Downlink transmission scheme 367 supported for the LTE downlink includes QPSK, 16QAM, and 64QAM, cor- responding to two, four, and six bits per modulation symbol, respectively. All these modulation schemes are applicable to the DL-SCH, PCH, and MCH trans- port channels. As will be described in Chapter 18, only QPSK modulation can be applied to the BCH transport channel. 16.5.7 Antenna mapping The Antenna Mapping jointly processes the modulation symbols corresponding to, in the general case, two transport blocks, and maps the result to the different antenna ports. As can be seen from Figure 16.26, LTE supports up to four trans- mit antenna ports. The antenna mapping can be configured in different ways to provide different multi-antenna schemes including transmit diversity and spatial multiplexing. More details about the antenna mapping and, in general, about LTE downlink multi-antenna transmission, are provided in Section 16.6. 16.5.8 Resource-block mapping