/ˌɛs siː ˌɛf ˌdiː ˈeɪ.mə/
noun — "the uplink method that saves mobile power while sharing frequencies efficiently."
SC-FDMA, short for Single-Carrier Frequency-Division Multiple Access, is a wireless communication technique that combines the low peak-to-average power ratio (PAPR) of single-carrier systems with the multi-user capabilities of OFDMA. It is primarily used in the uplink of LTE (LTE) and 5G-NR (5G-NR) networks to improve power efficiency in mobile devices while maintaining spectral efficiency.
Technically, SC-FDMA transforms time-domain input symbols into frequency-domain representations using a Discrete Fourier Transform (DFT), maps them onto subcarriers, and then converts back to the time domain via an Inverse Fast Fourier Transform (IFFT). This preserves the single-carrier structure, reducing PAPR compared to conventional OFDMA, which is advantageous for battery-powered devices. Multiple users are allocated distinct subcarrier blocks, enabling simultaneous uplink transmissions with minimal interference.
Key characteristics of SC-FDMA include:
- Low PAPR: reduces power amplifier stress and improves mobile device efficiency.
- Frequency-domain multiple access: allows multiple users to share the same frequency band.
- Uplink optimization: designed for mobile-to-base-station transmissions.
- Compatibility: integrates seamlessly with LTE and 5G-NR uplink protocols.
- Spectral efficiency: maintains high throughput and minimizes interference.
In practical workflows, SC-FDMA enables smartphones and IoT (IoT) devices to transmit data efficiently to cellular base stations. Network engineers allocate subcarrier blocks dynamically based on user demand and channel conditions, balancing power consumption and throughput. Its low PAPR characteristic is especially valuable for maintaining long battery life in mobile devices while supporting high data rates.
Conceptually, SC-FDMA is like sending multiple trains on parallel tracks where each train has a smooth, consistent speed, reducing engine strain while efficiently carrying passengers (data) to the station.
Intuition anchor: SC-FDMA optimizes uplink transmissions, making wireless communication energy-efficient without sacrificing multi-user performance.