Error-rate-based power-controlled multimode H.263-assisted video telephony

The performance of a power-control algorithm suitable for multimode transceivers is investigated using 1, 2, and 4 bit/symbol modems. It is shown that the algorithm is suitable for maintaining a target frame error-rate (FER), irrespective of the modulation mode employed. The transceiver parameters are summarized in Table I, while the minimum and maximum required average transmitted powers in the cell for the different modes are given in Table V. Given the video bit rates of 4.25-16.9 kbps in the various modem modes, the corresponding average video peak signal-to-noise ratio (PSNR) improvement of approximately 6 dB can be inferred from the figure included, where the corresponding PSNR values are approximately 32.5, 35, and 38.5 dB, respectively. This PSNR improvement is achievable in cell areas, where the average transmitted power levels of Table V can be maintained, supporting one of the above legitimate modes of operation of the multimode transceiver.