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:
TECHNICAL FIELD 
       [0001]    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 TV receivers for indoor and mobile users. 
       BACKGROUND 
       [0002]    Traditionally, terrestrial ATSC HDTV programming can only be viewed on a TV console in a fixed or static environment (e.g. family room). 
         [0003]    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. 
         [0004]    The new updated ATSC standard for ATSC Mobile/Handheld is called ATSC A153. This standard will address the Doppler interference issue only for low-resolution display devices. The ATSC A153 system is described in  FIG. 3 . 
         [0005]    However, for high definition/high resolution TV reception, 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; U.S. patent application Ser. No. 13/872,917 entitled MULTIPLE ANTENNA ATSC HDTV RECEIVER DEVICE, by Yang; U.S. patent application Ser. No. 13/889,158 entitled A METHOD OF CHANNEL CHARACTERIZATION FOR MOBILE ATSC HDTV RECEIVER, 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 ATSC Legacy System Field Sync Symbol and ATSC Mobile / Handheld System Known Symbol Extractor and the function of the Channel State Information Prediction Kalman Filter. 
       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 ATSC MH Stream Assisted Channel State Information Estimator &amp; Signal-To-Noise Ratio Estimator. 
           [0013]      FIG. 3  shows the ATSC A153 Terrestrial TV System. 
           [0014]      FIG. 4  shows a single antenna being coupled to a single tuner. 
           [0015]      FIG. 5  shows a single antenna being coupled to a plurality of tuners. 
           [0016]      FIG. 6  shows a plurality of antennas being coupled to a plurality of tuners. 
           [0017]      FIG. 7  shows a single Wi-Fi ATSC TV antenna. 
           [0018]      FIG. 8  shows a plurality of Wi-Fi ATSC Antennas. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    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 
       [0020]      100 —Terrestrial ATSC TV Receiver (an example) 
         [0021]      101 —Digital ATSC IF Signal 
         [0022]      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 
         [0023]      103 —Synchronized baseband ATSC TV signal 
         [0024]      104 —Decision Feedback Equalizer 
         [0025]      105 —Demodulated ATSC TV Signal 
         [0026]      106 —Forward Error Correction (FEC) Block: includes Viterbi Decoder, De-interleaver, R.S. Decoder, and De-randomizer 
         [0027]      107 —MPEG TS (Transport Stream) 
         [0028]      108 —Channel State Information Estimator &amp; SNR (Signal-To-Noise Ratio) Estimator 
         [0029]      109 —Channel State Information 
         [0030]      110 —Channel State Information Assisted Equalizer 
         [0031]      111 —Decoded ATSC TV Signal 
       FIGS.  2 — 108   
       [0032]      201  (also  103  in FIG.  1 )—Synchronized baseband ATSC TV signal 
         [0033]      202  (also  111  in FIG.  1 )—Decoded ATSC TV Signal 
         [0034]      203 —Time Domain Iterative Channel Impulse Response Estimator &amp; SNR Estimator 
         [0035]      204 —Initial Channel Impulse Response 
         [0036]      205 —Frequency Domain Iterative Channel Frequency Response Estimator 
         [0037]      206 —Channel Impulse Response and SNR 
         [0038]      207 —Channel Impulse Response 
         [0039]      208 —Weighted Combining Unit for Channel Impulse Response 
         [0040]      209 —Weighted Channel Impulse Response and SNR 
         [0041]      210 —ATSC Legacy System Field Sync Symbol and ATSC Mobile/Handheld System Known Symbol Extractor 
         [0042]      211 —ATSC Legacy System Field Sync and ATSC Mobile/Handheld System Known Symbol 
         [0043]      212 —Kalman Filter 
         [0044]      213 —(also  109  in FIG.  1 )—Channel State Information 
       FIG.  3 —PRIOR ART—ATSC A153 Terrestrial TV System 
       [0045]      301 —ATSC Legacy System 
         [0046]      302 —ATSC Mobile/Handheld System 
         [0047]      303 —MPEG 2 Transport 
         [0048]      304 —IP Transport 
         [0049]      305 —M/H Framing 
         [0050]      306 —RF/Transmission System 
       FIG. 4 
       [0051]      401 —TV Antenna 
         [0052]      402 —Wired Connection 
         [0053]      403 —TV Tuner 
         [0054]      404  (also  101  in FIG.  1 )—Digital ATSC IF Signal 
         [0055]      405  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block 
       FIG. 5 
       [0056]      501 —TV Antenna 
         [0057]      502 —Wired Connection 
         [0058]      503 —TV Tuner 
         [0059]      504  (also  101  in FIG.  1 )—Digital ATSC IF Signal 
         [0060]      505  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block 
       FIG. 6 
       [0061]      601 —TV Antenna 
         [0062]      602 —Wired Connection 
         [0063]      603 —TV Tuner 
         [0064]      604  (also  101  in FIG.  1 )—Digital ATSC IF Signal 
         [0065]      605  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block 
       FIG. 7 
       [0066]      701 —Wi-Fi ATSC TV Antenna 
         [0067]      702 —Wi-Fi Connection 
         [0068]      703 —TV Tuner 
         [0069]      704  (also  101  in FIG.  1 )—Digital ATSC IF Signal 
         [0070]      705  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block 
       FIG. 8 
       [0071]      801 —Wi-Fi ATSC TV Antenna 
         [0072]      802 —Wi-Fi Connection 
         [0073]      803 —TV Tuner 
         [0074]      804  (also  101  in FIG.  1 )—Digital ATSC IF Signal 
         [0075]      805  (also  100 B in FIG.  1 )—ATSC HDTV receiver functional block 
         [0076]      FIG. 1(A)  is an example of a traditional ATSC TV receiver functional block diagram. 
