Amplitude Pulse Position Modulation Research Articles

大气激光通信中的多层空间脉冲位置幅度调制

大气激光通信中的多层空间脉冲位置幅度调制

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

Underwater wireless optical MIMO system with spatial modulation and adaptive power allocation

In this paper, we investigate the performance of underwater wireless optical multiple-input multiple-output communication system combining spatial modulation (SM-UOMIMO) with flag dual amplitude pulse position modulation (FDAPPM). Channel impulse response for coastal and harbor ocean water links are obtained by Monte Carlo (MC) simulation. Moreover, we obtain the closed-form and upper bound average bit error rate (BER) expressions for receiver diversity including optical combining, equal gain combining and selected combining. And a novel adaptive power allocation algorithm (PAA) is proposed to minimize the average BER of SM-UOMIMO system. Our numeric results indicate an excellent match between the analytical results and numerical simulations, which confirms the accuracy of our derived expressions. Furthermore, the results show that adaptive PAA outperforms conventional fixed factor PAA and equal PAA obviously. Multiple-input single-output system with adaptive PAA obtains even better BER performance than MIMO one, at the same time reducing receiver complexity effectively.

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.

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.

Performance of Multi Pulse Position Amplitude Modulation for TH IR-UWB Communication Systems

Performance of Multi Pulse Position Amplitude Modulation for TH IR-UWB Communication Systems

Performance of Multi Pulse Position Amplitude Modulation for TH IR-UWB Communication Systems

The multi pulse position amplitude modulation scheme for time-hopping multiple access impulse radio ultrawideband communication systems has been presented in this paper. Multi pulse position amplitude modulation is a hybrid modulation technique, which combines multi pulse position modulation and pulse amplitude modulation. It is shown that multi pulse position amplitude modulation significantly outperforms pulse position modulation with respect to bandwidth efficiency. The multi pulse position amplitude modulation error probability over IEEE 802.15.3a multipath fading channels in multiuser environment is derived. The system analysis shows that the proper selection of modulation parameters can improve the system performance at the cost of hardware complexity (and vice versa).

光通信中双幅度脉冲位置调制的功率谱分析

光通信中双幅度脉冲位置调制的功率谱分析

光通信中双幅度脉冲位置调制的功率谱分析

光通信中双幅度脉冲位置调制的功率谱分析

光通信中双幅度脉冲位置调制的功率谱分析

光通信中双幅度脉冲位置调制的功率谱分析

Cramer–Rao bounds for channel estimation in UWB impulse radio

This paper addresses the Cramer–Rao bound (CRB) calculation for channel parameter estimation in impulse radio ultra-wide band systems. We consider a time-hopping code scheme with binary pulse position and pulse amplitude modulation formats. We first derive in closed-form the (resp. modified) CRB for the multipath channel parameters in the data-aided (resp. non-data-aided) context. Unlike existing methods, the calculations are derived taking into account the overlapping between signal echoes due to multipaths. We illustrate the benefit of taking into account the overlapping assumption on realistic channel propagation environment. Simulations show that the CRB using the non-overlapping assumption clearly overestimate the performance.

A New Distance Notion for PPAM Space--Time Trellis Codes for UWB MIMO Communications

We introduce a new distance notion and develop novel design criteria for optimal MN-ary pulse position amplitude modulation (PPAM) space-time trellis codes (STTC) for ultrawideband multiple-input multiple-output systems for slow and fast fading at both low and high SNR. Simulation results of the 2,2-ary PPAM STTC, constructed through set partitioning, confirm significant reduction in bit error rate.

Pulse Position Amplitude Modulation for Time-Hopping Multiple-Access UWB Communications

In this letter, we propose a new modulation scheme called pulse position amplitude modulation (PPAM) for ultra-wideband (UWB) communication systems. PPAM combines pulse position modulation and pulse amplitude modulation to provide good system performance and low computational complexity. The channel capacity of PPAM is determined for a time-hopping multiple-access UWB communication system. The error probability and performance bounds are derived for a multiuser environment.