Abstract:
To provide remote wireless interface with a computer, a fixed base station is coupled to output ports of the host computer and receives computer output signals intended for application to one or more computer output devices, such as a speaker and video display. The base station includes a transceiver that transmits wireless communication signals over a wireless communication link to a portable input/output unit. The portable input/output unit contains a set of input/output devices through which a user may interact with the host computer. It also includes a transceiver which conducts bidirectional wireless communications with the base station via the wireless communication link. As a result output device signals from the computer are transmitted to and drive output devices of the remote unit. In a complementary manner, input device signals associated with a user&#39;s operation of one or more input devices of the portable unit are transmitted to the base station and applied therefrom as inputs to the computer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present application claims the benefit of co-pending U.S. Provisional Patent Application Serial No. 60/175,151, filed Jan. 7, 2000, entitled: “Wireless Remote Computer Interface System,” by T. Reynolds, assigned to the owner of the present application and the disclosure of which is incorporated herein. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates in general to communication systems and components therefor, and is particularly directed to a reduced complexity and relatively compact arrangement, for providing robust, wireless remote and portable input/output interface capability with the full functionality of a computer and associated peripherals, within a practical wireless environment, such as an office, small office/home office, industrial facility and the like.  
         BACKGROUND OF THE INVENTION  
         [0003]    Although the computer industry has enjoyed substantial diversification of its products among a wide variety of customers, including military, industrial, educational, business and household users, there has been very little development of the configuration of the personal computer (PC) workstation, the complexity and size of which may vary over a wide range of variables, including processing power and speed, mass storage, communication capability, etc. The user&#39;s concern is the ability to interact with the workstation, typically by means of one or more input devices, such as a keyboard, pointer (e.g., mouse, joystick), etc, and one or more real time output devices, such as a monitor and a set of speakers.  
           [0004]    Even though such input/devices are simply a means to supply inputs to and receive information from the computer, the fact that they are part of a stationary workstation cluster (typically consisting of a computer, monitor, speakers, keyboard, mouse, and one or more optional peripherals, such as a printer, scanner, wireline or wireless communication devices, etc.), means that the user must be physically located at the workstation cluster in order to use it—thereby constraining user mobility and flexibility.  
         SUMMARY OF THE INVENTION  
         [0005]    In accordance with the present invention, such limitations of a conventional personal computer workstation are effectively obviated by means of a new and improved computer interface system, which is not a computer in and of itself, in the sense of the computer workstation it interfaces, but provides input/output capability in the form of a relatively compact and portable architecture, that provides the user with interactive access to the computer, and thereby to associated mass storage, high bandwidth communications, printing, and other capabilities of a workstation, in an untethered, wireless environment. The invention thus effectively removes mobility limitations on the user in the context of accessing all the functionality of the computer and associated peripherals, by providing the user with robust wireless data networking connectivity substantially anywhere within a practical wireless environment, such as an office, small office/home office, industrial, or outdoor environment.  
           [0006]    For this purpose, the wireless computer interface system of the present invention comprises two components: 1— a fixed wireless base station connected to a host computer; and 2— a portable wireless remote platform, that provides user input/output capability with the computer to which the base station is connected. Namely, the base station provides a bidirectional interface between the remote unit and the host computer. It is interfaced with input/output ports of the computer, and is operative to conduct wireless communications with the wireless remote unit via a wireless communication link that employs an unlicensed portion of the RF spectrum. The remote unit includes one or more input devices, such as a touchpad pointer device and keyboard, through which the user remotely supplies input commands to the computer, as well as one or more output devices, such as a flat panel display and audio speakers, that are driven by output signals sourced by the computer.  
           [0007]    In the output direction from the host computer to an output device of the remote unit, the base station is operative to process audio and video signals into encoded format for transmission as a composite data signal over the wireless communication link. In the input direction to the host computer from an input device on the remote unit, the base station is directly interfaced with pointer device and keyboard input ports of the computer. The base station is operative to provide substitute replications of pointer and keyboard signals the computer would normally expect to see coming from a desktop situated pointer device and the keyboard. For this purpose, the base station is configured to receive and demodulate wireless communication signals transmitted from the remote unit, which contain information representative of user manipulations of associated pointer device and keyboard elements installed in the remote unit.  
