  This paper investigates the downlink scheduling for relay-aided high-mobility
vehicular networks, where the vehicles with good vehicle-to-infrastructure
(V2I) links are employed as cooperative relay nodes to help the ones with poor
V2I links forward information via vehicle-to-vehicle (V2V) links. In existing
works, instantaneous achievable information rate was widely adopted to perform
the link scheduling, but it is not efficient for vehicular networks, especially
for high-mobility scenarios. Different from them, in this paper, we introduce
the mobile service to describe the mobile link capacity of vehicular networks
and then we propose a mobile service based relaying scheduling (MSRS) for high
mobility vehicular networks. In order to explore the system information
transmission performance limit, we formulate an optimization problem to
maximize the mobile service amount of MSRS by jointly scheduling the V2I and
V2V links. Since it is a combinational optimization problem which is too
complex to solve, we design an efficient algorithm with low-complexity for it,
where Sort-then-Select, Hungarian algorithm and Bisection search are employed.
Simulation results demonstrate that our proposed MSRS is able to achieve the
optimal results with an optimal approximation ratio larger than 96.5%. It is
also shown that our proposed MSRS is much more efficient for high-mobility
vehicular systems, which can improve the system average throughput with
increment of 3.63% compared with existing instantaneous achievable information
rate based scheduling method, and with 15% increment compared with traditional
non-cooperation scheduling method, respectively.
