November 2002

Richard Paine, Boeing

Slide 1

doc.: IEEE 802.11-02/651r0

Submission

+

Radio Resource MeasurementTutorial

November 2002

Richard Paine, Boeing

Slide 2

doc.: IEEE 802.11-02/651r0

Submission

Agenda

- Why Radio Resource Measurement now?

- 802.11 Existing Measurement Approach

- Proposed Approach

- Requirements

- Issues

- Futures

- Conclusions

November 2002

Richard Paine, Boeing

Slide 3

doc.: IEEE 802.11-02/651r0

Submission

Military Communications NeedsC

onne

ctiv

ityC

onne

ctiv

ity

WIN-TWIN-T

MunitionsMunitionsRoboticsRobotics

SensorsSensors

TacticalTactical

WIN-TWIN-T

TacticalTactical

Unattended Unattended Ground Layer:Ground Layer:

ManeuverManeuverLayer:Layer:

SpaceSpaceLayerLayer::

AirborneAirborneLayer:Layer:

• Assured Communications Anywhere in the World Without Fixed Infrastructure and Zero Setup Time

November 2002

Richard Paine, Boeing

Slide 4

doc.: IEEE 802.11-02/651r0

Submission

RRM Extension Options• RRM blue stars show the likely location of RRM extensions,

though RRM pink stars are (remotely) possible. • RRM Applications are outside the 802.11 specs.

MAC

PLCP

PMD

PLME

PHY SAP

PMD SAP

SME

MLME

PLME SAP

MLM

E S

AP

PLM

E S

AP

MAC SAP

RRM

RRM

RRM

RRM

RRMRRM

Applications(outside 802.11)

November 2002

Richard Paine, Boeing

Slide 5

doc.: IEEE 802.11-02/651r0

Submission

MIBs – current

• 802.11– Basic measurements & configuration for STA– Widely implemented in APs– Very simple monitoring of global AP statistics

• 802.1x– Detailed auth state for individual 1x ports– Also some per port statistics– Not widely implemented in access points today

• Bridge MIB– Possible to get some info on which STAs are associated with

an AP– Implemented in some APs– Not 802.11 specific, little MAC, and no PHY statistics

November 2002

Richard Paine, Boeing

Slide 6

doc.: IEEE 802.11-02/651r0

Submission

Work from existing TGs

• 802.11d– dot11CountryString

• TGe– dot11AssociatedStationCount– dot11ChannelUtilization– dot11FrameLossRate

• TGi– Write only key access, & IV status

• TGh– Configuration, but no status, monitoring or

statistics!!!

November 2002

Richard Paine, Boeing

Slide 7

doc.: IEEE 802.11-02/651r0

Submission

Purpose of additions

• Enable better diagnostics of problems– Using info that is easy and cheap to gather

• Enable better frequency planning, optimize network performance– Enable automatic frequency planning

• Enable new services– Location based services

November 2002

Richard Paine, Boeing

Slide 8

doc.: IEEE 802.11-02/651r0

Submission

Diagnostics

• Interference from non 802.11 sources• Interference from other 802.11 networks• Interference from other APs within

same ESS

November 2002

Richard Paine, Boeing

Slide 9

doc.: IEEE 802.11-02/651r0

Submission

Add station table to MIB

• Station table is list of wireless STAs an AP knows about

• Also applicable to IBSS• Currently implemented by many APs,

as proprietary MIB/telnet/web interface

November 2002

Richard Paine, Boeing

Slide 10

doc.: IEEE 802.11-02/651r0

Submission

Stations Listed in Table

• Only wireless stations listed• Stations that have communicated with this

STA– Authenticating stations– Authenticated stations– Associated stations– WDS links

• Wireless stations known about through DS only (e.g. pre-auth)

November 2002

Richard Paine, Boeing

Slide 11

doc.: IEEE 802.11-02/651r0

Submission

Stations communicated with

• Table includes all stations a station has received any frames from

• For each station expose full state of communication with that station– Pre RSN authentication state– 802.1x port ID

• Further auth info can be found from 802.1x MIB

– Association state– Detailed link statistics

November 2002

Richard Paine, Boeing

Slide 12

doc.: IEEE 802.11-02/651r0

Submission

Link statistics

• dot11MACStatistics• Counts of

– MSDUs/MPDUs received/transmitted– Channel utilization in rx & tx direction

• Measured as total μs

• Data rate & modulation of last rx and tx• RSSI, signal quality• Link margin as seen by other station

