APPARATUS AND METHOD FOR ESTIMATING FREQUENCY OFFSET IN UPLINK OF ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM

• Main Authors: HWANG, JONG YOON, WHANG, KEUM CHAN, CHO, DONG KYOON, KIM, KWANG SOON
• Format: Patent
• Language: English
• Published: 04.01.2008
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

An apparatus and a method for estimating a frequency offset in an uplink of an OFDMA(Orthogonal Frequency Division Multiple Access) system are provided to estimate a frequency offset efficiently without inducing power consumption and complexity of a base station receiver. An apparatus for estimating a frequency offset in an uplink of an OFDMA system includes an observation window setting unit(701), a fourier transform unit(702), a phase compensation unit(703), a subcarrier selector(704), and a frequency offset estimation unit(706). The observation window setting unit outputs at least two time domain signals having a predetermined time delay difference from a received signal through first and second observation windows having a different time delay. The fourier transform unit transforms at least two time domain signals to at least two frequency domain signals. The phase compensation unit compensates a phase change by a time delay difference between the first observation window and the second observation window. The subcarrier selector selects subcarriers of a specific user for estimating the frequency offset in at least two frequency domain signals of which a phase change is compensated. The frequency offset estimation unit calculates a phase difference of subcarriers having the same subcarrier index from the selected subcarriers. The frequency offset estimation unit estimates a frequency offset for a received signal of a specific user based on the phase difference.