In order to improve the bit error rate(BER) performance of turbo codes with short frame size at a wide range of signal to noise ratio(SNR),a new method by optimizing the bit energy is proposed.At first,a formula deriv...In order to improve the bit error rate(BER) performance of turbo codes with short frame size at a wide range of signal to noise ratio(SNR),a new method by optimizing the bit energy is proposed.At first,a formula derived from the Union Bound is introduced.It describes the relations between the bit error rate distribution and the minimum weight distribution.And then,by mathematically optimizing the formula,the energy for every bit of the codeword is optimized to achieve the minimum BER at high SNR region.At last,an adjustable parameter is employed to compensate the degradations of BER at low and moderate SNR regions.Case studies indicate that the improvements of BER for turbo codes with short frame size are significant at a wide range of SNR.展开更多
There are considerable literatures on the Bit Error Rate(BER)evaluation of DifferentialDetection of Gaussian Minimum Shift Keying(DDGMSK)system using Decision Feedback(DF),butmost of them give the performance based on...There are considerable literatures on the Bit Error Rate(BER)evaluation of DifferentialDetection of Gaussian Minimum Shift Keying(DDGMSK)system using Decision Feedback(DF),butmost of them give the performance based on the Monte Carlo Error Counting(MCEC)technique.Fromthe probability distribution of the phase angle between two vectors perturbed by Gaussian noises,theformulae of BER are derived for the performance analysis of DDGMSK system with DF in this letter.Considering the m-bit dock-tailed sequence,the new formulae of Gaussian Minimum Shift Keying(GMSK)modulated phase and the Time-Varying Signal to Noise Ratio(TVSNR)of the demodulatedsignal are presented,and it is proved that the relationship between the TVSNR of the demodulatedsignal and the size of eye opening is not inevitable.Simulation results show that the theoretical in-vestigation gives analogous results with the MCEC technique.The formulae presented are useful for theperformance analysis of systems using GMSK as modulating and demodulating method,for instance,the analysis of synchronous performance of frequency-hopping communication system.展开更多
In recent times, there has been growing interests in integration of voice, data and video traffic in wireless communication networks. With these growing interests, WCDMA has immerged as an attractive access technique....In recent times, there has been growing interests in integration of voice, data and video traffic in wireless communication networks. With these growing interests, WCDMA has immerged as an attractive access technique. The performance of WCDMA system is deteriorated in presence of multipath fading environment. The paper presents space-time coded minimum mean square error (MMSE) Decision Feedback Equalizer (DFE) for wideband code division multiple access (WCDMA) in a frequency selective channel. The filter coefficients in MMSE DFE are optimized to suppress noise, intersymbol interference (ISI), and multiple access interference (MAI) with reasonable system complexity. For the above structure, we have presented the estimation of BER for a MMSE DFE using computer simulation experiments. The simulation includes the effects of additive white Gaussian noise, multipath fading and multiple access interference (MAI). Furthermore, the performance is compared with standard linear equalizer (LE) and RAKE receiver. Numerical and simulation results show that the MMSE DFE exhibits significant performance improvement over the standard linear equalizer (LE) and RAKE receiver.展开更多
A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels wit...A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels with multiple single-antenna users. And an analytical error model is established to describe the symbol decoding errors between interusers, based on which a close form expression for theoretical Bit Error Rate (BER) performance of the scheme is derived to analyze the influence of the interuser decoding errors on the BER performance of the scheme. Then simulation is complimented to verify the analytic result above, which also shows that the BER performance of DSTBC-MC-CDMA outgoes that of non-cooperative MC-CDMA with considerable gains. Further- more, the simulations coincide with the theoretical results well.展开更多
