RE: stds-802-16-tg4: Interference and Mechanisms For Sharing the middle UNII band
What follows is a proposed approach for the PHY Layer Section 7.0 on
Interference and Mechanism for Mitigating Interference.
Your comments and contributions for progressing this important Section are
invited and welcomed
Regards
Demos
Dr. Demosthenes J. Kostas
Director, Industry Standards
Adaptive Broadband Corporation
3314 Dartmouth Ave
Dallas, TX 75205 USA
tel: 214 520 8411
fax: 214 520 9802
__________________________________________________________________
7.0 Interference and Mechanisms For Sharing the middle UNII band
7.10 General
The Wireless HUMAN Standard-based systems that will operate in the middle
U-NII band (5.25-5.35 GHz) will have to share this band with a number of
other systems (e.g., Earth Exploratory Satellite (active) Service (EESS)
Synthetic Aperture Radars (SARs), Wireless HUMAN Standard-based systems,
non-standard point-to-multipoint Broadband Fixed Wireless Access(BFWA)
systems, terrestrial Radars, and IEEE 802.11a , 802.15 and Hiperlan/2
Wireless LANs). As this is a License-Exempt (LE) band these diverse systems
will often be operated in the same geographical area by different operators.
Moreover besides having to meet local Regulatory requirements (e.g., in the
USA the FCC Subpart E Requirements) the Wireless HUMAN Standard-based
systems will also be called to meet global agreements; e.g., from the World
Radiocommunications Conference (WRC).
The goal of this Section is to identify (and where possible quantify) the
interference requirements and identify mechanism that can be used by the
Wireless HUMAN Standard-based systems to successfully share spectrum and
geographical location with the likely to be encountered diverse systems.
7.11 EESS SAR INTERFERENCE REQUIREMENT
This interference Wireless HUMAN interference requirement is considered
first as it stems from the 1997 World Radiocommunications Conference (WRC
'97) that allocated the 5250-5350MHz and 5350-5460 MHz bands on a world
wide-primary basis to radiolocation services. These bands are currently
also allocated on a world wide-primary basis to active space-borne sensors,
including SARs (e.g., SAR 1-4). For the Characteristics of these SARs see
Appendix 2 in ITU-R WP7C/126, "Analysis of Potential interference Between
Spaceborne SARs and Wireless High speed Local Area Networks Around
5.3.GHz.". The "primary basis" classification means that it is a
requirement that must be met by Wireless HUMAN Standard-based systems.
The Subsections that follow identify mechanisms that can be used to enable
the Wireless HUMAN Standard-based systems to meet the interference
requirements of EESS SAR sensors.
7.12 ANTENNA DIRECTIVITY TO MITIGATE INTERFERENCE TO EESS
What follows gives an indication of the interference that Wireless HUMAN
based BFWA systems can cause to SARs operating in Middle U-NII band, and
identify means for minimization of this interference. In particular it has
been shown by published results of ITU-R studies that BFWA antenna
directivity is effective in minimizing interference to SAR-4, (e.g., USA
ITU-R WP7C/24 Contribution). Table 1 shows that use of 6dB antenna
directivity can decrease the SAR-4 interference by 4dB.
Note: The value of antenna directivity that should be specified requires
trade-off studies with the other mechanism. SAR-4 is used because the SAR-4
system is more interference sensitive than SAR-3 and -4, and the SAR-4
center frequency is 5.3GHz.
An approach that can be used in analyzing the interference potential from
Middle U-NII BFWA systems into space-borne SAR-4 receiver is to determine
the worst case signal power received from a single BFWA transmitter at the
spaceborne SAR. Then, the single interferer margin can be calculated by
comparing the single BFWA interferer level with the SAR-4 interference
threshold. Knowing the SAR-4 footprint, the allowable density of active
BFWA transmitters can then be calculated, if a positive margin results from
a single BFWA interferer.
Table 1. Interference from a Single U-NII BFWA Transmitter to
SAR-4
7.13 DFS TO MITIGATE INTERFERENCE
7.14 TRANSMITTED POWER CONTROL TO MITIGATE INTERFERENCE
7.15 ANTENNA POLARIZATION TO MITIGATE INTERFERENCE
7.16 TURNING OFF WIRELESS HUMAN SYSTEMS WHEN SPACEBORNE SAR IS IN THE
AREA
7.17 OTHER ... TO MITIGATE INTERFERENCE