第二讲 PC-CFR的使用细节问题(一) 解决方案, desired, 实际应用, higher, 如何

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第二讲 PC-CFR的使用细节问题(一)
本节着重想跟大家探讨一下关于PC-CFR 两级Iteration的原因和如何合理设置削峰门限来达到提高性能
阅读XAPP1033可以发现，在实际应用时，PC-CFR解决方案可以提供多种不同的配置，其中就有使用“两级Iteration”。
文档中关于这个问题给出了使用“两级Iteration”的原因：Performance can be improved by using a detection threshold that is slightly higher than the desired clipping threshold. This allows the algorithm to ignore peaks that are just barely crossing the threshold and focus on peaks that exceed the threshold by some delta. The main reason this provides improvement is the fact that some peak regrowth occurs, which can result in many near threshold peaks. Allocating CPG resources to these small peaks during a second iteration would provide minimal PAPR reduction with the risk of missing larger peaks that were not cancelled during the first iteration.
我对此的做过相应的测试，总结就是：使用两级Iteration，第一级的削峰门限要比理想值高一点，第二级接近理想值效果最佳。两级Iteration方案中，第2级的作用有2个：第一是the second iteration 继续处理the first iteration没有来的及处理的Peak;第二是the first iteration在对消的时候会在原来不存在Peak的地方引入了Peak（我们称之为peak regrowth现象），the second iteration对它进行进行消除。