Method and apparatus for improving PAPR in OFDM or OFDMA communication system

A method of diminishing peak to average power ratio (PAPR) in an OFDM or OFDMA communication system, the method comprising:

• a first step of circularly shifting each of at least two data sequences that have been converted to a time domain from a frequency domain according to first circular shift information to generate at least two circularly shifted data sequences, wherein circularly shifting each of the at least two data sequences comprises:
• storing each of the at least two data sequences, and
• outputting each of the stored at least two data sequences according to the circular shift information;
• a second step of combining the at least two circularly shifted data sequences to generate a combined data sequence;
• a third step of calculating the PAPR of the combined data sequence;
• and
• a fourth step of outputting an entire combined data sequence corresponding to a specific PAPR selected from a plurality of PAPRs calculated by repeating the first, second, and third steps at least once using circular shift information that is different from the first circular shift information.