Hop-Based dynamic fair scheduler for wireless Ad-Hoc networks

In a typical multihop Ad-Hoc network, interference and contention increase when flows transit each node towards destination, particularly in the presence of cross-traffic. This paper observes the relationship between throughput and path length, self-contention and interference and it investigates the effect of multiple data rates over multiple data flows in the network. Drawing from the limitations of the 802.11 specification, the paper proposes a scheduler named Hop Based Multi Queue (HBMQ), which is designed to prioritise traffic based on the hop count of packets in order to provide fairness across different data flows. The simulation results demonstrate that HBMQ performs better than a Single Drop Tail Queue (SDTQ) scheduler in terms of providing fairness. Finally, the paper concludes with a number of possible directions for further research, focusing on cross-layer implementation to ensure the fairness is also provided at the MAC layer. © 2013 IEEE

IoT Security Vulnerabilities and Predictive Signal Jamming Attack Analysis in LoRaWAN

Internet of Things (IoT) gains popularity in recent times due to its flexibility, usability, diverse applicability and ease of deployment. However, the issues related to security is less explored. The IoT devices are light weight in nature and have low computation power, low battery life and low memory. As incorporating security features are resource expensive, IoT devices are often found to be less protected and in recent times, more IoT devices have been routinely attacked due to high profile security flaws. This paper aims to explore the security vulnerabilities of IoT devices particularly that use Low Power Wide Area Networks (LPWANs). In this work, LoRaWAN based IoT security vulnerabilities are scrutinised and loopholes are identified. An attack was designed and simulated with the use of a predictive model of the device data generation. The paper demonstrated that by predicting the data generation model, jamming attack can be carried out to block devices from sending data successfully. This research will aid in the continual development of any necessary countermeasures and mitigations for LoRaWAN and LPWAN functionality of IoT networks in general

Queue utilization with hop based enhanced arbitrary inter frame spacing MAC for saturated ad HOC networks

© 2015 IEEE. Path length of a multi hop Ad Hoc networks has an adverse impact on the end-to-end throughput especially during network saturation. The success rate of forwarding packets towards destination is limited due to interference, contention, limited buffer space, and bandwidth. Real time applications streaming data fill the buffer space at a faster rate at the source and its nearby forwarding nodes since the channel is shared. The aim of this paper is to increase the success rate of forwarding the packets to yield a higher end-to-end throughput. In order to reduce loss of packets due to buffer overflow and enhance the performance of the network for a saturated network, a novel MAC protocol named Queue Utilization with Hop Based Enhanced Arbitrary Inter Frame Spacing based (QU-EAIFS) MAC is proposed for alleviating the problems in saturated Ad Hoc networks. The protocol prioritises the nodes based on its queue utilization and hops travelled by the packet and it helps achieving higher end-toend performance by forwarding the packets with higher rate towards the destination during network saturation. The proposed MAC enhances the end-to-end performance by approximately 40% and 34% for a 5hop and 6hop communication respectively in a chain topology as compared to the standard IEEE802.11b. The performance of the new MAC also outperforms the performance of IEEE 802.11e MAC. In order to validate the protocol, it is also tested with short hops and varying packet sizes and more realistic random topologies

Dynamic Queue Utilization Based MAC for multi-hop Ad Hoc networks

The end-to-end throughput in single flow multi-hop Ad Hoc networks decays rapidly with path length. Along the path, the success rate of delivering packets towards the destination decreases due to higher contention, interference, limited buffer size and limited shared bandwidth constraints. In such environments the queues fill up faster in nodes closer to the source than in the nodes nearer the destination. In order to reduce buffer overflow and improve throughput for a saturated network, this paper introduces a new MAC protocol named Dynamic Queue Utilization Based Medium Access Control (DQUB-MAC). The protocol aims to prioritise access to the channel for queues with higher utilization and helps in achieving higher throughput by rapidly draining packets towards the destination. The proposed MAC enhances the performance of an end-to-end data flow by up to 30% for a six hop transmission in a chain topology and is demonstrated to remain competitive for other network topologies and for a variety of packet sizes

Hacking NHS Pacemakers: A Feasibility Study

Pacemakers are common types of implants, in recent years there have been growing concerns around the security within these devices. This paper was created with the assistance of the NHS staff at NGH, it attempts to answer the question of if it is feasible to hack current models of NHS pacemakers. The experiments performed were done so in the mindset of an average hacker, not a team of experts with access to the required knowledge and equipmen

Location based transmission using a neighbour aware-cross layer MAC for ad hoc networks

In a typical Ad Hoc network, mobile nodes have scarce shared bandwidth and limited battery life resources, so optimizing the resource and enhancing the overall network performance is the ultimate aim in such network. This paper proposes anew cross layer MAC algorithm called Location Based Transmission using a Neighbour Aware – Cross Layer MAC (LBT-NA Cross Layer MAC) that aims to reduce the transmission power when communicating with the intended receiver by exchanging location information between nodes in one hand and on the other hand the MAC uses a new random backoff values, which is based on the number of active neighbour nodes, unlike the standard IEEE 802.11 series where a random backoff value is chosen from a fixed range of 0-31. The validation test demonstrates that the proposed algorithm increases battery life, increases spatial reuse and enhances the network performance

