Throughput Analysis of a p-Persistent CSMA Protocol with QoS Differentiation for Multiple Traffic Types

With the widespread success of 802.11 wireless local area networks (WLANs) and the need for quality of service (QoS) the 802.11e amendment was created. This amendment specifies the enhanced distributed channel access (EDCA) procedure which provides QoS through service differentiation. The underlying mechanism for the contention based access of 802.11 and 802.11e is carrier sense multiple access with collision avoidance (CSMA/CA). p-persistent carrier sense multiple access (p-persistent CSMA) can be used to model CSMA/CA. This paper modifies the p-persistent CSMA mechanism to provide service differentiation in a saturated network. This is a new general model for providing QoS through contention based access. This p-persistent CSMA model is then converted into a model for an 802.11e network. Simulations and comparison with other 802.11e models validates this model while the benefit of this model is that it can be modified readily to characterise service differentiation in a non-saturated network.