**FCC REPORT TO CONGRESS**

**ON THE DEPLOYMENT OF E-911 PHASE II SERVICES**

**BY TIER III SERVICE PROVIDERS**

**Submitted Pursuant to**

**Public Law No. 108-494**

**FEDERAL COMMUNICATIONS COMMISSION**

> **March 23, 2005**

[TABLE OF CONTENTS]{.underline}

[I. INTRODUCTION 1](#introduction)

[II. DEPLOYMENT OF E-911 PHASE II SERVICES BY TIER III SERVICE PROVIDERS
3](#deployment-of-e-911-phase-ii-services-by-tier-iii-service-providers)

[(1) The number of Tier III commercial mobile service providers that are
offering Phase II E-911 services.
3](#the-number-of-tier-iii-commercial-mobile-service-providers-that-are-offering-phase-ii-e-911-services.)

[(2) The number of requests for waivers from compliance with the
Commission's Phase II E-911 service requirements received by the
Commission from such Tier III providers.
3](#the-number-of-requests-for-waivers-from-compliance-with-the-commissions-phase-ii-e-911-service-requirements-received-by-the-commission-from-such-tier-iii-providers.)

[(3) The number of waivers granted or denied by the Commission to such
Tier III providers.
3](#the-number-of-waivers-granted-or-denied-by-the-commission-to-such-tier-iii-providers.)

[(4) How long each waiver request remained pending before it was granted
or denied.
4](#how-long-each-waiver-request-remained-pending-before-it-was-granted-or-denied.)

[(5) How many waiver requests are pending at the time of the filing of
the report.
4](#how-many-waiver-requests-are-pending-at-the-time-of-the-filing-of-the-report.)

[(6) When will the pending requests be granted or denied.
4](#when-will-the-pending-requests-be-granted-or-denied.)

[(7) Actions the Commission has taken to reduce the amount of time a
waiver request remains pending.
5](#actions-the-commission-has-taken-to-reduce-the-amount-of-time-a-waiver-request-remains-pending.)

[(8) The technologies that are the most effective in the deployment of
Phase II E-911 services by such Tier III providers.
5](#the-technologies-that-are-the-most-effective-in-the-deployment-of-phase-ii-e-911-services-by-such-tier-iii-providers.)

[III. CONCLUSION 7](#conclusion)

**REPORT TO CONGRESS ON THE DEPLOYMENT OF E-911 PHASE II SERVICES BY
TIER III SERVICE PROVIDERS**

On December 23, 2004, Congress directed the Commission to submit a
report to the Committee on Energy and Commerce of the House of
Representatives and the Committee on Commerce, Science, and
Transportation of the Senate on information related to the deployment of
enhanced 911 (E-911) Phase II services by Tier III service
providers.[^1] In response, we report on the status of E-911 deployment
by Tier III carriers,[^2] as well as the disposition of requests for
waiver of the Commission's E-911 rules filed by Tier III carriers. We
also address the technologies available for Tier III carriers to provide
E-911 Phase II location information as required by our rules.

# INTRODUCTION

The Commission first crafted rules in 1996 to ensure that location
information for wireless 911 callers would be provided to 911 call
centers, or Public Safety Answering Points (PSAPs).[^3] The Commission's
requirements to provide location information, a capability referred to
as Automatic Location Identification (ALI), are comprised of two phases.
Pursuant to the Phase I rules, wireless carriers were required to
provide a callback number for the handset placing the 911 call and
report the location of the cell tower that received the call. The Phase
I rules required compliance by April 1, 1998, or within six months of a
PSAP request, whichever is later.[^4] Under the Phase II rules, Tier III
wireless carriers were required to provide more accurate 911 call
location information, beginning September 1, 2003, or within six months
of a PSAP request, whichever is later.[^5] The degree of location
accuracy required under the Phase II rules varies, depending on whether
the carrier utilizes a network-based or handset-based solution.[^6]

