SeNB Secondary eNB

SeNB, or Secondary eNB (evolved NodeB), is a concept introduced in 3GPP (3rd Generation Partnership Project) standards for LTE (Long-Term Evolution) and later extended to 5G NR (New Radio) networks. SeNB refers to an additional eNB that can be deployed to enhance coverage and capacity in specific areas or to provide targeted services.

In a typical LTE or 5G network, the eNB serves as the base station that communicates with mobile devices (UEs) and connects them to the core network. However, in certain scenarios, the primary eNB might face limitations in terms of coverage or capacity. To overcome these limitations, a secondary eNB, or SeNB, can be deployed.

Here are some key points to understand about SeNB:

Purpose:

The primary purpose of deploying a SeNB is to enhance the coverage and capacity of the network in specific areas. It can be used to address coverage gaps, improve signal quality in challenging environments, or provide additional capacity in high-density areas.

Operation:

A SeNB operates as an extension of the primary eNB. It connects to the same core network as the primary eNB and follows the same network architecture. The SeNB and primary eNB are interconnected using X2 interface, which allows them to exchange control and user plane data.

Deployment scenarios:

SeNB can be deployed in various scenarios based on the network requirements. Some common deployment scenarios include:

• Coverage enhancement: SeNBs can be placed in areas where the primary eNB's coverage is weak or non-existent. This helps extend the network coverage to reach more users.
• Capacity augmentation: In congested areas with a high number of active users, SeNBs can be deployed to offload traffic from the primary eNB and provide additional capacity. This helps improve the overall user experience and network performance.
• Hotspot coverage: SeNBs can be deployed in specific locations such as stadiums, shopping malls, or convention centers to provide dedicated coverage and capacity for high-density events or areas with a large number of users.

X2 interface:

The X2 interface plays a crucial role in the operation of SeNB. It facilitates communication and coordination between the primary eNB and SeNB. Through the X2 interface, the primary eNB can control and manage the SeNB, allowing them to work together seamlessly.

• Handover support: The X2 interface enables handover procedures between the primary eNB and SeNB. When a user moves from the coverage area of the primary eNB to that of the SeNB, the X2 interface ensures a smooth handover process, maintaining the ongoing communication session.
• Load balancing: The X2 interface allows the primary eNB to distribute the user traffic between itself and the SeNB, enabling load balancing. This helps optimize resource utilization and improves network performance.

Core network integration:

From the core network's perspective, the SeNB appears as an additional eNB, and its integration is similar to that of the primary eNB. The SeNB connects to the core network via the S1 interface, enabling control and data plane communication.

In summary, SeNB (Secondary eNB) is an additional eNB deployed in LTE and 5G NR networks to enhance coverage, capacity, and performance in specific areas. It operates as an extension of the primary eNB, connected through the X2 interface, and provides benefits such as improved coverage, capacity augmentation, and support for seamless handover and load balancing.