LDM Core Services Performance in ATSC 3.0

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 superimposed together at different power levels. These two layer can be configured with the desired robustness and capacity. LDM enables the efficient provision of services addressed to mobile and fixed reception in a more efficient way than the classical Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM) since full bandwidth and transmission time are used in both layers. However, practical operation is restricted due to several implementation constraints such as the use of common parameters and transmitter blocks for both layers (e.g. a common time interleaver). The use of TFS allows for an improved frequency diversity by the distribution of the service data across multiple Radio Frequency (RF) channels instead of using a single RF channel. The paper investigates the potential gains provided by the increased frequency diversity with TFS in conjunction with LDM.

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In this paper, we present an efficient transmission method of multiple broadcasting services using layered division multiplexing (LDM) and scalable high efficiency video coding (SHVC) based on the next generation terrestrial digital broadcasting standard, advanced television systems committee 3.0. In a two-layer LDM system, each layer forms a physical layer pipe that carries base layer and enhancement layer video streams of SHVC, respectively. This combination of physical and presentation layers technologies can maximize channel utilization when multiple broadcasting services are delivered in a single radio frequency channel with different robustness and reception conditions. An intensive performance analysis is provided when the proposed combination of LDM and SHVC is compared with other approaches, such as time division multiplexing and/or high efficiency video coding simulcast broadcasting. Several performance measurements are also introduced, such as constant data rate measurement and constant quality measurement, which are used to evaluate the performance of video codecs in conjunction with different physical layer system parameters. A prototype hardware system with LDM and SHVC capable of selecting different parameter combinations is tested in the laboratory and in real field environments to verify the performance and feasibility of the proposed LDM and SHVC combination. Results show that the proposed LDM and SHVC combination provides significant gains on video service quality as well as reception robustness.

Recent broadcast standards support Layered Division Multiplexing (LDM) to achieve graceful degradation as signal quality degrades at the receiver. LDM is accomplished by using different constellations within the same Radio Frequency (RF) spectrum. LDM thus enables delivering multiple service tiers in a single broadcast channel. LDM when used in conjunction with scalable source coding codecs such as the Scalable extension of High Efficiency Video Coding (SHVC), further helps improve overall spectrum utilization and efficiency. In this paper we investigate a 2-tier broadcast LDM based service with one service tier aimed at lower video resolution such as 540p, 720p, 1080p for a mobile receiver (smaller/indoor antenna) and the other service tier targeting twice the video resolution of the lower tier, for stationary receivers (larger/outdoor antenna). The primary contribution of this paper is to identify 2-tier transmission configurations of interest to broadcasters and compare the spectrum and bitrate coding efficiency gains of an SHVC-based multi-tier service versus a simulcast (single layer) based multi-tier service for an Advanced Television Systems Committee (ATSC) 3.0 transmission system. Bitrate savings ranging from 38% and 57% is observed for the SHVC based layered system. For large coverage and pedestrian with a receiver test scenarios, channel utilization savings ranging from 23% to 46% is observed. For mobile and tablet in bedroom scenarios a smaller broadcast bandwidth savings ranging from 6% to 9% is observed.

Advanced Television Systems Committee (ATSC) 3.0 standard does not support the combined structure of layered division multiplexing (LDM) and multiple-input multiple-output (MIMO). Recently, previous works have evaluated the theoretical performance of LDM plus MIMO structure for enhanced system capacity. However, the practical performance for the structure has not been investigated yet over the realistic channels. This paper presents the practical performance of the layered MIMO broadcasting system evaluated by a working prototype. To this end, the ATSC 3.0-centric prototype transmitter and receiver are implemented. Based on the real hardware solutions, the laboratory-measured transmission performance is analyzed with respect to the crosstalk power within the MIMO channel, i.e., cross-polarization discrimination (XPD).

The most recent standard for broadcast services, Advanced Television System Committee—Third Generation (ATSC 3.0), has adopted co-located multi-antenna schemes and Layered Division Multiplexing (LDM) in order to increase the capacity and reliability compared to former Digital Terrestrial Television (DTT) systems. ATSC 3.0 has adopted both technologies separately, but no combination of them is planned yet. Compared to baseline LDM case, use of several antennas allows for diverse parametrization for each layer. This paper analyzes the potential combination of co-located Multiple-Input–Multiple-Output (MIMO) schemes with LDM. A trade-off analysis between complexity constraints and performance benefits is evaluated.

