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Conference on Free-Space Laser Communications IV

作者： Yu, M Li, J Ricklin, J Lehigh Univ Bethlehem PA 18015 USA

ISBN: (纸本)0819454885

Atmospheric turbulence is known as the major channel impairment for outdoor long-distance free space optical communication. This paper investigates the performance of high-rate fast-speed Reed-Solomon (RS) codes on log-normal fading FSOC channels. The cases where the channel state information is available and unavailable to the decoder are investigated. The impacts of turbulence strength, temporal correlation, interleaver type and size, as well as performance comparison to turbo codes are reported. Through theoretical analysis and extensive computer simulations, it is shown that impressive coding gain can be achieved for RS codes with very little overhead.

关键词： free space optical communication atmospheric turbulence forward error correction coding Reed-Solomon codes

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THE DEVELOPMENT OF A REAL-TIME WAVEFORM GENERATION AND CAPTURE SYSTEM FOR THE EVALUATION OF MODULATION SCHEMES ON SATELLITE LINKS

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JOURNAL OF THE INSTITUTION OF ELECTRONIC AND RADIO ENGINEERS 1988年第3期58卷 132-138页

作者： STEVENS, RG Satellite Communications Division Royal Signals and Radar Establishment Defford UK

The performance of a satellite communications link is largely defined by the modulation and forward error correction coding scheme used. The ultimate performance is defined by the theoretical Shannon capacity but practical schemes currently fall far short of this limit. To aid the search for improved modulation techniques, a test facility has been developed which will allow potentially advantageous schemes to be evaluated via a satellite link, without the need to develop dedicated modem hardware. The facility has been constructed using a virtual memory computer which handles the generation and capture of analogue waveforms in real time. The generalized design allows the transfer function of a satellite channel with a bandwidth up to 200 kHz to be assessed and so provides for the testing of an arbitrary waveform modulation scheme within this bandwidth limit.

关键词： virtual memory computer capture system modulation Satellite communication systems 200 kHz satellite links Modulation and coding methods forward error correction coding modulation schemes real-time waveform generation transfer function modem Shannon capacity

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Lattice-Based coding to Enhance error Performance of the Hidden Direct Sequence Spread Spectrum

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IETE JOURNAL OF RESEARCH 2021年第6期67卷 754-766页

作者： Sanandaji, Nader Falahati, Abolfazl Iran Univ Sci & Technol IUST Dept Elect Engn Digital Coding & Cryptog Lab DCCL Tehran Iran

A direct sequence spread spectrum is employed together with a lattice coding scheme to enhance physical layer security and efficiency of a wireless communication system against the denial of service attacks, due to the presence of deliberate unwanted interferences. Based on the results, using a direct sequence spread spectrum together with a random "construction A" lattice coding scheme named "DSSS/RCA" can highly improve the error performance compared with similar methods. Regarding a typically large block code length, some constraints on the coding rate and average signal to noise ratio are drawn to guarantee a block error probability which is asymptotically close to zero. Also, the secrecy capacity of DSSS/RCA is investigated and the achievability of perfect secrecy is verified.

关键词： Block error rate Direct sequence spread spectrum forward error correction coding Interference mitigation Lattice coding Secrecy capacity Sphere decoding

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Measurements of radio channels and bit error rate estimation of IEEE802.16 standard in semi-rural environment at three frequencies in the 2-6 GHz frequency band

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IET COMMUNICATIONS 2008年第7期2卷 878-885页

作者： Salous, S. Feeney, S. Khokhar, K. Lewenz, R. Univ Durham Sch Engn Durham England

Simultaneous measurements with 10 MHz bandwidth at 2.5, 3.5 and 5.8 GHz were performed in a rural/semi-rural environment in the UK. The measurements were processed to generate power delay profiles to estimate the root mean square delay spread of the channel. The frequency range of the orthogonal frequency division multiplexing (OFDM) symbol bandwidth that has dropped below a predefined level, termed herein as average fade bandwidth, and the corresponding level crossing are employed to quantify the severity of frequency selectivity. The channel data were used to estimate the bit error rate, for the 256 carrier-OFDM IEEE802.16 standard using a frequency domain channel simulator especially designed for the study. It was found that the performance of quasi-stationary wireless broadband systems depends mainly upon the frequency selectivity and the channel coding rate with 1/2 rate coding giving a superior performance to 3/4 rate coding. Puncturing was found to weaken the capability of forward error correction coding in the presence of series of deep fades in the channel transfer function.

