5G Waveforms and Modulation
- [The University of Chicago]
- Overview
5G uses a flexible Orthogonal Frequency-Division Multiplexing (OFDM) based approach for its waveform, but it also supports advanced waveforms like Filtered OFDM (F-OFDM), Filter Bank Multicarrier (FBMC), and Universal Filtered Multicarrier (UFMC) to meet diverse performance requirements.
For modulation, 5G supports multiple schemes, including QPSK, 16-QAM, 64-QAM, and 256-QAM, allowing for higher data rates when signal conditions are good.
1. 5G Waveforms:
- OFDM: The baseline for 5G New Radio (NR) is a flexible version of OFDM, which divides data into multiple parallel subcarriers. Unlike in previous generations, 5G NR supports flexible subcarrier spacing to adapt to different bandwidths and frequencies.
- F-OFDM: Filtered OFDM enhances spectral confinement by filtering in subbands, which helps reduce out-of-band emissions.
- FBMC: Filter Bank Multicarrier is a candidate waveform that uses a bank of filters for each subcarrier, allowing for more localized subcarriers and potentially better spectral efficiency.
- UFMC: Universal Filtered Multicarrier applies filtering to subbands, reducing out-of-band emissions while remaining compatible with low-latency applications.
2. 5G Modulation Schemes:
- QPSK: Quadrature Phase Shift Keying uses four phase states to represent data.
- 16-QAM: 16-Quadrature Amplitude Modulation uses a combination of phase and amplitude to represent 16 different states, enabling higher data rates than QPSK.
- 64-QAM: Transmits more bits per symbol than 16-QAM, allowing for higher throughput.
- 256-QAM: The highest-order modulation scheme used, it can transmit 8 bits per symbol, resulting in the highest data rates, but it requires a strong signal with low noise to be effective.
[More to come ...]
