Patent Publication Number: US-9843401-B2

Title: Detection and mitigation of ingress interference within communication links

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of and claims priority to U.S. patent application Ser. No. 14/479,887, filed Sep. 8, 2014, which is a Continuation of and claims priority to U.S. patent application Ser. No. 13/487,408, filed Jun. 4, 2012. The contents of the foregoing are hereby incorporated by reference into this application as if set forth herein in full. 
    
    
     FIELD OF THE DISCLOSURE 
     The subject disclosure relates generally to satellite communications and more specifically to failover operation of redundant elements of a satellite communication system. 
     BACKGROUND 
     Satellite earth terminals receive downlink streams from one or more satellite transponders, for example, operating in the C/Ku frequency bands. High bandwidth signals, such as multimedia signals, are generally received from a satellite using a high gain antenna. An example of such an antenna includes a dish reflector directing energy into a feed horn. The received broadcast signals, or streams, are generally grouped according to satellite transponders, with each transponder assigned a respective non-overlapping portion of the spectrum, or bandwidth. The received satellite signals are amplified and down converted, for example, by a device commonly referred to as an LNB—a combined Low Noise Amplifier (LNA) and block down converter. The LNB is typically located as close as possible to the satellite feed horn, down converting a group of transponder signals (e.g., sixteen) to an intermediate frequency. It is common in video broadcast applications for the intermediate frequency to be located within a portion of the electromagnetic spectrum referred to as L-band. 
     L-band represents a crowded region of the electromagnetic spectrum, supporting many activities, such as aeronautical radio-navigation, radio astronomy and maritime mobile satellite. Use of this region of spectrum, as described herein, related to video broadcast satellite applications, is not considered by frequency management organizations, such as the Federal Communications Commission (FCC) in the allocation of authorized users. Use of the L-band by video broadcast satellite users, is considered unnecessary, as they are referred to as “wired carriers.” Although over-the-air signals are received in the C and Ku bands, the L-band intermediate frequency signals are transported from the LNB using cables or waveguides. Since the intermediate-frequency signals are protected from exposure to the ambient electromagnetic environment, it is presumed that sufficient protection from any radiated signals in the same frequency band will be provided by the wired carrier&#39;s cable or waveguide shielding. Unfortunately, problems can occur due to breaches in the cable or waveguide. Such breaches may result from corrosion, loose interconnections or water ingress. Such conditions left untreated would allow for ingress of ambient electromagnetic energy, which could, depending upon such features as amplitude, frequency and modulation, interfere with operation of the video broadcast satellite receiver system. 
     Fortunately, most of authorized L-band uses are relatively low power, such that any unwanted interference that happens to fall within the L-band may not result in perceptible interference to the video broadcast system. It may go undetected altogether. However, as utilization of the electromagnetic spectrum grows, it is likely that new applications may operate at higher levels. In particular, one potential application is 4G wireless broadband communications network that may operate terrestrial communications within the L-band (e.g., at 1525 and 1559 MHz). Such operations would likely operate at relatively high power, such that interference would result in perceptible interference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIGS. 1-2  depict illustrative embodiments of communication systems that provide media services; 
         FIG. 3  depicts an illustrative embodiment of a web portal for interacting with the communication systems of  FIGS. 1-2 ; 
         FIG. 4  depicts an illustrative embodiment of a communication device utilized in the communication systems of  FIGS. 1-2 ; 
         FIG. 5  depicts an illustrative embodiment of a satellite receiver system utilized in  FIG. 1 , that switches out redundant components upon detected interference; 
         FIG. 6  depicts an illustrative spectrum of sampled electromagnetic energy within an intermediate frequency communication link of the satellite receiver utilized in  FIG. 1  and  FIG. 6 ; 
         FIG. 7  depicts an illustrative block diagram of an interference monitor utilized in  FIG. 5 ; 
         FIG. 8  depicts an illustrative embodiment of a method operating in portions of the systems described in  FIGS. 1-7 ; and 
         FIG. 9  is a diagrammatic representation of a machine in the form of a computer system within which a set of instructions, when executed, may cause the machine to perform any one or more of the methods described herein. 
     
    
    
     DETAILED DESCRIPTION 
     The subject disclosure describes, among other things, illustrative embodiments of a system and process for detecting occurrences of unintended signals coupling into a communications link carrying a down-converted satellite signal from an earth terminal. Depending upon the nature of any such detected unintended signals, the communications link can be “swapped” out for a redundant communications link carrying a down-converted format of the same satellite signal obtained from a redundant earth terminal. Other embodiments are contemplated by the subject disclosure. 
     One embodiment of the subject disclosure includes a process, including receiving, by a system including at least one processor, by way of a first communications link, a down-converted satellite signal occupying a portion of an intermediate-frequency bandwidth. The down-converted satellite signal is provided by the system to a decoder that decodes the down-converted satellite signal resulting in a decoded broadcast signal for distribution through a multimedia distribution network. A redundant down-converted satellite signal is received by the system, by way of a second communications link. The redundant down-converted satellite signal occupies a portion of the intermediate-frequency bandwidth. An unintended signal is detected, by the system, within the intermediate-frequency bandwidth of the first communications link. A likelihood of interference with unintended signal is determined, by the system, for the received broadcast signal. Upon detecting the likelihood of interference exceeding a threshold, the down-converted satellite signal is substituted, by the system, at the receiver with the redundant down-converted satellite signal. 
