Cross-layer wireless video adaptation: Tradeoff between distortion and delay

Adaptive scheduling is becoming an increasingly important issue in wireless video communications, which are widely used in the industry and academic organizations. However, existing scheduling schemes for real-time video services in wireless networks generally do not take into account the relationship between the transmission delay and video distortion. In this paper, we develop and evaluate a delay-distortion-aware wireless video scheduling scheme in the framework of cross-layer information adaptation. At first, we construct a general video distortion model according to the observed wireless network parameters, as well as each video sequence’s rate-distortion characteristic. Then, we exploit a distortion-aware wireless video scheduling scheme and derive a bound on the asymptotic decay rate of the video distortion. Furthermore, the relationship between the delay and distortion is studied by taking into account video application delay and distortion requirements for specific wireless network environments. The proposed scheme is applied to heuristically find optimal tradeoff between the delay and distortion. Extensive examples are provided to demonstrate the effectiveness and feasibility of the proposed scheme.