针对传统集中式电池均衡电路体积大、不易扩展、均衡精确度低;而分布式均衡电路存在元件多、成本高的问题,提出了一种单电感双向电池均衡电路,该均衡电路采用Buck-Boost变换器与开关矩阵相结合的方式实现对整个电池组的均衡,通过对电感...针对传统集中式电池均衡电路体积大、不易扩展、均衡精确度低;而分布式均衡电路存在元件多、成本高的问题,提出了一种单电感双向电池均衡电路,该均衡电路采用Buck-Boost变换器与开关矩阵相结合的方式实现对整个电池组的均衡,通过对电感的时分复用实现对每一个电池独立均衡控制。均衡电路中电感电流工作于断续模式,消除了各电池之间的交叉影响。研究了该均衡电路的工作模式和控制策略,在此基础上研制了针对4个电池单体的均衡实验电路,均衡实验验证了理论分析的正确性和控制策略的有效性,同时,无论电池组在充电、放电,还是静置状态,该均衡器均能保证均衡精确度在20 m V以内。展开更多
The performance of normalized throughput in wavelength division multiplexing （WDM） based coherent time-spreading optical code division multiple access （TS-OCDMA） system is studied. The upper bound and lower bound ...The performance of normalized throughput in wavelength division multiplexing （WDM） based coherent time-spreading optical code division multiple access （TS-OCDMA） system is studied. The upper bound and lower bound of normalized throughput are obtained with 8 wavelength channels and 127-length Gold code, and with 4 wavelength channels and 511-length Gold code respectively. It is shown that when all simultaneous users are equally allocated to different wavelength channels, WDM＋TS-OCDMA has much better performance. However, if there is no central control to allocate wavelength channels equally, WDM＋TS-OCDMA system has the in-between performance of normalized throughput.展开更多
We extensively discuss 25 Gb/s per wavelength capacity in both IEEE and ITU-T standardization to support the increasing bandwidth requirement. In this Letter, we propose to use the optical dispersion compensation tech...We extensively discuss 25 Gb/s per wavelength capacity in both IEEE and ITU-T standardization to support the increasing bandwidth requirement. In this Letter, we propose to use the optical dispersion compensation technique in an optical line terminal（OLT） combined with a bandwidth-limited electro-absorption modulated laser in an optical network unit to achieve 25 Gb/s capacity for the upstream link. We evaluate the positive and negative dispersion tolerances of 25 Gb/s electrical duo-binary（EDB） and pulse-amplitude modulation（PAM-4） signals. We achieve 39.5 and 31 d B upstream loss budgets for the 25 Gb/s EDB and PAM-4 signals by using-600 and-500 ps∕nm optical dispersion compensation in OLT, respectively, both supporting 0–40 km differential reach.展开更多
The fifth generation(5G)of wireless networks features three core use cases,namely ultra-reliable and low latency communications(URLLC),massive machine type communications(mMTC),and enhanced mobile broadband(eMBB).Thes...The fifth generation(5G)of wireless networks features three core use cases,namely ultra-reliable and low latency communications(URLLC),massive machine type communications(mMTC),and enhanced mobile broadband(eMBB).These use cases co-exist in many practical scenarios and compete for the same set of time and frequency resources,resulting in a natural trade-off in their performance.In this paper,a network supporting both URLLC and eMBB modes of operation is studied.To guarantee the ultra low latency requirement of URLLC,a dynamic resource allocation scheme indicated by a two-dimensional bitmap is proposed.This approach is capable to achieve finer granularity as well as lower false cancellation rate compared to the state-of-the-art methods.A novel power control and indication method is also proposed to dynamically provide different power control parameters to the user equipment(UE),while guaranteeing the reliability requirement of URLLC and minimizing the impact to eMBB.In addition,we devise a dynamic selection mechanism(DSM)to accommodate diverse scenarios,which is empowered with load prediction to become more intelligent.Our extensive system-level simulation results for eMBB-URLLC co-existence scenarios showcase that the perceived throughput of eMBB UEs is increased by 45.3%,while about 13.3% more UEs are enjoying URLLC services with at most 84% transmit power savings compared to the state-of-the-art methods.展开更多
WDM passive optical network becomes more favorable as the required bandwidth increases, but currently few media access control algorithms adapted to WDM acc ess network. This paper presented a new scheduling algorithm...WDM passive optical network becomes more favorable as the required bandwidth increases, but currently few media access control algorithms adapted to WDM acc ess network. This paper presented a new scheduling algorithm for bandwidth shari ng in WDM passive optical networks, which provides per-flow delay guarantee and supports variable-length packets scheduling. Through theoretical analysis and simulation, the end-to-end delay bound and throughput fairness of the algori thm was demonstrated.展开更多
