Ladislav Polak

DVB-T and DVB-T2 performance in fixed terrestrial TV channels

This paper deals with the DVB-T (Digital Video Broadcasting-Terrestrial) and DVB-T2 (DVB-2nd Generation Terrestrial) standards and their transmission performance in fixed TV channels. For the analysis and simulation of performance of both standards, classical Ricean and Rayleigh multipath fading channels with 20 independent paths were used. Simulation results of the BER (Bit Error Ratio) before and after FEC (Forward Error Correction) decoding were evaluated and compared for DVB-T and DVB-T2 standards. Dependences of MER (Modulation Error Ratio) on C/N (Carrier-to-Noise Ratio) were also obtained for both standards. Moreover, optimal configuration of the new DVB-T2 system for broadcasting of HDTV (High Definition Television) services was explored. Appropriate applications for these simulations were developed in MATLAB. Finally, achieved results are evaluated and clearly discussed.

Influence of mobile network interfering products on DVB-T/H broadcasting services

In this paper the influence of mobile network interfering products on DTV (Digital Television) services is explored and evaluated. More precisely, the overall aim of this paper is to measure and show the interactions between the mobile (GSM) and digital terrestrial television (DVB-T/H) broadcasting networks and services. In the DVB-T/H system configuration, the TPS (Transmission Parameter Signaling) carriers keep the receiver informed about the main system parameters. Disturbance of these carriers by interfering products of GSM network and degradation of DVB-T services are also explored and described. Theoretical backgrounds, general workplace and the principle of the measuring method is also introduced and briefly described. For the evaluation of the impact of mobile networks on the signal quality of DTV services the BER (Bit Error Ratio), MER (Modulation Error Ratio) ratios and constellation imperfections are used. Finally, the obtained results are evaluated and clearly described.

Exploring and measuring the co-existence between LTE and DVB-T2-Lite services

The development and effective use of wireless communication systems to provide mobile services is rapidly increasing. Nowadays, the worlds most perspective standards to provide wireless multimedia services in high quality are LTE (Long-Term Evolution) and DVB-T2 Lite (DVB-2nd Generation Terrestrial). On the other hand, these wireless multimedia systems can many times operate in a neighboring frequency spectrum. Therefore, as a result, numerous co-existence scenarios are possible. The focus of this paper is to explore and measure the co-existence between LTE and DVB-T2 Lite multimedia services. Theoretical backgrounds of the coexistence scenarios, general workplace and the principle of the measuring method of the influence of the LTE services on DVB-T2 services and vice versa are clearly presented and described. Furthermore, deeper investigation of the mutual influence of the DVB-T2 system on the LTE system is also explored and graphically illustrated. Finally, all obtained results are evaluated and future work is outlined.

DVB-H and DVB-SH-A performance and evaluation of transmission in fading channels

This paper deals with the examination of the transmission distortions of the standards DVB-H and DVB-SH-A in portable and mobile TV over fading channels. These channel profiles introduce and respect Doppler shift. Appropriate applications for this simulation (DVB-H and DVB-SH-A transmission) were developed in MATLAB. Simulation results of the BER after Viterbi decoding (DVB-H) and after turbo decoding (DVB-SH-A) were obtained and compared. Dependences of MER on C/N for QPSK and 16QAM modulations were obtained for both standards. Finally, achieved results were evaluated and discussed.

Exploring of the DVB-T/T2 performance in advanced mobile TV fading channels

The second generation terrestrial standard DVB-T2 has a more flexible approach of the system parameters for the mobile and portable digital television broadcasting then DVB-T. This paper deals with the exploring of the DVB-T/T2 transmission performance in advanced mobile television channel models. For the analysis and simulation there were used advanced mobile fading channel models called Vehicular Urban and Motorway Rural that respects fast moving receiver in a car and Doppler shift. Detailed dependences of the bit error ratio before and after channel decoding and according modulation error ratio on the carrier-to-noise ratio are the main results of this work. Applications for the exploring of DVB-T/T2 performance were completely created in MATLAB. In advance, the results of the simulations were completely verified on real measurement data to be sure about their validity.

Exploring and Measuring Possible Co-Existences between DVB-T2-Lite and LTE Systems in Ideal and Portable Fading Channels

From the point of technical innovations the development and standardization of Digital Video Broadcasting - 2 nd Generation Terrestrial (DVB-T2) and Long-Term Evolution (LTE) systems are definitely the most significant results in the last decade. These systems have a very high potential to fulfill the highest user requirements, but they can operate in the same frequency spectrum. As a result, different co-existence scenarios can occur. In this paper, we explore and measure the co-existence between DVB-T2-Lite (e.g. portable TV) and LTE multimedia services in ideal and portable fading channel models. Theoretical backgrounds of the investigated co-existence scenarios, proposal and realization of an appropriate workplace for their measuring and evaluation are presented and described. Moreover, deeper investigation of the mutual influence of the DVB-T2 system on the LTE one is also explored and graphically illustrated. The obtained results show that these co-existences could be critical for both systems from the point of providing multimedia services with a constant level of Quality of Services (QoS).

