Further Results on the SNR Exponent of Hybrid Digital Analog Space Time Codes

We consider the transmission of a real i.i.d. Gaussian source over a quasi-static MIMO fading channel. The relevant performance criterion is end-toend average quadratic distortion D versus channel SNR, for given spectral efficiency η, defined as the ratio of the source bandwidth over the channel bandwidth. In the limit of high-resolution (vanishing distortion) for high-SNR, we define the distortion SNR exponent a(η) for a family of source-channel coding schemes as the a = − log D/ log snr. In our recent paper [1], we have computed upper and lower bounds on a(η) for the MIMO channel. Here, we first extend these to the parallel channel. Using these results, we propose a hybrid digital analog scheme that achieves the same exponent a(η) as the schemes in [1] for the 2x2 MIMO channel for η < 2M . I. SPACE-TIME CODING AND END-TO-END