Patent Publication Number: US-2005143146-A1

Title: System and method for reducing power consumption by a telematic terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2003-0099268 filed on Dec. 29, 2003, the contents of which is hereby incorporated by reference in its entirety.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to the field of telematics, and more particularly to a system and method for reducing power consumption by a telematic terminal.  
      2. Description of the Related Art  
      The term “telematics” is an acronym for “telecommunication” and “informatics.” The term has evolved to refer to systems used in automobiles that combine wireless communication with GPS (Global Positioning System) tracking. GPS is a worldwide satellite navigational system formed by satellites that orbit the Earth at approximately 12,000 miles above the Earth&#39;s surface and make two complete orbits every 24 hours. The GPS satellites continuously transmit digital radio signals containing data on orbital location and exact time to Earth-bound receivers.  
      The term “telematics” has further evolved to refer to telecommunication functionality that originates or terminates in transportation vehicles. Lately, telematics has been receiving much attention in the field of information technology (IT). Particularly, an automobile equipped with an on-board telematic terminal can provide the driver with a wide variety of up-to-date information on car accidents, crime prevention, road and traffic conditions, or the like in real-time. The telematic terminal can wirelessly establish communication with an automobile service center when a traveling vehicle unexpectedly breaks down on the road.  
      Telematic terminals can also receive and display road map data via an on-board display unit, allow passengers to play computer games via a portable computer monitor installed in the back seats, and provide status information on major components of the vehicle to a central automobile service facility. Telematic terminals also allow a driver to use the Internet via voice commands while driving. Such a terminal can help locked-out drivers gain access to their vehicles by receiving and acting on a satellite “door unlock” signal from a vehicle service center.  
       FIG. 1  is a block diagram of a conventional telematic terminal  10 . Telematic terminal  10  includes a NAD (Network Access Device) processor  11 , a NAD power supply  12 , a terminal controller  13 , and a CIU (Communication Interface Unit)  15 . NAD processor  11  is configured to process various call signals between a base station and the terminal using mobile (wireless) communication technology, as well as modulate/demodulate data signals. Terminal controller  13  is operatively coupled between CIU  15  and NAD processor  11 , and is powered by a main power supply  16  ( FIG. 1 ).  
      Terminal controller  13  communicates with NAD processor  11  via a UART (Universal Asynchronous Receiver Transmitter) connection. A software (S/W) timer  13   a  in terminal controller  13  is driven by a clock oscillator  14  ( FIG. 1 ). A keep-alive power supply  18  supplies power to CIU  15  and a communication signal amplifier  17  ( FIG. 1 ).  
      CIU  15  includes a CAN (Controller Area Network) physical layer interface  15   a  and a J1850 physical layer interface  15   b , and is configured as a Class 2 Series communication device. Main power supply  16  is controlled by a communication signal combiner  19  which receives input from CIU  15  and communication signal amplifier  17 .  
      Telematic terminal  10  operates in a reception standby power saving mode after the ignition of a vehicle equipped with telematic terminal  10  is turned off. In the reception standby power saving mode, operation is performed in ten-minute intervals whereby communication signals are being received from a base station for one minute after the ignition of the car is turned off with no communication signals being received from the base station for the remaining nine minutes. Such operation is performed continuously to limit power consumption as much as possible, as well as to extend the life of the vehicle battery or other power storage devices, such as the battery of the telematic terminal.  
      Specifically, NAD processor  11  receives current time information from a CDMA (Code Division Multiple Access)/PCS (Personal Communications Service) base station (not shown) and transmits the received time information to terminal controller  13 . If the vehicle ignition is turned off, clock oscillator  14  drives software timer  13   a  whereby terminal controller  13  implements a power saving mode periodically according to a pre-set timing. In a reception standby state, terminal controller  13 , NAD processor  11  and a RF (Radio Frequency) module (not shown) are driven for one minute to receive communication signals transmitted from the base station. For the remaining nine minutes, only the NAD processor core, the RF module core and the terminal controller core are driven in a power saving mode.  
