TETRA Coverage, Urban

Perform TETRA network planning in an urban scenario.

Model Type

This is an example of a TETRA network planning project in an urban scenario. The geometry is described by topography and urban buildings, see Figure 1.
Figure 1. Urban database: topography and buildings.


Sites and Antennas

Three transmitter sites are defined in the urban area as follows:
  • Site 1 with three directional antennas at a height of 25 m
  • Site 2 with three directional antennas at a height of 22 m
  • Site 3 with two directional antennas at a height of 25 m
Each antenna operates on a unique carrier frequency near 395 MHz.
Tip: Click Project > Edit Project Parameter and click the Sites tab to view the sites, antenna patterns, and carrier frequencies.

Air Interface

The air interface is defined by a TETRA wireless standard (.wst) file. TETRA uses time division multiple access (TDMA) with four time slots per radio carrier and 25 kHz spacing between carriers. Frequency division duplex (FDD) separation between uplink and downlink is set to 10 MHz.

Tip: Click Project > Edit Project Parameter and click the Air Interface tab to view the carriers and transmission modes.

Computational Method

The dominant path model (DPM) computation method is selected. This method focuses on the most relevant path, which leads to a shorter computation time compared to full ray tracing, while still providing high accuracy.

Tip: Click Project > Edit Project Parameter and click the Computation tab to change the model.

Results

Propagation results show at every location the power received from each transmitting antenna. Results are calculated for a single prediction plane at 1.5 m height. Simulation is performed for each individual transmitter. Therefore the prediction (simulation) area is the superposition of the prediction areas defined individually for each transmitter.

For all modulation and coding schemes used in this model, the network simulation calculates minimum transmitted power, maximum received power, SNIR (max), and reception probability for both uplink and downlink.

Figure 2 shows the data rates for network planning. By TETRA standards, high data rates can be expected almost everywhere. The fact that each base station antenna has its carrier frequency minimizes interference.

Figure 2. Maximum data rates for the network planning.