Public safety interoperability: Where are we now?
It’s been years since APCO came out with standards for Project 25. Project 25 was designed as the great equalizer that would lay out a universal, uniform digital two-way radio technology for public safety agencies at all levels. As we roll over the century, it might be a good time to revisit some of the issues that have been addressed and some that still need to be resolved.
Seamless, effective, efficient and reliable intra-agency and inter-agency communications: Wouldn’t it be great if every law enforcement and related public safety agency had the ability to tap into the mega-crime and resource database that is the real-time, worldwide chronology of crime? Public safety officials, from a sheriff in any sleepy little town reminiscent of Mayberry, to the L.A. county police chief, and on to the director of the Federal Emergency Management Association (FEMA) could all have up-to-date and accurate data. Such data would be the ultimate weapon that could weave an interconnected, national dragnet. Or it could be the one universal source to minimize delays and provide precise and immediate implementation of full-service emergency management teams in times of disaster. Any critical public safety service with true interoperability (police, fire, EMS, hazardous waste, government) can be patched in and out of a situation as easily as bringing it up in a command center computer’s window.
Sound melodramatic? Maybe so, but what about the story that hits the paper about a heinous criminal being let go after a routine traffic stop? Or how often are critical, life-saving services delayed when precious time elapsed because interagency contact systems are not compatible or all the protocol isn’t followed.
It’s still a major issue because speeches are given at lots of conferences, public safety and others, addressing interoperability. NPRMs (Notice of Proposed Rulemaking) have been released by the FCC addressing public safety interoperability, and Congress has issued a mandate to reallocate spectrum for public safety interoperability. Still, progress is slow, and not everyone is entirely happy with some of the non-technical issues surrounding interoperability. There are lots of players, other than police agencies, that have an interest in interoperability, as well.
Intricacies Interoperability not only deals with equipment, it deals with spectrum and politics, as well. Public safety entities are notorious for wanting to keep both control and confidentiality intact on their communications channels. So, while there is the realization that interoperability is, ultimately, a must, there are a lot of issues, some key, that are a long way from resolution.
Depending on who you talk to (the FCC, APCO, local police agencies, IAFC or local fire command centers, life-safety, fish and wildlife, the forest service and even the International Municipal Signal Association (IMSA) for example), their priorities vary. Some are concerned with spectrum, others with technology (video, data, global positioning systems [GPS], automatic vehicle location [AVL]), etc. Others focus on loss of control. So there is still no single solution on which everyone can agree.
To muddy the issues even further, some peripheral agencies want a piece of the interoperability pie as well. In times of uncommon emergencies (forest fires, floods, severe weather, acts of terrorism, earthquakes, etc.), agencies such as the National Weather Service, forestry services, the Federal Energy Management Association (FEMA), the FBI, highway departments (state and federal) collectively, or individually, need to be included in wireless communications. A few major issues garner the lion’s share of the debate.
Spectrum Perhaps the most challenging of the issues is spectrum. Currently, most of the police, fire and EMS communications is below 512MHz, with most of that at the high end of VHF. Of the remainder, the majority are in the 800MHz band. So of course, the issue of interoperations frequencies means different things to different agencies.
Depending on whom you speak to, there is demand for interoperations frequencies in the 380MHz to 400MHz band because it is easy to integrate these into current UHF public safety bands. There is also interest in freeing spectrum at VHF (174MHz-216MHz, which is currently occupied by TV channels 7 through 13). Others are seeking spectrum at the upper end of the UHF band (470MHz-512MHz) with the argument that this is already a shared band in some metropolitan areas. The National Telecommunications and Information Administration (NTIA) wants to see some interoperations spectrum at 138MHz-144MHz. And finally, other agencies are looking for frequencies at gigahertz bands (1,700MHz and 4,600MHz) for wideband applications such as video and high-speed data. (Did I miss anyone?)
One other significant concern is that there won’t be enough bandwidth, no matter what.
Recent reports from entities such as the NTIA and the Public Safety Wireless Advisory Committee (PSWAC, now superceded by PSWN), and APCO, are concerned that current spectrum allowances won’t meet the needs much beyond the first decade of the 21st century.
