With rapid development of unmanned aerial vehicles(UAVs), more and more UAVs access satellite networks for data transmission. To improve the spectral efficiency, non-orthogonal multiple access(NOMA) is adopted to inte...With rapid development of unmanned aerial vehicles(UAVs), more and more UAVs access satellite networks for data transmission. To improve the spectral efficiency, non-orthogonal multiple access(NOMA) is adopted to integrate UAVs into the satellite network, where multiple satellites cooperatively serve the UAVs and mobile terminal using the Ku-band and above. Taking into account the rain fading and the fading correlation, the outage performance is first analytically obtained for fixed power allocation and then efficiently calculated by the proposed power allocation algorithm to guarantee the user fairness. Simulation results verify the outage performance analysis and show the performance improvement of the proposed power allocation scheme.展开更多
Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these adv...Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these advancements, efficiently programming GPUs remains a daunting challenge, often relying on trial-and-error optimization methods. This paper introduces an optimization technique for CUDA programs through a novel Data Layout strategy, aimed at restructuring memory data arrangement to significantly enhance data access locality. Focusing on the dynamic programming algorithm for chained matrix multiplication—a critical operation across various domains including artificial intelligence (AI), high-performance computing (HPC), and the Internet of Things (IoT)—this technique facilitates more localized access. We specifically illustrate the importance of efficient matrix multiplication in these areas, underscoring the technique’s broader applicability and its potential to address some of the most pressing computational challenges in GPU-accelerated applications. Our findings reveal a remarkable reduction in memory consumption and a substantial 50% decrease in execution time for CUDA programs utilizing this technique, thereby setting a new benchmark for optimization in GPU computing.展开更多
针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, suc...针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, successive interference cancellation)和信道状态信息(CSI, channel state information)实际情况,研究系统在采用理想、时间开关(TS, time switching)和功率分割(PS, power splitting)3种中继传输方案时次用户的中断性能。推导出次用户中断概率的解析表达式,并通过蒙特卡洛仿真验证理论推导的正确性。实验结果表明,非理想SIC和CSI会导致次用户的中断性能下降,相对于非理想CSI,非理想SIC给系统中断性能带来的损失更大。此外,用户采用PS中继传输方案的中断概率比采用TS方案低,当改变非理想SIC和CSI因子时,采用PS方案用户的中断概率差值比TS方案小,说明PS中继传输方案的可靠性优于TS方案。展开更多
发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在L...发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在LAS CDMA中仿真了其性能,并与传统CDMA进行了比较。表明发射分集与 LAS CDMA相结合能充分的发挥两者的优越特性。展开更多
This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>...This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>∞</sub> </span>performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified.展开更多
研究了基于无线携能通信(SWIPT,simultaneous wireless information and power transfer)和非正交多址接入(NOMA,non-orthogonal multiple access)的认知中继网络的中断性能。针对具有直接链路通信和两阶段通信两种传输模式,推导了系统...研究了基于无线携能通信(SWIPT,simultaneous wireless information and power transfer)和非正交多址接入(NOMA,non-orthogonal multiple access)的认知中继网络的中断性能。针对具有直接链路通信和两阶段通信两种传输模式,推导了系统总体中断概率的解析表达式和高信噪比条件下的渐近表达式,并通过Monte-Carlo仿真验证了理论推导的正确性。仿真结果表明,系统在直接通信模式下能获得更好的中断性能。此外,与传统的正交多址接入认知中继网络相比,基于SWIPT-NOMA的认知中继网络能获得更好的中断性能和更高的能量效率。展开更多
Discrete Fourier transform-spread generalized multi-carrier （DFT-S-GMC） based single carrier-frequency division multiple access （SC-FDMA） scheme is a promising solution for uplink transmission of broadband wireles...Discrete Fourier transform-spread generalized multi-carrier （DFT-S-GMC） based single carrier-frequency division multiple access （SC-FDMA） scheme is a promising solution for uplink transmission of broadband wireless communication. In this paper, the impact of non-perfect orthogonal prototype filter to the performance of the DFT-S-GMC system is discussed. Single sub-band frequency-domain equalization （FDE） method is presented and the performance loss caused by FDE-tone discarding is analyzed. Moreover, the post-processing signal to interference plus noise ratio （SINR） of DFT-S-GMC receiver over multi-path channel is addressed. The theoretical analysis illustrates that the non-perfect orthogonal prototype filter results in inter-symbol interference （ISI） and inter-sub-band interference （IBI）, and the variance of the ISI is still less than le-4 and much larger than that of IBI. By designing proper system parameters, the reconstruction error due to FDE-tones discarding can be controlled under -40 dB; the post-processing SINR of the DFT-S-GMC receiver with minimum mean square error （MMSE） equalization is higher than that with zero forcing （ZF） equalization. The theoretical performances are verified by extensive simulation results.展开更多
基金supported in part by the National Natural Science Foundation of China (No. 91638205, 91438206, 61771286, 61621091)
文摘With rapid development of unmanned aerial vehicles(UAVs), more and more UAVs access satellite networks for data transmission. To improve the spectral efficiency, non-orthogonal multiple access(NOMA) is adopted to integrate UAVs into the satellite network, where multiple satellites cooperatively serve the UAVs and mobile terminal using the Ku-band and above. Taking into account the rain fading and the fading correlation, the outage performance is first analytically obtained for fixed power allocation and then efficiently calculated by the proposed power allocation algorithm to guarantee the user fairness. Simulation results verify the outage performance analysis and show the performance improvement of the proposed power allocation scheme.
