This paper describes a linear interference cancellation multi user detector for synchronous DS CDMA systems under the condition that all spread spectrum code waveforms have the constant cross correlating coefficien...This paper describes a linear interference cancellation multi user detector for synchronous DS CDMA systems under the condition that all spread spectrum code waveforms have the constant cross correlating coefficients. The basic idea is to get the estimation for total multiple access interference (MAI) of all users using a reference code waveform, then subtract the total MAI from the received signal. The structure of such a detector is nearly similar to the conventional detector. The BER expression obtained in the paper shows significant performance improvement compared to the other detectors.展开更多
This paper focuses on the linear transceiver design for multiple input multiple output（MIMO） interference channel（IC）, in which a bounded channel error model is assumed. Two optimization problems are formulated as...This paper focuses on the linear transceiver design for multiple input multiple output（MIMO） interference channel（IC）, in which a bounded channel error model is assumed. Two optimization problems are formulated as minimizing maximum per-user mean square error（MSE） and sum MSE with the per-transmitter power constraint. Since these optimization problems are not jointly convex on their variable matrices, the transmitter and receiver can be optimized alternately respectively. For each matrix, an approximated approach is presented where the upper bound of constraint is derived so that it has less semidefinite, thus the problem can be viewed as second-order-cone programming（SOCP） and gets less computational complexity. Compared with the conventional S-procedure method, the proposed approach achieves similar performance, but reduces the complexity significantly, especially for the system with large scale number of antennas.展开更多
An interference suppression algorithm is proposed to meet challenges of the traditional technique in dealing with the linear frequency modulation(LFM) interference,such as high loss of signal-to-noise ratio(SNR),the o...An interference suppression algorithm is proposed to meet challenges of the traditional technique in dealing with the linear frequency modulation(LFM) interference,such as high loss of signal-to-noise ratio(SNR),the output signal-to-interfer-ence-plus-noise ratio(SINR) sensitive to input interference-to-signal ratio(ISR) that results in an unstable synchronization,and the spectrum leakage serious in strong ISR situation.This approach firstly makes use of the windowed and lapped technique to the fractional Fourier transform(FRFT) to enhance the ISR improvement and lower the SNR loss.Then by weakening the interference and a secondary threshold process,interference energy can be suppressed as much as possible and the output SINR is less sensitive to the ISR.Finally,a joint fractional Fourier domain and time domain technique is proposed to overcome the residual interference energy caused by the strong interference or the discontinuous-phase interference.Theoretical analysis and simulation results show that the proposed algorithm can achieve better performance than the conventional methods in suppressing both the multi period LFM interference and the multi chirp-rate LFM interference,especially in the strong interference environment.展开更多
文摘This paper describes a linear interference cancellation multi user detector for synchronous DS CDMA systems under the condition that all spread spectrum code waveforms have the constant cross correlating coefficients. The basic idea is to get the estimation for total multiple access interference (MAI) of all users using a reference code waveform, then subtract the total MAI from the received signal. The structure of such a detector is nearly similar to the conventional detector. The BER expression obtained in the paper shows significant performance improvement compared to the other detectors.
基金supported by the National Natural Science Foundation of China (61401270, 61271283)
文摘This paper focuses on the linear transceiver design for multiple input multiple output（MIMO） interference channel（IC）, in which a bounded channel error model is assumed. Two optimization problems are formulated as minimizing maximum per-user mean square error（MSE） and sum MSE with the per-transmitter power constraint. Since these optimization problems are not jointly convex on their variable matrices, the transmitter and receiver can be optimized alternately respectively. For each matrix, an approximated approach is presented where the upper bound of constraint is derived so that it has less semidefinite, thus the problem can be viewed as second-order-cone programming（SOCP） and gets less computational complexity. Compared with the conventional S-procedure method, the proposed approach achieves similar performance, but reduces the complexity significantly, especially for the system with large scale number of antennas.
基金partially supported by the National Natural Science Foun-dation of China for Distinguished Young Scholars (Grant No. 60625104) the Foundation for Beijing Excellent Ph.D,Thesis (Grant No. 1320037010901)
文摘An interference suppression algorithm is proposed to meet challenges of the traditional technique in dealing with the linear frequency modulation(LFM) interference,such as high loss of signal-to-noise ratio(SNR),the output signal-to-interfer-ence-plus-noise ratio(SINR) sensitive to input interference-to-signal ratio(ISR) that results in an unstable synchronization,and the spectrum leakage serious in strong ISR situation.This approach firstly makes use of the windowed and lapped technique to the fractional Fourier transform(FRFT) to enhance the ISR improvement and lower the SNR loss.Then by weakening the interference and a secondary threshold process,interference energy can be suppressed as much as possible and the output SINR is less sensitive to the ISR.Finally,a joint fractional Fourier domain and time domain technique is proposed to overcome the residual interference energy caused by the strong interference or the discontinuous-phase interference.Theoretical analysis and simulation results show that the proposed algorithm can achieve better performance than the conventional methods in suppressing both the multi period LFM interference and the multi chirp-rate LFM interference,especially in the strong interference environment.
