Do BPSK vs QPSK have the same performance?

BPSK and QPSK have the same BER performance under additive white Gaussian noise only if the symbols are appropriately mapped to bits (such as Gray coding) since they can be viewed / treated as two independent BPSK signals that can share the same frequency due to their orthogonality (quadrature carrier).

1. Why is BPSK better than QPSK?
2. Is BPSK and QPSK same?
3. Why is BPSK and QPSK the same?
4. Which has more bandwidth QPSK or BPSK?

Why is BPSK better than QPSK?

BPSK is considered to be robust modulation scheme compare to the QPSK as it is easy in the receiver to receiver the original bits. After passing both BPSK and QPSK through channel and noise, in the BPSK demodulator only two decision points are required to retrieve the original binary information.

Is BPSK and QPSK same?

Two common examples are "binary phase-shift keying" (BPSK) which uses two phases, and "quadrature phase-shift keying" (QPSK) which uses four phases, although any number of phases may be used.

Why is BPSK and QPSK the same?

The probability of error is identical for BPSK and QPSK because the BER has been measured in terms of signal to noise ratio per bit.

Which has more bandwidth QPSK or BPSK?

Quadrature phase-shift keying (QPSK).

In comparison to OOK and BPSK, QPSK enables the data rate to be doubled while keeping the same bandwidth, meaning it's also possible to stay at the same data rate at half the bandwidth, with the same bit error ratio (BER). So QPSK is suitable for data rates of 100 Gbps as well.