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Radio Bearer in LTE

Radio Bearer in LTE In Long-Term Evolution (LTE) wireless communication, a “Radio Bearer” serves as a crucial link between the user equipment (UE) and the evolved NodeB (eNodeB), facilitating the exchange of data. Radio Bearers are classified into two main categories: Control Radio Bearers (CRBs) and Data Radio Bearers (DRBs). CRBs are responsible for transmitting … Read more

LTE Frame Structure and Resource Block Architecture

LTE Frame Structure The figure below shows the LTE frame structure under Time division mode (TDD) Type 2 and Frequency Division mode (FDD) Type 1. Differences in LTE Frame Structure Main differences in LTE Frame Structure between the two modes are Frame 0 and frame 5 (always downlink in TDD) Frame 1 and frame 6 … Read more

What is EPS Bearer in LTE?

Eps bearer LTE EPS is a connection-oriented transmission network and, as such, it requires the establishment of a “virtual” connection between two endpoints (e.g. a UE and a PDN-GW) This virtual connection is called an “EPS Bearer” It provides a “bearer service”, i.e. a transport service with specific QoS attributes. The LTE QoS parameters associated … Read more

Downlink Power control in LTE

The eNodeB determines the downlink transmit energy per resource element (lte epre). Downlink cell-specific reference-signal (RS) lte epre is constant across the downlink system bandwidth and constant across all subframes until different cell-specific RS power information is received. The downlink RS lte epre is given by the parameter Reference-signal-power provided by higher layers. In cases 16QAM, 64QAM, … Read more

What is AMC & its Algorithm in LTE

The effective Eb/No and hence the spectral efficiency depend on BLER. However there are QoS requirements which also have to be considered. Taking both into account leads to a target BLER. AMC is in use in order to tune BLER so that the target value is reached. Therefore when channel conditions change modulation and/or coding … Read more

Transmit Diversity & Receive Diversity

Transmit Diversity MISO = Multiple Input Single Output Principle More complex than SISO. 2 or more transmitters and one receiver. MISO is more commonly referred to as transmit diversity. The same data is sent on both transmitting antennas but coded in such a way that the receiver can identify each transmitter. Benefits Transmit diversity increases … Read more

LTE Downlink Logical Channel

Paging Control Channel(PCCH) A downlink channel that transfers paging information and system information change notifications. This channel isused for paging when the network does not know the location cell of the UE Broadcast Control Channel (BCCH) Provides system information to all mobile terminals connected to the eNodeB. A downlink channel for broadcasting system control information … Read more

Intra E-UTRAN Handover in LTE

The UE is RRC connected. During the HO: The radio link is released from the eNodeB 1 and re-established on the eNodeB 2 The Control plane is switched to the eNodeB 2 and the MME The User plane is switched to the eNodeB 2 and the S-GW The Intra-e-UTRAN-Access Mobility Support for UEs in ECM-CONNECTED … Read more

MIMO Single User for LTE

SU-MIMO = Single User MIMO It is the most common form of MIMO. Each user is served by only one BS and it occupies the resource exclusively, including time, frequency. It can be applied in the uplink or downlink. But it is generally applied only in DL. The UE can easily have 2 antennas in … Read more

Random Access Procedure in LTE

When the UE has obtained system information, it has to request an RRCconnection. Like it has no dedicated resources, the UE requests the connection using the Random Access Procedure using common uplink resources.  At the end of the procedure, the UE is RRC connected UE and eNodeB are able to exchange data using dedicated radio … Read more