Efficient Implementation of Successive Encoding Schemes for the MIMO OFDM Broadcast Channel

In the work at hand relevant issues concerning implementation of optimal and nearly optimal transmission approaches for the MIMO OFDM broadcast channel are discussed. In particular, algorithms proposed to compute optimum covariance matrices are efficiently extended to the multicarrier setting. Furthermore, a method is proposed to transform the resulting vector channels into a set of scalar subchannels over which information can be independently transmitted without incurring any capacity loss. This effective diagonalization of the broadcast channel is most convenient for practical purposes as, so far, existing techniques for coding with side information have exclusively been conceived for scalar subchannels. Finally, we discuss the practical advantages of a suboptimum technique such as the cooperative zero-forcing with successive encoding and successive allocation method (CZF-SESAM). This technique exhibits a nearly optimum performance and significantly simplifies both computation of transmit covariance matrices and downlink signaling.