  Vehicular communications have stringent latency requirements on
safety-critical information transmission. However, lack of instantaneous
channel state information due to high mobility poses a great challenge to meet
these requirements and the situation gets more complicated when packet
retransmission is considered. Based on only the obtainable large-scale fading
channel information, this paper performs spectrum and power allocation to
maximize the ergodic capacity of vehicular-to-infrastructure (V2I) links while
guaranteeing the latency requirements of vehicular-to-vehicular (V2V) links.
First, for each possible spectrum reusing pair of a V2I link and a V2V link, we
obtain the closed-form expression of the packets' average sojourn time (the
queueing time plus the service time) for the V2V link. Then, an optimal power
allocation is derived for each possible spectrum reusing pair. Afterwards, we
optimize the spectrum reusing pattern by addressing a polynomial time solvable
bipartite matching problem. Numerical results show that the proposed queueing
analysis is accurate in terms of the average packet sojourn time. Moreover, the
developed resource allocation always guarantees the V2V links' requirements on
latency.
