Abstract:
A system for archiving radio frequency (RF) power levels measured at distributed locations in a network ( 115 ) includes multiple RF power monitoring devices ( 105   a - 105   n ) and an archival server ( 120 ). Each of the power monitoring devices ( 105   a - 105   n ) measures an RF power level at a location of the device, and transmits one or more packets comprising the measured RF power level and a unique identifier associated with the device across a network ( 115 ). The archival server ( 120 ) receives the packets from each of the plurality of RF power monitoring devices ( 105   a - 105   n ), and stores the measured RF power levels and associated unique identifiers from the packets in a power history database.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to measurement and monitoring systems and, more particularly, to systems and methods for monitoring radio frequency power.  
         BACKGROUND OF THE INVENTION  
         [0002]    Cellular telephones are very rapidly growing in popularity. For example, there are now estimated to be about 100 million cell phone users in the United States alone. Furthermore, there are far more cell-phone users abroad and many indications that cell phones will entirely supplant “wired” phones in the coming years.  
           [0003]    Accompanying this growth, though, are increasing concerns regarding possible health issues involved with the use of cell phones. Many people are uncomfortable with the idea of placing radio transmitters very close to their brain. Some portion of the population also is uncomfortable with the idea of any artificial radio frequency (RF) transmissions in their immediate vicinity. Although there are no scientific indications to date that the RF emissions of cell phones (or other wireless devices) cause health problems, the American Cell-Phone Industry Group (CTIA) has recently decided that all new cell phones should be labeled with the maximum RF power that the phone can emit. This labeling is for the purpose of reassuring consumers that the cell phones they use are within the FCC-mandated power limits and, thus, are safe.  
           [0004]    With the increasing concerns regarding cell phone RF emissions there, therefore, exists a need for systems and methods that permit the monitoring of RF power levels within localized areas. Such localized monitoring would enable individuals or entities to assure the safety of specific areas from excessive RF power levels.  
         SUMMARY OF THE INVENTION  
         [0005]    Systems and methods consistent with the present invention address this and other needs by providing an easy to use, portable monitoring device that can indicate levels of RF power at localities of interest. Additionally, systems and methods consistent with the present invention provide a monitoring device that can measure RF power levels at specific locations and transmit the measured RF power levels to a server via a network, such as, for example, the Internet. The RF power levels received at the server may be archived as RF power histories for future retrieval.  
           [0006]    In accordance with the purpose of the invention as embodied and broadly described herein, a method of archiving radio frequency (RF) power profiles includes measuring an RF power level at an RF power monitoring device, transmitting the measured RF power level and a unique identifier associated with the RF power monitoring device to a measurement archival server across a network, and storing the measured RF power level and the unique identifier as a data record in the measurement archival server.  
           [0007]    In another implementation consistent with the present invention, a data structure encoded on a computer readable medium includes first data comprising a unique identifier associated with a radio frequency (RF) power monitoring device interconnected with a network, and second data comprising a RF power level measured at the RF power monitoring device.  
           [0008]    In a further implementation consistent with the present invention, a radio frequency power monitoring device includes a frequency selector configured to pass one or more radio frequency bands of a received radio frequency signal; a power estimator configured to estimate a power level of the received radio frequency signal; a memory; a processing unit configured to receive the power level from the power estimator, store the power level in the memory, and construct a record comprising the power level and a unique identifier associated with the radio frequency power monitoring device; and a network interface configured to transmit the record to a measurement collection server across a network.  
           [0009]    In an additional implementation consistent with the present invention, a method of monitoring radio frequency (RF) power at a hand-held RF power monitoring device includes receiving RF signals, frequency selecting the received RF signals, estimating a power level associated with the frequency selected RF signals, and activating at least one of a high, medium and low RF power level indicator based on the estimated power level. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the invention. In the drawings,  
         [0011]    [0011]FIG. 1 illustrates an exemplary network in which systems and methods, consistent with the present invention, may be implemented;  
         [0012]    [0012]FIG. 2 illustrates exemplary components of a RF power-monitoring device consistent with the present invention;  
         [0013]    [0013]FIG. 3 illustrates an exemplary configuration of a hand-held RF power-monitoring device consistent with the present invention;  
         [0014]    [0014]FIG. 4 illustrates another exemplary configuration of a hand-held RF power-monitoring device consistent with the present invention;  
         [0015]    [0015]FIG. 5 illustrates exemplary components of the detector and power estimator and RF intensity display of FIG. 2 consistent with the present invention;  
         [0016]    [0016]FIG. 6 illustrates an exemplary configuration of a wall-mounted RF power-monitoring device consistent with the present invention;  
         [0017]    [0017]FIG. 7 illustrates exemplary components of the RF power-monitoring device of FIG. 6 consistent with the present invention;  
         [0018]    [0018]FIG. 8 illustrates exemplary components of the measurement collection server of FIG. 1 consistent with the present invention;  
         [0019]    [0019]FIG. 9 illustrates an exemplary database stored in the measurement collection server of FIG. 8 consistent with the present invention;  
         [0020]    [0020]FIGS. 10A and 10B illustrate exemplary records of the database of FIG. 9 consistent with the present invention; and  
         [0021]    [0021]FIG. 11 is a flow chart that illustrates exemplary system processing consistent with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0022]    The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.  
