One of Portugal’s deadliest forest fires broke out on Saturday 17th June 2017 in the central municipality of Pedrógão Grande before spreading to neighboring areas including Góis, Pampilhosa da Serra and Arganil. It was finally brought under control on 22nd June but with a tragic loss of life and injuries.
When commercial and TETRA wireless networks went down in the affected areas, it cut off village residents and hampered efforts of the fire and rescue services. Based in Portugal, Cliff Velosa on behalf of Comba Telecom, took part in setting up temporary communication networks in the affected area to reconnect residents and emergency services. Cliff recounted the exercise and how Comba Telecom, its partner Drivetel and one of the local mobile network operators (MNO) worked together for an immediate solution.
Q: When did you first become aware of the situation and the need for action?
Cliff: The local operator called me up on Sunday morning and told me that the wireless networks were down at the disaster-stricken zone. The base stations serving the area were inoperable since the fiber optic backhaul had been destroyed by the flames. Nearby villages were essentially cut off and had no means to communicate with the outside world and we needed to restore mobile connectivity ASAP. Adding to the urgency was the fact that the public safety TETRA network had also fallen at the time which hampered the fire and rescue teams. In any case, the sensitivity of the situation was clear and we had to act very quickly.
I immediately contacted our partner Drivetel and together with the local MNO, we prioritized the requirements and came up with a solution that restored connectivity in a matter of hours.
Q: What was the solution?
Cliff: Working with MNO , we ascertained the priorities - restoring voice communications, , and above all, rapid deployment time. Together we analyzed the situation and decided that a portable repeater station was the best solution to restore communications.
Q: Why a portable repeater station and not a portable base station?
Cliff: Remember, the mobile backhaul lines had all been destroyed by the fire - so without the backhaul, a portable base station would be useless. We could have deployed a series of microwave links, but the extra time taken to set up and configure would have been critical, especially when lives are at stake.
Q: Please continue to elaborate on the solution and deployment.
Cliff: Comba Telecom has worked with Drivetel for many years in delivering solutions to our customers and we have a very strong partnership. Previously, we had worked together to create a coverage solution for situations such as events which only needed temporary coverage and therefore had equipment such as Comba’s repeater, donor and panel antennas already in stock. As such we could quickly pull together a fully integrated portable repeater on-site. Comba Telecom Channel Selective Repeater is at the system core because we knew the closest base station where the signal would be “borrowed” was quite far and its 100dB gain would compensate for loss and the 40dBm output power would amplify the signals.
In such critical situations, we needed a quick solution to deploy and get the wireless network back online. All in all, it was a matter of (intense) hours between receiving the call and finally activating the solution.
Q: What were the challenges and why?
Cliff: Not so much of a challenge, but more of time consumed: setting up the system was relatively fast – it was the logistics of transporting the repeater station from Lisbon to rural areas and coordinating with the RF Planning team that took some time. However, I am proud to say that we eventually prevailed given this was an unexpected situation.
From a technical standpoint, we had to work carefully to configure the system to address and overcome isolation issues between the donor and service antenna. Fortunately, the Comba Digital repeater features ICE (interference cancellation equipment) capabilities which minimizes the interference between serving antenna and pick up antenna – very important in such scenarios with limited isolation. Additionally, we needed to do careful cell planning and align channels in the neighboring base stations to avoid any inference issues in the affected areas and possible handover failures
Q: Do you have any parting thoughts as we conclude?
Cliff: Operators, and the local governments need to plan ahead for situations where communications may fail . Wired mobile backhaul is often vulnerable to disruptions, so wireless alternatives such as satellites and microwave can be considered in the contingency plan and each BTS/NB and eNB stations should have a redundancy solution in case one of the backhaul transmissions fails
In this case, even though the mobile network was restored, the fact that a commercial network had to be used by the emergency services as a communication tool due to the collapse of the TETRA network concerns me. Although we did not get any reports of this, it was entirely possible that the first responders may have encountered busy network problems.
Compared to the TETRA networks, in Europe, it is the mobile operators that owns the most robust and ubiquitous networks. Therefore, there needs to be concerted efforts by governments, operators, emergency services to assess the role of mobile operators and their ability to provide 'mission critical' communications between emergency services and first responders in moments of life and death. Basically, the open questions: (1) should public safety communications be part of the mobile operator remit? (2) does Europe need to consider Public Safety Networks over LTE 700/800MHz as an alternative/complement to TETRA?
In this Portugal forest fire tragedy, we learned that a modernized warning system to inform the public and a robust communications system for public safety are things that cannot be compromised on.