COMMONWEALTH of VIRGINIA
DEPARTMENT OF TRANSPORTATION
1401 EAST BROAD STREET
RICHMOND, VIRGINIA 232192000
Gregory A. Whirley
Commissioner
December 3,2010
Office of the Secretary
Federal Communications Commission
445 12th St., SW, Room TWA325,
Washington, DC 20554
RE: Comments on the Technical and Operational Feasibility of Enabling Flexible Use of the
700 MHz Public Safety Narrowband Allocation and Guard Band for Broadband Services
PS Docket No. 06-229
Dear Sir or Madam:
This letter is in response to the Federal Communications Commission's (FCC) Public Notice
requesting comments on the Technical and Operational Feasibility of Enabling Flexible Use of
the 700 MHz Public Safety Narrowband Allocation and Guard Band for Broadband Services (PS
Docket No. 06-229). The Virginia Department of Transportation (VDOT) respectfully submits
the following general comments, as well as responses to the questions presented by FCC.
Overall, VDOT is concerned with the proposed redesignation of the 700 MHz narrowband
(voice) channels to allow broadband use. Comingling of broadband technology and modes
within a band of frequencies designated and already in use for narrowband will likely cause
interference to existing emergency response radio systems. VDOT respectfully suggests that the
creation of a robust public safety broadband spectrum by pairing the additional unsold 10 MHz
"D Block" with 10 MHz of adjacent public safety spectrum already designated for broadband
provides a more feasible alternative to the proposed redesignation.
What is the current and anticipated use of 700 MHz narrowband networks?
VDOT's current use of 700 MHz narrowband networks includes portable and vehicle repeater
components of the Virginia State Agencies Radio System in every part of the state.
VirginiaDOT.org
WE KEEP VIRGINIA MOVING
Federal Communications Commission
December 3,2010
Page Two
Would the flexibility to offer broadband services in all or a portion of the 700 MHz
narrowband spectrum and/or the guard band promote more efficient use of 700 MHz
public safety spectrum? Are there efficiency gains that could be realized by enabling this
flexibility? For example, could the use of the narrowband spectrum help satisfy needs for
increased broadband capacity? Or could broadband spectrum help satisfy the needs for
narrowband capacity over time? What would need to happen for this to occur?
From the VDOT perspective, any efficiency gains achieved through greater flexibility within the
broadband spectrum would be offset by the interference risks to existing response systems.
There is no known evidence that would suggest these risks could be mitigated sufficiently to
safeguard the progress in establishing reliable and interoperable channel assignments by state
and regional committees over recent years.
If the Commission were to allow flexible use of 700 MHz narrowband spectrum and/or the
guard band, would broadband operations in this spectrum potentially interfere with
existing or future public safety narrowband operations? We specifically seek technical
information on the likely extent of such interference scenarios. What steps could be taken
to mitigate such potential harm?
Comingling of broadband technology and modes within a band of frequencies designated and
already in use for narrowband will likely cause interference to existing emergency response radio
systems. State and regional planning committees have worked over a number of years to
establish well organized and coordinated channel usage. This cooperation and coordination
could be jeopardized by the FCC's proposal, as broadband encroachment may disrupt already
established channel assignments and create interference.
What impact would allowing flexible use of all or a portion of narrowband spectrum have
on the continued ability to support nationwide narrowband interoperability?
Allowing broadband to overlay and dislodge the 700 MHz narrowband channels may likely
negate the intense work that created the designated nationwide interoperability channels. This
was one of the main selling points during the creation of the public safety portion of the 700
MHz band. Broadband overlaid on narrowband channels will disrupt the nationwide
standardization that was diligently sought and created.
How much, if any, of the narrowband allocation and guard band should be made available
for broadband operations? Should some portion of this spectrum (e.g., the upper portion of
the band furthest from the existing public safety broadband spectrum) continue to be
reserved exclusively for narrowband operations?
Federal Communications Commission
December 3, 2010
Page Three
No portion of long standing narrowband channels should be made available for broadband use.
The 10 MHz of Block D sits adjacent to the public safety broadband channels and that spectrum
is needed to create a robust, standardized and national public safety broadband network.
If flexibility in the narrowband spectrum were allowed, what role should the 700 MHz
RPCs and the states play in its implementation?
The primary purpose of cooperation among states and RPCs was to establish well coordinated
and standardized implementation of the 700 MHz band. Any process that circumvents the RPCs
or minimizes their role would create the same channel interference experienced in the lower
bands.
What would be the impact of allowing flexibility on the development of broadband,
narrowband, and dual-use equipment in the 700 MHz public safety spectrum? If the
Commission were to permit flexible use of the narrowband spectrum, what if any impact
should this have on the existing rules that require 700 MHz narrowband systems to
narrowband to 6.25 kHz bandwidth channels by December 31, 2016? Should the
Commission reconsider this requirement? Would public safety resources be better spent
transitioning 700 MHz narrowband operations onto a broadband platform?
As mentioned earlier, the principal concern of the Department is the risk of decreased
interoperability posed by potential interference of comingled technologies and modes. A holistic
review of the 700 MHz public spectrum should also include consideration ofpairing the
additional unsold 10 MHz "D Block" with 10 MHz of adjacent public safety spectrum already
designated for broadband.
VDOT appreciates the opportunity comment on the proposed redesignation. If you have any
questions, you may to contact Bill Brown, Radio Manager, at 804-692-2520.
Sincerely,
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Gregory A. Whirle~ -, I