         [0077]    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. 
         [0078]    The output of functional block ( 102 ) is a synchronized baseband ATSC TV signal ( 103 ), which goes in to a decision feedback equalizer ( 104 ). The demodulated ATSC TV 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 ). 
         [0079]      FIG. 1(B)  is an example of a new ATSC TV receiver functional block diagram applying this invention. 
         [0080]    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 ). 
         [0081]    The channel state information ( 109 ) is generated from the Channel State Information Estimator &amp; SNR Estimator ( 108 ) based on the synchronized baseband ATSC TV signal ( 103 ) and the decoded ATSC HDTV signal ( 111 ). 
         [0082]      FIG. 2  is the ATSC MH Stream Assisted Channel State Information Estimator &amp; Signal-To-Noise Ratio Estimator. 
         [0083]    The ATSC field-sync sequence of the ATSC Legacy System signal and the known symbol of the ATSC Mobile/Handheld System ( 211 ) are extracted by the ATSC Legacy System Field Sync Symbol and ATSC Mobile/Handheld System Known Symbol Extractor ( 210 ) from the Synchronized baseband ATSC TV signal ( 201 ). 
         [0084]    The ATSC field-sync sequence of the ATSC Legacy System signal and the known symbol of the ATSC Mobile/Handheld System ( 211 ) and the decoded ATSC TV signal ( 202 ) go 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 TV reception environment, a decoded ATSC TV signal ( 203 ) must be used in between the field sync signals in ( 201 ). 
         [0085]    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 ). 
         [0086]    The output of  208 , the Weighted Channel Impulse Response and SNR ( 209 ), goes to the Kalman Filter ( 212 ), which predicts the current channel state information by using the statistics of the past dynamic channel state information. 
         [0087]    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 ). 
         [0088]    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 TV 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       
 
         [0092]    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 ). 
         [0093]    The output of  208 , the Weighted Channel Impulse Response and SNR ( 209 ), goes to the Kalman Filter ( 212 ), which predicts the current channel state information by using the statistics of the past dynamic channel state information. 
         [0094]    The output of the Kalman Filter ( 212 ) is the channel state information ( 213 ), which is a combined channel impulse response and SNR for each signal segment. 
         [0095]    FIG.  3 —PRIOR ART—shows a reference system for the ATSC A153 Terrestrial TV Broadcasting Standard. 
         [0096]      FIG. 4  shows a single antenna being coupled to a single tuner. A single TV Antenna ( 401 ) connects to a single TV Tuner ( 403 ) by a wired connection ( 402 ). The TV Tuner ( 403 ) outputs a Digital ATSC IF Signal ( 404 ) to the ATSC HDTV receiver functional block ( 405 ). 
         [0097]      FIG. 5  shows a single antenna being coupled to a plurality of tuners. A single TV Antenna ( 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 ). 
         [0098]      FIG. 6  shows a plurality of antennas being coupled to a plurality of tuners. A plurality of TV Antennas ( 601 ) connects to a plurality of TV Tuners ( 603 ) by wired connections ( 602 ). The TV Tuner ( 603 ) outputs a Digital ATSC IF Signal ( 604 ) to the ATSC HDTV receiver functional block ( 605 ). 
         [0099]      FIG. 7  shows a single Wi-Fi ATSC TV antenna. The Wi-Fi ATSC TV Antenna ( 701 ) is connected to the TV Tuner ( 703 ) using a Wi-Fi connection ( 702 ). The TV Tuner ( 703 ) outputs a Digital ATSC IF Signal ( 704 ) to the ATSC HDTV receiver functional block ( 705 ). 
         [0100]      FIG. 8  shows a Plurality Wi-Fi ATSC Antennas. A plurality of Wi-Fi ATSC TV Antennas ( 801 ) is connected to a plurality of TV Tuners ( 803 ) using Wi-Fi connections ( 802 ). The TV Tuner ( 803 ) outputs a Digital ATSC IF Signal ( 804 ) to the ATSC HDTV receiver functional block ( 805 ).