Multi-Layer Optimization Framework for Video Transmission Over Multi-Hop Wireless Smart Utility Network Field Area Networks

The Wireless Smart Utility Network Field Area Network (Wi-SUN FAN) is an IPv6-based multi-hop wireless standard that achieves a high throughput of several hundred kilobits per second, approximately 10–100 times that of typical low-power wide-area technologies, while maintaining low power consumption. However, transmitting video over a Wi-SUN FAN is challenging as high-rate streams of numerous short real-time transport protocol (RTP) packets incur a considerable per-packet overhead, significantly reducing the efficiency. This study proposes an application-layer multi-layer optimization framework for H.265/RTP transmission over standard Wi-SUN FAN protocols. The framework comprises three components: 1) selective exclusion of redundant network abstraction layer units at the source (access unit delimiters and selected video usability information) under conditions validated to have no perceptual impact; 2) near-maximum transmission unit-sized user datagram protocol (UDP) aggregation, which bundles multiple RTP payloads to reduce channel-access attempts; and 3) reliability-constrained rate planning, which maps the hop count and stream concurrency to a minimum emission interval and sustainable per-stream bit rate to satisfy a target end-to-end packet delivery ratio (PDR). The framework was evaluated in a ladder network environment using large-scale computer simulations and a hardware testbed, targeting a video surveillance use case. Video quality was assessed using video multi-method assessment fusion (VMAF). Results show that handling multiple camera streams achieves a stable, practical-quality VMAF score of approximately 80 while reducing wireless UDP datagrams by up to 84.5%. A topology-indexed lookup table maps the hop count and stream concurrency to a safe emission rate, enabling 99.9% PDR in practical deployments.