United States of America

**proposal for the work of the conference**

**Agenda Item 1.5**: to consider, in accordance with Resolution **736
(WRC-2000)**, regulatory provisions and spectrum requirements for new
and additional allocations to the mobile, fixed, Earth
exploration-satellite and space research services, and to review the
status of the radiolocation service in the frequency range
5 150--5 725 MHz, with a view to upgrading it, taking into account the
results of ITU-R studies;

**Background Information**: At WRC-2000 there were several proposals for
items to be placed on the WRC-03 agenda dealing with spectrum in the 5
GHz range. These items included new allocations to the mobile service
for Wireless Access Systems (WAS) including Radio Local Area Networks
(RLAN) and the fixed service for Fixed Wireless Access (FWA) in Region
3, an additional allocation to the Earth exploration-satellite service
(EESS) (active) and space research service (SRS) (active), and an
upgrade of the radiolocation allocation in the 5 350--5 650 MHz band.

Technology has evolved to the point where wireless local area networks
can be readily and inexpensively deployed to support the businessman or
student that is in a campus environment. These devices are becoming
widely used in some parts of the world, particularly in North America
and Europe. In the United States, for example, WAS devices are permitted
to operate on an unlicensed, non-interference basis in the 5 150--5 350
and 5 725--5 825 MHz bands

Studies show that the presence of outdoor wireless access system
transmitters can cause significant interference to spaceborne active
sensors that operate in the EESS and SRS. ITU-R studies have also shown
that WAS devices will interfere with radiolocation systems that operate
in the 5 250--5 725 MHz band, without appropriate interference
mitigation mechanisms being applied.

Considerable effort has been focused within the last two years in the
ITU-R to determine if sharing is feasible between diverse services such
as radiodetermination and WAS including RLAN. Automated interference
mitigation systems such as Dynamic Frequency Selection (DFS) have been
proposed to enable sharing on a primary basis between WAS including
RLANs and the incumbent services. DFS refers to circuitry within the WAS
device that measures the level of unwanted received energy and compares
this level to a threshold in order to determine if interference sources
are present. These measurements are made during "quiet" times, i.e.,
when WAS traffic is not present. If the level of unwanted received
energy exceeds a predetermined threshold level, the WAS system ceases to
use the affected channel and moves traffic to another channel that does
not have excess levels of unwanted energy.

The risk to incumbent services can be greatly reduced by a) limiting the
new mobile allocation to 5** **150-5** **350 MHz, b) requiring all WAS
including RLAN devices to be equipped with DFS with technical
specifications that maintain an acceptable interference to noise ratio
at the incumbent receivers, and c) including regulatory text in a
footnote that requires WAS including RLAN devices to accept interference
from and not cause interference to other services. Incorporating these
protection methods will enable exploration of new technology to proceed
while managing risk to essential services currently in the 5 GHz band.
See Resolution **\[5GHz_WAS1\]**.

It should be noted that studies on the effectiveness of interference
mitigation mechanisms to protect other services are ongoing in the ITU-R
and that no decision on an allocation to the mobile service for use by
WAS in the 5 470-5 725 MHz band should be made until these studies are
completed and the effectiveness of DFS to protect existing services is
demonstrated. See proposed Resolution **\[5GHz_WAS2\]**.

Concerning FWA in Region 3, preliminary ITU-R studies of radiolocation
sharing with FWA have shown that large separation distances or other
mitigation techniques such as receiver standards or error-correction
coding are required to prevent mutual interference. The band 5 250 --
5 350 MHz, therefore, should not be allocated to the fixed service for
the implementation of fixed wireless access systems at this time.

