  In heterogeneous cellular network, task scheduling for computation offloading
is one of the biggest challenges. Most works focus on alleviating heavy burden
of macro base stations by moving the computation tasks on macro-cell user
equipment (MUE) to remote cloud or small-cell base stations. But the
selfishness of network users is seldom considered. Motivated by the cloud edge
computing, this paper provides incentive for task transfer from macro cell
users to small cell base stations. The proposed incentive scheme utilizes small
cell user equipment to provide relay service. The problem of computation
offloading is modelled as a two-stage auction, in which the remote MUEs with
common social character can form a group and then buy the computation resource
of small-cell base stations with the relay of small cell user equipment. A
two-stage auction scheme named TARCO is contributed to maximize utilities for
both sellers and buyers in the network. The truthful, individual rationality
and budget balance of the TARCO are also proved in this paper. In addition, two
algorithms are proposed to further refine TARCO on the social welfare of the
network. Extensive simulation results demonstrate that, TARCO is better than
random algorithm by about 104.90% in terms of average utility of MUEs, while
the performance of TARCO is further improved up to 28.75% and 17.06% by the
proposed two algorithms, respectively.
