Selection of transmission points for delay minimization in LTE-A heterogeneous networks with low-power RRHs

Heterogeneous network with small cells has recently been regarded as a promising scenario in LTE-Advanced systems. In particular, transmission point selection for heterogeneous networks with low-power nodes has drawn attention. We consider in this paper a scenario where a set users is admitted to a macrocell, but it is yet to be determined how each user is served solely or cooperatively by the set of subordinate transmission points in the cell. Unlike related work that focuses on maximizing the system throughput, we formulate a joint optimization problem of transmission point selection and resource allocation to minimize the total transmission delay of users in the cell. The formulated problem is NP-hard, and thus we propose an algorithm based on overlapping clustering and Gibbs sampler for solving the problem. Simulation results show that, compared to related approaches, the total transmission delay can be reduced by 34% and the Jain´s fairness index can be increased to 0.9 on average.