MIMO Broadcast DFE Transceivers With QoS Constraints: Min-Power and Max-Rate Solutions

This paper considers two joint design problems of linear precoder, decision feedback equalizer (DFE) and bit allocation for multi-input multi-output (MIMO) broadcast (BC) channels. The first problem is a power minimization problem (min-power) with a total bitrate constraint and per data stream symbol error rate (SER) specifications. The second problem is a rate maximization problem (max-rate) with a total transmit power constraint and per data stream SER specifications. For a given broadcast DFE transceiver, optimal bit allocation formulas for both problems are derived. A particular class of joint triangularization (JT) is applied to obtain the optimal broadcast DFE transceivers for the min-power and max-rate QoS problems, namely the minimum power JT broadcast DFE transceiver (MPJT) and the maximum rate JT broadcast DFE transceiver (MRJT), respectively. Two suboptimal broadcast DFE transceivers, the power minimized QR broadcast DFE transceiver (PMQR) and the rate maximized QR broadcast DFE transceiver (RMQR), are also proposed for the min-power and max-rate QoS problems, respectively. The proposed suboptimal designs apply QR decompositions instead of the particular class of JT. Moreover, integer bit allocation problems for both QoS problems are addressed. This work also shows the duality of the proposed MPJT and MRJT transceivers. At the end, numerical results are presented to demonstrate the performance of the proposed MPJT, MRJT, PMQR and RMQR transceivers under different QoS constraints, and verify the duality of the proposed MPJT and MRJT transceivers.