Engineering Commons^™

Modelling Challenges And Attacks To Wireless Networks, Dongsheng Zhang, Santosh Ajith Gogi, Dan S. Broyles, Egemen K. Çetinkaya, James P. G. Sterbenz

Egemen K. Çetinkaya

A thorough understanding of the network behaviour when exposed to challenges is of paramount importance to construct a resilient MANET (mobile ad hoc network). However, modelling mobile and wireless networks as well as challenges against them is non-trivial due to dynamic and intermittent connectivity caused by channel fading and mobility of the nodes. We treat MANETs as time-varying graphs (TVGs) represented as a weighted adjacency matrix, in which the weights denote the link availability. We present how centrality-based attacks could affect network performance for different routing protocols. Furthermore, we model propagation loss models that represent realistic area-based challenges in wireless …

Next Generation Wireless Communications: Cognitive Radio, Adnan Quadri, Naima Kaabouch

ADNAN QUADRI

Eavesdropping Security In Wireless Ad Hoc Networks With Directional Antennas, Qiu Wang, Hong-Ning Dai, Qinglin Zhao

Hong-Ning Dai

The eavesdropping security of wireless ad hoc networks has attracted considerable attention recently. However, most of current studies only consider OMN networks, where each node is mounted with a single omni-directional antenna, which radiates radio signals in all directions and consequently leads to the high eavesdropping possibility. Compared with an omnidirectional antenna, a directional antenna can concentrate the radio signals on some desired directions so that it can potentially reduce the eavesdropping possibility. This paper investigates the eavesdropping security of wireless ad hoc networks equipped with directional antennas. In particular, we study the eavesdropping possibility of OMN networks, SDA networks …

An Overview Of Using Directional Antennas In Wireless Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

Compared with omni-directional antennas, directional antennas have many merits, such as lower interference, better spatial reuse, longer transmission range and the improved network capacity. Directional antennas enable numerous emerging outdoor and indoor applications, which have been addressed in many recent studies. Despite the advances in wireless networks with directional antennas (DAWNs), there are many research challenges in all layers of DAWNs. This paper presents a detailed study on recent advances and open research issues on DAWNs. Firstly, we briefly introduce the classification of directional antennas, antenna radiation patterns, antenna modes as well as the challenges in the physical layer of …

On Eavesdropping Attacks In Wireless Sensor Networks With Directional Antennas, Hong-Ning Dai, Qiu Wang, Dong Li, Raymond Chi-Wing Wong

Hong-Ning Dai

The eavesdropping attack is a serious security threat to a wireless sensor network (WSN) since the eavesdropping attack is a prerequisite for other attacks. Conventional WSNs consist of wireless nodes equipped with omnidirectional antennas, which broadcast radio signals in all directions and are consequently prone to the eavesdropping attacks. Different from omnidirectional antennas, directional antennas radiate radio signals on desired directions and potentially reduce the possibility of the eavesdropping attacks. In this paper, we propose a model to analyze the eavesdropping probability in both single-hop WSNs and multihop WSNs with omnidirectional antennas and directional antennas. We verify the correctness of …

Spatio-Temporal Techniques For Anti-Jamming In Embedded Wireless Networks, Rahul Mangharam, Miroslav Pajic

Rahul Mangharam

Electromagnetic jamming results in a loss of link reliability, increased energy consumption and packet delays. In the context of energy-constrained wireless networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This coordination results in statistical and predictable activity patterns that may be easily detected and jammed. To eliminate spatio-temporal patterns of communication in the link and network layers, we present WisperNet, an energy-efficient anti-jamming protocol.WisperNet employs hardware-based time synchronization and lightweight cryptographic hashing for coordinated temporal randomization of slot schedules at the link layer and adapts routes to avoid static jammers …

On The Connectivity Of Wireless Networks With Multiple Directional Antennas, Hong-Ning Dai

Hong-Ning Dai

The network connectivity is one of important measures of the performance of wireless networks. However, most of current studies on the network connectivity only consider either an SOMN network, where each node is mounted with a single omni-directional antenna, or an SDA network, where each node is mounted with a single directional antenna. Using multiple directional antennas instead of a single directional antenna can potentially improve the network performance. In this paper, we investigate the connectivity of a novel network, in terms of an MDA network, where each node is mounted with multiple directional antennas. We found that MDA networks …

Link Scheduling In Multi-Transmit-Receive Wireless Networks, Hong-Ning Dai, Soung Chang Liew, Liqun Fu

