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Pilot-aided techniques are classically used to accomplish channel estimation in orthogonal frequency division multiplexing (OFDM) systems. However, those pilots occupy an important bandwidth which could have been allocated to data instead. Superimposed pilots have been proposed as substitutes to classical pilots and showed that with properly designed receivers, they are able to provide a satisfactory...
The ATSC 3.0 physical layer team has actively been identifying technology elements for adoption in the new ATSC 3.0 physical layer standard which significantly improves performance and robustness beyond current ATSC 1.0 levels. OFDM based waveforms, LDPC forward error correction are two such technologies which enable very robust broadcasts with low overhead for both stationary and mobile receivers...
This paper presents a database with video clips and results of subjective video quality tests oriented to Digital Terrestrial Television (DTT). It makes them publicly available for the research community in the Quality of Experience field, in order to train, verify and validate video quality assessment objective models. The database consists of the results of two sets of tests, each one with one hundred...
Video is being used in a variety of portable and low powered devices, via online/on-demand services, for personal communications or over heterogeneous/wireless sensor networks. Likewise, perceptual evaluation is being sought, to ensure video sequences maintain perceptual integrity. This raises a challenge, to bring high complexity perceptual algorithms into a low complexity environment. Existing perceptual...
Multimedia services distribution is very dependent on the quality of the communications link. Due to the nature of the related services, these are usually very sensitive to packet loss, delay and jitter, and hence service quality is immediately worsen in harsh scenarios. This paper proposes an OSI-Layer2 cooperative link layer scheme (known as GalaReS) that remarkably improves the multimedia content...
The present work covers a variety of available options for emergency warning broadcasting systems, focusing in broadcasting systems based mainly in television and radio systems. Also, we will make a detailed study of the emergency warning broadcasting system (EWBS), which uses the ISDB-T standard adopted in Peru, the majority of countries of Latin America, an also in other regions of the world.
This paper proposes a novel Resource Scheduling (RS) method by using Hybrid Broadcasting and Cellular Networks (HBCN). In this approach, the hot or common information is assigned with higher priority levels and is preferentially scheduled. The Equivalent Throughput (ET) and fairness are redefined and discussed. Simulations show the ETs of the networks are improved by using the proposed algorithms,...
In this paper, a low complexity algorithm is proposed for dual pseudorandom noise (PN) time domain synchronous OFDM (TDS-OFDM) systems, to simultaneously estimate the carrier frequency offset (CFO) and the sampling frequency offset (SFO). The second PN of every OFDM frame is used in the estimation. Firstly, SFO is estimated under maximum likelihood (ML) criterion. After that, a closed-form solution...
In this paper, an iterative zero forcing (IZF) detection scheme for generalised spatial modulation (GSM) is proposed to provide superior performance of bit error rate (BER) compared with other linear detection scheme, such as zero forcing (ZF) detection and minimum mean square error (MMSE) detection. Comparing to the optimal maximum likelihood (ML) detection, the proposed IZF detection also reduces...
Random access algorithm is critical for the performance of interactive broadcasting system. Random access with Dynamic Window Size and Random Access Slots(D-WS-RAS) is proposed as an efficient way to tackle this problem in the interactive broadcasting system. This algorithm is composed of three parts: utilize Bayes' rule to estimate the number of access, dynamically set backoff window size and dynamically...
The Advanced Television System Committee (ATSC) is currently developing the next-generation U.S. Digital Terrestrial Television (DTT) standard, known as ATSC 3.0. Two disruptive technologies for the physical layer are being evaluated, Layer Division Multiplexing (LDM) and Time Frequency Slicing (TFS). LDM consist in the transmission of a signal composed of two independent signals (layers) which are...
This paper presents a study that combines LDM (Layer Division Multiplexing) and SHVC (Scalable High Efficiency Video Coding) techniques to offer HD/UHD TV services in indoor scenarios. First, a theoretical study of the optimal configuration parameters for the LDM signal (such as constellation, code-rate and injection level) for indoor reception will be presented. Next, the results of some laboratory...
Thanks to the active development of IEEE 802.11, the performance of wireless local area networks (WLANs) is improving by every new edition of the standard facilitating large enterprises to rely on Wi-Fi for more demanding applications. The limited number of channels in the unlicensed industrial scientific medical frequency band however is one of the key bottlenecks of Wi-Fi when scalability and robustness...
In this paper, we present framing and multiple-physical layer pipe (PLP) structures for layered division multiplexing (LDM)-based next generation terrestrial broadcasting systems. As a framing structure, single-layer frames and multi-layer frames can be simultaneously transmitted by a time division multiplexing (TDM) approach. In addition to a conventional multiple-PLP strategy, which is basically...
This paper proposes a novel low-complexity layered division multiplexing (LDM) transmitter and receiver structures for next generation terrestrial broadcasting systems. The proposed LDM system not only has low complexity because it shares the OFDM-related chain, but also provides significant performance gain (4 to 6 dB) compared to traditional time division multiplexing (TDM) system.
Mobile video consumption through streaming is becoming increasingly popular. The video parameters for an optimal quality are often automatically determined based on device and network conditions. Current mobile video services typically decide on these parameters before starting the video streaming and stick to these parameters during video playback. However in a mobile environment, conditions may...
Disruption Tolerant Networks (DTNs) are characterized by lack of continuous network connectivity because of the limits of radio communication range, sparsity of mobile nodes, shortage of energy resources. There are many researches about data forwarding in DTNs, while limited work on providing efficient data access. In this paper, we propose an efficient cooperative caching scheme, which enables the...
Image quality assessment (IQA) has undergone a booming period during the last decade. Contrast change, being an important type of visual alteration for images, has not been seriously treated yet in the current IQA research. To address this problem, in this paper we propose a new reduced-reference (RR) IQA metric for contrast-changed images by exploiting local similarity information and global statistics...
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