US2011255622A1PendingUtilityA1

Methods and apparatus for reduction of a peak to average ratio for an ofdm transmit signal

47
Assignee: QUALCOMM INCPriority: Apr 4, 2006Filed: Jun 24, 2011Published: Oct 20, 2011
Est. expiryApr 4, 2026(expired)· nominal 20-yr term from priority
Inventors:Durk L. Van VeenFuyun LingRaghuraman Krishnamoorthi
H04L 27/2614H04L 27/2615H04L 25/03866
47
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Claims

Abstract

Methods and apparatus for reduction of a peak to average ratio for an OFDM transmit signal. In an aspect, a method is provided for reducing a peak to average ratio of a transmit waveform. The method includes obtaining a primary scrambler sequence, generating a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining the primary and secondary scrambler sequences to produce a PAR reduction sequence. In another aspect, an apparatus is provided for reducing a peak to average ratio of a transmit waveform. The apparatus includes a secondary generator configured to generate a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining logic configured to combine a primary scrambler sequence and the secondary scrambler sequences to produce a PAR reduction sequence.

Claims

exact text as granted — not AI-modified
1 . A method for reducing a peak to average ratio (PAR) of a transmit waveform, the method comprising:
 obtaining a primary scrambler sequence;   generating a secondary scrambler sequence having a length characteristic based on data to be scrambled; and   combining the primary and secondary scrambler sequences to produce a PAR reduction sequence.   
     
     
         2 . The method of  claim 1 , wherein said generating comprises generating the secondary scrambler sequence from a table. 
     
     
         3 . The method of  claim 1 , wherein said generating comprises generating the secondary scrambler sequence from a linear feedback shift register. 
     
     
         4 . The method of  claim 1 , wherein said generating comprises generating the secondary scrambler sequence to have a length based on an amount of data to be transmitted in one symbol. 
     
     
         5 . The method of  claim 1 , wherein said combining comprises performing an exclusive-OR operation to combine the primary scrambler sequence and the secondary scrambler sequence. 
     
     
         6 . The method of  claim 1 , wherein said combining comprises selectively combining the primary scrambler sequence and the secondary scrambler sequence when it is determined that data to be scrambled is zero. 
     
     
         7 . The method of  claim 1 , further comprising combining the PAR reduction sequence and data to produce the transmit waveform. 
     
     
         8 . An apparatus for reducing a peak to average ratio (PAR) of a transmit waveform, the apparatus comprising:
 a secondary generator configured to generate a secondary scrambler sequence having a length characteristic based on data to be scrambled; and   combining logic configured to combine a primary scrambler sequence and the secondary scrambler sequences to produce a PAR reduction sequence,   
     
     
         9 . The apparatus of  claim 8 , wherein said secondary generator is configured to generate the secondary scrambler sequence from a table. 
     
     
         10 . The apparatus of  claim 8 , wherein said secondary generator is configured to generate the secondary scrambler sequence from a linear feedback shift register. 
     
     
         11 . The apparatus of  claim 8 , wherein said secondary generator is configured to generate the secondary scrambler sequence to have a length based on an amount of data to be transmitted in one symbol. 
     
     
         12 . The apparatus of  claim 8 , wherein said combining logic is configured to perform an exclusive-OR operation to combine the primary scrambler sequence and the secondary scrambler sequence. 
     
     
         13 . The apparatus of  claim 8 , wherein said combining logic is configured to selectively combine the primary scrambler sequence and the secondary scrambler sequence when it is determined that data to be scrambled is zero. 
     
     
         14 . The apparatus of  claim 8 , further comprising second combining logic configured to combine the PAR reduction sequence and data to produce the transmit waveform. 
     
     
         15 . An apparatus for reducing a peak to average ratio (PAR) of a transmit waveform, the apparatus comprising:
 means for obtaining a primary scrambler sequence;   means for generating a secondary scrambler sequence having a length characteristic based on data to be scrambled; and   means for combining the primary and secondary scrambler sequences to produce a PAR reduction sequence.   
     
     
         16 . The apparatus of  claim 15 , wherein said means for generating comprises means for generating the secondary scrambler sequence from a table. 
     
     
         17 . The apparatus of  claim 15 , wherein said means for generating comprises means for generating the secondary scrambler sequence from a linear feedback shift register. 
     
     
         18 . The apparatus of  claim 15 , wherein said means for generating comprises means for generating the secondary scrambler sequence to have a length based on an amount of data to be transmitted in one symbol. 
     
     
         19 . The apparatus of  claim 15 , wherein said means for combining comprises means for performing an exclusive-OR operation to combine the primary scrambler sequence and the secondary scrambler sequence. 
     
     
         20 . The apparatus of  claim 15 , wherein said means for combining comprises means for selectively combining the primary scrambler sequence and the secondary scrambler sequence when it is determined that data to be scrambled is zero. 
     
     
         21 . The apparatus of  claim 15 , further comprising means for combining the PAR reduction sequence and data to produce the transmit waveform. 
     
     
         22 . A computer-readable medium having a computer program comprising instructions, which when executed by at least one processor, operate to reduce a peak to average ratio (PAR) of a transmit waveform, the computer program comprising:
 instructions for obtaining a primary scrambler sequence;   instructions for generating a secondary scrambler sequence having a length characteristic based on data to be scrambled; and   instructions for combining the primary and secondary scrambler sequences to produce a PAR reduction sequence.   
     
     
         23 . The computer program of  claim 22 , wherein said instructions for generating comprise instructions for generating the secondary scrambler sequence from a table. 
     
     
         24 . The computer program of  claim 22 , wherein said instructions for generating comprise instructions for generating the secondary scrambler sequence from a linear feedback shift register. 
     
     
         25 . The computer program of  claim 22 , wherein said instructions for generating comprise instructions for generating the secondary scrambler sequence to have a length based on an amount of data to be transmitted in one symbol. 
     
     
         26 . The computer program of  claim 22 , wherein said instructions for combining comprise instructions for performing an exclusive-OR operation to combine the primary scrambler sequence and the secondary scrambler sequence. 
     
     
         27 . The computer program of  claim 22 , wherein said instructions for combining comprise instructions for selectively combining the primary scrambler sequence and the secondary scrambler sequence when it is determined that data to be scrambled is zero. 
     
     
         28 . The computer program of  claim 22 , further comprising instructions for combining the PAR reduction sequence and data to produce the transmit waveform. 
     
     
         29 . At least one processor configured to perform a method for reducing a peak to average ratio (PAR) of a transmit waveform, the method comprising:
 obtaining a primary scrambler sequence;   generating a secondary scrambler sequence having a length characteristic based on data to be scrambled; and   combining the primary and secondary scrambler sequences to produce a PAR reduction sequence.   
     
     
         30 . The method of  claim 29 , wherein said generating comprises generating the secondary scrambler sequence from a table. 
     
     
         31 . The method of  claim 29 , wherein said generating comprises generating the secondary scrambler sequence from a linear feedback shift register. 
     
     
         32 . The method of  claim 29 , wherein said generating comprises generating the secondary scrambler sequence to have a length based on an amount of data to be transmitted in one symbol. 
     
     
         33 . The method of  claim 29 , wherein said combining comprises performing an exclusive-OR, operation to combine the primary scrambler sequence and the secondary scrambler sequence. 
     
     
         34 . The method of  claim 29 , wherein said combining comprises selectively combining the primary scrambler sequence and the secondary scrambler sequence when it is determined that data to be scrambled is zero. 
     
     
         35 . The method of  claim 29 , further comprising combining the PAR reduction sequence and data to produce the transmit waveform.

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