基于OFDM信号分布的指数查询表索引算法

针对传统查表查询表项更新频率不一致的问题, 提出一种新型基于OFDM(Orthogonal Frequency Division Multiplexing)信号幅度统计特性的指数查询表索引算
法, 通过在查询表索引算法中引入OFDM信号幅度的分布特性, 使查表法的表项更新频率最终趋于一致, 达到提升系统的非线性失真矫正精度的目的, 同时不明显增加复杂度。仿真结果表明, 在查询表大小相同的条件下, 新型查询表索引算法比传统算法提升了系统的性能, 降低了饱和性失真的影响； 同时, 由于将索引目标由信号幅度改为信号功率, 使其硬件实现更为简单高效。

Exponential Look-Up Table Indexing Algorithm Using Distribution of OFDM Signal Characteristic

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 problem, 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 increasing 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.