Variance-Aware Adaptive Modulation for OFDM-Based Multiple Description Progressive Image Transmission

Abstract

Average throughput maximization has commonly been used as an alternative to image or video average distortion minimization. However, as the throughput-distortion curve is non-linear, throughput maximization can be very different from distortion minimization if the variance of the throughput is large. Under high channel quality variability, the variance of the throughput will be high. Multiple description coding with unequal error protection is a promising technique for the transmission of progressive images when there exists a high variability of the channel conditions. In this paper, we consider both the variance and the average of the throughput when deciding the constellation size for adaptive modulation in an OFDM system used for transmitting progressively-coded images with multiple description coding. Simulation results show that in an adaptive modulated image transmission system, taking into account both moments of the throughput achieves better performance than a system considering average throughput alone.

Threshold Evaluation in Link Adaptation Schemes for Progressive Images Transmission

“…Recent works demonstrated that, when the priority of the encoded bitstream is taken into account in the system optimization design, the overall performance can considerably increase. In [10], joint adaptive channel coding and multiple description coding for progressive image transmission over orthogonal frequency division multiplexing (OFDM) systems were investigated both for fixed and for adaptive modulation. Note that, the payload priority was considered in the channel coding across the subcarriers and not in the modulation scheme, which was investigated in [11].…”