A New Approach to Analyse Asynchronous CSMA Wireless Networks Based on Hidden Node Models

We consider a wireless network with a large number of nodes (access points) randomly placed in the plane, employing Carrier Sense Multiple Access (CSMA) protocols to transmit over the same wireless channel in a realistic propagation environment. Focusing on asynchronous rather than synchronous access scheme, several nodes which are mutually hidden from each other may start their transmissions simultaneously. Thus, we model asynchronous CSMA network according to a 3-D Poisson point process which accounts for random distribution of active (transmitting) nodes in time and space. To accurately study the dynamics of the number of active nodes, a novel state-dependant Markovian model is also proposed wherein transition rates are explicitly dependent on the stochastic geometry of the active nodes. This facilitates the procedure to derive a closed form expression for the back-off probability. Finally, the proposed model is validated through simulations and by comparison with previously developed methods.