A method includes generating automatic repeat request feedback information at a first device in response to a downlink transmission from a second device; encoding the feedback information to comprise an indication of a number of streams received in the downlink transmission and transmitting encoded feedback information to the second device. Another method includes transmitting a multi-stream downlink transmission from a first device to a second device; receiving encoded hybrid automatic repeat request feedback information from the second device; decoding the received hybrid automatic repeat request feedback information at the first device; and determining from the encoding of the hybrid automatic repeat request feedback information at least a number of streams that were actually received by the device from the downlink transmission. A wireless link between the devices can be a 2×2 MIMO link. Also disclosed are memory mediums for storing program instructions to implement the methods, and apparatus including user equipment and base stations constructed to carry out the methods.