Trellis-Coded Multiple-Pulse-Position Modulation for Wireless Infrared Communications

Park, Hyuncheol; Barry, John R.

doi:10.1109/tcomm.2004.826382

Cited by 58 publications

(43 citation statements)

References 16 publications

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“…The union bound on symbol-error probability for multiple PPM with maximum likelihood detection is [7,8] …”

Section: Maximum Likelihood Detectionmentioning

confidence: 99%

“…For example, with a coding level of L ¼ 10, 1024-ary PPM conveys 10 bits of information by a single pulse but the slot duration is 10=1024 narrower than the PCM bit period leading to a prohibitive bandwidth expansion of 1024=10 ¼ 102.4. Multiple PPM [4][5][6][7][8] has been proposed as a technique for offering improved receiver sensitivity over PCM under bandwidth-constrained environments such as the optical wireless channel. In multiple PPM, k-pulses are positioned within a time frame containing S slots leading to S…”

mentioning

confidence: 99%

“…4. Multiple PPM [4][5][6][7][8] has been proposed as a technique for offering improved receiver sensitivity over PCM under bandwidth-constrained environments such as the optical wireless channel. In multiple PPM, k-pulses are positioned within a time frame containing S slots leading to S k À Á symbols per frame.…”

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confidence: 99%

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nk-pulse position modulation for optical wireless communication

Cryan

Sibley

2005

Electron. Lett.

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An original analysis is presented for n k -PPM in which the information is conveyed by the position of k pulses, each within their own frame of n slots, giving n k PPM symbols. Comparisons are made with multiple PPM (MPPM) and it is demonstrated that n k -PPM offers improved orthogonality, a simplified circuit implementation and comparable receiver sensitivity.Introduction: Conventional n-ary pulse position modulation (PPM) has been proposed for optical fibre [1], optical wireless [2] and optical satellite [3] channels, owing to its enhanced sensitivity performance. In this format, L bits (where L is termed the coding level) of pulse code modulation (PCM) are encoded into PPM by positioning a single pulse in one of 2 L time slots. Since a single pulse is conveying L bits of information there is an immediate reduction in average power when compared to PCM. However, this comes at the cost of increased bandwidth consumption. For example, with a coding level of L ¼ 10, 1024-ary PPM conveys 10 bits of information by a single pulse but the slot duration is 10=1024 narrower than the PCM bit period leading to a prohibitive bandwidth expansion of 1024=10 ¼ 102.4. Multiple PPM [4][5][6][7][8] has been proposed as a technique for offering improved receiver sensitivity over PCM under bandwidth-constrained environments such as the optical wireless channel. In multiple PPM, k-pulses are positioned within a time frame containing S slots leading to S

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“…The union bound on symbol-error probability for multiple PPM with maximum likelihood detection is [7,8] …”

Section: Maximum Likelihood Detectionmentioning

confidence: 99%

mentioning

confidence: 99%

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nk-pulse position modulation for optical wireless communication

Cryan

Sibley

2005

Electron. Lett.

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“…However, this is at the cost of significant bandwidth expansion and so alternative, more bandwidth efficient schemes, have been proposed such as multiple PPM [4,5] in which k-pulses are positioned within a time frame containing S -slots leading to S k symbols per frame. Unfortunately, S k is rarely a power of two, which leads to complex encoding and decoding circuitry.…”

Section: Spectral Characterisation Of Thementioning

confidence: 99%

Spectral characterisation of nk pulse position modulation format

Cryan

Menon

2005

Electron. Lett.

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“…Although in OW systems the combination of intensity modulation and direct detection (IM/DD) prevents multipath fading, ISI still constitutes a major system impairment especially at high bit rates in an indoor environment [12][13][14]. In dispersive environment, the maximum likelihood sequence detection (MLSD) technique has been shown to give the optimum result; however, its complexity and delay prohibit its use in many applications [15].…”

Section: Introductionmentioning

confidence: 99%

Bit error performance of diffuse indoor optical wireless channel pulse position modulation system employing artificial neural networks for channel equalisation

Rajbhandari

Ghassemlooy

Angelova

2009

IET Optoelectronics

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Citation: Rajbhandari, Sujan, Ghassemlooy, Zabih and Angelova, Maia (2009) Bit error performance of diffuse indoor optical wireless channel pulse position modulation system employing artificial neural networks for channel equalisation. IET Optoelectronics, 3 (4 Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.)The AbstractThe bit error rate (BER) performance of a pulse position modulation (PPM) scheme for non line-of-sight (LOS) indoor optical links employing channel equalization based on the artificial neural network (ANN) is reported in the paper. Channel equalization is achieved by training a multilayer perceptrons (MLP) ANN. A comparative study of the unequalized "soft" decision decoding and the "hard" decision decoding along with the neural equalized "soft" decision decoding is presented for different bit resolutions for optical channels with different delay spread. We show that the unequalized "hard" decision decoding performs the worst for all values of normalized delayed spread becoming impractical beyond normalized delayed spread of 0.6. However, "soft" decision decoding with/without equalization displays relatively improved performance for all values of the delay spread. The study shows that for a highly diffuse channel the signal-to-noise ratio (SNR) requirement to achieve a BER of 10 -5 for the ANN based equalizer is ~ 10 dB lower compared with the unequalized "soft" decoding for 16-PPM at a data rate of 155 Mbps. Our results indicate that for all range of delay spread, neural network equalization is an effective tool of mitigating the ISI.

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Trellis-Coded Multiple-Pulse-Position Modulation for Wireless Infrared Communications

Cited by 58 publications

References 16 publications

nk-pulse position modulation for optical wireless communication

nk-pulse position modulation for optical wireless communication

Spectral characterisation of nk pulse position modulation format

Bit error performance of diffuse indoor optical wireless channel pulse position modulation system employing artificial neural networks for channel equalisation

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