Subject: [NEXTEL-1] REMEC On Overcoming Interference Problems

From: [email-masked]
Date: Thu, 07 Aug 2003 13:38:18 -0400

Finially someone talking about the core issues.
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Nextel: Overcoming Interference Problems

With Public Safety Radio Services

It is our understanding that Nextel has experienced significant interference
issues in areas where its mobile services bands are adjacent to public safety
bands. REMEC believes that these problems are caused by antenna elevation patterns
and down-tilt techniques that result in uneven and excessive receive RF power
density at ground level at varying distances from the tower.
REMEC has developed design capability using electromagnetic design programs
coupled with artificial intelligence algorithms. REMEC currently offers null
filled and cosecant squared elevation pattern antennas for broadband
communications and is able to apply these techniques to mobile communications
bands. Preliminary design of an antenna with null-filled elevation and very
tightly controlled sector azimuth patterns show that REMEC could offer Nextel
replacement antennas that would significantly decrease interference with public
safety services without any need to relocate those services. These antennas have
well behaved patterns that evenly distribute the RF energy on the ground with
distance from the tower. Due to the tight control of the close-in side lobes the
interference levels are dramatically reduced.

REMEC is prepared to design and manufacture these antennas for Nextel. REMEC also
believes that these antennas would have benefits for other carriers with cellular
“A Block” spectrum deploying digital services in the vicinity of public safety
services.

Plots of the antenna patterns, receive power density, and receive power vs.
distance from the tower are submitted as a part of this submission.

For further information, please contact:
Allen E. Rosenzweig
REMEC, Inc.
1590 Buckeye Drive
Milpitas, CA 95035
Tel: 408-501-1111
FAX: 408-432-1551
E-mail: [email-masked]

Radiation patterns

Figure 1. Cosecant squared approximated elevation pattern.
The following plots show the power received at ground level as a function of
distance from the tower. The power levels close in to the tower are shown in
detail in Figure 4.

The antenna would be about 4 to 6 feet tall depending on the gain requirements and
10 to 18 inches wide depending on the azimuth pattern requirements. The estimated
production price is in the range of $700 to $1500 depending on options and
quantities.

Figure 2. Received power at ground level out to 300 meters from the antenna tower
for a 60degree Remec antenna. The transmit power is+40dBm, the base station
antenna gain is 16dBi, and the receive antenna gain is 0dBi. The tower is 25
meters high.

Figure 3. Received power at ground level out to 3000 meters from the antenna tower
for a 60degree Remec antenna. The transmit power is+40dBm, the base station
antenna gain is 16dBi, and the receive antenna gain is 0dBi. The tower is 25
meters high.

Figure 4. Received power at ground level out to 300 meters from the antenna tower
for a 60degree Remec antenna. The transmit power is+40dBm, the base station
antenna gain is 16dBi, and the receive antenna gain is 0dBi. The tower is 25
meters high.

Figure 5. Received power at ground level out to 1000 meters from the antenna tower
for a 60degree Remec antenna. The transmit power is+40dBm, the base station
antenna gain is 16dBi, and the receive antenna gain is 0dBi. The tower is 25
meters high.

http://svartifoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514382679

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