TETRA has been slow to catch on in North America for regulatory and commercial reasons, but is starting to come into its own. TETRA Today looks at some of the highlights from the TETRA Congress Americas event in Dallas, Texas
Public safety could be argued to be the last frontier and the great prize for TETRA in the US mission- critical comms market. Steve Macke, principal at Advent C3, notes that: “Harris County in Georgia is sharing Diverse Power’s TETRA infrastructure, so there are already public safety agencies using this technology in the US. I think gradually that ‘ah-ha moment’ will become clear because when a local government compares TETRA against DMR they’re going to see that not only [does TETRA] have a faster set-up time (sub-300 milliseconds), they’re also going to hear the better audio quality and see the economies of it. It’s faster, it’s cheaper and it’s better.”
Dean Ginn, founder & CEO of Dean’s Two Way Radio (which installed the system) was on hand to provide more details. He explained that Diverse Power, a local electric membership corporation (EMC) came to him initially because it had a PT system in the 220 MHz band with no options for data that was at the end of its life-span. It had Part 22 channels, which can be used for TETRA, so he and his colleagues started doing some research. “Over the course of two years we now have 17 sites, and we’re expanding to 40 sites by the end of January,” Ginn says, adding that “the EMC wanted to invite the public safety sector in. So we brought in almost 1,000 radios for public safety – fire, EMS and the local sheriff’s department.”
He explains that when the public safety organisations migrated to the TETRA network from a voice-only SMARTnet system they immediately gained GPS, “which was huge for them” and did not come at an added cost as it was built into the network.
“Our objective was to build an interoperable radio system for Georgia. We have about 51 per cent of the state with RF coverage so we’ve got a lot of opportunities,” Ginn says. “[For emergency services] it saves the dispatcher having to ask ‘where you at?’, he sees where they are. For automatic vehicle location it’s very powerful if you have a GPS solution that tells you when a fire engine leaves a station. We did not have [these features] with any of the legacy systems or any of the current DMRs that were coming up. TETRA is very robust and has met our expectations.”
P25: lacking a migration path to LTE
In this market some discussion of P25 is inevitable, given its status as the incumbent for public safety and the sector’s size. According to Jose Martin, CEO of PowerTrunk, one factor that will influence the direction of P25 is the Federal Communications Commission’s (FCC) decision to eliminate the narrowbanding requirement for the 700 MHz band, which is due to come into force in December 2016.
Martin adds that because of this situation P25 Phase 2 may have arrived too late and notes that the FCC-defined interoperability requirements refer to Phase 1, not Phase 2. He suggests that Phase 1 systems will remain for a long time as a result. Martin believes that the market is not prepared to renew all the existing Phase 1 systems and migrate to Phase 2, because “Phase 1 and Phase 2 are completely different technologies, there can be no migration, it will be a total replacement.” He also notes that Phase 2 requires an additional 12.5 kHz control channel for backwards compatibility, “which makes it inefficient in terms of spectrum usage”.
“In the event of TETRA being used for public safety in this country, the terminals would be much more affordable [as it would be] a real competitive market. And when I say very affordable I mean that the subscribers [would be] sold under $1,000, in many cases even way under $1,000. Presently for public safety P25 radios are sold for $7,000,” Martin says.
Peter Clemons, managing director of Quixoticity, notes that as the big TETRA players are active in 3GPP,the TETRA to LTE migration part is much clearer than the same path for P25 migration, while Macke says that there isn’t a migration path from P25 to LTE.
Andy Schwartz, director of radio communications & elec. security systems at New Jersey Transit (NJT), ran through his experience with TETRA as an early adopter, and how multiple agencies communicate with each other during a large event in the US.
Currently NJT uses TETRA at 800 MHz for light rail, private carrier operations and bus operations (the latter also uses 800 MHz FM via CAD and UHF conventional FM). Its rail operations use VHF NXDN, and VHF/UHF conventional FM. In addition it works closely with the local police department, which also uses TETRA at 800MHz, along with VHF conventional FM, and 7/800 MHz P25 Phase I/II.