The Commission is committed to ensuring that the Nation's wireless
telephone users have timely access to emergency services using E-911
technology. In adopting the E-911 rules, however, the Commission
recognized that there could be circumstances where deployment of
wireless E-911 service might not be technically or economically feasible
within the scheduled time periods, and anticipated that it would grant
relief in cases where carriers filed waiver requests that met the
Commission's standards for waiver relief.[^7] Many Tier III carriers
have filed requests for waivers or extensions of the Commission's E-911
Phase II deadlines. In making determinations to grant or deny relief,
the Commission has balanced its policy objective of ensuring that E-911
Phase II service is deployed as quickly as possible with the financial
and technical challenges faced by certain carriers.[^8]

# DEPLOYMENT OF E-911 PHASE II SERVICES BY TIER III SERVICE PROVIDERS

We provide below the specific information requested by Congress in
section 106 of the ENHANCE 911 Act. A detailed listing of each Tier III
service provider, its filings, and dates of Commission action, is
attached as Appendix A.

## The number of Tier III commercial mobile service providers that are offering Phase II E-911 services.

Based on their most recent filings or reports to the Commission and
publicly available information, out of the approximately 390 Tier III
licensees,[^9] ten currently are providing Phase II service to at least
one PSAP.[^10] Six of these service providers provide Phase II service
through a handset-based solution, and four through a network-based
solution.

## The number of requests for waivers from compliance with the Commission's Phase II E-911 service requirements received by the Commission from such Tier III providers.

Over the course of the last nine years, 184 requests for waiver relief
from the Commission's E-911 rules have been filed.[^11]

## The number of waivers granted or denied by the Commission to such Tier III providers.

As detailed below, the Commission has addressed a total of 184 requests
for relief. Of these, the Commission granted 175 requests, in whole or
in part, and denied or dismissed nine requests.

a.  Prior to the July 2002 *Non-Nationwide Carriers Order*, ninety-nine
    requests for waiver were filed. In the *Non-Nationwide Carriers
    Order*, released July 26, 2002, the Commission granted these
    ninety-nine requests a temporary stay of the Phase II service
    requirements.[^12]

b.  On November 20, 2002, the Tier III Coalition filed a joint request
    for relief on behalf of twelve service providers, requesting limited
    forbearance from the Phase II accuracy requirements. In an order
    released on November 19, 2003, the Commission denied the request for
    relief.[^13]

c.  Between September 2002 and September 2003, forty-four requests for
    relief were filed requesting the same relief granted in the
    *Non-Nationwide Carriers Order*. In its October 10, 2003 *Order to
    Stay,* the Commission granted those requests for relief.[^14]

d.  On March 22, 2005, the Commission adopted an order granting, in
    whole or in part, thirty-two requests for relief. The Commission
    denied or dismissed eight other requests for relief.

## How long each waiver request remained pending before it was granted or denied.

As Appendix A shows, the requests for relief addressed in the
*Non-Nationwide Carriers Order* remained pending an average of 255 days;
those decided in the *Order to Stay* remained pending an average of 137
days. The request for relief filed by the Tier III Coalition addressed
in the *Forbearance Order* remained pending for 363 days. The requests
for relief addressed in the *2005 Tier III Order* remained pending an
average of 461 days. The average number of days that all Tier III
requests for relief addressed by the Commission remained pending is 275.
The Commission measured the amount of time any request for relief
remained pending based on the date of initial filing. However, in many
cases, petitioners subsequently amended their initial waiver requests on
one or more occasions in order to modify the relief sought and/or report
on changed circumstances.

## How many waiver requests are pending at the time of the filing of the report.

There are no waiver requests pending as of the filing of this
report.[^15]

## When will the pending requests be granted or denied.

As noted above, there are no waiver requests pending as of the filing of
this report, and thus this item is not applicable.

## Actions the Commission has taken to reduce the amount of time a waiver request remains pending.

The Commission recently has taken the following actions to reduce the
processing time for waiver requests:

-   Established an E-911 Task Force of attorneys, engineers and support
    staff dedicated to expeditious review of E-911 waiver requests.

-   Created a database for tracking E-911 specific matters.

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-   Trained staff to streamline the processing of waiver requests.

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-   Hired additional management staff to directly oversee E-911 matters.

-   Established speed-of-disposal objectives for requests for waiver
    relief.

-   Initiated periodic meetings with handset and other equipment
    manufacturers to inform FCC staff of the technical, cost and other
    factors that influence disposition of waiver requests.

-   Encouraged carriers to consult with the Commission in advance of
    filing waiver requests to ensure that the waiver proponent is aware
    of the need for factual documentation of claims and of the
    Commission's standards for evaluation of waiver requests.

## The technologies that are the most effective in the deployment of Phase II E-911 services by such Tier III providers.

**Introduction**

In considering the technologies that are most effective in the
deployment of Phase II E-911 services by Tier III carriers, it is
important to recognize that such providers, in general, serve rural
markets across the U.S. In choosing among available Phase II E-911
technologies, a carrier's decision reasonably will be affected by such
factors such as its air interface,[^16] its available infrastructure
(*e.g*., number and location of base stations deployed), and the
environmental characteristics of its service area, such as population
density and terrain.

In the sections below, we provide an overview of the various solutions
that are available to Tier III carriers. We describe how these solutions
relate to the particular air interface being employed, and some of the
constraints that carriers may encounter.

**Solutions For Phase II E-911**

As an initial matter, it is important to note that a wireless carrier's
E-911 system generally consists of two interconnected segments: the air
interface and the fixed, backhaul network[^17] over which E-911 voice
calls are routed. Regardless of the particular air interface a carrier
chooses to employ, the basic structure of the backhaul network is
generally the same. Therefore, we will concentrate on the possible
solutions for obtaining and transmitting location information over the
air interface to ensure the successful provision of Phase II E-911
services.

Carriers have several choices for the air interface they choose to
employ. In the United States, the most common air interfaces are Code
Division Multiple Access (CDMA),[^18] Time Division Multiple Access
(TDMA),[^19] Global System for Mobile Communications (GSM),[^20]
Integrated Dispatch Enhanced Network (iDEN),[^21] and the original
analog Advanced Mobile Phone Service (AMPS),[^22] the use of which is
rapidly declining. The choice among these specific air interfaces
affects the choice of solution for Phase II E-911 deployment.

Carriers have three methods for implementing E-911 solutions:
network-based, handset-based and hybrid methods that involve both
network-based and handset based aspects. The implementation of a
network-based solution involves upgrading network components to obtain
information about the location of a handset. Network-based solutions can
be accomplished by independently overlaying a network over the existing
wireless network, by integrating technology into existing base stations,
or by a combination of both steps. Network solutions can be used with
any handset because the location is determined by information gathered
at the base station receivers. Handset-based solutions require that each
handset be equipped with circuitry capable of independently determining
the location of the caller and passing this information to a mobile
location center for processing. Handset-based solutions require minimal,
if any, network upgrades because the location data is determined by the
handset and that information can be relayed to the PSAP. Hybrid
solutions require modifications to the network and handsets equipped
with location-determining circuitry, and determine location based on
information gleaned from both elements.

There are a number of technologies available for determining a caller's
location after initiating a 911 call from a mobile handset, but the
state of their development differs:[^23]

-   Network Solutions

    -   Angle of Arrival (AOA)[^24]

    -   Uplink Time Difference of Arrival (U-TDOA)[^25]

    -   Wireless Location Signatures[^26]

        -   Location Pattern Matching (LPM)

        -   Multi-path Fingerprinting (MP)

    -   Enhanced Cell Identity (E-CID)[^27]

-   Handset Solutions

    -   GPS[^28]

-   Hybrid Solutions

    -   Assisted GPS (A-GPS)[^29]

        -   Wireless Assisted GPS[^30]

        -   TV-GPS[^31]

    -   Advanced Forward Link Trilateration (A-FLT)[^32]

    -   Timing Advance/Network Measurement Report (TA/NMR)[^33]

    -   Enhanced Observed Time Difference (E-OTD)[^34]

**Network based Solutions**

Network based E-911 location systems employ specialized equipment
capable of capturing signals from a mobile unit that initiates a 911
call and use the signal attributes to determine the mobile location.
Ideally, this equipment is located at existing base stations so that the
existing antennas and RF circuitry can be used, thus minimizing
deployment cost. However, in some cases, new receive-only sites must be
used to provide the required degree of location accuracy.[^35]

