Method and apparatus for power efficient idle operation in a dual SIM CDMA EVDO mobile station

Methods and apparatus for configuring and scheduling paging intervals for a mobile station (MS) having multiple subscriber identity modules (SIMs) to be aligned are provided. The MS having multiple SIMs may operate in a network via a particular radio access technology (RAT), such as Code Division Multiple Access (CDMA) EVDO (Evolution-Data Optimized). By having aligned paging intervals, the MS may wake up only once during the paging cycles for the various SIMs rather than waking up multiple times, thereby reducing power consumption of the MS during idle mode compared to a conventional MS with multiple SIMs.

BACKGROUND

Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to configuring and scheduling paging intervals for a mobile station (MS) having multiple subscriber identity modules (SIMs) to be aligned in an effort to reduce power consumption during an idle mode.

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. For example, one network may be a 3G (the third generation of mobile phone standards and technology) system, which may provide network service via any one of various 3G RATs including EVDO (Evolution-Data Optimized), 1×RTT (1 times Radio Transmission Technology, or simply 1×), W-CDMA (Wideband Code Division Multiple Access), UMTS-TDD (Universal Mobile Telecommunications System-Time Division Duplexing), HSPA (High Speed Packet Access), GPRS (General Packet Radio Service), and EDGE (Enhanced Data rates for Global Evolution). The 3G network is a wide area cellular telephone network that evolved to incorporate high-speed internet access and video telephony, in addition to voice calls. Furthermore, a 3G network may be more established and provide larger coverage areas than other network systems.

CDMA EVDO is a 3G telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. EVDO uses multiplexing techniques including code division multiple access (CDMA) and time division multiple access (TDMA) to increase both individual users' throughput and the overall system throughput. EVDO is standardized by 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and has been adopted by many mobile phone service providers around the globe.

EVDO was designed as an evolution of the CDMA2000 (IS-2000) standard to support high data rates and be deployed alongside a wireless carrier's voice services. An EVDO channel has a bandwidth of 1.25 MHz similar to IS-95A (IS-95) and IS-2000 (1×RTT). The channel structure, on the other hand, is very different. Furthermore, the back-end network is entirely packet-based, and thus, is not constrained by the restrictions typically present on a circuit-switched network.

There have been several revisions of the EVDO standard, starting with Revision 0 (Rev 0). This was later expanded upon with Revision A (Rev A) to support Quality of Service (QoS) (e.g., to improve latency) and higher rates on the forward link and reverse link. Later in 2006 Revision B (Rev B) was published that, among other features, includes the ability to bundle multiple carriers to achieve even higher rates and lower latencies (see TIA-856 Rev B).

EVDO provides access to mobile devices with forward link air interface speeds of up to about 2.4 Mbit/s with Rev 0 and up to about 3.1 Mbit/s with Rev A. The reverse link rate for Rev 0 can operate up to about 153 kbit/s, while Rev A can operate at up to about 1.8 Mbit/s. EVDO was designed to be operated as an IP (Internet Protocol)-based network and can therefore support any application which can operate on such a network and bit rate constraints.

SUMMARY

In an aspect of the disclosure, a method for communicating with a mobile station (MS) in a network via a radio access technology (RAT) is provided. The method generally includes configuring a first paging interval for a first subscriber identity and configuring a second paging interval for a second subscriber identity, such that the first and second paging intervals are aligned.

In an aspect of the disclosure, an apparatus for communicating in a network via a RAT is provided. The apparatus generally includes means for configuring a first paging interval for a first subscriber identity and means for configuring a second paging interval for a second subscriber identity, such that the first and second paging intervals are aligned.

In an aspect of the disclosure, an apparatus for communicating in a network via a RAT is provided. The apparatus generally includes at least one processor and a memory coupled to the at least one processor. The at least one processor is typically configured to configure a first paging interval for a first subscriber identity and to configure a second paging interval for a second subscriber identity, such that the first and second paging intervals are aligned;

In an aspect of the disclosure, a computer-program product for communicating with an MS in a network via a RAT is provided. The computer-program product generally includes a computer-readable medium having code for configuring a first paging interval for a first subscriber identity and configuring a second paging interval for a second subscriber identity, such that the first and second paging intervals are aligned.

