How do I get my cat to stop sitting on my bed at night?

I love my cat but at night I tend to move and she blocks me and I accidentally hit her and I hate doin that to her but my sister LOVES having her on her bed and whenever I move my cat to my sister's bed she jumps right back to mine. I don't mind having her on my bed during the day or at night when I'm not on my bed but I just don't like her there while I sleep. How can I keep my cat off my bed?