How is Basic Frame Structure in LTE ?

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 of 1 ms. Each sub-frame is made … Read more

OFDMA Parameter for LTE

OFDMA Parameter for LTE How Many OFDMA Parameter for LTE? Which is OFDMA Parameter for LTE ? The width of a Sub-carrier is 15 kHz whatever the bandwidth The bandwidths are: 1.4, 3, 5, 10, 15 and 20 MHz Note that in LA1.1, only 5, 10 MHz are implemented The symbol duration is always the … Read more

SC-FDMA Receiver Benefits in LTE

Benefits of SC-FDMA Receiver in LTE Low Peak-to-Average Power Ratio (PAPR): SC-FDMA (Single-Carrier Frequency Division Multiple Access) exhibits a lower PAPR compared to other modulation schemes, reducing the demand for power amplifiers with high linearity. Improved Power Efficiency: Lower PAPR contributes to improved power efficiency, making SC-FDMA well-suited for mobile devices with limited battery capacity. … Read more

Difference between DL and UL in LTE

What is main Difference between DL and UL in LTE ? OFDMA Advantages Robust against narrow-band co-channel interference Robust against Intersymbol interference (ISI) and fading High spectral efficiency Efficient implementation using FFT Drawbacks High Peak-to-Average Power Ratio The power limitation is more problematic in UL than in DL Signal with high PAPR will limit the … Read more

OFDMA Transmitter in LTE

How OFDMA Transmitter in LTE ? In the downlink, OFDM is selected to efficiently meet E-UTRA performance requirements. With OFDM,  it is straightforward to exploit frequency selectivity of the multi-path channel with lowcomplexity receivers.  This allows frequency selective in addition to frequency diverse scheduling and one cell reuse of  available bandwidth. Furthermore, due to its frequency domain … Read more

Cyclic Prefix problem in LTE

Cyclic Prefix problem in LTE The cyclic prefix (CP) in LTE is a guard interval inserted in the time domain between successive symbols or OFDM (Orthogonal Frequency Division Multiplexing) symbols. Its purpose is to mitigate the effects of multipath fading and inter-symbol interference by providing a guard time that allows the signals to settle before … Read more

Inter-Symbol Interference in LTE

Inter-Symbol Interference in LTE Definition: ISI is a phenomenon in LTE where symbols transmitted over a communication channel overlap, causing distortion in the received signal. Causes: Multipath Propagation: Signals take multiple paths with different delays, leading to overlapping symbols. Time Dispersion: Variation in signal arrival times at the receiver contributes to ISI. Impact on LTE: … Read more

LTE Sub-carrier

LTE Sub-carrier How Many Sub Carrier in LTE? Read below,..There are different kinds of sub-carriers: Data sub-carrier Pilot Sub-carrier DC sub-carrier Guard Sub-carrier The result is intersymbol interference not only within a subcarrier but also between subcarriers. To prevent symbols from overlapping and to reduce the intersymbol. DC stands for Direct Current and it is … Read more

Notion of Orthogonality in LTE

In FDM, the sub-carriers are separated in the frequency domain to avoid interference between the sub-channels It results in a loss of spectrum efficiency because the frequency guard band can not be used to send data.The OFDM allows one to remove the frequency guard band.   Benefit: There are more sub-carriers, so more symbols are … Read more

OFDMA Principles in LTE

OFDMA Principles in LTE Orthogonal Frequency Division Multiple Access (OFDMA) is a key technology used in Long-Term Evolution (LTE) to efficiently manage the transmission of data over the radio interface. Here’s an explanation of OFDMA principles in LTE: Frequency Division Multiplexing (FDM): OFDMA uses FDM to divide the available frequency spectrum into multiple subcarriers. Each … Read more