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Massive Unsourced Random Access Under Carrier frequency offset

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ZTE Communications 2023年第3期21卷 45-53页

作者： XIE Xinyu WU Yongpeng YUAN Zhifeng MA Yihua Shanghai Jiao Tong University Shanghai 200240China ZTE Corporation Shenzhen 518057China State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen 518055China

Unsourced random access(URA)is a new perspective of massive access which aims at supporting numerous machine-type *** the appearance of carrier frequency offset(CFO),joint activity detection and channel estimation,which is vital for multiple-input and multiple-output URA,is a challenging *** handle the phase corruption of channel measurements under CFO,a novel compressed sensing algorithm is proposed,leveraging the parametric bilinear generalized approximate message passing framework with a Markov chain support model that captures the block sparsity structure of the considered angular domain *** uncoupled transmission scheme is proposed to reduce system complexity,where slot-emitted messages are reorganized relying on clustering unique user *** results reveal that the proposed transmission design for URA under CFO outperforms other potential methods.

关键词： activity detection channel estimation frequency offset massive machine-type communication massive MIMO

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Compensation of quadrature imbalance in an optical coherent OQPSK receiver in presence of frequency offset

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Frontiers of Optoelectronics 2011年第3期4卷 288-291页

作者： Xinying LI Bo HUANG Yufeng SHAO Junwen ZHANG Shumin ZOU Wuliang FANG Li TAO Jiangbo ZHU Chi NAN Department of Communication Science and Engineering State Key Laboratory of Application Specific Integrated Circuit (ASIC) and SystemFudan University

In this paper, we describe the impact of quadrature imbalance(QI) in the presence of frequency offset in an optical coherent offset quadrature phase shift keying(OQPSK) receiver. Arbitrary conjugate misalignment was realized in a 2×4 90° optical hybrid, and the ellipse correction(EC) method of quadrature imbalance was applied in our simulation. In the case of transmission,the EC method can significantly improve the system performance.

关键词： offset quadrature phase shift keying (OQPSK) quadrature imbalance (QI) ellipse fitting frequency offset

A Quadrature Coded OFDM for Reducing Effects of frequency offset in Wireless Transmission System

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The Journal of China Universities of Posts and Telecommunications 2001年第2期8卷 11-15页

作者： TONGXue-jian JIHong 等 SchoolofTelecommunicationEngineering BeijingUniversityofPostsandTelecommunicationsBeijing100876P.R.China SchoolofTelecommunicationEngineering BeijingUniversityofPostsandTelecommunicationsBeijing100

A new quadrature coded OFDM system is proposed. The transmitted data symbols are grouped in such format that the in phase side and the quadrature side of the symbols are arranged in opposite order. By analysis and simulation, the performance of the new system can be improved greatly, as well as the harmful influences on the system owing to frequency offset can be reduced effectively, which can combat the disadvantages of OFDM system.

关键词： orthogonal frequency division multiplexing( OFDM ) frequency offset interchannel interference( ICI ) equal gain combination( EGC )

Performance Analysis of OFDM with frequency offset and Correction Model

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The Journal of China Universities of Posts and Telecommunications 2003年第4期10卷 28-32页

作者： QIN Sheng-ping,YIN Chang-chuan,LUO Tao,YUE Guang-xin(School of Telecommunication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, P. R. China) School of Telecommunication Engineering Beijing University of Posts and Telecommunications 北京 100876

The performance of OFDM with frequency offset is analyzed and simulated inthis paper. It is concluded that the SIR is very large and the BER of OFDM system with frequencyoffset is strongly affected . A BER calculating method is introduced and simulated. Assumed that thefrequency offset is known , frequency offset correction model is discussed.

关键词： OFDM frequency offset ICI SIR

Compensation of Quadrature Imbalance in an Optical Coherent OQPSKReceiver in the presence of frequency offset and Phase Drift

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Compensation of Quadrature Imbalance in an Optical Coherent ...

