Abstract:
Reducing power consumption and interference in wireless communication is provided. For example, in one embodiment, a method is provided that listens for radio frequency (“RF”) activity on a receiver utilizing a first receiver antenna. When no RF activity is detected the receiver is switched “on” and a command is transmitted. If a reply to the transmission is not received the receiver is turned “off.” After an expiration of time, the receiver is again switched “on” and another command is transmitted on a second antenna coupled to the receiver. Thereafter, if a reply is not received the receiver is again turned “off.” Embodiments of the invention also include other methods, computer-readable mediums, apparatuses, and systems that contain features similar to the features in the above described method.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/971113, filed Sep. 10, 2007, which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention generally relate to security systems and more particularly, to methods, computer-readable mediums, apparatuses, and systems for reducing keypad power consumption. 
         [0004]    2. Description of the Related Art 
         [0005]    In a wireless security system, when the radio frequency (“RF”) signaling strength between a wireless transmitter and a wireless receiver is sufficient, the collision of messages between wireless components of the system is one of the most critical and limiting factors in the performance of the system. Collisions cause supervisory messages and sometimes alarm messages to be lost, cause a slow system response and practically limit the number of wireless components in a system. 
         [0006]    Simple wireless security systems, using transmitters in the sensors and a receiver at the main control panel cannot detect a collision. Consequently these systems transmit a message multiple times, thereby increasing bandwidth usage, increasing the probability of message corruption by a collision, decreasing battery life and decreasing system response time. 
         [0007]    Therefore, there is a great need in the art for a wireless security keypad having an improved battery life. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention generally relates to security systems and more particularly, to methods, computer-readable mediums, apparatuses, and systems for reducing keypad power consumption. 
         [0009]    For example, in one embodiment, the method uses an algorithm known as Listen Before Talk (“LBT”), which prevents the start of a transmission while some other component is already transmitting, thus preventing a collision of messages with the other transmitting component. This is also known as Collision Avoidance (“CA”). 
         [0010]    In various embodiments, an algorithm dynamically adjusts (i.e., increases or decreases) the emitted power level of the transmission based on the received signal strength (“RSSI”) and link quality measurement of the previous correct received message at the receiving end. An acknowledgement message contains an indication of the signal quality as received by the receiving end, by which indicated signal quality the transmitting end adjusts it&#39;s output power for the next transmission to occur. 
         [0011]    Other embodiments are also provided in which a computer-readable mediums, apparatuses, and a systems perform similar features recited by the above methods. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0013]      FIG. 1  depicts an embodiment of an exemplary security keypad in accordance with aspects of this disclosure. 
           [0014]      FIG. 2  depicts an embodiment of an exemplary method in accordance with aspects of this disclosure. 
           [0015]      FIG. 3  depicts an embodiment of another exemplary method in accordance with aspects of this disclosure. 
           [0016]      FIG. 4  depicts an embodiment of a transmission model in accordance with aspects of this disclosure. 
           [0017]      FIG. 5  depicts a high-level block diagram of a computer architecture in accordance with aspects of this disclosure. 
           [0018]    To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    In the following description, numerous specific details are set forth to provide a more thorough understanding of the invention. As will be apparent to those skilled in the art, however, various changes using different configurations may be made without departing from the scope of the invention. In other instances, well-known features have not been described in order to avoid obscuring the invention. Thus, the invention is not considered limited to the particular illustrative embodiments shown in the specification and all such alternate embodiments are intended to be included in the scope of this invention. For example, aspects disclosed herein are described as using transmission of “status request messages” for sending commands (e.g., key presses from the keypad to the panel). However, this disclosure is not limited to sending status request messages. Neither is the described method limited to keypads and IO devices. In various embodiments, the material disclosed herein can utilize sensors and/or other wireless components in the system. Further, when such a component has only a single antenna, rather than the keypad using two antenna&#39;s, various embodiments of the invention utilize antenna  1  (see  FIG. 4  and the description below). 
