My bb has the same problem during 0 - 10 months. bb is only 淺睡 at the first 30 mins, not yet going to the stage of 熟睡.
BB also needs 安全感, When you put bb onto her ownbed, let her head lean against the headboard or place your cloth near so that she can smell this familiar smell.
When the weather is cool, BB would wake up more easily and frequently. I put a 暖水袋 on her bed.