CLXXIV.Improving the Delivery of Phase II Location Information

A.Latency (Time to First Fix)

CLXXVII.A number of public safety and industry commenters support a maximum latency of 30 seconds for obtaining a location fix as reasonable based on the performance of current handset and network-based technologies.⁴ Some commenters, however, urge the Commission to set maximum latency at less than 30 seconds.⁵ Industry commenters also oppose the proposal to exclude only calls of less than 10 seconds.⁶ They argue that it is unreasonable to allow CMRS providers up to 30 seconds to obtain a location fix while also including calls lasting more than 10 but less than 30 seconds in the compliance calculation. AT&T submits that “all calls should be given at least 30 seconds for purposes of calculating the location-accuracy success rate” and that to “do [otherwise] would unfairly mischaracterize the provider’s compliance with location-accuracy benchmarks.”⁷

CLXXVIII.Discussion. We add a maximum latency requirement of 30 seconds to the existing E911 Phase II rules applicable to outdoor calls, but we conclude it is premature to include this requirement as part of the new rules adopted in this order for indoor location. Thus, for a 911 call to meet Phase II requirements, a CMRS provider must deliver Phase II-compliant information to its location information center within 30 seconds, as measured from the start of the call to when the information is delivered to the location information center. In calculating percentages of Phase II-compliant calls, CMRS providers must include calls lasting 30 seconds or more for which they are unable to deliver a Phase II location fix.⁸ We apply this requirement only to our existing E911 regime, which determines compliance based on outdoor measurements only. Thus, compliance with our TTFF requirement will be based on the results of outdoor testing, and will not be measured from the live 911 call data from the six test cities.

CLXXIX.We find that a 30-second maximum latency period appropriately balances the need for first responders to obtain a prompt location fix and the need to allow sufficient time for location accuracy technologies to work effectively.⁹ Excessive delay in the provision of location information can undermine or negate its benefits to public safety, but providing sufficient time for location technologies to work can lead to improved accuracy that reduces overall response time. As CSRIC III noted, 30 seconds is “generally accepted as the de facto standard for maximum latency in E9-1-1 location delivery.”¹⁰ The record in this proceeding similarly indicates that a maximum latency interval of 30 seconds is technically achievable using current location technology,¹¹ and that improved chipsets in devices will further reduce the frequency of calls where the TTFF takes longer than 30 seconds.¹²

CLXXX.In fact, we expect technology to reduce latency for many wireless 911 calls to significantly less than 30 seconds. CMRS providers indicate that new satellite positioning technologies they are planning to implement in conjunction with deployment of VoLTE will likely reduce latency fix for wireless 911 calls from outdoor locations.¹³ For example, newer-generation A-GNSS may be capable of generating a location fix within 12-15 seconds.¹⁴ Nevertheless, even in such cases, allowing up to 30 seconds provides additional time to refine the location information and potentially return a more accurate location fix.¹⁵ On balance, we find that a 30-second maximum latency period will encourage solutions that deliver location information to first responders quickly while providing flexibility for solutions that can deliver greater accuracy over a modestly longer time interval. Establishing a maximum latency period will also ensure that PSAPs and CMRS providers have the same expectations regarding the timeframe for delivering location information.

CLXXXI.While we adopt the 30-second maximum latency period for outdoor calls as proposed in the Third Further Notice, we decline to adopt our proposal to exclude calls of 10 seconds or less while including calls of 10 to 30 seconds in the compliance calculation. We agree with industry commenters that where a call lasts less than 30 seconds, we should not penalize the provider for failing to obtain a Phase II-compliant fix that requires up to 30 seconds to generate and that would count towards compliance if the call lasted 30 seconds or more. Therefore, we will allow CMRS providers to exclude from their compliance calculation any wireless 911 call lasting less than 30 seconds for which the provider is unable to deliver a Phase II-compliant fix. On the other hand, to provide an incentive for CMRS providers to reduce latency below 30 seconds, CMRS providers may count any Phase II-compliant call in which the location fix is delivered in less than 30 seconds, regardless of the duration of the call.

CLXXXII.Finally, as noted above, we limit the scope of the 30-second latency requirement to wireless 911 calls covered by our existing Phase II rules, as we believe it is premature to impose a latency standard for indoor calls at this time. Compliance will be measured by evaluating the results of each CMRS providers’ outdoor drive testing. CMRS providers have yet to test location for latency, among other metrics, in generating dispatchable location information derived from various indoor access points or beacons. Moreover, although location information from beacons and small cells could likely be determined almost instantaneously, the various new technologies that are included in “heightened location accuracy technologies” under the Roadmap have not yet been tested for latency. Therefore, while the record suggests that existing and developing indoor location technologies should be capable of delivering accurate location information in 30 seconds or less for most calls, we conclude that consideration of this issue should be deferred. Once there has been an opportunity to evaluate the performance of indoor location technologies based on test bed results and live call data from the six geographic test regions, we will be better able to determine whether to extend latency requirements to these new location technologies.