Methods and apparatus for synchronization of data frames

Abstract

In accordance with an example embodiment of the present invention, a first bit sequence of a first length is assigned to a first group of signaling bits. Further, a second bit sequence of a second length is assigned to a second group of signaling bits. The first bit sequence is scrambled with a first scrambling sequence, and the second bit sequence is scrambled with a second scrambling sequence different from the first scrambling sequence. A first and a second orthogonal frequency-division multiplexing (OFDM) symbol are assigned to the first and the second scrambled bit sequences respectively, and the first and second orthogonal frequency-division multiplexing (OFDM) symbols are transmitted as synchronization symbols of a data frame. Further, a corresponding method for receiving the data frame, and apparatuses for transmission and reception are disclosed.

What is claimed is: 
     
       1. A method comprising:
 assigning a first bit sequence of a first length to a first group of signaling bits information; 
 generating a first scrambling sequence and scrambling the first bit sequence with the first scrambling sequence; 
 assigning a first orthogonal frequency division multiplexing symbol to the first scrambled bit sequence scrambled by the first scrambling sequence; and 
 transmitting the first orthogonal frequency division multiplexing symbol as a synchronization symbol of a data frame, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol, wherein the second orthogonal frequency division multiplexing symbol comprises is assigned to a second bit sequence scrambled by a second scrambling sequence and, wherein the second sequence is assigned to a second group of the signaling bits information, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudo random binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       2. The method according to of  claim 1 , wherein the second group of signaling bits sequence comprises information different from the first group of signaling bits sequence. 
     
     
       3. The method according to of  claim 1 , wherein the data frame is a data frame of a digital video broadcast. 
     
     
       4. A method comprising:
 receiving an orthogonal frequency division multiplexing signal comprising a first orthogonal frequency division multiplexing symbol; 
 synchronizing a data frame based at least in part on the first orthogonal frequency division multiplexing symbol, wherein the first orthogonal frequency division multiplexing symbol corresponds to a first scrambled bit sequence; 
 generating a first sequence by descrambling the first scrambled bit sequence with a first scrambling sequence; and 
 decoding a first group of signaling bits information from the first descrambled bit sequence, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol; 
 determining from the first group of signaling bits orthogonal frequency division multiplexing symbol whether the second orthogonal frequency division multiplexing synchronization symbol is present, and 
 in response to determining that the second orthogonal frequency division multiplexing synchronization symbol is present: 
 receiving the second orthogonal frequency division multiplexing synchronization symbol corresponding to a second scrambled bit sequence; 
 generating a second sequence by descrambling the second scrambled bit sequence with a second scrambling sequence; and 
 decoding a second group of the signaling bits information from the second descrambled bit sequence, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       5. The method according to of  claim 4 , wherein the second group of signaling bits sequence comprises information different from the first group of signaling bits sequence. 
     
     
       6. An apparatus, comprising:
 at least one hardware processor; and 
 at least one memory including computer program code, 
 the at least one memory and the computer program code configured to, with the at least one hardware processor, cause the apparatus to perform at least the following: 
 assign a first bit sequence of a first length to a first group of signaling bits information; 
 generate a first scrambling sequence and scramble the first bit sequence with the first scrambling sequence; 
 assign a first orthogonal frequency division multiplexing symbol to the first scrambled bit sequence scrambled by the first scrambling sequence; and 
 transmit the first orthogonal frequency division multiplexing symbol as a synchronization symbol of a data frame, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol, wherein the second orthogonal frequency division multiplexing symbol comprises is assigned to a second bit sequence scrambled by a second scrambling sequence and, wherein the second sequence is assigned to a second group of the signaling bits information, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudo random binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       7. A non-transitory computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with encoded with instructions that when executed by a computer, the computer program code comprising causes an apparatus to:
 code for assigningassign a first bit sequence of a first length to a first group of signaling bits; 
 code for generatinggenerate a first scrambling sequence and code for scramblingscramble the first bit sequence with the first scrambling sequence; 
 code for assigningassign a first orthogonal frequency division multiplexing symbol to the first scrambled bit sequence; and 
 code for transmittingtransmit the first orthogonal frequency division multiplexing symbolssymbol as a synchronization symbol of a data frame, wherein the first group of signaling bits indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol, wherein the second orthogonal frequency division multiplexing symbol comprises a second bit sequence scrambled by a second scrambling sequence and assigned to a second group of signaling bits, wherein the first and second bit sequences have the same length, wherein the first scrambling sequence is generated by a pseudo randompseudorandom binary sequence generator using a first initialization value, and wherein the second scrambling sequence is generated by the pseudorandom binary sequence generator using a second initialization value. 
 
