LMR Will Continue Alongside LTE
By Tim Rock
Tuesday, June 18, 2019 | Comments

SMR technology was revolutionized by Nextel Communications when it established its digital system in 1987. With its overwhelming success, Nextel continued to build out sites throughout the United States and expanded worldwide using an LMR-based system developed by Motorola Solutions.

Sprint purchased the network in 2005 but found that the technology was too costly to maintain. Sprint and other carriers tried to duplicate the push-to-talk (PTT) over cellular (PoC) model as Nextel had done. Most were unsuccessful, and digital SMR systems were created with large, continuous coverage areas. SMR technology is generally radio only but provides a stable system for communications.

As Project 25 (P25) became a public-safety standard after 9/11, many states used this technology for interoperability among themselves and departments nationwide. The cost was considerable, but reliable, full-featured emergency communications directly enhanced the lives of all public-safety personnel. Public safety requires and demands 95% in-building coverage, yet most cellular providers find this unachievable.

The First Responder Network Authority (FirstNet) can provide the needed bandwidth for data applications with dedicated band 14 frequencies allocated for public safety. The concern is whether or not we can rely on a large telephone company to use the frequencies exclusively for public safety or make use of them when communications is slow and the question of profit is introduced.

So, when a gun is pulled or a fireman hits the PTT, the system has to work. Cellular-type systems cannot guarantee this. Bidirectional amplifiers (BDAs) must be added in large buildings for PoC devices to work, and yet, if the building is on fire, there is no guarantee that the fire will not destroy the on-site BDA. I don’t know of any firefighters, EMS or police personnel who are willing to take that chance.

On the contrary, LMR radios can perform a direct radio-to-radio call and bypass all infrastructure if needed. FirstNet and other PoC networks can’t. LMR has the capacity and solutions to ensure that the PTT call will go through. As carriers compete for spectrum, the availability for bandwidth will shrink exponentially. The cost for public safety does not have to be in the millions of dollars. With more competition, prices have decreased and are more affordable than ever before.

The Role of PoC
PoC will provide a reliable and stable market for business and noncritical systems. But because coverage relies on cell towers, high frequencies do not penetrate most large schools, business and hospitals because of the way new building codes are written. LMR specializes in high-power units, while cellular device are low-power units.

Most schools do not have needed cellular in-building coverage. LMR suppliers can provide statewide SMR systems that work on UHF and other frequencies that can penetrate large buildings, allowing users to respond immediately in an emergency, giving workers, administrators, and first responders immediate access through the PTT functionality.

With dedicated channels for SMR and public safety, the question of capacity in the event of an emergency is key. With 1,500 kids on a single site calling or texting their parents and friends during and after a school shooting, for example, how reliable will cellular service become? SMR and P25 have radio-to-radio simplex and microwave SMR systems that do not rely on cellular’s weakest link — the internet.

The argument that LMR is too costly is unfounded. LMR is less expensive, requires less overhead, has a smaller global footprint and offers lower maintenance costs than cellular. SMRs do not offer nationwide coverage, but that is the strength of its effectiveness. To penetrate most buildings, coverage must be local. This is what makes LMR so dramatically different and uniquely reliable.

Cellular systems require many tower sites, rooftop sites and power towers. LMR systems can use tall broadcast towers to carry their signal much farther. Cellular’s low-power devices require a massive buildout. During the past 10 years, local governments have prevented the buildout of cellular towers, making it difficult to cover the cities, let alone the often overlooked rural areas.

As China and other countries continue to hack into cellar-based systems, it’s just a matter of time before these networks are compromised. Digital LMR technologies, such as P25, NEXEDGE and Digital Mobile Radio (DMR) are difficult to hack and will be around for many years to come. A number of analog systems will also continue their operations throughout the United States.

PoC services are effective for non-mission-critical applications such as administration and logistics, but critical businesses and public safety need reliable critical communications. With POC solutions, you may be a third- or fourth-tier consumer. If your business takes place near major cities, POC may not work during large events. During disasters, SMR owners can focus on a handful of tower sites and infrastructure, while POC relies on a system of hundreds of sites in an area that may take longer to repair. Remember all calls will be answered in the order in which they were received. Cell sites will be put back in service based on what makes the carrier’s bottom line profitable.

This story is part of a two-part point-counterpoint series about the future of LMR and LTE.
Click here to read the other viewpoint.

Would you like to comment on this story? Find our comments system below.

Tim Rock has 37 years of experience in LMR and SMR systems. He operated one of the first SMR mobile phone systems in the late 1980s before cellular existed in the Charlotte, North Carolina, area. Rock has experience in paging, telemetry and tower sites and provides state-of-the-art systems to major hospitals, football stadiums, large manufacturing facilities, theme parks, zoos and public safety. FleetTalk by Rock Communications is one of the largest SMR digital networks in the Carolinas with partners all over the U.S. More than 85 seamless roaming systems in the Carolinas provide businesses and public safety an affordable and reliable solution. Guaranteeing 95% in-building coverage where needed, Rock plays a major role in the safety of more than 25 school districts, providing a one-button emergency call to all schools and personnel in their school districts and busses statewide. The FleetTalk systems have GPS tracking, as well as texting, private calls and group calling. For more information, visit http://www.fleettalkbyrock.com.

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On 7/18/19, CJ Hicks said:
There is a fundamental difference between public safety LMR and cellular. Public-safety LMR is built to maximize reliability and access cellular is built to maximize revenue. You cannot reconcile those two things. A hardened public-safety radio site is much more costly than your average cellular site. Omitted here is cost of terminal equipment and any discussion on dispatch systems.

On 6/20/19, Leon van der Linde said:
I do agree with Tim Rock. Cellular systems have not been proven reliable. The network is the first thing that breaks down during a disaster. I cannot see how a cellular provider can give a first responder priority when all his paying customers want to make calls.

LMR is reliable and has proven to be reliable. Unless FirstNet builds its own network, I see dark times. POC is OK for data and videos, but when it comes to hardline communications, the radio will still rule superior.

On 6/18/19, Ronald Durie said:
Very good article Tim. Very informative when trying to figure out all the available options with their advantages and disadvantages. It looks like Fleet Talk is well situated with excellent safety-critical advantages.


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