9-1-1 Location: Is Perfection the Enemy of the Good?
By Joe Hanna
Monday, December 02, 2019 | Comments
In the early 1990s, the use of cellular telephones moved from limited to the mainstream. As with any disruptive technologies, this revolution in communications came with benefits and unintended consequences. In the public-safety arena, citizens witnessing an accident no longer had to drive to the nearest pay phone — remember those? — to report the event.

While this process allowed for more timely reporting of accidents, emergency communications centers (ECCs) saw a surge in the number of calls related to an incident compared with precellular days. As it became obvious that cellular growth would only increase, public-safety officials began to realize that one benefit of cellular telephones, that of an omnipresent and immediate tool for event reporting, lacked a major benefit of wireline telephones — location information.

Thus, the FCC opened Docket 94-102 to explore the possibility of location technologies for this emerging wireless technology. The rulemaking process was protracted, fractured and occasionally divisive within the public-safety community as technology providers offered various alternatives. Ultimately, a compromise was brokered that allowed wireless carriers to offer quickly deployed triangulation-based services or more accurate handset-based technologies phased in during a longer period.

As the president of the Association of Public-Safety Communications Officials (APCO) International during the final stages of the rulemaking process, I joined with other associations such as the National Emergency Number Association (NENA) and the National Association of State 9-1-1 Administrators (NASNA) to press for a definitive rulemaking process. To be clear, there was not always a consensus among the various public associations regarding the ultimate rules of the report and order (R&O), but the third R&O in 1999 was ultimately based on technologies that had been demonstrated as capable of delivering rudimentary location.

Over the years, wireless carriers have continued to use both terrestrial- and handset-based technologies to deliver location information. Each technology has strengths and weaknesses. Terrestrial-based technologies allow for rudimentary location within buildings and urban canyons, while handset-based services have provided considerably more accurate location in outdoor environments. Over time, hybrids of these two underlying technologies have resulted in better, albeit not perfect, location information. As wireless phones are now the overwhelming communications tool of choice for the vast majority of U.S. citizens, ECCs are faced with volumes of calls that still remain challenged with precise location information within buildings.

After four FCC R&Os and further notices of proposed rulemakings (NPRMs), the FCC finalized the newest set of rules devised to enhance indoor location capabilities last month. The dilemma has been rather straightforward. What is technically capable, at what cost and when is it reasonably deployable? Highly accurate, oft-quoted “door to kick in” location is the ultimate goal. As one who has responded to calls, fought the fight for the initial stages of location requirements, worked actively around the country attempting to motivate ECCs to acquire the technology needed to accept location information, and managed an ECC that needed access to location technology, I am a staunch believer that we owe our public-safety partners the best location information that can be delivered.

During the past several years, APCO and NENA worked in concert with wireless carriers to improve location information. In a 2015 consensus agreement developed among APCO, NENA and the major wireless carriers, all parties agreed to work toward improvements in location information that, among other elements, included use of Wi-Fi systems within buildings. Extensive testing was conducted to show the benefits of this technology and resulted in the agreement to create the National Emergency Address Database (NEAD). Following the 2015 consensus agreement, additional improvements through the use of hybrid technologies have emerged and led to improved location of wireless users.

Additionally, parties agreed to address the underlying issue of one of the most serious deficiencies in wireless location — the floor level of a building more than a single story, commonly referred to as the Z axis. In recent years, there has been progress in the development of technologies that can address Z-axis information. While most of these newer technologies require some version of terrestrial support, general measurements can provide reasonably accurate height above some point on earth. That said, while carriers have demonstrated ever more accurate X, Y location and new technologies promise improved Z-axis (altitude) information, there is no indication that any provider in the market today can deliver which door to kick in information to the local ECC. Thus, while perfection for the public-safety community is indeed which door to kick in, a justified dose of reality has to be inserted into the debate.

APCO has consistently argued that wireless carriers should be required to translate Z-axis information into specific floors of a given building. The overlooked fact, however, is that there is no standard, much less any technology offered today that can deliver such a desire. In San Francisco, for example, a height above average terrain of 40 feet for a building on the waterfront might equate to the fourth floor, while that same elevation would equate to a third-level basement six blocks away. Similarly, two buildings across the same street would have one building listed as the 14th floor, while the other would list the 13th floor, as many buildings have no 13th floor designations.