DETAILED DESCRIPTION

An Example Wireless Communication System

The methods and apparatus of the present disclosure may be utilized in a broadband wireless communication system. The term “broadband wireless” refers to technology that provides wireless, voice, Internet, and/or data network access over a given area. The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. By way of example and without limitation, the aspects of the present disclosure illustrated inFIG. 1are presented mainly with reference to a CDMA EVDO system.

FIG. 1illustrates an example of a wireless communication system100. The wireless communication system100may be a broadband wireless communication system. The wireless communication system100may provide communication for a number of cells102, each of which is serviced by a base station (BS)104. A base station104may be a fixed station that communicates with mobile stations106. The base station104may alternatively be referred to as a Node B, a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), or some other suitable terminology.

FIG. 1depicts various mobile stations106dispersed throughout the system100. The mobile stations106may be fixed (i.e., stationary) or mobile. A mobile station (MS)106may alternatively be referred to by those skilled in the art as a user terminal, a remote station, a subscriber station, a station (STA), user equipment (UE), a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. Examples of a mobile station106include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, a wireless modem, a personal digital assistant (PDA), a satellite radio, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a handheld device, or any other similar functioning device.

A variety of algorithms and methods may be used for transmissions in the wireless communication system100between the base stations104and the mobile stations106. For example, signals may be sent and received between the base stations104and the mobile stations106in accordance with the CDMA EVDO techniques. In these case, the wireless communication system100may be referred to as a CDMA EVDO system.

A communication link that facilitates transmission from a base station104to a mobile station106may be referred to as a downlink108, and a communication link that facilitates transmission from a mobile station106to a base station104may be referred to as an uplink110. Alternatively, a downlink108may be referred to as a forward link or a forward channel, and an uplink110may be referred to as a reverse link or a reverse channel.

A cell102may be divided into multiple sectors112. A sector112is a physical coverage area within a cell102. Base stations104within a wireless communication system100may utilize antennas that concentrate the flow of power within a particular sector112of the cell102. Such antennas may be referred to as directional antennas.

FIG. 2is a block diagram of a BS104in communication with an MS106in a network200operating according to a particular radio access technology (RAT). In the downlink communication, a transmit processor220may receive data from a data source212and control signals from a controller/processor240. The transmit processor220provides various signal processing functions for the data and control signals, as well as reference signals (e.g., pilot signals). For example, the transmit processor220may provide cyclic redundancy check (CRC) codes for error detection, coding and interleaving to facilitate forward error correction (FEC), mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM), and the like), spreading with orthogonal variable spreading factors (OVSF), and multiplying with scrambling codes to produce a series of symbols. Channel estimates from a channel processor244may be used by a controller/processor240to determine the coding, modulation, spreading, and/or scrambling schemes for the transmit processor220. These channel estimates may be derived from a reference signal transmitted by the MS106. The symbols generated by the transmit processor220are provided to a transmit frame processor230to create a frame structure. The frames are then provided to a transmitter232, which provides various signal conditioning functions including amplifying, filtering, and modulating the frames onto a carrier for downlink transmission over the wireless medium through antennas234. The antennas234may be implemented with beam steering bidirectional adaptive antenna arrays or other similar beam technologies.

At the MS106, a receiver254receives the downlink transmission through an antenna252and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver254is provided to a receive frame processor260, which parses each frame, and may provides a portion to a channel processor294and the data, control, and reference signals to a receive processor270. The receive processor270then performs the inverse of the processing performed by the transmit processor220in the BS104. More specifically, the receive processor270descrambles and despreads the symbols, and then determines the most likely signal constellation points transmitted by the BS104based on the modulation scheme. These soft decisions may be based on channel estimates computed by the channel processor294. The soft decisions are then decoded and deinterleaved to recover the data, control, and reference signals. The CRC codes are then checked to determine whether the frames were successfully decoded. The data carried by the successfully decoded frames will then be provided to a data sink272, which represents applications running in the MS106and/or various user interfaces (e.g., display). Control signals carried by successfully decoded frames will be provided to a controller/processor290. When frames are unsuccessfully decoded by the receiver processor270, the controller/processor290may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.

