In IEEE 802.11 based ad hoc networks, one reason not to receive a packet is due to collisions caused by the well known hidden terminal problem (stressed in the addressed scenario where RTS/CTS mechanism is not applicable). It is also well known that wireless communication protocols may achieve different performance results when assuming different radio propagation models and implementations. While the effect of the hidden terminal problem is well understood when utilizing a deterministic radio propagation model, it has a new ‘flavor’ with the utilization of more realistic ones, which do not experience a fixed Carrier Sense range (CS).
Our contribution in this document is a formalization of a metric able to characterize the effect of different propagation models on IEEE 802.11 networks, and its evaluation (using the ns-2.28 simulator) with respect to packet reception rates. The new metric, which we name Packet Level Incoordination (PLI), is based on the CSMA/CA principle and measures the inability of CSMA/CA of correctly coordinate the nodes on a network from a specific node’s perspective.