Abstract:

LUT (Look\|Up Table) address indexing algorithm of the traditional LUT predistortion method doesn't concern the distribution characteristic of OFDM (Orthogonal Frequency Division Multiplexing) signal, which causes the inconsistent problem of the values of LUT update frequency. In order to solve this pro
blem, a novel exponential LUT indexing algorithm is proposed which is based on the statistic characteristic of the OFDM signal. Through introducing the distribution characteristic of OFDM signal into the LUT indexing algorithm, the values of LUT update frequency finally tend to be consistent. Without inc
reasing the complexity, the novel algorithm improves the precision of the system nonlinear predistortion adjustment. The simulation results indicate that, under the same size of the Look up Table, the novel method has better BER (Bit Error Ratio) performance than the traditional algorithm. And the LUT index of the novel method changes from signal amplitude to signal power, which makes the hardware easier to be implemented in reality.
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Key words: power amplitude, predistorter, orthogonal frequency division multiplexing（OFDM）, look-up table(LUT), amplitude characteristic