Measurement of the DVB-T2 with 256QAM rotated constellation and 32K extended mode in relation to variable pilot patterns

Second generation digital terrestrial television broadcasting, in this paper represented by the DVB-T2 standard, has a more flexible approach of the system parameters by defining up to eight pilot patterns. Selection of the best pattern and related DVB-T2 system parameters can be adjusted in a real broadcasting network based on operator demands. This paper deals with exploring of the DVB-T2 system performance in different transmission channels and evaluates its dependence on the type of the pilot pattern used towards real DVB-T2 terrestrial network implementation. A fixed reception scenario of broadband multimedia system services is considered with HDTV video image quality for a very convenient 256QAM rotated constellation and 32K extended mode. Several terrestrial channel models are also respected, like reference Gaussian channel and standardized Ricean and Rayleigh fixed fading channels with 20 echo paths and variable delays. Dependences of the bit error rates before and after a highly efficient LDPC decoding and consequent modulation error on the carrier-to-noise ratio for different pilot patterns are the main results of our work. Finally, our experimental results are compared with the simulated and theoretical values from the ETSI standard to be sure about their validity.

Algorithms for vowel recognition in fluent speech based on formant positions

This paper deals with Czech vowels and two algorithms for vowel detection in fluent speech. Basic algorithm is based on the frequencies of first two formants F1 and F2 determining the individual vowels. The accuracy of basic algorithm is susceptible to the quality of recorded speech signal because voice distortion and surrounding noise can cause a high rate of false vowel detection. Second algorithm is an improved version on the first one extended by retroactive checking of vowel duration. Both algorithms were applied on created speaker database containing 5 female and 13 male native speakers. Better results were obtained using the improved algorithm which reduced false detection of vowel segments over all speakers and all vowels by 36.7% at average.

Coexistence Between DVB-T/T2 and LTE Standards in Common Frequency Bands

In the last decade, fulfilling the growing users’ expectations on the quality of provided multimedia services is one of the biggest challenges for different wireless communication systems. However, many times, different kinds of wireless systems can operate in the same (shared) frequency band. Such coexistence generally negatively affects the performance of the systems colliding. This is especially true for the widely used Digital Video Broadcasting-Terrestrial (DVB-T) or upcoming DVB-2nd Generation Terrestrial (DVB-T2) and Long-Term Evolution (LTE) standards, operating in Europe. Hence, the aim of this paper is to explore the impact of interfering mobile telecommunication services on the mobile TV services provided by LTE and DVB-T/T2 systems in the same frequency band. For the simulation of the coexistence between the LTE and DVB-T/T2 services on the physical layer level, an appropriate method is proposed and complex simulation tools are coupled. The results, presented as a dependence of modulation error ratio at the receiver input and bit error ratio at the channel decoder input on the spectral level ratio, show comparable performances for DVB-T and DVB-T2 systems. Results from simulations are verified by laboratory measurements and should help to better understand the influence of co-channel interferences from LTE mobile networks on DVB-T/T2 networks for mobile transmission scenarios.

Study of the coexistence between ZigBee and Wi-Fi IEEE 802.11b/g networks in the ISM band

The number of wirelessly connected multimedia devices and different communication standards, supported by these devices, is rapidly increasing. However, the appropriate frequency bands (licensed and unlicensed) for data transmission by these standards are very limited. The rising density of wireless networks and their coexistence in the same or adjacent radio frequency (RF) spectrum can significantly decrease the quality of provided services. This paper deals with the study of coexistence between ZigBee (IEEE 802.15.4) and Wireless Fidelity (Wi-Fi) networks, including the IEEE 802.11b/g standards, which operate in the unlicensed Industrial, Scientific and Medical (ISM) band at 2.4 GHz. Firstly, a general simulation model was developed. Secondly, to verify results from simulation by measurement, an appropriate laboratory workplace in anechoic chamber was proposed and realized. Such setup and the measurement principle are briefly described in this paper too. Impact of the IEEE 802.11b/g networks on the ZigBee and vice versa is evaluated by dependence of bit error rate (BER) and error vector magnitude (EVM) on the power imbalance between power levels of considered RF signals, respectively.