Method for estimating and compensating IQ imbalance in OFDM systems
AssigneeIndustrial Technology Research Institute
InventorsChao-Kai Wen, Jiun-Yo Lai, Yu-Tao Hsieh, Pang-An Ting
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Abstract
A method for compensating IQ imbalance is disclosed. First, an OFDM signal is received. The OFDM signal is translated into frequency domain, wherein the translated OFDM signal has N sub-carriers noted as Y(1)-Y(N). The IQ imbalance compensation factor is generated according to the k-th sub-carrier of the translated signal Y(k), the (N−k+2)-th sub-carrier of the translated signal Y(N−k+2), and the complex conjugates thereof.
Claims32
A method for compensating IQ imbalance, comprising:
- receiving an OFDM signal;
- translating the OFDM signal into frequency domain to form a translated OFDM signal, where the translated OFDM signal has N sub-carriers;
- and
- generating an IQ imbalance compensation factor according to the k-th sub-carrier of the translated signal, the (N−k+2)-th sub-carrier of the translated signal, and the complex conjugates thereof.
A method for compensating IQ imbalance, comprising:
- receiving an OFDM signal;
- translating the OFDM signal into frequency domain to form a translated OFDM signal, where the translated OFDM signal has N sub-carriers;
- and
- generating an IQ imbalance compensation factor according to a first matrix A, a conjugate transpose of the first matrix A*, and M sub-carriers of the translated OFDM signal.
A method for compensating IQ imbalance, comprising:
- calculating an IQ imbalance compensation factor of the n-th OFDM frame ρn by filtering ρn-1, wherein
- ρ
- n
- =
- γρ
- n
- -
- 1
- +
- (
- 1
- -
- γ
- )
-
- β
- α
- *
- ,
- where ρn-1 is a IQ imbalance compensation factor of the (n-1)-th frame, ρn is a IQ imbalance compensation factor of the n-th frame, γ is a factor which is not larger than one, and
- β
- α
- *
- is an estimated IQ imbalance compensation factor of the n-th frame.
Dependencies are inferred from the claim text.