Sufficient rate constraints for QoS flows in ad-hoc networks

The capacity of an arbitrary ad-hoc network is difficult to estimate due to interference between the links. We use a conflict graph that models this interference relationship to determine if a set of flow rates can be accommodated. Using the cliques (complete subgraphs) of the conflict graph, we derive constraints that are sufficient for a set of flow rates to be feasible, yet are guaranteed to be within a constant bound of the optimal. We also compute an alternate set of sufficient constraints that can be easily derived from the rows of the matrix representation of the conflict graph. These two sets of constraints are particularly useful because their construction and verification may be distributed across the nodes of a network. We also extend the ad-hoc network model to incorporate variations in the interference range, and obstructions in the network.