Sunspot cycle is 11 years, not 7.
The frequency of solar flares are linked to sunspot activity, and it is flares that are important here. Problems occur when charged particles from a solar flare (specifically Coronal Mass Ejections) interact with the Earth's magnetosphere. This causes fluctuations in the magnetic field of the Earth, and a fluctuating magnetic field can induce electrical currents (this is just how your Magneto works
). The magnitude of the induced current depends on the size of closed loops in an electrical system, and so in very large systems problems can occur - the classic example being the Quebec Electricity Grid in 1989.
I see no obvious reason that this would be a concern in a Wireless LAN - any arial will be far too small - but if you can think of a reason why you might have a problem then hire an expert.