Apparatus and method for reducing peak to average power ratio in an orthogonal frequency division multiplexing system
First Claim
1. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, a method of generating the selected masked information bit sequence for transmission to a receiver, the method comprising the steps of:
- generating an information sequence by adding CRC (Cyclic Redundancy Code) bits to an information bit stream, the CRC bits being used for error check;
generating a plurality of masked information sequences by masking the information sequence with a plurality of different mask sequences;
generating IFFT (Inverse Fast Fourier Transform) sequences by inverse-fast-Fourier-transforming the masked information sequences; and
selecting an IFFT sequence having the lowest PAPR among the IFFT sequences.
1 Assignment
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Accused Products
Abstract
An apparatus and method for PAPR reduction in an OFDM system are disclosed. On a transmission side, an information sequence is generated by adding CRC bits to an information bit stream and masked with a plurality of different mask sequences. The masked information sequences are inverse-fast-Fourier-transformed. An IFFT sequence having the lowest PAPR is selected among the IFFT sequences.
37 Citations
29 Claims
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1. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, a method of generating the selected masked information bit sequence for transmission to a receiver, the method comprising the steps of:
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generating an information sequence by adding CRC (Cyclic Redundancy Code) bits to an information bit stream, the CRC bits being used for error check;
generating a plurality of masked information sequences by masking the information sequence with a plurality of different mask sequences;
generating IFFT (Inverse Fast Fourier Transform) sequences by inverse-fast-Fourier-transforming the masked information sequences; and
selecting an IFFT sequence having the lowest PAPR among the IFFT sequences. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, an apparatus for generating the selected masked information bit sequence for transmission to a receiver, the apparatus comprising:
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a CRC (Cyclic Redundancy Code) generator for generating an information sequence by adding CRC bits to an information bit stream, the CRC bits being used for error check;
a plurality of maskers for generating a plurality of masked information sequences by masking the information sequence with a plurality of different mask sequences;
an IFFT (Inverse Fast Fourier Transformer) for generating IFFT sequences by inverse-fast-Fourier-transforming the masked information sequences; and
a selector for selecting an IFFT sequence having the lowest PAPR among the IFFT sequences. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, a method of determining the selected masked information bit sequence received from a transmitter, the method comprising the steps of:
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generating an FFT (Fast Fourier Transform) sequence by fast-Fourier-transforming a received masked information sequence;
masking the FFT sequence with a plurality of different mask sequences used by a transmitter;
checking errors using CRC (Cyclic Redundancy Code) bits of each of the masked information sequences; and
detecting a mask sequence selected by the transmitter according to the CRC check results. - View Dependent Claims (15, 16, 17, 18, 19)
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20. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, a method of determining the selected masked information bit sequence received from a transmitter, the method comprising the steps of:
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generating an FFT (Fast Fourier Transform) sequence by fast-Fourier-transforming a received masked information sequence;
symbol-demapping the FFT sequence;
channel-decoding the demapped information sequence;
masking the decoded information sequence with a predetermined mask sequence and checking errors by CRC (Cyclic Redundancy Code) bits of the masked information sequence; and
detecting a mask sequence selected by a transmitter according to the CRC check result and generating information bits by masking the decoded information sequence with the detected mask sequence. - View Dependent Claims (21)
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22. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, an apparatus for determining the selected masked information bit sequence received from a transmitter, the apparatus comprising:
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a FFT (Fast Fourier Transformer) for generating an FFT sequence by fast-Fourier-transforming a received masked information sequence;
a masker for masking the FFT sequence with a plurality of different mask sequences used by a transmitter;
a CRC (Cyclic Redundancy Code) checker for checking errors by CRC bits of each of the masked information sequences; and
a selector for detecting a mask sequence selected by the transmitter according to the CRC check results and selecting a masked information sequence corresponding to the detected mask sequence. - View Dependent Claims (23, 24, 25, 26)
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27. In an OFDM (Orthogonal Frequency Division Multiplexing) system where the same information bit stream is masked with a plurality of different mask sequences and a masked information bit sequence having the lowest PAPR (Peak to Average Power Ratio) is selected for transmission among a plurality of masked information bit sequences, an apparatus for determining the selected masked information bit sequence received from a transmitter, the apparatus comprising:
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an FFT (Fast Fourier Transformer) for generating an FFT sequence by fast-Fourier-transforming a received masked information sequence;
a symbol demapper for demapping the FFT sequence;
a channel decoder for decoding the demapped information sequence;
a masker for masking the decoded information sequence with a predetermined mask sequence;
a CRC (Cyclic Redundancy Code) checker for checking errors by CRC bits of the masked information sequence; and
a controller for detecting a mask sequence selected by a transmitter according to the CRC check result and generating information bits by masking the decoded information sequence with the detected mask sequence. - View Dependent Claims (28, 29)
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Specification