Yes, I do own Battlefield 4 and the image in my signature is my BF4 stats.
512kbps is enough, but BSNL is not good enough unless you use
VPN with it. I get ~280ms without VPN and ~135 with VPN on Singapore servers. Also, make sure your connection does not have packet loss otherwise it'll lag. There are some servers which may kick for high ping(above 200ms), but you can just ignore those servers.