Integrated access and backhaul with RIS: Analyzing inter-source and inter-user interference
Résumé
Integrated Access and Backhaul (IAB) systems are gaining more and more interest for future Wireless networks. IAB combines the access and backhaul links to improve network efficiency and reduce deployment costs. However, interference between different parts of the network can limit overall performance. Reconfigurable Intelligent Surfaces (RIS) have emerged as a promising technology for mitigating interference and enhancing network performance. In this paper, we investigate the use of RIS in IAB systems: we use the same RIS with several sources to simultaneously transmit signals to the Base Station and to several User Equipments. The RIS is unequally divided to generate different signal power levels. We analyze Inter-Source Interference (ISI) and Inter-User Interference (IUI). Our results show that ISI is negligible. However, we found that IUI can still be a limiting factor. To reduce IUI, we first uses a Genetic Algorithm, which is found to be effective in the case of large RIS but not in the case of small RIS. To further reduce the IUI in the small RIS case, the phases of the RIS are quantized in two and three bits. Our analysis shows that increasing the number of bits can significantly improve network performance by reducing IUI. Overall, our study highlights the potential benefits of using RIS in IAB systems and provides insights into the optimization of RIS signal processing for interference mitigation.
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