Hi everboy: I am now doing a final year project in order to complete the degree study.  The project is about the Simulation of WCDMA system.The _object_ive is study the performance of the system over AWGN and Multipath Rayleigh Fading. I face some problem during simulation. Hope anyone will give me an idea and solution.  thanks.Below are my problems: AWGN: In this block diagram, i only can run the simulation for single user only. Between, i also want to run for multiusers such as 10, 40, and 100 users. I had tried to use varian from mask in the mode AWGN, but the graph BER vs SNR show a straight line. I wonder why. Varian represent the number of users and can be calculated using formula varian=(k-1)0.05 where k is number of user. Thus, how i can run simulation for multiusers. any idea or should add any other block to represent the users? Multipath Rayleigh Fading. Multipath rayleigh is the speed of the mobile /vehicular. The speed i chose is 5km/h, 60km/h, 90km/h and 120km/h. It is done for single user. The maximum dopple shift is =[(frequency x speed)/3x10power  of 8] like [(5km/3600s) x 2GHz] / 300 000 000. For  simulation of 5km/h, the graph is When SNR increase the BER will decrease. but, it is different for graph 60km/h, 90km/h and 120km/h.The graph obtained were when the SNR increase the BER increase too. This is not the desired graph. As i know, when the SNR increase the BER will decrease, am i right.? Although i using same parameter as in 5km/h, i wonder why the BER is increase. do anyone, got any idea, or what should i change in the parameter.? i have attach the awgn and multipath block diagram on the web below: http://www.esnips.com/web/siatsWebResearch i hope anyone can give me a help, an idea or solution for the problem. For your kindness help, i sincerely thanks. shirly