Active microwave sensors on board spacecraft are an increasingly
important tool for monitoring the Earth\'s environment and oceans
through the determination of wave height and oceanic currents as well as
for radar imaging of the Earth's surface. The need for additional
spectrum adjacent to the current international allocation is well
documented within the ITU-R for enhanced vertical resolution for
spaceborne altimeters and enhanced horizontal resolution for synthetic
aperture radars (SARs). Studies and past operational experience has
shown that operation of these services in bands allocated to the
radiolocation, radionavigation, and aeronautical radionavigation
services has proven to be feasible. Therefore allocation of the EESS
(active) and the SRS (active) in the 5 460-5 470 MHz band is
appropriate.

In regard to additional spectrum allocations for the earth
exploration-satellite service (active) and the space research service
(active) above 5** **470 MHz, the United States has not yet completed
its considerations.

WRC-97 first considered the possibility of an allocation-status upgrade
for the radiolocation service in the 2 900--3 400 MHz and 5 350--5 650
MHz bands by placing this matter on the draft WRC-2001 Agenda. A need
for 600 MHz of additional primary radiolocation spectrum for
radiolocation systems has been determined. Changes in technology are
driving the need for larger bandwidth in order to be able to pick
smaller and less reflective radar targets out of background clutter.
Experience and studies have shown that the radiolocation service can
successfully share the band 5 350--5 650 MHz with existing services.

With protection of current services in mind, while balancing the need to
explore new technologies, the United States proposes the following for
agenda item 1.5:

**Proposal:**

## Article 5

**Frequency Allocations**

+-------------+--------------+---------------------+------------------+
|             | **5 150-5    |                     |                  |
|             | 350 MHz**    |                     |                  |
+-------------+--------------+---------------------+------------------+
|             | **Allocation |                     |                  |
|             | to           |                     |                  |
|             | services**   |                     |                  |
+-------------+--------------+---------------------+------------------+
|             | **Region 1** | **Region 2**        | **Region 3**     |
+-------------+--------------+---------------------+------------------+
| USA/ / 1    | **5          |                     |                  |
|             |  150-5 250** |                     |                  |
| MOD         | [^1]         |                     |                  |
|             | AERONAUTICAL |                     |                  |
|             | RAD          |                     |                  |
|             | IONAVIGATION |                     |                  |
|             |              |                     |                  |
|             | FIX          |                     |                  |
|             | ED-SATELLITE |                     |                  |
|             | SERVICE      |                     |                  |
|             | (Ear         |                     |                  |
|             | th-to-space) |                     |                  |
|             | 5.447A       |                     |                  |
|             |              |                     |                  |
|             | [MOBILE]     |                     |                  |
|             | {.underline} |                     |                  |
|             |              |                     |                  |
|             | 5.446 5.447  |                     |                  |
|             | 5.447B       |                     |                  |
|             | 5.447C       |                     |                  |
|             | \[**ADD**    |                     |                  |
|             | [5.447x]     |                     |                  |
|             | {.underline} |                     |                  |
|             | [5.447y\]]   |                     |                  |
|             | {.underline} |                     |                  |
+-------------+--------------+---------------------+------------------+
| USA/ / 2    | **5          |                     |                  |
|             |  250-5 255** |                     |                  |
| MOD         | EARTH        |                     |                  |
|             | EXPLORATI    |                     |                  |
|             | ON-SATELLITE |                     |                  |
|             | (active)     |                     |                  |
|             |              |                     |                  |
|             | R            |                     |                  |
|             | ADIOLOCATION |                     |                  |
|             |              |                     |                  |
|             | SPACE        |                     |                  |
|             | RESEARCH     |                     |                  |
|             | 5.447D       |                     |                  |
|             |              |                     |                  |
|             | [MOBILE]     |                     |                  |
|             | {.underline} |                     |                  |
|             |              |                     |                  |
|             | 5.448        |                     |                  |
|             | ~~5.448A~~   |                     |                  |
|             | **ADD**      |                     |                  |
|             | [5.USA3]     |                     |                  |
|             | {.underline} |                     |                  |
+-------------+--------------+---------------------+------------------+
| USA/ / 3    | **5 255-     |                     |                  |
|             | 5 350**      |                     |                  |
| MOD         | EARTH        |                     |                  |
|             | EXPLORATI    |                     |                  |
|             | ON-SATELLITE |                     |                  |
|             | (active)     |                     |                  |
|             |              |                     |                  |
|             | R            |                     |                  |
|             | ADIOLOCATION |                     |                  |
|             |              |                     |                  |
|             | SPACE        |                     |                  |
|             | RESEARCH     |                     |                  |
|             | (active)     |                     |                  |
|             |              |                     |                  |
|             | [MOBILE]     |                     |                  |
|             | {.underline} |                     |                  |
|             |              |                     |                  |
|             | 5.448        |                     |                  |
|             | ~~5.448A~~   |                     |                  |
|             | **ADD**      |                     |                  |
|             | [5.USA3]     |                     |                  |
|             | {.underline} |                     |                  |
+-------------+--------------+---------------------+------------------+