However, regardless of white paper, industry bickering, petitions, comments and predictions of doom, interoperations spectrum is an issue being tackled by both Congress and the FCC.
Over the years, there have been spectrum allocations in various bands. Recently, some spectrum in the 800MHz band (821MHz-824MHz and 866MHz-869MHz) was allocated for interoperability. But it was turned over to planners at a regional, rather than a national level and problems typical of splintered planning arose. There were issues such as whose regional rules would apply in boundary overlap, who would monitor overall system interoperability, which service got interoperations frequencies and which didn’t (priorities varied from region to region), among others.
So now, in its latest move to follow up on Congress’ mandate, the FCC has allocated 24MHz in the 700MHz band for inter-operations frequencies. This is probably the most aggressive attempt, to date, to bring wide-scale interoperations spectrum, as well as additional general spectrum, on line.
This allocation consists of 24MHz of spectrum at the upper end of 700MHz: 12MHz between 764MHz and 776MHz and 12MHz between 794MHz and 806MHz. The commission wants part of this for interoperations frequencies and part of it for general use by public safety entities. Furthermore, the mandate also calls for equipment used on these frequencies to be digital, and this is one of the issues that makes this most recent spectrum allocation so interesting.
Digital equipment Much, if not all, of the new equipment and technology coming on line has to be digitally based. Advanced information distribution and acquisition (predominantly video-both static and real time) is a bandwidth hog. Digital technology can employ compression, conversion, rerouting and other manipulation processes that analog cannot, and it will be required to squeeze the most efficiency out of the spectrum.
There are other technologies, such as AVL, GPS, encryption, mobile data terminals (MDTs), mapping, vehicle-mounted and remote video acquisition and advanced EMS telemetry for which the interface equipment and technologies need to be forward- and backward-compatible. All of this will demand sophisticated coding and routing schemes that can only be implemented in a digital infrastructure. Such equipment is much quicker to come on line and much more compatible if there is a clear standard to develop it under.
One direction is to integrate an interoperable system into current analog systems. Some functions, such as voice communications, could remain on analog frequencies that are already in use. The new interoperations frequencies are then used for enhanced services, like video, that require lots of bandwidth.
As with all grand plans, there are a few issues on the downside; cost is often mentioned. Small, analog, and low-need agencies that have VHF and UHF equipment and frequencies can face severe cost issues if everything suddenly has to be upgraded to a digital 700MHz system. Another issue is technology compatibility. Some platforms, like PCS, mobile data, satellite imagery, etc., are digital from the ground up, and cannot operate in analog environments. Further, digital equipment is inherently nasty to neighboring, sensitive analog RF equipment.
Engineers involved in equipment design certainly have their work laid out before them, especially to marry analog and digital technologies.
Politics (and other issues) One of the hottest political issues is the frequency control debate. Consider that there are more than a dozen entities (APCO, IAFC/IMSA, FCCA, AASHTO, et al.) that currently control frequency allocation. Add to that the number of local and regional coordinating bodies, and the cauldron is ripe for a slugfest. It is painfully clear that there has to be a top-level entity that is responsible, and politically neutral, to oversee this, and future allocations. Arguments have been presented that there should be one, supreme agency that is a collective, cooperative group comprising the current recognized frequency coordinators. This body should have the full responsibility, and accountability, of doling out these new frequencies, as well as resolving issues as they arise.
When it comes to spectrum, one can always argue centralized vs. distributed control, but spectrum has the same properties everywhere. Use of spectrum may be allowed at the local level, but control needs to be at the national level.
Another concern is bandwidth availability for the needs of a particular agency. Further, there is no clear-cut answer to the question of what to do with the vacated frequencies (which are often more valuable than gold). Many are concerned that compatibility will be an issue between present and future 700MHz and 800MHz equipment.
There is also some debate that interoperability spectrum should come from the lower end of the UHF band because so many of the agencies are already located there. There is some merit to this line of thinking. With present technology, it would make implementing interoperability easier.
However, from a technological perspective, most of the development of digital technology is at 800MHz and higher, so there is a horse already out of the door. Digital development for products in the under-512MHz group of frequencies has, historically, been slow to evolve.
