Comparing mobile radio networks performance is an increasingly actual and interesting topic; Italian mobile companies compete with each other with features and technological innovations, supported by their respective radio and core network vendors, to give high-level customer experience on all main services, even in mobility.
From the first appearance of 4G, up to 4G+ and now to the beginning of 5G, still not completely standalone, the competition between companies it’s based on downlink and uplink speed tests and voice quality; performances on the most widespread OTT applications are compared, and the main technological innovations are competed to graft onto the networks.
We are lucky to be among the technical partners of this competition, and this pushes our team to constant detailed studies and trainings, to always take an extra step to be prepared to support the testing phases that our customers ask for.
We work throughout the country and, thanks to advanced instrumentation such as Rohde & Schwarz, and to Business Intelligence analysis tools (e.g. Tableau), we have recently carried out some interesting tests in the motorway sector for a benchmark analysis of tunnels coverage on GSM and LTE technologies.
Tests was carried out in both travel directions, where present, and with particular attention also to the stretches of road (500 m) prior to tunnel entrance.
Regarding LTE technology, the reference kpi is the NB-RSRP (Narrow Band- Reference Signal Received Power), detected through the use of a special LTE Scanner on the PBCH (Physical Broadcast Channel), described in the following image.
PBCH transmits essential parameters for initial cell access, such as the bandwidth of the downlink system, the Physical Hybrid ARQ Indicator Channel (PHICH) structure and the eight most significant bits of the System Frame Number.
The use of this type of Narrow Band measurements, on a limited number of sub-carriers compared to the similar Wide Band (1 MHz Vs 3 MHz), allows to obtain a result that is independent of the traffic load of the cell in question, and to borrow the behavior of a normal UE synchronized on the Primary cell.
The measurements were carried out on the various LTE layers, identifying for each individual tunnel, the signal trend both on the primary cell and on the others, as shown in the following image.
The post analysis carried out with the tool Tableau revealed the presence or absence of the various LTE layers (800/1800/2100/2600), and identify the most critical situations together with those in which there was the presence of repetition equipments or dedicated coverage systems.