         [0020]      FIG. 1  depicts an embodiment of an exemplary security keypad system  100  in accordance with aspects of this disclosure. Security keypad system  100  includes a wireless keypad  102  and a control panel  108 . The wireless keypad  102  includes a liquid crystal display (“LCD”) (e.g., dual type information display)  104 ; and a user interface  106  (e.g., depicted as buttons for data input and/or response selection). Lead-line  110  demarcates a wireless communication path between keypad  102  and control panel  108 . 
         [0021]    A user is able to control a security system using the wireless keypad  102 . However, when the wireless keypad  102  is not in a fixed location or in proximity to a fixed location the user is prevented from accessing a feature on the wireless keypad (e.g., the user is prevented from arming the alarm system). For example, when the wireless keypad  102  is not secured to the keypad wall mount bracket  108 , the user will not be able to access the feature associated with arming the security system. The material disclosed herein reduced the number of retry attempts of a wireless transmission in order to preserve battery life and obtain a more reliable wireless communication. Instead of transmitting a message, a device (e.g., wireless keypad  102 ) listens to determine whether there are transmissions in progress by some other wireless component in the system. If another component is transmitting at that particular moment in time then the device will delay its own transmission until the other component is finished (which typically takes about a few milliseconds). 
         [0022]      FIG. 2  depicts an embodiment of an exemplary method  200  in accordance with aspects of this disclosure.  FIG. 4  depicts an exemplary application of the method  200  depicted in  FIG. 2  in accordance with aspects disclosed herein. Specifically,  FIG. 4  depicts an embodiment of a timeline  400  using the exemplary method depicted in  FIG. 2 .  FIG. 4  also includes a legend explaining aspects of the timeline  400 . For easier understanding, a reader is encouraged to simultaneously view  FIGS. 2 and 4 . 
         [0023]    Returning to  FIG. 2 , the method  200  begins at step  202  and proceeds to step  204 . At step  204 , the keypad  102 , using antenna  1   402 , listens for RF activity (see also keypad state  406  of  FIG. 4 ) from any other component (e.g., other keypad or sensor) (also referred to herein as “Listen Before Talk”). The keypad  102  periodically interrogates the panel  108  for a system state update of the panel  108  (i.e., to determine if the panel has changed state). Immediately after the keypad  102  determines that there is no RF activity, a timespan “t4” begins. After interrogation, the method  200  proceeds to step  206 . 
         [0024]    When no RF activity is detected, at step  206 , the keypad  102  transmits a “Request_for_Update” message to the panel  108  using antenna  1 . During transmission of the message, at step  206 , the transmission state of the keypad  102  is illustratively depicted in  FIG. 4  keypad state  408 ; and the transmission state of the panel  108  is depicted as panel state  410  (when the panel receives the “Request_for_Update” message). Thereafter, the method  200  proceeds to step  208 . 
         [0025]    At step  208 , the keypad  102  immediately switches its receiver “ON” to receive a reply message from the panel  108 . During step  208 , keypad state  414 , in  FIG. 4 , depicts the state of the keypad  102 . When the keypad receiver is turned “ON,” a timespan “t1” is initiated and begins a predetermined timespan for the keypad receiver to be turned “ON.” During a portion of timespan t 1 , there is a latency  412 , due to processing, in the panel  108 . After the latency  412 , the panel  108  transmits a reply message on the same antenna (e.g., panel antenna  1  (not shown)) used when the keypad&#39;s “Request_for_Update” message was received. The state of the panel  108  during transmission of the reply message is panel state  418 . At the expiration of a first timespan t 1  (depicted in  FIG. 4  as point “A”), the method  200  proceeds to step  210 . 
         [0026]    At step  210 , when no reply from the panel  108  has been received at point A, the keypad  102  times-out and switches the keypad receiver “OFF.” A timespan “t2” begins at about the same time as timespan t 1  with a duration less than the duration of the reply message (i.e., when the keypad receiver is turned ON) and ends prior to an initiation of a subsequent timespan also having a duration of t 1 . Thereafter, the method  200  proceeds to step  212 . 
         [0027]    The panel  108  transmits a reply multiple times (e.g., twice) using either antenna because the panel  108  doesn&#39;t know if the reply message was correctly received by the keypad  102 . The keypad only needs to listen for a reply until the correct reply is received, and doesn&#39;t need to retransmit to the panel  108 . As a result, power is saved at the keypad  102 . 
