北京邮电大学学报

  • EI核心期刊

北京邮电大学学报 ›› 2005, Vol. 28 ›› Issue (6): 8-10.doi: 10.13190/jbupt.200506.8.fand

• 论文 • 上一篇    下一篇

基于伪随机序列处理技术的ZPOFDM系统

范达,曹志刚,樊平毅   

  1. 清华大学 电子工程系, 北京 100084
  • 出版日期:2005-12-28 发布日期:2005-12-28

A Performance Improvement of Zero Padding OFDM System with Pseudorandom Sequence Processing Technique

FAN Da,CAO Zhigang,FAN Pingyi   

  1. Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
  • Online:2005-12-28 Published:2005-12-28

摘要:

针对补零正交频分复用(ZPOFDM)系统中基于快速傅里叶变换(FFT)的接收机性能较差的情形,提出了一种伪随机序列处理技术. 该技术将一段伪随机序列的元素分别乘在快速傅里叶逆变换(IFFT)矩阵的各行,则可以改善IFFT矩阵各列之间的相关特性,从而提高OFDM系统的性能. 并且由于伪随机序列的元素为±1,所以改进后的IFFT矩阵仍然保持归一性和正交性. 利用该技术可以对ZPOFDM、ZPOFDMOLA(overlap add, 重叠相加)以及ZPOFDMFAST等方法进行改进. 仿真部分对改进方法和原方法进行了性能对比,采用Hiperlan2的A、E 2种信道模型,在误比特率为10-4 时,改进方法在性能上至少提高了22?dB. 仿真结果验证了伪随机序列处理技术的有效性.

关键词: 正交频分复用, 伪随机序列, 相关特性, 信道状态信息, 误比特率

Abstract:

ZPOFDM(zero padding orthogonal frequency division multiplexing)has the disadvantage that the simple FFT (fast fourier transform) based receiver does not perform well. Therefore, a pseudorandom sequence processing technique that is each row of the IFFT (inverse fast fourier transform) matrix multiplies with a bit of a pseudorandom sequence is proposed. The technique changes the correlation properties of the IFFT matrix columns, and hence improves the performance over multipath channels. The modified IFFT matrix is still unitary and orthogonal, since the multiplication by ±1 of the IFFT unitary matrix rows doesn't destroy its unitarity and orthogonality. This technique is analized theoretically and applied to ZPOFDM, ZPOFDMOLA and ZPOFDMFAST. Simulation results verify the improved performance of the modified methods using this technique. The Hiperlan2 Channel models A and E are considered in our simulation. For the two channel models, the modified methods exhibit at least 22?dB advantage in SNR at 10-4 BER (bit error rate).

Key words: orthogonal frequency division multiplexing, pseudorandom sequence, correlation properties, channel state information, bit error rate

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