Dynamic Protected-Subframe Density Configuration in LTE Heterogeneous Networks

The protected-subframe (PSF) structure is one of the methods for downlink inter-cell interference coordination (ICIC) utilized in heterogenous networks and is featured in Rel-10 of the technical specification for 3GPP´s E-UTRAN. Static configuration of PSF has proven to increase performance but the dynamic configuration is yet to be examined. In this paper, we study the effect of dynamically configuring PSF density according to a certain criterion in an attempt to increase system performance and maintain a quality of service for all users. Results show that with full buffer traffic, the impact of dynamic configuration is more noticeable in cases of large pico cell range expansions. With dynamic traffic, we find that in the majority of cases, dynamic configuration outperforms the static. In this paper we consider two forms of PSF known as almost blank subframes (ABS) and reduced power subframes (RPS) and show the results from implementing both these techniques.