Basically Diversity Antenna required because of Signal Rich at mobile or BTS by reflection and this change value of its level and quality either good or bed. Let’s understand in detail. NEED OF DIVERSITY In a typical cellular radio environment, the communication between the cell site and mobile is not by a direct radio path … 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
In mobile communications two main categories of antennas used are Omni and Directional antenna here I write about antenna characteristics and use. ANTENNA TYPES Omni directional antenna These antennas are mostly used in rural areas. In all horizontal direction these antennas radiate with equal power. In the vertical plane these antennas radiate uniformly across all … Read more
Drive test is simply test of coverage for radiating BTS . from drive test you can imagine BTS coverage boundary and foot print of bad coverage and good coverage.lets understand dt basic. Drive Test Plan Each drive route should be marked on a detailed road map showing the exact route to be driven. These maps … 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
Cable test is first understanding for any RF Engineer here i write how to test cable integrity and Cable loss and testing of Transmitter in gsm. Cable Integrity Test Cable integrity is checked by measuring VSWR. A good known cable is connected from the test transmitter to the wattmeter. The cable under test is placed … Read more
INTRODUCTION Predesign drive test for measurement integration This is at beginning of design when no site has been built or even selected. All test sites are temporary. Drive test is performed mostly for characterization of propagation and fading effects in the channel. The object is to collect field data to optimize and adjust the … Read more
Hata Model is applied for GSM Link Budget,here i write about its formula and Cell Size Estimation. Hata´S Empirical Formula PL = 69.55 +26.6log10fc – 13.82log10hb + (44.9 – 6.55log10hb)log10R – a(hm) -CF Where , fc – Frequency in MHZ hb – Transmitter antenna height hm – Receiver antenna height R – Radius in Km … Read more
Receiver sensitivity is the ability of the receiver to receive signals in the sense that any signal below the sensitivity is considered as noise and is not usable. Receiver sensitivity is given by S = Antenna Noise (dBm) + Receiver Noise Figure (dB) + C/N (dB) S = the receivers sensitivity C/N = Carrier to … 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