Research On Communication Network QoS Based On Queueing Theory

The QoS(quality of service) of communication network will be all-important to the research,application and development of the future network's technique.From the angle of queue theory,this paper tries to study the QoS of communication network, and build the corresponding queue models.By analyzing the models,we obtain the pivotal QoS performance measures as the form of analysis formulas.Firstly,the queue of AF stream at the network node under the DiffServ link is studied.The bandwidth change's rule of the AF stream is simulated by using Markov random environment.The WRED which is used for AF stream's buffer management mechanism at the network node is analyzed.And then the MMPP+MMPP/MMPP/1/K queue model with WRED buffer management mechanism is proposed,also the correlative QoS performance parameters are derived by the solution of the model.Secondly,the D-MAP/PH/1 queue model base on discrete time is built for dynamic priority queue in communication network.By using the method of matrix analysis,the steady-state distribution of the queue is analysed,and the main QoS performance measures are obtained such as average queue length,blocking probability and average delay time of the two traffic.Finally,the buffer-limited D-BMAP/PH/1 multiple vacation queuing model with idle-setup and priority mechanisms is built based on the wireless self-organized network nodes under power management mechanisms.The steady-state distribution of the queuing model is obtained and the main QoS performance measures are derived. Also the idle and sleep periods' influence on the performance of networks under different loads is analyzed by using numerical illustration.The arrival processes which are generalized to Poisson process are adopted in the three models above mentioned.Therefore the models can satisfy the actual condition and the QoS performance measures of communication network can be studied better.