Non-coherent sequence detection scheme for satellite-based automatic identification system

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作者：李欣颖 Yufeng Shao Bo Huang Junwen Zhang Shumin Zou Wuliang Fang Li Tao Jiangbo Zhu 迟楠 Department of Communication Science and Engineering State Key Lab of ASIC ＆ SystemFudan University

＜正＞In this letter,we describe the impact of quadrature imbalance（QI） in the presence of frequency offset and phase drift in an optical coherent offset-quadrature phase-shift-keying（OQPSK） *** the time domain,QI tilts and squeezes the square constellation into a diamond ***’ more,frequency offset continuously rotates the *** the presence of both QI and frequency offset,the constellation becomes *** conjugate misalignment was realized in a 2×4 90°optical hybrid, and the Gram-Schmidt orthogonalization procedure（GSOP） was applied in our simulation to compensate for quadrature imbalance in the ***,the GSOP enabled a set of nonorthogonal samples to be transformed into a set of orthogonal ***,a time domain method was adopted to compensate for chromatic dispersion（CD） due to fiber ***,the frequency offset between the received optical signal and LO signal,which was 200MHz in our simulation,was estimated and corrected by the phase increment estimation ***,we recovered the ideal square constellation after carrier phase estimation.

关键词： OQPSK Quadrature imbalance frequency offset Phase drift

来源： cnki会议评论

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Journal of Systems Engineering and Electronics 2017年第3期28卷 442-448页

作者： Haosu Zhou Jianxin Wang School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

The satellite-based automatic identification system (AIS) receiver has to encounter the frequency offset caused by the Doppler effect and the oscillator instability. This paper proposes a non-coherent sequence detection scheme for the satellite-based AIS signal transmitted over the white Gaussian noise channel. Based on the maximum likelihood estimation and a Viterbi decoder, the proposed scheme is capable of tolerating a frequency offset up to 5% of the symbol rate. The complexity of the proposed scheme is reduced by the state-complexity reduction, which is based on per-survivor processing. Simulation results prove that the proposed non-coherent sequence detection scheme has high robustness to frequency offset compared to the relative scheme when messages collision exists.

关键词： non-coherent sequence detection scheme satellite based automatic identification system frequency offset messages collision Viterbi decoder

Optimum weighting-coefficient-pair in inter-carrier interference self-cancellation scheme of OFDM system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1676-1684页

作者： Min-jian ZHAO Di ZHANG Bin CAI Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.

关键词： Orthogonal frequency division multiplexing (OFDM) frequency offset Inter-carrier interference (ICI) Polynomial cancellation coding (PCC) Optimum weighting-coefficient-pair (OWCP)

A Novel Surface Treatment Method for Improving the Antenna System Performance of Mobile Phones with Stainless Steel Frame

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Chinese Journal of Electronics 2014年第2期23卷 432-436页

作者： ZHONG Jiangwei LIU Dingxin LI Zhuo SUN Xiaowei Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Graduate University of Chinese Academy of Sciences Lenovo Research Shanghai Branch

A novel surface treatment method of plating Cu+PPS film/coating on a mobile phone’s stainless steel frame for improving the antenna system efficiencies is proposed. The mobile phone was measured in free space, in a silicon cover, and in the hand and cover simultaneously. It’s found that with this surface treatment, the total efficiency of the antenna system can be improved in all the four cases respectively by 14.22%,1.38%, 15.19% and 1.72% at 940 MHz(GSM900:880–960 MHz), 2.59%, 3.21%, 4.81% and 1.43% at 1720 MHz(DCS:1710–1880 MHz) and 6.34%, 2.85%, 9.83% and2.32% at 2100 MHz(WCDMA:1920–2170 MHz). This lowcost surface treatment method is an important breakthrough to improve antenna system performance of mobile phones especially for those with a stainless steel frame, and suitable for mass production.

关键词： Antenna efficiency Surface treatment Stainless steel Hand impacts frequency offset Insulation layer Wave-transparent material

The Effects of Time-Varying Channels on OFDM

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The Journal of China Universities of Posts and Telecommunications 2004年第1期11卷 1-5页

作者： QINSheng-ping QIUYan YINChang-chuan LIJian-feng YUEGuang-xin School of Telecommunication Engineering Beijing University of Posts and TelecommunicationsBeijing100876P.R.China Qingdao Institute of Architecture and Engineering Qingdao266033P.R.China

Time-varying impairments to OFDM signals can severely degrade the subcarrier orthogonality. In this paper, we analyze the ICI over time-varying channels, and present the method for analyzing the SIR. According to the results of simulation, we find frequency offset and Doppler spread can both degrade the performance of OFDM systems.

关键词： OFDM frequency offset Doppler spread ICI SIR