I have a similar situation, although it's not really a problem as my older cat is coping well with the new kitten - he seems to enjoy playing with him most of the time and he always wins the 'fights' as he's twice the size and weighs about 3 times as much
He does sometimes get a bit fed up with always being pounced on though (and having his tail pulled especially) and gives kitty a hiss and a growl for being so impudent. I just try to distract the kitten with toys and games so that Jaffa can have a time out and it works pretty well. It's in their nature for kittens to want to play with everything that moves! Time will help solve this problem if you can manage the situation in the meantime and give your older cat a bit of a breather from time to time. Perhaps you can set aside a room which only your older cat is allowed to use? She then has somewhere she can go to get away from your kitten. If it gets really bad you might just have to separate them until your kitten is a bit older.