**Reasons**: The deletion of the footnote **5.448A** is justified based
on the sharing situation between the EES (active) and the SR (active)
services and the radiolocation service in the band 5 250--5 350 MHz.
These two services were found to be compatible in ITU-R studies for the
band 5 250--5 350 MHz making footnote **5.448A** unnecessary.

A new mobile allocation in the band 5 150-5 350 MHz will facilitate
exploration of the use of DFS to enable sharing between WAS including
RLANs and the incumbent services with appropriate protection methods as
stated in **5.USA3**. Footnote **5.USA3** addresses protection of
incumbent services by requiring all WAS including RLAN devices to be
equipped with DFS with technical specifications that maintain an
interference to noise ratio of --6 dB at the incumbent radiolocation
receivers, and regulatory requirements for WAS including RLAN to accept
interference from and not cause interference to radiolocation, Earth
exploration satellite and space research services.

+----------+------------------+------------------+--------------------+
|          | **5 350-5 725    |                  |                    |
|          | MHz**            |                  |                    |
+----------+------------------+------------------+--------------------+
|          | **Allocation to  |                  |                    |
|          | services**       |                  |                    |
+----------+------------------+------------------+--------------------+
|          | **Region 1**     | **Region 2**     | **Region 3**       |
+----------+------------------+------------------+--------------------+
| USA/ / 4 | **5 350-5 460**  |                  |                    |
|          | EARTH            |                  |                    |
| MOD      | EXPLO            |                  |                    |
|          | RATION-SATELLITE |                  |                    |
|          | (active)         |                  |                    |
|          | ~~5.448B~~       |                  |                    |
|          | AERONAUTICAL     |                  |                    |
|          | RADIONAVIGATION  |                  |                    |
|          | 5.449            |                  |                    |
|          |                  |                  |                    |
|          | [RADIOLOCAT      |                  |                    |
|          | ION]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | [SPACE RESEARCH  |                  |                    |
|          | (acti            |                  |                    |
|          | ve)]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | ~                |                  |                    |
|          | ~Radiolocation~~ |                  |                    |
|          |                  |                  |                    |
|          | **ADD**          |                  |                    |
|          | [5.U             |                  |                    |
|          | SA1]{.underline} |                  |                    |
|          | **ADD**          |                  |                    |
|          | [5.U             |                  |                    |
|          | SA2]{.underline} |                  |                    |
+----------+------------------+------------------+--------------------+
| USA/ / 5 | **5 460-5 470**  |                  |                    |
|          | [EARTH           |                  |                    |
| MOD      | EXPLO            |                  |                    |
|          | RATION-SATELLITE |                  |                    |
|          | (acti            |                  |                    |
|          | ve)]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | [RADIOLOCAT      |                  |                    |
|          | ION]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | [SPACE RESEARCH  |                  |                    |
|          | (acti            |                  |                    |
|          | ve)]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | RADIONAVIGATION  |                  |                    |
|          | 5.449            |                  |                    |
|          |                  |                  |                    |
|          | ~                |                  |                    |
|          | ~Radiolocation~~ |                  |                    |
