What is HLR and VLR and its function in GSM
As From the Name VLR means Visitor Location Register and HLR means Home Location Register so HLR having all detail of subscriber and VLR having temporary details for mainly call…
What is Cyclic prefix in LTE ?
The guard period after each rectangular pulse carrying the modulated data symbol is a simple and efficient method to deal with multi-path reception. The cyclic prefix (CP) simply consists of…
OFDM Receiver and How it work for LTE?
The receiver is like in any other radio system the more complicated part. In radio systems and of course also OFDM there are two special points a receiver has to…
OFDM implementation in Detail
A typical OFDM transmitter is shown on the following figure. To reduce the amount of RF hardware required for OFDM the modulation process is split into two parts. A first…
Difference Between OFDM and FDM in LTE
FDM in LTE Conventional multi-carrier operation as it is used for FDM works simply by selecting a number of center frequencies – one for each carrier to be used. The…
Inter-Carrier Interference for OFDM
The price for the optimum subcarrier spacing is the sensitivity of OFDM to frequency errors. If the receiver’s frequency is some fractions of the subcarrier spacing (subcarrier bandwidth) then we…
Pulse shaping and spectrum in LTE
RF engineering is a trade off between: required radio spectrum (bandwidth), speed of data transmission (bit rates) and complexity of implementation. The pulse form used to modulate complex data symbols…
How to LTE Radio Air Interface?
The state-of-the-art design of the LTE air interface is characterised by OFDMA (DL) and SC-FDMA (UL) together with MIMO. The downlink modulation is based on OFDMA (Orthogonal Frequency Division Multiple…
How Many CODES in CDMA?
There Are Three Codes in CDMA PN Long Code,PN Short Code & Walsh Code. PN Long Code The Long Code is a PN sequence that is 242 – 1 bits…
How Frame Structure in Wimax ?
The physical frame includes the downlink sub-frame, uplink sub-frame, TTG, and RTG. The physical frame length and the respective duration of downlink sub-frame and uplink sub-frame are broadcast by the…
Which Types of Antennas Used in WIMAX ?
WiMAX antennas, just like the antennas for car radio, cell phone, FM radio, or TV, are designed to optimize performance for a given application. The figure above illustrates the three…
How Modulation-QPSK in CDMA ?
In an actual application, the system implements the modulation in this way: as shown above, I and Q channel sequences in the figure represent two channels of cyclic PN…