Opportunistic routing(OR) is an effective way to guarantee transmission reliability in wireless multi-hop networks.However,little research focuses on transmission efficiency.Thus,an analytical model based on open queu...Opportunistic routing(OR) is an effective way to guarantee transmission reliability in wireless multi-hop networks.However,little research focuses on transmission efficiency.Thus,an analytical model based on open queuing network with Markov chains was proposed to evaluate the efficiency.By analyzing two typical ORs,we find duplicate transmission and collision avoidance overhead are the root reasons behind inefficiency.Therefore,a new scheme called dual priority cooperative opportunistic routing(DPCOR) was proposed.In DPCOR,forwarding candidates are configured with dual priority,which enables the network to classify forwarding candidates more effectively so as to reduce the back-off time and obtain more diversity gain.Theoretical analysis and simulation results show DPCOR achieves significant performance improvement with less time overhead compared with traditional routings and typical ORs.展开更多
This paper investigates the social-aware cooperation(SAC) among mobile terminals(MTs), motivated by the fact that modern smart devices have much improved context awareness. Aware of the social ties, the cooperative ne...This paper investigates the social-aware cooperation(SAC) among mobile terminals(MTs), motivated by the fact that modern smart devices have much improved context awareness. Aware of the social ties, the cooperative network contains two layers of property: social and physical. In order to observe how the social awareness benefit the cooperation performance, we first formulate the social ties between MTs into parameters that can describe the cooperative behaviors by taking the mobility feature into account, defined as the conviction-approval-suspicion(CAS) model. Limited by the processing capability, partner selection is of great practical significance. To this end, the social-aware partner selection strategy is analyzed, and a significant superiority is observed compared to social-unaware selection. By analyzing the cooperative throughput, an explicit relationship between the degrees-of-freedom gain and the social-physical property is finally derived. Simulation results validate the theoretical analysis.展开更多
An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and impr...An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and improve the system performance.In optical line terminal(OLT),OQAM-OFDM signals at 40 Gbit/s are transmitted as downstream.At each optical network unit(ONU),the optical OQAM-OFDM signal is demodulated with direct detection.The results show that the transmission distance can exceed 20 km with negligible penalty under the experimental conditions.展开更多
基金supported by the National Science and Technology Major Projects under Grant No.2011ZX03001-007-03
文摘Opportunistic routing(OR) is an effective way to guarantee transmission reliability in wireless multi-hop networks.However,little research focuses on transmission efficiency.Thus,an analytical model based on open queuing network with Markov chains was proposed to evaluate the efficiency.By analyzing two typical ORs,we find duplicate transmission and collision avoidance overhead are the root reasons behind inefficiency.Therefore,a new scheme called dual priority cooperative opportunistic routing(DPCOR) was proposed.In DPCOR,forwarding candidates are configured with dual priority,which enables the network to classify forwarding candidates more effectively so as to reduce the back-off time and obtain more diversity gain.Theoretical analysis and simulation results show DPCOR achieves significant performance improvement with less time overhead compared with traditional routings and typical ORs.
基金supported by the National Basic Research Program of China (2013CB329001)the National Natural Science Foundation of China (61132002, 61201186)
文摘This paper investigates the social-aware cooperation(SAC) among mobile terminals(MTs), motivated by the fact that modern smart devices have much improved context awareness. Aware of the social ties, the cooperative network contains two layers of property: social and physical. In order to observe how the social awareness benefit the cooperation performance, we first formulate the social ties between MTs into parameters that can describe the cooperative behaviors by taking the mobility feature into account, defined as the conviction-approval-suspicion(CAS) model. Limited by the processing capability, partner selection is of great practical significance. To this end, the social-aware partner selection strategy is analyzed, and a significant superiority is observed compared to social-unaware selection. By analyzing the cooperative throughput, an explicit relationship between the degrees-of-freedom gain and the social-physical property is finally derived. Simulation results validate the theoretical analysis.
基金supported by the National Natural Science Foundation of China(No.61431009)the Natural Science Foundation of Shandong Province(No.ZR2014FL002)
文摘An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and improve the system performance.In optical line terminal(OLT),OQAM-OFDM signals at 40 Gbit/s are transmitted as downstream.At each optical network unit(ONU),the optical OQAM-OFDM signal is demodulated with direct detection.The results show that the transmission distance can exceed 20 km with negligible penalty under the experimental conditions.