           [0008]    In order to provide bidirectional interface functionality between the remote unit and the host computer, the base station includes a set of industry standard PC connection ports that interface respective audio, video, pointer device and keyboard signals with associated ports of the host computer. The audio and video signals are digitized and applied to a digital signal processor (DSP), which performs all supervisory control and signal processing functions of the base station. The DSP multiplexes the audio and video signals into a composite data stream, which is then encoded and compressed for transmission. The compression scheme may be selected from a variety of standard encoding applications, such as motion pictures expert group (MPEG) video encoding, digital television (DTV) encoding. The encoded composite (audio/video) data stream is digitally filtered and applied as a modulated baseband signal to a transmitter, the output of which is coupled to an antenna for RF transmission to the remote unit.  
           [0009]    In the input direction from the remote unit to the computer, multiplexed encoded digitized pointer and keyboard data, as contained in a modulated RF signal received by the base station antenna and downconverted by a receiver unit are supplied to the base station DSP. The composite encoded (pointer/keyboard) signals are demodulated, decoded and demultiplexed by the DSP into pointer and keystroke associated signals for application to pointer device and keyboard ports of the host computer.  
           [0010]    The remote unit comprises a pair of receiver and transmitter units, which respectively employ the same receiver and transmitter functionality as the receiver and transmitter units of the base station. In the input direction to the user, the remote unit&#39;s receiver outputs a multiplexed encoded digitized audio/video data signal to a DSP, which performs all supervisory control and signal processing functions for the remote unit, including negotiating the wireless channel to be used for a communication session with the base station. The composite encoded audio/video signal is demodulated, decoded and demultiplexed by the DSP into respective audio and video channels for application to associated speakers and a display contained in the remote unit.  
           [0011]    In the output direction from the user to the computer, the remote unit&#39;s DSP multiplexes and encodes digitized pointer and keystroke signals supplied from a pointer device (e.g., touchpad, pointer stick) and a keyboard unit of the user interface. The encoded composite (pointer/keystroke) data stream is digitally filtered and applied as a modulated baseband signal to the transmitter for transmission over the wireless link to the base station. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 diagrammatically illustrates a preferred embodiment of the wireless computer interface system of the present invention;  
         [0013]    [0013]FIG. 2 diagrammatically illustrates the architecture of a wireless base station of the wireless computer interface system of FIG. 1;  
         [0014]    [0014]FIG. 3 diagrammatically illustrates a transmitter unit employed in the base station and remote unit of the wireless computer interface system of FIG. 1;  
         [0015]    [0015]FIG. 4 diagrammatically illustrates a receiver unit employed in the base station and remote unit of the wireless computer interface system of FIG. 1;  
         [0016]    [0016]FIG. 5 diagrammatically illustrates the architecture of the remote unit of the wireless computer interface system of FIG. 1; and  
         [0017]    [0017]FIG. 6 is a table of examples of unlicensed wireless communication protocols that may be employed in the system of FIG. 1. 
     
    
     DETAILED DESCRIPTION  
       [0018]    Before describing in detail the new and improved wireless computer interface system of the present invention, it should be observed that the invention resides primarily in modular arrangements of conventional communication circuits and input/output devices and components therefor. In terms of a practical implementation that facilitates their manufacture, these modular arrangements may be readily configured using field programmable gate array (FPGA) and application specific integrated circuit (ASIC) chip sets, and commercially available input/output devices and components. As a consequence, the configurations of these arrangements and the manner in which they are interfaced with the input/output ports of a stand alone computer workstation have been illustrated in readily understandable block diagram format, which shows only those specific details that are pertinent to the present invention, so as not to obscure the disclosure with details that are readily apparent to one skilled in the art having the benefit of present description.  
         [0019]    A non-limiting, but preferred embodiment of the wireless computer interface system of the present invention is diagrammatically illustrated in FIG. 1 as comprising a wireless base station  10  and a (portable) wireless remote input/output unit  20 . The base station  10  (to be described in detail below with reference to FIGS.  2 - 4 ), serves as a bidirectional interface between the remote unit  20  and a host computer  30 . As such the base station is configured to be directly interfaced with input/output ports of the host computer  30  and may be physically installed at the workstation containing the host computer. Regardless of its installed location the base station  10  is operative to conduct wireless communications with the wireless remote unit  20  via a wireless communication link  40 . The remote unit  20  (to be described in detail below with reference to FIG. 5), is configured as a portable input/output device. Via the wireless link  40  with the base station, the remote unit interfaces input commands to the computer supplied by one or more input devices as operated by the user. It also receives output device associated signals from the computer for conveying information to the user via one or more output devices contained in the remote unit.  
