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…
Types of Handover in LTE
The Handover is the process of transferring an ongoing call or data session fromone cell connected to the core network to another It is transparent for the end user It…
Which Cell Parameters needs to Obtain in LTE?
To provide the most critical information to the UEs, the eNodeB uses the BCH channel The information is sent on pre-defined time-frequency resources. This information is organized into different information…
CDMA Protocol Stacks
The original release of the EIA/TIA-95-B standard defined the protocol messages and formats to be used in the CDMA system. This release is know as Revision 0 of the IS-95…
Modulation in LTE
The 3G LTE uses 3 Quadrature Amplitude Modulations (QAMs) depending on the radio quality. QAM uses both the amplitude and the phase. LTE devices use QPSK, 16QAM and 64QAM to…
Radio Wave Spectrum
The radio waves are distributed in 3Hz ~ 3000GHz. This spectrum is divided into 12 bands, as shown in the above table. The frequencies in each specific band present unique…
What is Interleaving
If the voice signal is modulated and transmitted directly after channel coding, due to the condition changes in mobile communication channel, a deep of the fading will influence a…
How SIM works in GSM
The SIM card contains its internal memory, in which the data, personal and financial information as well as the identity for GSM / CDMA are stored. The SIM card stores…
Ranging in Wimax
The initial range is the process of estimating the distance or propagation time between a transmitter and a receiver. Area information can be used to assist in setting operating parameters…
Signal Fading
A transmitted signal changes as it travels to the receiver. The effect of these changes is commonly referred to as fading. The fading results from the superimposition of transmitted signals,…