Tag Archives: ul

Different Categories of UE in LTE

Categories of UE in LTE is divided by its function which is as per below. Functionality: eNB obtains the UE radio capabilities via: • The S1AP initial setup request message • The X2AP in case of handover • The RRC…

Basic Work of WCDMA Physical Channel

A physical channel is defined by a specific carrier frequency, code (scrambling code, spreading code) and relative phase. In UMTS system, the different code (scrambling code or spreading code) can distinguish the channels. Most channels consist of radio frames and time slots,…

DL & UL Physical Channel in LTE

How Physical channel of LTE works in UL & DL?A distinction has to made between:  The Physical channel The Physical signal The DL physical channels are: Physical DL Shared Channel (PDSCH) It is a shared channel used to carry user…

From the Transport to the Physical Channel in LTE

Transport channels are then mapped on the physical channels which are sent over the air interface A CRC is calculated and appended to each TB. It allows the receiver to detect errors. It is used by retransmission mechanisms like H-ARQ…

How Transport Channel Work in LTE?

A transport channel defines how and with what characteristics the information is transmitted. Inherited from the WCDMA, data on the transport channel is organized into “Transport Blocks”, TBs. A Transport block can be transmitted every TTI = 1 ms The…

How Many Logical Channel in LTE ?

The following control logical channels have been defined by the 3GPP: BCCH, Broadcast Control Channel, used for the transmission of system control information. A UE needs to decode it before requesting a connection. PCCH, Paging Control Channel, is a downlink…

Which Bands Used in WCDMA ?

There are different band in different country but most of commonly used band we will discuss here. Main bands : means basic band when 3G commercial launch by Private or public sector. 1920 ~ 1980MHz / 2110 ~ 2170MHz Supplementary bands: different…

How Channel Architecture in LTE?

A Logical Channel is defined by the type of information it carries. Logical channels are classified into control and traffic channels. Answer to the question: what is it being transported? A Transport Channel is defined by how and with what…

How MAC Protocol Work In LTE?

The MAC protocol provides the following services: Logical Channel to Transport channel mapping Scheduling: There is no dedicated channel allocated to a UE. Time and frequency resources are dynamically shared between the users in DL and UL. The scheduler is…

Radio Link Control (RLC) protocol services in LTE

The Radio Link Control (RLC) protocol provides the following services: Segmentation of SDU according to the size Re-Segmentation of PDU Radio Bearer to logical channel mapping Transfer of data in 3 modes: TM Transparent Mode Without retransmission. For real-time service.…

How is Basic Frame Structure in LTE ?

In FDD, the DL and UL Radio Frames (RFs) are not on the same carrier. The RF frame is called Type 1 by the 3GPP. The RF length is 10 ms. The radio frame is made up of 10 sub-frames…

Modulation in LTE

The 3G LTE uses 3 Quadrature Amplitude Modulations (QAMs) depending on the radio quality. QAM uses both the amplitude and the phase. The LTE supports in DL and UL the following modulations: QPSK, the most robust but the less efficient…