Why BPSK is used?

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 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).

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.