Optimal zero-forcing transceiver design for maximizing bit rate subject to a total transmit power constraint

In this paper, we design the optimal zero-forcing transceiver that maximizes the transmission bit rate for multiple-input multiple-output (MIMO) channels. The transmission bit rate is maximized subject to a total power constraint for a given error rate. Instead of using the same input constellation size for all subchannels as in earlier designs, the bit allocation is also taken into consideration. The bit allocation and the zero-forcing transceiver are jointly designed for bit rate maximization. The optimal transceiver is obtained in a closed form. The bits are allocated according to the subchannel signal to noise ratios. The larger the signal to noise ratio is, the more the number of bits are allocated. In the simulation, we have demonstrated that a higher bit rate can be achieved compared to previously reported methods.