Quantum simultaneous secret distribution with dense coding by using cluster states

A new communication mode, quantum simultaneous secret distribution (QSSD) is put forward, where one sender distributes different classical secret message to multiparty receivers simultaneously. Based on the properties of the one-dimensional four-qubit cluster states, a three-party QSSD protocol is proposed, and then it is extended to the case that there are many receivers. Owing to the idea of quantum dense coding, each receiver can receive two bits of classical message by the sender only using a cluster state. In order to check security of quantum channels, a strategy which can prevent common attacks efficiently is put forward. QSSD is distinct from quantum secret sharing (QSS) and quantum broadcast communication (QBC), but it can be easily converted into QSS and QBC. QSSD is also different from the multiple-QKD communication mode where the sender shares a private key with each receiver at first, while in QSSD the sender doesn’t; in addition, only one round of one-to-many communication is performed in QSSD, while in multiple-QKD communication mode many rounds of one-to-one communication are performed.     

基于网络编码的传染路由协议性能

针对传染路由(ER)网络中容易出现多种通信半径的通信节点,导致网络性能不稳定的问题,提出了一种网络编码与传染路由相结合的网络模型。该模型在经典传染路由中结合网络编码的方式进行数据传输,并且为了对改进后的网络性能进行有效地评估,为传染路由网络中的传输时延建立了概率模型。使用该概率模型对网络进行评估的结果显示,在多种传输环境下与经典传染路由相比,基于网络编码的传染路由(NCER)具有高效、稳定的优点,并于离散事件仿真实验结果中得到了验证。最后,根据该概率模型的评估结果,提出了一种进一步降低网络传输时延的方案。     

Performance analysis of the stop-and-wait automatic repeat request protocol under Markovian interruptions

Frontiers of Information Technology & Electronic Engineering - The performance of an integrated packet voice/data multiplexer using a stop-and-wait (SW) automatic repeat request (ARQ) protocol...     

Optimal probabilistic dense coding schemes

Dense coding with non-maximally entangled states has been investigated in many different scenarios. We revisit this problem for protocols adopting the standard encoding scheme. In this case, the set of possible classical messages cannot be perfectly distinguished due to the non-orthogonality of the quantum states carrying them. So far, the decoding process has been approached in two ways: (i) The message is always inferred, but with an associated (minimum) error; (ii) the message is inferred without error, but only sometimes; in case of failure, nothing else is done. Here, we generalize on these approaches and propose novel optimal probabilistic decoding schemes. The first uses quantum-state separation to increase the distinguishability of the messages with an optimal success probability. This scheme is shown to include (i) and (ii) as special cases and continuously interpolate between them, which enables the decoder to trade-off between the level of confidence desired to identify the received messages and the success probability for doing so. The second scheme, called multistage decoding, applies only for qudits (d-level quantum systems with \(d>2\)) and consists of further attempts in the state identification process in case of failure in the first one. We show that this scheme is advantageous over (ii) as it increases the mutual information between the sender and receiver.     

Performance analysis of a shortest-delay protocol

A generalized shortest-delay access method (SDAM) protocol for local networks is defined and evaluated. This protocol differs from a previously reported SDAM in that it accommodates a branching-bus topology instead of a single-bus network. It is shown that for small bus-delays, SDAM performs very close to that of M/D1- with perfect scheduling. In this paper, the performance evaluation of SDAM is more pragmatic in that the effects of various protocol overheads (e.g., decoding, turnaround time, initializing packets, etc.) are taken into account. An analysis of the tradeoffs between exhaustive and nonexhaustive transmission disciplines is also presented.     

Dynamics of measurement-induced nonlocality under decoherence

Measurement-induced nonlocality (MIN)—captures nonlocal effects of a quantum state due to local von Neumann projective measurements, is a bona-fide measure of quantum correlation between constituents of a composite system. In this paper, we study the dynamical behavior of entanglement (measured by concurrence), Hilbert–Schmidt MIN and fidelity-based MIN (F-MIN) under local noisy channels such as hybrid (consists of bit flip, phase flip and bit-phase flip), generalized amplitude damping (GAD) and depolarizing channels for the initial Bell diagonal state. We observed that while sudden death of entanglement occurs in hybrid and GAD channels, MIN and F-MIN are more robust against such noises. Finally, we demonstrate the revival of MIN and F-MIN after a dark point of time against depolarizing noise.     

