Optimal Channel Access through Implicit Resource Reservation in Csma Networks

Carrier Sense Multiple Access (CSMA) networks are basically wireless LANs. The CSMA is a method that uses carrier sensing scheme in which the station which transmits data can detect collision and takes appropriate steps to have collision-free communication. Many stations in these networks share common resources for successful transmission of data. Resource reservation is one of the well known techniques that enable reserving shared resources to stations in order to improve communication efficiency and reduce contention. Especially the time-slot reservation in CSMA networks is a challenging and open problem to be addressed. Recently He et al. proposed a semirandom back off (SRB) method for contention based wireless networks that facilitate resource reservation. The SRB is different from random back off approach where it employs deterministic slot assignments in CSMA networks. The notion of back off counter is used which is set to zero on successful transmission of packets. As time slots are reused effectively on successive back off cycles continuously the implicit resource reservation is achieved besides reducing collision probability. In this paper we implemented this methodology using NS2. The simulation results reveal that the approach is useful in optimal utilization of resources.