Advantages of QPSK system:

1. Very good noise immunity.

2. For the same bit error rate, the bandwidth required by QPSK is reduced to half as compared to BPSK.

3. Because of reduced bandwidth, the information transmission rate of QPSK is higher.

4. Variation in OQPSK amplitude is not much .Hence carrier power almost remains constant.

5. Baud rate is half the bit rate therefore more effective utilization of the available bandwidth of the transmission channel.

6. Low error probability.

Due to these advantages the QPSK is used for very high bit rate data transmission.