A transmission apparatus and method, respectively, mapping payload data of mapping input data streams onto a mapping output data stream having a channel bandwidth for transmission in a multi-carrier broadcast system. To enable selection of robustness for transmission of data, the apparatus includes a frame forming mechanism mapping data blocks of at least two mapping input data streams onto frames of the mapping output data stream covering the channel bandwidth, each frame including a payload portion, the payload portion including plural data symbols and being segmented into data segments each covering a bandwidth portion of the channel bandwidth. The frame forming mechanism is configured to map the data blocks of the at least two mapping input data streams onto data symbols of the payload portion and includes a MIMO mode selector selecting a MIMO mode of the data blocks per data segment and/or per mapping input data stream.