论文标题
考虑多普勒效应的可重新配置智能表面辅助无线通信的频道估计
Channel Estimation for Reconfigurable Intelligent Surface-Assisted Wireless Communications Considering Doppler Effect
论文作者
论文摘要
在无线系统通过可重构智能表面（RISS）的帮助下，通道状态信息在实现RISS的性能增长方面起着关键作用。由于多普勒效应，机动性使准确的通道估计（CE）更具挑战性。在这封信中，我们提出了两个实用的宽带CE方案，其中包括多条路径和单路传播环境的多普勒偏移调整（DSA），用于与RIS辅助通信与被动反射元素有关。对于多路径方案，首先要执行普通CE，假设假设准静态通道，然后通过联合RIS反射模式选择和频率和时域之间的转换实现DSA。与原始CE所需的符号相比，提议的CE仅需要再增加一个符号可忽略的额外开销。对于特别适用于毫米波和Terahertz系统的单路案例，一种新型的低复杂性CE方法是在RIS的阵列因子的形式上设计出来的。仿真结果表明，所提出的算法具有较高的CE精度和可实现的速率，其复杂性低，并且表现优于代表性的基准方案。
In wireless systems aided by reconfigurable intelligent surfaces (RISs), channel state information plays a pivotal role in achieving the performance gain of RISs. Mobility renders accurate channel estimation (CE) more challenging due to the Doppler effect. In this letter, we propose two practical wideband CE schemes incorporating Doppler shift adjustment (DSA) for multi-path and single-path propagation environments, respectively, for RIS-assisted communication with passive reflecting elements. For the multi-path scenario, ordinary CE is first executed assuming quasi-static channels, followed by DSA realized via joint RIS reflection pattern selection and transformations between frequency and time domains. The proposed CE necessitates only one more symbol incurring negligible extra overhead compared with the number of symbols required for the original CE. For the single-path case which is especially applicable to millimeter-wave and terahertz systems, a novel low-complexity CE method is devised capitalizing on the form of the array factors at the RIS. Simulation results demonstrate that the proposed algorithms yield high CE accuracy and achievable rate with low complexity, and outperform representative benchmark schemes.