The primary advantage of network based solutions for E-911 is that they
can work with any handset regardless of type or age. This is because all
the processing to determine mobile location is done by the network using
properties of the received mobile signal. Thus, network solutions allow
more rapid Phase II implementation. But network based solutions do
require modification of a carrier's network sites. However, cost and
accuracy of the various techniques employed for network E-911 solutions
can differ substantially. Generally, network solutions tend to be less
accurate than handset based solutions. Depending on the technology and
the implementation, the accuracy of network solutions may only approach
certainty within approximately 30 meters under ideal circumstances.

**Handset based Solutions**

Handset techniques rely on the use of a handset that includes
specialized chipsets capable of calculating its own position.
Accordingly, handset solutions generally take more time to deploy than
network based solutions because most customers must be supplied with new
handsets. However, handset-based solutions generally do not require the
network upgrades, including sophisticated processing capabilities,
inherent with network based solutions. The location uncertainty for a
GPS handset operating with clear view of the GPS satellite constellation
can be very small (easily less than 10 meters). However, in less ideal
operating circumstances, the GPS handset may have significant problems
providing accurate location information. As with network solutions,
handset solutions, and the combination of either solution with air
interface measurement characteristics, have varying degrees of cost and
accuracy.

**Hybrid Solutions**

Hybrid solutions obtain location by collecting measurement information
from both the wireless network and the handset. They provide flexibility
to allow the location derivation to be built on a variety of
configurations where measurements can be performed at the handset, or
the base station, or both. The leading hybrid solution is A-GPS. This
technology uses carrier network signals to supplement and enhance the
standard handset based GPS information and improves both the location
accuracy and the areas of coverage normally available to the standard
GPS device. It enables location determinations to be made under
conditions that normally impair reception of the satellite signals such
as urban canyons, and inside structures such as buildings or parking
garages, or where the GPS signal is affected by multipath fading. Hybrid
solutions can be more robust than either the network or handset
solutions alone, since they provide a redundant location capability that
can accommodate equipment outages or standard system repair and
reconfiguration. Hybrid technologies such as A-GPS also provide very
small location uncertainties but over much broader coverage conditions
than the standard handset solution.

**E-911 Solutions for Tier III Carriers**

The Commission recognized that various technical approaches have their
respective advantages and disadvantages and that competitive development
of different approaches was most likely to lead to the provision of
accurate Phase II location information to PSAPs, and, accordingly, did
not mandate the use of any particular technical approach. Instead, the
Commission found that, so long as they meet particular accuracy and
performance requirements, any of these approaches will further the
public interest.[^36] Depending on the technology employed, the carrier
must identify the location of the caller within certain accuracy and
reliability standards. In recognition of the fact that handset based
technologies generally require a longer phase-in period, the Commission
established a tighter accuracy standard for handset based
solutions.[^37]

The Commission recognized that each type of solution has certain
characteristics that are particularly relevant for Tier III carriers in
rural areas.[^38] For example, network-based solutions may not be
feasible in many rural wireless networks because the topography of such
networks often does not permit sufficient triangulation. Because base
stations in many rural areas are located along highways, they often do
not have much geometric diversity, which hampers the ability to
triangulate a signal to obtain a location.[^39] Similarly, wireless
location signature techniques that rely on signal reflections are not as
well suited to rural areas, as compared to urban environments, because
rural locations do not have many obstacles to create these reflections.
However, handset based solutions often are well-suited to rural areas
because GPS satellites usually will be easily visible by a handset, that
is, not obstructed by tall buildings.[^40] Network based solutions AOA
and TDOA, which rely on direct line of sight from the handset to the
base station, are likely to be better network based choices for Tier III
carriers than location signature techniques that rely on reflections.
Furthermore, there are difficulties with using network based
technologies for the CDMA air interface, because CDMA does not readily
permit signals to be easily received or monitored at more than one base
station, a requirement for most network based solutions.[^41] A
disadvantage of handset based solutions is that they require the
replacement or upgrading of handsets already in use.[^42]