– Available for 11h stations– Either use recent measurement report, or request report for

each SNMP request

November 2002

Richard Paine, Boeing

Slide 13

doc.: IEEE 802.11-02/651r0

Submission

Add MAC statistics to MIB

• Channel utilization from TGe• Total associated stations• Total authenticated stations• Optional events to notify mgmt station of

authentication and association events– Current MIB sends TRAPS on assoc/auth

failures

November 2002

Richard Paine, Boeing

Slide 14

doc.: IEEE 802.11-02/651r0

Submission

Events to report

• Allow all events to be configurable as– Not reported– Reported as TRAP (unreliable)– Reported as INFORM (reliable)

• Default configuration should give same events as current 802.11 MIB

• Report all pre RSN auth/deauth events• Report all association/deassocation events

November 2002

Richard Paine, Boeing

Slide 15

doc.: IEEE 802.11-02/651r0

Submission

Requirements Categories

• Data, Voice, Video• Data – QoS, wireless net (a, b, g, h)• Voice – RSSI, S/N, Delay, Jitter, Encryption, device processor, wireless net (a, b, g, h)• Video – RSSI, S/N, Encryption, device processor, wireless net (a, b, g, h)

• Diagnostics (non-802.11, 802.11, other APs)• Access Point Table• Station Table (BSS and IBSS)• Link stats (counts, data rates, RSSI, link margin)• MAC Statistics (channel utilization, total stations, events)• Events (auth, deauth, associate, deassociate, current MIB)• Coexistence Measurements• Retries• Clear Channel Assessment

November 2002

Richard Paine, Boeing

Slide 16

doc.: IEEE 802.11-02/651r0

Submission

Paper Topics• MIBs• Signal Strength• Standardizing RSSI• Real Time Parameters• Real Time Issues• Retries• Measuring Transmission Speeds• Measuring Throughput in WLANs• VOIP Radio Resource Issues• Video Radio Resource Issues• Additional Information needed in the MIBs (802.1x, 802.11, 802.1p)• Diagnostics Needed for Effective Mgt of WLANs

November 2002

Richard Paine, Boeing

Slide 17

doc.: IEEE 802.11-02/651r0

Submission

Relationship of RSSI, Operating Point, Sensitivity, SNR

Received Signal Strength

Operating Margin

Actual Operating Point Multipath observed Impairment SNR Rx Sensitivity Rx Implementation dBm Loss Theoretical Operating Point Actual SNR needed to Theorertical support minimum SNR datarate needed to support datarate

Rx Equivalent Input Noise

Noise Figure

Thermal Noise Floor (-101.5 dBm)

November 2002

Richard Paine, Boeing

Slide 18

doc.: IEEE 802.11-02/651r0

Submission

Goal of Radio Measurement:

•Initial deployment–Enable some degree of automatic radio configuration•Network expansion–Enable some degree of automatic radio reconfiguration•Maintenance/troubleshooting–Provide information to monitor radio performance and fix problems

November 2002

Richard Paine, Boeing

Slide 19

doc.: IEEE 802.11-02/651r0

Submission

Define Radio Configuration:•A set of 802.11 parameter values, individualized for each BSS in a WLAN, that determine WLAN radio performance

Including, but not limited to:–BSS channel–AP transmit power–Client transmit power limit

November 2002

Richard Paine, Boeing

Slide 20

doc.: IEEE 802.11-02/651r0

Submission

What will radio measurements allow us to do?

–Simplify and/or automate WLAN radio configuration

–Achieve better performance in dense BSS deployments

–Better utilize radio resources across client stations

–Alert WLAN administrator to problems–Notify client station users of current radio status–Each company uses measurements to add value

November 2002

Richard Paine, Boeing

Slide 21

doc.: IEEE 802.11-02/651r0

Submission

What should we measure?

–Attributes that characterize the WLAN radio environment

–Attributes that affect or reflect WLAN radio performance

–Attributes that are not manufacturer specific

–Define the simplest, smallest set of measurements required

November 2002

Richard Paine, Boeing

Slide 22

doc.: IEEE 802.11-02/651r0

Submission

Two Categories of RM•Statistical Measurements characterize the radio environment in a long-term statistical sense. For example,– Measure 802.11 traffic load as channel busy fraction1

– Measure non-802.11 interference as received power histogram1

•Identity Measurements identify stations that affect each other’s performance. For example,– Identify each neighbor AP by overhearing its MAC address– Identify each neighbor STA and its serving AP in a similar manner– Identify hidden STA when receiving downlink frames with no ACK •1: these measurements are already in 802.11h draft

November 2002

Richard Paine, Boeing

Slide 23

doc.: IEEE 802.11-02/651r0

Submission

What changes are needed in all stas?

•Wireless MAC message protocol–Build upon 802.11h mechanisms and measurement frames–Add RRM capability bit and RRM action frame type–Augment 802.11h measurements with new

requests/reports•MAC firmware– Handle new management frames in the wireless MAC

protocol– Compute measurement payloads from PHY registers and

traffic

November 2002

Richard Paine, Boeing

Slide 24

doc.: IEEE 802.11-02/651r0

Submission

What additional changes are needed in access points?

