A Novel Low-Complexity Precoded OFDM System With Reduced PAPR
A Novel Low-Complexity Precoded OFDM System With Reduced PAPR
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DOI：
10.1109/tsp.2015.2389751
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发表时间：
2015-03-15
影响因子：
5.4
通讯作者：
Su, Hsuan-Jung
中科院分区：
文献类型：
--
作者：
Wang, Sen-Hung;Li, Chih-Peng;Su, Hsuan-Jung
基于Walsh-Hadamard矩阵的T-OFDM预编码系统可以降低传统预编码正交频分复用(OFDM)系统的计算复杂度和峰均功率比(PAPR)。本文提出了一种新的预编码方案，以进一步降低T-ofdm的计算复杂度和峰均比。在该方案中，预编码矩阵与离散傅立叶逆变换相结合，在发送端构造新的变换矩阵。值得注意的是，变换矩阵既是酉阵又是循环的，每一列都是一个完美的高斯整数序列，其中只包含四个非零元素{+/-1，+/-i}。对于所提出的预编码方案，还构造了一个低复杂度的接收器。推导了频率选择性衰落信道下T-OFDM和预编码方案的误码率的闭合表达式。误码率的仿真结果与数学推导结果吻合较好。此外，还证明了当预编码矩阵设计成完全频率分集时，T-OFDM和所提出的方案具有相同的误码率性能。然而，与T-ofdm相比，该方案具有更好的PAPR性能和更低的计算复杂度。
The computational complexity and peak-to-average power ratio (PAPR) of conventional precoded orthogonal frequency division multiplexing (OFDM) systems can be reduced using a T-OFDM precoded system based on the Walsh-Hadamard matrix. The present paper proposes a novel precoding scheme for further reducing the computational complexity and PAPR of T-OFDM. In the proposed scheme, the precoding matrix is combined with an inverse discrete Fourier transform to construct a new transform matrix at the transmitter. Notably, the transform matrix is both unitary and circulant, with each column being a perfect Gaussian integer sequence containing just four non-zero elements of {+/-1,+/-i}. A low-complexity receiver is additionally constructed for the proposed precoding scheme. A closed-form expression is derived for the bit error rate (BER) in T-OFDM and the proposed precoding scheme under frequency-selective fading channels. The simulation results for the BER are shown to be in good agreement with the mathematical derivations. In addition, it is demonstrated that T-OFDM and the proposed scheme have an equivalent BER performance when their precoding matrices are designed in such a way as to obtain full frequency diversity. However, the proposed scheme has a better PAPR performance and a lower computational complexity than T-OFDM.