The theoretical lower bounds on mean squared channel estimation errors for typical fading channels are presented by the infinite-length and non-causal Wiener filter and the exact closed-form expressions of the lower b...The theoretical lower bounds on mean squared channel estimation errors for typical fading channels are presented by the infinite-length and non-causal Wiener filter and the exact closed-form expressions of the lower bounds for different channel Doppler spectra are derived. Based on the obtained lower bounds on mean squared channel estimation errors, the limits on bit error rate （BER） for maximal ratio combining （MRC） with Gaussian distributed weighting errors on independent and identically distributed （i. i. d） fading channels are presented. Numerical results show that the BER performances of ideal MRC are the lower bounds on the BER performances of non-ideal MRC and deteriorate as the maximum Doppler frequency increases or the SNR of channel estimate decreases.展开更多
An asynchronous transmission scenario for non-orthogonal multiple access(NOMA)user signals with arbitrary phase offset is investigated in this paper.To improve the system performance in the user power-balanced conditi...An asynchronous transmission scenario for non-orthogonal multiple access(NOMA)user signals with arbitrary phase offset is investigated in this paper.To improve the system performance in the user power-balanced conditions,we adopt a synthetic detection method at the receiver,i.e.,the jointly optimal maximal likelihood detection aided triangular successive interference cancellation(JO ML-TSIC)method.Analytical bit error rate(BER)solutions are obtained for a two-user case with the optimal,intentional onehalf symbol period time delay implemented between the user signals.Furthermore,closed-form BER solutions for the case using the triangular successive interference cancellation(TSIC)detection method are also derived for comparisons.Numerical results show that the JO ML-TSIC receiver for the asynchronous system outperforms the TSIC receiver as well as the synchronous successive interference cancellation(SIC)receiver in all the conditions concerned.The results also show that the superiority of the JO ML-TSIC receiver is strengthened when the signals experience flat Rayleigh fading channels compared to the TSIC and the synchronous SIC receivers.展开更多
Traditional intensity modulated two-level electrical time-division multiplexing （ETDM） transmission systems working at 100 -112 Gbit/s were investigated. The complete ETDM systems based on monolithically integrated ...Traditional intensity modulated two-level electrical time-division multiplexing （ETDM） transmission systems working at 100 -112 Gbit/s were investigated. The complete ETDM systems based on monolithically integrated transmitter and receiver modules were demonstrated with biterror-rate （BER） performance of 10-s at 107 Gbit/s, and near error-free standard forward error correction （FEC） threshold （2 × 10 -3） at 112 Gbit/s. The experiment results showed that directly modulated high-speed ETDM transmission systems with the symbol rates at 100 Gbaud and beyond were promising candidate for cost-effective 100 GbE applications and might be a preform of the next generation of Terabit/s Ethernet.展开更多
针对衰落信道,提出了一种新的MC-CDMA下行链路多用户检测方案。该方案基于最小误比特率(Minimum bit error rate,MBER)准则,并利用梯度下降法实现。通过采用内核密度估计的方法来估计误码率函数,可将该方案推广到自适应的最小误比特率(L...针对衰落信道,提出了一种新的MC-CDMA下行链路多用户检测方案。该方案基于最小误比特率(Minimum bit error rate,MBER)准则,并利用梯度下降法实现。通过采用内核密度估计的方法来估计误码率函数,可将该方案推广到自适应的最小误比特率(Least bit error rate,LBER)多用户检测算法。仿真结果表明,与传统归一化自适应最小均方误差(Normalized least mean square,NLMS)算法相比,LBER具有更好的收敛性能和误码性能。展开更多
文摘The theoretical lower bounds on mean squared channel estimation errors for typical fading channels are presented by the infinite-length and non-causal Wiener filter and the exact closed-form expressions of the lower bounds for different channel Doppler spectra are derived. Based on the obtained lower bounds on mean squared channel estimation errors, the limits on bit error rate （BER） for maximal ratio combining （MRC） with Gaussian distributed weighting errors on independent and identically distributed （i. i. d） fading channels are presented. Numerical results show that the BER performances of ideal MRC are the lower bounds on the BER performances of non-ideal MRC and deteriorate as the maximum Doppler frequency increases or the SNR of channel estimate decreases.
基金supported by the National Natural Science Foundation of China (Grant No. 62022019)
文摘An asynchronous transmission scenario for non-orthogonal multiple access(NOMA)user signals with arbitrary phase offset is investigated in this paper.To improve the system performance in the user power-balanced conditions,we adopt a synthetic detection method at the receiver,i.e.,the jointly optimal maximal likelihood detection aided triangular successive interference cancellation(JO ML-TSIC)method.Analytical bit error rate(BER)solutions are obtained for a two-user case with the optimal,intentional onehalf symbol period time delay implemented between the user signals.Furthermore,closed-form BER solutions for the case using the triangular successive interference cancellation(TSIC)detection method are also derived for comparisons.Numerical results show that the JO ML-TSIC receiver for the asynchronous system outperforms the TSIC receiver as well as the synchronous successive interference cancellation(SIC)receiver in all the conditions concerned.The results also show that the superiority of the JO ML-TSIC receiver is strengthened when the signals experience flat Rayleigh fading channels compared to the TSIC and the synchronous SIC receivers.
基金Supported by the European Committee6th Research Framework Program in the Project HECTO
文摘Traditional intensity modulated two-level electrical time-division multiplexing （ETDM） transmission systems working at 100 -112 Gbit/s were investigated. The complete ETDM systems based on monolithically integrated transmitter and receiver modules were demonstrated with biterror-rate （BER） performance of 10-s at 107 Gbit/s, and near error-free standard forward error correction （FEC） threshold （2 × 10 -3） at 112 Gbit/s. The experiment results showed that directly modulated high-speed ETDM transmission systems with the symbol rates at 100 Gbaud and beyond were promising candidate for cost-effective 100 GbE applications and might be a preform of the next generation of Terabit/s Ethernet.
文摘针对衰落信道,提出了一种新的MC-CDMA下行链路多用户检测方案。该方案基于最小误比特率(Minimum bit error rate,MBER)准则,并利用梯度下降法实现。通过采用内核密度估计的方法来估计误码率函数,可将该方案推广到自适应的最小误比特率(Least bit error rate,LBER)多用户检测算法。仿真结果表明,与传统归一化自适应最小均方误差(Normalized least mean square,NLMS)算法相比,LBER具有更好的收敛性能和误码性能。
