the achievable rate of a K-user interference channel with single antenna at individual node is studied. Interference alignment and zero forcing are applied at the transmitter and receiver, respectively. It is well known from the paper [1] of

Shortest Path, Traveling Salesman and Hamiltonian Cycle are the other network design problem. These problems are very common to back bone network design problem. In all these three problems, the main difference is the degree of the node whic