| Summary: | 碩士 === 國立中正大學 === 通訊工程研究所 === 104 === As the wireless communications prevails, multiple-input multiple-output with orthogonal
frequency division multiplexing (MIMO-OFDM) techniques have attracted
much attention in recent years. Among the various MIMO techniques, the limited feedback
precoding is the focus of this thesis. The LTE downlink codebook is considered in
this thesis. The precoding matrix at the transmitter side is selected from a finite-sized
codebook. Using selection criterion we can pick out the most suitable precoding matrix
from the codebook to against channel fading. We use MMSE Trace Criterion in this
thesis, because it computational complexity is lower. We use LDLH matrix decomposition,
and backward substitution to avoid matrix inversion operations. We improve
previous thesis Complex Matrix Multiplication-1 utilizing LTE downlink codebook features
to reduce the computational complexity, and improve speed of LDLH decomposition
architectures and backward substitution architectures When the frequency is
170MHz,we can pick out codeword within 0.8ms. In 3GPP LTE standard periodic
channel-state reports are often as once every 2ms. In this thesis, the designed hardware
architecture was synthesized and verified in the Xilinx ISE 12.2 environment and also
synthesized by Design Compiler. The designed architecture requires is 156.88K gates
and work with frequency 170 MHz under the TSMC 90 nm CMOS technology. The
designed architecture computes such precoding matrices with throughput rate 24.28M
matrices/second.
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