4G LTE

How Transport Channel Processing in LTE? Transport channels are block oriented transmission services and transmit one or more transport blocks per transmission time interval (TTI). The TTI is 1 ms (e.g. one sub-frame). Transport blocks may in general have variable size. Typically the number of transport blocks that can be transmitted in a TTI depends … Read more

Physical Channel Types of LTE The physical layer uses resource blocks to transmit binary coded information in QPKS, 16QAM or 64QAM or OOK modulation form. Physical channels determine how data is processed and then mapped via dynamical scheduling onto resource blocks. Thus physical channels also in EUTRAN represent the available physical resources. Like transport channels, … Read more

Transport channels are used as the basic transmission service offered by layer 1 to MAC. MAC will use transport channels to multiplex and demultiplex logical channels onto and from them. In contrast to logical channel types, referring to the type of information transmitted, transport channel types are used to indicate the transport characteristics. This means … Read more

Logical channels are in a one-to-one fashion associated with radio bearers. Logical channel types are used to distinguish the type of information transmitted within the attached radio bearer. The two major groups of logical channel types are therefore control channels for signaling and traffic channels for IP user data. Currently the following logical channel types … Read more

How to Layer 2 Functions and Data Flow in LTE For layer 2 let us first take a look into the uplink. Data transmission is handled through the protocol stack according to the following flow: 1. Data is generated by either signaling control protocols (RRC, NAS) or by some application on the UE’s IP stack. … Read more

Different Tasks and States of RRC Protocol in LTE-EUTRAN The RRC protocol for EUTRAN is responsible for the basic configuration of the radio protocol stack. But one should note, that some radio management functions (scheduling, physical resource assignment for physical channels) are handled by layer 1 and layer 2 autonomously. MAC and layer 1 signaling … Read more

Radio Protocol Architecture in LTE The EUTRAN radio protocol model specifies the protocols terminated between UE and eNB. The protocol stack follows the standard guidelines for radio protocol architectures (ITU-R M1035) and is thus quite similar to the WCDMA protocol stack of UMTS. The protocol stack defines three layers: the physical layer (layer 1), data … Read more

What is SC-FDMA and how it works in LTE? One of the major drawbacks of an OFDMA system is, that the transformation of a complex symbol mapped sequence (e.g. BPSK, QPSK, etc.) onto a small set of subcarriers produces time sequences that have high PAPR (Peak-to-Average Power Ratio). PAPR is the ratio between the maximum … Read more

How Many Different Methods to Combine OFDMA for handle Multiuser System? Threre are four Different Methods to Combine OFDMA for handle Multiuser System. Plain OFDM: Normal LTE OFDM has no built-in multiple-access mechanism. This is suitable for broadcast systems like DVB-T/H which transmit only broadcast and multicast signals and do not really need an uplink … Read more