Abstract:
A method for controlling extension of an antenna in a communications device. The communications device contains an antenna capable of being extended. The method includes detecting occurrence of an event selected from a group consisting of: starting a radio frequency (RF) spectrum scan, starting a data packet transfer, entering a discontinuous reception (DRX) wake up mode, starting a phone call, and starting an emergency phone call. In response to the detection of the event, the method also includes causing the antenna to be extended. The antenna can be extended manually or extended automatically with a motor.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a mobile communications device with an extendable antenna, and more specifically, to a method for extending and retracting the extendable antenna in response to an event.  
           [0003]    2. Description of the Prior Art  
           [0004]    Mobile stations such as cellular phones commonly use an extendable antenna to improve reception and transmission of signals. Please refer to FIG. 1A and FIG. 1B. FIG. 1A is a diagram of a prior art mobile station  10  with an antenna  12  in a retracted state. FIG. 1B is a diagram of the mobile station  10  with the antenna  12  in an extended state. To go from the retracted state to the extended state, the antenna  12  can be pulled in direction  16 . On the other hand, to go from the extended state to the retracted state, the antenna  12  can be pushed in direction  14 . Extending and retracting the antenna  12  affects a Received Signal Strength Indicator (RSSI) level of signals received by the mobile station  10 .  
           [0005]    The mobile station  10  uses the antenna  12  to transmit signals to and receive signals from base stations. In order to reduce interference effects between received signals and transmitted signals, the transmitted signals are designed to be much stronger than the received signals. The range of the RSSI for received signals varies from −70 dBm to −104 dBm in CDMA. When the RSSI level is close to −104 dBm, the chance of call drop increases. Therefore, by increasing the RSSI level, the call drop problem can be improved. One possibility of increasing the RSSI level is to extend the antenna  12  of the mobile station  10 . However, this is only a solution for mobile stations that have an extendable antenna.  
           [0006]    Please refer to FIG. 2. FIG. 2 is a chart comparing RSSI signals when the antenna  12  is retracted and extended. Signal  20  shows the RSSI level when the antenna  12  is retracted, and signal  22  shows the RSSI level when the antenna  12  is extended. Each of these signals  20 ,  22  was recorded in a laboratory, and compares the RSSI levels (measured in dBm) over time (measured in seconds). Based on the laboratory test results, extending the antenna  12  can increase the RSSI level from several dBm to over 10 dBm. This improvement can help to reduce the call drop rate. In addition, the improvement in RSSI level also allows the mobile station  10  to increase a base station paging rate, in which the mobile station  10  pages different channel frequencies to see if a channel with better reception is available.  
           [0007]    With modern mobile stations, size of the mobile station  10  is a common concern. Therefore, the manufacturer of the mobile station  10  will often hide the antenna  12  when it is not needed. For this kind of design, it is assumed that users of the mobile station  10  will extend the antenna  12  when they need the antenna  12  and retract it when it is not needed. However, users of the mobile station  10  often forget to extend the antenna  12 , and transmission quality will be affected accordingly.  
           [0008]    In order to solve this problem, many proposals have been introduced. In U.S. Pat. No. 6,301,469 B1, Kim teaches a “Method for automatically switching antenna mode in portable telephone”, which is herein incorporated by reference. Please refer to FIG. 3A and FIG. 3B. FIG. 3A and FIG. 3B are diagrams of a prior art mobile station  30  having a motor  34  for controlling extension and retraction of an antenna  32 . FIG. 3A is a diagram of the mobile station  30  with the antenna  32  in a retracted state. FIG. 3B is a diagram of the mobile station  30  with the antenna  32  in an extended state. The mobile station  30  also contains a display  36 , such as an LCD, and a speaker  38 . To go from the retracted state to the extended state, the motor  34  extends the antenna  32  in direction  16 . On the other hand, to go from the extended state to the retracted state, the motor  34  retracts the antenna  32  in direction  14 . The mobile station  30  is capable of automatically extending or retracting the antenna  32  with the aid of the motor  34 . Therefore, the user of the mobile station  30  does not need to manually extend or retract the antenna  32 , eliminating the potential for the user to forget to extend the antenna  32  and to experience call drop.  
