Search

In this paper, an improved frequency offset estimation algorithm is proposed. It can effectively utilize pilot symbols in orthogonal frequency division multiplexing (OFDM) signals based on the Digital Radio Mondiale (DRM) system. In order to reduce the computational difficulty, the difference values of adjacent pilot symbols in the DRM system are sequentially combined into a pilot difference set. The pilot difference set is analyzed by inductive statistics so that the frequency offset estimator has higher calculation efficiency and accuracy. Through the induction statistics of multiple groups of symbols, the contingency of results can be effectively avoided. By comparing the performance of the proposed frequency offset estimator with that of the traditional estimators, the proposed algorithm has higher frequency offset estimation accuracy.

The challenge in the designing of wireless communication system is to get close to the Shannon limit. In this paper, Non Uniform Constellations (NUCs) have been proposed as an alternative to uniform Quadrature Amplitude Modulation (QAM) in Digital Radio Mondiale (DRM) system based on Low Density Parity Check (LDPC). Indeed LDPC has been previously proposed in substitution of convolutionnal code and highlighted a better performance. Also 2D-NUCs performance have been previously highlighted in many broadcasting systems. These constellations shaping is jointly proposed with LDPC as an alternative to QAM + convolutional code in order to increase DRM system capacity. The simulation results show that DRM system based on LDPC/ NUCs outperforms the legacy system 1 dB, 1.18 dB and 1.25 dB SNR gain at a Bit Error Rate (BER) of 10−3respectively for code rates 1/2, 3/5 and 2/3.

Wireless communications are constantly growing with the aim of providing solutions in complex scenarios, such as industrial environments and indoor locations, where impulsive noise sources interfere with the desired signal. Orthogonal frequency-division multiplexing (OFDM) is the most widely used technology, robust against Gaussian noise but sensitive to impulsive noise. To ensure better system performance, it is necessary to the study the impulsive noise and its effects. This work responds to the International Telecommunication Union (ITU), which in ITU-R 214 6/3 question asks for new updated noise measurements to study the systems performance. On the one hand, the study provides novel results of the impulse noise parameters from lifts and, on the other hand, analyses the influence of the impulsive noise originated from lifts at 18 MHz on OFDM digital radio mondiale (DRM) signals. Some radio noise patterns have been measured when lifts are moving up and down. The Gaussian and the impulsive components of these measurements have been computed. The influence of noise patterns in the reception of DRM-OFDM audio signals has been tested with different configuration parameters. The results provided in this report prove that OFDM signals tested are significantly degraded in the vicinity of lifts.

In this paper, an efficient symbol timing offset (STO) and sampling frequency offset (SFO) estimation scheme is proposed in an orthogonal frequency division multiplexing-based digital radio mondiale system using cyclic delay diversity. By using a periodic nature of channel transfer function, cyclic delay and pilot pattern with a maximum channel power are chosen, which aids to enable a robust estimation of STO and SFO against frequency selectivity of the channel. As a performance measure, the mean squared error of the proposed scheme is theoretically derived and is verified through simulations. By simulation results, the proposed estimation scheme is proved to profit from properly selected cyclic delay and pilot pattern, with a superior performance over the conventional estimation scheme.

Successful economic development of the Arctic zone is impossible without creating a continuous information field that covers its entire territory and is available not only at stationary objects, but primarily in moving vehicles - ships, cars, airplanes, etc. This information field must consist from transmission of audio information (broadcasting programs), data (weather maps, ice conditions, etc.), navigation signals, alerts and information about emergencies, and must be reserved from different sources. As a backup system (and in the coming years, the main one) it is advisable to use single-frequency digital broadcasting networks of the Digital Radio Mondiale standard in the low frequency range. This is the most economical system for covering remote areas. For the use of these systems, have all the necessary regulatory framework and standard high-efficiency radio transmitters. The possibility of using standard antenna systems is shown. An example of frequency-territorial planning and a program of preliminary field tests in the experimental zone were developed. It is shown that the entire Arctic region of the Russian Federation, including the Northern Sea Route, can be coverage by a total of 6 transmitters with three frequencies, a total power consumption of 450 kW and annual electricity costs of less than 250,000 US$.

