On Alamouti-Encoded 16-APSK in Aeronautical Mobile Telemetry

Alamouti-encoded 16-APSK can solve the two-antenna problem in aeronautical mobile telemetry, but detection and decoding must be performed when the propagation delays from the two transmit antennas are different. The ML sequence estimator is derived for Alamouti-encoded 16-APSK in the presence of a differential delay. The ML estimator requires too many states to be practical. A reduced-complexity sequence estimator is shown to have a BER performance within 1 dB of the single-input/single-output 16-APSK in the AWGN environment.