         [0020]    For this purpose, in the output direction (from the host computer to an output device), the base station  10  is directly interfaced with a set of audio and video output ports  31  and  32  of the host computer  30 , by means of associated audio and video links  41  and  42 . These links convey supply respective audio and video output signals from the computer that would normally be applied to an associated set of speakers and a display monitor (not shown) installed at the computer workstation. As will be described, the wireless base station  10  is operative to process these audio and video signals into encoded format for transmission as a composite data signal over a wireless communication link  40  to the remote unit  20 .  
         [0021]    In the input direction (to the host computer from an input device on the remote unit), the base station  10  is directly interfaced with a set of pointer device (e.g., mouse, stick, touchpad, and the like) and keyboard input ports  33  and  34  of the host computer  30 , by means of associated mouse and video keyboard links  43  and  44 , over which pointer and keyboard input signals source from a pointer device and a keyboard (not shown) installed at the workstation, would normally be applied to the host computer  30 . In order to provide substitute replications of pointer and keyboard signals the host computer  30  would normally expect to see coming from its associated pointer device and keyboard, the base station  10  is configured to receive and demodulate wireless communication signals, that are transmitted over the wireless communication link  40  from the remote unit  20 , and which contain information representative of user manipulations of associated pointer device and keyboard elements of a set of input devices installed on the remote unit  20 , as will be described.  
         [0022]    Referring now to FIG. 2, the architecture of the wireless base station  10  is diagrammatically illustrated as comprising a host computer interface  100 , which includes a set of industry standard PC connection ports  101 ,  102 ,  103  and  104 , that interface respective audio, video, pointer device and keyboard signals with ports  31 ,  32 ,  33  and  34  of the host computer  30 . As a non-limiting examples, for the output direction, audio port  101  may comprise an industry standard one-eighth inch stereo phono jack with a line level audio output, while video port  102  may comprise an industry standard HD15 SVGA (1024×768×256 color MAX) port. For the input direction, the pointer device port  103  may comprise a standard PS-2 Mouse Interface, and keyboard port  104  may comprise a standard PS-2 Keyboard Interface.  
         [0023]    The host computer interface  100  further includes an audio signal-sampling, analog-to-digital converter (ADC)  105 , which is operative to digitize (sample) the audio signals coupled to the audio port  101  for application over a digital audio link  111  to a digital signal processor (DSP)  120 , which performs all supervisory control and signal processing functions of the base station. Likewise, a video signal-sampling ADC  106  is coupled to digitize the video signals coupled to port  102  for application over a digital video link  112  to the DSP  120 . This and similar digitizing of intermediate frequency (IF) signals for received RF transmissions from the remote terminal (to be described) ensures that all analog signal processing is isolated to the appropriate interface with the DSP  120 , which processes only digitally formatted signals. The digitally formatted pointer and keyboard associated signals as recovered by the DSP  120  from a transmission received from the remote unit are supplied to the host computer interface  100  by digital links  113  and  114 , respectively.  
         [0024]    In the output direction (to the remote unit  20 ), digitized audio and video information supplied over links  111  and  112  from the host computer interface  100  are multiplexed into a composite data stream and then encoded. In order to provide full fidelity and resolution of the video signal for display on an associated video display contained in the remote unit, the video “dot rate” may be computed using standard display processing practice as follows. Dot rate=(horizontal resolution)×(vertical resolution)×(refresh rate)/(retrace rate). For a 1024×768 pixel screen at 60 Hz (non-interlaced) refresh rate, and a 0.8 retrace rate, the dot rate is 58.98 MHz. However, if the color palette provides full (RGB 24-bit) encoding resolution, then the effective RGB full screen rate is 24 times the clock rate (here 58.98 MHz) or approximately 1.42 Gbps. If the color palette is limited to only eight bits (256 colors), then the effective RGB full screen rate is still a very large 472 Mbps. Thus in either case the video signal must be compressed prior to wireless transmission.  