     One embodiment of the subject disclosure includes a system, including a memory storing computer instructions; and a processor coupled to the memory, wherein the processor, responsive to executing the computer instructions, performs operations including receiving, by a system including at least one processor, by way of a first communications link, a down-converted satellite signal occupying a portion of an intermediate-frequency bandwidth. The down-converted satellite signal is provided by the system to a decoder that decodes the down-converted satellite signal resulting in a decoded broadcast signal for distribution through a multimedia distribution network. A redundant down-converted satellite signal is received by the system, by way of a second communications link. The redundant down-converted satellite signal occupies a portion of the intermediate-frequency bandwidth. An unintended signal is detected, by the system, within the intermediate-frequency bandwidth of the first communications link. A likelihood of interference with unintended signal is determined, by the system, for the received broadcast signal. Upon detecting the likelihood of interference exceeding a threshold, the down-converted satellite signal is substituted, by the system, at the receiver with the redundant down-converted satellite signal. 
     One embodiment of the subject disclosure includes a non-transitory computer-readable storage medium, comprising computer instructions which, responsive to being executed by at least one processor, cause the at least one processor to perform operations comprising detecting, by a system including at least one processor, an unintended signal within a communication link of a satellite receiver. Determining likelihood of interference from the unintended signal that causes signal distortion at end user equipment receiving a signal conveyed by the communication link of the satellite receiver. Responsive to detecting that a likelihood of interference exceeds a threshold, a communications link of a satellite receiver is substituted with a redundant communications link of the satellite receiver, conveying the same signal as the communication link. 
       FIG. 1  depicts an illustrative embodiment of a first communication system  100  for delivering media content. The communication system  100  can represent an Internet Protocol Television (IPTV) media system. The IPTV media system can include a super head-end office (SHO)  110  with at least one super headend office server (SHS)  111  which receives media content from satellite  113  and/or terrestrial communication systems. The satellite communication system  113  can include one or more of the features disclosed herein. In the present context, media content can represent, for example, audio content, moving image content such as 2D or 3D videos, video games, virtual reality content, still image content, and combinations thereof. The SHS server  111  can forward packets associated with the media content to one or more video head-end servers (VHS)  114  via a network of video head-end offices (VHO)  112  according to a common multicast communication protocol. 
     The VHS  114  can distribute multimedia broadcast content via an access network  118  to commercial and/or residential buildings  102  housing a gateway  104  (such as a residential or commercial gateway). The access network  118  can represent a group of digital subscriber line access multiplexers (DSLAMs) located in a central office or a service area interface that provide broadband services over fiber optical links or copper twisted pairs  119  to buildings  102 . The gateway  104  can use common communication technology to distribute broadcast signals to media processors  106  such as Set-Top Boxes (STBs) which in turn present broadcast channels to media devices  108  such as computers or television sets managed in some instances by a media controller  107  (such as an infrared or RF remote controller). 
     The gateway  104 , the media processors  106 , and media devices  108  can utilize tethered communication technologies (such as coaxial, powerline or phone line wiring) or can operate over a wireless access protocol such as Wireless Fidelity (WiFi), Bluetooth, Zigbee, or other present or next generation local or personal area wireless network technologies. By way of these interfaces, unicast communications can also be invoked between the media processors  106  and subsystems of the IPTV media system for services such as video-on-demand (VoD), browsing an electronic programming guide (EPG), or other infrastructure services. 
     A satellite broadcast television system  129  can be used also in the media system of  FIG. 1 . The satellite broadcast television system can be overlaid, operably coupled with, or replace the IPTV system as another representative embodiment of communication system  100 . In this embodiment, signals transmitted by a satellite  115  carrying media content can be received by a satellite dish receiver  131  coupled to the building  102 . Modulated signals received by the satellite dish receiver  131  can be transferred to the media processors  106  for demodulating, decoding, encoding, and/or distributing broadcast channels to the media devices  108 . The media processors  106  can be equipped with a broadband port to the ISP network  132  to enable interactive services such as VoD and EPG as described above. 
     In yet another embodiment, an analog or digital cable broadcast distribution system such as cable TV system  133  can be overlaid, operably coupled with, or replace the IPTV system and/or the satellite TV system as another representative embodiment of communication system  100 . In this embodiment, the cable TV system  133  can also provide Internet, telephony, and interactive media services. 
     It is contemplated that the subject disclosure can apply to other present or next generation over-the-air and/or landline media content services system. 
     Some of the network elements of the IPTV media system can be coupled to one or more computing devices  130 , a portion of which can operate as a web server for providing web portal services over an Internet Service Provider (ISP) network  132  to wireline media devices  108  or wireless communication devices  116 . 
     Communication system  100  can also provide for all or a portion of the computing devices  130  to function as a network management controller (herein referred to as network management controller  130 ). The network management controller  130  can use computing and communication technology to perform function  162 , which can include among other things, a fault management process, configuration management process, performance management process and/or security management process. Such features can control rules for establishing a controlled failover or switchover of redundant satellite communications links in response to various events, such as a detection of interference, receipt of an alarm, or the like. 
