Rayleigh BER in Simulink
After the AWGN block you need to divide with the channel coefficient value before you apply the BPSK demodulator. 

If you click on the Rayleigh block it gives the option to enable a "Complex Gain Path Port". You can use this output to accomplish the division mentioned above.

Instead of division you can also multiply the output of the AWGN block with the complex-conjugate of the channel gain.