Content placement for minimizing transmission cost in multiple cloud radio access networks

In this paper, the issue of content placement in multiple Cloud Radio Access Networks (CRANs) is addressed. In a CRAN, the contents are placed into the facilities of remote radio heads (RRHs) and baseband unit (BBU) pools to improve the performance of the content transmission. We aim to approach the objective of minimizing the total cost of content transmission to the users of multiple CRANs by considering joint content placement and storage allocation of RRHs and BBU pools. The problem is formulated as mixed-integer linear programming (MILP), which will be solved by a proposed algorithm in utilizing the rounding technology. We prove that the proposed algorithm can obtain the feasible solution of the MILP and has a competitive approximation ratio to the MILP. Further, the simulation results also validate that its solution obtained is very close to the optimal one of the MILP.