Modeling Of Access Performance Evaluation And Optimization Research On Wireless Communication Networks

Along with the popularization of personal communication and the development of the wireless communacation technology, the categories of traffic in the wireless communication network (WCN) are becoming more and more abundant, whose quantity also increases rapidly. The finite property of bandwidth of the WCN makes the access performance analysis of importance. The problem of channal access is how the competitive customers share the network resource. Hence the effective channel access models and performance analysis methods are the premise to improve the network performance in the WCN. Based on the accurate modeling methods in the queueing theory, many kinds of access models in the WCN are established and the expressions of network performance measures are also obtained through analyzing the models in this paper. Furthermore, the optimal results of the system parameters are presented by the method of simulation analysis, which provide important theoretical basis and analysis methods for the optimal design and reasonable collocation of the WCN.Firstly, according to the characteristic of the digital mobile communication network, the discrete-time Geom/Geom/c/c queue and the Geom/Geom/c/c/N queue with finite users and infinite buffers as well as the Geom/Geom/c/K/N queue with finite buffers are established. Based on the three models, the access process of the WCN is modeled and expressions of the important performance measures are derived. The relationships between the system performance measures and the system loads are compared in different models.Secondly, aiming at the multi-traffic access property of the WCN, the double traffic M1,M2/M1,M2/c/c,∞queue model with mixed loss is established. Moreover, two discrete-time queue models with preemptive access policy of the delayed sensitive traffic and with infinite and finite buffers are established, respectively. And multi-access performance measures, such as blocking probability, mean waiting time and expected using ratio of the channels, for each thaffic are derived by the method of matrix geomitric solution. The optimal results of the system parameters under various QoS constraintconditions are also obtained.Thirdly, considering the energy management of the mobile nodes in the mobile Ad hoc networks, the models concerned about the access performance of the WCN are established through introducing vacation queue models with partial-server vacation policies. In this paper, two queue models are proposed to model the multi-access process of the nodes, one is the queue with asynchronous N-policy vacations, the other is the queue with synchronous (e, d)-policy vacations. Sleeping indices of the system, such as the sleeping threshold and awaken threshold, are set. The effects of the sleeping indices and the syschronous and asynchronous policies on the system performance are compared with each other, and the optimal results of these sleeping indices are obtained by numerical simulation.Finally, considering the mobile property of users in the WCN, the spatial queues with SPHAP (Spatial Phase Arrival Process) are introduced to describe the spatial structure of the arrival process from differet service regions of a cell, and a SPHAP/M/c/c queue is established to model the multi-access from different regions. The spatial performance measures, which are used to design and analyze the spatial structure of the WCN, are derived. Then an optimal strategy is designed, and the optimal results are also obtained by the system simulation.