Adaptive Superframe Structures for Real-Time Applications in IEEE 802.15.7-Based Visible Light Communication Networks: A Comprehensive Review

With the introduction of Visible Light Communication (VLC), a new possibility of high-speed, secure, and interference-free wireless communications, both indoor and in real time, has presented itself. The most important standard regulating VLC is the IEEE 802.15.7, which offers medium access control (MAC) protocols designed to suit optical wireless networks. Nonetheless default superframe design in the standard might not be adequate to address the strict needs of latency, reliability and energy consumption of the real-time sensor networks. Dynamic adaptive superframe structures, which adjust the contention-based and contention-free periods allocations, have turned out to be a viable solution to these difficulties. The scenario of adaptive superframe methods on IEEE 802.15.7-based VLC networks is systematically reviewed with a focus on real-time applications. We examine dynamic GTS allocation schemes, energy-aware scheduling, speed adaptive designs and hybrid VLC RF MAC protocols. In addition, we find major bottlenecks of existing designs, including scales, synchronicity, and mobility facilitation. The paper ends with a summary of some of the existing problems along with indicating possible areas of research that can make future VLC systems have intelligent, flexible and efficient MAC-layer solutions.