In selecting a location technology, another key element for Tier III
carriers is the relative state of development of the various technical
solutions for their particular air interface. In many instances, the
selection of technical solutions by the nationwide (Tier I) carriers,
with whom the Tier III carriers both share air interfaces and have
roaming agreements, has driven the development and deployment, and thus
the availability, of particular technical solutions.[^43] Generally,
CDMA and iDEN carriers deploy an A-GPS handset based location
technology, in some cases supplemented by A-FLT. The two largest Tier I
CDMA carriers, Sprint and Verizon Wireless, use A-GPS. The nationwide
TDMA and GSM carriers deploy network based location technologies, such
as TDOA, etc. Cingular and T-Mobile use the TDOA network based location
technology. The technology chosen by the major carriers can be
particularly important for Tier III carriers because the resources
required to implement an E-911 system can be substantial and each
technology choice and speed of implementation presents its own resource
challenge. Rural carriers thus may often leverage the extensive resource
investments by the major carriers, and need not expend time and
resources in investigating the performance of the universe of location
technology choices.

**Summary**

As explained above, there are many technologies that have the capability
of providing Phase II E-911 location information -- each with its
respective advantages and disadvantages. The Commission has not mandated
the use of any particular technical approach, but has established
accuracy and performance measures so that any approach implemented must
further the public interest. Within the public policy parameters set by
the Commission, the best choice for Tier III carriers -- as described
above -- will depend on these factors. In the end, there is no one
solution that is necessarily better than another. Each Tier III carrier
must assess its own situation in terms of geography, technology,
economics, and ease of implementation to determine which solution for
Phase II E-911 best complies with the Commission's Phase II accuracy
requirements.

# CONCLUSION

The Commission is firmly dedicated to ensuring the widespread and rapid
deployment of wireless E911 services and, as this report demonstrates,
is committed to working closely with Tier III carriers to balance this
important public policy objective with the unique needs and individual
challenges faced by small wireless carriers. Further, consistent with
the requirements of the ENHANCE 911 Act, the Commission is taking steps
to ensure that it responds swiftly to requests for relief filed by Tier
III carriers. The Commission is pleased to have provided the above
report and will continue its ongoing efforts to foster the deployment of
Phase II E911 service by Tier III carriers.

[^1]: National Telecommunications and Information Administration
    Organization Act -- Amendment, Pub. L. 108-494, § 106, 118 Stat.
    3986, 3991 (2004) (ENHANCE 911 Act). Specifically, Section 106 of
    the ENHANCE 911 Act required the Commission to submit a report to
    Congress no later than March 23, 2005. Section 106 states:

    SEC. 106. REPORT ON THE DEPLOYMENT OF E-911 PHASE II SERVICES BY
    TIER III SERVICE PROVIDERS.

    Within 90 days after the date of enactment of this Act, the Federal
    Communications Commission shall submit a report to the Committee on
    Energy and Commerce of the House of Representatives and the
    Committee on Commerce, Science, and Transportation of the Senate
    detailing\--

    \(1\) the number of tier III commercial mobile service providers
    that are offering phase II E-911 services;

    \(2\) the number of requests for waivers from compliance with the
    Commission\'s phase II E-911 service requirements received by the
    Commission from such tier III providers;

    \(3\) the number of waivers granted or denied by the Commission to
    such tier III providers;

    \(4\) how long each waiver request remained pending before it was
    granted or denied;

    \(5\) how many waiver requests are pending at the time of the filing
    of the report;

    \(6\) when the pending requests will be granted or denied;

    \(7\) actions the Commission has taken to reduce the amount of time
    a waiver request remains pending; and

    \(8\) the technologies that are the most effective in the deployment
    of phase II E-911 services by such tier III providers.

[^2]: The Commission defines Tier III service providers as
    non-nationwide Commercial Mobile Radio Service (CMRS) providers with
    no more than 500,000 subscribers as of the end of 2001. *See*
    Revision of the Commission's Rules to Ensure Compatibility with
    Enhanced 911 Emergency Calling Systems, Phase II Compliance
    Deadlines for Non-Nationwide Carriers, CC Docket No. 94-102, *Order
    to Stay*, 17 FCC Rcd 14841, 14848 ¶ 22 (2002) (*Non-Nationwide
    Carriers Order*).

