associated with one UE-specific reference signal is also available. This antenna port can be used for conventional beamforming, especially in the case of TDD operation. All physical layer processing (i.e., up to and including the scrambling module) for the nth transport block in a certain subframe is denoted by codeword n. Up to two transport blocks can be transmitted simultaneously, while up to Q = 4 layers can be transmitted for the rank-4 case, SO there is a need to map the codewords (transport blocks) to the appropriate layer. The layers form a sequence of Q X 1 symbol vectors as Sn (Sn1, Sn2, ,SnQ)t which are input to a precoder that in general can be modeled on the form of a linear dispersion encoder. The precoder only exists if the PDSCH is configured to use cell-specific reference signals, which are then added after the precoding and thus do not undergo any precoding. If the PDSCH is configured to use the UE-specific reference signals, which would then also undergo the same precoding operation as the resource elements for data, then the precoder oper- ation is transparent to the standard and therefore purely an eNB implementation issue. The precoder is block-based and outputs a block Xn = XnL+L-1) of precoded N X 1 vectors for every symbol vector Sn where L is the block size and the parameter N denotes the number of antenna ports, if PDSCH is configured to use cell-specific reference signals. If a transmission mode using UE-specific reference signals is configured, then, similarly to above, N is entirely up to the eNB implementation, but it typically corresponds to the number of transmit antennas assumed in the baseband implementation. The vectors Xk are distributed over the grid of data resource elements belonging to the resource block assignment for the PDSCH. Let k denote the resource element index, the corresponding received N X 1 vector on the UE side after DFT operation can then be written as =HHX + Wk where Hk is an N X N matrix that represents the MIMO channel and Wk is an Nr X 1 vector denoting n