Communication load and delay in multichannel land mobile systems for dispatch traffic: A queueing analysis

Methods for analysis of land mobile radio trunked systems with dispatch traffic were investigated. A queuing model is proposed to take into account fleet delays, which occur when mobile operators must wait because their own dispatchers are busy with a call. A decomposition approach is applied to solve the model using well-known queuing results. Once the distribution of central delays due to channel sharing is known, fleet delays are computed by means of an M/G/1 model with finite population. For trunked systems supporting a large number of fleets, the analysis of central delays is performed using the G/H₂/s queue. When the number of fleets is not much greater than the number of channels, channel sharing delays must be analyzed by means of a multiserver queue with finite population. Simulations are used to validate the decomposition approach. The results obtained show that besides depending on the communication load, the grade of service of trunked systems also depends on the size of fleets