The study of new digital transmission technologies has increasingly gained importance. The implementation of digital radio has not yet been widely accepted, due to several cost factors and regional limitations. This article proposes the study of Digital Radio Mondiale Plus $(\mathbf{DRM +})$ in the Very High Frequency (VHF) band with Low-Density Parity-Check (LDPC) channel codes and Layered Division Multiplexing (LDM) technique. The development of $\mathbf{DRM +}$ was carried out using Software Defined Radio (SDR), which guarantees lower production costs and the ability to develop new packages without having to change the hardware. The results obtained demonstrate that the $\text{DRM} +$ combined with LDPC and LDM techniques guaranteed the system a gain, when compared to the standard system it had a reduction of 1.5 dB in Signal Noise Ration with a Quadrature Phase-Shift Keying (QPSK).

The current state of analogue broadcasting in the Republic of Venezuela is examined and the digital broadcasting standard Digital Radio Mondiale (DRM) promising for future use is selected. The technical basis of designing digital broadcasting networks in a given territory are determined - taking into account climatic features, soil conductivity in various parts of the country and the distribution of maximum levels of atmospheric radio noise. The preferred radio frequencies are determined. It is shown that with a soil conductivity of 25 mS/m, at a distances of up to 65 kilometers from the transmitter, it is preferable to use operating frequencies in the region of 1 MHz. At long distances, it is advisable to move towards lower frequencies. At lower soil conductivity values, in almost all cases, the use of low frequencies provides a larger radius of the service area. Possible scenarios of building a large-clusters network of synchronous single-frequency digital broadcasting of the DRM standard for Venezuela are considered. Clusters sizes, their numbers needed to service a given territory, the main parameters of broadcast transmitting and antenna-feeder devices are determined. The developed example of the topology of a large-clusters single-frequency DRM synchronous network for servicing the entire territory of Venezuela contains three clusters: two clusters with a radius of the transmitter service area of 140 kilometers, consisting of 7 and 8 transmitters, respectively, and one cluster with a radius of the transmitter service area of 90 kilometers, consisting of seven transmitters.

Показано современное состояние цифрового радиовещания в России и в мире. Описаны результаты исследований, проведенных в опытной зоне аналого-цифрового DRM/ЧМ-радиовещания в полосе частот 87,5-108 МГц в Санкт-Петербурге в период с 18 июля 2019 г. по 25 декабря 2020 г. при мощностях аналоговой и цифровой частей передатчика, равных 3000 и 800 Вт соответственно. Приведены результаты оценки электромагнитной совместимости обоих форматов радиовещания. Сформулированы требования, предъявляемые отечественными радиовещателями к системе цифрового радиовещания в диапазоне 87,5-108 МГц, и показано, что аналого-цифровой формат DRM Simulcast соответствует им., The current state of digital radio broadcasting both in Russia and in the world is presented. Digiton Systems LLC carried out a high-power field trial of the DRM system in DRM Simulcast mode by order of the Russian Television and Radio Broadcasting Network (RTRN) in the FM band 87.5-108 MHz in St. Petersburg (Russian Federation) from July 2019 to December 2020. The transmitter was set to radiate at 95.9 MHz FM signal with a transmit power of 3 kW and DRM signal with a transmit power of 800 W simultaneously. The article presents the results of these studies. The results of evaluating the electromagnetic compatibility of FM and DRM broadcasting formats are also described., Электросвязь, Выпуск 4 (17) 2021

Under Doppler shift, multipath effect and noise interference, frequency offset seriously affects the effect of receiving digital radio mondiale (DRM). For the purpose of obtaining good reception performance, frequency offset compensation is essential. According to the transmission frame structure of DRM system, this algorithm availably uses the pilot symbols of fixed positions, makes the difference between them, and combines them into pilot difference set orderly. The integer frequency offset is estimated by inductive reasoning on the pilot difference set. This method makes the estimation of integer frequency offset more efficient and accurate. In order to verify the reliability of the integer frequency offset compensation algorithm, a transmitting system combined with USRP N210 motherboard and 30MHz RF board is proposed, as well as a receiving system which uses a radio with DRM mode to analyze the audio. The audio quality received by the test system is good, and the experimental effect is considerable.

