there are no book discuss this subject and give you a complete matlab code. I saw some books desctibe the subject supported by Matlab but this is in the DSP only. If you found such a book for the CDMA, please let me know
CDMA toolbox was available some time ago. Mathworks has stopped publishing this blockset. Secondly, if you talking about the same simulink blockset, it is better to called it a Simulink model blockset rather than a GUI
Its actually the Simulink model that has a Graphical User Interaface