Singular value decomposition-based multiuser multiple-input multiple-output vector perturbationaided downlink transmitter and lattice-reductionassisted uplink receiver pair

A full-duplex uplink/downlink (UL/DL) system having a UL transmitter/receiver (transceiver) pair and a DL transceiver is considered. Both the UL and DL are improved. The DL is enhanced by a novel vector perturbation (VP)-aided singular value decomposition (SVD)-based precoding scheme, which is capable of exploiting the different-quality SVD eigenbeams and substantially reduces the overall average transmit power requirement of the traditional zero-forcing (ZF) precoder. By contrast, the UL is enhanced by a lattice reduction (LR)-aided receiver scheme designed for SVD-based multiuser multiple-input multiple-output (MU MIMO) UL transmission, when different modulation schemes are employed for different-quality eigenbeams. This new UL scheme avoids the noise-enhancement problem of the classic ZF UL receiver. The authors demonstrate that the proposed VP-aided DL and LR-assisted UL constitute a powerful full-duplex system, which achieves an ~15~dB signal to noise ratio (SNR) gain for both SVD-based MU-MIMO DL and UL transmissions over the traditional ZF-aided schemes at a bit error rate (BER) of 10^-3.