Digital Sound Broadcasting (DSB) has recently attracted attention due to its advantages over analog techniques. Unfortunately, the DSB has not been widely deployed due to inherent problems in reception, receiver cost and limited interactive applications. In this paper, a proposal based on Digital Radio Mondiale Plus (DRM) is presented. The DRM was implemented and tested using GNU Radio Companion (GRC) software with the following techniques: Layered-Division-Multiplexing (LDM) and the Low-Density Parity-Check (LDPC) channel code. These new developments arouse novel approaches for prototyping and testing. The Software-Defined Radio (SDR) provides the flexibility required for the design and development of these new digital communication systems. The results show that the proposed solution provides a asymptotic gain of 10dB with respect to current standard.

In this paper, DRM is applied for simulating coverage prediction in Radio Republik Indonesia (RRI). The proposed method is developed by simulating high frequency propagation from RRI Pro 3 transmitter with VOACAP online software. The simulation is undertaken in some different conditions. The variation of antenna type and transmitter power are observed in the simulation. The time of propagation also discussed to predict the coverage. The result shows that the variation of parameter influences the coverage result of DRM propagation in HF band. Changing the antenna type and time of propagation will make impact in the range of coverage while adding power transmitter gives insignificantly effect to the range of coverage. Keywords—DRM, Prediction Coverage, VOACAP REFERENCES [1] ITU R-REP-BS.2144-2009-PDF-E, “Planning parameters and coverage for Digital Radio Mondiale (DRM) broadcasting at frequencies below 30 MHz”, 2009. [2] M. J. Bradley, “Digital Radio Mondiale: System and Receivers”,Roke Manor Research Ltd, UK, 2003 [3] G. Prieto, I. Pichel, D. Guerra, P. Angueira, J.M. Matias, J.L. Ordiales, A. Arrinda, “Digital Radio Mondiale: Broadcasting and Reception”, IEEE Press, 2004. [4] DRM Features, available under http://www.drm.org [5] “Digital Radio Mondiale (DRM); System Specification,” European Telecommunication Standards Institute (ETSI), ETSI TS 101980, 2001. [6] D. Setiawan, “Alokasi Frekuensi, Kebijakan dan Perencanaan Spektrum Indonesia”, Departemen Komunikasi dan Informatika, 2010. [7] P.A Bradley, Th Dambold, P.Suessmann, “Propagation model for HF Radio Service Planning”, HF Radio Systems and Techniques, Conference Publication No 474 0 IEE, 2000. [8] J.J. Carr, “Practical Antenna Handbook 4th Edition”, McGraw Hill, 1990. [9] J.M Matias et al, “DRM (Digital Radio Mondiale) Local Coverage Tests Using the 26 Mhz Broadcasting Band”, IEEE Transactions on Broadcasting, Vol. 53, No. 1, August 2007. [10] C. A. Balanis, “Antenna Theory Analysis and Design”, 2nd ed, John Wiley & Sons, 2005. [11] Keputusan Direktorat Jendral Pos dan Telekomunikasi Nomor 85/DIRJEN/1999, “Spesifikasi Teknis Perangkat Telekomunikasi, Persyaratan Teknis Perangkat Radio Siaran”, Jakarta, 1999.

