Good afternoon, Hasan (and Geoff) Appendix e does discuss a number of mitigation factors designed into 802.15.4 to improve its ability to coexist with other 802 as well as a narrow class of known interferers. Two important features are the non-alignment of of 802.11 channels with that of 802.15.4 channels in the 2400MHz band. This in theory allows an 802.15.4 station to operate away from a given 802.11 station in the immediate vicinity and even provides (in many regulatory domains) a few 15.4 channels that are completely clear of 802.11 channels. The other is the temporal agility of the 15.4 radio and the brevity of conversations (low duty cycle)- the fact that clear channel assessment and an entire 802.15.4 conversation (data transmission and acknowledgement) can occur in a few milliseconds. This means that 802.15.4 transceivers can take advantage of small gaps in conversations taking place between 802.11 equipment, the off times for consumer microwave ovens, etc.
There is a real issue with 802.11n in 40MHz channels, one that was not perceived long ago. As it is described right now, the expectation by a number of 802.11 voters is to allow 2 channels of non-overlapping 40MHz-wide operation in the US 2400-2483.5MHz band (and likely in other regions/countries as well). If there is agreement on this, there will be locations (likely many) where both 40MHz channels are occupied and used intensively. With two heavily loaded 11n channels and a number of hidden transmitters, it may prove difficult for 802.15.4 stations to compete successfully as there will be NO clear channels and only the temporal agility of the 15.4 radio gives it a chance to communicate. Sincerely, Jon Jon Adams Business Development, Wireless Connectivity Operation Freescale Semiconductor 2100 E Elliot Rd MD EL 542 Tempe, AZ 85284 +1 480.628.6686 mobile +1 480.413.3439 office [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Geoff Mulligan Sent: Monday, July 07, 2008 8:31 AM To: Mustafa Hasan Cc: [email protected] Subject: Re: [6lowpan] Regarding coexistence with 802.11n Appendix E of the 802.15.4 standard goes into detail on co-existence. On Fri, 2008-07-04 at 09:04 -0700, Mustafa Hasan wrote: > Dear 6lowpaner, > > I need little help regarding the coexistence issue of ISM Band with > other ISM, especially with the 802.11n, 802.11b. > > I want to know what are the factor is going to save the 802.15.4 > fighting with others frequency. > > > Thanks in Advance... > > > Regards > > M. Hasan > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
