On the Distortion SNR Exponent of Hybrid Digital–Analog Space–Time Coding Academic Article uri icon


  • We consider the transmission of a real independent and identically distributed (i.i.d.) "analog" source over a quasi-static M-input N-output multiple-input multiple-output (MIMO) block-fading channel. The relevant performance criterion is end-to-end average quadratic distortion D versus channel signal-to-noise ratio (SNR), for given spectral efficiency η, defined as the ratio of the source bandwidth over the channel bandwidth. In the limit of high SNR, we define the distortion SNR exponent a*(η) as the largest a such that D = snr-a, over all possible source-channel coding schemes of spectral efficiency η. We find a simple upper bound on a *(η), an achievable lower bound asep(η) achievable by separated (tandem) source-channel coding, and a tighter lower bound ahybrid (η) achievable by new hybrid digital analog space-time coding schemes. As a corollary, we have that a*(η) is completely determined for the scalar case M = N = 1 and for the "bandwidth compression" case η ≥ 2 min{M,N}. Explicit and simple construction of hybrid space-time codes achieving ahybrid(η) are also given. © 2007 IEEE.

author list (cited authors)

  • Caire, G., & Narayanan, K.

citation count

  • 73

publication date

  • August 2007