Linear companding transform (LCT) is one of the most attractive schemes to deal with the inherent problem of high peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems, due to its effectiveness and low complexity. In this paper, a generalized continuous piecewise linear companding (CPLC) transform is proposed. The companding and decompanding functions of the proposed scheme consist of multiple continuous linear segments, and the total number of segments is generalized to be any integer not less than four. These linear segments can provide much adaptability for function shaping, leading to high flexibility for performance tradeoffs among PAPR reduction, bit error rate (BER), out-of-band (OOB) rejection and algorithmic complexity. The continuity of the companding function helps to reduce OOB radiations. Several optimization problems with different targets under the constraint condition of constant average power are constructed. Permissible ranges of key parameters, relationships among these parameters and their influence on algorithmic performance are analyzed. Parameter selecting strategies are also provided. In addition, an iterative receiving method is designed to reduce system BER effectively at the receiver. Simulation results validate the performance superiorities of the proposed scheme to that of other typical companding schemes.

中文翻译：

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用于 OFDM 系统中 PAPR 降低的广义连续分段线性压扩变换设计


线性压扩变换（LCT）由于其有效性和低复杂性，是解决正交频分复用（OFDM）系统中高峰均功率比（PAPR）固有问题的最有吸引力的方案之一。本文提出了一种广义连续分段线性压扩（CPLC）变换。该方案的压扩和解压函数由多个连续的线性段组成，并且段的总数被推广为不小于4的任意整数。这些线性段可以为函数整形提供很大的适应性，从而为 PAPR 降低、误码率 (BER)、带外 (OOB) 抑制和算法复杂性之间的性能权衡提供高度灵活性。压扩功能的连续性有助于减少 OOB 辐射。构造了平均功率恒定约束条件下多个不同目标的优化问题。分析了关键参数的允许范围、参数之间的关系及其对算法性能的影响。还提供了参数选择策略。此外，设计了迭代接收方法，可以有效降低接收端的系统误码率。仿真结果验证了该方案相对于其他典型压扩方案的性能优势。