Subject: [NEXTEL-1] In the matter of Establishment of an Interference Temperature Metric to Quantify and Manage Interference

From: [email-masked]
Date: Sun, 09 May 2004 08:57:17 -0400

Before the FEDERAL COMMUNICATIONS COMMISSION
Washington, D.C. 20554

In the matter of  Establishment of an Interference Temperature  Metric
to Quantify and Manage Interference

ET Docket No. 03-237 and to Expand Available Unlicensed Operation  in
Certain Fixed, Mobile, and Satellite
Frequency Bands

REPLY COMMENTS OF MOTOROLA, INC.

Motorola, Inc. (“Motorola”) respectfully submits these reply comments in
response to the Federal Communications Commission’s (“FCC” or
“Commission”) Notice of Inquiry and Notice of Proposed Rulemaking in the
above captioned proceeding.1 In this proceeding, the Commission’s stated
interest is in exploring options for developing a regulatory regime in
assessing interference based on the actual radiofrequency (“RF”)
environment, as opposed to being based only on transmitter operations.
The Commission therefore seeks comment on a new analytical and
regulatory model it calls the interference temperature metric.

In its opening round comments, Motorola expressed concern that
significant technical
challenges would need to be overcome before implementation of the
interference temperature
concept could be realized without threatening incumbent radio services.2
Primary among these
challenges is the need to account for a wide variety of design
characteristics of primary services

1 Establishment of an Interference Temperature Metric to Quantify and
Manage

Interference and to Expand Available Unlicensed Operation in Certain
Fixed, Mobile and Satellite Frequency Bands, Notice of Inquiry and
Notice of Proposed Rulemaking, FCC 03-289 (Nov. 28, 2003) (“NOI” or
“NPRM”).
2 Comments of Motorola, Inc., ET Docket No. 03-237, submitted April 5,
2004, at 1

(“Motorola Comments”). Unless otherwise noted, all referenced comments
can be found in ET Docket No. 03-237 and were filed on April 5, 2004.

2 without impeding the ability of those systems to evolve system designs
or technologies.3 In this regard, Motorola noted the difficulty of
measuring the noise floor in frequency bands that are actively used by
primary services and the inability of an unlicensed transmitter to
determine the path conditions between it and a potential victim receiver
operating on a primary basis.4 Motorola concluded that the technology
necessary to overcome these challenges is well beyond current state of
the art.5 Given the resulting stringent impact on the design of systems
that could be implemented under the interference temperature concept,
Motorola indicated that there is little counter balancing benefit to
pursing the concept at this time.  The overwhelming majority of parties
submitting comments in this proceeding agree with Motorola’s view.
Simply put, there is little, if any, support for application of the
interference temperature metric in any licensed band. While commenters
appreciate the Commission’s desire to explore options for improving
access to spectrum, numerous parties disagree with the fundamental
premise that the interference temperature metric is needed to replace
existing spectrum management tools. For example:

The New York State Office for Technology is concerned that the
interference
temperature represents a “revolutionary change” in the way spectrum
management is
conducted and would foster interference- limited environments at a time
when
controlling transmitter radiation and increasing receiver
sensitivity/selectivity to
enhance spectrum efficiencies would better address spectrum congestion.
6

CTIA argues that implementation of underlay spectrum rights based on the

interference temperature metric is a perpetuation of the “command and
control”
approach to spectrum management and urges the Commission to instead rely
on\

3 Id. at 2.
4 Id.
5 Id.
6 Comments of New York State Office for Technology Statewide Wireless
Network (“New
York State Comments”) at 4.

 primary users sublicensing underlay rights through secondary markets.
If underlay operations prove to be technically feasible and efficient,
primary licensees would have the economic incentive to sublease the
right to use their spectrum to such uses.7

TIA notes that imposition of an interference temperature metric will not
compensate for the absence of spectrum ma nagement that potentially
arises as a result of excessive flexibility in the Commission’s rules.
TIA believes that the current spectrum management approach of defining a
service in terms of frequency bands, transmitter power and the required
shape of the emitted spectrum, limits on out-of band and spurious
emissions provides much of the information needed by manufacturers to
design receivers responsive to market needs.

