Low complexity lattice reduction scheme for STBC two-user uplink MIMO systems

Abstract

Recently, a lattice reduction-aided (LRA) multiple-input multiple-output detection scheme has been proposed in junction with linear (as well as nonlinear) detectors. It is well known that these schemes provide a full diversity, and its complexity is comparable to that of linear detectors for the block fading channels. For the fast varying channels, however, the decoding complexity of LRA detection scheme is unreasonably high. This article proposes an efficient iterative lattice reduction (LR) scheme for an uplink system with two receive antennas at the base station and two users, each employing the Alamouti space-time block code (STBC). By taking advantage of the certain inherent STBC structure of transmitted symbols from users, the proposed scheme provides the same performance as a conventional LR while saving about 80% computational complexity. We also show that it can be successfully extended to handle the scenario where another interfering user, who is also employing the Alamouti STBC, is present.

Lattice-Reduction-Aided Detection with Successive Interference Cancelation for Multiuser Space-Time Block Coded Systems

“…In [8] the authors proposed two LRA detection algorithms based on QR detection, namely, SQRD and AQRD, and presented an implementation of the LRA detectors on programmable device for multiuser STBC systems. The authors of [9], however, proposed a method to reduce the complexity of the LRA detectors for multiuser STBC systems. Unfortunately, this proposal is applicable to a multiuser system with only two users.…”