On Simplification of Ray Tracing Channels in Radio Channel Emulators for Device Testing

Emulation of ray tracing (RT) simulated and measured channels in radio channel emulators is seen as a key enabler for virtual drive testing (VDT). Limitations in emulator hardware resources require that RT simulated or measured channels are simplified. In this preliminary study, the impact of channel simplification is investigated with a target of minimizing the error of the mean delay. The increase in the number of taps in the channel model caused by tap splitting in the conventional constant mean delay method proposed in the literature is addressed by considering the radio frequency (RF) bandwidth of the channel emulator. Although this approach is not optimal, it uses on average 8 taps compared to 24 taps and 36 taps in the original and the tap aligned channels with a constant mean delay, respectively.