Energy Efficient Video Transmission over Fast Fading Channels

With the explosive development of new generation wireless communication technique, the bandwidth is no longer the bottleneck of the wireless video transmission. Energy consumption is the biggest concern now. In this paper, an energy-efficient variable-rate and variable-power modulation method is proposed, which is the optimization of the power and rate of M-QAM signal constellations. Then an adaptive scheme on energy-efficient video transmission over fading channels is proposed. In this scheme, in order to satisfy the requirement with energy efficiency and usage of client/receiver buffer, we implement adaptive selection of modulation level for every video frame, and adaptive power control to compensate the effect by fading channels for every packet. Simulation results show this scheme has good performance on energy saving.</p

Scalar Quantizers with Uniform Encoders and Channel-Optimized Decoders for M-PSK Schemes

In this paper, the problem of index assignments for quantizers with uniform encoders and channel-optimized decoders for M-PSK schemes is studied. The analytical expressions of MSD (Mean-Squared Distortion) for such quantizers with the natural, zigzag and NBC-Gray (NBC: Natural Binary Code) mappings, respectively, have been derived. An interesting result is that at a wide range of MSD levels, the zigzag mapping can offer a significant gain in SNR (Signal to Noise Ratio) over the other two mappings when used in such quantizers, especially when the alphabet size M gets larger, which is agreed by simulation results