Abstract
A range of 5-11.36 kbps videophone codecs are proposed and the 11.36 kbps codec 1, the 8.52 kbps codec 2 and the 8 kbps codec 2a are embedded in the intelligent re-configurable systems 1-3. After sensitivity-matched binary Bose-Chaudhuri-Hocquenghem (BCH) forward error correction (FEC) coding the data rate associated with codec 1 and codec 2a became 20.32 kbps, while that of codec 2 was 15.24 kbps. When using codec 1 in system 1 and coherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSAQAM), an overall signalling rate of 9 kBd was yielded. Over lower quality channels the 4QAM mode of operation had to be invoked, which required twice as many time slots to accommodate the resulting 18 kBd stream. In a bandwidth of 200 kHz, similarly to the Pan-European GSM mobile radio system's speech channel, using systems 1 and 3 for example, 16 and 8 videophone users can be supported in the 16 QAM and 4QAM modes, respectively.
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