Performance Evaluation of Next Generation Wi-Fi : Link Asymmetry in Multi-Link Operation

Sammanfattning: With the growing demand for high-speed data transmission, the Institute of Electrical and Electronics Engineers (IEEE) study group, particularly IEEE 802.11, which focuses on Wireless Fidelity (Wi-Fi) technologies, has been actively pursuing advancements to meet these escalating requirements. One such endeavor is the exploration of Millimeter Wave (mmWave) communications. However, mmWave communications differ significantly from traditional communication systems, characterized by factors like high propagation loss, directivity, and susceptibility to blockage. These distinctive attributes present numerous challenges that must be addressed to fully exploit the potential of mmWave communications. The 802.11be amendment, which will be advertised as Wi-Fi 7, introduces several features that aim to enhance the capabilities of Wi-Fi. One of the main features introduced in this amendment is the Multi-Link Operation (MLO) which allows nodes to transmit and receive over multiple links concurrently. The objective of this project is to assess the performance of integrating MLO with an additional mmWave link in comparison to using a single mmWave link. The aim is to determine whether this combination can effectively address challenges within mmWave communications and consequently enhance throughput performance. Experimental simulations were conducted using an event-based Radio Access Technology (RAT) simulator, considering various scenarios and setups. These investigations examined the impact of factors such as link bandwidth, the number of links in MLO, on Wi-Fi performance. Our findings demonstrate the potential of combining MLO with an additional mmWave link, highlighting significant improvements in overall throughput. However, our results also reveal a link asymmetry problem that arises when integrating links with substantial differences in link capacity. This problem manifests in a specific region where the performance of MLO is not as well as that of using a single mmWave link. To address this issue, we propose a potential solution, which we thoroughly investigate through multiple simulations to assess its feasibility and effectiveness.