Effects of Carrier Sense Modeling on Wireless Network Simulation Results

摘要

We investigate the effect of radio modeling on the simulation results of low-power wireless networks. In particular we focus on the modeling of carrier sensing and state transition delays and describe how these aspects of low-power radios are captured in the Castalia simulator. These aspects are usually neglected by network-level simulators yet they can have a significant effect on the higher level simulation results. We show these effects by exploring a simple simulation scenario: a clique of N nodes -all in range with each other- with N-l transmitter nodes sending packets to one receiver node, employing the simple CSMA/CA MAC protocol. Varying the sending rate and number of nodes, we show that the throughput at the receiver node can greatly vary depending on the assumptions we make about the radio. We also show that simple decisions at the MAC level, such as the back-off duration and the method of transmitting buffered packets, have a much more pronounced effect on performance when the radio is modeled more accurately.