Abstract--Location area (LA) planning plays an important role in cellular networks because of the trade-off caused by paging and registration signaling. The upper bound on the size of an LA is the service area of a mobile switching center (MSC). In that extreme case, the cost of paging is at its maximum, but no registration is needed. On the other hand, if each cell is an LA, the paging cost is minimal, but the registration cost is the largest. In general, the most important component of these costs is the load on the signaling resources. Between the extremes lie one or more partitions of the MSC service area that minimize the total cost of paging and registration. In this paper, we try to find an optimal method for determining the location areas. For that purpose, we use the available network information to formulate a realistic optimization problem. We propose an algorithm based on simulated annealing (SA) for the solution of the resulting problem. Then, we investigate the quality of the SA technique by comparing its results to greedy search and random generation methods.

No abstract

No abstract

Abstract. We describe relay attacks on Bluetooth authentication protocol. The aim of these attacks is impersonation. The attacker does not need to guess or obtain a common secret known to both victims in order to set up these attacks, merely to relay the information it receives from one victim to the other during the authentication protocol run. Bluetooth authentication protocol allows such a relay if the victims do not hear each other. Such a setting is highly probable. We analyze the attacks for several scenarios and propose practical solutions. Moreover, we simulate attacks to make sure about their feasibility. These simulations show that current Bluetooth specifications do not have defensive mechanisms for relay attacks. However, relay attacks create a significant partial delay during the connection that might be useful for detection.

No abstract

No abstract

No abstract

No abstract