Abstract:
This invention is a method to quickly characterize the time variant channel state information to enable ATSC HDTV signal reception in a mobile environment (e.g. in a moving car, walking, on a bus, etc.) by removing the Doppler interference. The invention relates to a single or multiple antenna ATSC terrestrial DTV receiver for indoor and mobile users.

Description:
[0001]    This application claims the benefit of the U.S. Provisional application No. 61/808,484, filed Apr. 4, 2013. 
     
    
     TECHNICAL FIELD  
       [0002]    The present invention relates generally to an application in a digital television system, more specifically the present invention relates to a single or multiple antenna ATSC terrestrial DTV receivers for indoor and mobile users. 
       BACKGROUND  
       [0003]    Traditionally, terrestrial ATSC HDTV programming can only be viewed on a TV console in a fixed or static environment (e.g. family room). 
         [0004]    Today, mobile devices with screens are ubiquitous. Examples include, but are not limited to; laptops, tablets, cell phones, car infotainment systems, etc. However, terrestrial ATSC HDTV programming cannot be viewed on these devices in a mobile environment. This is because existing ATSC HDTV receivers cannot have stable reception in a mobile environment due to the Doppler interference caused by mobile conditions. 
         [0005]    In order to remove the Doppler interference caused by mobile conditions, a method to quickly estimate the terrestrial ATSC HDTV transmission channel characteristics is needed. 
         [0006]    The following patents are herein incorporated by reference: U.S. patent application Ser. No. 12/512,901 entitled A NOVEL EQUALIZER FOR SINGLE CARRIER TERRESTRIAL DTV RECEIVER, by Yang; U.S. patent application Ser. No. 12/554,925 entitled A MULTIPLE TUNER ATSC TERRESTRIAL RECEIVER FOR INDOOR &amp; MOBILE USERS, by Yang; U.S. patent application Ser. No. 12/572,236 entitled A MULTIPLE TUNER TERRESTRIAL DTV RECEIVER FOR INDOOR &amp; MOBILE USERS, by Yang; U.S. patent application Ser. No. 13/871,869 entitled WI-FI ATSC TV ANTENNA, by Yang; and U.S. patent application Ser. No. 13/872,917 entitled MULTIPLE ANTENNA ATSC HDTV RECEIVER DEVICE, by Yang. 
         [0007]    The prior art made of record and not relied upon are hereupon disclosed: United States patent number 20100273427, by Mergen, which discloses a method and apparatus for filtering noisy estimates to reduce estimation errors; and United States patent number 20130114767, by Lee, which shows an apparatus and method for enhancing channel estimation accuracy in communication systems. 
         [0008]    In addition to the above-referenced applications, the present invention adds the following functions: The function of Time Domain Iterative Channel Impulse Response Estimator &amp; Signal-To-Noise Ratio Estimator, and The function of Weighted Combining Unit for Channel Impulse Response. 
       SUMMARY OF INVENTION  
       [0009]    This invention is a method to quickly estimate the terrestrial ATSC HDTV transmission channel characteristics in order to remove the Doppler interference present in a mobile situation. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS  
         [0010]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
           [0011]      FIG. 1  shows an example of A Terrestrial ATSC HDTV Receiver. 
           [0012]      FIG. 2  shows the Channel State Information Estimator &amp; Signal-To-Noise Ratio Estimator. 
           [0013]      FIG. 3  shows a single antenna being coupled to a single tuner. 
           [0014]      FIG. 4  shows a single antenna being coupled to a plurality of tuners. 
           [0015]      FIG. 5  shows a plurality of antennas being coupled to a plurality of tuners. 
           [0016]      FIG. 6  shows a single Wi-Fi ATSC TV antenna. 
