I'm not sure if this is simple or not; if not then the solution is almost certainly going to use a Linux box so this might be on topic, but if not I can't think who else to ask.
In my office I have a Draytek router, connected to ADSL (was O2, now Sky), with it's WAN port connected to another ADSL router, itself connected to PlusNet, and load balancing between the two. I have it set up this way due to the pretty useless speeds we get here (I just ran a speed test and got 3Mbps up, 0.5Mpbs down). No prospect of it changing much either in the short term.
On the other hand, the same speed test on my phone shows 20Mbps down, 8Mpbs up (4G on Three). And I have free unlimited data including tethering.
So I want to find a way to tether my office network onto my phone when I'm in the office.
Is this just as simple as replacing the second ADSL router with an access point, or do I need to be more clever than that? (Also: the Draytek has a USB port for (eg) a USB 4G dongle, but could I use a USB wifi dongle to tether to my phone instead?)
The "right" solution is to get a 4G dongle for the Draytek, but data plans on data SIMs don't seem all that great - and even phone contracts aren't as good as they were (I get unlimited tethering, but new contracts limit to 5GB while tethering). So I'd like to find a way to use my existing phone connection if I can, albeit that it's going to kill my battery when I use it. Although if anyone can point at decent 4G data plans instead I'd be happy to switch (I am already paying for two ADSL lines so I can ditch one of those if I get this working).
(Apologies to anyone who would kill for the 3Mbps I currently get!)
Mark