45 research outputs found

    Access and Routing in Aeronautical Ad-hoc Networks

    Get PDF
    National audienceAeronautical Ad hoc NETworks (AANET) have been proposed in previous studies as an alternative to cellular or satellite transmissions for “datalink” communications between commercial aviation aircraft in flight and air traffic services on the ground. After an introduction on the specificities of civil aviation communications, we present the channel access and routing challenges for AANETs. We finally propose an innovative communication architecture for AANETs

    On the Design of MAC Protocols for Multi-Packet Communication in IEEE 802.11 Heterogeneous Networks Using Adaptive Antenna Arrays

    Get PDF
    This paper discusses the design requirements for enabling multiple simultaneous peer-to-peer communications in IEEE 802.11 asynchronous networks in the presence of adaptive antenna arrays, and proposes two novel access schemes to realize multipacket communication (MPC). Both presented solutions, which rely on the information acquired by each node during the monitoring of the network activity, are suitable for distributed and heterogeneous scenarios, where nodes equipped with different antenna systems can coexist. The first designed scheme, called threshold access MPC (TAMPC), is based on a threshold on the load sustainable by the single-node, while the second protocol, called signal-to-interference ratio (SIR) access MPC (SAMPC), is based on an accurate estimation of the SIR and on the adoption of low density parity check codes. Both protocols, which are designed to be backward compatible with the 802.11 standard, are numerically tested in realistic scenarios. Furthermore, the performance of the two schemes is compared to the theoretical one and to that of the 802.11n extension in a mobile environment

    MAC Protocols for Wireless Mesh Networks with Multi-beam Antennas: A Survey

    Full text link
    Multi-beam antenna technologies have provided lots of promising solutions to many current challenges faced in wireless mesh networks. The antenna can establish several beamformings simultaneously and initiate concurrent transmissions or receptions using multiple beams, thereby increasing the overall throughput of the network transmission. Multi-beam antenna has the ability to increase the spatial reuse, extend the transmission range, improve the transmission reliability, as well as save the power consumption. Traditional Medium Access Control (MAC) protocols for wireless network largely relied on the IEEE 802.11 Distributed Coordination Function(DCF) mechanism, however, IEEE 802.11 DCF cannot take the advantages of these unique capabilities provided by multi-beam antennas. This paper surveys the MAC protocols for wireless mesh networks with multi-beam antennas. The paper first discusses some basic information in designing multi-beam antenna system and MAC protocols, and then presents the main challenges for the MAC protocols in wireless mesh networks compared with the traditional MAC protocols. A qualitative comparison of the existing MAC protocols is provided to highlight their novel features, which provides a reference for designing the new MAC protocols. To provide some insights on future research, several open issues of MAC protocols are discussed for wireless mesh networks using multi-beam antennas.Comment: 22 pages, 6 figures, Future of Information and Communication Conference (FICC) 2019, https://doi.org/10.1007/978-3-030-12388-8_

    Cross-layer Design for Wireless Mesh Networks with Advanced Physical and Network Layer Techniques

    Get PDF
    Cross-layer optimization is an essential tool for designing wireless network protocols. We present a cross-layer optimization framework for wireless networks where at each node, various smart antenna techniques such as beam-forming, spatial division multiple access and spatial division multiplexing are employed. These techniques provide interference suppression, capability for simultaneous communication with several nodes and transmission with higher data rates, respectively. By integrating different combinations of these multi-antenna techniques in physical layer with various constraints from MAC and network layers, three Mixed Integer Linear Programming models are presented to minimize the scheduling period. Since these optimization problems are combinatorially complex, the optimal solution is approached by a Column Generation (CG) decomposition method. Our numerical results show that the resulted directive, multiple access and multiplexing gains combined with scheduling, effectively increase both the spatial reuse and the capacity of the links and therefore enhance the achievable system throughput. The introduced cross-layer approach is also extended to consider heterogeneous networks where we present a multi-criteria optimization framework to model the design problem with an objective of jointly minimizing the cost of deployment and the scheduling period. Our results reveal the significant benefits of this joint design method. We also investigate the achievable performance gain that network coding (with opportunistic listening) when combined with Successive Interference Cancellation (SIC) brings to a multi-hop wireless network. We develop a cross-layer formulation in which SIC enables concurrent receptions from multiple transmitters and network coding reduces the transmission time-slot for minimizing the scheduling time. To solve this combinatorially complex non-linear problem, we decompose it to two linear sub-problems; namely opportunistic network coding aware routing, and scheduling sub-problems. Our results affirm our expectation for a remarkable performance improvement when both techniques are jointly used. Further, we develop an optimization model for combining SIC with power control (PC). Our model optimally adjusts the transmission power of nodes to avoid interference on unintended receivers and properly embraces undesired interference through SIC. Therefore, it provides a balance between usage of PC and SIC at the transmitting and receiving sides, respectively. Our results show considerable throughput improvement in dense and heavily loaded networks