           [0017]      FIG. 7  shows a plurality Wi-Fi ATSC Antennas. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]    The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some examples of the embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
         FIG. 1       100 —Terrestrial ATSC HDTV Receiver (an example)
                 100 (A) shows prior art     100 (B) shows an example of a new ATSC HDTV receiver functional block diagram applying this invention   
                 101 —Digital ATSC IF Signal     102 —IF to Baseband down-conversion and signal synchronization. Includes but not limited to frequency shifting, low-pass filter, symbol timing recovery, carrier recovery, SRRC filter, Field Synchronization, segment synchronization     103 —Synchronized baseband ATSC HDTV signal     104 —Decision Feedback Equalizer     105 —Demodulated ATSC HDTV Signal     106 —Forward Error Correction (FEC) Block: includes Viterbi Decoder, De-interleaver, R.S. Decoder, and De-randomizer     107 —MPEG TS (Transport Stream)     108 —Channel State Information Estimator &amp; SNR (Signal-To-Noise Ratio) Estimator     109 —Channel State Information     110 —Channel State Information Assisted Equalizer     111 —Decoded ATSC HDTV Signal       FIG.  2 — 108 
             201  (also  103  in FIG.  1 )—Synchronized baseband ATSC HDTV signal     202  (also  111  in FIG.  1 )—Decoded ATSC HDTV Signal     203 —Time Domain Iterative Channel Impulse Response Estimator &amp; SNR Estimator     204 —Initial Channel Impulse Response     205 —Frequency Domain Iterative Channel Frequency Response Estimator     206 —Channel Impulse Response and SNR     207 —Channel Impulse Response     208 —Weighted Combining Unit for Channel Impulse Response     209  (also  109  in FIG.  1 )—Channel State Information   
             FIG. 3       301 —TV Antenna     302 —Wired Connection     303 —TV Tuner     304  (also  101  in FIG.  1 )—Digital ATSC IF Signal     305  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block         FIG. 4       401 —TV Antenna     402 —Wired Connection     403 —TV Tuner     404  (also  101  in FIG.  1 )—Digital ATSC IF Signal     405  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block         FIG. 5       501 —TV Antenna     502 —Wired Connection     503 —TV Tuner     504  (also  101  in FIG.  1 )—Digital ATSC IF Signal     505  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block         FIG. 6       601 —Wi-Fi ATSC TV Antenna     602 —Wi-Fi Connection     603 —TV Tuner     604  (also  101  in FIG.  1 )—Digital ATSC IF Signal     605  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block         FIG. 7       701 —Wi-Fi ATSC TV Antenna     702 —Wi-Fi Connection     703 —TV Tuner     704  (also  101  in FIG.  1 )—Digital ATSC IF Signal     705  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block           
 
         [0074]      FIG. 1-100(A) , prior art, is an example of a traditional ATSC HDTV receiver functional block diagram. 
         [0075]    The digital ATSC IF Signal ( 101 ) goes in to the functional block ( 102 ) which performs the following functions: IF to Baseband down-conversion and signal synchronization. Includes but not limited to frequency shifting, low-pass filter, symbol timing recovery, carrier recovery, SRRC filter, Field Synchronization, and segment synchronization. 
         [0076]    The output of functional block ( 102 ) is a synchronized baseband ATSC HDTV signal ( 103 ), which goes in to a decision feedback equalizer ( 104 ). The demodulated ATSC HDTV Signal ( 105 ) from the decision feedback equalizer ( 104 ) goes in to the Forward Error Correction Block ( 106 ), which performs the following functions: Viterbi Decoder, De-interleaver, R.S. Decoder, and De-randomizer, and then generates the MPEG TS ( 107 ). 
         [0077]      FIG. 1-100(B)  is an example of a new ATSC HDTV receiver functional block diagram applying this invention. 
         [0078]    The invention replaces the traditional decision feedback equalizer ( 104 ) in  FIG. 1(A)  with the Channel State Information Estimator &amp; SNR Estimator ( 108 ) and Channel State Information Assisted Equalizer ( 110 ). 
         [0079]    The channel state information ( 109 ) is generated from the Channel State Information Estimator &amp; SNR Estimator ( 108 ) based on the synchronized baseband ATSC HDTV signal ( 103 ) and the decoded ATSC HDTV signal ( 111 ). 
