Differential Amplitude Pulse-position Modulation Research Articles

Design of Transmitter and Receiver Architectures for Differential Amplitude Pulse-Position Modulation Scheme

Design of Transmitter and Receiver Architectures for Differential Amplitude Pulse-Position Modulation Scheme

Advanced Modulation Scheme for Visible Light Communication

In this paper, an improved version of existing modulation schemes is investigated by inserting Hadamard codes (HC) at the peak slot of each symbol for the Visible Light Communication (VLC) system. The performance of the proposed scheme is analyzed and compared with existing schemes On-Off Keying (OOK), Pulse Position Modulation (PPM), Differential PPM (DPPM), Pulse Amplitude Modulation (PAM), Differential Amplitude PPM (DAPPM) and Differential Pulse Interval Modulation (DPIM). Moreover, the symbol error rate (SER) for kth PAM is derived for ds distances between symbols. The performance in Symbol Error Rate (SER) is improved by introducing the Positive and Negative Amplitudes (PNA) levels with respect to DC-bias. The theoretical and simulation results show that the proposed scheme outperforms the existing schemes in terms of bandwidth, and transmission capacity. Keywords: Hadamard Code Matrix, Modulation, Visible Light Communication

Performance of free space optical communication systems over exponentiated Weibull atmospheric turbulence channel for PPM and its derivatives

In this paper, we have characterized the performance of an intensity modulation/direct detection (IM/DD), free space optical (FSO) communication system in terms of average symbol error rate (SER) over exponentiated Weibull (EW) atmospheric turbulence channel. The system of interest uses on-off keying (OOK) and various pulse position modulation (PPM) schemes. Expressions to assess the SER performance of the modulation techniques under EW atmospheric turbulence channel are derived. Aperture averaging effect on SER performance is also presented. Numerical results are displayed for mentioned modulation techniques and compared graphically under weak, moderate and strong turbulence regime. The simulation results exhibit that for the same peak power, differential amplitude pulse position modulation (DAPPM) provides superior performance than the other modulation schemes considered in this paper.

Adaptive differential amplitude pulse‐position modulation technique for optical wireless communication channels based on fuzzy logic

Optical wireless communication has the potential for extremely high data rates of up to tens of Gb/s. In this study, a hybrid modulation technique named adaptive differential amplitude pulse-position modulation (DAPPM) is proposed to improve channel immunity by utilising optimised modulation to channel. The unit transmission rate, channel capacity, peak-to-average power ratio, bandwidth requirement and power requirement of the DAPPM were determined and compared with other modulation schemes such as on–off key, pulse-amplitude modulation, pulse-position modulation (PPM), differential PPM and multilevel digital pulse interval modulation. The simulation results show that DAPPM gives better bandwidth and power efficiency depending on the number of amplitude level (A) and the maximum length (L) of a symbol. In addition, the fuzzy logic module is developed to assist the adaptation process of DAPPM. Mamdani fuzzy logic method is used in which the decisions made by the system will be approaching to what would be decided by the user in the real world.

Performance Comparison of PIN and APD based FSO Satellite Systems for various Pulse Modulation Schemes in Atmospheric Turbulence

In this paper, the performance of various Pulse Position Modulation (PPM) schemes has been analysed for PIN and APD receivers in the presence of atmospheric turbulence. It is observed that the performance of the APD receiver is always better than that of the PIN receiver as expected. Among the various modulation schemes, the performance of Differential Amplitude PPM (DAPPM) scheme with more number of amplitude levels is better than that of the other schemes for the same single level peak amplitude. Further, the optimum gain of APD receiver does not change substantially for different modulation schemes and turbulent conditions.

On the capacity of indoor optical wireless communications

In this letter, the capacity of an optical wireless communications system in an indoor environment is investigated. We consider various modulation schemes, e.g. pulse-position modulation (L-PPM), differential pulse-position modulation (L-DPPM) and differential amplitude pulse-position modulation (AtimesL-DAPPM). It is shown that L-DPPM provides twice the channel capacity of L-PPM. Moreover, Atimes L-DAPPM has a higher capacity than L-DPPM. The capacity of PPM is degraded more by multipath dispersion than that of DPPM and DAPPM.

Differential Amplitude Pulse-Position Modulation for Indoor Wireless Optical Communications

We propose a novel differential amplitude pulse-position modulation (DAPPM) for indoor optical wireless communications. DAPPM yields advantages over PPM, DPPM, and DH-PIMα 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-PIMα depending on the number of amplitude levels A and the maximum length L of a symbol. We also show that, given the same maximum length, DAPPM has better bandwidth efficiency but requires about 1 dB and 1.5 dB more power than PPM and DPPM, respectively, at high bit rates over a dispersive channel. Conversely, DAPPM requires less power than DH-PIM2. When the number of bits per symbol is the same, PAM requires more power, and DH-PIM2 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.