3.2 峰值平均功率比性能仿真
在PAPR的性能仿真中，我们引入互补累积分布函数(CCDF)来描述信号的PAPR。图6所示为在16-QAM调制下的ZP-CI/OFDM、CI/OFDM和OFDM这3种信号的PAPR性能仿真结果。由图6的仿真结果可以看出，CI-OFDM系统由于CI码的引入从而具有很低的PAPR，ZP-CI/OFDM系统由于以添零的方式作为保护间隔使得PAPR略有提高，但也明显低于传统的OFDM系统。因此，ZP-CI/OFDM系统以较小的PAPR提高为代价，换取了更大的BER增益。
4 结束语
本文分析了OFDM技术作为宽带无线通信的主流传输技术所存在优缺点。由于OFDM技术存在功率效率问题，从而制约了以OFDM为核心的无线传输技术的发展。针对这一问题，本文给出了一种新的ZP-CI/OFDM无线传输技术。ZP-CI/OFDM技术通过载波干涉码将发射符号扩展到所有OFDM子载波上，在有效消除传统OFDM的PAPR的同时，充分利用多载波的频率分集增益；同时，通过在发射端添零，利用先进的接收机技术进一步利用频率分集增益，提高系统的功率效率。
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