Presentation on theme: "Doc.: IEEE 802.11-10/0544r0 May 2010 Padam Kafle, Nokia Submission Slide 1 Some Comments on White Space Map IE Authors: Date: May 14, 2010 NameCompanyAddressPhoneemail."— Presentation transcript:
doc.: IEEE 802.11-10/0544r0 May 2010 Padam Kafle, Nokia Submission Slide 1 Some Comments on White Space Map IE Authors: Date: May 14, 2010 NameCompanyAddressPhoneemail Padam KafleNokia 6021 Connection Drive, Irving, TX, 75039 +1 214 673 6232Padam.firstname.lastname@example.org Mika KasslinNokia Itämerenkatu 11-13, 00180 Helsinki, Finland +358-50-4836294Mika.email@example.com Naveen KakaniNokia 6021 Connection Drive, Irving, TX, 75039+1 214 763 1041Naveen.Kakani@nokia.com
doc.: IEEE 802.11-10/0544r0 May 2010 Padam Kafle, Nokia Submission Contents White Space Map IE proposal in 10/0472r1 –We want to understand what information are really useful/required? –Which frames should contain the information Can we reuse existing elements from 802.11 ? –AP Channel Report IE –Country IE Summary Slide 2
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 3 Introduction Main motivation for WSM in 10/0263r3 was to reduce scanning time for channels in TVWS –Proposed WSM for both passive scanning and active scanning –WSM announcement frame seems not for reducing the scan time We are not clear if the following fields are required or how they are useful: –TV bands database access time –Power constraint The main information (the list of channels) can be already provided by AP Channel Report IE –Use regulatory class for 5 MHz, center on center only –Use list of legal channel numbers If existing IEs can be used to carry the necessary information, we would like to reuse them
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 4 Clarifications on WSM IE TV bands database access time: –The main reason given in 10/0263r3 is to resolve situations when the STAs receive multiple beacons having WSM information from multiple APs, then the STA can utilize WSM with the most recent time stamp –When the database information is updated by the AP (as Master mode device) or through its enabling STA (for dependent AP), it will start using new WSM automatically. –If the information in AP is already older than 1 day (as per FCC’s rule), then it does not even need to transmit it (channel list is not valid any more legally) –When the distances of two APs are quite long, the WSM information itself can differ. Which information shall the STA even use? –Another reason given was when the WSM using more frequent DB access is provided, it can reduce sensing requirements The sensing requirements are in FCC rules, but under petitions If the intent is to get updated information within every 60 second for in-service monitoring, it applies only to the channel under operation. DSE procedure already has some mechanism in place
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 5 Clarifications on WSM IE.. Power constraint field for each channel: –Transmit power limits can be easily derived from the available channel list, for US domain (if occupied by primary user in adjacent channel, the transmit power level is low) –Any power constraint information for a dependent STA in an operating channel is available from DSE power constraint frame during DSE for the channel under operation Client STAs can transmit Probe Request frames in a TVWS channel only after they have completed DSE –The “power constraint” element in beacon can be also used (dot11SpectrumManagementRequired is true and optionally if dot11RadioMeasurementActivated is true) –One reason given was due to European regulations (e.g. Ofcom consultations), the information of transmit power level of each white space channel is required to be provided by database The rules are not yet clear If there will be different transmit power level requirements on different channels, will not it be already listed in Annex J?
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 6 Clarifications on WSM Announcement Frame WSM announcement frame contain WSM IE. The purpose of this frame is not clear from the associated text – is it meant to reduce scanning time? – is it for in-service monitoring based on this frame received every 60 s? – If there are multiple frames in same BSS, which information shall a STA use? Isn’t it so that each client only get channel information from its master? The current text: “ Whenever an enabling STA that has dot11TVWSMapEnabled set to true determines that the available TV channel list has been updated, the STA should transmit a correspondingly updated White Space Map Announcement frame” – does it means once the enabling STA accesses database for the information, then it has to transmit this frame? What if the enabling STA is an AP, why not it just send WSM in beacons? – An enabling STA is responsible to control only its client stations, why it is overburdened with announcing to all (over the air), and occupy the network resources/ Other questions: The text in 10/472r1, 11.1f1.1 says “Only enabling STAs may transmit enabling signals which contain WSM IEs which in turn allow dependent STAs to initiate networks in TVWS bands “. Based on.11y, the beacon frame containing “DSE Registered Location” element could have been an enabling signal. Does it mean “WSM” element alone in the beacon can work as an enabling signal? Slide 6
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 7 Reusing existing elements Other information in the WSM IE (the list of channels in a regulatory class) can be already provided by AP Channel Report IE –Use regulatory class for 5 MHz, center on center only –Use list of legal channel numbers (as specified by regulations) Other issues with WSM IE: –All available channels or subset of channels can be sent?
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 8 AP Channel Report AP Channel Report IE from 802.11k can be used –It can be present in Beacon, Probe Response frames –IE may be present if dot11RMAPChannelReportActivated is true. –one AP Channel Report element is present for each regulatory class that has at least 1 channel to report. Same IE can be used for other public action frames such as WSM Announcement frame proposed in 10/0472r1, if needed Element ID
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 9 AP Channel Report Current Text and Necessary Changes 22.214.171.124 AP Channel Report element(11k) The AP Channel Report element contains a list of channels where a STA is likely to find an AP. For operations in TVWS band, the element may contain the list of TV channels which are available for use. Element IDLength Octets: 1 1 1 variable Regulatory Class Channel List Regulatory Class contains an enumerated value from Annex J, specifying the regulatory cl ass in which the Channel List is valid. An AP Channel Report only reports channels for a si ngle regulatory class. Multiple AP Channel Report elements can be used to report channels in more than one regulatory class. The Channel List contains a variable number of octets, where each octet describes a single channel number. Channel numbering is dependent on Regulatory Class according to Annex J.
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 10 Other options Country IE ? –IE present if dot11MultiDomainCapabilityActivated is true or dot11SpectrumManagementRequired is true or dot11RadioMeasurementActivated is true. –can be present in Beacon, Probe Response frames Element ID Country Element Format
doc.: IEEE 802.11-10/0544r0 May 2010 Submission Padam Kafle, Nokia Slide 11 Summary We need more clarity to the actual need of information fields in WSM IE. If the essential and useful information about available TV channels can be already communicated using existing information elements from 802.11 spec, we would like to reuse them instead of defining new elements