         [0028]    After timespan t 2  (i.e., at step  212 ), another timespan t 1  begins and the keypad  102  switches the keypad receiver ON again. Following the transmission of a first reply message by the panel  108 , panel  108  transmits a second reply using the panel&#39;s alternative antenna. Transmission of the second reply message begins shortly after the second timespan t 1  begins. 
         [0029]    At point B, when again no reply has been received from the panel  108 , the keypad  102  switches off its receiver and waits for the retry timeout t 4  period to elapse. After timeout t 4 , the keypad  102  transmits a second “Request_for_Update” message, now using its antenna 2   404 . In the full sequence of transmission of data between the keypad and the panel,  FIG. 400  illustratively depicts a failure to receive a reply for the first three occasions ( 414  at point A or B) and a success receiving a reply at the last occasion  416 . 
         [0030]    When a valid sync of the reply message has been detected (e.g. when message address of receiver and destination match), at point C, the keypad receiver is NOT switched OFF, but continues to receive the panel reply message. 
         [0031]    At point D, the entire panel reply message has been received. The keypad  102  receiver is switched off and a cyclic redundancy check is performed to validate and accept the message content of the message validates the reply. If no valid CRC was found, timeout t 3  eventually drops the attempt to receive the reply. The sequence will repeat every t 4  seconds. 
         [0032]    A practical value for timeout t 4  is 4 seconds, which implies that the panel will be able to inform the keypad about changes in the system state 2 seconds late on the average. 
         [0033]    In various embodiments, there are multiple keypads (e.g., up 4 wireless keypads) and multiple I/O modules (e.g., up to 4 wireless I/O modules) communicating in a system depicted in  FIGS. 2 and 4 . Taking into account that wireless outdoor sirens and beacons will be constructed around the mentioned I/O modules, start of sounding and/or flashing will be 4 seconds late at the most. 
         [0034]    Further, in various embodiments, the panel  108  changes antenna regularly, but never during reception of a request and subsequent transmission of a reply. 
         [0035]      FIG. 3  depicts an embodiment of an exemplary method  300  for dynamic transmission power optimization in accordance with aspects of this disclosure. More specifically, in method  300  the control radio panel module  108  dynamically controls the transmission power level of keypad  102  and I/O module (not shown). As explained in greater detail below, the control radio panel module  108  returns a single bit in a reply message, indicating whether the keypad  102  should increase or decrease the transmission power level of a next transmission. Herein, the transmission power level is expressed in dBm. Generally, dBm is used and defined herein as an abbreviation for the power ratio in decibel (dB) of the measured power referenced to one milliwatt (mW). 
         [0036]    The method  300  begins at step  302  when the keypad  102  is turned “on” and proceeds to step  304 . [ 0035 ] At step  304  the method  300  queries whether this is the first transmission of the keypad  102 . When the keypad  102  is turned “on” the keypad transmits a communications signal towards the control panel radio module  108 . If, at step  302 , it is the first time that the keypad  102  has been turned “ON” then there are no previous transmissions. At the first transmission, when the keypad  102  (or some other component in the system) is turned ON there is no history as to how loud (i.e., how strong) the keypad  102  (or other component) should transmit. If this is the first transmission by the keypad  102  (or other component) then the query at step  304  is answered affirmatively and the method  300  proceeds to step  306 . 
         [0037]    At step  306 , the transmission level is set to 0 dBm (a factory setting). There is only one first transmission from power up. The transmission from power up will be transmitted at a level of 0 dBm and messages transmitted at this transmission level may fail (it may not be loud enough for the control panel radio module  108  to pick up that message and send an acknowledgement). Because of the low transmission level, the keypad  102  will not get an acknowledgement from the control panel radio module  108  on first power up. After step  306 , the method  300  proceeds to and ends at step  322  where the transmission level is set for the next transmission. 
         [0038]    If however, the query at step  304  is answered negatively, the method  300  proceeds to step  308 . The query at step  304  is answered negatively when the keypad  102  (or other system component) had been previously powered up (i.e., sent a transmission). 
