In a radio network, a denial-of-service attack or an attach storm after a temporary outage may cause severe access network overload. Unavailability of radio network services for its subscribing users causes dissatisfaction among the users and should be prevented. The problem is likely to become even more acute with the growth of Internet-of-Things applications that are expected to support critical infrastructure. In this paper, we present a new random access procedure based on tunable puzzles. Tunable puzzles provide the means to balance the load on the access network, prioritize certain devices, and localize radio resources for subsequent transmissions. By tuning the difficulty of puzzles, a base station can control the period of time before a device can send its next message. The prioritization by means of puzzles creates considerably less extra load on the base station compared to other alternatives, e.g. by using authentication. Encoding of radio resources in the puzzle solution enables a more efficient use of communication and processing resources. In addition, it gives malicious devices no incentive to guess the solution, since any solution other than the intended one fails to convey the information enabling the device to proceed further.
['Mats Näslund', 'Elena Dubrova', 'Göran Selander', 'Fredrik Lindqvist']
A random access procedure based on tunable puzzles