We don’t think about it like that on a daily basis, but WiFi has G’s too! WiFi has Generations as it has evolved and new standards and specs have been released by the IEEE Standards Association process. WiFi is actually at a higher number than Cellular since it is at 5G – 5th Generation. But people don’t talk about WiFi as being 4G or 5G – they talk about it using the “802.11” specification number and lettering system. The latest one released and in wide use now is 802.11ac. The one before that was 802.11n.
Most marina Hotspots probably won’t be sporting an 802.11ac signal, and maybe not even an 802.11n signal. I think the problem is the faster speeds could easily saturate their Internet backhaul connection if they went faster than 802.11G. Think about it – a Fast landline based connection now is around 50 Mb/s. It wouldn’t be hard to saturate that if one or more boats could do 50 or 100 Mb/s through their Hotspot system.
Anyway I was looking for something online that had a description or even better some graphical representation of the Generations of WiFi. I thought it would be interesting to me and possibly others. I found this:
I won’t steal their chart of the WiFi Generations … so you can go look at it on there. It is also helpful to have a look at Wikipedia for more information on the WiFi technologies.
Interestingly the 802.11ac is only in the 5Ghz frequency band, whereas 802.11n was in both 2.4 Ghz and 5 Ghz bands. Where this relates to marine installations for Hotspot access it affects the antenna situation. A 2.4 Ghz WiFi antenna is not made to work on the 5 Ghz band obviously. Also the newer generations of WiFi are more and more wanting to use multiple antennas. Which means if there were Hotspots that provided it – you would really need two or more antennas on your boat to fully use the specifications. This is similar to what is happening in the G’s in Cellular. From 3G to 4G LTE in cellular – more and more they are wanting to TALK to you on 2 or more antennas to deliver not only special diversity (antenna diversity) but to actually deliver more speed by sending more than one signal – more than one data stream to your device.
When it comes down to routers on marine vessels we have to start thinking about these things … because that’s how these technologies work. The antennas don’t have to be THAT far apart. Think of how far apart they are in a smart phone or a tablet computer?
* Anyway even if marinas are providing 802.11n and 802.11ac – it is possible to do this from a boat router (client of a Hot Spot) with 1 antenna. In “N” you can do this with a 2.4 Ghz antenna … for “AC” you would need a dual band 2.4 / 5 Ghz antenna. Supposedly in “N” this is about 150 Mb/s max (nobody else using it theoretical max?) and with “AC” in 5 Ghz this is 433 Mb/s max (again nobody else using it theoretical max?)
Now it is interesting for inside of a marine vessel to use faster speeds – in case you want to wirelessly access media like video … but again for the Hotspot external WiFi access – I doubt anybody is going to let you go 100 Mb/s or more on their Internet backbone connection for FREE. If they would allow that at all.
Also 802.11 WiFi in 2.4 Ghz had a non-overlapping channel problem where only 3 of 11 channels was really available where other AP / Client systems were within range. It seems like 5 Ghz is having a similar problem – perhaps even worse because of larger Mhz bandwidth usage in the protocols.
“The 5 GHz band, however, has 24 non-overlapping 20 MHz wide channels in North America (19 elsewhere). But due to possible interference with radar systems, only the bottom four and top five channels are commonly used by consumer Wi-Fi gear. The channels marked DFS required in the table below require a technology known as Dynamic Frequency Selection, which is usually implemented along with Transmit Power Control (TPC).”
* You can quickly see that 24 channels @ 20 Mhz gets cut in half with 40 Mhz channel bandwidth usage, and in half again when 80 Mhz channel bandwidth is used. And this includes the radar interference potential channels requiring DFS. The channels are actually 5 Mhz apart … nobody does that … even double that at 10 Mhz … nobody does that. Double again now here is where systems in reality use it with 20 Mhz spacing. But if someone nearby uses 40 Mhz or 80 Mhz you can see how you can get clobbered. So how do you do an outdoor 5 Ghz implementation?
That’s all for now …
Alan Spicer Marine Telecom
+1 954 683 3426
communications @ marinetelecom.net