Explanation: Of all the modulation showed, QAM is the most bandwidth efficient one.
Which modulation is most efficient?
For such optical links, the BPSK format are often believed to be the most power efficient one—i.e., the modulation format requiring the lowest signal-to- noise ratio (SNR) per bit to reach a given bit error rate (BER).
Which band is more efficient?
4. Which is more bandwidth efficient? Explanation: Time hopping spread spectrum is more bandwidth efficient.