Resource Management For Traffic Offloading With Secrecy-provisioning In Cellular Networks:Research And Realization

The increasing popularity of mobile intelligent terminal and mobile internet has led to the explosive growth data traffic of cellular access network.The recent paradigm of small cell dual-connectivity(DC)emerges as a promising solution to facilitate mobile users'(MUs')traffic offloading in heterogeneous networks.With DC,a MU can flexibly schedule its traffic to macro-cell base station(mBS)and simultaneously offload data to small-cell access point(sAP).However,during traffic offloading,a malicious node might intentionally eavesdrop the MUs offloaded data by receiving the MU's radio signal,leading to the secrecy exposure.In this paper,we investigate the optimal resource allocation for the MUs' traffic offloading via DC with guaranteed secrecy.The mian part and contributions of this paper are as follows:First,we study a single-MU single-sAP case and formulate a joint optimization of the MU's traffic scheduling,power allocation,and bandwidth usage for traffic offloading.The formulation aims to minimize the MU's overall resource usage including the power consumption and bandwidth usage,while satisfying the MU's secrecy requirement and traffic demand.Despite the nonconvexity of the joint optimization problem,we decompose it to a top problem and a bottom problem.The bottom problem aims to optimize the traffic scheduling and power allocation,and we transform it to a convex optimization.The top problem aims to optimize the bandwidth usage,and we transform it to a monotonic optimization.Furthermore,we propose an efficient algorithm to compute the optimal offloading solution.Numerical results validate the performance of our proposed algorithm compared to that obtained by LINGO and show that the optimal offloading can significantly reduce computation time(up to 96%of computation time saving)Second,by using the single-MU's optimal offloading solution,we study the multi-MU multi-sAP case and formulate an optimal offloading-selection problem,i.e.,which MUs select which sAPs to form the DC pairs for traffic offloading.The formulation aims to maximize the overall served MUs' throughput while satisfying each served MU's traffic demand and secrecy requirement.It also takes into account the mBS's and sAPs' limited bandwidths and the sAPs'limited backhaul capacities.Since the formulated optimal offloading-selection problem corresponds to a multiple-resource generalized assignment problem which is NP-hard,we propose an efficient heuristic algorithm to compute the offloading-selection solution.Numerical results show the optimal solution improves the total served throughput more than 30%compared to some heuristic distance-based offloading scheme.Finally,we realize both the offloading scheme of single-MU single-sAP case and multi-sAP case on the MATLAB GUI(Graphical User Interfaces)platform.The users only need to enter the network parameters,and the GUI platform will show the offloading solutions.