5G F-OFDM enhances 4G OFDM by improving spectrum efficiency through filtering, enabling higher data ra tes and flexible resource allocation.
1. Core Differences
1.1 OFDM in 4G
4G uses Orthogonal Frequency Division Multiplexing (OFDM) with fixed 15 kHz subcarrier spacing and large guard bands, achieving ~90% spectrum utilization. It lacks dynamic filtering, leading to higher out-of-band e missions.
1.2 F-OFDM in 5G
Filtered-OFDM (F-OFDM) applies time-domain filters to subbands, reducing out-of-band leakage and shrinki ng guard bands. This increases spectrum utilization to up to 98.28% in 100 MHz channels 42.
Spectrum Utilization = (Available Transmission Bandwidth / Channel Bandwidth) × 100%
2. Performance comparison
| Channel BW (MHz) | SCS (kHz) | Technology | Spectrum Utilization (%) |
| 20 | 15 | OFDM (4G) | 90 |
| 20 | 15 | F-OFDM (5G) | 95.4 |
| 100 | 30 | F-OFDM (5G) | 98.28 |
F-OFDM gains 1.08 MHz and 8.28 MHz effective bandwidth over OFDM at 20 MHz and 100 MHz, respectively.
F-OFDM supports scalable numerology (15×2^µ kHz), unlike OFDM’s fixed structure, enabling adaptation to diverse services 1.
3. Summary
F-OFDM outperforms OFDM in spectral efficiency, interference control, and multi-band support, making it essential for 5G’s high-performance demands.