Abstract:
A method for activating a remote device is provided. In response to a determination that a remote device is within a first mode signal range of a vehicle and the remote device is moving, the method activates a second mode communication module of the remote device.

Description:
TECHNICAL FIELD 
       [0001]    The subject matter presented herein generally relates to vehicles, and more particularly relates to passive-entry, passive-start (PEPS) systems and conserving the battery life of a remote device connected to a PEPS system. 
       BACKGROUND 
       [0002]    A passive-entry, passive-start system allows a driver, or anyone who possesses an authorized remote device, such as a key fob, to unlock a vehicle&#39;s doors as they approach the vehicle without touching a remote device. Once the remote device is within range of the vehicle, locked doors can be opened by pulling a door handle. In addition, some passive-entry, passive-start (PEPS) systems can be configured to automatically start the vehicle&#39;s engine as an authorized remote device approaches the vehicle. Other PEPS systems require that the driver pushes an ignition button to start and/or stop the vehicle engine. 
         [0003]    A problem with current PEPS functionality is that an authorized remote device must constantly be powered on or, in other words, connected to an active power supply, which may quickly utilize all available power (i.e., drain the battery of the remote device). The hardware is continuously active so that it can detect whether or not a vehicle is in range and the automatic functionality may be activated when appropriate. However, during certain periods of time when the remote device is not active, it is not necessary for the hardware to remain powered on. For example, when a remote device (such as a key fob) is outside of a pre-defined range of use, it will not be performing actions associated with PEPS functionality. In this example, the remote device will not be used, and will therefore not require power. Accordingly, it is desirable to conserve power within a remote device, in ways that will still allow the automatic functionality of the PEPS system to remain operational during times that it is possible to use it. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. 
       SUMMARY 
       [0004]    Some embodiments provide a method for conserving power in a remote device. The method receives, at the remote device, a first signal emitted by a vehicle; evaluates motion data from the remote device to determine a movement status of the remote device, wherein the evaluating is performed in response to receiving the first signal; and transitions a first wireless communication module of the remote device from a low power mode to an active mode, when the motion data indicates that the remote device is moving. 
         [0005]    Some embodiments provide a method for activating a remote device. In response to a determination that a remote device is within a first mode signal range of a vehicle and the remote device is moving, the method activates a second mode communication module of the remote device. 
         [0006]    Some embodiments provide a system comprising a remote device and a vehicle module, which are configured to communicated with one another using a first mode and a second mode, and which are further configured to perform a method. The method detects, at the remote device, presence of the vehicle module within a first mode signal range; polls an internal accelerometer of the remote device to obtain internal accelerometer data; analyzes the obtained internal accelerometer data to determine whether the remote device is in motion; and activates a second mode communication module within the remote device when the analyzing determines that the remote device is in motion. 
         [0007]    This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
         [0008]    DESCRIPTION OF THE DRAWINGS 
         [0009]    The exemplary embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
         [0010]      FIG. 1  is a functional block diagram of a PEPS system, in accordance with an embodiment; 
         [0011]      FIG. 2  is a flow chart that illustrates an embodiment of conserving power in a remote device, from the perspective of the remote device; and 
         [0012]      FIG. 3  is a flow chart that illustrates another embodiment of conserving power in a remote device, from the perspective of a system. 
     
    
     DETAILED DESCRIPTION 
       [0013]    The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
         [0014]    The subject matter presented herein relates to methods and apparatus used to optimize battery life in a remote device that is in communication with a PEPS system associated with a vehicle. In certain embodiments, the remote device utilizes a “sleep mode” (i.e., a low power mode) regularly, a condition in which the internal circuitry of the remote device is predominantly turned off. When the remote device determines that it is located within an authorized signal range of the vehicle and is approaching the vehicle, the internal circuitry of the remote device is activated. 
