doc.: IEEE 802.11-03/029r0
January 2003
New Radio Measurement Actions
within the 802.11h Framework
Daryl Kaiser (Cisco Systems)
14 January 2003
Submission
Page 1
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Purpose
• To review the radio measurement actions proposed in 02/677r2
• To show how these measurements fit the 802.11h framework
• In particular, the measurement request/report infrastructure
Submission
Page 2
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Wireless network goals that require radio measurement action
Detect possible rogue APs to help the WLAN administrator plug
security holes
Quantify WLAN radio topology to facilitate automatic frequency
selection and AP/client power limits
Measure BSS overlap to feed BSS overlap mitigation (TGe) and to
help balance coverage, capacity and QoS
Quantify each station’s local performance to assist admissions
control (TGe) and to facilitate roaming and load balancing
Detect non-802.11 interference and quantify noise to facilitate radio
parameter avoidance and to inform mobile clients of situation
Submission
Page 3
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Summary of proposed radio measurement actions (02/677r2)
• Beacon report detects possible rogue APs, quantifies WLAN radio
topology and measures BSS overlap
• Extended CCA report quantifies each station’s current local
performance in terms of CCA busy fraction and backoff experience
• Non-802.11 RPI histogram report detects non-802.11 interference
and quantifies noise
• Frame report identifies a station’s local contending stations
• Reducing to one-liners:
– What do you hear (and how much of it)? Extended CCA and RPI Histogram reports
– Who do you hear? Beacon and Frame reports
Submission
Page 4
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
802.11h defines an infrastructure for measurement requests
and measurement reports
Measurement Request frame
Measurement Report frame
Element
… Element
Element
… Element
Params
Params
Params
Params
…
One or more Measurement
Request elements per frame
Measurement Report frame
One or more Measurement
Report elements per frame
Submission
Page 5
Element
… Element
Params
Params
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
TGk would use the same measurement request format as
802.11h
Add a category…and request/report actions
Category
Action
Dialog
Token
Activation
Delay
Measurement
Offset
One or more
Measurement Request elements
1
1
1
1
1
variable
• Category: 0=Spectrum Mgmt(TGh), 1=QoS Mgmt(TGe), 2=DLP(TGe), 3=Radio Measurement(TGk)
• Action: TGh and TGe define actions unique to their categories, TGk=Measurement Request & Report
• Dialog Token indicates the unique identity of the request …All fixed fields follow existing conventions
• Activation Delay indicates the number of TBTTs to skip before executing the first request element
• Measurement Offset indicates the start time offset within the beacon interval
• Measurement Request elements are processed sequentially and executed in series or in parallel
Submission
Page 6
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Why define a new Radio Measurement category?
• To distinguish radar avoidance and radio measurement capability
• Stations advertising Spectrum Management can avoid radars
• Stations advertising Radio Measurement can measure and report
• Some TGh and TGk measurements may be similar, but…
• Ultimately, these are two distinct capabilities
Submission
Page 7
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
TGk would use 802.11h Measurement Request Element ID and
the same fixed field definitions
Add measurement types
Element ID
Length
1
1
Measurement
Token
Measurement
Request Mode
Measurement
Type
1
1
1
Measurement Request
variable
• Measurement Token is unique among the elements in a measurement request frame
• Measurement Request Mode indicates (1) serial vs. parallel and (2) whether the originator wants
to receive measurement requests and autonomous reports from the receiving station
• Measurement Type identifies type of measurement, which defines the remaining format
– 802.11h defines three types: Basic, CCA, and RPI Histogram
– TGk would define new types: Beacon, Extended CCA, Non-802.11 RPI Histogram, Frame
• Measurement Request contains the details of the request
Submission
Page 8
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
TGk measurement request details would include an extra field
Channel
Duration
1
2
Channel
Scan Mode
or Spare
1
1
802.11h measurement request details
Duration
TGk measurement request details
2
• Channel is identical to 802.11h
• Duration is identical to 802.11h
• Scan Mode would choose between passive, active and beacon table retrieval for Beacon
measurement only
• Other TGk measurements would not require Scan mode, and could replace it with a Spare field
or eliminate it altogether
Submission
Page 9
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
TGk would use the same measurement report format as
802.11h
New category
report action
Category
Action
Dialog
Token
One or more
Measurement Report elements
1
1
1
variable
• Category: 0=Spectrum Mgmt(TGh), 1=QoS Mgmt(TGe), 2=DLP(TGe), 3=Radio Measurement(TGk)
• Action: TGh and TGe define actions unique to their categories, TGk=Measurement Request & Report
• Dialog Token indicates the unique identity of the request …This field follows existing convention
• Measurement Report elements contain fixed fields and measurement type-specific fields
Submission
Page 10
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
TGk would use 802.11h Measurement Report Element ID and
the same fixed field definitions
New measurement types
Element ID
Length
1
1
Measurement
Token
Measurement
Report Mode
Measurement
Type
1
1
1
Measurement Report
variable
• Measurement Token is the unique value from the measurement request frame
• Measurement Report Mode indicates (1) serial vs. parallel and (2) whether the reporting STA is
incapable of performing the requested measurement or refuses to perform it
• Measurement Type identifies type of measurement, which defines the remaining format
– Same as in Measurement Request. Three 802.11h types plus new TGk measurement types.
• Measurement Report contains the measurement results
Submission
Page 11
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Some TGk measurement report details would match 802.11h
formats. Others would define new formats. For example, the
new Beacon Report…
Channel
Duration
PHY Type
Received Signal
Strength
BSSID
1
1
1
1
6
Parent TSF
Target TSF
Beacon
Interval
Capability
Information
4
8
2
2
Received Elements
variable
• PHY Type indicates the physical layer type as defined by dot11PhyType
• Received Signal Strength is an absolute measurement in dBm
• BSSID, Beacon Interval and Capability are copied from the received beacon or probe response
• Parent TSF is the lower 4 bytes of the measuring station’s TSFTIMER at time of reception
• Target TSF is the Timestamp field copied from the received beacon or probe response
• Received Elements include other IEs in the received beacon or probe response
Submission
Page 12
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Measurement report details for proposed TGk measurements
• Beacon report would define a new report detail format
• Extended CCA report would include Channel Busy Fraction as in
802.11h, plus the station’s recent backoff history per QoS class
• Non-802.11 RPI histogram report would use the same format as
802.11h, but reflect only non-802.11 interference and noise
• Frame report would define a new report detail format
Submission
Page 13
Daryl Kaiser, Cisco Systems
doc.: IEEE 802.11-03/029r0
January 2003
Summary of how proposed TGk measurement requests and
reports fit the 802.11 framework
• Use action management frames defined by TGh and TGe
• Define a new action category for radio measurements
• Use Measurement Request & Report Element IDs defined by TGh
• Use the same definition of CCA Busy Fraction as TGh
• Use the same report RPI Histogram ranges and format as TGh
Submission
Page 14
Daryl Kaiser, Cisco Systems