We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayle...We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayleigh fading channel is assumed throughout this work. Various constellations and mapping techniques are considered in this work to maximize the capacity difference between the main channel and the eavesdropper channel, rather than to opti- mize the capacity of both channels. We show that in terms of achievable secrecy rate, Gray and Quasi-Gray mappings only perform Well at low SNR but outperformed by other mapping techniques when SNR increases. The proper design of signal mapping can significantly enhance the achievable secrecy rate in BICM schemes. It is indicated that the key parameter to the secrecy rate of a BICM system is the distance spectrum of Euclidean distances for mappings.展开更多
Multilevel coding(MLC)is a commonly used polar coded modulation scheme,but challenging to implement in engineering due to its high complexity and long decoding delay for high-order modulations.To address these limitat...Multilevel coding(MLC)is a commonly used polar coded modulation scheme,but challenging to implement in engineering due to its high complexity and long decoding delay for high-order modulations.To address these limitations,a novel two-level serially concatenated MLC scheme,in which the bitlevels with similar reliability are bundled and transmitted together,is proposed.The proposed scheme hierarchically protects the two bit-level sets:the bitlevel sets at the higher level are sufficiently reliable and do not require excessive resources for protection,whereas only the bit-level sets at the lower level are encoded by polar codes.The proposed scheme has the advantages of low power consumption,low delay and high reliability.Moreover,an optimized constellation signal labeling rule that can enhance the performance is proposed.Finally,the superiority of the proposed scheme is validated through the theoretical analysis and simulation results.Compared with the bit interleaving coding modulation(BICM)scheme,under 256-quadrature amplitude modulation(QAM),the proposed scheme attains a performance gain of 1.0 dB while reducing the decoding complexity by 54.55%.展开更多
This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID ...This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID scheme, the information bits conveyed by the signal-domain(SiD) symbols and the spatial-domain(SpD) light emitting diode(LED)-index patterns are coded by a protograph low-density parity-check(P-LDPC) code. Specifically, we propose a signal-domain symbol expanding and re-allocating(SSER) method for constructing a type of novel generalized spatial modulation(GSM) constellations, referred to as SSERGSM constellations, so as to boost the performance of the BICGSM-ID MIMO-VLC systems.Moreover, by applying a modified PEXIT(MPEXIT) algorithm, we further design a family of rate-compatible P-LDPC codes, referred to as enhanced accumulate-repeat-accumulate(EARA) codes,which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Both analysis and simulation results illustrate that the proposed SSERGSM constellations and P-LDPC codes can remarkably improve the convergence and decoding performance of MIMO-VLC systems. Therefore, the proposed P-LDPC-coded SSERGSM-mapped BICGSMID configuration is envisioned as a promising transmission solution to satisfy the high-throughput requirement of MIMO-VLC applications.展开更多
Optimization of mapping rule of bit-interleaved Turbo coded modulation with 16 quadrature amplitude modulation (QAM) is investigated based on different impacts of various encoded bits sequence on Turbo decoding perfor...Optimization of mapping rule of bit-interleaved Turbo coded modulation with 16 quadrature amplitude modulation (QAM) is investigated based on different impacts of various encoded bits sequence on Turbo decoding performance. Furthermore, bit-interleaved in-phase and quadrature phase (I-Q) Turbo coded modulation scheme are designed similarly with I-Q trellis coded modulation (TCM). Through performance evaluation and analysis, it can be seen that the novel mapping rule outperforms traditional one and the I-Q Turbo coded modulation can not achieve good performance as expected. Therefore, there is not obvious advantage in using I-Q method in bit-interleaved Turbo coded modulation.展开更多
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon...In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.展开更多
