Date Added: Aug 2012
Video streaming over wireless networks can achieve large quality and capacity gains from transmission techniques that are aware of the video content. This paper proposes modifying conventional Multiple-Input Multiple-Output (MIMO) systems to realize these gains by introducing video-aware PHY layer decisions. Specifically, a new PHY layer packet prioritization method is introduced that splits video data among spatial streams based on the packet loss visibility and per-stream SNRs. The objective is to maximize throughput weighted by packet loss visibility, a metric coined perceived throughput. The globally-optimal splitting policy among streams is derived. Furthermore, unequal modulation per stream is proposed and visibility-based packet dropping is optimized to satisfy delay constraints.