Digital Video Broadcasting For Handheld Research Articles

Signal-to-noise maximization in DVB-H receivers using reconfigurable matching networks

The quality of DVB-H (Digital Video Broadcasting for Handheld) signals in consumer receiver is usually related to signal-to-noise ratio (SNR). The application of reconfigurable matching networks (RMN) in DVB-H systems has been recently studied, but its effect in receiver noise has not been taken into account. In this paper, the RMN effect in noise power will be addressed, obtaining a closed expression for SNR under mismatch conditions and the presence of the RMN. Moreover, the antenna can cause some degradation due to environmental variation, which will be also taken into account. Improvements in SNR using the RMN will be reported in both situations.

A fine carrier recovery algorithm robustto doppler shift for OFDM systems

In this paper, a fine carrier recovery algorithm is proposed to maintain the synchronization even in a severe Doppler shift for orthogonal frequency division multiplexing (OFDM) systems such as digital video broadcasting for handheld (DVB-H), DVB for terrestrial (DVB-T) and DVB-T2. The proposed algorithm estimates the frequency offset by utilizing correlation values in the received OFDM symbols by adding intentional frequency offsets. Its performance is compared with conventional algorithms for the DVB-H system in fading with Doppler.

Performance degradation due to antenna impedance variability in DVB-H consumer devices

The quality of DVB-H (Digital Video Broadcasting for Handheld) signals in a consumer receiver is usually analyzed by means of the BER (Bit Error Rate). This measure has been studied from a mobile channel perspective, and different signal processing algorithms have been proposed to mitigate its degradation. However, the effects of the hardware at the receiver are also important. The antenna can cause some degradation due to variations in field magnitudes, like the radiation pattern, but also in circuit magnitudes, as mismatching. In this paper, we propose an algorithm to evaluate the degradation on the BER due to consumer equipment effects which cause certain variability in the antenna impedance and consequently in the SNR (Signal to Noise Ratio). We also evaluate the theoretical improvement when a mitigation circuit (an ideal Antenna Tuning Unit) is included in the DVB-H receiver design.

Performance improvement of mobile DVB-H terminals using a reconfigurable impedance tuning network

DVB-H (digital video broadcasting for handheld) is one of the technology standards for the transmission of digital TV to handheld receivers such as mobile phones or PDAs. Antenna design for DVB-H terminals is challenging due to the size limitation and as a result, the antenna presents large mismatches. To address this issue, we propose the use of a reconfigurable tuning network to reduce the mismatch (or the antenna size for a given mismatch) between the antenna and the RF front-end in a DVB-H terminal. This technique offers some advantages over other proposed alternatives and improves the antenna realized gain, as well as the overall efficiency of the DVB-H receiver.

Effects of power amplifier distortion and channel estimation errors on the performance of DVB-H system with multiple-antenna receiver

Orthogonal frequency division multiplexing (OFDM) is extensively used in modern digital television terrestrial broadcasting (DTTB) systems, such as the OFDM based Digital Video Broadcasting for Handheld (DVB-H) system, to support high performance bandwidth-efficient multimedia services. As a special format of multiple input multiple output (MIMO), multiple-antenna diversity reception can be used to improve the signal quality of the multiple-antenna reception OFDM based DVB-H systems. The same as the single-in single-out (SISO) OFDM systems, the MIMO-OFDM systems are sensitive to the power amplifier distortion at the transmitter and the channel estimation errors at the receiver. The objective of this paper is to research and analyze the compositive effects of power amplifier distortion and channel estimation errors on the performance of the DVB-H system with multiple-antenna receiver under multipath fading channel. Both the nonlinearities and the memory effects are used to model the power amplifier behavior. A closed form of symbol error probability is derived for the DVB-H system with multiple-antenna receiver in the presence of power amplifier distortion and channel estimation errors under multipath fading channel. Theoretical results show closely matching with those obtained by simulations for the DVB-H system with multiple-antenna receiver in the presence of power amplifier distortion and channel estimation errors under multipath fading channel.

Antenna effects in DVB-H mobile rebroadcasters

Digital video broadcasting for handheld (DVBH) is one of the wireless technologies that provide modern digital television services. The main objective of this paper is to propose a method to evaluate the performance of mobile rebroadcaster in terms of symbol error rate, taking into account antenna effects and the angle of arrival statistics. A correction factor is derived from concepts as the mean effective gain, which joined to a closed-form expression for the symbol error probability, allows predictions about the antenna impact on the broadcaster. The quantitative evaluation of the analysis identifies an important SNR reduction from 4 dB to 10 dB, depending on the environment.

