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New Radio Measurement Actions within the 802.11h Framework. Daryl Kaiser (Cisco Systems) 14 January 2003. Purpose. To review the radio measurement actions proposed in 02/677r2 To show how these measurements fit the 802.11h framework
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New Radio Measurement Actions within the 802.11h Framework Daryl Kaiser (Cisco Systems) 14 January 2003 Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems
802.11h defines an infrastructure for measurement requests and measurement reports • One or more Measurement Request elements per frame Measurement Request frame Measurement Report frame Element … Element Element … Element Params Params Params Params … Measurement Report frame Element … Element One or more Measurement Report elements per frame Params Params Daryl Kaiser, Cisco Systems
TGk would use the same measurement request format as 802.11h Add a category…and request/report actions • 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 Category Action DialogToken Activation Delay Measurement Offset One or moreMeasurement Request elements 1 1 1 1 1 variable Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems
TGk would use 802.11h Measurement Request Element ID and the same fixed field definitions • 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 Element ID Length Add measurement types 1 1 Measurement Token Measurement Request Mode Measurement Type Measurement Request 1 1 1 variable Daryl Kaiser, Cisco Systems
TGk measurement request details would include an extra field • 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 Channel Duration 802.11h measurement request details 1 2 Channel Scan Modeor Spare Duration TGk measurement request details 1 1 2 Daryl Kaiser, Cisco Systems
TGk would use the same measurement report format as 802.11h New category report action • 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 Category Action DialogToken One or moreMeasurement Report elements 1 1 1 variable Daryl Kaiser, Cisco Systems
TGk would use 802.11h Measurement Report Element ID and the same fixed field definitions • 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 Element ID Length New measurement types 1 1 Measurement Token Measurement Report Mode Measurement Type Measurement Report 1 1 1 variable Daryl Kaiser, Cisco Systems
Some TGk measurement report details would match 802.11h formats. Others would define new formats. For example, the new Beacon Report… • 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 Channel Duration PHY Type Received Signal Strength BSSID 1 1 1 1 6 Parent TSF Target TSF Beacon Interval Capability Information Received Elements 4 8 2 2 variable Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems
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 Daryl Kaiser, Cisco Systems