Dynamic neighbour aware power-controlled MAC for multi-hop ad hoc networks

In Ad Hoc networks, resources in terms of bandwidth and battery life are limited; so using a fixed high transmission power limits the durability of a battery life and causes unnecessary high interference while communicating with closer nodes leading to lower overall network throughput. Thus, this paper proposes a new cross layer MAC called Dynamic Neighbour Aware Power-controlled MAC (Dynamic NA -PMAC) for multi-hop Ad Hoc networks that adjust the transmission power by estimating the communication distance based on the overheard signal strength. By dynamically controlling the transmission power based on the receivable signal strength, the probability of concurrent transmission, durability of battery life and bandwidth utilization increases. Moreover, in presence of multiple overlapping signals with different strengths, an optimal transmission power is estimated dynamically to maintain fairness and avoid hidden node issues at the same time. In a given area, since power is controlled, the chances of overlapping the sensing ranges of sources and next hop relay nodes or destination node decreases, so it enhances the probability of concurrent transmission and hence an increased overall throughput. In addition, this paper uses a variable backoff algorithm based on the number of active neighbours, which saves energy and increases throughput when the density of active neighbours is less. The designed mechanism is tested with various random network scenarios using different traffic including CBR, Exponential and TCP in both scenarios (stationary and mobile with high speed) for single as well as multi-hop. Moreover, the proposed model is benchmarked against two variants of power-controlled mechanisms namely Min NA-PMAC and MaxRC-MinDA NA-PMAC to prove that using a fixed minimum transmission power may lead to unfair channel access and using different transmission power for RTS/CTS and Data/ACK leads to lower probability of concurrent transmission respectively

Will Blockchain technology become a reality in sensor networks?

The need for sensors to deliver, communicate, collect, alert, and share information in various applications has made wireless sensor networks very popular. However, due to its limited resources in terms of computation power, battery life and memory storage of the sensor nodes, it is challenging to add security features to provide the confidentiality, integrity, and availability. In order to communicate reliably with trust and authenticity, providing data and system security especially for those sensors dealing with sensitive data related to healthcare, military activity, environmental sensing for weather prediction or seismic data etc. is vital. Blockchain technology ensures security and avoids the need of any trusted third party for security. However, applying Blockchain in a resource-constrained wireless sensor network is a challenging task because Blockchain is power, computation, and memory hungry in nature and demands heavy bandwidth due to control overheads. In this paper, a new routing and a private communication Blockchain framework is designed and tested with sensors generating constant and continuous data (like voice and video). However, it is realized that even if computation and bandwidth requirements are taken for granted, storage and battery life will cripple the sustainability of Blockchain application in sensor networks especially for high data generating sensors. The proposed Load Balancing Multi- Hop (LBMH) routing shares and enhances the battery life of the Cluster Heads and reduce control overhead during Block updates, but due to limited storage and energy of the sensor nodes, Blockchain in sensor networks may never be a reality unless storage and battery life of sensor devices are not limited on the one hand and computation power and bandwidth availability are high, on the other

Location based transmission using a neighbour aware with optimized EIFS MAC for ad hoc networks

In a typical Ad Hoc network, participating nodes have scarce shared bandwidth and limited battery life resources, so resource optimization and enhancing the overall network performance are the primary aims to maintain functionality. This paper proposes a new cross layer Medium Access Control (MAC) algorithm called Location Based Transmission using a Neighbour Aware with optimized Extended Inter-Frame Spacing (EIFS) for Ad Hoc Networks MAC (LBT-NA with optimized-EIFS MAC) that aims to reduce the transmission power when communicating with the next hop receiver based on node’s location which is made available during node deployment. However, node mobility is not taken into account in the study of this paper. According to the algorithm the node dynamically adjusts its transmission power, if there is an active neighbour located beyond the communicating source and destination pair to avoid hidden nodes. The new protocol also defines an optimized EIFS when frame collision, frame error or frame capture takes place, in-order to maintain a fair channel access among the contending nodes. The proposed MAC also uses a modified range of random backoff values, based on the degree of contention unlike IEEE 802.11 series which uses a fixed random backoff value for fresh frames irrespective of the degree of contention. Simulation results indicate that in a random topology with a random source and destination, when the two sources are separated by a minimum distance of 200m, the performance gain of power controlled MAC over IEEE 802.11b ranges from 30% to 70% depending on the type of traffics in the network and the degree of fairness ranges from 62% to 99.99% for a location based MAC with minimum power transmission, whereas LBT-NA with optimized-EIFS MAC secures fairness index ranging from 75% to 99.99%. Communication with a node that is 20m away can save 40% of the battery life in comparison to the traditional transmission power MAC from 802.11b. The validation tests demonstrate that the proposed algorithm increases battery life and reduces the interference impact on shorter distance communication and increases the probability of parallel transmission. The proposed protocol also provides a scope for active nodes to transmit with a higher degree of probability, providing higher degree of overall network throughput in the environment and alleviate the starvation of hidden node by using Dynamic EIFS scheme

Multidimensional: User with File Content and Server’s status based Authentication for Secure File Operations in Cloud

The popularity of data storage in cloud servers is getting more and more favoured in recent times. Its ease of storage, availability and synchronization of personalized cloud file storage using client applications made cloud storage more popular than ever. In cloud storage system, using a basic authentication method like username and password are still one of the most popular forms of authentication. However, the security ensure by such traditional authentication method is weak and vulnerable because the user name and password can be compromised by intruders or the user account can be left open by forgetting to logoff in public computers, leading to exposure of information to unauthorised users and hackers. In recent years, using a two-factor authentication has become a trend throughout network-based cloud services, online banking system and any form of services that requires user authentication. Here, in this paper a second layer authentication in the form of session key is used to ensure the authenticity of the activities of the user after user’s web-based account is logged-in successfully. The interesting and the critical contribution in this paper is the way the session key is generated and delivers to the authentic user. The key is generated by using the hash value of the file content, file size, file last modified, pseudo-random generated by the server using CPU temperature, clock speed, system time, and network packet timings, and user based 8 digit random position selection from a 32 digit Hex to mitigate against the attacker while performing vital file activities which may lead to data lost or data destruction or when user’s credentials are compromised