Основные понятия
An active reconfigurable intelligent surface (RIS) can enhance the performance of massive MIMO uplink systems with low-resolution analog-to-digital converters (ADCs) by adjusting the phase shifts and amplifying the received signals.
Аннотация
The paper considers an active RIS-aided multi-user uplink massive MIMO system with low-resolution ADCs. The key highlights are:
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A closed-form approximate expression for the sum achievable rate (AR) is derived, where the maximum ratio combination (MRC) processing and low-resolution ADCs are applied at the base station.
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The system performance is analyzed, and a genetic algorithm (GA)-based method is proposed to optimize the RIS's phase shifts for enhancing the system performance.
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Numerical results verify the accuracy of the derivations and demonstrate that the active RIS has a notable performance gain over the passive RIS.
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Applying low-resolution ADCs in this system can balance the system performance with the deployment costs.
Статистика
The sum achievable rate increases as the number of base station antennas M and the number of RIS reflecting elements N go larger.
When the total power PT is lower than 20 dBm, the passive RIS outperforms the active RIS, but the active RIS can achieve a higher rate under sufficient energy conditions.
With 4-bit quantization, the system can achieve similar performance to the case with high-resolution ADCs.
Цитаты
"Active RIS is capable of approaching the upper limit of system performance while requiring fewer components such as M = 64 and N = 16."
"Applying low-resolution ADCs in this system can balance the system performance with the deployment costs."