    On the Performance Analysis of Underlay Cognitive Radio Systems: A Deployment Perspective

    Get PDF
    We study the performance of a cognitive underlay system (US) that employs a power control mechanism at the secondary transmitter (ST) from a deployment perspective. Existing baseline models considered for performance analysis either assume the knowledge of involved channels at the ST or retrieve this information by means of a band manager or a feedback channel; however, such situations rarely exist in practice. Motivated by this fact, we propose a novel approach that incorporates estimation of the involved channels at the ST in order to characterize the performance of the US in terms of interference power received at the primary receiver and throughput at the secondary receiver (or secondary throughput). Moreover, we apply an outage constraint that captures the impact of imperfect channel knowledge, particularly on the uncertain interference. Besides this, we employ a transmit power constraint at the ST to classify the operation of the US in terms of an interference-limited regime and a power-limited regime. In addition, we characterize the expressions of the uncertain interference and the secondary throughput for the case where the involved channels encounter Nakagami-m fading. Finally, we investigate a fundamental tradeoff between the estimation time and the secondary throughput depicting an optimized performance of the US

    Energy Harvesting Enabled Relaying network: Design System and Performance Analysis

    Get PDF
    The thesis deals with the design of new protocols and the analysis of wireless-powered communications networks’ performance. In order to bring the contribution to the science in field of my topic, this thesis starts with the study of wireless power supply policies, namely the separated power (SP) and harvested power (HP) techniques at the relay node in the full-duplex (FD) decode-and-forward (DF) relaying networks (RNs). In the second emphasis, the thesis deals with the factors degrading the system performance, i.e., channel state information (CSI) and hardware impairments (HWIs) using Hybrid time switching-based and power splitting-based relaying (HTPSR) protocol. Besides that, an optimization problem regarding time switching (TS) and power splitting (PS) ratios are solved in this thesis, where a genetic algorithm was used. In the third emphasis of this thesis, a two-way simultaneous wireless information and power transfer (SWIPT) network is considered to be an important technique, in which two new proposed protocols, namely power time splitting-based two-slot (PTSTW) and power time splitting-based three-slot (PTSTH) are deployed and compared with each other. The throughput performance is analyzed for both developed protocols. The following emphasis is the study of relay selection (RS) schemes. The three optimal RS schemes are proposed to examine the system performance, namely: * Half-duplex (HD) deploying maximal ratio combine (HDMRC), * FD deploying joint decoding (FDJD), * and hybrid FD/HD relaying transmission scheme (HTS). All of them operate in two optimal power supply policies - optimal power under the individual power constraints (OPIPC) and optimal power with energy harvesting ability (OPEHA). The simulation results show that the HTS outperforms HDMRC and FDJD, and OPEHA is better than OPIPC. Finally, Optimal time for transmitting power at source (OTPS) and Optimal time for transmitting power at relay (OTPR) are proposed to optimize the transmit power in a cognitive relaying network (CRN). For performance analysis, the outage probability, the rate-energy trade-off and the average energy efficiency are studied to enhance the successful data transmission.Tato dizertační práce se věnuje návrhu nových protokolů pro bezdrátově napájené komunikační sítě, jejichž efektivita je následně podrobena analýze. V této práci jsou probrány přístupy k bezdrátovému napájení komunikačních zařízení, a sice SP (Separated Power) a HP (Harvested Power), kdy energie je získána z okolí. Tyto techniky jsou zkoumány z pohledu tzv. relay uzlu R (Relay node) v plně duplexních sítích RN (Relaying Networks) pracujících v režimu DF (Decode-and-Forward). Mimoto, jsou v práci rozebrány i faktory snižující výkonnost a efektivitu bezdrátově napájených komunikačních systémů využívajících navržený hybridní protokol HTPSR (Hybrid Time Switching-based and Power Splitting-based Relaying). Pro tyto účely je využita zejména informace o stavu kanálu CSI (Channel State Information), přičemž detekovány a vyhodnoceny jsou i vlivy jednotlivých zařízení HWIs (Hardware Impairments). Pro zmíněný protokol HTPSR je v práci taktéž řešen problém optimalizace poměru mezi intervaly časového přepínání TS (Time Switching) a děleného napájení PS (Power Splitting), kde byl využit genetický algoritmus. Další oblastí, která je v této práci zkoumána, je síť umožňující současný přenos informací i energie pro napájení, pro niž byly v rámci této práce navrženy, nasazeny a vyhodnoceny dva protokoly, a to PTSTW (Power Time Splitting-based Two-slot) a PTSTH (Power Time Splitting-based Three-slot). Následně jsou v dizertaci zkoumány tři navržená schémata, ve kterých může být provozován uzel R a je provedena jejich výkonnostní analýza, konkrétně jde o režim: * poloduplexní využívající techniku kombinování maximálních poměrů HDMRC (Half-duplex Deploying Maximal Ratio Combine), * plně duplexní využívající sdružené dekódování FDJD (Full-duplex Deploying Joint Decoding), * a hybridní kombinující oba výše zmíněné způsoby v režimu HTS (Hybrid Transmission Scheme). Všechna tato tři schémata jsou provozována v optimalizovaných režimech provozu, přičemž v práci jsou rozebrány dva – optimální napájení s individuálními limity OPIPC (Optimal Power Under the Individual Power Constraints) a optimální napájení s možností využití získávání energie OPEHA (Optimal Power with Energy Harvesting Ability). Z následných simulací pak bylo zjištěno, že HTS svou efektivitou předčí jak HDMRC, tak FDJD a že režim OPEHA je výhodnější než režim OPIPC. Posledním přínosem této práce jsou dva navržené způsoby určení časových poměrů OTPS (Optimal Time for transmitting Power at Source) a OTPR (Optimal Time for transmitting Power at Relay) s cílem optimalizovat přenos energie v CR (Cognitive Relaying) sítích. Rovněž byly pečlivě zkoumány výkonnostní parametry jako pravděpodobnost výpadku, poměr mezi přenosovou rychlostí systému a dodanou energií a průměrná efektivita systému při přenosu energie, a to za účelem zlepšení vlastností datových přenosů.440 - Katedra telekomunikační technikyvyhově

    Mobile Ad Hoc Networks

    Get PDF
    Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

    Pairing-based cryptosystems and key agreement protocols.

    Get PDF
    For a long time, pairings on elliptic curves have been considered to be destructive in elliptic curve cryptography. Only recently after some pioneering works, particularly the well-known Boneh-Franklin identity-based encryption (IBE), pairings have quickly become an important tool to construct novel cryptographic schemes. In this thesis, several new cryptographic schemes with pairings are proposed, which are both efficient and secure with respect to a properly defined security model, and some relevant previous schemes are revisited. IBE provides a public key encryption mechanism where a public key can be an arbitrary string such as an entity identifier and unwieldy certificates are unnecessary. Based on the Sakai-Kasahara key construction, an IBE scheme which is secure in the Boneh-Franklin IBE model is constructed, and two identity-based key encapsulation mechanisms are proposed. These schemes achieve the best efficiency among the existing schemes to date. Recently Al-Riyami and Paterson introduced the certificateless public key encryption (CL-PKE) paradigm, which eliminates the need of certificates and at the same time retains the desirable properties of IBE without the key escrow problem. The security formulation of CL-PKE is revisited and a strong security model for this type of mechanism is defined. Following a heuristic approach, three efficient CL-PKE schemes which are secure in the defined strong security model are proposed. Identity-based two-party key agreement protocols from pairings are also investigated. The Bellare-Rogaway key agreement model is enhanced and within the model several previously unproven protocols in the literature are formally analysed. In considering that the user identity may be sensitive information in many environments, an identity-based key agreement protocol with unilateral identity privacy is proposed

    Mobile Ad Hoc Networks

    Get PDF
    Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms
    corecore