Hybrid guided search detector for MIMO systems

In multiple-input-multiple-output (MIMO) systems, there is a performance degradation using conventional detector (CD) due to the combined effects of the signal interference between antennas and the possible correlation between the received fading signals. Thus, the matched filter in each received antenna becomes inefficient in high data throughput demanding systems. The performance or system capacity under conventional detection will be substantially degraded when the spatial diversity provided by multiple antennas can not be fully exploited and the detection process is unable to efficiently separate the signal from each antenna. The solution discussed in this paper seeks to establish more efficient detectors for MIMO systems. These detectors use information from the interfering signals in a way to improve the signal detection in the antenna of interest, thus providing advantages over the conventional system, at the expense of increasing complexity. The focus of this paper consists in proposing a hybrid guided search MIMO detector utilizing the main advantages of two representative sub-optimal detectors based on the maximum-likelihood function and the guided search principle, the Sphere Detector (SD) and the QR decomposition with M algorithm based (QRD-M).