LAUSR

Deployed long term evolution-advanced (LTE-A) infrastructure may need coverage extension due to the exponential growth of mobile broadband data usages as well as poor network performance along the cell edges. A proper installation of relay nodes (RN) extends the network coverage in LTE-A networks. We propose an energy efficient and optimal RN placement (EEORNP) algorithm that maximizes the network coverage under the energy constraint, while maintaining the signal-to-interference ratio. The algorithm is based on an improved greedy algorithm, where an effective and optimal RN placement is guaranteed when the matroid rank function of the energy efficient coverage extension optimization is sub-modular and monotonic. The performance is investigated in terms of coverage percentage and number of RN needed to cover users. Results show that the proposed EEORNP outperforms both greedy and random placement algorithms.