In the uplink, data from a data source278and control signals from the controller/processor290are provided to a transmit processor280. The data source278may represent applications running in the MS106and various user interfaces (e.g., keyboard). Similar to the functionality described in connection with the downlink transmission by the BS104, the transmit processor280provides various signal processing functions including CRC codes, coding and interleaving to facilitate FEC, mapping to signal constellations, spreading with OVSFs, and scrambling to produce a series of symbols. Channel estimates, derived by the channel processor294from a reference signal transmitted by the BS104, may be used to select the appropriate coding, modulation, spreading, and/or scrambling schemes. The symbols produced by the transmit processor280will be provided to a transmit frame processor282to create a frame structure. The frames are then provided to a transmitter256, which provides various signal conditioning functions including amplification, filtering, and modulating the frames onto a carrier for uplink transmission over the wireless medium through the antenna252.

The uplink transmission is processed at the BS104in a manner similar to that described in connection with the receiver function at the MS106. A receiver235receives the uplink transmission through the antenna234and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver235is provided to a receive frame processor236, which parses each frame, and provides a portion to the channel processor244and the data, control, and reference signals to a receive processor238. The receive processor238performs the inverse of the processing performed by the transmit processor280in the MS106. The data and control signals carried by the successfully decoded frames may then be provided to a data sink239and the controller/processor, respectively. If some of the frames were unsuccessfully decoded by the receive processor, the controller/processor240may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.

The controller/processors240and290may be used to direct the operation at the BS104and the MS106, respectively. For example, the controller/processors240and290may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The computer-readable media of memories242and292may store data and software for the BS104and the MS106, respectively. A scheduler/processor246at the BS104may be used to allocate resources to the MSs and schedule downlink and/or uplink transmissions for the MSs.

An Example Method for Power Efficient Idle Operation in a Dual SIM CDMA EVDO Mobile Station

In CDMA EVDO, the MS106in a slotted idle state will listen to a certain Control Channel Cycle (CCC). Each CCC has 256 slots or 426.67 ms (each slot lasts for 5/3 ms).

In EVDO Rev 0, the idle state protocol may allow the MS106to wake up for one CCC per 5.12 seconds, where 12 CCCs are available per 5.12 seconds.FIG. 3illustrates an example CDMA EVDO Rev 0 wake up time schedule300. Each CCC302has an index starting from the beginning of the CDMA System Time. The MS shall wake up on a CCC with index C satisfying:
(C+R)mod 12=0
The above parameter R may be set by either of the following options: (1) performing a random generation algorithm specified in the CDMA standards or (2) using an MS-preferred value, called PreferredControlChannelCycle. The MS may choose the above option (1) or (2) by setting a PreferredControlChannelCycleEnabled parameter to ‘0’ or ‘1,’ respectively. If the MS106decides to set the PreferredControlChannelCycle, the MS may use Generic Configuration Protocol to set this value by transmitting an EVDO Configuration Request message.

In EVDO Rev A, however, the enhanced idle state protocol may allow the MS106to wake up for a few possible sleep periods between 4 slots (or SlotCycle0) and 196608 slots (or SlotCycle15). The table400illustrated inFIG. 4shows various CDMA EVDO Rev A sleep period values. To conserve battery power, however, aspects of the present disclosure may only consider sleep periods greater than one CCC (i.e., the Slot Cycle is 7 or above in the table400).

EVDO Rev A protocols also allow the MS106to sleep with multiple stages of sleep periods: Period1, Period2, and Period3, subsequently. However, the final sleep period (i.e., Period3) will represent the final sleep period, and thus, Period3is of interest according to aspects of the present disclosure.

