A GPU Implementation for two MIMO-OFDM Sphere Detectors

Teemu Nyländen1,  Janne Janhunen2,  Olli Silvén1,  Markku Juntti2
1Information Processing Laboratory, University of Oulu, 2Centre for Wireless Communications, University of Oulu


Abstract

Two real-valued signal models based on selective spanning with fast enumeration (SSFE) and layered orthogonal lattice detector (LORD) algorithms are implemented on Nvidia graphics processing unit (GPU). A 2×2 multiple-input multiple-output (MIMO) antenna system with 16-quadrature amplitude modulation (16-QAM) is assumed. The chosen level update vector for SSFE is based on the computer simulation results carried out in MATLAB environment. We implemented the algorithms with Nvidia Quadro FX 1700 GPU and achieved a detection rate of 36.06 Mbps for SSFE and 17.95 Mbps for LORD. The results show that the general-purpose graphics processing unit (GPGPU) has potential to achieve high detection rate, presuming a detection algorithm that allows efficient parallel processing. The latency of the control code and partial Euclidean distance (PED) calculations are very small-scale, but the latency of memory loads and stores to the GPUs global memory are significant. We will also compare results from the trellis based detector implementation for GPU, where a more powerful GPU and a different detection algorithm are used. The GPUs offer superior computing power and programmability compared to the application specific software defined radio (SDR) designs implemented so far.