A Two-Stage Frequency-Offset Estimation Scheme for OFDMA System

In OFDMA multiple access wireless communication systems, carrier frequency offsets between the transmitter and the receiver tend to destroy the orthogonality among subcarriers, and hence, introduces intercarrier interference. A two-stage frequency offset estimation algorithm based on subspace processing is proposed. The main advantage of the proposed method is that it can obtain the CFOs of all users simultaneously using only one OFDMA block. Compared with previously known methods, our system is seen not to have a relatively low implementation complexity, but is also suitable for random subchannel assignment.