Faster-than-Nyquist(FTN)signaling can improve the spectrum efficiency(SE)of the transmission system.In this paper,we propose a coded modulation FTN(CM-FTN)transmission scheme with precoder and channel shortening(CS)op...Faster-than-Nyquist(FTN)signaling can improve the spectrum efficiency(SE)of the transmission system.In this paper,we propose a coded modulation FTN(CM-FTN)transmission scheme with precoder and channel shortening(CS)optimization to improve bit error rate(BER)performance and reduce the complexity of FTN equalizer.In our proposal,the information rate(IR)or spectral efficiency(SE)is employed and verified as a better performance metric for CM-FTN than the minimum Euclidian distance(MED).The precoder of CM-FTN is optimized for maximizing the IR criterion using the bare-bones particle swarm optimization(BB-PSO)algorithm.Further,a three-carrier CM-FTN system model is used to capture the broadening effect of precoder.Also targeting for the IR maximization,the inter-symbol interference(ISI)length for CS is optimized to reduce the receiver complexity without performance loss.Simulation results demonstrate that our method has a 0.6dB precoding gain compared with the nonprecoding scheme and a maximum of 87.5%of the complexity of FTN equalizer is reduced without BER loss.展开更多
To provide reliability in distributed systems,combination property(CP)is desired,where k original packets are encoded into n≥k packets and arbitrary k are sufficient to reconstruct all the original packets.Shift-and-...To provide reliability in distributed systems,combination property(CP)is desired,where k original packets are encoded into n≥k packets and arbitrary k are sufficient to reconstruct all the original packets.Shift-and-add(SA)encoding combined with zigzag decoding(ZD)obtains the CP-ZD,which is promising to reap low computational complexity in the encoding/decoding process of these systems.As densely coded modulation is difficult to achieve CP-ZD,research attentions are paid to sparse coded modulation.The drawback of existing sparse CP-ZD coded modulation lies in high overhead,especially in widely deployed setting m<k,where m≜n−k.For this scenario,namely,m<k,a sparse reverseorder shift(Rev-Shift)CP-ZD coded modulation is designed.The proof that Rev-Shift possesses CP-ZD is provided.A lower bound for the overhead,as far as we know is the first for sparse CP-ZD coded modulation,is derived.The bound is found tight in certain scenarios,which shows the code optimality.Extensive numerical studies show that compared to existing sparse CP-ZD coded modulation,the overhead of Rev-Shift reduces significantly,and the derived lower bound is tight when k or m approaches 0.展开更多
Orthogonal time frequency space(OTFS)modulation is a novel two-dimensional modulation scheme for high-Doppler fading scenarios,which is implemented in the delay-Doppler(DD)domain.In time and frequency selective channe...Orthogonal time frequency space(OTFS)modulation is a novel two-dimensional modulation scheme for high-Doppler fading scenarios,which is implemented in the delay-Doppler(DD)domain.In time and frequency selective channels,OTFS modulation is more robust than the popular orthogonal frequency division multiplexing(OFDM)modulation technique.To further improve transmission reliability,some channel coding schemes are used in the OTFS modulation system.In this paper,the coded OTFS modulation system is considered and introduced in detail.Furthermore,the performance of the uncoded/coded OTFS system and OFDM system is analyzed with different relative speeds,modulation schemes,and iterations.Simulation results show that the OTFS system has the potential of full diversity gain and better robustness under high mobility scenarios.展开更多
This paper proposes a high-throughput short reference differential chaos shift keying cooperative communication system with the aid of code index modulation,referred to as CIM-SR-DCSK-CC system.In the proposed CIM-SR-...This paper proposes a high-throughput short reference differential chaos shift keying cooperative communication system with the aid of code index modulation,referred to as CIM-SR-DCSK-CC system.In the proposed CIM-SR-DCSK-CC system,the source transmits information bits to both the relay and destination in the first time slot,while the relay not only forwards the source information bits but also sends new information bits to the destination in the second time slot.To be specific,the relay employs an N-order Walsh code to carry additional log_(2)N information bits,which are superimposed onto the SRDCSK signal carrying the decoded source information bits.Subsequently,the superimposed signal carrying both the source and relay information bits is transmitted to the destination.Moreover,the theoretical bit error rate(BER)expressions of the proposed CIMSR-DCSK-CC system are derived over additive white Gaussian noise(AWGN)and multipath Rayleigh fading channels.Compared with the conventional DCSKCC system and SR-DCSK-CC system,the proposed CIM-SR-DCSK-CC system can significantly improve the throughput without deteriorating any BER performance.As a consequence,the proposed system is very promising for the applications of the 6G-enabled lowpower and high-rate communication.展开更多