EVDO Rev A specifies that the MS shall wake up at the slot:
[T+256*R] mod Period=Offset
where Offset is 0, 1, 2, or 3 slots. This is in fact equivalent to CCC index C satisfying:
(C+R)modP=0, whereP=Period3/256
The above parameter R in EVDO Rev A may be set similar to Rev 0, either by a random generation formula or the PreferredControlChannelCycle.

In China and other countries, it is popular to operate a mobile station106with dual subscriber identity modules (SIMs). With two (or more) SIMs, a user can make and receive mobile calls with different phone numbers.

An MS with multiple SIMs may perform the EVDO registration procedures for each SIM independently. The EVDO registration procedure may include a Universal Access Terminal ID (UATI) assignment, an EVDO session setup, and a Point-to-Point Protocol (PPP) session setup. After completing the registration to the EVDO network for the multiple SIMs, the MS may enter the idle state.

In general, the MS may monitor EVDO paging messages according to different paging intervals (i.e., in terms of CCCs) because the EVDO sessions for the multiple SIMs may be assigned with different parameter R values. Consequently, if the MS has dual SIMs, the MS may have to monitor for paging messages twice as long as an MS with only one SIM (i.e., a single phone number).

As an example,FIG. 5illustrates the paging cycle500for a first SIM (SIM1) and the paging cycle502for a second SIM (SIM2). InFIG. 5, the paging intervals504for SIM1are offset six CCCs302from the paging intervals506for SIM2. Since the MS may most likely wake up from the idle state during the paging intervals504,506to listen for any paging messages, the power consumption of a dual-SIM MS may be approximately double that of a single-SIM MS during the idle state.

Accordingly, what is needed are techniques and apparatus for reducing the power consumption during idle mode for an MS with multiple SIMs.

FIG. 6is a functional block diagram conceptually illustrating example blocks600executed to configure paging intervals for an MS having multiple subscriber identities such that the paging intervals for the multiple subscriber identities are aligned. Operations illustrated by the blocks600may be executed, for example, at the processor(s)270,280, and/or290of the MS106fromFIG. 2.

The operations may begin, at block602, by configuring a first paging interval for a first subscriber identity. At block604, a second paging interval for a second subscriber identify may be configured, such that the first and second paging intervals are aligned (e.g., completely aligned or, in other words, the same). The configurations of the first and second paging intervals may be performed by the MS106(e.g., by sending a Configuration Request as described below) or by the BS104(e.g., by scheduling the paging cycles with the first and second paging intervals for the particular MS based on the received Configuration Request, as described below). The MS may monitor for a paging message for the first and/or the second subscriber identity during the aligned first and second paging intervals at block606. At block608, the MS may enter an idle state outside the aligned first and second paging intervals. During the idle state, at least a portion of the MS may be powered down in an effort to conserve battery power. In order to listen for the paging message at606, the MS may wake up from the idle state, powering up at least some of the components of the MS that were powered down during the idle state.

Certain aspects of the present disclosure configure the first and second paging intervals to be aligned by controlling the parameter R value such that the CCC for monitoring the paging messages for the first and second subscriber identities is the same. Two different solutions are described below for setting the parameter R.

FIG. 7illustrates an example call flow700for configuring the paging intervals for a dual-SIM MS to be aligned according to one solution for setting the parameter R. The call flow700may occur between an EVDO BS702and the MS106. At704, the MS may perform a first EVDO registration in order to register SIM1. The first EVDO registration may involve using the random number SessionSeed in the (enhanced) idle state protocol. This random number generation may involve the MS106sending a Configuration Request at706to the EVDO BS702with PreferredControlChannelCycleEnabled set to 0, thereby disabling PreferredControlChannelCycle. At708, the EVDO BS may respond with a Configuration Response having the parameter R set by the random number SessionSeed. Note that SessionSeed may be generated by the MS in the UATI assignment protocol.

