There should be a 6 week notice period. This does happen at the start of the season but after Christmas, due to Europe, cup replays and Sky / BT Sport deciding what games are worthy of a TV slot.
The TV companies should also take into account the travelling involved for away fans when scheduling games and also the price of tickets. Tv companies should be subsidising ticket prices / travel costs for games rescheduled at short notice.
The match going fan is the one who pays the heaviest price as the armchair fan benefits. Problem is without fans in the stadium the TV companies don't a product that looks good on TV. TV companies need to help not hinder attendances at games.