Optimizing end-to-end distortion in MIMO systems

A significant amount of recent research has focused on characterizing the diversity-multiplexing tradeoff region in multiple antenna wireless systems. In this paper we focus on finding the point on this diversity-multiplexing region that minimizes an end-to-end distortion measure. Our goal is to find the optimal balance between the increased data rate provided by multiplexing versus the error protection provided by diversity. We first present analytical results for the distortion achieved by concatenating a vector quantizer with a MIMO channel. We show that in the high SNR regime we can find a closed form expression for the end-to-end distortion as a function of the optimal point on the diversity-multiplexing tradeoff curve. We also show that this framework can be used to minimize end-to-end distortion for a broad class of source and channel codes. We demonstrate this with a non-asymptotic example using progressive video encoding and space-time channel codes. Finally, we summarize a methodology for incorporating delay into the end-to-end distortion model and solving for the optimal tradeoff between diversity, multiplexing, and delay.