LEIRP ou Le PFD

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Title: LEIRP ou Le PFD

1
LEIRPouLe PFD?
Consulting on wireless technology and policy

ANFR 26 avril 2006
2
Background

Many concepts of spectrum regulation date to the
early days of radio technology
Higher frequencies and new technology may create
new options
Traditionally ERP and EIRP have been the
dimension space to specify transmitter power

3
Basic Spectrum Management Issues

Cochannel issues are the most straightforward and
have a major impact on frequency reuse
Adjacent and nearby channels also have a real
impact due to limitations of practical receivers
Example In US NTSC/TV rules only 1 of 6 channels
used in a given city due to receiver limitations

4
Basic Spectrum Management Issues

F1 transmitter
F2 receiver
F2 transmitter
5
Northpoint Nextel

Two recent FCC issues with near/far at their
roots
Northpoint
A proposal to use 12 GHz BSS downlink band for
terrestrial point-to-multipoint video
distribution
If transmitter on north side of community, no
interference on a clear day
Rain impacts downlink more than terrestrial path
and leads to near/far problems

6
Northpoint Nextel

Nextel operated mobile telephone system in 800
MHz spectrum interleaved with land mobile public
safety/PS users - for historical reasons
Near/far interference near Nextel towers results
in receiver-generated intermodulation in PS
receivers

7
csc2 Antenna Technology

Cosecant squared antenna technology has great
potential to reduce real practical limits to
efficiency at UHF and above
csc2 technology, developed at WWII MIT Radiation
Laboratory and used in GPS, results in relatively
uniform pfd over a large area
Requires vertical length of 10?

8
csc2 Antenna Technology

Good design of vertical pattern of antennas can
limit dynamic range of signals near antenna sites
For example, UHF TV transmitters have moderate
PFDs near antenna despite 5 MW EIRP

9
csc2 Antenna Technology

csc2 technology is practical at
f gt 1 GHz and could be used productively in
many applications to improve spectrum efficiency
New computer algorithms simplify antenna
synthesis

www.remec.com/pdfs/LMDS20ShapeBeam.pdf
10
csc2 Antenna Technology

Near/far problems are generally externalities
and little incentive for licensees to control
them
Not aware of any regulations that encourage or
require pfd control for terrestrial systems
But satellite pfd limits exist
Few products available at present
Possible chicken or egg problem

11
Examples of Products
2 GHz
28 GHz
12
Conclusions