         [0015]    The vehicle may be, without limitation, any one of a number of different types of types of automobiles (cars, trucks, motorcycles, sport-utility vehicles, vans, etc.), aviation vehicles (such as airplanes, helicopters, etc.), watercraft (boats, ships, jet skis, etc.), trains, all-terrain vehicles (snowmobiles, four-wheelers, etc.), military vehicles (Humvees, tanks, trucks, etc.), rescue vehicles (fire engines, ladder trucks, police cars, emergency medical services trucks and ambulances, etc.), spacecraft, hovercraft, and the like. 
         [0016]    Referring now to the drawings,  FIG. 1  is a functional block diagram of a PEPS system  100 , in accordance with an exemplary embodiment. In accordance with some embodiments, the PEPS system  100  may include, without limitation: a remote device  102 , including a remote signal transceiver  104 , a movement sensor module  106 , and a remote wireless communication module  108 ; and a vehicle  110 , including a plurality of antennas  112 , a vehicle signal transceiver  114 , and a vehicle wireless communication module  116 . 
         [0017]    The remote device  102  may be any wireless communications device such as a smart phone or other cellular phone, a laptop or palmtop computer, a tablet computer, a PDA, a remote controller, a key fob, a watch, a gaming pad, an entertainment device or any other device enabled to utilize wireless communication to communicate with a vehicle  110 . 
         [0018]    Further, it is noted that the PEPS system  100  may support the use of multiple remote devices  102 , which may function independently of one another or cooperate with one another in a desired manner. For example, the PEPS system  100  may be defined to include multiple different devices in some implementations (e.g., a key fob and a wireless communication device such as a smart phone). As such, if a driver has a smart phone and a key fob (utilizing the same wireless communication standard signal type) with them, the system can process signal strength information from each of those devices independently to determine the proximity of the driver to the vehicle. This is also useful in situations where one of the devices is not available (e.g., is lost, out of power, does not work) since it provides a backup. For example, in one situation, the smart phone could be powered off or otherwise inactive, but the driver may have his key fob with him, or vice-versa. In another situation, the driver may have accidentally locked his key fob in the car and only has a smart phone with him. 
         [0019]    The remote signal transceiver  104  within the remote device  102  may include a radio frequency transmitter and receiver, and communicates with another remote signal transceiver, such as vehicle signal transceiver  114  of a vehicle  110 . In certain embodiments, the remote signal transceiver  104  continuously sends and receives low frequency signals, and requires minimal electric current to operate in a powered-on mode consistently. In the context of this application, a low frequency signal may fall within the range of 30 kilohertz (kHz) to 300 kHz, and a very low frequency signal may fall within the range of 3 kHz to 30 kHz. Also in the context of this application, low or minimal electric current may refer to values less than 20 microamps (μA). 
         [0020]    The movement sensor module  106  is able to detect whether or not the remote device  102  is in motion, and may include any device, system, feature, or technology for determining acceleration, orientation, location, etc. In certain embodiments, one or more accelerometers (e.g., piezoelectric-based accelerometers, MEMS-based accelerometers, etc.) gyroscopes, or other motion-based sensors may be used. In some embodiments, infrared (IR) and/or magnetic field technology may be used for purposes of determining a location, position, and/or orientation of the remote device  102 . 
         [0021]    The remote wireless communication module  108 , located within the remote device  102 , transmits and receives wireless communication signals with an associated vehicle wireless communication module  116 . In certain embodiments, the remote wireless communication module  108  is a Bluetooth-enabled device, including a Bluetooth antenna and a Bluetooth chipset (not shown). In this example, the remote wireless communication module  108  is capable of implementing all known Bluetooth standards and protocols including a Bluetooth Low Energy (BLE) protocol, as described in Bluetooth Core Specification Version 4.0, which includes Classic Bluetooth, Bluetooth High Speed (HS) protocols and Bluetooth Low Energy (BLE). 
