# A Distributed Energy-Throughput Efficient Cross-Layer Framework Using Hybrid Optimization Algorithm
###### Abstract
In the literature, numerous significant contributions have been reported regarding terrestrial WSNs. In [12], a comprehensive cross-layer study is conducted to characterize network connectivity in CDMA-based WSNs, considering a multiuser access interference (MAI). [PERSON] et al. [13] present a cross-layer optimization approach for synchronous small-scale transmission networks, addressing the trade-off between energy consumption and delay. [PERSON] and [PERSON] [14] propose an initiative concept of an individual layer module to simultaneously address medium access control, routing, and congestion control in terrestrial WSNs. To effectively utilize the high-delay underwater medium and support differentiated services, [PERSON] and [PERSON] [15] introduce a multimedia cross-layer framework. While the mentioned examples focus on terrestrial WSNs, similar cross-layer approaches can also be applied to underground WSNs. The unique characteristics of underground environments, such as high propagation delay and limited bandwidth, necessitate tailored cross-layer solutions to optimize performance and resource utilization. In underground WSNs, cross-layer techniques can be employed to address challenges like energy efficiency, data delivery reliability, and support for multimedia data. By integrating functionalities from multiple layers, underground WSNs can benefit from coordinated and optimized operations, enhancing the overall efficiency and performance of the network. As the field of WSNs continues to advance, cross-layer design and optimization will play a crucial role in tailoring solutions to specific application scenarios and addressing the inherent challenges of different environments, including underground environments. The challenges associated with wireless EM communication in underground environments [2] limit the applicability of the aforementioned solutions from the existing literature. These challenges necessitate the development of specialized solutions to overcome the obstacles presented by the underground environment. Inferences from the literature highlight the significance of WUSNs, the challenges faced in wireless communication, the benefits of MI-based solutions, and the advantages of employing a cross-layered architecture for efficient and reliable communication in WUSNs. The recent advancement in MI-WUSNs has opened up new research challenges that need to be addressed to fully exploit the potential of this technology. As MI-WUSNs are deployed for various applications, they may need to interface with other types of WSNs in the same environment. For example, MI-WUSNs could be used in conjunction with WUSNs for deep ocean exploration or naval border defense. Properly designing the interfacing mechanisms between these different types of WSNs is essential to ensure seamless communication and collaboration. MI waveguide networks that utilize both active and passive relaying offer advantages such as low path loss and minimized frequency levels. However, the challenge lies in determining the appropriate location and operation pattern for each relay in the network to achieve optimal performance. To further improve signal quality and other output parameters in MI-WUSNs, deploying multiple orthogonal coils for each transceiver node can be beneficial. However, this approach presents challenges related to node misalignment and requires careful design to ensure a specific degree of connectivity is maintained. While cross-layer optimization is often suggested to enhance system performance, a more challenging issue is multi-objective optimization. This involves optimizing system efficiency in terms of multiple conflicting objectives, such as energy efficiency and network throughput. Achieving a balance between these objectives can be complex and requires sophisticated optimization techniques.