In [1], the authors have proposed one high rate transmission scheme for Space-Time Block Codes (STBC) without additional system source such as power, bandwidth and time slot. To maintain the full rank property of the ...In [1], the authors have proposed one high rate transmission scheme for Space-Time Block Codes (STBC) without additional system source such as power, bandwidth and time slot. To maintain the full rank property of the coding gain matrix, we propose a set of STBCs for 4 transmit antennas transmission to transmit one additional information bit achieving rate-9/8. Another orthogonal STBC code with rate-1 is proposed in this paper within the set. It shows by computer simulation results that by employing the set of STBCs, it achieves better bit error rate (BER) performance and?throughput than that of [1] with a valid BER improvement at the high SNR region above 20dB.展开更多
The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all co...The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all considered. Our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power subject to the maximum transmit power of each remote antenna constraint and Qo S(target BER) requirement. According to the definition of EE and using the upper bound of average EE,the optimized objective function is provided. Based on this,utilizing Karush-KuhnTucker conditions and numerical calculation,a suboptimal energy efficient power allocation(PA) scheme is developed,and the closedform expression of PA coefficients is derived. The scheme may obtain the EE performance close to the existing optimal scheme. Moreover,it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Simulation results show the presented scheme is valid and can meet the target BER requirement,and the EE can be increased as target BER requirement decreases.展开更多
针对协作通信系统中源到中继及中继到目的两阶段的瞬时信道状态信息(CSI)影响系统整体误码率(BER)的问题,提出一种综合衡量两阶段信道系数的中继选择方案。首先,根据每个候选中继的CSI,比较源到中继及中继到目的的两阶段信道系数,选出...针对协作通信系统中源到中继及中继到目的两阶段的瞬时信道状态信息(CSI)影响系统整体误码率(BER)的问题,提出一种综合衡量两阶段信道系数的中继选择方案。首先,根据每个候选中继的CSI,比较源到中继及中继到目的的两阶段信道系数,选出两者中较差的信道状态;然后,按照较差的信道状态对候选中继排序,得到近似较优的中继节点集合;最后,从中选择两阶段信道系数之和最大者作为被选中继参与协作传输。仿真结果表明,当候选中继节点数为100及5,BER下降到10-4及10-5时,所提的中继选择方案与基于最优较差信道的中继选择方案、基于最近邻关系的中继选择方案相比,所需信噪比(SNR)分别降低了0.4 d B和0.2 d B。所提方案能够增加无线中继网络的信息传输范围,提高信息传输的可靠性。展开更多
基金Supported by the National High Technology Research and Development Programme of China(No.2014AA01A705)the National Natural Science Foundation of China(U1204607)
文摘In order to improve the bit error rate(BER) performance of turbo codes with short frame size at a wide range of signal to noise ratio(SNR),a new method by optimizing the bit energy is proposed.At first,a formula derived from the Union Bound is introduced.It describes the relations between the bit error rate distribution and the minimum weight distribution.And then,by mathematically optimizing the formula,the energy for every bit of the codeword is optimized to achieve the minimum BER at high SNR region.At last,an adjustable parameter is employed to compensate the degradations of BER at low and moderate SNR regions.Case studies indicate that the improvements of BER for turbo codes with short frame size are significant at a wide range of SNR.
基金the National Natural Science Foundation of China(No.60132030,60572147)the 111 Project(B08033).
文摘There are considerable literatures on the Bit Error Rate(BER)evaluation of DifferentialDetection of Gaussian Minimum Shift Keying(DDGMSK)system using Decision Feedback(DF),butmost of them give the performance based on the Monte Carlo Error Counting(MCEC)technique.Fromthe probability distribution of the phase angle between two vectors perturbed by Gaussian noises,theformulae of BER are derived for the performance analysis of DDGMSK system with DF in this letter.Considering the m-bit dock-tailed sequence,the new formulae of Gaussian Minimum Shift Keying(GMSK)modulated phase and the Time-Varying Signal to Noise Ratio(TVSNR)of the demodulatedsignal are presented,and it is proved that the relationship between the TVSNR of the demodulatedsignal and the size of eye opening is not inevitable.Simulation results show that the theoretical in-vestigation gives analogous results with the MCEC technique.The formulae presented are useful for theperformance analysis of systems using GMSK as modulating and demodulating method,for instance,the analysis of synchronous performance of frequency-hopping communication system.
