By Philippe Agard, Vice President for Public Safety with Alcatel-Lucent, and Philippe Devos, Vice President Market & Technology, Secure Communications Solutions at Cassidian

Public safety agencies and associations now broadly agree that 4G Long Term Evolution (LTE) is the right technology for bringing mobile broadband capabilities to emergency services across the globe. The question now seems to be which parts of the frequency spectrum should be allocated for public safety LTE. But while the US has already set aside a portion of the 700MHz band, the rest of the world is still in heated discussions.

And no wonder. The governing bodies responsible for frequency allocation across all users – be they military, commercial or governmental – must consider and balance many important considerations, and any refarming of frequencies will always result in grinning winners and disgruntled losers. Setting aside national security issues, which are understandably non-negotiable, there are perhaps three primary arguments to consider:

• The first is economic; moving to a new frequency band, let alone a new technology, requires significant investment for those affected.
• The second is technological; frequency is directly related to features and capabilities of radio communications such as propagation, penetration, power consumption and interconnectivity with existing systems.
• The third is commercial; spectrum allocation influences the number of manufacturers choosing to provide network equipment and terminals for a given frequency, which in turn affects pricing and availability.

Watch a demo of Evercor, an integrated LTE 400 PMR solution:

A strong contender for Europe, many Asia-Pacific countries and some parts of South America, is of course the 400MHz frequency band currently used by public safety agencies for their TETRA and TETRAPOL communications systems. Looking at the three criteria described above helps clarify the strengths of the 400MHz band.

• In economic terms, public safety agencies have made considerable investments in 400MHz TETRA/TETRAPOL networks. By using the same band for public safety LTE, agencies will be able to re-use existing sites and assets such as masts and backhaul, which minimizes investment costs for adopting this new technology. So LTE can cost-effectively be integrated with today’s TETRA networks without disrupting operations. This single network evolution strategy leverages TETRA or TETRAPOL mission critical features with new LTE broadband capacity for the delivery of new applications.

• The propagation characteristics of signals around 400 MHz mean that coverage of a given area can be achieved with the same number of radio sites as current narrow band networks. Penetration in built-up urban areas, including indoor coverage in difficult places such as stairwells, is also better around 400MHz than higher frequencies and also more efficient for rural coverage. So using the 400 MHz band together with higher power base stations and radio terminals would allow the introduction of LTE services matching the cell edge of existing TETRA or TETRAPOL sites, meaning a better cell range and coverage – in other words, lower implementation costs per user. The technological advantages of 400Mhz also provide economic benefits.

• Commercial viability requires an ecosystem of partnering and competing equipment manufacturers to develop solutions to a scale that makes business sense to them, at costs and conditions acceptable to public safety organizations. Addressing at the same time commercial opportunities in industries with similar needs, such as the Energy and Transportation sectors, will improve the viability for all, as will addressing the 700MHz spectrum already allocated in the US. The joint development agreement between Cassidian and Alcatel-Lucent is leading efforts in this respect for a commercially available TETRA/LTE solution operating at 400MHz. The two companies are also suggesting a step by step refarming process of the 380-470MHz frequency band, to free additional spectrum in the near future.

The significant benefits of public safety LTE – operational effectiveness, cost efficiencies and, ultimately, the safety of field personnel and the public they serve – are now very close to being realized. To find an analogy, the industry has chosen the car they want to drive; but outside the US it’s still debating a diesel or petrol engine. The imminent first commercial solution at 400MHz could finally bring the debate to a close.

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The promise of mobile broadband for public safety

The data handling capabilities of LTE allows public safety personnel to take advantage of innovative new applications for real-time information sharing and collaboration during emergencies and day-to-day operations. These promise to improve situational awareness and enhance the safety of first responders and the public. Some of the possible uses are:

• Real-time, two-way video in vehicles or on hand-held devices
• Multimedia command and control data such as floor plans, incident stills and surveillance videos
• Digital signage such as traffic alerts and automated transactions
• Remote database access to mug shots, finger prints, medical records, etc
• Geolocation services, such as online maps and personnel or asset tracking