           [0009]    Please refer to FIG. 4. FIG. 4 is a flowchart of a prior art method for extending and retracting the antenna  32  of the mobile station  30 . Steps contained in the flowchart will be explained below.  
           [0010]    Step  50 : Start a phone call;  
           [0011]    Step  52 : Determine if the antenna  32  is retracted; if so, go to step  54 ; if not, go to step  66 ;  
           [0012]    Step  54 : Determine if an antenna switching control function has been set. A user can set this control function to enable the automatic extension of the antenna  32 ; if so, go to step  54 ; if not, go to step  66 ;  
           [0013]    Step  56 : Measure the RSSI level of the mobile station  30 ;  
           [0014]    Step  58 : Determine if the RSSI level is less than a threshold value; if so, go to step  60 ; if not, go to step  56 ;  
           [0015]    Step  60 : Since the RSSI level was below the threshold value, the motor  34  extends the antenna  32 ;  
           [0016]    Step  62 : Determine if the call has been terminated; if so, go to step  64 ; if not, go back to step  56 ;  
           [0017]    Step  64 : Since the call has been terminated, the motor  34  retracts the antenna  32 ;  
           [0018]    Step  66 : End.  
           [0019]    The prior art method shown in FIG. 4 is used for automatically extending and retracting the antenna  32  with the motor  34 . Unfortunately, prior art method requires the mobile station  30  to have the motor  34  installed, adding to the size of the mobile station  30 . In addition, the antenna  32  is only extended during a phone call, and not when other events that may also benefit from a higher RSSI level are performed.  
         SUMMARY OF INVENTION  
         [0020]    It is therefore a primary objective of the claimed invention to provide a method for extending and retracting an extendable antenna of a communications device in response to an event in order to solve the above-mentioned problems.  
           [0021]    According to the claimed invention, a method for controlling extension of an antenna in a communications device is provided. The communications device contains an antenna capable of being extended. The method includes detecting occurrence of an event selected from a group consisting of: starting a radio frequency (RF) spectrum scan, starting a data packet transfer, entering a discontinuous reception (DRX) wake up mode, starting a phone call, and starting an emergency phone call. In response to the detection of the event, the method also includes causing the antenna to be extended.  
           [0022]    It is an advantage of the claimed invention that the communications device does not require a motor to be installed for extending and retracting an antenna of the communications device. In addition, the claimed invention method extends the antenna for a number of events, and it not limited to extending the antenna only at the start of phone calls.  
           [0023]    These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0024]    [0024]FIG. 1A is a diagram of a prior art mobile station with an antenna in a retracted state.  
         [0025]    [0025]FIG. 1B is a diagram of the mobile station with the antenna in an extended state.  
         [0026]    [0026]FIG. 2 is a chart comparing RSSI signals when the antenna is retracted and extended.  
         [0027]    [0027]FIG. 3A and FIG. 3B are diagrams of a prior art mobile station having a motor for controlling extension and retraction of an antenna.  
         [0028]    [0028]FIG. 4 is a flowchart of a prior art method for extending and retracting the antenna of the mobile station.  
         [0029]    [0029]FIG. 5 is a functional block diagram of a mobile station according to the present invention.  
         [0030]    [0030]FIG. 6 is a block diagram of software used to control the mobile station.  
         [0031]    [0031]FIG. 7 is a flowchart of a present invention method for extending and retracting the antenna of the mobile station.  
         [0032]    [0032]FIG. 8 is a chart comparing RSSI signals when the mobile station is held in left or right hands. 
     
    
     DETAILED DESCRIPTION  
       [0033]    Please refer to FIG. 5. FIG. 5 is a functional block diagram of a mobile station  100  according to the present invention. The mobile station  100  comprises a motor  104  for extending and retracting an antenna  102 , a speaker  108  for producing audible tones, and a display  106  such as an LCD for displaying messages. A control unit  110  is used for controlling operation of the speaker  108 , motor  104 , and display  106 . The mobile station  100  also contains a memory  112  for storing programs and data used by the mobile station  100 .  
