Title :
Variable-rate adaptive trellis coded QAM for flat-fading channels
Author :
Lau, Vincent K N ; Macleod, Malcolm D.
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ., Hong Kong
fDate :
9/1/2001 12:00:00 AM
Abstract :
A bandwidth-efficient variable-rate adaptive channel coding scheme, ATCQAM, for time-varying flat-fading channels is proposed. In addition to the forward channel, a low-capacity feedback channel is needed to convey channel state information to the transmitter, possibly with delays and noise. A number of transmission modes, with varying throughputs, are incorporated at the transmitter. Appropriate transmission modes are selected based on the feedback channel states. Design issues for the ATCQAM are considered. A closed-loop control scheme to maintain mode synchronization between the transmitter and the receiver is discussed. The effects of feedback delay, a noisy feedback channel, and mobile speed are investigated. Analytical bounds are derived and simulations are performed to verify the results
Keywords :
adaptive codes; adaptive modulation; channel coding; closed loop systems; fading channels; feedback; land mobile radio; quadrature amplitude modulation; synchronisation; telecommunication control; time-varying channels; trellis coded modulation; variable rate codes; ATCQAM; analytical bounds; bandwidth-efficient variable-rate adaptive channel coding; channel state information; closed-loop control scheme; delays; feedback channel state; feedback delay; flat-fading channels; forward channel; low-capacity feedback channel; mobile speed; mode synchronization; noise; noisy feedback channel; receiver; throughputs; time-varying flat-fading channels; transmission modes; transmitter; variable-rate adaptive trellis coded QAM; Channel coding; Channel estimation; Channel state information; Delay; Fading; Performance analysis; Quadrature amplitude modulation; Radio transmitters; State feedback; Throughput;
Journal_Title :
Communications, IEEE Transactions on