To allow interoperability NJT broke all of the above down into analogue baseband voice, digitised it and then brought it onto its enterprise network with QoS, using a common radio-over-IP (RoIP) platform/gateway. A common console interface, four-wire tone control, is used to access the RoIP network, or a native RoIP interface where available, such as Telex and WAVE.
“We put this into production for the Super Bowl, and more recently we used it for the New York City and Philadelphia visit by Pope Francis,” Schwartz says. “From one [dispatch] console I had access to radios that are TETRA, P25 – basically all technologies, all frequency bands, all brought into a common place using the radio-over-IP technology, which essentially nullifies incompatible frequencies and incompatible technology. It brings it down to a common level, which makes it accessible throughout the enterprise. From a radio perspective you get complete situational awareness.”
He adds that NJT also makes use of applications that allow its staff to talk to radio users on their smartphones. “All these technologies and frequencies can be brought into your smartphone. It does rely on cellular data so I wouldn’t call it mission-critical, but it’s a very effective way to integrate multiple technologies.”
“TETRA can be interoperable. Interoperability is not a valid argument against TETRA or any other non-P25 technology, certainly in the transit or utility market. TETRA can be easily integrated into an environment where multiple technologies and frequency bands are used. Business and operational needs should drive technology selection – one size does not fit all.”
Turning to his views on interoperability, both in the US and for NJT, Schwartz says that: “Interoperability is based on something of a false premise – that all users and agencies need to have the ability to talk directly to each other during an incident requiring a multi-agency response, or even during day-to-day operations. It sounds good and it may apply to certain operations and agencies but the reality of how it works is a bit different.”
He explains that his organisation’s operating partners use a wide variety of technology and frequency bands. “We have police running on P25, fire on conventional FM at 450 MHz, emergency medical services on VHF and FM, and NJT’s operations running TETRA. Unless you have a radio that can work across all bands and all technologies direct radio-to-radio communications are not something that can be realised in all situations, nor are they practical.”
Schwartz adds that: “If everybody could speak with everybody at will communications at an incident would be unmanageable, nobody would be able to effectively communicate or manage the situation.”
In the US the Incident Management Information Sharing (IMIS) process guides how organisations communicate during incidents. One of the practices it mandates is the creation of an incident command, which will be made up of representatives from all the responding agencies, including transport operators. Consequently, interoperable communications occur at the command level, usually face- to-face. Once decisions have been made unit leaders will then relay them to their colleagues using each organisation’s own radios and radio frequencies.
TETRA in the city of angels
John Monto, a director at Rockwell Collins, describes his experiences from the installation of the first US airport TETRA system at Los Angeles International Airport (LAX). He explains that the main driver behind its take-up of TETRA was the announcement of end of life for iDEN and the need “to bring our customers something that was going to last for a long time”.
Some of the benefits of TETRA for airports include the fact that it reduces the number of devices needed per person for operations and comms, while “at the same time giving you a network with the maximum throughput for voice or data”.
“The conversion to TETRA at LAX went very smoothly. We really sat down and took a hardline approach on how we wanted to balance the system; we looked at the areas of coverage we needed,” he says. “There was a lot of engineering done on the backend side, but when the rubber hits the road and the system was turned on it worked.”
He adds that the full benefits of the system have yet to be realised as they are still working on the applications side of it, noting that it’s a very traditional voice push- to-talk environment. Monto expects the introduction of applications is going to “bring a lot of return for the user”. He accepts that this will make staff training an issue, in that users will have to learn that applications can be more efficient than voice. According to Monto, airports are deploying more and more applications. “Automatic vehicle location is a huge one. Knowing where people are in relation to each other and aircraft is critical.”
