doc.: IEEE /1274r1 November 2011 Padam Kafle, Nokia Submission Neighboring Network Information Sharing through RLSS Authors: Date: Nov 7, 2011 NameCompanyAddressPhone Padam KafleNokia 6021 Connection Drive, Irving, TX, Mika KasslinNokia Itämerenkatu 11-13, Helsinki, Finland Prabodh VarshneyNokia 6021 Connection Drive, Irving, TX, Zhou LanNICT 3-4, Hikarino-oka, Yokosuka, Kanagawa, Japan, Hiroshi HaradaNICT 3-4, Hikarino-oka, Yokosuka, Kanagawa, Japan,

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 2 Contents Abstract Comments Discussion The OBSS Problem in TVWS Deployment Scenarios RLSS for Neighboring Network Information Sharing Network Coexistence through RLSS with Centralized Decision Summary

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 3 There are many comments asking to specify the coexistence mechanisms to avoid interference between overlapping BSS in TVWS band. This presentation discusses the problems and proposed solution from r3 to provide resolution for the following CIDs on coexistence: CIDs: 8, 500, 733 and 811. Abstract

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 4 Comments CIDClause Number(C) Page(C)Line(C)CommentProposed Change Need a mechanism for a portable BSS to detect presence of co-channel fixed devices so that it can move into a different channel. This is because there is a 16dB EIRP difference between the fixed and portable. So fixed APs may never detect a portable devices in the co-channel and thereby cause interference to the portable device BSS. Make transmission of unsolicited TPC report element mandatory for fixed TVWS devices. Also see 11/0265r0 for suggested text af15020The channel power management currently provides mechanisms for advertising available channels or changes to channel(s) or constrained maximum transmit power level(s). However, the problem of potential interference among multiple overlapping BSSs while operating on the allocated channel and transmit power levels are not taken in to account. Given the greater coverage range in TVWS band to more likely incur interferences, options for interference management among multiple overlapping networks should be specified in the specification. 733Generalthere is no specification for how the 5 and 10 MHz mode would coexist in a same TVWS channel, since the preambles cannot interoperate add detailed coexistence mechanisms

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 5 Comments.. CIDClause Number(C) Page(C)Line(C)CommentProposed Change 811General af is intended for increased range. However with that comes increased OBSS interference. Recommend studying interference mitigation schemes between OBSS

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 6 The larger cell coverage in TVWS band exacerbates the problem of overlapping BSS with hidden node STAs. In order to improve the utilization of limited available spectrum in TVWS band, enhanced coexistence mechanisms are required There are many possible scenarios for which, the legacy mechanisms currently available in (e.g. CSMA/CA, RTS/CTS etc) are not sufficient We had discussed some possible solutions in r1 during SFO meeting. This presentation is built upon the RLSS based approach, which had received good support from the straw poll: Do you support the use of RLSS to allow exchange of neighbourhood knowledge to address some of coexistence related comments? 7 Yes, 2 No, 5 Abstains Interference avoidance among multiple networks served by a common RLSS is considered here with two possible options for implementation: Distributed decision making Centralized decision making Discussion

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 7 There are two main problems: 1)When the transmit power levels in two overlapping BSS are significantly different (4 W Fixed vs 100 mW/40 mW Personal/Portable operation), the conventional RTS/CTS protection can not solve the interference from a hidden STA. The larger coverage range in TVWS makes it more difficult problem than in the legacy WLAN bands (limited channels but increased interference area) The OBSS Problem in TVWS

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 8 2.Overlapping BSS with different channel bandwidths will be common due to limited TV channels in many locations. One BSS with 5 MHz bandwidth may be adjacent with another using 10 MHz channel overlapping to it (refer to.11af channelization in next slide). However, OBSS scanning and coexistence notifications like in n can not work due to non-interoperable preambles The OBSS Problem in TVWS..

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 9 The OBSS Problem in TVWS.. Current channelization in.11af for US

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 10 Deployment Scenarios In many deployments, networks of different coverage range and capacity (e.g. low data rate coverage for parking lots/campus, and high-data rate indoor service) may be managed through a common RLSS Assumption: multiple APs are served by the same RLSS within one service provider’s domain, or AP from one SP’s network can request information from another AP with other SP’s network

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 11 A registered location secure server (RLSS) entity has been specified in current af specification: RLSS is an advertisement server to support RLQP using inter-working capability of u. RLSS can be implemented inside an AP or can reside outside It can provide the following functions for white space operation: proxy to external geo-location database a network management service node that facilitates the operational controls Once an AP (Mode II/Fixed) obtains the list of authorized frequencies and transmit power levels for the network initiation, additional information about other networks around its area becomes important for selection of its actual operational parameters (e.g. channel, bandwidth, power) How the RLSS can support/manage to avoid OBSS interference? Provide additional information about neighbouring networks to the APs. The decisions (network initiation or changes during operation) are local to the AP Control the operating parameters of the APs. The decisions on parameters are centralized to the RLSS Deployment Scenarios..

