This paper proposes a modified sorted-QR decomposition algorithm for the high-dimensional multiple-input multipleoutput (MIMO) detection. Due to the growing demands of high-dimension MIMO channels and large number of OFDM subcarriers, the sorted-QR decomposition becomes one of the computational bottlenecks in the QR-based MIMO detection. The proposed Givens-Rotation-based algorithm aims to improve the throughput and the hardware utilization efficiency by relaxing the sorting condition and allowing the cross-column parallel rotation operations. The simulation results show that our proposed parallel algorithm can significantly reduce the minimal computation latency from 28% to 21% of the original algorithm, and the hardware utilization rate can be enhanced from 71% to 90% for 16×16 MIMO using four Given-Rotation processing elements. The detection performance degradation is negligible and better hardware efficiency can be obtained for the larger number of MIMO antennas.
I. INTRODUCTIONMultiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) technique has being developed in the next-generation mobile communication systems such as WiMAX IEEE802.16e [1] and 3GPP-LTE [2] standards. In order to improve the spectrum efficiency, more and more antennas are going to be employed, and thus higher transmission data rate can be obtained. Sorted-QR preprocessing in the MIMO detection algorithm is usually applied to optimize the channel processing order so that the better performance can be achieved [3][4]. One-time sorted-QR decomposition algorithm [5] is proposed to reduce the complexity but the performance gain is small. Therefore, the iterative QR-sorted decomposition algorithm is proposed to improve the BER performance. On the other hand, algorithmic, architectural, and arithmetic efforts [5][6][7][8] [9][10] are made to enhance the throughput or to improve the decomposition stability. However, limited study focuses on the parallel processing for the QR decomposition [11] . This paper aims to develop a computationally-efficient parallel QR decomposition algorithm for the high-dimension and high-throughput MIMO system.In this paper, we propose a modified sorted-QR decomposition algorithm for the MIMO detection. This algorithm is based on the Givens-Rotation QR decomposition algorithm. The sorting condition is modified by rearranging the rotation matrix multiplication on the parallel rotation processing elements (PE). This algorithm has better performance than