统一扩频测控系统是在MC-CDMA为主的多载波通信体制的基础上建立起来的,MC-CDMA等多载波通信体制的基础是正交频分复用(orthogonal frequency division multiplexing,OFDM)技术;相对于传统的单载波系统,采用OFDM技术的统一扩频测控系统...统一扩频测控系统是在MC-CDMA为主的多载波通信体制的基础上建立起来的,MC-CDMA等多载波通信体制的基础是正交频分复用(orthogonal frequency division multiplexing,OFDM)技术;相对于传统的单载波系统,采用OFDM技术的统一扩频测控系统对于载波频率偏移和相位噪声的影响尤为敏感,所以在系统设计时必须考虑相噪的跟踪与抑制;文章在分析相位噪声对统一扩频测控系统性能影响的基础上,用有限个正弦波近似的方法建立相噪的频域线性参数模型,并基于该模型提出了加入相噪估计导频来跟踪相噪的方法;由于导频与数据子载波之间有空子载波作为保护间隔,该方法可以估计出相噪的高阶频谱分量,从而达到了很好的相噪抑制效果。展开更多
通过对正交频分复用(orthogonal frequency division multiplexing—OFDM)峰均比的研究,提出一种改进压扩C变换的方法来降低OFDM系统中的峰均比(PAPR).该算法是在原有的压扩C变换方法基础上,通过适当修改某些参数,来达到进一步降低PAPR...通过对正交频分复用(orthogonal frequency division multiplexing—OFDM)峰均比的研究,提出一种改进压扩C变换的方法来降低OFDM系统中的峰均比(PAPR).该算法是在原有的压扩C变换方法基础上,通过适当修改某些参数,来达到进一步降低PAPR的目的.仿真结果表明该改进算法更有效地抑制了PAPR的同时,系统的误码率略有增加,而算法复杂度与传统算法相比并没有提升.该改进算法是误码率与峰均比性能的折中,具有实用性.展开更多
The primary goal of this project was educational: to demonstrate Software Defined Radio based prototyping using Visual C++ Express and Code Composer Studio. More specifically an IEEE802.11a Phy [1] compliant baseband ...The primary goal of this project was educational: to demonstrate Software Defined Radio based prototyping using Visual C++ Express and Code Composer Studio. More specifically an IEEE802.11a Phy [1] compliant baseband processor was written in C++ and a radio link demonstrated “live” using a standard PCand the DSK6713 kit from Spectrum Digital [2] for baseband processing at the receiver and transmitter side respectively. To reduce costs without loss of educational value (the algorithms remains the same), the bandwidth was scaled down from 20MHz to 6 kHz to be able to utilize cheap narrowband COTS RF frontends operating at an intermediate frequency of only 12 kHz at the transmitter and receiver sides. This was easily achieved by just reducing the OFDM symbol rate by a suitable factor. The development process is described in detail, emphasizing development tricks to facilitate debugging of this kind of complex baseband processing. For educational purposes some other simpler waveforms was implemented as well.展开更多
文摘统一扩频测控系统是在MC-CDMA为主的多载波通信体制的基础上建立起来的,MC-CDMA等多载波通信体制的基础是正交频分复用(orthogonal frequency division multiplexing,OFDM)技术;相对于传统的单载波系统,采用OFDM技术的统一扩频测控系统对于载波频率偏移和相位噪声的影响尤为敏感,所以在系统设计时必须考虑相噪的跟踪与抑制;文章在分析相位噪声对统一扩频测控系统性能影响的基础上,用有限个正弦波近似的方法建立相噪的频域线性参数模型,并基于该模型提出了加入相噪估计导频来跟踪相噪的方法;由于导频与数据子载波之间有空子载波作为保护间隔,该方法可以估计出相噪的高阶频谱分量,从而达到了很好的相噪抑制效果。
文摘通过对正交频分复用(orthogonal frequency division multiplexing—OFDM)峰均比的研究,提出一种改进压扩C变换的方法来降低OFDM系统中的峰均比(PAPR).该算法是在原有的压扩C变换方法基础上,通过适当修改某些参数,来达到进一步降低PAPR的目的.仿真结果表明该改进算法更有效地抑制了PAPR的同时,系统的误码率略有增加,而算法复杂度与传统算法相比并没有提升.该改进算法是误码率与峰均比性能的折中,具有实用性.
文摘The primary goal of this project was educational: to demonstrate Software Defined Radio based prototyping using Visual C++ Express and Code Composer Studio. More specifically an IEEE802.11a Phy [1] compliant baseband processor was written in C++ and a radio link demonstrated “live” using a standard PCand the DSK6713 kit from Spectrum Digital [2] for baseband processing at the receiver and transmitter side respectively. To reduce costs without loss of educational value (the algorithms remains the same), the bandwidth was scaled down from 20MHz to 6 kHz to be able to utilize cheap narrowband COTS RF frontends operating at an intermediate frequency of only 12 kHz at the transmitter and receiver sides. This was easily achieved by just reducing the OFDM symbol rate by a suitable factor. The development process is described in detail, emphasizing development tricks to facilitate debugging of this kind of complex baseband processing. For educational purposes some other simpler waveforms was implemented as well.
