A method performed by a first unit of a base station system of a wireless communication network, for handling antenna signals for transmission over a transmission connection between the first unit and a second unit of the base station system, the base station system comprising a base unit and a remote unit, the remote unit being arranged to transmit the antenna signals wirelessly to, and receive from, one or more wireless communication devices, the antenna signals each comprising a plurality of IQ samples, wherein the first unit is the base unit and the second unit is the remote unit, or wherein the first unit is the remote unit and the second unit is the base unit, the method comprising: receiving IQ samples of a first antenna signal related to wireless communication of a first antenna of the remote unit, receiving IQ samples of a second antenna signal related to wireless communication of a second antenna of the remote unit; transforming the received IQ samples of the first antenna signal into transformed IQ samples, using a first transformation value; transforming the received IQ samples of the second antenna signal into transformed IQ samples, using a second transformation value, the second transformation value being different from the first transformation value; quantizing the transformed IQ samples of the first antenna signal using fewer bits than a first number of bits used for the received IQ samples of the first antenna signal; quantizing the transformed IQ samples of the second antenna signal using fewer bits than a second number of bits used for the received IQ samples of the second antenna signal, and transmitting the quantized and transformed IQ samples of the first and the second antenna signal over the transmission connection to the second unit for subsequent de-quantizing and re-transforming of the quantized and transformed IQ samples of the first and the second antenna signal into the received IQ samples at the second unit. receiving IQ samples of a first antenna signal related to wireless communication of a first antenna of the remote unit, receiving IQ samples of a second antenna signal related to wireless communication of a second antenna of the remote unit; transforming the received IQ samples of the first antenna signal into transformed IQ samples, using a first transformation value; transforming the received IQ samples of the second antenna signal into transformed IQ samples, using a second transformation value, the second transformation value being different from the first transformation value; quantizing the transformed IQ samples of the first antenna signal using fewer bits than a first number of bits used for the received IQ samples of the first antenna signal; quantizing the transformed IQ samples of the second antenna signal using fewer bits than a second number of bits used for the received IQ samples of the second antenna signal, and transmitting the quantized and transformed IQ samples of the first and the second antenna signal over the transmission connection to the second unit for subsequent de-quantizing and re-transforming of the quantized and transformed IQ samples of the first and the second antenna signal into the received IQ samples at the second unit.