Protocol performance of UL/DL separation in LTE heterogeneous networks

The purpose of this paper is to study the performance of Uplink/Downlink (UL/DL) separation in a heterogeneously deployed LTE network. UL/DL separation refers here to the separation of uplink and downlink transmissions so that downlink data is received from the higher power macro nodes, whereas uplink data may be transmitted to closer located pico nodes. The simulation results show that UL/DL separation provides gains especially in uplink by up to 22% on average and 110% for cell-edge users, and the gains seem to be the highest with high system load. The main sources of the gains seem to be increased throughput due to a better uplink connection to a closer pico node and offloading traffic from a highly loaded macro cell to small cells.