Time Hopping Pulse Position Modulation Research Articles

A Novel Non-Coherent Q-Ary TH-PPM Transceiver.

Time-hopping pulse position modulation (TH-PPM) stands out as a secure communication due to the pseudo-random characteristics of its time-hopping sequence. However, the conventional TH-PPM transceiver encounters challenges in implementation, particularly in achieving the requisite high precision for synchronization. This paper introduces a novel non-coherent Q-ary TH-PPM transceiver, designed to surpass the Bit error rate (BER) performance of conventional TH-PPM transceivers in scenarios under non-ideal synchronization conditions, which also being straightforward to implement. Firstly, we provide an overview of the conventional TH-PPM transceiver. Secondly, the novel TH-PPM transceiver is introduced. In this context, a novel method for generating the TH-PPM signal is proposed for the transmitter, and a parallel matched-filter algorithm, adapted to the new TH-PPM signal, is presented for the receiver. Subsequently, the investigation delves into an in-depth analysis of BER performance, considering both ideal synchronization conditions and non-ideal synchronization conditions, for both the conventional and the new TH-PPM transceiver. Furthermore, the paper proposes a numerical simulation to validate the theoretical findings. The results demonstrate that the new TH-PPM transceiver outperforms the conventional counterpart by showing better BER performance in scenarios with non-ideal synchronization conditions.

On the Effects of Code Cardinality for TH-PPM Ultra Wideband Systems

This paper demonstrates the effects of code cardinality at transmitter section on bit error rate (BER) performance of time hopping pulse position modulation (TH-PPM) based ultra wideband (UWB) indoor radio communication. In the transmitter, different code cardinality values have been chosen and correspondingly the effects on BER of the system have been investigated. The recently accepted IEEE 802.15.3a model of the UWB channel has been used as the propaga- tion channel model in indoor environment. Results show that the system BER performance is significantly dependent on the code cardinality value of time hopping code. For such higher code cardinality values as in the range from 30 to 50, the BER performance degrades severely. Finally, code cardinality in the range from 10 to 15 has been recommended for TH-PPM system in UWB indoor communications providing better BER performance for the same system data rate requirement

Optimum receiver performance of TH-PPM ultra wideband system in multiple user interference

This paper demonstrates optimum receiver performance in terms of bit error rate (BER) for time hopping pulse position modulation (TH-PPM) ultra wideband (UWB) system in multiple user interference environment for indoor radio communication. Equal gain combining and selective gain combining have been demonstrated in terms of ideal RAKE (ARAKE), selective RAKE (SRAKE) and partial RAKE (PRAKE) receiver performances. The recently accepted IEEE 802.15.3a model of the UWB channel has been used to describe UWB propagation in indoor environment. Two channel scenarios named CM-1 and CM-3 for IEEE 802.15.3a channel model have been investigated principally. Finally, this paper concludes with an approximation of equivalence of number of fingers in SRAKE and PRAKE receivers as well as an indication of SNR gains achievable as the RAKE finger number is increased, espe- cially with multiple user interference (MUI), for a 16.6 Mbit/s UWB system.

Simulation of Interference Effects of UWB Pulse Signal to the GPS Receiver

Ultra-wideband (UWB) pulse signal has an extremely narrow pulse width and wide frequency bandwidth, which overlaps with the operating frequency band of Global Position System (GPS) receivers, posing a potential threat to their performance. In response to this problem, through mathematical analysis and software simulation, the effects of UWB pulse signal under time-hopping-pulse position modulation (TH-PPM) on the performance of GPS receivers were studied. First, the expression and waveform of the UWB pulse signal were analyzed in the time-frequency domain, and it is concluded that the pulse repetition frequency (PRF) mainly affects the discrete spectrum of the UWB signal and the TH code period mainly affects the continuous spectrum. On this basis, the simulation on the power spectral density (PSD) of GPS signal and UWB signal under different pulse parameters was represented, from which a conclusion can be drawn that the PRF is the main factor impacting the PSD of the GPS signal. Furthermore, this paper analyzed the degradation of GPS receiver equivalent carrier-to-noise ratio (C/N0) and C/A code demodulation bit error rate (BER) under UWB interference, which are the crucial evaluating indicators of GPS signal quality. Eventually, we theoretically calculated the minimum interference level of the UWB interference signal to the GPS receiver, providing a theoretical reference for reducing the interference effects of UWB pulse signal on the performance of GPS receivers.