|          |                  |                  |                    |
|          | ####  **ADD** [  |                  |                    |
|          | 5.USA1]{.underli |                  |                    |
|          | ne} **ADD** [5.U |                  |                    |
|          | SA2]{.underline} |                  |                    |
+----------+------------------+------------------+--------------------+
| USA/ / 6 | **5 470- 5 570** |                  |                    |
|          | MARITIME         |                  |                    |
| MOD      | RADIONAVIGATION  |                  |                    |
|          |                  |                  |                    |
|          | [RADIOLOCAT      |                  |                    |
|          | ION]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | ~                |                  |                    |
|          | ~Radiolocation~~ |                  |                    |
|          |                  |                  |                    |
|          | ####  5.         |                  |                    |
|          | 450 5.451 5.452  |                  |                    |
+----------+------------------+------------------+--------------------+
| USA/ / 7 | **5 570-5 650**  |                  |                    |
|          | MARITIME         |                  |                    |
| MOD      | RADIONAVIGATION  |                  |                    |
|          |                  |                  |                    |
|          | [RADIOLOCAT      |                  |                    |
|          | ION]{.underline} |                  |                    |
|          |                  |                  |                    |
|          | ~                |                  |                    |
|          | ~Radiolocation~~ |                  |                    |
|          |                  |                  |                    |
|          | 5.450 5.451      |                  |                    |
|          | 5.452            |                  |                    |
+----------+------------------+------------------+--------------------+
| USA/ / 8 | **5 650-5 725**  |                  |                    |
|          | RADIOLOCATION    |                  |                    |
| [        |                  |                  |                    |
| NOC]{.un | Amateur          |                  |                    |
| derline} |                  |                  |                    |
|          | Space research   |                  |                    |
|          | (deep space)     |                  |                    |
|          |                  |                  |                    |
|          | 5.282 5.451      |                  |                    |
|          | 5.453 5.454      |                  |                    |
|          | 5.455            |                  |                    |
+----------+------------------+------------------+--------------------+

**Reasons**: The existing allocation of the band 5 350--5 650 MHz to the
radiolocation service on a secondary basis should be upgraded to primary
status as studies have shown that the radiolocation service is
compatible with existing primary services in this frequency range.

The band 5 350--5 460 MHz should be allocated to the SRS (active) on a
primary basis as the sharing situation is identical to that of the
previously allocated EESS (active) and this band is needed to make a
contiguous allocation for the SRS (active). The band 5 460--5 470 MHz
should be allocated to the EESS (active) and the SRS (active) on a
primary basis as studies have shown that spaceborne active sensors
operating in these services can share the band with the radars operating
in the radionavigation and radiolocation services as long as the active
sensors meet the design criteria and utilize the mitigation techniques
given in Recommendation ITU-R SA.1280. Footnote **5.USA1** is added in
order to ensure the protection of these services in their various
allocated bands.

The band 5 470--5 725 MHz should not be allocated at this time to the
mobile service for the implementation of wireless access systems
including RLANs. Further actions in this band should be considered at
the next WRC after exploration of the feasibility of DFS in the band
5 250-5 350 MHz. Resolution \[**5GHz_WAS2**\], attached, provides a
sample resolution that could be utilized for further consideration of
mobile implementation in the 5 470-5 725 MHz band.