     It is further contemplated that multiple forms of media services can be offered to media devices over landline technologies such as those described above. Additionally, media services can be offered to media devices by way of a wireless access base station  117  operating according to common wireless access protocols such as Global System for Mobile or GSM, Code Division Multiple Access or CDMA, Time Division Multiple Access or TDMA, Universal Mobile Telecommunications or UMTS, World interoperability for Microwave or WiMAX, Software Defined Radio or SDR, Long Term Evolution or LTE, and so on. Other present and next generation wide area wireless network technologies are contemplated by the subject disclosure. 
       FIG. 2  depicts an illustrative embodiment of a communication system  200  employing an IP Multimedia Subsystem (IMS) network architecture to facilitate the combined services of circuit-switched and packet-switched systems. Communication system  200  can be overlaid or operably coupled with communication system  100  as another representative embodiment of communication system  100 . 
     Communication system  200  can comprise a Home Subscriber Server (HSS)  240 , a tElephone NUmber Mapping (ENUM) server  230 , and other common network elements of an IMS network  250 . The IMS network  250  can establish communications between IMS-compliant communication devices (CDs)  201 ,  202 , Public Switched Telephone Network (PSTN) CDs  203 ,  205 , and combinations thereof by way of a Media Gateway Control Function (MGCF)  220  coupled to a PSTN network  260 . The MGCF  220  need not be used when a communication session involves IMS CD to IMS CD communications. A communication session involving at least one PSTN CD may utilize the MGCF  220 . 
     IMS CDs  201 ,  202  can register with the IMS network  250  by contacting a Proxy Call Session Control Function (P-CSCF) which communicates with an interrogating CSCF (I-CSCF), which in turn, communicates with a Serving CSCF (S-CSCF) to register the CDs with the HSS  240 . To initiate a communication session between CDs, an originating IMS CD  201  can submit a Session Initiation Protocol (SIP INVITE) message to an originating P-CSCF  204  which communicates with a corresponding originating S-CSCF  206 . The originating S-CSCF  206  can submit the SIP INVITE message to one or more application servers (ASs)  217  that can provide a variety of services to IMS subscribers. 
     For example, the application servers  217  can be used to perform originating call feature treatment functions on the calling party number received by the originating S-CSCF  206  in the SIP INVITE message. Originating treatment functions can include determining whether the calling party number has international calling services, call ID blocking, calling name blocking, 7-digit dialing, and/or is requesting special telephony features (e.g., *72 forward calls, *73 cancel call forwarding, *67 for caller ID blocking, and so on). Based on initial filter criteria (iFCs) in a subscriber profile associated with a CD, one or more application servers may be invoked to provide various call originating feature services. 
     Additionally, the originating S-CSCF  206  can submit queries to the ENUM system  230  to translate an E.164 telephone number in the SIP INVITE message to a SIP Uniform Resource Identifier (URI) if the terminating communication device is IMS-compliant. The SIP URI can be used by an Interrogating CSCF (I-CSCF)  207  to submit a query to the HSS  240  to identify a terminating S-CSCF  214  associated with a terminating IMS CD such as reference  202 . Once identified, the I-CSCF  207  can submit the SIP INVITE message to the terminating S-CSCF  214 . The terminating S-CSCF  214  can then identify a terminating P-CSCF  216  associated with the terminating CD  202 . The P-CSCF  216  may then signal the CD  202  to establish Voice over Internet Protocol (VoIP) communication services, thereby enabling the calling and called parties to engage in voice and/or data communications. Based on the iFCs in the subscriber profile, one or more application servers may be invoked to provide various call terminating feature services, such as call forwarding, do not disturb, music tones, simultaneous ringing, sequential ringing, etc. 
     In some instances the aforementioned communication process is symmetrical. Accordingly, the terms “originating” and “terminating” in  FIG. 2  may be interchangeable. It is further noted that communication system  200  can be adapted to support video conferencing. In addition, communication system  200  can be adapted to provide the IMS CDs  201 ,  202  with the multimedia and Internet services of communication system  100  of  FIG. 1 . 
     If the terminating communication device is instead a PSTN CD such as CD  203  or CD  205  (in instances where the cellular phone only supports circuit-switched voice communications), the ENUM system  230  can respond with an unsuccessful address resolution which can cause the originating S-CSCF  206  to forward the call to the MGCF  220  via a Breakout Gateway Control Function (BGCF)  219 . The MGCF  220  can then initiate the call to the terminating PSTN CD over the PSTN network  260  to enable the calling and called parties to engage in voice and/or data communications. 
     It is further appreciated that the CDs of  FIG. 2  can operate as wireline or wireless devices. For example, the CDs of  FIG. 2  can be communicatively coupled to a cellular base station  221 , a femtocell, a WiFi router, a DECT base unit, or another suitable wireless access unit to establish communications with the IMS network  250  of  FIG. 2 . The cellular access base station  221  can operate according to common wireless access protocols such as Global System for Mobile (GSM), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Universal Mobile Telecommunications (UMTS), World interoperability for Microwave (WiMAX), Software Defined Radio (SDR), Long Term Evolution (LTE), and so on. Other present and next generation wireless network technologies are contemplated by the subject disclosure. Accordingly, multiple wireline and wireless communication technologies are contemplated for the CDs of  FIG. 2 . 
     It is further contemplated that cellular phones supporting LTE can support packet-switched voice and packet-switched data communications and thus may operate as IMS-compliant mobile devices. In this embodiment, the cellular base station  221  may communicate directly with the IMS network  250  as shown by the arrow connecting the cellular base station  221  and the P-CSCF  216 . 
     It is further understood that alternative forms of a CSCF can operate in a device, system, component, or other form of centralized or distributed hardware and/or software. Indeed, a respective CSCF may be embodied as a respective CSCF system having one or more computers or servers, either centralized or distributed, where each computer or server may be configured to perform or provide, in whole or in part, any method, step, or functionality described herein in accordance with a respective CSCF. Likewise, other functions, servers and computers described herein, including but not limited to, the HSS and ENUM server, the BGCF, and the MGCF, can be embodied in a respective system having one or more computers or servers, either centralized or distributed, where each computer or server may be configured to perform or provide, in whole or in part, any method, step, or functionality described herein in accordance with a respective function, server, or computer. 
     The network management controller  130  of  FIG. 1  can be operably coupled to the second communication system  200  for purposes similar to those described above. It is further contemplated by the subject disclosure that network management controller  130  can perform function  162 . 
     The network management controller  130  of  FIG. 1  can be operably coupled to the second communication system  200  for purposes similar to those described above. It is further contemplated by the subject disclosure that the application server  217  can be adapted to perform function  162 . 
       FIG. 3  depicts an illustrative embodiment of a web portal  302  which can be hosted by server applications operating from the computing devices  130  of the communication system  100  illustrated in  FIG. 1 . The web portal  302  can be used for managing services of communication systems  100 - 200 . A web page of the web portal  302  can be accessed by a Uniform Resource Locator (URL) with an Internet browser such as Microsoft&#39;s Internet Explorer™, Mozilla&#39;s Firefox™, Apple&#39;s Safari™, or Google&#39;s Chrome™ using an Internet-capable communication device such as those described in  FIGS. 1-2 . The web portal  302  can be configured, for example, to access a media processor  106  and services managed thereby such as a Digital Video Recorder (DVR), a Video on Demand (VoD) catalog, an Electronic Programming Guide (EPG), or a personal catalog (such as personal videos, pictures, audio recordings, etc.) stored at the media processor  106 . The web portal  302  can also be used for provisioning IMS services described earlier, provisioning Internet services, provisioning cellular phone services, and so on. 
     It is contemplated by the subject disclosure that the web portal  302  can further be utilized to manage and provision the network  162  to adapt the network as may be desired by network managers. 
       FIG. 4  depicts an illustrative embodiment of a communication device  400 . Communication device  400  can serve in whole or in part as an illustrative embodiment of the devices depicted in  FIGS. 1-2 . The communication device  400  can comprise a wireline and/or wireless transceiver  402  (herein transceiver  402 ), a user interface (UI)  404 , a power supply  414 , a location receiver  416 , a motion sensor  418 , an orientation sensor  420 , and a controller  406  for managing operations thereof. The transceiver  402  can support short-range or long-range wireless access technologies such as Bluetooth, ZigBee, WiFi, Digital Enhanced Cordless Telecommunications (DECT), or cellular communication technologies, just to mention a few. Cellular technologies can include, for example, CDMA-1X, UMTS/HSDPA, GSM/GPRS, TDMA/EDGE, EV/DO, WiMAX, software defined radio (SDR), Long Term Evolution (LTE), as well as other next generation wireless communication technologies as they arise. The transceiver  402  can also be adapted to support circuit-switched wireline access technologies (such as PSTN), packet-switched wireline access technologies (such as TCP/IP, VoIP, etc.), and combinations thereof. 
     The UI  404  can include a depressible or touch-sensitive keypad  408  with a navigation mechanism such as a roller ball, a joystick, a mouse, or a navigation disk for manipulating operations of the communication device  400 . The keypad  408  can be an integral part of a housing assembly of the communication device  400  or an independent device operably coupled thereto by a tethered wireline interface (such as a USB cable) or a wireless interface supporting for example Bluetooth. The keypad  408  can represent a numeric keypad commonly used by phones, and/or a QWERTY keypad with alphanumeric keys. The UI  404  can further include a display  410  such as monochrome or color LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode) or other suitable display technology for conveying images to an end user of the communication device  400 . In an embodiment where the display  410  is touch-sensitive, a portion or all of the keypad  408  can be presented by way of the display  410  with navigation features. 
     The display  410  can use touch screen technology to also serve as a user interface for detecting user input (e.g., touch of a user&#39;s finger). As a touch screen display, the communication device  400  can be adapted to present a user interface with graphical user interface (GUI) elements that can be selected by a user with a touch of a finger. The touch screen display  410  can be equipped with capacitive, resistive or other forms of sensing technology to detect much surface area of a user&#39;s finger has been placed on a portion of the touch screen display. This sensing information can be used control the manipulation of the GUI elements. 
     The UI  404  can also include an audio system  412  that utilizes common audio technology for conveying low volume audio (such as audio heard only in the proximity of a human ear) and high volume audio (such as speakerphone for hands free operation). The audio system  412  can further include a microphone for receiving audible signals of an end user. The audio system  412  can also be used for voice recognition applications. The UI  404  can further include an image sensor  413  such as a charged coupled device (CCD) camera for capturing still or moving images. 
     The power supply  414  can utilize common power management technologies such as replaceable and rechargeable batteries, supply regulation technologies, and charging system technologies for supplying energy to the components of the communication device  400  to facilitate long-range or short-range portable applications. Alternatively, the charging system can utilize external power sources such as DC power supplied over a physical interface such as a USB port. The location receiver  416  can utilize common location technology such as a global positioning system (GPS) receiver capable of assisted GPS for identifying a location of the communication device  400  based on signals generated by a constellation of GPS satellites, thereby facilitating common location services such as navigation. The motion sensor  418  can utilize motion sensing technology such as an accelerometer, a gyroscope, or other suitable motion sensing to detect motion of the communication device  400  in three-dimensional space. The orientation sensor  420  can utilize orientation sensing technology such as a magnetometer to detect the orientation of the communication device  400  (North, South, West, East, combined orientations thereof in degrees, minutes, or other suitable orientation metrics). 
     The communication device  400  can use the transceiver  402  to also determine a proximity to a cellular, WiFi, Bluetooth, or other wireless access points by common sensing techniques such as utilizing a received signal strength indicator (RSSI) and/or a signal time of arrival (TOA) or time of flight (TOF). The controller  406  can utilize computing technologies such as a microprocessor, a digital signal processor (DSP), and/or a video processor with associated storage memory such as Flash, ROM, RAM, SRAM, DRAM or other storage technologies. 
     Other components not shown in  FIG. 4  are contemplated by the subject disclosure. For instance, the communication device  400  can include a reset button (not shown). The reset button can be used to reset the controller  406  of the communication device  400 . In yet another embodiment, the communication device  400  can also include a factory default setting button positioned below a small hole in a housing assembly of the communication device  400  to force the communication device  400  to re-establish factory settings. In this embodiment, a user can use a protruding object such as a pen or paper clip tip to reach into the hole and depress the default setting button. 
     The communication device  400  as described herein can operate with more or less components described in  FIG. 4 . These variant embodiments are contemplated by the subject disclosure. 
     The communication device  400  can be adapted to perform the functions of the media processor  106 , the media devices  108 , or the portable communication devices  116  of  FIG. 1 , as well as the IMS CDs  201 - 202  and PSTN CDs  203 - 205  of  FIG. 2 . It will be appreciated that the communication device  400  can also represent other common devices that can operate in communication systems  100 - 200  of  FIGS. 1-2  such as a gaming console and a media player. 
     It is contemplated by the subject disclosure that the communication device  400  shown in  FIG. 4  or portions thereof can serve as a representation of one or more of the devices of communication systems  100 - 200 . It is further contemplated that the controller  406  can be adapted in various embodiments to perform the function  162 . 
     It is contemplated by the subject disclosure that the satellite receiver system  500  shown in  FIG. 5  or portions thereof can serve as a representation of one or more of the devices of communication systems  100 - 200 . As part of a satellite communication system, multimedia broadcast signals are broadcast from a satellite  502 . The multimedia signals broadcast from the satellite  502  within one or more of the C/Ku bands, or other suitable frequency bands, are received by a satellite earth terminal  504   a , located within a footprint on the surface of the earth of the satellite&#39;s transponder(s) carrying the intended broadcast. The satellite earth terminal  504  may contain a high gain antenna, such as a reflector antenna, directing received signals into a feed horn. The received signals are routed from the feed horn to a nearby LNB  508   a , within which they are amplified and down-converted to an intermediate frequency. In the illustrative examples discussed herein, the intermediate frequency band is a portion of the electromagnetic spectrum, generally known as the L-band, extending from about 950 MHz to about 2,100 MHz. An L-band output signal, generally preserving the satellite transponder signals, is routed to a receiver facility  506 , for example, at the SHO  110  ( FIG. 1 ). In particular, the L-band output of the LNB can be routed from the satellite earth terminal  504   a  to a nearby equipment shed, using a low-loss, shielded waveguide, such as a hard-line coaxial cable assembly  510   a . At the equipment shed, the L-band radio frequency signal can be converted to an optical signal and routed over a fiber optic link  512   a  to the receiver facility  506 , whereupon the optical signal transported over the fiber optic network  512   a  is again converted back into a radio frequency L-band signal. 
     Also shown, is a redundant satellite earth terminal  504   b , located within the same footprint of the satellite&#39;s broadcast. The redundant satellite earth terminal  504   b  may contain a high gain antenna, a feed horn and a nearby LNB  508   b . An L-band output signal, preserving the satellite transponder signals is routed to the same receiver facility  506 . In particular, the L-band output of the LNB  508   b  can be routed in a similar manner from the satellite earth terminal  504   b  to a nearby equipment shed, again using a low-loss, shielded waveguide, such as a hard-line coaxial cable assembly  510   b . At the equipment shed, the redundant L-band radio frequency signal can be converted to an optical signal and routed over a second fiber optic link  512   b , albeit much longer, to the same receiver facility  506 , whereupon the optical signal transported over the fiber optic network  512   b  is once again converted back into a redundant radio frequency L-band signal, carried in a respective coaxial cable  514   a . In at least some applications, the redundant satellite earth terminal  504   b  is geographically remote from the first satellite earth terminal  504   a . For example, the satellite earth terminal  504   a  and the redundant satellite earth terminal  504   b  are separated by more than a radio line of sight distance between them. 