Iterative demodulation and decoding scheme is analyzed and modulation labeling is considered to be one of the crucial factors to this scheme. By analyzing the existent mapping design criterion, four aspects are found ...Iterative demodulation and decoding scheme is analyzed and modulation labeling is considered to be one of the crucial factors to this scheme. By analyzing the existent mapping design criterion, four aspects are found as the key techniques for choosing a label mapping. Based on this discovery, a novel mapping design criteflon is proposed and two label mappings are searched according to it. Simulation results show that the performance of BICM-ID using the novel mappings is better than the former ones. The extrinsic information transfer （EXIT） chart is introduced and it is used to evaluate the proposed mapping design criteria.展开更多
Performance of the Adaptive Coding and Modulation(ACM) strongly depends on the retrieved Channel State Information(CSI),which can be obtained using the channel estimation techniques relying on pilot symbol transmissio...Performance of the Adaptive Coding and Modulation(ACM) strongly depends on the retrieved Channel State Information(CSI),which can be obtained using the channel estimation techniques relying on pilot symbol transmission.Earlier analysis of methods of pilot-aided channel estimation for ACM systems were relatively little.In this paper,we investigate the performance of CSI prediction using the Minimum Mean Square Error(MMSE)channel estimator for an ACM system.To solve the two problems of MMSE:high computational operations and oversimplified assumption,we then propose the Low-Complexity schemes(LC-MMSE and Recursion LC-MMSE(R-LC-MMSE)).Computational complexity and Mean Square Error(MSE) are presented to evaluate the efficiency of the proposed algorithm.Both analysis and numerical results show that LC-MMSE performs close to the wellknown MMSE estimator with much lower complexity and R-LC-MMSE improves the application of MMSE estimation to specific circumstances.展开更多
Satellite communication develops rapidly due to its global coverage and is unrestricted to the ground environment. However, compared with the traditional ground TCP/IP network, a satellite-to-ground link has a more ex...Satellite communication develops rapidly due to its global coverage and is unrestricted to the ground environment. However, compared with the traditional ground TCP/IP network, a satellite-to-ground link has a more extensive round trip time(RTT) and a higher packet loss rate,which takes more time in error recovery and wastes precious channel resources. Forward error correction(FEC) is a coding method that can alleviate bit error and packet loss, but how to achieve high throughput in the dynamic network environment is still a significant challenge. Inspired by the deep learning technique, this paper proposes a signal-to-noise ratio(SNR) based adaptive coding modulation method. This method can maximize channel utilization while ensuring communication quality and is suitable for satellite-to-ground communication scenarios where the channel state changes rapidly. We predict the SNR using the long short-term memory(LSTM) network that considers the past channel status and real-time global weather. Finally, we use the optimal matching rate(OMR) to evaluate the pros and cons of each method quantitatively. Extensive simulation results demonstrate that our proposed LSTM-based method outperforms the state-of-the-art prediction algorithms significantly in mean absolute error(MAE). Moreover, it leads to the least spectrum waste.展开更多
Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Vi...Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.展开更多
传统的码索引调制(code index modulation,CIM)系统仅通过扩频码和星座符号来承载信息,能量效率和频谱效率都较低,而附加相位作为一种独特的调制符号来承载信息,具有低传输功耗的特点。为了充分利用多天线索引来提高频谱效率,提出了基...传统的码索引调制(code index modulation,CIM)系统仅通过扩频码和星座符号来承载信息,能量效率和频谱效率都较低,而附加相位作为一种独特的调制符号来承载信息,具有低传输功耗的特点。为了充分利用多天线索引来提高频谱效率,提出了基于低功耗设计的高速率广义空间码索引调制(high-rate generalized space code index modulation,HR-GS-CIM)系统。HR-GS-CIM系统通过使用附加相位替代传统的调制符号,并且通过遗传算法(genetic algorithm,GA)来优化设计附加相位,展现了极高的能效优势和性能优势。同时,HR-GS-CIM系统通过引入广义和空间索引的方法,将附加相位、扩频码以及天线索引进行联合映射选择,并采用低复杂度的联合映射选择算法,极大地提高了系统频谱效率。此外,分析了HR-GS-CIM系统的理论性能,并且仿真验证了HR-GS-CIM系统的理论和仿真性能一致。最后,与传统的CIM系统等对比,验证了所提HR-GS-CIM系统具有显著的性能增益。展开更多
为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符...为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符,有利于通讯的连续性检测。创建TLINK(Transmit Link)、BLINK(Back Link)的K码控制字符,其中TLINK控制字符在Serdes的发送端进行定期发送,接收端收到TLINK控制字符后,控制本方的Serdes发送端优先输出BLINK控制字符进行应答,以建立通讯双方之间的握手关系,有利于通讯的超时和状态检测。校验独立于SOF、EOF之间的用户数据,进行CRC32(Cyclic Redundancy Check32)计算,有利于通讯的误码检测。实验结果表明,该协议可实现对Serdes链路的丢帧数量、误码数量、超时数量及通讯断开时长进行准确监控,最小时间精度为10μs。展开更多
文摘We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayleigh fading channel is assumed throughout this work. Various constellations and mapping techniques are considered in this work to maximize the capacity difference between the main channel and the eavesdropper channel, rather than to opti- mize the capacity of both channels. We show that in terms of achievable secrecy rate, Gray and Quasi-Gray mappings only perform Well at low SNR but outperformed by other mapping techniques when SNR increases. The proper design of signal mapping can significantly enhance the achievable secrecy rate in BICM schemes. It is indicated that the key parameter to the secrecy rate of a BICM system is the distance spectrum of Euclidean distances for mappings.