## USA/1.6 /1 ADD *(Shown for information only. See U.S. proposal for agenda item 1.6)*

**\[*5.447x*** *In order to protect the non-GSO MSS feeder links
(Earth-to-space) in 5* *150-5* *250 MHz from interference caused by
devices and stations in the fixed and mobile services, the following
measures shall be taken:*

*i) these devices shall be limited to a maximum average e.i.r.p. of 23
dBm and a maximum average e.i.r.p. spectral density of 10 dBm in any 1
MHz;*

*ii) these devices shall be limited to indoor applications only;*

iii) *for signals with occupied bandwidths of 1 MHz or less, the
     e.i.r.p. spectral density, in the occupied bandwidth B in MHz,
     shall not exceed 10 dBm + 10log~10~(B) (dBm/B MHz);*

***Reasons**: To provide reasonable regulatory measures for the
protection of MSS feeder links (Earth-to-space) from interference from
mobile and fixed transmitters while not unduly burdening the growth of
those services.*\]

## USA/1.6/2 ADD *(Shown for information only. See U.S. proposal for agenda item 1.6)*

**\[*5.447y*** *Administrations should take into account the provisions
of Recommendation ITU-R S.1426 for the protection of non-GSO MSS feeder
links (Earth-to-space) in the 5 150-5 250 MHz band.*

***Reasons**: To provide reasonable regulatory measures for the
protection of MSS feeder links (Earth-to-space) from interference from
mobile and fixed transmitters while not unduly burdening the growth of
those services.*\]

**USA/ / 9 SUP**

**5.448A**

**Reasons**: There is no technical justification for this footnote that
was adopted at WRC-97.

### USA/ / 10 SUP

**5.448B**

**Reasons**: This footnote is replaced with the new footnote **5.USA1**
that clarifies the sharing situation between EESS (active), SRS
(active), and the other allocated services in these bands.

### USA/ / 11 ADD

**5.USA1** The Earth exploration-satellite (active) and space research
(active) services operating in the frequency range 5 350-5 470 MHz shall
not cause harmful interference to, or claim protection from harmful
interference from operations in accordance with **5.449**. Additionally,
the Earth exploration-satellite (active) and space research (active)
services operating in the frequency range 5 460-5 470 MHz shall not
cause harmful interference to the radiolocation service and should take
into account Recommendation ITU-R SA.1280.

**Reasons**: If spaceborne active sensors operating in the EESS (active)
and SRS (active) adhere to the design considerations and mitigation
techniques found in Recommendation ITU-R SA.1280, the radiolocation,
aeronautical radionavigation and radionavigation services (**5.449**)
will be protected from harmful interference and will not be constrained
in any manner.

####### USA/ / 12 ADD

**5.USA2** in the frequency band 5 350-5 470 MHz, stations in the
radiolocation service shall not cause harmful interference to, or claim
protection from stations in the aeronautical-radionavigation service
operating in accordance with **5.449**.

**Reasons**: This footnote defines the aeronautical-radionavigation
service operations as having priority over the radiolocation service in
the 5 350-5 470 MHz band. The radiolocation operations cannot cause
interference to aeronautical-radionavigation systems, nor can the
radiolocation service claim protection from the
aeronautical-radionavigation service operating in accordance with
**5.449**.

####### USA/ /13 NOC

**5.452** Between 5 600 MHz and 5 650 MHz, ground-based radars used for
meteorological purposes are authorized to operate on a basis of equality
with stations of the maritime radionavigation service.

**Reasons**: Many administrations use the band 5 600--5 650 MHz for
these meteorological radars and this usage should be preserved.

### USA/ / 14 ADD

**5.USA3** in the frequency bands 5 250-5 350 MHz, stations in the
mobile service shall not cause interference to and must accept
interference from stations in the radiolocation, Earth exploration
satellite and space research services (active) services. All mobile
devices utilizing these bands shall operate only if equipped with an
automated interference mitigation technique that meets the minimum
standards as defined in Resolution \[**5GHz_WAS1**\]. Technical
requirements for DFS include adherence to the following criteria:

1\. DFS detection threshold of --67 dBm.

2\. DFS integration period of less than 1 microsecond.

3\. WAS including RLAN channel move time of 10 seconds.

4\. WAS including RLAN channel availability check time of 60 seconds.

5\. WAS including RLAN channel non-occupancy period of 30 minutes.