At710, the MS106may perform a second EVDO registration in order to register SIM2. For the second EVDO registration, the MS may use the preferred value of parameter R identical to the parameter R set by the random number SessionSeed from the EVDO registration for SIM1. In other words, the MS may send a Configuration Request at712with PreferredControlChannelCycleEnabled set to 1 (thereby enabling PreferredControlChannelCycle) and PreferredControlChannelCycle set to R. At714, the EVDO BS702may respond with a Configuration Response agreeing to the request.

FIG. 8illustrates an example call flow800for configuring the paging intervals for the dual-SIM MS to be aligned according to another solution for setting the parameter R. The call flow800may occur between the EVDO BS702and the MS106. At704, the MS may perform a first EVDO registration in order to register SIM1. For the first EVDO registration, the MS may use a preferred value of parameter R in the (enhanced) idle state protocol. Performing the first session configuration using this preferred value may involve the MS106sending a Configuration Request at802to the EVDO BS702with PreferredControlChannelCycleEnabled set to 1 (thereby enabling PreferredControlChannelCycle) and PreferredControlChannelCycle set to a selected value R, designated as x inFIG. 8. At804, the EVDO BS may respond with a Configuration Response agreeing to the request.

At710, the MS106may perform a second EVDO registration in order to register SIM2. For the second EVDO registration, the MS may use the preferred value of parameter R identical to the parameter R selected for the first EVDO registration. In other words, the MS may send a Configuration Request at806with PreferredControlChannelCycleEnabled set to 1 and PreferredControlChannelCycle set to x again. At808, the EVDO BS702may respond with a Configuration Response agreeing to the request.

By using the same parameter R for SIM2as was randomly generated (as inFIG. 7) or designated (as inFIG. 8) for SIM1, the paging intervals504,506for both SIM1and SIM2may be completely aligned as illustrated inFIG. 9. The EVDO BS702may send a paging message for either SIM1or SIM2during particular CCCs—having indices C satisfying the R-dependent equations above—where the paging intervals504,506for SIM1and SIM2are the same, and the dual-SIM MS may then wake up from an idle state to listen for a paging message during these particular CCCs. By having only a single paging monitoring interval during the paging cycles500,502for SIM1and SIM2, the power consumption of a dual-SIM MS may be approximately equal to that of a single-SIM MS during the idle state (and approximately half that of a conventional dual-SIM MS with non-aligned paging intervals).

In one configuration, the apparatus for wireless communication (such as an MS with multiple subscriber identities) includes means for configuring a first paging interval for a first subscriber identity and means for configuring a second paging interval for a second subscriber identity, such that the first and second paging intervals are aligned. For certain aspects, the apparatus further comprises means for monitoring for a paging message for either the first or the second subscriber identity during the aligned first and second paging intervals. For certain aspects, the apparatus further comprises means for entering an idle state outside the aligned first and second paging intervals, wherein the means for monitoring for the paging message is configured to wake up from the idle state. In one aspect, the aforementioned means may be the processor(s)270,280, and/or290configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a module or any apparatus configured to perform the functions recited by the aforementioned means.

Several aspects of a telecommunications system have been presented with reference to a CVDA EVDO system. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards. By way of example, various aspects may be extended to UMTS (Universal Mobile Telecommunications System) systems such as W-CDMA, High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+) and TD-CDMA. Various aspects may also be extended to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), TD-SCDMA, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Several processors have been described in connection with various apparatuses and methods. These processors may be implemented using electronic hardware, computer software, or any combination thereof. Whether such processors are implemented as hardware or software will depend upon the particular application and overall design constraints imposed on the system. By way of example, a processor, any portion of a processor, or any combination of processors presented in this disclosure may be implemented with a microprocessor, microcontroller, digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable processing components configured to perform the various functions described throughout this disclosure. The functionality of a processor, any portion of a processor, or any combination of processors presented in this disclosure may be implemented with software being executed by a microprocessor, microcontroller, DSP, or other suitable platform.

Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium. A computer-readable medium may include, by way of example, memory such as a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disc (CD), digital versatile disc (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, or a removable disk. Although memory is shown separate from the processors in the various aspects presented throughout this disclosure, the memory may be internal to the processors (e.g., cache or register).

Computer-readable media may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.