In a Single Frequency Network (SFN) for Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, the interferences induced by the multiple transmitters and/or repeaters using same frequency are unavoidable. To ease the interference handing in the SFN for ATSC DTV system, transmitter identification (TxID) signal is recommended in the ATSC terrestrial DTV system. The TxID signal is embedded in the ATSC DTV signal and transmitted from each transmitter and repeater within the SFN and in ATSC recommended practice (RP) A/111, Kasami sequence is recommended as the TxID signal. In this paper, we propose an additional data transmission scheme using the TxID signal. In the proposed scheme, the Kasami sequence not only acts as the conventional TxID of the SFN for ATSC terrestrial DTV system but also carriers the additional data bits on its polarity and the code phase.

The next generation digital TV (DTV) broadcast, namely Advanced Television System Committee (ATSC) 3.0, relies on substantial single frequency networks (SFN), each of which requires a studio to transmitter link (STL) to transmit data from the broadcast gateway (BG), leading to significant construction costs. Therefore, the wireless in-band distribution link (IDL) technology is proposed, which uses layered-division multiplexing (LDM) to transmit the STL data via wireless links from the BG to the SFN transmitters within the same spectrum as the broadcast services. In this paper, we propose the time synchronization and signal detection algorithm for wireless IDL systems with both unicast and broadcast signals. We introduce two multiplexing schemes, N-LDM and 3-LDM, and demonstrate their superiority over traditional frequency division multiplexing (FDM). To overcome the challenge of multi-access interference and synchronization errors caused by multipath, we develop a unique word (UW) design algorithm for transmitted signals and a double threshold correlation detection algorithm (DTCDA) that outperforms traditional ones. We employ a second threshold to enhance detection performance at low signal-to-noise ratios, and utilizes successive interference cancellation (SIC) to mitigate multiple-access interference. More importantly, our approach requires no knowledge of the unicast user number or channel state information. Simulation results validate the effectiveness of the proposed scheme.

New digital television standards are emerging to meet the demand for new services from TV broadcasters, as well as to support new high-resolution audio and video formats available on the market. In Brazil, the Brazilian Digital TV System (SBTVD) Forum defines the standard to be adopted. Among the currently available physical layer technologies, the Advanced Television Systems Committee (ATSC) 3.0 standard offers great flexibility in operating modes, depending on the broadcasters’ requirements and propagation conditions, for both fixed and mobile reception. This allows the system to be configured to balance robustness and transmission efficiency. This paper presents the performance test results in various mobile reception scenarios in the city of Rio de Janeiro, using an ATSC 3.0 signal with a transmission rate of 32.3 Mbps in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$</tex-math> </inline-formula> Multiple-Input Multiple-Output (MIMO) configuration. The results showed a reception success rate of 53.6%, with an increase in reception errors for Carrier-to-Noise Ratio (C/N) lower than 26 dB. Furthermore, reception errors were detected with greater intensity when the received signal level was below -70 dBm. Although the overall success rate was around 50%, the complementary metrics (C/N threshold, RSSI, and PLP0 error behavior) were consistent with theoretical expectations, demonstrating that ATSC 3.0 performs effectively under real urban mobility conditions at high spectral efficiency. ATSC 3.0 thus proved effective in broadcast transmission, meeting the needs for ultra-high-definition (UHD) audio and video broadcasting.

This report summarizes work currently underway in ATSC, the Broadcast Standards Association, relating to technical standards for ATSC 3.0. ATSC is an international, non-profit organization developing voluntary standards and recommended practices for broadcast television and multimedia data distribution. ATSC member organizations represent the broadcast, professional equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. ATSC also develops implementation strategies and supports educational activities on ATSC standards. ATSC was formed in 1983 by the member organizations of the Joint Committee on Inter-society Coordination (JCIC): the Consumer Technology Association (CTA), the Institute of Electrical and Electronics Engineers (IEEE), the National Association of Broadcasters (NAB), the Internet &amp; Television Association (NCTA), and the Society of Motion Picture and Television Engineers (SMPTE). This year, ATSC observes its 41st year of operation.