      The simultaneous operation of terminal controller  13 , NAD processor  11  and the RF module during a reception standby state causes large amounts of current to be consumed due to software timer  13   a  being integrated in terminal controller  13 . However, vehicle battery capacity is somewhat limited. Thus, on-board telematic terminal  10  cannot operate for a prolonged period of time without draining the vehicle battery.  
     SUMMARY OF THE INVENTION  
      In accordance with one aspect of the present invention, a system for reducing power consumption by a telematic terminal comprises a NAD (Network Access Device) processor having at least one processor core, a CIU (Communication Interface Unit), and a telematic terminal controller operatively coupled between the CIU and the NAD processor on board a vehicle. The telematic terminal controller and the NAD processor core are configured to be turned off and driven, respectively, in a power saving mode when the vehicle ignition is turned off. The power saving mode changes into a signal reception standby state after a pre-set period of time.  
      The NAD processor is adapted to operate normally during the signal reception standby state, whereby only the NAD processor core and an associated RF (Radio Frequency) module core are driven for the pre-set period of time when the vehicle ignition is turned off.  
      A first power supply is adapted to power the telematic terminal controller. The first power supply is controlled by a communication signal combiner which receives input from the CIU, the NAD processor and at least one communication signal amplifier.  
      A second power supply is adapted to power the NAD processor. The second power supply is turned on by the telematic terminal controller. The NAD processor includes a software timer being driven by a clock oscillator. The clock oscillator is operatively coupled to the NAD processor. The NAD processor drives the software timer based on time information transmitted from a base station and the clock oscillator during the power saving mode.  
      A third power supply is adapted to power the CIU and the communication signal amplifier. The third power supply may be a keep-alive power supply. The CIU may include at least one CAN (Controller Area Network) physical layer interface and at least one J1850 physical layer interface. The CIU may be configured as a Class 2 Series communication device. The telematic terminal controller communicates with the NAD processor via a UART (Universal Asynchronous Receiver Transmitter) connection.  
      In accordance with another aspect of the present invention, a system for reducing power consumption by a telematic terminal comprises a NAD (Network Access Device) processor having a core, a CIU (Communication Interface Unit), a PMIC (Power Management Integrated Circuit) having a core, and a telematic terminal controller operatively coupled between the CIU and the NAD processor on board a vehicle and being powered by the PMIC. The telematic terminal controller and the NAD and PMIC cores are configured to be turned off and driven, respectively, in a power saving mode when the vehicle ignition is turned off.  
      The power saving mode changed into a signal reception standby state after a pre-set period of time. The NAD processor and the PMIC operate normally during the signal reception standby state, whereby only the NAD and PMIC cores and an associated RF (Radio Frequency) module core are driven for the pre-set period of time when the vehicle ignition is turned off.  
      The PMIC includes a RTC (Real-Time Clock) unit. The PMIC is turned on by the telematic terminal controller. The PMIC drives the RTC unit based on time information received from the NAD processor and a clock oscillator that is operatively coupled to the PMIC. The NAD processor is configured to periodically change the reception standby state to the power saving mode on the basis of real-time information received from the RTC unit. The telematic terminal controller communicates with the NAD processor via a UART (Universal Asynchronous Receiver Transmitter) connection.  
      A first power supply is adapted to power the telematic terminal controller. The first power supply is controlled by a communication signal combiner which receives input from the CIU, the NAD processor and at least one communication signal amplifier.  
      A second power supply is adapted to power the CIU and the communication signal amplifier. The second power supply may be a keep-alive power supply. The CIU may include at least one CAN (Controller Area Network) physical layer interface and at least one J1850 physical layer interface. The CIU may be configured as a Class 2 Series communication device.  