文摘In recent times, there has been growing interests in integration of voice, data and video traffic in wireless communication networks. With these growing interests, WCDMA has immerged as an attractive access technique. The performance of WCDMA system is deteriorated in presence of multipath fading environment. The paper presents space-time coded minimum mean square error (MMSE) Decision Feedback Equalizer (DFE) for wideband code division multiple access (WCDMA) in a frequency selective channel. The filter coefficients in MMSE DFE are optimized to suppress noise, intersymbol interference (ISI), and multiple access interference (MAI) with reasonable system complexity. For the above structure, we have presented the estimation of BER for a MMSE DFE using computer simulation experiments. The simulation includes the effects of additive white Gaussian noise, multipath fading and multiple access interference (MAI). Furthermore, the performance is compared with standard linear equalizer (LE) and RAKE receiver. Numerical and simulation results show that the MMSE DFE exhibits significant performance improvement over the standard linear equalizer (LE) and RAKE receiver.
基金Supported by the National Natural Science Foundation of China (No.60372107).
文摘A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels with multiple single-antenna users. And an analytical error model is established to describe the symbol decoding errors between interusers, based on which a close form expression for theoretical Bit Error Rate (BER) performance of the scheme is derived to analyze the influence of the interuser decoding errors on the BER performance of the scheme. Then simulation is complimented to verify the analytic result above, which also shows that the BER performance of DSTBC-MC-CDMA outgoes that of non-cooperative MC-CDMA with considerable gains. Further- more, the simulations coincide with the theoretical results well.
文摘In [1], the authors have proposed one high rate transmission scheme for Space-Time Block Codes (STBC) without additional system source such as power, bandwidth and time slot. To maintain the full rank property of the coding gain matrix, we propose a set of STBCs for 4 transmit antennas transmission to transmit one additional information bit achieving rate-9/8. Another orthogonal STBC code with rate-1 is proposed in this paper within the set. It shows by computer simulation results that by employing the set of STBCs, it achieves better bit error rate (BER) performance and?throughput than that of [1] with a valid BER improvement at the high SNR region above 20dB.
基金partially supported by National Natural Science Foundation of China (61571225)Research Founding of Graduate Innovation Center in NUAA (kfjj20150410)+4 种基金the Fundamental Research Funds for the Central Universities (NS2015046,NS2016044)Shenzhen Strategic Emerging Industry Development Funds (JSGG20150331160845693)Qing Lan Project of JiangsuSix Talent Peaks Project in Jiangsu (DZXX-007)Open Research Fund of National Mobile Communications Research Laboratory of Southeast University (2012D17)
文摘The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all considered. Our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power subject to the maximum transmit power of each remote antenna constraint and Qo S(target BER) requirement. According to the definition of EE and using the upper bound of average EE,the optimized objective function is provided. Based on this,utilizing Karush-KuhnTucker conditions and numerical calculation,a suboptimal energy efficient power allocation(PA) scheme is developed,and the closedform expression of PA coefficients is derived. The scheme may obtain the EE performance close to the existing optimal scheme. Moreover,it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Simulation results show the presented scheme is valid and can meet the target BER requirement,and the EE can be increased as target BER requirement decreases.
文摘针对协作通信系统中源到中继及中继到目的两阶段的瞬时信道状态信息(CSI)影响系统整体误码率(BER)的问题,提出一种综合衡量两阶段信道系数的中继选择方案。首先,根据每个候选中继的CSI,比较源到中继及中继到目的的两阶段信道系数,选出两者中较差的信道状态;然后,按照较差的信道状态对候选中继排序,得到近似较优的中继节点集合;最后,从中选择两阶段信道系数之和最大者作为被选中继参与协作传输。仿真结果表明,当候选中继节点数为100及5,BER下降到10-4及10-5时,所提的中继选择方案与基于最优较差信道的中继选择方案、基于最近邻关系的中继选择方案相比,所需信噪比(SNR)分别降低了0.4 d B和0.2 d B。所提方案能够增加无线中继网络的信息传输范围,提高信息传输的可靠性。