•Process measurement requests from external entity–Translate external request into measurement action at AP

radio–Translate request into action frame and send to client

stations–Perform these actions at periodic interval, if requested•Accumulate, store and/or report measurements–Measurements taken at the AP radio–Measurements reported by client stations–Method of conveyance is a separate discussion

November 2002

Richard Paine, Boeing

Slide 25

doc.: IEEE 802.11-02/651r0

Submission

What should not change at any station?

–Wireless MAC control frames and procedures–Wireless MAC data frames and procedures–Any hardware, including MAC and PHY

November 2002

Richard Paine, Boeing

Slide 26

doc.: IEEE 802.11-02/651r0

Submission

Define Radio Control:

•What it is–Ability to remotely assign parameters values to client stations–802.11h already does something similar via Power Constraint–RRM could do this via parameter command action frames•What it is not–Algorithm for radio planning, load balancing or QoS control–Method for converting algorithm results into parameter values

November 2002

Richard Paine, Boeing

Slide 27

doc.: IEEE 802.11-02/651r0

Submission

The TGh model

• The 802.11 standard place MIBs in the MLME and PLME and specifies access from SME via the MLME SAP and PLME SAP using generic GET/SET primitives [see Figure 63 of ISO/IEC 8802-11:1999(E)]

• TGh handles measurement and control using MLME primitives.

November 2002

Richard Paine, Boeing

Slide 28

doc.: IEEE 802.11-02/651r0

Submission

TGh layer management model

• Extract from 802.11h-D2.1.32, which addresses some measurement extensions for DFS and TPC.

MAC Timing

MeasurementProcessing

MeasurementPolicy

Channel Switch Decision

MeasurementFrames

SME

MLME

Channel Switch Timing

PLME

SME

MLME

MREQUEST/MREPORT

MeasurementFrames

MeasurementPolicy

MEASURECHANNEL SWITCH

MREQUEST/MREPORT

Figure 26 – Layer Management Model

November 2002

Richard Paine, Boeing

Slide 29

doc.: IEEE 802.11-02/651r0

Submission

Maximum Amplitudes

Frequency (MHz)

Am

plid

ue (d

Bm

)

Future Allocation & Utilization

• Static Spectrum Management is Limited in Its Ability to Improve Spectrum Utilization Efficiencies

Fixed Spectrum Assignments Lead Fixed Spectrum Assignments Lead to Inefficient Spectrum Utilizationto Inefficient Spectrum Utilization– Opportunities Exist in Time, Opportunities Exist in Time,

Frequency, and GeographyFrequency, and GeographyRF Spectrum Allocated by PolicyRF Spectrum Allocated by Policy– Allocations, Assignments, and Allocations, Assignments, and

Incumbents Vary by CountryIncumbents Vary by Country

Heavy UseHeavy Use

Sparse UseSparse Use

Observations Show Bands of Local Observations Show Bands of Local Heavy and Sparse ActivityHeavy and Sparse Activity Temporal Usage Characteristics Temporal Usage Characteristics

Vary by Band & ServiceVary by Band & Service Potential for Usage Dependent on Potential for Usage Dependent on

Incumbent Service & EquipmentIncumbent Service & Equipment

Heavy UseHeavy Use

Medium UseMedium Use

November 2002

Richard Paine, Boeing

Slide 30

doc.: IEEE 802.11-02/651r0

Submission

What is the XG Program?

• Develop both the Enabling Technologies and System Concepts to Dynamically Utilize Spectrum– Improve Efficiency of Current, Static Assignments for Voice Improve Efficiency of Current, Static Assignments for Voice

and Data (Threshold: Factor of 10, Objective: Factor of 20)and Data (Threshold: Factor of 10, Objective: Factor of 20)– Provide Capability to Share Spectrum with disparate Provide Capability to Share Spectrum with disparate

systemssystems

RF emitters detect each other and adjust

automatically

XG Systems Will Opportunistically Utilize Unoccupied XG Systems Will Opportunistically Utilize Unoccupied Spectrum in Time, Space, and Frequency Spectrum in Time, Space, and Frequency

November 2002

Richard Paine, Boeing

Slide 31

doc.: IEEE 802.11-02/651r0

Submission

Key Technologies

•Develop Both the Enabling Technology and the System Concepts to Dynamically Use Spectrum

November 2002

Richard Paine, Boeing

Slide 32

doc.: IEEE 802.11-02/651r0

Submission

• Measurements Necessary for Future Growth

• Fast Track for Radio Resource Measurement

• More Control May Be Adopted as a Next Step (another task group)

• Future Technologies Require More Measurement

• Automating Radio Environment Adaptation

Conclusions