This paper investigates the diversity gain of a distributed cyclic delay diversity (dCDD) scheme for cyclic-prefixed single carrier systems in non-identical fading channels. Non-identical small-scale fading is assumed in the environment, in which non-identical line-of-sight and non-line-of-sight fading coexist. A condition for dCDD resulting in intersymbol interference free reception at the receiver, is extended to this new channel environment. For an overpopulated system setup, a generalized performance analysis, is not available from existing works, is conducted after developing closed-form expressions for the distribution of the signal-to-noise ratio (SNR) realized at the receiver. Since the order statistics are involved in the statistical properties of the SNR, the corresponding spacing statistics are utilized to derive feasible closed-form expressions. The finalized closed-form expressions are shown to provide very reliable outage probability and spectral efficiency of dCDD for underpopulated and overpopulated systems. An asymptotic performance analysis verifies the maximum achievable diversity of the dCDD even in the overpopulated case within the considered channel environment. Link-level simulations are conducted and these verify the maximum achievable diversity gain.

中文翻译：

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不同衰落信道中分布式CDD系统的分集增益分析


本文研究了不同衰落信道中循环前缀单载波系统的分布式循环延迟分集 (dCDD) 方案的分集增益。假设在不同视线和非视距衰落共存的环境中存在不同小尺度衰落。导致接收机处无码间干扰接收的 dCDD 条件被扩展到这个新的信道环境。对于人口过多的系统设置，在开发接收机处实现的信噪比 (SNR) 分布的封闭式表达式后，可以进行现有工作中无法进行的广义性能分析。由于阶次统计涉及信噪比的统计特性，因此利用相应的间距统计来推导可行的封闭式表达式。最终确定的封闭式表达式可以为人口不足和人口过多的系统提供非常可靠的 dCDD 中断概率和频谱效率。渐近性能分析验证了 dCDD 的最大可实现多样性，即使在所考虑的信道环境内人口过多的情况下也是如此。进行链路级仿真并验证可实现的最大分集增益。