As we know, every cell has several TRX and every TRX includes 8 timeslots (i.e. providing 8 basic physical channels). In the radio subsystem, the physical channel supports the logical channel based on the type of message transmitted . In this way, the physical channels are mapped as different logical channels. In the GSM system, … Read more
Actually, during the communication process, the mobile subscriber talks only 40% of the time and there is not much useful information transmitted during rest of the time. If all the information is transmitted to the network, it will not only be a waste of the system resources but also add more interference to the system. … Read more
Correlation Is a Measure of How Well a Given Signal Matches a Desired Code, The Desired Code is Compared to the Given Signal at Various Test times. Correlation is key enabling concept for direct sequence CDMA systems. Correlation is a measure of how well a given signal spread with a digital code matches a desired … Read more
Frequency diversity is inherent in a spread spectrum system. A fade of the entire signal is less likely than with narrow band systems. Combats Fading, Caused by Multipath Fading Acts like Notch Filter to a Wide Spectrum Signal May Notch only Part of Signal Fading is caused by reflected images of an RF signal arriving … 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
The UE carried out a restriction of access check during connection establishment. This function provides a means of controlling traffic load from the EU. There are separate facilities for control of Mobile originated (MO) calls and signaling. On top of regular class, parental control, specific Access Control Services (SSAC) can be applied. SSAC facilitates separate … Read more
As previously I write about fading effect in GSM here I write about Fade Margin Calculation in GSM. Cell area probability (CAP ) is the percentage of the cell area that has signal strength greater than the receiver sensitivity. CAP is dependent on the radio environment, primarily the standard deviation of the log normal faded … Read more
Site selection is based on a number of criteria. It may not be possible to satisfy all these criteria at the same time, but it is important to select the best sites available. Drive test sites should be selected to give a good representative sample of the system coverage area. The exact number of sites … Read more
Here I write on LTE TDD Specific Frequency Planning Considerations. What to consider and why for TDD Frequency Planning. It is very common for telecom Operators within the TDD band of LTE have a wider unpaired spectrum than the bandwidth defined maximum carrier bandwidth of 20MHz. As a result, the selection of carrier bandwidth for … Read more
When we talk about antenna then we need to understand about antenna installation and specially about antenna downtilting.lets assume that antenna installed then how you can change its position. Its two type, left-right = its called azimuth change. up-down = its called tilt change. Lets understand from start. ANTENNA INSTALLATION Antenna installation configurations depend on … Read more