NLOS UV communication systems using spectral amplitude coding

Noshad, Mohammad; Brandt-Pearce, Maïté

doi:10.1109/glocomw.2011.6162574

Cited by 12 publications

(4 citation statements)

References 14 publications

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“…6 for a dispersive FSO link. A practical example of a dispersive FSO link is non-line of sight ultraviolet (NLOS-UV) communications [15]. For this FSO link, the channel impulse response is assumed to be Gaussian with broadening factor σ, i.e.…”

Section: Numerical Resultsmentioning

confidence: 99%

Multilevel pulse-position modulation based on balanced incomplete block designs

Noshad

Brandt-Pearce

2012

2012 IEEE Global Communications Conference (GLOBECOM)

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In this paper, two new modulation schemes using multilevel pulse-position modulation (PPM) for application in unipolar optical wireless systems are presented. Balanced incomplete block designs (BIBD) are used for constructing the symbol alphabets. Each symbol is obtained by combining multiple codewords of a BIBD code. In one scheme the symbols have equal energies, and therefore, no threshold is needed to make a decision on the received signal. The other modulation has better performance yet higher complexity. Since cyclic BIBDs are used for constructing the symbols, the transmitters and receivers have simple structures, and can be implemented using shift registers. These schemes can achieve high spectral-efficiencies, and are therefore suitable for systems with bandlimited sources or highly dispersive channels, where intersymbol interference (ISI) has a significant impact on the performance. We also show that using the same receiver structure, the constellation size can be increased by including the complements of the codewords. The performance of the proposed schemes are compared to other modulation schemes for both LED-based non-dispersive and dispersive freespace optical (FSO) systems.Index Terms-Multilevel modulation, pulse position modulation (PPM), balanced incomplete block design (BIBD), free space optical (FSO) systems, spectral-efficiency

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Section: Numerical Resultsmentioning

confidence: 99%

Multilevel pulse-position modulation based on balanced incomplete block designs

Noshad

Brandt-Pearce

2012

2012 IEEE Global Communications Conference (GLOBECOM)

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“…A scattering communication link at ultraviolet frequencies was put forward by Sunstein [1] in 1968. A single scattering channel model for non-line-of-sight (NLOS) was proposed by Luettgen et al [2] in 1991, and became an authoritative cited reference [3][4][5][6] . The experimental performance using this model was studied for pulse-position modulation (PPM) or on-off keying (OOK)modulation on light emitting diode (LED) based test bed [5,7,8] .…”

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confidence: 99%

An ultraviolet laser communication system using frequency-shift keying modulation scheme

Peng

Shi

Guang-hui

et al. 2015

Optoelectron. Lett.

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A communication system based on an ultraviolet (UV) laser at 266 nm is presented to improve the communication distance. The pulse frequency-shift keying (FSK) modulation scheme is studied and improved in order to reduce the bit error rate (BER), and is put into practice on a field programmable gate array (FPGA). The mathematical models of the modulation and demodulation are established. A test platform is set up to measure the energy density and pulse response under different distances and receiver elevation angles. It is shown that the omnibearing communication can be realized, and the bit rate is limited to 12.5 Mbit/s. The BER is estimated to be less than 10 -7 at distance of 300 m in line-of-sight (LOS) communication model and to be less than 10 -6 at distance of 80 m in non-line-of-sight (NLOS) communication model. Ultraviolet (UV) communication has become an interesting alternative for military communications in the last two decades. In the UV band (200-280 nm), because the sunlight is filtered by the ozone layer and the background radiation is low, weak signals can be detected by the receiver. Meanwhile, the UV light can propagate for only several kilometers due to the high atmospheric scattering and absorption, so the hostile forces cannot detect the signal on our part. UV communication becomes an important military application when radio, wire or fiber communication links are unavailable, unreliable or untrustworthy. It has attracted the attention of researchers because of its good secrecy in recent years. A scattering communication link at ultraviolet frequencies was put forward by Sunstein [1] in 1968. A single scattering channel model for non-line-of-sight (NLOS) was proposed by Luettgen et al [2] in 1991, and became an authoritative cited reference [3][4][5][6] . The experimental performance using this model was studied for pulse-position modulation (PPM) or on-off keying (OOK)modulation on light emitting diode (LED) based test bed [5,7,8] . However, the communication distance is restricted to dozens of meters because the light output power of LED is finite.In this paper, a pulse laser is utilized as the UV source to increase the communication distance. The mathematical models of modulation and demodulation are established. The binary frequency-shift keying (2FSK) is applied and improved to adjust the laser device, and a modified quaternary frequency-shift keying (4FSK) is imported for comparison. A statistic bit error rate (BER) is conducted to explain the performance of the communication system. The UV communication system consists of two basic components: the transmitter (Tx) and the receiver (Rx) [9] . In the transmitter, a pulse laser is modulated by a field programmable gate array (FPGA) to carry digital signal generated from a computer. The output UV light is scattered through atmosphere channel to establish a communication link. At the receiver, a photomultiplier tube (PMT) aided by a solar-blind optical filter is employed for light detection, and another FPGA is utilized to demodulate the si...

