3 ms·

> time and space are also important dimensions Unfortunately they are harder to control. My apartment is surrounded by other apartments also transmitting on a

> time and space are also important dimensions Unfortunately they are harder to control. My apartment is surrounded by other apartments also transmitting on a polluted spectrum and I can't control when or where they transmit. I also can't control the age or transmitting speed of their devices. Simply opening up more spectrum is a net benefit to both me and them.

freyir 10y ago
> I can't control when or where they transmit. You can't actually control which frequencies your neighbors transmit on either. The best you can do is observe which frequencies are the most crowded, and avoid them. But essentially this is what happens in the time dimension as well. Wi-Fi devices share a the channel across time using a technique called Carrier Sense Multiple Access (CSMA). When a device has something to send, it observes the channel to see if anybody else is transmitting, and if not, it waits a short random back-off time and then transmits. All devices are doing this, and since the back-off time is randomized, it's more or less fair.
- jordanthoms 10y ago
  Unfortunately that only works if the other APs are using the exact same channel, rather than an adjacent-but-overlapping one. It'd be great if consumer routers would only allow use of channel 1, 6, or 11, to avoid the usual situation where there is APs on every single channel interfering with each other rather than co-operating.
  - ryao 10y ago
    I have a neighbor on channel 5. I have thought of discussing it with them, but being across the street, the signals are so weak that I am not sure if interference is possible.
    - rincebrain 10y ago
      Possible, yes. Impactful, probably not.
  - rahimnathwani 10y ago
    So if I have neighbours all channels except channel 7, am I better off choosing channel 6 or 8, than I would be if I chose the 'empty' channel 7?
  - Bromskloss 10y ago
    Why are there overlapping channels in the first place?

freyir 10y ago

> I can't control when or where they transmit. You can't actually control which frequencies your neighbors transmit on either. The best you can do is observe which frequencies are the most crowded, and avoid them. But essentially this is what happens in the time dimension as well. Wi-Fi devices share a the channel across time using a technique called Carrier Sense Multiple Access (CSMA). When a device has something to send, it observes the channel to see if anybody else is transmitting, and if not, it waits a short random back-off time and then transmits. All devices are doing this, and since the back-off time is randomized, it's more or less fair.

jordanthoms 10y ago
Unfortunately that only works if the other APs are using the exact same channel, rather than an adjacent-but-overlapping one. It'd be great if consumer routers would only allow use of channel 1, 6, or 11, to avoid the usual situation where there is APs on every single channel interfering with each other rather than co-operating.
- ryao 10y ago
  I have a neighbor on channel 5. I have thought of discussing it with them, but being across the street, the signals are so weak that I am not sure if interference is possible.
  - rincebrain 10y ago
    Possible, yes. Impactful, probably not.
- rahimnathwani 10y ago
  So if I have neighbours all channels except channel 7, am I better off choosing channel 6 or 8, than I would be if I chose the 'empty' channel 7?
- Bromskloss 10y ago
  Why are there overlapping channels in the first place?