No abstract

As the cost of 802.11 hardware continues to fall, the appeal of inserting unauthorized wireless access into enterprise networks grows. These rogue access points (APs) expose the enterprise network to a barrage of security vulnerabilities in that they are typically connected to a network port behind the firewall. Most of the current approaches to detecting rogue APs are rudimentary and are easily evaded by hackers. We propose the use of temporal traffic characteristics to detect rogue APs at a central location. This detection is independent of the wireless technology (802.11a, 802.11b, or 802.11g), is scalable, does not posses the inefficiencies of the current solutions, and is independent of the signal range of the rogue APs. Globecom 2004

No abstract

Vehicle-to-Vehicle (V2V) communication is expected to make a global impact on improving driver safety by alerting motorists of potential collisions, but the full safety benefit can only be realized if every vehicle is equipped with a transceiver. Motivated to provide collision avoidance for drivers of vehicles only equipped with a V2V transceiver, we develop a framework for using the V2V communication signal simultaneously as a radar without suggesting any changes to the existing V2V standards or spectrum. The theoretical system treats the IEEE 802.11p waveform as a Multi-Frequency Continuous Wave signal to estimate the velocity and range of a vehicular threat not equipped with a V2V transceiver. While spectrum and upper layers of the protocol stack can vary depending on geographic region, the IEEE 802.11p physical layer protocol is adopted globally. Restrictions in waveform design due to IEEE 802.11p standardization are considered and leveraged for enhancing the radar operations. Through a rigorous simulation treatment, the V2V radar system would be capable of detecting a head-on collision with a 35.12% accuracy using only safety message packets. If non-safety packets are included in the detection operation, then up 100% accuracy is achievable.Index Terms-Vehicle-to-Vehicle, IEEE 802.11p, Collision Avoidance, OFDM Radar 978-1-4799-5952-5/15/$31.00 ©2015 IEEE

The wireless medium is a s=ce shared resource in mobde computing. Consequently, the media access control (MAC) layer influences the fairness and robustness of the wireless network. According to the current MAC protocok, stations are not able to gain access equdy to the shared wireless medium. This problem is conunody known as the fairness problem. The fairness problem occurs mostly bemuse of the existence of hidden stations and the presumption of a non-Wy connected wird=s network topology. This paper addresses solutions to the fairness problem in wireless networks. persistent carrier sense mdtiple access based dgr ithms are proposed in which a fair wirel=s access for each user is accomplished using a precsdtiated N acce~Probabfity, Pij, . .that represents the Eti access probabtity horn station i to j. Lii access probabfities are dcdated at the source station in two ways using connection-based and time-based media access methods. According to the used methods, each active user broadcasts information on either the number of Iogicd connections or the average cent ent ion time to the stations within the communication reach. This information exchange provides partird understanding of the topology of the network to the stations. Each station reserves a specific priority for itse~to gain access to the shared medium. It is suggested that the information is exchanged during the W access discovery procedure for the connection-based method, and periodidy for the time-based method. Link access probabtit ies are modified every time the exchanged information is received. The proposed algorithms are dynamic and sensitive to the changes in the network topology. The sdgoritb have been implemented in a specific media access control protocol [1], but they are app~mble to d media access control protocok.Simdation restits show that the algorithms restit in an order of magnitude performance improvement in terms of throughput in a wirel= network.