N-continuous orthogonal frequency division multiplexing(NC-OFDM) is an outstanding method to suppress sidelobe for baseband OFDM signals in future 5G wireless communications.However,the precoder of NCOFDM usually caus...N-continuous orthogonal frequency division multiplexing(NC-OFDM) is an outstanding method to suppress sidelobe for baseband OFDM signals in future 5G wireless communications.However,the precoder of NCOFDM usually causes severe interference and high complexity.To alleviate these problems,this paper proposes an improved time-domain N-continuous OFDM(TD-NC-OFDM) by optimizing the smooth signal,which is the linear combination of rectangularly pulsed OFDM basis signals truncated by a smooth window.Furthermore,we show that the proposed scheme is with lower transceiver complexity and notable performance gain in signal-tointerference-plus-noise ratio(SINR).Lastly,simulation results show that the proposed low-interference TD-NC-OFDM can achieve similar sidelobe suppression performance,with negligible bit-error rate(BER) degradation,compared to conventional NC-OFDM.展开更多
N-continuous orthogonal frequency division multiplexing(NC-OFDM)is a promising multicarrier transmission waveform conceived for improving sidelobe suppression performance.To reduce the severe inband interference in tr...N-continuous orthogonal frequency division multiplexing(NC-OFDM)is a promising multicarrier transmission waveform conceived for improving sidelobe suppression performance.To reduce the severe inband interference in traditional NC-OFDM,we have proposed low-interference signal modeling for NC-OFDM.However,spectral leakage and error may be undesirably increased owing to the limited continuous differentiability of the smooth signal.In this paper,the low-interference scheme is investigated in terms of power spectrum density(PSD)and error performance,under the parameters of the highest derivative order(HDO)and the length of the smooth signal,to prove and quantify its advantages over traditional NC-OFDM.In the context of PSD,sidelobe decay is evaluated upon considering two discontinuous points due to the finite continuity of the smooth signal and its higher-order derivatives.Furthermore,it was shown that the low-interference scheme incurs small signal-to-noise ratio(SNR)loss and bit error rate(BER)for a short length of the smooth signal or a small HDO compared to traditional NC-OFDM.Meanwhile,due to the cyclostationarity loss imposed by the smooth signal,an effective solution is suggested for the time synchronization in a practical system.Based on analyses and simulation results,the trade offs between sidelobe suppression and BER are studied.展开更多
正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)是目前为止最有前景的调制技术,已经被大多数无线和有线通信标准采用。N-coutinuous正交频分复用是OFDM与认知无线电技术相结合转换而来的,但它的旁瓣抑制一直是一个需...正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)是目前为止最有前景的调制技术,已经被大多数无线和有线通信标准采用。N-coutinuous正交频分复用是OFDM与认知无线电技术相结合转换而来的,但它的旁瓣抑制一直是一个需要解决的问题。为在不影响旁瓣抑制性能的基础上降低算法和接收机的复杂性,文中提出了一种符号填充正交频分复用的时域算法,将n-连续OFDM校正符号只插入到保护间隔中,并将每个OFDM符号无缝连接起来,从而抑制了旁瓣。仿真结果表明,所提算法不影响旁瓣抑制性能,且易于实现,复杂度相比传统N-continuous正交频分复用系统有了明显降低。在K=72的不同信道,信号的误码率降低5 dB。文中还用matlab的simulink来模拟现场可编程门阵列(Field-Programmable Gate Array,FPGA)的N-coutinuous正交频分复用系统的仿真。FPGA具有很大的灵活性,在数字信号处理上具有更快的计算速度和较小的面积,其成本低,风险小,时间上亦具有优势。展开更多
Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) and N-continuous OFDM are both improved multi-carrier modulation (MCM) techniques for the transmission of signals over multipath fading channels. In this ...Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) and N-continuous OFDM are both improved multi-carrier modulation (MCM) techniques for the transmission of signals over multipath fading channels. In this paper, we aim to compare these two techniques with respect to out-of-band radiation, bit error ratio (BER) and calculation complexity. Analysis and simulation results show that, compared to the N-continuous OFDM, the OFDM/OQAM has lower out-of-band radiation, calculation consumption and similar BER performance.展开更多
基金financial support of the National S&T Major Project(No.2014ZX03004003)the National Science Foundation of China under Grant number 61671134+1 种基金the open research fund of National Mobile Communications Research Laboratory,Southeast University (No.2015D09)the Fundamental Research Funds for the Central Universities(No. ZYGX2015J011) is gratefully acknowledged
文摘N-continuous orthogonal frequency division multiplexing(NC-OFDM) is an outstanding method to suppress sidelobe for baseband OFDM signals in future 5G wireless communications.However,the precoder of NCOFDM usually causes severe interference and high complexity.To alleviate these problems,this paper proposes an improved time-domain N-continuous OFDM(TD-NC-OFDM) by optimizing the smooth signal,which is the linear combination of rectangularly pulsed OFDM basis signals truncated by a smooth window.Furthermore,we show that the proposed scheme is with lower transceiver complexity and notable performance gain in signal-tointerference-plus-noise ratio(SINR).Lastly,simulation results show that the proposed low-interference TD-NC-OFDM can achieve similar sidelobe suppression performance,with negligible bit-error rate(BER) degradation,compared to conventional NC-OFDM.
基金supported in part by the National Natural Science Foundation of China under Grant 61901298in part by the Natural Science Foundation of Tianjin under Grant 20JCQNJC00300in part by the Science&Technology Development Fund of Tianjin Education Commission for Higher Education under Grant 2018KJ211.
文摘N-continuous orthogonal frequency division multiplexing(NC-OFDM)is a promising multicarrier transmission waveform conceived for improving sidelobe suppression performance.To reduce the severe inband interference in traditional NC-OFDM,we have proposed low-interference signal modeling for NC-OFDM.However,spectral leakage and error may be undesirably increased owing to the limited continuous differentiability of the smooth signal.In this paper,the low-interference scheme is investigated in terms of power spectrum density(PSD)and error performance,under the parameters of the highest derivative order(HDO)and the length of the smooth signal,to prove and quantify its advantages over traditional NC-OFDM.In the context of PSD,sidelobe decay is evaluated upon considering two discontinuous points due to the finite continuity of the smooth signal and its higher-order derivatives.Furthermore,it was shown that the low-interference scheme incurs small signal-to-noise ratio(SNR)loss and bit error rate(BER)for a short length of the smooth signal or a small HDO compared to traditional NC-OFDM.Meanwhile,due to the cyclostationarity loss imposed by the smooth signal,an effective solution is suggested for the time synchronization in a practical system.Based on analyses and simulation results,the trade offs between sidelobe suppression and BER are studied.
文摘Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) and N-continuous OFDM are both improved multi-carrier modulation (MCM) techniques for the transmission of signals over multipath fading channels. In this paper, we aim to compare these two techniques with respect to out-of-band radiation, bit error ratio (BER) and calculation complexity. Analysis and simulation results show that, compared to the N-continuous OFDM, the OFDM/OQAM has lower out-of-band radiation, calculation consumption and similar BER performance.