He also notes that the ability to automatically create groups on the fly is very important, as “it takes about 200 people to get an aircraft off the gate. Every time you go to a different gate it’s a different subset of people, so those people are constantly crossing paths and re-aggregating themselves into different groups.”
TETRA for utilities
Klaus Bender, principal engineer for Site Safe and former senior director of standards & engineering at the Utilities Telecommunications Council, gives his views on the use of TETRA by utilities for data applications. He believes that the main reason utilities in the region are considering TETRA is that they are “putting critical command instructions on unlicensed spectrum because they can’t get the frequencies they need to operate this kind of system and they can’t afford to use a wireless carrier to do it for them”.
“Some of the things utilities need to keep the network operational you can’t do with TETRA, you can’t do with anything except fibre, but there are countless applications that have that one second, two second, 10 second turnaround that TETRA is beautiful for,” he adds. “I think in the end what is most critical is the channel data capacity.
“The myth that TETRA is only for urban markets is not true. If you want to define TETRA over a large, relatively rural area all you have to do is build it out at design. TETRA allows for voice and data in a single path.”
Bender says that one issue for North American utilities is that it can be difficult for them to recover the cost of spectrum from a secondary market through the rate payers. “If they don’t have the money to afford it up front they often can’t pass on those costs to the customers via a rate increase, because often the regulators don’t understand the importance of the communications system.”
He warns that there is a move under Part 90 to drop 12.5 kHz channels in between the 25 kHz channels that are in the 800 MHz band and suggests that utilities keep an eye on this as it poses the risk of adjacent channel interference on channels that were once exclusive.
Nick Smye, chair of the TCCA’s SCADA Working Group, says: “You don’t want to connect your SCADA host via radio if you can possibly avoid it, you want to connect directly into the TETRA switch otherwise you have another air-interface, delay and a capacity bottleneck.
“The key thing for SCADA today is that the applications need security, reliability and guaranteed bandwidth. You don’t need megabits but you want something secure and TETRA does that really well. TETRA is here to stay, LTE is not going to take this away in the short term,” he concludes.
TETRA vs. Opensky
A member of the audience asks the panel to compare Harris Corporation’s Opensky technology with TETRA. Phil Kidner, CEO of the TCCA, emphasises the fact that Opensky is a proprietary technology and therefore it is not possible to pick and chose equipment from different manufacturers, while with TETRA you can choose different types of radio for different applications and on other criteria such as availability.
PowerTrunk’s Martin points out that TETRA is more advanced as it uses linear modulation (Opensky is non- linear), resulting in much higher data throughput (36 kbps versus 19.2 kbps on the same bandwidth). He also says that with Opensky it is difficult to recognise the speaker’s voice – a key requirement for mission-critical applications and public safety.
Jim Medlock, a radio communications expert, explains that OpenSky was originally developed for FedEx so voice was a secondary consideration. Its voice capacity was sufficient for trucks and dispatch, but degrades rapidly in the kinds of noisy environments typically encountered in public safety and construction applications. He also says that “[OpenSky] is a mature technology so you’re not going to get anymore of it”.
Keith Ammons, director of the North America TETRA Forum (NATF), gives an overview of TETRA’s current presence in the region, adding that in 2016 “we hope we break the 40,000 terminal mark”, and showed some of IHS’s predictions for the market, e.g. annual TETRA terminal sales rising to around 90,000 units by 2018. Ammons explains that NATF is a vendor-neutral, non-profit organisation that aims to promote TETRA as “a viable technology for this market”. “We are looking to increase our activities and our membership. We’re planning a couple of digital roadshows and participation in conferences [in 2016],” he concludes.
The discussion from TETRA Congress Americas highlighted TETRA’s entry into the US public safety market and the potential cost savings that organisations will see once it becomes fully accepted by the sector. It also highlighted the fact that interoperability considerations are not a true barrier to TETRA’s use, the benefits it brings to both utilities and airports, and the advantages of using it instead of proprietary technology.
