in the Radio Resource Control (RRC) layer. The RRC layer is the Layer 3 in wireless protocol stack and also known by other names as Radio Resource (RR), Radio Resource Management (RRM), etc. The RF transceiver is shared between Packet Data on first SIM 102 for a first time slot (for TsearchOff duration) and cell search on the second SIM 104104 for a second time slot (for TsearchOn duration). The RRC multi-SIM controller106 alternates the first time slot and the second time slot to control the cell search operation.

The slotted cell search is similarly applicable, when the second SIM 104 is in the packet data reception mode and the first SIM 102 needs the RF transceiver temporarily for the idle mode operation.

Figure 2 is a block diagram of a Dual-SIM device 200, according to an embodiment of the present invention. The Dual-SIM device 200 herein comprises a first SIM, SIM1 102, a second SIM, SIM 2 104, a SIM switch 202, a dual-SIM controller 106, a first timer, Timer 1 206a, a second timer, Timer 2 106b, memory 208, a wireless communication unit 210, an RF transceiver 212, a user interface 214 and a display unit 216. However, the constituent elements as illustrated in FIG. 2 are not necessarily required, and the dual-SIM device 200 may be implemented with greater or less number of elements than those illustrated elements.

According to Figure.1, the slotted cell search is implemented using the Timer 1 206a and the Timer 2 206b. , in the Radio Resource Control (RRC) layer. The RRC layer is the Layer 3 in wireless protocol stack and also known by other names as Radio Resource (RR), Radio Resource Management (RRM), etc. The RF transceiver 212 is shared between Packet Data on the first SIM 102 for a first time slot (for TsearchOff duration) and cell search on the second SIM 104 for a second time slot (for TsearchOn duration). The RRC multi-SIM controller106 alternates the first time slot and the second time slot to control the cell search operation.

The first SIM 102 and the second SIM 104 are selectively connected to the controller 106 through a SIM switch 202. The controller 106 controls to perform SIM switching between the two SIMS 102 and 104 when the two SIMS 102 and 104 provide different services, thereby providing the user's desired service through the RF transceiver 212.

The wireless communication unit 210 typically includes one or more modules allowing radio communication between the dual-SIM device 200 and a wireless communication system, or allowing radio communication between radio communication the dual-SIM device 200 and a network in which the dual-SIM device 200 is located.

The user interface 214 performs a role of interfacing with all external devices connected to the dual-SIM device 200. The user interface 214 may include, for example, wired/wireless headset ports, external charger ports, wired/wireless data ports, memory card ports, ports for coupling devices having an identification module, audio Input/Output (I/O) ports, video I/O ports, earphone ports, and the like.

The display unit 216 may display (output) information processed in the dual SIM device 200. For example, when the dual-SIM device 200 is in a phone call mode, the display unit 216 may display a User Interface (UI) or a Graphic User Interface (GUI) associated with a call

Figure 3 is a flow chart illustrating a method of performing slotted cell search by a Dual-SIM device, according to an embodiment of the present invention. At step 302, the dual SIM device performs a packet-based activity on the first SIM for a first timeslot provided by the first timer. At step 304, the Dual-SIM device performs a cell-search activity on the second SIM for a second timeslot provided by the second timer. At step 306, the dual SIM device alternatively performs the packet-based activity for the first timeslot and the cell-search activity for the second timeslot by switching between the first timer and the second timer.

Although only RF transceiver has been discussed as a resource for cell search in the above descriptions, it is to be understood that the Slotted Cell Search scheme is applicable in the same way for any common resource that may be needed by both SIMS, for e.g, TCXO oscillator which is typically a single clock source in such wireless devices.

According to an embodiment herein, the slotted cell search herein is not limited to dual SIM devices and can be extended to any multi-SIM device.

The slotted cell search in hybrid data provides for better user experience of hybrid data in a dual SIM device as the impact on data throughput by the cell search operation on the second SIM is minimal. Further, this approach provides tune-able performance of hybrid data scenario as the timers TsearchOn and TsearchOff are adjusted for better data throughput or faster cell search. This implies that the second time slot for which the RRC scans frequencies on the second SIM for cell search is increased or decreased to minimize interruptions on the data search activity of the first SIM and vice versa. The slotted cell search scheme as disclosed herein is simple, robust and optical scheme which is applicable to all radio access technologies such as 2G, 3G, 4G and so on.

Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.

,CLAIMS:
CLAIMS

We Claim:

1. A method of optimizing cell search by a Dual-Subscriber Identity Module (Dual-SIM) device, comprising:
performing a packet-based activity on a first SIM of the dual-SIM device for a first timeslot provided by a first timer;
performing a cell-search activity on a second SIM of the dual-SIM device for a second timeslot provided by the second timer; and
alternately performing the packet-based activity for the first timeslot and the cell-search activity for the second timeslot by switching between the first timer and the second timer.

2. The method of claim 1, wherein a Radio Frequency resource is shared between the first SIM during the first time slot and the second SIM during the second time slot.

3. The method of claim 1, wherein a duration of the first time slot and a duration of the second time slot are dynamically adjustable to control the cell search operation.

4. A Dual-Subscriber Identity Module (Dual-SIM) device, comprising:
a first SIM;
a second SIM;
a first timer;
a second timer; and
a controller adapted for:
performing a packet-based activity on the first SIM for a first timeslot provided by the first timer;
performing a cell-search activity on the second SIM for a second timeslot provided by the second timer; and
switching between the first timer and the second timer to alternatively perform the packet-based activity for the first timeslot and the cell-search activity for the second timeslot.

5. The Dual SIM device of claim 1, wherein the controller shares a Radio Frequency resource between the first SIM during the first time slot and the second SIM during the second time slot.

Dated this the 14th day of September 2015
Signature

KEERTHI J S
Patent agent
Agent for the applicant