Question

Derive the equivalent discrete-time model of a wireless communication system with quasi-static frequency-selective fading.

Answer 1

The effects of the discect time model of and reciver oversampling on the perfomance of the systems with frequency selective fading with investigated based on tight error perfomance lower bound derived. The effects of diserect time model and recevier oversampling were explicitly expressed in the statical representation of reciver SNR, which is the further qualified in the error probability of bound expression.The convential matched filiter bound can be viewed has special case of perfomace bound derived simulation result showed that the new error probability bound can accuratily predict the perfomance of pratical communication system

Both thertical analysis and numerical examples showed that for a system with spectrum aliasing the perfomance lower bound, which defined the best possible system performance is a periodic funcation of a receiver deserect time signal. For the system without spectrum aliasing, the perfomance of the lower bound. If the effect of spectrum aliasing completely removed at the receiver, then the choice between a fixed recive filiter and statical reciver filiter does not affect system perfomance of the lower bound. Finally we an interesting obserivation the from the numerical examples is that the optimum sampling time of the communication system depends on the power distribution on channel profile and the zero timing offset or desecrite time does not always yield the best system performance