Patent ID: 8681885

Claim:
An orthogonal frequency division multiplexing (OFDM) receiver for compensating for I/Q imbalance, comprising: an I/Q demodulator demodulating a received signal into a baseband in-phase (I) channel signal and a baseband quadrature (Q) channel signal; an I/Q imbalance compensator compensating for imbalance between the I-channel signal and the Q-channel signal in a time domain; and a frequency offset compensator compensating for a frequency offset, wherein the I/Q imbalance compensator is located upstream of the frequency offset compensator to compensate imbalance between the I-channel signal and the Q-channel signal caused by demodulation in the I/Q demodulator, and wherein the I/Q imbalance compensator is located downstream of the frequency offset compensator to compensate imbalance between an I-channel signal and a Q-channel signal caused by I/Q modulation in a transmitter, wherein the I/Q imbalance compensator makes the I-channel signal r I (t) and the Q-channel signal r Q (t) orthogonal to each other, orthogonal I and Q channel signals r I °(t) and r Q °(t) being generated from the following equations: r I °( t )= r I ( t )/sqrt( P I ) r Q ′( t )= r Q ( t )−ρ r I ( t )/ P I ,ρ=E{r I ( t ), r Q ( t )} r Q °( t )= r Q ′( t )/sqrt( P Q ) where P I and P Q are average power of r I (t) and average power of r Q ′(t), respectively.