基于ZigBee协议的WAPN性能分析

无线个域网是一种近距离、低能耗、无需基础设施的网络,对其性能做定量分析尤为必要.本文对工作在饱和状态、信标使能、星形扑拓情况下的ZigBee网络进行了分析,引入离散马尔可夫链模型对其MAC层的接入概率进行讨论,推导出接入概率和节点数、帧长的关系.并提出了一些应用建议.     

多场景的MPTCP协议性能分析研究

利用多宿主设备的多个接口实现多路径传输、获取更多的网络吞吐量是因特网协议研究的热点。IETF所关注的MPTCP协议是当前比较成熟、关键的多路径传输协议。为了测试MPTCP在当前已部署的网络环境中的性能,分别在本地测试床、Internet环境测试场景和大规模多宿主系统NorNet测试床中对MPTCP多路径传输实际吞吐量性能进行了测试和分析,测试结果表明MPTCP相对TCP虽能获得吞吐量的提高,但在非相似带宽链路的场景中其性能仍然不完善,其路径管理和传输调度策略仍需要进一步改进。     

Multipartite concurrence for X states under decoherence

In this paper, the dynamics evolution of multipartite entanglement for each qubit interacting with a local decoherence channel, such as phase damping, phase flip, bit flip and bit-phase flip channel, is investigated. It is shown that the initial concurrence monotonously decreases much faster with the number of qubit increases and there exists entanglement sudden death (ESD) only for the bit flip channel and bit-phase flip channels. Meanwhile, the time of ESD decreases with the increases of the number of qubit in the multipartite system.     

Perfect quantum multiple-unicast network coding protocol

In order to realize long-distance and large-scale quantum communication, it is natural to utilize quantum repeater. For a general quantum multiple-unicast network, it is still puzzling how to complete communication tasks perfectly with less resources such as registers. In this paper, we solve this problem. By applying quantum repeaters to multiple-unicast communication problem, we give encoding–decoding schemes for source nodes, internal ones and target ones, respectively. Source-target nodes share EPR pairs by using our encoding–decoding schemes over quantum multiple-unicast network. Furthermore, quantum communication can be accomplished perfectly via teleportation. Compared with existed schemes, our schemes can reduce resource consumption and realize long-distance transmission of quantum information.     

Three-player quantum Kolkata restaurant problem under decoherence

Effect of quantum decoherence in a three-player quantum Kolkata restaurant problem is investigated using tripartite entangled qutrit states. Different qutrit channels such as, amplitude damping, depolarizing, phase damping, trit-phase flip and phase flip channels are considered to analyze the behaviour of players payoffs. It is seen that Alice’s payoff is heavily influenced by the amplitude damping channel as compared to the depolarizing and flipping channels. However, for higher level of decoherence, Alice’s payoff is strongly affected by depolarizing noise. Whereas the behaviour of phase damping channel is symmetrical around 50% decoherence. It is also seen that for maximum decoherence (p = 1), the influence of amplitude damping channel dominates over depolarizing and flipping channels. Whereas, phase damping channel has no effect on the Alice’s payoff. Therefore, the problem becomes noiseless at maximum decoherence in case of phase damping channel. Furthermore, the Nash equilibrium of the problem does not change under decoherence.     

Quantum network dense coding via continuous-variable graph states

We present a dense coding network based on continuous-variable graph state along with its corresponding protocol. A scheme to distill bipartite entanglement between two arbitrary modes in a graph state is provided in order to realize the dense coding network. We also analyze the capacity of network dense coding and provide a method to calculate its maximum mutual information. As an application, we analyze the performance of dense coding in a square lattice graph state network. The result showed that the mutual information of the dense coding is not largely affected by the complexity of the network. We conclude that the performance of dense coding network is very optimistic.     

Quantum teleportation and dense coding via topological basis

By means of Temperley–Lieb Algebra and topological basis, we make a new realization of topological basis, and get sixteen complete orthonormal topological basis states which are all maximally entangled for four quasi-particles. Then we present an explicit protocol for teleporting an arbitrary two-qubit state via a topological basis entanglement channel. We also show that four bits of classical information can be encoded into a topological basis state by two-particle unitary operations.     

MANET路由协议及其性能研究

MANET(Mobile Ad Hoe Network)是由一组无线移动主机组成的一个没有任何建立好的基础设施或集中管理设备的临时网络。网络拓扑易变、带宽、能源有限是Ad Hoc移动网络的主要特点。重点介绍了Ad hoc网络的组网关键技术——路由协议,并对现在的具有代表性的协议性能进行了比较,研究了在不同环境下的各自路由协议仿真实验所体现出来的性能差别,对Ad hoc的组网具有指导意义。     

自适应低轨卫星MAC协议性能分析

针对低轨卫星通信信道碰撞检测能力弱,时延较长和大业务量的特点,提出一种具有接入控制机制的自适应APRMA MAC协议。通过对信道负载和业务优先级判断来确定不同业务的接入概率函数,并且接入概率在每个时隙中通过更新来动态适应系统资源的变化。该MAC协议确保多个终端合理共享有限的无线资源同时,系统能达到高容量。通过仿真对语音业务丢包概率、数据包平均时延和数据业务吞吐量三个衡量协议性能指标与传统协议进行分析对比,证明了APRMA MAC协议显著改善系统性能。     

智能交通系统中CMIMO-SM-ARQ协议性能建模分析

为提高智能交通系统(ITS)中无线传感器网络(WSN)的吞吐量和能效性能,提出了一种具备空间调制的协同多输入多输出自动重传请求(CMIMO-SM-ARQ)协议.考虑了双发送节点和双接收节点的四节点WSN,其接收节点可以互为中继辅助发送端传输数据,以降低系统中断概率.建立了具有3L+1个状态的CMIMO-SM-ARQ协议离散时间马尔可夫链(DTMC)模型,并给出状态空间.根据WSN的中断概率和一步状态转移概率矩阵推导CMIMO-SM-ARQ协议的吞吐量、能效和时延性能解析表达式.数值模拟结果表明,所提协议的中断概率和能效性能优于单输入单输出自动重传请求(SISO-ARQ)协议,在中远距离(大于67 m)传输信息时,CMIMO-SM-ARQ具有较高的吞吐量和较低的时延.     

可自扩展的DSR路由协议的性能分析与仿真

针对DSR路由协议路由发现过程速度慢的不足,提出了一种可自扩展的DSR路由协议--IDSR协议,并与传统的DSR协议的性能指标进行了分析和比较.该协议通过限制DSR的路由请求过程中对全网络洪泛的机制,把路由请求的范围限制在了一定的区域内,然后根据实际情况逐层扩大请求范围,使其具有自扩展功能.仿真结果表明该协议的基本性能指标要好于传统DSR协议的.     

基于网络编码的移动传感网传染路由性能分析

建立了基于常微分方程的传染路由协议分析模型,提出了基于网络编码的传染路由协议,并与传统传染路由协议进行比较,引入传输延迟和冗余度两个性能指标评估所提出模型的有效性。理论分析和仿真结果证明传染路由中使用该常微分方程模型分析协议性能是可行的,与传统传染路由协议相比,基于网络编码的传染路由协议可以减少传输延迟,尤其在缓存和带宽受限的情况下,对于减少传输延迟有着明显的优势。     

基于MAODV协议的网络编码方案*

目前网络编码在Ad hoc组播网络中的应用研究比较缺乏,针对这个问题,提出了一种在由MAODV协议(multicast Ad hoc on-demand distance vector routing protocol)组建的Ad hoc组播网络中使用网络编码的网络编码策略,并且为了解决如何解码的问题提出了网络编码处理策略,使得网络编码可以应用在Ad hoc组播网络中,提高了网络性能。理论分析和仿真结果表明,基于网络编码的Ad hoc组播网络与普通Ad hoc组播网络相比,减少了数据包发送次数,降低了网络     

一种基于叠加编码的协作传输协议

针对传统三节点协作通信模型虽简单易行,但其中两阶段协作传输过程中中继节点通常无偿为源节点转发数据,存在频谱效率低的缺点,基于解码转发（decode and forward,DF）协作协议,以提高系统传输速率为目标,利用链路层控制信息的交换获得链路状态信息（channel statue information,CSI）,提出一种基于叠加编码的协作通信机制。协作中,允许中继节点在转发源节点数据的同时,利用叠加编码进行自身数据的发送,通过灵活调整叠加编码时的功率分配,保证系统的传输速率。仿真结果表明,该机制能有效提高系统的传输速率。