UE categories in LTE These UE categories are often referred to as UE classes. The low end UE does not support MIMO but the high end UE will support 4×4 MIMO Whatever category a UE belongs to, it has to be capable of receiving transmissions from up to four antenna ports. This is because the … Read more
In LTE (Long-Term Evolution), traffic operations involve the management of data traffic within the network, ensuring efficient communication between User Equipment (UE) and the Evolved Packet Core (EPC). Here’s an overview of traffic operations in LTE: Data Transmission: LTE supports high-speed data transmission, enabling a variety of services such as web browsing, video streaming, and … Read more
The QoS Class Identifier (QCI) is a scalar that is used as a reference to access node-specific parameters that control bearer level packet forwarding treatment (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.). The Allocation and Retention Priority (ARP) primarily allows one to decide whether a bearer establishment request can … Read more
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 data, radio & core network, system information (BCH), paging message. Physical DL Control Channel … Read more
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 Depending on the Transport Format and … Read more
Spreading consists of 2 steps: Channelization operation, which transforms data symbols into chips Scrambling operation is applied to the spreading signal Spreading means increasing the bandwidth of the signal beyond the bandwidth normally required to accommodate the information. The spreading process in UTRAN consists of two separate operations: channelization and scrambling. The first operation is … Read more
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 “Transport Format”, TF, defines how the blocks can be … Read more
How Spreading & Dispreading in WCDMA-3G ? Traditional radio communication systems transmit data using the minimum bandwidth required to carry it as a narrowband signal. CDMA system mix their input data with a fast spreading sequence and transmit a wideband signal. The spreading sequence is independently regenerated at the receiver and mixed with the incoming … Read more
How Correlation works in WCDMA ? Correlation measures similarity between any two arbitrary signals. Identical and Orthogonal signals: Correlation is used to measure similarity of any two arbitrary signals. It is computed by multiplying the two signals and then summing (integrating) the result over a defined time windows. The two signals of figure (a) are … Read more
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 channel that transfers paging information and system information … Read more