  The Decentralized Congestion Control (DCC) algorithms specified in ETSI ITS
standards [1] address the IEEE 802.11p MAC and provide reliability of periodic
broadcast messages at high density of vehicles. However, the deterministic
relation between controllable parameters, e.g. transmit power, frame duration,
frame transmit rate and channel clear assessment threshold, and the effects of
DCC algorithms, e.g. channel busy duration, frame interference-free reception
probability and frame channel access delay, is still unknown since a correct
mathematical analysis of the hidden station problem in CSMA networks is
lacking. In this work, the hidden station problem in a linear IEEE 802.11p
broadcast network is analyzed based on analytical results developed in [18]
employing a modified MAC protocol model based on [3]. Simulation results
validate the new analytical model for linear IEEE 802.11p networks w.r.t
reliability and latency performances of Cooperative Awareness Message
broadcast. Evidence is given that the model not only is valid for single-lane
highways but also provides good approximate results for multi-lane highway
scenarios. Our MAC layer analytical model of IEEE 802.11p broadcast reveals the
quantitative relation between DCC parameters and congestion control effects in
closed-form solution for linear vehicular networks.