         [0023]    Systems and methods consistent with the present invention provide mechanisms for measuring RF power levels at localities of interest. Additionally, systems and methods consistent with the present invention provide mechanisms for measuring RF power levels at specific locations and transmitting the measured RF power levels to a server via a network, such as, for example, the Internet. The RF power levels received at the server may be archived as RF power histories for future retrieval.  
       Exemplary Network  
       [0024]    [0024]FIG. 1 illustrates an exemplary network  100  in which systems and methods, consistent with the present invention, may operate to monitor RF power. Network  100  includes one or more RF sources  110   a - 110   n  and one or more RF power monitoring devices  105   a - 105   n . RF sources  110   a - 110   n  may include any type of RF emitter, including, for example, wireless telephony transmitters (e.g., wireless base stations and cellular phones). Network  100  may further include a sub-network  115  and a measurement collection server  120 . Sub-network  115  can include one or more networks of any type, including a local area network (LAN), metropolitan area network (MAN), wide area network (WAN), Internet, or Intranet. Measurement collection server  120  may store RF power measurements received from RF power monitoring devices  105   a - 105   n  via sub-network  115 . RF power monitoring devices  105   a - 105   n  may optionally interconnect with sub-network  115  via wired or optical connection links.  
       Exemplary RF Power Monitoring Device  
       [0025]    [0025]FIG. 2 illustrates an exemplary diagram, consistent with the present invention, of RF power-monitoring device  105 . Device  105  may include an antenna  205 , a frequency selector  210 , a detector and power estimator  215 , and a RF intensity display  220 . Antenna  205  may include a conventional antenna that facilitates the reception of RF signals. Frequency selector  210  may include circuitry for filtering the RF signals received at antenna  205  and passing one or more selected bands of frequencies to detector and power estimator  215 . For example, frequency selector  210  may be configured to pass frequencies in “cell phone” bands, such as 900 MHz or 1900 MHz bands. Additionally, frequency selector  210  may be configured to pass frequencies in the wireless LAN bands, such as, for example, the ISM band at 920 MHz or the Nil band at 5 GHz. Detector and power estimator  215  may include circuitry for providing an estimation of the RF power of signals received from frequency selector  210 . RF intensity display  220  may include circuitry and mechanisms for displaying the estimated RF power levels of received RF signals.  
       Exemplary Hand-Held RF Power Monitoring Device  
       [0026]    [0026]FIG. 3 illustrates an exemplary hand-held configuration of RF power monitoring device  105  consistent with the present invention. RF power monitoring device  105  may comprise a pen-shaped cylindrical housing that includes a protruding antenna  205 , RF intensity display  220  and an ON/OFF switch  305 . RF intensity display  220  may further include RF power level Light-Emitting Diodes (LEDs), such as “RED” LED  310 , “YELLOW” LED  315 , and “GREEN” LED  320 . “RED” LED  310  may indicate a high level of RF power received by RF power monitoring device  105 . “YELLOW” LED  315  may indicate a medium level of RF power received by RF power monitoring device  105 . “GREEN” LED  320  may indicate a low level of RF power received by RF power monitoring device  105 . Alternatively, RF intensity display  220  may include monochromatic LEDs or Liquid Crystal Displays (LCDs). ON/OFF switch  305  may selectively apply power to device  105  via an internal (e.g., battery) or external power supply.  
         [0027]    [0027]FIG. 4 illustrates another exemplary hand-held configuration of RF power monitoring device  105  consistent with the present invention. In this exemplary configuration, RF power monitoring device  105  may comprise a rectangular housing that includes an analog meter for the RF intensity display  220 .  
