中文摘要：

直角的频率部门 multiplexing (OFDM ) 被认为是答应之一为认知收音机(CR ) 策划系统，由于它在塑造的光谱的灵活性。然而，光谱槽口的传统的方法没能压制足够的 out-of-band 漏，导致与准许的用户(LU ) 一起的干扰。塑造计划的一个新奇系列在这篇文章被建议，在有干扰抑制顺序(ISS ) 的 precoder 第一次为在基于 OFDM 的 CR 系统塑造 OFDM 信号的光谱被介绍的地方。和 ISS 矩阵的 precoder 矩阵被最小化 out-of-band 干扰的力量获得，它导致 OFDM 信号的足够的干扰抑制到 LU。分析和模拟结果证明建议计划罐头显著地以 precoding 效率的一点成本压制干扰力量到 LU。同时， peak-to-average-power-ratio (PAPR ) 是不变的，在使隧道褪色的瑞利上的 bit-error-rate (BER ) 表演被改进。

英文摘要：

Orthogonal frequency division multiplexing （OFDM） is considered to be one of the promising schemes for cognitive radios （CR） systems, due to its flexibility in spectrum shaping. However, the traditional way of spectrum-notching failed to suppress out-of-band leakage enough, resulting in interference with licensed users （LUs）. A novel spectrum shaping scheme is proposed in this article, where a precoder with interference suppression sequence （ISS） is for the first time introduced for shaping the spectrum of OFDM signals in OFDM-based CR systems. The precoder matrix together with ISS matrix is obtained by minimizing the power of out-of-band interference, which results in the sufficient interference suppression of OFDM signal to LUs Analysis and simulation results show that the proposed scheme can significantly suppress the interference power to LUs at a little cost of precoding efficiency. Meanwhile, the peak-to-average-power-ratio （PAPR） is invariable and the bit-error-rate （BER） performance over Rayleigh fading channel is improved.