         [0022]    The remote wireless communication module  108  differs from the remote signal transceiver  104  in frequency range of communication, communication protocols used, and power consumption. The remote wireless communication module  108  utilizes a much higher frequency range than the remote signal transceiver  104 . In certain embodiments, the remote wireless communication module  108  operates at approximately 2.4 GHz, while the remote signal transceiver  104  utilizes a low frequency signal range of 30 kHz-300 kHz. The remote wireless communication module  108  also consumes significantly more power than the remote signal transceiver  104 , and in order to save power (i.e., to preserve battery life) in the remote device  102 , the remote wireless communication module  108  remains in a sleep-state until required for use, while the remote signal transceiver  104  remains activated. 
         [0023]    The remote wireless communication module  108  has the ability to go into “sleep mode” (i.e., low power mode), in which its power supply is cut off and most if not all of the vehicle support functionality associated with the remote wireless communication module  108  is effectively turned off The “sleep mode” setting prevents the remote device  102  from utilizing unnecessary amounts of power. In this regard, the remote device  102  “wakes up” from the sleep mode (i.e., powers on) only when needed for use. Once powered on, the remote wireless communication module  108  advertises over one or more channels (i.e., transmits a signal for recognition by a vehicle wireless communication module  116 ) and is able to establish as communication connection with the vehicle wireless communication module  116  via a data channel. In some embodiments, the advertising channels and the data channel are compliant with Bluetooth Low Energy (BLE) communication standards and, therefore, the remote wireless communication module  108  can be involved. An established communication connection between a remote wireless communication module  108  and a vehicle wireless communication module  116  is established for performing at least one PEPS function (e.g., the doors are unlocked, engine is started, etc.) with respect to a vehicle as the remote device  102  approaches the vehicle  110  and meets authorization criteria. 
         [0024]    Referring now to the configuration of the vehicle  110 , the plurality of antennas  112  generally includes four or more antennas  112  located on the vehicle  110 , which have the ability to communicate with the remote wireless communication module  108  and the vehicle wireless communication module  116 . In certain embodiments, the vehicle  110  employs external antennas  112 , which may be located in the door handles, wheels, or other components of the vehicle  110 . Although these vehicle components may have another primary function on the vehicle  110 , they may also be used in the PEPS system  100  to support the features and functions described in more detail herein. In other embodiments, however, the plurality of antennas  112  may include standalone antennas, which are not incorporated into other vehicle components. 
         [0025]    As used in the PEPS system  100 , the plurality of antennas  112  detects and measures the signal strength of an emitted wireless signal from the remote wireless communication module  108 . In certain embodiments, the plurality of antennas  112  includes four or more Bluetooth antennas, which detect a signal strength of a remote wireless communication module  108  that is implemented as a Bluetooth Low Energy module. In this example, the plurality of antennas  112  also communicates with a vehicle wireless communication module  116  that is also implemented as a Bluetooth Low Energy module. The detected signal strength is then communicated to the vehicle wireless communication module  116  for further analysis. 
         [0026]    The vehicle signal transceiver  114  within the vehicle  110  is similar to the remote signal transceiver  104 , and may include a radio frequency transmitter and receiver for communication with another remote signal transceiver, such as remote signal transceiver  104 . In certain embodiments, the signal transceiver  104  continuously sends and receives low frequency signals, and requires minimal power to consistently operate in a powered-on mode. 
         [0027]    The vehicle wireless communication module  116 , located within the vehicle  110 , transmits and receives wireless communication signals with the associated remote wireless communication module  108 . In certain embodiments, the vehicle wireless communication module  116  is a Bluetooth-enabled device, including a Bluetooth antenna and a Bluetooth chipset (not shown). Similar to the remote wireless communication module  108  that is implemented as a Bluetooth-enabled device, the vehicle wireless communication module  116  is capable of implementing all known Bluetooth standards and protocols including a Bluetooth Low Energy (BLE) protocol, as described in Bluetooth Core Specification Version 4.0, which includes Classic Bluetooth, Bluetooth High Speed (HS) protocols and Bluetooth Low Energy (BLE). 
