doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 1 Operation rules for > 40MHz Bandwidth Date: Authors:

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 2 Abstract The presentation discusses how to operate in a scenario where a tertiary or quaternary channel of a BSS overlaps with the primary channel of another BSS?

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 3 Targets of Operation Rules Targets of the channel operation rules in ac: –Simplify and speed-up the discovery and scanning operations –Simplify the frequency use –Enable efficient resource use –Avoid introducing new type of “hidden terminal” problems

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 4 Channelization of ac Channelization is taken from r13: –The 20/40/80MHz transmissions may be performed in IEEE channels as shown below

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 5 Question for Channels Operation Rules May a BSS use its tertiary or quaternary channel (20MHz) when it discovers an overlap with the primary channel (20MHz) of another BSS? Lets compare two alternatives: –“NO”: Tertiary and quaternary channel shall not be used at IEEE channel that contains primary channel of another BSS Justification: n rule restricts BSS to use its secondary channel at a channel that has primary channel –Following the same logic, the tertiary and quaternary channels use is restricted in IEEE channel containing primary channel –“YES”: Tertiary and quaternary channel may operate at IEEE channel that contains primary channel of the other BSS Justification: n does not define primary channel operation in channel containing tertiary or quaternary channels

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 6 Features of the Channel Operation Rules Alternatives “NO” The NAV and CCA protection of the primary channel are available for all (prim,sec,ter,quar) channels Primary channel of another BSS can possibly overlap the secondary channel and this can limit the transmission bandwidth to 20 MHz Primary channel of another BSS in tertiary or quaternary channel limits the transmission bandwidth to 40 MHz “YES” Only the CCA protection is available when primary co-exists at the same channel as (sec,ter,quar) channel of another BSS The STA may aggressively use the IEEE channels in which other BSSs primary channels operate, no transmission bandwidth limitations –Possible to use the full 80 MHz

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 7 Performance of Channel Operation Rules Alternatives Throughput of “NO”: –Light traffic All traffic is transmitted Depending on the traffic model, TX time may be little longer than in “YES” –Moderate traffic In uneven traffic load, the high load BSSs may use at maximum 40 MHz bandwidth –High traffic At maximum one BSS may use 40 MHz bandwidth Some small degradation due to CSMA/CA collisions of traditional hidden terminals may occur Throughput of “YES”: –Light traffic All traffic is transmitted Depending on the traffic model, the TX time may be little shorter than in “NO” –Moderate traffic The lack of NAV causes collisions and lowers throughput In unevenly loaded BSSs, the BSS may benefit from higher bandwidth –High Traffic All BSS try to use the whole 80 MHz bandwidth, high variation in throughput may occur High amount of retransmissions due lack of NAV protection lowers throughput Severe hidden terminal problems

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 8 Strawpoll 1 Are you in favour of: –“NO”. Tertiary and quaternary channel shall not operate at IEEE channel that contains primary channel of the other BSS: –“YES”. Tertiary and quaternary channel may operate at IEEE channel that contains primary channel of the other BSS:

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 9 Strawpoll 2 Should all transmissions be protected with CCA and NAV: –Yes –No

doc.: IEEE /1149r0 Submission September 2010 Jarkko Kneckt, Nokia CorporationSlide 10 References r13