Single frequency network (SFN) enables efficient use of spectrum by allocating the same frequency among multiple transmitters. In order to efficiently design and manage the SFN, the Advanced Television Systems Committee (ATSC) 3.0 physical layer standard has adopted transmitter identification (TxID) technology which allows to measure the individual and/or whole network channel response, such as power and time delay of the broadcast signal from transmitters. Since TxID is embedded into the host ATSC 3.0 frame as radio frequency (RF) watermark, it is transparent to legacy ATSC 3.0 receivers and only a specially designed TxID analyzer is able to detect it. This paper presents new TxID detection methods that improve the detection performance of ATSC 3.0 TxID signal by resolving the problems and limitation of the conventional TxID detection method. The superiorities of the proposed detection methods are verified through computer simulation, laboratory test, and field trial.

This paper describes the architecture, functionality, and design of HDVO-a high definition video co-processor from Philips Semiconductors. The coprocessor design is modular and functionally complete, and is intended to be a part of and function as the primary picture/video composition hardware in any media-processor chip targeted at Digital Television (DTV) applications. Essentially a screen-refresh engine, HDVO can mix multiple video and graphics planes and is capable of scaling vertically and horizontally pictures of the highest resolution (1920/spl times/1080) specified in the DTV standard prescribed by the United States Advanced Television Systems Committee (ATSC). HDVO can efficiently process all (eighteen) ATSC video formats, including video generation for picture-in-picture display, and is currently being wed as an on-chip video coprocessor in the TM-2700 digital television chip. TM-8700 is the second generation of an architectural family of programmable multimedia processors from Philips Semiconductors and it not only supports all ATSC formats, from standard-definition to wide-angle high-definition video, but has also the power to handle High-Definition Television (HDTV) video and audio source decoding (high-level MPEG-2, AC-3 and ProLogic audio, closed captioning, etc.) as well as the flexibility to process advanced interactive services.

In this paper, the scheme that combines LDM(Layered Division Multiplexing) to the BST-OFDM(Band Segmented Transmission - OFDM) is proposed for the next-generation DTTB(Digital Terrestrial Television Broadcasting). In the proposed scheme for fixed reception, the parity-check matrix of the conventional LDPC code whose length is 69120 is extended. After that, the extended parity bits are generated by the parity-check matrix and modulated. These modulated symbols are multiplexed by LDM to symbols for mobile reception. The performances of the proposed scheme are evaluated by computer simulations under AWGN(Additive White Gaussian Noise), and the required CNR(Carrier to Noise Ratio) of fixed reception can be improved by the proposed scheme. Furthermore, it is possible to decode received symbols even with existing receivers that don't support LDM demodulation by using the proposed extended LDPC code for fixed reception.

The discussion of mobile multimedia broadcasting technologies and service implementation in this chapter is limited to the broadcasting network based scheme can be received by portable or hand-held devices with a small screen. Similar to DTTB systems, digital mobile multimedia broadcasting systems are designed for high-data-throughput (to support multiple low-data-rate services) transmission through wireless channels (VHF/UHF bands in terrestrial, S- or L-band for satellite networks). The chapter summarizes the features of DVB-H, Advanced Television Systems Committee (ATSC)-M/H, China Multimedia Mobile Broadcasting (CMMB), and the new released DVB Next Generation Broadcasting System to Handheld (NGH) standards with the focus on the technical merits of reliable transmission under wireless, mobile environment and the robust reception using the portable or hand-held devices. ATSC-Mobile/Handheld (ATSC-M/H) is the standard for the DTV mobile transmission developed by the ATSC in 2007. The ATSC-M/H system shares the same RF channel of the traditional ATSC broadcast services.

Layered Division Multiplexing (LDM) is a Non-Orthogonal Multiple Access (NOMA) scheme initially proposed for application in digital terrestrial television standards (ATSC 3.0) providing increased system performance, robustness, throughput and flexibility. Lately, its use on satellite communications has been studied. Results confirm throughput gains with respect to Time Division Multiplexing if services being multiplexed have unbalanced data rates and reception thresholds. This paper targets a deeper insight on the impact of the injection level on the LDM system performance. The paper proposes a system evaluation prototype and a carefully designed simulation methodology. The results show gains ranging from 10% to 65% depending on the injection level applied.