         [0028]    [0028]FIG. 5 illustrates an exemplary circuit diagram of the detector and power estimator  215  and RF intensity display  220  of FIG. 2. Detector and power estimator  215  may include diode D 1   505 , capacitor C 1   510  and resistors R 1   515 , R 2   520 , R 3   525 , R 4   530 , R 5   535  and R 6   540 . Diode D 1   505  rectifies RF signals received from antenna  205 . Capacitor C 1   510  and resistors R 1   515 , R 2   520  and R 3   525  form a low-pass filter, with the time constant of the filter set by capacitor C 1   510 . The value of C 1   510  can be selected such that (R 1 +R 2 +R 3 )*C 1 &gt;10 −3 . Resistors R 1   515 , R 2   520  and R 3   525  further form a resistive voltage divider for supplying voltages to RF intensity display  220 . The values of R 1   515 , R 2   520  and R 3   525  can be selected to set specific signal levels for “low,” “medium,” and “high” signal intensity. RF intensity display  220  may include LEDs D 2   545 , D 3   550  and D 4   555  that indicate RF signal intensity. Resistors R 4   530 , R 5   535  and R 6   540  can be selected to set the brilliance of LEDs D 2   545 , D 3   550  and D 4   555 , respectively.  
       Exemplary Wall-Mounted RF Power Monitoring Device  
       [0029]    [0029]FIG. 6 illustrates an exemplary wall-mounted configuration of RF power monitoring device  105  consistent with the present invention. RF power monitoring device  105  may include a rectangular-shaped housing that further includes a protruding antenna  205 , RF intensity display  220 , a loudspeaker  605  and an interface cable  610 . RF intensity display  220  may include a pixel-oriented display, such as, for example, a LCD or video display. RF intensity display  220  can draw continuous scrolling graphs of RF power levels received at antenna  205  as monitored over a time interval. For example, RF intensity display  220  may show the RF power as received within the past minute. The height of the displayed curve indicates the RF power as measured over a particular interval. RF intensity display  220 , thus, indicates recent historical RF power levels. Loudspeaker  605  may include conventional mechanisms for outputting an audio alarm signal when received RF power exceeds some specified maximum value. Interface cable  610  may connect RF power monitoring device  105  to network  115 .  
         [0030]    [0030]FIG. 7 illustrates an exemplary diagram, consistent with the present invention, of the RF power-monitoring device  105  shown in FIG. 6. RF power monitoring device  105  may include an antenna  205 , a frequency selector  210 , a detector and power estimator  215 , a processing unit  705 , a memory  710 , a network interface  715 , output device(s)  720 , input device(s)  725 , a Global Position System (GPS) receiver  730 , and a bus  735 . Antenna  205  may include a conventional antenna that facilitates the reception of RF signals. Frequency selector  210  may include circuitry for filtering the RF signals received at antenna  205  and passing selected bands of frequencies to detector and power estimator  215 . For example, frequency selector  210  may be configured to pass frequencies in “cell phone” bands, such as 900 MHz or 1900 MHz bands. Additionally, frequency selector  210  may be configured to pass frequencies in the wireless LAN bands, such as, for example, the ISM band at 920 MHz or the NIL band at 5 GHz. Detector and power estimator  215  may include circuitry for providing an estimation of the RF power of signals received from frequency selector  210 .  
         [0031]    Processing unit  705  may perform data processing functions for inputting, outputting, and processing of RF power measurement data received from detector and power estimator  215 . Memory  710  provides permanent, semi-permanent, or temporary working storage of RF power measurement data and instructions for use by processing unit  705  in performing processing functions. Memory  710  may include large-capacity storage devices, such as a magnetic and/or optical recording device. Network interface  715  may include conventional circuitry for interfacing RF power monitoring device  105  with an external network, such as sub-network  115 . Output device(s)  720  may include conventional mechanisms for outputting data in video, audio, and/or hard copy format. Output device(s)  720  may include, for example, RF intensity display  220  and loudspeaker  605 . Input device(s)  725  permit entry of data into RF power monitoring device  105  and may include a user interface (not shown). GPS receiver  730  may include conventional circuitry for receiving GPS signals and determining a geographic location of RF power monitoring device  105 . Bus  735  interconnects the various components of RF power monitoring device  105  to permit the components to communicate with one another.  
       Exemplary Measurement Collection Server  
       [0032]    [0032]FIG. 8 illustrates exemplary components of measurement collection server  120  consistent with the present invention. Measurement collection server  120  may include a processing unit  805 , a memory  810 , an input device  815 , an output device  820 , network interface(s)  825  and a bus  830 . Processing unit  805  may perform all data processing functions for inputting, outputting, and processing of data. Memory  810  may include Random Access Memory (RAM) that provides temporary working storage of data and instructions for use by processing unit  805  in performing processing functions. Memory  810  may additionally include Read Only Memory (ROM) that provides permanent or semi-permanent storage of data and instructions for use by processing unit  805 . Memory  810  can also include large-capacity storage devices, such as a magnetic and/or optical device.  
