On Tue, Nov 17, 2009 at 3:39 PM, Tom Sharples <tsharples@xxxxxxxxxx> wrote: > >> >>> There are several miniPCI >>> based radios that require half or quarter width channels on some >>> channels. >> >> That *require* this? >> >>> For example, the Ubiquiti XR7 requires quarter width channels on two of >>> its >>> four available channels. >> >> Regulatory wise? What's the restriction based on? >> >>> The XR9 requires half width channels on two if its >>> four available channels. >> >> Same here, what's the restriction based on? >> > On 900 and the 4.9 Ghz public safety bands, the half or quarter channels are > required if you want to: > > (a) Support multiple non-overlapping links within the legally allocated > bandwidth. For example, within 900 Mhz there is only 25 Mhz total available, > and only two 20-mhz channels defined (which, of course, overlap) so really > you've only got one. With 5 Mhz channels, you can operate legally near the > edge of the band without interfering with other 900 Mhz links, or > transmitting outside of the FCC allocated band. > > (b) Operate legally and efficiently in the 4.9 Ghz public-safety band. The > upper and lower three channels defined by the FCC are 5Mhz and 10Mhz. 20 Mhz > operation there would violate the allocated band edges. > > (b) Be compatible with other company's products that use these channels, > e.g. Proxim, Cisco, Ubiquiti, etc. > > On 2.4 and 5.8 half and quarter aren't a legal requirement, but they > certainly are necessary for efficient operation! It sounds like we can support all of this regulatory-wise. All that's needed then would just be the cfg80211 stuff. You'd just define a custom regulatory domain for public safety, and have a card programmed on the EEPROM for it. OK next question -- who does the regulatory testing for these cards? I don't think Atheros does. I know Atheros doesn't do regulatory testing for APs -- the AP manufacturer ends up doing the testing. Atheros only does regulatory testing for stations. This sounds like the supplier/manufacturer of these devices capable of operating for public safety would have to be the one testing. Please let me know. Only reason why this is important is they'd end up being the ones supplying a regulatory.bin. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
