可重构智能表面通信系统的渐进信道估计方法

Progressive channel estimation method for RIS-assisted communication system

针对现有可重构智能表面(reconfigurable intelligent surface, RIS)的信道估计方法中反射系数为随机配置而导致接收端信噪比较低的问题,提出一种配置特定反射系数的渐进式信道估计方法。该方法利用非完整信道状态信息(channel state information, CSI)计算出当前时刻下的最优反射系数,然后将该最优反射系数与随机反射系数按照加权系数生成混合反射系数。在下一时刻RIS配置该混合反射系数,接收端使用松弛最小均方误差(relaxed minimum mean square error, RMMSE)信道估计方法来更新非完整信道状态信息。仿真结果表明,所提方法不仅能获得准确的信道估计结果,也能在估计过程中不断增大接收端信噪比,并减小导频开销,从而提高RIS辅助无线通信系统的频谱效率。

Aiming at the problem that the reflection coefficient is randomly configured in the existing channel estimation methods of reconfigurable intelligent surface(RIS), resulting in low signal-to-noise ratio at the receiver, a progressive channel estimation method with specific reflection coefficient is proposed. In this method, the optimal reflection coefficient at the current time is calculated by using the incomplete channel state information(CSI). And then, the optimal reflection coefficient and the random reflection coefficient are used to generate the mixed reflection coefficient according to the weighting coefficient. The RIS configures the hybrid reflection coefficient at the next time, and the receiver uses the relaxed minimum mean square error(RMMSE) channel estimation method to update the incomplete channel state information. Simulation results show that the proposed method can not only obtain accurate channel estimation results, but also continuously increase the signal-to-noise ratio of the receiver and reduce the pilot overhead in the estimation process, so as to improve the spectral efficiency of RIS-assisted wireless communication system.