Femtocell as a Relay with Application of Physical Layer Network Coding

This study takes advantage of the ability of Physical-Layer Network Coding (PNC) to embrace electromagnetic interference, improve spectral efficiency and achieve throughput optimality in a femtocell operated as a relay. Specifically, we make a case for a femtocell operating as a relay and utilizing PNC to eliminate the interference that exists between macrocells user equipments (MUEs) and femtocells home users equipments (HUEs) in an Opened Subscriber Group (OSG) co-channel deployment. With PNC implemented at the HNB relay, it becomes possible for the relay to take advantage of the information signals transmitted from both the HUE and MUE rather than treating the MUE's signals as interference. To guarantee the Service Quality (QoS) of femtocell users, we develop the closed-form expressions of the cummulative distributions function (CDF) of the received signal-to-noise ratios (SNR) and the outage probability of the HUE analytically. Simulation results match the analytical results and it is demonstrated that PNC is suitable for a relay operated femtocell network.