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 12 For setting up a network, an AP first obtains list of available channels at its location by performing channel availability query. It can then request additional Neighboring Network Information (NNI) from the RLSS for other networks in its neighbourhood served by the same RLSS NNI Query from a GDC AP to RLSS: Device ID, estimated maximum transmit power, geo-location (optional) Request Type: 0 for Neighboring Network Information Request values are reserved NNI Response from RLSS to the requesting AP: The response message contains current operational parameters of networks which are around the neighbourhood of the requesting STA (BSSID, used frequency channels, us ed channel widths, used transmit power levels, relative path losses, device classes) Neighboring Network Information through RLSS

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 13 How RLSS can provide the relevant information? From the known information about identity, device class and geo-location of each TVB D, RLSS internally determines the possible interfering networks in its service zone An exclusion zone may be calculated using the knowledge of available channels, and propag ation ranges of other BSS from the types of devices and their current transmit power levels Actual algorithms for deriving the information is implementation specific, and not spec ified by the standard After receiving the response for the NNI Query from RLSS, the AP can select its o perating frequency, channel width and transmit power to minimize interference to i tself, as well as, possible interference to its neighbouring networks What is required in.11af specification ? New RLQP elements to allow query and response messages for neighbouring network information Neighboring Network Information through RLSS..

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 14 RLQP ID LengthRequester STA Address Request Type Device Identification Estimated Maximum Transmit Power Device Location Information 1 octet 2 octets 6 octets1 octet18 octets1 octet18 octets (only if location is changed) Neighboring Network Information Response Neighboring Network Information Query  These fields are repeated as determined by the length field  RLQP ID LengthRequester STA Address Status Code BSSIDOperating Class Channel Number Device Class Operating Transmit Power Relative Path Loss 1 octet 2 octet6 octet1 octet 6 octets 1 octet Neighboring Network Information through RLSS..

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 15 Once an AP (Mode II or Fixed) obtains the list of authorized frequencies and tra nsmit power levels for the network initiation, it sends an NCC to RLSS to reque st a set of network channels The RLSS determines these set of channels based on information of neighboring APs to avoid coexistence problems Assumption: multiple APs are served by the same RLSS within one service provider’s domain and they use the network channels as determined by the RLS S Network Channel Control procedure in D1.04 can be already used (with some a dditional description on the usage) Network Coexistence through RLSS with Centralized Decision

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 16 The first message sent by the NCC requesting STA asserts identity and requests NCC. The NCC requesting STA may select its preferred frequencies from the WSM and reque st usage of the selected frequencies for multiple WLAN network channels usage. The NCC responding STA may grant permission of using the selected frequencies, or pr ovides its recommended set of frequencies, for multiple WLAN network channels to the NCC requesting STA by using the NCC response frame The recommendation of the NCC responding STA is based on the effort to minimize coexistence issue. The actual algorithm of deriving the recommended channels, however, will not be specified in af. RLQP Network Channel Control (NCC) request and response frame in Network Coexistence through RLSS with Centralized Decision..

doc.: IEEE /1274r1 November 2011 Submission Padam Kafle, Nokia Slide 17 The interference management among multiple BSS is more challenging in TVWS band due to larger coverage range Neighboring network information query through RLSS allows distributed decision making for APs RLSS shares the operating parameters of neighbours relevant for the requesting AP Each AP selects its operating parameters, but the network coexistence can be improved from the additional knowledge about other networks In addition, RLSS can also be used to enable centralized decision making for network coexistence management RLSS makes decisions for multiple APs for allocating operating parameters in order to resolve any coexistence problems Each AP uses NCC to obtain a set network channels as decided by the RLSS, so that all networks linked to the RLSS can coexist For flexibility in implementations,.11af should enable both of the above options Summary

doc.: IEEE /1274r1 November 2011 Padam Kafle, Nokia Submission Comments/Questions?