         [0034]    Please refer to FIG. 6. FIG. 6 is a block diagram of software used to control the mobile station  100 . Installed in the memory  112  is a control unit application program interface (API)  116  used for allowing software to communicate with the control unit  110 . In addition, the memory  112  also contains protocol software  114 , which controls the control unit  110  through the control unit API  116 . As will be explained below, when the protocol software  114  detects a certain group of events and conditions, the protocol software  114  sends an extend or retract signal to the control unit API  116 , which in turn sends the signal to the control unit  110 .  
         [0035]    The present invention method is capable of being used in mobile stations with or without motors. The mobile station  100  shown in FIG. 5 illustrates all features of the present invention, and will be used in the description below. To fully appreciate the advantages of the present invention, it is necessary to first look at situations in which it is desired to extend and retract the antenna  102 .  
         [0036]    During a scan of the entire radio frequency (RF) spectrum, the mobile station  100  is interested in measuring RSSI signals from a potential base station and collecting system information from chosen broadcast channels. Thus, during this time, the mobile station  100  will not launch any paging receiving action. The mobile station  100  will start to receive paging messages from the network if it has successfully registered into a suitable cell. When there are some up link and/or down link activities between the mobile station  100  and the network, the mobile station  100  is in the packet transfer mode.  
         [0037]    It is desirable to extend the antenna  102  in both the entire RF scan state and the packet transfer state. It should be noted that extending the antenna  102  at the beginning of the RF scan is most useful for mobile stations using the Global System for Mobile Communications (GSM) standard, but can also be used mobile stations that use other communication standards. During the entire RF scan state, the mobile station  100  needs to measure all the frequencies in every band of the RF spectrum in a very short period of time. Then, the mobile station  100  needs to identify broadcasting channels among these strongest frequencies and decode the corresponding system information in a given period. In order to calculate a better measurement result and find more available base stations, extending the antenna  102  will be very beneficial. During the packet transfer state, it is crucial to receive correct data. Thus, having the antenna  102  extended will help to eliminate unnecessary noise. The extended antenna  102  will also make layer 1 scheduling work better in the packet transfer state, because there are other neighbor cell measuring activities that need to be performed during the packet transfer state. Furthermore, the increased dBm gained by using the extended antenna  102  will help the cell change to be done in a graceful way in the packet transfer state. Likewise, during a discontinuous reception (DRX) wake up mode, the mobile station  100  performs a cell reselection function. As a result, it is recommended to extend the extra antenna  102  at the beginning of an RF Scan, when starting a packet transfer, and when entering a DRX wake up mode. It is also recommended to retract the antenna  102  at the end of each of these three events.  
         [0038]    The antenna  102  can retract and extend during voice transmissions as well as the other aforementioned mandatory cases. The extended antenna  102  during this scenario will reduce the call drop rate. The antenna  102  can be fully extended in areas where the signal strength is too low and retract when it is not needed. The scenarios related to the signal strength being too low can further be divided into the signal strength of the serving cell being too low or the signal strength of at least one of the six strongest neighbor cells being too low. The former scenario requires that the antenna  102  is extended during the voice or data transaction between the mobile station  100  and the serving cell. The latter scenario requires that the antenna  102  is extended during the cell selection and reselection process proceeded in the DRX wake up mode, where the extended antenna  102  may help to collect a better measurement result from the neighbor cells during a measurement process.  
         [0039]    As discussed above, the protocol software  114  can be used to decide whether the antenna  102  should be extended or retracted. When this scheme is applied to work with the motor  104  to make the antenna  102  to be extended and retracted in an automatic way, the user of the mobile station  100  is given the option to disable the automatic antenna  102  temporarily if needed. For example, if the mobile station  100  is used with a hands-free device or secured via a belt clip, it might be desirable to disable the antenna  102  from being extended and retracted with the motor  104 . In addition to simply enabling or disabling the automatic antenna  102 , the user could also choose to disable extension and retraction of the antenna  102  during voice calls, packet transfers, RF scans, or during any other events.  
         [0040]    During DRX mode, the RSSI level is continuously monitored in the cell reselection process. If the RSSI level falls below a certain value and becomes too low, the protocol software  114  sends an “extend” command to the control unit  110  for extending the antenna  102  to achieve a higher RSSI level, and the protocol software  114  will send the “retract” command to the control unit  110  when the routine measurement process is finished.  