关键词： orthogonal frequency division multiplexing frequency 2.5 GHz mean square error methods frequency 5.8 GHz IEEE802.16 standard power delay profiles wireless channels semi-rural environment channel coding rate forward error correction error correction codes transfer functions radio channel measurements frequency selectivity bandwidth 10 MHz frequency-domain analysis error statistics channel transfer function channel coding forward error correction coding quasistationary wireless broadband system microwave measurement UK OFDM modulation frequency 3.5 GHz WiMax frequency domain channel simulator root mean square delay bit error rate estimation

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Meshed multipath routing with selective forwarding: an efficient strategy in wireless sensor networks

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COMPUTER NETWORKS 2003年第4期43卷 481-497页

作者： De, S Qiao, CM Wu, HY SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA SUNY Buffalo Dept Comp Sci & Engn Buffalo NY 14260 USA Univ SW Louisiana Ctr Adv Comp Studies Lafayette LA 70504 USA

Due to limited functionalities and potentially large number of sensors, existing routing strategies proposed for mobile ad hoc networks are not directly applicable to wireless sensor networks. In this paper, we present a meshed multipath routing (M-MPR) protocol with selective forwarding (SF) of packets and end-to-end forward error correction (FEC) coding. We also describe a meshed multipath searching scheme suitable for sensor networks, which has a reduced signaling overhead and nodal database. Our performance evaluations show that (1) M-MPR achieves a much improved throughput over conventional disjoint multipath routing with comparable power consumption and receiver complexity;(2) to successfully route a message using FEC coding, selective forwarding (SF) consumes much less network resources, such as channel bandwidth and battery power, than packet replication (or limited flooding). (C) 2003 Elsevier B.V. All rights reserved.

关键词： sensor network meshed multipath selective forwarding forward error correction coding energy efficiency performance analysis

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forward error correction and Interleaving Performance for Lasercom Terminals in Fading Channels 34

Forward Error Correction and Interleaving Performance for La...

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Conference on Free-Space Laser Communications XXXIV at SPIE LASE Conference

作者： Roth, Jeffrey M. Rauch, Stephen Reynolds, Brett Schieler, Curt M. Ulmer, Todd G. MIT Lincoln Lab 244 Wood St Lexington MA 02421 USA

ISBN: (纸本)9781510648586;9781510648579

Interleaving is a well-known technique utilizing temporal diversity to mitigate burst errors in a communications link. Interleaving provides robustness at the physical layer of the network stack, at the expense of an increase in latency. An important parameter used in characterizing interleaver performance is the temporal diversity L, defined as the number of statistically independent fade events experienced by an individual codeword. This temporal diversity L characterizes the interleaver's ability to whiten a channel so that forward error correction codes designed to mitigate additive white Gaussian noise function effectively. For large values of L, the interleaver is effectively "infinite", and deeper interleaving produces no additional benefit. As L is decreased, the power penalty grows, and increasingly more average power must be transmitted to ensure error-free decoding at the receiver. Here we investigate interleaver performance in the regime where L is decreasing and the interleaver is not effectively infinite. Our goals are to (1) determine the regime where the interleaver is no longer effectively infinite, and (2) characterize the power penalty as a function of L to understand how the performance degrades as L is reduced. A theoretical model is presented that allows us to investigate interleaver performance in the presence of weak, moderate, and strong turbulence (scintillation indices of 0.2, 0.5, and 1.0, respectively). The model results show a gradual increase in penalty for reduced L for the weak-fading conditions. The moderate and strong fading conditions show similar dependence, with significant penalties over 3 dB developing as L drops below 100, and these penalties grow more rapidly when L drops below 10. We show close agreement to these models with experiments using a fiber-based, optical modem. This optical modem utilizes rate-1/2 coding together with a variable interleaver delay spanning three octaves. The optical data signal is transmitted thro

关键词： Free-space laser communications (lasercom) optical communications interleaving forward error correction coding atmospheric scintillation channel fading

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Performance Simulation and Analysis of M-ary Frequency-Shift Keying with Reed Solomon Encoding, Coherent Demodulation, and Hybrid Soft Decision-Hard Decision Decoding

Performance Simulation and Analysis of <i>M</i>-ary Frequenc...

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MILCOM Military Communications Conference

作者： Spyridis, Konstantinos Robertson, Clark USN Postgrad Sch Grad Sch Engn & Appl Sci Dept Elect & Comp Engn Monterey CA 93943 USA

ISBN: (纸本)9781424481804

All modern communication systems use some form of forward error correction coding. Generally, coding gain is improved when soft decision decoding is used instead of hard decision decoding. While soft decision decoding is a mature technology for convolutional codes, practical soft decision decoding for the commonly used Reed-Solomon (RS) non-binary block code has only recently been developed. Most of the developed SD decoding schemes are either applicable for low to medium code rates with high complexity or for channels that are far from q-ary symmetric. A hybrid hard decision-soft decision (HD/SD) decoding scheme was recently developed for use with bandwidth efficient modulation schemes such as M-ary phase-shift keying (MPSK). Since many communication systems use orthogonal modulation schemes such as M-ary frequency-shift keying (MFSK) for more robust communication links, this paper extends the HD/SD decoding scheme developed for bandwidth efficient modulation to orthogonal modulation. The performance simulation and analysis of MFSK with RS encoding, coherent demodulation, and hybrid HD/SD decoding are presented. The effect of noise other than additive white Gaussian noise, such as pulse-noise interference, is also considered. Furthermore, in our simulations we extend the size of the soft decision reliability information matrix from 2(9) to 2(10) in order to increase the possible decoding lists for hybrid HD/SD decoding.