     Each of the respective L-band satellite broadcast signals received at the receiver facility  506  can be split, for example, using a respective passive splitter device  516   a ,  5   a   6   b , into a group of substantially identical L-band signals, e.g., sixteen such signals. Each group of L-band signals can be coupled to a respective group of input ports of a switch  518 . The switch  518  is referred to as a 2:1, or redundancy, or failover switch. The switch  518  selectively couples one of the groups of signals from a respective one of the passive splitters  516   a ,  516   b , to a common output group of L-band signal ports. Thus, at any given time, only one of the groups of L-band signals from a respective one of the passive splitters  516   a ,  516   b  is in electrical communication with the output group of L-band signal ports. In at least some embodiments, the switch  518  has a control input that can be driven by a controller, such as a network management controller  520 . 
     Each L-band output port of the switch  518  can be coupled to a respective integrated receiver and decoder device  522  of a bank of such devices  522 . The integrated receiver decoder devices  522 , generally down convert the L-band radio frequency signal and otherwise decode it to obtain baseband data. Each one of the bank of integrated receiver and decoder devices  522  can be used to obtain digital information from a respective one of the satellite transponders. The transponders can broadcast signals that are tens of MHz wide. For example, each decoded transponder signal might include 5 or 6 high-definition video streams, or 12 to 15 standard definition video streams. Additional multiplexing can be applied, for example, to extract one or more streams from each of the transponder signals. 
     In at least some embodiments, a multiplexer  524  or similar switching or reconfiguration device is coupled between the L-band output ports of the switch  518  and the bank of integrated receiver and decoder devices  522 . Such a multiplexer  524  can also be operated under the control of the network management controller  520 . Thus, the network management controller  520  can control which satellite earth terminal  504   a ,  504   b  is being used for signal reception at the receiver facility  506 , and how the split L-band signals are interconnected or otherwise routed to respective ones of the bank of integrated receiver and decoder devices  522 . 
     Operation of the failover switch  518  can be undertaken for any of a number of different reasons, generally to ensure as little or no interruption to data service to end users or subscribers of the multimedia content. For example, satellite earth terminals require occasional scheduled maintenance. During such periods of maintenance at one of the satellite earth terminal  504   a , the switch can be operated to obtain satellite signals from the redundant satellite earth terminal  504   b . Such a pre-scheduled switchover can be accomplished during periods of lower viewer activity, and preferably coincident with an event, such between programs, or aligned with data frames, so as to minimize any interruption to the end users. 
     Alternatively or in addition, the  2 : 1  switch  518  can be operated to make a similar change between the satellite earth terminal  504   a  and the redundant satellite earth terminal  504   b  for unscheduled operational reasons. An example of such a reason might include weather at one satellite earth terminal  504   a  reducing a link margin and leading to a reduction in a ratio of energy per bit to noise power spectral density (E b /N 0 ). Due to the geographical separation, the same weather may not be affecting the other satellite earth terminal  504   b . In this situation, a switch to the redundant satellite earth terminal  504   b  should restore or otherwise maintain reliable delivery of multimedia service. Still other reasons may relate to hardware issues or a satellite earth terminal&#39;s position within the transponder footprint. Such issues may result in a reduction of received signal amplitude, otherwise compromising E b /N 0  performance. In each of these scenarios, the network management controller  520  can impose a switchover, for example, upon scheduled events and/or upon monitoring degradation to E b /N 0 . It should be noted, however, that such events requiring an unscheduled switchover typically result from a reduction in the received signal energy of the intended signal(s). 
     Also shown in  FIG. 5 , is a source of interfering electromagnetic energy  526  residing within the general vicinity of the satellite earth terminal  504   a  (e.g., within radio line of sight). For example, the source can result from an unrelated terrestrial communication link. To the extent that the shielding and interconnections of the hard-line coaxial cable assembly of the first communications link are functioning properly, the cable shielding should provide sufficient protection to prevent ingress of the interfering electromagnetic energy  526 . However, to the extent that the hard-line coaxial cable assembly  510   a  has been compromised in any way, for example, by having a loose connector, a cut shield, corrosion, or water ingress, such compromises may allow ingress of the interfering electromagnetic energy  526  into the intermediate frequency, e.g., L-band, communications link. Depending upon characteristics of the ingress of the interferer  124 , its presence within the communication link can lead to perceived errors by the end users, without necessarily leading to a reduction in E b /N 0 . 
     Referring next to  FIG. 6 , a spectral representation  600  of an example down-converted L-band signal is shown. The signal includes a number of adjacent, non-overlapping signal spectra  602   a ,  602   b ,  602   c ,  602   d  and  602   e  (generally  602 ), resulting from contributions of individual transponders of the satellite  502  ( FIG. 5 ). Also represented are two interfering signals  604  and  606  resulting from ingress of unintended signals into the L-band communications link. A first one of the interfering signals  604  is centered at a frequency F 1 , and may result from a fundamental frequency of the interfering electromagnetic energy  526  ( FIG. 5 ). For example, the first interfering signal might result from one of the LightSquared broadcast signals at one of the two center frequencies: 5 L/10 L centered around established frequencies of 1528 MHz and 5 H/10 H centered around 1552 MHz. If the interfering electromagnetic energy  526  is strong enough, it is possible that one or more of the interfering signals  604 ,  606  may result from harmonics, triple beat products, or other non-linear interference, that may occur at unpredictable frequencies, e.g., F 2 . 
