Optimal intra-cell cooperation in the heterogeneous relay networks

Heterogeneous wireless networks have emerged as a new paradigm to meet the fast increasing wireless capacity and coverage demands. Cooperative communication is a promising technique to further improve the cell edge performance for future communication systems by allowing nodes in a communication network to collaborate with each other in information transmission. This paper presents an optimal intra-cell cooperative transmission in a relay based heterogeneous networks to best address both capacity and coverage demands. We first formulate the optimization problem to maximize the time averaged log-scale throughput. The Lagrange dual function is then derived for the proposed optimization problem, from which we use gradient descent method to search the optimal intra-cell cooperative transmission solution. Simulation results show that the optimal cooperative transmission can greatly improve the log-scale throughput in the heterogeneous networks with relays.