RIS-Assisted Proactive Handover for Reliable mmWave Wireless Networks
For mmWave wireless networks facing LoS blockages, this work addresses the challenge of proactive handover when no nearby base station is available, offering a practical solution to maintain connectivity.
This work proposes a novel RIS-assisted proactive handover approach for mmWave networks that optimizes the number of RIS elements to balance complexity and link quality under timing constraints. Results show a 12% reduction in RIS elements yields a 10% decrease in energy without SNR loss, and a 15–30 dB SNR improvement in blocked regions.
Millimeter-wave (mmWave) networks are highly susceptible to line-of-sight (LoS) blockages. Vision-aided wireless communications (VAWC) enable proactive handovers (PHO) to mitigate such blockages; however, PHO becomes challenging when no nearby base station (BS) is available. In such cases, reconfigurable intelligent surfaces (RIS) can be used to restore connectivity. To ensure timely PHO, the RIS configuration time must be taken into account, as the large number of RIS elements can limit responsiveness in time-sensitive scenarios. This work proposes a novel RIS-assisted PHO approach that optimizes the number of allocated RIS elements to balance signal processing complexity and link quality under handover timing constraints, making the RIS-assisted link more energy-efficient. An optimization problem based on particle swarm optimization (PSO) is formulated to determine the optimal end-to-end RIS link setup that runs offline to bypass latency constraints. Results show that reducing the number of RIS elements by 12\% leads to a 10\% decrease in dissipated energy without compromising the signal-to-noise ratio (SNR). Moreover, the RIS-assisted link achieves a 15--30 dB improvement in blocked regions while maintaining accurate PHO timing.