System information 1920 bits or 1728 bits are to be transmitted for normal or extended CP resp.. The PBCH is transmitted every 40 ms. The bit scrambling depends on the cell id and is starting in radio frames 0, 4, 8 … . PBCH uses QPSK. I.e. 960 (864) symbols need to be allocated. Mapping … Read more
Less complex modulation. OFDM is a simpler modulation technique that is better suited to deployments that do not require support for mobility. License-exempt bands. Mobile services require licensed spectrum to provide coverage in wide areas. Fixed deployments, however, have often successfully used license-exempt bands in areas where interference levels are acceptable. For this reason, most … Read more
In 1998, the Institute of Electrical and Electronics Engineers (IEEE) formed a group called 802.16 to develop a standard for what was called a wireless metropolitan area network, or wireless MAN. Originally, this group focused on developing solutions in the 10GHz to 66GHz band, with the primary application being delivering high-speed connections to businesses that … Read more
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 same whatever the bandwidth … Read more
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
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 … Read more
Adopting a multicarrier approach for multiple access in LTE was the first major design choice. The choice of multiple-access schemes was made in December 2005, with OFDMA being selected for the downlink, and SC-FDMA for the uplink. Both of these schemes open up the frequency domain as a new dimension of flexibility in the system, … Read more
SC-FDMA utilizes single carrier modulation, DFT-spread orthogonal frequency multiplexing, and frequency domain equalization. LTE uses OFDMA on the DL. It allocates DL bandwidth to the user based on resource blocks, rather than individual subcarriers. When the signal is a combination of subcarriers, high amplitude power peaks can occur. The base stations power amplifiers are designed … Read more
LTE OFDMA and Downlink Frame Structure Details Downlink OFDMA time-frequency multiplexing LTE Spectrum Flexibility and Bandwidth FDD downlink frame structure detailed TDD frame structure LTE (any OFDM/OFDMA) band is made up of multiple small spaced channels and we call each of these small channels as “Sub Carrier”. Space between the chhanel and the next channel … Read more
The control plane includes the application protocol. It also includes the signaling bearers for transporting the application protocol messages. The application protocol is used for setting up bearers in the radio network layer. For example, radio access bearers or radio links. Figure shows “Control plane protocol stack” comprises Radio Resource Control (RRC), Packet Data Convergence … Read more