A wireless digital transmission scheme is using 16-QAM over an additive white Gaussian noise channel ...
Given Information
- Modulation scheme: 16-QAM
- Bit rate: Rb = 4 × 106 bits/sec
- Channel: Additive White Gaussian Noise (AWGN)
- Receiver: Maximum-Likelihood Receiver
Step 1: Calculate Bits per Symbol
For M-ary QAM, the number of bits transmitted per symbol is:
Bits per symbol = log2(M)
= log2(16) = 4 bits/symbol
Step 2: Calculate Symbol Rate
Symbol rate is calculated by dividing the bit rate by the number of bits per symbol.
Rs = Rb / log2(M)
= (4 × 106) / 4
= 106 symbols/sec
Step 3: Calculate Minimum Bandwidth
For ideal Nyquist transmission with zero roll-off factor:
Bmin = Rs
= 106 Hz
= 1 MHz
Final Answer
1.00 MHz
Minimum transmission bandwidth required
Note: AWGN and maximum-likelihood detection do not change the minimum Nyquist bandwidth. The calculation assumes ideal zero-roll-off pulse shaping.
