Cellular Data Networks & Exploiting Opportunistic Scheduling

Third Generation (3G) cellular networks utilize time
varying and location-dependent channel conditions to
provide broadband services. They employ opportunistic
scheduling to efficiently utilize spectrum under fairness
or QoS constraints. Opportunistic scheduling algorithms
rely on collaboration among all mobile users
to achieve their design objectives. However, we demonstrate
that rogue cellular devices can exploit vulnerabilities
in opportunistic scheduling algorithms, such as
Proprotional Fair (PF), to usurp the majority of time
slots in 3G networks. Our simulations show that only
five rogue device per 50-user cell can use up to 90%
of the time slots, and can cause 2 seconds of end-to-end
inter-packet transmission delay on VoIP applications for
every user in the same cell, rendering VoIP applications
useless. To defend against these attacks, we explore several
detection and prevention schemes, including modifications
to the PF scheduler and a secure handoff procedure.