enodeB functions

enodeB is responsible for radio transmission between UE and enodeB

Functionality of eNodeB

• Radio resource Management(RRM) in general
• Admission control
• Radio bearer control
• Scheduling of user data
• Control signaling over the air interface
• Ciphering of user data over the air interface
• IP packet header compression  over the air interface
• MME selection when no routing to an MME can be determined from information provided by the UE

The are covered by a single enodeB is split into one or more typically 3 cells.enodeB is directly connected to the core network using S1 interface. A new interface X2 interface has been  defined between enodeB, and all the other enodeB's and all of them may be possibility linked together. The main purpose if this interface is to  reduce packet loss during handovers.As the UE moves across the access network, unsent or unacknowledged packets that are stored in the old enodeB queues can be forwarded or tunneled to new enodeB.

From a high level perspective,

The new E-UTRAN architecture is moving towards WLAN networks

LTE-enodeB is partitioned into following categories

1.Radio
2.Physical layer
3.Protocol stack application
4.Customizable digital front end.

Enode B PHY-highlights

> OFDMA in DL and SC-FDMA in UL
> Duplexing schemes ( Full/ half duplex FDD , TDD)
> Scalable channel bandwidth 20 Mhz
> MIMO processing with 2x2 Up-link and 4x4 down-link antennas
> Adaptive modulation and coding ( QPSK, 16 QAM and 64 QAM fro down-link )
> Two radio frame structures

                Type -1 : Full and half duplex FDD

                Type-2 : TDD