Category Archives: Network Planning

Open Signal Coverage Maps for Pakistan

Open Signal is a mobile application that collects the data about your wireless network (2G/3G/4G) and generates coverage maps and host of other reports. The data is collected in the background while the user is busy in his daily routines. But data can also be collected on the request of the user. This is much better than drive testing since the data is collected in real life scenarios and on thousands of different devices that are in use.

The app works while the user is indoor or outdoor, at rest or in motion, on land or on water, at sea level or on a mountain, in dry weather or in rain. Basically anywhere and anytime there are wireless signals available. There are currently 20 million users of the app (both Android and iOS combined) and this number is increasing. In Pakistan all major networks are supported including Jazz, Telenor, Zong and Ufone (both 2G/3G and 4G networks are supported).

JAZZ Islamabad Coverage Map

Telenor Islamabad Coverage Map

Zong Islamabad Coverage Map

Ufone Islamabad Coverage Map

Eclipse

Eclipse 1.0 – A Paradigm Shift in RF Planning

NEW: Simulation of a Moving Transmitter (such as a car)

NEW: Simulation of a Moving Transmitter (such as a pedestrian)

Radio frequency planning is an essential component of network planning, roll-out, up-gradation, expansion etc. Several methods can be adopted for this from something as simple as free space models, empirical path loss models to the significantly more complicated, time consuming and expensive drive testing. Drive testing gives very accurate results but these results can be rendered useless by changing the position of an antenna or the tilt or transmit power of an antenna requiring another run in the field. One solution to this problem is ray-tracing which is very accurate but is usually considered to be very computationally expensive and of little practical value. But recent advances in computational power of machines coupled with efficient techniques have given a new lease of life to this method.

Eclipse is a near real-time simulation software for prediction of signal strength in urban areas. The software uses shooting and bouncing ray (SBR) method of ray tracing with 1 degree ray separation, 1 m step size and 9 interactions per ray path. The simulation parameters can be varied according to the resolution required. The code is highly optimized to give results in shortest possible time. It is especially useful for network planning of ultra-dense wireless networks where a dense network of antennas is placed on lamp posts instead of telecom towers. Various frequency bands can be simulated, along with different antenna radiation patterns and MIMO configurations.


Helsinki 3D Building Data

 

Path Followed by a Single Ray

 

Paths Followed by Multiple Rays

 

Received Signal Strength Over Area of Interest

Note: If you would like to run a test simulation send us a request at info@raymaps.com

Antenna Radiation Pattern and Antenna Tilt

An introductory text in Communication Theory would tell you that antennas radiate uniformly in all directions and the power received at a given distance ‘d’ is proportional to 1/(d)^2. Such an antenna is called an isotropic radiator. However, real world antennas are not isotropic radiators. They transmit energy in only those directions where it is needed. The Gain of a antenna is defined as the ratio of the power transmitted (or received) in a given direction to the power transmitted in that direction by an isotropic source and is expressed in dBi.

Although antenna Gain is a three dimensional quantity, the Gain is usually given along horizontal and vertical planes passing through the center of the antenna. The Horizontal and Vertical Gain patterns for a popular base station antenna Kathrein 742215 are shown in the figure below.

Kathrein 742215 Gain Pattern
Kathrein 742215 Gain Pattern

The actual Gain is given with respect to the maximum Gain which is a function of the frequency e.g. in the 1710-1880 MHz band the maximum Gain has a value of 17.7dBi. Another important parameter is the Half Power Beam Width (HPBW) which has values of 68 degree and 7.1 degree in the horizontal and vertical planes respectively. HPBW is defined as the angle in degrees within which the power level is equal to or above the -3 dB level of the maximum.

Also shown in the above figure are approximate Horizontal Gain patterns for two antennas that have been rotated at 120 degrees and 240 degrees. Together these three antennas cover the region defined as a cell. There would obviously be lesser coverage in areas around the intersection of two beams.

A somewhat more interesting pattern is in the vertical direction where the HPBW is only 7.1 degrees. Thus it is very important to direct this beam in the right direction. A perfectly horizontal beam would result in a large cell radius but may also result in weak signal areas around the base station. A solution to this problem is to give a small tilt to the antenna in the downward direction, usually 5-10 degrees. This would reduce the cell radius but allow for a more uniform distribution of energy within the cell. In reality the signal from the main beam and side lobes (one significant side lobe around -15 dB) would bounce off the ground and buildings around the cell site and spread the signal around the cell.

Antenna Tilt of 10 Degrees
Antenna Tilt of 10 Degrees

The above figure gives a 2D view of signal propagation from an elevated antenna with a downward tilt of 10 degrees in an urban environment.