Maximal Packing with Interference Constraints
  In this work, we study the problem of scheduling a maximal set of transmitters subjected to an interference constraint across all the nodes. Given a set of nodes, the problem reduces to finding the maximum cardinality of a subset of nodes that can concurrently transmit without violating interference constraints. The resulting packing problem is a binary optimization problem and is NP hard. We propose a semi-definite relaxation (SDR) for this problem and provide bounds on the relaxation. 
Rakshith Jagannath, Radha Krishna Ganti and Neelesh S Upadhye
cs.IT math.IT stat.AP