  Coexistence between the dedicated short-range communications (DSRC) and other
wireless technologies needs thorough study since the United States legislative
bodies still remain undecided on the shared use of the 5.9 GHz band
(5.850-5.925 GHz). If the band is decided to be shared among multiple
technologies, the DSRC is expected to experience a performance degradation even
in safety-critical application. As such, it is a natural question how much the
performance degradation will be. However, it is not trivial to precisely model
the behaviors of a vehicular-to-everything (V2X) network since it requires to
formulate both spatial and temporal aspects in concert while the network
topology keeps dynamic due to the nodes' mobility. Moreover, DSRC relies on
broadcast of basic safety messages (BSMs) for supporting safety-critical
applications. Most prior work uses performance metrics such as packet delivery
rate (PDR) and packet delay, which cannot accurately capture the performance of
DSRC broadcasts. To this end, this paper (i) provides a comprehensive analysis
framework formulating both spatial and temporal factors in concert and (ii)
proposes a new performance metric that can more accurately characterize the
broadcast performance of a DSRC network. Based on the new metric, the results
present (i) the fundamental performance of a DSRC network under inter-RAT
interference from Wi-Fi and C-V2X and (ii) provide suggestions on optimal
selection of networking parameters.
