LTE (Long-Term Evolution) introduces Quality of Service (QoS) to ensure that different types of traffic receive appropriate treatment in terms of priority and resource allocation. To achieve this, LTE defines QoS Class Identifiers (QCIs) that classify traffic into different classes. Each QCI represents a specific level of service that is suitable for different types of applications. Let’s explore the LTE QCI classes in detail:
1. QCI Class Identifier:
- Definition: QCI is a numeric identifier assigned to a specific class of QoS for user plane traffic in LTE networks. It ranges from 1 to 9, and each QCI corresponds to a particular set of QoS characteristics.
- Key Function: QCIs are used to differentiate between various traffic types and assign appropriate QoS parameters to ensure optimal performance.
2. QCI Classes:
- QCI 1 – Conversational Voice:
- Description: This class is optimized for conversational voice services, such as Voice over LTE (VoLTE).
- Characteristics: Low latency, low packet loss, and high reliability are prioritized to ensure clear and real-time voice communication.
3. QCI 2 – Conversational Video:
- Description: Designed for conversational video services, ensuring a smooth and high-quality video calling experience.
- Characteristics: Moderate latency, low to moderate packet loss, and sufficient bandwidth for video streaming.
4. QCI 3 – Real-Time Gaming:
- Description: Optimized for real-time gaming applications to provide a responsive and low-latency gaming experience.
- Characteristics: Low latency, moderate packet loss, and sufficient bandwidth to support real-time gaming requirements.
5. QCI 4 – Non-Conversational Voice, Video, and Signaling:
- Description: Suitable for non-conversational voice and video services, as well as signaling traffic.
- Characteristics: Moderate latency, moderate packet loss, and reliable signaling for services like push-to-talk.
6. QCI 5 – IMS Signaling:
- Description: Dedicated to IMS (IP Multimedia Subsystem) signaling traffic.
- Characteristics: Prioritizes signaling messages for IMS services, ensuring efficient communication between network elements.
7. QCI 6 – FTP, P2P, and Large File Transfer:
- Description: Geared towards traffic generated by file transfer applications like FTP and peer-to-peer (P2P) services.
- Characteristics: Supports higher latency tolerance and is optimized for efficient transfer of large files.
8. QCI 7 – Remote Desktop and Online Gaming:
- Description: Tailored for applications like remote desktop access and online gaming.
- Characteristics: Balances latency and reliability to provide a responsive experience for interactive applications.
9. QCI 8 – Online Gaming and File Sharing:
- Description: Designed for online gaming and file sharing services.
- Characteristics: Prioritizes responsiveness and moderate reliability for interactive applications and file transfers.
10. QCI 9 – QoS Insensitive Data:
- Description: Used for applications with lower sensitivity to QoS parameters, such as bulk data transfer.
- Characteristics: Provides best-effort service with no specific QoS guarantees, suitable for less time-sensitive applications.
Conclusion:
LTE QCI classes play a vital role in ensuring that different types of traffic receive the appropriate level of service based on their specific requirements. By assigning QCIs, LTE networks can prioritize traffic for applications like voice calls, video streaming, online gaming, and file transfers. This helps in optimizing resource allocation, reducing latency, and delivering a better overall user experience across diverse communication services in LTE networks.