Co-channel interference avoidance in two-tier LTE femtocell systems using control information

Macrocell Base stations, called the Enhanced NodeB (eNB) are mainly aiming to serve outdoor users. However, due to insufficient signal strength this solution has difficulty in serving indoor users. To address this problem, the Femtocell, called the Home eNB(HeNB), system has been deployed in the LTE system. Since the HeNBs and the eNB use the same frequency band and the same frame structure, co-channel interference between HeNBs and eNB is unavoidable. To solve this problem, we propose a co-channel interference (CCI) avoidance scheme using the control information in the downlink subframe. Simulation results show the proposed scheme outperforms the conventional two-tier LTE femtocell systems in terms of the outage probability and the system throughput.