This paper analyzes the Parallel Packet Switch(PPS) architecture and studies how to guarantee its performance. Firstly a model of Stable PPS (SPPS) is proposed. The constraints of traffic scheduling algorithms, the nu...This paper analyzes the Parallel Packet Switch(PPS) architecture and studies how to guarantee its performance. Firstly a model of Stable PPS (SPPS) is proposed. The constraints of traffic scheduling algorithms, the number of switching layers and internal speedup, for both bufferless and buffered SPPS architecture, are theoretically analyzed. Based on these results, an example of designing a scalable SPPS with 1.28T capacity is presented, and practical considerations on implementing the scheduling algorithm are discussed. Simulations are carried out to investigate the validity and delay performance of the SPPS architecture.展开更多
Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind ...Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying(MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor(KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16 PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.展开更多
文摘This paper analyzes the Parallel Packet Switch(PPS) architecture and studies how to guarantee its performance. Firstly a model of Stable PPS (SPPS) is proposed. The constraints of traffic scheduling algorithms, the number of switching layers and internal speedup, for both bufferless and buffered SPPS architecture, are theoretically analyzed. Based on these results, an example of designing a scalable SPPS with 1.28T capacity is presented, and practical considerations on implementing the scheduling algorithm are discussed. Simulations are carried out to investigate the validity and delay performance of the SPPS architecture.
基金supported by the National Natural Science Foundation of China(No.61671375)the Industrial Research of Science and Technology Plan of Shaanxi Province(No.2016GY-082)
文摘Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying(MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor(KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16 PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.
