Adaptive hybrid digital-analog video transmission in wireless mobile networks

Abstract

This paper proposes an adaptive hybrid digital-analog video transmission scheme to eliminate cliff effect and improve user experience in wireless mobile networks. To achieve graceful degradation performance, each Group of Pictures (GOP) is transformed and efficiently compressed into a reference frame and several Motion Vector (MV) frames with Motion-Compensated Temporal Filtering (MCTF). Then, the critical reference frame is transmitted as base data in a reliable digital mode. MV frames in units of chunks are transmitted as enhancement data in an analog mode where power allocation is optimized among chunks based on their entropy. To combat channel fading, each chunk in MV frames is further divided into subbands with consideration of the channel coherence time. Then, Adaptive Power Distortion Optimization (APDO) with channel prediction is performed among the subbands within each chunk to provide error resilience with adaptive scaling factors varying with channel conditions. Simulation results show that the proposed scheme outperforms Softcast (about 5.6 ~ 10.3dB) and Parcast (about 0.9 ~ 6.1dB) in terms of Peak Signal-to-Noise Ratio (PSNR) under various degrees of channel fading. Furthermore, the proposed scheme also works effectively when coping with channel fluctuation in high mobility scenarios.