         [0041]    When the user of the mobile station  100  has made an emergency call, such as calling “911”, it is recommended to keep the antenna  102  in the extended position for a certain period of time after the call has been terminated. This is done to allow easier tracking of the mobile station  100  user by law enforcement authorities.  
         [0042]    When a mobile station  100  is using a suitable cell, the cell reselection algorithm will be executed routinely. The cell reselection algorithm will measure both the RSSI level of the serving cell and neighbor cells to see whether the serving cell encounters a path loss problem or whether there is a better neighbor cell with a stronger signal than the serving cell. When either case occurs, the serving cell may be changed. As seen in FIG. 2, even when the mobile station  100  is stationary, the RSSI levels vary from time to time. When the mobile station  100  is in a moving state and its value is lower than a given value specified by communications protocols such as GSM, the serving cell will be changed. If a neighbor cell is not changed in time, the service will be terminated. In order to make a graceful transition between the old serving cell and the new serving cell, a proposed scheme considers a running average value of the RSSI. Let the running average value be defined as RVA. If the current RVA value is less than a path loss value C1 plus a threshold value Td value given by the manufacturer, the protocol software  114  will send a signal to indicate that the antenna  102  should be extended.  
         [0043]    The present invention method can be used to extend or retract the antennas of mobile stations regardless of whether they contain a motor. For instance, assume that the mobile station  100  contains the motor  104 . The control unit  110  is electrically connected to the motor  104 , as shown in FIG. 5. When an “extend” command arrives at the control unit  110 , the antenna  102  will be extended automatically with the assistance of the motor  104 . When a “retract” command arrives at the control unit  110 , the extended antenna  102  will be retracted automatically with the assistance of the motor  104 . As mentioned before, the mobile station  100  users can override or disable the motor  104  functionality temporarily if they have special purposes of doing so. Also, should the antenna  102  be obstructed by any type of force during extension or retraction, the control unit  110  stops sending signals to the motor momentarily. The control unit  110  then notifies the user with a sound of an alarm through the speaker  108  and/or a message on the display  106  that the antenna  102  could not function properly or could not be extended. The control unit  110  then repeats the extension or retraction process after a predetermined time period.  
         [0044]    Even if the mobile station  100  does not contain the motor  104 , the present invention method could still be used to notify users that the antenna  102  should be extended or retracted. For example, when the control unit  110  receives an “extend” message from the protocol software  114 , the control unit  110  can show a corresponding message on the display  106  to remind the users that they should extend the antenna  102 . In addition to or instead of showing a message on the display  106 , the control unit  110  can also produce an alarm tone through the speaker  108  to attract the user″s attention. Similarly, the display  106  and/or the speaker  108  can also be used to notify the user that the antenna  102  should be retracted.  
         [0045]    Please refer to FIG. 7. FIG. 7 is a flowchart of a present invention method for extending and retracting the antenna  102  of the mobile station  100 . The mobile station  100  will extend or retract the antenna  102  in response to a number of events. Steps contained in the flowchart will be explained below.  
