Rural radio - Victorian firefighters join the digital age

Firefighters in country Victoria now have access to a digital radio system.

In May 2013, Telstra won a contract from the Victorian Government to roll out a new radio network - the RMR, or Regional Mobile Radio network - for the Country Fire Authority (CFA), to replace the analog system that had been in use. The RMR network is owned and operated by Telstra and runs base station sites equipped with Motorola P25 equipment.

The primary aim of the RMR, which went live earlier this year, is to connect all of the regional fire brigades back to the Emergency Services Telecommunications Authority (ESTA), which operates the triple-zero dispatch system.

Telstra also owns and operates the Statenet Mobile Radio, or SMR, network, which uses TaitNet MPT hardware. The SMR network has multiple users, including Victoria Police, Ambulance Victoria, the Department of Environment and Primary Industry, as well as the SES and other agencies.

“We’ve been running SMR for a couple of decades,” said Daniel Chivell, Telstra’s System Architect for Managed Radio in Victoria. “We run the Emergency Services Managed Radio side of the Telstra business, and we look after most of the emergency services voice comms in country and regional Victoria.”

Department of Defence photo.

While there are already around 120 sites in the SMR network, the addition of the RMR network brought the total to almost 200 sites.

“We had the SMR network and we knew what the coverage was from those sites,” said Chivell. “But because of the new P25 base stations, we needed to survey each of the sites to demonstrate the required service performance levels.

“We have very sophisticated radio coverage prediction tools. And so we had predicted what coverage we would get from each site and then the combined coverage across the state,” said Chivell. “We then had to prove that what we had built was what we had promised the customer.”

Unprecedented scale

The Wireless Network Engineering team needed to survey not just the signal strength but also the voice quality, a bit error rate, from multiple sites at once. They needed to survey the sites over a period of only a couple of months, which required the teams to drive tens of thousands of kilometres through country Victoria.

“We set up a standard car that we calibrated with an antenna in exactly the right spot, according to our agreed testing methodology,” said Chivell. The base stations are Motorola equipment and Tait radios were used in the survey vehicles.

“We had up to three survey cars out at any one time,” said Chivell. “We even had to have multiple shifts of drivers, because you only have a small amount of time between when your sites are built and when you have to have them completed by.”

The teams began surveying in December 2013 and finished at the end of May 2014.

The survey team covered approximately 35,000 kilometres along rural roads.

So how did it go? “Very, very well,” said Chivell. “It was the first time anyone in the world had surveyed a P25 network on this scale. Normally, when people survey networks they do one site at a time, or small counties and districts. No-one had surveyed on an entire state level before.”

Chivell has high praise for the survey team. “The Drive Survey team was managed by a very capable graduate engineer, who became known simply as ‘The Stig’,” said Chivell. Overall, they visited hundreds of CFA fire stations, endured five flat batteries, three breathalyser stops, one flat tyre and far too many coffees and bacon and egg muffins.

Software saves the day

To ensure the networks were surveyed to the required standard and completed on time, Telstra enlisted the aid of a US company called Survey Technologies Inc (STI), which produces network survey software.

“A few years ago, I was at the Comms Connect exhibition hall and bumped into STI and saw their software,” said Chivell.

STI’s software had the ability to measure up to four sites at a time, but Telstra needed more than that. The CFA network comprises 16 districts, and they needed to survey entire districts at once. Each district could be served by over 20 individual sites.

“We didn’t want to have to drive the same road multiple times, as one road might be served by three or four sites,” said Chivell, adding that historically it had been easier with the SMR as “we’d only ever surveyed one site at a time, because we had built it over such a long period of time”.

So Telstra went back to STI and asked them to develop a BSQM, a best server quality measurement. With BQSM, one of the radios was set to scan up to 20-plus sites and find the top three strongest channels. The system then assigned those channels dynamically about every second to three other radios. Those three radios would then simultaneously survey the three sites.

“What that enabled us to do was we could drive down a road knowing that we had one radio that was looking at all of the sites in the district that we needed to survey, and at every moment picking the top three,” said Chivell.

“We would set the base stations to broadcast a digital test pattern. Being a digital network, we had to measure a bit error rate from the sites - so while the first radio was doing a fast scan, the other three radios were measuring the bit error rate because that takes more time and calculations.”

Having STI based in Oregon was no impediment to their support of the equipment. “We had several times when we required assistance configuring the gear. We were able to set up a remote desktop session between the computers running the survey gear and STI. We’d organise a hook-up at 8 am our time, which was afternoon their time, and they’d log on and take direct dumps of the error messages and give us the solution the next day,” said Chivell.

“There are various case studies of what other people have done elsewhere in the world, and as far as we can tell, nobody had ever surveyed a P25 system on this particular scale before,” said Chivell.

A couple of thousand kilometres north, Telstra was working on another similar network.

“They had the same problem as us - they needed to survey quite large areas in a short amount of time,” said Chivell. “The guys up there used the same survey gear. Even though it’s a UHF network and has some slightly different parameters, they were able to use the same STI survey gear with a few tweaks.”

The end result

Improving CFA communications was a key recommendation of the Victorian Bushfires Royal Commission.

With more than 60,000 members - 98% of whom are volunteers - the CFA is one of the world’s largest volunteer organisations. Prior to the establishment of the RMR, 45% of its brigades could not directly contact ESTA and had to relay messages through base station operators.

The new system “will allow brigades to speak directly from the fireground with emergency call centre operators at the three State Emergency Communications Centres, reducing the risk of communication failures and improving safety for both CFA members and the public,” said the Victorian Minister for Police and Emergency Services, Kim Wells.

“It will also improve communication between agencies such as Victoria Police and Ambulance Victoria and ensure a consistent approach for the dispatch of CFA brigades and Vic SES units.”

Department of Defence photo.