Inter-cell interference coordination (ICIC) in LTE To aid downlink ICIC Relative narrowband transmission-power indicator A cell can provide this information to neighboring cells, indicating the part of the bandwidth where it intends to limit the transmission power. A cell receiving the indication can schedule its downlink transmissions within this band, reducing the output power or … Read more
After the power on, the UE knows: the UE category and capability. the preferred PLMN. the carriers. The UE needs to know: The frame synchronization to be able to decode the DL radio frame. The cell parameters to be able request a connection. The UE can use: The PSS: Primary Synchronization Signal. The SSS: Secondary … Read more
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 the radio quality, the TB is coded and interleaved. … Read more
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 part of the MAC layer and controls the assignment of uplink and downlink resources. Multiplexing/Demultiplexing … 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
Cell Edge Rate in LTE is simple if it’s High then Coverage Low and if It’s Low then Coverage high similar to Frequency selection. Not clear lets understand in detail. Cell Edge Rate in LTE Similar to other wireless communications systems, such as CDMA2000 EVDO, WiMAX and HSPA, the LTE features a rate layering feature. … 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
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 feedback channel (although such systems exist too). Packet Statistical Multiplexing: It … Read more
Based on DCI formats In LTE Three types of allocation are used: type 0: DCI formats 1, 2, 2A type 1: DCI formats 1, 2, 2A type 2: DCI formats1A, 1B, 1C, 1D One bit in the header is indicating if DCI formats 1, 2, 2A are of type 0 or type 1. Type 0: … Read more
OFDM Fundamental OFDM was selected for the downlink because it can Improved spectral efficiency Reduce ISI effect by multipath Provide better Protection against frequency selective fading OFDM is a scheme that offers good resistance to multipath and is now widely recognized as the method of choice for mitigating multipath for broadband wireless. It can be … Read more