8 The Wi-Fi Alliance, comprised of companies supporting IEEE 802.11x
standards, argues that the interference temperature metric “will not be
broadly practical and applicable” and urges the Commission to “carefully
analyze the cost of a major change on transmitting systems design in
relation to the expected benefits.”9 The concerns on implementing the
interference temperature metric are in large measure predicated on the
difficulties associated with providing real time information on the
applicable spectrum environment to interference temperature controlled
devices. In its opening comments, Motorola expressed great concern that
propagation and funding issues render all of the monitoring alternatives
discussed in the NOI as problematic.10 Many commenters expressed similar
views:

The IEEE 802.11 Committee states that the cost of creating and ma
intaining a
ubiquitous network of monitoring stations would completely overwhelm any
short
term or long term benefit in new economic activity. More importantly,
the committee
notes that the complexity of the monitoring process would cast doubt on
the
reliability of the resulting data.11
7 Comments of the Cellular telecommunications & Internet Association
(“CTIA
Comments”) at 12.
8 Comments of the Telecommunications Industry Association at 6.
9 Comments of the Wi-Fi Alliance at 2, 4.
10 Motorola Comments at 13, 14.
11 Comments of IEEE 802.11 at 6.
4

Sprint’s studies conclude that two of the three monitoring approaches
discussed in the NOI are not workable at all as applied to mobile
services bands and the third approach would not be effective in mobile
services downlink (base-to- mobile) bands.12 These concerns over the
general interference temperature concept became more pronounced as
parties consider the impact on specific bands. In its comments, Motorola
stated that implementing the interference temperature in freque ncy
bands used by land mobile services is particularly challenging and not
appropriate for the foreseeable future.13 Motorola especially urged the
Commission to exempt from consideration any frequency band used by
public safety agencies.14 As reflected below, there was wide support
expressed in the comments for these positions.

New York State notes that the ability to intelligently time-share Public
Safety
spectrum with other services is not a capability that appears to be
practically
deployable without some degradation of public safety operations, either
in terms of
interference, or call blocking.15

Qualcomm shows that even a slight increase in the noise temperature in a
licensed
band would substantially impair the service provided by licensees who
have deployed
Code Division Multiple Access (CDMA) technology, resulting in a
substantially
reduced coverage area of each cell and a decreased battery life in each
wireless
phone.16

V-Comm notes that both CDMA spread-spectrum and GSM frequency hopping
systems used in today’s cellular and PCS spectrum allocations are
designed to utilize
the full set of spectrum frequencies at every cell site. While this
allows the cellular
and PCS providers to provide a highly efficient communications system
within their
limited spectrum allocations, it leaves very little or no “white space”
in the frequency,
spatial or time domains for opportunistic cognitive radio unlicensed
devices.

17
12 Sprint Corporation Comments at iii, 22-32.
13 Motorola Comments at 7.
14 Id.
15 New York State Comments at 19.
16 Comments of Qualcomm Incorporated at 9-11.
17 Comments of V-Comm LLC at 44.
5

Verizon Wireless cites technical studies that show that even seemingly
low levels of
interference would have “disastrous” consequences to CDMA customers;
reducing
coverage by as much as 32 percent in urban markets and reducing cell
site capacity
by as much as 61 percent.

18

Summarizing the concern of all CMRS carriers, CTIA concludes that
introduction of an interference temperature based system in CMRS
spectrum would have troubling effects on spectrum efficiency and service
quality while raising accountability and enforcement issues that appear
intractable.19 These comments only partially reflect the broad consensus
in the record that the Commission’s consideration of the interference
temperature metric is premature given the existing state of technology.
This view applies even more strongly to the proposals in the Notice of
Proposed Rule Making, which is considering immediate implementation of
the policy in the 6525-6700 MHz, 12.75-13.15 GHz, and 13.2125-13.25 GHz
bands. In its opening comments, Motorola stated that the Commission’s
proposals should be deferred as they rely on work conducted for the 5
GHz band that is not directly applicable to the fixed services bands
under consideration. 20 In support of this statement, Motorola submitted
a technical study that demonstrates that applying the 5 GHz parameters
to 6 GHz operations results in more than 60 dB greater interference.21
Other commenters expressed similar concerns:

The IEEE 802.11 Committee urges “caution” in moving forward in releasing
these
bands for unlicensed use as it is concerned that the interference issues
related to fixed
service operations may not have been fully examined.

