Patent Publication Number: US-2017350834-A1

Title: Apparatus and method for detecting concealed explosives

Description:
BACKGROUND 
     Field of the Invention 
     The present invention is generally related to the detection of explosives and is more specifically related to the detection of concealed explosives in electronic devices using nuclear quadrupole resonance (NQR) spectroscopy. 
     Related Art 
     Hidden explosives pose a significant and well-documented threat to public safety. Mass transit systems, particularly commercial airliners, have been a perpetual target for acts of terrorism. Over the last three decades, the extent of passenger and luggage screening has drastically increased in response to atrocities like the bombing of Pan Am Flight 103 and the September 11 attacks. But while some of the more recent attempts to smuggle explosives onboard aircrafts have been crude, security experts anticipate that the next iteration of improvised explosive devices to emerge will be much more sophisticated and effective as a result. 
     In particular, security experts are warning of efforts to convert common models of portable consumer electronic devices (e.g., smartphones, tablet PCs) into stealth explosive contraptions. In this manner, explosives materials are cleverly disguised to successfully evade conventional detection methods. X-Rays, for example, do not provide sufficient spatial resolution to enable a proper inspection of the internal composition of electronic devices. In particular, explosive materials that have been arranged in a sheet or planar configuration inside, for example, an iPhone® or an iPad® will generally appear innocuous in an X-Ray scan. Explosive trace detectors (ETDs), meanwhile, rely on the presence of particulates. As such, cleaning the exterior surface of an electronic device after modifying the electronic device to include explosive materials will effectively frustrate the ability of an ETD to accurately identify the electronic device as a threat. Finally, canine detection units are expensive to maintain and operate. In practice, bomb sniffing dogs require frequent breaks and can exacerbate congestion at crowded security checkpoints. In addition, it is possible for concealed explosive materials to be hermetically sealed within a modified electronic device, which would render common scent or vapor detection methods (e.g., bomb sniffing dogs, explosive vapor detector) virtually useless. 
     SUMMARY 
     To effectively and efficiently detect concealed explosives, various embodiments of the apparatus and method described herein are directed toward the use of nuclear quadrupole resonance (NQR) spectroscopy to detect the presence of one or more types of solid explosive compounds, substances, or materials. In various embodiments, NQR spectroscopy is used to detect explosives that have been deliberately embedded, camouflaged, or otherwise concealed within an electronic device. In various embodiments, NQR spectroscopy is used to detect various types of solid explosives (e.g., plastic explosives) concealed within personal or portable electronic devices, including but not limited to smartphones, tablet PCs, laptops, and headsets. 
     NQR is a chemical analysis technique that exploits the electric quadrupole moment possessed by certain atomic nuclei (e.g.,  14 N,  17 O,  35 Cl, and  63 Cu). An electric quadrupole moment arises from the presence of two adjacent electric dipoles (i.e., opposite charges separated by a short distance) in an atomic nucleus. Otherwise stated, an electric quadrupole moment is caused by an asymmetry in the distribution of the positive electric charge within the nucleus, which is typically the case for any atomic nucleus described as either a prolate (i.e., “stretched”) or oblate (i.e., “squashed”) spheroid. The interaction between the intrinsic electric quadrupole moment and an electric field gradient (EFG) within the nucleus generates distinct energy states. As such, the primary goal of NQR spectroscopy is to determine the resonant or NQR frequency at which the transition between these distinct energy states occur and then relate this property to a specific material, substance, or compound. Since the EFG surrounding a nucleus in a given substance is determined primarily by the valence electrons engaged in the formation of chemical bonds with adjacent nuclei, different substances will exhibit distinct resonant or NQR frequencies. The NQR frequency of a substance depends on both the nature of each atom comprising the substance and on the overall chemical environment (i.e., the other atoms in the substance). This renders NQR spectroscopy especially sensitive to the chemistry or composition of each substance. When a substance is irradiated or interrogated with radio frequency (RF) electromagnetic radiation, energy will be absorbed by each nucleus within the substance when the frequency of the interrogation electromagnetic radiation coincides with the specific NQR frequency for that substance. The absorption of energy at the specific NQR frequency for the substance causes a transition to a higher energy state followed by an emission of energy (i.e., feedback electromagnetic radiation) during a subsequent return to a lower energy state. This emission of energy is at the same frequency as the NQR frequency specific to that substance. As such, the NQR frequency of the feedback electromagnetic radiation emitted by a substance can act as a chemical signature for that substance. With respect to explosives, the NQR frequency of one or more chemical components of an explosive substance, material, or compound can be used to identify the presence of the explosive regardless of efforts to physically conceal the explosives, such as within an electronic device. 