      In accordance with yet another aspect of the present invention, a method for reducing power consumption by a telematic terminal on board a vehicle comprises: 
          turning off a telematic terminal controller to save power after the vehicle ignition is turned off;     driving only the cores of a NAD (Network Access Device) processor and a RF (Radio Frequency) module for a first pre-set period of time in a power saving mode;     checking whether the first pre-set period of time has elapsed;     changing into a reception standby state from the power saving mode if the first pre-set period of time has elapsed, the NAD processor and the RF module operating normally during the reception standby state for a second pre-set period of time;     checking whether the second pre-set period of time has elapsed;     checking whether the vehicle ignition has been turned on if the second pre-set period of time has elapsed; and     turning on the telematic terminal controller if the vehicle ignition has been turned on. The turned on telematic terminal controller terminates the reception standby state.        

      The method further comprises changing into the power saving mode again if the vehicle ignition has not been turned on.  
      In accordance with still another aspect of the present invention, a method for reducing power consumption by a telematic terminal on board a vehicle comprises: 
          turning off a telematic terminal controller to save power after the vehicle ignition is turned off;     driving a RTC (Real-Time Clock) unit;     driving only the cores of a NAD (Network Access Device) processor, a RF (Radio Frequency) module, and a PMIC (Power Management Integrated Circuit) for a first pre-set period of time in a power saving mode, the RTC unit being integrated in the PMIC;     checking whether the first pre-set period of time has elapsed;     transmitting real-time information from the PMIC to the NAD processor if the first pre-set period of time has elapsed;     changing into a reception standby state from the power saving mode, the NAD processor, the RF module, and the PMIC operating normally during the reception standby state for a second pre-set period of time;     checking whether the second pre-set period of time has elapsed;     checking whether the vehicle ignition has been turned on if the second pre-set period of time has elapsed; and     turning on the telematic terminal controller if the vehicle ignition has been turned on. The turned on telematic terminal controller terminates the reception standby state.        

      The method further comprises changing into the power saving mode again if the vehicle ignition has not been turned on.  
      These and other aspects of the present invention will become apparent from a review of the accompanying drawings and the following detailed description of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention is generally shown by way of reference to the accompanying drawings as follows.  
       FIG. 1  is a block diagram of a conventional telematic terminal.  
       FIG. 2  is a block diagram of a telematic terminal in accordance with one embodiment of the present invention.  
       FIG. 3  is an exemplary operational flow chart of the telematic terminal of  FIG. 2 .  
       FIG. 4  is a block diagram of a telematic terminal in accordance with another embodiment of the present invention.  
       FIG. 5  is an exemplary operational flow chart of the telematic terminal of  FIG. 4 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Some embodiments of the present invention will be described in detail with reference to the related drawings of  FIGS. 2-5 . Additional embodiments, features and/or advantages of the invention will become apparent from the ensuing description or may be learned by practicing the invention.  
      In the figures, the drawings are not to scale with like numerals referring to like features throughout both the drawings and the description.  
      The following description includes the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention.  
       FIGS. 2-5  generally depict a system and method for reducing power consumption by a telematic terminal in accordance with the general principles of the present invention.  FIG. 2  is a block diagram of a telematic terminal  20  in accordance with one embodiment of the present invention.  
      Telematic terminal  20  includes a terminal controller  21 , a NAD processor  22 , a NAD power supply  24 , and a CIU (Communication Interface Unit)  23 . CIU  23  includes a CAN (Controller Area Network) physical layer interface  23   a  and a J1850 physical layer interface  23   b , and is configured as a Class 2 Series communication device. NAD processor  22  is configured to process various call signals between a base station and the terminal using mobile (wireless) communication technology, as well as modulate/demodulate data signals. Terminal controller  21  is operatively coupled between CIU  23  and NAD processor  22 , and is powered by a main power supply  25 . NAD power supply  24  is turned on by terminal controller  21  ( FIG. 2 ).  
      Terminal controller  21  communicates with NAD processor  22  via a UART connection. A software (S/W) timer  22   a  in NAD processor  22  is driven by a clock oscillator  27  ( FIG. 2 ). A keep-alive power supply  26  supplies power to CIU  23  and a communication signal amplifier  29 . Main power supply  25  is controlled by a communication signal combiner  28  which receives input from CIU  23 , communication signal amplifier  29 , and NAD processor  22 . NAD processor  22  may be implemented as a modem adapted for mobile communication, also referred to as MSM (Mobile Station Modem).  
