Mobility Prediction for Directional Networking

Since multi-hop mobile ad hoc network (MANET) contains a set of wireless mobile nodes forming a temporary network, the topology is strongly influenced by the node mobility models. Numerous mobility models have been presented, including the Random Waypoint Mobility Model (RWMM), Manhattan Grid Mobility Model (MGMM), Freeway Mobility Model (FMM), and so on. In MGMM, the trajectories of mobile nodes are confined to a grid topology. MGMM is an important mobility model, and numerous objects following MGMM can be enumerated, such as the movement of cars in the city, the movement of people though department stores etc. The expected link life time (ELLT) is an important performance parameter in MANET. When a node wishes to transmit information to the other node directly, these two nodes must be within each other's transmission range for a period of time. This period is called the link life time (LLT). The ELLT is the expected value of LLT. The goal of this work largely focuses on identifying the ELLT of the MANET under MGMM by using mathematical analysis. Based on our observation, two nodes involved in constructing a connection under MGMM can be classified into three independent cases: namely parallel with opposite directions, parallel with same directions, and vertical cases. These three cases can be formulated independently. To verify these formulations numerous simulations are done by ns2, and the theoretical and simulation results are well matched.

The radio access network (RAN) cache is recently proposed to improve quality of experience perceived by mobile users on Internet content access and reduce intense pressure on the backhaul network. However, because RAN caches (e.g., associated with base stations) are located below mobility management entities in mobile core network, the continuity of content service for the handover users with unfinished RANcache content transmission is destroyed. Thus motivated, we design the seamless RAN-cache handover framework based on mobility prediction algorithm (MPA), where the smart terminal with unfinished content service during mobility predicts the break and the target handover access node (such as the BS or the WiFi access point), and pre-triggers the source RAN cache to return the content service to CDN servers outside the core network (CN) or to notify the RAN cache associated with the target handover access node to prepare for serving the handover user. The framework incurs no change to cellular infrastructure including RAN and CN. Different from prior arts of assumption that users' mobility is pre-known, we design the parallel autoregressive (AR) based received signal strength (RSS) prediction approach to achieve mobility prediction, and mathematically define its false probability during different tolerant intervals. The simulation scenario deployment engine and the user movement engine are designed, considering practical issues. Through simulations, the the false probability of seamless RAN-cache handover pre-trigger through MPA is less than 1.36%, and it can be guaranteed less than 1% as the maximal RAN-cache handover processing time is increased by 8%.

Personal communication services (PCS) promise to be the telecommunications wave of the future. Ubiquity and mobility are key aspects of PCS which are particularly attractive to the military. Also, PCS systems using digital spread spectrum technology can provide the military with performance in the areas of security and low probability of intercept (LPI)/low probability of detection (LPD). Given that current policy is advocating the use of commercial equipment and systems wherever possible, it is appropriate that DOD contractors investigate the use of and incorporate commercial off-the-shelf (COTS) equipment as much as possible and where appropriate. The mobile subscriber equipment (MSE) provided by GTE represents the largest investment in tactical communication systems the Army has undertaken. Preservation of this investment through the use of judicious product improvement in times of stringent military budgets is of utmost importance. MSE consists of a number of node center switches, large and small extension nodes, line of sight equipment, and mobile subscriber terminals. Access to the small extension nodes (SENs) of the MSE switches is via field wire. Providing a wireless access to the SENs via commercial PCS equipment will greatly enhance the performance and warfighting capability of MSE. Thus, GTE has established a program whose objectives are the integration of commercial PCS with MSE.

Covert wireless communication is designed to securely transmit hidden information between two devices. Its primary objective is to conceal the existence of transmitted data, rendering communication signals difficult for unauthorized parties to detect, intercept, or decipher during transmission. In this paper, we propose a Noise-like Multi-Carrier Random Phase Communication System (NRPCS) to enhance covert wireless communication by significantly complicating the detection and interception of transmitted signals. The proposed system utilizes bipolar modulation and Cyclic Code Shift Keying (CCSK) modulation, complemented by a random sequence generation mechanism, to increase the randomness and complexity of the transmitted signals. A mathematical model of the NRPCS waveform is formulated, and detailed analyses of the system's time-domain basis functions, correlation properties, and power spectral characteristics are conducted to substantiate its noise-like behavior. Simulation results indicate that, compared to traditional fixed-frequency transmission methods, NRPCS substantially improves both the Low Probability of Detection (LPD) and the Low Probability of Interception (LPI). Further research results demonstrate that unauthorized eavesdroppers are unable to effectively demodulate signals without knowledge of the employed modulation scheme, thus significantly enhancing the overall security of communication.

The Submarine . . . The Road Ahead document establishes the desired capabilities of the submarine in extending its reach and becoming a fully netted node within network-centric operations. As a network node, the submarine can receive, process, and share mission-critical distributed sensor data. Additionally, submarines can act as platforms for the deployment of submarine tactical unmanned aerial vehicles (STUAVs). STUAVs extend the capability to communicate critical data and deploy off-board sensor systems. Acting as a 'system administrator' of unattended ground sensors (UGS), the submarine extends its support to special operating forces (SOF) and clandestine intelligence surveillance and reconnaissance (ISR) in access-denied areas. The submarine's stealthy long on-station presence provides for a non-provocative observation of adversary actions on land using unattended ground sensor systems which detect, monitor, and communicate targets of interest. The intent of this paper is to review the needed capability to maximize UGS capability while minimizing volume. UGS system deployment from a STUAV must be packaged in such a manner that the UGS system 1) will be a feasible payload of the STUAV, 2) will be deployed as part of a network grid, 3) will be embedded in the ground, 4) will support the needed duration, and 5) will be camouflaged for low probability of detection (LPD) and low probability of interception (LPI). Once deployed, UGS capabilities to detect, monitor, and relay information will provide another cued asset for intelligence, surveillance, reconnaissance and targeting (ISRT).

The ability of autonomous or semi-autonomous mobile robots to rapidly and accurately predict their mobility characteristics is an important requirement for their use in unstructured environments. Most methods for mobility prediction, however, assume precise knowledge of environmental (i.e. terrain) properties. In practical conditions, significant uncertainty is associated with terrain parameter estimation from robotic sensors, and this uncertainty must be considered in a mobility prediction algorithm. Here a method for efficient mobility prediction based on the stochastic response surface approach is presented that explicitly considers terrain parameter uncertainty. The method is compared to a Monte Carlo-based method and simulations show that the stochastic response surface approach can be used for efficient, accurate prediction of mobile robot mobility.

Recent research reveals that information security and information-hiding capabilities can be enhanced by proper exploitation of space-time techniques. Meanwhile, intrinsic properties of ultra wideband (UWB) signals make it an outstanding candidate for secure applications. In this paper, we propose a unitary space-time coding scheme for impulse radio UWB systems. Its transmission secrecy, including low probability of intercept (LPI), low probability of detection (LPD) and anti-jamming performance, is analyzed. Theoretical and simulation results show its superiority in wireless secure communications over other concurrent schemes.

The research works on the mobile ad hoc networks (MANET) have attracted wide attentions over the past few years. In order to evaluate and verify the underlying protocols or applications, researchers run simulations to generate results. By controlling different simulation parameters, we can run our programs in diverse simulation scenarios. Mobility model of mobile nodes in MANET plays an important role in simulations but its importance is often ignored. Random waypoint (RWP) is one of the most deployed mobility models in papers. RWP has the properties that are understandable and quick to implement. Until recently, several defects in RWP is unknown. One is decaying average speed and another is border effect. Besides the problems in RWP, there is still a missing property in many mobility models. Diverse average speed (DAS) is a more realistic requirement for mobility models. Most mobility models only can generate one average speed scenario with the same speed range. It is reasonable to provide different average speed within the same speed range. We propose general ripple mobility model (GRMM) of speed-time pairing to provide a similar mobility model to RWP without the defects of RWP. GRMM also provides DAS to generate different mobility scenarios. The simulation results show that GRMM of speed-time pairing can generate the mobility pattern of uniform spatial distribution and diverse average speed.

A Mobile Ad hoc NETwork (MANET) is a collection of wireless mobile nodes forming a network without using any existing infrastructure. All mobile nodes function as mobile routers that discover and maintain routes to other mobile nodes of the network and therefore, can be connected dynamically in an arbitrary manner. The mobility attribute of MANETs is a very significant one. The mobile nodes may follow different mobility patterns that may affect connectivity, and in turn protocol mechanisms and performance. Mobility prediction may positively affect the service-oriented aspects as well as the application-oriented aspects of ad hoc networking. At the network level, accurate node mobility prediction may be critical to tasks such as call admission control, reservation of network resources, pre-configuration of services and QoS provisioning. At the application level, user mobility prediction in combination with user’s profile may provide the user with enhanced location-based wireless services, such as route guidance, local traffic information and on-line advertising. In this chapter we present the most important mobility prediction schemes for MANETs in the literature, focusing on their main design principles and characteristics.

Mobility models are used to evaluate the network protocols of the ad hoc network using the simulation. The random waypoint model is a model for mobility that is usually used for the performance evaluation of ad-hoc mobile networks. Mobile nodes have dynamic mobility in the ad hoc network, so the mobility model plays an important role to evaluate the protocol performance. In this article, we developed modify random waypoint mobility (MRWM) model based on a random waypoint for the mobile ad hoc network. In this article, the comparative analysis of modifying random waypoint mobility and random waypoint model on the ad hoc On-Demand Distance Vector (AODV) routing protocol has been done for a large wireless ad hoc network (100 nodes) with the random mobile environment for the 1800s simulation time. To enhance the confidence in the protocol widespread simulations were accomplished under heavy traffic (i.e. 80 nodes) conditions. The proposed model protocol has been investigated with the performance metrics: throughput; packet delivery ratio; packet dropping ratio; the end-to-end delay and normalized routing overhead. The obtained results revealed that the proposed modified random waypoint mobility model reduces the mobility as compared to the random waypoint mobility model and it is trace is more realistic.

Traditionally the radiation beams of phased array antennas are formed by linearly shifting the phases of the transmitted waveforms from the antenna array elements, and the antenna beams can be scanned from one direction to another by subsequently changing the waveform phases [1, 2]. Digitally forming receiving antenna beams can be implemented by digitally filtering the received signals at array elements and have been widely used. However, digitally forming virtual transmitting beams or both transmitting and receiving beams has been very technically challenging. Yet there are many potential advantages for employing virtual transmitting beams rather than real phased array antenna beams. For example, in forming virtual transmitting antenna beams, the radiation energy of the antenna is not physically focused in any particular direction and thus is very difficult to be detected. As a result, the virtual radiating system can operate in a dasiasilentpsila mode with an extremely low probability of interception (LPI). Because the virtual radiation beam is formed through digital filtering of the received signals, the formed beams are more accurate and concentrated for intended radiation direction compared with phased array antenna beams. In addition, with virtual radiation systems, multiple transmitting-receiving beams can be generated simultaneously. In this work, we propose an innovative approach to forming virtual digital antenna beams (VDAB) by transmitting and processing orthogonal coding waveforms. The principle and architecture of the proposed system will be introduced and some simulated results will be presented to demonstrate the feasibility of the new systems.

A novel spread spectrum (SS) system based on the unconventional self encoding principle has been proposed for highly secured data transmissions. This system inherits the antijamming (AJ) and low probability of interception (LPI) characteristics like any other SS system with the aid of truly random spreading codes, which are generated from the source stream itself. Therefore, the proposed system is unique in that the traditional transmit and receive PN code generators are not needed. In fact, the enhanced transmission security arises not only due to the SS nature of the signal, but also from the true randomness of the unique spreading processes. This paper describes the proposed system and presents the simulation results of the system performance under various kinds of jamming conditions, which is not been so far dealt. The obtained performance curves are compared with existing SS systems like direct sequence and frequency hopped SS.

<p>Mobile Ad Hoc Network (MANET) consists of a group of mobile or wireless nodes that are placed randomly and dynamically that causes the continual change between nodes. A mobility model attempts to mimic the movement of real mobile nodes that change the speed and direction with time. The mobility model that accurately represents the characteristics of the mobile nodes in an ad hoc network is the key to examine whether a given protocol. The aim of this paper is to compare the performance of four different mobility models (i.e. Random Waypoint, Random Direction, Random walk, and Steady-State Random Waypoint) in MANET. These models were configured with Optimized Link State Routing (OLSR) protocol under three QoS (Quality of Service) <a title="Learn more about Metrics" href="https://www.sciencedirect.com/topics/engineering/metrics">metrics</a> such as the Packet Delivery Ratio (PDR), Throughput, End-to-End delay. The simulation results show the effectiveness of Steady-State Random Waypoint Mobility Models and encourage further investigations to extend it in order to guarantee other QoS requirements.</p>

Based on the asymptotic spectral distribution of sample covariance matrix, a new low probability of interception (LPI) signal detection method for multi-antenna intercept receiver is proposed via reforming the noise sequence into a Wishart matrix. The authors deduce the asymptotic cumulative distribution function (CDF) of eigenvalues of sample covariance matrix. Also a numerical Kullback–Leibler divergence of the empirical spectral CDF based on test samples from the deduced asymptotic CDF is established, which is treated as the test statistic. By comparing with other signal detection methods, simulation results show the new LPI signal detection method is superior and robust.

Free-space optical communication channels offer secure links with low probability of interception and detection. Despite their point-to-point topology, additional security features may be required in privacy-critical applications. Encryption can be achieved at the physical layer by using quantized values of photons, which makes exploitation of such quantum communication links extremely difficult. One example of such technology is keyed communication in quantum noise, a novel quantum modulation protocol that offers ultra-secure communication with competitive performance characteristics. Its utilization relies on specific coherent measurements to decrypt the signal. The process of measurements is complicated by the inherent and irreducible quantum noise of coherent states. This problem is different from traditional laser communication with coherent detection; therefore continuous efforts are being made to improve the measurement techniques. Quantum-based encryption systems that use the phase of the signal as the information carrier impose aggressive requirements on the accuracy of the measurements when an unauthorized party attempts intercepting the data stream. Therefore, analysis of the secrecy of the data becomes extremely important. In this paper, we present the results of a study that had a goal of assessment of potential vulnerability of the running key. Basic results of the laboratory measurements are combined with simulation studies and statistical analysis that can be used for both conceptual improvement of the encryption approach and for quantitative comparison of secrecy of different quantum communication protocols.