分布式仿真中难于实现统一的全局物理时钟,且节点之间的传输存在抖动,因此为了保证各仿真节点的事件一致性,需要进行仿真时间同步.论文对大规模分布节点的时间同步算法开展研究,对HLA标准中定义的LBTS算法进行性质分析,给出分组管理的L...分布式仿真中难于实现统一的全局物理时钟,且节点之间的传输存在抖动,因此为了保证各仿真节点的事件一致性,需要进行仿真时间同步.论文对大规模分布节点的时间同步算法开展研究,对HLA标准中定义的LBTS算法进行性质分析,给出分组管理的LBTS计算模型.针对现有时间同步算法将可靠控制报文作为默认前提的问题,给出了时间控制报文可靠性定理,证明了只有制约系统推进的一部分报文需要可靠,该默认前提并非必要.在此基础上,设计了MCTS(multi-node coordination time synchronization)算法,根据时间控制报文可靠性定理引入IP组播来处理控制报文的传输,提高了节点的处理效率,大大降低了控制报文的带宽开销.实验结果表明,该算法在节点时间推进速度及网络带宽占用量方面优于同类算法,1000个节点的时间同步推进速度可达到50次/s,相当于同类系统中100个节点时的推进速度.展开更多
Coordinated multi-point （CoMP） transmission is put forward in the long term evolution-advanced （LTE-A） system to improve both average and cell-edge throughput. CoMP-joint pro- cessing （JP） scheme can get a large...Coordinated multi-point （CoMP） transmission is put forward in the long term evolution-advanced （LTE-A） system to improve both average and cell-edge throughput. CoMP-joint pro- cessing （JP） scheme can get a larger cell-edge throughput and a lower bit error rate （BER） than the CoMP-coordinated beamform- ing （CB） scheme, but it also has higher complexity due to data sharing. A hybrid coordinated strategy with parameter c~, which indicates the proportion of users employing the CoMP-JP scheme, is proposed to apply the CoMP-JP scheme to improve the poorer communication quality of cell edge and employ the CoMP-CB scheme for other users to enhance average throughput and spec- tral efficiency. This paradigm selects users defined by the certain threshold of signal to interference plus noise power ratio （SINR） corresponding to the parameter a to the CoMP-JP scheme. This paper compares the BER performance between the block diag- onalization （BD） based precoding and the linear precoders by maximizing signal to leakage and noise ratio （SLNR）, and also in- dicates that the SLNR based precoding algorithm gets lower BER than the BD based precoding algorithm with certain signal-to-noise ratios （SNRs）. Finally, this paper discusses that the system perfor- mance is partially affected by the percentage of CoMP-JP users and concludes that 50% of users sorted to communicate under the CoMP-JP scheme will reach the best system performance.展开更多
文摘分布式仿真中难于实现统一的全局物理时钟,且节点之间的传输存在抖动,因此为了保证各仿真节点的事件一致性,需要进行仿真时间同步.论文对大规模分布节点的时间同步算法开展研究,对HLA标准中定义的LBTS算法进行性质分析,给出分组管理的LBTS计算模型.针对现有时间同步算法将可靠控制报文作为默认前提的问题,给出了时间控制报文可靠性定理,证明了只有制约系统推进的一部分报文需要可靠,该默认前提并非必要.在此基础上,设计了MCTS(multi-node coordination time synchronization)算法,根据时间控制报文可靠性定理引入IP组播来处理控制报文的传输,提高了节点的处理效率,大大降低了控制报文的带宽开销.实验结果表明,该算法在节点时间推进速度及网络带宽占用量方面优于同类算法,1000个节点的时间同步推进速度可达到50次/s,相当于同类系统中100个节点时的推进速度.
基金supported by the National Science and Technology Major Project of China(2013ZX03001024-003)
文摘Coordinated multi-point （CoMP） transmission is put forward in the long term evolution-advanced （LTE-A） system to improve both average and cell-edge throughput. CoMP-joint pro- cessing （JP） scheme can get a larger cell-edge throughput and a lower bit error rate （BER） than the CoMP-coordinated beamform- ing （CB） scheme, but it also has higher complexity due to data sharing. A hybrid coordinated strategy with parameter c~, which indicates the proportion of users employing the CoMP-JP scheme, is proposed to apply the CoMP-JP scheme to improve the poorer communication quality of cell edge and employ the CoMP-CB scheme for other users to enhance average throughput and spec- tral efficiency. This paradigm selects users defined by the certain threshold of signal to interference plus noise power ratio （SINR） corresponding to the parameter a to the CoMP-JP scheme. This paper compares the BER performance between the block diag- onalization （BD） based precoding and the linear precoders by maximizing signal to leakage and noise ratio （SLNR）, and also in- dicates that the SLNR based precoding algorithm gets lower BER than the BD based precoding algorithm with certain signal-to-noise ratios （SNRs）. Finally, this paper discusses that the system perfor- mance is partially affected by the percentage of CoMP-JP users and concludes that 50% of users sorted to communicate under the CoMP-JP scheme will reach the best system performance.