     Referring again to  FIG. 5 , an interference monitoring module  528   a  is coupled to an output port of the first passive splitter  516   a , receiving a respective sample of the intermediate frequency, L-band signal obtained from the satellite earth terminal  504   a  through the first communications link, which includes the hard-line coaxial cable  510   a , the fiber optic link  512   a  and any intervening components up to an input port of the interference monitoring module  528   a . In at least some embodiments, an output of the interference monitoring module  528   a  is routed to an alarm module  530 . The alarm module can be configured to generate an alarm responsive to detecting unintended signals within the first communications link that would be likely to interfere with intended L-band signals. For example, an alarm level can be established according to an absolute amplitude of the detected unintended signal  604 ,  606  ( FIG. 6 ), a relative amplitude of the detected unintended signal  604 ,  606  in comparison to another signal or noise level, or some other attribute of the detected unintended signal  604 ,  606 , such as its spectral energy, bandwidth, etc. Different alarms can be established for different scenarios. For example, alarm conditions can be categorized as “minor,” “major,” and “critical,” depending upon one or more of the amplitude, frequency, and number of detected unintended signals  604 ,  606 . 
     One or more of the interference monitoring module  528   a  and the alarm module  530  can be coupled to or otherwise in communication with the network management controller  520 . The network management controller  520 , in turn, can be programmed or otherwise configured to interpret such inputs and respond accordingly. An example of a response might include providing a network management notification as to a detection of a minor alarm, without a failover reconfiguration. In response to a major or critical alarm, the network management controller  520  can send a signal to the redundancy switch  518 , inducing a failover reconfiguration from one satellite earth terminal  504   a  to another  504   b . It is important to note that such a failover can occur not from detecting a drop in signal strength or E b /N 0 , but from in increased signal energy resulting from the presence of unintended signals within the L-band resulting from ingress into the communication link. With sufficient geographic separation between earth terminals  504   a ,  54   b , it is unlikely that the same interfering electromagnetic energy  526  would be present at the other terminal. Even if it were, the interference likely resulted from a defect of some sort, which would not necessarily exist at the alternate earth terminal. 
     In some embodiments, the network management controller  520  can be programmed or otherwise configured to generate a maintenance notice upon detection of such a failover. The maintenance notice can include particulars related to the failover event, such as the time, date, alarm type, signal strength, signal frequency, etc. Such information would be helpful to assist with correcting a compromised communication link. 
       FIG. 7  illustrates an example embodiment of an interference monitoring module  700 . The interference monitoring module  700  includes an input port  701  in communication with the sample port of the passive signal splitter  516   a  ( FIG. 5 ). A sample obtained at the sample port is coupled to a frequency selector module  702 . The frequency selector module  702  can include one or more filters, such as one or more of a notch filter, a low-pass filter, a high-pass filter, and a band-pass filter. The filters can be constructed from any suitable technology, such as lumped elements, microstrip circuits, surface acoustic wave devices, and the like. In some embodiments, it is envisioned that the obtained sample stream can be converted to a digital stream, for example, using an analog-to-digital converter. In such scenarios, filtering and other signal processing as may be advantageous within the interference monitoring module  700 , can be accomplished using digital signal processing techniques. 
     In some embodiments, the frequency selector module  702  is fixed tuned to one or more frequencies, such as established frequencies of a known interference source  528 , e.g., F 1 , F 2  ( FIG. 6 ). Such fixed tuned techniques can be advantageous to detect ingress as may result from compromise to the communications link. Alternatively or in addition, the frequency selector can be tunable. For example, the frequency selector can include one or more well established signal processing techniques to tune among more than one frequency. In some embodiments, such a tunable frequency selector  702  can be configured to tune across a substantial portion of the L-band spectral bandwidth, e.g., 900 MHz to 1,200 MHz, at a tuning step size, e.g., 0.5 MHz. Such a tunable configuration would be advantageous in tracking unknown sources of interference in addition to known sources, for example, resulting from non-linear effects including harmonics, triple beats, inter-modulation, spurious emissions, and the like. 
     An output of the frequency selector module  702  can be provided to a detector circuit  704 . For example, the detector module  704  can be a power detector, such as a square law detector. In the illustrative embodiment, an alarm module  706  is included within the interference monitoring module and in communication with the detector module  704 , obviating any need for a separate alarm module  530 , as discussed above in relation to  FIG. 5 . In at least some embodiments, one or more of the frequency selector module  702 , the detector module  704  and the alarm module  706  are contained within a shielded enclosure  708 . 
     Shielding performance of such a shielded enclosure  708  can be established according to a specified shielding rating. Such shielding would be advantageous to avoid contamination of L-band samples obtained from the communication link. For example, the shielded enclosure  708  can be configured, through acceptable practices known to those skilled in the art of mitigating electromagnetic interference, to provide a specified isolation or shielding profile across a range of frequencies. Such isolation preferably attenuates the coupling of radiated electromagnetic energy from any interfering signals, such as those resulting from interference sources within the L-band, to the detector module  704 . Preferably, any coupling of such interfering signals through the shielded enclosure  708  would be attenuated below a minimum detectable interference signal level to ensure that the detector module  704  is able to discern detected interference within the first or second communication links from radiated ambient interference present at the detector module  704 . 
