Mitigating DoS Attacks on the Paging Channel by Efficient Encoding in Page Messages

Paging is an important mechanism for network bandwidth efficiency and mobile terminal battery life. It has been widely adopted by mobile networks, such as cellular networks, WiMax, and Mobile IP. Due to certain mechanisms for achieving paging efficiency and the convergence of wireless voice and data networks, the paging channel is vulnerable to inexpensive DoS attacks. To mitigate these attacks, we propose to leverage the knowledge of the user population size, the slotted nature of the paging operation, and the quick paging mechanism to reduce the length of terminal identifiers. In the case of a CDMA2000 system, we can reduce each identifier from 34 bits down to 7 bits, effectively doubling the paging channel capacity. Moreover, our scheme incurs no paging latency, missed pages, or false pages. Using a simulator and data collected from a commercial cellular network, we demonstrate that our scheme doubles the cost for DoS attackers.