Now, 700MHz to 800MHz does have problems. Propagation reliability gets better as you go down in frequency. Terrain is more of an issue at higher frequencies, and coverage areas are smaller. But, considering where the technology developments seem to be evolving, it seems that higher frequencies will ultimately prevail.
One final political football that merits a short discussion is the current digital standard that is part of APCO’s Project 25. APCO argues that this standard, which has American National Standards Institute (ANSI)-approved elements, should be the accepted standard.
However, the APCO digital standard was developed during the early days of digital development, and recent advancements in digital technology offer better solutions for “all digital” systems than what is contained in the Phase I standard. Perhaps this is why the FCC chose to require a new standard for the 700MHz frequencies. That is one of the pitfalls of fast-paced developing technologies.
Crystal ball This latest offering of 24MHz goes a long way toward giving public safety agencies additional resources. It also makes great strides toward the ubiquitous interoperability goals. Unfortunately for most, change is painful, or at least, expensive.
The one question that lingers is one that has befallen other industries as well. Congress, the industry associations, the FCC and others concerned probably have a reasonably good vision of the spectrum and the technological needs of wireless technology. However, one need only look at the surprises, especially digital, that other industries have presented us as the technological revolution emerges.
APCO has indicated that the current 48MHz of public safety spectrum will soon be full. It is unreasonable to assume that additional spectrum will continue to be made available without balancing both sides of the equation. A better line of thinking might be to look at the innovations and undulations that are becoming available to wireless communications. One need only look at the impact trunking had on frequency congestion a few years ago.
Now that we are in the digital age, it would be foolish to assume that current spectrum usage will remain static for the next 10 years. As wireless and digital technology evolves logarithmically, there is little doubt that these developments will further increase spectrum efficiency and product evolution.
This doesn’t mean that spectrum won’t be needed. But as devices become increasingly efficient, and technologies become increasing sophisticated, they will allow better spectrum loading. Moreover, as technologies and products such as low-earth-orbit satellites (LEOs) and “three-digit-GHz” radios become reality, new options and solutions will evolve for everyone.
Maybe we can count on innovation, collaboration and technology to ensure that spectrum efficiency, interoperability and public safety are all achievable goals.
After more than three years of intensive research and testing, Sprint has announced a breakthrough in the interoperability of key wireless network equipment. Sprint PCS engineers have developed standard specifications that enable interoperability between two major components of wireless networks-switches, known as Mobile Switching Centers (MSCx) and Base Station (BS) subsystems-from two vendors of CDMA (code-division multiple-access) equipment.
“This significant development will lead to increased competition among network vendors for CDMA service provider business,” said Keith Paglusch, senior vice president of operations, Sprint PCS. “Because providers may be able to choose among more vendors in every market, this will likely lower costs for Sprint PCS and other CDMA wireless service providers when they buy new switches and base station subsystems.”
A BS subsystem comprises a BTS (base transceiver station) and a BSC (base station controller). The BTS transmits radio frequencies over the air interface to wireless handsets, while the BSC manages the radio frequency resources.
Sprint PCS developed IOS, or interoperability specifications, in 1995 to provide precise specifications when linking vendors’ BS subsystems to MSCs. The IOS guidelines have enabled Sprint PCS to narrow the options under the Telecommunications Industry Association standard for interoperability, known as IS-634 (Revision A). While IS-634 is an industry interoperability standard, detailed specifications have not been available within this standard to ensure interoperability between vendors.
“Sprint PCS and its infrastructure vendors have taken the necessary steps to make the great wireless technology of CDMA even better,” Paglusch said. “We intend to bring these specifications to the entire CDMA community to ‘raise the bar’ on the number of benefits that CDMA offers service providers and their customers around the world.”
During the testing in the Sprint PCS Service Integration Lab in Lenexa, KS, wireless calls were completed using a Nortel Networks MSC and a Motorola BS subsystem. Similarly, calls were completed using a Lucent Technologies MSC and a Motorola BS subsystem. Sprint PCS expects to deploy the interoperability software on its network in a field trial before the end of this year.
