Which wireless technique reduces interference and increases channel robustness in 4G and 5G networks?

Which wireless technique reduces interference and increases channel robustness in 4G and 5G networks?

• A. MIMO-OFDM
• B. FH-CDMA
• C. DSSS
• D. 802.11n

Answer: (A)

The combination of multiple antennas and orthogonal subcarriers—MIMO-OFDM—provides the level of interference reduction and channel robustness needed in 4G and 5G networks. MIMO uses several antennas at the transmitter and receiver to create multiple paths for the signal, improving reliability through diversity and increasing data throughput via spatial multiplexing. OFDM breaks the available spectrum into many narrow, orthogonal subcarriers, which mitigates intersymbol interference caused by multipath and makes the channel easier to equalize. Put together, MIMO-OFDM lets cellular systems maintain strong, reliable links even in crowded or multipath-rich environments, boosting both resilience to interference and overall capacity. By contrast, the other options belong to different radio paradigms or technologies: frequency-hopping CDMA and direct-sequence DSSS are spread-spectrum techniques not specific to 4G/5G cellular design, and 802.11n is a Wi‑Fi standard, not a cellular standard, though it uses similar ideas.

The combination of multiple antennas and orthogonal subcarriers—MIMO-OFDM—provides the level of interference reduction and channel robustness needed in 4G and 5G networks. MIMO uses several antennas at the transmitter and receiver to create multiple paths for the signal, improving reliability through diversity and increasing data throughput via spatial multiplexing. OFDM breaks the available spectrum into many narrow, orthogonal subcarriers, which mitigates intersymbol interference caused by multipath and makes the channel easier to equalize. Put together, MIMO-OFDM lets cellular systems maintain strong, reliable links even in crowded or multipath-rich environments, boosting both resilience to interference and overall capacity. By contrast, the other options belong to different radio paradigms or technologies: frequency-hopping CDMA and direct-sequence DSSS are spread-spectrum techniques not specific to 4G/5G cellular design, and 802.11n is a Wi‑Fi standard, not a cellular standard, though it uses similar ideas.