In this work, a spin torque nano oscillator (STNO) device whose frequency can be tuned by Voltage Controlled Magnetic Anisotropy effect (VCMA) is proposed. The requirement of magnetic bias field in previous STNO devices is eliminated by the introduction of VCMA effect. Based on VCMA-STNO, a novel architecture is proposed which can compose of a modulation/demodulation digital frequency shift keying (DFSK) communication system. The proposed architecture utilizes VCMA-STNO as core devices and is much simpler comparing with its CMOS counterpart. The proposed VCMA-STNO modulation/demodulation architecture will help to design next generation spintronics DFSK communication system.