Variable-rate coded MQAM for fading channels

Proposes a variable-rate coded modulation technique for narrowband fading channels, where channel state information is available to both the transmitter and receiver. The technique can be applied to either trellis or block codes. The basic premise is to adjust the size of the transmit signal constellation relative to the fade depth via power control. Specifically, channel coding gain is achieved through binary encoding and subset partitioning, while the size of the transmit constellation is adjusted to maximize the data rate. The author presents analytical performance results for the coding technique, and compares it with built-in time diversity coded modulation, which assumes no channel information at the transmitter.