Biblio

As we all know, network coding can significantly improve the throughput and reliability of wireless networks. However, in the high-speed mobile environment, the packet loss rate of different wireless links may vary greatly due to the time-varying network state, which makes the adjustment of network coding redundancy very important. Because the network coding redundancy is too large, it will lead to excessive overhead and reduce the effective throughput. If the network coding redundancy is too small, it will lead to insufficient decoding, which will also reduce the effective throughput. In the design of multi-path transmission scheduling scheme, we introduce adaptive redundancy network coding scheme. By using multiple links to aggregate network bandwidth, we choose appropriate different coding redundancy for different links to resist the performance loss caused by link packet loss. The simulation results show that when the link packet loss rate is greatly different, the mechanism can not only ensure the transmission reliability, but also greatly reduce the total network redundancy to improve the network throughput very effectively.

Nowadays, an increasing trend to use autonomous Unmanned Aerial Vehicles (UAV) for applications like logistics as well as security and surveillance can be recorded. Autonomic UAVs require robust and precise navigation to ensure efficient and safe operation even in strong multipath environments and (intended) interference. The need for robust navigation on UAVs implies the necessary integration of low-cost, lightweight, and compact array antennas as well as structures for multipath mitigation into the UAV platform. This article investigates a miniaturized antenna array mounted on top of vertical choke rings for robust navigation purposes. The array employs four 3D printed elements based on dielectric resonators capable of operating in all GNSS bands while compact enough for mobile applications such as UAV.

From recent few years, need of information security is realized by society amd researchers specially in multi-path, unstructured networks as Mobile Ad-hoc Network. Devices connected in such network are self-configuring and small in size and can communicate in infra less environment. Architecture is very much dynamic and absence of central controlling authority puts challenges to the network by making more vulnerable for various threats and attacks in order to exploit the function of the network. The paper proposes, TCP analysis against very popular attack i.e. blackhole attack. Under different circumstance, reliable transport layer protocol TCP is analyzed for the effects of the attack on adhoc network. Performance has been measured using metrics of average throughput, normalized routing load and end to end delay and conclusions have been drawn based on that.

In infrastructure wireless network technology, communication between users is provided within a certain area supported by access points (APs) or base station communication networks, but in ad-hoc networks, communication between users is provided only through direct connections between nodes. Ad-hoc network technology supports mobility directly through routing algorithms. However, when a connected node is lost owing to the node's movement, the routing protocol transfers this traffic to another node. The routing table in the node that is receiving the traffic detects any changes that occur and manages them. This paper proposes a routing protocol method that sets up multi-hops in the ad-hoc network and verifies the performance, which provides more effective connection persistence than existing methods.

Device-free localization of people and objects indoors not equipped with radios is playing a critical role in many emerging applications. This paper presents an accurate model-based device-free localization system LiFS, implemented on cheap commercial off-the-shelf (COTS) Wi-Fi devices. Unlike previous COTS device-based work, LiFS is able to localize a target accurately without offline training. The basic idea is simple: channel state information (CSI) is sensitive to a target's location and by modelling the CSI measurements of multiple wireless links as a set of power fading based equations, the target location can be determined. However, due to rich multipath propagation indoors, the received signal strength (RSS) or even the fine-grained CSI can not be easily modelled. We observe that even in a rich multipath environment, not all subcarriers are affected equally by multipath reflections. Our pre-processing scheme tries to identify the subcarriers not affected by multipath. Thus, CSIs on the "clean" subcarriers can be utilized for accurate localization. We design, implement and evaluate LiFS with extensive experiments in three different environments. Without knowing the majority transceivers' locations, LiFS achieves a median accuracy of 0.5 m and 1.1 m in line-of-sight (LoS) and non-line-of-sight (NLoS) scenarios respectively, outperforming the state-of-the-art systems. Besides single target localization, LiFS is able to differentiate two sparsely-located targets and localize each of them at a high accuracy.