         [0046]    Step  200 : Start;  
         [0047]    Step  202 : Determine if an RF scan process has started; if so, go to step  212 ; if not, go to step  204 ;  
         [0048]    Step  204 : Determine if the mobile station  100  has entered a packet transfer state; if so, go to step  212 ; if not, go to step  206 ;  
         [0049]    Step  206 : Determine if the mobile station  100  has entered a DRX wake up mode; if so, go to step  212 ; if not, go to step  208 ;  
         [0050]    Step  208 : Determine if a phone call has started; if so, go to step  212 ; if not, go to step  210 ;  
         [0051]    Step  210 : Determine if a running average value RVA of the RSSI has been less than a path loss value C1 plus a threshold value Td for a predetermined period of time, such as 5 seconds; if so, go to step  212 ; if not, go to step  216 ;  
         [0052]    Step  212 : Determine if the antenna  102  is already extended; if so, go to step  234 ; if not, go to step  214 ;  
         [0053]    Step  214 : The protocol software  114  sends an “extend” signal to the control unit  110 . The control unit  110  can automatically extend the antenna  102  with the motor  104 , show a message on the display  106 , or produce an audible tone with the speaker  108  to notify the user to extend the antenna  102 ; go to step  234 ;  
         [0054]    Step  216 : Determine if an RF scan process has ended; if so, go to step  226 ; if not, go to step  218 ;  
         [0055]    Step  218 : Determine if the mobile station  100  has left a packet transfer state; if so, go to step  226 ; if not, go to step  220 ;  
         [0056]    Step  220 : Determine if the mobile station  100  has entered a DRX sleep mode; if so, go to step  226 ; if not, go to step  222 ;  
         [0057]    Step  222 : Determine if the running average value RVA of the RSSI has been greater than the path loss value C1 plus the threshold value Td for the predetermined period of time, such as 5 seconds; if so, go to step  226 ; if not, go to step  223 ;  
         [0058]    Step  223 : Determine if a phone call has ended; if so, go to step  224 ; if not, go to step  234 ;  
         [0059]    Step  224 : Determine if an emergency call was made, such as dialing “911”; if so, go to step  225 ; if not, go to step  226 ;  
         [0060]    Step  225 : Determine if the emergency call been complete for longer than a predetermined period of time T; if so, go to step  226 ; if not, the antenna should continue to be extended, go to step  234 ;  
         [0061]    Step  226 : Determine if the antenna  102  is already retracted; if so, go to step  234 ; if not, go to step  228 ;  
         [0062]    Step  228 : Determine if an emergency call was made, such as dialing “911”; if so, go to step  230 ; if not, go to step  232 ;  
         [0063]    Step  230 : Determine if the emergency call been complete for longer than a predetermined period of time T; if so, the antenna should be retracted, go to step  232 ; if not, the antenna should continue to be extended, go to step  234 ;  
         [0064]    Step  232 : The protocol software  114  sends a “retract” signal to the control unit  110 . The control unit  110  can automatically retract the antenna  102  with the motor  104 , show a message on the display  106 , or produce an audible tone with the speaker  108  to notify the user to retract the antenna  102 ; go to step  234 ;  
         [0065]    Step  234 : End.  
         [0066]    When the mobile station  100  users are in a conversation with another party through the mobile station  100 , sometimes they may perceive that the quality of received signals varies according to which hand they use to hold the mobile station  100 . Please refer to FIG. 8. FIG. 8 is a chart comparing RSSI signals when the mobile station is held in left or right hands. Signal  120  shows the RSSI level when the mobile station  100  is held in the right hand, and signal  122  shows the RSSI level when the mobile station  100  is held in the left hand.  
         [0067]    [0067]FIG. 8 contains data from a test result taken in a laboratory, and indicates that the difference in the received RSSI from using the right hand or the left hand for holding the same mobile station  100  can vary up to 8 dBm. This is mainly because part of the signals transmitted from the camped base station is blocked by the mobile station  100  user″s body. In order to alleviate this kind of problem, the present invention method proposes a solution.  
         [0068]    Assume that right after the antenna  102  is extended, the RSSI level is still considered too low and the mobile station  100  cannot find a better cell to replace the current serving cell. The mobile station  100  can show a message “Please change the mobile station receiving location to improve the receiving signal quality” on the display  106  of the mobile station  100  with optional audio effects played through the speaker  108  so as to attract the mobile station  100  user″s attention. When the mobile station  100  users receive this message, they can either switch the hand used to hold the mobile station  100 , or move to a more open space area to improve the RSSI level. This feature is helpful in reducing the call drop rate, and is especially important when calling an emergency number when the mobile station  100  is in an area with poor signal reception. Since this feature relies on the display  106  and the speaker  108  for alerting the user, this feature can be used on mobile stations with or without an antenna.  
         [0069]    Compared to the prior art method of automatically extending and retracting the antenna with the motor, the present invention method is much more versatile. The prior art method requires a motor to be installed in the mobile station, adding to the size of the mobile station. In addition, the prior art method only extends the antenna when the RSSI level is too low during a phone call. On the other hand, the present invention method does not require the mobile station to contain a motor, and instead can notify users that the antenna should be extended or retracted through a display and a speaker. Furthermore, the present invention method extends and retracts the antenna in response to a variety of different events that require higher RSSI levels, giving mobile stations using the present invention method better performance.  
         [0070]    Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.