Reconfigurable intelligent surfaces (RISs) and cell-free (CF) massive multiple-input multiple-output (MIMO) are two promising technologies for sixth-generation (6G) networks. This paper investigates the achievable uplink sum rate of a RIS-aided CF massive MIMO system considering electromagnetic interference (EMI) at the RISs and imperfect channel state information (CSI). Our focus is on proposing an integrated approach that optimizes the beamforming at the access points (APs) and the RIS phase shift alternately using successive convex approximation and penalty convex-concave procedures to maximize the uplink sum rate. The results demonstrate that the proposed algorithm significantly improves the performance of the RIS-aided CF massive MIMO system and effectively mitigates the interference caused by EMI and imperfect CSI. Additionally, we find that the negative impact of EMI becomes more pronounced as the channel uncertainty increases. Moreover, increasing the number of RIS reflecting elements proves beneficial, but the returns diminish as the number of RIS elements becomes sufficiently large. Furthermore, deploying RIS beyond a certain limit of EMI power leads to degradation in system performance.


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    Title :

    Joint Beamforming and Phase Shift Design for RIS-Aided Cell-Free Massive MIMO Systems with Electromagnetic Interference and Imperfect CSI


    Contributors:
    Wen, Shuxian (author) / Shi, Enyu (author) / Lu, Yu (author) / Zhang, Jiayi (author) / Ai, Bo (author)


    Publication date :

    2024-06-24


    Size :

    374451 byte





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English