Meta-surfaces intend to improve significantly the performance of future wireless networks by controlling the wireless propagation and shaping the radio waves according to the generalized Snell's law. A recent application of meta-surfaces is reconfigurable intelligent surfaces which are practically limited by the requirement for perfect knowledge of the user's position. For the case where the user's position cannot be obtained, we introduce randomly reconfigurable surfaces (RRSs) aiming to diffuse the incoming wave. A RRS is defined as a reconfigurable meta-surface that each of its elements induces a randomly selected time-variant phase shift on the reflected signal. To facilitate the performance analysis of a RRS-assisted system, first, we present novel closed-form expressions for the probability density function, the cumulative distribution function, the moments, and the characteristic function of the distribution of the sum of double-Nakagami-m random vectors, whose amplitudes follow the double-Nakagami-m distribution, i.e., the distribution of the product of two Nakagami-m random variables, and phases follow the circular uniform distribution. We also consider a special case of this distribution, namely the distribution of the sum of Rayleigh-Nakagami-m random vectors. Then, we exploit these expressions to investigate the performance of the RRS-assisted composite channel, assuming that the two links undergo Nakagami-m fading and the equivalent phase follows the circular uniform distribution. Closed-form expressions for the outage probability, the average received signal-to-noise ratio, the ergodic capacity, the bit error probability, the amount of fading, and the channel quality estimation index are provided to evaluate the performance of the considered system. These metrics are also derived for the practical special case where one of the two links undergoes Rayleigh fading.
翻译:元表层意图通过控制无线传播和根据普遍Snell法则塑造无线电波来显著改善未来无线网络的性能。 最近应用的元表层是可重新配置的智能表面,这些表面实际上受到对用户位置的绝对了解要求的限制。对于无法获得用户位置的情况,我们采用随机重新配置的表面(RRS),目的是传播进波。RRS被定义为可重新配置的元表层,每个元素都会在反射信号上随机选择时间变化阶段的变化。为了便利RRS辅助系统的性能分析,我们首先为概率密度功能、累积分布功能、时刻和双-纳卡-m 随机矢量的分布提供了新的封闭形式表达方式。对于双- 纳卡穆-m 流流流流流流流分布,即两个纳卡- 随机流动变量的分布方式, 提供了两个 Nakami-m 随机变量的分布阶段, 也就是循环流流流流流流流流流流流流流流流流流流流流数据,我们考虑一个特殊的状态分配情况, 流流流流流流流流流流流流流流流流流流流流流流流流数据到流流流流数据到流流流流流数据到流流流流流流流流流流流流数据到流流流流流流流流流数据到流流流流流流流流流流流流流流流流流流流流流流流流流流流流流流流流流流数据。我们。