基金supported by the External Cooperation Program of Science and Technology of Fujian Province,China(2024I0016)the Fundamental Research Funds for the Central Universities(ZQN-1005).
文摘Multilevel coding(MLC)is a commonly used polar coded modulation scheme,but challenging to implement in engineering due to its high complexity and long decoding delay for high-order modulations.To address these limitations,a novel two-level serially concatenated MLC scheme,in which the bitlevels with similar reliability are bundled and transmitted together,is proposed.The proposed scheme hierarchically protects the two bit-level sets:the bitlevel sets at the higher level are sufficiently reliable and do not require excessive resources for protection,whereas only the bit-level sets at the lower level are encoded by polar codes.The proposed scheme has the advantages of low power consumption,low delay and high reliability.Moreover,an optimized constellation signal labeling rule that can enhance the performance is proposed.Finally,the superiority of the proposed scheme is validated through the theoretical analysis and simulation results.Compared with the bit interleaving coding modulation(BICM)scheme,under 256-quadrature amplitude modulation(QAM),the proposed scheme attains a performance gain of 1.0 dB while reducing the decoding complexity by 54.55%.
基金supported in part by the NSF of China under Grant 62322106,62071131the Guangdong Basic and Applied Basic Research Foundation under Grant 2022B1515020086+2 种基金the International Collaborative Research Program of Guangdong Science and Technology Department under Grant 2022A0505050070in part by the Open Research Fund of the State Key Laboratory of Integrated Services Networks under Grant ISN22-23the National Research Foundation,Singapore University of Technology Design under its Future Communications Research&Development Programme“Advanced Error Control Coding for 6G URLLC and mMTC”Grant No.FCP-NTU-RG-2022-020.
文摘This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID scheme, the information bits conveyed by the signal-domain(SiD) symbols and the spatial-domain(SpD) light emitting diode(LED)-index patterns are coded by a protograph low-density parity-check(P-LDPC) code. Specifically, we propose a signal-domain symbol expanding and re-allocating(SSER) method for constructing a type of novel generalized spatial modulation(GSM) constellations, referred to as SSERGSM constellations, so as to boost the performance of the BICGSM-ID MIMO-VLC systems.Moreover, by applying a modified PEXIT(MPEXIT) algorithm, we further design a family of rate-compatible P-LDPC codes, referred to as enhanced accumulate-repeat-accumulate(EARA) codes,which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Both analysis and simulation results illustrate that the proposed SSERGSM constellations and P-LDPC codes can remarkably improve the convergence and decoding performance of MIMO-VLC systems. Therefore, the proposed P-LDPC-coded SSERGSM-mapped BICGSMID configuration is envisioned as a promising transmission solution to satisfy the high-throughput requirement of MIMO-VLC applications.
文摘Optimization of mapping rule of bit-interleaved Turbo coded modulation with 16 quadrature amplitude modulation (QAM) is investigated based on different impacts of various encoded bits sequence on Turbo decoding performance. Furthermore, bit-interleaved in-phase and quadrature phase (I-Q) Turbo coded modulation scheme are designed similarly with I-Q trellis coded modulation (TCM). Through performance evaluation and analysis, it can be seen that the novel mapping rule outperforms traditional one and the I-Q Turbo coded modulation can not achieve good performance as expected. Therefore, there is not obvious advantage in using I-Q method in bit-interleaved Turbo coded modulation.
基金supported by National Natural Science Foundation of China(No.61571061)
文摘In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.
基金This work was supported by National Natural Science Foundation of China(No.61961014).
文摘Faster-than-Nyquist(FTN)signaling can improve the spectrum efficiency(SE)of the transmission system.In this paper,we propose a coded modulation FTN(CM-FTN)transmission scheme with precoder and channel shortening(CS)optimization to improve bit error rate(BER)performance and reduce the complexity of FTN equalizer.In our proposal,the information rate(IR)or spectral efficiency(SE)is employed and verified as a better performance metric for CM-FTN than the minimum Euclidian distance(MED).The precoder of CM-FTN is optimized for maximizing the IR criterion using the bare-bones particle swarm optimization(BB-PSO)algorithm.Further,a three-carrier CM-FTN system model is used to capture the broadening effect of precoder.Also targeting for the IR maximization,the inter-symbol interference(ISI)length for CS is optimized to reduce the receiver complexity without performance loss.Simulation results demonstrate that our method has a 0.6dB precoding gain compared with the nonprecoding scheme and a maximum of 87.5%of the complexity of FTN equalizer is reduced without BER loss.
基金supported by research grants from Natural Science Foundation of China(62071304)Guangdong Basic and Applied Basic Research Foundation(2020A1515010381,2022A1515011219,20220809155455002)+2 种基金Basic Research foundation of Shenzhen City(20200826152915001,20190808120415286)Natural Science Foundation of Shenzhen University(00002501)Xinjiang Uygur Autonomous Region Natural Science Foundation General Project(2023D01A60).
文摘To provide reliability in distributed systems,combination property(CP)is desired,where k original packets are encoded into n≥k packets and arbitrary k are sufficient to reconstruct all the original packets.Shift-and-add(SA)encoding combined with zigzag decoding(ZD)obtains the CP-ZD,which is promising to reap low computational complexity in the encoding/decoding process of these systems.As densely coded modulation is difficult to achieve CP-ZD,research attentions are paid to sparse coded modulation.The drawback of existing sparse CP-ZD coded modulation lies in high overhead,especially in widely deployed setting m<k,where m≜n−k.For this scenario,namely,m<k,a sparse reverseorder shift(Rev-Shift)CP-ZD coded modulation is designed.The proof that Rev-Shift possesses CP-ZD is provided.A lower bound for the overhead,as far as we know is the first for sparse CP-ZD coded modulation,is derived.The bound is found tight in certain scenarios,which shows the code optimality.Extensive numerical studies show that compared to existing sparse CP-ZD coded modulation,the overhead of Rev-Shift reduces significantly,and the derived lower bound is tight when k or m approaches 0.
基金supported in part by the National Natural Science Founda⁃tion of China under Grant No.61771364,and by the National Key R&D Pro⁃gram of China under Grant No.2020YEB1807104.
文摘Orthogonal time frequency space(OTFS)modulation is a novel two-dimensional modulation scheme for high-Doppler fading scenarios,which is implemented in the delay-Doppler(DD)domain.In time and frequency selective channels,OTFS modulation is more robust than the popular orthogonal frequency division multiplexing(OFDM)modulation technique.To further improve transmission reliability,some channel coding schemes are used in the OTFS modulation system.In this paper,the coded OTFS modulation system is considered and introduced in detail.Furthermore,the performance of the uncoded/coded OTFS system and OFDM system is analyzed with different relative speeds,modulation schemes,and iterations.Simulation results show that the OTFS system has the potential of full diversity gain and better robustness under high mobility scenarios.
基金supported in part by the NSF of China under Grant 62322106,62071131 and 62171135the Guangdong Basic and Applied Basic Research Foundation under Grant 2022B1515020086+2 种基金the NSF of Guangdong Province under Grant 2019A1515011465the International Collaborative Research Program of Guangdong Science and Technology Department under Grant 2022A0505050070the Industrial R&D Project of Haoyang Electronic Co.,Ltd.under Grant 2022440002001494.
文摘This paper proposes a high-throughput short reference differential chaos shift keying cooperative communication system with the aid of code index modulation,referred to as CIM-SR-DCSK-CC system.In the proposed CIM-SR-DCSK-CC system,the source transmits information bits to both the relay and destination in the first time slot,while the relay not only forwards the source information bits but also sends new information bits to the destination in the second time slot.To be specific,the relay employs an N-order Walsh code to carry additional log_(2)N information bits,which are superimposed onto the SRDCSK signal carrying the decoded source information bits.Subsequently,the superimposed signal carrying both the source and relay information bits is transmitted to the destination.Moreover,the theoretical bit error rate(BER)expressions of the proposed CIMSR-DCSK-CC system are derived over additive white Gaussian noise(AWGN)and multipath Rayleigh fading channels.Compared with the conventional DCSKCC system and SR-DCSK-CC system,the proposed CIM-SR-DCSK-CC system can significantly improve the throughput without deteriorating any BER performance.As a consequence,the proposed system is very promising for the applications of the 6G-enabled lowpower and high-rate communication.
