Tell us a little about yourself. What does your job at Telefónica involve?
I started at Telefónica in the e-Health department, where I was involved in the implementation and development of projects that brought technology to chronically ill patients and in monitoring opportunities for cardio-protection columns. I have always been fascinated by bringing the worlds of technology and health together. Knowing that your work helps others in such important areas as health is really rewarding.
Some time later, I continued my adventure in LAN/WiFi Network Specialist Engineering, specialising mainly in WiFi projects, carrying out both theoretical and on-site coverage studies, as well as designing the associated WiFi network, collaborating and providing support to other areas, and negotiating the best technical and economic conditions with various external suppliers. I learned a lot during this time.
My journey continues today, as I wanted to keep exploring and learning, so I landed in operations, in Radio Optimisation Management, specifically in Mobile Access Quality Analysis, and… it’s been amazing too.
What is your specific role within the company?
As I mentioned earlier, I am currently in the Mobile Access Quality Analysis department, collaborating with the Ericsson team and working on the Low Triple Band Site Analysis project.
This project consists of analysing the different sites that already have triple low bands (L800, LU900, LN700) and detecting whether they are suffering from PIM (passive intermodulation) in order to try to eradicate the problems caused by it (just in case, don’t panic, I’ll give you a brief overview below so you can see how interesting it is).
Passive intermodulation (PIM) is a non-linear response of two or more signals of different frequencies when elements with non-linear effects are found in the RF path.
If these new signals have a frequency that falls within an operator’s service band, the noise level increases, causing a decrease in data bit rates, a deterioration in signal quality, an increase in dropped call rates and reduced network capacity. The impact of PIM can therefore be very severe on network performance, especially in systems such as UMTS or LTE.
What does ‘service guarantee’ mean in the context of a network such as Telefónica’s?
Service guarantee is the commitment to provide adequate levels of quality to the network. From a mobile access perspective, quality is key in an environment such as Telefónica’s, where we have thousands of sites with base stations operating with different technologies.
We have to provide our customers with a high-capacity connection for voice and data transmission that is, of course, stable and reliable.
To do this, we use a set of technologies to ensure that different types of traffic get the right availability, priority and performance.
Mobile access quality analysis evaluates the performance of mobile networks from the perspective of the end user, who should have a good experience when connecting and using mobile services.
What parameters are used to measure network quality?
Various indicators (KPIs) are used to measure quality. I will briefly mention some of them:
- Accessibility: to see if the user can connect to the required service.
- Availability: measures service continuity.
- Signal strength: various indicators (RSSI, RSRP, RSRQ, SINR) related to signal strength, interference level and noise.
- Delay (latency): network response speed.
- Drop rate: interrupted calls or data sessions.
- Failed attempt rate: connections that are not completed.
- DL/UP throughput: download/upload speed.
How do you ensure that customers have a continuous and uninterrupted service experience?
Mobile Access Quality Analysis monitors network quality by focusing on these four pillars:
- Call diversion: together with other areas, the KPIs to be reviewed and their thresholds are agreed upon, so that each technology and band will have its own KPIs to be monitored. If these KPIs are outside the established thresholds, the deviation is diagnosed and the appropriate actions are taken to resolve the problem (including escalating it to the relevant department if necessary).
- Interference management: external interference can significantly degrade network capabilities. Each case is analysed to determine whether it is actually external interference or PIM. In the event of external interference, a series of information will be collected (affected cells, whether or not there are neighbouring cells in the same situation, map with location, affected bands, signal strength, existence of repeaters nearby, pattern, etc.) which will be forwarded to the appropriate resources for location and neutralisation. If it is PIM, remote tests will be carried out and the relevant information will also be forwarded to the designated personnel so that further tests can be carried out on site in order to locate the element causing the PIM and subsequently take the appropriate action to resolve the problem.
- Complaint handling: after analysis by the relevant unit, complaints caused by problems in the mobile access network will be analysed and the appropriate measures will be taken to resolve them.
- Power-up validation: when a new system is to be implemented or a modification is to be made to an existing system, it is ensured that the quality of the existing network is maintained and that minimum quality standards are met for the new system. To this end, configuration checks are carried out, the system is checked for alarms, fibre/coaxial connections are checked to ensure they are correct, the inclination of the different antennas is checked to ensure it is correct, the power levels are checked to ensure they are correct according to the technology in question, etc. On the other hand, different KPIs are analysed in order to see the impact of the new system on the existing network, also checking that the RSSI is correct and that it is free of PIM. If it does not comply with what has been agreed, the start-up will not be validated and it will be necessary to rectify all the faults in order to revalidate it.
WiFi or 5G?
One might think that with the arrival of 5G, WiFi could disappear. The reality is that both types of networks can complement each other and, depending on the use case, one or the other may be more recommendable. While it is true that there are some notable differences between the two:
Coverage: with WiFi up to tens of metres per AP, however, with 5G up to kilometres per cell.
Speed (theoretical): with WiFi 6E/7, speeds are lower than with 5G using millimetre waves (mmWave).
Latency: with WiFi 5-30 ms, with 5G 1-10 ms (URLLC).
Mobility: with WiFi limited to a certain number of APs on the network, with 5G high mobility (handover).
Concurrency: with WiFi approx. up to 100 simultaneous users per AP, with 5G thousands of devices per cell.
Deployment: WiFi involves lower costs and easier installation, while 5G is more complex and expensive, requiring infrastructure, licences and operators.
Quality of service: can be applied with WiFi, but is more limited than with 5G.
Some use cases:
- WiFi: home use, educational use, office.
- 5G: industrial IoT environment, ultra-reliable and low-latency network (URLLC), gaming, vehicle transport.
- WiFi or 5G, even complemented: stadiums, HD video needs, streaming.