         [0025]    The video compression scheme may be selected from a variety of standard encoding applications, such as motion pictures expert group (MPEG) video encoding, which is an ISO standard (ISO/IEC 13818-1) and commonly employed by satellite broadcast TV providers, and digital television (DTV) encoding. The resulting DTV composite payload consisting of video, audio, control and ancillary channel data has a composite data rate of 19.28 Mbps, which is well below the uncompressed eight bit color 1024×768 screen rate of 472 Mbps of the present example. Using the eight vestigial sideband (8-VSB) modulation of the DTV standard, the 19.28 Mbps compressed video/audio payload may be transmitted over a 6 MHz channel bandwidth. When using DTV compression, its physical and link layer protocols may be replaced with those employed for local area networks (LANs), which are more cost effective and robust in a multi-user environment.  
         [0026]    The encoded composite (audio/video) data stream is digitally filtered by a digital baseband shaping filter within the DSP  120  and applied as a modulated baseband signal over a data link  121  to a transmitter  130  (to be described with reference FIG. 3) of a remote unit interface (RUI)  150 . The transmitter  130  also receives transmission channel control signals from the DSP  120  over a channel control link  122 . The output of the transmitter  130  is coupled to an antenna  160  for RF transmission to remote unit  20 .  
         [0027]    For the input direction (from the remote unit  20  to the computer  10 ), multiplexed encoded digitized pointer and keyboard data, is received by the antenna  160  and coupled to a receiver unit  140  (shown in FIG. 4, to be described) of the RUI  150 , and supplied to the DSP  120  over a link  123 . Receiver channel control signals are coupled from the DSP  120  to the receiver unit  140  over a control channel link  124 . The composite encoded pointer and keyboard signal is demodulated, decoded and demultiplexed by the DSP  120  into pointer and keystroke associated signals over respective links  113  and  114  to the host computer interface  100 .  
         [0028]    The transmitter unit  130  of the RUI  150  is diagrammatically illustrated in FIG. 3 as comprising a digital-to-analog converter (DAC)  301 , which is coupled to convert the encoded composite digitized audio/video signals supplied from the DSP  120  over link  121  into analog format for application to an intermediate frequency (IF) filter  303 . The output of IF filter  303  is coupled to a first input  311  of an up-converting mixer  310 . Mixer  310  has a second input  312  coupled to a numerically controlled oscillator (NCO)  320 . The frequency of the NCO  320  is controlled by the DSP  120  via the transmitter control channel link  122 . Mixer  310  outputs an up-converted radio frequency (RF) output signal to an automatic gain control (AGC) circuit  315 , which is also coupled to receive a gain adjustment command signal supplied over the transmitter control channel link  122  from the DSP  120 , for adjusting the output power level of the transmitted signal. The output of the AGC circuit  315  is coupled to the antenna  160  for wireless transmission to the remote unit. For the non-limiting example of employing a communication frequency of 2.4 GHz (the wavelength of which is on the order of five inches), antenna  160  may be configured as a quarter-wavelength antenna approximately one and one-quarter inches in length, providing an efficient antenna without unduly constraining mechanical design.  
         [0029]    As described briefly above, the wireless communication link preferably uses an FCC “unlicensed” portion of the communication spectrum, such as the 2.4 GHz band, employing frequency hopping or direct sequence spread spectrum modulation formats, or the 5.0 GHz band utilizing orthogonal frequency division multiplexing (OFDM) or GMSK modulation. As a non-limiting example, the wireless protocol employed for the wireless communication channel  40  may comprise the IEEE 802.11 HS (high speed) standard using OFDM supporting data rates up to 54 Mbps, or the European developed Hyper LAN (aka Broadband Radio Access Networks or BRAN) standard supporting data rates of 24 Mbps using GMSK. These and other non-limiting examples of wireless communication protocols tabulated in FIG. 6 provide for robust high-speed wireless data networking connectivity in office, small office/home office, industrial and outdoor environments.  
