In portable wireless communication systems, power consumption is of major concern. Traditional modulation and coding schemes have been designed from the standpoint of minimizing average power. However, for linear power amplifiers needed for spectrally efficient modulation formats, amplifier efficiency and hence power consumption are determined by the peak power of the transmitted signal. This paper looks into modulation formats which minimize peak power and retain high spectral efficiency. Peak power is broken into a sum (in terms of decibels) of average power and a peak-to-average power ratio, and a variety of modulation formats are evaluated in terms of peak power efficiency in both a Gaussian noise and Rayleigh fading channel. A generalized phase shift keying (PSK) modulation format is developed and shown to offer superior peak power efficiency relative to that of commonly used linear modulation formats. Two schemes are presented for reducing the peak-to-average power ratio of various modulation formats. First, data translation codes are used to avoid data sequences which cause large peaks in the transmitted signal. This approach was found to be most productive in quadrature amplitude modulation (QAM) formats. Finally, an adaptive peak suppression algorithm is presented which further reduces the peak-to-average power ratios of the PSK and generalized PSK formats. The peak suppression algorithm is also applicable to /spl pi//4-QPSK and was found to improve peak power efficiency of that format by about 1.25 dB over a Rayleigh fading channel.
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机译：在便携式无线通信系统中，功耗是主要问题。从最小化平均功率的观点，已经设计了传统的调制和编码方案。然而，对于频谱有效调制格式所需的线性功率放大器，放大器效率以及因此的功耗取决于发射信号的峰值功率。本文研究了可最大程度降低峰值功率并保持高频谱效率的调制格式。峰值功率被分解为平均功率和峰均功率之和（以分贝为单位），并且根据高斯噪声和瑞利衰落信道中的峰值功率效率来评估各种调制格式。通用相移键控（PSK）调制格式得到了开发，并显示出相对于常用线性调制格式而言具有更高的峰值功率效率。提出了两种方案来降低各种调制格式的峰均功率比。首先，使用数据转换码来避免导致发射信号中出现大峰值的数据序列。发现这种方法在正交幅度调制（QAM）格式中效率最高。最后，提出了一种自适应峰值抑制算法，该算法进一步降低了PSK和广义PSK格式的峰均功率比。峰值抑制算法也适用于/ spl pi // 4-QPSK，并且发现它可以在瑞利衰落信道上将这种格式的峰值功率效率提高约1.25 dB。
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