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“…The results in this chapter have been published in [13], [14] and [15]. This chapter is organized as follows.…”

Section: Communication Systemsmentioning

confidence: 99%

“…13 compares the BER of a CCM-OCDMA system using a (101,25,7)-OOC to that of the coded-MEPPM using a (101,11,2)-OOC and (101,25,6)-BIBD for different number of active users up to 10 users. For both systems, the PAPR is 4 and the constellation size is 101.…”

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Applications of Balanced Incomplete Block Designs to Communication Systems

Iranzad

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Balanced incomplete block design (BIBD) is an area of combinatorial mathematics that was first introduced in 1936 and developed very fast. Because of their unique fixed cross-correlation property, BIBDs have attracted the attention of researchers in communication systems. BIBDs have been used in various areas, such as error control coding, cryptography, code division multiple access networks, key distribution in sensor networks and watermarking. Among different BIBDs, symmetric designs are often used as codes; in order to simplify the signal processing, cyclic structures are of greatest interest.In this dissertation, we introduce new applications of symmetric BIBDs in communication systems, with special emphasis on optical communications, and use them primarily in constructing the symbols of novel M -ary modulation schemes. The first modulation technique introduced is a spectral amplitude encoded scheme that uses BIBDs as the encoding pattern, and is shown to achieve a high bit-rate in non-line-of-sight ultraviolet (NLOS-UV) systems. The other three modulation schemes are based on pulse position modulation technique, and are proposed for application is systems with certain restrictions, such as peak-power limited systems. Because of the structure of the symbols in these modulation schemes, the symbols are susceptible to interference between adjacent time-chips, and the error probability increases in dispersive channels. We introduce a technique to decrease the interference effect on these three modulation schemes by interleaving the transmitted pulses at the transmitter and de-interleaving them at the receiver.We then study the application of the new modulation schemes to visible light communication (VLC) systems. VLC is an appealing technology that is proposed for wireless indoor networking. Using this technique internet access can be provided by LED-based lighting system. Due to the integration of the illumination system with the communication system, it is crucial that the modulation techniques support lighting features. Dimming and low-fluctuations are the most challenging features to be supported by a communication system. We show that the proposed modulation techniques are able to provide a wide range of dimming levels and have a low fluctuation effect. We also present two techniques that enable VLC systems to provide simultaneous high-speed network access for multiple users.First and foremost, I would like to express my sincere gratitude towards my supervisor, Professor Maïté Brandt-Pearce, for her support, encouragement, and patience during my PhD career.

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NLOS UV communication systems using spectral amplitude coding

Cited by 12 publications

References 14 publications

Multilevel pulse-position modulation based on balanced incomplete block designs

Multilevel pulse-position modulation based on balanced incomplete block designs

An ultraviolet laser communication system using frequency-shift keying modulation scheme

Applications of Balanced Incomplete Block Designs to Communication Systems

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