rayleigh channel is the basic channel model. The preferred ones are Ricean and Nakagami which offer more flexibility. Rayleigh has a single parameter, teh nakagami and rice have tow parameters and can more closely correlate to a fading channel. e.g. r(t)= a+b*e(-j2pift) has an attenuation component "a" and a multipath factor b which enables a rice or nakagami model to fit better, a particular caseof the Nakagami model is the Rayleigh dist.
Nevertheless, the rayleigh model offers a close approximation when the attenuation is uniform i.e. is averaged out.
BPSK is a simple modulation scheme, and is not the preferred but is preferred option for academic study since it is the easiest. e.g. if I use QPSK or 8PSK or better 16QAM or GMSK I have different issue to deal with.
There are plenty of good resources on comm available to start with wikipedia, digi commuincation by sklar or by mk simon or proakis or simon haykin..are some basic references.