         [0039]    At step  308 , the method  300  queries whether the signal transmitted (e.g., by the keypad  102 ) is a retry attempt. If the query is answered affirmatively, the method proceeds to step  316 . 
         [0040]    At step  316  the transmission level of the signal transmitted by the keypad  102  is increased to the maximum transmission level (illustratively the maximum transmission level is described and depicted as +12 dBm) of the device  102 . Thereafter the method  300  proceeds to and ends at step  322 . 
         [0041]    Returning to step  308 . If a negative determination is made at step  308  (i.e., that the transmission attempt is not a retry attempt), the method  300  proceeds to step  310 . 
         [0042]    At step  310 , the method  300  queries whether the signal strength indication flag as received from the control panel radio module  108  in the previous reply message of the panel indicates that the power level of the transmission signal transmitted by the keypad  102  should be increased. If the query at step  310  is answered affirmatively, the method  300  proceeds to step  314 . If however, the query at step  310  is answered negatively, the method  300  proceeds to step  312 . 
         [0043]    Returning to step  310  the method  300  proceeds to step  314  when an affirmative determination is made at step  314 . At step  314 , the method  300  queries whether the transmission level of the keypad  102  is already at its maximum transmission level. For illustrative purposes only, step  314  is described and depicted as having a maximum value of ±12 dBm. If the keypad is already at its maximum transmission level then the query at step  314  is answered affirmatively and proceeds to step  322 . 
         [0044]    If however, the query at step  314  is answered negatively, the method  300  proceeds to step  320 . At step  320  the transmission level of the keypad  102  is given an incremental increase (e.g., an increase of about +0.5 dBm). Thereafter, the method  300  proceeds to step  322 . 
         [0045]    Returning to step  310 . If a negative determination is made at step  310  (i.e., that the single bit in the reply message from the control panel radio module  108  did not indicate that the transmit level should be increased), the method  300  proceeds to step  312 . Step  312  queries whether the transmission level of the keypad  102  is at its minimum transmission level (e.g., −20 dBm). Illustratively  FIG. 3  depicts the minimum transmission level of the keypad  102  as −20 dBm. However, that depiction is for illustrative purposes only and not intended in any way to limit the scope of the invention. 
         [0046]    If the query at step  312  is answered affirmatively then the transmission level cannot be reduced further. As such, upon an affirmative determination at step  312 , the method  300  proceeds to step  322 . 
         [0047]    If however, the query at step  312  is answered negatively then the transmission level of the keypad  102  is not at its minimum transmission level and can be lowered. As such, upon a negative determination at step  312 , the method  300  proceeds to step  318 . 
         [0048]    At step  318  the transmission level of the keypad  102  is given an incremental decrease (e.g., an incremental decrease of about 0.5 dBm). Thereafter, the method  300  proceeds to and ends at step  322 . 
         [0049]      FIG. 5  depicts a high level block diagram of an embodiment of a controller  500 , as part of electronic circuitry, suitable for use in performing the methods and model disclosed above and depicted in  FIGS. 2 ,  3 , and  4 . The controller  500  of  FIG. 5  comprises a processor  506  as well as a memory  508  for storing control programs  510  and the like. In addition, the memory  508  can also store the transmission power level management module (as explained above in regarding  FIG. 3 ) and/or messaging model module (as explained above regarding  FIGS. 2 and 4 . The processor  506  cooperates with conventional support circuitry  404  such as power supplies, clock circuits, cache memory and the like as well as circuits that assist in executing the software routines stored in the memory  508 . As such, it is contemplated that some of the process steps discussed herein as software processes may be implemented within hardware, for example, as circuitry that cooperates with the processor  506  to perform various steps. The controller  500  also contains input-output circuitry  502  that forms an interface between the various functional elements communicating with the controller  500 . 
         [0050]    Although the controller  500  of  FIG. 5  is depicted as a general-purpose computer that is programmed to perform various control functions in accordance with the present invention, the invention can be implemented in hardware, for example, as an application specified integrated circuit (ASIC). As such, the process steps described herein are intended to be broadly interpreted as being equivalently performed by software, hardware, or a combination thereof. 
         [0051]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.