Performance modeling of a two-tier primary-secondary network with IEEE 802.11 broadcast scheme

In this paper, we study the performance of a two-tier primary-secondary network based on IEEE 802.11 broadcast scheme. We assume that a number of primary and secondary users coexist in the radio environment and share a single band. To protect the primary users´ priority, the secondary users are allowed to contend for the channel only if they sense it idle for a certain sensing time. Considering an exponential packet inter-arrival time for the primary network, we model each primary user as an independent M/G/1 queue. Subsequently, we determine the primary users´ average medium access delay in the presence of secondary users as well as the hybrid network´s throughput. Numerical results and discussions show the effects of parameters pertaining to the secondary users, such as as sensing time, packet payload size and population size, on the performance of the primary network. Furthermore, we provide simulation results which confirm the accuracy of the proposed analysis.