         [0028]    The vehicle wireless communication module  116  is also capable of maintaining a “sleep mode” status when not in use, and is configured to receive power when needed for use. Once the vehicle wireless communication module  116  is powered on, it performs a scan of advertising channels, seeking a connection with an appropriate remote wireless communication module  108  within a remote device  102 . This connection is sought for performing at least one PEPS function (e.g., the doors are unlocked, engine is started, etc.) with respect to a vehicle as the remote device  102  approaches the vehicle  110  and meets authorization criteria. 
         [0029]      FIG. 2  is a flow chart that illustrates an embodiment of conserving power in a remote device. The various tasks performed in connection with a process described here may be performed by software, hardware, firmware, or any combination thereof. For illustrative purposes, the description of a process may refer to elements mentioned above in connection with  FIG. 1 . In practice, portions of a described process may be performed by different elements of the described system, e.g., the remote device or any of its internal parts, including the signal transceiver, movement sensor, and/or wireless communication module; or the vehicle or any of its internal parts, including the plurality of antennas, signal transceiver, and/or the wireless communication module; or other components of the system. It should be appreciated that a described process may include any number of additional or alternative tasks, the tasks shown in the figures need not be performed in the illustrated order, and that a described process may be incorporated into a more comprehensive procedure or process having additional functionality not described in detail herein. Moreover, one or more of the tasks shown in the figures could be omitted from embodiments of a described process as long as the intended overall functionality remains intact. 
         [0030]    For ease of description and clarity, this example assumes that the process  200  begins with a remote device determining whether it is within signal range of a vehicle (step  202 ). The remote device begins in “sleep mode” (i.e., low power mode), and a signal receiver at the remote device is “listening” for a first mode signal continuously, in an attempt to detect the presence of the vehicle within signal range. The signal receiver at the remote device cannot receive a low frequency signal when it is out of signal range of the vehicle; thus, step  202  can only be performed when the remote device is within a specified distance of the vehicle. The remote device is in “listening” mode when operating in a low power mode and searching for a vehicle within first signal range. The remote device is in low power mode (i.e., “sleep mode”) when an internal wireless communication module has been deactivated for purposes of power conservation. When it is determined that the remote device is not within signal range of the vehicle (the “No” branch of  202 ), the remote device continues to operate in low power mode and to “listen” for the first mode signal. 
         [0031]    When it is determined that the remote device is within signal range of the vehicle (the “Yes” branch of  202 ), the signal receiver on the remote device receives a first mode signal emitted by a vehicle (step  204 ). In certain embodiments, the first mode signal may be a low frequency signal that is continuously broadcast by a transmitter onboard a vehicle. In other embodiments, the signal may be intermittently broadcast using designated time-intervals. Generally, detection of this signal indicates to the remote device that the vehicle is within a signal range in which PEPS functionality is operational. 
         [0032]    Next, the process  200  initiates an evaluation of motion data (step  206 ) at the remote device. The motion data indicates movement in which the remote device is engaged. In certain embodiments, the motion data is derived from accelerometer data, when the accelerometer is a feature of the remote device. In this example, the motion data includes a measurement of any force of acceleration, which can be caused by movement of the remote device. In some embodiments, the motion data is derived from gyroscope data, when the gyroscope is a feature of the remote device. In other embodiments, the motion data is derived from other motion sensors which are features of the remote device. 
         [0033]    Following the evaluation of motion data (step  206 ), the remote device uses the motion data to determine whether it is moving (step  208 ). When it has been determined that the remote device is not moving (the “No” branch of step  208 ), the remote device returns to the beginning of process  200 , by transitioning into “listening” mode and searching for a first signal emitted by a vehicle (step  202 ). 
         [0034]    When it has been determined that the remote device is moving (the “Yes” branch of step  208 ), the remote device activates an internal wireless communication module (step  210 ). Up to this point in the process  200 , the wireless communication module has been in a low power mode, or powered off, for the purposes of conserving battery power in the remote device. When the motion data indicates that the remote device is moving, it is assumed that the remote device is approaching the vehicle. The wireless communication module is powered on at this point, and is ready for use. 
