That is just the connection strength to your router - it has no bearing on your connection to the game unless you are only connecting to your own internal network to play it (which you are not). Even at 100% you can have interference on and off - it's simply the nature of wireless - it is a convenience technology, not a reliable one. Wired is the only way to effectively ensure you never have interference. What matters more is the UL/DL speed, PING/Latency, and packet loss coupled with your NAT ... these must be tested from your console to PSN or Bungie, not anywhere else, as that is the route the console is taking to the game. Also, if you are playing PvP (i.e. IB etc) then you have to be able to connect to all players on the same map equally. If any one of them have issues connecting to you or vise verse, then it can effect the whole match you are in. The only servers are the matchmaking ones - everything else relies on P2P hosting and networking

Game working just fine. Try rebooting your router.