Air does not brake

By Mika Skarp

Quite often, I hear the statement that in mobile networks there’s nothing that can be guaranteed. Where is this sentiment coming from, why we can’t trust radio networks? For sure, the fact that we can’t see radio waves, like we can see and touch cable, is a factor. Radio waves elicit an idea of some kind of magic and uncertainty.

However, aerial TV signals have been delivered reliably for decades. In the same manner, microwave links have been used for years to connect base stations and nodes in telecom networks. From the perspective of the signal, it really does not matter if it is delivered through air or cable.

Original consumer data networks were based on a philosophy of best practice. Therefore, it was easy to manufacture compatible equipment for different vendors. Quite soon, technologies to provide Quality of Service features were established, but used only in fixed networks. In mobile networks, on the other hand, QoS caused challenges as access control was not considered a QoS feature and cell breathing was considered a problem.

In order to be able to guarantee connections in commercial networks, you need to understand scheduling parameters. Besides, a number of simultaneous users and bearers need to be taken into account. But what about cell breathing? In mobile networks, you need to also understand the needed RF power level to deliver the requested service.

We can calculate the device throughput when we have a high enough RF level related to the service needed. Next, we need to know the maximum number of simultaneous resource users and scheduling parameters. The point here is that different applications require different amounts of capacity to work properly. Therefore, changing scheduling parameters dynamically is a useful technique and can actually guarantee capacity when RF levels are at their required height.