This paper is about the development of Digital Radio Mondiale (DRM) App. It describes overall technology and development motivation that may enable us to overcome the limitation of 1:1 Bluetooth technology. It introduces the DRM compression and modulation, background technology of DRM transmitter and receiver, requirements for DRM signal creation, DRM App configuration, additional tools used for field test, the field test results, and future application of DRM.

This study discussed the problem of target detection for digital radio mondiale (DRM)-based passive bistatic radar (PBR). In the surveillance signal, the power of zero Doppler contribution (ZDC) is stronger than the echoes of weak targets. These targets can hardly be shown in the range-Doppler map of classical cross-ambiguity function (CAF). The clutter should be removed before using CAF-matched correlator. The authors utilised Doppler channel detector (CHAD) to solve the above problem for DRM-based PBR in this study. It can unify the ZDC rejection and the target detection in one process. Compared to CAF detector, the CHAD had a lower random pedestal for low Doppler frequency shifts. The results of experiment data proved the effectiveness of the CHAD for DRM-based PBR.

With the development of digital broadcasting technologies, Digital Radio Mondiale (DRM) has become one of the most popular digital broadcasting standards in the world. The DRM Multiplex Generator is an important part of the DRM system, which can generate the digital DRM multiplex to the DRM channel encoder. This paper presents a design and implementation of a PC-based DRM multiplex generator, which multiplexes all the DRM services and generates output streams in Multiplex Distribution Interface (MDI) format. The results show that the system can accomplish multiplex and meet requirements of the DRM standard.

The analog transmission using AM (Amplitude Modulation) and FM (Frequency Modulation) techniques is still commonly used due to its simplicity, inexpensiveness, and reliability than the state of the art digital counterparts. The problems with AM/FM modulation are it consumes more bandwidth, quality of transmission is not good and transmission is not secure. Therefore a digital transmission system is required that uses existing protocols and gives advanced features. In this project, the UCERD Pvt Ltd Islamabad has presented a Software Defined Digital Radio Mondiale (SDDRM) broadcasting system that transfers the information securely over a wide geographical area. The system uses configurable Radio Frequency (RF) front-end, High-Performance Computing (HPC) system and simple to utilize programming environment. The SDDRM gives a complete solution for digitizing analog radio bands such as Short-Wave/Medium-Wave/Frequency-Modulation (SW/MW/FM) and other VHF bands. It can be used for both public and industrial transmissions for national, regional and international coverage. The developed SDDRM is a high-quality digital replacement for popular analog radio broadcasting system for the AM and FM/VHF bands. It gives a complete solution for digitizing analog radio bands. The results confirms that the SDDRM transfers 64 audio channels consecutively over a single frequency band without compromising quality of signals.

It is becoming more and more popular to support multiple radio broadcasting standards, such as Frequency Modulation (FM) and Digital Radio Mondiale for Amplitude Modulation (DRM30), on one channelization system for content and metadata indexing applications. However, existing works mainly focus on supporting only one standard, because different standards usually have different channel characteristics in term of bandwidth and carrier location. This paper presents a flexible and resource-efficient architecture that can simultaneously channelize the entire FM and DRM30 bands. In particular, a coarse/finergrained division based approach is proposed to implement the multi-standard channelization. Therefore, the parameters of each output channel, such as center frequency and output sampling rate, can be independently configured at run-time. Finally, the proposed architecture, which consists of one polyphase Discrete Fourier Transform (DFT) filter bank, one tuning unit, and one resampling filter, is implemented in a single field programmable gate array (FPGA). The experiment results indicate that the proposed design can support both FM and DRM30 standards, and requires less FPGA resources than the existing works which can only support one standard.

In order to study the application of digital radio mondiale (DRM) broadcasting system in medical signal transmission, taking sinusoidal signal as an example, the transmission format is designed, and the data transmission function of the system channel is verified and applied to the transmission of medical information. Taking the traditional electrocardiogram signal and magnetic resonance image as examples, the two kinds of medical information are successfully transmitted according to the appropriate transmission format. As the simplest and easiest to deploy communication mode, the system will provide the fastest and timeliest information and emergency communication function for disaster relief and rescue, which is a practical and valuable application.