[^3]: *See* Revision of the Commission's Rules to Ensure Compatibility
    with Enhanced 911 Emergency Calling Systems, CC Docket No. 94-102,
    *Report and Order and Further Notice of Proposed Rulemaking*, 11 FCC
    Rcd 18676 (1996) (*E-911 Report and Order*).

[^4]: *See* 47 C.F.R. § 20.18(d).

[^5]: *See* *Non-Nationwide Carriers Order*, 17 FCC Rcd at 14852-53 ¶¶
    32-33.

[^6]: *See* 47 C.F.R. § 20.18(h). Specifically, the standards for Phase
    II location accuracy and reliability are as follows: (1) for
    network-based technologies, 100 meters for 67 percent of calls, and
    300 meters for 95 percent of calls, and (2) for handset-based
    technologies, 50 meters for 67 percent of calls, and 150 meters for
    95 percent of calls. Network-based location solutions employ
    equipment and/or software added to wireless carrier networks to
    calculate and report the location of handsets dialing 911. These
    solutions do not require changes or special hardware or software in
    wireless handsets. *See* 47 C.F.R. § 20.3(c), *Network-based
    Location Technology*. Handset-based location solutions employ
    special location-determining hardware and/or software in wireless
    handsets, often in addition to network upgrades, to identify and
    report the location of handsets calling 911. *See* 47 C.F.R. §
    20.3(c), *Location-Capable Handsets.* Hybrid solutions combine
    network-based equipment with handset-based location technologies,
    and must meet the handset-based accuracy requirements. 

[^7]: *See E-911 Report and Order*, 11 FCC Rcd at 18718 ¶ 84.

[^8]: *See Non-Nationwide Carriers Order* (granting a temporary stay of
    the Phase II deployment deadlines); Revision of the Commission's
    Rules to Ensure Compatibility with Enhanced 911 Emergency Calling
    Systems, CC Docket No. 94-102, *Order to Stay*, 18 FCC Rcd 20987
    (2003) (*Order to Stay*)(describing the criteria necessary for
    obtaining waivers); Revision of the Commission's Rules to Ensure
    Compatibility with Enhanced 911 Emergency Calling Systems, E-911
    Phase II Compliance Deadlines for Tier III Carriers, CC Docket No.
    94-102, *Order*, FCC 05-79 (adopted Mar. 22, 2005)(*2005 Tier III
    Order*)(addressing numerous requests for waiver of the Phase II
    service rules).

[^9]: This number is an approximation, based on the best data available
    to the Commission. The most recent opportunity the FCC had to
    identify the universe of Tier III carriers was in October 2000, when
    it required all Tier III carriers to file status reports. At that
    time, 390 Tier III carriers responded. However, the Commission
    believes this number has been affected by subsequent mergers,
    acquisitions and changed business plans.

[^10]: These carriers, including the states within which they are
    providing Phase II service, are: Amarillo License, L.P. (Texas);
    Cellular South Licenses, Inc. (Mississippi, Tennessee, Alabama, and
    Florida); Corr Wireless Communications, LLC (Alabama); High Plains
    Wireless, L.P. (Texas); Iowa Wireless (Iowa); North Carolina RSA 1
    d/b/a Ramcell of North Carolina; North Carolina RSA 3 Cellular
    Telephone Company d/b/a Carolina West Wireless; N.E. Colorado
    Cellular, Inc.; South Canaan Cellular Communications Company LP
    (Pennsylvania); and Southern Illinois RSA Partnership d/b/a First
    Cellular of Southern Illinois. In addition, Edge Wireless provides a
    limited form of Phase II service to four Oregon counties using
    handsets with a special battery with built-in GPS capability.
    Because the Commission does not require regular Phase II status
    reports from Tier III carriers, some carriers may have begun
    providing Phase II service without notifying the Commission, or
    since their most recent filings.

