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constant envelope FrFT OFDM: spectral and energy efficiency analysis

Journal of Systems Engineering and Electronics 2019年第3期30卷 467-473页

作者： DIDA Mussa Ally HUAN Hao TAO Ran WANG Teng URYNBASSAROVA Didar School of Information and Electronics Beijing Institute of Technology School of Computational and Communication Science and Engineering Nelson Mandela African Institute of Science and Technology

constant envelope with a fractional Fourier transformorthogonal frequency division multiplexing(CE-FrFT-OFDM) is a special case of a constant envelope OFDM(CE-OFDM), both being energy efficient wireless communication techniques with a 0 dB peak to average power ratio(PAPR). However, with the proper selection of fractional order, the first technique has a high bit error rate(BER) performance in the frequency-time selective *** paper performs further analysis of CE-FrFT-OFDM by examining its spectral efficiency(SE) and energy efficiency(EE) and compare to the famous OFDM and Fr FT-OFDM techniques. Analytical and comprehensive simulations conducted show that, the CE-Fr FT-OFDM has five times the EE of OFDM and Fr FT-OFDM systems with a slightly less SE. Increasing CE-FrFT-OFDM’s transmission power by increasing its amplitude to 1.7 increases its SE to match that of the OFDM and Fr FT-OFDM systems while slightly reducing its EE by 20% to be four times that of OFDM and Fr FTOFDM systems. OFDM and Fr FT-OFDM’s amplitude fluctuations cause rapid changing output back-off(OBO) power requirements and further reduce power amplifier(PA) efficiency while CE-FrFTOFDM stable operational linear range makes it a better candidate and outperforms the other techniques when their OBO exceeds1.7. Higher EE and low BER in time-frequency selective channel are attracting features for CE-FrFT-OFDM deployment in mobile devices.

关键词： fractional Fourier transform(FrFT) constant envelope spectral efficiency(SE) energy efficiency(EE) high power amplifier

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DualQPSK Modulation:Achieving Theoretical Lower Bounds for constant-envelope Transmission on Compass B3 Band

DualQPSK Modulation:Achieving Theoretical Lower Bounds for C...

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第三届中国卫星导航学术年会

作者： Kai Zhang Feixue Wang Gang Ou Guangfu Sun Satellite Navigation R&D Center National Univ. of Defense Technology Changsha 410073 China

Future GNSS systems introduce the requirement to multiplex several binary spreading codes into a constant envelope on the same carrier. This paper studies the 4-code multiplexing model and presents a novel DualQPSK modulation that multiplexes four codes as two QPSK signals at the same center frequency. The analytical expression of DualQPSK is derived from the constellation of Alternative-BOC modulation. Then the proposed DualQPSK modulation is compared with the theoretical lower bound and conventional multiplexing techniques as Interplex and Majority Vote. The result shows that DualQPSK has the optimum efficiency and is actually an implementation that achieves the theoretical lower bound. The baseline of COMPASS B3 band contains a BOC（15,2.5） signal and a QPSK（10） signal. The special constraint is that the backward compatible QPSK（10） signal must be maintained, which makes the traditional techniques inapplicable. The BOC（15,2.5） and QPSK（10） signals modulated by DualQPSK are investigated in aspects of combining efficiency, power spectrum and inter-modulation interference. It is proven that optimum transmission efficiency and complete receiver compatibility is obtained by DualQPSK. The DualQPSK modulation is demonstrated as an attractive solution for COMPASS B3 signals.

关键词： GNSS COMPASS Dual QPSK constant envelope

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Study on Design of Interplex Method for GNSS Signal

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China Communications 2014年第A02期11卷 23-29页

作者： FENG Youjun WANG Zhong CHEN Dandan Department of Information Technology Sichuan Tourism University Chengdu 610100 Sichuan Province China School of Electrical and Information Engineering Sichuan University Chengdu 610065 Sichuan Province China

In order to satisfy sending multi-channel navigation signals in one frequency for modern GNSS（Global Navigation Satellite System）, the principle of Interplex multiplexing were introduced. And the three-way multiplexing structure and the four-way multiplexing method were also optimized. The Galileo E1 signal, as the example of Interplex reuse, was analyzed in detail. The power configuration of the multiplexing efficiency and the minimum of the multiplexing efficiency were obtained.

关键词： satellite navigation constant envelope Interplex multiplexing efficiency

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Assessing CBOC Signal Quality using Scatterplot

Assessing CBOC Signal Quality using Scatterplot

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第三届中国卫星导航学术年会

作者： GUO Yuanyuan, WANG Gang China Academy of Space Technology(Xi’an) NO.150 Weiqu West Street, Chang’an District, Xi’an, Shaanxi, 710100, China

The Interplex modulation is particularly suitable for satellite navigation system. But the constant envelope of the signal will be destroyed by the limited bandwidth of navigation system, then distorted by the non-linearity of HPA and filtering of post HPA filter, in the end introducing range error. This paper introduces the simulation model of the navigation satellite transmission channel. By simulation in MATLAB, we assess the impact of transmission channel on CBOC Interplex and CBOC signal adopting the evaluation methods and parameters of scatterplot. The so-called CBOC scatterplot is obtained with the data channel as I component and the pilot channel as Q component, and then compared with the CBOC Interplex scatterplot. We can describe the quality and distribution of CBOC signal directly using this technique.

关键词： constant envelope scatterplot CBOC signal

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Research on the Influence of Satellite Signal Transmission Channel’s Non-Ideal Characteristics on the Quality of Different envelope Signals

Research on the Influence of Satellite Signal Transmission C...

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第十三届中国卫星导航年会

作者： Qianqian Yang Chengyan He Zhigang Hu Zibin Han National Time Service Center Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Precise Positioning and Timing Technology Chinese Academy of Sciences Wuhan University

At present, most satellite navigation systems use constant envelope multiplexed signals, in order to reduce the non-linear influence of the power amplifier as much as possible. However, the actual signal transmission channel cannot be purely ideal. Various amplitude-frequency or phase-frequency distortions that may occur will affect the signal envelope characteristics and ranging performance, resulting in a certain difference between the actual signal received by the user and its theoretical design. Research has shown that the performance of the constant envelope signal after passing through the non-ideal channel may not be better than the corresponding non-constant envelope signal. In order to fully understand the specific effects of various non-ideal characteristics of the channel on the non-constant envelope signal and to judge under which non-ideal characteristics the non-constant envelope signal can show better performance, so as to provide new ideas for the design of navigation signals. This article first studies the non-ideal characteristics of the satellite signal transmission channel and establishes five channel distortion models. The BDS-3 B1 constant envelope and nonconstant envelope simulation ideal signals are used as the research signals of this article, use the software receiver to evaluate the signal quality of the ideal signal after the distortion model, and use the evaluation index S-curve zero-crossing deviation to express the signal’s ranging performance. Finally, the quantitative analysis and comparison of the ranging performance of different envelope signalsunder the influence of various distortions are realized. The results show that: Inaddition to amplitude ripple distortion, non-constant envelope signals show better ranging performance overall under the same distortion conditions. The research results of this paper have certain reference value for signal design and signal quality evaluation.

关键词： Navigation signal Transmission channel Non-ideal characteristics constant envelope Non-constant envelope Signal quality

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