Dear Andre,

The tilt angle of the base station antenna in important for determining the coverage area and the cell and the interference to the adjacent cells.

The study in the given link for optimum tilt angle for 3G may be useful to determine the optimum tilt angle for the 5G: https://pdfs.semanticscholar.org/8c63/8f3edb1dcf63c01b66d13b5166565d743ef9.pdf

Best wishes

Hi André,

I don't think there is a single answer for this question, since it depends on the objective you have.

For the load balancing purposes, for instance, you would get some optimum value, which also depends on the loads of the main and adjacent cells. For maximum coverage, on the other hand, you might get very different optimum.

It would be a good practice to define the problem first and write down the mathematical model in order to have an optimization objective.

Regards

Hi.,

The tilt represents the inclination or angle of the antenna to its axis.

If the height refers to the height of a ground-mounted monopole, it would depend on the type (1/4 wave, 1/2 wave, 5/8 wave, etc.) For a frequency in MHz (which is suggested by 107.7), use the formula of λ=300/f. Modify the number by the type of antenna

Dipole Antenna Length. When determining how long to make each leg of a Dipole antenna, dividing the frequency in MHz into 468 will give the overall length. To find the half wave, divide that number by two. This will give you the length of each leg of the antenna.

Kindly Check:

https://community.cambiumnetworks.com/t5/LINKPlanner/How-to-calculate-the-correct-tilt-for-an-AP/td-p/70816

Metin Ozturk I have defined an inter-site distance and now I intend to achieve maximum coverage

Then, basically, you might want to extend the coverage at the expense of QoS degradation. In my opinion there are multiple options in this case.

For example, you can have a threshold value for the user received SINR value, say -3dB, and then you can extend the coverage by tweaking the antenna tilt until all the users receives at least the threshold SINR. Therefore, in this way, you maximise your coverage with a guarantee of everyone is kind of covered.

Nonetheless, although you are guaranteeing the coverage for everyone (no link failure), you are still compromising on the the throughput.

Thus, you might need to find out how much throughput degradation you can tolerate. For the eMBB scenario in 5G NR, for example, the required peak data rates are quite high, so the degree of freedom is limited.

Yo might want to write an optimisation problem including the throughput and the antenna tilt so that the problem may be solved analytically. Otherwise, you can always go for heuristics or machine learning algorithms, such as reinforcement learning, in order to find a good policy for this. But, keep in mind that the heuristics and reinforcement learning do not always guarantee the optimal.

On the other hand, if you are talking about MIMO, things are a bit different, since there is a beamforming concept. The structure/parameters of the optimisation problem could be different, you should check this.

In short, the scenario, objective, and constraints play an important role for this task.

Regards

Metin Ozturk firstly, thank you for your time and patience! I am in fact working on mMIMO and beamforming by developing an antenna model with up to several narrow beams. I was thinking of using the Wu & Yuan (1996) expression ( downtilt=arctan(h/d) + 3dB_beamwidth/2 ) for the downtilt of my central beam.

André Alves this is the classical equation for antenna down-tilt calculation, which can be easily derived using fundamental trigonometry. In other words, this is the final formula you should use after your optimisation.

I am focusing on optimisation part, since you mentioned 'optimal antenna tilt' in your question. However, if you are just looking for developing your simulations; such that 'd' is taken as the distance between the base station and the cell border (half of the inter-site distance). Then, this equation is employed to calculate the antenna tilt. To sum up, if you are just looking for setting up your simulations rather than optimising the antenna tilt, then you can go ahead with this equation and you will be fine.

On the other hand, if you are looking for somehow optimisation for any objective, then, as I said earlier, the problem formulation is integral part of your work. In this case, 'd' and even 'h' parameters in the equation would be part of the optimisation process. Besides, there are many things to consider, such as interference and coverage gaps; the higher values of antenna down-tilt would result in coverage gaps, whereas the interference becomes more effective for smaller values of the down-tilt due to the fact that increased footprint for each base station makes the overlapping coverage areas more likely.

Regards