       FIG. 8  depicts an illustrative process  800  that operates in portions of the devices of  FIGS. 1-7 . The process  800  can begin with step  802  in which broadcast and redundant broadcast signals are received. Such signal can include the intermediate frequency (i.e., L-band) signals received at the receiver site  506  from each of the satellite earth terminal  504   a  and the redundant satellite earth terminal  504   b  ( FIG. 5 ). The received broadcast signal can be decoded and distributed at step  804 . For example, the received L-band signal received by the first communications link can be divided by the passive splitter  516   a  ( FIG. 5 ), and routed to an appropriate number of the integrated receiver and decoder devices  522 . Outputs from the integrated receiver and decoder devices  522  can be distributed through an appropriate communications network such as those disclosed herein in relation to  FIGS. 1-4 . This could be considered a normal operation scenario. 
     At step  806 , at least a portion of the bandwidth of the first communications link carrying an intermediate frequency of the broadcast signal is monitored for any interference, such as determined by presence of an unintended signals. As long as no interference is detected at step  808 , monitoring continues under normal operations. However, upon the detection of interference at step  808 , the broadcast signal is substituted with the redundant broadcast signal. For example, the redundancy switch  518  ( FIG. 5 ) redirects redundant broadcast signals from the second passive splitter  516   b  to the bank of integrated receiver decoder devices  522 . After the failover, the integrated receiver and decoder devices  522  decode and distribute the broadcast signal at step  812  to reestablish normal operations using the redundant broadcast signal. Since the broadcast signal and the redundant broadcast signal are substantially the same, distribution of multimedia streams obtained from the satellite is maintained in a relatively seamless manner. 
     Upon reviewing the aforementioned embodiments, it would be evident to an artisan with ordinary skill in the art that said embodiments can be modified, reduced, or enhanced without departing from the scope and spirit of the claims described below. For example, instead of satellite signals, interference monitoring and redundancy can be provided for virtually any electromagnetic communications circuit, such as terrestrial communications. Also, the particular signal frequency bands, such as L-band operation for the intermediate frequency are provided as illustrative examples only, and in no way limit application of the techniques disclosed herein to other signals, and other frequency ranges of operation. Other embodiments are contemplated by the subject disclosure. 
       FIG. 9  depicts an exemplary diagrammatic representation of a machine in the form of a computer system  900  within which a set of instructions, when executed, may cause the machine to perform any one or more of the methods discussed above. One or more instances of the machine can operate, for example, as one or more of the alarm module  530 ,  706 , the network management controller  520 , the media processor  106  and other devices of  FIGS. 1-7 . In some embodiments, the machine may be connected (e.g., using a network) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client user machine in server-client user network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. 
     The machine may comprise a server computer, a client user computer, a personal computer (PC), a tablet PC, a smart phone, a laptop computer, a desktop computer, a control system, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. It will be understood that a communication device of the subject disclosure includes broadly any electronic device that provides voice, video or data communication. Further, while a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methods discussed herein. 
     The computer system  900  may include a processor  902  (e.g., a central processing unit (CPU), a graphics processing unit (GPU, or both), a main memory  904  and a static memory  906 , which communicate with each other via a bus  908 . The computer system  900  may further include a video display unit  910  (e.g., a liquid crystal display (LCD), a flat panel, or a solid state display. The computer system  900  may include an input device  912  (e.g., a keyboard), a cursor control device  914  (e.g., a mouse), a disk drive unit  916 , a signal generation device  918  (e.g., a speaker or remote control) and a network interface device  920 . 
     The disk drive unit  916  may include a tangible computer-readable storage medium  922  on which is stored one or more sets of instructions (e.g., software  924 ) embodying any one or more of the methods or functions described herein, including those methods illustrated above. The instructions  924  may also reside, completely or at least partially, within the main memory  904 , the static memory  906 , and/or within the processor  902  during execution thereof by the computer system  900 . The main memory  904  and the processor  902  also may constitute tangible computer-readable storage media. 
     Dedicated hardware implementations including, but not limited to, application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Applications that may include the apparatus and systems of various embodiments broadly include a variety of electronic and computer systems. Some embodiments implement functions in two or more specific interconnected hardware modules or devices with related control and data signals communicated between and through the modules, or as portions of an application-specific integrated circuit. Thus, the example system is applicable to software, firmware, and hardware implementations. 
     In accordance with various embodiments of the subject disclosure, the methods described herein are intended for operation as software programs running on a computer processor. Furthermore, software implementations can include, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein. 
     While the tangible computer-readable storage medium  622  is shown in an example embodiment to be a single medium, the term “tangible computer-readable storage medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “tangible computer-readable storage medium” shall also be taken to include any non-transitory medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methods of the subject disclosure. 
     The term “tangible computer-readable storage medium” shall accordingly be taken to include, but not be limited to: solid-state memories such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories, a magneto-optical or optical medium such as a disk or tape, or other tangible media which can be used to store information. Accordingly, the disclosure is considered to include any one or more of a tangible computer-readable storage medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored. 
     Although the present specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Each of the standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are from time-to-time superseded by faster or more efficient equivalents having essentially the same functions. Wireless standards for device detection (e.g., RFID), short-range communications (e.g., Bluetooth, WiFi, Zigbee), and long-range communications (e.g., WiMAX, GSM, CDMA, LTE) are contemplated for use by computer system  900 . 
     The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. 
     Although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are contemplated by the subject disclosure. 
     The Abstract of the Disclosure is provided with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.