**Reasons**: To provide regulatory measures for the protection of the
existing co-primary services from harmful interference from wireless
access systems, including RLANs, authorized under the proposed
(restricted) mobile allocation.

**USA/ / 15 ADD**

RESOLUTION \[5GHz_WAS1\] (WRC-03)

MEASURES TO BE TAKEN BY THE MOBILE SERVICE FOR THE OPERATION OF STATIONS
IN THE BAND 5 250 -- 5 350 MHz

The World Radiocommunication Conference (Geneva, 2003),

*considering*

a)  The need to provide globally harmonized spectrum to the mobile
    service for wireless access systems, including RLANs at 5 250-5 350;

b)  the need to protect existing and planned radiodetermination systems
    in the band 5 250-5 350 MHz;

c)  the need to protect existing and planned Earth exploration-satellite
    service (active) and space research service (active) in the band
    5 250-5 350 MHz;

d)  that studies have shown that sharing between these services is only
    possible with the application of mitigation techniques such as
    Dynamic Frequency Selection (DFS);

e)  Other mitigation techniques may provide sharing approaches which
    would need to be examined by administrations to determine if
    adequate protection is afforded to radiodetermination and Earth
    exploration-satellite service (active) and space research service
    (active),

*noting*

a)  that administrations may already allow operations for mobile devices
    in portions of the 5 150-5 350 and 5 470-5 725 MHz bands;

b)  the need for administrations to develop acceptance testing of
    devices employing DFS to ensure these devices meet the required
    operational characteristics,

*resolves*

1\) that the mitigation measures found in Annex 1 shall be utilized by
devices in the mobile service operating in the 5 250-5 350 MHz band and
using for the example the approach in Annex 2;

2**)** that mobile devices operating in the 5 250-5 350 MHz band shall
have the following technical characteristics - Indoor/outdoor operations
with peak transmit power of 250 mW or 11 dBm + 10xlogB (where B=26 dB
emission bandwidth in MHz ) and a maximum average e.i.r.p of 30 dB or 17
dBm in any 1 MHz). For signals with occupied bandwidths of 1 MHz or
less, the e.i.r.p. spectral density, in the occupied bandwidth B in MHz,
shall not exceed 17 dBm + 10log~10~(B) (dBm/B MHz).

ANNEX 1 TO RESOLUTION \[5GHz_WAS1\] (WRC-03)

The use of dynamic frequency selection (DFS) in wireless access systems
including RLANs for the purpose of protecting the radiodetermination\
service in the 5 250--5 350 MHz Band

### Scope of this Annex {#scope-of-this-annex .heading_b}

In order to ensure protection radiodetermination and EES/SR (active)
services specific technical mitigation techniques are required. Mobile
systems in the 5 250-5 350 MHz band will employ DFS. An example of how a
DFS mechanism could be described is given in Annex 2.

The specific technical implementation of radar detection mechanisms and
procedures used by WAS are outside the scope of this annex. The main
reasons for this are that:

a\) WAS design affects implementation;

b\) practical experience may lead to innovative and more efficient means
than can be formulated today;

c\) different manufacturers may make different implementation choices to
achieve the lowest cost for a given level of performance; therefore only
performance criteria rather than specifications for a particular
mechanism should be given in regulatory documents.

### Objective of the use of DFS with respect to radars {#objective-of-the-use-of-dfs-with-respect-to-radars .heading_b}

The objective of using DFS in WAS is to protect radiodetermination
service operations in the 5 GHz band. This is achieved by avoiding the
use of or vacating a channel identified as being occupied by radar
equipment based on detection of radar signals.

### DFS Performance Requirements {#dfs-performance-requirements .heading_b}

The DFS performance requirement is stated in terms of response to
detection of an interference signal. 5 GHz WAS shall meet the following
detection and response requirements listed below.

Procedures for compliance verification should be incorporated in
relevant industry standards for RLANs.