     
     
       8. A non-transitory computer-readable medium encoded with instructions that, when executed by a computer, perform cause an apparatus to:
 assigningassign a first bit sequence of a first length to a first group of signaling bits information; 
 generatinggenerate a first scrambling sequence and scramblingscramble the first bit sequence with the first scrambling sequence; 
 assigningassign a first orthogonal frequency division multiplexing symbol to the first scrambled bit sequence scrambled by the first scrambling sequence; and 
 transmittingtransmit the first and second orthogonal frequency-division frequency division multiplexing symbols symbol as a synchronization symbols symbol of a data frame, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol, wherein the second orthogonal frequency division multiplexing symbol comprises a second bit sequence scrambled by a second scrambling sequence and, wherein the second sequence is assigned to a second group of the signaling bits information, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudo random binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       9. An apparatus, comprising:
 at least one hardware processor; and 
 at least one memory including computer program code, 
 the at least one memory and the computer program code configured to, with the at least one hardware processor, cause the apparatus to perform at least the following: 
 receive an orthogonal frequency-division multiplexing signal comprising a first orthogonal frequency-division frequency division multiplexing symbol; 
 synchronize a data frame based at least in part on the first orthogonal frequency division multiplexing symbol, wherein the first orthogonal frequency division multiplexing symbol corresponds to a first scrambled bit sequence; 
 descramblegenerate a first sequence by descrambling the first scrambled bit sequence with a first scrambling sequence; and 
 decode a first group of signaling bits information from the first descrambled bit sequence, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol; 
 determine from the first group of signaling bits orthogonal frequency division multiplexing symbol whether the second orthogonal frequency division multiplexing synchronization symbol is present, and 
 in response to determining a determination that the second orthogonal frequency division multiplexing synchronization symbol is present: 
 receive the second orthogonal frequency division multiplexing synchronization symbol corresponding to a second scrambled bit sequence; 
 descramblegenerate a second sequence by descrambling the second scrambled bit sequence with a second scrambling sequence; and 
 decode a second group of the signaling bits information from the second descrambled bit sequence, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       10. A computer program product comprising a non-transitory computer-readable medium bearing computer program code embodied therein for use with a computer, the computer program code comprising encoded with instructions that when executed by a computer, cause an apparatus to:
 code for receivingreceive an orthogonal frequency division multiplexing signal comprising a first orthogonal frequency division multiplexing symbol; 
 code for synchronizingsynchronize a data frame based at least in part on the first orthogonal frequency division multiplexing symbolssymbol, wherein the first orthogonal frequency division multiplexing symbol corresponds to a first scrambled bit sequence; 
 code forgenerate a first sequence by descrambling the first scrambled bit sequence with a first scrambling sequence; and 
 code for decoding a first group ofdecode signaling bitsinformation from the first descrambled bit sequence and, wherein the first group of signaling bits orthogonal frequency division multiplexing symbol indicates whether a next symbol comprises a second orthogonal frequency division multiplexing symbol as an additional synchronization symbol; 
 code for determiningdetermine from the first group of signaling bitsorthogonal frequency division multiplexing symbol whether the second orthogonal frequency division multiplexing synchronization symbol is present, and 
 in response to determining a determination that the second orthogonal frequency division multiplexing synchronization symbol is present: 
 code for receivingreceive the second orthogonal frequency division multiplexing synchronization symbol corresponding to a second scrambled bit sequence; 
 code forgenerate a second sequence by descrambling the second scrambled bit sequence with a second scrambling sequence; and 
 code for decoding a second group ofdecode the signaling bitsinformation from the second descrambled bit sequence, wherein the first and the second bit sequences have the same length, and wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein and the second scrambling sequence is generated by the are different parts of a pseudorandom binary sequence generator using a second initialization value having a repetition length greater than each length of the first and the second sequences. 
 
     
     
       11. The method of claim 1, wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein the second scrambling sequence is generated by the pseudorandom binary sequence generator using a second initialization value. 
     
     
       12. The method of claim 1, wherein the second sequence is identical to the first sequence. 
     
     
       13. The method of claim 4, wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein the second scrambling sequence is generated by the pseudorandom binary sequence generator using a second initialization value. 
     
     
       14. The method of claim 4, wherein the second sequence is identical to the first sequence. 
     
     
       15. The method to claim 4, wherein the data frame is a data frame of a digital video broadcast. 
     
     
       16. The apparatus of claim 6, wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein the second scrambling sequence is generated by the pseudorandom binary sequence generator using a second initialization value. 
     
     
       17. The apparatus of claim 6, wherein the second sequence is identical to the first sequence. 
     
     
       18. The apparatus to claim 6, wherein the data frame is a data frame of a digital video broadcast. 
     
     
       19. The apparatus of claim 9, wherein the first scrambling sequence is generated by a pseudorandom binary sequence generator using a first initialization value, and wherein the second scrambling sequence is generated by the pseudorandom binary sequence generator using a second initialization value. 
     
     
       20. The apparatus of claim 9, wherein the second sequence is identical to the first sequence. 
     
     
       21. The apparatus to claim 9, wherein the data frame is a data frame of a digital video broadcast.