| Summary: | 碩士 === 國立中央大學 === 電機工程學系 === 101 === Precoder Selection Under MIMO Detection
for 3GPP-LTE/LTE-A Systems
Abstract
Precoding by using a finite-set codebook at transmitters is an effective approach to
improve the performance of multiple-input multiple-output (MIMO) systems with reduced
feedback overhead. K-Best sphere decoders are popular for high-throughput
spatially-multiplexed MIMO signal detection at receivers.
In this paper, we propose a precoding-matrix-index (PMI) selection criterion suitable for
K-best MIMO detectors by minimizing the trace of the upper triangular matrix after QR
decomposition (QRD). To further improve the system performance, fully-sorted QRD,
per-layer sorted QRD and partially-sorted QRD are also proposed to be incorporated in the
minimum-trace PMI selection criterion. Simulation results based on the MIMO codebooks of
3GPP-LTE/LTE-A systems show the improvements of the proposed scheme compared to the
non-precoding MIMO schemes and the precoding schemes using the conventional PMI
selection criterions.
Considering the fading channel in time/frequency domain of LTE system, we propose a
group solution, which not only provide much lower computation, but also avoid more
degradating.
As to the hardware implementation, we use a scalable design of high throughput 8×8
Sorted QRD. It can compute three sets of 4×4 Sorted QRD simultaneously. Various numbers
of sorting layers are supported for our proposed precoding criterion.
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