A novel routing architecture named DREAMSCAPE is presented to solve the problem of path computation in multi-layer, multi-domain and multi-constraints scenarios, which includes Group Engine (GE) and Unit Engine (UE). ...A novel routing architecture named DREAMSCAPE is presented to solve the problem of path computation in multi-layer, multi-domain and multi-constraints scenarios, which includes Group Engine (GE) and Unit Engine (UE). GE, UE and their cooperation relationship form the main feature of DREAMSCAPE, i.e. Dual Routing Engine (DRE). Based on DRE, two routing schemes are proposed, which are DRE Forward Path Computation (DRE-FPC) and Hierarchical DRE Backward Recursive PCE-based Computation (HDRE-BRPC). In order to validate various intelligent networking technologies of large-scale heterogeneous optical networks, a DRE-based transport optical networks testbed is built with 1000 GMPLS-based control nodes and 5 optical transport nodes. The two proposed routing schemes, i.e. DRE-FPC and HDRE-BRPC, are validated on the testbed, compared with traditional Hierarchical Routing (HR) scheme. Experimental results show a good performance of DREAMSCAPE.展开更多
Bandwidth-variable optical networks can not only provide bandwidth-flexible lightpaths, but also complete high capacity all-optical switching, and improve the spectrum efficiency. However, for the spectrum assignment ...Bandwidth-variable optical networks can not only provide bandwidth-flexible lightpaths, but also complete high capacity all-optical switching, and improve the spectrum efficiency. However, for the spectrum assignment in orthogonal frequency-division multiplexing （OFDM）-based bandwidth-variable optical networks, a lot of sub-carrier resources will be overlapped during the process of reservation with distributed signaling, whether for the first fit （FF） algorithm or for the random fit （RF） algorithm, In order to solve the issue of resource reservation collision, we propose two path computation element （PCE）-based spectrum assignment algorithms and two corresponding optimization algorithms. But, even for PCE-based spectrum assignment, a lot of fragments of sub-carrier resources will be generated during the process of resource reservation, and service LSP establishment and teardown, which will deteriorate the performance of the entire network seriously. This paper proposes a PCE-based defragmentation algorithm for sub-carriers spectrum resource in OFDM-based bandwidth-variable optical networks, the simulation results of which show that this algorithm can reduce sub-carriers fragments considerably and improve the continuity of spectrum resource.展开更多
In this article, multiple receiver effects in a non-line-of-sight （NLOS） ultraviolet （UV） communication system is studied. The idea of using multiple receivers for diversity reception is known as a practical, effe...In this article, multiple receiver effects in a non-line-of-sight （NLOS） ultraviolet （UV） communication system is studied. The idea of using multiple receivers for diversity reception is known as a practical, effective and widely applied technique in wireless communications. The current approach is to use multiple antennas at the receiver in order to improve the quality of the received signal. A method of modeling and simulation is proposed to depict the principle and feasibility of the multiple receiver adopted in UV communication. The study provides an insight to the channel characteristics and achievable capabilities of ultraviolet communication systems with multiple receivers. It provides guidelines for practical system design with discussions on trade off between the receiver gain and the additional cost.展开更多
基金supported in part by National Key Basic Research Program of China (973 program) under Grant No.2010CB328204National High Technology Research and Development Program of China (863 program) under Grant No.2009AA01Z255+3 种基金National Natural Science Foundation of China under Grant No. 60932004RFDP Project under Grant No.20090005110013111 Project of China under Grant No.B07005China Fundamental Research Funds for the Central Universities
文摘A novel routing architecture named DREAMSCAPE is presented to solve the problem of path computation in multi-layer, multi-domain and multi-constraints scenarios, which includes Group Engine (GE) and Unit Engine (UE). GE, UE and their cooperation relationship form the main feature of DREAMSCAPE, i.e. Dual Routing Engine (DRE). Based on DRE, two routing schemes are proposed, which are DRE Forward Path Computation (DRE-FPC) and Hierarchical DRE Backward Recursive PCE-based Computation (HDRE-BRPC). In order to validate various intelligent networking technologies of large-scale heterogeneous optical networks, a DRE-based transport optical networks testbed is built with 1000 GMPLS-based control nodes and 5 optical transport nodes. The two proposed routing schemes, i.e. DRE-FPC and HDRE-BRPC, are validated on the testbed, compared with traditional Hierarchical Routing (HR) scheme. Experimental results show a good performance of DREAMSCAPE.
基金supported by the National Basic Research Program of China (2010CB328204)the National Natural Science Foundation of China (60932004)+3 种基金the Hi-Tech Research and Development Program of China (2012AA011301)the RFDP Project (20090005110013)The 111 Project (B07005)the Fundamental Research Funds for the Central Universities
文摘Bandwidth-variable optical networks can not only provide bandwidth-flexible lightpaths, but also complete high capacity all-optical switching, and improve the spectrum efficiency. However, for the spectrum assignment in orthogonal frequency-division multiplexing （OFDM）-based bandwidth-variable optical networks, a lot of sub-carrier resources will be overlapped during the process of reservation with distributed signaling, whether for the first fit （FF） algorithm or for the random fit （RF） algorithm, In order to solve the issue of resource reservation collision, we propose two path computation element （PCE）-based spectrum assignment algorithms and two corresponding optimization algorithms. But, even for PCE-based spectrum assignment, a lot of fragments of sub-carrier resources will be generated during the process of resource reservation, and service LSP establishment and teardown, which will deteriorate the performance of the entire network seriously. This paper proposes a PCE-based defragmentation algorithm for sub-carriers spectrum resource in OFDM-based bandwidth-variable optical networks, the simulation results of which show that this algorithm can reduce sub-carriers fragments considerably and improve the continuity of spectrum resource.
文摘In this article, multiple receiver effects in a non-line-of-sight （NLOS） ultraviolet （UV） communication system is studied. The idea of using multiple receivers for diversity reception is known as a practical, effective and widely applied technique in wireless communications. The current approach is to use multiple antennas at the receiver in order to improve the quality of the received signal. A method of modeling and simulation is proposed to depict the principle and feasibility of the multiple receiver adopted in UV communication. The study provides an insight to the channel characteristics and achievable capabilities of ultraviolet communication systems with multiple receivers. It provides guidelines for practical system design with discussions on trade off between the receiver gain and the additional cost.
