On the Robustness of Lattice Reduction Over Correlated Fading Channels

In multiple-input multiple-output (MIMO) systems, the use of lattice reduction methods significantly improves the performance of suboptimal algorithms. Taking advantage of the temporal correlation of a Rayleigh fading MIMO channel, the robustness of lattice reduction is investigated in this work by adaptively updating the reduced lattice basis. It is shown that by using the result of the previous channel realization, we can achieve the same error performance as the original lattice reduction, but with lower computational complexity. Another method is also considered for lattice reduction that further reduces the complexity at the cost of a degradation in the error performance by employing a measure that offers an appropriate tradeoff. These adaptive methods can be used in conjugation with any lattice reduction algorithm and in any MIMO scenario over correlated channels that requires lattice reduction, such as the MIMO detection and broadcast systems.