The convergence of 3G and 4G private mobile networks and LMR radio communications remains a key talking point in the public safety industry. It has been a primary conversion during industry trade shows, APCO meetings, association gatherings, and in police, fire, and EMS command centers.

Even though broadband LTE networks have been around for about a decade, it may come as a surprise to many that the analog to digital transition has been a bit of a slow move and is still in process. Digital systems didn’t overtake their analog counterparts until 2017. While LTE devices used in the mission critical sector are still only a fraction compared to LMR radios, the projection is that in the next 10-20 years LTE will become the go-to mission critical technology.

As public safety networks evolve to meet the growing demands of mission critical applications, LTE and LMR will coexist for the next decade or two. Ensuring such systems can operate as they should in life-threatening situations will be challenging, as a result.

LTE Growth in Public Safety

There are a few reasons why LTE is making its move in public safety networks:

Standards Development – Mission critical communications LTE standards are developing quickly, with elements to meet the market needs being passed. Release 13, which was completed by the 3GPP in 2016, addressed the key issue of reduced latency, as well as enhancements to machine-type communications, and single cell point-to-multipoint. In 2017, Release 14 was approved and it further enhanced mission critical push-to-talk capability as well as mission critical data and mission critical video.

Data-intensive Requirements – Many public safety tasks require broadband services, such as when first responders need to access data-intensive applications, search databases, or share video or images. For example, an engine company is dispatched to a burning building. With an LTE network, the command center can send the fire fighters a floor plan, so they don’t enter the burning building blind.

LMR Still has a Voice

Despite the growth of LTE, LMR still has a strong presence in public safety networks, and that will continue. Despite the data advantages provided by LTE, there are technology trade-offs. For one, to ensure the high data rate associated with broadband networks such as LTE, the frequency spectrum used must be increased. The result is lower power, shorter range and less resistance to interference. Because of this, narrowband LMR is preferred for rural areas where these considerations are essential.

What this all means is that LMR is not going to be replaced by LTE in the near term. Cost, not surprisingly, is another reason why LMR will remain relevant. Many LMR operators have just finished converting from analog systems to digital systems such as P25, TETRA, and DMR and don’t want to invest in a new technology so quickly. Plus, for LTE networks to provide the same coverage area as an LMR system, operators will need to install many more cell sites closely together, resulting in higher equipment and maintenance expenses.

Making Test Cost-Effective

Carrying multiple instruments into the field is not ideal. Not only does it add cost to deploying and maintaining networks, it requires field technicians to learn and be adept with separate test equipment. The Anritsu LMR Master™ S412E is a battery-powered LMR field analyzer capable of supporting the complexity of testing LTE networks and mapping bit error rate (BER) and modulation fidelity of LMR networks.

The handheld analyzer combines many of the tools needed to install, maintain, and certify LTE and LMR systems into a single instrument with a common user interface. This gives technicians and engineers responsible for public safety communications systems confidence that these networks will work as expected.

Wayne Wong is the product manager for the LMR Master product at Anritsu Company. He has held various roles from Senior Hardware Design Engineer to Field Applications Engineer during his 20 years in the Test and Measurement industry. Wayne earned his Electrical Engineering degree from San Jose State University.tions Engineer during his 20 years in the Test and Measurement industry. Wayne earned his Electrical Engineering degree from San Jose State University.