文摘Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these advancements, efficiently programming GPUs remains a daunting challenge, often relying on trial-and-error optimization methods. This paper introduces an optimization technique for CUDA programs through a novel Data Layout strategy, aimed at restructuring memory data arrangement to significantly enhance data access locality. Focusing on the dynamic programming algorithm for chained matrix multiplication—a critical operation across various domains including artificial intelligence (AI), high-performance computing (HPC), and the Internet of Things (IoT)—this technique facilitates more localized access. We specifically illustrate the importance of efficient matrix multiplication in these areas, underscoring the technique’s broader applicability and its potential to address some of the most pressing computational challenges in GPU-accelerated applications. Our findings reveal a remarkable reduction in memory consumption and a substantial 50% decrease in execution time for CUDA programs utilizing this technique, thereby setting a new benchmark for optimization in GPU computing.
文摘针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, successive interference cancellation)和信道状态信息(CSI, channel state information)实际情况,研究系统在采用理想、时间开关(TS, time switching)和功率分割(PS, power splitting)3种中继传输方案时次用户的中断性能。推导出次用户中断概率的解析表达式,并通过蒙特卡洛仿真验证理论推导的正确性。实验结果表明,非理想SIC和CSI会导致次用户的中断性能下降,相对于非理想CSI,非理想SIC给系统中断性能带来的损失更大。此外,用户采用PS中继传输方案的中断概率比采用TS方案低,当改变非理想SIC和CSI因子时,采用PS方案用户的中断概率差值比TS方案小,说明PS中继传输方案的可靠性优于TS方案。
文摘发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在LAS CDMA中仿真了其性能,并与传统CDMA进行了比较。表明发射分集与 LAS CDMA相结合能充分的发挥两者的优越特性。
文摘This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>∞</sub> </span>performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified.
文摘研究了基于无线携能通信(SWIPT,simultaneous wireless information and power transfer)和非正交多址接入(NOMA,non-orthogonal multiple access)的认知中继网络的中断性能。针对具有直接链路通信和两阶段通信两种传输模式,推导了系统总体中断概率的解析表达式和高信噪比条件下的渐近表达式,并通过Monte-Carlo仿真验证了理论推导的正确性。仿真结果表明,系统在直接通信模式下能获得更好的中断性能。此外,与传统的正交多址接入认知中继网络相比,基于SWIPT-NOMA的认知中继网络能获得更好的中断性能和更高的能量效率。
基金Supported by the National High-Tech Research & Development Program of China (Grant No. 2006AA01Z280)the National Key Project of China during the 11th Five-Year Plan Period (Grant No. 2009ZX03003-006-03)
文摘Discrete Fourier transform-spread generalized multi-carrier （DFT-S-GMC） based single carrier-frequency division multiple access （SC-FDMA） scheme is a promising solution for uplink transmission of broadband wireless communication. In this paper, the impact of non-perfect orthogonal prototype filter to the performance of the DFT-S-GMC system is discussed. Single sub-band frequency-domain equalization （FDE） method is presented and the performance loss caused by FDE-tone discarding is analyzed. Moreover, the post-processing signal to interference plus noise ratio （SINR） of DFT-S-GMC receiver over multi-path channel is addressed. The theoretical analysis illustrates that the non-perfect orthogonal prototype filter results in inter-symbol interference （ISI） and inter-sub-band interference （IBI）, and the variance of the ISI is still less than le-4 and much larger than that of IBI. By designing proper system parameters, the reconstruction error due to FDE-tones discarding can be controlled under -40 dB; the post-processing SINR of the DFT-S-GMC receiver with minimum mean square error （MMSE） equalization is higher than that with zero forcing （ZF） equalization. The theoretical performances are verified by extensive simulation results.
