Data Transmission Format Research Articles

Wireless Networking for Monitoring and Control System of a Steel Plant

The wired networks have been traditionally used in monitoring and control of industrial plants. The trend is changing with the fast development of wireless technologies, which are challenging the wired technologies. This paper concerns with the issues related to the design of wireless network for monitoring and control of an industrial plant. In particular, measurements were conducted inside a steel plant to characterize the radio propagation environment and make a choice on a suitable technology. The channel impulse response (CIR) is measured at 1.8 GHz and from the collected data a number of link parameters are extracted. The measured CIR is also used to simulate performance of a number of data transmission formats. Finally, a number of wireless technologies are evaluated to determine their suitability to the characterized environment.

Study of new modulation data-transmission formats for dispersion-controlled high-bit-rate fibreoptic communication lines

The results of simulation of the propagation of optical signals in a multichannel high-bit-rate fibreoptic communication line with a combined scheme for amplifying optical signals based on new modulation data-transmission formats are presented. A comparative characteristic of formats with the amplitude and phase modulations of the electromagnetic-wave carrier is presented. The results of numerical simulation show that phase-modulation formats have a considerable advantage over amplitude formats. The use of phase-modulation formats leads to an increase in the maximum range of high-quality communications by a factor of three on average compared to amplitude-modulation formats. It is shown that optimal propagation regimes both in the case of amplitude-modulation and phase-modulation formats are realised for the normal (negative) group-velocity dispersion. However, the dispersion value for amplitude-modulation formats proves to be considerably greater than for phase-modulation formats.

Iterative Design and Detection of a DFE in the Frequency Domain

Error-propagation phenomena and computational complexity of the filters' design are important drawbacks of existing decision-feedback equalizers (DFE) for dispersive channels. In this paper, we propose a new iterative block DFE (IBDFE) which operates iteratively on blocks of the received signal. Indeed, a suitable data-transmission format must be used to allow an efficient implementation of the equalizer in the frequency domain, by means of the discrete Fourier transform. Two design methods are considered. In the first method, hard detected data are used as input of the feedback, and filters are designed according to the correlation between detected and transmitted data. In the second method, the feedback signal is directly designed from soft detection of the equalized signal at the previous iteration. Estimators of the parameters involved in the IBDFE design are also derived. From performance simulations on a wireless dispersive fading channel, we observed that the IBDFE outperforms existing DFEs. Moreover, the IBDFE exhibits a reduction of the computational complexity when compared against existing schemes, both in signal processing and in filter design.

Frequency-domain interference cancellation and nonlinear equalization for CDMA systems

In wireless broadband communications using code division multiple access (CDMA), interference cancellation (IC) techniques have been proposed to reduce multiuser access interference (MAI); however, their performance is limited by complexity constraints that still favor the use of rake receivers. In this paper, we propose an IC architecture that makes use of a block decision feedback equalizer (DFE) to remove intersymbol interference (ISI) and whose overall complexity is much lower than equivalent (in terms of performance) existing structures. In fact, by making use of a particular block data transmission format, all filters are implemented in the frequency domain (FD), and in particular, the DFE is iteratively designed according to the reliability of the detected data in the previous iteration. Due to the strong interaction of the FD-IC and the block DFE, error propagation in the receiver is reduced by simply interleaving (INT) chips before transmission. Simulations performed for an uplink communication on a wireless multipath channel show that the combination of FD-IC, block DFE, and chip INT provides an efficient solution with good performance for CDMA systems in dispersive channels.

Optical time division multiplexing: systems and networks

The recent advances in optical time division multiplexed (OTDM) systems and components research show the technique to be highly suited to the generation and transmission of high capacity data on a single optical carrier. This approach uses a single wavelength to carry capacities of at least 40 Gb/s. Such systems are based on a clock frequency and tributary data rates which are easily accessible using electronic components. Short optical pulses are used in a return-to-zero data transmission format with temporal interleaving to map a number of optical data channels into a single electronic clock cycle. It is an approach that can be used to achieve extremely high data-rate bit interleaved systems. This article summarizes the developments in this field and outlines a possible methodology to evolve transport networks to encompass the potential that both WDM and OTDM have to offer. >

Power spectral analysis of skewed data transmission scheme

The spectral characteristics of a new data transmission scheme are obtained. These are compared with other known data transmission formats such as the polar, bipolar, and Manchester signalling formats. It is shown that the new scheme has favourable spectral characteristics. Performance is also obtained when the scheme is applied to existing signalling formats.

Interfacing the ARIA II Automated Radioimmunoassay Analyzer with a Desktop Computer

A technique for developing an electronic interface between the Becton Dickinson ARIA II and a desktop computer is presented. The interface, consisting of both hardware and software components, was created for the BASIC language Hewlett-Packard 9845T, although the concepts are applicable to other computers. Hardware considerations include the proper pin-to-pin wiring configuration and relevant data transmission rates and formats. A transfer-timeout interrupt software routine captures the ARIA II data, and string array manipulation selectively prints test results.