Power-distortion optimized mode selection for transmission of VBR videos in CDMA systems

A power-distortion (P-D) optimized coding modeselection scheme is proposed for variable bit rate videos in wireless code-division multiple-access (CDMA) systems. Unlike the conventional rate-distortion (R-D) optimized mode-selection methods, the proposed scheme takes into account time-varying channels. We show that the proposed optimization problem can be represented as the conventional R-D mode-selection problem, in which the Lagrangian multiplier depends on the channel conditions. In the proposed scheme, as the link gain of a user increases, the optimum mode for the user tends to be intramode rather than intermode, and vice versa. Numerical results show that, in CDMA systems, the proposed scheme consumes much less power at the same image quality compared with conventional R-D schemes.