现有调制方法主要基于正弦函数,并利用其正交性传输信息.本文突破对调制信号的正弦函数约束和正交性限定,从椭圆球面波函数(Prolate Spheroidal Wave Function,PSWF)的高能量聚集性和框架函数系的过完备特性入手,提出基于PSWF框架的非正交脉冲波形调制方法(Nonorthogonal Pulse Shape Modulation,NPSM).该方法利用频谱交叠的非正交PSWF获得了优良的功率谱特性,同时利用框架函数的过完备特性,在提高系统频带利用率的同时,有效消除码间串扰.与目前广泛应用的QAM-OFDM方法进行性能相比,在相同调制幅度数和误码率的情况下有2d B的优势,且该优势随调制进制数增加而扩大,同时其调制信号具有良好的功率谱特性,PAPR性能比相同频带利用率的QAM-OFDM有3d B的优势.
The existing modulations mainly transmit information by the orthogonality of sinusoidal function. The sinusoidal function restriction and the orthogonality requirement for the modulation signals are eliminated,and a novel nonorthogonal pulse shape modulation( NPSM) based on the prolate spheroidal w ave function( PSWF) and over-complete frames is proposed. The NPSM employs the nonorthogonal PSWF pulses w ith high energy concentration to achieve excellent pow er spectral density( PSD) performance. The over-complete property of frames is utilized to improve the spectral efficiency w ithout the intersymbol interference. Compared w ith the popular QAM-OFDM,the NPSM based on PSWF frames has an advantage of 2d B w ith the same modulation amplitude number and BER,and the advantage is more obvious as the modulation amplitude number increases. The PAPR of the modulated signals for NPSM based on PSWF frames is 3d B low er than QAM-OFDM w ith the same spectral efficiency.