### Detection Requirement {#detection-requirement .heading_b}

The DFS mechanism shall be able to detect interference signals above a
minimum threshold. Radar signal detection criteria as specified below:

**1 Detection Criteria**

\- the received signal strength (RSS) shall be greater than a DFS
detection threshold level of -67 dBm within the WAS channel bandwidth
averaged over a period of less than 1 s;

\- pulse repetition rates in the range 200-400 pulses per second;

\- nominal pulse widths in the range 1‑100 s.

**2 Behavioral Criteria**

The following table provides values for the specified parameters
associated with the behavior of WAS. The operating procedures and the
definition of these parameters are given in the Annex 2.

  ------------------------------------------------ ----------------------
  Parameter                                        Value

  DFS Detection Threshold                          -67 dBm

  Channel Availability Check time                  60 sec prior to use of
                                                   channel

  Non-occupancy Period                             30 min

  Channel Move Time                                10 sec
  ------------------------------------------------ ----------------------

### Response Requirement {#response-requirement .heading_b}

If the WAS has not previously been in operation, it shall not start
transmission in any channel where the detection mechanism has determined
that there is a radar signal present.

NOTE − For WAS to resume operation on another channel in a coordinated
fashion, some communication is required between the devices making up
the WAS. Thus, operational traffic can be stopped very quickly upon
detection of the radar signal, but some intermittent control traffic
will be needed after that.

ANNEX 2 TO RESOLUTION \[5GHz_WAS1\] (WRC-03)

Example radar detection and associated DFS procedures

The purpose of this annex is to describe how a WAS *could* implement
radar detection and the associated procedures for clearing a channel so
as to avoid interfering with a radar system. The actual operation may
vary with the type of WAS and with the actual design of a specific RLAN
implementation, however, the general definitions and rules described in
this annex should be followed.

The description is given in terms of a set of ***definitions*** and
***rules.***

# **1 Definitions**

The following definitions are given for use within this document:

Available Channel A radio channel on which a *Channel Availability
Check* has not identified the presence of a radar.

Channel Availability Check A check during which the WAS listens on a
particular radio channel to identify whether there is a radar operating
on that radio channel.

In-Service Monitoring Monitoring of the *Operating Channel* to check
that a co-channel radar has not moved or started operation within range
of the WAS.

Received Radar Signal A signal as defined in Section 1 of Appendix
**2**. This definition contains parameters for the received signal
strength (field strength) threshold, pulse duration and pulse repetition
rate.

Operating Channel Once a WAS starts to operate on an *Available Channel*
then that channel becomes the *Operating Channel*.

Channel Move Time The time needed by a WAS to cease all transmissions on
the Operating Channel upon detection of an interfering signal above the
DFS detection threshold. Transmissions during this period will consist
of intermittent management and control signals required to facilitate
vacating the Operating Channel.

DFS Detection Threshold The required detection level defined by
detecting a received signal strength (RSS) that is greater than a
threshold specified, within the WAS channel bandwidth.

Non-Occupancy Period The required period in which, once a channel has
been recognized as containing a radar signal by a WAS, the channel will
not be selected as an available channel.

**2 Procedures**

## 2.1 Finding an initial Available Channel

Before operating a WAS station must identify at least one *Available
Channel*. Having identified an *Available Channel*, the WAS can start
operation on that channel; the checking of other radio channels to
identify other *Available Channels* is optional.

## 2.2 Starting Operation

Once a WAS starts to operate on an *Available Channel* then that channel
becomes the *Operating Channel*.

## 2.3 Monitoring the Operating Channel

*In-Service Monitoring* is performed by the WAS to re-check the
*Operating Channel* for co-channel radar signals that may have come
within range of the WAS or started operation on the *Operating Channel*
WAS transmits, and if no *Available Channel* has yet been identified, it
shall undertake a *Channel Availability Check* on a radio channel before
it is used for transmission. Consequently, when a network is installed
and first powered on, *Channel Availability Check*(*s*) should be
undertaken.

