Study on modulo-lattice in vector perturbation for MIMO broadcast channels

Abstract

The modulo in the vector perturbation for the multiple-input multiple-output broadcast channel is studied. The notion of modulo-lattice is presented, which is a direct extension of the conventional modulo constant. And the conditions that a good modulo-lattice should be satisfied are analyzed. Based on this analysis, some good modulo-lattices are suggested for the quadrature-amplitude modulation (QAM) and the phase-shift keying (PSK), respectively. For example, a scale hexagonal lattice is suggested as the modulo-lattice for M-PSK (M>4). Moreover, the efficient implementation of the modulo-lattice at the transceiver is illustrated by the scale hexagonal lattice. Simulations show that the modulo-lattice suggested has a gain of about 0.8 dB over the conventional modulo constant in high signal-to-noise ratio (SNR) regions for M-PSK.