  In this paper, we consider a dense vehicular communication network where each
vehicle broadcasts its safety information to its neighborhood in each
transmission period. Such applications require low latency and high
reliability, and thus, we propose a non-orthogonal multiple access scheme to
reduce the latency and to improve the packet reception probability. In the
proposed scheme, the BS performs the semi-persistent scheduling to optimize the
time scheduling and allocate frequency resources in a non-orthogonal manner
while the vehicles autonomously perform distributed power control. We formulate
the centralized scheduling and resource allocation problem as equivalent to a
multi-dimensional stable roommate matching problem, in which the users and
time/frequency resources are considered as disjoint sets of players to be
matched with each other. We then develop a novel rotation matching algorithm,
which converges to a q-exchange stable matching after a limited number of
iterations. Simulation results show that the proposed scheme outperforms the
traditional orthogonal multiple access scheme in terms of the latency and
reliability.
