Indoor LTE with Monte Carlo

Perform indoor network planning with LTE and generate a Monte Carlo report.

Model Type

A multi-story building is described by an indoor database (.idb file) that also contains clutter information with different designations for the various spaces in the building. The building was created with WallMan. The clutter maps are used to define location-dependent traffic upon which cell loads can be determined based on traffic generated during Monte Carlo network simulations. The clutter map in ProMan is as displayed in Figure 1.


Figure 1. Overview of the clutter database.

Sites and Antennas

One antenna site is located on the second floor, and the other is on the fourth floor. Each site has two directional antennas. All the antennas use different carrier frequencies to minimize interference. The frequencies are set to 2115 MHz, 2125 MHz, 2135 MHz, and 2145 MHz.

Air Interface

The air interface is defined by an LTE wireless standard in the file, LTE_Sample_Indoor_MonteCarlo.wst. Orthogonal frequency division multiple access (OFDM/SOFDMA) is the multiple access scheme selected for this air interface. The duplex separation between uplink and downlink is done using frequency division duplex (FDD) and is set to 190 MHz.

Tip: Click Project > Edit Project Parameter and click the Air Interface tab.

Computational Method

As the model is a large office building, a computation method suitable for large structures is required. The dominant path model (DPM) focuses on the most relevant path, which leads to shorter computation times compared to the standard ray tracing model (SRT).

Empirical reflection and transmission coefficients are used for the computation of the received power. Empirical coefficients can be readily obtained through measurements ,but electrical material parameters are more difficult to obtain.
Tip: Click Project > Edit Project Parameter and click the Computation tab to change the model.

Results

Propagation results show at every location, and on every prediction level, the power received from each transmitting antenna. Figure 1 and Figure 2 show the results for the two antennas on the second story.


Figure 2. The power results for Site 2 Antenna 1 on the second story.


Figure 3. The power results for Site 2 Antenna 2 on the second story.
The type of network simulation is a Monte Carlo simulation (location dependent traffic).
Tip: Click Project > Edit Project Parameter and click the Simulation tab to select the Monte Carlo method.
A Monte Carlo simulation offers the possibility to generate distinct users at random locations according to location dependent traffic definitions. A traffic simulation report is generated using the Monte Carlo approach which helps to evaluate the number of users served, blocked and not assigned mobiles (users) for each application and for each cell. The maximum number of snapshots during simulation is 10. The four different states for a mobile user reported in the Monte Carlo simulation are as follows:
  1. Served: The mobile is served by the cell and the corresponding radio resources are allocated for the defined application.
  2. Not assigned: Cell assignment not feasible for the corresponding location (signal level too low and/or SNIR too low), displayed as white pixels in a cell area map.
  3. Blocked (traffic): Cell assignment possible for the corresponding location and Rx power as well as SNIR sufficient for the desired transmission mode, but the required radio resources are not available in the corresponding cell (for example, codes in CDMA and time slots in TDMA).
  4. Blocked (quality): Cell assignment possible for the corresponding location, but for the desired transmission mode the Rx power and/or the SNIR is not sufficient (interference too high).

When a Monte Carlo simulation is performed additional reports for the traffic analysis can be generated by clicking on Monte Carlo Report under Reports in the tree.

A snippet of a Monte Carlo network simulation report is shown in Figure 4:



Figure 4. A section of a Monte Carlo report.
For all modulation and coding schemes used in this model, the network simulation calculates the following:
  • minimum required transmitter power
  • maximum receiver power
  • SNIR
  • reception probability
  • maximum number of parallel streams at a pixel
  • data rate and throughput at a pixel in transmission mode for both downlink and uplink.