[^11]: Certain requests for relief of the Phase II requirements were
    filed on behalf of more than one Tier III carrier. Furthermore,
    while not covered by the requirements of Section 106 of the ENHANCE
    911 Act, we note that one petition for forbearance relating to the
    requirements of Section 20.18(g) of our rules remains pending as of
    the filing of this report.  The Tier IV Coalition filed
    this petition on December 28, 2004, pursuant to Section 10 of the
    Communications Act, 47 U.S.C. § 160.

[^12]: *See* *Non-Nationwide Carriers Order*, 17 FCC Rcd at 14852-53 ¶¶
    32-33.

[^13]: *See* Petition for Forbearance From E-911 Accuracy Standards
    Imposed on Tier III Carriers for Location Wireless Subscribers Under
    Rule 20.18(h), WT Docket No. 02-377, *Order*, 18 FCC Rcd 24648
    (2003) (*Forbearance Order*).

[^14]: *See Order to Stay*, 18 FCC Rcd at 20998-99 ¶ 31.

[^15]: While not covered by the requirements of Section 106 of the
    ENHANCE 911 Act, we note that one petition for forbearance relating
    to the requirements of Section 20.18(g) of our rules remains pending
    as of the filing of this report.  The Tier IV Coalition filed
    this petition on December 28, 2004, pursuant to Section 10 of the
    Communications Act, 47 U.S.C. § 160.

[^16]: In wireless communication systems, the air interface is the
    radio-frequency portion of the circuit between the handset and the
    active base station.

[^17]: A "backhaul network" is the microwave link, fiber, or other
    wireline connection between individual cell sites and the switch
    that controls routing of calls.

[^18]: Code Division Multiple Access is a digital air interface for
    wireless systems that uses spread spectrum techniques. In a CDMA
    system, each user uses the full available spectrum, but individual
    calls are assigned a unique code used to differentiate them. The
    early version of the CDMA protocol is called IS-95 and uses a
    bandwidth of 1.25 MHz. A newer, improved version called CDMA-2000 in
    the U.S. (and WCDMA in Europe) uses bandwidths of 1.25 MHz or more
    and achieves much higher subscriber capacity than earlier versions.

[^19]: Time Division Multiple Access is a digital air interface for
    wireless systems that divides each wireless channel into discrete
    time slots in order to increase the number of calls that can be
    carried in a given bandwidth. Individual users are assigned a time
    slot in a particular channel on which to communicate. Today, the
    TDMA standard commonly known in North America is IS‑136.

[^20]: The Global System for Mobile Communications is a digital air
    interface for wireless systems that uses TDMA techniques to divide
    each channel into eight discrete time slots allowing for up to eight
    simultaneous calls using the same frequency.

[^21]: iDEN is a proprietary TDMA-based digital wireless air interface
    standard designed by Motorola for use on Specialized Mobile Radio
    (SMR) networks.

[^22]: AMPS is the original analog wireless air interface standard used
    in cellular systems in the U.S.

[^23]: Because many E-911 solutions exist or are proposed and many
    continue to be developed, this is not a comprehensive list, but a
    list of the most common or well-known.

[^24]: Angle of Arrival technology measures the direction of arrival of
    the caller's signal (generally at least three measurements are
    needed) at different cell sites. Each cell site receiver sends this
    direction information to the mobile switch where the angles are
    compared and the latitude and longitude of the caller is computed
    and sent to the PSAP. AOA works with any handset -- digital, analog,
    TDMA, GSM, CDMA, etc.

[^25]: This is sometimes referred to simply as Time Difference of
    Arrival (TDOA). Time Difference of Arrival relies on the fact that
    each cell site is generally a different distance from the caller and
    that signals travel with constant velocity. Therefore, each signal
    arrives at the cell site at slightly different times. Using these
    properties, a signal defines a locus of points on a circle around a
    base station on which a mobile could be located. Then, using
    synchronized receivers, the times can be compared and a latitude and
    longitude can be computed and sent to the PSAP. At least three
    different receivers are needed for TDOA to work. TDOA works with any
    handset -- digital, analog, TDMA, GSM, CDMA, etc.

