VEGA-360: Viewport-Aware Hierarchical Grouped Allocation for Multi-Layer 360° Video Streaming

Delivering multi-layer, tiled 360° video to multiple wireless users is challenging due to limited radio resources, heterogeneous channel conditions, and a strong viewport-dependent quality of experience (QoE). To address this problem, we propose Viewport-Enhanced Grouped Allocation for 360° Video (VEGA-360), a hierarchical viewport-aware resource allocation framework for multi-user 360° video streaming. VEGA-360 adopts a two-stage design. On the main stage, VEGA-360 partitions users into a small number of clusters using a joint criterion that combines spectral efficiency and viewport similarity derived from viewport weights and allocates a per-cluster resource budget accordingly. In the fine-tuning phase, VEGA-360 solves independent optimization subproblems per cluster at the tile granularity, enforcing radio resource and SHVC scalability constraints while maximizing a utility metric that accounts for viewport-weighted visual quality and the transmission overhead caused by distributing multiple tile instances. By separating coarse-grained grouping and budgeting decisions from fine-grained tile-layer allocation, VEGA-360 reduces the size of each optimization instance and improves computational tractability while maintaining viewport-aware service in dense multi-user scenarios. Simulation results show that VEGA-360 achieves competitive utility/QoE compared to a monolithic MILP baseline, with substantially shorter solution times.