From the above image, the left side is the E-UTRAN network architecture.
In this tutorial we shall study E-UTRAN network in brief.
EUTRAN will have 2 components:
1. User Equipment [UE]
2. eNodeB
1. User Equipment [UE]
* It is a mobile or a fixed device that is used to connect to the network.
* Specification specified by 3GPP
* Each category has given set of capabilities.
* RAN keeps track of each of the connected UE’s capabilities in order to optimize experience.
2. eNodeB
* Evolved NodeB or E-UTRAN Node B or eNodeB is an element in E-UTRA of LTE.
* It is an evolved version of NodeB in UTRA of LTE. It is a hardware component and is connected to the mobile phone network that communicates directly wirelessly with mobile handsets
* eNodeB is controlled by a Radio Network Controller (RNC).
AIR Interface:
* eNodeB uses the E-UTRA protocols OFDMA (downlink) and SC-FDMA (uplink) on its LTE-Uu interface.
Network Interface:
* eNodeB uses the GTP-U protocol on the S1-U interface with the Serving Gateway (S-GW) for user plane traffic.
* eNodeB uses the X2-AP protocol on the X2 interface with other eNB elements.
* eNodeB uses the S1-AP protocol on the S1-MME interface with the Mobility Management Entity (MME) for control plane traffic.
3. Functions of eNodeB:
* It is responsible for Radio Resource Management. As we know that LTE is flexible with different bandwidth configurations starting from 1.4, 3, 5, 10, 15, 20 MHz. If you have a network with 5MHz bandwidth configuration, you need to optimize and serve all the subscribers.
* eNodeB will manage all the radio resources.
* Synchronization and interface control: Multiple UE will be connected to multiple eNodeB’s. All the management will be taken care by eNodeB.
* MME selection among MME pool: There can be multiple MME’s. eNodeB is responsible for choosing optimized MME.
* Encryption and integrity protection of user data
* IP header compression.
* Routing of user plane data from/to S-GW.