Hong-Ning Dai

This paper investigates the problem of link scheduling to meet traffic demands with minimum airtime in a multitransmit-receive (MTR) wireless network. MTR networks are a new class of networks, in which each node can simultaneously transmit to a number of other nodes, or simultaneously receive from a number of other nodes. The MTR capability can be enabled by the use of multiple directional antennas or multiple channels. Potentially, MTR can boost the network capacity significantly. However, link scheduling that makes full use of the MTR capability must be in place before this can happen. We show that optimal link scheduling …

Exploring Security Improvement Of Wireless Networks With Directional Antennas, Hong-Ning Dai, Dong Li, Raymond Chi-Wing Wong

Hong-Ning Dai

There are a number of studies on using directional antennas in wireless networks. Many of them concentrate on analyzing the theoretical capacity improvement by using directional antennas. Other studies focus on designing proper Medium Access Control (MAC) protocols to improve the practical network throughput. There are few works on the security improvement using directional antennas. In this paper, we explore the benefits of directional antennas in security improvements on both singlehop and multi-hop wireless networks. In particular, we found that using directional antennas in wireless networks can significantly reduce the eavesdropping probabilities of both single-hop transmissions as well as multi-hop …

Throughput And Delay In Wireless Sensor Networks Using Directional Antennas, Hong-Ning Dai

Hong-Ning Dai

Most of studies only consider that wireless sensor networks are equipped with only omni-directional antennas, which can cause high collisions. It is shown that the per node throughput in such networks is decreased with the increased number of nodes. Thus, the transmission with multiple short-range hops is preferred to reduce the interference. However, other studies show that the transmission delay increases with the increased number of hops.

In this paper, we consider using directional antennas in wireless sensor networks. We have found that using directional antennas not only can increase the throughput capacity but also can decrease the delay by …

Collision-Tolerant Transmission With Narrow-Beam Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu, Bo Li

Hong-Ning Dai

The application of directional antennas in wireless ad hoc networks brings numerous benefits, such as increased spatial reuse and mitigated interference. Most MAC protocols with directional antennas are based on the RTS/CTS mechanism which works well in wireless ad hoc networks using omni-directional antennas. However, RTS/CTS frames cannot mitigate the interference completely. Besides, they also contribute a lot to the performance overhead. This paper studies the problem from a new perspective. We have found that the transmission success probability under directional transmission and directional reception is quite high when the antenna beamwidth is quite narrow. Motivated by the analytical results, …

On Collision-Tolerant Transmission With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

The application of directional antennas in wireless networks brings numerous benefits, such as increased spatial reuse and mitigated interferences. Most MAC protocols with directional antennas are based on the RTS/CTS mechanism which works well in wireless networks using omni-directional antennas. However, RTS/CTS frames cannot mitigate the interfering nodes completely. Besides, they also contribute a lot to the performance overhead. This paper studies the problem from a new perspective. We analyze the transmission success probability under directional transmission and directional reception when the antenna beamwidth is quite narrow. Motivated by the analytical results, we design a lightweight MAC protocol without RTS/CTS …

On The Capacity Of Multi-Channel Wireless Networks Using Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Raymond Chi-Wing Wong, Min-You Wu

Hong-Ning Dai

The capacity of wireless ad hoc networks is affected by two key factors: the interference among concurrent transmissions and the number of simultaneous transmissions on a single interface. Recent studies found that using multiple channels can separate concurrent transmissions and greatly improve network throughput. However, those studies only consider that wireless nodes are equipped with only omnidirectional antennas, which cause high collisions. On the other hand, some researchers found that directional antennas bring more benefits such as reduced interference and increased spatial reuse compared with omnidirectional antennas. But, they only focused on a single-channel network which only allows finite concurrent …

A Busy-Tone Based Mac Scheme For Wireless Ad Hoc Networks Using Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

Applying directional antennas in wireless ad hoc networks offers numerous benefits, such as extended communication range, increased spatial reuse, improved capacity and suppressed interference. However, directional antennas can cause new location-dependent carrier sensing problems, such as new hidden terminal and deafness problems, which can cause severe penalties to the performance. Recently, a few schemes have been proposed to tackle these problems. However, these methods can provide limited solutions on the hidden terminal and deafness problems. We propose a new MAC protocol, termed the busy-tone based directional medium access control (BT-DMAC) protocol. When the transmission is in progress, the sender and …

An Overview Of Mac Protocols With Directional Antennas In Wireless Ad Hoc Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

Although directional antennas have been used in mobile communications systems for quite a long time, realistic applications of directional or smart antennas in wireless ad hoc network have emerged just in recent years. Directional antennas provide numerous benefits, such as higher gains, increased transmission range and low interferences. Wireless medium access schemes play a crucial role in ensuring the efficient and fair sharing of wireless resources. Therefore there are many research work on mechanisms at the wireless medium access layer by using directional antennas. The new features of MAC with directional antennas can cause not only location dependent carrier sensing …