Patent Publication Number: US-2005135628-A1

Title: System and method for authenticating components in wireless home entertainment system

Description:
RELATED APPLICATIONS  
      This application claims priority from U.S. provisional patent application Ser. No. 60/520,590, filed Nov. 17, 2003. 
    
    
     BACKGROUND OF THE INVENTION  
      I. Field of the Invention  
      The present invention relates generally to home entertainment systems.  
      II. Background  
      Wireless home entertainment systems have been provided that can include a set-top box media server that communicates over a wireless system such as an 802.11 system with various components in the home, e.g., TVs, laptop computers, and custom display devices. It is desirable that a rogue device not be permitted on the home network, which would otherwise permit the rogue device to steal content or confidential information on the network and to upload viruses into the network. Also, it is desirable that a component in one home network not mistakenly and non-maliciously gain entry into a neighboring home network.  
      Accordingly, many wireless home networks require that configuration information (e.g., encryption keys, medium access controller (MAC) addresses) be exchanged between the server and a component seeking admission to the network, prior to providing the component access to the network. The sharing of information ideally is automatically verifiable without user intervention, particularly for consumer electronic devices. Unfortunately, existing systems typically require the user to manually enter information into one or both devices, to ensure that an eavesdropping rogue device outside the home cannot gain admission to the network, and this is not desirable for many devices, e.g., consumer electronic devices. As an alternative, the server and component can be paired at the factory but this results in inflexibility, as the component can be used only with the server with which it is paired. Recognizing these drawbacks, the solutions herein are provided.  
     SUMMARY OF THE INVENTION  
      A home entertainment system includes a wireless system server having a primary communication system. The system also includes at least one wireless component having a primary communication system configured for communicating with the primary communication system of the server. The component sends configuration information to the server using a secondary communication system that is out-of-band with the primary systems. Preferably, the server also sends configuration information using its secondary communication system to the component.  
      The configuration information can include encryption keys, addresses such as MAC addresses, and identifications such as SSIDs. The primary communication system can be an 802.11 system and the server can be established by a set-top box receiver.  
      In one implementation, the secondary communication system includes at least one removable media drive and at least one media component removably engageable with the drive. In another implementation, the secondary communication system is an infrared (IR) system, and the server and the component each have a respective IR port. The configuration information is exchangeable through the ports. If desired, the configuration information is exchangeable only when the ports are aligned with each other in line of sight of each other. Or, the system can include a remote control device that establishes a relay node between the ports.  
      In yet another implementation the secondary communication system is a near field system that requires a communication distance between the component and server of less than about twenty five feet to permit exchange of the configuration information. The configuration information can be exchanged automatically between the server and component when the distance between them is within the communication distance. Or, the configuration information is exchanged between the server and component only when the distance between them is within the communication distance and a user manipulates at least one button on at least one of the server, and the component.  
      In another aspect, a home entertainment system includes a wireless system server having a primary communication system, and at least one wireless component having a primary communication system configured for communicating with the primary communication system of the server. The component sends configuration information to the server using the primary communication system. The server and/or the component determines a value of a physical parameter of a signal received from the other and affirms proper exchange of information only if the value indicates that the server and component are within an acceptably close distance of each other. As an example, the parameter may be a received signal delay spread or a received distribution of signal strengths, and when the value of the parameter indicates a Rician distribution (indicating a dominant line of sight path between the transmitter and receiver), a valid configuration information exchange is indicated.  
      In yet another aspect, a method for communication between a home network server and at least one home network component includes, after the successful exchange of configuration information, communicating audio/video information over a wireless link of a primary wireless communication system. The method includes initially exchanging configuration information using a wireless link that is out-of-band with the primary wireless communication system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:  
       FIG. 1  is a block diagram of the system of the present invention; and  
       FIGS. 2-4  are flow charts of various implementations of the logic for authenticating components.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring initially to  FIG. 1 , a home entertainment system is shown, generally designated  10 , that includes a server  12  having a processor or processors  14  that may be housed in a set-top box or personal video recorder (PVR) or other component. The server  12  can receive televised content from an antenna, satellite dish, cable, etc. for display of the content on one or more of the below-described system components. The processor  14  alternatively can be incorporated into the housing of a TV to function in accordance with the disclosure herein, or it can be implemented by plural processors (e.g., one in a PVR and one in the TV or set-top box) acting in concert with each other. Or, the server  12  may be implemented by a computer such as a PC or laptop.  
