Differential Amplitude Pulse-Position Modulation for Indoor Wireless Optical Communications

Abstract

<p>We propose a novel differential amplitude pulse-position modulation (DAPPM) for indoor optical wireless communications. DAPPM yields advantages over PPM, DPPM, and DH-PIM<math alttext="$_alpha$"> <mrow> <msub> <mi></mi> <mi>&alpha;</mi> </msub> </mrow> </math> in terms of bandwidth requirements, capacity, and peak-to-average power ratio (PAPR). The performance of a DAPPM system with an unequalized receiver is examined over nondispersive and dispersive channels. DAPPM can provide better bandwidth and/or power efficiency than PAM, PPM, DPPM, and DH-PIM<math alttext="$_alpha$"> <mrow> <msub> <mi></mi> <mi>&alpha;</mi> </msub> </mrow> </math> depending on the number of amplitude levels <math alttext="$A$"> <mi>A</mi> </math> and the maximum length <math alttext="$L$"> <mi>L</mi> </math> of a symbol. We also show that, given the same maximum length, DAPPM has better bandwidth efficiency but requires about <math alttext="$1un{dB}$"> <mrow> <mn>1</mn><mi>&thinsp;</mi><mtext>dB</mtext> </mrow> </math> and <math alttext="$1.5un{dB}$"> <mrow> <mn>1.5</mn><mi>&thinsp;</mi><mtext>dB</mtext> </mrow> </math> more power than PPM and DPPM, respectively, at high bit rates over a dispersive channel. Conversely, DAPPM requires less power than DH-PIM<math alttext="$_2$"> <mrow> <msub> <mi></mi> <mn>2</mn> </msub> </mrow> </math>. When the number of bits per symbol is the same, PAM requires more power, and DH-PIM<math alttext="$_2$"> <mrow> <msub> <mi></mi> <mn>2</mn> </msub> </mrow> </math> less power, than DAPPM. Finally, it is shown that the performance of DAPPM can be improved with MLSD, chip-rate DFE, and multichip-rate DFE.</p

A synopsis of modulation techniques for wireless infrared communication

“…This signalling scheme was proposed recently by Sethakaset and Gulliver [17]. DAPPM has advantages over other modulation schemes including PPM, DPPM and dual header pulse position modulation (discussed in section 2.5) in terms of bandwidth requirements, capacity, and peak-to-average power ratio (PAPR) [17].…”

“…DAPPM has advantages over other modulation schemes including PPM, DPPM and dual header pulse position modulation (discussed in section 2.5) in terms of bandwidth requirements, capacity, and peak-to-average power ratio (PAPR) [17]. The DAPPM is a combination of DPPM and pulse amplitude modulation (PAM).…”

“…When compared with similar modulation techniques, a well designed DAPPM will require the least bandwidth. Considering independent and identically distributed symbols, the slot error rate of an DAPPM can be obtained as [17]:…”

Convolutional coded dual header pulse interval modulation for line of sight photonic wireless links

“…In fact the 3 dB bandwidth of a channel can be less than 30.4 MHz, limiting the unequalized bit rate to few Mbps [2,12]. Different modulation techniques have been suggested and investigated for a number of applications; among them are on-off keying (OOK), PPM [13], differential PPM (DPPM) [14], digital pulse interval modulation (DPIM) [15], DH-PIM [16] and differential amplitude pulse-position modulation (DAPPM) [17]. OOK is the most basic and widely 3 investigated, offering a high bandwidth efficiency at the cost of a low power efficiency.…”

“…In terms of transmission capacity and bandwidth, the DH-PIM offers the best choice compared to the PPM and DPIM at the cost of a more complex symbol header structure and higher power requirement for a given bit error rate (BER) performance [16]. DAPPM is a combination of DPPM and pulse amplitude modulation (PAM), offering advantages over PPM, DPPM and DH-PIM in terms of bandwidth requirements, transmission capacity, and the peak-toaverage power ratio [17].…”