Interference Management for Femtocell Networks
Open Access
- Author:
- Guler, Basak
- Graduate Program:
- Electrical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 12, 2012
- Committee Members:
- Aylin Yener, Thesis Advisor/Co-Advisor
- Keywords:
- femtocells
interference management
interference alignment - Abstract:
- This thesis proposes methods for applying the idea of Interference Alignment (IA) in femtocell networks. In the first method, in order to manage the uplink interference caused by macrocell users (MU) at the femtocell base stations (FBS), cooperation between macrocell users with the closest femtocell base stations is used to align the received signals of macrocell users in the same subspace at multiple FBSs simultaneously. The proposed method achieves IA while providing the QoS requirements of macrocell users, in terms of minimum received SINR at the macrocell base station (MBS). With this approach, the BER performance of femtocell users is shown to improve, while maintaining the quality of the communication channel of macrocell users. In the second method, an interference limited multi-tier multiuser MIMO cellular uplink is considered. Specifically, an interference management scheme is proposed where interference from subsets of macrocell users is aligned at the femtocell base stations in order to ensure acceptable service for the femtocell users. The scheme employs interference alignment at each femtocell base station, to the set of macrocell users that are causing the high interference specifically at that FBS, and is termed selective IA. The proposed IA algorithm determines the interference subspaces at each FBS and precoders for each macrocell user in a distributed fashion.