     In the various embodiments described herein, explosives concealed within electronic devices are detected using a NQR scanner. In various embodiments, the NQR scanner is configured to detect one or more different types of solid explosive materials, substances, or compounds. In fact, in various embodiments, the NQR scanner is capable of detecting any desired, required, or appropriate number of different explosive materials, substances, or compounds, including but not limited to a variety of plastic explosives. In some exemplary embodiments, the NQR scanner is a tabletop device that includes a detection cavity. In various embodiments, the detection cavity comprises an opening, a drawer, a conveyor system, or any other appropriate receptacle, medium, and/or mechanism to hold, enclose, or otherwise contain a target object such as an electronic device during the NQR scanning process. Electronic devices such as smartphones, tablet PCs, and laptops generally include a number of conductive surfaces. Exposing a conductive surface to interrogation electromagnetic radiation from an undesirable or unsuitable angle (e.g., substantially orthogonal to the conductive surface) tends to induce an electric current across the conductive surface. An electric current across any of the conductive surfaces in an electronic device could generate false signals that mask the feedback electromagnetic radiation from explosive materials, substances, or compounds that may be hidden within the electronic device. Thus, in certain exemplary embodiments, the detection cavity is further configured to orient the conductive surfaces of the electronic device at a desirable or suitable angle with respect to the direction of the interrogation electromagnetic radiation. 
     In various embodiments, once inserted inside the detection cavity, the target object is subject to a sequence of specifically timed interrogation electromagnetic radiation. That is, in various embodiments, the NQR scanner tests the target object for the presence of various chemical components of explosive materials, substances, or compounds by irradiating the electronic device with certain frequencies of interrogation electromagnetic radiation and measuring the frequencies of the feedback electromagnetic radiation that is emitted in response. For example, in some embodiments, the NQR scanner is configured to detect the NQR frequency that uniquely identifies the primary explosive compound(s) found in certain plastic explosives. 
     Furthermore, in various embodiments, the NQR scanner is configured to detect interference and noise signals, including but not limited to signals from intentional jamming, the environment, and the target object itself. In some embodiments where the target object is an electronic device such as a smartphone or a tablet PC, powering on the device can generate unwanted noise signals that mask feedback electromagnetic radiation from explosive materials, substances, or compounds potentially hidden within the electronic device. In certain exemplary embodiments, the NQR scanner is configured to mitigate the effects of various interference and noise signals. As one example, in certain exemplary embodiments, the NQR scanner includes one or more shielding mechanisms to block, suppress, or otherwise minimize interference and noise signals from the surrounding environment. In various embodiments, the NQR scanner can be additionally or alternately configured to report unusually high levels of interference or noise signals. Additionally, in some exemplary embodiments, the NQR scanner provides a simple user interface. For example, in some embodiments, the NQR scanner is configured to provide a visual and/or audio alarm to indicate when the scanner encounters one or more different types of explosive materials. 
     Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and operation of the present invention will be understood from a review of the following detailed description and the accompanying drawings in which like reference numerals refer to like parts and in which: 
         FIG. 1  illustrates an embodiment of an apparatus used for detecting concealed explosives; 
         FIG. 2  illustrates an embodiment of an apparatus used for detecting concealed explosives; 
         FIG. 3A  illustrates an embodiment of an apparatus used for detecting concealed explosives; 
         FIG. 3B  illustrates an embodiment of an apparatus used for detecting concealed explosives; 
         FIGS. 4A-4C  illustrate embodiments of a process for detecting concealed explosives; and 
         FIG. 5  illustrates a wired or wireless processor enabled device that may be used in connection with the various embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments disclosed herein provide for an apparatus and a method of detecting concealed explosives. For example, in various embodiments, a NQR scanner is used to detect the presence of explosives hidden inside electronic devices such as smartphones and tablet PCs. After reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example only, and not limitation. As such, this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention as set forth in the appended claims. 
       FIG. 1  illustrates an embodiment of Apparatus  100  used for detecting concealed explosives. In one exemplary embodiment, Apparatus  100  is a table top device that can be installed at a security checkpoint at an airport, a VIP event, or any other vulnerable area or facility. In various embodiments, Apparatus  100  comprises a NQR scanner. In various embodiments, Apparatus  100  includes an antenna (e.g., solenoid antenna) that generates interrogation electromagnetic radiation. In various embodiments, the interrogation electromagnetic radiation generated by the antenna are directed toward a target object such as an electronic device (e.g., smartphone, tablet PC). As described earlier, irradiating the target object with an interrogation electromagnetic radiation can cause the target object to emit feedback electromagnetic radiation. In various embodiments, the antenna is configured to generate a sequence of interrogation electromagnetic radiation at varying frequencies. Thus, in various embodiments, the target object is exposed to interrogation electromagnetic radiation at different frequencies. As described earlier, different chemical materials, compounds, or substances will absorb then emit electromagnetic radiation at individually unique NQR frequencies. The NQR frequency of a chemical material, compound, or substance thereby acts as a distinct chemical signature for that chemical material, compound, or substance. Thus, in various embodiments, Apparatus  100  is configured to irradiate the target object with interrogation electromagnetic radiation at frequencies corresponding to the NQR frequencies of the chemical components of one or more explosive materials, substances, or compounds, and to detect feedback electromagnetic radiation at those same frequencies. In various embodiments, Apparatus  100  further includes one or more sensors to detect, read, and/or measure the feedback electromagnetic radiation from the target object. 
     In various embodiments, Apparatus  100  is configured to identify potential explosive substances, materials, or compounds present in the target object based on the frequency of the feedback electromagnetic radiation. For instance, in various embodiments, the frequency of the feedback electromagnetic radiation from the target object is compared to or matched against the NQR frequencies associated with the various chemical components of one or more types of explosives. That is, since most explosive substances, materials, and compounds include a plurality of separate chemical components, in various embodiments, Apparatus  100  is configured to detect the presence of some or all of the chemical components in order to identity explosives that may have been hidden within the target object. For example, plastic Explosive X may contain Compound A as the primary explosive component, Compound B as a plasticizer, Compound C as a binder, and Compound D as the process oil. Thus, in one embodiment, to detect the presence of Explosive X, Apparatus  100  is configured to detect feedback electromagnetic radiation from the target object with a NQR frequency that uniquely identifies Compound A. In other embodiments, Apparatus  100  is configured to detect the presence of a predetermined and/or optimal number of chemical components that make up various explosive materials, compounds, or substances. It is to be understood that in various embodiments, Apparatus  100  is configured to perform separate and sequential tests or scans for each type of explosive material, compound, or substance. For example, Apparatus  100  is configured to detect different plastic explosives (e.g., Explosives X and Y) separately. 
     In some embodiments, the target device is irradiated with multiple rounds of interrogation electromagnetic radiation for each explosive in order to enhance the ratio of feedback electromagnetic radiation to any interference and/or noise signals. However, at least in some embodiments, Apparatus  100  is able interleave some or all of the detection process for different explosive compounds, materials, or substances, which optimizes the overall scan or detection time. For example, in some embodiments, Apparatus  100  is configured to intersperse multiple scans for Explosive X (e.g., irradiate the target object with interrogation electromagnetic radiation for Explosive X and detect feedback electromagnetic radiation) with one or more scans for Explosive Y. 
     In various embodiments, the overall detection time (i.e., NQR scan time) typically varies depending on the type(s) of explosive(s), since the nature of the NQR response is unique to each type of explosive material, substance, or compound. In some embodiments, the detection or scan time can be directly proportional to a total number of the different types of explosives that Apparatus  100  is required to detect. Furthermore, in various embodiments, both the overall scan or detection time and the confidence level associated with the detection results are directly proportional to the number of chemical components that Apparatus  100  is required to test with respect each explosive material, compound, or substance. In various embodiments, Apparatus  100  is generally able to complete one detection cycle or one full scan of a target object such as a smartphone or tablet PC within 2 to 10 seconds. Returning to the example with Explosives X and Y, in some embodiments, Apparatus  100  can additionally test for the presence of secondary components such as a plasticizer, binder, and/or process oil, in order to confirm or otherwise increase the certainty of the detection result. However, in some embodiments, Apparatus  100  can be configured to omit or bypass tests for certain chemical components, such as common or generic binders or plasticizers, in order to minimize the amount of time required to yield the detection result. In various embodiments, Apparatus  100  can be configured to test for an optimal number of chemical components depending on, for example, the compositions of the different explosive substances, materials, or compounds that Apparatus  100  is configured to detect for. Explosive Y, for example, is another type of plastic explosives and it contains the same explosive component, Compound A, as Explosive X. However, in addition to Compound A, Explosive Y also contains a different explosive component, Compound E. Thus, in some embodiments, in order to identify Explosive Y and to distinguish it from Explosive X, Apparatus  100  can be configured to test for Compound A and Compound B when detecting Explosive X, and to test for Compound A and Compound E when detecting Explosive Y. 
     In various embodiments, the amount of time the target object must be exposed to the interrogation electromagnetic radiation is inversely proportional to the size of the explosive material, compound, or substance. That is, in various embodiments, larger target objects require relatively shorter periods of irradiation before emitting sufficient feedback electromagnetic radiation to be read, measured, or detected by Apparatus  100 . In various embodiments, Apparatus  100  is configured to irradiate the target object with a sequence of interrogation electromagnetic radiation at different or varying frequency. In certain exemplary embodiments, Apparatus  100  is configured to irradiate the target object with interrogation electromagnetic radiation for an optimal duration of time for each frequency in the sequence. In various embodiments, the optimal irradiation duration is determined based on an amount of irradiation time required to detect a certain minimum threat level (e.g., the least amount of explosives needed to cause harm or damage). In various embodiments, the optimal irradiation duration is further determined based on a Receiver Operational Characteristic (ROC) curve. In various embodiments, the ROC curve describes the relationship between the probability of detection and the false alarm rate. 
     As shown in  FIG. 1 , Apparatus  100  includes a Detection Cavity  110 . In various embodiments, the Detection Cavity  110  comprises an opening, a drawer, a conveyor system, or any other appropriate receptacle, medium, and/or mechanism to hold, enclose, or otherwise contain the target object. In various embodiments, Apparatus  100  irradiates the target object inserted or placed in Detection Cavity  110  with interrogation electromagnetic radiation at varying frequencies. Furthermore, in various embodiments, Apparatus  100  comprises sensors that detect, read and/or measure feedback electromagnetic radiation from the target object inserted or placed in Detection Cavity  110 . In certain exemplary embodiments, Detection Cavity  110  is configured to orient the target object in a position that minimizes the profile of the target object or its angle with respect to the antenna and to the interrogation electromagnetic radiation. In particular, where the target object is an electronic device such as a smartphone or tablet PC, conductive surfaces tend to be aligned with the exterior surface of the electronic device. Thus, in various embodiments where the target object is positioned substantially parallel to the antenna, its conductive surfaces also remain substantially parallel to the interrogation electromagnetic radiation generated by the antenna.  FIG. 2  depicts a Target Object  120 , a smartphone in this case, being inserted into Detection Cavity  110  of Apparatus  100  in the manner described (i.e., substantially parallel to the antenna). In some embodiments, Target Object  120  is oriented in at less than a 20-degree angle relative to the antenna and to the interrogation electromagnetic radiation. In various embodiments, positioning the conductive surfaces substantially parallel (e.g., less than 20 degrees) to the interrogation electromagnetic radiation avoids or minimizes electric currents that can be induced across the conductive surfaces by orthogonally directed electromagnetic radiation. Advantageously, eliminating induced currents will generally also eliminate the concomitant noise signals, which can mask the actual feedback electromagnetic radiation from explosives hidden within Target Object  120 . 
     In various exemplary embodiments, Apparatus  100  is configured to detect explosives that have been concealed within an electronic device such as a smartphone or a tablet PC. In some embodiments, Apparatus  100  is configured to operate (i.e., perform NQR scans) on the electronic device when the electronic device has been powered off. When powered on, an electronic device such as a smartphone or tablet PC tends to generate undesirable noise signals that mask or otherwise interfere with the feedback electromagnetic radiation from explosives potentially hidden within the electronic device. Noise and other types of interference signals described in more detail below generally compromises the accuracy and reliability of scans performed by Apparatus  100  (e.g., increased rates of false positives and/or false negatives). However, in certain situations, it may be desirable, necessary, and/or appropriate to test an electronic device without having to power the device off first. Thus, in some embodiments, Apparatus  100  is configured to suppress signals that can come from an electronic device that is left on during the NQR scanning process. Alternately or in addition, in various embodiments, Apparatus  100  is configured to detect the feedback electromagnetic radiation within the noise signals generated by the electronic device. 
     In various embodiments, Apparatus  100  is additionally configured to measure the level of interference signals. For example, in some instances, Apparatus  100  may be subject to intentional jamming signals and/or interference signals from the surrounding environment. In certain exemplary embodiments, Apparatus  100  is configured to generate audio and/or visual alarms or alerts when it detects an unusual (e.g., greater than a certain threshold) level of interference signals. For example, in some embodiments, Apparatus  100  can indicate via a visual and/or audio output that an accurate or reliable scan cannot be performed as a result of interference signals. 
     As described earlier, some explosive substances, materials, or compounds (e.g., Explosives X and Y) comprise multiple chemical components. As such, some explosive substances feature feedback electromagnetic radiation at multiple resonant frequencies. Thus, in some embodiments, Apparatus  100  can be configured to irradiate the target object with additional frequencies of interrogation electromagnetic radiation in the event that Apparatus  100  detects excessive level(s) (e.g., greater than predetermined threshold) of noise and/or interference signals. For example, in one embodiment, Apparatus  100  can be configured to test the target object for Compound A of Explosive X. Suppose that Apparatus  100  detects an excessive amount of concomitant noise and/or interference signals. Under such circumstances, in some embodiments, Apparatus  100  can additionally test the target object for Compound B, C, and/or D of Explosive X in order to enhance the accuracy or confidence level associated with the detection results. 
     Although not shown in  FIG. 1 , in certain exemplary embodiments, Apparatus  100  can further comprise one or more shielding mechanisms to block interference signals from the surrounding environment. In various embodiments, some or all components of Apparatus  100  can be isolated from external interference signals using passive shielding. For example, in some embodiments, Detection Cavity  110  can be enclosed in conductive material (e.g., a Faraday Cage). Alternately, in some embodiments, Detection Cavity  110  can comprise a shielded “can” or “quiet tunnel” with an open top. The dimensions (i.e., length, width, and height) of the can or tunnel affect the propagation of interference signals on the inside of the can or tunnel. As such, in various embodiments, Apparatus  100  includes a shielded can or quiet tunnel with dimensions that optimize the deterrence or suppression of interference signals from the surrounding environment. 
       FIG. 3A  and  FIG. 3B  illustrates an embodiment of Apparatus  300  used for detecting concealed explosives. In various embodiments, Apparatus  300  is similar to Apparatus  100  described with respect to  FIG. 1 . However, in various embodiments, Apparatus  300  provides a different type or form of detection cavity. As depicted in  FIG. 3A and 3B , Apparatus  300  includes Detection Cavity  310 , which is shown as a drawer. In various embodiments, a target object is placed inside the drawer (i.e., Detection Cavity  310 ), which can then be slide shut.  FIG. 3A  shows Apparatus  300  with Detection Cavity  310  in a shut position while  FIG. 3B  shows Apparatus  300  with Detection Cavity  310  in an open and pulled out position. 
     Alternately, instead of the drawer depicted in  FIG. 3A and 3B , in other embodiments, Detection Cavity  310  can comprise a pass through tray and/or a conveyor system. In those embodiments, the sensors in Apparatus  300  are positioned or spaced based on the timing of the target object&#39;s passage through Detection Cavity  310 . That is, in various embodiments, the sensors to detect, read, or measure feedback electromagnetic radiation from the target object are positioned a sufficient distance from the antenna generating the interrogation electromagnetic radiation such that the target object can be irradiated for an adequate length of time before the sensors attempts to detect, read, or measure the feedback electromagnetic radiation. 
       FIG. 4A  illustrates an embodiment of a Process  400  for detecting explosives concealed within an electronic device. In various embodiments, Process  400  can be performed using Apparatus  100  described with respect to  FIG. 1 , or Apparatus  300  described with respect to  FIG. 3A and 3B . At  402 , the electronic device is inserted or placed in the detection cavity of the apparatus. At  404 , an indication is received to commence the NQR scan. For example, in some embodiments, an operator (e.g., a TSA agent) can press an “INSPECT” or “SCAN” button on the apparatus. As another example, in some embodiments, the apparatus can provide a touch screen, in which case the NQR scan can be initiated using one or more graphic user interface (GUI) control components displayed on the touch screen. Alternately, in some embodiments, the NQR scan is triggered by the insertion or placement of the electronic device inside the detection cavity. As such, in various embodiments, the NQR scan can be initiated with or without explicit manual input. At  406 , the apparatus auto-tunes the frequency of the interrogation electromagnetic radiation. In various embodiments, the interrogation electromagnetic radiation is auto-tuned to the NQR frequency that corresponds to a chemical component of a certain explosive material, substance, or compound (e.g., Compound A, B, C, or D in Explosive X). In various embodiments, the apparatus is configured to expose the electronic device to a sequence of interrogation electromagnetic radiation at different frequencies, corresponding to different chemical components and/or explosives. As such, in various embodiments, the apparatus auto-tunes such that the antenna generates interrogation electromagnetic radiation at the appropriate frequencies. 
     At  408 , interference and noise signals are detected. In various embodiments, interference and noise signals can originate from a variety of sources, including but not limited to the environment, the electronic device itself, and intentional jamming. At  410 , an offset frequency is determined. In various embodiments, the offset frequency is determined based at least in part on the interference and noise signals detected at  408 . For example, in some embodiments, the offset frequency accounts for the noise signals generated by the presence of the electronic device. In particular, in the event that the electronic device is to remain powered on during the NQR scan, the electronic device can generate undesirable noise signals that mask or otherwise interfere with feedback electromagnetic radiation from explosive materials. At  412 , the frequency of the feedback electromagnetic radiation that the apparatus is configured to detect is adjusted based on the offset frequency. At  414 , the electronic device is irradiated with interrogation electromagnetic radiation at a frequency that is specific to a particular chemical component. In various embodiments, the chemical component is one of a plurality of chemical components comprising an explosive material, substance, or compound. As such, in some embodiments, presence of one or all of the chemical components of an explosive can indicate the presence of the explosive within the target object. At  416 , the feedback electromagnetic radiation is measured and processed. In various embodiments, processing includes but is not limited to noise suppression, filtering, signal addition, and elimination of signal bursts. At  418 , steps  404 - 416  are repeated for a desired, required, or appropriate number of chemical components and/or explosive substances, materials, or compounds. Finally, at  420 , the results of the NQR scan are reported. For example, in some embodiments, the apparatus can provide an audio and/or visual alarm indicating that an explosive material, substance, or compound has been detected within the electronic device. In addition, in various embodiments, the apparatus is able to indicate, such as via the touch screen, the type(s) of explosive(s) detected. 
     Although Process  400  illustrated in  FIG. 4A  is described to include steps  402 - 420 , a person of ordinary skill in the art can appreciate that some steps, such as step  404 , can be fully or partially omitted. Furthermore, other than the sequence or order shown in  FIG. 4A , it is to be understood that steps  402 - 420  of Process  400  can be performed in any appropriate order or sequence. 
     For example, in  FIG. 4B , step  408  for detecting interference signals and noise signals takes place between steps  412  and  414 . In the embodiment shown in  FIG. 4B , the offset frequency is not determined based at least in part on the interference and noise signals detected in step  408 . 
     Similarly, in  FIG. 4C , step  408  for detecting interference signals and noise signals takes place between steps  414  and  416 . Additionally, in the embodiment shown in  FIG. 4C , the offset frequency is not determined based at least in part on the interference and noise signals detected in step  408 . 
       FIG. 5  is a block diagram illustrating an embodiment of a wired or wireless System  550  that may be used in connection with various embodiments described herein. For example the System  550  may be used to implement various controller modules comprising Apparatus  100  described with respect to  FIG. 1 . The system  550  can be a conventional personal computer, computer server, personal digital assistant, smart phone, tablet computer, or any other processor enabled device that is capable of wired or wireless data communication. Other computer systems and/or architectures may be also used, as will be clear to those skilled in the art. 
     System  550  preferably includes one or more processors, such as processor  560 . Additional processors may be provided, such as an auxiliary processor to manage input/output, an auxiliary processor to perform floating point mathematical operations, a special-purpose microprocessor having an architecture suitable for fast execution of signal processing algorithms (e.g., digital signal processor), a slave processor subordinate to the main processing system (e.g., back-end processor), an additional microprocessor or controller for dual or multiple processor systems, or a coprocessor. Such auxiliary processors may be discrete processors or may be integrated with the processor  560 . 
     The processor  560  is preferably connected to a communication bus  555 . The communication bus  555  may include a data channel for facilitating information transfer between storage and other peripheral components of the system  550 . The communication bus  555  further may provide a set of signals used for communication with the processor  560 , including a data bus, address bus, and control bus (not shown). The communication bus  555  may comprise any standard or non-standard bus architecture such as, for example, bus architectures compliant with industry standard architecture (“ISA”), extended industry standard architecture (“EISA”), Micro Channel Architecture (“MCA”), peripheral component interconnect (“PCI”) local bus, or standards promulgated by the Institute of Electrical and Electronics Engineers (“IEEE”) including IEEE 488 general-purpose interface bus (“GPIB”), IEEE 696/S-100, and the like. 
     System  550  preferably includes a main memory  565  and may also include a secondary memory  570 . The main memory  565  provides storage of instructions and data for programs executing on the processor  560 . The main memory  565  is typically semiconductor-based memory such as dynamic random access memory (“DRAM”) and/or static random access memory (“SRAM”). Other semiconductor-based memory types include, for example, synchronous dynamic random access memory (“SDRAM”), Rambus dynamic random access memory (“RDRAM”), ferroelectric random access memory (“FRAM”), and the like, including read only memory (“ROM”). 
     The secondary memory  570  may optionally include a internal memory  575  and/or a removable medium  580 , for example a floppy disk drive, a magnetic tape drive, a compact disc (“CD”) drive, a digital versatile disc (“DVD”) drive, etc. The removable medium  580  is read from and/or written to in a well-known manner. Removable storage medium  580  may be, for example, a floppy disk, magnetic tape, CD, DVD, SD card, etc. 
     The removable storage medium  580  is a non-transitory computer readable medium having stored thereon computer executable code (i.e., software) and/or data. The computer software or data stored on the removable storage medium  580  is read into the system  550  for execution by the processor  560 . 
     In alternative embodiments, secondary memory  570  may include other similar means for allowing computer programs or other data or instructions to be loaded into the system  550 . Such means may include, for example, an external storage medium  595  and an interface  570 . Examples of external storage medium  595  may include an external hard disk drive or an external optical drive, or and external magneto-optical drive. 
     Other examples of secondary memory  570  may include semiconductor-based memory such as programmable read-only memory (“PROM”), erasable programmable read-only memory (“EPROM”), electrically erasable read-only memory (“EEPROM”), or flash memory (block oriented memory similar to EEPROM). Also included are any other removable storage media  580  and communication interface  590 , which allow software and data to be transferred from an external medium  595  to the system  550 . 
     System  550  may also include an input/output (“I/O”) interface  585 . The I/O interface  585  facilitates input from and output to external devices. For example the I/O interface  585  may receive input from a keyboard or mouse and may provide output to a display. The I/O interface  585  is capable of facilitating input from and output to various alternative types of human interface and machine interface devices alike. 
     System  550  may also include a communication interface  590 . The communication interface  590  allows software and data to be transferred between system  550  and external devices (e.g. printers), networks, or information sources. For example, computer software or executable code may be transferred to system  550  from a network server via communication interface  590 . Examples of communication interface  590  include a modem, a network interface card (“NIC”), a wireless data card, a communications port, a PCMCIA slot and card, an infrared interface, and an IEEE 1394 fire-wire, just to name a few. 
     Communication interface  590  preferably implements industry promulgated protocol standards, such as Ethernet IEEE 802 standards, Fiber Channel, digital subscriber line (“DSL”), asynchronous digital subscriber line (“ADSL”), frame relay, asynchronous transfer mode (“ATM”), integrated digital services network (“ISDN”), personal communications services (“PCS”), transmission control protocol/Internet protocol (“TCP/IP”), serial line Internet protocol/point to point protocol (“SLIP/PPP”), and so on, but may also implement customized or non-standard interface protocols as well. 
     Software and data transferred via communication interface  590  are generally in the form of electrical communication signals  605 . These signals  605  are preferably provided to communication interface  590  via a communication channel  600 . In one embodiment, the communication channel  600  may be a wired or wireless network, or any variety of other communication links. Communication channel  600  carries signals  605  and can be implemented using a variety of wired or wireless communication means including wire or cable, fiber optics, conventional phone line, cellular phone link, wireless data communication link, radio frequency (“RF”) link, or infrared link, just to name a few. 
     Computer executable code (i.e., computer programs or software) is stored in the main memory  565  and/or the secondary memory  570 . Computer programs can also be received via communication interface  590  and stored in the main memory  565  and/or the secondary memory  570 . Such computer programs, when executed, enable the system  550  to perform the various functions of the present invention as previously described. 
     In this description, the term “computer readable medium” is used to refer to any non-transitory computer readable storage media used to provide computer executable code (e.g., software and computer programs) to the system  550 . Examples of these media include main memory  565 , secondary memory  570  (including internal memory  575 , removable medium  580 , and external storage medium  595 ), and any peripheral device communicatively coupled with communication interface  590  (including a network information server or other network device). These non-transitory computer readable mediums are means for providing executable code, programming instructions, and software to the system  550 . 
     In an embodiment that is implemented using software, the software may be stored on a computer readable medium and loaded into the system  550  by way of removable medium  580 , I/O interface  585 , or communication interface  590 . In such an embodiment, the software is loaded into the system  550  in the form of electrical communication signals  605 . The software, when executed by the processor  560 , preferably causes the processor  560  to perform the inventive features and functions previously described herein. 
     The system  550  also includes optional wireless communication components that facilitate wireless communication over a voice and over a data network. The wireless communication components comprise an antenna system  610 , a radio system  615  and a baseband system  620 . In the system  550 , radio frequency (“RF”) signals are transmitted and received over the air by the antenna system  610  under the management of the radio system  615 . 
     In one embodiment, the antenna system  610  may comprise one or more antennae and one or more multiplexors (not shown) that perform a switching function to provide the antenna system  610  with transmit and receive signal paths. In the receive path, received RF signals can be coupled from a multiplexor to a low noise amplifier (not shown) that amplifies the received RF signal and sends the amplified signal to the radio system  615 . 
     In alternative embodiments, the radio system  615  may comprise one or more radios that are configured to communicate over various frequencies. In one embodiment, the radio system  615  may combine a demodulator (not shown) and modulator (not shown) in one integrated circuit (“IC”). The demodulator and modulator can also be separate components. In the incoming path, the demodulator strips away the RF carrier signal leaving a baseband receive audio signal, which is sent from the radio system  615  to the baseband system  620 . 
     If the received signal contains audio information, then baseband system  620  decodes the signal and converts it to an analog signal. Then the signal is amplified and sent to a speaker. The baseband system  620  also receives analog audio signals from a microphone. These analog audio signals are converted to digital signals and encoded by the baseband system  620 . The baseband system  620  also codes the digital signals for transmission and generates a baseband transmit audio signal that is routed to the modulator portion of the radio system  615 . The modulator mixes the baseband transmit audio signal with an RF carrier signal generating an RF transmit signal that is routed to the antenna system and may pass through a power amplifier (not shown). The power amplifier amplifies the RF transmit signal and routes it to the antenna system  610  where the signal is switched to the antenna port for transmission. 
     The baseband system  620  is also communicatively coupled with the processor  560 . The central processing unit  560  has access to data storage areas  565  and  570 . The central processing unit  560  is preferably configured to execute instructions (i.e., computer programs or software) that can be stored in the memory  565  or the secondary memory  570 . Computer programs can also be received from the baseband processor  610  and stored in the data storage area  565  or in secondary memory  570 , or executed upon receipt. Such computer programs, when executed, enable the system  550  to perform the various functions of the present invention as previously described. For example, data storage areas  565  may include various software modules (not shown) that are executable by processor  560 . 
     Various embodiments may also be implemented primarily in hardware using, for example, components such as application specific integrated circuits (“ASICs”), or field programmable gate arrays (“FPGAs”). Implementation of a hardware state machine capable of performing the functions described herein will also be apparent to those skilled in the relevant art. Various embodiments may also be implemented using a combination of both hardware and software. 
     Furthermore, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and method steps described in connection with the above described figures and the embodiments disclosed herein can often be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled persons can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the invention. In addition, the grouping of functions within a module, block, circuit or step is for ease of description. Specific functions or steps can be moved from one module, block or circuit to another without departing from the invention. 
     Moreover, the various illustrative logical blocks, modules, and methods described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor (“DSP”), an ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     Additionally, the steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium including a network storage medium. An exemplary storage medium can be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can also reside in an ASIC. 
     The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly not limited.