      In the preferred non-limiting embodiment shown, the processors described herein may access one or more software or hardware elements to undertake the present logic. The flow charts herein illustrate the structure of the logic modules of the present invention as embodied in computer program software. Those skilled in the art will appreciate that the flow charts illustrate the structures of logic elements, such as computer program code elements or electronic logic circuits, that function according to this invention. Manifestly, the invention is practiced in its essential embodiment by a machine component that renders the logic elements in a form that instructs a digital processing apparatus (that is, a computer or microprocessor) to perform a sequence of function steps corresponding to those shown. Internal logic could be as simple as a state machine.  
      In other words, the present logic may be established as a computer program that is executed by a processor within, e.g., the present microprocessors/servers as a series of computer-executable instructions. In addition to residing on hard disk drives, these instructions may reside, for example, in RAM of the appropriate computer, or the instructions may be stored on magnetic tape, electronic read-only memory, or other appropriate data storage device.  
      The preferred server  12  shown in  FIG. 1  includes a primary wireless communication system  16 , such as an 802.11 communication system, and a secondary communication system  18  that is out-of-band with the primary system  16 . As set forth further below, the secondary communication system  18  may be a line-of-sight infrared (IR) system, in which case a television or other IR remote control device  19  may be provided. Or, the secondary communication system  18  may be a near-field communication system having an effective range of communication of, e.g., twenty five feet or less. A near-field system may be implemented by a near field “Smart Card”, and may have a frequency of between five and fifteen megaHertz (5 MHz-15 MHz) and use Amplitude Shift Keying (ASK). As understood herein, smart-card like functionality for proximal communication can be incorporated into mobile telephones or other devices. Yet again, the secondary communication system  18  may use personal area network (PAN) principles known in the art to transfer information between the server  12  and the components discussed through a person&#39;s body below when the person touches an electrode that is part of each component&#39;s secondary communication system. In such an implementation the carrier frequency may be under one megaHertz (&lt;1 MHz), and on-off shift keying may be used for modulation.  
      In addition, the server  12  can have a removable media drive  20  with which a removable media  22 , such as a Sony Memory Stick®, floppy diskette, other flash memory, universal serial bus (USB) dongles, or other removable memory media can be detachably engaged to exchange information between the server  12  and the components discussed below. The drive  20  with media  22  can be considered to be a secondary communication system that is out-of-band with the primary system  16 . One or more buttons  23  can also be provided on the server  12  for purposes to be shortly disclosed.  
       FIG. 1  shows that the system  10  includes one or more wireless components  24 , each of which wirelessly communicates with the primary communication system  16  of the server  12  using a respective primary communication system  26 . The components  24  may include, e.g., televisions, laptop computers, audio players, projectors, custom display devices, and so on. The primary communication systems are used to communicate, e.g., audio/video data streams from the server  12  to the components  24  for presentation on displays associated with the components  24 . Other data may also be transferred over the primary communication systems.  
      Each component  24  may also include a respective secondary communication system  28  that wirelessly communicates with the secondary communication system  18  of the server  12  in accordance with principles set forth below to exchange configuration information, including, e.g., encryption keys, MAC addresses, SSIDs, and other confidential information that is necessary for authentication and association and that is desired to be kept from an unauthorized device. Also, each component  24  may include a respective removable media drive  30 , and be controlled by a respective processor  32 . One or more buttons  34  may be provided on each component  24 .  
      Now referring to  FIG. 2 , one implementation of the logic for exchanging configuration information between the server  12  and components  24  can be seen. In the embodiment shown in  FIG. 2 , the removable media  22  is used to exchange the configuration information. Commencing at block  36 , the media  22  is engaged with the drive  20  of the server  12 , and configuration information of the server  12  is downloaded onto the media  22  at block  38 . Then, the media  22  is removed from the server  12  and at block  40  is engaged with the drive  30  of a component  24 .  