文摘Iterative demodulation and decoding scheme is analyzed and modulation labeling is considered to be one of the crucial factors to this scheme. By analyzing the existent mapping design criterion, four aspects are found as the key techniques for choosing a label mapping. Based on this discovery, a novel mapping design criteflon is proposed and two label mappings are searched according to it. Simulation results show that the performance of BICM-ID using the novel mappings is better than the former ones. The extrinsic information transfer （EXIT） chart is introduced and it is used to evaluate the proposed mapping design criteria.
基金supported by the 2011 China Aerospace Science and Technology Foundationthe Certain Ministry Foundation under Grant No.20212HK03010
文摘Performance of the Adaptive Coding and Modulation(ACM) strongly depends on the retrieved Channel State Information(CSI),which can be obtained using the channel estimation techniques relying on pilot symbol transmission.Earlier analysis of methods of pilot-aided channel estimation for ACM systems were relatively little.In this paper,we investigate the performance of CSI prediction using the Minimum Mean Square Error(MMSE)channel estimator for an ACM system.To solve the two problems of MMSE:high computational operations and oversimplified assumption,we then propose the Low-Complexity schemes(LC-MMSE and Recursion LC-MMSE(R-LC-MMSE)).Computational complexity and Mean Square Error(MSE) are presented to evaluate the efficiency of the proposed algorithm.Both analysis and numerical results show that LC-MMSE performs close to the wellknown MMSE estimator with much lower complexity and R-LC-MMSE improves the application of MMSE estimation to specific circumstances.
基金supported by the National High Technology Research and Development Program of China (No. 2020YFB1806004)。
文摘Satellite communication develops rapidly due to its global coverage and is unrestricted to the ground environment. However, compared with the traditional ground TCP/IP network, a satellite-to-ground link has a more extensive round trip time(RTT) and a higher packet loss rate,which takes more time in error recovery and wastes precious channel resources. Forward error correction(FEC) is a coding method that can alleviate bit error and packet loss, but how to achieve high throughput in the dynamic network environment is still a significant challenge. Inspired by the deep learning technique, this paper proposes a signal-to-noise ratio(SNR) based adaptive coding modulation method. This method can maximize channel utilization while ensuring communication quality and is suitable for satellite-to-ground communication scenarios where the channel state changes rapidly. We predict the SNR using the long short-term memory(LSTM) network that considers the past channel status and real-time global weather. Finally, we use the optimal matching rate(OMR) to evaluate the pros and cons of each method quantitatively. Extensive simulation results demonstrate that our proposed LSTM-based method outperforms the state-of-the-art prediction algorithms significantly in mean absolute error(MAE). Moreover, it leads to the least spectrum waste.
基金supported by the National Natural Science Foundation of China(61302095,61401165)the Natural Science Foundation of Fujian Province of China(2014J01243,2014J05076,2015J01262)the Huaqiao University Science Foundation(13Y0384)
文摘Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.
文摘传统的码索引调制(code index modulation,CIM)系统仅通过扩频码和星座符号来承载信息,能量效率和频谱效率都较低,而附加相位作为一种独特的调制符号来承载信息,具有低传输功耗的特点。为了充分利用多天线索引来提高频谱效率,提出了基于低功耗设计的高速率广义空间码索引调制(high-rate generalized space code index modulation,HR-GS-CIM)系统。HR-GS-CIM系统通过使用附加相位替代传统的调制符号,并且通过遗传算法(genetic algorithm,GA)来优化设计附加相位,展现了极高的能效优势和性能优势。同时,HR-GS-CIM系统通过引入广义和空间索引的方法,将附加相位、扩频码以及天线索引进行联合映射选择,并采用低复杂度的联合映射选择算法,极大地提高了系统频谱效率。此外,分析了HR-GS-CIM系统的理论性能,并且仿真验证了HR-GS-CIM系统的理论和仿真性能一致。最后,与传统的CIM系统等对比,验证了所提HR-GS-CIM系统具有显著的性能增益。
