Patent ID: 7269782

Claim:
A system for transmitting sub-channels having a minimum peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplexing (OFDM) communication system, the system comprising: a pilot scrambling code generator for generating a predetermined number of pilot scrambling codes for identifying pilot sub-channel data blocks among input sub-channel data blocks; a scrambling code generator for generating a predetermined number of scrambling codes for scrambling the input sub-channel data blocks; a plurality of first multipliers for multiplying the input pilot sub-channel data blocks by a first pilot scrambling code among the pilot scrambling codes, for scrambling; a plurality of second multipliers for multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and data blocks output from the first multipliers by a first scrambling code among the scrambling codes, for scrambling; a first inverse fast Fourier transformer (IFFT) for IFFT-transforming the signals output from the second multipliers; a plurality of third multipliers for multiplying the input pilot sub-channel data blocks by a second pilot scrambling code among the pilot scrambling codes, for scrambling; a plurality of fourth multipliers for multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and data blocks output from the third multipliers by a second scrambling code among the scrambling codes, for scrambling; a second IFFT for IFFT-transforming the signals output from the fourth multipliers; first and second PAPR calculators for calculating PAPRs of the sub-channel data blocks output from the first IFFT and the second IFFT, respectively; and a selector for selecting sub-channel data blocks output from the first and second IFFTs having a minimum PAPR among the calculated PAPRs, and transmitting the selected sub-channel data blocks over a sub-channel of the OFDM communication system.