      Proceeding to block  42 , the configuration information of the server  12  is downloaded from the media  22  to the component  24 , and the configuration information of the component  24  is copied onto the media  22 . Then, at block  44  the media  22  is removed from the component  24  and reengaged with the drive  20  of the server  12 , which downloads the configuration information of the component  24  to complete the configuration information exchange out-of-band with the primary communication systems  16 ,  26 . It is to be understood that the process of  FIG. 2  assumes that two-way authentication is required. If only one-way authentication is required, the media  22  is inserted into the component requiring transmission if its configuration information, the configuration information is downloaded onto the media  22 , and then the media  22  is inserted into the other component to download the first component&#39;s configuration information thereto. Similarly, in a simplified implementation, the media  22  may be sold with the server  12  and already have the configuration information of the server  12  stored therein, so that the above process may commence at block  40  and skip blocks  36  and  38 .  
      The above logic alternatively may be implemented by configuring the removable media  22  as a near field card such as a “Smart Card” and using near field principles known in the art to transfer configuration information using the card.  
       FIG. 3  shows one implementation of how the secondary communication systems  18 ,  28  are used to exchange configuration information. If the secondary communication systems are IR systems having respective IR ports such as IR remote control ports that are found on many devices, the logic of  FIG. 3  commences at block  46 , wherein the server  12  and component  24  are positioned in line of sight (LOS) of each other, with their IR ports aligned with each other as necessary to achieve communication therebetween. At block  48 , the necessary configuration information is transferred between the devices over the secondary communication systems  18 ,  28 . Alternatively, the remote control device  19  can be used as a mobile relay node with storage between the server  12  and component  24  if LOS and/or IR port alignment is not feasible.  
      In an alternate embodiment the secondary communication system may be a near-field communication system in accordance with principles discussed above. A non-limiting example of a near field communication system is disclosed in U.S. Pat. No. 6,121,933, incorporated herein by reference. In such an embodiment the step at block  46  is accomplished by moving the server  12  and component  24  close together, to within the communication distance of the secondary system. The configuration information is automatically exchanged at block  48  once the server  12 /component  24  detect the other within its near field. Or, instead of automatic exchange, to initiate transfer of configuration information the user may be required to depress one or both of the buttons  23  (server) or  34  (component).  
      As yet another alternative, the near field system can be implemented by using the body of the person as the link between components. U.S. Pat. No 5,796,827, incorporated herein by reference, discloses one such system. More specifically, the person might be required to simultaneously touch both buttons  23 ,  34  (which can be, e.g., personal area network (PAN) electrodes) to complete the secondary communication system path between the server  12  and component  24 . As is known in the PAN art, the signal path is through the user&#39;s body and the return path is through the near electromagnetic field. While the field may be intercepted by nearby components  24  that are not touched, the electrodes that are touched can indicate which devices are to communicate configuration information with each other.  
       FIG. 4  shows yet another way to transfer configuration information between the server  12  and component  24 . Commencing at block  50 , the server  12  and component  24  are positioned within LOS of each other. At block  52  configuration information is exchanged over the primary communication systems but not yet validated. Proceeding to block  54 , one or both of the server  12  and component  24  determine a value of a special physical parameter of its received signal. This parameter may be a delay spread and/or distribution of signal strengths over receiver antennae. In the case of a received signal spread/distribution, it can be determined at decision diamond  56  whether the spread/distribution has a Rician distribution throughout configuration information transfer and/or whether the signal strengths over the various antennae of each receiving device match legacy distribution/signal strength information for various LOS angles. This information can be obtained from the RF signal prior to equalization.  
      As understood herein, a Rician distribution indicates RF transmission with a dominant LOS component (and, hence, transmission from a legitimate component  24 ). Accordingly, at decision diamond  56  it is essentially determined whether the value of the parameter indicates LOS or other outcome that represents the presence of a legitimate device. If not, “invalid configuration information exchange” is returned at block  58  and the component  24  is denied entry to the home network. On the other hand, if the test at decision diamond  56  is passed, “valid configuration information exchange” is returned at block  60 , and the component  24  is admitted to the network. In a minor variation, the configuration information is exchanged only if the parameter indicates a Rician distribution for received RF signals.  
      Preferably, the allowed delay spread accounts for known scattering in the vicinity of the receiving device. To further promote system integrity, the user may be required to manipulate a button on either or both devices synchronously with configuration information transfer.  
      While the particular SYSTEM AND METHOD FOR AUTHENTICATING COMPONENTS IN WIRELESS HOME ENTERTAINMENT SYSTEM as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular means “at least one”. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for”.  
      We claim: