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4G (LTE - Long Term Evolution)

1. OFDMA (Orthogonal Frequency Division Multiple Access):

  • 4G LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) for downlink transmission.
  • OFDMA allows multiple users to be served simultaneously by assigning different sub-carriers in the frequency domain to different users.
  • This improves efficiency and throughput.

2. MIMO (Multiple Input Multiple Output):

  • MIMO technology is used in 4G to improve spectral efficiency and link reliability.
  • Multiple antennas are used at both the transmitter and receiver ends to transmit and receive multiple data streams simultaneously over the same frequency channel.
  • This results in increased data rates without requiring additional bandwidth.

3. Advanced Modulation Techniques:

  • 4G employs advanced modulation techniques like 64-QAM (Quadrature Amplitude Modulation) for uplink and 256-QAM for downlink.
  • These modulation techniques enable higher data rates by encoding more bits per symbol.

4. LTE-Advanced:

  • LTE-Advanced is an enhancement of the 4G LTE standard that introduced features like carrier aggregation, which allows the combination of multiple LTE carriers to increase bandwidth and data rates.
  • Other features include enhanced MIMO schemes, interference management techniques, and improved radio resource management.

5G (NR - New Radio)

1. mmWave (Millimeter Wave) Frequencies:

  • 5G introduces the use of higher frequency bands, including mmWave frequencies (typically above 24 GHz).
  • These higher frequency bands offer larger bandwidths, enabling higher data rates and capacity.
  • However, mmWave signals have shorter propagation distances and are more susceptible to blockages, requiring advanced antenna technologies and beamforming techniques.

2. Massive MIMO:

  • 5G incorporates Massive MIMO technology, which uses a large number of antennas at the base station to serve multiple users simultaneously.
  • Massive MIMO enhances spectral efficiency, increases capacity, and improves network coverage and reliability.

3. OFDM (Orthogonal Frequency Division Multiplexing):

  • Similar to 4G LTE, 5G also uses OFDM for data transmission.
  • However, 5G introduces a more flexible OFDM framework, allowing for scalable numerology and sub-carrier spacing to support diverse use cases and deployment scenarios.

4. Network Slicing and Virtualization:

  • 5G enables network slicing, which allows the creation of multiple virtual networks on a shared physical infrastructure.
  • This enables customization and optimization of network resources for specific applications and services, such as IoT, ultra-reliable low-latency communication (URLLC), and enhanced mobile broadband (eMBB).

5. Low Latency and URLLC:

  • 5G aims to significantly reduce latency, enabling real-time communication and applications like autonomous driving, remote surgery, and augmented reality/virtual reality (AR/VR).
  • The introduction of URLLC (Ultra-Reliable Low-Latency Communication) in 5G ensures reliable and low-latency communication for critical applications and services.

4G LTE focuses on enhancing data rates, capacity, and efficiency using technologies like OFDMA and MIMO, 5G NR introduces new features and capabilities, such as mmWave frequencies, Massive MIMO, network slicing, and low latency, to support diverse use cases and applications in the era of the Internet of Everything (IoE).