Wireless Signal Degrades over Time

[Photonicsia]

I am running PFS 1.2.3, Loadbalancing 3 WAN connections (1 Wired 2 Wireless ) The problem is The wireless signal strength starts out at 54Mbps and slowly over about a 2 hour time period works down to 1Mbps. Under interfaces I release and renew and the signal strength comes back.

Is there anyway to automatically have these connections renew themselves on a timed basis to maintain optimal network speeds?

Thanks