Bit error simulation of FSK, BPSK, and pi/4 DQPSK in flat and frequency-selective fading mobile radio channels using two-ray and measurement- based impulse response models

A software simulation tool has been developed to simulate the performance of digital mobile radio systems in fading channels. The simulation tool generates average bit error rate (BER) and bit-by-bit error patterns with user-specified parameters. The simulation tool can simulate various communication system parameters (i.e. modulation scheme, data rate, signal to noise ratio, and receiver speed, etc.) and different channel environments (i.e. outdoor and indoor fading channels). Additive white Gaussian noise and co-channel interference effects for outdoor channels are also simulated. Using the simulation tool, we studied average BER results for FSK, BPSK, and Ï /4 DQPSK with Nyquist pulse shaping in indoor and outdoor, flat and frequency-selective fading channels. The BER performance of Ï / 4 DQPSK using the data rate and the pulse shaping requirement in the U.S. Digital Cellular Standard are studied. BER results for high data rate (> 450 kbps) transmissions in indoor channels generated by a measurement-based channel model, SIRCIM, are compared with results in channels generated by the classic two-ray Rayleigh fading model. Simulation results show that irreducible BER is not only a function of rms delay spread, but is also a function of the temporal and spatial distribution of multipath components. The simulation results are also applied into a real-time bit-by-bit error simulation using a hardware simulator between a data source and a data sink. Simulation results of the transmission of a video image in mobile radio fading channels are shown. This simulation methodology allows subjective evaluation of link quality between a source and sink in a laboratory in real-time without the need of building radio frequency hardware.