OFDM系统中基于二阶多项式奈奎斯特窗的边带加窗技术研究

针对在所有子载波上加载同一种窗函数的传统加窗方式，提出了一种新的边带加窗方式。边带加窗是根据窗函数的频谱特性，在不同频带子载波加载不同类型的窗函数以及选择相对应的滚降系数和参数的加窗方式。这种加窗方式相比传统加窗在缩短滚降叠加部分的时域长度后能够获得更好的信号传输效率，在不同频带使用不同类型、不同参数的窗函数来改善其带外衰减效果。仿真结果表明，边带加窗在缩短时域符号长度后与传统加窗相比，仍然能保持较好的带外衰减效果；并且通过比较在边带使用不同类型的窗函数以及与传统的加窗方式相比较后得出，在边带使用二阶多项式奈奎斯特窗函数(second order continuous window，SOCW）中使用升余弦窗函数的带外衰减效果要优于其他加窗方式。

Edge windowing of second order polynomial Nyquist windows in OFDM systems

Unlike the conventional windowing techniques where the same windowing is used for all the subcarriers within an OFDM(orthogonal frequency division multiplexing) symbol, this paper proposes a new edge windowing method. Edge windowing applies different window functions, roll-off factors and parameters in relevant frequency band according to the spectral characteristics of window functions. It can achieve better performance of the power spectrum of out-band attenuation and the transmission efficiency than the conventional windowing after using different window functions and reducing the roll-off overlay section. The simulation results indicate that after shorten the length of time domain symbol, edge windowing still keeps the performance of out-band attenuation as well as the performance of conventional windowing; in addition that the edge windowing which uses SOCW(second order continuous window) in edge subcarriers and raised cosine window in inner subcarriers has better performance of out-band attenuation than conventional windowing and other windowed modes.