The LTE Radio Access Network (RAN) consists of the eNodeB (the Base Station), and its interfaces and network elements connected to the core network. In 3GPP Release 8 standards, operators have specific requirements for simplifying eNodeB deployment and reducing operational cost, resulting in the concept of Self-Optimized Networks (SONs).
The eNodeB provides wireless mobile connectivity between the user device and the Evolved Packet Core. It’s connected to the EPC via the S1 interface (S1 to MME or S1-S-GWs) or to another eNodeB via the X2 interface. The eNodeB is defined by 2 separate components, the radio unit and the digital unit. The functions of the eNodeB include:
- Radio resource management: Radio bearer control, radio admission control, and connection
- Mobility control: Dynamic allocation of resources to UE in both the uplink and downlink (scheduling)
- IP header compression and encryption of user data stream
- Selection of an MME at UE attachment when no routing to an MME can be determined from the information
- Routing of user plane data toward the S-GW
- Scheduling and transmission of paging messages (originated from the MME)
- Scheduling and transmission of broadcast information (originated from the MME or O&M)
- Measurement and measurement reporting configuration for mobility and scheduling
- Scheduling and transmission of ETWS messages (originated from the MME)
For more information, see:
http://www.mindcommerce.com/Publications/SON_ChallOpp_2014.php