      When the ignition of a vehicle equipped with telematic terminal  20  is turned off, terminal controller  21  is completely turned off. With ignition being turned off, NAD processor  22  drives software timer  22   a  based on time information transmitted from the base station (not shown) and clock oscillator  27 , which is operatively coupled to NAD processor  22 . By using its internal software timer  22   a , NAD processor  22  drives itself and a RF module (not shown) for a predetermined initial period of time (e.g., one minute) with on-board telematic terminal  20  operating in a reception standby state. On-board telematic terminal  20  drives only the NAD processor core and the RF module core for a predetermined final period of time (e.g., nine minutes) to save power, i.e. on-board telematic terminal  20  is in a power saving mode.  
      If on-board telematic terminal  20  is located in an analog service region where time information cannot be obtained from a base station, software timer  22   a  uses time input from a satellite through an integral GPS module. With NAD processor  22  and the RF module being in a reception standby state for one minute, and only the cores of NAD processor  22  and the RF module being driven in a power saving mode for the remaining nine minutes, the overall amount of current being consumed is significantly reduced (compared to the telematic setup of  FIG. 1 ), since terminal controller  21  is completely turned off.  
       FIG. 3  is an exemplary operational flow chart of telematic terminal  20 . When the ignition of a car equipped with an on-board telematic terminal, such as terminal  20 , is turned off (step  40 ), terminal controller  21  is completely turned off, with software timer  22   a  operating on the basis of time information received from a CDMA/PCS base station (not shown) (step  42 ). While software timer  22   a  is operative, on-board telematic terminal  20  goes into a power saving mode (step  44 ). In the power saving mode, only the NAD processor core and the RF module core are being driven (step  46 ).  
      If the power saving mode lasts longer than a pre-set period of time, e.g. nine minutes (step  48 ), on-board telematic terminal  20  changes into a reception standby state (step  50 ), in which NAD processor  22  and the RF module operate normally. If the power saving mode does not last longer than the pre-set period of time, on-board telematic terminal  20  remains in power saving mode and repeats step  46  ( FIG. 3 ).  
      If the reception standby state lasts longer than a pre-set period of time, e.g. one minute (step  52 ), on-board telematic terminal  20  checks whether the car ignition has been turned on (step  54 ). If the reception standby state does not last longer than the pre-set period of time, on-board telematic terminal  20  repeats step  50  ( FIG. 3 ).  
      If the ignition has not been turned on, on-board telematic terminal  20  changes into power saving mode again, i.e. repeats step  44 . If the ignition is turned on, the reception standby state of on-board telematic terminal  20  is terminated, and terminal controller  21  is turned on (step  56 ). A person skilled in the art would readily appreciate that the above-identified time periods may be adjusted, as necessary. A person skilled in the art would also appreciate that telematic terminal  20  advantageously reduces overall power consumption by completely turning terminal controller  21  off after the car ignition has been turned off. Consequently, only NAD processor  22  and the RF module (not shown) are periodically turned on to receive signals from the base station according to the general principles of the present invention.  
       FIG. 4  is a block diagram of a telematic terminal  30  in accordance with another embodiment of the present invention. Telematic terminal  30  includes a terminal controller  33 , a NAD processor  31 , a PMIC (Power Management Integrated Circuit)  32 , and a CIU (Communication Interface Unit)  34 . CIU  34  includes a CAN (Controller Area Network) physical layer interface  34   a  and a J1850 physical layer interface  34   b , and is configured as a Class 2 Series communication device. Terminal controller  33  is operatively coupled between CIU  34  and NAD processor  31 , and is powered by a main power supply  35 .  