         [0035]      FIG. 3  is a flow chart that illustrates another, more detailed, embodiment of conserving power in a remote device, from the perspective of the PEPS system  100 . This example illustrates the steps in the process  300  that are performed by a remote device process  302  and a vehicle process  324 , and how they relate to each other to complete the process  300 . 
         [0036]    The process  302  involves the remote device, which begins operation in a state of minimal power use. In  FIG. 3 , step  304  corresponds to the remote device searching or listening for a first mode signal, while simultaneously broadcasting a first mode signal for purposes of detection by a vehicle. The first mode signal may be implemented as any wireless communication requiring minimal power to broadcast. In some embodiments, the first mode signal may be a low frequency signal, which may be continuously emitted from both the vehicle and the remote device. In other embodiments, another signal broadcast scheme may be implemented, such as a signal that is broadcast on a time interval. Presence of the first mode signal is an indication to the remote device that the vehicle is located within a range for wireless communication, and may be available for connection. As indicated by the “No” branch of step  306 , the remote device remains in a searching or listening mode until a first mode signal is detected. 
         [0037]    After the remote device detects a first mode signal (the “Yes” branch of step  306 ), the remote device then evaluates motion data (step  308 ) to determine if the remote device is in motion (step  310 ). The motion data may include accelerometer data, gyroscope data, or other motion sensor data indicating that the remote device is moving. If the remote device is not in motion (the “No” branch of  310 ), the remote device returns to the beginning of process  302  to broadcast a first mode signal and to search for a first mode signal emitted by a vehicle (step  304 ). If the remote device is in motion (the “Yes” branch of  310 ), the remote device transitions from low power mode to active mode (step  312 ) or in other words, converts from “sleep mode” in which the wireless communication module is powered off to an active mode in which the wireless communication module is powered on. 
         [0038]    After the remote wireless communication module has transitioned to the active mode (step  312 ), the remote device advertises the presence of an internal wireless communication module (step  314 ) of the remote device. The signal advertising the presence of the remote device is a second mode signal, which may utilize any wireless communication standard, such as Bluetooth or Bluetooth Low Energy. The second mode signal is transmitted by a wireless communication module, which is separate and distinct from the first mode signal transceiver. 
         [0039]    While advertising the presence of the internal wireless communication module (step  314 ), the remote device may receive signal transmissions from the vehicle, such as a deactivation signal or a signal establishing a connection with the internal wireless communication module. If a deactivation signal is received from the vehicle (the “Yes” branch of  316 ), then the remote device transitions from active mode back to low power mode (step  318 ), and returns to the beginning of process  302  to search for a first mode signal emitted by a vehicle (step  304 ). However, if a deactivation signal from the vehicle is not received (the “No” branch of  316 ), the remote device may still receive signal transmissions. If a signal to establish a connection with the vehicle is not received (the “No” branch of  320 ), the remote device returns to advertising the presence of a remote wireless communication module via signal transmission over advertising channels (step  314 ). If a signal to establish a connection with the vehicle is received (the “Yes” branch of  320 ), the remote device accepts the connection for communication with the vehicle (step  322 ), or more specifically, the remote device accepts the connection for communication with a wireless communication module of the vehicle. 
         [0040]    The process  324  involves the vehicle, which broadcasts a first mode signal for detection by a remote device in low power mode, and listens for a first mode signal emitted by the remote device. In  FIG. 3 , step  326  corresponds to the vehicle broadcasting and listening for a first mode signal. The first mode signal is described previously, in relation to process  302 , and will not be redundantly described here. 
