381 Hits in 3.7 sec

Radio communication via Near Vertical Incidence Skywave propagation: an overview

Ben A. Witvliet, Rosa Ma Alsina-Pagès
2017 Telecommunications Systems  
Both the bigger picture and the important details are given, as well as the relation between them.  ...  Near Vertical Incidence Skywave (NVIS) propagation can be used for radio communication in a large area (200 km radius) without any intermediate man-made infrastructure.  ...  NVIS channel sounding In order to design the modulation and coding system that minimises the Bit Error Rate (BER) and maximizes the throughput of an ionospheric link, a sounding system covering the entire  ... 
doi:10.1007/s11235-017-0287-2 fatcat:5nx7l6kqhnetjktthmazdj3tyq

Recent advances in underwater acoustic communications & networking

Mandar Chitre, Shiraz Shahabudeen, Lee Freitag, Milica Stojanovic
2008 OCEANS 2008  
A series of review papers provide an excellent history of the development of the field until the end of the last decade.  ...  In this paper, we aim to provide an overview of the key developments, both theoretical and applied, in the field in the past two decades.  ...  Throughput the 1990s a number of additional systems were developed and commercialized using both coherent and incoherent modulation.  ... 
doi:10.1109/oceans.2008.5152045 fatcat:wxtgyjz46fhc3a3q3sc2odpfhq

Advances in Underwater Acoustic Networking [chapter]

Tommaso Melodia, Hovannes Kulhandjian, Li-Chung Kuo, Emrecan Demirors
2013 Mobile Ad Hoc Networking  
The objective of this chapter is to provide an overview of the recent advances in underwater acoustic communication and networking.  ...  We briefly describe the typical communication architecture of an underwater network followed by a discussion on the basics on underwater acoustic propagation and the state of the art in acoustic communication  ...  Acknowledgements This chapter is based on material supported by the US National Science Foundation under grants CNS-1055945 and CNS-1126357.  ... 
doi:10.1002/9781118511305.ch23 fatcat:zq22thfjs5aovk3pfllf53mqce

Portable Coastal Observatories

Daniel Frye, Bradford Butman, Mark Johnson, Keith von der Heydt, Steven Lerner
2000 Oceanography  
Use of trade names is for descriptive purposes only and does not imply endorsement by the authors or the US Government.  ...  Additional resources have been provided by the USGS, WHOI's Rinehart Coastal Research Center, the USCG, the MWRA and RDI, Inc.  ...  The radiation pattern of this whip is omni-directional in the horizontal with an approximately 35-degree beam pattern in the vertical, which in the majority of sea conditions is optimal.  ... 
doi:10.5670/oceanog.2000.30 fatcat:ghgqdscvfze6xbk7vultrbuu7q

On Performance of Multicast Delivery with Fixed WiMAX Telemedicine Networks Using Single-Carrier Modulation

Bernard Fong, Guan Yue Hong
2010 Journal of Advances in Information Technology  
In this paper, we analyze the performance of QAM schemes used in a fixed WiMAX system that supports multicast distribution of .real-time traffic for healthcare services by evaluation of system performance  ...  Results are presented by comparing the distribution of video data using QPSK and 16-QAM and bandwidth utilization is calculated for continuous data transmission in remote patient monitoring.  ...  scheme provides optimal compromise between data throughput and cell coverage while provides adequate performance for multicast distribution of video traffic.  ... 
doi:10.4304/jait.1.1.59-65 fatcat:i7cblmti55cw5iiv4cgibbybm4

Cooperative Routing for Energy Efficient Underwater Wireless Sensor Networks

Aqeb Yahya, Saif ul Islam, Maryam Zahid, Ghufran Ahmed, Mohsin Raza, Haris Pervaiz, Fucheng Yang
2019 IEEE Access  
A rigorous evaluation and verification of the proposed scheme with current state-of-the-art yield improved energy efficiency, resulting in extended network lifetime.  ...  THROUGHPUT, DATA RELIABILITY AND DELAY Cooperative Depth Based Routing (CoDBR) scheme is proposed to improve throughput and data reliability [24] . Based on depth information, relays are chosen.  ...  Hence, the sink receives data packets from sensor nodes via acoustic modem and forwards them via radio signals to the base station.  ... 
doi:10.1109/access.2019.2941422 fatcat:z2j5ll6e4zbyppozezgdjwh42a

Underwater acoustic sensor networks: research challenges

Ian F. Akyildiz, Dario Pompili, Tommaso Melodia
2005 Ad hoc networks  
The main challenges for the development of efficient networking solutions posed by the underwater environment are detailed and a cross-layer approach to the integration of all communication functionalities  ...  Different architectures for two-dimensional and three-dimensional underwater sensor networks are discussed, and the characteristics of the underwater channel are detailed.  ...  This work was supported by the Office of Naval Research under contract N00014-02-1-0564.  ... 
doi:10.1016/j.adhoc.2005.01.004 fatcat:wovo66kbunh3thaqu72frivx4m

Protocol design issues in underwater acoustic networks

Paolo Casari, Michele Zorzi
2011 Computer Communications  
These protocols deal with the problems of efficiently scheduling transmissions in a fixed 3D deployment, of optimizing the use of energy by choosing the best mechanisms for topology management, and of  ...  Finally, we briefly discuss the currently available underwater communications hardware (including both commercial and research modems) and comment on which paradigms are currently realizable, with special  ...  of four different approaches: a genie-aided optimal scheme, whereby nodes sleep maximally and know exactly when they should wake up; a scheme where node continuously receive; the STEM scheme; the wakeup  ... 
doi:10.1016/j.comcom.2011.06.008 fatcat:iwsdqf5wjrer7buinegc35gvya