One of the key issues of Digital Radio Mondiale (DRM) is green broadcasting. For wide area coverage, the use of high-power transmitters is essential. However, the applied transmission technology based on Orthogonal Frequency Division Multiplexing (OFDM) results in non-linearities in the emitted signal, low power efficiency, and high costs of transmitters. Digital predistortion is a promising scheme for power amplifier (PA) linearization. This paper presents an efficient approach to estimate the parameters of a digital predistorter based on adaptive filtering with direct learning architecture (DLA). A well-known algorithm for identifying and tracking the time-varying parameters of an unknown system is the recursive least squares (RLS) method with exponential/directional forgetting. In this paper, the efficiency of both exponential/directional forgetting techniques is investigated for different degrees of PA nonlinearities. On this basis, a new hybrid technique based on statistical properties of the PA input signal is proposed. The evaluation results show that for both scenarios, the statistic-based forgetting technique not only provides better accuracy but also is more robust against high PA nonlinearities.

The Digital Radio Mondiale (DRM) broadcasting standard is the only ITU approved for worldwide application in the frequency range below 30 MHz. The DRM standard provides the use of single-frequency synchronous broadcasting networks. Their application with competent frequency-territorial planning allows to increase the efficiency of the DRM broadcasting networks, as well as to save the frequency resource. The DRM single-frequency synchronous networks construction in general differs from the DVB-T/DVB-T2 synchronous digital television networks or VHF DAB/DAB + digital broadcasting networks construction due in the presence of ionospheric propagation of radio waves. These features are considered in this article. Method for calculating the synchronism zone is proposed. Consideration of possible scenarios for the placement of transmitters showed that the most advantageous can be considered their placement at an angle of 90 degrees. Tests of single frequency DRM radio network in the SW range with original methodology were conducted. Measurement results show that synchronous network gain reached the values up to 6 dB at a wire antenna and up to 11 dB at a whip antenna. When using traditional for broadcasting “day” and “night” frequencies it is possible to provide broadcast quality with high reliability (i.e., 98% audio decoding) within 24 hours.

Modern high-efficiency EER transmitters to comply with the standards for electromagnetic compatibility require very precise matching with the load. The antennas used on board are often electrically short and therefore narrow-banded. Traditional LC-matching in some cases can not provide the required level of SWR. A method for matching electrically short narrow-band antennas with the help of RLC-circuits is proposed. It allows providing the required SWR value of the load not more than 1.05 in the band of the OFDM signal of 10 kHz and not more than 1.1 in the band of 20 kHz. A technique for designing a RLC frequency extension circuit is developed. The carried out analysis of the energy efficiency of the frequency extension circuit showed that if the antenna 3-dB bandwidth exceeds 10 kHz, the losses in the FEC do not exceed 1 dB. The developed method for calculating the frequency extension circuit was tested for Digital Radio Mondiale (DRM) LW broadcasting stations. The possibility matching of existing antennas with a height of 257 meters for the DRM mode with 9/10 kHz signal bandwidth over the entire range of LW is shown. Also, the potential for using Simulcast mode with a dual signal bandwidth is shown: for the upper half of the low-frequency range, with antennas 257 meters high and 378 meters for the lower one.

The Digital Radio Mondiale (DRM) digital radio standard is the only one recommended by the ITU to be used in Short Wave bands. These bands present unique characteristics for the broadcasting, very big coverage areas and long-range transmission. But they suffer of complicated propagation channel with big time variations that make difficult the regular broadcasting operation. In order to evaluate the DRM performance, field trials were made in Brazil by the Brazilian Government. The objective was to evaluate DRM technology for long-range transmission in Short Wave frequencies. In this paper, the results of these field trials are explained. Two frequencies were used during a period of three weeks at different hours of the day. The transmission was made from French Guyana and the reception was tested in Brasilia.

