In this paper we investigate the resiliency to jamming of data protocols, such as IP, over WLAN. We show that, on existing WLAN, an adversary can successfully jam data packets at a very low energy cost. Such attacks allow a set of adversary nodes disseminated over an area to prevent communication, partition an ad hoc network, or force packets to be routed over adversary chosen paths. The ratio of the jamming pulses duration to the transmission duration can be as low as 10--4. We investigate and analyze the performance of using various coding schemes to improve the robustness of wireless LANs for IP packets transmission. A concatenated code that is simple to decode and can maintain a low Frame Error Rate (FER) under a jamming effort ratio of 15%. We argue that LDPC codes will be very suitable to prevent this type of jamming. We investigate the theoretical limits by analyzing the performance derived from upper bounds on binary error-control codes. We also propose an efficient anti-jamming technique for IEEE802.11b.

We introduce a notion of universality in the context of optimization problems with partial information. Universality is a framework for dealing with uncertainty by guaranteeing a certain quality of goodness for all possible completions of the partial information set. Universal variants of optimization problems can be defined that are both natural and well-motivated. We consider universal versions of three classical problems: TSP, Steiner Tree and Set Cover.We present a polynomial-time algorithm to find a universal tour on a given metric space over

In this paper, we investigate the resiliency to jamming of data protocols, such as IP, over WLAN. We show that, on existing WLAN, an adversary can successfully jam data packets at a very low energy cost. Such attacks allow a set of adversary nodes disseminated over an area to prevent communication, partition an ad hoc network or force packets to be routed over adversary chosen paths. The ratio of the jamming pulses duration to the transmission duration can be as low as 10−4. We investigate and analyze the performance of combining a cryptographic interleaver with various coding schemes to improve the robustness of wireless LANs for IP packets transmission 1. A concatenated code that is simple to decode and can maintain a low frame error rate (FER) under a jamming effort ratio of 15%. We argue that LDPC codes will be very suitable to prevent this type of jamming. We investigate the theoretical limits by analyzing the performance derived from upper bounds on binary error‐control codes. We also propose an efficient anti‐jamming technique for IEEE802.11b based on Reed–Solomon codes. Copyright © 2004 John Wiley & Sons, Ltd.

In this paper we address the problem of secure multicast of data streams over a multihop wireless ad hoc network. We propose a dynamic multicast group management protocol that aims at solving problems that are specific to ad hoc networks such as mobility, unreliable links, and cost of multihop communication.The main idea is to have group members actively participate to the security of the multicast group, therefore reducing the communication and computation load on the source. Since the group security is distributed among the group members, we propose a service right certificate, to verify that a node is authorized to join the group, and also a corresponding revocation mechanism. We simulated our protocol within the ns-2 environment under various mobility, group size, and group dynamic scenarios. Our simulation results indicate that the communication cost and join delay of the protocol scale well when the group dynamic and nodes mobility increase. We have implemented the basic protocol in our ad hoc network testbed. We also proposed an extension to the basic secure multicast tree using multi-link capability combined with a k-out-of-N coding approach.

No abstract

In this paper we address the problem of secure multicast of data streams over a multihop wireless ad hoc network. We propose a key management protocol that aims at solving problems that are specific to ad hoc networks such as mobility, unreliable links, and multihop communication cost. The main idea is to have group members actively participate to the multicast group security therefore reducing the communication and computation load on the source. We also extend the proposed basic secure multicast tree using multi-link capability combined with a k-out-of-N coding approac. Since the group security is distributed among the group members we propose a service right certificate to verify that a node is authorized to join the group and also corresponding revocation mechanism. We simulated our protocol within the ns-2 environment under various mobility, group size, and group dynamic scenarios. Our preliminary simulation results indicate that the communication cost and join delay of the protocol scale well when the group size and nodes mobility increase.