An implantable electrical stimulation system for treating a nerve symptom, the system comprising an implantable device. The implantable devices includes a wave generator that is operable to generate a signal wave and a white noise, mix the signal wave and the white noise, and produce an electrical stimulating signal. The system further comprises an electrode unit located in close proximity to a target nerve and is operable to provide the electrical stimulating signal to the nerve. The system further comprises an external controlling device.