Question: In 3GPP NR (New Radio) for sequences of length 30 or larger, what type of modulation is applied to the binary sequence to obtain the complex-valued modulation symbols?
Option 1: QPSK (Quadrature Phase Shift Keying)
Option 2: 16QAM (16-ary Quadrature Amplitude Modulation)
Option 3: π/2-BPSK (Pi/2 Binary Phase Shift Keying)
Option 4: GMSK (Gaussian Minimum Shift Keying)
Explanation: The correct answer is π/2-BPSK because, according to the provided context from 3GPP TS 38.211, for sequences of length 30 or larger, the complex-valued modulation symbols are specifically obtained through π/2-BPSK modulation applied to a defined binary sequence. This modulation scheme is notable for its use in certain control channels and its resilience against phase ambiguity, making it suitable for initial synchronization and system information broadcast in NR systems.