22

Cingular and BellSouth recommend that the FCC should not move forward
with the
NPRM as the definition of interference temperature is not yet settled.23

18 Comments of Verizon Wireless at 11.
19 CTIA Comments at ii.
20 Motorola Comments at 15.
21 Id. at Appendix B.
22 Comments of IEEE 802.11 at 7.
23 Comments, Cingular Wireless LLC and BellSouth Corporation at 44.
6

Sprint demonstrates that transmit power control (“TPC”) and dynamic
frequency
selection (“DFS”) are technically infeasible methods for implementing
the
interference temperature concept in fixed point-to-point radio networks.

24
The United Telecommunication Council (“UTC”) urges the FCC to avoid
tests in the
6 GHz band due to fact that they are heavily used for critical
infrastructure
applications.

25

The record in this proceeding is overwhelming clear: FCC consideration
of the
interference temperature metric is premature given the technical
difficulties associated with
implementation, the potentially severe consequences on existing
services, and the limited, if any,
resulting benefits. While Motorola appreciates the Commission’s efforts
to explore new ideas
for managing the spectrum, our expectation is that more tangible
benefits will arise through the
thoughtful promotion of cognitive radios.26
Respectfully submitted,
/s/ Steve B. Sharkey
Steve B. Sharkey
Director, Spectrum and Standards Strategy
Robert D. Kubik
Manager, Spectrum and Regulatory Policy
Motorola, Inc.
1350 I Street, N.W.
Washington, D.C. 20005
(202) 371-6900
May 5, 2004
24 Sprint Corporation Comments at 38-44.
25 Comments of the United Telecom Council at 9.
26 See Comments of Motorola, Inc., ET Docket No. 03-108, submitted May
3, 2004.

http://svartifoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6516183488

--
    "NEXTEL-1 IT'S NOT JUST NEXTEL"
  Note The New address
Subscribe to Nextel-1: http://www.groups.yahoo.com/subscribe/NEXTEL-1

  "NEXTEL2 FOR iDEN SOFTWARE DEVELOPERS"
Subscribe to Nextel2: http://www.groups.yahoo.com/subscribe/NEXTEL2

  "WIRELESS FORUM HOMELAND SECURITY GROUP"
     The Complete Resource for Wireless Homeland Security.
Subscribe to WFHSG:  http://www.groups.yahoo.com/subscribe/WFHSG

------------------------ Yahoo! Groups Sponsor ---------------------~-->
Yahoo! Domains - Claim yours for only $14.70
http://us.click.yahoo.com/Z1wmxD/DREIAA/yQLSAA/61FxlB/TM
---------------------------------------------------------------------~->

-- 
    "NEXTEL-1 IT'S NOT JUST NEXTEL"
  Note The New address 
Subscribe to Nextel-1: http://www.groups.yahoo.com/subscribe/NEXTEL-1

  "NEXTEL2 FOR iDEN SOFTWARE DEVELOPERS"
Subscribe to Nextel2: http://www.groups.yahoo.com/subscribe/NEXTEL2

  "WIRELESS FORUM HOMELAND SECURITY GROUP"
     The Complete Resource for Wireless Homeland Security.
Subscribe to WFHSG:  http://www.groups.yahoo.com/subscribe/WFHSG

Yahoo! Groups Links

<*> To visit your group on the web, go to:
     http://groups.yahoo.com/group/NEXTEL-1/

<*> To unsubscribe from this group, send an email to:
     [email-masked]

<*> Your use of Yahoo! Groups is subject to:
     http://docs.yahoo.com/info/terms/