Research on Channel Access Protocol and Routing Technology in Wireless Ad hoc Networks

无线自组网络是一种特殊的无线通信网络，具有快速、独立组网的特点，它 不需要固定通信设备的支持，能够随着节点的加入、离开，以及节点的移动进行 自组织、自管理。这些优势使得无线自组网具有相当广阔的应用前景。 无线自组网的信道接入（MediaAccessControl，MAC）协议控制节点如何 获取无线信道，对无线自组网络的性能具有决定性的影响，但是由于无线自组网 的分布式和多跳性，使得信道接入协议的设计具有很大的挑战性；另外其路由技 术决定数据分组是否能够按时可靠的传输，快速有效的路由选择能够降低路由控 制开销、提高网络吞吐量，但是由于无线自组网拓扑动态变化，使得对无线自组 网的路...Wireless ad hoc networks is a special wireless network, with features of rapidly and independently deploying, it does not require the support of the fixed communications equipment, and it can self-organizing and self-management with the addition, left, and mobility of nodes. These advantages make the wireless ad hoc networks have very broad application prospects. In the wireless ad hoc networ...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332009115281

Performance Analysis Model for IEEE 802.11 Distributed Coordination Function Protocol

提出了一种改进的二维MArkOV链模型用于分析IEEE 802.11 dCf协议.该模型不仅考虑实际应用中饱和业务量和非饱和业务量的情况,而且考虑dCf协议的退避计时器的冻结状态和有限的重传次数.通过对该MArkOV链模型稳定状态的求解并结合M/M/1/k排队模型,导出了dCf系统性能的理论模型.仿真结果表明,该理论模型能够精确地预测广义IEEE 802.11 dCf协议的系统性能.This paper proposes an improved two-dimensional Markov chain model for the performance analysis of the IEEE 802.11 DCF protocol.The model is applicable to both saturated and unsaturated traffic conditions.Moreover,it extends the existing models to take into account previously-ignored MAC layer factors such as backoff freezing and limited times of retry.In addition,by deriving the stationary state of the Markov model and considering an M/M/l/K queuing model,we further derive a theoretical model for evaluating performance of the general IEEE 802.11 DCF protocols.Accuracy of the proposed theoretical model is validated with simulation results.福建省科技重大专项基金(No.2007HZ0003); 福建省自然科学基金(No.2010J01347)资

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies