Exploiting Opportunistic Scheduling in Cellular Data Networks

Abstract

Third Generation (3G) cellular networks utilize timevarying 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.