Control and data channel resource allocation in macro-femto Heterogeneous Networks

This paper investigates the downlink resource allocation problem in Orthogonal Frequency Division Multiple Access (OFDMA) Heterogeneous Networks (HetNets) consisting of macrocells and femtocells sharing the same frequency band. The focus is to devise an optimised policy for femtocells´ access to the shared spectrum, in terms of femtocell transmissions, in order to keep femto users sum data rate at high levels while ensuring that certain level of quality of service (QoS) for the macro-cell users in the vicinity of femtocells is provided. Both data and control channel constraints are considered, to insure that not only the macro-cell users´ data rate demands are meet, but also a certain level of Bit Error Rate (BER) is ensured for the control channel information. The problem is addressed by our proposed linear binary integer programming heuristic algorithm and the performance is compared with the conventional Reuse-1 scheme. Results show a negligible drop in femtocell performance for our proposed scheme, as a trade-off for ensuring all macro users data rate demands when Reuse-1 scheme can even lead up to 40% outage. Discussion is also presented for the implementation possibility of our proposed in a practical LTE network.