Method and apparatus for reducing peak power in partial transmit sequence OFDM

An OFDM receiving apparatus for receiving a signal from an OFDM transmitting apparatus, comprising:

• a correlator for separating a received signal into M sub-blocks using the orthogonality of frequencies in the signal;
• a phase factor eliminator for multiplying the separated data of length L from each sub-block by a predetermined inverse phase factor;
• M inverse coefficient multipliers for multiplying each of the output data with length L received from the phase factor eliminator by predetermined coefficients to eliminate orthogonal components from frequency components of the output data;
• M FFTs (Fast Fourier Transformers) for performing L-point FFT on the output data with length L received from each inverse coefficient multiplier;
• and
• a deinterleaver for deinterleaving the output data received from the FFTs to recover an original data of the received output data.

An OFDM receiving apparatus for receiving a signal of which the peak power is decreased by performing L-point IFFT by

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• and using a predetermined coefficient multiplier, the apparatus comprising:
• a correlator for separating a received signal of length into M sub-blocks using the orthogonality of frequencies in the signal;
• a phase factor eliminator for multiplying the separated data with Length L from each sub-block by a predetermined inverse phase factor;
• M inverse coefficient multipliers for multiplying each of the output data with length L of each sub-block received from the phase factor eliminator by predetermined coefficients to eliminate orthogonal components from the frequency components of the signal;
• M FFTs for performing L-point FFT on the output data with length L received from each inverse coefficient multiplier;
• and
• a deinterleaver for deinterleaving signals received from the FFTs to recover an original signal of the received signal.

A method of transmitting an OFDM signal from an OFDM transmitting apparatus, comprising the steps of:

• dividing serial data to be transmitted into data blocks of length N;
• distributing the data of the divided data block of length N to M sub-blocks one by one rotationally;
• performing L(N/M)-point IFFT on distributed N/M data assigned to each M sub-block;
• multiplying the N/M data output from each IFFT by predetermined coefficients to give orthogonality to the frequency components of the N/M output data;
• generating optimal M phase factors to minimize a PAPR using the coefficient multiplication results;
• multiplying the M optimized phase factors by the multiplication results;
• and
• summing the products of the phase factors and the coefficient multiplication results on a symbol-to-symbol basis.

A method of receiving a signal from an OFDM receiving apparatus, comprising the steps of:

• separating a received signal of length N into M sub-blocks using the orthogonality of frequencies in the signal;
• multiplying the separated data of length L from each sub-block by a predetermined inverse phase factor;
• multiplying each output data of length L from the M sub-blocks by predetermined coefficients to eliminate orthogonal components from frequency components of the output data;
• performing L(N/M)-point FFT on the multiplied data of length L;
• and
• deinterleaving the L-point FFT output data to recover an original data.

An OFDM transmitting apparatus, comprising:

• a rotational sub-block partitioner for distributing parallel data blocks of length N to M sub-blocks one by one rotationally so that N/M data of length L is assigned to each sub-block;
• M IFFTs for performing L(N/M)-point IFFT on the N/M data assigned to each of the M sub-blocks;
• M coefficient multipliers for multiplying the N/M data output from each IFFT by predetermined coefficients to give orthogonality to the frequency components of the N/M output data;
• a phase factor optimizer for generating M phase factors to minimize a PAPR using the output of each coefficient multiplier;
• M multipliers for multiplying the optimized M phase factors by the outputs of the coefficient multipliers;
• and
• an adder for summing the outputs of the M multipliers on a symbol-to-symbol basis.

An apparatus of recovering original data in OFDM (Orthogonal Frequency Division Multiplexing) system, comprising:

• a rotational sub-block partitioner for partitioning the input data block of length N into M, the number of sub-block, and distributing the partitioned data of length L (N/M) into M sub-blocks one by one rotationally;
• M IFFTs (Inverse Fast Fourier Transformers) for performing L-point IFFT on the successive N/M data assigned to each M sub-block;
• M coefficient multipliers for multiplying the N/M data output from each IFFT by predetermined coefficients;
• M inverse coefficient multipliers for multiplying each output data of length L received from the phase factor eliminator by the inverse number of the predetermined coefficients transmitted from the M coefficient multipliers;
• and
• M FFTs (Fast Fourier Transformers) for performing L-point FFT on the output data of length L received from the corresponding inverse coefficient multipliers.

A method of recovering original data in OFDM (Orthogonal Frequency Division Multiplexing) system, comprising the steps of:

• distributing the input data of the data block of length N to M sub-blocks one by one rotationally;
• performing L(N/M)-point IFFT on successive N/M data assigned to the corresponding M sub-blocks;
• multiplying the N/M data output from each IFFT by predetermined coefficients;
• multiplying each output data of length L from the M sub-blocks by inverse number of the coefficients generated;
• and
• performing L(N/M)-point FFT on the multiplied data of length L.