QPSK constellation diagram

As mentioned above in the table, BPSK represents binary input 1 and 0 w.r.t. change in carrier phase by 180 degree. While QPSK represents two bits using complex carrier symbol each having 90 degree shift with one another .

BPSK Applications It is used in OFDM and OFDMA to modulate the pilot subcarriers used for channel estimation and equalization . As we know different channels are used for specific data transmission in cellular systems.

BPSK can be considered as a form of amplitude shift keying where each nonreturn to zero (NRZ) data bit of value 0 is mapped into a −1, and each NRZ 1 is mapped into a + 1. The resulting signal is then passed through a filter to limit its bandwidth and then multiplied by the carrier signal cos ωt (see Figure 4.2).