Lossy Environment Research Articles

Energy based Efficiency Evaluation of Cluster-Based Routing Protocols for Wireless Sensor Networks (WSNs)

The design of routing protocols for wireless sensor network (WSN) is influenced by many challenging factors such as fault tolerance, energy efficiency, scalability, latency, power consumption and network topology etc. Among all of them the energy is often considered as primary resource constraint in a wireless sensor network. The main factors affecting energy consumption are: perceptual data, data processing and radio communications, the radio communication is the main part of energy consumption. Hence, energy conservation is one of the foremost priorities in the design of wireless sensor networks (WSNs) protocols having significant impact on the overall energy consumption. Recently, clustering routing techniques show their great attitude towards efficient data gathering by minimizing overall energy consumption as well as load balancing with improved network reliability and scalability. However, in harsh nature lossy wireless deployment all above mentioned advantages can not be achieved simultaneously by all routing schemes. Therefore, this paper examines the performance as well as energy consumption issues of the existing routing schemes by providing periodic data from a sensing field to a remote receiver in lossy wireless environment. So that, the network lifetime can be increased to reasonable times. We formulate the energy consumption and study their estimated lifetime based on varying parameters related to the sensing field, e.g., size, and distance etc. The simulation is conducted though the network simulation tool MATLAB7.0, over various routing schemes show that long distance communication, unnecessary multihop data transmission, data path looping, data redundancy, memory overflow, synchronization issues and inappropriate selection of MAC layer mechanism are the main challenging issues which leads to excessive data packet loss and consumes a significant amount of node energy in cluster based WSNs.

Generation of distributed entangled coherent states over a lossy environment with inefficient detectors

Entangled coherent states are useful for various applications in quantum information processing, but they are sensitive to loss. We propose a scheme to generate distributed entangled coherent states over a lossy environment in such a way that the fidelity is independent of the losses at detectors heralding the generation of the entanglement. We compare our scheme with a previous one for the same purpose [Ourjoumtsev et al., Nat. Phys. 5, 189 (2009)] and find parameters for which our scheme results in superior performance.

Editorial for Security and Privacy in Wireless Networks Special Issue

Editorial: This special issue features five invited papers from experts working in the area of wireless security and privacy. The first article, “Trust-based routing mechanism in MANET: Design and Implementation”, discusses the challenging issues in MANET routing security. The authors present FrAODV, a trustbased scheme for securing AODVrouting protocol inMANET using the friendship mechanism. In their proposed scheme the nodes can evaluate the routing paths according to some selected features (such as node reputation and identity information) before forwarding the data through these routes. They have used two types of implementation in their scheme, simulation (using NS-2) and a real test-bed (using JADHOC). The proposed scheme is believed to provide a robust environment where MANET nodes can trust each other in a secure community. The second article, entitled “Performance of IEEE 802.11 under Jamming”, studies the performance of the IEEE 802.11 MAC protocol under a range of jammers that covers both channel-oblivious and channel-aware jamming. The authors consider two channel-oblivious jammers: a periodic jammer that jams deterministically at a specified rate, and amemoryless jammer whose interfering signals arrive according to a Poisson process. They also develop new models for channel-aware jamming, including a reactive jammer that only jams noncolliding transmissions and an omniscient jammer that optimally adjusts its strategy according to current states of the participating nodes. The study comprises of a theoretical analysis of the saturation throughput of 802.11 under jamming, an extensive simulation study, and a testbed to conduct real world experimentation of jamming IEEE 802.11 using software defined radio (GNU Radio combined with USRP boards). In the third paper, “Adaptive Information Coding for Secure and Reliable Wireless Telesurgery”, a Telesurgical Robot System (TRS) is studied and the authors present a novel approach that uses information coding to integrate both light-weight privacy and adaptive reliability in a single protocol called Secure and Statistically Reliable UDP (SSR-UDP). They prove that the offered security is equivalent to the existing AES-based long key crypto systems, yet with significantly less computational overhead. They also demonstrate that the proposed scheme can meet high reliability and delay requirements of TRS applications in highly lossy environments while optimizing the bandwidth use. The fourth paper is entitled “Reverse authentication in financial transactions and identity management”, and the authors utilise the concept that new families of protocol, based on communication over human-based side channels, can permit secure pairing or group formation inways such that no party has to prove its name. In this model, individuals are able to hook up devices in their possession to others that they can identify by context. They examine a model in which, to prove his or her identity to a party, the user uses one of these human-interactive security protocols (or HISPs) to connect to it. Thus, when authenticating A to B, A authenticates a channel she has to B: the reverse direction. This can be characterised as bootstrapping a secure connection using human trust. This provides new challenges to the formal modelling of trust and authentication. In the fifth paper, titled “A privacy preserving method using privacy enhancing techniques for location based services”, the authors study the privacy issues relating to gathering of location information for non-trusted applications like locationbased marketing or user behaviour profiling. It shows how M. Rajarajan (*) Security Engineering, City University London, Northampton Square, EC1V 0HB London, UK e-mail: R.Muttukrishnan@city.ac.uk

Robust scalable video multi-cast with multiple sources and inter-source network decoding in lossy networks

This paper presents a robust scalable video multi-cast scheme with source diversity and inter-source network decoding in lossy networks. The source diversity technique gives path diversity, providing a better quality of layered video transmission under hostile environments. For each source, an optimization formulation is set up to find the best transmission route of each transmitting video layer. The objectives of the formulation are to maximize the total information values of video layers reflecting the end-to-end video quality and transmission reliability. The source providing the best overall achievable data rate, which is the data rate destination can expect to receive from the transmission, is selected to be the primary source, while the rest will be secondary sources. When the Quality-of-Service (QoS) guarantees of some transmitting video layers cannot be fulfilled by the primary source, the secondary source with the best QoS parameters is selected to transmit the layers to destinations. The number of secondary sources used for transmissions is increased until the QoS guarantees of all transmitting video layers are satisfied or all network resources are utilized. Network coding is deployed to multi-cast video layers from the same source for efficient resource usage. Network coded data from different sources can be used to decode the transmitting video data. In other words, at each destination, it needs only a sufficient number of video packets from different sources to recover all transmitting video data. Simulations with different network topologies show the improvement in both objective and subjective qualities of layered video multi-cast under lossy environments.

Low-ε Static Probe Development for15N-1H Solid-state NMR Study of Membrane Proteins for an 800 MHz NB Magnet

H heteronuclear dipolar coupling in dilute membrane proteins oriented in hydrated anddielectrically lossy lipid environments. The system employed a 800 MHz narrow-bore magnet. A solenoid coilstrip shield was used to reduce deleterious RF sample heating by minimizing the conservative electric fieldsgenerated by the double-tuned resonator at high magnetic fields. The probe's design, construction, andperformance in solid-state NMR experiments at high magnetic fields are described here. Such high-resolutionsolid-state NMR spectroscopic analysis of static oriented samples in hydrated phospholipid bilayers or bicellescould aid the structural analysis of dilute biological membrane proteins.Key Words : Solid-state NMR probe, Low- e, Probe design, Membrane proteins, BicellesIntroductionMembrane proteins are important in various essentialsystems and regulatory processes, ranging from the com-plicated network of cellular communications to the meta-bolism and breaking down of unwanted substances in thehuman body. Hundreds of diseases involve the mis-foldingor mis-assembling of integral membrane proteins and over60% of all drug molecules target membrane proteins.Despite their importance, these protein's intrinsic structure-function relationships are not understood as their three-dimensional structures have not been fully elucidated. Thestudy of membrane proteins by current methods is hamperedby the need of a native bilayer environment, which is diffi-cult using most biophysical techniques. They are notoriouslydifficult to crystallize for X-ray crystallography and theirslow reorientation rates when combined with lipids or deter-gents hinder the use of conventional solution NMR (NuclearMagnetic Resonance) techniques. Solid-state NMR spectroscopy is a relatively new meansof investigating the structures of solid biological samples.

A 6.0 GHZ SMALL PRINTED MONOPOLE ANTENNA FOR WIRELESS IMPLANTABLE BODY AREA NETWORK (WIBAN) APPLICATIONS

Wireless implantable body area network (WiBAN) is useful for monitoring vital human parameters in medical diagnosis such as breast cancer, heart attack and high blood pressure. The main objective of this paper is to design a small printed monopole antenna for WiBAN applications at 6.0GHz. The small implantable antenna was tested in a lossy environment by being submerged into canola oil that mimics the dielectric properties of human breast fat tissue. The antenna performances were measured by using vector network analyzer (VNA) in order to evaluate the return loss and operating bandwidth of the antenna. The other parameters such as e-ciency, radiation pattern and gain are evaluated by simulation of CST Studio 2012 software. When compared, there is good agreement between the simulation and measurement results. The simulated antenna gain and e-ciency are 5.8dBi and 97%, respectively, when submerged into canola oil. The antenna radiation pattern is directional, and it has 6 lobes implying its coverage in more directions which is of good beneflt due to body movement. The antenna's polarization was tested by placing a wideband antenna at several degrees around the proposed

