Real-time simulation of randomly time-variant linear systems: the mobile radio channel

In this paper, the simulation of the QWSSUS channel is considered. The paper begins with an analytical description of the problem, it then briefly reviews previous approaches to the hardware simulation of the wideband frequency, selective mobile radio channel, and describes a highly versatile and compact digital architecture for the accurate simulation of this channel. A bandpass RF input signal is translated to an IF of 5 MHz, sampled digitally, quadrature demodulated, and processed to simulate the effect of the mobile radio propagation environment, whereupon the baseband quadrature components are digitally quadrature modulated onto a 5 MHz carrier, converted to analog, filtered, and translated to the RF band. The digital processing, performed by the TMS32050 and IMSA110 integrated circuits, is demonstrated to be highly versatile and flexible. The use of the system for both stored channel and synthetic channel simulation is considered. Experimental results are provided to support the key claims