关键词： forward error correction coding reliability information matrix hard decision decoding soft decision decoding orthogonal signaling

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Performance Simulation and Analysis of M-ary Frequency-Shift Keying with Reed Solomon Encoding, Noncoherent Demodulation, and Hybrid Soft-Decision Hard Decision Decoding

Performance Simulation and Analysis of <i>M</i>-ary Frequenc...

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Military Communications Conference (MILCOM)

作者： Spyridis, Konstantinos Robertson, Clark USN Postgrad Sch Dept Elect & Comp Engn Grad Sch Engn & Appl Sci Monterey CA 93943 USA

ISBN: (纸本)9781467300810

Hybrid hard decision-soft decision (HD SD) decoding is a novel decoding technique for Reed Solomon (RS) codes. HD SD decoding utilizes traditional hard decision RS decoding where the received block is either decoded correctly or a decoding failure exists. In the event of a decoding failure, channel reliability information is used to identify received code symbols with a low probability of being correctly received and to generate new code symbol estimates that are used in the traditional RS decoding algorithm. HD SD RS decoding was developed for use with bandwidth efficient modulation schemes such as M-ary phase-shift keying). Since many communication systems use orthogonal modulation schemes such as M-ary frequency-shift keying (MFSK) for more robust communication links, this paper presents the performance simulation and analysis of MFSK with RS encoding, hybrid HD SD decoding, and noncoherent demodulation. In addition to AWGN, the effects of pulse-noise interference (PNI) are considered. An interesting result is that hybrid HD SD decoding has better performance and error correction capability than either traditional HD decoding or other RS SD techniques that have been examined in the literature, especially when PNI is present.

关键词： forward error correction coding reliability information matrix hard decision decoding soft decision decoding orthogonal signaling noncoherent demodulation

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Experimental evaluation of a parallel blind demodulator combined with a Reed-Solomon decoder in the presence of intersymbol interference

Experimental evaluation of a parallel blind demodulator comb...

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54th IEEE Vehicular Technology Conference (VTC 2001)

作者： Tanada, K Kubo, H Okazaki, A Uraguchi, T Hayashi, S Ishikawa, H Iwase, A Taniguchi, J Mitsubishi Electr Corp Informat Technol R&D Ctr Itami Hyogo 664 Japan

ISBN: (纸本)0780370058

This paper evaluates a parallel blind demodulator combined with a Reed-Solomon (RS) decoder in the presence of intersymbol interference (ISI) by means of hardware experiments. Our target systems are point to multi-point (P-MP) communication systems for business use, of which bit rates in the air are 9.6 kbps. In such narrow frequency band systems, fast time-varying fading is one of serious problems. The implemented parallel blind demodulator employs adaptive maximum-likelihood sequence estimation with per-survivor processing (PSP-MLSE), and the RS code is used for a forward error correction (FEC) code. Finally, experimental results confirm that the parallel blind demodulator combined with the RS decoder achieves excellent BER performance.

关键词： fast time-varying fading beat interference adaptive equalization forward error correction coding

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A Secure and Reliable coding Scheme over Wireless Links in Cyber-Physical Systems

A Secure and Reliable Coding Scheme over Wireless Links in C...

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IEEE International Conference on Communications Workshops

作者： Zechen Zhang Wei Peng Song Liu College of Computer National University of Defense Technology

ISBN: (纸本)9781509015269

Cyber-physical systems connect the physical world and the information world by sensors and actuators. These sensors are usually small embedded systems which have many limitations on wireless communication, computing and storage. This paper proposes a lightweight coding method for secure and reliable transmission over a wireless communication links in cyber-physical systems. The reliability of transmission is provided by forward error correction. And to ensure the confidentiality, we utilize different encryption matrices at each time of coding which are generated by the sequence number of packets. So replay attacks and other cyber threats can be resisted simultaneously. The issues of the prior reliable transmission protocols and secure communication protocols in wireless networks of a cyber-physical system are reduced, such as large protocol overhead, high interaction delay and large computation cost.

关键词： Cyber-physical system forward error correction coding Wireless network Encryption Cyber-physical systems Wireless networks cryptography serial number CARRIER SYSTEM wireless Secure Communication Protocol transport protocols protocol overhead labeling scheme Secure forward error correction coding Confidentiality Sensors

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