CAJ | 학술논문

　　为了提高苗圃灌溉控制系统的稳定性和健壮性，该文在无线传感器网络中，以网关节点调度为目标，提出了一种新的基于马尔可夫链的网关节点调度方法。首先，理论上分析单个网络节点的存在状态，及其接入行为；其次，以网关和终端节点共同状态为基础，通过单个节点的状态转移概率关系，得到系统平衡方程；第三，根据此平衡方程进行节点的调度，以及描述系统工作过程；最后对得出的系统调度模型进行性能参数估计。试验建立一个无线传感器网络仿真平台，对该模型进行从带宽利用率、被迫中断概率、以及网络容量和阻塞率进行比较分析。结果表明随着用户的呼叫率增多，带宽的利用率、终端被迫中断概率和系统容量都随之增长，而当呼叫量增长到一定程度时，系统容量会慢慢趋于平缓。该模型在提高传感器网络带宽利用率的同时保证了一定的系统中断概率。
　　위료제고묘포관개공제계통적은정성화건장성，해문재무선전감기망락중，이망관절점조도위목표，제출료일충신적기우마이가부련적망관절점조도방법。수선，이론상분석단개망락절점적존재상태，급기접입행위；기차，이망관화종단절점공동상태위기출，통과단개절점적상태전이개솔관계，득도계통평형방정；제삼，근거차평형방정진행절점적조도，이급묘술계통공작과정；최후대득출적계통조도모형진행성능삼수고계。시험건립일개무선전감기망락방진평태，대해모형진행종대관이용솔、피박중단개솔、이급망락용량화조새솔진행비교분석。결과표명수착용호적호규솔증다，대관적이용솔、종단피박중단개솔화계통용량도수지증장，이당호규량증장도일정정도시，계통용량회만만추우평완。해모형재제고전감기망락대관이용솔적동시보증료일정적계통중단개솔。
In order to schedule a gateway node in wireless sensor networks, this paper proposes a new gateway node scheduling method which based on a Markov chain. The research method of this paper is: first, theory analyses one single network node’s existential state, and its access behavior;second, we base on the gateway and terminal node’s common status, via single node’s state transition probability relation to build up system’s balance equation;third, according to this balance equation, anode’s scheduling is executed, as well as a description of the system working process;finally, the system’s performance parameters of the scheduling method is estimated. This paper’s experiment built a wireless sensor network simulated model, set up the simulation environment, constructed several gateway nodes, terminal nodes, wireless channel bandwidth, node’s transmitting power, channel’s signal-to-noise ratio, Rayleigh flat fading channel, etc. system parameters. Simulation analysis was conducted on this network model’s bandwidth utilization and forced interrupt probability;then changing a node’s signal-to-noise ratio’s value, the simulation compared network capacity and blocking probability performance. Research result:first, with the increasing of a user’s call rate, the bandwidth utilization also grows, because the call’s increasing inevitable causes a system’s collaboration gateway node to increase. When the system reaches a steady state, the bandwidth utilization is maintained at 10% to 70%. Second, the forced interrupt probability is also increased with a user’s increasing call rate, on the one hand, call’s increase leads a gateway node’s state transition frequency to increase, on the other hand, the system tendency to a steady-state probability is also increased, thus interrupt probability increases, but the experimental results derived interrupt probability value is always less than 0.1, and this can content general quality of service (QoS) performance requirements. Third, system capacity is increased with call volumes increasing. With call increasing, the system spectrum utilization is correspondingly increased, and this will inevitably lead to the growth of system capacity. Meanwhile, when the call volume grows to a certain extent, the system capacity will gradually flatten, which is due to the system interrupt probability that will also flatten with call’s increasing. The system will eventually reach a state of equilibrium finally. In order to enhance a node’s efficiency in a relay system, it is necessary to do a reasonable arrangement for the access node itself working condition and between each node. According to a node’s own state transition situation and interaction between each node in relay system, a relay system node scheduling model based on a discrete time Markov chain model is constructed. System equilibrium state is analyzed. The results show that, based on a relay node’s rational utilization, we improve system bandwidth utilization, while keeping a lower system interrupt probability. It can improve the stability and robustness of farmland nursery irrigation sensor networks.