Digital Radio Mondiale Research Articles

Accuracy Analysis of the Millington's Prediction Method in the Medium Waveband

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Millington's field strength prediction method is analyzed under different simulation conditions on the basis of the results of a medium waveband (MW or medium wave band extends from 530 to 1600 kHz) digital radio mondiale (DRM) measurement campaign. Millington technique applies the reciprocity condition by simply averaging the forward and reverse field strength values. This simplified approach could be a source of field strength prediction error in the MW planning tools. Critical path features for the fulfillment of the reciprocity condition are identified and their influence on predicted values is stated. Reciprocity effect on the predictions error is evaluated by means of the difference between digital medium wave field strength measured values of certain critical selected paths, and the corresponding Millington's method predicted ones. It has been found that the prediction error can be as high as 15 dB when comparing Millington's method results and measurements but the simple reciprocity approach made by Millington procedure is not the most remarkable source of error. </para>

Reduction of Non-Orthogonal Interference in OFDM Receivers by Optimized Windowing

For conventional orthogonal frequencydivision multiplexing (OFDM) systems, the guard interval is disregarded in the receiver and rectangular shaped windows are used implicitly due to the discrete Fourier transform (DFT). We consider a Nyquistshaped window in the receiver, so that the transmit signal does not need to be modified, and optimize the window shape in order to suppress interference from non-orthogonal single carrier interferer signals. For the window coefficients, a closed form solution is derived. This type of interference occurs for example in OFDM radio systems like Digital Radio Mondiale (DRM) that are operating in low frequency bands. (Disturbance is given for instance by harmonics of switched-mode power supplies.) Further for multiple interferers, the receiver with optimized window outperforms the conventional receiver.

Medium Wave Digital Radio Mondiale (DRM) Field Strength Time Variation in Different Reception Environments

This paper examines the temporal variability in fixed reception of the ground-wave propagated DRM (Digital Radio Mondiale) signal. This field strength analysis in the medium wave band has been performed using the first Spanish DRM field trial. Several fixed reception points located along radial routes provided the field strength sample distributions in rural and suburban areas. Additionally a second measurement campaign was carried out in several dense and open areas of downtown Madrid. The maximum likelihood estimations and logarithmic functions were used to analyse the fit of the experimental data with theoretical statistical distributions. A deep analysis of the most important parameters of the distribution has been carried out in order to characterize the field strength behavior in the different reception situations. It has been taken into account the influence of environment, measurement time interval, distance to the transmitter and the presence of critical reception impairments. The most remarkable result of this study has shown that the time variability of the ground-wave medium wave DRM channel is well approximated by a Log Normal and also by a Nakagami process. The Log Normal distribution is preferred as it is the one considered by the analog medium wave broadcasts for the ground-wave propagation case

Europe Dithers Over Digital Radio

Because of unspecified technical glitches, Digital Radio Mondiale (DRM) technology failed to take off when it was first introduced in 2005. As the 2006 holiday season draws near, DRM advocates are once again optimistic about the prospects of the technology. DRM technology was originally developed as a non-proprietary digital technology for terrestrial broadcasting at frequencies of 30 megahertz and below, to supplement the satellite transmission technologies already in place. Although DRM's sound quality wont match that of true hi-fi, listeners will appreciate having shortwave and AM stations coming in at near-FM quality. More importantly, listeners will be able to get many more stations than before, and if they purchase a well-equipped radio, they will have user-friendly ways to identify and select programs of interest

Performance evaluation of low density parity check codes for Digital Radio Mondiale (DRM) system

In Digital Radio Mondiale (DRM) system, achieving good audio quality becomes a challenge due to its limited band-width of 9 or 10kHz and the very bad fading channels. Therefore, DRM needs highly efficient channel coding schemes. This paper, proposes the schemes which use the Low-Density Parity-Check (LDPC) coded Bit-Interleaved Coded Modulation (BICM) schemes for the implementation of DRM systems. Simulation results show that the proposed system is more efficient than the Rate Compatible Punctured Convolutional (RCPC) coded DRM system on various broadcast channels, and may be recommended as a coding technology for Digital Amplitude Modulation Broadcasting (DAMB) systems of China.

Ambiguity function analysis of Digital Radio Mondiale signals for HF passive bistatic radar

Presented is an ambiguity function analysis of Digital Radio Mondiale signals in the HF band to demonstrate their suitability for HF passive bistatic radar. The ambiguities and interference floor are studied for different integration times. It is shown that interference floors of −40 dB are achieved with a 5 s integration time and that the ambiguity function properties are virtually independent of broadcast content, resulting in a very useful illuminator of opportunity.

Medium Wave DRM Field Test Results in Urban and Rural Environments

This paper presents the results of the first Spanish field trial carried out to analyze a DRM (Digital Radio Mondiale) system in the medium-wave band. A 4-kW average power omni directional ground-wave experimental DRM transmission at a frequency of 1359 kHz was surveyed by means of a measurement vehicle for fixed and mobile reception. Several radial routes starting from the transmitter site provided rural and suburban behavior features of the system. Urban reception trials were performed in several dense and open streets of Madrid, within the expected coverage area. Field strength threshold values were determined for the tested transmission configurations and compared with the AM ground-wave ITU model predictions. Reliability versus distance from the transmitter is stated in this paper for different transmission configurations and the causes of dropouts for different reception conditions are explained. This analysis took into account subjective quality features of each configuration, providing practical planning parameter values.

Minimum C/N requirements for DRM reception based on field trials

This paper presents field measurements results of minimum signal to noise ratio required to achieve a threshold BER based on the first medium wave Digital Radio Mondiale (DRM) measurement campaign in Spain. The main goal of these measurements has been to compare the laboratory simulated values recommended by the ITU with field measurements using real transmission and reception systems and real propagation and reception environments.

What exactly is Digital Radio Mondiale?

What exactly is Digital Radio Mondiale?

Digital radio mondiale (drm) digital sound broadcasting in the am bands

The paper describes the new world-wide broadcasting system Digital Radio Mondiale/spl trade/ (DRM/spl trade/) for the long, medium and short wave bands. It is originated by the goal of the consortium members to develop a flexible and efficient audio and data broadcasting standard. Better sound quality, more reliable reception in combination with additional service information make DRM a promising successor to analogue AM. Achieving good audio quality becomes a challenging task due to the limited bandwidth of 9 or 10 kHz, especially in often strongly impaired channels. Many other requirements, which were the basis for the system development, are illustrated. The article gives an overview of the system architecture, including the components for multiplexing, modulation, channel coding and source coding. Important receiver aspects, such as synchronization and channel estimation, are also described.

Wideband receiver for Digital Radio Mondiale

Broadcasting within the traditional AM bands is set to change with the introduction of digital broadcasts. Wideband receiver architectures allow many of the advanced functions of standards such as Digital Radio Mondiale to be implemented and upgraded without changing the hardware. This article describes some of the design issues of wideband receivers and the performance of a practical receiver.

Digital Radio Mondiale: key technical features

Digital Radio Mondiale (DRM) is a system that promises to reinvigorate the use of the broadcasting bands below 30 MHz. It offers a dramatic improvement in audio quality, not only improving the audio bandwidth and signal-to-noise ratio, but also countering the effects of selective fading and audible interference from other stations. It is also designed to support various features that will make receiver operation more user-friendly. This article describes the basic &apos;mechanics&apos; of DRM and its features, which include station identification, alternative frequency lists and support for time-varying frequency schedules-of particular importance in HF broadcasting.

Performance analysis of punctured convolutional codes and turbo-codes

Digital radio transmission techniques offer the prospect of improved reception compared with analogue signals and are being introduced for radio broadcasting in the short-wave bands. The coding scheme adopted plays an important part in achieving a high quality in the presence of noise and fading, which can be particularly severe for Digital Radio Mondiale (DRM) receivers. This paper compares the performance of turbo-codes and punctured convolutional codes over the radio broadcast transmission channels proposed in ITU-R Circular Letter 10/LCCE/39. The results show that the bit error ratio for binary communication over both additive white Gaussian noise (AWGN) and Rayleigh fading channels is low for turbo-codes in comparison with that for punctured convolutional codes having the same code rate. This result holds over a wide range of bit energy to noise power ratios. The results, which are evaluated in terms of the efficiency for Gaussian and Rayleigh fading channels, show that system efficiency increases with decreasing code rate.