         [0080]      FIG. 2 : 
         [0081]    The ATSC field-sync sequence in the Synchronized baseband ATSC HDTV signal ( 201 ) and the decoded ATSC HDTV signal ( 202 ) goes in to the Time Domain Iterative Channel Impulse Response Estimator in ( 203 ) to initialize and update the channel impulse response ( 204 ). The Time Domain Iterative Channel Impulse Response Estimator in ( 203 ) is using either the Least Means Square (LMS) or the Recursive Least Square (RLS) algorithm. The channel impulse response of ( 209 ) is time variant in mobile environments. Therefore, ( 203 ) is using previously estimated channel impulse response ( 209 ) as a reference to iteratively update the time variant channel impulse response. Because of the time variant nature of the channel impulse response in the mobile ATSC HDTV reception environment, a decoded ATSC HDTV signal ( 203 ) must be used in between the field sync signals in ( 201 ). The output of the Time Domain Iterative Channel Impulse Response Estimator &amp; SNR Estimator ( 203 ) is Channel Impulse Response and SNR ( 206 ), which goes to Weighted Combining of Channel Impulse Response ( 208 ). 
         [0082]    Optionally, in addition to using a Time Domain Iterative Channel Impulse Response Estimator &amp; SNR Estimator ( 203 ), a Frequency Domain Iterative Channel Frequency Response Estimator ( 205 ) can be used, given the initial channel impulse response ( 204 ). 
         [0083]    In the Frequency Domain Iterative Channel Frequency Response Estimator ( 205 ), the following algorithm is used:
       1. Zero padding guard interval data segment reference signal generation   2. Pre-segment and post-segment data removal of the Synchronized baseband ATSC HDTV signal ( 201 ) for each segment   3. Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) are used to do the transformation between channel impulse response and frequency response       
 
         [0087]    The output channel impulse response ( 207 ) is generated from Frequency Domain Iterative Channel Frequency Response Estimator ( 205 ) and fed in to the Weighted Combining Unit for Channel Impulse Response ( 208 ). 
         [0088]    The Weighted Combining Unit for Channel Impulse Response ( 208 ) combines Channel Impulse Response and SNR ( 206 ) and Channel Impulse Response ( 207 ) using a novel weighting algorithm to generate channel state information ( 209 ) which is a combined channel impulse response and SNR for each signal segment. 
         [0089]      FIG. 3  shows a single antenna being coupled to a single tuner. A single TV Antenna ( 301 ) connects to a single TV Tuner ( 303 ) by a wired connection ( 302 ). The TV Tuner ( 303 ) outputs a Digital ATSC IF Signal ( 304 ) to the ATSC HDTV receiver functional block ( 305 ). 
         [0090]      FIG. 4  shows a single antenna being coupled to a plurality of tuners. A single TV Antenna ( 401 ) connects to a plurality of TV Tuners ( 403 ) by wired connections ( 402 ). The TV Tuner ( 403 ) outputs a Digital ATSC IF Signal ( 404 ) to the ATSC HDTV receiver functional block ( 405 ). 
         [0091]      FIG. 5  shows a plurality of antennas being coupled to a plurality of tuners. A plurality of TV Antennas ( 501 ) connects to a plurality of TV Tuners ( 503 ) by wired connections ( 502 ). The TV Tuner ( 503 ) outputs a Digital ATSC IF Signal ( 504 ) to the ATSC HDTV receiver functional block ( 505 ). 
         [0092]      FIG. 6  shows a single Wi-Fi ATSC TV antenna. The Wi-Fi ATSC TV Antenna ( 601 ) is connected to the TV Tuner ( 603 ) using a Wi-Fi connection ( 602 ). The TV Tuner ( 603 ) outputs a Digital ATSC IF Signal ( 604 ) to the ATSC HDTV receiver functional block ( 605 ). 
         [0093]      FIG. 7  shows a Plurality Wi-Fi ATSC Antennas. A plurality of Wi-Fi ATSC TV Antennas ( 601 ) is connected to a plurality of TV Tuners ( 603 ) using Wi-Fi connections ( 602 ). The TV Tuner ( 603 ) outputs a Digital ATSC IF Signal ( 604 ) to the ATSC HDTV receiver functional block ( 605 ).