The embodiments herein relate to a method in a transmitter (101) for transmitting at least a first data burst and a second data burst to a receiver (105) in a system (100) applying applies closed loop codebook-based precoding MIMO. The transmitter (101) comprises at least a first Tx antenna (107a) and a second Tx antenna (107b). The transmitter (101) transmits, to the receiver (105), at least the first data burst through the first Tx antenna (107a) and the second data burst through the second Tx antenna (107b). The first data burst comprises a first training sequence and the second data burst comprises a second training sequence when the first data burst and the second data burst are non-precoded. The first data burst comprises a third training sequence and the second data burst comprises a fourth training sequence when the first data burst and the second data burst are precoded.