Issues in Underwater Acoustic Sensor Networks

Manjula.R. B, Sunilkumar S. Manvi
2011 International Journal of Computer and Electrical Engineering  
The oceans remain the least explored frontiers on this planet and many oceanic and maritime applications seem relatively slow in exploiting the state-of-the-art info-communication technologies.  ...  Underwater sensor networks (UWSNs) are the enabling technology for wide range of applications like monitoring the strong influences and impact of climate regulation, nutrient production, oil retrieval  ...  Optimal update policies for the sensor reporting rate are needed, to prevent congestion and maximize the network throughput efficiency as well as the transport reliability in bandwidth limited underwater  ... 
doi:10.7763/ijcee.2011.v3.299 fatcat:3ypqy5s4c5cqjaqvnpf7lyx5xm

The state of the art in underwater acoustic telemetry

D.B. Kilfoyle, A.B. Baggeroer
2000 IEEE Journal of Oceanic Engineering  
rate, and channel complexity) of underwater modems is to expand.  ...  Advances in each of these areas as well as perspectives on the future challenges facing them are presented.  ...  Independent use of the resolvable tones in the available bandwidth maximizes data throughput but affords no protection against fading of any one tone.  ... 
doi:10.1109/48.820733 fatcat:fcdvthsjdfexhmm74gtdcmpxy4

The GITEWS ocean bottom sensor packages

O. Boebel, M. Busack, E. R. Flueh, V. Gouretski, H. Rohr, A. Macrander, A. Krabbenhoeft, M. Motz, T. Radtke
2010 Natural Hazards and Earth System Sciences  
This paper presents the technical design of PACT, OBU and the HydroAcoustic Modem (HAM.node) which is used by both systems, along with first results from instrument deployments off Indonesia.  ...  As part of the GITEWS infrastructure, the parallel development of two ocean bottom sensor packages, PACT (Pressure based Acoustically Coupled Tsunameter) and OBU (Ocean Bottom Unit), was initiated.  ...  The GITEWS project (German Indonesian Tsunami Early Warning System) is carried out through a large group of scientists and engineers from the GFZ, German Research Centre for Geosciences (consortium leader  ... 
doi:10.5194/nhess-10-1759-2010 fatcat:s3q674taxnhjvb3xoqlinldhhm

Full Duplex Physical and MAC Layer-Based Underwater Wireless Communication Systems and Protocols: Opportunities, Challenges, and Future Directions

Liu Songzuo, Basit Iqbal, Imran Ullah Khan, Niaz Ahmed, Gang Qiao, Feng Zhou
2021 Journal of Marine Science and Engineering  
Users can send and receive data simultaneously over the FD links, maximizing bandwidth utilization and increasing throughput.  ...  Underwater wireless communication has gained a great deal of attention in the last couple of decades because of its applications in the military, industrial, and monitoring sectors.  ...  The coherence band-width is denoted by ∆ f c , and the rate of signaling I is denoted by W: ∆ f c > W >> f m (1) • As shown below, the channel coherence time is denoted by denoted by ∆t c .  ... 
doi:10.3390/jmse9050468 doaj:3a87114fa30e4f129ebf807d206926c7 fatcat:ucrbnigl2fgapc3i6gjzto7a2u

A Survey on Design and Performance of Higher-Order QAM Constellations [article]

Praveen Kumar Singya, Parvez Shaik, Nagendra Kumar, Vimal Bhatia
2020 arXiv   pre-print
Finally, a comparative study of various QAM constellations is presented which justifies the supremacy of HQAM over other QAM constellations.  ...  With this, it can be claimed that the use of the HQAM in various wireless communication systems and standards can further improve the performance targeted for beyond 5G wireless communication systems.  ...  In [192] , authors analyzed the performance of multi-rate CDMA system and determined the optimal adaptive rate and power allocation strategies to maximize the throughput of the system.  ... 
arXiv:2004.14708v1 fatcat:okupeb57cnaa3kjf3gyzhludde

A Survey on Higher-Order QAM Constellations: Technical Challenges, Recent Advances, and Future Trends

Praveen Kumar Singya, Parvez Shaik, Nagendra Kumar, Vimal Bhatia, Mohamed-Slim Alouini
2021 IEEE Open Journal of the Communications Society  
There have been various solutions to improve the performance, out of them, one of the fundamental solutions over the years is design of optimum modulation schemes.  ...  On the other hand, in cellular communication, power efficiency is a major area of concern for system designers since the mobile phone sensors or Internet of things (IoT) type communications operate on  ...  In [196] , authors analyzed the performance of multi-rate CDMA system and determined the optimal adaptive rate and power allocation strategies to maximize the throughput of the system.  ... 
doi:10.1109/ojcoms.2021.3067384 fatcat:xx3tpsasevbqjg3ej2vktivqdi

Fading Channel Issues in System Engineering

S. Stein
1987 IEEE Journal on Selected Areas in Communications  
The effects of the fading upon data communications are described, along with the techniques of modulation, diversity, coding, and adaptive equalization used in modern modem designs' for operation over  ...  The character of multipath-induced propagational fading is reviewed, along with the interpretations underlying use of the Rayleigh fading model to describe the process statistics.  ...  For orthogonal waveform detection, like noncoherent FSK, phase-coherent combining of branch outputs is still optimal.  ... 
doi:10.1109/jsac.1987.1146536 fatcat:mh2vl5fj5zhr5c5kjbsgep23mu
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