         [0030]    The receiver unit  140  of the RUI  150  is diagrammatically illustrated in FIG. 4 as comprising a bandpass filter  401 , which is coupled to filter the output of antenna  160 , to improve the sensitivity and dynamic range of the signal received from the remote unit  20 . The filtered output by the bandpass filter  401  is coupled to an AGC circuit  403 , the output of which is coupled to a first input  411  of a down-converting IF mixer  410 . A second input  412  of the IF mixer  410  is coupled to the output of an NCO  420 , the frequency of which is controlled by the DSP  120  via receiver control channel link  124 . The IF mixer  410  outputs a down-converted IF signal to an automatic level control circuit  415 , which serves to ensure a uniform signal amplitude for application to an ADC  417 . The ADC  417  outputs a digitized IF signal containing the modulated pointer/keystroke data to the digital link  123  for application to the DSP  120 .  
         [0031]    [0031]FIG. 5 diagrammatically illustrates the architecture of the remote unit  20  as comprising a receiver unit  510 , which employs the same receiver functionality as the receiver unit  140  of the base station  10 , described above with reference to FIG. 4. Namely, in the input direction (to the user) the receiver unit  510  is coupled to the output of an antenna  512 , which is configured to detect the RF transmission (e.g., at 2.4 GHz) from the base station  10 , and outputs a multiplexed encoded digitized audio/video data signal to a DSP  520  over a received data link  514 . As in the base station  10 , the DSP  520  performs all supervisory control and signal processing functions for the remote unit  20 . This includes establishing the wireless link  40  by negotiating the wireless channel to be used for a communication session, using standard wireless channel establishment procedures. Receiver channel control signals are coupled from the DSP  520  to the receiver unit  510  over a receiver channel control link  516 . The composite encoded audio/video signal is demodulated, decoded and demultiplexed by the DSP  520  into respective audio and video channels for application to an output bus  532  to which respective speaker and display units  535  and  536  of a user interface  530  are coupled. The remote units user interface  530  may employ the same set of industry standard PC input/output connection ports employed by the host computer interface  100  of the wireless base station  10 , described above.  
         [0032]    In the output direction (from the user), the DSP  520  is coupled to multiplex and encode digitized pointer and keystroke signals supplied from an input bus portion  534  of the user interface  530  into a composite (pointer/keystroke) data stream. Input bus portion  534  is coupled to receive respective pointer movement signals from a pointer device (e.g., touchpad, pointer stick)  550  and keystroke signals from a keyboard unit  560  of the user interface  530 . The encoded composite (pointer/keystroke) data stream is digitally filtered by a digital baseband shaping filter within the DSP  520  and applied as a modulated baseband signal over a transmission data link  517  to a transmitter  540 . Like remote unit receiver unit  510 , which is configured to perform the same functionality as the receiver  140  in the base station  10 , the remote unit&#39;s transmitter  540  employs the same transmitter functionality as the transmitter  130  in the base station  10 . The transmitter  540  receives transmission channel control signals over a transmission data link  518 . The output of the transmitter  540  is coupled to the antenna  512  for transmission to the base station  10 .  
         [0033]    As will be appreciated from the foregoing description, the wireless computer input/output interface system of the present invention effectively obviates user location limitations imposed by a conventional personal computer workstation, so that the user may have mobile interactive access with the computer, and its associated mass storage, high bandwidth communications, printing, and other capabilities of a workstation or server substantially anywhere within a practical wireless environment, such as an office, small office/home office, industrial, or outdoor environment.  
         [0034]    As a non-limiting example of a ‘household’ setting, the invention allows a consumer ready access to an office or den-located computer from a relatively remote location, such as kitchen, patio, garage, bedroom, etc., thereby facilitating access to the internet, word processing application, games, etc. In a mobile environment, such as an automobile, wireless connectivity with GPS capability allows the mobile computer (CPU) to be installed in an “out of the way” location in the vehicle. The invention is thereby capable of providing any of a variety of computer related functions, such as access to information, real time tracking, communications, the ability to play games, and access the internet from inside the vehicle.  
         [0035]    In a business environment, the invention may be used in any office, where connectivity of a computer connected to a corporate network, printer and internet access, is required, while also providing a light weight terminal to view information. Similarly, the invention may be readily employed in a teaching or training application, where multiple terminals are used in a read-only manner, in order to send information to a number of private screens where overhead displays are in appropriate, such in a judicial, medical, or military application.  
         [0036]    While I have shown and described an embodiment in accordance with the present invention, it is to be understood that the same is not limited thereto but is susceptible to numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are obvious to one of ordinary skill in the art.