Strategies for choosing path-entangled number states for optimal robust quantum-optical metrology in the presence of loss

To acquire the best path-entangled photon Fock states for robust quantum optical metrology with parity detection, we calculate phase information from a lossy interferometer by using twin entangled Fock states. We show that (a) when loss is less than 50% twin entangled Fock states with large photon number difference give higher visibility while when loss is higher than 50% the ones with less photon number difference give higher visibility; (b) twin entangled Fock states with large photon number difference give sub-shot-noise limit sensitivity for phase detection in a lossy environment. This result provides a reference on what particular path-entangled Fock states are useful for real world metrology applications.

Efficient Wireless Broadcasting through Joint Network Coding and Beamforming

We develop a framework that exploits network coding (NC) and multiple-input/multiple-output (MIMO) techniques, jointly together, to improve throughput of downlink broadcast channels. Specifically, we consider a base station (BS) equipped with multiple transmit antennas that serves multiple mobile stations (MSs) simultaneously by generating multiple signal beams. Given the large number of MSs and the small number of transmit antennas, the BS must decide, at any transmission opportunity, which group of MSs it should transmit packets to, in order to maximize the overall throughput. We propose two algorithms for grouping MSs that take advantage of NC and the orthogonality of user channels to improve the overall throughput. Our results indicate that the proposed techniques increase the achievable throughput significantly, especially in highly lossy environments.

Squeezed-state quantum key distribution upon imperfect reconciliation

We address the security of continuous-variable quantum key distribution with squeezed states upon the realistic conditions of noisy and lossy environment and limited reconciliation efficiency. Considering the generalized preparation scheme and clearly distinguishing between classical and quantum resources, we investigate the effect of finite squeezing on the tolerance of the protocol to untrusted channel noise. For a long-distance strongly attenuating channel and the consequent low reconciliation efficiency, we show that feasible limited squeezing is surprisingly sufficient to provide the security of Gaussian quantum key distribution in the presence of untrusted noise. We explain the effect by the behaviour of the Holevo quantity, which describes the information leakage and is effectively minimized by the squeezed states.

Visual Important-Driven Interactive Rendering of 3D Geometry Model over Lossy WLAN

In this paper, we propose a visual important-driven interactive rendering method for 3D model over 802.11 WLAN for overcoming the shortcomings of wireless network’s narrow bandwidth, high transmission error rates and mobile devices’ low power supply. This paper first proposes an efficient simplification method based on an improved visual important region detection technique. Then, we develop an efficient hybrid FEC and MAC-Lite model transmission protocol which will transmit the model data by their importance respectively. Finally, we propose a real-time interactive rendering method by an efficient model coding. Experimental results demonstrate that we can obtain better rendering result among lossy environment and gain real-time interactive rendering result.

Adaptive Information Coding for Secure and Reliable Wireless Telesurgery Communications

Telesurgical Robot Systems (TRSs) have been the focus of research in academic, military, and commercial domains for many years. Contemporary TRSs address mission critical operations emerging in extreme fields such as battlefields, underwater, and disaster territories. The lack of wirelined communication infrastructure in such fields makes the use of wireless technologies including satellite and ad-hoc networks inevitable. TRSs over wireless environments pose unique challenges such as preserving a certain reliability threshold, adhering some maximum tolerable delay, and providing various security measures depending on the nature of the operation and communication environment. In this study, we present a novel approach that uses information coding to integrate both light-weight privacy and adaptive reliability in a single protocol called Secure and Statistically Reliable UDP (SSR-UDP). We prove that the offered security is equivalent to the existing AES-based long key crypto systems, yet, with significantly less computational overhead. Additionally, we demonstrate that the proposed scheme can meet high reliability and delay requirements of TRS applications in highly lossy environments while optimizing the bandwidth use. Our proposed SSR-UDP protocol can also be utilized in similar cyber-physical wireless application domains.

Rate adaptation with loss diagnosis on IEEE 802.11 networks

SUMMARYRate adaptation in wireless networking aims to seek the optimal data transmission rate most appropriate for current wireless channel conditions to make full use of the channel potentials. It is important in wireless networks because (1) most of them support multiple data rates, and (2) wireless channel is unstable with fast changes on which a single rate thereby may not be proper for long. Based on a comprehensive survey of the rate adaptation for IEEE 802.1 networks in literature, this work proposes a rate adaptation scheme, dubbed effective rate adaptation (ERA), for IEEE 802.11 networks. ERA takes advantage of the fragmentation technique in IEEE 802.11 standard and utilizes the lowest rate retransmission in diagnosing frame loss cause (collision or channel degradation), diffusing collision, and promptly recovering frame losses. It also adopts an adaptive rate increase threshold concept to exploit channel potentials. Different from other rate adaptation schemes, ERA effectively addresses two challenges in rate adaptation on IEEE 802.11 networks: (1) it does not require RTS/CTS for loss diagnosis purpose; the use of RTS/CTS that are optional in IEEE standard results in inefficiency on channel utilization; (2) it promptly responds to frame failure due to channel degradation, unlike others waiting till the end of a transmission window or cycle. With extensive simulation, ERA shows its unique strength in different lossy environments, especially in collision‐prone environments. Copyright © 2011 John Wiley & Sons, Ltd.

Actively coupled cavity ringdown spectroscopy with low-power broadband sources.

We demonstrate a coupling scheme for cavity enhanced absorption spectroscopy that makes use of an intracavity acousto-optical modulator to actively switch light into (and out of) a resonator. This allows cavity ringdown spectroscopy (CRDS) to be implemented with broadband nonlaser light sources with spectral power densities of less than 30μW/nm. Although the acousto-optical element reduces the ultimate detection limit by introducing additional losses, it permits absorptivities to be measured with a high dynamic range, especially in lossy environments. Absorption measurements for the forbidden transition of gaseous oxygen in air at ∼760nm are presented using a low-coherence cw-superluminescent diode. The same setup was electronically configured to cover absorption losses from 1.8×10-8cm-1 to 7.5% per roundtrip. This could be of interest in process analytical applications.

Engineering TCP transmission and retransmission mechanisms for wireless networks

Transmission Control Protocol (TCP) provides mechanisms for reliable data communications. Although it works well in wired networks, it fails to offer satisfactory performance in lossy and wireless environments. And in the multi-hop wireless infrastructure, packet delivery suffers high cumulative loss rate if traveling over multiple wireless hops. The Selective acknowledgment (SACK) is one header option that might be used to combat segment corruptions in air channels. In this paper, an alternative set of flow control mechanisms is proposed to handle high packet loss rate in a wireless medium. Using a measurement-based mechanism, sustainable segment delivery is achievable through a novel size-reduction method. Multiple segment retransmission mechanisms are introduced to reduce successive timeout events. One single byte loss is sufficient to waste all other bytes in a file received at a destination. That is, a good TCP flow control mechanism should provide a high successful file transmission completion rate, and this is set as our design goal. Through thorough simulations, our proposed multi-segment retransmission designs perform with higher successful file transfer rate and fewer timeout events than NewReno and SACK under a wide range of packet loss probabilities.

An Objective Approach to Measuring Video Playback Quality in Lossy Networks using TCP

In this work, we investigate a new objective measurement for assessing the video playback quality for services delivered in networks that use TCP as a transport layer protocol. We define the new metric as pause intensity to characterize the quality of playback in terms of its continuity since, in the case of TCP, data packets are protected from losses but not from delays. Using packet traces generated from real TCP connections in a lossy environment, we are able to simulate the playback of a video and monitor buffer behaviors in order to calculate pause intensity values. We also run subjective tests to verify the effectiveness of the metric introduced and show that the results of pause intensity and the subjective scores made over the same real video clips are closely correlated.

Receiver-Assisted Congestion Control to Achieve High Throughput in Lossy Wireless Networks

Many applications would require fast data transfer in high-speed wireless networks nowadays. However, due to its conservative congestion control algorithm, Transmission Control Protocol (TCP) cannot effectively utilize the network capacity in lossy wireless networks. In this paper, we propose a receiver-assisted congestion control mechanism (RACC) in which the sender performs loss-based control, while the receiver is performing delay-based control. The receiver measures the network bandwidth based on the packet interarrival interval and uses it to compute a congestion window size deemed appropriate for the sender. After receiving the advertised value feedback from the receiver, the sender then uses the additive increase and multiplicative decrease (AIMD) mechanism to compute the correct congestion window size to be used. By integrating the loss-based and the delay-based congestion controls, our mechanism can mitigate the effect of wireless losses, alleviate the timeout effect, and therefore make better use of network bandwidth. Simulation and experiment results in various scenarios show that our mechanism can outperform conventional TCP in high-speed and lossy wireless environments.

Game-Theoretic Approach for Improving Cooperation in Wireless Multihop Networks

Traditional networks are built on the assumption that network entities cooperate based on a mandatory network communication semantic to achieve desirable qualities such as efficiency and scalability. Over the years, this assumption has been eroded by the emergence of users that alter network behavior in a way to benefit themselves at the expense of others. At one extreme, a malicious user/node may eavesdrop on sensitive data or deliberately inject packets into the network to disrupt network operations. The solution to this generally lies in encryption and authentication. In contrast, a rational node acts only to achieve an outcome that he desires most. In such a case, cooperation is still achievable if the outcome is to the best interest of the node. The node misbehavior problem would be more pronounced in multihop wireless networks like mobile ad hoc and sensor networks, which are typically made up of wireless battery-powered devices that must cooperate to forward packets for one another. However, cooperation may be hard to maintain as it consumes scarce resources such as bandwidth, computational power, and battery power. This paper applies game theory to achieve collusive networking behavior in such network environments. In this paper, pricing, promiscuous listening, and mass punishments are avoided altogether. Our model builds on recent work in the field of Economics on the theory of imperfect private monitoring for the dynamic Bertrand oligopoly, and adapts it to the wireless multihop network. The model derives conditions for collusive packet forwarding, truthful routing broadcasts, and packet acknowledgments under a lossy wireless multihop environment, thus capturing many important characteristics of the network layer and link layer in one integrated analysis that has not been achieved previously. We also provide a proof of the viability of the model under a theoretical wireless environment. Finally, we show how the model can be applied to design a generic protocol which we call the Selfishness Resilient Resource Reservation protocol, and validate the effectiveness of this protocol in ensuring cooperation using simulations.

Web Acceleration in Asymmetrical Mobile Network

End to end performance of web application degrades seriously in mobile networks because the inefficiencies of HTTP and TCP in lossy and asymmetrical environment. In this article, we discussed common architecture of web accelerator which embraces both HTTP and TCP optimization. Based on the feasibility analyses of various acceleration technologies in asymmetrical mobile network, the components of accelerator and their functions are provided. In order to explain how to choose function entities of accelerator and how to optimize their parameters in asymmetrical environment, we carried out three simulation based analyses. Firstly we characterize the correlations between user perceived web response time and asymmetrical link characteristics. Consequently, we show how HTTP compression strongly affects the web response time when uplink resources are limited. At the same time, our study demonstrated that caching scheme performs poorly when uplink quality degraded. In addition, possible potential methods for web response time and their design criteria are discussed.

A batched network coding scheme for wireless networks

Several wireless network coding schemes apply either inter-flow traffic or intra-flow traffic, but not both. This paper proposes a novel batched network coding scheme to deal with both inter-flow and intra-flow traffics, which attempts to combine the advantages of both network coding approaches. Based on the idea in the well-known network coding scheme COPE, our batched network coding scheme allows each node to make use of intra-flow network coding technique to improve the transmission reliability in a lossy environment, consequently obtaining higher throughput. Moreover, we also utilize the multiple-path transmitting scheme to further increase the throughput of wireless networks with low link delivery probability. Finally, using a simplified network topology model, we show theoretically that our proposed scheme outperforms COPE significantly, particularly when the link quality is low.

Optimized multipath network coding in lossy wireless networks

Network coding has been a prominent approach to a series of problems that used to be considered intractable with traditional transmission paradigms. Recent work on network coding includes a substantial number of optimization based protocols, but mostly for wireline multicast networks. In this paper, we consider maximizing the benefits of network coding for unicast sessions in lossy wireless environments. We propose optimized multipath network coding (OMNC), a rate control protocol that dramatically improves the throughput of lossy wireless networks. OMNC employs multiple paths to push coded packets to the destination, and uses the broadcast MAC to deliver packets between neighboring nodes. The coding and broadcast rate is allocated to transmitters by a distributed optimization algorithm that maximizes the advantage of network coding while avoiding congestion. With extensive experiments on an emulation testbed, we find that OMNC achieves more than two-fold throughput increase on average compared to traditional best path routing, and significant improvement over existing multipath routing protocols with network coding. The performance improvement is notable not only for one unicast session, but also when multiple concurrent unicast sessions coexist in the network.