RF Drive Test
Self Learning Tutorial
With Video
Contents
• What is RF Drive Test?
• Why RF Drive Test is Done?
• Tools & Equipment required
• How RF DT is carried out?
• Cases & Analysis
RF Drive Test
• Drive Test is one of the most
comprehensive procedures of testing and
analyzing a Radio Frequency Network
– Coverage evaluation – System availability – Network capacity
– Network retainability – Call quality
RF Drive Test
• Let us understand the meaning of the
terms mentioned in the previous slide
– Coverage Evaluation
– Coverage Evaluation is the process of
measuring the Received Signal Level of the Radio Frequency Signals from a Base Station – The following slides will explain this in detail
RF Drive Test
• Coverage Evaluation: • A cellular mobile
network in a city/town or a rural area is made up of several RF
transmitting and
receiving stations called Base Stations or Base Transcievers.
RF Drive Test
• Coverage Evaluation: • Each cell has its own
transmitting and
receiving equipment that covers a certain geographic area
• As shown each circle represents a cell
RF Drive Test
• Coverage Evaluation: • A group of cells
together form a cluster • The demography of the
cells, for example, the type of terrain –
whether hilly or plain, vegetation or buildings etc., is known as clutter.
RF Drive Test
• Coverage Evaluation: • Clutter data of a cell
and of the geographic area to be covered is very important to
estimate the actual area that will be covered by a Base Station
• The picture on the right shows a sample clutter data – 3D view of an
RF Drive Test
• Coverage Evaluation: • Radio Frequency
signals from a Base Station towards the mobile station and
those from the mobile station towards the
base station suffer due to the clutter.
RF Drive Test
• Coverage Evaluation: • They tend to – Become weaker sometimes – Become stronger sometimes– Get lost due to
absorption or total reflection
• This affects the actual coverage area of a
RF Drive Test
• Coverage Evaluation:
• Let us examine some of the situations occurring due to the clutter
– Deflection is the result of the Radio Frequency wave encountering
obstructions with much larger dimensions than the wavelength of the radio wave. This results in the wave rebounding.
RF Drive Test
• Coverage Evaluation: – Diffraction occurs when
radio waves encounter the edges and corners of obstacles. These act as secondary sources re-radiating beyond what is known as line-of-sight
into the shadow region of the obstacle.
RF Drive Test
• Coverage Evaluation: – Diffusion (Scattering)
occurs when the
dimensions of the object (usually vegetation)
interacting with the radio wave are similar to the impinging wave’s
wavelength. This causes the signal to disperse.
RF Drive Test
• Coverage Evaluation: – Therefore in practical
scenarios, the signal level from a Base
Station at any two
points in the cell even being at the same
distance from the
Antenna, will not be the same due to the clutter variations
RF Drive Test
• Coverage Evaluation: – To understand these
effects, let us first
study in brief, how the Radio Frequency
Signals propagate through Air.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– Primarily there are four
ways of transmission of radio waves
between the
transmitter and the receiver in free space or through Air
RF Drive Test
• Coverage Evaluation: – RF Propagation
– As a Forward or Free
Space Wave
– Earth Wave or Surface
Wave
– Troposphere reflecting
Wave
– Ionosphere Reflecting
RF Drive Test
• Coverage Evaluation: – RF Propagation
– As a Forward or Free
Space Wave
• Free Space Wave moves in straight lines directly between the transmitter and receiver
• Used for Line of Sight Microwave
RF Drive Test
• Coverage Evaluation: – RF Propagation
– As a Ground or
Surface Wave
• Waves reach the
receiver directly and
also after reflecting from earth surface and other obstructions etc.
• This method is used in Cellular Mobile
RF Drive Test
• Coverage Evaluation: – RF Propagation
– As a Troposphere
Reflecting Wave
• Waves reach the
receiver after reflecting from troposphere
• This method is used for waves with wavelengths less than 10 meters
RF Drive Test
• Coverage Evaluation: – RF Propagation
– As a Ionosphere
Reflecting Wave
• Waves reach the
receiver after reflecting from ionosphere.
• It is used for waves having frequencies of more than 300MHz
RF Drive Test
• Coverage Evaluation: – RF Propagation
– Two reasons why
propagation study is important
• It helps in calculating the signal levels within a cell or you can say it
helps predicting the coverage of a cell.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– Two reasons why
propagation study is important
• Secondly, it helps
determining the adjacent channel and co channel interference.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are three
methods of predicting signal level coverage in a cell.
• The First one is based upon pure theory.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are three
methods of predicting signal level coverage in a cell.
• The First one is based upon pure theory.
• It does not take into account the irregularity of the earth’s surface
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are three
methods of predicting signal level coverage in a cell.
• The Second one is based upon
measurements in
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are three
methods of predicting signal level coverage in a cell.
• The Third method is based upon theoretical and actual measurement basis.
• There are various models that are used.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are various
parameters and
phenomena that are required to be studied to understand RF
Propagation.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are various
parameters and
phenomena that are required to be studied to understand RF
Propagation.
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are various
parameters and
phenomena that are required to be studied to understand RF
Propagation.
• Diffraction or Shadowing
RF Drive Test
• Coverage Evaluation: – RF Propagation
– There are various
parameters and
phenomena that are required to be studied to understand RF
Propagation.
• Building & Vehicle Penetration
