Error-rate-based power-controlled multimode H.263-assisted videotelephony

摘要

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