9.6 Tools for Indoor Predictions
It is true that once you have done 20 or 30 indoor design, radio surveys and post installation measurements, you will have a really good feeling, and even a sixth ‘RF sense’. It is important to recognize and trust that feeling and experience, but always do a link budget, and do use a link calculation, at least in the expected worst case areas of the building.
If you only use your experience, you might make expensive mistakes, or expensive overdesigns of the DAS solutions. If you want to utilize your experience, the best way is to first plot the antennas on the floor plan, then re-check with link budget and propagation simulations, maybe even RF survey measurement with a test transmitter in the building, to confirm you are right. This will make your ‘gut feeling’ even better.
9.6.1 Spreadsheets Can Do Most of the Job
Like the link budget calculator, you can use a standard Excel spreadsheet to predict the coverage in the building. This approach is limited to calculating a specific level or distance in a specific area or place in the building. Therefore you will simulate the worst case in the building, and also several location samples that represent the building.
9.6.2 The More Advanced RF Prediction Models
Some tools are able to import floor plans and to define the loss of the individual wall and floor separations. The most advanced of these prediction tools can even calculate ‘ray-tracing’, estimating the signals being reflected throughout the building ...