Optimal Transmission of Progressive Sources Based on the Error Probability Analysis of SM and OSTBC

This paper studies the optimal design of multimedia progressive communication systems that are combined with low-complex open-loop multiple-input multiple-output techniques. First, we analyze the behavior of the crossover point of the error probability curves for orthogonal space-time block codes (OSTBC) and spatial multiplexing (SM) with a zero-forcing linear receiver. We mathematically prove that, in the high signal-to-noise ratio (SNR) regime, for both the information outage probability and the uncoded bit error rate, as data rate increases, the crossover point for the error probability monotonically decreases, and the crossover point for the SNR monotonically increases. We prove that this holds, regardless of the numbers of transmit and receive antennas and the spatial multiplexing rate of OSTBC. We next show how those results can be exploited for the optimal transmission of progressive sources, such as embedded image, which require unequal target error rates in their bitstream. That is, the computational complexity involved with the optimal space-time coding of progressive bitstream can be decreased.