Question: What is the primary multiple access scheme used for the NR (New Radio) physical layer, and what additional scheme is specifically supported for uplink?
Option 1: Code Division Multiple Access (CDMA) with an additional support of Frequency Hopping Spread Spectrum (FHSS) for uplink
Option 2: Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP), and Discrete Fourier Transform-spread-OFDM (DFT-s-OFDM) with a CP specifically for uplink
Option 3: Time Division Multiple Access (TDMA) with an additional support of Space Division Multiple Access (SDMA) for uplink
Option 4: Frequency Division Multiple Access (FDMA) alone for both downlink and uplink
Explanation: The correct answer, OFDM with a cyclic prefix (CP) for general use and DFT-s-OFDM with a CP specifically for uplink, highlights the NR physical layer's adaptability to efficiently utilize spectrum resources. OFDM is chosen for its robustness against multipath fading, while DFT-s-OFDM is particularly beneficial for uplink due to its ability to reduce Peak-to-Average Power Ratio (PAPR), enhancing mobile device power efficiency. This combination supports the flexible duplexing schemes (FDD and TDD) and various spectrum allocations, underscoring the NR's design for versatile and efficient wireless communication.