Auction based spectrum sharing for hybrid access in macro-femtocell networks under QoS requirements

This paper studies the spectrum sharing framework for motivating the hybrid access in the two-tier macro-femtocell networks. The power allocation of each user equipment (UE) is subject to its quality-of-service (QoS) requirement as a function of the signal-to-interference plus noise ratio (SINR). The macro base station (MBS) offloads the macro UEs (MUEs) to the femto access points (FAPs) in order to improve the energy efficiency of the entire system since certain MUEs are closer to the FAP(s) than to the MBS. When multiple femtocells exist in the network, auction mechanism is appropriate to establish the hybrid access. Each FAP bids for serving extra MUEs while the MBS acts as the auctioneer. In order to reduce the overhead of the information exchange, we assume that the FAPs decide their bids independently of each other by maximizing their own utilities. After receiving the bids, the MBS searches the winner FAP(s) and optimizes the number of offloaded MUEs. The compensation fee based on the bid is paid by the MBS to the winner FAP(s) for serving the additional MUEs. Numerical results show that the lowest bidder wins the auction. The proposed auction for motivating the hybrid access in the two-tier macro-femtocell network results in a win-win solution since both utilities of the MBS and FAPs are maximized.