The significant question is who is responsible for mapping the height above terrain for every building in the nation? Certainly, this data does not exist today. It has taken decades for vendors of current mapping solutions to develop accurate X, Y technology, and many ECCs expend considerable resources to develop fundamental overlays for these technologies. There has never been any expectation that wireless carriers should be responsible for developing baseline maps that are ultimately translated for use in CAD systems. It has always been ECCs’ responsibilities to use CAD software that translates X, Y information into a usable street address.

Is it reasonable to assume that wireless carriers should now be responsible for complex mapping algorithms that have traditionally been in the domain of mapping vendors or urban planning entities? Does public safety need this critical information? Absolutely yes. Did the FCC err in not making this requirement the responsibility of wireless carriers? Absolutely not.

The latest rules will require a phased-in capability on the part of wireless carriers to provide a Z, or altitude, measurement to ECCs beginning in 2021. This new standard requires Z-axis information that will provide the altitude of a wireless call in major metropolitan markets within 3 meters above or below the caller. In short, this translates to near-floor-level location in addition to the X, Y coordinate. More than 20 major public-safety associations offered support to the FCC. Standing alone, APCO has been aggressively critical of this R&O, arguing that it does not require, in simple terms, which door to kick in and has thus failed the public-safety community.

In many fields of endeavor, there is generally an ideal (perfection) that demands attention. In medicine, an ultimate goal is either the prevention of or a cure for cancer. Clearly, there is no perfection until cancer is both prevented and cured. That said, one can question whether the appropriate federal rulemaking and regulatory entities should not approve incremental steps in new drugs, procedures or testing, or should be disparaged as they do not meet the ultimate goal. The same can be said for aviation safety, highway safety or countless other critical life-safety enterprises.

One of the lessons learned since the initial R&O issued to address wireless phone location is that the commercial world, not public safety, has been a driver in improved location technologies. Uber, Grubhub, OpenTable and all similar commercial players understand the need for and demand the best possible location services. While those of us in the public safety world would like to think we drive technology, the reality is that commercial applications have, in fact, been the greatest driver of these technologies. We would all like to think that public safety is entitled to or deserves the perfect technology, but at the end of the day, it is evident that those who make money off these improved technologies are far better motivators in the development of improved technology.

The FCC has taken a commendable step in providing much-needed requirements for the location-related component of wireless calls placed to ECCs. Far short of a deficient order, the FCC has provided concrete steps for improved information to ECCs and through the release of a concurrent further NPRM, providing a path for continued improvements as future developments in technologies are realized. The rulemaking provides a vehicle for implementing the possible, not wishful thinking. In this case, the latest order addresses the good, with a look to the ultimate goal of perfection in the NPRM.

This story is part of a two-part point-counterpoint series about the FCC's 9-1-1 indoor location metric. Click here to read the other viewpoint.

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

After a 30-year career in public safety, Joe Hanna now serves as a consultant to the wireless industry in matters related to public policy and regulatory affairs. He is a fellow in the Radio Club of America (RCA), a senior fellow for the Center for Digital Government, and a life member and past president of the Association of Public-Safety Communications Officials (APCO) International. Hanna is a member of the editorial advisory board of MissionCritical Communications magazine.

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On 12/5/19, John Roberts said:
Having read Jeff Cohen's comments and the letters from Google, etc., I have to agree in whole with Joe Hanna. Over the past 40 years I've been a dispatcher, police officer and now a volunteer firefighter. I realize how critical location information is to a first responder, but I also realize that it is not the carrier's responsibility to provide it. RF location from a cell carrier by itself based on currently deployed technology is almost a joke with automatic location information (ALI) today based primarily on A-GPS from even the low-end devices. So why put the burden on carriers for something they can't even natively provide? I'm not sure the FCC should have even gotten involved in regulating this portion of the technology to begin with. The carrier is just that and should remain agnostic.

9-1-1 device location is the responsibility of the device vendor and the CAD provider receiving that location. Maybe the FCC should be mandating this for the manufacturers if they want their devices to receive FCC approval. Absent that at the moment, we still see a faster track to more robust solutions driven by the marketplace. I will point to the current 9-1-1 location clearing house, Rapid SOS, used by Apple and Google. They provide the device's enhanced location technology to public-safety answering points (PSAPs) and CAD vendors, and it's even free to any PSAP. When it comes right down to it, device location is almost entirely dependent on the best location the device itself can provide. Keep the carrier out of it, and let's develop adequate standards (3GPP etc.) that enable the accurate conveyance of that information from the call end to end. This should also include the ability of a PSAP to call that device back and poll its location information alert and countdown warning timer, a capability not currently available. These are all software solutions primarily at the device end. At our local PSAP for the past 10 years, we have incorporated 3D mapping into CAD that can take ALI information and view down to 1-meter resolution. This is an end-point mapping solution.