# **3 Implementation Aspects**

WAS should incorporate the following mechanisms in order to fulfill
radar interference mitigation:

\- Means to perform the detection of signals that meet the
specifications in this Resolution.

\- Means to inform the associated stations of the WAS of the presence of
a radar and/or change of status of the *Operating Channel* and of the
status of other Channels.

## 3.1 Radar Signal Detection

Radar signals may occur at any time and they may occur in the presence
of co-channel WAS signals. While finding an initial *Available Channel*,
the WAS will not be operational and this will assure rapid and reliable
detection of any radar signal with the possible exception of very slowly
rotating radars. However, these will be detected by the *In-Service
Monitoring*.

During *In-Service Monitoring* the radar detection function continuously
searches for radar signal patterns - during or in between normal WAS
transmissions by averaging detected power over a period of less than 1
s. For weak received radar signals, this may increase the time needed
for radar signal detection. This is reflected in the criteria in this
Resolution. Once a radar has been detected on a particular channel it
will be marked for the *Non-occupancy Period* to ensure that an existing
radar has not changed operational mode giving a false indication that
the channel is available.

## 3.2 Channel Move Time

Every WAS has at least one device - e.g. an Access Point - that plays a
coordinating role. This device also has the responsibility to
coordinate, after a radar presence has been detected, the cessation of
use of the *Operating Channel* and the move to an *Available Channel*.

Such coordination requires the broadcasting of commands to cease all
operational transmission and to affect a move to (one of) the *Available
Channels* identified by the *Channel Availability Check*. This broadcast
will be repeated a number of times to assure reception by all member
devices. Part of the RLAN population may be in so-called **Sleep Mode**
in which the devices re-awaken at intervals of typically hundreds of
milliseconds but extremes of up to 60 seconds are possible. Disregarding
the latter, the broadcast has to be repeated a number of times during
the *Channel Move Time* to assure that for all practical purposes, all
of the RLAN devices will have left the channel.

USA/ / 16 ADD

RESOLUTION \[5GHz_WAS2\] (WRC-03)

CONSIDERATION BY A FUTURE COMPETENT WORLD RADIOCOMMUNICATION CONFERENCE
CONCERNING AN ALLOCATION TO THE MOBILE SERVICE IN THE BAND 5 470--5 725
MHz

The World Radiocommunication Conference (Geneva, 2003),

*considering*

a)  The need to provide globally harmonized spectrum to the mobile
    service for wireless access systems, including RLANs at 5 470-5 725
    MHz;

b)  the need to protect existing and planned radiodetermination systems
    in the band 5 470-5 725 MHz

c)  that studies have shown that sharing between services in the
    5 470-5 725 MHz is only possible with the application of mitigation
    techniques such as Dynamic Frequency Selection (DFS);

d)  that in the future, other mitigation techniques may provide sharing
    approaches which will need to be examined to determine if adequate
    protection is afforded to other services,

*noting*

administrations may already allow operations for mobile devices in
portions of the 5 470-5 725 MHz band;

*resolves*

that based on proposals from administrations and taking into account the
results of continued studies in ITU and the Conference Preparatory
Meeting, WRC-\[07\] should consider:

1.  allocation of frequencies to the mobile service in the band
    5 470-5 725 MHz for the implementation of wireless access systems
    including RLANs;

2.  adoption of necessary provisions for wireless access systems
    including RLANs to protect other services in the 5 470-5 725 MHz
    band;

> *Invites ITU-R*

to continue, and complete in time for WRC-\[07\], the appropriate
studies leading to technical and operational recommendations to
facilitate sharing between wireless access systems including RLANs and
other services.

[^1]: Additional proposals for the band 5150-5250 are contained in USA
    proposals for agenda item 1.6 and are reproduced here for
    information.