提出了一种临界连续模式(CRM)单电感双输出(SIDO)Buck功率因数校正(PFC)变换器及其控制策略,并分析了其工作特性。通过对电感的分时复用控制,实现了2个输出支路的独立控制。在输入电压接近各输出支路电压情况下,控制器限制了开关管的最...提出了一种临界连续模式(CRM)单电感双输出(SIDO)Buck功率因数校正(PFC)变换器及其控制策略,并分析了其工作特性。通过对电感的分时复用控制,实现了2个输出支路的独立控制。在输入电压接近各输出支路电压情况下,控制器限制了开关管的最小关断时间,解决了工作于CRM时电感在输入电流过零点附近难以分时复用控制的问题,并抑制了电感在输入电流过零点附近的复用频率。相对于传统两级结构的多路输出PFC变换器,CRM SIDO Buck PFC变换器减少了控制器与电感的数量,降低了变换器的体积与成本,并提高了变换器的效率。实验结果验证了所提变换器高效率、高功率因数以及2个输出支路的高输出精度控制特性。展开更多
文摘针对传统集中式电池均衡电路体积大、不易扩展、均衡精确度低;而分布式均衡电路存在元件多、成本高的问题,提出了一种单电感双向电池均衡电路,该均衡电路采用Buck-Boost变换器与开关矩阵相结合的方式实现对整个电池组的均衡,通过对电感的时分复用实现对每一个电池独立均衡控制。均衡电路中电感电流工作于断续模式,消除了各电池之间的交叉影响。研究了该均衡电路的工作模式和控制策略,在此基础上研制了针对4个电池单体的均衡实验电路,均衡实验验证了理论分析的正确性和控制策略的有效性,同时,无论电池组在充电、放电,还是静置状态,该均衡器均能保证均衡精确度在20 m V以内。
基金supported by the National Natural Science Foundation of China under Grant No. 60772027
文摘The performance of normalized throughput in wavelength division multiplexing （WDM） based coherent time-spreading optical code division multiple access （TS-OCDMA） system is studied. The upper bound and lower bound of normalized throughput are obtained with 8 wavelength channels and 127-length Gold code, and with 4 wavelength channels and 511-length Gold code respectively. It is shown that when all simultaneous users are equally allocated to different wavelength channels, WDM＋TS-OCDMA has much better performance. However, if there is no central control to allocate wavelength channels equally, WDM＋TS-OCDMA system has the in-between performance of normalized throughput.
基金supported by the National Natural Science Foundation of China under Grant Nos. 61322507, 61132004, and 61575122
文摘We extensively discuss 25 Gb/s per wavelength capacity in both IEEE and ITU-T standardization to support the increasing bandwidth requirement. In this Letter, we propose to use the optical dispersion compensation technique in an optical line terminal（OLT） combined with a bandwidth-limited electro-absorption modulated laser in an optical network unit to achieve 25 Gb/s capacity for the upstream link. We evaluate the positive and negative dispersion tolerances of 25 Gb/s electrical duo-binary（EDB） and pulse-amplitude modulation（PAM-4） signals. We achieve 39.5 and 31 d B upstream loss budgets for the 25 Gb/s EDB and PAM-4 signals by using-600 and-500 ps∕nm optical dispersion compensation in OLT, respectively, both supporting 0–40 km differential reach.
文摘The fifth generation(5G)of wireless networks features three core use cases,namely ultra-reliable and low latency communications(URLLC),massive machine type communications(mMTC),and enhanced mobile broadband(eMBB).These use cases co-exist in many practical scenarios and compete for the same set of time and frequency resources,resulting in a natural trade-off in their performance.In this paper,a network supporting both URLLC and eMBB modes of operation is studied.To guarantee the ultra low latency requirement of URLLC,a dynamic resource allocation scheme indicated by a two-dimensional bitmap is proposed.This approach is capable to achieve finer granularity as well as lower false cancellation rate compared to the state-of-the-art methods.A novel power control and indication method is also proposed to dynamically provide different power control parameters to the user equipment(UE),while guaranteeing the reliability requirement of URLLC and minimizing the impact to eMBB.In addition,we devise a dynamic selection mechanism(DSM)to accommodate diverse scenarios,which is empowered with load prediction to become more intelligent.Our extensive system-level simulation results for eMBB-URLLC co-existence scenarios showcase that the perceived throughput of eMBB UEs is increased by 45.3%,while about 13.3% more UEs are enjoying URLLC services with at most 84% transmit power savings compared to the state-of-the-art methods.
文摘WDM passive optical network becomes more favorable as the required bandwidth increases, but currently few media access control algorithms adapted to WDM acc ess network. This paper presented a new scheduling algorithm for bandwidth shari ng in WDM passive optical networks, which provides per-flow delay guarantee and supports variable-length packets scheduling. Through theoretical analysis and simulation, the end-to-end delay bound and throughput fairness of the algori thm was demonstrated.
文摘提出了一种临界连续模式(CRM)单电感双输出(SIDO)Buck功率因数校正(PFC)变换器及其控制策略,并分析了其工作特性。通过对电感的分时复用控制,实现了2个输出支路的独立控制。在输入电压接近各输出支路电压情况下,控制器限制了开关管的最小关断时间,解决了工作于CRM时电感在输入电流过零点附近难以分时复用控制的问题,并抑制了电感在输入电流过零点附近的复用频率。相对于传统两级结构的多路输出PFC变换器,CRM SIDO Buck PFC变换器减少了控制器与电感的数量,降低了变换器的体积与成本,并提高了变换器的效率。实验结果验证了所提变换器高效率、高功率因数以及2个输出支路的高输出精度控制特性。
