Resilient Packet Ring (RPR) is a Media Access Control (MAC) layer protocol that operates over a double counter-rotating ring network topology. RPR is designed to enhance Synchronous Digital Hierarchy(SDH) in order to ...Resilient Packet Ring (RPR) is a Media Access Control (MAC) layer protocol that operates over a double counter-rotating ring network topology. RPR is designed to enhance Synchronous Digital Hierarchy(SDH) in order to handle data traffic more efficiently. Since Intelligent Protection Switching(IPS) is one of the key technologies in ring networks, RPR provides two intelligent protection algorithms: steering and wrapping. While wrapping in RPR in essence inherits the automatic protection switching(APS) algorithm of SDH, it also wastes the bandwidth on the wrapping ringlets and may result in severe congestion. Whereas steering in RPR provides high bandwidth utilization, its switching speed is low, because it is indeed a high layer's restoration algorithm. In this paper, integrated self-healing(ISH) algorithm as an effective algorithm for RPR is proposed, which synthesizes the merits of the two algorithms by transporting healing signal and computing routing in MAC layer. At last, the performance of ISH algorithm is analyzed and simulated.展开更多
In this paper , we have established an intimate connection between near-nings and linear automata,and obtain the following results: 1) For a near-ring N there exists a linear GSA S with N ≌ N(S) iff (a) (N, +) is abe...In this paper , we have established an intimate connection between near-nings and linear automata,and obtain the following results: 1) For a near-ring N there exists a linear GSA S with N ≌ N(S) iff (a) (N, +) is abelian, (b) N has an identity 1, (c) There is some d ∈ Nd such that N0 is generated by {1,d};2) Let h: S → S’ be a GSA- epimorphism. Then there exists a near-ring epimorphism from N(S) to N(S’) with h(qn) = h(q)h(n) for all q ∈ Q and n ∈ N(S);3) Let A = (Q,A,B,F,G) be a GA. Then (a) Aa:=(Q(N(A)) =: Qa,A,B,F/Qa × A) is accessible, (b) Q = 0N(A), (c) A/~:= (Q/~,A,B,F~), Q~) with F^([q], a):= [F(q,a)] and G^([q], a):= G(q,a) is reduced, (d) Aa/~ is minimal.展开更多
在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对...在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对定向航空中继网络中由于通信链路长、无线信号传播时延与数据传输时延相近,所引起的通信时延扩展、多址接入协议效率低等问题,提出了一种基于通信链路距离进行分环的时分多址接入协议(link distance division based time division multiple access protocol,LDD-TDMA)。与传统的TDMA多址接入协议中所有链路均使用相同的时隙长度不同,LDD-TDMA根据通信链路的距离远近使用不同的时隙长度。进一步为了简化协议实现,提出通信覆盖范围分环的概念,使得处于同一个环内链路距离相近的节点使用相同的时隙长度。接着,建模分析并推导出了最大化多址接入效率的分环的个数、分环半径与节点最大通信距离之间的闭合表达式。最后,仿真结果表明,当中继飞机最大通信距离为200 km、分环个数为4时,LDD-TDMA的多址接入效率相较于传统的TDMA可提高13.37%。展开更多
文摘Resilient Packet Ring (RPR) is a Media Access Control (MAC) layer protocol that operates over a double counter-rotating ring network topology. RPR is designed to enhance Synchronous Digital Hierarchy(SDH) in order to handle data traffic more efficiently. Since Intelligent Protection Switching(IPS) is one of the key technologies in ring networks, RPR provides two intelligent protection algorithms: steering and wrapping. While wrapping in RPR in essence inherits the automatic protection switching(APS) algorithm of SDH, it also wastes the bandwidth on the wrapping ringlets and may result in severe congestion. Whereas steering in RPR provides high bandwidth utilization, its switching speed is low, because it is indeed a high layer's restoration algorithm. In this paper, integrated self-healing(ISH) algorithm as an effective algorithm for RPR is proposed, which synthesizes the merits of the two algorithms by transporting healing signal and computing routing in MAC layer. At last, the performance of ISH algorithm is analyzed and simulated.
文摘In this paper , we have established an intimate connection between near-nings and linear automata,and obtain the following results: 1) For a near-ring N there exists a linear GSA S with N ≌ N(S) iff (a) (N, +) is abelian, (b) N has an identity 1, (c) There is some d ∈ Nd such that N0 is generated by {1,d};2) Let h: S → S’ be a GSA- epimorphism. Then there exists a near-ring epimorphism from N(S) to N(S’) with h(qn) = h(q)h(n) for all q ∈ Q and n ∈ N(S);3) Let A = (Q,A,B,F,G) be a GA. Then (a) Aa:=(Q(N(A)) =: Qa,A,B,F/Qa × A) is accessible, (b) Q = 0N(A), (c) A/~:= (Q/~,A,B,F~), Q~) with F^([q], a):= [F(q,a)] and G^([q], a):= G(q,a) is reduced, (d) Aa/~ is minimal.
文摘在定向航空中继网络中,中继飞机利用定向天线通信距离远、发射功率小、无线信号干扰范围小等优点,辅助地面节点克服地形遮挡、信号衰弱大、通信距离受限等缺点,以较少的跳数进行通信,有效降低端到端数据传输时延、提高网络吞吐量。针对定向航空中继网络中由于通信链路长、无线信号传播时延与数据传输时延相近,所引起的通信时延扩展、多址接入协议效率低等问题,提出了一种基于通信链路距离进行分环的时分多址接入协议(link distance division based time division multiple access protocol,LDD-TDMA)。与传统的TDMA多址接入协议中所有链路均使用相同的时隙长度不同,LDD-TDMA根据通信链路的距离远近使用不同的时隙长度。进一步为了简化协议实现,提出通信覆盖范围分环的概念,使得处于同一个环内链路距离相近的节点使用相同的时隙长度。接着,建模分析并推导出了最大化多址接入效率的分环的个数、分环半径与节点最大通信距离之间的闭合表达式。最后,仿真结果表明,当中继飞机最大通信距离为200 km、分环个数为4时,LDD-TDMA的多址接入效率相较于传统的TDMA可提高13.37%。