Implementing Statistical Multiplexing in DVB-H

A novel technique for implementing statistical multiplexing (StatMux) of broadcast services over Digital Video Broadcasting for Handhelds (DVB-H) channels is proposed. DVB-H uses a time-sliced transmission scheme to reduce the power consumption used for radio reception part in DVB-H receivers. Due to the time-sliced transmission scheme, the implementation of known StatMux methods for DVB-H application presents some challenges which are addressed in this paper. The proposed StatMux technique is implemented in conjunction with the time-slicing transmission scheme. The combination is similar to a time division multiplexing (TDM) scheme. The proposed StatMux method considerably decreases the end-to-end delay of DVB-H services while it maximizes the usage of available bandwidth. Moreover, the proposed method can effectively decrease the channel switching delay of DVB-H services. Simulation results show a high performance for the proposed StatMux method.

Implementing a DVB-T/H Receiver on a Software-Defined Radio Platform

Digital multimedia broadcasting is available in more and more countries with various forms. One of the most successful forms is Digital Video Broadcasting for Terrestrial (DVB-T), which has been deployed in most countries of the world for years. In order to bring the digital multimedia broadcasting services to battery-powered handheld receivers in a mobile environment, Digital Video Broadcasting for Handheld (DVB-H) has been formally adopted by ETSI. More advanced and complex digital multimedia broadcasting systems are under development, for example, the next generation of DVB-T, a.k.a. DVB-T2. Current commercial DVB-T/H receivers are usually built upon dedicated application-specific integrated circuits (ASICs). However, ASICs are not flexible for incoming evolved standards and less overall-area efficient since they cannot be efficiently reused and shared among different radio standards, when we integrate a DVB-T/H receiver into a mobile phone. This paper presents an example implementation of a DVB-T/H receiver on the prototype of Infineon Technologies' Software-Defined Radio (SDR) platform called MuSIC (Multiple SIMD Cores), which is a DSP-centered and accelerator-assisted architecture and aims at battery-powered mass-market handheld terminals.

Joint Video Coding and Statistical Multiplexing for Broadcasting Over DVB-H Channels

A novel joint video encoding and statistical multiplexing (StatMux) method for broadcasting over digital video broadcasting for handhelds (DVB-H) channels is proposed to improve the quality of encoded video and to decrease the end-to-end delay in a broadcast system. The main parts of end-to-end delay in a DVB-H system result from a time-sliced transmission scheme that is used in DVB-H and from the bit rate variations of service bit streams. The time-sliced transmission scheme is utilized in DVB-H to reduce the power consumption of DVB-H receivers. Variable bit rate (VBR) video bit streams are used in DVB-H to improve the video quality and compression performance. The time-sliced transmission scheme has increased the channel switching delay, i.e., switching to a new audio-visual service, in DVB-H. The used VBR bit streams increase the required buffering delays in the whole system. The different parts of end-to-end delay in a DVB-H system can be affected by the used video encoding and multiplexing methods. Different scenarios for encoding and StatMux of video sources for DVB-H application are studied in this paper. Moreover, a new method for jointly encoding and StatMux of video sources is proposed that not only decreases the end-to-end delay but also improves the average quality of compressed video by dynamically distributing available bandwidth between the video sources according to their relative complexity. Performance of the proposed method is validated by simulation results.

An efficient approach for DVB-H handover in DVB-H/UMTS hybrid networks

Handover in Digital Video Broadcasting for Handhelds (DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries. A good handover control can improve the power efficiency and gain much better reception quality. This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System (UMTS) hybrid network, which moves the main handover function from the terminals to the networks, so that it reduces the operation complexity of the terminals and increases the power saving. When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons, the UMTS networks may offer the same service to users to make the service continuous. As the UMTS networks have the topology of the DVB-H networks, by communicating with the terminals, the UMTS networks can help the terminals to predict the handover, and avoid unnecessary handover.

Performance analysis of the DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency division multiplexing (OFDM) is extensively used in modern digital television terrestrial broadcasting (DTTB) systems, such as the OFDM based Digital Video Broadcasting for Handheld (DVB-H) system, to support high performance bandwidth-efficient multimedia services. OFDM based DVB-H system is very sensitive to the nonlinear distortion at the transmitter and the carrier frequency offset at the receiver. The objective of this paper is to research and analyze the performance of the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel. A closed form of symbol error probability is derived for the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel. Theoretical results show closely matching with those obtained by simulations for the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel.