         [0033]    Input device  815  permits entry of data into measurement collection server  120  and may include a user interface (not shown). Output device  820  permits the output of data in video, audio, or hard copy format. Network interface(s)  825  interconnect measurement collection server  120  with network  115 . Bus  830  interconnects the various components of measurement collection server  120  to permit the components to communicate with one another.  
       Exemplary Measurement Collection Server Database  
       [0034]    [0034]FIG. 9 illustrates an exemplary database  900  that may be stored in memory  810  of measurement collection server  120 . Database  900  may include RF power history records  905  associated with RF power monitoring devices  105   a - 105   n  interconnected with sub-network  115 . Database  900  may further include RF power monitoring device identifier/location records  910  that map unique identifiers associated with each RF power monitoring device  105   a - 105   n  to a geographic location of each device  105   a - 105   n.    
         [0035]    [0035]FIG. 10A illustrates an exemplary record  1000  of RF power history records  905 . Record  1000  may include a device identifier  1005 , a time stamp  1010 , and a RF power level  1015 . Device identifier  1005  may include a unique identifier associated with the RF power-monitoring device  105   a - 105   n  that measured the RF power level  1015 . Device identifier  1005  may include a unique device serial number, a uniquely assigned numeric/alpha-numeric identifier, or a network address (e.g., an IP address) associated with the RF power-monitoring device  105   a - 110   n  that has sent an RF power level to measurement collection server  120 . Time stamp  1010  specifies a time that an RF power level was measured at RF power monitoring device  105   a - 110   n . RF power level  1015  indicates the RF power level measured at the RF power-monitoring device  105   a - 105   n  associated with IP address  1005  at the time specified by time stamp  1010 .  
         [0036]    [0036]FIG. 10B illustrates an exemplary record  1020  of device ID/location records  910 . Record  1020  may include the device identifier  1005  and a device location  1025 . The device identifier  1005  includes an identifier associated with the RF power monitoring device  105   a - 105   n  that has sent an RF power level to measurement collection server  120 . Device location  1030  includes location data associated with the device identified by device identifier  1005 . Device location  1030  may include location data derived from GPS signals received at RF power monitoring device  105   a - 105   n . Device location  1030  may further include any type of location data that identifies a geographic location of RF power monitoring device  105   a - 105   n.    
       Exemplary System Processing  
       [0037]    [0037]FIG. 11 is a flowchart that illustrates exemplary processing, consistent with the present invention, for measurement and transfer of RF power measurements from RF power monitoring device  105  to measurement collection server  120 . Processing may begin with RF power monitoring device  105  measuring an RF power level [step  1105 ]. RF power monitoring device  105  may then time stamp the RF power measurement [step  1110 ]. RF power monitoring device  105  may further store the RF power measurement and time stamp in memory  710  [step  1115 ]. RF power monitoring device  105  may then display the RF power measurement on the RF intensity display of output device(s)  720  [step  1120 ].  
         [0038]    RF power monitoring device  105  may, optionally, receive a GPS signal at GPS receiver  730  and determine a geographic location of the device in accordance with conventional techniques [step  1125 ]. RF power monitoring device  105  may then transmit the RF power measurement, the associated time stamp, the device  105 &#39;s device identifier  1005 , and, optionally, device  105 &#39;s determined device location  1025  to measurement collection server  120  via sub-network  115  [step  1130 ]. This information may be transmitted, for example, as one or more packets of data. Measurement collection server  120  may receive the transmitted information and store the RF power level measurement  1015 , time stamp  1010 , and device identifier  1005  as a record in power history records  905  of database  900 , and device identifier  1005  and device location  1025  as a record in device ID/location records  910  [step  1135 ]. Device location  1025  may include a location associated with device identifier  1005  that has been previously stored in server  120 . Steps  1105 - 1135  can be selectively repeated to create a RF power profile associated with a particular RF power-monitoring device  105  in database  900 . This RF power profile may be used, for example, by cellular service providers for cell planning or to provide evidence that the emitted RF power at designated localities does not exceed specified maximum values.  
       Conclusion  
       [0039]    As described above, systems and methods consistent with the present invention provide mechanisms for measuring RF power levels at localities of interest. Additionally, systems and methods consistent with the present invention provide mechanisms for transmitting the measured RF power levels to a server via a network where the power levels may be archived as RF power histories for future retrieval.  
         [0040]    The foregoing description of exemplary embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while certain components of the invention have been described as implemented in hardware and others in software, other configurations may be possible. Also, while series of steps have been described with regard to FIG. 11, the order of the steps is not critical. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used. The scope of the invention is defined by the following claims and their equivalents.