Cooperative Uplink Link Adaptation in 3GPP LTE Heterogeneous Networks

Heterogeneous Network (HetNet) where small cells served by Low Power Nodes (LPNs) are overlaid onto conventional macro cells is considered to meet the requirements of the increasing need for higher data rates. In this paper, we investigate the uplink interference situation in 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) HetNet and the corresponding impacts on the efficiency of UL link adaptation, with the focus on small cells. It is observed that the efficiency of UL link adaptation of LPN cells is seriously affected by a small number of dominant interferers. In addition, we study two Uplink Coordinated Multi-point (UL CoMP) schemes which exploit the fluctuation nature of UL interference strength to mitigate the influences. A simplified approach to perform cooperative link adaptation for HetNet is also addressed. System level simulations are carried out to evaluate these schemes, and promising performance gains are observed.