An improved graph coloring based small cell discovery scheme in LTE hyper-dense networks

Efficient discovery of multiple small cells is important to features such as small cell on/off, load balancing, CoMP (Coordinated Multi-point Transmission), e-ICIC (enhanced-Inter-Cell Interference Coordination) in LTE (Long Term Evolution) hyper-dense networks. However, severe interference in the Hyper-Dense Networks imposes great difficulty on efficient discovery of small cells. This paper proposes an improved graph coloring based scheme to facilitate the discovery of multiple small cells in Hyper-Dense Networks. Our proposed scheme is to divide small cells that are near to each other into different groups and let each group take turns to transmit synchronization signals so that interference between small cells are reduced. Graph coloring theory is employed in the division of small cells to guarantee that small cells within a certain distance are divided into different groups. Simulation results shows that using the proposed scheme detection probability of top 10 small cells is greatly improved compared to conventional scheme.