This paper analyzes Type I hybrid automatic repeat request (HARQ) over time-correlated Rayleigh fading channels. Due to the presence of channel time correlation, the analysis is more challenging than the prior analysis in the literature. Outage probability is first derived as a weighted sum of joint CDF of multiple independent Gamma random variables based on an infinite series representation. A truncation method is proposed for efficient computation of the outage probability and it is proved that the truncation error decreases exponentially with the truncation order. Asymptotic outage probability is then derived in a simple form, with which the impacts of packet transmission rate, transmit power and channel time correlation could be decoupled and analyzed clearly. Based on the asymptotic outage probability, diversity order of HARQ is also analyzed. It is found that full diversity can be achieved even under time correlated fading channels and the time correlation of the channels has negative effect on the outage probability under high signal-to-noise ratio (SNR). Finally, our analytical results are validated by MonteCarlo simulations.
翻译:本文分析了与时间相关的Rayleigh 淡化频道的I型混合自动重复请求( HARQ) 。 由于频道时间相关性的存在, 此分析比文献中先前的分析更具挑战性。 外差概率首先作为多个独立的 Gamma 随机变量的合并 CDF 的加权总和得出, 其依据是无限序列表示法 。 为有效计算断流概率, 提出了一个脱轨方法, 并证明短跑误差会随着脱轨顺序而指数性地下降 。 然后, 以简单的形式得出失灵概率, 包状传输率、 传输功率和频道时间相关性的影响可以被分解和分析得更清楚。 基于无症状性溢出概率, 还分析了HARQ的多样性顺序 。 发现即使在时间相关淡化频道和频道的时间相关性对高信号到噪音比率( SNR) 下的外差概率都有负面影响 。 最后, 我们的分析结果通过 MonteCarlo 模拟得到验证 。