      PMIC  32  supplies power to terminal controller  33  and includes a RTC (Real-Time Clock) unit  32   a . PMIC  32  is turned on by terminal controller  33  ( FIG. 4 ). PMIC  32  includes a plurality of power regulators which control the supply power to NAD processor  31  and a RF module (not shown). PMIC  32  drives RTC unit  32   a  based on time information received from NAD processor  31  and a clock oscillator (not shown) operatively coupled to PMIC  32 . NAD processor  22  is configured to process various call signals between a base station and the terminal using mobile (wireless) communication technology, as well as modulate/demodulate data signals. NAD processor  31  periodically changes the mode of operation of telematic terminal  30  from reception standby state to power saving mode on the basis of real-time information received from RTC unit  32   a.    
      Terminal controller  33  communicates with NAD processor  31  via a UART connection. A keep-alive power supply  36  supplies power to CIU  34  and a communication signal amplifier  37 . Main power supply  35  is controlled by a communication signal combiner  38  which receives input from CIU  34 , communication signal amplifier  37 , and NAD processor  31 . NAD processor  31  may be implemented as a modem adapted for mobile communication, also referred to as MSM (Mobile Station Modem).  
       FIG. 5  is an exemplary operational flow chart of telematic terminal  30 . When the ignition of a car equipped with an on-board telematic terminal, such as terminal  30 , is turned off (step  60 ), terminal controller  33  is completely turned off (step  62 ). NAD processor  31  transmits time information received from a base station (not shown) to PMIC  32  which presets RTC unit  32   a . RTC unit  32   a  is driven according to the transmitted time information, and on-board telematic terminal  30  goes into a power saving mode (step  64 ) with the exception of RTC unit  32   a . In the power saving mode, only the NAD processor core, the RF module core and the PMIC core are being driven (step  66 ).  
      If the power saving mode lasts longer than a pre-set period of time, e.g. nine minutes (step  68 ), PMIC  32  transmits real-time information to NAD processor  31  (step  70 ), which is turned on. Consequently, on-board telematic terminal  30  changes into a reception standby state (step  72 ), in which NAD processor  31 , the RF module and PMIC  32  operate normally. If the power saving mode does not last longer than the pre-set period of time, on-board telematic terminal  30  remains in power saving mode and repeats step  66  ( FIG. 5 ).  
      If the reception standby state lasts longer than a pre-set period of time, e.g. one minute (step  74 ), on-board telematic terminal  30  checks whether the car ignition has been turned on (step  76 ). If the reception standby state does not last longer than the pre-set period of time, on-board telematic terminal  30  repeats steps  70  and  72  ( FIG. 5 ).  
      If the ignition has not been turned on, on-board telematic terminal  30  changes into power saving mode again, i.e. repeats step  64 . If the ignition is turned on, the reception standby state of on-board telematic terminal  30  is terminated, and terminal controller  33  is turned on (step  78 ).  
      A person skilled in the art would readily appreciate that the above-identified time periods may be adjusted, as necessary. A person skilled in the art would also appreciate that power consumption used to operate terminal controller  33  in the reception standby state, as practiced in the telematic setup of  FIG. 1 , is completely eliminated, thereby minimizing battery consumption of telematic terminal  30  and extending its life.  
      When the car ignition is turned off, terminal controller  33  is completely turned off. Subsequently, only NAD processor  31  and the RF module are turned on periodically to receive communication signals from the base station.  
      All terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.  
      While the present invention has been described in detail with regards to several embodiments, it should be appreciated that various modifications and variations may be made in the present invention without departing from the scope or spirit of the invention. In this regard it is important to note that practicing the invention is not limited to the applications described hereinabove.  
      Many other applications and/or alterations may be utilized provided that such other applications and/or alterations do not deviate from the intended purpose of the present invention. Also, features illustrated or described as part of one embodiment can be used in another embodiment to provide yet another embodiment such that the features are not limited to the embodiments described above. Thus, it is intended that the present invention cover all such embodiments and variations as long as such embodiments and variations come within the scope of the appended claims and their equivalents.