Need For Most Wanted PS Vita multiplayer lag

I have Most Wanted for my Vita and although i have good connection the multiplayer lags a lot.A friend of mine who has nearly the same connection as me plays multiplayer on its Vita without serious lag(i mean that there is always a bit lag but for him it doesn't affect the fun he has when playing it).He lives in England and i live in Greece.Every time before i play i activate the 'game' option from the Playstation Network Settings.It doesn't affect anything.Please help!