RESUMO Este artigo se volta para a iminente definicao do Sistema Brasileiro de Radio Digital (SBRD), tendo como objeto privilegiado de analise o middleware Ginga, desenvolvido para a TV Digital Interativa Brasileira. Aponta para a importância da pesquisa colaborativa e independente dos cidadaos envolvidos na defesa da Digital Radio Mondiale como padrao para o Radio Digital Brasileiro e argumenta que o surgimento de uma nova gestao dinâmica do espectro torna obsoleto o seu uso exclusivo, regido historicamente por regimes de concessao. Por fim, observa criticamente a mercantilizacao do espectro como o principal obstaculo a transicao do analogico para o digital e afirma a emergencia de um novo paradigma do espectro, abundante, como bem comum tecnologico. Palavras-chave: Televisao Digital; Radio Digital; Middleware Ginga; Espectro; Paradigma. ABSTRACT The article focuses the imminent choice of the Brazilian Digital Radio System (SBRD), taking as a privileged object the analysis of the Ginga middleware, developed for the Interactive Brazilian Digital TV. Pointing to the importance of collaborative and independent research carried out by citizens engaged in defending the Digital Radio Mondiale standard for Brazilian Digital Radio, we argue for an emerging dynamic spectrum management that makes obsolete its historical and exclusive use governed by concessionary regimes. Finally, we observe the commodification of the spectrum as an obstacle affecting the transition from analogue to digital and affirm a new paradigm of the spectrum as abundant and a technological common good. Keywords: Digital Television; Digital Radio; Ginga Middleware; Spectrum; Paradigm.

In digital radio broadcasting systems, long delays are incurred in service start time when tuning to a particular frequency because several synchronization steps, such as symbol timing synchronization, frame synchronization, and carrier frequency offset and sampling frequency offset compensation are necessary. Therefore, the operation of the synchronization blocks causes delays ranging from several hundred milliseconds to a few seconds until the start of the radio service after frequency tuning. Furthermore, if spectrum inversed signals are transmitted in digital radio broadcasting systems, the receivers are unable to decode them, even though most receivers can demodulate the spectral inversed signals in analog radio broadcasting systems. Accordingly, fast synchronization techniques and a method for spectral inversion detection are required in digital radio broadcasting systems that are to replace the analog radio systems. This paper presents a joint detection method of frame, integer carrier frequency offset, and spectrum inversion for DRM Plus digital broadcasting systems. The proposed scheme can detect the frame and determine whether the signal is normal or spectral inversed without any carrier frequency offset and sampling frequency offset compensation, enabling fast frame synchronization. The proposed method shows outstanding performance in environments where symbol timing offsets and sampling frequency offsets exist.

In this paper, we propose a detection method for Digital Radio Mondiale (DRM) Plus suitable for hybrid mode broadcasting which services both DRM Plus and analog FM within the same frequency band. The guard-interval correlation method of Orthogonal Frequency Division Multiplexing (OFDM) is good for DRM Plus signal detection, but the possibility for false alarm increases when FM signal is received. The proposed method includes a reference block in the guard-interval correlation which increases the identification rate of weak DRM Plus signals and decreases the possibility of false alarm when analog FM is received. The performance of the proposed method is verified through simulations.

The DRM+ (Digital Radio Mondiale) system is the extension up to 300 MHz of the DRM digital radio broadcasting system. During 2010 three different trials were conducted in Brazil with DRM+ system in VHF band II (popularly called FM band). These trials were defined to have a big, medium and small coverage area for big, local and community broadcasters. For this purpose, different transmission powers were used. The transmission was done with only DRM signal in low power trial. In the high and medium power trials the transmission was done in “combined mode”, that is, the FM and DRM+ signals were transmitted in adjacent channels from the same transmission site. In this paper the results of these trials are explained and compared with theoretical values.