Maintaining social links through ampiify-and-forward in wireless networks

It is critical to maintain the communication links between important social pairs. However, maintaining the social links between faraway nodes in wireless networks is extremely difficult. Although multi-hop transmission can be used, if two nodes in the routing path are out of the wireless transmission range, a network partition is possible. To address this problem, we adopt a cooperative amplify-and-forward strategy, where nodes (relays) cooperate to improve the signal strength at the destination. We formulate and study two optimization problems for maintaining the required link throughput: Min-Energy and Min-Relay, where the goal of Min-Energy is to minimize the power consumption of the relays, and the goal of Min-Relay is to minimize the number of active relays. Since the Min-Energy problem is a non-convex problem, we solve it based on an approximation technique and prove that our solution is a feasible, in fact optimal solution. We formulate the Min-Relay problem as an integer programming problem, and propose a polynomialtime algorithm which can select the minimum number of relays to maintain the social link. Evaluation results show that Min-Relay can significantly reduce the number of active relays compared to Min-Energy, while achieving comparable power consumption.