[^26]: Wireless Location Signature methods compare the radio signal
    received to a database of standard signal characteristics, such as
    reflections and echoes. Using this information from several cell
    site receivers, the caller location can be computed and sent to the
    PSAP. This technique works best in urban environments where lots of
    structures exist to provide the needed reflections. LPM works with
    any phone -- digital, analog, TDMA, GSM, CDMA, etc.

[^27]: Enhanced Cell Identity uses a combination of angular information
    (the cell sector receiving the signal) and timing information to
    approximate the location of the handset.

[^28]: GPS techniques use handsets equipped with GPS receivers. The GPS
    receiver determines the caller's latitude and longitude which is
    sent to the provider's receivers and relayed to the PSAP.

[^29]: Assisted GPS uses techniques and advanced chipsets designed to
    allow reception of GPS signals indoors. Assisted GPS can be
    supplemented with an advanced forward link trilateration (A-FLT)
    system. A-FLT is a network-based location technology that takes
    measurements of signals from nearby base stations and reports time
    and distance readings back to the network, which uses them to
    triangulate an approximate location of the handset.

[^30]: Wireless Assisted GPS generally uses advanced chipsets capable of
    acquiring very weak GPS signals and integrating the signals very
    quickly to determine location.

[^31]: TV-GPS uses synchronization signals from television stations to
    determine handset location when indoors. Because of the frequency
    and power of TV signals, they often can be received at indoor
    locations where GPS signals cannot.

[^32]: Advanced Forward Link Trilateration is a handset-based position
    location technology that works by using measurements, taken by the
    handset, of signals from nearby base stations, and reporting the
    time/distance readings back to the network, which are then used to
    triangulate an approximate location of the handset. In general, at
    least three surrounding base stations are required to obtain an
    optimal position fix.

[^33]: This method relies in part on timing advance, which is the
    maximum amount of time that a TDMA mobile station uses to compensate
    for propagation delay in order to avoid user time slot overlap when
    the mobile is far away from the base station. It also employs
    information from the Network Management Report, which is the
    measurement done either at the handset or base stations to improve
    communication flow on the air interface. Various events -- such as
    handoff, power control, and candidates list -- use the Network
    Management Report.

[^34]: Enhanced Observed Time Difference measures the differences in
    time that signals from the base stations take to reach both the
    handset and a fixed point in the network. This information is then
    sent from the handset and the fixed point to a mobile location
    center where a latitude and longitude are computed and sent to the
    PSAP.

[^35]: Network based solutions generally rely on triangulation
    techniques which provide more accurate location estimates as the
    number of sites used and their location diversity increases. Because
    rural areas generally have a low density of base stations it may be
    necessary to install some receive-only sites to ensure the ability
    to determine handset location.

[^36]: *See* Revision of the Commission's Rules to Ensure Compatibility
    with Enhanced 911 Emergency Calling Systems, CC Docket No. 94-102,
    *Third Report and Order*, 14 FCC Rcd 17388, 17395, 17404-05 ¶¶ 14,
    32-33 (1999) (*Third R&O*). The Commission continues to allow any
    location technology to be used that can comply with specified
    accuracy, reliability, and deployment schedule requirements. *See*
    *Non-Nationwide Carriers Order*, 17 FCC Rcd at 14841-42 ¶ 2 (2002).

[^37]: *See* *Third R&O*, 14 FCC Rcd at 17392 ¶ 9. *See also supra* note
    6.

[^38]: *See* *Third R&O*, 14 FCC Rcd at 17391 ¶ 6.

[^39]: *See* *id*. at 17391, 17400 ¶¶ 6, 23.

[^40]: *See id.* at 17400 ¶ 24.

[^41]: *See* *id*. at 17402 ¶ 26.

[^42]: *See* *id*. at 17404 ¶ 31. Additionally, Tier III carriers that
    have selected a handset-based solution have had to upgrade their
    networks to a new air interface such as CDMA or GSM. *See* *2005
    Tier III Order* at §§ III. A, D, and E.

[^43]: The Commission has found that handset vendors and network-based
    location technology vendors give priority to the larger, nationwide
    carriers, whose deployment schedules have created downstream delays.
    *See Non-Nationwide Carriers Order*, 17 FCC Rcd at 14844 ¶ 11.