         [0041]    When the vehicle  324  does not detect a first mode signal emitted by the remote device (the “No” branch of  328 ), the vehicle  324  continues to broadcast and listen for a first mode signal (step  326 ). When the vehicle detects a first mode signal emitted by the remote device (the “Yes” branch of  328 ), the vehicle  324  begins scanning for a remote wireless communication module (step  330 ). The result is described previously as it relates to process  302 : after the remote wireless communication module has transitioned to the active mode (step  312 ), the remote device advertises the presence of an internal wireless communication module (step  314 ). Concurrently, the vehicle scans appropriate advertising channels for the signal emitted by the remote wireless communication module (step  330 ). The signal advertising the presence of the remote device is a second mode signal, which may utilize any wireless communication standard, such as Bluetooth or Bluetooth Low Energy (BLE). The second mode signal is transmitted by a wireless communication module, which is separate and distinct from the first mode signal transceiver. 
         [0042]    Next, the vehicle uses the advertising signal transmitted by the remote device to determine whether the remote device is approaching the vehicle (step  332 ). The signal strength of the transmitted advertising signal is detected by a plurality of antennas on the vehicle, and the vehicle is able to use the data from the plurality of antennas to determine a distance from the vehicle to the remote device. In certain embodiments, the vehicle triangulates the position of the remote device over a period of time, and the vehicle compares each position to determine if the distance between the remote device and the vehicle is decreasing over time. When the distance is decreasing over time, it is determined that the remote device is approaching the vehicle. When the distance is not decreasing over time, it is determined that the remote device is not approaching the vehicle. 
         [0043]    In some implementations, the vehicle processes information from signals received by one of a plurality of antennas to determine signal strength information, and in some implementations, to determine the approximate distance between the source of those signals (e.g., the remote device) and the antenna. For example, when the plurality of antennas is implemented as a group of four Bluetooth antennas on the vehicle, the strength of a signal detected by one of the Bluetooth antennas is received, and is used by the vehicle to determine the approximate distance between the remote device and the particular Bluetooth antenna in use. In other words, signal strength information observed and determined at multiple sensors can be processed by the vehicle using known triangulation technologies to determine the approximate distance of an end device from one or more of the tires. In certain embodiments, a BLE sensor on the vehicle detects an advertised signal from a remote device, and uses received signal strength indication (RSSI) feedback to determine whether the remote device is approaching the vehicle. 
         [0044]    When it has been determined that the remote device is not approaching the vehicle (the “No” branch of  332 ), then the vehicle transmits a deactivation signal to the remote wireless communication module. This description assumes that the remote device receives the deactivation signal (step  316 ) and then transitions from the active mode to the low power mode (step  318 ). Thus, when the remote device is not approaching the vehicle, the vehicle sends a signal indicating that the internal wireless communication module of the remote device should power down, in order to conserve power, and the remote device returns to its “listening” mode, searching for a first mode signal emitted by the vehicle (step  304 ). 
         [0045]    When it has been determined that the remote device is approaching the vehicle (the “Yes” branch of  332 ), the vehicle determines if the remote device is within an authorized range (step  336 ) to establish a connection for communication. The authorized range is a distance value that is known to the vehicle process  324 , and the distance of the remote device determined at decision step  332 , using signal strength, is also used here to determine whether the remote device is located within the authorized range. 
         [0046]    Alternatively, any other link quality indicators, such as a Bluetooth proximity profile, can be used to determine the distance between two Bluetooth Low Energy (BLE) enabled devices, such as a BLE enabled remote device and a BLE enabled antenna. The proximity profile is defined in the BLE standard. The proximity profile uses a number of metrics including signal strength information, state of the battery charge, whether a device is connected, etc. to characterize the proximity of one BLE enabled device (e.g., a remote device to another BLE enabled device). 
         [0047]    When the remote device is not within the authorized range (the “No” branch of  336 ), the vehicle process  324  returns to scanning for an internal wireless communication module of the remote device within signal range (step  330 ). When the remote device is determined to be within an authorized range (the “Yes” branch of  336 ), the vehicle sends a connection signal for communication with the remote wireless communication module (step  338 ). As described previously, the remote device receives and accepts this connection signal (the “Yes” branch of  320 ). This establishes a connection for communication between the remote wireless communication module and the vehicle wireless communication module for the purpose of performing PEPS functionality. 
         [0048]    While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.