By Prof. Jeff Andrews
Femtocells will be assuming a massive role in expanding the capabilities of today’s cellular networks, and enabling them to satisfy people’s increasing demands for anytime, anywhere data. A femtocell is basically a small base station that people put in their home and attach to their wired internet connection just like a wireless LAN. However, it works just like a base station and seamlessly allows roaming, voice calls, and the increasing number of things people like to do with their cell phones.
Femtocells pose major technical issues, and if not deployed and designed correctly, could flood the already-strained cellular network with interference. For example, if a normal cell phone user is located close (say 100 feet) to a femtocell but transmitting to a base station that is farther away (typically 1000-5000 feet), its large transmission power causes crippling interference to the femtocell and renders it unusable. Perhaps even more crucially, the mirror effect can knock out cell phones and hence cause service interruptions.
Prof. Andrews’s group has been at the forefront of femtocell research since 2005 and has worked jointly with the CTO of Texas Instruments to model the interference issues and develop practical solutions. Together, they have authored the earliest and most-cited papers on the topic, including two “best papers” in top-flight IEEE conferences and a number of patents at UT and TI that develop interference avoidance and cancellation techniques at the physical and network layers.
For more information, please consult the following documents and links: