A Narrow-Band Coherent FSK Transmission System Using Phase Rotated Transmit Diversity with Suppression of Envelope Fluctuation

In this paper, we propose a narrow-band coherent FSK transmission system using phase rotated transmit diversity to achieve high-reliability, long-range wireless transmission. The proposed FSK scheme estimates the channel parameters by using the feature that the initial phase of an FSK symbol is uniquely determined, instead of inserting known pilot symbols. The phase rotated transmit diversity scheme reduces the phase discontinuity between the space-time coded FSK symbols, and therefore suppresses any envelope fluctuations. The performance evaluation by computer simulation shows that the proposed scheme improves the transmit power efficiency by about 10 dB compared to conventional STBC. Furthermore, the proposed scheme shows improved performance even in the event of high-speed movement.