Practical results for a generic modem using linear mobile radio channels

To date, the majority of work on reference-based sounding techniques, whether targeted towards reference tone insertion or reference symbol insertion, has been based on simulations. In the present work, however, measured performance data are presented for one of the techniques-a reference tone based 16-QAM (quadrature amplitude modulation) system. It is shown that the claims made based on simulation results are indeed borne out in practice, with the reference approach overcoming the irreducible error rate phenomenon in fading and permitting coherent detection and simple symbol timing for complex multilevel modulation systems. A reference-based 16-QAM system is shown to have approximately 2-dB-2.5-dB implementation loss over the theoretically optimum 16-QAM performance, based on real hardware implementation, which, viewed in conjunction with the low complexity of implementation. presents a realistic and viable solution to, high-rate data transmission in a hostile mobile environment