Abstract
A novel transmission scheme called fully generalised spatial modulation (FGSM) is proposed for underwater communication, where any subset of available transmitting antennas (N-t) is activated at a time instant to transmit the data constellation symbol and the index of the active antenna is also harnessed to carry information. The FGSM offers better energy efficiency (EE) than previous spatial modulation (SM) and generalised SM systems. The proposed FGSM system is tested in an acoustic underwater multipath channel. Simulation results show that it can significantly improve the average bit error rate (ABER) as well as EE.