Buried objects detection in heterogeneous environment using UWB systems combined with curve fitting method

A new method is proposed to improve the accuracy of locating buried objects in heterogeneous environments using shifted time pulses with radio impulse ultra wide band (IR-UWB), time-hopping pulse position modulation (TH-BPSK UWB), binary phase shift keying (TH-BPSK UWB) systems combined with the least square curve fitting method (LSCFM). The analytical expression is validated by simulation and the locating errors used to assess the performance of systems. The numerical results indicate that the proposed method has higher accuracy than the conventional ones.

IEEE 802.15.6 WBAN Standard Compliant IR-UWB Time-Hopping PPM Transmitter using SRRC signaling pulse

This paper develops the design of an IEEE 802.15.6 Impulse-Radio (IR) Ultra-Wideband (UWB) transmitter for Wireless Body Area Networks (WBAN) in 180-nm CMOS technology. The transmitter operates at the mandatory data rate of 0.487 Mbps and employs a pulse position controller (PPC) to place the Square Root Raised Cosine (SRRC) pulse for a time-hopping pulse position modulation (TH-PPM) scheme. This transmitter features a novel piece-wise linear approximation (PWLA) approach for generation of SRRC signaling pulse. It is found that the generated PWLA SRRC pulse is fully compliant with the WBAN spectral mask. The proposed PWLA approach has the potential to approximate an arbitrary signaling waveform with a high degree of accuracy and hence should be useful in transceiver realizations.

Covert underwater communication by camouflaging sea piling sounds

To achieve covert underwater acoustic communication, a unique technique of mimicking genuine sea-piling sounds as carrier to convey information is presented. It differs from traditional low signal to noise ratio covert underwater acoustic communication. The communication signal can be detected, but it could not be recognized from the perspective of camouflage to realize covert acoustic communication in the sea. According to the features of sea-piling sounds, a quasi-constant period based pulse position modulation scheme is proposed. First we put each piling sound with identical time interval in time domain and it is moved off the original position with a dedicated time delay which is calculated by modulated information. To make the communication signal akin to the piling sounds, the synchronization header is designed by time hopping pulse position modulation scheme with real piling sounds. At the receiver, basis pursuit algorithm under the theory of compressive sensing is used for channel estimation, and passive phase conjugation technique is used for channel equalization to eliminate the impacts of multipath channel. The feasibility and efficiency of the proposed method are verified by simulation and pool experiment.

Improving ultra wideband (UWB) system by modified random combination of pulses

Ultra-Wideband (UWB) technology uses very narrow pulses of nano-seconds duration to provide very high data rates. The pulses to be used for the UWB are very important and should meet the emission mask regulatory requirements to get good performance when transmitted over the channel. To meet these requirements, a combination of higher order derivatives of Gaussian pulses can be considered to form a combined pulse instead of transmitting them separately. The main aim of this paper is to improve the performance of Ultra Wideband (UWB) multiple access modulation system with a newly Proposed combined pulse, generated using a modified random pulse combining of the first five Gaussian derivative pulses with optimal shaping factors as basic functions. In order to meet the UWB power spectrum regulations, the power spectral utilization of the newly designed pulse is calculated and the bit error rate performance of the pulse position modulation time hopping system using the newly proposed pulse is analyzed in a multi-path channel environment using RAKE receiver. The simulation results carried out in MATLAB software shows that the new proposed combined pulse has higher pulse energy matching the spectral limits of UWB and an improved bit error rate performance as compared to the previous literature results.

Space-Time Diversity Schemes with Blind Channel Estimation for TH-PPM UWB MIMO Communications

—For a time-hopping (TH) pulse position modulation (PPM) based ultra-wideband (UWB) multiantenna system, we propose four coherent space-time (ST) diversity schemes, corresponding to which the correlation template signals with blind channel estimation are also presented. First of all, the issue of channel identifiability based on first-order statistics is addressed, aspired by the singleantenna case [1]. Then, we shed light on that the determination of space-time structure is related to both channel estimation and signal detection. After that, four ST diversity structures are presented to guarantee both the feasibility of blind channel estimation and no multi-antenna interference introduced into signal detection. Finally, substantial simulations show that the proposed ST diversity schemes can significantly outperform the traditional single-antenna system especially for high signal-tonoise ratios whether channel state information is perfect or not.

Research on Multiband Impulse Radio UWB System based on PSWF in Multipath Fading Channel

This paper presents an architecture of Multiband Impulse Radio UWB (MB-IR-UWB) system based on Prolate Spheroidal Wave Function (PSWF) by binary time hopping pulse position modulation (TH-PPM) over multipath fading channel. In order to combat multipath fading, Rake receiver using maximal ratio combining (MRC) is applied to this system, which can successfully capture the unique multipath-rich property and multipath-clustering phenomenon of UWB channels. Through simulation, a comparison of system performance between different types of Rake receiver is analyzed. What’s more, considered multipath delay spread, a data rate estimation of the communicating system is given. Finally we get the conclusion that increasing data rate is best-achieved by increasing the number of subband instead of decreasing the symbol repetition period.

Performance analysis of multiple-input multiple-output relay networks based impulse radio ultra-wideband

In this paper, we study the performance of time hopping pulse position modulation for impulse radio ultra-wideband. We consider relay network applying decode-and-forward protocol. The channels between nodes adopt the IEEE 802.15.4a norms. The bit error rate performance is analyzed considering the effect of interference. Our results show significant improvement due to the diversity gain provided by the relay nodes. However, the performance is limited when multiple access interference MAI is present. To combat the MAI effect and further improve the detection reliability, we propose to use antenna selection at the relay. The relay receiver is assumed to be equipped with multiple antennas, and only the best antenna is selected. This is shown to improve the performance in the presence of MAI and improve the diversity gain.Copyright © 2013 John Wiley & Sons, Ltd.

Performance Analysis of Multiband Impulse Radio UWB Communication System Based on PSWF

To improve the data transmission rate and use spectrum flexibly, a new spectrum allocation method for Multiband Impulse Radio UWB (MB-IR-UWB) is proposed in this paper based on the band-limited and orthogonal characteristics of Prolate Spheroidal Wave Function (PSWF). The system model is built and the bit error rate (BER) formula is deprived by binary time hopping pulse position modulation under additive white Gaussian noise. Moreover, the system performance is analyzed via MATLB simulation. The results indicate that MB-IR-UWB system performance of BER is the same with single-band UWB. However, in the proposed scheme the data can be transmitted in multiple parallel bands, which enjoys much higher transmission rate. In addition, PSWF pulse duration affects the BER performance.

Error Probability Analysis of Time-Hopping Biorthogonal Pulse Position Modulation UWB Systems with a RAKE Receiver over Indoor Multi-Path Fading Channels

This paper presents the error probability analysis of Time-Hopping Biorthogonal Pulse Position Modulation (TH-BPPM) ultra-wideband (UWB) systems with a RAKE receiver over indoor multi-path fading channels. UWB signals suffer from severe multi-path interference when employed in an indoor fading environment. A RAKE receiver can be used to improve the performance of UWB systems. TH-BPPM has attracted much attention in recent years due to its many advantages, such as low probability of error and low complexity. In this paper, the IEEE 802.15.3a indoor channel model is employed to analyze the performance of TH-BPPM UWB systems with different RAKE receivers. The bit error rate (BER) of ARake, PRake, and SRake TH-BPPM UWB systems is derived. The results indicate that ARake has the best performance, SRake is better than PRake when the number of fingers is same.

A fully integrated differential impulse radio transmitter

This paper presents a fully integrated differential impulse radio transmitter for ultra-wideband (UWB) applications. The design features low power dissipation, simple hardware, and a precise differential pulse shape. The transmitter employing the Time Hopping Pulse Position Modulation (THPPM) scheme supports eight simultaneous users' access with 2.5-ns hopping time allocated in a frame time of 20 ns. A differential 5th-derivative Gaussian pulse generator is designed to regulate the pulse shape so as to automatically satisfy the FCC spectrum mask. The transmitter in a 1.8-V 0.18-µm CMOS process is realized in an IC area of 629 µm × 797 µm for its all digital circuit design. The measured Gaussian pulse train shows the random property and the measured 5th-derivative Gaussian pulse has a peak-to-peak amplitude of 154 mV and a pulse width of 820 ps. The average power dissipation of the transmitter is 23 mW.