The accuracy of floor location will ultimately be dependent on building maps viewable at the PSAP, and this may take decades, or Google can keep building out floor plans. Otherwise let's get new laws for building owners to provide them but not anything the wireless carrier can or should provide. We actually have buildings in our municipality where the first floor may start at Floor 2 because of a 10-foot height difference from the other one it's connected to. In large cities, owners of high-rises have been known to build 15- to 20-foot high floors to cut down on taxes. The only way to solve this is a floor plan or in-place Wi-Fi or sensors the device has access to. Google suggests the device may convey this information. Fine, let it but don't burden the carrier itself with it. Get the government out of the way of innovation. Thank you Chairman Pai and put this responsibility where it belongs.
There are 21st century carrier solutions like Artemis pCell SDR RAN that can locate a device to within 1 CM with 50 times throughput, but until the industry adopts that, the carrier's hands are tied with 20th century technology.

On 12/4/19, Jeffrey Cohen said:
As disappointing as it is to see a former APCO president defending an FCC decision on 9-1-1 location accuracy that ignored what 9-1-1 center directors say they need, reasonable minds can differ. But Joe, if we're going to have a reasonable disagreement please allow me to correct a few issues in how you characterized APCO's position and what the FCC did here.

1. You said "APCO has consistently argued that wireless carriers should be required to translate Z-axis information into specific floors of a given building." That's not true. APCO repeatedly explained that the FCC inappropriately framed the issue just like you are of whether providing Z-axis information with a floor label is technically feasible. There's a difference between being able to convert a Z-axis elevation to a floor label, which requires resources that do not exist, and being able to provide Z-axis information that includes a floor label, which is possible today. By the way, Google was urging the FCC to modify the proposed rules to allow the provision of a floor label as in the label responders would see on an elevator button or stairwell door rather than mandate sole reliance on measurements of height above ellipsoid (HAE). In a letter to the FCC, Google confirmed that its process for deriving a floor label would not require converting a Z-axis altitude in terms of HAE.

2. You said "Standing alone, APCO has been aggressively critical of this R&O, arguing that it does not require in simple terms which door to kick in and has thus failed the public-safety community." That's not true for two reasons. First this was about getting the floor level, not the door to kick in. Second dozens of 9-1-1 directors were asking the FCC to require carriers to provide the floor level because the FCC's approach wouldn't work for 9-1-1. Even New York City's 9-1-1 director said they don't have the resources to make the FCC's approach work. And don't ignore FCC Commissioner Jessica Rosenworcel, a long-time supporter of 9-1-1, who was the only dissenting vote at the FCC and the only one of the commissioners to focus on the perspectives of 9-1-1 directors. You should read the commissioner's statement.

3. You say "Far short of a deficient order, the FCC has provided concrete steps for improved information to ECCs." Joe, can you even explain how the FCC will make sure carriers are complying with the Z-axis requirements? The FCC says the Z-axis rules will apply to devices that can report vertical information without a hardware upgrade, not just devices with barometric sensors. Carriers have to demonstrate the performance of a Z-axis technology in the test bed. Naturally testing would include devices that are compatible with that technology but not necessarily be representative of the devices being used in the real world. For example, if the carriers choose to deploy a Z-axis technology that is dependent upon a barometric sensing capability, the test bed would only evaluate performance of devices used by a subset of potential 9-1-1 callers whose devices are capable of delivering barometric pressure sensor-based altitude estimates. How will the carriers be able to demonstrate compliance with a commission-mandated metric that applies to 80% of all wireless calls regardless of whether the calls are from devices that have barometric sensors? Would, for example, the carriers be required to test a collection of devices that are supposedly representative of devices in circulation including some with and some without barometric pressure sensors to estimate the percentage of devices in the real world that could be covered by the carrier's choice of a Z-axis technology? Then to comply with the Z-axis metric, would carriers be required to discount the performance of their chosen Z-axis technology to account for the proportion of devices and potential 9-1-1 calls that will be covered by the technology? You're a consultant for the wireless industry. Do you really expect they'll keep adding different types of Z-axis technologies to their networks until they have a reliable estimate that real-world performance will be ±3 meters for 80% of calls? APCO raised several concerns that the FCC's Z-axis metric won't translate to real-world performance. This is just one example.

Please take a look at the blog I wrote to explain APCO's concerns: https://www.apcointl.org/fcc-on-the-verge-of-a-major-setback-to-9-1-1-location-accuracy/

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