Energy-Efficient Link Scheduling with Load Constraints in Dual-Hop 60GHz Wireless Networks

In 60 GHz wireless networks, relay-based dual-hop transmission is an effective solution to prolong the communication range and bypass the obstacles. However, it is very challenging to determine link scheduling in the dual-hop network architecture while considering several factors, such as reducing network power consumption and avoiding overloaded APs/relays. Here, we investigate the problem of energy-efficient link scheduling with load constraints (ELL). Firstly, we present a fine-grained energy model for dual-hop 60 GHz wireless networks, and formulate the ELL problem as an integer linear programming (ILP) model that aims to minimize the network power consumption with AP/relay load constraints. Then, we propose a polynomial time algorithm that obtains a near-optimal link scheduling solution via iterative relaxation, and the load constraint of each AP/relay can only be violated by at most an additive constant of two. Finally, we conduct simulation experiments that validate our algorithm's effectiveness and efficiency.