In mobile ad hoc networks (MANET), broadcasting is extensively used in route discovery, address resolution, and many other network services. The efficiency of broadcasting protocol can dramatically affect the performa...
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In mobile ad hoc networks (MANET), broadcasting is extensively used in route discovery, address resolution, and many other network services. The efficiency of broadcasting protocol can dramatically affect the performance of the entire network. Proper use of probabilistic method can reduce the number of rebroadcasting, therefore reduce the chance of contention and collision among neighboring nodes. A good probabilistic broadcast protocol can achieve high throughput and low energy consumption without suffering significant reachability degradation. In this paper, we propose a dynamic probabilistic approach and compare it with simple flooding and fixed probabilistic scheme. Our approach dynamically adjusts the rebroadcasting probability according to the node distribution and movement in the ad hoc network. The adaptation is based on locally available information without the assistance of location or distance measuring devices. Simulation results show our approach perform better than both simple flooding and fixed probabilistic schemes.
Wireless ad hoc networks present more security problems than the conventional wired and wireless networks. Intrusion detection, as a complementary mechanism to the regular intrusion prevention approaches, is needed to...
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Wireless ad hoc networks present more security problems than the conventional wired and wireless networks. Intrusion detection, as a complementary mechanism to the regular intrusion prevention approaches, is needed to secure the wireless ad hoc networks. In this paper we focus on the network layer security issues and propose a practical support vector machine (SVM) based intrusion detection system. The effectiveness of our proposed approach has been verified by extensive simulation results.
Bluetooth is a radio technology for wireless personal area networking (WPAN) operating in the 2.4 GHz ISM frequency band. The Bluetooth MAC protocol is based on the master/slave concept wherein any communication betwe...
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Bluetooth is a radio technology for wireless personal area networking (WPAN) operating in the 2.4 GHz ISM frequency band. The Bluetooth MAC protocol is based on the master/slave concept wherein any communication between slave devices has to go through the master. While this model provides for simplicity, it incurs longer delay between any two slave devices due to far from optimal packet forwarding, the use of double the bandwidth, and also it wastes additional energy at the master. Moreover, if more than two devices want to communicate as a group, this can only be achieved by either multiple unicast transmissions or a piconet-wide broadcast, clearly resulting in inefficiency. We propose a novel dynamic slot assignment (DSA) scheme whereby the master device dynamically assigns slots to slaves so as to allow them to communicate directly with each other without master intervention. This proposed mechanism also provides for quality of service (QoS) requests, and multi-device conversation by which a multicast-like communication is implemented within a piconet. Through extensive simulation, we observe that this mechanism greatly enhances Bluetooth performance in terms of delay and throughput while incurring extremely low overhead.
Bluetooth is a promising wireless technology aiming at supporting electronic devices to be instantly interconnected into short-range ad hoc networks. The Bluetooth medium access control protocol is based on the Master...
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As more and more people enjoy the various services brought by mobilecomputing, it is becoming a global trend in today’s world. At the same time, securing mobilecomputing has been paid increasing attention. In this ...
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The use of directional antennas in cellular wireless networks offers many advantages such as range extension, reduced interference for signal detection and improved throughput. MAC protocols using directional antennas...
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The use of directional antennas in cellular wireless networks offers many advantages such as range extension, reduced interference for signal detection and improved throughput. MAC protocols using directional antennas for wireless ad hoc networks that are based on and similar to IEEE 802.11 type WLANs have been proposed. We explore 'multiplexing in space' with directional antennas to enhance the total throughput at a bottleneck node in the network. We develop an access protocol for antenna systems that can transmit to multiple destinations simultaneously (and possibly receive from multiple sources as well). Some issues enabling multiple access in space for ad hoc network nodes are discussed. Our simulation results show that the current 802.11 MAC scheme using omnidirectional antennas for channel access fairs very poorly as the bandwidth demand increases. In contrast, we see substantial improvement when spatial multiplexing is employed.
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