Transmission Through Large Intelligent Surfaces: A New Frontier in Wireless Communications

Abstract: In this paper, transmission through large intelligent surfaces (LIS) that intentionally modify the phases of incident waves to improve the signal quality at the receiver, is put forward as a promising candidate for future wireless communication systems and standards. For the considered LIS-assisted system, a general mathematical framework is presented for the calculation of symbol error probability (SEP) by deriving the distribution of the received signal-to-noise ratio (SNR). Next, the new concept of using the LIS itself as an access point (AP) is proposed. Extensive computer simulation results are provided to assess the potential of LIS-based transmission, in which the LIS acts either as an intelligent reflector or an AP with or without the knowledge of channel phases. Our findings reveal that LIS-based communications can become a game-changing paradigm for future wireless systems.

• The paper introduces a mathematical framework to evaluate symbol error probability in LIS systems, leveraging phase control to maximize SNR.
• It pioneers the use of LIS as access points by encoding data via phase adjustments, reducing reliance on conventional RF processing.
• Simulations demonstrate that LIS systems significantly enhance reliability, with SNR gains proportional to the square of the reflecting elements.

Transmission Through Large Intelligent Surfaces: A New Frontier in Wireless Communications

The paper "Transmission Through Large Intelligent Surfaces: A New Frontier in Wireless Communications" by Ertugrul Basar explores the potential of Large Intelligent Surfaces (LIS) to transform wireless communication systems. This research introduces LIS-assisted communication as a novel paradigm that could offer significant improvements in signal quality and pave the way for new transmission schemes in future-generation wireless networks, including 6G.

The study presents a mathematical framework for evaluating the symbol error probability (SEP) in LIS-based systems by analyzing the distribution of the received signal-to-noise ratio (SNR). The unique proposition of this paper is to utilize LIS not just as intelligent reflectors but also as access points (APs), where the surface itself facilitates data transmission by modifying incident wave phases. This innovative concept positions LIS as a versatile candidate for future communication infrastructures.

Key Contributions and Findings

1. Mathematical Framework: The paper establishes a comprehensive framework for analyzing the error performance of LIS-based communication systems, considering variables such as reflecting elements and modulation orders. It presents exhaustive simulation results demonstrating the potential of LIS both as intelligent reflectors and APs.
2. LIS as Access Points: A pioneering concept is introduced where LIS acts as an AP, exploiting unmodulated carrier signals transmitted towards the LIS. This approach highlights how LIS-induced phases can be adjusted to encode information, thereby eliminating the need for sophisticated RF processing at the AP.
3. Performance Evaluation: Extensive simulations reveal that LIS-assisted systems can achieve ultra-reliable communication at significantly lower SNR values compared to traditional methods. Notably, the gain in average received SNR is shown to be proportional to the square of the number of reflecting elements in intelligent transmission scenarios. The proposed LIS-based approaches consistently outperformed traditional BPSK over AWGN channels across various configurations and parameters.
4. Intelligent vs. Blind Transmission: The study delineates the performance differences between intelligent and blind transmission models based on the knowledge of channel phases. Intelligent transmission offers superior performance by maximizing SNR through precise phase compensation, while blind transmission still grants notable SNR improvements proportional to the number of LIS elements, albeit with reduced efficacy.
5. Use in 6G and Beyond: The findings suggest that LIS technology has the potential to supplant or complement existing MIMO and beamforming technologies in future systems, providing transformative benefits in signal coverage, reliability, and overall system efficiency.

Implications and Future Directions

The successful implementation of LIS in practical systems can lead to substantial innovations in the telecommunications industry. Theoretical advancements outlined in this paper could redefine conventional approaches to wireless communications by minimizing dependence on complex coding and massive MIMO configurations. In practice, this translates into cost-effective and energy-efficient deployments.

Going forward, several avenues of investigation remain open. These include examining the effects of correlated channels, implementing LIS in multi-antenna configurations, exploring various fading conditions, and considering discrete phase adjustments. Moreover, integrating LIS concepts into non-traditional domains, such as the Internet of Things (IoT) and autonomous systems, could present further opportunities and challenges.

Overall, LIS-based communication represents a promising advance in wireless technology, with the potential to influence future standards and network architectures. This paper provides a foundational basis for more detailed explorations and experimental validations of LIS capabilities in real-world scenarios.