Signal transmitting apparatus for OFDM system and parameter adjusting method thereof
AssigneeRalink Technology Corporation
InventorsJiunn Tsair Chen, Yun Shen Chang, Chih Hung Lin
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Abstract
A signal transmitting apparatus for orthogonal frequency division multiplexing (OFDM) system comprises a compandor, a predistortor, a power amplifier and a feedback module. The compandor is configured to compress and expand a transmitted signal. The predistortor is configured to perform a predistortion operation on output signals of the compandor. The power amplifier is configured to amplify output signals of the predistortor. The feedback module is configured to adjust parameters of the compandor and the predistortor based on a feedback signal.
Claims18
A signal transmitting apparatus for orthogonal frequency division multiplexing (OFDM) system, comprising:
- a compandor configured to compress and expand a transmitted signal;
- a predistortor configured to perform a predistortion operation on an output signal of the compandor;
- a power amplifier configured to amplify an output signal of the predistortor;
- and
- a feedback module configured to adjust the compandor and the predistortor based on a feedback signal;
- wherein the feedback module comprises:
- a delay unit configured to delay an input signal of the predistortor;
- an adaptive operation unit configured to adjust parameters of the predistortor based on an output signal of the delay unit and the feedback signal;
- an inverse compandor configured to perform an inverse operation of the compandor on an output signal of the adaptive operation unit;
- and
- a comparator configured to adjust parameters of the compandor and inverse compandor based on a comparison result of the output signal of the compandor and an output signal of the inverse compandor.
A signal transmitting apparatus for orthogonal frequency division multiplexing (OFDM) system, comprising:
- a companding feedback module configured to compress and expand a transmitted signal;
- a predistortion feedback module configured to perform a predistortion operation on an output signal of the companding feedback module and to output a feedback signal to the companding feedback module;
- and
- a power amplifier configured to amplify an output signal of the predistortion feedback module and to couple the amplified signal to the predistortion feedback module;
- wherein the companding feedback module comprises:
- a compandor configured to compress and expand the transmitted signal;
- an inverse compandor configured to perform an inverse operation of the compandor on the feedback signal;
- and
- a comparator configured to adjust the compandor and the inverse compandor based on a comparison result of output signals of the compandor and the inverse compandor;
- wherein the companding feedback module and the predistortion feedback module alternatively adjust their parameters.
Dependencies are inferred from the claim text.