This is actually a problem I had at home. My Cisco Linksys E3000 wireless router had performed exemplary until about a month ago.
Though I hadn’t touched it, it started giving me ~500-1000ms latency and dropping packets; even when I was standing right beside it.
The solution was something I know I did with my old d-link routers aswell: setting fixed Channel Width for both the 2.4gHz and the 5gHz band. It defaults to Auto, and that’s not necessarily optimal.
Haven’t found any drawbacks to doing this so far, and all my units connect fine, with a latency of 2-4ms.
This will likely be worth trying regardless of router brand, if your router is acting up.