Intersystem Soft Handover for Converged DVB-H and UMTS Networks

Digital video broadcasting for handhelds (DVB-H) is the standard for broadcasting Internet Protocol (IP) data services to mobile portable devices. To provide interactive services for DVB-H, the Universal Mobile Telecommunications System (UMTS) can be used as a terrestrial interaction channel for the unidirectional DVB-H network. The converged DVB-H and UMTS network can be used to address the congestion problems due to the limited multimedia channel accesses of the UMTS network. In the converged network, intersystem soft handover between DVB-H and UMTS is needed for an optimum radio resource allocation, which reduces network operation cost while providing the required quality of service. This paper deals with the intersystem soft handover between DVB-H and UMTS in such a converged network. The converged network structure is presented. A novel soft handover scheme is proposed and evaluated. After considering the network operation cost, the performance tradeoff between the network quality of service and the network operation cost for the intersystem soft handover in the converged network is modeled using a stochastic tree and analyzed using a numerical simulation. The results show that the proposed algorithm is feasible and has the potential to be used for implementation in the real environment.

Robust Plateau Removed Synchronization Techniques for Multiple-antenna OFDM-Based DVB-H Receivers

As a special format of multiple input multiple output (MIMO), multiple-antenna diversity reception can be used to improve the signal quality of the orthogonal frequency division multiplexing (OFDM) based digital video broadcasting for handheld (DVB-H) systems. Under multipath fading channels, synchronization methods proposed for the single input single output (SISO) OFDM systems may be to fail if they are directly applied to the multiple-antenna OFDM-based DVB-H receivers. In this paper, a plateau removed maximum likelihood synchronization scheme is proposed for the multiple-antenna OFDM-based DVB-H receivers. Compared to the conventional maximum likelihood multiple antenna OFDM synchronization scheme, the proposed scheme not only removes the timing ambiguity caused by the plateau problem and has better detection capability but also is robust to different multipath fading channels. System performance studies are used to verify the efficiency of the proposed scheme for the multiple-antenna OFDM-based DVB-H receiver under different fading channel situations.

Incorporating digital repeaters into the soft handover standard in digital video broadcasting for handhelds

Digital Video Broadcasting for Handhelds (DVB-H) is a standard for broadcasting IP data to portable devices. This paper proposes and analyses the Repeater-Aided Soft Handover (RA_handover) algorithm for a DVB-H receiver with Multiple Input-Multiple Output (MIMO) antennas and presents the benefits of implementing the RA_handover compared with a handover process without repeaters. Simulation models are developed to analyse the RA_handover approach. It is shown that the RA_handover could greatly improve the quality of service and consume much less front-end battery power than the handover method without repeaters. This paper also provides valuable outcomes for service providers and standard policymakers.

A survey of handover algorithms in DVB-H

Digital video broadcasting for handhelds (DVB-H) is a standard for broadcasting IP Datacast (IPDC) services to mobile handheld terminals. Based on the DVB-T standard, DVB-H adds new features such as time slicing, MPE-FEC, in-depth interleavers, mandatory cell id identifier, optional 4K-modulation mode and the use of 5 MHz bandwidth in addition to the usually used 6, 7, or 8 MHz raster. IPDC over DVB-H is proposed for ETSI to complement the DVB-H standard by combining IPDC and DVB-H in an end-to-end system. Handover in such unidirectional broadcasting networks is a novel issue. In the last few years since the birth of DVB-H technology, great attention has been given to the performance analysis of DVB-H mobile terminals. Handover is one of the main research topics for DVB-H in mobile scenarios. Better reception quality and greater power efficiency are considered to be the main targets of handover research for DVB-H. New algorithms for different handover stages in DVB-H have been the subject of recent research and are currently being studied. Further novel algorithms need to be designed to improve the mobile reception quality. This article provides a comprehensive survey of the handover algorithms in DVB-H. A systematic evaluation and categorization approach is proposed based on the problems the algorithms solve and the handover stages being focused on. Criteria are proposed and analyzed to facilitate designing better handover algorithms for DVB-H that have been identified from the research conducted by the authors.

Optimum Doppler compensation scheme for DVB-H receivers

The Doppler spread in digital video broadcasting for handheld (DVB-H) terminals receivers is responsible for the inter-carrier interference (ICI). Proposed is a new scheme to estimate and compensate the ICI term with reduced hardware complexity, especially suited for mobile terminals. Simulation results compare the proposed technique with another existing method, showing similar performances, with a significant hardware reduction.