OFDMA (Orthogonal Frequency Division Multiple Access):
4G LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) as its multiple access scheme. OFDMA allows multiple users to share the same frequency band by allocating subsets of the frequency band (subcarriers) to individual users.
MIMO (Multiple Input Multiple Output):
Multiple Input Multiple Output technology uses multiple antennas at both the transmitter and receiver ends to improve communication performance. 4G LTE typically uses 2x2 or 4x4 MIMO configurations. MIMO enhances data throughput, reliability, and coverage.
Advanced Modulation:
4G LTE employs advanced modulation techniques like 64-QAM (Quadrature Amplitude Modulation) to encode more data bits per symbol, thereby increasing data rates compared to older 3G technologies.
Low Latency:
4G LTE offers reduced latency compared to previous generations. Lower latency is crucial for real-time applications like online gaming, video conferencing, and autonomous vehicles.
Backward Compatibility:
4G LTE networks are designed to be backward compatible with 3G and 2G networks, ensuring seamless connectivity for devices that support multiple generations of cellular technology.
5G (Fifth Generation)
New Radio (NR):
5G introduces a new air interface called New Radio (NR). NR operates in both sub-6 GHz and mmWave (millimeter wave) frequency bands. The mmWave bands provide significantly higher data rates but have shorter propagation distances.
mmWave Technology:
5G utilizes millimeter-wave frequencies (typically above 24 GHz) for increased bandwidth and data rates. However, mmWave signals have limitations like shorter range and susceptibility to obstructions, requiring advanced beamforming and MIMO techniques for effective deployment.
Massive MIMO:
5G employs Massive MIMO (Multiple Input Multiple Output) technology with a larger number of antennas (e.g., 64x64 or even 128x128 configurations). Massive MIMO enhances spectral efficiency, coverage, and capacity by serving multiple users simultaneously with beamforming techniques.
Low Latency and Ultra-Reliable Communication (URLLC):
5G aims to provide ultra-low latency (as low as 1 ms) and ultra-reliable communication for applications like augmented reality, autonomous vehicles, industrial automation, and remote surgery.
Network Slicing and Edge Computing:
5G introduces network slicing, allowing operators to create multiple virtual networks with customized characteristics (e.g., latency, bandwidth) to cater to diverse use cases. Additionally, edge computing capabilities in 5G networks enable data processing closer to the end-users, reducing latency and enhancing application performance.
Enhanced Spectrum Efficiency:
5G employs advanced modulation schemes (e.g., 256-QAM and beyond), wider bandwidth channels, and sophisticated coding techniques to achieve higher spectral efficiency and data rates compared to 4G LTE.