EXIT chart aided design of near-capacity UWB impulse radio using self-concatenated codes

A near-capacity Time Hopping (TH) Pulse Position Modulation (PPM) based Ultra Wide Band (UWB) Impulse Radio (IR) system is proposed, which invokes iteratively detected Self-Concatenated Convolutional Codes (SeCCC) employing Extrinsic Information Transfer (EXIT) charts. The TH-PPM-UWB-IR-SeCCC system configuration is capable of operating within about 0.9dB of the information-theoretic limits.

Free space optical ultra-wideband communications over atmospheric turbulence channels

A hybrid impulse radio ultra-wideband (IR-UWB) communication system in which UWB pulses are transmitted over long distances through free space optical (FSO) links is proposed. FSO channels are characterized by random fluctuations in the received light intensity mainly due to the atmospheric turbulence. For this reason, theoretical detection error probability analysis is presented for the proposed system for a time-hopping pulse-position modulated (TH-PPM) UWB signal model under weak, moderate and strong turbulence conditions. For the optical system output distributed over radio frequency UWB channels, composite error analysis is also presented. The theoretical derivations are verified via simulation results, which indicate a computationally and spectrally efficient UWB-over-FSO system.

A 3–5 GHz TH-UWB transmitter in 0.18-μm RF CMOS technology

An RF transmitter is proposed for 3–5 GHz time-hopping ultra wideband (TH-UWB) wireless applications. The transmitter consists of a 4-GHz oscillator, a switch with a controllable attenuator and an output matching circuit. Through controlling the low frequency signals with time-hopping pulse position modulation (TH-PPM), the circuit supplies TH-UWB signals and can directly drive an antenna by a transmission line. The transmitter was implemented in a 0.18-μm CMOS technology; the output amplitude is about 65 mV at a 50 ? load from a 1.8-V supply, the return loss (S11) at the output port is less than −10 dB, and the chip size is 0.7 × 0.8 mm2, with a power consumption of 12.3 mW.

Frequency and Time Hopping PPM UWB Multiple Access Communication Scheme

In this paper we propose frequency and time hopping pulse position modulation (FTH-PPM) ultra wideband (UWB) for multiple access communications. We have derived and investigated the bit error probability for the multi-user synchronous transmitter case in multipath channels with Additive White Gaussian Noise (AWGN). Simulation results show that bit error probability performance of FTH-PPM UWB out performs the time hopping pulse position modulated (TH-PPM) UWB system. It also show that multiuser capacity of FTH-PPM UWB system is much better than TH-PPM UWB system.

Parallel Time-Domain Full-Wave Analysis and System-Level Modeling of Ultrawideband Indoor Communication Systems

This paper demonstrates the application of a high-order finite-difference time-domain (FDTD) technique to indoor microwave ultrawideband channel modeling with a two-fold purpose. First, the advantages of both serial and parallel versions of the technique compared to the conventional FDTD are pointed out. It is also shown that the results of this full-wave analysis can be translated from the electromagnetic field level to the system level, to produce simplified, physics-based, site-specific channel models. In particular, the parameters of well-established measurement-based models are determined for a specific indoor site, by means of our electromagnetic simulation. Moreover, the proposed technique is coupled with the Monte-Carlo method to characterize the capacity of a time-hopping pulse position modulation multiple access system. Hence, a connection between the field analysis of a channel and its system-level description is made, establishing the usefulness of this work for performance projections, optimization and compatibility studies of ultrawideband communication schemes and network architectures.

Analytical performance of M-ary time-hopping orthogonal PPM UWB systems under multiple access interference

In this paper, we extend the characteristic-function approach to derive an exact symbol error rate expression for the M-ary time-hopping orthogonal pulse position modulation (THPPM) ultra-wideband (UWB) system under the interference from multiple users. Monte Carlo simulations are then used to validate the analytical solutions. The results are found to be valid even when that the chip width is greater than the pulse duration. Moreover, the analytical results are compared to those found by Gaussian approximation and the Gaussian quadrature rule method. We further show that compared to a binary system, M-ary systems can produce better error rate performance.