Secure Resource Allocation for OFDMA Two-Way Relay Wireless Sensor Networks Without and With Cooperative Jamming

We consider secure resource allocations for orthogonal frequency division multiple access two-way relay wireless sensor networks. The joint problem of subcarrier assignment, subcarrier pairing and power allocations is formulated under scenarios of using and not using cooperative jamming to maximize the secrecy sum rate subject to limited power budget at the relay station and orthogonal subcarrier allocation policies. The optimization problems are shown to be mixed integer programming and non-convex. For the scenario without cooperative jamming, we propose an asymptotically optimal algorithm based on the dual decomposition method, and a suboptimal algorithm with lower complexity. For the scenario with cooperative jamming, the resulting optimization problem is non-convex, and we propose a heuristic algorithm based on alternating optimization. Finally, the proposed schemes are evaluated by simulations and compared to the existing schemes.