Training Structure Design Optimization for Continuous Time-Varying Fading Channels

In fast-varying faded channels the transmission can be organized into frames where the channel estimation is mainly training-based. For fast-varying fading channels the training length and training interval can be optimized jointly to maximize the throughput. The optimal balance of training and payload depends on the combination of Doppler frequency and frame length. Here we show that, depending on the degree of mobility for large enough signal to noise ratio, there is a definite advantage in fragmenting the frame with dispersed segments of training symbols of smaller length rather than having a highly reliable channel estimate by concentrating all the training symbols at the beginning of the frame.